Development and application of ribosomal engineering in actinomycetes / 生物工程学报

Ribosomal engineering is a technique that can improve the biosynthesis of secondary metabolites in the antibiotics-resistant mutants by attacking the bacterial RNA polymerase or ribosome units using the corresponding antibiotics. Ribosomal engineering can be used to discover and increase the production of valuable bioactive secondary metabolites from almost all actinomycetes strains regardless of their genetic accessibility. As a consequence, ribosomal engineering has been widely applied to genome mining and production optimization of secondary metabolites in actinomycetes. To date, more than a dozen of new molecules were discovered and production of approximately 30 secondary metabolites were enhanced using actinomycetes mutant strains generated by ribosomal engineering. This review summarized the mechanism, development, and protocol of ribosomal engineering, highlighting the application of ribosomal engineering in actinomycetes, with the aim to facilitate future development of ribosomal engineering and discovery of actinomycetes secondary metabolites.

Discovery of a new nosiheptide-producing strain and its fermentation optimization for nosiheptide production / 中国药科大学学报

@#Nosiheptide is a typical thiopeptide antibiotic displaying potent activity toward various drug-resistant strains of Gram-positive pathogens.Although nosiheptide lacks in vivo activity, and good water-solubility with a series of uncontrollable analogues, which may limit its clinical application, glycosylated analogues may overcome problem of low activity and may improve its druggability.In search of novel glycosylated nosiheptide producers, we applied a genome mining strategy that identified Actinoalloteichus sp.AHMU CJ021 that contains all genes required.However, despite the presence of a predicted glycosyltransferase, glycosylated derivatives of nosiheptide were not detected, after following one strain many compounds (OSMAC) strategy and heterologous expression of a regulatory protein NocP.Nevertheless, nosiheptide produced by this strain was remarkably pure, and further experiments were conducted to improve its production by optimization of the culture medium.Under optimal conditions, 58.73 mg/L nosiheptide was produced, representing an almost 6-fold improvement compared to the original fermentation medium.Therefore, we consider Actinoalloteichus sp.AHMU CJ021 a suitable potential candidate for industrial production of nosiheptide, which provides the basis for solving the problem of nosiheptide structural analogues.

Novel angucycline/angucyclinone family of natural products discovered between 2010 and 2020 / 生物工程学报

Angucyclines/angucyclinones are a large group of polycyclic aromatic polyketides and their producers are widely distributed in nature. This family of natural products attracts great attention because of their diverse biological activities and unique chemical structures. With the development of synthetic biology and the exploitation of the actinomycetes from previously unexplored environments, angucyclines/angucyclinones-like natural products with new skeletons were continuously discovered, thus enriching the structural diversity of this family. In this review we summarize the new angucyclines/angucyclinones analogues discovered in the last decade (2010-2020) by using different strategies, such as changing cultivation conditions, genetic modification, genome mining, bioactivity-guided compound isolation, and fermentation of actinomycetes from underexplored environments. We also discuss the role of synthetic biology in the discovery and development of new compounds of the angucycline/angucyclinone family.

Genome mining combined metabolic shunting and OSMAC strategy of an endophytic fungus leads to the production of diverse natural products

Endophytic fungi are promising producers of bioactive small molecules. Bioinformatic analysis of the genome of an endophytic fungus

Genomics approaches decode natural products synthesis / 生物工程学报

Novel natural products have always been the most important sources for discovery of new drugs. Since the end of the 20th century, advances in genomics technology have contributed to decode and analyze numerous genomes, revealing remarkable potential for production of new natural products in organisms. However, this potential is hampered by laboratory culture conditions. Therefore, the integration of all these new advances is necessary to unveil these treasures, addressing the rise in resistance to antibiotics. In this review, we discuss the strategies of genome mining, inducing the expression of silent biosynthetic gene clusters and construction of biological chassis.

Discovery of new antibiotics using genome data mining / 药学学报

With the worldwide spread of multi-drug resistant (MDR) bacteria, bacterial resistance has become a major issue affecting human health. Although traditional methods for obtaining antibiotics by screening bacterial strains have found the most available antibiotics for us, this method has resulted in fewer and fewer antibiotics in the past few decades and is increasingly difficult to find the new structure of the compound entity. At present, there are few drugs that can fight super-resistant bacteria in the clinic or even research. therefore, the development and application of new technologies to address the issue of bacterial resistance is imminent. Since the first bacterial genome was sequenced more than 20 years ago, a large number of bacterial genomic sequence information can provide clues for the discovery of new antibiotics. In this review, we briefly outline the available data sources and highlight the use of genomic mining and metagenomics in discovery of new antibiotics.

Activation of an unconventional meroterpenoid gene cluster in leads to the production of new berkeleyacetals

Fungal genomes carry many gene clusters seemingly capable of natural products biosynthesis, yet most clusters remain cryptic or down-regulated. Genome mining revealed an unconventional paraherquonin-like meroterpenoid biosynthetic gene cluster in the chromosome of . The cryptic or down-regulated pathway was activated by constitutive expression of pathway-specific regulator gene encoded within biosynthetic gene cluster. Chemical analysis of mutant -OE: extracts enabled the isolation of four berkeleyacetal congeners, in which two of them are new. On the basis of careful bioinformatic analysis of the coding enzymes in the gene cluster, the biosynthetic pathway of berkeleyacetals was proposed. These results indicate that this approach would be valuable for discovery of novel natural products and will accelerate the exploitation of prodigious natural products in filamentous fungi.

Epigenetic modification in histone deacetylase deletion strain of leads to diverse diterpenoids

Epigenetic modifications have been proved to be a powerful way to activate silent gene clusters and lead to diverse secondary metabolites in fungi. Previously, inactivation of a histone H3 deacetylase in had led to pleiotropic activation and overexpression of more than 75% of the biosynthetic genes and isolation of ten compounds. Further investigation of the crude extract of strain resulted in the isolation of twelve new diterpenoids including three cassanes (-), one cleistanthane (), six pimaranes (-), and two isopimaranes ( and ) along with two know cleistanthane analogues. Their structures were elucidated by extensive NMR spectroscopic data analysis. Compounds and showed potent inhibitory effects on the expression of MMP1 and MMP2 (matrix metalloproteinases family) in human breast cancer (MCF-7) cells.