Publications

TitleAbstractYear
Filter
PMID(sorted descending)
Filter
unexpected diversity of signal peptides in prokaryotes.signal peptides are a cornerstone mechanism for cellular protein localization, yet until now experimental determination of signal peptides has come from only a narrow taxonomic sampling. as a result, the dominant view is that sec-cleaved signal peptides in prokaryotes are defined by a canonical axa motif. although other residues are permitted in the motif, alanine is by far the most common. here we broadly examine proteomics data to reveal the signal peptide sequences for 32 bacterial and archae ...201223169999
cross-sectional study of leptospira seroprevalence in humans, rats, mice, and dogs in a main tropical sea-port city.samples were collected from 128 symptomatic humans, 83 dogs, 49 mice, and 20 rats (rattus rattus: 16; rattus norvegicus: 4) in neighborhoods where human leptospirosis have been reported within the principal sea-port city of colombia. seroprevalences were assessed against 19 pathogenic, 1 intermediate pathogenic, and 1 saprophytic leptospira serogroups. pathogenic leptospira were confirmed using conventional leptospira-specific polymerase chain-reaction and pulsed-field gel electrophoresis analys ...201323149584
comparative analysis of leptospira strains isolated from environmental soil and water in the philippines and japan.there have been few reports on the epidemiological analysis of environmental leptospira isolates. this is probably because the isolation of leptospires from the environment was usually unsuccessful due to the overgrowth of contaminants and the slow growth of leptospira. in this study, we collected a total of 88 samples of soil and water from three sites: metro manila and nueva ecija, philippines (an area where leptospira is now endemic), and fukuoka, japan (an area where leptospira was once ende ...201323144130
assessment of real-time pcr assay for detection of rickettsia spp. and rickettsia rickettsii in banked clinical samples.two novel real-time pcr assays were developed for the detection of rickettsia spp. one assay detects all tested rickettsia spp.; the other is specific for rickettsia rickettsii. evaluation using dna from human blood and tissue samples showed both assays to be more sensitive than nested pcr assays currently in use at the cdc.201323135935
accuracy of a dual path platform (dpp) assay for the rapid point-of-care diagnosis of human leptospirosis.diagnosis of leptospirosis by the gold standard serologic assay, the microscopic agglutination test (mat), requires paired sera and is not widely available. we developed a rapid assay using immunodominant leptospira immunoglobulin-like (lig) proteins in a dual path platform (dpp). this study aimed to evaluate the assay's diagnostic performance in the setting of urban transmission.201223133686
leptospira and inflammation.leptospirosis is an important zoonosis and has a worldwide impact on public health. this paper will discuss both the role of immunogenic and pathogenic molecules during leptospirosis infection and possible new targets for immunotherapy against leptospira components. leptospira, possess a wide variety of mechanisms that allow them to evade the host immune system and cause infection. many molecules contribute to the ability of leptospira to adhere, invade, and colonize. the recent sequencing of th ...201223132959
molecular typing of leptospira interrogans strains isolated from rattus tanezumi in guizhou province, southwest of china.to identify and type three leptospires isolated from rattus tanezumi in guizhou province by using three molecular techniques (pfge, mlva, and mlst), reveal the molecular characteristic of causative agents of local leptospirosis and evaluate these three molecular methods based on their detection resolution and efficiency.201223122311
plasminogen binding proteins and plasmin generation on the surface of leptospira spp.: the contribution to the bacteria-host interactions.leptospirosis is considered a neglected infectious disease of human and veterinary concern. although extensive investigations on host-pathogen interactions have been pursued by several research groups, mechanisms of infection, invasion and persistence of pathogenic leptospira spp. remain to be elucidated. we have reported the ability of leptospires to bind human plasminogen (plg) and to generate enzimatically active plasmin (pla) on the bacteria surface. pla-coated leptospira can degrade immobil ...201223118516
bacterial plasminogen receptors: mediators of a multifaceted relationship.multiple species of bacteria are able to sequester the host zymogen plasminogen to the cell surface. once localised to the bacterial surface, plasminogen can act as a cofactor in adhesion, or, following activation to plasmin, provide a source of potent proteolytic activity. numerous bacterial plasminogen receptors have been identified, and the mechanisms by which they interact with plasminogen are diverse. here we provide an overview of bacterial plasminogen receptors and discuss the diverse rol ...201223118502
temporal trends in bulk milk antibodies to salmonella, neospora caninum, and leptospira interrogans serovar hardjo in irish dairy herds.bulk milk samples were collected from 309 irish dairy herds at four time points during 2009 and tested for antibodies to salmonella spp., n. caninum, and l. hardjo, three abortifacient agents in irish dairy herds. of the 312 study herds, 49% vaccinated against salmonella and 76% vaccinated against l. hardjo. in unvaccinated herds, the overall prevalence of antibody positive herds was 49% for salmonella, 19% for n. caninum and 86% for l. hardjo. there was no association between both testing posit ...201323117041
rapid isolation and susceptibility testing of leptospira spp. using a new solid medium, lvw agar.pathogenic leptospira spp., the causative agents of leptospirosis, are slow-growing gram-negative spirochetes. isolation of leptospira from clinical samples and testing of antimicrobial susceptibility are difficult and time-consuming. here, we describe the development of a new solid medium that facilitates more-rapid growth of leptospira spp. and the use of this medium to evaluate the etest's performance in determining antimicrobial mics to drugs in common use for leptospirosis. the medium was d ...201323114772
a survey of rodent-borne pathogens carried by wild rattus spp. in northern vietnam.to examine the prevalence of human pathogens carried by rats in urban areas in hanoi and hai phong, vietnam, we live-trapped 100 rats in january 2011 and screened them for a panel of bacteria and viruses. antibodies against leptospira interrogans (22·0%), seoul virus (14·0%) and rat hepatitis e virus (23·0%) were detected in rats, but antibodies against yersinia pestis were not detected. antibodies against l. interrogans and seoul virus were found only in adult rats. in contrast, antibodies to r ...201323114204
in vivo cell aggregations of a recent swine biofilm-forming isolate of leptospira interrogans strain from argentina.leptospirosis is a zoonosis of ubiquitous distribution caused by spirochetes. leptospires exist either as saprophytic water-associated organisms or as animal pathogens that can survive in water. previous works have demonstrated that both saprophytic and pathogenic leptospires are able to produce functional biofilms, which consist of a community of bacteria embedded in an extracellular matrix attached to a surface. this structure is believed to provide protection from environmental aggressiveness ...201223102459
characterization of lic11207, a novel leptospiral protein that is recognized by human convalescent sera and prevents apoptosis of polymorphonuclear leukocytes.we report the study of a predicted outer-membrane leptospiral protein encoded by the gene lic11207. this protein is conserved in several pathogenic leptospiral strains but is absent in the saprophyte leptospira biflexa. this putative outer-membrane protein has a domain of unknown function (duf) 1565 found in several phylogenetically diverse bacteria and in the archaeon methanosarcina acetivorans. the gene was cloned and expressed in escherichia coli bl21 (si) strain using the expression vector p ...201323092690
evolutionary analyses of non-genealogical bonds produced by introgressive descent.all evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. however, many other kinds of processes contribute to evolutionary diversity. in vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. in what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated ...201223090996
humanized tlr4/md-2 mice reveal lps recognition differentially impacts susceptibility to yersinia pestis and salmonella enterica.although lipopolysaccharide (lps) stimulation through the toll-like receptor (tlr)-4/md-2 receptor complex activates host defense against gram-negative bacterial pathogens, how species-specific differences in lps recognition impact host defense remains undefined. herein, we establish how temperature dependent shifts in the lipid a of yersinia pestis lps that differentially impact recognition by mouse versus human tlr4/md-2 dictate infection susceptibility. when grown at 37°c, y. pestis lps is hy ...201223071439
exposure to selected pathogens in to selected pathogens in geoffroy's cats and domestic carnivores from central argentina.wild carnivores share a high percentage of parasites and viruses with closely related domestic carnivores. because of increased overlap and potential contact with domestic species, we conducted a retrospective serosurvey for 11 common carnivore pathogens in 40 geoffroy's cats (leopardus geoffroyi) sampled between 2000 and 2008 within or near two protected areas in central argentina (lihué calel national park, la pampa, and campos del tuyú national park, buenos aires), as well as five domestic ca ...201223060491
characterization of nitric oxide-inducing lipid a derived from mesorhizobium loti lipopolysaccharide.mesorhizobium loti is a member of the rhizobia and forms nitrogen-fixing symbioses with several lotus species. recently, it was reported that m. loti bacterial cells and their lipopolysaccharide (lps) preparations transiently induced nitric oxide (no) production in the roots of l. japonicus. we subsequently found that polysaccharides and the lipid a moiety were responsible for this no induction. in this study, we elucidated the chemical structure of m. loti lipid a and characterized its no-induc ...201223059724
molecular characterization by lssp-pcr and dna sequencing of a pathogenic isolate of leptospira interrogans from brazil.we report the initial characterization of a leptospiral isolate, leptospira interrogans, serogroup sejroe, serovar hardjo, genotype hardjoprajitno, strain norma, and its relatedness with l. interrogans, serogroup sejroe, serovar hardjo, genotype hardjoprajitno, strain hardjo and leptospira borgpetersenii, serogroup sejroe, serovar hardjo, genotype hardjobovis, strain sponselee. the norma strain singled out during a leptospirosis outbreak in cattle immunized with antigens from the reference strai ...201223057087
leptospira interrogans shotgun phage display identified ligb as a heparin-binding protein.ligb is an adhesin from pathogenic leptospira that is able to bind to extracellular matrix and is considered a virulence factor. a shotgun phage display genomic library was constructed and used for panning against heparan sulfate proteoglycan (hspg). a phage clone encoding part of ligb protein was selected in panning experiments and showed specific binding to heparin. to validate the selected clone, fragments of ligb were produced as recombinant proteins and showed affinity to heparin and to mam ...201223044419
the aspergillus fumigatus dihydroxyacid dehydratase ilv3a/ilvc is required for full virulence.dihydroxyacid dehydratase (dhad) is a key enzyme in the branched-chain amino acid biosynthetic pathway that exists in a variety of organisms, including fungi, plants and bacteria, but not humans. in this study we identified four putative dhad genes from the filamentous fungus aspergillus fumigatus by homology to saccharomyces cerevisiae ilv3. two of these genes, afua_2g14210 and afua_1g03550, initially designated afilv3a and afilv3b for this study, clustered in the same group as s. cerevisiae il ...201223028460
a serological survey of leptospiral antibodies in dogs in new zealand.to investigate the prevalence of titres to four endemic leptospiral serovars in dog sera from the lower half of the north island, and the south island of new zealand submitted to diagnostic laboratories, and to explore the association between the prevalence of seropositive samples to leptospirosis and breed group, age group and sex.201323013160
chemotactic behavior of pathogenic and nonpathogenic leptospira species.we have developed a capillary tube assay in combination with real-time pcr to quantitate the number of chemoattracted leptospira cells. we identified tween 80, glucose, sucrose, and pyruvate as attractants for leptospira cells; amino acids and vitamin b(12) were found to be nonchemotactic or weakly chemotactic. this assay has the general applicability to further our understanding of leptospiral chemotaxis.201223001652
[application of multiple-locus variable number tandem repeat analysis (mlva) on molecular typing of leptospira interrogans]. 201022997605
detection of severe fever with thrombocytopenia syndrome virus by reverse transcription-cross-priming amplification coupled with vertical flow visualization.a virus known as severe fever with thrombocytopenia syndrome virus (sftsv) was recently identified as the etiological agent of severe fever with thrombocytopenia syndrome (sfts) in china. reliable laboratory detection and identification of this virus are likely to become clinically and epidemiologically desirable. we developed a nearly instrument-free, simple molecular method which incorporates reverse transcription-cross-priming amplification (rt-cpa) coupled with a vertical flow (vf) visualiza ...201222993179
the ompa family of proteins: roles in bacterial pathogenesis and immunity.the ompa family of outer membrane proteins is a group of genetically related, heat-modifiable, surface-exposed, porin proteins that are in high-copy number in the outer membrane of mainly gram-negative bacteria. ompa proteins are characterized by an n-terminal domain that forms an eight-stranded, anti-parallel β barrel, which is embedded in the outer membrane. the c-terminal domain is globular and located in the periplasmic space. escherichia coli ompa is the best characterized of the proteins. ...201322986056
health assessment and seroepidemiologic survey of potential pathogens in wild antillean manatees (trichechus manatus manatus).the antillean manatee (trichechus manatus manatus), a subspecies of the west indian manatee, inhabits fresh, brackish, and warm coastal waters distributed along the eastern border of central america, the northern coast of south america, and throughout the wider caribbean region. threatened primarily by human encroachment, poaching, and habitat degradation, antillean manatees are listed as endangered by the international union for the conservation of nature. the impact of disease on population vi ...201222984521
quantification of bacterial indicators and zoonotic pathogens in dairy wastewater ponds.zoonotic pathogens in land-applied dairy wastewaters are a potential health risk. the occurrence and abundance of 10 pathogens and 3 fecal indicators were determined by quantitative real-time pcr (qpcr) in samples from 30 dairy wastewaters from southern idaho. samples tested positive for campylobacter jejuni, stx(1)- and eaea-positive escherichia coli, listeria monocytogenes, mycobacterium avium subsp. paratuberculosis, and salmonella enterica, with mean recoveries of genomic dna corresponding t ...201222983964
the future of human dna vaccines.dna vaccines have evolved greatly over the last 20 years since their invention, but have yet to become a competitive alternative to conventional protein or carbohydrate based human vaccines. whilst safety concerns were an initial barrier, the achilles heel of dna vaccines remains their poor immunogenicity when compared to protein vaccines. a wide variety of strategies have been developed to optimize dna vaccine immunogenicity, including codon optimization, genetic adjuvants, electroporation and ...201222981627
leptospiral outer membrane protein microarray, a novel approach to identification of host ligand-binding proteins.leptospirosis is a zoonosis with worldwide distribution caused by pathogenic spirochetes belonging to the genus leptospira. the leptospiral life cycle involves transmission via freshwater and colonization of the renal tubules of their reservoir hosts. infection requires adherence to cell surfaces and extracellular matrix components of host tissues. these host-pathogen interactions involve outer membrane proteins (omps) expressed on the bacterial surface. in this study, we developed an leptospira ...201222961849
protease-dependent mechanisms of complement evasion by bacterial pathogens.the human immune system has evolved a variety of mechanisms for the primary task of neutralizing and eliminating microbial intruders. as the first line of defense, the complement system is responsible for rapid recognition and opsonization of bacteria, presentation to phagocytes and bacterial cell killing by direct lysis. all successful human pathogens have mechanisms of circumventing the antibacterial activity of the complement system and escaping this stage of the immune response. one of the w ...201222944688
leptospira interrogans catalase is required for resistance to h2o2 and for virulence.pathogenic leptospira spp. are likely to encounter higher concentrations of reactive oxygen species induced by the host innate immune response. in this study, we characterized leptospira interrogans catalase (kate), the only annotated catalase found within pathogenic leptospira species, by assessing its role in resistance to h(2)o(2)-induced oxidative stress and during infection in hamsters. pathogenic l. interrogans bacteria had a 50-fold-higher survival rate under h(2)o(2)-induced oxidative st ...201222927050
leptospira spp. strain identification by maldi tof ms is an equivalent tool to 16s rrna gene sequencing and multi locus sequence typing (mlst).in this study mass spectrometry was used for evaluating extracted leptospiral protein samples and results were compared with molecular typing methods. for this, an extraction protocol for leptospira spp. was independently established in two separate laboratories. reference spectra were created with 28 leptospiral strains, including pathogenic, non-pathogenic and intermediate strains. this set of spectra was then evaluated on the basis of measurements with well-defined, cultured leptospiral strai ...201222925589
meta-analysis of general bacterial subclades in whole-genome phylogenies using tree topology profiling.in the last two decades, a large number of whole-genome phylogenies have been inferred to reconstruct the tree of life (tol). underlying data models range from gene or functionality content in species to phylogenetic gene family trees and multiple sequence alignments of concatenated protein sequences. diversity in data models together with the use of different tree reconstruction techniques, disruptive biological effects and the steadily increasing number of genomes have led to a huge diversity ...201222915837
comparative genomics analysis of mycobacterium ulcerans for the identification of putative essential genes and therapeutic candidates.mycobacterium ulcerans, the causative agent of buruli ulcer, is the third most common mycobacterial disease after tuberculosis and leprosy. the present treatment options are limited and emergence of treatment resistant isolates represents a serious concern and a need for better therapeutics. conventional drug discovery methods are time consuming and labor-intensive. unfortunately, the slow growing nature of m. ulcerans in experimental conditions is also a barrier for drug discovery and developme ...201222912793
multiple activities of ligb potentiate virulence of leptospira interrogans: inhibition of alternative and classical pathways of complement.microbial pathogens acquire the immediate imperative to avoid or counteract the formidable defense of innate immunity as soon as they overcome the initial physical barriers of the host. many have adopted the strategy of directly disrupting the complement system through the capture of its components, using proteins on the pathogen's surface. in leptospirosis, pathogenic leptospira spp. are resistant to complement-mediated killing, in contrast to the highly vulnerable non-pathogenic strains. patho ...201222911815
coiled to diffuse: brownian motion of a helical bacterium.we employ real-time three-dimensional confocal microscopy to follow the brownian motion of a fixed helically shaped leptospira interrogans (li) bacterium. we extract from our measurements the translational and the rotational diffusion coefficients of this bacterium. a simple theoretical model is suggested, perfectly reproducing the experimental diffusion coefficients, with no tunable parameters. an older theoretical model, where edge effects are neglected, dramatically underestimates the observe ...201222891749
extreme water-related weather events and waterborne disease.global climate change is expected to affect the frequency, intensity and duration of extreme water-related weather events such as excessive precipitation, floods, and drought. we conducted a systematic review to examine waterborne outbreaks following such events and explored their distribution between the different types of extreme water-related weather events. four medical and meteorological databases (medline, embase, georef, pubmed) and a global electronic reporting system (promed) were searc ...201222877498
extreme water-related weather events and waterborne disease.global climate change is expected to affect the frequency, intensity and duration of extreme water-related weather events such as excessive precipitation, floods, and drought. we conducted a systematic review to examine waterborne outbreaks following such events and explored their distribution between the different types of extreme water-related weather events. four medical and meteorological databases (medline, embase, georef, pubmed) and a global electronic reporting system (promed) were searc ...201222877498
transforming clinical microbiology with bacterial genome sequencing.whole-genome sequencing of bacteria has recently emerged as a cost-effective and convenient approach for addressing many microbiological questions. here, we review the current status of clinical microbiology and how it has already begun to be transformed by using next-generation sequencing. we focus on three essential tasks: identifying the species of an isolate, testing its properties, such as resistance to antibiotics and virulence, and monitoring the emergence and spread of bacterial pathogen ...201222868263
commentary. 201222865993
expression of sialic acids and other nonulosonic acids in leptospira.sialic acids are negatively charged nine carbon backbone sugars expressed on mammalian cell surfaces. sialic acids are part of a larger family of nonulosonic acid (nulo) molecules that includes pseudaminic and legionaminic acids. microbial expression of sialic acids and other nonulosonic acids has been shown to contribute to host-microbe interactions in a variety of contexts, including participation in colonization, immune subversion, and behaviors such as biofilm formation, autoagglutination an ...201222853805
a combined approach of vntr and mlst analysis: improving molecular typing of argentinean isolates of leptospira interrogans.leptospirosis is an emerging infectious disease that has been identified as both a human and animal health problem worldwide. regular outbreaks associated with specific risk factors have been reported in argentina. however, there are no available data concerning the genetic population level for this pathogen. therefore, the aim of this work was to describe the genetic diversity of leptospira interrogans through the application of two molecular typing strategies: variable number of tandem repeats ...201222850955
fatal co-infection--melioidosis and leptospirosis.co-infection of melioidosis and leptospirosis is uncommon. we report here four such cases, confirmed by blood culture for melioidosis and blood polymerase-chain reaction for leptospirosis, which occurred among rescuers involved in a search and rescue operation for a young man who was suspected to have drowned in lubuk yu, a recreational forest in pahang, malaysia. despite treatment, three of the patients died from the co-infection.201222826499
genomic and biochemical analysis of the diaminopimelate and lysine biosynthesis pathway in verrucomicrobium spinosum: identification and partial characterization of l,l-diaminopimelate aminotransferase and udp-n-acetylmuramoylalanyl-d-glutamyl-2,6-meso-diaminopimelate ligase.the gram-negative bacterium verrucomicrobium spinosum has attracted interest in recent years following the sequencing and annotation of its genome. comparative genomic analysis of v. spinosum using diaminopimelate/lysine metabolic genes from chlamydia trachomatis suggests that v. spinosum employs the l,l-diaminopimelate aminotransferase (dapl) pathway for diaminopimelate/lysine biosynthesis. the open reading frame corresponding to the putative dapl ortholog was cloned and the recombinant enzyme ...201222783236
synthesis, leptospirocidal activity and qsar analysis of novel quinoxaline derivatives.a simple and efficient method has been developed for the synthesis of series of n-mannich bases of (e)-3- (phenylimino/4-chlorophenylimino)-2,3-dihydro-1-[(n-substituted piperazinyl) methyl]quinoxaline-2-(1h)-one 3a-f and 4a-f. the requisite 2a and 2b were obtained by reaction between quinoxaline-2,3-dione 1 and aniline/p-chloroaniline. these compounds underwent nmannich reaction with various substituted piperazines to yield (title compounds 3a-f and 4a-f respectively. structures of synthesized ...201322779788
similarities in leptospira serogroup and species distribution in animals and humans in the indian ocean island of mayotte.our objective was to identify local animal reservoirs of leptospirosis to explain the unusual features of leptospira strains recently described among patients on the island of mayotte. by means of a microscopic agglutination test using local clinical isolates, we found that 11.2% of black rats were seropositive to leptospira, whereas 10.2% of flying foxes, 2% of lemurs, 93.1% of domestic dogs, and 87.5% of stray dogs were seropositive. as observed in humans, mini was the main serogroup circulati ...201222764304
phosphate groups of lipid a are essential for salmonella enterica serovar typhimurium virulence and affect innate and adaptive immunity.lipid a is a key component of the outer membrane of gram-negative bacteria and stimulates proinflammatory responses via the toll-like receptor 4 (tlr4)-md2-cd14 pathway. its endotoxic activity depends on the number and length of acyl chains and its phosphorylation state. in salmonella enterica serovar typhimurium, removal of the secondary laurate or myristate chain in lipid a results in bacterial attenuation and growth defects in vitro. however, the roles of the two lipid a phosphate groups in b ...201222753374
lsa30, a novel adhesin of leptospira interrogans binds human plasminogen and the complement regulator c4bp.pathogenic leptospira is the etiological agent of leptospirosis, a life-threatening disease that affects populations worldwide. surface proteins have the potential to promote several activities, including adhesion. this work aimed to study the leptospiral coding sequence (cds) lic11087, genome annotated as hypothetical outer membrane protein. the lic11087 gene was cloned and expressed in escherichia coli bl21 (de3) strain by using the expression vector pae. the recombinant protein tagged with n- ...201222732096
the effect of iron limitation on the transcriptome and proteome of pseudomonas fluorescens pf-5.one of the most important micronutrients for bacterial growth is iron, whose bioavailability in soil is limited. consequently, rhizospheric bacteria such as pseudomonas fluorescens employ a range of mechanisms to acquire or compete for iron. we investigated the transcriptomic and proteomic effects of iron limitation on p. fluorescens pf-5 by employing microarray and itraq techniques, respectively. analysis of this data revealed that genes encoding functions related to iron homeostasis, including ...201222723948
characterization of acetyl-coa and propionyl-coa carboxylases encoded by leptospira interrogans serovar lai: an initial biochemical study for leptospiral gluconeogenesis via anaplerotic co(2) assimilation.leptospira interrogans is the causative agent of leptospirosis. the in vitro growth of l. interrogans requires co(2) and a partial 3-hydroxypropionate pathway involving two acyl-coa carboxylases was suggested by genomic analysis to assimilate co(2). either set of the candidate genes heterologously co-expressed in escherichia coli was able to demonstrate both acetyl-coa carboxylase (acc) and propionyl-coa carboxylase (pcc) activities. the tri-subunit holoenzyme (la_2736-la_2735 and la_3803), alth ...201222710261
reactivity of heat-stable leptospira antigenic preparation used in enzyme-linked immunosorbent assay for detection of antibodies in swine serum.serology plays an important role in laboratory diagnosis of leptospirosis. apart from the most often used microscopic agglutination test (mat), enzyme-linked immunosorbent assay (elisa) seems to be useful especially in screenings of animal herds. the elisa used for detection of antibodies against selected leptospira serogroups in swine serum samples was investigated during the study. an essential element of this test is heat-stable antigenic preparation from cultures of leptospira interrogans se ...201222708354
renal involvement in leptospirosis: the effect of glycolipoprotein on renal water absorption.leptospirotic renal lesions frequently produce a polyuric form of acute kidney injury with a urinary concentration defect. our study investigated a possible effect of the glycolipoprotein, (glpc) extracted from l. interrogans, on vasopressin (vp) action in the guinea pig inner medullary collecting duct (imcd).201222701573
improved adhesive properties of recombinant bifidobacteria expressing the bifidobacterium bifidum-specific lipoprotein bopa.bifidobacteria belong to one of the predominant bacterial groups in the intestinal microbiota of infants and adults. several beneficial effects on the health status of their human hosts have been demonstrated making bifidobacteria interesting candidates for probiotic applications. adhesion of probiotics to the intestinal epithelium is discussed as a prerequisite for colonisation of and persistence in the gastrointestinal tract.201222694891
abc1k atypical kinases in plants: filling the organellar kinase void.surprisingly few protein kinases have been demonstrated in chloroplasts or mitochondria. here, we discuss the activity of bc(1) complex kinase (abc1k) protein family, which we suggest locate in mitochondria and plastids, thus filling the kinase void. the abc1ks are atypical protein kinases and their ancestral function is the regulation of quinone synthesis. abc1ks have proliferated from one or two members in non-photosynthetic organisms to more than 16 members in algae and higher plants. in this ...201222694836
positive regulation of leptospira interrogans kdp expression by kdpe as demonstrated with a novel β-galactosidase reporter in leptospira biflexa.leptospirosis is a potentially deadly zoonotic disease that afflicts humans and animals. leptospira interrogans, the predominant agent of leptospirosis, encounters diverse conditions as it proceeds through its life cycle, which includes stages inside and outside the host. unfortunately, the number of genetic tools available for examining the regulation of gene expression in l. interrogans is limited. consequently, little is known about the genetic circuits that control gene expression in leptosp ...201222685146
leptospirosis in american samoa--estimating and mapping risk using environmental data.the recent emergence of leptospirosis has been linked to many environmental drivers of disease transmission. accurate epidemiological data are lacking because of under-diagnosis, poor laboratory capacity, and inadequate surveillance. predictive risk maps have been produced for many diseases to identify high-risk areas for infection and guide allocation of public health resources, and are particularly useful where disease surveillance is poor. to date, no predictive risk maps have been produced f ...201222666516
stable isotope peptide mass spectrometry to decipher amino acid metabolism in dehalococcoides strain cbdb1.dehalococcoides species are key players in the anaerobic transformation of halogenated solvents at contaminated sites. here, we analyze isotopologue distributions in amino acid pools from peptides of dehalococcoides strain cbdb1 after incubation with (13)c-labeled acetate or bicarbonate as a carbon source. the resulting data were interpreted with regard to genome annotations to identify amino acid biosynthesis pathways. in addition to using gas chromatography-mass spectrometry (gc-ms) for analyz ...201222661690
identification of a novel francisella tularensis factor required for intramacrophage survival and subversion of innate immune response.francisella tularensis, the causative agent of tularemia, is one of the deadliest agents of biological warfare and bioterrorism. extremely high virulence of this bacterium is associated with its ability to dampen or subvert host innate immune response. the objectives of this study were to identify factors and understand the mechanisms of host innate immune evasion by f. tularensis. we identified and explored the pathogenic role of a mutant interrupted at gene locus ftl_0325, which encodes an omp ...201222654100
translational research in infectious disease: current paradigms and challenges ahead.in recent years, the biomedical community has witnessed a rapid scientific and technologic evolution after the development and refinement of high-throughput methodologies. concurrently and consequentially, the scientific perspective has changed from the reductionist approach of meticulously analyzing the fine details of a single component of biology to the "holistic" approach of broadmindedly examining the globally interacting elements of biological systems. the emergence of this new way of thin ...201222633095
molecular and serological characterization of leptospira interrogans serovar canicola isolated from dogs, swine, and bovine in brazil.the identification of leptospira clinical isolates through genotyping and serotyping, besides the recognition of its reservoirs, are important tools for understanding the epidemiology of leptospirosis, and they are also keys for identifying new species and serovars. fourteen clinical isolates from animals were characterized by means of single enzyme amplified length polymorphism, variable number of tandem repeat analysis, pulsed field gel electrophoresis, and serotyping. all isolates were identi ...201322610538
predicting antigenicity of proteins in a bacterial proteome; a protein microarray and naïve bayes classification approach.discovery of novel antigens associated with infectious diseases is fundamental to the development of serodiagnostic tests and protein subunit vaccines against existing and emerging pathogens. efforts to predict antigenicity have relied on a few computational algorithms predicting signal peptide sequences (signalp), transmembrane domains, or subcellular localization (psort). an empirical protein microarray approach was developed to scan the entire proteome of any infectious microorganism and empi ...201222589097
structure, function and inhibition of the two- and three-domain 4fe-4s ispg proteins.ispg is a 4fe4s protein involved in isoprenoid biosynthesis. most bacterial ispgs contain two domains: a tim barrel (a) and a 4fe4s domain (b), but in plants and malaria parasites, there is a large insert domain (a*) whose structure and function are unknown. we show that bacterial ispgs function in solution as (ab)(2) dimers and that mutations in either both a or both b domains block activity. chimeras harboring an a-mutation in one chain and a b-mutation in the other have 50% of the activity se ...201222586085
an assessment of current bioinformatic solutions for analyzing lc-ms data acquired by selected reaction monitoring technology.selected reaction monitoring (srm) is an accurate quantitative technique, typically used for small-molecule mass spectrometry (ms). srm has emerged as an important technique for targeted and hypothesis-driven proteomic research, and is becoming the reference method for protein quantification in complex biological samples. srm offers high selectivity, a lower limit of detection and improved reproducibility, compared to conventional shot-gun-based tandem ms (lc-ms/ms) methods. unlike lc-ms/ms, whi ...201222577019
using irt, a normalized retention time for more targeted measurement of peptides.multiple reaction monitoring (mrm) has recently become the method of choice for targeted quantitative measurement of proteins using mass spectrometry. the method, however, is limited in the number of peptides that can be measured in one run. this number can be markedly increased by scheduling the acquisition if the accurate retention time (rt) of each peptide is known. here we present irt, an empirically derived dimensionless peptide-specific value that allows for highly accurate rt prediction. ...201222577012
urine as a specimen to diagnose infections in twenty-first century: focus on analytical accuracy.urine as a clinical specimen to diagnose infections has been used since ancient times. many rapid technologies to assist diagnosis of infections are currently in use. alongside traditional enzyme immunoassays (eia), new technologies have emerged. molecular analysis of transrenal dna to diagnose infections is also a rapidly growing field. the majority of eias utilize the detection of excreted sugar compounds of the outer microbial cell-wall shed into the bloodstream and excreted into the urine. t ...201222566927
interaction of human complement factor h variants tyr⁴⁰² and his⁴⁰² with leptospira spp.leptospirosis is a zoonosis caused by pathogenic bacteria from the genus leptospira. the disease represents a serious public health problem in underdeveloped tropical countries. leptospires infect hosts through small abrasions in the skin or mucous membranes and they rapidly disseminate to target organs. the capacity of some pathogenic leptospiral strains to acquire the negative complement regulators factor h (fh) and c4b binding protein correlates with their ability to survive in human serum. i ...201122566834
comparing the similarity of different groups of bacteria to the human proteome.numerous aspects of the relationship between bacteria and human have been investigated. one aspect that has recently received attention is sequence overlap at the proteomic level. however, there has not yet been a study that comprehensively characterizes the level of sequence overlap between bacteria and human, especially as it relates to bacterial characteristics like pathogenicity, g-c content, and proteome size. in this study, we began by performing a general characterization of the range of ...201222558081
seroprevalence of leptospira hardjo in the irish suckler cattle population.prior to the present study, the seroprevalence of leptospirosis in irish suckler herds was unknown. in this study, we describe the herd and animal-level prevalence of leptospira hardjo infection in the irish suckler cattle population. for the purposes of the study, the 26 counties of the republic of ireland were divided into 6 regions from which a representative number of herds were selected. a herd was considered eligible for sampling if it was not vaccinating against leptospirosis and if it co ...201222546216
activity and crystal structure of arabidopsis thaliana udp-n-acetylglucosamine acyltransferase.the udp-n-acetylglucosamine (udp-glcnac) acyltransferase, encoded by lpxa, catalyzes the first step of lipid a biosynthesis in gram-negative bacteria, the (r)-3-hydroxyacyl-acp-dependent acylation of the 3-oh group of udp-glcnac. recently, we demonstrated that the arabidopsis thaliana orthologs of six enzymes of the bacterial lipid a pathway produce lipid a precursors with structures similar to those of escherichia coli lipid a precursors [li, c., et al. (2011) proc. natl. acad. sci. u.s.a. 108, ...201222545860
predicting the outer membrane proteome of pasteurella multocida based on consensus prediction enhanced by results integration and manual confirmation.outer membrane proteins (omps) of pasteurella multocida have various functions related to virulence and pathogenesis and represent important targets for vaccine development. various bioinformatic algorithms can predict outer membrane localization and discriminate omps by structure or function. the designation of a confident prediction framework by integrating different predictors followed by consensus prediction, results integration and manual confirmation will improve the prediction of the oute ...201222540951
efficacy of vaccination of cattle with the leptospira interrogans serovar hardjo type hardjoprajitno component of a pentavalent leptospira bacterin against experimental challenge with leptospira borgpetersenii serovar hardjo type hardjo-bovis.to evaluate the efficacy of vaccination with the leptospira interrogans serovar hardjo type hardjoprajitno component of a pentavalent leptospira bacterin against a virulent experimental challenge with leptospira borgpetersenii serovar hardjo type hardjo-bovis strain 203 in cattle.201222533408
longitudinal serological survey and herd-level risk factors for leptospira spp. serovars hardjo-bovis and pomona on deer farms with sheep and/or beef cattle.to investigate the seroprevalence of leptospira spp. serovars hardjo-bovis and pomona on deer and mixed deer, sheep and/or beef cattle farms in the lower north island of new zealand and to examine associations between putative risk factors for seropositive deer herds.201222506918
genome signature difference between deinococcus radiodurans and thermus thermophilus.the extremely radioresistant bacteria of the genus deinococcus and the extremely thermophilic bacteria of the genus thermus belong to a common taxonomic group. considering the distinct living environments of deinococcus and thermus, different genes would have been acquired through horizontal gene transfer after their divergence from a common ancestor. their guanine-cytosine (gc) contents are similar; however, we hypothesized that their genomic signatures would be different. our findings indicate ...201222500246
group a streptococcus secreted esterase hydrolyzes platelet-activating factor to impede neutrophil recruitment and facilitate innate immune evasion.the innate immune system is the first line of host defense against invading organisms. thus, pathogens have developed virulence mechanisms to evade the innate immune system. here, we report a novel means for inhibition of neutrophil recruitment by group a streptococcus (gas). deletion of the secreted esterase gene (designated sse) in m1t1 gas strains with (mgas5005) and without (mgas2221) a null covs mutation enhances neutrophil ingress to infection sites in the skin of mice. in trans expression ...201222496650
prevalence of antibody to six leptospira servovars in swedish wild boars.zoonotic leptospira bacteria are pathogens that may increase in importance with climate change. we investigated the prevalence of antibody to six leptospira serovars (sv) in the swedish wild boar (sus scrofa) population, which is increasing in number and geographic distribution. the serovars we selected cause disease in pigs or may be of use as sentinel serovars to measure the potential spread in swedish fauna. in total, 386 serum samples from wild boars collected between 2005 and 2007 were inve ...201222493129
features of two proteins of leptospira interrogans with potential role in host-pathogen interactions.leptospirosis is considered a re-emerging infectious disease caused by pathogenic spirochaetes of the genus leptospira. pathogenic leptospires have the ability to survive and disseminate to multiple organs after penetrating the host. leptospires were shown to express surface proteins that interact with the extracellular matrix (ecm) and to plasminogen (plg). this study examined the interaction of two putative leptospiral proteins with laminin, collagen type i, collagen type iv, cellular fibronec ...201222463075
the major facilitator superfamily (mfs) revisited.the major facilitator superfamily (mfs) is the largest known superfamily of secondary carriers found in the biosphere. it is ubiquitously distributed throughout virtually all currently recognized organismal phyla. this superfamily currently (2012) consists of 74 families, each of which is usually concerned with the transport of a certain type of substrate. many of these families, defined phylogenetically, do not include even a single member that is functionally characterized. in this article, we ...201222458847
flaa proteins in leptospira interrogans are essential for motility and virulence but are not required for formation of the flagellum sheath.spirochetes have periplasmic flagella composed of a core surrounded by a sheath. the pathogen leptospira interrogans has four flab (proposed core subunit) and two flaa (proposed sheath subunit) genes. the flaa genes are organized in a locus with flaa2 immediately upstream of flaa1. in this study, flaa1 and flaa2 mutants were constructed by transposon mutagenesis. both mutants still produced periplasmic flagella. the flaa1 mutant did not produce flaa1 but continued to produce flaa2 and retained n ...201222451522
herd-level risk factors associated with leptospira hardjo seroprevalence in beef/suckler herds in the republic of ireland.the aim of the present study was to investigate risk factors for herd seropositivity to leptospira hardjo in irish suckler herds. herds were considered eligible for the study if they were unvaccinated and contained ≥ 9 breeding animals of beef breed which were ≥ 12 months of age. the country was divided into six regions using county boundaries. herd and individual animal prevalence data were available from the results of a concurrent seroprevalence study. herds were classified as either "free fr ...201222449264
recovery of leptospires from miniature pigs experimentally infected with leptospira interrogans serovar manilae strain up-mmc under immunosuppressive conditions by dexamethasone.leptospira interrogans serovar manilae strain up-mmc was inoculated into miniature pigs to assess its pathogenicity. leptospires were recovered from the whole blood, kidneys, and livers in the acute phase without showing any clinical signs. under immunosuppressive conditions by dexamethasone, leptospires were recovered from the kidneys and their genes were detected from the urine in the chronic phase. these results indicate that leptospires persisted in the kidneys until the chronic phase, and e ...201222446397
structural analysis of the leptospiral sphingomyelinases: in silico and experimental evaluation of sph2 as an mg-dependent sphingomyelinase.leptospiral sphingomyelinases are candidate virulence factors present only in pathogenic leptospira spp. leptospira interrogans serovar lai encodes sph1, sph2, sph3, sph4 and sphh. except for sph4, they all possess the exo-endo-phosphatase domain that groups them under the dnase i superfamily.201222441407
evaluation and comparison of native and recombinant lipl21 protein-based elisas for diagnosis of bovine leptospirosis.a 21-kda leptospiral lipoprotein (lipl21) was evaluated for its diagnostic potential to detect bovine leptospirosis by elisa. both native lipl21 (nlipl21) and recombinant lipl21 (rlipl21) proteins were tested and compared regarding diagnostic efficiency, and no statistically significant difference was observed. the sensitivity of rlipl21 elisa for 62 microscopic agglutination test (mat) positive sera was 100% and the specificity with 378 mat negative sera was 97.09%. thus, rlipl21 protein-based ...201222437542
functional epitope core motif of the anaplasma marginale major surface protein 1a and its incorporation onto bioelectrodes for antibody detection.anaplasmosis, a persistent intraerythrocytic infection of cattle by anaplasma marginale, causes severe anemia and a higher rate of abortion, resulting in significant loss to both dairy and beef industries. clinical diagnosis is based on symptoms and confirmatory laboratory tests are required. currently, all the diagnostic assays have been developed with whole antigens with indirect elisa based on multiple epitopes. in a pioneer investigation we demonstrated the use of critical motifs of an epito ...201222427942
multiple leptospiral sphingomyelinases (or are there?).culture supernatants of leptospiral pathogens have long been known to haemolyse erythrocytes. this property is due, at least in part, to sphingomyelinase activity. indeed, genome sequencing reveals that pathogenic leptospira species are richly endowed with sphingomyelinase homologues: five genes have been annotated to encode sphingomyelinases in leptospira interrogans. such redundancy suggests that this class of genes is likely to benefit leptospiral pathogens in their interactions with the mamm ...201222422753
high-throughput subtomogram alignment and classification by fourier space constrained fast volumetric matching.cryo-electron tomography allows the visualization of macromolecular complexes in their cellular environments in close-to-live conditions. the nominal resolution of subtomograms can be significantly increased when individual subtomograms of the same kind are aligned and averaged. a vital step for such a procedure are algorithms that speedup subtomogram alignment and improve its accuracy to allow reference-free subtomogram classifications. such methods will facilitate automation of tomography anal ...201222420977
a comparative analysis of the attachment of leptospira interrogans and l. borgpetersenii to mammalian cells.leptospirosis, the world's most ubiquitous zoonosis, is caused by pathogenic leptospira. as microbe-host interactions are specific in pathogenesis, it is likely that there are several molecules mediating the attachment of the leptospira to mammalian cells. in this study, we analysed the attachment of leptospira interrogans serovar portlandvere and leptospira borgpetersenii serovar jules to untreated hep-2 cells or hep-2 cells treated with the various enzymes, lectins or sugars and to integrins α ...201222409511
antigen-specific t cells and cytokines detection as useful tool for understanding immunity against zoonotic infections.zoonoses include a broad range of diseases, that are becoming of great interest, due to the climate changing, that cause the adaptation of vectors to new niches and environments. host immune responses play a crucial role in determining the outcome of infections, as documented by expansion of antigen-specific t cells during several zoonotic infections. thus, understanding of the contribution of antigen-specific t-cell subsets in the host immune response is a powerful tool to evaluate the differen ...201222400039
detection and quantification of leptospira interrogans in hamster and rat kidney samples: immunofluorescent imprints versus real-time pcr.a major limitation in the clinical management and experimental research of leptospirosis is the poor performance of the available methods for the direct detection of leptospires. in this study, we compared real-time pcr (qpcr), targeting the lipl32 gene, with the immunofluorescent imprint method (im) for the detection and quantification of leptospires in kidney samples from the rat and hamster experimental models of leptospirosis. using a virulent strain of leptospira interrogans serovar copenha ...201222393440
the prevalence of leptospiral antibodies in free roaming cats in worcester county, massachusetts.serosurveys of cats for exposure to or infection with leptospires have been published from other geographic areas, but none for cats in the united states in the past 4 decades.201622390370
rapid maldi-tof mass spectrometry identification of leptospira organisms.leptospirosis is a worldwide deadly zoonotic disease. accurate identification of the causative leptospira spp. spirochetes ascertains the pathogenic status of the isolates, identifies potential source of infection and recognises outbreaks. species identification is currently based on technically demanding, time and resources consuming serological and molecular methods. matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof-ms) recently emerged as a first-line met ...201222386673
protection against lethal leptospirosis after vaccination with lipl32 coupled or coadministered with the b subunit of escherichia coli heat-labile enterotoxin.leptospirosis, a worldwide zoonosis, lacks an effective, safe, and cross-protective vaccine. lipl32, the most abundant, immunogenic, and conserved surface lipoprotein present in all pathogenic species of leptospira, is a promising antigen candidate for a recombinant vaccine. however, several studies have reported a lack of protection when this protein is used as a subunit vaccine. in an attempt to enhance the immune response, we used lipl32 coupled to or coadministered with the b subunit of the ...201222379066
utility of quantitative polymerase chain reaction in leptospirosis diagnosis: association of level of leptospiremia and clinical manifestations in sri lanka.quantitative polymerase chain reaction (qpcr), despite cost and logistical challenges, has the potential to provide accurate and timely diagnosis for leptospirosis at the point-of-care in endemic areas. we studied optimal sample types for qpcr, timing of sampling, and clinical manifestations in relation to quantitative leptospiremia.201222354922
evaluation of pathogenic serovars of leptospira interrogans in dairy cattle herds of shahrekord by pcr.leptospirosis is an important zoonotic disease caused by leptospira interrogans. leptospirosis leads to economical losses in dairy farm industry. the objective of this study was to evaluate the pathogenic serovars of leptospira interrogans in dairy cattle herds of shahrekord by pcr.201122347596
leptospire genomic diversity revealed by microarray-based comparative genomic hybridization.comparative genomic hybridization was used to compare genetic diversity of five strains of leptospira (leptospira interrogans serovars bratislava, canicola, and hebdomadis and leptospira kirschneri serovars cynopteri and grippotyphosa). the array was designed based on two available sequenced leptospira reference genomes, those of l. interrogans serovar copenhageni and l. interrogans serovar lai. a comparison of genetic contents showed that l. interrogans serovar bratislava was closest to the ref ...201222344655
induction of tnf-alfa and cxcl-2 mrnas in different organs of mice infected with pathogenic leptospira.the role of innate immune response in protection against leptospirosis is poorly understood. we examined the expression of the chemokine cxcl2/mip-2 and the cytokine tnf-α in experimental resistant and susceptible mice models, c3h/hej, c3h/hepas and balb/c strains, using a virulent strain of leptospira interrogans serovar copenhageni. animals were infected intraperitoneally with 10(7) cells and the development of the disease was followed. mortality of c3h/hej mice was observed whereas c3h/hepas ...201222342618
the mammalian cell entry (mce) protein of pathogenic leptospira species is responsible for rgd motif-dependent infection of cells and animals.mammalian cell entry proteins (mces) contribute to mycobacterium tuberculosis virulence. a mce homologue has been identified in the leptospira interrogans genome, but its function was unknown. we showed that the mce gene is expressed only by pathogenic leptospira strains tested. leptospiral mce mrna and mce protein levels increased during infection of macrophages. the ability to infect macrophages was significantly lower in a strain with the mce gene deleted (mce(-) ). complementation of the mce ...201222329803
analysis of multiple leptospira interrogans serovar canicola vaccine proteomes and identification of lipl32 as a biomarker for potency.the current batch potency test for leptospira interrogans serovar canicola vaccines requires the use of a large number of hamsters and has severe effects (i.e., hepatic and renal failure resulting in death); while this vaccine is effective, a safer, cheaper, more ethical replacement is desired. the aim of this study was to analyze vaccine proteomes and identify target molecules common to all l. interrogans serovar canicola vaccines which could be used to design an in vitro potency test. initial ...201222323560
downregulation of the na/k-atpase pump by leptospiral glycolipoprotein activates the nlrp3 inflammasome.leptospira interrogans is responsible for a zoonotic disease known to induce severe kidney dysfunction and inflammation. in this work, we demonstrate that l. interrogans induces nlrp3 inflammasome-dependent secretion of il-1β through the alteration of potassium transport in bone marrow-derived macrophages. lysosome destabilization also contributed to the il-1β production upon stimulation with live, but not dead, bacteria. using bone marrow-derived macrophages from various tlrs and nucleotide-bin ...201222323544
in silico analysis of a therapeutic target in leishmania infantum: the guanosine-diphospho-d-mannose pyrophosphorylase.leishmaniases are tropical and sub-tropical diseases for which classical drugs (i.e. antimonials) exhibit toxicity and drug resistance. such a situation requires to find new chemical series with antileishmanial activity. this work consists in analyzing the structure of a validated target in leishmania: the gdp-mannose pyrophosphorylase (gdp-mp), an enzyme involved in glycosylation and essential for amastigote survival. by comparing both human and l. infantum gdp-mp 3d homology models, we identif ...201222314241
Refresh
firstprev
12345678910...
nextlast
Displaying items 701 - 800 of 2728