凡纳滨对虾饲料中酵母水解物替代鱼粉适宜比例的研究

试验添加酵母水解物替代不同比例鱼粉, 添加量分别为0(对照组)、2.5%、5.0%、7.5%、10%和12.5%,替代鱼粉的比例分别为0、8%、16%、24%、32%和40%, 通过评估生长性能、消化酶和免疫相关酶活性等指标评价酵母水解物替代鱼粉对凡纳滨对虾健康生长的影响。选择健康凡纳滨对虾[初重(0.630.01) g]随机分为6组, 每组3个重复, 养殖8周。结果表明, Y2.5和Y5.0处理组对虾增重率和特定生长率与Y0相比差异不显著(P0.05), 但是显著高于其余各组(P0.05), Y2.5组饲料系数和Y0组相比差异不显著, 显著低于其余各组(P0.05); Y5.0组肝胰腺糜蛋白酶和Y0组相比差异不显著(P0.05), 显著高于其余各组(P0.05); Y2.5和Y7.5组胰蛋白酶和Y0组相比差异不显著, 但是显著高于其余各组(P0.05); Y2.5组与Y5.0酚氧化酶活性显著高于其余各组(P0.05), Y2.5组与Y7.5组和Y0组总一氧化氮合酶活性显著高于其余各组(P0.05), Y5.0组和Y7.5组血清溶菌酶活性显著高于其余各组(P0.05)。以增重率为判据, 经二次曲线拟合得出, 获得最大增重率时酵母水解物添加量为1.62%, 替代鱼粉比例为5.19%; 酵母水解物替代鱼粉比例达24%时不会对增重率产生显著影响。     

黄颡单尾虫(粘体门,双壳目)的重描述及基于28S rDNA和ITS-5.8S序列的系统地位分析

采用形态分类学方法与以28S rDNA和ITS-5.8S序列为基础的分子系统学研究方法,对采自嘉陵江重庆市磁器口江段的黄颡单尾虫Unicauda pelteobagrusMa,1998进行了形态学和分子生物学的研究。基于28S rDNA数据探讨了黄颡单尾虫以及单尾虫属与相邻种属粘孢子虫间的系统地位;基于5.8S rDNA数据比较分析了粘孢子虫的系统地位。补充了黄颡单尾虫重庆种群形态学信息和28S rDNA、ITS-5.8S rDNA序列的分子信息。     

豌豆蚜触角转录组化学感受蛋白的鉴定、表达和结合特性分析

[目的]本研究旨在鉴定豌豆蚜Acyrthosiphon pisum触角转录组中化学感受蛋白(chemosensory protein,CSP)基因,明确触角中高表达的豌豆蚜CSP蛋白与蚜虫报警信息素、性信息素以及植物挥发物的分子结合特性.[方法]通过对豌豆蚜成蚜触角进行转录组测序,鉴定触角中候选CSP基因;采用RPKM...     

不同浓度复合液体维生素对凹纹胡蜂访问偏好的影响

本研究旨在为配制凹纹胡蜂Vespa uelutina auraria Smith的人工饲料提供基本理论依据。2015年7月20日至7月24日,室外招引凹纹胡蜂,以分别添加了2‰、6‰和10‰复合液体维生素的40%蔗糖溶液作为试验组,相同浓度的蔗糖溶液作为对照,观察其对4组不同食物的访问次数和访问时间。结果表明,凹纹胡蜂对2‰复合液体维生素组访问次数最高,极显著高于对照、6‰和10‰维生素组(P0.01),而对含有10‰复合液体维生素的糖溶液组访问次数最低。此外,凹纹胡蜂访问2‰维生素组和6‰维生素组的时间差异不显著(P0.05),但均极显著高于对照组和10‰维生素组(P0.01)。研究结果表明,凹纹胡蜂对添加了2‰维生素的蔗糖溶液具有显著偏好。     

弗里熊蜂蜜罐中糖液成分分析

【目的】熊蜂是众多植物的重要传粉昆虫,以采集并贮藏花蜜和花粉为主要食物。本研究旨在探究熊蜂的营养需求及明确其对采集的食物是否存在酿制过程。【方法】利用白砂糖溶液(糖浓度50%)饲喂弗里熊蜂Bombus friseanus蜂群,收集并检测其贮藏在蜜罐中1~7 d的糖液,作为处理组样品;同时将上述白砂糖溶液置于灭菌离心管中,排除熊蜂取食,作为对照组样品,测定贮藏期间处理组和对照组糖液的pH值、糖浓度、糖组分及α-淀粉酶和转化酶活性。【结果】弗里熊蜂B. friseanus贮藏在蜜中1~7d的糖液pH值平均为3.74±0.13,显著低于对照组(6.55±0.15);糖浓度与贮藏时间显著正相关,贮藏6d后糖浓度显著高于贮藏1~3 d时的;糖液组分更加丰富,除蔗糖外利用HPLC还检出果糖、葡萄糖、麦芽糖和海藻糖,贮藏4~5 d的糖液中己糖含量极显著高于贮藏1~3 d和6~7 d时的,己糖和麦芽糖含量分别与蔗糖含量极显著负相关,总糖中果糖和麦芽糖含量与贮藏时间极显著负相关,葡萄糖、蔗糖和海藻糖的含量分别与贮藏时间极显著正相关。贮藏6 d的糖液中α-淀粉酶活性显著高于其他时间,其他贮藏时间样品间α-淀粉酶活性差异不显著,而所有样本的转化酶活性在21.17~38.05 U/g FW之间,随贮藏时间的延长差异不显著。【结论】弗里熊蜂B. friseanus采集人工饲喂的糖溶液贮藏在蜜罐中,经其加工后发生了物理和生物化学变化,揭示熊蜂存在酿蜜能力。本研究的结果为熊蜂生物学及繁育研究提供了参考。     

植物铁蛋白与氧化胁迫应激

植物铁蛋白是植物体重要的铁调节蛋白。许多研究表明植物铁蛋白与氧化胁迫抗性之间具有较强关联。植物铁蛋白不仅能抵御高铁产生的氧化毒性,在很多氧化胁迫及环境胁迫抗性中也发挥作用。对植物铁蛋白在氧化及逆境胁迫中的应激加以综述,为铁蛋白在生物工程领域的应用提供理论依据。     

石榴籽中多酚的提取及其抗氧化作用研究

通过正交试验对石榴籽多酚的提取条件及其抗氧化活性(清除DPPH?和还原性)进行了研究.结果表明:(1)石榴籽多酚的最佳提取工艺参数为:乙醇浓度50%、pH值为4、六偏磷酸钠添加量0.4%、温度60℃;(2)石榴籽多酚提取物对DPPH?的清除率达11.34%,还原力达0.73,与VC和VE的抗氧化作用相比,其清除率大小顺序为:VC>石榴籽多酚提取物>VE,还原力大小顺序为:石榴籽多酚提取物>VC>VE,表明石榴籽多酚提取物对DPPH?有较强的清除作用,其还原力强于VC和VE.     

Coarse-grained dynamics of the receiver domain of NtrC: fluctuations, correlations and implications for allosteric cooperativity

Receiver domains are key molecular switches in bacterial signaling. Structural studies have shown that the receiver domain of the nitrogen regulatory protein C (NtrC) exists in a conformational equilibrium encompassing both inactive and active states, with phosphorylation of Asp54 allosterically shifting the equilibrium towards the active state. To analyze dynamical fluctuations and correlations in NtrC as it undergoes activation, we have applied a coarse-grained dynamics algorithm using elastic network models. Normal mode analysis reveals possible dynamical pathways for the transition of NtrC from the inactive state to the active state. The diagonalized correlation between the inactive and the active (phosphorylated) state shows that most correlated motions occur around the active site of Asp54 and in the region Thr82 to Tyr101. This indicates a coupled correlation of dynamics in the "Thr82-Tyr101" motion. With phosphorylation inducing significant flexibility changes around the active site and alpha3 and alpha4 helices, we find that this activation makes the active-site region and the loops of alpha3/beta4 and alpha4/beta5 more stable. This means that phosphorylation entropically favors the receiver domain in its active state, and the induced conformational changes occur in an allosteric manner. Analyses of the local flexibility and long-range correlated motion also suggest a dynamics criterion for determining the allosteric cooperativity of NtrC, and may be applicable to other proteins.     

The base of the Middle Ordovician in China with special reference to the succession at Hengtang near Jiangshan, Zhejiang Province, southern China

Extensive work during the last decade has led to the recent decision by the International Subcommission on Ordovician Stratigraphy that the base of the Middle Ordovician Series should be placed at the base of the Baltoniodus triangularis Conodont Biozone in the Huanghuachang GSSP (Global Stratotype Section and Point) section near Yichang, Hubei Province, China. A review of the biostratigraphy of successions in many parts of China shows that for various reasons, it is currently difficult to recognize the precise boundary level in many regions, and additional studies are clearly needed. A newly exposed, previously poorly known, condensed section in deeperwater facies at Hengtang near Jiangshan in the Chiangnan (Jiangnan) belt has yielded a substantial number of important graptolites and conodonts through the boundary interval. It provides a more informative illustration of the relations between the ranges of several key taxa of these groups than any other section in China, and the level of the base of the Middle Ordovician appears to be within an about 1.8 m thick interval of Ningkuo Formation, and lies in the lower Isograptus caduceus imitatus Biozone.     

New fossil Ochteridae (Hemiptera: Heteroptera: Ochteroidea) from the Upper Mesozoic of north‐eastern China,with phylogeny of the family

Specimens of the velvety shore bugs (Hemiptera: Ochtheridae) occur in the Early Cretaceous Yixian Formation in north‐eastern China. We describe two new genera and three new species –Pristinochterus ovatus Yao, Zhang & Ren sp. nov., Floricaudus multilocellus Yao, Ren & Shih gen.n. et sp.n. and Angulochterus quatrimaculatus Yao, Zhang & Ren gen.n. et sp.n. – from this deposit. A cladistic analysis based on a combination of fossil and extant taxa, and their morphological characters, clarifies the phylogenetic status of the new fossils and allows the reconstruction of relationships within the family Ochteridae. Two main clades within Ochteridae are recognized from the cladistic analysis: Pristinochterus Yao Cai & Ren and Floricaudus Yao, Ren & Shih gen.n. form a monophyletic lineage; and Angulochterus Yao, Zhang & Ren gen.n. emerges as a sister group to all extant velvety shore bugs. A key to all fossil and extant genera of Ochteridae is provided.