Effects of three methionine sources in diets on temporal B0AT1 and ASCT2 mRNA expression in different intestinal segments of cobia,Rachycentron canadum

A 4‐week feeding trial was conducted using five groups of hybrid grouper (61.15 ± 0.15 g) to explore the potential effects of three methionine (Met) sources. Five isonitrogenous and isolipidic diets were formulated that included a fishmeal (FM) diet; nonsupplemented (NS) diet; or NS diets with the addition of the L‐methionine (L‐Met), DL‐methionine (DL‐Met), or coated Met (Co‐Met) to obtain the same Met level as the FM diet. Fish were randomly distributed into sea cages (30 fish per cage). Weight gain and specific growth rate in the DL‐Met group and FM group were significantly higher than those in all other groups (p < .05). In the proximal and distal intestines, of the 20 gene and time combinations (10 per gene), there were 14 combinations (70%) in which there were no significant differences in gene expression levels between the FM and DL‐Met groups (p > .05). The main reason for the same growth effect between the DL‐Met and FM groups may be attributed to the synchronized absorption at most time points after feeding, which had similar expression patterns of B⁰AT1 and ASCT2 of the proximal and distal intestines between two groups.     

Comparison of morphology, viability, and function between blood and milk neutrophils from peak lactating goats

The morphological features of blood and milk neutrophils from peak lactating goats were compared using light microscopy, scanning electron microscopy and flow cytometry in order to investigate the cytological changes of neutrophils after migration into the mammary gland. The kinetics of reactive oxygen intermediates (ROI) generation and gelatinase release of blood and milk neutrophils, with or without stimulation of phorbol 12-myristate, 13-acetate ester (PMA), were used to characterize their responses to inflammatory stimuli. Neutrophils isolated from goat milk were highly segmented and contained multi-lobed nuclei. Ultrastructurally, milk neutrophils were more ruffled on the surface compared to blood neutrophils. Approximately 30% of milk neutrophils were undergoing cell death, either necrosis or apoptosis, in contrast to 8% of blood neutrophils. The ROI production of activated milk neutrophils peaked earlier than blood neutrophils, but the duration and the intensity were much less. Neutrophils from both sources augmented the release of gelatinase in response to PMA (1 ng/mL). However, the amount of gelatinase released from milk neutrophils was lower (P < 0.05) than that of blood neutrophils. In summary, more neutrophils become apoptotic and necrotic in the mammary gland, presumably due to spontaneous aging, the process of diapedesis, and the interaction with milk components. Milk neutrophils have impaired functionalities in comparison with blood neutrophils. The information is relevant when studying mammary gland immunity and related diseases, such as mastitis.     

亚热带牧用草地中威提特东非狼尾草的种子繁殖研究

在3月和4月对全日制放牧的东非狼尾草草地上的风干牛粪取样,进行发芽试验,分别测定其中的东非狼尾草发芽种子数量。结果,3月取样平均432.5 g的牛粪中东非狼尾草平均发芽种子数量为118.25粒,4月取样平均437.8 g的牛粪中东非狼尾草平均发芽种子数量为52.8粒,二者平均牛粪重为435.15 g,平均发芽种子为85.5粒,说明牛粪中东非狼尾草种子数量较多,是其繁殖扩展较快的主要原因;3月取样的种子数量为4月取样数量的1.38倍,说明人工利用牛粪进行东非狼尾草繁殖时,需在有降雨来临前准备,即1～3月进行牛粪的准备工作。     

苦瓜转录因子McEIL2的克隆及其表达分析

本研究从已构建的苦瓜果实均一化文库筛选得到一个EIN3-like同源EST序列,结合RACE技术,克隆得到EIN3基因c DNA全长序列,命名为Mc EIL2(Gen Bank登录号:KF595122)。该基因全长2 122 bp,开放阅读框1 890 bp,编码629个氨基酸,预测该蛋白的分子量为71.58 k D,与黄瓜Cus EIN3、甜瓜Cm EIL1、苜蓿Mt EIL1、绿豆Vr EIL1和番茄Le EIL1的蛋白同源性分别为89.61%、78.37%、71.23%、69.09%和65.66%。Mc EIL2基因的编码蛋白亚细胞定位于细胞核,荧光定量分析表明Mc EIL2基因表达量在幼果期先强后弱,绿熟期最低,破色期表达量大幅增加至最高随后下降,推测该基因参与苦瓜果实成熟软化调控过程。本研究初步明确了Mc EIL2基因在苦瓜成熟过程表达模式,可为今后进一步揭示苦瓜果实成熟软化的分子机制奠定基础。     

Effects of intrauterine growth restriction during late pregnancy on the ovine fetal renal function and antioxidant capacity

This study investigated the effects of intrauterine growth restriction during late pregnancy on the ovine fetal renal function and renal antioxidant capacity. Eighteen ewes pregnant were randomly divided into control group (CG, ad libitum, 0.67 MJ ME·BW^−0.75·day⁻¹, n = 6), restricted group 1 (RG1, 0.18 MJ ME·BW^−0.75·day⁻¹, n = 6), and restricted group 2 (RG2, 0.33 MJ ME·BW^−0.75·day⁻¹, n = 6). At 140 days, the fetal blood, allantoic fluid and kidney tissue were collected to determinate fetal renal function and renal antioxidant capacity. The results showed that the fetal weight, kidney weight, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), aquaporin-2 (AQP-2) and aquaporin-3 (AQP-3), and total antioxidant capacity (T-AOC) in RG1 group were decreased compared with the CG (P < 0.05), but the contents of β2-Microglobulin (β 2-MG), cystatin C (Cys-C), filtered sodium excretion fraction (FENa), malondialdehyde (MDA), and hydroxyl radical (OH) in RG1 group were increased (P < 0.05). The impaired ovine fetal renal growth, antioxidant imbalance and dysfunction of glomerulus ultrafiltration, and the renal tubules reabsorption were induced by maternal malnutrition during late pregnancy.     

制度有效性检验:基于实验经济学的一个综述

长期以来，制度有效性的检验问题一直制约着制度经济学的发展，而近期实验经济学中大量的机制设计实验为其提供了一种新的检验手段。通过实验经济学中公共物品自愿捐赠机制对有关正式制度与非正式制度的比较研究，同时梳理相应文献，其文献大致可分为两类：外生制度静态比较与内生制度研究。外生制度的静态比较是指在可控制条件下检验不同制度的有效性，着眼于比较不同制度下的贡献度以及社会福利等问题；而内生制度则扩展了有效性检验，人们可以通过选择不同的制度或治理结构来约束其行为，进而检验制度的稳定性。实验方法弥补了主流经验研究中不能对制度进行有效性检验这一不足，为研究制度经济学提供了一条新的思路。     

维生素A对肉牛脂肪沉积及其调控的研究进展

维生素A是肉牛维持正常生理功能、生化代谢及生长发育所必需的一类脂溶性维生素，机体自身不能合成，必须由饲粮供给。饲粮中维生素A不仅影响肉牛视觉和骨骼发育，也对肉牛脂肪沉积和肌肉大理石花纹形成等发挥着重要调控作用。在生产中，肉牛处在不同生理阶段对维生素A的需要量也不同，胎牛和犊牛阶段补充维生素A可增强肌内脂肪细胞发育和脂肪细胞增生，促进肌内脂肪沉积；育肥期限饲维生素A可提高肉牛的肌内脂肪沉积和大理石花纹等级。大理石花纹与牛肉的嫩度和风味密切相关，是衡量牛肉品质的重要指标。维生素A在肉牛体内通过其活性代谢产物视黄醇、视黄醛和视黄酸促进脂肪的形成，并在成脂定型、成脂分化和脂质蓄积的每个阶段都发挥重要作用。脂肪沉积过程受转录因子过氧化物酶体增殖物激活受体（peroxisome proliferator-activated receptors，PPARs）、CCAAT增强子结合蛋白（CCAAT-enhancer binding proteins，C/EBPs）和Janus激酶-信号转导及转录激活因子（JAK-STAT）信号转导通路等调控。表观遗传修饰的DNA甲基化和去甲基化也可通过调控脂肪形成过程中相关基因的表达参与脂肪细胞的分化和脂肪组织的生长发育，从而影响肉牛的脂肪沉积。作者主要介绍了脂肪组织不同阶段的形成过程和维生素A的生物学功能；重点阐述了肉牛在不同生理阶段补充和限饲维生素A，通过转录因子的表达、表观遗传修饰等途径来影响成脂相关信号通路调控脂肪沉积的机理，以期为促进维生素A改善肉牛品质和高档牛肉生产提供参考。     

凤庆茶叶种植与混林茶园生态系统研究

中国云南是世界茶树的原产地,而云南省凤庆县又是滇红的诞生地,具有悠久的茶树栽培种植历史,其混林茶园生态系统也具有较高的研究价值。本文通过对其茶叶种植史和混林茶园生态系统进行梳理和研究,厘清凤庆县茶叶种植的历史发展脉络,挖掘凤庆混林茶园生态系统的优势及其应用价值。     

雪山草鸡感染传染性法氏囊病病毒新型变异株的鉴定

传染性法氏囊病病毒(infectious bursal disease virus,IBDV)新型变异株正在我国广泛蔓延,给商品肉鸡群和蛋鸡群带来了新的威胁。本研究对一个疑似发生非典型传染性法氏囊病的地方品种雪山草鸡群进行了RT-PCR检测,并对分离的3株毒株进行了基因测序及序列分析。结果显示,引起该鸡群发病的病原是IBDV新型变异株,属于A2dB1基因型;这3个毒株的VP2高变区编码蛋白上含有IBDV变异株的特征性氨基酸,也具有IBDV新型变异株的独特氨基酸。结果提示,我国地方品种鸡群中也有IBDV新型变异株的流行,现有的部分商品化IBDV疫苗已不能有效预防IBDV新型变异株的流行。     

Prevention and Controlling Effect of Intercropping on Pests and Diseases and Its Risk Control in Cotton Fields

Cotton is one of the major field crops which are seriously threatened by pests and diseases. In recent years, the ecological management of cotton pests and diseases with intercropping has become to be an interesting approach. Intercropping possibly increases the population of natural enemies and finally reduces the population density of pests as a result of changes in ecological structure and environmental conditions of farmland. Intercropping thus has been considered an important alternative in controlling pests and diseases. However, cotton field intercropping also has some limitations in controlling pests and diseases. Unreasonable intercropping system has many risks such as increasing labor input, increasing the difficulty of pests’ control, and aggravating pests and diseases. In this paper, the effects and the underlying mechanisms of cotton intercropping on cotton pests and diseases were reviewed. The possible risks and countermeasures used for ecological control of intercropping were also put forward, and the future and application of ecological management of cotton pests and diseases with intercropping were prospected.