Eggplant tissue homogenate-based bioselective membrane electrode for determination of catechol.

A novel eggplant tissue homogenate-based membrane electrode with high selective response to catechol (5 x 10(-6)-2.5 x 10(-5) M concentration) has been constructed by immobilizing tissue of eggplant (Solanum melangena L.) at dissolved oxygen probe. In order to optimize the stability of the electrode, general immobilization techniques are used to secure the eggplant tissue section physically in a gelatin-glutaraldehyde cross-linking matrix. The electrode response was maximum when 50 mM phosphate buffer was used at pH 7.0 and 35 degrees C. The sensor is stable for more than 3 months.     

茶蚕颗粒体病毒田间防治技术研究

1980年10月在安徽省舒城县采集茶蚕虫尸,分离出一株茶蚕颗粒体病毒。小区试验及大面积防治示范表明:茶蚕颗粒体病毒防治茶蚕,致病死亡速度与气温密切相关;防效不受夏季较高气温影响,而受秋季较低气温影响;每亩剂量为100—200mg,气温低于20℃以200mg为宜;对各代虫体均有较好防治效果,为75.5—97.5％;防治适期以卵盛孵期至2龄前幼虫为宜。气温低于20℃时,病毒与低剂量杀虫双混用有明显的增效作用,增效18.8％,缩短死亡期6天,病毒对天敌安全,后效作用明显,1—3年内,感病死亡率为40—56.4％。     

Cooperativity,absolute interaction,and algebraic optimization

We consider a measure of cooperativity based on the minimal interaction required to generate an observed titration behavior. We describe the corresponding algebraic optimization problem and show how it can be solved using the nonlinear algebra tool SCIP. Moreover, we compute the minimal interactions and minimal molecules for several binding polynomials that describe the oxygen binding of various hemoglobins under different conditions. We compare their minimal interaction with the maximal slope of the Hill plot, and discuss similarities and discrepancies with a view towards the shapes of the binding curves.

     

Ambient temperature effects on brain and spinal cord acetylcholinesterase activity of two poikilotherms

The changes in AChE activity and protein content following cold or heat exposure and heat death were determined in the brain and spinal cord of both Rana ridibunda and Chalcides ocellatus. Cold exposure (10 degrees C) caused a decrease in the enzyme activity and protein content of both animals. Exposure to heat (36-40 degrees C) increased markedly the AChE activity and the amount of protein in the two experimental animals. Heat death was found to be associated with a prominent decrease in enzyme activity and the protein level of the brain and spinal cord of the two poikilotherms.