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1.
Experiments were designed to compare the adipocyte cellularity of subcutaneous adipose tissue between growing Landrace (low backfat) and Meishan (high backfat) pigs at 1 week, 3 weeks, 6 weeks, 3 months and 5 months of age. As pigs aged, body weight and backfat thickness of both breeds significantly increased. When compared at equal ages, backfat thickness adjusted to equal body weight was greater for Meishan pigs. The mean diameter of fat cell size also increased with age, and by 6 weeks adipocytes from both outer and inner layers of subcutaneous adipose tissue were larger in Meishan pigs. At 5 months, approximately 80% of the adipose tissue mass in Meishan pigs was attributable to adipocytes measuring 95–165 µm in diameter, whereas adipocytes of 75–145 µm comprised most of the tissue mass in the Landrace. Although the contribution of smaller adipocytes (25–45 µm) to the tissue volume was negligible, both breeds showed a biphasic diameter distribution at all ages, suggesting that adipocyte hyperplasia is still active. Our results demonstrate that cellularity differences exist between the subcutaneous adipose tissues of Landrace and Meishan pigs, and adipocyte hypertrophy is the most overwhelming contributor to the greater backfat deposition for Meishan pigs.  相似文献   
2.
To assess the role of muscle fiber type in beef taste‐traits, we analyzed cooked meats from bovine masseter, diaphragm, psoas major, longissimus thoracis, and semitendinosus muscles with an electric taste sensing system (INSENT SA402B). The system is composed of five taste sensors of polymer membranes fixing different lipids. The sensors, CT0, CA0, AAE, C00 and AE1 are designed to respond to the individual tastes of salty, sour, umami, bitter and astringent, respectively. The system found significant differences in the converted outputs of CA0 (cvCA0), C00 (cvC00) and AE1 (cvAE1) among the bovine muscles. The slow‐type muscles (masseter and diaphragm) showed lower cvCA0, higher cvC00, and higher cvAE1 than did the fast‐type muscles (psoas major, longissimus thoracis, and semitendinosus). Lactic acid content was different among muscle types and was highly related to the cvCA0 output and pH. carbonyl compounds and free fatty acids were higher in the slow‐type muscles. Free fatty acids were major components causing the difference in the C00 output among the muscle types. Iron content was also different among the muscle types and related to the cvC00 and cvAE1 outputs. These results suggested that the muscle fiber type affects the beef taste characteristics.  相似文献   
3.
The peroxisome proliferator‐activated receptor‐γ coactivator‐1 α (PGC‐1 α) induces mitochondria biogenesis in skeletal muscles. To determine the relationships between PGC‐1 α and the muscle fiber types, the expression levels of PGC‐1 α were analyzed in porcine and bovine skeletal muscles. As a first step, the nucleotide sequences of the porcine and bovine PGC‐1 α were determined. The porcine and bovine PGC‐1 α cDNA encoded 796 amino acid sequences and showed 95.1% identity between the two species. The expression levels of the PGC‐1 α mRNA were analyzed in the same 10 skeletal muscles from four pigs and three cattle. The contents of porcine and bovine PGC‐1 α were higher in the tongue, masseter and diaphragm, and lower in the Biceps femoris, semimembranosus, Longissimus thoracis and semitendinosus muscles. The contents of myosin heavy chain slow‐type protein (MyHC‐slow) were also determined in the same muscles by ELISA. The analysis of MyHC‐slow showed results similar to those for the PGC‐1 α contents in all of the muscles except for the tongue. The content of MyHC‐slow in the tongue was the lowest among the porcine muscles, and moderate among the bovine muscles. The results suggest that PGC‐1 α relates to the development of oxidative muscle fibers, but is not the principal factor in determining type I fiber content.  相似文献   
4.
To assess both quantitative and qualitative differences between the slow‐ and fast‐type muscles, masseter (slow) and semitendinosus (fast) from four Holstein cows were analyzed by two‐dimensional difference gel electrophoresis (2D DIGE) and mass spectrometry. The proteome analysis identified 27 spots as 20 proteins in the whole protein fraction extracted with 8 mol/L urea solution, and 16 spots were identified as 11 proteins in the water‐soluble protein fraction. Two slow‐type myofibrillar proteins (myosin light chain‐1 slow‐b and myosin light chain‐2 slow), and aconitase‐2 mitochondria were present at higher levels in the masseter muscle (P < 0.05). Four fast‐type myofibrillar proteins (myosin light chain‐1 fast, myosin light chain‐2 fast, myosin light chain‐3 fast and tropomyosin‐1), and three enzymes of glycolytic pathway (enolase‐3, aldolase‐A and triosephosphate isomerase), were present at higher levels in the semitendinosus muscle (P < 0.05). Our proteome analysis showed that the composition of sarcoplasmic proteins as well as myofibrillar proteins was clearly different between slow‐ and fast‐type muscles.  相似文献   
5.
An effective bacteriocin was identified and characterized. Lactic acid bacteria were screened against Campylobacter jejuni. One bacteriocin producer, Enterococcus faecium (NRRL B-30746), was studied. The isolate was grown, and the bacteriocin was purified to single-band homogeneity. Biochemical traits indicated that the peptide was a Class IIa bacteriocin, and it was named E 50-52. The bacteriocin had a molecular weight of 3339.7 and an isoelectric point of 8.0. The minimal inhibitory concentrations of E 50-52 against C. jejuni, Yersinia spp., Salmonella spp., Escherichia coli O157:H7, Shigella dysenteriae, Morganella morganii, Staphylococcus spp., and Listeria spp. ranged from 0.025 to 32 microg/mL. In therapeutic broiler trials, oral treatment with E 50-52 reduced both C. jejuni and Salmonella enteritidis by more than 100,000-fold in the ceca, and systemic S. enteritidis was reduced in the liver and spleen. The wide range of antibacterial activity of bacteriocin E 50-52 against pathogens provides a promising alternative to antibiotics.  相似文献   
6.
2006年欧洲人畜共患病的感染情况年度总结报告,由欧盟食品安全局(EFSA)和欧洲疾病预防和控制中心(ECDC)于近期公布.该报告阐述了人畜共患病传染、媒介、抗生素抗性和食源性疾病在25个欧盟成员国和5个非成员国(保加利亚、冰岛、列支敦士登、挪威和罗马尼亚)暴发的最新趋势和发生数字.以下是该报告的背景和结果.  相似文献   
7.
The composition of tropomyosin (TPM) and myosin heavy chain (MyHC) isoforms was analyzed in 10 physiologically different bovine muscles ( masseter , diaphragm, tongue, semispinalis, pectoralis profundus , biceps femoris, psoas major , semimembranosus, longissimus thoracis and semitendinosus ) to clarify the relationships between TPM and MyHC isoforms in different muscle fiber types. The content of TPM1 and TPM3 was different in muscles according to their function in muscle contraction, although the content of TPM2 was constantly about 50% of the total TPM in all muscles. The content of TPM1 was higher in semimembranosus , longissimus thoracis and semitendinosus, while that of TPM3 was higher in masseter and diaphragm. The high positive correlation between MyHC-slow content and TPM3 content ( r  = 0.92) suggested a coexpression of TPM3 and MyHC-slow isoforms in a muscle fiber. MyHC-slow and TPM3 were expressed at the same level in masseter and diaphragm, whereas there was more TPM3 than MyHC-slow in tongue and semispinalis , so it appears that the excess TPM3 in tongue and semispinalis is expressed with other MyHC isoforms. MyHC-2a was the only fast type isoform expressed in tongue and semispinalis . Therefore, the excess TPM3 was composed of myofibrils with MyHC-2a. The results suggested that a fiber expressing MyHC-2a would be regulated delicately by changing the TPM isoform types.  相似文献   
8.
9.
The full amino acid coding sequences of adrenergic receptor genes beta1, beta2, and beta3 (ADRB1, ADRB2, and ADRB3)were determined for Jinhua, Meishan, Duroc and Landrace pigs. Non‐synonymous substitution of Arg458Pro was found in the porcine ADRB1 gene, resulting in a 469 amino acid sequence. Continuous substitutions of Asn29Asp and Glu30Gln were found in the porcine ADRB2 gene, resulting in a 418 amino acid sequence. Additionally, a Lys30 polymorphism of the ADRB2 gene was found in the Jinhua pigs. There were three non‐synonymous substitutions of Asn24Thr, Arg264Gln and Asn398Asp on the porcine ADRB3 gene. A thymine insertion in the ADRB3 gene, resulting in a protein with two fewer amino acids, was found in the Jinhua and Meishan pigs. To assess the effect of ADRB polymorphisms on porcine subcutaneous fat layer thickness, we calculated the genetic frequency of the variants in fatty and lean groups, each consisting of 24 pigs that were crossbreds of Duroc and Jinhua pigs. The effect of the ADRB3 gene polymorphism was not evaluated, because there was insufficient variation on the ADRB3 gene in the examined groups. Although Fisher's exact test showed no significant difference in the frequency of ADRB1 and ADBR2 variants between the two groups, the Arg458 variant of ADRB1 was higher (P = 0.11) in the lean group, and pigs in that group had a thinner fat layer than did those with the Pro458 variant. These results imply a possibility of ADRB1 polymorphism as a minor factor in porcine fat layer thickness. The Asp29 variant of ADRB2 was higher in the lean group (P = 0.11), and the Glu30 variant was higher in the fatty group (P = 0.15), but the Asp29 variant was found only in the Chinese pigs. Thus, the effect of ADRB2 polymorphisms was not clear in this study.  相似文献   
10.
玉树藏马血清酯酶的遗传多态性   总被引:3,自引:0,他引:3  
采用聚丙烯酰胺凝胶电泳对来源于青海省杂多县 1 0 9匹藏马血清酯酶多态性进行了测定。在藏马酯酶位座共发现 5种表型 ,由EsF、EsI 和EsS 等 3个等位基因控制 ,其基因频率分别为 0 .4 1 2 8、0 .5367及 0 .0 50 5;基因的杂合度、基因均质度指数和有效等位基因数分别为 0 .5390、0 .1 91 5和 2 .1 692。  相似文献   
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