Two new strains of Streptomyces with metabolic potential for biological control of pear black spot disease.

Background: Pear black spot is caused by Alternaria tenuissima. It is one of the diseases of concern limiting pear production worldwide. Existing cultivation methods and fungicides are not sufficient to control early blight.

A quantitative analytical method for valienone and its application in the evaluation of valienone production by a breakthrough microbial process.

Valienone is a significant natural carbasugar member of the C7-cyclitol family as a valuable precursor for glycosidase inhibitor drugs. It is an intermediate of validamycin A biosynthesis pathway and exhibits minimal accumulation in the fermentation broth of the natural Streptomyces producer. A quantitative analytical method is crucial for the development of a breakthrough microbial process overcoming the consumption of the natural metabolic flux.

Research advances on microbial genetics in China in 2015.

In 2015, there are significant progresses in many aspects of the microbial genetics in China. To showcase the contribution of Chinese scientists in microbial genetics, this review surveys several notable progresses in microbial genetics made largely by Chinese scientists, and some key findings are highlighted. For the basic microbial genetics, the components, structures and functions of many macromolecule complexes involved in gene expression regulation have been elucidated.

Gamma-butyrolactone regulatory system of Streptomyces chattanoogensis links nutrient utilization, metabolism, and development.

Gamma-butyrolactones (GBLs) produced by several Streptomyces species have been shown to serve as quorum-sensing signaling molecules for activating antibiotic production. The GBL system of Streptomyces chattanoogensis L10, a producer of antifungal agent natamycin, consists of three genes: scgA, scgX, and scgR. Both scgA and scgX contribute to GBL production, while scgR encodes a GBL receptor.

A new antitumour ansamitocin from Actinosynnema pretiosum.

A new compound of ansamitocin was isolated from the extracts of fermentation medium of mutant strain HGF052 derived from Actinosynnema pretiosum ssp. aurantium ATCC 31565, and identified as N-demethyl-desepoxy-9-methoxy-maytansinol (1) on the basis of extensive spectroscopic methods. Bioassay results showed that compound 1 had cytotoxic activity against HL-60 and BEL-7402 cell lines.

[Construction of efficient conjugal plasmids between Escherichia coli and Streptomycetes].

Conjugal plasmid pGH112 has been developed based on the replicons of Streptomyces coelicolor plasmid SCP2 and E. coli ColE. The plasmid contains ampicilin resistance gene(amp) for selection in E.