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本文采用三检测器联用凝胶色谱法对κ-型、ι-型卡拉胶的分子量进行测量（κ-型、ι-型卡拉胶的分子量分别为685.77 kDa和408.33 kDa）。通过研究两种卡拉胶稀溶液的Mark-Houwink指数、流体力学直径,得出了κ-型和ι-型卡拉胶的分子构象：在低分子量阶段,卡拉胶分子链刚性较强,呈现刚性棒状结构;在中分子量阶段,卡拉胶分子链的刚性降低,构象介于无规线团与刚性棒状结构之间,呈现半刚性的伸展线团;在高分子量阶段,卡拉胶分子呈现出无规线团构象。随着卡拉胶分子量的增加,卡拉胶分子链的刚性逐渐降低,卡拉胶分子由刚性棒状结构变为半刚性延展线团最终变为柔性无规线团,且κ-型和ι-型卡拉胶分子链表现出相同的变化趋势。卡拉胶的分子量和构象对卡拉胶的抗菌抗凝等生物活性以及纺丝性能有着较大的影响,对卡拉胶分子量和构象进行准确分析可以促进卡拉胶在纺织、医药、化妆品等工业生产中的应用。 相似文献
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本文研究了雌配子体和四分孢子体两种世代角叉菜卡拉胶的季节变化。不论雌配子体还是四分孢子体角叉菜,其卡拉胶的产率都是夏、秋季高,冬季低。四分孢子体卡拉胶不凝固,雌配子体卡拉胶的凝胶强度是7和12两月的较高,其凝固点没有季节性变化。四分孢子体卡拉胶的粘度在秋、冬季较高,雌配子体的粘度无季节变化。雌配子体和四分孢子体卡拉胶的3,6-AG含量都是夏、秋季较高,冬季较低。硫酸基含量都是秋季的稍高。 上述结果证明,世代是决定角叉菜卡拉胶的物理性质和化学组成最主要的因素,当世代相同时,季节对所含卡拉胶的产率、物理性质和化学组成也有不同程度的影响。 相似文献
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用~(13)C-核磁共振(~(13)C-NMR)和红外(IR)光谱分析了从三种卡拉胶原藻(鹿角沙菜、角叉菜、异枝麒麟菜)分步提取的主要卡拉胶级分的化学结构。~(13)C-NMR谱图表明,所有主要级分由k-卡拉胶组成,除此之外,沙菜的冷水级分和角叉菜的40％乙醇级分中还含有少量L-卡拉胶。IR谱图也表明,在1250;850和805cm~(-1)有k-和L-卡拉胶所特有的吸收谱带。以1250,850和805cm~(-1)对2920cm~(-1)的吸收面积比值估算了硫酸基的相对含量。 相似文献
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以κ-卡拉胶(硫酸基含量25.1％,分子质量83.1 kD)为原料,研究了二甲基亚砜-甲醇法(DMSO法)、三甲基氯硅烷法(CTMS法)以及苯并四甲酸-三氧化二锑法(PMA法)对其脱硫后多糖样品的得率、硫酸基含量及分子质量的影响.结果表明,κ-卡拉胶经三种方法脱硫后,样品得率分别为45.3％、50.6％和62.0％,脱硫率分别为42.2％、48.6％和82.8％,分子质量分别为15.7、22.3和4.75 kD.通过红外光谱和硫酸基含量分析表明,PMA法脱硫效果优于DMSO和CTMS法.PMA法不仅对κ-卡拉胶有效,而且适合于l-卡拉胶、λ-卡拉胶和岩藻聚糖硫酸酯的脱硫. 相似文献
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海洋细菌QY202产κ-卡拉胶酶的分离纯化和性质研究 总被引：1，自引：0，他引：1
为获得高效降解卡拉胶菌株,从青岛太平角海域采集的角叉菜表面分离到1株高产κ-卡拉胶酶的海洋交替假单胞菌(Pseudoalteromonas sp.)QY202,经硫酸铵沉淀、脱盐、DEAE阴离子交换层析等步骤从该菌株发酵液上清中分离纯化得到1种专一性降解κ-卡拉胶的κ-卡拉胶酶,并研究了该酶的基本酶学性质.结果表明该酶被纯化了23.1倍,回收率为43.9%,分子量大小为33.2 kDa.酶的最适反应温度为40 ℃,最适反应pH为8.0,在0～40 ℃,pH=7.0～8.0之间酶活力较稳定.酶对底物κ-卡拉胶的米氏常数Km值为1.6 mg/mL.Na~+、K~+对酶活有促进作用,而Hg~(2+)、Cu~(2+)强烈抑制酶的活性.酶解κ-卡拉胶的主产物为硫酸新κ-卡拉二糖和硫酸新κ-卡拉四糖. 相似文献
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Erminio Murano Renato Toffanin Ester Cecere Roberto Rizzo Svein Halvor Knutsen 《Marine Chemistry》1997,58(3-4)
Dried samples of the red algae Solieria filiformis and Agardhiella subulata from Mar Piccolo, Taranto, were extracted by stirring in water at 25 (Cold), 85 (Hot) and 120 (pressure) °C. For each species, six successive cold, three hot and two pressure extractions were performed and analyzed separately. Water-soluble polysaccharides were isolated after treatment with amylase, alcohol precipitation, dialysis and freeze drying. The total, starch-free yields were 27 and 24% of the dry weight for S. filiformis (SF) and A. subulata (AS), respectively. FTIR and NMR spectroscopic analysis showed that the different cold and hot water extracts had a similar structural backbone, which can be characteristic of gelling type carrageenans with a dominant iota repeating structure (DA2S-G4S). However, some irregularities were detected by NMR, which may be attributed to 6-sulphated 4-linked precursor units. The occurrence of such and other irregularities was more frequent in the SF samples, giving a possible explanation for the enhanced extractability in cold water of carrageenan polymers from this species. 相似文献
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《Marine Chemistry》2000,71(3-4)
Massive mucilage events occur in the Northern Adriatic Sea presumably by cytoplasmic excretions from deteriorated diatoms. During three such events in the summer of 1991, 1997 and 1998 the presence of reduced sulfur species (RSS) was determined in samples of macroaggregate using electrochemical methods (in-phase alternating current (AC) and linear sweep voltammetry). The detected levels of sulfur, expressed as equivalent to sulfide concentrations, were about 200 nM. In the same mucilage samples, concentrations of organic matter were determined in the range from 60 to 600 mg/l of total organic carbon (TOC). The physico-chemical properties of organic matter in the macroaggregates correspond to those of polysaccharides of very high molecular mass. Scanning confocal laser microscopy (SCLM) and fluorescent molecular probes for sugars (the lectins concanvaline A (Con-A)) showed the transformation of polysaccharide polymer structure resulting in the formation of very stable filaments and layers after the treatment of mucilage samples with sodium sulfide. Commercial polysaccharides of bacterial and algal origin (xanthan, carrageenans types I and II, dextran-T-500) have been used to simulate macroaggregate formation under laboratory conditions after treatment with sodium sulfide. Raman spectroscopy indicated that for all model polysaccharides used, sulfide interaction occurred, as evidenced by visible change of the O–H stretching region in the vibration spectra of the water molecules.Our data suggest that the aggregated polysaccharides from the Adriatic Sea are: (1) structurally affected by addition of sulfide as was the case for most of the model polysaccharides, and (2) the stabilizing effect of sulfide on the aggregated polysaccharides is due to the formation of sulfur-organic compounds. 相似文献
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Salvador E. Lluch-Cota Eugenio A. Aragón-Noriega David Aurioles-Gamboa Richard C. Brusca Roberto Cortés-Altamirano Alfonso Esquivel-Herrera Michel E. Hendrickx Hugo Herrera-Cervantes Miguel Lavín Daniel B. Lluch-Cota Silvio G. Marinone Sofia Ortega-García Alejandro Parés-Sierra Mauricio Ramírez-Rodríguez Richard A. Schwartzlose Arturo P. Sierra-Beltrán 《Progress in Oceanography》2007,73(1):1-26
The Gulf of California is unique because of its geographical location and conformation. It hosts diverse ecosystems and important fisheries that support industry and provide livelihood to coastal settlements. It is also the site of interests and problems, and an intense interaction among managers, producers, and conservationists. In this report, we scrutinize the abiotic (hydrography, climate, ocean circulation, and chemistry) and biotic (phyto- and zooplankton, fish, invertebrates, marine mammals, birds, and turtles) components of the marine ecosystem, and some particular aspects of climate variability, endemisms, harmful algal blooms, oxygen minimum layer, and pollution. We also review the current conditions and conflicts around the main fisheries (shrimp, small and large pelagic fishes, squid, artisanal and sportfishing), the most important human activity in the Gulf of California. We cover some aspects of management and conservation of fisheries, especially the claimed overexploitation of fish resources and the ecosystems, and review proposals for creating networks of marine protected areas. We conclude by identifying main needs for information and research, particularly the integration of data bases, the implementation of models and paleoreconstructions, establishment of monitoring programs, and the evaluation of fishing impacts and management actions. 相似文献
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As the global trade and market for seafood has grown, so have the twin problems of renaming and mislabeling. Resource scarcity, the potential for greater profits, and weak legislation have all encouraged incorrect labeling, the results of which include consumer losses, the subversion of eco-marketing, further degradation of fisheries resources, and even adverse effects on human health. This paper examines the extent and consequences of renaming and mislabeling seafood, the state of current legislation, and the importance of future policies, with particular attention to the US, where 80% of the seafood is imported and more than one-third of all fish are mislabeled. Policy recommendations include governments’ support for a global mandate to label species, country of origin, and catching or production method on all seafood with high penalties for infractions. Chain of custody standards, such as those recently implemented by the Marine Stewardship Council (MSC), should also be considered for adoption worldwide. To garner support for this legislation, consumers must become better acquainted and concerned with their seafood and its origins. 相似文献
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Environment and Deep-Sea Mining: A Perspective 总被引：1，自引：0，他引：1
As the quest for deep-sea mineral resources is gaining momentum, environment and ocean mining have become important aspects of study. Because many of these deposits occur in international waters, the concern for environmental conservation in view of the effects of deep-sea mining is resulting in these effects being studied in different oceans, and efforts to develop regulations governing this exploitation are also underway at national and international levels. The impact assessment of deep-sea mining needs to encompass a variety of subjects, including environmental, socioeconomic, technological, and legal aspects. At the same time, effects of in situ environmental conditions on mining activities also need to be considered for effecient performance by the mining system. Differences in the degree of impact have been noticed during the mining simulation experiments by different investigating agencies. Therefore, interparameter comparisons, standardization of methods, and improvement in mining design are important considerations for proper utilization of resources, conservation of environment, and cost efficiency of the mining operations. 相似文献
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海草床可以为海洋动物提供产卵、索饵、繁育等场所。目前, 海草床面积急剧下降, 其中我国关于虾形草属(Phyllospadix)海草的研究相对较少, 对于虾形草主要繁育载体种子的描述、显微观察和萌发过程方面存在较多空白。本研究以红纤维虾形草(Phyllospadix iwatensis)为研究对象, 对其生长环境、种子外部特征、内部结构、萌发过程等进行了定性定量描述。结果表明, 虾形草果实种子对于海洋环境有着外部形态与内部结构的适应性, 外部形态特点包括独特的果序和果实形状, 以及翅状结构和内侧鬃毛, 其中果序呈弯虾形, 平均长度3.4cm, 果实呈马掌形, 直径3~4mm, 内部结构特征包括胚乳占比大、果皮种皮解剖结构复杂等, 具有作为海岸带植被修复工具种的优势。本研究补充了目前对虾形草等海洋沉水植物种子的研究资料, 为虾形草海草种质库保护与海草床修复提供了建议和参考。 相似文献
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养殖文蛤体内寄生的一种吸虫幼虫及宿主组织病理学 总被引：3，自引：0，他引：3
作为文蛤吸虫病害研究的基础资料，报道了寄生在文蛤体内的1种复殖吸虫幼虫的形态结构及宿主由此所产生的组织病理学变化。研究表明：该吸虫分别为咆蚴和尾蚴。咆蚴圆筒形，内含不同发育阶段的尾蚴。成熟尾蚴体成扁平舌状，具有口吸盘、腹吸盘，1对眼点和1条细长无刺的尾巴。该吸虫主要侵占生殖腺，少部分幼虫进入附近的消化盲囊、鳃、肾等部位。轻微感染者，生殖滤泡萎缩，生殖细胞发育滞后；严重感染的宿主，生殖腺完全被侵占并耗尽。消化盲囊、鳃、肾等器官组织也因幼虫感染呈现不同程度的病理学变化；严重者上皮细胞水肿或脱落，肌肉组织结构紊乱或溶解等。本工作同时显示，吸虫寄生可诱发宿主血淋巴细胞大量增生，并产生凝集、组织浸润及形成包囊等免疫反应。 相似文献
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Les Watling Robert H. Findlay Lawrence M. Mayer Daniel F. Schick 《Journal of Sea Research》2001,46(3-4)
Scallops are usually obtained by means of a heavy metal dredge that is pulled over the sea bottom. Most studies of the impact of this gear type have shown that larger invertebrates, in particular, are severely disturbed. These studies, however, have been conducted on coarse sediments, ranging from sands to cobble, and have dealt only with faunal changes. In this paper the impact of a New England type scallop dredge on the fauna and sedimentary nutritional characteristics of a silty sand community is detailed. The site, in the Damariscotta River, Maine, USA, was sampled during the fall and winter prior to, then again immediately following, the dragging event, and twice more over the ensuing six months. Loss of surficial sediment, lowered food quality of the sediment (as measured by microbial populations, enzyme hydrolysable amino acids, and chlorophyll a), and changes in the faunal composition of the dragged site were observed. While some taxa returned to the drag track relatively quickly, others such as the cumaceans, phoxocephalid and photid amphipods, and nephtyid polychaetes, were not seen in abundances comparable to those of the adjacent undragged site until the food quality also recovered. 相似文献
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重力测量系统中测量的重力,即重力加速度,是一种特殊的加速度,因而重力传感器是一种特殊的加速度计。在动态场合,现代重力仪一般采用基于陀螺仪构建的各种平台为重力传感器提供姿态基准。因此采用加速度计和陀螺仪这些惯性元件的动态重力测量系统可以看做是惯性技术的一种具体应用。从惯性技术的角度对动态重力测量的理论和现状进行了分析。首先介绍了在地球表面附近进行重力测量时涉及的参考坐标系。然后详细推导了动态重力测量的基本理论,即比力测量理论,指出比力方程是动态重力测量和惯性导航的共同基础。最后对不同载体对动态重力测量系统的影响与要求进行了分析。 相似文献