We present evidence showing that rpoS (katF) is a regulator of katG gene transcription in an oxyR-independent manner. Mutation of the rpoS gene in several different Escherichia coli strains caused a significant reduction in catalase HPI activity. In rpoS-delta oxyR double mutants, the level of HPI was considerably lower compared to the delta oxyR parent strain, and was restored when transformed with an rpoS+ plasmid. Overproduction of HPI in oxyR- suppressor strains was greatly diminished after inactivation of the rpoS gene and was accompanied by a substantial increase in sensitivity to menadione. Beta-galactosidase expression from a katG::lacZ promoter was lower in rpoS strains compared to rpoS+ isogenic parents. Several delta oxyR strains had detectable levels of katG transcription that was significantly diminished after rpoS gene inactivation.

No abstract

While hepatitis E is a growing health concern in Europe, epidemiological data on hepatitis E virus (HEV) in Estonia are scarce. Along with imported HEV infections, autochthonous cases are reported from European countries. Both domestic and wild animals can be a source of human cases of this zoonosis. Here, we investigated the presence of anti-HEV antibodies and HEV RNA in domestic pigs and wild boars, as well as in pig farm workers and hunters in Estonia. Anti-HEV antibodies were detected in 234/380 (61.6 %) of sera from domestic pigs and in all investigated herds, and in 81/471 (17.2 %) of meat juice samples from wild boars. HEV RNA was detected by real-time PCR in 103/449 (22.9 %) of fecal samples from younger domestic pigs and 13/81 (16.0 %) of anti-HEV-positive wild boar samples. Analysis of sera from 67 pig farm workers and 144 hunters revealed the presence of HEV-specific IgG in 13.4 and 4.2 % of the samples, respectively. No HEV RNA was detected in the human serum samples. Phylogenetic analyses of HEV sequences from domestic pigs and wild boars, based on a 245 bp fragment from the open reading frame 2 showed that all of them belonged to genotype 3. The present study demonstrates the presence of HEV in Estonian domestic pig and wild boar populations, as well as in humans who have direct regular contact with these animals. Our results suggest that HEV infections are present in Estonia and require attention.

We reported previously the antiviral activity named HRF (HIV-1 Resistance Factor) secreted by HIV-1 resistant cells. This work describes the identification of HRF from cell culture supernatant of HRF producing cells (HRF(+) cells). Employing the proteomics and cell based activity assay we recovered ten peptides sharing 80-93% sequence homology with other eukaryotic DING proteins; discrete amino acid characteristics found in our material suggested that HRF is a new member of DING proteins family and consequently we designated it as X-DING-CD4 (extracellular DING from CD4 + T cells). The presence of X-DING-CD4 in the extracellular compartment of HRF(+) but not control HRF(-) cells was confirmed by specific anti-X-DING-CD4 antibody. Similar as the unfractionated HRF(+) cell culture supernatant, the purified X-DING-CD4 blocked transcription of HIV-1 LTR promoted expression of luciferase gene and replication of HIV-1 in MAGI cells. The X-DING-CD4 -mediated antiviral activity in MAGI cells could be blocked by specific antibody.