绵羊肌肉IGF-IR基因表达的发育性变化研究

[目的]为绵羊的生长发育研究提供基础资料。[方法]以2、30、60、90、120日龄雄性哈萨克羊和2、30、60、90日龄新疆细毛羊为试验动物,对其肌肉IGF-IR基因进行PCR扩增,并对扩增产物进行电泳检测和序列分析。[结果]绵羊肌肉IGF-IR基因PCR扩增产物在琼脂糖凝胶上出现了287和379 bp2条带,该基因与牛IGF-IR基因序列的同源性为98.59%;在整个研究过程中,哈萨克羊IGF-IRmRNA表达量较低、较稳定,仅在30日龄时略有上升;新疆细毛羊IGF-IRmRNA表达量在2日龄时较高,30日龄时略有下降,60日龄时达到最高峰,90日龄时降到最低水平,且各日龄表达量差异显著;哈萨克羊mRNA表达量在2~60日龄时显著低于新疆细毛羊,而90日龄时显著高于新疆细毛羊。[结论]绵羊肌肉IGF-IR基因表达存在较大的品种间差异。     

家蚕副肌球蛋白/小副肌球蛋白基因的克隆及进化分析

[目的]克隆家蚕副肌球蛋白／小副肌球蛋白基因,分析该基因与运动性状的关系。[方法]利用PCR扩增和RACE技术获得了家蚕（Bombyx mori）副肌球蛋白的全长cDNA和小副肌球蛋白的部分cDNA;经检索家蚕wgs（基因组散弹序列）数据,获得了家蚕副肌球蛋白／小副肌球蛋白的基因组序列,并确定其基因组结构。[结果]家蚕PM/mPM基因由17个外显子和16个内含子组成,通过基因内部选择性启动子的使用,该基因组序列同时编码副肌球蛋白和小副肌球蛋白,小副肌球蛋白和副肌球蛋白共用最后6个外显子。家蚕副肌球蛋白与其他无脊椎动物副肌球蛋白的聚类分析表明,家蚕和野桑蚕有最近的亲缘关系,在昆虫纲中与黑腹果蝇关系最远。[结论]家蚕和野桑蚕副肌球蛋白的氨基酸序列间不存在可引起飞行缺陷的点突变,推测家蚕和野桑蚕飞行能力差异存在其他调控机制。     

电刺激改善牛肉嫩度的蛋白质组学研究

[目的]研究电刺激处理对宰后成熟过程中牛肉蛋白质的影响。[方法]利用牛背最长肌双向电泳凝胶体系研究电刺激后牛背最长肌中的差异蛋白质,分析宰后1和3 d时电刺激处理牛背最长肌中有显著降解的差异蛋白点。[结果]与未电刺激样品相比,在宰后1和3 d电刺激处理牛背最长肌中有12个蛋白点表达明显下调,分为9种蛋白质:肌间线蛋白、肌钙蛋白-T、肌球蛋白结合蛋白H;肌酸激酶、磷酸丙糖异构酶;过氧化物氧化还原酶、磷脂酰乙醇胺结合蛋白;组蛋白、甲基转移酶。[结论]电刺激后9种蛋白质通过4条途径影响电刺激后嫩度变化,包括糖酵解代谢途径、钙激活中性蛋白酶途径、溶酶体途径和氧化应激途径。电刺激通过通过4条途径影响嫩度的信号通路表明,牛肉嫩化与氧化、凋亡有密切联系;电刺激在一定程度上抑制增殖,加速氧化和凋亡,加快嫩化。     

野生及人工养殖暗纹东方肌肉营养成分的比较分析

[目的]为评价暗纹东方的营养学价值,并对其人工配合饲料的研制提供科学依据。[方法]对野生及人工养殖暗纹东方的肌肉营养成分和营养品质进行比较分析。[结果]野生暗纹东方的粗蛋白、粗脂肪、粗灰分含量及氨基酸总量、必需氨基酸总量、半必需氨基酸总量均高于养殖暗纹东方。野生与养殖暗纹东方4种鲜味氨基酸的总量分别为17.59%和14.44%(干重百分比),必需氨基酸指数(EAAI)分别为52和40,其构成比例均符合FAO/WHO的标准。暗纹东方的第一限制性氨基酸为缬氨酸。[结论]野生及养殖暗纹东方肌肉均为优质的动物蛋白食品,而野生暗纹东方的蛋白质营养价值要高于养殖暗纹东方。     

大鼠快慢骨骼肌肌纤维构成的比较

[目的]研究成年大鼠快肌内侧腓肠肌与慢肌比目鱼肌内各型肌纤维的分布及构成差异。[方法]应用RT-PCR方法分析4型肌纤维的肌球蛋白重链异构体基因表达差异,并以肌动球蛋白腺苷三磷酸酶组织化学染色分析4型肌纤维构成比例。[结果]通过RT-PCR扩增所得的条带,在内侧腓肠肌内MHCⅠ、MHCⅡx、MHCⅡa、MHCⅡb基因表达均有分布,而在比目鱼肌中未发现有Ⅱb型基因表达。4型或3型肌纤维均呈交错式镶嵌型分布。[结论]大鼠内侧腓肠肌中ⅡA型肌纤维占很大比例,而在比目鱼肌中I型肌纤维最多,其中缺少ⅡB型肌纤维。     

盐度对金鳟幼鱼肌肉品质的影响

探讨了盐度驯化对金鳟(Oncorhynchus mykiss)幼鱼肌肉品质的影响.结果表明,盐度驯化对金鳟肌肉硬度、胶着性和咀嚼性无显著影响,但盐度为32时,回弹性最高,盐度为24时,金鳟肌肉的白度最高,显著高于对照组,亮度无显著性差异,但盐度为16时,肌肉颜色偏红.盐度驯化对金鳟肌肉水分、粗脂肪和粗蛋白含量无显著影响...     

Molecular regulation of lipid metabolism in liver and muscle of rainbow trout subjected to acute and chronic insulin treatments

Although the metabolic actions of insulin in fish have been investigated widely in the past several years, lipid metabolism has received little attention, especially in tissues like the liver or white muscle. In the present study, rainbow trout received insulin treatments both acutely (intraperitoneal injection) and chronically (through mino-osmotic pumps) to elucidate hormone metabolic actions at molecular levels on the 2 main insulin target tissues in trout, namely, liver and muscle. Plasma and free fatty acid concentrations in plasma, as well as mRNA measurements of some key enzymes involved in lipid metabolism, were assessed in these tissues after 6 h and 4 d of acute and chronic insulin treatments, respectively. Our results showed that although fish received the same final total amount of hormone in both treatments, the actions of insulin on lipid metabolism were both time and tissue dependent. After the acute insulin treatment, the main anabolic role of insulin was reflected in decreased plasma free fatty acid concentrations linked to enhanced hepatic lipogenesis. We also found that insulin increased the mRNA levels of enzymes involved in lipid oxidation, perhaps to counteract insulin-induced hypoglycemia. In contrast, our data show that after chronic insulin treatment, liver and muscle exhibit different metabolic strategies: whereas in the liver chronic insulin-induced hypoglycemia may stimulate lipolytic processes to spare glucose stores, the muscle responds directly to the anabolic hormone action by increasing its lipogenic capacity and by inhibiting pathways of lipid oxidation.     

Intravenous Administration of Azumolene to Reverse Malignant Hyperthermia in Swine

Background: The efficacy of intravenous (IV) administration of azumolene (Az), an analogue 30‐fold more soluble than dantrolene, on pigs susceptible to malignant hyperthermia (MH) is incompletely understood. Objective: To evaluate efficacy of Az on MH crisis in pigs. Animals: Eight normal (MHN) and 7 susceptible to MH (MHS) pigs (Landrace × Large White × Pietran). Methods: Prospective, laboratory trial. Hypermetabolic crisis was observed in MHS pigs, but not in MHN pigs, after a combined administration of inhaled halothane (1.5%) and IV injection of succinylcholine (SCh; 2.5 mg/kg). Susceptibility was confirmed using a caffeine and halothane contracture test. Az was administered 15 minutes after administration of SCh. Results: Respiratory acidosis (pH 7.16 ± 0.02; Pco ₂, 46.2 ± 9.1 mmHg, HCO₃, 22.5 ± 2.3 mmol/L), fever (38.2 ± 1.1°C), cardiac arrhythmias, and muscle contracture were observed in MHS pigs. MHS pigs (n = 5) treated with Az (2 mg/kg IV) survived the crisis with attenuation of signs (pH 7.30 ± 0.10; Pco ₂, 36.3 ± 4.5 mmHg; HCO₃, 22.9 ± 2.3 mmol/L) and recovery of normal muscle tone and cardiac rhythm. Conclusions and Clinical Importance: Az represents a possible substitute for dantrolene to reverse MH crisis in susceptible pigs.     

刺猬肌肉、脂肪品质及营养成分分析

对野生动物刺猬（Ｅｒｉｎａｃｅｕｓｅｕｒｏｐａｅｕｓ）肌肉、脂肪的品质及营养成分进行器官及理化检验。结果表明,刺猬肌肉含蛋白质２０２％,脂肪８％,矿物质１％,熟肉率６１２％,肌纤维直径１８９５±３４５μｍ,脂肪熔点２０℃～３０℃,碘价９４～９９,皂化价１７０～１７５。肌肉的品质及营养成分可与常用动物肉（猪、牛、羊、鸡、兔肉）相媲美;油脂与常用动植物油脂相比,感官指标良好,脂肪酸不饱和程度明显高于动物油脂,而与花生油等多种植物的不饱和程度相当。     

β-激动剂克伦特罗在猪肝脏和肌肉组织中的残留

本文报道用高效液相色谱法检测β 肾上腺素能激动剂（克伦特罗Ｃｌｅｎｂｕｔｅｒｏｌ）在猪肝脏和背最长肌中的残留量。在肥育猪日粮中添加３ｍｇ／ｋｇ克伦特罗,试验期３０天,停药０、１、２、３、４天屠宰取肝脏和肌肉样。组织经匀浆浓缩提取,色谱条件为：ＣＬＣ ＯＤＳ色谱柱;以２０ｍｍｏｌ／ＬＫＨ２ＰＯ４＋３０μｍｏｌ／ＬＥＤＴＡ（ｐＨ３．９）乙腈＝８２１８（Ｖ／Ｖ）为流动相;紫外检测波长为２４３ｎｍ。结果表明,克伦特罗最低检测限为２ｎｇ／ｇ。停药当天（０天）肝脏和肌肉组织残留量分别为２０８．５ｎｇ／ｇ和１０．０ｎｇ／ｇ。停药后残留量迅速下降,肌肉在停药后第２天即检测不出,而肝脏要到第４天才检测不出。