02270nas a2200241   4500008004100000245007000041210006900111260000900180300001600189490000700205520148900212100002201701700002301723700002401746700001601770700002001786700002801806700002501834700002301859700002101882700002301903856010201926       2020                        eng d00aApproach to nigericin derivatives and their therapeutic potential0 aApproach to nigericin derivatives and their therapeutic potentia  cNOV   a43085-430910 v103 a<p>A new nigericin analogue that has been chemically modified was synthesized through a fluorination process from the parent nigericin, produced from a novel Streptomyces strain DASNCL-29. Fermentation strategies were designed for the optimised production of nigericin molecule and subjected for purification and structural analysis. The fermentation process resulted in the highest yield of nigericin (33% (w/w)). Initially, nigericin produced from the strain DASNCL-29 demonstrated polymorphism in its crystal structure, i.e., monoclinic and orthorhombic crystal lattices when crystallised with methanol and hexane, respectively. Furthermore, nigericin produced has been subjected to chemical modification by fluorination to enhance its efficacy. Two fluorinated analogues revealed that they possess a very potent antibacterial activity against Gram positive and Gram negative bacteria. To date, the nigericin molecule has not been reported for any reaction against Gram-negative bacteria, which are increasingly becoming resistant to antibiotics. For the first time, fluorinated analogues of nigericin have shown promising activity. In vitro cytotoxicity analysis of fluorinated analogues demonstrated tenfold lesser toxicity than the parent nigericin. This is the first type of study where the fluorinated analogues of nigericin showed very encouraging activity against Gram-negative organisms; moreover, they can be used as a candidate for treating many serious infections.</p>
1 aSahu, Amit, Kumar1 aSaid, Madhukar, S.1 aHingamire, Tejashri1 aGaur, Megha1 aKhan, Abujunaid1 aShanmugam, Dhanasekaran1 aBarvkar, Vitthal, T.1 aDharne, Mahesh, S.1 aBharde, Atul, A.1 aDastager, Syed, G.  uhttps://library.ncl.res.in/content/approach-nigericin-derivatives-and-their-therapeutic-potential02733nas a2200349   4500008004100000022001400041245012900055210006900184260000800253300001400261490000800275520154800283653001901831653002001850653001301870653001801883653002601901100002801927700002201955700002801977700002202005700002202027700001902049700002702068700002202095700002902117700003802146700002302184700002702207700001802234856013102252       2023                        eng d  a0273-228900aAntibacterial and anti-HIV metabolites from marine streptomyces albus MAB56 isolated from Andaman and Nicobar Islands, India0 aAntibacterial and antiHIV metabolites from marine streptomyces a  cDEC  a7738-77540 v1953 a<p>
	Marine-derived actinobacteria have tremendous potential to produce novel metabolites with diverse biological activities. The Andaman coast of India has a lot of microbial diversity, but it is still a relatively unknown ecology for isolating novel actinobacteria with beneficial bioactive compounds. We have isolated 568 actinobacterial strains from mangrove rhizosphere sediments and sponge samples. Crude extracts from 75 distinct strains were produced by agar surface fermentation and extracted using ethyl acetate. In the disc diffusion method, 25 actinobacterial strains showed antimicrobial activity; notably, the strain MAB56 demonstrated promising broad-spectrum activity. Strain MAB56 was identified as Streptomyces albus by cultural, microscopic, and molecular methods. Conditions for bioactive metabolites from MAB56 were optimized and produced in a lab-scale fermenter. Three active metabolites (C1, C2, and C3) that showed promising broad-spectrum antimicrobial activity were isolated through HPLC-based purification. Based on the UV, FT-IR, NMR, and LC-MS analysis, the chemical nature of the active compounds was confirmed as 12-methyltetradecanoic acid (C1), palmitic acid (C2), and tridecanoic acid (C3) with molecular formulae C14H28O2, C16H32O2, and C13H26O2, respectively. Interestingly, palmitic acid (C2) also exhibited anti-HIV activity with an IC50 value of &lt; 1 mu g/ml. Our findings reveal that the actinobacteria from the Andaman marine ecosystems are promising for isolating anti-infective metabolites.</p>
10aactinobacteria10aAndaman Islands10aanti-HIV10aAntibacterial10aBioactive metabolites1 aManikkam, Radhakrishnan1 aMurthy, Sangeetha1 aPalaniappan, Sivasankar1 aKaari, Manigundan1 aSahu, Amit, Kumar1 aSaid, Madhukar1 aGanesan, Vijayalakshmi1 aKannan, Sivakumar1 aRamasamy, Balagurunathan1 aThirugnanasambandan, Somasundaram1 aDastager, Syed, G.1 aHanna, Luke, Elizabeth1 aKumar, Vanaja  uhttps://library.ncl.res.in/content/antibacterial-and-anti-hiv-metabolites-marine-streptomyces-albus-mab56-isolated-andaman-and