黄瓜育成品种"春玉"RAPD指纹图谱分析

从300条随机引物中筛选出能稳定扩增的26个引物．对黄瓜育成品种“春玉”等21个实验材料进行扩增,在扩增出的173条谱带中,多态性带有80条,比例为46．24％。“春玉”在用引物E13扩增时有特异缺失条带,大小为400bp,可作为特征性指纹图谱,为其产权保护提供分子依据。利用各材料的DNA指纹可将不同参试材料鉴别出来。同时利用MEGA软件进行UPGMA聚类分析,将参试材料在相似系数0．706处分为4个组群。     

放线菌药物资源开发面临的问题与对策

放线菌药物的开发已取得了极其辉煌的成就, 对医疗事业的发展和人类健康做出了重大贡献。然而, 随着放线菌药物资源的长期开发和利用, 也面临诸多问题。如: 包袱沉重, 去重复难度极大, 因而投资周期长、耗资巨, 风险大; 药物开发赶不上病原菌抗药性的增加及不断出现的新疾病; 虽然未知放线菌甚多, 但发现难度大。为此, 提出了从化学、菌种和基因三方面开展放线菌药物研究的应对策略, 以解决限制放线菌药物资源持续利用和发展的瓶颈。     

检测伪狂犬病的PCR方法的建立及其在临床诊断中的应用

根据文献,通过计算机分析设计并合成了1对用于扩增伪狂犬病病毒(pseudorabies virus,PRV)gB基因281bp片段的引物,上游引物(P1)位于gB基因的1827～1851位,下游引物(P2)位于gB基因的2083～2107位.以PRV闽A株细胞培养毒为模板,筛选最佳反应条件和试剂工作浓度,建立了检测PRV的PCR方法.应用该方法对保存的16株伪狂犬病强弱毒株的细胞培养液进行基因扩增,均获得了281bp的特异性目的DNA片段.可是,对正常细胞与其它6种引起猪病毒性疫病相关病毒进行检测,结果均为阴性,没有出现交叉反应.对扩增产物测序,结果序列与文献报道一致,证明PCR扩增产物和方法的特异性.对PRV闽A株细胞毒提取物DNA进行检测,其最低检出量为15.8pg.用病毒分离、双抗体夹心ELISA和PCR等3种方法检测1994～2000年期间送检的临床样品和保存的PRV毒种,对所获得的结果进行χ2分析,证明PCR检出率明显高于前2种方法.对1999～2001年期间广东、福建、海南等省的76个大中型猪场送检的348份病料进行检测,检出阳性病料68份,病料阳性率为19.54%;检出阳性猪场27个,猪场阳性率为35.53%.对27个阳性猪场分析发现,种猪场阳性率为7.41%(2/27),商品猪场阳性率为92.59%(25/27).PRV在自然发病猪体内分布较广,脑、肾、肺、脾、肝、淋巴结均有PRV的存在,PRV检出率最高的组织为脑,其检出率为5/5,依次为肾12/15、肺9/16、脾10/20、肝7/18、淋巴结4/11等.实验结果表明,所建立的PCR技术可用于伪狂犬病的快速诊断和流行病学调查.     

细菌质粒的消除

利用化学消除剂或改变生长条件可以消除细菌中的质粒,除宿主菌的特性及其所含质粒分子量大小之外,消除率还与消除剂浓度,作用时间有关,嵌合染料适用于消除大肠杆菌中的质粒,十二烷基硫酸钠对具有性纤毛的细菌作用效果较好,适当提高培养温度可消除一些细菌中的质粒,胸腺嘧啶限量法仅适用于其营养缺陷菌株的质粒消除,利用原生质体的形成与再生及反复冻融菌体均可消除细菌中的质粒。     

ROLE OF RICE VOLATILES IN THE FORAGING BEHAVIOUR OF CYRTORHINUS LIVIDIPENNIS REUTER

Abstract Experiments were conducted in laboratory to study the impacts of rice genotypes and nitrogen levels on the preference of the egg predator, Cyrtorhinus lividipennis , for eggs of brown planthopper(BPH), Nilaparvata lugens (Stal), and their relation to the rice volatiles. In two-choice tests, the female predators showed different preference for BPH eggs on different rice genotypes, but not for BPH eggs on rice plants treated with different levels of nitrogen. The olfactory response test revealed that more predator oriented to the odour from healthy rice plants compared with the plain air (control); the predator preferred BPH nymph-damaged plants to healthy plants, and BPH female adult-damaged plants to BPH nymph-damaged plants. The comparative studies between rice genotypes and nitrogen levels indicated that there were obvious differences in attractiveness to the predator between rice genotypes, while there was no significant difference between rice plants treated with different levels of nitrogen. The results showed that rice volatiles played an important role in mediating the foraging behaviour of C. lividipennis . Implications for augmenting the effectiveness of natural enemies by adjusting rice attributes and cultural practices are discussed.     

CH4 emission with differences in atmospheric CO2 enrichment and rice cultivars in a Japanese paddy soil

A pot experiment was conducted to investigate CH₄ emissions from a sandy paddy soil as influenced by rice cultivars and atmospheric CO₂ elevation. The experiment with two CO₂ levels, 370 μL L⁻¹ (ambient) and 570 μL L⁻¹ (elevated), was performed in a climatron, located at the National Institute for Agro‐Environmental Sciences, Tsukuba, Japan. Four rice cultivars were tested in this experiment, including IR65598, IR72, Dular and Koshihikari. Tiller number, root length and grain yield were clearly larger under elevated CO₂ than under ambient CO₂. IR72 and Dular showed significantly higher tiller number, root length and grain yield than Koshihikari and IR65598. Average daily CH₄ fluxes under elevated CO₂ were significantly larger by 10.9–23.8% than those under ambient CO₂, and varied with the cultivars in the sequence Dular ≧ IR72>IR65598 ≧ Koshihikari. Dissolved organic C (DOC) content in the soil was obviously higher under elevated CO₂ than under ambient CO₂ and differed among the cultivars, in the sequence IR72>Dular>Koshihikari>IR65598. The differences in average daily CH₄ fluxes between CO₂ levels and among the cultivars were related to different root exudation as DOC content, root length and tiller number. This study indicated that Koshihikari should be a potential cultivar for mitigating CH₄ emission and simultaneously keeping stable grain yield, because this cultivar emitted lowest CH₄ emission and produced medium grain yield.     

热水处理对金柑果实采后腐烂及生理特性的影响

金柑是果皮和果肉同食的柑果类型,对采后处理要求极为严格。该研究以金柑(Fortunella crassifolia)为材料,研究了其经30、40和50℃热水浸泡后果实的腐烂率、失重率、可溶性固形物、硬度、有机酸、细胞渗透率以及抗氧化酶活性变化。结果表明:经30℃热水处理5 min的果实失重率高于对照,而经40℃和50℃处理的果实失重率低于对照或差异不显著。经热水处理的果实总酸含量略低于对照,可溶性固形物含量在18%上下波动且差异不显著。热水处理可提高果实硬度,降低贮藏前期果实细胞渗透率以及贮藏过程中果实过氧化物酶和超氧化物歧化酶活性,激发过氧化氢含量升高,可有效降低贮藏过程中金柑果实腐烂率,但不同采收期的金柑所需的热水处理温度和时间不同。对于1月初采收的果实,处理时间为5 min或10 min可降低果实腐烂率;2月初采收的果实,40℃或50℃热水处理10 min可有效降低果实腐烂率;3月初采收的果实,当处理温度达到50℃,处理时间达到10 min,才可有效降低果实腐烂率,且对果实品质没有明显的不利影响。     

Bumble bee species exhibit divergent responses to urbanisation in a Southern California landscape

1. Bees are ecologically important pollinators that are threatened by disease, habitat degradation, and habitat loss. Bee species that share ecological traits (e.g. body size, diet breadth, and sociality) may often respond similarly to environmental disturbance; however, few studies have examined the extent to which closely related, ecologically similar species exhibit divergent responses to the same forms of disturbance. 2. In the present study, the responses of bumble bees (Apidae: genus Bombus) to urbanization are examined by combining field surveys with the quantification of local‐ and landscape‐level variables using Geographic Information Systems (GIS). During the spring and summer of 2012 and 2013, 57, bumble bees were surveyed in 1‐ha plots in San Diego County, California that spanned a gradient of urbanisation. Species‐level, occurrence (presence/absence) data and logistic regressions were then used to identify determinants of Bombus occurrence across this landscape. 3. Approximately 1000 Bombus individuals belonging to three species were observed: B. californicus Smith, B. melanopygus Cresson, and B. vosnesenskii Radoszkowski. The occurrence of all Bombus species was negatively related to impermeable surface cover within study plots, but species responded uniquely to other plot‐scale variables and exhibited distinctive patterns of scale‐dependency with respect to impermeable surface cover surrounding plots. 4. Urbanisation negatively affected all three focal bumble bee species in this study. Species‐specific responses to plot‐scale and landscape‐scale variables presumably reflect interspecific trait differences (e.g. body size, tongue length, and foraging behaviour). Unique responses to urbanisation caution against pooling species into functional groups based merely on taxonomic relationships or perceived ecological similarities.     

脂氧合酶与猕猴桃果实后熟软化的关系

２０ ℃下贮藏果实的脂氧合酶（ＬＯＸ） 活性随着后熟进程持续上升,其活性与果实硬度的变化呈极显著负相关,油酸、亚油酸和亚麻酸等不饱和脂肪酸的组分比例变化较大,而棕榈酸和硬脂酸等饱和脂肪酸的组分比例变化很小;０ ℃贮藏果实中的ＬＯＸ 活性被强烈抑制,果实后熟软化进程被明显延缓,５ 种脂肪酸组分比例变化均较平稳;外源乙烯处理显著促进了ＬＯＸ 活性的增加,加速了果实后熟软化进程。     

乙酰胆碱酯酶在蚕豆保卫细胞中集中分布

动物细胞中,乙酰胆碱酯酶负责把乙酰胆碱水解为胆碱和乙酸以起到终止信号的作用。蚕豆（ＶｉｃｉａｆａｂａＬ．）保卫细胞原生质体表面具有特异的水解乙酰胆碱的酯酶,光可以激活该酶的活性。组织学定位的结果显示,酶反应产物主要分布于气孔保卫细胞内壁和腹壁的外侧及内壁和腹壁中,表明一种类似于动物突触传递的机制可能存在于气孔保卫细胞和周围细胞之间,即乙酰胆碱发挥作用后由乙酰胆碱酯酶分解以终止其作用;此外开放的气孔周围具有更高的酶活性,说明乙酰胆碱酯酶可通过水解气孔周围的乙酰胆碱而调控气孔运动