甲基对硫磷降解菌DLL-1的分离、鉴定及降解性研究

从长期施用甲基对硫磷的污染土壤中分离到一株能以甲基对硫磷为唯一碳源生长且能将其完全矿化的细菌 Ｄ Ｌ Ｌ－ １ ,经鉴定,为邻单胞菌（ Ｐｌｅｓｉｏｍｏｎａｓ ｓｐ ．） ．该菌株３ ｈ 内对５０ ｍｇ／ Ｌ甲基对硫磷的降解率为９３ ％ ,２４ｈ 内对５０ ｍｇ／ Ｌ甲基对硫磷的降解率为９５ ％ 以上．在葡萄糖铵盐培养基中, Ｄ Ｌ Ｌ１ 对甲基对硫磷的耐受浓度和降解速度均增大．降解曲线表明延滞期内,菌体依靠上一生长阶段分泌的酶类对甲基对硫磷进行降解,一旦菌体开始生长,则检测不到中间代谢产物对硝基苯酚的存在．生长情况和粗酶液试验均显示 Ｄ Ｌ１ 优良的降解性状     

石墨烯与抑癌基因p53 DNA片段相互作用的分子模拟与光谱学验证

石墨烯(graphene,G)及其衍生物由于具有独特的理化性质,被广泛应用于能源、生物医学等领域,但尚缺乏其对生物体和环境潜在危害的研究。采用分子动力学模拟并结合光谱学方法(紫外可见吸收光谱、紫外变温实验及荧光光谱),分析了石墨烯与抑癌基因p53启动子区DNA片段(p53-DNA)间的相互作用,并探讨了相关作用机制。石墨烯的部分芳香环与p53-DNA碱基的芳香环之间存在π-π堆积作用,两者可以通过嵌插作用进行结合,同时还通过沟槽作用进一步结合。光谱实验进一步证实,在石墨烯作用下,p53-DNA的熔点(Tm)值升高,EB-DNA体系发生静态荧光淬灭,说明石墨烯能与p53-DNA结合;同时,p53-DNA与石墨烯结合后在260 nm处的吸光度升高,说明石墨烯对p53-DNA的双螺旋结构具有一定的破坏作用。上述研究结果从分子水平上分析了石墨烯与p53-DNA间的相互作用机制,有助于进一步阐明石墨烯的毒性作用机理。     

HPLC- RF法快速测定水中苯并(a)芘

利用高效液相色谱仪（ＨＰＬＣ）,将样品中苯并（ａ）芘与其他有机物分离,并同荧光分光光度计（ＲＦ）的微流动池相联,作荧光测定,组成了ＨＰＬＣ－ＲＦ不检测。该方法相地标准差为４．５～７．２％,回收率为８６．５％～９３．５％,检测限为０．０００９μｇ／Ｌ。     

Persistent Organochlorine Residues in Livers of Six Species of Ciconiiformes (Aves) from Spain

p> Liver samples of 42 birds belonging to 6 species of Ciconiiformes (grey heron (n = 17), little egret (n = 12), cattle egret (n = 1), glossy ibis (n = 1), little bittern (n = 1), and white stork (n = 10)), collected from two different zones of Spain (Ebro Delta and Madrid) in 1992–1997, were analyzed for organochlorine pesticides and PCBs. ΣPCBs (sum of concentrations of individual congeners), p,p′-DDE, HCB, γ-HCH, and heptachlor epoxide were the most prevalent residues detected in all samples (occurrence > 95%). There were no statistically significant differences in organochlorine levels between grey herons and little egrets, while levels of ΣPCBs, p,p′-DDE, HCB, γ-HCH, and heptachlor were significantly lower for white storks. These results could be explained by the different habitat of these species, aquatic in the Ebro Delta (grey herons, little egrets) and dry in Madrid (white stork), and their diverse feeding habits.     

Polybrominated diphenyl ethers,polychlorinated dibenzo-dioxins,-furans,and-biphenyls in three species of antarctic penguins

Background, Aims and Scope Fish-eating seabirds are recognized to be at risk of accumulating toxic contaminants due to their high position in the trophic web and to their low ability to metabolize xenobiotic compounds. Penguins are widely distributed in Antarctica and represent an important fraction of the Antarctic biomass. They feed mainly on krill and, depending on krill availability, also on fish. It has been reported that predators may be a sink for volatile and toxic chemicals and this may pose a serious environmental problem. Polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-dioxins (PCDDs),-furans (PCDFs), and-biphenyls (PCBs), including non-ortho congeners, hexachlorobenzene (HCB) and p,p′-DDE, were quantified in three species of Antarctic Pygoscelids in order to evaluate their accumulation patterns. The potential toxicity of twenty-two dioxin-like congeners was assessed and expressed as 2,3,7,8-tetraCDD equivalents (TEQs). Differences between males and females were investigated. Methods Blood samples of the Adélie penguin Pygoscelis adeliae, Chinstrap penguin Pygoscelis antarctica and Gentoo penguin Pygoscelis papua were collected at Admiralty Bay, King George Is (62°10′39″ S, 58°26′46″ W) in February 2004. Halogenated hydrocarbons were identified and quantified using gas chromatography coupled with gas chromatography mass spectrometry analyses. Results are expressed on a wet weight basis. Results and Discussion HCB, p,p′-DDE and ΣPCBs were higher in Adélie penguins (6.7±6.1, 8.2±3.3 and 9.8±3.8 ng/g, respectively) than in Chinstrap and Gentoo penguins, both of which showed values in the same order of magnitude, but approximately 40% lower than Adélie penguins. Hexa-CBs ranged 35–45% of the residue. Low-chlorinated PCBs (nos. 70+76+95+56+60+101) accounted for 40–60% in the three species. PCB101 made up 15% of the residue in Adélie penguins. PBDEs were 291±477, 107±104 and 116±108 pg/g in Adélie, Chinstrap and Gentoo penguins, respectively; the most abundant congeners were BDE47 in Adélie and Chinstrap penguins and BDE17 in Gentoo penguins. PCDDs were 22±32, 6.5±7.4 and 18±23 pg/g in Adélie, Chinstrap and Gentoo penguins, respectively. PCDFs were higher in Adélie penguins and lower in Chinstrap penguins. PCDDs/Fs and PBDEs were higher in males than in females of Gentoo and Chinstrap penguins; differences in concentrations were likely related to the partial detoxification that occurs in females during egg formation. Of the four non-ortho PCBs measured, PCB126 occurred at the highest concentrations and contributed the majority of the non-ortho PCB-TEQ in Gentoo and Chinstrap penguins. The highest TEQs were found in the Gentoo penguin and due mainly to PCDDs and non-ortho PCBs. Conclusions POP concentrations in penguins were lower than those found in seabird species from other areas of the world. Different chemical accumulation patterns were observed in relation to species and sex; the Adélie penguin showed the highest POP levels. Dissimilar ecological or metabolic features may be involved; the diverse timing of reproduction steps can be responsible for those differences; moreover, Adélie penguins feed on krill (a fatty resource) more abundantly than the other two species during the rearing period. Recommendation and Outlook The South Shetland Islands might be subjected to a higher chemical impact with respect to the rest of Antarctica, due to their being near South America. Because penguins are fish-eating birds showing low detoxifying capacities and key-species in Antarctic ecosystems, further studies on their xenobiotic metabolism should be carried out.     

电脑和手机电磁辐射强度测试及防护对策

测试了电脑显示器和手机工作时电磁辐射强度的大小,总结了它们发射电磁波强度大小的规律,并与国家标准进行了比较,针对电磁波的危害提出了一些防护措施和对策。     

Prenatal diagnosis of occipital encephalocele,mega-cisterna magna,mesomelic shortening,and clubfeet associated with pure tetrasomy 20p

We present the first case of a fetus with pure tetrasomy 20p proven by cord-blood sampling at 24 weeks of gestation. This case was diagnosed in utero with multiple congenital anomalies including occipital encephalocele, mega-cisterna magna, mesomelic shortening, and clubfeet. An analysis of GTG-banded chromosomes of 20 metaphase cells was performed. Female karyotype [47,XX, +i(20)(p10)] was revealed in all cells. Pure tetrasomy 20p was confirmed using fluorescent in situ hybridization (FISH) with a telomere probe for chromosome 20p in all seven metaphase cells. The pregnancy was terminated because of associated multiple anomalies and severe oligohydramnios. The postmortem examination confirmed the prenatal diagnosis. Copyright © 2003 John Wiley & Sons, Ltd.     

Prenatal diagnosis of mosaic tetrasomy 5p

We report the prenatal diagnosis of a fetus with tetrasomy 5p mosaicism resulting from a supernumerary isochromosome for the short arm of chromosome 5. The pregnancy was terminated and fetal autopsy revealed minor facial abnormalities (long philtrum, up-slanting palpebral fissures and a broad nasal bridge). Cultures were established from fetal skin, kidney, and pancreas for cytogenetic analysis; the i(5p) was observed only in the skin fibroblasts. To our knowledge, this is the fourth report of mosaic tetrasomy 5p and the first report of prenatal diagnosis of this abnormality. Copyright © 2001 John Wiley & Sons, Ltd.     

Prenatal diagnosis of a mosaic supernumerary marker iso (8p) (tetrasomy 8p): discordance between chorionic villi culture and amniotic fluid karyotypes

We describe the first case of mosaic supernumerary marker iso (8p) displaying a karyotype discordance between chorionic villi (CV) and amniotic fluid (AF) cultures during prenatal cytogenetic diagnosis. In the first trimester, cytogenetic analysis after chorionic villi sampling (CVS) was normal in all metaphases in the short-term cytotrophoblast cell culture, but an undefined supernumerary marker was detected in 60% of mesenchymal cells in the long-term CV culture. Informed of the mosaicism, the couple selected amniotic fluid sampling as a second-trimester confirmatory diagnostic procedure. The supernumerary marker was absent in all of the 25 available AF cells metaphases. The prospective parents received genetic counselling and were informed that the discordance could be interpreted as a placental confined mosaicism or as a true foetal mosaicism with low percentage of affected cells. The couple opted to continue the pregnancy. In the second month of life, the child had abnormal development with severe psychomotor delay and frequent episodes of epilepsy. Postnatal cytogenetic extensive re-evaluation discovered that the previously detected supernumerary marker was indeed an isochromosome (8p) rearrangement present at low frequency in 5% of the blood lymphocytes. Copyright © 2006 John Wiley & Sons, Ltd.