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differential glycosylation of polar and lateral flagellins in aeromonas hydrophila ah-3.polar and lateral flagellin proteins from aeromonas hydrophila strain ah-3 (serotype o34) were found to be glycosylated with different carbohydrate moieties. the lateral flagellin was modified at three sites in o-linkage, with a single monosaccharide of 376 da, which we show to be a pseudaminic acid derivative. the polar flagellin was modified with a heterogeneous glycan, comprised of a heptasaccharide, linked through the same 376-da sugar to the protein backbone, also in o-linkage. in-frame del ...201222733809
towards a pathogenic escherichia coli detection platform using multiplex sybr®green real-time pcr methods and high resolution melting analysis.escherichia coli is a group of bacteria which has raised a lot of safety concerns in recent years. five major intestinal pathogenic groups have been recognized amongst which the verocytotoxin or shiga-toxin (stx1 and/or stx2) producing e. coli (vtec or stec respectively) have received a lot of attention recently. indeed, due to the high number of outbreaks related to vtec strains, the european food safety authority (efsa) has requested the monitoring of the "top-five" serogroups (o26, o103, o111 ...201222761753
entamoeba moshkovskii is associated with diarrhea in infants and causes diarrhea and colitis in mice.entamoeba moshkovskii is prevalent in developing countries and morphologically indistinguishable from pathogenic entamoeba histolytica and nonpathogenic entamoeba dispar. it is not known if e. moshkovskii is pathogenic.201222723640
multilocus sequence typing as a replacement for serotyping in salmonella enterica.salmonella enterica subspecies enterica is traditionally subdivided into serovars by serological and nutritional characteristics. we used multilocus sequence typing (mlst) to assign 4,257 isolates from 554 serovars to 1092 sequence types (sts). the majority of the isolates and many sts were grouped into 138 genetically closely related clusters called eburstgroups (ebgs). many ebgs correspond to a serovar, for example most typhimurium are in ebg1 and most enteritidis are in ebg4, but many ebgs co ...201222737074
trif mobilizes unique primary defense against gram-negative bacteria in intestinal interface.the gastrointestinal tract is the largest mucosal surface in our body. it houses diverse microorganisms that collectively form the commensal microbial community. the security of this community is kept by host-microbial interactions and is violated by foreign pathogens that induce local as well as systemic pathology. in most cases, gastrointestinal infections are caused by gram-negative enteropathogens, which trigger host immune responses through the tlr4 signaling pathways. although trif is one ...201222713267
network compression as a quality measure for protein interaction networks.with the advent of large-scale protein interaction studies, there is much debate about data quality. can different noise levels in the measurements be assessed by analyzing network structure? because proteomic regulation is inherently co-operative, modular and redundant, it is inherently compressible when represented as a network. here we propose that network compression can be used to compare false positive and false negative noise levels in protein interaction networks. we validate this hypoth ...201222719828
autoimmunity, dendritic cells and relevance for parkinson's disease.innate and adaptive immune responses in neurodegenerative diseases have become recently a focus of research and discussions. parkinson's disease (pd) is a neurodegenerative disorder without known etiopathogenesis. the past decade has generated evidence for an involvement of the immune system in pd pathogenesis. both inflammatory and autoimmune mechanisms have been recognized and studies have emphasized the role of activated microglia and t-cell infiltration. in this short review, we focus on den ...201222699458
autoimmunity, dendritic cells and relevance for parkinson's disease.innate and adaptive immune responses in neurodegenerative diseases have become recently a focus of research and discussions. parkinson's disease (pd) is a neurodegenerative disorder without known etiopathogenesis. the past decade has generated evidence for an involvement of the immune system in pd pathogenesis. both inflammatory and autoimmune mechanisms have been recognized and studies have emphasized the role of activated microglia and t-cell infiltration. in this short review, we focus on den ...201222699458
16s rrna gene pyrosequencing reveals bacterial dysbiosis in the duodenum of dogs with idiopathic inflammatory bowel disease.canine idiopathic inflammatory bowel disease (ibd) is believed to be caused by a complex interaction of genetic, immunologic, and microbial factors. while mucosa-associated bacteria have been implicated in the pathogenesis of canine ibd, detailed studies investigating the enteric microbiota using deep sequencing techniques are lacking. the objective of this study was to evaluate mucosa-adherent microbiota in the duodenum of dogs with spontaneous idiopathic ibd using 16 s rrna gene pyrosequencing ...201222720094
indomethacin-induced translocation of bacteria across enteric epithelia is reactive oxygen species-dependent and reduced by vitamin c.the enteric epithelium must absorb nutrients and water and act as a barrier to the entry of luminal material into the body; this barrier function is a key component of innate immunity. nonsteroidal anti-inflammatory drug (nsaid)-induced enteropathy occurs via inhibition of prostaglandin synthesis and perturbed epithelial mitochondrial activity. here, the direct effect of nsaids [indomethacin, piroxicam (cyclooxygenase 1 and 2 inhibitors), and sc-560 (a cyclooxygenase 1 inhibitor)] on the barrier ...201222700821
serum sickness following rabbit anti-thymocyte globulin for acute vascular renal allograft rejection.a simultaneous pancreas-kidney transplant recipient developed serum sickness manifesting with severe upper limb allodynia, arthralgia and myalgia 17 days following rabbit anti-thymocyte globulin (ratg) infusion for biopsy-proven vascular rejection. rapid resolution of symptoms followed treatment with high-dose glucocorticoids. ratg is increasingly favoured over equine atg in solid-organ transplantation, and although ratg has a superior safety profile, it is important to maintain a high index of ...201225874092
structure, function and diversity of the healthy human microbiome.studies of the human microbiome have revealed that even healthy individuals differ remarkably in the microbes that occupy habitats such as the gut, skin and vagina. much of this diversity remains unexplained, although diet, environment, host genetics and early microbial exposure have all been implicated. accordingly, to characterize the ecology of human-associated microbial communities, the human microbiome project has analysed the largest cohort and set of distinct, clinically relevant body hab ...201222699609
the structural biology of enzymes involved in natural product glycosylation.the glycosylation of microbial natural products often dramatically influences the biological and/or pharmacological activities of the parental metabolite. over the past decade, crystal structures of several enzymes involved in the biosynthesis and attachment of novel sugars found appended to natural products have emerged. in many cases, these studies have paved the way to a better understanding of the corresponding enzyme mechanism of action and have served as a starting point for engineering va ...201222688446
phage-mediated acquisition of a type iii secreted effector protein boosts growth of salmonella by nitrate respiration.information on how emerging pathogens can invade and persist and spread within host populations remains sparse. in the 1980s, a multidrug-resistant salmonella enterica serotype typhimurium clone lysogenized by a bacteriophage carrying the sope virulence gene caused an epidemic among cattle and humans in europe. here we show that phage-mediated horizontal transfer of the sope gene enhances the production of host-derived nitrate, an energetically highly valuable electron acceptor, in a mouse colit ...201222691391
structural dynamics of the aminoacylation and proofreading functional cycle of bacterial leucyl-trna synthetase.leucyl-trna synthetase (leurs) produces error-free leucyl-trna(leu) by coordinating translocation of the 3' end of (mis-)charged trnas from its synthetic site to a separate proofreading site for editing. here we report cocrystal structures of the escherichia coli leurs-trna(leu) complex in the aminoacylation or editing conformations, showing that translocation involves correlated rotations of four flexibly linked leurs domains. this pivots the trna to guide its charged 3' end from the closed ami ...201222683997
acinetobacter calcoaceticus-baumannii complex strains induce caspase-dependent and caspase-independent death of human epithelial cells.we investigated interactions of human isolates of acinetobacter calcoaceticus-baumannii complex strains with epithelial cells. the results showed that bacterial contact with the cells as well as adhesion and invasion were required for induction of cytotoxicity. the infected cells revealed hallmarks of apoptosis characterized by cell shrinking, condensed chromatin, and internucleosomal fragmentation of nuclear dna. the highest apoptotic index was observed for 4 of 10 a. calcoaceticus and 4 of 7 a ...201222684803
genomering: alignment visualization based on supergenome coordinates.the number of completely sequenced genomes is continuously rising, allowing for comparative analyses of genomic variation. such analyses are often based on whole-genome alignments to elucidate structural differences arising from insertions, deletions or from rearrangement events. computational tools that can visualize genome alignments in a meaningful manner are needed to help researchers gain new insights into the underlying data. such visualizations typically are either realized in a linear fa ...201222689781
antimicrobial-resistant bacteria: an unrecognized work-related risk in food animal production.the occupations involved in food animal production have long been recognized to carry significant health risks for workers, with special attention to injuries. however, risk of pathogen exposure in these occupations has been less extensively considered. pathogens are a food safety issue and are known to be present throughout the food animal production chain. workers employed at farms and slaughterhouses are at risk of pathogen exposure and bacterial infections. the industrialization of animal fa ...201222993711
identification of a general o-linked protein glycosylation system in acinetobacter baumannii and its role in virulence and biofilm formation.acinetobacter baumannii is an emerging cause of nosocomial infections. the isolation of strains resistant to multiple antibiotics is increasing at alarming rates. although a. baumannii is considered as one of the more threatening "superbugs" for our healthcare system, little is known about the factors contributing to its pathogenesis. in this work we show that a. baumannii atcc 17978 possesses an o-glycosylation system responsible for the glycosylation of multiple proteins. 2d-dige and mass spec ...201222685409
microbiota, disease, and back to health: a metastable journey.alterations in the composition of the commensal microbiota have been observed in many complex diseases. understanding the basis for these changes, how they relate to disease risk or activity, and the mechanisms by which the symbiotic state of colonization resistance and host homeostasis is restored is critical for future therapies aimed at manipulating the microbiota.201222674557
multiple post-translational modifications affect heterologous protein synthesis.post-translational modifications (ptms) are required for proper folding of many proteins. the low capacity for ptms hinders the production of heterologous proteins in the widely used prokaryotic systems of protein synthesis. until now, a systematic and comprehensive study concerning the specific effects of individual ptms on heterologous protein synthesis has not been presented. to address this issue, we expressed 1488 human proteins and their domains in a bacterial cell-free system, and we exam ...201222674579
beneficial effect of bupleurum polysaccharides on autoimmune-prone mrl-lpr mice.systemic lupus erythematosus (sle) is a chronic systemic autoimmune disease leading to inflammatory tissue damage in multiple organs. the crude polysaccharides (bps) isolated from the roots of bupleurum smithii var. parvifolium have anticomplementary activity and immunomodulatory functions on macrophages. to study its potential benefit on sle, we examined effects of bps on mrl-lpr mice, which have similar disease features to human sle. mrl-lpr mice were treated orally with bps 15, 30, or 60 mg k ...201222701502
investigation of antibacterial, acid and bile tolerance properties of lactobacilli isolated from koozeh cheese.lactobacillus strains are a major part of the probiotics, microflora of the intestine and of fermented dairy products, and are found in a variety of environments. the aim of this study was to find out the ability of bile and acid tolerance and antibacterial properties of the twenty eight isolates of three group lactobacilli namely lactobacillus plantarum, lactobacillus casei and lactobacillus delbruki. for this purpose twenty eight different lactobacillus strains that isolated from koozeh cheese ...201225610566
clinical importance and representation of toxigenic and non-toxigenic clostridium difficile cultivated from stool samples of hospitalized patients.the aim of this study was to fortify the clinical importance and representation of toxigenic and non-toxigenic clostridium difficile isolated from stool samples of hospitalized patients. this survey included 80 hospitalized patients with diarrhea and positive findings of clostridium difficile in stool samples, and 100 hospitalized patients with formed stool as a control group. bacteriological examination of a stool samples was conducted using standard microbiological methods. stool sample were i ...201224031820
activity of disinfectants against foodborne pathogens in suspension and adhered to stainless steel surfaces.the purpose of this study was to investigate and compare the efficacy of various disinfectants on planktonic cells and biofilm cells of listeria monocytogenes, staphylococcus aureus and escherichia coli. numbers of viable biofilm cells decreased after treatment with all tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite). sodium hypochlorite was the most effective disinfectant against biofilm cells, while biguanide was the least effecti ...201224031935
oxygen limitation favors the production of protein with antimicrobial activity in pseudoalteromonas sp.this study examined the effect of dissolved oxygen concentration on the production of biomass and metabolites with antimicrobial activity of pseudoalteromonas sp cultured at 0, 150, 250, or 450 revolutions per minute (rev. min(-1)). dissolved oxygen (d.o) was monitored during the fermentation process, biomass was quantified by dry weight, and antimicrobial activity was assessed using the disk diffusion method. the bacterium pseudoalteromonas reached similar concentration of biomass under all exp ...201224031945
identification of a putative glycosyltransferase responsible for the transfer of pseudaminic acid onto the polar flagellin of aeromonas caviae sch3n.motility in aeromonas caviae, in a liquid environment (in broth culture), is mediated by a single polar flagellum encoded by the fla genes. the polar flagellum filament of a. caviae is composed of two flagellin subunits, flaa and flab, which undergo o-linked glycosylation with six to eight pseudaminic acid glycans linked to serine and threonine residues in their central region. the flm genetic locus in a. caviae is required for flagellin glycosylation and the addition of pseudaminic acid (pse) o ...201222950021
the alternative translational profile that underlies the immune-evasive state of persistence in chlamydiaceae exploits differential tryptophan contents of the protein repertoire.one form of immune evasion is a developmental state called "persistence" whereby chlamydial pathogens respond to the host-mediated withdrawal of l-tryptophan (trp). a sophisticated survival mode of reversible quiescence is implemented. a mechanism has evolved which suppresses gene products necessary for rapid pathogen proliferation but allows expression of gene products that underlie the morphological and developmental characteristics of persistence. this switch from one translational profile to ...201222688818
alterations in the porcine colon microbiota induced by the gastrointestinal nematode trichuris suis.helminth parasites ensure their survival by regulating host immunity through mechanisms that dampen inflammation. these properties have recently been exploited therapeutically to treat human diseases. the biocomplexity of the intestinal lumen suggests that interactions between the parasite and the intestinal microbiota would also influence inflammation. in this study, we characterized the microbiota in the porcine proximal colon in response to trichuris suis (whipworm) infection using 16s rrna g ...201222493085
development and evaluation of a quantitative pcr assay targeting sandhill crane (grus canadensis) fecal pollution.while the microbial water quality in the platte river is seasonally impacted by excreta from migrating cranes, there are no methods available to study crane fecal contamination. here we characterized microbial populations in crane feces using phylogenetic analysis of 16s rrna gene fecal clone libraries. using these sequences, a novel crane quantitative pcr (crane1) assay was developed, and its applicability as a microbial source tracking (mst) assay was evaluated by determining its host specific ...201222492437
zoonotic agents in small ruminants kept on city farms in southern germany.sheep and goats are popular examples of livestock kept on city farms. in these settings, close contacts between humans and animals frequently occur. although it is widely accepted that small ruminants can carry numerous zoonotic agents, it is unknown which of these agents actually occur in sheep and goats on city farms in germany. we sampled feces and nasal liquid of 48 animals (28 goats, 20 sheep) distributed in 7 city farms and on one activity playground in southern germany. we found that 100% ...201222447607
rational design and directed evolution of a bacterial-type glutaminyl-trna synthetase precursor.protein biosynthesis requires aminoacyl-transfer rna (trna) synthetases to provide aminoacyl-trna substrates for the ribosome. most bacteria and all archaea lack a glutaminyl-trna synthetase (glnrs); instead, gln-trna(gln) is produced via an indirect pathway: a glutamyl-trna synthetase (glurs) first attaches glutamate (glu) to trna(gln), and an amidotransferase converts glu-trna(gln) to gln-trna(gln). the human pathogen helicobacter pylori encodes two glurs enzymes, with glurs2 specifically amin ...201222661575
experimental evolution of legionella pneumophila in mouse macrophages leads to strains with altered determinants of environmental survival.the gram-negative bacterium, legionella pneumophila, is a protozoan parasite and accidental intracellular pathogen of humans. we propose a model in which cycling through multiple protozoan hosts in the environment holds l. pneumophila in a state of evolutionary stasis as a broad host-range pathogen. using an experimental evolution approach, we tested this hypothesis by restricting l. pneumophila to growth within mouse macrophages for hundreds of generations. whole-genome resequencing and high-th ...201222693450
simulation of molecular data under diverse evolutionary scenarios. 201222693434
risk of inflammatory bowel disease following a diagnosis of irritable bowel syndrome.irritable bowel syndrome (ibs) and inflammatory bowel disease (ibd) symptoms often overlap. in some ibs cases there are subtle inflammatory changes similar to the immune-mediated pathophysiology of ibd, and the risk of both increases after infectious gastroenteritis (ige).201222639930
two plant bacteria, s. meliloti and ca. liberibacter asiaticus, share functional znuabc homologues that encode for a high affinity zinc uptake system.the znu system, encoded for by znuabc, can be found in multiple genera of bacteria and has been shown to be responsible for the import of zinc under low zinc conditions. although this high-affinity uptake system is known to be important for both growth and/or pathogenesis in bacteria, it has not been functionally characterized in a plant-associated bacterium. a single homologue of this system has been identified in the plant endosymbiont, sinorhizobium meliloti, while two homologous systems were ...201222655039
fine specificity and cross-reactions of monoclonal antibodies to group b streptococcal capsular polysaccharide type iii.group b streptococcus (gbs) is a major cause of neonatal sepsis and meningitis. despite aggressive campaigns using antenatal prophylactic antibiotic therapy, infections continue. developing an effective maternal vaccine is a public health priority. antibody (ab) to the capsular polysaccharide (cps) is considered the dominant "protective" immune mediator. here we study the fine specificity and potential host reactivity of a panel of well-characterized murine monoclonal abs against the type iii cp ...201222634296
quantification of the relative roles of niche and neutral processes in structuring gastrointestinal microbiomes.the theoretical description of the forces that shape ecological communities focuses around two classes of models. in niche theory, deterministic interactions between species, individuals, and the environment are considered the dominant factor, whereas in neutral theory, stochastic forces, such as demographic noise, speciation, and immigration, are dominant. species abundance distributions predicted by the two classes of theory are difficult to distinguish empirically, making it problematic to de ...201222615407
why do bacteria use so many enzymes to scavenge hydrogen peroxide?hydrogen peroxide (h(2)o(2)) is continuously formed by the autoxidation of redox enzymes in aerobic cells, and it also enters from the environment, where it can be generated both by chemical processes and by the deliberate actions of competing organisms. because h(2)o(2) is acutely toxic, bacteria elaborate scavenging enzymes to keep its intracellular concentration at nanomolar levels. mutants that lack such enzymes grow poorly, suffer from high rates of mutagenesis, or even die. in order to und ...201222609271
the incidence and risk of celiac disease in a healthy us adult population.celiac disease (cd) is an increasingly common disease that may affect as many as 1% of the north american population. recent population-based data suggest a substantial increase in the prevalence of cd over the last several decades. several factors are hypothesized as possible disease triggers including intercurrent illnesses, such as gastroenteritis, surgeries, and trauma. we used the active duty us military, a unique healthy worker population with essentially complete medical diagnostic coding ...201222584218
lipopolysaccharides: from erinyes to charites.following the discovery of endotoxins by richard pfeiffer, such bacterial product was associated to many severe disorders produced by an overwhelming inflammatory response and often resulting in endotoxic shock and multiple organ failure. however, recent clinical and basic sciences investigations claimed some beneficial roles of typical as well as atypical endotoxins. the aim of this paper is to focus on recent data supporting a beneficial activity of both typical and atypical endotoxins. such n ...201222665953
exoribonucleases as modulators of virulence in pathogenic bacteria. 201222919656
age of the association between helicobacter pylori and man.when modern humans left africa ca. 60,000 years ago (60 kya), they were already infected with helicobacter pylori, and these bacteria have subsequently diversified in parallel with their human hosts. but how long were humans infected by h. pylori prior to the out-of-africa event? did this co-evolution predate the emergence of modern humans, spanning the species divide? to answer these questions, we investigated the diversity of h. pylori in africa, where both humans and h. pylori originated. thr ...201222589724
genes important for catalase activity in enterococcus faecalis.little in general is known about how heme proteins are assembled from their constituents in cells. the gram-positive bacterium enterococcus faecalis cannot synthesize heme and does not depend on it for growth. however, when supplied with heme in the growth medium the cells can synthesize two heme proteins; catalase (kata) and cytochrome bd (cydab). to identify novel factors important for catalase biogenesis libraries of e. faecalis gene insertion mutants were generated using two different types ...201222590595
chemo-enzymatic modification of poly-n-acetyllactosamine (lacnac) oligomers and n,n-diacetyllactosamine (lacdinac) based on galactose oxidase treatment.the importance of glycans in biological systems is highlighted by their various functions in physiological and pathological processes. many glycan epitopes on glycoproteins and glycolipids are based on n-acetyllactosamine units (lacnac; galβ1,4glcnac) and often present on extended poly-lacnac glycans ([galβ1,4glcnac](n)). poly-lacnac itself has been identified as a binding motif of galectins, an important class of lectins with functions in immune response and tumorigenesis. therefore, the synthe ...201223015818
prediction and identification of sequences coding for orphan enzymes using genomic and metagenomic neighbours.despite the current wealth of sequencing data, one-third of all biochemically characterized metabolic enzymes lack a corresponding gene or protein sequence, and as such can be considered orphan enzymes. they represent a major gap between our molecular and biochemical knowledge, and consequently are not amenable to modern systemic analyses. as 555 of these orphan enzymes have metabolic pathway neighbours, we developed a global framework that utilizes the pathway and (meta)genomic neighbour inform ...201222569339
bone marrow involvement in a patient with alpha heavychain disease: response to tetracycline treatment.a 28-year-old man from east mediterranean area admitted with abdominal pain, weight loss and diarrhea. barium x-ray studies showed segmentation, dilatation of bowel loops, mucosal folds thickening and delayed intestinal transit. histological examination of biopsy specimens revealed villous atrophy and plasmacytic infiltration limited to mucosa and submucosa. computed tomography showed multiple lymphadenopathy in the abdomen. serum protein electropheresis and immunoelectropheresis indicated eleva ...201222708049
high adherence is necessary to realize health gains from water quality interventions.safe drinking water is critical for health. household water treatment (hwt) has been recommended for improving access to potable water where existing sources are unsafe. reports of low adherence to hwt may limit the usefulness of this approach, however.201222586491
the predominance of type i oligosaccharides is a feature specific to human breast milk.human milk and colostrum contain ∼12-13 g/l and ∼22-24 g/l of oligosaccharides, respectively. the chemical structures of >100 human milk oligosaccharides (hmo) have been characterized to date. we determined the concentrations of 10 neutral and 9 acidic colostrum hmo collected during the first 3 d of lactation by using reverse phase hplc after derivatization with 2-aminopyridine or 1-methyl-3-phenyl-5-pyrazolon. the predominant oligosaccharides were fuc(α1-2)gal(β1-4glc (2'-fl), fuc(α1-2)gal(β1-3 ...201222585927
profiles of human milk oligosaccharides and production of some human milk oligosaccharides in transgenic animals.during the decade of the 1990s and the first years of the current century, our group embarked on a project to study and synthesize human milk oligosaccharides. this report describes 2 unexpected collateral observations from that endeavor. the first observation was the detection and confirmation of 2 rare neutral human milk oligosaccharides profiles that were uncovered while assessing oligosaccharide content in hundreds of samples of human milk. one of these lacked fucosylated structures altogeth ...201222585925
human milk oligosaccharides and lewis blood group: individual high-throughput sample profiling to enhance conclusions from functional studies.human milk oligosaccharides (hmo) are discussed to play a crucial role in an infant's development. lewis blood group epitopes, in particular, seem to remarkably contribute to the beneficial effects of hmo. in this regard, large-scale functional human studies could provide evidence of the variety of results from in vitro investigations, although increasing the amount and complexity of sample and data handling. therefore, reliable screening approaches are needed. to predict the oligosaccharide pat ...201222585923
advances in analysis of human milk oligosaccharides.oligosaccharides in human milk strongly influence the composition of the gut microflora of neonates. because it is now clear that the microflora play important roles in the development of the infant immune system, human milk oligosaccharides (hmo) are studied frequently. milk samples contain complex mixtures of hmo, usually comprising several isomeric structures that can be either linear or branched. traditionally, hmo profiling was performed using hplc with fluorescence or uv detection. by usin ...201222585919
structure-function relationships of human milk oligosaccharides.human milk contains more than a hundred structurally distinct oligosaccharides. in this review, we provide examples of how the structural characteristics of these human milk oligosaccharides (hmo) determine functionality. specific α1-2-fucosylated hmo have been shown to serve as antiadhesive antimicrobials to protect the breast-fed infant against infections with campylobacter jejuni, one of the most common causes of bacterial diarrhea. in contrast, α1-2-fucosylation may abolish the beneficial ef ...201222585916
the lipopolysaccharide from capnocytophaga canimorsus reveals an unexpected role of the core-oligosaccharide in md-2 binding.capnocytophaga canimorsus is a usual member of dog's mouths flora that causes rare but dramatic human infections after dog bites. we determined the structure of c. canimorsus lipid a. the main features are that it is penta-acylated and composed of a "hybrid backbone" lacking the 4' phosphate and having a 1 phosphoethanolamine (p-etn) at 2-amino-2-deoxy-d-glucose (glcn). c. canimorsus lps was 100 fold less endotoxic than escherichia coli lps. surprisingly, c. canimorsus lipid a was 20,000 fold le ...201222570611
passage of campylobacter jejuni through the chicken reservoir or mice promotes phase variation in contingency genes cj0045 and cj0170 that strongly associates with colonization and disease in a mouse model.human illness due to camplyobacter jejuni infection is closely associated with consumption of poultry products. we previously demonstrated a 50 % shift in allele frequency (phase variation) in contingency gene cj1139 (wlan) during passage of c. jejuni nctc11168 populations through ross 308 broiler chickens. we hypothesized that phase variation in contingency genes during chicken passage could promote subsequent colonization and disease in humans. to test this hypothesis, we passaged c. jejuni st ...201222343355
persistent helicobacter pullorum colonization in c57bl/6ntac mice: a new mouse model for an emerging zoonosis.helicobacter pullorum, an enterohepatic helicobacter species, is associated with gastroenteritis and hepatobiliary disease in humans and chickens. recently, a novel h. pullorum outbreak in barrier-maintained rats and mice was described. in this study, persistence of infection and serological responses were further evaluated in h. pullorum-infected female c57bl/6ntac and c3h/hentac mice obtained from the barrier outbreak. c57bl/6ntac mice (n=36) aged 10-58 weeks were confirmed to be chronically i ...201222301616
a framework for assessing the concordance of molecular typing methods and the true strain phylogeny of campylobacter jejuni and c. coli using draft genome sequence data.tracking of sources of sporadic cases of campylobacteriosis remains challenging, as commonly used molecular typing methods have limited ability to unambiguously link genetically related strains. genomics has become increasingly prominent in the public health response to enteric pathogens as methods enable characterization of pathogens at an unprecedented level of resolution. however, the cost of sequencing and expertise required for bioinformatic analyses remains prohibitive, and these comprehen ...201222919648
prediction and comparison of salmonella-human and salmonella-arabidopsis interactomes.salmonellosis caused by salmonella bacteria is a food-borne disease and a worldwide health threat causing millions of infections and thousands of deaths every year. this pathogen infects an unusually broad range of host organisms including human and plants. a better understanding of the mechanisms of communication between salmonella and its hosts requires identifying the interactions between salmonella and host proteins. protein-protein interactions (ppis) are the fundamental building blocks of ...201222589098
antimicrobial effect of diallyl sulphide on campylobacter jejuni biofilms.bacterial biofilms pose significant food safety risks because of their attachment to fomites and food surfaces, including fresh produce surfaces. the purpose of this study was to systematically investigate the activity of selected antimicrobials on campylobacter jejuni biofilms.201222550133
canadian digestive health foundation public impact series 3: irritable bowel syndrome in canada. incidence, prevalence, and direct and indirect economic impact.the canadian digestive health foundation initiated a scientific program to assess the incidence, prevalence, mortality and economic impact of digestive disorders across canada in 2009. the current article presents the updated findings from the study concerning irritable bowel syndrome.201222590697
increase in campylobacter jejuni invasion of intestinal epithelial cells under low-oxygen coculture conditions that reflect the in vivo environment.campylobacter jejuni infection often results in bloody, inflammatory diarrhea, indicating bacterial disruption and invasion of the intestinal epithelium. while c. jejuni infection can be reproduced in vitro using intestinal epithelial cell (iec) lines, low numbers of bacteria invading iecs do not reflect these clinical symptoms. performing in vitro assays under atmospheric oxygen conditions neither is optimal for microaerophilic c. jejuni nor reflects the low-oxygen environment of the intestinal ...201222354027
identification of genes involved in the acetamidino group modification of the flagellin n-linked glycan of methanococcus maripaludis.n-linked glycosylation of protein is a posttranslational modification found in all three domains of life. the flagellin proteins of the archaeon methanococcus maripaludis are known to be modified with an n-linked tetrasaccharide consisting of n-acetylgalactosamine (galnac), a diacetylated glucuronic acid (glcnac3nac), an acetylated and acetamidino-modified mannuronic acid with a substituted threonine group (mannac3nama6thr), and a novel terminal sugar residue [(5s)-2-acetamido-2,4-dideoxy-5-o-me ...201222408155
identification and characterization of a lipopolysaccharide α,2,3-sialyltransferase from the human pathogen helicobacter bizzozeronii.terminal sialic acid in the lipopolysaccharides (lpss) of mucosal pathogens is an important virulence factor. here we report the characterization of a helicobacter sialyltransferase involved in the biosynthesis of sialylated lps in helicobacter bizzozeronii, the only non-pylori gastric helicobacter species isolated from humans thus far. starting from the genome sequences of canine and human strains, we identified potential sialyltransferases downstream of three genes involved in the biosynthesis ...201222408169
epidemiology of klebsiella oxytoca-associated diarrhea detected by simmons citrate agar supplemented with inositol, tryptophan, and bile salts.we studied the clinical and epidemiological characteristics of klebsiella oxytoca-associated diarrhea in hospitalized patients in hong kong. between 1 november 2009 and 30 april 2011, all inositol-fermenting colonies found on simmons citrate agar supplemented with inositol, tryptophan, and bile salts (scitb agar) used for the culturing of diarrheal stool samples were screened by a spot indole test for k. oxytoca. the overall sensitivity of scitb agar plus the spot indole test (93.3%) for the det ...201222357507
characterization of campylobacter jejuni racrs reveals roles in the heat shock response, motility, and maintenance of cell length homogeneity.campylobacter jejuni commensally colonizes the cecum of birds. the racr (reduced ability to colonize) response regulator was previously shown to be important in avian colonization. to explore the means by which racr and its cognate sensor kinase racs may modulate c. jejuni physiology and colonization, δracr and δracs mutations were constructed in the invasive, virulent strain 81-176, and extensive phenotypic analyses were undertaken. both the δracr and δracs mutants exhibited a ~100-fold defect ...201222343300
identification of potential type iii secretion proteins via heterologous expression of vibrio parahaemolyticus dna.we employed a heterologous secretion assay to identify proteins potentially secreted by type iii secretion systems (t3sss) in vibrio parahaemolyticus. n-terminal sequences from 32 proteins within t3ss genomic islands and seven proteins from elsewhere in the chromosome included proteins that were recognized for export by the yersinia enterocolitica flagellar t3ss.201222389365
cytoplasmic ph response to acid stress in individual cells of escherichia coli and bacillus subtilis observed by fluorescence ratio imaging microscopy.the ability of escherichia coli and bacillus subtilis to regulate their cytoplasmic ph is well studied in cell suspensions but is poorly understood in individual adherent cells and biofilms. we observed the cytoplasmic ph of individual cells using ratiometric phluorin. a standard curve equating the fluorescence ratio with ph was obtained by perfusion at a range of external ph 5.0 to 9.0, with uncouplers that collapse the transmembrane ph difference. adherent cells were acid stressed by switching ...201222427503
intestinal microbiota shifts towards elevated commensal escherichia coli loads abrogate colonization resistance against campylobacter jejuni in mice.the zoonotic pathogen campylobacter jejuni is a leading cause of bacterial foodborne enterocolitis in humans worldwide. the understanding of immunopathology underlying human campylobacteriosis is hampered by the fact that mice display strong colonization resistance against the pathogen due to their host specific gut microbiota composition.201222563475
human gastric mucins differently regulate helicobacter pylori proliferation, gene expression and interactions with host cells.helicobacter pylori colonizes the mucus niche of the gastric mucosa and is a risk factor for gastritis, ulcers and cancer. the main components of the mucus layer are heavily glycosylated mucins, to which h. pylori can adhere. mucin glycosylation differs between individuals and changes during disease. here we have examined the h. pylori response to purified mucins from a range of tumor and normal human gastric tissue samples. our results demonstrate that mucins from different individuals differ i ...201222563496
campylobacteremia in stage iv gliosarcoma with bevacizumab treatment.primary campylobacter enteritis with secondary bacteremia was diagnosed in an immunocompromised patient with stage iv gliosarcoma. she developed mild diarrhea followed by systemic symptoms with transient generalized weakness and fever. she was treated with azithromycin and had a full recovery and without relapse through 2 months of follow-up. her diagnosis was confirmed by a positive stool culture for campylobacter sp. and blood culture for campylobacter jejuni/coli.201223882353
whole cell biosynthesis of a functional oligosaccharide, 2'-fucosyllactose, using engineered escherichia coli.2'-fucosyllactose (2-fl) is a functional oligosaccharide present in human milk which protects against the infection of enteric pathogens. because 2-fl can be synthesized through the enzymatic fucosylation of lactose with guanosine 5'-diphosphate (gdp)-l-fucose by α-1,2-fucosyltransferase (fuct2), an 2-fl producing escherichia coli can be constructed through overexpressing genes coding for endogenous gdp- l-fucose biosynthetic enzymes and heterologous fucosyltransferase.201222545760
expression of colonization factor cs5 of enterotoxigenic escherichia coli (etec) is enhanced in vivo and by the bile component na glycocholate hydrate.enterotoxigenic escherichia coli (etec) is an important cause of acute watery diarrhoea in developing countries. colonization factors (cfs) on the bacterial surface mediate adhesion to the small intestinal epithelium. two of the most common cfs worldwide are coli surface antigens 5 and 6 (cs5, cs6). in this study we investigated the expression of cs5 and cs6 in vivo, and the effects of bile and sodium bicarbonate, present in the human gut, on the expression of cs5. five cs5+cs6 etec isolates fro ...201222563407
campylobacter jejuni lipooligosaccharide sialylation, phosphorylation, and amide/ester linkage modifications fine-tune human toll-like receptor 4 activation.campylobacter jejuni is a leading cause of acute gastroenteritis. c. jejuni lipooligosaccharide (los) is a potent activator of toll-like receptor (tlr) 4-mediated innate immunity. structural variations of the los have been previously reported in the oligosaccharide (os) moiety, the disaccharide lipid a (la) backbone, and the phosphorylation of the la. here, we studied los structural variation between c. jejuni strains associated with different ecological sources and analyzed their ability to act ...201223629657
campylobacter jejuni lipooligosaccharide sialylation, phosphorylation, and amide/ester linkage modifications fine-tune human toll-like receptor 4 activation.campylobacter jejuni is a leading cause of acute gastroenteritis. c. jejuni lipooligosaccharide (los) is a potent activator of toll-like receptor (tlr) 4-mediated innate immunity. structural variations of the los have been previously reported in the oligosaccharide (os) moiety, the disaccharide lipid a (la) backbone, and the phosphorylation of the la. here, we studied los structural variation between c. jejuni strains associated with different ecological sources and analyzed their ability to act ...201223629657
functional metagenomics reveals novel salt tolerance loci from the human gut microbiome.metagenomics is a powerful tool that allows for the culture-independent analysis of complex microbial communities. one of the most complex and dense microbial ecosystems known is that of the human distal colon, with cell densities reaching up to 10(12) per gram of faeces. with the majority of species as yet uncultured, there are an enormous number of novel genes awaiting discovery. in the current study, we conducted a functional screen of a metagenomic library of the human gut microbiota for pot ...201222534607
rapid paracellular transmigration of campylobacter jejuni across polarized epithelial cells without affecting ter: role of proteolytic-active htra cleaving e-cadherin but not fibronectin.campylobacter jejuni is one of the most important bacterial pathogens causing food-borne illness worldwide. crossing the intestinal epithelial barrier and host cell entry by c. jejuni is considered the primary reason of damage to the intestinal tissue, but the molecular mechanisms as well as major bacterial and host cell factors involved in this process are still widely unclear.201222534208
methyl eugenol: its occurrence, distribution, and role in nature, especially in relation to insect behavior and pollination.this review discusses the occurrence and distribution (within a plant) of methyl eugenol in different plant species (> 450) from 80 families spanning many plant orders, as well as various roles this chemical plays in nature, especially in the interactions between tephritid fruit flies and plants.201222963669
the role of bacteria in the pathogenesis of ulcerative colitis.factors implicated in the pathophysiology of ulcerative colitis (uc) are an abnormal immune response, defect in intestinal epithelial barrier function, and gut microbiota. currently, it is unclear whether specific bacterial strains are responsible for the induction of intestinal inflammation, but increased bacterial tissue invasion has been described in affected uc patients. further, a quantitative and qualitative microbial imbalance in uc, defined as dysbiosis, has been characterized by an incr ...201222619714
antimicrobial activities of isothiocyanates against campylobacter jejuni isolates.food-borne human infection with campylobacter jejuni is a medical concern in both industrialized and developing countries. efficient eradication of c. jejuni reservoirs within live animals and processed foods is limited by the development of antimicrobial resistances and by practical problems related to the use of conventional antibiotics in food processes. we have investigated the bacteriostatic and bactericidal activities of two phytochemicals, allyl-isothiocyanate (aitc), and benzyl isothiocy ...201222919644
evaluation of the clinical value of elisa based on mpt64 antibody aptamer for serological diagnosis of pulmonary tuberculosis.presently, tuberculosis (tb) poses a global threat to human health. the development of reliable laboratory tools is vital to the diagnosis and treatment of tb. mpt64, a protein secreted by mycobacterium tuberculosis complex, is highly specific for tb, making antibody to mpt64 a reagent specific for the diagnosis of tb.201222520654
antibody recognition of cancer-related gangliosides and their mimics investigated using in silico site mapping.modified gangliosides may be overexpressed in certain types of cancer, thus, they are considered a valuable target in cancer immunotherapy. structural knowledge of their interaction with antibodies is currently limited, due to the large size and high flexibility of these ligands. in this study, we apply our previously developed site mapping technique to investigate the recognition of cancer-related gangliosides by anti-ganglioside antibodies. the results reveal a potential ganglioside-binding mo ...201222536387
worm burden-dependent disruption of the porcine colon microbiota by trichuris suis infection.helminth infection in pigs serves as an excellent model for the study of the interaction between human malnutrition and parasitic infection and could have important implications in human health. we had observed that pigs infected with trichuris suis for 21 days showed significant changes in the proximal colon microbiota. in this study, interactions between worm burden and severity of disruptions to the microbial composition and metabolic potentials in the porcine proximal colon microbiota were i ...201222532855
human milk oligosaccharides: every baby needs a sugar mama.human milk oligosaccharides (hmos) are a family of structurally diverse unconjugated glycans that are highly abundant in and unique to human milk. originally, hmos were discovered as a prebiotic "bifidus factor" that serves as a metabolic substrate for desired bacteria and shapes an intestinal microbiota composition with health benefits for the breast-fed neonate. today, hmos are known to be more than just "food for bugs". an accumulating body of evidence suggests that hmos are antiadhesive anti ...201222513036
bacterial adaptation of respiration from oxic to microoxic and anoxic conditions: redox control.under a shortage of oxygen, bacterial growth can be faced mainly by two atp-generating mechanisms: (i) by synthesis of specific high-affinity terminal oxidases that allow bacteria to use traces of oxygen or (ii) by utilizing other substrates as final electron acceptors such as nitrate, which can be reduced to dinitrogen gas through denitrification or to ammonium. this bacterial respiratory shift from oxic to microoxic and anoxic conditions requires a regulatory strategy which ensures that cells ...201222098259
characterization of α2,3- and α2,6-sialyltransferases from helicobacter acinonychis.genome sequence data were used to clone and express two sialyltransferase enzymes of the gt-42 family from helicobacter acinonychis atcc 51104, a gastric disease isolate from cheetahs. the deposited genome sequence for these genes contains a large number of tandem repeat sequences in each of them: hac1267 (rqkele)(15) and hac1268 (eekllefkni)(13). we obtained two clones with different numbers of repeat sequences for the hac1267 gene homolog and a single clone for the hac1268 gene homolog. both g ...201222504533
mucosa-associated bacteria in two middle-aged women diagnosed with collagenous colitis.to characterize the colon microbiota in two women histologically diagnosed with collagenous colitis using a culture-independent method.201222529692
sialic acid metabolism and sialyltransferases: natural functions and applications.sialic acids are a family of negatively charged monosaccharides which are commonly presented as the terminal residues in glycans of the glycoconjugates on eukaryotic cell surface or as components of capsular polysaccharides or lipooligosaccharides of some pathogenic bacteria. due to their important biological and pathological functions, the biosynthesis, activation, transfer, breaking down, and recycle of sialic acids are attracting increasing attention. the understanding of the sialic acid meta ...201222526796
the relative roles of factor h binding protein, neisserial surface protein a, and lipooligosaccharide sialylation in regulation of the alternative pathway of complement on meningococci.neisseria meningitidis inhibits the alternative pathway (ap) of complement using diverse mechanisms, including expression of capsule (select serogroups), neisserial surface protein a (nspa), factor h (fh) binding protein (fhbp), and lipooligosaccharide (los) sialylation. the contribution of the latter three molecules in ap regulation in encapsulated meningococci was studied using isogenic mutants. when los was unsialylated, deleting nspa alone from group a strain a2594 (low fhbp/high nspa) signi ...201222504643
outer membrane biogenesis in escherichia coli, neisseria meningitidis, and helicobacter pylori: paradigm deviations in h. pylori.the bacterial pathogen helicobacter pylori is capable of colonizing the gastric mucosa of the human stomach using a variety of factors associated with or secreted from its outer membrane (om). lipopolysaccharide (lps) and numerous om proteins have been shown to be involved in adhesion and immune stimulation/evasion. many of these factors are essential for colonization and/or pathogenesis in a variety of animal models. despite this wide array of potential targets present on the bacterial surface, ...201222919621
catalytic mechanism of perosamine n-acetyltransferase revealed by high-resolution x-ray crystallographic studies and kinetic analyses.n-acetylperosamine is an unusual dideoxysugar found in the o-antigens of some gram-negative bacteria, including the pathogenic escherichia coli strain o157:h7. the last step in its biosynthesis is catalyzed by perb, an n-acetyltransferase belonging to the left-handed β-helix superfamily of proteins. here we describe a combined structural and functional investigation of perb from caulobacter crescentus. for this study, three structures were determined to 1.0 å resolution or better: the enzyme in ...201222443398
impact of fluoroquinolone resistance mutations on gonococcal fitness and in vivo selection for compensatory mutations.quinolone-resistant neisseria gonorrhoeae (qrng) arise from mutations in gyra (intermediate resistance) or gyra and parc (resistance). here we tested the consequence of commonly isolated gyra(91/95) and parc86 mutations on gonococcal fitness.201222492860
infection, inflammation and host carbohydrates: a glyco-evasion hypothesis.microbial immune evasion can be achieved through the expression, or mimicry, of host-like carbohydrates on the microbial cell surface to hide from detection. however, disparate reports collectively suggest that evasion could also be accomplished through the modulation of the host glycosylation pathways, a mechanism that we call the "glyco-evasion hypothesis". here, we will summarize the evidence in support of this paradigm by reviewing three separate bodies of work present in the literature. we ...201222492234
fitness of escherichia coli strains carrying expressed and partially silent incn and incp1 plasmids.understanding the survival of resistance plasmids in the absence of selective pressure for the antibiotic resistance genes they carry is important for assessing the value of interventions to combat resistant bacteria. here, several poorly explored questions regarding the fitness impact of incp1 and incn broad host range plasmids on their bacterial hosts are examined; namely, whether related plasmids have similar fitness impacts, whether this varies according to host genetic background, and what ...201222475035
a new family of membrane electron transporters and its substrates, including a new cell envelope peroxiredoxin, reveal a broadened reductive capacity of the oxidative bacterial cell envelope.the escherichia coli membrane protein dsbd functions as an electron hub that dispatches electrons received from the cytoplasmic thioredoxin system to periplasmic oxidoreductases involved in protein disulfide isomerization, cytochrome c biogenesis, and sulfenic acid reduction. here, we describe a new class of dsbd proteins, named scsb, whose members are found in proteobacteria and chlamydia. scsb has a domain organization similar to that of dsbd, but its amino-terminal domain differs significantl ...201222493033
chlamydia psittaci in ocular adnexa malt lymphoma: a possible role in lymphomagenesis and a different geographical distribution.ocular adnexa malt-lymphomas represent approximatively 5-15% of all extranodal lymphomas. almost 75% of oamls are localized in orbital fat, while 25% of cases involves conjunctive. malt-lymphomas often recognize specific environmental factors responsible of lymphoma development and progression. in particular as helicobacter pylori in gastric malt lymphomas, other bacterial infections have been recognized related to malt lymphomas in specific site. recently chlamydia psittaci has been identified ...201222472082
the promoter of rv0560c is induced by salicylate and structurally-related compounds in mycobacterium tuberculosis.mycobacterium tuberculosis, the causative agent of tuberculosis (tb), is a major global health threat. during infection, bacteria are believed to encounter adverse conditions such as iron depletion. mycobacteria synthesize iron-sequestering mycobactins, which are essential for survival in the host, via the intermediate salicylate. salicylate is a ubiquitous compound which is known to induce a mild antibiotic resistance phenotype. in m. tuberculosis salicylate highly induces the expression of rv0 ...201222485172
commensal flora, is it an unwelcomed companion as a triggering factor of autoimmune pancreatitis?the etiopathogenesis of many autoimmune disorders has not been identified. the aim of this paper is to focus on the involvement of bacterial exposure, as an environmental factor, in the pathogenesis of autoimmune pancreatitis (aip), which is broadly categorized as autoimmune disorders involving pancreatic lesions. avirulent and/or commensal bacteria, which may have an important role(s) as initiating/progressing factors in the pathogenesis of autoimmune disorder aip, will be emphasized.201222485093
glycobiology of immune responses.unlike their protein "roommates" and their nucleic acid "cousins," carbohydrates remain an enigmatic arm of biology. the central reason for the difficulty in fully understanding how carbohydrate structure and biological function are tied is the nontemplate nature of their synthesis and the resulting heterogeneity. the goal of this collection of expert reviews is to highlight what is known about how carbohydrates and their binding partners-the microbial (non-self), tumor (altered-self), and host ...201222524422
gamma heavy-chain disease: defining the spectrum of associated lymphoproliferative disorders through analysis of 13 cases.gamma heavy-chain disease (ghcd) is defined as a lymphoplasmacytic neoplasm that produces an abnormally truncated immunoglobulin gamma heavy-chain protein that lacks associated light chains. there is scant information in the literature regarding the morphologic findings in this rare disorder, but cases have often been reported to resemble lymphoplasmacytic lymphoma (lpl). to clarify the spectrum of lymphoproliferative disorders that may be associated with ghcd, this study reports the clinical, m ...201222301495
using sequence data to identify alternative routes and risk of infection: a case-study of campylobacter in scotland.genetic typing data are a potentially powerful resource for determining how infection is acquired. in this paper mlst typing was used to distinguish the routes and risks of infection of humans with campylobacter jejuni from poultry and ruminant sources201222462563
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