外电场影响酶活性机制初探

用电子－构象相互作用理论研究了外电场影响酶活性的分子机理，并讨论了相关的问题，结构表明强外场有利于激发酶的活性。     

Short cerebral ischemia and subsequent reperfusion and treatment with stobadine

Lipid peroxidation and activities of antioxidative enzymes were studied in the brain cortex after short (15 min) cerebral ischemia and reperfusion (10 min) in rats. Conjugated dienes (CD) and thiobarbituric acid-reactive substances (TBARS) were significantly elevated in the group of rats with ischemia followed by reperfusion in comparison to the ischemic animals. Superoxide dismutase (SOD) activity significantly increased in the group of animals with ischemia and reperfusion. No significant changes in the activities of glutathione peroxidase (GP) were observed. Stobadine administered before ischemia or before reperfusion decreased the level of TBARS. Stobadine probably prevents malondialdehyde (MDA) formation from hydroperoxide or might elevate the activity of aldehyde dehydrogenase. In contradiction to the findings after long-lasting (4 h) ischemia and subsequent reperfusion¹, no decrease in the concentration of CD or in the activity of SOD or GP was found.     

Theearly andlate processing of lysosomal enzymes: Proteolysis and compartmentation

Lysosomal enzymes are subjected to a number of modifications including carbohydrate restructuring and proteolytic maturation. Some of these reactions support lysosomal targeting, others are necessary for activation or keeping the enzyme inactive before being segregated, while still others may be adventitious. The non-segregated fraction of the enzyme is secreted and can be isolated from the medium. It is considered that the secreted lysosomal enzymes fulfill certain physiological and pathophysiological roles. By comparing the secreted and the intracellular enzymes it is possible to distinguish between the reactions that occur before and after the segregation. In this review the reactions that may influence the segregation are referred to as the early processing and those characteristic for the enzymes isolated from lysosomal compartments as the late processing. The early processing is characterized mainly by modifications of carbohydrate side chains. In the late processing, proteolytic fragmentation represents the most conspicuous changes. The review focuses on the compartmentation of the reactions and the proteolytic fragmentation of lysosomal enzyme precursors. While a plethora of proteolytic reactions are involved, our knowledge of the proteinases responsible for the particular maturation reactions remains very limited. The review points also to work with cells from patients affected with lysosomal storage disorders, which contributed to our understanding of the lysosomal apparatus.     

花生“汕油523”在盐胁迫下应激反应的初步研究

分别模拟盐胁迫的离子胁迫、渗透胁迫处理花生 (Arachishypogaea L.cv.Shanyou52 3) ,研究了离子胁迫、渗透胁迫对花生抗氧化酶的影响 .结果表明 :等渗的 Na Cl、 KCl(50　mmol/ L、 1 0 0　mmol/ L )和聚乙二醇 (PEG　6　0 0 0 ,1 6%、 2 6% )诱导花生叶片超氧化物歧化酶 (SOD)活力显著升高 ;低浓度 (50　mmol/ L) Na Cl胁迫可以诱导花生叶片过氧化物酶 (POD)活力升高 ;花生叶片过氧化氢酶 (CAT)活力在 PEG胁迫处理下呈显著下降趋势 ,而在 Na Cl和 KCl处理下变化不大 ,表明盐胁迫时引起花生叶片 CAT活力的下降的原因可能是渗透胁迫 .     

DBP对秋茄幼苗光合作用和抗氧化酶活性的影响

在实验室条件下,分别以0、0.02、0.20、2.00、5.00、10.00 mg/L 6个质量浓度的邻苯二甲酸二丁酯(DBP)培育红树植物秋茄(Kandelia candel(L.)Druce)幼苗.6个月后对秋茄幼苗的叶绿素含量和抗氧化酶(包括丙二醛(MDA)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD))活性进行分析.研究结果表明:DBP对秋茄幼苗叶绿素含量没有产生不利的影响,相反具有促进作用;随DBP质量浓度的提高,秋茄幼苗叶片MDA含量相应增加,CAT、POD和SOD活性整体呈先上升后下降的趋势.说明,秋茄幼苗能在所设质量浓度的DBP范围内正常生长,对DBP有较强的耐受性和适应性.     

铜、锌、镉对锯缘青蟹仔蟹代谢酶活力影响的实验研究

测定锯缘青蟹仔蟹（背甲宽 ３１.０±３．５ ｍｍ;背甲长 ２３．０±２．８ ｍｍ）暴露在次致死浓度的铜、锌、镉离子溶液下 ２４ ｈ后肝胰腺、鳃、肌肉碱性磷酸酶（ＡＫＰ）、谷雨转氨酶（ＧＰＴ）、谷草转氨酶（ＧＯＴ）的酶活性．结果表明：低浓度重金属使仔蟹酶活力提高,高浓度时又对酶活力有明显的抑制作用．三种金属中,铜、镉对酶活力影响作用较锌显著．三种受试组织中,肝胰腺酶活力最易受重金属影响．     

日本黑褐蚁营养成分分析及两种脱水方法对其SOD、POD、CAT活力的影响

对日本黑褐蚁（Formica japonica Mottschulsky）进行营养成分分析,并对烘干脱水储藏法和冷冻脱水储藏法对其蛋白质及SOD、POD、CAT活力的影响进行了测定对比。结果显示：日本黑褐蚁中粗蛋白含量占鲜重的24.36%,粗脂肪为7.41%,总糖为0.62%,粗灰分为5.36%,粗蛋白占干重达63.6%。两种脱水储藏法对比,烘干脱水法比冷冻脱水法对其蛋白质及SOD、POD、CAT活力的损失更大。     

新疆准噶尔盆地南缘不同生境下的梭梭和柽柳生理生态特性

以在新疆准噶尔盆地南缘自然荒漠区、自然人工交错带、人工种植区等3种不同生境类型下的梭梭(Haloxylon ammodendron(C.A.Mey.)Bge)和柽柳(Tamarix ramosissima Ldb)为研究对象,测定植物叶片的丙二醛(MDA)含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)3种保护酶活性,研究不同生境下梭梭和柽柳的生理生态特性,为准噶尔盆地南缘植被的恢复与重建提供理论依据。结果表明,自然荒漠区和人工种植区的柽柳和梭梭丙二醛含量较多,保护酶活性较高。而自然人工交错带上的植株相对于上述2种样地,丙二醛含量和保护酶活性都较低。结合野外调查和数据分析表明梭梭比柽柳具有更强的耐旱性。     

多菌灵对新疆灰漠土壤中六种酶活性的影响

采用室内模拟的方法研究5种浓度多菌灵（0、2．5、5．0、10．0和20．0mg·kg^-1干土）对土壤中纤维素酶、蔗糖酶、脲酶、碱性磷酸酶、过氧化氢酶、蛋白酶活性的影响。结果表明：土壤纤维素酶活性随多菌灵浓度的增加（2．5～20．0mg·kg^-1）而升高;多菌灵对脲酶也有显著的激活作用,其中10mg·kg^-1多菌灵处理对脲酶的激活率最高。多菌灵对土壤碱性磷酸酶和蛋白酶活性的影响随多菌灵处理浓度和时间变化而变化。多菌灵处理5d内,土壤蔗糖酶活性显著降低,且抑制率与多菌灵浓度呈正相关,土壤过氧化氢酶活性受多菌灵抑制作用显著,尤其是在多菌灵处理26d以后,土壤过氧化氢酶活性随多菌灵浓度的增加显著降低。因此,可以用蔗糖酶活性来评价多菌灵施用后1～5d在土壤中的残留情况,以过氧化氢酶活性来评价多菌灵施用后26～47d在土壤中的残留情况。