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structurally distinct bacterial tbc-like gaps link arf gtpase to rab1 inactivation to counteract host defenses.rab gtpases are frequent targets of vacuole-living bacterial pathogens for appropriate trafficking of the vacuole. here we discover that bacterial effectors including vira from nonvacuole shigella flexneri and espg from extracellular enteropathogenic escherichia coli (epec) harbor tbc-like dual-finger motifs and exhibits potent rabgap activities. specific inactivation of rab1 by vira/espg disrupts er-to-golgi trafficking. s. flexneri intracellular persistence requires vira tbc-like gap activity ...201222939626
quinolone-resistant shigella flexneri isolated in a patient who travelled to india.we report a recent case in which ciprofloxacin-resistant shigella flexneri was isolated from a 23-yr-old female patient with a history of travel to india. prior to her admission to our internal medicine department, she experienced symptoms of high fever and generalized weakness from continuous watery diarrhea that developed midway during the trip. s. flexneri was isolated from the stool culture. despite initial treatment with ciprofloxacin, the stool cultures continued to show s. flexneri growth ...201222950074
spontaneous formation of ipab ion channels in host cell membranes reveals how shigella induces pyroptosis in macrophages.the gram-negative bacterium shigella flexneri invades the colonic epithelium and causes bacillary dysentery. s. flexneri requires the virulence factor invasion plasmid antigen b (ipab) to invade host cells, escape from the phagosome and induce macrophage cell death. the mechanism by which ipab functions remains unclear. here, we show that purified ipab spontaneously oligomerizes and inserts into the plasma membrane of target cells forming cation selective ion channels. after internalization, ipa ...201222951981
microbiota, innate immune system, and gastrointestinal muscle: ongoing studies.to test the activities of culture-extracted or commercially available toll-like receptors (tlrs) ligands to establish their direct impact on target gastrointestinal motor cells.201222955360
high load of multi-drug resistant nosocomial neonatal pathogens carried by cockroaches in a neonatal intensive care unit at tikur anbessa specialized hospital, addis ababa, ethiopia. 201222958880
metal based new triazoles: their synthesis, characterization and antibacterial/antifungal activities.a series of new triazoles and their oxovanadium(iv) complexes have been synthesized, characterized and evaluated for antibacterial/antifungal properties. the new schiff bases ligands (l(1))-(l(5)) were prepared by the condensation reaction of 3,5-diamino-1,2,4-triazole with 2-hydroxy-1-naphthaldehyde, pyrrole-2-carboxaldehyde, pyridine-2-carboxaldehyde, 2-acetyl pyridine and 2-methoxy benzaldehyde. the structures of the ligands have been established on the basis of their physical, spectral (ir, ...201222982389
glutamate decarboxylase-dependent acid resistance in orally acquired bacteria: function, distribution and biomedical implications of the gadbc operon.for successful colonization of the mammalian host, orally acquired bacteria must overcome the extreme acidic stress (ph < 2.5) encountered during transit through the host stomach. the glutamate-dependent acid resistance (gdar) system is by far the most potent acid resistance system in commensal and pathogenic escherichia coli, shigella flexneri, listeria monocytogenes and lactococcus lactis. gdar requires the activity of glutamate decarboxylase (gadb), an intracellular plp-dependent enzyme which ...201222995042
quantification of viable but nonculturable bacterial pathogens in anaerobic digested sludge.enteric bacterial pathogens in sewage sludge easily become viable but nonculturable (vbnc) during anaerobic digestion, which escape detection by standard culture methods and pose a potential health risk. in this study, a method that is combining the standard culture method with the reverse transcription quantitative pcr (rt-qpcr) assay was developed for the quantification of bacterial pathogens in the vbnc state. the cycle threshold (ct) values from rt-qpcr assays were linear to the bacterial nu ...201322996281
expression of shigella flexneri gluq-rs gene is linked to dksa and controlled by a transcriptional terminator.glutamyl queuosine-trna(asp) synthetase (gluq-rs) is a paralog of the catalytic domain of glutamyl-trna synthetase and catalyzes the formation of glutamyl-queuosine on the wobble position of trna(asp). here we analyze the transcription of its gene in shigella flexneri, where it is found downstream of dksa, which encodes a transcriptional regulator involved in stress responses.201223035718
effect of x-ray treatments on pathogenic bacteria, inherent microbiota, color, and texture on parsley leaves.this work is a part of systematic studies of the effect of x-ray treatments on fresh produce. the main objective of this investigation was to study the effects of x-ray treatments in reducing the concentration of artificially inoculated escherichia coli o157:h7, listeria monocytogenes, salmonella enterica, and shigella flexneri, and inherent microbiota on parsley leaves. the secondary objective was to study the effects of x-ray treatments on color and texture parameters on treated parsley leaves ...201223035726
towards a non-living vaccine against shigella flexneri: from the inactivation procedure to protection studies.shigellosis is one of the leading causes of diarrhea worldwide with more than 165 million cases annually. hence, a vaccine against this disease is a priority, but no licensed vaccine is still available. considering target population as well as intrinsic risks of live attenuated vaccines, non-living strategies appear as the most promising candidates. remarkably, the preservation of antigenic properties is a major concern since inactivation methods of bacteria affect these qualities. we previously ...201323046911
a novel plasmid-encoded serotype conversion mechanism through addition of phosphoethanolamine to the o-antigen of shigella flexneri.shigella flexneri is the major pathogen causing bacillary dysentery in developing countries. s. flexneri is divided into at least 16 serotypes based on the combination of antigenic determinants present in the o-antigen. all the serotypes (except for serotype 6) share a basic o-unit containing one n-acetyl-d-glucosamine and three l-rhamnose residues, whereas differences between the serotypes are conferred by phage-encoded glucosylation and/or o-acetylation. serotype xv is a newly emerged and the ...201223049947
surveillance of antibiotic susceptibility pattern among shigella flexneri strain isolated in nagpur district during three years period, january 2009-january 2012.in the few cases of childhood dirrhea that require the antimicrobial therapy, the correct choice of the drug depends on detailed previous knowledge of local strains and pattern of antimicrobial resistance. shigellosis is one of the most improtant examples of this group of intestinal infections. in order to establish such parameters in nagpur city, this study was carried out to determine the antimcrobial resistance profile of shigella flexneri isolated from patients suffering from diahhrea admitt ...201023051941
spontaneous mutation frequency and molecular mechanisms of shigella flexneri fluoroquinolone resistance under antibiotic selective stress.the incidence of fluoroquinolone-resistant shigella strains has risen rapidly, presumably in response to ciprofloxacin antibiotic stress. understanding the molecular mechanisms underlying this resistance phenotype is critical to developing novel and effective therapeutic strategies. in this study, the frequency of ciprofloxacin-induced mutation was measured in antibiotic resistance genes (gyra, gyrb, parc, pare, maror, and mara) of shigella flexneri. the s. flexneri 2a strain 301 was cultured on ...201323070800
shigellosis outbreak associated with contaminated well water in a rural elementary school: sichuan province, china, june 7-16, 2009.we investigated a shigellosis outbreak in an elementary school to identify the source of infection, mode of transmission and risk factors for illness.201223071767
lessons from anaplasma phagocytophilum: chromatin remodeling by bacterial effectors.bacterial pathogens can alter global host gene expression via histone modifications and chromatin remodeling in order to subvert host responses, including those involved with innate immunity, allowing for bacterial survival. shigella flexneri, listeria monocytogenes, chlamydia trachomatis, and anaplasma phagocytophilum express effector proteins that modify host histones and chromatin structure. a. phagocytophilum modulates granulocyte respiratory burst in part by dampening transcription of sever ...201223082961
myosin-x facilitates shigella-induced membrane protrusions and cell-to-cell spread.the intracellular pathogen shigella flexneri forms membrane protrusions to spread from cell to cell. as protrusions form, myosin-x (myo10) localizes to shigella. electron micrographs of immunogold-labelled shigella-infected hela cells reveal that myo10 concentrates at the bases and along the sides of bacteria within membrane protrusions. time-lapse video microscopy shows that a full-length myo10 gfp-construct cycles along the sides of shigella within the membrane protrusions as these structures ...201323083060
shigella flexneri t3ss effector ipah4.5 modulates the host inflammatory response via interaction with nf-κb p65 protein.shigella species possess a type iii secretion system (t3ss), which is required for human infection and that delivers effector proteins into target host cells. here, we show that the effector, ipah4.5 dampens the pro-inflammatory cytokine response. in both the sereny test and a murine lung infection model, the shigella δipah4.5 mutant strain caused more severe inflammatory responses and significantly induced higher pro-inflammatory cytokine levels (mip-2 and tnf-α) in the lung homogenates of wild ...201323083102
synthesis of monodispersed silver nanoparticles using hibiscus cannabinus leaf extract and its antimicrobial activity.synthesis of silver nanoparticles using leaf extract of hibiscus cannabinus has been investigated. the influences of different concentration of h. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. the synthesized nanoparticles were characterized using uv-vis spectroscopy, fourier transform infrared spectroscopy (ftir), x-ray diffraction (xrd) and transmission electron microscopy (tem). the p ...201323103459
the nucleotide sequence of shigella flexneri 1a: a common indian isolate.we report complete sequences of 2 genes of s.flexneri 1a an indian isolate for the first time. shigella is causative agent of shigellosis or bacillary dysentery. genomic library was constructed by shotgun approach. sequencing was carried out using big dye terminator chemistry using abi 3730 48 capillary dna analyzer. 170 recombinants were subjected to nucleotide sequencing. sequence data was analyzed, of these 2 clones showed presence of complete genes out of the total clones sequenced. annotati ...200923105823
evaluation of probiotic properties of lactobacillus plantarum strains isolated from chinese sauerkraut.lactobacillus plantarum strains isolated and identified from naturally-fermented chinese sauerkraut were examined in vitro for potential probiotic properties and in vivo for cholesterol-lowering effect in mice. among 7 isolated l. plantarum strains, strains s2-5 and s4-1 were found to possess desirable probiotic properties including ability to survive at ph 2.0 for 60 min, tolerate pancreatin and bile salts, adhere to caco-2 cells, produce high β-galactosidase activity and antimicrobial activity ...201323117677
molecular structure, normal coordinate analysis, harmonic vibrational frequencies, natural bond orbital, td-dft calculations and biological activity analysis of antioxidant drug 7-hydroxycoumarin.in this work, we report harmonic vibrational frequencies, molecular structure, nbo and homo, lumo analysis of umbelliferone also known as 7-hydroxycoumarin (7hc). the optimized geometric bond lengths and bond angles obtained by computation (monomer and dimmer) shows good agreement with experimental xrd data. harmonic frequencies of 7hc were determined and analyzed by dft utilizing 6-311+g(d,p) as basis set. the assignments of the vibrational spectra have been carried out with the help of normal ...201323123244
connexin 26 facilitates gastrointestinal bacterial infection in vitro.escherichia coli, including enteropathogenic e. coli (epec), represents the most common cause of diarrhoea worldwide and is therefore a serious public health burden. treatment for gastrointestinal pathogens is hindered by the emergence of multiple antibiotic resistance, leading to the requirement for the development of new therapies. a variety of mechanisms act in combination to mediate gastrointestinal-bacterial-associated diarrhoea development. for example, epec infection of enterocytes induce ...201323138568
outer membrane protein a (ompa): a new player in shigella flexneri protrusion formation and inter-cellular spreading.outer membrane protein a (ompa) is a multifaceted predominant outer membrane protein of escherichia coli and other enterobacteriaceae whose role in the pathogenesis of various bacterial infections has recently been recognized. here, the role of ompa on the virulence of shigella flexneri has been investigated. an ompa mutant of wild-type s. flexneri 5a strain m90t was constructed (strain hnd92) and it was shown to be severely impaired in cell-to-cell spreading since it failed to plaque on hela ce ...201223166731
chromosomal and plasmid-encoded factors of shigella flexneri induce secretogenic activity ex vivo.shigella flexneri is a gram-negative, facultative intracellular pathogen that causes millions of cases of watery or bloody diarrhea annually, resulting in significant global mortality. watery diarrhea is thought to arise in the jejunum, and subsequent bloody diarrhea occurs as a result of invasion of the colonic epithelium. previous literature has demonstrated that shigella encodes enterotoxins, both chromosomally and on the 220 kilobase virulence plasmid. the shigellaenterotoxins 1 and 2 (shet1 ...201223166804
in vitro antimicrobial activity on clinical microbial strains and antioxidant properties of artemisia parviflora.artemisia parviflora leaf extracts were evaluated for potential antimicrobial and antioxidant properties. antimicrobial susceptibility assay was performed against ten standard reference bacterial strains. antioxidant activity was analyzed using the ferric thiocyanate and 2, 2-diphenyl-1-picrylhydrazyl (dpph) assays. radical scavenging activity and total phenolic content were compared. phytochemical analyses were performed to identify the major bioactive constitution of the plant extract.201223171441
antibacterial, antifungal and antioxidant activities of the ethanol extract of the stem bark of clausena heptaphylla.there is wide spread interest in drugs derived from plants as green medicine is believed to be safe and dependable, compared with costly synthetic drugs that have adverse effects.201223181593
comparison of ims platforms for detecting and recovering escherichia coli o157 and shigella flexneri in foods.two automated platforms using immunomagnetic separation technology were compared for detecting and recovering escherichia coli o157 in ground beef and sprouts and shigella flexneri in green onions. the foods were inoculated with <20 cfu/25 g and tested at 5 and 24 h postincubation. immunomagnetic beads were mixed with food enrichments, processed through the pathatrix auto or kingfisher flex, and tested by real-time pcr (qpcr) and recovery on selective agars. at 5 h, the pathatrix auto detected e ...201323190790
immobilization of lysozyme-clea onto electrospun chitosan nanofiber for effective antibacterial applications.chitosan (cs) nanofibers with a diameter of 150-200nm were fabricated from a mixed chitosan/poly (vinyl alcohol) (pva) solution by the electrospinning method. the nascent cs/pva nanofibers were treated with 0.5m naoh solution to make stable cs nanofibers by removing pva under aqueous conditions. hen egg-white lysozyme was immobilized on electrospun cs nanofibers via cross-linked enzyme aggregates (cleas) and used for effective and continuous antibacterial applications. the maximum amount of lyso ...201323201775
multi-locus sequence typing (mlst) and repetitive extragenic palindromic polymerase chain reaction (rep-pcr), characterization of shigella spp. over two decades in tianjin china.to understand the change of the dominant serogroup of shigella spp., their antimicrobial resistance over more than two decades in tianjin, their phylogenetic similarity and to determine their evolutionary biology by using rep-pcr and mlst in order to study their epidemiological character. multi-locus sequence typing was performed to determine their lineage and phylogenetic similarity. rep-pcr typing was used to study the homology of their genomic dna. the isolated rate of group d shigella in 200 ...201223205184
architecture of the major component of the type iii secretion system export apparatus.type iii secretion systems (t3sss) are bacterial membrane-embedded nanomachines designed to export specifically targeted proteins from the bacterial cytoplasm. secretion through t3ss is governed by a subset of inner membrane proteins termed the 'export apparatus'. we show that a key member of the shigella flexneri export apparatus, mxia, assembles into a ring essential for secretion in vivo. the ring-forming interfaces are well-conserved in both nonflagellar and flagellar homologs, implying that ...201223222644
bruton's tyrosine kinase regulates shigella flexneri dissemination in ht-29 intestinal cells.shigella flexneri is a gram-negative intracellular pathogen that infects the intestinal epithelium and utilizes actin-based motility to spread from cell to cell. s. flexneri actin-based motility has been characterized in various cell lines, but studies in intestinal cells are limited. here we characterized s. flexneri actin-based motility in ht-29 intestinal cells. in agreement with studies conducted in various cell lines, we showed that s. flexneri relies on neural wiskott-aldrich syndrome prot ...201323230296
phage inactivation of foodborne shigella on ready-to-eat spiced chicken.shigellosis, also called bacillary dysentery, is an infectious disease caused by shigella species, including shigella flexneri, shigella dysenteriae, shigella sonnei, and shigella boydii. infection with s. flexneri can result in epidemics, and shigella-contaminated food is often the source of infection, such as ready-to-eat spiced chicken and duck. therefore, we investigated the ability of shigella phages to inhibit pathogenic shigella spp. in ready-to-eat spiced chicken. food samples were inocu ...201323243250
human plasma-derived polymeric iga and igm antibodies associate with secretory component to yield biologically active secretory-like antibodies.immunotherapy with monoclonal and polyclonal immunoglobulin is successfully applied to improve many clinical conditions, including infection, autoimmune diseases, or immunodeficiency. most immunoglobulin products, recombinant or plasma-derived, are based on igg antibodies, whereas to date, the use of iga for therapeutic application has remained anecdotal. in particular, purification or production of large quantities of secretory iga (siga) for potential mucosal application has not been achieved. ...201323250751
one-step sensitive detection of salmonella typhimurium by coupling magnetic capture and fluorescence identification with functional nanospheres.sensitive, rapid, and reliable detection of bacteria has always been pursued due to the great threat of the bacteria to human health. in this study, a convenient one-step strategy for detecting salmonella typhimurium was developed. immunomagnetic nanospheres (imns) and immunofluorescent nanospheres (ifns) were used to specifically capture and recognize s. typhimurium simultaneously. after magnetic separation, the sandwich immune complexes (imns-bacteria-ifns) were detected under a fluorescence m ...201323256523
o-antigen structure of shigella flexneri serotype yv and effect of the lpt-o gene variation on phosphoethanolamine modification of s. flexneri o-antigens.shigella flexneri is the major human pathogen causing shigellosis. o-antigens of all s. flexneri serotypes (except for serotype 6) share the →2)-α-l-rhap(iii)-(1 → 2)-α-l-rhap(ii)-(1 → 3)-α-l-rhap(i)-(1 → 3)-β-d-glcpnac-(1→ basic o-unit, whereas differences between the serotypes are conferred by phage-encoded glucosylation and/or o-acetylation at various positions. recently, in serotype x and 4a variants called xv and 4av, respectively, o-antigen modification with phosphoethanolamine (petn) has ...201323283000
[calpain activation by shigella flexneri regulates key steps in the life and death of bacterium's epithelial niche]. 201223290392
technological and probiotic potential of bgra43 a natural isolate of lactobacillus helveticus.lactobacillus helveticus bgra43 is a human intestinal isolate showing antimicrobial activity, amongst others, against yersinia enterocolitica, shigella sonnei, shigella flexneri, and streptococcus pneumoniae. bgra43 produces prth proteinase with proteolytic activity on both casein and β-lactoglobulin (blg). bgra43 is able to reduce the allergenicity of blg. bioactive peptides released in bgra43 fermented milk are potent modulators of innate immunity by modulating the production of proinflammator ...201323346083
antidiarrhoeal and antimicrobial activity of calpurnia aurea leaf extract.in ethiopia, calpurnia aurea is used for the treatment of syphilis, malaria, rabies, diabetes, hypertension, diarrhoea, leishmaniasis, trachoma, elephantiasis, fungal diseases and different swellings. however, despite its traditional usage as an antidiarrhoeal and antimicrobial agent, there is limited or no information regarding its effectiveness and mode of action in diarrhoea which may be caused by shigella flexneri, staphylococcus aureus, escherichia coli and salmonella typhi. hence, we evalu ...201323351272
analysis of soluble protein complexes in shigella flexneri reveals the influence of temperature on the amount of lipopolysaccharide.shigella flexneri, which is closely related to escherichia coli, is the most common cause of the endemic form of shigellosis. in this study, 53 homomultimeric protein complexes and nine heteromultimeric protein complexes from s. flexneri 2a strain 2457t were separated and identified. among these, three potential homomultimeric protein complexes had not been previously described. one complex, thought to be composed of 12 phon1 subunits, is a periplasmic protein with an unknown physiological role ...201323378524
deletion of pic results in decreased virulence for a clinical isolate of shigella flexneri 2a from china.shigella is a major pathogen responsible for bacillary dysentery, a severe form of shigellosis. severity of the disease depends on the virulence of the infecting strain. shigella pathogenicity is a multi-gene phenomenon, involving the participation of genes on an unstable large virulence plasmid and chromosomal pathogenicity islands.201323391153
residues located inside the escherichia coli fepe protein oligomer are essential for lipopolysaccharide o-antigen modal chain length regulation.the escherichia coli o157 : h7 fepe protein regulates lipopolysaccharide (lps) o-antigen (oag) chain length to confer a very long modal chain length of >80 oag repeat units (rus). the mechanism by which fepe regulates oag modal chain length and the regions within it that are important for its function remain unclear. studies on the structure of fepe show that the protein oligomerizes. however, the exact size of the oligomer is in dispute, further hampering our understanding of its mechanism. gui ...201323393150
identification of shigella flexneri icsa residues affecting interaction with n-wasp, and evidence for icsa-icsa co-operative interaction.the shigella flexneri icsa (virg) protein is a polarly distributed outer membrane protein that is a fundamental virulence factor which interacts with neural wiskott-aldrich syndrome protein (n-wasp). the activated n-wasp then activates the arp2/3 complex which initiates de novo actin nucleation and polymerisation to form f-actin comet tails and allows bacterial cell-to-cell spreading. in a previous study, icsa was found to have three n-wasp interacting regions (irs): ir i (aa 185-312), ir ii (aa ...201323405119
shigellosis outbreak at addis ababa university: march-april 2010.between 2006 and 2008, there have been various reports of diarrhea with blood in ethiopia and also reports of shigelloses outbreaks in some parts of the country. in march 2010, addis ababa university (aau) technology campus reported occurrence of an outbreak of diarrheal illness among students.201123409399
decreased susceptibility to antimicrobials among shigella flexneri isolates in manipal, south india--a 5 year hospital based study.shigellosis is endemic in many developing countries and an important cause of bloody diarrhea worldwide. our study was undertaken as a continuation of our earlier study during 2001 - 2006.the aim of this study was to monitor changes in shigella serogroups and resistance patterns to antimicrobials among shigella isolates. two thousand one hundred fecal samples were obtained from patients with diarrhea during june 2006-june 2011. isolates were identified by standard microbiological techniques as s ...201223413708
isolation and genomic characterization of sfi, a serotype-converting bacteriophage of shigella flexneri.all shigella flexneri serotypes except serotype 6 share a common o-antigen tetrasaccharide backbone and nearly all variations between serotypes are due to glucosyl and/or o-acetyl modifications of the common o unit mediated by glycosyltransferases encoded by serotype-converting bacteriophages. several s. flexneri serotype-converting phages including sfv, sfx, sf6 and sfii have been isolated and characterized. however, s. flexneri serotype-converting phage sfi which encodes a type i modification ...201323414301
antimicrobial and antioxidant activities of alcoholic extracts of rumex dentatus l.in-vitro antimicrobial and antioxidant activities of various concentrations ranging from 150 to 500 μg/ml of alcoholic (methanol and ethanol) extracts of rumex dentatus were analyzed on different clinical bacterial strains (shigella flexneri, klebsiella pneumoniae, escherichia coli, pseudomonas aeruginosa, salmonella typhimurium, staphylococcus aureus) and fungal strains (aspergillus versicolor, aspergillus flavus, acremonium spp., penicillium dimorphosporum, candida albicans, candida kruesie, c ...201323415966
shigella impairs t lymphocyte dynamics in vivo.the gram-negative enteroinvasive bacterium shigella flexneri is responsible for the endemic form of bacillary dysentery, an acute rectocolitis in humans. s. flexneri uses a type iii secretion system to inject effector proteins into host cells, thus diverting cellular functions to its own benefit. protective immunity to reinfection requires several rounds of infection to be elicited and is short-lasting, suggesting that s. flexneri interferes with the priming of specific immunity. considering the ...201323417297
shigella in brazilian children with acute diarrhoea: prevalence, antimicrobial resistance and virulence genes.diarrhoeal disease is still considered a major cause of morbidity and mortality among children. among diarrhoeagenic agents, shigella should be highlighted due to its prevalence and the severity of the associated disease. here, we assessed shigella prevalence, drug susceptibility and virulence factors. faeces from 157 children with diarrhoea who sought treatment at the children's hospital joão paulo ii, a reference children´s hospital in belo horizonte, state of minas gerais, brazil, were cultur ...201323440111
[bacteraemia due to shigella flexneri serotype 6 in two patients with aids].infections due to shigella usually remain localized to the digestive tract and are self-limited. bacteremia is a potentially lethal complication that can occur in immunocompromised patients. we describe two episodes of bacteremia caused by shigella in two adults with aids. in both patients, s. flexneri was recovered from stool and blood samples. the isolates belonged to serotype 6, were resistant only to trimethoprim-sulfamethoxazole and showed a similar band profile by pulsed-field gel electrop ...201323450419
tmrna is essential in shigella flexneri.nonstop mrnas pose a challenge for bacteria, because translation cannot terminate efficiently without a stop codon. the trans-translation pathway resolves nonstop translation complexes by removing the nonstop mrna, the incomplete protein, and the stalled ribosome. p1 co-transduction experiments demonstrated that tmrna, a key component of the trans-translation pathway, is essential for viability in shigella flexneri. tmrna was previously shown to be dispensable in the closely related species esch ...201323451240
screening of solvent dependent antibacterial activity of prunus domestica.fruit of prunus domestica was extracted in ethanol. the ethanol extract was further extracted with two solvents ethyl acetate and chloroform. the crude ethanol extract and two fractions (ethyl acetate and chloroform) were screened for their antibacterial activity using the agar well diffusion method .they were tested against nine bacteria; five gram positive bacteria (staphylococcus aureus, streptococcuc intermedius, bacillus cereus, bacillus pumilus) and four gram negative bacteria (eschrichia ...201323455215
multidrug-resistant shigella flexneri bacteremia in an immunocompetent adult. 201223455829
oligomeric states of the shigella translocator protein ipab provide structural insights into formation of the type iii secretion translocon.the shigella flexneri type iii secretion system (t3ss) senses contact with human intestinal cells and injects effector proteins that promote pathogen entry as the first step in causing life threatening bacillary dysentery (shigellosis). the shigella type iii secretion apparatus (t3sa) consists of an anchoring basal body, an exposed needle, and a temporally assembled tip complex. exposure to environmental small molecules recruits ipab, the first hydrophobic translocator protein, to the maturing t ...201323456854
recombinant heat shock protein 60 (hsp60/groel) of salmonella enterica serovar typhi elicits cross-protection against multiple bacterial pathogens in mice.heat shock proteins (hsps) or stress proteins are recognized as protective antigens against a wide range of bacterial diseases. conservation of hsps across different life forms also appears to contribute to the antigenicity of these proteins. due to their high sequence homology, there exists an immunological cross-recognition between different bacterial species. in the present study, we evaluated the efficacy of recombinant groel of salmonella enterica serovar typhi as a vaccine candidate agains ...201323474314
drug resistant shigella flexneri in & around dibrugarh, north-east india.shigella flexneri is the most common species of shigella causing diarrhoea and dysentery in asia including india. multidrug resistance in shigella species has been reported worldwide and there is rising concern regarding development of fluoroquinolone resistance. this study was undertaken to find out the resistance pattern of sh. flexneri, the commonest shigella isolated in dibrugarh, north east india, including detection of fluoroquinolone resistance and extended spectrum beta lactamases.201323481070
[sensitivity to antibiotics and genetic support to resistance of shigella flexneri strains isolated in dakar from 2001 to 2010].diarrheal diseases remain a leading cause of death with 14.7 million deaths in 2001 and 26% of global mortality worldwide according to who. shigella species are prevalent in tropical areas; they are present all the year, with epidemic outbreaks in rainy season. between 2001 and 2010 one hundred ninety (190) strains of shigella flexneri isolated from national senegalese enterobacteriaceae center located at the pasteur institute in dakar were studied. susceptibility was performed by antibiogram fo ...201323483461
safety assessment and probiotic evaluation of enterococcus faecium yf5 isolated from sourdough.enterococcus faecium yf5, a strain previously isolated from sourdough, was assessed for safety and probiotic potential. its virulence and antibiotic resistant phenotypes (cytolysin and gelatinase production, antibiotic susceptibility) and genes (cyla, gele, ace, agg, esp, and vana) were surveyed. results indicated that the tested virulence determinants were nontoxic. in addition, e. faecium yf5 was sensitive to 3 antibiotics such as amoxicillin, vancomycin, and chloramphenicol. furthermore, resu ...201323488799
synthesis and concentration dependent antibacterial activities of cuo nanoflakes.we report, synthesis and antibacterial activities of cuo nanoflakes. cuo nanoparticles are prepared at room temperature through sol-gel method. x-ray diffraction studies show the particles are monoclinic (crystalline) in nature. scanning electron microscopy (sem) images clearly show that the prepared particles are flake like in structure. fourier transform infrared (ftir) spectra exhibits three different bands that correspond to the au and bu modes. antibacterial studies were performed on shigel ...201323498227
use of population-based surveillance to define the high incidence of shigellosis in an urban slum in nairobi, kenya.worldwide, shigella causes an estimated 160 million infections and >1 million deaths annually. however, limited incidence data are available from african urban slums. we investigated the epidemiology of shigellosis and drug susceptibility patterns within a densely populated urban settlement in nairobi, kenya through population-based surveillance.201323505506
cefotaximase and ampc-producing shigella flexneri in case of dysentery from southern india.diarrhoea and dysentery caused by shigella spp. are major public health concerns. emerging multidrug resistance (mdr) in this pathogen further complicates this disease. extended spectrum β-lactamases (esbls) have been described in this pathogen, which significantly compromises the treatment options for shigellosis. the usual esbls seen are sulfhydryl variable (shv)-type; cefotaximases (ctx-m) are very uncommonly detected. here, we report a ctx-m type and ampc-producing shigella flexneri from a t ...201323508436
topological investigation of glucosyltransferase v in shigella flexneri using the substituted cysteine accessibility method.modification of the lipopolysaccharide o-antigen of shigella converts the serotype, which is significant as acquired immune responses are serotype specific. glucosyltransferases (gtrs) modify the o-antigen by the addition of glucosyl-groups; however the precise mechanism of o-antigen modification is not fully understood. this study aims to substantiate inferences made on the gtrv topological structure using the substituted cysteine accessibility method (scam). twenty-one amino acid residues were ...201323534399
proteolytic elimination of n-myristoyl modifications by the shigella virulence factor ipaj.protein n-myristoylation is a 14-carbon fatty-acid modification that is conserved across eukaryotic species and occurs on nearly 1% of the cellular proteome. the ability of the myristoyl group to facilitate dynamic protein-protein and protein-membrane interactions (known as the myristoyl switch) makes it an essential feature of many signal transduction systems. thus pathogenic strategies that facilitate protein demyristoylation would markedly alter the signalling landscape of infected host cells ...201323535599
structural basis for the recognition of ubc13 by the shigella flexneri effector ospi.ubc13 is a ubiquitin-conjugating enzyme that plays a key role in the nuclear factor-κb signal transduction pathway in human diseases. the shigella flexneri effector ospi affects inflammatory responses by catalyzing the deamidation of a specific glutamine residue at position 100 in ubc13 during infection. this modification prevents the activation of the tnf (tumor necrosis factor) receptor-associated factor 6, leading to modulation of the diacylglycerol-cbm (card-bcl10-malt1) complex-tnf receptor ...201323542009
characterization of the ospz promoter in shigella flexneri and its regulation by virb and h-ns.ospz is an effector protein of the type iii secretion system in shigella spp. that downregulates the human inflammatory response during bacterial infection. the ospz gene is located on the large virulence plasmid of shigella. many genes on this plasmid are transcriptionally repressed by the nucleoid structuring protein h-ns and derepressed by virb, a dna-binding protein that displays homology to the plasmid partitioning proteins parb and sopb. in this study, we characterized the ospz promoter an ...201323543709
prevalence and trends of aminoglycoside resistance in shigella worldwide, 1999-2010.shigellosis causes diarrheal disease in humans in both developed and developing countries, and multi-drug resistance in shigella is an emerging problem. understanding changing resistance patterns is important in determining appropriate antibiotic treatments. this meta-analysis systematically evaluated aminoglycoside resistance in shigella. a systematic review was constructed based on medline and embase databases. random-effect models or fixed-effect models were used based on p value considering ...201323554801
the common structural architecture of shigella flexneri and salmonella typhimurium type three secretion needles.the type three secretion system (t3ss), or injectisome, is a macromolecular infection machinery present in many pathogenic gram-negative bacteria. it consists of a basal body, anchored in both bacterial membranes, and a hollow needle through which effector proteins are delivered into the target host cell. two different architectures of the t3ss needle have been previously proposed. first, an atomic model of the salmonella typhimurium needle was generated from solid-state nmr data. the needle sub ...201323555258
cytotoxic (a549) and antimicrobial effects of methylobacterium sp. isolate (eri-135) from nilgiris forest soil, india.to assess the antimicrobial and cytotoxic effects of methylobacterium sp. isolated from soil sample of doddabetta forest, nilgiris, western ghats of tamil nadu.201223570000
multiplexed immunoassay to assess shigella-specific antibody responses.infection with shigella spp. results in bacillary dysentery and a systemic and mucosal antibody response. the immune response is directed at multiple antigens, including lps and the invasin plasmid antigen (ipa) proteins, and is capable of conferring short-term, serotype-specific protection. both live-attenuated and several subunit vaccine approaches have focused on inducing a pronounced mucosal immune response directed to the same antigens recognized after natural infection. traditionally, shig ...201323583496
in vitro anti-biofilm and anti-bacterial activity of junceella juncea for its biomedical application.to investigate the anti-biofilm and anti-bacterial activity of junceella juncea (j. juncea) against biofilm forming pathogenic strains.201223593571
structure of the o-antigen of a novel shigella flexneri serotype, 1d (i: 7,8).recently, strains of a novel shigella flexneri serotype called 1d have been isolated from diarrheal patients in china. they are distinguished by the presence of a hitherto unknown combination of type o-factor i and group o-factor 7,8, both associated with lateral α-d-glucosyl groups on the basal linear o-polysaccharide. a serologically identical strain, 036_1d, has been constructed in the laboratory by sequential infection of serotype y by serotype-converting bacteriophages sfx and sfi. in this ...201323603189
1,1-diphenyl,2-picrylhydrazyl free radical scavenging, bactericidal, fungicidal and leishmanicidal properties of teucrium stocksianum.in the present study, we evaluated the pharmacological and toxicological effects of teucrium stocksianum. the crude extract of t. stocksianum (ts.cr) and its subsequent organic fractions: n-hexane (ts.hex), chloroform (ts.chcl3) and ethyl acetate (ts.etac) exhibited 1,1-diphenyl,2-picrylhydrazyl free radical scavenging activity with different potencies. ts.etac was found to be most potent. ts.cr, ts.hex, ts.chcl3 and ts.etac showed significant bactericidal activity against escherichia coli, stap ...201523625908
genetic characterization of antimicrobial resistance of shigella flexneri 1c isolates from patients in egypt and pakistan.shigella flexneri serotype 1c emerged as a critical isolate from children in egypt and pakistan. the pattern of antimicrobial susceptibility (ams) and resistance genes of this serotype have yet to be characterized.201323638855
[virulence genes and pathogenicity of shigella flexneri xv isolated in beijing].to understand the biochemical characteristics, virulence genes and pathogenicity of shigella flexneri xv isolated in beijing.201323648252
shigella antigen-specific b memory cells are associated with decreased disease severity in subjects challenged with wild-type shigella flexneri 2a.the role of shigella-specific b memory (bm) in protection has not been evaluated in human challenge studies. we utilized cryopreserved pre- and post-challenge peripheral blood mononuclear cells and sera from wild-type shigella flexneri 2a (wt-2457t) challenges. challenged volunteers were either naïve or subjects who had previously ingested wt-2457t or been immunized with hybrid escherichia coli-shigella live oral candidate vaccine (ecsf2a-2). bm and antibody titers were measured against lipopoly ...201323649043
the antimicrobial effect of lactobacillus casei culture supernatant against multiple drug resistant clinical isolates of shigella sonnei and shigella flexneri in vitro.shigellosis remains an important public health problem in developing countries with s. sonnei and s. flexneri in us, europe and in asian countries being of importance.201323682323
the shigella ospc3 effector inhibits caspase-4, antagonizes inflammatory cell death, and promotes epithelial infection.caspase-mediated inflammatory cell death acts as an intrinsic defense mechanism against infection. bacterial pathogens deploy countermeasures against inflammatory cell death, but the mechanisms by which they do this remain largely unclear. in a screen for shigella flexneri effectors that regulate cell death during infection, we discovered that shigella infection induced acute inflammatory, caspase-4-dependent epithelial cell death, which is counteracted by the bacterial ospc3 effector. ospc3 int ...201323684308
multi-serotype outer membrane vesicles of shigellae confer passive protection to the neonatal mice against shigellosis.recently, we have demonstrated, immunization of adult female mice with outer membrane vesicles (omvs) of shigella boydii type 4 protected their offspring passively from shigellosis. in our present study, we have advanced our research by formulating multi-serotype outer membrane vesicles (momvs), mixing the omvs of shigella dysenteriae 1 δstx, shigella flexneri 2a, 3a and 6, s. boydii type 4 and shigella sonnei to achieve a broad spectrum protection against shigellosis. adult mice were immunized ...201323684822
providencia alcalifaciens causes barrier dysfunction and apoptosis in tissue cell culture: potent role of lipopolysaccharides on diarrheagenicity.providencia alcalifaciens is a member of the enterobacteriaceae family that occasionally causes diarrheagenic illness in humans via the intake of contaminated foods. despite the epidemiological importance of p. alcalifaciens, little is known about its pathobiology. here we report that p. alcalifaciens causes barrier dysfunction in caco-2 cell monolayers and induces apoptosis in calf pulmonary artery endothelial cells. p. alcalifaciens infection caused a 30% reduction in transepithelial resistanc ...201323710559
a role for the ankyrin repeat containing protein ankrd17 in nod1- and nod2-mediated inflammatory responses.innate immune responses induced by the pattern-recognition receptors nod1 and nod2 play pivotal roles to combat infection and to instruct adaptive immunity. here we identify ankrd17 as a novel binding partner of nod2 and show that its n-terminal domain mediates nod2 binding. knock-down and overexpression analysis revealed that ankrd17 is functionally involved in nod2- and nod1-mediated responses in human myeloid and epithelial cells. in hela cells ankrd17 contributed to pro-inflammatory response ...201323711367
nanoparticle-based vaccine for mucosal protection against shigella flexneri in mice.shigellosis is one of the leading causes of diarrhea worldwide with more than 130 million cases annually. hence, the research of an effective vaccine is still a priority. unfortunately, a safe and efficacious vaccine is not available yet. we have previously demonstrated the capacity of outer membrane vesicles (omvs) to protect mice against an experimental infection with shigella flexneri. now, we present results on the capacity of this antigenic complex to confer a longer-term protection by oral ...201323727423
molecular cloning and biologically active production of ipad n-terminal region.shigella is known as pathogenic intestinal bacteria in high dispersion and pathogenic bacteria due to invasive plasmid antigen (ipa). so far, a number of ipa proteins have been studied to introduce a new candidate vaccine. here, for the first time, we examined whether the n-terminal region of ipad(72-162) could be a proper candidate for shigella vaccine. initially, the dna sequence coding n-terminal region was isolated by pcr from shigella dysenteriae type i and cloned into pet-28a expression ve ...201323731655
agglutinating secretory iga preserves intestinal epithelial cell integrity during apical infection by shigella flexneri.shigella flexneri, by invading intestinal epithelial cells (iecs) and inducing inflammatory responses of the colonic mucosa, causes bacillary dysentery. although m cells overlying peyer's patches are commonly considered the primary site of entry of s. flexneri, indirect evidence suggests that bacteria can also use iecs as a portal of entry to the lamina propria. passive delivery of secretory iga (siga), the major immunoglobulin secreted at mucosal surfaces, has been shown to protect rabbits from ...201323753631
characterization of intracellular growth regulator icgr by utilizing transcriptomics to identify mediators of pathogenesis in shigella flexneri.shigella species gram-negative bacteria which cause a diarrheal disease, known as shigellosis, by invading and destroying the colonic mucosa and inducing a robust inflammatory response. with no vaccine available, shigellosis annually kills over 600,000 children in developing countries. this study demonstrates the utility of combining high-throughput bioinformatic methods with in vitro and in vivo assays to provide new insights into pathogenesis. comparisons of in vivo and in vitro gene expressio ...201323753632
human single-chain urokinase is activated by the omptins pgte of salmonella enterica and pla of yersinia pestis despite mutations of active site residues.fibrinolysis is important in cell migration and tightly regulated by specific inhibitors and activators; of the latter, urokinase (upa) associates with enhancement of cell migration. active upa is formed through cleavage of the single-chain upa (scupa). the salmonella enterica strain 14028r cleaved human scupa at the peptide bond lys158-ile159, the site cleaved also by the physiological activator human plasmin. the cleavage led to activation of scupa, while no cleavage or activation were detecte ...201323763588
multidrug-resistant atypical variants of shigella flexneri in china.we identified 3 atypical shigella flexneri varieties in china, including 92 strains with multidrug resistance, distinct pulse types, and a novel sequence type. atypical varieties were prevalent mainly in developed regions, and 1 variant has become the dominant shigella spp. serotype in china. improved surveillance will help guide the prevention and control of shigellosis.201323763754
outer membrane protein a (ompa) from shigella flexneri 2a: a promising subunit vaccine candidate.shigellosis is the leading cause of childhood mortality and morbidity. despite many years of extensive research a practical vaccine is not yet available against the disease. recent studies illustrate that bacterial outer membrane proteins are budding target as vaccine antigen. outer membrane proteins a (ompa) are among the most immunodominant antigens in the outer membrane of gram negative bacteria and possess many characteristics desired of a vaccine candidate. we observe that ompa of shigella ...201323764536
bacteremia in the patients with acute pancreatitis as revealed by 16s ribosomal rna gene-based techniques.objectives:: to define the characteristic of bacteremia in the patients with acute pancreatitis and determine its possible association with the disease severity. design:: a prospective controlled study. setting:: icu of jinling hospital, china. patients:: a total of 48 patients with mild or severe acute pancreatitis were enrolled in this study. interventions:: none. measurements and main results:: samples of peripheral blood were collected from the patients at 4 or 5 and 9 or 10 days after acute ...201323764972
single cell measurements of vacuolar rupture caused by intracellular pathogens.shigella flexneri are pathogenic bacteria that invade host cells entering into an endocytic vacuole. subsequently, the rupture of this membrane-enclosed compartment allows bacteria to move within the cytosol, proliferate and further invade neighboring cells. mycobacterium tuberculosis is phagocytosed by immune cells, and has recently been shown to rupture phagosomal membrane in macrophages. we developed a robust assay for tracking phagosomal membrane disruption after host cell entry of shigella ...201323792688
expression of shigella flexneri ipab gene in tobacco.shigellosis is a leading cause of diarrhea in many developing countries and although the disease can be controlled and managed with antibiotics, the constant emergence of resistant species requiring ever newer antibacterial drugs make development of an effective vaccine necessary. the bacteria are highly contagious and since immunity to shigella is serotype-specific a multi-serotype vaccine is required for adequate protection. proteins encoded by shigella invasion plasmid, which are part of the ...201323799180
antimicrobial resistance and genetic characteristics of integron-carrier shigellae isolated in hungary (1998-2008).antimicrobial susceptibility, integron carriage, genetic relationship and presence of some important virulence genes of the integron-carrier strains of shigella sonnei (n = 230) and shigella flexneri (n = 22) isolated from stool samples of patients in hungary between 1998 and 2008 were investigated. sixty-seven per cent (168/252) of the strains were resistant to sulfamethoxazole/trimethoprim (sxt) followed by streptomycin (s, 47%), ampicillin (a, 32%) and tetracycline (tc, 28%). thirty-six per c ...201323800597
synthesis, biological evaluation and molecular docking studies of some pyrimidine derivatives.some novel pyrimidine-5-carbonitrile derivatives bearing various substituent have been synthesized. the structures of target compounds were confirmed by elemental analysis and spectral data. some selected members of the newly synthesized compounds were investigated for their cytotoxic potency against certain human tumor cell lines. five representative active anticancer compounds 6a, 6c, 6d, 17a and 18a were subjected to docking using moe program on the 3d structure of two enzymes, namely; thymid ...201323811090
systems-level overview of host protein phosphorylation during shigella flexneri infection revealed by phosphoproteomics.the enteroinvasive bacterium shigella flexneri invades the intestinal epithelium of humans. during infection, several injected effector proteins promote bacterial internalization, and interfere with multiple host cell responses. to obtain a systems-level overview of host signaling during infection, we analyzed the global dynamics of protein phosphorylation by liquid chromatography-tandem ms and identified several hundred of proteins undergoing a phosphorylation change during the first hours of i ...201323828894
medicinal potential of morella serata (lam.) killick (myricaceae) root extracts: biological and pharmacological activities.morella serata is a south african medicinal plant used in the treatment of microbial infections and to enhance male sexual performance. there is dearth of information in scientific literature on its efficacy and safety.201323829770
synthesis, spectroscopic, molecular orbital calculation, cytotoxic, molecular docking of dna binding and dna cleavage studies of transition metal complexes with n-benzylidene-n'-salicylidene-1,1-diaminopropane.eight mononuclear chromium(iii), manganese(ii), iron(iii), cobalt(ii), nickel(ii), copper(ii), zinc(ii) and cadmium(ii) complexes of schiff's base ligand were synthesized and determined by different physical techniques. the complexes are insoluble in common organic solvents but soluble in dmf and dmso. the measured molar conductance values in dmso indicate that the complexes are non-electrolytic in nature. all the eight metal complexes have been fully characterized with the help of elemental ana ...201323831943
protein expression, crystallization and preliminary x-ray crystallographic analysis of the isolated shigella flexneri vapc toxin.upon release from the stable complex formed with its antitoxin vapb, the toxin vapc (mvpt) of the gram-negative pathogen shigella flexneri is capable of globally down-regulating translation by specifically cleaving initiator trna(fmet) in the anticodon region. recombinant shigella flexneri vapc(d7a) harbouring an active-site mutation was overexpressed in escherichia coli, purified to homogeneity and crystallized by the vapour-diffusion technique. a preliminary x-ray crystallographic analysis sho ...201323832203
¹³c, ¹⁵n and ¹h backbone and side chain chemical shift assignment of acid-stress bacterial chaperone hdea at ph 6.hdea is a small chaperone found in the periplasm of several common pathogenic bacteria (escherichia coli, shigella flexneri and brucella abortus) which are the leading causes of dysentery worldwide, especially in developing countries. its job is to protect other periplasmic proteins from aggregating as the bacteria pass through the low ph environment of the human stomach on their way to infect the intestines. hdea is an inactive folded dimer at neutral ph, but becomes a disordered active monomer ...201423835624
self-adjuvanting bacterial vectors expressing pre-erythrocytic antigens induce sterile protection against malaria.genetically inactivated, gram-negative bacteria that express malaria vaccine candidates represent a promising novel self-adjuvanting vaccine approach. antigens expressed on particulate bacterial carriers not only target directly to antigen-presenting cells but also provide a strong danger signal thus circumventing the requirement for potent extraneous adjuvants. e. coli expressing malarial antigens resulted in the induction of either th1 or th2 biased responses that were dependent on both antige ...201323847617
bacteremia in patients with acute pancreatitis as revealed by 16s ribosomal rna gene-based techniques*.to define the characteristic of bacteremia in patients with acute pancreatitis and determine its possible association with the disease severity.201323863226
molecular mechanisms of cell-cell spread of intracellular bacterial pathogens.several bacterial pathogens, including listeria monocytogenes, shigella flexneri and rickettsia spp., have evolved mechanisms to actively spread within human tissues. spreading is initiated by the pathogen-induced recruitment of host filamentous (f)-actin. f-actin forms a tail behind the microbe, propelling it through the cytoplasm. the motile pathogen then encounters the host plasma membrane, forming a bacterium-containing protrusion that is engulfed by an adjacent cell. over the past two decad ...201323864553
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