Phylogenomic analysis of type I polyketide synthase genes in pathogenic and saprobic ascomycetes

Type II thioesterases were shown to maintain efficiency of modular type I polyketide synthases and nonribosomal peptide synthetases by removing acyl residues blocking extension modules. We found that thioesterase ScoT from Streptomyces coelicolor A3(2) is required for the production of the yellow-pigmented coelimycin by the modular polyketide synthase Cpk. No production of coelimycin was observed in cultures of scoT disruption mutant. Polyketide production was restored upon complementation with an intact copy of the scoT gene. An enzymatic assay showed that ScoT thioesterase can hydrolyse a 12-carbon acyl chain but the activity is too low to play a role in product release from the polyketide synthase. We conclude that ScoT is an editing enzyme necessary to maintain the activity of polyketide synthase Cpk. We provide a HPLC based method to measure the amount of coelimycin P2 in a culture medium.

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Classification and characterization of endophytic actinomycetes isolated from cinnamomum cassia presl

Vietnam Journal of Biotechnology ◽

10.15625/1811-4989/16/1/13459 ◽

2018 ◽

Vol 16 (1) ◽

pp. 149-155

Author(s):

Vu Thi Hanh Nguyen ◽

Chu Ky Son ◽

Phi Quyet Tien

Keyword(s):

Polyketide Synthase ◽

Biologically Active ◽

Health Concern ◽

Rrna Gene ◽

Type I ◽

Endophytic Actinomycetes ◽

Cinnamomum Cassia ◽

Antibiotic Synthesis ◽

Medical Plants ◽

Cinnamomum Cassia Presl

Currently, antibiotic resistance in pathogenic bacteria is a significant clinical problem with the increase of deseases and a serious public health concern. Thus, the identification of new antimicrobial agents, especially the secondary metabolites products by endophytic actinobacteria from medical plants could be promising sources of biologically active compounds in medical fields. This study focused on identification and evaluation of antimicrobial activity against pathogens; genes involved in their secondary metabolisms, and screening of anthracycline producing capacity (mainly presented in anti-cancer antibiotics) of YBQ75 isolated from Cinnamomum cassia Presl. plants in Yen Bai province. Based on manual of bacterial classification, method in International Streptomyces Project (ISP) and the 16S rRNA gene sequence (GenBank Acc. No. KR814822), the endophytic actinomycetes YBQ75 was named Streptomyces cavourensis YBQ75 with 100% identity. The strain S. cavourensis YBQ75 showed the remarkable antibacterial activities against 5 tested pathogens (Salmonella enterica ATCC 14028 (22.0 mm); Pseudomonas aeruginosa CNLM (19.3 mm); Staphylococcus epidermidis ATCC 12228 (19.3 mm); Enterobacter aerogenes ATCC 13048 (17.7 mm) and Proteus vulgaris CNLM (16.3 mm)) in the total of 9 tested pathogens. The detection of genes involved in antibiotic synthesis indicated that the strain S. cavourensis YBQ75 consists of all three genes related to antibiotic synthesis including polyketide synthase (pks-I) type I, polyketide synthase type II (pks-II) and nonribosomal peptide synthetase (nrps). Premarilly result showed that the strain S. cavourensis YBQ75 also present as an anthracycline productive actinomycetes. The resutls demonstrated that the endophytic actinomycetes S. cavourensis YBQ75 from medical plants could be promising sources for the production of antibiotics and anthracycline anticancer compounds.

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Molecular Identification of Selected Streptomyces Strains Isolated from Mexican Tropical Soils and their Anti-Candida Activity

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16111913 ◽

2019 ◽

Vol 16 (11) ◽

pp. 1913

Author(s):

Diana Escalante-Réndiz ◽

Susana de-la-Rosa-García ◽

Raúl Tapia-Tussell ◽

Jesús Martín ◽

Fernando Reyes ◽

...

Keyword(s):

Antifungal Activity ◽

Polyketide Synthase ◽

Inhibitory Concentration ◽

Ethanol Extract ◽

Tropical Soils ◽

Antifungal Compound ◽

Type I ◽

Antimicrobial Compounds ◽

Organic Extract ◽

Streptomyces Genus

The increasing incidence of Candida albicans infections and resistance to current antifungal therapies has led to the search for new and more effective antifungal compounds. Actinobacterial species from the Streptomyces genus are recognized as some of the major producers of antimicrobial compounds. Therefore, the aims of this study were: (1) the identification of Streptomyces strains isolated from Mexican tropical acidic soils, (2) the evaluation of their antifungal activity on C. albicans, and (3) the exploration of the presence of polyketide synthase genes in their genome and antifungal secondary metabolites in their extracts. Four actinobacterial strains, isolated from previously unexplored soils with antibacterial antecedents, were selected. These strains were identified as Streptomyces angustmyceticus S6A-03, Streptomyces manipurensis S3A-05 and S3A-09, and Streptomyces parvisporogenes S2A-04, according to their molecular analyses. The ethanol extract of the lyophilized supernatant of S. parvisporogenes displayed the most interesting antifungal activity against C. albicans, with a minimum inhibitory concentration (MIC) of 0.5 mg/mL. Type I polyketide synthase (PKS-I) and non-ribosomal peptide synthase (NRPS) genes were detected in all strains. In addition, type II PKS genes (PKS-II) were also found in S. manipurensis S3A-05 and S. parvisporogenes. LC-UV-HRMS analysis of the active organic extract of S. parvisporogenes indicated the presence of the known antifungal compound carbazomycin G as the major component.

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