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the role of microbiome in central nervous system disorders.mammals live in a co-evolutionary association with the plethora of microorganisms that reside at a variety of tissue microenvironments. the microbiome represents the collective genomes of these co-existing microorganisms, which is shaped by host factors such as genetics and nutrients but in turn is able to influence host biology in health and disease. niche-specific microbiome, prominently the gut microbiome, has the capacity to effect both local and distal sites within the host. the gut microbi ...201324370461
rapid single-colony whole-genome sequencing of bacterial pathogens.as a result of the introduction of rapid benchtop sequencers, the time required to subculture a bacterial pathogen to extract sufficient dna for library preparation can now exceed the time to sequence said dna. we have eliminated this rate-limiting step by developing a protocol to generate dna libraries for whole-genome sequencing directly from single bacterial colonies grown on primary culture plates.201324370932
rapid single-colony whole-genome sequencing of bacterial pathogens.as a result of the introduction of rapid benchtop sequencers, the time required to subculture a bacterial pathogen to extract sufficient dna for library preparation can now exceed the time to sequence said dna. we have eliminated this rate-limiting step by developing a protocol to generate dna libraries for whole-genome sequencing directly from single bacterial colonies grown on primary culture plates.201324370932
competition for zinc binding in the host-pathogen interaction.due to its favorable chemical properties, zinc is used as a structural or catalytic cofactor in a very large number of proteins. despite the apparent abundance of this metal in all cell types, the intracellular pool of loosely bound zinc ions available for biological exchanges is in the picomolar range and nearly all zinc is tightly bound to proteins. in addition, to limit bacterial growth, some zinc-sequestering proteins are produced by eukaryotic hosts in response to infections. therefore, to ...201324400228
effects of genotypic and phenotypic variation on establishment are important for conservation, invasion, and infection biology.there is abundant evidence that the probability of successful establishment in novel environments increases with number of individuals in founder groups and with number of repeated introductions. theory posits that the genotypic and phenotypic variation among individuals should also be important, but few studies have examined whether founder diversity influences establishment independent of propagule pressure, nor whether the effect is model or context dependent. i summarize the results of 18 ex ...201324367109
effects of genotypic and phenotypic variation on establishment are important for conservation, invasion, and infection biology.there is abundant evidence that the probability of successful establishment in novel environments increases with number of individuals in founder groups and with number of repeated introductions. theory posits that the genotypic and phenotypic variation among individuals should also be important, but few studies have examined whether founder diversity influences establishment independent of propagule pressure, nor whether the effect is model or context dependent. i summarize the results of 18 ex ...201324367109
invasion of epithelial cells by campylobacter jejuni is independent of caveolae.caveolae are 25-100 nm flask-like membrane structures enriched in cholesterol and glycosphingolipids. researchers have proposed that campylobacter jejuni require caveolae for cell invasion based on the finding that treatment of cells with the cholesterol-depleting compounds filipin iii or methyl-β-cyclodextrin (mβcd) block bacterial internalization in a dose-dependent manner. the purpose of this study was to determine the role of caveolae and caveolin-1, a principal component of caveolae, in c. ...201324364863
a unique in vivo experimental approach reveals metabolic adaptation of the probiotic propionibacterium freudenreichii to the colon environment.propionibacterium freudenreichii is a food grade bacterium consumed both in cheeses and in probiotic preparations. its promising probiotic potential, relying largely on the active release of beneficial metabolites within the gut as well as the expression of key surface proteins involved in immunomodulation, deserves to be explored more deeply. adaptation to the colon environment is requisite for the active release of propionibacterial beneficial metabolites and constitutes a bottleneck for metab ...201324365073
the detection of foodborne bacteria on beef: the application of the electronic nose.this study aims to investigate the application of a fast electronic nose system (cyranose 320) for detecting foodborne bacteria. the system proved to be very efficient in detecting microbes in beef and sausage samples. in the first part of the study, the total viable counts (tvc) from fresh and frozen beef samples were determined using the standard microbiological method and by the application of the electronic nose. the second part applied the electronic nose to beef before and after contaminat ...201324386629
role of enteric neurotransmission in host defense and protection of the gastrointestinal tract.host defense is a vital role played by the gastrointestinal tract. as host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. the control of such barrier functions requires the integration of neural, humoral, paracrine and immune signaling, involving redundant and overlapping mechanisms to ensure, under most circumstances, the integrity of th ...201324412639
role of enteric neurotransmission in host defense and protection of the gastrointestinal tract.host defense is a vital role played by the gastrointestinal tract. as host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. the control of such barrier functions requires the integration of neural, humoral, paracrine and immune signaling, involving redundant and overlapping mechanisms to ensure, under most circumstances, the integrity of th ...201324412639
extra-intestinal and long term consequences of giardia duodenalis infections.giardiasis is the most common waterborne parasitic infection of the human intestine worldwide. the etiological agent, giardia duodenalis (syn. g. intestinalis, g. lamblia), is a flagellated, binucleated protozoan parasite which infects a wide array of mammalian hosts. human giardiasis is a true cosmopolitan pathogen, with highest prevalence in developing countries. giardiasis can present with a broad range of clinical manifestations from asymptomatic, to acute or chronic diarrheal disease associ ...201324379622
dietary nisin modulates the gastrointestinal microbial ecology and enhances growth performance of the broiler chickens.due to antimicrobial properties, nisin is one of the most commonly used and investigated bacteriocins for food preservation. surprisingly, nisin has had limited use in animal feed as well as there are only few reports on its influence on microbial ecology of the gastrointestinal tract (git). the present study therefore aimed at investigating effects of dietary nisin on broiler chicken git microbial ecology and performance in comparison to salinomycin, the widely used ionophore coccidiostat. in t ...201324376878
immune system regulation in the induction of broadly neutralizing hiv-1 antibodies.in this brief review, we discuss immune tolerance as a factor that determines the magnitude and quality of serum antibody responses to hiv-1 infection and vaccination in the context of recent work. we propose that many conserved, neutralizing epitopes of hiv-1 are weakly immunogenic because they mimic host antigens. in consequence, b cells that strongly bind these determinants are removed by the physiological process of immune tolerance. this structural mimicry may represent a significant impedi ...201324932410
immune system regulation in the induction of broadly neutralizing hiv-1 antibodies.in this brief review, we discuss immune tolerance as a factor that determines the magnitude and quality of serum antibody responses to hiv-1 infection and vaccination in the context of recent work. we propose that many conserved, neutralizing epitopes of hiv-1 are weakly immunogenic because they mimic host antigens. in consequence, b cells that strongly bind these determinants are removed by the physiological process of immune tolerance. this structural mimicry may represent a significant impedi ...201324932410
hemerythrins in the microaerophilic bacterium campylobacter jejuni help protect key iron-sulphur cluster enzymes from oxidative damage.microaerophilic bacteria are adapted to low oxygen environments, but the mechanisms by which their growth in air is inhibited are not well understood. the citric acid cycle in the microaerophilic pathogen campylobacter jejuni is potentially vulnerable, as it employs pyruvate and 2-oxoglutarate:acceptor oxidoreductases (por and oor), which contain labile (4fe-4s) centres. here, we show that both enzymes are rapidly inactivated after exposure of cells to a fully aerobic environment. we investigate ...201324245612
hemerythrins in the microaerophilic bacterium campylobacter jejuni help protect key iron-sulphur cluster enzymes from oxidative damage.microaerophilic bacteria are adapted to low oxygen environments, but the mechanisms by which their growth in air is inhibited are not well understood. the citric acid cycle in the microaerophilic pathogen campylobacter jejuni is potentially vulnerable, as it employs pyruvate and 2-oxoglutarate:acceptor oxidoreductases (por and oor), which contain labile (4fe-4s) centres. here, we show that both enzymes are rapidly inactivated after exposure of cells to a fully aerobic environment. we investigate ...201324245612
why related bacterial species bloom simultaneously in the gut: principles underlying the 'like will to like' concept.the large intestine is host to a complex ecological community composed predominantly of obligate anaerobic bacteria belonging to the classes bacteroidia and clostridia. this community confers benefits through its metabolic activities and host interactions. however, a microbial imbalance (dysbiosis) characterized by a decreased abundance of clostridia and a bloom of facultative anaerobic proteobacteria is commonly observed during inflammation in the large bowel. here we review recent insights int ...201324286560
why related bacterial species bloom simultaneously in the gut: principles underlying the 'like will to like' concept.the large intestine is host to a complex ecological community composed predominantly of obligate anaerobic bacteria belonging to the classes bacteroidia and clostridia. this community confers benefits through its metabolic activities and host interactions. however, a microbial imbalance (dysbiosis) characterized by a decreased abundance of clostridia and a bloom of facultative anaerobic proteobacteria is commonly observed during inflammation in the large bowel. here we review recent insights int ...201324286560
the potential link between gut microbiota and ige-mediated food allergy in early life.there has been a dramatic rise in the prevalence of ige-mediated food allergy over recent decades, particularly among infants and young children. the cause of this increase is unknown but one putative factor is a change in the composition, richness and balance of the microbiota that colonize the human gut during early infancy. the coevolution of the human gastrointestinal tract and commensal microbiota has resulted in a symbiotic relationship in which gut microbiota play a vital role in early li ...201324351744
antibodies to heteromeric glycolipid complexes in guillain-barré syndrome.autoantibodies are infrequently detected in the sera of patients with the demyelinating form of guillain-barré syndrome most commonly encountered in the western world, despite abundant circumstantial evidence suggesting their existence. we hypothesised that antibody specificities reliant on the cis interactions of neighbouring membrane glycolipids could explain this discrepancy, and would not have been detected by traditional serological assays using highly purified preparations of single gangli ...201324358172
sialic acid-binding ig-like lectin-7 interacts with hiv-1 gp120 and facilitates infection of cd4pos t cells and macrophages.sialic acid-binding ig-like lectin-7 (siglec-7) expression is strongly reduced on natural killer (nk) cells from hiv-1 infected viremic patients. to investigate the mechanism(s) underlying this phenomenon, we hypothesized that siglec-7 could contribute to the infection of cd4pos target cells following its interaction with hiv-1 envelope (env) glycoprotein 120 (gp120).201324330394
virulence characteristics of five new campylobacter jejuni chicken isolates.campylobacter enteritis has emerged as one of the most common forms of human diarrheal illness. in this study we have investigated the virulence potential of five new c. jejuni chicken isolates (ro14, ro19, ro24, ro29 and ro37) originated from private households in the rural regions of banat and transylvania in romania. following isolation and in vitro virulence assay, on hct-8 cells, our results show that all the c. jejuni chicken isolates overcome the virulence abilities of the highly virulent ...201324330718
rapid and reversible responses to ivig in autoimmune neuromuscular diseases suggest mechanisms of action involving competition with functionally important autoantibodies.intravenous immunoglobulin (ivig) is widely used in autoimmune neuromuscular diseases whose pathogenesis is undefined. many different effects of ivig have been demonstrated in vitro, but few studies actually identify the mechanism(s) most important in vivo. doses and treatment intervals are generally chosen empirically. recent studies in guillain-barré syndrome and chronic inflammatory demyelinating polyneuropathy show that some effects of ivig are readily reversible and highly dependent on the ...201324200120
nationwide surveillance for pathogenic microorganisms in groundwater near carcass burials constructed in south korea in 2010.widespread outbreaks of foot-and-mouth disease and avian influenza occurred in south korea during 2010. in response to the culling of many animals to attenuate the spread of disease, south korea used mass burial sites to dispose of the large number of carcasses; consequently, concerns about groundwater contamination by leachate from these burial sites are increasing. groundwater is one of the main sources of drinking water, and its cleanliness is directly related to public health. thus, this stu ...201324351737
crispr-cas immunity against phages: its effects on the evolution and survival of bacterial pathogens. 201324348245
complete genome sequence of the campylobacter coli clinical isolate 15-537360.campylobacter coli strain 15-537360 was originally isolated in 2001 from a 42-year-old patient with gastroenteritis. here, we report its complete genome sequence, which comprises a 1.7-mbp chromosome and a 29-kbp conjugative cryptic plasmid. this is the first complete genome sequence of a clinical isolate of c. coli.201324336384
the contribution of nutrient metal acquisition and metabolism to acinetobacter baumannii survival within the host.acinetobacter baumannii is a significant contributor to intensive care unit (icu) mortality causing numerous types of infection in this susceptible icu population, most notably ventilator-associated pneumonia. the substantial disease burden attributed to a. baumannii and the rapid acquisition of antibiotic resistance make this bacterium a serious health care threat. a. baumannii is equipped to tolerate the hostile host environment through modification of its metabolism and nutritional needs. amo ...201324377089
a view to a kill: the bacterial type vi secretion system.the bacterial type vi secretion system (t6ss) is an organelle that is structurally and mechanistically analogous to an intracellular membrane-attached contractile phage tail. recent studies determined that a rapid conformational change in the structure of a sheath protein complex propels t6ss spike and tube components along with antibacterial and antieukaryotic effectors out of predatory t6ss(+) cells and into prey cells. the contracted organelle is then recycled in an atp-dependent process. t6s ...201324332978
a view to a kill: the bacterial type vi secretion system.the bacterial type vi secretion system (t6ss) is an organelle that is structurally and mechanistically analogous to an intracellular membrane-attached contractile phage tail. recent studies determined that a rapid conformational change in the structure of a sheath protein complex propels t6ss spike and tube components along with antibacterial and antieukaryotic effectors out of predatory t6ss(+) cells and into prey cells. the contracted organelle is then recycled in an atp-dependent process. t6s ...201324332978
development of duplex pcr assay for detection and differentiation of typical and atypical melissococcus plutonius strains.melissococcus plutonius is the causative agent of an important honeybee disease, european foulbrood (efb). in addition to m. plutonius strains with typical characteristics (typical m. plutonius), we recently reported the presence of atypical m. plutonius, which are phenotypically and genetically distinguished from typical m. plutonius. because typical and atypical m. plutonius may have different pathogenic mechanisms, differentiation of these two types is very important for diagnosis and more ef ...201324334815
development of duplex pcr assay for detection and differentiation of typical and atypical melissococcus plutonius strains.melissococcus plutonius is the causative agent of an important honeybee disease, european foulbrood (efb). in addition to m. plutonius strains with typical characteristics (typical m. plutonius), we recently reported the presence of atypical m. plutonius, which are phenotypically and genetically distinguished from typical m. plutonius. because typical and atypical m. plutonius may have different pathogenic mechanisms, differentiation of these two types is very important for diagnosis and more ef ...201324334815
fitness benefits in fluoroquinolone-resistant salmonella typhi in the absence of antimicrobial pressure.fluoroquinolones (fq) are the recommended antimicrobial treatment for typhoid, a severe systemic infection caused by the bacterium salmonella enterica serovar typhi. fq-resistance mutations in s. typhi have become common, hindering treatment and control efforts. using in vitro competition experiments, we assayed the fitness of eleven isogenic s. typhi strains with resistance mutations in the fq target genes, gyra and parc. in the absence of antimicrobial pressure, 6 out of 11 mutants carried a s ...201324327559
antibiotic development challenges: the various mechanisms of action of antimicrobial peptides and of bacterial resistance.antimicrobial peptides (amps) are natural antibiotics produced by various organisms such as mammals, arthropods, plants, and bacteria. in addition to antimicrobial activity, amps can induce chemokine production, accelerate angiogenesis, and wound healing and modulate apoptosis in multicellular organisms. originally, their antimicrobial mechanism of action was thought to consist solely of an increase in pathogen cell membrane permeability, but it has already been shown that several amps do not mo ...201324367355
common themes and unique proteins for the uptake and trafficking of nickel, a metal essential for the virulence of helicobacter pylori.nickel is a virulence determinant for the human gastric pathogen helicobacter pylori. indeed, h. pylori possesses two nickel-enzymes that are essential for in vivo colonization, [nife] hydrogenase and urease, an abundant virulence factor that contains 24 nickel ions per active complex. because of these two enzymes, survival of h. pylori relies on an important supply of nickel, implying a tight control of its distribution and storage. in this review, we will present the pathways of activation of ...201324367767
modulation of bacterial multidrug resistance efflux pumps of the major facilitator superfamily.bacterial infections pose a serious public health concern, especially when an infectious disease has a multidrug resistant causative agent. such multidrug resistant bacteria can compromise the clinical utility of major chemotherapeutic antimicrobial agents. drug and multidrug resistant bacteria harbor several distinct molecular mechanisms for resistance. bacterial antimicrobial agent efflux pumps represent a major mechanism of clinical resistance. the major facilitator superfamily (mfs) is one o ...201325750934
identification of genes involved in low aminoglycoside-induced sos response in vibrio cholerae: a role for transcription stalling and mfd helicase.sub-inhibitory concentrations (sub-mic) of antibiotics play a very important role in selection and development of resistances. unlike escherichia coli, vibrio cholerae induces its sos response in presence of sub-mic aminoglycosides. a role for oxidized guanine residues was observed, but the mechanisms of this induction remained unclear. to select for v. cholerae mutants that do not induce low aminoglycoside-mediated sos induction, we developed a genetic screen that renders induction of sos letha ...201324319148
identification of genes involved in low aminoglycoside-induced sos response in vibrio cholerae: a role for transcription stalling and mfd helicase.sub-inhibitory concentrations (sub-mic) of antibiotics play a very important role in selection and development of resistances. unlike escherichia coli, vibrio cholerae induces its sos response in presence of sub-mic aminoglycosides. a role for oxidized guanine residues was observed, but the mechanisms of this induction remained unclear. to select for v. cholerae mutants that do not induce low aminoglycoside-mediated sos induction, we developed a genetic screen that renders induction of sos letha ...201324319148
a case-control study of incident rheumatological conditions following acute gastroenteritis during military deployment.the aim of this study was to assess the risk of incident rheumatological diagnoses (rd) associated with self-reported diarrhoea and vomiting during a first-time deployment to iraq or afghanistan. such an association would provide evidence that rd in this population may include individuals with reactive arthritis (rea) from deployment-related infectious gastroenteritis.201324319273
enhanced bactericidal effect of enterocin a in combination with thyme essential oils against l. monocytogenes and e. coli o157:h7.the combined effects of enterocin a with thymus vulgaris essential oils (eos) against listeria monocytogenes and escherichia coli o157:h7 were investigated in vitro by enumeration of surviving populations of testing pathogens and minimal inhibitory concentration (mic) determination. enterocin a was purified to homogeneity by rp-hplc from the culture fluid of enterococcus strain and thyme eos were extracted from local thymus vulgaris plants. the major constituent of thyme eos oils determined by g ...201325829595
enhanced bactericidal effect of enterocin a in combination with thyme essential oils against l. monocytogenes and e. coli o157:h7.the combined effects of enterocin a with thymus vulgaris essential oils (eos) against listeria monocytogenes and escherichia coli o157:h7 were investigated in vitro by enumeration of surviving populations of testing pathogens and minimal inhibitory concentration (mic) determination. enterocin a was purified to homogeneity by rp-hplc from the culture fluid of enterococcus strain and thyme eos were extracted from local thymus vulgaris plants. the major constituent of thyme eos oils determined by g ...201325829595
inflammatory diarrhea due to enteroaggregative escherichia coli: evidence from clinical and mice model studies.this study was conducted to determine the role of enteroaggregative escherichia coli (eaec) in inflammatory diarrhea among hospitalized patients in kolkata. the inflammatory pathogenesis of eaec was established in mice model and histopathological studies. presence of fecal leucocytes (flcs) can be suspected for eaec infection solely or as a mixed with other enteric pathogens.201324294997
lipid bilayer nanodisc platform for investigating polyprenol-dependent enzyme interactions and activities.membrane-bound polyprenol-dependent pathways are important for the assembly of essential glycoconjugates in all domains of life. however, despite their prevalence, the functional significance of the extended linear polyprenyl groups in the interactions of the glycan substrates, the biosynthetic enzymes that act upon them, and the membrane bilayer in which they are embedded remains a mystery. these interactions are investigated simultaneously and uniquely through application of the nanodisc membr ...201324302767
kpsc and kpss are retaining 3-deoxy-d-manno-oct-2-ulosonic acid (kdo) transferases involved in synthesis of bacterial capsules.capsular polysaccharides (cpss) are high-molecular-mass cell-surface polysaccharides, that act as important virulence factors for many pathogenic bacteria. several clinically important gram-negative pathogens share similar systems for cps biosynthesis and export; examples include escherichia coli, campylobacter jejuni, haemophilus influenzae, neisseria meningitidis, and pasteurella multocida. each cps contains a serotype-specific repeat-unit structure, but the glycans all possess a lipid moiety ...201324302764
the complex methylome of the human gastric pathogen helicobacter pylori.the genome of helicobacter pylori is remarkable for its large number of restriction-modification (r-m) systems, and strain-specific diversity in r-m systems has been suggested to limit natural transformation, the major driving force of genetic diversification in h. pylori. we have determined the comprehensive methylomes of two h. pylori strains at single base resolution, using single molecule real-time (smrt®) sequencing. for strains 26695 and j99-r3, 17 and 22 methylated sequence motifs were id ...201324302578
the complex methylome of the human gastric pathogen helicobacter pylori.the genome of helicobacter pylori is remarkable for its large number of restriction-modification (r-m) systems, and strain-specific diversity in r-m systems has been suggested to limit natural transformation, the major driving force of genetic diversification in h. pylori. we have determined the comprehensive methylomes of two h. pylori strains at single base resolution, using single molecule real-time (smrt®) sequencing. for strains 26695 and j99-r3, 17 and 22 methylated sequence motifs were id ...201324302578
environmental influences on the onset and clinical course of crohn's disease-part 2: infections and medication use.the pathogenesis of crohn's disease (cd) involves host, genetic, and environmental factors. these factors result in disturbances in the innate and adaptive immune systems and composition of the intestinal microbiota. epidemiologic and migration studies support an environmental component in the development of cd. environmental risk factors include childhood hygiene, air pollution, breastfeeding, smoking, diet, stress, exercise, seasonal variation, appendectomy, medications, and infections. this 2 ...201324772046
haemophilus parainfluenzae expresses diverse lipopolysaccharide o-antigens using abc transporter and wzy polymerase-dependent mechanisms.lipopolysaccharide o-antigens are the basis of serotyping schemes for gram negative bacteria and help to determine the nature of host-bacterial interactions. haemophilus parainfluenzae is a normal commensal of humans but is also an occasional pathogen. the prevalence, diversity and biosynthesis of o-antigens were investigated in this species for the first time. 18/18 commensal h. parainfluenzae isolates contain a o-antigen biosynthesis gene cluster flanked by glna and pepb, the same position as ...201324035104
salmonella pathogenicity and host adaptation in chicken-associated serovars.enteric pathogens such as salmonella enterica cause significant morbidity and mortality. s. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. s. enterica serovars such as s. typhi, s. dublin, and s. gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while s. enteritidis and s. typhimurium have broad host ranges. this review examines how s. enterica ...201324296573
description of a riboflavin biosynthetic gene variant prevalent in the phylum proteobacteria.riboflavin (vitamin b2) is the precursor of flavin mononucleotide and flavin adenine dinucleotide, which are cofactors essential for a host of intracellular redox reactions. microorganisms synthesize flavins de novo to fulfill nutritional requirements, but it is becoming increasingly clear that flavins play a wider role in cellular physiology than was previously appreciated. flavins mediate diverse processes beyond the cytoplasmic membrane, including iron acquisition, extracellular respiration, ...201324097946
identification and characterization of novel helicobacter pylori apo-fur-regulated target genes.in helicobacter pylori, the ferric uptake regulator (fur) has evolved additional regulatory functions not seen in other bacteria; it can repress and activate different groups of genes in both its iron-bound and apo forms. because little is understood about the process of apo-fur repression and because only two apo-fur-repressed genes (pfr and sodb) have previously been identified, we sought to expand our understanding of this type of regulation. utilizing published genomic studies, we selected t ...201324097951
biochemical activities of streptococcus pneumoniae serotype 2 capsular glycosyltransferases and significance of suppressor mutations affecting the initiating glycosyltransferase cps2e.the capsular polysaccharide (cps) is essential for streptococcus pneumoniae virulence. its synthesis requires multiple enzymes, and defects that block completion of the pathway can be lethal in the absence of secondary suppressor mutations. in this study, we examined the functions of three capsular glycosyltransferases (cps2f, cps2g, and cps2i) involved in serotype 2 cps synthesis, whose deletions select for secondary mutations. we demonstrate that cps2f is a rhamnosyltransferase that catalyzes ...201324097952
quantitative detection of vibrio cholera toxin by real-time and dynamic cytotoxicity monitoring.we report here the quantitative detection of vibrio cholerae toxin (ct) in isolates and stool specimens by dynamic monitoring of the full course of ct-mediated cytotoxicity in a real-time cell analysis (rtca) system. four cell lines, including y-1 mouse adrenal tumor cells, chinese hamster ovary (cho) cells, small intestine epithelial (fhs74int) cells, and mouse adrenal gland (pc12-adh) cells, were evaluated for their suitability for ct-induced cytotoxicity testing. among them, the y-1 line was ...201324048535
risk factors for campylobacteriosis in two washington state counties with high numbers of dairy farms.campylobacteriosis is a frequently reported, food-borne, human bacterial disease that can be associated with ruminant reservoirs, although public health messages primarily focus on poultry. in washington state, the two counties with the highest concentrations of dairy cattle also report the highest incidences of campylobacteriosis. conditional logistic regression analysis of case-control data from both counties found living or working on a dairy farm (odds ratio [or], 6.7 [95% confidence interva ...201324025908
clinical evaluation of a real-time pcr assay for identification of salmonella, shigella, campylobacter (campylobacter jejuni and c. coli), and shiga toxin-producing escherichia coli isolates in stool specimens.enteric illness affects millions of individuals annually in the united states and results in >50,000 hospitalizations. the rapid and accurate identification of bacterial pathogens associated with gastroenteritis can aid acute patient management decisions, including the use of antibiotic therapy and infection control. this study compared the progastro sscs multiplex real-time pcr assay (gen-probe prodesse, san diego, ca) to culture for the identification of campylobacter spp. (campylobacter jejun ...201324048539
a distant homologue of the flgt protein interacts with motb and flil and is essential for flagellar rotation in rhodobacter sphaeroides.in this work, we describe a periplasmic protein that is essential for flagellar rotation in rhodobacter sphaeroides. this protein is encoded upstream of flga, and its expression is dependent on the flagellar master regulator fleq and on the class iii flagellar activator flet. sequence comparisons suggest that this protein is a distant homologue of flgt. we show evidence that in r. sphaeroides, flgt interacts with the periplasmic regions of motb and flil and with the flagellar protein motf, which ...201324056105
effect of incubation temperature on the detection of thermophilic campylobacter species from freshwater beaches, nearby wastewater effluents, and bird fecal droppings.this large-scale study compared incubation temperatures (37°c versus 42°c) to study the detection of thermophilic campylobacter species, including campylobacter jejuni, c. coli, and c. lari, in various surface water samples and bird fecal droppings around hamilton harbor, lake ontario. the putative culture isolates obtained from incubation temperatures of 37 and 42°c were confirmed by campylobacter genus- and species-specific triplex pcr assays targeting the 16s rrna gene and the 16s-23s rrna ge ...201324077717
accumulation and inactivation of avian influenza virus by the filter-feeding invertebrate daphnia magna.the principal mode of avian influenza a virus (aiv) transmission among wild birds is thought to occur via an indirect fecal-oral route, whereby individuals are exposed to virus from the environment through contact with virus-contaminated water. aiv can remain viable for an extended time in water; however, little is known regarding the influence of the biotic community (i.e., aquatic invertebrates) on virus persistence and infectivity in aquatic environments. we conducted laboratory experiments t ...201324038705
effect of bacteriophage application on campylobacter jejuni loads in commercial broiler flocks.campylobacteriosis is the most frequent food-borne human enteritis. the major source for infection with campylobacter spp. is broiler meat. risk assessments consider the reduction of campylobacter in primary production to be most beneficial for human health. the aim of this study was to test the efficacy of a bacteriophage application under commercial conditions which had proved to be effective in previous noncommercial studies under controlled experimental conditions. a phage cocktail for campy ...201324077703
impact of rurality, broiler operations, and community socioeconomic factors on the risk of campylobacteriosis in maryland.we evaluated the combined impact of community-level environmental and socioeconomic factors on the risk of campylobacteriosis.201324134343
exploring the risks of phage application in the environment.interest in using bacteriophages to control the growth and spread of bacterial pathogens is being revived in the wake of widespread antibiotic resistance. however, little is known about the ecological effects that high concentrations of phages in the environment might have on natural microbial communities. we review the current evidence suggesting phage-mediated environmental perturbation, with a focus on agricultural examples, and describe the potential implications for human health and agricul ...201324348468
aptamer-based analysis: a promising alternative for food safety control.ensuring food safety is nowadays a top priority of authorities and professional players in the food supply chain. one of the key challenges to determine the safety of food and guarantee a high level of consumer protection is the availability of fast, sensitive and reliable analytical methods to identify specific hazards associated to food before they become a health problem. the limitations of existing methods have encouraged the development of new technologies, among them biosensors. success in ...201324287543
foodborne campylobacter: infections, metabolism, pathogenesis and reservoirs.campylobacter species are a leading cause of bacterial-derived foodborne illnesses worldwide. the emergence of this bacterial group as a significant causative agent of human disease and their propensity to carry antibiotic resistance elements that allows them to resist antibacterial therapy make them a serious public health threat. campylobacter jejuni and campylobacter coli are considered to be the most important enteropathogens of this genus and their ability to colonize and survive in a wide ...201324287853
a case of acute motor and sensory axonal neuropathy following hepatitis a infection.acute motor and sensory axonal neuropathy (amsan) are recently described subtypes of guillain-barre syndrome characterized by acute onset of distal weakness, loss of deep tendon reflexes, and sensory symptoms. a 21-yr-old male was transferred to our hospital due to respiration difficulties and progressive weakness. in laboratory findings, immunoglobulin m antibodies against hepatitis a were detected in blood and cerebrospinal fluid. the findings of motor nerve conduction studies showed markedly ...201324339719
the campylobacter jejuni cj0268c protein is required for adhesion and invasion in vitro.adherence of campylobacter jejuni to its particular host cells is mediated by several pathogen proteins. we screened a transposon-based mutant library of c. jejuni in order to identify clones with an invasion deficient phenotype towards caco2 cells and detected a mutant with the transposon insertion in gene cj0268c. in vitro characterization of a generated non-random mutant, the mutant complemented with an intact copy of cj0268c and parental strain nctc 11168 confirmed the relevance of cj0268c i ...201324303031
challenges in diagnostic accuracy studies in primary care: the fecal calprotectin example.low disease prevalence and lack of uniform reference standards in primary care induce methodological challenges for investigating the diagnostic accuracy of a test. we present a study design that copes with these methodological challenges and discuss the methodological implications of our choices, using a quality assessment tool for diagnostic accuracy studies (quadas-2).201324274463
global transcriptional response to heat shock of the legume symbiont mesorhizobium loti maff303099 comprises extensive gene downregulation.rhizobia, the bacterial legume symbionts able to fix atmospheric nitrogen inside root nodules, have to survive in varied environmental conditions. the aim of this study was to analyse the transcriptional response to heat shock of mesorhizobium loti maff303099, a rhizobium with a large multipartite genome of 7.6 mb that nodulates the model legume lotus japonicus. using microarray analysis, extensive transcriptomic changes were detected in response to heat shock: 30% of the protein-coding genes we ...201324277738
global transcriptional response to heat shock of the legume symbiont mesorhizobium loti maff303099 comprises extensive gene downregulation.rhizobia, the bacterial legume symbionts able to fix atmospheric nitrogen inside root nodules, have to survive in varied environmental conditions. the aim of this study was to analyse the transcriptional response to heat shock of mesorhizobium loti maff303099, a rhizobium with a large multipartite genome of 7.6 mb that nodulates the model legume lotus japonicus. using microarray analysis, extensive transcriptomic changes were detected in response to heat shock: 30% of the protein-coding genes we ...201324277738
molecular analysis of an alternative n-glycosylation machinery by functional transfer from actinobacillus pleuropneumoniae to escherichia coli.n-linked protein glycosylation is a frequent post-translational modification that can be found in all three domains of life. in a canonical, highly conserved pathway, an oligosaccharide is transferred by a membrane-bound oligosaccharyltransferase from a lipid donor to asparagines in the sequon nx(s/t) of secreted polypeptides. the δ-proteobacterium actinobacillus pleuropneumoniae encodes an unusual pathway for n-linked protein glycosylation. this pathway takes place in the cytoplasm and is media ...201324275653
molecular analysis of an alternative n-glycosylation machinery by functional transfer from actinobacillus pleuropneumoniae to escherichia coli.n-linked protein glycosylation is a frequent post-translational modification that can be found in all three domains of life. in a canonical, highly conserved pathway, an oligosaccharide is transferred by a membrane-bound oligosaccharyltransferase from a lipid donor to asparagines in the sequon nx(s/t) of secreted polypeptides. the δ-proteobacterium actinobacillus pleuropneumoniae encodes an unusual pathway for n-linked protein glycosylation. this pathway takes place in the cytoplasm and is media ...201324275653
microfluidic biosensor array with integrated poly(2,7-carbazole)/fullerene-based photodiodes for rapid multiplexed detection of pathogens.a multiplexed microfluidic biosensor made of poly(methylmethacrylate) (pmma) was integrated into an array of organic blend heterojunction photodiodes (opds) for chemiluminescent detection of pathogens. waterborne escherichia coli o157:h7, campylobacter jejuni and adenovirus were targeted in the pmma chip, and detection of captured pathogens was conducted by poly(2,7-carbazole)/fullerene opds which showed a responsivity over 0.20 a/w at 425 nm. the limits of chemiluminescent detection were 5 × 10 ...201324287522
characterization of the biochemical properties of campylobacter jejuni rnase iii.campylobacter jejuni is a foodborne bacterial pathogen, which is now considered as a leading cause of human bacterial gastroenteritis. the information regarding ribonucleases in c. jejuni is very scarce but there are hints that they can be instrumental in virulence mechanisms. namely, pnpase (polynucleotide phosphorylase) was shown to allow survival of c. jejuni in refrigerated conditions, to facilitate bacterial swimming, cell adhesion, colonization and invasion. in several microorganisms pnpas ...201324073828
network portal: a database for storage, analysis and visualization of biological networks.the ease of generating high-throughput data has enabled investigations into organismal complexity at the systems level through the inference of networks of interactions among the various cellular components (genes, rnas, proteins and metabolites). the wider scientific community, however, currently has limited access to tools for network inference, visualization and analysis because these tasks often require advanced computational knowledge and expensive computing resources. we have designed the ...201324271392
network portal: a database for storage, analysis and visualization of biological networks.the ease of generating high-throughput data has enabled investigations into organismal complexity at the systems level through the inference of networks of interactions among the various cellular components (genes, rnas, proteins and metabolites). the wider scientific community, however, currently has limited access to tools for network inference, visualization and analysis because these tasks often require advanced computational knowledge and expensive computing resources. we have designed the ...201324271392
detection of enteric pathogens by the nodosome.nucleotide-binding oligomerization domain protein (nod)1 and nod2 participate in signaling pathways that detect pathogen-induced processes, such as the presence of peptidoglycan fragments in the host cell cytosol, as danger signals. recent work suggests that peptidoglycan fragments activate nod1 indirectly, through activation of the small rho gtpase ras-related c3 botulinum toxin substrate 1 (rac1). excessive activation of small rho gtpases by virulence factors of enteric pathogens also triggers ...201324268520
detection of enteric pathogens by the nodosome.nucleotide-binding oligomerization domain protein (nod)1 and nod2 participate in signaling pathways that detect pathogen-induced processes, such as the presence of peptidoglycan fragments in the host cell cytosol, as danger signals. recent work suggests that peptidoglycan fragments activate nod1 indirectly, through activation of the small rho gtpase ras-related c3 botulinum toxin substrate 1 (rac1). excessive activation of small rho gtpases by virulence factors of enteric pathogens also triggers ...201324268520
a rare case intractable diarrhea secondary to clostridium difficile and cytomegalovirus coinfection.male, 63 final diagnosis: cytomegalo virus (cmv) infection symptoms: diarrhea medication:- clinical procedure:- specialty: infectious diseases.201324298304
rapid diagnosis of diarrhea caused by shigella sonnei using dipsticks; comparison of rectal swabs, direct stool and stool culture.we evaluated a dipstick test for rapid detection of shigella sonnei on bacterial colonies, directly on stools and from rectal swabs because in actual field situations, most pathologic specimens for diagnosis correspond to stool samples or rectal swabs.201324278267
glycotherapy: new advances inspire a reemergence of glycans in medicine.the beginning of the 20(th) century marked the dawn of modern medicine with glycan-based therapies at the forefront. however, glycans quickly became overshadowed as dna- and protein-focused treatments became readily accessible. the recent development of new tools and techniques to study and produce structurally defined carbohydrates has spurred renewed interest in the therapeutic applications of glycans. this review focuses on advances within the past decade that are bringing glycan-based treatm ...201324269151
glycotherapy: new advances inspire a reemergence of glycans in medicine.the beginning of the 20(th) century marked the dawn of modern medicine with glycan-based therapies at the forefront. however, glycans quickly became overshadowed as dna- and protein-focused treatments became readily accessible. the recent development of new tools and techniques to study and produce structurally defined carbohydrates has spurred renewed interest in the therapeutic applications of glycans. this review focuses on advances within the past decade that are bringing glycan-based treatm ...201324269151
the route less taken: pulmonary models of enteric gram-negative infection.many pathogens are capable of causing a fulminant infection in pulmonary tissues of mammals. animal models have provided an extensive understanding of the genetic and molecular mechanisms of bacterial pathogenesis as well as host immune response in the lungs. many clinically relevant gram-negative bacteria are host-restricted. thus, the powerful, informative tools of mouse models are not available for study with these organisms. however, over the past 30 years, enterprising work has demonstrated ...201324259516
the route less taken: pulmonary models of enteric gram-negative infection.many pathogens are capable of causing a fulminant infection in pulmonary tissues of mammals. animal models have provided an extensive understanding of the genetic and molecular mechanisms of bacterial pathogenesis as well as host immune response in the lungs. many clinically relevant gram-negative bacteria are host-restricted. thus, the powerful, informative tools of mouse models are not available for study with these organisms. however, over the past 30 years, enterprising work has demonstrated ...201324259516
phylogeny of cas9 determines functional exchangeability of dual-rna and cas9 among orthologous type ii crispr-cas systems.the crispr-cas-derived rna-guided cas9 endonuclease is the key element of an emerging promising technology for genome engineering in a broad range of cells and organisms. the dna-targeting mechanism of the type ii crispr-cas system involves maturation of tracrrna:crrna duplex (dual-rna), which directs cas9 to cleave invading dna in a sequence-specific manner, dependent on the presence of a protospacer adjacent motif (pam) on the target. we show that evolution of dual-rna and cas9 in bacteria pro ...201324270795
phylogeny of cas9 determines functional exchangeability of dual-rna and cas9 among orthologous type ii crispr-cas systems.the crispr-cas-derived rna-guided cas9 endonuclease is the key element of an emerging promising technology for genome engineering in a broad range of cells and organisms. the dna-targeting mechanism of the type ii crispr-cas system involves maturation of tracrrna:crrna duplex (dual-rna), which directs cas9 to cleave invading dna in a sequence-specific manner, dependent on the presence of a protospacer adjacent motif (pam) on the target. we show that evolution of dual-rna and cas9 in bacteria pro ...201324270795
clostridium difficile and inflammatory bowel disease: role in pathogenesis and implications in treatment.clostridium difficile (c. difficile) is the leading cause of antibiotic associated colitis and nosocomial diarrhea. patients with inflammatory bowel disease (ibd) are at increased risk of developing c. difficile infection (cdi), have worse outcomes of cdi-including higher rates of colectomy and death, and experience higher rates of recurrence. however, it is still not clear whether c. difficile is a cause of ibd or a consequence of the inflammatory state in the intestinal environment. the burden ...201324282348
enteric bacterial proteases in inflammatory bowel disease- pathophysiology and clinical implications.numerous reports have identified a dysbiosis in the intestinal microbiota in patients suffering from inflammatory bowel diseases (ibd), yet the mechanism(s) in which this complex microbial community initiates or perpetuates inflammation remains unclear. the purpose of this review is to present evidence for one such mechanism that implicates enteric microbial derived proteases in the pathogenesis of ibd. we highlight and discuss studies demonstrating that proteases and protease receptors are abun ...201324431894
complete genome sequence of universal bacteriophage host strain campylobacter jejuni subsp. jejuni pt14.campylobacter jejuni strain pt14 is a clinical isolate previously used to propagate bacteriophages in the united kingdom phage typing scheme. the strain has proven useful in the isolation of campylobacter bacteriophages from several sources, and it functions as a model host in phage therapy experiments with poultry and poultry meat.201324265498
implication of lateral genetic transfer in the emergence of aeromonas hydrophila isolates of epidemic outbreaks in channel catfish.to investigate the molecular basis of the emergence of aeromonas hydrophila responsible for an epidemic outbreak of motile aeromonad septicemia of catfish in the southeastern united states, we sequenced 11 a. hydrophila isolates that includes five reference and six recent epidemic isolates. comparative genomics revealed that recent epidemic a. hydrophila isolates are highly clonal, whereas reference isolates are greatly diverse. we identified 55 epidemic-associated genetic regions with 313 predi ...201324278351
glycosylation of the escherichia coli tiba self-associating autotransporter influences the conformation and the functionality of the protein.the self-associating autotransporters (saats) are multifunctional secreted proteins of escherichia coli, comprising the aida-i, tiba and ag43 proteins. one of their characteristics is that they can be glycosylated. glycosylation of aida-i and ag43 have been investigated, but not that of tiba. it is still not clear whether glycosylation of the saats affect their structure or their functionality. therefore, we have looked at the effects of glycosylation on the tiba adhesin/invasin. tiba is glycosy ...201324278316
filling out the structural map of the ntf2-like superfamily.the ntf2-like superfamily is a versatile group of protein domains sharing a common fold. the sequences of these domains are very diverse and they share no common sequence motif. these domains serve a range of different functions within the proteins in which they are found, including both catalytic and non-catalytic versions. clues to the function of protein domains belonging to such a diverse superfamily can be gleaned from analysis of the proteins and organisms in which they are found.201324246060
transabdominal ultrasonography of the small bowel.in the era of double balloon enteroscopy, capsule endoscopy, ct, and mri enterography is transabdominal ultrasonography (tus) underestimated method for evaluation of small bowel pathology. as often initial imagine method in abdominal complaints, nowadays has tus much better diagnostic potential than two decades ago. high-resolution ultrasound probes with harmonic imaging significantly improve resolution of bowel wall in real time, with possibility to asses bowel peristalsis. color flow doppler e ...201324348544
genome variations associated with viral susceptibility and calcification in emiliania huxleyi.emiliania huxleyi, a key player in the global carbon cycle is one of the best studied coccolithophores with respect to biogeochemical cycles, climatology, and host-virus interactions. strains of e. huxleyi show phenotypic plasticity regarding growth behaviour, light-response, calcification, acidification, and virus susceptibility. this phenomenon is likely a consequence of genomic differences, or transcriptomic responses, to environmental conditions or threats such as viral infections. we used a ...201324260453
the exoribonuclease polynucleotide phosphorylase influences the virulence and stress responses of yersiniae and many other pathogens.microbes are incessantly challenged by both biotic and abiotic stressors threatening their existence. therefore, bacterial pathogens must possess mechanisms to successfully subvert host immune defenses as well as overcome the stress associated with host-cell encounters. to achieve this, bacterial pathogens typically experience a genetic re-programming whereby anti-host/stress factors become expressed and eventually translated into effector proteins. in that vein, the bacterial host-cell induced ...201324312901
deg 10, an update of the database of essential genes that includes both protein-coding genes and noncoding genomic elements.the combination of high-density transposon-mediated mutagenesis and high-throughput sequencing has led to significant advancements in research on essential genes, resulting in a dramatic increase in the number of identified prokaryotic essential genes under diverse conditions and a revised essential-gene concept that includes all essential genomic elements, rather than focusing on protein-coding genes only. deg 10, a new release of the database of essential genes (available at http://www.essenti ...201324243843
deg 10, an update of the database of essential genes that includes both protein-coding genes and noncoding genomic elements.the combination of high-density transposon-mediated mutagenesis and high-throughput sequencing has led to significant advancements in research on essential genes, resulting in a dramatic increase in the number of identified prokaryotic essential genes under diverse conditions and a revised essential-gene concept that includes all essential genomic elements, rather than focusing on protein-coding genes only. deg 10, a new release of the database of essential genes (available at http://www.essenti ...201324243843
methods for recovering microorganisms from solid surfaces used in the food industry: a review of the literature.various types of surfaces are used today in the food industry, such as plastic, stainless steel, glass, and wood. these surfaces are subject to contamination by microorganisms responsible for the cross-contamination of food by contact with working surfaces. the haccp-based processes are now widely used for the control of microbial hazards to prevent food safety issues. this preventive approach has resulted in the use of microbiological analyses of surfaces as one of the tools to control the hygi ...201324240728
modification of intestinal microbiota and its consequences for innate immune response in the pathogenesis of campylobacteriosis.campylobacter jejuni is the leading cause of bacterial food-borne gastroenteritis in the world, and thus one of the most important public health concerns. the initial stage in its pathogenesis after ingestion is to overcome colonization resistance that is maintained by the human intestinal microbiota. but how it overcomes colonization resistance is unknown. recently developed humanized gnotobiotic mouse models have provided deeper insights into this initial stage and host's immune response. thes ...201324324507
ultrasensitive norovirus detection using dna aptasensor technology.dna aptamers were developed against murine norovirus (mnv) using selex (systematic evolution of ligands by exponential enrichment). nine rounds of selex led to the discovery of ag3, a promising aptamer with very high affinity for mnv as well as for lab-synthesized capsids of a common human norovirus (hunov) outbreak strain (gii.3). using fluorescence anisotropy, ag3 was found to bind with mnv with affinity in the low picomolar range. the aptamer could cross-react with hunov though it was selecte ...201324244426
source attribution of human campylobacter isolates by mlst and fla-typing and association of genotypes with quinolone resistance.campylobacteriosis is the most frequent zoonosis in developed countries and various domestic animals can function as reservoir for the main pathogens campylobacter jejuni and campylobacter coli. in the present study we compared population structures of 730 c. jejuni and c. coli from human cases, 610 chicken, 159 dog, 360 pig and 23 cattle isolates collected between 2001 and 2012 in switzerland. all isolates had been typed with multi locus sequence typing (mlst) and flab-typing and their genotypi ...201324244747
microbial endocrinology in the microbiome-gut-brain axis: how bacterial production and utilization of neurochemicals influence behavior. 201324244158
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