Genomic and Metabolomic Profiling of Streptomyces anulatus 89: Molecular Phylogeny and Biosynthesis of Antitumor Antibiotics

Integrated experimental and computational characterization of bioactive metabolites from Streptomyces paradoxus GH53 with antimicrobial, antioxidant, and antitumor activities

Streptomyces species are widely recognized as valuable sources of secondary metabolites with diverse biological activities. In this study, the isolate GH53 was identified as Streptomyces paradoxus based on morphological characteristics and partial 16 S rRNA gene sequence analysis. Fermentation conditions were optimized to enhance metabolite production, and the crude ethyl acetate extract was chemically characterized using GC-MS, FT-IR, and UV-Vis spectroscopy. The analytical profile suggested the presence of a chemically complex mixture containing fatty acids, fatty acid derivatives, hydrocarbons, and terpenoid-related constituents. The IC₅₀ values of the crude extract were 0.175 ± 0.013 and 0.097 ± 0.006 mg/mL for the DPPH and ABTS radical scavenging assays, respectively. Because the calculated DPPH IC₅₀ value was slightly below the lowest tested concentration, it should be interpreted as a fitted estimate derived from the dose–response curve rather than as a directly measured concentration point. It also showed cytotoxic activity against HePG-2 and MCF-7 cell lines, with IC₅₀ values of 19.50 ± 1.5 and 28.81 ± 2.0 µg/mL, respectively. To provide a preliminary molecular interpretation of these extract-level bioactivities, selected representative metabolites tentatively identified by GC-MS were evaluated individually as defined ligands using molecular docking, molecular dynamics simulation, and ADMET prediction. The modeled compounds showed favorable predicted interactions with selected antimicrobial-, antioxidant-, and anticancer-related protein targets, and the corresponding protein–ligand complexes generally maintained stable interaction profiles during simulation. However, ADMET analysis indicated potential limitations for some high-molecular-weight lipophilic constituents, including poor drug-likeness, limited predicted solubility, and possible toxicity liabilities. Overall, these findings suggest that S. paradoxus GH53 represents a promising source of bioactive metabolites for future fractionation, purification, structural confirmation, and compound-level biological evaluation. The results should be interpreted as preliminary screening evidence and not as confirmation of therapeutic efficacy or direct systemic drug suitability.

Screening of Actinomycetes from Rhizosphere Soils for L-glutaminase Production

Actinomycetes are filamentous, Gram-positive bacteria of major ecological and biomedical importance due to their exceptional ability to produce diverse bioactive secondary metabolites encoded by numerous biosynthetic gene clusters. In the present study, actinomycetes were isolated from rhizospheric and non-rhizospheric soil samples and systematically characterized using morphological, biochemical, and molecular approaches. The isolates were screened for antimicrobial, antioxidant, and L-glutaminase-producing potential, followed by 16S rRNA gene sequencing for taxonomic identification. Several isolates exhibited strong antibacterial activity against clinically significant pathogens, including Staphylococcus aureus (NCIM 2073) and Escherichia coli (NCTC 9001). Antioxidant potential evaluated using the DPPH radical scavenging assay confirmed the presence of redox-active metabolites. Efficient production of L-glutaminase, an amidohydrolase enzyme was observed. To complement the experimental findings, in silico molecular docking studies were performed to investigate the interaction of selected bioactive compounds with relevant target proteins, providing mechanistic insights into binding affinity and molecular stability. The docking results revealed favourable binding energies and key hydrogen-bond and hydrophobic interactions, supporting the observed biological activities. Overall, the integrated experimental and in silico approach highlights soil-derived actinomycetes as versatile and sustainable bioresources with significant pharmaceutical and biotechnological potential, emphasizing their role in combating antimicrobial resistance and enabling the rational development of novel therapeutic and industrial products.

Metabologenomic approach to discover aromatic polyketides, angucycline antimicrobial compounds produced by alkaliphilic Streptomyces.

Streptomyces spp. is renowned for their capacity to produce structurally diverse secondary metabolites with potent bioactivities, including antimicrobial, antitumor, and antioxidant properties. In the present study, an alkaliphilic strain, designated as Streptomyces S9, was isolated and taxonomically characterised through multilocus sequence analysis (MLSA) using Streptomyces-specific primers. Extracted metabolites exhibited antimicrobial activity against Fusarium sp., Aspergillus sp., Corynespora sp., Bacillus sp., Staphylococcus aureus, Pseudomonas sp., and E. coli. Genomic DNA from strain S9 was subjected to PCR-based screening to detect biosynthetic gene clusters (BGCs) including nonribosomal peptide synthetase (NRPS), type I and type II polyketide synthase (PKS I and PKS II), and monooxygenase genes involved in the synthesis of natural products. Targeted amplification revealed the presence of PKS II and monooxygenase gene fragments, indicating its genetic potential to biosynthesise aromatic polyketides. Bioactive secondary metabolites were extracted from the culture supernatant, fractionated using preparative thin-layer chromatography (TLC), and subsequently analysed using liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Bioactivity-guided fractionation identified two active fractions (AA2 and AA3) with bactericidal and fungicidal activity. LC-HRMS/MS analysis tentatively indicated two high-molecular-weight metabolites with [M + H]+ ion peaks at m/z 1355 and 1342, whose fragmentation patterns are analogous to glycosylated angucycline-type scaffolds, pending full structural confirmation by NMR spectroscopy.

Isolation, Genomic Characterization and Biotechnological Potential of Culturable Bacteria from Metal-Rich and Organic Soils of La Soledad Dam, Guanajuato, Mexico

Findings highlight the potential biotechnological relevance of culturable bacterial isolates recovered from historically mining-impacted soils and provide genomic resources for future studies on environmental remediation, sustainable agriculture, and industrial biotechnology.

Genome mining and comparative genome analysis of Pseudomonas fluorescens revealed diverse biosynthetic and metabolic potential

Understanding of the metabolic capabilities and genomic landscape of the P. fluorescens species is enhanced, providing a foundation for natural product discovery using bioinformatic approaches.

Genomic insights into the bioremediation potential of Paenibacillus taichungensis strain 53b: a multi-resistant plant growth-promoting bacterium