应激颗粒的形成与生物学意义

真核细胞对外界压力刺激会做出一系列应答反应,如暂停蛋白质翻译系统,从而使细胞能更好地适应环境压力。通过应激颗粒（stress granules,SG）的形成包裹未被翻译的mRNA是该适应性调节的重要方式。研究表明,环境压力导致eIF2α上游激酶的激活从而磷酸化eIF2α,翻译起始受阻,随后,TIA-1、TTP等蛋白迅速与mRNP结合聚集成SG,并在微管蛋白的帮助下进一步向细胞核聚集,形成成熟的SG。当压力消失,SG依赖微管及其动力蛋白进行解聚,释放包裹的mRNA及蛋白。细胞内成熟的SG在转录后调节中发挥重要作用,并且通过其组成蛋白在肿瘤凋亡、病毒侵染、免疫、炎症反应及由蛋白错误折叠引起的疾病中发挥作用。该文首次综述了压力颗粒研究进展,为充分认识SG的病理生理性调节功能提供参考。     

鱼类耳石微结构特征的研究与应用

鱼类耳石的结构与组成相当稳定,可能反映鱼类的生长情况及一生所经历的环境变化.自20世纪70年代以来,耳石微结构研究领域迅速发展,成为研究鱼类早期生活史的基础.耳石微结构的检测与分析(Otolith microstructure examination and analysis)已成为当今鱼类生态学及渔业生物学研究中的一项重要而公认的技术1,为准确研究鱼类的种群生态学特征提供了新途径,不仅具有一定的理论意义,而且有较广泛的应用前景.       

应激对水生动物生长、行为和生理活动的影响

简要介绍了应激对水生动物生长,行为和生理活动影响的研究进展,阐明了应激对动物的生长,行为,体液免疫,细胞免疫以及内分泌功能都有明显地抑制作用,提供水生动物对多种应激源反应的信息,有助于全面了解这方面的研究动态。     

鱼类对海洋升温与酸化的响应

自工业革命以来,空气中人为排放CO₂量增加,引起温室效应,导致地球表面温度升高和海水升温;同时,由于海-气界面气体交换,大气中CO₂部分溶解于海洋,引起海洋酸化。海洋升温加快鱼体内生化反应和代谢速率,并通过影响生长、觅食和繁殖等生命过程中能量供给,间接影响到鱼类种群分布、群落结构及生态系统的功能。而海水酸化会干扰海洋鱼类仔稚鱼的感觉和行为,增加其被捕食率,并削弱其野外生存能力,可能威胁自然种群补给量。综述了海洋升温、海洋酸化及其两者共同作用对海洋鱼类的影响,为预测鱼类响应全球海洋环境变化的响应趋势提供相关依据。     

手术应激与免疫抑制

手术前后时期的心理应激和生理应激均可抑制细胞免疫功能,主要表现为T淋巴细胞和自然杀伤（natural killer,NK）细胞的数量减少和活性减弱。手术创伤越大,对免疫的抑制作用越强,因而对手术后的痊愈有明显影响。一般而言,手术应激所致的免疫抑制可以恢复,恢复的时间主要取决干手术创伤的大小。目前认为,手术引起免疫抑制的机制主要与下丘脑-垂体-肾上腺皮质轴、交感神经系统、细胞因子、阿片肽和T细胞信号分子有关。选用某些不具有免疫抑制作用的止痛药物,以及蛋白酶抑制剂,可以防治手术应激所致的免疫抑制作用。     

鱼类的护幼行为

就体外和体内护幼行为,介绍10种鱼类的护幼生态现象.     

长江三峡库区鱼类资源现状的研究

1997－2000年在长江三峡库区的巴南和万州江段共监测1292船次,统计 渔获物4096．38kg,生物学测定2464尾,共采集鱼类30种,分属8科24属,目前库区渔获物组成和结构与20世纪70年代相比发生了较大变化,白甲鱼,中华倒刺靶,岩原鲤等在渔获物中比较已经很少,铜鱼资源也明显下降,Gua,Gan,鳊等在渔获物中已基本消失,而南方鲇,鲤,黄颡鱼等比较相对上升,渔获物中高龄鱼个体减少,低龄鱼及幼鱼个体比重增加,与70年代资料相比,三峡库区鱼区资源已呈衰退趋势。     

运输过程中水质和鱼类生理指标的变化及运输控制策略

鱼类运输应激是世界范围内面临的重要问题, 标准化运输操作规程的制定有利于水产养殖业的健康发展。血浆皮质醇是经典的应激评价指标, 在运输过程中持续上升, 适用于鱼类短途和长途运输, 而血糖则更适用于鱼类短途运输。乳酸、CO₂、渗透压等生理指标也应更多的被应用于运输应激评价。水质恶化(尤其是pH降低和氨累积)和应激反应是鱼类运输中急需解决的关键问题, 而现有的解决措施并不完善。水质和生理指标是相互影响的, 相关研究中应联合分析两者对运输的影响。文章综合分析了运输对鱼类造成的应激反应、水质恶化以及常用的抗应激运输措施, 进而对后续研究进行展望, 旨在为相关的研究提供基础资料。     

微卫星DNA标记及其在鱼类遗传多样性研究中的应用

微卫星DNA作为第二代分子遗传标记是高等真核生物基因组中种类多、分布广、具有高度的多态性和杂合度的分子标记,由于其具有多态性检出率高、信息含量大、共显性标记、实验操作简单、结果稳定可靠等优点,已经成为种群遗传学研究中被广泛应用的分子遗传标记。微卫星DNA标记技术在鱼类的群体遗传结构的分析、物种遗传多样性的鉴定以及遗传基因连锁图谱的构建等方面已初步得到应用。该文就微卫星技术的原理方法,在鱼类遗传多样性研究中的应用概况以及应用范围和注意事项等方面进行综述。为微卫星技术在鱼类遗传多样性研究中应用提供了理论参考。     

环境DNA技术在鱼类生态学中的应用研究进展

全球渔业衰退是21世纪人类面临的重要挑战之一。为了有效地遏制鱼类资源的衰退,精确的鱼类生态调查是其首要任务。传统的鱼类监测以渔获物采集与形态学鉴定为主,往往耗时耗力且效果不佳,已无法满足现阶段大尺度上的精确调查。环境DNA （eDNA）技术作为一种近年来新兴的鱼类生态调查方法,其与传统方法相比具有灵敏度高、经济高效、采样受限小且对生态系统无干扰的优势,目前其已被广泛地应用于鱼类物种监测、多样性调查、生物量评估以及繁殖活动监测等方面的研究。然而,eDNA技术在鱼类生态学研究的具体应用中暴露出的一些问题将会影响其监测结果的精确性,诸如操作流程的不规范、基因数据库的不完善以及eDNA在环境中生态学过程的不明确等。鉴于上述原因,首先对eDNA技术的发展历程、分析流程以及eDNA技术在鱼类生态学研究领域中的研究进展进行了综述,而后着重分析了eDNA技术的发展当前所面临的困难与挑战,并提出了相应的解决方案,最后对eDNA技术未来在鱼类生态学研究领域中的发展趋势做出了展望。通过本研究,以期能够为eDNA技术在鱼类生态学领域中的准确应用提供理论基础。     

转基因鱼的研究进展与商业化前景

转基因技术为鱼类育种开辟了新的途径。目前已培育出转生长激素基因鲤、鲑和罗非鱼,转荧光蛋白基因斑马鱼与唐鱼等可稳定遗传的转基因鱼品系,其中快长转生长激素基因鱼的获得对于提高水产养殖的产量与养殖效益具有十分重要的意义。文章简要综述了转基因鱼应用研究的成就、相关技术及生态安全方面的研究进展。显微注射仍是目前基因转植的常用方法,应用转座酶或巨核酸酶介导的转基因新技术可提高基因转植效率与整合率。转基因元件的选择应尽量考虑"全鱼"基因或"自源"基因,以减少转基因鱼食用安全方面的顾虑同时也有利于转植基因的表达与生理功效的发挥。生态安全是转基因鱼商用化面临的最大问题。虽然有研究显示转基因鱼与传统的选育鱼类相比适合度较差,但由于环境与基因型间的相互作用,根据实验室获得的转基因鱼对生态影响的结果,难以预测转基因鱼一旦逃逸会对自然水生态环境产生怎样的影响。因此应建立高度自然化的环境以获得可靠的数据客观评价生态风险,有效的物理拦截、不育化处理等生物学控制策略仍是保证转基因鱼安全应用的关键措施。     

Salivary cortisol assessment for stress detection in the Asian elephant (Elephas maximus): A pilot study

Effects of introducing an unfamiliar female into an Asian elephant herd at Tierpark Berlin were monitored by means of salivary cortisol assessment. Saliva samples were obtained from a second female for comparative purposes. The period of familiarization was characterized by an enhanced cortisol level in both animals, with a maximum on the second day after joining. Cortisol returned to normal on the following day. Manipulations of the keepers caused a transitory increase on two other days. Possibilities for the use of this noninvasive method of stress monitoring in various management situations are indicated. © 1992 Wiley-Liss Inc.     

Sound the alarm: A meta‐analysis on the effect of aquatic noise on fish behavior and physiology

The aquatic environment is increasingly bombarded by a wide variety of noise pollutants whose range and intensity are increasing with each passing decade. Yet, little is known about how aquatic noise affects marine communities. To determine the implications that changes to the soundscape may have on fishes, a meta‐analysis was conducted focusing on the ramifications of noise on fish behavior and physiology. Our meta‐analysis identified 42 studies that produced 2,354 data points, which in turn indicated that anthropogenic noise negatively affects fish behavior and physiology. The most predominate responses occurred within foraging ability, predation risk, and reproductive success. Additionally, anthropogenic noise was shown to increase the hearing thresholds and cortisol levels of numerous species while tones, biological, and environmental noise were most likely to affect complex movements and swimming abilities. These findings suggest that the majority of fish species are sensitive to changes in the aquatic soundscape, and depending on the noise source, species responses may have extreme and negative fitness consequences. As such, this global synthesis should serve as a warning of the potentially dire consequences facing marine ecosystems if alterations to aquatic soundscapes continue on their current trajectory.     

The biology of triploid fish

This review deals with major areas of triploidy research in fish. It includes not only methods for induction and detection of triploidy but also the impact of triploidy on morphology, anatomy, growth, haematology, energetics, behaviour, endocrinology and gonads in various species of fish, studied so far. The future prospects of research on triploid fish are discussed inviting researchers with diverse areas of interest in fish biology.     

A comparison of health assessment approaches for evaluating the effects of contaminant-related stress on fish populations

Various methods are available for investigating the effects of environmental conditions or stress on fish ranging from assessments at the individual level to the population and community level. Each method, however, has limitations and advantages, and the type of method used influences the interpretation of stressor effects on fish health. We compared and evaluated three methods for investigating the effects of contaminants on fish health for populations in a stream receiving a variety of industrial effluents including PCBs, heavy metals (primarily mercury), and chlorine. These methods are: (1) individual bioindicator variables including measurements of biochemical, physiological, histopathological, and organismal-level responses, (2) statistically based integrative indices based on multivariate responses, and (3) integrative ecologically relevant measurements such as population and community-level responses. Many of the individual-level measurements reflect biochemical and physiological conditions and are therefore short-term response indicators of stress. Use of several individual variables in multivariate discriminant analysis allows a more integrative approach for evaluating response of fish to stressors. Community- and population-level measurements integrate the responses to a variety of environmental conditions and therefore may be less reflective of contaminant-induced stress. The three methods used together provide the best strategy for evaluating fish health in order that environmentally sound decisions can be made regarding the implications of contaminant-related stress on aquatic ecosystems.Managed by Martin Marietta Energy Systems, Inc., under contract DE-AC05-840R21400 with the U.S. Department of Energy.     

Osmoregulation and muscle water control of the Amazon fish Oscar Astronotus ocellatus (Cichlidae) when facing salinity stress

Specimens of Oscar Astronotus ocellatus from a fish farm were abruptly submitted to salt stress of 14 ppt and 20 ppt, for 3 and 8 h to determine their plasma osmolality. Muscle wet body mass change in vitro was analyzed from control freshwater animals. Fish in 14 ppt presented no osmolality distress even after 8 h. In 20 ppt, a slight increase (10%) in plasma osmolality was observed for both times of exposure when compared to control fish. Muscle slices submitted in vitro to hyper-osmotic saline displayed decreased body mass after 75 min, and slices submitted to hypo-osmotic saline displayed increased body mass after 45 min when compared to control (isosmotic saline). These results reinforce A. ocellatus’s euryhalinity. The fish were able to regulate its internal medium and tolerate 14 ppt, but presented an intense osmotic challenge and low muscle hydration control when facing salinities of 20 ppt.     

Behavioral coping strategies in a cichlid fish: the role of social status and acute stress response in direct and displaced aggression

The African cichlid fish, Astatotilapia burtoni, has a complex social system with a sophisticated social hierarchy that offers unique opportunities to understand how social rank and its physiological substrates relate to behavioral strategies. In A. burtoni, a small fraction of the males are dominant (T, territorial), as distinguished by being large, brightly colored, reproductively active, and aggressively defending territories. In contrast, the majority of males are non-dominant (NT, non-territorial), being smaller, drably colored, sexually immature, and typically schooling with females. The social system is regulated by aggressive interactions between males and behavioral responses to aggression can be direct or displaced with respect to the animal that acts. To determine whether direct and displaced behaviors are differentially exhibited by T and NT males, individuals were shown a video presentation of a dominant male displaying aggressively. Analysis of aggressive acts toward the video display and displaced activity toward a tank mate revealed that T males exhibited more direct behavior (toward the video display), while NT males engaged in more displaced behavior (toward tank mates). Because similar experiments with primates suggest that shifts in behavioral strategies are linked to changes in the stress response (as measured by circulating cortisol levels), we measured cortisol levels of T and NT males following exposure to the aggressive stimulus. Although in some animals subordinate males are reported to have higher cortisol levels, here we show that in A. burtoni the endocrine response to specific situations can vary considerably even among animals of the same status. Interestingly, NT males with intermediate cortisol levels showed more directed behavior while NT males with both high and low cortisol levels showed more displaced. This suggests an optimal physiological stress response in NT males that predisposes them to challenge aggressors perhaps making it more likely for them to ascend in status.