The ospA and ospB genes encode the major outer membrane proteins of the Lyme disease spirochaete Borrelia burgdorferi. The deduced translation products from the ospA and ospB genes were: (OspA) 273 amino acids long with a molecular weight of 29,334, and (OspB) 296 amino acids long with a molecular weight of 31,739. The two Osp proteins showed a great degree of sequence similarity indicating a recent evolutionary event. Molecular analysis and sequence comparison of OspA and OspB with other proteins revealed a sequence similarity to the signal peptides of prokaryotic lipoproteins. These are the first sequences from Borrelia and provide interesting data on the evolutionary relationship between spirochaetes and other species as well as providing potential for spirochaete diagnostics and vaccines.

Birds host vector ticks and Borrelia species and vary in effectiveness as reservoirs.

To date no nucleic acid has been found in the purified infectious agent which causes the spongiform encephalopathy known as scrapie. In an attempt to identify a unique scrapie virus-associated messenger RNA in tissues of infected animals, we have synthesized an oligonucleotide probe complementary to the mRNA sequence corresponding to the amino-acid sequence of the prion protein, PrP27-30 (ref. 1). We report here that, with this probe, a complementary DNA clone representing PrP27-30 was obtained from scrapie-infected mouse brain; the DNA sequence of this clone could be translated into a protein that matches exactly the published sequence of PrP27-30. The cDNA clone hybridized to a single 2.4-2.5-kilobase (kb) mRNA from both normal and scrapie-infected brain. Thus, the PrP27-30 mRNA is not uniquely associated with scrapie infectivity, suggesting that PrP27-30 may be a normal component of mouse and hamster brain.

The intracellular pathogen Chlamydia trachomatis possesses a type III secretion (TTS) system believed to deliver a series of effector proteins into the inclusion membrane (Inc-proteins) as well as into the host cytosol with perceived consequences for the pathogenicity of this common venereal pathogen. Recently, small molecules were shown to block the TTS system of Yersinia pseudotuberculosis. Here, we show that one of these compounds, INP0400, inhibits intracellular replication and infectivity of C. trachomatis at micromolar concentrations resulting in small inclusion bodies frequently containing only one or a few reticulate bodies (RBs).

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The Lyme disease spirochaete, Borrelia burgdorferi s.l., is the only Borrelia known to infect both mammals and birds. The main vertebrate reservoirs of B. burgdorferi are thought to be various small and intermediate size mammals, but the importance of birds as a reservoir has not been thoroughly explored. In the Northern and Southern Hemispheres the seabird tick, Ixodes uriae, is prevalent and closely associated with many species of colony-nesting marine birds. Here we report the presence of spirochaetes, demonstrated by immunofluorescent assay, by polymerase chain reaction and in culture, in I. uriae infesting razorbills on an island in the Baltic Sea. This island is free from mammals. The protein profile of the spirochaetes and the sequences of their flagellin and ospA genes are identical to those of the Lyme disease spirochaete, Borrelia burgdorferi s.l., previously isolated from I. ricinus on a nearby island. In biopsies from the foot web of razorbills, B. burgdorferi-specific DNA was detected after amplification by polymerase chain reaction. Our results suggest that birds play an important part in the maintenance of B. burgdorferi and that mammals may not be a prerequisite for its life cycle.