Diversity, novelty, antimicrobial activity, and new antibiotics of cultivable endophytic actinobacteria isolated from psammophytes collected from Taklamakan Desert.
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ABSTRACT:
SUBMITTER: Wang T
PROVIDER: S-EPMC8116205 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:We report for the first time the isolation of endophytic actinobacteria associated with wild populations of the Chinese medicinal herb Thymus roseus Schipcz obtained from the arid land in Ili and Tacheng of the Xinjiang Province, China. Strains were isolated by special pretreatment of plant tissues and identified based on their 16S rRNA gene sequences, and their antimicrobial activities in vitro were evaluated. A total of 126 endophytic actinobacteria belonging to two classes, eight orders, 14 families, and 24 genera were isolated from different organs at the Ili and Tacheng sites. In addition, the diversity of culturable endophytic actinobacteria genera was higher at Tacheng site (n = 71, 56.35%) than the Ili site (n = 55, 43.65%). A neighbor-joining tree of 126 isolated actinobacteria showing the phylogenetic relationships based on 16S rRNA gene sequences and the genus Streptomyces was the most dominant isolate. The number of endophytic actinobacteria genera obtained from root tissues (n = 54, 42.86%) was higher compared to stem (n = 35, 27.78%) and leaf tissue (n = 37, 29.36%). Among 126 endophytic actinobacteria, 54 strains were antagonistic against at least one or more indicator organisms in vitro. Notably, most strains of Streptomyces proved antagonistic activities. For example, strain T4SB028, namely Streptomyces polyantibioticus, showed the highest inhibition ratio reached 67.06, 64.20, and 70.55% against Alternaria solani, Valsa malicola, and Valsa mali, respectively. The results demonstrate that about 30.95%, 23.01% of the tested endophytic actinobacteria were capable of producing siderophores and chitinase, respectively. Additionally, the results of the amplification of biosynthetic genes polyketide synthetase (PKS-I) and non-ribosomal peptide synthetase (NRPS) indicated that at least one antibiotic biosynthetic gene was detected in 27 (50%) of the tested strains. Our result emphasizes that the endophytic actinobacteria communities are different based on the plant tissues and the geographical environment of the sampled area. Thus, we conclude that T. roseus Schipcz. provided a rich source of endophytic actinobacteria that exhibited a broad-spectrum antimicrobial agent.
| S-EPMC7080825 | biostudies-literature
Project description:Endophytic actinobacteria are one of the important pharmaceutical resources and well known for producing different types of bioactive substances. Nevertheless, detection of the novelty, diversity, and bioactivity on endophytic actinobacteria isolated from mangrove plants are scarce. In this study, five different mangrove plants, Avicennia marina, Aegiceras corniculatum, Kandelia obovota, Bruguiera gymnorrhiza, and Thespesia populnea, were collected from Beilun Estuary National Nature Reserve in Guangxi Zhuang Autonomous Region, China. A total of 101 endophytic actinobacteria strains were recovered by culture-based approaches. They distributed in 7 orders, 15 families, and 28 genera including Streptomyces, Curtobacterium, Mycobacterium, Micrococcus, Brevibacterium, Kocuria, Nocardioides, Kineococcus, Kytococcus, Marmoricola, Microbacterium, Micromonospora, Actinoplanes, Agrococcus, Amnibacterium, Brachybacterium, Citricoccus, Dermacoccus, Glutamicibacter, Gordonia, Isoptericola, Janibacter, Leucobacter, Nocardia, Nocardiopsis, Pseudokineococcus, Sanguibacter, and Verrucosispora. Among them, seven strains were potentially new species of genera Nocardioides, Streptomyces, Amnibacterium, Marmoricola, and Mycobacterium. Above all, strain 8BXZ-J1 has already been characterized as a new species of the genus Marmoricola. A total of 63 out of 101 strains were chosen to screen antibacterial activities by paper-disk diffusion method and inhibitors of ribosome and DNA biosynthesis by means of a double fluorescent protein reporter. A total of 31 strains exhibited positive results in at least one antibacterial assay. Notably, strain 8BXZ-J1 and three other potential novel species, 7BMP-1, 5BQP-J3, and 1BXZ-J1, all showed antibacterial bioactivity. In addition, 21 strains showed inhibitory activities against at least one "ESKAPE" resistant pathogens. We also found that Streptomyces strains 2BBP-J2 and 1BBP-1 produce bioactive compound with inhibitory activity on protein biosynthesis as result of translation stalling. Meanwhile, Streptomyces strain 3BQP-1 produces bioactive compound inducing SOS-response due to DNA damage. In conclusion, this study proved mangrove plants harbored a high diversity of cultivable endophytic actinobacteria, which can be a promising source for discovery of novel species and bioactive compounds.
| S-EPMC5945994 | biostudies-literature
Project description:Deserts, as an unexplored extreme ecosystem, are known to harbor diverse actinobacteria with biotechnological potential. Both multidrug-resistant (MDR) pathogens and environmental issues have sharply raised the emerging demand for functional actinobacteria. From 2000 to 2021, 129 new species have been continuously reported from 35 deserts worldwide. The two largest numbers are of the members of the genera Streptomyces and Geodermatophilus, followed by other functional extremophilic strains such as alkaliphiles, halotolerant species, thermophiles, and psychrotolerant species. Improved isolation strategies for the recovery of culturable and unculturable desert actinobacteria are crucial for the exploration of their diversity and offer a better understanding of their survival mechanisms under extreme environmental stresses. The main bioprospecting processes involve isolation of target actinobacteria on selective media and incubation and selection of representatives from isolation plates for further investigations. Bioactive compounds obtained from desert actinobacteria are being continuously explored for their biotechnological potential, especially in medicine. To date, there are more than 50 novel compounds discovered from these gifted actinobacteria with potential antimicrobial activities, including anti-MDR pathogens and anti-inflammatory, antivirus, antifungal, antiallergic, antibacterial, antitumor, and cytotoxic activities. A range of plant growth-promoting abilities of the desert actinobacteria inspired great interest in their agricultural potential. In addition, several degradative, oxidative, and other functional enzymes from desert strains can be applied in the industry and the environment. This review aims to provide a comprehensive overview of desert environments as a remarkable source of diverse actinobacteria while such rich diversity offers an underexplored resource for biotechnological exploitations.
| S-EPMC8696123 | biostudies-literature
Project description:Saxaul (Haloxylon ammodendron) is the most widespread plant community in the Gobi Desert in Mongolia, which plays important roles in wind control, sand fixation and water conservation. Investigations of soil-derived actinobacteria inhabiting in the saxaul forest in Gobi Desert in Mongolia have been scarce. In this study, biodiversity of culturable actinobacteria isolated from soil of the saxaul forest in Southern Gobi Aimak (Southern Gobi Province) of Mongolia was characterized and their potential to produce compounds with antibacterial activities was assessed. A total of 172 actinobacterial strains were recovered by culture-based approaches and were phylogenetically affiliated into 22 genera in 13 families of seven orders. Forty-nine actinobacterial isolates were selected to evaluate the antibacterial activities and their underlying mechanism of action was screened by means of a dual-fluorescent reporter assay (pDualrep2). Twenty-three isolates exhibited antagonistic activity against at least one of the tested pathogens, of which two Streptomyces strains can attenuate protein translation by ribosome stalling. Combinational strategies based on modern metabolomics, including bioassay-guided thin-layer chromatography (TLC), UPLC-QTOF-MS/MS based structural annotation and enhanced molecular networking successfully annotated chloramphenicol, althiomycin and granaticin and their derivatives as the antibacterial compounds from extracts in three Streptomyces strains, respectively. This work demonstrates that UPLC-MS/MS-based structural identification and enhanced molecular networking are effective strategies to rapidly illuminate the bioactive chemicals in the microbial extracts. Meanwhile, our results show that the saxaul forest in Mongolia Gobi Desert is a prospective source for discovering novel actinobacteria and biologically active compounds.
| S-EPMC9147431 | biostudies-literature
Project description:Mangrove is a rich and underexploited ecosystem with great microbial diversity for discovery of novel and chemically diverse antimicrobial compounds. The goal of the study was to explore the pharmaceutical actinobacterial resources from mangrove soil and gain insight into the diversity and novelty of cultivable actinobacteria. Consequently, 10 mangrove soil samples were collected from Futian and Maoweihai of China, and the culture-dependent method was employed to obtain actinobacteria. A total of 539 cultivable actinobacteria were isolated and distributed in 39 genera affiliated to 18 families of 8 orders by comparison analysis of partial 16S rRNA gene sequences. The dominant genus was Streptomyces (16.0 %), followed by Microbacterium (14.5 %), Agromyces (14.3 %), and Rhodococcus (11.9 %). Other 35 rare actinobacterial genera accounted for minor proportions. Notably, 11 strains showed relatively low 16S rRNA gene sequence similarities (< 98.65 %) with validly described species. Based on genotypic analyses and phenotypic characteristics, 115 out of the 539 actinobacterial strains were chosen as representative strains to test their antibacterial activities against "ESKAPE" bacteria by agar well diffusion method and antibacterial mechanism by the double fluorescent protein reporter system. Fifty-four strains in 23 genera, including 2 potential new species, displayed antagonistic activity in antibacterial assay. Meanwhile, 5 strains in 3 genera exhibited inhibitory activity on protein biosynthesis due to ribosome stalling. These results demonstrate that cultivable actinobacteria from mangrove soil are potentially rich sources for discovery of new antibacterial metabolites and new actinobacterial taxa.
| S-EPMC6590530 | biostudies-literature
Project description:The aim of this study was to isolate and identify Actinobacteria from Malaysia mangrove forest and screen them for production of antimicrobial secondary metabolites. Eighty-seven isolates were isolated from soil samples collected at 4 different sites. This is the first report to describe the isolation of Streptomyces, Mycobacterium, Leifsonia, Microbacterium, Sinomonas, Nocardia, Terrabacter, Streptacidiphilus, Micromonospora, Gordonia, and Nocardioides from mangrove in east coast of Malaysia. Of 87 isolates, at least 5 isolates are considered as putative novel taxa. Nine Streptomyces sp. isolates were producing potent antimicrobial secondary metabolites, indicating that Streptomyces isolates are providing high quality metabolites for drug discovery purposes. The discovery of a novel species, Streptomyces pluripotens sp. nov. MUSC 135(T) that produced potent secondary metabolites inhibiting the growth of MRSA, had provided promising metabolites for drug discovery research. The biosynthetic potential of 87 isolates was investigated by the detection of polyketide synthetase (PKS) and nonribosomal polyketide synthetase (NRPS) genes, the hallmarks of secondary metabolites production. Results showed that many isolates were positive for PKS-I (19.5%), PKS-II (42.5%), and NRPS (5.7%) genes, indicating that mangrove Actinobacteria have significant biosynthetic potential. Our results highlighted that mangrove environment represented a rich reservoir for isolation of Actinobacteria, which are potential sources for discovery of antimicrobial secondary metabolites.
| S-EPMC4138949 | biostudies-literature
Project description:Actinobacteria are wide spread in nature and represent the largest taxonomic group within the domain Bacteria. They are abundant in soil and have been extensively explored for their therapeutic applications. This versatile group of bacteria has adapted to diverse ecological habitats, which has drawn considerable attention of the scientific community in recent times as it has opened up new possibilities for novel metabolites that may help in solving some of the most challenging problems of the day, for example, novel drugs for drug-resistant human pathogens, affordable means to maintain ecological balance in various habitats, and alternative practices for sustainable agriculture. Traditionally, free dwelling soil actinobacteria have been the subject of intensive research. Of late, symbiotic actinobacteria residing as endophytes within the plant tissues have generated immense interest as potential source of novel compounds, which may find applications in medicine, agriculture, and environment. In the light of these possibilities, this review focuses on the diversity of endophytic actinobacteria isolated from the plants of extreme habitats and specific ecological niches. Furthermore, an attempt has been made to assign chemical class to the compounds obtained from endophytic actinobacteria. Potential therapeutic applications of these compounds and the utility of endophytic actinobacteria in agriculture and environment are discussed.
| S-EPMC6092505 | biostudies-other
Project description:Grapevine trunk diseases (GTDs) are a significant problem for New Zealand viticulture. Endophytic actinobacteria are of interest as potential biocontrol agents due to their ability to inhibit plant pathogens and improve plant growth. However, no studies have investigated the diversity of actinobacteria associated with grapevines in New Zealand vineyards and their bioactivity. Actinobacteria diversity in different 'Sauvignon blanc' vine tissues from three vineyards (conventional and organic management, and different vine ages) was assessed using different methods and media. Forty-six endophytic actinobacteria were isolated, with more isolates recovered from roots (n = 45) than leaves (n = 1) and shoot internodes (n = 0). More isolates were recovered from the organic (n = 21) than conventional (n = 8) vineyard, mature (25-year old; n = 21) than young (2-year old; n = 2) vines and using a tissue maceration technique (n = 40). Actinomycete Isolation Agar, International Streptomyces Project 2, and Starch Casein media were effective for actinobacteria isolation. Most of the isolates recovered belonged to Streptomyces, with one isolate identified as Mycolicibacterium. Forty isolates were assessed for antifungal activity and plant growth-promoting (PGP) characteristics. Of these, 13 isolates had antifungal activity against test GTD pathogens (Dactylonectria macrodidyma, Eutypa lata, Ilyonectria liriodendri, Neofusicoccum parvum, and N. luteum). Eighteen isolates exhibited more than one PGP trait; 25siderophore production (n = 25), phosphate solubilization (n = 6), and indole acetic acid production (n = 16). Two strains, Streptomyces sp. LUVPK-22 and Streptomyces sp. LUVPK-30, exhibited the best antifungal and PGP properties. This study revealed the diversity of culturable endophytic actinobacteria from grapevines in New Zealand vineyards and their biocontrol potential against GTD pathogens.
| S-EPMC9633489 | biostudies-literature
Project description:The phylogenetic diversity of cultivable actinobacteria isolated from sponges (Haliclona spp.) and associated intertidal zone environments along the northern parts of the western coast of India were studied using 16S rRNA gene sequences. A subset of randomly selected actinobacterial cultures were screened for three activities, namely predatory behaviour, antibacterial activity and enzyme inhibition. We recovered 237 isolates from the phylum Actinobacteria belonging to 19 families and 28 genera, which could be attributed to 95 putative species using maximum-likelihood partition and 100 putative species using Bayesian partition in Poisson tree processes. Although the trends in the discovery of actinobacterial genera isolated from sponges were consistent with previous studies from different study areas, we provide the first report of nine actinobacterial species from sponges. We observed widespread non-obligate epibiotic predatory behaviour in eight actinobacterial genera and we provide the first report of predatory activity in Brevibacterium , Glutamicibacter , Micromonospora , Nocardiopsis , Rhodococcus and Rothia . Sponge-associated actinobacteria showed significantly more predatory behaviour than environmental isolates. While antibacterial activity by actinobacterial isolates mainly affected Gram-positive target bacteria with little or no effect on Gram-negative bacteria, predation targeted both Gram-positive and Gram-negative prey with equal propensity. Actinobacterial isolates from both sponges and associated environments produced inhibitors of serine proteases and angiotensin-converting enzyme. Predatory behaviour was strongly associated with inhibition of trypsin and chymotrypsin. Our study suggests that the sponges and associated environments of the western coast of India are rich in actinobacterial diversity, with widespread predatory activity, antibacterial activity and production of enzyme inhibitors. Understanding the diversity and associations among various actinobacterial activities - with each other and the source of isolation - can provide new insights into marine microbial ecology and provide opportunities to isolate novel therapeutic agents.
| S-EPMC8549387 | biostudies-literature
Project description:Bamboos, regarded as therapeutic agents in ethnomedicine, have been used to inhibit inflammation and enhance natural immunity for a long time in Asia, and there are many bamboo associated fungi with medical and edible value. In the present study, a total of 350 fungal strains were isolated from the uncommon moso bamboo (Phyllostachys edulis) seeds for the first time. The molecular diversity of these endophytic fungi was investigated and bioactive compound producers were screened for the first time. All the fungal endophytes were categorized into 69 morphotypes according to culturable characteristics and their internal transcriber spacer (ITS) regions were analyzed by BLAST search with the NCBI database. The fungal isolates showed high diversity and were divided in Ascomycota (98.0%) and Basidiomycota (2.0%), including at least 19 genera in nine orders. Four particular genera were considered to be newly recorded bambusicolous fungi, including Leptosphaerulina, Simplicillium, Sebacina and an unknown genus in Basidiomycetes. Furthermore, inhibitory effects against clinical pathogens and phytopathogens were screened preliminarily and strains B09 (Cladosporium sp.), B34 (Curvularia sp.), B35 (undefined genus 1), B38 (Penicillium sp.) and zzz816 (Shiraia sp.) displayed broad-spectrum activity against clinical bacteria and yeasts by the agar diffusion method. The crude extracts of isolates B09, B34, B35, B38 and zzz816 under submerged fermentation, also demonstrated various levels of bioactivities against bambusicolous pathogenic fungi. This study is the first report on the antimicrobial activity of endophytic fungi associated with moso bamboo seeds, and the results show that they could be exploited as a potential source of bioactive compounds and plant defense activators. In addition, it is the first time that strains of Shiraia sp. have been isolated and cultured from moso bamboo seeds, and one of them (zzz816) could produce hypocrellin A at high yield, which is significantly different from the other strains published.
| S-EPMC3997407 | biostudies-literature