不同处理方法对葡萄牙牡蛎体内菌群净化效果的比较

牡蛎肉味鲜美,营养丰富,经济价值较高,素有海洋"牛奶"之美称。然而,由于养殖环境的污染,国内多数养殖牡蛎体内的大肠杆菌含量超标,危害公民健康。因此,研发养殖牡蛎净化技术日显重要。为此,本文以我国南方重要的养殖牡蛎(葡萄牙牡蛎,也称福建牡蛎)为对象,设计了三种净化方法 (大蒜素灭菌法、紫外灭菌法、混合灭菌法(大蒜素+紫外线)先灭菌处理海水6h,然后将牡蛎养殖灭菌后的海水中,并在0 h、12 h和24 h时分别对其软体组织进行取样,检测菌落总数和大肠杆菌含量,以探求最佳净化牡蛎方法。结果显示,三种方法都能够对牡蛎体内的菌落总量和大肠杆菌含量起到显著的净化作用。比较而言,大蒜素净化效果最佳,经12 h和24 h的净化后,牡蛎体内的大肠杆菌含量(MPN/100 g)由最初的2 307降至为240和189,显著低于紫外灭菌法的744和322以及混合灭菌法的384和359。经大蒜素净化24 h后,牡蛎体内的大肠杆菌含量为189 MPN/100 g,低于欧盟和我国双壳贝类养殖水域划分依据中规定的大肠杆菌含量≤230MPN/100 g时可以直接上市并供生食的标准。     

四倍体与二倍体太平洋牡蛎离体精子的存活能力比较

在不同海水温度和不同精子密度条件下对四倍体(4n)与二倍体(2n)太平洋牡蛎(Crassostrea gigasThunberg)离体精子的存活能力进行了比较.结果表明,四倍体与二倍体太平洋牡蛎精子的存活时间均随水温的升高和密度的降低而缩短,四倍体牡蛎精子的存活能力低于二倍体.四倍体牡蛎精子在海水温度10℃可存活8 h,在28℃仅存活2 h;二倍体牡蛎精子在10℃可存活12 h,在28℃仅存活4 h.四倍体牡蛎精子在较高密度(6.4×10<'7>个/Ml)下可存活8 h,较低密度(2.0×106个/Ml)下低于1 h;在与四倍体牡蛎精子相同的高、低密度下,二倍体存活时间分别超过10 h和1 h.     

温度、流速对中国蛤蜊吐沙净化的影响及效果评价方法研究

本研究在实验室条件下,以定量化口感测试和解剖法为评价方法,探讨不同温度和流速对中国蛤蜊吐沙净化的影响,并比较分析了两种评价方法可行性。实验设定14℃、18℃、22℃和26℃ 4个温度梯度,20 L/h、40 L/h、80 L/h、160 L/h和320 L/h 5个流速梯度。结果发现不同温度和流速对吐沙净化的影响不同,14℃和18℃时,流速对吐沙净化无显著性影响(P＞0.05),22℃和26℃时,流速对吐沙净化有显著性影响(P<0.05);14℃时,各流速的净化效果均不理想;18℃、22℃和26℃时,流速 40L/h下经4h~8h可达到较好净化效果。对两种评价方法进行比较表明,定量化口感测试评价方法能够较为准确的反映贝类泥沙净化效果,可以做为贝类泥沙净化效果的评价方法;通过解剖法获得贝类体内残余泥沙进行粒径分析,易受到非泥沙颗粒物的干扰,不能准确地反映贝类体内泥沙粒径与含量,在未对该方法进行进一步优化的条件下,不适宜做为吐沙净化的评价方法。     

雪菜鲐鱼方便食品的研制

研究开发了一种具有地方特色的方便食品——雪菜鲐鱼。对鲐鱼片采用去皮 ,复合盐液漂洗、压榨、雪菜汁浸渍等工序连续脱脂。研究的主要工艺参数确定如下 :复合漂洗液中Na HCO3 的最佳质量浓度为 2 0 kg/m3 ;用波美度为 6 .0的雪菜汁浸渍的时间是 1 h;调味鱼片在 40℃下干燥的时间为 5 .5 h;雪菜淡化时 ,雪菜用量 (kg)∶水体积 (L) =1∶ 4,淡化时间为 1 h;雪菜干燥的温度为 5 0℃ ,时间为 4h     

繁茂膜海绵清除大肠杆菌的过程

通过分析海绵清除大肠杆菌的过程,研究海绵净化细菌的机理。作者利用荧光显微镜和激光共聚焦显微镜观测等手段,监测和分析了绿色荧光大肠杆菌(Escherichia coli)在繁茂膜海绵(Hymeniacidon perlevis)体内、体外水环境中数量变化过程。在1 L含有3×107个/m L绿色荧光大肠杆菌的海水中放入鲜重(1.02±0.11)g的繁茂膜海绵24块,处理7 h,海水中的荧光大肠杆菌数量逐渐降低;而海绵体内荧光大肠杆菌数量在2 h时内逐渐增多,之后的2 h趋于稳定,4 h以后开始逐渐减少。水体中大肠杆菌不仅进入海绵体内,而且进入海绵细胞内。含有荧光大肠杆菌的海绵块转入无菌海水中后,海绵体内及细胞中大肠杆菌逐渐消失,而且大肠杆菌没有被释放到环境海水中。分析表明,繁茂膜海绵能够以摄食的方式净化水环境中的大肠杆菌。     

北部湾养殖牡蛎体内异养细菌数量及其耐药性研究

为了探究北部湾养殖区域香港牡蛎(Crassostrea hongkongensis)体内的异养细菌和弧菌数量及其耐药概况变化, 对不同养殖场牡蛎体内的异养细菌进行分离培养, 并统计其数量, 通过药敏纸片扩散等方法研究了细菌的耐药状况。结果显示: 牡蛎在高死亡率养殖环境中体内的异养细菌[(8.6±0.4)×10⁶CFU·g^-1]和弧菌[(9.5±0.4)×10⁵CFU·g^-1]数量较高, 在中死亡率环境中体内的异养细菌[(6.9±0.2)×10⁶CFU·g^-1]和弧菌[(4.5±0.6)×10⁵CFU·g^-1]数量次之, 在低死亡率养殖环境中体内的异养细菌[(3.3±0.1)×10⁶CFU·g^-1]和弧菌[(2.5±0.6)×10⁵CFU·g^-1]数量最低。耐药细菌主要为革兰氏阴性菌, 对β-内酰胺类(青霉素)、糖肽类(万古霉素)的耐药率较高, 对四环素类(四环素、多西环素)的耐药率次之, 对氨基糖苷类(链霉素、庆大霉素、妥布霉素、新霉素)、大环内酯类(红霉素)、喹诺酮类(诺氟沙星、环丙沙星、氧氟沙星、恩诺沙星)的耐药率较低。在高死亡率环境中牡蛎体内的多重耐药菌占79.7%, 其耐药谱型(48种)较广; 在中度死亡率环境中牡蛎体内的多重耐药菌占66.2%, 其耐药谱型为30种; 在低死亡率环境中牡蛎体内的多重耐药菌占58.4%, 其耐药谱型为17种。本文探究了牡蛎死亡率与其体内异养细菌数量和细菌耐药性的关系, 结果显示牡蛎在高死亡率环境中体内的耐药细菌数量多、耐药谱型较广, 低死亡率环境中牡蛎体内的耐药细菌数量较少, 异养细菌数量与牡蛎死亡率呈正相关关系, 两者相关系数为0.996。     

硝酸钠浓度对2株三角褐指藻生长及脂肪酸组成的影响

在温度为 (2 2± 1 )℃ ,盐度为 2 8的条件下 ,用含不同浓度硝酸钠 (75 ,3 75 ,75 0 ,11 2 5 ,1 5 0 0 ,1 875 mg/L)的培养基对青岛海洋大学微藻种质库保存的 2株三角褐指藻(Phaeodactylum tricornutum MACC/B1 1 8,MACC/B2 2 1 )进行培养。在指数生长期末期进行收获。测定了 2株硅藻的生长及脂肪酸组成。单因子方差分析结果表明 :硝酸钠浓度对 2株三角褐指藻相对生长率和影响差异不显著 ;对脂肪酸组成的影响因种而异 ,2株硅藻的主要脂肪酸为 1 4∶ 0 ,1 6∶ 0 ,1 6∶ 1 n- 7和 2 0∶ 5 n- 3 (EPA)     

温度和盐度对三倍体葡萄牙牡蛎(Crassostrea angulata)稚贝生长和存活的影响

为确定三倍体葡萄牙牡蛎(Crassostrea angulata)稚贝最适环境条件,研究了温度、盐度对其生长和存活的影响。结果表明:三倍体葡萄牙牡蛎稚贝适宜生存温度为11.05～33.81℃,最适宜生存温度为22.00～28.00℃;适宜生长温度为12.00～33.35℃,最适宜生长温度为26.00～28.00℃;温度胁迫条件下,该贝在48 h和96 h的半致死温度在低温端分别为(4.71±0.04)℃和(7.83±0.45)℃;高温端分别为(37.08±0.02)℃和(36.31±0.11)℃;存活率在高温端下降更迅速,表明稚贝对高温更敏感。在盐度耐受性方面:三倍体葡萄牙牡蛎稚贝适宜生存盐度为15.06～44.13,最适宜生存盐度为23.4～33.8;适宜生长盐度为11.76～45.39,最适生长盐度为23.40～26.00;该贝在48h和96h半致死盐度,低盐端分别为(4.68±0.97)和(9.35±0.35),高盐分别为(55.96±0.76)和(53.46±0.67)。综上,当水温为26.00～28.00℃,盐度为23.40～26.00时,更有利于三倍体葡萄牙牡蛎稚贝的存活和...     

不同温度下氟苯尼考在大菱鲆体内的药代动力学研究

研究了14和17℃2种不同养殖温度下,氟苯尼考在健康大菱鲆(Scophthalmus maximus)体内的药代动力学特征。以15mg/kg BW的剂量经静注和口灌2种方式给药后,于0.25、0.5、1、2、4、6、8、12、16、24、48和96h采集血液样品,采用Agilent1200型高效液相色谱仪测定样品中药物的含量,药时数据采用DAS2.0自动药动学软件进行分析。研究显示,14和17℃下,静注给药后的消除相半衰期(t1/2β)分别为18.20和12.46h,表观分布容积(Vd)分别为0.03和0.11L/kg,清除率(CL)均为0.02L/(h·kg)。口灌给药后血药浓度均在12h达到峰值,分布相半衰期(t1/2α)分别为2.84和4.08h,消除相半衰期分别为14.48和12.45h,生物利用度(F)分别为17.02%和18.24%。研究结果表明,温度升高会加快大菱鲆对氟苯尼考的吸收、体内分布和消除,提高口灌方式氟苯尼考利用效率。结合氟苯尼考药效学研究结果,提出给药方案:14℃时,大菱鲆口灌给药剂量25mg/kg BW,每日一次;17℃时,大菱鲆口灌给药剂量22mg/kg BW,每日一次。     

温度、光照、pH值对后棘藻生长及脂肪酸含量的影响

报道了环境因子对富含 EPA (2 0∶ 5ω3)的海洋微藻后棘藻 (Ellipsoidion sp.) 70 - 0 1的生长速度、总脂及脂肪酸含量的影响。结果表明 ,后棘藻具有较快的生长速度和较高的脂肪酸含量 ,总脂含量为 31～ 36 % ,主要脂肪酸为 14∶ 0、16∶ 0、16∶ 1、18∶ 1ω9、18∶ 1ω7、18∶ 2 ω6、2 0∶ 4 ω6、2 0∶ 5ω3。生长的温度范围为 15～ 30℃ ,2 5℃时生长速度最快。温度对总脂含量影响很小 ,但对EPA和 PUFA含量影响较大。在 2 5℃时有最大的 EPA和 PUFA含量。适宜光强为 10 8.75μmolm-2 s-1～ 2 4 4 .15μmolm-2 s-1,在 145.54μmolm-2 s-1时 EPA产率较大。在起始 p H6 .5～ 9范围内 ,p H8.5时有最大的生长速率和总脂含量 ,而 EPA和 PUFA在起始 p H7.5时最大 ,分别占脂肪酸的 18.77%和 2 3.38%。实验条件下后棘藻 EPA产率最大的条件为温度 2 5℃ ,光强 145.54μmolm-2 s-1,p H为 7.5～ 8.5。     

温度对条石鲷幼鱼代谢率、排泄率及窒息点的影响

采用静水密闭式呼吸仪,分别测定了13,18,23,28和33℃5个水温梯度下条石鲷Oplegnat-hus fasciatus幼鱼的代谢率、排泄率及窒息点。结果表明:(1)不同温度条件下,条石鲷幼鱼的代谢率和排泄率差异显著(p<0.05);当温度由13℃升高至28℃时,条石鲷幼鱼的代谢率和排泄率均随之升高;当水温为28℃时,其代谢率和排泄率达最大值,分别为(16.33±0.45)J/(g·h)和(1.03±0.04)J/(g·h),是13℃实验组的6.69倍和5.15倍;与28℃实验组相比,33℃实验组的代谢率和排泄率分别降低了19.04%和15.53%,33℃已超出了条石鲷幼鱼生长的最高适温。(2)实验温度下,条石鲷幼鱼的蛋白质供能比值为37.94%～72.24%,蛋白质是其主要能源物质。(3)条石鲷幼鱼的窒息点为(3.17～3.64)mg/L,并随水温升高而升高。(4)Q10值和蛋白质供能比值的变化特征表明,18～28℃是条石鲷幼鱼的适宜生长温度。     

The potential food poisoning hazard of Vibrio parahaemolyticus in New Zealand Pacific oysters

The level of Vibrio parahaemolyticus was generally very low in Pacific oysters sampled from 4 New Zealand oyster farms between November 1982 and May 1983. Of the 149 samples collected, only one was found to contain greater than the 1000 organisms g^‐1regarded as the maximum allowable by international standards (International Commission on Microbiological Specifications for Foods 1982: Micro‐organisms in Foods, Vol. 2. Academic Press, New York). V. parahaemolyticus was detected in 57% of the oyster samples, but 95% of these contained less than 10 organisms g^‐1. Maximum levels appeared to coincide with high water temperatures at the farm sites. Chilling, freezing, and depuration reduced V. parahaemolyticus numbers in oysters after harvest. However, holding at ambient temperatures (19–25°C) resulted in up to a 35‐fold increase in organism numbers with a maximum after one day. The food poisoning hazard from V. parahaemolyticus in New Zealand‐grown Pacific oysters thus appears to be minimal. Recommendations are made to keep harvested shellfish cool and to chill them as soon as practical.     

杂交鲷和黑鲷幼鱼的代谢率及排泄率比较

杂交鲷是以真鲷为母本,黑鲷为父本的杂交F1代品种,为了比较杂交鲷与黑鲷的代谢特征,采用静水密闭式呼吸仪测定了13、18、23、28、33℃（32℃）5个温度下杂交鲷和黑鲷幼鱼的代谢率及排泄率.结果表明：13~28℃温度下,杂交鲷和黑鲷幼鱼的代谢率、排泄率均随温度的升高而升高,28℃时杂交鲷和黑鲷幼鱼的代谢率、排泄率分别为14.22±0.95、0.39±0.02 J/（g.h）和17.47±0.14、0.43±0.02 J/（.gh）,分别是其13℃时的5.69、4.05倍和4.01、3.73倍;且各温度下黑鲷的代谢率始终高于杂交鲷,前者是后者的1.23~1.73倍;杂交鲷和黑鲷幼鱼分别在32℃和33℃时代谢率比28℃下跌了22.23%和3.83%,证明该温度已分别超出了这2种幼鱼的最高适温;杂交鲷和黑鲷幼鱼28℃时的窒息点溶解氧含量分别为1.94、1.40 mg/dm3,低于真鲷21℃时的窒息点溶解氧含量（2.30 mg/dm3）;O∶N原子比值结果显示,28℃时蛋白质供能比最低,生长积累速度最快,是2种幼鱼的最适温度.综合分析认为,杂交鲷幼鱼具有代谢率显著低于亲本的优点,也继承了父本耐低温的特点,但同时失去了亲本耐高温、耐低氧的特点,并出现了应激反应大等不良性状.     

Distribution of Trace Bioelements in the Subarctic North Pacific Ocean and the Bering Sea (the R/V Hakuho Maru Cruise KH-97-2)

A column concentration-high resolution inductively coupled plasma mass spectrometry (ICP-MS) determination was applied to measure the total dissolved concentrations of Fe, Co, Ni, Cu and Zn in seawater collected from the subarctic North Pacific (~45°N) and the Bering Sea in July–September 1997. Total adsorbable Mn was determined on board by column electrolysis preconcentration and chemiluminescence detection. The vertical profiles for Fe, Ni and Zn were nutrient-like. The deep water concentration of Fe was ~0.5 nM in the northeast Pacific (18°-140°W) and increased to ~1 nM in the northwest Pacific (161°E) and ~2 nM in the Bering Sea (57°N, 180°E). The deep water concentrations for Ni and Zn in the Bering Sea were also 1.3–2 times higher than in the North Pacific. The profiles for Co and Cu were examined in the subarctic North Pacific, and results obtained were consistent with previous reports. There was a significant correlation between the concentrations of Co and Mn except for surface mixed layer. The profiles for total adsorbable Mn were similar to the reported profiles for total dissolvable Mn. The deep water concentration of Mn in the Bering Sea was also 4 times higher than in the North Pacific. Iron and zinc were depleted in surface water of the subarctic North Pacific. The relationship between these trace elements and nutrients suggests that these elements could be a limiting factor of phytoplankton productivity. In the Bering Sea, surface water contained ~0.3 nM of Fe. The Zn concentration, which was less than the detection limit in surface water, increased at shallower depths (~30 m) compared with the subarctic North Pacific. These results imply a higher flux of Fe and Zn to surface water in the Bering Sea. This in turn may cause the ecosystem in the Bering Sea characterized by a dominance of diatoms and high regenerated production.     

Depuration dynamics of oysters (Crassostrea gigas) artificially contaminated by Salmonella enterica serovar Typhimurium

The State of Santa Catarina produces the greatest quantity of edible mollusks in Brazil. To guarantee sanitary qualify, mollusk cultures should be monitored for contamination by pathogenic microorganisms. A self-purification or "depuration" system that eliminates Salmonella enterica serovar Typhimurium contamination from oysters has been developed and evaluated. The depuration process occurred within a closed system, in which 1000 L of water was recirculated for 24 h. The water was sterilized with ultraviolet (UV) light, chlorine, or both together. Oysters (Crassostrea gigas) artificially contaminated with S. typhimurium were harvested every 6 h. Samples of oyster tissue were excised and both the presence and numbers of bacteria were determined. Combined UV light and chlorine treatments resulted in total elimination of bacteria within 12 h. Polymerase chain reaction detected bacteria in water exposed to the three treatments. This pioneering study is the first of its kind in Brazil and represents a major contribution to commercial mollusk culture in this country.     

Bioaccumulation and depuration of Zn and Cd in mangrove oysters (Crassostrea rhizophorae, Guilding, 1828) transplanted to and from a contaminated tropical coastal lagoon

In order to study Zn and Cd accumulation and depuration, a set of oysters, Crassostrea rhizophorae, were transplanted to a metal contaminated coastal lagoon and another one was harvested there and transplanted to a non-polluted site. C. rhizophorae oysters and Perna perna mussels native from both sites were collected in order to monitor variability of metal concentration in resident populations. After three months exposure, oysters transplanted to the polluted site accumulated fourfold Zn (307-1319 microgg(-1)) without reaching the concentration level of resident oysters (9770 microgg(-1)). Cadmium concentrations had a slight but significant decrease during the same period (1.25-0.54 microgg(-1)). Oysters transplanted to the non-polluted site, showed threefold Zn depuration (6727-2404 microgg(-1)), while Cd had no significant variation (0.90-1.45 microgg(-1)). Results showed that transplanted oysters do not reach heavy metal concentrations in indigenous populations suggesting transplanted organisms would be better used to evaluate bioavailability instead of environmental concentrations.     

盐度对二倍体和三倍体长牡蛎呼吸和排泄的影响

采用室内实验的方法研究了盐度对二倍体(2n)和三倍体(3n)长牡蛎(Crassostrea gi-gas)呼吸和排泄的影响。实验的盐度(S)梯度为15,20,25,30,35共5个梯度,实验牡蛎的规格为,2n:W(软体部干质量,单位为g)=0.347±0.071 g;3n:W=0.301±0.099g。实验结果表明:盐度对二倍体和三倍体长牡蛎的呼吸和排泄有显著影响。在实验的盐度范围内,随着盐度的升高,二倍体和三倍体长牡蛎的耗氧率逐渐增大,盐度与耗氧率的关系可表示为,2n:Ro[mg/(g·h)]=0.0142S~(1.219),3n:Ro[mg/(g·h)]=0.0085S~(1.391);随盐度的升高,排氨率逐渐增大,当S为35时,二倍体和三倍体长牡蛎的排氨率略有下降,在实验的盐度范围内,盐度与排氨率的关系可表示为,2n:RA[μg/(g·h)]=-12.25+2.902S-0.0573S~2;3n:RA[ug/(g·h )]=-39.39+3.882S-0.06S~2。在实验的盐度范围内,二倍体和三倍体长牡蛎耗氧率的差异未达到显著水平(P>0.05),而排氨率的差异则有所不同,当S为15～20时,二倍体和三倍体牡蛎的排氨率差异达到显著水平(P<0.05),而S为25～35时,其差异不显著(P>0.05)。     

早第四纪西太平洋底栖有孔虫群与大洋深层水环流演化的关系

选取赤道西太平洋ODP 807站位(3°36.42′N,156°37.49′E,水深2 803.8m,岩心长822.9m)26.27～43.02mbsf层段中的底栖有孔虫进行研究,以便了解早更新世2.5～1.6Ma BP时期古生产力和深水环流的变化。结果显示,这一时期底栖有孔虫堆积速率(BFAR)、表生种和内生种比值(E/I)、Uvigerina spp.百分含量和有机碳百分含量(TOC%)等替代指标反映了西太平洋古生产力总体上呈现冰期高、间冰期低的特点,而其中Bulimina alazanensis的丰度变化则相反,反映了该种有可能更适合温暖、低营养的底层水环境。2.5～1.6 MaBP时期底栖有孔虫在丰度上以Uvigerina spp.为主,指示了早更新世西太平洋深层水受北部水团的控制更强。     

Effects of polynuclear aromatic hydrocarbons on fishes and shellfish: An overview of research in virginia

This paper discusses the following topics related to polynuclear aromatic hydrocarbon pollution in estuaries: (1) the use of oysters (Crassostrea virginica), hard clams (Mercenaria mercenaria) and brackish water clams (Rangia cuneata) in residue monitoring; (2) the effects of elevated PAH residues on oyster condition; (3) three years of field studies relating PAH sediment contamination to abnormalities in fishes; and (4) laboratory bioassays for effects and bioconcentration modeling. Oysters, hard clams and Rangia have been shown, from 3 years of field studies, to be good monitors of pollution inputs as one proceeds along salinity gradients from 25‰ to 0·5‰. Effects of increased body burdens of PAHs are shown by a lowering of the oysters' condition index, as measured by lipid levels. Fishes inhabiting the Elizabeth River, VA, which is highly contaminated with PAHs, have abnormalities (cataracts, skin lesions, abnormal fins, etc.). These abnormalities have higher incidence in regions of the river where the sediments are more heavily contaminated. Laboratory studies utilizing contaminated sediments have reproduced some of the abnormalities observed in the field. Bioconcentration of PAHs from sediments has been studied with oysters and hard clams. Oysters generally accumulate three times the body burdens of clams exposed to the same suspensions. A faster depuration rate (k₂) for clams appears to be responsible for the higher equilibrium body burden of oysters.