三疣梭子蟹消化酶的初步研究

开发研制配合饲料,以酶学分析方法研究了温度、pH对三疣梭子蟹(Portunus trituberculatus)中肠腺3种主要消化酶(蛋白酶、淀粉酶和纤维素酶)活性的影响及消化酶(蛋白酶、胰蛋白酶、胰凝乳蛋白酶、羧肽酶A、羧肽酶B、淀粉酶、脂肪酶和纤维素酶)在胃、中肠腺、肠道中的活性分布。结果表明:蛋白酶、淀粉酶、纤维素酶的最适温度分别为55℃,55℃,65℃;蛋白酶、淀粉酶、纤维素酶的最适pH分别为7~8,7.5,4.8;蛋白酶、淀粉酶、纤维素酶在短时间内有很高的热稳定性及很广的酸碱稳定性范围。蛋白酶、胰蛋白酶、羧肽酶A、羧肽酶B活性均以中肠腺最高,胃和肠道中没有测出胰凝乳蛋白酶活性;淀粉酶活性在胃、中肠腺、肠道中差别不大;纤维素酶和脂肪酶活性在胃和肠道高于中肠腺。     

温度和pH值对南美白对虾(Penaeus vannmei)消化酶活性的影响

采用双因子交互的方法研究了不同温度和pH值对南美白对虾淀粉酶、蛋白酶和脂肪酶活性的影响。结果表明，南美白对虾肝脏、肠道、胃的淀粉酶最适温度分别为30℃、35℃、30—35℃，最适pH均为6．2。肝脏、肠道、胃的蛋白酶最适温度分别为50—65℃、55—65℃、60℃，肝脏蛋白酶最适pH为8．5—9．0，肠道蛋白酶最适pH为7．5—8．5，胃蛋白酶最适pH为2．0和5．5—6．5。脂肪酶的活力很小，肝脏、肠道、胃的脂肪酶最适温度均为37℃ ，最适pH均为7．7。同时测得南美白对虾肠道、肝脏、胃组织内的pH分别为6．7—7．0、5．9—6．1、5．1—5．3。在三种消化酶各自最适的温度、pH值下，比较其活力大小，在肝脏、肠道、胃均为蛋白酶>淀粉酶>脂肪酶。     

温度和pH值对南美白对虾(Penaeus vannmei)消化酶活性的影响

采用双因子交互的方法研究了不同温度和pH值对南美白对虾淀粉酶、蛋白酶和脂肪酶活性的影响。结果表明 ,南美白对虾肝脏、肠道、胃的淀粉酶最适温度分别为 30℃、35℃、30— 35℃ ,最适pH均为 6 2。肝脏、肠道、胃的蛋白酶最适温度分别为 5 0— 65℃、5 5— 65℃、60℃ ,肝脏蛋白酶最适pH为 8 5— 9 0 ,肠道蛋白酶最适pH为 7 5— 8 5 ,胃蛋白酶最适pH为2 0和 5 5— 6 5。脂肪酶的活力很小 ,肝脏、肠道、胃的脂肪酶最适温度均为 37℃ ,最适pH均为 7 7。同时测得南美白对虾肠道、肝脏、胃组织内的pH分别为 6 7— 7 0、5 9— 6 1、5 1—5 3。在三种消化酶各自最适的温度、pH值下 ,比较其活力大小 ,在肝脏、肠道、胃均为蛋白酶>淀粉酶 >脂肪酶。     

温度和pH对条石鲷幼鱼消化酶活力的影响

研究了温度和pH对条石鲷Oplegnathus fasciatus幼鱼胃、肠、肝内3种主要消化酶(蛋白酶、淀粉酶和脂肪酶)活力的影响.结果表明,1)肠和肝的蛋白酶最适温度均为25℃,而胃蛋白酶最适温度为28℃;胃和肝淀粉酶最适温度是22℃,肠淀粉酶的最适温度为19℃;各消化器官的脂肪酶在16℃时活力最高.当温度在16-28℃之间时,条石鲷幼鱼的脂肪酶和蛋白酶活力较高,淀粉酶活力较低.2)胃蛋白酶最适pH为3.2,淀粉酶最适pH是7.6,脂肪酶最适pH为4.2;肠蛋白酶、淀粉酶和脂肪酶最适pH分别是8.6、6.6和6.6;肝蛋白酶最适pH是7.6,肝淀粉酶和脂肪酶最适pH均为6.6.     

大黄鱼(Pseudosciaena crocea)消化道不同部位两种消化酶的活力分布及其受温度、pH的影响

采用改变离体条件下大黄鱼消化道不同器官消化酶的作用温度和pH的方法,对其不同消化器官中的蛋白酶和淀粉酶活力进行测定,研究两种消化酶活力的分布特征以及温度、pH对两种消化酶活力的影响。结果表明,在消化道生理酸碱条件下蛋白酶活力胃>后肠>前肠>肝胰脏(P<0.01);淀粉酶活力肝胰脏、胃>后肠>前肠(P<0.01);在实验设定的条件范围内,胃、肝胰脏、前肠、后肠各部位蛋白酶的最适温度分别为35℃、30℃、40℃、35℃,淀粉酶的最适温度分别为30℃、25℃、30℃、35℃。随着温度由低向高变化,两种酶各部位活力均有从低向高然后逐渐降低的变化趋势;蛋白酶的最适pH值分别为2.2、6.0、7.0、8.0,淀粉酶各部位最适pH值分别为3.9、7.0、7.0、7.0。在设定的实验pH范围内,胃蛋白酶的活力随着pH值的升高而迅速降低,其余各部位酶均有随pH升高酶活力先升而后降的变化趋势。     

温度对不同规格欧鳗消化器官蛋白酶和淀粉酶活性影响的初步研究

本试验设置的8个反应温度组为5℃，15℃，20℃，25℃，30℃，35℃，45℃和55℃，欧鳗分51．5～57．5g，92．5～99．5g，128．5～136g，226～233g4种规格，试验结果表明，蛋白酶活性在4种规格均表现为肠＞胃＞肝，并均随温度升高而增强。在45℃蛋白酶活性最强，其中51．5～57．5g规格组肠蛋白酶活性显著较高．淀粉酶活性，基本上随着温度升高活力升高，温度在25℃时活性最高，以后其活性又开始下降。肝、肠、胃淀粉酶活性在两种较小规格下，胃＞肠＞肝，在较大规格，肝＞肠＞胃。     

温度和盐度对半滑舌鳎幼鱼消化酶活性的影响

以半滑舌鳎(Cynoglossus semilaevis Günther)幼鱼为实验对象,分别设置3个盐度水平(22、26和30)和4个温度水平(18,21,24和27 ℃),采用酶活性分析的方法比较研究了在不同温度和盐度的养殖环境下,半滑舌鳎肝胰脏和肠道内不同部位蛋白酶、淀粉酶和脂肪酶3种消化酶活性的差异.结果表明,盐度和温度对半滑舌鳎消化酶活性影响均显著 (P<0.05).不同温度和盐度组合下,3种消化酶活性变化有所差异.总体比较,肝胰脏和肠道内3种消化酶比活力均以盐度26、温度21和24 ℃组合下活性较高.在相同温度和盐度下,肝胰脏和肠道的不同部位的3种消化酶活性有所差异,其中,蛋白酶比活力以肝胰脏和后肠最高,显著高于前肠和中肠(P<0.05);淀粉酶比活力以肝胰脏内最高,各肠段之间淀粉酶比活力差异不显著(P>0.05);淀粉酶比活力也以肝胰脏内最高,其次分别为前肠、后肠和中肠,各部位脂肪酶比活力差异显著(P>0.05).本研究发现半滑舌鳎幼鱼体内淀粉酶比活力相对比较高,说明半滑舌鳎幼鱼对淀粉具有较强的消化能力,建议在配制半滑舌鳎幼鱼饲料时可适当提高淀粉比例,以降低饲料成本.     

牙鲆体内消化酶活性的研究

采用生化方法对一年龄牙鲆胃、肠中不同消化酶的活性进行了研究。实验组I的牙鲆平均体重为 ( 35 0± 2 0 )g ,实验组II的牙鲆平均体重为 ( 4 60± 30 )g。结果表明 ,在牙鲆的胃、前肠、中肠、后肠中可以检测出蛋白酶、脂肪酶、淀粉酶的活性。胃中的蛋白酶主要为酸性蛋白酶 ,肠中的蛋白酶主要为碱性蛋白酶。肠中蛋白酶活性由前肠向后肠递减 ,前肠与中肠的酶活性没有显著差异 (P >0 .0 5 ) ;牙鲆肠中脂肪酶活性较胃中的高 ,在肠的不同部位脂肪酶的活性无显著差异 (P >0 .0 5 ) ;牙鲆前肠中的淀粉酶活性最高 ,胃次之 ,中肠、后肠中淀粉酶活性较低。随着牙鲆的生长 ,蛋白酶、脂肪酶活性增强 ,淀粉酶活性减弱。对产生上述实验结果的原因进行了初步分析。     

温度和pH对刺参(Apostichopus japonicus)消化酶活力的影响

消化酶活力能够反映刺参对不同营养成分的消化能力。当某一反应条件发生改变时,消化酶的活力大小就会发生变化,因此研究不同因子对消化酶活力的影响对于了解消化酶的性质具有重要的意义。温度和pH是影响消化酶活力的最重要的反应条件。本文中作者应用酶学分析研究了温度和pH对剌参前肠和中肠各种消化酶活力的影响。蛋白酶活力测定采用福林-酚法,脂肪酶活力测定采用水解法,淀粉酶活力和纤维素酶活力测定采用水杨酸显色法。实验结果表明,反应温度和反应pH对刺参前肠和中肠中的消化酶活力具有显著影响(P<0.05)。前肠和中肠中蛋白酶活力均在反应温度为50℃时达到最大值,前肠和中肠中脂肪酶和纤维素酶均在反应温度为40℃时达到最大值,而前肠和中肠中淀粉酶最适反应温度分别为40℃和30℃。刺参前肠蛋白酶活力在酸性环境下较中肠高,且在反应pH为5.0—5.8之间酶活力相对稳定,而中肠蛋白酶活力在碱性环境下较前肠高,且在反应pH为7.0—8.6之间酶活力相对稳定;刺参前肠脂肪酶活力随着pH的升高出现两个相对稳定的峰值,分别为4.2—5.0和6.2—7.0区间,中肠脂肪酶活力在pH为3.8时达到最大值,而在pH超过9.0明显失活:剌参前肠和中肠淀粉酶活力在pH变化时表现出相似的变化趋势,在反应pH为6.6—7.4之间酶活力较高且相对稳定;剌参前肠和中肠中纤维素酶活力在pH变化时反应不一致,前肠淀粉酶在反应pH为6.2—7.4之间酶活力较高且相对稳定,中肠纤维素酶活力在反应pH为5.4—7.0之间酶活力较高且相对稳定。此外,通过比较四种消化酶比活力值的大小,可以看出剌参蛋白酶活力最高,其次为纤维素酶和淀粉酶活力,而脂肪酶活力最低。     

pH和温度对小荚蛏淀粉酶和纤维素酶活性的影响

研究了pH和温度对小荚蛏淀粉酶和纤维素酶活性的影响.结果表明:pH和温度对淀粉酶和纤维素酶活性的影响差异显著;当温度在5～75℃之间,小荚蛏淀粉酶的最适温度为35～45℃,纤维素酶的最适温度为45℃;在不同的pH条件下,淀粉酶的最适pH为5.6～6.2,纤维素酶的最适pH为4.2～4.6.实验测定结果表明小荚蛏的淀粉酶活性远高于纤维素酶活性.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

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.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

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.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

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.     

《Acta Oceanologica Sinica》Vol. 33(2014) contents

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INFORMATION FOR AUTHORS

<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,