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1.
The distribution of branchial carbonic anhydrase (CA) in the shark, Squalus acanthias, was studied using in situ measurements of pH disequilibrium states in post-branchial saline, and immunological techniques, immunofluorescence microscopy and Western analysis, employing rabbit polyclonal antibodies against rat pulmonary membrane associated CA IV and chick retinal cytosolic CA II. In the in situ saline perfused gill preparation, the CA inhibitor acetazolamide produced a pH disequilibium (0.063 ± 0.022 pH units) while control and bovine carbonic anhydrase perfusions did not (0.012 ± 0.017 and 0.023 ± 0.018 pH units, respectively). These results indicate that the HCO3 - dehydration reaction is accelerate by endogenous extracellular CA. Western analysis of saline perfused gill membrane preparations revealed an immunoreactive 48 kDa band with the CA IV probe. In crude gill homogenates, a 33 kDa and 31 kDa pair of bands is identified by the CA II probe. The pattern of immunolabeling for CA II in the gill epithelium was either diffuse or punctate within both lamellar and filament epithelial cells while eyrthrocytes and pillar cells displayed a diffuse staining pattern.  相似文献   

2.
The pseudobranch in rainbow trout was investigated in order to clarify its metabolic and physiological function. Contents of lactate, glycogen, and glycerides and activities of carbonic anhydrase (CA), lactate dehydrogenase (LDH), and 3-hydroxy-acyl CoA dehydrogenase (HAD) were measured and compared with those in the gills and liver. Contents of lactate and glycerides, and activities of CA and HAD were higher in the pseudobranch than in the gills and liver. The results show that the pseudobranch is well equipped with enzymes (HAD and CA) suggested to be coupled to fatty acids breakdown and synthesis respectively. Lactic acid, possibly formed from glycogen and the glycerol component in glycerides, may be involved in the increase in blood P0 2 (Root effect) that is necessary to meet the oxygen needs of the eye. Pseudobranch carbonic anhydrase is probably involved in this process.  相似文献   

3.
The cardiovascular effects of the kallikrein-kinin system (KKS) have not been completely characterized in lower vertebrates. In the present study, a specific, irreversible kallikrein inhibitor, Phe-Phe-Arg-chloromethyl ketone (PPACMK) was used to examine: 1. the role of the KKS in blood pressure regulation in vivo; 2. the nature of the pressor substance formed by the action of kallikrein on trout plasma in vivo and in vitro; and 3. the presence of kallikrein in trout gills and kidney. Dorsal aortic cannulated rainbow trout were used for in vivo blood pressure assays and two colorimetric serine-protease assays were used to examine tissue kallikrein activity. PPACMK alone had no effect on blood pressure in vivo. Pretreatment of porcine kallikrein with PPACMK inhibited the enzyme's pressor effect in trout by 80% and significantly attenuated the synthesis of vasopressor substance(s) from heat-treated trout plasma in vitro. Approximately 30% of gill serine protease activity was inhibited by pretreatment with PPACMK; no PPACMK-sensitive kallikrein activity was observed in the kidney. Salt water adaptation did not affect kallikrein-specific activity in the gill. These results show that the salmonid KKS does not appear to be involved in the regulation of systemic blood pressure. Further, the formation of pressor substances from trout plasma in vivo and in vitro is due to kallikrein activity and the peptides generated are similar. A kallikrein, similar to the mammalian enzyme, is found in trout gills, suggesting that the salmonid KKS may be a local mediator of gill function.  相似文献   

4.
The fluid uptake rate of the posterior intestine of salmonids increases during the parr-smolt transformation. Intestinal fluid uptake in post-smolt Atlantic salmon was investigated after treatment with cortisol and growth hormone (GH), alone or together. Two replicate experiments were conducted in August 1991 and August 1992. Cortisol was emulsified in vegetable shortening and vegetable oil (1:1) and implanted into the peritoneal cavity. GH was administered as intraperitoneal injections in a saline vehicle on days 0 and 2. On days 5 and 6, plasma cortisol levels, gill Na+,K+-ATPase activity, andin vitro measurements of fluid transport rate (Jv) across the posterior intestine were measured. Implants of cortisol elevated the plasma cortisol levels within a physiological range, and resulted in elevated gill Na+,K+-ATPase activity, as expected. The fluid uptake rate across the posterior intestine was roughly doubled by cortisol treatment. GH treatment did not affect intestinal fluid transport, gill Na+,K+-ATPase activity, or plasma cortisol concentrations. The seawater-adapting increase in the rate of fluid uptake by the posterior intestine of smolting salmon is probably stimulated by elevated plasma cortisol concentrations.  相似文献   

5.
为了探讨盐碱胁迫条件下鱼类渗透生理调节机制,以尼罗罗非鱼(Oreochromis niloticus)为实验材料, PCR扩增得到了Na+/HCO3-共转运子(NBCe1)基因cDNA部分序列,比较了单盐(盐度10、盐度15)、单碱(1.5 g/L、3 g/L NaHCO3)、盐碱混合(盐度10,碱度1.5 g/L;盐度15,碱度3 g/L)胁迫后不同时间(0 h、6 h、12 h、24 h、48 h、72 h、96 h)血清渗透压、离子浓度(Na+、K+、Cl-、Ca2+)以及鳃碳酸酐酶(CA)活性、CA与NBCe1基因mRNA表达变化。结果显示,不同胁迫条件下,血清渗透压、离子浓度、鳃组织CA酶活、CA与NBCe1基因mRNA表达变化均与胁迫强度呈正相关。随时间推移,血清渗透压、离子浓度呈现先上升后下降的变化趋势,单盐、盐碱混合组血清渗透压值较单碱组高。单盐、单碱、盐碱混合组中, NBCe1基因mRNA在鳃中均呈略微上调,但不显著(P>0.05)。单碱组和盐碱混合组鳃CA活性较单盐组高,低盐碱胁迫(盐度10,碱度1.5 g/L)下CA活性较晚达最高值;不同胁迫条件下, CA基因mRNA表达均表现上调,单碱、盐碱混合组更为显著(P<0.05),推测CA较NBCe1对体内HCO3-转运作用更为显著。研究结果为尼罗罗非鱼盐碱适应生理调节提供了基础资料。  相似文献   

6.
Accumulation of 14C in various tissues and organs was studied in three different groups of 0.8‐kg Atlantic salmon Salmo salar force‐fed with 14C1‐glucose in order to evaluate if metabolism of glucose depended on adaptation to dietary carbohydrate level. The salmon had been fed diets supplemented with 0, 100 and 200 g maize dextrin kg?1 for 10 months before the experiment. The fish were force‐fed 6.65 × 104 Bq of 14C1 glucose kg?1 BW, in gelatin capsules. Fish for analysis were obtained 16 h later. 14C was measured in blood plasma, gill, kidney, liver and white muscle, and in lipid extract of liver. The liver contained most 14C, followed by heart, blood plasma, gill and liver lipid extract, while kidney and muscle contained the least 14C per gram or millilitre tissue. The muscle contained most radioactivity, on an estimated total tissue basis, followed by liver, blood plasma, gill, liver lipid extract, kidney and heart tissue. Thirty‐eight per cent of the orally administered 14C was recovered in the salmon adapted to the diet without dextrin after 16 h. This was significantly (P < 0.05) higher than the 30% and 32% recovered in the salmon adapted to diets with 10% and 20% dextrin. This effect on adaptation to dietary dextrin level in glucose uptake or metabolism was supported by a trend (P < 0.10) toward higher radioactivity per gram or millilitre of each individual tissue in the fish adapted to the diet without dextrin, when compared with the other two adaptation regimes.  相似文献   

7.
Effects of adrenaline on the equilibrium distributions of Na+ , K+ , H+ , Cl– , and H2O across the cell membrane of rainbow trout (Salmo gairdneri) erythrocytes were determinedin vitro, as a function of P CO2 (1.76–7.77 torr). CO2-carrying capacity of the blood was also examined. Plasma catecholamine concentrations inunanaesthetized, unrestrained trout were 3.1 nM adrenaline and 1.2 nM noradrenaline. Elevation of the plasma adrenaline concentrationin vitro to 4.6 × 103 nM resulted in net gains of Na+ , Cl– and H2O by red cells, a net loss of H+ from red cells, and a pronounced red cell swelling. Adrenaline also reduced the CO2-carrying capacity of trout bloodin vitro. The magnitudes of these effects increased with PCO2 and, thus, were sensitive to blood HCO3 – concentrations. The distribution of K+ between red cells and plasma was unaffected by adrenaline. Adrenergic-mediated ion movements and red cell swelling were sensitive to both propranolol and SITS. These results are consistent with the symport NaCl uptake model for adrenergic-mediated swelling of Baroinet al. (1984). The adrenergic response of fish erythrocytes may function to ameliorate the effects of blood acidoses on O2-carrying capacity by maintaining red cell pH in the face of a decrease in plasma pH.  相似文献   

8.
We studied the physiological status of juvenile turbot (Scophthalmus maximus L.) under severe hypoxia (1 and 2 mg/L dissolved oxygen, DO), hypoxia (3 and 5 mg/L DO), hyperoxia (11 and 14 mg/L DO) and normoxia (7 mg/L DO, control) conditions. The respiratory rates, haematology parameters, acid–base balance status and gill structure were analysed to find the effects of different DO concentration on turbot. Fish mortality was only observed under severe hypoxia conditions. Severe hypoxia caused an increase in respiratory rates and red blood cell counts, as well as an increase in haemoglobin and haematocrit levels in the fish. In fish exposed to hypoxia conditions, the respiratory rate increased overall as the DO concentration decreased. Lower pCO2 and HCO3? levels led to a high blood pH, while the pO2 remained stable. In hyperoxia groups, respiratory rate decreased as the DO concentration increased. The levels of pCO2 and HCO3? significantly increased (P < 0.05), while the pO2 level and blood pH did not change obviously. The gill structure was damaged after prolonged exposure to hyperoxia, but no obvious damage was found in hypoxia groups. The fish that survived the hypoxia or hyperoxia treatment were able to restore the structural integrity of the gills after 14 days' recovery. The results suggest that juvenile turbots can tolerate a wide range of DO concentrations. However, even mild hyperoxia condition (11 mg/L DO), which is widely used in fish culture, has adverse effects on juvenile turbot physiology.  相似文献   

9.
Sanguinarine (SA), with antimicrobial and antiparasitic activities against fish pathogens, exhibits great potential commercial use in aquaculture. However, little information on pharmacokinetics of SA restricts further application in aquaculture. In this study, pharmacokinetics of SA in common carp (Cyprinus carpio) following a single intraperitoneal administration [10 mg kg?1 BW (body weight)] was evaluated by high‐performance liquid chromatography (HPLC). The peak concentration (Cmax) of SA in kidney was 11.8 μg g?1, which was higher than in other tissues and plasma. The terminal half‐life in fish tissue and plasma was as follows: 42.3 h (kidney) > 37.2 h (liver) > 20.1 h (gill) > 18.8 h (muscle) > 10.9 h (spleen) > 10.0 h (plasma). Additionally, we determined the bacterial loads in tissues of common carp infected with Aeromonas hydrophila after i.p. administration of SA at 0, 5, 10 and 20 mg kg?1 BW. The results showed that i.p. administration of SA at 10 mg kg?1 BW significantly enhanced antibacterial efficacy against A. hydrophila, where the antibacterial ratio in the gill, kidney, spleen and liver on day 5 was 95.13%, 93.33%, 90.09% and 92.82%, respectively. Overall, these results suggested the potential of SA to treat A. hydrophila infection in common carp farming industry.  相似文献   

10.
Life history theory suggests that maximum size and growth evolve to maximize fitness. In contrast, the Gill Oxygen Limitation Theory (GOLT) suggests that growth and maximum size in fishes and other aquatic, water-breathing organisms is constrained by the body mass-scaling of gill surface area. Here, we use new data and a novel phylogenetic Bayesian multilevel modelling framework to test this idea by asking the three questions posed by the GOLT regarding maximum size, growth and gills. Across fishes, we ask whether the body mass-scaling of gill surface area explains (1) variation in the von Bertalanffy growth coefficient (k) above and beyond that explained by asymptomatic size (W∞), (2) variation in growth performance (a trait that integrates the tradeoff between k and W∞) and (3) more variation in growth performance compared to activity (as approximated by caudal fin aspect ratio). Overall, we find that there is only a weak relationship among maximum size, growth and gill surface area across species. Indeed, the body mass-scaling of gill surface area does not explain much variation in k (especially for those species that reach the same W∞) or growth performance. Activity explained three to five times more variation in growth performance compared to gill surface area. Our results suggest that in fishes, gill surface area is not the only factor that explains variation in maximum size and growth, and that other covariates (e.g. activity) are likely important in understanding how growth, maximum size and other life history traits vary across species.  相似文献   

11.
In this study, CA I and II isoenzymes were purified from Van Lake fish gills by using Sepharose-4B-L-tyrosine-sulfanilamide affinity chromatography and to determine the effects of some metals on the enzyme activities. For purified CA I isoenzyme, yield, specific activity, and purification fold were obtained as 42.07%, 4948.12 EU/mg protein, and 116.61 and for CA II isoenzyme, 7%, 1798.56 EU/mg protein, and 42.38 respectively. Activity of CA was determined by measuring “CO2-hydratase activity”. Purity control was checked by SDS-PAGE. In vitro inhibitory effect of Cu2+, Ag+, Cd2+, Ni2+ metal ions, and arsenic (V) oxide were also examined for both isozymes activities. Whereas Cu2+, Ag+, Cd2+, and Ni2+ ions showed inhibitory effects on both isozymes, arsenic (V) oxide showed activation effect. IC50 values were calculated by drawing activity %-[I] graphs for metal ions exhibiting inhibitory effects. IC50 values were determined as 3.39, 6.38, 13.52, and 206 μM for CA I isozyme and 6.16, 20.29, 46, and 223 μM for CA II isozyme respectively.  相似文献   

12.
陶易凡  强俊  王辉  徐跑  马昕羽  赵文强 《水产学报》2016,40(11):1694-1704
研究了高pH胁迫对克氏原螯虾鳃、肝胰腺中酶活性的变化,以及对鳃、肝胰腺组织结构的影响。在得出96 h L C_(50)的基础上,设置对照(pH7.6)和实验(pH10.2)2个pH处理组,进行96 h高pH胁迫,于胁迫后0、2、8、24和96 h测定鳃Na~+-K~+-ATP酶、乳酸脱氢酶(lactate dehydrogenase,LDH)、延胡索酸还原酶(fumarate reductase,FRD)、肝胰腺超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)的活性以及丙二醛(malondialdehyde,MDA)的含量,并采集完整的鳃、肝胰腺做组织切片观察。结果发现,96 h LC50 pH值为10.194。高pH应激后,实验组鳃Na+-K+-ATP酶、LDH和FRD的活性呈上升趋势,pH胁迫8 h后与对照组差异显著(P0.05);随胁迫时间的延长,实验组肝胰腺MDA含量的变化趋势与LDH和FRD相似,CAT活性呈先上升后下降趋势,SOD活性起初变化不大,pH胁迫24 h后出现明显下降(P0.05)。鳃和肝胰腺的组织观察表明,随着pH胁迫时间的延长,鳃呼吸上皮细胞逐渐脱落,角质层受损、破裂,鳃叶受损程度逐渐加剧;肝胰腺小管基膜破损,小管内空泡增多、体积增大,肝细胞细胞数量减少。研究表明,高pH胁迫对克氏原螯虾代谢会产生影响,同时导致氧化应激,并会对鳃和肝胰腺的组织结构造成损伤,影响其生物学功能。  相似文献   

13.
The purpose of this work was to determine the tissue accumulation of lead (Pb) and its effects on osmoregulatory processes of the freshwater fish Prochilodus lineatus. Juvenile fish were exposed to Pb (from 1.7 to 0.7 mg of dissolved Pb L?1) for 6, 24 and 96 h and Pb accumulation was analyzed in the gills, liver, kidneys, blood cells and muscle. The following parameters were also analyzed: hematologic (hemoglobin content, hematocrit and number of red blood cells), metabolic (blood glucose), endocrine (blood cortisol), osmo ionic (plasma osmolality and Na+, K+, Cl? and Ca+2 concentrations), gill enzymes (Na+/K+-ATPase and carbonic anhydrase), chloride cell (CC) density and CC location in the gills. Pb accumulated in all the analyzed tissues, with the kidneys showing the highest concentration, followed by the gills and liver. The lowest Pb concentrations were found in blood cells and muscle. Pb promoted an increase in blood glucose after 6 and 24 h exposure. Gill Na+/K+-ATPase was inhibited after 24 h of exposure, but its activity was restored at 96 h, probably due to the increase in CC in gill lamellae. Plasma Na+ was reduced after 6 and 96 h, while K+ concentrations increased at all the experimental times. Fish exposed to Pb showed reduced plasma Ca+2 at all experimental periods. Hematologic parameters remained unchanged. Overall, this study demonstrated that Pb interferes in osmoregulatory processes of P. lineatus and the proliferation of CC in the gills is a response in order to reestablish adequate ion concentrations.  相似文献   

14.
An assay method based on thin layer chromatography to study the arachidonic acid (AA) metabolism in gill tissues was optimized and the effect of osmotically different incubation mediums on AA metabolism was evaluated. Rainbow trout gill tissues metabolize AA into PGE2 in highest concentration followed by PGD2, PGF2 and 6-keto-PGF1 (the stable metabolite of PGI2) among the prostanoids tested. Approximately 40% of PGE2 is synthesized within the first minute of incubation and is directly dependent on the substrate concentration (AA). As in mammalian tissues, PGE2 synthesis in fish gills is inhibited by the cyclooxygenase inhibitor indomethacin. PGE2 synthesis in gill homogenate and isolated gill cells incubated in trout Ringer was 0.45 and 1.9 ng/mg protein, respectively, and increased to 8.9 and 4.3 ng/mg protein, respectively, when incubated in KPO4 buffer, due to a ten-fold increase in the free AA. The hydroxy acid synthesis of the gill homogenate was higher (13%), and that of the isolated gill cells incubated in KPO4 buffer was lower (44%) compared to gill homogenate and cells incubated in trout Ringer. Gill homogenate incubated in 50 mM phosphate buffer with increasing sodium or potassium concentrations (up to 250 mM) exhibited a concentration-dependent increase in PGE2 synthesis (220% and 72%, respectively). Prolactin stimulated the PGE2 synthesis up to 30% while PGD2, PGF2 and 6-keto-PGF1 synthesis was not affected. This effect of prolactin was maximal when PGE2 synthesis was estimated 30 minutes after prolactin addition and diminished after two hours. These results suggest that rainbow trout gills possess the ability to metabolize AA through the cyclooxygenase and lipoxygenase pathways. PGE2 synthesis may be under the influence of ion balance and prolactin availability, indicating the probable involvement of AA metabolites in the regulation of ion balances across the gill membrane.  相似文献   

15.
The development and the application of a quantitative real‐time PCR for the detection of Tenacibaculum maritimum are described. A set of primers and probe was designed to amplify a 155‐bp fragment specific to the T. maritimum 16S rRNA gene. The test was shown to be very sensitive, able to detect as little as 4.8 DNA copies number μL?1. In addition, the assay was found to have a high degree of repeatability and reproducibility, with a linear dynamic range (R2 = 0.999) extending over 6 log10 dilutions and a high efficiency (100%). The assay was applied to DNA samples extracted from 48 formalin‐fixed paraffin‐embedded (FFPE) Atlantic salmon, Salmo salar, gill tissues showing varying degrees of gill pathology (scored 0–3) and from 26 jellyfish samples belonging to the species Phialella quadrata and Muggiaea atlantica. For each sample, the bacterial load was normalised against the level of the salmonid elongation factor alpha 1 (ELF) detected by a second real‐time PCR using previously published primers and probe. Tenacibaculum maritimum DNA was detected in 89% of the blocks with no signs of gill disease as well as in 95% of the blocks with mild‐to‐severe gill pathology. Association between bacterial load and gill pathology severity was investigated. T. maritimum DNA was detected at low level in four of the 26 jellyfish tested.  相似文献   

16.
Fish in a population of Pagothenia borchgrevinki in McMurdo Sound, Antarctica, are affected by a gill disease (X-cell disease) which causes tissue hyperplasia that results in a decreased gill surface area and an increased water/blood diffusion distance. P. borchgrevinki acquires 95% of its oxygen via the gills, but damage to the gills by X-cell disease did not affect this function. There was no compensatory shift to cutaneous respiration. X-cell disease reduced the ability for oxygen uptake at low ambient PO 2 and the decreased uptake was related to the extent of the disease. O 2 max was greatly reduced in X-cell affected fish and substantially reduced their aerobic potential. This effect may impair the ability of diseased fish to catch prey and avoid predators.  相似文献   

17.
We investigated the effects of open- and closed-system temperature changes on the O2 affinity of Atlantic bluefin tuna (Thunnus thynnus) blood using in vitro methods essentially identical to those previously employed on tropical tuna species. Bluefin tuna blood has a general O2 affinity (P 50 = 2.6–3.1 kPa or 19–23 mm Hg at 0.5% CO2) similar to that of skipjack tuna, yellowfin tuna, and kawakawa blood (P 50 = 2.8–3.1 kPa at 0.5% CO2) but significantly above that of bigeye tuna blood (P 50 = 1.6–2.0 kPa at 0.5% CO2). We therefore hypothesize that bluefin tuna are less tolerant of hypoxia than bigeye tuna. Further, we found the P 50 of bluefin tuna blood to be slightly reduced by a 10°C open-system temperature increase (e.g., from 4.83 kPa at 15°C to 3.95 kPa at 25°C) and to be completely unaffected by a 10°C closed-system temperature change. Bluefin tuna blood, therefore, had a significantly reduced Bohr effect when subjected to the inevitable changes in P CO 2 and plasma pH that accompany closed-system temperature shifts (0.04–0.09 Δlog P50ΔpH−1) compared with the effects of changes in plasma pH accomplished by changing P CO 2 alone (0.81–0.94 Δlog P50 Δ pH−1). This response is similar to that of skipjack tuna blood, but different from yellowfin or bigeye tuna blood. During closed-system temperature changes at oxygen levels above P 50, however, bluefin tuna blood showed a reversed temperature effect (i.e., P O 2 decreased in response to an increase in temperature). Unlike in other tuna species, temperature effects on O2 affinity of bluefin tuna whole blood were similar to those previously reported for hemoglobin solutions, suggesting that red cell-mediated ligand changes are not involved.  相似文献   

18.
A comprehensive acute toxicity trial was conducted using a static water system to study the toxic effect of ammonia on haematology and enzyme profiles of Cirrhinus mrigala H. The LC50 of total ammonia‐nitrogen (TAN) was 11.8 mg L?1 TAN (1.029 mg L?1 NH3‐N). The sub‐lethal test revealed that with increasing concentration of TAN, the total erythrocyte counts were reduced in lower concentrations (1–4 mg L?1 TAN) followed by higher levels in fish exposed to higher concentrations (8–16 mg L?1 TAN). In contrast, the total leucocyte counts were opposite. With increasing concentration of TAN, haemoglobin and serum protein content were reduced, whereas the blood glucose level increased. As the concentration of ammonia increased, there was a reduction in acetylecholinesterase activity in the brain and liver; alkaline phosphatase activity in the serum, brain and gill; and acid phosphatase (ACP) activity in the gill. The activity of lactate dehydrogenase in the gill, liver, kidney and brain increased with increased concentration of ammonia. In addition, activities of ACP in the serum and brain, alanine aminotransferase in the serum, brain and gill, and aspartate aminotransferase in the serum, brain and gill were increased.  相似文献   

19.
巨噬细胞移动抑制因子(macrophage migration inhibitory factor,MIF)是一类进化上古老的多功能细胞因子,广泛分布于细菌、植物和动物中。哺乳动物MIF兼具酶催化活性和趋化作用,在机体炎症反应中具有十分重要的作用。为探究MIF在鱼类免疫系统中的作用,本实验利用PCR技术克隆获得了日本鳗鲡MIF基因(AjMIF)。预测的AjMIF前体肽含MIF特征性的硫醇蛋白氧化还原酶活性基序Cys57-Ala-Leu-Cys60,以及异构酶活性相关的保守氨基酸残基,如Pro2和Cys81等。荧光定量结果显示,AjMIF在日本鳗鲡不同组织中均有表达,且在肝脏中表达量最高,其次为中肾和肠。脂多糖刺激8 h后,头肾、中肾和鳔中AjMIF表达量显著上调;PolyI:C刺激8 h后,鳃、皮肤和肠中AjMIF表达量显著上调。迟缓爱德华氏菌人工感染8 h后,肠和鳃中AjMIF表达量极显著上调;感染16 h后,鳃组织中MIF表达量显著升高;感染24 h后皮肤和鳃中MIF基因表达量显著上调。此外,本研究构建了AjMIF原核表达质粒,在获得重组蛋白的基础上研究了rAjMIF异构酶活性。结果显示,1 nmol重组蛋白在pH 6.2时异构酶活性为2.6 U,而在pH 8.0,酶活性为36.6 U。本研究结果为进一步解析MIF在鱼类免疫系统中的作用奠定了基础。  相似文献   

20.
为了探讨盐碱胁迫条件下鱼类渗透生理调节机制,以尼罗罗非鱼(Oreochromis niloticus)为实验材料, PCR扩增得到了Na+/3HCO-共转运子(NBCe1)基因cDNA部分序列,比较了单盐(盐度10、盐度15)、单碱(1.5 g/L、3 g/L NaHCO3)、盐碱混合(盐度10,碱度1.5 g/L;盐度15,碱度3 g/L)胁迫后不同时间(0 h、6 h、12 h、24 h、48 h、72 h、96 h)血清渗透压、离子浓度(Na+、K+、Cl–、Ca2+)以及鳃碳酸酐酶(CA)活性、CA与NBCe1基因mRNA表达变化。结果显示,不同胁迫条件下,血清渗透压、离子浓度、鳃组织 CA 酶活、CA 与 NBCe1基因 mRNA 表达变化均与胁迫强度呈正相关。随时间推移,血清渗透压、离子浓度呈现先上升后下降的变化趋势,单盐、盐碱混合组血清渗透压值较单碱组高。单盐、单碱、盐碱混合组中, NBCe1基因mRNA在鳃中均呈略微上调,但不显著(P>0.05)。单碱组和盐碱混合组鳃CA活性较单盐组高,低盐碱胁迫(盐度10,碱度1.5 g/L)下CA活性较晚达最高值;不同胁迫条件下, CA基因mRNA表达均表现上调,单碱、盐碱混合组更为显著(P<0.05),推测CA较NBCe1对体内3HCO-转运作用更为显著。研究结果为尼罗罗非鱼盐碱适应生理调节提供了基础资料。  相似文献   

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