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1.
In this study, two isoforms slc34a2 genes (type IIb sodium-dependent phosphate cotransporter), slc34a2a2 and slc34a2b, were cloned from intestine and kidney of yellow catfish (Pelteobagrus fulvidraco), with rapid amplification of cDNA ends. The structure differences and the regulation effects of dietary VD3 under low phosphorus were compared among three isoforms of slc34a2 in yellow catfish. The predicted Slc34a2a2 and Slc34a2b proteins match 65 % and 53.8 % sequence identity, with Slc34a2a1, respectively. The membrane-spanning domains were different among these three isoforms. Intestinal Slc34a2a1 and Slc34a2a2 proteins had eight and eleven transmembrane domains, while renal Slc34a2b protein had nine. The tissue distribution study showed that same as slc34a2a1, slc34a2a2 mRNA was mainly distributed in intestine and slc34a2b mRNA in kidney. The effect of vitamin D3 (VD3) level on slc34a2 subfamily expression under low-phosphate conditions, induced by the addition of 0 (VD0), 324 (VD1), 1243 (VD2), 3621 (VD3), 8040 (VD4), or 22700 (VD5) IU VD3/kg feed, was assessed by qPCR. The dose-responsive expression of intestinal slc34a2a2 and high expression of intestinal slc34a2a2 in VD5 together with peak expression of kidney slc34a2b in VD3 coincided with the accumulation of body phosphate content. These data suggested that appropriate level of dietary VD3 up-regulated slc34a2a1, slc34a2a2, and slc34a2b mRNA levels, which increased phosphate retention. In conclusion, the current study provided another possible approach to improve dietary phosphate utilization by adding appropriate level of VD3 to a low-phosphate diet to regulate intestinal and renal slc34a2 gene expression and thus minimize the excretion of phosphorus in yellow catfish.  相似文献   

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卓梅琴  杨水波  凌仕诚  罗智 《水产学报》2019,43(10):2186-2196
为了探究饲料不同脂肪水平对黄颡鱼卵巢脂肪代谢潜在的影响,本研究设计了活体与离体两个实验。活体实验中,分别投喂3组不同脂肪水平的饲料(脂肪含量分别为6.98%、11.34%和15.41%)8周。离体实验中,分离原代黄颡鱼卵母细胞,采用(0、0.2和0.5 mmol/L)3组不同脂肪酸浓度孵育48 h。活体实验结果显示:与6.98%和15.41%脂肪水平组相比,11.34%脂肪水平显著增加黄颡鱼卵巢甘油三酯水平(TG),并上调FAS、G6PD、6PGD和ME的酶活性水平,以及LPL和CD36基因表达水平。与6.98%和11.34%脂肪水平组相比,15.41%脂肪水平组显著升高黄颡鱼的性腺指数(GSI),并上调CPTIA和DNMT3b的基因表达水平,以及PI3KCa启动子-64和-52 CpG位点的甲基化水平,而显著降低PI3KCa的基因表达水平。体外细胞实验显示:与对照组(0)相比,0.5 mmol/L脂肪酸孵育显著增加卵母细胞TG含量,并上调FAS、G6PD和ME酶活水平,以及G6PD和PI3KCa的基因表达水平。同时,与对照组相比,脂肪酸孵育组显著降低CPTIA、ACCb、LPL、CD36、DNMT1以及DNMT3b基因的表达水平。然而,脂肪酸孵育对卵母细胞PI3KCa的启动子甲基化水平没有影响。研究表明,饲料不同脂肪水平影响卵巢TG的合成,可能主要是通过脂肪转运相关基因,并且高脂肪很可能是通过影响黄颡鱼卵巢PI3KCa启动子甲基化水平来影响PI3KCa的表达。而离体条件下,脂肪酸促进卵母细胞TG的合成很可能是通过升高脂肪合成相关基因、降低脂肪分解和转运相关基因来实现,但脂肪酸孵育不通过影响黄颡鱼卵母细胞PI3KCa甲基化水平来影响PI3KCa基因表达。  相似文献   

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In fish, spermatogenesis and somatic growth are mainly regulated by hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-somatic (HPS) axes, respectively. Xenoestrogens have been reported to impair spermatogenesis in some fishes, and arrest somatic growth in some others, whereas, whether xenoestrogens are capable of disrupting spermatogenesis and somatic growth simultaneously in fish that exhibits sexual dimorphic growth is little known, and the underlying mechanisms remain poorly understood. In this study, male juveniles of yellow catfish (Pelteobagrus fulvidraco), which exhibits a sexual dimorphic growth that favors males, were exposed to diethylstilbestrol (DES) for 28 days. After exposure, DES significantly disrupted the spermatogenesis (decreased gonadal-somatic index (GSI) and germ cell number) and arrested the somatic growth (declined body weight) of the catfish juveniles. Gene expression and plasma steroid analyses demonstrated the suppressed mRNA levels of genes in HPG axis (gnrh-II, fshβ, and lhβ in the brain and dmrt1, sf1, fshr, cyp17a1, cyp19a1a, and cyp11b2 in the testis) and decreased 17β-estrodial (E2) and 11-ketotestosterone (11-KT) levels in plasma. Further analysis revealed the arrested germ cell proliferation (cyclin d1), meiosis (dmc1, sycp3), and enhanced apoptosis (decreased bcl-2 and elevated bax/bcl-2 ratio) in the testis. Besides, DES also suppressed the mRNA levels of genes in HPS axis (ghrh, gh, and prl in the brain and ghr, igf1, igf2a, and igf2b in the liver). The suppressed HPG and HPS axes were thus supposed to disturb spermatogenesis and arrest somatic growth in yellow catfish. The present study greatly extended our understanding on the mechanisms underlying the toxicity of DES on spermatogenesis and somatic growth of fish.  相似文献   

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This study was designed in vitro to investigate the effects of l-carnitine against H2O2-induced oxidative stress in a grass carp (Ctenopharyngodon idellus) ovary cell line (GCO). GCO cells were pre-treated with different concentrations of l-carnitine, followed by incubation with 2.5 mM H2O2 for 1 h to induce oxidative damage. The results indicated that adding l-carnitine at concentrations of 0.01–1 mM into the medium for 12 h significantly increased cell viability. Pre-treatment with l-carnitine at concentrations of 0.1–5 mM for 12 h significantly inhibited 2.5 mM H2O2-induced cell viability loss. The significant decreases in the level of reactive oxygen species and cell apoptosis were observed in 0.5 mM l-carnitine group compared to the H2O2 group. Malondialdehyde values of all of the l-carnitine groups were significantly lower than those of the H2O2 group, while total glutathione levels of all of the l-carnitine groups were significantly higher than of the H2O2 group. The activity of antioxidant enzymes, such as total superoxide dismutase (0.1 and 0.5 mM l-carnitine), catalase (0.5 mM l-carnitine) and γ-glutamyl cysteine synthetase (0.5 and 1 mM l-carnitine), was significantly increased. In addition, pre-treatment of l-carnitine in GCO cells exposed to 2.5 mM H2O2 significantly increased the mRNA expression of copper, zinc superoxide dismutase, catalase (0.5 mM l-carnitine), glutamate cysteine ligase catalytic subunit (0.1–1 mM) and glutathione peroxidase (0.1 mM l-carnitine). In conclusion, l-carnitine promotes GCO cell growth and improves antioxidant function, it plays a protective role against oxidative stress induced by H2O2 in GCO cells, and the appropriate supplemental amount of l-carnitine is 0.1–1 mM.  相似文献   

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分别给凡纳滨对虾(Litopenaeus vannamei)注射生理盐水、3×106 CFU/mL(低浓度组)和9×106 CFU/mL(高浓度组)溶藻弧菌(Vibrio alginolyticus)菌液, 采用荧光定量PCR技术, 检测不同处理后凡纳滨对虾鳃组织中Toll受体、IMD和溶菌酶基因表达量随时间的变化。结果表明, 处理42 h内, 注射生理盐水组对虾的Toll受体和IMD mRNA表达量无显著变化, 溶菌酶mRNA表达量在注射36 h后显著升高。急性感染溶藻弧菌后, 凡纳滨对虾鳃组织中Toll受体、IMD和溶菌酶mRNA的表达量峰值分别出现在感染后24、42和36 h; 溶藻弧菌的感染剂量不影响上述基因表达峰值的出现时间, 但显著影响上述基因的表达峰值(P<0.05), 各基因表达量峰值由大到小均依次为高浓度组、低浓度组、生理盐水组。急性感染初期, 对虾鳃组织中Toll受体mRNA表达量呈现显著下调, 而IMD和溶菌酶mRNA表达量在感染初期不存在显著下调现象。与感染前各基因的表达量相比, 高浓度溶藻弧菌感染组Toll受体mRNA表达量在2 h时显著下调, 低浓度溶藻弧菌感染组Toll受体mRNA表达量在3 h显著下调(P<0.05); 高浓度组IMD和溶菌酶mRNA表达量分别在36 h和12 h时开始有显著上调, 而低浓度组IMD和溶菌酶mRNA表达量则分别在42 h和24 h才有显著上调(P<0.05)。表明溶藻弧菌感染对凡纳滨对虾鳃组织中Toll受体、IMD和溶菌酶mRNA表达量有显著影响, 各基因的表达量与感染进程及溶藻弧菌剂量存在一定的相关性。

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The aim of this study is to explore the effect of Aeromonas hydrophila on the intestinal mucosal barrier structure and intestinal permeability in grass carp (Ctenopharyngodon idella). Histopathological examinations showed that A. hydrophila induced severe intestinal lesions, including inflammatory cell infiltration and intestinal villus fusion and swelling. Messenger RNA (mRNA) expression of the inflammatory cytokines TNF-α, IL-1β, IL-8, IL-10 and MyD88 was significantly increased after infection with A. hydrophila. The permeability of intestinal mucosa was determined using Evans blue (EB) and d-lactic acid. The results indicated that the levels of EB and serum d-lactic acid were significantly increased after infection with A. hydrophila (p < 0.05). Our results also indicated that the intestinal mucosal barrier injury induced by A. hydrophila infection was closely associated with the expression of the tight junction (TJ) protein zonula occludens-1 (ZO-1), occludin, claudin b and claudin c as well as the activity of Na+, K+-ATPase and Ca2+, Mg2+-ATPase. Lower mRNA levels of occludin and lower Na+, K+-ATPase and Ca2+, Mg2+-ATPase activity in the intestines were observed after challenge. ZO-1 and claudin c were significantly increased 24 h after infection with A. hydrophila. The most interesting finding was that claudin b also significantly increased 24 h after challenge and then decreased to lower levels at 72, 120 and 168 h post-infection compared to the PBS-treated control group. The results demonstrated that grass carp infection with A. hydrophila induced intestinal inflammation and impaired the structure and function of the intestinal mucosal barrier.  相似文献   

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The viability using Lippia alba essential oil as an anesthetic for fish was studied, particularly with respect to physiological effects during recovery. Anesthesia of silver catfish (Rhamdia quelen) using 100 and 300 μL L?1 of two different chemotypes of L. alba essential oil (citral EO-C and linalool EO-L) prevented the increase of plasma cortisol levels caused by handling, but did not avoid alterations in energetic metabolism. Silver catfish did not have increased the levels of thiobarbituric acid reactive species in the kidney and liver during recovery after anesthesia with either EO, avoiding lipid damage. On the other hand, fish anesthetized with EO-C showed higher protein carbonylation levels, superoxide dismutase, catalase, and glutathione S-transferase activities and non-protein thiol group levels in both tissues compared to controls. Our results suggest that both oils show antioxidant capacity, but anesthesia with EO-L does not cause damage to lipids or proteins, only temporary changes, typical of physiological adjustments during recovery from anesthesia. Therefore, EO-L is an effective anesthetic for silver catfish with fewer side effects than EO-C.  相似文献   

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Trypsin from the pyloric ceca of orange-spotted grouper, Epinephelus coioides, was purified by fractionation with ammonium sulfate, ionic exchange, and affinity chromatography. The protein was purified 161.85-fold with a yield of 4%. Purified trypsin had an apparent molecular weight of 24 kDa according to an SDS-PAGE analysis. Optimal profiles of temperature and pH of the enzyme were 50°C and 8–10, respectively, using Nα-benzoyl-l-arginine ethyl ester as the substrate. The results of thermal and pH stability assays showed that the enzyme was stable at temperatures of up to 50°C and in the pH range of 6–8. Trypsin activity decreased with an increasing NaCl concentration (0–0.6 M). The activity of purified trypsin was effectively inhibited by a soybean trypsin inhibitor and N-p-tosyl-l-lysine chloromethyl ketone, and was slightly inhibited by iodoacetic acid, ethylenediaminetetraacetic acid, 1-(l-trans-epoxysuccinyl-leucylamino)-4-guanidinobutane, and pepstatin A. Protein identification of the purified protease showed that the sequences of two peptides, LGEHNI and NLDNDIML, were highly homologous to other fish trypsins. The measurement of trypsin activity in different tissues showed that the highest activity was detected in pyloric ceca, followed by anterior intestine, middle intestine, hind intestine and spleen, but very low activities were found in other tissues. An inverse relationship between the trypsin activity in four tissues of pyloric ceca, anterior intestine, middle intestine and hind intestine and fish body weight as a result of increased pepsin in stomach indicated grouper growth status was increased.  相似文献   

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Increased understanding of the factors that influence the frequency of purchase of catfish (Ictalurus punctatus) by U.S. households would provide guidance for catfish marketing programs. A household survey was conducted to analyze consumer preferences and consumption trends of U.S. farm-raised catfish in Birmingham, Memphis, Chicago, Jackson (MS), New Orleans, Baton Rouge, Little Rock, Oklahoma City, Dallas, Houston, and San Antonio. An ordered probit model was developed to examine the variables influencing frequency of catfish purchase. Household respondents in all cities except Jackson, New Orleans, Oklahoma City, and San Antonio were found to be more frequent buyers of catfish products. Respondents who preferred fresh catfish had a greater likelihood of frequent catfish purchase while buyers of frozen catfish were less likely to purchase catfish frequently. Method of preparation and serving had no influence on catfish purchase frequency. Buyers purchasing from supermarket outlets had a higher probability of being more frequent buyers of catfish products than those who purchase from other market outlets. Product origin labels and vacuum-sealed packaging influenced the frequency of catfish purchase. Caucasians and African Americans were found to be more frequent buyers of catfish products while Hispanics were found to be significantly less frequent buyers of catfish products. Married couples had a greater likelihood of purchasing catfish more frequently than unmarried couples. Age of the respondents as well as number of household members had no significant effect on frequency of catfish purchase. The results from this study support the importance of country of origin labeling, supplying high-quality fresh products, and alternative packaging to enhance sales of U.S. farm-raised catfish in supermarkets.  相似文献   

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Consumer uncertainty of irradiated food products has slowed implementation of food irradiation, even though it has been proven as a safe and effective technology. For acceptance, irradiated products should not be distinguishable from alternatively processed products. The present research was designed to determine if X-ray irradiation treatment results in changes in selected quality parameters (color, texture, and oxidation) of fresh aquacultured channel catfish fillets. Fillets (Ictalurus punctatus) were treated to 0, 0.5, 1.0, and 1.5 kGy using an X-ray irradiator and stored at 3°C for 17 days. Periodically during storage, samples were removed and instrumentally measured for color, texture, and oxidation (thiobarbituric acid reactive substances). Color, texture, and oxidation did not change (p > 0.05) over time or with irradiation dose. Results indicated that low-dose X-ray treated raw catfish fillets were not distinguishable from untreated controls.  相似文献   

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草鱼天然抗性相关巨噬蛋白基因的表达特征与蛋白表达   总被引：1，自引：0，他引：1  
为探讨Nramp基因在草鱼(Ctenopharyngodon idellus)免疫应答中的作用,采用实时荧光定量PCR技术,对比研究了Nramp基因在草鱼不同发育阶段、不同组织及嗜水气单胞菌(Aeromonas hydrophila)攻毒感染后4个组织不同时间的差异表达,并利用原核表达技术对草鱼Nramp基因ORF区642 bp的目的片段进行蛋白表达,获得40 k D的融合蛋白。实时荧光定量PCR分析结果表明,Nramp在草鱼胚胎发育过程中的表达量随着发育时间的增加而逐渐增强,在幼鱼期的表达量达到最大。成年健康草鱼不同组织中的表达量差异显著(P0.05),在肝中的表达量最高,其次是在脾、头肾、肠中的表达量较高,而在眼和鳔中的表达量最低。草鱼感染嗜水气单胞菌后,在头肾、肝、脾、肠中Nramp的表达量都显著上升(P0.05),在头肾中感染12 h后显著上升,48 h达到最大,在72 h和96 h时又显著下调,在7 d时表达量继续下调而逐渐回归到初始水平;在肝中Nramp基因的表达量在4 h时出现下调,在12 h又显著上调,随后在24 h出现下调,在48 h又上调,72 h达到最大并保持较高水平到7 d;在肠中m RNA表达量在12 h显著上调,48 h达到最大,在72 h和96 h显著下调,在7 d时表达量基本回归到初始水平;在脾中m RNA表达量在4 h开始上升,12 h达到最大,在24 h和48 h表达水平显著下调,在7 d时表达量回归到初始水平。草鱼感染致病菌可引起免疫相关组织中Nramp的表达量上升,说明Nramp在硬骨鱼类的天然免疫反应过程中发挥着重要作用。  相似文献   

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In coastal New England, growing oysters is a long-established practice that has exhibited a renaissance over the past few decades (Lapointe, Northeast region ocean council white paper: Overview of the aquaculture sector in New England, 2013). This industry generates millions in annual revenue, significantly boosting the economies of many coastal communities (Augusto &; Holmes, 2015 Augusto, K. &; Holmes, G. (2015). Massachusetts shellfish aquaculture economic impact study. Woods Hole, MA. Retrieved from http://web.whoi.edu/seagrant/wp-content/uploads/sites/24/2015/01/MA-Aquaculture-Economic-Impact-Study-2015.pdf [Google Scholar]). However, oyster aquaculture has received relatively little attention from the field of economics. To our knowledge, this study represents the first evaluation of productive efficiency among oyster producers in the United States and the first comparison of oyster production methods used in this country. Our findings indicate significant potential to increase productivity by reducing inefficiency in oyster production. However, industry-wide production efficiency has been increasing between 2013 and 2015. Further analysis revealed several factors that significantly influence inefficiency in oyster production, including a grower’s education level, location and farm diversification. This study provides insights into inefficiency in oyster production, enabling governance bodies and outreach specialists to make more informed decisions regarding this industry.  相似文献   

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Thai koi is one of the high commercially valued farm fishes which have expanded tremendously in the northern part of Bangladesh. However, despite its impressive growth in the initial years, output of the industry is highly volatile across different years and farms. This research, following the Just and Pope framework, has made use of Kumbhakar’s (2002 Kumbhakar, S.C. (2002) Specification and estimation of production risk, risk preferences, and technical efficiency. American Journal of Agricultural Economics, 84, 8–22.[Crossref], [Web of Science ®] , [Google Scholar]) extended stochastic frontier model (SFM) to estimate production risk and technical efficiency (TE) in Thai koi farming. Results show that feed is the most important input significantly influencing production. Zeolite and pesticide appear to be risk-reducing, while fingerlings, labor, feed and salt turn out to be risk-increasing inputs. The inefficiency model indicates that labor and pond area significantly reduce the technical inefficiency. Feed, fingerling and lime also act as TE-improving factors. Education of farmers improves TE, while experience, training and frequency of water change do not impact the TE. The mean TE scores are 0.73 and 0.96 for the flexible risk estimate and conventional SFM estimates, respectively. TE values appear to become exaggerated when production risk is excluded from the model. SFM recognizes that risk is involved in Thai koi farming that causes lower TE.  相似文献   

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Spermatogenesis represents one of the most complicated morphological transformation procedures. During this process, the assembly and maintenance of the flagella and intracellular transport of membrane-bound organelles required KIF3A and KIF3B. Our main goal was to test KIF3A and KIF3B location during spermatogenesis of Boleophthalmus pectinirostris. We cloned complete cDNA of KIF3A/3B from the testis of B. pectinirostris by PCR and rapid amplification of cDNA ends (RACE). The predicted secondary and tertiary structures of B. pectinirostris KIF3A/3B contained three domains: (a) the head region, (b) the stalk region, and (c) the tail region. Real-time quantitative PCR (qPCR) results revealed that KIF3A and KIF3B mRNA were presented in all the tissues examined, with the highest expression seen in the testis. In situ hybridization (ISH) showed that KIF3A and KIF3B were distributed in the periphery of the nuclear in the spermatocyte and the early spermatid. In the late spermatid and mature sperm, the KIF3A and KIF3B mRNA were gradually gathered to one side where the flagella formed. Immunofluorescence (IF) showed that KIF3A, tubulin, and mitochondria were co-localized in different stages during spermiogenesis in B. pectinirostris. The temporal and spatial expression dynamics of KIF3A/3B indicate that KIF3A and KIF3B might be involved in flagellar assembly and maintenance at the mRNA and protein levels. Moreover, these proteins may transport the mitochondria resulting in flagellum formation in B. pectinirostris.  相似文献   

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