@article {46902, title = {Antimicrobial profiling of coral reef and sponge associated bacteria from southeast coast of India}, volume = {141}, year = {2020}, month = {APR}, pages = {103972}, type = {Article}, abstract = {

Culturable bacteria associated with marine sponges and coral mucus (collected from Gulf of Mannar and Palk Bay) were screened for their prospective antimicrobial compounds against 9 bacterial pathogens (Bacillus megaterium, B. cereus, Salmonella typhimurium, Staphylococcus aureus, Proteus vulgaris, Klebsillla pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii) and a fungal pathogen (Candida albicans). Of the 263 bacterial isolates obtained during this study, 52 isolates displayed antimicrobial activity against one or more pathogens. 16S rRNA gene sequencing revealed that these 52 strains affiliated to 14 genera from three phyla Proteobacteria, Firmicutes and Actinobacteria. Sponge associated bacterial strains F-04, 1-23, 1-33 and G-03 inhibited the growth of all the bacterial pathogens tested in this study and significantly the former 2 strains inhibited the growth of fungal pathogen also. Majority of the potential strains (88.4\% out of 52 strains) inhibited the growth of Bacillus cereus. Interestingly, an actinomycete strain F-04 (isolated from sponge Orina sagittaria) inhibited the growth of methicillin resistant Staphylococcus aureus. In total, 10 volatile organic compounds were determined from the ethyl acetate and hexane extract of the strain F-04 using GC-MS. Overall, marine bacteria isolated during this study demonstrate the potential for the development of broad spectrum antibiotics.

}, keywords = {Anti-MRSA, Antimicrobial activity, Bacterial diversity, Coral reef, Sponge}, issn = {0882-4010}, doi = {10.1016/j.micpath.2020.103972}, author = {Rajasabapathy, Raju and Ghadi, Sanjeev C. and Manikandan, Balakrishnan and Mohandass, Chellandi and Surendran, Akhila and Dastager, Syed G. and Meena, Ram M. and James, Rathinam Arthur} } @article {46625, title = {Approach to nigericin derivatives and their therapeutic potential}, journal = {RSC Advances}, volume = {10}, year = {2020}, month = {NOV }, pages = {43085-43091}, type = {Article}, abstract = {

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.

}, doi = {10.1039/d0ra05137c}, author = {Sahu, Amit Kumar and Said, Madhukar S. and Hingamire, Tejashri and Gaur, Megha and Khan, Abujunaid and Shanmugam, Dhanasekaran and Barvkar, Vitthal T. and Dharne, Mahesh S. and Bharde, Atul A. and Dastager, Syed G.} } @article {48014, title = {Antifungal compound from marine Serratia marcescens BKACT and its potential activity against Fusarium sp.}, journal = {International Microbiology}, volume = {25}, year = {2022}, month = {NOV}, pages = {851-862}, type = {Article}, abstract = {

Ecofriendly biocontrol agents to control pathogenic fungi are in demand globally. The present study evaluated the antifungal potentials of marine bacteria Serratia marcescens BKACT against eight different Fusarium species. A highest 75.5 +/- 0.80\% of mycelial inhibition was observed against Fusarium foetens NCIM 1330. Structural characterization of the purified compound was analyzed by GC-MS and NMR techniques; based on the analysis, it is confirmed as 2, 4-di-tert butyl phenol (2, 4-DTBP) with chemical structure C14H22O. At 0.53 mM concentration, purified compound inhibited complete spore germination of F. foetens NCIM 1330. In vitro assay showed complete inhibition of F. foetens NCIM 1330 on the wheat seeds. Tested concentration does not show any toxic effect on germination of the seeds. By this study, we conclude that, 2, 4-DTBP is a suitable candidate to be used as biocontrol agent against Fusarium infection.

}, keywords = {2, 4, di-tert butyl phenol, Fusarium sp, marine, Serratia marcescens}, issn = {1139-6709}, doi = {10.1007/s10123-022-00268-3}, author = {Kharat, Bharat A. and Said, Madhukar S. and Dastager, Syed G.} } @article {48407, title = {Artificial intelligence in microbial natural product drug discovery: current and emerging role}, journal = {Natural Product Reports}, volume = {39}, year = {2022}, month = {DEC}, pages = {2215-2230}, type = {Review}, abstract = {

Covering: up to the end of 2022 Microorganisms are exceptional sources of a wide array of unique natural products and play a significant role in drug discovery. During the golden era, several life-saving antibiotics and anticancer agents were isolated from microbes; moreover, they are still widely used. However, difficulties in the isolation methods and repeated discoveries of the same molecules have caused a setback in the past. Artificial intelligence (AI) has had a profound impact on various research fields, and its application allows the effective performance of data analyses and predictions. With the advances in omics, it is possible to obtain a wealth of information for the identification, isolation, and target prediction of secondary metabolites. In this review, we discuss drug discovery based on natural products from microorganisms with the help of AI and machine learning.

}, issn = {0265-0568}, doi = {10.1039/d2np00035k}, author = {SahayaSheela, Vinodh J. and Lankadasari, Manendra B. and Dan, Vipin Mohan and Dastager, Syed G. and Pandian, Ganesh N. and Sugiyama, Hiroshi} } @article {49001, title = {Antibacterial and anti-HIV metabolites from marine streptomyces albus MAB56 isolated from Andaman and Nicobar Islands, India}, journal = {Applied Biochemistry and Biotechnology}, volume = {195}, year = {2023}, month = {DEC}, pages = {7738-7754}, type = {Article}, abstract = {

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 \< 1 mu g/ml. Our findings reveal that the actinobacteria from the Andaman marine ecosystems are promising for isolating anti-infective metabolites.

}, keywords = {actinobacteria, Andaman Islands, anti-HIV, Antibacterial, Bioactive metabolites}, issn = {0273-2289}, doi = {10.1007/s12010-023-04493-y}, author = {Manikkam, Radhakrishnan and Murthy, Sangeetha and Palaniappan, Sivasankar and Kaari, Manigundan and Sahu, Amit Kumar and Said, Madhukar and Ganesan, Vijayalakshmi and Kannan, Sivakumar and Ramasamy, Balagurunathan and Thirugnanasambandan, Somasundaram and Dastager, Syed G. and Hanna, Luke Elizabeth and Kumar, Vanaja} }