Methyl dynamics of the amyloid-beta peptides Abeta40 and Abeta42

To probe the role of side chain dynamics in Abeta aggregation, we studied the methyl dynamics of native Abeta40 and Abeta42 by measuring cross relaxation rates with interleaved data collection. The methyl groups in the C-terminus are in general more rigid in Abeta42 than in Abeta40, consistent with previous results from backbone (15)N dynamics. This lends support to the hypothesis that a rigid C-terminus in Abeta42 may serve as an internal aggregation seed. Interestingly, two methyl groups of V18 located in the central hydrophobic cluster are more mobile in Abeta42 than in Abeta40, most likely due to the paucity of V18 intra-molecular interactions in Abeta42. V18 may then be more available for inter-molecular interactions to form Abeta42 aggregates. Thus, the side chain mobility of the central hydrophobic cluster may play an important role in Abeta aggregation and may contribute to the difference in aggregation propensity between Abeta40 and Abeta42.     

Effects of dietary 25-hydroxyvitamin D3 supplementation on growth performance,immune function and antioxidative capacity in weaned piglets

The study evaluated the effects of different doses of 25-hydroxyvitamin D₃ (25(OH)D₃) on growth performance, immune function and antioxidative capacity in piglets. In a 21-d trial, 35 weaned pigs were divided into five groups and diets were supplemented with 5.5 (control), 43.0, 80.5, 118.0 and 155.5 μg 25(OH)D₃/kg, respectively. No treatment effects were observed for average daily gain, average daily feed intake and feed to gain ratio. Increasing dietary 25(OH)D₃ levels increased serum 25(OH)D₃ concentrations linearly (p < 0.01), decreased the frequency of CD3+CD4+ and CD3+CD8+ T cells (p < 0.01), and the serum level of complement component 3 (p < 0.05). Supplementation of 80.5 and 118.0 μg 25(OH)D₃/kg enhanced the activity of serum glutathione peroxidase (p < 0.05) and addition of 43.0 μg 25(OH)D₃/kg increased the malondialdehyde concentration (p < 0.05). Overall, feeding high-dose 25(OH)D₃ to weaned pigs partly improved immune functions and the antioxidative capacity.     

湘黔桂交界地区种子植物区系与邻近区系关系的定量研究

湘黔桂地区与邻近地区种子植物区系各分类等级相似系数为：科的相似系数由大到小依次是南岭、华中、华东、滇黔桂、岭南;属的相似系数依次是华东、南岭、滇黔桂、岭南、华中;种的相似系数依次是岭南、滇黔桂、华中、华东、南岭。科、属、种的相似系数次序不一致的原因可能有三个方面：（1）各比较地区的面积大小不一,在计算相似系数时又没有进行等效面积转换;（2）对各个地区植物资源调查的深浅程度不一;（3）不同分类等级的相似系数在说明区系关系时,其重要性不一样,这可能是重要的原因。在一定范围内的区系比较研究中,种的相似系数能够较好地说明植物区系之间的关系。湘黔桂交界地区与邻近地区种子植物属的地理成分的定量关系是：华中与华东区系以及岭南与滇黔桂区系有密切的关系,而湘黔桂与南岭区系亦密切相关、属的地理成分的树状图表明：湘黔桂与南岭区系有密切的关系,而月,岭南和滇黔桂区系与湘黔桂区系的关系比华巾和华东区系与湘黔桂区系的关系要密切得多,达2倍以上。这些结果与上述各分类等级的相似系数,尤其是种的相似系数的结果相差较大,主要是因为这里指的是属的地理成分之间的定量关系,而非其他等级的相似性。     

High nutrient intake during the early postnatal period accelerates skeletal muscle fiber growth and maturity in intrauterine growth-restricted pigs

Background

Intrauterine growth-restricted (IUGR) neonates impair postnatal skeletal muscle growth. The aim of this study was to investigate whether high nutrient intake (HNI) during the suckling period could improve muscle growth and metabolic status of IUGR pigs.

Methods

Twelve pairs of IUGR and normal birth weight (NBW) pigs (7 days old) were randomly assigned to adequate nutrient intake and HNI formula milk groups. Psoas major (PM) muscle sample was obtained after 21 days of rearing.

Results

IUGR decreased cross-sectional areas (CSA) and myofiber numbers, activity of lactate dehydrogenase (LDH), and mRNA expression of insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), mammalian target of rapamycin (mTOR), ribosomal protein s6 (RPS6), eukaryotic translation initiation factor 4E (eIF4E), protein expression of phosphorylated mTOR (P-mTOR), and phosphorylated protein kinase B (P-Akt) in the PM muscle of pigs. Irrespective of birth weight, HNI increased muscle weight and CSA, the concentration of RNA, and ratio of RNA to DNA, as well as ratio of LDH to β-hydroxy-acyl-CoA-dehydrogenase in the PM muscle of pigs. Furthermore, HNI increased percentages of MyHC IIb, mRNA expression of IGF-1, IGF-1R, Akt, mTOR, RPS6, and eIF4E, as well as protein expression of P-mTOR, P-Akt, P-RPS6, and P-eIF4E in the PM muscle of pigs.

Conclusion

The present findings suggest that high nutrient intake during the suckling period could improve skeletal muscle growth and maturity, which is associated with increasing the expression of protein deposition-related genes and accelerating the development of glycolytic-type myofiber in pigs.

     

Dietary Sodium Butyrate Supplementation Promotes Oxidative Fiber Formation in Mice

Sodium butyrate (SB), a sodium salt of butyric acid, has been shown to improve the animal production performance. The aim of this work was to test the effect of feeding mice with diets containing different dose of SB (1, 3, and 5%) on oxidative fiber formation. Dietary SB supplementation had no effect on body weights and food intakes. Dietary SB supplementation upregulated the expressions of oxidative fiber-related protein including MyHC I, MyHC IIa, myoglobin, and troponin-I-slow. Dietary SB supplementation also upregulated the expressions of phospho-FoxO1 and MEF2C protein, but did not affect total FoxO1 protein expression. Taken together, these results indicate that dietary SB supplementation promotes oxidative fiber formation in mice, which might be through inactivation of FoxO1 and upregulation of MEF2C expression.     

Characterization of an artificial dimer of ribonuclease H using 1H NMR spectroscopy

Summary The protein fusion technique was applied in the synthesis of an artificial dimer of ribonuclease H (305 residues). ¹H NMR spectroscopy was used to analyze the structure of this dimer. Spectral profiles and pK_a values of the histidine residues obtained using ¹H NMR indicate that the dimer retains the secondary and tertiary structures of the intact monomer. Selective spin-lattice relaxation measurements suggest that the two monomeric units in the dimer are in tight contact. Furthermore, the 2D ¹H NMR and paramagnetic relaxation filter results show that the two monomers bind together through interactions between the N- and C-terminal sites of the linked regions.     

Effects of dietary amylose and amylopectin ratio on growth performance,meat quality,postmortem glycolysis and muscle fibre type transformation of finishing pigs

The present study was conducted to investigate the effects of dietary amylose and amylopectin ratio on growth performance, meat quality, postmortem glycolysis and muscle fibre type transformation of finishing pigs. Twenty-four barrows (Duroc × Landrace × Yorkshire) with an average initial body weight of 61.7 ± 2.01 kg were randomly assigned to four dietary treatments with amylose: amylopectin ratios of 1:1 (HD), 1:2 (MD), 1:3 (CD) and 1:4 (LD). The results showed that the average daily weight gain of finishing pigs tended to reduce with the ratio of amylose and amylopectin decreased (p = 0.09). Diet LD increased the pH_24h value and decreased the shear force in longissimus dorsi (LM) compared with diet HD (p < 0.05). Diet LD decreased the lactate content and the HK-2 mRNA abundance and increased the mRNA abundance of ATP5B in LM compared with diet HD (p < 0.05). Higher mRNA abundance of MyHC I and lesser abundance of MyHC IIb in LM were found in pigs fed diet CD and LD than those fed diet HD (p < 0.05). Furthermore, pigs fed diet LD had higher mRNA abundances of PGC-1α and PPAR δ in LM than other groups (p < 0.05). These results suggested that diet with low amylose and amylopectin ratio could improve meat quality of finishing pigs via delaying muscle glycolysis capacity and shifting muscle fibre types.