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crystal structure of spa40, the specificity switch for the shigella flexneri type iii secretion system.the pathogenic bacterium shigella flexneri uses a type iii secretion system to inject virulence factors from the bacterial cytosol directly into host cells. the machinery that identifies secretion substrates and controls the export of extracellular components and effector proteins consists of several inner-membrane and cytoplasmic proteins. one of the inner membrane components, spa40, belongs to a family of proteins proposed to regulate the switching of substrate specificity of the export appara ...200818485071
the response of type three secretion system needle proteins mxihdelta5, bsaldelta5, and prgidelta5 to temperature and ph.the type iii secretion system (ttss) is a specialized supramolecular injectisome composed of 25 or more proteins which form basal and extracellular domains and share gross architectural similarities with bacterial flagella. the extracellular component of the "needle complex" is primarily composed of a single monomeric subunit organized in a helical array surrounding a hollow pore and protrudes from the bacterial membrane. it is through this surface appendage that virulence factors are translocat ...200818491382
distinct isoforms of phospholipase a2 mediate the ability of salmonella enterica serotype typhimurium and shigella flexneri to induce the transepithelial migration of neutrophils.salmonella spp. and shigella spp. are responsible for millions of cases of enteric disease each year worldwide. while these pathogens have evolved distinct strategies for interacting with the human intestinal epithelium, they both induce significant proinflammatory responses that result in massive transepithelial migration of neutrophils across the intestinal mucosa. it has previously been shown with salmonella enterica serotype typhimurium that the process of neutrophil transmigration is mediat ...200818505810
the serine protease motif of pic mediates a dose-dependent mucolytic activity after binding to sugar constituents of the mucin substrate.the pic gene is harbored on the chromosomes of three important pathogens: enteroaggregative escherichia coli (eaec), uropathogenic e. coli (upec), and shigella flexneri. since pic is secreted into the intestinal lumen during eaec infection, we sought to identify intestinal-mucosal substrates for pic. pic did not damage epithelial cells, cleave fodrin, or degrade host defense proteins embedded in the mucus layer (siga, lactoferrin and lysozyme). however, by using a solid-phase assay to evaluate t ...200818538533
shigella bacteraemia over a decade in soweto, south africa.shigella infection rarely penetrates beyond the intestinal mucosa to cause bacteraemia. aids patients may be at increased risk. we investigated shigella bacteraemia rates over a decade in a south african population with a high hiv prevalence and analysed presentation and outcome. a retrospective cohort analysis was performed for hospitalized patients for 2003-2006. the rates were compared to those for 1996-1998. adult medical rates decreased from 0.195/1000 in 1996-1998 to 0.087/1000 admissions ...200818550134
molecular characterization of multidrug-resistant shigella species isolated from epidemic and endemic cases of shigellosis in india.shigella species represent one of the growing numbers of antimicrobial-resistant bacteria in developing countries. fluoroquinolone-resistant strains of shigella dysenteriae type 1 and shigella flexneri type 2a emerged in india during 2002 and 2003, respectively. sixty strains of shigella from different parts of india were analysed for antimicrobial susceptibility, the presence of the qnr plasmid, mutations in the quinolone resistance determining regions (qrdrs), fluoroquinolone accumulation, and ...200818566144
design, synthesis, characterization, antibacterial and antifungal activities of a novel class of 5,7-diaryl-4,4-dimethyl-4,5,6,7-tetrahydropyridino[3,4-d]-1,2,3-selenadiazoles.compound 26 is more potent against escherichia coli. and 24 is more active against staphylococcus aureus, beta-heamolytic streptococcus, vibreo cholerae, salmonella typhii, and shigella flexneri than the standard drug ciprofloxacin. moreover, of all the compounds tested, 26 is more effective against aspergillus flavus and mucor, than the standard drug fluconazole.200818569338
vibrio cholerae vcib promotes iron uptake via ferrous iron transporters.vibrio cholerae uses a variety of strategies for obtaining iron in its diverse environments. in this study we report the identification of a novel iron utilization protein in v. cholerae, vcib. the vcib gene and its linked gene, vcia, were isolated in a screen for v. cholerae genes that permitted growth of an escherichia coli siderophore mutant in low-iron medium. the vciab operon encodes a predicted tonb-dependent outer membrane receptor, vcia, and a putative inner membrane protein, vcib. vcib, ...200818586940
anti-infectious effect of s-benzylisothiourea compound a22, which inhibits the actin-like protein, mreb, in shigella flexneri.s-benzylisothiourea compound a22 induces coccoid forms in escherichia coli by inhibiting the function of the actin-like cytoskeletal protein, mreb. the minimum inhibitory concentration of a22 and the minimum concentration to induce coccoid forms for various pathogenic bacteria were determined. at 10 microg/ml, a22 induced coccoid forms in shigella flexneri but did not inhibit the growth. no alteration of coccoid forms in the gram-positive bacteria and anaerobic bacteria tested were observed foll ...200818591769
[epidemic strains of different plasmidovars of bacteria from shigella genus].plasmid analysis of 46 strains of shigella species confirmed the view about heterogeneity and variability of plasmids composition in these microorganisms. on the other hand,the presence of low-molecular, multiplicated extrachromosomal replicons, which were stable, was shown. using them, it was possible to divide the shigella isolates into two major plasmidovars, characterize them according to repertoire of the most stable plasmids and determine epidemically significant variants during sporadic a ...200818595459
[electrical resistance of bacterial culture suspension as indicator of epidemic and sporadic variants of shigella].for the first time method of measurement of electric resistance of bacterial suspension was used for differentiation of "epidemic" and "sporadic" (further used without quotes) variants of shigella species. study of 40 strains of s. flexneri and s. sonnei revealed significant differences in electric resistance of cultures isolated during epidemic outbreaks after the growth during 1 or 6 hours - 18.1+/-8.3 kohm and 84.6+/-7.8 kohm respectively (increase in 4.9-fold; p<0.01), while non significant ...200818597992
shigella isolates of nepal: changes in the incidence of shigella subgroups and trends of antimicrobial susceptibility pattern.shigellosis is an important cause of bloody diarrhoea in all age groups, especially in children. a retrospective study was done to analyse the pattern of shigella isolates and the antimicrobial susceptibility trend of these shigella isolated at different hospitals of nepal from jan, 2003- dec, 2005.200718603983
intracellular bacteriolysis triggers a massive apoptotic cell death in shigella-infected epithelial cells.infected epithelial cells, which act as a first barrier against pathogens, seldom undergo apoptosis. rather, infected epithelial cells undergo a slow cell death that displays hallmarks of necrosis. here, we demonstrate that rapid intracellular lysis of shigella flexneri, provoked by either the use of a diaminopimelic acid auxotroph mutant or treatment of infected cells with antibiotics of the beta-lactam family, resulted in a massive and rapid induction of apoptotic cell death. this intracellula ...200818606244
selective activation of human intestinal mast cells by escherichia coli hemolysin.mast cells (mcs) are recognized to play an important role in bacterial host defense in the murine system. in this study, we studied the interaction of human mcs, isolated from the intestine and purified to homogeneity, with different escherichia coli and shigella flexneri strains. we show that alpha-hemolysin (hly)-producing e. coli strains induce the release of histamine, leukotrienes, and proinflammatory cytokines in intestinal mcs. in contrast, mcs were virtually unresponsive to s. flexneri a ...200818606698
lomefloxacin versus trimethoprim/sulfamethoxazole in the treatment of adults with acute bacterial diarrhea.this study compared the efficacy and safety of lomefloxacin with that of trimethoprim/sulfamethoxazole (tmp/smx) in the treatment of adult patients with acute diarrhea of bacterial etiology. two centers enrolled a total of 133 patients; 99 (74%) presented with severe symptoms. the patients were randomized to receive either lomefloxacin 400 mg once daily (n=68) or tmp/smx 160/800 mg twice daily (n=65) for five days. bacteriologic success was achieved in 89.5% of evaluation lomefloxacin-treated pa ...199218611521
structures of synthetic o-antigen fragments from serotype 2a shigella flexneri in complex with a protective monoclonal antibody.the anti-lps igg mab f22-4, raised against shigella flexneri serotype 2a bacteria, protects against homologous, but not heterologous, challenge in an experimental animal model. we report the crystal structures of complexes formed between fab f22-4 and two synthetic oligosaccharides, a decasaccharide and a pentadecasaccharide that were previously shown to be both immunogenic and antigenic mimics of the s. flexneri serotype 2a o-antigen. f22-4 binds to an epitope contained within two consecutive 2 ...200818621718
crystal structure of a glutamate/aspartate binding protein complexed with a glutamate molecule: structural basis of ligand specificity at atomic resolution.the crystal structure of a periplasmic l-aspartate/l-glutamate binding protein (debp) from shigella flexneri complexed with an l-glutamate molecule has been determined and refined to an atomic resolution of 1.0 a. there are two debp molecules in the asymmetric unit. the refined model contains 4462 non-hydrogen protein atoms, 730 water molecules, 2 bound glutamate molecules, and 2 tris molecules from the buffer used in crystallization. the final r(cryst) and r(free) factors are 13.61% and 16.89%, ...200818640128
acute diarrhea due to enteropathogenic bacteria in patients at hospitals in tehran.during a study examining causes of diarrhea from may 2004 to may 2005, 808 stool specimens were collected from patients with acute diarrhea in tehran. fecal samples were cultured and identified according to the standard biochemical methods. molecular identification of enteropathogens was carried out by amplification of their virulence genes by polymerase chain reaction. a total of 369 (45.6%) bacterial pathogens were recovered from 808 patients as follows: shigella spp., 155 (45.6%); diarrheagen ...200818653967
antimicrobial resistance in shigella species isolated in dakar, senegal (2004-2006).from may 2004 to october 2006, a prospective study was carried out in dakar, senegal, to update information about the antimicrobial susceptibility of shigella spp. isolated from stool specimens. among the 165 non-duplicate strains collected, 81 (49%) were identified as shigella flexneri, 75 (45%) as shigella sonnei, 5 (3%) as shigella boydii, and 4 (2%) as shigella dysenteriae. disk diffusion testing revealed that the majority of isolates were resistant to sulphonamides, trimethoprim-sulfamethox ...200818653976
the c-terminus of ipac is required for effector activities related to shigella invasion of host cells.invasion plasmid antigen c (ipac) is secreted by the shigella flexneri type iii secretion system (ttss) as an essential trigger of epithelial cell invasion. at the molecular level, ipac possesses a distinct functional organization. the ipac c-terminal region between amino acids 319 and 345 is predicted to form a coiled-coil structure. such alpha-helical motifs appear to be a recurring structural theme among ttss components. together with ipab, this ipac region is also required for the formation ...200818656530
characterization of soluble complexes of the shigella flexneri type iii secretion system atpase.the conserved atpase of type iii secretion systems is critical to the export of substrates through the apparatus. we present a characterization of the native t3ss atpase, spa47, from the cytoplasm of shigella flexneri, demonstrating it to be in two distinct high-molecular-weight complexes with spa33: mxin and mxik.200818657109
use of mchi encoding immunity to the antimicrobial peptide microcin h47 as a plasmid selection marker in attenuated bacterial live vectors.live attenuated bacterial strains expressing heterologous antigens represent an attractive vaccine development strategy. however, the use of drug resistance genes for the selection of expression plasmids introduced into live vectors poses theoretical health risks. therefore, we developed a novel approach for plasmid selection based on immunity to the antimicrobial peptide microcin h47 (mcch47). two expression plasmids encoding the reporter green fluorescent protein (gfpuv) were constructed; sele ...200818663003
bacterial biosensors for rapid and effective monitoring of biodegradation of organic pollutants in wastewater effluents.significant amounts of toxic substances which are hazardous to animals, plants, microorganisms, and other living organisms including humans are released annually into aquatic and terrestrial environments, mostly from improper wastewater discharges. early detection of such pollutants in wastewater effluents and proper monitoring before their final release into the environment is therefore necessary. in this study, two whole-cell bacterial biosensors were constructed by transforming competent cell ...200818688458
epidemiology of highly endemic multiply antibiotic-resistant shigellosis in children in the peruvian amazon.our goal was to estimate the impact of a shigella vaccine in an area where shigellosis is endemic by characterizing the disease burden and antibiotic-resistance profiles of isolates and by determining the prevalence of shigella flexneri serotypes.200818710884
resistance to fluoroquinolones by the combination of target site mutations and enhanced expression of genes for efflux pumps in shigella flexneri and shigella sonnei strains isolated in korea.among 5938 clinical shigella spp. isolates, two s. flexneri strains were isolated as those resistant to fluoroquinolones based on the mics of the following antibiotics: ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin and levofloxacin. s. flexneri 021787 had three substitutions, one in gyra (ser83leu) and two in parc (ser80ile and arg91gln). s. flexneri 021895 had four substitutions, two in gyra (ser83leu and asp87gly) and two in parc (ser80ile and arg91gln). the increased susceptibility of s ...200818727800
the relationship between genetics and environment in the pathogenesis of rheumatic diseases.major developments have taken place to further our understanding of the relationship between genetics and the environment in the pathogenesis of rheumatic disorders. the association between hla markers and human disease is becoming clearer. for instance, hla-drw4 frequently occurs in patients with rheumatoid disease, and penicillamine and gold toxicity are seen most often in patients with hla-drw2 or drw3. antisera to b alloantigens help define the genetic differences between systemic lupus eryt ...197918748470
occurrence and characteristics of the cytolysin a gene in shigella strains and other members of the family enterobacteriaceae.cytolysin a (clya, hlye, shea) is a hemolytic pore-forming toxin found in escherichia coli and salmonella enterica serovars typhi and paratyphi a. in the present study, analysis of several shigella strains revealed that they harbor only nonfunctional clya gene copies that have been inactivated either by the integration of insertion sequence (is) elements (shigella dysenteriae, shigella boydii, and shigella sonnei strains) or by a frameshift mutation (shigella flexneri). shigella dysenteriae and ...200818754791
topology and identification of critical residues of the o-acetyltransferase of serotype-converting bacteriophage, sf6, of shigella flexneri.the modification of the lps o-antigen, seen in the diverse serotypes of shigella flexneri is brought about by the glucosyltransferases (gtr) and the o-acetyltransferase (oac). in this study, we establish the membrane topology of oac using the dual reporter phoa-laczalpha. we have determined that oac is an integral membrane protein with 10 transmembrane regions. the hydrophilic n- and c-termini are oriented in the cytoplasm. functionally important cytoplasmic and periplasmic loops have also been ...200818755141
construction of a trivalent candidate vaccine against shigella species with dna recombination.in this work asd gene of shigella flexneri 2a strain t32 was replaced by vibrio cholerae toxin b subunit (ctxb) gene with dna recombination in vivo and in vitro. the resulting derivative of t32, designed as fwl01, could stably express ctxb, but its growth in lb medium depended on the presence of diaminopimelic acid (dap). then form i plasmid of shigella sonnei strain s7 was labeled with strain t32 asd gene and mobilized into fwl01. thus a trivalent candidate oral vaccine strain, designed as fsw0 ...200218763059
structural and functional studies indicate that shigella vira is not a protease and does not directly destabilize microtubules.vira, an essential virulence factor in shigella disease pathogenesis, is involved in the uptake, motility, and cell-to-cell spread of shigella organisms within the human host. these functions have been attributed to a vira protease activity and a mechanism of microtubule destruction via tubulin degradation [yoshida, s., et al. (2006) science 314, 985-989]. we report functional and crystallographic data indicating a novel vira structure that lacks these activities but highlights the homology to t ...200818763811
bacterial conjugation in the cytoplasm of mouse cells.intracellular pathogenic organisms such as salmonellae and shigellae are able to evade the effects of many antibiotics because the drugs are not able to penetrate the plasma membrane. in addition, these bacteria may be able to transfer genes within cells while protected from the action of drugs. the primary mode by which virulence and antibiotic resistance genes are spread is bacterial conjugation. salmonellae have been shown to be competent for conjugation in the vacuoles of cultured mammalian ...200818765719
rapid allelic exchange in enterohemorrhagic escherichia coli (ehec) and other e. coli using lambda red recombination.this unit describes an allelic exchange system for enterohemorrhagic e. coli (ehec), and similar pathogenic species of bacteria. the phage lambda red recombination system is expressed from a plasmid, inducing a hyper-recombinogenic state where electroporated pcr-generated substrates recombine with the bacterial chromosome at high efficiency. the technique can be used to substitute a drug marker for the gene of interest, or used to generate a clean in-frame deletion of the target gene. single gen ...200618770591
novel fold of vira, a type iii secretion system effector protein from shigella flexneri.vira, a secreted effector protein from shigella sp., has been shown to be necessary for its virulence. it was also reported that vira might be related to papain-like cysteine proteases and cleave alpha-tubulin, thus facilitating intracellular spreading. we have now determined the crystal structure of vira at 3.0 a resolution. the shape of the molecule resembles the letter "v," with the residues in the n-terminal third of the 45-kda molecule (some of which are disordered) forming one clearly iden ...200818787201
incidence of bacterial enteropathogens among hospitalized diarrhea patients from orissa, india.bacteriological analysis of 1,551 stool/rectal swabs from all age groups of diarrhea patients of different hospitals of orissa from january 2004 to december 2006 was carried out using standard procedures. among all enteropathogens isolated in 886 culture-positive samples, escherichia coli constituted 75.5%, including 13.2% pathogenic e. coli; vibrio cholerae o1 constituted 17.3%; v. cholerae o139, 1%; shigella spp., 4.5% (shigella flexneri type 6, 2.9%, s. dysenteriae type i, 0.7%, s. sonnei, 0. ...200818806340
subproteomic tools to increase genome annotation complexity.comprehensive and precise annotations of short protein-coding genes are always a challenging task. here we propose a new design to facilitate the characterization of previously overlooked short protein-coding genes by integrating a shotgun proteomics method and oligonucleotide array analysis. using shigella flexneri as a model, we validate 163 annotated orfs and 51 hypothetical or putative transcripts at the protein level, and discover four novel short orfs. this strategy will contribute signifi ...200818814329
nlrc4/ipaf: a card carrying member of the nlr family.the nod-like receptor (nlr) family of proteins is involved in the regulation of innate immune responses and cell death pathways. recent findings show that the nlr family member nlrc4 (also known as ipaf) has important roles in innate immune responses to gram-negative bacteria. macrophages infected with legionella pneumophila, salmonella typhimurium, shigella flexneri, or pseudomonas aeruginosa activate caspase-1 in an nlrc4-dependent manner leading to macrophage cell death and the release of pro ...200918819842
metal based isatin-derived sulfonamides: their synthesis, characterization, coordination behavior and biological activity.some isatin derived sulfonamides and their transition metal [co(ii), cu(ii), ni(ii), zn(ii)] complexes have been synthesized and characterized. the structure of synthesized compounds and their nature of bonding have been inferred on the basis of their physical (magnetic susceptibility and conductivity measurements), analytical (elemental analyses) and spectral (ir, (1)h nmr and (13)c nmr) properties. an octahedral geometry has been suggested for co(ii), ni(ii) and zn(ii) and square-planar for cu ...200918825557
evaluation by real-time pcr of the expression of s. flexneri virulence-associated genes ospb and phon2 under different genetical backgrounds.under conditions of activated type iii secretion shigella flexneri up-regulates the expression of numerous genes, including the virulence plasmid (pinv)-encoded ospb and phon2 genes. ospb and phon2 are virulence-associated genes which are part of a bicistronic transcriptional unit encoding ospb, a protein (effector) of unknown function secreted by the type iii secretion (tts) apparatus, and phon2 (apyrase or atp-diphosphohydrolase), a periplasmic protein involved in polar icsa localization on th ...200818831939
reduction in infection risk through treatment of microbially contaminated surfaces with a novel, portable, saturated steam vapor disinfection system.surface-mediated infectious disease transmission is a major concern in various settings, including schools, hospitals, and food-processing facilities. chemical disinfectants are frequently used to reduce contamination, but many pose significant risks to humans, surfaces, and the environment, and all must be properly applied in strict accordance with label instructions to be effective. this study set out to determine the capability of a novel chemical-free, saturated steam vapor disinfection syst ...200918834748
[htpg protein of shigella flexneri 2a strain 2457t evokes inflammatory response in mice].to analyze the function of htpg of s. flexneri 2a 2457t, we constructed an htpg deletion mutant and a recovery mutant.200818837368
prevalence and antibiotic resistant shigellae among primary school children in urban calabar, nigeria.in a recent study, involving the examination of 593 stool samples obtained from randomly selected children from three primary schools in calabar, shigella spp. were isolated from 123 (20.7%) of the samples. the infection rate was highest among the younger children with (64.2%) 79/123 of the isolates coming from children under 10 years of age. infection rate was comparable among boys and girls (p = 0.1). only two species of shigella were isolated viz: shigella flexneri 12.0% (71/593) and shigella ...200418839866
[analysis on incidence of bacillary dysentery in jinan municipality from 1951 to 2005].to explore the epidemic characteristics of bacterial dysentery in jinan municipality, and to provide scientific basis for effective strategy for bacterial dysentery control.200818844085
invasion by shigella sonnei of tissues of mice following gavage with viable shigella. 194818863683
prolonged laboratory observations on clinical cases and carriers of shigella flexneri iii following an epidemic. 194818864928
responses of human subjects to vaccines in saline-in-mineral oil emulsion; shigella paradysenteriae vaccines. 194818897990
[not available]. 194818911146
an outbreak of shigella flexneri infection among rheus monkeys. 194818915380
experimental type transformation of shigella paradysenteriae (flexner). 194718921755
in this issue: proteomics 20/2008.in this issue of proteomics you will find the following highlighted articles:comprehensively confirmed annotation of short orfsduring the california gold rush, prospectors did not look only for large nuggets to pave their road to riches - they also collected gold dust. the proteomic equivalent of dust is the small orf. it does not pay to put a lower limit on dust or orf size because almost any size may be turned into "cash" or an important peptide. wei et al. demonstrate how a combination of con ...200818924177
a pilot sheds light on secretin assembly. 200818940600
structural characterization of the type-iii pilot-secretin complex from shigella flexneri.assembly of the type-iii secretion apparatus, which translocates proteins through both membranes of gram-negative bacterial pathogens into host cells, requires the formation of an integral outer-membrane secretin ring. typically, a small lipidated pilot protein is necessary for the stabilization and localization of this ring. using nmr spectroscopy, we demonstrate that the c-terminal residues 553-570 of the shigella flexneri secretin mxid encompass the minimal binding domain for its cognate pilo ...200818940609
detection of protozoan and bacterial pathogens of public health importance in faeces of corvus spp. (large-billed crow).parasites and bacteria are reported in the faeces of birds in the current study. fresh faecal samples of the large-billed crow (corvus spp.) were collected from the study site at bangsar, an urban setting in kuala lumpur, malaysia. these samples were transported to laboratory and analysed for parasites and bacteria. pre-prepared xld agar plates were used for culturing the bacteria in the laboratory. using the api 20etm test strips, 9 different species of bacteria were identified belonging to the ...200818948884
analysis of immune responses and serological cross reactivities among vibrio cholerae o1, shigella flexneri 2a and haemophilus influenzae b.antigenic determinants expressed on the bacterial cell surface are of importance in the serological characterization and microbiological diagnosis. the bacterial strains carrying these identical or similar antigenic epitopes might react with antibodies produced against other strains. in this study, strong immunogenicity and antigenic cross reactivity were demonstrated among v. cholerae o1, s. flexnerii 2a and h. influenzae b surface components. the enzyme linked immunosorbent assay (elisa) resul ...200818954564
small-molecule type iii secretion system inhibitors block assembly of the shigella type iii secreton.type iii secretion systems (t3sss) are essential virulence devices for many gram-negative bacteria that are pathogenic for plants, animals, and humans. they serve to translocate virulence effector proteins directly into eukaryotic host cells. t3sss are composed of a large cytoplasmic bulb and a transmembrane region into which a needle is embedded, protruding above the bacterial surface. the emerging antibiotic resistance of bacterial pathogens urges the development of novel strategies to fight b ...200918996990
structure of the shigella t3ss effector ipah defines a new class of e3 ubiquitin ligases.ipah proteins are e3 ubiquitin ligases delivered by the type iii secretion apparatus into host cells upon infection of humans by the gram-negative pathogen shigella flexneri. these proteins comprise a variable leucine-rich repeat-containing n-terminal domain and a conserved c-terminal domain harboring an invariant cysteine residue that is crucial for activity. ipah homologs are encoded by diverse animal and plant pathogens. here we demonstrate that the ipah c-terminal domain carries the catalyti ...200818997778
structure of a shigella effector reveals a new class of ubiquitin ligases.bacterial pathogens have evolved effector proteins with ubiquitin e3 ligase activities through structural mimicking. here we report the crystal structure of the shigella flexneri type iii effector ipah3, a member of the leucine-rich repeat (lrr)-containing bacterial e3 family. the lrr domain is structurally similar to yersinia pestis yopm and potentially binds to substrates. the structure of the c-terminal e3 domain differs from the typical ring- and hect-type e3s. ipah3 synthesizes a lys48-link ...200818997779
tlr4 and myd88 control protection and pulmonary granulocytic recruitment in a murine intranasal rsv immunization and challenge model.an intranasal vaccine composed of toll-like receptor 2 (tlr2) ligand neisseria meningitidis outer membrane proteins and toll-like receptor 4 (tlr4) ligand shigella flexneri lipopolysaccharide (lps) (protollin) and enriched respiratory syncytial virus (rsv) proteins (ersv) has been demonstrated to promote balanced th1/th2 responses without eosinophil recruitment and to protect against challenge in mouse models. we used tlr2, tlr4 and myeloid differentiation factor 88 (myd88) knock-out (-/-) mice ...200919013492
mxic is secreted by and controls the substrate specificity of the shigella flexneri type iii secretion apparatus.many gram-negative pathogenic bacteria use a type iii secretion (t3s) system to interact with cells of their hosts. mechanisms controlling the hierarchical addressing of needle subunits, translocators and effectors to the t3s apparatus (t3sa) are still poorly understood. we investigated the function of mxic, the member of the yopn/inve/sepl family in the shigella flexneri t3s system. inactivation of mxic led specifically to a deregulated secretion of effectors (including ipaa, ipgd, icsb, ipgb2, ...200919017268
shigella flexneri type iii secretion system effectors ospb and ospf target the nucleus to downregulate the host inflammatory response via interactions with retinoblastoma protein.ospf, ospg and ipah(9.8) are type iii secretion system (t3ss) effectors of shigella flexneri that downregulate the host innate immune response. ospf modifies mitogen-activated protein kinase pathways and polymorphonuclear leucocyte transepithelial migration associated with shigella invasion. ospf also localizes in the nucleus to mediate chromatin remodelling, resulting in reduced transcription of inflammatory cytokines. we now report that ospb can be added to the set of s. flexneri t3ss effector ...200919017275
spa32 interaction with the inner-membrane spa40 component of the type iii secretion system of shigella flexneri is required for the control of the needle length by a molecular tape measure mechanism.the effectors of enterocyte invasion by shigella are dependent on a type iii secretion system that contains a needle whose length average does not exceed 50 nm. previously, we reported that spa32 is required for needle length control as well as to switch substrate specificity from mxih to ipa proteins secretion. to identify functional domains of spa32, 11 truncated variants were constructed and analysed for their capacity (i) to control the needle's length; (ii) to secrete the ipa proteins; and ...200819019157
antigen-specific b memory cell responses to lipopolysaccharide (lps) and invasion plasmid antigen (ipa) b elicited in volunteers vaccinated with live-attenuated shigella flexneri 2a vaccine candidates.we evaluated b memory responses in healthy adult volunteers who received one oral dose of live-attenuated shigella flexneri 2a vaccine. lps-specific b(m) cells increased from a median of 0 at baseline to 20 spot forming cells (sfc)/10(6) expanded cells following vaccination (p=0.008). a strong correlation was found between post-vaccination anti-lps b(m) cell counts and peak serum anti-lps igg titers (rs=0.95, p=0.0003). increases in b(m) specific for ipab approaching significance were also obser ...200919022324
interaction of enteric bacterial pathogens with murine embryonic stem cells.embryonic stem (es) cells are susceptible to genetic manipulation and retain the potential to differentiate into diverse cell types, which are factors that make them potentially attractive cells for studying host-pathogen interactions. murine es cells were found to be susceptible to invasion by salmonella enterica serovar typhimurium and shigella flexneri and to the formation of attaching and effacing lesions by enteropathogenic escherichia coli. s. enterica serovar typhimurium and s. flexneri c ...200919029302
the acrab-tolc pump is involved in multidrug resistance in clinical shigella flexneri isolates.the two multiple-antibiotic resistance (mar) phenotypes (n = 8, respectively) and susceptible isolates (n = 4) of shigella flexneri from china were characterized involving the efflux pump acrab-tolc. the accumulation of ciprofloxacin, acrab-tolc pcr, and levels of mrna with northern blots were performed in three groups. sequencing of acrab-tolc was performed in selected isolates. an efflux inhibition was performed with phe-arg-beta-naphthylamide. the accumulation of ciprofloxacin at steady state ...200819035770
gef-h1 mediated control of nod1 dependent nf-kappab activation by shigella effectors.shigella flexneri has evolved the ability to modify host cell function with intracellular active effectors to overcome the intestinal barrier. the detection of these microbial effectors and the initiation of innate immune responses are critical for rapid mucosal defense activation. the guanine nucleotide exchange factor h1 (gef-h1) mediates rhoa activation required for cell invasion by the enteroinvasive pathogen shigella flexneri. surprisingly, gef-h1 is requisite for nf-kappab activation in re ...200819043560
contribution of the periplasmic chaperone skp to efficient presentation of the autotransporter icsa on the surface of shigella flexneri.icsa is an outer membrane protein in the autotransporter family that is required for shigella flexneri pathogenesis. following its secretion through the sec translocon, icsa is incorporated into the outer membrane in a process that depends on yaet, a component of an outer membrane beta-barrel insertion machinery. we investigated the role of the periplasmic chaperone skp in icsa maturation. skp is required for the presentation of the mature amino terminus (alpha-domain) of icsa on the bacterial s ...200919047350
characterization of shigella spp. by antimicrobial resistance and pcr detection of ipa genes in an infantile population from porto velho (western amazon region), brazil.the incidence of shigella spp. was assessed in 877 infants from the public hospital in rondônia (western amazon region, brazil) where shigella represents the fourth cause of diarrhea. twenty-five isolates were identified: 18 were shigella flexneri, three shigella sonnei, three shigella boydii and one shigella dysenteriae. with the exception of s. dysenteriae, all shigella spp. isolated from children with diarrhea acquired multiple antibiotic resistances. pcr detection of ipa virulence genes and ...200819057826
tight junctions as targets of infectious agents.the epithelial barrier is a critical border that segregates luminal material from entering tissues. essential components of this epithelial fence are physical intercellular structures termed tight junctions. these junctions use a variety of transmembrane proteins coupled with cytoplasmic adaptors, and the actin cytoskeleton, to attach adjacent cells together thereby forming intercellular seals. breaching of this barrier has profound effects on human health and disease, as barrier deficiencies ha ...200919059200
prevalence of sulfonamide resistance genes in bacterial isolates from manured agricultural soils and pig slurry in the united kingdom.the prevalences of three sulfonamide resistance genes, sul1, sul2, and sul3 and sulfachloropyridazine (scp) resistance were determined in bacteria isolated from manured agricultural clay soils and slurry samples in the united kingdom over a 2-year period. slurry from tylosin-fed pigs amended with scp and oxytetracycline was used for manuring. isolates positive for sul genes were further screened for the presence of class 1 and 2 integrons. phenotypic resistance to scp was significantly higher in ...200919064898
increased isolation and characterization of shigella sonnei obtained from hospitalized children in tehran, iran.shigella flexneri has been the most frequent cause of shigellosis in children in iran. to evaluate the changes in frequency of serogroups, 302 shigella species were isolated in 2003 from hospitalized children, aged less than 12 years, with acute diarrhoea in tehran, iran. the number of collected s. sonnei, s. flexneri, s. boydii, and s. dysenteriae isolates was 178 (58.9%), 110 (37.4%), 10 (3.3%), and 4 (1.3%) respectively. most (94%) s. sonnei isolates were resistant to co-trimoxazole. they wer ...200819069621
molecular detection of all 34 distinct o-antigen forms of shigella.shigella is the cause of shigellosis or bacillary dysentery, the occurrence of which is estimated to be 165 million cases per year worldwide, resulting in 1.1 million deaths. rapid and reliable assays for detecting and identifying shigella in food, environmental and clinical samples are therefore necessary. shigella species are traditionally identified by their o antigens. this study developed a dna microarray targeting o-serotype-specific genes to detect all 34 distinct o-antigen forms of shige ...200919074655
shigella from humans in thailand during 1993 to 2006: spatial-time trends in species and serotype distribution.in thailand during 1993-2006, a total of 9063 shigella isolates from different medical centers were serotyped and trends over time and spatial clustering analyzed. of 3583 cases with age information, 1315 (37%) cases were from children between 0 and 4 years and 684 (19%) from children between 5 and 8 years. most infections were recorded during 1993-1994 (> 1500 per year), decreasing to < 200 in 2006. the relative species distribution also changed. during 1993-1994, shigella flexneri accounted fo ...200819086804
fungal and bacterial killing by neutrophils.neutrophils are professional phagocytes of the innate immune system that are essential to control bacterial and fungal infections. these cells engulf and kill invading microbes. additionally, activated neutrophils are able to release neutrophil extracellular traps (nets). these fibers consist of chromatin decorated with antimicrobial proteins to trap and kill microbes. appropriate quantitative methods are required to understand the nature of interactions of neutrophils with pathogens. here we pr ...200919089391
extensive antibody cross-reactivity among infectious gram-negative bacteria revealed by proteome microarray analysis.antibodies provide a sensitive indicator of proteins displayed by bacteria during sepsis. because signals produced by infection are naturally amplified during the antibody response, host immunity can be used to identify biomarkers for proteins that are present at levels currently below detectable limits. we developed a microarray comprising approximately 70% of the 4066 proteins contained within the yersinia pestis proteome to identify antibody biomarkers distinguishing plague from infections ca ...200919112181
diagnosis and prevalence of enteropathogenic bacteria in children less than 5 years of age with acute diarrhea in tehran children's hospitals.acute diarrhea disease is the second cause of death among all infectious diseases in children younger than 5 years of age worldwide. the aim of this study was to employ a combination of biochemical, microbiological and molecular diagnostic techniques to investigate the stools of iranian children with acute diarrhea for bacterial enteropathogens.200919117609
genetics and environmental regulation of shigella iron transport systems.shigella spp. have transport systems for both ferric and ferrous iron. the iron can be taken up as free iron or complexed to a variety of carriers. all shigella species have both the feo and sit systems for acquisition of ferrous iron, and all have at least one siderophore-mediated system for transport of ferric iron. several of the transport systems, including sit, iuc/iuta (aerobactin synthesis and transport), fec (ferric di-citrate uptake), and shu (heme transport) are encoded within pathogen ...200919130265
frequency of isolation of various subtypes and antimicrobial resistance of shigella from urban slums of karachi, pakistan.shigellosis remains a major public health problem in developing countries. antimicrobial resistance has complicated the empirical treatment. knowledge of serotypes is crucial in vaccine development, as cross-protection between various serotypes is limited. therefore we conducted a prospective study to determine the frequency of isolation of shigella serotypes and antimicrobial resistance.200919135399
in silico comparison of simple sequence repeats in high nucleotides-rich genomes of microorganism.this study determined the distribution of a specific group of simple sequence repeats (ssrs), in genome sequences of 7 chromosomes (shigella flexneri 2a str 301 and 2457 t, shigella sonnei, e. coli k12, m. tuberculosis, m. leprae and s. saprophytycus) have downloaded from the genbank database for identifying abundance, distribution and composition of ssrs. the data obtained in the present study show that: (i) tandem repeats are widely distributed throughout the genomes. (ii) ssrs are differentia ...200819137845
overexpression, purification, characterization and preliminary crystallographic study of phosphoglycolate phosphatase from shigella flexneri 2a strain 301.phosphoglycolate phosphatase has a salvage function in the metabolism of the 2-phosphoglycolate formed during bacterial dna repair. in order to better understand its dimerization behaviour, the influence of metal ions on its activity and its catalytic mechanism at the molecular level, recombinant phosphoglycolate phosphatase from shigella flexneri was overexpressed, purified, characterized and crystallized by the hanging-drop vapour-diffusion method at 291 k using polyethylene glycol 3500 as a p ...200919153451
simultaneous detection of multifood-borne pathogenic bacteria based on functionalized quantum dots coupled with immunomagnetic separation in food samples.this paper reports a method that simultaneously detects three food-borne pathogenic bacteria, salmonella typhimurium, shigella flexneri, and escherichia coli o157:h7, via an approach that combines magnetic microparticles for the enrichment and antibody-conjugated semiconductor quantum dots (qds) as fluorescence markers. using the water-in-oil reverse microemulsions method, the gamma-fe(2)o(3) magnetic nanoparticles were coated with silica to empower the particles with high dispersibility and bro ...200919154162
the ipac carboxyterminal effector domain mediates src-dependent actin polymerization during shigella invasion of epithelial cells.shigella, the causative agent of bacillary dysentery, invades epithelial cells by locally reorganizing the actin cytoskeleton. shigella invasion requires actin polymerization dependent on the src tyrosine kinase and a functional bacterial type iii secretion (t3s) apparatus. using dynamic as well as immunofluorescence microscopy, we show that the t3s translocon component ipac allows the recruitment of the src kinase required for actin polymerization at bacterial entry sites during the initial sta ...200919165331
short report: high prevalence of serine protease autotransporter cytotoxins among strains of enteroaggregative escherichia coli.enteroaggregative escherichia coli (eaec) pathogenesis is thought to comprise intestinal colonization followed by the release of enterotoxins and cytotoxins. here, we use a polymerase chain reaction (pcr) to determine the prevalence of 10 genes encoding serine protease autotransporter toxins (spates) in a collection of clinical eaec isolates. eighty-six percent of eaec strains harbored genes encoding one or more class i cytotoxic spate proteins (pet, sat, espp, or siga). two class ii, non-cytoto ...200919190229
crystal structure analysis and in silico pka calculations suggest strong pka shifts of ligands as driving force for high-affinity binding to tgt.a novel ligand series is presented to inhibit trna-guanine transglycosylase (tgt), a protein with a significant role in the pathogenicity mechanism of shigella flexneri, the causative agent of shigellosis. the enzyme exchanges guanine in the wobble position of trna(asn,asp,his,tyr) against a modified base. to prevent the base-exchange reaction, several series of inhibitors have already been designed, synthesized, and tested. one aim of previous studies was to address a hydrophobic pocket with di ...200919199329
streptococcus-, shigella-, and listeria-induced autophagy.autophagy has recently been described as an intrinsic host defense system for recognizing and eliminating intracellular-invading bacterial pathogens. some cytoplasmic-invading bacteria are trapped through the process of autophagy and are ultimately degraded within autolysosomal compartments. however, others exhibit highly evolved maneuvers for circumventing autophagic recognition and are capable of surviving and replicating within the cytoplasm. in this chapter, we describe bacterial infectious ...200919200893
a synthetic carbohydrate-protein conjugate vaccine candidate against shigella flexneri 2a infection.the protective ag of shigella, the gram-negative enteroinvasive bacterium causing bacillary dysentery, or shigellosis, is its o-specific polysaccharide (o-sp) domain of the lps, the major bacterial surface component. as an alternative to the development of detoxified lps-based conjugate vaccines, recent effort was put into the investigation of neoglycoproteins encompassing synthetic oligosaccharides mimicking the protective ags of the o-sp. we previously reported that when coupled to tetanus tox ...200919201878
pathogen trafficking pathways and host phosphoinositide metabolism.phosphoinositide (pi) glycerolipids are key regulators of eukaryotic signal transduction, cytoskeleton architecture and membrane dynamics. the host cell pi metabolism is targeted by intracellular bacterial pathogens, which evolved intricate strategies to modulate uptake processes and vesicle trafficking pathways. upon entering eukaryotic host cells, pathogenic bacteria replicate in distinct vacuoles or in the host cytoplasm. vacuolar pathogens manipulate pi levels to mimic or modify membranes of ...200919208094
the expression of lipopolysaccharide by strains of shigella dysenteriae, shigella flexneri and shigella boydii and their cross-reacting strains of escherichia coli.strains of shigella dysenteriae, shigella flexneri and shigella boydii express lipopolysaccharides, that enable the serotyping of strains based on their antigenic structures. certain strains of s. dysenteriae, s. flexneri and s. boydii are known to share epitopes with strains of escherichia coli; however, the lipopolysaccharide profiles of the cross-reacting organisms have not been compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page) lipopolysaccharides profiling. in ...200919222579
a similarity in the o-acetylation pattern of the o-antigens of shigellaflexneri types 1a, 1b, and 2a.shigella flexneri type 2a is the first, and type 1b is the second, most prevalent isolates from patients with shigellosis in russia. the o-specific polysaccharides (opss, o-antigens) of s. flexneri types 1-5 possess a common -->2)-alpha-l-rhapiii-(1-->2)-alpha-l-rhapii-(1-->3)-alpha-l-rhapi-(1-->3)-beta-d-glcpnac-(1--> backbone and differ from each other in its glucosylation or/and o-acetylation at various positions, the modifications being responsible for various o-factors. it was suggested tha ...200919246033
the mere protein encoded by transposon tn21 is a broad mercury transporter in escherichia coli.in order to clarify the physiological role of the mere gene of transposon tn21, a pe4 plasmid that contained the merr gene of plasmid pmr26 from pseudomonas strain k-62, and the mere gene of tn21 from the shigella flexneri plasmid nr1 (r100) was constructed. bacteria with plasmid pe4 (merr-o/p-mere) were more hypersensitive to ch(3)hg(i) and hg(ii), and took up significantly more ch(3)hg(i) and hg(ii), than the isogenic strain. the mere protein encoded by pe4 was localized in the membrane cell f ...200919265693
piscidin 4, a novel member of the piscidin family of antimicrobial peptides.piscidins are linear, amphipathic, antimicrobial peptides (amps) with broad, potent, activity spectrum. piscidins and other members of the piscidin family appear to comprise the most common group of amps in teleost fish. all piscidins and related members of the piscidin family described to date are 18-26 amino acids long.we report here the isolation of a novel 5329.25 da, 44-residue (ffrhlfrgakaifrgarqgxrahkvvsryrnrdvpetdnnqeep) antimicrobial peptide from hybrid striped bass (morone chrysops fem ...200919266617
high-let ion radiolysis of water: oxygen production in tracks.it is known that molecular oxygen is a product of the radiolysis of water with high-linear energy transfer (let) radiation, a result that is of particular significance in radiobiology and of practical relevance in radiotherapy. in fact, it has been suggested that the radiolytic formation of an oxygenated microenvironment around the tracks of high-let heavy ions is an important factor in their enhanced biological efficiency in the sense that this may be due to an "oxygen effect" by o(2) produced ...200919267566
the effects of the bacterial interaction with visible-light responsive titania photocatalyst on the bactericidal performance.bactericidal activity of traditional titanium dioxide (tio2) photocatalyst is effective only upon irradiation by ultraviolet light, which restricts the potential applications of tio2 for use in our living environments. recently carbon-containing tio2 was found to be photoactive at visible-light illumination that affords the potential to overcome this problem; although, the bactericidal activity of these photocatalysts is relatively lower than conventional disinfectants. evidenced from scanning e ...200919272171
characterisation of early mucosal and neuronal lesions following shigella flexneri infection in human colon.shigella, an enteroinvasive bacteria induces a major inflammatory response responsible for acute rectocolitis in humans. however, early effect of shigella flexneri (s. flexneri) infection upon the human mucosa and its microenvironement, in particular the enteric nervous system, remains currently unknown. therefore, in this study, we sought to characterize ex vivo the early events of shigellosis in a model of human colonic explants. in particular, we aimed at identifying factors produced by s. fl ...200919274103
efficient synthesis of six tri- to hexasaccharide fragments of shigella flexneri serotypes 3a and/or x o-antigen, including a study on acceptors containing n-trichloroacetylglucosamine versus n-acetylglucosamine.six tri- to hexasaccharide fragments of the {2)-[alpha-d-glcp-(1-->3)]-alpha-l-rhap-(1-->2)-alpha-l-rhap-(1-->3)-[ac-->2]-alpha-l-rhap-(1-->3)-beta-d-glcpnac-(1-->}(n) polymer ([(e)ab(ac)cd](n)) were synthesized as their propyl glycosides. all targets share the (e)ab sequence. following a thorough investigation on the use of n-trichloroacetylglucosamine- versus n-acetylglucosamine-containing tri- and tetrasaccharide acceptors, the successful strategy was based on an efficient combination of the ...200919278208
foodborne outbreaks, austria 2007.in 2007 austria reported a total of 438 foodborne outbreaks affecting 1715 people, including 286 hospitalized patients and one death. salmonella spp. and campylobacter spp. accounted for 95% of all reported outbreaks. forty-eight (11%) of the 438 austrian outbreaks were acquired abroad. of the 390 domestically acquired foodborne outbreaks, bacterial infection caused 376, viruses (norovirus and 1-time hepatitis a virus) caused 11, and intoxications (staphylococcus aureus enterotoxins, alkaloid to ...200919280130
genetics and virulence association of the shigella flexneri sit iron transport system.the sit-encoded iron transport system is present within pathogenicity islands in all shigella spp. and some pathogenic escherichia coli strains. the islands contain numerous insertion elements and sequences with homology to bacteriophage genes. the shigella flexneri sit genes can be lost as a result of deletion within the island. the formation of deletions was dependent upon reca and occurred at relatively high frequency. this suggests that the sit region is inherently unstable, yet sit genes ar ...200919289511
acute non-outbreak shigellosis: ten years experience in southern taiwan.we conducted a retrospective study of both the clinical and laboratory characteristics of shigellosis in southern taiwan.200919292940
characterization of fluoroquinolone-resistant shigella flexneri in hangzhou area of china.the aim of this study was to characterize fluoroquinolone-resistant shigella and determine whether the qnr and aac(6')-ib-cr genes could contribute to sporadic shigellosis at the clinic in the hangzhou area of china.200919297378
serodiversity and antimicrobial resistance pattern of shigella isolates at gondar university teaching hospital, northwest ethiopia.the aims of this study were to determine the distribution of serogroups and serotypes as well as the antimicrobial resistance pattern of shigella isolates from gondar patients with acute diarrhea. a cross-sectional study was conducted from august 2006 to february 2008. stool specimens were received from study subjects and cultured. isolates were confirmed by biochemical and serological tests. the isolates were tested for antimicrobial susceptibility by the disc diffusion method. of the 1,200 sto ...200919305047
structural mimicry of o-antigen by a peptide revealed in a complex with an antibody raised against shigella flexneri serotype 2a.the use of carbohydrate-mimicking peptides to induce immune responses against surface polysaccharides of pathogenic bacteria offers a novel approach to vaccine development. factors governing antigenic and immunogenic mimicry, however, are complex and poorly understood. we have addressed this question using the anti-lipopolysaccharide monoclonal antibody f22-4, which was raised against shigella flexneri serotype 2a and shown to protect against homologous infection in a mouse model. in a previous ...200919328810
antimicrobial susceptibility and mechanisms of resistance in shigella and salmonella isolates from children under five years of age with diarrhea in rural mozambique.the antimicrobial susceptibility and mechanisms of resistance of 109 shigella and 40 salmonella isolates from children with diarrhea in southern mozambique were assessed. the susceptibility to seven antimicrobial agents was tested by disk diffusion, and mechanisms of resistance were searched by pcr or colorimetric method. a high proportion of shigella isolates were resistant to chloramphenicol (chl) (52%), ampicillin (amp) (56%), tetracycline (tet) (66%), and trimethoprim-sulfamethoxazole (sxt) ...200919332670
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