Physiological but not morphological adjustments along latitudinal gradients in a human commensal species,the Eurasian tree sparrow

Human commensal species take advantage of anthropogenic conditions that are less likely to be challenged by the selective pressures of natural environments. Their morphological and physiological phenotypes can therefore dissociate from habitat characteristics. Understanding how these species adjust their morphological and physiological traits across latitudinal gradients is fundamental to uncovering the eco-physiological strategies underlying coping mechanisms. Here, we studied morphological traits in breeding Eurasian tree sparrows (ETSs; Passer montanus) among low-latitude (Yunnan and Hunan) and middle-latitude (Hebei) localities in China. We then compared body mass; lengths of bill, tarsometatarsus, wing, total body, and tail feather; and baseline and capture stress-induced levels of plasma corticosterone (CORT) and the metabolites including glucose (Glu), total triglyceride (TG), free fatty acid (FFA), total protein, and uric acid (UA). None of the measured morphological parameters varied with latitude except in the Hunan population, which demonstrated longer bills than those in other populations. Stress-induced CORT levels significantly exceeded baseline levels and decreased with increasing latitude, but total integrated CORT levels did not vary with latitude. Capture stress-induced significantly increased Glu levels and decreased TG levels, independent of site. However, the Hunan population had significantly higher baseline CORT, baseline and stress-induced FFA levels, but lower UA levels, which differed from other populations. Our results suggest that rather than morphological adjustments, physiological adjustments are mainly involved in coping mechanisms for middle-latitude adaptation in ETSs. It is worth investigating whether other avian species also exhibit such dissociation from external morphological designs while depending on physiological adjustments.     

凝结芽孢杆菌对热应激肉鸡生长性能及肠道消化与吸收功能的影响

本试验旨在研究凝结芽孢杆菌对热应激肉鸡生长性能及肠道消化与吸收功能的影响。选择320只28日龄健康爱拔益加（AA）肉公鸡,随机分为5个组,每组8个重复,每个重复8只。常温对照组（TC组）肉鸡饲养于（22±1）℃的常温环境,饲喂基础饲粮;热应激组（HS组）肉鸡饲养于（34±1）℃的高温环境,饲喂基础饲粮;热应激试验组肉鸡饲养于（34±1）℃的高温环境,分别饲喂在基础饲粮中添加0.2×107(HS-BC0.2组)、1.0×107(HS-BC1.0组)、5.0×107CFU/g(HS-BC5.0组)凝结芽孢杆菌的试验饲粮。试验期14 d。结果表明：与TC组相比,HS组的末重、平均日增重（ADG）、平均日采食量（ADFI）,干物质和粗蛋白质表观代谢率,空肠食糜总淀粉酶和总蛋白酶酶活,空肠绒毛高度、绒毛高度/隐窝深度以及空肠钠/葡萄糖协同转运蛋白1(SGLT1)、基础氨基酸转运载体（r-BAT）、y+L氨基酸转运载体-1(y+LAT1) mRNA表达量均显著降低（P<0.05）,料重比（F/G）显著增加（P<0.05）。与HS组相比,HS-BC1.0和HS-BC5.0组的ADG、粗蛋...     

胺鲜酯(DA-6)浸种对盐胁迫下白三叶种子萌发及抗盐性的影响

以白三叶(Trifolium repens L.‘Haifa’)为研究对象,研究了0.8 mmol·L^-1胺鲜酯(DA-6)浸种处理对白三叶种子在盐胁迫条件下萌发的影响,并对DA-6诱导的耐盐机理进行初步研究,为白三叶的栽培管理提供参考。结果表明,DA-6浸种显著提高了盐胁迫下种子的发芽势、发芽率、活力指数、发芽指数、茎长和鲜干重(P<0.05)。盐胁迫显著诱导了游离脯氨酸和可溶性糖的积累,降低了细胞渗透势(P<0.05)。此外,盐胁迫导致了萌发种子中活性氧(超氧阴离子和过氧化氢)和膜脂过氧化产物丙二醛含量显著增加,电导率显著升高(P<0.05)。DA-6浸种前处理显著提高了胁迫下抗氧化酶(SOD、POD和APX)的活性,增幅分别为33.0%、31.9%和49.1%,这有效地缓解了由盐胁迫引起的氧化损伤,有利于幼苗稳定细胞膜(P<0.05)。本研究表明DA-6浸种处理通过增强抗氧化防御并降低细胞氧化伤害,从而提高盐胁迫下白三叶种子的萌发特性和胁迫耐受性。     

低磷胁迫对红豆草光合、叶绿素荧光及内源激素的影响

为探究低磷胁迫对红豆草(Onobrychis viciaefolia)光合作用、叶绿素荧光以及内源激素的影响,本试验采用营养液沙培法,以耐低磷5号和磷敏感1号红豆草为试验材料,设置常磷(1.00 mmol·L^-1 KH₂PO₄)和低磷(0.01 mmol·L^-1 KH₂PO₄)胁迫处理,于不同胁迫天数后测定形态、光合以及内源激素含量变化。结果表明：低磷胁迫抑制红豆草生长和光合作用,在低磷胁迫下,除非光化学淬灭系数外,供试红豆草叶绿素荧光参数均下降。随着胁迫时间的延长,2份红豆草材料地上和地下部玉米素(ZT)、脱落酸(ABA)、生长素(IAA)和赤霉素(GA₃)及其之间的比值变化趋势不一致,耐低磷红豆草地上和地下部ZT,GA₃,IAA,ABA耐低磷系数大于磷敏感材料。相关性分析表明,IAA与光合作用和叶绿素荧光显著相关,ABA与IAA,ZT,GA₃呈负相关。研究结果可为红豆草耐低磷特性研究提供...     

Fertility of Holstein cows and heifers submitted to timed artificial insemination and receiving one or two doses (12 h apart) of semen

The objective of this retrospective study was to assess the effect of receiving a single (n = 50,285) or double (n = 4392) artificial insemination (AI), 12 h apart, within a timed artificial insemination protocol on pregnancy per AI (P/AI) in nulliparous heifers (inseminated with either sex-sorted or conventional semen) and pluriparous Holstein cows in a commercial dairy herd. Also, this study aimed to investigate the relationship between temperature-humidity index (THI) and time of the first AI and fertility. Fertility of cows receiving two AI with normothermia (THI <68) was higher (p < .05) than cows receiving a single AI (42.9% vs. 36.4%). P/AI of cows receiving two AI with severe heat stress (THI >85) was higher (p < .05) than cows receiving a single AI (21.0% vs. 12.6%). Regardless of heat stress conditions, applying the first AI in the morning increased (p < .05) P/AI in cows with double AI than in cows whose first AI occurred in the afternoon (38.4 vs. 33.3%). With moderate heat stress, and sexed-sorted semen, P/AI to timed AI was higher (65.0 vs. 51.9%; p < .05) in heifers receiving double AI than those serviced once. It was concluded that double AI, 12 h apart, enhanced fertility at timed AI than herd mates with a single AI, particularly with heat stress at breeding.     

丛枝菌根真菌接种对白车轴草耐盐性的影响

丛枝菌根真菌(AMF)可与植物共生形成复杂的菌丝网络,影响植物生长及抗逆能力。目前关于AMF对白车轴草耐盐性的影响尚存争议,本研究采用盆栽试验,研究在盐胁迫条件下(NaCl浓度为150 mmol·L^-1),接种AMF对拉丁诺白车轴草耐盐性的影响。结果表明,在盐胁迫条件下,与对照相比,白车轴草的生长与生理指标均受到抑制。盐胁迫下接种AMF后,白车轴草株高、干重、PSⅡ最大光能转换效率和相对含水量均有增加,丙二醛(MDA)含量以及相对电导率有所降低,渗透调节物质均有提高,其中可溶性糖(SS)和游离脯氨酸(Pro)含量分别提高了32.03%和9.42%。说明盐胁迫抑制白车轴草的生长,接种AMF增强了白车轴草抗逆适应能力,促进白车轴草的生长,增加渗透调节物质含量,提高白车轴草耐盐胁迫的能力。     

盐胁迫对5份无芒雀麦苗期生长和生理生化的影响及综合性评价

为了明确不同无芒雀麦苗期耐盐能力的强弱,本研究选择5份不同株型的无芒雀麦作为供试材料。根据新疆土壤盐碱成分设置中性盐(M盐)：NaCl∶Na₂SO₄∶Na₂CO₃=1∶4∶0和碱性盐(A盐)：NaCl∶Na₂SO₄∶Na₂CO₃=1∶1∶8两种处理,于三叶期每盆一次性浇灌2 L电导率(EC)为20 ms·cm^-1的盐处理液,CK浇灌等量自来水。处理30 d后测定生长指标、叶绿素荧光特性参数、丙二醛(MDA)和渗透调节物质含量,并通过相关性分析、主成分分析、隶属函数分析对13个指标进行分析评价。结果表明：除F_v/F_m和F_v/F_o外,盐胁迫显著影响其余11个指标,且5份材料间差异显著(P<0.05);5份无芒雀麦的株高、茎粗、分蘖数、地上生物量、根冠比、MDA和脯氨酸含量在不同盐胁迫下表现出不同的适应变...     

紫花苜蓿种子吸胀期胚根线粒体AsA-GSH循环对低温胁迫的响应

为探究胚根线粒体抗坏血酸-谷胱甘肽(AsA-GSH)循环响应低温胁迫的抗氧化作用机制,以紫花苜蓿种子为材料,研究了不同温度(10和20℃)处理下发芽特性、不同吸胀时间(6、12和24 h)胚根线粒体AsA-GSH循环酶活性、抗氧化物以及过氧化氢(H₂O₂)含量的变化规律。结果表明,吸胀12和24 h后,10℃处理的胚根线粒体H₂O₂含量高于20℃。吸胀24 h期间,10℃处理的胚根线粒体谷胱甘肽还原酶(GR)活性均低于20℃。吸胀12和24 h后,10℃处理的胚根线粒体抗坏血酸(AsA)含量均低于20℃。10℃条件下吸胀24 h后,与20℃处理相比,胚根线粒体谷胱甘肽(GSH)含量显著降低(P<0.05)。苜蓿种子在10℃条件下吸胀萌发时,主要通过降低AsA-GSH循环中GR、单脱氢抗坏血酸还原酶(MDHAR)、过氧化物酶(POD)活性和AsA、GSH含量,使胚根线粒体内的H₂O₂积累,产生氧化损伤,继而影响种子萌发的正常进程。     

右美托咪定抑制NOX4缓解急性应激致大鼠肾损伤

本研究拟探索右美托咪定（dexmedetomidine,DEX）对大鼠急性应激致肾损伤的保护作用,并从氧化应激的角度探索DEX对大鼠肾的保护通路。本研究使用了急性束缚应激模型,其中,大鼠被迫游泳15 min,并束缚3 h。本试验采用生化检测、组织病理学切片观察以评估肾功能,然后测定了氧化应激以及氧化应激的相关通路蛋白。旷场试验证实成功建立了急性应激模型。急性应激引起的肾损伤增加了NOX4,降低了Nrf2/HO-1/NQO1表达水平。DEX可降低NOX4表达,同时升高Nrf2/HO-1/NQO1的表达水平。DEX治疗组与急性应激组相比的肾生化结果明显恢复正常,病理切片观察损伤显著降低。试验结果表明,DEX治疗急性应激可影响NOX4/Nrf2/HO-1/NQO1信号通路,并抑制氧化应激。因此,DEX对急性应激引起的肾损伤具有保护作用,并在应激综合征中具有潜在的临床应用。     

沙引发对紫花苜蓿种子盐逆境下发芽及幼苗生理生化变化的影响

试验以紫花苜蓿品种维多利亚和金皇后种子为材料，研究了沙引发处理对高盐(0．8％NaCl)逆境下种子发芽及幼苗生理生化变化的影响。结果表明，沙引发处理能显著提高紫花苜蓿两个品种种子的发芽率、发芽势、发芽指数和活力指数，缩短平均发芽时间，显著增加幼苗干重，同时提高了过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性，减少丙二醛(MDA)的积累。说明沙引发提高了紫花苜蓿种子的活力和抗盐胁迫能力，促进了盐逆境下种子的萌发和幼苗生长。