深圳市宝安区蔬菜农药残留研究

根据2006年、2007年和2008年对55种蔬菜、共27551份样品农药残留的检测结果,分析了广东深圳市宝安地区蔬菜农药残留的状况和规律.结果表明:随着政府各项监督管理措施的落实,宝安地区蔬菜农药残留超标率逐年下降,2006年为4.35%,2007年为4.34%,2008年为1.41%;每年6～8月超标率最低,而冬春两季超标率较高;检出超标率最高的农药是有机磷类农药,包括甲基异柳磷、治螟磷、毒死蜱和敌敌畏,其次是氯氰菊酯和甲氰菊酯等拟除虫菊酯类农药;在抽检的55种蔬菜中超标率较高的是几种十字花科蔬菜,依次是芥菜、小白菜和菜心.     

Agrobacterium‐produced and exogenous cytokinin‐modulated Agrobacterium‐mediated plant transformation

Agrobacterium tumefaciens is a plant pathogenic bacterium that causes neoplastic growths, called ‘crown gall’, via the transfer and integration of transferred DNA (T‐DNA) from the bacterium into the plant genome. We characterized an acetosyringone (AS)‐induced tumour‐inducing (Ti) plasmid gene, tzs (trans‐zeatin synthesizing), that is responsible for the synthesis of the plant hormone cytokinin in nopaline‐type A. tumefaciens strains. The loss of Tzs protein expression and trans‐zeatin secretions by the tzs frameshift (tzs‐fs) mutant is associated with reduced tumorigenesis efficiency on white radish stems and reduced transformation efficiencies on Arabidopsis roots. Complementation of the tzs‐fs mutant with a wild‐type tzs gene restored wild‐type levels of trans‐zeatin secretions and transformation efficiencies. Exogenous application of cytokinin during infection increased the transient transformation efficiency of Arabidopsis roots infected by strains lacking Tzs, which suggests that the lower transformation efficiency resulted from the lack of Agrobacterium‐produced cytokinin. Interestingly, although the tzs‐fs mutant displayed reduced tumorigenesis efficiency on several tested plants, the loss of Tzs enhanced tumorigenesis efficiencies on green pepper and cowpea. These data strongly suggest that Tzs, by synthesizing trans‐zeatin at early stage(s) of the infection process, modulates plant transformation efficiency by A. tumefaciens.     

Seasonal variation in foliar carbon exchange in Pinus radiata and Populus deltoides: respiration acclimates fully to changes in temperature but photosynthesis does not

We investigated seasonal variation in dark respiration and photosynthesis by measuring gas exchange characteristics on Pinus radiata and Populus deltoides under field conditions each month for 1 year. The field site in the South Island of New Zealand is characterized by large day-to-day and seasonal changes in air temperature. The rate of foliar respiration at a base temperature of 10 °C ( R ₁₀) in both pine and poplar was found to be greater during autumn and winter and displayed a strong downward adjustment in warmer months. The sensitivity of instantaneous leaf respiration to a 10 °C increase in temperature ( Q ₁₀) was also greater during the winter period. The net effect of this strong acclimation was that the long-term temperature response of respiration was essentially flat over a wide range of ambient temperatures. Seasonal changes in photosynthesis were sensitive to temperature but largely independent of leaf nitrogen concentration or stomatal conductance. Over the range of day time growth temperatures (5–32 °C), we did not observe strong evidence of photosynthetic acclimation to temperature, and the long-term responses of photosynthetic parameters to ambient temperature were similar to previously published instantaneous responses. The ratio of foliar respiration to photosynthetic capacity ( R _d/ A _sat) was significantly greater in winter than in spring/summer. This indicates that there is little likelihood that respiration would be stimulated significantly in either of these species with moderate increases in temperature – in fact net carbon uptake was favoured at moderately higher temperatures. Model calculations demonstrate that failing to account for strong thermal acclimation of leaf respiration influences determinations of leaf carbon exchange significantly, especially for the evergreen conifer.     

匙叶八角中一个新的倍半木脂素

从匙叶八角(Illicium spathulatum)果实中分离得到一个新的倍半新木脂素,通过现代波谱技术确定其结构为7′, 8′-反式-7″, 8″ 顺式-5, 3′,3″-三甲氧基倍半新木脂素。     

重组干扰素上调草鱼干扰素系统基因的表达

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竹亚科刚竹属植物新资料

描述了竹亚科Bambusoideae刚竹属Phyllostachys Sieb. et Zucc.的2个新种和5个新变型：瓜竹Ph. longiciliata、浙江甜竹Ph. zhejiangensis、黄槽黄古竹Ph. angusta f. flavosulcata、绿槽人面竹Ph. aurea f. koi、蝶毛竹 Ph. edulis f. abbreviata、黄条燥壳竹Ph. hirtivagina f. flavovittata和花竹Ph. nidularia f. basipilis;作出3个新组合变型：厚皮毛竹Ph. edulis f. pachyloen、安吉锦毛竹Ph. edulis f. anjiensis和花秆早竹Ph. violascens f. viridisulcata;对金条竹Ph. aureosulcata f. flavostriata、对花竹Ph. bambusoides f. duihuazhu、黄槽斑竹Ph. bambusoides f. mixta和黄皮毛竹Ph. edulis f. holochrysa的模式标本给予了重新指定。     

肿瘤干细胞表面标志物及主要信号通路

肿瘤干细胞是存在于肿瘤组织中的具有自我更新、增殖、分化的部分细胞群,对肿瘤的发生、发展有十分重要的作用. 肿瘤干细胞特异的表面分子及其异常活化的信号通路,是其区别于其他肿瘤细胞的特性.寻找和鉴定特异的肿瘤干细胞的表面标志物,从而识别肿瘤组织中的肿瘤干细胞,并进行相关信号调控机制研究,是肿瘤早期诊断及肿瘤干细胞靶向治疗的关键. 本文简要概述了肿瘤干细胞相关的表面标志物及信号通路的研究进展,旨在为进一步开展针对肿瘤干细胞的抗体靶向治疗提供新思路.     

小鼠脑组织及培养神经元Neuro-2a 在内质网应激反应时的基因表达谱分析

内质网是真核细胞的重要细胞器。某些细胞内外因素如病原体感染等能引起从内质网到胞浆和胞核的信号传导途径活化,即内质网应激反应。但是,目前国内外尚无针对内质网应激反应的基因表达谱分析报道。本研究中,用3种已报道的内质网应激反应诱导剂,包括蛋白质糖基化抑制剂衣霉素(tunicamycin)、内质网Ca ²⁺-ATPases抑制剂毒胡萝卜素（thapsigargin）和乙脑病毒(Japanese encephalitis virus, JEV),分别处理小鼠颅腔和小鼠脑神经瘤细胞（Neuro-2a）,试剂处理组与未处理组的第二代RNA测序分析发现,衣霉素、毒胡萝卜素和乙脑病毒在体外和体内均引起分子伴侣基因Hsp70表达上调,诱导内质网应激反应。衣霉素、毒胡萝卜素和乙脑病毒体外处理诱导的内质网应激反应信号通路中,基因差异表达相似性高于体内处理组。乙脑病毒和糖基化抑制剂衣霉素体内外处理,主要诱导内质网应激反应的非折叠蛋白质反应信号通路,引起相关基因Atf4、Bip、Edem和Perk等表达上调。内质网Ca ²⁺-ATPases抑制剂毒胡萝卜素主要诱导内质网超负荷反应,激活NF-κB信号通路。乙脑病毒诱导的内质网应激反应相关差异表达基因数量最多,体外与体内合计有40种。乙脑病毒体内外处理上调的基因包括Bax、Casp12、Atf4、Bip、Edem和Perk等,下调的基因包括Sec23/24、Nef、Svip和Jnk等。糖基化抑制剂衣霉素体内外处理上调基因包括Gadd34、Atf4、Ermani和Bip等,下调基因包括Grp94、Atf6、Sec23/24和Nef等。内质网Ca ^-2+-ATPases抑制剂毒胡萝卜素体内外处理上调的基因包括Sec61、Trap和Ask1等。衣霉素、毒胡萝卜素和乙脑病毒体内外处理也通过内质网应激反应,调控与炎症或凋亡相关的MAPK信号通路和P53信号通路。本研究首次通过使用3种内质网应激反应诱导剂分别处理小鼠和细胞,揭示了体内外内质网应激反应引起的基因表达谱变化,为内质网应激反应相关疾病的治疗提供了新思路。     

Rho激酶抑制剂Y-27632促进大鼠成骨细胞早期分化

已知Rho激酶抑制剂可调控细胞骨架重建,激活相关转录因子,进而促进细胞分化。然而,关于Rho激酶抑制剂对细胞骨架和成骨细胞分化的影响及两者之间关系尚未见报道。本研究旨在阐明Rho激酶抑制剂Y 27632调控细胞骨架重建,促进成骨分化。取新生SD大鼠头盖骨组织体外培养细胞传至第3代,给予Rho激酶抑制剂Y-27632进行干预。采用罗丹明标记的鬼笔环肽对细胞骨架进行细胞化学染色。结果显示,培养1 d和2 d,Rho激酶抑制剂Y-27632处理的细胞呈现多角形,并伴有部分伪足形成。细胞培养4 d和7 d,Y-27632处理的细胞碱性磷酸酶（alkaline phosphatase, ALP）活性明显增加（P<0.01）。实时定量PCR揭示,加Y-27632处理细胞的骨分化相关基因Runx2、Alp、β-catenin(β-cat)、osteopontin(Opn)的mRNA表达水平均显著高于对照细胞（P<0.05或P<0.01）。以上结果证明,Rho激酶抑制剂Y 27632能够影响大鼠成骨细胞的形态,并有促进其分化作用。本研究为骨代谢疾病及组织工程的研究提供了新的线索和启示。     

黄茅海河口虎跳门和崖门浮游动物群落的比较

于2006年11月～2007年8月对珠江口西部的黄茅海河口区浮游动物进行了四个航次的生态调查,分别在入海口处虎跳门和崖门各设置1个采样断面,分析了两口门的水文特征和水体理化因子特点及其两者之间的差异显著性,调查研究了浮游动物的种类组成、密度、生物量和多样性指数等分布特征。共检出浮游动物50种,桡足类占优势,24种,其次为轮虫类,为12种,枝角类和原生动物分别各为5种,多毛类、异足类、糠虾类和螺类各1种,此外,还有桡足类幼虫以及未知种类2种。分析得出,在调查周期内,虎跳门和崖门浮游动物的密度、生物量及多样性指数值的差异不显著,这可能与两口门的水体理化因子及浮游植物群落构成没有显著性差异有着直接的原因,而受两口门水动力条件不同的影响较小。由聚类分析结果可知,四个季节可分为两大组,虎跳门和崖门秋、冬两季浮游动物群落结构较为相近,春、夏两季浮游动物群落结构较为相近。