Dataset Information

Microbial diversity of a Himalayan forest and characterization of rare actinomycetes for antimicrobial compounds.

ABSTRACT: The slow pace of discovery of new effective drugs against multi-drug resistant pathogens and largely unsuccessful combinatorial chemistry has resulted in shifting the focus back to natural products as sources of lead molecules for antimicrobial drugs, mainly due to their structural diversity. Investigation of under-explored habitats for potentially novel microorganisms provides for wider chemodiversity. In this study, four actinomycetes, namely UK-274, UK-281, UK-282 and UK-285, which showed broad-spectrum antibacterial and antifungal activities, were isolated from Timli forest range of the biodiversity-rich Himalayan region. 16S rRNA gene sequence analysis showed that the nearest neighbours of the isolates were Actinomadura nitrigenes, Streptomyces niveiscabiei, and Kitasatospora psammotica with similarity values ranging between 97 and 98% suggesting their potential as new isolates. Further morphological and phenotypic characterization strengthened this assumption. Isolate UK-282, of the rare actinomycetes Kitasatospora group, was found to produce antimicrobial activity. Metabolite fingerprinting of ethyl acetate fraction of isolate UK-282 by GC-MS and 1H NMR analysis showed the presence of three novel compounds. The study underlines that a combination approach of bioprospecting of under-studied habitats and focus on rare actinomycetes may result in the identification of novel chemodiversity.

SUBMITTER: Srivastava N

PROVIDER: S-EPMC6314948 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Microbial diversity of a Himalayan forest and characterization of rare actinomycetes for antimicrobial compounds.

Srivastava Nidhi N Nandi Ipsita I Ibeyaima Ahongshangbam A Gupta Sanjay S Sarethy Indira P IP

3 Biotech 20190102 1

The slow pace of discovery of new effective drugs against multi-drug resistant pathogens and largely unsuccessful combinatorial chemistry has resulted in shifting the focus back to natural products as sources of lead molecules for antimicrobial drugs, mainly due to their structural diversity. Investigation of under-explored habitats for potentially novel microorganisms provides for wider chemodiversity. In this study, four actinomycetes, namely UK-274, UK-281, UK-282 and UK-285, which showed bro ...[more]

PMID: 30622865

Similar Datasets

Project description:Background and objectivesRare actinomycetes are a promising source of novel metabolites of pharmaceutical importance. The current study focussed on selective isolation of specific genera of rare actinomycetes and screening the isolates for biosynthetic genes particularly polyketide synthases (PKS) and non ribosomal peptide synthetases (NRPS).Materials and methodsThe soil samples were subjected to various pre-treatments like 1.5% phenol treatment, 0.3% chloramine T treatment, benzethonium chloride treatment, etc. and plated on selective media supplemented with specific antibiotics targeting rare genera of actinomycetes. The putative rare actinomycete isolates were screened for bioactivity using agar cross streak method and agar well diffusion method. The ability of the isolates to produce anti-quorum sensing compounds was tested against Serratia marcescens. The isolates were also screened for the presence of biosynthetic gene clusters associated with PKS-I, PKS-II and NRPS pathways using the degenerate primer sets K1F-M6R, KSα/KSβ and A3FA7R, respectively. The expression of these gene clusters was tracked by physicochemical screening of the extracts of isolates using spectroscopic and chromatographic techniques.ResultsIn this study, 1.5% phenol treatment was found to be the most promising followed by heat treatment and chloramine treatment. Our studies showed that ISP5 agar was the best for isolation of rare genera followed by ISP7, Starch Caesin agar and ISP2 supplemented with antibiotics like gentamicin, nalidixic acid and streptomycin. Micromonospora was the most abundant genus followed by Dactylosporangium. Actinomadura, Nocardiopsis and Actinoplanes were almost equal in number. Primary screening showed that 92% of the isolates were active against one of the test organisms. Thirty seven isolates were found to produce anti-quorum sensing (QS) compounds. NRPS sequences were detected in thirty nine isolates (42.8%), whereas PKS-I and PKS-II sequences were detected in seventeen and twenty eight strains (18.6% and 30.7%), respectively.ConclusionNine type I and type II polyketide-producing isolates as well as six peptide-producing isolates were found. The peptide extract of isolate KCR3 and a polyketide extract of isolate NCD10 were found to possess anti-tumor activity exhibiting an IC50 value of 3 μg/ml and 2.5 μg/ml against HeLa cells.

Project description:Actinomycetes are Gram-positive, facultative anaerobic fungus-like filamentous bacteria which remain on the top of the natural antibiotic producers. Due to the climatic and geographical diversity of Nepal, a wide range of microorganisms with potent source of antimicrobials are available. The objective of this study was to isolate, identify, and screen the potential antimicrobial-producing actinomycetes from soils covering different altitude range of Nepal. Forty-one isolates of actinomycetes were isolated from 11 soil samples collected from different locations in Nepal with altitude ranging from 1500 to 4380 meters. The isolates were identified on the basis of morphological study, different sugar utilization, protein utilization, and hydrolysis tests. They were also characterized on the basis of temperature and pH. Primary screening for antimicrobial activity was carried out against several test organisms: Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), and Pseudomonas aeruginosa (ATCC 27853) by the perpendicular streaking method, and secondary screening was carried out by the agar well diffusion method using ethyl acetate for solvent extraction. 70.7% of the isolates were identified as Streptomyces spp., 19.5% as Nocardia spp., and 9.5% as Micromonospora spp. 43.34% of actinomycete isolates was found to be potent antimicrobial producers from the primary screening among which 46.34% were effective against Gram-positive and 12.19% against Gram-negative test organisms. Isolate C7 (Micromonospora spp.) showed the best broad-spectrum antimicrobial activity during secondary screening. A total of 11 different types of pigments were observed to be produced by different isolates, of which, the yellow pigment was the most prominent. The association between elevation, pH, and pigment with the antimicrobial production was found to be insignificant. This finding can be of importance for further investigation towards obtaining broad-spectrum antibiotics for therapeutic purpose.

Project description:Antibiotic resistance is one of the most important global healthcare challenges and is responsible for the mortality of millions of people worldwide every year. It is a crisis attributed to misuse of antibiotics and a lack of new drug development. Actinomycetes constitute a group of Gram-positive bacteria known for their distinctive high guanine-cytosine (G+C) content in their genomic DNA. These microorganisms are widely recognized for their capability to generate a wide range of secondary metabolites with diverse biological activities. These versatile microorganisms are ubiquitous in diverse ecosystems, including soil, freshwater, marine sediments, and within the bodies of insects. A recent study has demonstrated that social insects, such as ants, host a diverse array of these bacteria. In this study, we involved the isolation and characterization of a total of 72 actinomycete strains obtained from 18 distinct ant species collected from various regions across Thailand. Utilizing 16S rRNA gene analysis, these isolated actinomycetes were classified into four distinct genera: Amycolatopsis (2 isolates), Micromonospora (1 isolate), Nocardia (8 isolates), and Streptomyces (61 isolates). Among the Streptomyces strains, 23 isolates exhibited antimicrobial activity against a panel of Gram-positive bacteria, including Bacillus subtilis ATCC 6633, Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 25923, Kocuria rhizophila ATCC 9341, and Methicillin-resistant Staphylococcus aureus (MRSA) DMST 20646. Additionally, two isolates displayed antifungal activity against Candida albicans TISTR 5554. Based on 16S rRNA gene sequence similarity studies, these two isolates, ODS25 and ODS28, were demonstrated to be closely related to Streptomyces lusitanus NBRC 13464T (98.07%) and Streptomyces haliclonae DSM 41970T (97.28%), respectively. The level of 16S rRNA gene sequence similarity below 98.65% cutoff indicates its potential as a novel actinomycete species. These findings underscore the potential of actinomycetes sourced from ants as a valuable reservoir of novel antimicrobials.

Project description:BackgroundActinomycetes widely exist in nature and these species cause infections in immunocompromised and healthy patients, although they are frequently found as members of the normal microbiota of humans and animals. These subsequent infections are often misdiagnosed as malignancy and tuberculosis. Due to this issue, the present study aimed to determine the presence and diversity of actinomycetes species causing infections in Iranian patients.Materials and methodsA total of 79 clinical samples collected from five hospitals in Markazi province were analyzed for the existence of actinomycetes using standard protocols for isolation and characterization of the isolates. The conventional tests were used for preliminary identification, the PCR amplification of hsp65 gene, the specific region of the 16S rRNA, and sequence analyses of 16S rRNA were applied for the genus and species identification. MICs of the antimicrobial agent were determined by the broth microdilution method and interpreted according to the NCCLS guidelines.ResultsA total of 17 (21.51%) actinomycetes isolates were recovered from clinical samples. In other analyzed samples, eight (10.12%) gram-positive, 12 (15.18) gram-negative bacteria, and six (7.6) fungi isolates were recovered. The most prevalent actinomycetes species were M. fortuitum (17.64%), N. Mexicana and S. heliomycini (11.76% each), and 10 species, ie, N. farcinica, M. lehmannii, M. flavescens, Arthrobacter crystalopoetis, N. neocaledoniensis, M. phocaicum, M. abscessus, M. arupense, M. setense, and N. cyriacigeorgica made up the single isolates. Results of DST illustrated that all of the isolates were susceptible to Amikacin, Levofloxacin, Ofloxacin, and Ciprofloxacin, whereas all of them were resistant to Rifampicin and Doxycycline.ConclusionIn conclusion, increasing isolation of actinomycetes found in various clinical cases merits special attention by health authorities in developing countries. In health centers, action should be taken to increase awareness of appropriate diagnostic criteria and management guidelines for actinomycetes diseases. Furthermore, an increase in the number as well as the quality of national and regional reference laboratories may facilitate more accurate diagnosis of actinomycetes diseases.

Project description:BackgroundNon-timber forest products (NTFPs) are important resources for sustenance of rural communities; a systematic planning to manage diverse NTFPs may immensely contribute to food and livelihood security of forest dwellers. Considering this, the present study has been undertaken in the Himachal Pradesh state in north India. It aims to provide detailed information on diversity, distribution, use pattern, and conservation status of selected NTFPs that have market potential, and suggest a possible way for their sustained management and possible role in livelihood upgradation of dependent communities.MethodologyAn inventory of NTFP species was prepared by collecting secondary information from published scientific studies in journals, books, and other periodicals as well as species being traded as per Forest department records. Search on various online databases were also used (Scopus, Google Scholar, PubMed, ISI Web of Science) using specific search terms such as "non-timber forest products," "NTFPs," "medicinal plants," "wild edible plants," and "Himachal Pradesh," "Western Himalaya," and "Northwest Himalaya." A list of potential NTFPs was prepared having market value. To evaluate the relative usefulness of different species, a quantitative valuation was also used by calculating various indices, such as use value (UV), relative frequency of citation (RFC), relative importance index (RI), cultural importance index (CI), and cultural value (CV).ResultsA total of 811 species have been screened that has significant potential for the State, and categorized in 18 groups as per their use. The family use value was highest for Asteraceae (FUV = 76.75). Among plant parts used, whole plants, roots (including rhizomes and tubers), leaves, flowers, fruits, seeds, stems, and barks were used by the forest dwellers. Maximum NTFPs were collected from the warm temperate zone, followed by the temperate, sub-alpine, sub-tropical, and alpine zones. Sixty-one percent of species had medicinal importance, followed by species used for food and fodder purposes. Although species richness of medicinal plants decreased with altitude, however, most plants extracted from high altitudes were high-value species fetching better income. As many as 125 NTFPs were identified under the diverse level of threats according to IUCN criteria and as per the local stakeholders' perceptions.ConclusionHigh dependence on NTFPs by poor and marginal communities for domestic needs as well as market demand of selected species leads to create excessive pressure on them. Unfortunately, the state agencies are not having any robust conservation plan for NTFPs. For long-term management of NTFPs sector, a species-specific conservation strategy, proper harvesting protocol, cultivation practices, the supply of quality planting material, product development and diversification, value chain development, and ensured market is greatly desired. This will not only lead to conserving NTFPs resources in their natural habitats but also lead a sustainable livelihood generation for forest dwellers.

Dataset Information

Microbial diversity of a Himalayan forest and characterization of rare actinomycetes for antimicrobial compounds.

Publications

Microbial diversity of a Himalayan forest and characterization of rare actinomycetes for antimicrobial compounds.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets