海带褐藻糖胶的研究

本工作研究了我国人工养殖的海带叶片中褐藻糖的分布，及海带综合利用工业的废料碱凝沉物中褐藻糖胶的存在量和分离条件。海带叶片中的褐藻糖含量分布边缘比中部多，并从基部向尖部增加，即由0．3％增至1％以上。试验了用十六烷氯化吡啶法(CPC法)和乙醇沉淀法从碱凝沉物中分离褐藻糖胶的条件。两种方法的褐藻糖胶获得率分别为5．6％和4．4％(对干碱凝沉物)，其中的褐藻糖含量分别为24．7％和28．7％。碱凝沉物中的褐藻糖含量为1．4～3．5％。还研究了从褐藻糖胶以酸水解制取褐藻糖的诸条件，并分离出纸层析纯的褐藻糖结晶。     

利用褐藻酸钠生产污水提取褐藻糖胶

从海带综合利用生产褐藻酸钠、碘、甘露醇后的污水中提取褐藻糖胶的实验条件研究表明：Na2CO3溶液与污染 水用量比（体积比）为1：5.5，pH为5.5，乙醇浓度为60％，复水温度为75℃时，提取的粗褐藻糖胶中褐藻糖的质量百分比浓度最大达到22.5%，粘度测定结果证明本法制得的褐藻糖胶与干海带直接提取的褐藻糖胶的性质是相似的。     

铜藻的褐藻糖胶、褐藻淀粉和褐藻胶的分离及提纯

本文研究了从铜藻中分离提取褐藻糖胶、褐藻淀粉和褐藻胶的方法。用稀盐酸溶液加温搅拌提取藻粉后，在提取液中含有褐藻糖胶和褐藻淀粉，可加乙醇至50％和80％分别将其沉淀出来。藻渣含有褐藻酸钠，可加温加碱而制备出。并用正交实验设计求出提取条件中的温度、pH和时间的最适配比。对于褐藻糖胶的提取，以温度70℃、时间2小时和提取液pH为4时最适。对于褐藻淀粉的提取，以温度70℃、时间1小时和提取液的pH为2时较优。本文还对粗褐藻糖胶和褐藻淀粉的提纯进行了研究，证明二者均可用酒精分级沉淀法处理而得到纯品，不需要采用较复杂的季胺盐法和离子交换树脂法。本工作证实铜藻是我国褐藻中含有三种多糖的较好藻种，从中可提褐藻糖胶3．5%，褐藻淀粉3．1％和褐藻酸钠17．8％。     

裙带菜褐藻糖胶的分离及部分理化性质研究

以裙带菜为原材料,采用水提法从裙带菜中分离褐藻糖胶,Sevag法去蛋白,乙醇分步沉淀法进行初步纯化。试验结果表明,裙带菜褐藻糖胶的最适提取温度为80℃,时间为8 h,加水量为1∶30,在最适条件下的提取率为1.72%,蛋白质含量为5.44%。对褐藻糖胶部分理化性质亦进行了研究,其特性黏度为5 mpa.s,pH为8.50,含有硫酸基。     

羊栖菜浮筏栽培技术初步探讨

羊栖菜(sargassumfusiforme)是一种多年生的暖温带大型褐藻,俗你“海麦子”,富含聚胶糖等多种人体必需的微量元素,营养价值高、口感好、味道鲜美,为海藻中的上等营养佳品,素有“海上人参”之称,具有巨大的市场潜力。连江海域前些年虽有群众开展羊栖菜栽培,但未能取得理想的栽培     

应用中空纤维超滤膜分离纯化甘露醇

采用中空纤维超滤膜分离技术对海带中提取的甘露醇进行纯化精制，以去除其中的褐藻糖胶和低分子褐藻胶等有机杂质。经应用自行设计的超滤装置对天然甘露醇进行纯化，取得了良好的效果，产品质量明显提高，且每吨甘露醇成本仅增加103元，显著地提高了该产品在国内外市场上的竞争能力。     

变废为宝 铸造胶研制成功

国内褐藻工业传统的方法是将废渣同其它废水一起排放掉,造成严重的环境污染。中国科学院海洋研究所和南京工学院、南京汽车厂铸造厂合作,对褐藻胶残渣的用途进行了反复的试验研究,确定了利用褐藻胶残渣生产铸造胶的工艺条件,研制成功H S—3型铸造胶,并成功地应用于含     

我国裙带菜人工育苗技术研究进展

<正>裙带菜(Undaria pinnatifida)是温带性一年生大型褐藻,在生物学分类系统上属褐藻门、褐子纲、海带目、翅藻科、裙带菜属,是中国三大经济海藻之一[1-2]。裙带菜营养物质含量丰富,包括多种氨基酸和维生素,还含有人体必需的不饱和脂肪酸,其营养和保健功能也越来越引起人们重视。裙带菜富含褐藻糖和碘,可用来降血脂和预防甲状腺肿。此外,裙带菜也是提取褐藻胶的重要原料[3]。裙带菜是北太平洋特有种,自然分布在中国、     

低分子褐藻聚糖硫酸酯寡糖的研究进展

正褐藻聚糖硫酸酯又称岩藻聚糖,主要来源于褐藻、海参和海胆等生物。不同来源的褐藻聚糖硫酸酯结构因来源不同而存在差异、且较复杂。即使同一特定褐藻中的褐藻聚糖硫酸酯也可能存在不同的结构~([1])。近些年来褐藻聚糖硫酸酯的大部分结构及其骨架已经被逐渐揭示~([2]);随着结构的揭示其功效或构效研究逐渐增多。     

开发褐藻废渣在罗非鱼饵料中的利用

开发褐藻废渣在罗非鱼饵料中的利用我国褐藻工业以海带与马尾藻为原料，主要生产褐藻胶、甘露醇和碘。经过多年不断改造和调整，目前已形成布局相对集中，具有相当规模和我国特色的行业结构，产量已居世界前列。褐藻蛋白是褐藻工业生产原料的重要成分，至今尚未得到合理利...     

大窑湾牡蛎养殖区叶绿素a分布和初级生产力估算

根据1997年4－12月间对大窑湾牡蛎湾牡蛎养殖区的生态环境调查结果，讨论了该养殖水域叶绿素a含量分布特征和季节变化，对初级生产力进行估算。结果表明，大窑湾浮筏养殖区叶绿素a含量上于较低水平，平均为1．02mg/m^3。叶绿素a含量分布呈现出明显的季节差异，秋季较高。初级生产力的分布与叶绿素a含量分布存在差异，丰季最高，海水透明度可能是造成这种差异的重要影响因子。     

星突江鲽精子的超微结构

应用扫描电镜和透射电镜观察了星突江鲽Platichthysstellatus精子的超微结构。星突江鲽的精子由头部、中段和尾部组成。头部呈球形，主要结构为细胞核。核前端无顶体，后端有植入窝，植入窝较浅，凹入深度约为细胞核直径的I／4。核中染色质致密，但存在染色质较浅的头部凹陷和核泡。中段包括中心粒复合体和袖套。近端中心粒的长轴与基体的长轴相互垂直，呈“T”字型排列，基体的长轴与精子的长轴平行。袖套很浅，其最深处只达到线粒体下端的1／3处。在袖套线粒体的外面，具有大量的椭圆形囊泡存在。尾部细长，主要由轴丝构成，为典型的“9＋2”微管结构。鞭毛较粗，长有两排侧鳍，侧鳍不对称。鞭毛细胞质中可见大小不一的椭圆形囊泡存在，囊泡的分布不均匀，一侧囊泡数量较多，另一侧偏少。鞭毛的这种结构与精子的运动相适应。     

Use of individual types of fishing effort in analyzing catch and effort data by use of a generalized linear model

Fishing effort is a function of many (continuous) variables which fishers can manipulate. However, when catch and fishing effort data are analysed using a generalized linear model, individual types of fishing effort usually enter as a composite quantity. But not all quantities can be combined into a composite quantity. Use of such data this way generally leads to a loss of information and incurs a model bias. In this paper, I analyse catch and effort data for the blue swimmer crab off South Australia by a direct use of individual types of fishing effort to extract a relative index of biomass, and use the concept of homogeneous functions to present some of the results. I also give formulae for choosing a combination of different types of fishing effort to effect a specified level of catch in both absolute and relative terms. Assuming that catch follows an independent gamma, normal, negative binomial, or Poisson distribution, fitting of a generalized linear model with a log-link function to the commercial catch and effort data suggests that: (1) the exploitable biomass remained relatively constant from 1 July 1983 to 30 June 1996; (2) the relative instantaneous rate of fishing mortality of a particular sex and age (if gear selectivity was constant over time) slightly increased over time; (3) a 1% increase in the number of days fished gave about 0.85% increase in catch whereas a 1% increase in the number of people on a boat led to only about a 0.45% increase in catch. This implies that use of a composite measure of fishing effort such as boat days and man days when analysing catch and effort data is inappropriate for this fishery. Although a generalized linear model may be a reasonable first-order approximation, catch and effort data are best interpreted through a process model.     

Effect of Addition of Different Acetic Acid Concentrations on the Quality of Marinated Herring

This study investigated the effect of acetic acid concentrations from 3 to 8% on the physicochemical and sensory quality of marinated Atlantic and Baltic herring from fresh and frozen-thawed material. The increased concentration of acetic acid was found to exert a strong impact on decreased sensory scores, weight yield, and pH value as well as on an increased brightness parameter of meat. In turn, moisture, protein hydrolysis products (PHB), total volatile bases (TVB) content, and hardness parameter were affected by the higher addition of acid to a lesser extent. Enhanced protein hydrolysis was observed only at acetic acid concentration of 5% or 5–8%, whereas there was a decrease in the content of TVB only at an acid concentration of up to 4–5%. The marinated frozen-thawed fillets, compared to the fresh ones, required a greater addition of acid in the brine, by 1.5%, to reach a similar pH value. The freezing of fish contributed also to a decrease of PHB and free hydroxyproline, along with an increased concentration of acetic acid. The marinades from frozen-thawed herring contained more TVB, had worse color, and hardness parameters, as well as less yield.     

Processing and bioactivity of the corpuscles of Stannius protein of the Australian eel

The primary structure of the major protein from the Corpuscles of Stannius (CS) of the Australian eel was elucidated from the cDNA sequence and was found to bear close similarity to the N-terminal amino acid sequence of the presumably homologous salmon hormone, teleocalcin (TC). The cDNA sequence predicted a preproprotein of 263 amino acids. Following removal of a 17 amino acid signal peptide, specific monobasic cleavage at an Arg-Phe bond generates the 231 amino acid mature form of the protein. The isolation and sequence determination of the prosequence confirms that the precursor contains a prosegment of 15 residues. Various fragments of the protein have been synthesized chemically and their biological activity assessed. The N-terminal 1–20 fragment of the mature protein inhibits calcium uptake in fingerling trout, the effect being similar, but not equipotent to salmon teleocalcin. Further, infusion of either the N-terminal 1–20 or the 81–94 fragment at 50 μg/h into the renal artery of conscious sheep, caused significant decreases in systemic plasma potassium concentration and in potassium excretion. The 1–20 fragment also gave rise to a small but significant increase in sodium excretion. Infusion of TC at the same rate results in a significant decrease in plasma potassium and phosphate concentration as well as a significant decrease in potassium excretion. Bovine PTH (1–34) at 100 μg/h causes a small decrease in plasma potassium and phosphate and an increase in plasma calcium concentration, and was the only peptide to cause a significant decrease in calcium excretion.     

Evaluation of the influence of different species and cultivars of lupin kernel meal on the extrusion process, pellet properties and viscosity parameters of salmonid feeds

This study examined the influence of different lupin species and cultivars and their inclusion levels on the physical properties of an extruded diet. Lupin kernel meals were included into a fish diet formulation at 0%, 10%, 20% and 30%. Soybean meal was also included in a series of diets on a similar basis as a reference. The diet mashes were extruded using a laboratory-scale APV19:45 twin-screw extruder. The pellets were examined for radial expansion, bulk density, vacuum oil uptakes, sink rate, shear and crush strengths. Inclusion of lupin kernel meal significantly increased bulk density, sink rate, shear and crush strength of the pellets. With the increase in lupin kernel meal inclusion level, a concomitant decline in vacuum oil uptake and radial expansion was also observed. An assessment of the diet mashes using a Rapid Visco Analyser showed that the inclusion of lupin kernel meals increased the rate and degree of gelatinization of the mash starch content compared with that with a similar inclusion level of soybean meal. The inclusion of lupin kernel meals in the diet mash also improved the water-holding capacity of the extrudate, which has important implications for the reduction in extruder wear.     

The role of the lethal extracellular cytolysin of Aeromonas salmonicida in the pathology of furunculosis

Abstract. The histopathological effects of intramuscular (i.m.) and intraperitoneal injections of the purified lethal cytolytic toxin of A. salmonicida in Atlantic salmon, Salmo salar L., were restricted to extensive degranulation of eosinophilic granular cells (EGCs) in the gills (both routes) and a limited coagulative necrosis of muscle fibres at the site of i.m. injection. The severity of these lesions did not apparently differ amongst fish that were moribund within 48 h and the surviving fish at 90 h. Previous studies indicate a maximum time to death caused by this toxin of 48 h. Thus, it is difficult to account for death of the fish from the toxin solely on the grounds of the histopathological features. It is suggested that a complex metabolic dysfunction results in death. The mechanism of 'furuncle' formation was demonstrated to result from a combined effect of the cytolysin and the purified 70-kDa protease present in the ECP. When i.m.-injected singly, the purified cytolysin produced a limited coagulative necrosis and the purified protease produced a limited liquefaction and haemorrhaging. In combination, they induced the extensive liquefactive haemorrhagic 'furuncle' characteristic of the whole ECP.     

二种微生物制剂对青虾池水质和生长的影响

将二种微生物制剂施用于青虾养殖池,观察池塘水质的变化和对青虾规格及产量的影响,结果表明,施用微生物制剂后,池水的溶解氧、总磷增加,氨氮值下降,而COD、pH和总氮则没有明显变化和差异。试验池青虾的生长速度明显要大于对照池,说明微生物制剂可明显改善水环境,提高养殖青虾的产量和规格。     

The impact of repeat spawning of males on effective number of breeders in hatchery operations

In conservation hatcheries, typically a great emphasis is placed on maximizing the effective number of breeders through spawning an appropriate number of spawners, spawning equal numbers of males and females when possible, and by mating either in a single-pair or factorial fashion. A commonly encountered problem, especially in small operations with anadromous salmonids, is a shortage of males at some point during the season, so that some males need to be spawned multiple times. This has an impact on the genetically effective number of breeders, and the commonly used equations for effective number are not applicable. In this paper I derive a relatively simple equation for effective number of breeders when some males are multiply spawned but reproductive contribution within spawning classes are equal: , where i is the number of times a male is spawned, N_i the number of males spawned i times, and μ_t the mean gametic contribution. I also derive an equation that allows relaxation of the assumption of equal contribution within classes. I then develop a number of simple and accurate approximations for the effective number of breeders. The equations can be applied to any situation in which there are discrete spawning classes in which the average reproductive contribution of any one class can be expressed as a multiple of that of another class.     

Assessment of methods for the determination of digestibilities of feed ingredients for Tra catfish,Pangasinodon hypothalamus

In this study, we undertook a series of experiments to assess different faecal‐collection methods and also the digestibilities of a range of feed ingredients when fed to Tra catfish (Pangasinodon hypothalamus). Apparent digestibility coefficients for dry matter, energy and nitrogen for a reference diet were also determined from faeces collected by way of settlement at 2‐h intervals from 2 to 24 h. No significant effect of sample collection time on the digestibility values was observed. Stripping was attempted, but was not considered a suitable method for collecting digesta from Tra catfish. Dissection collection was also evaluated. Values determined from dissection collection were lower than those from using settlement. In a second experiment, a suite of test ingredients was combined with a reference diet component in a 30 : 70 ratio to determine the ingredients for dry matter, energy and nitrogen digestibilities. Ingredients included were trash‐fish, defatted rice bran, wet full‐fat rice bran, dried full‐fat rice bran, broken rice, cassava, soybean and fish meals. Collection of faeces by settlement was used for determining the digestibility of each of the ingredients. The results showed that Tra catfish can efficiently digest protein and energy from a wide range of feed ingredients and nutrient sources.