@article {8356, title = {Lunatimonas lonarensis gen. nov., sp. nov., a haloalkaline bacterium of the family Cyclobacteriaceae with nitrate reducing activity [Next Gen Genomics Facility]}, journal = {Syst Appl Microbiol}, volume = {37}, year = {2014}, month = {2014 Feb}, pages = {10-6}, abstract = {

Novel pinkish-orange pigmented, Gram-negative staining, half-moon shaped, non-motile, strictly aerobic strains designated AK24(T) and AK26 were isolated from water and sediment samples of Lonar Lake, Buldhana district, Maharahstra, India. Both strains were positive for oxidase, catalase and β-galactosidase activities. The predominant fatty acids were iso-C15:0 (41.5\%), anteiso-C15:0 (9.7\%), iso-C17:0 3OH (9.6\%), iso-C17:1 ω9c (10.2\%) and C16:1 ω7c/C16:1 ω6c/iso-C15:0 2OH (summed feature 3) (14.4\%). The strains contained MK-7 as the major respiratory quinone, and phosphatidylethanolamine and five unidentified lipids as the polar lipids. Blast analysis of the 16S rRNA gene sequence of strain AK24(T) showed that it was closely related to Aquiflexum balticum, with a pair-wise sequence similarity of 91.6\%, as well as to Fontibacter ferrireducens, Belliella baltica and Indibacter alkaliphilus (91.3, 91.2 and 91.2\% pair-wise sequence similarity, respectively), but it only had between 88.6 and 91.0\% pair-wise sequence similarity to the rest of the family members. The MALDI-TOF assay reported no significant similarities for AK24(T) and AK26, since they potentially represented a new species. A MALDI MSP dendrogram showed close similarity between the two strains, but they maintained a distance from their phylogenetic neighbors. The genome of AK24(T) showed the presence of heavy metal tolerance genes, including the genes providing resistance to arsenic, cadmium, cobalt and zinc. A cluster of heat shock resistance genes was also found in the genome. Two lantibiotic producing genes, LanR and LasB, were also found in the genome of AK24(T). Strains AK24(T) and AK26 were very closely related to each other with 99.5\% pair-wise sequence similarity. Phylogenetic analysis indicated that the strains were members of the family Cyclobacteriaceae and they clustered with the genus Mariniradius, as well as with the genera Aquiflexum, Cecembia, Fontibacter, Indibacter, and Shivajiella. DNA-DNA hybridization between strains AK24(T) and AK26 showed a relatedness of 82\% and their rep-PCR banding patterns were very similar. Based on data from the current polyphasic study, it is proposed that the isolates be placed in a new genus and species with the name Lunatimonas lonarensis gen. nov., sp. nov. The type strain of Lunatimonas lonarensis is AK24(T) (=JCM 18822(T)=MTCC 11627(T)).

}, keywords = {Bacterial Typing Techniques, Bacteroidetes, Cluster Analysis, DNA, Bacterial, DNA, Ribosomal, Fatty Acids, Fresh Water, Genome, Bacterial, Geologic Sediments, India, Molecular Sequence Data, Nitrates, Oxidation-Reduction, Phospholipids, Phylogeny, Quinones, RNA, Ribosomal, 16S, Sequence Analysis, DNA}, issn = {1618-0984}, doi = {10.1016/j.syapm.2013.10.003}, author = {Srinivas, T N R and Aditya, S and Bhumika, V and Kumar, P Anil} } @article {517, title = {Two acidic, anticoagulant PLA2 isoenzymes purified from the venom of monocled cobra Naja kaouthia exhibit different potency to inhibit thrombin and factor Xa via phospholipids independent, non-enzymatic mechanism. (Mass Spectrometry - Proteomics)}, journal = {PLoS One}, volume = {9}, year = {2014}, month = {2014}, pages = {e101334}, abstract = {

BACKGROUND: The monocled cobra (Naja kaouthia) is responsible for snakebite fatality in Indian subcontinent and in south-western China. Phospholipase A2 (PLA2; EC 3.1.1.4) is one of the toxic components of snake venom. The present study explores the mechanism and rationale(s) for the differences in anticoagulant potency of two acidic PLA2 isoenzymes, Nk-PLA2α (13463.91 Da) and Nk-PLA2β (13282.38 Da) purified from the venom of N. kaouthia.

PRINCIPAL FINDINGS: By LC-MS/MS analysis, these PLA2s showed highest similarity (23.5\% sequence coverage) with PLA2 III isolated from monocled cobra venom. The catalytic activity of Nk-PLA2β exceeds that of Nk-PLA2α. Heparin differentially regulated the catalytic and anticoagulant activities of these Nk-PLA2 isoenzymes. The anticoagulant potency of Nk-PLA2α was comparable to commercial anticoagulants warfarin, and heparin/antithrombin-III albeit Nk-PLA2β demonstrated highest anticoagulant activity. The anticoagulant action of these PLA2s was partially contributed by a small but specific hydrolysis of plasma phospholipids. The strong anticoagulant effect of Nk-PLA2α and Nk-PLA2β was achieved via preferential, non-enzymatic inhibition of FXa (Ki = 43 nM) and thrombin (Ki = 8.3 nM), respectively. Kinetics study suggests that the Nk-PLA2 isoenzymes inhibit their "pharmacological target(s)" by uncompetitive mechanism without the requirement of phospholipids/Ca(2+). The anticoagulant potency of Nk-PLA2β which is higher than that of Nk-PLA2α is corroborated by its superior catalytic activity, its higher capacity for binding to phosphatidylcholine, and its greater strength of thrombin inhibition. These PLA2 isoenzymes thus have evolved to affect haemostasis by different mechanisms. The Nk-PLA2β partially inhibited the thrombin-induced aggregation of mammalian platelets suggesting its therapeutic application in the prevention of unwanted clot formation.

CONCLUSION/SIGNIFICANCE: In order to develop peptide-based superior anticoagulant therapeutics, future application of Nk-PLA2α and Nk-PLA2β for the treatment and/or prevention of cardiovascular disorders are proposed.

}, keywords = {Anticoagulants, Blood Platelets, Chemical Fractionation, Chromatography, Liquid, Cobra Venoms, Factor Xa, Factor Xa Inhibitors, Isoenzymes, Kinetics, Phospholipases A2, Phospholipids, Sequence Analysis, Protein, Tandem Mass Spectrometry, Thrombin}, issn = {1932-6203}, doi = {10.1371/journal.pone.0101334}, author = {Mukherjee, Ashis K and Kalita, Bhargab and Thakur, Rupamoni} }