Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
a computational study of elongation factor g (efg) duplicated genes: diverged nature underlying the innovation on the same structural template.elongation factor g (efg) is a core translational protein that catalyzes the elongation and recycling phases of translation. a more complex picture of efg's evolution and function than previously accepted is emerging from analyzes of heterogeneous efg family members. whereas the gene duplication is postulated to be a prominent factor creating functional novelty, the striking divergence between efg paralogs can be interpreted in terms of innovation in gene function.201121829651
human leptospira isolates circulating in mayotte (indian ocean) have unique serological and molecular features.leptospirosis is one of the most widespread zoonoses in the world. however, there is a lack of information on leptospira circulating strains in remote parts of the world. we describe the serological and molecular features of leptospires isolated from 94 leptospirosis patients in mayotte, a french department located in the comoros archipelago, between 2007 and 2010. multilocus sequence typing identified these isolates as l. interrogans, l. kirschneri, l. borgpetersenii, and a previously undefined ...201122162544
the antibacterial activity of ll-37 against treponema denticola is dentilisin-protease independent and facilitated by the major outer sheath protein virulence factor.host defense peptides are innate immunoeffectors that possess both bactericidal activities and immunomodulatory functions. deficiency in the human ll-37 host defense peptide has been previously correlated with severe periodontal disease. treponema denticola is an oral anaerobic spirochete closely associated with the pathogenesis of periodontal disease. the t. denticola major surface protein (msp), involved in adhesion and in cytotoxicity, and the dentilisin serine protease are key virulence fact ...201122184422
comparative proteomic analysis of differentially expressed proteins in the urine of reservoir hosts of leptospirosis.rattus norvegicus is a natural reservoir host for pathogenic species of leptospira. experimentally infected rats remain clinically normal, yet persistently excrete large numbers of leptospires from colonized renal tubules via urine, despite a specific host immune response. whilst persistent renal colonization and shedding is facilitated in part by differential antigen expression by leptospires to evade host immune responses, there is limited understanding of kidney and urinary proteins expressed ...201122043303
survey of leptospira spp in pampas deer (ozotoceros bezoarticus) in the pantanal wetlands of the state of mato grosso do sul, brazil by serology and polymerase chain reaction.this work reports a survey of leptospira spp in pampas deer (ozotoceros bezoarticus) in the pantanal wetlands of the state of mato grosso do sul, brazil by serology and polymerase chain reaction (pcr). seventy pampas deer were captured in the dry season and surveyed using pcr, microscopic agglutination test (mat) (n = 51) and by both techniques (n = 47). pcr detected infections in two pampas deer and mat detected infections in three. through sequencing and phylogenetic analyses, the pcr-amplifie ...201122012234
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
helicobacter pylori versus the host: remodeling of the bacterial outer membrane is required for survival in the gastric mucosa.modification of bacterial surface structures, such as the lipid a portion of lipopolysaccharide (lps), is used by many pathogenic bacteria to help evade the host innate immune response. helicobacter pylori, a gram-negative bacterium capable of chronic colonization of the human stomach, modifies its lipid a by removal of phosphate groups from the 1- and 4'-positions of the lipid a backbone. in this study, we identify the enzyme responsible for dephosphorylation of the lipid a 4'-phosphate group i ...201122216004
detection of leptospiral antibodies by microscopic agglutination test in north-east of iran.to detect leptospiral antibodies by microscopic agglutination test (mat) in north-east of iran.201123569764
estimation of absolute protein quantities of unlabeled samples by selected reaction monitoring mass spectrometry.for many research questions in modern molecular and systems biology information about absolute protein quantities is imperative. these include, for example, kinetic modeling of processes, protein turnover determinations, stoichiometric investigations of protein complexes or quantitative comparisons of different proteins within one or across samples. to date, the vast majority of proteomic studies are limited to providing relative quantitative comparisons of protein levels between limited numbers ...201122101334
methylation and in vivo expression of the surface-exposed leptospira interrogans outer membrane protein ompl32.recent studies have revealed that bacterial protein methylation is a widespread post-translational modification that is required for virulence in selected pathogenic bacteria. in particular, altered methylation of outer membrane proteins has been shown to modulate the effectiveness of the host immune response. in this study, two-dimensional gel electrophoresis combined with matrix-assisted laser desorption/ionization-time of flight mass spectrometry identified a leptospira interrogans serovar c ...201122174381
annotation of protein domains reveals remarkable conservation in the functional make up of proteomes across superkingdoms.the functional repertoire of a cell is largely embodied in its proteome, the collection of proteins encoded in the genome of an organism. the molecular functions of proteins are the direct consequence of their structure and structure can be inferred from sequence using hidden markov models of structural recognition. here we analyze the functional annotation of protein domain structures in almost a thousand sequenced genomes, exploring the functional and structural diversity of proteomes. we find ...201124710297
rodent abundance dynamics and leptospirosis carriage in an area of hyper-endemicity in new caledonia.widespread but particularly incident in the tropics, leptospirosis is transmitted to humans directly or indirectly by virtually any mammal species. however, rodents are recognized as the most important reservoir. in endemic regions, seasonal outbreaks are observed during hot rainy periods. in such regions, hot spots can be evidenced, where leptospirosis is "hyper-endemic", its incidence reaching 500 annual cases per 100,000. a better knowledge of how rodent populations and their leptospira preva ...201122039557
leptospirosis prevalence in chinese populations in the last two decades.leptospirosis is a common zoonotic disease in china. from 1991 to 2010, its average annual incidence was 0.70 cases per 100,000 population. during these two decades, three major outbreaks of leptospirosis occurred due to flooding and heavy rainfall. leptospira interrogans serogroup icterohaemorrhagiae serovar lai is the predominant leptospire responsible for at least 60% of chinese cases, and apodemus agrarius serves as the major animal host. based on the differences in predominant leptospiral s ...201122155621
Monoclonal antibodies against the leptospiral immunoglobulin-like proteins A and B conserved regions.Leptospirosis is an infectious disease caused by pathogenic spirochetes of the genus Leptospira that affects humans and a wide variety of animals. Recently the genomes of Leptospira interrogans, Leptospira borgpetersenii and Leptospira biflexa species were sequenced allowing the identification of new virulence factors involved in survival and pathogenesis of bacteria. LigA and LigB are surface-exposed bacterial adhesins whose expression is correlated with the virulence of Leptospira strains. In ...201121903270
Subunit approach to evaluation of the immune protective potential of leptospiral antigens.Leptospirosis is the most widespread zoonosis in the world. Current vaccines are based on whole-cell preparations that cause severe side effects and do not induce satisfactory immunity. In light of the leptospiral genome sequences recently made available, several studies aimed at identification of protective recombinant immunogens have been performed; however, few such immunogens have been identified. The aim of this study was to evaluate 27 recombinant antigens to determine their potential to i ...201122030369
cholinesterases as markers of the inflammatory process in rats infected with leptospira interrogans serovar icterohaemorrhagiae.the aim of this study was evaluate changes in the cholinesterase activity in blood, lymphocytes and serum of rats infected with leptospira interrogans serovar icterohaemorrhagiae ('l. icterohaemorrhagiae'). sixty adult wistar rats were divided into six groups of 10 animals: three control groups and three test groups. the animals from the test groups were intraperitoneally inoculated with 1 ml medium containing 1×10(8) leptospires. the activity of acetylcholinesterase in blood and butyrylcholines ...201121921108
Communicable diseases prioritized for surveillance and epidemiological research: results of a standardized prioritization procedure in Germany, 2011.To establish strategic priorities for the German national public health institute (RKI) and guide the institute's mid-term strategic decisions, we prioritized infectious pathogens in accordance with their importance for national surveillance and epidemiological research.201121991334
functional promiscuity of the cog0720 family.the biosynthesis of gtp derived metabolites such as tetrahydrofolate (thf), biopterin (bh(4)), and the modified trna nucleosides queuosine (q) and archaeosine (g(+)) relies on several enzymes of the tunnel-fold superfamily. a subset of these proteins includes the 6-pyruvoyltetrahydropterin (ptps-ii), ptps-iii, and ptps-i homologues, all members of the cog0720 family that have been previously shown to transform 7,8-dihydroneopterin triphosphate (h(2)ntp) into different products. ptps-ii catalyzes ...201121999246
functional promiscuity of the cog0720 family.the biosynthesis of gtp derived metabolites such as tetrahydrofolate (thf), biopterin (bh(4)), and the modified trna nucleosides queuosine (q) and archaeosine (g(+)) relies on several enzymes of the tunnel-fold superfamily. a subset of these proteins includes the 6-pyruvoyltetrahydropterin (ptps-ii), ptps-iii, and ptps-i homologues, all members of the cog0720 family that have been previously shown to transform 7,8-dihydroneopterin triphosphate (h(2)ntp) into different products. ptps-ii catalyzes ...201121999246
The Fate of Glucose-1-Phosphate into Oligo and Polysaccharides in Streptomyces coelicolor: Characterization of recombinant UDP- and ADP-glucose pyrophosphorylases and of glycogen synthase.Streptomyces coelicolor exhibits a major secondary metabolism, deriving important amounts of glucose to synthesize pigmented antibiotics. Understanding the pathways occurring in the bacterium with respect to synthesis of oligo and polysaccharides is of relevance to figure out a real scenario on the partitioning of glucose-1-phosphate into different metabolic fates. We report the molecular cloning of the genes coding for UDP- and ADP-glucose pyrophosphorylases as well as for glycogen synthase fro ...201122210767
Outbreak of leptospirosis among triathlon participants in Langau, Austria, 2010.We report on the first documented outbreak of leptospirosis in Austria. In July 2010, four cases of serologically confirmed leptospirosis occurred in athletes after a triathlon held in Langau. Heavy rains preceded the triathlon (rainfall: 22 mm). The index case (Patient A) was a 41-year-old previously healthy male, who was admitted to hospital A on July 8 with a four-day history of fever up to 40°C that began 14 days after attending the triathlon event. On July 7, patient B, a 42-year-old male, ...201122105111
a liga three-domain region protects hamsters from lethal infection by leptospira interrogans.the leptospiral liga protein consists of 13 bacterial immunoglobulin-like (big) domains and is the only purified recombinant subunit vaccine that has been demonstrated to protect against lethal challenge by a clinical isolate of leptospira interrogans in the hamster model of leptospirosis. we determined the minimum number and location of liga domains required for immunoprotection. immunization with domains 11 and 12 was found to be required but insufficient for protection. inclusion of a third d ...201122180800
effects of recent leptospira vaccination on whole blood real-time pcr testing in healthy client-owned dogs.bacterin-based canine leptospira vaccines could present a challenge for the use of whole blood real-time polymerase chain reaction (pcr) as a diagnostic tool. recent vaccination could induce positive results if the targeted dna fragment is present within the vaccine and in the blood of the recently vaccinated dog.201122182214
A phylometagenomic exploration of oceanic alphaproteobacteria reveals mitochondrial relatives unrelated to the SAR11 clade.According to the endosymbiont hypothesis, the mitochondrial system for aerobic respiration was derived from an ancestral Alphaproteobacterium. Phylogenetic studies indicate that the mitochondrial ancestor is most closely related to the Rickettsiales. Recently, it was suggested that Candidatus Pelagibacter ubique, a member of the SAR11 clade that is highly abundant in the oceans, is a sister taxon to the mitochondrial-Rickettsiales clade. The availability of ocean metagenome data substantially in ...201121935411
cloning, expression, and homology modeling of groel protein from leptospira interrogans serovar autumnalis strain n2.leptospirosis is an infectious bacterial disease caused by leptospira species. in this study, we cloned and sequenced the gene encoding the immunodominant protein groel from l. interrogans serovar autumnalis strain n2, which was isolated from the urine of a patient during an outbreak of leptospirosis in chennai, india. this groel gene encodes a protein of 60 kda with a high degree of homology (99% similarity) to those of other leptospiral serovars. recombinant groel was overexpressed in escheric ...201122196358
a highly stable plastidic-type ferredoxin-nadp(h) reductase in the pathogenic bacterium leptospira interrogans.leptospira interrogans is a bacterium that is capable of infecting animals and humans, and its infection causes leptospirosis with a range of symptoms from flu-like to severe illness and death. despite being a bacteria, leptospira interrogans contains a plastidic class ferredoxin-nadp(h) reductase (fnr) with high catalytic efficiency, at difference from the bacterial class fnrs. these flavoenzymes catalyze the electron transfer between nadp(h) and ferredoxins or flavodoxins. the inclusion of a p ...201122039544
the quantitative proteome of a human cell line.the generation of mathematical models of biological processes, the simulation of these processes under different conditions, and the comparison and integration of multiple data sets are explicit goals of systems biology that require the knowledge of the absolute quantity of the system's components. to date, systematic estimates of cellular protein concentrations have been exceptionally scarce. here, we provide a quantitative description of the proteome of a commonly used human cell line in two f ...201122068332
mite allergen der-p2 triggers human b lymphocyte activation and toll-like receptor-4 induction.allergic disease can be characterized as manifestations of an exaggerated inflammatory response to environmental allergens triggers. mite allergen der-p2 is one of the major allergens of the house dust mite, which contributes to tlr4 expression and function in b cells in allergic patients. however, the precise mechanisms of der-p2 on b cells remain obscure.201121909400
amino acid features of p1b-atpase heavy metal transporters enabling small numbers of organisms to cope with heavy metal pollution.phytoremediation refers to the use of plants for extraction and detoxification of pollutants, providing a new and powerful weapon against a polluted environment. in some plants, such as thlaspi spp, heavy metal atpases are involved in overall metal ion homeostasis and hyperaccumulation. p1b-atpases pump a wide range of cations, especially heavy metals, across membranes against their electrochemical gradients. determination of the protein characteristics of p1b-atpases in hyperaccumulator plants ...201121573033
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
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
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
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
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
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
A Surface Enolase Participates in Borrelia burgdorferi-Plasminogen Interaction and Contributes to Pathogen Survival within Feeding Ticks.Borrelia burgdorferi, a tick-borne bacterial pathogen, causes a disseminated infection involving multiple organs known as Lyme disease. Surface proteins can directly participate in microbial virulence by facilitating pathogen dissemination via interaction with host factors. We show here that a fraction of the B. burgdorferi chromosomal gene product BB0337, annotated as enolase or phosphopyruvate dehydratase, is associated with spirochete outer membrane and is surface exposed. B. burgdorferi enol ...201222025510
three-dimensional structures of pathogenic and saprophytic leptospira revealed by cryo-electron tomography.leptospira interrogans is the primary causative agent of the most widespread zoonotic disease, leptospirosis. an in-depth structural characterization of l. interrogans is needed to understand its biology and pathogenesis. in this study, cryo-electron tomography (cryo-et) was used to compare pathogenic and saprophytic species and examine the unique morphological features of this group of bacteria. specifically, our study revealed a structural difference between the cell envelopes of l. interrogan ...201222228733
establishment of a leptospirosis model in guinea pigs using an epicutaneous inoculations route.abstract: background: leptospires are presumed to enter their host via small abrasions or breaches of the skin. the intraperitoneal route, although commonly used in guinea pig and hamster models of leptospirosis, does not reflect conditions encountered during natural infection. the aim of this study is to develop a novel leptospirosis guinea pig model through epicutaneous route and to elucidate the pathogenesis of leptospirosis in experimental guinea pigs by comparing the data from other studie ...201222273178
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
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
seroprevalence of leptospirosis in dogs in urban harare and selected rural communities in zimbabwe.a cross-sectional study was conducted to investigate seroprevalence of canine leptospirosis in urban harare and five selected rural communities in zimbabwe and to assess public awareness of the disease. sera from randomly selected dogs were tested for antibodies to the serovars canicola, grippotyphosa, icterohaemorrhagiae and pomona of leptospira interrogans using an enzyme-linked immunosorbent assay. clinical chemistry was performed on all seropositive and selected seronegative sera to screen f ...201223327324
immunoproteomics: the key to discovery of new vaccine antigens against bacterial respiratory infections.the increase in antibiotic resistance and the shortage of new antimicrobials to prevent difficult bacterial infections underlines the importance of prophylactic therapies to prevent infection by bacterial pathogens. vaccination has reduced the incidence of many serious diseases, including respiratory bacterial infections. however, there are many pathogens for which no vaccine is available and some vaccines are not effective among all age groups or among immunocompromised individuals. immunoprote ...201223305366
comparative seroprevalence of leptospira interrogans in colombian mammals along a climatic gradient.leptospirosis is a widespread zoonotic disease with well-established impacts on human health in tropical and subtropical regions. although leptospira spp. are known to readily infect many wildlife species, the understanding of interspecies and climatic variability in patterns of infection in neotropical mammals is limited. to improve the understanding of this interplay, 85 mammals representing 17 species were sampled from four colombian zoos along a climatic gradient. prevalence of the 21 primar ...201223272343
molecular and serological investigation of leptospira and leptospirosis in dogs in japan.canine leptospirosis, which is caused by infection with pathogenic leptospira species, occurs worldwide, but information regarding the causative leptospira serotypes and genotypes and their effects on virulence in dogs remains limited. monitoring acute leptospirosis in dogs as sentinels can also aid in estimating the risk of human leptospirosis, particularly when the disease is rare, as it currently is in japan. among 283 clinically suspected cases of leptospirosis diagnosed from august 2007 to ...201223264455
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
identification of novel dna-binding proteins using dna-affinity chromatography/pull down.this units presents methods through which one may isolate and identify novel bacterial dna-binding proteins. briefly, the dna sequence of interest is affixed to beads, and then incubated with bacterial cytoplasmic extract. washes with buffers containing nonspecific dna and low-salt concentrations will remove non-adhering and low-specificity dna-binding proteins, while subsequent washes with higher salt concentrations will elute more specific dna-binding proteins. eluted proteins may then be iden ...201222307548
serum antibodies to whole-cell and recombinant antigens of borrelia burgdorferi in cottontail rabbits.archived serum samples, from 95 eastern cottontail rabbits (sylvilagus floridanus) captured in new york, new york, usa and millbrook, new york, usa, during 1985-86, were analyzed in solid-phase enzyme-linked immunosorbent assays (elisa) for total and class-specific immunoglobulin (ig) m antibodies to whole-cell or recombinant antigens of borrelia burgdorferi sensu stricto. using a polyvalent conjugate, rabbit sera contained antibodies to whole-cell and recombinant antigens (protein [p]35, p37, o ...201222247369
growth response and shedding of leptospira spp. in urine following vaccination for leptospirosis in young farmed deer.abstract201222175424
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
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
comparison of two pcr methods for detection of leptospira interrogans in formalin-fixed and paraffin-embedded tissues.in this study we compared two polymerase chain reaction (pcr) methods using either 16s ribosomal rna (rrna) or 23s rrna gene primers for the detection of different leptospira interrogans serovars. the performance of these two methods was assessed using dna extracted from bovine tissues previously inoculated with several bacterial suspensions. pcr was performed on the same tissues before and after the formalin-fixed, paraffin-embedding procedure (ffpe tissues). the 23s rdna pcr detected all fresh ...201222310540
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
a novel tetravalent leptospira bacterin protects against infection and shedding following challenge in dogs.recent evidence based on the current epidemiological situation suggests that vaccines against canine leptospirosis in europe should be directed against infection with leptospira interrogans (sensu lato) serogroups canicola, icterohaemorrhagiae, grippotyphosa and australis. in the eight studies presented here, dogs were vaccinated with nobivac l4 (msd animal health), a new tetravalent inactivated vaccine containing antigen from four strains representing these four serogroups. the dogs were then c ...201223180149
a novel tetravalent leptospira bacterin protects against infection and shedding following challenge in dogs.recent evidence based on the current epidemiological situation suggests that vaccines against canine leptospirosis in europe should be directed against infection with leptospira interrogans (sensu lato) serogroups canicola, icterohaemorrhagiae, grippotyphosa and australis. in the eight studies presented here, dogs were vaccinated with nobivac l4 (msd animal health), a new tetravalent inactivated vaccine containing antigen from four strains representing these four serogroups. the dogs were then c ...201223180149
structure determination of lpxa from the lipopolysaccharide-synthesis pathway of acinetobacter baumannii.acinetobacter baumannii is a gram-negative pathogenic bacterium which is resistant to most currently available antibiotics and that poses a significant health threat to hospital patients. lpxa is a key enzyme in the biosynthetic pathway of the lipopolysaccharides that are components of the bacterial outer membrane. it is a potential target for antibacterial agents that might be used to fight a. baumannii infections. this paper describes the structure determination of the apo form of lpxa in spac ...201223192027
serosurveillance for livestock pathogens in free-ranging mule deer (odocoileus hemionus).routine disease surveillance has been conducted for decades in mule deer (odocoileus hemionus) in california for pathogens shared between wildlife and domestic ruminants that may have implications for the animal production industry and wildlife health. deer sampled from 1990 to 2007 (n = 2,619) were tested for exposure to six pathogens: bluetongue virus (btv), epizootic hemorrhagic disease virus (ehdv), bovine viral diarrhea virus (bvdv), leptospira spp., anaplasma spp. and brucella spp. we eval ...201223209790
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
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
leptospirosis outbreaks in nicaragua: identifying critical areas and exploring drivers for evidence-based planning.leptospirosis is an epidemic-prone zoonotic disease that occurs worldwide. in central america, leptospirosis outbreaks have been reported in almost all countries; nicaragua in particular has faced several outbreaks. the objective of this study was to stratify the risk and identify "critical areas" for leptospirosis outbreaks in nicaragua, and to perform an exploratory analysis of potential "drivers". this ecological study includes the entire country (153 municipalities). cases from 2004 to 2010 ...201223202822
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
evaluation of immunoprotective activity of six leptospiral proteins in the hamster model of leptospirosis.leptospirosis is a worldwide zoonosis caused by pathogenic leptospira. the whole-genome sequence of l. interrogans serovar copenhageni together with bioinformatics tools represent a great opportunity to search for novel antigen candidates that could be used as subunit vaccine against leptospirosis. we focused on six genes encoding for conserved hypothetical proteins predicted to be exported to the outer membrane. the genes were amplified by pcr from leptospira interrogans genomic dna and were cl ...201223173023
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
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
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
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
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
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
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
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
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
Refresh
firstprev
...11121314151617181920...
nextlast
Displaying items 1901 - 2000 of 2728