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41.
根据柑橘黄龙病亚洲种23S/5S的DNA序列设计一对引物对不同地理来源的6个柑橘黄龙病样品DNA进行扩增,扩增片段大小均为1 654 bp包括一个假定细胞壁水解酶假基因(putative cell wall hydrolase pseudogene)和5S rRNA 基因.序列同源性分析结果表明;6个柑橘黄龙病病原菌样品与柑橘黄龙病病原菌亚洲种Sihui样品的同源性为99%,然而与土壤杆菌,布鲁氏菌,根瘤菌,中华根瘤菌,巴通体菌和中慢生根瘤菌的同源性只有89%~95%,说明在23S/5S rDNA序列上黄龙病病原菌亚洲种与α变形菌纲根瘤菌目的其他病原菌相差较大.对黄龙病病原菌亚洲种种内的23S/5S rDNA序列进行比较分析,结果发现黄龙病病原菌亚洲种种内之间putative cell wall hydrolase pseudogene和5S rRNA的基因序列非常保守,但不同地理来源的柑橘黄龙病样品碱基序列间确实存在差异,差异的大小与地理的远近无关.利用简约法对黄龙病病原菌亚洲种及α变形菌纲其它病原菌的23S/5S rDNA序列构建的系统发育树显示黄龙病病原菌亚洲种单独聚为一类,其他细菌聚为另一类,该结果与基于rplJ基因及16S rRNA基因的DNA序列构建的分子系统进化树结果一致. 相似文献
42.
Bohong Liao Lingrong Peng Jin Zhou Huiting Mo Jialan Zhao Zike Yang Xiaowen Guo Peiquan Zhang Xin Zhang Zhibo Zhu 《化学与生物多样性》2019,16(5)
Human nasopharyngeal carcinoma is a common head and neck malignancy with high incidence in Southeast Asia and Southern China. It is necessary to develop safe, effective and inexpensive anticancer agents to improve the therapeutics of patients with nasopharyngeal carcinoma. A series of small molecular compounds based on 6‐(pyrimidin‐4‐yl)‐1H‐indazole were synthesized and evaluated for antiproliferative activities against human nasopharyngeal carcinoma cell lines SUNE1. Compounds 6b , 6c , 6e and 6l showed potent antiproliferative activities similar to positive control drug cisplatin in vitro with lower nephrotoxicity than it. N‐[4‐(1H‐Indazol‐6‐yl)pyrimidin‐2‐yl]benzene‐1,3‐diamine ( 6l ) was selected for further study. It was found that 6l induced mitochondria‐mediated apoptosis and G2/M phase arrest in SUNE1 cells. Furthermore, compound 6l at 10 mg/kg can suppress the growth of an implanted SUNE1 xenograft with a TGI% (tumor growth inhibition) value of 50 % and did not cause serious side effects in BALB/c nude mice. This study suggests that 6‐(pyrimidin‐4‐yl)‐1H‐indazole derivatives are a series of small molecule compounds with anti‐nasopharyngeal carcinoma activities. 相似文献
43.
Hong-Feng Gu Hai-Zhe Li Ya-Ling Tang Xiao-Qing Tang Xi-Long Zheng Duan-Fang Liao 《PloS one》2016,11(4)
Our previous studies have indicated that a novel curcumin derivate nicotinate-curcumin (NC) has beneficial effects on the prevention of atherosclerosis, but the precise mechanisms are not fully understood. Given that autophagy regulates lipid metabolism, the present study was designed to investigate whether NC decreases foam cell formation through restoring autophagy flux in oxidized low-density lipoprotein (ox-LDL)-treated THP-1 cells. Our results showed that ox-LDL (100 μg/ml) was accumulated in THP-1 cells and impaired autophagy flux. Ox-LDL-induced impairment of autophagy was enhanced by treatment with the autophagy inhibitor chloroquine (CQ) and rescued by the autophagy inducer rapamycin. The aggregation of ox-LDL was increased by CQ, but decreased by rapamycin. In addition, colocalization of lipid droplets with LC3-II was remarkably reduced in ox-LDL group. In contrast, NC (10 μM) rescued the impaired autophagy flux by significantly increasing level of LC3-II, the number of autophagolysosomes, and the degradation of p62 in ox-LDL-treated THP-1 cells. Inhibition of the PI3K-Akt-mTOR signaling was required for NC-rescued autophagy flux. Notably, our results showed that NC remarkably promoted the colocalization of lipid droplets with autophagolysosomes, increased efflux of cholesterol, and reduced ox-LDL accumulation in THP-1 cells. However, treatment with 3-methyladenine (3-MA) or CQ reduced the protective effects of NC on lipid accumulation. Collectively, the findings suggest that NC decreases lipid accumulation in THP-1 cells through restoring autophagy flux, and further implicate that NC may be a potential therapeutic reagent to reverse atherosclerosis. 相似文献
44.
2000a间,中国境内野生稻分布区域由2495575km2缩减至1371094km2,减少了45.06%;分布纬度北界由38°3′N南移至28°14′N,南移9°49′、1140km;中国境内栽培稻分布区域由4081860km2增加至9600000km2,增加了135.00%;分布北界由38°N北移至53°29′N,北移15°29′、1700km。人口分布重心主要在黄河流域和长江流域,对该区域野生稻的生存产生不利影响。而促进栽培稻的发展,必须建立野生稻自然保护区。 相似文献
45.
Pingqing Fu Fengchang Wu Cong-Qiang Liu Zhongqing Wei Yingchen Bai Haiqing Liao 《Biogeochemistry》2006,81(2):179-189
Dissolved organic matter (DOM) in sediment porewaters from Lake Erhai, Southwest China was investigated using dissolved organic carbon (DOC) concentration, UV absorbance, fluorescence and molecular weight distribution. DOC exhibited a high concentration at the sediment–water interface with a rapid decrease to the oxic–anoxic interface at approximately 7 cm, and then increased with depth. Similar trends were also found for the UV absorption coefficients at 254 and 280 nm in the porewaters. DNA in the sediment was also measured, which confirmed the high abundance of aerobic bacteria in the upper layer of the sediment. Both humic-like (peaks A and C) and protein-like (peaks B and D) fluorescence were observed in the porewater DOM, and their fluorescence intensities exhibited a similar porewater profile as DOC concentration. A strong correlation was found between the peak fluorescence intensity ratio r(A, C) and r(D, B). Both the fluorescence index and UV absorption coefficient at 254 nm suggested a dramatic increase in aromaticity of porewater DOM across the oxic–anoxic interface. Porewater DOM exhibited a multimodal distribution of molecular weight with a relatively low polydispersity. The results of this study offer significant insight into the nature and properties of DOM in freshwater ecosystems. 相似文献
46.
【目的】本研究旨在克隆来自北极海洋、具有合成卤化物潜力的链霉菌(Streptomyces sp.)604F中的一个卤化酶基因,为后续克隆卤化物合成基因簇、分离鉴定卤化物提供指导。【方法】利用琼脂块法初步测试抗菌活性,借助液相色谱-飞行时间串联质谱技术(LC-Tof MS)初步寻找Streptomyces sp.604F发酵粗提液中的卤化物,并以简并PCR扩增合成次级代谢产物的指示基因(I型、II型聚酮合酶及非核糖体多肽合成酶编码基因);根据依赖黄素腺嘌呤二核苷酸的卤化酶基因保守区设计的简并引物,扩增基因片段并测序分析;采用高效热不对称交错PCR(hiTAIL-PCR)技术扩增卤化酶基因全长。【结果】Streptomyces sp.604F具有较强的抗白色念珠菌活性,其基因组同时含有编码I型聚酮合酶、II型聚酮合酶和非核糖体多肽合成酶基因,以及卤化酶基因;通过染色体步移克隆该卤化酶基因全长,共1443 bp,编码一个新的非色氨酸卤化酶,在合成已知卤化物的卤化酶数据库中,与其同源关系最近的为一类参与合成糖肽类次级代谢产物的卤化酶。【结论】Streptomyces sp.604F具有新的非色氨酸卤化酶,且推测参与糖肽类化合物的卤化修饰,为后续寻找目的卤化物提供了指导,也为研究该合成基因簇奠定基础。 相似文献
47.
Combinatorial signals of activin/nodal and bone morphogenic protein regulate the early lineage segregation of human embryonic stem cells 总被引:2,自引:0,他引:2
Wu Z Zhang W Chen G Cheng L Liao J Jia N Gao Y Dai H Yuan J Cheng L Xiao L 《The Journal of biological chemistry》2008,283(36):24991-25002
Cell fate commitment of pre-implantation blastocysts, to either the inner cell mass or trophoblast, is the first step in cell lineage segregation of the developing human embryo. However, the intercellular signals that control fate determination of these cells remain obscure. Human embryonic stem cells (hESCs) provide a unique model for studying human early embryonic development. We have previously shown that Activin/Nodal signaling contributes to maintaining pluripotency of hESCs, which are derivatives of the inner cell mass. Here we further demonstrate that the inhibition of Activin/Nodal signaling results in the loss of hESC pluripotency and trophoblast differentiation, similar to BMP4-induced trophoblast differentiation from hESCs. We also show that the trophoblast induction effect of BMP4 correlates with and depends on the inhibition of Activin/Nodal signaling. However, the activation of BMP signaling is still required for trophoblast differentiation when Activin/Nodal signaling is inhibited. These data reveal that the early lineage segregation of hESCs is determined by the combinatorial signals of Activin/Nodal and BMP. 相似文献
48.
Phosphorylation of serine-15 of maize leaf sucrose synthase. Occurrence in vivo and possible regulatory significance. 总被引:7,自引:3,他引:7 下载免费PDF全文
S C Huber J L Huber P C Liao D A Gage R W McMichael Jr P S Chourey L C Hannah K Koch 《Plant physiology》1996,112(2):793-802
Experiments were conducted to determine whether sucrose synthase (SuSy) was phosphorylated in the elongation zone of maize (Zea mays L.) leaves. The approximately 90-kD subunit of SuSy was 32P-labeled on seryl residue(s) when excised shoots were fed [32P]orthophosphate. Both isoforms of SuSy (the SS1 and SS2 proteins) were phosphorylated in vivo, and tryptic peptide-mapping analysis suggested a single, similar phosphorylation site in both proteins. A combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and automated Edman sequencing analysis unequivocally identified the phosphorylation site in the maize SS2 protein as serine-15. This site was phosphorylated in vitro by endogenous protein kinase(s) in a strictly Ca(2+)-dependent manner. A synthetic peptide, based on the phosphorylation site sequence, was used to identify and partially purify an endogenous Ca(2+)-dependent protein kinase(s) from the maize leaf elongation zone and expanding spinach leaves. Phosphorylation of SuSy in vitro selectively activates the cleavage reaction by increasing the apparent affinity of the enzyme for sucrose and UDP, suggesting that phosphorylation may be of regulatory significance. Conservation of the phosphorylation site, and the sequences surrounding it, among plant species suggests that phosphorylation of SuSy may be widespread, if not universal, in plants. 相似文献
49.
Junna Wang Chong Li Xinbin Duan Daqing Chen Shunxin Feng Huihuang Luo Qidong Peng Wengen Liao 《Freshwater Biology》2014,59(7):1343-1360
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50.