Zh Mikrobiol Epidemiol Immunobiol, 1993 May-Jun, (3), 39 - 43 {The mathematical modelling of a dynamic epidemic process with a change in the infectivity of the causative agent of an infectious disease}; Beliakov VD et al.; The influence of changes in epidemic parameters on the time course of the disease manifestations was under study . An attempt to determine the relationship between such epidemic signs as the infectiousness of the parasite population (the transfer factor P) and morbidity and to study the influence of P on the seasonal and cyclic patterns of morbidity by modeling the process was made . The relationship between the quantitative parameters of "infectiousness" and "infectiousness profile" of the causative agent and morbidity was established . Seasonal and cyclic fluctuations of the modeled epidemic process were explained by the annual changes, constituting some percent shares of its constant value. Appl Environ Microbiol, 1993 May, 59(5), 1565 - 72 Production and characterization of monoclonal antibodies specific for Shewanella colwelliana exopolysaccharide; Sledjeski DD et al.; Six monoclonal antibodies were produced to whole cells of Shewanella colwelliana (Aco1 to Aco6) and two (Aco22 to Aco23) to purified exopolysaccharide (EPS) . Aco1, -4 to -6, -22, and -23 bound to both the cell surface and the purified EPS, while Aco2 and -3 bound to cells only . The EPS of S . colwelliana was antigenically unique from those of nine other species of marine bacteria that were tested . Mapping studies revealed that all of the EPS-specific monoclonal antibodies bound to the same epitope . This EPS epitope was sensitive to cleavage of ester bonds, but neither pyruvate, acetate, nor terminal nonreducing sugars were required for antigenicity . When S . colwelliana was grown on rich media, most of its EPS was loosely associated with the cell surface. Proc Natl Acad Sci U S A, 1993 May 1, 90(9), 4191 - 5 Images of evolution: origin of spontaneous RNA replication waves; McCaskill JS et al.; Self-replicating molecules set up traveling concentration waves that propagate in an aqueous enzyme solution . The velocity of each wave provides an accurate (+/- 0.1%) noninvasive measure of fitness for the RNA species currently growing in its front . Evolution may be followed from changes in the front velocity, and these differ from wave to wave . Thousands of controlled evolution reactions in traveling waves have been monitored in parallel to obtain quantitative images of the stochastic process of natural selection . An RNA polymerase (RNA-dependent RNA nucleotidyltransferase, EC 2.7.7.6), extracted from bacteria infected by the Q beta RNA virus, catalyzes the replication . The traveling waves that arise spontaneously without added RNA provide a model system for major evolutionary change. Oncogene, 1993 May, 8(5), 1119 - 26 Regulation of c-Src tyrosine kinase activity by the Src SH2 domain; Liu X et al.; The protein-tyrosine kinase activity of pp60c-src (c-Src) is inhibited by phosphorylation of tyr527, within the c-Src c-terminal tail . Genetic and biochemical data have suggested that this negative regulation requires an intact Src homology 2 (SH2) domain . Since SH2 domains recognize phosphotyrosine, it is possible that these two non-catalytic domains associate, and thereby repress c-Src kinase activity . Consistent with this model, an isolated Src SH2 domain expressed in bacteria as a GST fusion protein bound in vitro to a synthetic phosphotyrosine-containing peptide modeled on the C-terminal 13 residues of the c-Src tail . Binding was absolutely dependent on phosphorylation of tyr527 in the tail peptide, and was modified by both the length and sequence of the peptide . Competition experiments indicated only a moderate binding affinity between the Src SH2 domain and the phosphorylated tail . A distinct phosphotyrosine-containing peptide previously identified as binding the Src SH2 domain with high affinity stimulated c-Src tyrosine kinase activity in vitro, possibly by competing with the endogenous tail phosphorylation site for binding to the SH2 domain . Indeed, this activation was competitively inhibited by purified bacterial Src SH2 domain . These data provide direct evidence that the c-Src tail has an intrinsic affinity for the Src SH2 domain, and suggest that such an interaction in the intact molecule contributes to maintaining c-Src in an inactive form. Biochem Biophys Res Commun, 1993 Apr 30, 192(2), 754 - 9 Identification of active-site residues in Aspergillus ficuum extracellular pH 2.5 optimum acid phosphatase; Ullah AH et al.; Primary structure elucidation of peptides generated by cyanogen bromide, endoproteinase Glu-C, and clostripain cleavage of an Aspergillus ficuum extracellular pH optimum 2.5 acid phosphatase identified a region which contains the active site of the enzyme . The 23-residue segment contains the fragment RHGXRXP, which is homologous to acid phosphatase from Saccharomyces spp., Aspergillus ficuum, mammals, and bacteria . Homologous or conservative substitutions are observed in the 10-amino acid fragment preceding this region. Gene, 1993 Apr 30, 126(2), 237 - 42 Cloning and structural organization of a xylanase-encoding gene from penicillium chrysogenum; Haas H et al.; The filamentous fungus, Penicillium chrysogenum, is able to grow on xylan as a sole carbon source . Under these conditions, high levels of a xylanase (XYLP) are secreted into the medium . After purification and characterization of this enzyme, we have isolated both the encoding cDNA and the genomic sequence by using oligodeoxyribonucleotides derived from partial amino acid (aa) sequences of the purified enzyme . The gene is approximately 1.6 kb in length, and comparison of the nucleotide (nt) sequence of the genomic and the cDNA clone revealed the presence of ten exons and nine introns . All intron/exon splice junctions exactly follow the GT/AG rule, except for the seventh intron which shows atypical AT/AC splice sites . The immediate 5'-flanking region of the first exon contains one putative CCAAT consensus sequence and a perfect TATA box . Primer extension analysis revealed two transcription start points located 38 and 34 nt upstream from the ATG start codon . A sequence of 23 aa representing a typical signal peptide is present at the N terminus of the deduced aa sequence . Northern blot analysis of total cellular RNA indicated that xylP encodes a 1.3-kb transcript which is induced by xylan . The aa sequence of XYLP shows considerable homology to high-M(r) acidic xylanases (Xln) and cellulases from different bacteria, yeasts and fungi. FEBS Lett, 1993 Apr 26, 321(2-3), 135 - 9 Amino acid sequence similarities between low molecular weight endo-1,4-beta-xylanases and family H cellulases revealed by clustering analysis; Torronen A et al.; The amino acid sequences of seventeen family G xylanases and the two known family H cellulases have been compared by hydrophobic cluster analysis . A weak but significant similarity was demonstrated between these two families suggesting that these enzymes share the same molecular mechanism and catalytic residues and that they have related 3D folds . The major differences were found in the N-terminal regions. J Biol Chem, 1993 Apr 25, 268(12), 9005 - 13 Structural and functional domains of the Drosophila ncd microtubule motor protein; Chandra R et al.; Nonclaret disjunctional (ncd) is a kinesin-related microtubule motor protein that is required for proper chromosome distribution in Drosophila . Despite its sequence similarity to kinesin heavy chain, ncd translocates with the opposite polarity as kinesin, toward microtubule minus ends . We have expressed different regions of the protein in bacteria and analyzed the proteins for function . Results indicate that ncd consists of three domains: a basic, proline-rich N-terminal "tail," a central alpha-helical coiled-coil stalk, and a C-terminal motor domain . The ncd N terminus proteins bundle microtubules in motility assays and show ATP-independent binding to microtubules in solution . Truncated proteins, lacking the tail but containing the predicted motor domain and differing lengths of the stalk, did not support microtubule gliding in in vitro assays but showed microtubule-stimulated MgATPase activity in solution . Addition of a nonspecific N terminus to two of the truncated proteins restored directional gliding and rotation of microtubules in motility assays, demonstrating that these properties map to the predicted mechanochemical domain of ncd . Physical properties of the C terminus proteins indicate that the stalk region is important for dimerization and that the ncd protein probably exists and functions as a dimer. Nucleic Acids Res, 1993 Apr 25, 21(8), 1889 - 93 Construction of recombinant DNA by exonuclease recession; Yang YS et al.; We describe a new exonuclease-based method for joining and/or constructing two or more DNA molecules . DNA fragments containing ends complementary to those of a vector or another independent molecules were generated by the polymerase chain reaction . The 3' ends of these molecules as well as the vector DNA were then recessed by exonuclease activity and annealed in an orientation-determined manner via their complementary single-stranded regions . This recombinant DNA can be transformed directly into bacteria without a further ligase-dependent reaction . Using this approach, we have constructed recombinant DNA molecules rapidly, efficiently and directionally . This method can effectively replace conventional protocols for PCR cloning, PCR SOEing, DNA subcloning and site-directed mutagenesis. Cell, 1993 Apr 23, 73(2), 395 - 406 Functional analysis of a growth factor-responsive transcription factor complex; Hill CS et al.; Serum response factor (SRF) forms a ternary complex at the c-fos serum response element (SRE) with an accessory factor, Elk-1 . We constructed altered-binding specificity derivatives of SRF and Elk-1 that form a ternary complex at a mutated, inactive SRE; like Elk-1, the Elk-1 variant only binds its target as part of a ternary complex with SRF . Simultaneous expression of these SRF and Elk-1 derivatives restores serum-regulated activity to the mutated SRE in transfected cells . Efficient transcriptional activation is dependent on the regulated phosphorylation of Elk-1 C-terminal MAP kinase sites and requires the C-terminal sequences of SRF as well as SRF sequences that mediate ternary complex formation . These experiments provide direct evidence that SRF and Elk-1 functionally cooperate in the ternary complex at the SRE to regulate transcription. J Chromatogr, 1993 Apr 21, 614(1), 7 - 17 Gas chromatographic characterization of free D-amino acids in the blood serum of patients with renal disorders and of healthy volunteers; Bruckner H et al.; A capillary gas chromatographic method, using the chiral stationary phase Chirasil-L-Val, after treatment and isolation with Dowex 50W X8 cation exchanger and conversion into trifluoroacetyl-1-propyl esters or pentafluoropropionyl-1 (or 2)-propyl esters, has been developed for the determination of the relative amounts of free D-amino acids in the blood serum of eighteen patients with renal failure (continuous ambulatory peritoneal dialysis (CAPD), n = 11; hemodialysis, n = 5; nephrotic syndrome, n = 2) and compared with data obtained from healthy volunteers (n = 5) . Significant amounts of D-Ala (0.5-13%) and D-Asx (1.5-7.7%; Asx = Asp + Asn) were found in all serum samples . D-Ser was detected in the serum of all patients with renal disorders and, in addition, D-Pro (0.6-2.5%) was found in the serum of all patients undergoing hemodialysis and with nephrotic syndrome . D-Ser (2.9-3.1%) and D-Pro (0.6-0.9%) were also found in the samples of three volunteers . D-Leu (1.2-1.7%) was present in three patients with CAPD, and D-Glx (0.3-1.3%; Glx = Glu + Gln) was present in eight of eighteen patients with renal malfunction . Linear regression analysis of the relative amounts of D-amino acids and the serum creatinine levels of all donors revealed positive correlation factors for D-Asx (r = 0.748) and D-Ser-(r = 0.667), but not for D-Pro and D-Ala . Remarkably high amounts of D-Ser (12.1 and 19.8%) were found in two hemodialysates investigated . Participation of intestinal bacteria and nutrition are discussed as possible sources of serum D-amino acids . An increase of some D-amino acids in the serum of patients with renal diseases might be explained, in part, by decreased activity of renal D-amino acid oxidase. Proc Natl Acad Sci U S A, 1993 Apr 15, 90(8), 3309 - 13 Genes for a microaerobically induced oxidase complex in Bradyrhizobium japonicum are essential for a nitrogen-fixing endosymbiosis; Preisig O et al.; We report the discovery of a Bradyrhizobium japonicum gene cluster (fixNOQP) in which mutations resulted in defective soybean root-nodule bacteroid development and symbiotic nitrogen fixation . The predicted, DNA-derived protein sequences suggested that FixN is a heme b and copper-binding oxidase subunit, FixO a monoheme cytochrome c, FixQ a polypeptide of 54 amino acids, and FixP a diheme cytochrome c and that they are all membrane-bound . The isolation and analysis of membrane proteins from B . japonicum wild-type and mutant cells revealed two c-type cytochromes of 28 and 32 kDa as the likely products of the fixO and fixP genes and showed that both were synthesized only under oxygen-limited growth conditions . Furthermore, fixN insertion and fixNO deletion mutants grown microaerobically or anaerobically (with nitrate) exhibited a strong decrease in whole-cell oxidase activity as compared with the wild type . The data suggest that the fixNOQP gene products are induced at low oxygen concentrations and constitute a member of the bacterial heme/copper cytochrome oxidase superfamily . The described features are compatible with the postulate that this oxidase complex is specifically required to support bacterial respiration in endosymbiosis. J Gen Microbiol, 1993 Apr, 139 ( Pt 4), 687 - 94 Location of the genes for anthranilate synthase in Streptomyces venezuelae ISP5230: genetic mapping after integration of the cloned genes; Paradkar AS et al.; The anthranilate synthase (trpEG) genes in Streptomyces venezuelae ISP5230 were located by allowing a segregationally unstable plasmid carrying cloned S . venezuelae trpEG DNA and a thiostrepton resistance (tsr) marker to integrate into the chromosome . The integrated tsr was mapped by conjugation and transduction to a location close to tyr-2, between arg-6 and trpA13 . A genomic DNA fragment containing trpC from S . venezuelae ISP5230 was cloned by complementation of a trpC mutation in Streptomyces lividans . Evidence from restriction enzyme analysis of the cloned DNA fragments, from Southern hybridization using the cloned trp DNA as probes, and from cotransduction frequencies, placed trpEG at a distance of 12-45 kb from the trpCBA cluster . The overall arrangement of tryptophan biosynthesis genes in the S . venezuelae chromosome differs from that in other bacteria examined so far. Semin Cancer Biol, 1993 Apr, 4(2), 119 - 28 The induction of gene expression in mammalian cells by radiation; Keyse SM; A large number of genes have now been shown to be inducible in response to radiation in mammalian cells and tissues . Based on extensive studies of stress inducible regulons in bacteria, it is assumed that at least some of the proteins encoded by these genes are involved in an adaptive response to the lethal effects of radiation . Here I review the biological evidence for adaptation, and analyse the functions of radiation inducible genes in the context of their possible roles in cellular protection . Recent progress has been made in understanding how cells sense radiation induced damage . The signal transduction pathways which end in the activation of specific genes is summarized. Rinsho Ketsueki, 1993 Apr, 34(4), 411 - 7 {Current status of transfusion-transmitted infection}; Shimizu M; Recently transfusion-transmitted infections (TTI) have been decreased remarkably . Especially nonA, nonB posttransfusion hepatitis (PTH) has reduced to one third by introducing anti-HCV (C100-3) antibody screening . HCV-PTH will be lowered more with screening by the 2nd generation reagent of HCV . None of cases with HIV infection by transfusion has been reported since introduction of anti-HIV antibody screening, but we have to watch out it, due to rapid increase of heterosexual infection of HIV during this one year in Japan . Voluntary blood donors should warrant blood safety by their own responsibility . We have no cases with malaria by transfusion for these several years . There are no reported cases with Chagas' disease in Japan, but increase of international immigrations will be potential to introduce these infections by transfusion into Japan . Recently TTI by bacteria-contaminated blood have been very rare owing to technical improvement of blood-drawing . However, platelet concentrates stored at 22 degrees C for 3-5 days and red cell products stored at 4 degrees C for 35-42 days have presented new problems concerning bacterial contamination . We have to consider these problems concerning bacterial contamination. Curr Opin Cell Biol, 1993 Apr, 5(2), 261 - 4 EGF: new tricks for an old growth factor; Carpenter G; During the past year, the biology of epidermal growth factor (EGF) has been investigated in lower organisms (Caenorhabditis elegans, Drosophila and bacteria) . These experiments have produced some surprising results: the identification of defects produced by mutation of EGF-like genes; the role of EGF receptors in bacterial invasion; and the role of EGF-like precursors as receptors for a bacteria toxin. J Clin Pathol, 1993 Apr, 46(4), 318 - 22 Use of PCR in routine diagnosis of treated and untreated pulmonary tuberculosis; Yuen KY et al.; AIMS--To assess the routine use of a polymerase chain reaction (PCR) assay for the direct detection of Mycobacterium tuberculosis in expectorated sputum specimens . METHODS--A pair of primers (20-mer) were designed to amplify the 38 kilodalton protein of M tuberculosis . The specificity of the assay was evaluated in 31 M tuberculosis strains, 15 atypical mycobacterium species, and several commensal bacteria of the upper respiratory tract . The assay was subsequently applied to 519 sputum specimens from 85 inpatients of a chest hospital in Hong Kong . RESULTS--An amplified product of 239 base pairs was found in all M tuberculosis strains, standard strains of M bovis, and M africanum but not in the other bacterial strains tested . For the 51 patients with pulmonary radiographic lesions, the diagnosis of pulmonary tuberculosis was subsequently confirmed by both culture and PCR in 41 of them . Five patients who were treated before admission were positive by PCR alone . All but one patient in the control group (patients with acute exacerbation of chronic obstructive airway diseases) or those with atypical mycobacterial diseases were PCR negative . The PCR remained positive after four weeks of anti-tuberculosis treatment in 29 patients, 16 of whom had become culture negative . CONCLUSION--This PCR assay is a useful technique for the diagnosis of untreated and recently treated cases of pulmonary tuberculosis. Gut, 1993 Apr, 34(4), 489 - 93 Presence of N-acyl and acetoxy derivatives of putrescine and cadaverine in the human gut; Murray KE et al.; N-acyl and acetoxy derivatives of putrescine and cadaverine have been found in the faeces of children and in cultures of isolates of gut bacteria . The evidence was accumulated from two dimensional, thin layer chromatography, field desorption mass spectrometry, and accurate mass measurement of the DANS derivatives of the amines . The acetoxy compounds of putrescine and cadaverine have not previously been reported. Crit Care Clin, 1993 Apr, 9(2), 363 - 76 Metabolic and nutritional support of the intensive care patient . Ascending the learning curve; Kaminski MV Jr et al.; The learning curve of nutritional support in the critically ill began with the amelioration of the effects of starvation in patients with a disabled intestine . Next, there was an appreciation that feeding formulas could be tailored to support patients with specific organ insufficiencies . Then it was realized that feeding enterally has distinct advantages over feeding parenterally . In addition to a decrease in catheter-related sepsis, there was noted a distinct decrease in "remote site" sepsis . In fact, good scientific reasons have been identified to explain why this occurs, such as maintaining the competency of the intestine against a translocation of endotoxin and bacteria and "turn-on" of the stress response . Further, we now know that specific nutrients can produce desirable pharmacologic effects . In the future, feeding formulae will be devised that continue to modify the patient's response to illness favorably . Another important consideration is to begin nutritional support as soon as possible--i.e., on the day of admission, if appropriate . The critical care specialist should be expert in these techniques, with the goal of eliminating malnutrition as a confounding variable in the clinical course of the intensive care unit patient. Glycobiology, 1993 Apr, 3(2), 185 - 90 Expression and characterization of a carbohydrate-binding fragment of rat aggrecan; Saleque S et al.; The COOH-terminal portion of cartilage proteoglycan core protein, aggrecan, expressed by in vitro translation, binds carbohydrate-containing affinity columns . The in vitro expression approach has been used to define the sugar-binding portion of the core protein . The active fragment, which corresponds closely to the carbohydrate-recognition domains in the family of Ca(2+)-dependent (C-type) animal lectins, has been expressed in bacteria and characterized . The CD spectrum of the domain is very similar to the spectrum of the binding domain of serum mannose-binding protein, suggesting that its overall structure probably resembles the known three-dimensional structure of the mannose-binding domain . The binding specificity of the core protein fragment has been characterized using a solid-phase assay . The results suggest that the monosaccharide-binding site is also similar to that in other C-type carbohydrate-recognition domains. J Appl Bacteriol, 1993 Apr, 74(4), 417 - 20 Comparison of Signal and Bactec NR-660 blood culture systems; Stevens M et al.; The Signal blood culture system was compared with the Bactec NR-660 . A total of 1617 blood culture sets yielded 143 (8.8%) significant isolates; 113 (79.0%) were from positive bottles in both the Bactec and Signal systems . Twelve organisms (8.4%) were detected and isolated from the Signal system only and another 18 (12.6%) from the Bactec system only . Of these 18, five were Signal-positive but the organism was not recovered and four organisms were isolated from negative Signal bottles on terminal subculture . The time taken to detection for each system was similar; the Signal system detected 68% and the Bactec 63% of significant positives within 24 h . At 48 h Bactec detected 91% and the Signal 85% . A significantly-reduced number of bottles which gave a positive signal but were negative by microscopical and cultural methods was found, compared with previous reports . The 1 h incubation period prior to the insertion of the Signal growth indicator device was considered to be the cause of this reduction in the proportion of false positives . Fifty-five percent (42/77) of the Bactec false positives were due to delta growth value . This is when there is an increase in the growth index of > or = 15 without the positive threshold level of 30 being attained . This occurred in the anaerobic bottle on day 2 with 42 bottles . Another 40% (31/77) of the false positives had a growth value between the positive threshold of 30 and a value of 35 . Eighty (4.9%) of Bactec and 65 (4.0%) of Signal sets yielded clinically non-significant isolates.(ABSTRACT TRUNCATED AT 250 WORDS) FEMS Microbiol Lett, 1993 Apr 1, 108(2), 169 - 74 Interaction of a trypsin-like enzyme of Porphyromonas gingivalis W83 with antithrombin III; Curtis MA et al.; We have previously observed that trypsin-like activity in Porphyromonas gingivalis culture supernatants is inhibitable by the plasma arg-serpin antithrombin III (ATIII) . This report demonstrates that a partially purified P . gingivalis trypsin-like enzyme (M(r) 47,000) is inhibited by ATIII with an association rate constant (k(ass)) of 5.65 x 10(4) M-1 s-1 but does not form SDS-stable complexes . Heparin enhances the k(ass) and stabilizes the complexes but in either case such inhibition is temporary and results in ATIII inactivation by reactive centre proteolysis between R393-S394 . In the absence of heparin this is accompanied by N-terminal cleavage between K39-I40. Unfallchirurg, 1993 Apr, 96(4), 176 - 80 {Opportunistic infections in patients with disordered immune status}; Kossmann T et al.; Dysfunction of the immune system can result in opportunistic infections, which are frequently responsible for high morbidity and mortality . With regard to surgery, opportunistic infections are found in specific risk groups, including individuals with tumors, AIDS, thermic or mechanical trauma and organ transplantation . These infections can be caused by bacteria, fungi, viruses and protozoa . If there are indications of a possible opportunistic infection, a rapid diagnosis is required, followed by immediate therapeutic intervention. Pharm Res, 1993 Apr, 10(4), 606 - 10 Distinction between the depletion of opsonins and the saturation of uptake in the dose-dependent hepatic uptake of liposomes; Harashima H et al.; Opsonins play a role in the hepatic uptake of particles such as bacteria, lipid emulsion, and liposomes . The objective of this study was to distinguish between opsonin depletion and uptake saturation in the dose-dependent hepatic uptake of liposomes . The uptake of opsonized and unopsonized liposomes was determined in the isolated perfused liver . Serum (2.9 mL) was required to opsonize 1 mumol liposomes fully, indicating that a rat (250 g with 10 mL of serum) can opsonize 3.5 mumol liposomes . Next the dose effect on hepatic uptake of opsonized and unopsonized liposomes was examined . Saturation of uptake was found only for the opsonized liposomes . On the other hand, the hepatic uptake clearance decreased dose dependently from 4.31 to 0.79 (mL/min), with increasing doses from 0.075 to 17 mumol/250 g, respectively, after i.v . administration . Thus, the decrease in the hepatic uptake clearance at the medium dose was due to the saturation of uptake alone, and at the high dose it was due to opsonin depletion as well . These results show that the saturation of liposomal uptake in the liver and the depletion of opsonins occurred at different liposome dosage levels. J Pediatr Surg, 1993 Apr, 28(4), 601 - 5 Mucosal permeability to 51Cr EDTA following subclinical intestinal ischemia-reperfusion injury in the weanling rat; Langer JC et al.; The etiology of necrotizing enterocolitis (NEC) is uncertain . We have hypothesized that subclinical intestinal ischemia might result in increased mucosal permeability to intraluminal toxins or bacteria, resulting in inflammation and NEC . In order to pursue this hypothesis, we designed a series of studies to investigate whether the first assumption is correct, ie whether a subclinical ischemia-reperfusion injury (IRI) results in increased mucosal permeability . Using a model of superior mesenteric artery occlusion (SMAO) in weanling rats, we initially defined 10-minute SMAO as "subclinical" IRI (ie, 100% survival, no histological changes, and no hemodynamic instability) . Mucosal permeability to a standard probe molecule (51Cr EDTA) was then measured after sham operation, or 2-minute or 10-minute SMAO . There was an early increase in permeability 30 minutes after reperfusion in the 10-minute SMAO group, which was completely reversed by 2 hours . Further studies suggested that having passed through the mucosa, the probe entered the systemic circulation via both portal venous and intestinal lymphatic routes . Subclinical intestinal IRI results in an early, reversible increase in mucosal permeability to 51Cr EDTA, which may be important in the pathogenesis of NEC . Further studies are required to fully characterize this phenomenon, and to determine the mechanisms by which it occurs. J Anim Sci, 1993 Apr, 71(4), 963 - 7 Microbially detoxified vomitoxin-contaminated corn for young pigs; He P et al.; A performance trial was conducted to evaluate the effect of microbially detoxified moldy corn in a corn-soybean meal-based starter diet for young pigs . Moldy corn containing 450 ppm of vomitoxin replaced clean corn in a control diet to give a diet containing 5 ppm of vomitoxin . The same amount of moldy corn was microbially detoxified by incubation with the contents of the large intestine of chickens (CLIC) and then incorporated into the control diet to give a "detoxified" vomitoxin diet, which contained 2.1 ppm of vomitoxin . A paired diet was formulated by incorporating the untreated moldy corn into the control diet to give a diet containing the same level of vomitoxin as the "detoxified" vomitoxin diet . Clean corn was also treated with CLIC and replaced corn in the control diet to give a biologically treated control diet . Each diet was fed to six pigs (three gilts and three boars) for 5 d and then all pigs were changed to the control diet for a further 5-d feeding period . During the first 5-d feeding period, no differences were observed in pigs fed either the control diet or the biologically treated control diet . A diet containing 5 ppm of vomitoxin decreased the pigs' daily feed consumption, weight gain, and feed efficiency by 25, 57, and 45%, respectively, compared with the control diet (P < or = .05) . Daily feed intake, weight gain, and feed efficiency in pigs fed the "detoxified" vomitoxin diet were 19, 54, and 37% greater, respectively, than for pigs fed the vomitoxin diet (P < or = .05).(ABSTRACT TRUNCATED AT 250 WORDS) Am J Physiol, 1993 Apr, 264(4 Pt 1), C761 - 82 Transport of lactate and other monocarboxylates across mammalian plasma membranes; Poole RC et al.; Transport of L-lactate across the plasma membrane is of considerable importance to almost all mammalian cells . In most cells a specific H(+)-monocarboxylate cotransporter is largely responsible for this process; the capacity of this carrier is usually very high, to support the high rates of production or utilization of L-lactate . The best characterized H(+)-monocarboxylate transporter is that of the erythrocyte membrane, which transports L-lactate and a wide range of other aliphatic monocarboxylates, including pyruvate and the ketone bodies acetoacetate and beta-hydroxybutyrate . This carrier is inhibited by alpha-cyanocinnamate derivatives and some stilbene disulfonates and has been identified as a protein of 35-50 kDa on the basis of purification and specific labeling experiments . Other cells possess similar alpha-cyanocinnamate-sensitive H(+)-linked monocarboxylate transporters, but in some cases there are significant differences in the properties of these systems, sufficient to suggest the existence of a family of such carriers . In particular, cardiac muscle and tumor cells have transporters that differ in their Km values for certain substrates (including stereoselectivity for L- over D-lactate) and in their sensitivity to inhibitors . Mitochondria, bacteria, and yeast also possess H(+)-monocarboxylate transporters that share some properties in common with those in the mammalian plasma membrane but are adapted to their specific roles . However, there are distinct Na(+)-monocarboxylate cotransporters on the luminal surface of intestinal and kidney epithelia, which enable active uptake of lactate, pyruvate, and ketone bodies in these tissues . This article reviews the properties of these transport systems and their role in mammalian metabolism. J Dent, 1993 Apr, 21(2), 94 - 8 Copper plate replica SEM of developing dental plaque in monkeys (Macaca fascicularis); Radford JR et al.; The aim of the study was to examine the development of dental plaque in macaque monkeys (Macaca fascicularis) . Copper plate replicas were constructed from impressions of the labial surface of one of the upper central incisor teeth after tooth cleaning and when plaque had accumulated for 12, 24 and 48 h in each of five animals . Scanning electron microscope examination of the replicas showed that bacteria were present on the tooth surface as scattered individual cells, which after 24 h had formed a continuous layer . Both coccoid and filamentous bacteria were visible in 48-hour-old plaque . Such a rapid accumulation of potentially periodontopathic dental plaque emphasizes the importance of regular and meticulous oral hygiene. Am J Gastroenterol, 1993 Apr, 88(4), 604 - 7 Intestinal perforation due to Mycobacterium tuberculosis in HIV-infected individuals: report of two cases; Friedenberg KA et al.; Intestinal perforation is an extremely uncommon complication of Mycobacterium tuberculosis (MTB) infection . We describe two cases of multiple intestinal perforations secondary to MTB in individuals infected with the human immunodeficiency virus (HIV) presenting at the Los Angeles County-University of Southern California Medical Center over a 2-month period . For each case, this was the first presentation of AIDS . One of the two patients had concurrent pulmonary involvement . One patient died, and the other responded to therapy and was discharged in stable condition . The most striking finding in both cases was the extremely large number of acid-fast bacteria seen transmurally on the pathological specimens . This might be related to impaired T-cell function . The resurgence of MTB infection in North America, in the presence of the AIDS epidemic, may result in an increasing frequency of unusual presentations, such as intestinal perforation . Intestinal perforation due to MTB should be considered in HIV-infected patients presenting with an acute abdomen. Scand J Clin Lab Invest, 1993 Apr, 53(2), 171 - 7 Luminol enhanced Fc-receptor dependent chemiluminescence from peripheral PMN cells . A methodological study; Bergstrom K et al.; Maximal luminol enhanced chemiluminescence (CL) of PMN cells after Fc-gamma-receptor stimulation is a way to study the cell activity in connection with phagocytic function . Optimal conditions for such a method were elaborated for practical clinical use . After blood sampling and gentle mixing the blood sample was allowed to stand at +20 degrees C for not more than 1 h . The PMN cells prepared at +20 degrees C were washed at +4 degrees C with a phosphate buffer containing human serum albumin . A gentle lysis of the red blood cells with NH4Cl solution reduced the number of red cells sufficiently not to interfere with the CL . Important factors for the precision of the method were reproducible amounts of bacteria and a reproducible mixing of the particles during the CL analysis . The method had a variation (CV) of 10-15% in healthy individuals. Anesthesiology, 1993 Apr, 78(4), 700 - 6 Inhibition of interferon stimulation of natural killer cell activity in mice anesthetized with halothane or isoflurane; Markovic SN et al.; BACKGROUND: Basal cytotoxic activity of NK cells, a subtype of lymphocytes involved in the nonspecific immune response to viruses, tumors, and some bacteria, is altered in the postoperative period . The current study examines the effects of halothane and isoflurane on interferon-induced stimulation of NK cell cytotoxicity in vivo and in vitro . METHODS: Mice were exposed to either anesthetic on days 10, 5, 1, or -1 relative to interferon treatment on day 0 . NK cytotoxicity was assessed 24 h later . Similarly, splenic mononuclear cells containing NK cells were treated with interferon, before or after in vitro exposure with either halothane or isoflurane, and cytotoxicity was determined . RESULTS: In vivo, isoflurane or halothane inhibited subsequent interferon-induced NK cell stimulation (> 90% and 67%, respectively) . No inhibition occurred if interferon was given before anesthetic exposure . Significant inhibition of interferon-induced NK cell stimulation could be observed 11 days after anesthesia . In vitro, both anesthetics inhibited the subsequent stimulation of NK cytotoxicity by interferon, however, cytotoxicity of NK cells treated with interferon before anesthetic exposure was comparable to untreated interferon-stimulated NK cells . CONCLUSIONS: Halothane and isoflurane inhibit interferon stimulation of NK cytotoxicity in naive (unstimulated) NK cells of the splenic mononuclear cell pool without affecting the cytotoxicity of previously stimulated (interferon) NK cells . This could occur directly by preventing the NK cell from responding or indirectly by altering other cells in the splenic mononuclear cell pool (T cells, macrophages), which then inhibit NK cell induction. Genetics, 1993 Apr, 133(4), 775 - 84 Genetic evidence for transcriptional activation by the yeast IME1 gene product; Smith HE et al.; IME1 is required in yeast for meiosis and for expression of IME2 and other early meiotic genes . IME1 is a 360-amino acid polypeptide with central and C-terminal tyrosine-rich regions . We report here that a fusion protein composed of the lexA DNA-binding domain and IME1 activates transcription in vivo of a reporter gene containing upstream lexA binding sites . Activation by the fusion protein shares several features with natural IME1 activity: both are dependent on the RIM11 gene product; both are impaired by the same ime1 missense mutations; both are restored by intragenic suppressors . The central tyrosine-rich region is sufficient to activate transcription when fused to lexA . Deletion of this putative activation domain results in a defective IME1 derivative . Function of the deletion derivative is restored by fusion to the acidic Herpesvirus VP16 activation domain . The C-terminal tyrosine-rich region is dispensable for transcriptional activation; rather it renders activation dependent upon starvation and RIM11 . Immunofluorescence studies indicate that an IME1-lacZ fusion protein is concentrated in the nucleus . These observations are consistent with a model in which IME1 normally stimulates IME2 expression by providing a transcriptional activation domain at the IME2 5' regulatory region. Virology, 1993 Apr, 193(2), 631 - 41 Enteric adenovirus type 40: expression of E1B proteins in vitro and in vivo; Bailey A et al.; The genes encoding the enteric adenovirus type 40 E1B proteins designated 19K, 55K, and 15K (55K related) have been cloned into the pET3a expression vector and synthesized by in vitro transcription and translation and by in vivo expression after induction in bacteria . The 19K product expressed in bacteria is recognized by anti-peptide sera specific for the C-terminal region of the open reading frame and has the same M(r) as 19K protein immunoprecipitated from virus-infected cells . The 55K protein synthesized in bacteria is insoluble except under extreme denaturing conditions, but after in vitro transcription followed by translation, a polypeptide of the predicted size is obtained . The 15K protein, equivalent to the first 73 and last 29 of the 476-residue 55K protein with an internal deletion of 374 amino acids, is expressed to a high level in bacteria in a soluble form and interacts weakly but specifically with N- and C-terminal anti-peptide sera . The bacterially expressed 15K protein was used to raise antibodies in rabbits . This serum precipitates the 55K protein expressed by in vitro translation, but only the 15K product can be immunoprecipitated from virus-infected cells . The same antiserum, however, detects the 55K protein in infected cells by Western blotting, at a time broadly coinciding with the onset of DNA replication . This is the first identification of Ad40 55K protein in infected cells and confirms that the Ad40 22S mRNA can be utilized in vivo . The question of whether this protein is functional can now be addressed. Oncogene, 1993 Apr, 8(4), 823 - 31 A novel Yes-related kinase, Yrk, is expressed at elevated levels in neural and hematopoietic tissues; Sudol M et al.; While screening a chicken kidney cDNA library for the normal homolog of the yes oncogene, we isolated a clone that encodes a novel non-receptor type protein tyrosine kinase of the Src family . We named this gene product Yrk (York), as an acronym for Yes-related kinase . As predicted from the cDNA sequence, the Yrk protein consists of 536 amino acids and has all the canonical features of a Src kinase . At the amino terminus it contains a myristylation signal, followed by a unique domain, SH3 and SH2 motifs, an ATP binding site, a kinase region and a carboxy-terminal sequence with a potential regulatory tyrosine at position 530 . The sequence of the Yrk protein showed 79% identity with human Fyn and 72% identity with chicken Yes . To eliminate the possibility that the Yrk protein is an avian homolog of mammalian Fyn, we isolated and sequenced the chicken fyn cDNA . The sequence data together with Southern and Northern blot analyses showed that the chicken yrk gene is distinct from the chicken fyn gene . Antibodies generated against the unique domain of the yrk protein expressed in bacteria precipitated a 60-kDa protein that was active in an immune complex kinase assay and was phosphorylated on tyrosine . Expression of the Yrk protein in adult chicken tissues was elevated in cerebellum and spleen . Relatively high levels of Yrk were also found in lung and skin. J Immunol, 1993 Apr 1, 150(7), 2920 - 30 Macrophage phagocytosis of virulent but not attenuated strains of Mycobacterium tuberculosis is mediated by mannose receptors in addition to complement receptors; Schlesinger LS; We have examined macrophage receptors that mediate phagocytosis of virulent strains (Erdman and H37Rv) and an attenuated strain (H37Ra) of the intracellular pathogen, Mycobacterium tuberculosis . Adherence of the three strains to monocyte-derived macrophages (MDM) is markedly enhanced (>threefold) in the presence of low levels of fresh serum and requires heat-labile serum components because heat inactivation of serum reduces adherence by 65 +/- 5 to 71 +/- 2% . In the presence and absence of serum, adherence of the three strains to MDM is comparable . By electron microscopy, all bacteria are ingested and reside in phagosomes . C receptors (CR) play an important role in adherence of the three strains to MDM in the presence and absence of serum . mAb against CR1, CR3, and CR4 inhibit adherence of Erdman M . tuberculosis in fresh serum by 75 +/- 3% and inhibit the low level of adherence of Erdman (71 +/- 13%), H37Rv (72 +/- 1%), and H37Ra (64 +/- 14%) M . tuberculosis in the absence of serum . Mannose receptors (MR) play an important role in mediating macrophage adherence of the virulent strains but not the attenuated strain of M . tuberculosis . Preincubation of MDM with soluble mannan or mannose-BSA consistently and significantly inhibits adherence of Erdman and H37Rv (up to 60 +/- 7%) but not H37Ra (0 +/- 1 to 5 +/- 5% enhancement of adherence) in the absence of serum . Down-modulation of macrophage MR on mannan substrates inhibits adherence of Erdman (52 +/- 8%) and H37Rv (55 +/- 6%) but not H37Ra (2 +/- 2% enhancement of adherence) . Preincubation of MDM with soluble N-acetylglucosamine-BSA also significantly inhibits adherence of the virulent strains (42 +/- 3%) . Preincubation of MDM with glucose-BSA minimally inhibits adherence of the three strains (2 +/- 4 to 12 +/- 5%) . Anti-MR antibody inhibits adherence of Erdman (57 +/- 2%) and H37Rv (44 +/- 4%) but not H37Ra (4 +/- 5% enhancement of adherence) . Inhibition of adherence of zymosan was comparable with that seen with virulent strains of M . tuberculosis in these studies . Down-modulation of macrophage MR also inhibits adherence of Erdman (48 +/- 9%) and H37Rv (20 +/- 2%) in the presence of serum . Simultaneous blockade of MR and CR does not further inhibit adherence of the virulent M . tuberculosis strains over that seen with blocking CR alone.(ABSTRACT TRUNCATED AT 400 WORDS) Cancer Res, 1993 Apr 1, 53(7), 1620 - 4 ras mutations in 2-acetylaminofluorene-induced lung and liver tumors from C3H/HeJ and (C3H x A/J)F1 mice; Wang Y et al.; Previous studies have demonstrated mutagenic specificity of 2-acetylaminofluorene (AAF) in several strains of bacteria and mammalian cells . Examination of AAF-induced B6C3F1 mouse liver tumor DNAs indicates a G-->T (or C-->A) transversion in the H-ras gene . In the present study, 6 mouse lung tumors {2 were from C3H/HeJ mice and 4 were from (C3H x A/J)F1 mice} and 20 C3H/HeJ mouse liver tumors induced by AAF were analyzed for the presence of activating mutations in the ras gene by utilizing polymerase chain reaction, single-strand conformation polymorphism, and direct DNA sequencing analysis . All of the lung tumors contained an activated K-ras protooncogene with an A-->T transversion at the second base of codon 61 . The activating mutations in the H-ras gene were detected in 14 of 20 AAF-induced mouse liver tumors with 13 of 14 having a C-->A transversion at the first base of codon 61 and 1 of 14 having an A-->T transversion at the second base of codon 61 . The selectivity of mutations in the ras oncogene observed in AAF-induced mouse lung and liver tumors, as compared to those in spontaneously occurring mouse lung and liver tumors, suggests that AAF may directly induce point mutations in the ras gene . The difference in the ras mutation spectra between lung and liver tumors induced by AAF indicates that AAF mutagenesis could be tissue-specific. Microb Pathog, 1993 Apr, 14(4), 253 - 60 The adenylate cyclase toxin contributes to the survival of Bordetella pertussis within human macrophages; Masure HR; The adenylate cyclase toxin (ACT) of Bordetella pertussis has been shown to penetrate eucaryotic cells and produce a rapid elevation in intracellular cAMP which leads to altered cell function . Recent studies have demonstrated an intracellular state for the bacteria within professional and non-professional phagocytes . A virulent strain was compared to two ACT defective strains to determine if this toxin contributes to intracellular survival within human macrophages . When challenged by 10(6) macrophages/ml in a cell invasion assay, 10(3) bacteria/ml were recovered from samples containing the ACT defective strains . These values were two log units less than the number of bacteria recovered from samples containing the isogenic parent . The binding and uptake of all strains by the macrophages were equivalent, suggesting that ACT does not affect adhesion nor endocytosis but rather protects against macrophage killing following uptake . Drug-induced elevation of cAMP levels within the macrophage by forskolin increased the number of surviving bacteria in samples containing the mutant strains to values equal to those obtained with the parent strain . Therefore, the protective effect conveyed by ACT is the result of toxin-induced elevation of cAMP within the macrophage concomitant with bacterial uptake. J Gen Virol, 1993 Apr, 74 ( Pt 4), 733 - 40 Computer-assisted identification of a putative methyltransferase domain in NS5 protein of flaviviruses and lambda 2 protein of reovirus; Koonin EV; A sequence motif that is conserved in a number of S-adenosylmethionine (SAM)-utilizing methyltransferases and is implicated in SAM binding was identified in the N-terminal portion of NS5 proteins of flaviviruses and in lambda 2 protein of reovirus . An additional conserved motif was shared by these viral proteins and two distinct groups of methyltransferases including as the prototypes Rhodobacter capsulatus hydroxyneurosporene methylase (crtF gene product) and yeast 3,4-dihydroxy-5-hexaprenylbenzoate methylase (COQ3 gene product), respectively . Statistically significant similarity was revealed between the region of flavivirus NS5 containing the SAM-binding motif and a newly characterized family of putative methyltransferases from bacteria, yeast and plants, which is related to the Coq3 group . Amino acid sequence signatures were derived that are unique for NS5 proteins and different subsets of (putative) cellular methyltransferases . It is hypothesized that the N-terminal domain of NS5 is a methyltransferase involved in viral RNA capping . Thus NS5 may be a two-domain protein, with its C-terminal domain comprising the RNA-dependent RNA polymerase . The putative methyltransferase domain of flaviviruses is unrelated to the methyltransferase domain previously characterized in positive-strand RNA viruses of the alphavirus-like supergroup . The lack of sequence similarity and different location of the putative methyltransferase domain underscores the drastic difference in the genome layout of flaviviruses and alphaviruses . The identification of the putative methyltransferase domain in reovirus lambda 2 protein is compatible with the available evidence that this protein is the viral capping enzyme. Rinsho Shinkeigaku, 1993 Apr, 33(4), 462 - 4 {Fungal meningitis caused by a Malassezia species masquerading as painful ophthalmoplegia}; Aoba S et al.; The patient, an otherwise healthy 42-year-old woman, developed non-throbbing periorbital pain and abducens nerve palsy of the right side two weeks prior to the present admission . Under the diagnosis of Tolosa-Hunt syndrome, she had been placed on prednisolone (30 mg/day) in another hospital, leading to exacerbation of her neurologic manifestations . On admission, neurologic examination revealed bilateral abducens nerve palsy, incomplete bilateral oculomotor paresis, and hypalgesia in the first and the second branch of the left trigeminal nerve . On CSF examination there were 742/mm3 white blood cells of which about 80% of the cells were neutrophils . The glucose was 70 mg/dl (blood glucose was 170 mg/dl) and the protein 49 mg/dl . Although repeated cultures for bacteria or fungi were negative, PAS stains for CSF sediments showed a large number of yeasts morphologically consistent with a Malassezia species . Anti-fungal treatment with fluconazole and flucytosine resulted in dramatic improvement both in neurologic signs and laboratory findings . According to morphological criteria, the yeasts found in CSF sediments from this patient differed from those described previously as being pathogenetic in the CNS fungal infection . By contrast, these yeasts were similar to a Malassezia species in all aspects . Because some Malassezia requires oil for its growth in culture, it is possible that it failed to grow in the standard media and thus escaped recognition. J Forensic Sci Soc, 1993 Apr-Jun, 33(2), 87 - 94 Differentiation of alpha-amylase from various sources: an approach using selective inhibitors; Quarino L et al.; A radial diffusion assay in an agarose/starch gel utilizing crude kidney bean extract and a commercially prepared alpha-amylase inhibitor isolated from wheat seeds was developed and assessed to determine its ability to differentiate alpha-amylase from various sources . Kidney bean extract was found to have a greater inhibitory effect on AMY2, while the wheat lectin inhibitor was found to have a greater inhibitory effect on AMY1 . Neither inhibitor was found to have any effect on commercially prepared bacterial alpha-amylase extract in both liquid preparations and dried stains . Mixtures of varying concentrations of pancreatic and salivary extracts also gave interpretable results . Additionally, dried stains prepared from human body fluids having high levels of AMY2 were differentiated from dried stains prepared from human body fluids containing high levels of AMY1. Intern Med, 1993 Apr, 32(4), 350 - 4 Treatment of ulcerative colitis with camostat mesilate, a serine protease inhibitor; Senda S et al.; We were able to induce and maintain remission with camostat mesilate, a serine protease inhibitor, in two patients with ulcerative colitis, to whom salicylazosulfapyridine could not be administered due to previous side effects . The enzymatic activity of proteases from granulocyte, pancreatic juice and bacteria is possibly harmful to the inflamed colonic mucosa . Camostat mesilate can be expected to have an anti-inflammatory effect on the damaged mucosa of inflammatory bowel disease. Zentralbl Bakteriol, 1993 Apr, 278(2-3), 177 - 86 Differential regulation of Bordetella pertussis virulence factors; Gross R et al.; Bordetella pertussis, the causative agent of whooping cough, regulates its virulence factors coordinately according to environmental parameters such as temperature and certain chemicals . A regulatory locus has been characterized which is essential for this regulation . This bvg locus codes for a two-component regulatory system composed of the sensor protein BvgS and the transcriptional activator protein BvgA . It has been shown that the BvgA and BvgS proteins are sufficient for the transcriptional regulation of some virulence factors such as the filamentous haemagglutinin (FHA) involved in adhesion . The recent identification of new regulatory mutants demonstrates that the regulation of some virulence factors such as the pertussis toxin (PTX) and the adenylate cyclase toxin (CYA) is more complex and involves additional regulatory factor(s) . This finding suggests that the regulation of the various virulence factors is coordinated at the highest level of regulation, but there may be differences in the fine regulation of some of the factors such as the adhesins and the toxins. J Am Dent Assoc, 1993 Apr, 124(4), 77 - 80 Possibility of cross-contamination between dental patients by means of the saliva ejector; Watson CM et al.; Concern about cross-contamination between dental patients prompted investigation of current suctioning practices . The possibility of the suck-back phenomenon and the presence of oral bacteria in vacuum lines were studied, and dental offices were surveyed concerning the use and disinfection of suction equipment. Tuber Lung Dis, 1993 Apr, 74(2), 74 - 86 Respiratory disorders in agriculture; Zejda JE et al.; Work in agriculture is associated with exposure to respiratory biohazards . The most important airborne substances include grain dust and its constituents, bacteria and metabolites (endotoxin), fungi and metabolites (glucan), and storage mites . The degree of dysfunction in exposed persons depends on the biological potency and concentration of exposure as well as on individual susceptibility . Airborne contaminants frequently occur in concentrations and compositions that challenge the defence mechanisms of the lung . This may be of particular importance in the case of susceptible workers and minors, whose exposure by the virtue of family-type operations is difficult to avoid . Epidemiological and clinical studies have contributed to the identification of associations between respiratory disorders and agricultural exposures . Chronic bronchitis, asthma, hypersensitivity pneumonitis, organic dust toxic syndrome and chronic airflow limitation have been found to occur in agricultural workers . Clinical and experimental studies have advanced the understanding of immunologic and non-immunologic mechanisms involved in respiratory responses to a wide spectrum of inhaled organic dusts . Although the evidence has provided substantial insight into the occurrence and pathogenesis of respiratory disorders in agriculture, further investigation is necessary . There is a need for research involving accurate assessment of exposures and their respiratory effects . There is also a need for the establishment of preventive programs, with emphasis on reduction of harmful exposures . Increasing concern about respiratory disorders in agriculture justifies further scientific effort in both areas. Mol Cell Probes, 1993 Apr, 7(2), 133 - 8 Development of monoclonal antibodies for the detection of Mycoplasma pneumoniae; Geary SJ et al.; Mycoplasma pneumoniae-specific monoclonal antibodies were constructed for the purpose of developing reagents for clinical diagnostics . The monoclonal antibodies, designated Mp2B12 and Mp3A11, recognize surface exposed antigens of 28 kDa and 170 kDa, respectively . Mp3A11 recognizes an epitope on a cytadhesin molecule, P1, which is not shared on the analogous cytadhesin of M . genitalium . Both monoclonal antibodies are capable of detecting 1 x 10(5) M . pneumoniae in a standard ELISA test. Microsc Res Tech, 1993 Apr 1, 24(5), 400 - 22 Impact of freeze substitution on biological electron microscopy; Hippe-Sanwald S; Considering the increasing necessity for improved preparation techniques in biological electron microscopy as a basis for the identification and localization of cellular substances within the compartments of the cell, this review is focussed on the method of freeze substitution as an important link between the cryofixation (ultrarapid freezing) and resin embedding of biological specimens . The theory and practice of freeze substitution is summarized with particular interest in the physical and thermodynamic as well as in the chemical basis of this technique . A survey of practical aspects of the technical process of freeze substitution concerning the equipment and various protocols successfully applied in biological systems is also given . The main advantage of freeze substitution versus conventional chemical fixation is seen in the maintenance of the hydration shell of molecules and macromolecular structures . This results in an improved fine structural preservation, superior retention of the antigenicity of proteins and decreased loss of unbound, diffusible cellular components . Examples of excellent visualization of the ultrastructure of macromolecular complexes (nucleic acids, extracellular material, membranes etc.), small organisms (bacteria, algae, cyanobacteria and fungi) and large biological samples such as plant and animal tissue as well as the plant-pathogen (fungus) interface and infection structures are presented . Recent data on the molecular characterization of freeze-substituted biological tissue are exemplified with special emphasis on the subcellular detection of soluble components (elements, lipids, proteins and drugs) and the inter-/intracellular localization of proteins including foreign proteins in transgenic plants . The molecular analysis of freeze-substituted specimens is achieved by the combination of low temperature preparation techniques in biological electron microscopy with various detection methods such as X-ray microanalysis, immunocytochemistry and high resolution autoradiography. Semin Cell Biol, 1993 Apr, 4(2), 87 - 92 On plant growth regulators and their metabolites: a changing perspective; Palme K et al.; From seed germination to vegetative growth and flowering virtually all aspects of plant growth and development are influenced by structurally relatively simple substances, termed phytohormones . It has been argued that the wide range of responses elicited by these substances requires a mode of action that is radically different from those of animal hormones . In contrast to animal hormones, it is often very difficult to distinguish between the site of synthesis and the site of action of phytohormones . Hence, plants may have developed their own mechanisms for synthesis, sequestration and release of active hormones . Current evidence indicates that enzymes that can synthesize and modify phytohormones and their antagonists or hydrolyze phytohormone conjugates to release active hormones which play a role in initiating important regulatory pathways . They are also likely to provide invaluable tools for studying the mechanisms underlying growth and development in plants. Kansenshogaku Zasshi, 1993 Apr, 67(4), 299 - 304 {Detection of Chlamydia pneumoniae by polymerase chain reaction}; Kawayama T et al.; We aimed at developing a method for early detection of Chlamydia pneumoniae (C . pneumoniae) from clinical specimens . For this purpose, we amplified C . pneumoniae-specific DNA fragments by polymerase chain reaction . A pair of 24 mer of oligonucleotides which were complementary to the sequences within the region encoding the major outer membrane were synthesized and used as primers . As the results, all three standard strains of C . pneumoniae (AR-39, TW-183 and AR-388) were identified by the detection of the amplified products of 174 base pairs, while each strain of Chlamydia trachomatis and Chlamydia psittaci and a total of 11 strains of bacteria and a strain of Mycoplasma pneumoniae were not . Thus, the present method was found to provide a very high specificity and also a high sensitivity of a detectable level of 10 x 10(-9) inclusion-forming units. Plant J, 1993 Apr, 3(4), 573 - 85 Characterization of GmENOD40, a gene showing novel patterns of cell-specific expression during soybean nodule development; Yang WC et al.; In this paper, the soybean 'early nodulin' clone pGmENOD40 is characterized . The GmENOD40 encoded protein does not contain methionine and does not show homology to proteins identified so far . In situ hybridizations showed that this gene has a complex expression pattern during development of determinate soybean nodules . At early stages of development transcription is induced in dividing root cortical cells, the nodule primordium and the pericycle of the root vascular bundle . In mature soybean nodules, the gene is expressed in the uninfected cells of the central tissue and in the pericycle of the nodule vascular bundles . Studies on nodules devoid of intracellular bacteria and infection threads, showed that the expression of the gene in the nodule primordium is induced in these empty nodules, while the induction of the GmENOD40 gene in the nodule vascular bundle requires the presence of intracellular bacteria or infection threads . A pea cDNA clone homologous to GmENOD40 was isolated to enable in situ hybridization studies on indeterminate nodules . The expression patterns in both determinate and indeterminate nodules suggests that the ENOD40 protein might have a transport function. Rev Latinoam Microbiol, 1993 Apr-Jun, 35(2), 143 - 6 {Mycoplasma sp . in the respiratory tract of hospitalized children}; Garcia-Ramos E et al.; Mycoplasma pneumoniae is one of the most common bacteria causing respiratory diseases in other countries, specially in older children, adolescents and young adults and less frequently in the age group studied here, nevertheless the determination of its presence in this group was considered important . Two hundred and fifty throat swabs were taken from children, under five years of age, hospitalized with a diagnosis of acute respiratory infections (ARI) and to 50 children, same age, with no ARI (controls) . The samples were placed in transport media and were incubated at 37 degrees C during 7 to 15 days . They were reinoculated in PPLO agar and typical colonies were looked for, 5 to 8 days later . The organisms were identified by biochemical tests . Eight Mycoplasma sp (3.2%) were obtained, five of them were M . pneumoniae (2.0%) and three M . hominis (1.2%) . Only in 2 cases adenoviruses with M . hominis were found in the absence of other pathogens . It was shown that M . pneumoniae also infects children under five years old, so its present should be suspected, specially when the patient's health does not improve with the installed treatment . Some important suggestions for the isolation of mycoplasma are given. Cell Growth Differ, 1993 Apr, 4(4), 281 - 9 Structure and DNA-binding properties of Pax-QNR, a paired box- and homeobox-containing gene; Dozier C et al.; After differential screening of a complementary DNA library constructed from quail neuroretina cells (QNR) infected with the v-myc-containing avian retrovirus MC29, we have isolated a complementary DNA clone which identifies a mRNA essentially expressed in the neuronal layer of the retina . This complementary DNA encodes a protein containing paired box and homeobox domains . This gene, called Pax-QNR, is homologous to the murine Pax-6 and human AN genes, which are mutated in the autosomal dominant mutation small eye (Sey) of the mouse and aniridia in humans . Here, we report the genomic exon-intron organization, as well as the existence of alternative splicing events taking place at both the 5' end and the middle part of the gene . A Pax-QNR clone translated in reticulocyte lysate directed the synthesis of a 46 kilodalton protein able to bind specifically to the e5 sequence present upstream of the Drosophila even-skipped gene and target of the Drosophila paired protein . The Pax-QNR paired and homeobox domains individually expressed in bacteria are both able to recognize the e5 sequence. Curr Opin Biotechnol, 1993 Apr, 4(2), 211 - 6 Modelling and analysis of metabolic pathways; Liao JC; Modelling and analysis of metabolic pathways has received an increasing amount of attention over the past few years . Progress has been made in many aspects such as the identification of rate-controlling steps, applications of optimization principles, and stoichiometric analyses . In addition, the scope of modelling has also expanded . These efforts have led to an improved understanding of metabolic pathways and have facilitated their manipulation. Zhonghua Yi Xue Za Zhi, 1993 Apr, 73(4), 226 - 8, 254 {ELISA test for granulocyte colony stimulating factor using monoclonal antibody and its clinical results}; Li TS; Granulocyte colony stimulating factor (G-CSF) level in the serum rises within minutes after people infected by bacteria . It can reach almost 1,000 fold above normal level . We established an ELISA test for measuring G-CSF using McAb . After injected with endotoxin into mice, this method was used to observe the peak serum G-CSF in mouse . Again 200 normal people were tested on G-CSF, but all showed negative results . In 100 bacteria-infected patients, 82 (82%) showed positive results . In 100 non-bacteria-infected patients with fever, only 7(7%) was positive . It is indicated that testing body fluids and serum can determine whether the patient is infected with bacteria or not. Immun Infekt, 1993 Apr, 21(2), 36 - 40 {The endotoxin receptor CD14}; Schutt C et al.; The knowledge about molecular mechanisms of endotoxin (LPS) recognition by cellular receptor CD14 and its consequences as well as the relationship between soluble and membrane-bound receptor is reviewed . The binding of endotoxins to membrane-bound CD14 is mediated by special so-called LPS-binding serum proteins . The mechanism of signal transduction is not yet known . After activation by LPS, monocytes produce free oxygen radicals, IL-1, IL-6, TNF alpha and other mediators . CD14 is present in normal serum as soluble receptor which can neutralize endotoxins in respect to their monocyte activating capacity. Am J Med Sci, 1993 Apr, 305(4), 248 - 73 Southwestern Internal Medicine Conference: clinical use of hematopoietic growth factors; Fleischman RA; The hematopoietic growth factors, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF), have been cloned, produced in bacteria and yeast, and approved for clinical use in the treatment of neutropenia . Both factors stimulate the proliferation and maturation of neutrophil progenitors and enhance the effector functions of mature cells by interaction with specific receptors on the cell surface . Serum levels of G-CSF correlate inversely with the neutrophil count, suggesting that G-CSF may be the normal homeostatic regulator of the neutrophil count, while GM-CSF is generally undetectable in the serum and appears under normal physiologic conditions to act locally at inflammatory sites . Phase I and II clinical trials with these factors demonstrated minimal toxicity for G-CSF and mild to moderate dose-dependent toxicity for GM-CSF . Recent clinical trials, including double-blind, randomized studies, support a role for these growth factors in the treatment of chronic neutropenias, such as Kostmann's syndrome, acquired immune deficiency syndrome (AIDS), aplastic anemia, and myelodysplasia, as well as in acute neutropenias, such as cyclic neutropenia, chemotherapy-induced neutropenia, and bone marrow transplantation. J Med Microbiol, 1993 Apr, 38(4), 278 - 85 Intracellular persistence of chlamydial major outer-membrane protein, lipopolysaccharide and ribosomal RNA after non-productive infection of human monocytes with Chlamydia trachomatis serovar K; Schmitz E et al.; The replication of Chlamydia trachomatis serovar K was studied in human peripheral blood monocytes (PBMo) . The intracellular fate of the bacteria was examined by determining the presence of chlamydial major outer-membrane protein (MOMP), lipopolysaccharide (LPS) and ribosomal RNA (rRNA) . In-vitro infection of PBMo with C . trachomatis serovar K was not productive . However, chlamydial MOMP antigen, demonstrated by immunofluorescence, was present in PBMo for up to 14 days . Infected monocytes also contained chlamydial rRNA, measured by in-vitro hybridisation, and LPS, measured by enzyme immunoassay, for up to 14 days . These data are compatible with the hypothesis that the infection of PBMo with C . trachomatis may play a role in the systemic distribution of chlamydial antigens, leading to systemic manifestations of urogenital chlamydial infection. J Med Microbiol, 1993 Apr, 38(4), 240 - 4 Affinity of the gastric pathogen Helicobacter pylori for the N-sulphated glycosaminoglycan heparan sulphate; Ascencio F et al.; Binding of 125I-heparan sulphate was a common property of Helicobacter pylori strains isolated from patients with gastroduodenal ulcer diseases . Binding was (i) saturable; (ii) reversible by the addition of unlabelled heparan sulphate and heparin; (iii) inhibited by unlabelled heparan sulphate, heparin, and heparin oligosaccharides but not by other glycosaminoglycans of comparable size (chondroitin sulphate and dermatan sulphate) or by highly glycosylated glycoproteins (hog gastric mucin and fetuin); (iv) reduced by heat treatment (80 degrees C, 10 min) and exposure of the bacteria to pronase E, proteinase K, trypsin and chymotrypsin, but unaffected by treatment with pepsin and neuraminidase; and (v) time-, pH-, and ionic strength-dependent . Scatchard plot analysis of the binding data indicated the presence of one class of high-affinity receptor (Kd = 9 x 10(-9) M) for heparan sulphate. J Virol, 1993 Apr, 67(4), 2235 - 44 Novel monoclonal antibodies that differentiate between the binding of pp60c-src or protein phosphatase 2A by polyomavirus middle T antigen; Dilworth SM et al.; Fourteen pGEX plasmids that express defined regions of polyomavirus middle T antigen in bacteria have been constructed . These polypeptides have been used to generate 18 new monoclonal antibodies directed against the unique portion of middle T and to map the approximate position of the antibody recognition sites onto the protein sequence . All of the antibodies effectively immunoprecipitate middle T and the associated 60- and 35-kDa components of protein phosphatase 2A . Four of the antibodies, however, do not react with middle T when it is bound to pp60c-src . These four probably bind to amino acids 203 to 218 of the middle T protein sequence, which are encoded by the mRNA immediately 3' to the splice junction that creates the C-terminal unique region . This suggests that additional middle T sequences are required for middle T's interaction with pp60c-src than are needed for its binding to protein phosphatase 2A . The antibodies localize this extra region and provide a means of distinguishing between these two associations. Gene, 1993 Mar 30, 125(2), 199 - 204 Hidden domains and active site residues in beta-glycanase-encoding gene sequences? Henrissat B. Reading-frame corrective shifts in the nucleotide sequence upstream, within, or downstream from the putative coding region of several beta-glycanase-encoding genes reported in the literature reveal hidden active-site residues or even additional domains, including a cellulose-binding domain on a beta-mannanase-encoding gene . These findings also help in assigning, to cellulase family A, two enzymes previously found to lack sequence similarity with known cellulase families. Commun Dis Rep CDR Rev, 1993 Mar 26, 3(4), R59 - 62 Clinical aspects of infection with Helicobacter pylori; Bell GD; About 90% of patients with duodenal ulcer and 65% of those with gastric ulcer are infected with Helicobacter pylori . H . pylori infection can be diagnosed by examination of biopsy material obtained at endoscopy; by 14C or 13C-urea breath tests, or by serological means . The relapse rate of duodenal and gastric ulcers can be considerably reduced if the bacteria are eradicated . Some of the current treatment regimens are discussed. Biochim Biophys Acta, 1993 Mar 20, 1172(3), 262 - 6 Effect of a rare leucine codon, TTA, on expression of a foreign gene in Streptomyces lividans; Ueda Y et al.; Streptomyces are bacteria with a very high chromosomal G+C composition (> 70 mol%) and extremely biased codon usage . In order to investigate the relationship between codon usage and gene expression in Streptomyces, we used ssi (Streptomyces subtilisin inhibitor) as a reporter gene and monitored its secretory expression in S . lividans . In consequence of alteration of the native codons of Leu, Lys and Ser of ssi to minor ones by site-directed mutagenesis, i.e., Leu79-Leu80: CTG-CTC to TTA-TTA, Lys89: AAG to AAA, Ser108-Ser109: TCG-AGC to TCT-TCT, respectively, the production of SSI was reduced remarkably in the case of TTA codons, while it was slightly increased in the case of AAA and almost the same in TCT codons . This conspicuous decrease found for Leu codon replacement was probably due to the low availability of intracellular tRNA(Leu) (UUA), a product of bldA which has been reported to be expressed only during the late stage of growth. Ugeskr Laeger, 1993 Mar 15, 155(11), 775 - 8 {Acne vulgaris}; Rossen MH et al.; Acne vulgaris is one of the most common dermatological diseases . The prevalence may be as high as 83-95% at age 16, but decreases at age 20, and is very low at age 35 . The aetiology and pathogenesis are not completely known, but the following factors are involved: 1) increased sebum secretion, 2) follicular keratinisation, 3) bacteria and 4) inflammation . Furthermore, genetic and exogenic factors play a role . Acne can be divided into 5 groups depending on its severity . Treatment principles within these 5 groups are reviewed . Treatment can not be expected to take effect before 1-2 months have passed, but all patients can be cured with the right treatment . The effects and side effects of the various treatments are described . Treatment with isotretinoin should only be initiated by dermatologists. Rev Prat, 1993 Mar 15, 43(6), 667 - 72 {Physiopathology and principles of intensive care in intestinal obstructions}; Millat B et al.; The physiopathology of intestinal obstruction consists of increased intestinal peristaltis, distension by gas and fluids, contraction of the extracellular fluid volumes (plasma and interstitial sectors) and bacterial proliferation . To this must be added, in obstruction by strangulation, the passage of bacteria and bacterial products into the general circulation and the peritoneal cavity through an ischaemic or necrotic intestinal wall . Metabolic disorders consist of water, sodium and potassium deficits and acid-base disturbances . Water and electrolyte replacement should take into account the deficits that existed at the beginning of treatment, the additional losses expected during treatment and the needs for daily maintenance of water and electrolyte balance . The therapeutic procedure is simple provided it is systematized. Proc Natl Acad Sci U S A, 1993 Mar 15, 90(6), 2150 - 4 Brain contains two forms of synaptic vesicle protein 2; Bajjalieh SM et al.; Molecular cloning of a cDNA encoding synaptic vesicle protein 2 (SV2) revealed that it is homologous to a family of proton cotransporters from bacteria and fungi and to a related family of glucose transporters found in mammals . The similarity to proton cotransporters raised the possibility that SV2 might mediate the uptake of neurotransmitters into vesicles, an activity known to require a proton gradient . To determine whether SV2 is a member of a family of vesicular proteins, we used the SV2 clone to screen for similar cDNAs in rat brain . We characterized 42 clones, 25 of which encode SV2 and 4 of which encode a protein, SV2B, that is 65% identical and 78% similar to SV2 . The protein encoded by SV2B cDNA is recognized by the monoclonal antibody that defines the SV2 protein . When SV2B is expressed in COS cells, antibody labeling is reticular in nature, suggesting that SV2B, like SV2 (hence, SV2A), is segregated to intracellular membranes . The expression of SV2B is limited to neural tissue . While both forms of SV2 are expressed in all brain regions, SV2B is expressed at highest levels in the cortex and hippocampus, whereas the highest level of expression of SV2A is in subcortical regions . Therefore, the SV2 proteins, like other characterized synaptic vesicle proteins, comprise a small gene family. Science, 1993 Mar 12, 259(5101), 1622 - 5 Effect of PU.1 phosphorylation on interaction with NF-EM5 and transcriptional activation; Pongubala JM et al.; PU.1 recruits the binding of a second B cell-restricted nuclear factor, NF-EM5, to a DNA site in the immunoglobulin kappa 3' enhancer . DNA binding by NF-EM5 requires a protein-protein interaction with PU.1 and specific DNA contacts . Dephosphorylated PU.1 bound to DNA but did not interact with NF-EM5 . Analysis of serine-to-alanine mutations in PU.1 indicated that serine 148 (Ser148) is required for protein-protein interaction . PU.1 produced in bacteria did not interact with NF-EM5 . Phosphorylation of bacterially produced PU.1 by purified casein kinase II modified it to a form that interacted with NF-EM5 and that recruited NF-EM5 to bind to DNA . Phosphopeptide analysis of bacterially produced PU.1 suggested that Ser148 is phosphorylated by casein kinase II . This site is also phosphorylated in vivo . Expression of wild-type PU.1 increased expression of a reporter construct containing the PU.1 and NF-EM5 binding sites nearly sixfold, whereas the Ser148 mutant form only weakly activated transcription . These results demonstrate that phosphorylation of PU.1 at Ser148 is necessary for interaction with NF-EM5 and suggest that this phosphorylation can regulate transcriptional activity. Nucleic Acids Res, 1993 Mar 11, 21(5), 1251 - 7 Prediction of common folding structures of homologous RNAs; Han K et al.; We have developed an algorithm and a computer program for simultaneously folding homologous RNA sequences . Given an alignment of M homologous sequences of length N, the program performs phylogenetic comparative analysis and predicts a common secondary structure conserved in the sequences . When the structure is not uniquely determined, it infers multiple structures which appear most plausible . This method is superior to energy minimization methods in the sense that it is not sensitive to point mutation of a sequence . It is also superior to usual phylogenetic comparative methods in that it does not require manual scrutiny for covariation or secondary structures . The most plausible 1-5 structures are produced in O(MN2 + N3) time and O(N2) space, which are the same requirements as those of widely used dynamic programs based on energy minimization for folding a single sequence . This is the first algorithm probably practical both in terms of time and space for finding secondary structures of homologous RNA sequences . The algorithm has been implemented in C on a Sun SparcStation, and has been verified by testing on tRNAs, 5S rRNAs, 16S rRNAs, TAR RNAs of human immunodeficiency virus type 1 (HIV-1), and RRE RNAs of HIV-1 . We have also applied the program to cis-acting packaging sequences of HIV-1, for which no generally accepted structures yet exist, and propose potentially stable structures . Simulation of the program with random sequences with the same base composition and the same degree of similarity as the above sequences shows that structures common to homologous sequences are very unlikely to occur by chance in random sequences. J Biol Chem, 1993 Mar 5, 268(7), 5097 - 106 Regulation and properties of extracellular signal-regulated protein kinases 1 and 2 in vitro; Robbins DJ et al.; Extracellular signal-regulated protein kinases (ERK) 1 and 2 and mutants of each were expressed in bacteria with a hexahistidine tag and purified using nickel-chelate chromatography . Basal activity of wild type ERK2 was approximately 2 nmol/min/mg . Self-catalyzed phosphorylation occurred in vitro on the major physiological site of tyrosine phosphorylation in an intramolecular reaction . Rabbit muscle ERK activator activated ERK2 500-1000-fold up to a specific activity (approximately 2 mumol/min/mg) approximating that of ERK1 purified from stimulated cells (Boulton, T.G., Gregory, J.S., and Cobb, M.H . (1991) Biochemistry 30, 278-286) . ERK1 could also be activated by the ERK activator to the same extent . Mutants lacking the major site of tyrosine phosphorylation were autophosphorylated at a greatly reduced rate and were no longer highly activated by the ERK kinase . Mutants lacking the major site of threonine phosphorylation were autophosphorylated at the same or an enhanced rate, but the kinase activity of these mutants depended on the residue used to replace the threonine . Replacement by glutamate rendered the kinase capable of being activated by ERK activator, while replacement by alanine did not . Thus, the carboxyl group of glutamate can provide at least some of the features introduced by phosphothreonine in activated ERKs. J Biol Chem, 1993 Mar 5, 268(7), 5131 - 8 Structural and functional studies on the G(o) protein; van der Voorn L et al.; Monoclonal antibodies were raised against purified bovine and human brain G-proteins . The epitopes recognized by three monoclonal antibodies (MONO, 3C2, and 3E7) were mapped by expressing defined parts of the bovine G(o) alpha-cDNA in bacteria, followed by immunoblotting . All three antibodies recognize the recombinant bovine alpha o-protein, but at distinct sites . The epitopes of MONO and 3C2 were mapped between alpha o amino acids 80 and 145, and both antibodies recognize alpha o exclusively . Heterotrimeric G(o)-proteins as well as guanosine 5'-3-O-(thio)triphosphate-liganded free alpha o-subunits are readily immunoprecipitated by these monoclonal antibodies . Binding of MONO or 3C2 does not affect ADP-ribosylation of the alpha o-subunit by pertussis toxin . Apparently, the antibodies do not bind to or induce large conformational changes in regions of the alpha o-subunit that are involved in association with beta gamma-subunits or ADP-ribosylation . 3E7 behaves as an anti common alpha-subunit antibody when used in immunoblots . However, under nondenaturing conditions, 3E7 recognizes alpha o exclusively . After binding of 3E7, the pertussis toxin-dependent ADP-ribosylation of alpha o is effectively blocked, while the ADP-ribosylation of the various alpha i-subunits is not affected . The epitope of 3E7 was mapped between alpha o amino acids 13-88, a region which has been implicated in the interaction between alpha- and beta gamma-subunits . Possibly, the inhibitory effect of 3E7 on ADP-ribosylation of G(o) is secondary to the loss of beta gamma-subunits that is observed upon binding of 3E7. Biochemistry, 1993 Mar 2, 32(8), 1958 - 64 Evidence that serine L223 is involved in the proton transfer pathway to QB in the photosynthetic reaction center of Rhodopseudomonas viridis; Leibl W et al.; In the reaction center of purple photosynthetic bacteria, the reducing equivalents produced by primary charge separation are exported via an ubiquinone molecule working as a two-electron shuttle . This loosely-bound quinone, called QB, accepts in successive flashes two electrons from the tightly bound primary quinone acceptor QA, along with two protons from the external medium . The surrounding protein plays an important role in stabilizing the semiquinone anion and in providing a pathway for protons from the cytoplasmic phase to QB . Herbicides of the triazine type compete with QB for the binding pocket and their binding is controlled by nearby amino acid residues . We have studied the kinetics of the first and second electron transfer from QA to QB in two herbicide-resistant mutants from Rhodopseudomonas viridis, T1 (ArgL217-->His,Ser L223-->Ala) and MAV5 (Arg L217-->His, Val L220-->Leu), in order to determine whether these residues are involved in proton transfer to the reduced QB . The main effect of the mutant T1 was a drastic (600-fold at pH 7) decrease in the rate of the second electron transfer to QB compared to the wild type . In contrast, the rate of the second electron transfer in the mutant MAV5 was decreased only slightly (10-fold) in the pH range from 7 to 11 . We attribute the inhibition of the second electron transfer in the Ser L223-->Ala mutation to an essential role of Ser L223 in the donation of the first proton to the reduced QB.(ABSTRACT TRUNCATED AT 250 WORDS) Eur J Epidemiol, 1993 Mar, 9(2), 213 - 6 A survey of Q-fever in Sweden; Macellaro A et al.; Coxiella burnetii, the etiological agent of Q-fever has recently been isolated from sheep in southern Sweden . In this region 24-30% of sheep farmers have been exposed to the organism as shown by serological measurements . In veterinarians, another group with high risk of exposure to C . burnetii, about 12% have antibodies to the bacteria . The seropositive veterinarians are scattered all over the country . In two non-risk groups, draftees and hospital employees, 5-7% were found to be positive . This survey showed that Q-fever is a domestic disease which is spread throughout Sweden. G Chir, 1993 Mar, 14(3), 165 - 9 {Infection of the vascular prosthesis . The diagnostic, preventive and treatment protocols: preliminary results}; Battisti G et al.; A number of strategies for the management of vascular graft infections are described in literature . Nevertheless, this serious compliance is still burdened with high rates of morbidity and mortality . At the present the principal efforts are therefore directed towards prevention and early diagnosis . In this view, the authors propose their protocol of study, on the basis of the encouraging results till now obtained. J Am Soc Nephrol, 1993 Mar, 3(9), 1541 - 54 Infectious morbidity and defects of phagocytic function in end-stage renal disease: a review; Vanholder R et al.; Infectious diseases remain among the most morbid events and are an important cause of death in ESRD . These events are related to an acquired immunodeficiency that progresses during the development of uremic retention, as part of the broader spectrum, displayed by the "uremic syndrome" . A central role in the hose defense against bacterial infection is played by the phagocytic polymorphonuclear white blood cells, which are characterized by the capacity to ingest bacteria (phagocytosis), which is followed by the destruction of those bacteria (killing capacity) . This article reviews the mechanisms of development and the potential causes that have been held responsible for this aspect of the defective immune function . The observed changes are attributed to alterations in receptor expression, although more convincing evidence points in the direction of metabolic functional disturbances, especially in the NAD(P)H-oxidase-dependent production of oxygen free radicals . The most important causative factors are: uremic toxicity, iron overload, renal anemia, dialyzer bioincompatibility, and the type of renal replacement therapy . It is concluded that the phagocytic defect in ESRD is multifactorial and that each factor should be managed by specific therapeutic approaches. Plant Mol Biol, 1993 Mar, 21(6), 1201 - 5 Nitrite reductase gene from Synechococcus sp . PCC 7942: homology between cyanobacterial and higher-plant nitrite reductases; Luque I et al.; The gene encoding nitrite reductase (nir) from the cyanobacterium Synechococcus sp . PCC 7942 has been identified and sequenced . This gene comprises 1536 nucleotides and would encode a polypeptide of 56,506 Da that shows similarity to nitrite reductase from higher plants and to the sulfite reductase hemoprotein from enteric bacteria . Identities found at positions corresponding to those amino acids which in the above-mentioned proteins hold the Fe4S4-siroheme active center suggest that nitrite reductase from Synechococcus bears an active site much alike that present in those reductases . The fact that the Synechococcus and higher-plant nitrite reductases are homologous proteins gives support to the endosymbiont theory for the origin of chloroplasts. Cesk Epidemiol Mikrobiol Imunol, 1993 Mar, 42(1), 22 - 4 {IgG antibodies to Gastrospirillum hominis and Helicobacter pylori}; Kubonova K et al.; In conjunction with an investigation extending over several years, focused on the understanding of the importance of Helicobacter pylori in inflammatory gastric disease, the authors examined a group of 1242 patients . In fifteen they detected by microscopic examination the presence of helical bacteria described in the literature as Gastrospirillum hominis . The cultivation test was not positive . In three patients in addition to these bacteria also the presence of Helicobacter pylori was detected . Sera of eight patients with Gastrospirillum hominis were investigated by the ELISA test Helico-G f . Porton Cambridge; antibodies against Helicobacter pylori were found in three patients (incl . two with the concurrent presence of G.h . and H.p.) . In sera of the remaining five patients antibodies were not detected. Chirurg, 1993 Mar, 64(3), 190 - 4 {Plasma cell and sclerosing osteomyelitis . A follow-up of 21 patients}; Dohler JR et al.; Plasma cellular osteomyelitis was seen in the metaphysis while sclerosing osteomyelitis affected the diaphysis of long bones . In only about 20% of both forms local bacteria were noted . The onset of symptoms was inconspicuous and both clinical and radiological signs were nonspecific . Curettment or resection usually cured the disease . In some cases, however, aggressive surgery was necessary . As to surgery and outcome sclerosing osteomyelitis appeared less riskful than plasma cellular osteomyelitis . Both forms apparently represent the same basic pathological condition. Z Gastroenterol, 1993 Mar, 31(3), 198 - 200 Inflamed pancreatic pseudocyst: optimization of pseudocyst fluid culture technique; Ljubicic N et al.; A serious complication of pancreatitis, inflamed pseudocyst is associated with considerable morbidity and relatively high mortality rate . In this study chronic pancreatic pseudocyst fluid was cultured by the conventional method as well as by a method of bedside inoculation of blood culture bottles with pseudocyst fluid . The conventional method grew bacteria in only 26 (65%) of 40 patients with chronic pancreatic pseudocyst, whereas the blood culture bottles grew bacteria in 38 (95%) patients (p < 0.001) . The blood culture bottle method also resulted in more rapid detection of bacterial growth (p < 0.001) . Inoculation of pseudocyst fluid into the blood culture method seems more sensitive than the conventional method in detecting inflamed pancreatic pseudocyst probably due to the low pseudocyst concentration of bacteria observed in this study. Dis Mon, 1993 Mar, 39(3), 131 - 210 Acute mesenteric ischemia: pathophysiology, diagnosis, and treatment; Benjamin E et al.; Ischemia has traditionally been viewed as arising only from abnormalities of oxygen dynamics, namely the cellular hypoxia resulting from the imbalances between oxygen supply, consumption, and demand . Recently, it has become clear that such a view is too restrictive . Hypoperfusion may be caused by both anatomic and functional impediments to either inflow or to outflow from an organ . Furthermore, the pathophysiologic consequences are likely to involve not only cellular hypoxia, but also a restricted supply of nutrients and other important molecules and an abnormal elimination of physiologic wastes such as carbon dioxide . Hence the recommendation that ischemia be defined as a dual defect of oxygen deficit and carbon dioxide excess . AMI is, therefore, a severe anatomic or functional impediment to the splanchnic circulation, resulting in a dual defect of intestinal hypoxia and cellular hypercarbia . Although the functional and structural consequences of cellular hypoxia are well known, the pathophysiology of cellular hypercarbia has only begun to be explored . AMI syndromes include three related processes: occlusive mesenteric ischemia, nonocclusive ischemia, and sepsis-induced SI . Leakage of bacteria or bacterial toxins into the circulation during mesenteric ischemia forms the basis of the systemic components of this syndrome . Striving for an earlier diagnosis, treating the systemic (septic) consequences, and taking measures to promptly restore mucosal oxygen balance through aggressive pharmacologic and appropriate surgical intervention have significantly improved the prognosis . About 80% of patients with acute arterial embolism, 60% of those with nonocclusive ischemia, and only 20% of patients with arterial thrombosis are expected to live without significant residual nutritional deficits . The cause of death is usually sepsis and multisystem organ failure, and therefore, further reductions in mortality are likely to occur with the improved prevention and treatment of sepsis. Mol Plant Microbe Interact, 1993 Mar-Apr, 6(2), 238 - 52 Azorhizobium caulinodans nitrogen fixation (nif/fix) gene regulation: mutagenesis of the nifA -24/-12 promoter element, characterization of a ntrA(rpoN) gene, and derivation of a model; Stigter J et al.; Using site-directed mutagenesis, mutations were introduced in the -24/-12 promoter element of the Azorhizobium caulinodans nifA gene, and chimeric nifA-lacZ reporter gene fusions were constructed . Single base-pair mutations in the conserved -25 or -13 G residues were found to reduce or abolish nifA promoter activity, respectively, demonstrating that the -24/-12 promoter element is important for nifA gene expression and suggesting the involvement of a sigma 54 (NtrA/RpoN)-type transcription factor in nifA gene regulation . A 2-bp mutation at positions -25 and -16 was found to create a relatively nitrogen-control-independent, highly expressed nifA promoter . Using a heterologous ntrA(rpoN) gene probe, an A . caulinodans ntrA(rpoN)-like gene was cloned and the DNA sequence of this gene and flanking regions was determined . The presence of three open reading frames (ORF1-3) was demonstrated . ORF2 was found to contain regions sharing a high degree of homology with all characterized bacterial ntrA(rpoN) genes . ORF1 was found to share homology with ORFs found upstream of other bacterial ntrA(rpoN) genes, which have been postulated to encode members of a superfamily of ATP-binding proteins . Transposon Tn5 insertion mutations were introduced into the cloned ntrA(rpoN) gene, and chromosomal ntrA(rpoN)::Tn5 A . caulinodans mutants were created . The resulting mutants were found to be unable to fix nitrogen in the free-living state (Nif- in culture) or in stem or root nodules induced on Sesbania rostrata (Fix- in planta), and to be unable to grow aerobically in the presence of nitrate as sole nitrogen source (Ntr-) . A nifH-lacZ gene fusion was found to be silent in ntrA(rpoN)::Tn5 mutant strains, but a nifA-lacZ gene fusion was found to be expressed at a wild-type level, suggesting that the ntrA(rpoN) gene identified here controls the expression of some of the A . caulinodans nif genes, but not the central nif regulatory gene nifA . Based on these results, a new model for the regulation of nif/fix gene expression in A . caulinodans is proposed. Vet Pathol, 1993 Mar, 30(2), 119 - 29 Placental pathology of the pregnant mouse inoculated with Brucella abortus strain 2308; Tobias L et al.; Fifty-five pregnant BALB/c mice received various doses of Brucella abortus virulent strain 2308 intraperitoneally on day 9 of gestation, and uteri and spleens were examined at 3, 5, 7, and 9 days post-inoculation to study the pathogenesis of infection . A dose of 10(5.7) B . abortus organisms produced a severe, necrosuppurative placentitis . Bacteria multiplied preferentially within the placenta and were identified within the rough endoplasmic reticulum of trophoblast giant cells and within the visceral yolk sac endoderm . Abortions did not occur, but infarction of the labyrinth region of severely affected placentas occasionally resulted in fetal death . The severity of infection in the spleens of nonpregnant mice receiving the same challenge dose was not significantly different from that in the spleens of challenged pregnant mice . These results suggest that the sensitivity of the pregnant mouse to placental brucellosis is not due to a generalized immunosuppression but rather may involve a combination of local suppression of the immune response and a susceptible cell population suitable for Brucella colonization and replication . Experimental murine brucellosis resembles ruminant brucellosis and provides a model to study the intracellular replication of B . abortus in trophoblasts. Mol Microbiol, 1993 Mar, 7(5), 805 - 23 Characterization of a replicon of the moderately promiscuous plasmid, pGSH5000, with features of both the mini-replicon of pCU1 and the ori-2 of F; da Silva-Tatley FM et al.; The dominant, polA1-independent replicon of pGSH500, rep beta (1.8 kb), consists of a cis-acting oriV region of 245 bp; a repB gene that is essential for autonomous replication and 18, 30 to 36 bp iterons which constitute the inc/cop region . The molecular organization of rep beta resembles that of mini-pCU1 (IncN) . Furthermore, there is a 58% identity between the Rep proteins of these replicons . RepB also shows a 31% identity with RepE of mini-F . In addition, an 80% identity over 200 bp was identified between the cis-acting beta oriV region and the equivalent region of ori-2 (mini-F) . Replicons with deletions of repB could be complemented by Rep (pCU1) and RepE (mini-F) in trans, supporting the hypothesis that rep beta is a natural hybrid between a pCU1-like and F-like replicon. J Eukaryot Microbiol, 1993 Mar-Apr, 40(2), 172 - 9 Reclinomonas americana N . G., N . Sp., a new freshwater heterotrophic flagellate; Flavin M et al.; A new heterotrophic flagellate has been discovered from sites in Maryland, Michigan and Wyoming . The flagellate resides within a lorica constructed of a meshwork of intertwined fibrils with the outer surface invested with nail-shaped spines . The organism "reclines" within the lorica with its ventral aspect directed upward, and has two heterodynamic flagella, neither of which bears mastigonemes . One flagellum is directed upward and the other is arched over the ventral aspect of the body . Ingestion of bacteria takes place at the left posterior half of the cell . The organism is anchored to the lorica on the right posterior side by a series of regularly spaced cytoplasmic bridges and at the left anterior of the cell by a cytoplasmic appendage similar to the "languette cytoplasmique" found in some bicosoecids . The right side of the cell is raised into a flattened lip with the outer margin reinforced by a ribbon of microtubules . The new flagellate has mitochondria with tubular cristae and lacks a Golgi . A new genus is created to accommodate both the new flagellate described herein and Histiona campanula Penard . A new family is proposed to include the new genus and Histiona. Am J Phys Anthropol, 1993 Mar, 90(3), 359 - 71 Periodontal health in free-ranging baboons of Ethiopia and Kenya; Phillips-Conroy JE et al.; Frontal and lateral intraoral photographs of 19 baboons from the Awash National Park, Ethiopia and 37 baboons from Amboseli National Park, Kenya, were used to assess periodontal health . The Awash baboons, and two groups (Alto's and Hook's) at Amboseli, fed entirely from natural sources, but baboons from the third Amboseli group (Lodge) fed largely on food refuse from one of the park's lodges . Juveniles and adults were evaluated separately . Intraoral photographs were seriated based on visual appraisals of periodontal health . In both age groups, the best periodontal health was seen in Awash animals; Alto's and Hook's animals were intermediate, and the poorest health was seen in the Lodge sample . The periodontal health decreased with age in adult baboons, as reported in humans . Geochemistry, genetics, age, and diet (particularly variations in bacterial flora) were considered as factors contributing to the intergroup differences . Although it is not possible at present to exclude any of these as a contributing cause, we consider that diet in the broad sense (including food, water, and contamination by oral bacteria of human origin) probably plays a major role. J Clin Microbiol, 1993 Mar, 31(3), 642 - 5 Comparison of polymerase chain reaction with culture and enzyme immunoassay for diagnosis of pertussis; He Q et al.; A polymerase chain reaction (PCR) assay amplifying a segment of a repeated gene element of Bordetella pertussis was compared with culture and enzyme immunoassay (EIA) for the diagnosis of pertussis . The PCR assay was specific for B . pertussis in tests with a panel of other bacteria and with an extensive collection of specimen material from healthy persons and children with respiratory infections other than pertussis . The PCR assay was used in the analysis of 117 nasopharyngeal swabs collected from children at an elementary school at which a pertussis outbreak occurred . Fifty-six (48%) of the 117 swabs were positive, including those for all six culture-positive cases . The PCR method was then applied to analyze another pertussis outbreak . Of 40 nasopharyngeal aspirates taken from 37 clinically susceptible pertussis patients and from three asymptomatic contacts, the PCR identified 18 (45%), including all 3 culture-positive and 5 (35%) of the 14 seropositive patients . The most consistent and reliable diagnosis by positive PCR result was observed with those patients experiencing symptoms within 1 to 6 weeks of sample collection . We conclude that PCR is a rapid, sensitive, and specific means of diagnosing pertussis, especially during the first weeks of disease . The assay can be performed with both nasopharyngeal swabs and aspirates. Clin Perinatol, 1993 Mar, 20(1), 225 - 43 Breastfeeding . AIDS and other infectious diseases; Goldfarb J; Breastfeeding has recently been recognized as a mode of transmission of certain important pathogens . It is a major mode of transmission for CMV and HTLV-1 . HIV can also be transmitted by breastfeeding, but the relative role of breastfeeding in the epidemiology of HIV is still uncertain . Breastfeeding should continue to be encouraged in the HIV-infected woman, unless safe and sufficient quantities of infant formula are available . Expressed breast milk can be contaminated with bacteria or can contain viruses shed by the donor mother . Use of expressed breast milk should be carefully controlled, with strict attention to infection control issues in obtaining, storing, and processing the milk . Physicians should be aware of the risks of transmission of viral pathogens with fresh breast milk. J Med Microbiol, 1993 Mar, 38(3), 209 - 15 Opsonic requirements of Helicobacter pylori; McKinlay AW et al.; The opsonic requirements of Helicobacter pylori were investigated in a series of experiments with human polymorphonuclear leucocytes (PMNL) . Pre-incubation of H . pylori with pooled normal human serum (NHS) in concentrations of 5-20% significantly increased the uptake of radiolabelled bacteria by PMNL . Treatment of the bacteria with NHS 30% caused the release of radiolabel and this effect was abolished by heating serum to 56 degrees C, suggesting that H . pylori is serum-sensitive and that complement is involved . Opsonisation of H . pylori with NHS concentrations of 10-30% significantly increased PMNL chemiluminescence . Removal of specific antibody had no effect . Removal of either the classical or alternative complement pathways produced no significant change in PMNL chemiluminescence, indicating that either pathway is sufficient for opsonisation on its own . The results confirm that complement is the most efficient opsonin for H . pylori. J Med Microbiol, 1993 Mar, 38(3), 166 - 70 Rapid detection of Mycoplasma pneumoniae in clinical samples by the polymerase chain reaction; Kai M et al.; A DNA amplification method was used to detect Mycoplasma pneumoniae in clinical samples . M . pneumoniae 16S ribosomal RNA gene sequences were selected as the amplification target region . The polymerase chain reaction (PCR) with purified DNA fragments as templates yielded an expected 88-bp fragment from M . pneumoniae but not from other Mycoplasma spp . nor from any of the other bacteria assayed . With this method, the 88-bp product specific for M . pneumoniae could be obtained from a minimum of 0.05 pg of M . pneumoniae DNA . Subsequently this PCR technique was used for the detection of M . pneumoniae in throat-swab samples . Twenty-two of 30 culture-positive clinical samples gave positive results in the PCR test . Thirty-two culture-negative clinical samples and 33 samples from healthy volunteers, of which only one was culture-positive, gave negative results in the same PCR test . This PCR method is useful for the direct detection of M . pneumoniae in clinical samples. Ann Pharmacother, 1993 Mar, 27(3), 274 - 8 Contamination study of multiple-dose vials; Melnyk PS et al.; OBJECTIVE: To document the number of opened, dated, and expired multiple-dose vials (MDVs) in patient-care areas and to determine what proportion of MDVs were contaminated with bacteria or cellular debris . DESIGN: Every tenth opened MDV (69/656) identified on the wards was collected, ensuring representation from each nursing unit . Contents were examined for contamination . SETTING: Medical-school-affiliated, tertiary care center . MAIN OUTCOME MEASURES: (1) Visual inspection for debris, medication type, location, lot number, manufacturer's expiration date, and date of opening; (2) culture in solid and broth media for bacterial growth; and (3) staining and microscopic examination for cellular constituents . RESULTS: No vials had been dated after opening and 4.6 percent were expired according to the manufacturer's expiration date . No bacterial contamination was evident; however, one vial was contaminated with red blood cells . CONCLUSIONS: Transmission of infection via contaminated MDVs has been well documented and contamination with red blood cells raises concerns about potential for transmission of bloodborne pathogens . Recommendations include dating MDVs after opening, emphasizing the need for proper aseptic technique, and discarding MDVs on the manufacture's date of expiration. Genes Dev, 1993 Mar, 7(3), 367 - 79 The HAT4 gene of Arabidopsis encodes a developmental regulator; Schena M et al.; The HAT4 gene from the plant Arabidopsis thaliana encodes a homeo domain protein that contains a leucine zipper motif . Homeo domain-leucine zipper (HD-Zip) proteins have not been found in animal systems, suggesting that HAT4 may define a new family of transcription factors that regulate higher plant development . To explore this possibility, functional studies of HAT4 were carried out in yeast and in transgenic plants . Point mutants of HAT4 isolated in yeast define functionally critical residues within the HD-Zip domain, many of which correspond to highly conserved positions in known homeo domains and leucine zippers . Transgenic plants bearing constructs that alter HAT4 expression exhibit a series of interesting developmental phenotypes, including changes in morphology and developmental rate . Thus, the HAT4 gene of Arabidopsis encodes an HD-Zip protein that functions as a novel developmental regulator. Chest, 1993 Mar, 103(3), 896 - 9 Value of bedside plating of semiquantitative cultures for diagnosis of central venous catheter-related infections in ICU patients; Hnatiuk OW et al.; We compared semiquantitative central venous catheter tip cultures plated at the bedside with those cultured in the laboratory, to determine if bedside plating provides a significantly better yield . Paired segments of 197 catheter tips from 92 surgical and medical ICU patients were evaluated prospectively . A total of 31 catheter tip cultures were positive for > or = 15 organisms per agar plate, with 10 of these being simultaneously positive at the bedside and in the laboratory . Cultures were exclusively positive in 18 cases plated immediately at the bedside, whereas laboratory plating resulted in only 3 exclusively positive cases . This discrepancy was statistically significant (p < 0.005) . Compared with bedside plating, the sensitivity and specificity of sending catheters to the laboratory were 36 percent and 98 percent, respectively . These results indicate that the practice of sending central venous catheter tips to the laboratory for routine culture should be reconsidered in favor of bedside plating. Am J Kidney Dis, 1993 Mar, 21(3), 319 - 21 Peritonitis associated with disseminated Mycobacterium avium complex in an acquired immunodeficiency syndrome patient on chronic ambulatory peritoneal dialysis; Perazella M et al.; Chronic ambulatory peritoneal dialysis (CAPD) is a commonly used form of renal replacement therapy in patients with end-stage renal disease (ESRD) infected with the human immunodeficiency virus (HIV) . An increased incidence of peritonitis, as well as an increased rate of infections with unusual and serious organisms, has been reported in these patients . We report the first case of an HIV-infected patient who developed clinical peritonitis associated with Mycobacterium avium-intracellulare (MAI) infection . We suggest that the diagnosis of MAI peritonitis be suspected in HIV-infected patients with clinical CAPD peritonitis, negative cultures for bacteria or fungi, and a CD4 count less than 100 cells/microL . Therapy with a two-drug regimen for disseminated MAI infection without removal of the peritoneal dialysis (PD) catheter appears to provide symptomatic improvement while allowing ongoing PD. Proc Natl Acad Sci U S A, 1993 Mar 1, 90(5), 2030 - 4 Orientation of the LexA DNA-binding motif on operator DNA as inferred from cysteine-mediated phenyl azide crosslinking; Dumoulin P et al.; To address the question how the recognition helix of the LexA repressor is positioned within the major groove of operator DNA we have applied a site-specific photocrosslinking approach using a LexA mutant repressor (LexA-C52) that harbors a single cysteine side chain in position 52, close to the COOH terminus of helix 3 . The LexA-C52 mutant repressor has been purified and modified site-specifically with the photoreactive azido compound 4-azidophenacyl bromide, giving rise to LexA-C52* . Here we show that LexA-C52* may be selectively photocrosslinked with two adjacent bases within each operator half-site . The crosslinked bases are located, respectively, 10 and 11 base pairs from the dyad axis of the operator . The crosslinking data imply that the LexA recognition helix is oriented opposite to what is generally observed for helix-turn-helix proteins and that this helix should form a steeper angle with respect to the plane of the base pairs than is observed for standard helix-turn-helix proteins. J Bacteriol, 1993 Mar, 175(5), 1284 - 92 Unicellular, aerobic nitrogen-fixing cyanobacteria of the genus Cyanothece; Reddy KJ et al.; Two marine, unicellular aerobic nitrogen-fixing cyanobacteria, Cyanothece strain BH63 and Cyanothece strain BH68, were isolated from the intertidal sands of the Texas Gulf coast in enrichment conditions designed to favor rapid growth . By cell morphology, ultrastructure, a GC content of 40%, and aerobic nitrogen fixation ability, these strains were assigned to the genus Cyanothece . These strains can use molecular nitrogen as the sole nitrogen source and are capable of