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91.
In this study, several methods were compared for the efficiency to concentrate venom from the tentacles of jellyfish Rhopilema esculentum Kishinouye. The results show that the methods using either freezing-dry or gel absorption to remove water to concentrate venom are not applicable due to the low concentration of the compounds dissolved. Although the recovery efficiency and the total venom obtained using the dialysis dehydration method are high, some proteins can be lost during the concentrating process. Comparing to the lyophilization method, ultrafiltration is a simple way to concentrate the compounds at high percentage but the hemolytic activities of the proteins obtained by ultrafiltration appear to be lower. Our results suggest that overall lyophilization is the best and recommended method to concentrate venom from the tentacles of jellyfish. It shows not only the high recovery efficiency for the venoms but high hemolytic activities as well. 相似文献
92.
南沙群岛海域沉积物-海水界面间营养物质的扩散通量 总被引:25,自引:1,他引:25
主要研究了南沙群岛海域泻湖及礁外沉积物间隙水生态系中的营养 组份 NO3-N, NO2-N, NH4-N, PO4-P, SiO3-Si及其在沉积物一海水界面间扩散转 移通量,结果表明:(1)该海域间隙水中营养组份的浓度较高,∑N/P礁外间 隙水高于泻湖间隙水,相对而言,泻湖间隙水中缺氮,礁外间隙水中缺磷,礁外 间隙水中营养组份的垂直分布各异。(2)该海域沉积物活性明显高于东中国 海,沉积物中大量营养组份向上覆海水扩散转移,H4SiO4是礁外界面扩散是最 大的组份,而在泻湖中NO3-或NH4+是最大扩散量的组份,礁外界面H4SiO4, NO3-扩散大于泻湖,这些扩散转移特征由组份本身的性质与环境特性决定; (3)该海域水温高是造成间隙水中营养组份大量产出并向上覆海水扩散转移 的主要原因,温度高,沉积物释放出营养组份的表现活化能降低,沉积物的活 性增强,从而释放扩散出大量的营养组份。 相似文献
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99-4航次对南沙珊瑚礁区进行了考察,利用现场投放沉积物捕捉器采集沉降颗粒物样品,从生物与非生物体系两个侧面对南沙珊瑚礁生态系的碳循环作了深入的研究。结果表明,无机碳是珊瑚礁生态系中各种样品碳的主要存在形式,总碳的收支主要受到溶解平衡与钙化作用的控制。有机碳在珊瑚礁泻湖中具有很高的循环效率,泻湖中垂直转移的颗粒有机碳有93%以上在进入沉积物之前被释放,其中生物碎屑的颗粒有机碳释放率约为99%。珊瑚礁植物尤其是与珊瑚共生的虫黄藻等的光合作用以及珊瑚礁的拟流网模型、休渔模型分别代表了构成珊瑚礁有机碳循环的两个主要方面,即:高效循环和稳定补充。因而珊瑚礁保护应当重点保护珊瑚礁水环境和生物多样性资源。 相似文献
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采用颗粒流程序 PFC构建了试件直接拉伸模型,模拟了含2条断续裂隙试件的直接拉伸试验,通过完整试件的模拟结果与室内试验结果的对比,验证了细观参数的准确性和可靠性,同时分析了裂隙倾角和岩桥倾角对抗拉强度和裂纹扩展的影响。研究表明:在直接拉伸情况下,含2条断续裂隙试件以萌生次生倾斜反翼裂纹为主,少量次生共面裂纹和翼裂纹;岩桥倾角和裂隙倾角均较小时,次生共面裂纹与原始裂隙之间发生搭接、贯通,随着岩桥倾角和裂隙倾角的加大,次生倾斜反翼裂纹扩展使试件 断裂;裂纹扩展的方向与最大拉应力的方向基本保持垂直;岩桥倾角对于试件的抗拉强度和起裂应力影响不大;裂隙倾角对于试件抗拉强度和起裂应力影响明显,裂隙倾角越大,试件抗拉强度和起裂应力越大。 相似文献
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99.
The pigments in Laminariajaponica was extracted with six organic solvents and analyzed in spectroscopy analysis. The extractions conditions were screened by an orthogonal test and the quantity of extracted pigments was determined spectroscopically. The results show that: (1) among the six organic solvents, acetone was the most effective one for the extraction; (2) the optimum extraction conditions were as follows: the ratio of S/M (solvent volume/ material weight) was 30 ml/g; fresh seaweed was extracted 2 times in 2 h; (3) the average total content of pigments was 1.85 mg/g (calculated with dry L. japonica). 相似文献
100.
Sediments and surface water were sampled in a tide flat in the Huiquan Bay, Qingdao, China in January 2004 to simulate the exchange of NH4-N/NO3-N/PO4^3- between sediments and surface water. A working system was designed with which samples were shaken at 60, 120 and 150 revolutions per minute (r/min). Experiment results show that NH4-N concentration in water at shaking rate of 60 r/min decreased gradually, while at 120 r/min increased gradually. In resuspension, fine-grained sediments contributed most NH4-N to the seawater, followed by medium-grained and coarse-grained sediments. The NO3-N concentration in water had a negative relation with the shaking rate; the medium-grained sediments contributed more NO3-N to seawater than the coarse- and fine-grained sediments. The PO4^3- concentration is positively related with the shaking rate, the fine-grained sediments were the main N and P contributor to the seawater, followed by medium- and coarse-grained sediments. 相似文献