低温处理对家蚕滞育卵还原型与氧化型谷胱甘肽比值的影响

还原型谷胱甘肽(GSH)与氧化型谷胱甘肽(GSSG)的比值反映出细胞的氧化胁迫状况。利用分光光度法分别测定家蚕滞育卵持续25℃保护和经5℃低温处理后卵内谷胱甘肽代谢的变化,探讨蚕卵的谷胱甘肽代谢与滞育解除的关系。与持续25℃滞育温度条件下的蚕卵相比,5℃低温解除滞育的处理显著提高了蚕卵总谷胱甘肽含量、GSSG含量和硫氧还蛋白过氧化物酶(TPX)活性,而显著降低了GSH含量以及GSH/GSSG比值。结果表明,低温处理过程中,滞育卵TPX活性显著升高,间接地促进GSH氧化为GSSG,使GSH/GSSG比值显著下降,由此导致蚕卵处于过氧化状态。     

热胁迫对多化性家蚕5龄雌性幼虫脂肪体谷胱甘肽氧化还原循环的影响

谷胱甘肽氧化还原循环对保障机体的内环境稳定至关重要。对多化性家蚕品种兰溪10的5龄雌性幼虫连续72 h分别以常温25℃和32℃热胁迫处理,测定脂肪体中与谷胱甘肽氧化还原循环相关分子的含量和酶活性变化。在常温和热胁迫处理的雌蚕脂肪体中均检测不到谷胱甘肽过氧化物酶(GPX)活性。与常温处理组相比,热胁迫处理组的雌蚕脂肪体中还原型谷胱甘肽(GSH)含量、GSH/氧化型谷胱甘肽(GSSG)比值、谷胱甘肽S-转移酶(GST)活性和硫氧还蛋白还原酶(TrxR)活性均显著降低,H2O2、GSSG、总谷胱甘肽的含量以及硫氧还蛋白过氧化物酶(TPX)活性和TPX编码基因Bmprx的转录水平显著提高,谷胱甘肽还原酶(GR)活性和TPX的另一个编码基因Bmtpx的转录水平则无显著差异。研究结果表明,在热胁迫环境下家蚕脂肪体中的Bmprx基因被诱导上调表达,使TPX活性提高和TrxR活性降低,导致GSH/GSSG比值显著降低,谷胱甘肽氧化还原循环向氧化态转移。     

5龄期和吐丝期家蚕丝腺中的过氧化氢代谢与谷胱甘肽氧化还原循环特征

机体内的氧化还原状态对细胞的生命活动有着重要影响,而过氧化氢(H2O2)代谢和谷胱甘肽氧化还原循环与之密切相关。利用分光光度法检测5龄期和吐丝期家蚕丝腺中参与H2O2代谢与谷胱甘肽氧化还原循环调控的各种因子(氧化剂、还原剂和抗氧化剂)的含量变化。在2个时期的丝腺中未能检测到谷胱甘肽过氧化物酶(GPX)和谷胱甘肽还原酶(GR)活性。5龄期丝腺中的H2O2含量显著升高,超氧化物歧化酶(SOD)活性、氧化型谷胱甘肽(GSSG)含量、还原型谷胱甘肽(GSH)/GSSG比值变化不显著,过氧化氢酶(CAT)活性、GSH含量、总谷胱甘肽含量、硫氧还蛋白过氧化物酶(TPX)活性和硫氧还蛋白还原酶(TrxR)活性显著下降。吐丝期丝腺中的H2O2含量、SOD活性、GSH含量、GSSG含量、总谷胱甘肽含量和TPX活性显著下降,CAT活性、GSH/GSSG比值和TrxR活性显著升高。检测结果表明,5龄期丝腺中的CAT活性和TPX活性下降是导致H2O2含量升高的原因,但是TPX活性和TrxR活性下降导致的GSH/GSSG比值变化并不显著;吐丝期丝腺中的SOD活性下降导致H2O2含量下降,TPX活性下降和TrxR活性升高导致GSH/GSSG比值升高。可见,家蚕丝腺中的H2O2代谢与谷胱甘肽氧化还原循环特征在5龄期和吐丝期存在显著差异。     

二化性家蚕滞育过程中谷胱甘肽S-转移酶活性的变化

二化性家蚕卵以25℃和15℃催青,可分别诱导成虫产下子代滞育和非滞育卵,而即时浸酸和5℃左右的低温处理可以分别阻止和解除胚胎滞育。利用1-氯-2,4-二硝基苯(CDNB)显色法测定了经上述处理后的胚胎滞育过程中谷胱甘肽S-转移酶(glutathione S-transferase,GST)的活性,结果表明:胚胎发育后期的蚕卵经25℃催青,卵中的GST活性显著高于15℃催青蚕卵;蚕卵即时浸酸未显著改变胚胎滞育发动阶段蚕卵中的GST活性;5℃低温处理显著提高了滞育卵中的GST活性,但是未能显著改变即时浸酸卵的GST活性。上述结果表明,蚕卵中的GST活性变化与二化性家蚕胚胎滞育诱导和解除密切相关。     

外源一氧化氮供体SNP对NaCl胁迫下黑麦草幼苗叶片抗坏血酸-谷胱甘肽循环的影响

采用营养液栽培,研究了外源一氧化氮(NO)供体硝普钠(SNP)对150mmol/LNaCl胁迫下黑麦草幼苗叶片抗坏血酸-谷胱甘肽(ASA-GSH)循环中抗氧化酶活性和抗氧化物质及丙二醛(MDA)和H₂O₂含量的影响。结果表明,正常条件下100μmol/LSNP略微降低了黑麦草幼苗叶片的MDA和H₂O₂含量,NO信号转导途径关键酶鸟苷酸环化酶(GC)抑制剂亚甲基蓝(MB)促进了MDA和H₂O₂水平的提高。NaCl胁迫下,SNP显著缓解了MDA和H₂O₂的积累,提高了抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)和脱氢抗坏血酸还原酶(DHAR)活性及还原型抗坏血酸(ASA)、谷胱甘肽(GSH)含量,降低脱氢抗坏血酸(DHA)和氧化型谷胱甘肽(GSSG)含量,使ASA/DHA和GSH/GSSG提高,却对单脱氢抗坏血酸还原酶(MDAR)活性无显著影响;MB逆转了SNP对NaCl胁迫下MDA、H₂O₂、ASA、GSH、DHA、GSSG含量和APX、GR活性及ASA/DHA和GSH/GSSG的调节作用,对MDAR和DHAR活性无显著影响。由此表明,NO可能通过GC介导参与盐胁迫下黑麦草叶片ASA-GSH循环中APX、GR活性和ASA、GSH含量及ASA/DHA、GSH/GSSH的调节,缓解盐胁迫诱导的氧化伤害,提高植株的耐盐性。     

二化性家蚕滞育发动期间滞育性卵和非滞育性卵的烟酰胺腺嘌呤二核苷酸变化

为了探究家蚕滞育发动期间呼吸耗氧量下降与烟酰胺腺嘌呤二核苷酸(NAD)含量变化的关系,用高效液相色谱法和分光光度法分别检测在25℃条件下产下后12～72 h的二化性家蚕滞育性卵与非滞育性卵中的还原型NAD(NADH)含量、氧化型NAD(NAD+)含量、乳酸脱氢酶(LDH)活性和胞质苹果酸脱氢酶(cMDH)活性。滞育性卵中的NADH+NAD+含量、NADH/NAD+值及LDH活性分别在产下后18、36、24 h达到峰值,而cMDH活性处于波动中。在产下后24～72 h,非滞育性卵中的NADH/NAD+值极显著低于滞育性卵,而LDH和cMDH活性极显著高于滞育性卵。据此可以推测,滞育发动期间家蚕滞育性卵的NAD+降解增强和NAD+再生下降共同导致呼吸耗氧量下降。     

家蚕滞育卵中辅酶Ⅰ和辅酶Ⅱ的含量变化

利用苹果酸脱氢酶(MDH)和柠檬酸合酶(CS)串联反应以及葡萄糖-6-磷酸脱氢酶(G6PDH)催化葡萄糖-6-磷酸(G-6-P)脱氢反应,分别测定了家蚕滞育发动、即时浸酸和低温冷藏处理蚕卵辅酶Ⅰ(NAD+)和辅酶Ⅱ(NADP+)的含量。滞育发动时蚕卵NAD+含量显著下降,而即时浸酸和低温冷藏处理使蚕卵NAD+含量显著提高。蚕卵中的NADP+在滞育发动前大量积累,滞育发动时下降,即时浸酸处理后NADP+含量显著提高,在低温冷藏早期其含量进一步提高,低温冷藏处理后期又显著下降。分析上述结果认为,家蚕滞育卵中NAD+和NADP+含量的变化分别与呼吸耗氧量和糖元-山梨醇相互转化密切相关。     

GSH对铅胁迫下多年生黑麦草幼苗抗氧化系统的调控

本试验以12周龄的多年生黑麦草（Lolium perenne ‘cuttle’）幼苗为试验材料,用铅（Lead,Pb）,Pb+还原型谷胱甘肽（Glutathione,GSH）和Pb+丁硫氨酸-亚砜亚胺（L-Buthionine-sulfoximine,BSO）处理1周,研究GSH对Pb胁迫下多年生黑麦草抗氧化系统的调控机理,寻求缓解植物Pb胁迫的有效措施。结果表明：Pb胁迫下,外源GSH能够显著提高多年生黑麦草Pb的吸收和转运,增加抗氧化酶超氧化物歧化酶（Superoxide dismutase,SOD）、谷胱甘肽过氧化物酶（Glutathione peroxidase,GPX）和谷胱甘肽还原酶（Glutathione reductase,GR）活性,显著增加抗氧化剂GSH含量及GSH/氧化型谷胱甘肽（Oxidized glutathione,GSSG）比率,提高了植物的还原力。外源GSH也能够显著降低活性氧超氧阴离子（Superoxide anion,O₂^·-）和过氧化氢（Hydrogen peroxide,H₂O₂）的产生量、膜的相对透性（Relative electric conductivity,EC）和丙二醛（Malondialdehyde,MDA）含量,保持了细胞的稳定性,减轻了膜脂的过氧化程度。外源BSO作用基本上与GSH相反。相关分析表明：GSH可通过提高SOD和GPX等抗氧化酶的活性,促进GSSG和GSH的相互转化,降低活性氧产生量,提高植物抵抗逆境胁迫的能力。     

马尾藻多糖对鸡脾脏淋巴细胞GSH和GSSG水平的影响

为观察马尾藻多糖(SP)对鸡脾脏淋巴细胞内氧化还原状态的影响,无菌分离鸡脾脏淋巴细胞,采用终浓度为12.5、25、50、100、200μg/mL的马尾藻多糖分别刺激培养鸡脾脏淋巴细胞4、8、12、24h,测定细胞内还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)水平。结果表明,各浓度SP与鸡脾脏淋巴细胞共同培养4、8、12h均能不同程度地升高细胞内GSH水平,降低鸡脾脏淋巴细胞内GSSG水平,升高鸡脾脏淋巴细胞内GSH/GSSG比值,与空白对照组相比差异显著或极显著(P0.05或P0.01)。说明SP可以通过调节鸡脾脏淋巴细胞内GSH和GSSG的水平来调节细胞内的氧化还原状态,从而发挥其抗氧化作用。     

家蚕氟化物中毒后血淋巴中脂质过氧化物和抗氧化物含量及抗氧化酶活性的变化

为了探究氟化物对家蚕的毒理作用,通过给家蚕5龄期幼虫添食NaF,检测氟化物中毒家蚕幼虫血淋巴中脂质过氧化物质丙二醛(MDA)、抗氧化物质谷胱甘肽(GSH)的含量变化以及谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽硫转移酶(GST)等抗氧化物酶的活性变化。正常家蚕幼虫和氟化物中毒家蚕幼虫血淋巴中的MDA含量在5龄期均逐渐下降,但氟化物中毒家蚕的MDA平均浓度比正常家蚕升高了83.77%;GSH含量变化趋势为5龄第1天和第5天较高,第3天较低,但氟化物中毒家蚕5龄期的GSH浓度平均比正常家蚕下降了47.81%;氟化物中毒家蚕5龄期的GSH-Px和GST的平均活性分别比正常家蚕升高63.49%、39.22%,5龄第3天达到最高峰,5龄第1天和第5天较弱。初步分析认为家蚕幼虫血淋巴中MDA和GSH的含量变化以及GSH-Px和GST的活性变化,与家蚕氟化物中毒后体内氧自由基含量上升和脂质过氧化作用增强密切相关,可作为诊断家蚕氟化物中毒的生化指标。     

Ontogeny of glutathione and glutathione-related antioxidant enzymes in rat liver

We conducted a comprehensive characterization of the ontogeny of glutathione (GSH) and its related enzymes in rat liver. GSH content and activities of glutathione reductase (GR), cytosolic glutathione-S-transferases (GST), and glutathione peroxidase (GPx) were determined in male rat livers (n = 4) at different developmental stages. Our results indicate total hepatic GSH content and GR, GST, and GPx activity were low in the perinatal period. GSH content remained relatively constant throughout postnatal development, but GR, GST, and GPx activity underwent significant increases to attain adult levels by late post-weaning. Whether the ontogenic pattern of GSH and its related enzymes explain, in part, the altered susceptibility of neonates to some toxicants requires further investigation. Our study provides fundamental biological information on the ontogeny of cytosolic antioxidant/detoxification enzymes in a relevant toxicological risk assessment species. Additional studies are needed to fully characterize the ontogeny of other xenobiotic detoxification enzymes to further promote the rat as a developmental toxicology model that can identify toxicokinetic reasons for differences in susceptibility to toxicity between the neonate and adult.     

3-氨基三唑与过氧化氢共同处理对家蚕滞育发动的影响

研究有效阻止家蚕滞育发动的措施发现 :在家蚕滞育发动期间 ,仅用过氧化氢酶 (catalase ,CAT)的专一性抑制剂 3 氨基三唑 (3 amino 1,2 ,4 triazole ,AT)处理滞育性蚕卵仍不能阻止家蚕滞育发动 ;但先用AT处理抑制CAT活性后 ,再用H2 O2 处理可有效阻止家蚕滞育发动。     

SO2对家蚕血淋巴中谷胱甘肽含量及相关酶活性的影响

通过分析在SO2胁迫下家蚕5龄幼虫血淋巴中谷胱甘肽(GSH)含量及相关酶活性的变化,探讨SO2对家蚕的毒理作用机制。当对家蚕5龄幼虫每天以40 mg/m3SO2熏气刺激6 h,蚕体血淋巴中的GSH含量显著降低,雄蚕GSH的平均含量为49.8μmol/L,雌蚕为41.0μmol/L,分别为对照的73.80%和55.76%,而谷胱甘肽硫-转移酶(GST)活性显著升高,雄蚕GST的平均活性为31.86 U/L,雌蚕为31.80 U/L,分别高于对照46.15%和27.30%。与此同时,γ-谷氨酰转肽酶(γ-GT)活性在蚕体中也有不同程度的升高,其中在雄蚕体内的变化极为显著;谷胱甘肽过氧化酶(GSH-Px)和谷胱甘肽合成酶系的活性在蚕体内均无显著变化。以上结果表明:SO2刺激可对家蚕血淋巴中的GSH含量及其相关酶的活性产生影响,且雌、雄蚕对SO2的敏感性不同;GSH含量的减少及其相关酶活性的上升,说明SO2对蚕体的毒害作用与其降低蚕体抗氧化物质水平、削弱抗氧化防御系统有关。     

Blood glutathione status and activity of glutathione‐metabolizing antioxidant enzymes in erythrocytes of young trotters in basic training

The aim of this study was to evaluate response of blood glutathione status and activity of glutathione‐metabolizing antioxidant enzymes in erythrocytes of young trotters in basic training. Nine untrained trotters (aged 16–20 months) were exposed to a 4‐month training program based on exercises at low‐to‐moderate intensity. The conditioning consisted of breaking the horses and running them on distances varying from 4 to 40 km a week. The workloads were increased on a 3‐week basis. Exercise intensity was monitored by measuring heart rate and blood lactate. Blood samples were collected at rest, before (RES0) and after (RESt) the conditioning period; moreover, on the latter occasion (on day 112 of training), the blood was also taken immediately after the routine exercise (EXE0) and 60 min thereafter (EXE60). The whole blood samples were analysed for the concentration of reduced, oxidized and total glutathione (GSH, GSSG and TGSH, respectively), while the activities of glutathione peroxidase (GPX) and glutathione‐disulfide reductase (GR) were determined in haemolysates. Additionally, the erythrocytic concentrations of oxidized nicotinamide adenine dinucleotide (NAD⁺) and its phosphate (NADP⁺) were measured. All investigated parameters except NAD⁺ and reduced/oxidized glutathione ratio (GSH/GSSG) changed during the training period. Following the effortm GPX, NADP⁺ and GSH/GSSG were significantly lower (p < 0.05, p < 0.01, p < 0.001, respectively) while GSSG was markedly higher than at rest (RESt). The drop in NADP⁺, low GSH/GSSG and high GSSG concentration were sustained at EXE60. Glutathione‐disulfide reductase activity was higher after the workout but only at EXE60 the increase in activity was significant. Despite the activities of the GSH‐GSSG cycle, enzymes were considerably higher after the training period, the elevated concentration of GSSG and significantly lower GSH/GSSG ratio in the post‐exercise measurements suggest that production of reactive oxygen species possibly exceeds the capacity of antioxidative defenses of immature trotters. A more balanced diet with additional antioxidant supplementation and a revision of the basic training protocol used herein are advised.     

Antioxidant defence system of boar cauda epididymidal spermatozoa and reproductive tract fluids

Antioxidants secreted by the reproductive tract protect spermatozoa against the toxic effects of reactive oxygen species (ROS) after ejaculation. This study aimed at characterizing the level of antioxidant protection in boar cauda epididymidal spermatozoa and fluids of the cauda epididymidis, vesicular and prostate glands. Also, this study investigated the effect of a 5-h period of dialysis on the antioxidant capacity of boar seminal plasma. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GST) and phospholipid hydroperoxide glutathione peroxidase (PHGPx) activities were monitored in the cauda epididymidal spermatozoa or reproductive tract fluids. Also, the concentrations of total glutathione (GSH + GSSG), L-ergothioneine (ERT) and l-ascorbate and the total antioxidant status (TAS) of the fluids were measured. It was found that the cauda epididymidal spermatozoa exhibited high SOD activity and relatively low activity of PHGPx. The relative amounts of GPx, GR and GST activities in the cauda epididymidal spermatozoa were negligible, whereas CAT activity was undetectable. Greater SOD activity was found in the fluids of the cauda epididymidis and prostate gland. Furthermore, the prostate gland fluid appeared to be the main source of CAT activity in the seminal plasma, whereas the highest level of GPx activity was derived from the cauda epididymidal fluid. The reproductive tract fluids exhibited negligible amounts of GR and GST activities. It seemed that the significant amounts of GSH + GSSG, ERT and L-ascorbate in the reproductive tract fluids could have an ameliorative effect on the level of TAS in the seminal plasma. Dialysis had a marked effect on the total antioxidant capacity of the seminal plasma, which was manifested in greater activity of SOD and GPx. The findings of this study confirmed that the scavenging potential of the seminal plasma is dependent on the contributions of different antioxidants, originating in various fluids of boar reproductive tract.     

合成滞育激素对家蚕卵Gpase、NAD-SDH、PFK、FBP活性的影响

二化性蚕品种大造在高温（25℃）明条件（每日光照18小时）下催青时,全部产滞育卵,在低温（16℃）暗条件（全天黑暗）下催青时全部产非滞育卵。低温暗条件下催青的大造在化蛹第3日注射一定剂量的合成滞育激素,可以诱导其产下70％左右左右的滞育卵。这种由合成滞育激素诱导形成的滞育卵,在滞育期中Gpase,PFK,FBP,NAD-SDH等与碳水化合物代谢相关的酶活性与非滞育卵不同,,但与天然滞育卵相似。只是酶活性和蚕卵解除滞育的时间比天然滞育卵有所提高。