海带、裙带菜和龙须菜凝集素提取及其性质研究

采用0.9%生理盐水、PBS(pH=7.2的磷酸盐缓冲液)和0.9%生理盐水+PBS的混合液3种提取液,提取海带、裙带菜和龙须菜凝集素,探究其凝集活性、蛋白浓度和比活力。结果表明:0.9%生理盐水提取海带凝集素的凝集活性、比活力皆最大,分别为0.062 U/μg(产生凝集现象的最小凝集素量)和16258.16 U/mg;0.9%生理盐水提取裙带菜凝集素的蛋白浓度最大,为14.98 mg/mL,海带次之。综合分析认为,不同提取液对海藻凝集素的凝集活性、蛋白浓度、比活力影响显著,0.9%生理盐水提取海藻凝集素效果较优。

Evaluation of nutritive value and in vitro rumen fermentation gas accumulation of de-oiled algal residues

Background：Algae are widely recognized for their high oil content and for exponentially accumulating biomass with particular potential to provide single cell protein for human consumption or animal feed.It is believed that along with biodiesel from algae,the high protein de-oiled algal residue may become an alternative feed supplement option in the future.This study was conducted to investigate de-oiled algal residue obtained from the common Chlorella species,Thalassiosira weissflogii,Selenarstrum capricornutum,Scenedesmus sp.,and Scenedesmus dimorphus for assessment as potential feed supplements for ruminants by comparing with soybean（Glycine max） meal and alfalfa（Medicago sativa） hay.Results：With the exception of T.weissflogii,algal residue had higher concentrations of Cu,Zn,and Mn and lower concentration of Ca,Mg,and K than soybean meal and alfalfa hay.The algal residue CP（crude protein）concentrations ranged from 140 to 445 g/kg DM and varied among the de-oiled residues.In vitro rumen fermentation gas accumulation curves indicated that algal biomass degradation potential was less than that of soybean meal or alfalfa hay by up to 41.7%.The gas production curve,interpreted with a dual pool logistic model,confirmed that the fraction sizes for fast fermenting and slow fermenting of de-oiled algal residues were smaller than those in soybean meal and alfalfa hay,and the fermenting rate of the fractions was also low.Conclusions：Inferior in vitro rumen gas accumulation from the five de-oiled algal residues suggests that these algal byproducts are less degradable in the rumen.

Selected dietary plant-based proteins for growth and health response of Nile tilapia Oreochromis niloticus

Tilapia culture is one of the largest sectors of global aquaculture.Among the different species of tilapia,Nile tilapia(Oreochromis niloticus)is perhaps the top cultured species.The production of Nile tilapia has been continually increasing throughout the years resulting in genetic deterioration.Several tilapia strains with better growth performance and adaptive capability to survive in different culture conditions have been developed to alleviate the crisis.Increased demand for Nile tilapia implies higher farming cost.Plant-based proteins are utilized as partial or complete fishmeal replacements to reduce feed cost.However,these proteins can adversely affect and alter growth and feed performance,carcass composition and indices,and gut and hepatic health.This review discusses the use of seven plant-based proteins:namely,soybean,copra,pea,corn,palm kernel,microalgae,and seaweed as a Nile tilapia aquafeed.Different processing methods are employed to produce several types of plant-based proteins.Processed plant-protein types,when utilized as an aquafeed ingredient,vary in its effect on the performance,hemato-immunological parameters,and gut and hepatic health of Nile tilapia.Studies have shown that Nile tilapia can effectively maximize plant-based protein diets based on the preparation method,type of plant source,amino acid supplementation,and inclusion levels of the plant proteins.These readily available crops should be considered as primary protein sources for aquaculture.Hindrances to the use of plant-based proteins as a main dietary protein are limiting amino acids,presence of anti-nutritional factors,and the competition between its demand as human food and as animal feed.

罗非鱼-大豆共沉淀蛋白乳液稳定二十二碳六烯酸藻油的研究

为探究共沉淀蛋白乳液稳定二十二碳六烯酸(docosahexenoic acid,DHA)藻油的可行性,该研究以罗非鱼分离蛋白(tilapia protein isolate,TPI)、3种罗非鱼-大豆共沉淀蛋白(tilapia-soy protein co-precipitates,TSPC_(2∶1)、TSPC_(1∶1)和TSPC_(1∶2))和大豆分离蛋白(soy protein isolate,SPI)为乳化剂,高压均质制备TPI、TSPC和SPI-DHA藻油乳液,比较5种乳液的物理稳定性和氧化稳定性。结果表明,与TPI乳液比较,随着原料中大豆比例的增加,TSPC-DHA藻油乳液的平均粒径和乳析指数减小(P<0.05),Zeta电位绝对值增大(P<0.05),乳液的物理稳定性增强。与SPI乳液比较,贮藏过程中TSPC-DHA藻油乳液的过氧化值和硫代巴比妥酸反应物值明显较小(P<0.05),乳液的氧化稳定性明显改善。TSPC_(1∶1)和TSPC_(1∶2)乳液在4℃贮藏28 d无明显分层,氧化产物含量接近TPI乳液,乳液稳定性较好。初步分析,共沉淀蛋白中的大豆蛋白组分能更好地覆盖油水界面,提高了乳液贮藏的物理稳定性,而鱼蛋白组分能够减缓油脂的氧化速率,提高了乳液贮藏的氧化稳定性。TSPC乳液具有优于TPI乳液的物理稳定性和优于SPI乳液的氧化稳定性,可用作良好的乳化剂稳定DHA藻油。该研究结果可为共沉淀蛋白功能乳液的开发提供参考。

乳清分离蛋白-葡萄糖的美拉德反应产物及其在藻油乳液凝胶中的应用

利用乳清分离蛋白和葡萄糖在湿法条件下发生美拉德反应,研究不同质量比对美拉德反应进程、反应产物抗氧化性的影响,并用美拉德反应产物制备负载藻油的乳液凝胶。结果表明,乳清分离蛋白-葡萄糖美拉德反应中间产物、褐变程度和接枝度在质量比2∶3(w/w)时达到最大值,分别为1.981%、0.715%和31.336%,同时,荧光光谱表明接枝后的糖链具有掩蔽效应,美拉德产物的亲水性增加。质量比1∶1时,反应产物DPPH自由基清除能力达到最大值,为81.88%,显著高于未发生美拉德反应组(P<0.05)。最终得到的乳液凝胶质构特性和冻融稳定性有所下降,但在光照和温度储藏期间仍具有良好的氧化稳定性。上述研究表明,乳清分离蛋白-葡萄糖的美拉德反应有效改善了乳清分离蛋白的特性,对负载藻油的乳液凝胶具有较好的抗氧化效果。

计算机模拟筛选食用藻蛋白源PAR2抑制肽

该研究主要是通过计算机模拟,从食品来源蛋白质中预测筛选具有蛋白酶激活受体2(Protease Activated Receptor 2,PAR2)抑制作用的生物活性肽,同时预测食用藻类蛋白质酶解后所得的肽段的生物活性、水溶性等理化指标。首先,利用NCBI数据库和蛋白质晶体数据库(Protein Data Bank,PDB)比对选择食用藻类蛋白质,其次通过BIOPEP-UWM数据库模拟酶解,Peptide Ranker进行活性分析,Innovagen和ToxinPred预测高活性肽,最后采用HPEPDOCK将获得的活性评分超过0.5、水溶性优且无毒的小分子活性肽与PAR2进行分子对接模拟,以探究两者之间的分子结合能力,进而分析判别不同小分子活性肽抑制PAR2活力的潜力和机制。结果表明,小分子寡肽PAGR(-165.80)、PAR(-163.93)、IDQW(-152.95)、DISAW(-154.48)与PAR2具有较高的结合分数,是PAR2潜在的活性抑制肽。该研究旨为藻类蛋白的开发利用以及PAR2抑制剂的挖掘研究提供参考。

不同生物活性的藻蛋白和多肽的作用机制及应用的研究进展

藻蛋白和多肽具有多种药理作用,在化妆品、保健品和医药领域应用广泛。了解藻蛋白和多肽的作用机制对其在各领域中的产品研发有着重要的意义。综述了近年来具有不同生物活性的藻蛋白和多肽的研究成果,以期为藻蛋白和多肽的进一步开发及应用提供科学参考。

油相结构化对大豆蛋白藻油纳米乳液氧化稳定性的影响

利用蜂蜡结构化藻油结合大豆分离蛋白-甜菊糖(soy protein isolate-stevioside,SPI-STE)复合体系的乳化特性,制备高稳态的藻油纳米乳液体系。藻油凝胶的微观结构观察、热性质测试以及流变学分析表明,当藻油中蜂蜡添加量达到4%(m/m)时,大量晶体组装成稳固的网络结构,从而构筑出稳定的油凝胶。进一步以SPI-STE为稳定剂制备藻油纳米乳液,研究了藻油结构化对纳米乳液形成及稳定性的影响。结果表明,油相中添加蜂蜡对纳米乳液的形成没有显著影响。随着藻油中蜂蜡质量分数的增大(0%~6%),乳液的物理稳定性逐渐提高;但在高蜂蜡添加量(8%)下,刚性较强的凝胶网络破坏了油滴界面层,乳液稳定性变差。热促氧化及光促氧化结果显示,蜂蜡油相结构化明显提高了纳米乳液的氧化稳定性,其中油相中含有6%蜂蜡的样品延缓氧化的效果最明显。本研究可为食品工业构建高稳态的藻油纳米乳液载体及产品提供一定技术支持。

盐度对三角褐指藻生长及有机质积累的影响

以三角褐指藻为材料,探究盐度对该藻生长、总脂等有机质含量的影响,探讨有利于油脂生产的盐度条件。结果显示,盐度变化对三角褐指藻生物量和有机质积累均有显著影响。在盐度70‰的海水中培养的细胞,其比生长速率比正常海水盐度(35‰)培养组降低了8.2%。正常海水盐度下,生物量及总脂含量最高,分别达1.92g/L和29.98%,且总脂单位体积产量极显著(p<0.01)地高于其他各组,藻油产量高达47.67mg.L-1.d-1。在盐度17‰时,多糖含量最高,达5.5%。在盐度70‰时,蛋白质含量最高,达17.82%。

海藻色素糖蛋白对肝癌细胞Caspase-3和Bax蛋白表达影响

目的研究麒麟菜海藻色素糖蛋白(SPG)对肝癌细胞Caspase-3和Bax蛋白表达的影响。方法将50只皮下接种H22肝癌细胞株的小鼠随机分为5组,每组10只。高、中、低剂量SPG组分别每天经口灌胃给予100、50、10 mg/kg的SPG,灌胃体积0.5 mL;肿瘤对照组灌胃给予等体积生理盐水;环磷酰胺组隔天腹腔注射环磷酰胺20 mg/kg,连续10 d。于末次给药后第2天将全部小鼠处死,取肝癌组织,用MTT法测定各组肝癌细胞增殖活性,免疫组织化学法检测Caspase-3和Bax蛋白表达水平。结果中、高剂量SPG组Caspase-3和Bax蛋白阳性表达率高于肿瘤对照组,肝癌细胞增殖活性明显低于肿瘤对照组,差异均有显著性(F=344.264～19 266.181,q=14.88～185.56,P<0.05)。结论 SPG可促进肝癌细胞Caspase-3和Bax蛋白表达,进而诱发肝癌细胞凋亡。

钝顶螺旋藻藻蛋白体外抗氧化能力研究

以钝顶螺旋藻为材料,采用反复冻融法提取藻蛋白粗提物,运用考马斯亮蓝法测定藻蛋白含量。通过钝顶螺旋藻藻蛋白粗提物对DPPH、-OH、·O2-三种自由基的清除能力来评价其体外抗氧化性能,用VC作为对照。试验结果表明:冻融次数6次、冷冻时间6 h、冷冻温度-18℃、融化时间6 h、融化温度37℃时,钝顶螺旋藻藻蛋白的提取率达9.1%;钝顶螺旋藻藻蛋白对DPPH、-OH、·O2-这三种自由基的清除率IC50值分别为1.242、1.196、2.939 g/L,而VC对这三种自由基的清除率的IC50值分别为0.469、0.497、0.474 g/L。虽然钝顶螺旋藻藻蛋白的抗氧化性弱于VC,但其IC50值均小于10 g/L,仍表现出较强的抗氧化性。因此,研究为钝顶螺旋藻藻蛋白作为优质饲料开发提供了参考依据,同时为抗生素饲料的减少使用创造了可能。

两亲可降解聚酯涂层的制备及性能研究

利用两亲聚合物引发己内酯开环聚合制备了两亲可降解聚合物。通过X射线光电子能谱、原子力显微镜、水接触角等测试分析了材料的表面元素及表面性质,同时进一步通过附着力测试、抗蛋白吸附测试等抗藻类黏附测试来评估聚合物涂层的综合性能。结果表明:该涂层与基体的附着力较好,并能在水下保持长期稳定性,且蛋白质在涂层表面的吸附量几乎为零,表现出良好的抗蛋白质性能,同时,该材料还具有优异的抗藻类黏附性能。这种新型的两亲聚合物对海洋防污涂料的发展具有重要的意义。

Microcystin Levels in Selected Cyanobacteria Exposed to Varying Salinity

Microcystins produced by cyanobacteria pose a great threat to human health by releasing toxins upon cell death. In the present study, we studied microcystin production in the cyanobacterial strains Anabaena cylindrica (B629 and 2949) and Fremyella diplosiphon (SF33) exposed to 1, 2 and 4 g/L sodium chloride (NaCl). Cultures grown for 7 days in BG11/HEPES medium were pelleted, re-grown in the corresponding NaCl levels, and enzyme linked immunosorbent assay (ELISA) performed. ELISA assays revealed enhanced microcystin production in A. cylindrica B629 exposed to 4 g/L NaCl and A. cylindrica 29414 exposed to 2 and 4 g/L NaCl, after growth in the corresponding NaCl levels for 14 days. We observed a significant decrease (p > 0.05) in microcystin levels in the control strains after exposure to NaCl for 5 days. After exposure to 1, 2, or 4 g/L NaCl for 10 days, no microcystin release was observed in A. cylindrica B629, A. cylindrica 29414 or F. diplosiphon SF33. Sodium dodecyl sulfate polyacrylamide gel electrophoresis identified the presence of an additional band at 120 - 130 kDa in A. cylindrica B629 exposed to 2 and 4 g/L NaCl, and at 14 kDa in cultures amended with 1 and 2 g/L NaCl as well as the untreated control, indicating that exposure to salinity induces alterations in protein expression.

Isolation and Expression Analysis of Growth-Related Genes at Different Growth Stages of Dinoflagellate Alexandrium pacificum

Based on the transcriptomic sequencing, three genes of Alexandrium pacificum encoding ubiquitin(UBI), telomerase(TEL) and glycine-rich protein(GRP) relating to cell division were isolated and characterized. The full-length cD NA of GRP was obtained through approach of rapid amplification of c DNA ends(RACE). Four conserved domains, including DNA-and RNAbinding sites or motifs, cold shock domain at the N-terminal, and zinc-finger structure of CCCH type at the C-terminal were idenrtified. Phylogenetic analysis revealed that the deduced amino acid sequence of GRP tends to cluster together with proteins harboring cold shock domain. The expressions of these three genes were analyzed with quantitative PCR(qPCR). It was found that the expressions of these three genes at the logarithmic growth phase and induced logarithmic growth phase were all higher than those at lagging growth phase(P < 0.05). The expression patterns of these three genes were coincident with the proliferative capacity of the algae, e.g., displaying increased expression level at log and induced growth phases. The functions of these genes and their possible roles during harmful algal blooms(HAB) were discussed.

Reporter Gene Assay for Detection of Shellfish Toxins

Objective To explore the potential reporter gene assay for the detection of sodium channel-specific toxins in shellfish as an alternative for screening harmful algal bloom (HAB) toxins, considering the fact that the existing methods including HPLC and bioassay are inappropriate for identifying HAB toxins which poses a serious problem on human health and shellfish industry. Methods A reporter plasmid pEGFP-c-fos containing c-fos promoter and EGFP was constructed and transfected into T24 cells using LipofectAMINE 2000. Positive transfcctants were screened by G418 to produce a pEGFP-c-fos-T24 cell line. After addition of increasing neurotoxic shellfish poison (NSP) or GTX2,3, primary components of paralytic shellfish poison (PSP), changes in expression of EGFP in the cell line were observed under a laser scanning confocal microscope and quantified with Image-pro Plus software. Results Dose-dependent changes in the intensity of green fluorescence were observed for NSP in a range from 0 to 10 ng/mL and for GTX2,3 from 0 to 16 ng/mL. Conclusion pEGFP-c-fos-T24 can be applied in detecting HAB toxins, and cell-based assay can be used as an alternative for screening sodium channel-specific HAB toxins.

两型饲料的能量和新型蛋白质替代原料

两型饲料是指资源节约型和环境友好型饲料。目前,市场上猪、肉鸡和蛋鸡的日粮以玉米豆粕型为主,需要新的解决方案来改善饲料生产可持续性和解决工农争粮问题。有许多原料可作为替代能量和蛋白质来源正受到人们的关注,其中包括高粱、大麦、昆虫源性原料、藻源性蛋白和单细胞蛋白等。文章主要论述了两型饲料中纤维的重要性以及几种能量和新型蛋白质替代猪只饲料原料的应用前景。

软骨藻酸对原代培养大鼠神经胶质细胞膜的影响

目的研究软骨藻酸（domoic acid，DA）对原代培养大鼠神经胶质细胞膜的损伤作用。方法6．4×10^-2、6．4×10^-3,6．4×10^-4μmol／L的DA作用于原代培养的大鼠神经胶质细胞24h后，分别测定细胞Na^＋-K^＋-ATPase和Ca^2＋-Mg^2＋-ATPase的活力、细胞膜流动性和通透性的变化。结果神经胶质细胞经DA处理后，Na^＋-K^＋-ATPase和Ca^2＋-Mg^2＋-ATPase的活力均明显受到抑制，细胞膜的流动性降低、通透性升高，低、中、高剂量DA染毒组荧光偏振度分别为0．0626±0．0051、0．0685±0．0097、0．0648±0．0086，微黏度分别为0．3154±0．0298、0．3510±0．0571、0．3286±0．0504，与对照组（荧光偏振度为0．0481±0．0069，微黏度为0．2338±0．0372）相比，差异均有统计学意义（P〈0．01）。结论DA能明显损害神经胶质细胞膜的功能，进而可能引发细胞的其他损伤。

多目标因素钝顶螺旋藻藻蛋白提取工艺分析

以钝顶螺旋藻藻粉为试验材料,采用反复冻融法提取藻蛋白,研究不同浸泡时间(2,6,10,22和48 h),不同料液比(1︰10,1︰20,1︰30,1︰40和1︰50(g/mL)),不同冻融时间(0,2,4,6,8和10 h),不同冻融次数(0,2,4,6,8和10次)对钝顶螺旋藻藻蛋白提取率的影响。基于单因素试验结果,采用L9(34)进行正交试验设计,结果表明4个因素影响效果为:冻融时间最大,其次是冻融次数、浸泡时间,最后是料液比,最优提取工艺条件为料液比1︰20(g/mL)、浸泡时间22 h、冻融时间6 h、冻融次数6次。试验结果为钝顶螺旋藻在食品领域的深加工与利用提供理论依据。

衣藻叶绿体表达重组蛋白及表达优化策略

近年来,转基因技术已日趋成熟,医学、工业上的应用也越来越广泛。以重组蛋白为基础的药物治疗是目前医药生产领域发展最快的一项技术。它们的高特异性和低副作用使得治疗效率十分突出。但是重组蛋白表达的复杂性也给生产带来了一定限制。为了促进重组蛋白的应用,人们对适宜其表达的系统和能促进其表达的策略进行了探索。研究发现,衣藻叶绿体作为重组蛋白的生物反应器,能实现重组蛋白快速、高效、低成本生产。同时,衣藻能在人工培养基和人为控制的条件下生长,降低了受污染的风险,与传统的生产系统比较具有不可比拟的优越性。因此,衣藻叶绿体作为医药重组蛋白生物反应器在未来的生物技术领域将发挥巨大作用。