Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| new mannitol negative variety of shigella flexneri 2a. | 1956 | 13421654 | |
| microscopic characteristics of colonies of shigella flexneri 2a and 2b and their relation to antigenic composition, mouse virulence and immunogenicity. | 1957 | 13429082 | |
| experimental shigella infections. v. studies in germ-free guinea pigs. | formal, samuel b., (walter reed army institute of research, washington, d. c.), gustave dammin, helmuth sprinz, donald kundel, herman schneider, richard e. horowitz, and martin forbes. experimental shigella infections. v. studies in germ-free guinea pigs. j. bacteriol. 82:284-287. 1961.-germ-free guinea pigs succumb after oral infection with shigella flexneri serotype 2a; they survive a similar challenge with either a strain of escherichia coli or a culture of lactobacillus. animals monocontamin ... | 1961 | 13700794 |
| [phage typing of shigella. iii. stability of the bacteriophage types in shigella flexneri 2a]. | 1962 | 13956957 | |
| virulence of escherichia-shigella genetic hybrids for the guinea pig. | falkow, stanley (walter reed army institute of research, washington, d.c.), h. schneider, l. s. baron, and s. b. formal. virulence of escherichia-shigella hybrids for the guinea pig. j. bacteriol. 86:1251-1258. 1963.-genetic recombination studies between donor escherichia coli and recipient shigella flexneri 2a strains were employed to examine alterations in the virulence of shigella hybrids for guinea pigs. the genetic studies indicated that several chromosomal regions of e. coli and s. flexner ... | 1963 | 14086097 |
| [mannitol-negative variation of shigella flexneri 2a]. | 1963 | 13944418 | |
| shigellosis in cynomolgus monkeys (macaca irus). ii. experimental infection with shigella flexneri 2a with special references to clinical and bacteriological findings. | 1964 | 14279864 | |
| [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 | |
| epithelial cell penetration as an essential step in the pathogenesis of bacillary dysentery. | labrec, eugene h., herman schneider, thomas j. magnani, and samuel b. formal. epithelial cell penetration as an essential step in the pathogenesis of bacillary dysentery. j. bacteriol. 88:1503-1518. 1964.-a parent strain of shigella flexneri 2a and a colonial mutant derived from it were studied in three animal models. both strains were equally virulent for mice when living cells suspended in hog gastric mucin were injected by the intraperitoneal route. feeding the parent strain to starved guinea ... | 1964 | 16562000 |
| salicin-fermenting variant of shigella flexneri serotype 2a. | 1965 | 4952941 | |
| [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 | |
| salicin-fermenting variant of shigella flexneri serotype 2a. | 1965 | 14345179 | |
| 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 |
| protection of monkeys against experimental shigellosis with attenuated vaccines. | formal, samuel b. (walter reed army institute of research, washington, d.c.), e. h. labrec, amos palmer, and stanley falkow. protection of monkeys against experimental shigellosis with attenuated vaccines. j. bacteriol. 90:63-68. 1965.-two shigella flexneri 2a strains of reduced virulence were used as oral vaccines to protect monkeys against experimental challenge. one strain, a spontaneous mutant, had lost its ability to cause disease and was unable to penetrate the intestinal epithelium and re ... | 1965 | 16562044 |
| [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 | |
| 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 | |
| [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 | |
| investigations on the sensitivity of isolated strains of shigella flexneri 2a from mass outbreaks of dysentery to colicins of the shigella sonnei. | 1969 | 4899703 | |
| [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 | |
| the response of man to virulent shigella flexneri 2a. | 1969 | 5780532 | |
| 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 |
| 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 |
| [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 | |
| infection of cultured mouse macrophages with shigella flexneri. | virulent, avirulent, and attenuated hybrid strains of shigella flexneri 2a are equally susceptible to phagocytosis by cultured mouse peritoneal macrophages. the virulent strain is highly lethal for the macrophages, whereas the avirulent is not and is killed. the attenuated hybrid strain is intermediate in its lethality. comparable results were obtained by using virulent and avirulent s. flexneri 1b, 3, and 5. destruction of macrophages occurs shortly after infection, suggesting virulent strains ... | 1970 | 16557758 |
| [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 | |
| bacillary dysentery in cynomolgus monkeys following the administration with shigella flexneri 2a by the anal route. | 1971 | 5003951 | |
| identification of two widely separated loci conferring nicotinic acid dependence on wild-type shigella flexneri 2a. | two widely separated loci causing the nicotinic acid dependence of wild-type shigella flexneri 2a were identified by intergeneric mating procedures and found to be closely linked to the gal and fuc chromosomal determinants. | 1971 | 16558004 |
| [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 | |
| 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 |
| [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 | |
| [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 |
| 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 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 | |
| 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 | |
| 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 |
| 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 |
| [local immune response in rabbits following enteral immunization with live attenuated bacterial enterobacteriaceae vaccines]. | streptomycin-dependent and inactivated shigella flexneri 2a and shigella sonnei strains were intra-intestinally applied to rabbits for immunisation. rosette and plaque tests and well as indirect haemagglutination gave short-time secretion of low titres of specific copro-antibody, following monovaccines and bivaccines. high titres of secretory antibody were induced, depending on doses, by re-immunisation. no antigen competition was established. the localised immune response caused by shigella liv ... | 1980 | 6998404 |
| isolation and characterization of minicell-producing mutants of shigella spp. | minicells are small, anucleate cells resulting from aberrant cell divisions at the polar ends of bacilli. we have isolated minicell-producing mutant strains of shigella flexneri 2a (mc-i) and shigella dysenteriae 1 (mc-v) after mutagenesis with n-methyl-n'-nitro-n-nitrosoguanidine. microscopically, broth cultures of mc-i and mc-v were found to contain free minicells, normal cells, and filamentous cells with polar, attached minicells. both strains retained their ability to provoke keratoconjuncti ... | 1980 | 7002790 |
| protein synthesis in hela or henle 407 cells infected with shigella dysenteriae 1, shigella flexneri 2a, or salmonella typhimurium w118. | the incorporation of [14c]leucine into protein was studied in two mammalian cell lines which had been infected with strains of shigella dysenteriae 1, shigella flexneri 2a, or salmonella typhimurium w118. these cell lines differed in susceptibility to the effects of exogenously applied shiga cytotoxin. all invasive shigella strains (which synthesize this toxin to a greater or lesser degree) were found to inhibit protein synthesis in both cell lines with equal efficiency. leucine accumulation con ... | 1981 | 7012026 |
| shigella and shigellaemia. | two cases of bacteraemia with shigella flexneri 2a in children are described. they illustrate the wide variety of clinical manifestations of shigellosis, ranging from benign gastroenteritis to septicaemia associated with severe extra-intestinal manifestations. | 1981 | 7017908 |
| [obtaining shigella flexneri 2a mutants defective in utilization of certain carbon sources, their genetic and biological characteristics]. | various methods, including selection by resistance to the antibiotic mecillinam have been used to obtain sh. flexneri mutants capable of utilizing mannitol and mannose as the sources of carbon. the mutation which determines this phenotype is localized in str-spc area and cotransduced with str a gene (28-33%). the appearance of this mutation in the initial sh. flexneri strain 516 led to a decrease in the virulence of this strain for guinea-pigs. the restoration of its properties and the partial r ... | 1981 | 7018130 |
| early colonic lesions in experimental shigella infection in rhesus monkeys: revisited. | rhesus monkeys (macaca mulatta), given 3 x 10(8) to 5 x 10(10) shigella flexneri 2a orally, developed signs of acute shigellosis within 24 hours. a diffuse acute colitis was well established at 48 hours. the inflammatory reaction was confined to the mucosa. the submucosa showed only edema. the shigellae were found predominantly in the columnar cells of the surface epithelium, less frequently in those of the crypt, and least frequently in the lamina propria. shigella bacilli invaded the columnar ... | 1982 | 6153000 |
| early colonic lesions in experimental shigella infection in rhesus monkeys: revisited. | rhesus monkeys (macaca mulatta), given 3 x 10(8) to 5 x 10(10) shigella flexneri 2a orally, developed signs of acute shigellosis within 24 hours. a diffuse acute colitis was well established at 48 hours. the inflammatory reaction was confined to the mucosa. the submucosa showed only edema. the shigellae were found predominantly in the columnar cells of the surface epithelium, less frequently in those of the crypt, and least frequently in the lamina propria. shigella bacilli invaded the columnar ... | 1982 | 6755871 |
| [case of vulvovaginitis due to shigella flexneri 2a]. | 1982 | 6818298 | |
| bacteriophage mu d1(apr lac) generates vir-lac operon fusions in shigella flexneri 2a. | previous studies have demonstrated that expression of virulence in shigella spp. is controlled by growth temperature. to study the regulation of virulence (vir) genes, we set out to develop a rapid, easily-assayed phenotype with which to measure expression of virulence. this report described a procedure for isolating vir-lac operon fusions in s. flexneri 2a by using the specialized transducing bacteriophage mu d1(apr lac) of casadaban and cohen (m. casadaban and s. n. cohen, proc. natl. acad. sc ... | 1984 | 6236150 |
| temperature-dependent expression of virulence genes in shigella species. | the pathogenicity of shigella spp. involves the ability of the bacteria to penetrate and replicate within the epithelial cells of the large intestine. model systems for examining the virulence of shigellae employ henle intestinal epithelial cells in tissue culture and an in vivo assay for virulence in guinea pig eyes (sereny test). using these systems, we studied the genetic and physiological bases for the ability of shigellae to invade epithelial cells. we found that expression of virulence in ... | 1984 | 6360895 |
| loss of pigmentation in shigella flexneri 2a is correlated with loss of virulence and virulence-associated plasmid. | in this study, we examined the relationship between the virulence of shigella flexneri 2a and the ability of strains of s. flexneri 2a to absorb congo red. spontaneous nonpigmented (i.e., unable to bind congo red [pcr-]) derivatives of a virulent, pigmented (pcr+) strain of s. flexneri 2a were isolated and assayed for virulence as determined by their ability to invade epithelial cells. all pcr- mutants examined lost the ability to invade epithelial cells and were thus avirulent. agarose gel elec ... | 1984 | 6360906 |
| [interrelation of virulent and avirulent (vaccinal) strains of shigella flexneri 2a in long-term bacterial carriage in gnotobiotic rats]. | the ability of s. flexneri 2a virulent and avirulent (vaccine) strains no. 516 and no. 516 m to displace one another during long-term carrier state in germ-free rats has been studied. the long-term persistence of the vaccine strain in the intestine of the rats has been shown to produce colonization resistance to subsequent infection with the virulent culture of these bacteria. during carrier state in rats progressive s--r dissociation of the bacteria occurs, type ii antigen is lost with simultan ... | 1984 | 6375221 |
| oral vaccination of monkeys with an invasive escherichia coli k-12 hybrid expressing shigella flexneri 2a somatic antigen. | a living oral vaccine, designed to protect against shigella flexneri 2a infections, was constructed by using escherichia coli k-12 as a carrier strain. the hybrid strain, designated ec104, contained both chromosomal and plasmid genes from s. flexneri donor strains. in addition to expressing the s. flexneri 2a somatic antigen, it had inherited the property of epithelial-cell invasion. after the oral administration to rhesus monkeys, ec104 was isolated from the feces for up to 3 days, but by day 4 ... | 1984 | 6389344 |
| determination of humoral antibodies against shigella flexneri 2a t32 (istrati) by elisa. | 1984 | 6400300 | |
| improvement of production and control methods of live dysentery vaccine vadizen (shigella flexneri 2a t32-istrati). | 1984 | 6400311 | |
| [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 |
| [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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |