虾蛄肉酶法制备抗氧化肽的工艺优化和活性研究

以虾蛄(Oratosquillaoratoria)肉为研究的对象,用胰蛋白酶水解得到抗氧化肽,以1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率为指标,采用L16(45)正交试验和三因素三水平的响应面分析法,对酶解工艺进行分析优化。结果表明最佳的酶解工艺条件为:温度51.1°C,pH7.07,加酶量1500U/g,料液比1︰3.09,酶解时间2h,DPPH自由基清除率47.3466%,理论值与预测值相差很小,说明该方法可行。在此条件下测得羟基自由基的清除率为88.9%,超氧阴离子清除率为29.13%,还原力A700为0.243,表明虾蛄肉酶解多肽有较强的抗氧化性,可以进一步分离纯化从中提取抗氧化肽。     

南美白对虾副产物酶解工艺优化及其蛋白肽活性评价

为高质化利用南美白对虾加工副产物蛋白资源,本研究以南美白对虾加工副产物虾头虾壳为原料,蛋白水解度为考察指标,采用单因素和响应面试验优化酶解工艺。检测虾蛋白肽分子量的分布范围,评价其抗氧化能力及免疫调节作用。结果表明,碱性蛋白酶与虾头内源酶自溶酶解具有较好的协同作用,最佳酶解工艺参数值为：酶添加量4%、酶解时间6.5 h、酶解温度40 ℃、料液比1∶5。经蛋白层析仪检测,分子质量分布在75~1 355 Da的蛋白肽占比达到76.35%。虾蛋白肽的羟自由基清除率IC₅₀为4.64 mg/mL、DPPH自由基清除率IC₅₀为3.08 mg/mL,提示其具有一定的抗氧化能力。虾蛋白肽中剂量组（10 mg/kg）能显著促进淋巴细胞增殖,并提高免疫低下模型小鼠的免疫器官指数和吞噬指数,表明虾蛋白肽具有显著的免疫调节作用。     

响应面法优化罗非鱼(Oreochromis niloticus)鱼排蛋白分段酶解工艺

采用生物蛋白酶酶解罗非鱼鱼排蛋白,以水解度(DH)为指标,进行了单酶、复合酶酶解效果的比较分析,并利用响应面分析方法(RSM)对酶解参数进行优化。结果表明,采用风味蛋白酶和木瓜蛋白酶双酶组合分段酶解,固定总酶添加量为3.0%、双酶复合比2:1、酶解时间3h、分段酶解时间比0.6:1,酶解温度56℃,分段酶解pH为7.0和6.2时,酶解效果最佳,罗非鱼鱼排蛋白水解度达到32.49%,酶解产物中游离氨基酸含量达32.84mg/g鱼排,占罗非鱼鱼排总氨基酸含量的25.43%,其中呈味氨基酸含量达18.48%,必需氨基酸含量达67.96%。     

响应面法优化酶法制备藻蓝蛋白抗氧化肽的实验研究

为优化碱性蛋白酶酶解藻蓝蛋白制备抗氧化肽的工艺条件,采用响应面分析法,以超氧阴离子自由基清除率为响应值,研究了[E]/[S]、酶解温度和时间对制备抗氧化肽工艺的影响.结果表明,制备藻蓝蛋白肽的最佳酶解条件为:温度为44.9℃、时间为6.4 h和[E]/[S]为3.6%,此时对超氧阴离子自由基清除率达到75.39%.在该条件下制备的藻蓝蛋白酶解产物(0.5 g/L)还原能力的吸光度为1.03,并达到稳定.     

酶解糙刺参内脏团蛋白制备抗氧化肽的工艺研究

为了能够有效利用糙刺参内脏蛋白,以水解度为主要指标,对酶解蛋白酶进行了筛选,并系统研究了酶解温度、p H、加酶量和水解时间等单因素对水解度的影响。在此基础上,利用响应面中心组合设计实验,对酶解工艺进行了优化,得到以温度、p H、加酶量及水解时间为因子的二次方程,通过方差分析和验证性实验得出,此二次方程能较好反应海参内脏团蛋白水解度的变化规律,得到最佳水解条件为:温度52.66℃,p H 6.71,加酶量2.5%(质量分数),酶解时间10 h,预测最高水解度为49.58%。最佳酶解条件下所得多肽74%以上分子质量小于500 Da。利用DPPH法测定最佳条件酶解所得多肽的抗氧化活性,3 g/L的抗氧化率达到了24.8%,利用ABTS法测定最佳条件酶解所得多肽的抗氧化活性,3 g/L的抗氧化率达到了0.255μmol/g。为海参内脏蛋白的利用提供了参考。     

基于UF、GFC及RP-HPLC的长牡蛎(Crassostrea gigas)蛋白抗衰老小分子活性肽(Zel'ner)的纯化及结构解析

牡蛎肉质鲜美,营养丰富,具有很高的食用价值。本研究以舟山长牡蛎(Crassostreagigas)为研究对象,以DPPH自由基清除率为测试指标,通过UF、GFC及RP-HPLC等技术,对牡蛎蛋白酶解液进行分离纯化,获得牡蛎蛋白小分子肽样品,并对其氨基酸组成进行营养性评价。研究结果表明:浓度为30%—100%的硫酸铵处理酶解液的分离效果明显优于低于浓度为30%硫酸铵的分离效果,其DPPH自由基清除率达到52.43%;纯化后得到两种牡蛎蛋白小分子肽分别标记为组分a(Mw1kDa)和组分b(1kDaMw3kDa);组分a中牡蛎蛋白小分子肽分子量分布主要为1995.2Da、1258.9Da、1023.3Da、398.1Da;对牡蛎蛋白小分子肽组分a进行检测,发现其中氨基酸种类及含量丰富,其中必需氨基酸(EAA)含量为18.863%,总氨基酸含量(TAA)为43.3748%,必需氨基酸占总氨基酸43.49%,必需氨基酸与非必需氨基酸(NEAA)的比例为76.95%,风味氨基酸(FAA)含量为18.9147%,占总氨基酸含量的43.61%。综上可见,牡蛎蛋白小分子肽具有极高的营养价值和市场经济效益,此研究为牡蛎蛋白抗衰老小分子活性肽(Zel'ner)的开发提供了新的思路和方向。     

响应面法优化热泉菌Bacillus sp.Lc50-1的发酵产卡拉胶酶条件

采用响应面法对1株高产卡拉胶酶的印度尼西亚热泉菌Bacillus sp.Lc50-1的发酵条件进行优化。分别以培养温度、pH值、C源、N源、金属离子及接种量作为唯一变量进行单因素实验,筛选出对酶活有显著影响的单因素取值范围;参考单因素实验结果,再利用Box-Behnken设计及响应面分析法进行回归分析以确定最佳发酵条件。结果表明,培养温度、卡拉胶浓度(C源)、蛋白胨浓度(N源)、KCl浓度(金属离子)与酶活存在着显著的相关性,通过求解回归方程得到Bacillus sp.Lc50-1的最佳发酵条件为:培养温度47.5℃、蛋白胨0.25%、卡拉胶0.3%、KCl 21.55mmol·L-1,优化后发酵上清液的酶活达到8.9U·mL-1,比优化前提高了1.5倍。     

基于Gibbs抽样的贝叶斯方法估计大菱鲆生长和耐高温性状的遗传参数

为了开展大菱鲆耐高温选育工作，对其进行耐高温性状及其相关生长性状的遗传评估是非常必要的。以来源于英国、法国、丹麦和挪威4个国家的不同群体构建大菱鲆选育家系，利用F₁的20个和F₂的22个耐高温选育家系进行耐高温实验，统计耐高温评估指标（UTT）和相应的实验鱼体重（每个家系选取40-50尾实验鱼）。基于Gibbs抽样的贝叶斯方法，采用包含母性效应和不包含母性效应的两种动物模型，对大菱鲆耐高温（UTT）和生长性状的遗传力以及这两个性状间的遗传相关和表型相关进行分析。结果表明，基于不包含母性效应的动物模型估计的体重和耐高温性状的遗传力以及这两个性状之间的表型相关和遗传相关分别为0.239±0.141,0.111±0.080,0.075±0.026和-0.019±0.011。基于包含母性效应的动物模型估计的这4个值分别为0.203±0.115,0.055±0.026,0.047±0.034和-0.024±0.028,体重和耐高温性状的母性效应分别为0.050±0.017和0.013±0.004。母性效应对这两个性状的遗传评估有一定的影响。本文的研究结论为制订合理的大菱鲆耐高温育种规划提供了理论依据。     

富油微藻富碳培养下油脂积累及固碳研究

微藻固碳是一种新型节能减排技术，具有长期可持续发展的潜力。本文对两株富油微藻（球等鞭金藻和微拟球藻）进行了富碳培养下生长特性及中性脂积累特性的研究。两株富油微藻的最佳培养条件为10%CO₂浓度和f培养基。本研究对两株富油微藻的最大生物量产率、总脂含量、最大油脂产率、微藻的C含量和CO₂固定率进行了测定。球等鞭金藻的各参数指标分别为：142.42±4.58g/（m²·d），39.95%±0.77%，84.47±1.56g/（m²·d），45.98%±1.75%和33.74±1.65g/（m²·d）。微拟球藻的各参数指标分别为：149.92±1.80g/（m²·d），37.91%±0.58%，89.90±1.98g/（m²·d），46.88%±2.01%和34.08±1.32g/（m²·d）。实验结果显示，两株海洋微藻均属于高固碳优良藻株，适合应用于微藻烟气减排技术开发，具备用于海洋生物质能耦合CO₂减排开发的潜力。     

Characteristic analysis on oxygen isotopic tracer in the East China Sea and waters to east of the Ryūkyū-guntō

Samples of O isotopic tracer were mlleMed at Sections P₃,P₂₅,P_cM-t/2-E and P_CM-1/2.w in both the Fast China Sea and the area to the east of the Ryūkyū-gunto during October-November,1991.Analytical results of the δ¹⁸O are as follows: (1) In the Kuroshio area,the δ¹⁸O isolines are almost parallel to the 200 m isobath.The value of δ¹⁸O is negative and reaches minimum mt the main axis of the Kuroshio,and increases on both sides.(2) In the Taiwan Warm Current (TWC) area there is a high δ¹⁸O tongue extending to the northeast.(3) In the area near the coast,the distribution of δ¹⁸O isoline shows that the Changjiang River runoff diffuses seaward and the land-ocean isotopic effect from the nearshore to the offshore.(4) The values of δ¹⁸O are from -1.0×10^-3 to -0.5×10^-3 in the shelf.(5) There is a low mre of δ¹⁸O value(<-1.6×10^-3) at the 600 m layer in the Kuroshio area,which is quite in accord with the existence of a low salinity mre (S G 34.30) between the 600 and 800 m layers in the same area.Finally,the mrrelations of the δ¹⁸O with the salinity and temperature,the upwelling and so on are discussed.     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

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.     

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.     

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。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

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.     

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

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