| lactulose therapy in shigella carrier state and acute dysentery. | antibiotic-resistant shigella are increasingly prevalent. lactulose, a non-absorbable disaccharide, was investigated as an alternative therapy for shigella infection on the hypothesis that the short-chain fatty acids (inhibitory to shigella) resulting from metabolism of lactulose by normal colonic flora would diminish shigella excretion. a long-term antibiotic-refractory carrier (large bowel) excreting 10(4) to 10(7)shigella sonnei/g of feces was given two courses of lactulose (of 24 and 16 days ... | 1975 | 2098 |
| shigella infection of henle intestinal epithelial cells: role of the host cell. | the process of henle 407 embryonic intestinal epithelial cell infection by shigella flexneri 2a m42-43 was studied in an in vitro model system. the role of the henle cell was assessed. it was established that entry of s. flexneri into cells was suppressed by reagents which inhibit uptake of particles by phagocytic cells. the compounds tested included cytochalasin b, dibutyryl-cyclic adenosine monophosphate, choleragen (vibrio cholera enterotoxin), iodoacetate, and dinitrophenol. cytochalasin b i ... | 1979 | 223988 |
| reiter's syndrome following shigella flexneri 2a: a sequel to traveler's diarrhea. report of a case with hepatitis. | shigella flexneri 2a was isolated from a patient with reiter's syndrome (rs) following a family outbreak of traveler's diarrhea. among 3 members at risk, only the patient was positive for hla-b27. data from 3 similar families support the hypothesis that susceptibility to rs is genetically transmitted. it is urged that every effort be made to culture and subtype shigella and other enteric pathogens in rs following diarrhea. concurrently, the patient had hepatitis, interpreted as a parallel enteri ... | 1977 | 319805 |
| biological properties of shigella flexneri 2a toxin and its serological relationship to shigella dysenteriae 1 toxin. | a toxin extracted from heat-inactivated, alkaline-treated shigella flexneri 2a showed biological properties similar to those of shigella dysenteria 1 toxin. the s, flexneri 2a toxin was lethal to mice, enterotoxic for ileal loops of rabbits, and cytotoxic for hela cells. a serological relationship between s. flexneri 2a and s. dysenteriae 1 toxin was shown with cross neutralization tests. | 1977 | 323142 |
| phagocytosis stimulation by an extracellular product of virulent shigella flexneri 2a. | | 1977 | 323646 |
| rough mutant of shigella flexneri 2a that penetrates tissue culture cells but does not evoke keratoconjunctivitis in guinea pigs. | a rough mutant, designated 5503-01, has been isolated from a virulent strain of shigella flexneri 2a 5503. strain 5503-01 produced smooth opaque colonies, whereas its parent strain produced characteristic green-gold translucent ones. characterization of 5503-01 by agglutination tests, rhamnose content, and sensitivity spectra to "rough-specific" phages revealed that it had lost the specific somatic antigens. when 5503-01 was used to infect hela or l cells, it penetrated the cells and multiplied ... | 1977 | 328396 |
| studies with a new generation of oral attenuated shigella vaccine: escherichia coli bearing surface antigens of shigella flexneri. | in an attempt to develop a safe, proliferating, oral, attenuated vaccine against shigellosis, genes that control the synthesis of group- and type-specific somatic antigens of shigella flexneri 2a were transferred via conjugation to a recipient strain of escherichia coli. the resultant hybrid (e. coli expressing shigella surface antigens) vaccine strain, pgai 42-1-15, believed to have a complete (smooth) lipopolysaccharide, was given to volunteers in two vaccination-challenge studies. the vaccine ... | 1977 | 333041 |
| a possible role of glycolipids in epithelial cell penetration by virulent shigella flexneri 2a. | | 1977 | 333234 |
| shigella infection of henle intestinal epithelial cells: role of the bacterium. | epithelial cell infection by shigella flexneri 2a was studied in an in vitro model system. using the henle 407 human intestinal epithelial cell line as host cells, a standardized experimental protocol which allowed quantitative measurement of infection was developed. intravellular residence of infecting organisms was confirmed by indirect fluorescent-antibody staining of unfixed and methanol-fixed (henle 407) cells and by quantitative bacteriological culture of disrupted host cells after infecti ... | 1979 | 381204 |
| [intestinal flora and bile acids metabolism -- influence of bile acids on rejection of shigella flexneri 2a from the intestine (author's transl)]. | | 1979 | 392126 |
| [studies concerning dysenteric infections in a closed children's community before and after antidysenteric vaccination. i. epidemiological considerations on acute intestinal infections]. | in the closed children's community studied between 1 jan. 1976 and 13 june 1977, a high proportion (54%) of the total number of acute intestinal infections was of dysenteric etiology, i.e. 46,9% in the 0--1 year age-group and 21,1% in the 1--3 years age-group, the dominant shigella subtype being represented by shigella flexneri 2a (25.1%). as only 37.2% of the total number of dysentery cases were manifested by enterocolitis and a high proportion (33.3%) ran a chronic course, the disease was not ... | 1979 | 394271 |
| the cellular and humoral immune response after administration to the guinea pig of shigella flexneri 2a t32--istrati vaccinal strain by different routes. | | 1978 | 395927 |
| oral immunization of monkeys with polyvalent dysentery vaccine. | macaca mulatta monkeys were immunized orally with polyvalent boivin extract of shigella flexneri 2a, 3a, 4a, 4b, 6 and shigella sonnei. the total immumizing dose for each component was equivalent to 1.2 x 10(12) cells. after challenge with 7.5 x 10(10) cells of a virulent s. flexneri 2a strain, out of 20 immunized animals 2 developed dysentery and 4 showed mild dyspepsia; all 6 control animals became ill with dysentery. vaccination failed to influence the incidence, duration or the intermittent ... | 1977 | 412396 |
| fecal steroids in diarrhea. i. acute shigellosis. | fecal bile acid and neutral sterol patterns of five healthy adult male volunteers, who were challenged by a virulent shigella flexneri 2a (m42-43) strain and developed dysentery were studied. it was observed that cholic acid was increased from 1.9 +/- 0.4% of total bile acid in the feces before infection to 14.5 +/- 2.1% during diarrhea (p less than 0.001). chenodeoxycholic acid also was increased from 3.2 +/- 0.7 to 8.7 +/- 3.2% in diarrhea but the difference was not significant statistically. ... | 1976 | 786002 |
| divalent cation stimulation of the cell infectivity of shigella flexneri 2a. | | 1975 | 807763 |
| fluid and electrolyte transport in rhesus monkeys challenged intracecally with shigella flexneri 2a. | shigella flexneri 2a is an invasive enteric pathogen that may produce diarrhea when ingested by human beings and subhuman primates. we have previously shown that shigella diarrhea correlates with water and electrolyte transport abnormalities in the jejunum and colon. dysentery alone is associated only with colonic transport abnormalities. to define the relationship between invasion and inflammation of the colon and the occurrence of jejunal transport abnormalities, we studied water and electroly ... | 1976 | 823110 |
| pathophysiology of shigella diarrhea in the rhesus monkey: intestinal transport, morphological, and bacteriological studies. | in contrast to the "toxigenic diarrheas" caused by vibrio cholerae and escherichia coli, the site and mechanism of fluid loss in shigellosis are unknown. the occurrence of watery diarrhea in shigellosis suggests involvement of the small bowel. therefore, jejunal, ileal, and colonic water and electrolyte transport was studied in shigella flexneri 2a-infected monkeys. infected animals fell into three groups: dysentery alone, diarrhea alone, or diarrhea and dysentery. in controls, net water, sodium ... | 1975 | 1090480 |
| transfer of e1 and v colicinogenic factors to shigella flexneri. | from escherichia coli strains, cole1-ml and colv-k94 factors were transferred to a virulent shigella flexneri 2a strain at 1-2% frequency. s. flexneri colv+ and cole1+v+ produced col- segregants. the cole1 factor was stably incorporated into s. flexneri. the colv+ culture lost its virulence to the guinea pig eye. | 1975 | 1092133 |
| [biochemical and genetic characteristics of enteropathogenic escherichia coli and shigella. v. the biological properties of auxotrophic mutants of shigella flexneri 2a and of escherichia coli serogroup 0124:k72]. | | 1975 | 1108515 |
| spontaneous insertion of an is1-like element into the virf gene is responsible for avirulence in opaque colonial variants of shigella flexneri 2a. | colonial variation of shigella flexneri serotype 2a from the translucent (2457t) to the opaque form (2457o) occurs spontaneously once in 10(4) cell divisions, with concomitant loss of ipa gene expression and virulence. the appearance of 2457o was associated with the insertional inactivation of virf, an invasion plasmid-encoded positive regulator of ipa gene expression. plasmid pwr110, a tn5-tagged invasion plasmid that restores the invasive phenotype to plasmid-cured shigella derivatives, was co ... | 1992 | 1309511 |
| vacb, a novel chromosomal gene required for expression of virulence genes on the large plasmid of shigella flexneri. | shigellae, the causative agents of bacillary dysentery, are capable of adhering to and invading epithelial cells and spreading into adjacent cells. a chromosomal mutant of shigella flexneri 2a ysh6000 with reduced invasive capacity was isolated by tn5 insertion mutagenesis. the linkage of the mutant phenotype to the tn5 insertion was determined by p1 phage transduction. the site of the tn5 insertion was assigned to a noti chromosomal restriction map, confirming that the virulence-associated locu ... | 1992 | 1400189 |
| identification and characterization of virk, a virulence-associated large plasmid gene essential for intercellular spreading of shigella flexneri. | seven virulence loci have been identified by tn5 insertion mutagenesis on the large 230 kb plasmid (pmysh6000) of shigella flexneri 2a. in this study, we used tn10 insertion mutagenesis and identified a novel virulence locus on pmysh6000 responsible for bacterial spread. characterization of the invading bacteria of the tn10 insertion mutants in the epithelial cells revealed that the bacteria were capable of at least some intracellular spreading but not intercellular spreading. immunoblot analysi ... | 1992 | 1406277 |
| presence of specific immunoglobulin a-secreting cells in peripheral blood after natural infection with shigella sonnei. | the appearance of antigen-specific immunoglobulin a (iga) antibody-secreting cells (ascs) following natural infection with shigella sonnei during a common-source outbreak caused by this organism was evaluated in a modified enzyme-linked immunosorbent assay (elispot). a mean iga asc value of 2,131.6/10(6) cells against homologous s. sonnei lipopolysaccharide (lps) was detected in blood samples obtained from patients with bacteriologically proven s. sonnei shigellosis 5 and 10 days after the onset ... | 1992 | 1500527 |
| safety, immunogenicity, and efficacy in monkeys and humans of invasive escherichia coli k-12 hybrid vaccine candidates expressing shigella flexneri 2a somatic antigen. | a live, oral shigella vaccine, constructed by transfer of the 140-mda invasiveness plasmid from shigella flexneri 5 and the chromosomal genes encoding the group- and type-specific o antigen of s. flexneri 2a to escherichia coli k-12, was tested in humans. designated ecsf2a-1, this vaccine produced adverse reactions (fever, diarrhea, or dysentery) in 4 (31%) of 13 subjects who ingested a single dose of 1.0 x 10(9) cfu, while at better-tolerated doses (5.0 x 10(6) to 5.0 x 10(7) cfu), it provided ... | 1992 | 1587589 |
| age-specific prevalence of serum antibodies to the invasion plasmid and lipopolysaccharide antigens of shigella species in chilean and north american populations. | shigella species have virulence plasmids that encode outer membrane proteins (invasion plasmid antigens, ipa) associated with pathogenicity. western blots were used to detect antibodies to ipa in sera from 390 chilean children, and these responses were compared with those of a us population of infants and adults. antibodies to lipopolysaccharide (lps) of plesiomonas shigelloides and shigella flexneri 2a were measured by elisa. among the chileans, there was an age-related acquisition of ipa antib ... | 1992 | 1607690 |
| virulence phenotypes of shigella flexneri 2a avirulent mutant 24570 can be complemented by the plasmid-coded positive regulator virf gene. | avirulent mutation of an opaque colony variant of shigella flexneri 2a designated 24570 has been believed to be linked with the glpk locus of the chromosome. however, avirulent phenotypes of the 24570 strain could be complemented by the invasion plasmid-coded virf gene, a positive regulator for invasion genes. the 24570 strain had a dna structural alteration upstream of the virf gene. | 1992 | 1624118 |
| antibodies to shiga holotoxin and to two synthetic peptides of the b subunit in sera of patients with shigella dysenteriae 1 dysentery. | acute- and convalescent-phase sera from 18 thai patients and convalescent-phase sera from two israeli patients and one bangladeshi patient with shigella dysenteriae 1 (shiga) dysentery were tested by enzyme-linked immunosorbent assay to detect antibodies that bind s. dysenteriae lipopolysaccharide (lps), shiga holotoxin, or two synthetic peptides representing epitopes from the b subunit of shiga toxin. paired sera from 24 maryland adults with shigella flexneri 2a or shigella sonnei diarrhea serv ... | 1992 | 1629317 |
| mxia of shigella flexneri 2a, which facilitates export of invasion plasmid antigens, encodes a homolog of the low-calcium-response protein, lcrd, of yersinia pestis. | the plasmid-encoded invasion plasmid antigen (ipa) export accessory locus of shigella flexneri 2a, mxia, was cloned, and the complete dna sequence of the gene was determined. the mixa open reading frame was found to encode a polypeptide of 74.03 kda with a pi of 5.02. a hydropathy analysis of the predicted protein revealed a hydrophilic c terminus and an extremely hydrophobic n terminus without a cleavable signal sequence but with several potential membrane-spanning regions. while a homology sea ... | 1992 | 1639496 |
| construction of a physical map of the chromosome of shigella flexneri 2a and the direct assignment of nine virulence-associated loci identified by tn5 insertions. | to establish the molecular basis of the chromosomal virulence genes of shigella flexneri 2a (ysh6000), a notl restriction map of the chromosome was constructed by exploiting notl-linking clones, partial notl digestion and dna probes from various genes of escherichia coli k-12. the map revealed at least three local differences in the placements of genes between ysh6000 and e. coli k-12. using the additional notl sites introduced by tn5 insertion, nine virulence loci identified previously by rando ... | 1991 | 1662762 |
| an o antigen can interfere with the function of the yersinia pseudotuberculosis invasin protein. | escherichia coli strains harbouring the yersinia pseudotuberculosis inv gene are able to enter cultured mammalial cells. we show here that this property is not shared by all enteric bacteria, since shigella flexneri 2a cured of its virulence-associated plasmid and harbouring the inv gene is unable to enter mammalian cells efficiently. mapping studies showed that the region of the chromosome responsible for this phenotype includes rfab, a locus involved in the production of o antigen. s. flexneri ... | 1991 | 1710312 |
| sensitivity of shigella flexneri and escherichia coli bacteria to bacteriophages and to colicins, lost or established by the acquisition of r plasmids. | lac+ recombinant of shigella flexneri 2a carrying r-factors of the standard set have been constructed. the r+ transconjugants obtained have been compared with the original strain with respect to their susceptibility to a set of bacteriophages recommended for phagetyping of shigella strains and to a set of colicins. it have been found that as a result of acquiring some r-factors the susceptibility to bacteriophages changes; presence of certain r-factors causes susceptibility, that of other r-fact ... | 1990 | 1715637 |
| technological aspect of the production of live dysentery vaccines for oral administration. | an experimental technology for the production of live freeze-dried vaccines prepared from attenuated shigella flexneri 2a and shigella sonnei i strains was developed. it is based on the cultivation of bacterial strains in a fermentor under conditions which ensure high yields. the strains grow in s-form, their antigenic structure is preserved and they remain non-virulent. the attenuating markers are stable. the freeze-dried vaccines retain good immunogenicity when applied intra-intestinally to ra ... | 1991 | 1805499 |
| effect of prior infection with virulent shigella flexneri 2a on the resistance of monkeys to subsequent infection with shigella sonnei. | all virulent shigellae have large plasmids. plasmid-associated genes encode the expression of membrane-associated proteins (map), some of which correlate with the ability to invade susceptible epithelial cells. these map are serologically related in all of the shigella serotypes and evoke an antibody response after infection. to determine whether the map have a significant role in protection, 24 monkeys were infected with virulent shigella flexneri 2a. after recovery, one group (with controls) w ... | 1991 | 1869840 |
| virulence phenotype and genetic characteristics of the t32-istrati shigella flexneri 2a vaccine strain. | the t32-istrati strain, which has been used as an oral attenuated shigella flexneri 2a vaccine, has lost the invasive phenotype due to a spontaneous deletion in the shigella virulence plasmid. this deletion has eliminated three plasmid loci (ipabcda, inva and virg) that are necessary for production of a positive sereny test by shigella species. virulence in the sereny test was reconstituted in the t32-istrati strain by the conjugal transfer of an intact 140 m da virulence plasmid from s. flexner ... | 1991 | 1872021 |
| [an immunomorphological study of the lymphoid organs in the experimental administration of virulent and avirulent shigella flexneri 2a strains]. | | 1991 | 1887717 |
| epidemiologic patterns of acute diarrhea and endemic shigella infections in children in a poor periurban setting in santiago, chile. | to prepare a field site for evaluating preventive interventions against endemic shigellosis, the authors followed prospectively a cohort of 360 children (90 each of children aged 0-11, 12-23, 24-35, and 36-47 months) in santa julia, a low socioeconomic area in santiago, chile, from november 1986 through april 1989 with twice weekly household visits for diarrheal disease; infants replaced children who reached 60 months of age. coprocultures on 2 consecutive days from children with diarrhea and fr ... | 1991 | 1951266 |
| differences in blood group b-specific mucinase activity between virulent and avirulent shigella flexneri 2a strains. | based on our previous findings we postulate that the production of blood group b-degrading mucinase by shigella flexneri 2a is related to virulence. the virulent s. flexneri 2a strain m4243 produced a blood group b mucinase which decreased the blood group b reactivity of germ-free mouse mucins by a factor of 16 and the b reactivity of human saliva by a factor of 32. avirulent s. flexneri 2a b-1, serologically similar, but not genetically identical to the m4243 strain, failed to degrade the blood ... | 1991 | 1961109 |
| construction of aromatic dependent shigella flexneri 2a live vaccine candidate strains: deletion mutations in the aroa and the arod genes. | live shigella flexneri 2a vaccine candidate strains with deletion mutations in the aro genes were constructed. tn10-generated auxotrophic mutations were transduced from escherichia coli to s. flexneri 2a with bacteriophage p1cmcts. the tetracycline-sensitive derivatives of tn10 mutants obtained were selected on bochner's medium and checked by dna-dna hybridization using aroa and arod gene specific probes. the vaccine candidate strains were tested to assess the efficacy of protection in guinea-pi ... | 1991 | 2008803 |
| two novel virulence loci, mxia and mxib, in shigella flexneri 2a facilitate excretion of invasion plasmid antigens. | a bank of over 4,200 lacz protein fusions in shigella flexneri 2a was screened for fusions to temperature-regulated promoters. one mutant, bs260, was completely noninvasive on hela cells and mapped to a region on the 220-kb virulence plasmid in which we had previously localized several avirulent temperature-regulated operon fusions (a.e. hromockyj and a.t. maurelli, infect. immun. 57:2963-2970, 1989). the phenotype of bs260 was similar to that of the previously identified mxi (membrane expressio ... | 1991 | 2037361 |
| potential shigella flexneri 2a and shigella sonnei i live vaccinal strains. characterization of immunogenicity in animal models. | rats and rabbits were immunized intraintestinally with different doses of virulent and nonvirulent live shigella flexneri 2a and shigella sonnei i strains. the nonvirulent strains had one or two attenuating markers. the period of excretion with the faeces of the bacteria and of their polysaccharide antigens, the proliferation of antigen-binding and antibody-producing cells in the spleens and gut-associated lymphoid tissues and the levels of antibodies in sera and faeces were studied. attenuated ... | 1990 | 2099082 |
| live shigella flexneri 2a and shigella sonnei i vaccine candidate strains with two attenuating markers. i. construction of vaccine candidate strains with retained invasiveness but reduced intracellular multiplication. | live shigella flexneri 2a and shigella sonnei phase i vaccine candidate strains with two virulence-reducing markers were constructed through stepwise incorporation of weakly attenuating purine auxotrophy with subsequent rifampicin-resistance (rna polymerase) mutation to yield optimal attenuation. these vaccine candidate strains showed an unaltered plasmid profile; did not cause keratoconjunctivitis in the sereny test, while being excreted for a short but still marked period and providing partial ... | 1990 | 2180230 |
| live shigella flexneri 2a and shigella sonnei i vaccine candidate strains with two attenuating markers. ii. preliminary results of vaccination of adult volunteers and children aged 2-17 years. | shigella flexneri 2a and shigella sonnei i vaccine candidate strains were tested for tolerance in 14 adults as well as for tolerance and immunogenicity in children aged 2-17 years. for fresh culture material, the limit for side effects fading within 36 h such as meteorism, loose stools, tenesmus and slight temperature, and tolerated by volunteers was 3 x 10(9) colony-forming units (c.f.u.). excretion of vaccine strain germs for 2-3 days was observed only at doses of 10(10) c.f.u. and greater (2- ... | 1990 | 2180231 |
| molecular epidemiology of shigella infection in central australia. | shigellosis is endemic in central australia and the infections are predominantly due to shigella flexneri 6, shigella flexneri 2a and shigella sonnei. plasmid profiles of isolates collected from 1985-9, suggested that infections caused by shigella flexneri 6 were predominantly due to a single clone, whereas those caused by shigella flexneri 2a and shigella sonnei were due to several genetically diverse strains, although strains with identical plasmid profiles were found in widely separated geogr ... | 1990 | 2200701 |
| [cloning of shigella flexneri 2a genes coding for restriction- modification system sfl2ai]. | the sfl2ai system of restriction-modification (rm) was revealed in the cells of shigella flexneri encoded by pkmr114 plasmid belonging to the incn incompatibility group. the genes for sfl2ai rm system were cloned. the system was ascribed to the enzymes of the ecorii specificity, as shown by in vivo and in vitro experiments. restriction analysis of these genes' region and antigenic properties of the sfl2ai endonuclease pointed to significant differences between this and ecorii rm systems. | 1990 | 2227395 |
| [membrane activity of a cell-free filtrate of shigella flexneri 2a]. | in the course of metabolism in shigella flexneri 2a strain there was noted secretion of a membrane-tropic factor into media. this factor increased the conductivity of bilayer lipid membranes causing formation of ionic channels in them. minimal conductivity of the channels was about 25 ps in 0.5 m nacl; at ph 7-8 the channels exhibited cation-anion selectivity. the calculated number of cation transfer (t+) was elevated with an increase in the channel amplitude, approaching 0.86. since the conduct ... | 1985 | 2413620 |
| hla-b27m1m2 and high immune responsiveness to shigella flexneri in post-dysenteric arthritis. | the heterogeneous hla-b27 antigen is closely associated with post-infectious or reactive arthritis (rea) and is comprised of two serologically defined variants: b27m1+m2+ and b27m1+m2-. an outbreak of dysentery (n = 120) caused by a shigella flexneri 2a strain, which possessed cell envelope antigens with epitopes resembling b27m2, resulted in five b27m1+m2+ patients with rea. the remaining seven b27m1+m2+, one b27m1+m2- and all but three b27-negative patients remained free of joint symptoms; the ... | 1986 | 2428743 |
| functional organization and nucleotide sequence of virulence region-2 on the large virulence plasmid in shigella flexneri 2a. | the 7 kb virulence region-2 of the large (virulence) plasmid in shigella flexneri 2a encodes several proteins required for invasion of intestinal epithelial cells. insertion and deletion mutagenesis, dna subcloning and sds-polyacrylamide gel electrophoresis of proteins synthesized in minicells demonstrated five genes in this region. they encode 24, 18, 62 (ipab), 41 (ipac) and 37 (ipad)-kilodalton (kd) proteins. complementation of tn5-induced mutations in region-2 with the above plasmid construc ... | 1989 | 2552264 |
| virg, a plasmid-coded virulence gene of shigella flexneri: identification of the virg protein and determination of the complete coding sequence. | on the 230-kilobase-pair (kb) virulence plasmid of shigella flexneri 2a strain ysh6000, at least seven separate genetic determinants have been identified. one of them, an approximately 4-kb region, virg, that is required for the sereny reaction, was extensively studied to examine the role of the virg region. the phenotype of a virg- mutant (m94) of ysh6000 in the cytoplasm of cultured mk cells was characterized by a kinetic study of the invading shigellae. the observed phenotype of m94 in the cy ... | 1989 | 2644195 |
| identification of an escherichia coli gene homologous to virr, a regulator of shigella virulence. | virulence in shigella spp., as well as in strains of enteroinvasive escherichia coli, is regulated by growth temperature. previously, virr had been identified as the gene controlling the temperature-regulated expression of shigella virulence. since shigella spp. and e. coli are also known to share greater than 90% dna sequence homology, we sought to determine if nonpathogenic e. coli k-12 c600 contains a gene homologous to the shigella flexneri 2a gene virr. through the use of transduction and m ... | 1989 | 2651420 |
| congo red-mediated regulation of levels of shigella flexneri 2a membrane proteins. | the ability of shigella spp. to bind congo red from agar medium is generally correlated with their virulence properties. we used a metabolically active culture of shigella flexneri 2a to determine the effect of congo red on its membrane protein profiles. virulent s. flexneri grown in the presence of congo red at 37 degrees c showed increased levels of three proteins with mrs of 43,000, 58,000, and 63,000 (43k, 58k, and 63k proteins) in the sarkosyl-soluble membrane fractions. the observed phenom ... | 1989 | 2663721 |
| [the role of delayed hypersensitivity in the development of an experimental dysentery infection and vaccinal process]. | the results of experiments, indicating the development of cell-mediated delayed hypersensitivity (dh) skin reaction, its dependence on the virulence of shigella flexneri 2a, the dose and the character of the antigen used for testing the reaction, are presented. one of the immunologically active components of s. flexneri virulent strain 2a no. 516 is a biologically active thermolabile factor detected in filtrate and supernatant fluid. these data suggest that the immunosuppressive action of the vi ... | 1989 | 2698032 |
| virulence-associated genetic regions comprising 31 kilobases of the 230-kilobase plasmid in shigella flexneri 2a. | by random transposon tn5 insertions, we previously identified six virulence-associated sali fragments, b, d, f, g, h, and p, in the 230-kilobase plasmid pmysh6000 of shigella flexneri 2a. in this study, we analyzed the sites of 134 independent tn5 insertions on four contiguous sali fragments, b, p, h, and d, of pmysh6000 and identified five virulence-associated regions; four were associated with inducing a positive sereny test (ser), invasion into epithelial cells (inv), binding to congo red (pc ... | 1988 | 2836357 |
| molecular alteration of the 140-megadalton plasmid associated with loss of virulence and congo red binding activity in shigella flexneri. | a plasmid of about 140 megadaltons has been associated with the invasiveness of shigella flexneri. upon subculturing in liquid media of fully virulent isolates of shigella flexneri 2a ysh6000, which contains only a 230-kilobase-pair (kbp) plasmid in addition to 3.3- and 4.2-kbp cryptic plasmids characteristic to all s. flexneri strains, loss of invasiveness, loss of congo red binding activity (pcr), and complete loss of, or a deletion, or even a single-site is insertion in the plasmid occurred s ... | 1986 | 3002985 |
| isolation, characterization, and mapping of tn5 insertions into the 140-megadalton invasion plasmid defective in the mouse sereny test in shigella flexneri 2a. | using shigella flexneri 2a ysh6000, we isolated 304 independent tn5 insertion mutants in the 230-kilobase invasion plasmid, pmysh6000. the site of each tn5 insertion was assigned to 23 sali fragments on the previously made sali cleavage map of pmysh6000. among the 304 insertions, 150 were negative in expression of four phenotypes examined (mouse sereny test [ser], invasion into epithelial cells [inv], congo red binding [pcr], and inhibition of bacterial growth [igr] ): 12 were ser- inv+ pcr+ igr ... | 1986 | 3019891 |
| dna sequence and product analysis of the virf locus responsible for congo red binding and cell invasion in shigella flexneri 2a. | the dna sequence of virf, a locus associated with virulence and the ability to bind congo red in shigella flexneri 2a that is located on a 140-megadalton (230-kilobase) plasmid, was determined and analyzed. it was rich in a and t. the direction of transcription of virf was determined by using a chloramphenicol resistance cartridge. an open reading frame readable in this direction was found. three proteins, 30, 27, and 21 kilodaltons, all corresponding to those predicted from the above sequence, ... | 1986 | 3021627 |
| genetic relatedness of the basic replicon of the virulence plasmid in shigellae and enteroinvasive escherichia coli. | the regions required for replication (rep) and for stable maintenance (stb) of the 230 kilobase virulence plasmid, pmysh6000, in shigella flexneri 2a ysh6000 were identified on the restriction enzyme sa/l fragments, c and o, respectively. the stable plasmid, pmysh6610, consisting of adjacent fragments c and o was found to belong to the incompatibility group fl. in all strains of shigellae and enteroinvasive escherichia coli (eiec) tested, virulence plasmids were found to be highly homologous wit ... | 1988 | 3070262 |
| [reaction of the hematopoietic system in mice to the administration of virulent and avirulent strains of shigella flexneri 2a]. | the influence of live bacteria and antigenic preparations of virulent and avirulent stains of shigella flexneri 2a on the endogenous splenic colony formation in murine hematopoietic cells has been studied. the different stimulating activity of live microbial cells of virulent and avirulent strains shigella flexneri 2a and their antigenic preparations on the endogenous colony formation has been shown. the effect observed depends on the preparation doses and time of their administration before irr ... | 1987 | 3304434 |
| introduction of shigella flexneri 2a type and group antigen genes into oral typhoid vaccine strain salmonella typhi ty21a. | for protection against dysentery caused by shigella flexneri 2a, an in vivo-constructed recombinant plasmid with genes specifying the s. flexneri type and group antigens located near the pro (min 6) and his (min 44) chromosomal markers, respectively, was made and transferred to the gale salmonella typhi strain ty21a. strain ty21a carrying this recombinant plasmid was shown by immunological and biochemical analyses to express the s. flexneri 2a type and group antigens. mice immunized with this va ... | 1987 | 3312013 |
| technological investigations with attenuated strains of shigella for production of live vaccines. 1. cultivation in a fermenter of an attenuated strain s. flexneri 2a with two markers. | a method was developed for cultivation of the strain shigella flexneri 2a 77 with two attenuated markers. it ensures the preservation of the initial properties of the strain. the regimen for control of dissolved oxygen level was optimized. it was established that yeast extract is a necessary component of the nutritive medium used. the role of the phase and quantity of the inoculum for growth of the bacterial population has been clarified. fresh fermenter culture, applied in rats, shows a high im ... | 1987 | 3314220 |
| effects of bacterial lipopolysaccharide on the binding of lymphocytes to endothelial cell monolayers. | preincubation of human umbilical vein endothelial cell (ec) monolayers with 1 ng to 10 micrograms/ml lipopolysaccharide (lps) increased the binding of t lymphocytes to ec. the effect was maximal at lps concentrations of 0.1 to 10 micrograms/ml, and occurred with lps derived from escherichia coli (serotypes 0111:b4 and 0127:b8), shigella flexneri (serotype 2a), serratia marcescens (serotype 0:3), and yersinia entercolitica (serotype 0:3). the increased binding appeared to be mediated primarily th ... | 1986 | 3484495 |
| molecular cloning of a genetic determinant for congo red binding ability which is essential for the virulence of shigella flexneri. | a dna sequence of about 1.0 kilobase (kb) derived from a 230-kb (140-megadalton) plasmid in a fully virulent shigella flexneri 2a strain, ysh6000, was cloned into escherichia coli k-12 by selecting for the ability to bind congo red (pcr+ phenotype). it was mapped and localized within the sali restriction fragment f on the plasmid. this clone converted an s. flexneri strain which is avirulent as a result of a small deletion in the plasmid to full virulence but did not convert those without the 23 ... | 1986 | 3510977 |
| characterization of transferable plasmids from shigella flexneri 2a that confer resistance to trimethoprim, streptomycin, and sulfonamides. | a set of plasmids conferring resistance to several antibiotics, including the combination of trimethoprim and sulfamethoxazole, has been isolated from escherichia coli following conjugative cotransfer from a clinical isolate of shigella flexneri 2a. one of the plasmids, pcn1, was shown by subcloning and dna sequencing to carry a gene encoding a trimethoprim-insensitive dihydrofolate reductase identical to that found in e. coli transposon 7. this plasmid was also shown to confer resistance to bot ... | 1986 | 3517903 |
| epidemic reiter's syndrome following an outbreak of shigellosis. | we prospectively studied the occurrence of reiter's syndrome (rs) or reactive arthritis (rea) in 205 of 349 cruise-ship passengers who attended a buffet ashore and developed shigella flexneri 2a enteritis. five passengers probably had rs/rea and 16 were possible or doubtful cases of rs/rea. hla-b27 was identified in 4 of 5 probable rs cases, but was not present in any of the 16 possible or doubtful cases nor in any of 20 passengers (controls) without any symptoms of rs/rea. there was no statisti ... | 1986 | 3533609 |
| lack of serologically defined arthritogenic shigella flexneri cell envelope antigens in post-dysenteric arthritis. | post-dysenteric or reactive arthritis (rea) is closely associated with hla-b27. this histocompatibility antigen is heterogeneous and consists of 2 serologically defined variants: b27m1+m2+ and b27m1+m2-. this paper gives a qualitative evaluation of the antibodies present in the sera of 62 patients with dysentery due to shigella flexneri 2a, a known arthritogenic bacterium. the patients were classified in 4 groups: b27m1+m2+rea+ (n = 5), b27m1+m2+rea- (n = 7); b27m1+m2-rea- (n = 1); b27-rea- (n = ... | 1986 | 3533766 |
| [interrelation of erythropoiesis and lymphopoiesis in experimental infectious processes and in viral leukemogenesis]. | interrelation of erythropoiesis and immune response was studied in mice of various lines infected with mycoplasma species, shigella flexneri 2a and rauscher leukemia virus (r-mlv). intensity of erythropoiesis was estimated by the endocolonization data of sublethally irradiated mice and 59fe incorporation, while immune reactivity--by generation of splenic antibody-forming cells in response to immunization with sheep erythrocytes. the inverse correlation between the ability of infectious agents to ... | 1985 | 3899611 |
| [live shigella flexneri 2a and shigella sonnei vaccines (author's transl)]. | | 1974 | 4216253 |
| mutation in shigella flexneri resulting in loss of ability to penetrate hela cells and loss of glycerol kinase activity. | a colonial variant of a virulent shigella flexneri 2a has lost both virulence and glycerol kinase activity. it also has several other altered characteristics: lowered ability to oxidize tricarboxylic acid cycle intermediates, increased electrophoretic mobility, and decreased sensitivity to sodium lauryl sulfate. genetic analysis has revealed that the gene governing glycerol kinase activity in shigella has a different chromosomal locus than that from escherichia coli. furthermore, transduction of ... | 1974 | 4363235 |
| [analysis of lipopolysaccharide in shigella flexneri 2a strains , pathogenic or nonpathogenic for keratoconjunctivitis in guinea pigs]. | | 1972 | 4551587 |
| behavior of coliphage lambda in shigella flexneri 2a. | the insensitivity of wild-type shigella flexneri 2a to coliphage lambda is a consequence of its native genetic defect in the mala gene cluster. the "smooth" s. flexneri 2a lipopolysaccharide layer affects the efficient adsorption of lambda. derivatives, capable of serving as functional hosts for lambda, were obtained by repairing the mala lesion, enabling the expression of the malb-lambdarcp region of s. flexneri. introduction of a mutation into s. flexneri causing a "rough" lipopolysaccharide c ... | 1972 | 4563593 |
| virulence of shigella flexneri hybrids expressing escherichia coli somatic antigens. | the genes controlling either escherichia coli somatic antigen 8 or 25 were conjugally transferred to virulent shigella flexneri 2a recipients to determine whether the aquisition of these antigens would affect the virulence of the resulting hybrid. a high proportion of such hybrids were found to be rough and hence were avirulent. some smooth s. flexneri hybrids which replaced their native group antigens with e. coli factor 25 were still virulent in the animal models employed. all s. flexneri o-8 ... | 1972 | 4569915 |
| freeze-drying of live oral streptomycin-dependent mutant shigella vaccines: survival of streptomycin-dependent shigella flexneri 2a after freeze-drying. | | 1972 | 4572041 |
| [correlation of biochemical features and pathogenicity of shigella. 3. comparison of free amino acid pools in shigella flexneri 2a strains producing and not producing keratoconjunctivitis in guinea pigs]. | | 1973 | 4575294 |
| factors affecting virulence of shigella flexneri: avirulent strain with altered metablism of succinate, fumarate, and malate. | it has been found that a mutation of shigella flexneri 2a to avirulence can result in altered metabolism of tricarboxylic acid cycle acids, but the effect is strongly dependent on growth conditions. mutant cells harvested from stationary-phase cultures grown with vigorous shaking in nutrient broth oxidize succinate, fumarate, and malate much more slowly than do wild-type cells. cell-free extracts from such cells show similar differences in oxidative ability. these differences were less pronounce ... | 1973 | 4586861 |
| [protective role of type-specific shigella flexneri 2a antigen in interaction with immune sera in passive protection experiments on a "lung" model]. | | 1973 | 4594836 |
| effect of calcium on the cell infectivity of virulent shigella flexneri 2a. | | 1974 | 4610242 |
| serologic analysis of lac+ recombinants of e. coli hfrc and shigella flexneri 2a. | | 1972 | 4621298 |
| mutation in shigella flexneri 2a resulting in increased electrophoretic mobility. | an avirulent mutant of shigella flexneri 2a, when grown in broth containing calcium ions, was found to have a three- to fourfold increase in electrophoretic mobility toward the anode when compared to its virulent parent. under these same growth conditions, it was found that the avirulent strain was made more electronegative in the presence of ethylenediaminetetraacetic acid (edta). edta had no effect on the electrophoretic mobility of the virulent strain. in the absence of added calcium in the g ... | 1972 | 4629253 |
| investigations on the sensitivity of isolated strains of shigella flexneri 2a from mass outbreaks of dysentery to colicins of the shigella sonnei. | | 1969 | 4899703 |
| [possibility of using type-specific bacteriophages for the lysotyping of shigella flexneri 2a and 3a and also of other types of shigella. (preliminary note)]. | | 1968 | 4912628 |
| [conjugation of e. coli p4x and shigella flexneri 2a. ii. production of s. flexneri hfr strain]. | | 1970 | 4913813 |
| keratoconjunctivitis test in shigella flexneri 2a hybrids obtained in a cross with different strains of e. coli k12. | | 1970 | 4913850 |
| [relation between virulence and colony type in shigella flexneri 2a hybrids with defined genetic characteristics]. | | 1971 | 4932285 |
| [evaluation of the significance of type-specific antigen for the virulence of shigella flexneri 2a in studying recombinants of definite genetic classes]. | | 1971 | 4941815 |
| salicin-fermenting variant of shigella flexneri serotype 2a. | | 1965 | 4952941 |
| fluorescent-antibody and histological study of vaccinated and control monkeys challenged with shigella flexneri. | formal, samuel b., (walter reed army institute of research, washington, d.c.), t. h. kent, s. austin, and e. h. labrec. fluorescent-antibody and histological study of vaccinated and control monkeys challenged with shigella flexneri. j. bacteriol. 91:2368-2376. 1966.-groups of monkeys were fed four doses of a living escherichia coli-shigella flexneri 2a hybrid strain, and, together with control animals, were challenged with virulent s. flexneri 2a. two experiments were carried out; in the first, ... | 1966 | 4957617 |
| experimental infection with small doses of virulent shigella flexneri 2a in cynomolgus monkeys (macaca irus). clinical and bacteriological observations. | | 1967 | 4964232 |
| shigellosis in cynomolgus monkeys (macaca irus). v. resistance acquired by the repetition of experimental oral infection with shigella flexneri 2a and fluctuation of serum agglutinin titer. | | 1967 | 4966140 |
| oral challenge with shigella flexneri 2a in cynomolgus monkeys having extremely high titer of serum agglutinin. | | 1968 | 4974278 |
| shigellosis in cynomolgus monkeys (macaca irua). vi. the inoculation with various doses of shigella flexneri 2a into cecal lumen. | | 1968 | 4974847 |
| [isolation of a sorbitol fermenting variant of shigella flexneri 2a in osaka]. | | 1969 | 4979595 |
| shigellosis in cynomolgus monkeys (macaca irus). vii. experimental production of dysentery with a relatively small dose of shigella flexneri 2a in ascorbic acid deficient monkeys. | | 1969 | 4981384 |
| dysentery produced by oral administration of the colonic contents of cynomolgus monkeys infected with shigella flexneri 2a. | | 1970 | 4992614 |
| studies on vaccination against bacillary dysentery. 5. studies in erythrocebus patas. | in earlier studies in man it has been demonstrated that streptomycin-dependent shigellae, if given orally in 5 sufficiently large doses, confer a very high type-specific protection against bacillary dysentery.in the present study, 2 groups of erythrocebus patas monkeys were immunized with live streptomycin-dependent shigella flexneri 2a, and a third group was not vaccinated. one of the vaccinated groups was given streptomycin with each dose of the live vaccine. the animals that received streptom ... | 1970 | 4993182 |
| bacillary dysentery in cynomolgus monkeys following the administration with shigella flexneri 2a by the anal route. | | 1971 | 5003951 |
| studies on vaccination against bacillary dysentery. 3. effective oral immunization against shigella flexneri 2a in a field trial. | in may 1963 a live vaccine prepared from streptomycin-dependent shigella flexneri 2a was administered to 355 soldiers stationed in an area of yugoslavia in which bacillary dysentery was hyperendemic. five oral doses were given every third day. 382 unvaccinated soldiers from the same unit served as controls. both groups were closely followed up until 16 september.examination of 1637 rectal swabs from the vaccinated and control groups indicated that vaccination did not affect the carrier rate. the ... | 1965 | 5294180 |
| [antidysentery vaccination. xi. a. pathogenic action on the guinea pig intestine following the administration "per os" of shigella flexneri 2a strains (pathogenic and non-pathogenic for guinea pig conjunctiva). b. attempted immunization by oral route as compared to the intraperitoneal route]. | | 1964 | 5318791 |
| chemotherapy of mice experimentally infected with shigella flexneri. | a chronic infection with shigella flexneri 2a has been established in mice for the evaluation of compounds for therapeutic potential. evidence of infection is indicated by prolonged symptomless excretion in the feces and by positive isolation of organisms from different segments of the intestinal tract and from mesenteric lymph nodes. serum antibody titer reaches a maximum after 9 days of infection and remains at a low level until 32 days postinfection. in this model, five drugs used in human sh ... | 1970 | 5422307 |
| the response of man to virulent shigella flexneri 2a. | | 1969 | 5780532 |
| [research on active immunity of man in bacillary dysentery. 3. maintenance of the non-pathogenic character of the shigella flexneri 2a txxxii strain orally administered to volunteers]. | | 1965 | 5877879 |
| [antidysenteric vaccination. xiv. immunizing action on the guinea pig conjunctiva of various toxic extracts of pathogenic shigella flexneri 2a ti, as compared with that of live cultures of two non-pathogenic strains of shigella flexneri 2a]. | | 1966 | 5973711 |