Multi-omic characterisation of Streptomyces hygroscopicus NRRL 30439: detailed assessment of its secondary metabolic potential

The emergence of multidrug-resistant pathogenic bacteria creates a demand for novel antibiotics with distinct mechanisms of action. Advances in next-generation genome sequencing promised a paradigm shift in the quest to...

Endophytic Streptomyces hygroscopicus OsiSh-2-Mediated Balancing between Growth and Disease Resistance in Host Rice

Under disease stress, activation of defense response in plants often comes with the cost of a reduction in growth and yield, which is referred as the growth-defense trade-off. The microorganisms which can be recruited by plants to mitigate the growth-defense trade-off are of great value in crop breeding.

PHÂN LẬP VÀ TUYỂN CHỌN CÁC CHỦNG XẠ KHUẨN CÓ KHẢ NĂNG SINH ENZYME NGOẠI BÀO, ĐỐI KHÁNG VIBRIO SPP.

Nghiên cứu được tiến hành nhằm phân lập và tuyển chọn các chủng xạ khuẩn từ các ao nuôi tôm thẻ chân trắng ở huyện Thạnh Phú, tỉnh Bến Tre có khả năng sinh enzyme ngoại bào và đối kháng với Vibrio spp. Có tất cả 26 chủng xạ khuẩn được phân lập, trong đó 5 chủng TM1, TM2, TM7, TM21 và TM22 được xác định đều là các chủng đa chức năng. Cả 5 chủng này đều có khả năng sản sinh tốt cả 3 loại enzyme protease, amylase và cellulase. Đặc biệt, 3 chủng TM1, TM2 và TM21 còn có khả năng đối kháng với Vibrio spp.. Phân tích kết quả giải trình tự gen 16S rRNA cho thấy cả 3 chủng TM1, TM2, TM21 đều thuộc loài Streptomyces hygroscopicus. Hai chủng TM7 và TM22 được xác định lần lượt là Streptomyces diastaticus và Streptomyces spiralis.

In vitro Test for Inhibition of Plasmodium falciparum 3D7 Parasites using Streptomyces hygroscopicus subsp. hygroscopicus Strain i18, Isolated from a Pineapple Farm in Lampung

Increasing natural ingredient awareness and utilization has created an increased demand for sources of natural medicinal ingredients, including sources of compound used to treat malaria. Streptomyces is a genus of prokaryote well recognized for its production of antibiotics and other pharmaceutically useful compound. This study aimed to assess the ability of unpurified fermentation metabolites to inhibit Plasmodium parasites. A strain of bacteria identified as Streptomyces hygroscopicus subsp. hygroscopicus strain i18 were isolated from pineapple fields in Lampung province, and was cultured and fermented on liquid synthetic Gause medium for 10 days. The supernatant was separated from the cells and extracted with ethyl acetate-methanol (1:1). Plasmodium falciparum 3D7 was used for antiplasmodial testing. Metabolites were tested qualitatively using a phytochemical approach. Saponins and triterpenoids were found to be present in the extract. Parasite inhibition as measured using probit analysis and yielded an IC50 value of 11.07 g.m/L. These findings suggest further examinations of this extract (e.g. assessment of off-target effects) are warranted.

Increasing the Ascomycin Yield by Relieving the Inhibition of Acetyl/Propionyl-CoA Carboxylase by the Signal Transduction Protein GlnB

Ascomycin (FK520) is a multifunctional antibiotic produced by Streptomyces hygroscopicus var. ascomyceticus. In this study, we demonstrated that the inactivation of GlnB, a signal transduction protein belonging to the PII family, can increase the production of ascomycin by strengthening the supply of the precursors malonyl-CoA and methylmalonyl-CoA, which are produced by acetyl-CoA carboxylase and propionyl-CoA carboxylase, respectively. Bioinformatics analysis showed that Streptomyces hygroscopicus var. ascomyceticus contains two PII family signal transduction proteins, GlnB and GlnK. Protein co-precipitation experiments demonstrated that GlnB protein could bind to the α subunit of acetyl-CoA carboxylase, and this binding could be disassociated by a sufficient concentration of 2-oxoglutarate. Coupled enzyme activity assays further revealed that the interaction between GlnB protein and the α subunit inhibited both the activity of acetyl-CoA carboxylase and propionyl-CoA carboxylase, and this inhibition could be relieved by 2-oxoglutarate in a concentration-dependent manner. Because GlnK protein can act redundantly to maintain metabolic homeostasis under the control of the global nitrogen regulator GlnR, the deletion of GlnB protein enhanced the supply of malonyl-CoA and methylmalonyl-CoA by restoring the activity of acetyl-CoA carboxylase and propionyl-CoA carboxylase, thereby improving the production of ascomycin to 390 ± 10 mg/L. On this basis, the co-overexpression of the β and ε subunits of propionyl-CoA carboxylase further increased the ascomycin yield to 550 ± 20 mg/L, which was 1.9-fold higher than that of the parent strain FS35 (287 ± 9 mg/L). Taken together, this study provides a novel strategy to increase the production of ascomycin, providing a reference for improving the yield of other antibiotics.