Proteorhodopsin genes in giant viruses

Viruses with large genomes encode numerous proteins that do not directly participate in virus biogenesis but rather modify key functional systems of infected cells. We report that a distinct group of giant viruses infecting unicellular eukaryotes that includes Organic Lake Phycodnaviruses and Phaeocystis globosa virus encode predicted proteorhodopsins that have not been previously detected in viruses. Search of metagenomic sequence data shows that putative viral proteorhodopsins are extremely abundant in marine environments. Phylogenetic analysis suggests that giant viruses acquired proteorhodopsins via horizontal gene transfer from proteorhodopsin-encoding protists although the actual donor(s) could not be presently identified. The pattern of conservation of the predicted functionally important amino acid residues suggests that viral proteorhodopsin homologs function as sensory rhodopsins. We hypothesize that viral rhodopsins modulate light-dependent signaling, in particular phototaxis, in infected protists. This article was reviewed by Igor B. Zhulin and Laksminarayan M. Iyer. For the full reviews, see the Reviewers?? reports section.     

The Use of Chitosan to Reduce the Negative Impact of Chemicals on Bees Based on the Example of Amitraz

Applied Biochemistry and Microbiology - The effect of chitosan on the survival of bees treated with the chemical acaricide amitraz at a 50% lethal dose (LD50) of 10 μg per bee was studied. It...     

The entry of the Picornaviridae virus family in resident macrophages

For viruses, the following mechanisms of penetration into cells are typical: clathrin- or dinaminmediated endocytosis, the formation of caveolae, local lysis of cell membranes, and macropinocytosis. It is accepted that (those nonenveloped viruses in the Picornaviridae family) enter cells mostly through the local lysis of their membranes. The purpose of the present study is to research the mechanisms of penetration into resident macrophages of viruses of the indicated family, including poliovirus, Echol1 and Coxsackie B1 viruses, and Type 71 enterovirus. It has been detected that, at the adhesion sites of the Coxsackie B1 virus and Type 71 enterovirus on a macrophage surface, invaginations of the plasma membranes of cells appear, followed by the consequent formation of endocytoplasmatic vesicles, i.e., caveolae. The penetration of poliovirus into macrophages occurs both through the formation of caveolae and the local lysis of the plasmolemma of cells; during the later terms (after 45 min), macropinocytosis is observed in the viral particles during the first 15 min after the Echol1 virus penetrated the cytoplasm of macrophages through the local lysis of their plasmolemma. Thereafter, the formation of endocytic vacuolae including viral particles was observed in the cytoplasm of infected macrophages. The exit of the Echol1 virus from endocytic vacuoles was performed by the local lysis of cell membrane.     

Immunochemical study of the lipopolysaccharides of Yersinia enterocolitica serovars O5 and O5.27

Y. enterocolitica lipopolysaccharides (LPS), serovars O5 and O5.27, have similar antigenic specificity. The LPS of serovar O5.27 has been shown to contain no factor O27. Residual alpha-L-rhamnose, glycosylated by D-xylulose, has been found to play an important role in the formation of factor O5, common for both serovars.     

Cytochrome P450 52A3: Modelling of 3D Structure and Surface Mutations

Abstract

Earlier W.-H. Schunck et al. [1] have prepared a water soluble enzymatically active fragment of cytochrome P450 52A3 (CYP52A3) which is lack of 66 amino acid residues, existed as a dimer in aqueous solution. Now we propose 3D structure of the fragment, which is based on multiple sequence alignment of the CYP52A3 with its homologues proteins of known 3D structure: CYP101, 102, 107A1 and 108. The structural model have been optimised and used as a prototype for computer simulation of point mutations. These mutations should bring some changes in the surface properties, interfering dimer formation. For this aim the point of 22 hydrophobic amino acid residues have been sequentially replaced with that of charged amino acids (GLU, ASP, ARG and LYS). The scoring of “mutants” was conducted based on the changes of protein surface hydrophobicity and protein-solvent interaction energy. An analysis of the surface hydrophobicity and protein-solvent interactions permit to select most sensitive three sites (171, 352 and particularly 164 amino acid residues). The dimerization of the following “mutant” fragments must be investigated experimentally.