Risk for human tick-borne encephalitis, borrelioses, and double infection in the pre-Ural region of Russia.

We assessed the risk for human tick-borne encephalitis (TBE), ixodid tick-borne borrelioses, and double infection from 1994 to 1998 in Perm, which has among the highest rates of reported cases in Russia. We studied 3,473 unfed adult Ixodes persulcatus ticks collected from vegetation in natural foci and 62,816 ticks removed from humans. TBE virus and Borrelia may coexist in ticks

A Mutant Ahr Allele Protects the Embryonic Kidney from Hydrocarbon-Induced Deficits in Fetal Programming

Background: The use of experimental model systems has expedited the elucidation of pathogenetic mechanisms of renal developmental disease in humans and the identification of genes that orchestrate developmental programming during nephrogenesis

RNase H2 of Saccharomyces cerevisiae is a complex of three proteins

The composition of RNase H2 has been a long-standing problem. Whereas bacterial and archaeal RNases H2 are active as single polypeptides, the Saccharomyces cerevisiae homolog, Rnh2Ap, when expressed in Escherichia coli, fails to produce an active RNase H2. By affinity chromatography purification and identification of polypeptides associated with a tagged S.cerevisiae Rnh2Ap, we obtained a complex of three proteins (Rnh2Ap, Ydr279p and Ylr154p) that together are necessary and sufficient for RNase H2 activity. Deletion of the gene encoding any one of the proteins or mutations in the catalytic site in Rnh2A led to loss of RNase H2 activity. Even when S.cerevisiae RNase H2 is catalytically compromised, it still exhibits a preference for cleavage of the phosphodiester bond on the 5′ side of a ribonucleotide–deoxyribonucleotide sequence in substrates mimicking RNA-primed Okazaki fragments or a single ribonucleotide embedded in a duplex DNA. Interestingly, Ydr279p and Ylr154p have homologous proteins only in closely related species. The multisubunit nature of S.cerevisiae RNase H2 may be important both for structural purposes and to provide a means of interacting with other proteins involved in DNA replication/repair and transcription