海洋维生素B12供求变化及其生态意义

维生素B_(12)是一类积极参与生理活动的物质,在细胞营养和机体代谢中起着重要作用。人们长期缺乏B_(12),会导致多种疾病。 B_(12)作为海洋中的一种生态因子,活跃在海洋生物生产力和食物链中,影响着海洋生物的盛衰和种群的连续。研究海洋中的B_(12)也能     

中国对虾营养研究——B族维生素（B1,B6）对对虾蛋白酶和淀粉酶活力的影响

本文主要研究饵料中B族维生素Vit.B_1和Vit.B_6对对虾肝胰脏淀粉水解酶和类胰蛋白水解酶活性的影响,从而阐述Vit.B_l和vit.B_6在对虾体内碳水化合物代谢和蛋白质代谢中所起的重要作用。实验结果表明,添加Vit.B_1 6mg、Vit.B_6 6mg╱100g饵组对虾肝胰脏淀粉酶比活性最高,是对照组的1.7倍,是组Ⅲ的3.8倍。类胰蛋白水解酶的比活性随饵料中Vit.B_1和Vit.B_6含量的递增而升高。当实验全部改用对照饵喂养各组对虾时,其上述两种消化酶的比活性又分别趋向一致。     

苏北滨海湿地互花米草潮滩CO2,CH4和N2O通量的日变化规律

The invasions of the alien species such as Spartina alterniflora along the northern Jiangsu coastlines have posed a threat to biodiversity and the ecosystem function.Yet,limited attention has been given to their potential influence on greenhouse gas(GHG) emissions,including the diurnal variations of GHG fluxes that are fundamental in estimating the carbon and nitrogen budget.In this study,we examined the diurnal variation in fluxes of carbon dioxide(CO_2),methane(CH_4),and nitrous oxide(N2O) from a S.alterniflora intertidal flat in June,October,and December of 2013 and April of 2014 representing the summer,autumn,winter,and spring seasons,respectively.We found that the average CH_4 fluxes on the diurnal scale were positive during the growing season while negative otherwise.The tidal flat of S.alterniflora acted as a source of CH_4 in summer(June) and a combination of source and sink in other seasons.We observed higher diurnal variations in the CO_2 and N_2O fluxes during the growing season(1 536.5 mg CO_2 m~(–2) h~(–1) and 25.6 μg N_2O m~(–2) h~(–1)) compared with those measured in the non-growing season(379.1 mg CO_2 m~(–2) h~(–1) and 16.5 μg N_2O m~(–2) h~(–1)).The mean fluxes of CH_4 were higher at night than that in the daytime during all the seasons but October.The diurnal variation in the fluxes of CO_2 in June and N_2O in December fluctuated more than that in October and April.However,two peak curves in October and April were observed for the diurnal changes in CO_2 and N_2O fluxes(prominent peaks were found in the morning of October and in the afternoon of April,respectively).The highest diurnal variation in the N_2O fluxes took place at 15:00(86.4 μg N_2O m~(–2) h~(–1)) in June with an unimodal distribution.Water logging in October increased the emission of CO_2(especially at nighttime),yet decreased N_2O and CH_4 emissions to a different degree on the daily scale because of the restrained diffusion rates of the gases.The seasonal and diurnal variations of CH_4 and CO_2 fluxes did not correlate to the air and soil temperatures,whereas the seasonal and diurnal variation of the fluxes of N_2O in June exhibited a significant correlation with air temperature.When N_2O and CH_4 fluxes were converted to CO_2-e equivalents,the emissions of N_2O had a remarkable potential to impact the global warming.The mean daily flux(MF) and total daily flux(TDF) were higher in the growing season,nevertheless,the MF and TDF of CO_2 were higher in October and those of CH_4 and N_2O were higher in June.In spite of the difference in the optimal sampling times throughout the observation period,our results obtained have implications for sampling and scaling strategies in estimating the GHG fluxes in coastal saline wetlands.     

毛蚶血清凝集素的凝集活性

以毛蚶为实验材料,对其血清中的凝集素进行研究.毛蚶血清凝集素对人的A,B,O血型红细胞、鸡和小鼠的红细胞均有凝集作用,凝集效价分别为256,256,8,16,64,同时它还能对白色念珠菌、啤酒酵母、溶藻胶弧菌等微生物具有凝集作用.毛蚶血清凝集素具有一定的pH值稳定性和热稳定性.在选用的12种单糖和寡糖中,L-鼠李糖、L-树胶醛糖、麦芽糖、D-半乳糖、蔗糖对毛蚶血清的凝集活性有明显的抑制作用.用弧菌对毛蚶进行免疫刺激时,其血清对鸡红细胞的凝集效价明显增加.     

菲和Cd2+单一及复合污染对毛蚶氧化胁迫效应的比较

采用半静态染毒实验研究了菲和Cd²⁺单一及复合污染下胁迫9 d和清水释放2 d过程中毛蚶体内活性氧(ROS)、谷胱甘肽(GSH)含量和谷胱甘肽硫转移酶(GST)活性的变化。结果表明,菲和Cd²⁺单独胁迫能诱导毛蚶体内ROS含量的增加及GSH含量、GST活性的降低,且随染毒浓度的增加,对各指标影响愈明显,存在剂量-效应关系。毛蚶体内GSH和GST的变化趋势具有一致性。菲和Cd²⁺复合污染对毛蚶体内的氧化胁迫效应整体大于二者单独污染。在清水释放阶段,单一及复合污染胁迫组各指标均能恢复至对照组水平。表明毛蚶体内抗氧化系统适合作为监测海洋多环芳烃和重金属复合污染的生物标志物。     

BaFe0.4 Sn0.6 O3 /BaBiO3负温度系数复合热敏陶瓷阻抗分析

以BaBiO₃为导电相,BaFe_0.4Sn_0.6O₃为高阻相,采用固态反应法制备了不同BaBiO₃含量的BaFe_0.4Sn_0.6O₃/BaBiO₃负温度系数(NTC)热敏复合陶瓷.为获得在渗流阈值(即BaBiO₃含量为12 mol%)前后复合陶瓷的内部导电机理,对复合陶瓷进行了阻抗分析.分     

饲料中维生素B6对皱纹盘鲍幼鲍蛋白质代谢的影响

以皱纹盘鲍(Haliotis discus hannaiIno)幼鲍为研究对象,探讨维生素B6对其蛋白质代谢的影响。设计了3种维生素B6不同含量(0,40,4 000 mg/kg)的半精制饲料,在循环水养殖系统中养殖幼鲍240 d。结果表明,皱纹盘鲍内脏团和肌肉中磷酸吡哆醛(PLP)的含量随饲料中维生素B6的添加而显著升高(P<0.05)。饲料中不同维生素B6水平对肌肉组织中蛋白含量没有显著影响(P>0.05),而显著升高内脏团中蛋白质的含量(P<0.05)。内脏团和肌肉中的谷丙转氨酶(ALT)和谷草转氨酶(AST)活力随着饲料中维生素B6添加量的升高而显著增强,分别在维生素B6的添加量为4 000 mg/kg时取得最大值(P<0.05)。内脏团中所检测的各种氨基酸的含量与饲料中维生素B6添加量没有显著影响(P>0.05)。然而,肌肉中的天冬氨酸(Asp)、苏氨酸(Thr)、丝氨酸(Ser)、牛磺酸(Tau)的含量随着饲料中维生素B6添加量的升高而显著增加,并且分别在维生素B6添加量为4 000 mg/kg时取得最大值(P<0.05)。肌肉中甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、蛋氨酸(Met)的含量在两个维生素B6添加组(40 mg/kg和4 000 mg/kg)之间没有显著差异(P>0.05),但均显著高于维生素B6缺乏组(0 mg/kg)的值(P<0.05)。     

海洋污染对毛蚶超氧化物歧化酶影响的研究

采用体内、体外染毒实验,研究了海洋中常见污染物0＃柴油、二甲苯以及重金属镉离子(Cd2+)对毛蚶(Scapharca subcrenata)肌肉超氧化物歧化酶(SOD)活性的影响.结果表明,在实验剂量范围内,3种污染物对毛蚶肌肉中SOD均表现出不同程度诱导作用;0＃柴油和二甲苯体内、体外染毒对毛蚶SOD活性影响规律基本一致,这两种污染物对毛蚶SOD活性变化的剂量-效应曲线均为抛物线型;Cd2+在体内、体外染毒对毛蚶肌肉SOD活性诱导曲线均不呈抛物线型,低浓度Cd2+对毛蚶SOD活性表现为显著诱导,随后曲线迅速下降,表明毛蚶对Cd2+污染反应十分敏感,也表明Cd2+对毛蚶毒性作用较强,3种毒物对毛蚶的毒性强弱次序为,Cd2+,0＃柴油、二甲苯.     

海水中的18O/16O比值及其应用

氧是地球上最丰富的元素,自然界中的氧元素实际上是多个稳定同位素(~(16)O,~(17)O,~(18)O)的混合物,它们的丰度相差很大,~(18)O占0.1995％,~(16)O占99.763％,~(17)O只占0.0375％。由于氧同位素丰度大,质量差也大,因此,可以测定~(18)O/~(16)O的比值,并且通过比值的变化了解     

冲绳海槽Z14-6孔氧同位素地层学研究

本文利用取自冲绳海槽中部的Z_(14-6)。孔岩心中所含两种浮游有孔虫进行了氧同位素地层学研究。结果表明,该孔氧同位素记录可划分为6期,其中第5期又可分为5个亚期。与V_(28-238),V_(19-29)孔的氧同位素曲线对比发现,Z_(14-6)孔的氧同位素记录与大洋氧同位素记录完全一致,历时约12.8万年。同时,Z_(14-6)孔氧同位素记录指示出该区12万年来曾存在三个温暖时期。     

Distributions of dissolved vitamin B12 and Co in coastal and open-ocean environments

Distributions of dissolved vitamin B₁₂ and total dissolved Co were measured to gain an understanding of the cycling of these interdependent micronutrients in six marine settings including; an upwelling location, a semi-enclosed bay, two urban coastal systems, and two open ocean locations. Along the coast of Baja California, Mexico, concentrations of B₁₂ and dissolved Co varied from 0.2 to 11 pM and 180 to 990 pM, respectively. At a nearby upwelling station, vitamin B₁₂ and Co concentrations ranged from 0.3 to 7.0 pM and 22 to 145 pM, and concentrations did not correlate with upwelling intensity. Concentrations of B₁₂ were highest within Todos Santos Bay, a semi-enclosed bay off the coast of Baja California, Mexico, during a dinoflagellate bloom, ranging from 2 to 61 pM, while Co concentrations varied between 61 and 194 pM. In the anthropogenically impacted Long Island Sound, NY, U.S.A., B₁₂ levels were between 0.1 and 23 pM and Co concentrations varied from 60 to 1900 pM. However, anthropogenic inputs were not evident in B₁₂ levels in the San Pedro Basin, located outside Los Angeles, Ca, U.S.A., where concentrations of B₁₂ were 0.2–1.8 pM, approximating observed open ocean B₁₂ concentrations. In the Southern Ocean and North Atlantic Ocean, B₁₂ levels were 0.4–4 pM and 0.2–2 pM, respectively. Total Co concentrations in the Southern Ocean and North Atlantic tended to be low; measuring 26–59 pM and 15–80 pM, respectively. These low Co concentrations may limit B₁₂ synthesis and its availability to B₁₂-requiring phytoplankton because the total dissolved Co pool is not necessarily entirely bioavailable.     

Distribution and seasonal variation of vitamin B12, thiamine and biotin in the sea

The distributions and seasonal variations of vitamin B₁₂, thiamine and biotin were investigated in waters of the North Pacific Ocean, the East China Sea, and the bays and inlets along the Pacific coast of Japan, by use of microbiological assay methods. A marine diatom Cyclotella nana clone 3H for vitamin B₁₂, and marine yeast Cryptococcus albidus for thiamine, and a marine bacterium Achromobacter sp. strain yH-51 for biotin were used as assay organisms. In the surface water of Sagami Bay, monthly changes in the amounts of the three dissolved vitamins followed closely that of chlorophyll a, being highest in July and lowest during late autumn and winter. The geographical and vertical distributions of thiamine and biotin in the sea generally showed similar patterns to that of chlorophyll a, whereas vitamin B₁₂ did not always follow the trend. Amounts of particulate thiamine and biotin corresponded to about 1 % of that of the dissolved form in the surface water of the North Pacific Ocean. In the coastal waters, however, they were at times found to be 144.0 % and 53.9 % respectively.     

Nd3+ :Gd3 Sc2 Al3 O12 晶场能级及拟合

Nd³⁺ :GSAG是性能优良的942 nm激光晶体.用提拉法成功生长Nd³⁺ :GSAG单晶,研究其室温透射光谱,辨认位置高达29967 cm^-1的68个Nd³⁺晶场能级.对这些能级拟合了自由离子及晶场Hamilton参量,拟合标准偏差为16.7 cm^-1,表明实验与计算能级符合很好.获得的Hamilton参量可用于计算Nd³⁺ :GSAG中Nd³⁺的     

深圳湾、大鹏湾海水和底泥中维生素B_1,B_(12)测定结果及初 步分析

于1989－1991年对深圳湾、大鹏湾海水及底记的维生素B1和B12含量进行了测定。结果表明，两湾海水中维生素B1和B12含量绝大多数在10ng／L以下；在底泥中的含量最高也仅36×10－9，不会诱导赤潮发生。     

铁、氮、磷、维生素B1和B12对海洋原甲藻的生长效应

４因子，２水平（铁为４水平）正交试验表明：络合铁和硝态氮对海洋原甲藻的生长有极显著的促进作用（Ｐ＜０．０１），维生不Ｂ１，Ｂ１２混合液有显著促进作用（Ｐ＜０．０５）。络合铁和硝态氮为大鹏湾浮游植物生长的营养限制因了。而磷酸盐的作用不显著。     

X60钢在CO2饱和盐水中缓蚀作用的研究

本文采用动电位极化、线性极化、电偶电流和高压釜挂片失重等法,研究了含氮、硫有机缓蚀剂和/或Me~(2+)对X60钢在CO_2饱和的盐水溶液中的缓蚀作用。结果表明,含氮、硫的有机缓蚀剂在缓蚀过程中,开始是以抑制阳极过程为主,随后是以抑制阴极过程为主的混合型缓蚀剂。如与Me~(2+)复配使用,能明显地提高缓蚀效能。     

PALEOMAGNETIC STUDY OF Dc1 AND Dc2 CORES IN THE EAST CHINA SEA

We got two cores from 10 miles east of Zhoushan islands about 29 m in water depth in 1979 and 1980.Dc1 core, 26 m long, can be divided into two layers; 0-19.4 m, brown-yellow, silty-clay, rich in foraminifera, 19.3-26 m, grey silt. DC1 core, 91 m long, 7 miles south of DC1 core. The colour for 0-16.6 m is the same as for 0-19.4 m of Dc2 core, brown silty-clay, rich in foraminifera too. The results of paleomagnetic measurements show: there are 464 specimens in DC1 and Dc2 cores altogether; AF demagnetization often shows that 95 % of all the specimens belong to normal polarity epoch, and the others are reversal ones.We consider that more stranger intensity may represent the warming period and transgression period, and vice versa. At least DC, and Dc2 cores provide such an evidence for this. It is obvious that glacial period should be low peak period of intensity, and interglacial period should be its high peak period.