Leptospira biflexa
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA20165 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| Other | ||||
| SRR14134769.fastq.gz | Fastqsanger.gz | |||
| SRR14134770.fastq.gz | Fastqsanger.gz | |||
| SRR14134771.fastq.gz | Fastqsanger.gz | |||
| SRR14134772.fastq.gz | Fastqsanger.gz |
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Project description:BackgroundHeme 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.ResultsIn this study, we analysed a two-component system of the saprophyte Leptospira biflexa. In vitro phosphorylation and site-directed mutagenesis assays showed that Hklep is a histidine kinase which, after autophosphorylation of a conserved histidine, transfers the phosphate to an essential aspartate of the response regulator Rrlep. Hklep/Rrlep two-component system mutants were generated in L. biflexa. The mutants could only grow in medium supplemented with hemin or delta-aminolevulinic acid (ALA). In the pathogen L. interrogans, the hklep and rrlep orthologous genes are located between hemE and hemL genes, which encode proteins involved in heme biosynthesis. The L. biflexa hklep mutant could be complemented with a replicative plasmid harbouring the L. interrogans orthologous gene, suggesting that these two-component systems are functionally similar. By real-time quantitative reverse transcription-PCR, we also observed that this two-component system might influence the expression of heme biosynthetic genes.ConclusionThese findings demonstrate that the Hklep/Rrlep regulatory system is critical for the in vitro growth of L. biflexa, and suggest that this two-component system is involved in a complex mechanism that regulates the heme biosynthetic pathway.
| S-EPMC2266917 | biostudies-literature
Project description:The saprophyte Leptospira biflexa is an excellent model for studying the physiology of the medically important Leptospira genus, the pathogenic members of which are more recalcitrant to genetic manipulation and have significantly slower in vitro growth. However, relatively little is known regarding the proteome of L. biflexa, limiting its utility as a model for some studies. Therefore, we have generated a proteomic map of both soluble and membrane-associated proteins of L. biflexa during exponential growth and in stationary phase. Using these data, we identified abundantly produced proteins in each cellular fraction and quantified the transcript levels from a subset of these genes using quantitative reverse transcription-PCR (RT-PCR). These proteins should prove useful as cellular markers and as controls for gene expression studies. We also observed a significant number of L. biflexa membrane-associated proteins with multiple isoforms, each having unique isoelectric focusing points. L. biflexa cell lysates were examined for several posttranslational modifications suggested by the protein patterns. Methylation and acetylation of lysine residues were predominately observed in the proteins of the membrane-associated fraction, while phosphorylation was detected mainly among soluble proteins. These three posttranslational modification systems appear to be conserved between the free-living species L. biflexa and the pathogenic species Leptospira interrogans, suggesting an important physiological advantage despite the varied life cycles of the different species.
| S-EPMC4751834 | biostudies-literature
Project description:Properdin (P) is a positive regulatory protein that stabilizes the C3 convertase and C5 convertase of the complement alternative pathway (AP). Several studies have suggested that properdin can bind directly to the surface of certain pathogens regardless of the presence of C3bBb. Saprophytic Leptospira are susceptible to complement-mediated killing, but the interaction of properdin with Leptospira spp. has not been evaluated so far. In this work, we demonstrate that properdin present in normal human serum, purified properdin, as well as properdin oligomers P2, P3, and P4, interact with Leptospira. Properdin can bind directly to the bacterial surface even in the absence of C3b. In line with our previous findings, AP activation was shown to be important for killing non-pathogenic L. biflexa, and properdin plays a key role in this process since this microorganism survives in P-depleted human serum and the addition of purified properdin to P-depleted human serum decreases the number of viable leptospires. A panel of pathogenic L. interrogans recombinant proteins was used to identify putative properdin targets. Lsa30, an outer membrane protein from L. interrogans, binds to unfractionated properdin and to a lesser extent to P2-P4 properdin oligomers. In conclusion, properdin plays an important role in limiting bacterial proliferation of non-pathogenic Leptospira species. Once bound to the leptospiral surface, this positive complement regulatory protein of the AP contributes to the formation of the C3 convertase on the leptospire surface even in the absence of prior addition of C3b.
| S-EPMC7683387 | biostudies-literature
Project description:BackgroundLeptospires lack many of the homologs for oxidative defense present in other bacteria, but do encode homologs of the Bacteriodes aerotolerance (Bat) proteins, which have been proposed to fulfill this function. Bat homologs have been identified in all families of the phylum Spirochaetes, yet a specific function for these proteins has not been experimentally demonstrated.ResultsWe investigated the contribution of the Bat proteins in the model organism Leptospira biflexa for their potential contributions to growth rate, morphology and protection against oxidative challenges. A genetically engineered mutant strain in which all bat ORFs were deleted did not exhibit altered growth rate or morphology, relative to the wild-type strain. Nor could we demonstrate a protective role for the Bat proteins in coping with various oxidative stresses. Further, pre-exposing L. biflexa to sublethal levels of reactive oxygen species did not appear to induce a general oxidative stress response, in contrast to what has been shown in other bacterial species. Differential proteomic analysis of the wild-type and mutant strains detected changes in the abundance of a single protein only - HtpG, which is encoded by the gene immediately downstream of the bat loci.ConclusionThe data presented here do not support a protective role for the Leptospira Bat proteins in directly coping with oxidative stress as previously proposed. L. biflexa is relatively sensitive to reactive oxygen species such as superoxide and H2O2, suggesting that this spirochete lacks a strong, protective defense against oxidative damage despite being a strict aerobe.
| S-EPMC3557215 | biostudies-literature
Project description:Baeyer-Villiger monooxygenases are recognized by their ability and high selectivity as oxidative biocatalysts for the generation of esters or lactones using ketones as starting materials. These enzymes represent valuable tools for biooxidative syntheses since they can catalyze reactions that otherwise involve strong oxidative reagents. In this work, we present a novel enzyme, the Type I Baeyer-Villiger monooxygenase from Leptospira biflexa. This protein is phylogenetically distant from other well-characterized BVMOs. In order to study this new enzyme, we cloned its gene, expressed it in Escherichia coli and characterized the substrate scope of the Baeyer-Villiger monooxygenase from L. biflexa as a whole-cell biocatalyst. For this purpose, we performed the screening of a collection of ketones with variable structures and sizes, namely acyclic ketones, aromatic ketones, cyclic ketones, and fused ketones. As a result, we observed that this biocatalyst readily oxidized linear- and branched- medium-chain ketones, alkyl levulinates and linear ketones with aromatic substituents with excellent regioselectivity. In addition, this enzyme catalyzed the oxidation of 2-substituted cycloketone derivatives but showed an unusual selection against substituents in positions 3 or 4 of the ring.
| S-EPMC5407406 | biostudies-literature
Project description:Leptospira spp. are spirochete bacteria that possess periplasmic flagella (PFs) underneath the outer membrane; each flagellum is attached to each end of the protoplasmic cylinder. PFs of Leptospira have a coiled shape that bends the end of the cell body. However, the molecular mechanism by which multiple flagellar proteins organize to form the distinctively curled PF of Leptospira remains unclear. Here we obtained a slow-motility mutant of L. biflexa MD4-3 by random insertion mutagenesis using a Himar1 transposon. In MD4-3, the gene encoding the flagellar sheath protein, flagellar-coiling protein A (FcpA), which was recently identified in L. interrogans, was inactivated. As with L. interrogans ΔfcpA strains, the L. biflexa ΔfcpA strain lacked a distinct curvature at both ends of the cell body, and its motility was significantly reduced as compared with that of the wild-type strain. PFs isolated from the ΔfcpA strain were straight and were thinner than those isolated from the wild-type strain. Western blot analysis revealed that flagellar proteins FlaA1, FlaA2, FlaB1, and FlaB2 were expressed in the ΔfcpA strain but the flagellar proteins, except for FlaB2 were not incorporated in its PFs. Immunoprecipitation assay using anti-FcpA antiserum demonstrated that FcpA associates with FlaA2 and FlaB1. The association between FcpA and FlaA2 was also verified using pull-down assay. The regions of FlaA2 and FlaB1 interacting with FcpA were determined using a bacterial two-hybrid assay. These results suggest that FcpA together with FlaA2, produces coiling of PF of the Leptospira, and the interaction between the sheath and core filament may be mediated by FcpA and FlaB1.
| S-EPMC5892894 | biostudies-literature
Project description: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 model for the study of Leptospira evolution; we conclude that 2052 genes (61%) represent a progenitor genome that existed before divergence of pathogenic and saprophytic Leptospira species. Comparisons of the L. biflexa genome with two pathogenic Leptospira species reveal several major findings. Nearly one-third of the L. biflexa genes are absent in pathogenic Leptospira. We suggest that once incorporated into the L. biflexa genome, laterally transferred DNA undergoes minimal rearrangement due to physical restrictions imposed by high gene density and limited presence of transposable elements. In contrast, the genomes of pathogenic Leptospira species undergo frequent rearrangements, often involving recombination between insertion sequences. Identification of genes common to the two pathogenic species, L. borgpetersenii and L. interrogans, but absent in L. biflexa, is consistent with a role for these genes in pathogenesis. Differences in environmental sensing capacities of L. biflexa, L. borgpetersenii, and L. interrogans suggest a model which postulates that loss of signal transduction functions in L. borgpetersenii has impaired its survival outside a mammalian host, whereas L. interrogans has retained environmental sensory functions that facilitate disease transmission through water.
| S-EPMC2229662 | biostudies-literature
Project description:Characterization of the role of CsrA in gene regulation in Leptospira biflexa
2022-04-13 | E-MTAB-10396 | biostudies-arrayexpress
Project description:The overall goal of these experiments was to determine how human endothelial cells respond to pathogenic Leptospira interrogans. Leptospira interrogans causes leptospirosis, the most widespread zoonotic infection in the world. A hallmark of leptospirosis is widespread endothelial damage, which in severe cases leads to hemorrhage. In these experiments, we infected two endothelial cell lines with pathogenic Leptospira interrogans serovar Canicola strain Ca12-005, and as controls, with the non-pathogenic Leptospira biflexa serovar Patoc strain Pfra. As additional controls, uninfected cells were also included in the analyses.
2010-07-27 | GSE23173 | GEO
Project description:The overall goal of these experiments was to determine how human endothelial cells respond to pathogenic Leptospira interrogans. Leptospira interrogans causes leptospirosis, the most widespread zoonotic infection in the world. A hallmark of leptospirosis is widespread endothelial damage, which in severe cases leads to hemorrhage. In these experiments, we infected two endothelial cell lines with pathogenic Leptospira interrogans serovar Canicola strain Ca12-005, and as controls, with the non-pathogenic Leptospira biflexa serovar Patoc strain Pfra. As additional controls, uninfected cells were also included in the analyses.
2010-07-27 | GSE23172 | GEO