水产养殖用解淀粉芽孢杆菌微胶囊的安全性评价

目的:评价水产养殖用解淀粉芽孢杆菌微胶囊的安全性。方法:参照《GB/T21805-2008化学品藻类生长抑制试验》、《GB/T13266-91水质物质对蚤类(大型蚤)急性毒性测定方法》、《GB/T13267-91水质物质对淡水鱼(斑马鱼)急性毒性测定方法》、《渔药临床试验技术规范》等国家标准及相关法规,观察了解淀粉芽孢杆菌微胶囊对小球藻生长的抑制作用以及对大型蚤、斑马鱼和草鱼的急性毒性,分析了其对养殖水体主要理化因子的影响。结果:解淀粉芽孢杆菌微胶囊在终浓度为0.2～2 000mg/L时对小球藻生长具有促进作用,对小球藻的半数抑制浓度大于2 000mg/L,而且其对大型蚤、斑马鱼和草鱼的半数致死浓度也大于2 000mg/L(或mg/kg体重)。此外,在养殖水体中加入解淀粉芽孢杆菌微胶囊至终浓度为0.2～2 000mg/L后14天内,各浓度组的氨氮含量、硫化物和pH均缓慢下降,仅亚硝酸盐氮含量稍微升高后逐渐缓慢降低,但这些理化因子的变化与解淀粉芽孢杆菌微胶囊的加入量呈负相关关系。结论:解淀粉芽孢杆菌微胶囊实际无毒,对养殖水中氨氮、亚硝酸盐氮、硫化物和pH等理化因子的影响均控制在虾虎鱼仔鱼、黄颡鱼、白斑狗鱼、克氏原螯虾等水产养殖动物的安全浓度范围内,为其在水产养殖中的安全应用提供了重要的科学依据。     

钛对大型溞(Daphnia magna)的毒性研究

钛离子对大型蚤的毒性研究表明,其24、48、96h的半数抑制浓度EC_(50)为6.2,5.1,0.26mg/L.半数致死浓度LC50为6.3,6.0,1.5mg/L。长期实验表明,0.000lmg/L浓度是对大型蚤的生长和繁殖均有影响的最低浓度。本研究为制订饮用水水质卫生标准提供水生生物毒理学方面的资料。     

钛对大型蚤（Daphnia magna）的毒性研究

钛离子对大型蚤的毒性研究表明,其24、48、96h的半数抑制浓度EC50为6．2,5．1,0．26mg/L。半数致死浓度LC50为6．3,6．0,0,1．5mg/L。长期实验表明,0．0001mg/L浓度是对大型蚤的生长和繁殖均有影响的最低浓度。本研究为制订饮用水水质卫生标准提供水生生物毒理学方面的资料。     

复合微生态制剂对水产养殖水体净化作用的研究

目的：考察了复合微生态制剂对水产养殖水体的净化作用。方法：将实验室研制的复合微生态制剂MCB以不同的投放量加入各实验养殖池塘中,根据各池中溶氧、氨氮、亚硝酸盐、硫化物含量随时间的变化情况与空白对照池比较。结果：施放复合微生态制剂的各实验池均比未加复合微生态制剂的对照池溶氧含量明显增加,氨氮、亚硝酸盐、硫化物的含量明显降低;复合微生态制剂MCB的投放周期为10d左右,最佳投放量为9mg／L。结论：每10d左右,施放9mg／L的复合微生态制剂MCB,可对水产养殖水体起到较好的净化作用。     

餐厨垃圾高温菌种对斑马鱼急性毒性与安全评价

目的:研究餐厨垃圾高温菌种对斑马鱼的毒性,为其安全使用提供依据。方法:以具有代表性的水生动物斑马鱼为试材,采用静态法测定餐厨垃圾高温菌种对斑马鱼急性毒性并对其进行安全评价。结果:鱼的半数致死浓度LC50值24、48和96h分别为3400mg/L、3000mg/L和2500mg/L。结论:餐厨垃圾高温菌种对斑马鱼有一定毒性,该研究为餐厨垃圾高温菌种的安全合理使用提供了科学依据。     

不同盐度、pH条件下氨氮对管角螺稚贝毒性影响

在水温28.5℃,采用实验生态学方法研究了不同盐度、pH条件下氨氮对管角螺(Hemifusus tuba)稚贝[壳高(11.3±0.11)mm,n=30]毒性的影响。结果表明,(1)盐度对氨氮的毒性有较大影响,随着盐度的降低,氨氮在水体中的毒性增强;盐度为16、19、23和28,总氨氮对稚贝的96h半数致死浓度(96hLC50)分别为36.5、43.7、52.6和58.8mg/L,安全浓度(SC)为3.7、4.4、5.3和5.9mg/L。(2)氨氮在水体中的毒性随pH的升高而增强,pH为7.6、8.0、8.4和8.8时,总氨氮对稚贝的96hLC50依次为58.3、54.5、50.6和20.2mg/L,对应的SC依次为5.8、5.5、5.1和2.0mg/L。氨氮在pH8.8时对稚贝的96hLC50急剧下降,其毒性是在pH7.6时的2.9倍。     

4种常用水产药物对青虾幼虾的毒性研究

采用静水法研究了4种常用水产药物对青虾幼虾的毒性。结果表明：水温29℃~30℃时,溴氯海因对青虾幼虾24 h、48 h和72 h的LC50分别为19.05 mg/L、11.75 mg/L、11.75 mg/L,安全浓度为1.24 mg/L;聚维酮碘对青虾幼虾的24 h、48 h和72 h的LC50分别为49.27 mg/L、44.61 mg/L、43.68 mg/L,安全浓度为10.52 mg/L;甲醛对青虾幼虾的24 h、48 h和72 h的LC50分别为72.47 mg/L、66.41 mg/L、53.71 mg/L,安全浓度为10.93 mg/L;高锰酸钾对青虾幼虾的24 h、48 h和72 h的半致死浓度（LC50）分别为6.06 mg/L、4.07 mg/L、3.79 mg/L,安全浓度为0.48 mg/L。4种药物对青虾幼虾的毒性依次为高锰酸钾〉溴氯海因〉聚维酮碘〉甲醛。     

7种消毒剂对鲟4种病原菌体外抑菌效果

为了筛选高效的消毒剂用于防治鲟细菌性疾病,采用二倍稀释法测定了7种消毒剂对鲟4种病原菌的最小抑菌浓度(MIC)和最小杀菌质量浓度(MBC)。结果显示,高铁酸钾对鲟4种病原菌抑菌效果最好,MIC为8 mg/L,MBC为8¹6 mg/L,戊二醛、甲醛、苯扎溴铵、过氧化氢及季铵盐络合碘5种消毒剂抑菌效果中等,聚维酮碘对鲟4种病原菌抑菌效果最差,聚维酮碘对鲟4种病原菌的MBC最大值为2048 mg/L。根据上述研究结果,选择抑菌效果好的消毒剂高铁酸钾进一步研究了鲟4种病原菌随时间和高铁酸钾浓度变化的生长趋势,显示消毒液浓度为5 mg/L、9 mg/L的消毒液在短时间能抑制病原菌生长繁殖,病原菌数量同样能在短时间内繁殖恢复到原来的水平,浓度为13 mg/L、17 mg/L的高铁酸钾消毒液能快速杀灭病原菌,病原菌在较长时间维持在较低水平,甚至病原菌全部被杀死。研究对于使用高铁酸钾防治鲟养殖实践中的疾病具有重要的指导意义。     

一株光合细菌的分离鉴定及该菌对氨氮和亚硝态氮的去除作用

【背景】中国是水产养殖大国,氨氮、亚硝态氮是水体中主要的氮源污染物。水体氨氮超标不仅会损伤水生动物的神经系统和肝肾系统,还会导致体表及内脏充血。亚硝态氮过高会阻碍血液运载氧气能力,导致鱼虾缺氧、免疫力下降,从而引发肠炎、烂鳃,甚至窒息死亡。部分光合细菌有去除水体氨氮、亚硝态氮的能力,且对环境友好无二次污染。【目的】从广东养殖水体分离、纯化、筛选出生物活性好的光合细菌(编号SP3)进行种属鉴定,优化培养条件,检测其去除水体氨氮和亚硝态氮的能力,为养殖水体去除氨氮和亚硝态氮提供目标菌株。【方法】用双层平板法从混合菌液中分离得到光合细菌,通过革兰氏染色、碳源利用试验、对无机电子供体的利用试验以及16SrRNA基因序列分析对目标菌株进行种属鉴定;测定菌株SP3在不同pH、不同浓度NaCl条件下的OD600,优化培养条件;通过测定7d内SP3菌株在不同浓度氨氮(氯化铵配制)和亚硝态氮(亚硝酸钠配制)中OD600的变化趋势,确定该菌株对不同氮源的利用情况;用纳氏比色法、分光光度法测定SP3菌株降解水体氨氮和亚硝态氮的能力。Genome walking扩增获得亚硝酸盐还原酶基因(nirS),通过荧光定量PCR研究nirS在氨氮、亚硝态氮去除过程中的表达动态。【结果】筛选出的菌株SP3为革兰氏阴性菌,短杆状;能以醋酸盐、丙酮酸盐、丙酸盐、丁酸盐、乳酸盐、富马酸盐、琥珀酸盐、苹果酸、果糖、葡萄糖作为碳源,不能以乙醇和丙酮作为碳源;能利用硫化钠、硫代硫酸钠、亚硫酸钠作为无机电子供体; 16SrRNA基因序列分析表明其与沙氏外硫红螺菌(Ectothiorhodospira shaposhnikovii)序列相似度为99%;菌株SP3适宜pH为6.0-8.5,适宜盐度为0-3%;菌株SP3以铵盐作为氮源时生长状态明显优于亚硝酸盐;以初始菌液浓度8.6×109CFU/mL、起始氨氮量84.15±0.58 mg/L的条件培养7 d,水体氨氮累计去除量为79.45±0.29 mg/L,氨氮累计去除率达到94.42%;在同样菌浓度和2mg/L亚硝酸钠的条件下培养5d,水体亚硝态氮含量低于检测限0.003mg/L。在菌株SP3去除氨氮、亚硝态氮过程中nirS相对表达量上调。【结论】菌株SP3为沙氏外硫红螺菌(E.shaposhnikovii),能有效去除水中氨氮和亚硝态氮,具有净化水质作用,在水产养殖和污水处理中有广阔应用前景。     

亚硝酸盐氮对凡纳滨对虾毒性和抗病相关因子影响

用常规生物毒性实验方法,在不同盐度下进行亚硝酸盐氮对凡纳滨对虾的急性毒性实验;并加亚硝酸盐氮于凡纳滨对虾的养殖环境中,检测与抗病力相关因子的变化。研究亚硝酸盐氮对凡纳滨对虾的毒性和抗病力相关因子的影响。结果表明:盐度对亚硝酸盐氮的毒性有较大影响。盐度为31时,24hLC50、48hLC50、72hLC50和96hLC50分别为314.9mg/L1、75.3mg/L1、00.2mg/L和89.0mg/L;盐度为17时,分别为132.3mg/L、65.6mg/L、51.3mg/L和39.5mg/L。盐度31实验组的亚硝酸盐氮半致死浓度均显著(P<0.05)高于盐度17实验组。在低盐度条件下亚硝酸盐氮的毒性较强。亚硝酸盐氮对凡纳滨对虾抗病力相关因子有显著的影响。亚硝酸盐氮浓度为4.0mg/L和8.0mg/L时,其血细胞数、超氧化物歧化酶(SOD)活力、酚氧化酶(PO)活力、抗菌活力(Ua)、溶菌活力(UL)和血清蛋白含量均显著(P<0.05)低于对照组;不吸污组抗病力相关因子活性均显著(P<0.05)低于吸污组。低浓度的亚硝酸盐氮可降低凡纳滨对虾抗病能力,亚硝酸盐氮浓度越高,其抗病能力越弱。     

双氟沙星在人工感染嗜水气单胞菌的异育银鲫体内的药代动力学

为了阐明双氟沙星在健康与处于患病状态下的异育银鲫(Carassius aurutus gibelio)体内的药代动力学特征差异,为双氟沙星的正确合理用药提供参考,本研究通过人工创伤感染的方式采用最佳浓度的嗜水气单胞菌(Aeromonas hydrophila)感染异育银鲫,在此基础上进一步以双氟沙星在健康异育银鲫体内的药代动力学特征为对照,采用反相高效液相色谱法测定双氟沙星在感染嗜水气单胞菌的异育银鲫体内的药代动力学特征。实验结果表明,以鱼体重的20 mg/kg口灌给药后,双氟沙星在人工感染嗜水气单胞菌的异育银鲫与健康异育银鲫体内的总药时曲线均符合一级吸收开放性二室模型,其药动学方程分别为C=6.227e^-0.109t-8.074e^-2.752t+1.847e^-0.006t和C=110.295e^-0.331t+1.533e^-0.01t-111.828e^-0.412t,但与双氟沙星在健康异育银鲫体内的药代动力学参数相比,双氟沙星在人工感染嗜水气单胞菌的异育银鲫体内的吸收、分布、消除速度减慢,其在人工感染嗜水气单胞菌的异育银鲫体内的分 布半衰期、消除半衰期、吸收速率常数、曲线下面积分别增加了4.25 h、36.17 h、2.34/h和74.52 mg·h/L,达峰时间延长了5.75 h,峰浓度降低了61.16%,且未出现重吸收现象。本研究证实嗜水气单胞菌感染能够导致异育银鲫肝肾功能损伤,因而双氟沙星在人工感染嗜水气单胞菌的异育银鲫体内的吸收、分布、代谢和消除均会减慢。     

Biohydrogen production by immobilized Chlorella sp. using cycles of oxygenic photosynthesis and anaerobiosis

Hydrogen production was studied using immobilized green alga Chlorella sp. through a two-stage cyclic process where immobilized cells were first incubated in oxygenic photosynthesis followed by anaerobic incubation for H₂ production in the absence of sulfur. Chlorella sp. used in this study was capable of generating H₂ under immobilized state in agar. The externally added glucose enhanced H₂ production rates and total produced volume while shortened the lag time required for cell adaptation prior to H₂ evolution. The rate of hydrogen evolution was increased as temperature increased, and the maximum evolution rate under 30 mM glucose was 183 mL/h/L and 238 mL/h/L at 37 °C and 40 °C, respectively. In order to continue repeated cycles of H₂ production, at least two days of photosynthesis stage should be allowed for cells to recover H₂ production potential and cell viability before returning to H₂ production stage again.     

Biochemical degradation pathway of reactive blue 13 by Candida rugopelliculosa HXL-2

A strain HXL-2 from a lab-scale sequence batch reactor (SBR) was identified as Candida rugopelliculosa based on its physiological, biochemical characteristics, and 26S rDNA D1/D2 gene phylogenetic analysis. About 90% of the 50 mg/L Reactive blue 13(RB13) was degraded in 48 h after inoculation with strain HXL-2. The optimum efficiency of pH on decolorization was obtained at pH 5.The optimum efficiency temperature of C. rugopelliculosa HXL-2 decolorization RB13 was obtained at 28 °C. The color removal efficiency was obtained at 80.3% when the feed concentration reached 2000 mg/L. We first detected naphthalene-like compound is produced as degradation intermediate after the cleavage of RB13 azo bond, detected 1-chloro-3-aniline- 2,4,6-triazine. We proposed degradation pathway of Reactive blue 13 by Candida sp and proved RB13 degradation pathway by Candida sp. has some difference from RB13 degradation pathway by Pseudomonas sp.     

异育银鲫GABAB受体1亚基cDNA部分序列的克隆及表达分析

为了确定γ-氨基丁酸B受体（gamma-aminobutyric acid B receptor,GABA_BR）基因在异育银鲫（Carassius auratus gibelio）不同组织中的表达,本实验分别对异育银鲫不同组织中GABA_BR1基因进行RT-PCR扩增,并进行了克隆和测序,在与GenBank基因库中已知GABA_BR1序列进行同源性比对的基础上采用邻接法构建系统发育树,并进一步分析其在异育银鲫不同组织内的表达水平。经克隆获得异育银鲫GABA_BR1基因CDS区序列383 bp,编码127个氨基酸。荧光定量PCR结果显示,GABA_BR1基因在异育银鲫脑、肝、肾、心、肠、鳔、鳃、肌、尾鳍、脾、卵巢、精巢组织中均有表达,且在不同组织中的表达水平由高到低依次是：脑>尾鳍>精巢>心、肠、鳔>卵巢、脾、鳃、肌>肝、肾。本研究证实了GABA_BR1基因在异育银鲫各组织中表达的广泛性,且有明显的组织特异性。     

Recent population expansions of non-native ascidians in The Netherlands

Over the last 50 yrs seven non-native ascidians have settled in The Netherlands, concentrated in the two periods 1974-1977 and 1991-2004 (i.e., Styela clava, Aplidium glabrum, Diplosoma listerianum, Didemnum sp., Botrylloides violaceus, Molgula complanata and Perophora japonica). The year of the introduction of B. violaceus remains a matter of dispute because many of the Botrylloides specimens that are recorded in western Europe, have been identified as the closely resembling species B. leachi. Only Didemnum sp. has become a true invasive species and has become a threat to native ecosystems, especially in the province of Zeeland, by its ability to overgrow virtually all hard substrata present. This includes rocks, stones, sand, algae and almost all sessile marine animals. The sudden population expansion of the didemnid from 1996 onward, coincided with the cold winter of 1995-1996, which caused decreased population sizes of many marine animals. The resulting increase in the availability of suitable substrates for settlement and the strong decrease of grazing sea urchins, may have triggered the population expansion. Studying its population dynamics, the optimal growing temperature for Didemnum sp. appears to be 14-18 °C. Virtually all colonies die when the water temperature gets colder than 5 °C. Colonies growing on live marine animals seem to be more resistant to the cold, than those growing on rocks, stones and plants. Two potential predators of the didemnid have also been recorded in Dutch waters: the gastropods Trivia arctica and Lamellaria sp.     

Postingestive sorting of living and heat-killed Chlorella within the sea scallop, Placopecten magellanicus (Gmelin)

Suspension-feeding bivalves may enhance the energy value of their food supply by sorting particles both before and after ingestion. Previous research has indicated that the sea scallop (Placopecten magellanicus (Gmelin) (Mollusca: Bivalvia)) is capable of sorting particles within the gut both on the basis of physical properties (particle size and density) as well as chemical properties. In this study, the ability of the sea scallop to sort living from dead material solely on the basis of chemical properties was tested. The microalga Chlorella (Chlorophyta: Chlorophyceae) was chosen as the test particle because its thick cell wall remains physically intact following heat treatment, while its carbon, nitrogen, and chlorophyll a content declines. Scallops were fed a mixture of radiolabelled live and heat-killed Chlorella. We demonstrate that P. magellanicus can distinguish between living and dead algae, retaining live Chlorella cells longer than heat-killed cells. This ability to detect the subtle chemical differences between living algal material and detrital material would enhance the digestive efficiency of this species by reducing the amount of energy expended, digesting poor-quality materials. This paper presents the first study of the ability of a bivalve to distinguish between two physically identical but nutritionally different forms of the same species of microalgae.     

The Genera Haplocytheridea Stephenson, 1936 and Cytheridea Bosquet, 1852 (Subphylum Crustacea, Class Ostracoda) from the Early Miocene Pirabas Formation, Brazil

The genera Haplocytheridea and Cytheridea have Tethyan origins and a wide paleobiogeographic and stratigraphic distribution, ranging from the Cretaceous to Recent. Both of them have been recorded in northern South America, but only Cytheridea has been found in the northern Cretaceous basins of Brazil. The genus Haplocytheridea is recorded, for the first time, in the Early Miocene deposits of the Pirabas Formation of northern Brazil, from a 20 m-thick succession of carbonate and argillaceous rocks deposited in lagoonal and restricted platform environments. Among the ten Haplocytheridea species identified, four are new: H. variopunctata n. sp., H. sandbergi n. sp., H. pirabasensis n. sp. and H. sinuosa n. sp. In addition, three new species of Cytheridea are also described: C. coimbrai n. sp., C. pirabasensis n. sp. and C. purperae n. sp. The highest frequencies and abundances of both genera, in the studied section, are thought to be associated with nearshore to brackish water settings.     

磷浓度对小环藻、大型溞和金鱼藻三者相互作用的影响

为了解磷浓度对水生植被恢复和生物操纵效果的影响, 分别用小环藻(Cyclotella sp.)、大型溞(Daphnia magna)和金鱼藻(Ceratophyllum demersum)代表浮游植物、浮游动物和大型沉水植物建立水生微宇宙模型, 在25℃、2600 lx光强和11 mg/L氮浓度条件下, 分别研究小环藻与大型溞、小环藻与金鱼藻、小环藻-大型溞-金鱼藻共培养时4种磷浓度(0.05、0.1、0.5和2 mg/L)下小环藻、大型溞、金鱼藻的增长率以及培养液中氮磷去除率的变化。结果表明: 小环藻与大型溞、小环藻与金鱼藻两两共培养时, 磷浓度为0.05-2 mg/L时, 金鱼藻和大型溞均生长良好, 小环藻受到明显抑制, 其密度保持较小幅度的正增长。在小环藻-大型溞-金鱼藻三者共培养时, 在0.05-2 mg/L的磷浓度范围内大型溞和金鱼藻生长良好, 与两两共培养相比, 小环藻则受到了更大程度的抑制, 在磷浓度为0.05-0.1 mg/L时藻密度呈现负增长. 这说明在水生态系统中, 大型浮游动物和沉水植物对浮游藻类的联合控制效果远好于各自单独的控制效果, 该控制效果随磷浓度的提高而减弱, 以0.1 mg/L的磷浓度为最佳。在实验结束后测定氮磷去除率发现, 在最低磷浓度(0.05 mg/L),即磷限制时, 水中磷去除率最高, 在最高磷浓度(2 mg/L), 即氮限制时, 水中氮去除率最高。