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leptospirosis outbreak in sri lanka in 2008: lessons for assessing the global burden of disease.global leptospirosis disease burden estimates are hampered by the lack of scientifically sound data from countries with probable high endemicity and limited diagnostic capacities. we describe the seroepidemiologic and clinical characteristics of the leptospirosis outbreak in 2008 in sri lanka. definitive/presumptive case definitions proposed by the world health organization leptospirosis epidemiology reference group were used for case confirmation. of the 404 possible cases, 155 were confirmed t ...201121896807
detection of leptospira in urine using anti-leptospira-coated gold nanoparticles.serological assays for antibody detection have been widely used for leptospirosis diagnosis. however, antibody is usually undetectable during the first week after infection. detection of leptospira dna can be done by pcr but this technique requires special equipments and the cost is still relatively high. here we demonstrate that gold nanoparticles can be used to facilitate leptospira detection. gold nanoparticles were coated with rabbit antibody specific to leptospira interrogans serovar bratis ...201120015548
an outbreak of severe leptospirosis in capuchin (cebus) monkeys.naturally acquired acute leptospirosis in monkeys is uncommon. this study reports an outbreak of severe leptospirosis among 52 capuchin (cebus) monkeys that had been rescued from homes and housed in a wildlife rehabilitation center in colombia in 2007. case confirmation consisted of leptospira isolation followed by a polymerase chain reaction targeting the lipl32 gene. the attack and mortality rates were 71% and 27%, respectively. sixteen cases were confirmed. necropsy revealed diffuse jaundice ...201120554228
plasmodium immunomics.the plasmodium parasite, the causative agent of malaria, is an excellent model for immunomic-based approaches to vaccine development. the plasmodium parasite has a complex life cycle with multiple stages and stage-specific expression of ∼5300 putative proteins. no malaria vaccine has yet been licensed. many believe that an effective vaccine will need to target several antigens and multiple stages, and will require the generation of both antibody and cellular immune responses. vaccine efforts to ...201120816843
plasmodium immunomics.the plasmodium parasite, the causative agent of malaria, is an excellent model for immunomic-based approaches to vaccine development. the plasmodium parasite has a complex life cycle with multiple stages and stage-specific expression of ∼5300 putative proteins. no malaria vaccine has yet been licensed. many believe that an effective vaccine will need to target several antigens and multiple stages, and will require the generation of both antibody and cellular immune responses. vaccine efforts to ...201120816843
increased immunogenicity to lipl32 of leptospira interrogans when expressed as a fusion protein with the cholera toxin b subunit.leptospirosis is one of the most widespread zoonosis in the world. the development of a recombinant leptospira vaccine remains a challenge. in this study, we cloned the leptospira interrogans open reading frame (orf) coding the external membrane protein lipl32, an immunodominant antigen found in all pathogenic leptospira, downstream of the highly immunogenic cholera toxin b subunit (ctb) orf. expression and assembly of the ctb-lipl32 fusion protein into oligomeric structures of pentameric size w ...201120721666
evaluation of the use of selective pcr amplification of lps biosynthesis genes for molecular typing of leptospira at the serovar level.leptospirosis is an important epidemic zoonosis worldwide. currently, there are more than 250 leptospira pathogenic serovars known that can potentially infect humans. conventional classification of leptospires with the serovar as the basic taxon, based on serological recognition of lipopolysaccharide (lps) composition does not correlate well with species determination, based on general genomic features. here, we investigate the selective amplification of polymorphic regions from the lps biosynth ...201120721667
structures of domains i and iv from ybbr are representative of a widely distributed protein family.ybbr domains are widespread throughout eubacteria and are expressed as monomeric units, linked in tandem repeats or cotranslated with other domains. although the precise role of these domains remains undefined, the location of the multiple ybbr domain-encoding ybbr gene in the bacillus subtilis glmm operon and its previous identification as a substrate for a surfactin-type phosphopantetheinyl transferase suggests a role in cell growth, division, and virulence. to further characterize the ybbr do ...201121154411
structures of domains i and iv from ybbr are representative of a widely distributed protein family.ybbr domains are widespread throughout eubacteria and are expressed as monomeric units, linked in tandem repeats or cotranslated with other domains. although the precise role of these domains remains undefined, the location of the multiple ybbr domain-encoding ybbr gene in the bacillus subtilis glmm operon and its previous identification as a substrate for a surfactin-type phosphopantetheinyl transferase suggests a role in cell growth, division, and virulence. to further characterize the ybbr do ...201121154411
putting structure into context: fitting of atomic models into electron microscopic and electron tomographic reconstructions.a complete understanding of complex dynamic cellular processes such as cell migration or cell adhesion requires the integration of atomic level structural information into the larger cellular context. while direct atomic-level information at the cellular level remains inaccessible, electron microscopy, electron tomography and their associated computational image processing approaches have now matured to a point where sub-cellular structures can be imaged in three dimensions at the nanometer scal ...201122152946
putting structure into context: fitting of atomic models into electron microscopic and electron tomographic reconstructions.a complete understanding of complex dynamic cellular processes such as cell migration or cell adhesion requires the integration of atomic level structural information into the larger cellular context. while direct atomic-level information at the cellular level remains inaccessible, electron microscopy, electron tomography and their associated computational image processing approaches have now matured to a point where sub-cellular structures can be imaged in three dimensions at the nanometer scal ...201122152946
investment in rapid growth shapes the evolutionary rates of essential proteins.proteins evolve at very different rates and, most notably, at rates inversely proportional to the level at which they are produced. the relative frequency of highly expressed proteins in the proteome, and thus their impact on the cell budget, increases steeply with growth rate. the maximal growth rate is a key life-history trait reflecting trade-offs between rapid growth and other fitness components. we show that the maximal growth rate is weakly affected by genetic drift. the negative correlati ...201122135464
bridging the gap between validation and implementation of non-animal veterinary vaccine potency testing methods.in recent years, technologically advanced high-throughput techniques have been developed that replace, reduce or refine animal use in vaccine quality control tests. following validation, these tests are slowly being accepted for use by international regulatory authorities. because regulatory acceptance itself has not guaranteed that approved humane methods are adopted by manufacturers, various organizations have sought to foster the preferential use of validated non-animal methods by interfacing ...201126486625
proteogenomic analysis of bacteria and archaea: a 46 organism case study.experimental evidence is increasingly being used to reassess the quality and accuracy of genome annotation. proteomics data used for this purpose, called proteogenomics, can alleviate many of the problematic areas of genome annotation, e.g. short protein validation and start site assignment. we performed a proteogenomic analysis of 46 genomes spanning eight bacterial and archaeal phyla across the tree of life. these diverse datasets facilitated the development of a robust approach for proteogeno ...201122114679
generic comparison of protein inference engines.protein identifications, instead of peptide-spectrum matches, constitute the biologically relevant result of shotgun proteomics studies. how to appropriately infer and report protein identifications has triggered a still ongoing debate. this debate has so far suffered from the lack of appropriate performance measures that allow us to objectively assess protein inference approaches. this study describes an intuitive, generic and yet formal performance measure and demonstrates how it enables exper ...201122057310
generic comparison of protein inference engines.protein identifications, instead of peptide-spectrum matches, constitute the biologically relevant result of shotgun proteomics studies. how to appropriately infer and report protein identifications has triggered a still ongoing debate. this debate has so far suffered from the lack of appropriate performance measures that allow us to objectively assess protein inference approaches. this study describes an intuitive, generic and yet formal performance measure and demonstrates how it enables exper ...201122057310
toll-like receptors and myocardial inflammation.toll-like receptors (tlrs) are a member of the innate immune system. tlrs detect invading pathogens through the pathogen-associated molecular patterns (pamps) recognition and play an essential role in the host defense. tlrs can also sense a large number of endogenous molecules with the damage-associated molecular patterns (damps) that are produced under various injurious conditions. animal studies of the last decade have demonstrated that tlr signaling contributes to the pathogenesis of the crit ...201121977329
leptospirosis as frequent cause of acute febrile illness in southern sri lanka.to determine the proportion of fevers caused by leptospirosis, we obtained serum specimens and epidemiologic and clinical data from patients in galle, sri lanka, march-october 2007. immunoglobulin m elisa was performed on paired serum specimens to diagnose acute (seroconversion or 4-fold titer rise) or past (titer without rise) leptospirosis and seroprevalence (acute). we compared (individually) the diagnostic yield of acute-phase specimens and clinical impression with paired specimens for acute ...201121888794
leptospirosis among hospitalized febrile patients in northern tanzania.we enrolled consecutive febrile admissions to two hospitals in moshi, tanzania. confirmed leptospirosis was defined as a ≥ 4-fold increase in microscopic agglutination test (mat) titer; probable leptospirosis as reciprocal mat titer ≥ 800; and exposure to pathogenic leptospires as titer ≥ 100. among 870 patients enrolled in the study, 453 (52.1%) had paired sera available, and 40 (8.8%) of these met the definition for confirmed leptospirosis. of 832 patients with ≥ 1 serum sample available, 30 ( ...201121813847
similar structures but different roles - an updated perspective on tlr structures.toll-like receptors (tlrs) are pattern recognition receptors that recognize conserved structures in pathogens, trigger innate immune responses, and prime antigen-specific adaptive immunity. elucidation of crystal structures of tlrs interacting with their ligands such as tlr1-2 with triacylated lipopeptide, tlr2-6 with diacylated lipopeptide, tlr4-md-2 with lps, and tlr3 with double-stranded rna (dsrna) have enabled an understanding of the initiation of tlr signaling. agonistic ligands such as lp ...201121845181
production of reactive oxygen (h2o2) and nitrogen (no) intermediates and tnf-α in mice genetically selected for high (h) and low (l) antibody response and experimentally infected with leptospira serovar pomona.the aim of the present study was to evaluate the activity of macrophages, and the production of tnf-α and antibodies against experimental infection by leptospira serovar pomona in mice genetically selected for high (h) or low (l) humoral immune response. to evaluate macrophagic activity, peritoneal and splenic lavages were performed for determination of oxygen (h2o2) and nitrogen (no) intermediates. the production of the tumor necrosis factor (tnf-α) was investigated through bioassays in serum a ...201124031688
outpatient follow-up of patients hospitalized for acute leptospirosis.the outcome of leptospirosis after the resolution of acute disease, either spontaneously or after treatment, is not well described. the aim of this study was to assess the possible sequelae of acute leptospirosis after hospital discharge.201121616696
trapping conformational states along ligand-binding dynamics of peptide deformylase: the impact of induced fit on enzyme catalysis.for several decades, molecular recognition has been considered one of the most fundamental processes in biochemistry. for enzymes, substrate binding is often coupled to conformational changes that alter the local environment of the active site to align the reactive groups for efficient catalysis and to reach the transition state. adaptive substrate recognition is a well-known concept; however, it has been poorly characterized at a structural level because of its dynamic nature. here, we provide ...201121629676
sporadic urban leptospirosis.severe leptospirosis (weil syndrome) was diagnosed in an otherwise healthy environmental worker in baltimore alleys in late november 2010. he developed multiple organ failure but responded to antibiotic therapy and experienced a full recovery within 4 weeks. his diagnosis was confirmed by a rise in indirect hemagglutinin titer (acute 0, convalescent 400). the subject had close contact with baltimore alley rats; a similar epidemiologic exposure and location reported in an outbreak 15 years ago.201123882321
chemical analysis of single cells. 201121500835
directed networks reveal genomic barriers and dna repair bypasses to lateral gene transfer among prokaryotes.lateral gene transfer (lgt) plays a major role in prokaryote evolution with only a few genes that are resistant to it; yet the nature and magnitude of barriers to lateral transfer are still debated. here, we implement directed networks to investigate donor-recipient events of recent lateral gene transfer among 657 sequenced prokaryote genomes. for 2,129,548 genes investigated, we detected 446,854 recent lateral gene transfer events through nucleotide pattern analysis. among these, donor-recipien ...201121270172
ataqs: a computational software tool for high throughput transition optimization and validation for selected reaction monitoring mass spectrometry.since its inception, proteomics has essentially operated in a discovery mode with the goal of identifying and quantifying the maximal number of proteins in a sample. increasingly, proteomic measurements are also supporting hypothesis-driven studies, in which a predetermined set of proteins is consistently detected and quantified in multiple samples. selected reaction monitoring (srm) is a targeted mass spectrometric technique that supports the detection and quantification of specific proteins in ...201121414234
[application of multiple-locus variable number tandem repeat analysis (mlva) on molecular typing of leptospira interrogans]. 201022997605
unifying themes in microbial associations with animal and plant hosts described using the gene ontology.microbes form intimate relationships with hosts (symbioses) that range from mutualism to parasitism. common microbial mechanisms involved in a successful host association include adhesion, entry of the microbe or its effector proteins into the host cell, mitigation of host defenses, and nutrient acquisition. genes associated with these microbial mechanisms are known for a broad range of symbioses, revealing both divergent and convergent strategies. effective comparisons among these symbioses, ho ...201021119014
exploring the spatial and temporal organization of a cell's proteome.to increase our current understanding of cellular processes, such as cell signaling and division, knowledge is needed about the spatial and temporal organization of the proteome at different organizational levels. these levels cover a wide range of length and time scales: from the atomic structures of macromolecules for inferring their molecular function, to the quantitative description of their abundance, and spatial distribution in the cell. emerging new experimental technologies are greatly i ...201021094684
exploring the spatial and temporal organization of a cell's proteome.to increase our current understanding of cellular processes, such as cell signaling and division, knowledge is needed about the spatial and temporal organization of the proteome at different organizational levels. these levels cover a wide range of length and time scales: from the atomic structures of macromolecules for inferring their molecular function, to the quantitative description of their abundance, and spatial distribution in the cell. emerging new experimental technologies are greatly i ...201021094684
leptospirosis presenting in a woman with fulminant hepatic failure from wilson's disease: a case report.we report an unusual case of wilson's disease that was revealed by presentation of leptospirosis. the prompt detection of this potentially life-threatening disease highlights the importance of careful investigation. to the best of our knowledge, this is the first reported case of leptospirosis involving the development of fulminant liver failure due to wilson's disease.201020698945
differences in clinical manifestations of imported versus autochthonous leptospirosis in austria and germany.leptospirosis, a zoonosis occurring worldwide, has a broad spectrum of clinical manifestations. recently, various countries observed an increase of severe anicteric cases. in austria and germany, growing numbers of imported cases are notified in addition to autochthonous infections. the aim of this study was to assess whether imported and autochthonous cases differ in clinical manifestations and outcome. we retrospectively analyzed 24 imported and 35 autochthonous cases treated in six infectious ...201020682876
nuclear receptors and inflammation control: molecular mechanisms and pathophysiological relevance.tissue inflammation is a tightly regulated process that normally serves to recruit the immune system to sites of infection and injury and to facilitate tissue repair processes. when an inflammatory state is excessive or prolonged, local and systemic damage to host tissues can result in loss of normal physiological functions. here, we briefly review recent studies that advance our understanding of signaling pathways involved in initiation of inflammatory responses at the level of transcription an ...201020631355
intergenic transposable elements are not randomly distributed in bacteria.insertion sequences (iss) are mobile genetic elements in bacterial genomes. in general, intergenic is elements are probably less deleterious for their hosts than intragenic iss, simply because they have a lower likelihood of disrupting native genes. however, since promoters, shine-dalgarno sequences, and transcription factor binding sites are intergenic and upstream of genes, i hypothesized that not all neighboring gene orientations (ngos) are selectively equivalent for is insertion. to test thi ...201020697140
toll-like receptor agonists: are they good adjuvants?therapeutic immunization leading to cancer regression remains a significant challenge. successful immunization requires activation of adaptive immunity, including tumor specific cd4 t cells and cd8 t cells. generally, the activation of t cells is compromised in patients with cancer because of immune suppression, loss of tumor antigen expression, and dysfunction of antigen-presenting cells. antigen-presenting cells such as dendritic cells (dcs) are key for the induction of adaptive antitumor immu ...201020693851
save the tree of life or get lost in the woods.the wealth of prokaryotic genomic data available has revealed that the histories of many genes are inconsistent, leading some to question the value of the tree of life hypothesis. it has been argued that a tree-like representation requires suppressing too much information, and that a more pluralistic approach is necessary for understanding prokaryotic evolution. we argue that trees may still be a useful representation for evolutionary histories in light of new data.201020594329
host-microbe interactions in the developing zebrafish.the amenability of the zebrafish to in vivo imaging and genetic analysis has fueled expanded use of this vertebrate model to investigate the molecular and cellular foundations of host-microbe relationships. study of microbial encounters in zebrafish hosts has concentrated on developing embryonic and larval stages, when the advantages of the zebrafish model are maximized. a comprehensive understanding of these host-microbe interactions requires appreciation of the developmental context into which ...201020153622
a persistent and diverse airway microbiota present during chronic obstructive pulmonary disease exacerbations.acute exacerbations of chronic obstructive pulmonary disease (copd) are a major source of morbidity and contribute significantly to healthcare costs. although bacterial infections are implicated in nearly 50% of exacerbations, only a handful of pathogens have been consistently identified in copd airways, primarily by culture-based methods, and the bacterial microbiota in acute exacerbations remains largely uncharacterized. the aim of this study was to comprehensively profile airway bacterial com ...201020141328
the path to next generation biofuels: successes and challenges in the era of synthetic biology.volatility of oil prices along with major concerns about climate change, oil supply security and depleting reserves have sparked renewed interest in the production of fuels from renewable resources. recent advances in synthetic biology provide new tools for metabolic engineers to direct their strategies and construct optimal biocatalysts for the sustainable production of biofuels. metabolic engineering and synthetic biology efforts entailing the engineering of native and de novo pathways for con ...201020089184
leptospirosis diagnosed by molecular dna detection on skin biopsy.leptospirosis is one of the most common anthropozoonoses in the world. humans are accidental hosts who get infected through damaged skin or conjunctiva from environmental sources such as soil and water contaminated by urine or tissues from infected animals. we report the case of a young man for whom the diagnosis was obtained by polymerase chain reaction (pcr) detection from a skin biopsy.201022242069
tlr cross-talk mechanism of hemorrhagic shock-primed pulmonary neutrophil infiltration.hemorrhage resulted from severe trauma renders patients susceptible to the development of acute lung injury (ali). the accumulation of polymorphonuclear neutrophils (pmn) in the lung is a critical event in the development of ali. pmn migration is a result of a cascade of cellular events, in which pmn, endothelial cells (ec), and macrophages (mϕ) act in concert. recent studies explored interrelated novel findings indicating that toll-like receptors (tlrs) cross-talk mechanisms occurring in pmn, e ...201020072711
early identification of leptospirosis-associated pulmonary hemorrhage syndrome by use of a validated prediction model.to identify prediction factors for the development of leptospirosis-associated pulmonary hemorrhage syndrome (lphs).201020026189
early identification of leptospirosis-associated pulmonary hemorrhage syndrome by use of a validated prediction model.to identify prediction factors for the development of leptospirosis-associated pulmonary hemorrhage syndrome (lphs).201020026189
leptospira interrogans associated with hydrallantois in 2 pluriparous thoroughbred mares. 201021155889
2010 acvim small animal consensus statement on leptospirosis: diagnosis, epidemiology, treatment, and prevention.this report offers a consensus opinion on the diagnosis, epidemiology, treatment, and prevention of leptospirosis in dogs, an important zoonosis. clinical signs of leptospirosis in dogs relate to development of renal disease, hepatic disease, uveitis, and pulmonary hemorrhage. disease may follow periods of high rainfall, and can occur in dogs roaming in proximity to water sources, farm animals, or wildlife, or dogs residing in suburban environments. diagnosis is based on acute and convalescent p ...201021155890
stable expression of leptospira interrogans antigens in auxotrophic mycobacterium bovis bcg.mycobacterium bovis bcg has been proposed as an effective live vector for multivalent vaccines. the development of mycobacterial genetic systems to express foreign antigens and the adjuvanticity of bcg are the basis for the potential use of this attenuated mycobacterium as a recombinant vaccine vector. stable plasmid vectors without antibiotic resistance markers are needed for heterologous antigen expression in bcg. our group recently described the construction of a bcg expression system using a ...201021157628
methylthioadenosine/s-adenosylhomocysteine nucleosidase, a critical enzyme for bacterial metabolism.the importance of methylthioadenosine/s-adenosylhomocysteine (mta/sah) nucleosidase in bacteria has started to be appreciated only in the past decade. a comprehensive analysis of its various roles here demonstrates that it is an integral component of the activated methyl cycle, which recycles adenine and methionine through s-adenosylmethionine (sam)-mediated methylation reactions, and also produces the universal quorum-sensing signal, autoinducer-2 (ai-2). sam is also essential for synthesis of ...201021166890
methylthioadenosine/s-adenosylhomocysteine nucleosidase, a critical enzyme for bacterial metabolism.the importance of methylthioadenosine/s-adenosylhomocysteine (mta/sah) nucleosidase in bacteria has started to be appreciated only in the past decade. a comprehensive analysis of its various roles here demonstrates that it is an integral component of the activated methyl cycle, which recycles adenine and methionine through s-adenosylmethionine (sam)-mediated methylation reactions, and also produces the universal quorum-sensing signal, autoinducer-2 (ai-2). sam is also essential for synthesis of ...201021166890
responses of human endothelial cells to pathogenic and non-pathogenic leptospira species.leptospirosis is a widespread zoonotic infection that primarily affects residents of tropical regions, but causes infections in animals and humans in temperate regions as well. the agents of leptospirosis comprise several members of the genus leptospira, which also includes non-pathogenic, saprophytic species. leptospirosis can vary in severity from a mild, non-specific illness to severe disease that includes multi-organ failure and widespread endothelial damage and hemorrhage. to begin to inves ...201021179504
leptospirosis: a toll road from b lymphocytes.leptospirosis is a widespread zoonosis caused by leptospira interrogans, a pathogen transmitted by asymptomatic infected rodents. leptospiral lipoproteins and lipopolysaccharide (lps) have been shown to stimulate murine cells via toll-like receptors (tlrs) 2 and 4. host defense mechanisms remain obscure, although tlr4 has been associated with clearing leptospira. in a recent study, we showed that in response to leptospira infection, double (tlr2 and tlr4) knock-out (dko) mice unexpectedly develo ...201021199604
self-mating in the definitive host potentiates clonal outbreaks of the apicomplexan parasites sarcocystis neurona and toxoplasma gondii.tissue-encysting coccidia, including toxoplasma gondii and sarcocystis neurona, are heterogamous parasites with sexual and asexual life stages in definitive and intermediate hosts, respectively. during its sexual life stage, t. gondii reproduces either by genetic out-crossing or via clonal amplification of a single strain through self-mating. out-crossing has been experimentally verified as a potent mechanism capable of producing offspring possessing a range of adaptive and virulence potentials. ...201021203443
big domains are novel ca²+-binding modules: evidences from big domains of leptospira immunoglobulin-like (lig) proteins.many bacterial surface exposed proteins mediate the host-pathogen interaction more effectively in the presence of ca²+. leptospiral immunoglobulin-like (lig) proteins, liga and ligb, are surface exposed proteins containing bacterial immunoglobulin like (big) domains. the function of proteins which contain big fold is not known. based on the possible similarities of immunoglobulin and βγ-crystallin folds, we here explore the important question whether ca²+ binds to a big domains, which would prov ...201021206924
overoxidation of 2-cys peroxiredoxin in prokaryotes: cyanobacterial 2-cys peroxiredoxins sensitive to oxidative stress.in eukaryotic organisms, hydrogen peroxide has a dual effect; it is potentially toxic for the cell but also has an important signaling activity. according to the previously proposed floodgate hypothesis, the signaling activity of hydrogen peroxide in eukaryotes requires a transient increase in its concentration, which is due to the inactivation by overoxidation of 2-cys peroxiredoxin (2-cys prx). sensitivity to overoxidation depends on the structural gglg and yf motifs present in eukaryotic 2-cy ...201020736168
obstacles of multiplex real-time pcr for bacterial 16s rdna: primer specifity and dna decontamination of taq polymerase.background: the detection of a broad range of bacteria by pcr is applied for the screening of blood and blood products with special attention to platelet concentrates. for practical use it is desirable that detection systems include gram-positive, gram-negative and non-gram-stainable bacteria. it is quite challenging to achieve high sensitivity along with a clear negative control with pcr reagents, because especially taq polymerase is contaminated with traces of bacterial dna. methods: bacterial ...201020737013
diversity and abundance of zoonotic pathogens and indicators in manures of feedlot cattle in australia.the occurrence of 10 pathogens and three fecal indicators was assessed by quantitative pcr in manures of australian feedlot cattle. most samples tested positive for one or more pathogens. for the dominant pathogens campylobacter jejuni, listeria monocytogenes, giardia spp., cryptosporidium spp., and eaea-positive escherichia coli, 10² to 10⁷ genome copies g⁻¹ (dry weight) manure were recovered.201020802080
transcriptional response of leptospira interrogans to iron limitation and characterization of a perr homolog.leptospirosis is a globally significant zoonosis caused by leptospira spp. iron is essential for growth of most bacterial species. since iron availability is low in the host, pathogens have evolved complex iron acquisition mechanisms to survive and establish infection. in many bacteria, expression of iron uptake and storage proteins is regulated by fur. l. interrogans encodes four predicted fur homologs; we have constructed a mutation in one of these, la1857. we conducted microarray analysis to ...201020805337
mutations affecting leptospira interrogans lipopolysaccharide attenuate virulence.leptospira interrogans is the causative agent of leptospirosis. lipopolysaccharide (lps) is the major outer membrane component of l. interrogans. it is the dominant antigen recognized during infection and the basis for serological classification. the structure of lps and its role in pathogenesis are unknown. we describe two defined mutants of l. interrogans serovar manilae with transposon insertions in the lps locus. mutant m895 was disrupted in gene la1641 encoding a protein with no known homol ...201020807198
enhanced determination of streptococcus pneumoniae serotypes associated with invasive disease in laos by using a real-time polymerase chain reaction serotyping assay with cerebrospinal fluid.a prospective hospital-based study was undertaken to define the incidence of invasive pneumococcal disease (ipd) and circulating serotypes in laos. of 10,799 patients with hemocultures and 353 patients with cerebrospinal fluid samples, 0.21% and 5.4%, respectively, were positive for streptococcus pneumoniae, giving a total of 35 ipd patients. we developed a real-time polymerase chain reaction to detect serotypes represented in the 13-valent pneumococcal vaccine. a blinded evaluation comparing se ...201020810803
the ompl37 surface-exposed protein is expressed by pathogenic leptospira during infection and binds skin and vascular elastin.pathogenic leptospira spp. shed in the urine of reservoir hosts into freshwater can be transmitted to a susceptible host through skin abrasions or mucous membranes causing leptospirosis. the infection process involves the ability of leptospires to adhere to cell surface and extracellular matrix components, a crucial step for dissemination and colonization of host tissues. therefore, the elucidation of novel mediators of host-pathogen interaction is important in the discovery of virulence factors ...201020844573
evidence for a novel marine harmful algal bloom: cyanotoxin (microcystin) transfer from land to sea otters."super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrate ...201020844747
serum lipoproteins attenuate macrophage activation and toll-like receptor stimulation by bacterial lipoproteins.chlamydia trachomatis was previously shown to express a lipoprotein, the macrophage infectivity potentiator (mip), exposed at the bacterial surface, and able to stimulate human primary monocytes/macrophages through toll like receptor (tlr)2/tlr1/tlr6, and cd14. in pma-differentiated thp-1 cells the proinflammatory activity of mip was significantly higher in the absence than in the presence of serum. the present study aims to investigate the ability of different serum factors to attenuate mip pro ...201020846396
cellular architecture of treponema pallidum: novel flagellum, periplasmic cone, and cell envelope as revealed by cryo electron tomography.high-resolution cryo electron tomography (cryo-et) was utilized to visualize treponema pallidum, the causative agent of syphilis, at the molecular level. three-dimensional (3d) reconstructions from 304 infectious organisms revealed unprecedented cellular structures of this unusual member of the spirochetal family. high-resolution cryo-et reconstructions provided detailed structures of the cell envelope, which is significantly different from that of gram-negative bacteria. the 4-nm lipid bilayer ...201020850455
in vitro sensitivity and resistance of 46 leptospira strains isolated from rats in the philippines to 14 antimicrobial agents.the in vitro susceptibilities of 46 leptospira isolates from rats to 14 antimicrobial agents were tested. all of the strains were found to be sensitive to ampicillin, cefotaxime, ciprofloxacin, norfloxacin, doxycycline, erythromycin, and streptomycin. in contrast, the tested isolates showed resistance to amphotericin b, 5-fluorouracil, fosfomycin, trimethoprim, sulfamethoxazole, neomycin, and vancomycin. these findings will help in selecting effective and ineffective antimicrobials for treatment ...201020855741
leptospira as an emerging pathogen: a review of its biology, pathogenesis and host immune responses.leptospirosis, the most widespread zoonosis in the world, is an emerging public health problem, particularly in large urban centers of developing countries. several pathogenic species of the genus leptospira can cause a wide range of clinical manifestations, from a mild, flu-like illness to a severe disease form characterized by multiorgan system complications leading to death. however, the mechanisms of pathogenesis of leptospira are largely unknown. this article will address the animal models ...201020860485
a phenomenological model for predicting melting temperatures of dna sequences.we report here a novel method for predicting melting temperatures of dna sequences based on a molecular-level hypothesis on the phenomena underlying the thermal denaturation of dna. the model presented here attempts to quantify the energetic components stabilizing the structure of dna such as base pairing, stacking, and ionic environment which are partially disrupted during the process of thermal denaturation. the model gives a pearson product-moment correlation coefficient (r) of approximately ...201020865157
visual proteomics.visual proteomics attempts to generate molecular atlases by providing the position and angular orientation of protein complexes inside of cells. this is accomplished by template matching (pattern recognition), a cross-correlation-based process that matches the structure of a specific protein complex to the densities of the whole volume or subvolume of a cell, that is typically acquired by cryoelectron tomography. thereby, a search is performed that scans the entire volume for structural template ...201020888477
a low molecular weight lipopolysaccharide antigen preparation reactive to acute leptospirosis heterologous sera.there is a need for identification of new infection markers against common leptospira isolates in malaysia. to achieve this goal, seven-day-old cultures of leptospira interrogans serogroup icterohemorrhagiae (l44) and leptospira interrogans serogroup javanica (l55) were used for antigen preparation by sequential extraction method using 40 mm tris, 8m urea and 2m thiourea. immunoblot analysis of the antigens were performed using serum samples from 46 local patients with confirmed acute leptospiro ...201020962722
leptospirosis in free-ranging endangered european mink (mustela lutreola) and other small carnivores (mustelidae, viverridae) from southwestern france.to study the possible role of disease in the decline of endangered european mink (mustela lutreola), we conducted a survey of antibody prevalence and renal carriage of pathogenic leptospira (leptospira interrogans sensu lato) using serum and kidney samples collected from 1990 to 2007 from several free-ranging small carnivores and farmed american mink (mustela vison) in southwestern france. an indirect microscopic agglutination test using a panel of 16 serovars belonging to 6 serogroups (australi ...201020966265
serologic evaluation of new zealand sea lions for exposure to brucella and leptospira spp.a serologic survey of anti-brucella and antileptospiral antibodies was conducted on 147 adult, female new zealand sea lions (phocarctos hookeri). most sea lions (n=138) were sampled at sandy bay, enderby island, auckland islands (50°30's, 166°17'e), january 2000-march 2005. nine were sampled at otago, new zealand (46°0's, 170°40'e); four in april 2008 and five in march 2009. serum from one of the enderby island females was weakly positive for antibodies to brucella abortus using the competitive ...201020966283
the crystal structure of the leptospiral hypothetical protein lic12922 reveals homology with the periplasmic chaperone sura.leptospirosis is a world spread zoonosis caused by members of the genus leptospira. although leptospires were identified as the causal agent of leptospirosis almost 100 years ago, little is known about their biology, which hinders the development of new treatment and prevention strategies. one of the several aspects of the leptospiral biology not yet elucidated is the process by which outer membrane proteins (omps) traverse the periplasm and are inserted into the outer membrane. the crystal stru ...201020970503
leptospirosis: an unusual cause of ards.severe leptospirosis usually associates shock, jaundice, renal failure, and thrombocytopenia. massive hemoptysis due to diffuse alveolar haemorrhage may rarely occur leading to an acute respiratory failure and multiple organ failure. we present the case of an acute respiratory distress syndrome caused by a severe leptospirosis. the severity of the respiratory failure contrasted with the absence of significant liver or renal dysfunction. bedside open lung biopsy was only consistent with a postinf ...201020981324
expanding the genetic toolbox for leptospira species by generation of fluorescent bacteria.our knowledge of the genetics and molecular basis of the pathogenesis associated with leptospira, in comparison to those of other bacterial species, is very limited. an improved understanding of pathogenic mechanisms requires reliable genetic tools for functional genetic analysis. here, we report the expression of gfp and mrfp1 genes under the control of constitutive spirochetal promoters in both saprophytic and pathogenic leptospira strains. we were able to reliably measure the fluorescence of ...201021037299
transcriptional responses of leptospira interrogans to host innate immunity: significant changes in metabolism, oxygen tolerance, and outer membrane.leptospira interrogans is the major causative agent of leptospirosis. phagocytosis plays important roles in the innate immune responses to l. interrogans infection, and l. interrogans can evade the killing of phagocytes. however, little is known about the adaptation of l. interrogans during this process.201021049008
characterization of novel bovine gastrointestinal tract treponema isolates and comparison with bovine digital dermatitis treponemes.this study aimed to isolate and characterize treponemes present in the bovine gastrointestinal (gi) tract and compare them with bovine digital dermatitis (bdd) treponemes. seven spirochete isolates were obtained from the bovine gi tract, which, on the basis of 16s rrna gene comparisons, clustered within the genus treponema as four novel phylotypes. one phylotype was isolated from several different gi tract regions, including the omasum, colon, rumen, and rectum. these four phylotypes could be di ...201021057019
characterization of novel bovine gastrointestinal tract treponema isolates and comparison with bovine digital dermatitis treponemes.this study aimed to isolate and characterize treponemes present in the bovine gastrointestinal (gi) tract and compare them with bovine digital dermatitis (bdd) treponemes. seven spirochete isolates were obtained from the bovine gi tract, which, on the basis of 16s rrna gene comparisons, clustered within the genus treponema as four novel phylotypes. one phylotype was isolated from several different gi tract regions, including the omasum, colon, rumen, and rectum. these four phylotypes could be di ...201021057019
the photosensor protein ppr of rhodocista centenaria is linked to the chemotaxis signalling pathway.rhodocista centenaria is a phototrophic α-proteobacterium exhibiting a phototactic behaviour visible as colony movement on agar plates directed to red light. as many phototrophic purple bacteria r. centenaria possesses a soluble photoactive yellow protein (pyp). it exists as a long fusion protein, designated ppr, consisting of three domains, the pyp domain, a putative bilin binding domain (bbd) and a histidine kinase domain (pph). the ppr protein is involved in the regulation of polyketide synth ...201021062468
manganese binds to clostridium difficile fbp68 and is essential for fibronectin binding.clostridium difficile is an etiological agent of pseudomembranous colitis and antibiotic-associated diarrhea. adhesion is the crucial first step in bacterial infection. thus, in addition to toxins, the importance of colonization factors in c. difficile-associated disease is recognized. in this study, we identified fbp68, one of the colonization factors that bind to fibronectin (fn), as a manganese-binding protein (k(d) = 52.70 ± 1.97 nm). furthermore, the conformation of fbp68 changed dramatical ...201021062746
manganese binds to clostridium difficile fbp68 and is essential for fibronectin binding.clostridium difficile is an etiological agent of pseudomembranous colitis and antibiotic-associated diarrhea. adhesion is the crucial first step in bacterial infection. thus, in addition to toxins, the importance of colonization factors in c. difficile-associated disease is recognized. in this study, we identified fbp68, one of the colonization factors that bind to fibronectin (fn), as a manganese-binding protein (k(d) = 52.70 ± 1.97 nm). furthermore, the conformation of fbp68 changed dramatical ...201021062746
comparison of conventional, nested, and real-time quantitative pcr for diagnosis of scrub typhus.orientia tsutsugamushi is the causative agent of scrub typhus. for the diagnosis of scrub typhus, we investigated the performances of conventional pcr (c-pcr), nested pcr (n-pcr), and real-time quantitative pcr (q-pcr) targeting the o. tsutsugamushi-specific 47-kda gene. to compare the detection sensitivities of the three techniques, we used two template systems that used plasmid dna (plasmid detection sensitivity), including a partial region of the 47-kda gene, and genomic dna (genomic detectio ...201021068287
acute parvovirus b19 infection causes nonspecificity frequently in borrelia and less often in salmonella and campylobacter serology, posing a problem in diagnosis of infectious arthropathy.several infectious agents may cause arthritis or arthropathy. for example, infection with borrelia burgdorferi, the etiologic agent of lyme disease, may in the late phase manifest as arthropathy. infections with campylobacter, salmonella, or yersinia may result in a postinfectious reactive arthritis. acute infection with parvovirus b19 (b19v) may likewise initiate transient or chronic arthropathy. all these conditions may be clinically indistinguishable from rheumatoid arthritis. here, we presen ...201021106777
acute parvovirus b19 infection causes nonspecificity frequently in borrelia and less often in salmonella and campylobacter serology, posing a problem in diagnosis of infectious arthropathy.several infectious agents may cause arthritis or arthropathy. for example, infection with borrelia burgdorferi, the etiologic agent of lyme disease, may in the late phase manifest as arthropathy. infections with campylobacter, salmonella, or yersinia may result in a postinfectious reactive arthritis. acute infection with parvovirus b19 (b19v) may likewise initiate transient or chronic arthropathy. all these conditions may be clinically indistinguishable from rheumatoid arthritis. here, we presen ...201021106777
first isolation and direct evidence for the existence of large small-mammal reservoirs of leptospira sp. in madagascar.leptospirosis has long been a major public health concern in the southwestern indian ocean. however, in madagascar, only a few, old studies have provided indirect serological evidence of the disease in humans or animals.201021124843
high yield expression of leptospirosis vaccine candidates liga and lipl32 in the methylotrophic yeast pichia pastoris.leptospirosis, a zoonosis caused by leptospira spp., is recognized as an emergent infectious disease. due to the lack of adequate diagnostic tools, vaccines are an attractive intervention strategy. recombinant proteins produced in escherichia coli have demonstrated promising results, albeit with variable efficacy. pichia pastoris is an alternative host with several advantages for the production of recombinant proteins.201021134266
investigation of localisation of leptospira spp. in uterine and fetal tissues of non-pregnant and pregnant farmed deer.to find evidence for localisation in the uterus, and fetal infection, of leptospira spp. in farmed deer in the lower north island of new zealand during and shortly after the breeding season.201021151213
characterization of leptospiral proteins that afford partial protection in hamsters against lethal challenge with leptospira interrogans.leptospirosis is a worldwide zoonosis caused by pathogenic leptospira. the whole-genome sequence of leptospira interrogans serovar copenhageni together with bioinformatic tools allow us to search for novel antigen candidates suitable for improved vaccines against leptospirosis. this study focused on three genes encoding conserved hypothetical proteins predicted to be exported to the outer membrane. the genes were amplified by pcr from six predominant pathogenic serovars in brazil. the genes were ...201020558583
different outcomes of experimental leptospiral infection in mouse strains with distinct genotypes.the mouse disease model has the advantage of a broad array of immunological and genetic tools available for basic research. some studies on transgenic and/or mutant mouse strains as models for experimental leptospirosis have been reported; however, the wider use of such models is hampered by a poor understanding of the outcome of experimental leptospiral infection among the different mouse strains available. here, the outcome of infection by a virulent strain of leptospira interrogans serogroup ...201020558584
structural insights into the catalytic mechanism of bacterial guanosine-diphospho-d-mannose pyrophosphorylase and its regulation by divalent ions.gmp catalyzes the formation of gdp-man, a fundamental precursor for protein glycosylation and bacterial cell wall and capsular polysaccharide biosynthesis. crystal structures of gmp from the thermophilic bacterium thermotoga maritima in the apo form, in complex with the substrates mannose-1-phosphate or gtp and bound with the end product gdp-man in the presence of the essential divalent cation mg(2+), were solved in the 2.1-2.8 a resolution range. the t. maritima gmp molecule is organized in two ...201020573954
in vitro identification of novel plasminogen-binding receptors of the pathogen leptospira interrogans.leptospirosis is a multisystem disease caused by pathogenic strains of the genus leptospira. we have reported that leptospira are able to bind plasminogen (plg), to generate active plasmin in the presence of activator, and to degrade purified extracellular matrix fibronectin.201020582320
characterization of a lipopolysaccharide mutant of leptospira derived by growth in the presence of an anti-lipopolysaccharide monoclonal antibody.a lipopolysaccharide mutant of leptospira interrogans (laimut) was obtained by growth in the presence of an agglutinating monoclonal antibody (mab) against lipopolysaccharide. agglutination reactions with anti-lipopolysaccharide mabs and polyclonal antibodies showed that laimut had lost some serogroup icterohaemorrhagiae agglutinating epitopes. however, laimut displayed an increased reactivity to antisera against related serogroups, suggesting that the disruption of some lipopolysaccharide epito ...201020584080
the yellow fever vaccine: a history.after failed attempts at producing bacteria-based vaccines, the discovery of a viral agent causing yellow fever and its isolation in monkeys opened new avenues of research. subsequent advances were the attenuation of the virus in mice and later in tissue culture; the creation of the seed lot system to avoid spontaneous mutations; the ability to produce the vaccine on a large scale in eggs; and the removal of dangerous contaminants. an important person in the story is max theiler, who was profess ...201020589188
isolation of leptospira interrogans from suburban rats in tandil, buenos aires, argentina.the main objective of this study was to investigate the role of wild rodents as leptospira spp. reservoirs in a suburban area of tandil city, buenos aires province (argentina), where a person had died due to pulmonary leptospirosis. the specific objectives were: to estimate the rodent density near the patient's home, to determine the serological prevalence and isolation of leptospirosis from wild rodents, and to identify the isolated strains. the area examined was a suburban neighbourhood in tan ...201020589335
prevalence of leptospira interrogans antibodies in free-ranging tayassu pecari of the southern pantanal, brazil, an ecosystem where wildlife and cattle interact.we surveyed a wild population of white-lipped peccaries (tayassu pecari) in the brazilian pantanal for evidence of leptospira interrogans. serum samples from 71 free-ranging t. pecari were obtained between 2003 and 2005 in the southern pantanal of mato grosso do sul state. we used microscopic microagglutination to test for antibodies against 14 l. interrogans serovars (antibody titers ≥ 1:100 were considered seropositive). seventy percent of captured animals tested positive for leptospirosis ant ...201020596776
an alternative route for udp-diacylglucosamine hydrolysis in bacterial lipid a biosynthesis.the outer leaflet of the outer membranes of gram-negative bacteria is composed primarily of lipid a, the hydrophobic anchor of lipopolysaccharide. like escherichia coli, most gram-negative bacteria encode one copy of each of the nine genes required for lipid a biosynthesis. an important exception exists in the case of the fourth enzyme, lpxh, a peripheral membrane protein that hydrolyzes udp-2,3-diacylglucosamine to form 2,3-diacylglucosamine 1-phosphate and ump by catalyzing the attack of water ...201020608695
the hpk2-rrp2 two-component regulatory system of treponema denticola: a potential regulator of environmental and adaptive responses.treponema denticola levels in the gingival crevice become elevated as periodontal disease develops. oral treponemes may account for as much as 40% of the total bacterial population in the periodontal pocket. the stimuli that trigger enhanced growth of t. denticola, and the mechanisms associated with the transmission of these signals, remain to be defined. we hypothesize that the t. denticola open reading frames tde1970 (histidine kinase) and tde1969 (response regulator) constitute a functional t ...201020618698
experimental leptospira interrogans serovar kennewicki infection of horses.little information is available about experimental induction of leptospirosis in horses.201020649749
identification and characterization of ompa-like proteins as novel vaccine candidates for leptospirosis.leptospira is an important infectious gram-negative bacterium causing leptospirosis in mammals. outer membrane proteins (omps) are key molecules in the interface between the cell and its environment. a group of putative leptospiral outer membrane proteins with an ompa-like domain, comprising lp0056, lp0222, lp3615, lp3685, lp4337 and lbp328, were identified by bioinformatic methods and expressed as gst-tag fusion proteins. all these recombinant proteins were screened for immune-protective potent ...201020064477
of guinea pigs and men--an unusual case of jaundice.a 21-year-old male presented at the emergency room with jaundice, itching, dry cough, malaise and weight loss of 10 kg during the preceding four weeks. eighteen months earlier, the patient had suffered an automobile accident leading to polytrauma. serological markers for viral or other causes of hepatitis were absent. for suspected secondary sclerosing cholangitis, ultrasound and ercp were performed but failed to reveal pathological findings. a liver biopsy showed cholestatic liver disease witho ...201020072994
leptospira wolffii, a potential new pathogenic leptospira species detected in human, sheep and dog.leptospirosis is the most common zoonotic disease, which is transmitted to humans through contaminated water or direct exposure to the urine of infected animals. in this study, the presence and prevalence of leptospira species in the infected samples of human (n=369) and sheep (n=75) sera and also dogs' urine (n=150), collected from four provinces of iran, were investigated by using nested-pcr/rflp assay followed by sequencing analysis. nested-pcr assay detected that 98/369 (26.5%) human, 13/75 ...201020074666
differential cytokine gene expression according to outcome in a hamster model of leptospirosis.parameters predicting the evolution of leptospirosis would be useful for clinicians, as well as to better understand severe leptospirosis, but are scarce and rarely validated. because severe leptospirosis includes septic shock, similarities with predictors evidenced for sepsis and septic shock were studied in a hamster model.201020076757
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