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clocking the lyme spirochete.in order to clear the body of infecting spirochetes, phagocytic cells must be able to get hold of them. in real-time phase-contrast videomicroscopy we were able to measure the speed of borrelia burgdorferi (bb), the lyme spirochete, moving back and forth across a platelet to which it was tethered. its mean crossing speed was 1,636 microm/min (n = 28), maximum, 2800 microm/min (n = 3). this is the fastest speed recorded for a spirochete, and upward of two orders of magnitude above the speed of a ...200818286190
serological survey of canine leptospirosis in the tropics of yucatan mexico using two different tests.blood samples were taken from 400 stray dogs. the microscopic agglutination test (mat) and enzyme-linked immunosorbent assay (elisa) test were implemented using leptospira interrogans serogroups canicola, hardjo, pyrogenes, panama, pomona, tarassovi, icterohaemorrhagiae, gryppotyphosa, wolffi and brastislava. for the elisa test, sonicated antigen from above mentioned cultures was used. a conjugate ap-labeled anti-dog igg antibody was used, the optimal cut-off point of elisa was set at 1.34. conc ...200818299115
reliability and applications of statistical methods based on oligonucleotide frequencies in bacterial and archaeal genomes.the increasing number of sequenced prokaryotic genomes contains a wealth of genomic data that needs to be effectively analysed. a set of statistical tools exists for such analysis, but their strengths and weaknesses have not been fully explored. the statistical methods we are concerned with here are mainly used to examine similarities between archaeal and bacterial dna from different genomes. these methods compare observed genomic frequencies of fixed-sized oligonucleotides with expected values, ...200818307761
biochemical and phylogenetic characterization of a novel diaminopimelate biosynthesis pathway in prokaryotes identifies a diverged form of ll-diaminopimelate aminotransferase.a variant of the diaminopimelate (dap)-lysine biosynthesis pathway uses an ll-dap aminotransferase (dapl, ec 2.6.1.83) to catalyze the direct conversion of l-2,3,4,5-tetrahydrodipicolinate to ll-dap. comparative genomic analysis and experimental verification of dapl candidates revealed the existence of two diverged forms of dapl (dapl1 and dapl2). dapl orthologs were identified in eubacteria and archaea. in some species the corresponding dapl gene was found to lie in genomic contiguity with othe ...200818310350
cytotoxic activity and probable apoptotic effect of sph2, a sphigomyelinase hemolysin from leptospira interrogans strain lai.our previous work confirmed that sph2/la1029 was a sphigomyelinase-like hemolyisn of leptospira interrogans serogroup icterohaemorrhagiae serovar lai. characteristics of both hemolytic and cytotoxic activities of sph2 were reported in this paper. sph2 was a heat-labile neutral hemolysin and had similar hemolytic behavior as the typical sphingomyelinase c of staphylococcus aureus upon sheep erythrocytes. the cytotoxic activity of sph2 was shown in mammalian cells such as balb/c mouse lymphocytes ...200818315947
cohesion group approach for evolutionary analysis of tyra, a protein family with wide-ranging substrate specificities.many enzymes and other proteins are difficult subjects for bioinformatic analysis because they exhibit variant catalytic, structural, regulatory, and fusion mode features within a protein family whose sequences are not highly conserved. however, such features reflect dynamic and interesting scenarios of evolutionary importance. the value of experimental data obtained from individual organisms is instantly magnified to the extent that given features of the experimental organism can be projected u ...200818322033
leptospirosis-associated severe pulmonary hemorrhagic syndrome, salvador, brazil.we report the emergence of leptospirosis-associated severe pulmonary hemorrhagic syndrome (sphs) in slum communities in salvador, brazil. although active surveillance did not identify sphs before 2003, 47 cases were identified from 2003 through 2005; the case-fatality rate was 74%. by 2005, sphs caused 55% of the deaths due to leptospirosis.200818325275
a novel gdp-dependent pyruvate kinase isozyme from toxoplasma gondii localizes to both the apicoplast and the mitochondrion.we previously reported a cytosolic pyruvate kinase (ec 2.7.1.40) from toxoplasma gondii (tgpyki) that differs from most eukaryotic pyruvate kinases in being regulated by glucose 6-phosphate rather than fructose 1,6-diphosphate. another putative pyruvate kinase (tgpykii) was identified from parasite genome, which exhibits 32% amino acid sequence identity to tgpyki and retains pyruvate kinase signature motifs and amino acids essential for substrate binding and catalysis. whereas tgpyki is most clo ...200818326043
leptospirosis: clinical presentation and correlation with serovars.a total of 2400 patients with pyrexia of unknown origin and or suspected leptospirosis were included in this study. dark field microscopy detected leptospira in 690 cases, leptospira serological investigations proved positive in 570 out of these 690 patients. among them 212 had the classical icteric and the other 358 had anicteric type of presentation. notably eptospira interrogans serovar ictero haemorrhagiae infection was encountered in 212 patients. in 30 patients, who had multi organ dysfunc ...200718338689
selection of the internal control gene for real-time quantitative rt-pcr assays in temperature treated leptospira.analysis of gene expression requires sensitive, precise, and reproducible measurements for specific mrna sequences. to avoid bias, real-time rt-pcr is referred to one or several internal control genes. here, we sought to identify a gene to be used as normalizer by analyzing three functional distinct housekeeping genes (lipl41, flab, and 16s rrna) for their expression level and stability in temperature treated leptospira cultures. leptospira interrogans serovar hardjo subtype hardjoprajitno was c ...200818347854
household transmission of leptospira infection in urban slum communities.leptospirosis, a spirochaetal zoonotic disease, is the cause of epidemics associated with high mortality in urban slum communities. infection with pathogenic leptospira occurs during environmental exposures and is traditionally associated with occupational risk activities. however, slum inhabitants reside in close proximity to environmental sources of contamination, suggesting that transmission during urban epidemics occurs in the household environment.200818357340
identification of a novel prophage-like gene cluster actively expressed in both virulent and avirulent strains of leptospira interrogans serovar lai.dna microarray analysis was used to compare the differential gene expression profiles between leptospira interrogans serovar lai type strain 56601 and its corresponding attenuated strain ipav. a 22-kb genomic island covering a cluster of 34 genes (i.e., genes la0186 to la0219) was actively expressed in both strains but concomitantly upregulated in strain 56601 in contrast to that of ipav. reverse transcription-pcr assays proved that the gene cluster comprised five transcripts. gene annotation of ...200818362131
detection of pathogenic leptospira bacteria in pinniped populations via pcr and identification of a source of transmission for zoonotic leptospirosis in the marine environment.leptospirosis, caused by the spirochete leptospira, is a geographically widespread disease that affects a broad range of mammals, including marine mammals. among pinniped populations, periodic epizootics of leptospirosis are responsible for significant die-offs. along the west coast of north america, the most recent leptospirosis epizootic occurred in 2004, during which samples were collected from cases ranging from california to british columbia. the primary objective of this study was to use t ...200818367568
vitamin k-dependent carboxylation.vitamin k-dependent (vkd) protein carboxylation uses vitamin k epoxidation to convert glus to carboxylated glus (glas), rendering vkd proteins active in physiologies that include hemostasis, apoptosis, bone mineralization, calcium homeostasis, growth control, and signal transduction. clusters of glus are modified by a processive carboxylase, generating a calcium-binding module that allows binding to either hydroxyapatite in the extracellular matrices or cell surfaces where anionic phospholipids ...200818374193
sodium chloride affects helicobacter pylori growth and gene expression.epidemiological evidence links high-salt diets and helicobacter pylori infection with increased risk of developing gastric maladies. the mechanism by which elevated sodium chloride content causes these manifestations is unclear. here we characterize the response of h. pylori to temporal changes in sodium chloride concentration and show that growth, cell morphology, survival, and virulence factor expression are all altered by increased salt concentration.200818375562
human leptospirosis caused by a new, antigenically unique leptospira associated with a rattus species reservoir in the peruvian amazon.as part of a prospective study of leptospirosis and biodiversity of leptospira in the peruvian amazon, a new leptospira species was isolated from humans with acute febrile illness. field trapping identified this leptospire in peridomestic rats (rattus norvegicus, six isolates; r. rattus, two isolates) obtained in urban, peri-urban, and rural areas of the iquitos region. novelty of this species was proven by serological typing, 16s ribosomal rna gene sequencing, pulsed-field gel electrophoresis, ...200818382606
highly conserved surface proteins of oral spirochetes as adhesins and potent inducers of proinflammatory and osteoclastogenic factors.oral spirochetes include enormously heterogeneous treponema species, and some have been implicated in the etiology of periodontitis. in this study, we characterized highly conserved surface proteins in four representative oral spirochetes (treponema denticola, t. lecithinolyticum, t. maltophilum, and t. socranskii subsp. socranskii) that are homologs of t. pallidum tp92, with opsonophagocytic potential and protective capacity against syphilis. tp92 homologs of oral spirochetes had predicted sign ...200818390996
in lipl32, the major leptospiral lipoprotein, the c terminus is the primary immunogenic domain and mediates interaction with collagen iv and plasma fibronectin.lipl32 is the major leptospiral outer membrane lipoprotein expressed during infection and is the immunodominant antigen recognized during the humoral immune response to leptospirosis in humans. in this study, we investigated novel aspects of lipl32. in order to define the immunodominant domains(s) of the molecule, subfragments corresponding to the n-terminal, intermediate, and c-terminal portions of the lipl32 gene were cloned and the proteins were expressed and purified by metal affinity chroma ...200818391007
lrua and lrub antibodies in sera of humans with leptospiral uveitis.uveitis can be a serious complication of leptospirosis. previous studies indicated that the leptospiral lipoproteins lrua and lrub are expressed in the eyes of uveitic horses and that antibodies directed against those proteins show in vitro cross-reactivity with components of equine lens, ciliary body, and/or retina. we now demonstrate that sera from a significant proportion of humans who have leptospiral uveitis also contain antibodies against lrua and lrub. different categories of nonleptospir ...200818400972
antimicrobial susceptibilities of geographically diverse clinical human isolates of leptospira.although antimicrobial therapy of leptospirosis has been studied in a few randomized controlled clinical studies, those studies were limited to specific regions of the world and few have characterized infecting strains. a broth microdilution technique for the assessment of antibiotic susceptibility has been developed at brooke army medical center. in the present study, we assessed the susceptibilities of 13 leptospira isolates (including recent clinical isolates) from egypt, thailand, nicaragua, ...200818411316
genome-wide subcellular localization of putative outer membrane and extracellular proteins in leptospira interrogans serovar lai genome using bioinformatics approaches.in bacterial pathogens, both cell surface-exposed outer membrane proteins and proteins secreted into the extracellular environment play crucial roles in host-pathogen interaction and pathogenesis. considerable efforts have been made to identify outer membrane (om) and extracellular (ex) proteins produced by leptospira interrogans, which may be used as novel targets for the development of infection markers and leptospirosis vaccines.200818423054
development and experimental validation of a predictive threshold cycle equation for quantification of virulence and marker genes by high-throughput nanoliter-volume pcr on the openarray platform.development of quantitative pcr (qpcr) assays typically requires extensive screening within and across a given species to ensure specific detection and lucid identification among various pathogenic and nonpathogenic strains and to generate standard curves. to minimize screening requirements, multiple virulence and marker genes (vmgs) were targeted simultaneously to enhance reliability, and a predictive threshold cycle (c(t)) equation was developed to calculate the number of starting copies based ...200818424532
impact of environment and social gradient on leptospira infection in urban slums.leptospirosis has become an urban health problem as slum settlements have expanded worldwide. efforts to identify interventions for urban leptospirosis have been hampered by the lack of population-based information on leptospira transmission determinants. the aim of the study was to estimate the prevalence of leptospira infection and identify risk factors for infection in the urban slum setting.200818431445
severe course of rat bite-associated weil's disease in a patient diagnosed with a new leptospira-specific real-time quantitative lux-pcr.leptospirosis is a zoonotic disease with global distribution, caused by spirochaetes of the genus leptospira. transmission of leptospira interrogans serovar icterohaemorrhagiae, the causative agent of weil's disease, to humans usually results from exposure to the urine of infected, but mostly asymptomatic, rodents, either by direct contact or indirectly through contaminated soil or water. although regarded as a re-emerging infectious disease, human leptospirosis is probably underdiagnosed due to ...200818436602
lsa21, a novel leptospiral protein binding adhesive matrix molecules and present during human infection.it has been well documented over past decades that interaction of pathogens with the extracellular matrix (ecm) plays a primary role in host cell attachment and invasion. adherence to host tissues is mediated by surface-exposed proteins expressed by the microorganisms during infection. the mechanisms by which pathogenic leptospires invade and colonize the host remain poorly understood since few virulence factors contributing to the pathogenesis of the disease have been identified. whole-genome s ...200818445272
biology of infection with borrelia burgdorferi.the spirochete borrelia burgdorferi is a tick-borne obligate parasite whose normal reservoir is a variety of small mammals. although infection of these natural hosts does not lead to disease, infection of humans can result in lyme disease as a consequence of the human immunopathologic response to b burgdorferi. consistent with the pathogenesis of lyme disease, bacterial products that allow b burgdorferi to replicate and survive seem to be primarily what is required for the bacterium to cause dis ...200818452798
acyl chain specificity of the acyltransferases lpxa and lpxd and substrate availability contribute to lipid a fatty acid heterogeneity in porphyromonas gingivalis.porphyromonas gingivalis lipid a is heterogeneous with regard to the number, type, and placement of fatty acids. analysis of lipid a by matrix-assisted laser desorption ionization-time of flight mass spectrometry reveals clusters of peaks differing by 14 mass units indicative of an altered distribution of the fatty acids generating different lipid a structures. to examine whether the transfer of hydroxy fatty acids with different chain lengths could account for the clustering of lipid a structur ...200818456814
a genome-wide proteome array reveals a limited set of immunogens in natural infections of humans and white-footed mice with borrelia burgdorferi.humans and other animals with lyme borreliosis produce antibodies to a number of components of the agent borrelia burgdorferi, but a full accounting of the immunogens during natural infections has not been achieved. employing a protein array produced in vitro from 1,292 dna fragments representing approximately 80% of the genome, we compared the antibody reactivities of sera from patients with early or later lyme borreliosis to the antibody reactivities of sera from controls. overall, approximate ...200818474646
a 52-kda leucyl aminopeptidase from treponema denticola is a cysteinylglycinase that mediates the second step of glutathione metabolism.the metabolism of glutathione by the periodontal pathogen treponema denticola produces hydrogen sulfide, which may play a role in the host tissue destruction seen in periodontitis. h2s production in this organism has been proposed to occur via a three enzyme pathway, gamma-glutamyltransferase, cysteinylglycinase (cgase), and cystalysin. in this study, we describe the purification and characterization of t. denticola cgase. standard approaches were used to purify a 52-kda cgase activity from t. d ...200818482986
unraveling the evolutionary history of the phosphoryl-transfer chain of the phosphoenolpyruvate:phosphotransferase system through phylogenetic analyses and genome context.the phosphoenolpyruvate phosphotransferase system (pts) plays a major role in sugar transport and in the regulation of essential physiological processes in many bacteria. the pts couples solute transport to its phosphorylation at the expense of phosphoenolpyruvate (pep) and it consists of general cytoplasmic phosphoryl transfer proteins and specific enzyme ii complexes which catalyze the uptake and phosphorylation of solutes. previous studies have suggested that the evolution of the constituents ...200818485189
molecular basis of the substrate specificity and the catalytic mechanism of citramalate synthase from leptospira interrogans.leptospira interrogans is the causative agent for leptospirosis, a zoonotic disease of global importance. in contrast with most other micro-organisms, l. interrogans employs a pyruvate pathway to synthesize isoleucine and licms (l. interrogans citramalate synthase) catalyses the first reaction of the pathway which converts pyruvate and acetyl-coa into citramalate, thus making it an attractive target for the development of antibacterial agents. we report here the crystal structures of the catalyt ...200818498255
serological survey for evidence of leptospira interrogans in free-living platypuses (ornithorhynchus anatinus).to survey free-living platypuses for evidence of leptospira interrogans.200818498563
functional and structural characterization of a cation-dependent o-methyltransferase from the cyanobacterium synechocystis sp. strain pcc 6803.the coding sequence of the cyanobacterium synechocystis sp. strain pcc 6803 slr0095 gene was cloned and functionally expressed in escherichia coli. the corresponding enzyme was classified as a cation- and s-adenosyl-l-methionine-dependent o-methyltransferase (synomt), consistent with considerable amino acid sequence identities to eukaryotic o-methyltransferases (omts). the substrate specificity of synomt was similar with those of plant and mammalian ccoaomt-like proteins accepting a variety of h ...200818502765
the leptospiral antigen lp49 is a two-domain protein with putative protein binding function.pathogenic leptospira is the etiological agent of leptospirosis, a life-threatening disease that affects populations worldwide. currently available vaccines have limited effectiveness and therapeutic interventions are complicated by the difficulty in making an early diagnosis of leptospirosis. the genome of leptospira interrogans was recently sequenced and comparative genomic analysis contributed to the identification of surface antigens, potential candidates for development of new vaccines and ...200818508281
human granulocytic ehrlichiosis complicating early pregnancy.background: the goal of this case is to review the zoonotic infection, human granulocytic ehrlichiosis, presenting with pyrexia. case. a 22-year-old multigravid female presented to the emergency department with a painful skin rash, high fever, and severe myalgias. the patient underwent a diagnostic evaluation for zoonotic infections due to her geographical and seasonal risk factors. treatment of human granulocytic ehrlichiosis was successful though the patient spontaneously aborted presumably du ...200818509484
leptospira interrogans requires a functional heme oxygenase to scavenge iron from hemoglobin.the transposon tnsc189 was used to construct a mutant in the putative heme oxygenase gene hemo (lb186) of leptospira interrogans. unlike its parent strain, the mutant grew poorly in medium in which hemoglobin was the sole iron source. the putative heme oxygenase was over expressed in a his-tagged form, purified and was demonstrated to degrade heme in vitro. unexpectedly, it was also found that the l. interrogans growth rate was significantly increased when medium was supplemented with hemoglobin ...200818524663
characterization of the antioxidant enzyme, thioredoxin peroxidase, from the carcinogenic human liver fluke, opisthorchis viverrini.the human liver fluke, opisthorchis viverrini, induces inflammation of the hepatobiliary system. despite being constantly exposed to inimical oxygen radicals released from inflammatory cells, the parasite survives for many years. the mechanisms by which it avoids oxidative damage are unknown. in this study, thioredoxin peroxidase (tpx), a member of the peroxiredoxin superfamily, was cloned from an o. viverrini cdna library. o. viverrini tpx cdna encoded a polypeptide of 212 amino acid residues, ...200818538872
characterization of virulence of leptospira isolates in a hamster model.effort has been made to identify protective antigens in order to develop a recombinant vaccine against leptospirosis. several attempts failed to conclusively demonstrate efficacy of vaccine candidates due to the lack of an appropriate model of lethal leptospirosis. the purposes of our study were: (i) to test the virulence of leptospiral isolates from brazil, which are representative of important serogroups that cause disease in humans and animals; and (ii) to standardize the lethal dose 50% (ld( ...200818547690
disease threats to the endangered iberian lynx (lynx pardinus).the iberian lynx, (lynx pardinus), is the most endangered felid in the world. to determine whether sympatric carnivores are reservoirs of pathogens posing a disease risk for the lynx, evidence of exposure to 17 viral, bacterial and protozoan agents was investigated in 176 carnivores comprising 26 free-living lynx, 53 domestic cats, 28 dogs, 33 red foxes (vulpes vulpes), 24 egyptian mongooses (herpestes ichneumon), 10 common genets (genetta genetta) and 2 eurasian badgers (meles meles) in the are ...200918555712
leptospira interrogans is recognized through dc-sign and induces maturation and cytokine production by human dendritic cells.leptospirosis is a global zoonotic disease, caused by pathogenic leptospira species including leptospira interrogans, that causes public health and livestock problems. pathogenesis, immune response and cellular receptors for leptospira are not well understood. interaction of dendritic cells (dcs) with l. interrogans serovar autumnalis l-643 and bl-6 isolated from leptospirosis patients, and both virulent and avirulent serovar pyrogenes 2317 strains isolated from animal were investigated. carbohy ...200818564288
real-time high resolution 3d imaging of the lyme disease spirochete adhering to and escaping from the vasculature of a living host.pathogenic spirochetes are bacteria that cause a number of emerging and re-emerging diseases worldwide, including syphilis, leptospirosis, relapsing fever, and lyme borreliosis. they navigate efficiently through dense extracellular matrix and cross the blood-brain barrier by unknown mechanisms. due to their slender morphology, spirochetes are difficult to visualize by standard light microscopy, impeding studies of their behavior in situ. we engineered a fluorescent infectious strain of borrelia ...200818566656
how can infectious diseases be prioritized in public health? a standardized prioritization scheme for discussion. 200818578019
automated discovery and phylogenetic analysis of new toxin-antitoxin systems.although often viewed as elements "at the service of" bacteria, plasmids exhibit replication and maintenance mechanisms that make them purely "selfish dna" candidates. toxin-antitoxin (ta) systems are a spectacular example of such mechanisms: a gene coding for a cytotoxic stable protein is preceded by a gene coding for an unstable antitoxin. the toxin being more stable than the antitoxin, absence of the operon causes a reduction of the amount of the latter relative to the amount of the former. t ...200818578869
conservation of the s10-spc-alpha locus within otherwise highly plastic genomes provides phylogenetic insight into the genus leptospira.s10-spc-alpha is a 17.5 kb cluster of 32 genes encoding ribosomal proteins. this locus has an unusual composition and organization in leptospira interrogans. we demonstrate the highly conserved nature of this region among diverse leptospira and show its utility as a phylogenetically informative region. comparative analyses were performed by pcr using primer sets covering the whole locus. correctly sized fragments were obtained by pcr from all l. interrogans strains tested for each primer set ind ...200818648538
characterization of new is elements and studies of their dispersion in two subspecies of leifsonia xyli.leifsonia xyli is a xylem-inhabiting bacterial species comprised of two subspecies: l. xyli subsp. xyli (lxx) and l. xyli subsp. cynodontis (lxc). lxx is the causal agent of ratoon stunting disease in sugarcane commercial fields and lxc colonizes the xylem of several grasses causing either mild or no symptoms of disease. the completely sequenced genome of lxx provided insights into its biology and pathogenicity. since is elements are largely reported as an important source of bacterial genome di ...200818655699
cross-sectional study of canine leptospirosis in animal shelter populations in mainland australia.to measure the prevalence of canine leptospirosis in queensland and to detect infection, if present, in new south wales, victoria, south australia, western australia and the northern territory by measuring the serological titres of dogs held in animal shelters.200818673473
prevalence of pathogenic leptospira spp. in sheep in a sheep-only abattoir in new zealand.to determine the prevalence of the two most commonly diagnosed pathogenic leptospira spp. serovars, hardjobovis and pomona, in sheep in a sheep-only abattoir in new zealand, and to determine the prevalence of kidneys which were leptospire culture-positive collected from sheep seropositive or seronegative to the microscopic agglutination test (mat).200818690252
diagnostic potential of an iron-regulated hemin-binding protein hbpa that is widely conserved in leptospira interrogans.like most bacteria, leptospira spp. requires iron for growth. however, they face conditions of iron limitation due to the low solubility of the ferric iron and additionally due to the observation that most of the available iron is held as protein-bound iron by the mammalian host. our experimental observations with pathogenic leptospira showed that they do not elaborate siderophores upon iron limitation. in leptospira interrogans serovar lai, we demonstrated direct acquisition of iron via an iron ...200818692158
bacterial species exhibit diversity in their mechanisms and capacity for protein disulfide bond formation.protein disulfide bond formation contributes to the folding and activity of many exported proteins in bacteria. however, information about disulfide bond formation is limited to only a few bacterial species. we used a multifaceted bioinformatic approach to assess the capacity for disulfide bond formation across this biologically diverse group of organisms. we combined data from a cysteine counting method, in which a significant bias for even numbers of cysteine in proteins is taken as an indicat ...200818695247
[zoonoses transmitted by mouse and rat maintained as laboratory or pet animals].large numbers of mice (mus spp.) and rats (rattus spp.) are maintained for scientific reasons and as pet animals in germany. while laboratory animals are monitored for pathogenic agents, the hygienic status of pet animals is usually completely unknown. despite great efforts, zoonotic infections were reported even in laboratory settings, e.g. with hantavirus (seoul virus), streptobacillus moniliformis, and trichphyton mentagrophytes. however, in current reports, zoonotic infections were transmitt ...200818712260
carriage of leptospira interrogans among domestic rats from an urban setting highly endemic for leptospirosis in brazil.a survey was conducted to identify reservoirs for urban leptospirosis in the city of salvador, brazil. sampling protocols were performed in the vicinity of households of severe leptospirosis cases identified during active hospital-based surveillance. among a total of 142 captured rattus norvegicus (norwegian brown rat), 80.3% had a positive culture isolate from urine or kidney specimens and 68.1% had a positive serum sample by microscopic agglutination test (mat) titre of > or = 1:100. monoclona ...200818721789
the guinea pig as a model of infectious diseases.the words 'guinea pig' are synonymous with scientific experimentation, but much less is known about this species than many other laboratory animals. this animal model has been used for approximately 200 y and was the first to be used in the study of infectious diseases such as tuberculosis and diphtheria. today the guinea pig is used as a model for a number of infectious bacterial diseases, including pulmonary, sexually transmitted, ocular and aural, gastrointestinal, and other infections that t ...200818724774
proteomic analysis of leptospira interrogans shed in urine of chronically infected hosts.leptospirosis is a global zoonotic disease. the causative agent, pathogenic leptospira species, survives in the renal tubules of chronically infected hosts, from where leptospires are shed via urine into the environment. infection of new hosts can present as an array of acute and chronic disease processes reflecting variations in host-pathogen interactions. the present study was designed to reproduce the carrier phase of infection in rattus norvegicus, thus facilitating shedding of leptospires i ...200818765721
hamster model of leptospirosis.this unit describes the techniques involved in the hamster model of leptospirosis. hamsters are exquisitely susceptible to infection with pathogenic leptospira species. the ld(50) of virulent leptospiral strains by intraperitoneal inoculation of 3- to 4-week-old hamsters is as low as a single organism. the pathogenesis of severe leptospirosis in the hamster is a model of accidental infections observed in nature in many mammals, including humans. animal husbandry issues and the reproducibility of ...200618770576
putative outer membrane proteins of leptospira interrogans stimulate human umbilical vein endothelial cells (huvecs) and express during infection.cell adhesion molecules (cams) are surface receptors present in eukaryotic cells that mediate cell-cell or cell-extracellular matrix interactions. vascular endothelium stimulation in vitro that lead to the upregulation of cams was reported for the pathogenic spirochaetes, including rlic10365 of leptospira interrogans. in this study, we report the cloning of lic10507, lic10508, lic10509 genes of l. interrogans using escherichia coli as a host system. the rational for selecting these sequences is ...200818778767
toll-like receptors in skin infections and inflammatory diseases.the skin is the ultimate example of the function of innate immunity, it alerts the host of danger by many systems including sensing pathogen-associated molecule patterns (pamps) through toll-like receptors and other pattern recognition receptors (prrs), yet normally provides defense without inflammation. the skin responds rapidly to invading microbes by producing antimicrobial peptides or other antimicrobial intermediates before cytokine release results in inflammation. to achieve maximal immune ...200818782031
evaluation of leptospiral recombinant antigens mpl17 and mpl21 for serological diagnosis of leptospirosis by enzyme-linked immunosorbent assays.leptospirosis is a zoonosis of multisystem involvement caused by pathogenic strains of the genus leptospira. in the last few years, intensive studies aimed at the development of a vaccine have provided important knowledge about the nature of the immunological mechanisms of the host. the purpose of this study was to analyze the immune responses to two recombinant proteins, mpl17 and mpl21 (encoded by the genes lic10765 and lic13131, respectively) of leptospira interrogans serovar copenhageni in i ...200818799647
synthetic tetra-acylated derivatives of lipid a from porphyromonas gingivalis are antagonists of human tlr4.tetra-acylated lipid as derived from porphyromonas gingivalis lps have been synthesized using a key disaccharide intermediate functionalized with levulinate (lev), allyloxycarbonate (alloc) and anomeric dimethylthexylsilyl (tds) as orthogonal protecting groups and 9-fluorenylmethoxycarbamate (fmoc) and azido as amino protecting groups. furthermore, an efficient cross-metathesis has been employed for the preparation of the unusual branched r-(3)-hydroxy-13-methyltetradecanic acid and (r)-3-hexade ...200818802645
the genome of rhodobacter sphaeroides strain 2.4.1 encodes functional cobinamide salvaging systems of archaeal and bacterial origins.bacteria and archaea use distinct pathways for salvaging exogenous cobinamide (cbi), a precursor of adenosylcobalamin (coenzyme b(12)). the bacterial pathway depends on a bifunctional enzyme with kinase and guanylyltransferase activities (cobp in aerobic adenosylcobalamin synthesizers) to convert adenosylcobinamide (adocbi) to adocbi-guanosine diphosphate (adocbi-gdp) via an adocbi-phosphate intermediate. archaea lack cobp, and use a different strategy for the synthesis of adocbi-gdp. archaea cl ...200818808385
targeted mutagenesis in pathogenic leptospira species: disruption of the ligb gene does not affect virulence in animal models of leptospirosis.the pathogenic mechanisms of leptospira interrogans, the causal agent of leptospirosis, remain largely unknown. this is mainly due to the lack of tools for genetically manipulating pathogenic leptospira species. thus, homologous recombination between introduced dna and the corresponding chromosomal locus has never been demonstrated for this pathogen. leptospiral immunoglobulin-like repeat (lig) proteins were previously identified as putative leptospira virulence factors. in this study, a ligb mu ...200818809657
an insect symbiosis is influenced by bacterium-specific polymorphisms in outer-membrane protein a.beneficial bacterial symbioses are ubiquitous in nature. however, the functional and molecular basis of host tolerance to resident symbiotic microbes, in contrast to resistance to closely related bacteria that are recognized as foreign, remain largely unknown. we used the tsetse fly (glossina morsitans), which depends on symbiotic flora for fecundity and has limited exposure to foreign microbes, to investigate the tolerance phenomenon exhibited during symbiosis. we examined the potential role of ...200818815366
recombinant multiepitope protein for diagnosis of leptospirosis.leptospirosis is an emerging infectious disease and is considered to be the most widespread zoonotic disease in the world. it can be misdiagnosed because manifestations of this febrile disease vary from mild flu-like symptoms to severe illness involving vital organs such as the liver and lungs. therefore, accurate diagnosis for differentiation of leptospirosis from other pyrogenic infections prevailing in the same locality is imperative for proper treatment. here, we report a customized recombin ...200818827193
viral and bacterial serology of six free-ranging bearded seals erignathus barbatus.serum or heparinized plasma samples were obtained from 3 male (2 adult and 1 weaned calf) and 3 adult female free-ranging bearded seals erignathus barbatus in may of 1994, 1995, or 1996. blood samples were obtained from animals taken in subsistence hunts near st. lawrence island, alaska and screened for antibodies to a suite of bacteria and viruses potentially pathogenic for pinnipeds and/or humans. no samples had detectable antibodies to brucella spp., phocine distemper virus, influenza a virus ...200818828565
[optimization of prokaryotic expression conditions of leptospira interrogans trigeminy genus-specific protein antigen based on surface response analysis].lipoproteins lipl32 and lipl21 and transmembrane protein ompl1 have been confirmed as the superficial genus-specific antigens of leptospira interrogans, which can be used as antigens for developing a universal genetic engineering vaccine.200818837366
[application of multilocus variable-number tandem-repeat analysis for gene typing and epidemiology of leptospira interrogans]. 200818844004
hprk regulates succinate-mediated catabolite repression in the gram-negative symbiont sinorhizobium meliloti.the hprk kinase/phosphatase is a common component of the phosphotransferase system (pts) of gram-positive bacteria and regulates catabolite repression through phosphorylation/dephosphorylation of its substrate, the pts protein hpr, at a conserved serine residue. phosphorylation of hpr by hprk also affects additional phosphorylation of hpr by the pts enzyme ei at a conserved histidine residue. sinorhizobium meliloti can live as symbionts inside legume root nodules or as free-living organisms and ...200918931135
hprk regulates succinate-mediated catabolite repression in the gram-negative symbiont sinorhizobium meliloti.the hprk kinase/phosphatase is a common component of the phosphotransferase system (pts) of gram-positive bacteria and regulates catabolite repression through phosphorylation/dephosphorylation of its substrate, the pts protein hpr, at a conserved serine residue. phosphorylation of hpr by hprk also affects additional phosphorylation of hpr by the pts enzyme ei at a conserved histidine residue. sinorhizobium meliloti can live as symbionts inside legume root nodules or as free-living organisms and ...200918931135
directed evolution of methanococcus jannaschii citramalate synthase for biosynthesis of 1-propanol and 1-butanol by escherichia coli.biofuels synthesized from renewable resources are of increasing interest because of global energy and environmental problems. we have previously demonstrated production of higher alcohols from escherichia coli using a 2-keto acid-based pathway. here, we took advantage of the growth phenotype associated with 2-keto acid deficiency to construct a hyperproducer of 1-propanol and 1-butanol by evolving citramalate synthase (cima) from methanococcus jannaschii. this new pathway, which directly convert ...200818952866
protection of guinea pigs against leptospira interrogans serovar lai by lipl21 dna vaccine.in this study, the full lipl21 gene fragment encoding outer membrane protein lipl21 was cloned from l. interrogans serovar lai and inserted into eukaryotic expression vector pcdna3.1(+). the guinea pigs were immunized with pcdna3.1(+)-lipl21, pcdna3.1(+) or pbs. six weeks after the second immunization, the splenocytes were isolated to detect their proliferative ability by lymphocyte transformation experiments. in addition, microscopic agglutination test was used for quantitative detection of spe ...200818954563
leptospirosis in wild and domestic carnivores in natural areas in andalusia, spain.leptospirosis is a zoonosis that affects humans, domestic animals, and wildlife. carnivores are at the top of the feeding chain, thus being exposed to pathogens through their preys. from june 2004 to april 2007, we analyzed for evidences of contact with 14 serovars of leptospira interrogans sensu lato serum (analyzed by indirect microscopic agglutination test) and urine or kidney samples (analyzed by microscopic observation, immunostaining and culture) collected from 201 wild and domestic carniv ...200918973450
intermediate filament-like proteins in bacteria and a cytoskeletal function in streptomyces.actin and tubulin cytoskeletons are conserved and widespread in bacteria. a strikingly intermediate filament (if)-like cytoskeleton, composed of crescentin, is also present in caulobacter crescentus and determines its specific cell shape. however, the broader significance of this finding remained obscure, because crescentin appeared to be unique to caulobacter. here we demonstrate that if-like function is probably a more widespread phenomenon in bacteria. first, we show that 21 genomes of 26 phy ...200818976278
analyses of vaccination protocols for leptospira interrogans serovar autumnalis in hamsters.leptospirosis, caused by leptospira spp., is a zoonotic disease found worldwide. killed whole cell leptospiral vaccines have been used as effective vaccines to elicit specific antibodies for protection. however, the involvement of cytokine responses after vaccination is not well characterized. hamsters were immunized with killed l. interrogans serovar autumnalis before challenge to study cytokine mrna expression levels (interferon [ifn]-gamma, tumor necrosis factor [tnf]-alpha, interleukin [il]- ...200818981522
vntr analysis reveals unexpected genetic diversity within mycoplasma agalactiae, the main causative agent of contagious agalactia.mycoplasma agalactiae is the main cause of contagious agalactia, a serious disease of sheep and goats, which has major clinical and economic impacts. previous studies of m. agalactiae have shown it to be unusually homogeneous and there are currently no available epidemiological techniques which enable a high degree of strain differentiation.200818992155
expression, crystallization and preliminary x-ray crystallographic analysis of peptide deformylase from xanthomonas oryzae pv. oryzae.peptide deformylase (pdf) catalyzes the removal of the n-formyl group from the n-terminus of newly synthesized polypeptides; this process is crucial for cell survival. as it is an antibacterial drug target against xanthomonas oryzae pv. oryzae (xoo), pdf from xoo was cloned, expressed, purified and crystallized. native pdf crystals diffracted to 2.7 a resolution and belonged to the hexagonal space group p6(1)22, with unit-cell parameters a = b = 59.0, c = 266.3 a. one monomer is present in the a ...200818997334
serodiagnosis of severe leptospirosis: evaluation of elisa based on the recombinant ompl1 or lipl41 antigens of leptospira interrogans serovar autumnalis.elisa based on the recombinant ompl1 and lipl41 antigens of leptospira interrogans serovar autumnalis strain n2 have been developed, for the serodiagnosis of the severe pulmonary form of leptospirosis on the endemic andaman islands. the recombinant ompl1 and lipl41 were produced using escherichia coli expression systems and then purified before each was evaluated in an igm-elisa. the sera tested came from 224 patients who had the severe form of leptospirosis and pulmonary pneumonitis as major sy ...200819000387
monitoring of leptospirosis seroprevalence in a colony of captive collared peccaries (tayassu tajacu) from the peruvian amazon.leptospirosis, an endemic zoonoses, is maintained in the environment by several wildlife species in the peruvian amazon. in order to evaluate the possible role of collared peccaries (cp) in the maintenance this disease, two serological surveys of leptospirosis were performed and zootechnical parameters were monitored in a captive cp colony in an interval of 27 months. total seroprevalence changed from 100% (n=27) to 86.4% (n=22), with reactions to a diversity of serogroups of zoonotic importance ...200919000627
phylogenetic construction of 17 bacterial phyla by new method and carefully selected orthologs.here, we constructed a phylogenetic tree of 17 bacterial phyla covering eubacteria and archaea by using a new method and 102 carefully selected orthologs from their genomes. one of the serious disturbing factors in phylogeny construction is the existence of out-paralogs that cannot easily be found out and discarded. in our method, out-paralogs are detected and removed by constructing a phylogenetic tree of the genes in question and examining the clustered genes in the tree. we also developed a m ...200819000750
phylogenetic construction of 17 bacterial phyla by new method and carefully selected orthologs.here, we constructed a phylogenetic tree of 17 bacterial phyla covering eubacteria and archaea by using a new method and 102 carefully selected orthologs from their genomes. one of the serious disturbing factors in phylogeny construction is the existence of out-paralogs that cannot easily be found out and discarded. in our method, out-paralogs are detected and removed by constructing a phylogenetic tree of the genes in question and examining the clustered genes in the tree. we also developed a m ...200819000750
diagnosis of leptospirosis by recombinant antigen based single serum dilution elisa.leptospirosis, a zoonosis with a worldwide distribution is an acute febrile illness caused by spirochaetes of the pathogenic leptospira interrogans. microscopic agglutination test (mat), the reference method for diagnosis was successively done to evaluate the modified elisa which was developed with the recombinant lipl32 antigen for the detection of anti-leptospiral antibodies in human serum samples.200819001681
human leptospira interrogans serogroup icterohaemorrhagiae infection (weil's disease) acquired from pet rats. 200819011247
haem acquisition is facilitated by a novel receptor hma and required by uropathogenic escherichia coli for kidney infection.iron acquisition, mediated by specific outer membrane receptors, is critical for colonization of the urinary tract by uropathogenic escherichia coli (upec). the role of specific iron sources in vivo, however, remains largely unknown. in this study, we identified a 79 kda haem receptor, haemacquisition protein hma, and established that it functions independently of chua to mediate haemin uptake by upec strain cft073. we demonstrated that expression of hma promotes tonb-dependent haemin utilizatio ...200919019144
haem acquisition is facilitated by a novel receptor hma and required by uropathogenic escherichia coli for kidney infection.iron acquisition, mediated by specific outer membrane receptors, is critical for colonization of the urinary tract by uropathogenic escherichia coli (upec). the role of specific iron sources in vivo, however, remains largely unknown. in this study, we identified a 79 kda haem receptor, haemacquisition protein hma, and established that it functions independently of chua to mediate haemin uptake by upec strain cft073. we demonstrated that expression of hma promotes tonb-dependent haemin utilizatio ...200919019144
leptospira immunoglobulin-like protein a variable region (ligavar) incorporated in liposomes and plga microspheres produces a robust immune response correlating to protective immunity.subunit vaccines are attractive as an intervention strategy against leptospirosis, an important zoonotic disease afflicting both humans and livestock. however, the success of subunit vaccines has been hampered by weak or short-term immunity and unavailability of nontoxic, potent adjuvants. in the present study, the variable region of recombinant leptospira immunoglobulin like protein a (ligavar) incorporated into conventional liposomes and plga microspheres produced robust immune responses that ...200919022317
transcription and genetic analyses of a putative n-acetylmuramyl-l-alanine amidase in borrelia burgdorferi.in this study, a putative n-acetylmuramyl-l-alanine amidase gene (bb0666) was identified in the genome of the lyme disease spirochete borrelia burgdorferi. this protein shares c. 30% identity with its counterparts from other bacteria. reverse transcriptase-pcr analysis showed that bb0666 along with two other genes (bb0665 and bb0667) are cotranscribed with the motility and chemotaxis genes. this newly identified operon is termed as pami. sequence and primer extension analyses showed that pami wa ...200919025570
transcription and genetic analyses of a putative n-acetylmuramyl-l-alanine amidase in borrelia burgdorferi.in this study, a putative n-acetylmuramyl-l-alanine amidase gene (bb0666) was identified in the genome of the lyme disease spirochete borrelia burgdorferi. this protein shares c. 30% identity with its counterparts from other bacteria. reverse transcriptase-pcr analysis showed that bb0666 along with two other genes (bb0665 and bb0667) are cotranscribed with the motility and chemotaxis genes. this newly identified operon is termed as pami. sequence and primer extension analyses showed that pami wa ...200919025570
genetic diversity of the leptospiral immunoglobulin-like (lig) genes in pathogenic leptospira spp.recent serologic, immunoprotection, and pathogenesis studies identified the lig proteins as key virulence determinants in interactions of leptospiral pathogens with the mammalian host. we examined the sequence variation and recombination patterns of liga, ligb, and ligc among 10 pathogenic strains from five leptospira species. all strains were found to have intact ligb genes and genetic drift accounting for most of the ligb genetic diversity observed. the liga gene was found exclusively in l. in ...200919028604
leptospira interrogans induces apoptosis in macrophages via caspase-8- and caspase-3-dependent pathways.apoptosis of host cells plays an important role in modulating the pathogenesis of many infectious diseases. it has been reported that leptospira interrogans, the causal agent of leptospirosis, induces apoptosis in macrophages and hepatocytes. however, the molecular mechanisms responsible for host cell death remained largely unknown. here we demonstrate that l. interrogans induced apoptosis in a macrophage-like cell line, j774a.1, and primary murine macrophages in a time- and dose-dependent manne ...200919029301
genome-wide transposon mutagenesis in pathogenic leptospira species.leptospira interrogans is the most common cause of leptospirosis in humans and animals. genetic analysis of l. interrogans has been severely hindered by a lack of tools for genetic manipulation. recently we developed the mariner-based transposon himar1 to generate the first defined mutants in l. interrogans. in this study, a total of 929 independent transposon mutants were obtained and the location of insertion determined. of these mutants, 721 were located in the protein coding regions of 551 d ...200919047402
predictors of lethality in severe leptospirosis in urban brazil.to ascertain prognostic factors associated with fatal outcomes in severe leptospirosis, a retrospective case-control study was done using population-based surveillance data. centralized death certificate reporting of leptospirosis mortality was combined with details of patients' hospitalizations, which were obtained from hospitals representing all sectors of são paulo city. among identified leptospirosis cases, 89 lethal cases and 281 survivor cases were analyzed. predictors of death included ag ...200819052303
case report: severe, symptomatic hypomagnesemia in acute leptospirosis.we report a case of severe hypomagnesemia in non-oliguric acute renal failure caused by leptospirosis that required large doses of magnesium replacement during the acute phase of disease. biochemical studies confirmed kidney-related magnesium wasting and the mechanisms of this defect are discussed. magnesium imbalance with its attendant clinical complications occurs in leptospirosis and should be monitored and treated aggressively in cases of leptospirosis-induced non-oliguric acute kidney injur ...200819052304
overcoming function annotation errors in the gram-positive pathogen streptococcus suis by a proteomics-driven approach.annotation of protein-coding genes is a key step in sequencing projects. protein functions are mainly assigned on the basis of the amino acid sequence alone by searching of homologous proteins. however, fully automated annotation processes often lead to wrong prediction of protein functions, and therefore time-intensive manual curation is often essential. here we describe a fast and reliable way to correct function annotation in sequencing projects, focusing on surface proteomes. we use a proteo ...200819061494
immunogenicity and protective efficacy of recombinant leptospira immunoglobulin-like protein b (rligb) in a hamster challenge model.leptospiral immunoglobulin-like protein (ligb) was truncated into conserved (ligbcon) and variable (varb1, varb2) fragments and expressed as gst/his-tag fusion proteins. four-week-old hamsters were immunized with equal amounts of each fragment individually or combined in alum adjuvant at days 0 and 21 and subsequently challenged three weeks after the booster with 2.5 ld(50) live virulent leptospira interrogans serovar pomona. our results demonstrate that immunization with ligb produced strong hu ...200919070678
[advance in research of pathogenic mechanism and novel genetic engineering vaccines of leptospira interrogans and bacterial drug resistance]. 200819084949
[upregulation of fasl/fas expression and fasl/fas-associated apoptosis in j774a.1 cells induced by leptospira interrogans].to determine the involvement of fasl/fas pathway in apoptosis of j774a.1 cells induced by leptospira interrogans.200819084951
[j774a.1 cell apoptosis induced by leptospira interrogans and effects of caspase-3, -6 activation on apoptosis].to investigate the apoptosis of j774a.1 cells induced by leptospira interrogans and the effect of caspase-3, -6 activation on the apoptosis.200819084952
[sequences and expression pattern of mce gene in leptospira interrogans of different serogroups].to determine the frequency of mce gene in leptospira interrogans, and to investigate the gene transcription levels of l. interrogans before and after infecting cells.200819084953
[association of flir gene in leptospira interrogans with adhesion and pathogenicity to host cells].to investigate the pathogenicity of leptospira interrogans flir gene to j774a.1 cells.200819084954
[adhering effect of leptospira interrongan to major extracellular matrix molecules].to determine the adhering ability of leptospira interrogans to extracellular matrix molecules (ecm) of host cells and its diversity.200819084955
[prediction and immunologic identification of antigenic epitopes in genus-specific outer membrane protein lipl41 of leptospira interrogans].to predict and screen the efficient antigenic epitopes in genus-specific envelope protein lipl41 of leptospira interrogans and to determine the immunoreactive diversity of lipl41s from different genotypes.200819084956
[establishment and application of elisas based on rlipl32/1-lipl21-ompl1/2 fusion antigen of leptospira interrogans].to establish elisas based on rlipl32/1-lipl21-ompl1/2 fusion antigen of leptospira interrogans for detecting specific igg and igm in serum of patients with leptospirosis.200819084957
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