国外花生种质资源引种鉴定

从法国国际农艺发展研究中心(CIRAD)引入33份花生种质资源,对它们的主要农艺性状、品质、抗性等进行了较为全面的观察鉴定,筛选出高产种质(单株生产力大于60g)17份,蛋白质含量高种质(大于30%)5份,粗脂肪含量高种质(大于50%)15份。     

微生态制剂对慢性肝衰竭患者肠道菌群的影响

目的探讨微生态调节剂双歧杆菌三联活菌对慢性肝衰竭患者肠道菌群的影响。方法根据治疗方法不同将46例慢性肝衰竭患者随机分为治疗组和对照组各23例,两组均给予慢性肝衰竭常规治疗,治疗组在上述基础上给予双歧杆菌三联活菌胶囊,210mg／粒,每次2粒,2次／d,疗程2周。观察治疗前后两组患者的肠道菌群菌落计数变化及血清总胆红素（TBiL）、凝血酶原时间（PT）变化。结果两组患者在实验前肠道菌群、TBiL、PT比较差异均无统计学意义（P〉0．05）。治疗2周后,对照组患者治疗前后肠道菌群无明显变化（P〉0．05）,TBiL、PT有所下降但不显著,治疗组患者的肠球菌、双歧杆菌、乳杆菌以及酵母样真菌的菌落数均较治疗前明显增加,TBiL、PT较前明显好转（P〈0．05）。结论口服双歧杆菌三联活菌制剂可以促进慢性肝衰竭患者肠道正常菌群的恢复及改善肝功能。     

辐照外源DNA导入番茄的研究

利用＾６０Ｃｏ的γ射线辐照外源ＤＮＡ导入选育番茄。研究表明,辐照外源ＤＮＡ导入后,提高Ｄ０代的座果率;使Ｄ０代结籽数减少,但比没有辐照的ＤＮＡ导入要多,这些与剂量有一定的关系,差别明显。果脐有变化,这与短截花柱有关。在Ｄ１代的幼苗观察中,发现供体的叶形和幼苗茎杆颜色（紫色）的显性基因,已在受本中得到表达。     

The importance of fire refugia in the recolonization of a fire-sensitive conifer in northern Patagonia

Seed dispersal and seedling establishment are essential for plant recolonization after disturbances, especially for plants that rely exclusively on sexual reproduction such as post-fire colonizer trees. Fire refugia may play a key role not only allowing trees to survive fire, but also functioning as seed sources after it. The estimation of seed dispersal and seedling establishment are essential for assessing plant recolonization ability, understanding landscape dynamics and determining which areas may not be able to recover due to lack of seed arrival. Here we study the post-fire recolonization ability of Austrocedrus chilensis (Cordilleran Cypress) from fire refugia in burned areas of northwest Patagonia, Argentina. We mapped all female trees, saplings and seedlings within and around fire refugia, recorded the reproductive capacity of female trees and characterized the microsite conditions for establishment. We used an inverse modelling approach and Approximate Bayesian Computation to estimate the seed dispersal kernel and the probability of seedling establishment. We found that the average dispersal distance of an A. chilensis seed was 88.52 m. The dispersal kernel was fat-tailed, meaning that A. chilensis has the capacity of producing accelerating expansions. Large woody debris, litter, and the protection of shrubs were the most important factors associated with the presence of recruits. We highlight the importance of fire refugia as seed sources for the recolonization of burned areas and thus the relevance of protecting these places to allow the persistence of fire-sensitive species.     

环境因素和个体差异对雌虫产卵量的影响

昆虫的产卵是昆虫生物学最重要的内容之一,雌虫产卵量的多少受多种环境因素和雌虫个体因素的影响。本文从环境因素和个体因素两方面综述了影响雌虫产卵量的因素,包括温度、湿度、光照、温室气体、食物、密度、音乐、个体体型、交配、滞育等,分析了各因素影响产卵量的原因及其规律,并提出了未来的研究发展方向。不仅丰富了昆虫繁殖生物学的内容,也为田间害虫和室内养殖昆虫管理过程中的数量预测以及种群调控提供了科学依据。     

A redox-dependent interaction between two electron-transfer partners involved in photosynthesis

Ferredoxin:NADP⁺:reductase (FNR) catalyzes one terminal step of the conversion of light energy into chemical energy during photosynthesis. FNR uses two high energy electrons photoproduced by photosystem I (PSI) and conveyed, one by one, by a ferredoxin (Fd), to reduce NADP⁺ to NADPH. The reducing power of NADPH is finally involved in carbon assimilation. The interaction between oxidized FNR and Fd was studied by crystallography at 2.4 Å resolution leading to a three-dimensional picture of an Fd–FNR biologically relevant complex. This complex suggests that FNR and Fd specifically interact prior to each electron transfer and disassemble upon a redox-linked conformational change of the Fd.     

Lack of prion transmission by sexual or parental routes in experimentally infected hamsters

Prion diseases are a group of neurodegenerative disorders affecting humans as well as captive and wild animals. The mechanisms and routes governing the natural spread of prions are not completely understood and several hypotheses have been proposed. In this study, we analyzed the effect of gender in prion incubation period, as well as the possibility of prion transmission by sexual and parental contact using 263K infected hamsters as a model. Our results show that males have significantly longer incubation periods compared with females when exposed to the same quantity of infectious material. Importantly, no evidence of sexual or parental prion transmission was found, even 500 d after sexual contact or birth, respectively. Western blotting and PMCA were unable to detect sub-clinical levels of PrP^Sc in experimental subjects, suggesting a complete absence of prion transmission by these routes. Our results show that sexual and parental transmission of prions does not occur in this model. It remains to be studied whether this conclusion is valid also for other prion strains and species.     

灵昆岛东滩潮间带大型底栖动物功能群及营养等级构成

2003年11月至2004年8月,在温州湾的灵昆岛东滩针对大型底栖动物群落进行了取样调查,利用调查数据进行功能群和营养等级构成研究。共得到大型底栖动物33种,隶属7门8纲21科,主要为软体动物、节肢动物甲壳类和环节动物多毛类。其中,高潮带25种,中潮带30种,低潮带14种。Margalef物种丰富度指数和Shannon—Weiner多样性指数均表现为：高潮带〉中潮带〉低潮带;Pielou均匀度指数和Simpson优势度指数表现为：高潮带〈中潮带〈低潮带。定性取样得到的浮游生物食者4种,植食者12种,肉食者8种,杂食者7种,碎屑食者2种,定量取样得到的分别为：3,8,5,3种和2种。定量取样获得数据中各个功能群种类数和密度季节间差异均不显著,不考虑季节变化因素肉食者和植食者密度在潮带间存在差异,杂食者和植食者种类数在潮带间存在差异,其他功能群密度和种类数数据在潮带间的差异不显著。研究显示了功能群的生境梯度变化,高潮带主导的功能群为肉食者,植食者和浮游生物食者;中潮带主导的功能群为肉食者和浮游生物食者;低潮带主导的功能群为肉食者,这些变化反映了不同潮带营养等级构成和食物来源的差异,由于生境中能提供的植物沿着高潮带,中潮带和低潮带方向递减,至低潮带未发现植食者;且由于中潮带的生境最为复杂,其功能群的构成也最为复杂;3个潮带的碎屑食者数量比较稳定。大型底栖动物群落与其食物来源一起共有4个营养等级,其中大型底栖动物占据了第2、3、4级,第1级主要碎屑、浮游生物和植物,第2级包括了碎屑食者、浮游生物食者和植食者,第3级主要是杂食者,第4级是肉食者,各个营养级、食物来源之间构成一张复杂的食物网。     

根据核DNA的ITS序列的RFLP分析鉴定稻属CD染色体组物种

稻属物种的染色体组类型有10种,其中具CD染色体组的物种有3种(Oryza alta Swallen,O.grandiglumis(Doell)Prod.和O.latifolia Desv.),仅分布在美洲中部和南部.这3个种在形态上和稻属其他染色体组的种比较容易区别,但它们彼此之间鉴别比较困难.近年来的研究表明,O.alta和O.grandiglumis应归并为1个种(O.grandiglumis),而O.latifolia应保持不变.本文基于代表不同分布区11个样品的核糖体转录间隔区(ITS)的77个克隆序列数据,利用DNA Striderl.2软件进行了限制性酶切位点分析,提出了一个鉴别CD染色体组物种的方法.方法的具体步骤是:(1)用通用引物扩增ITS片段;(2)用特异性的限制性内切酶Fok Ⅰ和/或Dra Ⅲ消化PCR扩增产物;(3)用1%的琼脂糖电泳并根据消化产物的多态性特征来鉴别不同物种.基于本文提出的核糖体ITS限制性片段多态性(RLFP)分析,可以快速和可靠地将稻属CD染色体组物种区别开来.