Effects of DHRS3 in C2C12 Myoblast Differentiation and Mouse Skeletal Muscle Injury

Myoblast differentiation is an essential process during skeletal muscle development. C2 C12 myoblast is a commonly used experimental model to study muscle cell differentiation in vitro. Dehydrogenase/reductase(SDR family) member 3(DHRS3) is a highly conserved member in short-chain alcohol dehydrogenase/reductase superfamily and has been shown to be involved in the metabolism of retinol. Previous experimental results showed that the expression of DHRS3 increased significantly during the differentiation of myoblasts differentiation. However, the effect of DHRS3 on mouse muscle cell differentiation was unclear. The objective of current study was to determine if DHRS3 affected muscle cell differentiation, and if DHRS3 was involved in muscle regeneration. Protein expression was determined by western blot and immunofluorescence analysis. The activation and inhibition of DHRS3 increased and decreased C2 C12 myoblast differentiation respectively, which indicated that DHRS3 could affect C2 C12 myoblast differentiation. DHRS3 expression was significantly changed during muscle regeneration, with the regeneration of muscle injury, the expression of DHRS3 tended to increase first and then decrease. It suggested that DHRS3 might be involved in muscle regeneration. In summary, this study confirmed the involvement of DHRS3 in C2 C12 myoblast differentiation and mouse skeletal muscle regeneration and provided a theoretical basis for further elucidating the molecular mechanism of muscle development.     

夹竹桃花挥发油的GC-MS分析及β-葡萄糖苷酶对夹竹桃花的增香和豚鼠离体子宫平滑肌的作用

目的:建立夹竹桃花挥发油GC-MS的色谱分离鉴定方法,分析夹竹桃花挥发油的化学成分和对豚鼠离体子宫平滑肌的作用。方法:采用挥发油提取器提取夹竹桃花挥发油,以GC-MS法进行分析鉴定,建立了豚鼠离体子宫模型。结果:分别从无酶和有酶的夹竹桃花挥发油提取物中确证了58和57个化合物,挥发油对豚鼠离体子宫平滑肌有收缩作用。结论:对夹竹桃的挥发油化学成分进行了比较分析结果表明,β-葡萄糖苷酶对夹竹桃花有较弱增香作用,也能增加豚鼠离体子宫平滑肌收缩。     

Real-time RT-qPCR assay to detect sequences in the Piscine orthoreovirus-1 genome segment S1 associated with heart and skeletal muscle inflammation in Atlantic salmon

During the last decade, Piscine orthoreovirus was identified as the main causative agent of heart and skeletal muscle inflammation (HSMI) in Atlantic Salmon, Norway. A recent study showed that PRV-1 sequences from salmonid collected in North Atlantic Pacific Coast (NAPC) grouped separately from the Norwegian sequences found in Atlantic Salmon diagnosed with HSMI. Currently, the routine assay used to screen for PRV-1 in NAPC water and worldwide cannot differentiate between the two groups of PRV-1. Therefore, this study aimed at developing a real-time polymerase chain reaction (RT-qPCR) assay to target the PRV-1 genome segments specific for variants associated with HSMI. The assay was optimized and tested against 71 tissue samples collected from different regions including Norway, Chile and both coast of Canada and different hosts farmed Atlantic Salmon, wild Coho Salmon and escaped Atlantic Salmon collected in British Columbia, West Coast of Canada. This assay has the potential to be used for screening salmonids and non-salmonids that may carry PRV-1 potentially causing HSMI.     

表观遗传修饰在骨骼肌细胞增殖分化过程中的研究进展

骨骼肌是肌肉的主要构成部分，骨骼肌细胞发生增殖和分化的过程都是肌肉发育的基础，直接影响着家养动物的产肉性能。研究发现表观遗传修饰作用对骨骼肌细胞增殖分化具有重要的调控作用，表明该遗传修饰作用对家养动物肌肉发育具有重大的意义。作者从DNA甲基化对骨骼肌细胞增殖分化影响、组蛋白乙酰化所含因子调控基因选择表达作用、非编码RNA调控和染色体重塑作用所起的影响等方面分别介绍了表观遗传在骨骼肌细胞增殖分化过程中的研究进展，简述了不同修饰方式和不同作用因子对骨骼肌增殖和分化两个过程的影响。同时也回顾了前人在研究骨骼肌增殖分化过程所用到的方法和手段，进而分析了表观调控作用因子在骨骼肌生长过程中所起到的作用。旨在进一步阐述表观遗传修饰在骨骼肌增殖和分化过程中所起到的重要作用，增强对骨骼肌增殖分化调控过程的了解，为和动物生产实际相结合提供参考途径，同时也为骨骼肌生长发育等分子调控提供更多参考素材。     

深水网箱和池塘养殖凡纳滨对虾肌肉营养成分的比较分析

对深水网箱和池塘养殖凡纳滨对虾(Litopenaeus vannamei)肌肉常规营养成分、氨基酸和脂肪酸质量分数进行了比较分析。结果显示:1)网箱养殖对虾肌肉粗蛋白质量分数显著高于池塘养殖(P0.05),而水分、粗脂肪和粗灰分质量分数无显著差异(P0.05);2)肌肉中检测到18种常见氨基酸,网箱养殖对虾肌肉氨基酸总量(TAA)、天门冬氨酸(Asp)、异亮氨酸(Ile)、精氨酸(Arg)和脯氨酸(Pro)质量分数显著高于池塘养殖(P0.05),而必需氨基酸(EAA)、半必需氨基酸(HEAA)、鲜味氨基酸(DAA)和虾味氨基酸(PFAA)两者无显著差异(P0.05);3)肌肉中检测到30种常见脂肪酸,两者的饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、多不饱和脂肪酸(PUFA)、n-3多不饱和脂肪酸(EPA和DHA)质量分数差异显著(P0.05),以网箱养殖对虾较高;两者的棕榈酸(C16∶0)质量分数最高,且网箱养殖对虾EPA+DHA质量分数是池塘养殖的1.90倍。结果表明,网箱养殖对虾营养成分要优于池塘养殖,具有较高的营养价值。     

Dietary fishmeal levels affect the volatile compounds in cooked muscle of farmed large yellow croaker Larimichthys crocea

A comparative study on the volatile compounds in cooked muscle of wild and farmed large yellow croaker (LYC) was conducted. The two farmed LYC groups were fed with diets containing 44% (CF) and 25% (LF) of fish meal (FM) respectively. Results showed that 48 volatiles, including aldehydes, alcohols, ketones, hydrocarbons, aromatics, acids, esters, furans and miscellaneous compound, were detected in cooked fillets. The LF group had significantly lower amounts of total aldehydes and ketones, higher content of miscellaneous compound in cooked fillets than that in the CF and wild groups (p < .05). Compared with the wild group, the LF group had significantly lower amounts of total alcohols, acids and esters, while the CF group had significantly lower amounts of total aldehydes, higher content of total ketones in cooked muscle (p < .05). According to the principal component analysis (PCA), some volatiles (propanal, nonanal, etc.) could be considered as sensitive indicators to classify cooked muscle samples. In conclusion, differences in the volatiles in the cooked muscle between the wild and farmed LYC have been found. Low level of dietary FM (25%) changed the volatile profiles in cooked fillets of farmed LYC. A PCA may be useful to screen potential volatiles to classify cooked muscle samples in this study.     

Effects of Dietary Lipids on the Growth Performance,Survival, and Digestive Enzymes of Juvenile Cuttlefish,Sepia lycidas

This study was conducted to determine the effects of dietary lipids on the growth performance, muscle composition, and enzyme activities of the stomach, intestines, and liver of Sepia lycidas juveniles. Fish oil and soybean lecithin were selected as lipid sources to formulate six experimental diets containing lipid levels of 3.68, 4.15, 6.62, 8.09, 9.56, and 11.03%. The feed efficiency first declined and then rose, with the lowest value obtained in individuals fed the 8.09% lipid content diet; the protein efficiency ratio significantly decreased with an increased lipid level. The highest crude protein content and lowest crude lipid content were simultaneously obtained in individuals fed the 9.56% lipid content diet. The activities of pepsase, trypsin, and intestine lipase initially increased before decreasing. The highest activities of protease, trypsin, and lipase were obtained in individuals fed the 9.56% lipid content diet, while the highest activity of amylase was obtained in individuals fed the 6.62% lipid content diet. Hepatic glutamate pyruvate transaminase and glutamic oxaloacetic transaminase initially increased and then held steady, with the highest activities simultaneously obtained in individuals fed the 9.56% lipid diet. Our results suggest that dietary lipids at a level of 9.56% could be the optimal lipid requirement for S. lycidas to grow and maintain normal metabolism.     

Gastrointestinal motility modulation by stress is associated with reduced smooth muscle contraction through specific transient receptor potential channel

Excessive stress response causes disability in social life. There are many diseases caused by stress, such as gastrointestinal motility disorders, depression, eating disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels underlie non-selective cation currents and are downstream effectors of G protein-coupled receptors. Ca²⁺ influx is important for smooth muscle contraction, which is responsible for gastrointestinal motility. Little is known about the possible involvement of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of this study was to measure the changes in gastrointestinal motility caused by stress and to elucidate the mechanism of these changes. The stress model used the water immersion restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was significantly reduced in the ileum of stressed mouse. Even under the conditions treated with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced contractions were all significantly reduced in the ileum of stressed mouse. Furthermore, the expression of TRPC3 was decreased in the ileum of stressed mouse. These results suggest that the gastrointestinal motility disorders due to stress is associated with specific non-selective cation channel.     

Amino acid absorption and protein synthesis responses of turbot Scophthalmus maximus to lysine and leucine in free,dipeptide and tripeptide forms

The study aimed to investigate the effects of crystalline Lys and Leu, Lys‐Leu dipeptide and Lys‐Leu‐Lys/Leu‐Lys‐Leu tripeptide, on growth, postprandial Lys and Leu concentrations, gene expression of peptide and amino acid (AA) transporters and related gene expression of protein synthesis pathway in turbot. Three diets (CAA, Di and Tri) contained Lys and Leu as free (Lys and Leu), dipeptide (Lys‐Leu) and tripeptide (Lys‐Leu‐Lys/Leu‐Lys‐Leu) forms, respectively. Improved growth was observed in the Di group compared with the CAA group. For peptide and AAs transporters, PepT1, B⁰AT1 and y⁺LAT2 mRNA levels were affected in proximal intestine by dietary treatments. Free Lys and Leu concentrations in the CAA group were significantly higher than that of the Di and Tri groups at 6 hr postfeeding in serum and at 2, 6 and 24 hr postfeeding in muscle. For protein synthesis pathway in muscle, Akt2, TOR and S6k1 gene expression were the highest in the Di group and the lowest in the CAA group, whereas MuRF1 relative expression was the highest in the Tri group. In conclusion, dietary Lys‐Leu dipeptide was utilized more efficiently than free Lys and Leu or Lys‐Leu‐Lys/Leu‐Lys‐Leu tripeptide for turbot by regulating AAs transport, postprandial AAs concentration and the synthesis of muscle proteins.