武威地区天然草地有毒植物及其防除

对武威地区天然草地有毒植物的种类，分布及其对草地的危害情况进行了调查研究，结果表明，全区天然草地共有毒植物１７２号，分属３１科８４属，平均２．１５种／ｍ＾２，盖度达４．４１％地上部分生物量１１．２８ｇ／ｍ＾２。对草地危害的主要黄花棘豆，甘肃棘豆，小花棘豆，狼毒和马草，受侵害的草地主要是山地草甸和山地草原，通过分析，提出了有毒植物防除和利用的建议。     

试论农业工程在全面建设小康社会中的作用

该文在介绍农业工程技术内涵的基础上,论述了农业工程在我国全面建设小康社会的中的作用,作者认为农业工程是我国产业结构调整的重要依据,是信息技术应用的广阔天地,是生物技术转化为社会生产力的工程手段,是提高农民素质的技术依托,是我国全面建设小康社会,解决"三农"问题的技术关键.并由此提出了发展农业工程事业的几点建议1)农业工程从业人员充分珍惜本学科在我国全面建设小康社会中的历史作用;2)加速研究开发和集成组装生态的和经济的农业工程适用技术; 3)以农业工程适用技术为依托,加大对农业工程生产资料的投资力度;4)设立农业工程的行政管理部门,充分发挥行政管理部门的服务功能;5)在发展公司或公司加农户的科技农业园区的同时,发展以农户为基础进行集体化的组织和运行体系的研究,并在大学增设农业工程管理专业;6)大力发展以大学专科为基础的农业工程教育体系和进行农业工程教育学的研究.     

GABA and its agonists improved visual cortical function in senescent monkeys

Human cerebral cortical function degrades during old age. Much of this change may result from a degradation of intracortical inhibition during senescence. We used multibarreled microelectrodes to study the effects of electrophoretic application of gamma-aminobutyric acid (GABA), the GABA type a (GABAa) receptor agonist muscimol, and the GABAa receptor antagonist bicuculline, respectively, on the properties of individual V1 cells in old monkeys. Bicuculline exerted a much weaker effect on neuronal responses in old than in young animals, confirming a degradation of GABA-mediated inhibition. On the other hand, the administration of GABA and muscimol resulted in improved visual function. Many treated cells in area V1 of old animals displayed responses typical of young cells. The present results have important implications for the treatment of the sensory, motor, and cognitive declines that accompany old age.     

Genetic variation in captive population of chinese alligator, Alligator sinensis, revealed by random amplified polymorphic DNA (RAPD)

Chinese alligator (Alligator sinensis) is an endemic species in China. The likely extinction of it in the wild has been recognised. To prevent this species becoming extinct, the Anhui Research Centre of Chinese Alligator Reproduction (ARCCAR) was established in Xuanzhou, Anhui Province in 1979, where has been established the largest captive population of Chinese alligator (XZSP) in the world. Another farm (CXSP) was established by villagers in Changxin, Zhejiang Province. The results of an investigation of the two captive subpopulation structures by genetic analysis are presented in this paper. We examined the genetic variation in the two captive subpopulations using RAPDs. Thirty-one random primers were selected among 199 random primers screened. A total of 193 reproducible RAPD fragments were scored among 43 individuals, of which 21 (10.88%) were polymorphic. The genetic distances between 43 individuals ranged from 0 to 0.0376 with average of 0.0104±0.0055 S.E. The genetic similarity in CXSP (0.9948±0.0029 S.E.) was higher than that in XZSP (0.9894±0.0055 S.E.). The founder effect is a possible explanation for very low genetic variation in CXSP. Analysis of the RAPD data showed that the mean phenotypic band frequencies of each polymorphic loci was 0.6656±0.3730 S.E. The lowest phenotypic band frequency (0.0233) was found in four of those polymorphic loci. There was no genetic difference between the two subpopulations (D_ij=0.0009). According to the dendrogram and the distribution of polymorphic fragments in two subpopulations, CXSP originated genetically from XZSP. This paper summarises a preliminary research on genetic structure in populations of Chinese alligator. Although there is higher genetic similary (0.9896±0.0055 S.E.) in captive population of A. sinensis, we did not determine whether or not loss of genetic variation had occurred in relation to a wild control population. The data of malformed offspring will be collected carefully, and wild samples be added to set up a control population in future study.     

Incursion of bluetongue virus into the Okanagan Valley, British Columbia

Bluetongue virus was isolated from a sentinel herd in British Columbia. Virus isolation was by intravenous inoculation of embryonated chicken eggs and subculture in BHK-21 cells. The cytopathic agent was identified as bluetongue virus by electron microscopy and the immunoperoxidase test. The serotype was identified as serotype 11 by virus neutralization.     

Inhibition of formation of oxidative volatile components in fermented cucumbers by ascorbic acid and turmeric

Two naturally occurring antioxidants, ascorbic acid and turmeric, were effective in inhibiting formation of hexanal, (E)-2-penenal, (E)-2-hexenal, (E)-2-heptenal, and (E)-2-octenal when slurries of fermented cucumber tissue were exposed to oxygen. Added ascorbic acid prevented formation of most of these oxidative aldehydes at 175 ppm or greater. Turmeric, which is used commercially as a yellow coloring in cucumber pickle products, was found to almost completely prevent aldehyde formation at 40 ppm.     

鱼类主要内分泌激素和蛋白质代谢的关系

本文就鱼类主要的内分泌激素(T3、T4、GH、IGF-Ⅰ)对蛋白质代谢的调控以及饲料蛋白质质量和数量对鱼类内分泌激素分泌的调控进行概述。     

不同饲料蛋白质水平对吉富品系尼罗罗非鱼幼鱼生长和鱼体组成的影响

用3种不同蛋白含量(23.1%、37.6%和47.9%)的配合饲料投喂吉富品系尼罗罗非鱼幼鱼78d,结果显示,①随着饲料蛋白质含量从23.1%上升到47.9%,平均日增重从0.30g/d上升到0.74g/d,3组之间的日增重和体重有显著差异(P<0.05);饲料系数从1.53下降为0.98,3组之间的饲料系数有显著差异(P<0.05)。②不同的蛋白质水平对鱼体蛋白质和脂肪的含量有影响,各组之间差异显著(P<0.05),对灰分的影响差异不显著(P>0.05)。③蛋白含量为23.1%、37.6%和47.9%的配合饲料的成本分别为2.77元/kg、3.67元/kg、4.60元/kg。④初步认为蛋白含量为37.6%的配合饲料更适合吉富品系尼罗罗非鱼苗种培育的生产需要。     

有机酸的抗菌效应及其机制的研究进展

有机酸添加到日粮中能够抑制胃肠道细菌对可利用养分的竞争作用和减少可能的细菌代谢产物的毒性作用,有机酸还能够抑制饲料和胃肠道中潜在病原菌(大肠杆菌和沙门氏菌)的定植和繁殖,从而有益于动物的健康。文中就有机酸的抗菌作用作一综述,并分析其作用机制和微生物对有机酸的耐受性。