Long-term potentiation and olfactory memory formation in the carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis> L.) olfactory bulb

Long-term potentiation of synaptic transmission is considered to be an elementary process underlying the cellular mechanism of memory formation. In the present study we aimed to examine whether or not the dendrodendritic mitral-to-granule cell synapses in the carp olfactory bulb show plastic changes after their repeated activation. It was found that: (1) the dendrodendritic mitral-to-granule cell synapses showed three types of plasticity after tetanic electrical stimulation applied to the olfactory tract—long-term potentiation (potentiation lasting >1 h), short-term potentiation (potentiation lasting <1 h) and post-tetanic potentiation (potentiation lasting <10 min); (2) Long-term potentiation was generally induced when both the dendrodendritic mitral-to-granule cell synapses and centrifugal fiber-to-granule cell synapses were repeatedly and simultaneously activated; (3) long-term enhancement (>1 h) of the odor-evoked bulbar response accompanied the electrically-induced LTP, and; (4) repeated olfactory stimulation enhanced dendrodendritic mitral-to-granule cell transmission. Based on these results, it was proposed that long-term potentiation (as well as olfactory memory) occurs at the dendrodendritic mitral-to-granule cell synapses after strong and long-lasting depolarization of granule cells, which follows repeated and simultaneous synaptic activation of both the peripheral and deep dendrites (or somata).     

Identification of keratins and analysis of their expression in carp and goldfish: comparison with the zebrafish and trout keratin catalog

With more than 50 genes in human, keratins make up a large gene family, but the evolutionary pressure leading to their diversity remains largely unclear. Nevertheless, this diversity offers a means to examine the evolutionary relationships among organisms that express keratins. Here, we report the analysis of keratins expressed in two cyprinid fishes, goldfish and carp, by two-dimensional polyacrylamide gel electrophoresis, complementary keratin blot binding assay, and immunoblotting. We further explore the expression of keratins by immunofluorescence microscopy. Comparison is made with the keratin expression and catalogs of zebrafish and rainbow trout. The keratins among these fishes exhibit a similar range of molecular weights and isoelectric points, with a similar overall pattern on two-dimensional gels. In addition, immunofluorescence microscopy studies of goldfish and carp tissues have revealed the expression of keratins in both epithelial and mesenchymally derived tissues, as reported previously for zebrafish and trout. We conclude that keratin expression is qualitatively similar among these fishes, with goldfish and carp patterns being more similar to each other than to zebrafish, and the cyprinid fishes being more similar to each other than to the salmonid trout. Because of the detected similarity of keratin expression among the cyprinid fishes, we propose that, for certain experiments, they are interchangeable. Although the zebrafish distinguishes itself as being a developmental and genetic/genomic model organism, we have found that the goldfish, in particular, is a more suitable model for both biochemical and histological studies of the cytoskeleton, especially since goldfish cytoskeletal preparations seem to be more resistant to degradation than those from carp or zebrafish. This work was supported by grants to J.M. from the Stiftung Rheinland Pfalz für Innovation (836-386261/138) and the Deutsche Forschungsgemeinschaft (Ma 843/5-1) and a grant to D.G. from the National Science Foundation (INT-0078261).     

Tissue- and stressor-specific differential expression of two hsc70 genes in carp

Two genes expressing 70 kDa heat shock proteins were identified in Cyprinus carpio. The sequence similarities and the intron-interrupted structure of the coding regions indicate that carp Hsc70-1 and Hsc70-2 belong to the Hsp70 cognate subfamily. The expressions of the two hsc70 genes were followed by semi-quantitative RT-PCR. Both genes are expressed under unstressed conditions in a characteristic tissue-specific manner. Inducibility of the response to elevated temperature, cold shock, and Cd treatment was investigated in the liver and muscle, in whole-animal experiments. Both genes were insensitive to or only weakly induced by the stressors, with two exceptions: Cd treatment resulted in an 11-13-fold enhanced induction of hsc70-1 in the liver and cold shock enhanced induction of hsc70-2 in the muscle by 7.5-10-fold.     

Effects of estradiol, progesterone and testosterone on the function of carp, Cyprinus carpio, phagocytes in vitro

The modulation of phagocytic cells by beta-estradiol, 11-ketotestosterone and progesterone was analyzed in common carp Cyprinus carpio. Carp kidney leukocytes were cultured in RPMI 1640 medium containing 0.1, 1, 10, 100 or 1000 nM concentration of each hormone. The production of superoxide anion, nitric oxide (NO) and phagocytosis were measured in vitro. Similar concentrations of cortisol were used as control. Phagocytic activities of carp macrophages was suppressed by treatment with beta-estradiol, progesterone and 11-ketotestosterone. The production of NO in carp macrophages was suppressed by progesterone and 11-ketotestosterone. However, carp macrophages incubated with beta-estradiol, progesterone and 11-ketotestosterone did not show any difference in the production of superoxide anion in comparison with control macrophages in the absence of hormones. Carp macrophages treated with cortisol suppressed phagocytosis and the production of nitric oxide and superoxide anion.     

饥饿对草鱼非特异免疫水平的影响

研究了长期饥饿对草鱼(Ctenopharyngodon idellus)非特异性免疫水平的影响。实验选取平均体质量(31.86±1.47)g的草鱼,随机分为2个实验组(对照组和饥饿组),每组3个平行,饥饿处理15、30、45和60 d,测定饥饿对草鱼头肾和脾中自然杀伤(NK)细胞的杀伤活性、血清和肝胰脏中溶菌酶活性、血清中碱性磷酸酶活性的影响。结果表明:受饥饿胁迫的影响,草鱼自然杀伤性细胞在脾和头肾中的杀伤活性显著低于对照组(P0.05)且不随着饥饿时间的延长发生显著性变化;随着饥饿时间的延长,血清和肝胰脏中溶菌酶呈现先升高后降低的趋势,血清碱性磷酸酶在饥饿15、45、60 d时显著低于对照组;饥饿组的碱性磷酸酶活性在饥饿30 d以后,维持恒定。由此可见,长时间的饥饿胁迫降低了草鱼的免疫水平。相比较而言,自然杀伤细胞的杀伤活性在反映鱼类免疫状况时比溶菌酶和碱性磷酸酶可能更为灵敏。     

高效降解蛋白枯草芽孢杆菌的筛选及促建鲤生长的研究

【目的】从建鲤肠道分离并优选出了一株对蛋白具有强效降解力的菌株,探究其临床生产效果。【方法】使用牛奶平板进行筛选,经常规细菌学鉴定和16S rDNA序列分析确定A7菌株为枯草芽孢杆菌,通过临床饲喂试验探究其对建鲤促生长作用。【结果】A7菌株在牛奶平板上的水解圈直径可达27.5 mm,其最佳固体发酵条件为温度28°C、接种量5%(1.2×109 CFU/mL)、料水比1.0:1.2和发酵时间72 h。临床饲喂试验结果表明,饵料中添加0.5%、1.0%和1.5%的A7株菌粉均能促建鲤生长。其中,添加量为1.0%的试验组,鱼体增重率和蛋白利用率最高,饵料系数最低,与产品对照组和空白对照组相比,均达到了显著性差异(P0.05)。此外,随A7株菌粉添菌量的增加,各试验组肝胰脏和肠道的蛋白酶及淀粉酶活力出现先增大后减小趋势,与产品对照组和空白对照组相比,添加1.0%的试验组增幅最大(P0.05)。研究发现,试验组鱼肌肉中粗蛋白和粗脂肪含量较空白对照组也有明显的增减趋势(P0.05)。【结论】饵料中添加A7株菌粉,可有效促进鱼的生长,降低饵料系数,提高肝胰脏和肠道的蛋白酶及淀粉酶活力,并提高鱼肌肉中的蛋白含量和降低脂肪含量。     

Toxic Effects of Paraquat on Cytokine Expression in Common Carp,Cyprinus carpio L.

In this study, the acute toxicity of paraquat (PQ) in common carp was determined. Then, the contents and mRNA levels of the cytokines interleukin‐1β (IL‐1β), interferon‐γ (IFN‐γ), and tumor necrosis factor‐α (TNF‐α) were evaluated following subacute exposure to PQ. The results show that the LC₅₀ of PQ for common carp at 72 and 96 h was 15.962 and 15.106 mg/L, respectively. Moreover, after 7 days of subacute PQ exposure, the IL‐1β content in the fish liver and kidney increased, although it decreased in spleen. However, changes in the IFN‐γ content showed an irregular trend. The TNF‐α content increased in the liver and spleen but decreased in the kidney. Additionally, PQ exposure also induced alterations in the mRNA levels of IL‐1β, IFN‐γ, and TNF‐α. These results suggest that PQ exposure may result in suppression or excessive activation of the immune system in treated fish and lead to immune dysfunction and reduced immunity.     

小浪底水库运行对黄河鲤鱼栖息地的影响

通过历史文献和实地生态调查,了解黄河鲤鱼生态习性及与径流组分响应关系,在此基础上,通过分析水库对径流组分影响,建立栖息地模拟模型,研究小浪底水库运行对黄河鲤鱼生存繁衍的影响。研究表明:(1)径流的流量组分与黄河鲤鱼的生态习性有密切的相关关系,小浪底水库的运行显著改变了流量脉冲、小洪水及大洪水,流量脉冲消失或减少使得黄河鲤鱼产卵缺乏足够的产卵栖息地;小洪水减少使黄河鲤鱼的食物来源和栖息地减少;漫滩洪水减少和消失使黄河鲤鱼失去从河滩地获得食物和栖息地机会。(2)通过建立River2D模型,得到了不同流量下黄河鲤鱼在不同生命阶段栖息地面积的变化情况,研究表明,建库后大于1400m3/s流量的显著减少,影响了黄河鲤鱼的产卵;建库后花园口低限流量变化不明显,建库对成鱼和幼鱼生存的影响不大。     

鲤TRAP分子标记反应体系的建立与优化

针对鲤(Cyprinus carpio)这一主要水产养殖品种设计了靶位区域扩增多态性(target region amplified polymorphism,TRAP)分子标记的反应体系,对影响TRAP反应体系的各参数,包括Mg2+、dNTPs、TaqDNA聚合酶、模板DNA和引物浓度进行了优化,建立了适合鲤的、稳定、可重复的TRAP-PCR反应体系。在15μlPCR反应体系中,Mg2+浓度为1.5mmol/L、dNTPs浓度为0.35mmol/L、两个随机引物浓度均为3pmol/L、固定引物浓度为10pmol/L、含DNA模板60ng、TaqDNA聚合酶1.0U。鲤的TRAP反应程序为:94℃4min,1个循环;94℃45s,35℃45s,72℃1min,5个循环;94℃45s,53℃45s,72℃1min,35个循环;72℃10min,1个循环。这一优化体系的建立为今后进行鲤群体遗传多样性、种质鉴定、遗传连锁图谱及亲缘关系分析等方面的研究提供了新的分子标记。