Mu dI1(Ap lac) mutagenesis of Yersinia pestis plasmid pFra and identification of temperature-regulated loci associated with virulence.

The F1 capsule of Yersinia pestis, encoded by the 100 kb plasmid pFra, is often assumed to be essential for full virulence of Y. pestis. However, virulent strains of Y.

Complete DNA sequence of Yersinia enterocolitica serotype 0:8 low-calcium-response plasmid reveals a new virulence plasmid-associated replicon.

The complete nucleotide sequence and organization of the Yersinia enterocolitica serotype 0:8 low-calcium-response (LCR) plasmid, pYVe8081, were determined. The 67,720-bp plasmid encoded all the genes known to be part of the LCR stimulon except for ylpA. Eight of 13 intact open reading frames of unknown function identified in pYVe8081 had homologues in Yersinia pestis plasmid pCD1 or in Y.

Short report: phylogenetically distinct hepatitis E viruses in Pakistan.

Hepatitis E, which is enterically transmitted, is the most common cause of acute hepatitis in much of Asia. Phylogenetic analysis of several isolates of hepatitis E virus (HEV) from Asia suggests that transmission of this virus is geographically restricted. In Sarghoda, Pakistan, HEV Sar-55 was isolated from a 1987 outbreak.

Genetic characterization of a Tn5-disrupted glycosyltransferase gene homolog in Brucella abortus and its effect on lipopolysaccharide composition and virulence.

We constructed a rough mutant of Brucella abortus 2308 by transposon (Tn5) mutagenesis. Neither whole cells nor extracted lipopolysaccharide (LPS) from this mutant, designated RA1, reacted with a Brucella O-side-chain-specific monoclonal antibody (MAb), Bru-38, indicating the absence of O-side-chain synthesis. Compositional analyses of LPS from strain RA1 showed reduced levels of quinovosamine and mannose relative to the levels in the parental, wild-type strain, 2308.

Hepatitis E virus: complete genome sequence and phylogenetic analysis of a Nepali isolate.

The complete nucleotide sequence of the Nepali strain TK15/92 of hepatitis E (HEV) was determined. It showed the highest sequence homology with the Burmese B1 strain, but closer evolutionary relatedness to the Indian strains. Difficulties in reverse-transcribing and amplifying the hypervariable region in ORF1 suggested that strong secondary structures might be intrinsically responsible for the high mutational rate observed in this region of the HEV genome.