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| Hepatology, 1999 Apr, 29(4), 1057 - 63 Vascular endothelial growth factor production in peritoneal macrophages of cirrhotic patients: regulation by cytokines and bacterial lipopolysaccharide; Perez-Ruiz M et al.; Vascular endothelial growth factor (VEGF) is an angiogenic peptide with vascular permeability and relaxing properties . This study assessed whether peritoneal macrophages of cirrhotic patients can be up-regulated to produce VEGF under proper stimulatory conditions . Macrophages were isolated from ascites . VEGF protein secretion and mRNA expression were measured in basal conditions and after stimulation with lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF-alpha), and interleukin-1 (IL-1) . These substances induced a time- and dose-dependent increase in both VEGF production and transcript expression . Assays with actinomycin D showed that VEGF mRNA induction is secondary to both higher VEGF gene transcription and mRNA stability . Ascites and plasma concentration of VEGF was also measured in cirrhotic patients with (n = 15) and without (n = 10) spontaneous bacterial peritonitis (SBP) . Plasma values did not differ between both groups of patients . However, ascites VEGF levels were higher in SBP patients than in noninfected cirrhotic patients (710 +/- 183 vs . 94 +/- 15 pg/mL; P <.025) . These results indicate that cytokines and LPS markedly increase VEGF protein secretion and mRNA expression in macrophages of cirrhotic patients, and suggest that this substance could be an important mediator of the pronounced arterial vasodilation frequently occurring in SBP patients. FEBS Lett, 1999 Feb 26, 445(2-3), 384 - 8 Key role of barstar Cys-40 residue in the mechanism of heat denaturation of bacterial ribonuclease complexes with barstar; Protasevich II et al.; The mechanism by which barnase and binase are stabilized in their complexes with barstar and the role of the Cys-40 residue of barstar in that stabilization have been investigated by scanning microcalorimetry . Melting of ribonuclease complexes with barstar and its Cys-82-Ala mutant is described by two 2-state transitions . The lower-temperature one corresponds to barstar denaturation and the higher-temperature transition to ribonuclease melting . The barstar mutation Cys-40-Ala, which is within the principal barnase-binding region of barstar, simplifies the melting to a single 2-state transition . The presence of residue Cys-40 in barstar results in additional stabilization of ribonuclease in the complex. Pathol Res Pract, 1999, 195(2), 89 - 92 The role of persisting infections in the pathogenesis of pulmonary emphysema . Electron microscopy reveals a probable bacterial colonization of the alveolar space and the bronchioles; Theegarten D et al.; Lung volume reduction surgery (LVRS) yields resection specimens from patients with advanced pulmonary emphysema . Regarding the development of lung function parameters, recent results obtained by light microscopy revealed an unfavorable prognosis in patients with remarkable inflammation, particularly in the bronchioli . Tissue from ten patients (alpha1-antitrypsin level in the normal range) was furthermore investigated by electron microscopy . Scanning electron microscopy shows 0.4-0.6 micron spherical bodies variably densely arranged in the whole alveolar space and in the bronchioles of all patients . These bodies are mostly seen on the microvilli of type II pneumocytes . An immunological reaction with activation of macrophages and granulocytes occurs simultaneously . Macrophages show cytoplasmic extensions to the spherical bodies, which exhibit a cellular membrane but no cellular wall . This favors the diagnosis of bacterial colonization of the alveolar space and the bronchioles by mycoplasmas or L-forms of other bacteria . As patients undergoing lung volume reduction surgery are under optimal medical treatment and without any infection clinically, these findings appear to be relevant for the pathogenesis and/or progression of pulmonary emphysema. Pediatr Pulmonol Suppl, 1999, 18, 141 - 3 The role of viral and atypical bacterial pathogens in asthma pathogenesis; Johnston SL; The recent development of PCR for the diagnosis of respiratory viral infections has permitted studies revealing the importance of virus infections in acute exacerbations of asthma . Several studies implicate rhinovirus as the major virus type in mild and severe wheezing illness in children of all age groups, but particularly over 1 year of age . Rhinoviruses have been shown to replicate in the lower airway, suggesting that virus induced asthma exacerbations result from direct inoculation, spread of the virus from the upper to the lower airway . The importance of RS virus infection in bronchiolitis and wheezing in infants has been reaffirmed . Recent studies using PCR to detect C pneumoniae, suggests a high prevalence of chronic infection in asthmatic children, and that the immune response to this organism may play a pathological role in asthma . These studies now require confirmation with larger carefully controlled studies. Biochem Mol Biol Int, 1999 Jan, 47(1), 117 - 25 The polarization model in bacterial photosynthesis; Borisov AYu et al.; The widely accepted model of reaction center /RC/ functioning is proved to come into contradiction with some recent data . In particular, it cannot explain why only a minor part of electronic excitations (approximately 10%) escapes from excited RC special pairs back to antenna BChls . Therefore we believe that the model must be substantially modernized . In 1981 we developed a new model/1,2/ . We suggested a femtosecond state to precede primary e-transfer reaction due to reorientation of water molecule dipole in the electric field of excited RC dimer . This mechanism is responsible for energy trapping before the primary e-transport occurs . During last years his mechanism got support from various experimental works . Now this polarization model claims to fit all reliable experimental data at least in bacterial photosynthesis. Acta Crystallogr D Biol Crystallogr, 1999 Feb, 55 ( Pt 2), 549 - 51 Crystallization of L-aspartate oxidase, the first enzyme in the bacterial de novo biosynthesis of NAD; Bacchella L et al.; The flavoenzyme L-aspartate oxidase from Escherichia coli was crystallized using the hanging-drop vapour-diffusion technique with PEG 4000 as precipitant . The crystals belong to space group P3121 (or P3221) with unit-cell parameters a = b = 84.9, c = 159.9 A . A solvent content of 42% corresponds to a monomer (60 kDa) in the asymmetric unit . A complete 2.8 A resolution data set was collected using a rotating-anode X-ray generator. Acta Crystallogr D Biol Crystallogr, 1999 Apr, 55 ( Pt 4), 915 - 7 Crystallization and preliminary x-ray diffraction studies of a novel bacterial esterase; Bourne PC et al.; A novel bacterial esterase has been crystallized in two forms suitable for X-ray diffraction studies . Crystals have been obtained by vapour-phase diffusion at 290 K using ammonium sulfate as precipitant . The first crystals grew in space group C2 with unit-cell parameters a = 134.7, b = 55.8, c = 110.3 A, beta = 125.1 degrees . A monoclinic data set has been collected to 2.0 A resolution . Microseeding yielded a second crystal form which grew in space group P212121 with unit-cell parameters a = 57.1, b = 115.4, c = 130.4 A . Native data from these crystals have been collected to 1.6 A resolution . A molecular envelope has been determined using an uranyl acetate derivative for phase calculation. Lab Anim Sci, 1999 Feb, 49(1), 62 - 9 Bacterial lipopolysaccharide induces a conduction block in the sciatic nerves of rats; Brown RF et al.; A single injection of Escherichia coli lipopolysaccharide (LPS; intraperitoneally {i.p.} and intravenously {i.v.}) reliably induces peripheral nerve disturbances in the hindlimbs of inbred Australian albino Wistar (AaW) rats . In the series of experiments presented here, we aimed to characterize this syndrome by examining electrophysiologic, immunologic, and immunochemical features . The LPS-induced neurologic sequelae in AaW rats were transient, at least partly reversible by drug treatment, and were not associated with any detectable neuropathologic findings by light microscopy . Neurologic sequelae were prevented by administration of dexamethasone and by pretreatment with the macrophage inhibitor gadolinium chloride, suggesting that they were caused by LPS-induced activation of peripheral macrophages . Sequelae were associated with early decreases in compound muscle-action potential amplitudes, indicating impaired functioning of either proximal sciatic nerve axons and/or neuromuscular synapses . Spinal somatosensory-evoked potential latencies also were increased, indicating impaired somatosensory function at the sciatic nerve, dorsal roots, spinal cord, and/or postsynaptic interneurons, although the precise location of impairment could not be delineated . Similarities between this syndrome and immune-mediated polyneuropathies in humans are discussed. Fogorv Sz, 1999 Feb, 92(2), 45 - 50 {Bacterial flora of odontogenic and non-odontogenic inflammations of the oro-facial region}; Szontagh E et al.; Samples were collected from 34 patients after extraoral incision in case of infections of oro-facial region (29 odontogen and 5 non odontogen) . The authors examined the prevalence, ration and susceptibility of the isolated bacteria to antibiotics . The 98-100% of the bacteria has found were sensitive to Clindamycin and Amoxicillin/Clavulan acid . These antibiotics could be the first choice to treat the above mentioned diseases. Arch Surg, 1999 Mar, 134(3), 287 - 92 Enteral nutrition prevents bacterial translocation but does not improve survival during acute pancreatitis; Kotani J et al.; OBJECTIVE: To evaluate the effect of enteral nutrition (EN) in attenuating bacterial and/or endotoxin translocation, maintaining immune responsiveness, and improving outcome in early acute pancreatitis (AP) in Wistar male rats . DESIGN: Acute pancreatitis was induced in rats receiving total parenteral nutrition (TPN) (AP/TPN group) (n=34) and EN (AP/EN group) (n=35) by pressure injection of 1% deoxycholate into the biliopancreatic duct (0.6 mg/kg of body weight) . Rats in the sham/TPN and sham/EN groups (n=10 each) underwent laparotomy without induction of AP . Catheters for TPN and EN were placed into the external jugular vein and jejunum, respectively . Rats were infused with Ringer lactate solution for 48 hours followed by TPN in the AP/TPN and sham/TPN groups, and EN in the AP/EN and sham/EN groups until day 7 . The fluid volume and energy (calories) intake were similar in all groups . SETTING: Medical school research laboratory . MAIN OUTCOME MEASURES: Survival, blood endotoxin level, villus height, 5-bromo-2'-deoxyuridine (BrdU) uptake in the jejunum and ileum, bacterial culture of mesenteric lymph nodes, and CD4/CD8 ratio of T cells in mesenteric lymph nodes, spleen, and peripheral blood . RESULTS: There was no difference in survival and pancreatic healing between the AP/TPN and AP/EN groups . Colony-forming units of the mesenteric lymph nodes and the endotoxin level were significantly lower in the AP/EN group than in the AP/TPN group (P<.05) . Villus height and BrdU intake was significantly higher in the AP/EN group than in the AP/TPN group (P<.05) . The CD4/CD8 ratio of T cells in spleen and peripheral blood was higher in the AP/EN group than in the AP/TPN group (P<.05), whereas there was no difference in mesenteric lymph nodes . CONCLUSIONS: Jejunal administration of EN is well tolerated in early AP, maintains immune responsiveness and gut integrity, and reduces bacterial and/or endotoxin translocation . However, compared with TPN, EN does not improve outcome . These results suggest that factors other than bacterial and/or endotoxin translocation may be responsible for mortality in this rat model of early AP . However, additional studies of both early bacterial and/or endotoxin translocation and late assessment of outcome are indicated. Scand J Clin Lab Invest, 1998 Dec, 58(8), 661 - 8 A modified fast micro method in agarose for isotype, allotype, light chain and idiotype-specific analysis of antibody clonotypes to bacterial virulence antigens; Nagao AT et al.; A modified fast micro method for spectrotypic/clonotypic analysis of human IgG1-4 antibodies against bacterial virulence antigens of polysaccharide or protein nature is described . Serum samples of as small volumes as 0.5 microliter were isoelectrically focused in micro agarose gels made in plexiglass matrices and blotted using immunoaffinity-mediated capillary blotting onto nitrocellulose membranes previously coated with antigen . The bands of the antigen-specific antibodies were identified with respect to isotypes, light chain types, allotypes or idiotypes by incubating the nitrocellulose membranes with mouse monoclonal anti-human IgG subclass antisera and then with alkaline phosphatase-conjugated rabbit anti-mouse immunoglobulins . The method was applied for characterization of human monoclonals against tetanus toxoid (TT) and for the analysis of variable patterns of clonotypes in IgG subclass-deficient patients . The usefulness of the technique was also demonstrated by comparing the variable specificity and reactivity of different commercial monoclonals against human IgG subclasses . This method is fast, specific, sensitive, uses little material, is simple and reproducible. Ann Hum Genet, 1998 Sep, 62 ( Pt 5), 401 - 9 Construction of a bacterial artificial chromosome (BAC) contig across the minimally deleted region in 13q14.3 in B-cell chronic lymphocytic leukemia; Hawthorn LA et al.; Loss of heterozygosity (LOH) analysis in B-cell chronic lymphocytic leukemia (BCLL) has indicated that a frequent genetic event is loss of alleles from an approximately 500 kb region in 13q14.3, distal to the retinoblastoma gene . We have used DNA markers from this region to isolate and characterize a series of bacterial artificial chromosomes (BACs) which span the region between markers D13S319 and D13S25, which represents the common region of LOH . This entire region appears to be contained within only two minimally overlapping BACs, representing a maximum distance of approximately 350 kb . This BAC contig has been used to position known STS, EST and gene markers within the region . We have also used a modified differential display/RNA fingerprinting procedure designed to isolated transcribed sequences from YACs to isolate two transcribed units from the region which have also been positioned within the contig . The construction of a BAC contig with minimal redundancy provides the ideal resources from which to begin to identify candidate genes related to BCLL. Nihon Kokyuki Gakkai Zasshi, 1999 Jan, 37(1), 10 - 3 {Influence of beclomethasone dipropionate inhalation therapy on respiratory bacterial infection in patients with an acute exacerbation of COPD}; Watanabe Y et al.; The aim of this clinical study was to investigate the influence of beclomethasone dipropionate (BDP) inhalation therapy on respiratory bacterial infections in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) . We studied 30 patients who had been admitted twice, (before and after the beginning BDP inhalation therapy) to our hospital because of an exacerbation of COPD by respiratory tract infection . No differences were observed before and after BDP inhalation therapy in values for PaO2, PaCO2, body temperature, CRP, WBC count, number of admission days, and bacterial culture of sputum on admission . These results suggest that BDP inhalation therapy has little influence on respiratory bacterial infection during exacerbation of COPD. Curr Top Microbiol Immunol, 1999, 241, 155 - 80 Mechanisms of Helicobacter pylori infection: bacterial factors; McGee DJ et al.; Since the discovery of H . pylori in 1982 (MARSHALL 1983; WARREN 1983), research on the mechanisms of virulence of H . pylori has advanced substantially . It is now well established that urease and flagella are virulence factors of H . pylori . Although known for some time to be toxic to epithelial cells in vitro, VacA has only recently been established as a virulence factor . The cag pathogenicity island has also emerged as another virulence contender, although the specific genes involved in virulence are still being determined . Other possible virulence factors, not yet confirmed by gene disruptions, are hapA, katA, sodA, cagA, and iron-regulated genes . As of yet, no adhesins have been confirmed as being important for in vivo survival of H . pylori . With the sequence of the H . pylori genome in hand, it should be possible to more easily determine the role of specific genes in virulence . Genes of immediate interest are the OMPs, which may under go phase and antigenic variation and may represent adhesins . Additionally, virulence-related orthologs and vacA-related genes may provide some interesting findings . Once we define the genes that contribute to H . pylori virulence, we may be able to more easily develop novel therapeutic drugs or vaccines to treat and prevent H . pylori infection. Pacing Clin Electrophysiol, 1999 Feb, 22(2), 393 - 6 Predominant tricuspid stenosis secondary to bacterial endocarditis in a patient with permanent pacemaker and balloon dilatation of the stenosis; Nisanci Y et al.; In a 49-year-old woman with sick sinus syndrome and a permanent VVI pacemaker, severe tricuspid stenosis and its clinical consequences developed 4 years after the attack of endocarditis . Besides the quite unusual occurrence of lead related tricuspid stenosis, successful treatment with balloon dilatation is the unique feature of this case. Genomics, 1999 Mar 15, 56(3), 337 - 9 pPAC-ResQ: A yeast-bacterial shuttle vector for capturing inserts from P1 and PAC clones by recombinogenic targeted cloning; Bhargava J et al.; We have developed a method to capture inserts from P1 and P1 artificial chromosome (PAC) clones into a yeast-bacteria shuttle vector by using recombinogenic targeting . We have engineered a vector, pPAC-ResQ, a derivative of pClasper, which was previously used to capture inserts from yeast artificial chromosome clones . pPAC-ResQ contains DNA fragments flanking the inserts in P1 and PAC vectors as recombinogenic ends . When linearized pPAC-ResQ vector and P1 or PAC DNA are cotransformed into yeast, recombination between the two leads to the transfer of inserts into pPAC-ResQ . pPAC-ResQ clones thus obtained can be further modified in yeast for functional analysis and shuttled to Escherichia coli to produce large quantities of cloned DNA . This approach provides a rapid method to modify P1/PAC clones for functional analysis . Genomics, 1999 Mar 15, 56(3), 237 - 46 Contig assembly of bacterial artificial chromosome clones through multiplexed fluorescence-labeled fingerprinting; Ding Y et al.; A rapid multiplexed fingerprinting method has been developed for bacterial artificial chromosome (BAC) contig assembly . Defined subsets of BAC DNA fragments that result from digestion by three paired restriction endonucleases are labeled with unique fluorescent F-ddATP for each subset . Lists of the labeled fragment size are generated by an ABI 377 DNA sequencer and the GeneScan analysis software and then processed by an assembly program, FPC (Fingerprinted Contigs), to produce contig maps . Data obtained from the multiplexed labeling permit detection of smaller overlaps than is observed when data from a single double-digest are analyzed . The method has been tested on 98 BACs from chromosome 22 regions where large-scale sequencing is under way and also through simulation, using randomly generated BAC clones derived from existing DNA sequence data . In each case, contig assembly results demonstrated the advantages of multiplexed fingerprinting . Arch Biochem Biophys, 1999 Apr 1, 364(1), 42 - 52 Bacterial expression and characterization of the ligand-binding domain of the vitamin D receptor; Strugnell SA et al.; The ligand-binding domain of the rat vitamin D receptor (amino acids 115-423) was expressed as an amino-terminal His-tagged protein in a bacterial expression system and purified over Ni-nitrilotriacetic acid resin and a Mono S column . The purified protein bound its ligand, 1,25-dihydroxyvitamin D3, with high affinity, similar to that of the full-length protein . Saturation of the protein with ligand quenched 90% of the tryptophan fluorescence, consistent with the purified protein being uniformly able to bind ligand . Addition of ligand produced no change in the tryptophan fluorescence lifetime, suggesting static quenching as the mechanism of fluorescence decrease . The near-UV circular dichroism spectrum showed a large increase in signal following the addition of ligand, consistent with a change in the environment of aromatic amino acid side chains . The far-UV circular dichroism spectrum was consistent with a protein of high alpha-helical content . Sedimentation equilibrium experiments demonstrated that the protein formed higher-order complexes, and the distribution of the protein among these complexes was significantly shifted by addition of ligand . Nat Med, 1999 Mar, 5(3), 298 - 302 Neuroprotection by a caspase inhibitor in acute bacterial meningitis; Braun JS et al.; Half of the survivors of bacterial meningitis experience motor deficits, seizures, hearing loss or cognitive impairment, despite adequate bacterial killing by antibiotics . We demonstrate that the broad-spectrum caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl-ketone (z-VAD-fmk) prevented hippocampal neuronal cell death and white blood cell influx into the cerebrospinal fluid compartment in experimental pneumococcal meningitis . Hippocampal neuronal death was due to apoptosis derived from the inflammatory response in the cerebrospinal fluid . Apoptosis was induced in vitro in human neurons by inflamed cerebrospinal fluid and was blocked by z-VAD-fmk . As apoptosis drives neuronal loss in pneumococcal meningitis, caspase inhibitors might provide a new therapeutic option directed specifically at reducing brain damage. Ostomy Wound Manage, 1999 Jan, 45(1A Suppl), 109S - 118S; quiz 119S-120S Bacterial colonization/infection and the surgical management of pressure ulcers; Brown DL et al.; The purpose of this paper is to review the current recommendations and guidelines for the care and treatment of pressure ulcers with specific reference to the control of infection within these wounds and surgical management . After reviewing the literature published between May 1993 and April 1998, it is our contention that no significant changes in the clinical management of this problem are warranted . This may signal the need for further study in this area . Recommendations for the optimal care of clean and infected pressure ulcers are included. Biochem J, 1999 Apr 1, 339 ( Pt 1), 33 - 6 Position-independent and copy-number-related expression of a goat bacterial artificial chromosome alpha-lactalbumin gene in transgenic mice; Stinnakre MG et al.; A bacterial artificial chromosome goat insert comprising the alpha-lactalbumin-encoding transcription unit with approximately 150 and 10 kb of 5'- and 3'-flanking sequences, respectively, was micro-injected into mouse eggs . In six out of seven transgenic lines, the level of mammary tissue- and stage-specific expression was position-independent and copy-number-dependent . The exogenous alpha-lactalbumin yield, about 0.8 mg/ml of milk per copy, compared favourably with the alpha-lactalbumin content of mouse and goat milks, about 0.8 and >1 mg/ml, respectively . This suggests that the insert contains most if not all of the cis-acting elements involved in the full and specific expression of the goat alpha-lactalbumin gene and opens up opportunities to use this vector to target expression of foreign genes in the lactating mammary gland of transgenic animals . The transgene was silent in the seventh line for an unknown reason. Infect Immun, 1999 Apr, 67(4), 1539 - 46 Febrile-range temperature modifies early systemic tumor necrosis factor alpha expression in mice challenged with bacterial endotoxin; Jiang Q et al.; Fever improves survival in acute infections, but the effects of increased core temperature on host defenses are poorly understood . Tumor necrosis factor alpha (TNF-alpha) is an early activator of host defenses and a major endogenous pyrogen . TNF-alpha expression is essential for survival in bacterial infections but, if disregulated, can cause tissue injury . In this study, we show that passively increasing core temperature in mice from the basal (36.5 to 37.5 degrees C) to the febrile (39.5 to 40 degrees C) range modifies systemic TNF-alpha expression in response to bacterial endotoxin (lipopolysaccharide) . The early TNF-alpha secretion rate is enhanced, but the duration of maximal TNF-alpha production is shortened . We identified Kupffer cells as the predominant source of the excess TNF-alpha production in the warmer animals . The enhanced early TNF-alpha production observed at the higher temperature in vivo could not be demonstrated in isolated Kupffer cells or in precision-cut liver slices in vitro, indicating the participation of indirect pathways . Therefore, expression of the endogenous pyrogen TNF-alpha is regulated by increments in core temperature during fever, generating an enhanced early, self-limited TNF-alpha pulse. Chest, 1999 Mar, 115(3), 829 - 35 Bacterial endotoxin is an active component of cigarette smoke; Hasday JD et al.; BACKGROUND: Chronic bronchitis in cigarette smokers shares many clinical and histologic features with environmental lung diseases attributed to bacterial endotoxin (lipopolysaccharide {LPS}) inhalation . Experimental LPS inhalation mimics many of the acute effects of cigarette smoke in the lower airway . Therefore, we reasoned that LPS may be a biologically active component of cigarette smoke . DESIGN: The Limulus amebocyte lysate (LAL) assay was used to measure LPS in the tobacco and filter tip components of unsmoked 1R4F experimental cigarettes and commercially available "light" cigarettes, as well as in mainstream (MS) and sidestream (SS) smoke particles generated with an automated smoking machine and collected on ventilator mainflow filters . SETTING AND PARTICIPANTS: Blood LPS activity and plasma cytokine concentrations were measured in groups of healthy smokers and nonsmokers who reported to the walk-in clinic at the Baltimore VA Medical Center for unrelated complaints . MEASUREMENTS: Blood LPS levels were measured by LAL assay and plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), soluble TNF receptors I and II (sTNFR I and sTNFR II) were measured by enzyme-linked immunosorbent assay . RESULTS: Bioactive LPS was detected in both the tobacco portion (1R4F, 17.8+/-1.0 microg/cigarette; light, 26.8+/-7.3 microg/cigarette {mean+/-SE}) and filter tips (1R4F, 0.67+/-0.55 microg/cigarette; light, 0.70+/-0.39 microg/cigarette) of cigarettes . Bioactive LPS was also detected in both MS (1R4F, 120+/-64 ng/cigarette; light: 45.3+/-16 ng/cigarette) and SS smoke (1R4F, 18+/-1.5 ng/cigarette; light: 75+/-49 ng/cigarette) . Although systemic absorption of inhaled LPS may occur, we failed to detect any differences between nonsmokers and smokers in median blood LPS levels (median values, 66.75 and 72.1 pg/mL, respectively; p = 0.55) or plasma concentrations of TNF-alpha (0 vs 0 pg/mL, respectively; p = 0.71), sTNFR I(1,469 vs 1,576 pg/mL, respectively), sTNFR II (2,011 vs 3,110 pg/mL, respectively), or IL-6 (8.8 vs 0 pg/mL, respectively; p = 0.20) . CONCLUSIONS: Smoking one pack of cigarettes per day delivers a dose of respirable LPS that is comparable to the levels of LPS associated with adverse health effects in cotton textile workers . Thus, we suggest that the bioactive LPS in cigarette smoke may contribute to the pathogenesis of chronic bronchitis that develops in susceptible cigarette smokers. FEMS Microbiol Lett, 1999 Feb 15, 171(2), 73 - 9 Bacterial alpha-glucan phosphorylases; Schinzel R et al.; Although glycogen and other alpha-1,4-D-glucan storage polysaccharides are present in many bacteria, only few glucan phosphorylases from bacteria have been identified and characterised on the protein or gene level . All bacterial phosphorylases follow the same catalytic mechanisms as their plant and vertebrate counterparts, but differ considerably in terms of their substrate specificity and regulation . The catalytic domains are highly conserved while the regulatory sites are only poorly conserved . The degree of conservation between bacterial and mammalian phosphorylases is comparable to that of other non-mammalian and mammalian alpha-glucan phosphorylases . Only for maltodextrin phosphorylase from E . coli the physiological role of the enzyme in the utilisation of maltodextrins is known in detail; that of all other phosphorylases remains still unclear . Roles in regulation of endogenous glycogen metabolism in periods of starvation, and sporulation, stress response or quick adaptation to changing environments are imaginable. J Virol, 1999 Apr, 73(4), 2650 - 7 Bacterial lipopolysaccharide inhibits dengue virus infection of primary human monocytes/macrophages by blockade of virus entry via a CD14-dependent mechanism; Chen YC et al.; Monocytes/macrophages (MO/Mphi) are the major target cells for both dengue virus (DV) and bacterial lipopolysaccharide (LPS), and the aim of this study was to define their interactions . We had found that LPS markedly suppressed DV infection of primary human MO/Mphi when it was added to cultures prior to or together with, but not after, viral adsorption . The inhibitory effect of LPS was direct and specific and was not mediated by LPS-induced secretion of cytokines and chemokines such as tumor necrosis factor alpha, interleukin-1beta (IL-1beta), IL-6, IL-8, IL-12, alpha interferon, MIP-1alpha, and RANTES . In fact, productive DV infection was not blocked but was just postponed by LPS, with a time lag equal to one viral replication cycle . Time course studies demonstrated that LPS was only effective in suppressing DV infection of MO/Mphi that had not been previously exposed to the virus . At various time points after viral adsorption, the level of unbound viruses that remained free in the culture supernatants of LPS-pretreated cultures was much higher than that of untreated controls . These observations suggest that the LPS-induced suppression of DV replication was at the level of virus attachment and/or entry . Blockade of the major LPS receptor, CD14, with monoclonal antibodies MY4 or MoS39 failed to inhibit DV infection but could totally abrogate the inhibitory effect of LPS . Moreover, human serum could significantly enhance the LPS-induced DV suppression in a CD14-dependent manner, indicating that the "binding" of LPS to CD14 was critical for the induction of virus inhibition . Taken together, our results suggest that LPS blocked DV entry into human MO/Mphi via its receptor CD14 and that a CD14-associated cell surface structure may be essential for the initiation of a DV infection. J Immunol, 1999 Mar 1, 162(5), 2931 - 8 Bacterial lipopolysaccharide causes rapid shedding, followed by inhibition of mRNA expression, of the IL-1 type II receptor, with concomitant up-regulation of the type I receptor and induction of incompletely spliced transcripts; Penton-Rol G et al.; The IL-1 type I receptor (IL-1RI) is part of a signaling complex together with the IL-1R accessory protein, whereas available information is consistent with a "decoy" model of function for the IL-1 type II receptor (IL-1RII) . The present study was designed to investigate the effect of bacterial LPS on IL-1R in human monocytes . LPS causes rapid release of the IL-1RII, an effect blocked by a metalloprotease inhibitor . Subsequently, LPS-treated monocytes showed a drastic reduction of IL-1RII mRNA . In contrast, LPS induced IL-1RI and, to a lesser extent, IL-1AcP expression . LPS-induced augmented expression of the canonical 5-kb IL-1RI mRNA was accompanied by the appearance of 2.4-kb IL-1RI transcripts . The use of probes representative of different regions of the IL-1RI mRNA, as well as cDNA cloning, revealed that the 2.4-kb inducible band includes incompletely spliced, polyadenylated transcripts potentially encoding truncated versions of the receptor . The observation that the prototypic proinflammatory molecule LPS has divergent effects on IL-1Rs, with inhibition of IL-1RII and stimulation of IL-1RI and IL-1R accessory protein, is consistent with the view that these molecules subserve opposite functions in the pathophysiology of the IL-1 system . The rapid shedding of IL-1RII by monocytes early in recruitment may serve to buffer the systemic action of IL-1 leaking from sites of inflammation . This early event, followed by prolonged inhibition of IL-1RII expression and up-regulation of IL-1RI, may render monocytes more responsive to IL-1 at sites of inflammation. J Protein Chem, 1999 Jan, 18(1), 127 - 36 Properties of soluble fusions between mammalian aspartic proteinases and bacterial maltose-binding protein; Sachdev D et al.; The mammalian aspartic proteinases procathepsin D and pepsinogen form insoluble inclusion bodies when expressed in bacteria . They become soluble but nonnative when synthesized as fusions to the carboxy terminus of E . coli maltose-binding protein (MBP) . Since these nonnative states of the two aspartic proteinases showed no tendency to form insoluble aggregates, their biophysical properties were analyzed . The MBP portions were properly folded as shown by binding to amylose, but the aspartic proteinase moieties failed to bind pepstatin and lacked enzymatic activity, indicating that they were not correctly folded . When treated with proteinase K, only the MBP portion of the fusions was resistant to proteolysis . The fusion between MBP and cathepsin D had increased hydrophobic surface exposure compared to the two unfused partners, as determined by bis-ANS binding . Ultracentrifugal sedimentation analysis of MBP-procathepsin D and MBP-pepsinogen revealed species with very large and heterogeneous sedimentation values . Refolding of the fusions from 8 M urea generated proteins no larger than dimers . Refolded MBP-pepsinogen was proteolytically active, while only a few percent of renatured MBP-procathepsin D was obtained . The results suggest that MBP-aspartic proteinase fusions can provide a source of soluble but nonnative folding states of the mammalian polypeptides in the absence of aggregation. Br J Neurosurg, 1998 Oct, 12(5), 440 - 4 Embolic bacterial aneurysm of the basilar artery: case report; Roberts G et al.; A patient with basilar artery rupture caused by a septic embolus originating from a mitral valve vegetation is reported . The pathogenesis, investigation and management of infected cerebral aneurysms are reviewed. Trends Microbiol, 1999 Jan, 7(1), 16 - 22 Throwing the switch in bacterial chemotaxis; Silversmith RE et al.; In Escherichia coli chemotaxis, the switch from counterclockwise to clockwise rotation of the flagella occurs as a result of binding of the phosphorylated CheY protein to the base of the flagellum . Analysis of CheY variants has provided a picture of the surface of CheY that undergoes conformational shifts, as a result of phosphorylation, to interact directly with the flagellum . Whether phospho-CheY binding and flagellar switching are sequential steps or can occur in a concerted fashion has yet to be determined. J Surg Res, 1999 Mar, 82(1), 106 - 11 Glycyl-glutamine-enriched long-term total parenteral nutrition attenuates bacterial translocation following small bowel transplantation in the pig; Li YS et al.; BACKGROUND: Improvements in immunosuppression, operative procedure, and posttransplant management have made clinical small bowel transplantation (SBT) feasible . Ischemia and reperfusion injury, total parenteral nutrition (TPN), and devoidment of enteral feeding lead to graft atrophy, gut barrier dysfunction, and bacterial translocation . Glutamine (Gln) is the principal fuel for the enterocyte . The influence of Gln dipeptide-supplemented TPN, especially long-term TPN, on intestinal graft permeability and bacterial translocation is not clear following SBT in the large animal model . Therefore, we studied the effect of glutamine dipeptide, glycyl-glutamine (Gly-Gln), on bacterial translocation following SBT in the pig, which has a physiology similar to humans . MATERIALS AND METHODS: The outbred pigs underwent segmental small bowel autotransplantation and were divided into two groups . In the STPN group (n = 5), the animal received standard TPN devoid of Gly-Gln for 28 days . In the GTPN group (n = 5), the animal received isonitrogenous (0.3 g/kg.day) and isocaloric (33 kcal/kg.day) TPN solution with 2% Gly-Gln for 28 days . RESULTS: At the end of the experiment, Gly-Gln-enriched TPN could maintain the plasma Gln level, graft mucosal Gln and protein concentrations, and skeletal muscle Gln and protein concentrations . Gly-Gln-enriched TPN significantly decreased the bacterial number of mesenteric lymph nodes in the liver and spleen and intestinal permeability to 99mTc-DTPA . There were no significant differences in body weight gain . CONCLUSIONS: The Gly-Gln-enriched long-term TPN may maintain the plasma Gln level, mucosal and muscle Gln, and protein concentrations and attenuate the intestinal permeability to 99mTc-DTPA and bacterial translocation following small bowel transplantation in the pig . Curr Opin Microbiol, 1998 Oct, 1(5), 509 - 15 Bacterial enzymatic resistance: beta-lactamases and aminoglycoside-modifying enzymes; Bush K et al.; Numerous novel beta-lactamases and aminoglycoside-modifying enzymes with altered substrate profiles continue to be identified . Plasmid-mediated transmission of many of these enzymes readily occurs due to inclusion of the encoding genes in mobile gene cassettes . Recent crystallographic determinations of the structures of metallo-beta-lactamases and aminoglycoside-modifying enzymes provide the opportunity for the rational design of inhibitors. Curr Opin Microbiol, 1998 Oct, 1(5), 572 - 9 Mycoplasma pneumoniae and Mycoplasma genitalium: a comparison of two closely related bacterial species; Herrmann R et al.; The rapid progress in sequencing large quantities of DNA will provide an increasing number of complete genome sequences of closely related bacterial species as well as of pairs of isolates from the same species with different features, such as a pathogenic and an apathogenic representative . This opens the way to apply subtractive comparative analysis as a tool to select from the large pool of all bacterial genes a relatively small set of genes that can be correlated with the expression of a certain phenotype . These selected genes can then be the target for further functional analyses. J Pediatr Gastroenterol Nutr, 1999 Mar, 28(3), 296 - 300 Helicobacter pylori and nonulcer dyspepsia in childhood: clinical pattern, diagnostic techniques, and bacterial strains; Rutigliano V et al.; BACKGROUND: This is a report of the results of a multicenter study performed in children with dyspepsia from five pediatric centers in Puglia, a region in southern Italy . In the study, clinical features of Helicobacter pylori infection, the reliability of diagnostic techniques, and the involvement of bacterial strains were examined . METHODS: Fifty-three outpatients with dyspepsia enrolled in our study and compiled a diary recording clinical symptoms in patients before they underwent the following diagnostic techniques: endoscopy, biopsy for histologic analysis, rapid urease test, 13C urea breath test, serology specific for immunoglobulin (Ig)G and anti-CagA and VacA . RESULTS: H . pylori showed a prevalence of 30.2% (n = 16) . Histologic positivity was seen in all patients at the antral level (H . pylori-associated chronic gastritis) . In the gastric body, bacterial chronic active gastritis was present only in six patients (H . pylori-associated chronic pangastritis) . Clinical evaluation showed a significant difference in favor of subjects positive for H . pylori only for epigastric burning and/or pain (p < 0.001) . The comparison of results of diagnostic tests, using histology as the gold standard, showed sensitivity and specificity of more than 93% for 13C urea breath test and more than 85% for rapid urease test and serology . Anti-CagA antibodies were found in 64.3% and anti-VacA antibodies in 42.8% of H . pylori-positive patients . CONCLUSIONS: H . pylori prevalence in children with dyspepsia from the geographic area studied is comparable with that found in other developed countries . Approximately 50% of the studied patients were infected by cytotoxic strains . The urea breath test was the most reliable noninvasive diagnostic tool and is suitable for routine use, although endoscopy with histologic assessment remains the definitive investigation and is particularly important in patients with positive serology for CagA and VacA . Finally, the frequency of aggressive strains in our region seems to affect the clinical pattern; this emphasizes the importance of definitive diagnosis in children and offers a new role for serology. Microbiol Mol Biol Rev, 1999 Mar, 63(1), 161 - 73 Protein targeting to the bacterial cytoplasmic membrane; Fekkes P et al.; Proteins that perform their activity within the cytoplasmic membrane or outside this cell boundary must be targeted to the translocation site prior to their insertion and/or translocation . In bacteria, several targeting routes are known; the SecB- and the signal recognition particle-dependent pathways are the best characterized . Recently, evidence for the existence of a third major route, the twin-Arg pathway, was gathered . Proteins that use either one of these three different pathways possess special features that enable their specific interaction with the components of the targeting routes . Such targeting information is often contained in an N-terminal extension, the signal sequence, but can also be found within the mature domain of the targeted protein . Once the nascent chain starts to emerge from the ribosome, competition for the protein between different targeting factors begins . After recognition and binding, the targeting factor delivers the protein to the translocation sites at the cytoplasmic membrane . Only by means of a specific interaction between the targeting component and its receptor is the cargo released for further processing and translocation . This mechanism ensures the high-fidelity targeting of premembrane and membrane proteins to the translocation site. Clin Diagn Lab Immunol, 1999 Mar, 6(2), 247 - 53 Predictive value of CD19 measurements for bacterial infections in children infected with human immunodeficiency virus; Betensky RA et al.; We investigated the predictive value of CD19 cell percentages (CD19%) for times to bacterial infections, using data from six pediatric AIDS Clinical Trials Group protocols and adjusting for other potentially prognostic variables, such as CD4%, CD8%, immunoglobulin (IgA) level, lymphocyte count, prior infections, prior zidovudine treatment, and age . In addition, we explored the combined effects of CD19% and IgG level in predicting time to infection . We found that a low CD19% is associated with a nonsignificant 1.2-fold increase in hazard of bacterial infection (95% confidence interval: 0.97, 1.49) . In contrast, a high IgG level is associated with a nonsignificant 0.87-fold decrease in hazard of infection (95% confidence interval: 0.68, 1.12) . CD4% was more prognostic of time to bacterial infection than CD19% or IgG level . Low CD19% and high IgG levels together lead to a significant (P < 0 . 01) 0.50-fold decrease in hazard (95% confidence interval: 0.35, 0 . 73) relative to low CD19% and low IgG levels . Similarly, in a model involving assay result changes (from baseline to 6 months) as well as baseline values, the effect of CD19% by itself is reversed from its effect in conjunction with IgG . In this model, CD19% that are increasing and high are associated with decreases in hazard of infection (P < 0.01), while increasing CD19% and increasing IgG levels are associated with significant (at the P = 0.01 level) fourfold increases in hazard of infection relative to stable CD19% and decreasing, stable, or increasing IgG levels . Our data suggest that CD19%, in conjunction with IgG level, provides a useful prognostic tool for bacterial infections . It is highly likely that T-helper function impacts on B-cell function; thus, inclusion of CD4% in such analyses may greatly enhance the assessment of risk for bacterial infection. Curr Opin Microbiol, 1998 Apr, 1(2), 210 - 5 The regulation of bacterial cell division: a time and place for it; Lutkenhaus J; Temporal and spatial regulation of cell division assures that each daughter cell receives a copy of the chromosome . Within the past year, the application of fluorescence microscopy to the cell biology of bacteria has revealed an increasing number of proteins that are localized within the bacterial cell to carry out DNA segregation and cell division . The localization of these proteins implies the existence of positional information in the cell, but how this information is established is unknown. Curr Opin Microbiol, 1998 Apr, 1(2), 248 - 53 Bacterial solute uptake and efflux systems; Lolkema JS et al.; The recent discovery of binding protein dependent secondary transporters and the ever-growing family of membrane potential generating secondary transporters emphasize the diversity of transport systems in both the mechanistical and physiological sense . The vast amount of data on the lactose permease is now beginning to crystallize in a model that relates functional events to structural changes of the protein . Evidence has been presented that multidrug transporters pick up their substrates from the membrane, and the binding of a number of substrates to the binding-protein components of ATP-driven transporters is now understood in detail. Curr Opin Microbiol, 1998 Apr, 1(2), 145 - 51 Some repressors of bacterial transcription; Muller-Hill B; For a long time, repression of transcription in Escherichia coli was thought to be generally caused by one repressor binding to one operator . Recent work has indicated the frequent presence of auxiliary operators and helper proteins . The recent solution of the X-ray structures of Lac and Pur repressors were breakthroughs; yet, it has become painfully clear that important aspects of repression are still not understood. Curr Opin Microbiol, 1998 Feb, 1(1), 96 - 102 Helicobacter pylori: molecular evolution of a bacterial quasi-species; Covacci A et al.; Helicobacter pylori persists chronically within individuals and as they spread the mutating bacteria migrate with them . The continuous selection and microevolution generates a population of closely related but different bacteria that behave like a quasi-species . Within this heterogeneity, H . pylori strains fall into distinct types, into the virulent (type I) and less virulent (type II) strains, based on the presence of a pathogenicity island (cag) that encodes a specialized secretion machinery . We propose that during chronic infection a dynamic equilibrium between bacteria expressing a disparate degree of virulence is established, and that diverse forms prevail at different times. J Mol Biol, 1999 Mar 12, 286(5), 1471 - 85 An irregular beta-bulge common to a group of bacterial RNases is an important determinant of stability and function in barnase; Axe DD et al.; Single amino acid residue substitutions rarely destroy the structural integrity of proteins . Substitution of glycine residues, however, is among the few sorts of alterations that can have such an effect . Here, we seek to understand what accounts for the extreme functional impairment of the bacterial ribonuclease barnase upon substitution of Gly52 or Gly53 . We find that inactivation is caused by overall disruption of the folded state that manifests itself in three ways: (1) dramatically reduced stability (by 5.2 to 8.4 kcal mol-1 for mutants showing inactivation in vivo); (2) progressive loss of folded-state activity with increasing temperature, indicating a less well formed fold; and (3) substantial proteolytic degradation of mutant enzymes in vivo . Examination of two deletion mutants, missing either Gly53 or Asp54, shows that the irregular beta-bulge formed by these two residues is of vital importance to the structural integrity of barnase . The parallel behaviour of mutants carrying replacements of either of the two glycine residues therefore appears to arise from a common mechanism: disruption of local structure at the beta-bulge . The importance of this structural element to the function of barnase raises the question of whether it may be present in other RNases . The Streptomyces enzymes RNase Sa and RNase St differ considerably from barnase in both sequence and structure, yet both show significant sequence similarity to barnase over a region beginning at Gly53 . Structural comparison indicates that the Streptomyces enzymes do have the barnase-like irregular beta-bulge, making this an important characteristic feature of a group of bacterial ribonucleases . The sensitivity of this feature demonstrates that detailed aspects of local structure may have a major role in determining the overall structural and functional properties of an enzyme, even where no explanation for this role is readily apparent . If this is a general characteristic of the structure-function relationship, it may pose a formidable obstacle to the de novo design of new enzymes . J Mol Biol, 1999 Mar 12, 286(5), 1365 - 78 A three-way junction and constituent stem-loops as the stimulator for programmed -1 frameshifting in bacterial insertion sequence IS911; Rettberg CC et al.; Several signals are required for the programmed frameshifting in translation of IS911 mRNA . These include a Shine Dalgarno (SD)-like sequence, a slippery sequence of six adenine residues and a guanine residue (A6G) and a 3' secondary structure . The structure of the mRNA containing these elements was investigated using chemical and enzymatic probing . The probing data show that the 3' structure is a three-way junction of stems . The function of the three-way junction was investigated by mutagenesis . Disrupting the stability of the structure greatly affects frameshifting and transposition levels as tested by separate in vivo assays . Structural probing and thermal melting profiles indicate that the disrupted three-way junctions have altered structures . J Mol Biol, 1999 Mar 12, 286(5), 1275 - 84 Inversion of thermosensing property of the bacterial receptor Tar by mutations in the second transmembrane region; Nishiyama S et al.; The aspartate chemoreceptor Tar of Escherichia coli serves as a warm sensor that produces attractant and repellent signals upon increases and decreases in temperature, respectively . However, increased levels of methylation of the cytoplasmic domain of Tar resulting from aspartate binding convert Tar to a cold sensor with the opposite signaling behavior . Detailed analyses of the methylation sites, which are located in two separate alpha-helices (MH1 and MH2), have suggested that intra- and/or intersubunit interactions of MH1 and MH2 play a critical role in thermosensing . These interactions may be influenced by binding of aspartate, which could trigger some displacement of MH1 through the second transmembrane region (TM2) . As an initial step toward understanding the role of TM2 in thermosensing, we have examined the thermosensing properties of 43 mutant Tar receptors with randomized TM2 sequences (residues 190-210) . Among them, we identified one mutant receptor (Tar-I2) that functioned as a cold sensor in the absence of aspartate . This is the first example of attractant-independent inversion of thermosensing in Tar . Further analyses identified the minimal essential divergence from the wild-type Tar sequence (Q191V-W192R-Q193C) required for the inverted response . Thus, displacements of TM2 seem to influence the thermosensing function of Tar . Eur J Immunol, 1999 Feb, 29(2), 499 - 511 Distinct regulation of HLA class II and class I cell surface expression in the THP-1 macrophage cell line after bacterial phagocytosis; De Lerma Barbaro A et al.; Expression of HLA and CD1b molecules was investigated in the THP-1 macrophage cell line within 2 weeks following phagocytosis of mycobacteria or Escherichia coli . During the first 2-3 days, cell surface expression of HLA class II and CD1b was drastically down-modulated, whereas HLA class I expression was up-modulated . In the following days both HLA class II and CD1b expression first returned to normal, then increased and finally returned to normal with kinetics similar to that observed for the steadily increased HLA class I . The initial down-modulation of HLA class II and CD1b cell surface antigens was absolutely dependent on phagocytosis of bacteria . Further studies indicated that initial HLA class II cell surface down-modulation (1) was not due to reduced transcription or biosynthesis of mature HLA class II heterodimers, (2) was only partially, if at all, rescued by treatment with IFN-gamma, although both mRNA and corresponding intracellular proteins increased up to sixfold with respect to untreated cells, and (3) resulted in failure of THP-1 cells to process and present mycobacterial antigens to HLA-DR-restricted antigen-specific T cell lines . The existence of a transient block of transport of mature HLA class II heterodimers to the cell surface in the first days after phagocytosis of bacteria may have negative and positive consequences: it decreases APC function early but it may increase it later by favoring optimal loading of bacterial antigens in cellular compartments at high concentration of antigen-presenting molecules. Appl Environ Microbiol, 1999 Mar, 65(3), 1045 - 9 Polynucleotide probes that target a hypervariable region of 16S rRNA genes to identify bacterial isolates corresponding to bands of community fingerprints; Heuer H et al.; Temperature gradient gel electrophoresis (TGGE) is well suited for fingerprinting bacterial communities by separating PCR-amplified fragments of 16S rRNA genes (16S ribosomal DNA {rDNA}) . A strategy was developed and was generally applicable for linking 16S rDNA from community fingerprints to pure culture isolates from the same habitat . For this, digoxigenin-labeled polynucleotide probes were generated by PCR, using bands excised from TGGE community fingerprints as a template, and applied in hybridizations with dot blotted 16S rDNA amplified from bacterial isolates . Within 16S rDNA, the hypervariable V6 region, corresponding to positions 984 to 1047 (Escherichia coli 16S rDNA sequence), which is a subset of the region used for TGGE (positions 968 to 1401), best met the criteria of high phylogenetic variability, required for sufficient probe specificity, and closely flanking conserved priming sites for amplification . Removal of flanking conserved bases was necessary to enable the differentiation of closely related species . This was achieved by 5' exonuclease digestion, terminated by phosphorothioate bonds which were synthesized into the primers . The remaining complementary strand was removed by single-strand-specific digestion . Standard hybridization with truncated probes allowed differentiation of bacteria which differed by only two bases within the probe target site and 1.2% within the complete 16S rDNA . However, a truncated probe, derived from an excised TGGE band of a rhizosphere community, hybridized with three phylogenetically related isolates with identical V6 sequences . Only one of the isolates comigrated with the excised band in TGGE, which was shown to be due to identical sequences, demonstrating the utility of a combined TGGE and V6 probe approach. J Struct Biol, 1998 Dec 15, 124(2-3), 189 - 200 Structural analysis of bacterial chemotaxis proteins: components of a dynamic signaling system; Djordjevic S et al.; Most motile bacteria are capable of directing their movement in response to chemical gradients, a behavior known as chemotaxis . The signal transduction system that mediates chemotaxis in enteric bacteria consists of a set of six cytoplasmic proteins that couple stimuli sensed by a family of transmembrane receptors to behavioral responses generated by the flagellar motors . Signal transduction occurs via a phosphotransfer pathway involving a histidine protein kinase, CheA, and a response regulator protein, CheY, that in its phosphorylated state, modulates the direction of flagellar rotation . Two auxiliary proteins, CheW and CheZ, and two receptor modification enzymes, methylesterase CheB and methyltransferase CheR, influence the flux of phosphoryl groups within this central pathway . This paper focuses on structural characteristics of the four signaling proteins (CheA, CheY, CheB, and CheR) for which NMR or x-ray crystal structures have been determined . The proteins are examined with respect to their signaling activities that involve reversible protein modifications and transient assembly of macromolecular complexes . A variety of data suggest conformational flexibility of these proteins, a feature consistent with their multiple roles in a dynamic signaling pathway . J Struct Biol, 1998 Dec 15, 124(2-3), 123 - 8 Bacterial helicases; Egelman EH; Helicases are proteins that use the energy of ATP hydrolysis to open double-stranded DNA, RNA, or RNA-DNA hybrids into two single strands . Based upon sequence analysis, at least 12 helicases exist in Escherichia coli . We know that these proteins play important roles in DNA replication, recombination, repair, and transcription, as well as in RNA processing . Recent crystallographic studies have revealed a highly conserved catalytic core in the helicases, shared with the RecA protein and the F1-ATPase . However, evidence suggests that the functional divergence may be large . J Struct Biol, 1998 Dec 15, 124(2-3), 104 - 14 A structural feature in the central channel of the bacterial flagellar FliF ring complex is implicated in type III protein export; Suzuki H et al.; The FliF ring complex, which consists of the M-S ring and a proximal portion of the rod of the flagellar basal body, is the base structure for the bacterial flagellar assembly . The FliF ring is also thought to be part of the export apparatus for flagellar proteins from its amino acid sequence homology to proteins involved in type III protein export systems . We established a new purification procedure for the FliF ring particles and carried out electron microscopic image analyses in their two distinct forms: well-dispersed single particles in the presence of salt and ordered monolayer arrays of hexagonal packing formed in the absence of salt . In both cases, the axial projection maps showed a common feature, a pair of concentric rings: the inner ring corresponds to the proximal rod; the outer ring represents the thick, edge portion of the M-S ring . However, the central channel of the FliF ring, the putative pathway for the flagellar protein export, appeared to show distinct structural features in the two forms . This suggests that a domain of FliF partially occupies the central channel to be involved in the export and gate mechanism, and the domain changes its conformation depending on the ionic strength . Protein Expr Purif, 1999 Mar, 15(2), 162 - 70 Refolding, purification, and characterization of a loop deletion mutant of human Bcl-2 from bacterial inclusion bodies; Anderson M et al.; This report describes the cloning of recombinant human Bcl-2, in which the putative disordered loop region has been replaced with a flexible linker and the hydrophobic C-terminus has been replaced with a 6xHis tag (Bcl-2(6-32)-AAAA-Bcl-2(86-206)-HHHHHH, abbreviation rhBcl-2; amino acid numbering excludes the initiating methionine) . This protein was expressed in Escherichia coli where it accumulated in insoluble form in inclusion bodies . After lysis the washed inclusion bodies were solubilized and an l-arginine assisted protein refolding route was employed to obtain biologically active protein . rhBcl-2 was purified further by nickel chelate chromatography to give protein of >95% purity, with an overall yield of 5 mg per g of E . coli cell paste . Edman sequencing showed that approximately 90% of the rhBcl-2 retained the initiating methionine residue . Analytical size exclusion chromatography suggested that the refolded and purified rhBcl-2 was monomeric in nondenaturing solution . Purified protein had an affinity for a Bax BH3 domain peptide comparable to that for in vivo folded recombinant human Bcl-2 and suppressed caspase activation in a cell-free assay for apoptosis . 1H NMR spectroscopy of rhBcl-2, both free and complexed with the Bax BH3 domain peptide, provided further evidence for the structural and functional integrity of the refolded protein . These findings parallel and extend those of Muchmore et al., who found that a loop deletion mutant of human Bcl-XL retained anti-apoptotic function . Pediatr Infect Dis J, 1999 Feb, 18(2), 157 - 63 Evaluating children with respiratory tract infections: the role of immunization with bacterial polysaccharide vaccine; Wasserman RL et al.; Antibody deficiency syndromes are an important cause of recurrent infections in children . Today it is possible to perform a complete evaluation of antibody-mediated immunity leading to a definitive diagnosis of either normal or abnormal immunity in most patients . However, the interpretation of the results of IgG subclass determinations and specific antibody responses is still being defined . At this time our recommendation is that patients who meet the criteria for an evaluation of antibody-mediated immunity be referred to subspecialists trained in this evaluation until better criteria for normal have been developed . The possibility that protective amounts of antibodies against pneumococcal serotypes may develop only transiently must be considered in patients with recurrent infections after initial improvement after immunization, especially if IgG2 subclass deficiency is also present . In the future it may be possible to use a faster and more economical approach to evaluate patients with recurrent infections by immunization with pneumococcal vaccine and then measuring IgM, IgG and IgA along with postimmunization specific antipneumococcal antibody titers 4 to 6 weeks later . For this approach to become feasible, further studies comparing the information obtained from the evaluation of pre- and postimmunization antibody concentrations with that obtained from the evaluation of postimmunization concentrations alone are needed. J Antibiot (Tokyo), 1998 Dec, 51(12), 1099 - 104 Selective inhibition of the bacterial peptidoglycan biosynthesis by the new types of liposidomycins; Kimura K et al.; We examined the inhibitory activity against bacterial peptidoglycan biosynthesis, mammalian glycoprotein biosynthesis and growth of BALB/3T3 cells of four different types of liposidomycins which have the structure with or without sulfate and/or 3-methylglutaric acid moieties . Liposidomycins inhibited peptidoglycan biosynthesis about 30 to 500 times more effectively than tunicamycin, whereas liposidomycins inhibited mammalian glycoprotein biosynthesis about 30 to 300 times less effectively than tunicamycin . When the cytotoxic effect of liposidomycins and tunicamycin on the growth of mammalian cells were compared, liposidomycins did not show toxicity against BALB/3T3 cell at 25 microg/ml, though tunicamycin inhibited cell growth by 50% at 0.05 microg/ml . On the basis of these results, it is concluded that liposidomycins are selective antibiotics showing highly specific inhibition toward bacterial peptidoglycan biosynthesis. Nucleic Acids Res, 1999 Mar 15, 27(6), 1555 - 7 Rapid modification of bacterial artificial chromosomes by ET-recombination; Muyrers JP et al.; We present a method to modify bacterial artificial chromosomes (BACs) resident in their host strain . The method is based on homologous recombination by ET-cloning . We have successfully modified BACs at two distinct loci by recombination with a PCR product containing homology arms of 50 nt . The procedure we describe here is rapid, was found to work with high efficiency and should be applicable to any BAC modification desired. Am J Surg, 1999 Jan, 177(1), 38 - 41 Biliary bacterial infection decreased the secretion of bile acids and bilirubin into bile; Nishida T et al.; BACKGROUND: Bacterial cholangitis is frequently associated with serious complications . METHODS: The plasma disappearance rates and the biliary output of bile acids and bilirubin after percutaneous transhepatic biliary drainage (PTBD) were examined in 29 patients with extrahepatic biliary obstruction . RESULTS: Twenty-nine patients were divided into the bacteria-minus (n = 17) and bacteria-plus (n = 12) groups . Decreases in the plasma bile acid and bilirubin levels of the bacteria-minus group (t1/2 = 0.38 and 3.8 days for bile acids and bilirubin, respectively) were faster than those of the bacteria-plus group (t1/2 = 1.7 and 7.5 days) . The bile flow rate was significantly increased in the bacteria-plus group compared with the bacteria-minus group . The calculated values of bilirubin and bile acid in the bile were higher in the bacteria-minus group than in the bacteria-plus group . CONCLUSIONS: Bacterial colonization in the bile stimulates bile duct cells to increase bile volume and inhibits the hepatocyte transport activity of bile acids and bilirubin. Trends Microbiol, 1998 Dec, 6(12), 496 - 500 Bacterial DNA as immune cell activator; Lipford GB et al.; Pattern recognition receptors of the innate and adaptive immune systems apparently recognize unmethylated CpG motifs of bacterial DNA . Cells of the innate immune system are activated directly by CpG motifs, and the resulting response dictates a Th1 bias to the developing adaptive immune response . Interestingly, antigen receptor occupancy of cells of the adaptive immune system augments their responsiveness to CpG motifs, suggesting that co-stimulatory mechanisms are operative. Am J Respir Cell Mol Biol, 1999 Mar, 20(3), 493 - 9 Bacterial lipopolysaccharide induction of the prostaglandin G/H synthase 2 gene causes thromboxane-dependent pulmonary hypertension in rabbits; Delong P et al.; Two genes encode proteins with prostaglandin G/H synthase (PGHS) activity . PGHS-1 is primarily a constitutively expressed gene, whereas inflammatory agents such as bacterial lipopolysaccharide (LPS) endotoxin rapidly induce the PGHS-2 gene in leukocytes . Both PGHS-1 and PGHS-2 are rate-limiting enzymes for the production of prostaglandins and thromboxane following release of arachidonic acid by phospholipases . We previously reported that LPS perfusion into the circulation of isolated perfused rabbit lung (IPL) results in thromboxane-dependent pulmonary hypertension and lung edema when the LPS-primed lung is subsequently stimulated with platelet activating factor (PAF) (J . Clin . Invest . 1990;85:1135) . In this study, we showed that the mechanism by which LPS primes IPL for enhanced production of thromboxane and pulmonary hypertension in response to PAF depends on specific upregulation of the PGHS-2 gene in the rabbit lung . LPS perfusion of IPL induced PGHS-2 gene expression, which correlated with the conversion of free arachidonic acid to thromboxane-B2 (TXB2) and the onset of pulmonary hypertension . LPS-induced PGHS-2 expression, TXB2 release, and pulmonary hypertension were inhibited by actinomycin D (an inhibitor of transcription) and cycloheximide (an inhibitor of protein synthesis) . The constitutively expressed PGHS-1 remained unchanged with LPS perfusion, and did not convert free arachidonic acid to TXB2, suggesting that PGHS-1 does not contribute to the induction of pulmonary hypertension by LPS . These studies reveal a pathogenic role for induction of PGHS-2 in lung injury. FEMS Immunol Med Microbiol, 1999 Jan, 23(1), 67 - 73 A typical bacterial ornithine-containing lipid Nalpha-(D)-{3-(hexadecanoyloxy)hexadecanoyl}-ornithine is a strong stimulant for macrophages and a useful adjuvant; Kawai Y et al.; Nalpha-{3-(Hexadecanoyloxy)hexadecanoyl}-ornithine is a typical bacterial ornithine-containing lipid (OL) . The configuration of the 3-hydroxy fatty acids in the OL was proved to be D by using HPLC with chiral column . For this analysis, Nalpha-(D or L)-{3-(hexadecanoyloxy)hexadecanoyl}-L-ornithine were synthesized and used as standards . The typical bacterial OL, as well as the synthesized one, exhibited strong interleukin-1- and prostaglandin E2-inducing activities, and further, it induced the production of high IgG anti-tetanus toxoid antibodies in mice . The typical OL is expected to be utilized as a nontoxic, potent adjuvant. Vet J, 1999 Jan, 157(1), 85 - 9 A comparison of endoscopic and surgical collection procedures for the analysis of the bacterial flora in duodenal fluid from cats; Johnston KL et al.; In order to assess an endoscopic collection procedure, populations of bacteria in duodenal fluid from seven adult cats were compared in paired samples obtained by endoscopy and direct needle aspiration during laparotomy . Each sample of duodenal juice was subjected to quantitative and qualitative culture of bacteria under both aerobic and anaerobic conditions . There were no significant differences in total numbers or individual species of bacteria comparing the two collection procedures . These findings indicate that collection of duodenal juice by endoscopy using the procedure described provides a representative sample of small bowel fluid for the assessment of the bacterial flora . Therefore, there appears to be no need for more invasive or complicated sampling techniques when quantitative and qualitative culture of duodenal juice is indicated as part of an investigation of small bowel disease in cats. Fam Plann Perspect, 1999 Jan-Feb, 31(1), 4 - 9, 23 Correlates of sexually transmitted bacterial infections among U.S . women in 1995; Miller HG et al.; CONTEXT: Sexually transmitted diseases (STDs) of bacterial origin such as gonorrhea and chlamydial infection can lead to pelvic inflammatory disease (PID) and infertility . Identifying behaviors and characteristics associated with infection may assist in preventing these often asymptomatic diseases and their sequelae . METHODS: Data from 9,882 sexually active women who participated in the 1995 National Survey of Family Growth describe the characteristics of women who report a history of infection with a bacterial STD or of treatment for PID . Multivariate analysis is used to determine which demographic characteristics and sexual and health-related behaviors affect the likelihood of infection or the occurrence of complications . RESULTS: Overall, 6% of sexually active women reported a history of a bacterial STD, and 8% reported a history of PID . Women who first had sexual intercourse before age 15 were nearly four times as likely to report a bacterial STD, and more than twice as likely to report PID, as were women who first had sex after age 18 . Having more than five lifetime sexual partners also was associated with both having an STD and having PID . PID was more common among women reporting a history of a bacterial STD (23%) than among women who reported no such history (7%) . In multivariate analyses, age, race, age at first intercourse and lifetime number of sexual partners had a significant effect on the risk of a bacterial STD . Education, age, a history of IUD use, douching and a history of a bacterial STD had a significant impact on the risk of PID, but early onset of intercourse did not, and lifetime number of partners had only a marginal effect . CONCLUSIONS: The pattern of characteristics and behaviors that place women at risk of infection with bacterial STDs is not uniform among groups of women . Further, the level of self-reported PID would suggest higher rates of gonorrhea and chlamydial infection than reported. Clin Infect Dis, 1999 Jan, 28 Suppl 1, S57 - 65 Bacterial vaginosis: review of treatment options and potential clinical indications for therapy; Joesoef MR et al.; We reviewed data on the treatment of bacterial vaginosis published from 1993 through 1996 . For nonpregnant women, we recommend use of metronidazole (500 mg orally twice daily for 7 days), clindamycin vaginal cream (2%, once daily for 7 days), or metronidazole vaginal gel (0.75%, twice daily for 5 days) as the preferred treatment for bacterial vaginosis . For pregnant high-risk women (women with a prior preterm birth), the objective of the treatment is to prevent adverse outcomes of pregnancy, in addition to relief of symptoms . Thus, systemic therapy for possible subclinical upper tract infection as well as medication that has been studied in pregnant women are preferable . Therefore, we recommend metronidazole (250 mg orally three times a day for 7 days) . For pregnant low-risk women (women without a prior preterm birth) with symptomatic disease, the main objective of the treatment is to relieve symptoms . We recommend metronidazole (250 mg orally three times a day for 7 days) . Data do not support routine treatment of male sex partners. Pediatr Dermatol, 1999 Jan-Feb, 16(1), 19 - 22 Selective antibody deficiency to bacterial polysaccharide antigens in patients with Netherton syndrome; Stryk S et al.; Three patients with Netherton syndrome, recurrent sinopulmonary infections, and humoral immune deficiency are described . Although quantitative serum immunoglobulin levels were generally normal, two patients had selective antibody deficiency to bacterial polysaccharide antigens, one associated with IgA-IgG-2 deficiency . A third patient had an antibody deficiency to protein antigens . This is the first report, to our knowledge, that describes antibody deficiency in patients with Netherton syndrome . This finding demonstrates the importance of evaluating functional antibody responses to both protein and bacterial polysaccharide antigens and not relying on IgG subclass determination. Arthritis Rheum, 1999 Feb, 42(2), 210 - 20 Overexpression of human homologs of the bacterial DnaJ chaperone in the synovial tissue of patients with rheumatoid arthritis; Kurzik-Dumke U et al.; OBJECTIVE: To study the expression of the chaperone family of J proteins in the synovial tissue of patients with rheumatoid arthritis (RA) or osteoarthritis . METHODS: Rabbit antibodies specific for a synthetic peptide (pHSJ1: EAYEVLSDKHKREIYD), representing the most conserved part of all J domains thus far identified--among them the Drosophila tumor suppressor Tid56--were used in immunohistochemical analyses of frozen sections of synovial tissue and immunoblotting of protein extracts of adherent synovial cells . IgG specific for Tid56 was also used . RESULTS: Both antisera predominantly and intensely stained synovial lining cells from RA patients; other cells did not stain or stained only faintly . In immunoblots, anti-pHSJ1 specifically detected several bands with molecular weights of >74 kd (type I), 57-64 kd (type II), 41-48 kd (type III), and < or =36 kd (type IV) . The strongest band detected in RA adherent synovial cells was the type II band, whereas in a B cell line, a type I band was prominent . CONCLUSION: Several potentially new members of the J family are described . The type II band represents the human homolog of the Drosophila Tid56 protein and is strongly expressed in RA synovial tissue. No To Hattatsu, 1999 Jan, 31(1), 76 - 9 {Two cases of recurrent bacterial meningitis following traumatic cerebrospinal fluid rinorrhea}; Ikeda S et al.; We report here two cases of recurrent bacterial meningitis following traumatic cerebrospinal fluid rhinorrhea . Case-1: an 1-year-old girl had a penetrating injury to the nasal cavity with a chopstick . From 1 day after this accident, she had suffered from recurrent bacterial meningitis . She was diagnosed as having cerebrospinal fluid rhinorrhea, and underwent surgical repair of the bone defect . Case-2: a 5-year-old girl had suffered from bacterial meningitis 4 times after head trauma . A bone defect was demonstrated by 3-D CT and repaired surgically . We consider that 3-D CT is a useful tools to detect cerebrospinal fluid fistula. Infect Immun, 1999 Mar, 67(3), 1100 - 6 Transcutaneous immunization with bacterial ADP-ribosylating exotoxins as antigens and adjuvants; Glenn GM et al.; Transcutaneous immunization (TCI) is a new technique that uses the application of vaccine antigens in a solution on the skin to induce potent antibody responses without systemic or local toxicity . We have previously shown that cholera toxin (CT), a potent adjuvant for oral and nasal immunization, can induce both serum and mucosal immunoglobulin G (IgG) and IgA and protect against toxin-mediated mucosal disease when administered by the transcutaneous route . Additionally, CT acts as an adjuvant for coadministered antigens such as tetanus and diphtheria toxoids when applied to the skin . CT, a member of the bacterial ADP-ribosylating exotoxin (bARE) family, is most potent as an adjuvant when the A-B subunits are present and functional . We now show that TCI induces secondary antibody responses to coadministered antigens as well as to CT in response to boosting immunizations . IgG antibodies to coadministered antigens were also found in the stools and lung washes of immunized mice, suggesting that TCI may target mucosal pathogens . Mice immunized by the transcutaneous route with tetanus fragment C and CT developed anti-tetanus toxoid antibodies and were protected against systemic tetanus toxin challenge . We also show that bAREs, similarly organized as A-B subunits, as well as the B subunit of CT alone, induced antibody responses to themselves when given via TCI . Thus, TCI appears to induce potent, protective immune responses to both systemic and mucosal challenge and offers significant potential practical advantages for vaccine delivery. Lancet, 1999 Jan 9, 353(9147), 139 - 42 Bacterial infection in the pathogenesis of variceal bleeding; Goulis J et al.; Variceal bleeding is a life-threatening complication of cirrhosis . Potential risk factors include clinical, endoscopic, and haemodynamic factors, but why bleeding occurs unpredictably in individual patients is not known . We postulate that bacterial infections in patients with variceal haemorrhage may be the critical factor that triggers bleeding . In patients with large varices and a high wall tension, the release of endotoxin into the systemic circulation during episodes of bacterial infection results in a further increase in portal pressure through the induction of endothelin and possibly vasoconstrictive cyclo-oxygenase products . The subsequent contraction of hepatic stellate cells causes a rise in intrahepatic vascular resistance . Furthermore, endotoxin-induced nitric oxide and prostacyclin, and prostacyclin induced by endothelin could inhibit platelet aggregation, which may result in a further deterioration of primary haemostasis at the level of varix . We propose that the combination of these two effects leads to the onset of variceal haemorrhage. EMBO J, 1999 Feb 15, 18(4), 959 - 67 Anopheles gambiae Ag-STAT, a new insect member of the STAT family, is activated in response to bacterial infection; Barillas-Mury C et al.; A new insect member of the STAT family of transcription factors (Ag-STAT) has been cloned from the human malaria vector Anopheles gambiae . The domain involved in DNA interaction and the SH2 domain are well conserved . Ag-STAT is most similar to Drosophila D-STAT and to vertebrate STATs 5 and 6, constituting a proposed ancient class A of the STAT family . The mRNA is expressed at all developmental stages, and the protein is present in hemocytes, pericardial cells, midgut, skeletal muscle and fat body cells . There is no evidence of transcriptional activation following bacterial challenge . However, bacterial challenge results in nuclear translocation of Ag-STAT protein in fat body cells and induction of DNA-binding activity that recognizes a STAT target site . In vitro treatment with pervanadate (vanadate and H2O2) translocates Ag-STAT to the nucleus in midgut epithelial cells . This is the first evidence of direct participation of the STAT pathway in immune responses in insects. J Urol, 1999 Mar, 161(3), 964 - 9 Effects of bacterial endotoxin on the contraction and relaxation responses of the rabbit cavernous smooth muscles; Kim SC et al.; PURPOSE: We evaluated effects of bacterial endotoxin during septicemia on contraction and relaxation responses of cavernous smooth muscles in rabbits . MATERIALS AND METHODS: We performed isometric tension studies with norepinephrine (NE), endothelium-dependent and endothelium-independent vasodilators, and nonadrenergic noncholinergic (NANC)-selective electrical field stimulation on the muscle strips of control and endotoxin (lipopolysaccharide; LPS)-treated rabbits . To determine reversibility of the LPS effects on the cavernous smooth muscle, the contraction and relaxation studies were repeated after resting the strips for 1 day at 4C . We also investigated the effect of the nonspecific nitric oxide synthase (NOS) inhibitor (NW-nitro-L-arginine methyl ester; L-NAME) and the selective immunologic NOS inhibitor (aminoguanidine) on reactivity of the strips to NE and acetylcholine . RESULTS: Contractile response to NE was significantly (p <0.01) reduced in the cavernous smooth muscles from the systemically and locally LPS-treated rabbits, compared with control group . Both aminoguanidine and L-NAME markedly improved the diminished contraction of the strips . Relaxation response to endothelium-dependent agonists (acetylcholine and bradykinin) was significantly (p <0.05) decreased in the LPS-treated groups, compared with the control group but not to endothelium-independent vasodilators (papaverine and verapamil) and NANC-selective electrical field stimulation . L-NAME completely inhibited the relaxation response to acetylcholine in the control and LPS-treated groups but aminoguanidine did not . The impaired contraction and relaxation of the strips was completely restored after resting for 1 day . CONCLUSIONS: Bacterial endotoxin may cause non-endothelial overproduction of NO and inhibition of endothelium-derived NO production, which may contribute to impairment of contraction and relaxation of rabbit cavernous smooth muscles. Toxicol Lett, 1998 Dec 28, 102-103, 65 - 9 A transient brain ischemia- and bacterial endotoxin-induced glial iNOS expression and NO-induced neuronal apoptosis; Nomura Y; Astroglia cells seem to be closely involved in neuronal survival/death via neurotrophins, cytokines and so on . We found that a transient four-vessel occlusion/reperfusion induced glial iNOS expression and neuronal apoptosis in a CA1 region of the rat hippocampus . Bacterial endotoxin (LPS)/INFgamma induced iNOS expression in cultured C6 rat glioma cells . LPS caused intranuclear translocation of NF-kappaB, and IFNgamma induced phosphorylation of Jak2 and Stat1, followed by the translocation of Stat1 into the nucleus . A NO donor (SNP) caused chromosomal condensation and fragmentation of nuclei and internucleosomal DNA fragmentation in NG108-15 cells, suggesting NO-induced neuronal apoptosis . Koningic acid (KO), a chemical modifier and enzyme inhibitor of glyceraldehyde-3 phosphate dehydrogenase (GAPDH), induced the apoptosis too . In addition, a NO donor (NOC18)-induced apoptosis was inhibited by Z-Asp-CH2-DCB, a caspase inhibitor, in SH-SY5Y cells . NOC18 increased caspase 3-like proteolytic activity to a substrate (Ac-DEVD-MCA), indicating the involvement of caspase, at least caspase 3, in NO-induced neuronal apoptosis. Am J Trop Med Hyg, 1999 Jan, 60(1), 35 - 40 Bacterial expression of a neutralizing mouse monoclonal antibody Fab fragment to a 150-kilodalton surface antigen of Entamoeba histolytica; Tachibana H et al.; A mouse monoclonal antibody (MAb) (EH3015, IgG1 with a K light chain) prepared by hybridoma technology recognizes a 150-kD surface antigen of Entamoeba histolytica and inhibits adherence and cytotoxicity of the ameba to mammalian cells . The genes encoding the light chain and the Fd region of the heavy chain of the MAb were cloned and expressed in Escherichia coli . The plasmid used was designed for the expression of Fab with a hexa-histidine tag in the periplasmic space . Recombinant Fab fragments were purified and analyzed by an indirect immunofluorescence antibody test and Western immunoblot . The specificity of the recombinant Fab fragment was comparable with the parent whole IgG . In addition, the Fab fragments significantly inhibited the adherence of E . histolytica to erythrocytes . These results suggest that the production of a neutralizing MAb in Escherichia coli is practical and efficient with this expression system. Eur J Neurosci, 1999 Jan, 11(1), 178 - 86 Impaired glucocorticoid receptor function evolves in aberrant physiological responses to bacterial endotoxin; Linthorst AC et al.; The consequences of glucocorticoid receptor (GR) dysfunction for neuroimmunoendocrine responses to an inflammatory challenge were studied in transgenic mice expressing antisense RNA directed against the GR {GR-impaired (GR-i) mice} . Mice were implanted intraperitoneally with a biotelemetry transmitter to monitor body temperature and locomotion . GR-i mice showed decreased locomotion and body temperature during the dark phase of the diurnal cycle . Intraperitoneal administration of saline caused a rapid increase in body temperature in control mice, which was terminated within 90 min . In GR-i mice, however, body temperature remained elevated for about 6 h . Intraperitoneal injection of endotoxin (10 micrograms/mouse) produced a biphasic fever in control mice . However, in endotoxin-injected GR-i mice, body temperature was not significantly different from their saline-injected controls during the first 6 h . Body temperature then increased and remained elevated during the night period . Both strains showed hypolocomotion after endotoxin . In a second experiment, mice were injected intraperitoneally with saline or endotoxin and killed after 1, 3, 6 or 24 h . In GR-i mice, endotoxin caused an augmented rise in plasma ACTH, but not in corticosterone levels . The endotoxin-induced increase in serum levels of interleukin-1 beta and interleukin-6 was not different between the strains . However, whereas in control mice tumour necrosis factor-alpha levels were below detection at the time points studied, substantial levels of this cytokine were found in the serum of GR-i mice 1 h after endotoxin administration . It may be concluded that life-long impairment of GR evolves in aberrant physiological and humoral responses to an acute inflammatory challenge . These findings expand our understanding about the neuroendocrine and physiological disturbances associated with stress-related disorders. J Acquir Immune Defic Syndr Hum Retrovirol, 1999 Feb 1, 20(2), 201 - 6 Effect of trimethoprim-sulfamethoxazole as Pneumocystis carinii pneumonia prophylaxis on bacterial illness, Pneumocystis carinii pneumonia, and death in persons with AIDS; Buskin SE et al.; To measure the effect of trimethoprim-sulfamethoxazole (TMP-SMX) in preventing bacterial illness, Pneumocystis carinii pneumonia (PCP), and death in people with AIDS, we conducted a retrospective medical record review of 1078 persons who were observed for 3 years on average who attended nine outpatient facilities in Seattle, Washington between January 1990 and April 1996 . We calculated relative risk estimates to measure the protective effect of TMP-SMX on the development of major bacterial illnesses, PCP, and death . Use of TMP-SMX decreased the risk of PCP (relative risk {RR} = 0.23; 95% confidence interval {CI}, 0.14-0.36) and deaths not attributable to PCP (RR = 0.59; 95% CI, 0.47-0.73) . Prevention of major bacterial illnesses of known etiology was of borderline significance (RR = 0.77; 95% CI, 0.57-1.05) and became statistically significant with the addition of patients with infections of unknown etiology (RR = 0.77; 95% CI 0.61-0.97) . Use of TMP-SMX PCP prophylaxis significantly reduced the risks of death and of PCP and was associated with a trend toward reduced risk of major bacterial infections. J Immunol, 1999 Feb 15, 162(4), 1884 - 8 Cutting edge: chronic intestinal inflammation in STAT-4 transgenic mice: characterization of disease and adoptive transfer by TNF- plus IFN-gamma-producing CD4+ T cells that respond to bacterial antigens; Wirtz S et al.; We generated transgenic mice for STAT-4, a regulatory protein specifically associated with IL-12 signaling, under the control of a CMV promoter . These mice expressed strikingly increased nuclear STAT-4 levels in lamina propria CD4+ T lymphocytes upon systemic administration of dinitrophenyl-keyhole limpet hemocyanin and developed chronic transmural colitis characterized by infiltrates of mainly CD4+ T lymphocytes . The latter cells produced predominantly TNF and IFN-gamma but not IL-4 upon activation with alphaCD3/CD28 or autologous bacterial Ags, consistent with a Th1-type cell response . Furthermore, chronic colitis in STAT-4 transgenic mice could be adoptively transferred to SCID mice by colonic and splenic CD4+ T cells that were activated with Ags from autologous bacterial flora . These data establish a critical molecular signaling pathway involving STAT-4 for the pathogenesis of chronic intestinal inflammation, and targeting of this pathway may be relevant for the treatment of colitis in humans. J Electron Microsc (Tokyo), 1998, 47(6), 543 - 52 Characterization of the damage to membranes caused by bacterial cytolysins; Sekiya K et al.; The damage to cell membranes caused by bacterial cytolysins has been studied for many years . In this review, we attempt to summarize the historical contribution of electron microscopy to our understanding of the modes of action of pore-forming and channel-forming toxins . We describe the ways in which these toxins form holes in membranes by binding to and forming oligomers on biological membranes . We also introduce the new technique of electron spectroscopic imaging (ESI) with an imaging plate (IP), which has been used to analyse the mechanisms of membrane damage by cytolysins. Hepatogastroenterology, 1998 Nov-Dec, 45(24), 2165 - 70 Heavy bacterial loads of H . pylori may precipitate duodenal ulcer bleeding but not bleeding severity; Bor-Shyang S et al.; BACKGROUND/AIMS: To determine whether severity of Helicobacter pylori (H . pylori) infection is aggravated during acute duodenal ulcer bleeding and related to bleeding severity . METHODOLOGY: One hundred and thirty-eight patients with H . pylori-infected bleeding duodenal ulcer and 112 non-bleeding cases were included in the study . A comparison was made of the anti-H . pylori IgG titer, endoscopic finding, density of H . pylori (range: 1-5) in the antrum, and severity of antral gastritis (score: 0-3) between bleeding and non-bleeding cases . The role of H . pylori in bleeding cases was further analyzed to survey its relationship to the severity of bleeding judged by clinical parameters . The H . pylori status of patients with rebleeding within the first week was compared to that of the non-rebleeding cases as well . RESULTS: The anti-H . pylori IgG titer and H . pylori density of the non-bleeding group were lower than those of the bleeding group (0.466+/-0.288 vs . 0.912+/-0.559, p<0.001; 2.13+/-1.02 vs . 3.34+/-1.32, p<0.001) . The percentages of bleeding ulcers in the study cases increased in a trend as the density of H . pylori increased (density: 1-5; 32.7%, 33.8%, 57.4%, 81.3%, 91.4%, p<0.001) . Although the severity of gastritis and density of H . pylori disclosed an upward trend as bleeding severity increased, only ulcer size was significantly associated with bleeding severity (p<0.05) . The 10 cases with recurrent bleeding had higher bacterial density and serological titer than the 128 non-rebleeding cases (p<0.005) . CONCLUSIONS: Heavy bacterial loads of H . pylori infection may precipitate bleeding episodes of duodenal ulcer . However, in bleeding duodenal ulcer, the status of H . pylori infection is not strongly associated with initial bleeding severity before therapeutic endoscopy . With the aim of enhancing hemostasis and preventing rebleeding, further studies could focus on diminishing the bacterial load of H . pylori during bleeding episodes. Ter Arkh, 1998, 70(11), 72 - 4 {Clinico-biochemical effectiveness of emoxpine in patients with bacterial bronchial asthma}; Lapik SV et al.; AIM: To determine effectiveness of a synthetic antioxidant drug emoxipine in combined treatment of bacterial bronchial asthma (BBA) . MATERIALS AND METHODS: A total of 59 BBA patients were treated who had the disease for 1-14 years . The previous treatment consisted of bronchodilating, mucolytic and expectorant drugs . 19 of them received i.m . adjuvant emoxipine for 10 days in daily dose 0.3 mg/kg as a 1% aqueous solution . Metabolic activity of alveolar macrophages (AM) was measured . RESULTS: Emoxipine-treated patients had reduced content of primary lipid peroxidation products and schiff bases in AM, catalase level in them returned to normal, blood levels of alpha-tocopherol went up . CONCLUSION: Emoxipine is beneficial for AM antioxidant defence system in BBA patients. Surg Today, 1999, 29(1), 47 - 50 Hypertonic saline prevents early bacterial translocation in hemorrhagic shock; Topaloglu U et al.; The most appropriate solution for volume replacement in hemorrhagic shock is controversial; however, hypertonic saline (HTS) solutions have recently gained widespread acceptance . In this study, various solutions were used to resuscitate rats in hemorrhagic shock, and their impact on the extent of bacterial translocation was investigated . Rats were bled to a mean arterial blood pressure of about 35 mmHg which was maintained for 30 min . They were then randomized into six groups . Blood pressure was found to be regulated by blood + lactated Ringer's solution (LR) and HTS + LR, but no significant improvement was observed in the control and LR groups . Groups II (7.5% HTS + 60 ml/kg LR) and IV (60 ml/kg LR + autologous blood) had a significantly better result than groups I (7.5% HTS), III (60 ml/kg LR), and IV (P < 0.05), among which no statistically different results were seen (P > 0.05) . While no organisms were isolated from the mesenteric lymph nodes in the sham group, the rates of positive culture were 12.5%, 12.5%, 50%, 62.5%, and 62.5% in groups I, II, III, and the control group, respectively . Escherichia coli was the most commonly isolated organism . HTS + LR was demonstrated to be effective for decreasing the rate of early bacterial translocation to mesenteric lymph nodes and also for restoring the mean arterial pressure. Eur J Immunol, 1999 Jan, 29(1), 109 - 18 Neonatal colonization of rats induces immunological tolerance to bacterial antigens; Karlsson MR et al.; We wanted to investigate the immunological events occurring in rats intestinally colonized from birth (neonatally) or at adult age with an ovalbumin (OVA)-producing Escherichia coli O6K13 strain, carrying type 1 pili . The neonatally colonized animals responded with lower delayed type hypersensitivity (DTH) against OVA and lower levels of IgG antibodies against OVA, O6 lipopolysaccharide (LPS) and type 1 pili compared to age-matched controls . The IgG antibody response against the bystander antigen, human serum albumin (HSA), was lower in the neonatally colonized animals than in the controls co-immunized with HSA and E . coli, indicating a release of suppressive factors induced by the bacterial antigens . The adult colonized animals showed an increased DTH and antibody response against OVA after immunization . They also had high pre-immunization levels of IgG anti-O6 LPS antibodies compared to controls . However, the relative increase in IgG anti-O6 LPS antibody levels after the immunization with dead E . coli was much lower in the adult colonized animals . The present results suggest that neonatal animals develop tolerance against antigen on bacterial colonizers of the intestine . In addition, this tolerance contains components of suppression. Electrophoresis, 1998 Dec, 19(18), 3062 - 8 Preparative separation of plasmid and bacterial artificial chromosome DNA by density gradient electrophoresis in the presence of linear polymers; Cole KD; A density gradient apparatus was used to examine the separation of different physical forms and sizes of DNA . A gradient of sucrose was used to stabilize thermal convection during electrophoresis in the column (2.2 cm in diameter) . Linear polymers were added to the density gradient and screened for their ability to separate the supercoiled, nicked circular, and linear forms of the plasmid pBR 322 . The influence of different concentrations and molecular weights of the polymers was examined on the separation . Polyethylene oxide with a molecular weight of 5,000,000 and a concentration of 0.2% w/v achieved the best separation results for the different physical forms of the plasmid . The order of separation of the different physical forms of the plasmid were linear (fastest), supercoiled, and nicked circular (slowest) . These conditions were also used to separate a preparation of bacterial artificial chromosome (BAC) DNA . A rapidly moving form, presumably the supercoiled form, was resolved from a large amount of E . coli genomic DNA and from sheared forms of the BAC DNA. Acta Neurochir (Wien), 1998, 140(12), 1263 - 70 Current treatment strategies and factors influencing outcome in patients with bacterial brain abscess; Takeshita M et al.; We clearly determined the key to managing patients with brain abscess by retrospectively evaluating the factors affecting poor outcome in these patients . This study included 113 patients with brain abscess diagnosed in the CT era . Basic characteristics and therapeutic parameters were estimated as independent predictors of poor outcome by using univariate and multivariate logistic regression analysis . Patients with poor outcomes more frequently had deeply-located abscesses (p < 0.02), IVROBA (intraventricular rupture of brain abscess (p < 0.001) and were in a severely deteriorated neurological state (p < 0.001) than those with good outcomes . Multiple logistic regression analysis predicted that IVROBA (ORs, 24.5; 95% CI, 3.04 to 197.9) and severely deteriorated cases (ORs, 13.7; 95% CI, 2.34 to 80.8) resulting from IVROBA increased the relative risk of poor outcome . Patients with IVROBA more frequently had also deeply-located abscesses (p < 0.005), positively immunocompromised states (p < 0.05) and were in a severely deteriorated condition (p < 0.003) than those without IVROBA . Patients with metastatic abscess had also IVROBA (p < 0.006) . Multiple logistic regression analysis anticipated that deeply-located abscess (ORs, 3.90; 95% CI, 1.38 to 11.04), and metastatic abscess (ORs, 12.26; 95% CI, 1.35 to 111.2) increased the relative risk of IVROBA . Patients in an obtunded state and with marked neurological deficit had IVROBA more often than patients in an alert state and/or mild neurological deficit (ORs, 3.23; 95% CI, 1.17 to 8.86, p < 0.03) before treatment . Our findings suggest that IVROBA strongly influences poor outcome in patients with brain abscess . The key to decreasing poor outcomes may be the prevention and management of IVROBA, by evaluating intracranial pressure pathophysiology . IVROBA should be aggressively treated by aspiration methods for the abscess coupled with appropriate intravenous and intrathecial administration of antibiotics. Ann Otol Rhinol Laryngol, 1999 Jan, 108(1), 87 - 90 Carotid artery occlusion due to bacterial paranasal sinusitis; Ozuer MZ et al.; Complications of paranasal sinusitis still continue to be a serious health problem . We present an orbita-related complication of sinusitis in a patient with diabetic ketoacidosis . It was not a rhinocerebral mucormycosis, but a bacterial sinusitis-induced development of left cavernous sinus thrombophlebitis and carotid artery occlusion . We discuss the diagnosis, surgical options, and clinical outcome. Lipids, 1998 Dec, 33(12), 1213 - 6 Phytanic acid alpha-hydroxylation by bacterial cytochrome P450; Matsunaga I et al.; Fatty acid alpha-hydroxylase, a cytochrome P450 enzyme, from Sphingomonas paucimobilis, utilizes various straight-chain fatty acids as substrates . We investigated whether a recombinant fatty acid alpha-hydroxylase is able to metabolize phytanic acid, a methyl-branched fatty acid . When phytanic acid was incubated with the recombinant enzyme in the presence of H2O2, a reaction product was detected by gas chromatography, whereas a reaction product was not detected in the absence of H2O2 . When a heat-inactivated enzyme was used, a reaction product was not detected with any concentration of H2O2 . Analysis of the methylated product by gas chromatography-mass spectrometry revealed a fragmentation pattern of 2-hydroxyphytanic acid methyl ester . By single-ion monitoring, the mass ion and the characteristic fragmentation ions of 2-hydroxyphytanic acid methyl ester were detected at the retention time corresponding to the time of the product observed on the gas chromatogram . The Km value for phytanic acid was approximately 50 microM, which was similar to that for myristic acid, although the calculated Vmax for phytanic acid was about 15-fold lower than that for myristic acid . These results indicate that a bacterial cytochrome P450 is able to oxidize phytanic acid to form 2-hydroxyphytanic acid. Annu Rev Genet, 1998, 32, 339 - 77 The diverse and dynamic structure of bacterial genomes; Casjens S; Bacterial genome sizes, which range from 500 to 10,000 kbp, are within the current scope of operation of large-scale nucleotide sequence determination facilities . To date, 8 complete bacterial genomes have been sequenced, and at least 40 more will be completed in the near future . Such projects give wonderfully detailed information concerning the structure of the organism's genes and the overall organization of the sequenced genomes . It will be very important to put this incredible wealth of detail into a larger biological picture: How does this information apply to the genomes of related genera, related species, or even other individuals from the same species? Recent advances in pulsed-field gel electrophoretic technology have facilitated the construction of complete and accurate physical maps of bacterial chromosomes, and the many maps constructed in the past decade have revealed unexpected and substantial differences in genome size and organization even among closely related bacteria . This review focuses on this recently appreciated plasticity in structure of bacterial genomes, and diversity in genome size, replicon geometry, and chromosome number are discussed at inter- and intraspecies levels. Infect Control Hosp Epidemiol, 1999 Jan, 20(1), 58 - 60 Bacterial filters in anesthesia: results of 9 years of surveillance; van Hassel S et al.; In 9 years of surveillance of postoperative lower respiratory infections, the infection rate in patients following regional anesthesia was 0.2% and 0.1% in patients following general anesthesia . No bacterial filters in the breathing circuit were used . Infected patients had risk factors such as type of surgery, American Society of Anesthesiologists class > or =2, old age, chronic obstructive pulmonary disease, or smoking habits . Infections were not clustered . This suggests that, in our setting, patient factors are most important in the development of postoperative lower respiratory infections and that the role of bacterial filters as a preventive measure is negligible. Appl Environ Microbiol, 1999 Feb, 65(2), 732 - 6 Estimating bacterial growth parameters by means of detection times; Baranyi J et al.; We developed a new numerical method to estimate bacterial growth parameters by means of detection times generated by different initial counts . The observed detection times are subjected to a transformation involving the (unknown) maximum specific growth rate and the (known) ratios between the different inoculum sizes and the constant detectable level of counts . We present an analysis of variance (ANOVA) protocol based on a theoretical result according to which, if the specific rate used for the transformation is correct, the transformed values are scattered around the same mean irrespective of the original inoculum sizes . That mean, termed the physiological state of the inoculum, alpha, and the maximum specific growth rate, mu, can be estimated by minimizing the variance ratio of the ANOVA procedure . The lag time of the population can be calculated as lambda = -ln alpha/mu; i.e . the lag is inversely proportional to the maximum specific growth rate and depends on the initial physiological state of the population . The more accurately the cell number at the detection level is known, the better the estimate for the variance of the lag times of the individual cells. J Endocrinol, 1999 Feb, 160(2), 291 - 6 Effect of bacterial endotoxin on the in vitro release of Type II phospholipase-A2 and prostaglandin E2 from human placenta; Farrugia W et al.; The aim of this study was to establish the effect of bacterial endotoxin lipopolysaccharide (LPS) on the release of Type II phospholipase-A2 (PLA2) and prostaglandin E2 (PGE2) from late-pregnant human placental tissue incubated in vitro . Under basal conditions, immunoreactive Type II PLA2 and PGE2 were released from tissue explants in a time-dependent manner (up to 24 h, ANOVA, P<0 . 0001, n=6) . The release of these mediators was not associated with a loss of cell membrane integrity, as indicated by concentrations of the intracellular enzyme, lactate dehydrogenase (LDH), in the incubation medium . Incubation of explants in the presence of LPS (0 . 001-100 microg LPS/ml) significantly decreased PLA2 tissue content (P<0.02, n=6) and increased the accumulation of PLA2 and PGE2 in the incubation medium (P<0.0001, n=6) . The data obtained in this study indicated that Type II PLA2 and PGE2 are released from term placenta under basal conditions and that LPS stimulated their release . The associated decrease in PLA2 tissue content is consistent with the hypothesis that LPS induces the release of stored PLA2 . This study identifies one pathway by which products of bacterial infection may induce the release of a pro-inflammatory, extracellularly active PLA2 from intrauterine tissues that may promote the formation of phospholipid metabolites involved in the process of labour and delivery (e.g . the prostaglandins). Nature, 1999 Jan 14, 397(6715), 168 - 71 Robustness in bacterial chemotaxis; Alon U et al.; Networks of interacting proteins orchestrate the responses of living cells to a variety of external stimuli, but how sensitive is the functioning of these protein networks to variations in their biochemical parameters? One possibility is that to achieve appropriate function, the reaction rate constants and enzyme concentrations need to be adjusted in a precise manner, and any deviation from these 'fine-tuned' values ruins the network's performance . An alternative possibility is that key properties of biochemical networks are robust; that is, they are insensitive to the precise values of the biochemical parameters . Here we address this issue in experiments using chemotaxis of Escherichia coli, one of the best-characterized sensory systems . We focus on how response and adaptation to attractant signals vary with systematic changes in the intracellular concentration of the components of the chemotaxis network . We find that some properties, such as steady-state behaviour and adaptation time, show strong variations in response to varying protein concentrations . In contrast, the precision of adaptation is robust and does not vary with the protein concentrations . This is consistent with a recently proposed molecular mechanism for exact adaptation, where robustness is a direct consequence of the network's architecture. Acta Chir Belg, 1998 Dec, 98(6), 245 - 9 The effect of intestinal transit time on bacterial translocation; Erbil Y et al.; Increase in intraluminal bacterial count, disruption of the mucosal integrity, changes in intestinal immunity and transit time are the factors involved in bacterial translocation . The relationship between intestinal transit time, intra luminal bacterial count and translocation rate were investigated in 40 Wistar-albino rats . The study was conducted in 4 groups with 10 animals in each . Group I (controls): saline + laboratory chow, Group II: saline + oral total parenteral nutrition (TPN) solution, Group III: morphine sulfate (MS) + oral TPN solution, Group IV: neostigmine bromide (NB) + oral TPN solution . Intestinal transit time was measured by using Indium111-labeled diethylene triamine pentaacetic acid (DTPA) . It was prolonged in the MS-treated group and shortened in the NB-treated group (p < 0.01) . The frequency of bacterial translocation was 60% in the oral TPN solution group, 100% in the MS-treated group, 20% in the NB-treated group and 10% in controls . Bacterial counts in duodenum, jejunum, ileum and caecum were significantly increased (p < 0.001) in the MS-treated group and decreased (p < 0.05) in the NB-treated group in comparison with the control group . In conclusion, the prolongation of intestinal transit time increased the intraluminal bacterial count and augmented bacterial translocation . The decrease in intestinal transit time had a converse effect. Gastroenterology, 1999 Feb, 116(2), 431 - 7 Effect of bacterial or porcine lipase with low- or high-fat diets on nutrient absorption in pancreatic-insufficient dogs; Suzuki A et al.; BACKGROUND & AIMS: Treatment of human exocrine pancreatic insufficiency is suboptimal . This study assessed the effects of bacterial lipase, porcine lipase, and diets on carbohydrate, fat, and protein absorption in pancreatic-insufficient dogs . METHODS: Dogs were given bacterial or porcine lipase and 3 diets: a 48% carbohydrate, 27% fat, and 25% protein standard diet; a high-carbohydrate, low-fat, and low-protein diet; or a low-carbohydrate, high-fat, and high-protein diet (66%/18%/16% and 21%/43%/36% calories) . RESULTS: With the standard diet, coefficient of fat absorption increased dose-dependently with both lipases (P < 0.05), but more fat was absorbed with porcine lipase (P < 0.05); 600, 000 IU of bacterial lipase (240 mg) and 300,000 IU of porcine lipase (18 g) nearly abolished steatorrhea . With 300,000 IU of bacterial lipase or 135,000 IU of porcine lipase, fat absorption was greater with the high-fat and -protein diet (P < 0.05 vs . low-fat and -protein diet) . There were no interactions among carbohydrate, fat, and protein absorption . CONCLUSIONS: Correcting steatorrhea requires 75 times more porcine than bacterial lipase (18 vs . 240 mg) . High-fat and high-protein diets optimize fat absorption with both enzymes . High-fat diets with bacterial or porcine lipase should be evaluated in humans with pancreatic steatorrhea. J Bacteriol, 1999 Feb, 181(3), 941 - 8 Phenotypic analysis of random hns mutations differentiate DNA-binding activity from properties of fimA promoter inversion modulation and bacterial motility; Donato GM et al.; H-NS is a major Escherichia coli nucleoid-associated protein involved in bacterial DNA condensation and global modulation of gene expression . This protein exists in cells as at least two different isoforms separable by isoelectric focusing . Among other phenotypes, mutations in hns result in constitutive expression of the proU and fimB genes, increased fimA promoter inversion rates, and repression of the flhCD master operon required for flagellum biosynthesis . To understand the relationship between H-NS structure and function, we transformed a cloned hns gene into a mutator strain and collected a series of mutant alleles that failed to repress proU expression . Each of these isolated hns mutant alleles also failed to repress fimB expression, suggesting that H-NS-specific repression of proU and fimB occurs by similar mechanisms . Conversely, alleles encoding single amino acid substitutions in the C-terminal DNA-binding domain of H-NS resulted in significantly reduced affinity for DNA yet conferred a wild-type fimA promoter inversion frequency, indicating that the mechanism of H-NS activity in modulating promoter inversion is independent of DNA binding . Furthermore, two specific H-NS amino acid substitutions resulted in hypermotile bacteria, while C-terminal H-NS truncations exhibited reduced motility . We also analyzed H-NS isoform composition expressed by various hns mutations and found that the N-terminal 67 amino acids were sufficient to support posttranslational modification and that substitutions at positions 18 and 26 resulted in the expression of a single H-NS isoform . These results are discussed in terms of H-NS domain organization and implications for biological activity. Biochem Biophys Res Commun, 1999 Jan 8, 254(1), 65 - 9 Bacterial expression, purification, and characterization of a novel mouse sulfotransferase that catalyzes the sulfation of eicosanoids; Liu MC et al.; Analysis of the nucleotide sequence of a recently cloned mouse sulfotransferase cDNA (clone 679153) revealed the presence in its 3'-untranslated sequence of an AT-rich region which contains four ATTTA motifs and an TTATTTAT-like sequence, commonly found among those encoding inflammation-related proteins . The recombinant enzyme expressed in Escherichia coli and purified to near electrophoretic homogeneity displayed strong sulfotransferase activities toward various prostaglandins, thromboxane B2, and leukotriene E4 . These results mark the first discovery of the sulfation of eicosanoids catalyzed by a distinct sulfotransferase . Mutat Res, 1998 Nov 9, 422(1), 85 - 95 Bacterial gene products in response to near-ultraviolet radiation; Eisenstark A; Our research has focused on bacterial gene products that protect cells from damage by near-ultraviolet radiation (near-UV) including gene products involved in the subsequent recovery process . Protective gene products include such anti-oxidants as catalases, superoxide dismutases and glutathione reductase . Near-UV damage recovery products include exonuclease III and DNA-glycosylases . Perhaps more critical than the products of structural genes are certain regulatory gene products that are triggered upon excess near-UV oxidation and lead to synthesis of entire batteries of anti-oxidant enzymes, DNA repair enzymes, and DNA-integrity proteins . Our recent experiments have focused on RpoS and its interaction with OxyR, two proteins that regulate the synthesis of molecules that protect cells from near-UV and other oxidative stresses. Obstet Gynecol, 1999 Jan, 93(1), 117 - 23 Association between bacterial vaginosis and fetal fibronectin at 24-29 weeks' gestation; Pastore LM et al.; OBJECTIVE: To investigate the relationship between fetal fibronectin and bacterial vaginosis, which are associated with an increased risk for preterm delivery . METHODS: Researchers for the Pregnancy, Infection and Nutrition Study, a cohort study of pregnant women at three central North Carolina sites, collected genital tract specimens from all enrolled women between 24 and 29 weeks' gestation . Among women with last menstrual periods between March 10, 1995, and August 15, 1996, 868 pregnancies were eligible for this analysis . Fetal fibronectin was assessed by a dipstick immunoassay kit . Bacterial vaginosis was evaluated by Nugent-scored, Gram-stained vaginal smears (scores of 7-10 considered positive) . RESULTS: Overall, 6.3% of women had positive fetal fibronectin test results, and 18.8% had bacterial vaginosis . The unadjusted relative risk (RR) of fetal fibronectin-positivity comparing women with bacterial vaginosis to those without bacterial vaginosis was 1.6 (95% confidence interval {CI} 1.1, 2.5) . Using multiple logistic regression to adjust for race, maternal age, parity, and location of care, women who had bacterial vaginosis and smoked at the time of recruitment were at substantially increased risk of fetal fibronectin-positivity (RR 7.8, 95% CI 2.2, 27.8) compared with smokers without bacterial vaginosis . Among nonsmokers, bacterial vaginosis was not associated with fetal fibronectin-positivity (RR 1.0, 95% CI 0.4, 2.4) . These results were essentially unchanged after adding the requirement of vaginal pH exceeding 4.5 to the bacterial vaginosis definition . CONCLUSION: Fetal fibronectin was associated positively with bacterial vaginosis, but only among women who smoked . These results might provide clues as to the biologic relationship between smoking, infection, and preterm delivery. J Laparoendosc Adv Surg Tech A, 1998 Dec, 8(6), 401 - 7 Does pneumoperitoneum cause bacterial translocation? Tug T, Ozbas S, Tekeli A, Gundogdu H, Doseyen Z, Kuzu I. Although extensive research has been carried out on the respiratory and renal effects of intra-abdominal pressure increase, there is limited research with regard to its effects on bacterial translocation . The objective of this study was to discuss whether the high intra-abdominal pressure due to carbon dioxide (CO2) insufflation during laparoscopy leads to bacterial translocation . Eighteen male dogs, 7 of which constituted the control group, were used in the study . Two study groups, in which the intra-abdominal pressure was raised to 15 mm Hg and kept at that level for 30 and 120 minutes, respectively, were set . Blood gases and blood pressure values were observed throughout the experiments . Samples of peritoneal smear, portal vein blood, mesenteric lymph node, liver, spleen, and cecum were examined to detect bacterial translocation . Histopathological examinations of all samples were also carried out . No translocation was detected in the samples of peritoneal smear, portal blood, mesenteric lymph node, liver, or spleen, but in the samples of cecum, bacterial colonization for the second group (p<0.05) and for the third group (p<0.05) was significantly higher compared with the control group . There was a considerable difference between the second and third groups (p<0.05) . The changes in the mesenteric lymph nodes were interpreted to be a result of bacterial drainage . Histopathological examination disclosed active changes in the mesenteric lymph nodes in all groups, but there was considerable sinus histiocytosis only in the third group . We conclude that the intraabdominal pressure of 15 mm Hg created by carbon dioxide insufflation does not lead to bacterial translocation but causes intraluminal bacterial colonization in the cecum after 30 minutes and after 2 hours. Bull Acad Natl Med, 1998, 182(7), 1469 - 75; discussion 1475-7 {Procalcitonin, a marker of bacterial meningitis in children}; Bohuon C et al.; Procalcitonin (PCT) is a new marker connected to systemic bacterial infection . Blood values are parallel to the severity of the disease . In the present Knowledge on PCT, the usefulness is focused on acute pediatric pathology, ICU, and the follow up of grafts and surgery . This paper dwells on the interest in the differential diagnosis for meningitis (viral versus bacterial) . At the opposite of CRP and IL6, a very clear cut off for all the cases has been found . The cut off in this study is about 2-3 micrograms/l . PCT, at the difference of cytokines is a very stable molecule in the blood sample . Also a very small quantity of serum (or plasma) 20 microliters is sufficient for one assay . In the future, a point of care assay will be available and should be very interesting in the emergency wards (pediatric or adult ICU) . The origin of PCT seems to be--but perhaps not exclusively--mononuclear cells . The absence of an animal model (except monkeys) is actually a difficulty to progress. Mol Cells, 1998 Dec 31, 8(6), 691 - 7 Hepsulfam induced DNA adducts and its excision repair by bacterial and mammalian 3-methyladenine DNA glycosylases; Je KH et al.; A variety of alkylated base adducts are repaired by 3-methyladenine DNA glycosylases, one of the base excision repair enzymes . In this study, we examined the DNA adducts induced by hepsulfam and determined whether alkylated base adducts can be substrates for bacterial and mammalian 3-methyladenine DNA glycosylases by electrophoresis methods . Hepsulfam, a synthetic analogue of busulfan, is known to alkylate DNA and form interstrand cross-links . The extent of DNA interstrand cross-links induced by hepsulfam and busulfan was found to be similar but significantly lower than that induced by chlorambucil, as measured by an agarose gel assay . The major monofunctional alkylation site of hepsulfam was observed at the N7 position of guanine, and not at the N3 position of adenine . Both compounds did not exhibit any sequence selective DNA alkylation patterns . The excision of hepsulfam-induced DNA adducts has been determined by treatment with homogeneous recombinant bacterial, rat and human 3-methyladenine DNA glycosylases and successive treatments by formamidopyrimidine-DNA glycosylase . The Escherichia coli alkA protein was shown to completely excise N7 guanine adducts, whereas mammalian 3-methyladenine DNA glycosylase failed to excise them . In addition, the cytotoxicity assay showed that E . coli mutant strains defective in the alkA gene or the uvrA gene were more sensitive to killing by hepsulfam than the wild type. Biochimie, 1998 Oct, 80(10), 855 - 61 Bioaccumulation of heavy metals with protein fusions of metallothionein to bacterial OMPs; Valls M et al.; In view of potential biotechnological applications, eukaryotic metallothioneins (MTs) have been expressed in Escherichia coli as fusions to membrane or membrane-associated proteins such as LamB, the peptidoglycan-associated lipoprotein protein (PAL) or a hybrid Lpp/OmpA carrier sequence . The use of different anchors enables the MT moiety to be targeted into various cell compartments thus bringing the metal-binding ability of the resulting hybrids to specific sites of the cell structure . To this end, both full-size and partial sequences of the human or mouse MTs have been genetically fused to: i) the permissive site 153 of the LamB sequence, which loops out the MT to the external medium; ii) the N-terminus of a PAL variant devoid of its N-terminal cystein, which targets expression of the fusion into the periplasm; and iii) the C-terminus of Lpp-OmpA, for anchoring the MT to the outer membrane protein as an N-terminal fusion . Each type of fusion presented a distinct behavior in terms of expression, stability and ability to endow E . coli cells an enhanced accumulation of Cd2+, in good correlation with the number of metal-binding centers contributed by the MT moiety of the fusions . The expression in vivo of metalloproteins bound to bacterial envelope structures opens a way to design biomass with specific metal-binding properties. Curr Top Microbiol Immunol, 1999, 236, 215 - 36 Bacterial toxins as mucosal adjuvants; Freytag LC et al.; The use of mucosally administered killed bacteria or viruses as vaccines has a number of attractive features over the use of viable attenuated organisms, including safety, cost, storage and ease of delivery . Unfortunately, mucosally administered killed organisms are not usually effective as vaccines . The use of LT(R192G), a genetically detoxified derivative of LT, as a mucosal adjuvant enables the use of killed bacteria or viruses as vaccines by enhancing the overall humoral and cellular host immune response to these organisms, especially the Th1 arm of the immune response . With this adjuvant, protective responses equivalent to those elicited by live attenuated organisms can be achieved with killed organisms without the potential side effects . These findings have significant implications for vaccine development and further support the potential of LT(R192G) to function as a safe, effective adjuvant for mucosally administered vaccines . There are a number of unresolved issues regarding the use of LT and CT mutants as mucosal adjuvants . Both active-site and protease-site mutants of LT and CT have been constructed and adjuvanticity reported for these molecules in various animal models and with different antigens . There needs to be a side-by-side comparison of CT, LT, active-site mutants, protease-site mutants and recombinant B subunits regarding the ability to induce specific, targeted immunological outcomes as a function of route of immunization and nature of the co-administered antigen . Those side-by-side comparisons have not been carried out and there is a substantial body of evidence indicating that the outcomes may very well be different . With that information, vaccine strategies could be designed employing the optimum adjuvant/antigen formulation and route of administration for a variety of bacterial and viral pathogens . Also lacking is an understanding of the underlying cellular and intracellular signaling pathways activated by these different molecules and an understanding of the mechanisms of adjuvanticity at the cellular level . These are important issues because they take us beyond the phenomenological observations of "enhanced immunity" to a more clear understanding of the mechanisms of adjuvant activity. Anticancer Res, 1998 Nov-Dec, 18(6A), 4467 - 74 Enhancement of the cytolytic effect of anti-bacterial cecropin by the microvilli of cancer cells; Chan SC et al.; A comparison between IC50s of cecropin B on tumor cells such as KG-1 leukemia and Ags stomach carcinoma and non-tumor cells like fibroblasts and red blood cells was conducted . The IC50s of cecropin B for KG-1 leukemia and Ags carcinoma cells were 20.8 +/- 2.3 microM (MTT) and 18.9 +/- 3.3 microM (trypan blue) and 16.0 +/- 3.5 microM (MTT) & 15.3 +/- 3.7 microM (trypan blue), respectively . The IC50 of cecropin B for 3T6 fibroblast cells was 92.0 +/- 9.1 microM by MTT assay and the HE50 of cecropin B for human red blood cells was 180.0 +/- 20.1 microM at OD414nm . The cytolysis induced by cecropin peptides was more effective for the cancer cells than for the normal cells . Based on the observations from scanning electron microscopy, this may mainly due to the cancer cells having a high population of the irregular microvilli on the cell surface . Since peptides bound to the cell membrane are non-specific, the attraction of peptides by microvilli may be one of the main driving forces before the lysis in membrane bilayers can be efficiently initiated. Plant Cell Physiol, 1998 Nov, 39(11), 1240 - 4 Expression of bacterial chorismate pyruvate-lyase in tobacco: evidence for the presence of chorismate in the plant cytosol; Sommer S et al.; The bacterial gene ubiC encodes chorismate pyruvate-lyase, an enzyme which converts chorismate to 4-hydroxybenzoate and which is not normally present in plants . The UbiC protein was expressed in tobacco, with targeting of the gene product either to the plastids or to the cytosol . In both cases, chorismate pyruvate-lyase activity and a resulting formation of 4-hydroxybenzoate was detected . This suggests that chorismate, a metabolite of the shikimate pathway, is present not only in the plastids but also in the cytosol of plant cells. Biochemistry, 1999 Jan 5, 38(1), 390 - 8 Mutations in the environment of the primary quinone facilitate proton delivery to the secondary quinone in bacterial photosynthetic reaction centers; Valerio-Lepiniec M et al.; In Rhodobacter capsulatus, we constructed a quadruple mutant that reversed a structural asymmetry that contributes to the functional asymmetry of the two quinone sites . In the photosynthetically incompetent quadruple mutant RQ, two acidic residues near QB, L212Glu and L213Asp, have been mutated to Ala; conversely, in the QA pocket, the symmetry-related residues M246Ala and M247Ala have been mutated to Glu and Asp . We have selected photocompetent phenotypic revertants (designated RQrev3 and RQrev4) that carry compensatory mutations in both the QA and QB pockets . Near QA, the M246Ala --> Glu mutation remains in both revertants, but M247Asp is replaced by Tyr in RQrev3 and by Ala in RQrev4 . The engineered L212Ala and L213Ala substitutions remain in the QB site of both revertants but are accompanied by an additional electrostatic-type mutation . To probe the respective influences of the mutations occurring near the QA and QB sites on electron and proton transfer, we have constructed two additional types of strains . First, "half" revertants were constructed that couple the QB site of the revertants with a wild-type QA site . Second, the QA sites of the two revertants were linked with the L212Glu-L213Asp --> Ala-Ala mutations of the QB site . We have studied the electron and proton-transfer kinetics on the first and second flashes in reaction centers from these strains by flash-induced absorption spectroscopy . Our data demonstrate that substantial improvements of the proton-transfer capabilities occur in the strains carrying the M246Ala --> Glu + M247Ala --> Tyr mutations near QA . Interestingly, this is not observed when only the M246Ala --> Glu mutation is present in the QA pocket . We suggest that the M247Ala --> Tyr mutation in the QA pocket, or possibly the coupled M246Ala --> Glu + M247Ala --> Tyr mutations, accelerates the uptake and delivery of protons to the QB anions . The M247Tyr substitution may enable additional pathways for proton transfer that are located near QA. Pancreas, 1999 Jan, 18(1), 39 - 46 The effect of sennosides on bacterial translocation and survival in a model of acute hemorrhagic pancreatitis; Chen X et al.; Bacterial translocation leading to subsequent infectious complications is a significant determinant of outcome in acute hemorrhagic pancreatitis (AHP) . The colonic ileus and impaired intestinal barrier function that often accompany AHP may predispose to translocation . Sennoside is a naturally occurring cathartic and choleretic agent that stimulates intestinal mucous secretion and has potent promotility effects . The impact of sennoside-induced intestinal motility and secretory function on bacterial translocation and survival was studied in a rat model of AHP . Severe acute pancreatitis was induced in rats by the intraductal infusion of 2% sodium deoxycholate (DCA, 0.4 ml/kg) . A group of sham-operated rats (group A) received intraductal saline, whereas experimental animals were subsequently administered distilled water (group B) or sennoside solution (group C) by gavage every 8 h . After 48 h, intestinal transit of fluorescein isothiocyanate-labeled dextran, serum endotoxin, and amylase levels, and bacterial translocation to mesenteric lymph nodes (MLNs) and pancreatic tissue were determined . The pancreas and intestine were sampled for histologic study . All group A animals survived and did not develop pancreatitis or endotoxemia, whereas groups B and C all demonstrated severe hemorrhagic pancreatitis with evidence of necrosis . Mortality at 48 h was 55% in group B versus 12.5% in group C . Inhibition of intestinal motility was noted in 40% versus 20%, and endotoxin levels were 61.36+/-28.26 pg/L versus 5.41+/-3.58 pg/L in group B versus group C rats, respectively (p<0.001) . Pancreatic tissue and MLN cultures were positive in 100% of group B survivors versus 14% of group C survivors (p<0.05) . Histologic examination of the intestine in group C animals showed increased mucous secretion, proliferation of goblet cells, and evidence of rapid turnover/renewal of enterocytes . Treatment with the cathartic agent, sennoside, reduced translocation of endotoxin and bacteria, restored intestinal motility, increased mucous secretion, and reduced mortality in a model of acute hemorrhagic pancreatitis in the rat . Other cathartics may have similar properties and may be useful in preventing infectious complications in acute pancreatitis. Pneumologie, 1998 Nov, 52(11), 614 - 21 {Incidence of bacterial pneumonia in HIV-positive patients treated with preventive co-trimoxazole or pentamidine}; Koch A et al.; BACKGROUND: Besides Pneumocystis carinii bacterial pathogens represent the most common aetiology of pulmonary infections in HIV-positive patients . However, the impact of PCP prophylaxis on the incidence of bacterial pneumonia in HIV-positive patients using pentamidine or co-trimoxazole is still unknown . PATIENTS AND METHODS: We analysed retrospectively the data of 80 consecutive HIV-positive patients with a CD4-cell count < 300/microliter . The total observation period was 1993 patient months . Type and duration of chemoprophylaxis, frequency of bacterial pneumonia, PCP, extrapulmonary bacterial infections and cerebral toxoplasmosis were documented in a standardised manner . For statistical analysis we used the Kaplan-Meier test for the time to a recurrence of the various infections under both prophylaxis regimens and the Odds ratio for determination of the relative risk . RESULTS: We followed up 47 patients inhaling 300 mg pentamidine monthly for a total of 1133 months and 33 patients taking 480 mg co-trimoxazole per day p.o . for a total of 860 months . There were no statistically significant differences between the two groups in respect of demographic parameters, stage and therapy of HIV infection and distribution of risk groups . We found seven bacterial pneumonias in the co-trimoxazole group and 13 in the pentamidine group (not significant); the most common causative organisms were S . pneumoniae (n = 4), S . aureus (n = 3) and H . influenzae (n = 3) . Furthermore, in the pentamidine group 12 PCP and nine cases of toxoplasma encephalitis were observed, whereas none of these infections occurred in the co-trimoxazole group (p < 0.05) . Two of the patients taking co-trimoxazole and 15 of those inhaling pentamidine had extrapulmonary bacterial infections (p < 0.05), the most frequently identified pathogen being S . aureus (n = 7) . The two prophylaxis groups did not differ significantly with regard to laboratory data, course and therapy of the bacterial pneumonias . CONCLUSION: There was no significant influence of chemoprophylaxis on the incidence of bacterial pneumonia in patients with advanced HIV-disease in our study . Since S . pneumoniae represents the most common causative agent, we suggest immunisation with a polyvalent pneumococcal vaccine at an early stage of HIV-infection. DNA Cell Biol, 1998 Dec, 17(12), 1031 - 40 Bacterial expression and characterization of recombinant biologically active anti-tyrosine kinase receptor antibody forms; Peterson NC et al.; Homomeric and heteromeric interactions among cell-surface tyrosine kinase receptors belonging to the ErbB family lead to intracellular signaling cascades which are involved in cell activation, cytoskeletal interactions, and cellular transformation leading to neoplasia . Monoclonal antibodies which specifically bind to p185neu or epidermal growth factor receptor (EGFR), such as 7.16.4 and 225, respectively, can elicit tumor growth-inhibitory effects on transformed cells which overexpress either or both of these receptors . In order to better understand these receptor-receptor and receptor-antibody interactions and to gain insights that may be useful in the production and design of an antibody-based anticancer therapeutic, novel small recombinant 7.16.4 and 225 single-chain Fv fragments (scFv) were constructed, expressed, and characterized . We showed that these recombinant antibody fragments, which retain binding affinity, can be produced and purified from bacterial cell lysates . Our analyses further demonstrate that fusion of a 61 amino-acid dimerization domain with 7.16.4 and 225 scFv (7.16.4hth and 225hth) is sufficient to restore biological activity to these recombinant proteins. Microbiol Res, 1998 Nov, 153(3), 189 - 204 Heterologous expression of genes encoding bacterial light-harvesting complex II in Rhodobacter capsulatus and Rhodovulum sulfidophilum; Katsiou E et al.; In the present work we report the high-level expression of foreign genes encoding the light-harvesting (LHII) membrane-spanning polypeptides in photosynthetic bacteria . To do this we first constructed three deletion strains of Rhodovulum (Rhv.) sulfidophilum in which all or part of the puc operon, encoding the peripheral light-harvesting proteins, is missing . To investigate the heterologous expression of the light-harvesting polypeptides from Rb . capsulatus in Rhv . sulfidophilum and vice versa we have reintroduced functional foreign LH genes into these and equivalent strains of Rhodobacter (Rb.) capsulatus . In some cases very high levels of expression were obtained (85%) of those observed in the wild type), while in other cases much lower expression was observed; possible reasons for these differences are discussed . The heterologously expressed proteins were shown to contain normal pigment-binding sites and to be normally and functionally integrated within the host photosynthetic apparatus . The results indicate that heterologous proteins are able to assemble properly and enter into the same protein-protein interactions as their analogs originally present in the host strain. J Invertebr Pathol, 1999 Jan, 73(1), 113 - 9 Morphological description of bacterial infection of digestive glands in the terrestrial isopod porcellio scaber (Isopoda, crustacea) Drobne D, Strus J, Znidarsic N, Zidar P. Morphological studies of the hepatopancreas of the terrestrial isopod Porcellio scaber revealed bacterial infection . The percentage of infected animals collected from the same site varied from 0 to 10% during the 4 years of study . Transmission electron microscopy, scanning electron microscopy, and light microscopy revealed that infected glands differed from those in healthy isopods . The most prominent sign was white spots between 100 and 200 &mgr;m in diameter along the entire gland . These spots were aggregations of vacuoles in the cells that were densely filled with bacteria in different phases of the developmental cycle that included the formation of small, dense, rod-shaped infective bacteria and much larger spherical multiplying cells filled with aggregates of polysomes and a chromatin network . Occasionally, large sphericles were filled with homogeneous electron-dense material . Bacteria were not observed in the cell nucleus . Small vacuoles of less than 5 &mgr;m were filled predominately with spherical bacteria but rod-shaped forms were also present in large numbers . Larger vacuoles of 10 to 20 &mgr;m in the main were densely filled with rod-shaped bacteria . According to the literature on the morphological characteristics of bacteria infecting invertebrates, those described in our study would be classified in the genus Rickettsiella . However, most recent investigations show that besides morphological investigations, genetic ones are also needed to define the taxonomic position of bacteria that infect invertebrates . Vet Immunol Immunopathol, 1998 Dec 11, 66(3-4), 301 - 7 The release of tumor necrosis factor-alpha, interleukin-1, interleukin-6 and prostaglandin E2 in bovine Kupffer cells stimulated with bacterial lipopolysaccharide; Yoshioka M et al.; Kupffer cells, in response to gut-derived bacteria, viruses and endogenous endotoxins, are thought to be a major source of proinflammatory cytokines and other mediators . In the present study, we investigated the mode of tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1), interleukin-6 (IL-6) and prostaglandin E2 (PGE2) production by bovine Kupffer cells in response to LPS in vitro . By semi-quantitative reverse transcription-polymerase chain reaction, both TNF-alpha and IL-1beta mRNAs were expressed between 3 and 12 h after stimulation with 1 microg/ml of LPS . The IL-1alpha transcript also increased at 3 h, and then disappeared at 6 h . Although IL-6 mRNA was slightly expressed without stimulation, it increased and reached a peak after 6 h, and then decreased to normal levels by 24 h . The secretion of TNF-alpha and IL-1 was detected after 3 h and increased until 12 and 24 h, respectively, as detected by bioassay . IL-6 was secreted at a low level without stimulation, peaked 6 h after stimulation and remained elevated until 24 h . The secretion of prostaglandin E2 continued to increase for 24 h . These results suggest that several inflammatory cytokines released from bovine Kupffer cells are regulated in different modes. FEMS Immunol Med Microbiol, 1998 Dec, 22(4), 317 - 27 A commensal symbiosis between Prevotella bivia and Peptostreptococcus anaerobius involves amino acids: potential significance to the pathogenesis of bacterial vaginosis; Pybus V et al.; In both batch and continuous culture, Peptostreptococcus anaerobius was able to grow in vaginal defined medium with Prevotella bivia, but not in pure culture . Growth of P . anaerobius was increased by 238% (P < 0.001) in peptone-supplemented vaginal defined medium conditioned by prior growth of P . bivia . Analysis of P . bivia culture supernatants showed a net accumulation of amino acids and subsequent growth of P . anaerobius in the conditioned supernatants resulted generally in amino acid utilization . Supplementation of peptone-supplemented vaginal defined medium with amino acids in concentrations similar to those available after prior growth with P . bivia were growth-stimulatory (246%, P=0.006) for P . anaerobius . Increased availability of amino acids by P . bivia is proposed as a mechanism to support the observed in vitro commensal symbiosis between P . bivia and P . anaerobius. Appl Environ Microbiol, 1999 Jan, 65(1), 319 - 21 Bacterial leaching of metal sulfides proceeds by two indirect mechanisms via thiosulfate or via polysulfides and sulfur Schippers A, Sand W. The acid-insoluble metal sulfides FeS2, MoS2, and WS2 are chemically attacked by iron(III) hexahydrate ions, generating thiosulfate, which is oxidized to sulfuric acid . Other metal sulfides are attacked by iron(III) ions and by protons, resulting in the formation of elemental sulfur via intermediary polysulfides . Sulfur is biooxidized to sulfuric acid . This explains leaching of metal sulfides by Thiobacillus thiooxidans. Hum Gene Ther, 1998 Dec 10, 9(18), 2787 - 94 Herpes simplex virus type 1 DNA amplified as bacterial artificial chromosome in Escherichia coli: rescue of replication-competent virus progeny and packaging of amplicon vectors; Saeki Y et al.; Herpes simplex virus type 1 (HSV-1)-based amplicon vectors contain only approximately 1% of the 152-kb HSV-1 genome, and consequently, replication and packaging into virions depends on helper functions . These helper functions have been provided conventionally by a helper virus, usually a replication-defective mutant of HSV-1, or more recently, by a set of five cosmids that overlap and represent the genome of HSV-1 deleted for DNA cleavage/packaging signals (pac) . In the absence of pac signals, potential HSV-1 genomes that are reconstituted from the cosmids via homologous recombination are not packageable . The resulting amplicon stocks are, therefore, virtually free of contaminating helper virus . To simplify this packing system, the HSV-1 genome was cloned and maintained stably as a single-copy, F plasmid-based bacterial artificial chromosome in E . coli . Such a plasmid containing the HSV-1 genome deleted for the pac signals (fHSV delta pac) did not generate replication-competent progeny virus on transfection into mammalian cells, but rather, it was able to support the packaging of cotransfected amplicon DNA that contained a functional pac signal . The resulting amplicon vector stocks had titers of up to 10(7) transducing units per milliliter of culture medium and efficiently transduced neural cells in the rat brain, as well as hepatocytes in the rat . The capacity of generating infectious and replication-competent HSV-1 progeny following transfection into mammalian cells was restored after insertion of a pac signal into fHSV delta pac. Eur J Biochem, 1998 Dec 1, 258(2), 768 - 74 Molecular cloning and bacterial expression of a general odorant-binding protein from the cabbage armyworm Mamestra brassicae; Maibeche-Coisne M et al.; A cDNA clone encoding a general odorant-binding protein (GOBP2) was isolated from antennal RNA of Mamestra brassicae by reverse transcription-PCR (RT-PCR) and RACE-PCR . The cDNA encoding the GOBP2 was further used for bacterial expression . Most of the recombinant GOBP2 (>90%) was found to be insoluble . Purification under denaturing conditions consisted of solubilisation of inclusion bodies, affinity chromatography, refolding and gel filtration . The refolded rGOBP2 was cross-reactive with a serum raised against the GOBP2 of the Lepidoptera Antheraea polyphemus . The purified refolded rGOBP2 was further characterised by native PAGE, IEF, N-terminal sequencing, and two-dimensional NMR . A functional characterisation of the rGOBP2 was carried out by testing its ability to bind pheromone compounds . The yields of production and purification fulfil the requirements of structural studies. Acta Microbiol Immunol Hung, 1998, 45(3-4), 401 - 8 Advance in bacterial typing methods (a review); Milch H; We give a short review about the two main groups of bacterial typing methods for epidemiological purposes: the phenotypic and genotypic methods . The advantage of the phenotypic methods is their feasibility for the less equipped laboratories, their disadvantages are the variability of the phenotypic properties, and their high labor requirement . The advantages of the genotypic typing methods are the higher discriminatory power and applicability of the same method for different species of bacteria . The disadvantage of these methods is that they are expensive and labour consuming . Beside the short description, we show the results of different authors obtained by the use of the molecular methods in the epidemiological practice and we call the attention to the insufficiency concerning the stability. Bioorg Med Chem Lett, 1998 Jul 7, 8(13), 1643 - 8 Inhibitors of the bacterial cell wall biosynthesis enzyme MurD; Gegnas LD et al.; A series of transition-state analog inhibitors of the D-glutamic acid-adding enzyme (MurD) of bacterial peptidoglycan biosynthesis has been synthesized and evaluated for inhibition of the E . coli enzyme. Anal Chem, 1998 Dec 15, 70(24), 5296 - 301 Estimation of bacterial contamination in ultrapure water: application of the anti-DNA antibody; Nogami T et al.; We constructed and established a hybridoma cell line that produces immunoglobulin G-type anti-DNA antibody . By using this antibody, we could successfully detect a single bacterial cell in ultrapure water (UPW) . The detection system is composed of a membrane-supported western blotting-type immunoassay and a two-dimensional photon analyzer with high resolution . It can detect and count every bacterial cell in a wide field of view on a trapping filter i.e., a circle with an 18-mm diameter . This means 10 fg (10(-14) g) of bacterial DNA can be detected in the field . This system could be a useful tool for evaluating the number of bacteria contained by UPW and water used for medical purposes. Arch Surg, 1998 Dec, 133(12), 1351 - 5 Hemorrhage exacerbates bacterial translocation at low levels of intra-abdominal pressure; Gargiulo NJ 3rd et al.; BACKGROUND: It has been shown previously that the adverse cardiopulmonary sequelae of increased intra-abdominal pressure (IAP) are worsened by hemorrhage and resuscitation . Bacterial translocation (BT) to the mesenteric lymph nodes (MLNs), liver, and spleen has also been shown to occur with increased IAP . OBJECTIVE: To investigate the hypothesis that BT associated with elevated IAP would be significantly increased after hemorrhage and resuscitation . MATERIALS AND METHODS: Anesthetized adult male rats had femoral artery and vein catheters placed, and an intra-abdominal catheter placed to measure IAP . Group 1 underwent surgery only and served as controls . Group 2 had IAP raised to 10 mm Hg by infused lactated Ringer's solution for 40 minutes . Group 3 had a 25% hemorrhage, followed by resuscitation by infused lactated Ringer's solution and shed blood . Group 4 first had a 25% hemorrhage, resuscitated using infused lactated Ringer's solution and shed blood, and then had IAP raised to 10 mm Hg by infused lactated Ringer's solution for 40 minutes . All groups were killed after 2 hours, and had MLNs, liver, and spleen harvested for quantitative cultures . RESULTS: Hemorrhage and resuscitation alone did not increase BT to the MLNs, liver, or spleen . An increase in IAP to 10 mm Hg resulted in a significant level of BT to the MLNs and liver on MacConkey II agar (P<.05), and a significant increase in the level of BT only to the liver on trypticase soy agar with 5% sheep's blood (P<.05) . Hemorrhage and resuscitation did increase the level of BT to the liver and spleen when IAP was increased to 10 mm Hg (P<.05) . CONCLUSIONS: In this model, hemorrhage and resuscitation alone did not increase BT to the MLNs, liver, or spleen . However, hemorrhage and resuscitation increased BT to the liver and spleen when IAP was increased to 10 mm Hg . This supports the concept that prior hemorrhage and resuscitation exacerbates the effects of increased IAP. Biochemistry (Mosc), 1998 Nov, 63(11), 1277 - 81 Effects of medium viscosity on kinetics of the enzymatic reaction catalyzed by bacterial RNase Stupishina EA, Vershinina VI VI. Effects of medium viscosity on kinetic parameters of poly(U) hydrolysis catalyzed by RNase from Bac . intermedius 7P (binase) were studied in solutions of sucrose (4-50 wt . %) and glycerol (35-62 wt . %) in Tris--sodium acetate buffer (pH 7.5) at 25 degreesC . The rate constant of reaction kcat was practically unchanged over a wide range of viscosities (1-15 cP for sucrose and 2.5-3 cP for glycerol) . In glycerol solutions, kcat slightly increased with viscosity increase from 4 to 10 cP . Addition of NaCl to the buffer medium resulted in an inhibitory effect of Na+ on kcat, prevented by 50% sucrose or 60% glycerol . It is concluded that binase-catalyzed poly(U) cleavage occurs through a "tense"-substrate mechanism, similarly to reactions catalyzed by alpha-chymotrypsin, trypsin, and laccase. Lett Appl Microbiol, 1998 Oct, 27(4), 235 - 8 Computerized evaluation procedure for comparing the electrophoretic protein patterns of bacterial strains; Bernath S et al.; The advantages and drawbacks of different methods of evaluating electrophoretic (SDS-PAGE) protein patterns were studied by comparing Erysipelothrix rhusiopathiae strains . The computerized evaluation procedure recommended by the authors renders it possible to determine objectively the degree of similarity of the protein composition of the different strains according to molecular mass . The degree of similarity obtained in four parallel analyses of a given strain was 988 +/- 0.55 on a scale on which 1000 equals complete identity . the method can be used without adjustment even in those cases where the two strains to be compared contain unequal amounts of electrophoresed proteins. Int J STD AIDS, 1998 Nov, 9(11), 683 - 8 Mannose-binding protein in HIV-seropositive patients does not contribute to disease progression or bacterial infections; McBride MO et al.; This study set out to investigate whether plasma mannose-binding protein (MBP) deficiency caused by mutations in the MBP gene associates with pyogenic or opportunistic infections in HIV-infected patients . Plasma samples were selected randomly from 131 HIV-infected patients followed prospectively for a period not exceeding 12 months or until death . Plasma MBP concentrations were measured by an ELISA and genotyping was determined by amplification of exon 1 of the MBP gene by polymerase chain reaction (PCR) technology, followed by restriction enzyme analysis and Southern blotting using sequence-specific oligonucleotide probes . Neither MBP concentration nor genotype was found to associate with disease progression or opportunistic infection rate . There was an unexpected increased bacterial infection rate in patients with MBP levels greater than 100 ng/ml and wild type genotype . Thus, MBP does not appear to play a role in HIV infection . MBP is an acute phase reactant and this may explain the higher levels in those with more frequent pyogenic infections. Placenta, 1998 Nov, 19(8), 625 - 30 Interleukin-1beta and bacterial endotoxin change the metabolism of prostaglandins E2 and F2alpha in intact term fetal membranes; Brown NL et al.; There is strong evidence that prostaglandins E2 and F2alpha (PGE2 and PGF2alpha) are involved in the initiation and maintenance of human parturition and that their production can be stimulated by a number of cytokines and in infection-induced preterm labour by bacterial endotoxin . This study used an intact fetal membrane disk model to investigate the regulation of PGE2 and PGF2alpha metabolism by interleukin-1 beta (IL-1beta) and bacterial endotoxin {lipopolysaccharide (LPS)} . Fetal membrane explants were incubated with IL-1beta (0.1 or 1.0 ng/ml) or LPS (10 ng/ml) for 24 h . A mixture of 3H-prostaglandin (0.1 microCi) and unlabelled prostaglandin (1 microg) was then added at selected times after the addition of inflammatory mediators . The radiolabelled prostaglandins and their metabolites were then extracted from the culture medium and quantified by high-pressure liquid chromatography . Levels of prostaglandin metabolites were generally decreased following incubation with IL-1beta or LPS, which is consistent with a decrease in the activity of 15-hydroxyprostaglandin dehydrogenase (PGDH) . It is concluded that IL-1beta and LPS moderately decrease the metabolism of prostaglandins, which may contribute to increasing the local levels of active prostaglandins induced by these stimuli. J Biol Chem, 1998 Dec 25, 273(52), 35371 - 80 Bacterial lipopolysaccharide disrupts endothelial monolayer integrity and survival signaling events through caspase cleavage of adherens junction proteins; Bannerman DD et al.; Bacterial lipopolysaccharide or endotoxin induces actin reorganization, increased paracellular permeability, and endothelial cell detachment from the underlying extracellular matrix in vitro . We studied the effect of endotoxin on transendothelial albumin flux and detachment of endothelial cells cultured on gelatin-impregnated filters . The endotoxin-induced changes in endothelial barrier function and detachment occurred at doses and times that were compatible with endotoxin-induced apoptosis . Since the actin cytoskeleton and cell-cell and cell-matrix adhesion all participate in the regulation of the paracellular pathway and cell-matrix interactions, we studied whether protein components of the actin-linked adherens junctions were modified in response to endotoxin . Components of cell-cell (beta- and gamma-catenin) and cell-matrix (focal adhesion kinase and p130(Cas)) adherens junctions were cleaved by caspases activated during apoptosis with dose and time requirements that paralleled those seen for barrier dysfunction and detachment . Cleavage of focal adhesion kinase led to its dissociation from the focal adhesion-associated signaling protein, paxillin, resulting in reduced paxillin tyrosine phosphorylation . Inhibition of caspase-mediated cleavage of these proteins protected against detachment but not opening of the paracellular pathway . Therefore, endotoxin-induced disruption of endothelial monolayer integrity and survival signaling events is mediated, in part, through caspase cleavage of adherens junction proteins. J Anim Sci, 1998 Nov, 76(11), 2905 - 11 Effect of ruminal cellulolytic bacterial concentrations on in situ digestion of forage cellulose; Dehority BA et al.; To evaluate the effects of ruminal cellulolytic bacterial concentrations on in vivo cellulose digestion, varying percentages of flaked soybean hulls were substituted for orchardgrass hay in high-forage diets fed to sheep . In two experiments, total and cellulolytic ruminal bacterial concentrations were not affected by diet . No differences were found for in situ digestion of forage cellulose in the first experiment; however, in Exp . 2, ruminal pH and in situ cellulose digestion were lower (P<.01) with a 40% soybean hull diet . In Exp . 3 with four sheep, two diets were compared, one containing 19.6% cellulose from alfalfa meal and the other 64.3% purified wood cellulose . Ruminal pH was lower (P<.02), 9 and 24 h after feeding, for the high-cellulose diet . Total bacterial concentrations did not change with diet; however, the concentration of cellulolytic bacteria increased (P<.05) when the higher cellulose diet was fed . In situ cellulose digestion was not different between diets . In Exp . 4, 3% sodium bicarbonate was added to the high-cellulose diet, and it was fed twice a day . No differences were observed in pH between diets (P>.42) . However, the concentration of total ruminal bacteria increased (P<.06), the concentration of cellulolytic bacteria increased (P<.03), and the percentage of cellulolytic bacteria increased (P<.04) when the buffered high-cellulose diet was fed . In situ digestion of alfalfa cellulose at 30 h was not different between diets (P>.60) . These data indicate that the concentration of cellulolytic bacteria is not the limiting factor in the digestion of cellulose in the rumen. J Endod, 1998 Nov, 24(11), 763 - 7 Bacterial reduction with nickel-titanium rotary instrumentation; Dalton BC et al.; The purpose of this study was to compare intracanal bacterial reduction on teeth instrumented with 0.04 tapered nickel-titanium (NiTi) rotary instrumentation to bacterial reduction when using a stainless-steel K-file step-back technique using sterile saline irrigation . Forty-eight patients with apical periodontitis were randomly assigned treatment type . The canals were sampled before, during, and after instrumentation . The samples were incubated anaerobically for 7 days at 37 degrees C, colony-forming unit numbers calculated, and a log transformation performed to normalize the counts . Teeth exhibiting apical periodontitis were uniformly infected, whereas vital control teeth were not . A similar and uniform reduction occurred with progressive filing, regardless of technique (p < 0.0001) . There was no detectable difference in colony-forming unit count after NiTi rotary or stainless-steel hand instrumentation (p = 0.42) . Neither technique could predictably render canals free of bacteria . The results of this study indicate NiTi rotary and stainless-steel hand K-file step-back instrumentation techniques were not significantly different in their ability to reduce intracanal bacteria. Am J Obstet Gynecol, 1998 Dec, 179(6 Pt 1), 1579 - 82 Preterm labor and bacterial intraamniotic infection: arachidonic acid liberation by phospholipase A2 of Fusobacterium nucleatum; Mikamo H et al.; OBJECTIVE: The studies presented in this report were undertaken to evaluate whether Fusobacterium nucleatum, a common anaerobic isolate in intrauterine infection, stimulates arachidonic acid metabolism, a rate-limiting step for prostaglandin synthesis, in the human uterine endometrium . STUDY DESIGN: Effects of F nucleatum on arachidonic acid liberation from human uterine endometrial cells and of F nucleatum extract on lysophosphatidylcholine production in human uterine endometrial cells were investigated . RESULTS: When human uterine endometrial cells labeled with tritiated arachidonic acid to an isotopically steady state were exposed to an extract of F nucleatum, arachidonic acid liberation was stimulated, accompanied by lysophospholipid formation . Similar stimulatory effects on phospholipid degradation were also observed in the experiment with bacterially conditioned media . CONCLUSIONS: These results suggest that F nucleatum stimulates endometrial phospholipid metabolism, related to activity of phospholipase A2, which might induce the onset of labor associated with intraamniotic infection. Neurology, 1998 Dec, 51(6), 1710 - 4 Lumbar and ventricular CSF protein, leukocytes, and lactate in suspected bacterial CNS infections; Gerber J et al.; Protein concentration, leukocyte density, and lactate concentration were studied in 41 pairs of ventricular and lumbar CSF drawn at an interval of less than 24 hours from patients with suspected bacterial CNS infections . The ventriculo-lumbar ratios ranged from 0.003 to 10.2 (median=0.42) for protein and from 0.002 to 53.5 (median=0.17) for leukocytes . The uneven distribution of leukocytes and proteins in the CSF space may produce findings that fail to indicate bacterial CNS infections . Lactate was distributed more homogeneously in the CSF space than protein and leukocytes (ventriculo-lumbar ratio 0.52 to 1.66 {median=0.811). Dev Biol Stand, 1998, 95, 25 - 9 Review of current preclinical testing strategies for bacterial vaccines; Falk LA et al.; A wide variety of bacterial vaccines is in various stages of preclinical and clinical development . These products range from whole killed or live attenuated bacterial organisms to purified proteins, peptides and plasmid DNA . Although preclinical strategies may be directed by a set of common guidelines focused on demonstrating safety and biological activity, the exact developmental scheme will depend on product-specific characteristics . In general, preclinical data should support the proposed clinical formulation and include detailed information on the source and quality of starting materials, manufacturing processes, characterization of bacterial seed stocks, potency, general safety, purity, and identity . Data describing product validation and testing may be appropriate depending on the type of product, e.g., genetic stability for recombinant constructs, details on inactivation or attenuation methods for organisms or toxins, demonstration of potency of combination products, and safety and toxicology studies of plasmid DNA vaccines or vaccines with novel adjuvants . The choice of dose, route, and formulation to be used clinically may be greatly affected by rigorous preclinical developmental strategies. Med Klin (Munich), 1998 Oct 15, 93(10), 612 - 8 {Spontaneous bacterial peritonitis}; Zundler J et al.; BACKGROUND: Since the beginning of the eighties systematic investigations broadened our knowledge about the clinical picture of spontaneous bacterial peritonitis very much . Important insights into epidemiology, pathogenesis, symptomatology, diagnosis and therapy of this disease, which is a frequent complication in patients with cirrhosis of the liver and ascites, could be gained . Actual research work primarily deals with questions of therapy and prophylaxis . AIM: Aim of this review is a comprehensive presentation of the different aspects of this disease on the basis of the present literature . CONCLUSIONS: As on the one side the clinical symptoms may be very little and on the other side the prognosis is very bad, it is extremely important to take this entity into the differential considerations to make an early diagnosis and to start an adequate therapy early. Gene, 1998 Oct 9, 221(1), 143 - 9 Cloning, bacterial synthesis, and characterization of immunoglobulin variable regions of a monoclonal antibody specific for the hepatitis B virus X protein; zu Putlitz J et al.; The nucleotide (nt) sequences encoding the variable regions of the heavy (H) and light (L) chains were determined for a murine monoclonal antibody, 12/231/93, which is specific for a linear epitope located between amino acids 90 and 102 of the hepatitis B virus (HBV) X protein (HBx) . The variable (V) regions of the H and L chains were shown to belong to the mouse H chain subgroup II (C) and kappa L chain group III, respectively . The cloned variable region sequences were used for the production of a Fab fragment in Escherichia coli, which had binding activity for membrane immobilized recombinant HBx . These gene sequences may be useful for the study of HBx function in cells that will support HBV replication. J Hum Genet, 1998, 43(4), 255 - 8 Isolation and mapping of a novel human kidney- and liver-specific gene homologous to the bacterial acetyltransferases; Ozaki K et al.; Using the differential display method to detect tissue-specific genes, we isolated a novel human gene, designated TSC501, that is expressed in kidney and liver . The cDNA contained an open reading frame of 681 nucleotides encoding 227 amino acids . The predicted product showed homologies in amino acid sequence to three different bacterial acetyltransferases, enzymes that are involved in drug resistance . Radiation hybrid mapping localized this gene to human chromosome bands 2p12-p13.1. Microb Ecol, 1998 Nov, 36(3), 316 - 327 Growth Rates of Bacterial Communities in Soils at Varying pH: A Comparison of the Thymidine and Leucine Incorporation Techniques; Baath E; Abstract The growth rate of bacteria in 19 soils with pH values ranging from 4 to 8 was determined using the thymidine (TdR) and leucine (Leu) incorporation techniques . The variation in isotope dilution and unspecific incorporation was also studied . The mean Leu incorporation into protein was 45% of the incorporation into total macromolecules, and was not affected by soil pH . TdR incorporation into DNA varied between 5 and 20% of that into total macromolecules, with the lowest values in the low-pH soils . Isotope dilution plots for Leu incorporation were linear . This was not the case for TdR incorporation, indicating non-Michaelis-Menten kinetics . The degree of participation (DP) of the added labeled compound in Leu incorporation varied between 0.4 (in low-pH soils) and 0.7 and was directly affected by pH . DP for TdR incorporation varied more (from 0.1 to 1), with the lowest values in the low-pH soils . The variation in DP in TdR incorporation was, however, not directly affected by pH . Calculated bacterial turnover times at 20 degreesC varied between 2.3 and 33 days (mean 9.3 days) using TdR incorporation data, and between 2.1 and 13.1 days (mean 5.9 days) using Leu incorporation data . Turnover times were longer for bacteria in low-pH soils, calculated using the Leu incroporation data, while no effect from pH was found using the TdR incorporation data . Comparing data from aquatic habitats indicated that bacterial growth rates in soil were lower. Microb Ecol, 1998 Nov, 36(3), 270 - 280 Interactions of Photobleaching and Inorganic Nutrients in Determining Bacterial Growth on Colored Dissolved Organic Carbon; Reche I I et al.; Abstract Bacteria are key organisms in the processing of dissolved organic carbon (DOC) in aquatic ecosystems . Their growth depends on both organic substrates and inorganic nutrients . The importance of allochthonous DOC, usually highly colored, as bacterial substrate can be modified by photobleaching . In this study, we examined how colored DOC (CDOC) photobleaching, and phosphorus (P) and nitrogen (N) availability, affect bacterial growth . Five experiments were conducted, manipulating nutrients (P and N) and sunlight exposure . In almost every case, nutrient additions had a significant, positive effect on bacterial abundance, production, and growth efficiency . Sunlight exposure (CDOC photobleaching) had a significant, positive effect on bacterial abundance and growth efficiency . We also found a significant, positive interaction between these two factors . Thus, bacterial use of CDOC was accelerated under sunlight exposure and enhanced P and N concentrations . In addition, the accumulation of cells in sunlight treatments was dependent on nutrient availability . More photobleached substrate was converted into bacterial cells in P- and N-enriched treatments . These results suggest nutrient availability may affect the biologically-mediated fate (new biomass vs respiration) of CDOC. Microb Ecol, 1998 Nov, 36(3), 259 - 269 Bacterial Abundance and Activity across Sites within Two Northern Wisconsin Sphagnum Bogs; Fisher MM et al.; Abstract Bacterial abundance, temperature, pH, and dissolved organic carbon (DOC) concentration were compared across surface sites within and between two northern Wisconsin Sphagnum peatlands over the summer seasons in 1995 and 1996 . Sites of interest were the Sphagnum mat surface, the water-filled moat (lagg) at the bog margin, and the bog lake littoral zone . Significant differences in both bacterial populations and water chemistry were observed between sites . pH was highest in the lake and lowest in the mat at both bogs; the opposite was true for DOC . Large populations of bacteria were present in surface interstitial water from the mat; abundance in this site was consistently higher than in the moat or lake . Bacterial abundance also increased across sites of increasing DOC concentration and declining pH . Bacterial activities (rates of {3H}leucine incorporation) and growth in dilution cultures (with grazers removed) were also assessed in lake, moat, and mat sites . Results using these measures generally supported the trends observed in abundance, although high rates of {3H}leucine incorporation were recorded in the moat at one of the bogs . Our results indicate that bacterial populations in Sphagnum peatlands are not adversely affected by acidity, and that DOC may be more important than pH in determining bacterial abundance in these environments. Ugeskr Laeger, 1998 Nov 30, 160(49), 7105 - 8 {Normocellular bacterial meningitis}; Lindberg JA; Bacterial meningitis is usually associated with pleocytosis of the cerebrospinal fluid due to the presence of polymorphonuclear leucocytes . However, 75 cases of bacterial meningitis without pleocytosis have been published . Normocellular bacterial meningitis accounts for 3.5% (1-42%) of all patients suffering from bacterial meningitis and is seen in all age groups: The finding can be explained by three different mechanisms including 1) lumbar puncture performed early in the course of meningitis, 2) immune deficiency, and 3) relative leucopenia due to severe sepsis . Normocellular bacterial meningitis is in general associated with a good prognosis except for cases with severe underlying diseases . A high concentration of bacteria in a normocellular cerebrospinal fluid might also indicate a poor prognosis. J Periodontol, 1998 Nov, 69(11), 1193 - 202 Early bacterial accumulation on guided tissue regeneration membrane materials . An in vivo study; Zucchelli G et al.; The aim of the study was to compare the in vivo early bacterial plaque colonization of 3 different guided tissue regeneration (GTR) membrane materials using a morphological (scanning electron microscope) method . Rectangular-shaped strips were cut from 3 periodontal membranes (expanded polytetrafluoroethylene, polyglactin 910, and polylactic acid) and glued to the buccal aspect of removable acrylic devices, which were applied to the molar-premolar region of the upper quadrants in 8 dental students . Each device held 3 strips: one ePTFE, one polyglactin 910, and one polylactic acid . The surface roughness of each membrane material was measured by means of a laser profilometer . During a 24-hour period, the students had to refrain from any oral hygiene procedures and did not use chlorhexidine mouthrinses . In each subject, one device was removed after 4 hours and the other after 24 hours . After removal, the devices were placed in a 2.5% gluteraldehyde solution to fix the membranes, which were then processed for SEM analysis . Fifty-four microscopic fields (at 200x magnification) were randomly selected and analyzed in each strip . Magnification was increased to determine the presence of bacterial morphotypes . The presence or absence of bacteria was assessed in a binomial fashion . In such a system, the field was bacteria-positive when bacteria constituted the deposits covering the surface of the membrane . The microscopic field was considered bacteria-negative when no bacteria were present . Bacteria-positive fields showing rods and filaments as prevalent bacterial morphotypes were recorded as rod-positive fields . A different pattern of plaque accumulation was demonstrated on different membrane materials . The 4-hour results indicated a statistically significant difference (P = 0.008, ANOVA) in the proportion of bacteria-positive fields among the 3 membranes; a greater amount of bacteria was demonstrated on the ePTFE membrane compared to the other 2 membranes . At 24 hours, the difference in the proportion of bacteria-positive fields was statistically significant (P = 0.002, ANOVA); a lesser amount of bacterial plaque was present on the polylactic acid membrane compared to the ePTFE and polyglactin 910 membranes . No difference in the proportion of rod/bacteria-positive fields was demonstrated among the 3 membranes at either 4 or 24 hours . It was concluded that quantitative differences in early plaque accumulation on various membranes seem to be related to the textural and structural characteristics of the surface, which is not adequately represented by the surface Ra value measured with a profilometric instrument. Nurs Stand, 1998 Sep 23-29, 13(1), 37 - 42 Bacterial contamination of nurses' uniforms: a study; Callaghan I; This study examined the hypothesis that the wearing of plastic aprons during direct patient contact would reduce significantly the number of bacteria carried on nurses' uniforms, and therefore reduce the probability of the transmission of nosocomial infections . Current nursing practices and overall bacterial uniform contamination levels were investigated, as well as the effects of the wearing of plastic aprons to protect uniforms . The conclusions of the study demonstrate that such contamination may be significant contributory factor in the spread of nosocomial infections, and have implications not only for the nursing profession, but also for other members of the multidisciplinary team . In next week's Nursing Standard, the author examines the difficulties of putting research into practice. Genome Res, 1998 Nov, 8(11), 1154 - 71 How to interpret an anonymous bacterial genome: machine learning approach to gene identification; Hayes WS et al.; In this report we address the problem of accurate statistical modeling of DNA sequences, either coding or noncoding, for a bacterial species whose genome (or a large portion) was sequenced but not yet characterized experimentally . Availability of these models is critical for successful solution of the genome annotation task by statistical methods of gene finding . We present the method, GeneMark-Genesis, which learns the parameters of Markov models of protein-coding and noncoding regions from anonymous bacterial genomic sequence . These models are subsequently used in the GeneMark and GeneMark.hmm gene-finding programs . Although there is basically one model of a noncoding region for a given genome, several models of protein-coding region are automatically obtained by GeneMark-Genesis . The diversity of protein-coding models reflects the diversity of oligonucleotide compositions, particularly the diversity of codon usage strategies observed in genes from one and the same genome . In the simplest and the most important case, there are just two gene models-typical and atypical ones . We show that the atypical model allows one to predict genes that escape identification by the typical model . Many genes predicted by the atypical model appear to be horizontally transferred genes . The early versions of GeneMark-Genesis were used for annotating the genomes of Methanoccocus jannaschii and Helicobacter pylori . We report the results of accuracy testing of the full-scale version of GeneMark-Genesis on 10 completely sequenced bacterial genomes . Interestingly, the GeneMark.hmm program that employed the typical and atypical models defined by GeneMark-Genesis was able to predict 683 new atypical genes with 176 of them confirmed by similarity search. Toxicology, 1998 Sep 1, 130(1), 17 - 28 Delayed febrile effects of chlorpyrifos: is there cross-tolerance to bacterial lipopolysaccharide? Gordon CJ, Rowsey PJ. Oral chlorpyrifos (CHP) induces hypothermia followed by a fever that persists for several days in the rat . To understand the neuro-immune mechanisms of CHP-induced fever, we compared the tolerance and cross-tolerance between CHP and the fever elicited by lipopolysaccharide (LPS) (Escherichia coli) . Female rats were administered the corn oil (CO) vehicle or CHP (10 mg/kg; p.o.) daily for 4 days while core temperature (Tc) and motor activity (MA) were monitored by telemetry . There was a reduction in Tc followed by an elevation the next day after each CHP treatment . The day after the last CHP treatment, rats were administered saline or 50 microg/kg LPS (i.p.) . CHP-treated rats had a smaller LPS fever that was attributed to their elevated baseline Tc . In another study, rats were dosed with saline or LPS daily for three days . By the time of the third LPS injection there was no febrile response, indicating tolerance to LPS . Rats were then dosed with CO or CHP (10 mg/kg) 24 h after the third LPS treatment . LPS-tolerant rats displayed an accentuated hypothermic and febrile response to CHP . Plasma cholinesterase activity was unaffected by repeated LPS treatment, suggesting that the metabolism of CHP in the liver was unaffected by LPS . Overall, the neural-immune mechanisms for LPS fever is distinct from that of CHP in view of marked difference in mechanisms of tolerance. Eur J Obstet Gynecol Reprod Biol, 1998 Oct, 80(2), 231 - 4 The frequency of bacterial and yeast infection in women with different grades of cervical intraepithelial neoplasia (CIN); Takac I; OBJECTIVE: To determine bacterial and yeast infection of the uterine cervix in women with different grades of cervical intraepithelial neoplasia (CIN) . STUDY DESIGN: 578 patients with CIN were included in this study . In order to determine the presence of bacterial and yeast infection, a cervical swab was obtained before conization of the uterine cervix . After surgery and the definitive histology report, the frequency of bacterial and yeast infection in different grades of CIN was calculated . RESULTS: Among 578 patients with CIN, bacterial or yeast infection was present in 379 (65.6%) patients . In patients with CIN 1, infection was present in 20 (71.4%), in CIN 2 in 106 (69.7%) and in CIN 3 in 252 (63.3%) cases . The differences in the frequency of infection among all three groups are not significant . CONCLUSION: In patients with CIN bacterial and yeast infection of the uterine cervix is very common . Its occurrence does not depend on the grade of CIN. Trends Microbiol, 1998 Nov, 6(11), 454 - 9 Presentation of bacterial lipid antigens by CD1 molecules; Prigozy TI et al.; Human CD1 molecules bind and display or present lipid and glycolipid antigens from mycobacteria for recognition by T cells . Presentation requires uptake of antigen into endosomes, where it binds to CD1 . T-cell recognition of CD1-presented nonpeptide antigens is a newly defined immune response that could be important for host defense against a variety of pathogens. No To Hattatsu, 1998 Nov, 30(6), 494 - 9 {Seizures in the acute phase of aseptic and bacterial meningitis}; Inoue S et al.; We studied seizures that occur during the acute phase of aseptic and bacterial meningitis in childhood . Of the 108 children with aseptic meningitis, five had seizures (4.7%) . Four patients developed them within 24 hours of the onset of the initial symptom (fever in 3 cases), and three had repeated seizures on the first day . One case had SIADH complication, but another neurologic abnormalities were not observed . On the 18 children with bacterial meningitis, three cases (16.7%) had seizure, which occurred on the second day of illness . Disturbance of consciousness and cerebral hypertension were observed in 2 cases each, and abnormal cerebral CT findings in all the three . The NSE level in the cerebrospinal fluid was elevated in 2 cases . Thus, seizures occurring in the acute phase of aseptic meningitis may reflect transient cerebral functional abnormality accompanying fever or SIADH, whereas those in bacterial meningitis may result from neural tissue damage due to encephalopathy or angitis . In aseptic and bacterial meningitis, the presence of seizures in the acute phase was not correlated with the neurological outcome. Proc Natl Acad Sci U S A, 1998 Dec 8, 95(25), 14652 - 7 Upstream A-tracts increase bacterial promoter activity through interactions with the RNA polymerase alpha subunit; Aiyar SE et al.; Upstream A-tracts stimulate transcription from a variety of bacterial promoters, and this has been widely attributed to direct effects of the intrinsic curvature of A-tract-containing DNA . In this work we report experiments that suggest a different mechanism for the effects of upstream A-tracts on transcription . The similarity of A-tract-containing sequences to the adenine- and thymine-rich upstream recognition elements (UP elements) found in some bacterial promoters suggested that A-tracts might increase promoter activity by interacting with the alpha subunit of RNA polymerase (RNAP) . We found that an A-tract-containing sequence placed upstream of the Escherichia coli lac or rrnB P1 promoters stimulated transcription both in vivo and in vitro, and that this stimulation required the C-terminal (DNA-binding) domain of the RNAP alpha subunit . The A-tract sequence was protected by wild-type RNAP but not by alpha-mutant RNAPs in footprints . The effect of the A-tracts on transcription was not as great as that of the most active UP elements, consistent with the degree of similarity of the A-tract sequence to the UP element consensus . A-tracts functioned best when positioned close to the -35 hexamer rather than one helical turn farther upstream, similar to the positioning optimal for UP element function . We conclude that A-tracts function as UP elements, stimulating transcription by providing binding site(s) for the RNAP alphaCTD, and we suggest that these interactions could contribute to the previously described wrapping of promoter DNA around RNAP. J Exp Med, 1998 Dec 7, 188(11), 2091 - 7 Human toll-like receptor 2 confers responsiveness to bacterial lipopolysaccharide; Kirschning CJ et al.; Bacterial lipopolysaccharide (LPS) induces activation of the transcription factor nuclear factor kappaB (NF-kappaB) in host cells upon infection . LPS binds to the glycosylphosphatidylinositol (GPI)- anchored membrane protein CD14, which lacks an intracellular signaling domain . Here we investigated the role of mammalian Toll-like receptors (TLRs) as signal transducers for LPS . Overexpression of TLR2, but not TLR1, TLR4, or CD14 conferred LPS inducibility of NF-kappaB activation in mammalian 293 cells . Mutational analysis demonstrated that this LPS response requires the intracellular domain of TLR2 . LPS signaling through TLR2 was dependent on serum which contains soluble CD14 (sCD14) . Coexpression of CD14 synergistically enhanced LPS signal transmission through TLR2 . In addition, purified recombinant sCD14 could substitute for serum to support LPS-induced TLR2 activation . LPS stimulation of TLR2 initiated an interleukin 1 receptor-like NF-kappaB signaling cascade . These findings suggest that TLR2 may be a signaling component of a cellular receptor for LPS. Shock, 1998 Nov, 10(5), 319 - 23 Genetic component in the inflammatory response induced by bacterial lipopolysaccharide; De Maio A et al.; Multiple organ dysfunction syndrome (MODS) appears to be the result of a complex program influenced by multiple factors, including environmental, physiological, and immunological conditions . Thus, an uncontrolled inflammatory response following a stochastic event, the initial injury, is believed to be the cause for the development of this syndrome . Several lines of evidence suggest that a genetic component could contribute to the regulation of the inflammatory response, as well, but no direct evidence demonstrates a heritable predisposition to MODS . In the present study, a genetic contribution was demonstrated for the inflammatory response induced by the administration of bacterial lipopolysaccharide (LPS) in different, genetically distinct strains of inbred mice . A survey of five inbred strains showed that mortality following administration of Escherichia coli LPS (20 mg/kg) was highest in C57BL/6J (B6) mice, while A/J mice were the most resistant . Accordingly, B6 and A/J mice were examined further for differences in the inflammatory response elicited by LPS . B6 mice showed higher levels of circulating interleukin-1beta and interleukin-6, as well as higher mRNA levels of hepatic beta-fibrinogen (an acute-phase gene) and metallothionein . Surprisingly, the circulating levels of tumor necrosis factor-alpha were significantly higher in A/J than in B6 mice after LPS administration . Since B6 and A/J mice were bred and raised in identical environments and received the same LPS challenge, the contrasting inflammatory response that was observed is largely attributable to genetic differences between these two strains . These data illustrate that the response to injury could be modulated by the genetic background of the individual . This information may be pertinent for the care of critically ill patients. Mediators Inflamm, 1998, 7(1), 19 - 23 Abnormal directed migration of blood polymorphonuclear leukocytes in rheumatoid arthritis . Potential role in increased susceptibility to bacterial infections; Aglas F et al.; Rheumatoid arthritis (RA) patients are at higher risks of bacterial infection than healthy subjects . Polymorphonuclear leukocytes (PMN) are the first line of nonspecific cellular defence against these infections . We tested the hypothesis that abnormal directed migration of PMN may be one reason for the increased infection rate of RA patients . PMN migration was investigated in 68 peripheral blood samples of 15 RA patients compared with 64 samples of healthy controls in a novel whole blood in vitro membrane filter assay . The migration of PMNs from RA patients and controls was stimulated using the bacterial chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMLP) . Unstimulated PMN migration of RA patients was increased compared with healthy controls as measured by the following parameters: (a) absolute number of migrant PMNs (1954+/-87 vs . 1238 +/-58 PMN/mm2), (b) percentage of PMNs migrated into the filter (total migration index, TMI) (28.6+/-0.9 vs . 24.0+/-0.8%), (c) the distance half the migrating PMNs had covered (distribution characteristic, DC) (22.6+/-1.1 vs . 16.1+/-0.6 mm) and (d) the product of TMI and DC (neutrophil migratory activity, NMA) (669.0+/-45.0 vs . 389.0+/-18.9) . fMLP stimulated PMNs of RA patients showed defective migration compared to unstimulated samples as shown by (a) a reduced number of migrant PMNs (1799+/-93 PMN/mm2), (b) lower TMI (26.1+/-0.9%), (c) unremarkable altered distribution characteristic (22.9+/-0.8 mm) and (d) significant reduced migratory activity (600.0+/-30.0) . Our data suggest that the high incidence of infections in RA patients may partly be caused by defective migratory activity of PMNs to bacterial chemoattractants as demonstrated by fMLP. J Biolumin Chemilumin, 1998 Sep-Oct, 13(5), 287 - 93 Ultraweak light emission is a common response of bacterial cells to chemico-physical stress; Maccarrone M et al.; Escherichia coli JM101 cells were subjected to pore-forming electric fields, irradiation with ultraviolet light or oxidative stress by either the lipoxygenase products 9- and 13-hydroperoxyoctadecadienoic acids (9- and 13-HPOD) or hydrogen peroxide . It was found that all chemico-physical stresses enhanced ultraweak light emission from the bacterial cells, the most effective treatment being electroporation (up to 20-fold increase in luminescence compared to the control value), followed by oxidative stress with 9- or 13-HPOD (up to 4-fold increase) and irradiation with UV light (up to 2.8-fold increase) . Bacterial luminescence was always in the red edge of the spectrum and was paralleled by changes in membrane oxidative index and specific activity of catalase and superoxide dismutase. J Mol Biol, 1998 Dec 11, 284(4), 1191 - 9 Regulation of phosphatase activity in bacterial chemotaxis; Blat Y et al.; Bacterial chemotaxis is the most studied model system for signaling by the widely spread family of two-component regulatory systems . It is controlled by changes in the phosphorylation level of the chemotactic response regulator, CheY, mediated by a histidine kinase (CheA) and a specific phosphatase (CheZ) . While it is known that CheA activity is regulated, via the receptors, by chemotactic stimuli, the input that may regulate CheY dephosphorylation by CheZ has not been found . We measured, by using stopped-flow fluorometry, the kinetics of CheZ-mediated dephosphorylation of CheY . The onset of dephosphorylation was delayed by approximately 50 ms after mixing phosphorylated CheY (CheY approximately P) with CheZ, and a distinct overshoot was observed in the approach to the new steady state of CheY approximately P . The delay and overshoot were not observed in a hyperactive mutant CheZ protein (CheZ54RC) that does not support chemotaxis in vivo and appears to be constitutively active . CheZ activity was cooperative with respect to CheY approximately P, with a Hill-coefficient of 2.5 . The observed delayed modulation of CheZ activity and its cooperativity suggest that the phosphatase activity is regulated at the level of CheY approximately P-CheZ interaction . This novel kind of interplay between a response regulator and its phosphatase may be involved in signal tuning and in adaptation to chemotactic signals . J Mol Biol, 1998 Dec 11, 284(4), 1005 - 15 In vitro replication of mitochondrial plasmid mp1 from the higher plant Chenopodium album (L.): a remnant of bacterial rolling circle and conjugative plasmids? Backert S, Kunnimalaiyaan M, Borner T, Nielsen BL. According to the endosymbiotic theory, mitochondrial genomes evolved from the chromosome of an alpha-proteobacterium-like ancestor and developed during evolution an extraordinary variation in size, structure and replication . We studied in vitro DNA replication of the mitochondrial circular plasmid mp1 (1309 bp) from the higher plant Chenopodium album (L.) as a model system that replicates in a manner reminiscent of bacterial rolling circle plasmids . Several mp1 subclones were tested for their ability to support DNA replication using a newly developed in vitro system . Neutral/neutral two-dimensional gel electrophoresis of the in vitro products revealed typical simple Y patterns of intermediates consistent with a rolling circle type of replication . Replication activity was very high for a BamHI-restricted total plasmid DNA clone, a 464 bp BamHI/KpnI fragment and a 363 bp BamHI/SmaI fragment . Further subcloning of a 148 bp BamHI/EcoRI fragment resulted in the strongest in vitro DNA replication activity, while a 1161 bp-template outside of this region resulted in a substantial loss of activity . Electron microscopic studies of in vitro DNA replication products from the highly active clones also revealed sigma-shaped molecules . These results support our in vivo data for the presence of a predominant replication origin between positions 628 and 776 on the plasmid map . This sequence shares homology with double-stranded rolling circle origin (dso) or transfer origin (oriT) nicking motifs from bacterial plasmids . mp1 is the first described rolling circle plasmid in eukaryotes . J Theor Biol, 1998 Dec 21, 195(4), 481 - 504 Mathematical models for motile bacterial transport in cylindrical tubes; Chen KC et al.; Mathematical models considering motile bacterial transport within a geometrically restrictive cylindrical tube were developed . Two macroscopic transport parameters, the random motility coefficient as a self-diffusion coefficient of the cell population and the chemotactic velocity as a chemical-induced velocity, were derived . The three-dimensional cell balance equation was reduced to forms similar to Segel's one-dimensional phenomenological cell balance equations with additional modifications for bacteria-wall interactions . Two conceptually different approaches accounting for such interactions were presented . The first approach parallels treatments in the gas kinetic theory by viewing bacterial interactions with walls as collisions and subsequent diffusive/specular reflections, which led to the Bosanquet formula for the bacterial diffusion coefficient . Based on the experimental observation that bacterial swimming motion is guided by a straight tube, the second approach considered modifications in the bacterial swimming orientation as a consequence of various long-range interactions with the tube surface . A phenomenological turning model capable of aligning bacterial motion along a tube axis was proposed . The model predicts that under the geometrical restriction of a small cylindrical tube, the macroscopic bacterial transport resulting from the proposed turning model can exhibit behavior that ranges from dimensionally reduced diffusion to pure wave propagation, depending on the influence of the tube diameter on the reversal probability in the bacterial swimming motion . Our theoretical model provides explicit equations that explain how such a transition can occur . The predicted results were then qualitatively compared with experimental data from the literature . As a preliminary comparison, we concluded that bacterial transport in cylindrical tubes of diameter 10 micrometers remains in the mode of a dimensionally reduced diffusion, and shifts to a wave motion when the tube diameter decreases to 6 micrometers . Appl Environ Microbiol, 1998 Dec, 64(12), 5046 - 8 Changes in bacterial species composition in enrichment cultures with various dilutions of inoculum as monitored by denaturing gradient gel electrophoresis; Jackson CR et al.; Denaturing gradient gel electrophoresis revealed changes in the bacterial species obtained from enrichment cultures with different inoculum dilutions . This inoculum dilution enrichment approach may facilitate the detection and isolation of a greater number of bacterial species than traditional enrichment techniques. Pediatrics, 1998 Dec, 102(6), 1364 - 8 Otoacoustic emissions as a screening test for hearing impairment in children recovering from acute bacterial meningitis; Richardson MP et al.; OBJECTIVES: To study the efficacy of otoacoustic emissions (OAEs) as a screening test for hearing impairment in children with acute bacterial meningitis . Hearing tests were performed before discharge from the hospital in an attempt to improve coverage and avoid delays in the diagnosis of postmeningitic hearing loss . METHODS: Children with bacterial meningitis were recruited from 21 centers . In the 48 hours before discharge from the hospital, all patients underwent a thorough audiologic assessment consisting of transient evoked OAEs, auditory brainstem responses (ABRs), otoscopy, and tympanometry . Hearing loss was defined as ABR threshold >/=30 dB . The results of OAE screening were compared with the gold standard of ABR threshold . RESULTS: Of 124 children recruited, we were able to perform both OAEs and ABRs on 110 children . Seven (6.3%) of the 110 children had ABR threshold >/=30 dB; 2 had sensorineural hearing loss and 5 had conductive hearing loss . At follow-up, hearing loss persisted in both cases of sensorineural hearing loss and no new cases were identified . All 7 children with hearing loss failed the OAE screening test . Ninety-four children with normal hearing thresholds passed the test, and 9 failed . Thus, the screening test had a sensitivity of 1.00 (95% confidence interval, 0.59 to 1.00), a specificity of 0.91 (0.85 to 0.97), a positive predictive value of 0 . 44 (0.20 to 0.70), and a negative predictive value of 1.00 (0.96 to 1.00) . CONCLUSIONS: OAE screening in children recovering from meningitis was found to be feasible and effective . The test was highly sensitive and reasonably specific . Inpatient OAE screening should allow early diagnosis of postmeningitic hearing loss and prompt auditory rehabilitation. Mem Inst Oswaldo Cruz, 1998 Sep-Oct, 93(5), 581 - 5 Molecular epidemiologic typing systems of bacterial pathogens: current issues and perspectives; Struelens MJ; The epidemiologic typing of bacterial pathogens can be applied to answer a number of different questions: in case of outbreak, what is the extent and mode of transmission of epidemic clone(s)? In case of long-term surveillance, what is the prevalence over time and the geographic spread of epidemic and endemic clones in the population? A number of molecular typing methods can be used to classify bacteria based on genomic diversity into groups of closely-related isolates (presumed to arise from a common ancestor in the same chain of transmission) and divergent, epidemiologically-unrelated isolates (arising from independent sources of infection) . Ribotyping, IS-RFLP fingerprinting, macrorestriction analysis of chromosomal DNA and PCR-fingerprinting using arbitrary sequence or repeat element primers are useful methods for outbreak investigations and regional surveillance . Library typing systems based on multilocus sequence-based analysis and strain-specific probe hybridization schemes are in development for the international surveillance of major pathogens like Mycobacterium tuberculosis . Accurate epidemiological interpretation of data obtained with molecular typing systems still requires additional research on the evolution rate of polymorphic loci in bacterial pathogens. Biotech Histochem, 1998 Sep, 73(5), 278 - 88 Cationized ferritin as a stain for electron microscopic observation of bacterial ultrastructure; Anderson KL; The electron microscope has proven very effective for visualization of various morphological features of bacteria . Cationized ferritin (CF) is a stain commonly used to increase the electron microscopic resolution of bacterial cells, thereby enabling detailed analysis of their morphological and structural features . CF has been useful for microscopic examination of the bacterial capsule, cell wall, S-layer, and various unique morphological structures . In addition, as a cation, CF binds only to negatively charged molecules . Thus, CF has been used to identify sites of anionic charge on the bacterial cell surface, which has led to insights concerning the formation and turnover of bacterial peptidoglycan and the S-layer proteins . As a cation, however, CF may also interact with certain cellular components, causing erroneous interpretation of microscopic results . This review provides a discussion of both the strengths and weaknesses of CF when used as a stain for electron microscopy. Mol Microbiol, 1998 Nov, 30(3), 459 - 66 Stimulus response coupling in bacterial chemotaxis: receptor dimers in signalling arrays; Levit MN et al.; In the Escherichia coli chemotaxis system, a family of chemoreceptors in the cytoplasmic membrane binds stimulatory ligands and regulates the activity of an associated histidine kinase CheA to modulate swimming behaviour and thereby cause a net migration towards attractants and away from repellents . The chemoreceptors themselves have been shown to be predominantly dimeric, but in the presence of the kinase CheA plus an adapter protein, CheW, much higher order structures have been observed . Recent results indicate that transmembrane signalling occurs within receptor clusters rather than through isolated dimers . We propose that the mechanism involves receptor arrays where binding of ligands at the outside surface of the membrane affects lateral packing interactions that cause perturbations in the organization of the signalling array at the opposing surface of the membrane . Results with receptor chimeras as well as findings with tyrosine kinase receptors suggest that this mechanism may represent a common theme in membrane receptor function. Toxicol Lett, 1998 Aug, 96-97, 335 - 9 The use of YG bacterial tester strains for the monitoring of drinking water mutagenicity; Cerna M et al.; The organic extract from the 50 drinking water specimens taken in four cities were tested for mutagenicity in the Ames test (plate incorporation assay) using the parent TA98 and TA100 strains, and derived YG1041 and YG1042 strains . Four dose levels of extractable organic matter (EOM) with duplicate plate per dose were used . Slopes (revertants/mg EOM) were calculated by the Bernstein linear regression rejection model using GeneTox Manager software . The mutagenicity observed in the conventional strains TA98 and TA100 did not reach the significant increase in all tested samples with the higher mutagenic response found in TA100-S9 . With the YG1041 and YG1042 tester strains, the results obtained demonstrated the clear-cut direct dose-related mutagenicity response in all tested drinking water extracts . Compared with TA98 and TA100 strains, the numbers of YG induced revertants were approximately 20 times higher . The high sensitivity of the YG tester strains could facilitate the mutagenicity monitoring in drinking water extracts, and help reduce the volume of sample required . However, to identify the chemical contaminants in drinking water responsible for the mutagenicity further studies are required. Am J Gastroenterol, 1998 Nov, 93(11), 2226 - 30 Steatorrhea and weight loss in a 72-year-old man: primary biliary cirrhosis? Celiac disease? Bacterial overgrowth? What else? DiBaise JK, Paustian FF. Unintentional weight loss is an ominous sign, particularly when it occurs in the elderly; concern for malignancy is especially worrisome . In this report, we describe a 72-yr-old man who presented with weight loss and was found to have massive steatorrhea . An extensive evaluation revealed evidence of primary biliary cirrhosis (PBC), celiac disease, and small intestinal bacterial overgrowth . No malignancy was identified . The weight loss was attributed to severe steatorrhea due, in part, to intraluminal bile salt deficiency, small bowel mucosal disease, and bacterial overgrowth . Several points are discussed regarding gastrointestinal function in elderly patients with chronic liver disease secondary to PBC . The rare association between PBC and celiac disease in adults is also discussed . Finally, we suggest that bacterial overgrowth plays a significant role in the development of steatorrhea in some persons with PBC and that an assessment for bacterial overgrowth should be performed on persons with steatorrhea and PBC. Urol Nefrol (Mosk), 1998 Sep-Oct, (5), 20 - 2 {Treatment results in chronic bacterial prostatitis using radio waves}; Agadzhanian VV et al.; We report the results of examination, treatment and follow-up of 30 patients aged 25-40 years with chronic bacterial prostatitis . We used the method of local transurethral hyperthermia of the prostate ("Thermex" unit) . This method proved effective as the period of remission in comparison with standard conservative therapy increased 2-3-fold . This treatment is indicated in patients with longstanding inflammatory process and in patients suffering from prostatitis with secondary disorders of potency. J Clin Lab Immunol, 1997, 49(1), 33 - 40 Effects of age on neutrophil function and its relevance to bacterial infections in the elderly; Angelis P et al.; OBJECTIVE: To determine the effect of age on neutrophil function in patients with and without acute bacterial infections . METHOD: Four groups of patients were recruited: Group 1: 15 elderly patients with infection (mean age 80.4 +/- 1.9 years), Group 2: 15 elderly control patients without infection (mean age 81.1 +/- 2.2 years), Group 3: 8 young patients with infections (mean age 26.7 +/- 2.9 years) and Group 4: 23 young controls (mean age 27.6 +/- 0.9 years) . The main outcome measures included neutrophil counts and respiratory burst activation as measured by luminol enhanced chemiluminescence . RESULTS: Mean neutrophil counts were significantly higher in young patients with infections (5.04 +/- 0.96 x 10(9)/L) compared with young controls (2.63 +/- 0.33 x 10(9)/L) (p = 0.008) and in elderly with infections (6.51 +/- 0.97 x 10(9)/L) compared with elderly controls (4.1 +/- 0.88 x 10(9)/L) (p = 0.046) . There was no significant difference between neutrophil counts of old and young patients (p = 0.40) or controls (p = 0.16) . Mean peak luminol chemiluminescence was significantly increased in young patients (3329 +/- 284 mV) compared with young controls (1398 +/- 108 mV) and in elderly patients (2994 +/- 219 mV) compared with elderly controls (1674 +/- 197 mV) (p < 0.001) . There was no significant difference between chemiluminescence activities of young and elderly controls (p = 0.41) or young and elderly patients (p = 0.14) . CONCLUSION: Age is not associated with a change in neutrophil number or activity in the absence of bacterial infection . Infection in both young and elderly produces a significant increase in neutrophil number and chemiluminescence activity. J Infect, 1998 Jan, 36(1), 63 - 6 Correlation of leucocyte count and erythrocyte sedimentation rate with the day of illness in presumed bacterial pneumonia of childhood; Triga MG et al.; We investigated the effect of the duration of illness on the white blood cell (WBC) and total neutrophil counts and the erythrocyte sedimentation rate (ESR) in untreated children with clinical and roentgenographic findings compatible with bacterial pneumonia . According to the duration of illness before admission, the patients were divided into: Group I, 48 patients ill for < 24 h; Group II, 39 patients ill for 24-48 h; Group III, 21 patients ill for 48-72 h; and Group IV, eight patients ill for 72-96 h . In children with presumably bacterial pneumonia the number of the WBC was greater during the first 2 days of illness . Thereafter, the leucocyte count declined, reaching the lowest levels on the fourth day . A similar course was followed by the absolute number of total neutrophils . During the second day of illness, 92% and 72% of the patients had leucocyte counts > 10,000 and > 15,000/mm3, respectively, whereas on the fourth day of illness only half of the patients had > 10,000 and one-quarter > 15,000 WBC/mm3 . The ESR followed an opposite course to that of the WBC . During the first day of illness it was normal or mildly elevated, increasing steadily thereafter . The validity of the WBC and total neutrophil counts in conjunction with the ESR in the evaluation of bacterial pneumonia is augmented when the day of illness is taken into consideration. Scand J Clin Lab Invest, 1998 Aug, 58(5), 383 - 93 C-reactive protein and bacterial meningitis: a meta-analysis; Gerdes LU et al.; The aim of the study was to review published articles on the diagnostic accuracy of C-reactive protein (CRP) tests with cerebrospinal fluid and serum in diagnosing bacterial meningitis . The literature from 1980 and onwards was searched using the electronic databases of MEDLINE, and we used summary receiver operating characteristic curve analyses (SROCs) to describe central tendencies and examine possible sources of inter-study variability in the results . We included data from 35 studies of both children and adults: 21 in which CRP had been measured in cerebrospinal fluid, 10 in which CRP had been measured in serum, and 4 in which it had been measured in both cerebrospinal fluid and serum . The odds ratio for bacterial meningitis versus aseptic meningitis for a positive CRP test with cerebrospinal fluid was estimated at 241 (95% confidence interval {CI}: 59-980), and the central tendencies for the true-positive fraction (sensitivity) and the false-positive fraction (1-specificity) were estimated at 0.94 and 0.06, respectively . The corresponding figures for a CRP test with serum were 150 (95% CI: 44-509), 0.92 and 0.08, respectively . Regression analyses including variables coding for study design features, inclusion of neonatal patients, geographical region, or use of a quantitative biochemical method did not indicate statistically significant contributions to inter-study variances in the log odds ratios . For values of the true- and the false-positive fractions of 0.92-0.94 and 0.06-0.08, respectively, the post-test probability of not having bacterial meningitis given a negative test is very high (> or = 97%), in the range of a pre-test probability (prevalence of bacterial meningitis) from 10 to 30%, whereas the post-test probability of bacterial meningitis given a positive test is considerably lower . Hence, only a negative test is highly informative in a typical clinical setting . This, as well as the absence of analyses to show if CRP tests contribute independent diagnostic information, relatively to the information held in the traditionally used clinical and biochemical variables, makes it difficult to conclude on the clinical usefulness of CRP tests in the management of patients suspected of having bacterial meningitis. J Infect Dis, 1998 Dec, 178(6), 1698 - 706 Impairment of the mucosal immune system: IgA and IgM cleavage detected in vaginal washings of a subgroup of patients with bacterial vaginosis; Cauci S et al.; The integrity of the immunoglobulins in vaginal washings of patients with bacterial vaginosis was examined to answer the question of the lack of immune response against Gardnerella vaginalis cytolysin . Clinically diagnosed patients (n=100) were recruited and their vaginal washings examined by Western blotting . Many showed IgA and IgM partially or extensively degraded . According to the degradation pattern, the patients were subdivided into 4 subsets, from intact (score 0) to completely degraded IgA (score +3) . Statistical analysis of the data showed a correlation between IgA degradation and absence of immune response to G . vaginalis cytolysin . The extent of IgA degradation correlated also with the sialidase (but not with the prolidase) activity level . All women showed intact IgG and human serum albumin and no trypsin-like activity . Patients with bacterial vaginosis having high sialidase activity and extensive IgA degradation in their secretions could incur more dangerous infections and adverse pregnancy outcomes. Plant Cell Physiol, 1998 Sep, 39(9), 899 - 904 Cloning and bacterial expression of sesquiterpene cyclase, a key branch point enzyme for the synthesis of sesquiterpenoid phytoalexin capsidiol in UV-challenged leaves of Capsicum annuum; Back K et al.; Sesquiterpene cyclase, a branch point enzyme in the general isoprenoid pathway for the synthesis of phytoalexin capsidiol, was induced in detached leaves of Capsicum annuum (pepper) by UV treatment . The inducibility of cyclase enzyme activities paralleled the absolute amount of cyclase protein(s) of pepper immunodetected by monoclonal antibodies raised against tobacco sesquiterpene cyclase . A cDNA library was constructed with poly(A)+ RNA isolated from 24 h UV-challenged leaves of pepper . A cDNA clone for sesquiterpene cyclase in pepper was isolated by using a tobacco 5-epi aristolochene synthase gene as a heterologous probe . The predicted protein encoded by this cDNA was comprised of 559 amino acids and had a relative molecular mass of 65,095 . The primary structural information from the cDNA clone revealed that it shared 77%, 72% and 49% identity with 5-epi aristolochene, vetispiradiene, and cadinene synthase, respectively . The enzymatic product catalyzed by the cDNA clone in bacteria was identified as 5-epi aristolochene, as judged by argentation TLC . RNA blot hybridization demonstrated the induction of an mRNA consistent with the induction of cyclase enzyme activity in UV-treated pepper. Clin Cancer Res, 1995 Nov, 1(11), 1359 - 68 Retroviral transfer of a bacterial alkyltransferase gene into murine bone marrow protects against chloroethylnitrosourea cytotoxicity; Harris LC et al.; The chloroethylnitrosoureas (CENUs) are important antineoplastic drugs for which clinical utility has been restricted by the development of severe delayed myelosuppression in most patients . To investigate the potential of DNA repair proteins to reduce bone marrow sensitivity to the CENUs, we transferred the Escherichia coli ada gene, which encodes a Mr 39,000 O6-alkylguanine-DNA alkyltransferase (ATase), into murine bone marrow cells by the use of a high-titer ecotropic retrovirus . The ada-encoded ATase is resistant to O6-benzylguanine (O6-BG), a potent inhibitor of the mammalian ATases, thus affording the bone marrow an additional level of protection against CENUs . In methylcellulose cultures, ada-infected hematopoietic progenitor cells were twice as resistant as uninfected cells to the toxic effects of 1, 3-bis(2-chloroethyl)-1-nitrosourea (BCNU) following treatment with O6-BG . Although showing no obvious protective effects against leukopenia, overexpression of the bacterial ATase activity reduced the severity of anemia and thrombocytopenia in mice treated with O6-BG and BCNU . These effects, which were maximal at a BCNU dose of 12.5 mg/kg, were associated with improved survival when BCNU was given at this dose . At lower BCNU doses cytotoxicity was limited in both transduced and control mice, and at higher doses the protective effect was saturated due to cytotoxicity . These results suggest that ada gene therapy may be a feasible approach to amelioration of delayed myelosuppression following O6-BG plus CENU combination chemotherapy. Clin Cancer Res, 1997 Feb, 3(2), 301 - 7 Retroviral transfer of a bacterial alkyltransferase gene (ada) into human bone marrow cells protects against O6-benzylguanine plus 1, 3-bis(2-chloroethyl)-1-nitrosourea cytotoxicity; Marathi UK et al.; The antitumor activity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) is limited by the O6-alkylguanine-DNA alkyltransferase (ATase) in tumor cells and by delayed myelosuppression . Inactivation of neoplastic ATase by O6-benzylguanine (BG) improves the therapeutic index for BCNU . We have demonstrated previously that BG + BCNU-induced myelosuppression in mice is reduced by expression of the BG-resistant ATase ada in murine bone marrow . We have now generated an amphotropic retrovirus containing the ada gene and tested the effectiveness of ada expression in preventing BG + BCNU cytotoxicity in human hematopoietic progenitor cells . A retroviral producer clone with a biological titer of 6.5 x 10(4) colony-forming units/ml and 4.4 pmol ATase/mg protein was used for transduction of bone marrow . Cocultivation of these ada producer cells with progenitor cells from six normal individuals resulted in 1.9-3 . 9-fold protection against BG + BCNU-induced cytotoxicity in committed progenitor cell assays . Furthermore, this cytoprotective effect was associated with a high transduction efficiency (40%) and a 2-fold increase of ATase activity in the surviving committed progenitor cell colonies . These data provide a basis for testing the clinical effectiveness of retroviral ada gene transfer into hematopoietic cells to increase the therapeutic index of BG + BCNU. Arq Gastroenterol, 1998 Apr-Jun, 35(2), 110 - 5 Significance of bacterial translocation in nutrition; Waitzberg DL et al.; Considerable progress has been made during the last decade in the understanding of the pathophysiology of sepsis and multiple organ dysfunction syndrome . Gut-derived sepsis has been recognized as an important etiology of multiple organ dysfunction syndrome . Bacterial translocation of indigenous intestinal flora to the systemic circulation has been postulated as an important etiology of gut-derived sepsis . In this paper, we review the fundamental aspects of bacterial translocation as mechanism of disease, and the influence of nutritional support . Critical animal and human data are presented and discussed, and emphasis is given to its potential clinical applications. Med Sci Sports Exerc, 1998 Nov, 30(11), 1561 - 3 Bacterial osteitis pubis in a weight lifter without invasive trauma; Combs JA; Osteitis pubis is a well-known complication of invasive procedures about the pelvis which is caused by a bacterial infection . It is also now known that osteitis pubis in athletes is an inflammatory disorder rather than infectious as previously thought . It occurs in athletes who place significant repetitive stresses across the symphysis in such activities as running, race walking, gymnastics, soccer, rugby, basketball, and tennis . This case report, however, describes a weight lifter who developed a bacterially caused osteitis pubis without any invasive trauma . He was evaluated thoroughly and no other focus of infection was found . He was treated conservatively with intravenous antibiotics and physical therapy . At 3 months follow-up he had returned to his usual fitness activities without limitations . Although most osteitis pubis in athletes is inflammatory in nature, health care providers must keep an index of suspicion that an infectious etiology is possible in this population even without invasive trauma. J Wildl Dis, 1998 Oct, 34(4), 834 - 8 Serosurvey of selected viral and bacterial diseases in wild swine from Oklahoma; Saliki JT et al.; Blood samples collected from 120 wild swine (Sus scrofa) in thirteen Oklahoma (USA) counties during 1996 were tested for antibodies against six viral and two bacterial diseases . No antibodies to swine brucellosis, pseudorabies, transmissible gastroenteritis, and vesicular stomatitis were detected . Antibody titers to one or more leptospiral serovars were found in 44% of the samples, the two most frequent serovars being Leptospira interrogans serovars bratislava (29%) and pomona (27%) . Antibody against porcine parvovirus and swine influenza virus was detected in 17% and 11% of the swine, respectively . Two samples (2%) were positive for antibody to the recently emerged porcine reproductive and respiratory syndrome virus. J Mol Biol, 1998 Nov 27, 284(2), 401 - 19 The crystal structure of 8-amino-7-oxononanoate synthase: a bacterial PLP-dependent, acyl-CoA-condensing enzyme; Alexeev D et al.; 8-Amino-7-oxononanoate synthase (or 8-amino-7-ketopelargonate synthase; EC 2.3.1.47; AONS) catalyses the decarboxylative condensation of l-alanine and pimeloyl-CoA in the first committed step of biotin biosynthesis . We have cloned, over-expressed and purified AONS from Escherichia coli and determined the crystal structures of the apo and PLP-bound forms of the enzyme . The protein is a symmetrical homodimer with a tertiary structure and active site organisation similar to, but distinct from, those of other PLP-dependent enzymes whose three-dimensional structures are known . The critical PLP-binding lysine of AONS is located at the end of a deep cleft that allows access of the pantothenate arm of pimeloyl-CoA . A cluster of positively charged residues at the entrance to this cleft forms a putative diphosphate binding site for CoA . The structure of E . coli AONS enables identification of the key residues of the PLP-binding site and thus provides a framework with which to understand the biochemical mechanism, which is similar to that catalysed by 5-aminolevulinate synthase and two other alpha-oxoamine synthases . Although AONS has a low overall sequence similarity with the catalytic domains of other alpha-oxoamine synthases, the structure reveals the regions of significant identity to be functionally important . This suggests that the organisation of the conserved catalytic residues in the active site is similar for all enzymes of this sub-class of PLP-dependent enzymes and they share a common mechanism . Knowledge of the three-dimensional structure of AONS will enable characterisation of the structural features of this enzyme sub-family that are responsible for this important type of reaction . Genes Dev, 1998 Nov 1, 12(21), 3431 - 41 Bacterial senescence: stasis results in increased and differential oxidation of cytoplasmic proteins leading to developmental induction of the heat shock regulon; Dukan S et al.; Aging, or senescence, is the progressive deterioration of every bodily function over time . A fundamental question that applies to all life forms, including growth-arrested bacteria, is why growing older by necessity causes organisms to grow more fragile . In this work, we demonstrate that the levels of oxidized proteins is correlated to the age of a stationary-phase Escherichia coli culture; both disulfide bridge formation of a cytoplasmic leader-less alkaline phosphatase and protein carbonyl levels increase during stasis . The stasis-induced increase in protein oxidation is enhanced in cells lacking the global regulators OxyR and sigmas . Some proteins were found to be specifically susceptible to stasis-induced oxidation; notably several TCA cycle enzymes, glutamine synthetase, glutamate synthase, pyruvate kinase, DnaK, and H-NS . Evidence that oxidation of target proteins during stasis serves as the signal for stationary-phase, developmental, induction of the heat shock regulon is presented by demonstrating that this induction is mitigated by overproducing the superoxide dismutase SodA . In addition, cells lacking cytoplasmic superoxide dismutase activity exhibit superinduction of heat shock proteins . The possibility that oxidative sensitivity of TCA cycle enzymes serves as a feedback mechanism down-regulating toxic respiration is discussed. Biochim Biophys Acta, 1998 Nov 8, 1442(2-3), 353 - 60 Molecular characterization of two novel transporters from human and mouse kidney and from LLC-PK1 cells reveals a novel conserved family that is homologous to bacterial and Aspergillus nucleobase transporters; Faaland CA et al.; Nucleobase transport is important for the metabolism of nucleic acids and antiviral and antineoplastic drugs . This transport has been functionally described in several mammalian cells but has not been well characterized molecularly . We report the cloning of two novel transporters . YSPL2 encodes a 650-residue protein and has an ubiquitous 8 kb transcript . The human and pig homologs are 95% similar . YSPL3 encodes a 598-residue protein with a 3 kb transcript that is expressed only in kidney and liver . Human YSPL2 and YSPL3 are 60% similar at the amino acid level and both show 31% similarity to the first nucleobase permease gene described in vertebrates, YSPL1 . These proteins appear to be members of a new family of possible nucleobase transporters with significant sequence similarities with bacterial and Aspergillus nucleobase transporters . Further functional studies will be needed to unveil the role of these transporters in nucleic acid metabolism in normal and in disease states. J Biol Chem, 1998 Nov 13, 273(46), 30110 - 5 Intersubunit interaction between transmembrane helices of the bacterial aspartate chemoreceptor homodimer; Umemura T et al.; The transmembrane domain that connects the extracellular and intracellular domains of cell-surface receptors must play a critical role in signal transduction . Here, we report studies of the interaction between the transmembrane helices (TM1 and TM2) of the Escherichia coli aspartate chemoreceptor (Tar) . Tar exists as a homodimer regardless of its state of ligand occupancy . A particular residue substitution in TM1 (A19K) abolishes the signaling ability of Tar . This signaling defect can be suppressed by single residue substitutions in TM2 (W192R, A198E, V201E, and V202L) . We have found that these suppressors can be divided into two groups . A198E and V201E (class 1) almost completely suppress the defects caused by A19K, and this suppression occurs between two subunits of the Tar dimer . In contrast, W192R and V202L (class 2) fail to suppress some signaling defects, and their suppression does not occur between subunits . Because disulfide-crosslinking studies predict that residues 198 and 201 point toward residue 19 of the partner subunit, we propose that the class 1 suppressors form an intersubunit salt bridge with Lys-19 . Indeed, A19K was suppressed by several additional aspartate or glutamate substitutions on the same face of TM2 occupied by residues 198 and 201 . None of these intersubunit salt bridges perturb signaling function, suggesting that the mechanism of transmembrane signal propagation does not involve large displacements (such as extensive rotation) of the TM1 and TM2 helices relative to each other. Science, 1998 Nov 6, 282(5391), 1133 - 5 Evidence that gene amplification underlies adaptive mutability of the bacterial lac operon; Andersson DI et al.; Adaptive mutability is the apparent alteration in specificity or rate of mutability seen in bacteria during stress . A model is proposed by which gene amplification during selective growth can give the appearance of adaptive mutability without requiring any change in mutability . The model is based on two assumptions, that a mutant lac locus with residual function allows growth if its copy number is increased, and that true reversion events are made more likely by replication of chromosomes with many copies of the locus . Apparent directed mutability, its recombination requirement, and its apparent independence of cell growth are all accounted for by the model . Evidence is provided for the required residual function and gene amplification. ASAIO J, 1998 Sep-Oct, 44(5), M587 - 91 Retention of limulus amoebocyte lysate reactive bacterial products by polysulfone dialyzers is affected by the type of disinfectant; Cappelli G et al.; To reduce the level of contamination by bacterial products, ultrafiltration systems have been introduced and validated for their capacity to block the passage of bacterial components reactive to the limulus amoebocyte lysate (LAL) test . In this study, the absorptive capacity of polysulfone membranes undergoing disinfection cycles with free chlorine and peracetic acid were evaluated at various concentrations and contact times . The results of this study implicate a relevant physicochemical derangement of the polysulfone membranes treated with sodium hypochlorite but not with peracetic acid, diluted peracetic acid (Dialox) or Amuchina . The implications for the practical use of ultrafilters are discussed. Brain Pathol, 1998 Oct, 8(4), 625 - 40 The bacterial endotoxin lipopolysaccharide has the ability to target the brain in upregulating its membrane CD14 receptor within specific cellular populations; Lacroix S et al.; Systemic injection of the bacterial endotoxin lipopolysaccharide (LPS) provides a very good mean for increasing the release of proinflammatory cytokines by circulating monocytes and tissue macrophages . There is now considerable evidence that LPS exerts its action on mononuclear phagocytes via the cell surface receptor CD14 . The aim of the present study was to verify the hypothesis that the brain has also the ability to express the gene encoding the LPS receptor, which may allow a direct action of the endotoxin onto specific cellular populations during blood sepsis . Adult male Sprague-Dawley rats were sacrificed 1, 3, 6 and 24 h after systemic (i.v . or i.p.) injection of LPS or the vehicle solution . Brains were cut from the olfactory bulb to the medulla in 30-microm coronal sections and mRNA encoding rat CD14 was assayed by in situ hybridization histochemistry using a specific 35S-labeled riboprobe . The results show low levels of CD14 mRNA in the leptomeninges, choroid plexus and along blood vessels of the brain microvasculature under basal conditions . Systemic injection of the bacterial endotoxin caused a profound increase in the expression of the gene encoding CD14 within these same structures as well as in the circumventricular organs (CVOs) the organum vasculosum of the lamina terminalis, subfornical organ, median eminence and area postrema . In most of these structures, the signal for CD14 mRNA was first detected at 1 h, reached a peak at 3 h post-injection, declined at 6 h, and return to basal levels 24 h after LPS treatment . Quite interestingly, a migratory-like pattern of CD14 positive cells was observed from all sensorial CVOs to deeper parenchymal brain 3 and 6 h after LPS injection . At 6 h post-challenge, small positive cells were found throughout the entire parenchymal brain and dual-labeling procedure indicated that different cells of myeloid origin have the ability to express CD14 in response to systemic LPS . These included CVO microglia, choroid plexus and leptomeninge macrophages, parenchymal and perivascular-associated microglial cells, although specific nonmyeloid cells were also positive for the LPS receptor . These results provide the very first evidence of a direct role of LPS on specific cell populations of the central nervous system, which is likely to be responsible for the transcription of proinflammatory cytokines; first within accessible structures from the blood and thereafter through scattered parenchymal cells during severe sepsis. J Clin Gastroenterol, 1998 Oct, 27(3), 269 - 70 Spontaneous bacterial peritonitis in a patient with gastric carcinoma; Makharia GK et al.; Spontaneous bacterial peritonitis (SBP) is classically described in patients with cirrhosis and nephrotic syndrome . However, SBP rarely occurs in patients with malignant ascites . We report a patient with gastric cancer with ascites, who developed SBP . Clinicians need to be aware of this complication in patients with malignant ascites. Microbiology, 1998 Oct, 144 ( Pt 10), 2759 - 69 Transmembrane topology of the two FhuB domains representing the hydrophobic components of bacterial ABC transporters involved in the uptake of siderophores, haem and vitamin B12; Groeger W et al.; Transport of siderophores of the hydroxamate type across the Escherichia coli cytoplasmic membrane depends on a periplasmic binding-protein-dependent (PBT) system . This uptake system consists of the binding protein FhuD, the membrane-associated putative ATP-hydrolase FhuC and the integral membrane protein FhuB . The two halves of FhuB {FhuB(N) and FhuB(C)}, both essential for transport, are similar with respect to structure and function . Regions were identified in FhuB(N) and FhuB(C) which are presumably involved in the interaction of the two FhuB halves with each other or with other components of the uptake system, or with the different substrates . To determine the topology of the membrane-embedded polypeptide chain, FhuB'-'beta-lactamase protein fusions were analysed . The experimental data suggest that each half of the FhuB is able to fold autonomously into the lipid bilayer, which is a prerequisite for the assembly of both halves into a transport-competent formation . The hydrophobic components from PBT systems involved in the uptake of siderophores, haem and vitamin B12 define a subclass of polytopic integral membrane proteins . The topology of these 'siderophore family' proteins differs from that of the equivalent components of other PBT systems in that each polypeptide (and each half of FhuB) consists of 10 membrane-spanning regions, with the N- and C-termini located in the cytoplasm . The conserved region at a distance of about 90 amino acids from the C-terminus, typical of all hydrophobic PBT proteins, is also oriented to the cytoplasm . However, in the 'siderophore family' proteins this putative ATPase interaction loop is followed by four instead of two transmembrane spans. Genomics, 1998 Nov 1, 53(3), 300 - 7 Cloning, expression, and mapping of ribonucleases H of human and mouse related to bacterial RNase HI; Cerritelli SM et al.; We identified two human sequences and one mouse sequence in the database of expressed sequence tags that are highly homologous to the N-terminal sequence of eukaryotic RNases H1 . The cDNAs for human RNASEH1 and mouse Rnaseh1 were obtained, their nucleotide sequences determined, and the proteins expressed in Escherichia coli and partially purified . Both proteins have RNase H activity in vitro and they bind to dsRNA and RNA-DNA hybrids through the N-terminal conserved motif present in eukaryotic RNases H1 . The RNASEH1 gene is expressed in all human tissues at similar levels, indicating that RNase H1 may be a housekeeping protein . The human RNASEH1 and mouse Rnaseh1 cDNAs were used to isolate BAC genomic clones that were used as probes for fluorescence in situ hybridization . The human gene was localized to chromosome 17p11.2 and the mouse gene to a nonsyntenic region on chromosome 12A3 . The chromosomal location and possible disease association of the human RNASEH1 gene are discussed . Protein Eng, 1998 Sep, 11(9), 825 - 32 Antibody affinity maturation using bacterial surface display; Daugherty PS et al.; A quantitative system for screening combinatorial single-chain Fv (scFv) antibody libraries was developed utilizing surface display on Escherichia coli and fluorescence-activated cell sorting (FACS) . This system was employed to isolate clones with high-affinity to a fluorescently-labeled hapten from libraries constructed by randomizing heavy and light-chain residues in the anti-digoxin 26-10 derived antibody, scFv(dig) . The use of flow cytometry enabled the detection of rare library members directly in heterogeneous populations and the optimization of selection conditions prior to sorting . A heavy-chain mutant having wild-type affinity (KD = 0.91+/-0.22 nM) and an expected representation frequency of less than 1 x 10(6), was selected to homogeneity after three rounds utilizing increasingly stringent selection conditions . The isolated clone possessed two distinct point mutations relative to the wild-type DNA sequence, yet still coded for the wild-type amino acid sequence, suggesting that the wild-type residues may be optimal at the randomized positions . An affinity improved clone (KD = 0.30+/-0.05 nM), having a dissociation constant approximately threefold lower than the wild-type antibody, was isolated from a smaller light-chain library in a single sorting step . Flow cytometry was shown to be a simple and rapid method for the determination of the relative hapten dissociation rate constants of selected clones without requiring subcloning . The relative rate constants estimated by FACS were confirmed by producing the scFv antibodies in soluble form and measuring hapten binding kinetics by surface plasmon resonance (SPR) . These results demonstrate that E.coli surface display, coupled with quantitative selection and analysis using FACS, has the potential to become a powerful tool for rapid isolation and characterization of desirable mutants from large polypeptide libraries. J Biol Regul Homeost Agents, 1998 Jul-Sep, 12(3), 53 - 62 Endogenous relatives of ADP-ribosylating bacterial toxins in mice and men: potential regulators of immune cell function; Haag F et al.; ADP-ribosylation of proteins, like phosphorylation, is a post-translational modification that can modulate protein function . Bacterial mono (ADP-ribosyl)transferases have been well studied, since potent and clinically important pathogenic exoenzymes such as diphtheria, cholera and pertussis toxins belong to this group . Some of these enzymes interfere with signal transduction mechanisms of host cells, and have become widely used as research tools in cell biology because of their high potency and selectivity . Recently, relatives of these toxins have been cloned from vertebrates . Seven members of a novel multigene family have been identified to date . Surprisingly, all are predicted to be extracellular proteins . Preferred tissues of expression are skeletal and cardiac muscle, testis and hematopoietic cells . ADP-ribosylation of target proteins on the cell surface of T cells and leukocytes have been found to modulate the transmission of extracellular signals to the cell interior. Hepatology, 1998 Nov, 28(5), 1187 - 90 Small intestine dysmotility and bacterial overgrowth in cirrhotic patients with spontaneous bacterial peritonitis; Chang CS et al.; Patients with bacterial overgrowth of the small intestine developed spontaneous bacterial peritonitis (SBP) more frequently than patients without bacterial overgrowth of the small intestine . The objective of this study was to determine whether the incidences of small intestine dysmotility and bacterial overgrowth are higher in cirrhotic patients with a history of SBP than in cirrhotic patients without SBP . Forty cirrhotic patients were enrolled in this study . There were 20 patients with a history of SBP and 20 patients without a history of SBP . Small intestine bacterial overgrowth was diagnosed by breath hydrogen test . Small intestine motility was recorded, by a 3-channel solid-state manometric catheter, for 24 hours . There were no statistical differences in age or sex between the two groups . The Child-Pugh scores in the SBP group were higher than in the non-SBP group (10.5 +/- 2.1 vs . 8.1 +/- 1.9, P < .01) . The incidence of bacterial overgrowth of the small intestine was higher in the SBP group than in the non-SBP group (70% vs . 20%, P < .01) . The amplitude and duration of migrating motor complex (MMC) activity fronts, as well as the number of clusters per hour, were similar in both groups . However, the frequency of MMC activity fronts was higher in the non-SBP group than in the SBP group (4.8 +/- 2.3/24 hours vs . 3.5 +/- 1.2/24 hours, P < .05) . In addition, the MMC velocity was significantly higher in the non-SBP group (8.3 +/- 2.6 vs . 5.3 +/- 2.1 cm/min, P < .01) . The incidence of bacterial overgrowth of the small intestine was higher in cirrhotic patients with history of SBP than in those without SBP . Small intestine motility dysfunction was more severe in cirrhotic patients with history of SBP . Impaired motility of the small intestine, causing bacterial overgrowth of the small intestine, may be one of the explanations for recurrent SBP in cirrhotic patients. J Gastroenterol Hepatol, 1998 Sep, 13 Suppl, S39 - 50 The role of gut-derived bacterial toxins and free radicals in alcohol-induced liver injury; Thurman RG et al.; Previous research from this laboratory using a continuous enteral ethanol (EtOH) administration model demonstrated that Kupffer cells are pivotal in the development of EtOH-induced liver injury . When Kupffer cells were destroyed using gadolinium chloride (GdCl3) or the gut was sterilized with polymyxin B and neomycin, early inflammation due to EtOH was blocked . Anti-tumour necrosis factor (TNF)-alpha antibody markedly decreased EtOH-induced liver injury and increased TNF-mRNA . These findings led to the hypothesis that EtOH-induced liver injury involves increases in circulating endotoxin leading to activation of Kupffer cells . Pimonidazole, a nitro-imidazole marker, was used to detect hypoxia in downstream pericentral regions of the lobule . Following one large dose of EtOH or chronic enteral EtOH for 1 month, pimonidazole binding was increased significantly in pericentral regions of the liver lobule, which was diminished with GdCl3 . Enteral EtOH increased free radical generation detected with electron spin resonance (ESR) . These radical species had coupling constants matching alpha-hydroxyethyl radical and were shown conclusively to arise from EtOH based on a doubling of the ESR lines when 13C-EtOH was given . Alpha-hydroxyethyl radical production was also blocked by the destruction of Kupffer cells with GdCl3 . It is known that females develop more severe EtOH-induced liver injury more rapidly and with less EtOH than males . Female rats on the enteral protocol exhibited more rapid injury and more widespread fatty changes over a larger portion of the liver lobule than males . Plasma endotoxin, ICAM-1, free radical adducts, infiltrating neutrophils and transcription factor NFkappaB were approximately two-fold greater in livers from females than males after 4 weeks of enteral EtOH treatment . Furthermore, oestrogen treatment increased the sensitivity of Kupffer cells to endotoxin . These data are consistent with the hypothesis that Kupffer cells participate in important gender differences in liver injury caused by ethanol. Biochem Biophys Res Commun, 1998 Oct 9, 251(1), 313 - 9 Bacterial lipopolysaccharide induces uncoupling protein-2 expression in hepatocytes by a tumor necrosis factor-alpha-dependent mechanism; Cortez-Pinto H et al.; The liver is a target for bacterial lipopolysaccharide (LPS) and participates in the metabolic response to endotoxemia . Recently published evidence indicates that LPS increases the expression of mitochondrial uncoupling protein-2 (UCP-2) mRNAs in several tissues, including the liver . Because hepatocytes in the healthy liver do not express UCP-2, LPS was thought to induce UCP-2 in liver macrophages, which express UCP-2 constitutively . However, the present studies of cultured peritoneal macrophages indicate that LPS reduces steady state levels of UCP-2 mRNAs in these cells . In contrast, UCP-2 mRNAs are induced in hepatocytes isolated from LPS treated rats and transfection of these hepatocytes with UCP-2 promoter-reporter constructs demonstrates substantial increases in UCP-2 promoter activity . LPS induction of hepatocyte UCP-2 expression is virtually abolished by prior treatment of rats with neutralizing antibodies to tumor necrosis factor alpha (TNF) . Futhermore, TNFalpha treatment induces UCP-2 mRNA accumulation in primary cultures of hepatocytes from healthy rats . Thus, hepatocytes are likely to be important contributors to endotoxin-related increases in liver UCP-2 via a mechanism that involves the LPS-inducible cytokine, TNFalpha . Nippon Geka Gakkai Zasshi, 1998 Aug, 99(8), 497 - 503 {Bacterial translocation in multiple organ failure}; Fukushima R et al.; Bacterial translocation has been defined as the passage of both viable and nonviable bacteria and their products (e.g., endotoxins) across the intestinal barrier to extraintestinal sites such as the mesenteric lymph nodes, liver, etc . It has been hypothesized that intestinally derived bacteria or endotoxins serve as triggers to initiate, perpetuate, or exacerbate the septic state and thereby promote the development of multiple organ failure (MOF) . In various animal studies, bacterial translocation has been associated with mortality and septic complications . Although most data on translocation have been derived from animal studies, convincing evidence has been provided that translocation may occur in humans during various disease states . The question still remains, however, of whether bacterial translocation is an important pathophysiological event in human disease or simply an epiphenomenon of severe disease, since the results are variable . Recent studies have indicated that the gut can produce important amounts of immunoinflammatory factors and that intestinal injury predisposes to distant organ injury even in the absence of detectable bacteria or endotoxins in the portal blood or tissues . This hypothesis may in part explain the inconsistent causal relationship between bacterial translocation and MOF. J Biol Chem, 1998 Oct 30, 273(44), 28799 - 804 Investigation of the secondary DNA-binding site of the bacterial recombinase RecA; Cazaux C et al.; The L2 loop is a DNA-binding site of RecA protein, a recombinase from Eschericha coli . Two DNA-binding sites have been functionally defined in this protein . To determine whether the L2 loop of RecA protein is part of the primary or secondary binding site, we have constructed proteins with site-specific mutations in the loop and investigated their biological, biochemical, and DNA binding properties . The mutation E207Q inhibits DNA repair and homologous recombination in vivo and prevents DNA strand exchange in vitro (Larminat, F., Cazaux, C., Germanier, M., and Defais, M . (1992) J . Bacteriol . 174, 6264-6269; Cazaux, C., Larminat, F., Villani, G., Johnson, N . P., Schnarr, M., and Defais, M . (1994) J . Biol . Chem . 269, 8246-8254) . We have found that mutant protein RecAE207Q lacked one of the two single stranded DNA-binding sites of wild type RecA . The remaining site was functional, and biochemical activities of the mutant protein were the same as wild type RecA with ssDNA in the primary binding site . The second mutation, E207K, reduced but did not eliminate DNA repair, SOS induction, and homologous recombination in vivo . In the presence of ATP, mutant protein RecAE207K catalyzed DNA strand exchange in vitro at a slower rate than wild type protein, and ssDNA binding at site I was competitively inhibited . These results show that the L2 loop is or is part of the functional secondary DNA-binding site of RecA protein. J Biol Chem, 1998 Oct 30, 273(44), 28785 - 90 Spectroscopic characterization of a novel multiheme c-type cytochrome widely implicated in bacterial electron transport; Roldan MD et al.; NapC is a member of a family of bacterial membrane-anchored tetra-heme c-type cytochromes that participate in a number of respiratory electron transport pathways . They are postulated to mediate electron transfer between membrane quinols/quinones and soluble periplasmic enzymes . The water-soluble heme domain of NapC has been expressed as a periplasmic protein . Mediated redox potentiometry and characterization by UV-visible, magnetic circular dichroism, and electron paramagnetic resonance spectroscopies demonstrates that soluble NapC contains four low spin hemes, each with bis-histidine axial ligation and with midpoint reduction potentials of -56, -181, -207, and -235 mV. Jpn J Thorac Cardiovasc Surg, 1998 Aug, 46(8), 667 - 70 Aneurysmal pouch on left coronary cusp accompanied by bacterial endocarditis; Nakayama M et al.; A 58-year-old male was admitted to our hospital with a preliminary diagnosis of bacterial endocarditis . After admission, echocardiography indicated the presence of vegetation-like tissues on both the left coronary cusp and the anterior mitral leaflet, although retrograde aortography two months earlier hadn't indicated an abnormal finding on the aortic cusp . The vegetation-like tissues had gradually enlarged despite the administration of antibiotics at another hospital, and aortic and mitral regurgitation had become severe . We decided to perform replacements of the aortic and mitral valves on the day of admission . During the operation, the aortic valve was found not to have vegetation, but an aneurysmal pouch on the left coronary cusp . It was supposed that either bacterial endocarditis or catheter injury had made a part of the aortic cusp weak and intolerant of diastolic pressure gradient, and as a result, the weakened part of the cusp progressively dilated into the left ventricle forming an aneurysmal pouch . To our knowledge, there have been only two previous reports of an aneurysmal pouch on the aortic cusp documented in the literature. Mikrobiologiia, 1998 Jul-Aug, 67(4), 437 - 51 {Bacterial genomes: nucleoid, chromosome, nucleotide map}; Prozorov AA; The structure of the genome of a bacterial cell was considered by invoking data derived by various methods, from light microscopy to sequencing of chromosomal DNA. Infect Immun, 1998 Nov, 66(11), 5286 - 94 Role of liver NK cells and peritoneal macrophages in gamma interferon and interleukin-10 production in experimental bacterial peritonitis in mice; Seki S et al.; Gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and interleukin-10 (IL-10) production by liver, spleen, lung, peripheral blood mononuclear cells (MNC), and peritoneal exudate cells (PEC) in experimental bacterial peritonitis was examined by cecum ligation and puncture (CLP) (with an 18-gauge needle) of BALB/c mice . MNC of organs were cultured for 18 h, and cytokine levels in supernatants were examined . Cytokines contained in peritoneal lavage fluid were regarded as those produced by PEC . Only liver MNC and PEC produced substantial amounts of IFN-gamma, and PEC were the main source of IL-10, especially 12 h after CLP . As reflected by the cytokine production by liver MNC and PEC, serum IFN-gamma and IL-10 levels were elevated after CLP . C57BL/6 (B6) mice and BALB/c nude mice showed a similar pattern of cytokine production . TNF-alpha levels in culture supernatants, peritoneal lavage fluid, and sera were not significantly elevated compared to those of sham-operated mice . In vivo depletion of NK cells of B6 mice with anti-asialo GM1 or anti-NK1.1 antibody greatly decreased IFN-gamma levels in liver MNC culture supernatants and sera, suggesting that liver NK cells are IFN-gamma producers . On the other hand, plastic-adherent PEC macrophages are the major IL-10 producers . Mice subjected to a cecum ligation and cut procedure (which have a more severe peritonitis) showed much higher IFN-gamma and IL-10 levels than those subjected to CLP, while mice subjected to CLP with a smaller (22-gauge) needle showed low levels of these cytokines . These findings show that liver NK cells and PEC macrophages are important for the production of proinflammatory and anti-inflammatory cytokines in bacterial peritonitis. Biochem Biophys Res Commun, 1998 Sep 29, 250(3), 798 - 804 Bacterial lipopolysaccharide increases interleukin-6 and prostaglandin release in rat cortical type I astrocytes by different mechanisms: role of anti-inflammatory agents; Grimaldi M et al.; LPS stimulated IL-6 release in a concentration-dependent manner from rat cortical type I astrocytes . This stimulatory action was completely abolished by Dexamethasone (DEX), but was not affected by indomethacin (IND), a 5-cyclooxigenase inhibitor . LPS-induced IL-6 release was partially inhibited by BW 4AC, a 5-lipoxygenase inhibitor . LPS concentration-dependently increased the release of PGE2 from type I astrocytes, an effect completely inhibited by IND . To rule out the possibility that DEX was inhibiting LPS-induced IL-6 release by blocking IL-6 gene expression, we tested the effect of DEX on interleukin 1beta(IL-1)-induced IL-6 release . DEX slightly inhibited IL-1-induced IL-6 release, while IL-1 releasing action on IL-6 was significantly reduced by IND . The involvement of nitric oxide (NO) generation on LPS-induced IL-6 release was also studied . We found that L-NO-arginine, an inhibitor of nitric oxide synthase, concentration-dependently reduced LPS-induced IL-6 release in astrocytes . In conclusion, we provide evidence that LPS action on IL-6 and PGE2 release can be ascribed to the activation of different transduction mechanisms, which can be pharmacologically dissected with the aid of anti-inflammatory drugs . Eur J Pediatr Surg, 1998 Aug, 8(4), 247 - 50 Bacterial translocation and T-lymphocyte populations in experimental short-bowel syndrome; Aldazabal P et al.; Bacterial translocation (BT) accounts in part for sepsis in short-bowel syndrome in which total parenteral nutrition (TPN) is routinely necessary . TPN "per se" facilitates BT and it has been suggested that decreased T-lymphocyte populations (TLP) in newborn rabbits and nude mice promote BT as well . We have tested the hypothesis that BT and modifications in TLP are to be expected in rats subjected to TPN and gut resection . Forty-five adult Wistar rats underwent central venous cannulations and were randomly assigned to one of three groups receiving for ten days three treatment regimes: - Group Sham (n = 17) oral intake of rat chow + saline (300 ml/kg/24 h) through a jugular vein catheter . - Group TPN (n = 17) fasting + infusion of all-in-one TPN solution (300 ml/kg/24 h) . - Group RES (n = 11) fasting, same TPN regime + 80% gut resection . At the end of the experiment they were sacrified and specimens (peripheral and portal blood, spleen and mesenteric lymph nodes) were recovered, cultured and/or assessed for CD4+ and CD8+ . Bacterial translocation was found in 47% of TPN animals, 92% of RES rats, but not in SHAM ones . Lymphocyte populations were not different in BT+ (n = 8) or BT- (n = 9) rats in the TPN group . TPN and resected animals showed a rise in CD4+ and a drop in CD8+ (then a better CD4+/CD8 ratio) when comparing with SHAM group rats . From this data we may conclude that: 1) BT is frequent if TPN is administered, and constant in resected animals . 2) No apparent relationship between the proportions of CD4+ and CD8+ lymphocytes and BT could be shown in TPN group . 3) High CD4+/CD8+ ratio in TPN and RES groups demonstrate that BT is possible even having good TLP. Commun Dis Public Health, 1998 Sep, 1(3), 206 - 7 An evaluation of Vitek--an automated system for bacterial identification and susceptibility testing; Downes A et al.; We evaluated the Vitek system for bacterial identification and susceptibility testing with reference to its speed, staffing requirements, user friendliness, and data management . Its performance was satisfactory in all these dimensions, but it is expensive. Microbiology, 1998 Sep, 144 ( Pt 9), 2599 - 606 Bacterial chemotactic motility is important for the initiation of wheat root colonization by Azospirillum brasilense; Vande Broek A et al.; Bacteria of the genus Azospirillum are able to colonize plant roots . Using the beta-glucuronidase (GUS) reporter system, various Azospirillum mutants, including mutants affected in chemotactic motility or extracellular polysaccharide biosynthesis, were investigated for their capacity to initiate wheat root colonization at the root hair zones . Only non-flagellated mutants and a generally non-chemotactic mutant exhibited a strongly reduced colonization ability as compared to the wild-type . No role of the Azospirillum calcofluor-binding polysaccharide in primary wheat root colonization could be observed . This is the first report demonstrating directly, by using different motility mutants, the requirement of bacterial motility in the establishment of the Azospirillum-plant root association. Invasion Metastasis, 1997, 17(4), 176 - 88 Effect of bacterial association on the phenotype and genotype of an Entamoeba histolytica clonal population; De Menezes LF et al.; A several-times-cloned population of Entamoeba histolytica trophozoites (clone MAVIII) was cultured under axenic (MAVIIIax), monoxenic (MAVIIImx) and polyxenic (MAVIIIpx) conditions . Clones MAVIIIax and MAVIIImx presented similar virulence in vitro, but differed in their virulence in vivo, whereas MAVIIIpx trophozoites were neither virulent in vitro or in vivo . The MAVIII clones maintained their zymodeme and exhibited three unusual glucose phosphate isomerase bands, absent in other E . histolytica strains studied . Similar patterns were shown by the three MAVIII clones in the signature of a 482-bp DNA fragment from the M17 gene (which encodes for a variable immunodominant antigen), obtained by low stringency single specific primer PCR technique . However, MAVIII clones displayed genotypic variability in the patterns obtained by the random amplified polymorphic DNA technique using total DNA as template . Results suggest that monomorphism is kept in certain regions of the genome, mainly in those carrying protein encoding genes, but a high polymorphism is present in total DNA of cloned trophozoites cultured under different conditions, confirming the plasticity of the E . histolytica genome. J Immunol, 1998 Oct 15, 161(8), 3930 - 5 Cyclosporin A enhances IL-12 production by CpG motifs in bacterial DNA and synthetic oligodeoxynucleotides; Redford TW et al.; Certain sequences of nucleotides (CpG motifs) in bacterial DNA or synthetic oligonucleotides (CpG DNA) promote the production of proinflammatory cytokines, including TNF-alpha, IFN-gamma, IL-6, and IL-12 . Here we demonstrate that the immunosuppressant cyclosporin A (CsA) unexpectedly enhanced CpG DNA-induced IL-12 production in murine splenocytes . CsA did not inhibit CpG DNA-induced TNF-alpha or IL-6 production, but decreased the production of IFN-gamma by CpG DNA . Upon examining mechanisms by which CsA increases IL-12 production, we found that CpG DNA can also induce IL-10 production in B cells and that this production was sensitive to CsA . IL-10 has anti-inflammatory effects and can reduce the production of IL-12 . To determine the possible role of CsA-modulated IL-10 production in mediating the increased IL-12 levels, splenocytes from IL-10 gene-disrupted mice (IL-10 -/-) and splenocytes cultured in anti-IL-10 Ab were studied . CpG DNA-stimulated IL-10 (-/-) splenocytes demonstrated no increase in IL-12 levels in the presence of CsA . Anti-IL-10 Ab treatment of normal splenocytes increased the magnitude of CpG DNA-induced IL-12 production to that seen with CsA . These results suggest that CpG DNA induces CsA-sensitive IL-10 production in B cells and that IL-10 acts as a negative feedback regulator of CpG DNA-induced IL-12 production. Int Dent J, 1998 Apr, 48(2), 104 - 10 Identification of bacterial markers by culture technique in evaluation of periodontal therapy; Dahlen G et al.; The aim of the present study was to evaluate whether the presence of A . actinomycetemcomitans, P . gingivalis and P . intermedia, as revealed by culture technique, could discriminate between three distinct adult patient groups, those: with recurrent periodontal disease, with cured periodontal disease or who were periodontally healthy . Forty one patients previously treated for advanced periodontitis were divided into recurrent or cured groups, with a third periodontally healthy reference group . All subjects were sampled for the three bacterial strains under scrutiny . Although all three micro-organisms were found significantly more often in diseased sites, it was concluded that a sample positive for all three may indicate a false record of disease activity . However, a sample negative for the three bacteria strongly indicates an absence of disease activity. J Matern Fetal Med, 1998 Sep-Oct, 7(5), 222 - 6 Bacteria-induced or bacterial product-induced preterm parturition in mice and rabbits is preceded by a significant fall in serum progesterone concentrations; Fidel PI Jr et al.; Bacterial products are thought to induce labor by stimulating the production of pro-inflammatory cytokines and prostaglandins in gestational tissues, leading to the onset of preterm parturition . Progesterone withdrawal is a prerequisite of parturition in many species . Yet a role for progesterone in the mechanisms responsible for preterm parturition, in the setting of infection, is unclear . The current studies were conducted to determine if a fall in serum progesterone concentrations occurs before the onset of bacterial product-induced preterm parturition in animals . Accordingly, pregnant mice at day 15 (70% gestation) were injected i.p . with Escherichia coli lipopolysaccharide (LPS; 50 microg/mouse) and timed-pregnant rabbits were inoculated transcervically with a suspension of E . coli to cause an ascending intrauterine infection . Control animals in both groups received equal volumes of sterile phosphate-buffered saline (PBS) solution . Blood specimens were collected at regular intervals and serum progesterone levels were determined by RIA . Within 14 h of LPS administration, mice delivered their pups . The median concentrations of serum progesterone were significantly lower at 1 h, 4 h, 10 h, and at the onset of preterm parturition (11-12 h) after LPS injection, compared to that in animals given PBS . Similarly, E . coli-inoculated rabbits delivered 1-2 days posttranscervical inoculation and demonstrated 60% decrease in serum progesterone within 12-24 h of inoculation compared to those given PBS . Parturition in both control groups occurred at term, following typical progesterone withdrawal . It is concluded that LPS administration to pregnant mice and ascending intrauterine infection in pregnant rabbits is associated with a dramatic fall in serum progesterone concentrations prior to the onset of parturition. Hosp Med, 1998 Jun, 59(6), 447 - 50 Bacterial vaginosis: its importance in obstetrics; Woodrow N et al.; Bacterial vaginosis is associated with adverse sequelae, including late miscarriage, preterm prelabour rupture of the membranes, chorioamnionitis, postpartum endometritis and preterm labour and delivery . It is easy to diagnose and treat; intervention reduces the incidence of adverse sequelae . Symptomatic women and those who are at increased risk of infectious morbidity should be screened. J Biol Chem, 1998 Oct 23, 273(43), 28142 - 8 Roles of residues in mammalian mitochondrial elongation factor Ts in the interaction with mitochondrial and bacterial elongation factor Tu; Zhang Y et al.; The crystal structure of the complex between Escherichia coli elongation factors Tu and Ts (EF-Tu.Ts) and subsequent mutagenesis work have provided insights into the roles of a number of residues in E . coli EF-Ts in its interaction with EF-Tu . The corresponding residues in bovine mitochondrial EF-Ts (EF-Tsmt) have been mutated . The abilities of the resulting EF-Tsmt derivatives to stimulate the activities of both E . coli and mitochondrial EF-Tu have been tested . Mutation of several residues in EF-Tsmt corresponding to amino acids important for the activity of E . coli EF-Ts has little or no effect on the activity of the mitochondrial factor, suggesting that these factors may use somewhat different mechanisms to promote guanine nucleotide exchange . In general, mutations that reduce the strength of the interaction between EF-Tsmt and E . coli EF-Tu increase the ability of EF-Tsmt to stimulate the activity of the bacterial factor . In contrast, these mutations tend to reduce the ability of EF-Tsmt to stimulate the activity of EF-Tumt . For example, F19A/I20A and H176A derivatives of EF-Tsmt are as active as E . coli EF-Ts in simulating E . coli EF-Tu . However, these mutations significantly decrease the ability of EF-Tsmt to stimulate EF-Tumt. Biochemistry, 1998 Oct 13, 37(41), 14457 - 62 Proton uptake by carboxylic acid groups upon photoreduction of the secondary quinone (QB) in bacterial reaction centers from Rhodobacter sphaeroides: FTIR studies on the effects of replacing Glu H173; Nabedryk E et al.; In the photosynthetic reaction center (RC) from Rhodobacter sphaeroides, Glu H173, located approximately 7 A from the center of the secondary quinone acceptor QB, is expected to contribute to proton uptake upon QB- formation in response to the movement of an electron in its vicinity . Steady-state FTIR difference spectroscopy provides a method to monitor proton uptake by carboxylic acids upon photochemical changes . The FTIR spectra corresponding to the photoreduction of QB were obtained at pH 7 for RCs containing Glu (native), Gln (EQ H173), or Asp (ED H173) at the H173 site . No new bands were observed in the carboxylic acid region (1770-1700 cm-1) in any of the mutant RCs compared to native RCs . In addition, the positive band at 1728 cm-1, previously assigned to Glu L212 {Nabedryk, E., Breton, J., Hienerwadel, R., Fogel, C., Mantele, W., Paddock, M . L., and Okamura, M . Y . (1995) Biochemistry 34, 14722-14732}, remained present in all of the mutant RCs . This result shows that Glu H173 is not a major contributor to proton uptake upon QB- formation and further strengthens the assignment of the 1728 cm-1 band to Glu L212 . An increase in the 1728 cm-1 band was observed in the EQ H173 RCs compared to that of either the ED H173 or native RCs . These changes are consistent with Glu and Asp at H173 remaining ionized in the QB and QB- states . Changes in the absorption regions of the semiquinone and amide or side chain groups in the spectra of the mutant RCs suggest slight changes in the protein structure compared to those of native RCs, which could contribute to the altered kinetics observed in the mutant RCs. Proc Natl Acad Sci U S A, 1998 Oct 13, 95(21), 12306 - 11 Low frequency vibrational modes in proteins: changes induced by point-mutations in the protein-cofactor matrix of bacterial reaction centers; Rischel C et al.; As a step toward understanding their functional role, the low frequency vibrational motions (<300 cm-1) that are coupled to optical excitation of the primary donor bacteriochlorophyll cofactors in the reaction center from Rhodobacter sphaeroides were investigated . The pattern of hydrogen-bonding interaction between these bacteriochlorophylls and the surrounding protein was altered in several ways by mutation of single amino acids . The spectrum of low frequency vibrational modes identified by femtosecond coherence spectroscopy varied strongly between the different reaction center complexes, including between different mutants where the pattern of hydrogen bonds was the same . It is argued that these variations are primarily due to changes in the nature of the individual modes, rather than to changes in the charge distribution in the electronic states involved in the optical excitation . Pronounced effects of point mutations on the low frequency vibrational modes active in a protein-cofactor system have not been reported previously . The changes in frequency observed indicate a strong involvement of the protein in these nuclear motions and demonstrate that the protein matrix can increase or decrease the fluctuations of the cofactor along specific directions. Acta Microbiol Immunol Hung, 1998, 45(2), 257 - 61 Effect of antilymphocyte serum on bacterial translocation in mice; Anderlik P et al.; Following intraperitoneally applied treatment with antilymphocyte serum (ALS) of immunosuppressive effect no bacterial translocation (BT) was observed in mice . The ALS treatment applied in combination with other immunosuppressive agents such as lymphotropic cytostatics as dianhydrogalactitol or chlorpromazine did not increase the mice's drug sensitivity to the used agents . According to our results, ALS can be suitable for combined application with other immunosuppressive agents as it can increase immunosuppression without side-effects such as those induced by bacterial translocation. Immunology, 1998 Jul, 94(3), 285 - 9 Immuno-stimulatory effects of bacterial-derived plasmids depend on the nature of the antigen in intramuscular DNA inoculations; Lee SW et al.; The CpG motifs of bacterial-derived plasmids augment antigen-specific immune responses and steer those responses towards the T helper 1 (Th1) type . In this study, we have addressed the immuno-stimulatory effect of intramuscular co-administration of CpG motifs containing vector DNA on the modulation of immune responses to the haemagglutinin (HA) and the nucleoprotein (NP) proteins of influenza virus . The co-administration of vector DNA with a HA-encoding plasmid DNA showed a significant enhancement in the total IgG response, the generation of cytotoxic T lymphocyte (CTL), and the T-cell proliferative response . In the case of NP-encoding plasmid DNA inoculations, the co-administration of vector DNA slightly decreased the total IgG response, although the IgG2a/IgG1 ratio and the CTL responses to NP were significantly increased . These observations suggest that the immuno-stimulatory effects of bacterial-derived plasmids depend upon the nature of the co-administered antigen. Am J Med Sci, 1998 Oct, 316(4), 257 - 63 The pathogenesis of HLA-B27 arthritis: role of HLA-B27 in bacterial defense; Ikeda M et al.; The way in which a host accommodates invasive facultative intracellular bacteria must be the key to the development of reactive arthritis . Investigators have analyzed the bacterial events at several levels: invasion into host cells, intracellular survival, translocation from the sites of infection to the joints, residence in the joints, and evasion of host defense . Because HLA-B27 is present in higher incidence in patients with reactive arthritis and is an essential gene in the related ankylosing spondylitis, the role of HLA-B27 in host defense is also assumed to be important in the development of reactive arthritis . This review summarizes the various studies in this field. J Bacteriol, 1998 Oct, 180(20), 5375 - 83 Escherichia coli promoters with UP elements of different strengths: modular structure of bacterial promoters; Ross W et al.; The alpha subunit of Escherichia coli RNA polymerase (RNAP) participates in promoter recognition through specific interactions with UP element DNA, a region upstream of the recognition hexamers for the sigma subunit (the -10 and -35 hexamers) . UP elements have been described in only a small number of promoters, including the rRNA promoter rrnB P1, where the sequence has a very large (30- to 70-fold) effect on promoter activity . Here, we analyzed the effects of upstream sequences from several additional E . coli promoters (rrnD P1, rrnB P2, lambda pR, lac, merT, and RNA II) . The relative effects of different upstream sequences were compared in the context of their own core promoters or as hybrids to the lac core promoter . Different upstream sequences had different effects, increasing transcription from 1.5- to approximately 90-fold, and several had the properties of UP elements: they increased transcription in vitro in the absence of accessory protein factors, and transcription stimulation required the C-terminal domain of the RNAP alpha subunit . The effects of the upstream sequences correlated generally with their degree of similarity to an UP element consensus sequence derived previously . Protection of upstream sequences by RNAP in footprinting experiments occurred in all cases and was thus not a reliable indicator of UP element strength . These data support a modular view of bacterial promoters in which activity reflects the composite effects of RNAP interactions with appropriately spaced recognition elements (-10, -35, and UP elements), each of which contributes to activity depending on its similarity to the consensus. Appl Microbiol Biotechnol, 1998 Aug, 50(2), 181 - 6 Bacterial complementation as a means to test enzyme-ligand interactions; Canyuk B et al.; A bacterial complementation assay has been developed for the rapid screening of a large number of compounds to identify those that inhibit an enzyme target for structure-based inhibitor design . The target enzyme is the hypoxanthine phosphoribosyltransferase (HPRT) . This enzyme has been proposed as a potential target for inhibitors that may be developed into drugs for the treatment of diseases caused by several parasites . The screening assay utilizes genetically deficient bacteria complemented by active, recombinant enzyme grown in selective medium in microtiter plates . By comparing absorbance measurements of bacteria grown in the presence and absence of test compounds, the effect of the compounds on bacterial growth can be rapidly assayed . IC50 values for inhibition of bacterial growth are a reflection of the ability of the compounds to bind and/or inhibit the recombinant enzyme . We have tested this bacterial complementation screening assay using recombinant HPRT from the parasites . Plasmodium falciparum and Trypanosoma cruzi, as well as the human enzyme . The results of these studies demonstrate that a screening assay using bacterial complement selection can be used to identify compounds that target enzymes and can become an important part of structure-based drug design efforts. AIDS, 1998 Sep 10, 12(13), 1699 - 706 Bacterial vaginosis and disturbances of vaginal flora: association with increased acquisition of HIV; Taha TE et al.; BACKGROUND: Cross-sectional studies suggest an association between bacterial vaginosis (BV) and HIV-1 infection . However, an assessment of a temporal effect was not possible . OBJECTIVES: To determine the association of BV and other disturbances of vaginal flora with HIV seroconversion among pregnant and postnatal women in Malawi, Africa . DESIGN: Longitudinal follow-up of pregnant and postpartum women . METHODS: Women attending their first antenatal care visit were screened for HIV after counselling and obtaining informed consent . HIV-seronegative women were enrolled and followed during pregnancy and after delivery . These women were again tested for HIV at delivery and at 6-monthly visits postnatally . Clinical examinations and collection of laboratory specimens (for BV and sexually transmitted diseases) were conducted at screening and at the postnatal 6-monthly visits . The diagnosis of BV was based on clinical criteria . Associations of BV and other risk factors with HIV seroconversion, were examined using contingency tables and multiple logistic regression analyses on antenatal data, and Kaplan-Meier proportional hazards analyses on postnatal data . RESULTS: Among 1196 HIV-seronegative women who were followed antenatally for a median of 3.4 months, 27 women seroconverted by time of delivery . Postnatally, 97 seroconversions occurred among 1169 seronegative women who were followed for a median of 2.5 years . Bacterial vaginosis was significantly associated with antenatal HIV seroconversion (adjusted odds ratio = 3.7) and postnatal HIV seroconversion (adjusted rate ratio = 2.3) . There was a significant trend of increased risk of HIV seroconversion with increasing severity of vaginal disturbance among both antenatal and postnatal women . The approximate attributable risk of BV alone was 23% for antenatal HIV seroconversions and 14% for postnatal seroconversions . CONCLUSIONS: This prospective study suggests that progressively greater disturbances of vaginal flora, increase HIV acquisition during pregnancy and postnatally . The screening and treating of women with BV could restore normal flora and reduce their susceptibility to HIV. Gut, 1998 Jul, 43 Suppl 1, S2 - 5 Bacterial factors and immune pathogenesis in Helicobacter pylori infection; Shimoyama T et al.; Virulent Helicobacter pylori strains which have been clinically associated with severe outcome induce increased gastric mucosal immune responses . Although several bacterial pathogenic factors have been shown to have a considerable role in H pylori infection, variability in host immune responses may also contribute to mucosal damage in H pylori associated gastritis. Appl Environ Microbiol, 1998 Oct, 64(10), 3690 - 7 Ellipsometric measurement of bacterial films at metal-electrolyte interfaces Busalmen JP, de Sanchez SR, Schiffrin DJ. Ellipsometric measurements were used to monitor the formation of a bacterial cell film on polarized metal surfaces (Al-brass and Ti) . Under cathodic polarization bacterial attachment was measured from changes in the ellipsometric angles . These were fitted to an effective medium model for a nonabsorbing bacterial film with an effective refractive index (nf) of 1.38 and a thickness (df) of 160 +/- 10 nm . From the optical measurements a surface coverage of 17% was estimated, in agreement with direct microscopic observations . The influence of bacteria on the formation of oxide films was monitored by ellipsometry following the film growth in situ . A strong inhibition of metal oxide film formation was observed, which was assigned to the decrease in oxygen concentration due to the presence of bacteria . It is shown that the irreversible adhesion of bacteria to the surface can be monitored ellipsometrically . Electrophoretic mobility is proposed as one of the factors determining bacterial attachment . The high sensitivity of ellipsometry and its usefulness for the determination of growth of interfacial bacterial films is demonstrated. J Immunol Methods, 1998 Jul 1, 216(1-2), 165 - 81 Antibody engineering: comparison of bacterial, yeast, insect and mammalian expression systems; Verma R et al.; Engineered antibody molecules, and their fragments, are being increasingly exploited as scientific and clinical tools . However, one factor that can limit the applicability of this technology is the ability to express large amounts of active protein . In this review we describe the relative advantages and disadvantages of bacterial, yeast, insect and mammalian expression systems, and discuss some of the problems that can be encountered when using them . There is no 'universal' expression system, that can guarantee high yields of recombinant product, as every antibody-based molecule will pose its own problems in terms of expression . As a result the choice of system will depend on many factors, including the molecular species being expressed, the precise sequence of the individual antibody and the preferences of the individual investigator . However, there are general rules with regards to the design of expression vectors and systems which will help the investigator to make informed choices as to which strategy might be appropriate for their application. Appl Environ Microbiol, 1998 Oct, 64(10), 3927 - 31 Bacterial stress responses to 1-megahertz pulsed ultrasound in the presence of microbubbles; Vollmer AC et al.; Members of a panel of stress-responsive biosensors have been used to study the effect of megahertz frequency ultrasound on Escherichia coli . Insonification causes acoustic cavitation, the collapse of oscillating microbubbles in solution, which can damage bacterial cells . A focused 1-MHz ultrasound transducer, capable of generating a spatial peak pulse average intensity of 500 W/cm2, was used to treat liquid bacterial cultures . Stress-responsive promoters fused to luxCDABE allowed the continuous measurement of light produced as a result of protein damage, DNA damage, oxidative stress, and membrane perturbation . A promoter responsive to ammonia limitation was not transcriptionally activated under test conditions . In contrast to bacteria in exponentially growing cultures, those in stationary-phase cultures were more resistant to the effects of ultrasound treatment . Quantification of the degree of acoustic cavitation due to symmetric bubble collapse was measured by a 20-MHz passive transducer, the output of which appears to be only partially correlated with cellular damage and survival . The methods and results summarized here provide the basis for further investigation into applications, including the purification of water samples. Otolaryngol Pol, 1997, 51 Suppl 25, 188 - 92 {Analysis of bacterial flora of the larynx: analysis of material collected in 1994-1996}; Wilczynski K et al.; This study reveals conclusions which source is analysis of 621 people with the pharyngs diseases from 1994 to 1996. Biochim Biophys Acta, 1998 Jul 20, 1365(3), 404 - 420 Triplet energy transfer in bacterial photosynthetic reaction centres; Angerhofer A et al.; {3-vinyl}-132-OH-bacteriochlorophyll a has been selectively exchanged against native bacteriochlorophyll a in the monomer binding sites at the A- and B-branch of the photosynthetic reaction centre from Rhodobacter sphaeroides . Transient absorption difference measurements were performed on these samples over a temperature range from 4.2 to 300 K with 20 ns time resolution . Specifically the decay of the primary donor triplet state, 3P870, as well as the rise and decay rates of the carotenoid triplet state, 3Car (spheroidene), were measured . The observed rates revealed a thermally activated carotenoid triplet formation corresponding to the decay of the primary donor triplet state . The activation energies for the triplet energy transfer process were 100(+/-10) cm-1 for reaction centers from wild-type Rhodobacter sphaeroides 2.4.1, with and without exchange of the monomeric bacteriochlorophyll on the electron transfer-active branch, BA . For reaction centers from Rhodobacter sphaeroides R26.1 with both monomers exchanged against {3-vinyl}-132-OH-bacteriochlorophyll a, and subsequent spheroidene reconstitution the activation energy was 460(+/-20) cm-1 . These activation energies correspond to the energy difference between the triplet states of the accessory BChl monomer, BB, and the primary donor when native BChl a or {3-vinyl}-132-OH-BChl a is present in the BB binding site . In all samples the 3Car formation rates were bi-phasic over a large temperature range . A fast temperature-independent rate was observed on the wavelength of the carotenoid triplet-triplet absorption which dominated at very low temperatures . Additionally, a slower temperature-independent 3Car formation rate was observed at low temperatures which could be explained with the assumption of heterogeneity in the energy barrier (3BB) and/or the primary donor triplet state (3P870) . A tunneling mechanism as proposed earlier by Kolaczkowski (PhD thesis, Brown University, 1989) is not only unnecessary but also incompatible with the available experimental data. Ecotoxicol Environ Saf, 1998 Oct, 41(2), 189 - 94 Modulation of drug-metabolizing systems by bacterial endotoxin in carp liver and immune organs; Marionnet D et al.; This report describes a study of the effects of bacterial endotoxin {lipopolysaccharide (LPS)} on cytochrome P450 levels and ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST) activities in liver and two main immune organs of carp: spleen and head kidney . Also studied was the paucity of the carp drug-metabolizing system in an environment subject to pollution by a polycyclic aromatic hydrocarbon, 3-methylcholanthrene (3MC), when fish respond to an immune activation by lipopolysaccharide (LPS) . In the presence of bacterial endotoxin the basal cytochrome P450 levels were decreased in liver and spleen . EROD activity was increased in liver and basal GST activity was increased in spleen . When fish were treated concomitantly with 3MC and LPS, a suppression of cytochrome P450 induction in liver and head kidney was observed . EROD activity induced by 3MC was not modified by administration of LPS . GST activity was suppressed by treatment with LPS and inducing agent in liver and head kidney . In the present study it was found that endotoxin can have profound and differential effects on fish basal biotransformation of drugs in the liver and immune organs . Also, the induction of biotransformation enzymes by 3MC was modified when fish responded to an immune stimulation . Indian J Exp Biol, 1998 Mar, 36(3), 315 - 7 Effect of rhinax on bacterial lipopolysaccharide induced endotoxemia in rats; Dhuley JN et al.; Administration of lipopolysaccharide (LPS) at 3 mg/kg, i.p . in rats resulted in reduced food intake, febrile hyperthermia, decreased body weight and reduced muscle performance in treadmill tests . It also induced some biochemical changes like increased serum levels of transaminases, acid phosphatase, pseudocholinesterase, free fatty acids and decreased blood glucose and liver glycogen levels . Rhinax (RHX), a herbal formulation, at 160 mg/kg, p.o . improved muscle performance but had no effect on the elevated temperature or the reduced body weight of rats weakened by LPS . It also normalised various biochemical alterations induced by LPS . The results of these studies indicate efficacy of RHX as an antifatigue agent to improve muscular performance. Arch Mal Coeur Vaiss, 1998 Jul, 91(7), 899 - 902 {Mycotic aneurysm in acute bacterial mitral valve endocarditis . Apropos of a case}; Remadi JP et al.; A 24 year old man presented with acute endocarditis of the mitral valve . Rupture of a mycotic cerebral aneurysm on the 20th day was successfully treated by interventional catheterisation . Several days later, he underwent mitral valvuloplasty under good conditions . The postoperative period was uncomplicated but emergency surgery was required for a mycotic aneurysm of the superior mesenteric artery . The patient was discharged from hospital without severe neurological sequellae and with a continent mitral valve. Biochim Biophys Acta, 1998 Oct 1, 1400(1-3), 19 - 27 Bacterial and archeal type I topoisomerases; Tse-Dinh YC; Bacterial and archeal type I topoisomerases, including topoisomerase I, topoisomerase III and reverse gyrase, have different potential roles in the control of DNA topology including regulation of supercoiling and maintenance of genetic stability . Analysis of their coding sequences in different organisms shows that they belong to the type IA family of DNA topoisomerases, but there is variability in organization of various enzymatic domains necessary for topoisomerase activity . The torus-like structure of the conserved transesterification domain with the active site tyrosine for DNA cleavage/rejoining suggests steps of enzyme conformational change driven by DNA substrate and Mg(II) cofactor binding, that are required for catalysis of change in DNA linking number. Biochemistry, 1998 Sep 22, 37(38), 13165 - 73 Activation of distinct transcription factors in neutrophils by bacterial LPS, interferon-gamma, and GM-CSF and the necessity to overcome the action of endogenous proteases; McDonald PP et al.; Human neutrophils can be induced to actively transcribe a number of early-response genes, in particular those encoding cytokines, chemokines, and the high-affinity surface receptor for IgG, FcgammaRI . Although little is known to date about the regulation of gene transcription in neutrophils, several indications point to a role for distinct transcription factors, such as members of the NF-kappaB and STAT families . In this study, we investigated whether these transcription factors become activated under stimulatory conditions which are known to induce gene transcription in neutrophils . Unexpectedly, we found that conventional procedures employed to prepare cellular extracts cause the release of proteolytic activities that are normally stored in intracellular granules, resulting in the degradation of various NF-kappaB/Rel and STAT proteins . To circumvent this problem, we developed an alternative procedure which allowed us to show that in neutrophils, LPS and TNFalpha induce a NF-kappaB DNA-binding activity which essentially consists of p50/RelA dimers, and that IFNgamma promotes the binding of STAT1 homodimers to the IFNgamma response region of the FcgammaRI promoter . Moreover, we report that neutrophil stimulation with GM-CSF results in the formation of a STAT5-containing DNA-binding activity . Collectively, the current findings open new perspectives about mechanisms that are likely to regulate gene transcription in neutrophils . In addition, the procedure described herein could prove useful in other cell types that express high levels of endogenous proteases. Chemosphere, 1998 Jun, 36(15), 3167 - 80 Toxicological evaluation of constructed wetland habitat sediments utilizing Hyalella azteca 10-day sediment toxicity test and bacterial bioluminescence; Steevens JA et al.; A toxicological evaluation was conducted on wetland habitats created as a result of run-off from agricultural areas . These temporary wetlands were created by using drop pipes as a means of reducing erosional cutting in agricultural fields . Toxicity bioassays utilizing bacterial bioluminescence and Hyalella azteca were used to assess sediment pore water and whole sediment, respectively . Inhibition of bacterial bioluminescence was initially used to determine relative toxicities of pore water from ten wetland sites . Constructed wetland sites were compared to the University of Mississippi Biological Field Station, a relatively pristine reference site . The H . azteca ten day sediment toxicity test was utilized to assess sediment from four selected sites using survival and growth as toxicological endpoints . Results from the toxicological evaluation, along with extensive ecological evaluations, were used to assess the best approach for implementation of temporary wetland habitats with existing agricultural practices. Brain Res Bull, 1998 Aug, 46(6), 541 - 6 Nitric oxide and prostaglandin E2 formation parallels blood-brain barrier disruption in an experimental rat model of bacterial meningitis; Jaworowicz DJ Jr et al.; During meningitis, the host produces a plethora of signaling agents as part of a coordinated defense mechanism against invading pathogens . Nitric oxide (NO) and prostaglandin E2 (PGE2) are two such inflammatory mediators produced in response to bacterial endotoxins . Disruption of the blood-brain barrier (BBB) is one of many pathophysiological consequences of meningitis . The present objective was to examine the time-course of NO and PGE2 production in relationship to BBB permeability alterations during experimentally-induced meningitis . Meningeal inflammation was elicited by intracisternal administration of the bacterial endotoxin, lipopolysaccharides (LPS; 200 microg), and NO, PGE2, and BBB integrity were monitored over the next 24 h . Meningeal NO production was assessed by headspace chemiluminescence; cerebrospinal fluid PGE2 was determined by enzyme-linked immunosorbent assay (ELISA) immunoassay; and BBB integrity was determined by the brain accumulation of 14C-sucrose . Similar time-course profiles for NO and PGE2 were observed, with a peak effect for both inflammatory mediators observed within 6-8 h after intracisternal LPS dosing . Statistically significant (p < 0.05) disruption of the BBB was observed in various brain regions . Strikingly similar temporal relationships were observed for NO and PGE2 production and BBB disruption . These results suggest the hypothesis that NO and PGE2 may act in conjunction to disrupt the BBB during experimental meningitis. Biol Neonate, 1998 Nov, 74(5), 372 - 5 The fetal glycoprotein, fetuin, counteracts ill-effects of the bacterial endotoxin, lipopolysaccharide, in pregnancy; Dziegielewska KM et al.; We show that fetuin, a fetal glycoprotein present in fetal plasma in concentrations substantially higher than in the adult, can exert a protective function against ill-effects of the bacterial endotoxin, lipopolysaccharide (LPS), in pregnancy . The concentration of fetuin in plasma of pregnant rats (E17 gestation) was artificially increased by repeated intraperitoneal administration of this protein . This was followed by an injection of a standard dose of LPS, a dose that produced in control animals (no additional fetuin) nearly 50% abortions and 40% maternal deaths . None of the females exposed to increased fetuin died following LPS injection . Nine out of 10 multigravida animals carried their pregnancy to full term but all primagravidas aborted. FEBS Lett, 1998 Sep 4, 434(3), 387 - 93 Characterization of early induced genes in Arabidopsis thaliana responding to bacterial inoculation: identification of centrin and of a novel protein with two regions related to kinase domains; Cordeiro MC et al.; The early response to bacterial inoculation has been investigated and two Arabidopsis genes, ap3.3a and ap4.3a have been characterized . The AP3.3A protein showed high identity to centrin, a ubiquitous cytoskeletal protein first identified in unicellular green alga . Amino-acid sequence analyses of the AP4.3A protein indicates that the second gene characterized encodes an unusual protein with two putative kinase domains . Expression of ap3.3a and ap4.3a was rapidly induced after pathogen inoculation . A role of ap3.3a in plant defense could be postulated based on its preferential induction during the incompatible interactions analyzed . In contrast, activation of ap4.3a was not specific and could be related to a more general stress response. Ugeskr Laeger, 1998 Aug 17, 160(34), 4855 - 9 {Diagnostic value of C-reactive protein in bacterial infections . Review of the literature}; Dahler-Eriksen BS et al.; Conflicting data for predictive values for C-reactive protein (CRP) in its ability to distinguish between viral and bacterial diseases are reviewed . Study designs regarding setting, patient-mix, severity of disease and prevalence seem to determine the magnitude of predictive values . We have calculated predictive values for patients suspected of septicaemia, meningitis, appendicitis, cholecystitis, upper- and lower respiratory disease, acute sinusitis and acute otitis media, and revealed the highest predictive values among patients suspected for severe and generalized infections . More localized diseases have lower predictive values . We emphasize the importance of a study design where the circumstances resemble the real situations in which the test is supposed to be used . This will ensure the clinical applicability of predictive values for a diagnostic test. Genomics, 1998 Aug 15, 52(1), 9 - 16 Mapping an endometrial cancer tumor suppressor gene at 10q25 and development of a bacterial clone contig for the consensus deletion interval; Peiffer-Schneider S et al.; Frequent loss of chromosome 10q sequences in endometrial cancers suggests the involvement of a tumor suppressor gene . Previous loss-of-heterozygosity (LOH)studies have pointed to the 10q25-q26 region as the likely site of a tumor suppressor involved in endometrial tumorigenesis (S . L . Peiffer et al., 1995, Cancer Res . 55: 1922-1926; S . Nagase et al., 1996, Br . J . Cancer 74: 1979-1983; S . Nagase et al.,1997, Cancer Res . 57: 1630-1633) . In an attempt to define further the localization of a tumor suppressor gene at 10q25, we screened a panel of 123 endometrioid adenocarcinomas for loss of heterozygosity of 10q25.3 sequences . Forty-three (35%) revealed LOH at one or more loci . The observed patterns of allelic loss define a minimum consensus region of deletion between D10S221 and D10S610 . A sequence-ready bacterial clone contig and a long-range restriction map for a 1-Mb interval spanning the deletion region were developed as the first step in experiments directed toward the discovery the 10q25 tumor suppressor . Genomics, 1998 Aug 15, 52(1), 1 - 8 An improved approach for construction of bacterial artificial chromosome libraries; Osoegawa K et al.; Presented here are improved methodologies that enable the generation of highly redundant bacterial artificial chromosome/P1-derived artificial chromosome libraries, with larger and relatively uniform insert sizes . Improvements in vector preparation and enhanced ligation conditions reduce the number of background nonrecombinant clones . Preelectrophoresis of immobilized high-molecular-weight DNA removes inhibitors of the cloning process, while sizing DNA fragments twice within a single gel effectively eliminates small restriction fragments, thus increasing the average insert size of the clones . The size-fractionated DNA fragments are recovered by electroelution rather than the more common melting of gel slices with subsequent beta-agarase treatment . Concentration of the ligation products yields a 6- to 12-fold reduction in the number of electroporations required in preparing a library of desirable size . These improved methods have been applied to prepare PAC and BAC libraries from the human, murine, rat, canine, and baboon genomes with average insert sizes ranging between 160 and 235 kb . Acta Obstet Gynecol Scand, 1998 Aug, 77(7), 701 - 6 IL-1beta, IL-6, TNFalpha, fetal fibronectin, and endotoxin in the lower genital tract of pregnant women with bacterial vaginosis; Mattsby-Baltzer I et al.; BACKGROUND: In our studies on women with bacterial vaginosis (BV) in early pregnancy a strong association has been found between BV and the levels of endotoxin or interleukin-1alpha (IL-1alpha) in the lower genital tract . In the present study we investigated if an association could be found between BV and other cytokines (IL-1beta, IL-6, tumor necrosis factor alpha, TNF) or fetal fibronectin (FFN) . The cytokine-inducing capacity of endotoxins present in the cervical mucus was explored in a monocytic cell assay . METHODS: Cervical mucus or cervicovaginal fluid was collected from women with (BV) and without BV (nonBV) attending a family planning unit for first trimester abortion . The concentrations of IL-1beta, IL-6, TNF and FFN were determined by quantitative enzyme immunoassays . TNF was determined in 63 women (BV, n=25) out of whom 37 (BV, n=11) were analyzed for IL-1beta and the remaining 26 for IL-6 (BV, n=14) . FFN was determined in another 36 women (BV, n= 19) . The cytokine-inducing capacity of endotoxin-containing cervical mucus and purified endotoxin of Prevotella bivia were studied by an in vitro cell assay using a human monocytic cell line (THP-1) . RESULTS: IL-lbeta and IL-6 were found in almost all women . The levels of IL-1beta, but not IL-6, TNF or FFN, were significantly increased in women with BV compared with the nonBV women (p<0.05) . Purified endotoxin from P . bivia, and cervical mucus from BV women containing high levels of endotoxin were able to induce a cytokine response (IL-6) in monocytic cells in vitro . CONCLUSION: BV is associated with increased levels of IL-1beta in the lower genital tract of pregnant women in the first trimester . The ability of BV-associated endotoxins to induce cytokine production in monocytic cells may partly explain the increased IL-1beta levels. J Gastroenterol Hepatol, 1998 Jan, 13(1), 109 - 11 Spontaneous bacterial peritonitis in fulminant hepatic failure; Poddar U et al.; Ascites may be associated with fulminant hepatic failure (FHF), but spontaneous bacterial peritonitis (SBP) is an extremely rare complication . We report on two patients with FHF who developed SBP . One patient died and the other recovered. J Theor Biol, 1998 Jun 7, 192(3), 403 - 408 Comparison of Stochastic and Deterministic Concepts of Bacterial Lag; Baranyi J; The shortcomings of the traditional deterministic approach to bacterial lag are exposed in this paper . A more precise, stochastic, formulation is put forward which takes account of the variation of the individual cell's lag time . Formulae are given to describe how the lag-distribution of the cells relates to the deterministic population lag commonly used as a practical measure of bacterial lag time. Mol Cell, 1998 Aug, 2(2), 241 - 5 Recognition specificity for the bacterial avirulence protein AvrPto is determined by Thr-204 in the activation loop of the tomato Pto kinase; Frederick RD et al.; The Pto kinase confers resistance in tomato to P . syringae pv . tomato strains expressing the AvrPto protein . Physical interaction of the Pto kinase and AvrPto protein in the plant cell initiates host defense responses . The recognition event between these two proteins is very specific; AvrPto does not interact with other closely related kinases, including the Fen kinase, which shares 80% amino acid identity with Pto . By using Pto-Fen chimeric proteins and site-directed mutagenesis, we found that Thr-204 is required for Pto interaction with AvrPto in a yeast two-hybrid system and for recognition specificity in a tobacco leaf transient assay . Substitution of Thr-204 into the Fen kinase allowed that kinase to interact with AvrPto and to confer an AvrPto-specific defense response in tobacco leaves . Thus, simple mutations appear capable of giving rise to new resistance gene specificities. Can J Microbiol, 1998 Jun, 44(6), 588 - 97 Kinetic analyses of Biolog community profiles to detect changes in inoculum density and species diversity of river bacterial communities; Lawley T et al.; The kinetics of response curves from Biolog community profiles for heterotrophic bacteria from a river in Nova Scotia, Canada have been analyzed to generate lag, slope, and asymptote parameters . The river water samples were treated with one of three supplements of Escherichia coli (in situ levels, 10(3) CFU/mL, or 10(6) CFU/mL) and one of five concentrations of chlorine (0, 1, 3, 5, or 7 ppm) to satisfy a full factorial design . The chlorine treatments decreased the inoculum density by up to 2 log values and decreased the species evenness . The E . coli supplements increased the inoculum density and decreased the species richness . Examination of the asymptotes did not reveal any significant effects owing to E . coli, but differences owing to the chlorine were detected . Analyses of the slopes showed a similar insignificance of the effects of E . coli and a lack of treatment effect owing to chlorine . The lag analyses also showed no significant E . coli effects, but showed a significant effect owing to chlorine . The discrepancy produced with the slope analysis (i.e., no chlorine effect) may represent an anomaly of the Biolog community approach . The use of lag phase was impaired because of the problem of infinite lags from wells that had no response, but a principle component analysis with a reduced set of substrates did suggest some influence of E . coli on the community profile . An examination of the substrates metabolized by the river water compared with pure E . coli revealed that the Biolog profiles of the river communities were not a simple summation of the component parts . In light of the lack of uniformity between these analyses, where the outcome depended on which parameter was used, caution is advised in interpreting Biolog community profiles on the basis of only one parameter. Can J Microbiol, 1998 Jun, 44(6), 537 - 46 Molecular analysis of bacterial isolates and total community DNA from kraft pulp mill effluent treatment systems; Fortin N et al.; Chloroaliphatics are major components of bleached kraft mill effluents . Gene probes and oligonucleotide primers were developed to monitor kraft pulp mill effluent treatment systems for the presence of key genes (dehalogenases) responsible for the dehalogenation of chloroaliphatic organics . The primers were used for polymerase chain reaction (PCR) analysis of genomic DNA extracted from dehalogenating bacterial isolates and from total community DNA extracted from water and sediments of mill effluent treatment system . PCR amplification with oligonucleotide primers designed from dhlB, encoding the haloacid dehalogenase from Xanthobacter autotrophicus, revealed the presence of dehalogenase genes in both aerated lagoons and stabilization basins . Similarly, positive results were obtained with mmoX primers designed from the soluble methane monooxygenase gene of Methylococcus capsulatus Bath . The haloacetate dehalogenase encoding gene (dehH2) from Moraxella sp . was typically not detected in mill effluent treatment systems unless the biomass was selectively enriched . DNA sequence analysis of several PCR fragaments revealed significant similarity to known dehalogenase amd methane monooxygenase genes . The results indicated a broad distribution of known dehalogenation genes and bacteria with chloroorganic-degrading potential in the mill effluent treatment systems. J Biol Chem, 1998 Sep 18, 273(38), 24754 - 9 The sequence, bacterial expression, and functional reconstitution of the rat mitochondrial dicarboxylate transporter cloned via distant homologs in yeast and Caenorhabditis elegans; Fiermonte G et al.; The dicarboxylate carrier (DIC) belongs to a family of transport proteins found in the inner mitochondrial membranes . The biochemical properties of the mammalian protein have been characterized, but the protein is not abundant . It is difficult to purify and had not been sequenced . We have used the sequence of the distantly related yeast DIC to identify a related protein encoded in the genome of Caenorhabditis elegans . Then, related murine expressed sequence tags were identified with the worm sequence, and the murine sequence was used to isolate the cDNA for the rat homolog . The sequences of the worm and rat proteins have features characteristic of the family of mitochondrial transport proteins . Both proteins were expressed in bacteria and reconstituted into phospholipid vesicles where their transport characteristics closely resembled those of whole rat mitochondria and of the rat DIC reconstituted into vesicles . As expected from the role of the DIC in gluconeogenesis and ureogenesis, its transcripts were detected in rat liver and kidney, but unexpectedly, they were also detected in rat heart and brain tissues where the protein may fulfill other roles, possibly in supplying substrates to the Krebs cycle. Biochem Biophys Res Commun, 1998 Aug 28, 249(3), 589 - 94 Bacterial overexpression, purification, and reconstitution of the carnitine/acylcarnitine carrier from rat liver mitochondria; Indiveri C et al.; The carnitine/acylcarnitine carrier from rat liver mitochondria was overexpressed in Escherichia coli . The expressed protein, recovered as inclusion bodies, was solubilized with sarkosyl and purified by Sephadex G-200 and celite chromatography . A yield of 15 mg of purified transport protein per liter of cell culture was obtained . Upon reconstitution into liposomes, the purified carrier catalyzed a {3H}carnitine/carnitine exchange inhibited by maleimides, mercurials, and sulfobetaines . Carnitine esters of various lengths were also transported . The Km for carnitine uptake was 0.47 +/- 0.11 mM, the Vmax of the exchange was 0.78 +/- 0.24 mmol/min per gram of protein, and the Ki for octanoylcarnitine was 13.5 +/- 4.3 microM . The transport properties of the recombinant carrier were virtually identical to those of the native transporter . These studies represent the first overexpression of the functionally active mitochondrial carnitine/acylcarnitine carrier, thus enabling structure/function analysis of this protein by site-directed mutagenesis. Biochem Biophys Res Commun, 1998 Aug 28, 249(3), 573 - 8 Do the bacterial flagellar motor and ATP synthase operate as water turbines? Oplatka A. Despite much progress in the study of the rotary motors ATP synthase (F0F1) and the bacterial flagellar motor, we still cannot answer the most basic and simple question, how the random thermal movement of H+ (or Na+) ions down a pH (or Na+) gradient spins the rotors . I suggest consideration of the possibility that the motors operate like water turbines, i.e., rotation is the outcome of water mini-jets impinging tangentially on the rotors . The vectorial jets are formed when the cations lose part or all of their hydration water upon interacting with a properly positioned site on a protein component which is part of the rotor or is located on a peripheral protein. Neuroimmunomodulation, 1998 Sep-Oct, 5(5), 234 - 40 Bacterial endotoxin induces fos immunoreactivity in primary afferent neurons of the vagus nerve; Gaykema RP et al.; Subdiaphragmatic vagotomy inhibits brain-mediated illness responses to peripherally administered bacterial endotoxin, including fever, hyperalgesia, sickness behavior, and activation of the hypothalamic-pituitary-adrenal axis . However, direct evidence implicating vagal afferents specifically in conveying information about peripheral immune activation to the brain is still lacking . This study assessed whether (1) endotoxin induces the expression of the functional activation marker Fos in the vagal sensory ganglia, and (2) vagotomy abrogates endotoxin-induced Fos expression in these ganglia . Male rats, which had previously received vagotomy or sham surgery, were injected intraperitoneally or intravenously with either endotoxin or saline . Fos immunolabeling was absent in saline-treated rats . In contrast, scattered cells within the vagal sensory ganglia showed Fos immunoreactivity after both intraperitoneal and intravenous endotoxin administration in sham-operated rats . Vagotomy abolished Fos expression after intraperitoneal endotoxin administration, whereas after intravenous administration Fos expression was strongly attenuated, but not eliminated . These findings implicate vagal afferents as a potential signaling pathway to brain regions that generate illness responses to pro-inflammatory mediators. J Antibiot (Tokyo), 1998 Jul, 51(7), 640 - 6 New types of liposidomycins that inhibit bacterial peptidoglycan synthesis and are produced by Streptomyces . I . Producing organism and medium components; Kimura K et al.; Liposidomycins are atypical lipid-bearing nucleoside antibiotics that inhibit bacterial peptidoglycan synthesis . A producing strain was identified as a Streptomyces sp . from its cultural characteristics and physiological properties . It produced new types of liposidomycins that lacked sulfate and/or 3-methylglutaric acid moieties present in known liposidomycins by changing medium components . Sucrose and malt extract were particularly suitable sources for specific production of the new types of liposidomycins. Appl Environ Microbiol, 1998 Sep, 64(9), 3352 - 8 Direct determination of carbon and nitrogen contents of natural bacterial assemblages in marine environments Fukuda R, Ogawa H, Nagata T, Koike I I. In order to better estimate bacterial biomass in marine environments, we developed a novel technique for direct measurement of carbon and nitrogen contents of natural bacterial assemblages . Bacterial cells were separated from phytoplankton and detritus with glass fiber and membrane filters (pore size, 0.8 &mgr;m) and then concentrated by tangential flow filtration . The concentrate was used for the determination of amounts of organic carbon and nitrogen by a high-temperature catalytic oxidation method, and after it was stained with 4',6-diamidino-2-phenylindole, cell abundance was determined by epifluorescence microscopy . We found that the average contents of carbon and nitrogen for oceanic bacterial assemblages were 12.4 +/- 6.3 and 2.1 +/- 1.1 fg cell-1 (mean +/- standard deviation; n = 6), respectively . Corresponding values for coastal bacterial assemblages were 30.2 +/- 12.3 fg of C cell-1 and 5.8 +/- 1.5 fg of N cell-1 (n = 5), significantly higher than those for oceanic bacteria (two-tailed Student's t test; P < 0.03) . There was no significant difference (P > 0.2) in the bacterial C:N ratio (atom atom-1) between oceanic (6.8 +/- 1.2) and coastal (5.9 +/- 1.1) assemblages . Our estimates support the previous proposition that bacteria contribute substantially to total biomass in marine environments, but they also suggest that the use of a single conversion factor for diverse marine environments can lead to large errors in assessing the role of bacteria in food webs and biogeochemical cycles . The use of a factor, 20 fg of C cell-1, which has been widely adopted in recent studies may result in the overestimation (by as much as 330%) of bacterial biomass in open oceans and in the underestimation (by as much as 40%) of bacterial biomass in coastal environments. Appl Environ Microbiol, 1998 Sep, 64(9), 3246 - 55 Rapid determination of bacterial abundance, biovolume, morphology, and growth by neural network-based image analysis Blackburn N, Hagstrom A, Wikner J, Cuadros-Hansson R, Bjornsen PK. Annual bacterial plankton dynamics at several depths and locations in the Baltic Sea were studied by image analysis . Individual bacteria were classified by using an artificial neural network which also effectively identified nonbacterial objects . Cell counts and frequencies of dividing cells were determined, and the data obtained agreed well with visual observations and previously published values . Cell volumes were measured accurately by comparison with bead standards . The survey included 690 images from a total of 138 samples . Each image contained approximately 200 bacteria . The images were analyzed automatically at a rate of 100 images per h . Bacterial abundance exhibited coherent patterns with time and depth, and there were distinct subsurface peaks in the summer months . Four distinct morphological classes were resolved by the image analyzer, and the dynamics of each could be visualized . The bacterial growth rates estimated from frequencies of dividing cells were different from the bacterial growth rates estimated by the thymidine incorporation method . With minor modifications, the image analysis technique described here can be used to analyze other planktonic classes. Plant Cell, 1998 Sep, 10(9), 1439 - 52 A mutation within the leucine-rich repeat domain of the Arabidopsis disease resistance gene RPS5 partially suppresses multiple bacterial and downy mildew resistance genes; Warren RF et al.; Recognition of pathogens by plants is mediated by several distinct families of functionally variable but structurally related disease resistance (R) genes . The largest family is defined by the presence of a putative nucleotide binding domain and 12 to 21 leucine-rich repeats (LRRs) . The function of these LRRs has not been defined, but they are speculated to bind pathogen-derived ligands . We have isolated a mutation in the Arabidopsis RPS5 gene that indicates that the LRR region may interact with other plant proteins . The rps5-1 mutation causes a glutamate-to-lysine substitution in the third LRR and partially compromises the function of several R genes that confer bacterial and downy mildew resistance . The third LRR is relatively well conserved, and we speculate that it may interact with a signal transduction component shared by multiple R gene pathways. J Biochem (Tokyo), 1998 Sep, 124(3), 547 - 56 Prodigiosins uncouple mitochondrial and bacterial F-ATPases: evidence for their H+/Cl- symport activity; Konno H et al.; Prodigiosin, metacycloprodigiosin, and prodigiosin 25-C all inhibited the acidification activity of submitochondrial and bacterial (Escherichia coli) F-ATPases (FoF1-ATPases) strongly (IC50 = 20-30 and 24-30 pmol/mg protein, respectively), without affecting significantly the ATP hydrolysis activity . Their effect on the acidification activity was rapid and reversible, showing non-competitive apparent Ki values of the order of nM to sub-nM . However, unlike FCCP (an ordinary uncoupler of oxidative phosphorylation), they showed no protonophoric activity, as demonstrated by the absence of acceleration of ATP hydrolysis . Prodigiosins also inhibited the acidification of proteoliposomes reconstituted from phospholipids and purified F-ATPase of E . coli, suggesting that their acidification-inhibitory effect is not due to the inhibition of anion channels . They did not, however, inhibit the ATP-dependent formation of membrane potential of F-ATPase vesicles . Furthermore, they inhibited and quickly reversed acidification by F-ATPase only in the presence of chloride, and not in the presence of gluconate anion . Finally, they induced swelling of liposomes and submitochondrial particles in isotonic solution of ammonium chloride but not ammonium gluconate, suggesting that intravesicular entry of Cl- is promoted by prodigiosins . These results suggest that prodigiosins uncouple F-ATPases through promotion of H+/Cl- symport (or OH-/Cl- exchange) across vesicular membranes. J Biochem (Tokyo), 1998 Sep, 124(3), 485 - 90 Control of the unidirectional topological orientation of a cross-linked complex composed of the bacterial photosynthetic reaction center and horse heart cytochrome c reconstituted into proteoliposomes; Ueno T et al.; Control of the unidirectional topological orientation was achieved for a cross-linked complex composed of the bacterial photosynthetic reaction center and horse heart cytochrome c (RC/cyt c) reconstituted into proteoliposomes . Using the method of Ueno et al . {Ueno et al . (1995) Mater . Sci . Eng . C3, 1-6}, we prepared RC/cyt c by conjugating cyt c to the H-subunit of RC of Rhodobacter sphaeroides R-26 using a bifunctional cross-linking reagent, N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP), as previously reported . The freeze-thaw method was used to incorporate RC/cyt c into liposomes that contained dipalmitoyl-L-alpha-phosphatidylcholine and dipalmitoyl-L-alpha-phosphatidylglycerol (1:9) . The topological orientation of RC/cyt c in the proteoliposomes was determined using three methods: (i) release of the cyt c moiety from the proteoliposomes by cleaving the disulfide bond in the linker residue, (ii) electron transfer from free cyt c outside the proteoliposomes to the RC moiety, and (iii) photo-induced membrane potential of RC- and RC/cyt c-reconstituted proteoliposomes . The results indicated that about 90% of the RC/cyt c in proteoliposomes was oriented with the H-subunit exposed on the outside of the liposomes, whereas only about 60% of the RC in proteoliposomes had this orientation . Thus, we successfully controlled the unidirectional topological orientation of the RC moiety in liposomes using the RC/cyt c complex. Allergy, 1998 Aug, 53(8), 786 - 93 A novel dipstick developed for rapid Bet v 1-specific IgE detection: recombinant allergen immobilized via a monoclonal antibody to crystalline bacterial cell-surface layers; Breitwieser A et al.; The incidence of allergy to airborne proteins derived from tree and grass pollen, feces of mites, spores of molds, and pet dander has been increasing over the last decades . Since precise diagnosis is a prerequisite for successful immunotherapy, there is a rising demand for rapid, reliable, and inexpensive screening methods such as dipstick assays . With the purified recombinant major birch-pollen allergen rBet v 1a as model protein, crystalline bacterial cell-surface layers (S-layers) were tested for their applicability as an immobilization matrix for dipstick development . For this purpose, S-layers were deposited on a mechanically stable microporous support, cross-linked with glutaraldehyde, and free carboxylic acid groups of the S-layer protein were activated with carbodiimide . In the present test system, rBet v 1a was immobilized via the monoclonal mouse antibody BIP 1, which, unlike the allergen, is too large to enter the pores of the S-layer lattice, and which therefore formed a closed monolayer on the outermost surface of the crystal lattice . Moreover, BIP 1 is known to modulate IgE binding to the allergen . After incubation of the dipsticks in serum, washing of the reaction zone under tap water, and binding of an anti-IgE alkaline phosphatase conjugate, 5-bromo-4-chloro-3-indolyl phosphate/nitro blue tetrazolium was used as substrate, forming an IgE concentration-dependent colored precipitate on the S-layer surface . The investigation of patient sera previously tested with the CAP system confirmed the specificity of the S-layer-based dipstick assay . Since the dipstick is easy to handle and the whole test procedure takes only 90 min, this test system should be applicable for rapid determination of specific IgE and for first screening in the doctor's practice. Int J Gynaecol Obstet, 1998 Jul, 62(1), 59 - 61 Treatment of bacterial vaginosis with oral or vaginal ornidazole, secnidazole and metronidazole; Saracoglu F et al.; OBJECTIVE: To evaluate the clinical efficacy and tolerance of oral or vaginal ornidazole, secnidazole and metronidazole or their combinations for treatment of bacterial vaginosis . METHOD: In an open, randomized, prospective study, 152 patients with bacterial vaginosis according to Amsel's criteria were included into the study . The patients were divided into eight groups: (1) oral ornidazole 2 x 500 mg/day for 5 days; (2) vaginal ornidazole 500 mg/day for 5 days; (3) oral and vaginal ornidazole for 5 days; (4) oral secnidazole 2 g in a single dose; (5) oral secnidazole 2 g in a single dose and vaginal ornidazole 500 mg/day for 5 days; (6) oral secnidazole 2 g in a single dose and vaginal metronidazole 2 x 500 mg/day for 7 days; (7) oral ornidazole 2 x 500 mg/day for 5 days and vaginal metronidazole 2 x 500 mg/day for 7 days; and (8) vaginal metronidazole 2 x 500 mg/day for 7 days . None of the partners received any treatment . RESULT: We found a 100% cure rate in both oral and vaginal ornidazole and oral secnidazole-vaginal metronidazole groups . CONCLUSION: Vaginal treatments including ornidazole and metronidazole are not as effective as both oral and vaginal drug combinations. Shock, 1998 Aug, 10(2), 97 - 102 Expression of the connexin 43 gene is increased in the kidneys and the lungs of rats injected with bacterial lipopolysaccharide; Fernandez-Cobo M et al.; At the molecular level, the inflammatory response is characterized by changes in gene expression of various organ systems . One gene by which expression has been observed to be altered in the liver during inflammation is connexin (Cx) 32 . Cx genes encode the polypeptide subunits of the hemichannels that comprise gap junctions . In the present study, an increase in the expression of a different Cx gene, Cx43, was observed in the kidney and lung of rats injected with a sublethal dose (1 mg/kg) of bacterial lipolysaccharide (LPS) . To elucidate the possible mechanism by which the Cx43 expression is increased during inflammation, the 5' flanking region of the gene was cloned and coupled to a reporter gene (human growth hormone) . This construct was transfected into cells of renal origin (NRK), which express Cx43 constitutively . The Cx43 promoter activity was indeed found in the cloned region, which contained 725 base pairs upstream of the transcriptional initiation site of the Cx43 gene . The Cx43 promoter activity was found to be increased by incubation of the transfected cells with serum obtained from LPS-treated rats . Moreover, direct incubation of the transfected cells with LPS or interleukin 1beta, but not with other cytokines, was observed to increase the Cx43 promoter activity . These results suggest the expression of Cx43 after administration of LPS is part of the inflammatory response . Moreover, the expression of this gene seems to be mediated by proinflammatory mediators. Genetika, 1998 May, 34(5), 581 - 92 {DNA uptake by bacterial cells: a natural process and laboratory techniques}; Prozorov AA; The mechanisms of DNA uptake during natural transformation of various bacterial species and the methods of the artificial introduction of DNA into bacterial cells and protoplasts are considered . The evolution of views on the bacterial competence and its genetic control during history of investigation of the transformation is discussed. Eur J Immunol, 1998 Aug, 28(8), 2591 - 7 A small domain (6.5 kDa) of bacterial protein G inhibits C3 covalent binding to the Fc region of IgG immune complexes; Munoz E et al.; Attachment of the complement component C3 to antigen-antibody (Ag-Ab) complexes (immune complexes, IC) is the key molecular event responsible for the elimination of many Ag in the form of Ag-Ab-C3b . The CH1 domain and the Fc region of the Ab, which have previously been involved in the binding of C3b, are also the targets of several bacterial IgG-binding proteins, particularly proteins G and A . Here we describe the ability of a small recombinant protein G domain (B2; 6.5 kDa) to inhibit the covalent binding of C3b to the Fc portion of IgG without affecting the binding to the Fab part . Protein G (B2 domain) produced a remarkable inhibition of covalent binding of C3b to IC formed with rabbit IgG, but none with the F(ab')2 fragment, indicating that B2 interferes with the C3b binding to the Fc region . A weak inhibition was observed with IC formed with mouse IgG2b which preferentially binds B2 domain on the CH1 domain of the Fab . To confirm these data, recombinant single-chain Ab devoid of CH1 domains (scAb), and including the rabbit or human Fc portion (hinge-CH2-CH3), were produced and used to form IC . Protein G-B2 domain inhibited C3b binding to IC formed with scAb of either human or rabbit constant regions, supporting the view of a specific blockade of C3b binding to the Fc region . A similar inhibition of C3b binding was observed using protein A instead of protein G B2 domain and the same set of IC . On the CH1 domain, C3b and B2 bind on opposite faces, and therefore do not interfere with each other in their binding . However, B2 domain bound to the inter-CH2-CH3 region impedes the C3b binding to the Fc . This inhibition clarifies the specificity of C3b for the different regions of IgG and explains how bacterial IgG-binding proteins provide the bacteria with a mechanism of evasion from the opsonizing action of complement and contribute to the virulence . This could be a general mechanism of escape because protein G binds the majority of mammalian Ig. J Food Prot, 1998 May, 61(5), 571 - 7 Steam pasteurization of commercially slaughtered beef carcasses: evaluation of bacterial populations at five anatomical locations; Nutsch AL et al.; A steam pasteurization process (patent pending) has been shown to effectively reduce pathogenic bacterial populations on beef tissue and to significantly reduce naturally occurring bacterial populations on commercially slaughtered beef carcasses . The objective of this study was to determine the effectiveness of the steam pasteurization treatment for reducing bacterial populations at several anatomical locations on commerically slaughtered carcasses . Before and after pasteurization treatment (82.2 degrees C, 6.5-s exposure time), a sterile sponge was used to sample 300 cm2 at one of five locations (inside round, loin, midline, brisket, or neck) . Eighty carcasses (40 before treatment and 40 after treatment) were sampled per anatomical location over 2 processing days . Before treatment, aerobic plate counts (APCs) were found to be highest (P < or = 0.01) at the midline (4.5 log10 CFU/100 cm2), intermediate at the inside round, brisket, and neck (ca . 3.8 log10 CFU/100 cm2), and lowest at the loin (3.4 log10 CFU/100 cm2) . After treatment, APCs at all locations were reduced significantly (P < or = 0.01) . The inside round, loin, and brisket had the lowest (P < or = 0.01) APCs (ca . 2.6 log10 CFU/100 cm2), whereas the midline and neck had APCs of 3.1 and 3.3 log10 CFU/100 cm2, respectively . The lower reduction in APCs at the neck area indicated that the treatment may not be as effective there, possibly because of the design of the pasteurization equipment . Generic Escherichia coli populations were low at all locations before treatment, with populations on 32% of all carcasses sampled being less than the detection limit of the study (5.0 CFU/100 cm2) . After treatment, E . coli populations were significantly lower (P < or = 0.01) than populations before treatment and 85% of all carcasses sampled had E . coli populations below the detection limit . The maximum E . coli population detected after treatment was 25 CFU/100 cm2 . For enteric bacterial populations, no differences were observed in the effectiveness of the treatment among the five carcass locations. Biochemistry, 1998 Aug 25, 37(34), 11812 - 20 Effects of hydrogen bonds on the redox potential and electronic structure of the bacterial primary electron donor; Ivancich A et al.; The primary donor, P, of photosynthetic bacterial reaction centers (RCs) is a dimer of excitonically interacting bacteriochlorophyll (BChl) molecules . The two constituents are named PL and PM to designate their close association with the L- and M-subunits, respectively, of the RC protein . A series of site-directed mutants of RCs from Rhodobacter sphaeroides has been constructed in order to model the effects of hydrogen bonding on the redox midpoint potential and electronic structure of P . The leucine residue at position M160 was genetically replaced with eight other amino acid residues capable of donating a hydrogen bond to the C9 keto carbonyl group of the PM BChl a molecule of P . Fourier transform (FT) (pre)resonance Raman spectroscopy with 1064 nm excitation was used to (i) determine the formation and strengths of hydrogen bonds on this latter keto carbonyl group in the reduced, neutral state (PO), and (ii) determine the degree of localization of the positive charge on one of the two constituent BChl molecules of P in its oxidized, radical cation state (P*+) . A correlation was observed between the strength of the hydrogen bond and the increase in PO/P*+ redox midpoint potential . This correlation is less pronounced than that observed for another series of RC mutants where hydrogen bonds to the four pi-conjugated carbonyl groups of P were broken or formed uniquely involving histidinyl residues {Mattioli, T . A., Lin, X., Allen, J . P . and Williams, J . C . (1995) Biochemistry 34, 6142-6152}, indicating that histidinyl residues are more effective in raising the PO/P*+ redox midpoint potential via hydrogen bond formation than are other hydrogen bond-forming residues . In addition, an increase in positive charge localization is correlated with the strength of the hydrogen bond and with the PO/P*+ redox midpoint potential . This latter correlation was analyzed using an asymmetric bacteriochlorophyll dimer model based on Huckel-type molecular orbitals in order to obtain estimates of certain energetic parameters of the primary donor . Based on this model, the correlation is extrapolated to the case of complete localization of the positive charge on PL and gives a predicted value for the P/P+ redox midpoint potential similar to that experimentally determined for the Rb . sphaeroides HL(M202) heterodimer . The model yields parameters for the highest occupied molecular orbital energies of the two BChl a constituents of P which are typical for the oxidation potential of isolated BChl a in vitro, suggesting that the protein, as compared to many solvents, does not impart atypical redox properties to the BChl a constituents of P. Biochemistry, 1998 Aug 25, 37(34), 11732 - 44 Interaction site for soluble cytochromes on the tetraheme cytochrome subunit bound to the bacterial photosynthetic reaction center mapped by site-directed mutagenesis; Osyczka A et al.; The crystallographic structure of the Blastochloris (formerly called Rhodopseudomonas) viridis tetraheme cytochrome subunit bound to the photosynthetic reaction center (RC) suggests that all four hemes are located close enough to the surface of the protein to accept electrons from soluble cytochrome c2 . To identify experimentally the site of this reaction we prepared site-directed mutants of Rubrivivax gelatinosus RCs with surface charge substitutions in the bound cytochrome subunit and studied the kinetics of their reduction by soluble cytochromes (mitochondrial horse cytochrome c, Blc . viridis cytochrome c2, and Rvi . gelatinosus cytochrome c8) . In comparison with the wild-type, the mutants E79K (glutamate-79 substituted by lysine), E93K (glutamate-93 substituted by lysine), and E85K (glutamate-85 substituted by lysine) located near the solvent-exposed edge of low-potential heme 1, the fourth heme from the special pair of bacteriochlorophyll, exhibited decreased second-order rate constants for the reaction between the tetraheme subunit and the soluble cytochromes . Double charge substitutions in this region: E79K/E85K (glutamate-79 and -85 both replaced by lysine) and E93K/E85K (glutamate-93 and -85 both replaced by lysine) appeared to show an additive inhibitory effect . Mutations in other charged regions did not alter the kinetics of electron transfer between bound and soluble cytochromes . In light of the available structural information on Blc . viridis RC, these results indicate that the cluster of acidic residues immediately surrounding the distal heme 1 of the RC-bound tetraheme subunit forms an electrostatically favorable binding site for soluble cytochromes . Thus, all four hemes in the subunit seem to be directly involved in the electron transfer toward the photo-oxidized special pair of bacteriochlorophyll . On the basis of these findings, a model is proposed for the hypothetical cytochrome c2-RC transient complex for Blc . viridis. Br J Surg, 1998 Aug, 85(8), 1103 - 6 Evidence that aminoguanidine inhibits endotoxin-induced bacterial translocation; Kavuklu B et al.; BACKGROUND: The role of inducible nitric oxide synthase (iNOS) in endotoxin-induced bacterial translocation was investigated by using its specific blocker aminoguanidine in 46 albino mice (25-35 g) allocated into four groups . METHODS: The first group received intraperitoneal saline (control; 0.9 per cent w v(-1) sodium chloride 1 ml kg(-1); n=6), the second group intraperitoneal endotoxin (Escherichia coli lipopolysaccharide 055:B5 20 mg kg(-1); n=19), the third group intraperitoneal aminoguanidine (20 mg kg(-1), 20 min before and 12 h after saline; n=6) and the fourth group both endotoxin and aminoguanidine intraperitoneally (n=15) . Some 24 h later, the animals were anaesthetized with ether and blood samples were collected by cardiac puncture together with mesenteric lymph node (MLN), spleen and liver specimens under aseptic conditions . Specimens were then cultured to determine the presence of colony-forming units as an index of bacterial translocation . RESULTS: No bacterial growth was detected in samples from the first and third groups . Colony-forming bacteria were found in ten of 14 MLN samples, eight of 14 spleens, four of 14 livers and three of 14 peripheral blood samples in the second group, with E . coli being the predominant pathogen . In contrast, in the fourth group, colony-forming bacteria were found in only three of 14 MLN samples (P=0.02 versus the second group), three of 14 spleens and one of 14 liver specimens . None of the values in the fourth group was significantly different from those in the saline control group . CONCLUSION: The inhibition of iNOS during endotoxaemia by its specific blocker aminoguanidine attenuates the incidence of bacterial translocation in mice . These results may be exploited clinically for the prophylaxis and treatment of septic states. J Appl Microbiol, 1998 Jun, 84(6), 1138 - 48 Solar disinfection of drinking water contained in transparent plastic bottles: characterizing the bacterial inactivation process; McGuigan KG et al.; A series of experiments is reported to identify and characterize the inactivation process in operation when drinking water, heavily contaminated with a Kenyan isolate of Escherichia coli, is stored in transparent plastic bottles that are then exposed to sunlight . The roles of optical and thermal inactivation mechanisms are studied in detail by simulating conditions of optical irradiance, water turbidity and temperature, which were recorded during a series of solar disinfection measurements carried out in the Kenyan Rift Valley . Optical inactivation effects are observed even in highly turbid water (200 ntu) and at low irradiances of only 10 mW cm-2 . Thermal inactivation is found to be important only at water temperatures above 45 degrees C, at which point strong synergy between optical and thermal inactivation processes is observed . The results confirm that, where strong sunshine is available, solar disinfection of drinking water is an effective, low cost method for improving water quality and may be of particular use to refugee camps in disaster areas . Strategies for improving bacterial inactivation are discussed. Trends Microbiol, 1998 Jul, 6(7), 269 - 75 Bacterial death by DNA gyrase poisoning; Couturier M et al.; DNA gyrase is an essential topoisomerase that is found in all bacteria and is the target of potent antibiotics, such as the quinolones . By creating DNA lesions and inducing the bacterial SOS response, these drugs are not only highly cytotoxic but also mutagenic . Discovery and analysis of natural molecules with anti-gyrase activities, such as the CcdB or microcin B17 proteins, hold promise for understanding further topoisomerase reactions and for the design of new antibiotics. Biochem J, 1998 Sep 1, 334 ( Pt 2), 387 - 92 Enzymological characterization of the nuclease domain from the bacterial toxin colicin E9 from Escherichia coli; Pommer AJ et al.; The cytotoxicity of the bacterial toxin colicin E9 is due to a non-specific DNase that penetrates the cytoplasm of the infected organism and causes cell death . We report the first enzymological characterization of the overexpressed and purified 15 kDa DNase domain (E9 DNase) from this class of toxin . CD spectroscopy shows the E9 DNase to be structured in solution, and analytical ultracentrifugation data indicate that the enzyme is a monomer . The nuclease activity of the E9 DNase was compared with the well-studied, non-specific DNase I by using a spectrophotometric assay with calf thymus DNA as the substrate . Both enzymes require divalent metal ions for activity but, unlike DNase I, the E9 DNase is not activated by Ca2+ ions . Somewhat surprisingly, the E9 DNase shows optimal activity and linear kinetics in the presence of transition metals such as Ni2+ and Co2+ but displays non-linear kinetics with metals such as Mg2+ and Ca2+ . Conversely, Ni2+ and other transition metals showed poor activity in a plasmid-based nicking assay, yielding significant amounts of linearized plasmid, whereas Mg2+ was very active, with the main intermediate being open-circle DNA . The results suggest that, on entry into bacterial cells, the E9 DNase is likely to exhibit primarily Mg2+-dependent nicking activity against chromosomal DNA, although other metals could also be utilized to introduce both single- and double-strand cleavages. FEBS Lett, 1998 Jul 24, 431(3), 339 - 42 Targeting signals for a bacterial Sec-independent export system direct plant thylakoid import by the delta pH pathway; Wexler M et al.; Preproteins targeted to the Sec-independent protein transport systems of plant thylakoids and of bacteria both have unusual transfer peptides bearing a consensus twin-arginine motif . Possible mechanistic similarity between the two Sec-independent transport pathways was investigated by assessing the ability of bacterial twin-arginine transfer peptides to direct thylakoid import . High efficiency import was observed . This process was demonstrated to occur specifically via the Sec-independent deltapH pathway and to depend on an intact twin-arginine motif on the transfer peptide . These results provide strong evidence for the operation of mechanistically related Sec-independent protein transport pathways in chloroplasts and bacteria. Infect Immun, 1998 Sep, 66(9), 4517 - 21 The Helicobacter pylori UreI protein is not involved in urease activity but is essential for bacterial survival in vivo; Skouloubris S et al.; We produced defined isogenic Helicobacter pylori ureI mutants to investigate the function of UreI, the product of one of the genes of the urease cluster . The insertion of a cat cassette had a strong polar effect on the expression of the downstream urease genes, resulting in very weak urease activity . Urease activity, measured in vitro, was normal in a strain in which ureI was almost completely deleted and replaced with a nonpolar cassette . In contrast to previous reports, we thus found that the product of ureI was not necessary for the synthesis of active urease . Experiments with the mouse-adapted H . pylori SS1 strain carrying the nonpolar ureI deletion showed that UreI is essential for H . pylori survival in vivo and/or colonization of the mouse stomach . The replacement of ureI with the nonpolar cassette strongly reduced H . pylori survival in acidic conditions (1-h incubation in phosphate-buffered saline solution at pH 2.2) in the presence of 10 mM urea . UreI is predicted to be an integral membrane protein and may therefore be involved in a transport process essential for H . pylori survival in vivo.
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