The effect of some Frescon analogs on the aquatic snail,Lymnaea stagnalis: II. Correlation of neurotoxicity to Molluscicidal effectiveness

Although the molluscicide Frescon is a strong neurotoxin to the Lymnaea stagnalis central nervous system in vitro, it is probable that the exposure of the whole animal to this molluscicide fails to result in central nervous system abnormalities: Frescon does not appear to reach the brain in sufficient quantity to disrupt its normal activity. However, only those Frescon analogs found to be neurotoxic were molluscicidal, suggesting some related mode, if not site, of action. Frescon and its analogs may act by affecting excitable tissues other than the nervous system (e.g., the snail musculature) by altering certain functional and/or structural membrane properties.     

Effects of chlordimeform on mitochondria from eggs of Spodoptera littoralis

Mitochondria were isolated from eggs of Spodoptera littoralis. With succinate (+pyruvate) as substrate, respiratory control ratios between 1.70 and 2.54 were obtained. Uncouplers and the energy transfer inhibitor oligomycin influenced these mitochondria in the well-known manner. The uncoupling activity of chlordimeform in vitro was very weak and decreased with increasing age of the eggs. Electron transport in mitochondria from chlordimeform-treated eggs was not uncoupled. Therefore, it is concluded that the ovicidal effect of this pesticide is not due to its uncoupling effect.     

The effect of phosphine on the absorption and circular dichroic spectra of cytochrome c and cytochrome oxidase

The interaction of phosphine with purified cytochrome c and cytochrome oxidase was studied by absorption and circular dichroic spectrometry. Treatment of cytochrome oxidase with phosphine yielded absorption spectra in both the visible and Soret region that were similar to that produced by dithionite. Striking changes in the circular dichroic spectra were also recorded, sugesting that a valence change of the heme iron was accompanied by a conformation change of the prosthetic group.Phosphine treatment of cytochrome c also yielded spectra similar to those produced by reduction with dithionite suggesting a valence change of the heme iron. However, both the time necessary for complete reduction and the concentration of phosphine necessary for this effect suggest that, in comparison with cytochrome oxidase, cytochrome c was relatively insensitive. Reduction of cytochrome oxidase by phosphine had only a very minor effect on the intrinsic dichroic spectrum suggesting little effect on the polypeptide chains.The persistence of a component after reduction by phosphine and the subsequent reduction of this component by dithionite suggests that phosphine primarily reduced only one comonent of the cytochrome aa₃ complex. The failure of EDTA and fluoride, which are known ligands of cytochrome a₃ to affect the reduction of cytochrome aa₃ by phosphine, as well as the occurrence of a 436-nm isosbestic point of the ferric-ferrous absorption spectra suggests that phosphine reduced primarily cytochrome a. However, it is argued that a slow reduction of cytochrome a₃ cannot be ruled out.     

新疆退牧还草工程建设与管理的探讨

草地是发展畜牧业的重要基础,退牧还草工程是恢复、更新天然草地和保护生态环境的重要手段。本文就新疆实施退牧还草工程中所出现的一些问题进行了探讨。     

Prediction of breeding values for osseous fragments in fetlock and hock joints, deforming arthropathy in hock joints, and pathologic changes in the navicular bones of Hanoverian Warmblood horses

The results of a standardised radiological examination of 5928 Hanoverian Warmblood horses selected for sale at auction were used to predict relative breeding values (RBV) in the 23,662 horses included in the last four generations of the probands' pedigrees. The distribution of the RBV was investigated in the whole four-generation pedigree, in the probands and in those stallions that contributed at least three offspring to the probands. The RBV of the probands' sires were further compared with the officially published performance-based relative breeding values, i.e., total indices dressage (TID) and jumping (TIJ). The sires' level of dressage indices was considerably higher (mean TID=110) than of the jumping indices (mean TIJ=98). Total indices radiographic findings (TIR) were calculated for the sires with varying weighting given to the individual RBV. In each case, this resulted in a mean TIR of 99. Finally, total indices were derived from TIR and TID and/or TIJ in order to develop different selection schemes for all-purpose breeding and for breeding focused on dressage and show jumping. All breeding values under consideration increased by between 1% and 19% when radiographic findings were weighted with between 30% and 60% complementary to the corresponding performance parameters, and when only sires were selected with above average total indices. At the same time, the prevalences of the radiographic findings investigated here were lowered by up to 10% each. When only one radiographic finding was considered at a time, the maximum attainable response to selection was a 16-23% increase in the relative breeding values and a relative decrease in prevalences of radiographic findings of between 31% and 52%. The results of this study indicate that it is possible in horse breeding to consider simultaneously health and performance traits. Medical data should be included in the prediction of breeding values in order to improve the radiological status of today's riding horses.     

Genetic analyses of resistance of the wheat differential cultivars Carstens V and Spaldings Prolific to two races of Puccinia striiformis

Genetic analysis of resistance of wheat seedlings to two races of Puccinia striiformis was conducted on F₁, F₂ and F₃ generations from crosses Carstens V (CV) × Lee, Spaldings Prolific (SPA) × Lee and CV × SPA. F₂ generations from crosses of CV and SPA with Strubes Dickkopf (SD) were also studied. The plants were classified into six resistance classes and analysed by factorial correspondence analysis and nonhierarchical classification. The two P. striiformis isolates tested were a French isolate of race 43E138 and a Lebanese isolate of race 2E16, selected for the differences in their virulence spectra for the common differential cultivars Strubes Dickkopf and Nord Desprez. Resistance of CV and SPA was recessive and dominant to races 43E138 and 2E16, respectively. CV possessed three or four resistance genes, one of them being expressed with both races. Two genes of CV had a cumulative effect for resistance to 43E138 and two or three gave dominant resistance to 2E16. SPA had three resistance genes, all of which gave resistance to 2E16 and two of which also gave resistance to 43E138. SPA had one gene in common with CV for resistance to both races. Furthermore, the gene for resistance to race 2E16 in CV and SPA was allelic with a gene in SD, and was probably Yr25 .     

甘肃陇南小麦不同品种类型抗条锈性变化特点分析

 1973~2002年的30年间,在我国小麦条锈病常发易变区的陇南,对小麦主要生产品种的抗条锈性变化动态进行了系统的观察,选择具垂直抗性、慢条锈性、高温抗性和持久抗性等不同类型的7个品种的观测数据进行了分析,认为里勃留拉和N.斯特拉姆潘列长期保持了稳定的抗锈性。里勃留拉的抗性可能由多对微效基因控制,N.斯特拉姆潘列的抗性可能由主效基因控制,兰天12号所具有的慢锈性和兰天1号的高温抗性以及抗条锈基因的合理布局对延长品种抗性也有一定作用。     

粳稻品种抗稻瘟病性与其生物学性状的相关关系研究

对３４２份粳稻材料进行抗稻瘟病性（抗叶瘟、穗颈瘟）与其生物学性状（株高、穗长、每穗粒数、分蘖率、单株有效分蘖数、空秕率、着粒密度，以及成熟期等）相关关系研究，结果不同品种（系）间存在着一定差异。抗叶瘟性与株高、穗长、每穗粒数、单株有效分蘖数、着粒密度呈显著正相关，相关系数依次为：０．４０９、０．４９１、０．４２６、０．６５７、０．４７１；与空秕率呈显著负相关，相关系数为－０．５９１。抗穗颈瘟性与株高、每穗粒数、单株有效分蘖数呈显著正相关，相关系数分别为：０．７１７、０．４６２、０．３６２；与空秕率、分蘖率、着粒密度呈显著负相关，相关系数依次为：－０．３４３、－０．３３２、－０．４７６。试验表明，株高、单株有效分蘖率、每穗粒数、空秕率等性状，可做为主要标记，在粳稻品种（系）抗稻瘟病性选鉴上应用     

云南省稻瘟病,小麦锈病预测专家系统

基于稻瘟病、小麦锈病预测领域专家知识,以及借助模式识别势函数法实现的自学习、自提取的知识,采用正向和反向精确推理控制策略,首次建立云南省水稻穗瘟病、小麦条锈病预测专家系统,1994～1995年预测结果与实际情况基本一致。系统创造性地采用全屏幕编辑树图的知识输入法和森林表示技术对知识库进行管理,便于知识库的扩充和维护。推理结果、推理路径及知识查询以彩色图形方式显示,对于学习领域专家的实践经验具有独特优点。     

猕猴桃新品种‘中猕1号’

 ‘中猕1号’是从河南伏牛山区野生资源中选出的猕猴桃新品种，结果早，丰产，抗逆性强，果实大，品质优，果肉绿色，果心小，种子少，味甜，有浓郁清香味。