Evaluation of antimicrobial and antiproliferative activities of Actinobacteria isolated from the saline lagoons of northwestern Peru

Enhancing Antifungal Drug Discovery Through Co-Culture with Antarctic Streptomyces albidoflavus Strain CBMAI 1855

Fungal infections pose a growing public health threat, creating an urgent clinical need for new antifungals. Natural products (NPs) from organisms in extreme environments are a promising source for novel drugs. Streptomyces albidoflavus CBMAI 1855 exhibited significant potential in this regard. This study aimed to (1) assess the antifungal spectrum of the CBMAI 1855 extract against key human pathogens, (2) elicit NP production through co-cultivation with fungi, correlating the metabolites with the biosynthetic gene clusters (BGCs), and (3) perform in silico toxicity predictions of the identified compounds to analyze their suitability for drug development. The crude extract of CBMAI 1855 exhibited broad-spectrum antifungal activity. The metabolomic analysis identified antifungal NPs such as antimycin A, fungimycin, surugamides, 9-(4-aminophenyl)-3,7-dihydroxy-2,4,6-trimethyl-9-oxo-nonoic acid, and ikarugamycin, with the latter two predicted to be the most suitable for drug development. Genome mining revealed three cryptic BGCs potentially encoding novel antifungals. These BGCs warrant a detailed investigation to elucidate their metabolic products and harness their potential. CBMAI 1855 is a prolific producer of multiple antifungal agents, offering a valuable source for drug discovery. This study highlights the importance of exploring microbial interactions to uncover therapeutics against fungal infections, with a detailed exploration of cryptic BGCs offering a pathway to novel antifungal compounds.

Genomic and physiological characterization of Kitasatospora sp. nov., an actinobacterium with potential for biotechnological application isolated from Cerrado soil

An Actinobacteria - Kitasatospora sp. K002 - was isolated from the soil of Cerrado, a savanna-like Brazilian biome. Herein, we conducted a phylogenetic, phenotypic and physiological characterization, revealing its potential for biotechnological applications. Kitasatospora sp. K002 is an aerobic, non-motile, Gram-positive bacteria that forms grayish-white mycelium on solid cultures and submerged spores with vegetative mycelia on liquid cultures. The strain showed antibacterial activity against Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli. Genomic analysis indicated that Kitasatospora xanthocidica JCM 4862 is the closest strain to K002, with a dDDH of 32.8-37.8% and an ANI of 86.86% and the pangenome investigations identified a high number of rare genes. A total of 60 gene clusters of 22 different types were detected by AntiSMASH, and 22 gene clusters showed low similarity (< 10%) with known compounds, which suggests the potential production of novel bioactive compounds. In addition, phylogenetic analysis and morphophysiological characterization clearly distinguished Kitasatospora sp. K002 from other related species. Therefore, we propose that Kitasatospora sp. K002 should be recognized as a new species of the genus Kitasatospora - Kitasatospora brasiliensis sp. nov. (type strains = K002).

Bioprospecting of unexplored halophilic actinobacteria against human infectious pathogens

Human pathogenic diseases received much attention recently due to their uncontrolled spread of antimicrobial resistance (AMR) which causes several threads every year. Effective alternate antimicrobials are urgently required to combat those disease causing infectious microbes. Halophilic actinobacteria revealed huge potentials and unexplored cultivable/non-cultivable actinobacterial species producing enormous antimicrobials have been proved in several genomics approaches. Potential gene clusters, PKS and NRPKS from Nocardia, Salinospora, Rhodococcus, and Streptomyces have wide range coding genes of secondary metabolites. Biosynthetic pathways identification via various approaches like genome mining, In silico, OSMAC (one strain many compound) analysis provides better identification of knowing the active metabolites using several databases like AMP, APD and CRAMPR, etc. Genome constellations of actinobacteria particularly the prediction of BGCs (Biosynthetic Gene Clusters) to mine the bioactive molecules such as pigments, biosurfactants and few enzymes have been reported for antimicrobial activity. Saltpan, saltlake, lagoon and haloalkali environment exploring potential actinobacterial strains Micromonospora, Kocuria, Pseudonocardia, and Nocardiopsis revealed several acids and ester derivatives with antimicrobial potential. Marine sediments and marine macro organisms have been found as significant population holders of potential actinobacterial strains. Deadly infectious diseases (IDs) including tuberculosis, ventilator-associated pneumonia and Candidiasis, have been targeted by halo-actinobacterial metabolites with promising results. Methicillin resistant Staphylococus aureus and virus like Encephalitic alphaviruses were potentially targeted by halophilic actinobacterial metabolites by the compound Homoseongomycin from sponge associated antinobacterium. In this review, we discuss the potential antimicrobial properties of various biomolecules extracted from the unexplored halophilic actinobacterial strains specifically against human infectious pathogens along with prospective genomic constellations.

Natural products derived from medicinal plants and microbes might act as a game-changer in breast cancer: a comprehensive review of preclinical and clinical studies

Breast cancer (BC) is the most prevalent neoplasm among women. Genetic and environmental factors lead to BC development and on this basis, several preventive - screening and therapeutic interventions have been developed. Hormones, both in the form of endogenous hormonal signaling or hormonal contraceptives, play an important role in BC pathogenesis and progression. On top of these, breast microbiota includes both species with an immunomodulatory activity enhancing the host's response against cancer cells and species producing proinflammatory cytokines associated with BC development. Identification of novel multitargeted therapeutic agents with poly-pharmacological potential is a dire need to combat advanced and metastatic BC. A growing body of research has emphasized the potential of natural compounds derived from medicinal plants and microbial species as complementary BC treatment regimens, including dietary supplements and probiotics. In particular, extracts from plants such as Artemisia monosperma Delile, Origanum dayi Post, Urtica membranacea Poir. ex Savigny, Krameria lappacea (Dombey) Burdet & B.B. Simpson and metabolites extracted from microbes such as Deinococcus radiodurans and Streptomycetes strains as well as probiotics like Bacillus coagulans and Lactobacillus brevis MK05 have exhibited antitumor effects in the form of antiproliferative and cytotoxic activity, increase in tumors' chemosensitivity, antioxidant activity and modulation of BC - associated molecular pathways. Further, bioactive compounds like 3,3'-diindolylmethane, epigallocatechin gallate, genistein, rutin, resveratrol, lycopene, sulforaphane, silibinin, rosmarinic acid, and shikonin are of special interest for the researchers and clinicians because these natural agents have multimodal action and act via multiple ways in managing the BC and most of these agents are regularly available in our food and fruit diets. Evidence from clinical trials suggests that such products had major potential in enhancing the effectiveness of conventional antitumor agents and decreasing their side effects. We here provide a comprehensive review of the therapeutic effects and mechanistic underpinnings of medicinal plants and microbial metabolites in BC management. The future perspectives on the translation of these findings to the personalized treatment of BC are provided and discussed.

Rhizobacterial Isolates from Prosopis limensis Promote the Growth of Raphanus sativus L. Under Salt Stress

Microbial biotechnology employes techniques that rely based on the natural interactions that occur in ecosystems. Bacteria, including rhizobacteria, play an important role in plant growth, providing agricultural crops with an alternative that can mitigate the negative effects of abiotic stress, such as those caused by saline environments. In this study, bacterial isolates were obtained from soil and roots of Prosopis limensis Bentham from the department of Lambayeque, Peru. This region has high salinity levels, therefore, the collected samples were used to isolate plant growth-promoting rhizobacteria (PGPR), which were identified through morphological, and physical-biochemical characteristics. These salt tolerant bacteria were screened phosphate solubilization, indole acetic acid, deaminase activity and molecular characterization by 16S rDNA sequencing. Eighteen samples from saline soils of the Prosopis limensis plants in the northern coastal desert of San Jose district, Lambayeque, Peru. The bacterial isolates were screened for salt tolerance ranging from 2 to 10%, a total of 78 isolates were found. Isolates 03, 13 and 31 showed maximum salt tolerance at 10%, in vitro ACC production, phosphate solubilization and IAA production. The three isolates were identified by sequencing the amplified 16S rRNA gene and were found to be Pseudomonas sp. 03 (MW604823), Pseudomonas sp. 13 (MW604824) and Bordetella sp. 31 (MW604826). These microorganisms promoted the germination of radish plants and increased the germination rates for treatments T2, T3 and T4 by 129, 124 and 118% respectively. The beneficial effects of salt tolerant PGPR isolates isolated from saline environments can be new species, used to overcome the detrimental effects of salt stress on plants. The biochemical response and inoculation of the three isolates prove the potential of using these strains as a source of products that can be employed for the development of new compounds proving their potential as biofertilizers for saline environments.