北海区海洋生态灾害的主要类型及分布现状研究

本文将海洋生态灾害定义为局部海域一种或少数几种海洋生物数量过度增多引起的海洋生态异常现象,包括赤潮、绿潮、水母旺发和外来种入侵等,根据相关研究及调查资料,探讨了北海区赤潮、绿潮、水母、外来生物入侵等生态灾害发生特点及趋势。结果表明,北海区赤潮和绿潮灾害频发,影响面积较大,渤海北部秦皇岛附近海域赤潮灾害严重,黄海西部山东半岛近岸海域浒苔绿潮灾害严重;水母灾害呈上升趋势,对人体健康威胁较大,北海区滨海城市都曾发生过水母蛰伤致死案例;黄河三角洲区域米草和泥螺入侵扩展速度较快。面对这些海洋生态灾害巨大威胁,北海区亟需加强海洋生态灾害防控研究。     

秋季降温期水温和饵料量对沙蜇无性繁殖的影响

20世纪末以来,沙蜇在东亚水域频繁暴发,不仅影响正常的渔业生产活动,也给海洋生态系统健康带来极大危害。在室内模拟秋季降温条件,研究了不同水温（4种降温条件）与饵料量（0.42、1.25、和4.2 μg C螅状体^-1d^-1）对沙蜇螅状体足囊繁殖与横裂生殖的影响。结果显示：1）秋季降温速度快慢导致的积温差异对沙蜇螅状体生成足囊数有显著影响（P < 0.001）,积温越大,螅状体生成的足囊数量越多,发现两者具有较好的线性关系（y=142.59x+208.39;R²=0.967）,低积温条件下的足囊萌发也较少;2）饵料量对螅状体无性繁殖的影响是有一定阈值范围的,在一定饵料量范围内,螅状体生成的足囊数量随饵料量的增加而增加,而超过一定阈值范围,过剩的饵料影响水质对沙蜇螅状体反而产生负面影响。3）秋季新繁育出来的当龄沙蜇螅状体可在越冬前发生横裂生殖,但横裂生殖的螅状体比例和放碟数量均较少。试验结果说明,全球变化背景下,积温升高、饵料量小幅增加均可能导致沙蜇秋季有性繁殖的当龄螅状体在越冬前生成更多的足囊,促进诱发翌年水母暴发。     

渤海水母体细菌的微生态分布及弧菌生物学特性

采用稀平板法对我国辽宁渤海海域水母体中细菌的微生态分布进行了考察,结果表明,在渤海水母体中各部位均有腐生性细菌及弧菌生长,其中腐生性细菌主要存在于水母体现,而弧菌除存在于水母体表外,有的则能在水母体内深层生长,水母体细菌微生态研究结果表明,弧菌的占细菌总数的90％以上,通过改进TCBAS培养基,从水母体中分离得到6株优势类群的细菌,对其菌落特征、菌体形态、生理生化特性进行了研究,它们都具备弧菌属的共同特点：革兰氏阴性,氧化酶阳性,兼性厌氧,TCBS培养基上能生长,对O／129敏感,初步鉴定为弧菌属,研究还发现,这几株菌都能产蛋白酶,其中JF2、JF4、JF5、JF6产蛋白酶的能力明显较强,它们极有可能是导致水母捕捞后快速解体腐败的主要原因。     

Dopamine acts through a D2-like receptor on a jellyfish motor neuron

Summary Dopamine, which is present in nerve-rich tissues of the hydromedusa Polyorchis penicillatus, produces membrane hyperpolarization in identified motor neurons from this jellyfish. In this study we demonstrate that the inhibitory action of dopamine is mediated by conventional drug-receptor interactions which are reversible, saturable and specific. When 10 M dopamine was applied by micro-spritzing onto voltage-clamped (holding potential, –20 mV), cultured swimming motor neurons, an outward current of about 1 nA was evoked. Using this technique, we established a potency order for several amines: dopaminenorepinephrine>tyramine >octopamine>-phenylethylamine. Dopamine is effective at concentrations betweeen 1 × 10^-8 and 1 × 10^-3 M. Several dopamine receptor blockers such as fluphenazine, haloperidol and spiperone reduced the dopamine-induced current in a concentration-dependent manner. Although propranolol, a -adrenergic blocker, reduced the dopamine response and SKF 83566, a D₁ blocker, increased the response, it appears that the dopamine receptors in these jellyfish neurons share pharmacological properties with mammalian D₂ dopamine receptors.     

Increase in intracellular cAMP is a prerequisite signal for initiation of physiological oocyte meiotic maturation in the hydrozoan Cytaeis uchidae

In medusae of the hydrozoan Cytaeis uchidae, oocyte meiotic maturation and spawning occur as a consequence of dark-light transition. In this study, we investigated the mechanism underlying the initiation of meiotic maturation using in vitro (isolated oocytes from ovaries) and in vivo (ovarian oocytes in medusae) systems. Injection of cAMP derivatives into isolated oocytes induced meiotic maturation in a dose-dependent manner. Meiotic maturation was also achieved in isolated oocytes preloaded with caged cAMP and exposed to UV irradiation. The caged cAMP/UV irradiation-induced meiotic maturation was completely inhibited by blockers of protein kinase A (PKA), H-89, KT5720, and Rp-cAMPS. The medusae from which most parts of the umbrella were removed (umbrella-free medusae) survived for at least 2 weeks, during which time oocyte meiotic maturation and spawning occurred. When H-89 and Rp-cAMPS were injected into ovarian oocytes of umbrella-free medusae within 3 min of dark-light stimulation, meiotic maturation was inhibited or delayed. An increase in intracellular cAMP was confirmed by FlCRhR, a fluorescent cAMP indicator, in ovarian oocytes exposed to dark-light transition as well as in isolated oocytes stimulated by caged cAMP/UV irradiation. These results indicate that the cAMP/PKA signaling pathway positively contributes to light-triggered physiological oocyte meiotic maturation in Cytaeis uchidae.     

Structural analysis of O-glycans of mucin from jellyfish (Aurelia aurita) containing 2-aminoethylphosphonate

The structure of O-glycan in qniumucin (Q-mucin), which is a novel mucin extracted from jellyfish, was analyzed by a combination of NMR and ESI-MS/MS. A previously unidentified monosaccharide involved in the glycan chains was determined to be N-acetylgalactosamine (GalNAc) substituted by 2-aminoethylphosphonate (AEP) at the C-6. The O-glycans in Q-mucin from Aurelia aurita were proved to be mainly composed of three monosaccharides: GalNAc, AEP-(O→6)-GalNAc, and P-6-GalNAc. To the best of our knowledge, this is the first example of an O-glycan structure of glycoproteins containing AEP. This exceptionally simple structure of Q-mucin and its potential use in material science and technology are revealed.     

Vertical niche overlap by two ocean giants with similar diets: Ocean sunfish and leatherback turtles

We used satellite tags to record the patterns of depth utilisation for four ocean sunfish (Mola mola) and two leatherback turtles (Dermochelys coriacea) moving in broadly the same area off South Africa. Individuals were tracked for between 2 and 8 months and dive data relayed via satellite. For all the sunfish and one of the turtles, we received binned data on depth distribution, while for the second turtle we received individual dive profiles along with the proportion of time spent diving. Leatherback turtles dived almost exclusively within the upper 200 m, spending only 0.6 and 0.2% of their time > 200 m. There were times when sunfish likewise occupied these relatively shallow depths. However, there were also protracted periods when sunfish spent the majority of their time much deeper, with one individual remaining around 500 m for many hours at a time. These results suggest that sunfish sometimes exploit deeply distributed prey which is beyond the foraging range of leatherback turtles. We conclude that while both species are believed to feed predominantly on gelatinous zooplankton, the fact that sunfish do not need to come to the surface to breathe means that they can occupy an expanded vertical niche compared to the leatherback turtle.     

海蜇胶原蛋白肽的降血脂及抗氧化作用的研究

本研究以海蜇胶原蛋白为原料,经酶解得到海蜇胶原蛋白肽,探讨海蜇胶原蛋白肽对小鼠血脂的影响及抗氧化作用。以高脂饲料喂养ICR小鼠,建立高脂血症模型,研究胶原蛋白肽对小鼠肝系数和脂肪系数的变化情况及小鼠血脂水平、肝组织抗氧化功能的影响。结果表明海蜇胶原蛋白肽能显著降低小鼠肝系数和脂肪系数,能显著降低高脂血症小鼠血清总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、动脉硬化指数(LDL-C/HDL-C)水平,升高高密度脂蛋白胆固醇(HDL-C)和抗动脉粥样硬化因子(HDL-C/TC);能提高肝组织超氧化物歧化酶(SOD)谷胱甘肽过氧化物酶(GSH-Px)的活力,并能减低丙二醛(MDA)的含量。海蜇胶原蛋白肽具有辅助减低血脂水平和增强抗氧化功能的作用。     

闽江口海蜇渔业生态学研究

根据1993年5～9月的调查材料,研究了福建闽江口海域海蜇的渔业生态学。其密度和生物量高峰分别出现在6月20日和7月10日;群体伞径范围为18～546mm,平均328.8mm.体重范围为0.5～9540g,平均2877.4g;伞径为345～485mm的雌性有性繁殖力在1120.6×10⁴～3754.8×10⁴粒,平均2444.7×10⁴粒,有性生殖期在8月初至11月;采用高次方程和指数高次方程分别模拟伞径和体重生长,生长方程为:Φ_t=12.1337+17.7048t+3.1385t²-0.2049t³+0.00302t⁴,log_eW_t=-0.5749+1.4818t-0.0771t²+0.00129t³;以生物经济学原理确定7月20日为合理开捕期,开捕伞径为465.8mm.讨论分析了执行合理开捕期和开捕规格,对保护和合理利用海蜇资源,提高经济效益的重要意义.