Biochemical responses of the striped mullet Mugil cephalus to oil exposure I. Acute responses—Interrenal activations and secondary stress responses

Acute single exposures to the water-soluble fraction (WSF) of a No. 2 fuel oil influences several biochemical parameters in juveniles of Mugil cephalus Linnaeus. Plasma cortisol and glucose concentrations were measured at 1 and 3 h after exposure to 1, 5, 10 or 20% WSF. No elevation of plasma cortisol or glucose levels occurred in fish exposed to the lowest concentration of oil, whereas a dose-response relationship was observed at higher doses. The dynamics of plasma corticosteroid, glucose and cholesterol concentrations and osmolality as well as accumulation of naphthalenes in the fish tissues were monitored during exposure to 20% WSF. Circulating cortisol concentrations rose rapidly to 5 times normal values 1h after exposure to oil and subsequently declined to control levels 6 h after oil addition. A smaller secondary rise occurred at 12 h, but cortisol had returned to basal levels 12 h later. In contrast, plasma glucose, cholesterol and osmolality rose more slowly to reach maximum values between 3 and 4 h after oil addition. By 24 h plasma cholesterol and osmolality had returned to normal values whereas the hyperglycemia persisted. However, 72 h after the addition of WSF all biochemical parameters had returned to control levels. At this time considerable accumulation of total naphthalenes had occurred in several fish tissues, whilst the concentration of total naphthalenes in the exposure tanks had declined to background levels. When freshly prepared 20% WSF was added to the exposure tanks during this period, all biochemical parameters were again elevated. The results suggest that the volatile components of fuel oil in the water trigger the biochemical changes described in a dosedependent manner. The possible ecological significance of these changes and the potential use of these parameters as sublethal indicators of environmental contamination are discussed.     

Sardine (Sardina pilchardus) stress reactions to purse seine fishing

Observations from the purse seine fishery off northern Portugal are used to describe the early dynamics of sardine (Sardina pilchardus) stress reactions and identify likely stressors during the commercial fishing operation. Sardine blood and muscle were sampled from the onset of fishing (school identification and encircling) to the end of fish transfer onboard (90–120 min later). The evolution of haematocrit, haemoglobin, cortisol, glucose, ionic concentrations, ATP and its catabolites were modelled using linear mixed models as a function of time spent in the net, biological (sex, reproductive state and condition) and operational variables (catch, light level and phase of fishing operation). Significant linear trends with time were detected for most stress variables and mean concentrations after 2 h in the net were similar to literature values corresponding to acute stress reactions for teleosts. Biological variables were rarely significant and explained a small proportion of variation, while operational variables were never significant. For each stress variable, levels varied considerably between trips but the temporal evolution was common across trips. Random trip effects were uncorrelated among most biochemical variables, suggesting that distinct factors affected each stress variable during the sampled trips. However, the linear trend with time spent in the net observed for most stress variables indicates that the duration of the fishing operation is an important stressor in purse seine fishing due to the progressive water volume restriction, crowding and manipulation associated to the fishing method.     

运输应激对二花脸和皮特兰猪血浆应激和代谢相关激素水平的影响

比较二花脸和皮特兰猪在2h运输过程中血浆ACTH、皮质醇、胰岛素和T3、T4水平的动态变化模式,以分析内分泌激素变化的品种特征.选用雄性二花脸猪10头,皮特兰猪6头,体重达20kg时安装颈静脉瘘管,1wk后运输试验,运输过程中不同时间点采集血样,放射免疫分析法测定血浆激素水平.上车后两品种猪ACTH水平缓慢上升,60min后达到峰值,下车后15min恢复至基础水平,运输过程中ACTH水平及变化幅度均未表现显著的品种差异;运输前皮质醇水平二花脸显著高于皮特兰猪,上车后两品种皮质醇均迅速上升,出发后15min达到峰值,下车后15min均快速恢复至基础水平,运输过程中皮特兰皮质醇上升的幅度显著高于二花脸猪;两品种胰岛素水平上车后均呈下降趋势,二花脸胰岛素水平总体上显著高于皮特兰猪;T3水平在上车后也表现快速下降,无论是T3水平还是其变化幅度均不表现显著的品种差异;皮特兰猪上车后T4水平稍微下降而二花脸猪显著下降,皮特兰T4水平总体显著高于二花脸猪.运输应激伴随血浆ACTH和皮质醇水平升高,而胰岛素、T3和T4水平下降,皮质醇水平升高的幅度能够反映猪的应激敏感性.图1参25     

Endocrine stress response in Oreochromis sp. from exposure to waterborne cadmium: the plasma cortisol analysis

Cadmium (Cd) is known as one of the most dangerous environmental and industrial pollutants. It has no biological function and accumulates mainly in metabolically active tissue even at low concentrations, which in turn may cause tissue damage. The effect of Cd on the endocrine systems of fish is not well known. To test the hypothesis that Cd is a chemical stressor, Oreochromis sp. were exposed to waterborne cadmium chloride and their endocrine stress response (plasma cortisol) was investigated after 4 days and 20 days. The plasma cortisol levels were analyzed using reverse-phase high performance liquid chromatography with UV detection (λ = 250 nm) after liquid–liquid extraction. The detection limit of the method was found to be 0.87 ng/mL plasma. This study provides evidence that Cd probably causes exhaustion of endocrine systems. Oreochromis sp. exposure to Cd resulted in a 15%–53% and 52%–91% suppression of cortisol release after 4 days and 20 days of exposure, respectively, in comparison with the control group. The results suggest that Cd still activates the endocrine system at 20 days and the interrenal cells of Oreochromis sp. were not impaired after 20 days of exposure to Cd.     

Influence of electromagentic field exposure on serum glucose and cortisol levels in Guinea pigs

Studies showed significant disturbances of electromagnetic fields on metabolism of carbohydrate, lipid, proteins, as well as enzyme activities. In this investigation, the effect of whole-body magnetic field (MF) on glucose and cortisol levels was studied on 30 adult male Guinea pigs. Guinea pigs were exposed to sinusoidal 5 Hz, 0.015 µT and 50 Hz, 0.21 µT MF for 2 and 4 h per day over a 7-day period. Blood samples were taken, and serum glucose was measured by an auto analyzer, and cortisol by radioimmunoassay. The results showed significant decreased serum glucose and cortisol levels in 50 Hz, 0.21 µT MF after 2 or 4 h exposure. A greater decrease was noted in exposure after 2 or 4 h with 50 Hz, 0.21 μT compared to 5 Hz, 0.015 μT MF in all samples. The results indicated a direct relation between MF exposure, serum glucose, and cortisol levels.     

Ni2+胁迫对铜绿微囊藻（Microcystis aeruginosa）和集胞藻（Synechocystis sp.）的生长和光合色素的影响(Effects of Nickel on Growth and Photosynthetic Pigments of Microcystis aeruginosa and Synechocystis sp.)

光合作用是蓝藻生长繁殖的生理基础,研究重金属胁迫下蓝藻光合色素的变化和响应,有助于揭示其受害机理.在实验室无菌纯培养条件下,研究了不同浓度Ni2+处理下铜绿微囊藻和集胞藻的生物量和光合色素随时间的变化趋势.结果表明:浓度为5mg·L-1～25mg·L-1的Ni2+对M.aerugonisa的生长有抑制作用,随着处理剂量的增加和处理时间的延长,抑制作用愈加显著;在短时间(24h)内,Ni2+对Synechocystissp.的生长没有显著影响,随胁迫时间延长呈现出抑制作用;Ni2+处理M.aerugonisa至24h及Synechocystis sp.至48h时,藻细胞光吸收能力整体上受到明显抑制;5mg·L-1～25mg·L-1的Ni2+胁迫下,M.aerugonisa和Synechocystis sp.的叶绿素a含量随胁迫时间延长而降低;在叶绿素a(Chla)、藻蓝蛋白(PC)和别藻蓝蛋白(APC)三种光合色素中,藻蓝蛋白(PC)对Ni2+胁迫最为敏感,是Ni2+伤害蓝藻的重要作用位点.Ni2+对M.aerugonisa的抑制作用比Synechocystis sp.更明显.     

高锰酸钾对中国花鲈的毒性效应

为给中国花鲈(Lateolabrax rnaculatus)养殖的病害防治提供理论数据,研究了高锰酸钾对中国花鲈鱼苗和幼鱼急性毒性,检测了暴露于不同质量浓度高锰酸钾中,幼鱼肝脏的谷胱甘肽(GSH)和丙二醛(MDA)含量以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷丙转氨酶(GPT)和谷草转氨酶(GOT)活力.结...     

Between-individual variation in haemocyanin concentrations in the Norway lobster<Emphasis Type="Italic"> Nephrops norvegicus</Emphasis> following exposure to hypoxia and manganese

Environmental hypoxia and the release of reduced manganese (Mn) are often combined stress factors in marine sediments. Previous investigations have shown that hypoxia induces variable responses in the concentration of the respiratory pigment haemocyanin (Hc) of crustaceans. A recent study demonstrated that the magnitude and direction of the changes was dependent on the initial level of Hc in individuals of the Norway lobster Nephrops norvegicus. The changes also took place within 24 h rather than days as suggested by previous studies. In this present study we investigated changes of Hc in individual N. norvegicus in uncontaminated sea water after exposure to and release from realistic hypoxic stress (PO ₂=6.0 kPa). Furthermore we investigated how concomitant exposure to realistic concentrations of manganese (20 mg l ^-1) modified the responses we observed. We confirmed a between-individual variation in response and a change in Hc towards an optimum level after hypoxia, but also showed that changes that took place post-hypoxic exposure occurred over a timescale similar to that of the hypoxic response itself. Manganese exposure resulted in no significant changes in Hc whereas Mn exposure combined with hypoxia resulted in a significant decrease (15%) in all individuals independent of initial Hc. N. norvegicus was thus unable to compensate for the effects of hypoxia by synthesis of Hc after exposure to naturally occurring Mn concentrations.     

Individual differences in foraging behavior and cortisol levels in recently emerged brook charr (Salvelinus fontinalis)

Recently emerged brook charr (Salvelinus fontinalis) foraging in still-water pools along the sides of streams tend to be either sedentary, feeding from the lower portion of the water column (a sit-and-wait tactic), or very active, feeding from the upper portion of the water column (an active search tactic). We tested whether the individual differences in foraging behavior were associated with baseline concentrations and responses of cortisol, a steroid hormone linked to personality differences in a variety of animals including fishes. We quantified the proportion of time spent on moving by focal charr in the field and then capturing them. Captured individuals were either (i) sacrificed immediately to quantify baseline cortisol concentrations, (ii) held in an unfamiliar field environment for 15 min and then sacrificed to quantify cortisol concentrations in response to handling and holding in a novel field environment, or (iii) held in an unfamiliar field environment with a white Plexiglas base (stressor) for 15 min to quantify cortisol concentrations in response to a novel object. Eleven statistical models relating cortisol concentrations to the proportion of time individuals spent on moving while searching for prey were compared using multi-model inferencing. Cortisol concentrations were higher for charr that spent a lower proportion of time on moving in the field than for charr that spent a higher proportion of time on moving. For a given proportion of time spent on moving, mean cortisol concentrations between baseline and experimental treatments, our measure of cortisol response, did not differ markedly. Our findings suggest that the foraging tactics displayed by wild brook charr in the field could reflect differences in how individuals perceive their environment.     

Biochemical responses during starvation and subsequent recovery in postlarval Pacific white shrimp,Penaeus vannamei

Postlarval shrimp, Penaeus vannamei Boone, 1931, were held individually in cages and exposed to two feeding regimes. One group was starved for 12 d and then fed during the following 12 d. A second group was fed throughout the 24 d study. Four individuals were sampled from each of the two groups on Days 0, 1, 2, 4, 8, 12, 13, 14, 16, 20, and 24. Molting and growth among the starved-fed postlarvae stopped after 2 d starvation, while fed postlarvae increased significantly in size throughout the 24 d study. Among the starved-fed postlarvae, water content increased rapidly in response to starvation. DNA and sterol concentrations increased significantly during starvation due to selective catabolism of cellular components. After 12 d, RNA concentration was not significantly different between the fed and starved-fed postlarvae, but became significantly higher in the starved-fed postlarvae 48 h after feeding resumed. Triacylglycerol reserves were severely depleted during the first day of starvation, while protein concentrations began to decrease after the second day of starvation. RNA, protein, and the polyamines spermidine and spermine, when expressed as a ratio to DNA, decreased in response to starvation. Concentrations of all measured parameters in the starved-fed postlarvae returned to levels similar to those in the fed group 8 to 12 d after feeding resumed. Results of this study suggest that triacylglycerol provides energy during short periods of starvation, while protein is utilized during prolonged starvation. The ratios of RNA:DNA, protein:DNA, spermidine:DNA, spermine:DNA, two unidentified amine compounds, and percent water content are all useful indicators of prolonged nutritional stress in postlarval P. vannamei.     

Response of embryos of the sea urchin Strongylocentrotus purpuratus to aqueous petroleum waste includes the expression of a high molecular weight glycoprotein

The present study investigated the sublethal effects of the largest aqueous waste associated with offshore oil development, produced water (PW), on sea urchin embryo development. PW inhibited normal gastrulation in purple sea urchin (Strongylocentrotus purpuratus) embryos exposed at the hatching stage. The exposed embryos did not form complete archenterons, and secondary mesenchyme cells exhibited an unusual behavior with respect to the wall of the blastocoelic cavity. In addition, an abundance of extracellular matrix was observed in the blastocoelic cavities in the embryos exposed to higher concentrations of PW. An inhibition of the development of embryos through the pluteus stage was observed as a result of PW exposure. This was manifested by inhibition of normal spicule formation with concomitant abnormal pluteus morphology. To determine if a biochemical stress response occurs as a result of PW exposure, embryos at the early gastrula stage were exposed to PW for 2 h, followed by an additional 1 h in 3H-leucine and PW. These embryos expressed a 253 kDa protein as observed by one-dimensional SDS (sodium dodecyl sulfate) polyacrylamide gel electrophoresis and autoradiography. This protein could occasionally be observed in gels stained for protein, and was glycosylated as demonstrated by staining with periodic acid Schiff (PAS). The 70 to 73 kDa heat-shock proteins previously described in sea urchin embryos (and other organisms) as a result of stress were not synthesized as a result of PW exposure. Heat shock did not induce synthesis of the 253 kDa glycoprotein. Combined PW and heat-shock exposure elicited both the heat-shock response (73 kDa protein) as well as expression of the 253 kDa glycoprotein. These data demonstrate the use of expression of endogenous macromolecular markers to distinguish exposures of embryos to different perturbations. Arsenic (as sodium arsenite), a metal constituent of PW, also induced the 253 kDa glycoprotein in early gastrula-stage embryos. We suggest that this glycoprotein may be a marker for PW (and a metal constituent) exposure in sea urchin embryos, and may be related to morphological abnormalities.     

Intraspecific variation in the red alga Portieria hornemannii : monoterpene concentrations are not influenced by nitrogen or phosphorus enrichment

The red alga Portieria hornemannii (Lyngbye) Silva was selected to test the effects of enhanced nutrient availability on the production of carbon-based secondary metabolites, because of its notable site-to-site variation in monoterpene production. On Guam, the major secondary metabolite produced by this alga is ochtodene, a cyclic monoterpene. Quantitative high-performance liquid-chromatography analysis of the extracts of P. hornemannii collected from six sites on Guam showed that both ochtodene and triglyceride concentrations differed significantly among sites. Internal nitrogen and phosphorus content of the algae did not correlate with the observed variation in chemistry. Experimental enhancement of N-alone, P-alone or N + P in the field for 5 wk failed to induce a significant change in ochtodene concentrations in the alga, while triglyceride concentrations increased significantly in the N + P treatment. Ochtodene and triglyceride concentrations did not change among similar treatments in shaded (18 d) and unshaded (11 d) fertilization experiments conducted in the laboratory. Variation in ochtodene concentrations in P. hornemannii cannot be attributed to N and P availability; however, the decrease in ochtodene and triglyceride concentrations during the shaded laboratory experiment suggests that light may be a factor influencing monoterpene biosynthesis. The difference in ochtodene concentration between the initial and final sets of field controls collected for the unshaded laboratory experiment suggests that temporal variation might also contribute to differences observed among the algae at the different sites. Received 11 June 1996 / Accepted 20 July 1996     

Metabolic responses of the prawns Palaemon elegans and P. serratus (Crustacea: Decapoda) to acute hypoxia and anoxia

Using prawns, Palaemon elegans (Rathke) from intertidal pools on the Isle of Cumbrae, Scotland, and P. serratus (Pennant) from the subtidal at Plymouth, England, some metabolic responses to hypoxia and anoxia have been studied. P. elegans was found to have a greater tolerance of severe hypoxia than P. serratus. Tolerance of totally anoxic conditions, however, was limited to only 4 h in P. elegans and to approximately 1 h in P. serratus. exposure to moderate hypoxia (30 torr) resulted in little change in the concentration of L-lactate in the blood or in the tissues of either P. elegans or P. serratus. When exposed to extreme hypoxia (10 or 5 torr for P. elegans), however, there was a progressive increase in the concentration of L-lactate in the blood and in the tissues of both species. After normoxic conditions had been restored, the concentration of L-lactate in the blood and in the tissues returned to normal resting levels more rapidly in P. elegans than in P. serratus. Under hypoxic conditions, both P. elegans and P. serratus showed an increase in the concentration of blood glucose and a slight reduction in the glycogen content of the tissues. The concentrations of blood glucose and of tissue glycogen returned to normal levels within 6 h of the prawns being returned to normoxic conditions. The results of an in situ study in April and August 1986 to examine the metabolic responses of P. elegans to the hypoxic conditions normally experienced in high-shore rock pools are also presented. The ecological significance of the differing abilities of these species to survive hypoxic exposure is discussed.     

水环境中重金属铜暴露下青鳉鱼的行为响应

采用生物行为传感器监测青鳉鱼在重金属铜暴露下的行为数据,分析不同暴露浓度(20、10、5、1和0.1 TU)下青鳉鱼的行为响应。20、10、5、1和0.1 TU的暴露浓度下青鳉鱼对重金属污染的行为反应模式符合环境胁迫阈值模型,且不同浓度梯度重金属对青鳉鱼产生不同的行为毒性效应。利用重金属作用下青鳉鱼的行为变化来研究重金属环境胁迫导致的生物行为响应机制,从而得到重金属暴露下生物行为的实时变化过程和趋势,可对水环境生态系统质量进行综合评价。     

水环境中重金属铜暴露下青鳉鱼的行为响应

本研究采用生物行为传感器监测青鳉鱼重金属铜暴露下的行为数据,分析不同暴露浓度(20、10、5、1和0.1 TU)下青鳉鱼的行为响应。20、10、5、1和0.1 TU的暴露浓度下青鳉鱼对重金属污染的行为反应模式符合环境胁迫阈值模型,且不同浓度梯度重金属对青鳉鱼产生不同的行为毒性效应。通过本研究,利用重金属作用下青鳉鱼的行为变化来研究重金属环境胁迫导致的生物行为响应机制,从而得到重金属暴露下生物行为的实时变化过程和趋势,可对水环境生态系统质量进行综合评价。     

氯化镉和敌敌畏突发胁迫下斑马鱼的行为差异

采用计算机摄像跟踪技术,以正常水体中斑马鱼的行为变化为基础,比较突发性氯化镉和敌敌畏污染胁迫下斑马鱼的个体行为(游动速度、深度、转弯次数和加速度)和鱼群行为(平均距离和分散度)的变化规律.研究结果表明:斑马鱼在两种污染物突发性胁迫下,行为反应快速且敏感,游动行为响应与污染物种类和暴露时间直接相关;两种不同类型的污染胁迫...     

Facilitation across stress gradients: the importance of local adaptation

While there is some information on genetic variation in response to competition in plants, we know nothing about intraspecific variation in facilitation. Previous studies suggest that facilitation should increase fitness in stressful environments. However, whether a plant experiences an environment as stressful may depend on prior adaptive responses to stressors at a site. Local adaptation to stress at a site may reduce the likelihood of facilitation. Seeds of Plantago erecta from stressful (serpentine soil) and non-stressful (non-serpentine soil) edaphic environments were reciprocally planted into these two soil types. Although competition did not differ significantly among seed sources, there was evidence for a local adaptation effect on facilitation. Non-serpentine seeds planted into serpentine soil exhibited greater individual plant biomass at higher densities. The interaction between population source and growth environment indicates a role for evolutionary processes such as local adaptation in the expression of facilitation in plants.     

三苯基锡对大鼠肥胖发生的影响

三苯基锡(triphenyltin,TPT)和三丁基锡(tributyltin,TBT)在环境中经常同时存在,针对TBT对肥胖发生的影响已有较多研究,但TPT能否诱导肥胖的发生尚不明晰.本研究用环境水平的TPT(0.5、5和50 μg·kg-1)对青春期Sprague Dawley大鼠进行灌胃处理54 d后,测量大鼠体...     

Aversive and avoidance responses of female mice to the odors of males infected with an ectoparasite and the effects of prior familiarity

The detection and avoidance of parasitized males is a component of female mate choice. Here we show that female mice can distinguish between the odors of individual males infected with an ectoparasite, the murine louse, Polyplax serrata, and uninfected males. Female mice displayed aversive responses to, and avoided the odors of, parasitized males. A 15 min exposure to the urinary odors of infected males induced an endogenous opioid-peptide-mediated reduction in pain sensitivity or analgesia, while a brief 1 min exposure to the odors elicited a non-opioid-mediated analgesic response. These neuromodulatory mechanisms facilitate the expression of a variety of anxiety and stress associated responses of which pain inhibition is one component. Females further distinguished between novel and familiar infected males. Prior exposure to the odors of an infected males reduced the degree of analgesia expressed and the associated levels of anxiety and stress and their concomitant costs. In a Y-maze odor preference test females also displayed a marked overall preference for, and initial choice of, the odors of clean, uninfected males and an active discrimination against, and avoidance of, the odors of both familiar and novel infected males. These findings indicate that female mice can distinguish between males infected with an ectoparasite and clean uninfected males and display aversive and avoidance responses to infected males. They also show that females can discriminate between individual infected males and modulate their aversive responses to the odors of infected males on the basis of prior familiarity. This is likely part of the mechanisms whereby females can both reduce the transmission of ectoparasites, such as lice, to themselves and select for parasite-free males.