卵丘细胞对牛体外受精效果的影响

[目的]探索卵丘细胞对牛体外成熟卵母细胞体外受精效果的影响.[方法]试验采用体外成熟后卵母细胞脱除卵丘细胞组、部分脱除组及不脱除组.[结果]与卵丘细胞共培养时,部分脱除组的卵裂率及囊胚率(74.4％±4.1、53.7％±5.1)好于不脱除组(72.7％ ±5.1、52.4％±3.5),差异不显著(P＞0.05)、两者都好于全部脱除组(39.6％±4.5、l8.8％±4.6),差异显著(P＜0.05),且都显著优于对照组.卵丘细胞与褪黑素两者联合使用时,效果最佳.部分脱除组的卵裂率及囊胚率(79.8％±3.7、56.5％±5.1)好于不脱除组(78.2％±2.6、55.8％±4.6),差异不显著,两者都好于完全脱除组(48.3％±5.5、22.7％±4.3)及对照组,且差异显著(P＜0.05).[结论]该研究对奶牛和肉牛的生产提供了技术支持.     

水分胁迫下外源褪黑素对大豆苗期抗氧化特性和产量的影响

为探究大豆苗期干旱外源褪黑素对其抗氧化性和产量的影响,以干旱敏感型大豆品种绥农26为试验材料,分析水分胁迫下叶面喷施和根施褪黑素对大豆叶片和根系抗氧化酶(SOD、POD、CAT)活性和丙二醛(MDA)含量以及产量的影响。结果表明:与水分胁迫(CK)相比,施用褪黑素显著提高大豆叶片抗氧化酶活性,处理后第4天,叶面喷施和根施处理与CK相比,SOD活性在V5期分别提高6.3%和19.5%,POD、CAT活性在V1期分别提高7.5%、12.7%和5.6%、9.9%(P<0.05),MDA含量在V3期分别降低了9.4%、10.3%(P<0.05);处理后第7天,叶面喷施褪黑素与对照相比,在V1期SOD、POD、CAT活性分别提高了6.3%、9.5%、4.9%(P<0.05),而根施褪黑素处理较对照分别提高了6.9%、20.9%、11.1%(P<0.05),MDA含量叶面喷施和根施褪黑素处理与CK相比分别降低了6.9%、10.3%(P<0.05);V1、V3和V5期叶面喷施褪黑素处理的产量与CK相比分别提高了31.6%、29.8%、12.6%(P<0.05),而根施褪黑素处理的产量较对照分别提高了43.3%、31.8%、24.9%(P<0.05)。结果表明:外源褪黑素通过降低MDA含量,提高抗氧化酶活性、维持细胞水分平衡、提高大豆的抗旱能力,最终提高其产量,而且根施褪黑素效果要显著优于叶施。     

三种浸种剂对Na2SO4胁迫下小麦种子萌发期耐盐性的影响

为了解黄腐酸、褪黑素、水杨酸三种浸种剂对硫酸盐胁迫下小麦种子萌发期耐盐性的调节效应,分别采用不同浓度的黄腐酸(0.5、1.0和1.5 g·L^-1)、褪黑素(0.01、0.05和0.10 mmol·L^-1)、水杨酸(0.1、0.5和1.0 mmol·L^-1)对小麦进行浸种处理,随后与未处理的小麦种子一并采用100 mmol·L^-1 Na₂SO₄溶液培养,测定各处理下小麦种子萌发期的生长生理指标,并通过主成分分析综合评价其耐盐性。结果表明,0.5～1.5 g·L^-1的黄腐酸、0.01～0.10 mmol·L^-1褪黑素、0.1～0.5 mmol·L^-1水杨酸浸种均提升了小麦根系活力、体内抗氧化酶活性,降低了小麦体内超氧阴离子自由基■产生速率及丙二醛(MDA)含量,缓解了盐分对小麦种子萌发的胁迫程度,增强了小麦种子萌发期的耐盐性,促进了小麦的萌发生长。其中,1.5 g·L^-1的...     

褪黑素对大头菜幼苗生长及镉积累的影响

通过盆栽试验,研究了Cd污染条件下,不同浓度褪黑素喷施对大头菜幼苗生长及Cd积累的影响。结果表明,浓度50、100和150μmol/L的褪黑素增加了大头菜幼苗的根长、根系体积、株高、块根直径和块根长度,也增加了其根系、块根、地上部分及可食用部分的生物量,而浓度为200μmol/L的褪黑素则降低了大头菜幼苗的这些指标。不同浓度的褪黑素处理均提高了大头菜幼苗的光合色素(叶绿素a、叶绿素b、叶绿素总量及类胡萝卜素)含量及抗氧化酶(SOD、POD和CAT)活性,并降低了大头菜幼苗根系、块根、地上部分和可食用部分的Cd含量。随着褪黑素浓度的增加,大头菜幼苗各器官的Cd含量呈降低的趋势。因此,喷施褪黑素能够促进大头菜幼苗生长,降低其对Cd的积累。     

不同光照制度对奶牛褪黑素分泌的影响

本试验旨在研究不同光照制度对奶牛褪黑素分泌的影响,选用10头胎次、泌乳阶段相近(120±40)d的荷斯坦奶牛,分别采用16 h光照8 h黑暗、8 h光照16 h黑暗2种光照制度对其实行光控管理,于试验处理前2 d和试验第1、6、11、16、21、26、31天采集23:00血样和05:00、17:00奶样,其中05:00...     

褪黑激素在动物生产上的研究进展

褪黑激素是一种在多个物种的多个组织中广泛存在并具有重要生理作用的激素.本文主要对褪黑激素(MLT)的昼夜分泌规律及调控、合成代谢以及目前在动物生产各个方面的研究进展作了概述.     

光照对黑青稞萌发过程中褪黑素、酚类物质含量和抗氧化活性的影响

为研究光照对青稞萌发过程中功能成分的影响,以隆子黑青稞为材料,采用酶联免疫吸附法和分光光度计法测定了不同光照时间处理下黑青稞萌发过程中褪黑素、总酚和总黄酮含量及其抗氧化活性;同时测定了黑青稞发芽率、胚根和胚芽长度,并对避光萌发5 d的芽苗进行了感官评定。结果表明,随萌发时间的延长,青稞芽苗中褪黑素、总酚和总黄酮含量与种子相比均显著增加,且不同光照时间下芽苗中各被测指标增幅有显著性差异。避光条件下萌发5 d时芽苗的褪黑素含量最高,为13.11 ng·g^-1 ,是种子的2.2倍;避光萌发第7天时芽苗中总酚和总黄酮含量最高,分别为842.81±3.33和157.31±0.53 mg·100 g^-1,是种子的2.8倍和3.9倍。抗氧化活性因为测定方法的不同略有差异,但不同光照时间均增加了种子抗氧化活性,避光萌发第7天,芽苗中FRAP、DPPH自由基和ABTS自由基清除能力最大,分别是种子的3.2倍、4.9倍和  4.6倍;羟自由基清除能力在避光萌发第5天达到最大,是种子的8.0倍。黑青稞发芽率和胚芽长不受光照时间的影响,避光处理下胚根平均长度最长;避光萌发5 d的黑青稞芽苗感官评定整体可接受性为7级-中等喜欢。综上,避光萌发显著增加了黑青稞活性成分含量和抗氧化活性,为黑青稞相关功能产品的开发提供了数据支撑和理论参考。     

Effects of orexigenic peptides and leptin on melatonin secretion during different photoperiods in seasonal breeding ewes: an in vitro study

The pineal gland (PG) acts as a neuroendocrine transducer of daily and seasonal time through the nocturnal release of melatonin. Here, we examined the interaction of season, orexin, ghrelin, and leptin on melatonin secretion by pineal explants in short-term culture. Glands were collected after sunset from 12 ewes during long days (LD; April and May) and from an additional 12 ewes during short days (SD; October and November). Glands were transected sagittally into strips, with each equilibrated in 2.5 mL of Dulbecco's modified Eagle's medium for 60 min, followed by a 2-h incubation in control medium or medium containing orexin B (10 and 100 ng/mL), ghrelin (10 and 100 ng/mL), or 50 ng/mL of leptin. After a 3-h incubation, some PG explants treated previously with lower doses of orexin or ghrelin were challenged with 50 ng/mL of leptin and those treated with both doses of orexin were challenged with 300 nM of the β-agonist isoproterenol. One milliliter of medium was harvested and replaced from each well every 30 min. Treatment with the low dose of orexin during LD increased melatonin secretion about 110% (P<0.01); treatment with a high dose increased melatonin secretion about 47% (P<0.001). During the SD period, leptin stimulated (P < 0.05) melatonin secretion slightly compared with mean melatonin concentration in controls. However, together, orexin and leptin depressed (P<0.01) melatonin secretion. Both doses of ghrelin reduced (P < 0.01) melatonin concentration during the SD season compared with control culture. Addition of ghrelin and leptin to culture medium increased (P<0.01) melatonin concentration compared with ghrelin-treated culture and decreased melatonin concentration (P<0.01) compared with leptin-treated culture during SD. Isoproterenol stimulated (P<0.01) melatonin secretion compared with values observed during the pretreatment period. We conclude that orexigenic peptides (orexin B and ghrelin) and an anorectic peptide (leptin) affect PG directly. The responses of PG to those hormones depend on day length. Moreover, secretion of melatonin from the ovine PG is under an adrenergic regulation.     

Melatonin mitigates the adverse effect of hypoxia during myocardial differentiation in mouse embryonic stem cells

BackgroundHypoxia causes oxidative stress and affects cardiovascular function and the programming of cardiovascular disease. Melatonin promotes antioxidant enzymes such as superoxide dismutase, glutathione reductase, glutathione peroxidase, and catalase.ObjectivesThis study aims to investigate the correlation between melatonin and hypoxia induction in cardiomyocytes differentiation.MethodsMouse embryonic stem cells (mESCs) were induced to myocardial differentiation. To demonstrate the influence of melatonin under hypoxia, mESC was pretreated with melatonin and then cultured in hypoxic condition. The cardiac beating ratio of the mESC-derived cardiomyocytes, mRNA and protein expression levels were investigated.ResultsUnder hypoxic condition, the mRNA expression of cardiac-lineage markers (Brachyury, Tbx20, and cTn1) and melatonin receptor (Mtnr1a) was reduced. The mRNA expression of cTn1 and the beating ratio of mESCs increased when melatonin was treated simultaneously with hypoxia, compared to when only exposed to hypoxia. Hypoxia-inducible factor (HIF)-1α protein decreased with melatonin treatment under hypoxia, and Mtnr1a mRNA expression increased. When the cells were exposed to hypoxia with melatonin treatment, the protein expressions of phospho-extracellular signal-related kinase (p-ERK) and Bcl-2-associated X proteins (Bax) decreased, however, the levels of phospho-protein kinase B (p-Akt), phosphatidylinositol 3-kinase (PI3K), B-cell lymphoma 2 (Bcl-2) proteins, and antioxidant enzymes including Cu/Zn-SOD, Mn-SOD, and catalase were increased. Competitive melatonin receptor antagonist luzindole blocked the melatonin-induced effects.ConclusionsThis study demonstrates that hypoxia inhibits cardiomyocytes differentiation and melatonin partially mitigates the adverse effect of hypoxia in myocardial differentiation by regulating apoptosis and oxidative stress through the p-AKT and PI3K pathway.