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111.
以大鼠再生肝为材料成功克隆到肝再生相关基因MafF的开放阅读框(ORF).该ORF全长471 bp,编码由157个氨基酸组成的蛋白质.基因芯片研究表明,MafF 基因在部分肝切除后表达水平迅速升高.为了研究该基因在肝再生进程中的作用,构建其真核表达载体pEGFP-N1-MafF,在肝再生模型中进行融合表达.结果表明,转... 相似文献
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Production of conjugated linoleic acids through KOH-catalyzed dehydration of ricinoleic acid 总被引:8,自引:0,他引:8
Production of conjugated linoleic acids (CLA) using castor oil as starting material involves conversion of ricinoleic acid to methyl 12-mesyloxy-octadec-9-enoate (MMOE) followed by dehydration. This process usually uses 1,8-diazabicyclo-(5.4.0)-undec-7-ene (DBU) as an expensive dehydrating reagent. The present study reports that potassium hydroxide (KOH) can serve as a dehydrating reagent in replacement of DBU. The results showed that conversion of MMOE to CLA catalyzed by KOH was an efficient reaction, with a 77% conversion efficiency at 80 degrees C. The CLA isomeric profile produced in KOH-catalyzed dehydration reaction was similar to that catalyzed by DBU. The CLA mixture produced in KOH-catalyzed dehydration of MMOE at 80 degrees C contained 72% 9c,11t-18:2 and 26% 9c,11c-18:2 while in that catalyzed by DBU, 9c,11t-18:2 and 9c,11c-18:2 accounted for 78 and 16%, respectively. It was found that the temperature of dehydration was an important factor in the determination of CLA isomer composition and yield of conversion. Elevating the temperature from 78 to 180 degrees C decreased not only the conversion efficiency but also production of total c,t-18:2 and c,c-18:2 isomers regardless of dehydration catalyzed by either DBU or KOH. It is concluded that KOH may replace DBU as a dehydrating reagent in conversion of MMOE to CLA when the reaction conditions are optimized. 相似文献
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Knockout of the adp gene related with colonization in Bacillus nematocida B16 using customized transcription activator‐like effectors nucleases 下载免费PDF全文
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Background
In plants, 14-3-3 proteins are encoded by a large multigene family and are involved in signaling pathways to regulate plant development and protection from stress. Although twelve Populus 14-3-3s were identified based on the Populus trichocarpa genome V1.1 in a previous study, no systematic analysis including genome organization, gene structure, duplication relationship, evolutionary analysis and expression compendium has been conducted in Populus based on the latest P. trichocarpa genome V3.0.Principal Findings
Here, a comprehensive analysis of Populus 14-3-3 family is presented. Two new 14-3-3 genes were identified based on the latest P. trichocarpa genome. In P. trichocarpa, fourteen 14-3-3 genes were grouped into ε and non-ε group. Exon-intron organizations of Populus 14-3-3s are highly conserved within the same group. Genomic organization analysis indicated that purifying selection plays a pivotal role in the retention and maintenance of Populus 14-3-3 family. Protein conformational analysis indicated that Populus 14-3-3 consists of a bundle of nine α-helices (α1-α9); the first four are essential for formation of the dimer, while α3, α5, α7, and α9 form a conserved peptide-binding groove. In addition, α1, α3, α5, α7, and α9 were evolving at a lower rate, while α2, α4, and α6 were evolving at a relatively faster rate. Microarray analyses showed that most Populus 14-3-3s are differentially expressed across tissues and upon exposure to various stresses.Conclusions
The gene structures and their coding protein structures of Populus 14-3-3s are highly conserved among group members, suggesting that members of the same group might also have conserved functions. Microarray and qRT-PCR analyses showed that most Populus 14-3-3s were differentially expressed in various tissues and were induced by various stresses. Our investigation provided a better understanding of the complexity of the 14-3-3 gene family in poplars. 相似文献117.
《Acta Oecologica》2007,31(3):419-425
Semi-natural grassland communities are of great interest in conservation because of their high species richness. These communities are being threatened by both land abandonment and nitrogen eutrophication, and their continued existence will depend upon correct management. However, there is a distinct lack of studies of the ecological mechanisms that regulate species diversity and productivity in Mediterranean grasslands. We have conducted a 3-year field experiment in a species-poor grassland in central Italy to investigate the effects of nitrogen fertilization coupled with removal of plant litter and artificial cutting on species diversity and community productivity. Vegetation cutting reduced living biomass but increased species diversity. In fact, cutting had positive effects on the cover of almost all of the annual and biennial species, while it had a negative effect on the dominant perennial grasses Brachypodium rupestre and Dactylis glomerata. Litter removal had similar effects to cutting, although it was far less effective in increasing species diversity. In contrast, nitrogen enrichment strongly increased the living biomass while maintaining very low species diversity. Our results have indicated that semi-natural Mediterranean grasslands need specific management regimes for maintenance and restoration of species diversity. In the management of these grasslands, attention should be paid to the potential threat from nitrogen enrichment, especially when coupled with land abandonment. 相似文献
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Lei Dong Hong Ming Yi-Rui Yin Yan-Yan Duan En-Min Zhou Guo-Xing Nie Hui-Geng Feng Lan Liu Wen-Jun Li 《Antonie van Leeuwenhoek》2014,105(5):899-905
An alkalitolerant, thermotolerant and Gram-stain negative bacterium, designated strain YIM 78007T, was isolated from an alkaline geothermal soil sample from Hehua hot spring, Tengchong, Yunnan province, south-west China. Cells of strain YIM 78007T were observed to be aerobic and short rod-shaped. The colonies were observed to be orange-red, convex and circular. 16S rRNA gene sequence-based phylogenetic analysis showed that strain YIM 78007T clustered with members of the genus Roseomonas (with similarities from 97.2 to 92.2 %). Optimal growth of strain YIM 78007 occurs at 40–50 °C and pH 8.0–10.0. The predominant ubiquinone was identified as Q-10 and the major fatty acids were identified as C18:1 ω7c and C16:0. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminolipids and one unknown phospholipid. The G + C content of the genomic DNA was determined to be 63 mol %. The levels of DNA–DNA hybridization relatedness between strain YIM 78007T and its closet neighbours (Roseomonas lacus JCM 13283T and Roseomonas terrae JCM 14592T) were well below the threshold required for the proposal of a novel species. The results of physiological and biochemical characteristics, the phylogenetic analysis, as well as low DNA–DNA hybridization values, allowed the phenotypic and genotypic differentiation of strain YIM 78007T from its closest phylogenetic neighbours. Therefore, strain YIM 78007T is considered to represent a novel species of the genus Roseomonas, for which the name Roseomonas alkaliterrae sp. nov. is proposed. The type strain is YIM 78007T (=BCRC 80644T = JCM 19656T). 相似文献
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