五指山猪和长白猪背最长肌蛋白组学研究

为比较五指山猪和长白猪生长后期肌肉生长发育的差异,以6、8月龄五指山猪和长白猪为试验对象,采用同位素标记相对和绝对定量技术(iTRAQ)对其背最长肌总蛋白进行鉴定,结合生物信息学技术筛选品种间和品种内差异蛋白,并对其进行KEGG通路富集分析。结果表明：4组样品中共鉴定到1713个蛋白;五指山猪和长白猪品种间比较,6、8月龄猪中分别有460、337个差异的蛋白;品种内2个生长阶段比较,五指山猪和长白猪中分别有421、275个差异蛋白;2种比较均为上调的差异蛋白数多于下调差异蛋白数;KEGG通路分析发现,在五指山猪和长白猪品种间,6、8月龄在2个品种间的差异蛋白富集到差异显著(P<0.05)的条目分别为34、33个,在品种内,五指山猪和长白猪在2个生长阶段间的差异蛋白富集到差异显著(P<0.05)的条目分别为24、14个;在品种内发现了调控骨骼肌分化过程中发挥着重要作用的PI3K/AKT信号通路和影响脂肪沉积的PPAR信号通路,在品种间除了这2种外,还发现有肌纤维类型发育相关的糖酵解/糖异生信号通路;品种内2个比较组在PPAR和PI3K/AKT信号通路分别有10、9个共同表达的基因,品种间2个比较组在糖酵解/糖异生、PI3K/AKT和PPAR信号通路分别有10、13、9个共同表达的基因,对这些信号通路中共同表达的基因进行分析后筛选到一些与肌肉生长发育和脂肪代谢相关的关键基因。     

Effects of extended postmortem aging and intramuscular location on protein degradation,muscle fiber morphometrics,and tenderness of beef longissimus lumborum and semitendinosus steaks

The objective of this study was to determine effects of extended aging and intramuscular location on Warner-Bratzler shear force (WBSF), muscle fiber cross-sectional area (CSA), and protein degradation of semitendinosus (ST) and longissimus lumborum (LL) steaks. Left ST and LL were removed from 40 carcasses at 6 d postmortem. The ST was fabricated into five locations (LOC), with LOC 1 being most proximal and LOC 5 being most distal. The posterior LL was fabricated into 3 LOC, with LOC 1 being most anterior. Vacuum sealed ST steaks were aged 7, 14, 28, 56, or 112 d postmortem, while LL steaks were aged 7, 28, or 112 d postmortem at 2 ± 1 °C. A steak from each LOC was assigned to WBSF or laboratory analyses. There were no Day of Aging (DOA) × LOC interactions for all dependent variables (P > 0.06). There were DOA effects for ST and LL WBSF values and degraded 38-kDa desmin (DES; P < 0.01). Day-7 ST-steak WBSF value was greater than all other days (P < 0.01) and day-14 steaks had greater WBSF value than remaining days (P < 0.05). Day-28 ST-steak WBSF values were greater than day 56 and 112 (P < 0.01), which did not differ (P = 0.53). In the LL, day-7 steaks had greater WBSF values than the other two timepoints (P < 0.01) and day-28 steaks had greater (P < 0.01) WBSF values than day-112 steaks. Degraded ST 38-kDa DES content was less on day 7 and 14 compared to all other days (P < 0.03), but did not differ (P = 0.79) from each other. Days 28 and 56 38-kDa DES content was less than day 112 (P < 0.01), but did not differ (P = 0.34) from each other. Degraded LL 38-kDa DES content was less on day 7 than day 28 and 112 (P < 0.02), which did not differ (P = 0.67). There were LOC effects for only ST WBSF and muscle fiber CSA (P < 0.05). Semitendinosus steak LOC 1 and 2 had greater WBSF values than all other locations (P < 0.01), but did not differ (P = 0.32) from each other. Semitendinosus steak LOC 3 and 5 had greater WBSF values than LOC 4 (P < 0.01), but did not differ (P = 0.85) from each other. The CSA of all ST fiber types were largest in LOC 1 compared to all other fiber types (P < 0.01). The CSA of all LOC 2 and 3 fiber types was greater than LOC 4 and 5 (P < 0.01), but were not different from each other (P > 0.81), and LOC 4 had greater CSA than LOC 5 (P < 0.01). Steak aging WBSF value improvements seemed proteolysis catalyzed, while the ST intramuscular tenderness gradient was more likely due to muscle fiber CSA.     

基于KFCM和改进分水岭算法的猪肉背最长肌分割技术

提出一种利用核模糊C均值聚类(KFCM)和改进分水岭算法分割猪肉眼肌切面图像中背最长肌区域的方法.该算法对经中值滤波去噪后图像的R分量利用最大方差自适应阈值(OTSU)去除背景,再采用KFCM提取出肌肉组织,然后进行空洞填充,最后由改进的分水岭算法分割出背最长肌区域.利用该算法对采集的60幅猪肉眼肌图像进行处理,分割正确率为86.67%;与传统的形态学算法相比,该算法能真实、完整地恢复出背最长肌区域.结果表明:该算法能有效地分割出猪肉眼肌图像中的背最长肌区域,与改进前分水岭算法相比,能避免背最长肌区域出现欠分割.     

基于代谢组学筛选表征茶花鸡肌肉中特征风味的水溶性化合物

【目的】利用代谢组学结合多元统计学方法筛选热处理前后茶花鸡胸肌和腿肌中的生物标志物,旨在明确表征茶花鸡不同部位肌肉中特征风味的水溶性化合物,为建立优质地方鸡评价标准提供科学理论依据。【方法】以300日龄的云南茶花鸡为研究对象,采用液相色谱-四极杆静电场轨道阱-质谱法(LC-Q-Exactive-MS)检测热处理前后胸肌和腿肌中的水溶性化合物,基于数据库Metlin进行全谱鉴定,以2-氯苯丙氨酸浓度计算各物质相对含量,并对检测出的物质进行分析,利用正交偏最小二乘法(orthogonal partial least squares discrimination analysis,OPLS-DA)建立代谢物表达量与样本组之间的关系模型,来实现对样品类别的预测,通过S-plot图初步筛选具有代表性的生物标志物,观察置换200次检验图的直线斜率判定模型是否存在过拟合现象,并且通过计算变量投影重要度(variable important for the Projection,VIP)判别各代谢物表达模式下对各组样本分类判别的影响强度和解释能力,达到辅助筛选标志物的目的;通过相对含量结果计算滋味活性...     

Study on the Function of MYLPF Gene of Muscle Growth in Cattle

This study was aimed to investigate the expression level of myosin light chain,phosphorylatable,fast skeletal muscle (MYLPF) gene in the tissues of Black cattle, and its expression level in the longissimus dorsi muscle of Black cattle and Luxi cattle, and to lay the foundation for the study of its relationship with muscle growth and development. The MYLPF gene expression level in 10 tissues of longissimus dorsi, heart, lung, liver and spleen and so on were detected by Real-time quantitative PCR, and then the changes of MYLPF gene expression level in longissimus dorsi of Black cattle and Luxi cattle at 2, 6, 10 and 12 months of age were studied. The results showed that MYLPF gene was highly expressed in the longissimus dorsi, lowly expressed in the heart, and the other tissues were almost not expressed. The MYLPF gene expression level in the longissimus dorsi was high in 2, 6, 10 and 12 months, with the increase of age,the MYLPF gene expression level decreased gradually, the expression level of 2 months of age was the highest, which was extremely significantly higher than that of the other three periods (P<0.01). The MYLPF gene expression level in the longissimus dorsi of Black cattle was higher than that of Luxi cattle in four period, which in 10 months of age were extremely significantly different (P<0.01), 2 and 12 months of age had significant difference (P<0.05), the difference in 6 months of age was not significant (P>0.05). The results suggested that MYLPF gene in the longissimus dorsi might play a regulatory role in the growth and development of skeletal muscle, which might provide a reference for studying the mechanism of growth and development of skeletal muscle and the molecular mechanism of muscle growth.     

滩羊和湖羊背最长肌全基因组甲基化差异分析

本研究旨在通过不同品种绵羊背最长肌的全基因组甲基化差异分析,鉴定差异甲基化区域（DMR）和差异甲基化基因（DMG）,为解析绵羊骨骼肌发育差异奠定基础。采用全基因组重亚硫酸盐测序（WGBS）技术开展了周岁龄滩羊、湖羊和滩湖F2代背最长肌全基因组DNA的甲基化水平检测和差异甲基化区域分析,探讨品种间DNA甲基化水平的差异。结果显示,全基因组范围内滩羊、湖羊和滩湖F2代胞嘧啶（C）甲基化（mC）率分别为3.55%、3.18%和3.56%,3个群体的甲基化水平基本一致。对滩羊和湖羊的甲基化水平进行比较,在不同序列环境下共检测到97 731个DMRs和10 784个DMGs。在CG、CHH、CHG序列环境下3个群体甲基化水平无显著差异。对DMGs通过基因本体（GO）和相关信号通路（KEGG）分析,共检测到419个GO条目和20个信号通路,显著富集在细胞过程、细胞组分、结合、长期抑制等相关条目中。筛选出5个与肌肉调控有关的候选基因ACTA2、ROCK1、CALD1、MYH3、MYH10。本研究绘制了滩羊、湖羊和滩湖F2代全基因组甲基化图谱,为表观遗传调控肌肉发育研究和肉质候选基因的筛选提供理论参考。     

Insulin-receptor binding in skeletal muscle of trout

Two hundred rainbow trout (Oncorhynchus mykiss) age 0 +, weight range 11.3 – 11.5 g, were distributed randomly in two groups and maintained for five weeks on either 10% dextrin, or 20% dextrin diet. The fish were sampled 3–5 h and 18–20 h after the last feeding and insulin binding to partially purified insulin receptors in white and red skeletal muscles and to liver plasma membranes was assessed. Plasma insulin, plasma glucose, and liver glycogen content were analyzed in the same fish.Fish fed a diet with higher carbohydrate content (HC) had elevated insulin and glucose levels in peripheral blood, but lower liver glycogen contents compared to the fish fed a diet with lower carbohydrate content (LC). No growth retardation was observed in the fish from HC group.Three to five hours after the last feeding, insulin-receptor binding in white skeletal muscles was higher in HC group of fish, mostly because of an increase in number of high affinity binding sites. Eighteen to twenty hours after the last feeding this difference disappeared. In contrast, the specific binding of insulin to the liver plasma membranes appeared to be lower in the HC group of fish. The lower insulin binding to the liver plasma membranes observed 3–5 h after feeding, could be attributed to the lower quantity of binding sites, while the same phenomenon 18 h after feeding was likely a result of affinity changes. We conclude that higher glycemic levels observed in trout fed a HC diet as compared to LC group of fish, are not a consequence of impaired binding of insulin to its receptors in skeletal muscles.Presented in part at the Annual Meeting of American Society of Zoologists, December 26–30, 1989, Boston, U.S.A. Supported by a grant (Personal investigador en el extranjero) of Ministerio de Educacion y Ciencia, (CYCIT) Spain to J.G. and by grants of the U.S. National Science Foundation (DCB 8615551 and DCB 8915935 to E.P.) and North Atlantic Treaty Organization (NATO) 0926/87 to C. Ottolenghi and E.P.     

蒙古绵羊肌肉中共轭亚油酸加工稳定性研究

为探索不同食品加工工艺及条件对肉制品中共轭亚油酸(Conjugated Linoleic Acid，CLA)的影响，在110只5月龄的内蒙古苏尼特绵羊宰杀后取背最长肌肉（Longissimus Dorsi，LD）为样品，采用气—质联用技术分析研究辐射、冻藏、加热、腌制等加工对背最长肌中共轭亚油酸稳定性的影响。结果表明，空气包装、-2℃贮藏条件下，2 kGy的γ射线可降低肌肉中共轭亚油酸含量(P<0.05)，但同样的辐射条件下，真空包装、-2℃贮藏30 d肌肉中共轭亚油酸含量很稳定。经2 kGy的γ射线灭菌，采用真空或空气包装，-18℃贮藏45 d后共轭亚油酸仍然很稳定。贮藏时间对CLA含量的影响不显著。紫外线灭菌不会引起共轭亚油酸损失。低温巴氏杀菌(70～72℃、82～86℃)可使共轭亚油酸含量降低(P<0.05)。腌制中氯化钠和亚硝酸钠的浓度对共轭亚油酸含量的影响作用显著(P<0.05)。该研究对于实际生产中确定合理的工艺参数，保持肉类产品天然成分具有指导意义。     

云南地方云岭黑山羊和龙陵黄山羊羔羊肉品质的研究

试验对云南地方云岭黑山羊和龙陵黄山羊羔羊肉的理化特性和风味品评进行研究。新出生的云岭黑山羊和龙陵黄山羊各16头用于本试验。试验山羊采用白天放牧、晚上补饲的半放牧饲养方式,补充饲料粗蛋白18.5%、代谢能12.5 MJ/kg。饲养150 d后屠宰云岭黑山羊和龙陵黄山羊羔羊各8头,取背最长肌分析肉品质。结果表明:宰后45min和24 h云岭黑山羊和龙陵黄山羊背最长肌的肉色评分、CIELAB L*、a*和C值差异不显著(P>0.05)。云岭黑山羊背最长肌的剪切力显著低于龙陵黄山羊(P=0.05)。云岭黑山羊背最长肌粗脂肪含量(P=0.03)、多汁性评分(P=0.03)和总体口感评分(P=0.04)显著大于龙陵黄山羊。本试验结果表明,云岭黑山羊羔羊肉与龙陵黄山羊相比具有较高粗脂肪含量和较优的风味口感。     

云南主要地方牛种横纹肌组织形态学研究

 采用组织学、电镜方法对云南主要地方牛种大额牛、云南瘤牛、中甸牦牛、迪庆黄牛和中甸犏牛的肌纤维特性作了系统研究.5个牛种背最长肌的肌纤维直径(μm)分别为57.48±1.15,109.45±1.84,100.38±6.25,90.38±5.31和97.35±9.62;肌纤维密度(根/mm²)分别为201.54±2.66,115.45±4.04,106.30±10.10,90.38±5.31和92.35±9.62;肌束内纤维数(根)分别为73.23±8.90,34.32±8.77,36.32±8.30,47.62±8.90和40.40±8.79.肌节长度(μm)以大额牛公牛最长(1.706 5),云南瘤牛去势公牛居中(1.467 0),云南瘤牛公牛最短(1.205 0).