不同浓度Cd对小白菜生长及抗氧化系统的影响

采用温室水培试验方法,研究了不同浓度Cd对小白菜生长、叶绿素含量和叶片中抗氧化系统的影响。结果表明,Cd浓度为0.01mg·L-1时促进小白菜生长;Cd浓度为10mg·L-1时,抑制小白菜生长;与对照相比,0.01、0.1mg·L-1Cd处理后,叶绿素a与叶绿素b的含量增加;Cd浓度达到1mg·L-1时,叶绿素a与叶绿素b的含量显著下降(P<0.05)。超氧化物岐化酶(SOD)的活性随Cd处理浓度的增加而下降;愈创木酚过氧化物酶(GPOD)、抗坏血酸过氧化物酶(APX)在Cd浓度为0.1mg·L-1时活性最高;过氧化氢酶(CAT)在Cd浓度为1mg·L-1时活性达到最高;脱氢抗坏血酸还原酶(DHAR)、谷胱甘肽还原酶(GR)的活性和抗坏血酸(AsA)、还原型谷胱甘肽(GSH)的含量在Cd处理浓度为10mg·L-1时最高。

箱式气调贮藏对鲜切富士苹果抗氧化系统的影响

以富士苹果为试材,研究了鲜切富士苹果在5℃的5%O2+5%CO2或5%O2+10%CO2箱式气调贮藏条件下抗氧化系统的变化情况。每3d测定1次酶促防御系统的酶活性和非酶促防御系统的抗氧化物质的含量,并测定呼吸速率、腐烂率和褐変情况。结果表明:与对照相比,2种CO2浓度的箱式气调贮藏条件均可启动酶促防御系统,使过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性得到提高,同时也加速了非酶促防御系统抗氧化物质的消耗,降低了总酚和Vc含量以及贮藏中后期的还原型谷胱甘肽(GSH)含量。2种浓度的CO2处理可有效减慢呼吸速率,抑制腐烂的发生并有效降低褐变程度,其中5%O2+5%CO2更有利于鲜切富士苹果褐変的控制,而5%O2+10%CO2更有利于抑制腐烂。

Free radicals generation in an in vitro fertilization setting and how to minimize them

Several studies report an increase in both male and female factors in infertility worldwide. In recent years there has been a tremendous increase in couples seeking assisted reproductive technology(ART) procedures in order to have children. However, the success rates of these procedures still remain very low. One of the major contributing factors to the low success rate in ART has been the damage caused by free radicals to the gametes and the developing embryo. The manipulation of gametes and embryos in an in vitro environment when performing assisted reproductive techniques carries the risk of exposure of these cells to supraphysiological levels of free radicals; namely, reactive oxygen species(ROS) and reactive nitrogen species. Oxidative stress can originate from the early steps of ART involving the oocyte, sperm and embryo, as well as in the endometrial environment later on following embryo transfer. The common sources of free radicals in an in vitro fertilization setting include the developing embryo, spermatozoa and leukocytes, semen centrifugation, oxygen partial pressure, light, culture media and cryopreservation/thawing. These free radicals are measured using different techniques, such as the cytochrome C reduction method and chemiluminescence-based techniques. Different efforts are being employed to minimize theexcess generation of free radicals in the ART setting, with the aim of improving the success rate, and antioxidant supplementation has emerged as one of the viable routes. Moreover, it is very important to inform ART personnel about the sources of ROS in the laboratory so that they can stop the use of procedures that are deleterious and start to use safer procedures.

Apoptotic signaling through reactive oxygen species in cancer cells

Reactive oxygen species(ROS) take part in diverse biological processes like cell growth,programmed cell death,cell senescence,and maintenance of the transformed state through regulation of signal transduction. Cancer cells adapt to new higher ROS circumstance. Sometimes,ROS induce cancer cell proliferation. Meanwhile,elevated ROS render cancer cells vulnerable to oxidative stress-induced cell death. However,this prominent character of cancer cells allows acquiring a resistance to oxidative stress conditions relative to normal cells. Activated signaling pathways that increase the level of intracellular ROS in cancer cells not only render up-regulation of several genes involved in cellular proliferation and evasion of apoptosis but also cause cancer cells and cancer stem cells to develop a high metabolic rate. In over the past several decades,many studies have indicated that ROS play a critical role as the secondary messenger of tumorigenesis and metastasis in cancer from both in vitro and in vivo. Here we summarize the role of ROS and anti-oxidants in contributing to or preventing cancer. In addition,we review the activated signaling pathways that make cancer cells susceptible to death.

The Impact of Microbial Transglutaminase on the Quality and Antioxidant Activity of Camel-Milk Soft Cheese

This study aimed at investigating the impact of adding microbial transglutaminase (MTGase) after rennet addition on some properties of fresh soft cheese made from camel milk. MTGase was added to milk at concentration of 80, 100 and 120 U/L after 20 and 30 min of renneting. The chemical composition, yield, hardness, antioxidant activity and sensory properties of cheese were estimated. Enzymatic protein crosslinking was analyzed by SDS-PAGE. Results revealed that MTGase-treated cheeses were higher in moisture and lower in protein content compared to control. In addition, the concentration of MTGase and time of addition significantly (P 0.05) impacted these parameters. Among treated cheeses, samples with 80 U of MTGase and addition time of 20 min were the highest in total solids and protein content. Adding MTGase significantly (P 0.05) increased the cheese yield, however, increased MTGase concentration at any time of addition did not improve it. The electrophoretic patterns of MTGase-cheese proteins showed a reduction in the intensity of caseins bands and the appearance of new protein fractions with high molecular weights. However, the changes in the intensity of the whey proteins bands were not sufficiently clear as caseins. The cheese hardness was significantly (P 0.05) affected by adding MTGase. Cheese containing 80 U of MTGase had the highest hardness value compared to control and other treated samples. The antioxidant activity of cheese was negatively influenced by adding the enzyme. The use of MTGase enhanced the mouthfeel, texture and overall acceptability of cheese. However, the effect of MTGase concentration and addition time was not significant (P > 0.05) on the sensory attributes. In conclusion, adding MTGase to milk at concentration of 80 U after 20 min of renneting is recommended to improve the yield, textural and some sensory properties of fresh soft cheese made from camel milk.

纳米TiO_2对杉木种子萌发和幼苗生长及生理的影响

本文以杉木种子和纳米TiO_2为实验材料,研究不同浓度(50、100、500、1000 mg·L-1)纳米TiO_2溶液对杉木种子萌发、幼苗生长及生理特性的影响,探究纳米材料对林木种子萌发及幼苗生长发育的调节作用。结果显示:纳米TiO_2溶液对杉木种子发芽率、发芽势、发芽指数、活力指数均有促进作用,促进作用随处理浓度的增加呈现先增强后减弱的趋势,且100 mg·L^(-1)溶液处理对种子发芽指标提高效果最佳,分别比对照增加66%、92%、71%和299%;杉木幼苗的鲜重和根长均在100 mg·L^(-1)时达到最大值,分别比对照显著增加35%和143%。500 mg·L^(-1)纳米TiO_2溶液处理显著提高了CAT、SOD和POD活性,分别比对照提高108%、488%、182%,但降低了MDA含量(降低82%)。研究表明,适当浓度纳米TiO_2溶液处理不但能有效促进杉木种子萌发与幼苗生长,而且能改善幼苗的生理功能,可能会增强其对逆境的适应能力。

Analysis of the phytochemical contents and antioxidant activities of crude extracts from Tulbaghia species

OBJECTIVE: To assess the phytochemical contents and antioxidant activities of crude extracts from selected Tulbaghia species.METHODS: Standard methods were used for preliminary phytochemical analysis. The total phenolic acid contents of the plant extracts were determined using the Folin-Ciocalteu method, and the total flavonoid contents were determined using the aluminum chloride colorimetric method. 1,1-Diphenyl-2-picrylhydrazyl and 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assays were used to evaluate the antioxidant activities.RESULTS: Phytochemical screening showed flavonoids, glycosides, tannins, terpenoids, saponins,and steroids were present in the Tulbaghia species.The total phenolic acid and flavonoid contents varied in the different plant extracts, ranging from4.50 to 11.10 mg of gallic acid equivalents per gram of fresh material and 3.04 to 9.65 mg of quercetin equivalents per gram, respectively. The IC50 values determined for Tulbaghia alliacea and Tulbaghia violacea based on 1,1-diphenyl-2-picrylhydrazyl(0.06 and 0.08 mg/m L, respectively) and 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)(0.06 and 0.03 mg/m L, respectively) were low and showed they had potential antioxidant activities.CONCLUSION: Our results suggest that individual compounds from Tulbaghia species should be isolated for analysis of their antioxidant activity because some compounds may work best when pure.

Effect of Zibushenjing Fang on skeletal development and brain tissue antioxidation in mice with kidney essence insufficiency: a mechanistic study

OBJECTIVE: To investigate the effects of Zibushenjing Fang (formula for tonifying the kidney essence) on skeletal development and brain tissue antioxidation in mice with kidney essence insufficiency. METHODS: Fifty male Kunming mice were randomly divided into five groups: normal group, model group, Jinkuishenqi Wan group, Zibushenjing Fang high dose group, and Zibushenjing Fang low dose group, with 10 mice in each group. The model of kidney essence insufficiency syndrome was established in all the mice except the normal group by using a cat to threaten the mice and by swimming until exhaustion daily which lasted about 21 days. Mice in the model group were administered 20 mL/ kg -1 · d -1 of normal saline intragastrically. The Jinkuishenqi Wan group was given 2.7 g/kg-1 · d-1 ofa solution of Jinkuishenqi Wan. The Zibushenjing Fang high dose group was given 20 g/kg -1 · d -1 and the Zibushenjing Fang low dose group was given 10 g/kg -1 · d -1 of a solution of Zibushenjing Fang.The general condition of all the groups was observed, including the quantity of food and water intake, swimming time, length of femur, and weight of the femur and musculus quadriceps femoris. The total superoxide dismutase (T-SOD), glutathione peroxi- dase (GSH-Px), and methane dicarboxylic aldehyde (MDA) activities in the brain tissues were detected. RESULTS: Zibushenjing Fang could improve the manifestation of kidney essence insufficiency, increase the quantity of food and water intake, swimming time, femur length, and femur and musculus quadriceps femoris weight. It could also regulate the activities of T-SOD, GSH-Px, and MDA in brain tissue. CONCLUSION: Zibushenjing Fang may play an important role in treating kidney essence insufficiency syndrome by promoting body development and improving brain tissue antioxidation.