Psychrotolerant antifungal Streptomyces isolated from Tawang, India and the shift in chitinase gene family

Debnath, Rajal; Saikia, Ratul; Sarma, Rupak K.; Yadav, Archana; Bora, Tarun C.; Handique, Pratap Jyoti

doi:10.1007/s00792-013-0587-8

Cited by 12 publications

(5 citation statements)

References 40 publications

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“…Antibacterial activity was expressed as the diameters of inhibition zones produced around each well by the plant extracts and antibiotics and was measured after 24 h of incubation at 37°C. Each test was conducted in triplicate to confirm the reproducibility of the observed data [ 13 ].…”

Section: Methodsmentioning

confidence: 99%

Citrus limon from Tunisia: Phytochemical and Physicochemical Properties and Biological Activities

Makni

Jemai

Kriaâ

et al. 2018

BioMed Research International

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Natural plant extracts contain a variety of phenolic compounds which are assigned various biological activities. Our work aims to make a quantitative and qualitative characterization of the Zest (ZL) and the Flesh (FL) of lemon (Citrus limon), to valorize the pharmacological uses of lemon, by evaluating in vitro activities (DPPH, free radical scavenging and reducing power). The antibacterial, antifungal, and antiproliferative activities were sought in the ability of Citrus limon extracts to protect DNA and protein. We found that the ZL contains high amounts of phenolics responsible for the important antioxidant properties of the extract. However, the FL is richer in flavonoids than the ZL. The FL extract was also found to be more effective than the ZL in protecting plasmid DNA against the strand breakage induced by hydroxyl radicals. We also concluded that the FL extract exhibited potent antibacterial activity unlike ZL. Analysis by LC/MS-MS identified 6 compounds (Caffeoyl N-Tryptophan, Hydroxycinnamoyl-Oglucoside acid, Vicenin 2, Eriocitrin, Kaempferol-3-O- rutinoside, and Quercetin-3-rutinoside). These preliminary results showed that Citrus limon has antibacterial and antioxidant activity in vitro. It would be interesting to conduct further studies to evaluate the in vivo potential in an animal model.

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Section: Methodsmentioning

confidence: 99%

Citrus limon from Tunisia: Phytochemical and Physicochemical Properties and Biological Activities

Makni

Jemai

Kriaâ

et al. 2018

BioMed Research International

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“…The poorly explored environments contain highest populations of actinomycetes with valuable antimicrobial secondary metabolites as reported by Ara et al ( 2007 ). Isolation of microorganisms from poorly explored areas of the world like Jordan (Saadoun and Gharaibeh, 2003 ), Antarctica (Lee et al, 2012 ), and certain ecological niches of Northeast India (Bordoloi et al, 2001 ; Debnath et al, 2013 ) reflects that these habitats should be carefully explored for novel microorganisms and their valuable bioactive products. Northeast India is a part of the Indo-Burma mega-biodiversity hotspot (Myers et al, 2000 ).…”

Section: Introductionmentioning

confidence: 99%

Broad Spectrum Antimicrobial Activity of Forest-Derived Soil Actinomycete, Nocardia sp. PB-52

2016

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A mesophilic actinomycete strain designated as PB-52 was isolated from soil samples of Pobitora Wildlife Sanctuary of Assam, India. Based on phenotypic and molecular characteristics, the strain was identified as Nocardia sp. which shares 99.7% sequence similarity with Nocardia niigatensis IFM 0330 (NR_112195). The strain is a Gram-positive filamentous bacterium with rugose spore surface which exhibited a wide range of antimicrobial activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative bacteria, and yeasts. Optimization for the growth and antimicrobial activity of the strain PB-52 was carried out in batch culture under shaking condition. The optimum growth and antimicrobial potential of the strain were recorded in GLM medium at 28°C, initial pH 7.4 of the medium and incubation period of 8 days. Based on polyketide synthases (PKS) and non-ribosomal peptide synthetases (NRPS) gene-targeted PCR amplification, the occurrence of both of these biosynthetic pathways was detected which might be involved in the production of antimicrobial compounds in PB-52. Extract of the fermented broth culture of PB-52 was prepared with organic solvent extraction method using ethyl acetate. The ethyl acetate extract of PB-52 (EA-PB-52) showed lowest minimum inhibitory concentration (MIC) against S. aureus MTCC 96 (0.975 μg/mL) whereas highest was recorded against Klebsiella pneumoniae ATCC 13883 (62.5 μg/mL). Scanning electron microscopy (SEM) revealed that treatment of the test microorganisms with EA-PB-52 destroyed the targeted cells with prominent loss of cell shape and integrity. In order to determine the constituents responsible for its antimicrobial activity, EA-PB-52 was subjected to chemical analysis using gas chromatography-mass spectrometry (GC-MS). GC-MS analysis showed the presence of twelve different chemical constituents in the extract, some of which are reported to possess diverse biological activity. These results confirmed that the presence of bioactive constituents in EA-PB-52 could be a promising source for the development of potent antimicrobial agents effective against wide range of microbial pathogens including MRSA.

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“…Hence, actinobacteria may be a potential solution to these problems. In order to find new microbial products derived from newly identified activities of actinobacteria, the search has to be shifted from routinely explored ecological niches to unexplored ones 13,14 .…”

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confidence: 99%

Antimicrobial biosynthetic potential and diversity of culturable soil actinobacteria from forest ecosystems of Northeast India

Sharma

Thakur²

2020

Sci Rep

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Actinobacteria is a goldmine for the discovery of abundant secondary metabolites with diverse biological activities. this study explores antimicrobial biosynthetic potential and diversity of actinobacteria from Pobitora Wildlife Sanctuary and Kaziranga National Park of Assam, India, lying in the Indo-Burma mega-biodiversity hotspot. A total of 107 actinobacteria were isolated, of which 77 exhibited significant antagonistic activity. 24 isolates tested positive for at least one of the polyketide synthase type I, polyketide synthase type II or non-ribosomal peptide synthase genes within their genome. their secondary metabolite pathway products were predicted to be involved in the production of ansamycin, benzoisochromanequinone, streptogramin using DoBISCUIT database. Molecular identification indicated that these actinobacteria predominantly belonged to genus Streptomyces, followed by Nocardia and Kribbella. 4 strains, viz. Streptomyces sp. PB-79 (GenBank accession no. KU901725; 1313 bp), Streptomyces sp. Kz-28 (GenBank accession no. KY000534; 1378 bp), Streptomyces sp. Kz-32 (GenBank accession no. KY000536; 1377 bp) and Streptomyces sp. Kz-67 (GenBank accession no. KY000540; 1383 bp) showed ~89.5% similarity to the nearest type strain in EzTaxon database and may be considered novel. Streptomyces sp. Kz-24 (GenBank accession no. KY000533; 1367 bp) showed only 96.2% sequence similarity to S. malaysiensis and exhibited minimum inhibitory concentration of 0.024 µg/mL against methicilin resistant Staphylococcus aureus ATCC 43300 and Candida albicans MTCC 227. This study establishes that actinobacteria isolated from the poorly explored Indo-Burma megabiodiversity hotspot may be an extremely rich reservoir for production of biologically active compounds for human welfare. Since ancient times, mankind has been exploring nature for bioactive organisms to treat different ailments. More than 100000 natural products have been identified in the last 150 years, which include highly assorted chemical classes such as polyketides, alkaloids, non-ribosomal peptides, isoprenoids or phenylpropanoids 1,2. Microbial biodiversity can provide us with the richest and the most versatile reservoir of potentially active natural products. A large portion of genomes from beneficial microbes are dedicated to the production of these valuable natural products. A single microbe is capable of making 30-50 natural product compounds 3. There are approximately 1 million natural products out of which about 25% are biologically active showing either positive activity or toxicity. Among the prospective sources of natural products, bacteria are prolific sources and a vast majority of these products are produced by a phylum of Gram-positive bacteria known as the "Actinobacteria" 4-6. Actinobacteria are diverse group of bacteria with high content of guanosine-cytosine (65-75%) ranging from 2.5-9.7 Mb genome size 7. Among actinobacteria, about 75% of antibiotics such as ivermectin, streptomycin, nystatin and tetracycline are produced by the microbial world's...

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Psychrotolerant antifungal Streptomyces isolated from Tawang, India and the shift in chitinase gene family

Cited by 12 publications

References 40 publications

Citrus limon from Tunisia: Phytochemical and Physicochemical Properties and Biological Activities

Citrus limon from Tunisia: Phytochemical and Physicochemical Properties and Biological Activities

Broad Spectrum Antimicrobial Activity of Forest-Derived Soil Actinomycete, Nocardia sp. PB-52

Antimicrobial biosynthetic potential and diversity of culturable soil actinobacteria from forest ecosystems of Northeast India

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