RAW TROPICAL OYSTERS AS VEHICLES FOR MULTIDRUG-RESISTANT Vibrio parahaemolyticus

The following study aimed to determine the antimicrobial susceptibility profile ofVibrio parahaemolyticus strains from fresh and frozen oystersCrassostrea rhizophorae sold in Fortaleza-Brazil. An antibiogramwas performed on 87 isolates using nine antibiotics: gentamicin (Gen 10 µg),ampicillin (Amp 10 µg), penicillin G (Pen 10U), ciprofloxacin (Cip 5 µg),chloramphenicol (Chl 30 µg), nalidixic acid (Nal 30 µg), tetracycline (Tet 30 µg),vancomycin (Van 30 µg) and erythromycin (Ery 15 µg). All strains were resistant to atleast one antibiotic, and 85 (97.7%) were multi-resistant, with predominance of theVan+ Pen+Amp resistance profile (n = 46). Plasmid resistance to Pen, Amp and Ery wasdetected. Thus, the risk that raw oyster consumption poses to the health of consumersis highlighted, due to the fact that these bivalves may host antibacterial-resistantmicroorganisms.     

粗江蓠多糖对辐射损伤小鼠NK细胞的影响

目的：研究粗江蓠多糖（Gracilaria Gigas Harvey Polysaccharides,GHPS）对辐射损伤小鼠NK细胞的影响。方法：采用60Coγ射线5Gy全身照射小鼠制造辐射损伤模型,通过乳酸脱氢酶释放法检测不同剂量（10mg/kg,20mg/kg,40mg/kg）的GHPS对辐射损伤小鼠NK细胞杀伤靶细胞能力的影响。结果：辐射对照组小鼠接受60Coγ射线5Gy照射后,NK细胞的活性显著低于正常对照组（P〈0.01）。经腹腔注射（10、20、40）mg/kg GHPS,再接受γ射线5Gy照射后,小鼠NK细胞活性明显高于辐射对照组（P〈0.01）,并有剂量依赖性。结论：5Gyγ射线可以抑制小鼠NK细胞杀伤靶细胞的活性,而GHPS对辐射损伤小鼠的NK细胞有保护作用。     

Insulin-like system and growth regulation in the Pacific oyster Crassostrea gigas: hrIGF-1 effect on protein synthesis of mantle edge cells and expression of an homologous insulin receptor-related receptor

The involvement of molecules belonging to the insulin/IGF family in regulation of growth has been investigated in the Pacific oyster Crassostrea gigas. In vitro biological effects of human recombinant IGF-1 (hrIGF-1) on mantle edge cells, involved in oyster shell and soft body growth, were studied over an annual cycle. In mantle edge cells hrIGF-1 stimulates protein synthesis of 56+/-5.1% over basal for 10(-10) M in September with in addition a clear dose-effect corresponding to the highest shell growth period, and 57.5+/-3.45% over basal for 10(-11) M in March and 51+/-5.4% over basal for 10(-10) M in April corresponding to the period of mantle growth. These insulin-like effects were associated with the expression of a recently identified C. gigas insulin receptor-related receptor (CIR) in mantle edge cells as demonstrated by RT-PCR. Moreover, in situ hybridisation (ISH) confirmed this expression at the level of the inner and outer epithelia involved in mantle growth and shell formation.     

Tracing cadmium contamination kinetics and pathways in oysters (Crassostrea gigas) by multiple stable Cd isotope spike experiments

Laboratory experiments using stable Cd isotopes (¹¹⁰Cd and ¹¹²Cd) were conducted to separately and simultaneously characterize Cd accumulation in different tissues of Pacific oysters (Crassostrea gigas) via the (i) trophic and (ii) direct pathways. For this, we exposed juvenile oysters to ¹¹⁰Cd-spiked seawater (¹¹⁰Cd: 2 μg l⁻¹; constant level) and ¹¹²Cd-spiked food (Thalassiossera weissflogii, ¹¹²Cd: 2 μg l⁻¹ in 35×10³ cells/oyster/L) in four experimental treatment groups, each containing 6 oysters, for 21 days with constant trophic feeding. These Cd contamination levels were ∼10 times lower than those typically used in experimental accumulation studies. Three oysters per treatment group were dissected every 7 days with separate sampling of the gills, digestive gland and the rest of the body. Metallothioneins were analysed in the digestive gland and gills. Cadmium concentrations and isotope ratios were measured in water (daily) and tissues (weekly) by GF-AAS and ICP-MS. The observed time-dependant evolution in Cd concentrations and ¹¹⁰Cd/¹¹⁴Cd and ¹¹²Cd/¹¹⁴Cd isotope ratios clearly revealed the bio-accumulation short-term kinetics and pathways of Cd contamination in the different tissues. Under the experimental conditions, significantly changed isotope ratios in gills and the digestive gland of oysters suggested rapid and efficient contamination by ¹¹⁰Cd derived from direct exposure followed by internal Cd transfer between organs. Trophic contamination became measurable after 14 days of exposure corresponding to a trophic transfer rate of 1%. Constant metallothionein levels during the experiment suggested that the initially present metallothionein levels were sufficient to deal with the experimental Cd exposure.     

Implication of brevetoxin B1 and PbTx-3 in neurotoxic shellfish poisoning in New Zealand by isolation and quantitative determination with liquid chromatography-tandem mass spectrometry.

Brevetoxin B1 (BTX-B1) was isolated from Austrovenus stutchburyi following the 1992-1993 outbreak of neurotoxic shellfish poisoning (NSP) in New Zealand. We report here the first isolation of PbTx-3 from the same shellfish and the development of a procedure for quantitative determination of PbTx-3 and BTX-B1. PbTx-3 was isolated by chromatography on columns of SiO2, ODS, and LH-20, followed by reverse-phase HPLCs. In mass spectrometry (MS) with an electrospray ionization (ESI) interface operating in the positive or negative ion mode, the abundant protonated ion [M+H]+ of PbTx-3 (m/z 897) and the de-sodiated ion [M-Na]- of BTX-B1 (m/z 1016) were generated, respectively. These served as precursor ions for collision-induced dissociation, and the product ions of m/z 725 from PbTx-3 and m/z 80 from BTX-B1 were identified, allowing unambiguous confirmation of these toxins by selected reaction monitoring liquid chromatography-tandem mass spectrometry (SRM LC-MS/MS) analysis. The determination limits were 0.4 and 2 ng/g for BTX-B1 and PbTx-3 at a signal-to-noise ratio of five, respectively. This LC-MS/MS method was successfully applied to determine BTX-B1 and PbTx-3 in the NSP-associated toxic shellfish. BTX-B1 was found in both A. stutchburyi and Perna canaliculus, but not in Crassostrea gigas, while PbTx-3 was found in all three.     

牡蛎中糖蛋白成分的分离纯化与理化性质的初步分析

目的 从牡蛎蛋白质中分离糖蛋白并对其理化性质进行初步研究.方法 以青岛牡蛎为原料,通过低温水提取工艺得到牡蛎糖蛋白粗提物,用凝胶柱层析(Sephacryl s-100 HR)进行纯化,最后用高效液相色谱制备得到3个组分F22,F33,F42.结果 理化性质的研究表明组分F22等电点分别是5.5.其相对分子质量为34230Da,F22,F33,F42的蛋白含量分别为34.1%、19.7%及12.5%,其糖含量分另q为35.9%、28.8%及40%.结论 本研究将为牡蛎中活性物质的研究提供参考.     

朝鲜当归提取物对小鼠脑缺血-再灌注损伤神经的保护作用及其机制

目的探讨朝鲜当归提取物对小鼠脑缺血-再灌注(I/R)损伤影响及其机制。方法雄性C57BL/6小鼠随机分为6组,分别为假手术组、模型对照组和朝鲜当归(10,25,50,100 mg·kg^-1)组(n=9)。I/R小鼠采用大脑中动脉阻塞(MCAO)方法使小鼠短暂缺血90 min,再灌注24 h。应用2,3,5-氯化三苯基四氮唑染色法和伊文思兰染色评价大鼠脑梗死体积和血-脑屏障通透性变化;利用蛋白免疫印迹(Western blotting)方法检测血管生成诱导蛋白如血管生成素1(Ang-1)和血管内皮生长因子(VEGF)表达,紧密连接蛋白如ZO-1和Occludin表达;同时检测磷脂酰肌醇3-激酶(PI3K)/Akt磷酸化表达。结果朝鲜当归提取物可显著缩小I/R小鼠脑梗死体积(P<0.05),降低I/R小鼠血-脑屏障通透性(P<0.05),还可激活PI3K/Akt通路,增加Ang-1、VEGF、ZO-1和Occludin蛋白表达(P<0.05)。结论朝鲜当归可能通过降低血脑屏障通透性及促进血管生成在小鼠I/R损伤中发挥神经保护作用。     

牡蛎活性肽的制备及其理化性质的初步研究

目的从牡蛎蛋白质的酶解物中分离制备活性肽并对其理化性质进行初步研究。方法采用胰蛋白酶对牡蛎蛋白质进行酶解,使其释放出具备特殊活性的活性肽,将含有活性肽的粗提物分别用Sephadex G25凝胶柱层析,DEAE-Sepharose FF离子交换柱层析和C18反相柱进行分离和纯化。结果牡蛎活性肽粗提物经过分离纯化制备出3个组分F31,F32,F41。组分F32,F41的等电点分别是7.12和7.08;组分F31,F32,F41的相对分子质量分别为885,810及409;其蛋白含量分别为51.9%,80.2%及99.8%;其糖含量分别为19.2%,4.3%及0%。结论以胰蛋白酶作用的最佳条件采用一步酶解的工艺,牡蛎蛋白质可以得到良好的酶解,同时得到的牡蛎活性肽粗提物活性较高。