鲢快速逃逸游泳行为研究

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The altered activity of complex III may contribute to the high penetrance of Leber's hereditary optic neuropathy in a Chinese family carrying the ND4 G11778A mutation

The ND4 G11778A mutation is the most common mitochondrial DNA mutation leading to Leber's hereditary optic neuropathy (LHON). Despite considerable clinical evidences, the modifier role of nuclear background and mitochondrial haplotypes in phenotypic manifestation of LHON remains poorly understood. We investigated the effect of these modifiers on bioenergetics in lymphoblastoid cell lines derived from five affected subjects of one Chinese family carrying the G11778A mutation and five Chinese controls. Significant reductions in the activities of complexes I and III were observed in mutant cell lines from the Chinese family, whereas the mutant cell lines from other families carrying the same mutation exhibited only reduced activity of complex I. The reduced activities of complexes I and III caused remarkably higher reductions of ATP synthesis in mutant cell lines from the Chinese family than those from other families. The deficient respiration increased generation of reactive oxygen species. The defect in complex III activity, likely resulting from the mitochondrial haplotype or nuclear gene alteration, worsens mitochondrial dysfunction caused by the G11778A mutation, thereby causing extremely high penetrance and expressivity of optic neuropathy in this Chinese family. Our data provide the first experimental evidence that altered activity of complex III modulates the phenotypic manifestation of LHON-associated G11778A mutation. Thus, our findings may provide new insights into the pathophysiology of LHON.     

普氏蹄蝠下丘谐波内外神经元处理多普勒频移补偿信息的差异

为了探讨普氏蹄蝠下丘神经元在处理多普勒频移补偿后回声定位信号中的作用,实验采用双声刺激模式模拟蝙蝠不同飞行状态下产生多普勒频移补偿后的脉冲-回声对,即发声频率改变,回声频率维持恒定的情况下,研究下丘神经元对不同补偿值下的回声反应恢复率.结果发现:根据神经元在某一补偿值下对回声信号反应的恢复率是否超过70%,可将其分为具有选择性(S)和无选择性(NS)的两类神经元.且谐波内S神经元所占比例(68%)远超过非谐波内S神经元(39%).分析神经元的发放模式发现谐波内S神经元中相位型发放模式比例(44.3%)明显高于其他三种类型神经元.另外,虽然S和NS神经元的强度-潜伏期函数类型均以饱和型为主,但谐波内S神经元强度-潜伏期函数的最佳强度(best amplitude,BA)(95.3±14.0)dB SPL低于NS神经元的BA(104.1±10.2)d B SPL(P0.01),同时也低于非谐波内S神经元的BA(109.7±7.9)dB SPL(P0.01).以上实验结果表明,在下丘水平,神经元就已对多普勒频移补偿后回声定位信号的处理有了分工,集中在谐波内的S神经元通过提高对某一补偿值下回声信号反应的恢复率实现,对回声信息的精确编码,避免其他杂波干扰信息.同时,谐波内S神经元的发放模式和强度-潜伏期函数特点也满足其在复杂环境中精确声学成像的需求.     

草鱼血液学的研究 Ⅰ.九项血液常数的周年变化

用741尾健康草鱼种作红细胞、血红蛋白、红细胞比积、红细胞平均体积、红细胞平均血红蛋白量、红细胞平均血红蛋白浓度、红细胞沉降率、血浆总蛋白和血浆葡萄糖浓度等九项血液常数的测定。所得的年均值经变异系数分析,除红细胞沉降率和血浆葡萄糖浓度外,其余各项常数的可靠性基本一致。另从周年变动的规律分析,高值出现在冬夏季,低值出现的月份较为分散。水温仅对总蛋白含量的变动呈现显著的负相关(P<0.01)。而体重与血液常数存在着一定的相关因素,在10—90克之间的鱼种中,血红蛋白、红细胞比积、红细胞平均体积、红细胞平均血红蛋白量与体重呈现直线正相关;红细胞沉降率为负相关。     

Wangella harbinensis gen. nov., sp. nov., a new member of the family Micromonosporaceae

A novel endophytic actinomycete, designated strain NEAU-J3^T, was isolated from soybean root (Glycine max (L.) Merr) and characterized using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain NEAU-J3^T fell within the family Micromonosporaceae. The strain was observed to form an extensively branched substrate mycelium, which carried non-motile oval spores with a smooth surface. The cell walls of strain NEAU-J3^T were determined to contain meso-diaminopimelic acid and galactose, ribose and glucose were detected as whole-cell sugars. The major menaquinones were determined to be MK-9(H₄) and MK-9(H₆). The phospholipids detected were phosphatidylcholine and phosphatidylethanolamine. The major cellular fatty acids were determined to be C_16:0, C_18:1 ω9c, C_18:0, C_17:0, C_17:1 ω7c, anteiso-C_17:0, C_16:1 ω7c and C_15:0. The DNA G + C content was 62.5 mol%. On the basis of the morphological and chemotaxonomic characteristics, phylogenetic analysis and characteristic patterns of 16S rRNA gene signature nucleotides, strain NEAU-J3^T is considered to represent a novel species of a new genus within the family Micromonosporaceae, for which the name Wangella harbinensis gen. nov., sp. nov. is proposed. The type strain of Wangella harbinensis is strain NEAU-J3^T (=CGMCC 4.7039^T = DSM 45747^T).     

Oxygen binding and oxidation reactions of human hemoglobin conjugated to carboxylate dextran

Human hemoglobin (Hb) conjugated to benzene tetracarboxylate substituted dextran produces a polymeric Hb (Dex-BTC-Hb) with similar oxygen affinity to that of red blood cells (P(50)=28-29 mm Hg). Under physiological conditions, the oxygen affinity (P(50)) of Dex-BTC-Hb is 26 mm Hg, while that of native purified human HbA(0) is 14 mm Hg, but it exhibits a slight reduction in cooperativity (n(50)), Bohr effect, and lacks sensitivity to inositol hexaphosphate (IHP), when compared to HbA(0). Oxygen-binding kinetics, measured by rapid mixing stopped-flow method showed comparable oxygen dissociation and association rates for both HbA(0) and Dex-BTC-Hb. The rate constant for NO-mediated oxidation of the oxy form of Dex-BTC-Hb, which is governed by NO entry to the heme pocket, was reduced to half of the value obtained for HbA(0). Moreover, Dex-BTC-Hb is only slightly more sensitive to oxidative reactions than HbA(0), as shown by about 2-fold increase in autoxidation, and slightly higher H(2)O(2) reaction and heme degradation rates. Dextran-BTC-based modification of Hb produced an oxygen-carrying compound with increased oxygen release rates, decreased oxygen affinity and reduced nitric oxide scavenging, desirable properties for a viable blood substitute. However, the reduction in the allosteric function of this protein and the lack of apparent quaternary T-->R transition may hinder its physiological role as an oxygen transporter.     

中国水仙(Narcissus tazetta var.chinensis)的组织培养

以栽培的中国水仙Narcissus tazetta var.Chinensis鳞茎为实验材料,采取“无液处理”的简捷方法获取外植体,并筛选出中国水仙离体鳞茎培养的最佳培养基。     

稻米垩白形成的气象生态基础研究

在全国13个点、19个品种多播期试验基础上,对稻米垩自形成的气象生态基础进行了分析。结果表明,水稻齐穗后15天的日均温是影响稻米垩白大小的主要气象因子。经对稻米垩白与齐穗后15天内均温关系的动态分析可知,稻米垩白随该时段温度提高而增大的拐点温度约为29℃(品种间略有差异),接近或超过该点温度,稻米垩白会突发性地增加。     

能源植物甜高粱种质资源和分子生物学研究进展

世界能源危机和全球生态环境日益恶化迫使人们急需开发可再生能源。生物质能源作为一种清洁的可再生能源已受到世界各国的高度重视。发展生物质能源的瓶颈之一是生物质原料不足。甜高粱的生物学产量和含糖量极高, 同时兼有耐旱、耐涝、耐贫瘠和耐盐碱等诸多优良特性, 被认为是最具开发潜力的能源植物之一。该文从甜高粱的分类学、生物学特点、种质资源评价、功能基因以及基因组信息等方面综述了甜高粱的最新研究进展和存在的问题, 并展望了甜高粱作为能源植物的研发前景。     

植物中钙依赖蛋白激酶(CDPKs)的结构与功能

在植物细胞中,钙离子作为第二信使,通过钙依赖蛋白激酶（CDPKs）发挥功能是其传递信号的主要途径之一。CDPKs广泛存在于植物体内,是目前植物体内研究最深入的蛋白激酶。在简要阐述CDPKs于植物体内的分布定位的基础上,介绍了CDPKs的结构特点、生化性质及其在植物细胞生理功能中的作用,并就该领域的研究前景作了展望。