Antimicrobial and antiproliferative prospective of kosinostatin - a secondary metabolite isolated from Streptomyces sp

Genomic Exploration of a Chitinolytic Streptomyces albogriseolus PMB5 Strain from European mantis (Mantis religiosa)

The genus Streptomyces is renowned not only for its natural antibiotic production but also for its abundant chitinolytic enzymes, which break down stubborn chitin into chitooligosaccharides. Despite this, there have been limited studies utilizing whole-genome sequencing to explore the repertoire of chitin degradation and utilization genes in Streptomyces. A particularly compelling source of novel antimicrobials and enzymes lies in the microbiota of insects, where bacterial symbionts produce antimicrobials to protect against opportunistic pathogens and enzymes to adapt to the environment. In this study, we present the chitinolytic strain Streptomyces albogriseolus PMB5, isolated from the insectivorous Mantis religiosa (European mantis). Whole-genome sequencing revealed that PMB5 harbors a linear chromosome of 7,211,961 bp and a linear plasmid of 327,989 bp. The genome comprises 6683 genes, including 6592 protein-coding sequences and 91 RNA genes. Furthermore, genome analysis revealed 19 biosynthetic gene clusters covering polyketides, terpenes, and RiPPs, with 10 clusters showing significant gene similarity (>80%) to known clusters like antimycin, hopene, and geosmin. In the genome of S. albogriseolus PMB5, we were able to identify several antibiotic resistance genes; these included cml (resistance to phenicol), gimA (resistance to macrolides), parY (resistance to aminocoumarin), oleC/oleD (resistance to macrolides), novA (resistance to aminocoumarin) and bla/blc (resistance to beta-lactams). Additionally, three clusters displayed no similarity to known sequences, suggesting novel bioactive compound discovery potential. Remarkably, strain PMB5 is the first reported S. albogriseolus capable of thriving on a medium utilizing chitin as a carbon source, with over 50 chitin-utilizing genes identified, including five AA10 family LPMOs, five GH18 chitinases, and one GH19 chitinase. This study significantly enhances the genomic understanding of S. albogriseolus, a species previously underrepresented in research, paving the way to further exploration of the biotechnological potential of the species.

Redefining bioactive small molecules from microbial metabolites as revolutionary anticancer agents

Cancer treatment remains a significant challenge due to issues such as acquired resistance to conventional therapies and the occurrence of adverse treatment-related toxicities. In recent years, researchers have turned their attention to the microbial world in search of novel and effective drugs to combat this devastating disease. Microbial derived secondary metabolites have proven to be a valuable source of biologically active compounds, which exhibit diverse functions and have demonstrated potential as treatments for various human diseases. The exploration of these compounds has provided valuable insights into their mechanisms of action against cancer cells. In-depth studies have been conducted on clinically established microbial metabolites, unraveling their anticancer properties, and shedding light on their therapeutic potential. This review aims to comprehensively examine the anticancer mechanisms of these established microbial metabolites. Additionally, it highlights the emerging therapies derived from these metabolites, offering a glimpse into the immense potential they hold for anticancer drug discovery. Furthermore, this review delves into approved treatments and major drug candidates currently undergoing clinical trials, focusing on specific molecular targets. It also addresses the challenges and issues encountered in the field of anticancer drug research and development. It also presents a comprehensive exposition of the contemporary panorama concerning microbial metabolites serving as a reservoir for anticancer agents, thereby illuminating their auspicious prospects and the prospect of forthcoming strides in the domain of cancer therapeutics.

Subtercola endophyticus sp. nov., a cold-adapted bacterium isolated from Abies koreana

A novel Gram-stain-positive, aerobic bacterial strain, designated AK-R2A1-2 ^T, was isolated from the surface-sterilized needle leaves of an Abies koreana tree. Strain AK-R2A1-2 ^T had 97.3% and 96.7% 16S rRNA gene sequence similarities with Subtercola boreus K300^T and Subtercola lobariae 9583b^T, respectively, but formed a distinct phyletic lineage from these two strains. Growth of strain AK-R2A1-2 ^T was observed at 4–25 °C at pH 5.0–8.0. Strain AK-R2A1-2 ^T contained menaquinone 9 (MK-9) and menaquinone 10 (MK-10) as the predominant respiratory quinones. The major cellular fatty acids were anteiso-C_15:0 and summed feature 8 (C_18:1ω7c or/and C_18:1ω6c), and the polar lipids included diphosphatidylglycerol (DPG) and three unknown aminolipids, AKL2, AKL3, and AKL4. The complete genome of strain AK-R2A1-2 ^T was sequenced to understand the genetic basis of its survival at low temperatures. Multiple copies of cold-associated genes involved in cold-active chaperon, stress response, and DNA repair supported survival of the strain at low temperatures. Strain AK-R2A1-2 ^T was also able to significantly improve rice seedling growth under low temperatures. Thus, this strain represents a novel species of the genus Subtercola, and the proposed name is Subtercola endophyticus sp. nov. The type strain is AK-R2A1-2 ^T (= KCTC 49721 ^T = GDMCC 1.2921 ^T).

Therapeutic applications and biological activities of bacterial bioactive extracts

Bacteria are rich in a wide variety of secondary metabolites, such as pigments, alkaloids, antibiotics, and others. These bioactive microbial products serve a great application in human and animal health. Their molecular diversity allows these natural products to possess several therapeutic attributes and biological functions. That's why the current natural drug industry focuses on uncovering all the possible ailments and diseases that could be combated by bacterial extracts and their secondary metabolites. In this paper, we review the major utilizations of bacterial natural products for the treatment of cancer, inflammatory diseases, allergies, autoimmune diseases, infections and other diseases that threaten public health. We also elaborate on the identified biological activities of bacterial secondary metabolites including antibacterial, antifungal, antiviral and antioxidant activities all of which are essential nowadays with the emergence of drug-resistant microbial pathogens. Throughout this review, we discuss the possible mechanisms of actions in which bacterial-derived biologically active molecular entities could possess healing properties to inspire the development of new therapeutic agents in academia and industry.

Molecular characterization and antibacterial effect of endophytic actinomycetes Nocardiopsis sp. GRG1 (KT235640) from brown algae against MDR strains of uropathogens

Our study is to evaluate the potential bioactive compound of Nocardiopsis sp. GRG1 (KT235640) and its antibacterial activity against multi drug resistant strains (MDRS) on urinary tract infections (UTIs). Two brown algae samples were collected and were subjected to isolation of endophytic actinomycetes. 100 strains of actinomycetes were isolated from algal samples based on observation of morphology and physiological characters. 40 strains were active in antagonistic activity against various clinical pathogens. Among the strains, 10 showed better antimicrobial activity against MDRS on UTIs. The secondary metabolite of Nocardiopsis sp. GRG1 (KT235640) has showed tremendous antibacterial activity against UTI pathogens compared to other strains. Influence of various growth parameters were used for synthesis of secondary metabolites, such as optimum pH 7, incubation time 5-7 days, temperature (30 °C), salinity (5%), fructose and mannitol as the suitable carbon and nitrogen sources. At 100 μg/ml concentration MIC of Nocardiopsis sp. GRG1 (KT235640) showed highest percentage of inhibition against Proteus mirabilis (85%), and E.coli, Staphylococcus auerues, Psuedomonas aeroginasa, Enterobactor sp and Coagulinase negative staphylococci 78-85% respectively.