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％。     

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。     

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、     

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。     

褐藻糖胶的提取纯化方法

褐藻糖胶是存在于褐藻中的硫酸酯多糖，具有多种生物活性。本文综述了褐藻糖胶的提取、纯化和分级等方面的研究工作。     

裙带菜的加工制作方法

裙带菜为褐藻类海带科的海草,主要分布在日本及朝鲜半岛的海域。干的裙带菜含水分15～18%、蛋白质10～16%、脂质1～2%、糖质38～45%(其中藻酸20%)、纤维素2～3%、灰分18～30%。另外,     

出口盐渍裙带菜的加工技术

<正> 裙带菜俗称“海芥菜”,由于它的外形很象裙带,因而被称为裙带菜。裙带菜属于褐藻门,翅藻科,是一种温带性褐藻,我国主要产于北方沿海一带。裙带菜营养丰富,口味鲜美,是一种经济价值较高的海味食品。它的营养成份:粗蛋白含量为11.20%,粗脂肪含量为0.32%,碳水化合物含量为37.80%,灰份为18.93%,水份为31.35%。灰份中含有多种矿物质,藻体内含有多种维生素,对人体的生长十分有利。裙带菜的含碘量丰富,因而常食裙带菜,能预防甲状     

对裙带菜生产未来的展望

一、日本裙带菜的生产和发展裙带莱很早是在日本与南朝鲜海域自然生长的一种褐藻。1954年时大槻洋四郎在宫城县女川湾开始裙带菜的养殖试验。裙带菜在日本沿海分布很广。在南方有鹿     

裙带菜及其养殖技术

裙带菜是一种褐藻,属于裙带菜属,除北海道的东南部和东北部外的所有日本沿岸均有分布。由于历来裙带菜销售价格比紫菜低,所以在日本是一种重要的食料,裙带菜以鲜的或干的形式销售,特别是用于大豆酱汤内作配料的数量增多,它经常作为日本家庭的早餐菜。     

世界裙带菜养殖概况

裙带菜是一种重要的食用褐藻，有较高的经济价值。中国，日本，韩国和法国是裙带菜的主要生产国。其中韩国产量高，年产约２８万ｔ。日本消费量阳大，年消费约２０万ｔ。     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.