Zunyimycins B and C, New Chloroanthrabenzoxocinones Antibiotics against Methicillin-Resistant Staphylococcus aureus and Enterococci from Streptomyces sp. FJS31-2.

This study performed an optimization of the fermentation conditions to activate the expression of the zunyimycin family biosynthesis genes of the zunyimycin-producing streptomycetes strain Streptomyces sp. FJS31-2. Bioassay-guided isolation and purification by varied chromatographic methods yielded two new compounds of the zunyimycin derivatives, namely, 31-2-7 and 31-2-8, accompanied with three known anthrabenzoxocinones family members of zunyimycin A, BE24566B, and chloroanthrabenzoxocinone. Their structures were elucidated by NMR, HRESIMS, IR, UV, and CD. Results showed that these two compounds were structurally similar to the previously reported compound zunyimycin A but differed in positions and number of chlorine atom substitution. The two novel compounds were called zunyimycins B and C. Antibacterial activity assay indicated that zunyimycin C showed a good inhibitory effect on the methicillin-resistant Staphylococcus aureus and Enterococci.

Molecular Genetic Characterization of an Anthrabenzoxocinones Gene Cluster in Streptomyces Sp. FJS31-2 for the Biosynthesis of BE-24566B and Zunyimycin Ale.

Genome mining is an effective tool used to discover novel natural products from actinomycetes. Genome sequence analysis of Streptomyces sp. FJS31-2 revealed the presence of one putative type II polyketide gene cluster (ABX), which may correspond to type II polyketide products including BE-24566B and its chloro-derivatives. The addition of natural humus acid successfully activated the biosynthsis of the abx gene cluster. BE-24566B and its chloro-derivatives, named zunyimycin A, were also detected. The targeted deletion of the polyketide skeleton synthesis genes such as abxp, abxk, and abxs was performed in the wild strain to identify the gene cluster for BE-24566B biosynthesis.

Tandem expression in E. coli of type III PKS and P450 genes from marine Streptomyces olivaceus FXJ 7.023 gives production of phenol and indole.

The draft genome sequence of marine Streptomyces olivaceus strain FXJ 7.023 contains a cryptic Type III polyketide synthase (type III PKS) gene cluster, which is similar to the Streptomyces coelicolor THN biosynthesis gene cluster. A putative type III PKS (SoRppA) gene and its adjacent gene for cytochrome P450 158A2 (SoCYP158A2) of this gene cluster were cloned by PCR screening through a fosmid genomic library of S. olivaceus FXJ 7.023. Tandem expression of SoRppA and SoCYP158A2 in Escherichia coli strain BL21 (DE3) plysS resulted in obvious biosynthesis of phenol and indole, while heterologous expression of SoRppA or SoCYP158A2 alone did not. The engineered strain sorppAcyp158a2BL21 showed tolerance to phenol concentration up to 0.75 g/L. Continuous biosynthesis of phenol and indole by the immobilized engineered strain on macroporousresin was achieved, and the productivities of phenol and indole in extractant-free culture in 102 h were 0.08 and 1.525 g/L/h, respectively, with the highest production reached 0.67 and 14.48 g/L, respectively. These results suggest that the engineered strain and immobilized continuous fermentation process may provide potential for "green" production of phenol and indole.

Knowledge graph analysis and visualization of AI technology applied in COVID-19.

With the global outbreak of coronavirus disease (COVID-19) all over the world, artificial intelligence (AI) technology is widely used in COVID-19 and has become a hot topic. In recent 2 years, the application of AI technology in COVID-19 has developed rapidly, and more than 100 relevant papers are published every month. In this paper, we combined with the bibliometric and visual knowledge map analysis, used the WOS database as the sample data source, and applied VOSviewer and CiteSpace analysis tools to carry out multi-dimensional statistical analysis and visual analysis about 1903 pieces of literature of recent 2 years (by the end of July this year). The data is analyzed by several terms with the main annual article and citation count, major publication sources, institutions and countries, their contribution and collaboration, etc. Since last year, the research on the COVID-19 has sharply increased; especially the corresponding research fields combined with the AI technology are expanding, such as medicine, management, economics, and informatics. The China and USA are the most prolific countries in AI applied in COVID-19, which have made a significant contribution to AI applied in COVID-19, as the high-level international collaboration of countries and institutions is increasing and more impactful. Moreover, we widely studied the issues: detection, surveillance, risk prediction, therapeutic research, virus modeling, and analysis of COVID-19. Finally, we put forward perspective challenges and limits to the application of AI in the COVID-19 for researchers and practitioners to facilitate future research on AI applied in COVID-19.