利用不同植物进行DNA损伤彗星实验的方法比较

为了研究彗星实验在植物DNA损伤检测中的应用,以多种植物材料为对象,进行了植物彗星实验的比较研究.分别分离了蚕豆、菠菜、洋葱、菜豆、大蒜、水稻等植物组织的细胞核,并以彗星实验方法研究了H2O2引起的植物细胞核DNA损伤.电泳后发现H2O2处理组植物细胞核出现明显拖尾,而对照组没有出现拖尾或拖尾较小.研究结果表明彗星实验是一种可以在单细胞水平上研究植物DNA损伤程度的手段,具有灵敏、简单、快速的优点.采用合适的细胞核分离方法,能够将彗星实验应用于多种植物,研究其DNA损伤.蚕豆、菠菜、洋葱、菜豆、大蒜等植物的根尖和叶片都可以应用于植物彗星实验,但在本实验条件下利用水稻组织进行彗星试实验并没有获得明显的彗星图像,能否进行彗星实验可能受植物本身性质或实验条件等多种因素的影响.     

彗星实验技术及其应用

彗星实验是瑞典科学家Ostling和Johanson于1984年发明的检测毒物DNA损伤效应的方法。它经历了从最初的微电泳技术、中性彗星实验、碱性彗星实验、酶切彗星实验和双向垂直彗尾彗星实验等不断完善的发展过程。在毒理学、遗传学和环境生态科学等领域有着重要的应用,是经济合作与发展组织(OECD)和欧洲食品安全局等国际组织推荐的测定遗传毒性的方法之一。彗星实验的关键点包括单细胞悬液的制备、细胞裂解液的成分与比例,低熔点琼脂糖凝胶的浓度,电泳条件等。在典型应用领域,如蚯蚓、鱼、两栖动物、鼠和人的彗星实验很难找到标准实验方案。成功的彗星实验还需关注,实验设计时必须包括阳性对照,结果表述时必须有图为证,实验方案可能因物种或细胞而异。     

基于彗星实验的洛克沙胂对秀丽隐杆线虫胚胎细胞DNA损伤的研究

为评价洛克沙胂的遗传毒性,采用单细胞凝胶电泳(彗星实验),研究了不同浓度的洛克沙胂对秀丽隐杆线虫胚胎细胞脱氧核醣核酸(DNA)的损伤作用。提取秀丽隐杆线虫的胚胎细胞,分别暴露于0(空白对照)、50、250、500μg·L~(-1)含洛克沙胂的溶液染毒1 h。用彗尾DNA百分比含量(TDNA%)、彗星尾长(TL)和Olive尾矩(OTM)作为DNA损伤的指标。实验结果表明,与空白对照组比较,处理组中彗尾DNA百分比含量、彗星尾长以及Olive尾矩显著增加(P0.01)。随着洛克沙胂浓度的增加,彗尾DNA百分比含量、彗星尾长以及Olive尾矩逐渐增加,其相关系数r0.99,说明在实验浓度范围内,存在极显著的浓度-效应关系。洛克沙胂对秀丽隐杆线虫胚胎细胞DNA具有损伤作用,彗星实验操作简便、快速、灵敏度高,能够反映出洛克沙胂的遗传毒性。因此,通过彗星实验建立实验室检测洛克沙胂遗传毒性的方法具有可行性。     

二氧化硫亚慢性染毒对大鼠肺细胞DNA的损伤

为了探讨低浓度SO2长期暴露对哺乳动物肺细胞DNA的影响,采用动式吸入法(SO2浓度为28mg/m3)对Wistar大鼠染毒30d,运用单细胞凝胶电泳技术(彗星试验)研究了SO2亚慢性染毒对大鼠肺细胞DNA的损伤作用.结果表明,SO2可引起雌、雄性大鼠肺细胞核DNA迁移长度显著增加(P<0.01),且SO2对雄性小鼠肺细胞DNA损伤比雌性小鼠严重;经染毒后,与对照组相比,大鼠的体重减轻,肺体比增加.这些结果表明,较低浓度的SO2也具有引起哺乳动物肺细胞DNA突变的潜在危险.表3参15     

原油降解细菌ODB01的筛选、鉴定及降解特性

从长庆油田被原油污染土壤中筛选出1株以原油为唯一碳源的菌株ODB01。经菌株生理生化特征及16S r DNA序列分析,鉴定为肠杆菌属(Enterobacter sp.)细菌;运用响应曲面法优化细菌ODB01对原油的降解条件为p H值为8.91,w(NaCl)为1.19%,油菌比为1∶4.12,温度为36.78℃,在该条件下细菌ODB01对原油的降解率为34.6%;分别添加w=0.05%土温80(Tween 80)和w=0.05%辛基苯基醚(Triton X-100)后,细菌ODB01对原油降解率分别达到42.5%和46.1%。结果表明,细菌ODB01对原油具有一定的降解能力,有望作为一种微生物修复剂进行开发。     

基于表面增强拉曼光谱技术的环境水样中杀鼠醚的现场快速检测方法

杀鼠醚在水环境中的蓄积可对生态系统造成破坏,并对人体健康产生不利影响.本文利用表面增强拉曼光谱(SERS)技术,构建环境水中杀鼠醚的简单、快速定性及定量检测分析方法.采用化学合成法制备了粒径为45—60 nm的纳米金作为SERS活性基底,以便携式拉曼光谱仪作为检测平台,实现了3 min内完成环境水中杀鼠醚的检测.通过对实验条件进行优化,该方法的检出限低至1.53 ng·mL^-1,加标回收率为90.2%—98.2%.在浓度为0.025—5μg·mL^-1范围内,杀鼠醚浓度与SERS信号强度间呈现出良好的线性关系,R²=0.990.与传统方法相比,该方法操作简单、快速、成本低廉,为水中杀鼠醚的现场检测分析提供了可靠的新选择.     

磁性纳米羟基磷灰石对污染土壤中镉的吸附—移除效果

为从污染土壤中吸附移除重金属镉(Cd),将共沉淀法合成的磁性纳米羟基磷灰石(nHAP@Fe₃O₄)分别按0、0.1%、0.5%、1.0%、3.0%比例添加至土壤中,在修复21、30、45 d时,磁分离nHAP@Fe₃O₄与土壤,考察nHAP@Fe₃O₄对土壤Cd的去除、材料的回收效果及修复后土壤理化性质的变化。结果表明,w(Cd)为2.510 mg·kg^-1的重污染稻田土壤中添加1.0%nHAP@Fe₃O₄,修复21 d时土壤Cd去除和材料回收效果最好,Cd平均去除率和材料回收率分别为16.45%和85.33%;nHAP@Fe₃O₄能明显降低土壤Cd的可交换态,促使其向较稳定的形态转化;经nHAP@Fe₃O₄修复后的土壤pH值升高,CEC有所降低,土壤颗粒间孔隙增大。利用磁性将nHAP@Fe_3<...     

茶多酚对三丁基锡诱导的小鼠氧化损伤的保护作用

为研究茶多酚对三丁基锡诱导的小鼠氧化损伤是否具有保护作用,采用灌胃方法,对雄性小鼠进行TBT染毒, 然后分别用不同剂量的茶多酚进行保护．结果表明,茶多酚保护组小鼠肝组织活性氧(ROS)活性和丙二醛(MDA)含量均明显低于TBT对照组;彗星实验发现茶多酚保护组小鼠淋巴细胞尾长较正常,而尾相与TBT对照组相比没有显著改变．电镜观察结果表明茶多酚保护组胸腺细胞核和线粒体损伤明显减轻．因此茶多酚对TBT诱导的氧化损伤具有一定的预防作用,并且对细胞核损伤也有一定的保护作用．茶多酚对TBT所引起的细胞核损伤的保护作用机制可能是抑制脂质过氧化反应,防止细胞氧化损伤,从而保护DNA．     

次氯酸钠催化氧化法处理十二碳硫醇恶臭污水

采用活性炭和次氯酸钠催化氧化处理含有十二碳硫醇的恶臭污水,进行了小试并取得了良好的效果。在活性炭作催化剂,反应温度为100℃,反映时间为2-3min的实验条件下,1mL1%(m/v)NaClO即可处理100mL污水,处理后的废水无色无臭,可直接排放。     

盐碱地农-渔开发对土壤环境的影响

在东北苏打盐碱地进行了稻-鱼-苇-蒲开发试验,并探讨了该模式对盐碱土壤环境的影响。结果表明,开发后土壤有机质含量增加96.8%(平均值,以下同),盐分含量下降43.6%,全量和速效N、P、K质量分数分别增加142.8%和188.2%;阳离子交换量、盐基总量分别增加8.21%及27.71%;土壤腐殖质以富里酸为主,w(HA)/w(FA)比值提高36.15%;养鱼稻田的土壤微生物总量明显高于未养鱼田(P<0.01);优势种为放线菌。土壤酶活性进一步加强。系统废水的盐分质量浓度降至1.0 g/L左右,碱浓度低于水源(7.0~10.0 mmol/L)。该模式不会造成土壤次生盐碱化。     

Absolute configuration of the major sex pheromone component of the satin moth, Leucoma salicis, verified by field trapping test in Hungary

Summary. Male satin moths, Leucoma (Stilpnotia) salicis L. (Lepidoptera, Lymantriidae) were attracted only to (3Z,6R,7S,9R,10S)-isomer out of the four (3Z)-cis-6,7-cis-9,10-diepoxy-3-henicosenes (leucomalure). This was demonstrated by field trapping test with a bivoltine population in a mixed poplar-willow forest along the flood area of the river Danube at Adony, Hungary.     

Characterization of the benthic vegetation in the Farwà Lagoon (Libya)

This study forms part of the Action Plan for the Conservation of Marine Vegetation in the Mediterranean SEa (United Nation Environmental Program). It was carried out in June 2000 in the Farwà Lagoon, Libya. The mapping of the main benthic vegetation was achieved by compiling the field observations (transect method), and remote sensing of SPOT satellite images. The phytobenthos in the Farwà lagoon covers an area of 1820 ha (65%). Three benthic macrophyte species dominate, namely the marine phanerogamsCymodocea nodosa andPosidonia oceanica, and the algaCaulerpa prolifera. DeadPosidonia oceanica leaves (litter) form veritable mounds in the vicinity of the openings leading to open sea. These leaves, which come from the coastal sea, are brought into the lagoon by currents and tides; their decomposition will lead to high oxygen consumption and the release of hydrogen sulphide. The phenological data ofPosidonia oceanica shoots sampled in the lagoon are similar to those from other stations in the Mediterranean. Conversely, the lepidochronological parameters of shoots sampled in the central part of the lagoon exhibit values that are substantially higher than those generally recorded in the Mediterranean. The mean number of leaves produced annually is 9.9 (mean value for the Mediterranean: 7.5) and the rhizome growth rate is of 35.7 mm.yr⁻¹ (mean value for the Mediterranean: 7.5 mm.yr⁻¹). This hypersaline environment would seem to provide optimum growth conditions for the speciesPosidonia oceanica.     

Volatiles of the honey bee larva initiate oogenesis in the parasitic mite Varroa destructor

Summary. Varroa reproduction is closely synchronized to the development of its host. In this study we present a new bioassay for field and laboratory tests to evaluate host factors triggering Varroa oogenesis. Female mites deprived of feeding activated oogenesis when perceiving larval volatiles. In laboratory assays the living L5-larva and pentane extracts of the larval cuticle had a clear activating effect. Wax and larval food did not elicit Varroa oogenesis. The activating components apparently are in the polar fraction of the cuticular volatiles. The consequences of this regulative mechanism for the host parasite relationship and prospects for further research are discussed.     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Extension of twoCaulerpa species along the Tunisian coast

Two species of the green alga genusCaulerpa are considered as invasive in Tunisia:Caulerpa racemosa andC. taxifolia. C. racemosa is found in a many new localities at the central and southern Tunisian coast, and even in the North of the country in colder water. These new observations lead to the hypothesis of the multiplicity of the origins of the introduction of the species and suggest possible invasive potentialities. The general thallus, and more particularly the number, the shape as well as the arrangement of ramelli on fronds allowed us to identify four morphologically different groups. These groups could be either different systematic entities or polymorphic variations of the same taxon due to different ecological conditions.Caulerpa taxifolia was observed for the first time in Tunisia at the roadstead of Sousse in the beginning of the year 2000. It is recognized as identical to that found in the other Mediterranean localities (GenBank number AJ228960). Up to the end of March 2000, a submarine prospecting campaign revealed an affected area of about 350 ha in front of 2 km of coast. Colonies ofCaulerpa taxifolia disseminating in this area appear in isolated spots. form, In the growing stage, they form surfaces varying between 0.5 to 6 m² and located 20 to 100 m from each other. The total covered surface was estimated to be between 0.5 and 1 ha.     

High genetic diversity of the symbiotic dinoflagellates in the coral Pocillopora meandrina from the South Pacific

Symbioses between dinoflagellates in the genus Symbiodinium (commonly referred to as zooxanthellae) and scleractinian corals are an essential feature for the maintenance of coral reefs. The fine-scale diversity and population structure of the zooxanthellae inhabiting the coral Pocillopora meandrina, a major reef building species in Polynesia, was examined. We used two polymorphic microsatellites to study seven populations from the South Pacific, whose host structuring has been previously investigated. The symbionts of P. meandrina showed high levels of diversity, with more than one zooxanthella genotype being identified in most of the host individuals. Genetic differentiation between symbiont populations was detected at a large scale (2,000 km) between the Tonga and the Society Archipelagos. Within the Society Archipelago, the two most remote populations (Tahiti and Bora-Bora; 200 km apart) were only weakly differentiated from each other. Statistical tests demonstrated that the symbiont genetic structure was not correlated with that of its host, suggesting that dispersal of the symbionts, whether they are transported within a host larva or free in the water, depends mainly on distance and water currents. In addition, the data suggests that hosts may acquire new symbionts after maternal transmission, possibly following a disturbance event. Lastly, the weak differentiation between symbiont populations of P. verrucosa and P. meandrina, both from Moorea, indicated that there was some host-symbiont fine-scale specificity detectable at the genetic resolution offered by microsatellites.     

Phototransformation and ecotoxicity of the drug Naproxen-Na

The phototransformation of naproxen Na in aqueous medium has been investigated. Irradiation of the drug in drinking water affords seven photoproducts. Three of them are dimeric photoproducts isolated for the first time. The compounds, isolated by chromatographic processes, have been identified by spectroscopic means. The toxicity of the photoproducts and the parent drug has been assayed on Daphnia magna and Vibrio fischeri. The results indicate that some photoproducts are more toxic than naproxen.     

PVC塑料浸出液对3种海洋微藻光合作用及生长的影响

海洋微塑料作为一类新型环境污染物已经成为全球性环境问题。运用水样叶绿素荧光仪(Water-PAM)研究了不同浓度软聚氯乙烯(polyvinyl chloride, PVC)和硬PVC浸出液(0、50、100和200 g·L~(-1))胁迫下球等鞭金藻(Isochrysis galbana)、中肋骨条藻(Skeletonema costatum)和小球藻(Chlorella sp.)3种海洋微藻叶绿素荧光特性,包括PSⅡ最大量子产量(F_v/F_m)、PSⅡ实际量子产量(Yield)、光化学淬灭(qP)和PSⅡ最大相对电子传递速率(rETR_(max))的变化,同时检测微藻的生长状况。结果表明,球等鞭金藻(金藻门)和中肋骨条藻(硅藻门)的4项光合作用参数在软PVC浸出液胁迫的96 h内均显著下降,且随软PVC浸出液浓度增加,下降幅度增大,在实验后期(48～96 h)达到最小值,表现为抑制作用。96 h时,球等鞭金藻和中肋骨条藻的细胞密度均在软PVC浸出液200 g·L~(-1)处理组达到最小值,分别占对照组的3.20%和11.90%。硬PVC浸出液胁迫对球等鞭金藻和中肋骨条藻的4项光合作用参数具有显著影响(P<0.05),球等鞭金藻的4项参数均显著高于对照组。中肋骨条藻的相关光合作用参数均显著低于对照组。72 h时球等鞭金藻和中肋骨条藻的细胞密度分别在硬PVC浸出液100 g·L-1和200 g·L~(-1)处理组达到最小值,为对照组的67.90%和82.50%,表现为抑制作用。小球藻(绿藻门)的各光合作用参数和细胞密度在软PVC和硬PVC浸出液胁迫的96 h内未产生显著变化。该研究证实PVC浸出液对微藻光合系统具有干扰作用,对海洋生态系统具有潜在风险。     

Comparison of the insecticidal effects of water extracted and intact aromatic plants onAcanthoscelides obtectus,a bruchid beetle pest of kidney beans

Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.     

生物扰动作用对河口沉积物中荧蒽去除的影响

通过室内微宇宙实验系统研究了天津厚蟹(Helice tientsinensis)和双齿围沙蚕(Perinereis aibuhitensis)生物扰动作用下河口沉积物中荧蒽的去除情况。实验结果显示,天津厚蟹扰动组中荧蒽的去除率显著高于沙蚕扰动组(P=0.05)和对照组(P=0.003),其中对表层(0~2 cm)和中层(3~5 cm)的促进效果最为显著;虽然各实验组表层沉积物中荧蒽的去除率均超过50%,但扰动组的去除更快,在36 d时就达最高去除率68%;双齿围沙蚕扰动组底层沉积物中荧蒽的去除率高于厚蟹扰动组和对照组,但差异不显著。研究表明表层沉积物中的荧蒽易去除,厚蟹生物扰动对荧蒽去除有显著促进作用;在距离表层5cm以下的沉积物中荧蒽的持久性增强,但生物扰动作用可促进其去除。