香螺生物体内的微量元素分析及食用安全性

利用电感藕合等离子发射光谱仪(ICP-AES)技术对香螺生物体内的16 种微量元素进行分析,同时进行食用安全性研究,并比较未经清水浸泡和经清水浸泡2d 后,其生物体内微量元素的变化情况。香螺经清水浸泡后,一些微量元素会随体内一些污物排掉而减少,而一些重金属污染元素难以从生物体内排除掉。香螺生物体内含有丰富的矿物元素(如Ca、K、Na 和Mg),其值每千克超过几百毫克,并含有丰富的具有生理功效的营养微量元素(如Fe、Zn、Mn、Ge、Cr 和Ni 等),其中Fe 和Zn 含量分别可达到每公斤30mg 和20mg 以上,但Mg 和Cu 元素明显较日常膳食推荐高,香螺生物体内存在重金属的潜在污染源主要为As 和Hg 元素。     

菊苣醇提物对对乙酰氨基酚诱导小鼠肝损伤的保护作用

目的研究菊苣醇提物对对乙酰氨基酚(acetaminophen,APAP)诱导的小鼠肝损伤的保护作用。方法将56只昆明小鼠随机分为7组:分别是阴性对照组,APAP模型组,水飞蓟宾阳性对照组,菊苣醇提物单独给药组(200 mg/kg体重),菊苣醇提物低、中和高剂量(50、100和200 mg/kg体重)与APAP联用组。各剂量组小鼠灌胃给予对应药物连续7 d后,一次性腹腔注射APAP(300 mg/kg体重)构建肝损伤模型,24 h后采集肝组织样品和血清。分别测定肝组织和血清的多种氧化指标以及细胞色素P450 2E1酶(CYP2E1)的蛋白表达水平。结果菊苣醇提物能够显著降低血清中谷丙转氨酶(alanine aminotransferase,ALT)和谷草转氨酶(aspartate aminotransferase,AST)水平。降低肝组织中过氧化氢(hydrogen peroxide,H2O2)和谷胱甘肽(glutathione,GSH)的含量以及提高抗氧化酶系中过氧化氢酶(catalase,CAT)和总超氧化物歧化酶(total superoxide dismutase,T-SOD)活性;同时,体外抗氧化实验亦表明其具有良好的清除自由基的能力。另外,菊苣醇提物还能够显著抑制CYP2E1的蛋白表达。结论菊苣醇提物有助于维持小鼠体内酶防御系统功能,提高机体清除自由基的能力,并通过减少CYP2E1的蛋白表达对APAP所致小鼠肝损伤具有明显保护作用。     

仙草提取物对CCl_4致小鼠肝损伤的保护作用

将70只雄性昆明小鼠随机分成7组:正常对照组、模型对照组、阳性对照组、醇提组、水提低、中、高剂量组.醇提组按500 mg/kg灌胃仙草醇提物,低、中、高剂量组分别按200、500、1 000mg/kg灌胃仙草水提物,阳性对照组按200 mg/kg灌胃联苯双酯,正常对照组和模型对照组以等体积蒸馏水灌胃,连续30 d.以CCl_4制成小鼠肝脏损伤模型,检测并比较各组小鼠血清中丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)活性和血清白蛋白(Alb)、甘油三酯(TG)含量,肝组织匀浆中丙二醛(MDA)含量和超氧化物歧化酶(SOD)、谷胱甘肽(GSH)、谷胱甘肽过氧化物酶(GSH-PX)活性.仙草水提物低、中、高剂量组与模型对照组相比均能显著降低ALT(P<0.05)、AST、TG值(P<0.01),显著增加Alb含量(P<0.05),极显著降低小鼠肝组织匀浆MDA值(P<0.01),极显著升高GSH、GSH-PX值(P<0.01),对SOD酶活性(P>0.05)无显著影响;同时,仙草水提物低、中、高剂量组与联苯双酯阳性对照组相比各指标无显著差异(P>0.05),而仙草醇提物与模型对照组相比上述各生化指标无显著差异(P>0.05).仙草水提物对CCl_4所致的小鼠肝损伤具有一定保护作用.     

In vitro scavenging capacity of annatto seed extracts against reactive oxygen and nitrogen species

Bixa orellana L. (annatto), from Bixaceae family, is a native plant of tropical America, which accumulates several carotenoids (including bixin and norbixin), terpenoids, tocotrienols and flavonoids with potential antioxidant activity. In the present study, the in vitro scavenging capacity of annatto seed extracts against reactive oxygen species (ROS) and reactive nitrogen species (RNS) was evaluated and compared to the bixin standard. Annatto extracts were obtained using solvents with different polarities and their phenolic compounds and bixin levels were determined by high performance liquid chromatography coupled to diode array detector. All annatto extracts were able to scavenge all the reactive species tested at the low μg/mL range, with the exception of superoxide radical. The ethanol:ethyl acetate and ethyl acetate extracts of annatto seeds, which presented the highest levels of hypolaetin and bixin, respectively, were the extracts with the highest antioxidant capacity, although bixin standard presented the lowest IC₅₀ values.     

The cyanobacterium Oscillatoria erythraea--a potential source of toxin in the ciguatera food-chain.

A compound lethal to mice (i.p.) was extracted from samples of Oscillatoria erythraea, four species of mollusc and one species of molluscivorous teleost collected from the south-east coast of Queensland, Australia, during and shortly after O. erythraea blooms. The compound was chemically indistinguishable from ciguatoxin (CTX) on the basis of solvent extraction and partitioning and silicic acid chromatography. Residues derived from toxic samples elicited signs of intoxication, death and histopathological changes in mice, consistent with extracts of ciguatoxic material. Stick enzyme immunoassay tests and thin layer chromatography assessment of extracts indicated the presence of ciguatoxin-like polycyclic ether(s). O. erythraea is implicated as a potential elaborator of a CTX-like compound in the tropical marine biota.     

Production and partial characterization of monoclonal antibodies specific to cooked poultry meat

Monoclonal antibodies (MAbs) specific to cooked poultry muscle proteins have been developed for the detection of poultry adulterants in cooked mammalian meat. Saline (0.85% NaCl) extract of heat-treated (100 °C, 15min) chicken muscle proteins was used to immunize mice for MAb development. The specificity of MAbs was tested against chicken antigen and protein extracts from seven other meat species (pork, beef, lamb, deer, horse, turkey and duck) by indirect enzyme-linked immunosorbent immunoassay (ELISA). The immunogenic components in the poultry protein extracts were determined by SDS-PAGE followed by immunoblotting. A total of six hybridoma cell lines that secrete IgG class MAbs have been developed: MAbs 3E12 and 1A5 were able to distinguish between cooked poultry and mammalian meats, MAbs 9C6 and 6F7 reacted strongly with cooked chicken only, and MAbs, 5D2 and 6G8, reacted with both cooked turkey and chicken but not other species. All six MAbs demonstrated a proportional increased ELISA response to respective adulterated poultry samples in pork over a 0-100% range of aduleration.     

Effect of aqueous extracts of some plants of Lamiaceae family on the growth of Yarrowia lipolytica

Aqueous extracts of some plants belonging to the Lamiaceae family (Sideritis montana, Origanum dictamnus, Mentha piperita, Rosmarinus officinallis and Origanum marjorana) caused an important increase of the lag time of Yarrowia lipolytica. Especially, Origanum dictamnus and Rosmarinus officinallis extracts enhanced the lag time considerably and influenced negatively the specific growth rate of this yeast. In culture media having low C/N ratio, all plant extracts caused an increase of the biomass produced in relation to glucose and nitrogen consumed, while, in high C/N ratio media the effect of the extracts on biomass production was negative. In the presence of aqueous plant extracts, in low C/N ratio culture media, the ratio sigma unsaturated/sigma saturated fatty acids in the cellular lipids increased, whereas in high C/N ratio media it decreased.     

Comparative characterization of monophenolase and diphenolase activities from a wild edible mushroom (Macrolepiota mastoidea)

In this study, Macrolepiota mastoidea, a wild edible mushroom, was evaluated for its polyphenol oxidase potential. Native electrophoresis, stained by l-dihydroxyphenylalanine, of the crude extracts from this species showed two bands having R_f values of 0.38 (minor) and 0.50 (major), supporting a polyphenol oxidase potential. The crude extracts showed monophenolase activity against 3-(4-hydroxyphenyl)-propionic acid and diphenolase activity against 4-methylcatechol as substrates. Monophenolase and diphenolase activities of enzyme extract prepared from M. mastoidea showed pH optimum values at pH 6.0 and pH 4.0, respectively. The extracts retained about 100% and 60% of their original monophenolase and diphenolase activities at their optimum pH values, respectively. It was estimated from thermodynamic data that M. mastoidea had a thermostable monophenolase activity. Thiourea and ascorbic acid were highly potential inhibitors for monophenolase, and ascorbic acid and sodium metabisulphite for diphenolase activity. It is clear from the present results that the enzyme extracts prepared from M. mastoidea possess polyphenol oxidase activities with interesting properties.     

Identification of the species of origin of fresh,cooked and canned meat and meat products using antisera to thermostable muscle antigens by ouchterlony's double diffusion test

Antisera to thermostable muscle antigens (TMA) from 14 species of bovidae were raised in goats and/or sheep. To achieve species specificity the antisera were absorbed with serum from the other species. While the absorbed antisera to TMA of buffalo, impala, eland, waterbuck, wildebeest and oryx were rendered specific, the antiserum to cattle TMA cross-reacted with buffalo fresh meat antigens (FMA) and cooked meat antigens (CMA) but not with buffalo thermostable muscle antigens. Fresh and cooked muscle antigens from these two species could be differentiated by the antiserum to buffalo TMA. A similar approach was used to differentiate the FMA, CMA, and TMA of kongoni, topi and wildebeest. Antiserum to cattle TMA proved useful in detecting the presence of beef meat in meat products that had undergone commercial sterilisation.     

海黍子石油醚相提取物的抑菌和免疫活性的研究

为了研究海黍子不同提取物的抗菌和免疫活性,将海黍子乙醇提取物依次用石油醚、乙酸乙酯、正丁醇进行萃取。取石油醚相进行硅胶柱层析,分离得P1～P77种物质,并对其进行抑菌(金黄色葡萄球菌、枯草杆菌、大肠杆菌、面包酵母菌、假丝酵母菌)和免疫活性(小鼠脾淋巴细胞、腹腔巨噬细胞增殖实验和NO释放实验)研究。结果表明,这7种提取物对面包酵母菌和假丝酵母菌没有抑制作用,而对细菌(金黄色葡萄球菌,枯草杆菌和大肠杆菌)的抑制效果比较理想。免疫实验表明,石油醚相的7个样品都具有一定的免疫活性,不但可以促进小鼠巨噬细胞RAW264.7增殖和体外刺激淋巴细胞增殖,还可以促进小鼠腹腔巨噬细胞产生NO。因此海黍子具有一定的抑菌和免疫活性,值得深入研究。     

草果甲醇溶出物抑制α-葡萄糖苷酶活性及调节血糖作用

目的:研究草果甲醇溶出物对α-葡萄糖苷酶的抑制作用及对小鼠高血糖的调节作用.方法:采用4-硝基酚-α-D-吡喃葡萄糖苷法(PNPG),以阿卡波糖为阳性对照,进行α-葡萄糖苷酶体外抑制试验,评估草果甲醇溶出物的α-葡萄糖苷酶抑制率.用高脂饲料喂养小鼠构建异常血糖小鼠模型,在高脂饲料基础上,分别添加100、200 mg/k...     

美味猕猴桃根各部提取物降酶保肝作用的研究

目的:观察美味猕猴桃根不同极性溶剂的提取物对四氯化碳(CCl4)肝损伤小鼠血浆转氨酶活性的影响。方法:用CCl4建立小鼠急性肝损伤模型,以不同的提取物和阳性对照药甘草酸二铵灌胃治疗,测定小鼠血浆中丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)活性。结果:各部位的提取物对小鼠四氯化碳(CCl4)肝损伤均有不同程度的保护作用,作用比较明显的是乙醇粗提物经乙酸乙酯萃取后,萃余物在大孔树脂柱上用60%～90%乙醇洗脱得到的提取物(A部位)(P<0.01)。结论:部位A对肝脏损伤有保护作用。     

亨氏马尾藻醇提取物体内降血脂及抗氧化作用

为了探究亨氏马尾藻醇提取物的降血脂和抗氧化作用,本文以溶剂法得到亨氏马尾藻醇提取物高、低两个剂量,灌胃急性小鼠高脂模型,观察马尾藻醇提取物对小鼠血脂指标的影响,并检测其在体内抗氧化活性。结果表明:亨氏马尾藻醇提取物低剂量组显著降低高脂血症小鼠血清中总胆固醇(TC)和低密度脂蛋白(LDL)含量以及其肝脏中甘油三酯(TG)和低密度脂蛋白(LDL)含量(p<0.05),脂蛋白脂肪酶(LPL)活力显著增强(p<0.05);高剂量组使血清中高密度脂蛋白(HDL)含量显著上升和低密度脂蛋白(LDL)含量显著下降以及其肝脏中甘油三酯(TG)显著降低(p<0.05);且两种剂量均可显著改善小鼠动脉粥样硬化指数AI1和AI2(p<0.05);同时,灌胃亨氏马尾藻醇提取物后,低剂量组使小鼠肝脏总抗氧化能力(T-AOC)、过氧化氢酶(CAT)活力显著上升(p<0.05),而丙二醛(MDA)水平显著降低(p<0.05),说明亨氏马尾藻醇提取物在降血脂和抗氧化作用方面具有潜在的应用。     

烟草牻牛儿基牻牛儿基焦磷酸合成酶基因家族的全基因组鉴定

为了揭示烟草牻牛儿基牻牛儿基焦磷酸合成酶(Geranylgeranyl pyrophosphate synthase,GGPPS)基因家族的特征和功能,利用生物信息学方法对烟草GGPPS家族进行了全基因组查找、鉴定及相关分析。在普通烟草中共鉴定出9个成员(大亚基7个、小亚基2个),林烟草、绒毛状烟草中分别鉴定出5个成员(大亚基4个、小亚基1个)。GGPPS的开放阅读框长度为999~1 119 bp,编码332~372个氨基酸,蛋白质分子量为36.2~40.7 kD,等电点为5.41~8.32。大亚基和小亚基基因分别含有1个和2个外显子;大亚基与小亚基均具有DD(XX)_1-2D和CXXXC保守性基序,但存在一定的差异。在进化过程中,烟草GGPPS家族可能发生了串联重复复制和片断复制;普通烟草GGPPS家族可能发生了基因丢失,NtabGGPPS1-1和NtabGGPPS1-2较其他成员进化速率快,同时可能受到了净化选择。      

A thermostable histamine oxidase from Arthrobacter crystallopoietes KAIT-B-007

A thermostable histamine oxidase (EC 1.4.3.-) was found in cells of Arthrobacter crystallopoietes KAIT-B-007 isolated from soil. The enzyme was purified about 715-fold over the cell free extracts with a yield of 55% by ammonium sulfate fractionation and various column chromatographies. The purified enzyme was homogeneous on polyacrylamide gel-electrophoresis (native-PAGE). When the enzyme was kept at 65 degrees C and 70 degrees C for 10 min, the activity was fully stable at 65 degrees C and decreased to 9% of the initial level at 70 degrees C. The enzyme was very thermostable. The optimum pH for histamine oxidase activity was found to be at 9.0, and the enzyme was stable over the pH range of 6 to 9. The purified enzyme showed a single protein band on SDS-PAGE and its molecular mass was estimated to be about 81 kDa. The enzyme showed potent activity toward histamine, whereas it was inactive toward putrescine, cadaverine, spermine, and spermidine. Histamine oxidase was inhibited by N,N-diethyldithiocarbamate (DDTC). The inactive enzyme was restored with Cu2+ to 65% of the initial activity, but Cu+ did not enhance the enzyme activity. It is suggested that Cu2+ is essential for expression of histamine oxidase activity. The enzyme was a copper-containing protein having one atom of copper per mol of the enzyme protein as a result of atomic absorption analysis. The N-terminal amino acid sequence of the purified enzyme was different from that of histamine oxidase from Arthrobacter globiformis IFO12137.     

Antioxidative Activities and Angiotensin I-Converting Enzyme Inhibition of Extracts Prepared from Chum Salmon (Oncorhynchus Keta) Cartilage and Skin

The extracts from cartilage and skin of chum salmon were prepared using a pressure cooker. As a result, protein and collagen contents in extracts from cartilage and skin was higher than those only in cartilage. The inhibition activity of linoleic acid oxidation was high in extract from cartilage. The scavenging activity of cartilage extract was higher than those of cartilage and skin against all reactive oxygen species, such as superoxide anion, hydroxyl, and DPPH radicals. On the other hand, angiotensin I-converting enzyme inhibitory activity of cartilage extract was about seven times as high as that of cartilage and skin extract. The present studies indicate that the extracts, particularly from cartilage, have angiotensin I-converting enzyme inhibitory activity that functions to depress hypertension, and antioxidant activity, which acts to prevent of life-style related diseases such as cancer, cardiovascular diseases, and diabetes. The data should be useful for developing a novel type of functional seasoning.     

三种海藻内生真菌的分离及其抑菌活性研究

从烟台浅海处采集到的鼠尾藻、裙带菜、海带三种海藻表面消毒后用PDA培养基将内生真菌进行分离纯化,将纯化的内生真菌进行液体培养7d后离心,菌丝体烘干研磨后用无水乙醇提取,分别测定发酵液和菌丝体乙醇提取物对七种植物病原真菌的抑菌活性。结果表明:三种发酵液都至少对三种病原菌有大于50%的抑菌活性,裙带菜发酵液对六种病原菌都有大于50%的抑菌率,最高为78.8%,说明它们能产生广谱高效的胞外代谢产物;而菌丝体提取物的抑菌活性并不明显,说明三种海藻内生真菌产生的胞内代谢产物无明显的抑菌活性。     

Fractionation of Extracts and Crystalline and Non-Crystalline Proteins from White Kidney Beans (Phaseolus vulgaris) by Ion-Exchange High-Performance Liquid Chromatography

Sodium hydroxide solution (0.02%) and citric acid solutions (0.08N, pH 5.5, CA1; 0.60N, pH 3.5, CA2) were used to extract proteins from white kidney beans (Phaseolus vulgaris). The extracts were subjected to ion-exchange high performance liquid chromatography (IE-HPLC) using a phosphate elution buffer (20 mM, pH 7.0). The charge properties of the protein fractions present in the NaOH extract and the CA1 and CA2 extracts were similar although the relative proportion of total peak area represented by each fraction was different in the different extracts. IE-HPLC of the isoelectric precipitate (amorphous microstructure) isolated from the CA1 (bipyramidal crystalline microstructure) and the CA2 (spheroidal microstructure) extracts indicated striking differences in the charge properties of the proteins which constituted the isolates. IE-HPLC also demonstrated that the precipitation processes did not affect the charge properties of the proteins which remained after the proteins were recovered from the different extracts.     

Species identification of autoclaved meat samples using antisera to thermostable muscle antigens in an enzyme immunoassay

An enzyme immunoassay (EIA) suitable for use in identification of cooked and autoclaved meat samples using antisera to thermostable muscle antigens (TMA) is described. Goat antisera to TMA of various species were tested against homologous and heterologous partially purified thermostable muscle antigens (PTMA) in an indirect EIA. Goat anti-eland and anti-cattle TMA sera were the poorest in differentiating other species PTMAs. Identification of various species PTMAs could be achieved using a battery of goat anti-TMA sera, where homologous goat anti-TMA serum fails to differentiate some of the PTMAs tested.     

Tropomyosins in gastropods and bivalves: Identification as major allergens and amino acid sequence features

Tropomyosin appears to be a major cross-reactive allergen of crustaceans and molluscs. In this study, four species of gastropods (disc abalone, turban shell, whelk and Middendorf’s buccinum) and seven species of bivalves (bloody cockle, Japanese oyster, Japanese cockle, surf clam, horse clam, razor clam and short-neck clam) were confirmed to be allergenic by ELISA and their major allergen identified as tropomyosin by immunoblotting. Inhibition immunoblotting data showed the cross-reactivity of gastropod and bivalve tropomyosins with one another and also with cephalopod and crustacean tropomyosins. Then, amino acid sequences of tropomyosins from 10 species except for Middendorf’s buccinum were elucidated by cDNA cloning. The known amino acid sequence data including our results reveal that molluscan tropomyosins share low sequence identities (about 60%) with crustacean tropomyosins and that they are highly homologous with one another within the same group (same family or same order) but not among the groups.