聚β-羟基丁酸酯来源及其在水产养殖中的应用

聚β-羟基丁酸酯(poly-β-hydroxyalkanoates,PHB)是发现最早的一种聚羟基链烷酸酯(polyhydroxyalkanoate,PHA),属于聚酯类化合物。1925年法国学者Lemoigne首次在巨大芽孢杆菌(Bacillus megaterium)细胞中发现分离并提取出了聚β-羟基丁酸酯[1]。聚β-羟基丁酸酯具有热塑性、组织亲和性、光学活性、生物可降解性和生物相容性等多种优良特性,同时还可利用再生资源进行生物合成,在工业、环保、医药等领域有广泛应用[2]。有研究表明,聚β-羟基丁酸酯常在营养不均衡的条件下作为微生物细胞中能量和碳的来源[3]。     

后期坛紫菜提取琼胶的工艺探讨

琼胶(Agar)，又称琼脂、冻粉、燕菜，是由石花菜、江蓠、伊谷草或凝花菜等某些红藻加水煮沸提取出的一种极有经济价值的多糖。其主要组成是琼胶糖、丙酮酸琼胶糖和硫酸半乳糖等3种产物组成的混合物，而琼胶糖是一种中性线型多糖，系1，3-结合的β-D-吡喃半乳糖单元与1，4-结合的3，6-脱水-α-L-吡喃半乳糖残基所成的链状结构。     

单糖组合对藤壶金星幼虫附着的影响研究

藤壶Amphibalanus(=Balanus)amphitrite是典型的海洋污损生物,藤壶金星幼虫受外源信号的指引,寻找到合适的附着地点才能进行附着和变态。针对前期发现的有一定诱导活性的4种单糖Man、Xyl、Glc和Fuc,该研究利用正交试验研究其对藤壶金星幼虫附着的影响。结果发现,单糖组合对藤壶金星幼虫附着具有显著性影响,Man(5.00×10^-8 mol/L)、Glc(1.25×10^-8 mol/L)、Xyl(1.25×10^-8 mol/L)和Fuc(1.90×10^-7 mol/L)为最优组合。组合中4种单糖的影响力由高到低依次是Man>Fuc>Glc>Xyl,且Man、Fuc和Glc的影响具有显著性,Xyl对幼虫附着影响不大。添加单糖除了影响金星幼虫的附着率以外,更重要的是能显著缩短幼虫附着的时间进程。     

日本对虾血清凝集素的基本物理化学性质

日本对虾（Penaeus japonicus)亲虾体长19-24.5cm，取其血清。7种动物血液取自大白鼠、小白鼠、豚鼠、兔、鸡、羊、人。结果表明：（1）虾血清分别在28、37、56℃时热处理30min，其凝集活性不变，在70℃和80℃热处理30min后凝集活性完全丧失。（2）血清在pH和5-7.5的TBS缓冲液中凝集活性稳定，在pH为8-9之间凝集活性迅速下降。（3）凝集抑制实验表明半乳糖、甘露糖、L-阿拉伯糖、D-葡萄糖胺、N-乙酰-D-葡萄糖胺等5种糖对血清凝集素都有较强的抑制作用，尤其D-葡萄糖胺和N-乙酰-D-葡萄糖胺的抑制作用更强。（4）交叉吸附实验结果显示日本对虾血清对大白鼠、小白鼠的红细胞有较强的亲和性。     

菹草石油醚组分中抑藻活性物质的分离纯化和抑藻活性

菹草石油醚组分能显著抑制赤潮微藻米氏凯伦藻的生长,为了获悉该组分抑制米氏凯伦藻的物质基础,采用硅胶柱层析和制备薄层层析等方法,对菹草石油醚组分中的抑藻活性物质进行分离纯化。进一步应用质谱、核磁共振碳谱和氢谱等技术,鉴定抑藻活性物质。实验从菹草石油醚组分中分离纯化到4种抑藻活性物质。当浓度为16μg/m L时,它们对米氏凯伦藻表现出一定的抑藻活性。结构鉴定表明,此4种抑藻活性物质分别为二十五烷醇、邻苯二甲酸二(2-甲基己基)酯、棕榈酸和邻苯二甲酸二(5,5-甲基己基)酯。此4种化合物为首次从菹草中分离得到。抑藻活性分析表明,当浓度为50μg/m L时,4个样品均能显著抑制赤潮异弯藻的生长。其中,二十五烷醇和邻苯二甲酸二(5,5-甲基己基)酯还能较明显地抑制东海原甲藻和球形棕囊藻的生长。     

二甲亚砜对中国鲎NAGase的抑制作用

节肢动物的周期性蜕皮与N-乙酰-β-D-氨基葡萄糖苷酶(EC3.2.1.52,NAGase)密切相关。从中国鲎内脏分离提取N-乙酰-β-D-氨基葡萄糖苷酶，利用酶抑制作用动力学方法研究二甲亚砜对中国鲎N-乙酰-β-D-氨基葡萄糖苷酶的影响。试验结果显示：二甲亚砜对中国鲎N-乙酰-β-D-氨基葡萄糖苷酶有较强的抑制作用，0.1 mol/L二甲亚砜可使酶活性下降38.0%,该抑制作用为可逆过程；动力学研究显示，二甲亚砜对N-乙酰-β-D-氨基葡萄糖苷酶的抑制作用是属于竞争性-非竞争性混合型抑制，二甲亚砜对游离酶(E)的抑制常数(K_I)和对酶-底物络合物(ES)的抑制常数(K_IS)分别为0.200 mol/L和1.063 mol/L,K_IIS,表明底物对N-乙酰-β-D-氨基葡萄糖苷酶在二甲亚砜溶剂中的失活具有保护作用，随着底物浓度增大，二甲亚砜对酶的失活作用降低；酶蛋白的紫外吸收光谱和内源荧光发射光谱显示，随着二甲亚砜溶剂浓度升高，N-乙酰-β-D-氨基葡萄糖苷酶酶蛋白紫外吸收值亦在升高，但其...     

渤海石油平台污损生物生态研究

2013年9月-2014年9月在渤海海域进行了污损生物挂板试验,共记录污损生物24种,以温带种和广温种为主,优势种是多棘麦秆虫(Caprella acanthogaster)、日本大螯蜚(Grandidierellajaponica)、理石叶钩虾(Jassa marmorata)、拟钩虾(Gammaropsis sp.)等.季板分析结果显示,表层季板的平均生物量为1764.23 g/m2,中层季板的平均生物量为2322.31 g/m2.试验海域全年均有污损生物附着,但种类和附着量季节性差异明显,污损生物附着盛期为夏季和秋季.污损生物群落Shannon-Wiener多样性指数(H')和Margalef丰富度指数(d)秋季最高.多元统计分析表明,污损生物群落按时间可分为3个群落类型,反映出渤海海域污损生物群落的季节变化明显.相关性分析显示,表层和中层试板污损生物的生物量与水温具有显著的相关性,相关系数分别为0.959和0.986(P＜0.01).     

免疫多糖的理化特性及其对水产动物免疫系统的作用机理

免疫多糖(immune folysacchride)通常是指能决定疫苗抗原特异性的部分,这种物质广泛地分布于真菌、细菌和植物体内.如β-葡聚糖(βglucan)不仅是构筑多种生物细胞壁的材料,而且在生物间相互影响的过程中也显示出各种免疫生物学活性.近年来,为了避免各种渔用化学药物在水产养殖动物体内的残留和对养殖水环境的污染问题,从各种生物中提取的免疫多糖类物质作为产业开发的重要对象而倍受关注.迄今为止,对从真菌中提取的β-葡聚糖结构的研究已经有较多报道.     

纵条矶海葵低极性成分及其油脂的降血脂活性研究

对一种污损生物纵条矶海葵进行了低极性成分及其油脂的降血脂活性研究。首次从纵条矶海葵的低极性部位中分离得到△4,5-(E),△8,9-(E)-鞘氨醇-正十六碳酰胺与胆甾醇两个化合物。对纵条矶海葵油的脂肪酸组成分析表明,该海葵油中富含高不饱和脂肪酸EPA与DHA,总相对含量达61.9%;降血脂活性实验表明,纵条矶海葵油高剂量组可明显降低实验大鼠血管内TC、TG、HDL-C含量,具有较好的降血脂活性。开展对纵条矶海葵油脂的加工工艺研究,将有望获得新的高不饱和脂肪酸来源,进而开发出新的具降血脂功能的海洋药品或保健食品。     

植酸酶和NSP酶在蛋鸡日粮中的应用研究进展(二)

2 NSP酶在蛋鸡日粮的应用研究进展 2.1 NSP的抗营养作用 谷物多糖从化学上主要分为两种类型:贮存多糖和结构多糖结构多糖常称为NSP,是植物组织中由多种单糖和糖醛酸经糖苷键连接而成、大多有分支的链状结构,常与无机离子和蛋白质结合在一起,是细胞壁的主要成分,一般难于被单胃动物自身分泌的消化酶所分解.Bailey(1973)根据结构特点把NSP分类成3个主要部分,即纤维素(β-1,4-葡萄糖的直链聚合物)、非纤维素(阿拉伯木聚糖,β-葡聚糖,甘露聚糖)多糖、果胶多糖(明根@朝格图等,1996).     

3种重金属对瓦氏黄颡鱼的急性毒性试验

在室内常温静水条件下,采用氯化镉、硫酸铜、硝酸亚汞3种重金属盐类对瓦氏黄颡鱼进行了毒性试验。试验结果表明,3种药物的毒性强弱依次为:硝酸亚汞>硫酸铜>氯化镉。安全质量浓度分别为:硝酸亚汞0.0036 mg/L、硫酸铜0.1501 mg/L、氯化镉8.6372 mg/L。     

异源铜盐对仿刺参幼参急性毒性及组织形态学影响

采用急性毒性试验方法研究异源铜盐对仿刺参（Apostichopus japonicus）幼参的毒性影响,通过24h、48h、72h和96h的致死数量统计分析硫酸铜（CuSO4）/氯化铜（CuCl2）对幼参的半致死质量浓度（LC50）和安全质量浓度（SC）;利用石蜡切片显微定性观察不同铜盐对刺参幼参后肠的毒性情况。结果表明,CuSO4来源的Cu^2＋对幼参24h、48h和72h的LC50均大于CuCl2来源的Cu^2＋对幼参24h、48h和72h的LC50,而CuCl2对幼参96h LC50大于CuSO4对幼参96hLC50;异源铜盐在暴露前48h内对刺参的毒性影响极其显著,随着暴露时间的延长其对刺参的毒性影响不显著;2种铜盐（以铜离子质量浓度为0.06 mg·L^-1计）对幼参的消化道均有不同程度的腐蚀作用,导致结缔层与上皮层分离,CuCl2对刺参肠道的毒性（类似腐蚀作用）大于CuSO4的毒性;不同的阴离子对Cu^2＋的毒性有拮抗作用。     

Amino acid availability and protein digestibility of several protein sources for Nile tilapia,Oreochromis niloticus

Apparent amino acid availability coefficients and protein digestibility of four animal products [fish meal (FM), meat and bone meal (MBM), poultry by‐product and feather meal] and four plant protein‐rich products [soybean meal (SBM), cottonseed meal‐28, cottonseed meal‐38 and corn gluten meal (CGM)] were determined for Nile tilapia, Oreochromis niloticus. Ingredients were incorporated to a practical reference diet at a 7 : 3 ratio (70% of reference diet and 30% of test ingredient). Chromic oxide was used as external digestibility marker. Among animal products poultry by‐product meal (PBM; 89.7%) and FM (88.6%) presented the highest apparent protein digestibility (APD) while MBM (78.4%) and feather meal (78.5%) presented the lowest APD. Among plant protein‐rich products CGM (91.4%) and SBM (92.4%) presented the highest APD values while cottonseed meal‐28 presented the lowest APD (78.6%). Average apparent amino acid availability of feed ingredients was similar to protein digestibility with 92.3%, 89.6%, 73.4%, 80.7%, 88.9%, 84.4%, 91.2% and 79.7% values for SBM, CGM, cottonseed meal‐28 and 38, FM, MBM, PBM and feather meal respectively. These results indicate that O. niloticus is able to utilize efficiently different feedstuffs.     

硫酸铜和高锰酸钾对似刺鳊鮈幼鱼的急性毒性试验

室温条件下,用静水生物测试法,分别用硫酸铜和高锰酸钾对似刺鳊鮈幼鱼的进行急性毒性试验。结果显示,硫酸铜和高锰酸钾对似刺鳊鮈幼鱼24h的LC50值分别为0.6148mg/L和1.5987mg/L;48h的LC50值分别为0.5517mg/L和1.1637mg/L;72h的LC50值分别为0.4950mg/L和0.9906mg/L;96h的LC50值分别为0.4698mg/L和0.9828mg/L。硫酸铜和高锰酸钾对似刺鳊鮈幼鱼的安全浓度分别为0.04698mg/L和0.09828mg/L。似刺鳊鮈幼鱼对硫酸铜和高锰酸钾的耐受力:高锰酸钾>硫酸铜。似刺鳊鮈人工养殖疾病防治过程中,硫酸铜和高锰酸钾消毒药液须慎用。     

Isolation of antifouling substances from the Palauan sponge Protophlitaspongia aga

ABSTRACT: Fouling organisms cause serious problems by settling on ships' hulls, and other marine infrastructures. Organotin compounds have been developed as effective antifoulants. However, environmental problems are associated with these compounds. It is necessary to find antifouling substances that exhibit a lower toxicity than those substances currently used. A new pyrimidine derivative, 3,4,5,6-tetrahydro-6-hydroxymethyl-3,6-dimethyl-4-pyrimidinecarboxylic acid, (compound 1) and zooanemonin (compound 2) were isolated from the marine sponge Protophlitaspongia aga as antifouling substances against the barnacle Balanus amphitrite . We also found that α-nicotinamide ribose (compound 3) inhibited germination and the attachment of Ulva spores.     

Essential fatty acid deficiency in freshwater fish: the effects of linoleic, α-linolenic, γ-linolenic and stearidonic acids on the metabolism of [1-14C]18:3n-3 in a carp cell culture model

The desaturation of [1-¹⁴C]18:3n-3 to 20:5n-3 and 22:6n-3 is enhanced in an essential fatty acid deficient cell line (EPC-EFAD) in comparison with the parent cell line (EPC) from carp. In the present study, the effects of competing, unlabeled C₁₈ polyunsaturated fatty acids (PUFA), linoleic (18:2n-6), -linolenic (18:3n-3), -linolenic (18:3n-6) and stearidonic (18:4n-3) acids, on the metabolism of [1-¹⁴C]18:3n-3 were investigated in EPC-EFAD cells in comparison with EPC cells. The incorporation of [1-¹⁴C]18:3n-3 in both cell lines was significantly reduced by competing C₁₈ PUFA, with the rank order being 18:4n-3>18:3n-3 = 18:2n-6>18:3n-6. In the absence of competing PUFA, radioactivity from [1-¹⁴C]18:3n-3 in EPC cells was predominantly recovered in phosphatidylethanolamine followed by phosphatidylcholine. This pattern was unaffected by competing n-6PUFA, but n-3PUFA reversed this pattern as did essential fatty acid deficiency in the presence of all competing PUFA. The altered lipid class distribution was most pronounced in cells supplemented with 18:4n-3. Competing C₁₈ PUFA significantly decreased the proportions of radioactivity recovered in 22:6n-3, pentaene and tetraene products, with the proportions of radioactivity recovered in 18:3n-3 and 20:3n-3 increased, in both cell lines. However, the inhibitory effect of competing C₁₈ PUFA on the desaturation of [1-¹⁴C]18:3n-3 was significantly greater in EPC-EFAD cells. The magnitude of the inhibitory effects of C₁₈ PUFA on [1-¹⁴C]18:3n-3 desaturation was dependent upon the specific fatty acid with the rank order being 18:4n-3>18:3n-3>18:2n-6, with 18:3n-6 having little inhibitory effect on the metabolism of [1-¹⁴C]18:3n-3 in EPC cells. The differential effects of the C₁₈ PUFA on [1-¹⁴C]18:3n-3 metabolism were consistent with mass competition in combination with increased desaturation activity in EPC-EFAD cells and the known substrate fatty acid specificities of desaturase enzymes. However, the mechanism underpinning the greater efficacy with which the unlabeled C₁₈PUFA competed with [1-¹⁴C]18:3n-3 in the desaturation pathway in EPC-EFAD cells was unclear.     

Effect of in vitro xenoestrogens on steroidogenesis in mature female fish, Chasmichthys dolichognathus

In this study, fully vitellogenic oocytes of the longchin goby (Chasmichthys dolichognathus) were exposed to in vitro xenoestrogens such as diethylstilbestrol (DES), bisphenol A (BPA) and nonylphenol (NP) at concentrations of 100 ng/ml in the presence of [³H]17α-hydroxyprogesterone as precursor. The major metabolites produced in vitro are progestogens [17α-hydroxy,20α-dihydroprogesterone (17α20αOHP) and 17α-hydroxy,20β-dihydroprogesterone (17α20βOHP)], androgens [androstenedione (A4) and testosterone (T)] and estrogens [estrone (E1) and estradiol-17β (E2)]. Comparative activities of these chemicals in oocyte steroid biosynthesis showed as follows: NP treatment resulted in clear stimulation of estrogen production, while the opposite occurred in DES treated incubation. Treatment with DES resulted in a higher synthesis of 17α20αOHP. BPA treatment increased the androgen, while estrogen synthesis was slightly inhibited. These results suggest that NP exhibited clearly estrogenic activity on the three chemicals.     

Cu↑（2+）对黄鳝肝脏保护酶SOD、CAT、GSH-PX活性的影响

以肝脏组织保护酶SOD，CAT，GSH－PX活性为指标研究了CuSO4污染对黄鳝的损伤作用，实验测得CuSO4对黄鳝的LC50为5．5mg/L，据此设定CuSO4浓度梯度，结果表明，0．7，1．5mg/L的CuSO4处理液对黄鳝的损伤较小，3．0，4．5mg/L的CuSO4处理液对黄鳝损伤较大，保护酶SOD，CAT，GSH－PX的活性在黄鳝暴露24h时被显著抑制，在处理48h后酶活性逐渐恢复并超过对照组水平，之后又回落到低于对照组水平，其变化幅度与CuSO4质量浓度呈正相关，可以证实，SOD，CAT，GSH－PX活性变化可以反映黄鳝的伤害程度。     

11种常用渔药对淡水硝化细菌硝化作用的影响

在硝化作用稳定的试验系统中加人常用剂量的戊二醛0.5mg/L(全水体质量浓度,下同)、高锰酸钾3mg/L、聚维酮碘2mg/L、生石灰20mg/L,溴氯海因1 mg/L、漂白粉2mg/L、敌百虫1mg/L、指环净0.6mg/L、CuSO_4 0.5mg/L+FeSO_4 0.2mg/L合剂、氟苯尼考6mg/L和土霉素20...     

Effects of dietary borage oil [enriched in γ-linolenic acid,18:3(n-6)] or marine fish oil [enriched in eicosapentaenoic acid,20:5(n-3)] on growth,mortalities, liver histopathology and lipid composition of juvenile turbot (Scophthalmus maximus)

A marine fish oil, Marinol K (MO) and borage oil (BO) were used to formulate diets relatively rich in eicosapentaenoic acid [EPA; 20:5(n-3)] and -linolenic acid [GLA; 18:3(n-6)], respectively. The diets were fed to duplicate groups of juvenile turbot (Scophthalmus maximus) of initial weight 1.4 g for a period of 12 weeks. No differences were observed in final weights either between duplicate tanks or between dietary treatments. Mortalities in the MO-fed group were significantly greater than in the BO-fed group. In the MO-fed group, 7 out of 12 fish sampled for histological analysis showed a pronounced liver histopathology whereas only 1 of 12 fish sampled in the BO-fed group showed slight pathology. EPA levels were increased 2.2-fold and its elongation product, 22:5(n-3), was increased 1.8-fold while arachidonic acid [AA; 20:4(n-6)] was decreased by 30% in MO-fed fish compared to the initial carcass composition. GLA was increased 53-fold and its elongation product dihomo--linolenic acid [DHGLA; 20:3(n-6)] was increased 16-fold while AA was reduced by 90% in BO-fed fish compared to the initial carcass composition. The amount of triacylglycerol in liver of BO-fed fish was significantly greater than levels in MO-fed fish. The fatty acid compositions of individual phospholipids from liver showed marked differences between dietary treatments. Fish fed MO had significantly higher levels of the (n-3) polyunsaturated fatty acids (PUFA), 20:5(n-3), 22:5(n-3) and 22:6(n-3), and also significantly more 20:4(n-6) compared to BO-fed fish which had significantly higher 18:2(n-6), 18:3(n-6), 20:2(n-6) and 20:3(n-6). The composition of liver phosphatidylinositol was particularly unusual in BO-fed fish having DHGLA as the major C₂₀ PUFA which was 2.2-fold greater than AA and 3.9-fold greater than EPA. This study demonstrates that the carcass composition of turbot can be altered, by means of dietary lipids, to contain increased levels of EPA and DHGLA which would be of potential benefit in human as well as in fish nutrition. However, caution should be exercised when using very highly unsaturated oils relatively rich in EPA which may generate histopathological lesions in the fish.Abbreviations AA arachidonic acid - ANOVA analysis of variance - BHT butylated hydroxytoluene - BO borage oil - DHA docosahexaenoic acid - DHGLA dihomo--linolenic acid - EPA eicosapentaenoic acid - GLA -linolenic acid - HPTLC high performance thin-layer chromatography - MO Marinol K - PC phosphatidylcholine - PE phosphatidylethanolamine - PI phosphatidylinositol - PS phosphatidylserine - PUFA polyunsaturated fatty acid - TLC thin-layer chromatography