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1.
A translucent collagen gel was formed from a transparent acidic solution of red stingray collagen by adjusting to physiological ionic strength and pH in phosphate buffer and then incubating at 25–37°C. During fibril formation from red stingray collagen, the turbidity increased when the NaCl concentration was increased at constant pH and the rate of fibril formation was accelerated by higher pH or lower NaCl concentration. The T m of red stingray collagen fibrillar gel was estimated as 44.3 ± 3.5°C, which was higher than that of the collagen solution, 33.2°C. In addition, red stingray collagen gel maintained its shape without melting and was suitable for culture of mouse stromal cells at 37°C.  相似文献   

2.
Atlantic stingrays, Dasyatis sabina, are common residents of shallow-water seagrass habitats that experience natural cycles of severe hypoxia during summer months. We hypothesized that stingrays exposed to hypoxic episodes would improve their hypoxia tolerance by increasing branchial surface area and altering blood oxygen-carrying capacity. To this end, we compared critical oxygen minimum, gill morphology, and hemoglobin/hematocrit levels in a control group of Atlantic stingrays held at continuous oxygen saturations of 80–90 % (≥5.5 mg/l), to treatment groups exposed to a 7-h hypoxic interval at 55 % (~4.0 mg/l), or 30 % oxygen saturation (~2.0 mg/l). Stingrays in hypoxic treatment groups significantly improved their hypoxia tolerance. Critical oxygen minimum values fell from 0.7 ± 0.11 mg/l in control fish to 0.4 ± 0.05 and 0.4 ± 0.06 mg/l in the 55 and 30 % saturation treatment groups, respectively. Mass-specific gill surface area between control fish and the 30 % saturation treatment group increased by 1.7-fold, from 85 to 142 mm2/g. Although stingrays did not show an increase in hematocrit or hemoglobin levels, production of more efficient hemoglobin isoforms could not be ruled out. An increase in hypoxia tolerance allows Atlantic stingrays to forage for longer times and across a wide range of hypoxic habitats that are less accessible to predators and competitors.  相似文献   

3.
Climate change is predicted to increase the average water temperature and alter the ecology and physiology of several organisms including fish species. To examine the effects of increased water temperature on freshwater fish reproduction, adult European bullhead Cottus gobio of both genders were maintained under three temperature regimes (T1: 6–10, T2: 10–14 and T3: 14–18°C) and assessed for gonad development (gonadosomatic index—GSI and gonad histology), sex steroids (testosterone—T, 17β-estradiol—E2 and 11-ketotestosterone—11-KT) and vitellogenin (alkali-labile phosphoprotein phosphorus—ALP) dynamics in December, January, February and March. The results indicate that a 8°C rise in water temperature (T3) deeply disrupted the gonadal maturation in both genders. This observation was associated with the absence of GSI peak from January to March, and low levels of plasma sex steroids compared with T1-exposed fish. Nevertheless, exposure to an increasing temperature of 4°C (T2) appeared to accelerate oogenesis with an early peak value in GSI and level of plasma T recorded in January relative to T1-exposed females. In males, the low GSI, reduced level of plasma 11-KT and the absence of GSI increase from January to March support the deleterious effects of increasing water temperature on spermatogenesis. The findings of the present study suggest that exposure to elevated temperatures within the context of climate warming might affect the reproductive success of C. gobio. Specifically, a 4°C rise in water temperature affects gametogenesis by advancing the spawning, and a complete reproductive failure is observed at an elevated temperature of 8°C.  相似文献   

4.
Ninety‐three giant Queensland grouper, Epinephelus lanceolatus (Bloch), were found dead in Queensland, Australia, from 2007 to 2011. Most dead fish occurred in northern Queensland, with a peak of mortalities in Cairns in June 2008. In 2009, sick wild fish including giant sea catfish, Arius thalassinus (Rüppell), and javelin grunter, Pomadasys kaakan (Cuvier), also occurred in Cairns. In 2009 and 2010, two disease epizootics involving wild stingrays occurred at Sea World marine aquarium. Necropsy, histopathology, bacteriology and PCR determined that the cause of deaths of 12 giant Queensland grouper, three wild fish, six estuary rays, Dasyatis fluviorum (Ogilby), one mangrove whipray, Himantura granulata (Macleay), and one eastern shovelnose ray, Aptychotrema rostrata (Shaw), was Streptococcus agalactiae septicaemia. Biochemical testing of 34 S. agalactiae isolates from giant Queensland grouper, wild fish and stingrays showed all had identical biochemical profiles. The 16S rRNA gene sequences of isolates confirmed all isolates were S. agalactiae; genotyping of selected S. agalactiae isolates showed the isolates from giant Queensland grouper were serotype Ib, whereas isolates from wild fish and stingrays closely resembled serotype II. This is the first report of S. agalactiae from wild giant Queensland grouper and other wild tropical fish and stingray species in Queensland, Australia.  相似文献   

5.
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6.
Freshwater adaptability of chum salmon was examined in juvenile fish reared in seawater for 4 months. The fish, weighing about 40g, were transferred directly to fresh water in October, when their cohorts are migrating in the North Pacific Ocean. Plasma sodium concentration decreased from 167 mM in seawater to about 130 mM during the first 24h, and increased gradually during 2–7 days after the transfer. No immunoreactive prolactin (PRL) was detected in the plasma of the seawater-adapted fish nor during the first 24h in fresh water. Significant levels of PRL were detected after 2–3 days. The maximal level (2.6 ng/ml) was observed after 5 days and became undetectable again after 7 days; no significant correlation was seen between the changes in plasma sodium and PRL levels during the transfer. Plasma growth hormone levels were relatively constant, except for a significant decrease 12h after the transfer. Although plasma thyroxine levels were highly variable during the experiment, a significant decrease and an increase were observed 12h and 5 days after the transfer, respectively. The present study indicates that juvenile chum salmon retain hyperosmoregulatory ability even after prolonged rearing in seawater. Examination of turnover rates, rather than changes in plasma levels, seems to be essential to clarify the osmoregulatory roles of the hormones.  相似文献   

7.
Vitellogenin (VTG) was purified from the plasma of estradiol-17β (E2) treated male brook trout (Salvelinus fontinalis; bt) using gel filtration and anion exchange chromatography. An antiserum to bt-VTG was raised in rabbits, then used to detect bt-VTG by Western blot analysis. Purified bt-VTG and its antibody were then used to develop an antibody-capture, competitive enzyme-linked immunosorbant assay (ELISA). Confirmation of the purified protein as bt-VTG was based on the characteristics of high molecular weight (∼562 kDa), dominant plasma protein in vitellogenic females and induction by exogenous E2 treatment in males. The antiserum recognized a major 184 kDa polypeptide as well as minor bt-VTG degradation products (150–66 kDa) in purified bt-VTG and in plasma from vitellogenic females. Low levels of antibody cross reactivity were shown with plasma from nonvitellogenic females, control rabbit serum, and several other antisera known to not contain VTG. The ELISA had a minimum detection limit of 8 ng ml−1 and intra- and inter-coefficients of variation less than 9% and 15%, respectively. The ELISA demonstrated parallel binding slopes among dilution curves of purified bt-VTG standard and plasma from diploid and triploid brook trout females. Using the ELISA, maximum plasma VTG levels of 93.5±33.6 mg ml−1 were detected in vitellogenic diploid females, whereas only 0.18±0.15 mg ml−1 were detected in triploid females of the same age (n=5 for each). Diploid and triploid males cohabitating with vitellogenic females showed measurable levels of plasma VTG during vitellogenesis in females (i.e., 0.17 and 0.06 mg ml−1, respectively (n=1)). This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

8.
Vitellogenin (Vtg) has proven to be a sensitive and simple biomarker in determining sex, sexual maturity, and xenoestrogenic effects in fish. Thus, our investigation has been focused on identification, partial characterization, and quantification of grey mullet (Mugil cephalus) Vtg through the use of a variety of biochemical and immunological analytical techniques. Mullet is considered both a promising aquaculture candidate and an important species for improving sediment quality in polyculture systems. In the first part of this work, grey mullet Vtg was purified from plasma of 17β-estradiol (E2)-induced male fish by a one-step chromatographic protocol, and partially characterized. Specific polyclonal antibodies were then raised against the mullet Vtg, and both an indirect ELISA and an optical immunosensor were set up and validated to quantify plasma Vtg. The indirect ELISA and the optical immunosensor assay developed showed linear measuring in the range 56.8–1047.1 ng mL−1 and 70–739 ng mL−1 Vtg concentrations in standard solutions, respectively. The results obtained suggest that the indirect ELISA allows Vtg detection over a wide dynamic range, thus resulting more suitable for rapid and sensitive sample screening. Therefore, we suggest that the direct immunosensor is a promising tool which needs more investigation to improve the sensitivity.  相似文献   

9.
Fishes display a wide variation in their physiological responses to stress, which is clearly evident in the plasma corticosteroid changes, chiefly cortisol levels in fish. In the present study, we describe a novel label-free immunosensor for detecting plasma cortisol levels. The method is based on immunologic reactions and amperometric measurement using cyclic voltammetry. For the immobilization of the antibody on the surface of sensing electrode, we used a self-assembled monolayer of thiol-containing compounds. Using this electrode, we detect the CV signal change caused by the generation of antigen–antibody complex. The immunosensor showed a response to cortisol levels, and the anodic peak value linearly decreased with a correlation coefficient of 0.990 in diluted plasma. The specificity of the label-free immunosensor system was investigated using other steroid hormones, such as 17α, 20β-dihydroxy-4-pregnen-3-one, progesterone, estriol, estradiol, and testosterone. The specific detection of cortisol was suggested by a minimal change from ?0.32 to 0.51 μA in the anodic peak value of the other steroid hormones. The sensor system was used to determine the plasma cortisol levels in Nile tilapia (Oreochromis niloticus), and the results were compared with those of the same samples determined using the conventional method (ELISA). A good correlation was obtained between values determined using both methods (correlation coefficient 0.993). These findings suggest that the proposed label-free immunosensor could be useful for rapid and convenient analysis of cortisol levels in fish plasma samples.  相似文献   

10.
A monoclonal antibody (designated MAb-007) was produced against the pathogenic haemoflagellate Cryptobia salmositica Katz. This IgG3 antibody recognized the 47-kDa antigenic polypeptide of C. salmositica (SDS-PAGE and Western immuno-blotting). The antibody did not agglutinate live parasites, and there was no change in the staining intensity of the 47-kDa band on Western immunoblots after immunoabsorption of MAb-007 with live intact parasites. The 47-kDa antigen recognized by MAb-007 was localized in the cytoplasm of the parasite (immunogold labelling and electron microscopy). The monoclonal antibody cross- reacted with the 47-kDa polypeptides of C. bullocki Srrout and C. catostomi Bower & Woo. It was used in an antigen-capture ELISA for the detection of parasite antigen in the plasma of rainbow trout inoculated with the parasite, or with an attenuated vaccine strain of C. salmositica. All pre-infection plasma were negative while all infected fish with detectable parasitaemias were positive for antigen at 1–9 weeks after infection. Parasite antigen was even detected in vaccinated fish that were negative for parasites using the wet mount microscopic technique. The antigen-capture ELISA detected C, salmositica antigen in whole cell lysate preparations at concentrations as low as 0.5 μg ml-1. Fifty microlitres of fish plasma was required in the antigen-capture ELISA, and the use of a plate reader and 96-well plates facilitated rapid analysis of a large number of plasma samples. The sensitivity of the assay makes it a potentially useful tool for detection of Cryptobia infections.  相似文献   

11.
A label-free immunosensor for detecting the oocyte maturation-inducing hormone 17, 20β-dihydroxy-4-pregnen-3-one (DHP), was developed. A principle of the sensor system was based on differences in electrochemical activity changed by an immunoreaction in the absence and presence of DHP. For preparation of the immunosensor, anti-DHP IgG was immobilized on an Au working electrode modified with a self-assembled monolayer of 3-mercaptopropionic acid. The sensor was immersed into a sample solution containing DHP. DHP was determined by cyclic voltammetry. The immunosensor showed a specific response to DHP, and the oxidation peak current linearly decreased in the range of 7.8–500 pg ml−1 with a correlation coefficient of 0.996. The sensor system was applied to determine the DHP levels in plasma of goldfish and was compared with the DHP levels of the same samples determined using an ELISA as the conventional method. Good correlation was obtained between values determined using both methods in the range of 0.1–7.7 ng ml−1 (correlation coefficient 0.876). These findings suggest that the proposed label-free immunosensor can be used to analyze DHP levels in fish plasma samples.  相似文献   

12.
Black Scorpion fish (Scorpaena porcus Linnaeus 1758) caught during monthly sampling carried out in 2003 in the Dardanelles, Turkey, were examined for the parasite. Trachelobdella lubrica. Infested fish were caught only during December 2003, and the clinical conditions of the 12 fish naturally infested with T. lubrica included fin rot, swollen foci of skin and haemorrhages of the gill and abdominal skin. The prevalence, intensity and abundance of infestation in December 2003 were 40%, 1.75 and 0.70, respectively. The average hepatosomatic index of the infested fish was lower than that of noninfested fish, while the means of the kidney index, splenosomatic index, condition factor, body weight and length were not significantly different between the infested and noninfested fish groups. Blood analysis was conducted on 12 naturally infested and 12 healthy (noninfested) Black Scorpion fish to determine the possible characteristic changes in blood parameters of the fish in response to natural infestation with T. lubrica. Blood leucocyte counts, haematocrit levels, serum total protein, albumin phosphorus, urea, glucose, globulin, cholesterol and triglyceride concentrations in naturally infested Black Scorpion fish were significantly less than those of the noninfested fish (p < 0.05). No significant decreases were observed in the serum sodium, iron, calcium, potassium, chlorine, blood urea nitrogen and creatinine values of the naturally infested fish. Blood haemoglobin values, erythrocyte counts and serum glutamate aspartate aminotransferase (glutamate oxalacetate transaminase), alanine aminotransferase (glutamate pyruvate transaminase), uric acid and very low-density lipids levels of infested fish were insignificantly greater than those in healthy fish.  相似文献   

13.
For surface disinfection of marine fish eggs Buffodine (1.06% free iodine), glutaraldehyde, chloramine-T and sodium hypochlorite (5% free chlorine) were tested using plaice (Pleuronectes platessa L.) as the main species for evaluation. Glutaraldehyde was the most promising candidate of the four chemicals tested. Good bactericidal effects without any documented negative effects on eggs and larvae were obtained at concentrations of 400–600 mg l–1 and contact times of 5–10 min. Replicated experiments under identical disinfection conditions revealed a clear correlation between the degree of successful surface disinfection and the initial bacterial load of the egg batch.  相似文献   

14.
Radioimmunoassay measurement of pituitary AVT content and plasma AVT concentration indicated comparable levels in fully adapted sea water (SW) and fresh water (FW) flounders. Circulating AVT represented less than 0.1% of the pituitary AVT reserve. The urophysis contained AVT but the total content was only 2 or 3 fold that of circulating AVT. In fish adapted to hypertonic media, there was a close correlation between plasma AVT concentration and plasma Na+ concentration or osmolality. The present study examined the effects of acute osmotic challenge, associated with FW to SW transfer, and the influence of extracellular fluid volume status on AVT secretion. Short-term transfer of fish from FW to SW (up to 3 days) did not evoke a clear change in plasma AVT levels, though pituitary content was reduced at 24 h. During the first 3 days after transfer to SW, only small increments in plasma tonicity were apparent. The sensitivity of AVT secretion to osmotic stimuli may only be expressed when plasma osmolality has exceeded a specific threshold, which was probably not reached in these transfer studies. Fish in hypotonic media showed no relationship between plasma osmolality/tonicity and plasma AVT concentration. Acute extracellular fluid volume expansion of SW adapted fish also abolished the normally observed relationship between plasma osmolality and AVT concentration in these hypertonic media fish. This trend indicates that volume status may modulate the sensitivity of AVT secretion to osmotic stimuli as occurs in tetrapods.  相似文献   

15.
吉富罗非鱼IGF-1基因的基因型对生长和体型的影响   总被引：1，自引：0，他引：1  
通过比对6尾吉富罗非鱼(Genetically Improved Farmed Tilapia,GIFT)的胰岛素样生长因子1(Insulin-like Growth Factor 1,IGF-1)基因外显子1-部分内含子2和外显子3-部分内含子4序列,共找到3个SNPs位点,分别为内含子1_A1307G、内含子1_G1319T和内含子3_C6T.使用PCR-RFLP法检测了5个家系共121尾吉富罗非鱼在内含子1_A1307G和内含子3_C6T的基因型,分析不同基因型与生长性状的相关性.结果表明,内含子1_A1307G与雌鱼增重和体厚/体长值均显著相关(P＜0.05),但与雄鱼的相关性不显著(P＞0.05);内含子3_C6T与雄鱼和雌鱼的增重分别呈显著(P＜0.05)和极显著相关(P＜0.01),与雌鱼体高/体长显著相关(P＜0.05).为了验证所选标记在其他家系的表现,本实验检测了来自60个家系的417尾吉富罗非鱼在内含子1_A1307G、内含子3_C6T的基因型与增重性状的相关性,结果具有相同趋势.本实验筛选到与吉富罗非鱼体型和增重相关的SNP位点2个,可作为辅助育种标记.  相似文献   

16.
Antimicrobial polypeptides (AMPPs) are increasingly recognized as a critical component of innate host defense. Among the AMPPs, polypeptides related to histones have been identified from many animals. Using peptide mapping, we further confirm the identity of two histone-like proteins from fish as members of the H2B (sunshine bass) and H1 (rainbow trout) histone groups. We optimized the conditions for measuring rainbow trout HLP-1/H2B via sandwich ELISA. We used two antibodies, one to the amino terminus and one to the carboxyl terminus, of trout histone H2B, as the capture antibodies, and we used peroxidase-labeled antibody raised to calf histone H2B as the secondary antibody. Specificity of the detecting antibody was confirmed by specific reactivity with histone H2B in tissue extracts via western blotting. The test was reproducible and capable of detecting as little as 5 ng of histone H2B (0.05 μg/ml). Histone H2B levels expressed in gill tissue of juvenile, healthy rainbow trout were well within concentrations that are lethal to important fish pathogens. However, there was a significant, age (size)-dependent decline in histone H2B concentrations as fish matured, until levels became virtually undetectable in market-size fish. In contrast, levels in skin appeared to remain high and unchanged in small versus large fish. Antibacterial activity in skin and gill tissues was closely correlated with histone H2B concentration measured via ELISA, which supports our previous finding that histones are the major AMPPs in rainbow trout skin and gill.  相似文献   

17.
Variation in individual size has important consequences for a number of characteristics of fish, which can impact fish populations. The impact of fish size on recovery following exercise, however, is poorly understood, with little information existing on the recovery of ionic/osmotic variables. The goal of this study was to quantify not only how allometry impacts the magnitude of physiological disturbance following burst exercise in largemouth bass (Micropterus salmoides), but also how allometry impacts the time required for exercise-induced disturbances to return to baseline levels. To accomplish this goal, two size classes of largemouth bass (large = 772–1,441 g total weight, mean = 1,125 g; small = 93–238 g, mean = 148 g) were exercised for 60 s and allowed to recover for 0, 1, 2, or 4 h before being sampled for plasma and white muscle. Large largemouth bass exhibited elevated concentrations of plasma glucose and sodium relative to small fish following a common exercise challenge. Large fish required additional time to clear metabolic disturbances in plasma and failed to restore potassium to basal levels even following 4 h of recovery, indicating an improved ability of the smaller fish to recover from disturbances. Results are further discussed in the context of physiological ecology and fitness for largemouth bass.  相似文献   

18.
Trimethylamine oxide (TMAO), which has previously not been known to occur in significant amounts in the blood of marine teleosts, rose to concentrations of approximately 50 mM in the blood of winter-acclimatized rainbow smelt, Osmerus mordax. Urea also increased in the blood of cold-acclimatized smelt, and, with TMAO, contributed significantly to the winter freezing point depression. TMAO and urea also varied seasonally in muscle and liver tissues. TMAO and urea appeared to be reabsorbed from the urine. Losses of TMAO and urea from the head region of the fish, where most of the losses appeared to occur, were approximately 9 μmol and 8 μmol 100 g−1 h−1, respectively. Despite the effluxes, TMAO and urea levels in both the blood and muscle either increased or were maintained in starved, cold-acclimated fish, suggesting that they were synthesized in response to cold temperature. TMAO was also found in the blood of some other cold-hardy teleosts.  相似文献   

19.
Vitellogenin (Vtg) was purified from the plasma of 17-estradiol (E2)-injected male greenback flounder,Rhombosolea tapirina. The molecular weight of the native Vtg was estimated by gel filtration as 540 kD. SDS-PAGE and Western blotting analyses indicated that this protein consisted of three bands with molecular weights of 155, 104, 79 kD, respectively. A polyclonal antibody against the highest molecular weight band of putative Vtg was generated in sheep and an indirect antibody-capture competitive enzyme-linked immunosorbent assay (ELISA) was developed. The assay was validatedfor plasma Vtg measurement in greenback flounder. Serial dilutions of plasma from vitellogenic females parallelled the standard Vtg curve, whereas no cross-reaction was observed with the plasma of males in the ELISA. The Vtg ELISA was used to assess the induction of Vtg by E2 in vivo in males. The induction of Vtg in greenback flounder showed a time- and dose-dependent response as in other species. In E2-treated fish, detectable levels of Vtg were first found at 48 h, and reached a peak at 96 h post-injection. Plasma levels of Vtg increased as the E2 dose increased with a threshold of 0.1 mg kg–1.  相似文献   

20.
The main objective of the present study was to evaluate whether dietary supplementation of urea might reduce the incidence of winter ulcer in sea water-farmed Atlantic salmon. Salmon destined to be S0 smolt were fed with a urea-supplemented diet (0 or 20 g kg−1 urea) over an 8-week period prior to sea water transfer and were then fed supplemented diet (0, 5, 10 or 20 g kg−1 urea) during the first and second winters in the sea. During the first winter positive relationships between dietary urea and plasma urea and between plasma urea and plasma osmolality were observed. Further, plasma osmolality displayed a negative relationship to mortality. Of the salmon that died during the first winter in the sea 90% had one or more skin ulcers. Both during the first and second winter there were fewer salmon with ulcer among fish fed with the diets supplemented with urea. Salmon fed with 20 g kg−1 urea tended to have higher percentage water in the muscle. Mortality and incidence of salmon with ulcer seemed to relate to plasma osmolality amongst fish fed on diets that differed in levels of urea supplementation, suggesting that an osmotic imbalance may contribute to the development of winter ulcer in farmed salmon. Salmon fed with 20 g kg−1 urea showed significantly greater body weight during the second winter in sea. Fish killed without prior starvation had significantly higher level of muscle urea in the 20 g kg−1 urea group compared with fish fed with the unsupplemented diet. However, a 13-day starvation period reduced urea content in the muscle to the level of the control. No effects of dietary urea supplementation on the sensory quality of market size Atlantic salmon were observed.  相似文献   

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