title: Antimicrobial potential and taxonomic investigation of piezotolerant Streptomyces sp. NIOT-Ch-40 isolated from deep-sea sediment.
abstract: Microbial-derived natural products from extreme niches such as deepsea are known to possess structural and functional novelty. With this background, the present study was designed to investigate the bioprospecting potential and systematics of a deep-sea derived piezotolerant bacterial strain NIOT-Ch-40, showing affiliation to the genus Streptomyces based on 16S RNA gene similarity. Preliminary screening for the presence of biosynthetic genes like polyketide synthase I, polyketide synthase II, non ribosomal peptide synthase, 3-amino-5-hydroxybenzoic acid synthase and spiroindimicin followed by antibacterial activity testing confirmed the presence of potent bioactivity. The secondary metabolites produced during fermentation in Streptomyces broth at 28 °C for 7 days were extracted with ethyl acetate. The extract exhibited a specific inhibitory activity against Gram-positive bacteria and was significantly effective (p < 0.0001) against methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration and minimum bactericidal concentration against MRSA was 1.5 µg/mL, which was statistically significant in comparison with erythromycin. A multifaceted analysis of the Streptomyces spp. was carried out to delineate the strain NIOT-Ch-40 at a higher resolution which includes morphological, biochemical and molecular studies. Piezotolerance studies and comparison of fatty acid profiles at high pressures revealed that it could be considered as one of the taxonomic markers, especially for the strains isolated from the deep sea environments. In conclusion, the observation of comparative studies with reference strains indicated towards the strain NIOT-Ch-40 as an indigenous marine piezotolerant Streptomyces sp. with a higher probability of obtaining novel bioactive metabolites.
authors.affiliation: Centre for Biotechnology, Anna University, Chennai, Tamil Nadu, 600025, India.
authors.forename: Vishnu Priya
authors.initials: VP
authors.lastname: Padmanaban
authors.affiliation: Marine Biotechnology Division, OSTI Group, National Institute of Ocean Technology, Ministry of Earth Sciences, Government of India, Chennai, Tamil Nadu, 600100, India.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Verma
authors.affiliation: Marine Biotechnology Division, OSTI Group, National Institute of Ocean Technology, Ministry of Earth Sciences, Government of India, Chennai, Tamil Nadu, 600100, India.
authors.forename: Srividhyalakshmi
authors.initials: S
authors.lastname: Venkatabaskaran
authors.affiliation: Marine Biotechnology Division, OSTI Group, National Institute of Ocean Technology, Ministry of Earth Sciences, Government of India, Chennai, Tamil Nadu, 600100, India.
authors.forename: Thirupathi
authors.initials: T
authors.lastname: Keppayan
authors.affiliation: Marine Biotechnology Division, OSTI Group, National Institute of Ocean Technology, Ministry of Earth Sciences, Government of India, Chennai, Tamil Nadu, 600100, India.
authors.forename: Dharani
authors.initials: D
authors.lastname: Gopal
authors.affiliation: Centre for Biotechnology, Anna University, Chennai, Tamil Nadu, 600025, India. ashokkumar@annauniv.edu.
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Sekar
authors.affiliation: Marine Biotechnology Division, OSTI Group, National Institute of Ocean Technology, Ministry of Earth Sciences, Government of India, Chennai, Tamil Nadu, 600100, India. kiruba@niot.res.in.
authors.forename: Kirubagaran
authors.initials: K
authors.lastname: Ramalingam
mesh_terms: D000890:Anti-Infective Agents / Q000378:metabolism / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D053898:Biosynthetic Pathways; D005285:Fermentation; D019015:Geologic Sediments / Q000382:microbiology*; D006094:Gram-Positive Bacteria / Q000187:drug effects; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D064210:Secondary Metabolism; D017423:Sequence Analysis, RNA / Q000379:methods; D013302:Streptomyces / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Bioactivity; Deep sea bacteria; MRSA; Piezotolerance; Strain characterization; Streptomyces