一株苯系物降解真菌筛选及降解特性

采用逐量分批驯化的方法以污水处理厂污泥作为菌源,苯、甲苯、二甲苯为唯一碳源,驯化、分离、筛选能够有效降解苯系物的真菌,命名为B1。采用单因素以及正交实验方法并对真菌降解环境影响因素及降解效率进行了测定和研究。结果表明:真菌B1对苯系物降解的最佳条件为C:N=5:1,pH5,温度30℃,菌种接种量为5.5ml(50ml培养基)。采用GC对初始液相浓度0~90mg/L范围内的苯系物降解效果进行测定,未发现苯系物对真菌降解活性产生抑制作用。真菌对苯系物的降解效率为:甲苯>苯>二甲苯,最高降解效率分别达到87.39%,85.21%,81.47%。混合物降解效果略高于单一底物的降解效果。     

苯、苯酚、硝基苯对水丝蚓的急性毒性及超氧化物歧化酶活性的影响

苯、苯酚、硝基苯通过工业废水排入到水域当中,是水体常见的污染物,造成水质、植被,以及水生生物一定程度的影响与危害.     

东海带鱼和小型鱼类空间异质性及其空间关系

根据2001年秋季东海区121个调查站位的调查资料,以变异函数为工具,分析带鱼和7种小型鱼类(黄鲫、棘头梅童鱼、鳄齿鱼、六丝钝尾虎鱼、发光鲷、七星底灯鱼和细条天竺鲷)的空间异质性及其空间关系.结果表明,带鱼的变异函数曲线与细条天竺鲷、六丝钝尾虎鱼和发光鲷的曲线极为相似,对不同距离的变异函数值进行相关分析,带鱼与上述3种小型鱼类均达到极显著相关水平(P<0.01).黄鲫和棘头梅童鱼的变异函数表现出纯金块效应,而其它几种鱼都可拟合为球状或指数模型,并且都具有较强的空间自相关特性,其中细条天竺鲷、六丝钝尾虎鱼和发光鲷的变程也都接近或超过带鱼265km的变程,带鱼与这3种小型鱼类之间具有较强的空间追随关系,因此它们是带鱼的主要摄食对象.     

半滑舌鳎病原菌(发光杆菌杀鱼亚种)的分离与鉴定

2006年夏,山东青岛某渔场养殖半滑舌鳎(Cynoglossus semilaevis Gunther)大量死亡。症状主要表现为体表溃烂,鳍基部出血等,解剖可见胆囊发黑,肾脏发黄。从患病半滑舌鳎胆囊分离出优势菌并命名为WY06。人工感染试验证实WY06对半滑舌鳎及模式动物斑马鱼都具有很强的致病性,其半数致死量分别为5.5×103cfu/克鱼(5.2×105cfu/条鱼)和1.9×103cfu/克鱼(8.9×102cfu/条鱼)。该病原菌革兰氏染色阴性,菌体呈杆状。综合该菌在形态、生理生化特征及16S rDNA同源性等方面的结果,确认WY06为美人鱼发光杆菌杀鱼亚种(Photobacterium damselae subsp.piscicida)。该菌对头孢呋肟、菌必治等抗生素敏感。美人鱼发光杆菌杀鱼亚种在美国、日本、欧洲的海水养殖中为常见的病原菌,但作为鱼类病原菌在中国属首次报道。     

关于改革石蜡切片工艺的试验

众所周知,在石蜡切片的制作过程中,历来是用苯类(尤其是二甲苯)作为透明剂和石蜡的有机溶剂。组织块经酒精脱水后,必须再用二甲苯作为中间媒剂将酒精取代出来,然后才能进行透蜡。否则,虽然水分除尽,但组织内部积蓄酒精,石蜡仍难透入。同样,切片染色前和染色后,也需用二甲苯脱蜡和透明。因此,在整个制片过程中,不但要多次用到二甲苯,手续繁琐,而且组织块在二甲苯中浸渍时间较难掌握,久浸会使材料松脆,影响切片质量;时间不足又会影响透蜡效果。另外,苯类是有毒药品,且有致癌作用,对人体极为有害,国外组织学实验室     

操作条件对生物质催化热解产轻质芳烃的影响

以轻质芳烃苯、甲苯、二甲苯以及萘（BTXN）为目的产物,采用双颗粒流化床对松木进行了催化热分解实验。讨论了催化剂CoMo-B加氢催化作用下,静止床高、流化气速、床层压降的相互关系,得到了一个合适的操作条件,为热分解实验提供了必要的基础实验数据。在热分解实验中,调查了操作气速、床层高度以及热解温度对产物收率和分布的影响,得到了中间产物苯、甲苯、二甲苯和萘等轻质芳烃化合物最高收率为6．3％下的最佳操作条件：催化剂为CoMo-B,气速2．0cm／s,床层高度为0．08m,热解温度863K。     

固氮螺菌氢代谢与固氮作用的关系II．苯环类化合物对固氮螺菌吸氢与固氮作用的影响

本文报道了苯环类化台物对固氮螺菌的固氮及吸氢作用的影响。试验结果表明,固氮螺菌能利用苯作为碳素营养,在无其他碳源存在的情况下,生长在含有50和500m肘浓度苯的培养基中,固氮螺菌表现出固氮和吸氢活性。0.5mM的苯酚对固氮螺菌的固氮和吸氢活性略有刺激作用,而I．OmM即表现较强的抑制作用。固氮螺菌完全不能利用对硝基苯酚和2,{一二硝基苯酚作为碳源,即使是0．1mM的浓度对螺菌的固氮和吸氢活性均产生抑制作用。     

苯酚降解菌的分离及培养特性研究

对南充市郊炼油厂活性污泥进行富集,驯化筛选得到2株能以苯酚作为唯一碳源和能源生长的菌株,编号为S1,S2,两菌株可耐10,000mg/L左右的苯酚浓度,实验得出其最佳生长条件为pH7-8,温度25℃-30℃,在适宜条件下,对苯酚有较好的降解能力,而且苯对两菌株的生长表现为抑制作用。     

山楂核干馏油GC-MS主要成分分析及含量测定

本研究目的在于建立气相色谱-质谱联用法(GC-MS)分析山楂核干馏油中挥发油、脂溶性成分以及气相色谱法(GC-FID)同时测定山楂核干馏油中活性成分的定量分析方法。采用GC-MS法对山楂核干馏油化学成分进行分析,共分析出62种化学成分,用峰面积归一化法测定各成分的相对百分含量,含量最高的化合物为醛类,占总量的55.96%。以GC-FID法同时测定山楂核干馏油中的主要成分的含量(糠醛、愈创木酚、2,6-二甲基苯酚、2-甲基苯酚、苯酚、2-甲氧基-4-甲基苯酚、2,6-二甲氧基苯酚、四氯愈创木酚、1,2,3-三甲氧基苯、3,4,5-三甲氧基甲苯),测得加样回收率范围为100.06%~102.44%,RSD范围为2.98%~4.57%。本方法准确、简便、重复性好,为山楂核干馏油制剂的内在质量控制及提升废弃物山楂核循环利用价值提供依据。     

发光的魚

栖息在海洋的鱼类尤其是海底的鱼,常发现有发光的现象。这些鱼能发出红色或紫色的宝石状的光芒。这些鱼在体中含有发光体的机构,通过半透明的肌肉,发出光来。若把这些发光体和体表的发光器制成匀浆来培养不能发光的细菌或喂饲其他不发光的鱼类,我们可在细菌或鱼类的胃中分析出萤光素和萤光酶,在这些鱼类的幽门部中贮藏着萤光素,看来在发光器中还备有萤光酶,从幽门部把少量的萤光素送到发光器,它与萤光酶起作用便射出光芒。看来,发光     

The influence of alarm substance and shoal size on the behaviour of zebra danios, Brachydanio rerio (Cyprinidae)

Timidity, vigilance and response to alarm substance were examined in shoals consisting of one to 12 zebra danios, Brachydanio rerio . Measures of timidity were not clearly related to shoal size. Fish in larger shoals spent more time in central areas of the tank away from cover than fish in smaller shoals. However, fish in small shoals appeared to be as aggressive as those in larger shoals. Vigilance and foraging rates did not appear to be related to shoal size. Per capita foraging rates and shoal size were not correlated. After being frightened by alarm substance, danios in larger shoals did not return to foraging sooner than those in smaller groups. Zebra danios in all shoal sizes responded behaviourally to alarm substance. It appears that the presence of conspecifics is unnecessary for alarm behaviours to occur and that the nature of the behaviours are independent of shoal size.     

Aetiology of skeletal deformities in the Zebra Danio fish (Bruchydanio rerio, Hamilton-Buchanan)

Laboratory bred Zebra Danio ( Brachydanio rerio , Hamilton-Buchanan) tropical fish are prone to skeletal deformities resembling scoliosis and lordosis. This condition appears related to diet and has been studied by breeding from different broods of fish for three generations. Two broods bred using two commercially available tropical flaked foods developed severe spinal curvature three to six weeks post-hatching. A third brood of fish fed exclusively on live food did not develop any deformity. The results demonstrate that a dietary factor is responsible for the deformities and that the Zebra Danio is especially susceptible to this factor as other species breed normally when fed the same commercial diet. Analysis of the diets showed no deficiency in either ascorbic acid (Vitamin C) or tryptophan, deficiency of either being associated with scoliosis and lordosis in fish. The analysis did show, however, a relationship between the lead content of the diet and the incidence of deformities. Lead has previously been implicated in skeletal deformities in second and third generation Brook trout, Salvelinus fontinalis.     

Low-level chemiluminescence from Drosophila melanogaster fed with chemical mutagens polycyclic aromatic hydrocarbon quinones and a carcinogenic bracken fern

The spontaneous photon emission (chemiluminescence) from Drosophila melanogaster fed chemical mutagens, polycyclic aromatic hydrocarbon quinones, and a carcinogenic bracken fern was studied. The fly chemiluminescence was evidently enhanced by mutagen or carcinogen administration and was increased proportionally to the administered amount of tested compound. Strong chemiluminescence was observed especially at the larval stage. Living larvae emitted stronger chemiluminescence than their homogenate. The chemiluminescence from Drosophila melanogaster fed polycyclic aromatic hydrocarbon quinones showed a linear relation with the mutation frequency in the Drosophila wing spot test. The chemiluminescence from flies fed a bracken fern decreased by the addition of free radical scavengers and active oxygen quenchers. The phosphatidylcholine hydroperoxide concentration in the flies was increased proportionally with the chemiluminescence intensity. It seems that the free radical formation is stimulated as shown by the enhanced chemiluminescence in mutagen- or carcinogen-dosed flies, and as a result, lipid peroxide accumulation accompanies mutation in Drosophila melanogaster.     

Spontaneous skeletal deformities in the Zebra Danio (Brachydanio rerio) bred for fish toxicity tests

Zebra Danio ( Brachydanio rerio , Hamilton-Buchanan) tropical fish are easily maintained and bred under laboratory conditions; procedures for maintenance and breeding are described. Intensive inbreeding of this fish gave rise to a high incidence of spontaneous skeletal deformities which appear to reflect a genetic defect rather than an environmental stimulus. This finding casts doubt on the suitability of the Zebra Danio for fish toxicity testing.     

Sub-lethal effect of synthetic pyrethroid pesticide on metabolic enzymes and protein profile of non-target Zebra fish,Danio rerio

Extensive application of pesticide in agricultural field affects the enzymatic activity of non-target animals, including fishes. In this study, the impact of sublethal concentration of fenvalerate on marker enzymes of freshwater Zebra fish was evaluated. Pesticide-induced stress can specifically affect non target fishes, through elevated level of reactive oxygen species which is responsible for biochemical, cell metabolism and physiological activities. The oxidative stress mediated by fenvalerate at sub lethal concentrations after 28 days of exposure of Zebra fish. Following 28 days of exposure of pesticide, catalase, superoxide dismutase, aspartate amino transferases, alanine amino transferase, alkaline phosphatase and acid phosphatase were assessed. Results revealed reduction of superoxide dismutase activity after 28 days of exposure in sub lethal concentration of fenvalerate in liver and gills. In liver, catalase activity was found to be less in fenvalerate exposed fish than control fish. In liver, increase of 75.75% aspartate amino transferase and 38% increase in alanine amino transferase in gills. SGPT activity was relatively higher than SGOT suggests more contribution of phyruvalate than oxaloacetate formation. Fenvalerate induced changes in acid phosphatase and alkaline phosphatase activity in the liver and gills of Zebra fish after four weeks of exposure. Fenvalerate induced expression of various stress proteins in gill, liver, followed by muscle. Some proteins lost its intensity due to fenvalerate toxicity. Result revealed that enzyme assays and SDS-PAGE analysis for protein subunits determination is relevant tool to monitor stress in freshwater ecosystem. The findings suggest that in monitoring fenvalerate toxicity programme, enzyme activities can be potent diagnostic tool for fenvalerate induced toxicity.     

Chemiluminescence microscopy as a tool in biomedical research.

Chemiluminescence has become a standard tool in biomedical research. Chemiluminescent probes are used for immunoassays, nucleic acid identification, reporter gene assays, measuring enzyme activity, and the detection of ions and small molecules such as Ca2+, ATP, NO, O2- and H2O2. Along with the development of new chemiluminescent probes, significant progress has been made in techniques to measure chemiluminescence. Ultra-sensitive photometers or luminometers have become widely available and can be obtained with automatic injectors and microplate readers. In addition, imaging photon detectors have been developed that allow the imaging of chemiluminescence from gels, blots, and microplates. Imaging photon detectors have also been attached to microscopes and allow imaging of chemiluminescent probes and reporter genes in cells and tissues. Specific methods of photon collection, storage, and analysis have been developed for microscopic imaging of chemiluminescence. Two of these methods are discussed in detail. The first is a method of data storage that allows days of continuous imaging without creating oversized files. The second is a method for calibrating photon imaging microscopes using a low-light standard. Such calibration will be helpful for comparing the performance of various photon imaging systems and for comparing data obtained in different laboratories.     

Breeding the convict cichlid (Cichlasoma nigrofasciatum) for use in laboratory fish toxicity tests

A procedure is described for breeding Convict Cichlid ( Cichlasoma nigrofasciatum ) tropical fish under laboratory conditions. Three generations of Convict Cichlids were bred successfully using this procedure and there was no significant incidence of deformities from in–breeding to the F₃ , which contrasts with a high incidence of skeletal deformities observed when Zebra Danio tropical fish were inbred to the F ₃ generation. The Convict Cichlid is a suitable species for laboratory toxicity testing, particularly studies to assess effects on breeding performance.     

Detection of Superoxide Production by Activated Microglia Using a Sensitive and Specific Chemiluminescence Assay and Microglia-Mediated PC12h Cell Death

Abstract: Superoxide production by cultured microglia derived from neonatal rat brains and the cytotoxicity of these cells were evaluated. The chemiluminescence (photon counts) detected in the presence of MCLA, a new chemiluminescence probe, was strongly correlated with the microglial cell count. Chemiluminescence observed in this system was confirmed to originate specifically from superoxide produced by activated microglia. Phorbol myristate acetate-stimulated microglia caused a pronounced reduction of PC12h cell numbers in coculture. The addition of superoxide dismutase with catalase or the addition of deferoxamine mesylate inhibited PC12h cell death, suggesting that active oxygen species derived from superoxide generated by the microglia or iron-oxygen complex formation were responsible for the cytotoxicity. These results imply that activated microglia may participate in the progression of the pathologic process in some neurodegenerative disorders.     

The zebra mussel (<Emphasis Type="Italic">Dreissena polymorpha</Emphasis>) impacts European bitterling (<Emphasis Type="Italic">Rhodeus amarus</Emphasis>) load in a host freshwater mussel (<Emphasis Type="Italic">Unio pictorum</Emphasis>)

The European bitterling, Rhodeus amarus, is a non-indigenous fish species in British fresh waters. It lays its eggs in unionid mussels which themselves are vulnerable to fouling by the non-indigenous zebra mussel, Dreissena polymorpha. Observations from an unmanipulated natural system showed that only 27% of zebra mussel-fouled Unio pictorum hosted bitterling, while 47% of unfouled U. pictorum hosted bitterling. We conducted a field experiment in the River Great Ouse catchment, Cambridgeshire, England in May–June 2007 and 2008 to quantify the impact of zebra mussels on bitterling load in host mussels. Zebra mussel-fouled unionids were significantly less likely to host bitterling than unfouled unionids. The number of unionids hosting bitterling did not differ significantly whether the zebra mussels fouling the unionid were alive or dead. Bitterling appeared to discriminate against zebra mussel-fouled unionids less as the 2007 breeding season advanced, potentially because preferred unfouled unionids had a higher bitterling load, and were therefore relatively lower quality hosts than at the start of the breeding season.