鲍低氧胁迫响应机制的研究进展

鲍养殖业已成为我国海洋经济发展中的重要组成部分。近年来，因低氧胁迫，特别是高温低氧联合胁迫而导致的养殖鲍大规模死亡的现象时常发生，给鲍养殖业带来了严重的经济损失，已成为阻碍鲍养殖业健康可持续发展的重要环境因素。本文从鲍的生长、存活、生理生化指标 (包括心率、代谢、酶的活性、pH等)、免疫机能、胁迫响应基因及其表达调控等方面综述了鲍低氧胁迫响应机制的研究进展，以期为进一步研究鲍的低氧胁迫响应机制、开展鲍耐低氧新品种的选育等提供参考。此外，本文还提出了鲍低氧胁迫的预防调控措施，希望对养殖业者减少因夏季低氧胁迫诱发的养殖鲍大规模死亡而造成的损失有所帮助。     

低氧对甲壳动物的影响及其分子调控研究进展

氧是众多生物赖以生存的首要条件,动物处于低氧环境时,机体的生化反应和生理功能也会相应发生改变,严重时可引起一系列机体损伤甚至死亡。低氧胁迫下的应激机制是涉及多基因参与的复杂的生理调控过程,与哺乳动物相比,甲壳动物的低氧应激与分子适应机制尚不明晰。本文分析了低氧胁迫产生原因,并从生理层面阐述了甲壳动物对低氧胁迫的应激反应和生理适应策略、以及低氧对甲壳动物的行为、存活、抗氧化能力和代谢的影响,又从HIF-1信号通路、AMPK信号通路以及细胞凋亡通路阐述了甲壳动物对低氧环境胁迫的分子响应机制。本文在总结低氧信号传导及其调控通路研究进展的基础上,提出了低氧胁迫对甲壳动物影响的预防和调控手段,包括选育耐低氧新品种和营养调控手段,以期为人们更深入地理解甲壳动物低氧应激和分子适应机制提供理论参考。     

2种养殖模式对鲍营养成分与低温胁迫响应的差异比较

为研究不同养殖模式中的皱纹盘鲍(Haliotis discus hannai Ino)的营养成分与低温胁迫响应的差异,采用南北接力养殖鲍和北方底播养殖鲍作为研究对象,于2021年9月取样测量了肌肉组织中的总糖、蛋白质、有机物总量和氨基酸含量等营养成分和低温胁迫下的耗氧率和心率等生理指标。结果显示,底播养殖个体的总糖含量为(3.20±0.00)%、有机物总量为(27.60±3.70)%、必需氨基酸含量为(4.19±0.09)%,均显著高于南北接力养殖的个体(P<0.05)。低温胁迫条件下,南北接力养殖和底播养殖个体的耗氧率分别为(0.017±0.006)和(0.018±0.009) mg/(g·h),无显著差异(P>0.05);然而,底播养殖个体的心率为(12.82±1.72) BPM,显著低于接力养殖个体[(18.11±2.79) BPM] (P<0.05)。研究表明,不同养殖模式显著影响皱纹盘鲍养殖个体的营养价值及其响应低温胁迫的生理过程,底播养殖个体有着更高的营养价值和低温耐受能力。此外,心率可作为高敏感性的指标应用于研究鲍等贝类响应低温胁迫的生理机制。     

温度胁迫对皱纹盘鲍生理和生化活动的影响

为探讨温度胁迫下皱纹盘鲍(Haliotis discus hannai Ino)的响应机制,采用室内控温实验,通过设置4个温度梯度(5℃、10℃、20℃和25℃),设计温度骤变处理组(皱纹盘鲍从15℃暂养温度直接转移至各实验温度)和温度缓变处理组(0.5℃/12 h),分析温度剧烈变化和温度缓慢变化对皱纹盘鲍耗氧率和排氨率的影响及其差异性;并对高温和低温处理下皱纹盘鲍消化腺中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、酸性磷酸酶(ACP)和溶菌酶(LSZ)活性的变化情况以及不同组织(血细胞和肌肉组织)中Cu/Zn–SOD基因的表达状况进行了研究。结果表明,皱纹盘鲍耗氧率和排氨率随海水温度的升高而增加,20℃达到最高值;25℃骤变处理组与缓变处理组耗氧率和排氨率间存在极显著差异(P0.01)。5℃和10℃骤变处理组皱纹盘鲍氧氮比(O/N)同缓变处理组间存在极显著差异(P0.01)。在高温胁迫后的3 h,消化腺中SOD、CAT和LSZ活性达到最高,而ACP活性在胁迫6 h后达到最高(P0.01);低温胁迫显著降低皱纹盘鲍LSZ的活性,于胁迫9 h后达到最低(P0.01)。不同温度胁迫下,皱纹盘鲍血细胞和肌肉组织中Cu/Zn–SOD基因的相对表达量均表现上调,与对照组存在显著差异性(P0.05)。本研究表明,温度胁迫能显著影响皱纹盘鲍的生理和生化活动,这将有助于探讨皱纹盘鲍夏季高死亡率的原因,为皱纹盘鲍健康养殖提供一定的理论依据。     

温度胁迫对扇贝响应机制的研究进展

简述了温度胁迫对扇贝生理和抗氧化酶活性的影响。分析了温度胁迫对扇贝分子的影响机制,包括对扇贝热休克蛋白基因表达以及信号传导的响应途径。提出,由于扇贝在生长过程中与其逆境胁迫的复杂性,今后应运用多种环境因子的综合作用,对扇贝展开多重适应性的逆境研究,进而了解扇贝生理状态及分子响应机制;深入开展有关扇贝耐温性的全基因组的破译、GWAS分析以及关键基因挖掘与调控序列等分子方面的研究,进而从分子层面深入分析扇贝有关环境适应与生命演化的基本规律;进行优良品种的选育,使用基因工程等手段,降低温度对扇贝造成的影响。     

海藻糖对高温胁迫龙须菜的生理及基因表达的影响

摘要：大型海藻龙须菜（Gracilariopsis lemaneiformis）主要用来养鲍和提取琼胶,但其产量与栽培周期受夏季高温限制。海藻糖作为一种信号分子在对抗高温、干旱等逆境胁迫中发挥了重要作用。为了探讨海藻糖在大型藻类抗逆中的作用及其机制,本文研究了外源海藻糖对高温胁迫下龙须菜的生长、抗逆相关化合物和代谢酶、水杨酸及相关基因表达的影响。结果表明10 mmol/L海藻糖的添加促进了龙须菜的生长（相对生长速率为对照组的1.39倍）和部分叶绿素荧光参数的升高;促进了脯氨酸的积累（为对照组的1.34倍）,而丙二醛（MDA）含量和脂氧合酶（LOX）活性降低。同时,外源海藻糖激活了龙须菜中海藻糖-6-磷酸合成酶（TPS）和异分支酸合酶（ICS）的活性,显著促进了水杨酸的积累,其含量是对照组的2.05倍,此外,热激蛋白70（hsp70）基因、lox1和 ics基因在海藻糖添加后表达上调,而lox2基因在12 h表达下调。可见,海藻糖可以通过缓解高温对细胞膜的损伤、增强抗胁迫物质和水杨酸积累等来保护高温胁迫的龙须菜。     

海参养殖防控高温新举措

为解决海参养殖中夏季高温造成的水质恶化、海参爆发性死亡问题,提出了加深池塘、清淤、改良礁体、设置遮网、井水冷却等海参养殖池塘改造的技术要点,及降低密度、换水、调控底质等海参养殖中的技术管控措施,以保障海参顺利渡夏,降低养殖风险,提高养殖效益。     

长期饥饿胁迫下厚壳贻贝的生理生化响应及性腺转录组分析

为探究贻贝在饥饿胁迫下的生理生化响应及分子适应机制,本研究以二龄厚壳贻贝为对象,开展了正常投喂（对照组）和饥饿处理（饥饿组）条件下的存活率统计、能量代谢相关酶活测定以及性腺转录组测序及分析。结果显示,厚壳贻贝在90 d的饥饿处理下存活率高达86%;饥饿胁迫下贻贝性腺中磷酸烯醇式丙酮酸羧激酶（PEPCK）活性显著增加,己糖激酶（HK）、磷酸果糖激酶（PFK）、琥珀酸脱氢酶（SDH）、苹果酸脱氢酶（MDH）活性均显著降低（P<0.05）;通过Illumina Hiseq X10高通量测序平台对对照组和饥饿组厚壳贻贝性腺组织进行转录组测序,分别获得31 596 762和26 810 506个在其基因组上具有唯一注释的有效数据,并筛选出4 130个差异表达基因,包括2 082个上调和2 048个下调表达基因。GO功能分析结果显示差异基因主要在富集在代谢过程、细胞器组织以及酶活性等功能;KEGG富集分析结果表明,差异基因显著富集在DNA复制、错配修复、碱基切除修复等与细胞分裂有关的代谢通路上。本实验结果表明,贻贝在饥饿下通过降低细胞的能量代谢以及减缓细胞分裂等生理活动来维持饥饿胁迫下的生存。本研究初步揭示了厚壳贻贝在饥饿胁迫下的生理生化响应和分子调控机制,为今后深入解析贻贝应对饥饿胁迫的分子策略提供重要的理论依据,同时为揭示其适应饥饿胁迫的能量利用和再分配以及生理对策提供新的思路。     

夏季北黄海贝类养殖区环境因子、长牡蛎糖原和免疫指标变化的调查研究

为解析夏季环境胁迫和长牡蛎（Crassostrea gigas）机体响应特征,实验针对2021年北黄海夏季高温降雨期的长牡蛎养殖海区开展了2次调查研究和对比分析。结果显示,7月份海区表层水温分别为25.3 ℃和24.9 ℃,盐度分别为26.41和27.87;表层海水中硅藻丰度分别为3.6×103和3×103 个/L,低于往年平均水平,甲藻多样性增加,表层海水中细菌的总丰度分别为2.10×109和2.77×1010 拷贝/L,弧菌丰度分别为3.37×108和5.40×108 拷贝/L;长牡蛎肝胰腺糖原含量分别为40.96和31.58 mg/g、闭壳肌糖原含量分别为6.63和8.91 mg/g;鳃MDA含量分别为13.74和8.69 nmol/mg prot、鳃T-AOC分别为0.46和0.77 U/mg prot;海区养殖长牡蛎血淋巴细胞中CgIL17-5和CgTNF-1的mRNA表达量在第一次调查时相对室内暂养长牡蛎均剧烈升高;血淋巴细胞中CgCaspase3的mRNA表达量升高但差异不显著。综上,2021年北黄海贝类养殖区在经历6—7月夏季高温降雨期后出现水温升高和盐度降低现象,硅藻丰度较往年平均水平下降而甲藻多样性增加,细菌总丰度较入夏前水平降低而弧菌丰度显著升高。与室内暂养对照组长牡蛎相比,海区养殖长牡蛎的糖原含量下降,并发生轻度氧化应激。研究结果有助于我们进一步理解夏季养殖环境的变化规律和长牡蛎机体响应特征,为预防夏季大规模死亡发生提供理论依据和参考。     

“东优1号”杂色鲍苗种培育技术

杂色鲍(Haliotis diversicolor),又称九孔、九孔鲍,是我国南方重要的海水养殖品种.由于其成品规格较小(5cm～7cm),达到商品规格所需的养殖时间较其他鲍种短,再加上其风味独特,深受中国、台湾、日本等东亚地区人民的喜欢. 中国大陆的杂色鲍养殖产业开始于20世纪90年代初,但伴随着杂色鲍养殖产业的快速发展,大规模的流行性疾病不断发生.特别是2005年之后,在各杂色鲍主养区普遍流行的"养成期暴发性死亡症"给杂色鲍养殖企业造成巨大损失,养殖产量急剧下降.大量研究已表明,养殖杂色鲍种质的退化是导致暴发性病害流行的根本性原因.     

Molecular cloning,expression and functional analysis of a predicted HdiQM gene in small abalone,Haliotis diversicolor

The small abalone (Haliotis diversicolor) is a mollusc and was cultured in south of china. Problems such as the decreasing pathogen‐resistance and their mass mortality during the summer. The increased immunity of small abalone populations is a key factor in resolving these problems. Thus, the study of immunity‐related genes in small abalone has become important. In this study, three bacterial species were initially isolated from small abalone carcasses. The regression of infection was analysed, which revealed that the bacteria species could cause rapid morbidity in small abalone. A QM‐like gene (HdiQM) was found and bacterial challenge tests showed that HdiQM gene expression was induced by the bacterial isolates from small abalone carcasses. Therefore, our results implied that HdiQM was found to be an inflammatory stress‐inducible gene associated with pathogen infection, with important functions in small abalone immunity.     

Effect of proline‐enriched abalone feed on selected metabolite levels of slow‐growing adult Haliotis midae

Abalone is currently considered South Africa's most successfully produced aquaculture export product, with a 76% share of the total value generated by the aquaculture sector. A major risk factor for this sector is slow growth rates experienced during farming. Abalone feeds are often supplemented with amino acids in an attempt to enhance abalone growth. This is a first investigation of the effect of added proline to standard abalone feed, on the metabolite profile of slow‐growing abalone. A targeted liquid chromatography tandem mass spectrometry metabolomics research approach was followed to recognise the metabolic response of abalone showing slower growth performance. The addition of proline to the standard abalone diet was found to serve as a substrate for amino acid catabolism in slower growing abalone, by means of proline breakdown to assist with energy production via the tricarboxylic acid cycle. Other amino acids and urea cycle intermediates, that is, arginine, asparagine, ornithine and creatine further support energy production via the action of protein catabolism in slow‐growing abalone. Additionally, the importance of understanding how abalone respond metabolically to modified feed highlights the use of metabolomics to answer abalone aquaculture farming questions.     

Fluctuations in the heart rate of abalone in response to low salinity stress

The tremendous expansion of Chinese abalone production has not been without challenges such as low salinity stress, which may occur during severe summer rainstorms and typhoon events. Interspecific hybrids have, however, been of great use to the aquaculture industry in withstanding environmental stresses. This study adopted the non-invasive method of measuring heart rate to monitor the cardiac performance of the Pacific abalone and two of its interspecific hybrids during the incidence of continuous salinity decrease. The results showed that low salinity significantly influences the heart rate of abalone. Fluctuation in the abalone’s heartbeat suggests a pattern with three phases and two breakpoints of salinity (BOS1 and BOS2). BOS1 represents an isosmotic point, and BOS2 represents lethal salinity. We argue that relatively lower BOS suggests better tolerance to low salinity, and long-term exposure to salinities around BOS2 could be detrimental to all three species. The hybrid H. discus hannai ♀ x H. fulgens ♂ (DF) recorded the lowest BOS1 and BOS2, which was also significantly different (P?=?0.01) from DD at BOS1, suggesting a better tolerance potential for low salinities than the other species. Altogether, our data establish species-specific BOS and reveal the cardiac mechanism by which abalone responds to low salinity. The results confirm that the non-invasive heart rate detection method could likewise be adopted to define critical salinities for abalone, and hybridization could be a potential method to breed the more stress-resilient aquatic animals.

     

斑节对虾MKK7基因的克隆及在不同胁迫条件下的表达分析

丝裂原活化蛋白激酶激酶7（MKK7）是JNK（c-Jun N-terminal kinase）信号通路的关键调控因子,参与调节细胞对各种胞外刺激的反应。本研究利用RACE技术克隆获得了斑节对虾（）,其全长为2710 bp,包括14 bp的5''非编码区（UTR）、1295 bp的3''UTR和1401 bp的开放阅读框（open reading frame,ORF）,编码466个氨基酸。多重序列比对和系统进化树分析结果表明,基因聚为一支并且具有最高的同源性（99.14%）。定量表达结果表明,Staphylococcus aureus）组和鳗弧菌（Vibrio harveyi）组,这两种组织中的表达量均显著低于对照组。两组低盐（17、3）胁迫后,肝胰腺和鳃组织中的PmJNK在各组的表达均受到抑制,表明MAPK信号转导通路可能在斑节对虾免疫防御和盐度应激过程中发挥重要作用。     

一种生态化鲍育苗和养成模式的构建

该研究目的是建立一套鲍育苗和养殖的生态化模式,包括鲍苗种生态培育模式、鲍陆基生态养成模式和海上鲍藻套养生态养成模式,以克服目前鲍养殖业存在的病害频发、成活率低下等问题,提高鲍养殖的经济效益,降低养殖风险。鲍苗种生态培育模式通过＂光照-微藻-微生态制剂-滤食性动物-鲍苗＂构建复合生物体系;鲍陆基生态养成模式通过池内建立＂复合生物区系＂,并在池外设立生态塘和生态渠进行养殖废水处理的方式构建;海上生态养成模式通过＂鲍藻套养＂构建。共培育鲍苗5批次,培育周期210～240d,共产出鲍苗17.764×104个,平均壳长1.5cm以上,育成率0.78%～1.23%。陆基生态化模式养成商品鲍43.774×104个,平均壳长6.53cm,平均体质量34.6g,成活率87.5%,周期18～20个月。海上鲍生态养成150口网箱,养成商品鲍3×108个,平均壳长6.50cm以上,成活率85%以上,养成时间18～20个月。     

Culture methods of live algal feeds for European aquaculture: optimising culture conditions for Ulvella lens

The Japanese development of mass culture techniques for Ulvella lens during the 1980s for aquaculture has stimulated the development of rearing techniques for abalone and sea urchins in producing countries. However, since the late 1980s, there has not been any in-depth evaluation of culture methods for U. lens, nor the development of a new robust method for aquaculture operators. The use of this known inducer for settlement of veliger larvae has not been employed on a commercial scale in Ireland or in European aquaculture systems. The new methodology described here has produced a threefold increase in the settlement of sea urchins (Paracentrotus lividus) and is recommended for adoption by the European aquaculture industry.     

软体动物疱疹病毒及其对贝类养殖产业的危害

中国是贝类养殖大国,30余年来,贝类养殖产量总体稳中有升,但部分贝类的养殖产业因疫病影响出现严重萎缩、甚至消失。20世纪90年代以来,中国多种双壳贝类和杂色鲍(Haliotis diversicolor supertexta)因感染疱疹病毒出现大规模死亡,成为近年来危害中国贝类养殖业的主要病原。经流行病学调查和病原鉴定,引起中国双壳贝类和杂色鲍死亡的疱疹病毒分别为牡蛎疱疹病毒(Ostreid herpesvirus 1,OsHV-1)和鲍疱疹病毒(Haliotid herpesvirus 1,HaHV-1)。贝类疱疹病毒病不仅在中国发生,同时也在全球多个国家、地区传播和暴发,引起全球贝类养殖从业者和科研人员的广泛关注。多国学者从病毒特征、流行病学、诊断技术、生态防控和抗病育种等多个角度展开研究,以期减轻此类病毒对贝类产业造成的危害。大量科研力量的投入使OsHV-1和HaHV-1成为分类地位明确,研究最深入、最全面的贝类病毒性病原。本文对近年来OsHV-1和HaHV-1研究领域取得的主要成果进行总结,重点介绍其在中国和全球范围的发生、传播过程、产业危害和防控措施等。     

Food chain dynamics of abalone in a polyculture system

The food chain dynamics of three species of commercially important abalone — the red abalone (Haliotis rufescens), the green (H. fulgens) and the Japanese (H. discus) — were measured to determine their relative success in the multispecies aquaculture system at Woods Hole Oceanographic Institution. The abalone were fed sea lettuce (Ulva lactuca) used in the polyculture system to remove nutrients regenerated by the bivalves.This polyculture system was operated on a moderate-sized scale during the summer of 1973. Growth and feeding rates of the abalone were measured during a 112-day period and net growth efficiency was calculated (net production/food ingested). All three species grew during the experiment but H. rufescens had the lowest efficiency of 10.2%, and H. fulgens had the highest efficiency of 22.7%. These differences might be due to the temperature regime (16–23°C) during the experiment. H. rufescens is typically found in colder waters whereas H. fulgens is common in warmer Southern California waters. The results suggest the feasibility of the browsing role of abalone in polyculture systems.     

Self-thinning dynamics in experimental scallop populations

Self-thinning-related mortality has been encountered in extensively cultured scallop populations. Here we report an experiment aimed at studying actual population dynamics of scallops undergoing self-thinning and develop a model of the process. Scallops were kept in small tanks at various initial population densities. Growth and survival were monitored for 39 months. Two cohorts were monitored (cohorts 1 and 2 were 1 and 2 years old, respectively). Growth was density-dependent in cohort 2. Survivorship was high in cohort 1 during the first summer but mass mortality occurred during the second summer. Mortality in cohort 2 peaked during the first summer. In both cohorts, peak mortality occurred at age 2+ years and thus was uncoupled among cohorts. Therefore, negative environmental factors are ruled out as explanations of mortality. Instead, it appears as if self-thinning interacted with some ontogenetic factor. Although cohort 1 was undergoing self-thinning, trends in biomass–density curves were non-monotonous because of mass mortality. In contrast, self-thinning in cohort 2 followed a classical pattern. One possible mechanism for such contrasting differences was that 1+-year-old scallops produced byssal threads and attached to one another during the first year, forming multilayered clumps. This behaviour disappeared during the second year and mass mortality was experienced as scallops adopted a single-layered arrangement. Although details may differ among species, the process depicted above provides a potential trigger to the sequence of events leading to mass mortality in scallop culture. Our model suggests that self-thinning occurred in all density groups, with a common slope but with different elevations in the biomass–density space.