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甲壳质/壳聚糖硫酸酯研究进展 总被引：5，自引：1，他引：4
人们希望能够找到或合成能够代替肝素的物质,以解决肝素资源有限问题,在众多的衍生物当中,甲壳质、壳聚糖磺化修饰成为最诱人的领域,由于壳聚糖具有独特的分子结构,比其他多糖更适合于制备肝素类物质,因此科学家对甲壳质、壳聚糖选择性磺化,对它们的构效关系,生物活性与应用开发进行了大量研究,以期在海洋药物领域获得突破。１甲壳质／壳聚糖硫酸酯的理化性质甲壳质是一种天然高分子多糖,存在于各种节肢动物（虾、蟹、昆虫等）的甲壳中,在褐煤中曾找到约２５０×１０４ａ前各种甲虫翅膀的残余,可见甲壳质对细菌作用十分稳定。这… 相似文献
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壳聚糖及其衍生物在生物工程领域中的应用研究 总被引：7，自引：0，他引：7
壳聚糖是甲壳质部分和全部脱乙酰基的产物 ,由于其分子中含有 ＯＨ和 ＮＨ ２,所以可酰基化、磺化、羧甲基化、羟基化、酯化、醚化、交联、螯合等 ,获得溶解性和生物活性不同的衍生物 ,从而拓宽了壳聚糖的应用领域。本文对壳聚糖及其衍生物在生物工程领域中的应用研究进行评述。１在细胞工程领域中的应用研究利用动物细胞大规模培养技术，可以制备出稀有的生化药物和细胞活性因子等医疗产品。微载体是直径在６０～２５０μｍ能够适于贴壁细胞在其上附着生长的微珠 ,研究表明 ,壳聚糖是一种新型的细胞大规模培养用优质材料。ＳｃｈｏｌｚＭ… 相似文献
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褐藻酸钠硫酸酯是以褐藻酸为原料合成的硫酸酯钠盐系列物。首次报道该系列化合物（Ⅰ,Ⅱ,Ⅲ,Ⅳ,主要是Ⅰ）的抗血栓和抗凝血作用。实验发现,褐藻酸钠硫酸酯系列物均有抗凝血作用。其作用具有浓度和磺化度依赖性。实验测定化合物Ⅰ,Ⅱ,Ⅲ,Ⅳ的抗凝效价,分别相当于肝素钠的22．5％,16．7％,11．1％和11．7％。以该化合物10mg·kg－1静脉注射能增加小鼠的出血量并能抑制大鼠实验性动脉血栓的形成。化合物Ⅰ还具有延长大鼠凝血酶原时间和抑制静脉血栓形成的作用。结果提示：褐藻酸钠硫酸酯的抗凝血与抗血栓作用的活性基团可能为该化合物上的硫酸根,具有肝素样作用。 相似文献
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制备不同脱乙酰度、分子质量的壳聚糖固体粉末和溶液,并利用试管法比较了不同浓度、不同性质及不同状态的样品的体外凝血时间.结果表明:当分子质量相近时,壳聚糖溶液的体外凝血时间随脱乙酰度的增加而减少,脱乙酰度中等的固体粉末具有最强的促凝血能力;当脱乙酰度相近时,只有高分子质量的壳聚糖溶液具有一定的促凝血活性,但固体粉末状态的三种壳聚糖均具有一定的缩短体外凝血时间的能力;同等剂量的壳聚糖溶液和粉末,除了高脱乙酰度、高分子质量的壳聚糖外,其余样品的固体粉末对于缩短体外凝血时间更为有效 相似文献
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壳聚糖硫酸酯制备方法 总被引：8，自引：0，他引：8
壳聚糖是甲壳素脱乙酰基的产物，本身可生物降解，具有良好的生物相容性。经过硫酸化引入SO4^2-基团。给予化合物重要生理功能，使其具有增强机体免疫力，抑制肿瘤，抑制病毒，降糖降脂，抗凝血，防治血栓，治疗溃疡和肾衰等方面的作用，国内外对其开发十分活跃，作者就壳聚糖硫酸酯的理化性质和几种制备方法进行介绍。 相似文献
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甲壳质(chitin)，又名甲壳素，几丁质，主要存在于虾、蟹、蛹及昆虫等动物外壳中。其衍生物壳聚糖(chitosan)又名甲壳胺或脱乙酰甲壳素，是甲壳质经脱乙酰化反应制得的产物，是最基本、最重要的甲壳质衍生物。
壳聚糖具有良好的吸湿性、成膜性、气透性、降解性、生物相溶性、无毒副作用以及不污染环境的优良性质，广泛应用于环保、食品、化工、医药、纺织、造纸、卷烟、农业、化妆品、印染、生物医学、酶制剂、保健品、金属回收等许多行业中。因此甲壳质作为一种纯天然的自然资源，对其开发和应用具有极其深远的意义。但甲壳质及其壳聚糖的高度不溶性极大地限制了它们的应用，必须对它们进行化学深加工，或结构修饰，引入或改变其分子链上的某个基团，或者完全降解或部分降解其分子链，从而得到一些具有特殊性质、水溶性有所改善的衍生物产品来满足人们的使用需要，因此甲壳单糖随之问世。
D-氨基葡萄糖盐酸盐(GAH)是甲壳质或壳聚糖的降解产物，其结构为D-葡萄糖分子中C2-羟基被氨基所取代，因氨基显碱性，与盐酸结合成盐。D-氨基葡萄糖盐酸盐是重要的生化试剂和医药中间体，其用途十分广泛：对人体具有重要的生理功能，它参与肝肾解毒，发挥抗炎护肝的作用；它能促进抗生素药剂的注射功能，也可作为糖尿病患者的营养补助剂，大剂量使用对宿主组织无害，但对体内恶性细胞却是一种细胞毒；它促进人体黏多糖的合成，改善关节软骨的代谢及修复；此外，它还可作为化妆品和饲料的添加剂。目前，国内、外对D-氨基葡萄糖的需求日益增加。
本文论述了甲壳质和壳聚糖的制备技术，并着重研究了单糖的最优化制备方法，通过正交实验，进行了3因素6水平72(36×2)个实验；同时研究了抽滤工艺和脱色工艺对产品质量的影响，为今后高质量的生产D-氨基葡萄糖盐酸盐及工业化提供了技术指导。 相似文献
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一种甲壳素硫酸酯制备条件的研究 总被引：4，自引：0，他引：4
由于甲壳素的水不溶性特点，使其应用受到一定的限制，因此改性甲壳素的开发更受到重视。甲壳素硫酸酯属改性甲壳素，具有类肝素的功能，如：抗炎，抗凝血，降血脂，降低毛细血管的通透性等。本文主要研究了水溶性甲壳素硫酸酯的制备条件［１］为甲壳素的进一步应用提供理论依据。１材料与方法１．１材料自制甲壳素（脱乙酰度分别为８０．４％，５８％，４５．２％，２０．８％）；浓硫酸（化学纯）；氢氧化钠（化学纯）；无水乙醇。１．２仪器与设备标准口四口圆底烧瓶；搅拌机；旋转蒸发器；阴阳离子交换脂。１．３有机硫测定方法称取干燥… 相似文献
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甲壳素是一种天然高分子多糖，具有与纤维素相近的骨架结构，其资源丰富，用途广泛(方波，1998)。但由于分子内和分子间存在很强的氢键作用力，因而不能熔融，也不溶于普通溶剂(如水、乙醇等)(董炎明等，2002)，实际应用中较多的是其部分或全部脱乙酰化产物——壳聚糖。壳聚糖虽然可以溶于酸性水溶液，但不能直接溶于水中，且在酸性水溶液中不稳定，也不溶于一般的有机溶剂，这在很大程度上限制了它的应用(董炎明等，2002)。所以，水溶性壳聚糖衍生物的研制正成为一个新的研究方向。壳聚糖分子中C2位上的-NH2，C3、C6位上的-OH，均具有较强的反应活性，在适当条件下可进行多种化学修饰，如酰基化、羧烷基化、硫酸酯化、烷基化、羟烷基化及氰烷基化等。引入上述功能性基团，可增加壳聚糖的溶解性和功能性，拓宽了壳聚糖的应用范围。这些衍生物的制备研究已成为壳聚糖应用开发的主要方向之一。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献