植物生物技术:苏云金杆菌抗虫基因的研究和它对未来树木遗传工程的影响

许多不同的技术可以促进农业生产力的持续增长，生物技术是其中最重要和最有前途的方法。因为生物技术不仅可以增加生产力。而且在环境和自然资源的保护中起重要作用，应用生物技术可以生产高产、优质、高抗性和无病植物，同时也可以提高育种效率和促进食品的工业化生产。苏云金杆菌抗虫基因是目前生物技术领域中应用最广泛的例子之一。由此而产生的抗虫植物正在广泛应用于世界各地的商业化生产。本文综述了苏云金杆菌抗虫基因的研究进展和它在未来林木遗传工程中的应用。表4参68。     

Horses,saddles and riders: Applying the science

An enthusiastic crowd of 400 people gathered at Anglia Ruskin University in Cambridge, UK on 29 November 2014 for the second International Saddle Research Trust Conference on the theme of Horses, Saddles and Riders: Applying the Science. The conference was organised under the auspices of the Saddle Research Trust (SRT) which is a charitable organisation based in the UK established with the intention of stimulating and supporting research into the influence of saddles on the welfare, performance and safety of horses and riders using objective scientific methods. The SRT aims to provide a coordinated, focused approach to research in these areas, to facilitate publication of the findings in scientific journals and dissemination of the results to the equestrian world. This approach allows the SRT to act as a link between research, education and the industry. The trust supports research into all aspects of the interaction between the horse, saddle and rider. Areas of specific recent interest include studying welfare, performance and safety issues related to the use of a saddle, the role of the saddle in equine and human back problems, characterising behavioural issues of horses associated with saddle‐related discomfort, assessing the effects of saddle design on rider performance and health and designing saddles for disabled riders. Further information about the SRT is available on the website www.saddleresearchtrust.com . Sponsors of the conference were World Horse Welfare, a practical and forward‐thinking charity that believes in using scientific evidence to help guide its work, Amerigo saddlers, a company that advocates research as a basis for improving product design, the British Equestrian Federation (BEF) and Horse and Hound.     

The effect of vitamin E on the serum complement activity of the rainbow trout, Oncorhynchus mykiss (Walbaum)

Rainbow trout were fed three experimental diets with varying levels of vitamin E (α‐tocopherol) supplementation (0, 100 and 1000 mg kg^?1 diet), and the effects of feeding these diets on serum spontaneous haemolytic activity and classical complement activity were investigated. Hepatic α‐tocopherol levels reflected the dietary intake of the vitamin. Fish fed the diet deficient in vitamin E showed reduced growth and increased mortality. Their hepatosomatic index and erythrocyte fragility was significantly higher than both the supplemented groups and haematocrit, and complement activity were all significantly lower. There appeared to be some enhancement of serum complement activity correlated with increased dietary supplementation with vitamin E but the benefits of supplementation at levels above those currently recommended were not established.     

Effects of oxygen supersaturation and temperature on juvenile greenlip, Haliotis laevigata Donovan, and blacklip, Haliotis rubra Leach, abalone

Growth and survival of juvenile greenlip (39.03 (SD 3.80) mm (n=524)) and blacklip (31.92 (SD 4.19) mm (n=531) abalone were investigated at high dissolved oxygen levels (95–120% saturation) between 17 and 19°C. Abalone were fed the same artificial diet and each species was contained in groups of approximately 30 individuals within triplicate tanks for each of six treatments and were exposed to flow through water adjusted to give experimental conditions for up to 75 days. Blacklip abalone held at 16.9°C and 97% oxygen saturation grew in shell length significantly faster than all other treatments of blacklip abalone held at 19°C, and significantly faster than blacklip abalone maintained at 111% oxygen saturation and 17.5°C. Both temperature and oxygen saturation significantly affected the survival of this species. Blacklip abalone held at 19°C had significantly lower survival for both 96% oxygen saturation and 120% oxygen saturation, compared with blacklip abalone maintained at either 110% oxygen saturation and 19°C, or for any 17°C treatment. No significant differences were noted for greenlip abalone within the range tested in terms of growth rate, food consumption rate or survival, indicating that greenlip abalone tolerated these conditions better than did blacklip abalone.     

Nitrogen excretion and absorption efficiencies of white steenbras, Lithognathus lithognathus CuvieSparidae, under experimental culture conditions

The various components of the nitrogen budget of white steenbras,Lithognathus lithognathus Cuvier (Sparidae), were determined under experimental culture conditions. A simple closed system respirometer was used where experiments were conducted to investigate faecal prodution, nitrogen excretion rates and absorption efficiencies at 16C and 20C. Faecal loss, as a percentage of the ingested nitrogen, amounted to 3.59%. Gross, carbon and nitrogen absorption efficiencies ranged from 8 6 to 9 8 % and were not significantly affected by fish size, ration size or temperature (P < 0.05). Net protein utilization (NPU) and the biological value (BV) ranged from 78 to95%. Ammonia and urea constituted 77.93 and 10.07%, respectively, of the total exogenous nitrogen excretion, the balance being made up of other dissolved organic nitrogen (DON). Endogenous ammonia excretion rates were significantly greater in small fish compared to large fish (P < 0.05). Total non-faecal losses as a percentage of the ingested ration amounted to 21.86%. Fish size and ration size increased nitrogen excretion, but temperature had no effect. Maintenance rations were 7.55 mg g-¹ dry weight day-¹ (0.76%dry body weight) and 5.99 mgg-¹ (0.60% dry body weight) for small and large fish, respectively. The high absorption efficiencies and high nitrogen indicated that white steenbras utilize the commercial trout pellet diet very efficiently.     

Laboratory testing in pet avian medicine.

The importance of employing laboratory diagnostics in the examination of avian patients cannot be overemphasized. The physical examination alone is grossly insufficient. Many avian illnesses do not display external signs, and laboratory work is imperative in detecting them. Only after the assessment of various laboratory parameters can an examination be considered complete.