氰氟虫腙干扰斑马鱼(Danio rerio)鱼鳔的发育

氰氟虫腙(metaflumizone)是一种钠离子通道阻断类杀虫剂,目前已被广泛应用于作物保护和病虫害防治。已有研究报道氰氟虫腙对水生生物的发育具有一定的影响,然而关于氰氟虫腙对水生生物尤其是鱼类发育的毒性效应和潜在的分子机制仍知之甚少。在本研究中,斑马鱼胚胎暴露于0.1、1和10μmol·L^-1氰氟虫腙,记录了氰氟虫腙暴露后斑马鱼胚胎的存活率、孵化率和畸形率,并通过病理学切片染色分析了幼鱼鱼鳔的形态变化,同时采用胚胎整体原位杂交技术比较了氰氟虫腙处理组和对照组之间鱼鳔发育关键基因的转录水平变化情况。结果表明,氰氟虫腙处理后会引起斑马鱼胚胎孵化延迟和幼鱼鱼鳔充气障碍,同时在氰氟虫腙处理后鱼鳔发育的关键基因(pbx1a、hprt1l和elovl1a)的表达水平显著降低。这些结果表明氰氟虫腙能明显抑制斑马鱼鱼鳔的发育,暗示鱼鳔可能是氰氟虫腙毒性作用的潜在靶器官,这些结果将为氰氟虫腙的生态风险评估提供参考信息。     

污染物对鱼类的甲状腺激素干扰效应及其作用机制

环境中可以影响生物体甲状腺激素合成、运输、作用和代谢等过程的化学污染物称为甲状腺激素干扰物(TDCs),TDCs被认为是继环境雌激素之后最重要的一类内分泌干扰物.鱼类甲状腺的结构、甲状腺激素的转运和功能等与哺乳动物有较大差别.与哺乳动物相比,污染物干扰鱼类甲状腺激素的研究还较为缺乏.在介绍鱼类甲状腺结构、功能以及甲状腺激素在鱼体内动态过程的基础上,分析了污染物对鱼类的甲状腺激素干扰效应及其作用机制,探讨了今后鱼类甲状腺激素干扰研究的主要方向.污染物能对鱼类甲状腺激素水平、相关酶活性及甲状腺结构等产生直接影响;同时,污染物还可以通过干扰鱼类甲状腺系统对由甲状腺激素调节的重要生理过程如生长、繁殖和发育等产生间接影响.污染物主要通过干扰鱼类甲状腺激素的合成与分泌、转运、清除以及与甲状腺激素受体(TR)的相互作用等机制对鱼类产生不利影响.在污染物对鱼类甲状腺激素干扰的研究中,今后应重点关注环境中"新型"卤化有机污染物、鱼类早期发育过程与甲状腺激素干扰效应的关系、TR介导机制以及TDCs的筛选方法等.     

环境污染物造成鱼类视觉缺陷的研究进展

多溴联苯醚、重金属、双酚类化合物和农药等环境污染物在多种环境介质中广泛被检出,众多研究表明视觉缺陷的发生也与环境污染物的广泛存在密切相关.视觉系统的正常发育和视觉功能的形成对鱼类摄食、集群和繁殖等生命活动具有重要作用,而视觉缺陷将会影响其生存和种群稳定,因此环境污染物所产生的视觉缺陷备受研究者关注.本文以鱼类的眼睛发育...     

环境污染物干扰鱼类体色的研究及其生态毒理学意义

鱼类体色对环境污染物十分敏感,使其成为污染监测中理想的生物指示物,具有广阔的应用前景.鱼类体色调控复杂,涉及的基因丰富.本文综述污染物对鱼类体色的干扰作用及可能的干扰机制,为鱼类体色应用于污染监测相关生物标志物筛选及生态风险评估提供参考资料;同时,从鱼类色素合成和代谢、色素细胞发育和迁移、体色变化的调控等方面,综述鱼类...     

氯化石蜡急性暴露对斑马鱼胚胎发育的毒性效应

比较研究了8种商品化氯化石蜡(CPs)急性暴露对斑马鱼(Danio rerio)胚胎早期发育的影响.实验结果表明,浓度分别为1、5、10和20 mg.L-1的CPs暴露7 d后均不会造成斑马鱼胚胎死亡,对斑马鱼胚胎的孵化率也无明显影响,但部分商品化CPs暴露对斑马鱼幼鱼鱼鳔发育具有明显的致畸效应,且随着暴露浓度的升高,鱼鳔畸形率显著上升,存在着明显的剂量-效应关系;此外,4种未氯化的短链石蜡烃(C10—C13)暴露对斑马鱼胚胎发育没有明显的毒性.上述研究结果表明,CPs急性暴露可造成斑马鱼幼鱼鱼鳔发育畸形,而这种致畸效应与CPs的含氯量不相关,与CPs中未经氯化的短链石蜡烃也无相关性,CPs对鱼类胚胎早期发育的潜在毒性效应需要进一步关注.     

金属污染物对神经系统损害及毒性机制研究进展

神经系统与生物体其他系统联系密切,共同维持机体正常的结构和功能。环境中的金属污染物可通过多种途径进入生物体,干扰幼年或成年动物神经系统的发育和功能,其损害机制是目前研究的热点。本文系统地总结了汞、铅和铝等金属污染物对神经系统的损害作用,着重在细胞、分子和基因水平上阐述了金属对神经系统的毒性机制,在此基础上分析了当前研究的不足之处和发展趋势,并对今后的研究方向进行了展望。     

环境内分泌干扰物对鱼类性别分化的影响

鱼类性别分化是在性别决定机制的控制下,鱼类未分化的性腺向卵巢或精巢发育,并出现第2性征的过程,受自身内分泌系统的精确调控。环境内分泌干扰物能通过干扰内源激素的合成、释放、转运、代谢、结合和作用等过程影响鱼类的内分泌机能,从而对鱼类的性别分化产生影响。介绍了鱼类性别分化的模式和过程以及内分泌系统对鱼类性别分化的调控作用,综述了环境内分泌干扰物对鱼类性别比例、配子发生、性腺发育和第2性征的影响,从性类固醇激素的合成以及性别分化相关基因的表达两个方面探讨了环境内分泌干扰物影响鱼类性别分化的作用机制,并展望了该领域未来的研究方向。     

转基因作物对鱼类的生态毒理效应研究综述

转基因作物潜在的健康和环境风险一直以来颇受争议,转基因作物加工成动物饲料后可能会诱导动物产生免疫应激反应,影响动物的生长发育、繁殖等。鱼类是水生脊椎动物的代表,已广泛应用于水环境的监测,但目前转基因作物对鱼类的饲用安全性研究还相对较少。文章基于转基因作物作为鱼饲料原料对鱼类生态毒理学效应的研究现状,综述了转基因作物对鱼的生长表现、生理生化、脏器功能及发育、组织病理以及行为活动等方面的生态毒理学效应,分析了当前研究中存在的问题,并对今后的研究趋势进行了探讨。     

转基因作物对鱼类的生态毒理效应研究综述

转基因作物潜在的健康和环境风险一直以来颇受争议,转基因作物加工成动物饲料后可能会诱导动物产生免疫应激反应,影响动物的生长发育、繁殖等。鱼类是水生脊椎动物的代表,已广泛应用于水环境的监测,但目前转基因作物对鱼类的饲用安全性研究还相对较少。文章基于转基因作物作为鱼饲料原料对鱼类生态毒理学效应的研究现状,综述了转基因作物对鱼的生长表现、生理生化、脏器功能及发育、组织病理以及行为活动等方面的生态毒理学效应,分析了当前研究中存在的问题,并对今后的研究趋势进行了探讨。     

实时在线质谱在室内化学中的应用

室内空气化学组分复杂,包括各类氧化剂、挥发性有机物（volatile organic compounds,VOCs）等污染物.这些污染物会在空气中或室内表面发生均相和非均相反应生成危害性更大的二次有机污染物.检测室内空气中未被发现的新有机污染物并揭示其室内形成机制,不仅有助于更准确地评估室内空气质量,也有利于室内空气污染物的精准控制.本文总结了室内空气化学近十年的重要进展,并重点介绍了室内化学研究中3种代表性的实时在线质谱分析技术,这些实时在线质谱分析技术的应用极大促进了对室内污染物及其化学过程的理解,对评估室内空气暴露风险、精准防控室内空气污染、改善我国室内空气质量,具有重大意义.     

Effect of size and sex on buoyancy in the oyster toadfish

In 1991 we examined the developmental consequences of swimbladder growth and sexual dimorphism on specific gravity (SG) and percent buoyancy (%B) in the oyster toadfish (Opsanus tau Linnaeus collected in the York River, Virginia) and tested the hypothesis that large ovaries compensate for the buoyancy conferred by a smaller swimbladder in females. Weight in water (Ww) increased as a linear function of weight in air (Wa) for both sexes, and there were no sexual differences between regressions. SG and %B did not change with Wa, indicating proportional growth of body and swimbladder. SG averaged 1.049±0.002 and %B 3.183±0.160. Removal of the gonads had no significant effect on Ww, SG or %B, indicating that the larger ovaries did not compensate for buoyancy associated with a smaller swimbladder. In fact testis and ovary SG did not differ significantly from values for intact fish. However, gonad composition changed with development: testis SG and % fat decreased with gonosomatic index, whereas overy SG and % fat increased, but % water decreased. Removal of the swimbladder significantly increased SG to 1.083 and %B to 6. Swimbladder volume increased linearly with Wa and was significantly larger in males; adjusted means were 11.40±0.83 and 8.94±0.83 ml for males and females, respectively. Variability in bladder volumes contributed to the absence of sexual differences in SG and may be permissible because negative buoyancy imparts minimal selective advantage for precise volume and buoyancy control. The absence of a relationship between fish buoyancy and sexual dimorphism in bladder size supports evidence that sexual dimorphism in the swim-bladder relates to its function in sound production.     

Biological factors affecting the swimbladder volume of sardine (Sardina pilchardus)

Variations in the absolute and relative swimbladder volume of sardine (Sardina pilchardus W.), were examined in relation to fish length, gonads and stomach volume, and lipid content. Fifty specimens were frozen in liquid nitrogen and sliced with a cryo-microtome. From the slices, volume estimates of the organs were obtained through computer reconstruction. Variations in absolute and relative swimbladder volume in relation to fish length and the aforementioned organs' volume and lipid contents were estimated by means of multiple regression analysis. The relative importance of these variables in the calculations of the swimbladder volume for different physiological conditions of the fish was also assessed. The results revealed that the volume can be estimated from two distinct models: the first for the reproductive and the second for the non-reproductive period. The non-reproductive period model is in agreement with the well-known positive correlation of target strength with fish log length. However, during the reproductive period the relative size of gonads and relative lipid content gradually become more important than length.     

Role of wax esters in determining buoyancy inHoplostethus atlanticus (Beryciformes: Trachichthyidae)

Specimens of the orange roughyHoplostethus atlanticus were caught at the edge of the Chatham Rise, east of the South Island of New Zealand, in June 1988, during a commercial fishing voyage. Several tissues of the fish were found to contain large quantities of lipid almost entirely as wax esters. These tissues include a fat-invested swimbladder, the skin, skull and spine, and a fat-infiltrated tissue found in the neurocranial cavity. The physical properties of the wax esters have been examined relative to the temperatures that exist where the fish are found. Differential scanning calorimetry and NMR spectroscopy both suggest that at 6°C, the temperature at which the fish are located in the water column, the lipid is partially solid. However, at 14°C, the temperature at the surface where the fish are positively buoyant, the lipid is completely liquid. It is proposed that the increased density of the lipid at 6°C would make the fish neutrally buoyant in its normal habitat. The location of the lipidrich tissues has been examined relative to their possible buoyancy contribution, and a histological examination of the swimbladder has been performed.     

An experimental and theoretical analysis of the effect of added weight on the energetics and hydrostatic function of the swimbladder of European sea bass (Dicentrarchus labrax)

We conducted experiments to determine the effect of the increasing ultrasonic/radio transmitter weight on the routine metabolic rate of sea bass. We measured the oxygen consumption (MO₂) of fish tagged externally with a dummy transmitter made of a hollow pipe, the weight of which was adjusted with lead to represent in water 0, 1 and 4% (R_tf) of the animal weight. We then developed a theoretical model to estimate, for a given fish size, the range of added weight that fish can compensate for through swimbladder regulation. When R_tfБ%, MO₂ of untagged and tagged fish did not differ significantly. However, when R_tf reached 4%, fish that carried a tag incurred a significant elevation of oxygen consumption, which represented 28% of their total useable power (or metabolic scope). This result strongly supports the view that a high R_tf ratio contributes to a decrease in available metabolic energy by diverting energy from, e.g., growth or swimming performance. A comparison between the tagged fish and the theoretical model reinforced the hypothesis that, when R_tf attained 4%, the increase in metabolic rate reflected a supplementary and costly swimming effort necessary to maintain vertical position. In this condition, the swimbladder cannot regulate the buoyancy of tagged fish.     

The permeability to oxygen of the swimbladder of the mesopelagic fish Ceratoscopelus maderensis

The permeability to oxygen of the swimbladder of physoclistous fish is important because of the usually high oxygen content of the bladder. The oxygen permeability and guanine content of the swimbladder wall of the mesopelagic myctophid Ceratoscopelus maderensis (Lowe) were measured. The oxygen permeability was 0.0672 cm³ m/atm min cm² and the guanine content was 73 g/cm². Attention is drawn to the high rates of gas loss which would occur from a swimbladder with these characteristics and the problems of maintaining the gas content, especially at depth.     

Occurrence of inflated swimbladders in five species of lanternfishes (family Myctophidae) from waters off southern California

The swimbladders of three species of myctophid fishes (Symbolophorus californiensis, Tarletonbeania crenularis and Diaphus theta, collected in the Southern California Bight between 1963 and 1978), previously observed to have both inflated and noninflated swimbladders as adults, were examined to determine if the swimbladders either vary in their inflation on a diel basis or cease to be inflated and possibly become nonfunctional in some individuals. The swimbladders of two lanternfishes reported to lack inflated swimbladders as adults (Lampanyctus regalis and L. ritteri) were included in the study for comparison. Only the swimbladder of L. regalis did not increase in size with increasing fish size. In the remaining four species, both the lengths and volumes of noninflated swimbladders were positively correlated with fish standard length (SL). Although the swimbladder continued to increase in size, inflated swimbladders were not found in L. ritteri>2 mm SL. Inflated and noninflated swimbladders occurred in overlapping size ranges of S. californiensis, T. crenularis, and D. theta. Only 11% of the D. theta swimbladders were inflated, and the occurrence of inflated swimbladders dit not differ significantly with day vs night capture or fish size. Although the frequency of occurrence of inflated swimbladders decreased significantly in larger S. californiensis, both S. californiensis and T. crenularis caught at the surface at night with a neuston net had significantly higher proportions of inflated swimbladders than did those collected below the surface with either daytime or night-time trawls. The swimbladder does not appear to become nonfunctional in either species. Rather than maintaining either constant volumes or constant masses of gas in their swimbladders during their vertical migrations, both species may inflate their swimbladders only while in the surface waters at night, and have noninflated swimbladders while at other depths of their vertical ranges.     

Buoyancy function of the enlarged fluid-filled cranium in the deep-sea ophidiid fish Acanthonus armatus

Acanthonus armatus Günther (family Ophidiidae) is a slightly negatively buoyant (mean weight in surface seawater =0.58% of air weight) benthopelagic fish without a swimbladder that has reduced tissues and components (muscle, bone, brain, gills, lipids) and a massive head. This species has an enlarged cranial cavity (10% of head volume) filled, except for the very small brain, with a low-density (specific gravity 1.008) fluid. The fluid provided static lift of about 0.30 g each for 4 specimens whose weights in water ranged from 1.0 to 2.6 g. Osmotic concentrations of the cranial fluid averaged 294 mOsm 1^-1 in 4 specimens and , in 2 specimens for which comparisons were possible, were 43 to 45% lower than the concentrations of the plasma and perivisceral fluid. Similarly, Na⁺ and K⁺ concentrations of the cranial fluid were lower than those of the plasma or perivisceral fluid. A. armatus has highly reduced heavy tissues and an increased content of dilute fluid, with a localization of even more highly dilute fluid in the enlarged cranium which partially offsets the relatively dense tissues of the head. Information on the morphology, behavior and ecology of the fish supports the interpretation of the buoyancy and chemical data. The conclusion is consistent with the hypothesis that obtaining and conserving energy and reducing predation are the important selective factors affecting the evolution of deep-sea fishes and that these factors have greatly influenced the chemical composition of the fishes.     

环境内分泌干扰物对鱼类性别决定的影响研究进展

水体中的环境内分泌干扰物能够影响鱼类性别决定过程,对鱼类产生明显的雌、雄性化效应.为深入研究环境内分泌干扰物对鱼类性别决定的影响及其机制,论文介绍了鱼类性别决定基因SRY和DMY基因在鱼类性别决定中的作用,以及Sox、DMRT、CYP和Vasa、Dax1、Foxl2等鱼类性别决定相关基因对鱼类性别决定的调控作用,综述了各类环境内分泌干扰物引起的鱼类雌、雄性化效应的最新研究进展,在此基础上探讨了环境内分泌干扰物影响鱼类性别决定的作用机制,并展望了该领域今后的重点研究方向.     

有机污染物对发光菌和鱼的毒性相关性研究

研究有机污染物对不同水生生物毒性的种间关系有助于探讨有机污染物对水生生物的毒性作用模式。本文应用1 470种有机化合物对发光菌的毒性数据和949种有机化合物对鱼的毒性数据,研究有机化合物对发光菌和鱼的种间毒性作用模式。结果表明,有机化合物对发光菌和鱼的毒性呈正相关,但种间相关性较差。通过计算毒性比率TR值表明多数类别有机化合物具有相似的种间毒性作用模式。基线和弱惰性化合物对发光菌和鱼的毒性均与辛醇水分配系数log Kow具有良好的线性关系,这说明基线和弱惰性化合物在发光菌和鱼体内的残余量CBR值均为一个常数。这些化合物对发光菌和鱼具有相似的毒性作用模式和生物吸收过程。另外,一些亲水性化合物的log TR值具有较大的种间差异,即对发光菌和鱼的毒性效应具有较大的种间差异,表明亲水性化合物对发光菌为反应型化合物,而对鱼为麻醉型化合物。有机化合物对发光菌和鱼的毒性种间相关性通过引入疏水性参数得到了一定的改善,这表明这些亲水性化合物毒性效应的种间差异有一部分归因于有机化合物在发光菌和鱼体内的生物富集不同,而不是由于与生物分子的反应性不同。这些亲水性化合物相对于鱼的腮和皮肤更容易通过发光菌的细胞膜,与生物分子发生化学反应,从而具有较高的毒性效应。Log Kow大于7的化合物对发光菌和鱼均具有较低的毒性,说明有机化合物在生物体内的富集能力对有机化合物剩余毒性的判别起着重要作用。