| western blotting analysis of heat shock proteins of rickettsiales and other eubacteria. | heat shock proteins (hsp) of four rickettsia species, three bartonella species, two ehrlichia species, orientia tsutsugamushi and seventeen other eubacterial species were characterized by the enhanced chemiluminescence western blotting (wb) technique with antibodies raised against recombinant hsp from escherichia coli and purified groes from r. typhi. although e. coli dnak and groel have epitopes that are highly conserved among the homologous proteins found in rickettsia, ehrlichia, o. tsutsugam ... | 1998 | 9809424 |
| protein deficiency in a colony of western lowland gorillas (gorilla g. gorilla) | a syndrome of alopecia and weight loss in a colony of 10 western lowland gorillas (gorilla gorilla gorilla) in gabon during a 3-yr period was apparently due to a dietary protein deficiency, with nine individuals affected to some extent. the most severely afflicted was a 4-yr-old female who eventually died as a result of acute gastroenteritis caused by shigella flexneri. clinical signs included chronic alopecia, hair discoloration, failure to thrive, and weight loss, and their severity was direct ... | 1998 | 9809596 |
| drug resistance of shigella strains isolated in ankara, turkey, 1993-1996. | 289 shigella strains were isolated from children at the paediatrics department of ankara university. 75% of the isolates were s. sonnei and 24.8% were s. flexneri. each strain was tested for resistance to 9 antimicrobial agents. 79% of the isolates were resistant to streptomycin (s), 56% to tetracycline (t), 55.7% to trimethoprim-sulfamethoxazole (sxt), 27.7% to ampicillin (am) and 19.7% to chloramphenicol (c). none of the isolates was resistant to ciprofloxacin, nalidixic acid, cephalothin, amp ... | 1998 | 9817513 |
| interferon alpha inhibits a src-mediated pathway necessary for shigella-induced cytoskeletal rearrangements in epithelial cells. | shigella flexneri, the causative agent of bacillary dysentery, has the ability to enter nonphagocytic cells. the interferon (ifn) family of cytokines was found to inhibit shigella invasion of cultured epithelial cells. we show here that ifn-alpha inhibits a src-dependent signaling cascade triggered by shigella that leads to the reorganization of the host cell cytoskeleton. immunofluorescence studies showed that ifn-alpha inhibits shigella-induced actin polymerization required for bacterial entry ... | 1998 | 9817757 |
| shigella infection as observed in the experimentally inoculated domestic pig, sus scrofa domestica. | the domestic pig, sus scrofa domestica, was investigated as a potential animal model for shigellosis. we examined the effects of pig age, pig breed and antibiotic pretreatment upon shigella infection. shigella dysenteriae, and shigella flexneri (both virulent and avirulent strains) were utilized. our results indicated that young (4-week-old), conventionally re ared, domestic pigs were routinely, but briefly, colonized (average=3.5+/-2.5 days) following oral or gavage administration ofs. flexneri ... | 1998 | 9817822 |
| structural features, physiological roles, and biotechnological applications of the membrane proteases of the ompt bacterial endopeptidase family: a micro-review. | the proteins of the ompt family represent a new class of integral membrane peptidases showing no sequence homology with other known classes of proteases. the prototype of the family, the escherichia coli k-12 protein ompt (or omptin), is an outer membrane endopeptidase with unusual specificity: it cleaves the peptide bond between two basic amino acids. a second distinct characteristic of ompt is its ability to function even under extreme denaturing conditions (e.g. high concentration of urea). t ... | 1998 | 9829254 |
| thermoregulation of shigella and escherichia coli eiec pathogenicity. a temperature-dependent structural transition of dna modulates accessibility of virf promoter to transcriptional repressor h-ns. | the expression of plasmid-borne virf of shigella encoding a transcriptional regulator of the arac family, is required to initiate a cascade of events resulting in activation of several operons encoding invasion functions. h-ns, one of the main nucleoid-associated proteins, controls the temperature-dependent expression of the virulence genes by repressing the in vivo transcription of virf only below a critical temperature (approximately 32 degrees c). this temperature-dependent transcriptional re ... | 1998 | 9843508 |
| index of suspicion. case 2. diagnosis: bacillary dysentery and campylobacter infections. | | 1998 | 9849074 |
| multiresistant shigella species isolated from pediatric patients with acute diarrheal disease. | a total of 57 strains of shigella (36 s sonnei, 21 s flexneri), isolated from children with acute diarrheal disease who presented for treatment at the andes university hospital, merida, venezuela, from june 1993 to june 1995, were tested for their susceptibility to trimethoprim, sulfamethoxazole, ampicillin, cefamandole, ceftriaxone, streptomycin, fleroxacin, and nalidixic acid, by the agar dilution method. twenty-seven strains (75%) of s sonnei and eight strains of s flexneri (38.1%) isolates s ... | 1998 | 9856691 |
| peripheral blood cd14(+) cells from healthy subjects carry a circular conformation of latent cytomegalovirus genome. | the majority of the human population harbors latent cytomegalovirus. although cd14(+) peripheral blood mononuclear cells have been implicated as sites of latency, the conformation of the latent viral genome in these cells is unknown. in this study, the conformation of viral genomic dna was assessed in cd14(+) cells from healthy virus seropositive carriers using an electrophoretic separation on native agarose gels in combination with polymerase chain reaction detection. here we show that the vira ... | 1999 | 9864186 |
| establishment of unipolar localization of icsa in shigella flexneri 2a is not dependent on virulence plasmid determinants. | unipolar localization of icsa on the surface of shigella flexneri is required for efficient formation of actin tails and protrusions in infected eucaryotic cells. lipopolysaccharide (lps) mutations have been demonstrated to affect either the establishment or the maintenance of icsa in a unipolar location, although the mechanism is unknown. in order to analyze the contribution of virulence plasmid determinants on the unipolar localization of icsa, we examined the localization of icsa expressed fr ... | 1999 | 9864236 |
| psa causes oncogenic suppression of agrobacterium by inhibiting vire2 protein export. | when coresident with the ti (tumor-inducing) plasmid, the 21-kda product of the osa gene of the plasmid psa can suppress crown gall tumorigenesis incited by agrobacterium tumefaciens. neither t-dna processing nor vir (virulence) gene induction is affected by the presence of osa in the bacterium. we used arabidopsis thaliana root segments and tobacco leaf discs to demonstrate that osa inhibits a. tumefaciens from transforming these plants to the stable phenotypes of tumorigenesis, kanamycin resis ... | 1999 | 9864329 |
| shigella and the fluorinated quinolones. | between july 1996 to june 1997 a total of 531 stool samples from cases of acute diarrhoea, dysentry, colitis admitted to kasturba medical college hospital, manipal were investigated. shigella were isolated from 29 samples (5.46%). out of them, shigella flexneri were 16 (55.17%), shigella boydii 8 (27.58%), shigella dysentriae 3 (10.34%) and shigella sonnei 2 (6.89%). five strains of shigella flexneri and one strain of shigella dysentriae were found to show resistance to nalidixic acid and the ne ... | 1998 | 9866907 |
| novel combination of mutations in the dna gyrase and topoisomerase iv genes in laboratory-grown fluoroquinolone-resistant shigella flexneri mutants. | | 1998 | 9867794 |
| short-chain fatty acids improve clinical, pathologic, and microbiologic features of experimental shigellosis. | because of the metabolic and antibacterial actions of short-chain fatty acids (scfa), their roles in modifying the clinicopathologic features of shigellosis were evaluated in a rabbit model of shigellosis. acute colitis was induced in adult rabbits by intracolonic administration of shigella flexneri 2a. after 24 h, rabbits were given 6-h colonic infusions of scfa (acetate, propionate, n-butyrate; 60:30:40 mm) or scfa-free solution (control); groups of rabbits were killed in batches of 2 or 3 ani ... | 1999 | 9878023 |
| the trithorax group gene osa encodes an arid-domain protein that genetically interacts with the brahma chromatin-remodeling factor to regulate transcription. | the trithorax group gene brahma (brm) encodes the atpase subunit of a chromatin-remodeling complex involved in homeotic gene regulation. we report here that brm interacts with another trithorax group gene, osa, to regulate the expression of the antennapedia p2 promoter. regulation of antennapedia by brm and osa proteins requires sequences 5' to the p2 promoter. loss of maternal osa function causes severe segmentation defects, indicating that the function of osa is not limited to homeotic gene re ... | 1999 | 9895321 |
| characterization of the avian pathogenic escherichia coli hemagglutinin tsh, a member of the immunoglobulin a protease-type family of autotransporters. | we reported earlier that a single gene, tsh, isolated from a strain of avian pathogenic escherichia coli (apec) was sufficient to confer on e. coli k-12 a hemagglutinin-positive phenotype and that the deduced sequence of the tsh protein shared homology to the serine-type immunoglobulin a (iga) proteases of neisseria gonorrhoeae and haemophilus influenzae. in this report we show that e. coli k-12 containing the recombinant tsh gene produced two proteins, a 106-kda extracellular protein and a 33-k ... | 1999 | 9916089 |
| strategy for cross-protection among shigella flexneri serotypes. | based upon the lipopolysaccharide (lps) structure and antigenicity of shigella group b, a strategy for broad cross-protection against 14 shigella flexneri serotypes was designed. this strategy involves the use of two s. flexneri serotypes (2a and 3a), which together bear the all of the major antigenic group factors of this group. the novel attenuated strains used in these studies were s. flexneri 2a strain cvd 1207 (deltaguab-a deltavirg deltaset1 deltasen) and s. flexneri 3a strain cvd 1211 (de ... | 1999 | 9916090 |
| protein-protein interactions in the assembly of shigella flexneri invasion plasmid antigens ipab and ipac into protein complexes. | shigella flexneri is a facultative intracellular bacterial pathogen that invades human colonic epithelial cells by a process called pathogen-induced phagocytosis. pathogen entry requires three virulence plasmid-encoded proteins called invasion plasmid antigens (ipa) b, c and d which are secreted upon bacterial contact with a host cell. following their secretion, ipab and ipac are found within a complex of proteins that may also contain ipaa and ipad. previous work has shown that exogenously adde ... | 1998 | 9920383 |
| functional analysis of a rickettsial ompa homology domain of shigella flexneri icsa. | shigella flexneri is a gram-negative bacterium that causes diarrhea and dysentery by invasion and spread through the colonic epithelium. bacteria spread by assembling actin and other cytoskeletal proteins of the host into "actin tails" at the bacterial pole; actin tail assembly provides the force required to move bacteria through the cell cytoplasm and into adjacent cells. the 120-kda s. flexneri outer membrane protein icsa is essential for actin assembly. icsa is anchored in the outer membrane ... | 1999 | 9922250 |
| effect of wzx (rfbx) mutations on a-band and b-band lipopolysaccharide biosynthesis in pseudomonas aeruginosa o5. | the wbp cluster of pseudomonas aeruginosa o5 encodes a number of proteins involved in biosynthesis of the heteropolymeric and wzy-dependent b-band o antigen, including wzy, the o-antigen polymerase, and wzz, the regulator of o-antigen chain length. a gene (formerly wbpf), contiguous with wzy in the wbp cluster, is predicted to encode a highly hydrophobic protein with multiple membrane-spanning domains. this secondary structure is consistent with that of wzx (rfbx), the putative o-antigen unit tr ... | 1999 | 9922263 |
| the spi-3 pathogenicity island of salmonella enterica. | pathogenicity islands are chromosomal clusters of pathogen-specific virulence genes often found at trna loci. we have determined the molecular genetic structure of spi-3, a 17-kb pathogenicity island located at the selc trna locus of salmonella enterica serovar typhimurium. the g+c content of spi-3 (47.5%) differs from that of the salmonella genome (52%), consistent with the notion that these sequences have been horizontally acquired. spi-3 harbors 10 open reading frames organized in six transcr ... | 1999 | 9922266 |
| shigellosis in children: a clinico-epidemiological comparison between shigella dysenteriae type i and shigella flexneri. | we reviewed the clinical and epidemiological features of 390 children under 5 years of age infected with either shigella dysenteriae type i or shigella flexneri attending a diarrhoea treatment centre from 1993 to 1995 in dhaka, bangladesh. older age (24 months or more), underweight and wasting but not stunting were the host factors significantly more associated with shigella dysenteriae type i infection than in shigella flexneri-infected children. moreover, use of antibiotics at home, use of wat ... | 1998 | 9924557 |
| [importance of the eradication of the focus of infection and the synchronized correction of disturbed intestinal microflora in shigellosis patients]. | the dynamic study of the characteristics of serum specific shigella endotoxinemia was carried out in 60 patients with s.flexneri infection by eia techniques. in addition, the level of re-glycolipid in the blood of patients was determined in eia with the use of re-antibodies with the simultaneous study of the rectal microbiocenosis. the degree of dysbiotic disturbances in the intestine was found to be directly related to the levels of lps of s.flexneri 2a o-antigens and re-glycolipid of gram-nega ... | 1998 | 9949508 |
| [modern views on the molecular biological foundations of the pathogenesis of shigella infections]. | | 1998 | 9949517 |
| comparison of survival of diarrhoeagenic agents in two local weaning foods (ogi and koko). | the ph values of both cooked and uncooked ogi and koko samples were determined and the survival rate of four diarrhoeagenic agents, enteroinvasive escherichia coli, salmonella typhi, shigella flexneri, and vibrio cholerae were studied after they were seeded into cooked ogi and koko. analysis of the ph of the cooked inoculated samples showed that there was a slight increase in ph (decrease in acidity) during storage for 48 h and 37 degrees c (from 3.5 to 3.7 for ogi and from 3.7 to 4.1 for koko). ... | 1998 | 9972074 |
| impact of either elevated or decreased levels of cytochrome bd expression on shigella flexneri virulence. | shigella spp. are the major cause of bacillary dysentery worldwide. the pathogenic process involves bacterial invasion and lysis of the phagocytic vacuole, followed by replication and movement within the cell cytoplasm and, ultimately, spread directly into adjacent cells. this study demonstrates that s. flexneri cytochrome bd expression is necessary for normal intracellular survival and virulence. cytochrome bd is one of two terminal oxidases in the bacterial respiratory chain that reduce molecu ... | 1999 | 9973350 |
| mucosal dna vaccine immunization against measles with a highly attenuated shigella flexneri vector. | an intranasal vaccine vector would elicit protective immunity at the respiratory mucosa, the portal of entry and the primary site for replication for measles virus (mv) and other respiratory viruses. in a murine model of pulmonary shigella, we demonstrate here that a candidate-attenuated shigella vaccine vector is safely tolerated in ifn-gamma deficient mice at an inoculum that is 1 million-fold higher than the inoculum of the wild-type parent strain that would be lethal for greater than 90% of ... | 1999 | 9973419 |
| tetranucleotide repeats identify novel virulence determinant homologues in neisseria meningitidis. | numerous outer membrane components of neisseria meningitidis and n. gonorrhoeae exhibit phase variable expression (the rapid, reversible on/off switching of phenotypic expression). many of the genes encoding these outer membrane components contain simple repetitive dna motifs (mononucleotides, dinucleotides, tetranucleotides and other repeats) which mediate this variation. one such repeat motif, the tetranucleotide 5;-(gcaa)n-3;, is associated with phase-variable lps biosynthetic genes in the pa ... | 1999 | 9973577 |
| identification of shigella flexneri subserotype 1c in rural egypt. | in a population-based study of diarrhea in rural, northern egypt, 60 shigella flexneri strains were identified, of which 10 could not be definitively serotyped. serological analysis with commercial reagents suggested that they were serotype 1, but the strains failed to react with subserotype 1a- or 1b-specific antibodies. all 10 strains reacted with masf 1c, a monoclonal antibody specific for a provisional s. flexneri subserotype, 1c, first identified in bangladesh and not previously detected ou ... | 1999 | 9986881 |
| the virulence plasmid-encoded impcab operon enhances survival and induced mutagenesis in shigella flexneri after exposure to uv radiation. | upon exposure to uv radiation, shigella flexneri sa100 displayed survival and mutation frequencies comparable to those of escherichia coli ab1157, which contains a functional umudc error-prone dna repair system. survival of sa100 after uv irradiation was associated with the presence of the 220-kb virulence plasmid, pvp. this plasmid encodes homologues of impa and impb, which comprise an error-prone dna repair system encoded on plasmid tp110 that was initially identified in salmonella typhimurium ... | 1999 | 10024589 |
| interleukin-8 controls bacterial transepithelial translocation at the cost of epithelial destruction in experimental shigellosis. | in shigellosis, the network of cellular interactions mediated by a balance of pro- and anti-inflammatory cytokines or chemokines is clearly tipped toward acute destructive inflammation of intestinal tissues by the bacterial invader. this work has addressed the role played by interleukin-8 (il-8) in a rabbit model of intestinal invasion by shigella flexneri. il-8, which is largely produced by the epithelial cells themselves, appears to be a major mediator of the recruitment of polymorphonuclear l ... | 1999 | 10024597 |
| relationship between o-serogroup and presence of pathogenic factor genes in escherichia coli. | a total of 383 isolates of serogroup-based enteropathogenic and enteroinvasive escherichia coli (310 strains of epec and 73 strains of eiec) were examined for the presence of corresponding pathogenic genes. the serogroup-based epec consisted of 232 strains isolated from diarrhea patients and of 78 strains from healthy carriers. the gene encoding intimin, eaea, was detected in 42 of the 232 epec strains from patients (18.1%) and 9 of the 78 strains from carriers (11.5%). the difference was not si ... | 1998 | 10037219 |
| mechanism of shigella entry into epithelial cells. | shigella, the causative agent of bacillary dysentery, invades epithelial cells by reorganizing the cell cytoskeleton during bacterial entry. this entry process requires the shigella ipa proteins that are secreted by a type iii secretion apparatus and that act in concert to fine tune cell responses. actin polymerization at the site of entry is dependent on the ipab and ipac proteins, whereas ipaa further modulates cytoskeletal rearrangements by binding to vinculin. | 1999 | 10047558 |
| antibiotic susceptibilities and plasmid profiles of shigella flexneri isolates from children with diarrhoea in islamabad, pakistan. | | 1998 | 10052914 |
| enterobacteria in reactive arthritis: yersinia, shigella, and salmonella. | | 1999 | 10063518 |
| molecular bases of epithelial cell invasion by shigella flexneri. | the pathogenesis of shigellosis is characterized by the capacity of the causative microorganism, shigella, to invade the epithelial cells that compose the mucosal surface of the colon in humans. the invasive process encompasses several steps which can be summarized as follows: entry of bacteria into epithelial cells involves signalling pathways that elicit a macropinocitic event. upon contact with the cell surface, s. flexneri activates a mxi/spa secretory apparatus encoded by two operons compri ... | 1998 | 10081579 |
| the mxi-spa type iii secretory pathway of shigella flexneri requires an outer membrane lipoprotein, mxim, for invasin translocation. | invasion of epithelial cells by shigella flexneri is mediated by a set of translocated bacterial invasins, the ipa proteins, and its dedicated type iii secretion system, called mxi-spa. we show here that mxim, part of the mxi-spa locus in the s. flexneri virulence plasmid, encodes an indispensable type iii secretion apparatus component, required for both ipa translocation and tissue culture cell invasion. we demonstrated that mature mxim, first identified as a putative lipoprotein, is lipidated ... | 1999 | 10085046 |
| adaptive immune response to shigella flexneri 2a cydc in immunocompetent mice and mice lacking immunoglobulin a. | shigella flexneri cydc, which is deficient in cytochrome bd, was rapidly cleared from the lungs of intranasally inoculated mice and was sereny negative, yet it induced 93% protection against challenge with wild-type s. flexneri. mice that lack immunoglobulin a (iga) were fully protected, suggesting that iga may not be required for adaptive immunity in this model system. | 1999 | 10085048 |
| shigella infection in macaque colonies: case report of an eradication and control program. | a primate colony comprising three distinct but interrelated units had long-term history of undiagnosed diarrhea and associated deaths for many years. in 1989, the clinical problem was recognized as a confounding factor for the experimental work, and steps were taken to eradicate the disease. this was done by a combined approach involving improved sample collection techniques and microbiological methods, treatment of all animals in the colony, and improvement in management. these management chang ... | 1998 | 10090037 |
| role of the s. typhimurium actin-binding protein sipa in bacterial internalization. | entry of the bacterium salmonella typhimurium into host cells requires membrane ruffling and rearrangement of the actin cytoskeleton. here, it is shown that the bacterial protein sipa plays a critical role in this process. sipa binds directly to actin, decreases its critical concentration, and inhibits depolymerization of actin filaments. these activities result in the spatial localization and more pronounced outward extension of the salmonella-induced membrane ruffles, thereby facilitating bact ... | 1999 | 10092234 |
| binding site recognition by rns, a virulence regulator in the arac family. | the expression of cs1 pili by enterotoxigenic strains of escherichia coli is regulated at the transcriptional level and requires the virulence regulator rns, a member of the arac family of regulatory proteins. rns binds at two separate sites upstream of pcoo (the promoter of cs1 pilin genes), which were identified in vitro with an mbp::rns fusion protein in gel mobility and dnase i footprinting assays. at each site, rns recognizes asymmetric nucleotide sequences in two regions of the major groov ... | 1999 | 10094688 |
| killed oral shigella vaccine made from shigella flexneri 2a protects against challenge in the rabbit model of shigellosis. | the protective efficacy of an orally administered heat-killed virulent strain of shigella flexneri 2a (5 weekly oral doses) was evaluated in 25 rabbits (14 immunized and 11 non-immunized controls) against challenge with the same strain of shigella using the rabbit model of shigellosis. all 11 non-immunized rabbits developed bloody diarrhoea following challenge and 6 (54%) died. none of the 14 immunized rabbits developed diarrhoea (all had pellet stools) but 3 (21%) died from causes not associate ... | 1999 | 10102148 |
| rupture of the intestinal epithelial barrier and mucosal invasion by shigella flexneri. | invasion of the intestinal barrier by shigella flexneri involves complex interactions with epithelial and phagocytic cells. major perturbation of the signals that maintain epithelial integrity permits mucosal invasion, leading to tissue destruction. expression of this invasive phenotype depends on the secretion of ipa proteins (invasins), which can trigger entry of the pathogen into epithelial cells by causing massive rearrangement of the host cell cytoskeleton and cause macrophage apoptotic dea ... | 1999 | 10194063 |
| [the efficacy of intetrix in the combined treatment of patients with shigelloses]. | efficacy was studied of intetrix in the treatment of acute sonnei's shigellosis and flexner's shigellosis in 32 patients presenting with mild and moderately severe course of their illness. the intretrix group patients fared better compared with controls who received furazolidon as an etiotropic drug, with the duration of intoxication symptoms getting shorter, abdominal pains and diarrhea subsiding. intetrix tended to be associated with a lower incidence of unfavourable outcomes, both immediate a ... | 1998 | 10204377 |
| inducible acid tolerance mechanisms in enteric bacteria. | enteric micro-organisms have developed several inducible mechanisms for surviving transient periods of extreme acid stress. salmonella typhimurium possesses an acid tolerance response (atr) induced in minimal medium by short exposures to mild acid stress. more than 50 acid shock proteins (asps) are induced during adaptation. eight asps are regulated by the major iron regulatory protein, fur, in an unusual iron-independent manner. the two-component regulator, phop, is an autoinduced asp that cont ... | 1999 | 10207913 |
| prevalence, in-vitro secretory activity, and cytotoxicity of aeromonas species associated with childhood gastroenteritis in chennai (madras), india. | an investigation on the prevalence of aeromonas in gastrointestinal illnesses of pediatric inpatients 1 month to 3 years of age was conducted from february 1997 through january 1998 in madras. sixteen aeromonas spp. were isolated from 11 male and five female children among the 341 pediatric inpatients suffering from acute diarrhoea. a. caviae, which was isolated from nine cases, was found to be the most predominant isolate, followed by a. veronii biovar sobria, isolated from six cases, and a. hy ... | 1998 | 10211427 |
| n-wasp is an important protein for the actin-based motility of shigella flexneri in the infected epithelial cells. | | 1998 | 10211437 |
| pathogenesis of shigellosis: from molecular and cellular biology of epithelial cell invasion to tissue inflammation and vaccine development. | | 1998 | 10211438 |
| enteropathogenic e. coli, salmonella, and shigella: masters of host cell cytoskeletal exploitation. | bacterial pathogens have evolved numerous strategies to exploit their host's cellular processes so that they can survive and persist. often, a bacterium must adhere very tightly to the cells and mediate its effects extracellularly, or it must find a way to invade the host's cells and survive intracellularly. in either case, the pathogen hijacks the host's cytoskeleton. the cytoskeleton provides a flexible framework for the cell and is involved in mediating numerous cellular functions, from cell ... | 1999 | 10221873 |
| safety and immunogenicity of shigella sonnei and shigella flexneri 2a o-specific polysaccharide conjugates in children. | o-specific polysaccharide conjugates of shigellae were safe and immunogenic in young adults, and a shigella sonnei conjugate conferred protection [1-3]. shigellosis is primarily a disease of children; therefore, the safety and immunogenicity of s. sonnei and shigella flexneri 2a conjugates were studied in 4- to 7-year-old children. local and systemic reactions were minimal. the first injection of both conjugates elicited significant rises in geometric mean levels of serum igg only to the homolog ... | 1999 | 10228084 |
| the unipolar shigella surface protein icsa is targeted directly to the bacterial old pole: icsp cleavage of icsa occurs over the entire bacterial surface. | shigella flexneri is an intracellular pathogen that is able to move within the cytoplasm of infected cells by the continual assembly of actin onto one pole of the bacterium. icsa, an outer membrane protein, is localized to the old pole of the bacterium and is both necessary and sufficient for actin assembly. icsa is slowly cleaved from the bacterial surface by the protease icsp (sopa). absence of icsp leads to an alteration in the distribution of surface icsa, such that the polar cap is maintain ... | 1999 | 10231492 |
| shigella flexneri ysh6000 induces two types of cell death, apoptosis and oncosis, in the differentiated human monoblastic cell line u937. | shigella flexneri, but not a non-invasive mutant derivative rapidly induced cell death in human monoblastic u937 cells as well as in differentiated cells pretreated with interferon-gamma (ifn gamma) or retinoic acid (ra). we investigated the morphological and biochemical characteristics of bacterial invasion-induced cell death in these differentiated u937 cells. ifn gamma-differentiated cells showed morphological changes typical of apoptosis and their dna was cleaved giving a ladder-like electro ... | 1999 | 10234825 |
| a comparative study of the actin-based motilities of the pathogenic bacteria listeria monocytogenes, shigella flexneri and rickettsia conorii. | listeria monocytogenes, shigella flexneri, and rickettsia conorii are three bacterial pathogens that are able to polymerize actin into 'comet tail' structures and move within the cytosol of infected cells. the actin-based motilities of l. monocytogenes and s. flexneri are known to require the bacterial proteins acta and icsa, respectively, and several mammalian cytoskeleton proteins including the arp2/3 complex and vasp (vasodilator-stimulated phosphoprotein) for l. monocytogenes and vinculin an ... | 1999 | 10318762 |
| trafficking of shigella lipopolysaccharide in polarized intestinal epithelial cells. | bacterial lipopolysaccharide (lps) at the apical surface of polarized intestinal epithelial cells was previously shown to be transported from the apical to the basolateral pole of the epithelium (beatty, w.l., and p.j. sansonetti. 1997. infect. immun. 65:4395-4404). the present study was designed to elucidate the transcytotic pathway of lps and to characterize the endocytic compartments involved in this process. confocal and electron microscopic analyses revealed that lps internalized at the api ... | 1999 | 10330399 |
| the effectiveness of triclosan-incorporated plastic against bacteria on beef surfaces. | triclosan is a nonionic, broad-spectrum, antimicrobial agent that has been incorporated into a variety of personal hygiene products, including hand soaps, deodorants, shower gels, mouthwashes, and toothpastes. in this study, plastic containing 1,500 ppm of triclosan was evaluated in plate overlay assays and meat experiments as a means of reducing populations of bacteria. plate overlay assays indicated that the triclosan-incorporated plastic (tip) inhibited the following organisms: brochothrix th ... | 1999 | 10340667 |
| [lipopolysaccharide from photosynthetic bacteria blocks ca2+ response of human neutrophils induced by endotoxins from shigella flexneri and its re-mutant]. | | 1999 | 10347828 |
| a low rate of nucleotide changes in escherichia coli k-12 estimated from a comparison of the genome sequences between two different substrains. | two genome sequences of escherichia coli k-12 substrains, one partial w3110 and one complete mg1655, have been determined by japanese and american genome projects, respectively. in order to estimate the rate of nucleotide changes, we directly compared 2 mb of the nucleotide sequences from these closely-related e. coli substrains. given that the two substrains separated about 40 years ago, the rate of nucleotide changes was estimated to be less than 10(-7) per site per year. this rate was support ... | 1999 | 10350060 |
| a functional role for ezrin during shigella flexneri entry into epithelial cells. | shigella flexneri is an enteroinvasive bacterium responsible for bacillary dysentery in humans. bacterial entry into epithelial cells is a crucial step for the establishment of the infection. it is characterized by a transient reorganization of the host cell cytoskeleton at the site of bacterial interaction with the cell membrane, which leads to bacterial engulfment by a macropinocytic process. we show in this study that the membrane-cytoskeleton linker, ezrin, a member of the erm (ezrin, radixi ... | 1999 | 10362536 |
| rho family gtpases control entry of shigella flexneri into epithelial cells but not intracellular motility. | shigella flexneri, an invasive bacterial pathogen, promotes formation of two cytoskeletal structures: the entry focus that mediates bacterial uptake into epithelial cells and the actin-comet tail that enables the bacteria to spread intracellularly. during the entry step, secretion of bacterial invasins causes a massive burst of subcortical actin polymerization leading the formation of localised membrane projections. fusion of these membrane ruffles leads to bacterial internalization. inside the ... | 1999 | 10362537 |
| an untypeable shigella flexneri strain associated with an outbreak in california. | eleven shigella flexneri (group b) isolates were recovered from epidemiologically linked patrons and food handlers from a restaurant-associated outbreak of shigellosis. six isolates available for pulsed-field gel electrophoresis were identical. all strains agglutinated in group b and subgroup factor 6 sera but not in group 1 through group 6 sera. | 1999 | 10364614 |
| functional analysis of the o antigen glucosylation gene cluster of shigella flexneri bacteriophage sfx. | previous studies have shown that shigella flexneri bacteriophage x (sfx) encodes a glucosyltransferase (gtrx, formerly gtr), which is involved in o antigen modification (serotype y to serotype x). however, gtrx alone can only mediate a partial conversion. more recently, a three-gene cluster has been identified next to the attachment site in the genome of two other s. flexneri bacteriophages (i.e. sfv and sfii). this gene cluster was postulated to be responsible for a full o antigen conversion. h ... | 1999 | 10376843 |
| vaccination against shigellosis with attenuated shigella flexneri 2a strain sc602. | the shigella flexneri 2a sc602 vaccine candidate carries deletions of the plasmid-borne virulence gene icsa (mediating intra- and intercellular spread) and the chromosomal locus iuc (encoding aerobactin) (s. barzu, a. fontaine, p. j. sansonetti, and a. phalipon, infect. immun. 64:1190-1196, 1996). dose selection studies showed that sc602 causes shigellosis in a majority of volunteers when 3 x 10(8) or 2 x 10(6) cfu are ingested. in contrast, a dose of 10(4) cfu was associated with transient feve ... | 1999 | 10377124 |
| population-based study of the incidence of shigella diarrhea and causative serotypes in santiago, chile. | shigella is an important cause of diarrheal disease in children in developing countries. the increasing prevalence of antibiotic-resistant strains has stimulated interest in the use of multivalent shigella vaccines. because shigella vaccines under development are based on eliciting immunity to o antigens, monitoring the distribution of serotypes in defined target populations is critical. we initiated health center-based surveillance in a poor semirural community in colina, santiago (7489 childre ... | 1999 | 10391178 |
| 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 |
| the aerobactin iron transport system genes in shigella flexneri are present within a pathogenicity island. | genes encoding the synthesis and transport of aerobactin, a hydroxamate siderophore associated with increased virulence of enteric bacteria, were mapped within a pathogenicity island in shigella flexneri. the island, designated shi-2 for shigella pathogenicity island 2, was located downstream of selc, the site of insertion of pathogenicity islands in several other enteric pathogens. dna sequence analysis revealed the presence of multiple insertion sequences upstream and downstream of the aerobac ... | 1999 | 10411724 |
| 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 |
| thymic independence of adaptive immunity to the intracellular pathogen shigella flexneri serotype 2a. | shigella flexneri is a facultative intracellular pathogen. while immunity to several intracellular pathogens is mediated by t lymphocytes, it is unknown whether cellular immune responses are important to adaptive immunity to s. flexneri. we show that vaccination with s. flexneri serotype 2a confers protection to mice that lack t lymphocytes or gamma interferon (ifn-gamma), specific depletion of t lymphocytes does not alter the protection, and adoptive transfer of splenocytes from vaccinated mice ... | 1999 | 10417163 |
| transcriptional activation of agrobacterium tumefaciens virulence gene promoters in escherichia coli requires the a. tumefaciens rpoa gene, encoding the alpha subunit of rna polymerase. | the two-component regulatory system, composed of vira and virg, is indispensable for transcription of virulence genes within agrobacterium tumefaciens. however, vira and virg are insufficient to activate transcription from virulence gene promoters within escherichia coli cells, indicating a requirement for additional a. tumefaciens genes. in a search for these additional genes, we have identified the rpoa gene, encoding the alpha subunit of rna polymerase (rnap), which confers significant expres ... | 1999 | 10419950 |
| serotype 1a o-antigen modification: molecular characterization of the genes involved and their novel organization in the shigella flexneri chromosome. | the factors responsible for serotype 1a o-antigen modification in shigella flexneri were localized to a 5.8-kb chromosomal hindiii fragment of serotype 1a strain y53. the entire 5.8-kb fragment and regions up- and downstream of it (10.6-kb total) were sequenced. a putative three-gene operon, which showed homology with other serotype conversion genes, was identified and shown to confer serotype 1a o-antigen modification. the serotype conversion genes were flanked on either side by phage dna. mult ... | 1999 | 10419979 |
| antimicrobial activity of byrsonima crassifolia (l.) h.b.k. | from byrsonima crassifolia (l.) h.b.k. a tropical tree widely distributed in mexico, central and south america, which has been used medicinally since prehispanic times, we report here the antibacterial activities of organic extracts of roots and stems. the ethyl acetate of roots was the most active against klebsiella pneumoniae, pseudomonas aeruginosa, salmonella typhi, shigella flexneri, staphylococcus aureus, staphylococcus epididermis, streptococcus pneumoniae and micrococcus luteus. | 1999 | 10432211 |
| [in vitro activity of trovafloxacin, of other fluoroquinolones and of related antimicrobials against clinical isolates. grupo colaborativo whonet-argentina]. | the in vitro activity of trovafloxacin (trv) has been evaluated in comparison with that of other antimicrobial agents against 5671 clinical isolates recovered by representative institutions of different provinces in our country. the resistance percentage to gentamicin and third generation cephalosporins among enterobacteriaceae was high: 17% and 16% respectively, with a considerable variation according to the analyzed species. the resistance to ciprofloxacin (cip) and trv affected approximately ... | 1999 | 10436549 |
| detection of shigella spp. in food with a nested pcr method-sensitivity and performance compared with a conventional culture method. | a nested pcr method was developed and its performance evaluated by detection of shigella flexneri in food. the nested pcr amplifies sequences within an invasion-associated locus (ial) on the invasion plasmid specific for shigella and enteroinvasive eschrichia coli (eiec). the nested pcr detected sh. flexneri in lettuce inoculated with 2, 20 and 200 cfu g-1 after 1, 7 and 18 d of storage, respectively. in comparison, a culture method (nmkl no. 151) detected 10(5) cfu g-1 after 1 but not after 7 d ... | 1999 | 10438226 |
| the shigella flexneri bacteriophage sf6 tailspike protein (tsp)/endorhamnosidase is related to the bacteriophage p22 tsp and has a motif common to exo- and endoglycanases, and c-5 epimerases. | the temperate bacteriophage sf6 infects shigella flexneri strains of serotype x or y, converting them into serotypes 3a or 3b, respectively. the tailspike protein (tsp) of sf6 possesses endo-1,3-alpha-l-rhamnosidase (endorhamnosidase) activity which results in cleavage of the lipopolysaccharide o-antigen receptor during the adsorption of the phage to the cell surface. when used in southern hybridization, a p22 gene 9 (encoding p22 tsp) dna probe hybridized with restriction fragment pstl-7 of sf6 ... | 1999 | 10439404 |
| novel self-sampling culture method to monitor excretion of live, oral shigella flexneri 2a vaccine sc602 during a community-based phase 1 trial. | a culture technique for assessing the excretion of live enteric vaccines was developed and verified during an outpatient safety trial of the shigella flexneri 2a sc602 vaccine. preliminary studies showed that sc602 could be recovered on hektoen enteric (he) agar plates that had been inoculated with seeded stools in one quadrant, held for up to 48 hours, streaked for isolation, and incubated for 24 +/- 6 hours. recovery results on he plates held at 4 degrees c and 25 degrees c were comparable; ho ... | 1999 | 10444027 |
| identification of bacterial proteins observed in maldi tof mass spectra from whole cells. | characteristic ions in the maldi tof mass spectra from bacterial cells have been associated with four known proteins. the proteins, observed both from cells and in filtered cellular suspensions, were isolated by hplc and identified on the basis of their mass spectra and their partial amino acid sequence, determined using the edman method (10-15 residues). the acid resistance proteins hdea and hdeb give rise to ions near m/z 9735 and 9060 in maldi tof mass spectra from cells and from extracts of ... | 1999 | 10450164 |
| immune response to rotavirus vp4 expressed in an attenuated strain of shigella flexneri. | an attenuated strain of shigella flexneri was utilised to express viral protein (vp) 4 of rotavirus and the immunogenicity of the recombinant constructs was studied in balb/c mice. vp4 was expressed as a fusion with maltose binding protein (mbp) in both the cytoplasm and periplasm, with a much higher level of expression occurring in the former. while all constructs induced a shigella-specific response in mice, only the construct expressing mbp-vp4 in the cytoplasm of shigella stimulated an immun ... | 1999 | 10459583 |
| quantitative analysis of igg class and subclass and iga serum response to shigella sonnei and shigella flexneri 2a polysaccharides following vaccination with shigella conjugate vaccines. | it has been recently reported that a conjugate vaccine composed of the o-specific polysaccharide of s. sonnei bound to pseudomonas aeruginosa recombinant exoprotein a (repa) conferred 74% protection against s. sonnei shigellosis. in the present study affinity purified shigella antibodies were used as standards to quantify and characterize the serum antibody response to vaccination with shigella sonnei or shigella flexneri 2a polysaccharide conjugated to repa. the geometric mean concentrations of ... | 1999 | 10462247 |
| 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 |
| [kaopectate in the combined treatment of patients with intestinal infections]. | the paper presents results of multiple-modality treatment of patients with acute intestinal infections with making use of the drug preparation kaopectate incorporating activated attapulgite which is a natural mixture of hydrates of magnesium silicate and silicate of alumina. the above drug has been shown to be endowed with a antidiarrheal and detoxifying activities. | 1999 | 10474963 |
| comparative value of colonic biopsy and intraluminal fluid culture for diagnosis of bacterial acute colitis in immunocompetent patients. infectious colitis study group. | we compared the yield of intraluminal fluid culture to that of biopsy specimens obtained during colonoscopy for the diagnosis of bacterial colitis in 93 immunocompetent patients with a recent episode of diarrhea and macroscopic lesions of colitis. stool culture findings were also available for 68 patients. at least one bacterial pathogen was isolated from the biopsy specimen, intraluminal fluid, or stool from 48 patients (51.6%). salmonella species, clostridium difficile, klebsiella oxytoca, shi ... | 1999 | 10476742 |
| apoptosis of murine peritoneal macrophages induced by an avian pathogenic strain of escherichia coli. | the mechanisms used by avian strains of escherichia coli to invade the respiratory epithelia, leading to septicemia in poultry, are not well-established. in this work, we show that resident murine peritoneal macrophages infected in vitro with an avian strain of e. coli underwent apoptosis 4 h after infection (55.6% of apoptosis in infected cells versus 3.5% in non-infected cells). heat-inactivated bacteria did not induce apoptosis and the inhibition of phagocytosis by pretreatment of cells with ... | 1999 | 10481089 |
| typing and characterization of mechanisms of resistance of shigella spp. isolated from feces of children under 5 years of age from ifakara, tanzania. | eighty-six strains of shigella spp. were isolated during the dry season from stool samples of children under 5 years of age in ifakara, tanzania. the epidemiological relationship as well as the antimicrobial susceptibility and mechanisms of resistance to ampicillin, chloramphenicol, and co-trimoxazole were investigated. four different epidemiological tools, pulsed-field gel electrophoresis (pfge), repetitive extragenic palindromic (rep)-pcr, plasmid analysis, and antibiogram, were compared for t ... | 1999 | 10488163 |
| activation of the cdc42 effector n-wasp by the shigella flexneri icsa protein promotes actin nucleation by arp2/3 complex and bacterial actin-based motility. | to propel itself in infected cells, the pathogen shigella flexneri subverts the cdc42-controlled machinery responsible for actin assembly during filopodia formation. using a combination of bacterial motility assays in platelet extracts with escherichia coli expressing the shigella icsa protein and in vitro analysis of reconstituted systems from purified proteins, we show here that the bacterial protein icsa binds n-wasp and activates it in a cdc42-like fashion. dramatic stimulation of actin asse ... | 1999 | 10491394 |
| treatment with succinic anhydride improves the immunogenicity of shigella flexneri type 2a o-specific polysaccharide-protein conjugates in mice. | seroepidemiological data and a clinical trial with a shigella sonnei o-specific polysaccharide (o-sp)-pseudomonas aeruginosa recombinant exoprotein a (repa) conjugate provide evidence that a critical level of immunoglobulin g (igg) lipopolysaccharide (lps) antibodies in serum confers protection against shigellosis. we evaluated the immunogenicity of conjugates whose carrier proteins and o-sps were treated with succinic anhydride (sa), which reacts with amino groups at neutral ph to form amide-li ... | 1999 | 10496944 |
| preincubation of recombinant ipa proteins of shigella sonnei promotes entry of non-invasive escherichia coli into hela cells. | invasion plasmid antigens of shigella sonnei, ipab, c, d, were expressed as fusion proteins either with maltose-binding protein (mbp) or strept-tag sequence. affinity-purified ipab and ipad were separated from mbp by digestion with factor xa. recombinant ipac having strept-tag sequence at its c-terminal was also purified by avidin affinity column chromatography. these recombinant proteins showed the ability to cause non-invasive escherichia coli k-12 to internalize hela cell only when all of the ... | 1999 | 10502463 |
| [the assessment of the course of an infectious process by the membrane status of the peripheral blood lymphocytes]. | lipid peroxidation in lymphocyte membranes is studied in patients with acute viral hepatitis b and b + c and in chronic alcoholics with flexner's dysentery and with uneventful premorbid history. the intensity of lipid peroxidation in lymphocytes was increased, corresponding to the severity and period of infection. the premorbid background and therapy influenced the lymphocyte membrane status, which can serve as an integral indicator of immunological reactivity of the organism. | 1999 | 10502924 |
| global burden of shigella infections: implications for vaccine development and implementation of control strategies. | few studies provide data on the global morbidity and mortality caused by infection with shigella spp.; such estimates are needed, however, to plan strategies of prevention and treatment. here we report the results of a review of the literature published between 1966 and 1997 on shigella infection. the data obtained permit calculation of the number of cases of shigella infection and the associated mortality occurring worldwide each year, by age, and (as a proxy for disease severity) by clinical c ... | 1999 | 10516787 |
| potentiality of tricyclic compound thioridazine as an effective antibacterial and antiplasmid agent. | thioridazine (th), which is therapeutically used in psychiatric patients, was found to possess conspicuous antimicrobial activity when tested against 316 strains belonging to a number of gram positive and gram negative bacteria. although staphylococcus aureus, vibrio chloerae and v. parahaemolyticus were found to be most sensitive, th was highly bactericidal against s. aureus and bacteriostatic for vibrios and other gram negative organisms. in the study of antiplasmid/curing effect of th on twel ... | 1999 | 10522156 |
| prevalence of shigella enterotoxins 1 and 2 among shigella strains isolated from patients with traveler's diarrhea. | shigella spp. are known primarily as a cause of bacillary dysentery. however, in an initial phase, numerous patients exhibit watery diarrhea that may or may not be followed by dysentery. new virulence factors associated with the species of shigella have recently been described. these are enterotoxins 1 and 2 of shigella (shet-1 and shet-2, respectively). the aim of the present study was to determine the prevalence of shet-1 and shet-2 in species of shigella isolated from patients with traveler's ... | 1999 | 10523561 |
| reconstitution of actin-based motility of listeria and shigella using pure proteins. | actin polymerization is essential for cell locomotion and is thought to generate the force responsible for cellular protrusions. the arp2/3 complex is required to stimulate actin assembly at the leading edge in response to signalling. the bacteria listeria and shigella bypass the signalling pathway and harness the arp2/3 complex to induce actin assembly and to propel themselves in living cells. however, the arp2/3 complex alone is insufficient to promote movement. here we have used pure componen ... | 1999 | 10524632 |
| characterization of pic, a secreted protease of shigella flexneri and enteroaggregative escherichia coli. | we have identified and characterized a secreted protein, designated pic, which is encoded on the chromosomes of enteroaggregative escherichia coli (eaec) 042 and shigella flexneri 2457t. the product of the pic gene is synthesized as a 146.5-kda precursor molecule which is processed at the n and c termini during secretion, allowing the release of a mature protein (109.8 kda) into the culture supernatant. the deduced amino acid sequence of pic shows high homology to autotransporter proteins, parti ... | 1999 | 10531204 |
| native and mutant forms of cholera toxin and heat-labile enterotoxin effectively enhance protective efficacy of live attenuated and heat-killed shigella vaccines. | both native and mutant forms of cholera toxin (ct) and heat-labile enterotoxin (lt) are effective adjuvants for antigens and killed whole-cell preparations. to determine whether these toxin molecules could also boost the immunogenicity and efficacy of live attenuated vaccines directed against shigellosis, the guinea pig keratoconjunctivitis model was used to evaluate the adjuvant effect of these toxin molecules on ecsf2a-3, a deltavirg deltaarod escherichia coli-shigella flexneri 2a hybrid vacci ... | 1999 | 10531238 |
| analysis of shigella flexneri wzz (rol) function by mutagenesis and cross-linking: wzz is able to oligomerize. | the modal length or degree of polymerization (dp) of the shigella flexneri o-antigen is determined in an unknown manner by the wzz/rol protein. the wzz protein is anchored into the cytoplasmic membrane by two transmembrane domains (tm1 amino acids 32-52; tm2 amino acids 295-315) with the central loop of the protein located in the periplasm. plasmids were constructed encoding hybrid wzz proteins consisting of regions of s. flexneri wzz (wzzsf) and salmonella typhimurium wzz (wzzst). these imparte ... | 1999 | 10540296 |
| binding of the shigella protein ipaa to vinculin induces f-actin depolymerization. | shigella flexneri, the causative agent of bacillary dysentery, enters into epithelial cells by a macropinocytic process. ipaa, a shigella protein secreted upon cell contact, binds to the focal adhesion protein vinculin and is required for efficient bacterial uptake. ipaa was shown here to bind with high affinity to the n-terminal residues 1-265 of vinculin. using co-sedimentation and solid-phase assays, we demonstrated that binding of ipaa to vinculin strongly increases the association of vincul ... | 1999 | 10545097 |
| the tripartite type iii secreton of shigella flexneri inserts ipab and ipac into host membranes. | bacterial type iii secretion systems serve to translocate proteins into eukaryotic cells, requiring a secreton and a translocator for proteins to pass the bacterial and host membranes. we used the contact hemolytic activity of shigella flexneri to investigate its putative translocator. hemolysis was caused by formation of a 25-a pore within the red blood cell (rbc) membrane. of the five proteins secreted by shigella upon activation of its type iii secretion system, only the hydrophobic ipab and ... | 1999 | 10545510 |
| extraintestinal dissemination of salmonella by cd18-expressing phagocytes. | specialized epithelia known as m cells overlying the lymphoid follicles of peyer's patches are important in the mucosal immune system, but also provide a portal of entry for pathogens such as salmonella typhimurium, mycobacterium bovis, shigella flexneri, yersinia enterocolitica and reoviruses. penetration of intestinal m cells and epithelial cells by salmonella typhimurium requires the invasion genes of salmonella pathogenicity island 1 (spi1). spi1-deficient s. typhimurium strains gain access ... | 1999 | 10548107 |
| actin-based motility of vaccinia virus mimics receptor tyrosine kinase signalling. | studies of the actin-based motility of the intracellular pathogens listeria monocytogenes and shigella flexneri have provided important insight into the events occurring at the leading edges of motile cells. like the bacteria listeria and shigella, vaccinia virus, a relative of the causative agent of smallpox, uses actin-based motility to spread between cells. in contrast to listeria or shigella, the actin-based motility of vaccinia is dependent on an unknown phosphotyrosine protein, but the und ... | 1999 | 10553910 |
| a system for identifying post-invasion functions of invasion genes: requirements for the mxi-spa type iii secretion pathway of shigella flexneri in intercellular dissemination. | invasion and intercellular spread are hallmarks of shigella pathogenicity. invasion of the eukaryotic cell cytosol requires a type iii secretion system (mxi-spa) and its cognate set of secreted ipa invasins. once intracellular, the icsa protein directs a form of actin-based motility that helps to drive intracellular bacterial movement, formation of cellular protrusions and cell-to-cell spread. work in our laboratory has focused on identifying additional factors required for this intercellular fo ... | 1999 | 10564508 |
| salmonella typhimurium leucine-rich repeat proteins are targeted to the spi1 and spi2 type iii secretion systems. | salmonellae encode two virulence-associated type iii secretion systems (ttss) within salmonella pathogenicity islands 1 and 2 (spi1 and spi2). two salmonella typhimurium genes, ssph1 and ssph2, that encode proteins similar to the shigella flexneri and yersinia species ttss substrates, ipah and yopm, were identified. ssph1 and ssph2 are proteins containing leucine-rich repeats that are differentially targeted to the spi1 and spi2 ttss. ssph2 transcription was induced within raw264.7 macrophages, ... | 1999 | 10564523 |