初生赛加羚羊部分生物学指标的观测与分析

2018年4月下旬至5月初对国家林业局甘肃濒危动物保护中心的61只初生赛加羚羊(Saiga tatarica)成活率、性别比例、单双羔比例、初生重等生物学数据进行了观测,并对结果进行归纳分析。赛加羚羊分娩期始于4月25日,截止于5月5日,产羔高峰期集中在4月28日至5月2日。共分娩61只羔羊,成活56只,成活率91.80%。其中,雄性羔羊占40.98%,雌性羔羊占59.02%,雌雄性别比(♀︰♂)为1.44︰1,与1︰1的性比差异不显著(χ2检验,P> 0.05);单羔比例80.33%,双羔比例19.67%,两者差异极显著(P <0.01);初生羔羊体重多数集中在2.501～3.000 kg,雄性羔羊平均初生重略高于雌性羔羊,单羔羚羊平均体重略高于双羔羚羊。单羔雄羚羊与双羔雄羚羊、单羔雌羚羊与双羔雌羚羊以及单双羔、雌雄羔羊总平均体重间的差异均不显著(P> 0.05)。     

Extremely low levels of genetic diversity in the terrestrial orchid Epipactis thunbergii (Orchidaceae) in South Korea: implications for conservation

Levels of allozyme variation, population genetic structure, and fine-scale genetic structure (FSGS) of the rare, both sexually and clonally reproducing terrestrial orchid Epipactis thunbergii were examined for eight ( N  = 734) populations in a 20 × 20-km area in South Korea. Twenty-three putative allozyme loci resolved from 15 enzyme systems were used. Extremely low levels of allozyme variation were found within populations: the mean frequency of polymorphic loci was 3.8% [isocitrate dehydrogenase ( Idh-2 ) with two alleles was polymorphic across populations], the mean number of alleles per locus was 1.04, and the mean expected heterozygosity was 0.013. The overall fixation index was not significantly different from zero ( F _IS = 0.069), although the species is self-compatible. However, a significantly high degree of population differentiation was found between populations at Idh-2 ( F _ST = 0.388) in the studied area. Furthermore, spatial autocorrelation analyses revealed a significant FSGS (up to 3 m) within populations. These observations suggest that the main explanatory factors for the extremely low levels of genetic diversity and the shaping of the population genetic structure of E. thunbergii are genetic drift as a result of a small effective population size, a restricted gene flow, and the isolation of populations. Considering the current genetic structure of E. thunbergii , three guidelines are suggested for the development of conservation strategies for the species in South Korea: (1) protection of habitats of standing populations; (2) prohibition by law of any collection of E. thunbergii ; and (3) protection of nearby pollinator populations, given the fact that fruit set in natural habitats is very low.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 161–169.     

酰基高丝氨酸内脂合成酶LasI对禽致病性大肠杆菌生物学特性的影响

【背景】禽致病性大肠杆菌(Avian pathogenic Escherichia coli, APEC)是禽类主要病原菌之一,群体感应(Quorumsensing,QS)系统可通过信号分子调控其生物学特性。在APEC中信号分子AHL对其生物学特性的影响目前尚不清楚。【目的】研究信号分子AHL对APEC生物学特性的影响。【方法】将含铜绿假单胞菌酰基高丝氨酸内脂合成酶(Acyl-homoserine-lactone synthase,lasI)基因的表达质粒转化至APEC菌株DE17中,构建重组菌株DE17-lasI,利用LasI在DE17中合成AHL。比较野生株和重组菌株产生AHL信号分子、生长特性、生物被膜形成能力、运动性以及耐药性等生物学特性的差异;运用Real-timePCR技术,比较野生株和重组菌株中与生物被膜形成、运动性以及毒力因子相关基因的转录水平。【结果】对重组菌株AHL信号分子检测表明,DE17-lasI能够产生AHL信号分子,与野生株DE17相比,DE17-lasI生物被膜形成能力和运动性显著降低(P0.01),但其生长特性和耐药性无显著变化(P0.05);Real-time PCR检测结果表明,重组菌株的毒力因子fimH转录水平上调了58.8倍,而ompA、iss分别下调了95.4%、77.3%。与生物被膜形成相关基因agn43下调了75%,鞭毛合成基因flhA下调了80.8%。此外,AHL受体sdiA的转录水平上调了19.8倍。【结论】转化lasI至APEC中,能促进其在APEC中合成信号分子AHL,并显著影响APEC的部分生物学特性,为进一步探讨AHL型群体感应系统对APEC的调控作用提供参考。     

转mapk双链RNA干扰表达载体黄瓜对根际土壤细菌多样性的影响

随着RNA干扰技术的发展,通过植物表达病原物特异的dsRNA来防治植物病害的转基因作物越来越多.转根结线虫mapk双链RNA表达载体的黄瓜能够通过RNA干扰作用沉默线虫的mapk基因,对根结线虫具有良好的防治效果.为了评价该转基因黄瓜的安全性,明确mapk双链RNA干扰表达载体转基因黄瓜植株对根际土壤细菌多样性的影响,采用16S rRNA基因克隆文库方法对非转基因黄瓜和转基因黄瓜土壤细菌群落多样性进行分析.结果表明,非转基因黄瓜土壤细菌文库包含124个OTU(可操作分类单元),转基因黄瓜土壤细菌文库包含122个OTU.2个文库共同拥有的OTU为115个.2个文库都包含1 3个类群细菌,Acidobacteria、Actinobacteria、Armatimonadetes、Bacteroidetes、candidate division BRC1、Chloroflexi、Firmicutes、Gemmatimonadetes、Nitrospira、Planctomycetes、Proteobacteria、Verrucomicrobia、unclassified_Bacteria. 其中 Proteobacteria、Bacteroidetes 、Chloroflexi和Acidobacteria是优势菌群.其他细菌类群数量相对较少.在纲分类水平上,两个文库包含的细菌类群一致,且各类群细菌比例差异不大.在Acidobacteria门中,Acidobacteria_Gp6为优势菌群.在Bacteroidetes门中,Sphingobacteria纲细菌数量最多.在Chloroflexi门中,unclassified Chloroflexi细菌最多.在Proteobacteria门中,其中Betaproteobacteria纲的细菌数量最多.从多样性指数角度分析,两种土壤细菌群落的Shannon、Simpson和Chao值差异不大.总体来看,两种土壤细菌类群差异不显著,转基因黄瓜未对根际土壤细菌群落产生明显影响.     

西藏札达及米林发现噪鹃

正在开展西藏第二次陆生野生动物资源调查工作过程中,于2015年6月18日在西藏自治区札达县底雅乡底雅村(31°46′55.5″N,78°52′5.1″E,海拔2 977 m)观察并拍摄到1只雄性噪鹃(Eudynamys scolopaceus)。另一组调查人员曾于2015年5月1日在西藏自治区林芝市米林县羌纳乡岗嘎村遮磨岗(29°18′28.15″N,94°21′44.23″E,3 000 m)听到过噪鹃的叫声。     

干旱胁迫下新疆杨树冠不同高度叶片水分状况与非结构性碳动态北大核心CSCD

水力结构调整及非结构性碳动态对于认知干旱胁迫下植物生存前景和死亡风险至关重要。该研究以新疆杨(Populus bolleana Lauche.)为对象,通过干旱处理分析树冠不同高度叶片水力性状、光合生理特性、不同功能器官间的可溶性糖、淀粉及非结构性碳水化合物(NSC)含量变化,以甄别树冠不同高度叶片对干旱胁迫的生理响应和适应差异。结果表明:(1)在干旱胁迫下,树冠上部的叶水势、叶含水量、枝条含水量普遍低于下部,饱和膨压渗透势及膨压损失点水势在不同树冠高度间差异不显著;(2)干旱处理组植株净光合速率随树冠高度的增加而降低,叶绿素SPAD值在树冠的上部显著低于下部,而水分利用效率在树冠的上部却高于下部;(3)干旱处理组比叶面积在各树冠高度下显著低于对照组,而胡伯尔值在中部及上部高于对照组但差异不显著;(4)干旱处理组,树冠上部叶片淀粉含量显著高于下部,枝条可溶性糖及NSC含量在树冠上部显著高于下部,韧皮部的可溶性糖、淀粉及NSC含量在不同树冠高度间无显著差异,细根的可溶性糖、淀粉及NSC含量在对照组与干旱处理组间的差异不显著。研究发现,干旱处理下,树冠高度的增加会加剧新疆杨枝叶的干旱胁迫,致使树冠上部枝条木质部发生栓塞的风险大于下部,并导致NSC在不同器官间的分配和组分产生差异,但新疆杨植株可通过水分利用效率和形态上的适应性调整减缓干旱胁迫。     

喷雾干燥制备高纯α-亚麻酸微胶囊研究

本文采用喷雾干燥法制备高纯α-亚麻酸为芯材、亚麻籽胶为壁材的微胶囊,并以微胶囊化效率和含油率为指标,考察了制备工艺.结果表明,最佳微胶囊原料配方为:芯材与壁材的比例为(m/m)3∶2,料液浓度为5％,进料温度为20℃;最佳喷雾干燥工艺条件:进风温度为180℃,出风温度为80℃,雾化器转速21000 rpm,进料速度为42.01 mL/min.在此工艺条件下亚麻酸的微胶囊化效率为96.18％,含油率为60.09％.     

The development of plant-parasitic nematode infestations on micro-propagated banana plants following field control measures in Côte d'Ivoire

Of the weeds that were found in banana production areas, only Asystasia gangetica was parasitised by Radopholus similis; Helicotylenchus multicinctus and Hoplolaimus pararobustus were able to parasitise all weed species. Field trials were carried out in Cote d'Ivoire to assess the potential for using nematode-free micro-propagated banana plants following cultural and chemical methods for nematode control. Banana (Musa acuminata) cv. Poyo was examined for nematodes after weed fallow, flooding and chemical treatment. Before replanting bananas, nematode assays showed that: i) all nematode species declined but were not eliminated after a 1,3-dichloropropene soil treatment; ii) H. multicinctus, H. pararobustus and Cephalenchus emarginatus were still present after either a 2-year weed fallow (dominated by Chromolaena odorata or Asystasia gangetica) or a 10-week flooding; iii) R. similis did not persist after fallowing or flooding. All nematode species were found in plots treated with 1,3-dichloropropene and that had been planted with bullheads, suckers or nematode-free micropropagated plants. After both fallow and flooding, R. similis was reintroduced on infested planting materials (bullheads and suckers) even when they were pre-treated with a nematicide. When fallow and flooded plots were planted with nematode-free materials (vitro-plants), R. similis did not appear in the roots for two vegetative cycles. The other species, still present in the soil, invaded the roots and increased slowly in numbers. These results were confirmed in commercial banana plantations.