牛肌肉生长抑制素基因的研究进展

肌肉生长抑制素,属TGF-β超家族,是一种骨骼肌生长发育的负调控因子。其生物活性的丧失或受到抑制,会导致骨骼肌增生从而引起动物肌肉的过度发育,表现为双肌性状。本文综述了MSTN基因的发现、结构特点、作用机制、在牛科物种中的研究进展及其应用前景。     

Utility of the discriminant analysis to categorize untrained Spanish Pure Bred horses on the basis of biochemical and muscle variables before and after a standardized exercise test

We hypothesized that the information obtained from a discriminant analysis could be used to objectively discriminate horses untrained from early ages, in agreement with certain physiological characteristics.In the biopsies of 24 Spanish Pure Bred horses (1.5–3 years old) before and after a standardized exercise test (SET; 4–7 m/s with a change of velocity of 1 m/s every 2 min) muscle enzymes, substrate and metabolites were determined. Also, diverse plasma and blood parameters were considered.Three pre-exercise groups (A1: six horses; A2: seven horses and A3: eleven horses) and two post-exercise groups (B1: sixteen horses; B2: eight horses) were defined from a correspondence analysis. Forward stepwise discriminant analysis selected 11 variables which differentiated the groups between each other both pre- and post-exercise.The results of the present study suggested the utility of a discriminant analysis to categorize horses in agreement with certain physiological variables. It could be used for establishing different types of training in each group by expert trainers.     

Biochemical and Antioxidant Changes in Plasma, Serum, and Erythrocytes of Horses before and after a Jumping Competition

We designed an experiment to determine the concentrations of a marker of lipid peroxidation in erythrocytes of horses submitted to jumping competitions. Erythrocytes of exercised horses showed a significant increase in the concentration of thiobarbituric acid-reactive species content immediately after exercise (P < .001), which returned to normal levels 24 hours after exercise. Nonprotein sulfhydryl groups and superoxide dismutase activity (EC 1.15.1.1) in erythrocytes were significantly higher 24 hours after exercise, as compared with the resting period and control group (P < .001). Immediately after exercise, horses had increased serum concentrations of uric acid (P < .002) and plasma lactate, as well as increased creatine kinase (EC 2.7.3.2) and lactate dehydrogenase (EC 1.1.1.28) activities (P < .001), as compared with resting period and control group. All parameters returned to normal values 24 hours after exercise, except for uric acid serum levels that remained increased (P < .001). We conclude that the oxidative stress in erythrocytes of exercised horses may contribute to tissue damage. In addition, our results showed that horses submitted to a jumping competition showed higher production of free radicals and as a consequence, lipid peroxidation.     

Comparison of enzyme activities and gene expression profiling between yak and bovine skeletal muscles

The objective of the present study was to reveal the differences between yak (Bos grunniens) and cattle in energy metabolic characteristics and gene expressions in skeletal muscles. Activities of lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and β-hydroxyacyl-CoA dehydrogenase (HOAD), which are involved in metabolism of carbohydrate and fatty acid respectively, were measured in longissimus dorsi and biceps femoris. Yak contained higher total LDH activity and higher proportion of LDH5 in longissimus dorsi than cattle (P < 0.05), indicating its more anaerobic potential characteristics in carbohydrate metabolism. However, yak contained higher activities of MDH and HOAD (P < 0.05) in biceps femoris than cattle, exhibiting high oxidative capacity under hypoxic environment. Semi-quantitative RT-PCR analysis of mRNA abundance showed that yak and cattle contained a similar level of adipocyte fatty acid-binding protein (A-FABP) in both longissimus dorsi and biceps femoris, while myosin heavy chain I (MyHC I) in longissimus dorsi and biceps femoris, and peroxisome proliferator-activated receptor coactivator 1α (PGC-1α) level in biceps femoris were significant lower in yak compared with cattle (P < 0.01 and P < 0.05 respectively), indicating the anaerobic characteristic of yak skeletal muscles. In conclusion, our experiment showed that yak skeletal muscles exhibit different energy metabolic property and gene expressions compared to cattle.     

Inhibitory effect of antisense eukaryotic expression vectors for c-myc on rat airway smooth muscle cells

AIM: To observe the inhibitory effect of antisense eukaryotic expression vectors for c-myc on rat airway smooth muscle cells. METHODS: Antisense and sense eukaryotic expression vectors for c-myc pcDNA3-myc-antisense and pcDNA3-myc-sense were constructed. Lipofectin was used to introduce antisense and sense eukaryotic expression vectors for c-myc into rat. The inhibitory effect was assayed by MTT cell proliferation assay. Cell cycles were detected by flow cytometry technology. The expression of c-Myc was detected by immunohistochemistry. RESULTS: The results showed that antisense eukaryotic expression vector for c-myc inhibited rat airway smooth muscle cells proliferation. Rat airway smooth muscle cells were prohibited in S phase and the expression of c-Myc was decreased after antisense eukaryotic expression vectors for c-myc were transfected into cells. CONCLUSION: Antisense eukaryotic expression vectors for c-myc inhibit rat airway smooth muscle cell proliferation.     

Lipid and fatty acid compositions of muscle from farmed and wild adult turbot

The aim of this study was to compare the total lipid, neutral lipid, phospholipid contents, phospholipid class distribution and fatty acid composition of these lipids in muscle of wild and farmed turbot (Scophthalmus maximus) of similar body size. The results showed that muscle of farmed turbot had a higher lipid content than that of wild turbot (1.06% versus 0.64%) because they contained more neutral lipids (0.52% versus 0.24%) and more phospholipids (0.54% versus 0.40%).Distribution of phospholipid classes in muscle of both wild and farmed turbot was similar with 67–70% phosphatidyl choline, 22–25% phosphatidyl ethanolamine and 4.4–5.2% phosphatidyl inositol plus phosphatidyl serine and 2.4–2.9% sphingomyeline.Compared to wild turbot, all of the lipid classes from farmed turbot contained lower proportions of long chain -3 PUFA and 20:4 -6 and conversely higher proportions of 20:1 and 22:1. The ratio between -3 and -6 polyunsatured fatty acids was higher in all the lipid fractions of wild turbot than in those of farmed fish (8.8 versus 4.2 in total lipids, 11.0 versus 3.3 in neutral lipids, 7.9 versus 4.7 in phospholipids). © Rapid Science Ltd. 1998     

The content of total mercury and methylmercury in common carp from selected Czech ponds

The aim of the present study was to investigate concentrations of total mercury (THg) and methylmercury (MeHG) in the common carp from Czech ponds of Rožmberk, Spolsky, Nezmar, and Velky Bědny. Seven common carps (Cyprinus caprio) from each of the ponds were caught. Muscle tissue, the liver, and the soft and hard roe were used for the tests. Total mercury and methylmercury were found in all the muscle tissue samples examined. Detection limits for total mercury and methylmercury determination methods were 0.001 mg kg^–1 and 0.013 mg kg⁻¹ respectively. Methylmercury levels in the liver and gonads were below the method’s limits of detection. THg and MeHg concentrations in muscle tissues were 0.018–0.063 mg kg^–1 w.w. and 0.019–0.063 mg kg^–1 w.w. respectively. MeHg made up 90–100% of THg in muscle tissues. Total mercury and methylmercury concentrations were significantly (P < 0.05) higher in fish from the Spolsky pond than from the Nezmar pond. MeHg/THg ratios were significantly (P < 0.05) higher in fish from the Rožmberk, Spolsky and Nezmar ponds compared with fish from the Velky Bědny pond.     

中国对虾肌肉提取物在加热过程中成分含量的变化

研究加热过程中对中国对虾肌肉的水溶性提取物中成分的影响，水溶性提取物在６５、７５、８５和９５℃加热１ｈ后，某些成分如Ｇｌｙ、Ａｒｇ、Ａｌａ、Ｇｌｕ、ＩＭＰ、甜菜碱等的含量发生显著的变化。这些成分可能对蒸煮后产生的特征特虾风味有较大的影响。     

Study of bioaccumulation of copper in liver and muscle of common carp Cyprinus carpio after copper sulfate bath

Common carp were exposed to two routine therapeutic concentrations of copper sulfate (10 mg/l in 1 h and 1 mg/l in 24 h). At different times after the copper sulfate bath (1, 2, 3, 7, 14 and 30 days), the copper concentrations in liver and muscle of carp was determined by means of an atomic absorption spectrophotometer. The results showed that the concentration of copper is significantly higher in liver than in muscle in all groups (p < 0.01). Concentrations of copper in liver and muscle in long-term bath groups were also significantly higher than short-term bath (p < 0.05). The concentration of copper in the livers of the control group was 174.2 ± 5.2 mg/kg. This value was significantly lower than the experimental groups even at 30 days after long-term baths (p < 0.01) but was not significantly higher than short-term bath (p > 0.05). The concentration of copper in the muscle of the control group was 22 ± 3.2 mg/kg, this value was significantly lower than for the short-term and long-term groups (p < 0.01). In livers, copper concentrations in short and long-term bath increased to an average of 281.6 ± 17.1 and 397.8 ± 31.2 mg/kg, respectively, by day 1 of treatment and then significantly declined to 189.8 ± 9.6 and 203.5 ± 8.9 mg/kg by 30 days post-treatment (p < 0.05). In muscles, copper concentrations in short-term bath increased from 39.1 ± 4.7 in first day of treatment to 50.8 ± 6.5 mg/kg in 30th day, but not significantly (p > 0.05), while in long-term bath it decreased significantly from 127 ± 13.6 to 43.2 ± 2.7 mg/kg (p < 0.05). This revised version was published online in August 2006 with corrections to the Cover Date.     

Effects of dietary vitamin E on muscle vitamin E and fatty acid content in Aohan fine-wool sheep

Background

Increasing the polyunsaturated fatty acid (PUFA) content and decreasing the saturated fatty acid (SFA) content of mutton can help to improve its nutritional value for consumers. Several laboratories have evaluated the effects of vitamin E on the fatty acid (FA) composition of muscle in sheep. However, little information is available on wool sheep, even though wool sheep breeds are an important source of mutton, especially in northern China where sheep are extensively farmed. The present study was designed to address the effects of vitamin E on muscle FA composition in male Aohan fine-wool sheep.

Methods

Forty-two male Aohan fine-wool lambs (5 mo old) with similar initial body weight were randomly divided into seven groups and fed diets supplemented with 0 (control group), 20, 100, 200, 1,000, 2,000, or 2,400 IU/sheep/d vitamin E for 12 mo. Three lambs from each group were slaughtered to measure vitamin E and FA content in the longissimus lumborum (LL) and gluteus medius (GM) muscles.

Results

Vitamin E concentrations in the LL and GM increased significantly after 12 mo of vitamin E supplementation (P < 0.05). However, this increase did not occur in a dose-dependent manner because the muscle vitamin E concentration was highest in the 200 IU/sheep/d group. Dietary vitamin E supplementation also caused a significant reduction in SFA content and an increase in monounsaturated FA (MUFA) content in the LL and GM (P < 0.05). All six doses of vitamin E significantly increased cis9 trans11-conjugated linoleic acid (c9t11-CLA) content in the LL compared with the control group (P < 0.05).

Conclusions

Dietary supplementation with vitamin E increased muscle vitamin E content and improved the nutritional value of mutton by decreasing SFA content and increasing MUFA and c9t11-CLA contents in Aohan fine-wool sheep. These effects were greatest in sheep fed a diet containing 200 IU/sheep/d vitamin E.