Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Identification of a Novel Streptomyces chattanoogensis L10 and Enhancing Its Natamycin Production by Overexpressing Positive Regulator ScnRII: Yi-Ling Du , Shi-Fei Chen , Liang-Ying Cheng , Xue-Ling Shen , Yuan Tian , Yong-Quan Li; J. Microbiol. 2009;47(4):506-513. Published online September 9, 2009; DOI: https://doi.org/10.1007/s12275-009-0014-0

Abstract: A novel Streptomyces strain, L10, which is capable of producing natamycin, was isolated from a soil sample collected from Zhejiang province, China. On the basis of phylogenetic analysis of rpoB gene and 16S rDNA sequences, as well as phenotypic comparison, strain L10 (CGMCC 2644) is proposed to be a previously uncharacterized strain of S. chattanoogensis. By screening a cosmid library of strain L10 and primer walking, a partial sequence of scnRI and the entire sequence of scnRII were obtained, which are orthologues to the pathway-specific positive regulator genes of natamycin biosynthesis in S. natalensis. The engineered S. chattanoogensis D1, generated by inserting an additional copy of scnRII into the chromosome of strain L10, increased its natamycin production by 3.3 fold in YSG medium and 4.6 fold in YEME medium without sucrose.

Cloning and Sequence Analysis of a Glyceraldehyde-3-phosphate Dehydrogenase Gene from Ganoderma lucidum: Xu Fei , Ming Wen Zhao , Yu Xiang Li; J. Microbiol. 2006;44(5):515-522.; DOI: https://doi.org/2446 [pii]

Abstract: A cDNA library of Ganoderma lucidum has been constructed using a Zap Express cloning vector. A glyceraldehyde-3-phosphate dehydrogenase gene (gpd) was isolated from this library by hybridization of the recombinant phage clones with a gpd-specific gene probe generated by PCR. By comparison of the cDNA and the genomic DNA sequences, it was found that the complete nucleotide sequence encodes a putative polypeptide chain of 338 amino acids interrupted by 6 introns. The predicted amino acid sequence of this gene shows a high degree of sequence similarity to the GPD proteins from yeast and filamentous fungi. The promoter region contains a CT-rich stretch, two CAAT boxes, and a consensus TATA box. The possibility of using the gpd promoter in the construction of new transformation vectors is discussed.

Strain Improvement of Candida tropicalis for the Production of Xylitol:Biochemical and Physiological Characterization of Wild-type and Mutant Strain CT-OMV5: Ravella Sreenivas Rao , Cherukuri Pavana Jyothi , Reddy Shetty Prakasham , Chaganti Subba Rao , Ponnupalli Nageshwara Sarma , Linga Venkateswar Rao; J. Microbiol. 2006;44(1):113-120.; DOI: https://doi.org/2328 [pii]

Abstract: Candida tropicalis was treated with ultraviolet (UV) rays, and the mutants obtained were screened for xylitol production. One of the mutants, the UV1 produced 0.81g of xylitol per gram of xylose. This was further mutated with N-methyl-N’-nitro-N-nitrosoguanidine (MNNG), and the mutants obtained were screened for xylitol production. One of the mutants (CT-OMV5) produced 0.85g/g of xylitol from xylose. Xylitol production improved to 0.87 g/g of xylose with this strain when the production medium was supplemented with urea. The CT-OMV5 mutant strain differs by 12 tests when compared to the wild-type Candida tropicalis strain. The XR activity was higher in mutant CT-OMV5. The distinct difference between the mutant and wild-type strain is the presence of numerous chlamydospores in the mutant. In this investigation, we have demonstrated that mutagenesis was successful in generating a superior xylitol-producing strain, CT-OMV5, and uncovered distinctive biochemical and physiological characteristics of the wild-type and mutant strain, CT-OMV5.

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