可控酶法制备河蚬抗氧化肽工艺优化

为优化酶法制备河蚬抗氧化肽的最佳工艺条件,在单因素试验的基础上,利用Box-Behnken中心组合试验和响应面分析法,研究不同因素水平时酶解产物对羟自由基清除率的影响。获得河蚬抗氧化肽的最佳制备条件为:添加0.94%中性蛋白酶(以河蚬肉计),在料液比1∶2(m∶V),pH 6.00,温度54.70℃的条件下酶解3.91h,该条件下羟自由基清除率为81.63%。     

河蚬免疫活性糖蛋白分离及结构初步分析

采用DEAE-52纤维素柱层析,SephadexG-75葡聚糖凝胶层析和RP-HPLC柱层析手段分离纯化,从河蚬中分离纯化得到一种酸性糖蛋白CFP。经RP-HPLC和SDS-PAGE测定,CFP纯度为94.74%,其相对分子量为19030D。经苯酚-硫酸法测定,CFP的含糖量为5.18%,蛋白质含量为93.22%。碱性β-消除反应表明,河蚬糖蛋白中存在O-糖肽键。经红外光谱分析,CFP具有多糖的特征吸收,含有吡喃糖β-型糖苷键。     

河蚬中水溶性蛋白的提取及其抗氧化性质

研究超声波辅助法提取河蚬水溶性蛋白的工艺。以水溶蛋白的提取率为考察指标,以料液比、提取时间、提取温度和超声功率为考察因素,采用响应面法对河蚬水溶性蛋白提取工艺条件进行优化设计,并对其进行抗氧化研究。结果表明：最佳河蚬水溶性蛋白提取工艺条件为料液比1∶20、提取时间23 min、提取温度48 ℃、超声功率920 W,此条件下河蚬水溶性蛋白提取率达到最大值,为67.70%。其中,提取时间和超声功率对河蚬水溶蛋白提取率的影响显著。超声波的空化和振动作用可以促进细胞的破碎,使目标产物与溶剂充分混合,增大提取率,缩短提取时间,对河蚬中水溶性蛋白的提取具有很大意义。河蚬提取液具有较强的清除1,1-二苯基-2-三硝基苯肼自由基、超氧阴离子自由基的能力和较强的铁离子还原能力,而清除羟自由基的能力较弱。     

响应面法优化三相分离法提取河蚬汁多糖的工艺研究

目的 河蚬汁是河蚬煮蒸加工过程中随水蒸气流出的一种工业副产物,含有丰富的多糖、蛋白质等营养物质,往往被作为废水直接排掉,造成了资源浪费和环境污染。方法 本文首先对河蚬汁的基本成分进行分析,然后利用三相分离法（TPP）从河蚬汁中提取河蚬汁多糖,以硫酸铵质量分数、叔丁醇与河蚬汁体积比、提取温度和时间作为单因素变量,以多糖提取率和可溶性蛋白含量为指标,利用单因素试验结合响应面优化确定TPP提取河蚬汁多糖的最佳工艺条件。结果 研究表明,通过单因素分析和响应面优化得到的TPP提取河蚬汁多糖的最佳工艺条件为：硫酸铵质量分数26.0%（w/v）、叔丁醇与河蚬汁体积比1.4：1.0（v/v）、温度37.0 oC、时间30 min。在最佳提取条件下,河蚬汁多糖提取率的预测值为49.80%,实验值为48.05 ± 1.09 %,实验值和预测值相差1.75% ,表明响应面模型是正确、可行的。结论 TPP是一种绿色、高效分离多糖的方法,本研究对实现河蚬汁的综合利用,提高其工业附加产值而言具有重要的现实意义。     

Small hydropower dam alters the taxonomic composition of benthic macroinvertebrate assemblages in a neotropical river

Hydropower dams substantially modify lotic ecosystems. Most studies regarding their ecological impacts are based on large dams and provide little information about the far more abundant effects of small hydropower dams. Our aim was to characterize the ecological effects of a small hydropower dam and run‐of‐the‐river reservoir on the structure of benthic macroinvertebrate assemblages in the Pandeiros River located in the neotropical savanna of Brazil. We tested the hypothesis that benthic macroinvertebrate assemblages in sites directly affected by the dam and reservoir would show a different taxonomic structure compared with those in free‐flowing sites. We expected to find sensitive native species associated with the free‐flowing sites, whereas resistant and non‐native invasive taxa were expected in impounded sites. We also explored associations between the presence of native and non‐native invasive taxa to each habitat type. We found that the structure of benthic macroinvertebrate assemblages was significantly different between free‐flowing and impounded sites. Also, we found that the dam and reservoir facilitated colonization of non‐native invasive species (Corbicula fluminea and Melanoides tuberculata) because only in those sites they were found in high abundance, in contrast to the free‐flowing sites. Although the environmental conditions imposed by the impoundment altered the structure of benthic macroinvertebrate assemblages, the effects were limited to sites closest to the dam. Our results highlight the necessity of understanding physical habitat changes caused by the presence and management of run‐of‐the‐river dams and reservoirs.     

河蚬糖蛋白体外免疫功能研究

目的:研究河蚬糖蛋白对小鼠体外免疫功能的影响。方法:无菌分离小鼠脾淋巴细胞和腹腔巨噬细胞,与不同质量浓度(5、25、125、625μg/mL)的河蚬粗糖蛋白和高纯度糖蛋白CFP共同培养,采用MTT法测定其对淋巴细胞增殖和腹腔巨噬吞噬能力的影响。结果:在无有丝分裂原诱导下,125μg/mL的粗糖蛋白和4个浓度的CFP都有促进脾淋巴细胞的作用。在有丝分裂原刺激下,粗糖蛋白和CFP的刺激指数都比未加有丝分裂原时增大。125μg/mL粗糖蛋白和4个浓度的CFP都有提高巨噬细胞的吞噬能力,且2种河蚬糖蛋白都表现出一定的剂量效应关系。结论:河蚬粗糖蛋白和CFP均有免疫增强活性,其中CFP的活性较强。     

太湖河蚬软体部分6种矿物质元素的含量及相关性分析

以西太湖宜兴市水域产河蚬为材料,利用电感耦合等离子质谱仪测定其软组织中矿物质元素Na、K、Mg、Mn、Cu和Se的含量。结果表明:6种矿物质元素在河蚬体内的含量由高到低依次为Na、K、Mg、Mn、Cu、Se,其平均值分别可达1215.2、763.4、656.2、115.6、65.8、3.2mg/kg(以干质量计);太湖产河蚬的Cu、Mn、Se元素含量较高,Na-K、Na-M g、Na-S e、Mg-S e、Mg-K和K-Se等营养元素之间有协同积累的趋势。     

河蚬营养成分的提取及其生理功能研究进展

河蚬(Corbicula fluminea)是一种双壳类软体动物,富含蛋白质、多糖、不饱和脂肪酸、矿物质及维生素等营养物质,具有清热解毒、醒酒护肝、利尿明目等多种生理功能。近年来,研究发现河蚬提取物能够抑制肝癌细胞HepG-2的生长,清除O2^-·、·OH、DPPH·自由基,降低血清胆固醇,甘油三酯的含量,促进胆固醇代谢,减少动脉粥样硬化,调控乙醇代谢过程中的关键酶细胞色素P4502E1(CYP2E1)的表达,降低对人体有害自由基的生成,抑制脂质过氧化反应,减少脂质过氧化物的生成,可以有效缓解酒精对肝脏造成的损伤。本文主要阐述了河蚬的营养成分、提取方式、生理功能及其开发研究现状,为实现河蚬精深加工以及工业化生产提供理论依据。     

Lipid-lowering and LDL-oxidation inhibitory effects of aqueous extract of freshwater clam (Corbicula fluminea)--using tilapia as an animal model

A previous study has demonstrated that tilapia able to exhibit hyperlipidemia and hypercholesterolemia is a good model for the evaluation of beneficial effects of nutraceuticals. In this study, tilapia were used to evaluate the in vitro and in vivo effects of a hot water extract (FC-HW) of freshwater clam (Corbicula fluminea). FC-HW prolonged the lag phase of Cu(2+)-induced human and tilapia LDL oxidation. The prolongation of the lag phase was concentration-dependent in human (r(2)= 0.94) and tilapia LDL (r(2)= 0.98). The antioxidative potential of FC-HW was 0.33% (on a weight basis) of Trolox, a positive control. Male tilapia (n= 24) were randomly divided into 2 groups and separately fed for 60 d with an isocaloric also isoprotein diet containing 2% (w/w) FC-HW or a control diet. Body length and body mass were significantly higher in fish fed FC-HW than those of the control group (P < 0.05). Total triacylglycerol, cholesterol, and LDL-C in plasma of the FC-HW group were significantly lower (-89.9%, -61.8%, and -54.5%, respectively), while plasma total antioxidant capacity of the FC-HW group was higher and the lag phase in Cu(2+)-induced LDL oxidation was longer than those of the control group (P < 0.05). FC-HW demonstrated hypolipidemia and hypocholesterolemia effects and inhibited human LDL oxidation in vitro and tilapia LDL both in vitro and ex vivo, indicative that FC-HW can be a potential nutraceutical to reduce the risk factors of atherosclerosis.