Effect of CO2 increase in atmosphere and UV-B intensification on Nostoc commune photosynthetic pigment and UV-B masking materials

Using Nostoc commune as experiment target,the effect of CO 2 with different concentrations in atmosphere and dosage of UV-B on photosynthetic pigment chlorophyll a (Chl a),carotenoids,phycoerythrin,phycocyanin,allophycocyanin and UV-B masking materials was studied.The results showed that high dosage of UV-B radiation inhibited the synthesis process of Chl a,phycoerythrin,phycocyanin and allophycocyanin,but promoted the synthesis of carotenoids,MAAs and scytonemin,thus the negative effect produced by UV-B radiation was reduced and the resistance of Nostoc commune against UV-B radiation was enhanced.     

离子交换分离混合氨基酸实验方法的改进

离子交换层析分离混合氨基酸是生物化学或生物制药工艺学实验课程中一个重要的制备性实验，为了更好地提高该实验对学生基本知识及综合能力的培养，作者改进了原有的实验教学设计，优化编写了新的实验教材，减少试剂消耗及实验耗时。氨基酸洗脱差异明显，洗脱原理更为多样，教学效果大幅度提高。     

Identification of mucondialdehyde as a novel stress metabolite

In a survey of antifungal stress compounds induced by cupric chloride we found that leaves ofChenopodium album exuded a highly fungitoxic metabolite mucondialdehyde (trans-2,trans-4-hexadienedial), which was associated with 13-oxo-9,11-tridecadienoic acids (cis-9,trans-11 andtrans-9,trans-11 isomers) presumably resulting from -scission of 13-hydroperoxy-octadecadi(tri)enoic acid. The biogenesis and role as a general defensive agent in plants are briefly discussed.     

The plasma level of some amino acids and physical and mental fatigue

Tryptophan is converted to 5-hydroxytryptamine (5-HT) in the brain and evidence is presented that an increase in the concentration of 5-HT can result in physical and mental fatigue during prolonged exercise. The entry of tryptophan in the brain is influenced by the plasma level of free tryptophan (that not bound to albumin) and, from competition for entry into brain, by the plasma level of branched chain amino acids. Hence, oral administration of branched chain amino acids could, theoretically, prevent the increase in 5-HT level during exercise and therefore delay physical and mental fatigue. Evidence in support of this hypothesis is presented.     

Possible involvement of the phloem sealing system in the acceptance of a plant as host by an aphid

Possible reasons for the rejection of some lines ofTriticum monococcum (Tm44 and Tm46) by the aphidSitobion avenae were explored. In allT. monococcum lines studied, whether unfavourable (non-host/resistant plant) or favourable (host/susceptible plant), the concentrations of hydroxamic acids, a family of aphid-resistance factors in cereals, were significantly lower than the levels in the favourable host-plantTriticum aestivum cv. Therefore, hydroxamic acids did not account for the host/non-host patterns observed. Phloem sap was collected by stylectomy from young seedlings of favourable and unfavourable plants. In non-aphid-resistant genotypes, the success in stylectomy, the proportion of amputated stylets resulting in long (>1 min) exudations, the average duration of exudation, and the final volume of sap exuded, were higher than in the aphid-resistant genotypes. It is concluded that aphid interference with the phloem sealing system of the plant is a likely mechanism of rejection ofT. monococcum lines Tm44 and Tm46 as hosts byS. avenae.     

β－环糊精固载相薄层层析法直接拆分氨基酸D，L－对映体

以环氧氯丙烷作为多功能官能团交联剂，经化学合成反应，将β－环糊精固载在活性轻质二氧化硅表面上，以此为固定相制备成层析薄板，直接用于拆分氨基酸的Ｄ，Ｌ－对映异构体．实验结果表明：该层析薄板在脱氧胆酸或尿素的协同作用下，可用于拆分亲脂性基因与手性碳直接相连的氨基酸Ｄ，Ｌ－对映体．研究了在展开剂中不同浓度的脱氧胆酸和尿素两种立体选择助剂对这３种氨基酸的Ｄ，Ｌ－对映异构体的分离效果的影响，并对其机理进行了初步讨论．     

12－钼钨硅杂多酸在丙酸异戊酯合成过程中的催化作用

本文首次报道了用１２－钼钨硅杂多酸催化合成丙酸异成酯，得出了最佳酸醇（ｍｏｌ）比为：１．０５～１．０８：１，反应时间为１．５ｈ，催化剂用量为５～６‰，催化剂的选择性为１００％，且连续使用３０次，活性稍有下降，还考察了带水剂对酯化反应的影响．     

用溶剂萃取法精制粗环烷酸

用溶剂萃取法在较低温度下精制粗环烷酸．对酸值１４０ｍｇＫＯＨ／ｇ及含油３０．１％的辽河粗环烷酸进行精制后，酸值可达１９０ｍｇＫＯＨ／ｇ以上，酸回收率及纯度均可达到９０％以上，精制过程中无三废排放，这是精环烷酸脱油精制的一种经济、有效的方法．     

环境因子对高盒形藻细胞内蛋白质和氨基酸含量的影响

在实验室模拟条件下研究了光强、温度和氮磷比等环境因子对高盒形藻细胞内蛋白质（Ｐｒ）和氨基酸（ＡＡ）的影响．结果表明：该藻细胞内的Ｐｒ和ＡＡ含量在３０６５～１００８５ｌｘ光强内随光强的增强而降低；在２７℃左右达到最大；当氮磷比为１６时有最高值，光强、温度及光照的亮暗交替变化不影响该藻细胞内ＡＡ与Ｐｒ的含量百分比，但介质Ｎ／Ｐ比值与ＡＡ／Ｐｒ百分比呈线性相关。     

缺铁失绿的苹果幼苗叶片中核酸和蛋白质代谢的变化

缺铁失绿苹果幼苗叶片中DNA、RNA含量明显下降。试验证明,这是合成下降和分解加快两方面的总效应。失绿叶片的25S、23S和16S rRNA下降也较大。另外,小分子量RNA影响也较大。叶片可溶性蛋白质含量也明显下降,试验表明,这也是合成下降和分解加快两方面的总结果。叶片游离氨基酸的含量增加,氮基酸组分也发生的深刻的变化,其中精氨酸明显升高。