I. E. Vishnyakov, S. N. Borchsenius, Yu. I. Basovskii, S. A. Levitskii, V. N. Lazarev, E. S. Snigirevskaya, Ya. Yu. Komissarchik[show abstract] [hide abstract]
ABSTRACT: The localization of FtsZ protein in M. hominis cells was studied by immunoelectron microscopy with polyclonal antibodies to this protein. Cell polymorphism typical for mycoplasmas was seen on electron microscopic pictures. Among the diversity of cell shapes, we distinguished dumbbell-shaped dividing cells and cells connected with each other by membrane tubules (former constrictions). The label was predominantly observed in the constriction area of dividing M. hominis cells and on thin membrane tubules. A septum and the gold labeling of this structure have not been described before in mycoplasma cells. For the first time, in some rounded and oval cells, colloidal gold particles labeled the entire plasma membrane, probably marking a submembranous contractile ring (Z ring). These observations confirm the implication of FtsZ protein in M. hominis cytokinesis. In some cells, the spiral-like distribution of gold particles was observed. Most likely, FtsZ protofilaments in M. hominis cells form spiral structures similar to Z spirals in Bacillus subtilis and Escherichia coli. Their presence in mycoplasma cells may be considered to be an important argument in favor of Z ring assembly through the reorganization of Z spirals. FtsZ as a bacterial cytoskeleton protein binding with membrane directly or through intermediates may be engaged in maintenance of M. hominis cell shape.Cell and Tissue Biology 04/2012; 3(3):254-262.
V N Lazarev, S A Levitskii, Y I Basovskii, M M Chukin, T A Akopian, V V Vereshchagin, E S Kostrjukova, G Y Kovaleva, M D Kazanov, D B Malko, [......], N V Sernova, M S Gelfand, I A Demina, M V Serebryakova, M A Galyamina, N N Vtyurin, S I Rogov, D G Alexeev, V G Ladygina, V M Govorun[show abstract] [hide abstract]
ABSTRACT: We present the complete genome sequence and proteogenomic map for Acholeplasma laidlawii PG-8A (class Mollicutes, order Acholeplasmatales, family Acholeplasmataceae). The genome of A. laidlawii is represented by a single 1,496,992-bp circular chromosome with an average G+C content of 31 mol%. This is the longest genome among the Mollicutes with a known nucleotide sequence. It contains genes of polymerase type I, SOS response, and signal transduction systems, as well as RNA regulatory elements, riboswitches, and T boxes. This demonstrates a significant capability for the regulation of gene expression and mutagenic response to stress. Acholeplasma laidlawii and phytoplasmas are the only Mollicutes known to use the universal genetic code, in which UGA is a stop codon. Within the Mollicutes group, only the sterol-nonrequiring Acholeplasma has the capacity to synthesize saturated fatty acids de novo. Proteomic data were used in the primary annotation of the genome, validating expression of many predicted proteins. We also detected posttranslational modifications of A. laidlawii proteins: phosphorylation and acylation. Seventy-four candidate phosphorylated proteins were found: 16 candidates are proteins unique to A. laidlawii, and 11 of them are surface-anchored or integral membrane proteins, which implies the presence of active signaling pathways. Among 20 acylated proteins, 14 contained palmitic chains, and six contained stearic chains. No residue of linoleic or oleic acid was observed. Acylated proteins were components of mainly sugar and inorganic ion transport systems and were surface-anchored proteins with unknown functions.Journal of bacteriology 07/2011; 193(18):4943-53. · 3.94 Impact Factor
Article: Localization of C. trachomatis Inc proteins in expression of their genes in HeLa cell culture.[show abstract] [hide abstract]
ABSTRACT: Co-localization of Chlamydia trachomatis incorporation membrane proteins with cell organelles was studied in HeLa cell culture after transfection by expressing vectors carrying incA, incB, incC, incD, incE, incF, incG genes, respectively, fused with the marker green fluorescent protein (EGFP) gene. The prokaryotic proteins were co-located with compartments of the secretory pathway of the eukaryotic cell in the course of biogenesis.Bulletin of Experimental Biology and Medicine 09/2008; 146(2):237-42. · 0.27 Impact Factor
Article: Hydrophobic domains determine localization of IncC and IncG full-length proteins of C. trachomatis during their expression in cultured HeLa cells.[show abstract] [hide abstract]
ABSTRACT: Plasmid vectors encoding hydrophilic (IncB, IncC, IncE, IncG) and hydrophobic (IncC, IncG) domains of C. trachomatis incorporation membrane proteins and reporter green fluorescing proteins were constructed. After transfection of HeLa cells with these plasmid constructs, localization of the complex proteins was determined by laser confocal microscopy. Tropism of hydrophobic domains to compartments constituting the exocytotic pathway in the cell was demonstrated. Location of signal/sorting sequences responsible for specific localization was determined.Bulletin of Experimental Biology and Medicine 05/2008; 145(4):425-9. · 0.27 Impact Factor