Habitat Adaptation Drives Speciation of a Streptomyces Species with Distinct Habitats and Disparate Geographic Origins

Both isolation by distance and isolation by environment occur in bacteria, and different diversification patterns may apply to different species. Streptomyces species, typified by producing useful natural products, are widespread in nature and possess high genetic diversity. However, the ecological processes and evolutionary mechanisms that shape their distribution are not well understood.

Systematic whole-genome sequencing reveals an unexpected diversity among actinomycetoma pathogens and provides insights into their antibacterial susceptibilities

Mycetoma is a neglected tropical chronic granulomatous inflammatory disease of the skin and subcutaneous tissues. More than 70 species with a broad taxonomic diversity have been implicated as agents of mycetoma. Understanding the full range of causative organisms and their antibiotic sensitivity profiles are essential for the appropriate treatment of infections. The present study focuses on the analysis of full genome sequences and antibiotic resistance profiles of actinomycetoma strains from patients seen at the Mycetoma Research Centre in Sudan with a view to developing rapid diagnostic tests. Seventeen pathogenic isolates obtained by surgical biopsies were sequenced using MinION and Illumina methods, and their antibiotic resistance profiles determined. The results highlight an unexpected diversity of actinomycetoma causing pathogens, including three Streptomyces isolates assigned to species not previously associated with human actinomycetoma and one new Streptomyces species. Thus, current approaches for clinical and histopathological classification of mycetoma may need to be updated. The standard treatment for actinomycetoma is a combination of sulfamethoxazole/trimethoprim and amoxicillin/clavulanic acid. Most tested isolates were not susceptible to sulfamethoxazole/trimethoprim or to amoxicillin alone. However, the addition of the β-lactamase inhibitor clavulanic acid to amoxicillin increased susceptibility, particularly for Streptomyces somaliensis and Streptomyces sudanensis . Actinomadura madurae isolates appear to be particularly resistant under laboratory conditions, suggesting that alternative agents, such as amikacin, should be considered for more effective treatment. The results obtained will inform future diagnostic methods for the identification of actinomycetoma and treatment.

Challenges to Explore Genus Streptomyces in Ethiopia-A Mini Review

Genus Streptomyces is gram-positive bacteria that grow in various environments. It has plentiful biotechnological attributes on the area of agricultural, bioremediation, biofuel, clinical, food, industrial, medical, pharmaceutical, and veterinary. The aim of the review is to frontward challenges to explore potent Streptomyces species in the case of Ethiopia. There is lack of the extent and quality of the genetic research regarding to genome sequence, bioactive compound discovery, and genetic manipulation. Their functional and structural diversity is not full studied. To find a new Streptomyces species: Culture media formulation and optimization as wells culture-independent method like Next Generation Sequencing approach should incorporate at national level.

Overexpression of SRO_3163, a homolog of Streptomyces antibiotic regulatory protein, induces the production of novel cyclohexene-containing enamide in Streptomyces rochei

Streptomyces antibiotic regulatory proteins (SARPs) are well characterized as transcriptional activators for secondary metabolites in Streptomyces species. Streptomyces rochei 7434AN4 harbors 15 SARP genes, among which 3 were located on a giant linear plasmid pSLA2-L and others were on the chromosome. Some SARP genes were cloned into an integrative thiostrepton-inducible vector pIJ8600, and their recombinants were cultivated. The recombinant of SARP gene, SRO_3163, accumulated a UV-active compound YM3163-A, which was not detected in the parent strain and other SARP recombinants. Its molecular formula was established to be C8H11NO. Extensive NMR analysis revealed that YM3163-A is a novel enamide, 2-(cyclohex-2-en-1-ylidene)acetamide, and its structure was confirmed by chemical synthesis including Horner-Wadsworth-Emmons reaction and ammonolysis.

Isolation of Novel Vincristine and Vinblastine Producing Streptomyces Species from Catharanthus Roseus Rhizospheric Soil

Microorganisms could be used as efficient tools to protect high value therapeutic plants against overexploitation and climate change. This work aimed to isolate alkaloids producing endophytic and rhizospheric soil actinomycetes and fungi of Catharanthus roseus. From a total of eleven actinomycetes and eight fungi strains isolated by dilution and plate methods, six telluric actinomycetes were revealed to produce alkaloids according to the precipitation test of their extracts. Revelation by Thin Layer Chromatography method using vinblastine and vincristine standards on the basis of frontal reference values showed that the strain SC8 and the vinblastine, the strain SC7 and the vincristine displayed the same frontal references (0,89 and 0,88, respectively). Whole genome sequencing method showed that both strains belong to the genus Streptomyces with novel species.Moreover, metabolic pathways analysis from their genomes allowed to detect three enzymes involved in the biosynthesis of terpenoid backbone leading to that of terpenoid indole alkaloids.