Objective: Research of isolates producing antifungal activity. Material and methods: An actinomycetes strain having anti-Aspergillus activity against multidrug drug resistant clinical isolates was isolated from marine sediment samples collected at Marakkanam coast of Bay of Bengal, India. The strain was characterized by polyphasic taxonomic approach and identified as a member of the genus . Streptomyces. Based on the phenotypic and phylogenetic analysis, the strain was classified as a new species of the genus . Streptomyces and designated as . Streptomyces VITSVK5 spp. The G. +. C content of the isolated DNA is 71.3 mol% and the 16S rDNA sequence of the strain showed 93% similarity with . Streptomyces MSU2261. The media and growth conditions were optimized for maximal growth under shake flask conditions by measuring the dry weight of mycelium. Eleven multidrug resistant (MDR) . Aspergillus strains were isolated from sputum samples collected voluntarily from the pulmonary tuberculosis patients. Results: The isolated MDR strains showed the MIC value between 4-16μg/ml against the tested antifungal drugs, amphotericin B, itraconazole, ketoconazole and fluconazole. Ethyl acetate crude extract of . Streptomyces VITSVK5 spp. exhibited significant antifungal activity against MDR strains with the zone of inhibition ranging from 22 to 28. mm and the MIC value of 0.125-4μg/ml. Conclusion: The isolated . Streptomyces is a good candidate for the extraction and the purification of its antifungal metabolite. © 2010 Elsevier Masson SAS.

Kannabiran K

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Vellore Campus

Kumar S

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal de Mycologie Médicale

Streptomyces are among the most promising genera in terms of production ability to biosynthesize a variety of bioactive secondary metabolites with pharmaceutical interest. Coinciding with the increase in genomic sequencing of these bacteria, mining of their genomes for biosynthetic gene clusters (BGCs) has become a routine component of natural product discovery. Herein, we describe the isolation and characterization of a Streptomyces tendae VITAKN with quorum sensing inhibitory (QSI) activity that was isolated from southern coastal part of India. The nearly complete genome consists of 8,621,231bp with a GC content of 72.2%. Sequence similarity networks of the BGCs detected from this strain against the Minimum Information about a Biosynthetic Gene Cluster (MIBiG) database and 3365 BGCs predicted by antiSMASH analysis of publicly available complete Streptomyces genomes were generated through the BiG-SCAPE-CORASON platform to evaluate its biosynthetic novelty. Crude extract analysis using high-performance liquid chromatography connected to high resolution tandem mass spectrometry (HPLC-HRMS/MS) and dereplication through the Global Natural Product Social Molecular Networking (GNPS) online workflow resulted in the identification of cyclic dipeptides (2, 5-diketopiperazines, DKPs) in the extract, which are known to possess QSI activity. Our results highlight the potential of genome mining coupled with LC-HRMS/MS and in silico tools (GNPS) as a valid approach for the discovery of novel QSI lead compounds. This study also provides the biosynthetic diversity of BGCs and an assessment of the predicted chemical space yet to be discovered.

Fulltext

Microorganisms

Isolation, Genomic and Metabolomic Characterization of Streptomyces tendae VITAKN with Quorum Sensing Inhibitory Activity from Southern India

Antimicrobials

Aspergillosis and its resistance: Marine natural products as future treatment

Emergence of antibiotic resistance by bacteria has become a serious threat for public health worldwide. In this study, Streptomyces isolated from fertile soil sample was tested for biosynthesis of silver nanoparticles (AgNps) using cell-free supernatant and synthesized AgNps were screened for anti-ESBL (extended spectrum b-lactamase) activity against multi-drug resistant (MDR) ESBL-producing strain Klebsiella pneumoniae (ATCC 700603) and other medically important pathogens. Synthesis of AgNps was confirmed by change in pale yellow color to dark brown color and characteristic absorption spectra at 420 nm. The XRD spectrum displayed typical peaks of crystalline silver and EDAX analysis showed a major signal for silver. FTIR spectra revealed prominent peaks at 3,294 cm-1 (NH stretching due to amide group), 2,952 cm-1 (aldehydic C-H stretching) 1,658 cm-1 indicating the presence of carbonyl group. AgNps were spherical in shape with size ranging from 20 to 70 nm. The synthesized AgNps showed significant antimicrobial activity against standard ESBL pathogen K. pneumoniae (22 mm), 21 mm against clinical ESBL isolate E. coli and 16 mm against clinical ESBL isolates K. pneumoniae and Citrobacter species, respectively. The results of this study suggest that AgNps synthesized by Streptomyces sp. VITSJK10 can be used as a potential alternative to control MDR ESBL pathogens. The present study aimed for green synthesis of AgNps using Streptomyces species and to explore its anti-ESBL activity. © Springer-Verlag 2013.

Bioprocess and Biosystems Engineering

Anti-ESBL activity of silver nanoparticles biosynthesized using soil Streptomyces species

Antifungal drugs are inhibitors either of fungal cell wall biosynthesis or essential reaction steps of fungal metabolic pathways. In silico studies have proved to be very effective on screening small molecules to be used as drugs and identifying essential reactions and pathways as targets. The aim of the present study was to predict the interactions of compounds present in the ethyl acetate extract of Streptomyces sp. VITSTK7 against selected fungal drug target enzymes. The ethyl acetate extract of the isolate showed significant anti-Aspergillus activity against the selected Aspergillus pathogens. Presence of the three compounds (C22H37NO7, C17H24N4O6 and C24H28N2O5) in the extract was identified by GC-MS spectra and matched with reference compounds available in the MS spectra library, NIST (National Institute for Standards and Technology). These compounds were analysed for the interaction with five selected fungal target proteins 1AFR, 1EA1, 1LKP, 1ZHX and 3PD73i3E. Docking was done using Patch dock beta 1.3 version and analysed by pymol 1.3 version. The tested compounds C22H37NO7, C17H24N4O6 and C24H28N2O5 showed least binding energy of -254.64 kcal/mol, -248.71 kcal/mol and -338.57 kcal/mol respectively with 1ZHX. The result of this study revealed that all the three compounds from the strain had higher interaction with 1ZHX protein than with the other proteins. It shows that this strain could be the promising source for the antifungal drug. © 2013 International Association of Scientists in the Interdisciplinary Areas and Springer-Verlag Berlin Heidelberg.

Interdisciplinary Sciences: Computational Life Sciences

Interaction of Streptomyces sp. VITSTK7 compounds with selected antifungal drug target enzymes by in silico molecular docking studies

The aim of the present study was to assess the larvicidal property of marine actinobacterial compound 5-(2,4-dimethylbenzyl) pyrrolidin-2-one (DMBPO) extracted and isolated from Streptomyces VITSVK5 sp. tested against the larvae of Rhipicephalus (Boophilus) microplus Canestrini (Acari: Ixodidae), Anopheles stephensi Liston, and Culex tritaeniorhynchus Giles (Diptera: Culicidae). The isolate bacteria was taxonomically characterized, identified, and designated as Streptomyces VITSVK5 sp. The crude extract was loaded on silica gel column and eluted with chloroform:methanol. The isolated pure compound was analyzed by thin layer chromatography using chloroform and methanol as the solvent system and confirmed by high-performance liquid chromatography. The structure of the purified compound was established from infrared, ultraviolet, 1H-nuclear magnetic resonance (NMR), 13C-NMR, and mass spectral data. The chemical shift assignments obtained for the aliphatic compound from 1H-NMR corresponding to the molecular formula C 13H17NO. Bioassay-guided fractionation led to the isolation of compound which was identified as DMBPO. In the present study, Streptomyces VITSVK5 sp. crude extract and different fractions were tested against the larvae of parasites at the concentration of 1,000 ppm. Those fractions showing 100% mortality in 24 h alone was selected for further column chromatographic separation. The purified compound, C13H 17NO, was tested in the concentrations of 500, 250, 125, 62.5, and 31.25 ppm and observed the percent larval mortality of 100, 70, 64, 40, and 28 against R. microplus; 100, 79, 63, 36, and 22 against A. stephensi; and 100, 84, 67, 42, and 27 against C. tritaeniorhynchus, respectively. The crude extract showed parasitic effects after 24 h of exposure at 1,000 ppm, and parasite mortality was observed against the larvae of R. microplus (LC50 = 210.39 ppm, r 2 = 0.873); A. stephensi (LC50 = 169.38 ppm, r 2 = 0.840); and C. tritaeniorhynchus (LC50 = 198.75 ppm, r 2 = 0.887). The maximum efficacy was observed in purified marine actinobacterial compound DMBPO with LC50 and r 2 values against the larvae of R. microplus (84.31 ppm, 0.889); A. stephensi (88.97 ppm, 0.817), and C. tritaeniorhynchus (74.95 ppm, 0.781), respectively. The control (distilled water) showed nil mortality in the concurrent assay. © 2011 Springer-Verlag.

Parasitology Research

Larvicidal activity of isolated compound 5-(2,4-dimethylbenzyl) pyrrolidin-2-one from marine Streptomyces VITSVK5 sp. against Rhipicephalus (Boophilus) microplus, Anopheles stephensi, and Culex tritaeniorhynchus

A moderately halophilic actinomycete strain was isolated from marine sediments collected at the Marakkanam coast of Tamil Nadu, India. The taxonomic position was evaluated by polyphasic approach and the strain was identified as a member of the genus Streptomyces. The strain is congruent with the description of the genus Streptomyces due to the characteristics of white aerial cell mass, spiral spore chains and a rough spore surface, menaquinones of MK-9 (H4, H2 and H6) types and belongs to cell-wall type I. The G + C content of the isolated DNA is 71.3 mol% and the 16S rRNA sequence of the strain shows a maximum of 93% similarity with Streptomyces HBUM 49447. The comparison of phenotypic data of closest strains with the isolate clearly indicates that our strain belongs to the genus Streptomyces. Based on the phenotypic and phylogenetic analysis, the strain was classified as a new species of the genus Streptomyces and designated as VITSDK1. The media and cultural conditions for maximal growth have been optimized under shake-flask conditions by measuring the dry weight of the mycelium. The maximal growth was attained with the use of optimized production medium, pH of 7.2 and incubation temperature of 27 °C. The growth of the strain was salt concentration dependent and maximal growth was attained at 15% salt concentration which indicates the halophilic nature of the isolate. Streptomyces VITSDK1 spp. exhibits significant hemolytic activity against rat erythrocytes with the EC50 value of 127 μg/ml and for human erythrocytes 168 μg/ml. Further, it shows moderate antibiosis against fungi and bacterial pathogens. © 2009 Elsevier Masson SAS. All rights reserved.

Hemolytic activity of Streptomyces VITSDK1 spp. isolated from marine sediments in Southern India

WHO South-East Asia Journal of Public Health

Health risks of climate change in the World Health Organization South-East Asia Region

Acta Biochimica Polonica

Fungi pathogenic to humans: molecular bases of virulence of Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus.

Nature Chemical Biology

Therapeutic treasures from the deep

Journal of Biological Sciences

Screening of Antagonistic Activity in Different Streptomyces Species Against Some Pathogenic Microorganisms

Antifungal activity of Streptomyces VITSVK5 spp. against drug resistant Aspergillus clinical isolates from pulmonary tuberculosis patients

Journal	Data powered by TypesetJournal de Mycologie Médicale
Publisher	Data powered by TypesetElsevier BV
ISSN	1156-5233
Open Access	0