Scand J Gastroenterol, 1998 Jul, 33(7), 691 - 700 Involvement of nitric oxide and prostaglandins in gastroprotection induced by bacterial lipopolysaccharide; Konturek PC et al.; BACKGROUND: Lipopolysaccharide (LPS) has been proposed to act as one of the pathogens in endotoxemia-induced gastric lesions, but its action on mucosal integrity has not been fully clarified . METHODS: We compared the effects of LPS originating from Escherichia coli and the chemical donor of nitric oxide (NO), S-nitroso-acetylpenicillamine (SNAP), on acute gastric lesions induced by 100% ethanol, mucosal blood flow (GBF), and mucosal generation of prostaglandin E2 (PGE2) and examined the expression of constitutive NO synthase (cNOS) and inducible NO synthase (iNOS) mRNA in the gastric mucosa of rats treated with LPS, by using reverse transcription polymerase chain reaction (RT-PCR) . RESULTS: LPS (0.01-1.0 mg/kg) or SNAP (0.37-3.0 mg/kg) given intraperitoneally, dose-dependently prevented ethanol-induced mucosal lesions, and these protective effects were accompanied by a significant increase in the GBF and excessive mucosal release of NO . Suppression of NOS activity by NG-nitro-L-arginine methyl ester (L-NAME) (20mg/kg intravenously) or L-NG-(1-iminoethyl)-lysine (L-NIL) (30mg/kg intraperitoneally) and NOS induction by treatment with dexamethasone (2 mg/kg intraperitoneally) reversed the protective and hyperemic effects of LPS, and this reversal by L-NAME was significantly antagonized by addition of the substrate for NOS, L-arginine, but not D-arginine . Both LPS and SNAP increased PGE2 generation significantly, and this effect was reduced by pretreatment with L-NAME, L-NIL, or dexamethasone . Expression of cNOS was detected by RT-PCR in the intact mucosa, but intense signals for expression of both cNOS and iNOS were detected in the mucosa of LPS-treated rats . CONCLUSIONS: Parenteral LPS, similarly to the chemical NO donor, SNAP, protects the gastric mucosa against ethanol-induced damage via an increase in GBF mediated by NO due to the activation of arginine-NO system and possibly also enhanced generation of PGE2. J Immunol, 1998 Aug 15, 161(4), 1930 - 8 CXCR1 and CXCR2 are rapidly down-modulated by bacterial endotoxin through a unique agonist-independent, tyrosine kinase-dependent mechanism; Khandaker MH et al.; The expression of the seven-transmembrane domain chemokine receptors CXCR1 and CXCR2 modulates neutrophil responsiveness to the chemoattractant IL-8 and a number of closely related CXC chemokines . In the present study, we investigated the mechanism by which bacterial LPS induces the down-modulation of IL-8 responsiveness and CXCR1 and CXCR2 expression on human neutrophils . Treating neutrophils with LPS reduced IL-8R expression to 55 +/- 5% of the control within 30 min and to 23 +/- 2% within 1 h of stimulation . Furthermore, this down-modulation could not be attributed to increased concentrations of IL-8, TNF-alpha, or IL-1beta, since ELISA studies indicated that LPS-stimulated neutrophils did not release detectable amounts of these proteins before 2 h poststimulation . The tyrosine kinase (TK) inhibitors genistein and herbimycin A attenuated the LPS-mediated down-modulation of CXCR1 and CXCR2, indicating that the activation of a TK is required for LPS to mediate its effect . The effect of LPS on receptor expression paralleled the hyperphosphorylation of the protein TK p72syk . Although IL-8 induced a comparable down-modulation of CXCR1 and CXCR2, TK inhibitors did not attenuate this effect . These studies provide the first evidence of an agonist-independent, TK-dependent pathway of chemokine receptor regulation by endotoxin. Chem Biol, 1998 Aug, 5(8), R181 - 6 Computational analysis of bacterial sulfatases and their modifying enzymes; Schirmer A et al.; The sequence analysis of enzymes that might modify bacterial sulfatases should be useful in the task of identifying the human sulfatase-modifying homologs--enzymes that are defective in the rare inherited disease multi-sulfatase deficiency. FEBS Lett, 1998 Jul 31, 432(1-2), 9 - 12 Useful 1O2 (1delta g) generator, 3-(4'-methyl-1'-naphthyl)-propionic acid, 1',4'-endoperoxide (NEPO), for dioxygenation of squalence (a skin surface lipid) in an organic solvent and bacterial killing in aqueous medium; Nakano M et al.; 3-(4'-Methyl-1'-naphthyl)-propionic acid, 1',4'-endoperoxide (NEPO) provides singlet state of oxygen (1O2, 1delta g) at 37 degrees C in sodium phosphate buffer (pH 7.2), acetate buffer (pH 4.5), methanol or chloroform, through the retro-Diels-Alder reaction . The total amount of 1O2 generated by NEPO was calculated using the following equation: {1O2}= {NEPO}0{1-exp(-kt)}, where {1O2}, {NEPO}0 and k are the total amount of 1O2 produced during the time t, initial concentration of NEPO and the first-order reaction rate constant, respectively . When squalene was exposed to 1O2 which was generated thermolytically from NEPO, it was oxidized to three hydroperoxides, mono-, di- and tri-hydroperoxides, in amounts proportional to the dose of NEPO . The oxidizability of squalene was much more extensive compared with unsaturated phospholipids . Additionally, when wild-type E . coli and lycopene-producing mutant E . coli were exposed to NEPO-derived 1O2, there was significant loss of viability of wild-type E . coli but no significant loss of viability in lycopene-producing strain, suggesting that lycopene by scavenging 1O2 protected E . coli against 1O2 toxicity. EMBO J, 1998 Aug 17, 17(16), 4704 - 11 AMPA receptors and bacterial periplasmic amino acid-binding proteins share the ionic mechanism of ligand recognition; Lampinen M et al.; In order to identify key structural determinants for ligand recognition, we subjected the ligand-binding domain of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-selective glutamate receptor GluR-D subunit to site-directed mutagenesis . Based on the analysis of the {3H}AMPA-binding properties of the mutated binding sites, we constructed a revised three-dimensional model of the ligand-binding site, different in many respects from previously published models . In particular, our results indicate that the residues Arg507 and Glu727 represent the structural and functional correlates of Arg77 and Asp161 in the homologous bacterial lysine/ornithine/arginine-binding protein and histidine-binding protein, and directly interact with the alpha-carboxyl and alpha-amino group of the bound ligand, respectively . In contrast, Glu424, implicated previously in ionic interactions with the alpha-amino group of the agonist, is unlikely to have such a role in ligand binding . Our results indicate that glutamate receptors share with the bacterial polar amino acid-binding proteins the fundamental mechanism of amino acid recognition. Surgery, 1998 Aug, 124(2), 284 - 90 Immunoglobulin A supplementation abrogates bacterial translocation and preserves the architecture of the intestinal epithelium; Dickinson EC et al.; BACKGROUND: Breast milk has been shown to prevent gut-origin infections in neonates through undefined mechanisms . Putative protective factors in breast milk include immunoglobulin (Ig)A, IgG, and lactoferrin . We examined their role in bacterial translocation in neonatal rabbits . METHODS: IgA, IgG, and lactoferrin were isolated from rabbit breast milk through gel filtration and ion-exchange chromatography . Neonates were randomized to receive breast milk, formula alone, or formula supplemented with IgA, IgG, or lactoferrin . Quantitative cultures were performed on day 7 for bacterial translocation . Hematoxylin-eosin-stained sections of distal ileum were examined by light microscopy . Transmucosal bacterial passage was determined in vitro, and the ileal mucosal membranes were examined by confocal microscopy . RESULTS: IgA supplementation abrogated bacterial translocation . IgG and lactoferrin had no significant effect . Neonates that received IgA or breast milk gained more weight than those in the other groups . IgA reduced transmucosal bacterial passage in vitro . In contrast to the normal-appearing distal ileum of neonates fed breast milk, intestinal epithelium from neonates that received formula or formula with IgG or IgA demonstrated prominent vacuoles by light microscopy . Those fed formula alone or formula with lactoferrin had slightly shortened villi . CONCLUSIONS: IgA supplementation prevents bacterial translocation by enhancing gut mucosal barrier function. Poult Sci, 1998 Aug, 77(8), 1139 - 42 Bacterial respiratory disease of poultry; Glisson JR; Bacterial pathogens play an important role in causing respiratory disease in domestic poultry species . In many cases, the bacterial component of a respiratory disease colonizes the respiratory system only after a primary viral or environmental insult . Colonization of the airsacs of a chicken by Escherichia coli following an infectious bronchitis virus infection is an example of secondary bacterial invasion . In other cases, the bacterial component of the respiratory disease is the primary initiating cause of the disease . Examples of primary bacterial respiratory disease are infectious coryza in chickens and fowl cholera in chickens and turkeys. J Biol Chem, 1998 Aug 21, 273(34), 21800 - 7 Apolipoprotein B gene expression in a series of human apolipoprotein B transgenic mice generated with recA-assisted restriction endonuclease cleavage-modified bacterial artificial chromosomes . An intestine-specific enhancer element is located between 54 and 62 kilobases 5' to the structural gene; Nielsen LB et al.; Prior studies have established that the expression of the human apolipoprotein B (apoB) gene in the intestine is dependent on DNA sequences located a great distance from the structural gene . To identify the location of those sequences, we used recA-assisted restriction endonuclease (RARE) cleavage to truncate the 5'- or 3'-flanking sequences from a 145-kilobase (kb) bacterial artificial chromosome spanning the entire human apoB gene . Seven RARE cleavage- modified bacterial artificial chromosomes with different lengths of flanking sequences were used to generate transgenic mice . An analysis of those mice revealed that as little as 1.5 kb of 3' sequences or 5 kb of 5' sequences were sufficient to confer apoB expression in the liver . In contrast, apoB gene expression in the intestine required DNA sequences 54-62 kb 5' to the structural gene . Those sequences retained their ability to direct apoB expression in the intestine when they were moved closer to the gene . These studies demonstrate that the intestinal expression of the apoB gene is dependent on DNA sequences located an extraordinary distance from the structural gene and that the RARE cleavage/transgenic expression strategy is a powerful approach for analyzing distant gene-regulatory sequences. Acta Biochim Pol, 1998, 45(1), 233 - 40 A method for isolation of plasmid DNA replication intermediates from unsynchronized bacterial cultures for electron microscopy analysis; Srutkowska S et al.; Electron microscopy is a powerful technique for analysis of DNA replication intermediates . However, isolation of replicating DNA molecules from living cells is tricky and difficult, especially in the case of small DNA molecules (such as bacterial plasmids) whose initiation of replication is not easily synchronized . Here a relatively simple and rapid method for efficient isolation of replicating plasmid molecules from unsynchronized Escherichia coli cultures is described . The efficiency of this procedure is high enough for electron microscopy analysis of plasmid replication intermediates appearing in living cells in normal growth conditions . Under optimal conditions, using standard procedures of isolation of plasmid DNA, it is possible to achieve a content of only as few as 0.02 percent of replication intermediates in a plasmid DNA sample . The described method allowed us to enrich up to 100-fold the fraction of replication intermediates suitable for microscopic analysis among all plasmid molecules. RNA, 1998 Aug, 4(8), 937 - 47 Identification by modification-interference of purine N-7 and ribose 2'-OH groups critical for catalysis by bacterial ribonuclease P; Kazantsev AV et al.; The RNA subunit of bacterial ribonuclease P is a catalytic RNA that cleaves precursor tRNAs to generate mature tRNA 5' ends . A self-cleaving RNase P RNA-substrate conjugate was used in modification-interference analysis to identify purine N-7 and ribose 2'-hydroxyl functional groups that are critical to catalysis . We identify six adenine N-7 groups and only one 2'-hydroxyl that, when substituted with 7-deazaadenine or 2'-deoxy analogues, respectively, reduce the RNase P catalytic rate approximately 10-fold at pH 8 and limiting concentration of magnesium . Two sites of low-level interference by phosphorothioate modification were detected in addition to the four sites of strong interference documented previously . These modification-interference results, the absolute phylogenetic conservation of these functional groups in bacterial RNase P RNA, their proximity to the substrate-phosphate in the tertiary structure of the ribozyme-substrate complex, and the importance of some of the sites for binding of catalytic magnesium all implicate these functional groups as components of the RNase P active site . Five of the 7-deazaadenine interferences are suppressed at pH 6, where the hydrolytic step is rate-limiting, or at saturating concentrations of magnesium . We propose, therefore, that these base functional groups are specifically engaged in the catalytic center of RNase P RNA, possibly by involvement in magnesium-dependent folding . One 7-deazaadenine interference and one 2'-deoxy-interference, although partially suppressed at pH 6, are not suppressed at saturating magnesium concentrations . This implicates these groups in magnesium-independent folding of the catalytic substructure of the ribozyme. Zh Mikrobiol Epidemiol Immunobiol, 1998 May-Jun, (3), 47 - 51 {Chronic bacterial prostatitis as a manifestation of secondary immunodeficiency state}; Gus'kov AR et al.; The clinico-immunological examination of 57 patients with chronic bacterial prostatitis was carried out . The clinical analysis made it possible to divide the patients into 3 groups characterized by the presence of chronic inflammatory diseases of other organs which had appeared before (group 1) or after (group 2) the manifestation of the symptoms of prostatitis, aw well as by the absence of concomitant inflammatory diseases (group 3) . At the same time these patients were found to have changes in their immune status, most pronounced in patients of groups 1 and 2 . The clinico-immunological analysis of the patients with chronic bacterial prostatitis revealed the fact that chronic bacterial prostatitis was a chronic inflammatory process linked with changes in the immune system; these changes had the signs of secondary immunodeficiency and required immunocorrective therapy. Braz J Med Biol Res, 1998 Apr, 31(4), 515 - 8 The effect of bacterial lipopolysaccharide on gastric emptying in rats suffering from moderate renal insufficiency; Rigatto SZ et al.; The objective of the present study was to evaluate the response of rats suffering from moderate renal insufficiency to bacterial lipopolysaccharide (LPS, or endotoxin) . The study involved 48 eight-week-old male SPF Wistar rats (175-220 g) divided into two groups of 24 animals each . One group underwent 5/6 nephrectomy while the other was sham-operated . Two weeks after surgery, the animals were further divided into two subgroups of 12 animals each and were fasted for 20 h but with access to water ad libitum . One nephrectomized and one sham-treated subgroup received E . coli LPS (25 micrograms/kg, i.v.) while the other received a sterile, pyrogen-free saline solution . Gastric retention (GR) was determined 10 min after the orogastric infusion of a standard saline test meal labeled with phenol red (6 mg/dl) . The gastric emptying of the saline test meal was studied after 2 h . Renal function was evaluated by measuring the plasma levels of urea and creatinine . The levels of urea and creatinine in 5/6 nephrectomized animals were two-fold higher than those observed in the sham-operated rats . Although renal insufficiency did not change gastric emptying (median %GR = 26.6 for the nephrectomized subgroup and 29.3 for the sham subgroup), LPS significantly retarded the gastric emptying of the sham and nephretomized groups (median %GR = 42.0 and 61.0, respectively), and was significantly greater (p < 0.01) in the nephrectomized rats . We conclude that gastric emptying in animals suffering from moderate renal insufficiency is more sensitive to the action of LPS than in sham animals. Biochemistry, 1998 Aug 11, 37(32), 11366 - 75 Molybdopterin radical in bacterial aldehyde dehydrogenases; Luykx DM et al.; The EPR spectra of three different molybdoprotein aldehyde dehydrogenases, one purified from Comamonas testosteroni and two purified from Amycolatopsis methanolica, showed in their oxidized state a novel type of signal . These three enzymes contain two different {2Fe-2S} centers, one flavin and one molybdopterin cytosine dinucleotide, as cofactors all of which are expected to be EPR silent in the oxidized state . The new EPR signal is isotropic with g = 2.004 both at X-band and Q-band frequencies, consists of six partially resolved lines, and shows Curie temperature behavior suggesting that the signal is due to an organic radical with S = 1/2 . The EPR spectra of Comamonas testosteroni aldehyde dehydrogenase obtained after cultivation in media containing 15NH4Cl and/or after substitution of H2O for D2O show the presence of both nitrogen and proton hyperfine interactions . Simulations of the spectra of the four possible isotope combinations yield a single set of hyperfine coupling constants . The electron spin shows hyperfine interaction with a single I = 1 (0.9 mT) ascribed to a N nucleus, with a single I = 1/2 (1.5 mT) ascribed to one nonexchangeable H nucleus, and with two, exchangeable, identical I = 1/2 spins (0.6 mT) ascribed to two identical exchangeable protons . Taken together, the observations and simulations rule out amino acid residues or flavin as the origin of the radical . The values of the various hyperfine coupling constants are consistent with the properties expected for a molybdenum(VI)-trihydropterin radical in which the N5 atom is engaged in two hydrogen-bonding interactions with the protein . The majority of the electron (spin) density of the radical is located at and around the N5 atom and at the proton bound to the C6 atom of the pterin ring . The EPR spectrum of the molybdopterin radical broadens above 65 K and is no longer detectable above 168 K, indicating that it is not magnetically isolated . The line broadening is ascribed to cross-relaxation with a nearby, rapidly relaxing, oxidized {2Fe-2S} center involving its magnetic S = 1 excited state in this process . The amount of radical was apparently not changed by addition of aldehydes or oxidants, but it disappeared upon reduction by sodium dithionite . Therefore, whether the molybdenum(VI) trihydropterin radical as detected here is a functional intermediate in catalysis remains to be investigated further. Int J Oral Maxillofac Surg, 1998 Aug, 27(4), 305 - 9 Inductive properties of recombinant human BMP-2 produced in a bacterial expression system; Kubler NR et al.; Recombinant human BMP-2, produced in E . coli, refolded and concentrated to a purity of more than 98%, has been demonstrated to be biologically active . In vitro, amounts of 0.4 microg BMP-2 or more induced new cartilage formation in 27 out of 47 samples of a neonatal muscle tissue assay, with chondroneogenesis occurring 14 days after a four-hour contact between BMP-2 and the muscle tissue . In vivo, BMP-2 was implanted in the thigh muscle of ICR mice for a period of three weeks . Amounts of 4 microg BMP-2 and more showed heterotopic bone formation in 15 out of 17 samples . When BMP-2 was combined with a collagen carrier, amounts of 0.4 microg protein or more induced heterotopic bone formation in 30 out of 33 samples four weeks after the implantation in the abdominal wall of Sprague-Dawley rats . The results show that the E . coli-derived BMP-2 was active in different assay systems in concentrations equal to those required with mammalian cell-expressed BMP-2 . It could also be demonstrated that a single morphogen (BMP-2) is enough to initiate the differentiation process associated with bone induction . The presented bacterial expression system also offers the opportunity to produce large quantities of recombinant BMP-2 for clinical applications. Biophys Chem, 1998 Jul 13, 73(1-2), 23 - 9 Osmotic compaction of supercoiled DNA into a bacterial nucleoid; Odijk T; A theory is presented of the phase separation of supercoiled DNA into a nucleoid in a bacterial cell . The suspension consists of DNA interacting with globular proteins in excess salt . A cross virial between DNA and a protein is computed as well as the DNA self-energy arising from excluded volume . The cellular parameters of Escherichia coli would appear to be compatible with the thermodynamic equilibrium derived theoretically . The state of superhelical DNA in the nucleoid could be liquid crystalline and rippled. Eur J Surg, 1998 Jun, 164(6), 449 - 56 Association between transfusion of stored blood and infective bacterial complications after resection for colorectal cancer; Edna TH et al.; OBJECTIVE: To examine the association between blood transfusion and bacterial infective complications after resection for colorectal adenocarcinoma . DESIGN: Retrospective cohort study . SETTING: District hospital; Norway . SUBJECTS: 446 consecutive patients having resection of colorectal adenocarcinoma . MAIN OUTCOME MEASURES: Postoperative bacterial infective morbidity in hospital . RESULTS: 112 patients (25%) developed postoperative infections in hospital . Univariate analysis showed that the development of infection was significantly associated with increasing age (p=0.02), rectal compared with colonic cancer (p=0.002), preoperative radiotherapy (p=0.005), blood loss during operation (p=0.001), the extent of the primary tumour (T stage): T4 compared with T1-T3 (p=0.004), the presence of regional lymph node metastasis (N stage): N1-N3 compared with N0 (p=0.01), operating surgeon 1 (p=0.009), operating surgeon 2 (p=0.03), and blood transfusion (p < 0.001) . Multivariate logistic regression analysis showed that the following variables were independent predictors of infection: age, rectal compared with colonic cancer, T stage, N stage, and blood transfusion . The corrected odds ratios for infection were 1.5 (95% CI 0.8 to 2.8) when 1-3 units of blood were given and 3.1 (95% CI 1.6 to 6.0) when more than three units were given . Storage time did not affect the rate of postoperative infections in patients given transfusions . CONCLUSION: Transfusion of non-filtered stored allogeneic blood suspended in saline-adenine-glucose-mannitol is an independent risk factor for the development of postoperative infections in hospital in patients having a resection of colorectal cancer. J Biolumin Chemilumin, 1998 May-Jun, 13(3), 117 - 23 Preliminary electrochemiluminescence studies of metal ion-bacterial diazoluminomelanin (DALM) interactions; Bruno JG et al.; Electrochemiluminescence (ECL) studies of the chemiluminescent (CL) polymer diazoluminomelanin (DALM) biosynthesized in nitrate reductase transfected Escherichia coli JM109 bacteria revealed noteworthy anodic ECL and even more intense cathodic ECL . Bacterial DALM (BD) ECL was also assessed in the presence of 100 ppm of 33 different metal and non-metal ions which revealed specific anodic, but not cathodic, enhancements of BD ECL with Ag+, Hg2+ and Ru3+ . The precursors and intermediate polymers which comprise DALM, such as luminol, 3-amino-L-tyrosine (3-AT), aminomelanin (AM) and diazomelanin (DM) were screened for ECL enhancement against the same set of elemental ions . Significant anodic ECL enhancements were observed for luminol with Hg2+ in the presence of tripropylamine (TPA), but not for any other DALM component in combination with other elemental ions, either anodically or cathodically . Comparison of BD with luminol in the presence and absence of TPA and Hg2+ revealed very different ECL activity patterns and suggested different mechanisms for BD and luminol ECL. J Dent Hyg, 1998 Summer, 72(3), 19 - 23 Bacterial contamination of scrub jackets during dental hygiene procedures; Huntley DE et al.; PURPOSE: The purpose of this study was to assess bacterial contamination of uniforms by aerosols produced during dental hygiene procedures, including examination, hand and ultrasonic scaling, and polishing . METHODS: Sterile milipore filters were taped to long-sleeved scrub jackets of 26 senior dental hygiene students and worn during patient appointments . Filters were removed at the end of the appointment and cultured to determine bacterial contamination on the dominant arm, non-dominant arm, and chest . RESULTS: Analysis of filter position by procedure with SPSS MANOVA showed a statistically significant difference (1.95, df = 9,299, p = .045) . Univariate statistics showed that filters on the dominant arm (p = .013) and non-dominant arm (p = .030) had significantly higher colony forming unit/filter for ultrasonic scaling than for examination, while chest did not (p = .154) . CONCLUSION: Aerosol contamination is produced during dental hygiene procedures, even examination and hand scaling . The number of micro-organisms is higher on the sleeves than the chest of scrub jackets, and is higher when ultrasonic or sonic scalers or air polishers are used. J Immunol Methods, 1998 May 1, 214(1-2), 149 - 63 Bacterial lipopolysaccharide contamination of commercial collagen preparations may mediate dendritic cell maturation in culture; Suri RM et al.; Dendritic cells (DC) are potent antigen presenting cells, which are responsible for the initiation of naive T and T-dependent immune responses . The present studies were based upon recent reports that commercial collagen I preparations induce the maturation of human DC in vitro . We show that human blood monocyte-derived (GM-CSF and IL-4 cultured) DC pulsed on collagen I-coated plates undergo a dose-dependent increase in stimulatory capacity in oxidative mitogenesis assays . This is accompanied by the upregulation of costimulatory molecules (CD40, CD80, CD86), CD25, ICAM-1 and the DC-specific marker CD83 . The maturation effect is more potent than TNF-alpha, which is a known mediator of DC function . However, bacterial lipopolysaccharide (LPS), a powerful inducer of DC maturation, was found to be present at very high levels in one commercial collagen solution that was tested . The effect of LPS upon DC maturation was similar to culture with collagen . Furthermore, a different collagen I preparation with low levels of LPS contamination was less effective at inducing DC maturation, while spiking the collagen solution with LPS prior to plastic coating equalised these effects . Finally, human monocyte-derived DC were found not to express typical collagen receptors VLA-1, 2 and 3 . We therefore propose that LPS contamination may at least partially explain reported collagen I induced DC maturation. Aliment Pharmacol Ther, 1998 Jan, 12(1), 99 - 104 Drug-induced hypochlorhydria causes high duodenal bacterial counts in the elderly; Pereira SP et al.; BACKGROUND: Small bowel bacterial overgrowth secondary to drug-induced hypochlorhydria may be of particular importance in the elderly, in whom anti-ulcer drugs are commonly prescribed and the consequences of malabsorption may be severe . METHODS: Duodenal aspirates were obtained from elderly individuals before (n = 24) and during a 2-month treatment course with either omeprazole (20 mg daily; n = 8) or ranitidine (300 mg b.d.; n = 6), and from six patients with small bowel bacterial overgrowth who had diarrhoea and malabsorption . RESULTS: Before treatment, duodenal bacterial counts were normal (< 10(4) colony forming units/mL) in 23 elderly subjects (96%) . However, six of 14 patients (43%) treated with omeprazole (5 of 8) or ranitidine (1 of 6) developed bacterial counts > 10(5) cfu/mL . All remained asymptomatic and had normal lactulose breath H2 profiles during treatment . CONCLUSION: Drug-induced hypochlorhydria causes high duodenal bacterial counts in the elderly but, in the short term, this bacterial overgrowth is not associated with malabsorption. Int J Pediatr Otorhinolaryngol, 1997 Dec 10, 42(2), 149 - 67 Audiovestibular and neuropsychological outcome of adults who had recovered from childhood bacterial meningitis; Hugosson S et al.; A sample of 22 subjects was studied from a population of adults who had suffered from bacterial meningitis in childhood . Audiovestibular, oculomotor and neuropsychological investigations were performed and quality of life was assessed . An age-matched control group of 20 subjects was recruited . In the meningitis group, nine subjects had abnormal pure tone audiograms . One was previously undiagnosed and a progression was found in four . There was an overrepresentation of subclinical vestibular pathology (6 out of 9 (67%)) in this group . Audiovestibular test results showed a peripheral pattern and oculomotor tests were normal . The quality of life scores of those with hearing loss were significantly higher than those in the control group . Neuropsychological tests of brain dysfunction were abnormal in six out of 22 (27%) who had recovered from meningitis . The prevalence of such dysfunctions was not related to audiovestibular disorder . The quality of life scores of those with brain dysfunctions were similar to those of the control group . The findings of reduced auditory memory and tone level perception in four out of 22 (18%), suggest that lesions of central auditory pathways may follow from bacterial meningitis . The results support the idea that inner ear damage is the major cause of hearing loss after bacterial meningitis . Despite the absence of brainstem involvement, central nervous system lesions with disturbed auditory processing and language functions can be of significance . The high frequency of discrete brain dysfunctions indicate that a thorough neuropsychological investigation is required after bacterial meningitis. Microb Comp Genomics, 1996, 1(3), 151 - 64 Novel phosphotransferase system genes revealed by bacterial genome analysis: the complete complement of pts genes in mycoplasma genitalium; Reizer J et al.; The complete sequence of the Mycoplasma genitalium chromosome has recently been determined . We here report analyses of the genes encoding proteins of the phosphoenolpyruvate:sugar phosphotransferase system, PTS . These genes encode (1) Enzyme I, (2) HPr, (3) a glucose-specific Enzyme IICBA, (4) an inactive glucose-specific Enzyme IIB, lacking the active site cysteyl residue, and (5) a fructose-specific Enzyme IIABC . Some of the unique features of these genes and their enzyme products are as follows . (1) Each of the genes is encoded within a distinct operon . (2) Both Enzyme I and HPr have basic isoelectric points . (3) The glucose-specific Enzyme IIC bears a centrally located, hydrophilic, 200 amino acyl residue insert that lacks sequence similarity with any protein in the current database . (4) The fructose-specific Enzyme II has a domain order (IIABC), different from those of previously characterized fructose permeases, and its IIA domain more closely resembles the IIANtr protein of Escherichia coli than other fructose-specific IIA domains . The potential significance of these novel features is discussed. FEBS Lett, 1998 Jul 3, 430(3), 363 - 9 Differential effects of bacterial lipopolysaccharides upon neutrophil function; Ruchaud-Sparagano MH et al.; Lipopolysaccharide (LPS) is a potent inflammatory agent which augments neutrophil sensitivity to subsequent inflammatory stimuli . In this study, the effects of structurally different LPS types upon neutrophil effector functions were examined . Rough LPS types, which have lost the O-polysaccharide moiety, were found to act more rapidly than smooth LPS types in stimulating neutrophil beta2 integrin activity and fMLP-induced respiratory burst . These findings suggest an involvement of the O-polysaccharide region of LPS in regulating neutrophil responsiveness to different LPS chemotypes with important implications for the mechanisms underlying regulation of the inflammatory response in conditions associated with elevation of LPS in plasma, e.g . septic shock or acute respiratory distress syndrome. EMBO J, 1998 Aug 3, 17(15), 4238 - 48 Response regulator output in bacterial chemotaxis; Alon U et al.; Chemotaxis responses in Escherichia coli are mediated by the phosphorylated response-regulator protein P-CheY . Biochemical and genetic studies have established the mechanisms by which the various components of the chemotaxis system, the membrane receptors and Che proteins function to modulate levels of CheY phosphorylation . Detailed models have been formulated to explain chemotaxis sensing in quantitative terms; however, the models cannot be adequately tested without knowledge of the quantitative relationship between P-CheY and bacterial swimming behavior . A computerized image analysis system was developed to collect extensive statistics on freeswimming and individual tethered cells . P-CheY levels were systematically varied by controlled expression of CheY in an E.coli strain lacking the CheY phosphatase, CheZ, and the receptor demethylating enzyme CheB . Tumbling frequency was found to vary with P-CheY concentration in a weakly sigmoidal fashion (apparent Hill coefficient approximately 2.5) . This indicates that the high sensitivity of the chemotaxis system is not derived from highly cooperative interactions between P-CheY and the flagellar motor, but rather depends on nonlinear effects within the chemotaxis signal transduction network . The complex relationship between single flagella rotation and free-swimming behavior was examined; our results indicate that there is an additional level of information processing associated with interactions between the individual flagella . An allosteric model of the motor switching process is proposed which gives a good fit to the observed switching induced by P-CheY . Thus the level of intracellular P-CheY can be estimated from behavior determinations: approximately 30% of the intracellular pool of CheY appears to be phosphorylated in fully adapted wild-type cells. Structure, 1998 Jul 15, 6(7), 809 - 13 Mind your B's and R's: bacterial chemotaxis, signal transduction and protein recognition; Jurica MS et al.; The crystal structures of two key regulators of the bacterial chemotaxis pathway (CheR and CheB) have been determined . These studies add further detail to the growing picture of signal transduction and attenuation in the bacterial chemotaxis pathway . The recently determined structure of the methyltransferase CheR bound to a peptide of its target receptor, provides a structural model for intermolecular receptor modification during signaling. Naturwissenschaften, 1998 Jun, 85(6), 253 - 61 Bacterial cytotoxins target Rho GTPases; Schmidt G et al.; Low molecular mass GTPases of the Rho family, which are involved in the regulation of the actin cytoskeleton and in various signal transduction processes, are the eukaryotic targets of bacterial protein toxins . The toxins covalently modify Rho proteins by ADP ribosylation, glucosylation, and deamidation, thereby inactivating and activating the GTPases. Braz J Med Biol Res, 1998 Jan, 31(1), 77 - 84 The role of T cell subsets and cytokines in the regulation of intracellular bacterial infection; Oliveira SC et al.; Cellular immune responses are a critical part of the host's defense against intracellular bacterial infections . Immunity to Brucella abortus crucially depends on antigen-specific T cell-mediated activation of macrophages, which are the major effectors of cell-mediated killing of this organism . T lymphocytes that proliferate in response to B . abortus were characterized for phenotype and cytokine activity . Human, murine, and bovine T lymphocytes exhibited a type 1 cytokine profile, suggesting an analogous immune response in these different hosts . In vivo protection afforded by a particular cell type is dependent on the antigen presented and the mechanism of antigen presentation . Studies using MHC class I and class II knockout mice infected with B . abortus have demonstrated that protective immunity to brucellosis is especially dependent on CD8+ T cells . To target MHC class I presentation we transfected ex vivo a murine macrophage cell line with B . abortus genes and adoptively transferred them to BALB/c mice . These transgenic macrophage clones induced partial protection in mice against experimental brucellosis . Knowing the cells required for protection, vaccines can be designed to activate the protective T cell subset . Lastly, as a new strategy for priming a specific class I-restricted T cell response in vivo, we used genetic immunization by particle bombardment-mediated gene transfer. Arq Neuropsiquiatr, 1998 Mar, 56(1), 83 - 7 {Etiology of bacterial meningitis in a cohort from Salvador, Bahia}; Nascimento-Carvalho CM et al.; Bacterial meningitis remains a very important disease world-wide, mainly during childhood . In order to describe the etiology of bacterial meningitis among some children in Salvador, Bahia-Brazil, we retrospectively reviewed 7000 cerebrospinal fluid exams, performed within the period of September 1988 up to August 1995, at the CSF Laboratory, Jose Silveira Foundation; 892(12.7%) exams met the inclusion criteria; patients less than 16 years of age and clinical meningitis diagnosis . Among 139 cases of bacterial meningitis, H . influenzae type b (Hib) was the most frequent cause (26.0%), all of the cases in children under 5 years . We have been questioning whether the declining Hib disease trend since 1992 has been associated with the use of Hib conjugate vaccines among those children. Am J Hum Genet, 1998 Aug, 63(2), 625 - 37 From amplification to gene in thyroid cancer: a high-resolution mapped bacterial-artificial-chromosome resource for cancer chromosome aberrations guides gene discovery after comparative genome hybridization; Chen X et al.; Chromosome rearrangements associated with neoplasms provide a rich resource for definition of the pathways of tumorigenesis . The power of comparative genome hybridization (CGH) to identify novel genes depends on the existence of suitable markers, which are lacking throughout most of the genome . We now report a general approach that translates CGH data into higher-resolution genomic-clone data that are then used to define the genes located in aneuploid regions . We used CGH to study 33 thyroid-tumor DNAs and two tumor-cell-line DNAs . The results revealed amplifications of chromosome band 2p21, with less-intense amplification on 2p13, 19q13.1, and 1p36 and with least-intense amplification on 1p34, 1q42, 5q31, 5q33-34, 9q32-34, and 14q32 . To define the 2p21 region amplified, a dense array of 373 FISH-mapped chromosome 2 bacterial artificial chromosomes (BACs) was constructed, and 87 of these were hybridized to a tumor-cell line . Four BACs carried genomic DNA that was amplified in these cells . The maximum amplified region was narrowed to 3-6 Mb by multicolor FISH with the flanking BACs, and the minimum amplicon size was defined by a contig of 420 kb . Sequence analysis of the amplified BAC 1D9 revealed a fragment of the gene, encoding protein kinase C epsilon (PKCepsilon), that was then shown to be amplified and rearranged in tumor cells . In summary, CGH combined with a dense mapped resource of BACs and large-scale sequencing has led directly to the definition of PKCepsilon as a previously unmapped candidate gene involved in thyroid tumorigenesis. Protein Sci, 1998 Jul, 7(7), 1647 - 52 Conserved sequence motifs among bacterial, eukaryotic, and archaeal phosphatases that define a new phosphohydrolase superfamily; Thaller MC et al.; Members of a new molecular family of bacterial nonspecific acid phosphatases (NSAPs), indicated as class C, were found to share significant sequence similarities to bacterial class B NSAPs and to some plant acid phosphatases, representing the first example of a family of bacterial NSAPs that has a relatively close eukaryotic counterpart . Despite the lack of an overall similarity, conserved sequence motifs were also identified among the above enzyme families (class B and class C bacterial NSAPs, and related plant phosphatases) and several other families of phosphohydrolases, including bacterial phosphoglycolate phosphatases, histidinol-phosphatase domains of the bacterial bifunctional enzymes imidazole-glycerolphosphate dehydratases, and bacterial, eukaryotic, and archaeal phosphoserine phosphatases and threalose-6-phosphatases . These conserved motifs are clustered within two domains, separated by a variable spacer region, according to the pattern {FILMAVT}-D-{ILFRMVY}-D-{GSNDE}-{TV}-{ILVAM}-{AT S VILMC}-X- inverted question markYFWHKR)-X- inverted question markYFWHNQ inverted question mark-X( 102,191)- inverted question markKRHNQ inverted question mark-G-D- inverted question markFYWHILVMC inverted question mark- inverted question markQNH inverted question mark- inverted question markFWYGP inverted question mark-D - inverted question markPSNQYW inverted question mark . The dephosphorylating activity common to all these proteins supports the definition of this phosphatase motif and the inclusion of these enzymes into a superfamily of phosphohydrolases that we propose to indicate as "DDDD" after the presence of the four invariant aspartate residues . Database searches retrieved various hypothetical proteins of unknown function containing this or similar motifs, for which a phosphohydrolase activity could be hypothesized. Drug Ther Bull, 1998 May, 36(5), 33 - 5 Management of bacterial vaginosis; Bacterial SOS checkpoint protein SulA inhibits polymerization of purified FtsZ cell division protein; Department of Enzymology, Merck Research Laboratories, Rahway, New Jersey 07065-0900, USACell division of Escherichia coli is inhibited when the SulA protein is induced in response to DNA damage as part of the SOS checkpoint control system . The SulA protein interacts with the tubulin-like FtsZ division protein . We investigated the effects of purified SulA upon FtsZ . SulA protein inhibits the polymerization and the GTPase activity of FtsZ, while point mutant SulA proteins show little effect on either of these FtsZ activities . SulA did not inhibit the polymerization of purified FtsZ2 mutant protein, which was originally isolated as insensitive to SulA . These studies define polymerization assays for FtsZ which respond to an authentic cellular regulator . The observations presented here support the notion that polymerization of FtsZ is central to its cellular role and that direct, reversible inhibition of FtsZ polymerization by SulA may account for division inhibition. J Bacteriol, 1998 Aug, 180(15), 3757 - 64 Computer-aided resolution of an experimental paradox in bacterial chemotaxis; Abouhamad WN et al.; Escherichia coli responds to its environment by means of a network of intracellular reactions which process signals from membrane-bound receptors and relay them to the flagellar motors . Although characterization of the reactions in the chemotaxis signaling pathway is sufficiently complete to construct computer simulations that predict the phenotypes of mutant strains with a high degree of accuracy, two previous experimental investigations of the activity remaining upon genetic deletion of multiple signaling components yielded several contradictory results (M . P . Conley, A . J . Wolfe, D . F . Blair, and H . C . Berg, J . Bacteriol . 171:5190-5193, 1989; J . D . Liu and J . S . Parkinson, Proc . Natl . Acad . Sci . USA 86:8703-8707, 1989) . For example, "building up" the pathway by adding back CheA and CheY to a gutted strain lacking chemotaxis genes resulted in counterclockwise flagellar rotation whereas "breaking down" the pathway by deleting chemotaxis genes except cheA and cheY resulted in alternating episodes of clockwise and counterclockwise flagellar rotation . Our computer simulation predicts that trace amounts of CheZ expressed in the gutted strain could account for this difference . We tested this explanation experimentally by constructing a mutant containing a new deletion of the che genes that cannot express CheZ and verified that the behavior of strains built up from the new deletion does in fact conform to both the phenotypes observed for breakdown strains and computer-generated predictions . Our findings consolidate the present view of the chemotaxis signaling pathway and highlight the utility of molecularly based computer models in the analysis of complex biochemical networks. Vaccine, 1998 May-Jun, 16(9-10), 1029 - 38 Are DNA-based vaccines useful for protection against secreted bacterial toxins? Tetanus toxin test case; Saikh KU et al.; Polypeptide and DNA vaccine alternatives to the conventional tetanus toxoid were compared . Mouse immunizations with plasmid DNA that encoded the tetanus toxin C fragment polypeptide induced consistently lower antibody responses than direct immunization with the C fragment polypeptide or toxoid, yet provided some degree of protection from a lethal toxin challenge . Cytotoxic T-cell responses dominated DNA immunizations, while specific T-cell proliferation resulted from all vaccines tested . Immune responses to the DNA vaccine exhibited a T-helper type-1 propensity, while polypeptides elicited T-helper type-2 responses . The lower antibody response to the plasmid vaccine was not due to insufficient quantity of C fragment in vivo but was likely the result of a mode of antigen presentation that was less efficient for supporting antibody production . Collectively, these results suggest that polypeptide or toxoid vaccines are preferable to plasmid-based vaccination for control of diseases caused by tetanus toxin. Mutat Res, 1998 Jul, 408(1), 47 - 54 Bacterial O6-methylguanine-DNA methyltransferase reduces N-methyl-N'-nitro-N-nitrosoguanidine induction of plasminogen activator in Mer- human glioblastoma A1235 cell line; Loncarek J et al.; The alkylation repair deficient (Mer- phenotype) cells produce high levels of proteolytic enzyme plasminogen activator (PA) after treatment with alkylation agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) . Both, in Escherichia coli and in mammalian cells O6-methylguanine (O6-MeG) is repaired by analogues O6-methylguanine-DNA methyltransferase (MGMT) . In E . coli MGMT is product of ada gene . To investigate the effect of bacterial MGMT expression on the induction of PA activity in human cells, we have transfected ada-alkB operon into Mer- human A1235 cells that are known to produce high levels of PA after MNNG treatment . We have shown here that A4 and A8 transformants that harbour ada gene become resistant to killing by MNNG . In addition, MNNG produced induction of extracellular PA activity was much less pronounced in A4 and A8 transformants (induction ratio 3.42 and 3.74, respectively) than in control A1235 and Aneo-1 cells (induction ratio 11.04 and 9.11, respectively) . However, changes of intracellular PA activity were not significant . It appears, therefore, that induction of extracellular PA activity is inversely related to the cell capacity to repair the DNA lesions induced by alkylation agents. Trends Microbiol, 1998 Jun, 6(6), 239 - 43 What happens to bacterial pathogens in vivo? Smith H. Most of our current knowledge about the molecular determinants of bacterial pathogenicity comes from studies with cultures in vitro . However, interest is increasing in bacterial behaviour in the complex and ever-changing environment of the infected host . New methods are revealing how bacteria behave in their hosts, providing many surprises and indicating how much of the subject remains unexplored. Trends Microbiol, 1998 Jun, 6(6), 222 - 8 Transcription and translation in Archaea: a mosaic of eukaryal and bacterial features; Bell SD et al.; The principal components involved in the processes of transcription and translation in Archaea have been identified by a combination of biochemistry and genome sequencing . In many cases, these factors are closely related to previously characterized proteins from Eukarya and Bacteria . Elucidating the function of these proteins will shed considerable light on the evolution of gene regulatory processes. Mutat Res, 1998 Jun 18, 402(1-2), 51 - 7 Detection of natural bioantimutagens and their mechanisms of action with bacterial assay-system; Simic D et al.; Escherichia coli K12 assay-system is designed in order to detect bioantimutagens, agents preventing mutagenesis by modulation of DNA repair and replication . The assay is composed of four tests aimed at the detection of inhibition of spontaneous and induced mutations (Tests A and B) and at the estimation whether the anti-mutagenic agent acts by increasing the fidelity of DNA replication (Test B), by inhibition of SOS error prone repair (Test C), or by favoring error-free recombinational repair (Test D) . In Test A, repair proficient strain and its uvrA counterpart are used for detection of spontaneous and UV-induced mutations, while in Test B mismatch repair deficient strains (mutH, mutS, mutL and uvrD) are used for amplified detection of spontaneous mutations caused by replication errors . In Test C, repair proficient strain carrying sfiA::lacZ fusion is used for measuring the level of SOS induction by monitoring the level of beta-galactosidase . In Test D, the strains carrying different recA alleles (recA+, recA730 and DeltarecA) are used for measuring intrachromosomal recombination between nonoverlapping deletions in duplicated lac operon, by monitoring Lac+ recombinants . The assay-system is validated with model bioantimutagens and used for detection of anti-mutagenic potential of different terpenoid fractions from sage (Salvia officinalis L.) . Extract E1/3 of cultivated sage, distinguished from others by its high content of monoterpenoid camphor, reduces UV-induced mutagenesis in Test A, while it has no effect in Tests B and C . In Test D, it enhances intrachromosomal recombination in untreated and UV-irradiated recA+ and recA730 strains . The results suggest that the protective effect is due to stimulation of recombinational repair, similarly to coumarin . We speculate that monoterpenoids from sage enhance genetic recombination by intervening in a formation of RecA-DNA complex and channeling it into recombination reaction . Protein Expr Purif, 1998 Jul, 13(2), 222 - 8 Bacterial expression and characterization of human recombinant apolipoprotein(a) kringle IV type 9; Chung FZ et al.; Elevated plasma lipoprotein(a) {Lp(a)} is an independent risk factor for several vascular diseases . Lp(a) particles are generated through the formation of a disulfide bond between Cys4057 of kringle IV type 9, (KIVt9), of the multikringle apolipoprotein(a) {apo(a)} and a cysteine in apoB-100 low-density lipoprotein (LDL) . To better understand this interaction, we have expressed and purified KIVt9 from Escherichia coli as a His-Tag fusionprotein . Dithiothreitol (DTT)-treated purified KIVt9 migrated as a single approximately 17 . 3-kDa band on SDS-PAGE gels . Without DTT, an additional band twice the molecular weight of KIVt9 was observed . The double-size band presumably resulted from dimerization of individual kringles, through their unpaired cysteine residues, since a mutation Cys4057 --> Ser ({Ser4057}KIVt9) abolished dimer formation . Using a gel-shift assay, we showed that KIVt9 could couple to 14-amino-acid apoB-100 synthetic peptides (apoB3732-3745 and apoB4319-4332) containing Cys3734 or Cys4326 . Both of these apoB-100 cysteines have been reported to associate with apo(a) to generate Lp(a) . In the presence of either apoB-100 peptide, KIVt9 was shifted to a higher molecular weight that was consistent with the covalent addition of a 1.2-kDa apoB-100 peptide . Identical apoB-100 peptides in which the cysteine residues were replaced by alanine ({Ala3734}apoB3732-3745 and {Ala4326}apoB4319-4332) had no effect in the gel-shift assay . Furthermore, {Ser4057}KIVt9 did not covalently interact with apoB3732-3745 or apoB4319-4332 . These results indicated that KIVt9 couples to the Cys-apoB-100 peptides through a disulfide linkage . This system may be suitable for further investigating the apo(a)/apoB-100 coupling reaction and the structure of KIVt9 through X-ray crystallographic studies . Can J Microbiol, 1998 Apr, 44(4), 351 - 5 Bacterial fitness and plasmid loss: the importance of culture conditions and plasmid size; Smith MA et al.; Several pBluescript-derived plasmids of various sizes were constructed to study the effects of multicopy plasmid size on bacterial fitness and plasmid loss . Transformed and untransformed bacterial clones were grown in media with or without ampicillin . Bacterial fitness (measured by growth rate), plasmid presence or absence, and plasmid copy number were assessed during successive subculturings . In selective media (minimal medium or Luria Broth plus ampicillin), the clone transformed with the largest plasmid (pBluescript with a 9000-bp insert) had a significantly longer lag phase than all other clones . In nonselective media the rate of plasmid loss during successive subculturings was greatest in the clone with the largest insert . The clone with the largest insert displayed a lower plasmid copy number than clones with a small insert or no insert at all . Plasmid loss in the form of segregational instability and plasmid copy number reduction in nonselective environments are important to the understanding of the evolution of the bacteria-plasmid associations and the appreciation of the potential for altering the genetic properties of a clone maintained or subcultured on a standard medium. Arch Latinoam Nutr, 1997 Sep, 47(3), 229 - 33 {Bread staling . Simultaneous effect of bacterial alpha-amylase and emulsifier on firmness and pasting properties of bread crumbs++}; Grossmann MV et al.; The effect of bacterial alpha-amylase and an emulsifier on firmness and amylograph characteristics of bread crumb during storage was studied . The bread which contained these additives was less firm and stalled more slowly than the control . The enzyme and the emulsifier retarded firmness but the emulsifier inhibited the action of the alpha-amylase . The regulatory action of the emulsifier also was observed on amylograph characteristics of bread crumb (peak viscosity, cool viscosity and setback). Am J Gastroenterol, 1998 Jul, 93(7), 1073 - 9 Influence of bacterial CagA status on gastritis, gastric function indices, and pattern of symptoms in H . pylori-positive dyspeptic patients; Parente F et al.; OBJECTIVE: To date, little is known about a possible relationship between H . pylori-related disturbances of gastric function and the bacterial virulence . The aim of this study was to assess whether certain gastric function indices as well as the pattern of symptoms in nonulcer dyspepsia (NUD) are related to CagA status . METHODS: A total of 56 consecutive patients with NUD (38 H . pylori-positive and 18 H . pylori-negative) were studied . Dyspeptic symptoms were categorized according to the predominant complaints and scored for severity and frequency . In all subjects, basal and pentagastrin-stimulated acid secretion, fasting and meal-induced gastrin release, fasting serum pepsinogen I (PG I) levels, and gastric emptying of solids were determined . CagA status was determined by assaying serum CagA IgG antibodies by western blotting . RESULTS: Eighteen of 38 (47%) H . pylori-positive dyspeptics were CagA seropositive . Type and severity of dyspeptic symptoms did not significantly differ between CagA-positive and CagA-negative dyspeptics nor between H . pylori-positive and negative patients . Among the gastric function indices studied, only meal-stimulated gastrin was significantly influenced by CagA status (peak gastrin 129.9 {44.1} vs 99.1 {48.6} pg/ml in CagA-positive and negative NUD, respectively), but this was not accompanied by any significant modification of basal or stimulated acid secretion or gastric emptying of solids . The activities of both antral and corpus gastritis in NUD harboring CagA-positive strains were significantly higher than those of CagA-negative NUD . Accordingly, serum PG I levels were significantly higher in CagA-positive than CagA-negative or H . pylori-negative dyspeptics . CONCLUSIONS: These findings support a role for CagA status in influencing the activity and perhaps the distribution of gastritis in NUD, as well as the degree of gastrin response to a meal; however, this is not accompanied by disturbances of acid secretion or gastric emptying or by differences in the type and severity of symptoms. J Mol Biol, 1998 Jul 31, 280(5), 821 - 8 Fumarate modulates bacterial flagellar rotation by lowering the free energy difference between the clockwise and counterclockwise states of the motor; Prasad K et al.; Switching flagellar rotation from one direction to another is an essential part of bacterial chemotaxis . Fumarate has been shown to possess the capacity to restore to flagella of cytoplasm-free, CheY-containing bacterial envelopes the ability to switch directions and to increase the probability of reversal in intact cells . Neither the target of fumarate action nor the mechanism of function is known . To distinguish between the two potential targets of fumarate, the response regulator CheY and the flagellar switch-motor complex, we compared flagellar rotation between isogenic strains that lacked CheY and had either low or high levels of fumarate . The difference in the fumarate levels was due to a deletion of the genes encoding the enzymes that synthesize and metabolize fumarate; succinate dehydrogenase and fumarase, respectively . The strains were in a gutted background (i.e . a background deleted for the cytoplasmic chemotaxis proteins and some of the receptors), and switching was achieved by carrying out the measurements at 2.5 degreesC, where it has been demonstrated that gutted cells switch spontaneously . The flagellar rotation of the strain with the highest level of fumarate was the most clockwise-biased and had the highest reversal frequency, indicating that fumarate is effective even in the absence of CheY . Fumarate reduced the free energy difference of the counterclockwise-to-clockwise transition and had no appreciable effect on the activation energy of this transition . Similar observations were made at room temperature, provided that intracellular CheY was present . In a wild-type background, both mutants made rings on semi-solid agar typical of normal chemotaxis . Taken together, the results suggest that the target of fumarate is the switch-motor complex, that fumarate acts by increasing the probability of the clockwise state, and that a fumarate level as low as that found in succinate dehydrogenase mutants is sufficient for normal chemotaxis . EMBO J, 1998 Jul 15, 17(14), 3827 - 37 Chimeric purine transporters of Aspergillus nidulans define a domain critical for function and specificity conserved in bacterial, plant and metazoan homologues; Diallinas G et al.; In Aspergillus nidulans, purine uptake is mediated by three transporter proteins: UapA, UapC and AzgA . UapA and UapC have partially overlapping functions, are 62% identical and have nearly identical predicted topologies . Their structural similarity is associated with overlapping substrate specificities; UapA is a high-affinity, high-capacity specific xanthine/uric acid transporter . UapC is a low/moderate-capacity general purine transporter . We constructed and characterized UapA/UapC, UapC/UapA and UapA/UapC/UapA chimeric proteins and UapA point mutations . The region including residues 378-446 in UapA (336-404 in UapC) has been shown to be critical for purine recognition and transport . Within this region, we identified: (i) one amino acid residue (A404) important for transporter function but probably not for specificity and two residues (E412 and R414) important for UapA function and specificity; and (ii) a sequence, (F/Y/S)X(Q/E/P) NXGXXXXT(K/R/G), which is highly conserved in all homologues of nucleobase transporters from bacteria to man . The UapC/UapA series of chimeras behaves in a linear pattern and leads to an univocal assignment of functional domains while the analysis of the reciprocal and 'sandwich' chimeras revealed unexpected inter-domain interactions . cDNAs coding for transporters including the specificity region defined by these studies have been identified for the first time in the human and Caenorhabditis elegans databases. Br J Surg, 1998 Jun, 85(6), 785 - 9 Lower limb ischaemia-reperfusion injury causes endotoxaemia and endogenous antiendotoxin antibody consumption but not bacterial translocation; Yassin MM et al.; BACKGROUND: It has been suggested that reperfusion of the acutely ischaemic lower limb alters gut permeability . The effect of lower limb ischaemia-reperfusion on systemic endotoxin and antiendotoxin antibody concentrations and the incidence of bacterial translocation was investigated . METHODS: Systemic endotoxin and antiendotoxin antibody concentrations were measured in five groups of male Wistar rats: control, after 3 h of bilateral hind limb ischaemia alone, and after 3 h of bilateral hind limb ischaemia followed by 1, 2 or 3 h of reperfusion . A second experiment examined translocation of indigenous bacteria following 2 h of reperfusion in a similar model . RESULTS: Ischaemia followed by reperfusion for 1, 2 or 3 h caused a significant increase in plasma endotoxin concentration to mean(s.e.m.) 10.0(3.0), 44.8(19.2) and 20.2(6.2) pg/ml compared with that in control animals (2.58(0.91) pg/ml) or animals in the ischaemia alone group (1.2(0.9) pg/ml) (P < 0.05) . This was associated with a significant reduction in endogenous antiendotoxin antibody (immunoglobulin (Ig) G and IgM) concentration . No significant bacterial translocation was detected in any of the groups studied . CONCLUSION: These results demonstrate that a remote and isolated ischaemia-reperfusion injury to the lower limb, in the absence of infection or bacterial translocation, causes endotoxaemia . Further studies are needed to evaluate the role of endogenous antiendotoxin antibodies in this situation. Mikrobiologiia, 1998 Mar-Apr, 67(2), 281 - 6 {Old problems of new bacterial systematics}; Golovlev EL; This review analyzes the situation that arose after the existence of adaptive mutations had been proven . Manifold acceleration of the mutation process and intragenome rearrangements in nondividing cells demonstrates the inapplicability of the theory of neutral evolution to bacteria, the lack of isochronism between the evolution of individual macromolecules and the organism as a whole, and thus, the invalidity of using rRNA homologies as markers of the position of the organism in the phylogenetic tree and in the taxonomic system. Vet Immunol Immunopathol, 1998 Jul 8, 64(2), 161 - 72 Evaluation of various cytokines (IL-6, IFN-alpha, IFN-gamma, TNF-alpha) as markers for acute bacterial infection in swine--a possible role for serum interleukin-6; Fossum C et al.; A total of 64 specific pathogen free pigs were divided into eight experimental groups . Pigs in Group I served as non-infected controls while the other 56 pigs were infected intranasally with approximately 7 x 10(8) CFU of Actinobacillus pleuropneumoniae serotype 2 (strain 700/89) in 1 ml saline . When more than 25% of the infected animals showed clinical signs of disease, i.e . 20 h post infection, 48 of the infected pigs were treated with different antibiotics (8 pigs per group), leaving 8 infected animals untreated . Serum samples collected 0, 10, 20, 28 and 44 h, and 3, 4, 7, 13 and 17 days post infection were analysed for their content of interferon (IFN)-alpha, IFN-gamma, tumor necrosis factor (TNF)-alpha by immunoassays and interleukin-6 (IL-6) by a bioassay . In addition, the development of specific antibodies was determined in sera . Among the cytokines analysed, the experimental infection only induced detectable serum levels of IL-6 . The appearance of IL-6 positive animals coincided with the onset of clinical signs of disease and increased body temperatures . Varying levels of IL-6 (range, 1-220 U ml-1) were detected in serum from a majority of the infected pigs (80%) . In general, the highest levels of IL-6 were detected in serum collected for 10 or 20 h after infection . Among the animals not treated with antibiotics, the number of pigs displaying IL-6 in serum continued to increase until 28 h post infection and then declined . The duration of the IL-6 response varied between individuals and lasted from eight hours to three days . Treatment with antibiotics that ceased the infection also terminated the IL-6 production in most of the pigs . In a pilot field survey, IL-6 was detected in an approximately 30% of serum samples collected from conventional reared pigs before allocation to finishing units . Thus, serum IL-6 seems to be a potential marker for ongoing bacterial infections in swine. J Biol Chem, 1998 Jul 17, 273(29), 18003 - 6 An essential component of a novel bacterial protein export system with homologues in plastids and mitochondria; Bogsch EG et al.; Proteins are transported across the bacterial plasma membrane and the chloroplast thylakoid membrane by means of protein translocases that recognize N-terminal targeting signals in their cognate substrates . Transport of many of these proteins involves the well defined Sec apparatus that operates in both membranes . We describe here the identification of a novel component of a bacterial Sec-independent translocase . The system probably functions in a similar manner to a Sec-independent translocase in the thylakoid membrane, and substrates for both systems bear a characteristic twin-arginine motif in the targeting peptide . The translocase component is encoded in Escherichia coli by an unassigned reading frame, yigU, disruption of which blocks the export of at least five twin-Arg-containing precursor proteins that are predicted to bind redox cofactors, and hence fold, prior to translocation . The Sec pathway remains unaffected in the deletion strain . The gene has been designated tatC (for twin-arginine translocation), and we show that homologous genes are present in a range of bacteria, plastids, and mitochondria . These findings suggest a central role for TatC-type proteins in the translocation of tightly folded proteins across a spectrum of biological membranes. Eur J Biochem, 1998 Jun 1, 254(2), 433 - 8 Identification of peptides inhibiting enzyme I of the bacterial phosphotransferase system using combinatorial cellulose-bound peptide libraries; Mukhija S et al.; The phosphoenolpyruvate(P-pyruvate)-dependent sugar phosphotransferase system (PTS) is a transport and signal-transduction system which is almost ubiquitous in bacteria but does not occur in eucaryotes . It catalyzes the uptake and phosphorylation of carbohydrates and is involved in signal transduction, e.g . catabolite repression, chemotaxis, and allosteric regulation of metabolic enzymes and transporters . EI (Enzyme I of the PTS) is the first and central component of the divergent PTS (P-pyruvate-dependent sugar phosphotransferase system) phosphorylation cascade . Using immobilized combinatorial peptide libraries and phosphorimaging, heptapeptides and octapeptides were identified which selectively inhibit EI in vitro . The IC50 of the best peptides is 30 microM which is close to the K(M) (6 microM) of EI for its natural substrate HPr (histidine containing phosphoryl carrier protein of the PTS) . The affinity-selected peptides are better inhibitors than a peptide with the active-site sequence of HPr . The selected peptides contain several basic residues and one aromatic residue which do not occur in the active site of HPr . The large proportion of basic residues most likely reflects charge complementarity to the strongly acidic active-site pocket of EI . Guanidino groups might facilitate by complexation of the phosphoryl group the slow phosphorylation of the peptide. Orv Hetil, 1998 Jun 7, 139(23), 1403 - 8 {Bacterial vaginosis}; Gardo S; Bacterial vaginosis being the most frequent vaginal infection is the leading cause of genital fluor . The author reviews the latest developments regarding the etiology, diagnostics and therapy of disease . Per os metronidazol and intravaginal clindamycin play the main role in treatment . The most often occurring complications of bacterial vaginosis are premature rupture of membrane and premature labour, postpartum endometritis, pelvic inflammatory disease and gynecological postoperative infections. Acta Oncol, 1998, 37(2), 179 - 85 Growth hormone reduces mortality and bacterial translocation in irradiated rats; Gomez-de-Segura IA et al.; Growth hormone stimulates the growth of intestinal mucosa and may reduce the severity of injury caused by radiation . Male Wistar rats underwent abdominal irradiation (12 Gy) and were treated with either human growth hormone (hGH) or saline, and sacrificed at day 4 or 7 post-irradiation . Bacterial translocation, and the ileal mucosal thickness, proliferation, and disaccharidase activity were assessed . Mortality was 65% in irradiated animals, whereas hGH caused a decrement (29%, p < 0.05) . Bacterial translocation was also reduced by hGH (p < 0.05) . Treating irradiated rats with hGH prevented body weight loss (p < 0.05) . Mucosal thickness increased faster in irradiated hGH-treated animals . The proliferative index showed an increment in hGH-treated animals (p < 0.05) . Giving hGH to irradiated rats prevented decrease in sucrose activity, and increment in lactase activity . In conclusion, giving hGH to irradiated rats promotes the adaptative process of the intestine and acute radiation-related negative effects, including mortality, bacterial translocation, and weight loss. Science, 1998 Jul 10, 281(5374), 231 - 4 Major bacterial contribution to marine dissolved organic nitrogen McCarthy MD, Hedges JI, Benner R. Next to N2 gas, the largest pool of reduced nitrogen in the ocean resides in the enormous reservoir of dissolved organic nitrogen (DON) . The chemical identity of most of this material, and the mechanisms by which it is cycled, remain fundamental questions in contemporary oceanography . Amino acid enantiomeric ratios in the high molecular weight fraction of DON from surface and deep water in three ocean basins show substantial enrichment in D enantiomers of four amino acids . The magnitude and pattern of these D/L enrichments indicate that peptidoglycan remnants derived from bacterial cell walls constitute a major source of DON throughout the sea . These observations suggest that structural properties of specific bacterial biopolymers, and the mechanisms for their accumulation, are among the central controls on long-term cycling of dissolved organic nitrogen in the sea. Hepatology, 1998 Jul, 28(1), 17 - 21 The diagnostic and predictive value of ascites nitric oxide levels in patients with spontaneous bacterial peritonitis; Garcia-Tsao G et al.; Nitric oxide (NO) is a messenger molecule involved in pathogen suppression . Cirrhosis is characterized by an increased risk for infections, including spontaneous bacterial peritonitis (SBP) . The role of NO in the infections that develop in cirrhosis has not been clearly established . The aim of this study was to investigate the utility of measuring ascites NO in the diagnosis of SBP and/or in determining the predisposition of cirrhotic patients to develop this infection . Nitric oxide metabolites (nitrites + nitrates {NOx}) were measured by chemiluminescence in 105 ascites samples obtained from 87 cirrhotic patients and in 87 simultaneously obtained serum samples . Ascites NO levels were not significantly different among ascites from patients with SBP (n = 39; median, 48 micromol/L), patients with sterile ascites (n = 54; median, 42 micromol/L), and samples obtained after patients with SBP had been treated (n = 12; median, 62 micromol/L) . No differences in ascites NO levels were observed between culture-positive and culture-negative peritonitis . Among 50 patients with sterile ascites on initial paracentesis, 7 patients developed peritonitis during follow-up; no differences in baseline NO levels were observed between patients who developed peritonitis (median, 46 micromol/L) and those who did not (median, 41 micromol/L) . Among patients with SBP, mortality was significantly higher in those with NO levels >60 micromol/L . A very significant direct correlation was found between ascites and serum NO levels (r2 = .86) . In conclusion, ascites NO levels in cirrhotic patients are not useful either to diagnose or to determine predisposition to SBP . Rather, ascites NO levels reflect serum levels, are higher in cirrhotic patients with more severe liver disease, and may be a useful prognostic marker. Rev Esp Enferm Dig, 1998 May, 90(5), 353 - 60 Growth hormone reduces bacterial translocation in radiation enteritis in the rat; Prieto I et al.; BACKGROUND: Radiotherapy may be considered as one of the most effective treatments for digestive tumours . This procedure has major side effects, especially in fast growing tissues like intestinal mucosa . The administration of drugs that reduce or avoid radiation injury of the intestinal mucosa may be clinically advantageous . Growth hormone is a peptide suitable for this purpose by modifying cell proliferation within the intestinal crypt . MATERIAL AND METHOD: Adult male Wistar rats were used in a model of abdominal irradiation . Each irradiated animal received 1200 cGy under anaesthesia and was sacrificed four and seven days later . The animals were treated with either saline or growth hormone (1 mg/kg/day) beginning immediately after the irradiation treatment . On the day of sacrifice, intestinal samples were taken for morphometric measurements and mesenteric lymph nodes for bacterial translocation . RESULTS: Mortality was of 50% approximately and was not affected by growth hormone treatment in irradiated animals . Bacterial translocation increased (p < 0.05) in irradiated animals whereas no significant increase was observed in rats treated with growth hormone . Growth hormone promotes an earlier growth of intestinal villi in irradiated animals (p < 0.05) . CONCLUSIONS: Growth hormone promotes the morphologic adaptation of intestinal mucosa after abdominal irradiation, reducing bacterial translocation in rat. Immunity, 1998 Jun, 8(6), 771 - 7 Innate immune recognition of bacterial lipopolysaccharide: dependence on interactions with membrane lipids and endocytic movement; Thieblemont N et al.; Lipopolysaccharide ({LPS}, an endotoxin) from most bacterial species provokes a strong inflammatory response in naive animals . LPS from Rhodobacter sphaeroides (RsLPS) has a relatively small hydrophobic region and does not stimulate cells or animals but instead acts as antagonist of LPS action . Here, we show that the activity of RsLPS is transformed from antagonist to full agonist by the addition of chlorpromazine (CPZ) and other cationic membrane-active agents . In addition, while LPS is rapidly transported from the plasma membrane to an intracellular site, we find that RsLPS is not transported but instead remains in the cell periphery . Addition of CPZ also reverses this behavior, causing RsLPS to be transported to a perinuclear site . The data suggest that the interaction of LPS with membrane lipids is influenced by membrane-modifying agents such as CPZ, and these interactions dictate both its intracellular transport and its ability to stimulate cellular responses. Environ Mol Mutagen, 1998, 31(4), 402 - 8 Mutagenicity and clastogenicity of gas stove emissions in bacterial and plant tests; Monarca S et al.; The aim of this research was to study the gaseous and particulate emissions of genotoxic substances during cooking with two types of methane stoves (a new one and an old one) . The particulates were sampled both with a cascade impactor air sampler and an impinger with ice trap and analyzed by two bacterial mutagenicity tests (Ames and Kado tests) and by HPLC for polycyclic aromatic hydrocarbons (PAH) . Gaseous emissions were studied in situ using the Ames test, a clastogenicity plant test (Tradescantia-micronucleus test), and in an automated system for chemical analyses . Clear indirect mutagenicity was found only with the Kado test (TA98-S9) in extracts of particulates emitted from the old methane stove and collected with the impinger . Similar mutagenicity (TA98+S9) was also found for the finest fraction of particulates (<0.5 um) collected from both stoves . Gaseous emissions of both stoves caused clastogenicity in the in situ experiments with the Tradescantia-micronucleus test . The physico-chemical analyses of the emissions showed also the presence of very fine particulates and trace amounts of PAH . The exposure of these genotoxins could be particularly important for occupationally exposed individuals in homes and businesses and for susceptible subjects living indoors for long periods (infants, children, the sick, and the elderly). Curr Biol, 1998 Jun 18, 8(13), R444 - 6 Bacterial chemotaxis: unsolved mystery of the flagellar switch; Eisenbach M et al.; Impressive progress has been made in understanding the mechanism of bacterial chemotaxis and function of the flagellar motor, but how the direction of rotation is reversed by the 'flagellar switch'--a central step in chemotaxis--remains obscure and calls for new experimental approaches. Mol Plant Microbe Interact, 1998 Jul, 11(7), 659 - 67 Genetic characterization of RRS1, a recessive locus in Arabidopsis thaliana that confers resistance to the bacterial soilborne pathogen Ralstonia solanacearum; Deslandes L et al.; The soilborne, vascular pathogen Ralstonia solanacearum, the causative agent of bacterial wilt, was shown to infect a range of Arabidopsis thaliana accessions . The pathogen was capable of infecting the Col-5 accession in an hrp-dependent manner, following root inoculation . Elevated bacterial population levels were found in leaves of Col-5, 4 to 5 days after root inoculation by the GMI1000 strain . Bacteria were found predominantly in the xylem vessels and spread systematically throughout the plant . The Nd-1 accession of A . thaliana was resistant to the GMI1000 strain of R . solanacearum . Bacterial concentrations detected in leaves of Nd-1, inoculated with an hrp+ strain of R . solanacearum, were only slightly higher than those detected in the susceptible accession, Col-5, following inoculation with a strain whose hrp gene cluster was deleted . Leaf inoculation of the GMI1000 strain on the resistant accession Nd-1 induced the formation of lesions in the older leaves of the rosette whereas the same strain of R . solanacearum provoked complete wilting of Col-5 . Resistance to strain GMI1000 of R . solanacearum segregated as a simply inherited recessive trait in a genetic cross between Col-5 and Nd-1 . F9 recombinant inbred lines generated between these two accessions were used to map a locus, RRS1, that was the major determinant of resistance between restriction fragment length polymorphism markers mi83 and mi61 on chromosome V . This region of the A . thaliana genome is known to contain many other pathogen recognition capabilities. EMBO J, 1998 Jul 1, 17(13), 3640 - 50 Overlapping functions of components of a bacterial Sec-independent protein export pathway; Sargent F et al.; We describe the identification of two Escherichia coli genes required for the export of cofactor-containing periplasmic proteins, synthesized with signal peptides containing a twin arginine motif . Both gene products are homologous to the maize HCF106 protein required for the translocation of a subset of lumenal proteins across the thylakoid membrane . Disruption of either gene affects the export of a range of such proteins, and a complete block is observed when both genes are inactivated . The Sec protein export pathway was unaffected, indicating the involvement of the gene products in a novel export system . The accumulation of active cofactor-containing proteins in the cytoplasm of the mutant strains suggests a role for the gene products in the translocation of folded proteins . One of the two HCF106 homologues is encoded by the first gene of a four cistron operon, tatABCD, and the second by an unlinked gene, tatE . A mutation previously assigned to the hcf106 homologue encoded at the tatABCD locus, mttA, lies instead in the tatB gene. Biochemistry, 1998 Jun 30, 37(26), 9316 - 22 NMR solution structure of the oxidized form of MerP, a mercuric ion binding protein involved in bacterial mercuric ion resistance; Qian H et al.; Mercuric ions are toxic to living organisms because of their strong affinity for cysteine residues in proteins . Some bacteria have developed a resistance mechanism whereby Hg2+ is transported into the cytoplasm and reduced to Hg0 . One of the proteins involved in the transport of mercuric ion is the periplasmic binding protein MerP, which can exist both as oxidized (disulfide) and as reduced (dithiol) forms . Only the reduced form with Cys-17 and Cys-14 residues as free thiols is a potent receptor for mercuric ion . In this work the solution structure of the oxidized form of MerP has been determined by multidimensional NMR spectroscopy and compared to the NMR structures of the previously published structures of the reduced and mercury-bound forms of MerP . The mercury-bound and oxidized forms have similar tertiary structures, whereas in the reduced form there is a large rearrangement of the mercuric ion binding loop and the nearby loop comprising residues 38-41 . The structural arrangement of the latter loop seems to be important for the stabilization of the surface location of the cysteine-containing loop . In the reduced form at low pH the cysteine-containing loop adopts a conformation similar to what is observed in the oxidized and mercury-bound forms . The oxidized form also differs with respect to the other two forms in the relative positions of some of the alpha-helices and beta-strands . Structural differences between the oxidized and reduced forms may help explain why the reduced form is stable in the periplasm, which is considered to be an oxidizing environment. Bull World Health Organ, 1998, 76(2), 173 - 81 Bacterial contamination of the lacteal contents of feeding bottles in metropolitan São Paulo, Brazil; Morais TB et al.; Reported are the results of a study in Sao Paulo, Brazil, to evaluate the bacterial contamination of the lacteal contents of feeding bottles prepared in urban households of low (LSE) and high (HSE) socioeconomic groups, involving 100 and 32 mothers of infants, respectively . Samples of the lacteal contents of the feeding bottles were cultured and the medians (25th and 75th percentiles) of the counts (bacteria per ml) were significantly higher in the LSE group: mesophilic bacteria, 555,000 (17,250-4,350,000) in the LSE group and 1615 (20-500,000) in the HSE group; coliforms, 2400 (19-150,000) in the LSE group and 7 (0-7800) in the HSE group . Escherichia coli was isolated from 26% (26/100) of the samples from the LSE group and from 6% (2/32) of those from the HSE group (P = 0.03) . In the HSE group, higher coliform counts were associated with foodhandlers other than the mother, lower levels of maternal education, the use of pasteurized milk, and the addition of ingredients other than milk . In the LSE group, feeding bottles prepared using tap water and those prepared for infants aged over 6 months had higher coliform counts . In general, the feeding bottles prepared in the households studied were heavily contaminated, especially in the LSE group. Appl Environ Microbiol, 1998 Jul, 64(7), 2624 - 9 Cloning of Phanerochaete chrysosporium leu2 by complementation of bacterial auxotrophs and transformation of fungal auxotrophs; Zapanta LS et al.; A Phanerochaete chrysosporium cDNA library was constructed in an expression vector that allows expression in both Escherichia coli and Saccharomyces cerevisiae . This expression vector, lambda YES, contains the lacZ promoter for expression in E . coli and the GAL1 promoter for expression in yeast . A number of genes were cloned by complementation of bacterial amino acid auxotrophs . The cDNA encoding the beta-isopropylmalate dehydrogenase from P . chrysosporium was characterized further . The genomic clone (gleu2) was subsequently isolated and was used successfully as a selectable marker to transform P . chrysosporium auxotrophs for LEU2 . Protoplasts for transformation were prepared with readily obtained conidiospores rather than with basidiospores, which were used in previous P . chrysosporium transformation procedures . The method described here allows other genes to be isolated from P . chrysosporium for use as selectable markers. Clin Immunol Immunopathol, 1998 Jun, 87(3), 304 - 8 Human neutrophils express the prostaglandin G/H synthase 2 gene when stimulated with bacterial lipopolysaccharide; Fasano MB et al.; Human blood neutrophils (PMN) rapidly release arachidonic acid (AA) from cellular phospholipids when stimulated in vitro with a variety of inflammatory agonists . Free AA is then metabolized via 5'-lipoxygenase to produce bioactive mediators such as leukotriene B4 and 5-hydroxyeicosatetraenoate . Arachidonic acid can also be metabolized via the cyclooxygenase or prostaglandin G/H synthase (PGHS) pathway to form prostaglandins and thromboxane . We show here that human blood PMN express the PGHS 2 gene when stimulated with bacterial lipopolysaccharide (LPS) . PGHS 2 mRNA increases within 30 min after LPS stimulation and PGHS 2 immunoreactive protein is detectable by 5 h . Although PGHS 1 mRNA is detectable in PMN, no immunoreactive protein is observed in either resting or LPS-stimulated cells . Following stimulation with LPS and expression of PGHS 2, PMN increase secretion of prostaglandin E2 . This phenotypic change in PMN could be an important mechanism for regulating inflammation. FEBS Lett, 1998 May 22, 428(1-2), 47 - 51 Inhibition of ascorbate peroxidase under oxidative stress in tobacco having bacterial catalase in chloroplasts; Shikanai T et al.; To analyze the potential of the active oxygen-scavenging system of chloroplasts, we introduced Escherichia coli catalase into tobacco chloroplasts . Photosynthesis of transgenic plants was tolerant to high irradiance under drought conditions, while the wild plants suffered severe damage in photosynthesis under the same conditions . Irrespective of responses to the stress, ascorbate peroxidase was completely inactivated both in the transgenic and wild-type plants . These findings are contrary to the established idea that the ascorbate peroxidase-mediated antioxidative system protects chloroplasts from oxidative stress. Izv Akad Nauk Ser Biol, 1998 May-Jun, (3), 351 - 5 {Flocculation of bacterial cells in culture with protozoa}; Gurevich IuL et al.; The initial phase of formation of the biogenic suspension was studied in experimental communities of bacteria and protozoans that simulate degradation of the phenol technogenic flows . Protozoans were shown to initiate formation of bacterial aggregates and increase the size of bacterial flocules several hundred times . Factors were found by the methods of mathematical planning, which markedly affect the size and amount of flocules . Unlike natural water bodies, in the sample communities, the presence of abiogenic substrate was not essential for aggregation of the bacteria . The aggregated bacterial cells make an important contribution to degradation of organic compounds. J Bacteriol, 1998 Jul, 180(13), 3375 - 80 Regulation of switching frequency and bias of the bacterial flagellar motor by CheY and fumarate; Montrone M et al.; The effect of CheY and fumarate on switching frequency and rotational bias of the bacterial flagellar motor was analyzed by computer-aided tracking of tethered Escherichia coli . Plots of cells overexpressing CheY in a gutted background showed a bell-shaped correlation curve of Switching frequency and bias centering at about 50% clockwise rotation . Gutted cells (i.e., with cheA to cheZ deleted) with a low CheY level but a high cytoplasmic fumarate concentration displayed the same correlation of switching frequency and bias as cells overexpressing CheY at the wild-type fumarate level . Hence, a high fumarate level can phenotypically mimic CheY overexpression by simultaneously changing the switching frequency and the bias . A linear correlation of cytoplasmic fumarate concentration and clockwise rotation bias was found and predicts exclusively counter-clockwise rotation without switching when fumarate is absent . This suggests that (i) fumarate is essential for clockwise rotation in vivo and (ii) any metabolically induced fluctuation of its cytoplasmic concentration will result in a transient change in bias and switching probability . A high fumarate level resulted in a dose-response curve linking bias and cytoplasmic CheY concentration that was offset but with a slope similar to that for a low fumarate level . It is concluded that fumarate and CheY act additively presumably at different reaction steps in the conformational transition of the switch complex from counterclockwise to clockwise motor rotation. Biol Signals Recept, 1998 Jan-Feb, 7(1), 7 - 14 Hypothalamic relationships between interleukin-6 and LHRH release affected by bacterial endotoxin in adult male rats . Involvement of the inhibitory amino acid system; Feleder C et al.; Immune system alterations coexist with modifications in the reproductive axis . The bacterial endotoxin lipopolysaccharide (LPS) has inflammatory effects and stimulates cytokine release in the hypothalamus where LHRH neurons are located . LPS inhibition of LHRH release at hypothalamic level appears to be associated with modifications in the cerebral immune system . Central and peripheral LPS administration induces the expression and release of several cytokines in the central nervous system . Hence the present study was designed to investigate a possible function of the interleukin-6 (IL-6) stimulated by LPS in the regulation of LHRH secretion . Male rats were decapitated, and the preoptic mediobasal hypothalamic area (PO/MBH) was dissected and superfused with Earle's balanced salt solution . Superfusate fractions were collected at 15-min intervals after a 60-min stabilization superfusion period . LPS (100 ng/ml) and IL-6 receptor antagonist (IL-6ra) were then added to the superfusion medium over 1 h in two different experimental designs: (1) LPS only and (2) LPS followed by IL-6ra, performed in different experiments . This was followed by a washout period . The PO/MBH fragments were then subjected to a 56 mM K+ stimulus . Control PO/MBH fragments were continuously superfused with Earle's solution . As expected, LHRH release was significantly reduced (p < 0.05) during and following exposure to LPS . At the same time, IL-6 concentrations significantly increased in the superfusion medium compared with the control group . IL-6ra significantly (p < 0.01) potentiated the inhibitory effect of LPS on LHRH secretion . On the bases of previous papers indicating a stimulatory effect of IL-6 on LHRH release it could be considered that the potentiation of IL-6ra of the inhibitory effect of LPS on LHRH could be the consequence of the lack of the stimulatory effect of IL-6 on LHRH produced by the receptor antagonist . IL-6ra also increased IL-6 levels measured in medium probably due to a decrease in the metabolization induced by the blockage of the receptors and the consequent accumulation of IL-6 in the media . These results could indicate that IL-6 partly attenuates the inhibitory effect of LPS on LHRH release . These observations indicate that there is an increase in IL-6 release that becomes significant at the same time when LHRH release is decreased . Also, depolarizing concentrations of K+ (56 mM) did not increase IL-6 release, while LHRH release from the hypothalamic fragments was significantly increased . These data suggest that the inhibitory effect of LPS on LHRH release may be explained by the stimulation of other cytokines than IL-6, meanwhile the augmented levels of IL-6 probably released via a nonneuronal source was shown to be higher when LHRH was decreased . This could confirm the stimulatory role of IL-6 on LHRH release. Science, 1998 Jun 26, 280(5372), 2114 - 8 Type IV pili, transient bacterial aggregates, and virulence of enteropathogenic Escherichia coli; Bieber D et al.; Type IV bundle-forming pili of enteropathogenic Escherichia coli are required for the localized adherence and autoaggregation phenotypes . Whether these pili are also required for virulence was tested in volunteers by inactivating bfpA or bfpT (perA) encoding, respectively, the pilus subunit and the bfp operon transcriptional activator . Both mutants caused significantly less diarrhea . Mutation of the bfpF nucleotide-binding domain caused increased piliation, enhanced localized adherence, and abolished the twitching motility-dispersal phase of the autoaggregation phenotype . The bfpF mutant colonized the human intestine but was about 200-fold less virulent . Thus, BfpF is required for dispersal from the bacterial aggregate and for full virulence. Placenta, 1998 May, 19(4), 301 - 6 Stimulation of prostaglandin production from intact human fetal membranes by bacteria and bacterial products; Rajasingam D et al.; The addition of live or sonicated Escherichia coli, or endotoxin from E . coli increased the release of prostaglandins (PG) on both sides of intact human fetal membranes after 24 h of incubation, indicating that live bacteria were not required to activate prostaglandin production . Time-course studies showed that the levels of PGE2 and PGF2alpha on the fetal side of the membrane were increased 6 h after the addition of endotoxin, whereas levels on the maternal side increased within 1-2 h . These changes were independent of the side to which the endotoxin was added, indicating that a stimulatory factor passes through the fetal membranes . This factor is not endotoxin, which did not cross the membranes, and further studies are required to identify this endogenous stimulus . Prostaglandin metabolite levels were either unaffected or increased by endotoxin, indicating that the main effect is at the level of increased prostaglandin biosynthesis rather than decreased metabolism. Rev Sci Tech, 1998 Apr, 17(1), 200 - 19 Genetic resistance to bacterial diseases of animals; Adams LG et al.; Despite traditional disease control measures, losses attributable to infectious diseases continue to impede the livestock industries . An alternative approach to this problem is genetic disease resistance involving both immune and non-immune mechanisms, which is the inherent capacity of a previously unexposed animal to resist disease when challenged by pathogens . Although the nurturing environment influences variability in disease expression, natural resistance has been found to be inheritable and is transmitted from parent to offspring . Thus, an alternative approach to enhancing animal health management systems is to increase the overall level of genetic resistance at herd and population levels by using selective breeding programmes . The purpose of this review is to bring veterinarians, regulatory officials, industry representatives and animal technicians up to date with the principles and applications of genetic resistance as an adjunct to traditional interventions to control bacterial diseases of livestock . Although genetic resistance to bacterial diseases is often regulated by multiple genes controlling different processes of the host-pathogen interaction, the genetics of natural resistance is being unravelled increasingly by identification and characterisation of candidate genes, microsatellite markers and comparative gene mapping, to develop more practical methods of application. Curr Biol, 1998 Jun 4, 8(12), R408 - 11 Bacterial motility: secretory secrets of gliding bacteria; Youderian P; Many bacteria glide over surfaces without the aid of flagella . Gliding is still somewhat mysterious, but recent studies show that it involves specialized secretory systems that assemble membrane-associated filaments, and the recognition of extracellular components that trigger movement via transmembrane transducers. Int J Immunopharmacol, 1997 Sep-Oct, 19(9-10), 551 - 8 Bacterial cell wall components as immunomodulators--II . The bacterial cell wall extract OM-85 BV as unspecific activator, immunogen and adjuvant in mice; Bessler WG et al.; The bacterial extract Broncho-Vaxom used for the prevention and treatment of recurrent respiratory tract infections is an immunomodulator in vitro and in vivo, as determined in a murine model . The extract acts, on the one hand, as macrophage activator and polyclonal B-lymphocyte stimulant . On the other hand, after repeated intraperitoneal or oral immunizations, the extract is immunogenic, inducing serum IgG binding to the bacterial strains used for the preparation of the extract . On bacteria, the sera recognize the cell wall components porin, lipoprotein/lipopeptide and murein . The bacterial extract also exhibits adjuvant properties when applied in mixture with antigens, such as TNP-BSA or an influenza vaccine preparation . The unspecific and the immunospecific stimulatory effect of the extract as well as its adjuvant properties could be of importance for understanding its therapeutic effect. Cell Immunol, 1998 May 1, 185(2), 146 - 52 Regulation of cyclooxygenase-2 and endogenous cytokine expression by bacterial lipopolysaccharide that acts in synergy with c-kit ligand and Fc epsilon receptor I crosslinking in cultured mast cells; Moon TC et al.; Emerging evidence has suggested the pivotal role of mast cells in a host defense against bacterial infection . In this paper, we report that bacterial lipopolysaccharide (LPS) is a potent enhancer of the cytokine- and IgE-dependent delayed responses of IL-3-dependent mouse bone marrow-derived cultured mast cells (BMMC) . LPS, although showing minimal effects, significantly augmented the c-kit ligand (KL)- or IgE-dependent expression of cyclooxygenase (COX)-2 and the attendant delayed PGD2 generation, with IL-10 and IL-4 acting as potentiating and inhibitory cytokines, respectively . The COX-2-inducing activity of LPS was mimicked by exogenous IL-1 beta . Assessment of endogenous cytokine induction revealed that IL-1 beta expression was stimulated by either LPS or exogenous IL-1 beta . IL-6 expression occurred in parallel with COX-2 expression . IL-10 expression, which lagged behind COX-2 expression, depended on exogenous IL-10, but not on LPS and IL-1 beta . Thus, LPS and IL-1 beta exhibited similar biological activities in terms of COX-2 and endogenous cytokine expression . However, adding an antibody against the type I IL-1 receptor to BMMC, which abrogated the effects of IL-1 beta, failed to neutralize the effects of LPS . These results suggest that LPS activates BMMC through the signal transduction pathway shared with exogenous IL-1 beta, rather than exerting its action indirectly via the production of endogenous IL-1 beta. Proc Natl Acad Sci U S A, 1998 Jun 23, 95(13), 7333 - 8 Two binding modes reveal flexibility in kinase/response regulator interactions in the bacterial chemotaxis pathway; McEvoy MM et al.; The crystal structure at 2.0-A resolution of the complex of the Escherichia coli chemotaxis response regulator CheY and the phosphoacceptor-binding domain (P2) of the kinase CheA is presented . The binding interface involves the fourth and fifth helices and fifth beta-strand of CheY and both helices of P2 . Surprisingly, the two heterodimers in the asymmetric unit have two different binding modes involving the same interface, suggesting some flexibility in the binding regions . Significant conformational changes have occurred in CheY compared with previously determined unbound structures . The active site of CheY is exposed by the binding of the kinase domain, possibly to enhance phosphotransfer from CheA to CheY . The conformational changes upon complex formation as well as the observation that there are two different binding modes suggest that the plasticity of CheY is an essential feature of response regulator function. Plant Cell, 1998 Jun, 10(6), 1009 - 19 Two genes with similarity to bacterial response regulators are rapidly and specifically induced by cytokinin in Arabidopsis; Brandstatter I et al.; Cytokinins are central regulators of plant growth and development, but little is known about their mode of action . By using differential display, we identified a gene, IBC6 (for induced by cytokinin), from etiolated Arabidopsis seedlings, that is induced rapidly by cytokinin . The steady state level of IBC6 mRNA was elevated within 10 min by the exogenous application of cytokinin, and this induction did not require de novo protein synthesis . IBC6 was not induced by other plant hormones or by light . A second Arabidopsis gene with a sequence highly similar to IBC6 was identified . This IBC7 gene also was induced by cytokinin, although with somewhat slower kinetics and to a lesser extent . The pattern of expression of the two genes was similar, with higher expression in leaves, rachises, and flowers and lower transcript levels in roots and siliques . Sequence analysis revealed that IBC6 and IBC7 are similar to the receiver domain of bacterial two-component response regulators . This homology, coupled with previously published work on the CKI1 histidine kinase homolog, suggests that these proteins may play a role in early cytokinin signaling. Physiol Zool, 1998 May-Jun, 71(3), 294 - 302 Carbon release from purified chemoautotrophic bacterial symbionts of the hydrothermal vent tubeworm Riftia pachyptila; Felbeck H et al.; The gutless hydrothermal tubeworm Riftia pachyptila Jones relies mainly on its chemoautotrophic bacterial symbionts to supply nutrients in the form of secreted organic compounds resulting from fixation and incorporation of CO2 . In this study, symbionts were purified, tested for viability, and incubated in the presence of labeled CO2 . We demonstrated that purified symbionts can be used as a viable alternative to experiments with bacterial cultures . Several organic acids, sugars, and amino acids were labeled, but their fraction of the total label stayed generally constant during the incubation times used . However, increasing fractions of succinate and, to a lesser degree, glutamate were excreted into the incubation medium, indicating that these are probably the main carbon-containing compounds transferred from the symbionts to the host . Glutamate could also account for the transport of nitrogen from the symbionts to the host. Mol Microbiol, 1998 May, 28(3), 663 - 74 Legionella pneumophila DotA protein is required for early phagosome trafficking decisions that occur within minutes of bacterial uptake; Roy CR et al.; Numerous intracellular bacterial pathogens modulate the nature of the membrane-bound compartment in which they reside, although little is known about the molecular basis for this control . Legionella pneumophila is a bacterial pathogen able to grow within human alveolar macrophages and residing in a phagosome that does not fuse with lysosomes . This study demonstrates that the dotA product is required to regulate trafficking of the L . pneumophila phagosome . Phagosomes containing L . pneumophila dotA+ bacteria exhibited differential trafficking profiles when compared with isogenic dotA mutants . Phagosomes containing dotA mutants showed rapid accumulation of the lysosomal glycoprotein LAMP-1 as early as 5 min after uptake, whereas the majority of wild-type L . pneumophila phagosomes did not acquire LAMP-1 . The association of LAMP-1 with phagosomes containing dotA mutant bacteria was concomitant with the appearance of the small GTP-binding protein Rab7 on the vacuolar membrane . These data demonstrate that phagosomes containing replication-competent L . pneumophila evade early endocytic fusion events . In contrast, the kinetics of LAMP-1 and Rab7 association indicate that the dotA mutants are routed along a well-characterized endocytic pathway leading to fusion with lysosomes . Genetic studies show that L . pneumophila requires DotA expression before macrophage uptake in order to establish an intracellular site for replication . However, the bacteria do not appear to require continuous expression of the DotA protein to maintain a replicative phagosome . These data indicate that DotA is one factor that plays a fundamental role in regulating initial phagosome trafficking decisions either upon or immediately after macrophage uptake. AIDS, 1998 May 28, 12(8), 885 - 93 Clinical predictors of Pneumocystis carinii pneumonia, bacterial pneumonia and tuberculosis in HIV-infected patients; Selwyn PA et al.; BACKGROUND: Clinicians are frequently faced with the differential diagnosis between Pneumocystis carinii pneumonia (PCP), bacterial pneumonia, and pulmonary tuberculosis in HIV-infected patients . OBJECTIVES: To identify features that could help differentiate these three pneumonia types at presentation by evaluating the clinical characteristics of the three diagnoses among patients at two urban teaching hospitals . DESIGN: Retrospective chart review . METHODS: Cases were HIV-infected patients with a verified hospital discharge diagnosis of PCP (n = 99), bacterial pneumonia (n = 94), or tuberculosis (n = 36) . Admitting notes were reviewed in a standardized manner; univariate and multivariate analyses were used to determine clinical predictors of each diagnosis . RESULTS: Combinations of variables with the highest sensitivity, specificity, and odds ratios (OR) were as follows: for PCP, exertional dyspnea plus interstitial infiltrate (sensitivity 58%, specificity 92%; OR, 16.3); for bacterial pneumonia, lobar infiltrate plus fever < or = 7 days duration (sensitivity 48%, specificity 94%; OR, 14.6); and for tuberculosis, cough > 7 days plus night sweats (sensitivity 33%, specificity 86%; OR, 3.1) . On regression analysis, independent predictors included interstitial infiltrate (OR, 10.2), exertional dyspnea (OR, 4.9), and oral thrush (OR, 2.9) for PCP; rhonchi on examination (OR, 12.4), a chart mention of 'toxic' appearance (OR, 9.1), fever < or = 7 days (OR, 6.6), and lobar infiltrate (OR, 5.8) for bacterial pneumonia; and cavitary infiltrate (OR, 21.1), fever > 7 days (OR, 3.9), and weight loss (OR, 3.6) for tuberculosis . CONCLUSIONS: Simple clinical variables, all readily available at the time of hospital admission, can help to differentiate these common pneumonia syndromes in HIV-infected patients . These findings can help to inform clinical decision-making regarding choice of therapy, use of invasive diagnostic procedures, and need for respiratory isolation. Cent Afr J Med, 1998 Jan, 44(1), 11 - 5 Acute bacterial meningitis in a developing country: diagnosis related mortality among paediatric patients; Imananagha KK et al.; OBJECTIVES: To evaluate the effect of late diagnosis and other factors on outcome of paediatric bacterial meningitis (BM) and recommend appropriate intervention . DESIGN: Case series . SETTING: University of Calabar Teaching Hospital, Calabar, Nigeria . SUBJECTS: 62 consecutive BM patients aged two months to 16 years admitted between 1991 and 1994 . MAIN OUTCOME MEASURES: Mortality rate . RESULTS: Diagnostic difficulties experienced in 58% of cases and other factors resulted in delayed diagnosis and high mortality (20 to 47%) . CONCLUSION: Only elimination of the identified inadequacies in management can significantly reduce the BM-related high mortality in developing countries. Mutat Res, 1998 May 11, 414(1-3), 95 - 105 A novel bacterial reversion and forward mutation assay based on green fluorescent protein; Cariello NF et al.; We report the first use of green fluorescent protein (GFP) for mutation detection . We have constructed a plasmid-based bacterial system whereby mutated cells fluoresce and non-mutated cells do not fluoresce . Fluorescence is monitored using a simple hand-help UV lamp; no additional cofactors or manipulations are necessary . To develop a reversion system, we introduced a +1 DNA frameshift mutation in the coding region of GFP and the resulting protein is not fluorescent in Escherichia coli . Treatment of bacteria containing the +1 frameshift vector with ICR-191 yields fluorescent colonies, indicating that reversion to the wild-type sequence has occurred . Site-directed mutagenesis was used to insert an additional cytosine into a native CCC sequence in the coding region of GFP in plasmid pBAD-GFPuv, expanding the sequence to CCCC . A dose-related increase in fluorescent colonies was observed when the bacteria were treated with ICR-191, an agent that induces primarily frameshift mutations . The highest dose of ICR-191 tested, 16 microg/ml, produced a mutant fraction of 16 x 10(-5) and 8.8 x 10(-5) in duplicate experiments . The reversion system did not respond to MNNG, an agent that produces mainly single-base substitutions . To develop a forward system, we used GFP under the control of the arabinose PBAD promoter; in the absence of arabinose, GFP expression is