不同氮源对2种微藻生长及总脂含量的影响

采用一次培养的方式研究硝态氮（NaNO3）、氨态氮（NH4Cl）、有机氮（尿素）及硝铵混合氮（NH4NO3）（氮浓度17.6 mmol.L-1）对新分离的两株热带淡水微藻——网状空星藻Coelastrum reticulatum及栅藻Scenedesums sp.生长情况及总脂含量的影响。结果表明,2株微藻在不同氮源影响下生长状况不同,并且造成最终的干质量、总脂含量也有较为明显的差异。2种藻添加NaNO3和NH4Cl情况下分别获得了最高的生物量（（0.72±0.08）g.L-1和（0.80±0.03）g.L-1）和最高总脂含量（（38.35±1.32）%和（30.24±3.13）%）。最终二者在添加NaNO3的情况下单位体积总脂产量最高,分别为199.26 mg.L-1和190.76 mg.L-1,均可作为生物柴油的良好来源。     

邻苯二甲酸二乙基己酯(DEHP)对小白鼠肝脏毒性及脂质过氧化损伤

为研究邻苯二甲酸二乙基己酯(DEHP)对小鼠肝脏的毒性及脂质过氧化损伤作用机制,选择昆明4周龄小鼠80只,雌雄各半,随机分为4组。经食饵连续自然给食染毒,于染毒第4周末处死。测量小鼠肝脏和体重的变化,测定不同DEHP染毒剂量组小鼠的血液、肝脏中谷胱甘肽过氧化物酶(GPX)、过氧化氢(H2O2)和丙二醛(MDA),超氧化物歧化酶(SOD)的变化。将实验数据进行ANO-VA分析处理。结果表明,随着染毒剂量的增加,小鼠体重逐渐减少(p<0.01),高剂量组肝脏器系数明显上升(p<0.01)。苏木精-伊红染色法(简称HE染色)可见高剂量组肝脏组织有明显损伤。与对照组相比,DEHP3个剂量染毒组小鼠血液(75mg·kg-1组除外)及肝脏中GPX活性降低(p<0.05,p<0.01),H2O2含量增加(p<0.05,p<0.01);肝组织中(75mg·kg-1组除外)SOD活性降低(p<0.05,p<0.01),MDA含量增加(p<0.01)。以上结果说明DEHP对小鼠肝脏的毒性作用机制可能为脂质过氧化反应。     

太阳辐射减弱对灌浆期冬小麦光合特性及膜脂过氧化水平的影响

以扬麦13为供试材料,通过大田试验方法研究了太阳辐射减弱对冬小麦灌浆期光合生理特性、保护酶系统及膜脂过氧化水平的影响. 设置了5个太阳辐射减弱处理,各处理的太阳辐射强度分别为自然光照的100%(CK),60%,40%,20%和15%. 结果表明:太阳辐射减弱导致冬小麦叶片的光合生理特性发生明显变化,表现为净光合速率(P_n)减少,气孔限制值(L_s)和蒸腾速率(T_r)显著降低,但胞间CO₂浓度(C_i)却逐渐上升;随着太阳辐射减弱程度的增加,冬小麦叶片的CAT(过氧化氢酶),SOD(超氧化物歧化酶)和POD(过氧化物酶)活性均显著增加,表现出较高的抗性,但MDA(丙二醛)含量及EC(电导率)降低,说明太阳辐射减弱未使作物膜系统受到明显伤害;在太阳辐射减弱条件下,冬小麦光合色素的含量增加较明显,但w(Chla)/w(Chlb)下降,对太阳辐射中偏向短波部分波段的吸收能力增强. 综上所述,在太阳辐射减弱条件下,冬小麦灌浆期通过提高保护酶系统的活性避免细胞膜系统的膜脂过氧化伤害,同时提高w(Chlb)以增强光能的利用能力. 尽管如此,由于太阳辐射能量的不足,作物的P_n仍持续下降,且主要是由非气孔因素引起.      

微藻生物膜营养环境对微藻生长和油脂积累影响

以琼脂凝胶作为微藻营养物质的供给源层,微孔滤膜作为微藻生物膜吸附基质,构建了源层/基质层双层结构光合微藻生物膜反应器,研究了微藻生物膜营养环境对微藻生长和油脂积累的影响,实验表明：当琼脂浓度从0.125%（W/W）升高到8%时,生物膜含水量从0.62减少到0.25g,微藻细胞直径从3.87减小到3.35μm,微藻生物膜厚度从91.23降低到62.33μm,单位厚度生物膜内含水量降低40.49%,CO₂和光向生物膜内部传递阻力减小,为光合反应提供充足碳源和光照,微藻生物膜密度从40.56提高了45.86%至59.16g/m²,微藻油脂产量提高了63.39%.     

Effect of a popular Middle Eastern food (Falafel) on rat liver

The aim of this study was to evaluate the effect of short-term consumption of oil and frying oil extracted from falafel patties, and then to study the long-term effect of consumption of falafel patties on rat liver gross morphology and serum liver enzymes. The frying oil quality was assessed using thiobarbituric acid reaction on rat liver homogenate. Frying oil and oil extracted from falafel patties were administered to male Wistar albino rats via gavage for 5 days. Blood samples were collected and the activities of alkaline phosphatase (ALP), aspartate aminotransferase, alanine aminotransferase (ALT), and bilirubin levels were determined. Livers were weighed and gross morphology was assessed. For the long-term effect of falafel consumption, rats were fed falafel patties for 30 days, and then blood samples were collected and assayed for the above-mentioned parameters. Short-term consumption of falafel extracts and frying oil did not cause any significant difference in the liver function tests and liver gross morphology. Whereas, long-term consumption of falafel patties caused a significant increase in ALP, ALT, bilirubin level and increased liver weight/body weight ratio denoting hepatotoxicity. This indicates that consumption of large amounts of falafel on daily basis might lead to hepatotoxicity.     

Vitamins E and C reduce oxidative stress and mitochondrial permeability transition caused by camptothecin – an in vitro study

Camptothecin (CPT), a broad spectrum antineoplastic agent, is known to induce oxidative stress and mitochondria are among the main sources of intracellular reactive oxygen species (ROS). We investigated the merit of vitamins E and C supplementation on CPT-induced mitochondrial alterations in vitro. Following treatment of isolated liver mitochondria with CPT, we assessed the mitochondrial membrane permeability transition (MPT), concentration of malondialdehyde, antioxidants and activities of the enzymes of the respiratory chain and Krebs cycle. Our results provide evidence that CPT caused mitochondrial swelling, increased lipid peroxidation and transition of mitochondrial permeability. The CPT lowered the levels of reduced mitochondrial thiols suggesting that thiol oxidation is the mechanism underlying CPT-induced MPT. Identical experiments were also performed after preincubating the mitochondria with vitamins E and C. It was found that vitamins E and C pretreatment inhibited the deleterious effects of CPT and loss of enzyme activity was restored by antioxidant supplementation. Our results suggest that the toxicity of CPT was mediated by an increase in ROS production by mitochondria. However, the addition of vitamins E or C ameliorated the oxidative stress. We propose that an attempt to counteract the deleterious consequences of chemotherapy with nutritional therapies may be a rational approach in superior patient care especially in a disease like cancer.     

Effect of latex material on antioxidant enzymes,lipid peroxidation,DNA damage,and chromosomal aberration

Cell integrity is affected by oxidative stress when the production of active oxidants overwhelms antioxidant defense mechanisms. Latex, a natural polymer obtained from Hevea brasiliensis, is used in medical industry for manufacturing surgical gloves, urinary catheters, and dental dams. The aim of this study was to evaluate the effects of latex material on oxidative stress by in vivo and in vitro methods. In addition, the material was screened for its ability to induce any chromosomal aberrations (CAs) by in vitro method. In vivo studies were carried out with implanted latex material onto subcutaneous tissue of various batches of experimental Wistar rats. At the end of experimental period, animals were anesthetized, blood was collected for serum analysis, and sacrificed. Liver was excised for the determination of antioxidant enzymes and lipid peroxidation (LPO). Subcutaneous tissues were obtained for the extraction of genomic DNA from implanted animals and checked for the presence of 8-hydroxy-2-deoxyguanosine (8-OHdG), considered an indicator of DNA damage. Simultaneously, in vitro studies were carried out using fresh liver and subcutaneous tissue obtained from Swiss albino mice treated with physiological saline extract of latex material. For the estimation of both in vitro and in vivo oxidative stress, 10% liver homogenate was assessed for stress indicators like reduced glutathione, glutathione reductase, glutathione peroxidase, LPO and protein content. The results of both in vivo and in vitro studies indicated that the chemical leachents from the latex material did not significantly affect LPO and the levels of antioxidant enzymes. There was also no significant increase in 8-OHdG content due to the presence of implanted latex material. Finally, the results of in vitro CA test and G banding indicated that extracts of test material did not induce any chromosomal abnormalities.     

镉和铅对菲律宾蛤仔脂质过氧化及抗氧化酶活性的影响

为了研究亚致死浓度的重金属对海洋贝类的毒性效应,探讨其可能的作用机理,在实验生态条件下以菲律宾蛤仔(Ru-ditapes philip pinarum)为目标生物,采用半静态毒性实验方法,研究了不同浓度Cd2+(0.0948、0.237和0.474mg·L-1)和Pb2+(0.276、0.690和1.380mg·L-1)对菲律宾蛤仔鳃和消化腺组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性以及丙二醛(MDA)含量的影响。结果显示:(1)鳃和消化腺中的抗氧化酶及MDA的变化呈现出类似的趋势,在胁迫初期,各浓度处理组菲律宾蛤仔鳃和消化腺组织SOD和CAT与对照组相比活性都显著升高(P<0.01),呈现出明显的诱导效应,而MDA含量与对照组相比差异不显著(P>0.05);随着胁迫时间的延长,高浓度Cd2+(0.474mg·L-1)和Pb2+(1.380mg·L-1)处理组中SOD、CAT活性快速下降,与对照组相比差异显著;低浓度处理组中的抗氧化活性虽然也较对照组有所下降,但总体下降幅度不如高浓度组明显,并且所历暴露时间较长。各浓度处理组中MDA含量变化一致,均呈现出先升高后降低的趋势,且含量均高于对照组。(2)通过相关性分析,菲律宾蛤仔消化腺组织中的SOD活性与Cd2+浓度的相关性大于鳃组织,与Pb2+浓度的相关性则小于鳃组织;消化腺组织中的CAT活性与Cd2+、Pb2+浓度呈抛物线型相关,与鳃组织CAT活性相关性不十分显著。这说明消化腺组织中SOD活性对Cd2+的敏感性大于鳃组织,消化腺组织中CAT活性对Cd2+、Pb2+的敏感性大于鳃组织。因此,菲律宾蛤仔消化腺中SOD、CAT对水环境中的重金属反应敏感,且存在一定的剂量-效应关系,消化腺组织中SOD和CAT活性与其他敏感性指标一起可以作为指示早期海洋重金属污染的生物标志物。     

Atmospheric stability and PM10 concentrations at far distance from elevated point sources in complex terrain: worst-case episode study

Atmospheric stability is the most important parameter affecting dilution of air pollutants. It plays a very important role in the investigation of parameters that affect ambient pollutant concentrations, especially in the case of complex terrain areas. In this study, the classification of atmospheric stability by Pasquill-Turner classes and any associated variation of ambient PM10 (particles with aerodynamic diameter<10 microm) concentrations for a region of complex terrain is investigated. Real experimental meteorological and PM10 data are used for a 2-year period from one observation station far distant from the main stack sources and they are related with the classified atmospheric stability categories in an hourly and monthly based distribution. A more detailed analysis is carried out during PM10 episodes for the same period in order to reveal the governing worst-case atmospheric conditions.     

五氯硝基苯对小鼠脑AChE的影响及多器官氧化损伤研究

测定五氯硝基苯(PCNB)对小鼠脑乙酰胆碱酯酶(AChE)的影响及多器官的氧化损伤作用.对昆明种小鼠采用灌胃法进行200,400和600 mg·kg-1三个剂量染毒,每日一次,分别于染毒4,8,12和16d测定AChE活性、过氧化氢酶(CAT)活性和脂质过氧化(LPO)产物丙二醛(MDA)的含量.结果表明:(1)小鼠脑AChE活性受到抑制,并表现为明显的时间和剂量依赖性;(2)肝、肾CAT活性变化显著,脂质过氧化作用明显;(3)高剂量毒物在染毒16d时对脾脏脂质过氧化作用明显增强;(4)脑和血清CAT活性随染毒时间延长先升高后降低,脂质过氧化作用不明显.PCNB对小鼠可能具有神经毒性,对肝、肾脏的氧化损伤作用较强.