芒果APl同源基因的克隆及其生物信息学分析

我们采用RT-PCR方法克隆了2个APl同源基因全长cDNA,分别命名为MAPl-1(GenBank accession No.FJ529206)和MAPl-2(GenBank accession No.FJ529207).MAPl-1编码247个氨基酸,开放阅读框长度为741 bp,蛋白质分子量为28.54kD,等电点为8.31;MAPl-2编码248个氨基酸,开放阅读框长度为744 bp,蛋白质分子量为28.78 kD,等电点为8.70.同源性分析表明,它们的核苷酸序列与其它木本植物APl同源基因的一致性为72%～81%.实验分析表明,MAPl-1和MAPl-2第1至第61个氨基酸含有一个MADS盒结构域,第88至第178个为K盒结构域;两个基因均定位于细胞核,且功能位点分布存在着不同,推测这两个基因在花器官发育过程中的功能存在差异.蛋白二级结构预测显示,MAPl-1蛋白有12个a-螺旋,4个β折叠区,14个β-转角;而MAPl-2蛋白有11个a-螺旋,5个β折叠区,15个β-转角:其大多数氨基酸具有亲水性.本研究有助于进一步了解芒果的开花分子机理及成花的生物学发育阶段.     

种子老化诱导小麦染色体畸变及大麦醇溶蛋白带型频率变化的研究

通过时20份小麦种质发芽率和根尖细胞染色体畸变的测定,结果表明同一品种贮藏于中期库的低发芽率种质,其染色体畸变率明显高于贮藏于长期库的高发芽率种质.从总体上看,种子根尖细胞染色体畸变率与发芽率呈负显著相关,而与贮藏年限无显著相关.但对长期库和中期库的种质分别进行统计分析,种子根尖染色体畸变率与发芽率和贮藏年限均无显著相关.对大麦地方品种"普乃干木"的醇溶蛋白分析表明,该品种有4种biotype,随着发芽率的下降,其群体中的4种bio-type的频率发生了变化,当发芽率从95%降到34%时,其中一种biotype出现了消失,而有一种biotype频率从83%上升至95%,此结果表明,种子生活力下降和不同biotype种子存活能力存在差异,可能导致了异质种质材料遗传选择和漂变的发生.     

水稻种子内生细菌多样性及其分泌植物生长素能力的测定

[目的]探讨水稻种子内生细菌的多样性并测定其分泌IAA能力.[方法]采用传统的可培养方法分离水稻种子内生细菌,并通过16S Rrna基因序列分析初步确定分离菌株的系统发育地位,利用比色法进一步对不同种类菌株产植物生长素(IAA)能力进行定性、定量检测.[结果]共分离纯化获得66株内生细菌菌株,分属于5个类群的15个属26个种.以26株细菌为代表对其进行分泌生长素(IAA)能力的定性及定量测定,共发现19株细菌可分泌生长素或其类似物,其中Z10、Z17、Z14和Z20 4株内生细菌具较强的分泌植物生长素能力.[讨论]分离得到的内生细菌表现了水稻种子内生细菌的多样性,其中某些细菌对植物有一定的促生功能.     

2011年、2013年和2016年医院内获得性血流感染常见病原菌分布及其耐药性分析

动态监测2011年、2013年和2016年我国不同地区医院内获得性血流感染病原菌分布及耐药进展趋势。从全国10个城市回顾性收集血流感染病原菌非重复性株,采用琼脂稀释法或微量肉汤稀释法进行药物敏感性试验,采用Whonet 5.6软件对药敏试验结果进行分析。收集的2 248株血流感染病原菌中革兰阴性杆菌为1 657株 (占73.7%),革兰阳性球菌为591株 (占26.3%)。分离率排名前五的病原菌依次为大肠埃希菌 (32.6%,733株/2 248株)、肺炎克雷伯菌 (14.5%,327株/2 248株)、金黄色葡萄球菌 (10.0%,225株/2 248株)、鲍曼不动杆菌 (8.7%,196株/ 2 248株) 和铜绿假单胞菌 (6.2%,140株/2 248株)。血流感染分离的革兰阴性杆菌对抗菌药物体外敏感率较高的抗菌药物依次为粘菌素 (96.5%,1 525株/1 581株,不包括天然耐药菌株)、替加环素 (95.6%,1 375株/1 438株,不包括天然耐药菌株)、头孢他啶/克拉维酸 (89.2%,1 112株/1 246株)、阿米卡星 (86.4%,1 382株/1 599株) 和美罗培南 (85.7%,1 376株/1 605株);革兰阳性球菌对抗菌药物体外敏感率较高的抗菌药物依次为替加环素、替考拉宁和达托霉素 (敏感率均为100.0%)、万古霉素和利奈唑胺 (敏感率均为99.7%)。2011年、2013年和2016年产超广谱β-内酰胺酶肠杆菌科细菌分离率分别为50.6% (206株/407株)、49.8% (136株/273株) 和38.9% (167株/429株);碳青霉烯不敏感肠杆菌科细菌分离率分别为2.2% (9株/408株)、4.0% (16株/402株) 和3.9% (17株/ 439株);多重耐药鲍曼不动杆菌分离率分别为76.4% (55株/72株)、82.7% (43株/52株) 和87.5% (63株/72株),多重耐药铜绿假单胞菌分离率分别为9.8% (5株/51株)、20.0% (7株/35株) 和13.0% (7株/54株);甲氧西林耐药金黄色葡萄球菌的分离率分别为51.9% (41株/79株)、29.7% (19株/64株) 和31.7% (26株/82株)。屎肠球菌和粪肠球菌中高水平庆大霉素耐药株分离率分别为43.2% (48株/111株) 和40.9% (27株/66株)。碳青霉烯不敏感肠杆菌科细菌中肺炎克雷伯菌居首位,占57.1% (24株/42株) 。肠杆菌科细菌中分离出30株替加环素不敏感株,其中肺炎克雷伯菌占76.7% (23株/30株);分离出粘菌素耐药肠杆菌科细菌39株,其中大肠埃希菌、阴沟肠杆菌和肺炎克雷伯菌分别占43.6% (17株/39株)、35.9% (14株/39株) 和15.4% (6株/39株)。医院获得性血流感染病原菌主要为革兰阴性杆菌 (以大肠埃希菌和肺炎克雷伯菌为主),其对替加环素、粘菌素和碳青霉烯类药物的敏感率较高;革兰阳性球菌中分离率最高的为金黄色葡萄球菌,其次为屎肠球菌,这两种细菌对替加环素、达托霉素、利奈唑胺、万古霉素和替考拉宁的敏感率较高。粘菌素耐药肠杆菌科细菌、替加环素不敏感肠杆菌科细菌、利奈唑胺或万古霉素不敏感革兰阳性球菌的分离,警示临床高度关注,仍需动态监测耐药进展趋势。     

Characterization of humoral responses in mice immunized with plasmid DNAs encoding SARS-CoV spike gene fragments

The immunological characteristics of SARS-CoV spike protein were investigated by administering mice with plasmids encoding various S gene fragments. We showed that the secreting forms of S1, S2 subunits and the N-terminus of S1 subunit (residues 18-495) were capable of eliciting SARS-CoV specific antibodies and the region immediate to N-terminus of matured S1 protein contained an important immunogenic determinant for elicitation of SARS-CoV specific antibodies. In addition, mice immunized with plasmids encoding S1 fragment developed a Th1-mediated antibody isotype switching. Another interesting finding was that mouse antibodies elicited separately by plasmids encoding S1 and S2 subunits cooperatively neutralized SARS-CoV but neither the S1 nor S2 specific antibodies did, suggesting the possible role of both S1 and S2 subunits in host cell docking and entry. These results provide insights into understanding the immunological characteristics of spike protein and the development of subunit vaccines against SARS-CoV.     

Challenge of weed risk assessment (WRA) for ecological restoration in China: The case of Rhus typhina L. and the new officially released weed risk assessment system

China has conducted many ecological restoration projects to alleviate environmental degradation, with numerous alien species having good adaptability widely used for fast effect. However, unsuitable plant selection may bring negative impacts and even cause biological invasion. Weed risk assessment (WRA) is therefore indispensable, yet it is often contentious especially concerning those species that has been widely utilized before weedy attributes were noted. In this paper, we take Rhus typhina L. as an example to illustrate how scientific researches and social factors can influence the evaluation of alien species and cause challenge to WRA. The evaluation of this species is not only a pure scientific issue but also influenced by many factors such as the introduction history, current utilization status in afforestation, and divergent underlying values varying through persons and sectors. These factors determined the kind of data to be assessed, which lead to different evaluations, therefore, causing challenge to its WRA. We further examined newly officially released WRA system in China from the invasion biology viewpoint, arguing that it had some major flaws in design and validation and need much improvement. Considering the human dimension and biological characters together, we suggest that the “black list” and “green list” approaches with rigorous expert assessment should be adopted simultaneously in alien species management in China.     

Expression and purification of the catalytic domain of human vascular endothelial growth factor receptor 2 for inhibitor screening

Vascular endothelial growth factor (VEGF), an endothelial cell-specific mitogen, can act in tumor-induced angiogenesis by binding to specific receptors on the surface of endothelial cells. One such receptor, VEGFR-2/KDR, plays a key role in VEGF-induced angiogenesis. Here, we expressed the catalytic domain of VEGFR-2 as a soluble active kinase using Bac-to-Bac expression system, and investigated correlations between VEGFR-2 activity and enzyme concentration, ATP concentration, substrate concentration and divalent cation type. We used these data to establish a convenient, effective and non-radioactive ELISA screening technique for the identification and evaluation of potential inhibitors for VEGFR-2 kinase. We screened 200 RTK target-based compounds and identified one (TKI-31) that potently inhibited VEGFR-2 kinase activity (IC50=0.596 microM). Treatment of NIH3T3/KDR cells with TKI-31 blocked VEGF-induced phosphorylation of KDR in a dose-dependent manner. Moreover, TKI-31 dose-dependently suppressed HUVEC tube formation. Thus, we herein report a novel, efficient method for identifying VEGFR-2 kinase inhibitors and introduce one, TKI-31, that may prove to be a useful new angiogenesis inhibitor.     

Cyanidin-3-glucoside, a natural product derived from blackberry, exhibits chemopreventive and chemotherapeutic activity

Epidemiological data suggest that consumption of fruits and vegetables has been associated with a lower incidence of cancer. Cyanidin-3-glucoside (C3G), a compound found in blackberry and other food products, was shown to possess chemopreventive and chemotherapeutic activity in the present study. In cultured JB6 cells, C3G was able to scavenge ultraviolet B-induced *OH and O2-* radicals. In vivo studies indicated that C3G treatment decreased the number of non-malignant and malignant skin tumors per mouse induced by 12-O-tetradecanolyphorbol-13-acetate (TPA) in 7,12-dimethylbenz[a]anthracene-initiated mouse skin. Pretreatment of JB6 cells with C3G inhibited UVB- and TPA-induced transactivation of NF-kappaB and AP-1 and expression of cyclooxygenase-2 and tumor necrosis factor-alpha. These inhibitory effects appear to be mediated through the inhibition of MAPK activity. C3G also blocked TPA-induced neoplastic transformation in JB6 cells. In addition, C3G inhibited proliferation of a human lung carcinoma cell line, A549. Animal studies showed that C3G reduced the size of A549 tumor xenograft growth and significantly inhibited metastasis in nude mice. Mechanistic studies indicated that C3G inhibited migration and invasion of A549 tumor cells. These finding demonstrate for the first time that a purified compound of anthocyanin inhibits tumor promoter-induced carcinogenesis and tumor metastasis in vivo.     

浙江西门岛海洋特别保护区大型底栖动物功能群特征及其与环境的关系

为研究浙江西门岛海洋特别保护区大型底栖动物功能群的变化规律及其与环境因子的关系,作者分别于2010年4月(春季)、11月(秋季),2011年8月(夏季)和2012年2月(冬季)进行了4个航次的大型底栖动物调查,共鉴定出大型底栖动物78种,根据其食性类型划分为浮游生物食者、植食者、肉食者、杂食者、碎屑食者5种功能群.各功能群平均密度从高到低依次为浮游生物食者＞肉食者＞植食者＞碎屑食者＞杂食者,平均生物量从高到低依次为浮游生物食者＞碎屑食者＞肉食者＞杂食者＞植食者.单因素方差分析结果表明,大型底栖动物各功能群的密度和生物量季节间均无显著性差异.典范对应分析结果表明,影响大型底栖动物功能群的主要环境因子包括温度、溶解氧、溶解态无机磷和表层沉积物的中值粒径,排序轴对功能群-环境关系的贡献率计算结果表明环境变量可以较好地解释功能群的变化情况.