Dataset Information

Antimicrobial potentiality of actinobacteria isolated from two microbiologically unexplored forest ecosystems of Northeast India.

ABSTRACT: BACKGROUND:Actinobacteria are often known to be great producers of antibiotics. The rapid increase in the global burden of antibiotic-resistance with the concurrent decline in the discovery of new antimicrobial molecules necessitates the search for novel and effective antimicrobial metabolites from unexplored ecological niches. The present study investigated the antimicrobial producing actinobacterial strains isolated from the soils of two microbiologically unexplored forest ecosystems, viz. Nameri National Park (NNP) and Panidehing Wildlife Sanctuary (PWS), located in the Eastern Himalayan Biodiversity hotspot region. RESULTS:A total of 172 putative isolates of actinobacteria were isolated, of which 24 isolates showed strong antimicrobial bioactivity. Evaluation of the ethyl acetate extracts of culture supernatants against test microbial strains revealed that isolates PWS22, PWS41, PWS12, PWS52, PWS11, NNPR15, NNPR38, and NNPR69 were the potent producers of antimicrobial metabolites. The antimicrobial isolates dominantly belonged to Streptomyces, followed by Nocardia and Streptosporangium. Some of these isolates could be putative novel taxa. Analysis of the antimicrobial biosynthetic genes (type II polyketide synthase and nonribosomal peptide synthetase genes) showed that the antimicrobial metabolites were associated with pigment production and belonged to known families of bioactive secondary metabolites. Characterization of the antimicrobial metabolites of Streptomyces sp. PWS52, which showed lowest taxonomic identity among the studied potent antimicrobial metabolite producers, and their interaction with the test strains using GC-MS, UHPLC-MS, and scanning electron microscopy revealed that the potential bioactivity of PWS52 was due to the production of active antifungal and antibacterial metabolites like 2,5-bis(1,1-dimethylethyl) phenol, benzeneacetic acid and nalidixic acid. CONCLUSIONS:Our findings suggest that the unexplored soil habitats of NNP and PWS forest ecosystems of Northeast India harbor previously undescribed actinobacteria with the capability to produce diverse antimicrobial metabolites that may be explored to overcome the rapidly rising global concern about antibiotic-resistance.

SUBMITTER: Das R

PROVIDER: S-EPMC6042205 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Antimicrobial potentiality of actinobacteria isolated from two microbiologically unexplored forest ecosystems of Northeast India.

Das Ranjita R Romi Wahengbam W Das Rictika R Sharma Hridip Kumar HK Thakur Debajit D

BMC microbiology 20180711 1

<h4>Background</h4>Actinobacteria are often known to be great producers of antibiotics. The rapid increase in the global burden of antibiotic-resistance with the concurrent decline in the discovery of new antimicrobial molecules necessitates the search for novel and effective antimicrobial metabolites from unexplored ecological niches. The present study investigated the antimicrobial producing actinobacterial strains isolated from the soils of two microbiologically unexplored forest ecosystems, ...[more]

PMID: 29996765

Similar Datasets

Project description:Actinomycetia are known for their ability to produce a wide range of bioactive secondary metabolites having significant therapeutic importance. This study aimed to explore the potential of actinomycetia as a source of bioactive compounds with antimicrobial properties against multi-drug-resistant (MDR) clinical pathogens. A total of 65 actinomycetia were isolated from two unexplored forest ecosystems, namely the Pobitora Wildlife Sanctuary (PWS) and the Deepor Beel Wildlife Sanctuary (DBWS), located in the Indo-Burma mega-biodiversity hotspots of northeast India, out of which 19 isolates exhibited significant antimicrobial activity. 16S rRNA gene sequencing was used for the identification and phylogenetic analysis of the 19 potent actinomycetia isolates. The results reveal that the most dominant genus among the isolates was Streptomyces (84.21%), followed by rare actinomycetia genera such as Nocardia, Actinomadura, and Nonomuraea. Furthermore, seventeen of the isolates tested positive for at least one antibiotic biosynthetic gene, specifically type II polyketide synthase (PKS-II) and nonribosomal peptide synthetases (NRPSs). These genes are associated with the production of bioactive compounds with antimicrobial properties. Among the isolated strains, three actinomycetia strains, namely Streptomyces sp. PBR1, Streptomyces sp. PBR36, and Streptomyces sp. DBR11, demonstrated the most potent antimicrobial activity against seven test pathogens. This was determined through in vitro antimicrobial bioassays and the minimum inhibitory concentration (MIC) values of ethyl acetate extracts. Gas chromatography-mass spectrometry (GS-MS) and whole-genome sequencing (WGS) of the three strains revealed a diverse group of bioactive compounds and secondary metabolite biosynthetic gene clusters (smBGCs), respectively, indicating their high therapeutic potential. These findings highlight the potential of these microorganisms to serve as a valuable resource for the discovery and development of novel antibiotics and other therapeutics with high therapeutic potential.

Project description:Biomolecules from natural sources, including microbes, have been the basis of treatment of human diseases since the ancient times. Therefore, this study aimed to investigate the potential bioactivity of several actinobacteria isolates form Al-Jouf Desert, Saudi Arabia. Twenty-one actinobacterial isolates were tested for their antioxidant (flavonoids, phenolics, tocopherols and carotenoids) content, and biological activities, namely FRAP, DPPH, ABTS, SOS and XO inhibition, anti-hemolytic and anti-lipid peroxidation as well as their antibacterial and antiprotozoal activities. Accordingly, five isolates (i.e., Act 2, 12, 15, 19 and 21) were selected and their 90% ethanolic extracts were used. The phylogenetic analysis of the 16S rRNA sequences indicated that the most active isolates belong to genus Streptomyces. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites against different cancer types. Thus, the anti-blood cancer activity and the possible molecular mechanisms by which several Streptomyces species extracts inhibited the growth of different leukemia cells, i.e., HL-60, K562 and THP-1, were investigated. In general, the five active isolates showed cytotoxic activity against the tested cell lines in a dose dependent manner. Among the potent isolates, isolate Act 12 significantly decreased the cell viability and showed maximum cytotoxic activities against both HL-60 and K562 cells, while isolate Act 15 exhibited maximum cytotoxic activity against THP-1 cells. Moreover, Act 2 and Act 12 reduced cyclooxygenase (COX-2) and lipoxygenase (LOX) activity, which is involved in the proliferation and differentiation of cancer cells and may represent a possible molecular mechanism underlying leukemia growth inhibition. The bioactive antioxidant extracts of the selected Streptomyces species inhibited leukemia cell growth by reducing the COX-2 and LOX activity. Overall, our study not only introduced a promising natural alternative source for anticancer agents, but it also sheds light on the mechanism underlying the anticancer activity of isolated actinomycetes.

Project description:The search for novel bioactive metabolites continues to be of much importance around the world for pharmaceutical, agricultural, and industrial applications. Actinobacteria constitute one of the extremely interesting groups of microorganisms widely used as important biological contributors for a wide range of novel secondary metabolites. This study focused on the assessment of antimicrobial and antioxidant activity of crude extracts of actinobacterial strains. Western Ghats of India represents unique regions of biologically diverse areas called "hot spots". A total of 32 isolates were obtained from soil samples of different forest locations of Bisle Ghat and Virjapet situated in Western Ghats of Karnataka, India. The isolates were identified as species of Streptomyces, Nocardiopsis, and Nocardioides by cultural, morphological, and molecular studies. Based on preliminary screening, seven isolates were chosen for metabolites extraction and to determine antimicrobial activity qualitatively (disc diffusion method) and quantitatively (micro dilution method) and scavenging activity against DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS(2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals. Crude extracts of all seven isolates exhibited fairly strong antibacterial activity towards MRSA strains (MRSA ATCC 33591, MRSA ATCC NR-46071, and MRSA ATCC 46171) with MIC varying from 15.62 to 125 μg/mL, whereas showed less inhibition potential towards Gram-negative bacteria Salmonella typhi (ATCC 25241) and Escherichia coli (ATCC 11775) with MIC of 125-500 μg/mL. The isolates namely S1A, SS5, SCA35, and SCA 11 inhibited Fusariummoniliforme (MTCC 6576) to a maximum extent with MIC ranging from 62.5 to 250 μg/mL. Crude extract of SCA 11 and SCA 13 exhibited potent scavenging activities against DPPH and ABTS radicals. The results from this study suggest that actinobacterial strains of Western Ghats are an excellent source of natural antimicrobial and antioxidant compounds. Further research investigations on purification, recovery, and structural characterization of the active compounds are to be carried out.

Dataset Information

Antimicrobial potentiality of actinobacteria isolated from two microbiologically unexplored forest ecosystems of Northeast India.

Publications

Antimicrobial potentiality of actinobacteria isolated from two microbiologically unexplored forest ecosystems of Northeast India.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets