Total soluble protein profiles of Beauveria bassiana and their relationship with virulence against Helicoverpa armigera

Intracellular total soluble proteins of Beauveria bassiana are believed to play an important role in virulence against insect hosts. Thirty B. bassiana isolates collected from different geographical regions and host ranges were characterised by total soluble proteins present in cells, using the SDS–PAGE technique to differentiate the isolates based on virulence and host insect origin. In vitro analysis of total soluble protein profiles of 30 isolates was studied to understand the relationship of isolates with their host of origin and virulence against Helicoverpa armigera. There was a positive relationship between virulence and host origin. All the non-virulent isolates are grouped together. Similarly, highly virulent isolates against H. armigera were grouped together. The relationship between total soluble proteins and pathogenicity was positively correlated. Thirty isolates shared only 22% similarity in their protein profiles.     

Proteogenomic analysis of Mycobacterium tuberculosis by high resolution mass spectrometry

The genome sequencing of H37Rv strain of Mycobacterium tuberculosis was completed in 1998 followed by the whole genome sequencing of a clinical isolate, CDC1551 in 2002. Since then, the genomic sequences of a number of other strains have become available making it one of the better studied pathogenic bacterial species at the genomic level. However, annotation of its genome remains challenging because of high GC content and dissimilarity to other model prokaryotes. To this end, we carried out an in-depth proteogenomic analysis of the M. tuberculosis H37Rv strain using Fourier transform mass spectrometry with high resolution at both MS and tandem MS levels. In all, we identified 3176 proteins from Mycobacterium tuberculosis representing ~80% of its total predicted gene count. In addition to protein database search, we carried out a genome database search, which led to identification of ~250 novel peptides. Based on these novel genome search-specific peptides, we discovered 41 novel protein coding genes in the H37Rv genome. Using peptide evidence and alternative gene prediction tools, we also corrected 79 gene models. Finally, mass spectrometric data from N terminus-derived peptides confirmed 727 existing annotations for translational start sites while correcting those for 33 proteins. We report creation of a high confidence set of protein coding regions in Mycobacterium tuberculosis genome obtained by high resolution tandem mass-spectrometry at both precursor and fragment detection steps for the first time. This proteogenomic approach should be generally applicable to other organisms whose genomes have already been sequenced for obtaining a more accurate catalogue of protein-coding genes.     

Nitrate reduction by Desulfovibrio desulfuricans: a periplasmic nitrate reductase system that lacks NapB, but includes a unique tetraheme c-type cytochrome, NapM

Many sulphate reducing bacteria can also reduce nitrite, but relatively few isolates are known to reduce nitrate. Although nitrate reductase genes are absent from Desulfovibrio vulgaris strain Hildenborough, for which the complete genome sequence has been reported, a single subunit periplasmic nitrate reductase, NapA, was purified from Desulfovibrio desulfuricans strain 27774, and the structural gene was cloned and sequenced. Chromosome walking methods have now been used to determine the complete sequence of the nap gene cluster from this organism. The data confirm the absence of a napB homologue, but reveal a novel six-gene organisation, napC-napM-napA-napD-napG-napH. The NapC polypeptide is more similar to the NrfH subgroup of tetraheme cytochromes than to NapC from other bacteria. NapM is predicted to be a tetra-heme c-type cytochrome with similarity to the small tetraheme cytochromes from Shewanella oneidensis. The operon is located close to a gene encoding a lysyl-tRNA synthetase that is also found in D. vulgaris. We suggest that electrons might be transferred to NapA either from menaquinol via NapC, or from other electron donors such as formate or hydrogen via the small tetraheme cytochrome, NapM. We also suggest that, despite the absence of a twin-arginine targeting sequence, NapG might be located in the periplasm where it would provide an alternative direct electron donor to NapA.     

Myosin-II reorganization during mitosis is controlled temporally by its dephosphorylation and spatially by Mid1 in fission yeast

Cytokinesis in many eukaryotes requires an actomyosin contractile ring. Here, we show that in fission yeast the myosin-II heavy chain Myo2 initially accumulates at the division site via its COOH-terminal 134 amino acids independently of F-actin. The COOH-terminal region can access to the division site at early G2, whereas intact Myo2 does so at early mitosis. Ser1444 in the Myo2 COOH-terminal region is a phosphorylation site that is dephosphorylated during early mitosis. Myo2 S1444A prematurely accumulates at the future division site and promotes formation of an F-actin ring even during interphase. The accumulation of Myo2 requires the anillin homologue Mid1 that functions in proper ring placement. Myo2 interacts with Mid1 in cell lysates, and this interaction is inhibited by an S1444D mutation in Myo2. Our results suggest that dephosphorylation of Myo2 liberates the COOH-terminal region from an intramolecular inhibition. Subsequently, dephosphorylated Myo2 is anchored by Mid1 at the medial cortex and promotes the ring assembly in cooperation with F-actin.     

Expression of COX-1 and COX-2 in the endometrium of cyclic,pregnant and in a model of pseudopregnant rats and their regulation by sex steroids

Background  

Cyclooxygenases (COXs) are the rate limiting enzymes in the process of prostaglandins (PGs) synthesis, which are critical regulators of a number of reproductive processes, including ovulation, implantation, decidualization and parturition. The aim of the present study was to investigate the expression and regulation of COX-1 and COX-2 and levels of prostaglandins during rat pregnancy, in a model of pseudopregnancy and estrous cycle.     

Unique and conserved features of floral evocation in legumes

Legumes, with their unique ability to fix atmospheric nitrogen, play a vital role in ensuring future food security and mitigating the effects of climate change because they use less fossil energy and produce less greenhouse gases compared with N-fertilized systems. Grain legumes are second only to cereal crops as a source of human and animal food, and they contribute approximately one third of the protein consumed by the human population. The productivity of seed crops, such as grain legumes, is dependent on flowering. Despite the genetic variation and importance of flowering in legume production, studies of the molecular pathways that control flowering in legumes are limited.Recent advances in genomics have revealed that legume flowering pathways are divergent from those of such model species as Arabidopsis thaliana. Here, we discuss the current understanding of flowering time regulation in legumes and highlight the unique and conserved features of floral evocation in legumes.     

Membrane protein crystallization in lipidic mesophases with tailored bilayers

Monoacylglycerols have been used as bilayered hosts for growing crystals of membrane proteins. To date, the lipids used have had chains 16 and 18 carbon atoms long. We hypothesized that a shorter-chained lipid producing a thinner bilayer would facilitate the so-called in meso crystallization process. A 14 carbon monoacylglycerol was chosen as the lipid with which to test the proposal. To be compatible with the in meso method, a cis olefinic bond was placed in its acyl chain at a location arrived at by rational design. The target lipid was synthesized and was shown to form the requisite mesophase at room temperature. In support of the hypothesis, it produced crystals of bacteriorhodopsin and the outer membrane transporter, BtuB. The latter is the first beta barrel protein to be crystallized by the in meso method. Protein stability in the short-chain lipid and how this relates to crystallogenesis are discussed.