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971.
Xiaohui Zhang Sihai Yang Jiao Wang Yanxiao Jia Ju Huang Shengjun Tan Yan Zhong Ling Wang Longjiang Gu Jian‐Qun Chen Qinghua Pan Joy Bergelson Dacheng Tian 《The Plant journal : for cell and molecular biology》2015,84(1):20-28
Plant resistance genes (R genes) harbor tremendous allelic diversity, constituting a robust immune system effective against microbial pathogens. Nevertheless, few functional R genes have been identified for even the best‐studied pathosystems. Does this limited repertoire reflect specificity, with most R genes having been defeated by former pests, or do plants harbor a rich diversity of functional R genes, the composite behavior of which is yet to be characterized? Here, we survey 332 NBS‐LRR genes cloned from five resistant Oryza sativa (rice) cultivars for their ability to confer recognition of 12 rice blast isolates when transformed into susceptible cultivars. Our survey reveals that 48.5% of the 132 NBS‐LRR loci tested contain functional rice blast R genes, with most R genes deriving from multi‐copy clades containing especially diversified loci. Each R gene recognized, on average, 2.42 of the 12 isolates screened. The abundant R genes identified in resistant genomes provide extraordinary redundancy in the ability of host genotypes to recognize particular isolates. If the same is true for other pathogens, many extant NBS‐LRR genes retain functionality. Our success at identifying rice blast R genes also validates a highly efficient cloning and screening strategy. 相似文献
972.
不同来源甜高粱种质资源的表型遗传多样性分析 总被引:1,自引:0,他引:1
通过对主要农艺性状的方差分析及聚类分析,对194份不同来源的甜高粱种质资源进行了表型性状的遗传多样性分析。结果表明,不同来源品种间的性状差异较大,与中国品种相比,国外品种具有植株高大、生物产量高及含糖量高等优异性状,可用于国内资源的种质创新及品种改良。遗传距离为0.66时将所有资源划分为6类,各类群主要按农艺性状进行了划分。研究结果将为杂交育种的亲本选择提供理论参考。 相似文献
973.
Ruanhong Cai Mingsheng Lu Yaowei Fang Yuliang Jiao Qiang Zhu Zhaopu Liu Shujun Wang 《Annals of microbiology》2014,64(1):147-155
A psychrotolerant dextranase-producing bacterium was isolated from the Gaogong island seacoast near Jiangsu, China. The bacterium, denoted as DP03, was identified as Catenovulum sp. based on its phenotype, biochemical characteristics, and 16S rRNA gene comparison. The optimal enzyme production time, initial pH, temperature, and aeration conditions of strain DP03 were found to be 28 h, 8.0, 30 °C, and 25 % volume of liquid in 100-ml Erlenmeyer flasks, respectively. The ability of 1 % dextran T20 to induce dextranase was investigated. Dextranase from strain DP03 displayed its maximum activity at pH 8.0 and 40 °C and was found to be stable at 30 °C and over a broad range of pH values (pH 6–11). Scanning electron microscopy showed that dextranase from the isolate DP03 could at least partially prevent Streptococcus mutans from forming biofilms on glass coverslips. 相似文献
974.
Chuan-Xin Zhang Wei Cui Min Zhang Jie Zhang Tian-Yang Wang Jiang Zhu Guang-Zhong Jiao Jing-He Tan 《PloS one》2014,9(4)
We studied the role of the Na+/Ca2+ exchanger (NCX) in modulating oocyte postovulatory aging by observing changes in NCX contents and activities in aging mouse and rat oocytes. Whereas the NCX activity was measured by observing oocyte activation following culture with NCX inhibitor or activator, the NCX contents were determined by immunohistochemical quantification. Although NCX was active in freshly-ovulated rat oocytes recovered 13 h post hCG injection and in aged oocytes recovered 19 h post hCG in both species, it was not active in freshly-ovulated mouse oocytes. However, NCX became active when the freshly-ovulated mouse oocytes were activated with ethanol before culture. Measurement of cytoplasmic Ca2+ revealed Ca2+ increases always before NCX activation. Whereas levels of the reactive oxygen species (ROS) and the activation susceptibility increased, the density of NCX member 1 (NCX1) decreased significantly with oocyte aging in both species. While culture with H2O2 decreased the density of NCX1 significantly, culture with NaCl supplementation sustained the NCX1 density in mouse oocytes. It was concluded that (a) the NCX activity was involved in the modulation of oocyte aging and spontaneous activation; (b) ROS and Na+ regulated the NCX activity in aging oocytes by altering its density as well as functioning; and (c) cytoplasmic Ca2+ elevation was essential for NCX activation in the oocyte. 相似文献
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977.
Zhi‐Kai Guo Rui‐Hua Jiao Hao‐Fu Dai Wen‐Li Mei Ren‐Xiang Tan Hui‐Ming Ge 《化学与生物多样性》2013,10(2):296-302
An isolate of rare actinobacteria strain Amycolatopsis sp. HCa1 obtained from the gut of grasshopper produced seven different metabolites in vitro. The metabolites isolated from its mycelia cakes were characterized by NMR and MS analyses. Actinotetraose hexatiglate (or tigloside; 1 ) with nonreducing glucotetraose skeleton was isolated as a major constituent; three new tetrasaccharide derivatives actinotetraoses I–K ( 2 – 4 , resp.) and three known actinotetraoses A–C ( 5 – 7 , resp.) were also isolated. 相似文献
978.
Weiqiang Zhou Menghao Cai Jiushun Zhou Tao Jiang Jiao Zhou Meixia Wang Xiangshan Zhou Yuanxing Zhang 《Journal of industrial microbiology & biotechnology》2013,40(10):1131-1142
An integrated nutrition and bioprocess strategy was developed for improving the biosynthesis of an antitumor compound, 1403C, by a marine-derived fungus, Halorosellinia sp. (no. 1403). First, statistical design strategies were synthetically applied to optimize the nutritional composition. The resulting 1403C production reached 2.07 g/l, which was 143.5 % higher than the original production. However, it only produced 0.44 g/l of 1403C in 5-l bioreactor fermentation. Thus, the operating parameters including culture pH, dissolved oxygen, agitation speed, impeller type and inoculum level were considered to improve the fermentation process, and an effective control strategy for 1403C production by Halorosellinia sp. submerged in a 5-l bioreactor was established. When inoculating 0.22 g/l dry biomass, controlling dissolved oxygen not lower than 30 % during the growth phase but ranging between 30 and 40 % during the stationary phase, using a double-layer six-flat-blade Rushton disc turbine agitated at 400 rpm, keeping short-term low pH and rapid-rising pH with glucose starvation, the highest 1403C production was finally obtained at 1.32 g/l, which was promoted by 200 % compared to before optimization. Fermentation scale-up was finally performed in a 500-l bioreactor, and 1403C production of 1.09 g/l was obtained. 相似文献
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980.