不同着色剂对孔雀鱼雌鱼生长和体色的影响

试验通过在基础饲料中添加叶黄素(200 mg·kg-1)、虾青素(200 mg·kg-1)和维生素A(30 000 IU·kg-1)+维生素E(200 mg·kg-1)饲养平均体质量为0.46±0.02 g的孔雀鱼雌鱼40 d,研究不同着色剂对尾鳍为橘红色的孔雀鱼雌鱼体色的影响.研究结果表明:不同着色剂对孔雀鱼雌鱼的质量相对增加率、饲料效率和存活率无显著影响(P>0.05);饲料中添加叶黄素和添加虾青素时,孔雀鱼雌鱼的尾鳍R值强度显著低于对照组;饲料中同时添加维生素A和维生素E时,R值强度与对照组无显著差异(P>0.05);不同组别的G值和B值强度都没有显著差异(P>0.05).     

松材线虫体表物质与其携带细菌的关系

松萎蔫病是由松材线虫与其所携带的细菌复合侵染所引起。为进一步明确松材线虫与其携带细菌的关系,笔者用无菌线虫体表浸泡物处理细菌,再将无菌线虫各虫株与细菌共培养,结果表明细菌的存在可促进线虫的繁殖,线虫体表浸泡物质可促进细菌繁殖,无菌线虫与细菌共培养后线虫繁殖数量较无菌线虫单独培养有明显增加,说明松材线虫与其体表细菌的关系为一种互惠关系。此外还设计了无菌线虫对细菌的趋向性试验,考察线虫与自身体表所携带细菌之间的趋向性是否具有特异性,结果表明所有无菌线虫对成团泛菌具有明显的趋向性,各无菌松材线虫对于分离自各自体表的细菌菌株没有特异的趋向性。     

敦化泥炭矿物质组成的研究

选取敦化大桥和哈尔巴岭两个泥炭剖面，在实验室测定了泥炭矿物质组成及其剖面变化情况，并与吉林省东部其他泥炭剖面进行对比。结果显示：泥炭灰分含量远远低于同一剖面其下部矿质土的灰分含量；同一地区、同一成炭植物类型，因成矿类型不同，灰分含量有差异；与其他地区泥炭相比，敦化泥炭属于中等偏低灰分泥炭；灰成分中Na2O含量偏高。     

Met- and Leu-enkephalin immunoreactivity in separate neurones.

A pair of pentapeptides, Met- and Leu-enkephalin were recently isolated from brain tissue. The two peptides seem to represent endogenous opiate receptor ligands and have by immunocytochemical and radioimmunoassay studies been shown to occur in an extensive system of cerebral and peripheral nerves. The relative proportions between Met- and Leu-enkephalin varies between different brain regions and also between different species, suggesting the existence of separate populations of Met- and Leu-enkephalin nerves. Until now, however, immunocytochemistry has given no support for this notion. We report here evidence of separate populations of Met- and Leu-enkephalin nerves.     

榆紫叶甲 Ambrostoma quadriim-pressum脑及咽下神经节GABA阳性神经元分布模式的构建

采用树脂石蜡(CP)组织包埋切片技术,结合免疫组化链霉菌抗生物素蛋白-过氧化物酶(SP)双染法,初步构建了榆紫叶甲脑及咽下神经节GABA阳性神经元的分布模式.结果显示,榆紫叶甲脑结构比较特殊:视叶不发达,但具内髓板;嗅叶不发达;蕈形体冠高度退化,而根叶相对发达;中央复合体结构明显;后脑经由围咽神经束与咽下神经结相连,咽下神经结非常发达.榆紫叶甲的所有髓区几乎都有GABA免疫阳性纤维分布.一侧脑半球及咽下神经节共存在约2 800个GABA阳性神经元,分布广泛,且趋向于集群分布.该研究表明榆紫叶甲的脑结构及GABA阳性神经元的分布模式与榆紫叶甲的生活习性、进化地位等密切相关.     

车身骨架刚度与改进分析

由于客车车身刚度是评价客车车身性能的一项重要指标,因此,文章采用梁体混合模型的方法,建立了一款半承载式客车的有限元模型。利用有限元方法分析了客车车身在不同工况下的刚度,通过静态刚度的分析,对客车中门进行了改进,并为整个车身结构的优化提供了依据。     

GABA and GAD immunoreactivity of photoreceptor terminals in primate retina

Within the vertebrate retina, two types of photoreceptor cells--the rods and cones--transduce visual signals and convey this information through synapses with bipolar and horizontal cells. Although the neurotransmitter at these first-order synapses has not been identified, electrophysiological studies suggest that it might be excitatory. In the present study, however, we have found photoreceptor terminals in the rhesus monkey retina which are immunoreactive with antibodies to either gamma-aminobutyric acid (GABA) or L-glutamic acid decarboxylase (GAD, an enzyme involved in the synthesis of GABA). In the perifoveal region of the retina, approximately 25% of presynaptic profiles having ultrastructural characteristics of either rod or cone terminals are immunoreactive with one or the other antibody. This evidence for a putatively inhibitory neurotransmitter in photoreceptor terminals challenges present understanding of retinal synaptic function.