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Anqiu Liu,Bing Liu,Zehui Zhang,Zhongfeng Fang,Kecheng Huang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4
In this study, we have developed a new method for the synthesis of EMF from HMF and fructose using mesoporous MCM-41 supported 12-tungstophosphoric acid (MCM-41-HPW) as the catalyst. The structure of 40 wt.% MCM-41-HPW was characterized by various techniques and its surface acidity was determined by potentiometric titration. A high EMF yield of 83.4% was obtained from HMF by the etherification reaction. Synthesis of EMF from fructose was also realized through one-pot reaction with a moderate yield of 42.9%. More importantly, the catalyst could be reused for several times without the loss of its catalytic activity.
( Yanyan Liu ),( Hojin Ryu ),( Beibei Ge ),( Guohui Pan ),( Lei Sun ),( Kyungseok Park ),( Kecheng Zhang ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.12
Wuyiencin is produced by Streptomyces ahygroscopicus var. wuyiensis CK-15 and is widely used as an antifungal agent in agriculture. Analysis of wuyiencin biosynthetic gene clusters reveals wysR, a member of the LAL-family of transcriptional regulatory genes. WysR consists of an Nterminal PAS domain and a LuxR family C-terminal helix-turn-helix motif. However, the roles of wysR in wuyiencin biosynthesis are largely unknown. In this study, we showed that inactivation of wysR resulted in the complete loss of wuyiencin production, which could be restored by complementation with a single copy of wysR. Furthermore, we successfully increased wuyiencin production to a significantly higher level by overexpression of wysR in S. wuyiensis CK-15. Quantitative real-time RT-PCR analysis showed that WysR regulates wuyiencin biosynthesis by modulating other putative regulatory genes. Thus, WysR was identified as an activator of wuyiencin biosynthesis, and overexpression of wysR gene proved to be an effective strategy for improving wuyiencin production.
( Kotnala Balaraju ),( Chang Jin Kim ),( Dong Jin Park ),( Ki Woong Nam ),( Kecheng Zhang ),( Mee Kyung Sang ),( Kyungseok Park ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.9
This is the first report that paromomycin, an antibiotic derived from Streptomyces sp. AG-P 1441 (AG-P 1441), controlled Phytophthora blight and soft rot diseases caused by Phytophthora capsici and Pectobacterium carotovorum, respectively, in chili pepper (Capsicum annum L.). Chili pepper plants treated with paromomycin by foliar spray or soil drenching 7 days prior to inoculation with P. capsici zoospores showed significant (p < 0.05) reduction in disease severity (%) when compared with untreated control plants. The disease severity of Phytophthora blight was recorded as 8% and 50% for foliar spray and soil drench, respectively, at 1.0 ppm of paromomycin, compared with untreated control, where disease severity was 83% and 100% by foliar spray and soil drench, respectively. A greater reduction of soft rot lesion areas per leaf disk was observed in treated plants using paromomycin (1.0 μg/ml) by infiltration or soil drench in comparison with untreated control plants. Paromomycin treatment did not negatively affect the growth of chili pepper. Furthermore, the treatment slightly promoted growth; this growth was supported by increased chlorophyll content in paromomycin-treated chili pepper plants. Additionally, paromomycin likely induced resistance as confirmed by the expression of pathogenesis-related (PR) genes: PR-1, β-1,3-glucanase, chitinase, PR-4, peroxidase, and PR-10, which enhanced plant defense against P. capsici in chili pepper. This finding indicates that AG-P 1441 plays a role in pathogen resistance upon the activation of defense genes, by secretion of the plant resistance elicitor, paromomycin.