低氧应激下甘肃鼢鼠与SD 大鼠心脏抗氧化酶和ATP 酶活性的比较

为探讨低氧应激下甘肃鼢鼠心脏对抗氧化损伤和电生理紊乱的可能机制,对甘肃鼢鼠和SD 大鼠在4. 5%氧浓度下分别进行2 h、4 h、6 h、8 h、10 h、16 h 低氧应激,比较常氧和各时程低氧下二者心脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)和Ca^{2 +} - ATP 酶、Ca^{2 +} - Mg^{2 +} - ATP 酶、Na ⁺ - K ⁺ - ATP酶活性,以丙二醛(MDA)含量作为机体氧化损伤指标。结果显示,常氧组甘肃鼢鼠GR 活性比SD 大鼠高,SOD、CAT、Ca^{2 +}-ATP 酶、Ca^{2 +} - Mg^{2 +} - ATP 酶和Na ⁺ - K ⁺ - ATP 酶活性及MDA 含量与SD 大鼠相比均无显著性差
异;低氧组甘肃鼢鼠SOD、CAT、GR、Ca^{2 +} - ATP 酶、Ca^{2 +} - Mg^{2 +} - ATP 酶和Na ⁺ - K ⁺ - ATP 酶活性迅速升高,显著高于SD 大鼠,MDA 含量则显著低于SD 大鼠。说明甘肃鼢鼠心脏通过提高抗氧化酶活性清除低氧诱导产生的多余自由基,并通过提高ATP 酶活性保证心电活动正常、心率稳定,应对低氧应激。     

常氧条件下高原鼢鼠、甘肃鼢鼠及SD大鼠血液理化特征比较

为探讨不同低氧环境适应动物的血液理化特征,用美国雅培手掌血气分析仪分别测定常氧适应4周的高原鼢鼠(Myospalax baileyi)及甘肃鼢鼠(M.cansus)血液的血气、酸碱及电解质指标,并与SD大鼠(Rattus norvegicus)进行比较。结果显示,常氧适应后,甘肃鼢鼠与高原鼢鼠动脉氧分压(PaO2)、静脉氧分压(PvO2)、动静脉氧分压差(PaO2﹣PvO2)、动脉氧饱和度(SaO2)、静脉氧饱和度(SvO2)及氧利用率均无显著性差异,两种动物静脉血的氧分压和氧饱和度均极显著低于SD大鼠,氧利用率极显著高于SD大鼠;高原鼢鼠与甘肃鼢鼠动、静脉血红蛋白(Hb)及动、静脉红细胞压积(HCT)无显著性差异,血红蛋白含量与SD大鼠无显著性差异,但红细胞压积(HCT)极显著低于SD大鼠;高原鼢鼠和甘肃鼢鼠血液酸碱特征趋于一致,不同于SD大鼠,动静脉pH差(pHa﹣pHv)及动静脉CO2总含量差(TvCO2﹣TaCO2)显著高于SD大鼠,动脉二氧化碳分压(PaCO2)极显著低于SD大鼠,动静脉二氧化碳分压差(PvCO2﹣PaCO2)极显著高于SD大鼠;高原鼢鼠和甘肃鼢鼠血浆中钠离子(Na+)浓度、钾离子(K+)浓度、游离钙离子(iCa2+)浓度及动静脉钠离子浓度差(Na+v﹣Na+a)、钾离子浓度差(K+v﹣K+a)和游离钙离子浓度差(iCa2+v﹣iCa2+a)无显著性差异;高原鼢鼠动脉血钾离子浓度显著低于SD大鼠,钾离子浓度差显著高于SD大鼠;甘肃鼢鼠钾离子浓度差及动、静脉血钙离子浓度显著高于SD大鼠。这些结果说明,低氧适应动物血气、酸碱及电解质特征一致,与地面生活的SD大鼠差异很大,表现出较低的红细胞压积和较高的氧利用率,血液能耐受较宽范围的酸碱变化,维持电解质稳定,保证内环境稳态。     

甘肃鼢鼠与SD大鼠骨骼肌低氧适应的比较

运用组织学和紫外分光光度法,对常氧、低氧2周和4周的甘肃鼢鼠(Myospalax cansus)及SD大鼠(Rattus norvegicus)骨骼肌形态结构、乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)活力及肌红蛋白(Mb)浓度进行测定。结果显示,甘肃鼢鼠骨骼肌形态结构在常氧、低氧2周及4周后变化不明显;SD大鼠随低氧时间延长发生显著变化,低氧2周后,肌纤维明显萎缩,间隙增大,结构较紊乱;低氧4周后,肌纤维破裂,呈细丝状,不规则,大小不一致,肌节紊乱。甘肃鼢鼠LDH活性随低氧时间增长逐渐降低,但无显著性差异(P0.05);在不同时间低氧处理后,甘肃鼢鼠前后肢的LDH活性均极显著低于SD大鼠(P0.01);常氧条件下,甘肃鼢鼠前后肢SDH活性低于SD大鼠,但无显著差异(P0.05),低氧2周及4周后,与SD大鼠呈极显著差异(P0.01);常氧条件下,甘肃鼢鼠前后肢Mb浓度均显著高于SD大鼠(P0.05),低氧2周及4周后,极显著高于SD大鼠(P0.01)。结果表明,甘肃鼢鼠骨骼肌较SD大鼠有着更强的低氧耐受力。     

甘肃鼢鼠血象及其与低氧适应的关系

甘肃鼢鼠(Myospalax cansus)是一种严格营地下生活的鼠类,其形态、行为及生理特征均与地面鼠不同。为探讨甘肃鼢鼠适应低氧环境的机理,本研究采用血象指标测定方法,对甘肃鼢鼠低氧适应前后的红细胞数、血红蛋白浓度、红细胞压积等各血象指标进行测定。结果显示,甘肃鼢鼠低氧适应后红细胞数、血红蛋白浓度和红细胞压积均显著升高,而平均红细胞体积、平均红细胞血红蛋白及平均红细胞血红蛋白浓度明显下降。与地面生活的啮齿动物低氧适应后血象相比,甘肃鼢鼠红细胞数量多,红细胞压积大,血红蛋白浓度高,红细胞膜表面积大,血红蛋白的利用率较高,可能是对低氧环境适应的一种途径。     

甘肃鼢鼠低氧适应后心功能的变化

甘肃鼢鼠Eospalax cansus是生活在我国黄土高原地区的地下鼠,是一种缺氧耐受的模型鼠,具有多种机制来适应其特殊的生活环境。为了比较慢性间歇性低氧后与地面常氧状态下甘肃鼢鼠的心脏功能,将18只甘肃鼢鼠随机分为对照组(常氧)和实验组(慢性间歇性低氧)检测其心脏功能。结果表明,低氧适应后实验组的心率较对照组显著提高(P0.05);平均颈动脉压力、左心室收缩压较对照组极显著升高(P0.01);左心室内压最大上升速率和左心室内压最大下降速率与对照组差异无统计学意义。表明甘肃鼢鼠存在一定低氧适应机制,在低氧刺激下其心脏代偿功能得到发挥,从而减轻缺氧对其心脏的损伤。     

急性低氧下去甲肾上腺素对大鼠淋巴细胞转化的调节作用

本研究以模拟高原低氧方法,观察低氧作用于大鼠细胞免疫功能以及去甲肾上腺素对免疫作用的调节机制。实验结果：与对照相比,７ｋｍ急性低氧２４ｈ淋巴细胞转化下降４１％（Ｐ〈０．０１）;５ｋｍ低氧暴露时间为７ｄ,２０ｄ时,低氧抑制淋巴细胞转化,分别下降３４％和６０％（Ｐ〈０．０１）,侧脑室注入５ｎｍｏｌ／Ｌ ＮＥ,淋巴细胞转化比对照下降２９％（Ｐ〈０．０１）,７ｋｍ１０ｈ低氧暴露时,侧脑室注入酚妥拉明２５μ     

低氧对甘肃鼢鼠体内ACTH及血液生理指标的影响

为研究低氧对甘肃鼢鼠(Myospalax cansus)血清促肾上腺皮质激素(ACTH)及血液生理指标的影响,采用KX-21N全自动血液分析仪对甘肃鼢鼠低氧处理前后血液中红细胞数(RBC)﹑血红蛋白浓度(HGB)﹑红细胞压积(HCT)、平均红细胞体积(MCV)、平均血红蛋白含量(MCH)及平均血红蛋白浓度(MCHC)进行测定,并采用SN-695A型智能放免r测量仪测定血清中ACTH浓度。结果表明,氧浓度分别为14.1%、10.5%和6.5%条件下,甘肃鼢鼠RBC、HGB和HCT均显著升高,MCV变化不明显,MCH和MCHC下降,血清ACTH含量显著升高;腹腔注射ACTH后甘肃鼢鼠RBC、HGB、HCT均显著升高。说明低氧激活了甘肃鼢鼠下丘脑-垂体-肾上腺皮质轴(HPA),导致ACTH分泌增加,刺激皮质酮分泌,致RBC、HGB、HCT含量增加,从而提高血液中红细胞的携氧能力以适应低氧生活环境。     

急性低氧对大鼠血液中儿茶酚胺及血小板聚集性的影响

健康ＳＤ雄性大鼠,体重２５０－３００ｇ,麻醉、气管插管,用人工呼吸机经气袋供气,自发吸入氧浓度为９％的氧氮混合气,用高效液相色谱－电化学联合检测法及电阻法检测循环血液中儿茶酚胺及全血血小权聚集性的动态变化。结果：急性低氧１５ｍｉｎ时血液中肾肾上腺素（Ａ）浓度及全血血小板聚集性显著增加（Ｐ〈０．０１）,而去甲肾上腺素（ＮＡ）浓度虽有所增加,但无统计学意义（Ｐ〉０．０５）;复氧１５ｍｉｎ时血液中儿茶酚     

高原鼢鼠和甘肃鼢鼠胆汁无机元素含量分析

<正>无机元素在动物发育、免疫调节、代谢和繁殖等方面发挥着重要作用(刘季科等,1991;蒲俊华等,2010;Talebnejadetal.,2021;Gashkinaet al., 2022)。现代医学已证明,无机元素的种类和含量影响药材的药性和药效(谭文敏,2015;陈虹等,2017),其已逐渐成为动物药鉴别、炮制加工、质量评价和寻找替代品的重要依据(罗兴洪等,2004)。熊胆属于传统珍稀濒危动物药,     

急性低氧对血浆皮质醇浓度及海马去甲肾上腺素含量的影响

本工作观察不同氧浓度,不同低氧时间猫血浆皮质醇浓度和海马内去甲肾上腺素含量的改变,以分析海马在低氧应激过程中的作用,结果显示,吸入１０．４％及７．９％Ｏ２后,猫血浆皮质醇浓度逐渐升高,分别于４５ｍｉｎ及３０ｍｉｎ达峰值;而低氧３０ｍｉｎ后,海马组织中的ＮＥ含量明显降低,两者与低氧程度无明显关系。     

青藏高原东缘高寒草原有毒植物分布与高原鼠兔、高原鼢鼠的相关性

青藏高原高寒草原生态系统是我国特有的生态系统类型,由于受到人为破坏的影响,目前该地区草原生态系统功能退化,优良牧草减少,有毒植物蔓延。高原鼠兔(Ochotona curzoniae)和高原鼢鼠(Myospalax baileyi)是青藏高原东缘高寒草原中最重要的两种小型哺乳动物,其采食行为和挖掘洞穴的生活特性必然对生态系统产生影响,但其与有毒植物之间的互作关系尚未揭示。基于此,在甘肃省玛曲县河曲马场自然生长的高寒草原生态系统中开展了有毒植物的分布与高原鼠兔、高原鼢鼠之间的相关性研究。结果表明,该高寒草原生态系统中分布有毒植物27种,分属于菊科、豆科、毛茛科等11科。在此基础上,测定了该地区有毒植物的生物多样性指数、均匀度指数和丰富度指数,并探究了单位面积条件下有毒植物的分布特征与高原鼠兔和高原鼢鼠种群密度之间的相关性,发现该地区高寒草原有毒植物的蔓延与高原鼠兔的密度之间存在密切的负相关关系(P0.05),而与高原鼢鼠的相关性不显著(P0.05)。     

Hypoxia and seasonal temperature: Short-term effects and long-term implications for Acartia tonsa dana

Far more attention has been given to the short-term lethal impacts of reduced dissolved oxygen on commercially important fish and crabs than to the long-term sublethal impacts on these same species, or on lower trophic levels. This study demonstrates that chronic, sublethal effects of hypoxia on the copepod Acartia tonsa, a critical component of many pelagic coastal food webs, can lead to significant decreases in population growth. The results of laboratory experiments conducted at 15 °C (winter) and 25 °C (summer), under conditions of normoxia (Controls), sublethal hypoxia (1.5 ml l^− 1) and lethal hypoxia (0.7 ml l^− 1) show that egg production female^− 1 day^− 1 was significantly lower at 0.7 ml l^− 1 compared to Controls at both temperatures, while egg production female^− 1 day^− 1 was significantly lower at 1.5 ml l^− 1 compared to controls in both summer experiments and in one of the two winter experiments. Survival was significantly decreased in the 0.7 ml l^− 1 treatment compared to Controls and the 1.5 ml l^− 1 treatment. Copepods developed more slowly and matured at smaller adult body sizes at both temperatures under both lethal and sublethal hypoxia compared to normoxia. Under summer temperatures, egg production was reduced by hypoxia exposure on two counts: (1) exposure to hypoxia during development resulted in smaller adults, which translated into lower egg production, and (2) egg production was still significantly lower in hypoxia treatments compared to Controls even when differences in body size were taken into account. While copepods collected in winter and exposed to winter temperatures and hypoxia also matured at smaller body sizes than copepods exposed to normoxia, egg production in winter was almost entirely attributable to this reduction in body size. These results suggest that coastal hypoxia may have a significantly greater impact in the summer months, when copepod populations are most abundant and growing at their most rapid rate of the year. With the anticipated increases in global temperatures, hypoxia may have even greater impacts on pelagic food webs.     

Hypoxia and sulphide influence gamete production in Ulva sp.

Gamete production after exposure to hypoxia or sulphide was studied in the marine macroalga Ulva sp. collected in the Sacca di Goro, Italy. Experiments were carried out on discs (12 mm diameter) of thalli cultured in artificial sea water in laboratory at 20 ± 1 °C, 152 μmol m⁻² s⁻¹, 16 h photoperiod and 30‰ salinity. Dehydration of thallus was used as inducer of gametogenesis and growth and gamete release during recovery after 10, 20, 30 or 40 min dehydration (20 ± 1 °C, 25% humidity) were analysed. Unlike non-dehydrated thalli the dehydrated ones produced gametes. Thallus discs, non-dehydrated or subjected to 30 min dehydration, were exposed to hypoxia (1.78–4.02 μmol O₂ L⁻¹) or sulphide (1 mM) for 3, 5, or 7 days at 20 °C in the dark. Non-dehydrated and dehydrated thalli maintained in normoxic conditions in the dark were the controls. Gamete density was checked by counting at the end of the incubation period and during the subsequent 7 days of recovery under 16 h photoperiod in normoxic conditions. Non-dehydrated thalli maintained in normoxic conditions in the dark released gametes when returned to light suggesting that dark constitutes a stimulus to gamete production. The presence of gametes at the end of 3 days incubation of dehydrated thalli in normoxia demonstrated that gametogenesis can occur even in the dark. However, gametes were not present at the end of incubation in hypoxic and sulphidic conditions. Actually, during hypoxic incubation oxygen consumption in D-thalli was very low, only 0.117 × 10⁻³ μmol O₂ mg⁻¹ h⁻¹ compared to 5.93 × 10⁻³ μmol O₂ mg⁻¹ h⁻¹ in normoxia, denoting a reduction of the metabolic rate that could not sustain gametogenesis. During recovery after incubation in normoxic, hypoxic or sulphidic conditions densities of gametes from dehydrated thalli showed significant differences and resulted after hypoxia > after normoxia > after sulphide. Differences in non-dehydrated thalli were not significant. Dehydrated thalli, still green at the end of the incubation period, underwent blanching in the course of recovery in parallel to gamete production, while non-dehydrated thalli maintained their green colour even after exposure to sulphide. Our findings suggest that macroalga Ulva sp. can survive exposure to darkness, severe hypoxia and high sulphide levels and can maintain gamete production even when the exposure to these stress conditions is joined to dehydration.     

RPB2 sequences reveal a close phylogenetic relationship between tetraploid Hordelymus and diploid Hordeum species in Triticeae (Poaceae)

The origin of Hordelymus genome has been debated for years, and no consensus conclusion was reached. In this study, we sequenced and analyzed the RPB2 (RNA polymerase subunit II) gene from Hordelymus europaeus (L.) Harz, and its potential diploid ancestor species those were suggested in previous studies. The focus of this study was to examine the phylogenetic relationship of Hordelymus genomes with its potential donor Hordeum, Psathyrostachys, and Taeniatherum species. Two distinguishable copies of sequences were obtained from H. europaeus. The obvious difference between the two copies of sequences is a 24 bp indel (insertion/deletion). Phylogenetic analysis showed a strong affinity between Hordeum genome and Hordelymus with 85% bootstrap support. These results suggested that one genome in tetraploid H. europaeus closely related to the genome in Hordeum species. Another genome in H. europaeus is sister to the genomes in Triticeae species examined here, which corresponds well with the recently published EF-G data. No obvious relationship was found between Hordelymus and either Ta genome donor, Taeniatherum caput-medusae or Ns genome donor, Psathyrostachys juncea. Our data does not support the presence of Ta and Ns genome in H. europaeus, and further confirms that H. europaeus is allopolyploid.     

投喂不同油脂饲料对中华绒螯蟹免疫、代谢及耐低氧性能的影响

为研究饲料中添加鱼油和豆油对中华绒螯蟹(Eriocheir sinensis)成蟹生长、免疫、代谢和耐低氧性能的影响,配制了添加不同比例鱼油和豆油的3种蟹用饲料,添加3%鱼油饲料组、3%豆油饲料组、3%鱼油和豆油混合组(1∶1,质量比),将其分别投喂中华绒螯蟹115 d后测量蟹体重、壳长和壳宽的变化,再将其放入溶解氧(dissolved oxygen,DO)为(9.06±0.06)mg/L和(2.57±0.44)mg/L的水体中,测定其免疫、代谢指标及耐低氧性能的变化。结果发现:投喂添加3种不同油脂饲料的中华绒螯蟹各组间体重无显著性差异;低氧胁迫对中华绒螯蟹代谢指标影响较大;添加鱼油和豆油混合油饲料组中华绒螯蟹血细胞密度、血蓝蛋白含量及超氧化物歧化酶、酸性和碱性磷酸酶、乳酸脱氢酶的活性都为最高,说明鱼油与豆油混合添加对中华绒螯蟹免疫和抗氧化能力有促进作用,并增加其耐低氧能力。