久效磷对海洋微藻毒性机理的初步研究Ⅲ.超氧化物歧化酶和过氧化物酶活性的变化

报道了久效磷对３种海洋微藻细胞内２种清除活性氧的关键性酶－超氧化物歧化酶和过氧化酶活性的影响。结果显示：１．在久效磷的胁迫下，扁藻和三角褐指藻细胞的超化物歧化酶活性均表现出下降的总变化趋势，而叉鞭金藻细胞的ＳＯＤ活性时而上升，时而下降，在整个胁迫过程中呈现出无规律性的变化。２．随着久铲磷胁迫时间的延长，３种微藻细胞的过氧化酶活性均逐渐下降，表现出相同的变化规律性。     

凤眼莲根系分泌物对栅藻结构及代谢的影响

研究了凤眼莲（Ｅｉｃｈｈｏｒｎｉａ ｃｒａｓｓｉｐｅｓ）根系分泌物对栅藻（Ｓｃｅｎｅｄｅｓｍｕｓ ａｒｃｕａｔｕｓ Ｌｅｍｍ）超微结构及生长代谢的影响，结果显示，凤眼莲对栅藻有明显的克生作用，藻的数量逐步减少，栅藻生长受影响后，细胞中绿体片层肿用甚至解体，线粒体嵴消失，质膜、核膜受破坏，光合放氧化速度明显下降，可溶性蛋白折含量四天后４线下降，超氧阴离子（Ｏ２－）、丙二醛（ＭＤＡ）的含量上升，知值都     

SEDIMENT OXYGEN DEMAND IN THE ARROYO COLORADO RIVER1

ABSTRACT: The lower reaches of the Arroyo Colorado have historically failed to meet their use under subsection 303(b) of the U.S. Clean Water Act due to fecal coliform bacteria and low dissolved oxygen (DO). Fish kills, especially at the tidal confluence at the Port of Harlingen, Texas, have been reported. Oxygen demand from sediment (SOD) for a river typically has two states‐diffusion limited SOD (SOD) and potential SOD (pSOD), expressed when sediment is resuspended through increased flow or other disturbances. The objective of this research was to measure SOD in the Arroyo Colorado River in situ, estimate pSOD ex situ, and evaluate the relationship between SOD and the depositional environment. We measured SOD and pSOD in the Arroyo Colorado River at up to eight sites over three sampling events. We identified the sample sites based on a modified Rosgen geomorphic index for streambed stabilization. Sites with high sediment deposition potential had high SOD. The average values of SOD between sites were 0.62 g/m²/day (standard deviation 0.38 g/m²/day) and ranged from 0.13 to 1.2 g/m²/day. Potential SOD values ranged from as low as 19.2 to as high as 2,779 g/m³ sediment/ day. Potential SOD can serve as an indicator of the possible impact of SOD from resuspended sediment in stream systems.     

非潮汐淹水对白骨壤膜脂过氧化系统的影响

通过室内模拟非潮汐淹水,探索不同淹水水位条件下,红树植物白骨壤(A.marina(Forsk.)Vierh).超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)随时间的变化情况。结果表明,经历第二个淹水周期后,较第一个周期各梯度,白骨壤超氧化物歧化酶活性(SOD)从高到低排序不变,过氧化氢酶活性(CAT)、丙二醛的量(MDA)也表现出相同的规律。本研究结论为红树植物在人工非潮汐生境下,红树林造林的关键技术之一——淹水水位的控制提供了数据参考。     

活性污泥中超氧化物歧化酶(SOD)活性测定影响因素

研究以污水生物处理中的活性污泥为对象,采用氮蓝四唑光还原法测定超氧化物歧化酶(SOD)活性,从样品制备和保存方面探讨了是否添加溶菌酶液、细胞破碎时间、酶液保存时间与保存温度等因素对SOD活性测定的影响。研究表明,溶菌酶液的加入提高了细胞破碎效果;细胞破碎的条件为99次(工作3 s,停3 s),时间为40 min时破碎效果最好;酶液保存时间在4 h内最佳;-20℃保存比4℃保存对酶活性影响小。最佳检测条件为:取样量为1 mL时,反应温度为30℃,反应时间为20 min时,SOD酶活性最大。     

Hydroxytyrosol, the phenolic compound of olive oil protects human PBMC against oxidative stress and DNA damage mediated by 2,3,7,8-TCDD

The protective effect of hydroxytyrosol (HT), a strong antioxidant compound from extra virgin olive oil, against TCDD induced toxicity was investigated in human peripheral blood mononuclear cells (PBMC). PBMC (1 × 10⁶ cells mL⁻¹) were divided into four groups and were incubated in a CO₂ incubator (5% CO₂) for 12 h with vehicle, TCDD (10 nM), TCDD + HT (10 nM + 100 μM) and HT alone (100 μM) respectively. To clarify the role of HT against TCDD induced cytotoxicity, oxidative stress and the levels of antioxidant enzymes were assessed. Incubation of PBMC with TCDD significantly decreased cell viability, catalase (CAT) and glutathione peroxidase (GPx) and increased the levels of superoxide dismutase (SOD), glutathione reductase (GR) and oxidative stress markers such as lipid peroxidation products (LPO), protein carbonyl content (PCC) and reactive oxygen species (ROS). Whereas, HT had an effective antioxidant property as observed by the increased cell viability, normalization of antioxidant enzymes and decreased levels of LPO, PCC and ROS in PBMC co-treated with HT and TCDD. Apoptosis detection and comet assay results shows that HT, by acting as an antioxidant, prevents the damage to DNA induced by TCDD. In addition light microscopic and histopathological observations revealed that the cells are apoptotic and degenerated during TCDD treatment, whereas cells showed intact morphology during co-treatment with HT. On the whole, the results reveal that HT exerts a promising antioxidant potential in protecting the PBMC against TCDD induced oxidative stress, which might be due to the presence of catechol moiety in its structure.     

Plant steroid hormones produced under Ni stress are involved in the regulation of metal uptake and oxidative stress in Brassica juncea L

Brassinosteroids (BRs) are involved in the amelioration of various biotic and abiotic stresses. With an aim to explore the role of BRs under heavy metal stress, plants of Brassica juncea L. were grown in pots. The plants were subjected to various concentrations of Nickel metal (0.0, 0.2, 0.4 and 0.6 mM) and harvested on 60th day in order to observe the expression of these hormones. The isolated BRs from the leaves of Brassica plants characterized by GC-MS include 24-Epibrassinolide (24-EBL), Castasterone, Dolicholide and Typhasterole. The effect of isolated 24-EBL was studied on Ni metal uptake and antioxidative defense system in 60 d old plants of Brassica. It was observed that 24-EBL significantly increased the activities of stress ameliorating enzymes and lowered the metal uptake in plants. This is the first report in B. juncea L. plants showing the expression of BRs under metal treatments and effect of the isolated 24-EBL on metal uptake and in oxidative stress management.     

Zn^2＋对水鳖的毒性作用

研究了不同浓度Zn^2 毒害对水鳖叶片膜脂过氧化作用及其体细胞超微结构的影响。结果表明,随着Zn^2 浓度的增加,叶绿素含量、SOD、CAT、POD活性先后升降,叶绿素a/b值值则逐渐减小,而MDA含量增加,O2^-产生速率也逐渐增大。同功酶分析表明,Zn^2 可以诱导新的POD同功酶,电镜观察发现,低浓度Zn^ 处理下,水鳖叶细胞中核质空泡化,叶绿体膨胀变形,线粒体嵴膨胀,溶酶体、小泡数量增加,且出现了多膜复合体;随着Zn^2 浓度的增加,核质消失,叶绿体和线粒体解体,而根尖分生细胞中则出现了多核仁现象。