温度和规格对波纹巴非蛤耗氧率和排氨率的影响

本研究以波纹巴非蛤为实验材料,比较了温度和规格对其耗氧率和排氨率的影响。实验温度设为15、20、25和30℃,设立了大（A）和小（B）两种规格,其壳长分别为4.35 ± 0.19 cm 和3.53 ± 0.15 cm。结果表明温度对耗氧率和排氨率存在显著影响（P < 0.05）。规格对耗氧率存在显著影响（P > 0.05）,而对排氨率影响不显著（P > 0.05）。在温度15 - 30℃之间,波纹巴非蛤的耗氧率随温度升高而增大。在15和20℃条件下,B组的耗氧率显著大于A组（P < 0.05）;在25和30℃条件下,B组的耗氧率大于A组,但差异不显著（P > 0.05）。在温度15 - 30℃之间,波纹巴非蛤的排氨率随温度升高而增大。在各温度条件下,两组排氨率没有显著差异（P > 0.05）。     

多杀菌素和荧光桃红B对橘小实蝇的毒力测定

为进一步筛选适合田间施用蛋白诱剂条件下的实蝇杀虫剂种类和用量,室内测定了多杀菌素和荧光桃红B分别与阮酵母水解蛋白组配后对橘小实蝇自由取食的胃毒毒性.结果表明,多杀菌素和荧光桃红B均适合与水解蛋白组配防治橘小实蝇.多杀菌素和荧光桃红B对橘小实蝇雌、雄成虫在5h内的致死中浓度分别为12.7570、13.9535和779.9378、826.6259mg/kg,16和100mg/kg多杀菌素对橘小实蝇雌、雄成虫的致死中时间分别为4.1904、4.9730h和2.4877、2.6755h,630和1000mg/kg荧光桃红B对橘小实蝇雌、雄成虫的致死中时间分别为5.3507、4.9462h和4.7650、4.5715h.     

Heat stress in dairy cattle and other livestock under southern African conditions. III. Monthly temperature-humidity index mean values and their significance in the performance of dairy cattle

Temperature-humidity index (THI) values applicable to South Africa and Namibia have been established during this investigation for each month of the year by means of computerized modelling and mapping techniques. The data indicate that each year heat stress risk areas (HSRA's) expand from August to January and retract from February to July. The THI values classified according to the Livestock Weather Safety Index (LWSI) for lactating dairy cattle (LDC), suggest that, especially during November to March there is the risk of moderate to advanced heat stress in most South African dairy cows. This has important implications for their general health, udder health, production and reproduction. Careful planning of facilities and highly adaptable herd management are required to protect dairy cattle from heat stress.     

Radiologic anatomy of the normal appendicular skeleton of the lion (Panthera leo). Part 1: thoracic limb.

Thoracic limb specimens from 12 euthanized free-ranging lions (Panthera leo, 16-170 mo old) underwent radiographic evaluation. The radiographic anatomy was described but excluded any areas of the bones with possible bone pathology. Comparisons between adult and juvenile lions were made and physes described. Differences or similarities (or both) to cheetahs (Acinonyx jubatus) and domestic cats and dogs were also noted. No dissections were made to corroborate the anatomic observations, but comparisons were made to macerated museum specimens. On the basis of evaluation, the scapula has a prominent acromion, hamate, and suprahamate processes, as well as prominent nutrient foramina. The humerus is similar to that of domestic cats. The humeral and ulnar nutrient foramina originate more medially than that in domestic cats. A supracondylar foramen may sometimes be observed radiologically, although one was present on all the macerated specimens in this study. Its radiologic visibility depends on the angle of incidence of the primary beam. The lateral "anconeal tubercle" of the olecranon (situated between the processus anconeus and tuber olecrani) is usually more prominent than the medial one and tends to be hook shaped, pointing cranially. There are no sesamoids in the region of the elbow. The first digit is large with two palmar metacarpophalangeal sesamoids and a prominent sesamoid in the tendon of the M. abductoris digiti I longus, all indications of a high degree of functionality. All physes close before 66 mo of age.     

Workshops propose national programme for veterinary helminthology for South Africa

A workshop was held at Onderstepoort on 2-3 July 1999 to set priorities in veterinary helminthology for South Africa. Representatives from 19 organisations attended. The workshop achieved 2 of its 3 aims, namely to identify the priority areas within the field and to set specific objectives to be achieved in addressing these needs. Seven strategies were proposed, namely, motivation, education, therapeutic, worm resistance, animal tolerance, biological control and diagnostic strategies. A follow-up session took place on 8 September 1999 and at this workshop and in subsequent meetings, preliminary action plans were developed for these strategies. It was felt that the proposed activities delineated by this process should form the basis for a National Programme for Veterinary Helminthology and a national forum is to be convened to encourage all stakeholders to consider, discuss and adopt these activities. The forum is scheduled to take place in April 2000.     

Neopolystoma liewi sp. n. (Monogenea: Polystomatidae) from the eye of the Malayan box turtle (Cuora amboinensis)

Neopolystoma liewi sp. n. is described from the conjunctival cavity of the Malayan box turtle Cuora amboinensis (Daudin, 1802), in Peninsular Malaysia. This is the first record of Neopolystoma in Malaysia and the fourth polystomatid species described from C. amboinensis. Of the 27 Malayan box turtles examined, 8 were found to be infected. A maximum of 2 parasites per eye and 4 individuals per host was recorded. N. liewi sp. n. differs from all other members of the genus by possessing few and short genital spines and small marginal hooks. The oncomiracidium has 64 ciliated cells arranged symmetrically about the sagittal axis.     

Cell recognition during neuronal development

Insect embryos, with their relatively simple nervous systems, provide a model system with which to study the cellular and molecular mechanisms underlying cell recognition during neuronal development. Such an approach can take advantage of the accessible cells of the grasshopper embryo and the accessible genes of Drosophila. The growth cones of identified neurons express selective affinities for specific axonal surfaces; such specificities give rise to the stereotyped patterns of selective fasciculation common to both species. These and other results suggest that early in development cell lineage and cell interactions lead to the differential expression of cell recognition molecules on the surfaces of small subsets of embryonic neurons whose axons selectively fasciculate with one another. Monoclonal antibodies reveal surface molecules in the Drosophila embryo whose expression correlates with this prediction. It should now be possible to isolate the genes encoding these potential cell recognition molecules and to test their function through the use of molecular genetic approaches in Drosophila.