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Nearly a decade‐long repeatable seasonal diversity patterns of bacterioplankton communities in the eutrophic Lake Donghu (Wuhan,China) 下载免费PDF全文
Qingyun Yan James C. Stegen Yuhe Yu Ye Deng Xinghao Li Shu Wu Lili Dai Xiang Zhang Jinjin Li Chun Wang Jiajia Ni Xuemei Li Hongjuan Hu Fanshu Xiao Weisong Feng Daliang Ning Zhili He Joy D. Van Nostrand Liyou Wu Jizhong Zhou 《Molecular ecology》2017,26(14):3839-3850
Uncovering which environmental factors govern community diversity patterns and how ecological processes drive community turnover are key questions related to understand the community assembly. However, the ecological mechanisms regulating long‐term variations of bacterioplankton communities in lake ecosystems remain poorly understood. Here we present nearly a decade‐long study of bacterioplankton communities from the eutrophic Lake Donghu (Wuhan, China) using 16S rRNA gene amplicon sequencing with MiSeq platform. We found strong repeatable seasonal diversity patterns in terms of both common (detected in more than 50% samples) and dominant (relative abundance >1%) bacterial taxa turnover. Moreover, community composition tracked the seasonal temperature gradient, indicating that temperature is a key environmental factor controlling observed diversity patterns. Total phosphorus also contributed significantly to the seasonal shifts in bacterioplankton composition. However, any spatial pattern of bacterioplankton communities across the main lake areas within season was overwhelmed by their temporal variabilities. Phylogenetic analysis further indicated that 75%–82% of community turnover was governed by homogeneous selection due to consistent environmental conditions within seasons, suggesting that the microbial communities in Lake Donghu are mainly controlled by niche‐based processes. Therefore, dominant niches available within seasons might be occupied by similar combinations of bacterial taxa with modest dispersal rates throughout different lake areas. 相似文献
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L-色氨酸是芳香族氨基酸的一种,被广泛应用于医药、食品和饲料等领域。大肠杆菌磷酸烯醇式丙酮酸-糖磷酸转移酶系统(PTS系统)在葡萄糖转运和磷酸化过程中起重要作用,是糖代谢基因表达调控的核心。利用Red同源重组系统,构建包含两类典型PTS系统突变(ptsHIcrr~-glf-glk~+和ptsG~-)的L-色氨酸生产菌,并对相关菌株进行补料分批发酵研究。结果表明,不同类型PTS系统突变对菌体生长、L-色氨酸产量、糖酸转化率及副产物生成均有较大影响。与出发菌相比,ptsHIcrr~-glf-glk~+突变株最高OD_(600)达到125,提高47.0%,产酸38.5 g/L,提高25.9%,糖酸转化率16.7%,提高26.5%,乙酸生成略有增加;ptsG~-突变株最高OD_(600)达到100,提高17.6%,产酸33.4 g/L,提高9.4%,糖酸转化率15.5%,提高17.4%,乙酸生成略有减少。对葡萄糖转运系统的进一步研究将为大肠杆菌合成L-色氨酸效率的提升提供帮助。 相似文献
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Lili Jing Shengcui Lin Xiaozhi Wang Jinjin Zhang Meirong Wang Weili Liu Changjun Lv 《Journal of cellular and molecular medicine》2014,18(6):991-1003
Long non‐coding RNAs (lncRNAs) are involved in various pathophysiologic processes and human diseases. However, their dynamics and corresponding functions in pulmonary fibrosis remain poorly understood. In this study, portions of lncRNAs adjacent or homologous to protein‐coding genes were determined by searching the UCSC genome bioinformatics database. This was found to be potentially useful for exploring lncRNA functions in disease progression. Previous studies showed that competing endogenous RNA (ceRNA) hypothesis is another method to predict lncRNA function. However, little is known about the function of ceRNA in pulmonary fibrosis. In this study, we selected two differentially expressed lncRNAs MRAK088388 and MRAK081523 to explore their regulatory mechanisms. MRAK088388 and MRAK081523 were analysed as long‐intergenic non‐coding RNAs (lincRNAs), and identified as orthologues of mouse lncRNAs AK088388 and AK081523, respectively. qRT‐PCR and in situ hybridization (ISH) showed that they were significantly up‐regulated, and located in the cytoplasm of interstitial lung cells. We also showed that MRAK088388 and N4bp2 had the same miRNA response elements (MREs) for miR‐200, miR‐429, miR‐29, and miR‐30, whereas MRAK081523 and Plxna4 had the same MREs for miR‐218, miR‐141, miR‐98, and let‐7. Moreover, the expression levels of N4bp2 and Plxna4 significantly increased in fibrotic rats, and were highly correlated with those of MRAK088388 and MRAK081523, respectively. Among their shared miRNAs, miR‐29b‐3p and let‐7i‐5p decreased in the model group, and were negatively correlated with the expression of MRAK088388 and MRAK081523, respectively. MRAK088388 and MRAK081523 could regulate N4bp2 and Plxna4 expression by sponging miR‐29b‐3p and let‐7i‐5p, respectively, and possessed regulatory functions as ceRNAs. Thus, our study may provide insights into the functional interactions of lncRNA, miRNA and mRNA, and lead to new theories for the pathogenesis and treatment of pulmonary fibrosis. 相似文献
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Yemin Xue Jinjin Yu Xiangfei Song 《Journal of industrial microbiology & biotechnology》2009,36(11):1401-1408
A recombinant Thermotoga maritima β-glucosidase A (BglA) was purified to homogeneity for performing enzymatic hydrolysis of isoflavone glycosides from soy
flour. The kinetic properties K
m, k
cat, and k
cat/K
m of BglA towards isoflavone glycosides, determined using high-performance liquid chromatography, confirmed the higher efficiency
of BglA in hydrolyzing malonylglycosides than non-conjugated glycosides (daidzin and genistin). During hydrolysis of soy flour
by BglA at 80°C, the isoflavone glycosides (soluble form) were extracted from soy flour (solid state) into the solution (liquid
state) in thermal condition and converted to their aglycones (insoluble form), which mostly existed in the pellet to be separated
from BglA in the reaction solution. The enzymatic hydrolysis in one-step and two-step approaches yielded 0.38 and 0.35 mg
genistein and daidzein per gram of soy flour, respectively. The optimum conditions for conversion of isoflavone aglycones
were 100 U per gram of soy flour, substrate concentration 25% (w/v), and incubation time 3 h for 80°C. 相似文献
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油菜叶片总蛋白质双向电泳样品制备方法的改进 总被引:1,自引:0,他引:1
以甘蓝型油菜"扬油6号"的叶片为试验材料,分别采用传统的TCA/Acetone(三氯乙酸/丙酮沉淀法)和改进的PEG(polyethylene glycol)分步提取法提取叶片可溶性总蛋白,并利用条件一致的蛋白质双向电泳体系进行比较。TCA/Acetone法提取的蛋白质双向电泳图谱背景中由于高丰度"housekeeping"结构蛋白的存在,特别是叶片中参与光合作用的Rubisco蛋白的干扰,图谱中低丰度调控蛋白受到了高度覆盖和遮蔽现象,影响双向电泳图谱的质量。而PEG分步提取法提取的蛋白质样品,可以剔除Rubisco蛋白,使获得的双向电泳图谱清晰,无斑点间的遮蔽现象,为油菜叶片蛋白质组定量和定性分析提供了丰富的信息。 相似文献
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Takashi Nishioka Jinjin Guo Daisuke Yamamoto Lihua Chen Petra Huppi Chang Yan Chen 《Journal of cellular biochemistry》2010,109(1):152-161
Cigarette smoking is a mixture of thousands of compounds, many of which are carcinogens, such as NNK [4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone]. Nicotine, as an addictive substance in cigarette, has been shown to promote growth of non‐neuronal cells. It is unclear how nicotine cooperates with tobacco‐related carcinogens during tumorigenesis. Here, by concurrent treatment of nicotine and NNK, we investigate the effect of the cooperation of these two compounds on cell growth and apoptosis in various different lung epithelial (RLE) or cancer (LKR) cells. We demonstrated that short‐term nicotine exposure moderately activated mitogenic signaling pathways (such as PKC, ERK, and Akt) and a mediocre protection against cisplatin‐mediated apoptosis. In contrast, NNK strongly stimulated mitogenic signaling and rendered the cells a high resistance to cisplatin. The pre‐ligation of nAChR by nicotine interfered with NNK‐mediated mitogenic signaling and resistance to cisplatin, the magnitude of which was similar as that exposed to nicotine alone. Interestingly, a week after the exposure to nicotine or nicotine plus NNK, Bcl‐2 expression was augmented, accompanied with the increased resistance to cisplatin‐induced apoptosis. In comparison, long‐term NNK treatment provided very little protection of the cells from cisplatin. We also showed that the combination treatment promoted more cells to grow in an anchorage‐independent fashion than NNK exposure alone. Thus, the data suggest that through occupying nAChR, nicotine appears to modulate NNK‐mediated signaling and persistently sustain pro‐survival activities to promote transformation. J. Cell. Biochem. 109: 152–161, 2010. © 2009 Wiley‐Liss, Inc. 相似文献