酸碱度对温和噬菌体存活与吸附效率的影响

实验测定了ｐＨ对Ｂａｃｉｌｕｓｔｈｕｒｉｎｇｉｅｎｓｉｓｖａｒ．ｅｎｔｏｍｏｃｉｄｕｓ温和噬菌体ＴＰ３存活与吸附效率的影响作用。结果表明：在不同ｐＨ的介质中,ＴＰ３存活的能力相差很大;酸性介质及高碱性介质对ＴＰ３都有不同程度的瞬间灭活作用;ＴＰ３存活的最适ｐＨ为７．７,且适宜其存活的ｐＨ范围很窄;ｐＨ不同,ＴＰ３吸附到苏云金芽孢杆菌表面上的效率也不同,在ｐＨ≥９范围内,ｐＨ升高,吸附效率降低。     

低频超声波对大豆胰蛋白酶抑制素的处理效果

采用２０ｋＨｚ的低频超声波对大豆胰蛋白酶抑制素（ＳＴＩ）进行了处理。结果表明,超声波对经纯化了的鲍曼－贝尔克抑制素（ＢＢＩ）几乎不起钝化作用,对生豆奶中天然存在的ＳＴＩ的钝化效果要比对从大豆中提取纯化的ＳＴＩ好得多,说明纯化了的ＳＴＩ似对超声处理较稳定;豆奶中大分子蛋白组分１１Ｓ和７Ｓ的存在有助地ＳＴＩ的纯化;低频超声波对生豆奶中的ＢＢＩ似乎有轻微的激活作用;在生豆奶中添加半胱氨酸、亚硫酸钠的胃液     

乳酸对肌酸激酶活性抑制作用的研究

应用酶活测定的方法分析了肌酸激酶在不同浓度乳酸中的活性变化．实验结果说明在失活过程中没有蛋白质的聚沉；肌酸激酶的失活遵循一级反应的一相过程；失活与乳酸浓度和作用时间呈正相关．通过对比实验结果显示，乳酸是通过其解离状态的H^ 改变了机体PH值而影响肌酸激酶活性的，并且就乳酸对肌酸激酶影响及其意义进行探讨．     

五种预氧化工艺处理污染原水的消毒性能比较

观察了水中腐殖酸和乳糖蛋白胨培养液的含量变化对高锰酸钾、氯、氯胺单独处理工艺及高锰酸钾与氯或氯胺联用工艺消毒效果的影响．结果表明，有机物浓度越高，高锰酸钾与氯或氯胺联用工艺与单独氯或氯胺工艺消毒效能相比所占优势越明显，尤其是当水中含有大量有机氮化合物时，采取高锰酸钾与氯或氯胺联用能更有效提高预处理时消毒效能．对有机污染严重的水源水进行预处理时，高锰酸钾与氯或氯胺联用预氧化能够减少有机物对消毒效果的影响，发挥预处理工艺对致病微生物的多级屏障作用，保障供水安全。     

Conotoxins of the O-superfamily affecting voltage-gated sodium channels

The venoms of predatory cone snails harbor a rich repertoire of peptide toxins that are valuable research tools, but recently have also proven to be useful drugs. Among the conotoxins with several disulfide bridges, the O-superfamily toxins are characterized by a conserved cysteine knot pattern: C-C-CC-C-C. While ω-conotoxins and κ-conotoxins block Ca²⁺ and K⁺ channels, respectively, the closely related δ- and μO-conotoxins affect voltage-gated Na⁺ channels (Na_v channels). δ-conotoxins mainly remove the fast inactivation of Na_v channels and, thus, functionally resemble long-chain scorpion α-toxins. μO-conotoxins are functionally similar to μ-conotoxins, since they inhibit the ion flow through Na_v channels. Recent results from functional and structural assays have gained insight into the underlying molecular mechanisms. Both types of toxins are voltage-sensor toxins interfering with the voltage-sensor elements of Na_v channels. Received 27 December 2006; received after revision 30 January 2007; accepted 19 February 2007     

Gene inactivation triggered by recognition between DNA repeats

This chapter focuses on phenomena of gene inactivation resulting from the presence of repeated gene copies within the genome of plants and fungi, and on their possible relationships to homologous DNA-DNA interactions. Emphasis is given to two related premeiotic processes: Methylation Induced Premeiotically (MIP) and Repeat-Induced Point mutation (RIP) which take place in the fungiAscobolus immersus andNeurospora crassa, respectively. The relationships between these processes and genetic recombination are discussed.     

中华猕猴桃蛋白酶热失活动力学

改进了酶的提纯方法获得聚焦电泳为单一区带酶制剂。酶热失活以 HbCO 为底物时为一级反应,动力学方法表明 HbCO 对酶的热失活有保护作用,68.90℃时k_(+0)/k′_(+3)比值24,“HbCO”络合物活化能 535kJ/mol,焓 531 kJ/mol,自由能 116kJ/mol,熵1 212kJ/mol,生成自由能和生成热分别为20和209kJ/mol,这些参数说明 HbCO对酶热失活保护作用以及对酶构象影响可能与二者的多键结合和HbCO 水化作用有关。本文中还得到CBZ-Lys-ONp 为底物的热力学参数,观察到 DTT 对酶热失活保护是很小的。     

催化动力学荧光法同时测定SCN~－和I~－

利用Ｉ￣－、ＳＣＮ￣－都对Ｃｅ（Ⅳ）与Ａｓ（Ⅲ）的氧化还原反应具有催化作用的特点，动力学荧光法测定Ｉ￣－、ＳＣＮ￣－含量。又利用ＳＣＮ￣－时上述氧化还原反应的催化活性在一定条件下会失去的特点，选择性测定Ｉ￣－，进尔计算出ＳＣＮ￣－的含量，测定Ｉ￣－、ＳＣＮ￣－的线性范围分别为６．０×１０￣（－４）～６．０×１０￣（－３）、６．９×１０￣（－２）～１．４ｍｇ／Ｌ．水样回收率分别为８５％～１１０％和８８％～１１７％。     

Calmodulin modulation of ion channels and receptors

Ion channels and receptors are the structural basis for neural signaling and transmission. Recently, the function of ion channels and receptors has been demonstrated to be modulated by many intracellular and extracellular chemicals and signaling molecules. Increasing evidence indicates that the complexity and plasticity of the function of central nervous system is determined by the modulation of ion channels and receptors. Among various mechanisms, Ca 2+ signaling pathways play important roles in neuronal activity and some pathological changes. Ca 2+ influx through ion channels and receptors can modulate its further influx in a feedback way or modulate other ion channels and receptors. The common feature of the modulation is that Ca 2+ /calmodulin (CaM) is the universal mediator. CaM maintains the coordination among ion channels/receptors and intracellular Ca 2+ homeostasis by feedback modulation of ion channels/receptors activity. This review focuses on the modulating processes of ion channels and receptors mediated by CaM, and further elucidates the mechanisms of Ca 2+ signaling.