,2, 吕加平,1Chromium (III) Stress Alleviation by Sulfur Compounds During Chromium Bio-enrichment by Saccharomyces cerevisiae
LI HanTong1, JIA ChengLi1, ZHANG ShuWen1, LU Jing1, PANG XiaoYang1, LIU Lu,2, Lü JiaPing,1通讯作者:
责任编辑: 赵伶俐
收稿日期:2018-09-14接受日期:2019-01-11网络出版日期:2019-03-16
| 基金资助: |
Received:2018-09-14Accepted:2019-01-11Online:2019-03-16
作者简介 About authors
李函彤,Tel：17526505132;E-mail： hantongl2011@163.com。
摘要
关键词：
Abstract
Keywords：
PDF (445KB)元数据多维度评价相关文章导出EndNote|Ris|Bibtex收藏本文
本文引用格式
李函彤, 甲承立, 张书文, 芦晶, 逄晓阳, 刘鹭, 吕加平. 硫对酵母生物富铬过程中铬胁迫的缓解作用[J]. 中国农业科学, 2019, 52(6): 1078-1089 doi:10.3864/j.issn.0578-1752.2019.06.011
LI HanTong, JIA ChengLi, ZHANG ShuWen, LU Jing, PANG XiaoYang, LIU Lu, Lü JiaPing.
0 引言
【研究意义】作为人体必需的微量元素,Cr（Ⅲ）可以促进机体葡萄糖代谢,降低甘油三酯和游离脂肪酸含量,维持体内糖脂代谢平衡[1]。酵母可以通过生物吸附和转化作用将环境中的无机铬转化为有机铬。这种来源于酵母的有机铬也被称为葡萄糖耐量因子（glucose tolerance factor,GTF）[2,3,4],它具有吸收率高、安全性高的特点,被认为是最安全的铬补充剂[5]。但作为重金属,Cr（Ⅲ）对酵母的生长有两面性。一方面,低浓度的铬可促进酵母的生长;另一方面,高浓度的铬可对酵母生长造成一定的氧化胁迫作用,抑制酵母的正常生命活动、生长和GTF的生成。因此,研究酿酒酵母在富集Cr（Ⅲ）形成葡萄糖耐量因子（GTF）过程中自身抗氧化机制以及硫在该过程中发挥的作用,对揭示硫降低铬胁迫,进而提高生物富铬的作用机理具有重要意义。【前人研究进展】环境中的氧化还原剂或重金属等能刺激细胞产生超氧负离子、羟基和过氧化氢等内源性活性氧族物质（reactive oxygen species,ROS）等代谢产物。这些代谢产物在细胞中累积到一定程度,可对DNA、脂质和蛋白质等细胞组分造成一定的损害,进而影响细胞的功能甚至造成细胞死亡[6]。研究发现,高浓度Cu2+会对酵母造成胁迫作用[7,8],铜是氧化还原反应的活泼因子,参与Fenton反应[9],产生有害的氢氧根离子[10],氢氧根离子可引起细胞膜脂质、蛋白质的氧化以及DNA和RNA分子的解链,导致细胞的死亡[11]。重金属会对生物造成氧化应激,破坏DNA结构,抑制酶的功能,破坏蛋白质在细胞增殖、细胞周期、细胞凋亡和变异过程中的作用[12,13]。据报道,Cd（Ⅱ）、As（Ⅲ）和Cr（Ⅵ）可以在酵母中产生ROS,诱导酵母体内氧化应激和脂质过氧化反应从而造成酵母细胞损伤[14,15,16]。有研究表明,Cr（Ⅲ）容易与酵母中DNA和其他生物组分形成稳定的胞内配体,特别是与抗坏血酸盐、组氨酸、谷胱甘肽、半胱氨酸等[17]。刘鹭等[18]研究发现,培养液中高浓度Cr（Ⅲ）（800 μg?mL-1）严重抑制菌体生长;而低浓度的Cr（Ⅲ）（200—400 μg?mL-1）对菌体的生长具有轻微刺激作用,但有机铬富集率较低。高氧化价态的金属在硫的作用下可以转变为低价态[19],硫的补充可以降低Cr（Ⅵ）对于酵母细胞的毒性,促进酵母对废水液中Cr（Ⅵ）的吸收[20]。【本研究切入点】关于Cr（Ⅲ）对酵母在生成GTF过程中产生的氧化胁迫作用鲜有报道,而针对缓解铬的氧化胁迫作用、提高酵母富铬含量的研究更少。本研究利用前期转录组学结果对比分析了富铬酵母和对照酵母的差异基因及其代谢通路,发现酵母富铬过程与硫代谢和GSH代谢通路有密切的关系。基于以往文献报道硫吸收和GSH生物合成相互联系,并在缓解重金属Cr（Ⅵ）对微生物的胁迫时发挥了重要的作用[21],本研究拟在富铬酵母发酵过程中添加不同种类的硫化合物,对比观察富铬酵母的生长,包括富集有机铬、总铬以及体内氧化应激的变化。【拟解决的关键问题】基于转录组学对酵母富铬代谢通路的分析结果,研究不同种类的硫对酵母富铬以及体内氧化应激的影响,揭示硫对Cr（Ⅲ）胁迫下酵母生物富铬调节机制,为酵母生物富集铬生成GTF的发酵条件优化提供理论依据。1 材料与方法
1.1 试验材料
试验菌株和对照菌株均为酿酒酵母YSI-3.7,保藏于中国普通微生物菌种保藏管理中心（CGMCC No. 2687）。YPD培养基（大豆蛋白胨20 g,葡萄糖20 g,酵母浸粉10 g,蒸馏水1 L,pH 5.8,121℃,灭菌15 min）的大豆蛋白胨和酵母浸粉,北京奥 博星生物技术公司;葡萄糖、无水亚硫酸钠、硫化钠,国药集团;硝酸、氨水和高氯酸,上海晶纯科技公司;三氯化铬（Ⅲ）六水化合物,上海阿拉丁公司。1.2 试验设计
以高产GTF的YSI-3.7为出发菌株,研究和分析不同浓度（0、200、500和800 μg?mL-1）Cr（Ⅲ）对酵母富集Cr（Ⅲ）情况及氧化应激的影响,寻找酵母培养最适Cr（Ⅲ）浓度;在最适Cr（Ⅲ）浓度条件下（500 μg?mL-1）,对比研究不同种类硫化合物（Na2SO3、Na2S、（NH4）2SO3）对缓解Cr（Ⅲ）胁迫的氧化应激的影响;在最适硫化合物及浓度下（1 mmol?L-1Na2SO3）,测定酵母菌体生物量、丙二醛（MDA）、超氧化物歧化酶（SOD）、过氧化物酶（CAT）、还原型谷胱甘肽（GSH）、氧化型谷胱甘肽（GSSG）、谷胱甘肽氧化酶（GSH-PX）、总巯基、总抗氧化能力（T-AOC）等参数,探讨硫对Cr（Ⅲ）胁迫下酵母生物富铬调节机制。1.3 方法
1.3.1 富铬酵母YSI-3.7培养 将通过梯度铬平板（200、500、800和1 000 μg?mL-1 Cr（Ⅲ）筛选出的富铬能力最强、生物量最大的酿酒酵母YSI-3.7单菌落（有机铬含量1 033.91 μg?g-1 DCW,总铬含量1 603.87 μg?g-1 DCW,生物量1.041 g/100 mL YPD）接种于YPD培养基中培养至第3代,然后以10%（v/v）接种量分别接种于含有一定铬浓度的YPD培养基中,于恒温培养振荡器中28℃、200 r/min摇瓶培养44 h。于4℃、6 000 r/min离心10 min收集菌体,用无菌水洗涤3次,称其湿重;-60℃冷冻干燥48 h得到冻干菌粉。1.3.2 有机铬、总铬含量的测定 参考火焰原子吸收法[22]。
1.3.2.1 富铬酵母菌体中有机铬测定 富铬酵母中有机铬可溶于氨水,称取0.1 g冻干酵母菌粉溶于10 mL 0.1 mol?L-1氨水溶液中,于37℃、200 r/min提取3 h。于4℃、5 000 r/min离心10 min,收集上清液于溶样杯中,加入6 mL浓硝酸。将其置于加热板于160℃预加热30 min,再加入0.5 mL高氯酸和5 mL 5%（m/v）的过硫酸铵,进行微波消解,参数如表1所示。消解完全后用10% NH4Cl溶液定容至25 mL,参照GB/T15555.6—1995火焰原子吸收光谱法测定消化液中铬含量,即为富铬酵母菌体中有机铬的含量。
Table 1
表1
表1Cr（Ⅲ）对酵母YSI-3.7生物量及生物富铬的影响
Table 1
| Cr（Ⅲ） (μg?mL-1) | ||||
|---|---|---|---|---|
| 0 | 200 | 500 | 800 | |
| 生物量 Biomass (g/100 mL) | 1.40±0.07 | 1.06±0.01 | 0.97±0.05 | 0.45±0.02 |
| 有机铬 Organic chromium (μg·g-1DCW) | 0 | 224.74±6.41 | 725.55±55.08 | 536.25±36.89 |
| 总铬 Total chromium (μg·g-1DCW) | 0 | 409.04±12.65 | 1255.53±43.75 | 1812.22±38.24 |
| 有机铬/总铬 Organic/total chromium (%) | 0 | 54.94±1.90 | 57.79±2.45 | 29.59±2.48 |
新窗口打开|下载CSV
1.3.2.2 富铬酵母菌体总铬测定 直接称取0.1 g冻干菌粉于溶样杯中,加入6 mL浓硝酸。将其置于加热板于160℃预加热30 min,再加入0.5 mL高氯酸和5 mL 5%（m/v）的过硫酸铵,进行微波消解,微波消解参数设置如表1所示。消解完全后用10% NH4Cl溶液定容至25 mL,参照GB/T15555.6—1995火焰原子吸收光谱法测定消化液中铬含量,即为富铬酵母菌体的总铬含量。
1.3.3 相关生理指标的测定
1.3.3.1 丙二醛（MDA）含量 取菌体破壁、离心后的上清液,按照丙二醛（MDA）测试盒说明书步骤进行。
1.3.3.2 超氧化物歧化酶（SOD）活力 取菌体破壁、离心后的上清液,按照超氧化物歧化酶（SOD）测定试剂盒说明书步骤进行。
1.3.3.3 过氧化氢酶（CAT） 取菌体破壁、离心后的上清液,按照过氧化氢酶（CAT）测定试剂盒说明书步骤进行。
1.3.3.4 谷胱甘肽（GSH,GSSG） 取菌体破壁、离心后的上清液,按照GSH和GSSG检测试剂盒说明书步骤进行。
1.3.3.5 总抗氧化能力（T-AOC） 取菌体破壁、离心后的上清液,按照T-AOC检测试剂盒说明书步骤进行。
1.3.3.6 总巯基 取菌体破壁、离心后的上清液,按照巯基检测试剂盒说明书步骤进行。
1.3.3.7 谷胱甘肽过氧化物酶（GSH-Px） 取菌体破壁、离心后的上清液,按照谷胱甘肽检测试剂盒说明书步骤进行。
1.4 数据分析
应用SPSS16.0对所有数据进行统计分析和绘图。2 结果
2.1 Cr（Ⅲ）胁迫对酵母YSI-3.7生物富铬及氧化应激影响
2.1.1 生物量及富铬情况 随着培养液中Cr（Ⅲ）浓度的升高,YSI-3.7菌体富集铬的总量升高（包括有机铬和总铬）,生物量下降。与对照组（Cr（Ⅲ）浓度为0）酵母相比,200、500和800 μg?mL-1 Cr（Ⅲ）浓度下酵母生物量分别降低24.29%、30.71%和67.86%。在500 μg?mL-1 Cr（Ⅲ）浓度下,酵母中的有机铬含量达到725.55 μg·g-1 DCW,有机铬率最高,达到57.79%;酵母于800 μg?mL-1 Cr（Ⅲ）浓度下虽然吸附的总铬高至1 812.22 μg?mL-1,但生物量降低较为严重,并且有机铬率仅为29.59%（表1）。综合考虑菌体生物量以及富集铬的情况,Cr（Ⅲ）浓度为500 μg?mL-1为酵母发酵富铬最佳浓度。2.1.2 Cr（Ⅲ）胁迫对酵母YSI-3.7氧化应激影响 通过研究Cr（Ⅲ）胁迫对酵母YSI-3.7各氧化应激指标的影响可知（表2）,酵母细胞中丙二醛（MDA）的含量随着培养基中Cr（Ⅲ）浓度的增加而增加。MDA的量可以反映酵母细胞内脂质过氧化的程度,间接地反映出细胞损伤的程度。200、500和800 μg?mL-1铬浓度下,丙二醛含量分别比对照组增加31.36%、42.94%和52.49%。
Table 2
表2
表2Cr（Ⅲ） 对酵母细胞氧化应激的影响
Table 2
| 检测指标 Index | Cr（Ⅲ） 浓度 Cr（Ⅲ） concentration (μg?mL-1) | |||
|---|---|---|---|---|
| 0 | 200 | 500 | 800 | |
| 丙二醛 MDA (nmol?mL-1) | 11.83±0.38 | 15.54±0.41 | 16.91±0.33 | 18.04±0.44 |
| 超氧化物岐化酶 SOD (U?mg-1 prot) | 8.61±0.19 | 8.28±0.11 | 7.93±0.07 | 7.35±0.21 |
| 过氧化氢酶 CAT (U?mg-1 prot) | 9.09±0.28 | 7.83±0.14 | 4.72±0.09 | 3.64±0.03 |
| 还原型谷胱甘肽 GSH (μmol?g-1 prot) | 31.42±1.54 | 40.22±1.38 | 48.52±2.01 | 43.84±1.94 |
| 氧化型谷胱甘肽 GSSG (μmol?g-1 prot) | 7.86±0.21 | 9.56±0.32 | 12.38±0.52 | 15.46±0.61 |
| 谷胱甘肽氧化酶 GSH-Px (U?g-1 prot) | 1044.51±10.22 | 1274.32±5.89 | 763.01±3.21 | 534.68±6.76 |
| 总巯基 -SH (μg?g-1 prot) | 38.51±1.14 | 53.44±2.71 | 59.05±2.98 | 35.74±1.97 |
| 总抗氧化能力 T-AOC (U?g-1 prot) | 0.8±0.21 | 0.85±0.19 | 1.61±0.32 | 0.35±0.01 |
新窗口打开|下载CSV
随着Cr（Ⅲ）浓度升高,YSI-3.7中SOD活力略有下降,在200、500和800 μg?mL-1 Cr（Ⅲ）浓度下,分别比对照组下降3.83%、7.90%和14.63%。在对照酵母中,CAT的活力可达到9.09 U?mg-1 prot,随着Cr（Ⅲ）浓度升高,CAT活力有所下降,在200、500和800 μg?mL-1 Cr（Ⅲ）浓度下,分别比对照组下降13.86%、48.07%和59.96%。
在对照酵母中,还原型谷胱甘肽（GSH）含量随着Cr（Ⅲ）浓度升高,呈现先增加后减少趋势,GSH含量于500 μg?mL-1 Cr（Ⅲ） 浓度下达到最高48.52 μmol·g-1 prot。在200、500和800 μg?mL-1 Cr（Ⅲ） 浓度下,分别比对照组增加28.01%、54.42%和39.53%。与GSH变化趋势不同,氧化型谷胱甘肽（GSSG）含量随着Cr（Ⅲ）浓度的升高而升高,在Cr（Ⅲ）浓度为800 μg?mL-1时含量达到最高,为15.46 μmol·g-1 prot,比对照组增加96.69%。在Cr（Ⅲ）浓度为200、500 μg?mL-1时,GSSG的含量也高于对照组,分别增加21.63%和57.51%。GSH/GSSG通常用来表示生物体的抗氧化能力。GSH/GSSG的比值在对照组中为4,在Cr（Ⅲ）浓度为200、500和800 μg?mL-1时分别为4.21、3.92和2.84。
Cr（Ⅲ）添加浓度为200和500 μg?mL-1时,培养基中巯基含量分别比对照组提高38.77%和53.34%。在800 μg?mL-1 Cr（Ⅲ）浓度下,巯基含量相对于对照组酵母降低约7.19%。酵母细胞中总抗氧化能力(T-AOC)于0—500 μg?mL-1 Cr（Ⅲ）浓度下持续升高。当Cr（Ⅲ）浓度继续升高至800 μg?mL-1时,T-AOC比对照降低56.25%。培养基中Cr（Ⅲ）浓度从0升高到500 μg?mL-1时,酵母细胞中T-AOC持续升高,说明在此浓度范围内,Cr（Ⅲ）胁迫使酵母细胞的抗氧化能力提高,而当Cr（Ⅲ）浓度升高至800 μg?mL-1时,酵母细胞的抗氧化能力降低,并且远低于对照组。说明高Cr（Ⅲ）对酵母造成了很大的破坏作用,酵母自身的抗氧化能力已经不足以应对此浓度下Cr（Ⅲ）的氧化胁迫。
2.2 不同硫化合物对铬胁迫下酵母YSI-3.7生物量及生物富铬的影响
由表3可以看出,培养基中添加不同硫酸盐培养的酵母细胞生物量（干重）几乎均随着其浓度的增加而减少。其中有机铬含量随着培养基中添加Na2SO3、Na2S、（NH4）2SO3浓度的升高先增加后减少,并分别在浓度5、1和1 mmol?L-1时达到最大值。对于培养基中添加Na2SO3和（NH4）2SO3的酵母而言,酵母中总铬含量随着亚硫酸盐添加浓度的升高先增加后减少,分别在5、15 mmol?L-1时达到最大值。而对于添加Na2S的酵母,其总铬的含量在0.5—15 mmol?L-1浓度持续增加。对于培养基中添加Na2SO3、Na2S的酵母,其有机铬率均先上升后下降,且均在浓度为1 mmol?L-1时达到最大值,分别为对照的85.65%和67.75%。而对于添加（NH4）2SO3后发酵的酵母,其有机铬率随着其浓度升高而下降。结合细胞干重、有机铬、总铬、有机铬率等指标,当在培养基中添加1 mmol?L-1 Na2SO3时,对于酵母富集Cr（Ⅲ）形成有机铬最有利。此时,酵母细胞生物量为只添加500 μg?mL-1 Cr（Ⅲ）的84.83%,总铬含量提高31.03%,有机铬率提高32.88%。综上,选择1 mmol?L-1 Na2SO3进行后续研究。Table 3
表3
表3硫化合物对酿酒酵母YSI-3.7生物量及生物富铬的影响
Table 3
| 含硫化合物 S compound | 浓度 Concentration (mmol?L-1) | 生物量 Biomass (g/100 mL) | 有机铬 Organic chromium (μg·g-1·DCW) | 总铬 Total chromium (μg·g-1·DCW) | 有机铬率 Percentage of organic chromium (%) |
|---|---|---|---|---|---|
| 0 | 对照组 Control | 1.002±0.1 | 755.63±4.23 | 1431.93±10.12 | 52.77±1.24 |
| Na2SO3 | 0.5 | 0.92±0.07 | 1198.16±9.43 | 1578.21±11.27 | 75.92±3.75 |
| 1 | 0.85±0.08 | 1607.02±6.78 | 1876.32±9.43 | 85.65±2.36 | |
| 5 | 0.60±0.04 | 2052.43±10.58 | 2755.04±11.38 | 74.50±3.57 | |
| 10 | 0.49±0.03 | 609.58±4.98 | 1746.95±8.79 | 34.84±1.98 | |
| 15 | 0.32±0.02 | 477.39±2.75 | 740.18±8.02 | 64.50±1.63 | |
| Na2S | 0.5 | 1.005±0.25 | 895.98±5.72 | 1601.45±5.98 | 55.95±1.48 |
| 1 | 1.08±0.07 | 1261.16±6.27 | 1868.74±9.98 | 67.75±2.32 | |
| 5 | 0.781±0.03 | 691.63±3.61 | 2302.31±11.54 | 30.04±1.03 | |
| 10 | 0.69±0.08 | 613.83±2.88 | 3516.62±21.32 | 17.46±0.98 | |
| 15 | 0.15±0.04 | 318.70±1.02 | 3834.02±20.98 | 8.31±0.45 | |
| （NH4）2SO3 | 0.5 | 0.996±0.05 | 721.01±2.79 | 2101.45±14.32 | 34.31±1.74 |
| 1 | 0.942±0.04 | 861.12±5.97 | 2868.14±16.45 | 30.02±1.05 | |
| 5 | 0.276±0.02 | 542.19±4.34 | 3000.21±18.91 | 18.07±1.13 | |
| 10 | 0.121±0.02 | 301.21±2.83 | 1812.62±13.69 | 16.62±0.45 | |
| 15 | 0.085±0.01 | 100.32±1.56 | 1367.02±9.13 | 7.33±0.41 |
新窗口打开|下载CSV
2.3 Na2SO3对酵母YSI-3.7富铬及铬胁迫下氧化应激的影响
2.3.1 对应激代谢产物的影响 氧自由基能攻击生物膜中的多不饱和脂肪酸,引发脂质过氧化作用,形成脂质过氧化物,如丙二醛。MDA的量可以反映酵母细胞内脂质过氧化的程度,间接地反映出细胞损伤的程度。如图1-A所示,500 μg?mL-1 Cr（Ⅲ）处理的酵母体内MDA含量为16.91 nmol?mL-1,相比于空白组,提高了24.60%;1 mmol?L-1 Na2SO3可有效降低因Cr（Ⅲ）引起的MDA含量,相比于500 μg?mL-1 Cr（Ⅲ）处理组,MDA含量降低了12.8%。图1
新窗口打开|下载原图ZIP|生成PPT图1Na2SO3对铬胁迫下酵母氧化应激代谢产物的影响
0：Cr（Ⅲ）浓度为0（空白对照组）;500：Cr（Ⅲ） 浓度为500 μg?mL-1;500+1S: Cr（Ⅲ） 浓度为500 μg?mL-1,Na2SO3浓度为1 mmol?L-1。下同
Fig. 1Effects of Na2SO3 on reactive oxygen species related intermediate metabolites by YSI-3.7
0: Chromium (Ⅲ) concentration is 0. 500: Chromium (Ⅲ) concentration is 500 μg?mL-1. 500+1 NS: Chromium (Ⅲ) concentration is 500 μg?mL-1, Na2SO3 concentration is 1 mmol?L-1. The same as below
如图1-B所示,500 μg?mL-1 Cr（Ⅲ）处理的酵母体内巯基含量为59.05 μg?g-1 prot;1 mmol?L-1 Na2SO3可促进富铬酵母体内巯基含量的增加,达到65.51 μg?g-1 prot;相比于500 μg?mL-1 Cr（Ⅲ）处理组,巯基含量提高了16.87%。
如图1-C所示,500 μg?mL-1 Cr（Ⅲ）处理的酵母细胞内还原型谷胱甘肽（GSH）含量为48.52 μmol?g-1 prot,相比于对照酵母组增加了54.42%。1 mmol?L-1 Na2SO3可促进富铬酵母体内GSH增加至62.51 μmol?g-1 prot。相比于空白组和500 μg?mL-1 Cr（Ⅲ）处理组分别提高98.95%和28.83%。
如图1-D所示,500 μg?mL-1 Cr（Ⅲ）处理的酵母体内氧化型谷胱甘肽（GSSG）含量为12.38 μmol?g-1 prot,相比于空白酵母组增加57.71%。1 mmol?L-1 Na2SO3可促进富铬酵母体内GSSG降低至7.85 μmol?g-1 prot。相较于500 μg?mL-1 Cr（Ⅲ）处理组,GSSG降低了57.71%,与空白组酵母体内GSSG含量近似。
2.3.2 对酵母抗氧化能力的影响 金属离子的氧化胁迫会激活微生物机体自身抗氧化保护酶系统,消除自由基,维持体内自由基动态平衡[23]。如图2-A所示,500 μg?mL-1 Cr（Ⅲ）处理的酵母体内SOD含量为7.93 U?mg-1 prot,相比于空白酵母组降低7.9%。1 mmol?L-1 Na2SO3可促进富铬酵母体内SOD增加至8.28 U?mg-1 prot,比500 μg?mL-1 Cr（Ⅲ）单独处理组提高4.41%。空白对照组中酵母的CAT的活力达到9.09 U?mg-1·prot;其他两组处理相比,酵母细胞中CAT活力无显著变化（图2-B）,表明硫的添加对SOD、CAT的活力提高不明显。
图2
新窗口打开|下载原图ZIP|生成PPT图2Na2SO3对酵母抗氧化能力的影响
Fig. 2Effect of Na2SO3 on YSI-3.7 antioxidant capacity
总抗氧化能力（T-AOC）是衡量机体抗氧化酶系统和非酶促系统功能状况的综合性指标。它的大小可代表和反映机体抗氧化酶系统和非酶系统对外来刺激的代偿能力以及机体自由基代谢的状态。由图2-C所示,在Cr（Ⅲ）胁迫下,酵母的总抗氧化能力有所提升,酵母发挥自身调节作用以对抗外界氧化胁迫作用;500 μg?mL-1 Cr（Ⅲ）处理的酵母体内T-AOC含量为1.61 U?g-1 prot,相比于空白酵母组提高101.25%。1 mmol?L-1 Na2SO3可促进富铬酵母体内T-AOC增加至1.84 U?g-1 prot,分别比空白酵母和500 μg?mL-1 Cr（Ⅲ）处理组中T-AOC含量提高130%和14.29%。表明硫的添加可以提高酵母的总抗氧化能力。
谷胱甘肽过氧化物酶（GSH-Px）可以促进过氧化氢（H2O2）与还原型谷胱甘肽反应生成H2O和氧化型谷胱甘肽（GSSG）。由图2-D可知,500 μg?mL-1 Cr（Ⅲ）处理的酵母体内GSH-Px含量为763.94 U?mg-1 prot,相比于空白酵母组降低26.86%。1 mmol?L-1 Na2SO3可使富铬酵母体内GSH-Px增加至907.53 U?mg-1 prot,比500 μg?mL-1 Cr（Ⅲ）处理组提高18.80%。以上结果表明,硫的添加可以提高谷胱甘肽过氧化物酶的活力,促进氧化氢（H2O2）与还原型谷胱甘肽反应,促进过氧化氢的分解。
3 讨论
动物、植物细胞在代谢过程中不断产生自由基,这些自由基会被细胞本身具有的防御体系所清除,在正常生理条件下,二者之间始终处于动态平衡。一旦平衡被打破,机体组织内的活性氧自由基不断聚积,使组织代谢功能出现异常并发生组织过氧化现象,从而引发一系列病理及生理变化[24]。过量的重金属会诱导活性氧基团（ROS）的产生,如超氧离子（O2-）、羟基(-OH)、过氧化氢（H2O2）等活跃的微粒。这些微粒能与大量细胞成分反应,氧化核酸、蛋白质、糖类和脂肪等大分子,引起细胞内氧化应激反应导致细胞死亡[25]。铬和其他金属一样,会显著诱导活性氧的产生,可以直接或者间接地对生物体中核酸、叶绿体结构和细胞膜造成破坏[26]。PEREIAR等[27]在研究氧化胁迫与酵母抗逆性的关系时也发现,在高温、饥饿、金属离子等逆境因子存在时可诱使酵母细胞产生活性氧ROS。ROS的清除主要包括非酶促和酶促两种机制。其中,非酶促清除机制主要依赖于抗坏血酸、谷胱甘肽、类黄酮和生物碱等还原性物质[28];而酶促清除机制则依赖于超氧化物歧化酶、过氧化氢酶、过氧化物酶、抗坏血酸过氧化物酶和谷胱甘肽过氧化物酶等[29]。KEUNEN等[30]认为,铬（Ⅵ）主要通过硫转运体进入细胞,并且竞争性地抑制硫的摄取,导致硫饥饿,从而引起硫摄取量的减少。在这两者竞争下,硫的补充可以解除铬的毒性,使酵母生长状态变好,蛋白含量增加。GSH等含半胱氨酸残基的巯基化合物,具有抗氧化、提高机体免疫、重金属解毒,维持生物细胞特定的氧化还原氛围等多种生物学功能,是生物细胞内重要的活性物质。硫在蛋白质中的保存增加了GSH的合成。硫通路的激活,不仅可以控制GSH的合成,而且保存蛋白中的硫,为GSH的合成提供S原子。3.1 Na2SO3对酵母膜脂质过氧化程度的影响
六价铬胁迫可能会导致脂质的过氧化以及细胞膜损伤,产生氧化应激损伤[31,32]。在胁迫下,植物组织和器官膜脂质过氧化的主要产物是丙二醛,细胞膜发生过氧化后细胞内电解质大量渗透。植物体内MDA的含量和细胞膜透性可以一定程度上反应植物受胁迫损伤的程度,也能反映细胞膜所受伤害程度的高低[33,34]。Cd2+胁迫可以使美人蕉MDA含量升高[35],SHAH等[36]在Cd2+处理的两种水稻品种中均检测到了MDA的积累。杜君等报道,铜胁迫可以使酿酒酵母膜脂过氧化程度加剧且细胞内丙二醛含量随着铜处理浓度的增加而增加[37]。Al3+作用可以造成烟草细胞的膜脂过氧化[38],对酵母的毒性很大程度上也是膜脂过氧化造成细胞膜完整性和流动性消失引起的[39]。本研究发现,酵母富铬过程中,随着Cr（Ⅲ） 浓度的升高,酵母中MDA含量上升,说明酵母细胞膜质过氧化的程度升高,细胞膜所受伤害程度不断加深。适当浓度的Na2SO3可以使酵母细胞中MDA含量降低,缓解细胞膜脂质过氧化的程度。有报道指出,H2S可以增强抗氧化酶活性,参与调节盐胁迫下植物活性氧代谢,显著降低O2-、H2O2和MDA含量,缓解盐胁迫引起的氧化损伤[40,41,42]。3.2 Na2SO3对酵母生物富铬过程中抗氧化能力的影响
超氧化物歧化酶(SOD)是细胞中最重要的清除自由基的酶之一,以$\mathop{{O}}_{2}^{{\mathop{}_{\ ·}^{-}}}$为基质进行歧化反应,将毒性较强的$\mathop{{O}}_{2}^{{\mathop{}_{\ ·}^{-}}}$转化为毒性次级的H2O2和基态氧,避免毒性更大的·OH的生成。研究表明,Cd2+使美人蕉根部SOD活性明显增加,Cu2+对其活性无明显影响[35]。酿酒酵母细胞内超氧化物歧化酶活性在不同浓度铜胁迫下有不同程度的升高[37]。本研究中添加Na2SO3后酵母中SOD活力比只添加500 μg?mL-1 Cr（Ⅲ）略有上升,说明Na2SO3可以通过提高酵母SOD活力抵抗铬胁迫。本研究还发现,Cr（Ⅲ）可降低酵母体内CAT含量,使酵母体内过氧化氢分解能力减弱,外源添加Na2SO3对CAT酶系没有影响。杜君等[37]发现,酿酒酵母细胞内氧化氢酶的活性在不同浓度铜胁迫下有不同程度的升高。三价铬和铜对酵母过氧化氢酶影响不同,可能与酵母对不同种的金属的抗氧化能力和途径有所不同有关。GSH是含半胱氨酸残基的巯基化合物,具有抗氧化、提高机体免疫、重金属解毒,维持生物细胞特定的氧化还原氛围等多种生物学功能,是生物细胞内重要的活性物质[31]。生物体对重金属的抗逆性、解毒及积累作用与生物细胞内含有丰富的GSH和金属硫蛋白等疏基化合物有关[42,43,44,45]。Fe3+、Cu2+、Cr（Ⅲ）这些变价离子在胁迫细胞时,与酵母细胞中的巯基化合物中巯基发生直接的配位作用[46]。有研究表明,镉处理诱导了水稻根系产生大量的包括还原型谷胱甘肽在内的含巯基物质。谷胱甘肽几乎是所有活细胞中抗氧化剂中最丰富的物质。铬对酵母细胞既然存在氧化胁迫,那么,酵母细胞内必然也存在相应的反应机制来对抗或消除氧化毒性。研究结果说明低浓度的Cr（Ⅲ）可以刺激酵母产生GSH,抵抗氧化毒性。GSH被称为生物体中抵抗重金属压力的缓解剂[47]。GSH在缓解氧化毒性中具有多种功能,如：动物呼吸作用产生的H2O2由线粒体中的谷胱甘肽过氧化物酶（GPx）消除,而GSH就是该酶的电子供体;在植物中,GSH也是活性氧自由基防御反应中的关键因子,并作为一种植物螯合肽底物,可以帮助植物应对金属毒性[48,49,50],如抵抗氧化剂对巯基（-SH）的破坏,与α-生育酚协调清除细胞中积累的氧自由基。GSH还被发现在酿酒酵母的热激、H2O2、Hg、Cu等引起的氧化胁迫中起到关键作用[51,52,53,54]。谷胱甘肽在体内以还原型(GSH)和氧化型(GSSG)两种形式存在,正常时主要以还原型为主,具有清除自由基的能力,可在谷胱甘肽过氧化酶(GPx)的催化下与过氧化物、自由基等反应,形成氧化态的GSSG,GSSG又可在还原型辅酶Ⅱ(NADPH)和GSH还原酶(GSR)的作用下还原成GSH,形成一个循环,这个过程被认为是谷胱甘肽最重要的抗氧化机制。此外,一些报道发现,GSH还具有其他抗性功能。有报道认为,GSH可以保护一些同样含巯基的蛋白质及酶免受氧化,也可以作为一些酶的辅助因子或者具有调节相关氨基酸的运输等功能[55]。还有人发现,GSH可以直接与Cd等金属螯合形成复合物储存到液泡中[13],在植物中,GSH还是植物螯合肽的合成底物[7]。GSH/GSSG是氧化压力的生物标志[56]。随着Cr（Ⅲ）浓度不断升高（0—800 μg?mL-1）,GSH/GSSG分别为4、4.2、3.9和2.8,呈先升高后下降的趋势,说明酵母对低浓度的Cr（Ⅲ）自身抗氧化能力较强,对高浓度的铬抵抗力变弱。
总抗氧化能力（T-AOC）是衡量机体抗氧化酶系统和非酶促系统功能状况的综合性指标。它的大小可代表和反映机体抗氧化酶系统和非酶系统对外来刺激的代偿能力以及机体自由基代谢的状态[57]。在低Cr（Ⅲ）浓度下（≤500 μg?mL-1）,机体自身氧化应激调整,酵母细胞中总抗氧化能力升高;而高浓度Cr（Ⅲ）胁迫下,总抗氧化能力远低于对照组,酵母细胞的抗氧化能力降低,说明高Cr（Ⅲ）对酵母造成了很大的破坏作用,酵母自身氧化应激的调整无法应对此浓度下Cr（Ⅲ）的氧化胁迫。适当浓度的Na2SO3使酵母细胞T-AOC进一步升高,表明Na2SO3可以通过提高酵母总抗氧化能力防御Cr（Ⅲ）带来的氧化作用。
4 结论
酵母在富集Cr（Ⅲ）形成GTF过程中,会受到Cr（Ⅲ）的氧化胁迫作用。较低浓度Cr（Ⅲ）会刺激酵母细胞生长,而较高浓度的Cr（Ⅲ）则会抑制其生长。酵母细胞的膜脂过氧化程度随Cr（Ⅲ）浓度的升高而加重。在较低浓度Cr（Ⅲ）作用下,酵母自身可通过增加T-AOC、GSH、巯基含量以及GSH-Px活力以防御Cr（Ⅲ）的氧化胁迫。但在高Cr（Ⅲ）浓度下,有些未得到及时清除的自由基对细胞产生不可逆的伤害,使细胞膜脂过氧化程度大大加重,酵母自身无法抵抗其氧化胁迫作用。适当浓度Na2SO3可以通过增加酵母中-SH、GSH、T-AOC含量,提高GSH-Px酶活力,降低膜脂过氧化程度,从而帮助酵母细胞抵御一定浓度的Cr（Ⅲ）氧化胁迫作用,进而提高有机铬生成率。参考文献 原文顺序
文献年度倒序
文中引用次数倒序
被引期刊影响因子
DOI:10.3969/j.issn.1673-1085.2012.01.003URL [本文引用: 1]
铬作为动物营养必需的微量元素之一,1959年Schwarz和 Mertz从啤酒酵母中分离出含有铬的葡萄糖耐量因子（Glucose Tolerance Factor,GTF）,证实了GTF具有生物活性的重要结构成分是三价铬离子（Cr3＋）;1974年Mertz证实了GTF是以烟酸-Cr3＋-烟酸 为轴心,含有谷氨酸、甘氨酸和半胱
.
DOI:10.3969/j.issn.1673-1085.2012.01.003URL [本文引用: 1]
铬作为动物营养必需的微量元素之一,1959年Schwarz和 Mertz从啤酒酵母中分离出含有铬的葡萄糖耐量因子（Glucose Tolerance Factor,GTF）,证实了GTF具有生物活性的重要结构成分是三价铬离子（Cr3＋）;1974年Mertz证实了GTF是以烟酸-Cr3＋-烟酸 为轴心,含有谷氨酸、甘氨酸和半胱
DOI:10.2337/diacare.26.4.1277URLPMID:12663610 [本文引用: 1]
OBJECTIVE: To conduct a systematic review of the published literature on the efficacy and safety of herbal therapies and vitamin/mineral supplements for glucose control in patients with diabetes. RESEARCH DESIGN AND METHODS: We conducted an electronic literature search of MEDLINE, OLDMEDLINE, Cochrane Library Database, and HealthSTAR, from database inception to May 2002, in addition to performing hand searches and consulting with experts in the field. Available clinical studies published in the English language that used human participants and examined glycemic control were included. Data were extracted in a standardized manner, and two independent investigators assessed methodological quality of randomized controlled trials using the Jadad scale. RESULTS: A total of 108 trials examining 36 herbs (single or in combination) and 9 vitamin/mineral supplements, involving 4,565 patients with diabetes or impaired glucose tolerance, met the inclusion criteria and were analyzed. There were 58 controlled clinical trials involving individuals with diabetes or impaired glucose tolerance (42 randomized and 16 nonrandomized trials). Most studies involved patients with type 2 diabetes. Heterogeneity and the small number of studies per supplement precluded formal meta-analyses. Of these 58 trials, the direction of the evidence for improved glucose control was positive in 76% (44 of 58). Very few adverse effects were reported. CONCLUSIONS: There is still insufficient evidence to draw definitive conclusions about the efficacy of individual herbs and supplements for diabetes; however, they appear to be generally safe. The available data suggest that several supplements may warrant further study. The best evidence for efficacy from adequately designed randomized controlled trials (RCTs) is available for Coccinia indica and American ginseng. Chromium has been the most widely studied supplement. Other supplements with positive preliminary results include Gymnema sylvestre, Aloe vera, va
DOI:10.1016/j.cbpb.2006.04.012URLPMID:16815060 [本文引用: 1]
Low-molecular-weight chromium-binding substance (LMWCr), also known as chromodulin, is a chromium-binding oligopeptide proposed to have a function in chromium transport and insulin signaling in mammals. In this work, LMWCr has been isolated and purified for the first time from non-mammalian sources: chicken and American alligator. Milligram quantities of the oligopeptide can be obtained from kilogram quantities of liver. The LMWCr's from both sources are asparatate- and glutamate-rich oligopeptides which possess multinuclear chromium assemblies. The composition and physical and spectroscopic properties of the avian and reptilian LMWCr's are extremely similar to those of their mammalian analogues, suggesting the multinuclear sites of the biomolecule from all three classes of animal possess very similar structures. The chicken and alligator oligopeptides may possess intrinsic phosphotyrosine phosphatase activity.
DOI:10.3945/jn.111.139147URLPMID:21593351 [本文引用: 1]
ABSTRACT Chromium was proposed to be an essential element over 50 y ago and was shown to have therapeutic potential in treating the symptoms of type 2 diabetes; however, its mechanism of action at a molecular level is unknown. One chromium-binding biomolecule, low-molecular weight chromium-binding substance (LMWCr or chromodulin), has been found to be biologically active in in vitro assays and proposed as a potential candidate for the in vivo biologically active form of chromium. Characterization of the organic component of LMWCr has proven difficult. Treating bovine LMWCr with trifluoroacetic acid followed by purification on a graphite powder micro-column generates a heptapeptide fragment of LMWCr. The peptide sequence of the fragment was analyzed by MS and tandem MS (MS/MS and MS/MS/MS) using collision-induced dissociation and post-source decay. Two candidate sequences, pEEEEGDD and pEEEGEDD (where pE is pyroglutamate), were identified from the MS/MS experiments; additional tandem MS suggests the sequence is pEEEEGDD. The N-terminal glutamate residues explain the inability to sequence LMWCr by the Edman method. Langmuir isotherms and Hill plots were used to analyze the binding constants of chromic ions to synthetic peptides similar in composition to apoLMWCr. The sequence pEEEEGDD was found to bind 4 chromic ions per peptide with nearly identical cooperativity and binding constants to those of apoLMWCr. This work should lead to further studies elucidating or eliminating a potential role for LMWCr in treating the symptoms of type 2 diabetes and other conditions resulting from improper carbohydrate and lipid metabolism.
DOI:10.1016/j.fct.2004.02.015PMID:15110112 [本文引用: 1]
Trivalent chromium is an essential element required for normal carbohydrate, lipid, and protein metabolism in humans and animals. This article describes how one particular form of trivalent chromium, chromium tripicolinate (Chromax03), a stable complex of trivalent chromium and picolinic acid, was determined to be safe for use as a nutrient supplement in foods (i.e., nutritional bars and beverages). A safety assessment of a nutrient supplement for use in food requires an evaluation of the safety of the product (Chromax03), as well as an evaluation of the safety of the intended dietary ingredient (chromium tripicolinate). In this assessment, the production process, final product specifications, and product analysis results for Chromax03 were evaluated to determine the safety of the final product. Then, the Estimated Daily Intakes (EDIs) of trivalent chromium and picolinic acid from the proposed use of Chromax03 were calculated using data from the USDA's most recent Continuing Survey of Food Intakes by Individuals. The EDI for trivalent chromium was compared to the Acceptable Daily Intake (ADI) for this compound derived from animal studies, corroborated with human data, while the EDI for picolinic acid was compared to existing in vivo exposure to this compound that occurs naturally in the body. As long as the EDI of trivalent chromium is less than the ADI for this compound and the EDI of picolinic acid is less than its estimated in vivo exposure, Chromax03 can be considered safe for its intended use. Employing this approach, it was determined that Chromax03 is safe, as well as generally recognized as safe (GRAS), for use in nutritional bars and beverages as a nutrient supplement at a maximum use level of 2.4 mg of Chromax03 per product serving.
DOI:10.1016/j.freeradbiomed.2007.04.007URLPMID:17561102 [本文引用: 1]
Repair of DNA damage is fundamental for cellular tolerance to ionizing radiation (IR) and many IR-induced DNA lesions are thought to occur as a result of oxidative stress. We investigated the physiological effects of IR in Saccharomyces cerevisiae by performing protein expression profiles in cells exposed to electron pulse irradiation. Transient induction of several antioxidant enzymes in wild-type cells, but not in cells lacking the oxidative stress regulator Yap1, indicated that IR exposure causes cellular oxidative stress. Yap1 activation involved oxidation to the intramolecular disulfide bond, a signature of activation by peroxide, and was dependent on the Yap1 peroxide sensor Orp1/Gpx3. H 2O 2 was produced in the culture medium of irradiated cells and was both necessary and sufficient for IR-induced Yap1 activation. When IR was performed in the presence of N 2O, obviating H 2O 2 production and increasing hydroxyl radical ( OH) production, the Yap1 response was lost, indicating that Yap1 was unable to respond to OH or OH-induced damage. However, the Yap1 response to IR did not seem to be a primary determinant of cellular IR tolerance. Altogether, these data provide a molecular demonstration that cells experience in vivo peroxide stress during IR and indicate that the H 2O 2 produced cannot account for IR toxicity.
DOI:10.1016/j.foodchem.2007.10.065URL [本文引用: 2]
Oxidative browning is a long-standing problem in winemaking and sulphur dioxide is the generally used antioxidant to control wine browning. However, concerns over its ability to induce severe allergic reactions have created a great need for its reduction or replacement in recent years. Furthermore, ascorbic acid seems unsuccessful as an alternative antioxidant in winemaking. So a comprehensive understanding of the chemistry of wine browning is essential to study new antioxidant(s) for the protection of wine from browning. The review systematically outlines the mechanisms of wine browning including enzymic and non-enzymic browning happening in winemaking and discusses the central roles performed by iron and copper in the chemistry of wine oxidation. Iron and copper might play a central role in initiating wine non-enzymic browning, and this has important implications in studying antioxidant substitute for sulphur dioxide in wine.
DOI:10.1111/j.1755-0238.2006.tb00043.xURL [本文引用: 1]
The effect of high sugar concentrations or the presence of copper residues on fermentation efficiency and volatile acid (VA) production were examined for selected commercial wine yeast strains. Fermentation rate as measured by accumulated mass loss appeared to be least affected by high sugar concentrations during the first few days of fermentation for strains VIN13, WE14, N96 and RJ11. It was, however, only fermentations using VIN13, WE372, N96 and L2056 that contained less than 11 g/L fructose after 21 days. VIN13 and RJ11 produced the lowest VA in the 21 o , 25 o and 28 o Brix musts. Fermentation efficiency of six strains was also studied in must containing 0.25 mM Cu 2+ . Results indicated that strains NT50, Collection C茅page Cabernet (CC) and D80 were not significantly affected, whereas VIN13, NT112 and RJ11 contained significantly more glucose and fructose after fermentation in the must containing copper. Copper addition also increased VA production, with strains RJ11 and NT50 being the most affected.
URL [本文引用: 1]
以荔枝汁为发酵培养基,用硫酸铜分别调节荔枝汁的铜离子浓度为0.05、0.25 mmol/L,研究不同铜离子浓度对荔枝酒降酸酿酒酵母发酵进程及醋酸代谢的影响。结果表明,铜胁迫荔枝降酸酿酒酵母严重抑制了荔枝汁发酵过程中酵母的生长,铜离子浓度越高,迟滞期越长,酵母数量越少。0.05、0.25 mmol/L的铜胁迫并不明显影响酵母的存活率。0.25 mmol/L的铜很大程度上抑制了荔枝降酸酿酒酵母的发酵进程,表现为酒精度低、残糖高,与对照相比差异显著。0.05mmol/L以上的铜胁迫,降低了酵母的醋酸代谢能力及ACS酶活性。
.
URL [本文引用: 1]
以荔枝汁为发酵培养基,用硫酸铜分别调节荔枝汁的铜离子浓度为0.05、0.25 mmol/L,研究不同铜离子浓度对荔枝酒降酸酿酒酵母发酵进程及醋酸代谢的影响。结果表明,铜胁迫荔枝降酸酿酒酵母严重抑制了荔枝汁发酵过程中酵母的生长,铜离子浓度越高,迟滞期越长,酵母数量越少。0.05、0.25 mmol/L的铜胁迫并不明显影响酵母的存活率。0.25 mmol/L的铜很大程度上抑制了荔枝降酸酿酒酵母的发酵进程,表现为酒精度低、残糖高,与对照相比差异显著。0.05mmol/L以上的铜胁迫,降低了酵母的醋酸代谢能力及ACS酶活性。
DOI:10.1007/s10535-008-0111-7URL [本文引用: 1]
AbstractLemna minor L. treated with 20, 50, or 100 M CuSO4 accumulated Cu and reactive oxygen species (hydrogen peroxide and superoxide radical) in frond and root cells. The time-course analysis of lipid peroxidation showed high increment in malondialdehyde production only after 12 and 48 h of Cu treatment. Guaiacol peroxidase and superoxide dismutase activities decreased after 48 h while glutathione reductase activity enhanced 48 h after Cu-treatment. Ascorbate and glutathione contents increased with the increasing Cu stress.
DOI:10.1016/S0300-483X(03)00159-8URLPMID:12821289 [本文引用: 1]
Copper (Cu) is an integral part of many important enzymes involved in a number of vital biological processes. Although normally bound to proteins, Cu may be released and become free to catalyze the formation of highly reactive hydroxyl radicals. Data obtained from in vitro and cell culture studies are largely supportive of Cu's capacity to initiate oxidative damage and interfere with important cellular events. Oxidative damage has been linked to chronic Cu-overload and/or exposure to excess Cu caused by accidents, occupational hazards, and environmental contamination. Additionally, Cu-induced oxidative damage has been implicated in disorders associated with abnormal Cu metabolism and neurodegenerative changes. Interestingly, a deficiency in dietary Cu also increases cellular susceptibility to oxidative damage. A number of nutrients have been shown to interact with Cu and alter its cellular effects. Vitamin E is generally protective against Cu-induced oxidative damage. While most in vitro or cell culture studies show that ascorbic acid aggravates Cu-induced oxidative damage, results obtained from available animal studies suggest that the compound is protective. High intakes of ascorbic acid and zinc may provide protection against Cu toxicity by preventing excess Cu uptake. Zinc also removes Cu from its binding site, where it may cause free radical formation. Beta-carotene, alpha-lipoic acid and polyphenols have also been shown to attenuate Cu-induced oxidative damage. Further studies are needed to better understand the cellular effects of this essential, but potentially toxic, trace mineral and its functional interaction with other nutrients.
DOI:10.1023/A:1006345126589URL [本文引用: 1]
DOI:10.1016/0027-5107(96)00051-6URLPMID:8841482 [本文引用: 2]
Abstract The heavy metal cadmium is a carcinogen in long-term rodent studies and is a suspect human carcinogen. Cadmium scores negative in the Ames Salmonella mutagenicity assay and in most other short-term genotoxicity assays, but induces deletions in the yeast Saccharomyces cerevisiae. We have investigated whether cadmium induces an oxidative stress in S. cerevisiae which may be responsible for its recombinagenic activity. The free radical scavenger N-acetylcysteine blocked toxicity and recombination induced in S. cerevisiae by cadmium. Yeast strains deficient in the antioxidant defense enzymes superoxide dismutase or gamma-glutamylcysteine synthetase were hypersensitive to cadmium toxicity. Cells grown in the absence of oxygen were more resistant to cadmium. An intracellular free radical-sensitive reporter compound was activated in S. cerevisiae exposed to cadmium. Toxicity or recombination induced by the mutagenic carcinogen methyl methanesulfonate were unaffected in any of the above experiments. These results suggest that the toxicity and recombinagenic activity of cadmium in S. cerevisiae is caused by oxidative stress.
[本文引用: 1]
DOI:10.1007/s00204-008-0313-yURL [本文引用: 1]
[本文引用: 1]
DOI:10.1007/s00204-008-0313-yURL [本文引用: 1]
URL [本文引用: 1]
以从本试验室收藏的7株酵母菌种及其7株经空间搭载(实践八号)诱变后的酵母菌株为研究对象,通过梯度含铬YEPD平板培养和液体YPD培养基发酵试验,利用氨水提取菌体中的GTF和火焰原子吸收光谱法检测其有机铬含量,从中筛选出一株葡萄糖耐量因子的高产酵母(YS-3),有机铬含量达1296μg/g,总铬含量达1926μg/g,生物量为40g/L。同时分析了菌体发酵过程中,菌体有机铬富集量与其它发酵参数的动态关系。
URL [本文引用: 1]
以从本试验室收藏的7株酵母菌种及其7株经空间搭载(实践八号)诱变后的酵母菌株为研究对象,通过梯度含铬YEPD平板培养和液体YPD培养基发酵试验,利用氨水提取菌体中的GTF和火焰原子吸收光谱法检测其有机铬含量,从中筛选出一株葡萄糖耐量因子的高产酵母(YS-3),有机铬含量达1296μg/g,总铬含量达1926μg/g,生物量为40g/L。同时分析了菌体发酵过程中,菌体有机铬富集量与其它发酵参数的动态关系。
DOI:10.1039/AN9952000931URLPMID:7741257 [本文引用: 1]
Abstract The transport of [51Cr]chromate into human erythrocytes and isolated rat hepatocytes has been investigated. It was found that uptake in both cell types could be inhibited by the established anion carrier inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid. The uptake was very fast, and in kinetic studies a very low Km was found for both cell types, indicating either a high affinity of chromate for the carrier, and/or, more probably, an efficient intracellular reduction and trapping of 51Cr. The transport capacity, however, was of the same magnitude as for physiological substrates, such as lactate and sulfate. The uptake was temperature dependent and the activation energy was of the same magnitude as that for the physiological substrates. The uptake could be partly inhibited by high levels (mmol l-1) of lactate, pyruvate or sulfate. The uptake rate was greatly increased at lower pH (6.0 versus 7.4) which could indicate transport of the HCrO4- form or an increased intracellular rate of CrVI reduction. The results showed efficient uptake of 51CrO4(2-) by erythrocytes and hepatocytes. They were consistent with a mechanism of uptake which involved the cell membrane anion-exchange carrier in the transport and trapping of 51Cr within the cell.
DOI:10.1016/j.mib.2009.02.003URLPMID:19282236 [本文引用: 1]
Some elements are essential for life and others closely related to them are very toxic. In exploiting unique ecological niches many prokaryotes have evolved the means to defend themselves against and even to derive energy from deleterious elements. Toxic metal defense systems are related to those providing homeostasis of essential metals and metalloid elements. Expression of these multiprotein systems is costly but they must respond rapidly and, so, all are well controlled. Seven diverse families of metalloregulators are presently recognized for essential metal homeostasis in prokaryotes. Two of these, the ArsR and MerR families, figure more often than the others in controlling responses to toxic transition metals and metalloids. This review emphasizes recent advances in these two metalloregulator families and highlights emerging regulatory motifs of other types.
DOI:10.1021/tx700198aURLPMID:17970581 [本文引用: 1]
Abstract Chronic exposure to nickel(II), chromium(VI), or inorganic arsenic (iAs) has long been known to increase cancer incidence among affected individuals. Recent epidemiological studies have found that carcinogenic risks associated with chromate and iAs exposures were substantially higher than previously thought, which led to major revisions of the federal standards regulating ambient and drinking water levels. Genotoxic effects of Cr(VI) and iAs are strongly influenced by their intracellular metabolism, which creates several reactive intermediates and byproducts. Toxic metals are capable of potent and surprisingly selective activation of stress-signaling pathways, which are known to contribute to the development of human cancers. Depending on the metal, ascorbate (vitamin C) has been found to act either as a strong enhancer or suppressor of toxic responses in human cells. In addition to genetic damage via both oxidative and nonoxidative (DNA adducts) mechanisms, metals can also cause significant changes in DNA methylation and histone modifications, leading to epigenetic silencing or reactivation of gene expression. In vitro genotoxicity experiments and recent animal carcinogenicity studies provided strong support for the idea that metals can act as cocarcinogens in combination with nonmetal carcinogens. Cocarcinogenic and comutagenic effects of metals are likely to stem from their ability to interfere with DNA repair processes. Overall, metal carcinogenesis appears to require the formation of specific metal complexes, chromosomal damage, and activation of signal transduction pathways promoting survival and expansion of genetically/epigenetically altered cells.
DOI:10.1002/app.12197URLPMID:18794233 [本文引用: 1]
Chromate is a widespread pollutant as a waste of human activities. However, the mechanisms underlying its high toxicity are not clearly understood. In this work, we used the yeast Saccharomyces cerevisiae to analyse the physiological effects of chromate exposure in a eukaryote cell model. We show that chromate causes a strong decrease of sulfate assimilation and sulfur metabolite pools suggesting that cells experience sulfur starvation. As a consequence, nearly all enzymes of the sulfur pathway are highly induced as well as enzymes of the sulfur-sparing response such as Pdc6, the sulfur-poor pyruvate decarboxylase. The induction of Pdc6 was regulated at the mRNA level and dependent upon Met32, a coactivator of Met4, the transcriptional activator of the sulfur pathway. Finally, we found that chromate enters the cells mainly through sulfate transporters and competitively inhibits sulfate uptake. Also consistent with a competition between the two substrates, sulfate supplementation relieves chromate toxicity. However, the data suggest that the chromate-mediated sulfur depletion is not simply due to this competitive uptake but would also be the consequence of competitive metabolism between the two compounds presumably at another step of the sulfur assimilation pathway.
DOI:10.11686/cyxb20100512URLMagsci [本文引用: 1]
<FONT face=Verdana>将２种中性盐ＮａＣｌ、Ｎａ<SUB>２</SUB>ＳＯ<SUB>４</SUB> 及２种碱性盐Ｎａ<SUB>２</SUB>ＣＯ<SUB>３</SUB>、ＮａＨＣＯ<SUB>３</SUB> 按不同比例混合，模拟出２４种盐度和碱度各不相同的复杂盐碱条件，处理黄顶菊种子，测定其发芽率、发芽指数以及黄顶菊幼苗的茎高和根长，旨在明确盐碱胁迫对黄顶菊种子萌发和幼苗生长的影响；同时测定了盐碱胁迫下黄顶菊叶片叶绿素、丙二醛（ｍａｌｏｎｄｉａｌｄｅｈｙｄｅ，ＭＤＡ）含量及超氧化物歧化酶（ｓｕｐｅｒｏｘｉｄｅｄｉｓｍｕｔａｓｅ，ＳＯＤ）、过氧化物酶（ｐｅｒｏｘｉｄａｓｅ，ＰＯＤ）和过氧化氢酶（ｃａｔａｌａｓｅ，ＣＡＴ）活性，初步探讨了黄顶菊耐盐碱胁迫的机理。结果表明，盐浓度与Ａ、Ｂ、Ｃ、Ｄ４组的发芽率、发芽指数、根长以及茎高均表现为负效应，在相同盐浓度的处理下，随着盐溶液碱性的降低各处理的发芽率、发芽指数、根长以及茎高均明显上升；对各胁迫因素与发芽率、发芽指数、根长以及茎高之间进行统计学分析表明，在各胁迫因素中盐浓度是影响黄顶菊种子萌发和幼苗生长的主导因素，ｐＨ 值对黄顶菊种子萌发和幼苗生长没有决定性作用。盐碱胁迫处理后黄顶菊叶片叶绿素相对破坏率上升，细胞膜透性加大，叶片中丙二醛含量升高，盐碱胁迫初期黄顶菊叶片中ＳＯＤ 和ＰＯＤ 的活性升高，ＣＡＴ 活性与对照相比差异不显著，表明盐碱胁迫初期黄顶菊叶片中主要靠ＳＯＤ 和ＰＯＤ 的活性来暂时维持活性氧产生与清除的动态平衡。</FONT>
DOI:10.11686/cyxb20100512URLMagsci [本文引用: 1]
<FONT face=Verdana>将２种中性盐ＮａＣｌ、Ｎａ<SUB>２</SUB>ＳＯ<SUB>４</SUB> 及２种碱性盐Ｎａ<SUB>２</SUB>ＣＯ<SUB>３</SUB>、ＮａＨＣＯ<SUB>３</SUB> 按不同比例混合，模拟出２４种盐度和碱度各不相同的复杂盐碱条件，处理黄顶菊种子，测定其发芽率、发芽指数以及黄顶菊幼苗的茎高和根长，旨在明确盐碱胁迫对黄顶菊种子萌发和幼苗生长的影响；同时测定了盐碱胁迫下黄顶菊叶片叶绿素、丙二醛（ｍａｌｏｎｄｉａｌｄｅｈｙｄｅ，ＭＤＡ）含量及超氧化物歧化酶（ｓｕｐｅｒｏｘｉｄｅｄｉｓｍｕｔａｓｅ，ＳＯＤ）、过氧化物酶（ｐｅｒｏｘｉｄａｓｅ，ＰＯＤ）和过氧化氢酶（ｃａｔａｌａｓｅ，ＣＡＴ）活性，初步探讨了黄顶菊耐盐碱胁迫的机理。结果表明，盐浓度与Ａ、Ｂ、Ｃ、Ｄ４组的发芽率、发芽指数、根长以及茎高均表现为负效应，在相同盐浓度的处理下，随着盐溶液碱性的降低各处理的发芽率、发芽指数、根长以及茎高均明显上升；对各胁迫因素与发芽率、发芽指数、根长以及茎高之间进行统计学分析表明，在各胁迫因素中盐浓度是影响黄顶菊种子萌发和幼苗生长的主导因素，ｐＨ 值对黄顶菊种子萌发和幼苗生长没有决定性作用。盐碱胁迫处理后黄顶菊叶片叶绿素相对破坏率上升，细胞膜透性加大，叶片中丙二醛含量升高，盐碱胁迫初期黄顶菊叶片中ＳＯＤ 和ＰＯＤ 的活性升高，ＣＡＴ 活性与对照相比差异不显著，表明盐碱胁迫初期黄顶菊叶片中主要靠ＳＯＤ 和ＰＯＤ 的活性来暂时维持活性氧产生与清除的动态平衡。</FONT>
DOI:10.3321/j.issn:1672-2043.2008.03.055URL [本文引用: 1]
为了研究不同浓度的水体铜对黄河鲤肝胰脏抗氧化能力的影响,采用0.01、0.05、0.10、0.30、0.50、0.70和1.00 mg·L-1 Cu2+分别刺激黄河鲤1、3、5、7 d后,测定黄河鲤肝胰脏抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT和谷胱甘肽过氧化物酶GPx)的活性及总抗氧化能力(T-AOC).结果表明,黄河鲤暴露于0.01mg·L-1Cu2+溶液时,SOD、CAT和GPx活性及T-AOC高于对照组,其中GPx活性达到最大,且显著高于对照组(P<0.05),T-AOC 3、5、7 d时,显著高于对照组(P<0.05);Cu2+度为0.05 mg·L-1时,SOD和CAT活性及T-AOC(P<0.05)达到最大,其中SOD和CAT活性3、5、7 d时,显著高于对照组(P<0.05),GPx活性1 d时高于对照组,3、5、7 d时低于对照组,其中5、7 d时,显著低于对照组(P<0.05);Cu2+浓度为0.10 mg·L-1时,SOD活性3、5、7 d显著低于对照组(P<0.05),CAT和GPx活性及T-AOC显著低于对照组(P<0.05);高浓度组(0.30、0.50、0.70和1.00 mg·L-1)Cu2+抑制了SOD、CAT和GPx活性及T-AOC.结果提示,黄河鲤肝胰脏SOD、CAT和GPx活性及T-AOC对铜的污染均具指示作用,其中最为灵敏的是GPx活性.可以用来指示低剂量重金属的污染.
DOI:10.3321/j.issn:1672-2043.2008.03.055URL [本文引用: 1]
为了研究不同浓度的水体铜对黄河鲤肝胰脏抗氧化能力的影响,采用0.01、0.05、0.10、0.30、0.50、0.70和1.00 mg·L-1 Cu2+分别刺激黄河鲤1、3、5、7 d后,测定黄河鲤肝胰脏抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT和谷胱甘肽过氧化物酶GPx)的活性及总抗氧化能力(T-AOC).结果表明,黄河鲤暴露于0.01mg·L-1Cu2+溶液时,SOD、CAT和GPx活性及T-AOC高于对照组,其中GPx活性达到最大,且显著高于对照组(P<0.05),T-AOC 3、5、7 d时,显著高于对照组(P<0.05);Cu2+度为0.05 mg·L-1时,SOD和CAT活性及T-AOC(P<0.05)达到最大,其中SOD和CAT活性3、5、7 d时,显著高于对照组(P<0.05),GPx活性1 d时高于对照组,3、5、7 d时低于对照组,其中5、7 d时,显著低于对照组(P<0.05);Cu2+浓度为0.10 mg·L-1时,SOD活性3、5、7 d显著低于对照组(P<0.05),CAT和GPx活性及T-AOC显著低于对照组(P<0.05);高浓度组(0.30、0.50、0.70和1.00 mg·L-1)Cu2+抑制了SOD、CAT和GPx活性及T-AOC.结果提示,黄河鲤肝胰脏SOD、CAT和GPx活性及T-AOC对铜的污染均具指示作用,其中最为灵敏的是GPx活性.可以用来指示低剂量重金属的污染.
DOI:10.1016/S1937-6448(08)01403-2URLPMID:19081535 [本文引用: 1]
Abstract Programmed cell death (PCD), the highly regulated dismantling of cells, is essential for plant growth and survival. PCD plays key roles in embryo development, formation and maturation of many cell types and tissues, and plant reaction/adaptation to environmental conditions. Reactive oxygen species (ROS) are not only toxic by products of aerobic metabolism with strictly controlled cellular levels, but they also function as signaling agents regulating many biological processes and producing pleiotropic effects. Over the last decade, ROS have become recognized as important modulators of plant PCD. Molecular genetic approaches using plant mutants and transcriptome studies related to ROS-mediated PCD have revealed a wide array of plant-specific cell death regulators and have contributed to unraveling the elaborate redox signaling network. This review summarizes the biological processes, in which plant PCD participates and discusses the signaling functions of ROS with emphasis on hydrogen peroxide.
URLPMID:20120464 [本文引用: 1]
Due to widespread industrial use, chromium (Cr) is considered a hazardous environmental pollutant. It is known to inhibit plantgrowth and development. The present study provides the evidence of the phytotoxicity of this metal on the pea (Pisum sativum L. cv Azad)plants. The plants of pea (Pisum sativum L.) were grown in refined sand under different concentrations i.e. 0.05, 0.1, 0.2, 0.3 and 0.4 mMof Cr (VI) in order to study the effect on growth and yield, photosynthetic pigments, relative water content, non-reducing sugar and proteinwith activity of certain enzymes like catalase, peroxidase, starch phosphorylase and ribonuclease. The analysis of the results showed thatphotosynthetic pigments (68.68%), relative water contents (62.77%), non-reducing sugar (66.66%) and protein (81.57%) were decreasealong with reduction in plant height (52.69% ) and leaf area (50.81%) of the pea plants. However, in response to various concentration ofCr exposed plants showed significant induction of reducing and total sugars with enzymes like catalase, starch phosphorylase andribonuclease. The translocation of Cr in various part of pea plant have been found in order of root> stem> leaves>seeds which rangedbetween 34.8 to 217.3 mg g-1 d.wt. (dry weight) in roots, 6.5 to 173.13 mg g-1 d.wt. in shoot, 4.2 to 74.43 mg g-1 d.wt. in leaves and 0.94to 8.64 mg g-1 d.wt. in seeds, that is also reflected by the transfer factor of Cr from refined sand to tested species.
.
DOI:10.1016/S0304-4165(03)00003-5URLPMID:12595095 [本文引用: 1]
Eukaryotic cells have developed mechanisms to rapidly respond towards the environment by changing the expression of a series of genes. There is increasing evidence that reactive oxygen species (ROS), besides causing damage, may also fulfill an important role as second messengers involved in signal transduction. Recently, we have demonstrated that deletion of SOD1 is beneficial for the acquisition of tolerance towards heat and ethanol stresses. The present report demonstrates that a sod1 mutant was the only one capable of acquiring tolerance against a subsequent stress produced by menadione, although this mutant strain had exhibited high sensitivity to oxidative stress. By measuring the level of intracellular oxidation, lipid peroxidation as well as glutathione metabolism, we have shown that in the SOD1-deleted strain, an unbalance occurs in the cell redox status. These results indicated that the capacity of acquiring tolerance to oxidative stress is related to a signal given by one or all of the above factors.
DOI:10.1146/annurev.arplant.55.031903.141701URL [本文引用: 1]
DOI:10.1016/j.tplants.2004.08.009URLPMID:15465684 [本文引用: 1]
Reactive oxygen species (ROS) control many different processes in plants. However, being toxic molecules, they are also capable of injuring cells. How this conflict is resolved in plants is largely unknown. Nonetheless, it is clear that the steady-state level of ROS in cells needs to be tightly regulated. In Arabidopsis, a network of at least 152 genes is involved in managing the level of ROS. This network is highly dynamic and redundant, and encodes ROS-scavenging and ROS-producing proteins. Although recent studies have unraveled some of the key players in the network, many questions related to its mode of regulation, its protective roles and its modulation of signaling networks that control growth, development and stress response remain unanswered.
DOI:10.3390/ijms12106894URLPMID:3211017 [本文引用: 1]
A general status of oxidative stress in plants caused by exposure to elevated metal concentrations in the environment coincides with a constraint on mitochondrial electron transport, which enhances ROS accumulation at the mitochondrial level. As mitochondria are suggested to be involved in redox signaling under environmental stress conditions, mitochondrial ROS can initiate a signaling cascade mediating the overall stress response,i.e., damageversusadaptation. This review highlights our current understanding of metal-induced responses in plants, with focus on the production and detoxification of mitochondrial ROS. In addition, the potential involvement of retrograde signaling in these processes will be discussed.
DOI:10.1007/s10534-011-9459-9URLPMID:21562773 [本文引用: 2]
Abstract of CrCl·6HO. Samples of plant tissues were digested with HNO/HCl in a closed-vessel microwave system and the concentrations of Cr determined using inductively-coupled plasma mass spectrometry (ICP-MS). The ultrastructure of root, stem and leaf tissue was examined using transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) in order to determine the sites of accumulation of Cr and to detect possible alterations in cell organelles induced by the presence of the metal. Chromium accumulated principally in the roots of the four macrophytes (8.6–3002mg02kg dw), with much lower concentrations present in the stems and leaves (3.8–8.6 and 0.01–9.002mg02kg dw, respectively). Within root tissue, Cr was present mainly in the vacuoles of parenchyma cells and cell walls of xylem and parenchyma. Alterations in the shape of the chloroplasts and nuclei were detected in A. philoxeroides and B. scabiosoides, suggesting a possible application of these aquatic plants as biomarkers from Cr contamination.
DOI:10.1155/2014/975946PMID:4053220 [本文引用: 1]
Chromium (Cr) is present in our environment as a toxic pollutant, which needs to be removed using phytoremediation technology. In present study, two transgenic cotton cultivars (J208, Z905) and their hybrid line (ZD14) were used to explore their Cr uptake and tolerance potential using multiple biomarkers approach. Four different levels of Cr (CK, 10, 50, and 10065μM) were applied. Cr caused a significant reduction in root/shoot length, number of secondary roots, and root fresh and dry biomasses at 100 μM. Cr accumulated more in roots and was found higher in hybrid line (ZD14) as compared with its parent lines (J208, Z905) at all Cr stress levels (10, 50, and 10065μM). Cr translocation was less than 1 in all cultivars. Ultrastructural studies at 10065μM Cr showed an increase in number of nuclei and vacuoles and presence of Cr dense granules in dead parts of the cell (vacuoles/cell wall). Malondialdehyde (MDA), hydrogen peroxide (H2O2), total soluble proteins, superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR) as a whole were upregulated with elevated levels of Cr. Higher Cr uptake by roots, accelerated metabolism, and Cr sequestration in dead parts of the cell indicate that these cotton cultivars can be useful for Cr accumulation and tolerance.
DOI:10.3969/j.issn.1001-3865.2012.10.009URL [本文引用: 1]
以沉水植物苦草、轮叶黑藻、狐尾藻为研究对象,分别研究了在不同盐度下3种沉水植物的生物学指标和生理状况,以期为沿海地区水系沉水植物构建提供依据。结果表明,在0.05mol/L盐度下轮叶黑藻、苦草出现生长抑制,株高、鲜质量下降,叶片中丙二醛含量增加,单株叶片面积减小,而狐尾藻在0.05mol/L盐度下生长良好,0.08mol/L盐度下出现株高、鲜质量下降,叶片中丙二醛含量增高的现象。因此,推荐盐度在0.05mol/L以下的水体,可以建植苦草和轮叶黑藻,盐度不高于0.08mol/L的水体可以建植狐尾藻。盐胁迫下沉水植物会表现为一定的抗逆性,会通过单株叶片面积减小、增加根冠比、叶片肉质化等措施来减少水分流失和保证机体的正常生理功能,但超过一定的阀值,抗逆性会减弱,导致沉水植物出现生长抑制或者死亡现象。在有一定盐度的水体进行沉水植物建植恢复,该沉水植物能够耐受的盐度高于水体的盐度,是保证沉水植物成活的基本前提。
DOI:10.3969/j.issn.1001-3865.2012.10.009URL [本文引用: 1]
以沉水植物苦草、轮叶黑藻、狐尾藻为研究对象,分别研究了在不同盐度下3种沉水植物的生物学指标和生理状况,以期为沿海地区水系沉水植物构建提供依据。结果表明,在0.05mol/L盐度下轮叶黑藻、苦草出现生长抑制,株高、鲜质量下降,叶片中丙二醛含量增加,单株叶片面积减小,而狐尾藻在0.05mol/L盐度下生长良好,0.08mol/L盐度下出现株高、鲜质量下降,叶片中丙二醛含量增高的现象。因此,推荐盐度在0.05mol/L以下的水体,可以建植苦草和轮叶黑藻,盐度不高于0.08mol/L的水体可以建植狐尾藻。盐胁迫下沉水植物会表现为一定的抗逆性,会通过单株叶片面积减小、增加根冠比、叶片肉质化等措施来减少水分流失和保证机体的正常生理功能,但超过一定的阀值,抗逆性会减弱,导致沉水植物出现生长抑制或者死亡现象。在有一定盐度的水体进行沉水植物建植恢复,该沉水植物能够耐受的盐度高于水体的盐度,是保证沉水植物成活的基本前提。
DOI:10.15889/j.issn.1002-1302.2015.04.090URL [本文引用: 1]
以金花3号金银花为材料,分别采用不同浓度Na Cl盐溶液处理,分析金花3号金银花在不同盐浓度胁迫下丙二醛(MDA)、脯氨酸(Pro)、可溶性糖、超氧化物歧化酶(SOD)、过氧化物酶(POD)5个生理指标含量的变化,探讨其耐盐性。结果表明,随土壤盐分的积累及胁迫时间的延续,金花3号金银花不同程度地表现出盐害现象,对盐的最大忍受度为土壤含盐量为12.48 g/kg;在盐胁迫8 d后,在部分处理下SOD和POD含量出现不同程度的升高,丙二醛含量出现下降;Pro在盐胁迫前4 d迅速升高后下降,在部分处理下可溶性糖含量先降后升。
DOI:10.15889/j.issn.1002-1302.2015.04.090URL [本文引用: 1]
以金花3号金银花为材料,分别采用不同浓度Na Cl盐溶液处理,分析金花3号金银花在不同盐浓度胁迫下丙二醛(MDA)、脯氨酸(Pro)、可溶性糖、超氧化物歧化酶(SOD)、过氧化物酶(POD)5个生理指标含量的变化,探讨其耐盐性。结果表明,随土壤盐分的积累及胁迫时间的延续,金花3号金银花不同程度地表现出盐害现象,对盐的最大忍受度为土壤含盐量为12.48 g/kg;在盐胁迫8 d后,在部分处理下SOD和POD含量出现不同程度的升高,丙二醛含量出现下降;Pro在盐胁迫前4 d迅速升高后下降,在部分处理下可溶性糖含量先降后升。
DOI:10.3321/j.issn:1672-2043.2007.04.033URL [本文引用: 2]
通过测定植物的丙二醛（MDA）含量、酸溶性SH含量以及两种抗氧化酶（超氧化物歧化酶SOD和愈创木酚过氧化物酶GPX）的酶活,研究了重金属镉（Cd）和铜（Cu）对美人蕉（Canna indica Linn.）的氧化胁迫.结果表明,20 μmol·L^-1和100 μmol·L^-1的Cd^2＋Cu^2＋均使其根部MDA含量显著增加,但除了100 μmol·L^-1的Cd^2＋,叶部MDA含量无明显变化.与Cu^2＋相比,Cd^2＋能引起植物根部GSH的明显提高,并能诱导PCs的产生.Cd^2＋使根部SOD活性明显增加,Cu^2＋对其活性无明显影响.两种重金属均使其根部GPX活性显著增加.对于叶,重金属胁迫能增加GPX的活性,但对SOD活性的影响不明显.以上结果表明,重金属镉和铜对美人蕉具有氧化胁迫作用,而美人蕉具有缓解重金属胁迫的解毒机制,诱导PCs解毒,同时它能通过调节抗氧化物酶的活性增强其抗氧化胁迫的能力,这为该植物作为中低浓度镉和铜污染水体的修复植物种类应用提供了可能.
DOI:10.3321/j.issn:1672-2043.2007.04.033URL [本文引用: 2]
通过测定植物的丙二醛（MDA）含量、酸溶性SH含量以及两种抗氧化酶（超氧化物歧化酶SOD和愈创木酚过氧化物酶GPX）的酶活,研究了重金属镉（Cd）和铜（Cu）对美人蕉（Canna indica Linn.）的氧化胁迫.结果表明,20 μmol·L^-1和100 μmol·L^-1的Cd^2＋Cu^2＋均使其根部MDA含量显著增加,但除了100 μmol·L^-1的Cd^2＋,叶部MDA含量无明显变化.与Cu^2＋相比,Cd^2＋能引起植物根部GSH的明显提高,并能诱导PCs的产生.Cd^2＋使根部SOD活性明显增加,Cu^2＋对其活性无明显影响.两种重金属均使其根部GPX活性显著增加.对于叶,重金属胁迫能增加GPX的活性,但对SOD活性的影响不明显.以上结果表明,重金属镉和铜对美人蕉具有氧化胁迫作用,而美人蕉具有缓解重金属胁迫的解毒机制,诱导PCs解毒,同时它能通过调节抗氧化物酶的活性增强其抗氧化胁迫的能力,这为该植物作为中低浓度镉和铜污染水体的修复植物种类应用提供了可能.
DOI:10.1016/S0168-9452(01)00517-9URL [本文引用: 1]
When seedlings of two rice cvs Ratna and Jaya were grown in sand cultures for a period of 5–20 days in the presence of 100 and 500 μM Cd(NO 3) 2 in the medium, elevated levels of lipid peroxides, increase in superoxide anion generation and a concomitant increase in the activities of guaiacol peroxidase and superoxide dismutase were noticed in Cd-grown seedlings compared to controls. Cd was freely absorbed by the rice plants and its level in rice shoots increased in parallel with its concentration in the growth medium. Under 500 μM Cd treatment about 1.4–1.6 times increase in malondialdehyde (MDA) levels indicating enhanced lipid peroxidation was noted in shoots of 20 days grown seedlings whereas under similar conditions nearly 0.8–1.7 times increase in superoxide anion (O 2 61) generation was observed in the seedling. With increase in Cd level in situ a marked elevation in superoxide dismutase (SOD) and peroxidase activities were observed. The increase in peroxidase activity was greater than SOD under Cd treatment. About 8–17 times higher level of peroxidase activity was recorded in the shoot of seedlings grown for 10 days under 500 μM Cd(NO 3) 2 compared to control grown seedlings. Higher level of peroxidase activity was observed in shoots than roots whereas higher SOD activity was noted in roots than shoots under both controls and Cd treatments. The activity of catalase increased in seedlings grown at moderately toxic Cd (100 μM) level whereas a highly toxic Cd (500 μM) level led to a marked inhibition in catalase activity. Results suggest that Cd induces oxidation stress in growing rice plants and that SOD and peroxidase could serve as important components of antioxidant defense mechanisms in rice to combat metal induced oxidative injury.
DOI:10.3864/j.issn.0578-1752.2011.02.017URLMagsci [本文引用: 3]
<P><FONT face=Verdana>【目的】研究铜离子对葡萄酒酿酒酵母的氧化胁迫作用,为葡萄酒酿造过程的铜离子控制提供依据。【方法】以模拟葡萄汁为酵母培养基,添加CuSO4分别设置0、0.05、0.10、0.20、0.50和1.00 mmol?L-1Cu2+浓度。另外设置0.50 mmol?L-1 H2O2的处理作为氧化胁迫的对比。【结果】铜胁迫下酿酒酵母细胞内超氧阴离子的产生速率和过氧化氢的含量增加。酿酒酵母膜脂过氧化程度加剧,细胞内丙二醛含量随着铜处理浓度的增加而增加。酿酒酵母细胞内超氧化物歧化酶和过氧化氢酶的活性在铜胁迫下有不同程度的升高。铜胁迫下谷胱甘肽和甘油在酿酒酵母细胞内大量积累。【结论】铜胁迫刺激酿酒酵母细胞内活性氧的形成,产生与过氧化氢类似的氧化胁迫,而且酵母细胞的抗氧化酶体系和非酶抗氧化系统可协同作用减少细胞受到的伤害。<BR></FONT></P>
DOI:10.3864/j.issn.0578-1752.2011.02.017URLMagsci [本文引用: 3]
<P><FONT face=Verdana>【目的】研究铜离子对葡萄酒酿酒酵母的氧化胁迫作用,为葡萄酒酿造过程的铜离子控制提供依据。【方法】以模拟葡萄汁为酵母培养基,添加CuSO4分别设置0、0.05、0.10、0.20、0.50和1.00 mmol?L-1Cu2+浓度。另外设置0.50 mmol?L-1 H2O2的处理作为氧化胁迫的对比。【结果】铜胁迫下酿酒酵母细胞内超氧阴离子的产生速率和过氧化氢的含量增加。酿酒酵母膜脂过氧化程度加剧,细胞内丙二醛含量随着铜处理浓度的增加而增加。酿酒酵母细胞内超氧化物歧化酶和过氧化氢酶的活性在铜胁迫下有不同程度的升高。铜胁迫下谷胱甘肽和甘油在酿酒酵母细胞内大量积累。【结论】铜胁迫刺激酿酒酵母细胞内活性氧的形成,产生与过氧化氢类似的氧化胁迫,而且酵母细胞的抗氧化酶体系和非酶抗氧化系统可协同作用减少细胞受到的伤害。<BR></FONT></P>
DOI:10.1016/S0162-0134(03)00182-XURLPMID:14507461 [本文引用: 1]
An aluminum (Al) tolerance mechanism, together with oxidative stress tolerance, was investigated in an Al tolerant cell line (ALT301) and the parental Al sensitive cell line (SL) of tobacco. During Al exposure in a simple calcium solution for 24 h, Al triggered the evolution of a reactive oxygen species (ROS) in SL much higher than ALT301 [Plant Physiol. 128 (2002) 63]. Under the conditions, Al enhanced comparable rates of citrate secretion from both cell lines to the same extent. Al enhanced the gene expression of manganese superoxide dismutase (MnSOD) in both cell lines, but at a significantly higher rate in SL than in ALT301, and also enhanced the enzyme activity of MnSOD in both cell lines to nearly the same level. These results suggest that the extracellular chelation of Al with organic acids and MnSOD is not involved in the mechanism of Al tolerance of ALT301. ALT301 contained ascorbate (ASA) and glutathione (GSH) levels that were higher than SL under normal growth conditions. During 24 h of post-Al treatment culture in growth medium, but not during 24-h Al exposure in a simple Ca 2+ solution, lipid peroxidation was enhanced in SL much higher than in ALT301, and the average SL amounts of ASA and GSH were exhausted compared to ALT301. Pre-loading of ASA prior to Al treatment improved the growth of SL during the post-Al treatment culture. ALT301 also exhibited cross-tolerance to H 2O 2, Fe 2+ and Cu 2+. Under these oxidant exposures, ALT301 contained lower levels of intracellular H 2O 2 or lipid peroxides, and maintained higher amounts of ASA and GSH than SL. Taken together, we conclude that the accumulation of Al in cells enhances the peroxidation of lipids exclusively under growing conditions, and that the higher content of ASA and GSH in ALT301 than in SL seems to be in part responsible for the tolerance mechanism of ALT301 to Al by protecting cells from either lipid peroxidation or H 2O 2 commonly enhanced by Al or other oxidants.
[D].
[本文引用: 1]
[D].
[本文引用: 1]
DOI:10.1007/s00709-013-0592-xURLPMID:24318675 [本文引用: 1]
Abstract Hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) function as the signaling molecules in plants responding to salt stresses. The present study presents a signaling network involving H2S and H2O2 in salt resistance pathway of the Arabidopsis root. Arabidopsis roots were sensitive to 100 mM NaCl treatment, which displayed a great increase in electrolyte leakage (EL) and Na(+)/K(+) ratio under salt stress. The treatment of H2S donors sodium hydrosulfide (NaHS) enhanced the salt tolerance by maintaining a lower Na(+)/K(+) ratio. In addition, the inhibition of root growth under salt stress was removed by H2S. Further studies indicated that H2O2 was involved in H2S-induced salt tolerance pathway. H2S induced the production of the endogenous H2O2 via regulating the activities of glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) NADPH oxidase, with the treatment with dimethylthiourea (DMTU, an ROS scavenger), diphenylene iodonium (DPI, a PM NADPH oxidase inhibitor), or glycerol (G6PDH inhibitor) removing the effect of H2S. Treatment with amiloride (an inhibitor of PM Na(+)/H(+) antiporter) and vanadate (an inhibitor of PM H(+)-ATPase) also inhibited the activity of H2S on Na(+)/K(+) ratio. Through an analysis of quantitative real-time polymerase chain reaction and Western blot, we found that H2S promoted the genes expression and the phosphorylation level of PM H(+)-ATPase and Na(+)/H(+) antiporter protein level. However, when the endogenous H2O2 level was inhibited by DPI or DMTU, the effect of H2S on the PM Na(+)/H(+) antiporter system was removed. Taken together, H2S maintains ion homeostasis in the H2O2-dependent manner in salt-stress Arabidopsis root.
DOI:10.1093/jxb/ert055URLPMID:3638822 [本文引用: 1]
Hydrogen sulfide (H2S) has been recently found to act as a potent priming agent. This study explored the hypothesis that hydroponic pretreatment of strawberry (Fragaria ananassa cv. Camarosa) roots with a H2S donor, sodium hydrosulfide (NaHS; 100 M for 48h), could induce long-lasting priming effects and tolerance to subsequent exposure to 100mM NaCI or 10% (w/v) PEG-6000 for 7 d. Hydrogen sulfide pretreatment of roots resulted in increased leaf chlorophyll fluorescence, stomatal conductance and leaf relative water content as well as lower lipid peroxidation levels in comparison with plants directly subjected to salt and non-ionic osmotic stress, thus suggesting a systemic mitigating effect of H2S pretreatment to cellular damage derived from abiotic stress factors. In addition, root pretreatment with NaHS resulted in the minimization of oxidative and nitrosative stress in strawberry plants, manifested via lower levels of synthesis of NO and H2O2 in leaves and the maintenance of high ascorbate and glutathione redox states, following subsequent salt and non-ionic osmotic stresses. Quantitative real-time RT-PCR gene expression analysis of key antioxidant (cAPX, CAT, MnSOD, GR), ascorbate and glutathione biosynthesis (GCS, GDH, GS), transcription factor (DREB), and salt overly sensitive (SOS) pathway (SOS2-like, SOS3-like, SOS4) genes suggests that H2S plays a pivotal role in the coordinated regulation of multiple transcriptional pathways. The ameliorative effects of H2S were more pronounced in strawberry plants subjected to both stress conditions immediately after NaHS root pretreatment, rather than in plants subjected to stress conditions 3 d after root pretreatment. Overall, H2S-pretreated plants managed to overcome the deleterious effects of salt and non-ionic osmotic stress by controlling oxidative and nitrosative cellular damage through increased performance of antioxidant mechanisms and the coordinated regulation of the SOS pathway, thus proposing a novel role for H2S in plant priming, and in particular in a fruit crop such as strawberry.
DOI:10.1016/j.plaphy.2013.07.021URLPMID:23974354 [本文引用: 2]
As a gaseous molecule, hydrogen sulfide (H2S) has been recently found to be involved in plant responses to multiple abiotic stress. In this study, salt (150 and 300 mM NaCl), osmotic (15% and 30% PEG6000) and cold (4 degrees C) stress treatments induced accumulation of endogenous H2S level, indicating that H2S might play a role in bermudagrass responses to salt, osmotic and cold stresses. Exogenous application of H2S donor (sodium hydrosulfide, NaHS) conferred improved salt, osmotic and freezing stress tolerances in bermudagrass, which were evidenced by decreased electrolyte leakage and increased survival rate under stress conditions. Additionally, NaHS treatment alleviated the reactive oxygen species (ROS) burst and cell damage induced by abiotic stress, via modulating metabolisms of several antioxidant enzymes [catalase (CAT), peroxidase (POD) and GR (glutathione reductase)] and non-enzymatic glutathione antioxidant pool and redox state. Moreover, exogenous NaHS treatment led to accumulation of osmolytes (proline, sucrose and soluble total sugars) in stressed bermudagrass plants. Taken together, all these data indicated the protective roles of H2S in bermudagrass responses to salt, osmotic and freezing stresses, via activation of the antioxidant response and osmolyte accumulation. These findings might be applicable to grass and crop engineering to improve abiotic stress tolerance. (C) 2013 Elsevier Masson SAS. All rights reserved.
DOI:10.1088/0256-307X/18/11/313URL [本文引用: 1]
中国科学院机构知识库(CAS IR GRID)以发展机构知识能力和知识管理能力为目标，快速实现对本机构知识资产的收集、长期保存、合理传播利用，积极建设对知识内容进行捕获、转化、传播、利用和审计的能力，逐步建设包括知识内容分析、关系分析和能力审计在内的知识服务能力，开展综合知识管理。
DOI:10.1088/0256-307X/18/11/313URL [本文引用: 1]
中国科学院机构知识库(CAS IR GRID)以发展机构知识能力和知识管理能力为目标，快速实现对本机构知识资产的收集、长期保存、合理传播利用，积极建设对知识内容进行捕获、转化、传播、利用和审计的能力，逐步建设包括知识内容分析、关系分析和能力审计在内的知识服务能力，开展综合知识管理。
URL [本文引用: 1]
In comparison with normal plants, hyperaccumulators have the ability to accumulate heavy metals in their shoots far exceeding those observed in soil, without suffering from detrimental effects.With the help of molecular technologies, the research on the mechanisms of heavy metal accumulation in hyperaccumulators has been made a great progress. Anumber of trace element transporters have been cloned by functional complementation with yeast mutants defective in metal absorption. The relations between glutathione, phytochelatins metallothioneins, organic acids and heavy metals have been studied by molecular technologies. This review concentrated on the physiological and molecular mechanisms of heavy metal absorption and sequestration in hyperaccumulators.
URL [本文引用: 1]
In comparison with normal plants, hyperaccumulators have the ability to accumulate heavy metals in their shoots far exceeding those observed in soil, without suffering from detrimental effects.With the help of molecular technologies, the research on the mechanisms of heavy metal accumulation in hyperaccumulators has been made a great progress. Anumber of trace element transporters have been cloned by functional complementation with yeast mutants defective in metal absorption. The relations between glutathione, phytochelatins metallothioneins, organic acids and heavy metals have been studied by molecular technologies. This review concentrated on the physiological and molecular mechanisms of heavy metal absorption and sequestration in hyperaccumulators.
URL [本文引用: 1]
The biosynthesis pathway of phytochelatins (PC) and its function in heavy metal tolerance of higher plants were summarized in this paper. The toxic heavy metal accumulation in soil would deteriorates crop growth and yield components, and threaten the agro-products security. There were significantly differences in the accumulation and tolerance to heavy metals among plant species and genotypes. The formation of PCin response to the stress caused by heavy metals was one of the truly adaptive responses occurred commonly in higher plants. In the heavy metal tolerant genotypes, there was a much higher accumulation of PCthan the non-tolerant lines. Glutathione (GSH) was the substrate for the synthesis of PC, which chelated the metals. The inactive toxic metal ions of metal-PC chelatins were subsequently transported from cytosol to vacuole before they could poison the enzymes of life-supporting metabolic routes, and transiently stored in vacuole to reduce the heavy metal concentration in cytosol, thus, heavy metal detoxification was attained. The break through of genetic mechanism and bio-chemical pathway of PC synthesis induced by heavy metals would depend on the further study on molecular biology in this field. The isolation of Cd-sensitive 1 and 2 mutants of Arabidopsis thaliana, that was deficient in PC, demonstrted the importance of PCfor heavy metal tolerance. The effect of PC on food security and on phytoremediation of soil and water contaminated by heavy metals was also discussed in this paper.
URL [本文引用: 1]
The biosynthesis pathway of phytochelatins (PC) and its function in heavy metal tolerance of higher plants were summarized in this paper. The toxic heavy metal accumulation in soil would deteriorates crop growth and yield components, and threaten the agro-products security. There were significantly differences in the accumulation and tolerance to heavy metals among plant species and genotypes. The formation of PCin response to the stress caused by heavy metals was one of the truly adaptive responses occurred commonly in higher plants. In the heavy metal tolerant genotypes, there was a much higher accumulation of PCthan the non-tolerant lines. Glutathione (GSH) was the substrate for the synthesis of PC, which chelated the metals. The inactive toxic metal ions of metal-PC chelatins were subsequently transported from cytosol to vacuole before they could poison the enzymes of life-supporting metabolic routes, and transiently stored in vacuole to reduce the heavy metal concentration in cytosol, thus, heavy metal detoxification was attained. The break through of genetic mechanism and bio-chemical pathway of PC synthesis induced by heavy metals would depend on the further study on molecular biology in this field. The isolation of Cd-sensitive 1 and 2 mutants of Arabidopsis thaliana, that was deficient in PC, demonstrted the importance of PCfor heavy metal tolerance. The effect of PC on food security and on phytoremediation of soil and water contaminated by heavy metals was also discussed in this paper.
[D].
[本文引用: 1]
[本文引用: 1]
DOI:10.1016/S1360-1385(97)01019-4URL [本文引用: 1]
Plants have versatile detoxification systems to counter the phytotoxicity of the wide variety of natural and synthetic chemicals - xenobiotics - present in the environment. One important detoxification mechanism is chemical modification of the xenobiotic by covalent linkage to the endogenous tripeptide, glutathione. The resulting glutathione conjugates are exported from the cytosol to the vacuole by an ATP-dependent tonoplast transporter. This detoxification pathway shares many features with the pathway used by plants for the synthesis and vacuolar deposition of secondary metabolites, such as anthocyanins. In addition, the vacuolar glutathione-conjugate transporter shows functional similarities with an ATP-binding cassette transporter, the multidrug resistance-associated protein, present in drug-tolerant human cancer cells.
DOI:10.1105/tpc.104.023036URLPMID:15269333 [本文引用: 1]
http://www.plantcell.org/cgi/doi/10.1105/tpc.104.023036
DOI:10.1146/annurev.arplant.53.100301.135154URL [本文引用: 1]
DOI:10.1093/jexbot/53.372.1283URLPMID:11997376 [本文引用: 1]
Abstract Glutathione has numerous roles in cellular defence and in sulphur metabolism. These functions depend or impact on the concentration and/or redox state of leaf glutathione pools. Effective function requires homeostatic control of concentration and redox state, with departures from homeostasis acting as signals that trigger adaptive responses. Intercellular and intracellular glutathione pools are linked by transport across membranes. It is shown that glutathione can cross the chloroplast envelope at rates similar to the speed of biosynthesis. Control of glutathione concentration and redox state is therefore due to a complex interplay between biosynthesis, utilization, degradation, oxidation/reduction, and transport. All these factors must be considered in order to evaluate the significance of glutathione as a signalling component during development, abiotic stress, or pathogen attack.
[本文引用: 1]
DOI:10.1016/0014-5793(95)00603-7URLPMID:7615092 [本文引用: 1]
Abstract Role of intracellular glutathione in the response of Saccharomyces cerevisiae to H2O2 was investigated. Depletion of cellular glutathione or inhibition of gamma-glutamylcysteine synthetase (GSH-I) enhanced the sensitivity to H2O2 and suppressed the adaptation to H2O2. A mutant deficient in GSH-I also showed the hypersensitivity and could not adapt to H2O2. Incubation of the cell with amino acids constituting glutathione (L-Glu, L-Cys, Gly) increased the intracellular glutathione content, and subsequently the cell acquired resistance against H2O2. These results strongly suggest that intracellular glutathione plays an important role in the adaptive response in S. cerevisiae to oxidative damage.
[本文引用: 1]
.
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
DOI:10.1007/BF02535999URL [本文引用: 1]
A kinetic study on the prooxidant effect of vitamin E derivatives has been carried out. Rates of hydrogen abstraction from various fatty acids and egg yolk lecithin by tocopheroxyl radicals were determined spectrophotometrically. The rate constants measured in micellar dispersion were compared with those obtained in homogeneous solutions. The effects of structural variations of the vitamin E derivatives on their prooxidant activities were examined. The formation of lecithin reverse micelles in benzene appears to prevent the tocopheroxyl radicals from reacting with the phospholipid fatty acid moieties.
