Exploratory behaviour of goldfish Carassius auratus

The exploratory locomotor behaviour of twenty-one naïve goldfish in a homogeneous open field during 20-hr periods was monitored and analysed into spatial and temporal characteristics. The fish did not randomly explore the entire field. Locomotion is organized spatially and temporally. The fish moves about in one specific area during a specific time after which it displaces the centre of its activity to another area. The time spent in earch area is a function of rate of activity, expressed by a linear equation and, during the initial 4 hr, the elapsed time in the novel environment (novelty content). The area-by-area exploration was never replaced by random exploration throughout the environment during the 20-hr periods of observation.     

Calcium oscillations in the olfactory nonsensory cells of the goldfish, Carassius auratus

Background

The olfactory nonsensory cells contribute to the maintenance of normal functions of the olfactory epithelium (OE). Specifically, the ciliated nonsensory cells of teleosts play important roles in the odorant detection by OE in aqueous environment. Their cilia show strong beating activities and cause water flow at the OE surface, making the detection of odorants by OE more efficient. Because intracellular Ca²⁺ level has been reported to play an important role in ciliary beating, the ciliary beating activity may be regulated by intracellular Ca²⁺ dynamics of these ciliated nonsensory cells.

Methods

We performed Ca²⁺ imaging experiments to analyze the Ca²⁺ dynamics in acutely dissociated OE cells of the goldfish. Furthermore, we examined the contribution of the Ca²⁺ dynamics to the ciliary beating frequency (CBF) at the surface of the intact OE.

Results

Olfactory nonsensory cells showed both spontaneous intracellular Ca²⁺ oscillations and propagating intercellular Ca²⁺ waves. Application of 2-aminoethoxydiphenylborate (2-APB), which antagonizes IP₃-induced Ca²⁺ release from intracellular stores suppressed these Ca²⁺ oscillations. Furthermore, 2-APB application to the intact OE lamellae resulted in the decrease of CBF at the surface of the OE.

Conclusions

These results indicate that spontaneous intracellular calcium oscillations persistently up-regulate the ciliary beating at the surface of the OE in teleosts.

General significance

Ciliary beating activity at the surface of OE can be regulated by the Ca²⁺ dynamics of olfactory nonsensory cells. Because this ciliary movement causes inflow of external fluid into the nostril, this regulation is suggested to influence the efficiency of odorant detection by OE.     

Non-random oscillatory changes in orientation of the goldfish (Carassius auratus), in an open field

An analysis of orientation of seventy-four fish over 31 months, under controlled conditions of temperature, light, water quality, and flow, reveals systematic trends in the orientation of the goldfish population. Moreover, most fish exhibit one or more type of strong short term (hourly) oscillation. It may be concluded that the observed orientation is the resultant of a complex summation of many oscillatory forces.     

Phylogenetic origins of immune recognition: Lymphoid heterogeneity and the hapten/carrier effect in the goldfish, Carassius auratus

These studies were designed to determine whether the cellular response of the goldfish, Carassius auratus, to heterologous erythrocytes is comparable in complexity and shares similar recognition mechanisms with those of mammals. Immunocytoadherence has been used to monitor the anti-horse erythrocyte (HRBC) response. The levels and kinetics of antigen-binding activity in the thymus, head nephros, and spleen were established following a single high (25%) or low (0.0025%) HRBC challenge. Rabbit anti-goldfish IgM was found to inhibit antigen binding of thymocytes, as well as other immunocytes. Hapten-carrier immunization was used to explore lymphoid heterogeneity in this species. The anti-hapten (2, 4, 6-trinitrophenyl) response was found to be specifically enhanced by carrier priming. The helper function of carrier-stimulated cells was short lived and greatest when low-dose carrier priming was used. The proportion of low-dose, carrier-stimulated thymus and head nephros antigen-binding cells was substantially enriched by passage through a nylon-wool column. However, previously carrier-primed and hapten-stimulated secretory antigen-binding cells were depleted by comparable column separation. The results of hapten-carrier immunization in combination with column separation are indicative of lymphoid heterogeneity for this species. They suggest that cell-cell collaboration is a general and essential part of the vertebrate immune response. Antigen-specific recognition of both lymphoid subsets seems likely to be mediated by surface immunoglobulin, since anti-IgM inhibits antigen binding of thymus and head nephros immunocytes.     

Leptins and leptin receptor expression in the goldfish (Carassius auratus). Regulation by food intake and fasting/overfeeding conditions

Leptin is a hormone involved in feeding and body weight regulation in vertebrates, but the relationship between energy status and leptin has not been clearly established in fish. The aim of this study was to investigate in a teleost, the goldfish (Carassius auratus), the tissue expression pattern of two leptins (gLep-aI and gLep-aII) and leptin receptor (gLepR); and the effect of feeding on expression of these genes. Leptin system expression in goldfish was firstly analyzed in fish under overfeeding (2 weeks) or fasting (1 week), and secondly, at different postfeeding times (0, 3, 6, 9 and 12 h). Goldfish has two Lep-a paralog genes, gLep-aI was widely expressed in central and peripheral tissues, whereas gLep-aII was preferentially expressed in brain. This different distribution pattern of leptins suggests that they can play different physiological roles in goldfish. The gLepR mRNA was ubiquitous expressed, with the highest expression in the telencephalon and hypothalamus. No significant differences in the leptin system expression were found among control, overfed and fasting groups, suggesting an apparent lack of correlation between nutritional status and leptin system in goldfish. Hepatic expression of gLep-aI significantly increased 9 h after feeding time, while hypothalamic leptin system expression did not change after feeding. In summary, leptin in goldfish could signal short-term changes in food intake, as postprandial satiety, but seems to be independent of fasting/overfeeding conditions in this teleost. The widespread distribution of leptins and leptin receptor in goldfish strongly supports that this hormone may have pleitropic actions in fish.     

Argulus japonicus: Sperm transfer by means of a spermatophore on Carassius auratus (L)

The process of sperm transfer is somewhat enigmatic in Argulus, even though copulation has been witnessed. A breeding colony of Argulus japonicus was kept under laboratory conditions in order to study reproduction in the species. Pairs in copula were removed and studied with histology and scanning electron microscopy to describe the mechanism of sperm transfer. Sections of copulating pairs revealed sperm on the accessory copulatory structures of the male’s swimming legs; and scanning electron microscopy showed that sperm transfer occurs in three phases which can be differentiated to 10 different stages. Sperm transfer occurs via a spermatophore which is extruded from the genital aperture of the male and is then transferred to the socket on the third pair of legs of the male, before being transferred into the spermathecae of the female via the spermathecal spines. This is the first observation of a spermatophore in Argulus.     

Habituation,reinstatement and recovery of predatory responses in two species of teleosts, Carassius auratus and Macropodus opercularis

The tendency for predatory responses to habituate and to be reinstated through sensitization and the passing of time was studied in two species of fish (the goldfish and the paradise fish). Prey (live brine shrimp), confined in a clear plastic tube were presented for short daily exposures to individual fish. Bites directed at the stimulus tube containing the prey were the primary response measure. In both species biting decreased significantly over the 6 days of the experiment. Reinstatement of the habituated response occurred by two means: (1) reinforcement (i.e. allowing the fish to chase and consume the prey), and (2) passing of time (10 days) with no intervening stimulation (recovery). Reinstatement could not be produced by presenting a novel stimulus, nutritive stimuli, nor by a shorter recovery interval.     

洞庭湖水系沅水和澧水野鲫的染色体组型及资源保护

鲫(Carassius auratus)是洞庭湖水系一种重要的经济鱼类。为了解洞庭湖水系野鲫的细胞遗传背景,采用PHA和秋水仙素活体注射法,对沅水和澧水采集的野鲫样本逐一进行肾细胞染色体制片及组型分析。结果发现,在两条河流的野鲫群体中均检测出染色体数为100和基本染色体数为150的两种不同倍性个体,其中,两条河流染色体数为100的二倍体鲫组型公式为2N=28M+22SM+28ST+22T,NF=150;基本染色体数为150的三倍体鲫组型公式为3N=42M+33SM+42ST+33T,NF=225。在沅水和澧水不同采样点随机采集的共100尾野鲫中,检测出的三倍体比例(85%)远高于二倍体(15%),且二倍体与三倍体鲫个体在形态特征上不存在明显差异(P0.05)。两种不同倍性鲫在同一水体的共存对于鲫的遗传进化与选育具有一定的理论和实践意义,而二倍体鲫种群的大量减少,则提示我们应该从染色体组遗传多样性角度加强对洞庭湖水系二倍体野鲫资源的保护。     

Anaerobic energy-metabolism of goldfish,Carassius auratus (L.)

Summary Goldfish, acclimated to 20°C and normal = 130 mmHg) and low ( = 19 mmHg) oxygen levels, were exposed to different periods of hypoxia and anoxia. Experiments were carried out at night. ATP, ADP, AMP, IMP, CrP, glycogen and lactate were determined in red muscle, white muscle and liver. Acclimation to hypoxia resulted in a marked increase of the energy charge of liver and red muscle and of the glycogen content of red and white muscle, indicating an increased anaerobic capacity. Short exposures to anoxia, up to 1 h, had little influence on the value of the measured parameters. Long-term exposures (12 h) to anoxia caused a significant decrease of CrP and glycogen levels in all tissues examined. The energy-charge of red and white muscle was hardly affected by a 12 h exposure to anoxia, but in liver tissue the energy charge decreased from 0.60 to 0.32. It is concluded that during anoxia muscle tissues are able to maintain high energy-charges, probably by means of a yet unknown anaerobic energy-producing system.Abbreviations CrP creatine phosphate - EC energy charge - IMP inosine monophosphate - I.U. International Unit (mole/min)     

The relationship between locomotor activity and sexual behaviour in ebony strains of Drosophila melanogaster

Male flies homozygous for the ebony¹¹ mutant allele suffer a severe visual impairment and consequently show poor mating success. However, ebony males show improved mating in darkness because they initiate courtship more quickly than in the light. They also exhibit a competitive superiority over wild-type males under darkened conditoons that correlates with the observed increase in the mutant's locomotor activity. Locomotor activity levels were subsequently shown to correlate with several indices of mating success under both dark and illuminated conditions. The evolutionary implications of this relationship between the two characters are discussed.     

Anaerobic energy metabolism of goldfish,Carassius auratus (L.)

Summary The concentrations of pyruvate, lactate, oxalo-acetate, aceto-acetate -hydroxybutyrate, -ketoglutarate, glutamate, NH ₄ ⁺ , NAD⁺ and NADH were measured in goldfish tissues after previous conditioning to normal and anoxic (12h) conditions. For 11 different metabolites efficiency of different extraction methods was tested by means of internal standards. The recoveries were generally over 80%. The substrate/product couples of the reactions catalysed by lactate dehydrogenase, malate dehydrogenase, -hydroxybutyrate dehydrogenase and glutamate dehydrogenase were used as redox parameters. In the lateral red muscle the redox state did not change during 12 h of anoxia. In the dorsal white muscle only the cytoplasmic redox state underwent a change, as indicated by the increase of the lactate/pyruvate ratio from 20 to 110. In liver both cytoplasm and mitochondria were reduced during anoxia. From the measured values the NAD⁺/NADH ratio was found to change only in white muscle, while the calculated free NAD⁺/NADH ratios were reduced in anoxic white muscle cytoplasm, anoxic liver mitochondria, and anoxic liver cytoplasm. Oxalo-acetate concentrations calculated from the equilibrium constants of lactate dehydrogenase and malate dehydrogenase were at least one order of magnitude smaller than the measured values. The data obtained from anoxic goldfish are in contrast to available data on other animals and support earlier reports which indicate that this animal has a special anaerobic metabolism. The results are discussed especially with respect to the role of ethanol as a sink for reducing equivalents.Abbreviations LDH lactate dehydrogenase - MDH malate dehydrogenase - HBDH -hydroxybutyrate dehydrogenase - GIDH glutamate dehydrogenase     

The effect of calcium on gill potentials and on sodium and chloride fluxes in the goldfish,Carassius auratus

Summary Measurements of electric potential and of sodium and chloride effluxes were carried out on a freshwater fish, the goldfishCarassius auratus. The potential was affected by a number of inorganic ion species but that with the most significant influence on transepithelial potential was calcium. The potential was about 10 mV negative in the absence of calcium and about 10 mV positive in the presence of 10 mM/l calcium. Sodium and chloride efflux rates were greatly reduced upon the addition of calcium to the medium. The origin of the transepithelial potential is discussed in terms of the relative permeability of the branchial membranes to sodium and chloride and the factors influencing these permeabilities.     

Effect of the odour of vaginal secretion on non-copulatory behaviour of male hamsters (Mesocricetus auratus)

Male hamsters were exposed to female vaginal secretion (in the absence of the female). When subsequently tested with females, their behaviour was determined by whether the test female matched or did not match the vaginal secretion. Less time was spent with mismatching females and less sniffing and licking was directed towards them. The effect of vaginal odour was present up to 3–4 h after the last contact with the secretion. The number of encounters with the vaginal odour and the spacing between them was important in determining the response to mismatching females. Contact with the vaginal secretion as opposed to its volatile components alone was necessary for the discrimination to occur. Discussion centres around the role of the vomeronasal organ and possible physiological pathways underlying the effect.     

Experimental analysis of the locomotor behaviour of Schistocerca gregaria induced by odour

The locomotor behaviour of the desert locust in response to volatile chemicals released from grass as a food plant was investigated in a wind tunnel. When bruised grass was at the windward end of the tunnel the insects responded by moving upwind towards the grass. The response was maximal for locusts starved for 4 hr or longer. Feeding just prior to an experiment inhibited the response; the degree of inhibition of the response, as estimated by the proportion of larvae responding, increased with the duration of the feeding period. All the larval instars and adults reacted in essentially the same way, but the response varied in the course of any one instar, there being more response in the first half of the instar—that is, the period preceding peak food intake—than later.     

水产用聚维酮碘对异育银鲫养殖的安全性评价

评价水产用聚维酮碘对异育银鲫(Carassius auratus gibelio)养殖的安全性,为其在异育银鲫养殖中的安全应用提供了重要的科学依据,本研究参照国家标准及相关法规,在观察了聚维酮碘对小球藻(Chlorella sp.)生长抑制作用、对水产益生菌抑菌效果以及对大型蚤(Daphnia magna straus)、斑马鱼(Brachydanio rerio)和异育银鲫的急性毒性的基础上,分析其对异育银鲫及其养殖水体主要有害理化因子的影响.实验结果表明,聚维酮碘在终浓度为6.00 ～ 14.00 mg/L时对小球藻生长具有促进作用,对小球藻的半数抑制浓度大于14.00 mg/L,对水产益生菌的最小抑菌浓度为128～512 mg/L,对大型蚤、斑马鱼的半数致死浓度分别为13.44 mg/L、17.63 mg/L.此外,聚维酮碘对异育银鲫的半数致死浓度为74.77 mg/L,而且在养殖水体中加入聚维酮碘至终浓度为0.20 ～ 1.40 mg/L后14 d内,随着聚维酮碘浓度的增加,各浓度组异育银鲫养殖水体的氨氮含量、亚硝酸盐含量均缓慢下降.本研究证实聚维酮碘低毒,但考虑到其可能对异育银鲫养殖水体中大型蚤等浮游动物存在潜在影响,建议其在异育银鲫养殖中的安全应用浓度应不高于1.34 mg/L,在该安全应用浓度内不会引起养殖水中氨氮、亚硝酸盐等有害因子含量的增加.     

Time-dependent effects of leptin on food intake and locomotor activity in goldfish

The present study investigates the possible circadian dependence of leptin effects on food intake, locomotor activity, glycemia and plasma cortisol levels in goldfish (Carassius auratus). Fish were maintained under 12L:12D photoperiod and subjected to two different feeding schedules, one group fed during photophase (10:00) and the other one during scotophase (22:00). Leptin or saline were intraperitoneally injected at two different times (10:00 or 22:00), coincident or not with the meal time. To eliminate the entraining effect of the light/dark cycle, goldfish maintained under 24 h light (LL) were fed and leptin-injected at 10:00. A reduction in food intake and locomotor activity and an increase in glycemia were found in goldfish fed and leptin-injected at 10:00. No significant changes in circulating cortisol were observed. Those effects were not observed when leptin was administered during the scotophase, regardless the feeding schedule; neither in fish maintained under LL, suggesting that a day/night cycle would be necessary to observe the actions of leptin administered during the photophase. Changes in locomotor activity and glycemia were only observed in goldfish when leptin was injected at daytime, coincident with the feeding schedule, suggesting that these leptin actions could be dependent on the feeding time as zeitgeber. In view of these results it appears that the circadian dependence of leptin actions in goldfish can be determined by the combination of both zeitgebers, light/dark cycle and food. Our results point out the relevance of the administration time when investigating regulatory functions of hormones.     

Molecular cloning and characterization of cat, gpx1 and Cu/Zn-sod genes in pengze crucian carp (Carassius auratus var. Pengze) and antioxidant enzyme modulation induced by hexavalent chromium in juveniles

Hexavalent chromium (Cr^6 +) is a common pollutant transient metal with high toxicity in the environment. The toxicological effects partly result from oxidative damage due to the production of excessive reactive oxygen species (ROS) in the reductive process of Cr^6 +. To explore the influence of ROS induced directly by Cr^6 + on the oxidative stress generation and antioxidant system, the full length cDNAs of antioxidant-related genes cat, gpx1 and Cu/Zn-sod were successfully acquired from pengze crucian carp first and analyzed. Furthermore, the mRNA expression of the antioxidant genes encompassing catalase (cat), copper/zinc superoxide dismutase (Cu/Zn-sod) and glutathione peroxidase (gpx1), antioxidant enzyme activities of CAT, SOD, and GPx and total protein content were further studied in the gill, intestine and liver of pengze crucian carp (Carassius auratus var. Pengze) juveniles upon acute exposure to Cr^6 + at concentrations of 0.1, 1.0, 10 and 100 mg/L for 4 days. Differential significant changes of the antioxidant enzymes and gene expression were observed in different tissues. The findings contribute to better understanding the antioxidant mechanisms induced by Cr^6 + and selecting the organic-specific sensitive biomarkers to monitor the safety of the aquatic ecosystem.