条纹密鲈卵黄蛋白原基因的克隆与检测

采用RT-PCR方法克隆并分析了条纹密鲈卵黄蛋白原(VTG)和β-肌动蛋白(β-actin)cDNA部分序列。获得的VTG cDNA序列片段长3 464 bp,全部处于编码区,编码1 150个氨基酸;β-actin cDNA序列片段长1 253 bp,编码375个氨基酸。使用活体与离体的实验方法,检测了VTG mRNA 转录情况,并以此评价雌二醇(E₂)、辛基酚(OP)、镉(Cd²⁺)和全氟辛烷磺酸类化合物(PFOS)引起的雌激素效应。结果显示,E₂和OP在活体和离体实验中均能剂量依赖性地诱导VTG mRNA表达。Cd²⁺仅在活体实验低剂量组诱导VTG mRNA表达,PFOS在活体和离体实验的各个浓度组均未见显著的VTG mRNA表达。结果表明,所诱导的雌激素效应强弱的排列顺序为E₂>OP>Cd²⁺。Cd²⁺的雌激素效应活体和离体实验的结果不一致,推测Cd²⁺引起雌激素效应的机理可能和E₂不同。条纹密鲈VTG cDNA对环境激素敏感,适合作为监测环境激素的生物标志物。     

三疣梭子蟹体内镉的蓄积特性及相应防控

应用半静态双箱模型室内模拟实验, 研究三疣梭子蟹(Portunus trituberculatus)体内镉(Cd)的蓄积特异性; 并通过分析钙离子(Ca²⁺)对三疣梭子蟹可食用部位镉(Cd)富集和释放影响, 提出三疣梭子蟹 Cd 污染防控建议。通过双箱动力学模型对三疣梭子蟹体内 Cd 含量变化进行非线性拟合, 得到富集速率常数 k₁和排出速率常数 k₂, 进而得到生物富集系数(BCF)和生物学半衰期(B_1/2)。结果显示, 1 μg/L、5 μg/L 和 50 μg/L Cd 暴露组三疣梭子蟹肝胰腺组织对 Cd 的 BCF 明显高于肌肉组织, 三疣梭子蟹肝胰腺组织中 BCF 和 k1 均随水体中 Cd 浓度的增加而增加, 1 μg/L, 5 μg/L 和 50 μg/L Cd 暴露组对 Cd 的 BCF 分别为 12.16、112.77 和 260.11; 肌肉组织中吸收速率常数 k₁ 与释放速率常数 k₂ 均随水体中 Cd 浓度的增加而增加, 由低到高 Cd 暴露组对 Cd 的 BCF 分别为 1.85、2.45 和 1.97。各浓度暴露组肝胰腺中 Cd 暴露风险指数(THQ)除 1 μg/L 组外, 均大于 1, 存在严重健康暴露风险; 各浓度暴露组肌肉中的 THQ 均小于 1, 没有明显的健康暴露风险。另外, Ca²⁺对三疣梭子蟹肝胰腺和肌肉中 Cd 富集和释放影响的实验结果表明, Ca²⁺的加入能够有效降低三疣梭子蟹肝胰腺和肌肉对 Cd 的富集, 并促进肝胰腺对 Cd 的释放。本研究结果为三疣梭子蟹 Cd 污染防控和食用方案的提出提供了理论基础。     

苯并[a]芘、菲在缢蛏体内的生物富集与释放

为了研究苯并[a]芘(Bap)、菲PHE在缢蛏体内的富集及释放过程的动力学特征,通过双箱动力学模型对富集(15 d)与释放(9 d)过程进行非线性曲线拟合,获得缢蛏对BaP、PHE的吸收速率常数k₁、释放速率常数k₂、生物富集因子BCF、平衡状态下生物体内BaP含量C_Amax、生物学半衰期B_1/2。结果显示,缢蛏对BaP的富集能力高于PHE,BaP增加幅度分别为0.45 ng/(kg·d)(40 μg/L实验组)、0.33 ng/(kg·d)(20 μg/L实验组)、0.23 ng/(kg·d)(10 μg/L实验组);PHE增加幅度分别为0.33 ng/(kg·d)(30 μg/L实验组)、0.25 ng/(kg·d)(20 μg/L实验组)、0.18 ng/(kg·d)(10 μg/L实验组)。BaP、PHE的富集、清水释放均为前期迅速,后期缓慢。缢蛏对BaP、PHE的k₁范围分别为0.39~0.52,0.30~0.43,平均值分别为0.44和0.36,均随BaP、PHE暴露浓度的增大而减少;k₂范围分别为0.001 6~0.001 7,0.002 8~0.003 3,平均值分别为0.001 6和0.003 0,无明显的变化趋势;BCF范围分别为243.96~306.28,105.73~130.85,平均值分别为268.18和118.57,均随BaP、PHE暴露浓度的增大而减少;C_Amax范围分别为3 062.76~9 758.25 μg/kg,1 308.54~3 171.84 μg/kg,平均值分别为5 969.08和2 287.71 μg/kg;B_1/2范围分别为407.73~433.22 d,210.68~248.06 d,平均值分别为421.20和232.04 d,均随BaP、PHE暴露浓度的增大而增大。     

龙须菜对铜、镉的富集特征

通过以人工培育的龙须菜在低浓度Cu²⁺、Cd²⁺污染水体中对铜(Cu)、镉(Cd)富集与释放的模拟实验,探索龙须菜对Cu、Cd污染水体的修复作用。富集实验结果表明,龙须菜对Cu²⁺、Cd²⁺有较强的富集能力,龙须菜中Cu、Cd的含量与水体中Cu²⁺、Cd²⁺的浓度以及暴露时间呈显著正相关关系。在Cu²⁺、Cd²⁺共存的环境中,龙须菜Cu、Cd的含量均比Cu²⁺、Cd²⁺单独存在的环境中高。应用双箱模型,对富集和释放实验的数据进行拟合,得到龙须菜富集Cu²⁺、Cd²⁺的速率常数和释放速率常数。拟合结果显示,龙须菜对Cu的富集能力高于对Cd的富集能力。龙须菜的富集能力随水体中Cu²⁺、Cd²⁺浓度的升高而降低。释放实验结果表明,离子交换和络合是龙须菜富集Cu²⁺、Cd²⁺的重要途径,被龙须菜吸附的Cu²⁺、Cd²⁺通过解吸能重新被释放。     

镉诱导鲫肝细胞内Ca2+-ATP酶与金属硫蛋白的表达

研究了镉诱发鲫肝细胞相关的胞内游离钙离子变化,以及Ca²⁺-ATP酶及金属硫蛋白表达量的变化。试验分为对照组、5、10、15、20 μmol/L CdCl₂ 5个组。Ca²⁺用Fura-2/AM方法检测,试验后24 h用荧光倒置显微镜观察细胞内游离钙离子变化;分光光度法检测Ca²⁺-ATP酶;石墨炉—原子分光光度法检测了细胞内镉离子浓度;免疫酶联法(ELISA)检测了金属硫蛋白(MT)含量。结果显示,镉可导致细胞存活率下降,具有一定的毒性。镉离子引起胞内Ca²⁺荧光强度和Ca²⁺-ATP酶活性增加(P＜0.01)。随镉浓度升高,处理组Ca²⁺-ATP酶浓度活性分别是对照组的4.52、6.73、6.68、7.19、6.18倍;暴露24 h后各组细胞内镉离子均有上升,其中5 μmol/L组最高,达(2.045±0.322) μmol/L;各处理组金属硫蛋白(MT)含量增高(P＜0.01),且5 μmol/L低浓度组MT增幅最大,达17.15%。结果提示,镉诱导下细胞内Ca²⁺升高,MT表达量上升,且MT可螯合进入细胞内的镉离子,这种螯合可能是降低镉毒理作用的机制之一。     

蛋白水解肽-Fe2+配合物对克氏原螯虾体内Cd2+的脱除效果

为探讨克氏原螯虾体内重金属Cd²⁺残留的脱除方法,采用基础饲料中添加制备的蛋白水解肽-Fe²⁺配合物(TPH-Fe²⁺)进行饲喂,检测螯虾不同组织器官中Cd²⁺含量变化情况。结果显示,染毒后螯虾不同器官中Cd²⁺富集量依次为内脏团>肠>鳃>腹部肌肉>螯足肌肉,且在0~12 d自然净化过程中,无显著性下降趋势。添加400、800和1 200 mg/kg TPH-Fe²⁺饲喂螯虾,内脏团、鳃、肠及腹部肌肉中Cd²⁺含量均有不同程度下降;饲喂12 d后,螯虾不同器官中Cd²⁺脱除率为肠>内脏团>鳃>腹部肌肉,脱除率分别为40.60%、36.13%、33.36%和10.15%;TPH-Fe²⁺对螯虾螯足肌肉中Cd²⁺含量无显著性影响。研究表明,蛋白水解肽-Fe²⁺配合物能有效脱除螯虾体内Cd²⁺残留,可作为一种螯虾养殖饲料添加剂在基础饲料中加以应用。     

Investigation into the possible role of androgens in the induction of hepatic vitellogenesis in the European eel:in vivo andin vitro studies

Changes in the levels of plasma vitellogenin (Vg), estradiol (E₂) and testosterone (T) were examined following gonadal development induced by carp gonadotropin treatment (cGTH) of freshwater female yellow and silver eels (Anguilla anguilla L.). The animals received injections of cGTH (250 μg kg⁻¹ body weight) or saline vehicle three times a week, for 6 to 8 weeks. No effect of vehicle was observed. Steroidogenic activity of the ovary was stimulated by cGTH treatment as shown by the increase in circulating steroid levels in both stages. However, the responses of T, E₂ and Vg differed according to the stage of development of eels. At the yellow stage, the initial steroid plasma levels were undetectable (< 0.01 ng ml⁻¹) before treatment and ovarian steroidogenic activity was slightly stimulated following cGTH treatment; steroid levels reached their highest values after 3 weeks and 6 weeks of treatment for E₂ (0.62 ± 0.13 ng ml⁻¹ and T (0.33 ± 0.30 ng ml⁻¹), respectively. The cGTH treatment slightly increased plasma Vg levels (0.2–0.7 μg ml⁻¹ during the experiment compared with the initial values of the group. At the silver stage, the initial steroid levels were detectable (0.7 ng ml⁻¹ for E₂ and 0.1 ng ml⁻¹ for T); cGTH treatment did not significantly increase plasma E₂ level which remained at initial levels. Nevertheless, plasma T levels dramatically increased from 0.1 to 3 ng ml⁻¹ and peaked after 1 or 2 weeks of cGTH treatment; a rapid increase in plasma Vg levels occurred, reaching its highest value at 5 mg ml⁻¹ after 3 weeks of treatment. Thus, the steroid kinetic profiles in relation to the appearance of Vg in the plasma following cGTH treatment was closely related to androgen levels and there was a strong vitellogenic response induced by chronic cGTH treatment. In order to test if androgens could be implicated in the vitellogenic response, we evaluated the potencies of various androgens (testosterone and 5α-androstane-3β,17β-diol)in vivo andin vitro, associated with E₂ to induce the production of Vg.In vitro experiments showed that Vg synthesis was induced by high doses (10⁻⁶ to 10⁻⁵ M) of androgen in the eel. Tamoxifen totally inhibited the action of androgens suggesting that androgens were acting through binding to the E₂ receptor.In vivo, androgens given alone at 50 μg kg⁻¹ 3 times a week for 1 months had no significant effect on plasma Vg levels. In addition, E₂-androgen cotreatment showed that the presence of androgen did not modify the vitellogenic response induced by E₂.     

臭氧杀菌结合气调包装对缢蛏的保鲜效果

以缢蛏为研究对象,通过臭氧杀菌及不同气调包装处理,测定其在(0±0.5) ℃冷藏过程中的菌落总数、理化和感官等指标的变化,评价臭氧杀菌结合气调包装的保鲜效果。臭氧处理浓度为1 mg/L,包装条件分别为低氧气调包装(60% CO₂+30% N₂+10% O₂)、无氧气调包装(60% CO₂+40% N₂)、空气包装(对照)、低氧气调包装(60% CO₂+30% N₂+10% O₂)与臭氧处理复合、无氧气调包装(60% CO₂+40% N₂)与臭氧处理复合、臭氧处理包装。结果显示:0 ℃下缢蛏在空气包装下贮藏4 d和臭氧处理包装下贮藏8 d后菌落总数分别达到1.76×10⁷ cfu/g和1.14×10⁷ cfu/g,在有氧气调包装条件下和无氧气调包装调节下贮藏10 d后菌落总数分别达到1.87×10⁷ cfu/g和1.03×10⁷ cfu/g,超过规定的卫生标准;而有氧气调包装结合臭氧处理可使缢蛏的货架期达到12 d(9.33×10⁶ cfu/g),无氧气调包装结合臭氧处理可使缢蛏货架期延长至14 d(8.74×10⁶ cfu/g)以上。各处理组的TVB-N、K值、感官评分、pH变化也均与贮藏时间相关(P<0.05),并且气调包装结合臭氧处理组样品在冷藏期间的TVB-N、pH、K值和感官等指标均优于单独的气调包装或臭氧处理。相对于其它实验组,臭氧处理结合无氧气调包装组保鲜效果最好,样品在货架期末(14 d)TVB-N达到14.952 mgN/100 g,K值达到55%,感官评分达到5分,仍处于中等新鲜水平或可接受程度。总体结果表明,臭氧处理结合气调包装能有效延长冷藏缢蛏的货架期。     

单环刺螠生物扰动对沉积物-水界面氮磷扩散通量的影响

为了解单环刺螠生物扰动作用对沉积物-水界面氮磷扩散通量的影响及其持续性,于2020年11—12月,采用室内实验生态学的方法,设置低密度 (LD,500 尾/m²)、中密度 (MD,2 500 尾/m²)、高密度 (HD,8 300 尾/m²)处理组和1个对照组 (CO,0 尾/m²),进行了2 d为一个实验时段,为期20 d的模拟实验。结果显示,处理组溶解无机氮(DIN)扩散通量变化范围为10.6~765.3 μmol/(m²·d),与对照组相比,低、中、高处理组的DIN通量分别提高了57%、76%、88%。NH₄⁺是DIN的主要贡献者,对DIN的贡献在低、中、高处理组中分别占55%、65%和80%。与对照组相比,低、中、高密度组的平均NH₄⁺通量分别提高了39%、111%和257%,与低、中密度处理组平均NH₄⁺通量相比,高密度处理组分别提高了43.7%和23.6%。在第2~10天,NH₄⁺通量处于持续增加的趋势。处理组PO₄³⁻通量变化范围为−7.85~6.42 μmol/(m²·d),第2~6天,处理组PO₄³⁻通量持续增加。研究表明,单环刺螠的生物扰动能够持续地促进DIN由沉积物向水体中扩散,且存在明显的密度效应。研究结果将为深入认识单环刺螠在水层-底栖系统耦合过程中的生态作用提供基础数据。     

三氯生对雌性黄河鲤激素效应及其机制的研究

为了探讨三氯生(TCS)对雌性鱼类性激素的影响及其机制。通过半静态水质接触染毒法对雌性黄河鲤进行染毒,设置对照组和三个不同浓度组(0.04 mg/L、0.08 mg/L、0.16 mg/L)的TCS处理组,采用酶联免疫(ELISA)和实时荧光定量PCR(RT-PCR)法检测各组雌性黄河鲤血清睾酮(T)和雌二醇(E₂)的分泌水平及其卵巢中促性腺激素释放激素(CGnRH-ii-2)和雌激素受体(Er)的mRNA表达水平。结果显示：各浓度组的T水平无显著性差异(P>0.01),而0.16 mg/L的TCS能使黄河鲤血清中的E₂含量及E2/T显著性升高(P<0.05, P<0.01)；TCS各浓度组卵巢中CGnRH-ii-2 mRNA水平显著下降(P<0.01),而0.08和0.16mg/L的TCS处理组Er mRNA水平显著升高(P<0.05,P<0.01)。结果表明：TCS具有潜在雌激素效应,其机制与雌激素受体和促性腺激素释放激素基因表达调控相关。     

Effects of dietary phospholipid level in cobia (<Emphasis Type="Italic">Rachycentron canadum</Emphasis>) larvae: growth,survival, plasma lipids and enzymes of lipid metabolism

A study was conducted to determine the effects of dietary phospholipid (PL) levels in cobia (Rachycentron canadum) larvae with regard to growth, survival, plasma lipids and enzymes of lipid metabolism. Fish with an average weight of 0.4 g were fed diets containing four levels of PL (0, 20, 40 and 80 g kg⁻¹dry matter: purity 97%) for 42 days. Final body weight (FBW), weight gain (WG) and survival ratio were highest in the 8% PL diet group and mortality was highest in PL-free diet group. We examined the activities of lipoprotein lipase (LPL) and hepatic lipase (HL) in liver, lecithin-cholesterolacyltransferase (LCAT) in plasma as well as plasma lipids and lipoprotein. LCAT activity showed a decrease of more than two-fold in PL-supplemented diet groups compared with the PL-free diet group. HL activity was highest in the 8% PL diet group and the other three groups showed no difference. LPL activity was significantly higher in the PL-supplemented diet groups than in the PL-free diet group. The dietary intervention significantly increased plasma phospholipids and total cholesterol (TC) levels, and the higher free cholesterol (FC) level contributed to the TC level. However, the fish fed PL exhibited a significantly decreased plasma triglyceride (TG) level. The lipoprotein fractions were also affected significantly by the PL. The PL-supplemented diet groups had significantly higher high-density lipoprotein (HDL) compared with the PL-free diet group, but showed a marked decrease in very low-density lipoprotein (VLDL). The results suggested that PL could modify plasma lipoprotein metabolism and lipid profile, and that the optimal dietary PL level may well exceed 80 g kg⁻¹ for cobia larvae according to growth and survival.     

Induction of Out-of-Season Spawning of Pikeperch, Sander Lucioperca (L.)

Pikeperch were induced to spawn 3 months prior to the natural spawning period through photothermal and hormonal stimulation. Females (five specimens in each group) were stimulated with injection of human chorionic gonadotropin (hCG) once (200 IU kg^–1), twice (200 IU kg^–1, second dose after 48 h–400 IU kg^–1) or three times (200 IU kg^–1, after 24 h–200 IU kg^–1 and after another 24 h–200 IU kg^–1). The control group was injected once with 0.9% NaCl. The males were stimulated with a single hormone dose of 200 IU kg^–1. Eggs were obtained from all the hormonally treated fish. None of the control group females, which were only stimulated photothermally, ovulated any eggs. The time of ovulation was 66–71 h following the first injection, and the eggs viability until the eyed stage (from 71.5 to 77.5%) did not depend on the number of hormone doses (P > 0.05). The out-of-season spawning method described in this paper could be used to provide pikeperch larvae for intensive culture systems (recirculating water systems) before natural spawning season and to produce larger-sized pikeperch fingerlings for stocking.     

三种水生动物细胞系对两株蛙病毒敏感性的比较

利用3个不同物种的水生动物细胞系,包括爪蟾肾细胞系(A6)、大鲵胸腺细胞系(GSTC)和鲤上皮瘤细胞系(EPC),分别用沼泽绿牛蛙蛙病毒(RGV)和大鲵蛙病毒(ADRV)感染,进一步研究细胞病变显微形态、病毒滴度、细胞病变与不同感染时间的相关性等。结果显示,在光镜下可见感染病毒的细胞发生病变,A6和EPC细胞肿胀或破裂;GSTC细胞收缩或聚在一起形成多层。同种水产动物细胞系对不同蛙病毒的敏感性不同,在A6、EPC和GSTC细胞中,RGV的滴度分别为10~(3.6)、10~(5.9)和10~(6.6) TCID_(50)/m L;ADRV的滴度分别为10~(4.3)、10~(5.4)和10~(6.1) TCID_(50)/m L,表明GSTC细胞系对两种蛙病毒都更敏感。研究为后续蛙病毒致病机理提供了有用的信息和重要实验材料。     

鲢、鳙对三角帆蚌池塘藻类影响的围隔实验

以浙江金华汤溪威旺养殖基地的三角帆蚌养殖水体为研究对象,通过围隔实验比较研究了单养鲢、鳙和三角帆蚌的池塘浮游植物密度、生物量和优势种(属)组成等的差异,以及养蚌池混养鲢鳙对水体浮游植物密度、生物量以及优势种变化的影响。结果表明,养蚌(10#)围隔的浮游植物平均密度和生物量均显著高于高密度鲢(12#)围隔(P<0.05),其蓝藻数量及生物量显著高于高密度鲢(12#)和低密度鳙(13#)围隔(P<0.05),绿藻数量则显著低于低密度鲢单养(11#)围隔(P<0.05)。在鱼蚌混养的情况下,单养蚌(10#)围隔浮游植物平均数量显著高于鲢-蚌混养(15#,16#)和鳙-蚌混养(17#,18#)围隔(P<0.05),其蓝藻数量及生物量极显著高于鲢-蚌混养(15#,16#)或鳙-蚌(17#,18#)围隔(P<0.01),其绿藻数量显著低于混养高密度鲢(16#)或低密度鳙(17#)的混养围隔(P<0.05)。研究结果充分说明,鲢、鳙和三角帆蚌三者对水体藻类组成的影响有别,三角帆蚌养殖池中适当混养鲢或鳙可以有效控制蓝藻(铜绿微囊藻)的生长,促进绿藻(四尾栅藻)的生长,并最终有利于三角帆蚌的养殖,混养鲢密度的增加有利于控制藻类生长,而鳙密度的增加促进了裸藻等中大型藻类的生长。     

Influence of temperature on the hatching of eggs of Diplectanum aequans,a parasite of sea bass

This study deals with the influence of temperature on the hatching of eggs of Diplectanum aequans, a branchial ectoparasite of sea bass (Dicentrarchus labrax). At temperatures of 20 °C, 25 C and 30 °C hatching takes place within a few days of laying, whereas at 15 C and 10 C it occurs respectively between the 7th and the 12th day and between the 11th and the 19th day. No hatching has been observed at 5 C. Development is not completely inhibited at 5 C as the eggs can, at least partially, go on maturing and will subsequently hatch as soon as higher temperatures are encountered.     

杂色鲍DAD1的克隆及在发育、弧菌感染、高温和缺氧下的表达分析

抗细胞凋亡因子(DAD1)是细胞凋亡的负调控因子。在杂色鲍转录组测序的基础上,通过RACE的方法,获得了杂色鲍DAD1基因的全长c DNA,命名为HdDAD1。该序列全长553 bp,开放阅读框339 bp,编码112个氨基酸。编码蛋白具有保守的DAD功能域和3段跨膜区。实时定量PCR结果表明,HdDAD1在杂色鲍所检测组织中均有表达,消化道、鳃、血细胞、粘液腺和肾脏中表达量最高。同样,HdDAD1在发育各阶段均有表达,幼虫阶段表达量最高,原肠胚次之,其他胚胎发育阶段和稚鲍表达量最低。HdDAD1能够响应细菌感染、高温和缺氧应激。在弧菌注射12 h后,表达量显著上升。当水温由最适的25°C上升到28°C时,HdDAD1表达量升高;在31°C持续4和96 h时HdDAD1表达量显著上升。在低氧处理4和96 h时,HdDAD1的表达量也显著上升。     

铜铸熟若蟹中麻痹性毒素成分的分离和鉴定

在分析了日本珊瑚扇蟹铜铸熟若蟹甲壳组织和内脏组织中毒性含量的基础上,对毒素提取液进行分离纯化,并通过液相色谱法对其毒素种类进行分析。毒性分析结果显示,毒蟹个体的含毒量在37 500~116 000 MU范围,远远超过成人中毒致死量(5 000 MU),但个体间的毒含量有较大差异;毒蟹个体的甲壳组织的比毒性(909~1 610 MU/g)总体高于内脏组织(111~576 MU/g)。Bio-Gel-P₂凝胶柱层析纯化结果显示,粗毒素提取液通过反复纯化可以达到纯化目的,毒素的比毒性从4.8 MU/mg上升到30 MU/mg左右;毒素进一步通过Bio-Rex 70离子交换柱层析的分离纯化结果显示,毒素中约有9%为膝沟藻毒素群(GTXs,麻痹性毒素中的一类)。高效液相色谱分析结果显示,膝沟藻毒素群的主要成分为GTX3和GTX2,并含有少量的dcGTX2和dcGTX3。     

缺刻缘绿藻溶血磷脂酰乙醇胺酰基转移酶(LPEAT)的基因克隆与特征分析

缺刻缘绿藻三酰甘油(TAG)中花生四烯酸(Ar A)占其总脂肪酸含量的68.0%。为了弄清Ar A是如何被优先地用于合成TAG,鉴于Lands循环是通过改变膜脂的脂肪酸组成进而影响TAG的脂肪酸组成,本研究选择在Lands循环中起关键作用的溶血磷脂酰乙醇胺酰基转移酶(LPEAT)作为突破口。运用反转录PCR与3′-及5′-c DNA末端快速扩增技术,自缺刻缘绿藻(Myrmecia incisa Reisigl)中克隆到MiLPEAT;它的c DNA序列全长1303 bp,其中,5′-非翻译区(UTR)长129 bp,3′-UTR长193 bp,开放阅读框长981 bp,编码326个氨基酸残基;以缺刻缘绿藻基因组DNA为模板扩增得到该基因长为1871 bp的DNA序列;这两序列的比对结果显示,MiLPEAT含有6个内含子,将其开放阅读框(ORF)分割成7个外显子。通过多序列比对及生物信息学分析,发现MiLPEAT存在一个磷酸酰基转移酶结构域Pls C,并含有LPEAT家族所具有的NH(x)4D、FPEGT等4个特征性模体;Wolfpsort等在线预测结果以及MiLPEAT羧基端存在的双赖氨酸模体"KKxx",暗示它可能位于内质网并参与分泌途径。基于不同植物LPEAT的氨基酸序列所构建的邻接聚类图表明,MiLPEAT因与2型LPEAT有不同的序列特征而形成不同的分支,但却与1型LPEAT聚类在一起,推测它们的功能可能更近似。通过荧光定量PCR检测,发现MiLPEAT的基因转录量在氮饥饿8 h时显著(P0.05)增加;与其变化相应的溶血磷脂酰乙醇胺(LPE)相对丰度却极显著地(P0.01)减少49%,但磷脂酰乙醇胺(PE)相对丰度的增加却不显著;推测在氮饥饿过程中增加的磷脂酰乙醇胺(PE)可能被磷脂:二酰甘油酰基转移酶作用以合成为TAG,致使缺刻缘绿藻TAG含量的增加。     

温度对蜕壳后期三疣梭子蟹能量代谢酶活力的影响

为研究温度对三疣梭子蟹雌蟹钙化过程中丙酮酸激酶(PK)、己糖激酶(HK)和琥珀酸脱氢酶(SDH)活力的影响,在实验室条件下设18、22、26 ℃ 3 个温度水平,分别在梭子蟹蜕壳后1、2、8、16 h及完全硬化5个时间点取样,测定其肝胰脏、肌肉和鳃中HK、PK、SDH的活力。结果显示:①与22 ℃条件下相比,高温(26 ℃)和低温(18 ℃)下三疣梭子蟹肌肉中PK的活力在蜕壳后1～8 h明显升高,说明高温和低温条件下梭子蟹肌肉中的糖酵解速率加大;而肝胰脏和鳃中的PK活力的峰值出现在梭子蟹蜕壳后1～2 h,表明蜕壳后1～2 h这2种组织中有较大的糖酵解速率;②3个温度水平下,梭子蟹肝胰脏中HK的活力随钙化过程的进行而降低,蜕壳后1～16 h的活力显著高于完全钙化时的活力,说明蜕壳后的梭子蟹肝胰脏对葡萄糖的利用能力逐渐减弱,而其鳃中HK活力的变化趋势与肝胰脏中相反,说明梭子蟹的鳃对葡萄糖的利用能力随钙化过程的进行而提高,这种差异可能与不同组织在梭子蟹钙化过程中对葡萄糖的利用能力不同有关;③梭子蟹肝胰脏中SDH的活力在3个实验温度下蜕壳后16 h内呈逐渐升高的趋势,说明肝胰脏在钙化过程中三羧酸循环作用逐渐加强。此外,其肌肉和鳃组织中SDH的活力在3个实验温度下的峰值均出现在前8小时,并且低温(18 ℃)的峰值明显低于高温(26 ℃),说明在这段钙化时间中,相对于低温而言,梭子蟹的肌肉和鳃中有氧代谢的加强在高温条件下更显著。在钙化过程中,低温条件下三疣梭子蟹的糖酵解作用没有明显的变化,而三羧酸循环有较明显的减弱趋势,其中三疣梭子蟹肌肉和鳃中SDH的活力明显低于高温条件,表明低温确实可以延长其蜕壳后的软壳时间。     

Frequent occurrence of the tetrodotoxin-bearing horseshoe crab <Emphasis Type="Italic">Carcinoscorpius rotundicauda</Emphasis> in Vietnam

Tetrodotoxin (TTX) was detected by HPLC and LC-MS/MS in specimens of the horseshoe crab Carcinoscorpius rotundicauda collected from Tan Hai village, Vung Tau province, Vietnam, where cases of poisoning due to the consumption of horseshoe crab have frequently been reported. The soft tissue from 10 out of the 12 specimens analyzed showed considerable levels of TTX, making them unsafe for human consumption (81.2 ± 50.3 MU/g). Paralytic shellfish poisoning (PSP) toxins were also detected in all of the specimens, but the levels were low. These findings show that the frequency of occurrence of C. rotundicauda specimens with a high level of TTX is significantly high, and that the TTX is responsible for the food poisonings caused by the consumption of C. rotundicauda in this area.