水华束丝藻与铜绿微囊藻净化水体氮磷及其脂质积累过程比较

选取水华束丝藻与铜绿微囊藻作为典型水华蓝藻,探索水华蓝藻净化水体及合成生物柴油的潜力.采用氮磷浓度为NH4-N 7.5 mg/L,PO43--P 1.0 mg/L的模拟污水,重点考察了在光照强度与温度不同的条件下2种微藻对氮磷的去除率,并利用尼罗红荧光染色法测定了微藻中的中性脂含量.结果表明,2种藻对PO43--P的去除率均较高,最高达到98％,对NH4+-N的去除率稍低,最高为52％.水华束丝藻及铜绿微囊藻均具有较强积累中性脂的能力,适宜的温度与光照条件有利于微藻对氮磷的去除及细胞中脂类的积累.2种藻均在光照强度为12 000 lx时中性脂含量更高.水华束丝藻在温度为18 ～22℃条件下,生长更优,氮磷净化效果较好,中性脂积累能力更强.而铜绿微囊藻在温度为22～ 26℃时表现更好.     

Antimony induces oxidative stress and cell death in normal hepatocytes

Antimony (Sb) accumulates in the liver which is one of the target organs for metal-mediated toxicity. Although toxicity of Sb was previously investigated, the precise mechanism of Sb-induced hepatotoxicity remains to be determined. The aim of this study was to examine the role of oxidative stress, and mitochondria in the induction of cell death by Sb. Our results showed that liver cell lysis induced by Sb is mediated by reactive oxygen species (ROS) formation, lipid peroxidation and decline of mitochondrial membrane potential (MMP). Antimony-induced ROS formation, lipid peroxidation and reduction of MMP were significantly diminished by antioxidants and ROS scavengers such as dimethyl sulfoxide and mannitol; mitochondrial permeability transition (MPT) pore sealing agents such as carnitine and trifluoperazine; and adenosine triphosphate (ATP) generator, L-glutamine. Antimony-induced ROS formation, lipid peroxidation and fall in MMP were potentiated by glutathione (GSH) depletion via n-bromoheptane. MPT pore sealing agents and ATP generator inhibited hepatotoxicity, indicating Sb-activated cell death via mitochondrial pathway. Pretreatment of hepatocytes with antioxidants and ROS scavengers also blocked cell death induced by Sb, whereas GSH depletion enhances Sb-induced cell death, suggesting that oxidative stress may be directly involved in the reduction of MMP. These findings contribute to a better understanding of the mechanisms that mediate Sb-induced cell death in isolated rat hepatocytes.     

芹菜素对丙烯腈引起大鼠精子脂质过氧化和DNA损伤的影响

分析芹菜素(apigenin,AP)对丙烯腈(acrylonitrile,ACN)引起的大鼠精子脂质过氧化和DNA损伤的影响,并探讨其可能的机制。将50只SPF级SD成年雄性大鼠随机分为阴性对照组(玉米油)、ACN组(50 mg·kg~(-1)ACN)、低AP组(50 mg·kg~(-1)ACN+234 mg·kg~(-1)AP)、高AP组(50 mg·kg~(-1)ACN+468 mg·kg~(-1)AP)、N-乙酰半胱氨酸(N-acetylcysteine,NAC)组(50 mg·kg~(-1)ACN+300mg·kg~(-1)NAC),以5 m L·(kg bw)~(-1)灌胃染毒,1次·d~(-1),6 d·周~(-1),连续13周。检测大鼠精子活性氧(ROS)、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性以及精子DNA损伤情况。结果发现,ACN组、低AP组、高AP组、NAC组精子ROS、MDA含量显著升高,SOD活力显著降低,精子尾部DNA含量百分比、尾长、尾距、Olive尾距均显著增高于对照组(均P0.05);而低AP组、高AP组、NAC组精子ROS、MDA含量、SOD活性和精子DNA损伤情况与ACN组相比差异均无统计学意义(P0.05)。提示ACN可引起大鼠精子脂质过氧化和DNA损伤,而AP、NAC对其无干预作用。     

日粮中铜胁迫对吉富罗非鱼幼鱼抗氧化、脂质过氧化及肝脏组织结构的影响

吉富罗非鱼是我国南方沿海地区水产养殖中的主要经济鱼类之一,但近年来,随着我国城镇化和工业化进程的推进,罗非鱼养殖面临着前所未有的铜富集的挑战。为探明日粮中铜胁迫对吉富罗非鱼幼鱼抗氧化系统和肝脏组织结构的影响,将1 080条罗非鱼幼鱼暴露于6个浓度梯度(0、3、30、300、1 000、3 000 mg·kg-1)的高铜日粮中,通过60 d的暴露试验,实时测定罗非鱼血清与肝脏抗氧化能力,监测肝脏病理变化。结果表明,在本试验条件下,罗非鱼幼鱼血清和肝脏中MDA的含量随日粮中铜含量的增加和胁迫时间的延长显著升高,而SOD、GSH-PX和Cu Zn-SOD的活性表现出先升高后降低的趋势;各组间肝脏表现出不同程度的病变,主要是浊肿变性和脂肪变性,且第Ⅲ、Ⅳ、Ⅴ组肝脏病变严重。综上,日粮中铜胁迫对吉富罗非鱼幼鱼的抗氧化机能有较明显的抑制作用,长时间的暴露能严重损伤其肝脏的组织结构,因此,建议吉富罗非鱼幼鱼日粮中铜的实际含量应控制在42.36 mg·kg-1以下。     

Assessing stress response of Stylophora pistillata towards oil and phosphate pollution in the Gulf of Aqaba,using molecular and biochemical markers

Crude oil (from oil terminal) and raw phosphate (from phosphate port) pollution are responsible for the lowered health conditions of coral reefs at their vicinity in the Jordanian coast of the Gulf of Aqaba. Both in situ incubations and ex situ laboratory exposure experiments were used to study the effects of those pollutants on corals, by using molecular and biochemical biomarkers in the coral Stylophora pistillata. For ex situ part of the experiment, crude oil and raw phosphate were added to a final concentration of 500?ppm for both pollutants. The DNA damage was assessed by Comet assay, while biochemical stress markers were reassessed by lipid peroxidation (LPO) test. Although the corals looked healthy from outside, the use of stress biomarkers indicated that they are under high pressure at the cellular level. The corals incubated with oil and phosphate had more DNA damage and LPO in comparison with the control samples. The results obtained suggest that the use of stress biomarkers can be used as important prognostic tools for examining the sub-lethal stress on corals before their death.     

黄渤海表层沉积物中正构烷烃和甾醇的分布及来源研究

在黄海、渤海湾和莱州湾采集64个表层沉积物样品,分析正构烷烃（C15～C33）和甾醇（菜子甾醇、菜油甾醇、谷甾醇和豆甾醇）的质量分数和分子组合特征,探讨其来源,比较物质来源的空间差异。结果表明：（1）黄海表层沉积物中类脂生物标志物主要呈现陆源和海源共同影响的特征,其中北黄海以陆源输入为主,高碳数正构烷烃（〉C24）具有明显的奇碳优势,陆源高等植物的贡献较大;南黄海陆源输入与海洋自身贡献相当;渤海湾与莱州湾接受来自河流的大量陆源物质;（2）来源于陆源高等植物的甾醇（包括菜油甾醇、谷甾醇和豆甾醇）在黄海表层沉积物中的质量分数远小于渤海湾和莱州湾,但指示硅藻来源的菜子甾醇在整个研究区域均具有较高的质量分数。     

产油脂微藻的分离鉴定及培养条件优化

为促进自养高产油微藻的工业化应用,从青海多种生境中分离到34株产油微藻,以筛选获得产油脂最高的青3-2-2株为出发株,18S rRNA分析表明其与栅列藻属(Scenedesmus sp.)同源性达到99%以上,确定该株属于栅列藻属.研究氮源、培养时间、培养温度、初始pH值等培养条件对微藻生物量及油脂含量的影响,优化培养条件为:硝酸钠为氮源,以10%(V/V)接种量接种于普通SE培养基,培养温度为25℃,初始pH 7.0,培养周期为20 d,可以获得较高的油脂产率,比优化前的产率增加了近70%.     

细菌对城市污水中小球藻生长和油脂积累的影响

利用城市污水培养微藻,可在实现污水无害化处理的同时,培养微藻回收生物质能源.污水为微藻的培养提供氮、磷等营养组分和所需水源,同时污水中的细菌可分解污水中的有机物产生CO_2,为微藻提供生长所需碳源.菌藻混合培养既可以收获藻类,又可以净化污水,由于城市污水含有大量的原生菌类,且微藻与细菌之间存在着互生、拮抗等复杂的相互关系,因此,需要筛选出既能够适应于城市污水又能促进微藻生长和油脂积累的优势菌种.本文从不同来源的13种细菌中筛选出2种能够显著促进蛋白核小球藻(Chlorella pyrenoidosa)生长和油脂积累细菌,并分析了微藻培养结束后城市污水的菌群结构.结果表明:污水中光合细菌初始吸光度D600为0.01,W4菌初始吸光度D_(600)为0.02时,对小球藻的干重和油脂产量促进作用最显著,油脂产量分别可达0.114 g·L~(-1)、0.113 g·L~(-1),油脂产量比空白对照组分别提高了22.58%、21.50%.通过对生成的脂肪酸甲酯进行气相色谱分析,结果显示光合细菌和W4菌的添加并未改变小球藻脂肪酸成分,但提升了单不饱和脂肪酸的含量,有利于提升所得生物柴油的品位.培养结束后污水的菌群结构分析显示投加细菌会降低污水中菌群的丰富度和多样性,初步判断是投加的菌在藻液中能够成为优势菌群,且实验组中丛毛单胞菌属(Comamonas)和假单胞菌属(Pseudomonas)的丰度大于对照组.     

Effect of ingested titanium dioxide nanoparticles on the digestive gland cell membrane of terrestrial isopods

The aim of this study was to find out whether ingested titanium dioxide nanoparticles (nano-TiO₂) cause cell membrane damage by direct contact or by lipid peroxidation. We assessed lipid peroxidation and digestive gland cell membrane stability of animals fed on food dosed with nano-TiO₂. Conventional toxicity measures were completed to determine if cellular effects are propagated to higher levels of biological complexity. An invertebrate model organism (Porcellio scaber, Isopoda, Crustacea) was fed with food containing nanosized TiO₂ and the result confirmed that at higher exposure concentrations after 3 d exposure, nano-TiO₂ destabilized cell membranes but lipid peroxidation was not detected. Oxidative stress as evidenced by lipid peroxidation was observed at longer exposure durations and high exposure doses. These data suggest that cell membranes are destabilized by direct interactions between nanoparticles and cell membrane, not solely via oxidative stress.