不同生长阶段青枯菌的高效离子交换色谱表征

采用高效离子交换色谱和激光光散射仪对不同生长阶段的青枯菌进行色谱表征。青枯菌经过色谱分离得到3个特征峰。通过对延滞期、对数生长期和稳定期青枯菌细胞浓度、发酵液pH值、细胞表面黏附的胞外酸性多糖(EPSⅠ)含量与青枯菌色谱行为的关系研究,发现在8h时,青枯菌运动能力强,细胞表面EPSⅠ少,吸附力弱,绝大多数菌体直接随流动相流出形成峰1;随着培养时间延长,细胞表面黏附的EPSⅠ量增多,与树脂吸附力增强,保留时间延长。因此分析3个色谱峰的形成与青枯菌的运动性、以及细胞表面EPSⅠ与阴离子交换树脂的吸附作用有关。并通过比较3个色谱峰青枯菌细胞表面EPSⅠ含量的差异和观察青枯菌经过4%甲醛固定处理后色谱行为的变化加以进一步验证。高效离子交换色谱为细菌完整细胞的研究提供了一种新的分析方法。     

银耳二型态细胞差异性的初步研究

以银耳的担孢子、节孢子和菌丝体为材料,通过显微观察和电泳分析揭示银耳二型态细胞间的差异性。显微形态及核相观察表明:节孢子直径略大于担孢子,担孢子为单核细胞,节孢子绝大多数为单核细胞,少数为双核细胞,菌丝体为双核细胞并具有典型的锁状联合结构。总蛋白及同工酶电泳分析表明:菌丝相总蛋白谱带多于酵母相,过氧化物及酯酶与酵母相存在一定差异,而多酚氧化酶基本相同。因此,伴随银耳二型态细胞两相形态的转变,细胞代谢水平发生了相应变化。     

Generation of Food-Grade Recombinant Lactic Acid Bacterium Strains by Site-Specific Recombination

The construction of a delivery and clearing system for the generation of food-grade recombinant lactic acid bacterium strains, based on the use of an integrase (Int) and a resolvo-invertase (β-recombinase) and their respective target sites (attP-attB and six, respectively) is reported. The delivery system contains a heterologous replication origin and antibiotic resistance markers surrounded by two directly oriented six sites, a multiple cloning site where passenger DNA could be inserted (e.g., the cI gene of bacteriophage A2), the int gene, and the attP site of phage A2. The clearing system provides a plasmid-borne gene encoding β-recombinase. The nonreplicative vector-borne delivery system was transformed into Lactobacillus casei ATCC 393 and, by site-specific recombination, integrated as a single copy in an orientation- and Int-dependent manner into the attB site present in the genome of the host strain. The transfer of the clearing system into this strain, with the subsequent expression of the β-recombinase, led to site-specific DNA resolution of the non-food-grade DNA. These methods were validated by the construction of a stable food-grade L. casei ATCC 393-derived strain completely immune to phage A2 infection during milk fermentation.     

松树蜂与其共生真菌的互利共生关系

松树蜂Sirex noctilio Fabricius是一种重要的国际林业检疫性害虫,主要危害针叶树,原产欧亚大陆和北非。近100多年来,先后入侵大洋洲(新西兰和澳大利亚)、南美洲(乌拉圭、阿根廷、巴西和智利)、北美洲(加拿大和美国),以及南非。2013年8月,在中国黑龙江省内首次发现松树蜂,目前发现其主要危害樟子松。松树蜂能与一种淀粉韧革菌属Amylostereum的真菌Amylostereum areolatum(Fr.)Boidin形成严格的互利共生关系,该虫除直接钻蛀树木外,还能通过产卵行为将自身毒素腺体分泌的毒素和体内共生真菌随同虫卵一起注入寄主树木体内,形成"虫-毒-菌"3个致害因子相互协作的特殊危害方式,加速树势的衰弱并造成寄主树木死亡。本文就国内外松树蜂与其共生菌互利共生关系的研究进行了综述,分别从结构与功能的层次上对其互利共生关系进行了梳理和总结,重点阐释了松树蜂与共生菌的营养共生关系,松树蜂携带传播共生菌的机制,共生菌的种群遗传学以及松树蜂毒素和共生菌在危害寄主树木时的协同关系等。以期为开展关于松树蜂的专项研究提供一些合理的建议,同时为积极有效地防控该害虫提供科学依据。     

Hsp70-NP融合蛋白增强诱导HTNV NP特异性CTL的实验研究

本文采用纯化蛋白Hsp70-NP,NP,Hsp70分别免疫C57/BL6小鼠,取各组小鼠脾淋巴细胞进行淋巴细胞增殖试验和细胞毒试验.此外,为了获得细胞毒实验的靶细胞,本文还采用脂质体介导质粒pcDNA3.1/S转染黑色素瘤细胞B16,通过G418筛选稳定克隆,并用RT-PCR,Western blots以及免疫荧光染色证实N蛋白在胞浆中表达.淋巴细胞增殖实验表明,Hsp70-NP,NP组小鼠脾淋巴细胞均能够对体外抗原刺激产生增殖反应,而Hsp70-NP组的增殖指数明显高于NP免疫组.细胞毒实验结果表明,LDH的释放具有效应细胞依赖性,Hsp70-NP,NP免疫组脾淋巴细胞均可以特异性杀伤靶细胞B16-N,而Hsp70-NP免疫组的杀伤率显著高于NP免疫组.实验结果显示,Hsp70可以增强NP诱导产生特异性CTL的能力.本研究结果为进一步设计基于NP的合成肽疫苗或基因疫苗提供了重要实验依据.     

Assessing the impact of extreme adverse weather on the biological traits of a European storm petrel colony

Climate change affects the climatic disturbance patterns and regimes and is altering the frequency and intensity of subtropical cyclones. These events can affect population dynamics of seabirds (e.g., survival, reproduction). In this work we tested the effect of adverse weather on a colony of European storm petrels (Hydrobates pelagicus) located in a small islet (Aketx) in northern Spain. Over a long-term monitoring period (1993–2014) we ringed 3728 petrels. From 2003 onwards we also monitored breeding success, the percentage of immature individuals and moult scores. We used Cormack-Jolly-Seber models and Underhill and Zucchini models to analyze the effects of climatic conditions on a number of biological traits (survival, breeding parameters, moulting patterns). Our analyses revealed a constant value of adult survival over the 26-year monitoring period. Recapture probability, however, tended to be positively influenced by NAO conditions in spring, and negatively influenced by NAO conditions in winter (although this would only affect to a fraction of first-captured birds). Moreover, the impact of adverse weather, especially in 2011 and 2014, resulted in an increasing proportion of yearlings in the breeding population, a lower breeding success and a delayed onset of moult. These effects were similar to those observed during the Prestige oil spill catastrophe.     

Feather mites (Acari: Astigmata) and body condition of their avian hosts: a large correlative study

Feather mites are arthropods that live on or in the feathers of birds, and are among the commonest avian ectosymbionts. However, the nature of the ecological interaction between feather mites and birds remains unclear, some studies reporting negative effects of feather mites on their hosts and others reporting positive or no effects. Here we use a large dataset comprising 20 189 measurements taken from 83 species of birds collected during 22 yr in 151 localities from seven countries in Europe and North Africa to explore the correlation between feather mite abundance and body condition of their hosts. We predicted that, if wing‐dwelling feather mites are parasites, a negative correlation with host body condition should be found, while a mutualistic interaction should yield positive correlation. Although negative relationships between feather mite abundance and host body condition were found in a few species of birds, the sign of the correlation was positive in most bird species (69%). The overall effect size was only slightly positive (r =0.066). The effect of feather mite abundance explained <10% of variance in body condition in most species (87%). Results suggest that feather mites are not parasites of birds, but rather that they hold a commensalistic relationship where feather mites may benefit from feeding on uropygial gland secretions of their hosts and birds do not seem to obtain a great benefit from the presence of feather mites.     

Amino acid sequence and homology modeling of obtustatin,a novel non-RGD-containing short disintegrin isolated from the venom of Vipera lebetina obtusa

Disintegrins represent a group of cysteine-rich peptides occurring in Crotalidae and Viperidae snake venoms, and are potent antagonists of several integrin receptors. A novel disintegrin, obtustatin, was isolated from the venom of the Vipera lebetina obtusa viper, and represents the first potent and selective inhibitor of the binding of integrin alpha(1)beta(1) to collagen IV. The primary structure of obtustatin contains 41 amino acids and is the shortest disintegrin described to date. Obtustatin shares the pattern of cysteines of other short disintegrins. However, in contrast to known short disintegrins, the integrin-binding loop of obtustatin is two residues shorter and does not express the classical RGD sequence. Using synthetic peptides, a KTS motif was identified as the integrin-binding sequence. A three-dimensional model of obtustatin, built by homology-modeling structure calculations using different templates and alignments, strongly indicates that the novel KTS motif may reside at the tip of a flexible loop.     

Proteomic analysis of microvesicles from plasma of healthy donors reveals high individual variability

Healthy blood plasma is required for several therapeutic procedures. To maximize successful therapeutic outcomes it is critical to control the quality of blood plasma. Clearly initiatives to improve the safety of blood transfusions will have a high economical and social impact. A detailed knowledge of the composition of healthy blood plasma is essential to facilitate such improvements. Apart from free proteins, lipids and metabolites, blood plasma also contains cell-derived microvesicles, including exosomes and microparticles from several different cellular origins. In this study, we have purified microvesicles smaller than 220nm from plasma of healthy donors and performed proteomic, ultra-structural, biochemical and functional analyses. We have detected 161 microvesicle-associated proteins, including many associated with the complement and coagulation signal-transduction cascades. Several proteases and protease inhibitors associated with acute phase responses were present, indicating that these microvesicles may be involved in these processes. There was a remarkably high variability in the protein content of plasma from different donors. In addition, we report that this variability could be relevant for their interaction with cellular systems. This work provides valuable information on plasma microvesicles and a foundation to understand microvesicle biology and clinical implications.