264 resultados para 26-1
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用X射线座滴照像法测量了铝液-氟化物熔盐间的界面张力。采用曲线拟合液滴轮廓坐标的计算机程序处理座滴图像。用逐步回归分析方法获得了计算熔盐密度值的回归方程。讨论了熔盐中NaF/AlF_3分子比,Li_2CO_3和稀土氧化物含量对熔盐-铝液间界面张力的影响。测量了铝液在熔盐中对石墨、工业碳块以及TiB_2涂层的润湿角。
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The family of fibrinogen-related proteins (FREPs) is a group of proteins with fibrinogen-like domains. Many members of this family play important roles as pattern recognition receptors in innate immune responses. The cDNA of bay scallop Argopecten irradians FREP (designated as AiFREP) was cloned by rapid amplification of cDNA ends (RACE) method based on the expressed sequence tag (EST). The full-length cDNA of AiFREP was of 990 bp. The open reading frame encoded a polypeptide of 251 amino acids, including a signal sequence and a 213 amino acids fibrinogen-like domain. The fibrinogen-like domain of AiFREP was highly similar to those of mammalian ficolins and other FREPs. The temporal expression of AiFREP mRNA in hemolymph was examined by fluorescent quantitative real-time PCR. The mRNA level of scallops challenged by Listonella anguillarum was significantly up-regulated, peaked to 9.39-fold at 9 h after stimulation, then dropped back to 4.37-fold at 12 h, while there was no significant change in the Micrococcus luteus challenged group in all periods of treatment. The function of AiFREP was investigated by recombination and expression of the cDNA fragment encoding its mature peptide in Escherichia coli Rosetta gami (DE3). The recombinant AiFREP (rAiFREP) agglutinated chicken erythrocytes and human A, B, O-type erythrocytes. The agglutinating activities were calcium-dependent and could be inhibited by acetyl group-containing carbohydrates. rAiFREP also agglutinated Gram-negative bacteria E. coli JM109, L anguillarum and Gram-positive bacteria M. luteus in the presence of calcium ions. These results collectively suggested that AiFREP functions as a pattern recognition receptor in the immune response of bay scallop and contributed to nonself recognition in invertebrates, which would also provide clues for elucidating the evolution of the lectin pathway of the complement system. (C) 2008 Elsevier Ltd. All rights reserved.
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In invertebrates, C-type lectins play crucial roles in innate immunity responses by mediating the recognition of host cells to pathogens and clearing microinvaders, which interact with carbohydrates and function as pattern recognition receptors (PRRs). A novel C-type lectin gene (LvLec) cDNA was cloned from hemocytes of Litopenaeus vannamei by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of LvLec was of 618 bp, consisting of a 5'-terminal untranslated region (UTR) of 60 bp and a 3'-UTR of 87 bp with a poly (A) tail. The deduced amino acid sequence of LvLec possessed all conserved features critical for the fundamental structure, such as the four cysteine residues (Cys(53), Cys(128), Cys(144), Cys(152)) involved in the formation of disulfides bridges and the potential Ca2+/carbohydrate-binding sites. The high similarity and the close phylogenetic relationship of LvLec shared with C-type lectins from vertebrates and invertebrates. The structural features of LvLec indicated that it was an invertebrate counterpart of the C-type lectin family. The cDNA fragment encoding the mature peptide of LvLec was recombined and expressed in Escherichia coli BL21(DE3)-pLysS. The recombinant protein (rLvLec) could agglutinate bacteria E. coli JM109 depending on Ca2+, and the agglutination could be inhibited by mannose and EDTA. These results indicated that LvLec was a new member of C-type lectin family and involved in the immune defence response to Gram negative bacteria in Litopenaeus vannamei. (C) 2008 Elsevier Ltd. All rights reserved.
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Sedimentary basins in the Yellow Sea can be grouped tectonically into the North Yellow Sea Basin (NYSB), the northern basin of the South Yellow Sea (SYSNB) and the southern basin of the South Yellow Sea (SYSSB). The NYSB is connected to Anju Basin to the east. The SYSSB extends to Subei Basin to the west. The acoustic basement of basins in the North Yellow Sea and South Yellow Sea is disparate, having different stratigraphic evolution and oil accumulation features, even though they have been under the same stress regime since the Late Triassic. The acoustic basement of the NYSB features China-Korea Platform crystalline rocks, whereas those in the SYSNB and SYSSB are of the Paleozoic Yangtze Platform sedimentary layers or metamorphic rocks. Since the Late Mesozoic terrestrial strata in the eastern of the NYSB (West Korea Bay Basin) were discovered having industrial hydrocarbon accumulation, the oil potential in the Mesozoic strata in the west depression of the basin could be promising, although the petroleum exploration in the South Yellow Sea has made no break-through yet. New deep reflection data and several drilling wells have indicated the source rock of the Mesozoic in the basins of South Yellow Sea, and the Paleozoic platform marine facies in the SYSSB and Central Rise could be the other hosts of oil or natural gas. The Mesozoic hydrocarbon could be found in the Mesozoic of the foredeep basin in the SYSNB that bears potential hydrocarbon in thick Cretaceous strata, and so does the SYSSB where the same petroleum system exists to that of oil-bearing Subei Basin.
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Characteristics and distribution patterns of elastic minerals (0.063 similar to 0.125 mm) in bottom sediments represent a significant indicator for the identification of the origin of sediment. One hundred and fourteen surface sediment samples, which were collected from the area near the Zhongsha Islands in the South China Sea, were analysed to identify the mineral suites and their distributions in the study area. The area can be divided into three mineral provinces: ( I) a province of biogenic minerals, which mainly originate from the Zhongsha Atoll; ( H) a province of volcanogenic minerals, which are mainly derived from local basaltic seamounts and small-scale volcanoes that are probably erupting, with some influences from the island-are volcanic region around the South China Sea; and (II) a mixed mineral province whose material source includes biogenic minerals, volcanogenic minerals and terrigenous minerals; the last province can be subdivided into a mixed mineral sub-province of the northeastern part of the study area, in which terrigenous minerals are mainly derived from China's Mainland and do not exceed 17 degrees N, and a mixed mineral sub-province of the southeastern part of the study area, in which terrigenous minerals are derived from Kalimantan and Indochina Peninsula and might be further transported into the deep sea basin through submarine canyons.
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As an important physical process at the air-sea interface, wave movement and breaking have a significant effect on the ocean surface mixed layer (OSML). When breaking waves occur at the ocean surface, turbulent kinetic energy (TKE) is input downwards, and a sublayer is formed near the surface and turbulence vertical mixing is intensively enhanced. A one-dimensional ocean model including the Mellor-Yamada level 2.5 turbulence closure equations was employed in our research on variations in turbulent energy budget within OSML. The influence of wave breaking could be introduced into the model by modifying an existing surface boundary condition of the TKE equation and specifying its input. The vertical diffusion and dissipation of TKE were effectively enhanced in the sublayer when wave breaking was considered. Turbulent energy dissipated in the sublayer was about 92.0% of the total depth-integrated dissipated TKE, which is twice higher than that of non-wave breaking. The shear production of TKE decreased by 3.5% because the mean flow fields tended to be uniform due to wave-enhanced turbulent mixing. As a result, a new local equilibrium between diffusion and dissipation of TKE was reached in the wave-enhanced layer. Below the sublayer, the local equilibrium between shear production and dissipation of TKE agreed with the conclusion drawn from the classical law-of-the-wall (Craig and Banner, 1994).
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Imaging mechanism of underwater topography by SAR and a underwater topography SAR detection model built on the theory of underwater topography detection with SAR image presented by Yuan Yeli are used to detect the underwater topography of Shuangzi Reefs in the Nansha Islands with three scenes of SAR images acquired in different time. Detection results of three SAR images are compared with the chart topography and the detection errors are analyzed. Underwater topography detection experiments of Shuangzi Reefs show that the detection model is practicable. The detection results indicate that SAR images acquired in different time also can be used to detect the underwater topography, and the detection results are affected by the ocean conditions in the SAR acquiring time.
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A new nonlinear integral transform of ocean wave spectra into Along-Track Interferometric Synthetic Aperture Radar (ATI-SAR) image spectra is described. ATI-SAR phase image spectra are calculated for various sea states and radar configurations based on the nonlinear integral transform. The numerical simulations show that the slant range to velocity ratio (R/V), significant wave height to ocean wavelength ratio (H-s/lambda), the baseline (2B) and incident angle (theta) affect ATI-SAR imaging. The ATI-SAR imaging theory is validated by means of Two X-band, HH-polarized ATI-SAR phase images of ocean waves and eight C-band, HH-polarized ATI-SAR phase image spectra of ocean waves. It is shown that ATI-SAR phase image spectra are in agreement with those calculated by forward mapping in situ directional wave spectra collected simultaneously with available ATI-SAR observations. ATI-SAR spectral correlation coefficients between observed and simulated are greater than 0.6 and are not sensitive to the degree of nonlinearity. However, the ATI-SAR phase image spectral turns towards the range direction, even if the real ocean wave direction is 30 degrees. It is also shown that the ATI-SAR imaging mechanism is significantly affected by the degree of velocity bunching nonlinearity, especially for high values of R/V and H-s/lambda.
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为揭示渤海沉积物中氮的生物地球化学循环过程,本文应用自然粒度下的分级分离浸取方法首次对渤海沉积物中氮的形态进行了研究,获得了氮形态分布的地球化学特征;将沉积物氮中可转化和非转化部分定量区别开,并对可转化态中各形态氮对其循环贡献的大小进行了评估;结合底栖生物的分布初步探计了沉积物中氮与生物生产的关系及底栖生物对氮循环的影响。得到的主要结论包括:渤海沉积物中氮的形态分布特征及其控制因素。表层沉积物中IEF-N、CF-N、IMOF-N和OSF-N占TN的比例分别为3.67%,0.31%,0.42%和26.45%,OSF-N是可转化态氮的优势形态。IEF-N 中NH_4~+和NO_3~-具有不同的成岩机制:NH_2~+主要受OC、Es和粘土矿物性质影响,NO_3~-与水体分布密切相关。CF-N含量最小,主要受沉积环境pH值的影响。IMOF-N主要由NH_4~+在Fe~(3+)上的吸附形成,受沉积物的氧化还原环境控制。OSF-N除与物质来源有关外,受到粘土矿物性质及沉积物粒度的影响。Fe、Mn和Co对IEF-N和IMOF-N的成岩作用影响明显,Cu、Pb和Mo对OSF-N的分布产生影响,二者作用的机理不同。表层样中,约69.15%的氮经过早期成岩作用而埋藏,短期内不再参与循环。氮的埋藏通量与沉积物聚积速率呈显著正相关,同时受温度、Eh、OC、盐度、硫化物含量等因素影响。沉积物中C/N和N/P均呈现异常的低值,前者主要是由于沉积物中保留了大量的无机氮,后者主要因为陆地排放大量磷入海以及磷的埋藏效率高于氮所致。柱状样中,IEF-N基本随深度减小,IMOF-N随深度有突变现象,OSF-N随深度的变化表明了矿化作用进行的程度。对沉积物中生源要素分解速率常数有:N>P>C>Si。表层沉积物中可转化态氮占总氮的比例高于深层沉积物。OC/ON随深度减小表明沉积物通过某种机制富集了有机氮。各形态氮在氮循环中作用及渤海氮循环收支。对渤海沉积物中可转化态氮的量进行了估算,IEF-N、CF-N、IMOF-N和OSF-N分别为3.657 * 10~8kg,2.794 * 10~7 kg,3.832 * 10~7kg和2.372平共处* 10~9kg;结合室内模拟的氮的界面交换通量,估算其完全释放所需的时间分别为2.15a,0.16a,0.225a和13.94a。各形态氮释放的顺序与其结合牢固程度一致,即IEF-N>CF-N >IMOF-N>OSF-N,其对界面交换的贡献大小则随时间尺度大小发生变化:随时间尺度增加,IEF-N、CF-N、IMOF-N的贡献逐渐减小,OSF-N的贡献逐渐增大,当时间尺度大到足以使四态氮完全释放时,其贡献的大小与各形态氮的量一致即OSF-N(84.6%)>IEF-N(13.0%)>IMOF-N(1.4%)>CF-N(1.0%)。非转化态氮占总氮的 69.15%,其中由于颗粒物包裹导致的“非转化态”氮为49%,说明粒度的影响非常重要。IEF-N和OSF-N主要存在于颗粒物质外层,是循环的主要参与者,CF-N和IMOF-N绝大部分在内层,对循环的贡献很小。水体中再循环的氮对初级生产力的贡献(74.4%)比沉积物中再循环氮的贡献 (26.1)大得多,二者对生态系统的作用不同,水体再生的营养盐通常在较长的时间尺度上维持初级生产力的平衡,而沉积物中的再生则在很短的时间内通过强烈的混合作用提高初级生产力。沉积物中氮与生物生产的关系及底栖生物对沉积物氮循环的影响。IEF-N和OSF-N的分布均与初级生产力以及浮游植物个体数量的分布具有一定的相似性。沉积物中的IEF-N的作用相当于一个氮营养盐的“储存库”对初级生产力产生影响,其作用机制类似于水体富营养化的正反馈机制。IEF-N能对赤潮的发生起加速作用。底栖生物的分布与氮形态分布具有正的相关性:莱洲湾内IEF-N和OSF-N的分布与该区域高生物量和高密度的大型底栖动物分布一致,说明在底栖生物活动活跃的区域营养盐的再生和流动是高效而迅速的。生物扰动能加速矿化作用的进行,使沉积物在一定深度范围内NH_4~+含量增加,大型底栖动物的灌溉作用使NO_3~-在深层仍有较高的分布。底栖生物的不同种群对营养盐变化的响应不同。
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变态过程是双壳贝类由幼虫向成体转变的一个必不缺少的发育阶段。研究双壳贝类幼虫的变态过程及其机理,对于阐明它们的种群数量变动,促进重要经济双壳贝类增养殖的发展有重要的理论和实践意义。本论文除了用化学物质对几种双壳贝类(海湾扇贝、墨西哥湾扇贝和硬壳蛤)幼虫的变态进行诱导外,主要以激素和神经递质的作用方式为基础,通过直接测定双壳贝类(以海湾扇贝为代表)幼虫体内激素和神经递质、第二信使cAMP等生化物质含量的变化来研究双壳贝类幼虫变态过程中的信息传递途径,从分子生物学和神经生物学角度阐明双壳贝类幼虫变态机理。主要结果如下:1.通过参考国内外大量文献的基础上,较为系统地评述了近二十年来海洋无脊椎动物幼虫附着变态研究的一些进展情况,主要包括诱导因子、附着变态机理模型、人工诱导物的应用和延迟变态四个方面。到目前为止,人们已经发现了许多海洋无脊椎动物幼虫附着变态的诱导物质,主要分为天然诱导物和人工诱导物两大类,一些人工诱导物如GABA、肾上腺素和去甲肾上腺素已经在经济贝类苗种生产中得到应用。幼虫附着变态机理模型主要有长牡蛎(Crassostrea gigas)幼虫附着变态的双调控模型、红鲍(Haliotis rufescens)幼虫附着变态的上行调节模型以及多毛类Phragmatopoma california幼虫附着变态的脂肪酸调控模型。本论文还评述了海洋无脊椎动物幼虫发生延迟变态的原因以及延迟变态对海洋无脊椎动物造成的影响,并提出了解决的方法和今后研究的重点问题。2.在室内用氯化乙酰胆碱、ATP和CaCl_2 3种化学物质对海湾扇贝幼虫的变态进行了诱导实验。结果表明,虽然在个别浓度和处理时间氯化乙酰胆碱和ATP有诱导作用,但总体诱导效果不显著。而10×10~(-3)~40×10~(-3M的CaCl_2在处理12~24h后诱导效果较显著,其诱导效果对处理时间的依赖性较显著,在浓度为40×10~(-3)M和处理时间为24h时诱导效果最好,与对照组相比,变态率提高23.18%。3种诱导物对幼虫死亡率均有显著影响,并且死亡率对浓度和处理时间均有显著的依赖性,浓度越高,处理时间越长,死亡率越高。3.用KCl、肾上腺素、去甲肾上腺素和氯化胆碱进行了墨西哥湾扇贝(Argopectenirradians concentricus Say)幼虫变态的诱导作用实验。结果表明,KCl、肾上腺素、去甲肾上腺素和氯化胆碱对墨西哥湾扇贝幼虫变态均有显著诱导作用。KCl在处理时间为12h~48h范围内均有诱导作用;13.42×10~(-3)M和20.13×10~(-3)M的KCl诱导效果较好,变态率平均提高10%以上。1.O×10~(-6)M~50×10~(-6)M的肾上腺素在处理时间为lh~12h较适宜,此时变态率均提高10%以上。1.0×10~(-6)M~50×10~(-6)M的去甲肾上腺素在处理时间为1h~24h都较适宜,变态率平均均提高10%以上,最高可提高31.07%。0.01×10~(-4)M~1.O×10~(-4)M的氯化胆碱在处理时间为12h~48h时诱导效果均较好,它们之间的平均变态提高率并没有显著差别,均在12%~13%之间。10×10~(-4)M的氯化胆碱在处理时间为12h时诱导效果较明显,变态率可以提高19.14%,超过12h,变态率明显下降,100×10~(-4)M的氯化胆碱明显产生毒害作用,幼虫变态率均为零,而幼虫的死亡率均为100%。4.用KCl、肾上腺素、去甲肾上腺素、L-DOPA、5-羟色胺(5-hydroxytryptamine,Serotonin,5-HT)和GABA(γ-氨基丁酸)进行了不同浓度不同处理时间对硬壳蛤(Mercenaria mercenaria L.)幼虫变态诱导实验。结果表明,KCl、肾上腺素、去甲肾上腺素、L-DOPA和5-羟色胺对硬壳蛤幼虫的变态均有诱导作用,而GABA的诱导 作用不显著。KCl的最佳诱导浓度随处理时间不同而有所不同。当处理时间为1~24h时,KCl的最佳诱导浓度为33.56×10~(-3)M,此时幼虫变态率均提高24%以上,当处理时间为48h时,KCl的最佳诱导浓度为20.13~26.85×10~(-3)M,处理时间为72h时,最佳诱导浓度为13.42×10~(-3)M。肾上腺素和去甲肾上腺素的诱导作用与浓度和处理时间均有关。肾上腺素的最佳处理浓度为100×10~(-6)M,最佳处理时间均为8h,此时幼虫变态率提高最大,为36.97%。当去甲肾上腺素的诱导浓度为100×10~(-6)M,处理时间为8h~16h时,幼虫变态提高率较高,均大于18%,死亡提高率均低于30%,当去甲肾上腺索诱导浓度为500×10~(-6)M时,虽然在8h~16h的处理时间范围内,幼虫变态提高率也较高,均大于18%,但当处理时间超过8h,在16~48h范围内,幼 虫死亡提高率明显升高,均大于50%。L-DOPA的适宜诱导浓度为10×10~(-6)M~50×10~(-6)M,适宜处理时间为8~24h,此时幼虫变态率均提高30%以上,最高可提高79.43%。5-羟色胺的诱导作用较强,其适宜诱导浓度为100×10~(-6)M—1000×10~(-6)M,适宜处理时间为0.5~24h,此时幼虫变态率提高均在30%以上,当处理时间为8h时,最佳诱导浓度为1000×10~(-6)M,此时幼虫变态率提高57.5%,当处理时间为24h时,最佳诱导浓度为100×10~(-6)M,此时幼虫变态率提高69.29%。GABA的诱导作用较弱,最佳诱导浓度随处理时间的不同而有所不同。处理时间为24h和48h时,最佳诱导浓度为0.1×10~(-6)M;处理时间为0.5~16h时,最佳诱导浓度为100×10~(-6)M。5.KCl、肾上腺素、去甲肾上腺索、L-DOPA、5-羟色胺、GABA、茶碱和咖啡因8种诱导物对不同发育阶段海湾扇贝幼虫变态的诱导作用是不同的。13.42×10~(-3)M和20.13×10~(-3)M的KCl对第12天幼虫的变态有抑制作用,变态提高率为负值;之后当幼虫发育至第13和14天时,两浓度的KCl能够明显诱导幼虫变态,变态提高率均高于20%,而对于第16天的幼虫诱导作用有所减弱,变态提高率有所降低;26.85×10~(-3)M的KCl对第12和13天幼虫的变态均有抑制作用,变态提高率为负值,对第14和16天幼虫的变态却有明显的持续的诱导作用,变态提高率分别为22.98%和37.5%。神经递质肾上腺素、去甲肾上腺素、L-DOPA、5-羟色胺和GABA的诱导作用规律基本相似,即对第13天海湾扇贝幼虫的变态有明显的抑制作用,变态提高率均为负值,而对第14天幼虫的诱导作用较显著。茶碱和咖啡因作为影响细胞内cAMP的物质,它们的诱导作用规律与神经递质有所不同。它们对第13天海湾扇贝幼虫变态的诱导效果最好。6.测定了不同发育阶段及人工诱导后海湾扇贝幼虫体内去甲肾上腺素、多巴胺和5-羟色胺含量的变化规律。结果表明,海湾扇贝幼虫体内去甲肾上腺索含量在变态前和变态后没有明显变化,变态前为2352(pg/mg湿重),变态后为2770(pg/mg湿重)。多巴胺和5-羟色胺含量在变态前随幼虫的发育而增加,变态前(第13天)急剧增加,第13天的幼虫比第12天的幼虫分别增加了2.8倍和5.7倍,变态后急剧下降,变态后幼苗比第13天的幼虫分别降低了25.1倍和16.4倍。海湾扇贝幼虫体内DA:NE比和5-HT:NE比在变态前和变态后变化比较剧烈。DA:NE比和5-HT:NE比在变态前(第13天)急剧增加,第13天的幼虫比第12天的幼虫增加了3.O倍(DA:NE比)和5.0倍(5-HT:NE比);变态后急剧降低,变态后幼苗比第13天的幼虫降低了29.8倍(DA:NE比)和19.5倍(5-HT:NE比)。海湾扇贝幼虫经KCl和氯化钙诱导24h后,体内去甲肾上腺素、多巴胺和5-羟色胺以及DA:NE比和5-HT:NE比均有所降低。本实验的结果表明,多巴胺和5-羟色胺可能启动了海湾扇贝幼虫的变态过程。7.茶碱和咖啡因对墨西哥湾扇贝幼虫的变态均有明显诱导作用。它们的诱导作用均对浓度的依赖性较强,对处理时间的依赖性较弱。10×10~(-4)M的茶碱诱导效果最好,平均变态提高率达33%,其次为1.0×10~(-4)M和100×10~(-4)M的茶碱,平均变态提高率分别为23.15%和21.97%。处理时间对茶碱诱导效果影响不显著,在1~24h范围内,平均变态提高率在19.07~26.1%之间变动。10×10~(-4)M的咖啡因诱导效果最佳,4个处理时间的平均变态提高率为36.01%,其次为100×10~(-4)M,平均变态提高率为26.43%。处理时间对茶碱的诱导效果影响不大,在1~24h范围内,平均变态提高率在19.65~22.02%之间变动。8.采用直接测定cAMP的方法来研究cAMP是否参与了海湾扇贝幼虫的变态过程。结果表明,cAMP参与了海湾扇贝幼虫的变态过程。海湾扇贝幼虫体内cAMP含量随着发育阶段的不同而有所变化。在D形幼虫期最低,为73 pmol/(mg蛋白质);当到达壳顶期幼虫时cAMP含量明显增加,比D形幼虫期提高了12.7倍。从壳顶期幼虫到眼点幼虫(100%,第13天)cAMP含量增加速度较慢,各发育阶段分别比前一发育阶段增加了0.4倍、0.3倍和0.2倍。但当幼虫变态后,体内cAMP含量又急剧增加,幼苗体内cAMP含量比眼点幼虫(100%,第13天)增加了6.1倍。当用KCl、肾上腺索和L-DOPA诱导后,幼虫体内cAMP含量明显增加,分别比对照组提高了7.8倍、1.5倍和10.7倍,说明cAMP参与了这3种诱导物诱导海湾扇贝幼虫变态的过程。9.在前面实验结果和参考有关文献的基础上,初步提出了以海湾扇贝为代表的双壳贝类幼虫变态机理模型:幼虫变态分为两个过程:启动过程和后续过程。当幼虫发育到一定阶段,在外界刺激因子的作用下,体内分泌多巴胺和5-羟色胺,多巴胺和5-羟色胺通过某种信号转导途径(如以DG和IP_3为第二信使)启动变态过程,变态过程启动后,又激活以cAMP为第二信使的信号转导途径(暂时称为后续过程),两者共同完成了幼虫的变态过程。
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海藻是海洋生物中的一大类群,由于其特殊的生活环境,能够代谢产生大量结构独特多变和活性特殊多样的代谢产物,是化学和生物活性多样性研究的重要对象之一。我国海域辽阔,海藻资源丰富,为寻找结构新颖、生理活性独特的先导化合物,加强对海藻资源的开发利用,本论文对中国沿海的三种海洋红藻进行了化学成分和生物活性研究,同时对山东青岛海域生物量丰富的一种海洋红藻松节藻进行了动物体内抗糖尿病活性研究。 利用正相硅胶柱色谱、Sephadex LH-20柱色谱以及反相HPLC和重结晶等现代分离手段,对山东青岛沿海的红藻扇形叉枝藻(Gymnogongrus flabelliformis)进行了系统的化学成分研究,从中得到单体化合物26个,通过波谱学方法(IR、MS、NMR等)鉴定了他们的结构,分别为(3R,6R,7E)-(+)-3-O-phenylacetyl- 4,7-megastigmadiene-9-one(1),(3R,7E)-(-)-3-O-phenylacetyl-5,7-megastigmadiene -9-one(2),(3S,6R,7E)-(+)-3-hydroxyl-4,7-megastigmadien-9-one(3),(3S,5R,6S,7E)- (-)-3-hydroxy-5,6-epoxy-7-megastigmene-9-one(4),(3S,5S,6R,7E)-(+)-3-hydroxy- 5,6-epoxy-7-megastigmene-9-one(5),Dehydrovomifoliol(6),(3R)-(-)-4-[(2R,4S)-4- acetoxy-2-hydroxy-2,6,6-trimethylcyclohexylidene]-3-buten-2-one(7),2,3,3′-三溴-4,4′,5,5′-四羟基-1′-乙氧甲基双苯基甲烷(8),2,2′,3,3′-四溴-4,4′,5,5′-四羟基双苯基甲烷(9),3-溴-4,5-二羟基苯甲醛(10),2,3-二溴-4,5-二羟基苯甲基甲醚(11),2,3-二溴-4,5-二羟基苯甲醇(12),N, N-二甲基酪胺(13),4-羟基苯甲酸乙酯(14),4-羟基苯甲基乙醚(15),4-羟基苯乙基乙酯(16),4-羟基苯乙酸甲酯(17),4-羟基苯甲醛(18),豆甾-4-烯-3-酮(19),胆甾-4-烯-3-酮(20),胆甾醇(21),尿嘧啶(22),尿嘧啶核苷(23),腺嘌呤核苷(24),丁二酸(25),5-羟基-4-甲基-5-戊基-2,5-二氢呋喃-2-酮(26)。其中化合物1、2为新化合物,化合物3为新天然产物,所有化合物均为首次从该属海藻中分离得到。通过 MTT 法对部分单体化合物进行了肿瘤细胞毒活性筛选, 结果表明,化合物8、9、10、12对筛选的所有细胞株均有较强细胞毒活性,化合物11对人肺癌细胞株(A549)、人肝癌细胞株(Bel 7402)、人结肠癌细胞株(HCT-8)有一定细胞毒活性。通过研究单体化合物对小鼠腹腔巨噬细胞TNF-分泌的影响,对其进行抗炎活性筛选,结果表明,化合物8、9、11、13、17、23、24、25对小鼠腹腔巨噬细胞TNF-分泌表现出明显的抑制作用。 从采自山东荣成镆铘岛的红藻小珊瑚藻(Corallina pilulifera)的乙酸乙酯萃取物中分离得到16个单体化合物,通过波谱学方法鉴定化合物结构14个(另外2个正在鉴定中),分别为2α-乙氧酰基-2β-羟基-A-降胆甾-5-烯-4-酮(27),胆甾-4-烯-3-酮(28),胆甾醇(29),3β-羟基-胆甾-5,24(28)-二烯-7-酮(30),2α-羟基-胆甾-4-烯-3-酮(31),6α-羟基-胆甾-4-烯-3-酮(32),3β-羟基-胆甾-5-烯-7-酮(33),(E)-phytol epoxide(34),Phytenal(35),3,7,11,15- tetramethyl-hexadec-2-en-1-oll(Phytol)(36),Loloilide(37),(3S,5R,6S,7E)-(-)-3-hydroxy-5,6-epoxy-7- megastigmene-9-one(38),Dehydrovomifoliol(39),4-羟基苯甲醛(40)。其中,化合物 31为新天然产物,化合物27为首次从植物中分离得到,所有化合物均为首次从该种海藻中分离得到。通过 MTT 法对分离得到的单体化合物进行了肿瘤细胞毒活性筛选,化合物27和化合物32对筛选的所有肿瘤细胞株均有细胞毒活性,且化合物27对人胃癌细胞株(BGC-823)、人结肠癌细胞株(HCT-8)和人卵巢癌细胞株(A2780)具有中等强度抑制活性。化合物28、化合物31和化合物33对人肝癌细胞株(Bel 7402)、人结肠癌细胞株(HCT-8)和人卵巢癌细胞株(A2780)有一定细胞毒活性。 从采自广西北海涠洲岛的多管藻Polysiphonia sp.的乙酸乙酯萃取物中分离得到6个单体化合物,通过波谱学方法鉴定化合物结构5个(另外1个仍在鉴定),分别为胆甾醇(41),3,7,11,15-tetramethyl-hexadec-2-en-1-ol(Phytol)(42),3-吲哚甲醛(43),4-羟基苯甲醛(44),4-羟基苯甲酸(45)。 对山东青岛沿海的松节藻 (Rhodomela confervoides) 乙醇提取物进行了初步的体内抗糖尿病活性研究,采用链脲佐菌素诱导的2型糖尿病(STZ-DM)大鼠模型对其进行体内降糖实验,结果发现,松节藻乙醇提取物在糖尿病大鼠体内不仅具有显著的降血糖作用,且呈现良好的量–效关系,而且能够纠正糖尿病引发的物质代谢紊乱,增加体重,提高试验动物的成活率,因此具有良好的应用开发前景。
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本文在实验室条件下,系统地研究了温度盐度对栉孔扇贝胚胎和幼虫的单一和组合效应。受精卵孵化的适宜温度范围为16.0-22.0 ℃,适宜盐度范围为27.5-32.5‰。随着胚胎发育,胚体对度盐度的适应范围增广。胚胎孵化的适宜温--盐区域为16.0 ℃/27.2‰-24.4 ℃/33.6‰。水温超过26.0 ℃时,幼虫存活率显著下降,其生长的适宜温度范围为16.0-26.0℃。幼虫存活的适宜盐度范围为27.0-42.0‰,生长的适宜盐度范围为27.0-39.0‰。在120小时实验中,幼虫存活的适宜温--盐区域是10.0 ℃/16.3‰-27.0 ℃/42.0‰,生长的适宜的温--盐区域是21.5 ℃/26.1‰-27.0 ℃/36.0‰。在240小时实验中,幼虫存活的适宜温--盐区域是10.0 ℃/23.4‰-26.9 ℃/42.0‰,生长的适宜的温--盐区域是14.2 ℃/20.5‰-27.6 ℃/38.8‰。温度盐度对胚胎和幼虫的影响都很大,相比较而言,盐度的影响大于温度。温--盐对胚胎发育和幼虫存活的组合效应极其显著。随着幼虫的生长发育,温--盐对幼虫生长的组合效应逐渐表现出显著性,幼虫生长的适应范围增大。
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The spatial distribution of some large tintinnid species (nominally>76 mu m) was investigated according to samples collected by vertical towing in cruises to the southern Yellow Sea in summer 2000-2002 and 2004. Eight species were identified: Codonellopsis mobilis, Leprotintinnus netritus, Tintinnopsis karajacensis, T. japonica, T. kiaochowensis, T. butschlii, T. radix, and Parafavella sp. With maximum abundance of 158.2 ind/L in June 2004, C mobilis was the dominant species, lasting from May to July 2004. Tintinnid communities were patchy and distributed mainly in shallow waters along the shore.
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The adsorption and desorption of algae Cladophora fascicularis and their relation with initial Cd2+ concentration, initial pH, and co-existing ions were studied. Adsorption equilibrium and biosorption kinetics were established from batch experiments. The adsorption equilibrium was adequately described by the Langmuir isotherm, and biosorption kinetics was in pseudo-second order model. The experiment on co-existing ions showed that the biosorption capacity of biomass decreased with an increasing concentration of competing ions. Desorption experiments indicated that EDTA was efficient desorbent for recovery from Cd2+. With high capacities of metal biosorption and desorption, the biomass of Cladophora fascicularis is promising as a cost-effective biosorbent for the removal of Cd2+ from wastewater.
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The impact of astaxanthin-enriched algal powder on auxiliary memory improvement was assessed in BALB/c mice pre-supplemented with different dosages of cracked green algal (Haematococcus pluvialis) powder daily for 30 days. The supplemented mice were first tested over 8 days to find a hidden platform by swimming in a Morris water maze. Then, for 5 days, the mice were used to search for a visible platform in a Morris water maze. After that, the mice practised finding a safe place-an insulated platform in a chamber-for 2 days. During these animal experimental periods, similar algal meals containing astaxanthin at 0, 0.26, 1.3 and 6.4 mg/kg body weight were continuously fed to each group of tested mice. Profiles of latency, distance, speed and the direction angle to the platforms as well as the diving frequency in each group were measured and analyzed. The process of mice jumping up onto the insulated platform and diving down to the copper-shuttered bottom with a 36 V electrical charge were also monitored by automatic video recording. The results of the Morris maze experiment showed that middle dosage of H. pluvialis meals (1.3 mg astaxanthin/kg body weight) significantly shortened the latency and distance required for mice to find a hidden platform. However, there was no obvious change in swim velocity in any of the supplemented groups. In contrast, the visible platform test showed a significant increase in latency and swim distance, and a significant decrease in swim speed for all groups of mice orally supplemented with H. pluvialis powder compared to the placebo group (P < 0.05 or P < 0.01). Mice supplemented with the algal meal hesitantly turned around the original hidden platform, in contract to mice supplemented with placebo, who easily forgot the original location and accepted the visible platform as a new safe place. These results illustrate that astaxanthin-enriched H. pluvialis powder has the auxiliary property of memory improvement. The results from the platform diving test showed that the low and middle dosage of H. pluvialis powder, rather that the high dosage, increased the latency and reduced the frequency of diving from the safe insulated platform to the electrically stimulated copper shutter, especially in the low treatment group (P < 0.05). These results indicate that H. pluvialis powder is associated with dose-dependent memory improvement and that a low dosage of algal powder (<= middle treatment group) is really good for improving the memory.