鸡Hsc70基因5′侧翼区SNP与耐热性状的相关分析

为研究Hsc70基因作为鸡抗病育种中一种分子标记的可能性,本试验利用克隆测序技术对清远麻鸡、广东温氏矮脚黄鸡、灵山鸡和隐性白羽洛克鸡4个品种共20个个体Hsc70基因的5′侧翼区进行多态性筛查,发现10处变异,包括8个SNPs和2个插入/缺失突变。通过分析,选取C.-521A〉C位点,利用PCR-RFLP方法分析了此位点在灵山鸡和隐性白羽洛克鸡群体中的基因型分布,所得分型结果与测定的耐热性状（T3、皮质酮、CD3＋、CD4＋和CD8＋）进行关联分析,结果表明：常温状态下（15℃）,在隐性白羽洛克鸡群体中,位点C.-521A〉C与CD3＋、CD4＋和CD8＋显著相关（P〈0.05）,其中AA基因型个体CD3＋值显著低于AC基因型个体,而CD4＋与CD8＋值显著高于AC基因型个体;热应激状态下（35℃）,在灵山鸡群体中,位点C.-521A〉C与CD8＋极显著相关（P〈0.01）,CC基因型个体CD8＋值极显著高于AA和AC基因型。     

The Alleviating Effect of Elevated CO2 on Heat Stress Susceptibility of Two Wheat (Triticum aestivum L.) Cultivars

This study analysed the alleviating effect of elevated CO₂ on stress‐induced decreases in photosynthesis and changes in carbohydrate metabolism in two wheat cultivars (Triticum aestivum L.) of different origin. The plants were grown in ambient (400 μl l^?1) and elevated (800 μl l^?1) CO₂ with a day/night temperature of 15/10 °C. At the growth stages of tillering, booting and anthesis, the plants were subjected to heat stress of 40 °C for three continuous days. Photosynthetic parameters, maximum quantum efficiency of photosystem II (PSII) photochemistry (F_v/F_m) and contents of pigments and carbohydrates in leaves were analysed before and during the stress treatments as well as after 1 day of recovery. Heat stress reduced P_N and F_v/F_m in both wheat cultivars, but plants grown in elevated CO₂ maintained higher P_N and F_v/F_m in comparison with plants grown in ambient CO₂. Heat stress reduced leaf chlorophyll contents and increased leaf sucrose contents in both cultivars grown at ambient and elevated CO₂. The content of hexoses in the leaves increased mainly in the tolerant cultivar in response to the combination of elevated CO₂ and heat stress. The results show that heat stress tolerance in wheat is related to cultivar origin, the phenological stage of the plants and can be alleviated by elevated CO₂. This confirms the complex interrelation between environmental factors and genotypic traits that influence crop performance under various climatic stresses.     

氧化应激状态下仔猪海马差异表达miRNAs与转录组的关联分析

旨在解析仔猪脑海马背、腹侧区域参与氧化应激反应的小RNA（miRNA）靶基因及可能的调节机制。本研究基于前期投放到基因表达数据库（GEO）中的miRNAs和转录组数据包,采用生物信息学分析方法,对氧化应激荣昌仔猪脑海马背、腹侧区域差异表达的miRNA进行靶基因预测,并将预测的结果和转录组数据进行重叠筛选,将筛选得到的miRNA-mRNA构建互作网络图,并对靶基因进行GO分类和KEGG分析,以期探索仔猪脑海马背、腹侧区域中参与氧化应激调控的分子机制。结果表明,氧化应激分别引起了仔猪脑海马背侧309对和腹侧247对负向调控的miRNA-mRNA差异表达,其中,已知的差异表达miRNAs（DE miRNAs）负向调控差异表达mRNA（DE mRNAs）的互作网络背侧有67对（2对上调miRNA-下调mRNA,65对下调miRNA-上调mRNA）,腹侧有41对（3对上调miRNA-下调mRNA,38对下调miRNA-上调mRNA）。GO分类和KEGG分析结果显示,miRNA靶向上调的基因主要调节氧化应激损伤和维持机体稳态;而靶向下调的基因,背侧主要调节细胞凋亡,腹侧主要调节细胞增殖、迁移等。并且部分DE miRNAs能够通过对基因的靶向调节协同或发散地参与对氧化应激相关神经系统疾病的调控。本研究首次描述了仔猪脑海马中与氧化应激相关的miRNA-mRNA的相互作用网络和信号通路,剖析了仔猪海马背、腹侧对氧化应激调节的差异性和一致性,为氧化应激介导的神经性疾病病理机制的研究奠定了基础。     

骆驼乳清蛋白对热应激所致大鼠肝氧化损伤的保护作用

本试验旨在研究骆驼乳清蛋白（CWP）对热应激（HS）大鼠肝损伤、氧化应激及肝功能的保护作用。选取6周龄SD大鼠36只,适应性饲养2周后随机分为6组：正常对照组饲喂基础日粮;CWP对照组添加400 mg·kg^-1的CWP;HS组除饲喂基础日粮外,每天进行2 h HS处理,连续8 d;3个CWP干预组分别于每次HS前灌服100、200和400 mg·kg^-1的CWP。试验结束后,取大鼠肝组织,HE染色观察肝组织病理学变化,同时检测肝功能生物标志物、氧化应激标志物水平及抗氧化酶活性。结果表明：CWP降低了HS大鼠血清谷草转氨酶（AST）和谷丙转氨酶（ALT）活性,400 mg·kg^-1的CWP干预效果最好（P<0.01）;400 mg·kg^-1CWP干预组有效降低了HS诱导的大鼠肝组织病理学改变; CWP降低了大鼠肝活性氧（ROS）及丙二醛（MDA）水平,增加了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH-Px）活性及谷胱甘肽（GSH）水平,400 mg·kg^-1的CWP干预效果最好（P<0.01）。结果提示,CWP干预能够以剂量依赖性方式降低大鼠肝氧化应激,增加抗氧化系统防御能力,从而缓解HS所致大鼠肝损伤。     

Developmental competence of heat stressed oocytes from Holstein and Limousine cows matured in vitro

The negative effects of heat stress on dairy cattle's fertility have been extensively studied, but the relevant knowledge for beef cattle is rather limited. The aims of this study were to investigate the effects of HS during in vitro maturation on the developmental potential of oocytes derived from Limousine and Holstein cows and to estimate the effect of the differential gene expression of important genes in oocytes, cumulus cells and blastocysts in the growth competence between the breeds. In seven replicates, cumulus oocyte complexes from Holstein and Limousine cows were matured for 24 hr at 39°C (controls C; Hol_39, Lim_39) or at 41°C from hour 2 to hour 8 of IVM (treated T; Hol_41, Lim_41), fertilized, and presumptive zygotes were cultured for 9 days at 39°C. Cleavage and embryo formation rates were evaluated 48 hr post-insemination and on days 7, 8 and 9, respectively. From all groups, subsets of cumulus cells, oocytes and blastocysts were analysed for the relative expression of genes related to metabolism, stress, apoptosis and placentation. No difference was detected in cleavage rate or in blastocyst formation rate among the control groups. In both breeds, heat stress reduced blastocyst yield, but at all days the suppression was higher in Limousines. In Holsteins, altered gene expression was detected in cumulus cells (G6PD, GLUT1) and blastocysts (PLAC8), while in Limousines, differences were found in oocytes (G6PD, HSP90AA1), in cumulus cells (CPT1B, HSP90AA1, SOD2) and blastocysts (DNMT, HSP90AA1, SOD2). It appears that Holstein COCs are more tolerant than Limousine COCs, possibly due to compulsory, production driven selection.     

Ultrasonographic findings of the corpus luteum and the gravid uterus during heat stress in dairy cattle

The objectives of this study were to assess alterations in, echogenic appearance, size and blood flow in the corpus luteum, the placentomes and the blood flow in umbilical and uterine arteries that heat stress can cause in cooled pregnant dairy cows. Pregnant cows were allocated in two groups and the gravid uteri, along with the ipsilateral corpora lutea were examined during the winter (group W, n = 9) or the summer (group S, n = 10). The grey-scale ultrasound and colour flow imaging of the corpus luteum and placentome were performed. In addition, the umbilical and uterine artery diameters and haemodynamic parameters in the vessels were calculated. At the time of ultrasonographic examination, cortisol concentrations were higher, and progesterone levels tended to be lower in group S compared to group W. The grey-scale ultrasound evaluation of corpora lutea and placentomes was lower in group S compared to group W. The diameter of umbilical artery and the blood volume in the vessel were less in group S than in group W. We infer that heat stress affects foetal blood supply and possibly the structure of placentomes and corpora lutea, but it differently affects the blood flow characteristics in the umbilical and uterine arteries.     

山奈酚对三硝基丙酸诱导氧化应激胎鼠的影响

试验旨在研究山奈酚对三硝基丙酸诱导亲代小鼠氧化应激从而对子代胎鼠氧化应激和抗氧化能力的作用。42只亲代小鼠分为3组:对照组、氧化应激模型组、抗氧化剂组,试验重复3次。测定妊娠20 d后的子代胎鼠肝脏、肺脏和心脏3个器官中的总超氧化物歧化酶(T-SOD)活力、谷胱甘肽过氧化物酶(GSH-Px)活力、总抗氧化能力(T-AOC)、丙二醛(MDA)含量和过氧化氢酶(CAT)活力。结果显示,山奈酚显著代偿降低子代胎鼠心、肝、肺相关抗氧化酶的活力(P<0.05),显著降低氧化应激产物的含量(P<0.05)。研究表明,山奈酚对于由三硝基丙酸诱导的亲代小鼠氧化应激模型的子代胎鼠氧化应激情况具有一定的抗氧化作用。     

紫花苜蓿形态和生理指标响应干旱胁迫的品种特异性

为研究紫花苜蓿在叶片和根系水平上响应干旱胁迫的形态和生理的品种特异性规律,在温室内分析了干旱胁迫下WL363HQ和巨能7紫花苜蓿株高、分枝数、生物量及叶片和根系中丙二醛（MDA）、脯氨酸、抗氧化酶类物质、C、N含量、C/N、稳定性C同位素（δ¹³C）和稳定性N同位素（δ¹⁵N）。结果表明：干旱胁迫显著降低了供试品种地上部分和根系的干重及分枝数（P<0.05）。干旱胁迫显著降低了巨能7的株高（P<0.05）,但增加了巨能7的根冠比,而WL363HQ的结果与之相反,这说明干旱胁迫下供试品种的株高和根冠比具有品种特异性的规律。干旱胁迫增加了WL363HQ和巨能7叶片和根系中MDA和脯氨酸的含量及抗氧化酶物质的活性,且在器官水平也具有品种特异性规律。干旱胁迫下巨能7叶片的MDA含量显著增加（P<0.05）,而在WL363HQ根系中的MDA含量也显著增加（P<0.05）。干旱胁迫下WL363HQ叶片脯氨酸含量、POD和SOD活性,及根系SOD的活性均显著增加（P<0.05）,而巨能7仅叶片SOD活性,根系脯氨酸含量、POD活性显著升高（P<0.05）。尽管干旱胁迫对供试品种叶片和根系C、N含量无显著影响（P>0.05）,但干旱胁迫显著提高了WL363HQ和巨能7紫花苜蓿根系的δ¹³C（P<0.05）,且WL363HQ叶片的δ¹⁵N均显著高于巨能7（P<0.05）。此外,干旱胁迫均显著提高了巨能7叶片和根系的C/N（P<0.05）。干旱胁迫下供试品种C、N代谢参数并没有在叶片和根系中表现出较为明显的品种特异性规律,深层次的机制还有待进一步研究。本研究结果将为进一步掌握紫花苜蓿叶片和根系协同抗旱机制及抗旱丰产紫花苜蓿新品种的选育提供理论依据。     

三种荒漠植物叶绿素荧光参数日变化特征

利用Photosynq MultiseQ多功能植物测量仪测定塔克拉玛干沙漠腹地3种主要防护林植物头状沙拐枣、多枝柽柳和梭梭的叶绿素荧光参数日变化,探讨其与环境因子的关系,以揭示3种植物对极端环境的适应策略,为沙漠公路防护林的管护提供理论依据。结果表明：1）3种土壤都呈碱性;0~30 cm土层中的电导率（EC）远高于30 cm以下的土层。1 m内梭梭土层中的含水量高于多枝柽柳高于头状沙拐枣。2）3种植物的光合有效辐射（PAR）、叶片温度和线性电子传递（LEF）及植物周围的大气温度日变化均先升后降,且都在14：00达到最高;而大气湿度、实际光化学效率Y_（II）日变化均呈‘V’型。3）PAR基本上与3种植物的LEF、非光化学淬灭系数（NPQ）、调节性能量耗散量子产量Y_（NPQ）、非调节性能量耗散量子产量Y_（NO）呈显著正相关,与实际光化学效率Y_（II）呈显著负相关;3种植物的Y_（II）与Y_（NPQ）、Y_（NO） 均呈极显著负相关。3种植物的LEF、Y_（II）、Y_（NPQ）的日均值差异不显著,但梭梭与多枝柽柳的NPQ和Y_（NO）日均值差异显著。4）在3种植物的叶绿素荧光参数中,梭梭和头状沙拐枣的LEF、NPQ和Y_（II）要高于多枝柽柳;而多枝柽柳的Y_（NO）要显著高于头状沙拐枣和梭梭。因此,高温和高光均对3种植物造成了不同程度的影响,通过主成分分析表明,3种植物的抗逆性强弱顺序分别为梭梭>头状沙拐枣>多枝柽柳。     

锰胁迫下鸡眼草的富集特征及生理响应

为探明植物对锰胁迫的耐受性机制,以采自重金属污染区与非污染区的鸡眼草为试验材料,在不同锰浓度胁迫下［0 （对照）、1000、5000、10000、15000、20000 μmol·L^-1］ 开展盆栽试验,比较研究锰胁迫对两种来源鸡眼草表型、生理生化特性及锰积累特征的影响。结果表明：随着锰浓度的升高,1） 两种来源鸡眼草的根干重、芽干重、根冠比均呈降低的趋势;当锰浓度达5000~20000 μmol·L^-1时,与对照相比,污染区、非污染区鸡眼草的芽干重分别下降4.34%~27.71%与16.33%~49.77%,根干重分别下降19.00%~66.06%与27.90%~77.54%,污染区下降幅度均较非污染区的小;2） 两种来源鸡眼草的叶绿素、可溶性糖、脯氨酸含量及超氧化物歧化酶（SOD）、过氧化物酶（POD）活性均呈先升后降的趋势,可溶性蛋白含量逐渐下降,丙二醛（MDA）含量则逐渐升高;3） 两种来源鸡眼草根、茎、叶的锰含量均增加;锰浓度为20000 μmol·L^-1时,污染区和非污染区鸡眼草的叶锰含量分别为对照的16.53和13.41倍。因此,污染区鸡眼草锰耐受能力及富集能力均较非污染区鸡眼草高,较高的抗氧化酶活性是其耐受高锰胁迫的重要生理机制。