Growth promoting effects of carp serum components on goldfish culture cells

ABSTRACT:   The growth promoting effect of carp Cyprinus carpio serum was investigated in a medium for goldfish Carassius auratus cell culture. The cell growth rate was decreased in the L-15 medium containing carp serum free from low molecular weight (LMW) fraction of less than 10 000. The addition of this fraction to the medium recovered the original growth rate, whereas the fraction itself did not enhance cell growth. Similar experiments were carried out with carp serum lipoprotein and albumin-like protein fractions. The high density lipoprotein (HDL) fraction containing apolipoprotein (apo) A-I and apoA-II enhanced cell growth at 20°C and 35°C when added with the above-mentioned LMW fraction. A good proliferation was observed at both 20°C and 35°C with the HDL fraction at 0.58 mg/mL. Carp albumin-like protein fraction, mainly containing a 71 kDa-component, also enhanced goldfish cell growth with the LMW fraction at the two temperatures. These results suggest that HDL and albumin-like proteins play an important role in the goldfish cell growth cooperatively with LMW substances contained in carp serum.     

Lipid transport in female Fundulus heteroclitus during the reproductive season

Lipid transport during the reproductive cycle of seasonally spawning teleosts has been well described. However, there is little information on lipid transport in a multiple spawning teleost. We examined lipid transport during the reproductive cycle in Fundulus heteroclitus, a teleost that spawns in a semilunar fashion. Plasma levels of triglycerides more than double prior to spawning events and then drop off sharply around the time of spawning. Plasma levels of total cholesterol also changed throughout the spawning cycle, but those changes were not so pronounced. The fraction of lipid carried by very low density lipoprotein (VLDL) and low density lipoprotein (LDL) was greatest prior to spawning events, while high density lipoprotein (HDL) carried the greatest portion of lipid during the spawning period. Vitellogenin (Vtg) was detected prior to spawning events, but it never represented more than 5% of total plasma lipid, making it very unlikely that Vtg is responsible for the changes in plasma lipids that we observed. It is also unlikely that Vtg is solely responsible for transport of lipid to growing ovaries because it carries only a very small portion of plasma lipid. This is the first study we are aware of, that tracks changes in plasma lipids of a multiple spawning teleost with a great enough sampling frequency to resolve single spawning events. This revised version was published online in August 2006 with corrections to the Cover Date.     

余甘汁的药效学研究

用比较研究方法观察不同质量分数的余甘汁对大鼠血液血脂水平、超氧化物歧化酶活性、脂质过氧化物及小鼠耐缺氧能力的影响．结果表明，质量分数为１０×１０－２的余甘汁可使大鼠血清总胆固醇值下降（Ｐ＜０．０１），高密度脂蛋白胆固醇与总胆固醇比值升高（Ｐ＜０．０５）．质量分数为５×１０－２及１０×１０－２的余甘汁均可显著降低血清脂质过氧化物水平（Ｐ＜０．００１），提高血清超氧化物歧化酶活性（Ｐ＜０．００１）．疗效与阳性对照药γ－月见草一致．质量分数为１０×１０－２的余甘汁可延长小鼠心脏耐缺氧时间（Ｐ＜０．０５），疗效与阳性对照药吉林参煎剂一致，而质量分数为５×１０－２的余甘汁则无效（Ｐ＞０．０５）．     

Cloning and characterization of lipoprotein lipase (LPL) and the effects of dietary lipid levels on the expression of LPL in the redlip mullet (Liza haematocheila)

The genetic improvement of redlip mullet Liza haematocheila through breeding programmes is of interest for this important aquaculture species. Lipoprotein lipase (LPL) is a key enzyme in lipid deposition and metabolism. The purpose of this study was to investigate the nutritional regulation of LPL in redlip mullet. We cloned and identified the LPL gene, determined LPL gene expression in various tissues, and examined the effect of dietary lipid level on hepatic LPL gene expression. The LPL gene of redlip mullet Liza haematocheila (L.hLPL) was 2,395 bp in length and encoded 516 amino acids. Sequence analysis showed that L.hLPL shared 61%–90.3% identity with LPLs in other species. Expression patterns of hepatic L.hLPL were studied in redlip mullet fed diets containing 2.0, 4.8, 7.5, 9.8, 12.0 or 14.6 g/kg, crude fat for 60 days by real‐time quantitative PCR. The abundance of LPL mRNA in hepatic tissue increased with the increase in dietary fat. The expression L.hLPL mRNA was significantly higher in the groups fed diets with 14.6 and 12.0 g/kg fat than in the other groups (p < .05). Gene expression was significantly higher in the abdominal fat of redlip mullet (p < .05) compared with other tissues. In conclusion, a high fat diet (9.79–14.59 g/kg) induces L.hLPL expression in abdominal fat.     

LDL对玻璃化冷冻解冻培养MⅡ期猪卵母细胞线粒体膜电位和透明带泛素化水平的影响

本试验旨在探究添加低密度脂蛋白（low density lipoprotein,LDL）对玻璃化冷冻解冻后MⅡ期猪卵母细胞发育率、线粒体膜电位及透明带泛素化水平的影响。采用线粒体膜电位特异性探针JC-1检测各处理组线粒体膜电位,并采用SDS-PAGE及Western blotting方法分析不同处理组MⅡ期猪卵母细胞透明带蛋白泛素化水平。结果显示,玻璃化冷冻法处理中,10 mg/mL LDL处理组MⅡ期卵母细胞正常率和成熟率（71.92%和69.86%）显著高于对照组（58.26%和54.55%）（P<0.05）,最接近未冷冻组。10 mg/mL LDL处理组MⅡ期卵母细胞线粒体膜电位显著高于对照组、1和20 mg/mL LDL组（P<0.05）。免疫印迹结果显示,未冷冻组和LDL处理组MⅡ期卵母细胞ZP1、ZP2及ZP3蛋白分别在61、80、106 ku发生不同程度的泛素化标记;10 mg/mL LDL处理组ZPs（ZP1、ZP2、ZP3）蛋白泛素化水平显著高于1和20 mg/mL LDL组（P<0.05）,但显著低于非冷冻组（P<0.05）。结果表明LDL可改善玻璃化冷冻解冻培养后MⅡ期猪卵母细胞成熟率、线粒体膜电位及透明带泛素化水平。     

Lipid digestibility and ultrastructural changes in the enterocytes of Arctic char (Salvelinus alpinus L.) fed linseed oil and soybean lecithin

Arctic char (Salvelinus alpinus L.) were fed two isocaloric diets supplemented with 15% linseed oil or soybean lecithin, and subsequently analysed for ultrastructural changes in various intestinal segments (pyloric caeca region, midgut and hindgut) as well as apparent digestibility coefficients (ADC) of the diets. The ADC of dry matter, lipid and individual fatty acids were always highest in fish fed the soybean lecithin diet. In hindgut for example, ADC of lipid and dry matter were 94 and 96%, respectively, in fish fed the soybean lecithin diet compared to 85 and 94% in fish fed linseed oil.There were major ultrastructural differences in the enterocytes between fish fed the two experimental diets. In char fed the linseed oil diet there were substantial accumulations of lipid droplets in the enterocytes from the pyloric caeca and midgut but not in hindgut. These accumulations were not observed in fish fed the soybean lecithin diet. In some cases, deposition of fat in the enterocytes was so great that it resulted in epithelial damage with lipid droplets and cell debris appearing in the intestinal lumen. These changes are likely to be pathological and may lead to intestinal malfunction and represent a major infection route to pathogenic bacteria. On the basis of these results it is suggested that endogenous phospholipid synthesis is insufficient to maintain lipoprotein synthesis in Arctic char when fed diets containing high levels of polyunsaturated fatty acid of total lipid, and that phospholipids should be supplied with such diets.     

Dietary lipid levels affect lipoprotein clearance,fatty acid transport,lipogenesis and lipolysis at the transcriptional level in muscle and adipose tissue of large yellow croaker (Larimichthys crocea)

To investigate the effect of dietary lipid levels on lipid metabolism in muscle and adipose tissue of large yellow croaker (Larimichthys crocea), fish (average body weight 150.0 g) were fed to one of three diets with a low (6%), moderate (12%, the control diet) or high (18%) crude lipid level for 10 weeks. The expression of genes related to lipoprotein clearance (lpl, ldlr, lrp1 and srbi), fatty acid transport (cd36, fatp1, fabp3 and fabp11), lipogenesis (fas and dgat2) and lipolysis (atgl, cpt1 and aco) in muscle and adipose tissue was analysed. In muscle of fish fed the low‐lipid diet, the expression of lpl, lrp1, fas, dgat2 and atgl was significantly downregulated, whereas fabp3 and fabp11 were significantly upregulated compared with those fed the control diet. In muscle of fish fed the high‐lipid diet, the expression of lpl, ldlr, lrp1, cd36, fabp3, fas and dgat2 was significantly decreased, while fabp11 expression was significantly increased compared with those fed the control diet. Compared with the control group, only a significant downregulation of fabp3 expression in adipose tissue was observed in the low‐lipid group. In the high‐lipid group compared with the control group, the expression of ldlr, fabp11, dgat2, atgl and aco in adipose tissue was significantly upregulated, whereas cpt1 expression in adipose tissue was significantly downregulated. These results indicated that the expression of the selected key genes related to lipid metabolism was tissue‐specific regulation by dietary lipid levels in large yellow croaker.     

西伯利亚鲟卵巢发育过程血清脂蛋白脂酶活性与血脂代谢的研究

利用微创手术检查的方法对人工养殖西伯利亚鲟的卵巢发育期进行鉴别,根据卵巢发育期将西伯利亚鲟分为Ⅱ期、Ⅲ期、Ⅳ期、Ⅴ期和Ⅵ期共5个实验组。对5个实验组血清脂蛋白脂酶(LPL)活性及血脂含量进行测定,并对其之间的关系进行分析。结果表明:随着卵巢发育,血清LPL活性、极低密度脂蛋白胆固醇(VLDL-C)、甘油三酯(TG)呈"先上升,后下降"的趋势,其中LPL在Ⅴ期达到最高值,VLDL-C、TG均在Ⅳ期达到最高值;总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)随卵巢发育表现为上升趋势。血清TG与LPL呈正相关关系。     

鲤脂蛋白脂肪酶基因特性、表达分布、重组蛋白获得及酶活性比较

为研究鲤脂蛋白脂肪酶(Cc LPLs)的基因特征、时空表达分布及酶活性，实验利用基因组同源搜索获取鲤CcLPLs同源基因并分析其序列特征；通过荧光定量PCR(qPCR)方法对CcLPLs在不同组织的表达进行分析；采用原核表达系统获取CcLPLs重组蛋白，并使用对硝基苯酚法测定各重组蛋白的酶活性。结果显示，鲤基因组中挖掘到5个CcLPLs基因(CcLPLA1a、CcLPLA1b、CcLPLA2a、CcLPLA2b*和CcLPLBa)，经验证，CcLPLA2b*是假基因，共线性分析显示，鱼类特有基因组加倍过程中出现基因丢失的现象，而鲤特有的基因组加倍致使鲤存在5个CcLPLs。CcLPLA1a和CcLPLA1b核苷酸序列和氨基酸序列相同，同源性分析显示，CcLPLBa与CcLPLA1s的同源性为64%，与CcLPLA2a同源性为50.8%。qPCR结果显示，CcLPLs的表达量在肝脏、心脏、脂肪、肌肉、脑、肠道和脾脏中依次降低，在各个组织中，各基因表达量从高到底依次为CcLPLA1s、CcLPLA2a和CcLPLBa。鲤正常投喂、饥饿及再投喂状态下CcLPLA1s和CcLPLA2a在肝脏、...