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Sathish Prasad Poorna Manasa Sailaja Buddhi Preethi Tirunagari Zareena Begum Sivaraman Rajan Sisinthy Shivaji 《Current microbiology》2014,68(2):233-238
The diversity and abundance of culturable bacteria in Kongsfjorden water (15 stations) and sediments (12 stations) were studied. Viable numbers ranged between 105–106 CFU l?1 in water and 102–104 CFU g?1 in the sediments. A total of 291 and 43 bacterial isolates were retrieved from the water (KJF) and sediments (FS), respectively. Based on 16S rRNA gene sequence similarities, the KJF and FS isolates were grouped into 49 and 23 phylotypes, respectively. The KJF and FS phylotypes represented three phyla namely, Actinobacteria, Bacteroidetes, and Proteobacteria. At the genus level, Flavobacterium and Shewanella and at the species level, Pseudoaltermonas arctica and Colwellia psychrerythraea were dominant in the water and sediments, respectively. Most phylotypes were psychrotolerant with upper growth temperature limit of 25–37 °C and tolerated 0.3–2.5 M NaCl and pH values of 5.0–11.0. Majority of the phylotypes produced one or more of the extracellular hydrolytic enzymes amylase, lipase, caseinase, urease, gelatinase, and DNase at 4 and 18 °C, while none were chitinolytic. Few of the FS phylotypes exhibited extracellular activity only at 4 or 18 °C. Nine FS and 21 KJF isolates were pigmented. The predominant cellular fatty acids were unsaturated, branched, and modified fatty acids, which are unique to cold-adapted bacteria. 相似文献
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Sankaranarayanan Rishikesan Youg R. Thaker Ragunathan Priya Shovanlal Gayen Malathy S. S. Manimekalai Cornelia Hunke 《Molecular membrane biology》2013,30(5):400-410
A critical point in the V1 sector and entire V1VO complex is the interaction of stalk subunits G (Vma10p) and E (Vma4p). Previous work, using precipitation assays, has shown that both subunits form a complex. In this work, we have analysed the N-terminal segment of subunit G (G1–59) of the V1VO ATPase from Saccharomyces cerevisiae by using nuclear magnetic resonance (NMR) spectroscopy. Analyses of 1H-15N heteronuclear single quantum coherence (HSQC) spectra of G1–59 in the absence and presence of the N-terminal peptides E1–18 and E18–38 as well as the produced and purified C-terminal segment (E39–233) shows specific interactions only with the peptide fragment E18–38. The binding of this peptide occurs via the residues M1, V2, S3, and K5 as well for V22, S23, K24, A25 and R26 of G1–59. The specific E18–38/G1–59 binding has been confirmed by fluorescence correlation spectroscopy data. The E18–38 peptide has been studied by CD spectroscopy and NMR. The 3D structure of this peptide adopts a stable helix-hinge-helix formation in solution. A model structure of the E18–38/G1–59 complex reveals the orientation of E18–38 relative to G1–59 via salt-bridges of the polar residues and van der Waals forces at the very N-terminus of both segments. 相似文献