Artificial selection on allometry: change in elevation but not slope

To what extent within-species (static) allometries constitute a constraint on evolution is the subject of a long-standing debate in evolutionary biology. A prerequisite for the constraint hypothesis is that static allometries are hard to change. Several studies have attempted to test this hypothesis with artificial-selection experiments, but their results remain inconclusive due to various methodological issues. Here, we present results from an experiment in which we selected independently on the slope and the elevation of the allometric relationship between caudal-fin size and body size in male guppies (Poecilia reticulata). After three episodes of selection, the allometric elevation (i.e. intercept at constant slope) had diverged markedly between the lines selected to increase or decrease it, and showed a realized heritability of 50%. In contrast, the allometric slope remained unaffected by selection. These results suggest that the allometric elevation is more evolvable than the allometric slope, this latter representing a potential constraint on adaptive trait evolution. To our knowledge, this study is the first artificial-selection experiment that directly tests the evolvability of static allometric slopes.     

Piping Plover Chick Foraging,Growth, and Survival in the Great Plains

Abstract: We tested the hypothesis that piping plover (Charadrius melodus) habitat quality and chick survival on the Missouri River, USA, were lower on a cold-water reservoir and downstream from a hypolimnetic (cold-water) release dam with diel water fluctuations (Garrison Dam) than downstream from an epilimnetic dam (Gavins Point Dam). Plovers in adjacent alkali wetlands provided an index to the maximum reproductive potential in the region. Chicks gained weight more rapidly in the alkali wetlands than on epilimnetic and hypolimnetic river reaches. Invertebrate numbers and biomass were higher in the wetlands and epilimnetic reach, but chick survival was lower on the epilimnetic reach. Thus, piping plovers adapted to a variety of prey densities, and other factors, likely predation, reduced survival rates in the epilimnetic reach. Temporal and spatial variability in site quality indices suggests the need for a regional management strategy with different strategies at each site. Managers can minimize effects of local fluctuations in resource abundance and predators by ensuring protection of or creating geographically dispersed habitat. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):682–687; 2008)     

油菜叶片蛋白质组对机械损伤应答的初步分析

 植物在对抗昆虫的长期进化过程中形成了自我防御机制,能够产生特异的抗性蛋白来应对昆虫的取食。该文用机械损伤模拟害虫取食,研究和 对比了油菜(Brassica napus cv. Westar)在机械损伤前后可溶性总蛋白的含量变化并试图通过蛋白质组学技术来检测可能发生变化的蛋白质。 蛋白质定量检测发现,同一植株同一叶片损伤前后可溶性总蛋白含量差异显著,损伤后蛋白表达量增高。 蛋白质双向凝胶电泳及其差异显示分 析损伤前后的蛋白质组,表明有8个蛋白质点发生明显的上调或下调。选择其中2个差异蛋白点经过MALDI-TOF质谱鉴定,它们分别是Rubisco小 亚基前体、果糖-1,6-二磷酸醛缩酶和粪卟啉-3-氧化酶,这些蛋白质可能在油菜叶片应答机械损伤过程中对维持植物的生理功能起到重要作用 。     

乳酸菌黏附小鼠派伊尔结及影响因子的研究

目的研究乳酸菌结合小鼠派伊尔结（PP）的性质,确定乳酸菌黏附小鼠PP的影响因子。方法测定10株荧光标记的乳酸菌对PP组织切片黏附性,分析细菌表面疏水性和酵母、红细胞凝集性与黏附性的关系。结果凝集酵母、红细胞能力强的乳酸菌,PP黏附性强。除嗜酸乳杆菌（L.acidophilm）外,其他9株乳酸菌的表面疏水性与凝集酵母、红细胞的能力呈显著的负相关性（r=-0．60和r=-0．53,P〈0．05）。L.acidophilm黏附PP的能力最强。L．acidophilm黏附PP能力和红细胞凝集性均可被D（＋）-甘露糖、D（＋）-半乳糖抑制。结论乳酸菌黏附PP的能力受疏水性和表面特异性凝集素的影响。L.acidophilm表面D（＋）-甘露糖、D（＋）-半乳糖特异性凝集素可能参与黏附PP的过程。     

双价抗病基因导入籽瓜的遗传转化研究

以籽瓜主栽品种新籽瓜2号、五原籽瓜等为研究材料,用苗龄1-3d的子叶切块作外植体,不定芽诱导培养基为MS 6-BA2mg/L IBA 0.1mg/L,芽伸长培养基为MS KT0．2mg／L,诱导生根的培养基是MS IAA0．5mg／L。籽瓜遗传转化研究结果表明农杆菌感染时间以10min,共培养时间以2d为合适。共获得抗卡那霉素100mg／L的试管苗41个,PCR检测呈阳性的有15株,转化率为34．9％。该研究初步建立了籽瓜的遗传转化体系和转化体的检测体系。     

外源质粒pcDNA3s疫苗在小鼠体内组织代谢动力学研究

为分析外源质粒pcDNA3s肌肉注射后在小鼠体内的组织分布及评价整合到宿主基因组上的可能性．通过PCR方法检测质粒pcDNA3s经肌肉注射在各组织中的分布及随时间变化的情况．检测外源质粒在基因组DNA上的整合情况．注射后3h所有的组织均能检测到质粒,至第3周时只有胸腺和生殖器官能检测到质粒的存在,至第6周后各组织均为阴性、各组织基因组DNA经PCR扩增均为阴性．肌注外源质粒后,外源质粒在小鼠细胞内逐渐被清除,外源质粒不会整合到宿主染色体上．     

森林城市景观格局与热环境的关系——以龙泉市为例

景观格局分异特征在相当程度上影响着城市热环境.本研究以国家森林城市龙泉市为对象,通过地温反演和空间分析反映9类景观温度特征,运用景观格局分析方法从1～3.5 km 6个尺度探索格局指数与热环境的相关性.结果表明: 龙泉市高温区及次高温区主要分布于东北至西南一带,以城乡居民地为主,低温区和次低温区主要分布于西北、东南区域,以公益林为主;对海拔700 m以下区域各景观类型地表温度的统计发现,针叶林地、阔叶林地、针阔混交林地、竹林地、水域的地温均值相对较低,灌木林地、其他林地、耕地、建设用地的地温均值相对较高;对景观格局与热环境的分析发现,类型水平格局指数较景观水平格局指数更具实际意义,建设用地与热环境的相关系数可达0.835,针叶林地、阔叶林地、针阔混交林地、水域次之,在-0.5～-0.4,不同林地类型的降温效果在空间尺度上的表达不同,阔叶林地、针阔混交林地更利于在大尺度上降温;林地的面积和蓄积量越大,越易出现地表温度低值.     

Putative role of γ -aminobutyric acid (GABA) as a long-distance signal in up-regulation of nitrate uptake in Brassica napus L.

The relationship between nitrate influx, BnNrt2 nitrate transporter gene expression and amino acid composition of phloem exudate was investigated during N‐deprivation (short‐term experiment) and over a growth cycle (long‐term experiment) in Brassica napus L. The data showed a positive correlation between γ‐aminobutyric acid (GABA) in phloem exudate and nitrate uptake in the short‐ and the long‐term experiments. The hypothesis that this non‐protein amino acid could up‐regulate nitrate uptake via a long‐distance signalling pathway was tested by providing an exogenous GABA supply to the roots. The effect of GABA was compared with the effects of Gln, Glu and Asn, each known to be inhibitors of nitrate uptake. The results showed that GABA treatment induced a significant increase of BnNrt2 mRNA expression, but had less effect on nitrate influx. By contrast, Gln, Glu and Asn significantly reduced nitrate influx and BnNrt2 mRNA expression compared with the control plants. This study provides the first evidence that GABA may act as a putative long‐distance inter‐organ signal molecule in plants in conjunction with negative control exerted by Gln. The up‐regulation effect of GABA on nitrate uptake is discussed in the context of its role in N metabolism, nutritional stress and the recent discovery of a putative role of GABA as a signal molecule in plant development.     

MLB-200型Q-开关Nd:YAG激光治疗雀斑67例疗效观察

本文报道使用MLB－200型Q－开关Nd:YAG激光治疗67例雀斑的疗效。选用532nm波长,光斑直径2－3mm,能量密度6－10J/cm^2,脉冲频率2－5次／秒,光斑重叠不超过10％。术后8周进行第二次治疗,第二次治疗后三个月评定疗效。结果,两次治疗后总痊愈率为92．545,无严重副作用产生。     

外源DNA在体内的吸收与降解

外源ＤＮＡ在动物体内的吸收与降解研究已经受到了关注[1、2 ] 。由于基因治疗与ＤＮＡ疫苗的飞速发展 ,经常要通过一定的方式将外源的ＤＮＡ导入到动物体 ,然而对于它们的吸收与降解机制到目前为止仍然不是十分清楚。用基因治疗疾病时 ,须解决外源基因在动物体内的吸收与降解问题 ,尤其是大量外源ＤＮＡ质粒在动物体内的吸收与降解问题。外源ＤＮＡ的吸收与降解研究已成为一个热点 ,目前主要集中在肠胃道吸收降解和细胞吸收降解两个方面。1 .外源ＤＮＡ在肠胃道中的吸收与降解最有可能让外源ＤＮＡ进入动物体的就是肠胃道 ,在每天的进食中 …