Arginine promotes myogenic differentiation and myotube formation through the elevation of cytoplasmic calcium concentration

This study aimed to explore the mechanism underlying arginine-promoted myogenesis of myoblasts. C2C12 cells were cultured with a medium containing 0.1, 0.4, 0.8, or 1.2 mmol/L arginine, respectively. Cell proliferation, viability, differentiation indexes, cytoplasmic Ca²⁺ concentration, and relative mRNA expression levels of myogenic regulatory factors (MRF) and key Ca²⁺ channels were measured in the absence or presence of 2 chemical inhibitors, dantrolene (DAN, 10 μmol/L) and nisoldipine (NIS, 10 μmol/L), respectively. Results demonstrated that arginine promoted myogenic differentiation and myotube formation. Compared with the control (0.4 mmol/L arginine), 1.2 mmol/L arginine upregulated the relative mRNA expression levels of myogenin (MyoG) and Myomaker at d 2 during myogenic induction (P < 0.05). Cytoplasmic Ca²⁺ concentrations were significantly elevated by arginine supplementation at d 2 and 4 (P < 0.05). Relative mRNA expression levels of Ca²⁺ channels including the type 1 ryanodine receptor (RyR1) and voltage-gated Ca²⁺ channel (Cav1.1) were upregulated by 1.2 mmol/L arginine during 2-d myogenic induction (P < 0.01). However, arginine-promoted myogenic potential of myoblasts was remarkably compromised by DAN and NIS, respectively (P < 0.05). These findings evidenced that the supplementation of arginine promoted myogenic differentiation and myotube formation through increasing cytoplasmic Ca²⁺ concentration from both extracellular and sarcoplasmic reticulum Ca²⁺.     

外源施钙对加工番茄果实硬度及品质相关指标的影响

【目的】明确外源钙对加工番茄果实硬度及品质的影响。【方法】以加工番茄品种"里格尔87-5"和"石红12"为材料,在果实发育期定期叶面喷施不同浓度CaCl2溶液,分析成熟果实的硬度及品质指标与施钙的关系。【结果】与CK(0 g/L)相比,对于品种"里格尔87-5"而言,2,4,8 g/L的CaCl2处理分别可使果实产量增加9.2%,39.6%和14.2%,果实硬度增加9.34%,5.09%和5.01%,PG酶活性降低21.08%,17.73%和14.89%,可溶性固性物含量增加12.57%,9.16%和8.64%,番茄红素含量增加42.86%,42.86%和38.86%;2和4 g/L CaCl2处理使有机酸含量分别增加32.29%和12.11%;2 g/L CaCl2处理使果实还原糖、总糖、Vc含量和果实耐压力分别增加10.57%,22.10%,10.24%和11.50%。对于品种"石红12"而言,2,4,8 g/L CaCl2处理分别使产量增加58.6%,38.0%和30.8%,可溶性固性物含量增加20.62%,15.83%和14.39%,番茄红素含量增加81.16%,150%和18.84%,PG酶活性降低21.01%,43.19%和8.84%;2和4 g/L CaCl2处理分别使果实硬度增加3.10%和0.07%;2 g/L CaCl2处理使果实还原糖、总糖、Vc、有机酸含量和果实耐压力分别增加10.34%,8.30%,11.88%,1.44%和8.81%。【结论】叶面喷施2 g/L CaCl2,是提高供试2个加工番茄品种产量和品质及增加果实硬度和耐压力的适宜质量浓度。     

Antioxidant,Anti-Nephrolithe Activities and in Vitro Digestibility Studies of Three Different Cyanobacterial Pigment Extracts

Phycobiliprotein-containing water and carotenoid-containing methanolic extracts of three different cyanobacteria, Pseudanabaena sp., Spirulina sp. and Lyngbya sp., were studied for their DPPH scavenging, iso-bolographic studies, and anti-nephrolithe activities. The best EC₅₀ values for DPPH scavenging were in Lyngbya water (LW, 18.78 ± 1.57 mg·mg⁻¹ DPPH) and Lyngbya methanol (LM, 59.56 ± 37.38 mg·mg⁻¹ DPPH) extracts. Iso-bolographic analysis revealed most of the combinations of extracts were antagonistic to each other, although LM—Spirulina methanol (SM) 1:1 had the highest synergistic rate of 86.65%. In vitro digestion studies showed that DPPH scavenging activity was considerably decreased in all extracts except for Pseudanabaena methanol (PM) and LM after the simulated digestion. All of the extracts were effective in reducing the calcium oxalate crystal size by nearly 60%–65% compared to negative control, while PM and Spirulina water (SW) extracts could inhibit both nucleation and aggregation of calcium oxalate by nearly 60%–80%.     

钙化条件对海藻酸钙膜钙含量和拉伸强度的影响

采用不同钙源制备海藻酸钙膜,根据膜的钙含量和拉伸强度确定了钙源的种类、钙化温度、钙化时间和钙化浓度。结果表明,在钙源选择氯化钙,钙化溶液的温度选择40℃,钙化时间选择20 min,钙化质量分数选择3%时,得到的海藻酸钙膜的钙含量最多、拉伸强度最大,并且膜拉伸强度的变化趋势与钙含量变化趋势基本一致。     

有机钾肥和钾硅钙矿物肥对烤烟生长及烟叶产量质量的影响

为了探讨有机钾肥和矿物钾肥在河南省烤烟上的施用效果,采用大田试验,研究了施用有机钾肥、钾硅钙矿物肥替代15%硫酸钾对烤烟生长及烟叶产量、质量的影响。结果表明,施用有机钾肥、钾硅钙矿物肥替代15%硫酸钾处理比全部施用硫酸钾处理显著提高了圆顶期叶片SPAD值,起到了延缓叶片衰老,保证叶片有足够成熟时间的作用;与全部施用硫酸钾处理相比,用有机钾肥、粒状钾硅钙矿物肥、粉状钾硅钙矿物肥替代15%硫酸钾的3个处理,烟叶产量分别提高16.4%、21.1%和13.0%,产值分别增加5 037.3、10 975.0和3 306.6元/hm2。施用有机钾肥、粉状和粒状钾硅钙矿物肥的3个处理间相比,烟叶产量差异不显著,烟叶产值以施用粒状钾硅钙矿物肥替代15%硫酸钾处理最高,上、中、下部烟叶钾含量显著提高,下部叶和中部叶钾氯比达3.5以上。     

肉鸡腹水症对组织钙磷分布及钙磷利用率的影响

本试验研究了肉鸡腹水症(PHS)对组织钙磷分布及饲料钙磷利用率的影响。120只1日龄艾维茵(AA)肉鸡随机分成2组,即对照组和试验组,每组6个重复,每个重复10只鸡。试验组采用低温(LAT)和饲粮添加三碘甲腺原氨酸(T3,1.5mg/kg)诱导产生腹水症。试验期为21d。试验结果表明:1)14日龄时,试验组肉鸡的心脏、肝脏、十二指肠中钙含量与对照组相比,有增加趋势,胫骨、血清钙有下降趋势,但差异均不显著(P>0.05)。试验组肉鸡的心脏磷含量极显著低于对照组(P<0.01),十二指肠磷含量显著高于对照组(P<0.05)。饲料中钙磷利用率,试验组极显著低于对照组(P<0.01)。2)21日龄时,试验组肉鸡的心脏、肝脏中的钙含量显著高于对照组(P<0.05)。十二指肠、胫骨、血清中的钙含量两组间无显著差异(P>0.05)。十二指肠、血清磷含量试验组显著高于对照组(P<0.05),其余组织磷含量两组间无显著差异(P>0.05)。饲料中钙磷利用率,试验组极显著低于对照组(P<0.01)。3)血清碱性磷酸酶含量14、21日龄试验组和对照组差异均不显著(P>0.05)。     

日粮磷对产蛋鸡组织钙的影响

选择４８只１７８日龄健康的罗曼商品蛋鸡，随机分成４个组，分别锔喂含有效磷为０．０８％，０．１２％，０．１５％和０．２５％的日粮，试验期６０d。结果表明，试验至第１５，３０和４５d，低磷日粮显著降低全血、血浆、蛋黄钙含量。第３０d低磷日粮显著降低羽毛、肝脏、脾脏、心脏、肺脏、肾脏和肌肉钙含量。第６０d，低磷日粮显著降低血浆、肺脏、肌肉钙含量。日粮磷水平与血浆、全血、羽毛、蛋黄、肌肉钙含量呈极显著正相关，与肝脏、肺脏钙含量呈显著正相关，表明低磷日粮对钙的代谢产生不利影响。     

沈阳市某乳业公司奶牛钙、磷、β-胡萝卜素盈缺状况检查

对沈阳市某乳业公司七个奶牛场牛群血中钙、磷、β-胡萝卜素含量进行抽检，从全群3，000多头成母牛中共抽检350头奶牛，其中包括84头高产奶牛、77头干奶牛、92头产后牛和97头有病牛。结果表明：全群牛血中钙、磷的平均含量偏低，血钙的最高值、平均值和最低值分别为3．32mmol／l、2．26 0．44mmol／l和1．53mmol／l，血磷的最高值、平均值和最低值分别为2．71mmol／l、1．72 0．51mmol／l和0．84mmol／l；血中钙、磷比例不当，其最大值、平均值和最小值分别为3．96：1．0、1．70：1．0和0．645：1．0：血中钙、磷含量乘积偏低，其最高值、平均值和最低值分别为63．74、48．20和24．50；血中β-胡萝卜素含量不足，其最高值、平均值和最低值分别为657μg／100ml、278．69 201.78μg／100ml和52μg／100ml，其中高产牛血中含量相对较高。