Changes in plasma glucagon and insulin associated with fasting in sea bass (Dicentrarchus labrax)

Juvenile sea bass (Dicentrarchus labrax) were fasted for 22 days and changes in plasma insulin, glucagon and glucose levels, as well as glycogen and protein content in liver and muscle were analyzed. Glucagon increased initially on the 4th day of fasting. The glucagon/insulin ratio (G/I) increased from a value of 0.11±0.02 (24h of fasting) to 0.21±0.05 (4th day of fasting). Thereafter, both glucagon and insulin levels decreased and remained at low concentrations until the 22nd day of fasting. Plasma glucose levels fell at the beginning of fasting, stabilized between the 4th and 8th day, and gradually declined during the rest of the experiment. There was a body weight loss of 15% and a significant decrease in both the hepatosomatic index and mesenteric fat. The decrease in the percentage of muscle proteins was not significant, while liver glycogen content showed a sharp decline.     

罗氏沼虾肌肉白浊病发病池和未发病池水质状况比较

对罗氏沼虾肌肉白浊病发病与未发病育苗池以及发病与未发病大棚培育土池 ,进行了 pH值、氨氮、亚硝酸盐氮、硝酸盐氮、化学耗氧量和可溶性磷酸盐检测 ,结果显示 ,发病池与未发病池之间这些水质因子均无显著差异 (P(0 .0 5 )。对罗氏沼虾苗有较大毒性的非离子态氨氮和亚硝酸盐氮含量都在安全浓度范围内 :淡化前 ,发病育苗池中两者的平均值分别为 0 .173mg/L、0 .0 83mg/L ,未发病育苗池中分别为 0 .2 0 1mg/L、0 .10 3mg/L ;淡化后 ,发病育苗池中两者的平均值分别为 0 .0 33mg/L、0 .0 4 0mg/L ,未发病育苗池中分别为 0 .0 2 7mg/L、0 .0 39mg/L ;在发病大棚培育土池中 ,两者的平均值分别为 0 .114mg/L、0 .0 6 1mg/L ,在未发病大棚培育土池中分别为 0 .112mg/L、0 .0 76mg/L。检测结果表明 :罗氏沼虾肌肉白浊病与所测的这些水质因子无关。     

Haematological and biochemical responses of freshwater teleost fish Cyprinus carpio (Actinopterygii: Cypriniformes) during acute and chronic sublethal exposure to lindane

The impact of acute and sublethal toxicity of a synthetic organochlorine pesticide lindane on some haematological and biochemical parameters of a freshwater fish Cyprinus carpio was estimated. The median lethal concentration of lindane for 24 h was 0.38 ppm. During acute treatment (24 h), hemoglobin (Hb), hematocrit (Hct) and erythrocyte (RBC) values were decreased, whereas leucocyte (WBC) count increased in the pesticide treated fish. The hematological indices like mean cellular volume (MCV), mean cellular hemoglobin (MCH) and mean cellular hemoglobin concentration (MCHC) were decreased when compared to control group. Biochemical profiles like plasma glucose and protein levels were increased in lindane exposed fish showing a percent increase of 50.36 and 3.98 at the end of 24 h treatment. However, glycogen content in liver and muscle were decreased showing a percent decrease of 21.70 and 1.74. In sublethal treatment (1/10th of LC50 24 h value, 0.038 ppm), RBC count was decreased whereas WBC count increased in the pesticide treated fish throughout the study period (25 days). Hb and Hct values were decreased up to 10th day and after that recovered showing a significant increase in the rest of the study period. Similarly, a biphasic response was observed in the value of MCV, MCH and MCHC. Plasma glucose level was significantly increased while plasma protein level decreased throughout the study period. Further, glycogen level in muscle and liver were showed a mixed trend. In the present study, the pesticide lindane caused alterations on haematological and biochemical parameters of C. carpio and these alterations can be used as non specific biomarkers in pesticide contaminated aquatic ecosystem.     

智能肌肉嫩度计的研制

利用计算机技术和传感器技术对机械式肌肉嫩度计进行了改进设计。用蜡笔及马铃薯对仪器的准确性进行了测试，并用猪肉和鸡肉对仪器的可靠性进行检验。测试结果表明，该仪器测量精度较高，可靠性好。     

红宝两系制种与杂交利用

本试验以红宝父母代鸡为材料，连续进行４个世代的自繁与杂交，结果表明，父母代母系母鸡３００日龄产蛋量没有发生明显变化（６０枚左右）；商品代鸡８周龄体重比引种时增加７．２％￣１１．３％；红宝与苏北土种鸡杂交改良，杂种７０日龄体重比苏北土种鸡增加１０３．７４％；此外，对红宝苏北土种鸡以及杂种ＡＫＰ、ＳＧＰＴ、ＣＰＫ与生产能力关系分析，发现红宝与土种鸡杂交的杂种鸡ＡＫＰ活性比土种鸡减少９１．２６个单位，与     

60～90日龄腾冲雪鸡肌纤维特性研究

使用组织学方法,对16只60和90日龄的腾冲雪鸡的胸肌纤维直径、纤维密度进行了测定,并与体型指标和活体重进行了表型相关分析.结果表明同日龄公母鸡的肌纤维直径无显著差异(P＞0.05),不同日龄的肌纤维直径差异极显著(P＜0.01),60日龄时公母鸡的纤维直径分别为31.40±7.36 μm和32.36±8.11 μm,90日龄时公母鸡的纤维直径分别为38.68±9.42 μm和37.67±9.14 μm;因而90日龄以前上市的肉用仔鸡公母性别间肉的细嫩度差异较小.不同日龄纤维直径差异极显著,且年龄越大,肌纤维直径变大,表明肌肉细嫩度越差.随着日龄的增长,肌纤维同步增长,但肌纤维生长变异不大(P＞0.05).肌纤维直径与鸡的日龄和胸宽有显著的表型相关关系(P＜0.01),与龙骨长和活重有显著相关关系(P＜0.05),因而这为肌纤维细度的表型选择提供了一定的方便.不同日龄和性别间单位面积内的肌纤维密度没有显著差异(P＞0.05),但表现出随年龄增加密度加大和公鸡的密度大于母鸡的密度的规律, 60和90日龄时公母鸡纤维密度分别为1 165.12±58.86根/mm2和1 111.11±192.45根/mm2,1 231.48±242.63根/mm2和1 194.45±134.72根/mm2;肌纤维密度与体型体重和肌纤维直径也没有显著的表型相关关系(P＞0.05),这种现象值得进一步深入的研究.     

Effects of probucol on the proliferation of rat vascular smooth muscle cells stimulated by basic fibroblast growth factor and hydrogen peroxide

AIM: To investigate the effect of probucol on proliferation of rat vascular smooth muscle cells(VSMC) stimulated by basic fibroblast growth factor (bFGF) and/or hydrogen peroxide(H₂O₂). METHODS: Effects of probucol on VSMC proliferation and DNA synthesis stimulated by bFGF and/or H₂O₂ were observed by means of MTT test, cell number count and [3H]-TdR incorporation. RESULTS: ①Probucol significantly inhibited proliferation and DNA synthesis in VSMC stimulated by bFGF and/or H₂O₂, with dosage-dependent manner. Cell number, A value and [3H]-TdR incorporation in group probucol+bFGF and group probucol+H₂O₂ were reduced by 40.0%, 39.1%, 45.5% and 46.9%, 45.0%, 39.5%, respectively, compared with group bFGF and group H₂O₂ (P＜0.05, P＜0.01, respectively). ②Pretreatment of VSMC with probucol for 24 h prior to bFGF and/or H₂O₂ stimulation exhibited significant inhibiton of VSMC proliferation and DNA synthesis, but after prestimulation by bFGF and/or H₂O₂ for 24 h, probucol had no influence on VSMC proliferation and DNA synthesis (P＞0.05). CONCLUSION: Probucol dramatically inhibited proliferation and DNA synthesis in VSMC stimulated by bFGF and/or H₂O₂, but had no inhibitory effect on the cell proliferation prestimulated by bFGF and /or H₂O₂.     

Role of NHE-1 in the proliferation and apoptosis of pulmonary artery smooth muscle cell in rats

AIM: To evaluate the role of Na⁺/H⁺ exchanger-1(NHE-1)in the proliferation and apoptosis of pulmonary artery smooth muscle cells in rats. METHODS: Twenty Wistar rats were equally randomized into the control group and 3-week hypoxic group. Intracellular pH (pHi) of the smooth muscle was determined with fluorescence measurement of the pH-sensitive dye BCECF-AM and the expression of NHE-1 mRNA was detected with RT-PCR. The primary culture of pulmonary artery smooth muscle cell in vitro was performed. In situ cell death detection kit (TUNEL) was used to study the effect of specific NHE-1 inhibitor, dimethyl amiloride (DMA), on the apoptosis of muscle cells which had intracellular acidification. RESULTS: pHi value and expression of NHE-1 mRNA of pulmonary artery smooth muscle cell were significantly higher respectively in the hypoxic group than those in the control group (P＜0.01). DMA elevated the apoptotic ratio significantly. The effect was enhanced when DMA concentration was augmented and the time was prolonged. CONCLUSION: With the function of adjusting pHi, NHE-1 may play an important role in the proliferation and apoptosis of pulmonary artery smooth muscle cells.     

猪血清酶和氟烷敏感性与肌肉品质关系的研究

 本文用54头ES系和30头斯格猪对血清肌酸激酶[CK，EC#-（2，7，3，2）]、乳酸脱氢酶[LDH，EC#-（1，1，1，2）]和氟烷敏感性与肌肉品质的关系进行了研究。结果表明：常规和药物应激后采血时血清CK活性与宰后45分钟肉质指标存在显著性相关（P＜0.01），血清LDH#-5同工酶和肉质指标高度相关（P＜0.001）。并且血清1ogCK值和LDH#-5同工酶在轻度PSE和正常肌肉猪之间存在极显著差异（P＜0.01）；氟烷阳性猪宰后表现典型PSE肌肉（斯格猪n=3），氟烷阴性宰后虽然未发生典型PSE肌肉，但存在轻度PSE肌肉胴体。     

Regulation of protein degradation pathways by amino acids and insulin in skeletal muscle of neonatal pigs

Background

The rapid gain in lean mass in neonates requires greater rates of protein synthesis than degradation. We previously delineated the molecular mechanisms by which insulin and amino acids, especially leucine, modulate skeletal muscle protein synthesis and how this changes with development. In the current study, we identified mechanisms involved in protein degradation regulation. In experiment 1, 6- and 26-d-old pigs were studied during 1) euinsulinemic-euglycemic-euaminoacidemic, 2) euinsulinemic-euglycemic-hyperaminoacidemic, and 3) hyperinsulinemic-euglycemic-euaminoacidemic clamps for 2 h. In experiment 2, 5-d-old pigs were studied during 1) euinsulinemic-euglycemic-euaminoacidemic-euleucinemic, 2) euinsulinemic-euglycemic-hypoaminoacidemic-hyperleucinemic, and 3) euinsulinemic-euglycemic-euaminoacidemic-hyperleucinemic clamps for 24 h. We determined in muscle indices of ubiquitin-proteasome, i.e., atrogin-1 (MAFbx) and muscle RING-finger protein-1 (MuRF1) and autophagy-lysosome systems, i.e., unc51-like kinase 1 (UKL1), microtubule-associated protein light chain 3 (LC3), and lysosomal-associated membrane protein 2 (Lamp-2). For comparison, we measured ribosomal protein S6 (rpS6) and eukaryotic initiation factor 4E (eIF4E) activation, components of translation initiation.

Results

Abundance of atrogin-1, but not MuRF1, was greater in 26- than 6-d-old pigs and was not affected by insulin, amino acids, or leucine. Abundance of ULK1 and LC3 was higher in younger pigs and not affected by treatment. The LC3-II/LC3-I ratio was reduced and ULK1 phosphorylation increased by insulin, amino acids, and leucine. These responses were more profound in younger pigs. Abundance of Lamp-2 was not affected by treatment or development. Abundance of eIF4E, but not rpS6, was higher in 6- than 26-d-old-pigs but unaffected by treatment. Phosphorylation of eIF4E was not affected by treatment, however, insulin, amino acids, and leucine stimulated rpS6 phosphorylation, and the responses decreased with development.

Conclusions

The rapid growth of neonatal muscle is in part due to the positive balance between the activation of protein synthesis and degradation signaling. Insulin, amino acids, and, particularly, leucine, act as signals to modulate muscle protein synthesis and degradation in neonates.