Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| structural predictions of agfa, the insoluble fimbrial subunit of salmonella thin aggregative fimbriae. | the unusually stable and multifunctional, thin aggregative fimbriae common to all salmonella spp. are principally polymers of the fimbrin subunit, agfa. agfa of salmonella enteritidis consists of two domains: a protease-sensitive, 22 amino acid residue n-terminal region and a protease-resistant, 109 residue c-terminal core. the unusual amino acid sequence of the agfa core region comprises two-, five- and tenfold internal sequence homology patterns reflected in five conserved, 18-residue tandem r ... | 1999 | 10395827 |
| comparative study on the in vitro antibacterial activity of australian tea tree oil, cajuput oil, niaouli oil, manuka oil, kanuka oil, and eucalyptus oil. | to compare the antibacterial activity of the australian tea tree oil (tto) with various other medicinally and commercially important essential myrtaceous oils (cajuput oil, niaouli oil, kanuka oil, manuka oil, and eucalyptus oil) the essential oils were first analysed by gc-ms and then tested against various bacteria using a broth microdilution method. the highest activity was obtained by tto, with mic values of 0.25% for enterobacter aerogenes, escherichia coli, klebsiella pneumoniae, proteus m ... | 1999 | 10399193 |
| salmonella enterica serotype dublin infection: an emerging infectious disease for the northeastern united states. | salmonella enterica subspecies enterica serotype dublin (s. enterica dublin) emerged for the first time in new york, pennsylvania, and ohio in 1988. since that time this host-adapted serotype has spread throughout the veal- and dairy beef-raising operations in the region; very few dairy farms have experienced clinical s. enterica dublin infections. this study details the epidemiology of the outbreaks in cattle. during the period 1988 through 1995, nine new york and four pennsylvania counties hav ... | 1999 | 10405378 |
| molecular typing of multiple-antibiotic-resistant salmonella enterica serovar typhi from vietnam: application to acute and relapse cases of typhoid fever. | the rate of multiple-antibiotic resistance is increasing among salmonella enterica serovar typhi strains in southeast asia. pulsed-field gel electrophoresis (pfge) and other typing methods were used to analyze drug-resistant and -susceptible organisms isolated from patients with typhoid fever in several districts in southern vietnam. multiple pfge and phage typing patterns were detected, although individual patients were infected with strains of a single type. the pfge patterns were stable when ... | 1999 | 10405386 |
| a salmonella virulence protein that inhibits cellular trafficking. | salmonella enterica requires a type iii secretion system, designated spi/ssa, to survive and proliferate within macrophages. the spi/ssa system is encoded within the spi-2 pathogenicity island and appears to function intracellularly. here, we establish that the spi-2-encoded spic protein is exported by the spi/ssa type iii secretion system into the host cell cytosol where it interferes with intracellular trafficking. in j774 macrophages, wild-type salmonella inhibited fusion of salmonella-contai ... | 1999 | 10406797 |
| the selc-associated shi-2 pathogenicity island of shigella flexneri. | pathogenicity islands are chromosomal gene clusters, often located adjacent to trna genes, that encode virulence factors present in pathogenic organisms but absent or sporadically found in related non-pathogenic species. the selc trna locus is the site of integration of different pathogenicity islands in uropathogenic escherichia coli, enterohaemorrhagic e. coli and salmonella enterica. we show here that the selc locus of shigella flexneri, the aetiological agent of bacterial dysentery, also con ... | 1999 | 10411725 |
| antibody responses against flagellin in mice orally immunized with attenuated salmonella vaccine strains. | salmonella fiagellin has been repeatedly used as a carrier for heterologous peptide epitopes either as a parenterally delivered purified antigen or as a parenterally/orally-administered, flagellated, live, attenuated vaccine. nonetheless, the ability to induce specific antibody responses against the flagellin moiety, fused or not with heterologous peptide, has not usually been reported in mice orally inoculated with a live, attenuated, flagellated salmonella strain. in this work we evaluated the ... | 1999 | 10415171 |
| differential regulation of salmonella typhimurium type iii secreted proteins by pathogenicity island 1 (spi-1)-encoded transcriptional activators invf and hila. | salmonella enterica encodes a type iii protein secretion system within a pathogenicity island (spi-1) that is located at centisome 63 of its chromosome. this system is required for the ability of these bacteria to stimulate cellular responses that are essential for their pathogenicity. expression of components and substrates of this system is subject to complex regulatory mechanisms. these mechanisms involve the function of hila and invf, two transcriptional regulatory proteins encoded within sp ... | 1999 | 10417179 |
| multiple insertions of fimbrial operons correlate with the evolution of salmonella serovars responsible for human disease. | on centisome 7, salmonella spp. contain a large region not present in the corresponding region of escherichia coli. this region is flanked by sequences with significant homology to the e. coli trna gene aspv and the hypothetical e. coli open reading frame yafv. the locus consists of a mosaic of differentially acquired inserts forming a dynamic cs7 region of horizontally transferred inserts. salmonella enterica subspecies i, responsible for most salmonella infections in warm-blooded animals, carr ... | 1999 | 10417651 |
| plasmid-encoded tetracycline resistance in salmonella enterica subsp. enterica serovars choleraesuis and typhimurium: identification of complete and truncated tn1721 elements. | during routine screening of salmonella enterica subsp., s. enterica isolates of animal origin for plasmid-encoded tetracycline resistance, two tetracycline resistance plasmids, the 50 kbp plasmid pgft3 of salmonella choleraesuis and the 9.5 kbp plasmid pgft4 of salmonella typhimurium var. copenhagen dt002, were detected. the respective tetracycline resistance genes (tet) were identified by hybridization and pcr analysis to belong to hybridization class a. conjugation experiments identified plasm ... | 1999 | 10418136 |
| characterization of is1541-like elements in yersinia enterocolitica and yersinia pseudotuberculosis. | we characterized yersinia enterocolitica and yersinia pseudotuberculosis insertion sequences related to insertion sequence 1541, recently identified in yersinia pestis. for each of the two species, two insertion sequence copies were cloned and sequenced. genetic elements from y. pseudotuberculosis were almost identical to insertion sequence 1541, whereas these from y. enterocolitica were less related. phylogenetic analysis of the putative transposases encoded by insertion sequences from the thre ... | 1999 | 10418150 |
| salmonella level of danish swine herds based on serological examination of meat-juice samples and salmonella occurrence measured by bacteriological follow-up. | analyses of data collected in the danish salmonella control program in swine herds were conducted to assess the association between bacteriological and serological findings (including the degree to which changing serological status over time modulated the relationship) and to assess the degree to which type of swine operation and age group affected the relationship between bacteriological and serological findings. although serological status was significantly associated with bacteriological prev ... | 1999 | 10423781 |
| use of single-strand conformation polymorphism analysis to examine the variability of the rpos sequence in environmental isolates of salmonellae. | the natural environment places its resident microflora under stress, which may often result in adaptation by the microflora in order to increase the probability of survival. one such mechanism that has been postulated involves rpos, which encodes a sigma factor that is known to enhance survival upon exposure to stress. the present work aimed to examine the genetic variability of rpos in a selection of salmonella enterica subspecies environmental isolates with an automated single-strand conformat ... | 1999 | 10427052 |
| risk factors associated with salmonella enterica serovar typhimurium infection in danish broiler flocks. | a retrospective longitudinal study was conducted to identify risk factors associated with salmonella enterica serovar typhimurium (s. typhimurium) infection in danish broiler flocks. the data included all broiler flocks slaughtered in 1995, and the epidemiological unit was the individual broiler flock. the s. typhimurium status was determined by microbiological examination of 60 fresh fecal samples. this procedure should detect an infected flock with a probability above 95%, if the prevalence is ... | 1999 | 10438128 |
| antimicrobial activity of essential oils and other plant extracts. | the antimicrobial activity of plant oils and extracts has been recognized for many years. however, few investigations have compared large numbers of oils and extracts using methods that are directly comparable. in the present study, 52 plant oils and extracts were investigated for activity against acinetobacter baumanii, aeromonas veronii biogroup sobria, candida albicans, enterococcus faecalis, escherichia col, klebsiella pneumoniae, pseudomonas aeruginosa, salmonella enterica subsp. enterica s ... | 1999 | 10438227 |
| anti-immune trick unveiled in salmonella. | 1999 | 10438287 | |
| regulatory role of peritoneal nk1.1+ alpha beta t cells in il-12 production during salmonella infection. | nk1.1+ alpha beta t cells emerge in the peritoneal cavity after an i.p. infection with salmonella choleraesuis in mice. to elucidate the role of the nk1.1+ alpha beta t cells during murine salmonellosis, mice lacking nk1.1+ alpha beta t cells by disruption of tcr beta (tcr beta-/-), beta 2m (beta 2m-/-), or j alpha 281 (j alpha 281-/-) gene were i.p. inoculated with s. choleraesuis. the peritoneal exudate t cells in wild type (wt) mice on day 3 after infection produced il-4 upon tcr alpha beta s ... | 1999 | 10438944 |
| the role of intrahepatic gammadelta-t cells for liver injury induced by salmonella infection in mouse. | liver injury was induced after infection with salmonella choleraesuis 31n-1. in t-cell receptor-delta knockout mice, serum alanine transferase level was significantly decreased in comparison with normal control mice after salmonella infection. on the contrary, in vivo administration of anti-gammadelta t-cell receptor monoclonal antibody (uc7-13d5) to stimulate gammadelta-t cells in infected mice significantly increased serum alanine transferase level but decreased bacterial growth compared with ... | 1999 | 10449252 |
| the role of flagella, but not fimbriae, in the adherence of salmonella enterica serotype enteritidis to chick gut explant. | to gain an understanding of the role of fimbriae and flagella in the adherence and colonisation of salmonella enterica serotype enteritidis in chickens, an in-vitro gut adherence assay was developed and used to assess the adherence of a wild-type enteritidis strain and isogenic non-fimbriate and non-flagellate mutant strains. enteritidis strain s1400/94, a clinical isolate virulent in chickens, was shown to possess genes which encoded type 1, sef14, sef17, plasmid-encoded and long polar fimbriae ... | 1999 | 10451001 |
| characterization of dtdp-4-dehydrorhamnose 3,5-epimerase and dtdp-4-dehydrorhamnose reductase, required for dtdp-l-rhamnose biosynthesis in salmonella enterica serovar typhimurium lt2. | the thymidine diphosphate-l-rhamnose biosynthesis pathway is required for assembly of surface glycoconjugates in a growing list of bacterial pathogens, making this pathway a potential therapeutic target. however, the terminal reactions have not been characterized. to complete assignment of the reactions, the four enzymes (rmlabcd) that constitute the pathway in salmonella enterica serovar typhimurium lt2 were overexpressed. the purified rmlc and d enzymes together catalyze the terminal two steps ... | 1999 | 10455186 |
| attenuation and immunogenicity of deltacya deltacrp derivatives of salmonella choleraesuis in pigs. | six different isogenic deltacya deltacrp derivatives of a strain of salmonella choleraesuis var. kunzendorf-chi3246 virulent for pigs were constructed by transposon-mediated deletion mutagenesis. these strains were evaluated for virulence and ability to elicit a protective immune response in young weaned pigs after oral administration and were compared to a commercially available vaccine which lacks the 50-kb virulence plasmid (vpl(-)). these derivatives were deltacya deltacrp vpl(+), deltacya d ... | 1999 | 10456909 |
| virulence of salmonella enterica serotype enteritidis aflagellate and afimbriate mutants in a day-old chick model. | certain fimbriae and the flagellae of salmonella enterica serovar typhimurium have been shown to contribute to attachment and invasion of gut epithelium in the murine typhoid infection model and to contribute to pathogenesis in the chick. however, little is known of the role these organelles play in enteritidis poultry infections and, to study this, day-old chicks were dosed orally in separate experiments with defined multiply afimbriate and/or aflagellate mutant strains of enteritidis. the colo ... | 1999 | 10459641 |
| discrimination between endemic and feedborne salmonella infantis infection in cattle by molecular typing. | salmonella enterica serovar infantis is endemic in finnish cattle. feed contaminated with s. infantis was distributed to cattle farms in may 1995. following increased sampling, s. infantis was detected on 242 farms in 1995. molecular typing was used to differentiate the farms that were infected by the feed-related infantis from those infected by other endemic strains. twenty-three isolates from feed in 1995 and 413 from cattle (72 from 19924, 324 from 1995, 17 from 1996-7) were analysed. the fee ... | 1999 | 10459655 |
| membrane vesicles derived from pseudomonas aeruginosa and shigella flexneri can be integrated into the surfaces of other gram-negative bacteria. | incubation of intact salmonella typhi ty21a, salmonella enterica serovar typhimurium (salmonella typhimurium) aroa or escherichia coli dh5 alpha with membrane vesicles (mvs) derived from either shigella flexneri m90t or pseudomonas aeruginosa dsp89 resulted in a significant incorporation of vesicle antigens into the outer membrane of the bacteria; each recipient strain possessed a surface mosaic of new shigella and pseudomonas antigens intermixed with the native antigens of the salmonella or esc ... | 1999 | 10463171 |
| attachment of salmonella choleraesuis choleraesuis to beef muscle and adipose tissues. | the attachment of salmonella choleraesuis subsp. choleraesuis atcc 15790 to beef muscle and adipose tissues was investigated. s. choleraesuis was found to adhere in higher numbers to muscle than to fat. the charge and the hydrophobicity of the surface of s. choleraesuis were evaluated by measurement of electrophoretic mobility, the contact angle with water, adhesion to hexadecane, and hydrophobic interaction chromatography. the overall negative charge of s. choleraesuis was masked by the high el ... | 1997 | 10465034 |
| incidence of quinolone resistance over the period 1986 to 1998 in veterinary salmonella isolates from germany. | a total of 24,591 nonhuman salmonella strains isolated in germany between 1986 and 1998 were examined for their resistance to nalidixic acid by an agar diffusion method. the rate of resistance (inhibition zone, </=13 mm) ranged from 0.2% in 1986 to a peak of 14. 8% in 1990. between 1991 and 1998 the mics for nalidixic acid-resistant strains ranged from more than 256 microg/ml for nalidixic acid to between 0.25 and 128 microg/ml for enrofloxacin. in the early 1990s a particularly high incidence o ... | 1999 | 10471579 |
| an increase in sporadic and outbreak-associated salmonella enteritidis infections in wisconsin: the role of eggs. | in wisconsin, reported salmonella enterica serotype enteritidis (se) infections during 1997 more than doubled compared with the previous 9 years. a case-control study was conducted to determine risk factors for sporadic infections, and results of outbreak investigations were reviewed. eating raw eggs (matched odds ratio [mor]=14.5; 95% confidence interval [ci], 1.7-591.6), eating raw or undercooked eggs (mor=5.8; 95% ci, 1.3-28.0), eating any eggs (mor=4.2; 95% ci, 1.2-16.2), and dining at a res ... | 1999 | 10479150 |
| molecular characterization of the pmra regulon. | the two-component system pmra/pmrb of salmonella enterica controls expression of several loci including those mediating modifications in the lipopolysaccharide that result in polymyxin resistance. to gain insight in the regulation of polymyxin resistance, we mapped the transcription start sites of the pmra-regulated genes pmrc, pmrg, pbgpe, and ugd and identified a conserved sequence in the promoter region of the first three genes. his-tagged pmra protein could gel shift dna fragments containing ... | 1999 | 10480935 |
| cost-effective methods for isolation of salmonella enterica in the clinical laboratory. | data from 8,717 fecal specimens indicate that primary inoculation of xylose lysine deoxycholate (xld) agar may enhance the speed, but not the sensitivity, of isolation of salmonella enterica over that achieved with selenite enrichment only. plating of selenite broth onto both brilliant green and xld agar offers no advantage over plating onto xld alone. | 1999 | 10488209 |
| emergence and spread of an atypical salmonella enterica subsp. enterica serotype 4,5,12:i:- strain in spain. | 1999 | 10488227 | |
| pulsed field gel electrophoresis identifies an outbreak of salmonella enterica serotype montevideo infection associated with a supermarket hot food outlet. | in february 1996 salmonella enterica serotype montevideo infection in a patient in the north tyneside area was attributed to consumption of cooked chicken bought from a supermarket hot food outlet. isolates from the patient, leftover food, and environmental samples were indistinguishable by pulsed field gel electrophoresis (pfge). pfge also demonstrated that an outbreak of infection with s. montevideo associated with the hot food outlet had occurred in late 1995 and early 1996. this study shows ... | 1999 | 10491878 |
| endogenous il-15 might be responsible for early protection by natural killer cells against infection with an avirulent strain of salmonella choleraesuis in mice. | interleukin (il)-15 is a novel cytokine with growth factor activity for t cells, b cells, and natural killer cells (nk cells). we investigated the role of il-15 in the host defense against infection with avirulent salmonella choleraesuis strain 31n-1 cured of 50-kb virulent plasmid. il-15 was abundantly expressed at transcription and protein levels in macrophages infected with s. choleraesuis 31n-1. the number of nk cells in the infected sites was increased during the course of infection coincid ... | 1999 | 10496307 |
| use of in vivo-regulated promoters to deliver antigens from attenuated salmonella enterica var. typhimurium. | this study describes the construction and analysis of three in vivo-inducible promoter expression plasmids, containing pnirb, ppagc, and pkatg, for the delivery of foreign antigens in the deltaaroad mutant of salmonella enterica var. typhimurium (hereafter referred to as s. typhimurium). the reporter genes encoding beta-galactosidase and firefly luciferase were used to assess the comparative levels of promoter activity in s. typhimurium in vitro in response to different induction stimuli and in ... | 1999 | 10496887 |
| the propanediol utilization (pdu) operon of salmonella enterica serovar typhimurium lt2 includes genes necessary for formation of polyhedral organelles involved in coenzyme b(12)-dependent 1, 2-propanediol degradation. | the propanediol utilization (pdu) operon of salmonella enterica serovar typhimurium lt2 contains genes needed for the coenzyme b(12)-dependent catabolism of 1,2-propanediol. here the completed dna sequence of the pdu operon is presented. analyses of previously unpublished pdu dna sequence substantiated previous studies indicating that the pdu operon was acquired by horizontal gene transfer and allowed the identification of 16 hypothetical genes. this brings the total number of genes in the pdu o ... | 1999 | 10498708 |
| salmonella enterica serovar. typhimurium phage type dt104 and other multi-drug resistant strains in japan. | 1999 | 10507998 | |
| the outer membrane of gram-negative bacteria inhibits antibacterial activity of brochocin-c. | brochocin-c is a two-peptide bacteriocin produced by brochothrix campestris atcc 43754 that has a broad activity spectrum comparable to that of nisin. brochocin-c has an inhibitory effect on edta-treated gram-negative bacteria, salmonella enterica serovar typhimurium lipopolysaccharide mutants, and spheroplasts of typhimurium strains lt2 and sl3600. brochocin-c treatment of cells and spheroplasts of strains of lt2 and sl3600 resulted in hydrolysis of atp. the outer membrane of gram-negative bact ... | 1999 | 10508055 |
| salmonella abortusequi strains of equine origin harbor a 95kb plasmid responsible for virulence in mice. | most salmonella choleraesuis subsp. choleraesuis serovar abortusequi strains of equine origin harbor a 95kb plasmid, psa95. results of pcr and southern blot analysis suggest that psa95 contains spv genes. a psa95-cured strain of s. abortusequi was 48 times less virulent to mice than its parental strain. virulence was restored by reintroduction of psa95. these results provide clear evidence that psa95 confers virulence on s. abortusequi in mice. this is the first report describing a virulence pla ... | 1999 | 10510045 |
| interaction of salmonella choleraesuis, salmonella dublin and salmonella typhimurium with porcine and bovine terminal ileum in vivo. | quantitative experiments on the interaction of salmonella choleraesuis and salmonella dublin with porcine and bovine intestinal epithelia yielded no evidence to suggest that host restriction of s. choleraesuis and s. dublin for pigs and calves respectively could be explained in terms of the patterns of intestinal invasion observed in ligated ileal loops in vivo, at 3 h after challenge. no evidence was found to support the idea that peyer's patches, or specifically m cells, are the major route of ... | 1999 | 10517596 |
| identification of o-antigen polymerase transcription and translation start signals and visualization of the protein in salmonella enterica serovar typhimurium. | the wzy/rfc gene, encoding the o-antigen polymerase, of salmonella enterica serovar typhimurium has been previously cloned and sequenced. in the present work, the wzy transcriptional startpoint was initially identified by primer extension. next, wzy promoter strength in escherichia coli k-12 was measured, and was found to be greater than that of the induced lac promoter. to define the wzy translational startpoint, dna including the wzy promoter and the putative first five residues of the wzy pro ... | 1999 | 10517597 |
| multidrug-resistant salmonella associated with ampc hyperproduction. | 1999 | 10525002 | |
| analysis of virulence of clinical isolates of salmonella enteritidis in vivo and in vitro. | salmonella enterica serotype enteritidis (s. enteritidis) is a major food-borne pathogen, and its incidence among all salmonella serotypes has increased dramatically in the last two decades. to study the virulence characteristics of clinical isolates of s. enteritidis, we determined the 50% lethal doses (ld(50)) in mice of isolates of two major phage types (4 and 8). isolates of both phage types showed a wide range of ld(50) after oral inoculation, varying from under 10(2) organisms to over 10(8 ... | 1999 | 10531212 |
| analysis of salmonella enterica serotype typhimurium by phage typing, antimicrobial susceptibility and pulsed-field gel electrophoresis. | three typing methods commonly used for bacteria--phage typing, antimicrobial susceptibility and pulsed-field gel electrophoresis (pfge)- were used to characterise 64 salmonella enterica serotype typhimurium isolates from individual adult patients from nairobi, kenya. the isolates encompassed 11 definitive phage types (dts), which fell into eight pfge clusters; 31.3% of isolates were either untypable or reacted nonspecifically with the phages used for typing and 26.6% were of dt 56. plasmids of c ... | 1999 | 10535649 |
| colonisation of the chicken caecum by afimbriate and aflagellate derivatives of salmonella enterica serotype enteritidis. | a semi-quantitative cloacal-swab method was used as an indirect measure of caecal colonisation of one-day old and five-day old chicks after oral dosing with wild-type salmonella enterica serovar enteritidis pt4 and genetically defined isogenic derivatives lacking the ability to elaborate flagella or fimbriae. birds of both ages were readily and persistently colonised by all strains although there was a decline in shedding by the older birds after about 21 days. there were no significant differen ... | 1999 | 10535772 |
| activation of the cryptic aac(6')-iy aminoglycoside resistance gene of salmonella by a chromosomal deletion generating a transcriptional fusion. | salmonella enterica subsp. enterica serotype enteritidis bm4361 and bm4362 were isolated from the same patient. bm4361 was susceptible to aminoglycosides, whereas bm4362 was resistant to tobramycin owing to synthesis of a 6'-n-acetyltransferase type i [aac(6')-i]. comparative analysis of nucleotide sequences, pulsed-field gel electrophoresis patterns, and southern hybridizations indicated that the chromosomal aac(6')-iy genes for the enzyme in both strains were identical and that bm4362 derived ... | 1999 | 10542165 |
| potential of three-way randomly amplified polymorphic dna analysis as a typing method for twelve salmonella serotypes. | the potential of a three-way randomly amplified polymorphic dna (rapd) procedure (rapd typing) for typing salmonella enterica strains assigned to 12 serotypes was analyzed. the series of organisms used included 235 strains (326 isolates) collected mainly from clinical samples in the principality of asturias and 9 reference strains. rapd typing was performed directly with broth cultures of bacteria by using three selected primers and optimized pcr conditions. the profiles obtained with the three ... | 1999 | 10543793 |
| an outbreak of multidrug-resistant, quinolone-resistant salmonella enterica serotype typhimurium dt104. | food-borne salmonella infections have become a major problem in industrialized countries. the strain of salmonella enterica serotype typhimurium known as definitive phage type 104 (dt104) is usually resistant to five drugs: ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline. an increasing proportion of dt104 isolates also have reduced susceptibility to fluoroquinolones. | 1999 | 10547404 |
| hyporesponsiveness of the systemic and mucosal humoral immune systems in chickens infected with salmonella enterica serovar enteritidis at one day of age. | newly hatched chicks lack immunological maturity, which could compromise their ability to respond to infection by pathogens such as salmonella enterica serovar enteritidis (s. enteritidis; se). a study was conducted in which chicks were infected with a sublethal dose of se at 1 d posthatch, and the systemic and intestinal immune responses to the challenge were followed over time. birds infected at this age experienced difficulty in clearing the infection, and 50% of the individual birds remained ... | 1999 | 10560822 |
| genetic rearrangements in the tyrb-uvra region of the enterobacterial chromosome: a potential cause for different class b acid phosphatase regulation in salmonella enterica and escherichia coli. | unlike in escherichia coli, in salmonella enterica production of class b acid phosphatase (apha) was detectable also in cells growing in the presence of glucose. characterization of the apha locus from a s. enterica ser. typhi strain showed that the apha determinant is very similar to the e. coli homolog, and that its chromosomal location between the highly conserved tyrb and uvra genes is retained. however, the apha flanking regions were found to be markedly different in the two species, either ... | 1999 | 10564784 |
| harmonization of antibiotic susceptibility testing for salmonella: results of a study by 18 national reference laboratories within the european union-funded enter-net group. | for the effective surveillance of antimicrobial drug resistance within salmonella organisms from humans, harmonization of methods used for sensitivity testing by laboratories responsible for the typing of such organisms is essential. a study of resistance or sensitivity to a panel of 11 antimicrobials by the enter-net international surveillance network was therefore undertaken. there are 18 national salmonella reference laboratories within this european union-funded network. forty-eight strains ... | 1999 | 10566869 |
| identification of a putative salmonella enterica serotype typhimurium host range factor with homology to ipah and yopm by signature-tagged mutagenesis. | the genetic basis for the host adaptation of salmonella serotypes is currently unknown. we have explored a new strategy to identify salmonella enterica serotype typhimurium (s. typhimurium) genes involved in host adaptation, by comparing the virulence of 260 randomly generated signature-tagged mutants during the oral infection of mice and calves. this screen identified four mutants, which were defective for colonization of only one of the two host species tested. one mutant, which only displayed ... | 1999 | 10569754 |
| chlamydial lipopolysaccharide. | chlamydiae are obligatory intracellular parasites which are responsible for various acute and chronic diseases in animals and humans. the outer membrane of the chlamydial cell wall contains a truncated lipopolysaccharide (lps) antigen, which harbors a group-specific epitope being composed of a trisaccharide of 3-deoxy-d-manno-oct-2-ulosonic (kdo) residues of the sequence alpha-kdo-(2-->8)-alpha-kdo-(2-->4)-alpha-kdo. the chemical structure was established using lps of recombinant escherichia col ... | 1999 | 10571027 |
| prevalence of enterotoxin gene (stn) among different serovars of salmonella. | the prevalence of salmonella enterotoxin (stn) gene among different salmonella serovars by using polymerase chain reaction (pcr) and its status of expression on the chinese hamster ovary (cho) cells were investigated. all the 26 strains of salmonella enterica such as serovars typhimurium, enteritidis, dublin, typhi, newport, weltevreden, gallinarum, etc. investigated in this study were found to carry stn gene as examined by the pcr and gene probe. however, only a limited number of stn positive s ... | 1999 | 10573653 |
| dot-elisa for detection of salmonella enterotoxin. | nineteen strains of salmonella enterica belonging to seven serovars and two strains of s. bongori were investigated for enterotoxin production by the chinese hamster ovary (cho) cell assay and dot-elisa. all the 19 strains were found to carry stn gene when tested by polymerase chain reaction (pcr) using specific primers for stn sequence. thirteen strains (68.42%) were found to produce salmonella enterotoxin (stn) when tested by the cho cell assay. dot-elisa could detect stn in 16 strains (84.21% ... | 1999 | 10573654 |
| the activity of a putative polyisoprenol-linked sugar translocase (wzx) involved in escherichia coli o antigen assembly is independent of the chemical structure of the o repeat. | during o antigen lipopolysaccharide (lps) synthesis in bacteria, transmembrane migration of undecaprenylpyrophosphate (und-p-p)-bound o antigen subunits occurs before their polymerization and ligation to the rest of the lps molecule. despite the general nature of the translocation process, putative o-antigen translocases display a low level of amino acid sequence similarity. in this work, we investigated whether complete o antigen subunits are required for translocation. we demonstrate that a si ... | 1999 | 10574995 |
| epidemiology of salmonella enterica serotype enteritidis in southern italy in the period january 1995-june 1998. | 1999 | 10596426 | |
| [the epidemiology of salmonella enterica serotype enteritidis in southern italy in 1980-98: the contribution of molecular typing]. | 1999 | 10596439 | |
| [increase of bacterial resistance in human medicine by resistance genes of bacteria from meat supplying animals]. | two different groups of bacteria carrying genes encoding for resistance to antibiotics may be transmitted from animals to humans via food products: a.) obligate infectious agents (enteric pathogens, e.g. salmonella enterica spp., campylobacter spp., ehec) and b) facultative pathogenic species (e.g. e. coli, enterococci). thus far, it is unknown whether genes encoding for resistance to antibiotics from these bacteria may be transferred to bacteria in normal flora of the host. the transfers of gen ... | 1999 | 10598355 |
| a novel integron in salmonella enterica serovar enteritidis, carrying the bla(dha-1) gene and its regulator gene ampr, originated from morganella morganii. | the genetic organization of the gene coding for dha-1 and the corresponding ampr gene was determined by pcr mapping. these genes have been mobilized from the morganella morganii chromosome and inserted into a complex suli-type integron, similar to in6 and in7. however, they are not themselves mobile cassettes. this integron probably includes a specific site for recombination allowing the mobilization of diverse resistance genes, as observed for bla(cmy-1) and bla(mox-1). | 2000 | 10602756 |
| changes in antimicrobial resistance among salmonella enterica serovar typhimurium isolates from humans and cattle in the northwestern united states, 1982-1997. | we compared antimicrobial resistance patterns of salmonella enterica serovar typhimurium (st) of isolates from humans (n = 715) and cattle (n = 378) in the pacific northwest from 1982 through 1997. the major changes in antimicrobial resistance can be attributed to the widespread clonal dissemination of multidrug-resistant definitive phage type 104 st. | 1999 | 10603215 |
| igh-6(-/-) (b-cell-deficient) mice fail to mount solid acquired resistance to oral challenge with virulent salmonella enterica serovar typhimurium and show impaired th1 t-cell responses to salmonella antigens. | in the present study we evaluated the role of b cells in acquired immunity to salmonella infection by using gene-targeted b-cell-deficient innately susceptible mice on a c57bl/6 background (igh-6(-/-)). igh-6(-/-) mice immunized with a live, attenuated aroa salmonella enterica serovar typhimurium vaccine strain showed impaired long-term acquired resistance against the virulent serovar typhimurium strain c5. igh-6(-/-) mice were able to control a primary infection and to clear the inoculum from t ... | 2000 | 10603367 |
| in vivo characterization of the murine intranasal model for assessing the immunogenicity of attenuated salmonella enterica serovar typhi strains as live mucosal vaccines and as live vectors. | attenuated salmonella enterica serovar typhi live vector vaccine strains are highly immunogenic in mice following intranasal but not orogastric inoculation. to elucidate the relationship between organs within which vaccine organisms are found and the induction of specific serum immunoglobulin g (igg) antibodies, we examined the in vivo distribution of serovar typhi vaccine strain cvd 908-htra following intranasal administration. vaccine organisms were cultured from the nasal lymphoid tissue (nal ... | 2000 | 10603389 |
| clonal relationship of salmonella enterica serovar typhimurium phage type dt104 in germany and austria. | a new epidemic clone of salmonella enterica serovar typhimurium designated definitive phage type (dt) 104 has been emerging since 1990 to become most common type among s. typhimurium isolates in germany and austria. molecular fingerprinting (pfge-pattern, plasmid profiles, is200 pattern, ribotype, eric-type, omp and mle patterns) revealed the majority of the dt104 isolates to have clonal identity; they were designated as type 1 (about 95%). moreover, clonal type 1 of dt104 was found to occur in ... | 1999 | 10603659 |
| mucosal competitive exclusion to reduce salmonella in swine. | a mucosal competitive exclusion culture has been shown to reduce or eliminate salmonella spp. in poultry. using similar techniques, a mucosal competitive exclusion culture from swine (mces) was produced from the cecum of a 6-week-old pig. suckling pigs were inoculated with 5 ml of mces by oral gavage within 6 h postfarrowing (pf) and again at 24 h pe all pigs were challenged with 10(3) cfu of salmonella choleraesuis at 48 h pf by intranasal instillation, including pigs from two sows that had not ... | 1999 | 10606140 |
| identification of soxs-regulated genes in salmonella enterica serovar typhimurium. | salmonella enterica serovar typhimurium responds to superoxide-generating agents through soxr-mediated activation of the soxs gene, whose product, soxs, is necessary for resistance to oxidative stress. the s. enterica serovar typhimurium soxrs system also mediates redox-inducible resistance to diverse antibiotics, which may be relevant to clinical infections. in order to identify soxs-regulated genes in s. enterica serovar typhimurium, a laci-regulated expression system for the s. enterica serov ... | 2000 | 10613858 |
| proline catabolism by pseudomonas putida: cloning, characterization, and expression of the put genes in the presence of root exudates. | pseudomonas putida kt2442 is a root-colonizing strain which can use proline, one of the major components in root exudates, as its sole carbon and nitrogen source. a p. putida mutant unable to grow with proline as the sole carbon and nitrogen source was isolated after random mini-tn5-km mutagenesis. the mini-tn5 insertion was located at the puta gene, which is adjacent to and divergent from the putp gene. the puta gene codes for a protein of 1,315 amino acid residues which is homologous to the pu ... | 2000 | 10613867 |
| lesions in the nuo operon, encoding nadh dehydrogenase complex i, prevent purf-independent thiamine synthesis and reduce flux through the oxidative pentose phosphate pathway in salmonella enterica serovar typhimurium. | in salmonella enterica serovar typhimurium, purf-independent thiamine synthesis (or alternative pyrimidine biosynthesis) allows strains, under some growth conditions, to synthesize thiamine in the absence of the first step in the purine biosynthetic pathway. mutations have been isolated in a number of loci that prevent this synthesis and thus result in an apb(-) phenotype. here we identify a new class of mutations that prevent purf-independent thiamine synthesis and show that they are defective ... | 2000 | 10613887 |
| reduced flux through the purine biosynthetic pathway results in an increased requirement for coenzyme a in thiamine synthesis in salmonella enterica serovar typhimurium. | work presented here establishes a connection between cellular coenzyme a (coa) levels and thiamine biosynthesis in salmonella enterica serovar typhimurium. prior work showed that pane mutants (pane encodes ketopantoate reductase) had a conditional requirement for thiamine or pantothenate. data presented herein show that the nutritional requirement of pane mutants for either thiamine or pantothenate is manifest only when flux through the purine biosynthetic pathway is reduced. further, the data s ... | 2000 | 10613889 |
| molecular methods for the epidemiological typing of salmonella enterica serotype typhi from hong kong and vietnam. | a total of 217 and 73 strains of salmonella enterica serotype typhi isolated from 1985 to 1997 in hong kong and in 2 months of 1989 and 1990 in vietnam, respectively, were studied. these isolates were typed by plasmid profile analysis, plasmid fingerprinting, ribotyping with psti, and total dna fingerprinting with nari. there appeared to be no major outbreak of typhoid fever in hong kong during the study period since there was considerable heterogeneity among the isolates. isolates from hong kon ... | 2000 | 10618104 |
| evolutionary reversals during viral adaptation to alternating hosts. | experimental adaptation of the bacteriophage phix174 to a salmonella host depressed its ability to grow on the traditional escherichia host, whereas adaptation to escherichia did not appreciably affect growth on salmonella. continued host switching consistently exhibited this pattern. growth inhibition on escherichia resulted from two to three substitutions in the major capsid gene. when these phages were forced to grow again on escherichia, fitness recovery occurred predominantly by reversions ... | 2000 | 10628966 |
| the rfae gene from escherichia coli encodes a bifunctional protein involved in biosynthesis of the lipopolysaccharide core precursor adp-l-glycero-d-manno-heptose. | the intermediate steps in the biosynthesis of the adp-l-glycero-d-manno-heptose precursor of inner core lipopolysaccharide (lps) are not yet elucidated. we isolated a mini-tn10 insertion that confers a heptoseless lps phenotype in the chromosome of escherichia coli k-12. the mutation was in a gene homologous to the previously reported rfae gene from haemophilus influenzae. the e. coli rfae gene was cloned into an expression vector, and an in vitro transcription-translation experiment revealed a ... | 2000 | 10629197 |
| the amino terminus of salmonella enterica serovar typhimurium sigma(54) is required for interactions with an enhancer-binding protein and binding to fork junction dna. | transcription initiation by the sigma(54)-rna polymerase holoenzyme requires an enhancer-binding protein that is thought to contact sigma(54) to activate transcription. to identify potential enhancer-binding protein contact sites in sigma(54), we compared the abilities of wild-type and truncated forms of salmonella enterica serovar typhimurium sigma(54) to interact with the enhancer-binding protein dctd in a chemical cross-linking assay. removal of two regions in the amino-terminal portion of si ... | 2000 | 10629201 |
| opda, a salmonella enterica serovar typhimurium gene encoding a protease, is part of an operon regulated by heat shock. | the opda (prlc) gene of salmonella enterica serovar typhimurium and escherichia coli encodes the metalloprotease oligopeptidase a (opda). we report that opda is cotranscribed with a downstream open reading frame, yhiq. transcription of this operon is induced after a temperature shift (30 to 42 degrees c), and this induction depends on the heat shock sigma factor encoded by the rpoh (htpr) gene. | 2000 | 10629202 |
| expression and immunogenicity of hemagglutinin a from porphyromonas gingivalis in an avirulent salmonella enterica serovar typhimurium vaccine strain. | porphyromonas gingivalis is a major etiologic agent of periodontitis, a chronic inflammatory disease that ultimately results in the loss of the supporting tissues of the teeth. previous work has demonstrated the usefulness of avirulent salmonella enterica serovar typhimurium strains as antigen delivery systems for protective antigens of pathogens that colonize or cross mucosal surfaces. in this study, we constructed and characterized a recombinant s. enterica serovar typhimurium avirulent vaccin ... | 2000 | 10639440 |
| impact of heterogeneity within cultured cells on bacterial invasion: analysis of pseudomonas aeruginosa and salmonella enterica serovar typhi entry into mdck cells by using a green fluorescent protein-labelled cystic fibrosis transmembrane conductance regulator receptor. | the cystic fibrosis transmembrane conductance regulator (cftr) is a chloride ion channel that also serves as a receptor for entry of pseudomonas aeruginosa and salmonella enterica serovar typhi into epithelial cells. to evaluate heterogeneity in cftr protein expression in cultured cells and the effect of heterogeneity on internalization of different p. aeruginosa and serovar typhi strains, we used two-color flow cytometry and confocal laser microscopy to study bacterial uptake by madin-darby can ... | 2000 | 10639456 |
| use of lambda phage s and r gene products in an inducible lysis system for vibrio cholerae- and salmonella enterica serovar typhimurium-based dna vaccine delivery systems. | novel methods for adapting dna vaccine technology to the prevention of mucosal diseases are greatly needed. here we show that regulated expression of phage lambda lysis genes s and r causes dramatic lysis of both vibrio cholerae and salmonella enterica serovar typhimurium cells with concomitant release of plasmid dna into the surrounding media. we also used single and double dnase mutant strains to show that secreted v. cholerae dnases can adversely affect the integrity of dna molecules released ... | 2000 | 10639478 |
| the salmonella yopj-homologue avra does not possess yopj-like activity. | the yopj protein of yersinia pseudotuberculosis inhibits several eukaryotic signalling pathways that are normally activated in cells following their contact with bacteria. salmonella encodes a protein, avra, that is secreted by the typeiii inv/spa secretion system which is clearly homologous to yopj (56% identical, 87% similarity). since avra and yopjs similarity also encompassed a region of yopj that had previously been shown to be critical for its biological activity, we were interested whethe ... | 2000 | 10644492 |
| genetic and biochemical characterization of salmonella enterica serovar typhi deoxyribokinase. | we identified in the genome of salmonella enterica serovar typhi the gene encoding deoxyribokinase, deok. two other genes, vicinal to deok, were determined to encode the putative deoxyribose transporter (deop) and a repressor protein (deoq). this locus, located between the uhpa and ilvn genes, is absent in escherichia coli. the deok gene inserted on a plasmid provides a selectable marker in e. coli for growth on deoxyribose-containing medium. deoxyribokinase is a 306-amino-acid protein which exh ... | 2000 | 10648508 |
| prpr, ntra, and ihf functions are required for expression of the prpbcde operon, encoding enzymes that catabolize propionate in salmonella enterica serovar typhimurium lt2. | the genes required for the catabolism of propionate in salmonella enterica serovar typhimurium are organized as two transcriptional units (prpr and prpbcde) that are divergently transcribed from one another. sequence homology to genes encoding members of the sigma-54 family of transcriptional activators and the identification of a consensus sigma-54 promoter 5' to the prpbcde operon suggested that prpr was required to activate expression of this operon. we isolated insertions in prpr and showed ... | 2000 | 10648513 |
| insertional inactivation of genes encoding components of the sodium-type flagellar motor and switch of vibrio parahaemolyticus. | vibrio parahaemolyticus possesses two types of flagella, polar and lateral, powered by distinct energy sources, which are derived from the sodium and proton motive forces, respectively. although proton-powered flagella in escherichia coli and salmonella enterica serovar typhimurium have been extensively studied, the mechanism of torque generation is still not understood. molecular knowledge of the structure of the sodium-driven motor is only now being developed. in this work, we identify the swi ... | 2000 | 10648530 |
| fragmentation of 23s rrna in strains of proteus and providencia results from intervening sequences in the rrn (rrna) genes. | intervening sequences (ivss) were originally identified in the rrl genes for 23s rrna (rrl genes, for large ribosomal subunit, part of rrn operon encoding rrna) of salmonella enterica serovars typhimurium lt2 and arizonae. these sequences are transcribed but later removed during rnase iii processing of the rrna, resulting in fragmentation of the 23s species; ivss are uncommon, but have been reported in at least 10 bacterial genera. through pcr amplification of ivs-containing regions of the rrl g ... | 2000 | 10648538 |
| [necrotizing pneumonia due to salmonella sp. complicated by pneumothorax in a patient infected with the human immunodeficiency virus]. | 1999 | 10650658 | |
| genetically modified vibrio harveyi strains as potential bioindicators of mutagenic pollution of marine environments. | for biodetection of mutagenic pollution of marine environments, an organism naturally occurring in these habitats should be used. we found that marine bacterium vibrio harveyi may be an appropriate bioindicator of mutagenic pollution. for positive selection of mutants, we developed a simple method for isolation of v. harveyi mutants resistant to neomycin. we constructed genetically modified v. harveyi strains that produce significantly more neomycin-resistant mutants upon treatment with low conc ... | 2000 | 10653723 |
| molecular characterization of irish salmonella enterica serotype typhimurium: detection of class i integrons and assessment of genetic relationships by dna amplification fingerprinting. | salmonella enterica is among the principal etiological agents of food-borne illness in humans. increasing antimicrobial resistance in s. enterica is a cause for worldwide concern. there is concern at present in relation to the increasing incidence of human infection with antimicrobial agent-resistant strains of s. enterica serotype typhimurium, in particular of phage type dt104. integrons appear to play an important role in the dissemination of antimicrobial resistance genes in many enterobacter ... | 2000 | 10653725 |
| epidemic typhoid in vietnam: molecular typing of multiple-antibiotic-resistant salmonella enterica serotype typhi from four outbreaks. | multidrug-resistant salmonella enterica serotype typhi isolates from four outbreaks of typhoid fever in southern vietnam between 1993 and 1997 were compared. pulsed-field gel electrophoresis, bacteriophage and plasmid typing, and antibiotic susceptibilities showed that independent outbreaks of multidrug-resistant typhoid fever in southern vietnam are caused by single bacterial strains. however, different outbreaks do not derive from the clonal expansion of a single multidrug-resistant serotype t ... | 2000 | 10655411 |
| a role for salmonella fimbriae in intraperitoneal infections. | enteric bacteria possess multiple fimbriae, many of which play critical roles in attachment to epithelial cell surfaces. sef14 fimbriae are only found in salmonella enterica serovar enteritidis (s. enteritidis) and closely related serovars, suggesting that sef14 fimbriae may affect serovar-specific virulence traits. despite evidence that sef14 fimbriae are expressed by s. enteritidis in vivo, previous studies showed that sef14 fimbriae do not mediate adhesion to the intestinal epithelium. theref ... | 2000 | 10655518 |
| antimicrobial activity of home disinfectants and natural products against potential human pathogens. | to assess the efficacy of both natural products (vinegar, baking soda) and common commercial disinfectants (vesphene iise, tbq, clorox, lysol disinfectant spray, lysol antibacterial kitchen cleaner, mr. clean ultra, ethanol) designed for home or institutional use against potential human pathogens, including selected antibiotic-resistant bacteria. | 2000 | 10656352 |
| comparative pathology of bacterial enteric diseases of swine. | enteric bacterial infections are among the most common and economically significant diseases affecting swine production worldwide. clinical signs of these infections include diarrhea, reduced growth rate, weight loss, and death of preweaned, weanling, grower-finisher, young and adult age breeding animals. the most common etiological agents include escherichia coli, clostridium perfringens, lawsonia intracellularis, salmonella enterica, and brachyspira (serpulina) spp. with the exception of brach ... | 1999 | 10659346 |
| norepinephrine stimulates in vitro growth but does not increase pathogenicity of salmonella choleraesuis in an in vivo model. | norepinephrine stimulates growth of escherichia coli, yersinia enterocolitica, and pseudomonas aeruginosa in serum-supplemented media, and in vivo increases in norepinephrine may be important in the pathogenesis of sepsis by gram-negative bacteria. because salmonellosis often is associated with stress, the effects of norepinephrine on in vitro growth, and in vivo pathogenicity of the swine pathogen salmonella choleraesuis were investigated. when rpmi 1640 with and without pig serum was inoculate ... | 1999 | 10659366 |
| prophylactic administration of immune lymphokine derived from t cells of salmonella enteritidis-immune pigs. protection against salmonella choleraesuis organ invasion and cecal colonization in weaned pigs. | experiments involving 132 weaned piglets were conducted to evaluate the efficacy of a salmonella enteritidis-immune lymphokine (pilk) derived from the t cells of salmonella enteritidis (se)-immunized pigs to protect weaned piglets from salmonella choleraesuis (sc) infection. fourteen-to-seventeen day-old piglets were weaned and randomly placed into 1 of 5 groups: (1) noninfected controls, (2) pilk 3x noninfected, (3) sc infected controls, (4) pilk 1x sc infected, and (5) pilk 3x sc infected. pil ... | 1999 | 10659371 |
| predictors for extraintestinal infection of non-typhoidal salmonella in patients without aids. | to identify the risks and predictors for extraintestinal infection (eii) in patients with non-typhoidal salmonellosis, we undertook a study of 398 patients with cultures positive for non-typhoidal salmonella seen at chang gung memorial hospital and chang gung children's hospital between november 1993 and october 1994. salmonella choleraesuis was the most invasive serotype observed. s. panama, s. typhimurium and s. schwarzengrund were the commonest causes of eii among those serotypes usually caus ... | 1999 | 10665125 |
| overexpression, purification, crystallization and preliminary structural study of dtdp-6-deoxy-l-lyxo-4-hexulose reductase (rmld), the fourth enzyme of the dtdp-l-rhamnose synthesis pathway, from salmonella enterica serovar typhimurium. | l-rhamnose is an essential component of the cell wall of many pathogenic bacteria. its precursor, dtdp-l-rhamnose, is synthesized from alpha-d-glucose-1-phosphate and dttp via a pathway requiring four distinct enzymes: rmla, rmlb, rmlc and rmld. rmld catalyses the terminal step of this pathway by converting dtdp-6-deoxy-l-lyxo-4-hexulose to dtdp-l-rhamnose. rmld from -salmonella enterica serovar typhimurium has been overexpressed in escherichia coli. the recombinant protein was purified by a two ... | 1999 | 10666586 |
| the purification, crystallization and structural elucidation of dtdp-d-glucose 4,6-dehydratase (rmlb), the second enzyme of the dtdp-l-rhamnose synthesis pathway from salmonella enterica serovar typhimurium. | dtdp-d-glucose 4,6-dehydratase (rmlb) is the second of four enzymes involved in the dtdp-l-rhamnose pathway and catalyzes the dehydration of dtdp-d-glucose to dtdp-4-keto-6-deoxy-d-glucose. the ultimate product of the pathway, dtdp-l-rhamnose, is the precursor of l-rhamnose, which is a key component of the cell wall of many pathogenic bacteria. rmlb from salmonella enterica serovar typhimurium has been overexpressed and purified, and crystals of the enzyme have been grown using the sitting-drop ... | 2000 | 10666612 |
| salmonella enteritidis fimbriae displaying a heterologous epitope reveal a uniquely flexible structure and assembly mechanism. | two distinct salmonella fimbrins, agfa and sefa, comprising thin aggregative fimbriae sef17 and sef14, respectively, were each genetically engineered to carry pt3, an alpha-helical 16-amino acid leishmania t-cell epitope derived from the metalloprotease gp63. to identify regions within agfa and sefa fimbrins amenable to replacement with this epitope, pcr-generated chimeric fimbrin genes were constructed and used to replace the native chromosomal agfa and sefa genes in salmonella enteritidis. imm ... | 2000 | 10669594 |
| novel missense mutations that affect the transport function of malk, the atp-binding-cassette subunit of the salmonella enterica serovar typhimurium maltose transport system. | we report on novel mutations in the malk gene of salmonella enterica serovar typhimurium, encoding the atpase subunit of the maltose transporter (malfgk(2)). biochemical analysis suggests that (i) l86 might be involved in a signaling step during substrate translocation and (ii) e306 may be critical for the structural integrity of the protein. | 2000 | 10671470 |
| mutational analysis of ligand recognition by tcp, the citrate chemoreceptor of salmonella enterica serovar typhimurium. | the chemoreceptor tcp mediates taxis to citrate. to identify citrate-binding residues, we substituted cysteine for seven basic or polar residues that are chosen based on the comparison of tcp with the well-characterized chemoreceptors. the results suggest that arg-63, arg-68, arg-72, lys-75, and tyr-150 (and probably other unidentified residues) are involved in the recognition of citrate. | 2000 | 10671471 |
| solvent accessibility and purifying selection within proteins of escherichia coli and salmonella enterica. | the neutral theory of molecular evolution predicts that variation within species is inversely related to the strength of purifying selection, but the strength of purifying selection itself must be related to physical constraints imposed by protein folding and function. in this paper, we analyzed five enzymes for which polymorphic sequence variation within escherichia coli and/or salmonella enterica was available, along with a protein structure. single and multivariate logistic regression models ... | 2000 | 10677853 |
| differential bacterial survival, replication, and apoptosis-inducing ability of salmonella serovars within human and murine macrophages. | salmonella serovars are associated with human diseases that range from mild gastroenteritis to host-disseminated enteric fever. human infections by salmonella enterica serovar typhi can lead to typhoid fever, but this serovar does not typically cause disease in mice or other animals. in contrast, s. enterica serovar typhimurium and s. enterica serovar enteritidis, which are usually linked to localized gastroenteritis in humans and some animal species, elicit a systemic infection in mice. to bett ... | 2000 | 10678900 |
| salmonella enterica serovar typhimurium sura mutants are attenuated and effective live oral vaccines. | a previously described attenuated tnphoa mutant (brd441) of salmonella enterica serovar typhimurium c5 (i. miller, d. maskell, c. hormaeche, k. johnson, d. pickard, and g. dougan, infect. immun. 57:2758-2763, 1989) was characterized, and the transposon was shown to be inserted in sura, a gene which encodes a peptidylprolyl-cis, trans-isomerase. a defined sura deletion mutation was introduced into s. enterica serovar typhimurium c5 and the mutant strain, named s. enterica serovar typhimurium brd1 ... | 2000 | 10678914 |
| phase 2 clinical trial of attenuated salmonella enterica serovar typhi oral live vector vaccine cvd 908-htra in u.s. volunteers. | salmonella enterica serovar typhi strain cvd 908-htra is a live attenuated strain which may be useful as an improved oral typhoid vaccine and as a vector for cloned genes of other pathogens. we conducted a phase 2 trial in which 80 healthy adults received one of two dosage levels of cvd 908-htra in a double-blind, placebo-controlled, crossover study. there were no differences in the rates of side effects among volunteers who received high-dose vaccine (4.5 x 10(8) cfu), lower-dose vaccine (5 x 1 ... | 2000 | 10678926 |
| phase 1 and phase 2 studies of salmonella enterica serovar paratyphi a o-specific polysaccharide-tetanus toxoid conjugates in adults, teenagers, and 2- to 4-year-old children in vietnam. | salmonella enterica serovar paratyphi a o-specific polysaccharide (o-sp) was activated with 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (cdap) and bound to tetanus toxoid (tt) with adipic acid dihydrazide as a linker (spa-tt(1)) or directly (spa-tt(2)). in mice, these two conjugates elicited high levels of immunoglobulin g (igg) anti-lipopolysaccharide (lps) in serum with bactericidal activity (e. konadu, j. shiloach, d. a. bryla, j. b. robbins, and s. c. szu, infect. immun. 64:2709-2715 ... | 2000 | 10678970 |