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antibacterial activity of a synthetic peptide (pr-26) derived from pr-39, a proline-arginine-rich neutrophil antimicrobial peptide.pr-39 is a proline-arginine-rich (pr) neutrophil antibacterial peptide originally identified and purified from the porcine small intestine. we report on the synthesis of a functional antibacterial domain of pr-39, the first 26 amino acid residues of the nh2 terminus. pr-26 was as potent as or more potent than pr-39 against enteric gram-negative bacteria. this truncated form of pr-39 potentiated neutrophil phagocytosis of salmonella choleraesuis and decreased the level of s. typhimurium invasion ...19968787891
the identification, cloning and mutagenesis of a genetic locus required for lipopolysaccharide biosynthesis in bordetella pertussis.bordetella pertussis lipopolysaccharide (lps) is biologically active, being both toxic and immunogenic. using transposon mutagenesis we have identified a genetic locus required for the biosynthesis of lps in b. pertussis, which has been cloned and sequenced. we have also identified equivalent loci in bordetella bronchiseptica and bordetella parapertussis and cloned part of it from b. parapertussis. the amino acid sequences derived from most of the genes present in the sequenced b. pertussis locu ...19968821935
some properties and protective activity of specific dle against salmonella cholerae suis infection.from a rabbit lymphoid tissue, twice immunized with a salmonella ch. suis vaccine, was obtained a dialysable leucocyte extract (dle) (m. w. 10,000da; protein content 1.14 mg/ml; content of ribose 2.7 mg/ml; a260/a280 ratio 2.17 and ph 6.8). by gel filtration on sephadex g-25, six peaks were obtained and activity was found in peak iv. the activity of the extract was determined by a dermo-application test (dat) on 10 cows. the protective effect was tested by a challenge with salmonella ch. suis an ...19968993767
methanol extracts lps from deep rough bacteria.several rough strains of escherichia coli, salmonella enterica and proteus mirabilis were cultivated in the presence of (14c)acetate, which incorporated into their phospholipids and lipopolysaccharide. phospholipids were removed from the cells with ethanol extraction. however, as shown by thin layer chromatography, methanol additionally extracted remarkable quantities of lipopolysaccharide from deep rough strains, but not from bacteria containing complete or nearly complete core.19968605006
specific detection of salmonella enterica serotype enteritidis using the polymerase chain reaction.an assay was developed for the specific detection of salmonella enterica serotype enteritidis, using a novel application of the polymerase chain reaction (pcr). this pcr assay is based on the mismatch amplification mutation assay, an allele-specific reaction, and can discriminate enteritidis from all other salmonella. pcr primers were selected to amplify a 351-base pair (bp) dna fragment from the salmonella plasmid virulence a (spv a) gene of enteritidis. a single base difference at position 272 ...19968620904
c-terminal half of salmonella enterica wbap (rfbp) is the galactosyl-1-phosphate transferase domain catalyzing the first step of o-antigen synthesis.we previously showed that the product of the wbap gene of salmonella enterica serovar typhimurium has two functions: it is involved in the first step of o-antigen synthesis (the galactosyltransferase [gt] function) and in a later step (the t function), first thought to be the flipping of the o-antigen subunit on undecaprenyl pyrophosphate from the cytoplasmic face to the periplasmic face of the cytoplasmic membrane. we now locate two wbap(t) mutations within the first half of the wbap gene by se ...19968626328
linkage of genes essential for synthesis of a polysaccharide capsule in sphingomonas strain s88.several structurally related capsular polysaccharides that are secreted by members of the genus sphingomonas are being developed as aqueous rheological control agents for diverse industrial and food applications. they include gellan (s-60), welan (s-130), rhamsan (s-194), s-657, s-88, s-198, s-7, and nw-11. we refer to these polysaccharides as sphingans, after the genus name. this paper characterizes the first gene cluster isolated from a sphingomonas species (s88) that is required for capsule s ...19968626338
virulence and genotype stability of salmonella enterica serovar berta during a natural outbreak.strains of salmonella enterica serotype berta, collected over a period of 6 years from a well documented natural outbreak in denmark, have been characterized in order to assess the stability of chromosomal typing systems and virulence properties. outbreak strains were identical in pvu ii and psti is200 profiles, all but two strains showed the same sma i ribotype, and all but one strain showed the same not i pulsed field gel electrophoretic pattern, indicating that these molecular markers remaine ...19968666069
growth hormone modulates il-alpha and ifn-gamma release by murine splenocytes activated by lps or porins of salmonella typhimurium.the effect of growth hormone (gh) on the release of il-1alpha and ifn-gamma from murine splenocytes was investigated. their release from splenocytes activated by salmonella enterica serovar typhimurium lipopolysaccharide (lps) 0.5 microg/ml was increased by c. 65% in the presence of gh 100 pg/ml. with splenocytes activated by s. typhimurium porins 5 microg/ml, gh increased the production of both il-1alpha and ifn-gamma by c. 56%. polymyxin treatment abolished the cytokine-releasing activity of l ...19968667411
effect of dose on the immune response and persistence of salmonella choleraesuis infection in swine.to establish the effect of dose on persistence of and immune response to salmonella choleraesuis in swine.19968669761
[antibiotic resistance in salmonella enterica: an increasing problem].to determine the evolution of the frequencies of salmonella enterica serotypes and their resistance to antimicrobial agents.19969035708
a third family of allelic hsd genes in salmonella enterica: sequence comparisons with related proteins identify conserved regions implicated in restriction of dna.salmonella enterica serovar blegdam has a restriction and modification system encoded by genes linked to serb. we have cloned these genes, putative alleles of the hsd locus of escherichia coli k-12, and confirmed by the sequence similarities of flanking dna that the hsd genes of s. enterica serovar blegdam have the same chromosomal location as those of e. coli k-12 and salmonella enterica serovar typhimurium lt2. there is, however, no obvious similarity in their nucleotide sequences, and while t ...199628777503
[foodborne diseases: a survey on working methods used by 6 public health services in the lombardy region. 1. outbreaks].since foodborne diseases, especially those caused by bacteria, have become an increasingly important public health problem, the authors conducted a survey in order to evaluate the organization of, and the intervention carried out by, six public health services in the lombardia region, after reports of foodborne diseases outbreaks. lack of correct methodology was detected, not to mention the usual omission of epidemic curves and attack rates. besides, too many microbiological tests were made and ...19958679179
biology and clinical significance of virulence plasmids in salmonella serovars.non-typhoid salmonella strains containing virulence plasmids are highly associated with bacteria and disseminated infection in humans. these plasmids are found in salmonella serovars adapted to domestic animals, such as salmonella dublin and salmonella choleraesuis, as well as in the widely distributed pathogens salmonella typhimurium and salmonella enteritidis. although virulence plasmids differ between serovars, all contain a highly conserved 8-kb region containing the spv locus that encodes t ...19958845442
polymorphism of rrna genes and plasmid analysis in the typing of salmonella enterica serovar enteritidis from a spanish health area.a molecular epidemiological study of salmonella enterica serovar enteritidis (s. enteritidis) in a spanish health area was carried out using two genotypic methods; polymorphism of rrna genes (ribotyping) and plasmid analysis. the series included 100 isolates randomly selected from among those collected over the period 1984-92 (50 from sporadic episodes and 50 from 10 outbreaks). ribotyping using hindiii, smai, and ecori showed a notable degree of homogeneity within enteritidis serovar, it being ...19958590390
influence of inoculation route on the carrier state of salmonella choleraesuis in swine.this study was designed to investigate the carrier state of swine infected with salmonella choleraesuis. thirty-five pigs were divided into 3 groups. groups 1 (n = 15) and 2 (n = 16) were challenged with 10(8) cfu of s. choleraesuis intranasally or by gastric route, respectively. group 3 (n = 4) served as uninoculated controls. pigs were necropsied at 2, 4, 6, and 12 weeks post inoculation. clinical signs and microscopic lesions were more severe for group 1. salmonella choleraesuis was recovered ...19958604554
salmonella enterotoxin (stn) gene is prevalent among strains of salmonella enterica, but not among salmonella bongori and other enterobacteriaceae.all strains and serovars of salmonella enterica such as serovar typhimurium, enteritidis, dublin, typhi, etc. were found to carry the salmonella enterotoxin determinant stn as far as examined in pcr and hybridization studies. however, using mdck cells for testing the toxicity of the strains under investigation, only a limited number of stn positive strains revealed phenotypically the salmonella enterotoxin stn. in contrast to s. enterica, other enterobacteriaceae including salmonella bongori wer ...19958580901
dna fingerprint analysis of standard, intermediate, and variant antigenic types of salmonella enterica subspecies enterica serovar gallinarum biovar pullorum.dna fingerprint profiles and antigenic types of 150 salmonella enterica serovar gallinarum biovar pullorum field isolates and seven reference strains were evaluated. field isolates were submitted to the national veterinary services laboratories (nvsl), ames, iowa, between oct. 1, 1990, and aug. 20, 1991. three antigenic types (standard [n = 96], intermediate [n = 50], and variant [n = 4]) were identified among the field isolates. the ncii fingerprint profiles of all field isolates were identical ...19958561745
differentiation of strains from a food-borne outbreak of salmonella enterica by phenotypic and genetic typing methods.a combination of typing methods was used to identify the strains and the infection source in a food-borne outbreak of salmonella enterica occurring in a summer camp and affecting 25 children. all isolates tested were found to be serovar enteritidis, with an identical biotype api 20e and ribotype. however, they differed in their plasmid profiles and/or antibiograms, and were grouped into three strains. one strain was found in human stools, another in a hen's egg, and the third in both stools and ...19958549719
tumor necrosis factor-alpha production in swine after oral or respiratory challenge exposure with live salmonella typhimurium or salmonella choleraesuis.a series of experiments was conducted to document tumor necrosis factor-alpha (tnf) activity in serum of swine after inoculation with salmonella spp endotoxin and after oral or respiratory tract challenge exposure with live salmonella spp. for experiment 1, a potentially lethal dose of s typhimurium endotoxin (25 micrograms/kg of body weight) was administered iv, and serum tnf activity was measured. high tnf (approx 700 iu/ml) activity at 1 to 2 hours after administration of the inoculum was ass ...19958533971
genetic organisation and evolution of yersinia pseudotuberculosis 3,6-dideoxyhexose biosynthetic genes.3,6-dideoxyhexose (ddh) sugars occur in some of the o antigens of salmonella enterica and yersinia pseudotuberculosis, but are otherwise rarely found in nature. y. pseudotuberculosis ddh biosynthetic genes rfbs (encoding cdp-paratose synthetase) and rfbe (encoding cdp-tyvelose epimerase) were amplified and cloned, and their sequences determined. comparisons with the equivalent genes of s. enterica show that the genetic arrangement of ddh genes is very similar; however, in y. pseudotuberculosis t ...19958541300
the distribution of serotype-specific plasmids among different subgroups of strains of salmonella enterica serotype enteritidis: characterization of molecular variants by restriction enzyme fragmentation patterns.four hundred and thirty-four isolates of salmonella enterica serotype enteritidis were studied. they were grouped into five subsets defined by either the collection criteria or the parameter which formed the basis for subsequent analysis. seventy-seven per cent harboured the serotype-specific plasmid (ssp). in 55% of the isolates this was the sole plasmid. molecular variation in the ssp was detected in 17 (5%) of the isolates on the basis of restriction enzyme fragmentation pattern (refp) analys ...19957867741
serologic studies of experimentally induced salmonella choleraesuis var kunzendorf infection in pigs.two indirect elisa containing outer membrane protein (omp) and lipopolysaccharide (lps) antigens from a field isolate of salmonella choleraesuis var kunzendorf were developed and evaluated in experimentally infected and uninfected control pigs. experimentally induced infection with s choleraesuis was successfully established in 10 pigs by oral inoculation with 10(8) organisms, and 3 pigs died of clinical salmonellosis at postinoculation (pi) weeks 1, 2, and 4. swab specimens from tonsils, nostri ...19957486393
comparison of mics of ceftiofur and other antimicrobial agents against bacterial pathogens of swine from the united states, canada, and denmark.the mics of ceftiofur and other antimicrobial agents, tested for comparison, for 515 bacterial isolates of pigs from the united states, canada, and denmark with various diseases were compared. the organisms tested included actinobacillus pleuropneumoniae, escherichia coli, pasteurella multocida, salmonella choleraesuis, salmonella typhimurium, streptococcus suis, streptococcus dysgalactiae subsp. equisimilis, streptococcus equi subsp. equi, and streptococcus equi subsp. zooepidemicus. in additio ...19957494042
molecular, genetic, and topological characterization of o-antigen chain length regulation in shigella flexneri.the rfb region of shigella flexneri encodes the proteins required to synthesize the o-antigen component of its cell surface lipopolysaccharides (lps). we have previously reported that a region adjacent to rfb was involved in regulating the length distribution of the o-antigen polysaccharide chains (d. f. macpherson et al., mol. microbiol. 5:1491-1499, 1991). the gene responsible has been identified in escherichia coli o75 (called rol [r. a. batchelor et al., j. bacteriol. 173:5699-5704, 1991]) a ...19957532168
transferases of o-antigen biosynthesis in salmonella enterica: dideoxyhexosyltransferases of groups b and c2 and acetyltransferase of group c2.the o antigen is a polymer of oligosaccharide units. o antigens differ in their sugar composition and glycosidic linkages, and genes responsible for o-antigen-specific biosynthesis are grouped in the rfb gene cluster. in this study, we identified two abequosyltransferase genes and an acetyltransferase gene in salmonella enterica groups b and c2 by in vitro assay and identified paratosyl-, tyvelosyl-, and abequosyltransferase genes from s. enterica groups a and d and yersinia pseudotuberculosis s ...19957541787
lateral transfer of rfb genes: a mobilizable cole1-type plasmid carries the rfbo:54 (o:54 antigen biosynthesis) gene cluster from salmonella enterica serovar borreze.plasmid pwq799 is a 6.9-kb plasmid isolated from salmonella enterica serovar borreze. our previous studies have shown that the plasmid contains a functional biosynthetic gene cluster for the expression of the o:54 lipopolysaccharide o-antigen of this serovar. the minimal replicon functions of pwq799 have been defined, and a comparison with nucleotide and protein databases revealed this replicon to be virtually identical to cole1. this is the first report of involvement of cole1-related plasmids ...19957545154
effects of in vivo administration of anti-il-10 monoclonal antibody on the host defence mechanism against murine salmonella infection.interleukin-10 (il-10) is a cytokine that regulates various macrophage functions. to elucidate the involvement of endogenous il-10 in the early stage of murine salmonellosis, we examined the effect of anti-il-10 monoclonal antibody (mab) administration on the host defence mechanism against salmonella choleraesuis infection. the in vivo administration of anti-il-10 mab significantly enhanced host resistance at the early stage of salmonella infection, as assessed by bacterial growth in the periton ...19957558125
hard surface carrier test as a quantitative test of disinfection: a collaborative study.the hard surface carrier test (hsct) recently was proposed as a qualitative test for disinfectant efficacy. a collaborative study of hsct led to a suggested performance standard of < or = 2 or 3 positive carriers out of 60 tested. subsequently, it was discovered that hsct can be used as a quantitative test, because the hsct protocol requires measurement of inoculum level on some carriers. the data allow estimation of the log10 reduction in number of active bacteria. producers, consumers, and pol ...19957580324
sequence and analysis of the o antigen gene (rfb) cluster of escherichia coli o111.the o antigens found in salmonella enterica (se) and escherichia coli (ec) show a great deal of diversity, and only three structures are known to be common to both genera. two of them contain the 3,6-dideoxyheoxse colitose, not found in other serogroups of the two species. the first of these is common to ec o111 and se o:35 (sv adelaide); the other is found in both ec o55 and se o:50 (sv greenside). the genes specific for the synthesis of o antigen are generally located in the rfb gene cluster a ...19957590310
transcriptional regulation and promoter sequence of the spvr gene of virulence plasmid pkdsc50 in salmonella choleraesuis serovar choleraesuis.the transcript of the spvr gene on the virulence plasmid, pkdsc50, of salmonella choleraesuis serovar choleraesuis was detected for the first time by northern blot analysis, and the transcriptional regulation of the spvr gene was investigated. the transcription of the spvr was negatively regulated by spva and spvb, and enhanced at stationary phase under control of a sigma factor rpos (sigma 38). the spvr transcript was 2.4 kilonucleotides in salmonella cells, and deduced to encode spvr and spva, ...19957607404
relationship between evolutionary rate and cellular location among the inv/spa invasion proteins of salmonella enterica.for 21 strains of salmonella enterica, nucleotide sequences were obtained for three invasion genes, spao, spap, and spaq, of the chromosomal inv/spa complex, the products of which form a protein export system required for entry of the bacteria into nonphagocytic host cells. these genes are present in all eight subspecies of the salmonellae, and homologues occur in a variety of other bacteria, including the enteric pathogens shigella and yersinia, in which they are plasmid borne. evolutionary div ...19957638176
bacterial plasminogen receptors: in vitro evidence for a role in degradation of the mammalian extracellular matrix.the potential of bacterium-bound plasmin to degrade mammalian extracellular matrix and to enhance bacterial penetration through basement membrane was assessed with the adherent strain sh401-1 of salmonella enterica serovar typhimurium. typhimurium sh401-1 was able to bind plasminogen and to enhance the tissue-type plasminogen activator-mediated activation of the single-chain plasminogen to the two-chain plasmin. the end product, the enzymatically active, bacterium-bound plasmin activity, was als ...19957642304
mice deficient in gamma delta t cells are resistant to lethal infection with salmonella choleraesuis. 19957642318
endogenous interleukin 10 prevents apoptosis in macrophages during salmonella infection.to elucidate the biological roles of endogenous interleukin 10 (il-10) in macrophage responses during bacterial infection, we examined in vitro effects of neutralizing il-10 by anti-il-10 monoclonal antibodies (mab) on apoptosis of the peritoneal macrophages following salmonella choleraesuis infection. marked increments of tnf-alpha production were observed in the culture supernatant later than 6 h after in vitro culture with anti-il-10 mab. these macrophages succumbed to apoptosis at this stage ...19957646518
safety, efficacy, and duration of immunity induced in swine by use of an avirulent live salmonella choleraesuis-containing vaccine.an avirulent live salmonella choleraesuis culture (sc-54) was evaluated for use as an effective vaccine in preventing salmonellosis caused by s. choleraesuis in pigs. eighty-two pigs, 3 to 4 weeks old, were randomly assigned to 1 of 2 treatment groups, which were designated as either vaccinates or controls. after vaccination, all pigs were examined for fecal shedding of s choleraesuis, rectal temperature, and 10 clinical variables. significant difference was not detected between vaccinated and n ...19957695147
phage conversion in salmonella enterica serotype enteritidis: implications for epidemiology.a model system for the study of phage conversion of salmonella enterica serotype enteritidis is reported. temperate phages 1,2,3 and 6 from the phage typing scheme were used to convert several individually recognized phage types into others. phage type 4 was converted to pt8, pt6a to pt4, pt6a to pt7, pt13 to pt13a and pt15 to pt11; some new phage lysis patterns were also detected. this model was used to examine the relationships between phage types within a previously defined clonal lineage, se ...19957705486
diversity and molecular variation among plasmids in salmonella enterica serotype dublin based on restriction enzyme fragmentation pattern analysis.molecular variation within and between plasmids of salmonella enterica serotype dublin was analysed. such variation has been demonstrated in the serotype-specific plasmids (ssp's) of typhimurium and enteritidis. the two aims of this study were to determine the plasmid diversity in a host-adapted serotype and also the incidence of molecular variation in the ssp among strains of dublin using restriction endonuclease fragmentation pattern (refp) analysis with pst1, sma1 and ecorv. sixty-five strain ...19957705487
new extended-spectrum tem-type beta-lactamase from salmonella enterica subsp. enterica isolated in a nosocomial outbreak.a new extended-spectrum beta-lactamase was detected in a lactose-positive salmonella enterica subsp. enterica strain that caused a nosocomial outbreak involving eight patients in a pediatric cardiology unit. this strain showed high levels of resistance to ceftazidime and aztreonam and relatively low levels of resistance to cefotaxime and ceftriaxone. resistance was associated with a conjugative plasmid of 59 kb, which encoded a new beta-lactamase with an isoelectric point of 5.9 that strongly hy ...19957726515
genotypic and phenotypic analysis of salmonella strains associated with an outbreak of equine neonatal salmonellosis.isolates of salmonella choleraesuis serotype ohio (s. ohio) recovered during an outbreak of equine neonatal salmonellosis on a thoroughbred farm were compared with isolates of the same serotype from various animal, feed and environmental sources. biochemical profiles, antimicrobial susceptibility patterns, phage susceptibility, plasmid profiles, restriction endonuclease analysis and ribotyping were used to compare relatedness of the strains. a total of 46 outbreak and non-outbreak associated iso ...19957740753
septicemic salmonellosis in two llamas.at necropsy, salmonella choleraesuis var kunzendorf was recovered from the lungs of a 6-year-old female llama that died within a few days of onset of illness. the llama had had fence-line contact with 40 sows at a farm. salmonella typhimurium was isolated from a blood sample of a 6-day-old male cria that also died after a short illness.19957744668
nucleotide sequence of iaga and iagb genes involved in invasion of hela cells by salmonella enterica subsp. enterica ser. typhi. 19957754225
epidemiological evaluation by pcr ribotyping of sporadic and outbreak-associated strains of salmonella enterica serotype typhimurium.salmonella enterica serotype typhimurium has a very large diffusion worldwide within human and non-human hosts. the simultaneous circulation in the same geographical areas of many bacterial clones requires the use of reliable, reproducible and highly discriminatory typing techniques for epidemiological studies. molecular biological methods, such as plasmid profile analysis, restriction endonuclease digestion of plasmid and chromosomal dna and hybridization-based procedures have proven to be usef ...19957754232
[characteristics of biological properties of salmonella choleraesuis and salmonella typhisuis serovars]. 19957757368
the sixth and seventh cholera pandemics are due to independent clones separately derived from environmental, nontoxigenic, non-o1 vibrio cholerae.the dna sequences of the asd genes from 45 isolates of vibrio cholerae (19 clinical o1 isolates, 2 environmental nontoxigenic o1 isolates, and 24 isolates with different non-o1 antigens) were determined. no differences were found within either sixth- or seventh-pandemic isolates; however, variation was found between the two forms and among the non-o1 isolates. o139 isolates had sequences identical to those of seventh-pandemic isolates. phylogenetic trees with vibrio mimicus as the outgroup sugge ...19957768818
evidence for functional polymorphism of the spvr gene regulating virulence gene expression in salmonella.the expression of salmonella enterica spv virulence genes was studied in serovariants dublin and typhimurium using western blotting (immunoblotting), spv-lacz operon fusions and northern blotting. the spva protein was detected in immunoblots from stationary phase cultures of dublin but not from the corresponding cultures of typhimurium. transcriptional measurements, using a spva-lacz operon fusion, indicated 8-10 times higher spva transcription in dublin. in an isogenic escherichia coli chromoso ...19957891657
cloning and molecular analysis of the salmonella enterica ansp gene, encoding an l-asparagine permease.a gene (ansp), which encodes an l-asparagine permease, has been isolated from a cosmid library of salmonella enterica during screening for recombinant clones which encode l-asparaginase. nucleotide sequence analysis reveals that the gene product is a polypeptide of 497 amino acid residues, containing 12 putative transmembrane segments. the calculated molecular mass is 54 kda, although maxicell analysis by sds-page gave an apparent molecular mass of 37 kda. comparison of the deduced amino acid se ...19957894705
a retrospective case-control study of risk factors associated with salmonella enterica subsp. enterica serovar enteritidis infections on dutch broiler breeder farms.the organized control of salmonella enterica subsp. enterica serovar enteritidis (se) in the dutch poultry sector aims to prevent vertical transmission by the top-down approach, but its effectiveness is now undermined by the increasing role of horizontal transmission, so that preventive hygiene on the poultry farm gains significant importance. in order to assess the actual level of preventive hygiene and to identify risk factors, an inquiry was held among a representative number of broiler breed ...199518645784
salmonella enterica serovar gallinarum biovar gallinarum in layers: epidemiological investigations of a recent outbreak in denmark.despite the fact that no firm evidence was obtained, epidemiological investigations of a recent danish outbreak of fowl typhoid indicated that the infection might have been introduced by contaminated crates from a german slaughterhouse. fourteen danish and five german isolates of salmonella enterica serovar gallinarum biovar gallinarum obtained from recent outbreaks in denmark and germany were characterized by phenotypic and genomic methods. phenotypic characters, plasmid profiling, plasmid rest ...199418671116
clonal lines of salmonella enterica serotype enteritidis documented by is200-, ribo-, pulsed-field gel electrophoresis and rflp typing.sixty-two selected strains of salmonella serotype enteritidis of 33 phage types (pts), and one strain classified as rdnc, were characterised by four different chromosomally based typing methods to elucidate genetic relationships among strains of different phage types. based on is200-hybridisation patterns, two major groups, containing strains of the most commonly encountered phage types, and six minor groups (seven with the rdnc strain included) were observed. is200 pattern was a stable epidemio ...19947904649
immersion disinfection of irreversible hydrocolloid impressions with sodium hypochlorite. part i: microbiology.current american dental association infection control guidelines recommend immersion disinfection of irreversible hydrocolloid impressions, and this study further defines the parameters for use of sodium hypochlorite. sodium hypochlorite has been shown to be an effective disinfectant for impressions; however, it has not been fully evaluated for optimum immersion time and concentration. in this study, irreversible hydrocolloid impressions contaminated with different bacteria were immersed in vary ...19947916888
salmonella typhimurium phage types from human salmonellosis in denmark 1988-1993.a total of 989 isolates of salmonella enterica ssp. enterica serovar typhimurium from cases of human salmonellosis were investigated by phage typing. the isolates comprised all isolates recovered during the month of august in each of the years from 1988 to 1993. phage typing assigned 82.6% of the strains to 36 different definitive types, 11.9% of the strains belonged to types of unknown lysis pattern (rdnc), and 5.5% could not be typed by the phages used (nt). three phage types (12, 66 and 110) ...19947917221
intergeneric transfer and recombination of the 6-phosphogluconate dehydrogenase gene (gnd) in enteric bacteria.the gnd gene, encoding 6-phosphogluconate dehydrogenase (ec 1.1.1.44), was sequenced in 87 strains of 15 species assigned to five nominal genera of the enterobacteriaceae, including 36 isolates of salmonella enterica and 32 strains of escherichia coli. in s. enterica, the effective (realized) rate of recombination of horizontally transferred gnd sequences is only moderately higher than the rates for other chromosomal housekeeping genes. in contrast, recombination at gnd has occurred with such hi ...19947937867
genomic lineage of salmonella enterica serovar dublin.thirty five strains of the host adapted salmonella serotype dublin (s. dublin) have been characterized by is200 patterns, ribotyping, pulsed-field gel electrophoresis (pfge), restriction fragment polymorphism after hybridization with five randomly cloned dna-fragments of s. enteritidis (rflp), and plasmid profiling in order to divide the strains into 'genomic lines'. for comparison, 20 other strains of 9 different group-d serotypes were included. the is200 patterns were identical in all strains ...19947941292
in vitro synthesis of cdp-d-abequose using salmonella enzymes of cloned rfb genes. production of cdp-6-deoxy-d-xylo-4-hexulose, cdp-3,6-dideoxy-d-xylo-4-hexulose and cdp-3,6-dideoxy-d-galactose, and isolation by hplc.in vitro enzymic synthesis of cdp-d-[u-14c]abequose, cdp-6-deoxy-d-xylo-4-hexulose and cdp-3,6-dideoxy-d-xylo-4-hexulose was achieved using enzymes from cell extracts of cultures of escherichia coli strains harbouring and expressing genes of the rfb gene cluster of salmonella enterica lt2. from an initial synthesis step, cdp-6-deoxy-d-xylo-4-hexulose was isolated after 30 min reaction, using cdp-d-glucose, nad and cdp-glucose 4.6-dehydratase, followed by protein precipitation and desalting by ge ...19947957223
epidemic dissemination of salmonella enterica spp. enterica serovar bovismorbificans in southern italy in the years 1989-1991.epidemic strains of salmonella enterica subsp. enterica serovar bovismorbificans isolated in southern italy during the years 1989-1991 were submitted to a molecular epidemiological study in comparison with isolates identified in the years 1980-1988 in the same geographic area. genomic dna fragments obtained by digestion with bgli or eco ri hybridized with escherichia coli rrna to produce three distinct, but highly related patterns. ribotype 1, which had never been identified before 1989, was fou ...19947957796
reactive arthritis following an outbreak of salmonella infection in finland.the incidence and clinical features of reactive arthritis (rea) following an outbreak of enteritis caused by salmonella enterica ssp. enterica serovar 4,5,12:b:-were studied in the autumn of 1992. the outbreak occurred in several municipalities and originated from sprouted mung beans. a questionnaire on extra-enteric manifestations such as joint and eye symptoms was mailed 2 to 5 months after the outbreak to all bacteriologically proven cases. two hundred and forty-six of the 272 (90%) subjects ...19948000742
molecular analysis of the rfb gene cluster of a group d2 salmonella enterica strain: evidence for its origin from an insertion sequence-mediated recombination event between group e and d1 strains.the salmonella enterica o antigen is a highly variable surface polysaccharide composed of a repeated oligosaccharide (the o unit). the o unit produced by serogroup d2 has structural features in common with those of groups d1 and e1, and hybridization studies had previously suggested that the d2 rfb gene cluster responsible for o-unit biosynthesis is indeed a hybrid of the two. in this study, the rfb gene cluster was cloned from a group d2 strain of s. enterica sv. strasbourg. mapping, hybridizat ...19948021222
isolations of salmonella choleraesuis var kunzendorf from swine herds in southwestern ontario (1980-1993). 19948050078
regulation of spvr gene expression of salmonella virulence plasmid pkdsc50 in salmonella choleraesuis serovar choleraesuis.the expression regulation of spvr, a regulatory gene on the virulence plasmid (pkdsc50) of salmonella choleraesuis serovar choleraesuis, was investigated by spvr-lacz translational fusion. the spvr gene was found to be positively regulated by its own product, the spvr protein, and this unusual positive autoregulation was repressed by the products of spva and spvb, virulence-associated genes present downstream from the spvr gene. amino acid sequence analysis revealed that the amino-terminal regio ...19948052129
in vitro adhesion and invasion of salmonella enterica serovar havana.a total of 132 isolates of the havana serovar of salmonela enterica were studied for their adhesion to and invasion of hela cells in the presence of d-mannose. a total of 124 (93.9%) isolates were adherent, and 51% of these were invasive. of these 124 strains 82 (66%) adhered to hela cells with a pattern typical for enteroaggregative (eagg) escherichia coli whereas the remaining 34% adhered in a non-aggregative (non-eagg) pattern. of the 82 strains showing the eagg pattern 60% were invasive wher ...19948057827
increased occurrence of kcn-resistant salmonella strains.104 kcn-resistant salmonella strains were detected among 1391 strains typed (7.4%) during the first 7 months in 1993. in particular salmonella enterica strains of subspecies i isolated from humans and foods exhibited this character. those kcn-resistant salmonella strains did not belong to a special antigen formula. the second flagellar phase could not be detected in most of these strains. kcn resistance does not seem to be plasmid-encoded.19948061418
studies of the biosynthesis of 3,6-dideoxyhexoses: molecular cloning and characterization of the asc (ascarylose) region from yersinia pseudotuberculosis serogroup va.the 3,6-dideoxyhexoses are found in the lipopolysaccharides of gram-negative bacteria, where they have been shown to be the dominant antigenic determinants. of the five 3,6-dideoxyhexoses known to occur naturally, four have been found in various strains of salmonella enterica (abequose, tyvelose, paratose, and colitose) and all five, including ascarylose, are present among the serotypes of yersinia pseudotuberculosis. although there exists one report of the cloning of the rfb region harboring th ...19948071227
purification, characterization, and high performance liquid chromatography assay of salmonella glucose-1-phosphate cytidylyltransferase from the cloned rfbf gene.we report the purification and characterization of glucose-1-phosphate cytidylyltransferase, the first of five enzymes committed to biosynthesis of cdp-d-abequose from salmonella enterica strain lt2. the purification was greatly facilitated by using a cloned rfbf gene encoding this enzyme. pure enzyme was obtained by 64-fold enrichment in three chromatography steps. the nh2-terminal sequence of the purified enzyme was in agreement with the sequence predicted from the nucleotide sequence of the r ...19948276783
immersion disinfection of irreversible hydrocolloid impressions. part 1: microbiology.this study evaluated the effectiveness of four disinfectants for irreversible hydrocolloid impressions. impressions were made of a sterile metal model of the maxillary arch that had been contaminated with one of the following bacteria: staphylococcus aureus, salmonella choleraesuis, pseudomonas aeruginosa, mycobacterium bovis, or bacillus subtilis. the impressions were cultured before and after immersion in one of the following disinfectants: lodofive, omc ii, 0.525% sodium hypochlorite, or alci ...19947802909
molecular evolution in the gnd locus of salmonella enterica.the gnd gene, the structural gene for 6-phosphogluconate dehydrogenase, was sequenced and analyzed in 34 isolates from different serovars of the seven subspecies of salmonella enterica to provide comparative information on the evolution in this gene, which has been studied extensively in escherichia coli. the gene tree obtained by the neighbor-joining method in general gave separate branches for each subspecies, with the few exceptions readily explained by recombination. there is evidence of rec ...19947815922
evidence for effect of random genetic drift on g+c content after lateral transfer of fucose pathway genes to escherichia coli k-12.the cps cluster of escherichia coli k-12 comprises genes involved in synthesis of capsular polysaccharide colanic acid. part of the e. coli k-12 cps region has been cloned and sequenced and compared to its salmonella enterica lt2 counterpart. the cps genes from the two organisms are homologous; in the case of the lt2 genes, with g+c content of 0.61 and codons characteristic of high g+c species, it seems clear that they have been acquired relatively recently by lateral transfer from a high g+c sp ...19947815923
development of a conjoint phage typing & biotyping schema for salmonella enterica serovar senftenberg (s. senftenberg) & the correlation of biotypes with phage types.a total of 287 strains of s. senftenberg received from various parts of india during 1969 to 1992 were phage typed using six lysogenic phages. the typability was 90.3 per cent and 14 different phage types could be defined excluding a small group of untypable strains. a biotyping scheme was developed utilising six characters and 13 biotypes could be defined. stern's glycerol medium proved to be the best discriminatory medium. diversity indeces of phage typing and biotyping schemes were 0.868 and ...19947829162
[tetracycline-resistant plasmid of salmonella enteritidis isolated in kumamoto city].we isolated salmonella choleraesuis subsp. choleraesuis serovar. enteritidis (s. enteritidis) from a mass of cases which broke out in september, 1991 in kumamoto city. the isolates were shown to hold plasmids on which a tetracycline (tc)-resistant gene was located. the plasmid, about 9 kb in size, was capable of expressing the gene in escherichia coli, unstable in s. enteritidis and escherichia coli. thus in order to investigate the creeping prevalence of the tc-resistant plasmid in kumamoto cit ...19947829903
[presentation of salmonellosis in the tandil district, argentina].from january 1990 to july 1992 a prospective study on the salmonellosis form of presentation, reservoirs and transmission in tandil was carried out. forty strains of salmonella enterica were isolated with the following distribution: 28 humans (17 children and 11 adults), 6 in foods (1 in raw milk, 3 in well water, 1 in home made mayonnaise and 1 in chicken salad) and 6 in animals (1 in cow, 2 in chicken and 2 in calves). salmonella enteritidis was the most frequent isolate. disease was evident o ...19947838978
pulsed-field gel electrophoretic identification of salmonella enterica serovar typhimurium live vaccine strain zoosaloral h.salmonella enterica subsp. enterica serovar typhimurium (salm. typhimurium) live vaccine strain zoosaloral h was characterized by pulsed-field gel electrophoresis (pfge). each of the two suitable restriction enzymes, xbai and spei, produced a unique restriction fragment pattern for this live vaccine strain which was not shared by field isolates of the same serovar. the characteristic fragment pattern proved to be stable during a 22 month observation period and was also not altered after animal p ...19947765707
use of ribotyping, is200 typing and plasmid analysis for the identification of salmonella enterica subsp. enterica serovar typhimurium vaccine strain zoosaloral h and its differentiation from wild type strains of the same serovar.fifty salmonella enterica subsp. enterica serovar typhimurium (s. typhimurium) isolates obtained from one vaccinated and three non-vaccinated poultry flocks as well as the commercially available vaccine strain zoosaloral h and a s. typhimurium reference strain were characterized genotypically to differentiate between s. typhimurium live vaccine strain zoosaloral h and wild type strains of the same serovar. ribotyping revealed five different patterns one of which exclusively occurred in the vacci ...19947727890
phage types of salmonella enterica ssp. enterica serovar typhimurium isolated from production animals and humans in denmark.s. typhimurium is one of the 2 most common salmonella serotypes causing human salmonellosis in denmark. in order to illustrate the significance of different production animals as a source of infection, 1461 isolates were characterized by phage typing. the isolates originated from human patients and from cattle, pigs and poultry. by phage typing the isolates could be separated in 35 different phage types. five types (10, 12, 66, 110 and 135) predominated and comprised 78.8% of the isolates. in hu ...19947676916
[study of 2 food poisoning outbreaks in mora (toledo) with the same source of infection].the occurrence of an outbreak needs an immediate investigation, because on it depends the necessary measures to control the spread of the epidemic, and it is also the way of knowing the causal factor. we present the results of the investigation of two food poisoning outbreaks (outbreak a and outbreak b) occurred in mora (toledo). both outbreaks were reported at the same time, the source of infection was the same and the total number of exposed people was 620.19947618037
characterization of the rfc region of shigella flexneri.the o antigen of the shigella flexneri lipopolysaccharide (lps) is an important virulence determinant and immunogen. we have isolated s. flexneri mutants which produce a semi-rough lps by using an o-antigen-specific phage, sf6c. western immunoblotting was used to show that the lps produced by the semi-rough mutants contained only one o-antigen repeat unit. thus, the mutants are deficient in production of the o-antigen polymerase and were termed rfc mutants. complementation experiments were used ...19947507920
a plasmid-encoded rfbo:54 gene cluster is required for biosynthesis of the o:54 antigen in salmonella enterica serovar borreze.previous studies demonstrated that the presence of a 7-8 kb plasmid is correlated with expression of the lipopolysaccharide (lps) o:54 antigen in several salmonella enterica serovars. in this study, a 6.7 kb plasmid from a field isolate of s. enterica serovar borreze was shown to encode enzymes responsible for the synthesis of the o:54 polysaccharide. curing the plasmid results in simultaneous loss of smooth o-polysaccharide-substituted lps molecules and o:54 serotype. sds-page analysis of other ...19947512186
cloning and analysis of duplicated rfbm and rfbk genes involved in the formation of gdp-mannose in escherichia coli o9:k30 and participation of rfb genes in the synthesis of the group i k30 capsular polysaccharide.the rfbo9 gene cluster, which is responsible for the synthesis of the lipopolysaccharide o9 antigen, was cloned from escherichia coli o9:k30. the gnd gene, encoding 6-phosphogluconate dehydrogenase, was identified adjacent to the rfbo9 cluster, and by dna sequence analysis the gene order gnd-rfbm-rfbk was established. this order differs from that described for other members of the family enterobacteriaceae. nucleotide sequence analysis was used to identify the rfbk and rfbm genes, encoding phosp ...19947515042
genetic analysis of the o-specific lipopolysaccharide biosynthesis region (rfb) of escherichia coli k-12 w3110: identification of genes that confer group 6 specificity to shigella flexneri serotypes y and 4a.we recently reported a novel genetic locus located in the sbcb-his region of the chromosomal map of escherichia coli k-12 which directs the expression of group 6-positive phenotype in shigella flexneri lipopolysaccharide, presumably due to the transfer of o-acetyl groups onto rhamnose residues of the s. flexneri o-specific polysaccharide (z. yao, h. liu, and m. a. valvano, j. bacteriol. 174:7500-7508, 1992). in this study, we identified the genetic region encoding group 6 specificity as part of ...19947517390
involvement of the galactosyl-1-phosphate transferase encoded by the salmonella enterica rfbp gene in o-antigen subunit processing.rfbt of salmonella enterica lt2 was previously thought, together with rfal, to be involved in the ligation of polymerized o antigen to core-lipid a, and three mutants were known. we report the mapping of the mutations to rfbp, the galactosyl-1-phosphate transferase gene, which is now shown to encode a bifunctional protein. the mutations which have the former rfbt phenotype are referred to as rfbp(t). we also show that rfbp(t) mutants are not blocked in the ligation step as previously believed bu ...19947517393
usefulness of molecular genetic markers in the typing of salmonella enterica serovar enteritidis causing a food-borne outbreak.a combination of serotyping-phagetyping and three molecular genetic markers (plasmid analysis, chromosomic dna restriction pattern and ribosomal rna gene restriction pattern or ribotyping) was used in the typing of salmonella enterica causing a food-borne outbreak. the isolates analysed, 29 from stools and eight from foods, belonging to serovar enteritidis-phagetype a, carried a 36-mda plasmid, showed a similar dna restriction pattern and the same ribopattern. these data indicate that only one s ...19947521196
[the isolation of mutant salmonella cholerae-suis with the cya and crp phenotypes and a study of their biological properties]. 19947879548
molecular genetic basis of allelic polymorphism in malate dehydrogenase (mdh) in natural populations of escherichia coli and salmonella enterica.nucleotide sequences of the mdh gene encoding the metabolic enzyme malate dehydrogenase (mdh) were determined for 44 strains representing the major lineages of escherichia coli and the eight subspecies of salmonella enterica. sequence diversity was four times greater in s. enterica than in e. coli, and in both species the rate of amino acid substitution was lower in the nad(+)-binding domain than in the catalytic domain. divergence of the mdh genes of the two species apparently has not involved ...19948108402
antimicrobial susceptibility of actinobacillus pleuropneumoniae, pasteurella multocida and salmonella choleraesuis isolates from pigs.the in vitro susceptibility of 839 isolates of actinobacillus pleuropneumoniae, 969 isolates of pasteurella multocida and 104 isolates of salmonella choleraesuis from pigs to the fluoroquinolone danofloxacin, and eight other commonly used antimicrobial drugs was determined by veterinary diagnostic laboratories in europe, japan, south africa and north america between 1989 and 1991, by using a broth microdilution technique. the minimum inhibitory concentrations of danofloxacin, amoxycillin, ceftio ...19948128570
intermediate filament-like network formed in vitro by a bacterial coiled coil protein.the tlpa protein encoded by the virulence plasmid of salmonella enterica is an alpha-helical 371-amino acid protein possessing characteristics similar to eukaryotic coiled coil proteins (koski, p., saarilahti, h., sukupolvi, s., taira, s., rikkonen, p., osterlund, k., hurme, r., and rhen, m. (1992) j. biol. chem. 267, 12258-12265). in this paper we have investigated inter- and intramolecular associations and the morphology of structures formed by tlpa. dynamics and temperature stability of tlpa ...19948144657
recombinational basis of serovar diversity in salmonella enterica.the flic gene, which encodes phase 1 flagellin, was sequenced in strains of 15 salmonella enterica serovars expressing flagellar antigenic factors of the g series. the occurrence of each of the flagellin serotypes g,m, m,t, and g,z51 in distantly related strains is the result of horizontal exchange of dna, as indicated by identity or close similarity in nucleotide sequence of all or parts of the antigenic factor-determining central region of flic. the flagellin genes of some serovars are complex ...19948146152
photochemical inactivation of pathogenic bacteria in human platelet concentrates.platelet concentrates (pc) may be infrequently contaminated with low levels of bacteria that can cause septicemia and death in patients receiving transfusion therapy. we evaluated the efficacy of a photochemical decontamination (pcd) technique using 8-methoxypsoralen (8-mop) and long wavelength uv light (uva) to inactivate bacteria in standard therapeutic pc. twelve phylogenetically distinct pathogenic bacteria, 5 gram-positive and 7 gram-negative organisms, were seeded into pc to a final challe ...19948167348
characterization of the dtdp-rhamnose biosynthetic genes encoded in the rfb locus of shigella flexneri.the nucleotide sequence of the proximal half of the rfb region of shigella flexneri has been determined, and the genes encoding enzymes involved in the biosynthesis of dtdp-rhamnose have been identified. these genes show strong homology to the rfb genes encoding dtdp-rhamnose biosynthesis in salmonella enterica serovar typhimurium (strain lt2) and s. enterica serovar anatum (strain m32) (jiang et al., 1991; wang et al., 1992). an open reading frame upstream of rfbb was also identified which enco ...19948170390
the characterization of danish isolates of salmonella enterica serovar enteritidis by phage typing and plasmid profiling: 1980-1990.plasmid profiling, phage typing and antimicrobial resistance typing have been carried out on 736 isolates of salmonella enterica serovar enteritidis collected in denmark during the period 1980 to 1990. strains originated from cases of human salmonellosis, broiler poultry flocks, layer poultry flocks, quarantined imported poultry, environmental samples from hatchery units, and from bovines. phage type (pt) 1 was found to be the most common type among isolates of poultry origin (57.6%) followed by ...19948185887
sendai virus pneumonia: evidence for the early recruitment of gamma delta t cells during the disease course.we previously reported that gamma delta t cells appeared and could play a protective role early in infections with intracellular bacteria such as listeria monocytogenes, mycobacterium bovis bcg, and salmonella choleraesuis. to extend these findings to virus infection, we examined the developmental sequence of gamma delta t cells in bronchoalveolar lavage during the course of sendai virus infection in c57bl/6 mice. to produce a natural but nonlethal infection course as far as possible, we used a ...19948189536
[epidemiological studies in 2 episodes of food poisoning by salmonella enterica serovar enteritidis and the phenotypic and genotypic characterization of the epidemic strains]. 19948611233
[outbreaks of food poisonings of microbial and parasitic origins].in order to know the agents and foods related more frequently with food-borne disease outbreaks, we reviewed all the outbreaks studied between 1980 and 1989 by the national laboratory of public health. a total of 79 outbreaks of food-borne diseases of microbial origin were reviewed. the causative agent was identified in 50 (73%) outbreaks. twenty-four per cent of the outbreaks occurred in parties, 10.3 per cent in school or nurseries, 8.6 per cent in restaurants and 8.6 per cent in hospitals. st ...19938235891
identification of six open reading frames in the salmonella enterica subsp. enterica ser. typhi viab locus involved in vi antigen production. 19938248629
short-term treatment of traveler's diarrhea with norfloxacin: a double-blind, placebo-controlled study during two seasons.clinical efficacy of norfloxacin for treatment of traveler's diarrhea in 106 finnish tourists vacationing in morocco was evaluated during two different seasons. when the criteria for diagnosis of traveler's diarrhea were fulfilled, norfloxacin (400 mg) or a placebo was given orally, twice daily for 3 days. all symptoms and signs subsided sooner in the norfloxacin group. the clearest difference was observed in the duration of diarrhea: 1.2 days in the norfloxacin group vs. 3.3 days in the placebo ...19938268363
analysis of the antibiotic resistance detected in 2043 strains of salmonella enterica subsp. enterica isolated in stool cultures of spanish patients with acute diarrhoea (1986-1991). 19938125841
identification, expression, and dna sequence of the gdp-mannose biosynthesis genes encoded by the o7 rfb gene cluster of strain vw187 (escherichia coli o7:k1).the o7-specific lipopolysaccharide (lps) in strains of escherichia coli consists of a repeating unit made of galactose, mannose, rhamnose, 4-acetamido-2,6-dideoxyglucose, and n-acetylglucosamine. we have recently cloned and characterized genetically the o7-specific lps biosynthesis region (rfbeco7) of the e. coli o7:k1 strain vw187 (c. l. marolda, j. welsh, l. dafoe, and m. a. valvano, j. bacteriol. 172:3590-3599, 1990). in this study, we localized the gnd gene encoding gluconate-6-phosphate deh ...19937677991
repeat unit polysaccharides of bacteria: a model for polymerization resembling that of ribosomes and fatty acid synthetase, with a novel mechanism for determining chain length.we report the identification and sequence from escherichia coli and salmonella enterica strains of the cld gene, encoding the chain-length determinant (cld) which confers a modal distribution of chain length on the o-antigen component of lipopolysaccharide (lps). the distribution of chain lengths in the absence of this gene fits a model in which as the chain is extended there is a constant probability of 0.165 of transfer of growing chain to lps core, with termination of chain extension. the dat ...19937682279
glycosyl transferases of o-antigen biosynthesis in salmonella enterica: identification and characterization of transferase genes of groups b, c2, and e1.in salmonella enterica, there is a great variety of o antigens, each consisting of a short oligosaccharide (the repeating unit) repeated many times. the o antigens differ in their sugar composition and glycosidic linkages. the genetic determinants of the o antigen are located in an rfb gene cluster, and some, including those of s. enterica o serogroups b, c2, and e1, have been cloned and sequenced. in this study of the glycosyltransferases which form the glycosidic linkages, we identify and char ...19937684736
variation of the rfb gene clusters in salmonella enterica.in order to explore the genetic variation of o antigens of salmonella enterica, we surveyed 164 strains (132 serovars) belonging to 45 serogroups, using 25 mostly single-gene rfb dna probes for colony hybridization. the results revealed that strains within a serogroup have very similar or identical rfb genes. at least three of the four rhamnose genes were detected in all 17 serogroups reported to contain rhamnose, and one or more were detected in three others. the likelihood of being detected de ...19937687601
udp-sugar hydrolase isozymes in salmonella enterica and escherichia coli: silent alleles of usha in related strains of group i salmonella isolates, and of ushb in wild-type and k12 strains of e. coli, indicate recent and early silencing events, respectively.escherichia coli contains a single periplasmic udp-glucose hydrolase (5'-nucleotidase) encoded by usha. salmonella enterica, serotype typhimurium, also contains a single udp-glucose hydrolase but, in contrast to e. coli, it is membrane-bound and is encoded by the non-homologous ushb gene; salmonella enterica (typhimurium) also contains a silent allele of the usha gene (usha0). in this report, we show that nearly all natural isolates of salmonella contain both udp-sugar hydrolases, i.e. they are ...19938288106
acute phase response to salmonella in a pig liver perfusion model.livers from 7- to 14-day old pigs were maintained on a perfusion apparatus for 3 h. the perfused livers maintained physiologic and immunologic functions during perfusion. the perfused livers retained 78-94% of a non-recirculating inoculum of approximately 1-5 x 10(8) salmonella choleraesuis (scs), and cleared 94.9 +/- 1.7% of the retained (scs) during the 3-h perfusion period. when the acute phase response (apr) was induced in liver donor pigs 24 h before liver perfusion, the perfused livers had ...19938291202
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