Genetic differences among the LPS biosynthetic loci of serovars of Leptospira interrogans and Leptospira borgpetersenii

Abstract

The gene organization in the lipopolysaccharide biosynthetic (rfb) locus was analyzed in seven Leptospira interrogans serovars within serogroup Icterohemorrhagiae, seven non-Icterohemorrhagiae serovars and one Leptospira borgpetersenii serovar. Two groups of loci were delineated based on DNA hybridization and sequence analysis. Group 1 contained the two Hardjo subtypes, Hardjoprajitno and Hardjobovis. Group 2 (containing Copenhageni, Pomona, Naam, Mwogolo, Smithi, Lai, Canicola, Autumnalis, Pyrogenes, Australis and Icterohemorrhagiae) differed from Group 1 in its organization upstream of orf11, where five ORFs (32, 33, 34, 35, 37) were identified that were not contained in the Group 1 loci. These ORFs encoded a putative epimerase (orf32), a glycosyltransferase (orf33), two integral membrane proteins (orfs 34 and 35), and a galactosyltransferase (orf37). Serovars Australis, Pomona and Autumnalis did not contain orf37. Serovar Bataviae was excluded from the grouping because of its unique genetic organization upstream of orf13. In the Group 2 loci, comparison of the genetic layout at the 5' end revealed differences which included mutations disrupting reading frames in either or both orf34 and orf35 and apparent allelic differences between orf33 homologs that may be sufficient to account for the genetic basis of serovar identity.

Characterization of Three Novel Adhesins of Leptospira interrogans

“…General features of Lsa26, Lsa23, and Lsa36 are summarized in Table 1. The CDSs have been identified by proteomics in L. interrogans serovar Copenhageni strain FIOCRUZ L1-130, but only in the case of LIC11009 could the number of copies per cell be determined (2,566), and LIC11360 and LIC11975 are probably expressed in amounts below the detection limit of the method. 38 Expression, purification, and identification of recombinant proteins.…”

“…1 Structural heterogeneity in the carbohydrate component of leptospiral lipopolysaccharides results in serovar diversity; more than 250 serovars have been described. 2 Many serovars are adapted for specific mammalian reservoir hosts, which harbor the organisms in their renal tubules and shed live leptospires in their urine. Humans are accidental hosts who become infected through contact with wild or domestic animals or exposure to contaminated soil or water.…”

Application of Multilocus Variable-Number Tandem-Repeat Analysis for Molecular Typing of the Agent of Leptospirosis

“…VNTR-10 is located within the rfb locus, which encodes proteins involved in lipopolysaccharide O-antigen biosynthesis. The rfb locus has a different genetic organization in L. interrogans and L. borgpetersenii serovars (5,6,13). However, the gene organization around VNTR-10 seems to be conserved, irrespective of the serovar and the species considered.…”

Changes in Lipopolysaccharide O Antigen Distinguish Acute versus Chronic Leptospira interrogans Infections

“…Electrophoretic profiles of pathogenic strains of Leptospira differ between species and typically comprise two or three major bands (7,40). The rfb locus of Leptospira has been extensively characterized (5,6,9,10,18,25). Aside from being a protective antigen against homologous challenge, LPS Oag forms the basis for the reference diagnostic assay for leptospirosis, the microscopic agglutination test, in which live leptospires representing a panel of serovars undergo reaction with patient serum samples to detect agglutinating antibodies.…”