Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| effects of rufloxacin in salmonella typhimurium infection in mice. | this study was undertaken to investigate the efficacy of rufloxacin, a new quinolone which is interesting due to its pharmacokinetics characterized by a long plasma half-life, in the treatment of systemic salmonella infections in the mouse typhoid model. innately susceptible balb/c and resistant cba mice were used to investigate the efficacy of rufloxacin in controlling systemic salmonella infections when given for brief or prolonged periods. the present study shows that rufloxacin is not only v ... | 1992 | 1337552 |
| the catalase-peroxidase of mycobacterium intracellulare: nucleotide sequence analysis and expression in escherichia coli. | the activation of catalase genes in response to oxidative stress may contribute to the intracellular survival of mycobacteria. in this report, the nucleotide sequence of a mycobacterial catalase gene is described. the deduced protein sequence of this mycobacterium intracellulare gene (mi85) was 60% identical to the escherichia coli hydroperoxidase i (hpi) protein, 59% identical to the salmonella typhimurium (hpi) catalase, and 47% identical to a bacillus stearothermophilus peroxidase. the mi85 p ... | 1992 | 1336034 |
| characterization of monoclonal antibodies to the outer membrane protein (ompd) of salmonella typhimurium. | a panel of monoclonal antibodies, seven against the trimeric and seven against the monomeric forms to outer membrane protein d (ompd) of salmonella typhimurium were produced. the specificities of these monoclonal antibodies for the porin proteins of s. typhimurium and their cross-reactions with salmonella porins ompc and ompf were determined by western immunoblotting and enzyme-linked immunosorbent assay. we observed that ompd shared more epitopes and had greater structural similarity with ompc ... | 1992 | 1335826 |
| purification and properties of nadp-dependent glutamate dehydrogenase from ruminococcus flavefaciens fd-1. | glutamate dehydrogenase (gdh) (l-glutamate:nadp+ oxidoreductase, deaminating, ec 1.4.1.4) from the cellulolytic ruminal bacterium ruminococcus flavefaciens has been purified and characterized. the native enzyme and subunit are 280 and 48 kda, respectively, suggesting that the native enzyme is a hexamer. the enzyme requires 0.5 m kcl for optimal activity and has a ph optimum of 6.9 to 7.0. the kms for ammonia, alpha-ketoglutarate, and glutamate are 19, 0.41, and 62 mm, respectively. the sigmoidal ... | 1992 | 1335719 |
| effects of tetanus toxin, salmonella typhimurium porin, and bacterial lipopolysaccharide on platelet aggregation. | endotoxins may interfere with platelet aggregation by interacting with the platelet membrane. the aim of this study was to evaluate the effects of tetanus toxin, salmonella typhimurium porin, and bacterial lipopolysaccharide (lps) on platelet aggregation induced by adp and thrombin in vitro. spontaneous platelet aggregation and platelet aggregation induced by adp and thrombin were measured. our results show that salmonella typhimurium porin and bacterial lps enhanced human and rabbit platelet ag ... | 1992 | 1335019 |
| active protection of mice against salmonella typhi by immunization with strain-specific porins. | nih mice were immunized with between 2.5 and 30 micrograms of two highly purified porins, 34 kda and 36 kda, isolated from the virulent strain salmonella typhi 9,12, vi:d. of mice immunized with 10 micrograms of porins, 90% were protected against a challenge with up to 500 ld50 (50% lethal doses) of s. typhi 9,12,vi:d and only 30% protection was observed in mice immunized with the same dose of porins but challenged with the heterologous strain salmonella typhimurium. these results demonstrate th ... | 1992 | 1333686 |
| rapid plasmid dna isolation from mucoid gram-negative bacteria. | exopolysaccharides interfere with the isolation and characterization of plasmid dna from gram-negative bacteria. to repress capsular polysaccharide production, bacteria were cultured in medium containing bismuth nitrate and sodium salicylate. rapid removal of other contaminating bacterial surface components was achieved by mild acidic zwitterionic detergent extraction. after treatment, bacterial cells were more readily lysed in alkaline detergents. the resulting plasmid preparations contained vi ... | 1992 | 1333482 |
| sequence of the sodium ion pump oxaloacetate decarboxylase from salmonella typhimurium. | a genomic library of salmonella typhimurium dna was constructed in the lambda-phage embl3 and screened by immunoblotting for expression of the oxaloacetate decarboxylase alpha-subunit. after subcloning on plasmids the entire sequence of the oxaloacetate decarboxylase was determined. the genes encoding subunits gamma (oadg), alpha (oada), and beta (oadb) of the decarboxylase are clustered on the chromosome in that order. a typical consensus sequence of a promoter is not found upstream of the oadg ... | 1992 | 1331067 |
| certain tryptophan photoproducts are inhibitors of cytochrome p450-dependent mutagenicity. | two photoproducts, derived from uv-irradiation of the amino acid l-tryptophan and with high ah (tcdd) receptor binding affinity, were tested for genotoxic and antimutagenic effects. the two indolo[3,2-b]carbazole derivatives, with the molecular weights of 284 and 312, respectively, were tested in saccharomyces cerevisiae strain d7 for mitotic gene conversion and reverse mutation and in strain rs112 for sister chromatid conversion and gene conversion. no significant (p > 0.05) genotoxic effects w ... | 1992 | 1330548 |
| in vitro antibacterial activities of tosufloxacin against and uptake of tosufloxacin by outer membrane mutants of escherichia coli, proteus mirabilis, and salmonella typhimurium. | the antibacterial activities of tosufloxacin and other quinolones against and apparent uptakes of tosufloxacin and other quinolones by outer membrane mutants of escherichia coli, proteus mirabilis, and salmonella typhimurium were studied. the hydrophobicity of tosufloxacin was nearly equal to that of ofloxacin or lower than those of sparfloxacin and nalidixic acid. ompf- and ompc-deficient e. coli and 40-kda porin-deficient p. mirabilis mutants were twofold more susceptible to tosufloxacin and s ... | 1992 | 1329639 |
| ribose and glucose-galactose receptors. competitors in bacterial chemotaxis. | the periplasmic ribose and glucose-galactose receptors (binding proteins) of gram-negative bacteria compete for a common inner membrane receptor in bacterial chemotaxis, as well as being the essential primary receptors for their respective membrane transport systems. the high-resolution structures of the periplasmic receptors for ribose (from escherichia coli) and glucose or galactose (from both salmonella typhimurium and e. coli) are compared here to outline some features that may be important ... | 1992 | 1328650 |
| isolation and characterization of the methionine aminopeptidase from porcine liver responsible for the co-translational processing of proteins. | a methionine aminopeptidase that specifically removes methionine residues from peptides with amino-terminal sequences of met-ala-, met-val-, met-ser-, met-gly-, and met-pro- but not met-leu- or met-lys- has been isolated to homogeneity from porcine liver by a procedure involving five chromatographic steps. the enzyme, whose specificity matches that predicted for the entity responsible for the co-translational amino-terminal processing of nascent polypeptide chains, has a measured molecular mass ... | 1992 | 1328207 |
| mgta and mgtb: prokaryotic p-type atpases that mediate mg2+ influx. | the gram-negative bacterium salmonella typhimurium possesses three distinct mg2+ transport systems, encoded by the cora, mgta, and mgtb loci. the cora transport system is the constitutive mg2+ influx system. it can also mediate mg2+ efflux at very high extracellular mg2+ concentrations. in contrast, the mgta and mgtb mg2+ transport systems are normally expressed only at low extracellular mg2+ concentrations. a strain of s. typhimurium was constructed by mutagenesis which lacks mg2+ transport and ... | 1992 | 1328179 |
| autogenous regulation of ethanolamine utilization by a transcriptional activator of the eut operon in salmonella typhimurium. | the genes required for use of ethanolamine as a carbon and nitrogen source are encoded by a single operon (eut) whose expression is induced by the simultaneous presence of both ethanolamine and cobalamin (vitamin b12). the action of b12 as an inducer of this operon reflects the fact that this cofactor is required by the degradative enzyme ethanolamine lyase (eutbc). the eutr gene encodes a protein that activates transcription of the eut operon in response to the simultaneous presence of b12 and ... | 1992 | 1328159 |
| preferential utilization of glucose over melibiose, and vice versa, in a pts mutant of salmonella typhimurium. | preferential utilization of glucose and melibiose was investigated in wild type cells and in pts mutant (ptsi-leaky) cells of salmonella typhimurium. a typical diauxic growth and preferential utilization of glucose over melibiose were observed in wild type cells when these two sugars were added as carbon source. similar results were obtained with a pts mutant (sb1476) although utilization of glucose was slow. when cyclic adenosine 3',5'-monophosphate (camp) was added to the culture medium to rel ... | 1992 | 1327563 |
| activity of a plasmid-borne leu-500 promoter depends on the transcription and translation of an adjacent gene. | leu-500 is a chromosomal promoter mutation in salmonella typhimurium that normally causes the promoter to be inactive in the initiation of rna synthesis. but in a strain that has mutations in topa, the gene encoding dna topoisomerase i, the mutant promoter becomes active. we show that the leu-500 promoter can function on a plasmid when it is adjacent to the tetracycline-resistance gene teta. activation of the leu-500 promoter requires that the teta gene is transcribed and translated and that the ... | 1992 | 1326763 |
| mutations that affect the regulation of phs in salmonella typhimurium. | the regulation of phs [production of hydrogen sulphide (h2s)] in salmonella typhimurium is complex. previous studies have shown that expression is dependent upon the presence of reduced sulphur and anaerobiosis and is modulated by carbon source and growth stage. transposon mutagenesis failed to find any potential trans-acting factors effective in the regulation of phs in relation to oxygen. spontaneous mutants capable of expressing phs-lac aerobically were isolated and characterized. these mutat ... | 1992 | 1326591 |
| escherichia coli prlc encodes an endopeptidase and is homologous to the salmonella typhimurium opda gene. | mutations at the escherichia coli prlc locus suppress the export defect of certain lamb signal sequence mutations. the salmonella typhimurium opda gene encodes an endoprotease that can participate in the catabolism of certain peptides and is required for normal development of phage p22. plasmids carrying either the wild-type (ptc100 prlc+) or suppressor alleles of prlc complemented all phenotypes associated with an s. typhimurium opda mutation. a plasmid carrying an amber mutation in prlc [prlc3 ... | 1992 | 1325967 |
| role of is1 in the conversion of virulence (vi) antigen expression in enterobacteriaceae. | when escherichia coli hb101 harbors pwr127, a plasmid comprising the viab gene from citrobacter freundii wr7004 and the cole1-derived packc1, the strain produces the virulence (vi) antigen. vi antigen expression is abolished (vi- phenotype), however, when an is1 or is1-like dna element inserts into the viab region. to determine the sites of is1 insertion, pwr127 dnas extracted from 95 independently isolated vi- strains were analyzed by digestion with the restriction endonuclease psti and agarose ... | 1992 | 1324399 |
| an unusual pagc::tnphoa mutation leads to an invasion- and virulence-defective phenotype in salmonellae. | two phenotypes believed to contribute to the pathogenesis of salmonella infections are macrophage survival and invasion of epithelial cells. it was recently observed that the salmonella macrophage survival factor pagc has significant amino acid similarity to the yersinia invasion factor ail. this observation raised the possibilities that macrophage survival is in part determined by the pathway of entry and that pagc confers an entry mechanism that does not trigger the microbicidal activities of ... | 1992 | 1323535 |
| identification, genetic analysis and dna sequence of a 7.8-kb virulence region of the salmonella typhimurium virulence plasmid. | the 90-kilobase (kb) virulence plasmid of salmonella typhimurium is responsible for invasion from the intestines to mesenteric lymph nodes and spleens of orally inoculated mice. we used tn5 and aminoglycoside phosphotransferase (aph) gene insertion mutagenesis and deletion mutagenesis of a previously identified 14-kb virulence region to reduce this virulence region to 7.8kb. the 7.8-kb virulence region subcloned into a low copy-number vector conferred a wild-type level of splenic infection to vi ... | 1992 | 1322485 |
| the fifth datta lecture. structural similarities between the aspartate receptor of bacterial chemotaxis and the trp repressor of e. coli. implications for transmembrane signaling. | a high resolution structure of the n-terminal ligand-binding domain of the aspartate receptor which mediates aspartate chemotaxis in salmonella typhimurium has recently been reported. a least-squares superposition of the alpha-amino nitrogen, alpha-carbon, beta-carbon, and alpha-carboxylate carbon of the aspartate bound to the aspartate receptor onto the equivalent atoms in the tryptophan bound to the trp repressor provides evidence for similarity between key parts of the active sites that bind ... | 1992 | 1322324 |
| electron spin resonance spectroscopy of oxygen radicals generated by synthetic fecapentaene-12 and reduction of fecapentaene mutagenicity to salmonella typhimurium by hydroxyl radical scavenging. | fecapentaenes form a class of potent fecal mutagens and have been suggested to play an initiating role in colon carcinogenesis. although several indications have been found that fecapentaenes may induce oxidative dna damage as well as dna alkylation, the mechanism of genotoxicity remains unknown. in this study, electron spin resonance spectroscopy with several spin traps has been used in order to determine whether reactive oxygen species can be formed by fecapentaene-12 (fp-12). no specific cond ... | 1992 | 1322251 |
| salmonella typhimurium porins stimulate platelet-activating factor synthesis by human polymorphonuclear neutrophils. | porins, a family of hydrophobic proteins located in the outer membrane of cell-wall of gram-negative bacteria, were shown to stimulate the synthesis and release of platelet-activating factor (paf), a 1-o-alkyl-2-acetyl-sn-glycerol-3-phosphorylcholine mediator of inflammation and endotoxic shock produced by polymorphonuclear neutrophils. paf synthesis was independent either from contamination by lps or generation of tnf. experiments with labeled precursors demonstrated that paf was synthesized vi ... | 1992 | 1321849 |
| alteration of neutrophil function in bcg-treated and non-treated swine after exposure to salmonella typhimurium. | salmonella typhimurium infection in swine causes an enterocolitis followed by a persistent carrier state, but little is known about the mechanisms that allow this organism to colonize and persist in host tissues. neutrophils provide a first line of defense against invading pathogens such as salmonella typhimurium. the purpose of this study was to evaluate porcine neutrophil function after in vivo exposure to salmonella and to determine if the immunomodulator, bacillus calmette guerin (bcg), exer ... | 1992 | 1321531 |
| [mutagenicity tests of suplatast tosilate (ipd-1151t)]. | 1. the reverse mutation test was carried out on suplatast tosilate (ipd-1151t) at dose range of 50-5000 micrograms/plate using salmonella typhimurium strains ta100, ta1535, ta98 ta1538 and ta1537, and escherichia coli strains wp2, wp2uvra. in all tester strains no significant differences were observed in the number of revertant colonies as compared with solvent control in the absence or presence of mammalian metabolic activation system. 2. the chromosomal aberration test on ipd-1151t was carried ... | 1992 | 1321262 |
| phosphorylation site of ntrc, a protein phosphatase whose covalent intermediate activates transcription. | the ntrc transcription factor is a member of a family of homologous prokaryotic regulatory proteins that participate in the transduction of extracellular and nutritional signals. it has been demonstrated that the phosphate group from a histidine residue of the phosphorylated ntrb protein autokinase is transferred to the ntrc protein. phosphorylation of the ntrc protein is transient and activates its transcriptional enhancement activity. we have investigated the site of phosphorylation of the sal ... | 1992 | 1321122 |
| starvation-inducible loci of salmonella typhimurium: regulation and roles in starvation-survival. | four starvation-inducible loci (stia, stib, stic, and stie) of salmonella typhimurium have been extensively characterized as to their genetic and physiologic regulation, and their roles in survival during prolonged simultaneous phosphate (p)-, carbon (c)- and nitrogen (n)-starvation (pcn-starvation). strains of s. typhimurium lt-2, isogenic with the exception of lacking either the stia, stib or stic locus, died off more quickly and survived at much reduced levels compared with their wild-type pa ... | 1992 | 1320726 |
| antibacterial and antiviral activity of camel milk protective proteins. | lysozyme (lz), lactoferrin (lf), lactoperoxidase (lp), immunoglobulin g and secretory immunoglobulin a were extracted from camel milk. the activity of these protective proteins was assayed against lactococcus lactis subsp. cremoris, escherichia coli, staphylococcus aureus, salmonella typhimurium and rotavirus. comparative activities of egg white lz, bovine lz and bovine lf are also presented. the antibacterial activity spectrum of camel milk lz was similar to that of egg white lz, and differed f ... | 1992 | 1319434 |
| the comparison of cell-mediated immunity induced by immunization with porin, viable cells and killed cells of salmonella typhimurium. | a marked level of cell-mediated immunity (cmi) to salmonella typhimurium-infection in mice, as determined by acquired resistance, delayed-type hypersensitivity, interleukin-2 production and interferon-gamma production, was induced by immunization with porin or viable cells but not with killed cells of s. typhimurium lt2. when the up-regulation of immune system to each immunogen was studied by comparing increases of ia-bearing macrophages, the immunization with porin or viable cells, but not kill ... | 1992 | 1318491 |
| the genes required for heme synthesis in salmonella typhimurium include those encoding alternative functions for aerobic and anaerobic coproporphyrinogen oxidation. | insertion mutagenesis has been used to isolate salmonella typhimurium strains that are blocked in the conversion of 5-aminolevulinic acid (ala) to heme. these mutants define the steps of the heme biosynthetic pathway after ala. insertions were recovered at five unlinked loci: hemb, hemcd, and heme, which have been mapped previously in s. typhimurium, and hemg and hemh, which have been described only for escherichia coli. no other simple hem mutants were found. however, double mutants are describ ... | 1992 | 1317844 |
| the swi4+ gene of schizosaccharomyces pombe encodes a homologue of mismatch repair enzymes. | the swi4+ gene of schizosaccharomyces pombe is involved in termination of copy-synthesis during mating-type switching. the gene was cloned by functional complementation of a swi4 mutant transformed with a genomic library. determination of the nucleotide sequence revealed an open reading frame of 2979 nucleotides which is interrupted by a 68 bp long intron. the putative swi4 protein shows homology to duc-1 (human), rep-3 (mouse), hexa (streptococcus pneumoniae) and muts (salmonella typhimurium). ... | 1992 | 1317550 |
| dissection of the salmonella typhimurium genome by use of a tn5 derivative carrying rare restriction sites. | a polylinker with rare restriction sites was introduced into a mini-tn5 derivative. these sites include m.xbai-dpni (tctagatctaga), which is rare in most bacterial genomes, swai (atttaaat) and paci (ttaattaa), which are rare in g+c-rich genomes, noti (gcggccgc) and sfii (ggccn5ggcc), which are rare in a+t-rich genomes, and blni (cctagg), spei (actagt), and xbai (tctaga), which are rare in the genomes of many gram-negative bacteria. this tn5(pfm) (pulsed-field mapping) transposon carries resistan ... | 1992 | 1317382 |
| in vivo administration of recombinant growth hormone or gamma interferon activities macrophages: enhanced resistance to experimental salmonella typhimurium infection is correlated with generation of reactive oxygen intermediates. | purified and recombinant forms of growth hormone (gh) as well as of recombinant rat gamma interferon (ifn-gamma) enhance the survival of rats deprived of endogenous pituitary gh secretion by hypophysectomy (hx rats) and infected with virulent salmonella typhimurium. macrophages obtained from rats with intact pituitaries (pituitary-intact rats) or hx rats that were treated in vivo with either gh or the closely related hormone prolactin released elevated (p less than 0.05) levels of superoxide ani ... | 1992 | 1316877 |
| early caulobacter crescentus genes flil and flim are required for flagellar gene expression and normal cell division. | the biogenesis of the caulobacter crescentus polar flagellum requires the expression of more than 48 genes, which are organized in a regulatory hierarchy. the flbo locus is near the top of the hierarchy, and consequently strains with mutations in this locus are nonmotile and lack the flagellar basal body complex. in addition to the motility phenotype, mutations in this locus also cause abnormal cell division. complementing clones restore both motility and normal cell division. sequence analysis ... | 1992 | 1315735 |
| detection of porin antigen in serum for early diagnosis of mouse infections with salmonella typhimurium. | the monoclonal antibodies to porin, an outer membrane protein isolated from salmonella typhimurium and sandwich enzyme linked immunosorbent assay (elisa) has made possible the detection of porin from sera of s. typhimurium-infected mice. the specificity of the monoclonal antibodies was ascertained based on their cross-reactivity with porins isolated from s. typhi, shigella flexneri and escherichia coli and lipopolysaccharide (lps) of s. typhimurium and e. coli. serum samples were found to be pos ... | 1992 | 1315558 |
| mutations in topa interfere with the inducible expression of dna damage response loci in salmonella typhimurium. | strains of salmonella typhimurium deficient in topoisomerase i activity (topa mutants) are uv sensitive and non-mutable (overbye and margolin: j bacteriol 146:170-178, 1981). using lac-operon fusions to dna damage inducible (din) loci we investigated whether these observations could be explained by an inability of topa strains to efficiently induce dna damage responses. mitomycin c (mmc)-induced expression of lac-operon fusions to uvrb and to a second sos locus, din-9, was largely eliminated in ... | 1992 | 1315267 |
| the poc locus is required for 1,2-propanediol-dependent transcription of the cobalamin biosynthetic (cob) and propanediol utilization (pdu) genes of salmonella typhimurium. | in this communication we present evidence that indicates that 1,2-propanediol (1,2-pdl) is a positive effector of the transcription of the cobalamin (vitamin b12) biosynthetic (cob) operon and of the 1,2-pdl utilization (pdu) genes. the stimulatory effects of 1,2-pdl were demonstrated using mu d-lac transcriptional fusions to cob and pdu. significantly increased levels of transcription of the cob and pdu operon fusions were measured in cultures grown under both anoxic and highly aerated conditio ... | 1992 | 1313000 |
| a single regulatory gene integrates control of vitamin b12 synthesis and propanediol degradation. | the cob operon of salmonella typhimurium encodes enzymes required for synthesis of adenosyl-cobalamin (vitamin b12). the pdu operon encodes enzymes needed for use of propanediol as a carbon source, including an adenosyl-cobalamin-dependent enzyme, propanediol dehydratase. these two operons both map near min 41 of the s. typhimurium linkage map and are transcribed divergently. here we report that the cob and pdu operons form a single regulon. transcription of this regulon is induced by either gly ... | 1992 | 1312999 |
| surface presentation of shigella flexneri invasion plasmid antigens requires the products of the spa locus. | an avirulent, invasion plasmid insertion mutant of shigella flexneri 5 (phs1059) was restored to the virulence phenotype by transformation with a partial hindiii library of the wild-type invasion plasmid constructed in pbr322. western immunoblot analysis of phs1059 whole-cell lysates revealed that the synthesis of the invasion plasmid antigens virg, ipaa, ipab, ipac, and ipad was similar to that seen in the corresponding isogenic s. flexneri 5 virulent strain, m90t. ipab and ipac, however, were ... | 1992 | 1312536 |
| structural relatedness of enteric bacterial porins assessed with monoclonal antibodies to salmonella typhimurium ompd and ompc. | the immunochemistry and structure of enteric bacterial porins are critical to the understanding of the immune response to bacterial infection. we raised 41 monoclonal antibodies (mabs) to salmonella typhimurium ompd and ompc porin trimers and monomers. enzyme-linked immunosorbent assays, immunoprecipitations, and/or western immunoblot techniques indicated that 39 mabs (11 anti-trimer and 28 anti-monomer) in the panel are porin specific and one binds to the lipopolysaccharide; the specificity of ... | 1992 | 1312535 |
| localization of the exonuclease and polymerase domains of bacillus subtilis dna polymerase iii. | structural gene mutants were cloned and exploited to identify the major catalytic domains of bacillus subtilis dna polymerase iii (bspoliii), a 162.4-kda [1437 amino acids (aa)] polymerase: 3'-5' exonuclease (exo) required for replicative dna synthesis. analysis of the sequence, mutagenicity, and catalytic behavior of natural and site-directed point mutants of bspoliii unequivocally located the domain involved in exonuclease catalysis within a 155-aa residue segment displaying homology with the ... | 1992 | 1312503 |
| identification of a salmonella typhimurium invasion locus by selection for hyperinvasive mutants. | salmonella typhimurium penetrate intestinal epithelial cells during infection. in vitro studies reveal that the availability of oxygen during bacterial growth decreases their capacity to adhere to and enter cultured epithelial cells. to identify s. typhimurium genes involved in epithelial cell entry, mutants were selected that entered hep-2 cells when grown under repressing, aerobic culture conditions. two types of transposons were used to generate bacterial mutations--transposons that disrupt g ... | 1992 | 1311853 |
| nitrobenzo[a]pyrene-induced dna amplification in sv40-transformed chinese hamster embryo cells. | nitrobenzo[a]pyrenes (nbaps) are ubiquitous environmental pollutants that produce mutations in salmonella typhimurium and chinese hamster ovary cells. in this study, 1-, 3-, and 6-nbap induced amplification of sv40 dna sequences in an sv40-transformed chinese hamster embryo cell line which is sensitive to dna amplification by various known carcinogens. of the three isomers, 3-nbap produced the highest level of gene amplification, which was 4.8 relative to untreated controls at a dose of 5 microg ... | 1992 | 1311674 |
| rapid mapping in salmonella typhimurium with mud-p22 prophages. | a new method for mapping mutations in the salmonella typhimurium chromosome is described and applied to the localization of novel regulatory mutations affecting expression of the nirb (nitrite reductase) gene. the mapping technique is also illustrated by the mapping of mutations in genes affecting carbohydrate catabolism and biosynthetic pathways. the new mapping method involves use of the hybrid phage mudp and mudq (together referred to as mud-p22), originally constructed by youderian et al. (g ... | 1992 | 1311301 |
| a physical map of the salmonella typhimurium lt2 genome made by using xbai analysis. | xbai digestion and pulsed-field gel electrophoresis of the genome of salmonella typhimurium lt2 yields 24 fragments: 23 fragments (total size, 4,807 kb) are from the chromosome, and one fragment (90 kb) is from the virulence plasmid pslt. some of the 23 fragments from the chromosome were located on the linkage map by the use of cloned genes as probes and by analysis of strains which gain an xbai site from the insertion of tn10. twenty-one of the fragments were arranged as a circular physical map ... | 1992 | 1311300 |
| a blni restriction map of the salmonella typhimurium lt2 genome. | blni or avrii (5'-cctagg) sites are very rare in the salmonella typhimurium lt2 genome. blni was used to construct a physical map which was correlated with the genetic map by using three methods. first, tn10 carries blni sites, and the extra restriction sites produced by 34 genetically mapped tn10 insertions were physically mapped by using pulsed-field gel electrophoresis. second, six genetically mapped mud-p22 prophage insertions were used to assign blni fragments. integration of mud-p22 introd ... | 1992 | 1311299 |
| interdomain salt bridges modulate ligand-induced domain motion of the sulfate receptor protein for active transport. | the refined crystal structure of the liganded form of the salmonella typhimurium sulfate-binding protein, a periplasmic receptor of active transport, is made up of two globular domains bisected by a deep cleft wherein the dehydrated sulfate is completely engulfed and bound by hydrogen bonds and van der waals' forces. two salt bridges (between glu15 and arg174 and between asp68 and arg134) span the cleft opening. to elucidate the role of the inter-domain salt bridges in the ligand-induced domain ... | 1992 | 1309886 |
| a method for constructing single-copy lac fusions in salmonella typhimurium and its application to the hema-prfa operon. | this report describes a set of escherichia coli and salmonella typhimurium strains that permits the reversible transfer of lac fusions between a plasmid and either bacterial chromosome. the system relies on homologous recombination in an e. coli recd host for transfer from plasmid to chromosome. this e. coli strain carries the s. typhimurium put operon inserted into trp, and the resulting fusions are of the form trp::put::[kanr-x-lac], where x is the promoter or gene fragment under study. the pu ... | 1992 | 1309519 |
| reaction of the nucleotide analogue 2-[(4-bromo-2,3-dioxobutyl)thio]adenosine 2',5'-bisphosphate at the coenzyme site of wild-type and mutant nadp(+)-specific glutamate dehydrogenases from salmonella typhimurium. | wild-type glutamate dehydrogenase (ec 1.4.1.4) from salmonella typhimurium reacts at 25 degrees c in 0.1 m phosphate buffer, ph 7, with the nucleotide analogue 2-[(4-bromo-2,3-dioxobutyl)thio]-adenosine 2',5'-bisphosphate (2-bdb-ta 2',5'-dp) to give 78% inactivation. protection against inactivation was achieved with nadph, indicating that modification occurred in the region of the coenzyme binding site. after reaction of the enzyme with 2-bdb-ta 2',5'-dp, the dioxo moiety of the bound reagent wa ... | 1992 | 1309291 |
| role of intestinal microflora in metabolism of glutathione conjugates of 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide. | dna adduct formation in the liver of b6c3f1 mice after administration of 1-nitropyrene (1-np) was shown by the 32p-postlabeling technique. the major adduct was not n-(deoxyguanosin-8-yl)-1-aminopyrene, which was easily formed in in vitro nitroreduction of 1-np in the presence of dna, but the major spots migrated to the same position as the in vitro dna adduct spots of k-region epoxides of 1-np (1-np 4,5- and 9,10-oxide). 1-np oxides formed by the oxidative activation of 1-np in the liver were ex ... | 1992 | 1306295 |
| extracellular export of shiga toxin b-subunit/haemolysin a (c-terminus) fusion protein expressed in salmonella typhimurium aroa-mutant and stimulation of b-subunit specific antibody responses in mice. | the shiga toxin b-subunit has been fused to the 23-kd c-terminus of escherichia coli haemolysin a (hlya) and exported from attenuated antigen carrier strain of salmonella typhimurium aroa (sl3261). the expression of the gene fusion under the control of a synthetic modified beta-lactamase promoter (constitutive expression) and under the iron-regulated aerobactin promoter showed that the fusion protein could be stably expressed and exported out of the bacterial cell in significant amounts so long ... | 1992 | 1302285 |
| antigen-binding diversity of human hybridoma autoantibodies derived from splenocytes of patients with sle. | the antigen-binding specificity of human hybridoma-derived monoclonal autoantibodies (mab) was analysed with mabs derived from the spleens of two patients with active systemic lupus erythematosus (sle). from one patient 72 mabs (rsp clones) and from the other 173 mabs (rt clones) were obtained. the binding specificity of these mabs was analysed by solid- and fluid-phase elisa against the autoantigens ssdna, dsdna, cardiolipin, smrnp, histones, sm-d and ss-b (la) synthetic peptides, and foreign a ... | 1992 | 1301976 |
| coexpression of the cys e and cys m genes of salmonella typhimurium in mammalian cells: a step towards establishing cysteine biosynthesis in sheep by transgenesis. | the salmonella typhimurium genes for serine acetyltransferase (cys e) and o-acetylserine sulphydrylase b (cys m) were isolated and characterized in order to express these as transgenes in sheep to establish a cysteine biosynthesis pathway and, thereby, to achieve an increased rate of wool growth. comparison of the s. typhimurium and escherichia coli genes showed considerable homology, both at the nucleotide and amino acid sequence levels. the in vitro and in vivo expression studies showed that b ... | 1992 | 1301209 |
| butylated hydroxyanisole produces both mutagenic and desmutagenic derivatives under gastric conditions. | dietary butylated hydroxyanisole (bha) has been known to have inconsistent functions on carcinogenesis, both prevention and initiation. we assumed that both functions of bha were introduced by the derivatives formed after the reaction with gastric components such as nitrite in the stomach. we then identified the derivatives produced by incubating bha with sodium nitrite at ph 2.0 or ph 5.0. eight derivatives were detected; 2-tert.-butyl-p-quinone (bq), 3,3'-di-tert.-butyl-biphenyldiquinone-(2,5, ... | 1992 | 1300306 |
| the biological interaction of cis- and trans-urocanic acid and dna. | the potential for the cis and trans isomers of urocanic acid to produce dna damage was measured by assays for dna binding (32p-postlabeling assay), for induction of dna repair (unscheduled dna synthesis assay) and induction of mutations (salmonella typhimurium and escherichia coli plate-incorporation assays). these assays did not detect any evidence of a direct effect of either isomer of urocanic acid on dna over a wide range of concentrations. these results suggest that neither isomer of urocan ... | 1992 | 1300140 |
| proliferative and t-cell specific interleukin (il-2/il-4) production responses in spleen cells from mice vaccinated with aroa live attenuated salmonella vaccines. | t-cell responses were studied in mice immunized with the salmonella typhimurium aroa sl3261 live attenuated vaccine strain. t-cell responses in the spleen, both in whole cell populations and in nylon wool non-adherent (t-cell enriched) cells, were studied in vitro as proliferation by incorporation of tritiated thymidine and production of t-cell specific cytokines [il-2 (interleukin-2)/il-4]. stimulating antigens included whole salmonella lysates and purified lipopolysaccharide (lps), both untrea ... | 1992 | 1298869 |
| urine mutagenicity in workers directly employed in coke production. | mutagenicity and toxicity of urine samples of 30 coke oven workers (group i) and 26 individuals composing a control group (group ii) was estimated using ames test with salmonella typhimurium strains ta 98 and ta 100. urine mutagenicity and toxicity, tested with strain ta 98 and metabolic activation, was significantly higher in group i than in group ii. using the strain ta 100, urine samples of coke oven workers showed only direct toxicity. mutagenic and toxic activity was observed mostly in work ... | 1992 | 1298485 |
| introduction of francisella tularensis at skin sites induces resistance to infection and generation of protective immunity. | mice are susceptible to systemic infection with francisella tularensis strain lvs; thus, the intraperitoneal (i.p.) lethal dose at 50% (ld50) in c3h/hen and c57bi/6j mice is only a single bacterium, while the intradermal (i.d.) ld50 is more than 10(4). here we show that the ld50 when lvs is introduced via the skin, either i.d. or subcutaneously (s.c.), ranges from 7 x 10(4) to 2 x 10(6). sublethal i.d. or s.c. infection (priming) invariably leads to the generation of systemic and specific protec ... | 1992 | 1297917 |
| [the urinary mutagenicity test in monitoring exposure to aromatic polycyclic hydrocarbons in workers in the aluminum industry]. | the sensitivity of 3 urinary mutagenicity tests was assayed: the plate test, the fluctuation test and the micropreincubation test, in order to assess their possible use in monitoring human exposure to polycyclic aromatic hydrocarbons (pah). urine samples from workers of an anode production plant exposed to coal tar and from psoriatic patients undergoing treatment with coal-tar ointments were tested for mutagenic activity on strain ta98 salmonella typhimurium, in the presence of the microsome fra ... | 1992 | 1297066 |
| photolabelling of salmonella typhimurium lt2 sialidase. identification of a peptide with a predicted structural similarity to the active sites of influenza-virus sialidases. | the sialidase from salmonella typhimurium lt2 was characterized by using photoaffinity-labelling techniques. the well-known sialidase inhibitor 5-acetamido-2,6-anhydro-3,5-dideoxy-d-glycero-d-galacto-non- 2-enonic acid (neu5ac2en) was modified to contain an amino group at c-9, which permitted the incorporation of 4-azidosalicylic acid in amide linkage at this position. labelling of the purified protein with the radioactive (125i) photoprobe was determined to be highly specific for a region withi ... | 1992 | 1295492 |
| [mutagenicity studies of prednisolone farnesylate (pnf)]. | prednisolone farnesylate (pnf) was tested for mutagenicity by ames test using salmonella typhimurium (ta100, ta1535, ta98, ta1537) and escherichia coli (wp2 uvra), for clastogenic activity in vitro by the chromosomal aberration test in a chinese hamster fibroblast cell line (chl), and for induction of micronuclei by the micronucleus test in male icr mice. 1) in ames test, pnf with and without metabolic activation showed no mutagenicity in any strains at any dose levels (312-5,000 micrograms/plat ... | 1992 | 1293327 |
| a 'safe-site' for salmonella typhimurium is within splenic polymorphonuclear cells. | following oral or systemic infection with salmonella typhimurium, the focus of infection is in the liver and spleen. the majority of salmonella surviving in the liver and spleen by 4 h post infection are already in an environment where they are largely protected from subsequent killing. previous studies have shown that the majority of surviving salmonella are intracellular. in the present study we sought to determine the cell type containing most of the cell-associated salmonella liberated from ... | 1992 | 1291841 |
| [the survival ability of salmonella, coccidia oocysts and ascarid eggs in laying hen feces from different housing systems]. | the time of survival of salmonella typhimurium, coccidia oocysts and ascaris eggs in manure of layer was determined in 5 different housing systems and 2 storing places for litter. the experiments were carried out in a stable of experimental station frankenforst of the university of bonn with a flock of 2200 hens. the effects of the environment conditions temperature, dry matter content, ph-value and intestinal microflora of the manure have also been studied. the time of survival was different de ... | 1992 | 1289044 |
| clavine alkaloids and derivatives as mutagens detected in the ames test. | eight cytostatic clavines were investigated for mutagenicity in salmonella typhimurium (reversion of the his-strains ta98, ta100, ta102 and ta1537), directly and in the presence of a mammalian xenobiotic metabolizing system, s9 (nadph-fortified postmitochondrial fraction of liver homogenate from aroclor 1254-treated rats). four compounds (festuclavine, 17-bromofestuclavine, 1-allylelymoclavine and 1-methyllysergol methyl ether) were direct mutagens, whose activity was enhanced in the presence of ... | 1992 | 1288732 |
| mg2+ transporting p-type atpases of salmonella typhimurium. wrong way, wrong place enzymes. | 1992 | 1288323 | |
| mutagenicity of analgesics, their derivatives, and anti-inflammatory drugs with s-9 mix of several animal species. | an investigation was undertaken to determine whether analgesics and their derivatives (13 compounds), and anti-inflammatory drugs (4 compounds) had mutagenicity. rec-assay was used to clarify specific dna-damaging properties, and the ames test was used to find back-mutations, using s-9 fractions obtained from the liver of 4 animal species pretreated with polychlorobiphenyl. in the rec-assay, salicylic acid (2 mg), aspirin (5 mg), benzoic acid (4 mg), sulpyrine (0.4 mg), indomethacin (0.1 mg), ox ... | 1992 | 1287147 |
| the rigidity of bacterial flagellar filaments and its relation to filament polymorphism. | we determined and correlated the rigidity of salmonella typhimurium, escherichia coli, and rhizobium lupini flagellar filaments representing various structural and polymorphic states (plain, complex, straight, superhelical, and right- and left-handed). persistence length, from which the filament's rigidity and other parameters (young's modulus, bending force constant, buckling persistence length, flexural deformation, and flexural time) were derived, was determined from electron micrographs of i ... | 1992 | 1286007 |
| salmonella typhimurium dt 203 in west yorkshire. | 1992 | 1285184 | |
| salmonella typhimurium dt 141. | 1992 | 1285151 | |
| salmonella typhimurium dt 203 update. | 1992 | 1285146 | |
| salmonella typhimurium dt 49. | 1992 | 1285117 | |
| antigen selection and presentation to protect against transmissible gastroenteritis coronavirus. | the antigenic structure of the s glycoprotein of transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) has been determined and correlated with the physical structure. four antigenic sites have been defined (a, b, c, and d). the sites involved in the neutralization of tgev are: a, d, and b, sites a and d being antigenically dominant for tgev neutralization in vitro. these two sites have specific properties of interest: site a is highly conserved and is present in c ... | 1992 | 1282756 |
| production and epidemiological application of monoclonal antibody specific for salmonella o5-antigen. | salmonella typhimurium is an important causative agent of acute gastroenteritis (food poisoning), and the decision of the source of infection urgently requires epidemiological investigation. there are two types of s. typhimurium, o5-antigen-carrier type (o5(+)-antigen type) and noncarrier type (copenhagen antigen type). on the assumption that serological differentiation of the types is effective for epidemiological exploration for the source of infection, we produced a monoclonal antibody, tmy1, ... | 1992 | 1282581 |
| mutagenic activity in wastewater concentrates from dye plants. | wastewater concentrates from the wastewater treatment systems of three dye plants were tested for mutagenic activity in salmonella typhimurium ta98 and escherichia coli wp2uvra using a fluctuation assay. concentrates were prepared by passing samples of wastewater (5-6 or 30 litres) through two porous resins (xad-2 and xad-7) in series. s. typhimurium in the presence of microsomal activation proved to be the more sensitive marker of mutagenicity. mutagenic responses were observed in concentrates ... | 1992 | 1282216 |
| rat pulmonary microsomal cytochrome p-450 enzymes involved in the activation of procarcinogens. | rat lung microsomal cytochrome p-450 (p-450) enzymes have been characterized with regard to their catalytic specificities towards activation of several procarcinogens to genotoxic metabolites in salmonella typhimurium ta1535/psk1002. we first examined the roles of rat liver microsomal p-450 enzymes in the activation of benzo[a]pyrene and its 7,8-diol enantiomers to genotoxic products, and found that p-450 1a1 is a major catalyst for the activation of these potential procarcinogens in rat livers. ... | 1992 | 1281274 |
| inhibitory activity of heat treated vegetables and indigestible polysaccharides on mutagenicity. | the effects of heat treated vegetables on mutagenicity were studied using the salmonella typhimurium system. the mutagens used were 3-amino-1-methyl-5h-pyrido[4,3-b]indole, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, 4-nitroquinoline-1-oxide, acridine yellow and 2-aminoanthracene. most of the heated vegetables unexpectedly showed greater inhibitory activity against the mutagenicity than unheated samples. the activity was increased markedly by heat treatment of water soluble indigestible polysacch ... | 1992 | 1281271 |
| mutagenicity testing of protein-containing and biological samples using the ames/salmonella plate incorporation test and the fluctuation test. | mutagenicity testing of biological samples and proteins is complicated by the presence of histidine and histidine-related growth factors which may produce a false positive result in the ames/salmonella plate incorporation test. a bioassay method, utilizing an automated dispenser-photometer and salmonella typhimurium strain ta1535 as the indicator bacteria, was used to estimate the presence of histidine-related growth factors in three enzyme solutions submitted for mutagenicity testing. one of th ... | 1992 | 1281266 |
| characterization of the salmonella typhimurium phoe gene and development of salmonella-specific dna probes. | in escherichia coli k-12, the phoe gene, encoding a phosphate-limitation-inducible outer membrane pore protein (phoe), is closely linked to the genes proa and prob. when the corresponding fragment of the salmonella typhimurium chromosome was transferred to e. coli k-12 using an rp4::minimu plasmid, pulb113, no production of s. typhimurium phoe could be detected. nevertheless, dna hybridization studies revealed that the corresponding plasmid did contain s. typhimurium phoe. production of s. typhi ... | 1992 | 1280609 |
| monoclonal antibodies against salmonella porins: generation and characterization. | monoclonal antibodies (mabs) were generated against porins, one of the major outer membrane proteins of salmonella typhi. six clones, designated mp1, mp2, mp3 (igg2ak), mpn4, mpn6 (igg1k) and mpn5 (igg2bk) were characterized by enzyme immunoassay (elisa) for their reactivity to porins from s. typhi, salmonella paratyphi a, s. paratyphi b, s. paratyphi c, salmonella choleraesuis, salmonella enteritidis, salmonella krefeld, salmonella panama, salmonella typhimurium, escherichia coli b, shigella fl ... | 1992 | 1280248 |
| assessment of the genotoxic potential of riboflavin and lumiflavin. b. effect of light. | on exposure to visible light, riboflavin and lumiflavin produced reactive oxygen species such as singlet oxygen and superoxide radicals. the reaction was found to be time- and concentration-dependent. both riboflavin and lumiflavin, upon illumination, showed mutagenic response in the umu test as well as in the ames/salmonella assay with salmonella typhimurium ta102. the mutagenic response was partially abolished by superoxide dismutase while sodium azide did not have any effect. no mutagenicity ... | 1992 | 1279412 |
| separation of two lipopolysaccharide populations with different contents of o-antigen factor 122 in salmonella enterica serovar typhimurium. | lipopolysaccharide (lps) extraction from smooth-type salmonella enterica sv. typhimurium was carried out with the modified phenol/chloroform/petroleum ether method (volume ratio 5:5:8). in this procedure, lps was precipitated from 90% phenol sequentially with water and acetone to yield lps-h2o (minute amounts) and lps-ac (major amounts), respectively. chemical analyses of the lps fractions revealed that in the o antigen of lps-h2o position c4 of the d-galactose was extensively glucosylated, corr ... | 1992 | 1279361 |
| [possible relationship between bacterial surface structures, immune-adherence, chemotaxis and phagocytosis (author's transl)]. | in the present study we attempted to determine the relationship between bacterial surface structures, immune adherence, chemotaxis and phagocytosis. as shown in table 1 encapsulated bacteria (klebsiella ozanae, k. pneumoniae, pasteurella multocida, streptococcus pneumoniae), mycoplasma pneumoniae and m. fermentans had a much lower immune adherence-activity than non-encapsulated bacteria (bacillus cereus, brucella abortus, erysipelothrix insidiosa, escherichia coli, listeria monocytogenes, pseudo ... | 1976 | 1258564 |
| the treatment of salmonellosis in equidae. | among 23 equidae in which various treatment or management regimens for salmonellosis were observed and evaluated, 9 horses were infected with salmonella typhimurium and 8 with s anatum; an aged mule harbored s newport, and 1 isolant was not identified. four dual sero-type infections occurred: 3 typhimurium/anatum and 1 anatum/newington. the results obtained with various antimicrobials in therapy of peracute, acute, and chronic infections were discouraging or questionable with regard to efficacy ... | 1976 | 1246235 |
| [blood cultures-bacteriological and drug resistance culture (author's transl)]. | blood cultures of 24 patients from the hospital das clinicas da faculdade de ciências médicas e biológicas de botucatu showed a prevalence of gram-negative isolates (83%) over gram-positive (16%). among the microorganisms salmonella typhimurium was the most frequent (25%) followed by klepsiella sp. (21%) and escherichia coli (17%). it was also observed that the main cuase of death was the largest occurrence of salmonella typhimurium and pseudomonas aeruginosa among the isolates. regarding drug r ... | 1975 | 1236053 |
| [bacteriological study of the intestinal flora of bats (desmodus rotundus) (author's transl)]. | stools of 100 bats trapped in the town of anhembi, state os são paulo, brazil, were examined bacteriologically. hemolityc and non hemolytic strains of escherichia coli were found most frequently (29.5%) followed by proteus group (27%) and staphylococcus (20%). from nine samples of stools the authors isolated salmonella typhimurium. | 1975 | 1236052 |
| studies on the methyl green-dna complex and its dissociation by drugs. | spectrophotometric results indicated that methyl green bound stably to native calf thymus dna and to poly[d(a-t)] but to a lesser extent to phix 174 dna, trnas, and poly(dg-dc), a copolymer that exists preferentially in the a conformation. exposing the methyl green-dna complex to graded concentrations of ethyl alcohol liberated part of the dye slowly by a zero-order reaction; higher alcohol concentrations which cause the b leads to a transition of dna released the bulk of methyl green. the visco ... | 1975 | 1191628 |
| the middleton outbreak: 125 cases of foodborne salmonellosis resulting from cross-contaminated food items served at a picnic and a smorgasbord. | one hundred and twenty-five of 173 people who ate at a picnic and/or a smorgasbord prepared by a bar-restaurant in a midwestern town in september 1973 developed diarrhea, abdominal cramps, and other symptoms 23 hours (median time) later. eleven were hospitalized. stool cultures from 18 ill individuals grew salmonella infantis, salmonella agona, and salmonella schwarzengrund. stool cultures from 5 of 8 restaurant employees grew s. infantis or s. agona. cultures of remaining foods and food-contact ... | 1975 | 1171616 |
| stimulation of derepressed enzyme synthesis in bacteria by growth on sublethal concentrations of chloramphenicol. | culturing of salmonella typhimurium or escherichia coli cells in the presence of low concentrations (</=1 mug/ml) of chloramphenicol (cap) permitted exponential growth, but at doubling times up to twice those of controls. when such cultures were subsequently starved for uracil or arginine, derepression of aspartate transcarbamylase (atcase) or ornithine transcarbamylase, respectively, was enhanced three- to 10-fold as compared to cultures not exposed to cap. enhancement of beta-galactosidase syn ... | 1975 | 1147588 |
| endotoxin from fusobacterium necrophorum of bovine hepatic abscess origin. | the endotoxic activity of fusobacterium necrophorum bov 5 was investigated. the supernatant (s) fluid and cell wall (cw) preparation, obtained after differential centrifugation of the ruptured cell mass, were lethal for mice. the toxicity of the s fluid was stable during prolonged storage, treatment with formalin, and heating for 15 minutes at 80, 100, and 121 c, but was destroyed by alkaline hydrolysis with 0.25 n naoh. the toxic factor was found in a high molecular weight (mw) fraction after g ... | 1975 | 1147341 |
| aflatoxicol h1: a major metabolite of aflatoxin b1 produced by human and rhesus monkey livers in vitro. | among the major metabolites of aflatoxin b1 produced by human and monkey livers in vitro is a derivative with the ketone carbonyl on the cyclopentane ring reduced to a secondary alcohol, and a hydroxyl introduced onto the carbon beta to the alcohol group. the metabolite was formed from aflatoxin b1 at a level similar to that of aflatoxin m1.both the microsomal hydroxylase and the cytoplasmic reductase systems are required for its formation. bioassay using chicken embryos and a mutant of salmonel ... | 1975 | 1135508 |
| alterations in hepatic chromatin template availability during infection. | hepatic chromatin was isolated from rats at various times after inoculation with either live or heat-killed bacteria. the chromatin was assayed under conditions that allow determination of the dna template available to support in vitro transcription. both a fulminant diplococcus pneumoniae and a milder salmonella typhimurium infection produced time-related increases in hepatic chromatin template availability when compared to chromatin isolated from rats inoculated with heat-killed bacteria. both ... | 1975 | 1130518 |
| the protection of mice against experimental infection by means of immunization with enriched membrane fraction of salmonella typhimurium. | 1975 | 1112368 | |
| man, his animals and salmonella typhimurium. | 1975 | 1110309 | |
| influence of subtherapeutic levels of oxytetracycline on salmonella typhimurium in swine, alves, and chickens. | subtherapeutic levels of oxytetracycline in animal feeds have been evaluated to determine their influence on the relative quantity, prevalence, shedding, and antibiotic susceptibility of salmonella typhimurium in swine, calves, and chickens, when compared with nonmedicated controls. the medicated groups were fed rations containing oxytetracycline commencing 5 days prior to oral inoculation with s. typhimurium and continuing through a 28-day post-inoculation period. colonization of s. typhimurium ... | 1975 | 1108781 |
| canine salmonellosis: a review and report of dog to child transmission of salmonella enteritidis. | dogs have been shown to harbor 53 salmonellae serotypes. multiple simultaneous infections with 2 to 4 serotypes have been observed. the prevalence of canine salmonellosis may be a high as 27 per cent. salmonella typhimurium and s. anatum are the most common etiologic agents. dogs commonly experience a sub-clinical course of salmonellosis. some investigators state that the dog may serve as a source of human infections. a few reports in the literature have documented this fact. the transmissions ... | 1976 | 1108681 |
| [study of the sensitivity of a morphological mutant of s. typhimurium to irradiation]. | morphological salmonella typhimurium lt2 wt--ed 143 mutant was similar by the character of the uv-sensitivity to the lon-mutants of escherichia coli k-12. the paper treats of the data on the uv-sensitivity of the mutant and the initial strains at various growth phases, by the capacity to restore the irradiated p22 and felix o bacteriophages and by the effect of various postradiational treatment on the irradiated strains. data are presented on densitometry of the membrane proteins of the initial ... | 1975 | 1108536 |
| [case of food poisoning caused by salmonella typhimurium]. | 1975 | 1108447 | |
| regulation of histidine operon does not require hisg enzyme. | mutations are described which delete all or part of the first structural gene (hisg) of the histidine operon of salmonella typhimurium. physiological regulation of histidine enzymes occurs normally in strains carrying any deletion that has both endpoints within the hisg gene. constitutive high operon expression is observed in strains carrying any hisg deletion and an unlinked regulatory mutation, hist1504. these results strongly indicate that the hisg protein is not an essential component of the ... | 1975 | 1108009 |
| genetic analysis of mutants of escherichia coli k12 and salmonella typhimurium lt2 deficient in hydrogenase activity. | a genetic study of mutants deficient in hydrogenase activity was performed. in e. coli, the affected gene (hyd) is located at 51 min, between cys c and nal b; in s. typhimurium, it probably lies in the homologous region of the chromosome. | 1975 | 1107810 |