Publications

leptospirosis.	leptospirosis is a worldwide zoonotic infection with a much greater incidence in tropical regions and has now been identified as one of the emerging infectious diseases. the epidemiology of leptospirosis has been modified by changes in animal husbandry, climate, and human behavior. resurgent interest in leptospirosis has resulted from large outbreaks that have received significant publicity. the development of simpler, rapid assays for diagnosis has been based largely on the recognition that ear ...	2001	11292640
first evidence for gene replacement in leptospira spp. inactivation of l. biflexa flab results in non-motile mutants deficient in endoflagella.	leptospira spp. offer many advantages as model bacteria for the study of spirochaetes. however, homologous recombination between introduced dna and the corresponding chromosomal loci has never been demonstrated. a unique feature of spirochaetes is the presence of endoflagella between the outer membrane sheath and the cell cylinder. we chose the flab flagellin gene, constituting the flagellar core, as a target for gene inactivation in the saprophyte leptospira biflexa. the amino acid sequence of ...	2001	11298286
brachyspira (serpulina) hyodysenteriae gyrb mutants and interstrain transfer of coumermycin a(1) resistance.	to further develop genetic techniques for the enteropathogen brachyspira hyodysenteriae, the gyrb gene of this spirochete was isolated from a lambdazapii library of strain b204 genomic dna and sequenced. the putative protein encoded by this gene exhibited up to 55% amino acid sequence identity with gyrb proteins of various bacterial species, including other spirochetes. b. hyodysenteriae coumermycin a(1)-resistant (cn(r)) mutant strains, both spontaneous and uv induced, were isolated by plating ...	2001	11319078
direct synthesis of beta-mannans. a hexameric [-->3)-beta-d-man-(1](3) subunit of the antigenic polysaccharides from leptospira biflexa and the octameric (1-->2)-linked beta-d-mannan of the candida albicans phospholipomannan. x-ray crystal structure of a protected tetramer.		2001	11403627
use of locally isolated saprophytic leptospira strain for serological testing of human leptospirosis.	a saprophytic leptospira isolate recovered from tap water was utilized for serological testing. one hundred-twenty serum samples comprising 55 cases from puo/febrile jaundice and 65 samples from apparently healthy individuals were tested by mat and ha using this environmental saprophytic strain and the results compared with that of leptospira biflexa semaranga patoc, the standard saprophytic strain commonly employed for sero-diagnosis of leptospirosis. the mat data showed 96.4 per cent correlati ...	2000	11407004
rpob sequence analysis of cultured tropheryma whippelii.	until recently no isolate of tropheryma whippelii was available, and therefore genetic studies were limited to those based on pcr amplification of conserved genes. in this study we determined the nucleotide sequence of rpob (encoding the beta-subunit of rna polymerase) from a cultured strain of t. whippelii using degenerate consensus pcr and genome walking. the t. whippelii rpob consists of 3,657 bp with a 50.4% gc content and encodes 1,218 amino acids with a calculated molecular mass of 138 kda ...	2001	11427549
transduction by phibb-1, a bacteriophage of borrelia burgdorferi.	we previously described a bacteriophage of the lyme disease agent borrelia burgdorferi designated phibb-1. this phage packages the host complement of the 32-kb circular plasmids (cp32s), a group of homologous molecules found throughout the genus borrelia. to demonstrate the ability of phibb-1 to package and transduce dna, a kanamycin resistance cassette was inserted into a cloned fragment of phage dna, and the resulting construct was transformed into b. burgdorferi ca-11.2a cells. the kan casset ...	2001	11466280
first evidence for a restriction-modification system in leptospira sp.	the le1 leptophage exhibited a host range restricted to the saprophytic leptospira biflexa [saint girons et al., res. microbiol. 141 (1990) 1131-1133] and mainly to the patoc 1 strain (hereafter called pfra) kept in the paris, france collection. results of titration of le1 lysates indicated the presence of a host-controlled modification and restriction system within pusa (patoc 1 strain maintained in the morgantown, wv, usa collection) that was absent in pfra. because genomic dna of pital (patoc ...	2001	11470352
citrate synthase gene sequence: a new tool for phylogenetic analysis and identification of ehrlichia.	the sequence of the citrate synthase gene (glta) of 13 ehrlichial species (ehrlichia chaffeensis, ehrlichia canis, ehrlichia muris, an ehrlichia species recently detected from ixodes ovatus, cowdria ruminantium, ehrlichia phagocytophila, ehrlichia equi, the human granulocytic ehrlichiosis [hge] agent, anaplasma marginale, anaplasma centrale, ehrlichia sennetsu, ehrlichia risticii, and neorickettsia helminthoeca) have been determined by degenerate pcr and the genome walker method. the ehrlichial ...	2001	11526124
evaluation of recombinant leptospira antigen-based enzyme-linked immunosorbent assays for the serodiagnosis of leptospirosis.	there is an urgent need for development of new serodiagnostic strategies for leptospirosis, an emerging zoonosis with worldwide distribution. we have evaluated the diagnostic utility of five recombinant antigens in enzyme-linked immunosorbent assays (elisas) for serodiagnosis of leptospirosis. sera from 50 healthy residents of a high-incidence region were used to determine cutoff values for 96% specificity. in paired sera from 50 cases of leptospirosis confirmed by the microscopic agglutination ...	2001	11526167
killing effect and antitoxic activity of the leptospira interrogans toxin-antitoxin system in escherichia coli.	we report the first evidence of a chromosome-encoded toxin-antitoxin locus in spirochetes. this locus has been found in the pathogenic spirochete leptospira interrogans and exhibits homologies with the pem/chp loci. the l. interrogans chp locus consists of two genes: chpk (for "killer protein") and its upstream partner chpi (for "inhibitory protein"). expression of chpk in escherichia coli results in the inhibition of bacterial growth. the coexpression of chpi neutralizes chpk toxicity. by south ...	2001	11591696
identification of the hemolysis-associated protein 1 as a cross-protective immunogen of leptospira interrogans by adenovirus-mediated vaccination.	new vaccine strategies are needed for the prevention of leptospirosis, a widespread human and animal disease caused by pathogenic leptospires. our previous work determined that a protein leptospiral extract conferred cross-protection in a gerbil model of leptospirosis. the 31- to 34-kda protein fraction of leptospira interrogans serovar autumnalis was shown sufficient for this purpose. in the present study, n-terminal sequencing of a 32-kda fraction and southern blotting of genomic dna with corr ...	2001	11598056
natural rifampin resistance in treponema spp. correlates with presence of n531 in rpob rif cluster i.		2001	11702716
molecular characterization of thermoinduced immunogenic proteins q1p42 and hsp15 of leptospira interrogans.	leptospira interrogans is a mammalian pathogen which must adapt to a range of new environmental conditions including temperature change when it infects new hosts. in vitro studies of organisms cultured at 30 degrees c and shifted to 37 degrees c for 5 to 7 days have confirmed that synthesis of several proteins involved in equine infection is regulated in response to temperature change (j. e. nally, j. f. timoney, and b. stevenson, infect. immun. 69:400-404, 2001). in order to specifically identi ...	2001	11705941
novel 45-kilodalton leptospiral protein that is processed to a 31-kilodalton growth-phase-regulated peripheral membrane protein.	leptospiral protein antigens are of interest as potential virulence factors and as candidate serodiagnostic and immunoprotective reagents. we identified leptospiral protein antigens by screening a genomic expression library with serum from a rabbit hyperimmunized with formalin-killed, virulent leptospira kirschneri serovar grippotyphosa. genes expressing known outer membrane lipoproteins lipl32 and lipl41, the heat shock protein groel, and the alpha, beta, and beta' subunits of rna polymerase we ...	2002	11748198
inactivation of the spirochete reca gene results in a mutant with low viability and irregular nucleoid morphology.	recently, we have shown the first evidence for allelic exchange in leptospira spp. by using the same methodology, the cloned reca of leptospira biflexa was interrupted by a kanamycin resistance cassette, and the mutated allele was then introduced into the l. biflexa chromosome by homologous recombination. the reca double-crossover mutant showed poor growth in liquid media and was considerably more sensitive to dna-damaging agents such as mitomycin c and uv light than the wild-type strain. the ef ...	2002	11751822
peripheral blood mononuclear cell activation induced by leptospira interrogans glycolipoprotein.	leptospira interrogans glycolipoprotein (glp) has been implicated in pathological and functional derangement seen in leptospirosis. the goal of this study was to evaluate glp's ability to induce cellular activation, as assessed by cytokine production and expression of surface activation markers. glp extracted from either pathogenic l. interrogans serovar copenhageni or nonpathogenic leptospira biflexa serovar patoc (glpp) was used to stimulate peripheral blood mononuclear cell cultures from heal ...	2002	11895929
molecular typing of papillomatous digital dermatitis-associated treponema isolates based on analysis of 16s-23s ribosomal dna intergenic spacer regions.	papillomatous digital dermatitis (pdd), an emerging infectious disease of cattle, is characterized by painful, ulcerative foot lesions. the detection of high numbers of invasive spirochetes in pdd lesions suggests an important role for these organisms in the pathogenesis of pdd. pdd-associated spirochetes have phenotypic characteristics consistent with members of the genus treponema: partial 16s ribosomal dna (rdna) sequence analysis of clonal isolates from california cattle showed that they com ...	2002	12202594
[alignment of dna sequences of ompl1 genes of insert fragment of recombinant plasmid, pdc38 of l. interrogans serovar lai and l. kirschneri].	in a previous study a genomic library of l. interrogans serovar lai was constructed by the present authors. hybridization analysis (in situ, dot blot, southern blot) with the dna fragment containing ompl1 (alpha-32p labeled) was performed. one of positive clones designated pdc38, was analyzed with 9 restriction enzymes (ecori, bam hi, hind iii, bgl, xbali, scai, kpni, psti, dra ii). dna hybridization was applied to analyze the homology of the recombinant fragment of ompl1 with the dna of 18 stra ...	1999	12212270
rapid translocation of polarized mdck cell monolayers by leptospira interrogans, an invasive but nonintracellular pathogen.	pathogenic spirochetes of the genus leptospira are a major cause of human zoonotic infectious disease worldwide. after gaining entry through the skin, the organism causes disease by hematogenously disseminating to multiple organs. the mechanism by which it penetrates the mammalian cell barriers to disseminate is not well understood. in this study, we used a low-passage-number isolate of leptospira interrogans to elucidate the invasive potential of this spirochete. quantification of bacteria by d ...	2002	12438371
leptospires are killed in vitro by both oxygen-dependent and -independent reactions.	this study reports for the first time that leptospires are killed by h(2)o(2) and by low-molecular-weight primary granule components, which are agents normally released by neutrophils upon stimulation. although both pathogenic and nonpathogenic strains were sensitive to h(2)o(2)-mediated killing, nonpathogenic organisms were found to be more susceptible. in addition, the killing of leptospires by h(2)o(2) was found to be independent of the presence of the neutrophil primary granule component mye ...	2002	12438405
low-stringency single specific primer pcr for identification of leptospira.	thirty-five leptospira serovars from the species leptospira interrogans, leptospira borgpetersenii, leptospira santarosai, leptospira kirschneri, leptospira weilii, leptospira biflexa and leptospira meyeri were characterized by the low-stringency single specific primer pcr (lssp-pcr) technique. lssp-pcr analysis was performed to detect dna polymorphisms in a 285 bp dna fragment amplified from genomic dna with g1 and g2 selected primers. similar lssp-pcr profiles were obtained for serovars from t ...	2003	12543918
leptospira spp. possess a complete haem biosynthetic pathway and are able to use exogenous haem sources.	unlike the spirochetes borrelia burgdorferi and treponema pallidum, leptospira spp. contain genes encoding the enzymes for most biosynthetic pathways. in this study, we describe the first haem biosynthetic pathway genes in the order spirochaetales. sequence analysis of the l. interrogans genome shows that all haem biosynthetic genes (hema, heml, hemb, hemc, heme, hemn, hemy and hemh) are clustered in a 15 kb region of the cii secondary chromosome. although no hemd homologue (encoding uroporphyri ...	2003	12864856
identification and evaluation of lps antigen for serodiagnosis of uveitis associated with leptospirosis.	leptospirosis is a widespread zoonotic disease that affects all mammals in different parts of the world. though there are many commercial kits available for the diagnosis of systemic leptospirosis, the nature of the antigen has not been described. therefore, identification of a specific antigen is important. since ocular involvement in leptospirosis has been reported, there is a need to identify and characterize the leptospiral antigen for diagnosis of uveitis associated with past leptospiral in ...	2003	12867560
in vitro susceptibilities of seven leptospira species to traditional and newer antibiotics.	human leptospirosis is generally treated with penicillin or doxycycline. we studied the susceptibilities of 11 serovars (seven species) of leptospira to 14 antibiotics. with the exception of chloramphenicol, all tested agents were at least as potent as penicillin and doxycycline, with the macrolide and ketolide drugs producing the lowest mics (and minimal bactericidal concentrations).	2003	12878533
temperature-dependent hypermutational phenotype in reca mutants of thermus thermophilus hb27.	the reca gene from thermus thermophilus hb27 was cloned and engineered to obtain insertion (reca::kat) and deletion (deltareca) derivatives. transcription of reca in this extreme thermophile was induced by mitomycin c, leading to the synthesis of a monocistronic mrna. this dna damage-mediated induction was dependent on the integrity of reca. in addition to uv sensitivity, the reca mutants of t. thermophilus showed severe pleiotropic defects, ranging from irregular nucleoid condensation and segre ...	2003	12897010
an outbreak of leptospirosis among peruvian military recruits.	acute undifferentiated febrile illnesses are common in tropical developing countries but are difficult to diagnose on clinical grounds alone. leptospirosis is rarely diagnosed, despite evidence that sporadic cases and epidemics continue to occur worldwide. the purpose of this study was to diagnose an outbreak of acute undifferentiated febrile illness among peruvian military recruits that developed after a training exercise in the high jungle rainforest of peru. of 193 military recruits, 78 devel ...	2003	12932097
standardization and stabilization of an extract from leptospira biflexa and its use in the hemolytic test for leptospirosis.		1957	13475879
isolation and characterization of muramic acid from two spirochaetes: borrelia duttoni and leptospira biflexa.		1963	14043185
differentiation of pathogenic and saprophytic leptospires with 8-azaguanine.	johnson, russell c. (university of minnesota, minneapolis), and palmer rogers. differentiation of pathogenic and saprophytic leptospires with 8-azaguanine. j. bacteriol. 88:1618-1623. 1964.-the use of the purine analogue, 8-azaguanine, as a differential agent for the separation of pathogenic and saprophytic leptospires was investigated. growth of strains of the saprophyte leptospira biflexa was almost insensitive to the bacteriostatic action of 8-azaguanine at concentrations varying from 25 to 6 ...	1964	14244050
[demarcation of saprophytic and pathogenic properties of leptospira biflexa].		1964	14266480
the use of leptospira biflexa patoc antigen in field investigations of leptospirosis.	hitherto the laboriousness of serological procedures for the laboratory diagnosis of leptospirosis has somewhat limited their usefulness. the authors of this paper report on a simple and sensitive genus-specific serological test for this disease that is within the capabilities of ordinary diagnostic laboratories. they describe the organization and results of a trial carried out in romania in 1962 of a complement-fixation (cf) test in leptospirosis in which an antigen derived from the patoc i str ...	1964	14267745
transamination in leptospira biflexa.		1959	14421278
host-inducible immunogenic sphingomyelinase-like protein, lk73.5, of leptospira interrogans.	leptospira interrogans causes a variety of clinical syndromes in animals and humans. although much information has accumulated on the importance of leptospiral lipopolysaccharide in protective antibody responses, relatively little is known about proteins that participate in immune responses. identification of those proteins induced only in the host is particularly difficult. using a novel double-antibody screen designed to identify clones in a gene library of l. interrogans serovar pomona expres ...	2004	14742516
[distribution of virulence associated genes among strains of leptospira].	to analyze factors related to the virulence associated genes of leptospires.	2003	14761630
determination of the genus-specific antigens in outer membrane proteins from the strains of leptospira interrogans and leptospira biflexa with different virulence.	to determine the existence of genus-specific antigens in outer membrane proteins (omps) of leptospira with different virulence.	2004	14994438
transgenic expression of reca of the spirochetes borrelia burgdorferi and borrelia hermsii in escherichia coli revealed differences in dna repair and recombination phenotypes.	after unsuccessful attempts to recover a viable reca-deficient mutant of the lyme borreliosis agent borrelia burgdorferi, we characterized the functional activities of reca of b. burgdorferi, as well as reca of the relapsing fever spirochete borrelia hermsii and the free-living spirochete leptospira biflexa, in a reca mutant of escherichia coli. as a control, e. coli reca was expressed from the same plasmid vector. dna damage repair activity was assessed after exposure of the transgenic cells to ...	2004	15060027
functional properties of borrelia burgdorferi reca.	functions of the borrelia burgdorferi reca protein were investigated in escherichia coli reca null mutants. complementation with b. burgdorferi reca increased survival of e. coli reca mutants by 3 orders of magnitude at a uv dose of 2,000 microj/cm(2). the viability at this uv dose was about 10% that provided by the homologous reca gene. expression of b. burgdorferi reca resulted in survival of e. coli at levels of mitomycin c that were lethal to noncomplemented hosts. b. burgdorferi reca was as ...	2004	15060028
new approach for serological testing for leptospirosis by using detection of leptospira agglutination by flow cytometry light scatter analysis.	leptospirosis is considered an important reemerging infectious disease worldwide. the standard and most widespread method for the diagnosis of leptospirosis is the microscopic agglutination test (mat). this test is laborious and time-consuming, and the interpretation of the results is subjective. in the present work we describe an application of flow cytometry (fcm) as a tool for the serological diagnosis of leptospirosis. the analysis is based on the sensitivity of fcm to the size and shape of ...	2004	15071025
molecular evolution and mosaicism of leptospiral outer membrane proteins involves horizontal dna transfer.	leptospires belong to a genus of parasitic bacterial spirochetes that have adapted to a broad range of mammalian hosts. mechanisms of leptospiral molecular evolution were explored by sequence analysis of four genes shared by 38 strains belonging to the core group of pathogenic leptospira species: l. interrogans, l. kirschneri, l. noguchii, l. borgpetersenii, l. santarosai, and l. weilii. the 16s rrna and lipl32 genes were highly conserved, and the lipl41 and ompl1 genes were significantly more v ...	2004	15090524
environmental exposure and leptospirosis, peru.	human infection by leptospires has highly variable clinical manifestations, which range from subclinical infection to fulminant disease. we conducted a population-based, cross-sectional seroepidemiologic study in peru to determine potential relationships of environmental context to human exposure to leptospira and disease associated with seroconversion. three areas were studied: a flooded, urban slum in the peruvian amazon city of iquitos; rural, peri-iquitos villages; and a desert shantytown ne ...	2004	15207052
isoleucine biosynthesis in leptospira interrogans serotype lai strain 56601 proceeds via a threonine-independent pathway.	three leua-like protein-coding sequences were identified in leptospira interrogans. one of these, the cima gene, was shown to encode citramalate synthase (ec 4.1.3.-). the other two encoded alpha-isopropylmalate synthase (ec 4.1.3.12). expressed in escherichia coli, the citramalate synthase was purified and characterized. although its activity was relatively low, it was strictly specific for pyruvate as the keto acid substrate. unlike the citramalate synthase of the thermophile methanococcus jan ...	2004	15292141
expression of leptospiral immunoglobulin-like protein by leptospira interrogans and evaluation of its diagnostic potential in a kinetic elisa.	the search for novel antigens suitable for improved vaccines and diagnostic reagents against leptospirosis led to the identification of liga and ligb. liga and ligb expression were not detectable at the translation level but were detectable at the transcription level in leptospires grown in vitro. lig genes were present in pathogenic serovars of leptospira, but not in non-pathogenic leptospira biflexa. the conserved and variable regions of liga and ligb (con, vara and varb) were cloned, expresse ...	2004	15358819
direct chemical synthesis of the beta-mannans: linear and block syntheses of the alternating beta-(1-->3)-beta-(1-->4)-mannan common to rhodotorula glutinis, rhodotorula mucilaginosa, and leptospira biflexa.	two stereocontrolled syntheses of a methyl glycoside of an alternating beta-(1-->4)-beta-(1-->3)-mannohexaose, representative of the mannan from rhodotorula glutinis, rhodotorula mucilaginosa, and leptospira biflexa, are described. both syntheses employ a combination of 4,6-o-benzylidene- and 4,6-o-p-methoxybenzylidene acetal-protected donors to achieve stereocontrolled formation of the beta-mannoside linkage. the first synthesis is a linear one and proceeds with a high degree of stereocontrol t ...	2004	15548005
clinical spectrum of pulmonary involvement in leptospirosis in a region of endemicity, with quantification of leptospiral burden.	pulmonary involvement in leptospirosis remains poorly recognized in regions where it is endemic, despite reports of recent outbreaks and epidemic disease.	2005	15668855
evaluation of lig-based conventional and real time pcr for the detection of pathogenic leptospires.	leptospirosis is globally important infectious disease affecting almost all mammals. pathogenic leptospira encodes immunoglobulin-like protein (lig) that is found to express only during infection. we report the development of conventional and real time pcr assays targeting lig genes of leptospires for the early diagnosis of leptospirosis. sensitivity of the newly designed lig1/lig2 primers for conventional pcr was compared with previously published primers lp1/lp2 and g1/g2. g1/g2 primers amplif ...	2004	15680212
whole-genome analysis of leptospira interrogans to identify potential vaccine candidates against leptospirosis.	leptospirosis is an important global human and veterinary health problem. humans can be infected by exposure to chronically infected animals and their environment. an important focus of the current leptospiral research is the identification of outer membrane proteins (omps). due to their location, leptospiral omps are likely to be relevant in host-pathogen interactions, hence their potential ability to stimulate heterologous immunity. the existing whole-genome sequence of leptospira interrogans ...	2005	15766783
isolation and characterization of feca- and feob-mediated iron acquisition systems of the spirochete leptospira biflexa by random insertional mutagenesis.	the specific mechanisms by which leptospira spp. acquire iron from their ecological niches are unknown. a major factor contributing to our ignorance of spirochetal biology is the lack of methods for genetic analysis of these organisms. in this study, we have developed a system for random transposon mutagenesis of leptospira biflexa using a mariner transposon, himar1. to demonstrate the validity of himar1 in vivo transposon mutagenesis in l. biflexa, a screen of mutants for clones impaired in ami ...	2005	15838052
random insertional mutagenesis of leptospira interrogans, the agent of leptospirosis, using a mariner transposon.	the recent availability of the complete genome sequences of leptospira interrogans, the agent of leptospirosis, has allowed the identification of several putative virulence factors. however, to our knowledge, attempts to carry out gene transfer in pathogenic leptospira spp. have failed so far. in this study, we show that the himar1 mariner transposon permits random mutagenesis in the pathogen l. interrogans. we have identified genes that have been interrupted by himar1 insertion in 35 l. interro ...	2005	15838053
complete nucleotide sequence of the le1 prophage from the spirochete leptospira biflexa and characterization of its replication and partition functions.	the first and, to date, only extrachromosomal circular replicon identified in the spirochete leptospira is the le1 prophage from leptospira biflexa. the 74-kb le1 genome has a gc content of 36%, which is similar to the gc content of leptospira spp. most of the 79 predicted open reading frames (orfs) showed no similarities to known orfs. however 21 orfs appeared to be organized in clusters that could code for head and tail structural proteins and immunity repressor proteins. in addition, the patt ...	2005	15937155
protection against leptospira interrogans sensu lato challenge by dna immunization with the gene encoding hemolysin-associated protein 1.	the use of dna constructs encoding leptospiral proteins is a promising new approach for vaccination against leptospirosis. in previous work we determined that immunization with hemolysis-associated protein 1 (hap1) (lipl32) expressed by adenovirus induced significant protection against a virulent leptospira challenge in gerbils. to avoid the use of the adenovirus vector, we checked for clinical protection against lethal challenge by dna vaccination. a dna vaccine expressing hap1 was designed to ...	2005	15972494
identification of genes of vsh-1, a prophage-like gene transfer agent of brachyspira hyodysenteriae.	vsh-1 is a mitomycin c-inducible prophage of the anaerobic spirochete brachyspira hyodysenteriae. purified vsh-1 virions are noninfectious, contain random 7.5-kb fragments of the bacterial genome, and mediate generalized transduction of b. hyodysenteriae cells. in order to identify and sequence genes of this novel gene transfer agent (gta), proteins associated either with vsh-1 capsids or with tails were purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the n-terminal amino ...	2005	16109929
lrua and lrub, novel lipoproteins of pathogenic leptospira interrogans associated with equine recurrent uveitis.	recurrent uveitis as a sequela to leptospira infection is the most common infectious cause of blindness and impaired vision of horses worldwide. leptospiral proteins expressed during prolonged survival in the eyes of horses with lesions of chronic uveitis were identified by screening a phage library of leptospira interrogans dna fragments with eye fluids from uveitic horses. inserts of reactive phages encoded several known leptospiral proteins and two novel putative lipoproteins, lrua and lrub. ...	2005	16239521
enzyme patterns in the study of leptospira.	an analysis of intracellular and extracellular leptospiral enzymes was made by use of starch-gel electrophoresis with natural and synthetic substrates. of 37 serotypes examined for extracellular exterase, all had activity of varying mobility and degree. all extracellular preparations were negative for catalase, phosphatase, and naphthylamidase. intracellularly, five serotypes were examined, including leptospira biflexa patoc i, l. biflexa waz, l. canicola moulton, l. icterohaemorrhagiae rga, and ...	1967	16349726
the scc spirochetal coiled-coil protein forms helix-like filaments and binds to nucleic acids generating nucleoprotein structures.	the analysis of the genome of leptospira spp., a group of bacteria of the phylum of spirochetes with several unique evolutionary and morphological features, has allowed the identification of a gene encoding a coiled-coil protein, called scc, which is completely unrelated to any other eukaryotic or prokaryotic protein. since coiled-coil proteins are often key elements of the cytoskeleton, we analyzed the protein scc, which is a 24-kda protein composed of a n-terminal coiled-coil domain, a proline ...	2006	16385037
mage: a microbial genome annotation system supported by synteny results.	magnifying genomes (mage) is a microbial genome annotation system based on a relational database containing information on bacterial genomes, as well as a web interface to achieve genome annotation projects. our system allows one to initiate the annotation of a genome at the early stage of the finishing phase. mage's main features are (i) integration of annotation data from bacterial genomes enhanced by a gene coding re-annotation process using accurate gene models, (ii) integration of results o ...	2006	16407324
mutations conferring aminoglycoside and spectinomycin resistance in borrelia burgdorferi.	we have isolated and characterized in vitro mutants of the lyme disease agent borrelia burgdorferi that are resistant to spectinomycin, kanamycin, gentamicin, or streptomycin, antibiotics that target the small subunit of the ribosome. 16s rrna mutations a1185g and c1186u, homologous to escherichia coli nucleotides a1191 and c1192, conferred >2,200-fold and 1,300-fold resistance to spectinomycin, respectively. a 16s rrna a1402g mutation, homologous to e. coli a1408, conferred >90-fold resistance ...	2006	16436695
leptospirosis in the tropics and in travelers.	leptospirosis, caused by spirochetes of the genus leptospira, has increasingly been recognized to affect travelers and residents in tropical settings. a zoonotic disease, leptospirosis is transmitted to humans through environmental surface waters contaminated by the urine of chronically infected mammals. outcome of infection varies, ranging from acute febrile illness (including self-resolving undifferentiated fever) to aseptic meningitis to a fulminant syndrome of jaundice, oliguric renal failur ...	2006	16448601
enhanced diastereoselectivity in beta-mannopyranosylation through the use of sterically minimal propargyl ether protecting groups.	[reaction: see text] 2-o-propargyl ethers are shown to be advantageous in the 4,6-o-benzylidene acetal directed beta-mannosylation reaction. the effect is most pronounced when the o3 protecting group is a bulky silyl ether or a glycosidic bond; however, even with a 3-o-benzyl ether, the use of a 2-o-propargyl ether results in a significant increase in diastereoselectivity. the beneficial effect of the propargyl ether is thought to be a combination of its minimal steric bulk, as determined by a m ...	2006	16599600
lfha, a novel factor h-binding protein of leptospira interrogans.	the early phase of leptospiral infection is characterized by the presence of live organisms in the blood. pathogenic leptospira interrogans is resistant to the alternative pathway of complement mediated-killing, while nonpathogenic members of the genus are not. consistent with that observation, only pathogenic leptospires bound factor h, a host fluid-phase regulator of the alternative complement pathway. ligand affinity blot analyses revealed that pathogenic l. interrogans produces at least two ...	2006	16622202
a newly identified leptospiral adhesin mediates attachment to laminin.	pathogenic leptospires have the ability to survive and disseminate to multiple organs after penetrating the host. several pathogens, including spirochetes, have been shown to express surface proteins that interact with the extracellular matrix (ecm). this adhesin-mediated binding process seems to be a crucial step in the colonization of host tissues. this study examined the interaction of putative leptospiral outer membrane proteins with laminin, collagen type i, collagen type iv, cellular fibro ...	2006	16954400
major role for feob in campylobacter jejuni ferrous iron acquisition, gut colonization, and intracellular survival.	to assess the importance of ferrous iron acquisition in campylobacter physiology and pathogenesis, we disrupted and characterized the fe2+ iron transporter, feob, in campylobacter jejuni nctc 11168, 81-176, and atcc 43431. the feob mutant was significantly affected in its ability to transport 55fe2+. it accumulated half the amount of iron than the wild-type strain during growth in an iron-containing medium. the intracellular iron of the feob mutant was localized in the periplasmic space versus t ...	2006	16988218
identification of potential virulence determinants by himar1 transposition of infectious borrelia burgdorferi b31.	lyme disease borrelia organisms are highly invasive spirochetes that alternate between vertebrate and arthropod hosts and that establish chronic infections and elicit inflammatory reactions in mammals. although progress has been made in the targeted mutagenesis of individual genes in infectious borrelia burgdorferi, the roles of the vast majority of gene products in pathogenesis remain unresolved. in this study, we examined the feasibility of using transposon mutagenesis to identify infectivity- ...	2006	17015459
species-specific identification of leptospiraceae by 16s rrna gene sequencing.	the genus leptospira is classified into 13 named species and 4 genomospecies based upon dna-dna reassociation studies. phenotypic tests are unable to distinguish between species of leptospira, and there is a need for a simplified molecular approach to the identification of leptospires. 16s rrna gene sequences are potentially useful for species identification of leptospira, but there are a large number of sequences of various lengths and quality in the public databases. 16s rrna gene sequences of ...	2006	17021075
application of multilocus variable-number tandem-repeat analysis for molecular typing of the agent of leptospirosis.	leptospirosis is a worldwide-distributed zoonosis, endemic in tropical areas. epidemiologic investigations of leptospirosis still rely on tedious serological identification tests. recently, molecular typing systems based on variable-number tandem-repeat (vntr) analysis have been described and have been used to identify leptospira interrogans strains. although l. interrogans is the most common leptospira species encountered in human infections around the world, other pathogenic species, such as l ...	2006	17088367
in silico and microarray-based genomic approaches to identifying potential vaccine candidates against leptospira interrogans.	currently available vaccines against leptospirosis are of low efficacy, have an unacceptable side-effect profile, do not induce long-term protection, and provide no cross-protection against the different serovars of pathogenic leptospira. the current major focus in leptospirosis research is to discover conserved protective antigens that may elicit longer-term protection against a broad range of leptospira. there is a need to screen vaccine candidate genes in the genome of leptospira interrogans.	2006	17109759
a genomic island of the pathogen leptospira interrogans serovar lai can excise from its chromosome.	an examination of the two leptospira interrogans genomes sequenced so far reveals few genetic differences, including an extra dna region, 54 kb in length, in l. interrogans serovar lai. this locus contains 103 predicted coding sequences that are absent from the genome of l. interrogans serovar copenhageni, of which only 20% had significant blastp hits in genbank. by analyzing the l. interrogans serovar lai genome by pulsed-field gel electrophoresis, we also found that this 54-kb dna fragment exi ...	2007	17118975
a genomic island of the pathogen leptospira interrogans serovar lai can excise from its chromosome.	an examination of the two leptospira interrogans genomes sequenced so far reveals few genetic differences, including an extra dna region, 54 kb in length, in l. interrogans serovar lai. this locus contains 103 predicted coding sequences that are absent from the genome of l. interrogans serovar copenhageni, of which only 20% had significant blastp hits in genbank. by analyzing the l. interrogans serovar lai genome by pulsed-field gel electrophoresis, we also found that this 54-kb dna fragment exi ...	2007	17118975
a comprehensive survey on isoleucine biosynthesis pathways in seven epidemic leptospira interrogans reference strains of china.	previous studies have indicated that different species of leptospira synthesize isoleucine via either pyruvate and/or threonine pathways. seven epidemic leptospira interrogans reference strains from china belonging to different serovars, together with three saprophytic strains of leptospira biflexa and leptospira meyeri, were analysed. the isoleucine biosynthesis properties were studied firstly by measuring the key enzymes of the two pathways, citramalate synthase (cima, ce4.1.3.-) and threonine ...	2007	17227461
response of leptospira interrogans to physiologic osmolarity: relevance in signaling the environment-to-host transition.	transmission of pathogenic leptospira between mammalian hosts usually involves dissemination via soil or water contaminated by the urine of carrier animals. the ability of leptospira to adapt to the diverse conditions found inside and outside the host is reflected in its relatively large genome size and high percentage of signal transduction genes. an exception is leptospira borgpetersenii serovar hardjo, which is transmitted by direct contact and appears to have lost genes necessary for surviva ...	2007	17371863
molecular typing of leptospira spp. based on putative o-antigen polymerase gene (wzy), the benefit over 16s rrna gene sequence.	molecular typing of leptospiral strains based on variation within putative o-antigen polymerase gene (wzy) was determined among reference strains and those isolated from patients. using the pcr primers designed from the flanking gene of wzy derived from leptospira interrogans serovar copenhageni, all l. interrogans serovars as well as human and rodent leptospiral isolates from thailand could be amplified. the size of pcr product ranged from 1 to 1.5 kb. the limitation of these primer pairs was t ...	2007	17403048
the shape and dynamics of the leptospiraceae.	most swimming bacteria produce thrust by rotating helical filaments called flagella. typically, the flagella stick out into the external fluid environment; however, in the spirochetes, a unique group that includes some highly pathogenic species of bacteria, the flagella are internalized, being incased in the periplasmic space; i.e., between the outer membrane and the cell wall. this coupling between the periplasmic flagella and the cell wall allows the flagella to serve a skeletal, as well as a ...	2007	17434949
extended haplotypes in the complement factor h (cfh) and cfh-related (cfhr) family of genes protect against age-related macular degeneration: characterization, ethnic distribution and evolutionary implications.	variants in the complement factor h gene (cfh) are associated with age-related macular degeneration (amd). cfh and five cfh-related genes (cfhr1-5) lie within the regulators of complement activation (rca) locus on chromosome 1q32. aims and methods. in this study, the structural and evolutionary relationships between these genes and amd was refined using a combined genetic, molecular and immunohistochemical approach.	2006	17438673
use of immunoblotting as an alternative method for serogrouping leptospira.	leptospirosis is a worldwide zoonotic disease caused by a spirochaete bacterium, leptospira. serological detection of this micro-organism basically relies on a conventional microscopic agglutination test (mat), which has some limitations and disadvantages. in the present study, immunoblotting has been applied as an alternative method for differentiating serogroups and serovars of leptospires. leptospiral whole-cell lysates from a total of 26 serovars were subjected to immunoblotting using rabbit ...	2007	17446278
expression and characterization of an iron-regulated hemin-binding protein, hbpa, from leptospira interrogans serovar lai.	in an earlier study, based on the ferric enterobactin receptor fepa of escherichia coli, we identified and modeled a tonb-dependent outer membrane receptor protein (lb191) from the genome of leptospira interrogans serovar lai. based on in silico analysis, we hypothesized that this protein was an iron-dependent hemin-binding protein. in this study, we provide experimental evidence to prove that this protein, termed hbpa (hemin-binding protein a), is indeed an iron-regulated hemin-binding protein. ...	2007	17576761
analysis of a ferric uptake regulator (fur) mutant of desulfovibrio vulgaris hildenborough.	previous experiments examining the transcriptional profile of the anaerobe desulfovibrio vulgaris demonstrated up-regulation of the fur regulon in response to various environmental stressors. to test the involvement of fur in the growth response and transcriptional regulation of d. vulgaris, a targeted mutagenesis procedure was used for deleting the fur gene. growth of the resulting deltafur mutant (jw707) was not affected by iron availability, but the mutant did exhibit increased sensitivity to ...	2007	17630305
the ompa-like protein loa22 is essential for leptospiral virulence.	pathogenic mechanisms of leptospira interrogans, the causal agent of leptospirosis, remain largely unknown. this is mainly due to the lack of tools for genetic manipulations of pathogenic species. in this study, we characterized a mutant obtained by insertion of the transposon himar1 into a gene encoding a putative lipoprotein, loa22, which has a predicted ompa domain based on sequence identity. the resulting mutant did not express loa22 and was attenuated in virulence in the guinea pig and hams ...	2007	17630832
iron-regulated proteins (irps) of leptospira biflexa serovar patoc strain patoc i.	iron deficiency has been shown to induce the expression of siderophores and their receptors, the iron-regulated membrane proteins in a number of bacterial systems. in this study, the response of leptospira biflexa serovar patoc strain patoc i to conditions of iron deprivation was assessed and the expression of siderophores and iron-regulated proteins is reported.	2004	17642703
identification of leptospiral isolates by bacterial restriction endonuclease analysis (brenda).	dna samples from 19 reference serovars belonging to 19 different serogroups of leptospira interrogans and two serovars belonging to leptospira biflexa were examined by bacterial restriction endonuclease analysis using ecor i and hae iii enzymes. all the serovars gave unique restriction patterns that differed from each other. dna from 10 local isolates digested with these enzymes produced patterns which on comparison with the standard patterns produced by reference strains could be identified to ...	2001	17664802
convergent synthesis of a beta-(1-->3)-mannohexaose.	an as yet unknown beta-(1-->3)-mannohexaose has been synthesized by a block route involving the coupling of two trisaccharides. comparison of three closely related attempted mannohexaose syntheses reinforces the influence of subtle matching and/or mismatching interactions on the outcome of convergent oligosaccharide synthesis.	2007	17665957
[evaluation of the transcription of locus rfb for the biosynthesis of lps in leptospira interrogans subtype hardjoprajitno].	plasmid pgl4w15-96 was constructed from the pgl4w74 vector without promoter for kanamycin and a sequence of 480pb containing the supposed j15 promoter with the objective of confirming the role of j15 sequence as a promoter for leptospira, which restored the transcription of the gene of resistance to kanamycin in escherichia coli and leptospira biflexa, corroborating this way the function of the insertion as a promoter for both organisms.	2005	17966475
conjugative transfer between escherichia coli and leptospira spp. as a new genetic tool.	our understanding of leptospiral pathogenesis, which remains poorly understood, depends on reliable genetic tools for functional analysis of genes in pathogenic strains. in this study, we report the first demonstration of conjugation between escherichia coli and leptospira spp. by using rp4 derivative conjugative plasmids. the dna transfer described here was due to authentic conjugation, as shown by the requirement for cell-to-cell contact and the resistance of dna transfers to the addition of d ...	2008	17993560
conjugative transfer between escherichia coli and leptospira spp. as a new genetic tool.	our understanding of leptospiral pathogenesis, which remains poorly understood, depends on reliable genetic tools for functional analysis of genes in pathogenic strains. in this study, we report the first demonstration of conjugation between escherichia coli and leptospira spp. by using rp4 derivative conjugative plasmids. the dna transfer described here was due to authentic conjugation, as shown by the requirement for cell-to-cell contact and the resistance of dna transfers to the addition of d ...	2008	17993560
leptospirosis vaccines.	abstract: leptospirosis is a serious infection disease caused by pathogenic strains of the leptospira spirochetes, which affects not only humans but also animals. it has long been expected to find an effective vaccine to prevent leptospirosis through immunization of high risk humans or animals. although some leptospirosis vaccines have been obtained, the vaccination is relatively unsuccessful in clinical application despite decades of research and millions of dollars spent. in this review, the r ...	2007	18072968
early diagnosis of leptospirosis by immunoglobulin m immunoblot testing.	there is an urgent need for the development of serodiagnostic approaches with improved sensitivity for patients with acute leptospirosis. immunoblots were performed on 188 sera collected from 74 patients with laboratory-confirmed early leptospiral infection to detect immunoglobulin m (igm) antibodies to antigens pooled from 10 leptospiral strains prevalent in thailand. sera from patients with other febrile diseases served as controls. igm reactivity to seven distinct antigens, with apparent mole ...	2008	18184827
the tryptophan pathway genes of the sargasso sea metagenome: new operon structures and the prevalence of non-operon organization.	the enormous database of microbial dna generated from the sargasso sea metagenome provides a unique opportunity to locate genes participating in different biosynthetic pathways and to attempt to understand the relationship and evolution of those genes. in this article, an analysis of the sargasso sea metagenome is made with respect to the seven genes of the tryptophan pathway.	2008	18221558
heme rescues a two-component system leptospira biflexa mutant.	heme is typically a major iron source for bacteria, but little is known about how bacteria of the leptospira genus, composed of both saprophytic and pathogenic species, access heme.	2008	18234085
genome sequence of the saprophyte leptospira biflexa provides insights into the evolution of leptospira and the pathogenesis of leptospirosis.	leptospira biflexa is a free-living saprophytic spirochete present in aquatic environments. we determined the genome sequence of l. biflexa, making it the first saprophytic leptospira to be sequenced. the l. biflexa genome has 3,590 protein-coding genes distributed across three circular replicons: the major 3,604 chromosome, a smaller 278-kb replicon that also carries essential genes, and a third 74-kb replicon. comparative sequence analysis provides evidence that l. biflexa is an excellent mode ...	2008	18270594
lipl32 is an extracellular matrix-interacting protein of leptospira spp. and pseudoalteromonas tunicata.	lipl32 is the major outer membrane protein in pathogenic leptospira. it is highly conserved throughout pathogenic species and is expressed in vivo during human infection. while these data suggest a role in pathogenesis, a function for lipl32 has not been defined. outer membrane proteins of gram-negative bacteria are the first line of molecular interaction with the host, and many have been shown to bind host extracellular matrix (ecm). a search for leptospiral ecm-interacting proteins identified ...	2008	18285490
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.	2008	18357340
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 ...	2008	18362131
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 ...	2008	18391007
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 ...	2008	18400972
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 ...	2008	18445272
genomes of model organisms: know thy tools.		2008	18474084
borrelia burgdorferi vlse antigenic variation is not mediated by reca.	reca is a key protein linking genetic recombination to dna replication and repair in bacteria. previous functional characterization of borrelia burgdorferi reca indicated that the protein is mainly involved in genetic recombination rather than dna repair. genetic recombination may play a role in b. burgdorferi persistence by generation of antigenic variation. we report here the isolation of a reca null mutant in an infectious b. burgdorferi strain. comparison of the in vitro growth characteristi ...	2008	18606826
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 ...	2008	18648538
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 ...	2008	18692158
inducible siphoviruses in superficial and deep tissue isolates of propionibacterium acnes.	propionibacterium acnes is a commensal of human skin but is also known to be involved in certain diseases, such as acne vulgaris and infections of orthopaedic implants. treatment of these conditions is complicated by increased resistance to antibiotics and/or biofilm formation of p. acnes bacteria. p. acnes can be infected by bacteriophages, but until recently little has been known about these viruses. the aim of this study was to identify and characterize inducible phages from p. acnes on a gen ...	2008	18702830
genetic manipulation of leptospira biflexa.	the genus leptospira belongs to the order spirochaetales and is composed of both saprophytic and pathogenic members, such as leptospira biflexa and l. interrogans, respectively. a major factor contributing to our ignorance of spirochetal biology has been the lack of methods available for genetic analysis of these organisms. in recent years, an e. coli-l. biflexa shuttle vector has been constructed and a system for targeted mutagenesis and random transposon mutagenesis of the saprophyte l. biflex ...	2007	18770609