Effects of Monoclonal Antibody Against Adipocyte-Specific Membrane Protein on Lipid Metabolism in Pigs

This study was to investigate the regulation of monoclonal antibodies against adipocyte membrane proteins （McAb） on lipid metabolism in pigs. Forty Landrace x Saba pigs were randomly divided into eight groups; the control group was given 10 mL saline and the treat groups were given monoclonal antibody against adipocyte-specific membrane protein with 0.1, 0.5, and 1.0 mg kg-I body weight at 15 and 60 kg body weight, respectively, by intraperitoneal injection. The results showed that McAb could increase, significantly, serum lipoprotein lipase activity and reduce serum nonesterified fatty acid （NEFA） content. Meanwhile, McAb increased content of serum lipid, triglyceride （TG）, cholesterol （CHO）, high density lipoprotein （HDL）, and low density lipoprotein （LDL） both at 15 and 60 kg body weight. However, McAb affected more significantly the lipid metabolism at 15 kg body weight than at 60 kg body weight. Moreover, this effect of McAb on lipid metabolism exhibited dose-dependent effect. These results suggested that this monoclonal antibody increased lipase activity, promoted lipolysis, and utilization of lipid so that McAb could be applied to restrain excessive fat deposition in porcine production through the regulation of fat metabolism.     

填饲期肥肝鹅脂肪沉积、血脂成分和脂类代谢酶的变化规律

【目的】通过对不同填饲期肥肝鹅体内脂肪沉积、血脂成分和脂类代谢酶等指标的测定分析,探讨肥肝鹅脂肪代谢规律。【方法】选取同批孵化、相同饲养条件下育成的85日龄体重差异不显著（P＞0.05）的肝用型公鹅200只进行填饲,填饲期30 d。从预试期结束起,分别于填饲0、6、12、18、24、30 d取血、屠宰1次;每次随机选取30只体重相近的试验鹅,每只为1个重复,以填饲0 d作为对照。分别测定肝重、皮脂重、腹脂重、肠脂重、皮脂率、腹脂率、肠脂率、血脂成分和脂类代谢相关指标。所有试验鹅填饲同一种饲粮,填饲量定量一致。将经过筛选的玉米粒倒入水锅内,煮沸5-10 min后,捞出沥干,趁热加入1%鹅油、0.3%的食盐并充分拌匀,冷却后作为填饲饲粮;采用双人机械填饲方法。试验鹅采用地面圈养填饲,分栏饲养。【结果】①腹脂重、皮脂重、肠脂重随着填饲时间的延长而增加,填饲12-18 d腹脂、皮脂、肠脂、肥肝脂肪沉积增重最快,填饲30 d时皮脂重＞腹脂重＞肠脂重;②除了填饲6 d皮脂率与肥肝重呈显著负相关（r=-0.869）外,不同填饲期肥肝鹅腹脂重、皮脂重、肠脂重、腹脂率、皮脂率、肠脂率与肝脏重均呈极显著正相关（P＜0.01）。③填饲显著改变游离脂肪酸（non-estesterified fatty acid,NEFA）和载脂蛋白A（apolipoprotein- A,Apo-A）的含量;在整个填饲过程中,载脂蛋白B（apolipoprotein- B,Apo-B）的含量随着填饲时间的延长有下降的趋势,但各填饲阶段之间差异均不显著（P＞0.05）;随着填饲时间的延长,甘油三酯（Triglyceride,TG）、总胆固醇（total cholesterol,TC）、高密度脂蛋白胆固醇（high density lipoprotein-cholesterol,HDL-C）、低密度脂蛋白胆固醇（low density lipoprotein-cholesterol,LDL-C）和极低密度脂蛋白胆固醇（very low density lipoprotein-cholesterol,VLDL-C）的含量逐渐增加。④胆碱酯酶（cholinesterase,CHE）、脂肪酶（lipase,LPS）、脂蛋白脂酶（lipoprotein lipase,LPL）和肝脂酶（lipoprotein lipase,HL）和总脂酶（LPL+HL）活性最大值分别出现在填饲18-24 d,并呈先升高后降低趋势。【结论】填饲显著改变肥肝鹅的机体脂肪组成;填饲能够显著改变肥肝鹅血脂成分含量,肝重与机体脂肪沉积均呈极显著正相关（P＜0.01）;填饲12-24 d是机体脂肪代谢最旺盛的时期,沉积量最多,肥肝增重最快。     

Genetic analysis of digestive physiology using fluorescent phospholipid reporters

Zebrafish are a valuable model for mammalian lipid metabolism; larvae process lipids similarly through the intestine and hepatobiliary system and respond to drugs that block cholesterol synthesis in humans. After ingestion of fluorescently quenched phospholipids, endogenous lipase activity and rapid transport of cleavage products results in intense gall bladder fluorescence. Genetic screening identifies zebrafish mutants, such as fat free, that show normal digestive organ morphology but severely reduced phospholipid and cholesterol processing. Thus, fluorescent lipids provide a sensitive readout of lipid metabolism and are a powerful tool for identifying genes that mediate vertebrate digestive physiology.     

甘草提取物对滩羊肝脏脂肪代谢关键酶活性的影响

基于本课题组前期研究发现甘草提取物有降低滩羊皮下脂肪沉积的趋势,本试验为研究甘草提取物对脂肪代谢中枢组织——肝脏脂肪代谢关键酶活性的影响,选择日龄与体重相近的滩羊公羔50只,随机分为5组,每组10只,基础日粮中甘草提取物添加水平分别为0、1 000、2 000、3 000和4 000 mg/kg.120 d后试验羊屠宰,测定肝脏甘油三酯(TG)和总胆固醇(TC)含量,脂肪酸合成酶(FAS)、还原型辅酶Ⅱ(NADPH)生成酶、肝脂酶(HL)、脂蛋白脂酶(LPL)和总脂酶(TL)活性.结果表明,甘草提取物显著降低了肝脏TG含量(P＜0.05),添加水平在1 000、2 000、3 000和4 000 mg/kg基础日粮时,与对照组(0 mg/kg)相比分别下降了28.3％、45.5％、44.0％及40.8％;同时甘草提取物显著提高了分解酶(HL、LPL和TL)活性(P＜0.05),对TC含量、FAS及NADPH生成酶活性的影响未达到显著水平(P＞0.05).据此推测,甘草提取物主要通过调节脂肪氧化途径的关键酶活性来抑制滩羊肝脏内脂肪的沉积,进而减少肝脏内脂肪向外周组织的转运,达到降低皮下脂肪沉积的作用.     

不同脱乙酰度的壳聚糖对肉鸡生长、胴体性能及脂质代谢的影响

为研究不同脱乙酰度的低分子壳聚糖对肉鸡生产性能、胴体品质及脂质代谢的影响,选1日龄健康肉鸡192只,随机分成4组,每组6个重复,每个重复8只,分别饲喂基础日粮及基础日粮中添加（0.15%）脱乙酰度为73%、81%和90%的低分子（6.75~8.84 kDa）壳聚糖日粮,试验期42 d。试验末袁每组随机抽取6只鸡（每重复1只）采集血清样品并屠宰,取肝脏、腹脂样品。结果表明,各组的平均采食量、平均日增重及料重比均差异不显著。90%脱乙酰度的低分壳聚糖组肝脂率和腹脂率分别显著降低6.08%、6.53%,血清甘油三酯和胆固醇含量也显著降低;各处理组肝脏中脂肪酸合成酶和苹果酸脱氢酶活性差异不显著袁但腹脂脂蛋白酯酶的活性有上升趋势。可见袁肉仔鸡日粮中添加不同脱乙酰度的低分子壳聚糖对其生长没有明显的影响,但高脱乙酰度的低分子壳聚糖可显著降低肉仔鸡对脂肪的吸收利用及体脂沉积,壳聚糖可能通过促进体内脂肪的分解而调节肉鸡的脂质代谢。     

Human lipoprotein lipase complementary DNA sequence

Lipoprotein lipase is a key enzyme of lipid metabolism that acts to hydrolyze triglycerides, providing free fatty acids for cells and affecting the maturation of circulating lipoproteins. It has been proposed that the enzyme plays a role in the development of obesity and atherosclerosis. The human enzyme has been difficult to purify and its protein sequence was heretofore undetermined. A complementary DNA for human lipoprotein lipase that codes for a mature protein of 448 amino acids has now been cloned and sequenced. Analysis of the sequence indicates that human lipoprotein lipase, hepatic lipase, and pancreatic lipase are members of a gene family. Two distinct species of lipoprotein lipase messenger RNA that arise from alternative sites of 3'-terminal polyadenylation were detected in several different tissues.     

Regulation of C. elegans life-span by insulinlike signaling in the nervous system

An insulinlike signaling pathway controls Caenorhabditis elegans aging, metabolism, and development. Mutations in the daf-2 insulin receptor-like gene or the downstream age-1 phosphoinositide 3-kinase gene extend adult life-span by two- to threefold. To identify tissues where this pathway regulates aging and metabolism, we restored daf-2 pathway signaling to only neurons, muscle, or intestine. Insulinlike signaling in neurons alone was sufficient to specify wild-type life-span, but muscle or intestinal signaling was not. However, restoring daf-2 pathway signaling to muscle rescued metabolic defects, thus decoupling regulation of life-span and metabolism. These findings point to the nervous system as a central regulator of animal longevity.     

肉碱对中华鳖脂肪代谢的影响

选用1 170只211日龄中华鳖进行养殖试验,研究不同剂量(0,50,100 mg/kg)的l-肉碱对中华鳖脂肪代谢的影响. 通过解剖取样测定肝脏、四肢肌肉和脂肪块的脂肪代谢酶活性及肌细胞内脂肪酸β-氧化反应等生化指标,探讨其作用机理. 结果表明,在饲料中添加100 mg/kg l-肉碱显著降低了中华鳖四肢的脂肪沉积量的27.11%(P<0.01),肝脏和脂肪中的苹果酸脱氢酶及脂肪中激素敏感脂酶总活力分别提高了24.32%(P<0.01)、32.22%(P<0.01)和14.88%(P<0.05),肌肉和脂肪中脂蛋白脂酶总活力分别提高了27.08%(P<0.01)和13.18%(P<0.05),肌肉中游离肉碱、总酸不溶肉碱含量分别升高了16.92%(P<0.01)和38.24%(P<0.01).     

Regulation of Drosophila life span by olfaction and food-derived odors

Smell is an ancient sensory system present in organisms from bacteria to humans. In the nematode Caenorhabditis elegans, gustatory and olfactory neurons regulate aging and longevity. Using the fruit fly, Drosophila melanogaster, we showed that exposure to nutrient-derived odorants can modulate life span and partially reverse the longevity-extending effects of dietary restriction. Furthermore, mutation of odorant receptor Or83b resulted in severe olfactory defects, altered adult metabolism, enhanced stress resistance, and extended life span. Our findings indicate that olfaction affects adult physiology and aging in Drosophila, possibly through the perceived availability of nutritional resources, and that olfactory regulation of life span is evolutionarily conserved.     

西洋参总皂苷及单体皂苷对胰脂肪酶活性的影响

首次对西洋参部皂苷及各单体皂进行了降脂活性的研究。结果表明：西洋参总皂苷较人参总皂苷对体外胰脂肪酶活性的抑制作用强，在0．5mg/mL浓度时抑率分别为90％和35．2％；人参皂苷Rc,Rb1,Rb2对胰脂肪酶少性均有很强的抑制作用，在0．5mg/mL浓度时抑制率分别为100％、96％、97％、初步揭示出它们具有被开发为降血脂新药的良好前景。     

亮氨酸和异亮氨酸对脂肪沉积的影响及机制

亮氨酸具有调节糖脂代谢,降低肥胖动物脂肪沉积功能。饲喂高脂日粮建立肥胖动物模型,应用RT-PCR、免疫组化技术检测脂代谢基因Ampk,Atgl,Hsl,Acc,Fas,Sirt1及其相关基因SREBP1c和PPARγ表达水平,运用16S高通量测序检测肠道菌群变化情况。结果表明,添加亮氨酸、异亮氨酸和二者混合物均显著降低脂肪重量,增加Ampk等脂解基因表达水平,降低SREBP1c等脂合成基因表达水平,提高Lachnospiraceae丰度而降低Desulfovibrionaceae丰度。亮氨酸、异亮氨酸及其混合物可通过Sirt1的介导调控脂代谢基因表达,改善肠道菌群,降低脂肪沉积,对于治疗肥胖及改善畜产品品质具有重要意义。     

桔梗抗肥胖机理试验研究

用含有桔梗水提取物的高脂肪饲料饲喂小鼠，结果表明：含5％桔梗水提取物的高脂肪饲料与对照组比较，小鼠体重和子宫周匀明显下降；同时肝脏中三酰基甘油的水平也有所降低。研究认为：桔梗总皂苷能抑制胰脂肪酶活性，可以使胰脂肪酶的活性抑制在41．7％水平上；桔梗皂苷D、桔梗皂苷A和桔梗皂苷C可分别使其活性抑制在34．8％、3．3％和5．2％的水平上。而菊糖对胰脂肪酶活性没有抑制作用，也不能抑制高脂肪饲料引起的小鼠肥胖和脂肪肝。因此，桔梗抗肥胖作用可能是由于桔梗皂苷类成分抑制胰脂肪酶活性，从而抑制对食物脂肪的吸收。     

卵形鲳鲹吸收利用配合饲料中植物油的肠道微生物的筛选

为了探讨肠道微生物在水产动物脂类代谢中的作用,提高水产动物对配合饲料中植物油的利用能力,本研究收集摄食豆油或亚麻籽油配合饲料的卵形鲳鲹(Trachinotus ovatus)幼鱼的肠道内容物,通过在培养基中添加尼罗红染液及混合脂肪酸底物的方法,从中筛选出一株能吸收亚油酸、亚麻酸的溶藻弧菌(Vibrio alginolyticus TO1);通过观察三丁酸甘油酯(tributyrin)固体培养基中的水解圈及在液体培养基中添加油脂和溴甲酚紫(bromocresol purple)指示剂方法,筛选到一株能高产脂肪酶、降解豆油和亚麻籽油的哈维氏弧菌(Vibrio harveyi TO1).这些结果表明,鱼类肠道微生物能够响应配合饲料中的脂肪源,当用植物油替代配合饲料中的鱼油时,肠道中吸收、降解、利用植物油的弧菌的丰度增加,进而参与鱼体内的脂类代谢.     

树鼩脂蛋白脂肪酶的cDNA克隆、组织分布及活性测定

目的了解不易感动脉粥样硬化动物树鼠句的脂蛋白脂肪酶的结构和活性特点,并与其它种属比较,探讨脂蛋白脂肪酶在树鼠句独特脂代谢中的作用。方法以树鼠句脂肪细胞mRNA反转录获得的cDNA一链为模板,应用SMART-RACE技术获得树鼠句脂蛋白脂肪酶的cDNA序列并推导出其氨基酸序列;实时定量PCR方法检测树鼠句脂蛋白脂肪酶mRNA在各组织中的分布;真核表达树鼠句和人脂蛋白脂肪酶蛋白,放射性同位素法测定二者的活性并比较。结果树鼠句脂蛋白脂肪酶cDNA序列全长为3293bp,其中编码区1437bp,编码20个氨基酸的信号肽和458个氨基酸的成熟蛋白,该成熟蛋白N-端比人脂蛋白脂肪酶多10个氨基酸。树鼠句脂蛋白脂肪酶与其它哺乳类动物的氨基酸序列同源性大于90%,功能域高度保守。树鼠句脂蛋白脂肪酶的组织表达谱比较广泛,在心肌和脂肪组织中大量表达,但在骨骼肌中未检测到,却在肝脏中有中低水平表达,与人脂蛋白脂肪酶在这两种组织中的表达相反。活性测定结果显示,树鼠句脂蛋白脂肪酶活性显著高于人(7.67倍),这与测定的树鼠句血浆低甘油三酯水平相符。结论树鼠句的高活性脂蛋白脂肪酶可能是其血浆低水平甘油三酯的主要原因。     

脂蛋白脂酶基因及其多态性研究进展

脂蛋白脂酶主要催化乳糜微粒和极低密度脂蛋白中的甘油三酯水解产生不饱和脂肪酸和单酰甘油,影响脂肪代谢,是动物肉质候选基因。综述了脂蛋白脂酶的生物学功能、基因结构,以及多态性与动物肉质关联的研究进展。     

A mutant Drosophila insulin receptor homolog that extends life-span and impairs neuroendocrine function

The Drosophila melanogaster gene insulin-like receptor (InR) is homologous to mammalian insulin receptors as well as to Caenorhabditis elegans daf-2, a signal transducer regulating worm dauer formation and adult longevity. We describe a heteroallelic, hypomorphic genotype of mutant InR, which yields dwarf females with up to an 85% extension of adult longevity and dwarf males with reduced late age-specific mortality. Treatment of the long-lived InR dwarfs with a juvenile hormone analog restores life expectancy toward that of wild-type controls. We conclude that juvenile hormone deficiency, which results from InR signal pathway mutation, is sufficient to extend life-span, and that in flies, insulin-like ligands nonautonomously mediate aging through retardation of growth or activation of specific endocrine tissue.