诱导子对藏红花悬浮培养细胞生产藏红花色素的影响

考察壳聚糖（chitosan）、壳寡糖（chitosanoligosaccharides,COS）、茉莉酸甲酯（methyljasmonate,MJ）、水杨酸（salicylicacid,SA）和Cu2＋等诱导子对藏红花悬浮培养细胞生长和藏红花色素合成的影响。结果表明：在实验考察浓度范围内,壳寡糖（1～500mg／L）和较低浓度壳聚糖（≤10mrdL）、MJ（≤10μmol／L）、SA（≤10μμmol／L）和Cu2＋（≤1μmoL／L）对细胞生长无显著影响;较高浓度壳聚糖（≥100mg／L）、MJ（≥100μmol／L）、SA（≥100μmoL／L）和cu“（≥10μmoL／L）显著抑制细胞生长。5种诱导子对藏红花色素合成的诱导效果不同,并且与诱导子作用浓度和添加时间有关。MJ诱导效果最好,在细胞培养第0天添加终浓度100仙moL／LMJ,藏红花色素含量（以1克干细胞计）达到28．57mg,比对照提高177．9％。其次是cu“,在细胞培养第4天添加终浓度500μmoL／LCu2＋,色素含量达到19．82mg,比对照提高108．2％。再次是壳聚糖和壳寡糖,在细胞培养第14天分别添加终质量浓度100mg／L壳聚糖和壳寡糖,色素含量分别达到18．33和17．39mg,比对照提高69．1％和69．0％。最后是SA,在细胞培养第14天添加终浓度10μmoL／LSA,色素含量达到14．65mg,比对照提高45．4％。     

茉莉酸甲酯和水杨酸对西洋参愈伤组织生长和皂苷形成的影响CSCD

本文旨在探究不同诱导子对西洋参愈伤组织生长、相关酶活性及其人参皂苷含量的影响,在西洋参愈伤组织中,应用HPLC检测了添加诱导子茉莉酸甲酯(methyl jasmonate,MeJA)和水杨酸(salicylic acid,SA)后西洋参愈伤组织皂苷生物合成的变化。结果显示,MeJA抑制生长,但SA对其生长影响较小;2种诱导子均可以显著激活西洋参愈伤组织中超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)活性和丙二醛(malondialdehyde,MDA)含量;培养基中MeJA浓度为100μmol/L时,愈伤组织中总皂苷含量和产量均达到最大值,人参皂苷Rg_(1)、Re、Rb_(1)、Rc的含量最高,在SA诱导子试验组中,当SA浓度为300μmol/L时,西洋参愈伤组织中总皂苷含量和产量均达到最大值,人参皂苷Rb_(1)的含量最高。结果表明,在西洋参愈伤组织中添加适当浓度MeJA和SA诱导子会提高人参皂苷化合物含量,其中以MeJA诱导人参总皂苷的效果最好,同时也会影响西洋参愈伤组织的生长量。说明在培养过程中添加外源诱导子,有利于提高西洋参愈伤组织中皂苷含量。     

细胞均一性对葡萄细胞生长和花青素合成的影响

通过色差筛选法建立了一个相对均一的葡萄细胞悬浮系E,其细胞团较小,在长期继代培养过程中花青素合成能力的变异系数为8.7%,重复摇瓶实验的变异系数为5%。以E为实验材料进行的各组前体饲喂、诱导子添加、光照等联合作用实验,其生物量和花青素合成的变异系数均可控制在12%以内,充分说明了培养体系的均一性对维持稳定生产的重要性;黑暗条件下添加30μmol/L苯丙氨酸(Phe)和218μmol/L茉莉酸甲酯(MeJA)可使单位细胞花青素含量达到对照组的5.89倍,花青素产量为对照组的4.30倍,且连续5次继代培养过程中生物量和花青素合成的变异系数均比对照组降低。     

北柴胡不定根培养及茉莉酸甲酯处理对柴胡皂苷含量的影响

目的:建立北柴胡不定根培养体系,明确茉莉酸甲酯(MeJA)处理对北柴胡不定根中柴胡皂苷含量积累的影响。方法:利用固体和液体相结合的组织培养技术培养北柴胡不定根;分别以不同浓度的MeJA处理不定根不同时间,利用HPLC测定处理后不定根中柴胡皂苷含量的积累变化。结果:培养了北柴胡不定根;MeJA处理对北柴胡不定根中柴胡皂苷含量的积累有明显促进作用,当MeJA浓度为200μmol/L时,柴胡皂苷含量最高,为0.45%;以200μmol/L MeJA处理北柴胡不定根26 d时,柴胡皂苷含量最高,为0.51%。结论:北柴胡不定根培养结合MeJA诱导,可做为柴胡皂苷次生代谢合成途径及其积累规律研究的有效技术体系。     

锌协同三羟异黄酮对成骨细胞MC3T3-E1的影响

目的:观察锌协同三羟异黄酮对成骨细胞MC3T3-E1增殖、细胞中碱性磷酸酶(ALP)含量、骨形成蛋白-2(BMP-2)表达的影响,探讨锌协同三羟异黄酮对骨质疏松的防治作用.方法:采用四甲基偶氮噻唑蓝比色法检测(1×10-7)mol/L、(1×10-6)mol/L、(1x 10-5)mol/L、(1×10-4)mol/L的三羟异黄酮以及与(1×10-5)mol/L锌联合作用时对MC3T3-E1增殖的作用;应用Western blot法检测三羟异黄酮与锌联合作用前后,成骨细胞中BMP-2蛋白的表达水平,用比色法检测MC3T3-E1中ALP的含量.结果:锌与三羟异黄酮单独作用或协同作用于MC3T3-E1细胞,其增殖率随着三羟异黄酮浓度的增加和作用时间的延长而升高,(1×10-5)mol/L的三羟异黄酮协同(1×10-5)mol/L的锌作用72h,其细胞增殖率为(160.1±14.3)%.细胞中的LP含量及BMP-2的表达也随着三羟异黄酮浓度的增加及作用时间的延长而增加.三羟异黄酮和锌联合作用后,对ALP活性的增强、BMP-2表达的增加作用均较各自单独作用时更为明显(P＜0.05).结论:三羟异黄酮与锌协同作用表现出雌激素效应,可通过促进骨形成蛋白的合成从而促进成骨细胞的增殖、增加骨量.     

外源MeJA胁迫对盐生杜氏藻生理生化特性的影响

研究外源茉莉酸甲酯(MeJA)对盐生杜氏藻细胞β-胡萝卜素含量、叶绿素含量、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性的影响。结果表明,当外源MeJA浓度为0～100μmol/L时,随着MeJA浓度的升高,β-胡萝卜素和叶绿素含量呈上升趋势,当MeJA浓度为100μmol/L时,盐生杜氏藻β-胡萝卜素和叶绿素含量最高,当MeJA处理浓度大于100μmol/L时,盐生杜氏藻β-胡萝卜素和叶绿素含量逐渐降低。生理生化结果分析表明,外源MeJA处理可提高盐生杜氏藻POD酶和SOD酶活性,随着MeJA浓度的增加,SOD酶活性呈逐渐上升的趋势,POD酶活性呈先上升后下降的趋势,与β-胡萝卜素含量、叶绿素含量的变化趋势基本一致,说明外源MeJA处理可诱导盐生杜氏藻β-胡萝卜素积累可能与叶绿素含量、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性有关。     

激发子对桦褐孔菌多酚合成的诱导及其生化机制初探

旨在研究真菌激发子对桦褐孔菌多酚合成的影响,采用液体摇瓶培养方式,将真菌激发子加入到桦褐孔菌液体培养物中,检测桦褐孔菌次级代谢产物的积累,以及真菌激发子对桦褐孔菌一氧化氮合酶(NOS)活性的影响。结果表明,适量添加真菌激发子能够提高桦褐孔菌的代谢速率,提高多酚类化合物的合成,胞内和胞外多酚最高可达102.15 mg/L和311.91 mg/L,并能显著提高桦褐孔菌NOS的活性,其活性最高可达151.93 U/mg prot,发酵液一氧化氮(NO)含量最高可达256.28μmol/L。这表明,真菌激发子能够有效激活桦褐孔菌的次级代谢产物合成途径。     

水杨酸对干旱胁迫下西洋参不定根生化指标及药用成分含量的影响

为探讨西洋参不定根对干旱胁迫的应答机制及外源水杨酸(SA)对西洋参不定根抗旱性的影响，本研究使用质量分数为10%的PEG-6000模拟干旱胁迫预处理，然后添加不同浓度(0,10,40,80μmol/L)的外源SA,分别在处理2、4、6、8 d时检测西洋参不定根中抗氧化酶活性、渗透调节物质含量以及药用成分总黄酮、总皂苷、单体皂苷Rb1和Re的积累量，并检测人参皂苷生物合成途径中相关合成和调控基因的表达量。结果显示：(1)西洋参不定根中过氧化氢酶(CAT)和过氧化物酶(POD)活性以及游离脯氨酸含量均在80μmol/L SA处理4 d时出现峰值，而丙二醛(MDA)含量在40μmol/L SA处理4 d时达到峰值。(2)西洋参不定根中总黄酮的含量在80μmol/L SA处理6 d时达到最大值，总皂苷和单体皂苷Re含量在40μmol/L SA处理8 d时达到最大值，单体皂苷Rb1含量在40μmol/L的SA处理6 d时达到最大值。(3)Pq-HMGR和Pq-DS基因表达量在40μmol/L SA处理2 d时提高了3倍以上，Pq-CYP6H、Pq-D12H、Pq-3-O-UGT1和Pq-bHLH...     

水杨酸诱导美登木悬浮细胞产生脂氧合酶及多羟基脂肪酸的研究

水杨酸 (SA)可诱导云南美登木 (Maytenushookeri)悬浮培养细胞产生 9 脂氧合酶(9 lipoxygenase ,9 LOX)。通过LC ESI MS测定SA诱导下悬浮培养系中多羟基脂肪酸的含量变化 ,发现用浓度为 80 0 μmol L的SA诱导培养 18h ,悬浮细胞产生最大量的三羟基十八碳烯酸。同时 ,通过对比不同羟基十八碳烯酸含量的变化 ,推测在SA诱导下 ,9 LOX介导的十八碳酸途径中有环氧中间体的生成。     

水杨酸对丹参培养细胞中迷迭香酸生物合成及其相关酶的影响

迷迭香酸(RA)是丹参中一种重要的酚酸类次生代谢物。为探讨水杨酸(SA)诱导子对丹参悬浮培养细胞中RA的生物合成及其相关酶的影响,考察了SA诱导子和酪氨酸氨基转移酶(TAT)的竞争性抑制剂(AOPP)对RA合成积累量、苯丙氨酸解氨酶(PAL)和TAT活性的影响。发现在培养的第6天用浓度为6.25 mg/L的SA处理后,PAL活性在诱导后4 h出现高峰,为对照组水平的124%;RA的积累量在诱导后8 h出现峰值(5.914±0.296)mg/g。用浓度为0.1μmol/L的AOPP处理,6 h后AOPP对TAT活性影响较小(与对照组无显著差异),但明显抑制了PAL活性(为对照组水平的44%),且在PAL活性明显降低的同时RA的积累量显著减少(4.709±0.204)mg/g。进一步用0.1μmol/L AOPP和6.25 mg/L SA共处理,AOPP对PAL的抑制作用可得到一定程度的缓解,且RA的积累量较AOPP单独处理的高。表明SA可以诱导丹参悬浮培养细胞中RA积累量的增加,且在RA合成过程中PAL的限速作用比TAT明显。     

诱导子对百里香再生植株中苯丙氨酸解氨酶活性的影响

以1/2MS为基本培养基,分别用蔗糖、NO3-/NH4+、苯丙氨酸、谷氨酸和酪氨酸诱导培养百里香组培苗30d,以及茉莉酸甲酯(MeJA)、水杨酸(SA)和壳聚糖诱导培养百里香20、30和40d组培苗植株0～120h,在不同的时间点测定其苯丙氨酸解氨酶(PAL)活性,以探讨诱导子对增殖百里香中PAL活性的影响。结果显示:以1/2MS为基本培养基,碳氮源调控30d后,百里香组培株的PAL活性以蔗糖浓度为2%、NO3-/NH4+比例为2∶1时最高;前体调控添加0.6mmol/L苯丙氨酸、0.8mmol/L谷氨酸和0.4mmol/L酪氨酸处理的百里香组培苗的PAL活性最高,分别为相应对照的126.3%、150.6%和153.9%。培养20d和30d植株的PAL活性均以1.0mmol/L MeJA、100mg/L SA和200mg/L壳聚糖诱导处理的最高,分别为相应对照的610.3%、788.1%、592.5%以及402.4%、541.2%、400.1%;而40d植株经0.5mmol/L MeJA、100mg/L SA和200mg/L壳聚糖诱导的PAL活性最高,分别为对照的390.2%、377.1%和413.4%。可见,在不同时期添加不同的诱导子对百里香再生植株中PAL活性有显著影响,且不同材料和诱导子存在各自适宜的诱导浓度和最佳诱导时间。     

Elicitation of anthocyanin production in callus cultures of <Emphasis Type="Italic">Daucus carota</Emphasis> and the involvement of methyl jasmonate and salicylic acid

The effect of methyl jasmonate (MeJA) and salicylic acid (SA) on the anthocyanin accumulation, endogenous titres of polyamines and ethylene production in callus cultures of Daucus carota were studied. The interaction of these signaling molecules with elicitors from Aspergillus niger was investigated and the involvement of MeJA was elucidated through the use of the jasmonic acid (JA) biosynthetic inhibitor ibuprofen. MeJA and SA were both found to stimulate the anthocyanin production in the callus cultures. The highest levels of anthocyanin was observed in the cultures treated with 200 μM SA 0.36 % and 0.01 μM MeJA 0.37 %. The MeJA and SA treatments were also found to result in higher activity of Ca²⁺ ATPase suggesting that the enhancement of anthocyanin by SA and MeJA could be mediated through the involvement of the calcium channel. The treatment of the callus cultures with SA was found to result in marginally higher titres of endogenous polyamines (PAs) whereas MeJA resulted in lower levels of PAs as compared to the control. The SA treatment was found to result in lower ethylene production and the treatment with MeJA stimulated the ethylene production. These results suggest that the stimulation of anthocyanin production by MeJA and SA in callus cultures of D. carota is not related to the ethylene production.     

Differential Response of Floret Opening in Male-Sterile and Male-Fertile Rices to Methy Jasmonate

Effects of methyl jasmonate (MeJA) on floret opening were investigated in male-sterile and male-fertile rice ( Oryza sativa subsp. indica ). Excised or intact panicles with several top florets flowered one day before the experiments were soaked in MeJA, salicylic acid (SA), 24-epibrassinolide (24-epiBL) or control solution for 2 min. MeJA at the concentration of 4 mmol/L significantly promoted rice floret opening; the response of floret opening of male-sterile rice to MeJA was more sensitive than that of male-fertile rice (such as maintenance line and conventional variety). The percentage of finally opened-floret per panicle of Zhenshan 97A (cytoplasmic male sterile line) or Pei'ai 64S (thermo-sensitive genic male sterile line) treated with MeJA was over 40% in the day of experiment, that of Zhenshan 97B (maintenance) and Pei'ai 64 (conventional variety) was (21±1.5)% and (25±2.1)%, respectively; floret opening of intact Pei'ai 64S panicles in the field could also be induced by 2-mmol/L MeJA. The percentage of opened floret in all control panicles was 0% or less than 5% in the day of experiment. The percentage of fertilized-grain of Zhenshan 97A and Longtepu A could be increased over 24% by spraying panicles with 2-mmol/L MeJA solution （circa 6.0 μmol per panicle）. The lag time (time from the finishing of treatment to first floret opening) of male sterile line responsing to MeJA was 10 min shorter than that of male fertile line. MeJA induction on the rice floret opening could markedly be inhibited by SA solution at the concentration of 1 mmol/L, and the inhibition of SA on MeJA induction on floret opening of male-sterile rice could be nullified by MeJA treatment again. MeJA effect on floret opening of male-sterile rice could be clearly synergized by pretreatment with 24-epibrassinolide (24-epiBL).     

The Response of Physiological Characteristics,Expression of OSC Genes,and Accumulation of Triterpenoids in <Emphasis Type="Italic">Betula platyphylla</Emphasis> Sukto MeJA and SA Treatment

The pentacyclic triterpenoids from birch (Betula platyphylla suk) have broad pharmacological activities and can be potentially used for the development of anti-cancer and anti-AIDS drugs. In this study, we explored the effects of spraying 3-year-old white birch with different concentration of methyl jasmonate (MeJA) and salicylic acid (SA) on the expression of key genes in triterpenoid biosynthesis pathways and on the accumulation and physiological characteristics of triterpenoids in birch saplings. The results showed that spraying different concentration of MeJA and SA could obviously promote accumulation of total triterpenoids in 3-year-old white birch. The triterpenoid content in the stem bark was increased by 46.11 %, reaching 81.86 mg/g, after 1 day of treatment with 1 mmol·L^?1 MeJA (MJ2), and by 45.07 %, reaching 91.4 mg/g, after 14 days of treatment with 5 mmol·L^?1 SA (SA1). In addition, MeJA and SA treatment increased the contents of chlorophyll a and b, antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as photosynthetic performance, and affected the content of soluble sugar and soluble protein in birch leaf. Fluorescence quantitative polymerase chain reaction (qPCR) results showed that MeJA and SA treatment deferentially enhanced the key gene expression of cycloartenol synthase (BPX and BPX2), lupeol synthase (BPW) and beta-amyrin synthase (BPY) in triterpenoid synthesis pathway in birch bark and leaves. The results showed that MeJA and SA induced triterpenoid synthesis of birch plant is closely related with not only the expression of key genes of triterpenoid synthesis pathway but also photosynthesis, anti-stress response and physiological indexes, suggesting that regulation of triterpenoid synthesis of birch by MeJA and SA may involve in more complex mechanisms at physiological and molecular levels.     

Effect of sucrose and methyl jasmonate on biomass and anthocyanin production in cell suspension culture of Melastoma malabathricum (Melastomaceae)

Melastoma malabathricum, belongs to the Melastomaceae family, is an important medicinal plant widely distributed from Madagascar to Australia, that is used in traditional remedies for the treatment of various ailments. Besides its medicinal properties, it has been identified as a potential source of anthocyanin production. The present study was carried out to investigate the effect of sucrose and methyl jasmonate and feeding time on cell biomass yield and anthocyanin production in cell suspension culture of M. malabathricum. Addition of different concentrations of sucrose into the cell culture of M. malabathricum influenced cell biomass and pigment accumulation. The addition of methyl jasmonate was found to have no effect on cell biomass but the presence of higher amount (12.5-50 mg/L) had caused a reduction in anthocyanin production and accumulation. MS medium supplemented with 30 g/L sucrose and 3.5 mg/L of MeJA added on cero day and 3rd day produced high fresh cell mass at the end of nine days of culture but did not support the production of anthocyanins. However, cells cultured in the medium supplemented with 45 g/L sucrose without MeJA showed the highest pigment content (0.69 +/- 0.22 CV/g-FCM). The cells cultured in MS medium supplemented with 30 g/L sucrose with 3.5 mg/L MeJA added on the 3rd and 6th day of culture, showed the lowest pigment content (0.37-0.40 CV/g-FCM). This study indicated that MeJA was not necessary but sucrose was needed for the enhancement of cell growth and anthocyanin production in M. malabathricum cell cultures.     

Induction of pathogen resistance and pathogenesis-related genes in tobacco by a heat-stable Trichoderma mycelial extract and plant signal messengers

Heat-stable mycelial extracts of the nonpathogenic fungus Trichoderma longibrachiatum induced resistance in tobacco seedlings ( Nicotiana tabacum L. cv. Wisconsin 38) to the pathogen Phytophthora parasitica var. nicotianae (race 0), which did not involve a hypersensitive response. Resistance could not be induced with mycelial extract prepared in the same manner from P. parasitica . The nonpathogenic mycelial extract induced expression of PR-1b and osmotin (PR-5) genes to a higher level than did mycelial extract from the pathogenic fungus. The tissue-specific pattern of PR gene induction by the nonpathogenic mycelial extract was different from that of the pathogenic mycelial extract and was consistent with the ability of the former to cause disease resistance. The expression patterns of these two PR genes and the accumulations of their encoded proteins also were affected by salicylic acid (SA), methyl jasmonate (MeJA), ethylene (E) and combinations of these plant signal messengers. However, only combined SA and MeJA treatment mimicked the pattern of PR gene mRNA and protein accumulation induced by the nonpathogenic mycelial extract. E inhibitors blocked both mycelial extract-induced and SA/MeJA-induced PR gene expression, and the cis pattern of responsiveness on the osmotin promoter was the same for the mycelial extract, SA, E, or E/MeJA. Seedlings treated with P. parasitica spores in the presence of SA/MeJA were protected from pathogen colonization. However, these seedlings exhibited symptoms of cell death (disease symptoms) both in the absence and presence of P. parasitica spores, in contrast to seedlings treated with nonpathogenic mycelial extract, which remained healthy. These results suggest that the signal transduction pathways for elicitation of defense responses by exogenously applied heat-stable nonpathogenic mycelial extract and SA/MeJA overlap at the point of PR protein induction but are not identical.     

The 9-lipoxygenase GhLOX1 gene is associated with the hypersensitive reaction of cotton Gossypium hirsutum to Xanthomonas campestris pv malvacearum.

Hypersensitive reaction (HR) cell death of cotton to the incompatible race 18 from Xanthomonas campestris pathovar malvacearum (Xcm) is associated with 9S-lipoxygenase activity (LOX) responsible for lipid peroxidation. Here, we report the cloning of cotton (Gossypium hirsutum L.) LOX gene (GhLOX1) and the sequencing of its promoter. GhLOX1 was found to be highly expressed during Xcm induced HR. Sequence analysis showed that GhLOX1 is a putative 9-LOX, and GhLOX1 promoter contains SA and JA responsive elements. Investigation on LOX signalisation on cotyledons infiltrated with salicylic acid (SA), or incubated with methyl-jasmonate (MeJA) revealed that both treatments induced LOX activity and GhLOX1 gene expression. HR-like symptoms were observed when LOX substrates were then injected in treated (MeJA and SA) cotyledons or when Xcm compatible race 20 was inoculated on MeJA treated cotyledons. Together these results support the fact that GhLOX1 encodes a 9 LOX whose activity would be involved in cell death during cotton HR.     

不同诱导因子对落叶松毛虫嗅觉和产卵选择的影响

试验测定了落叶松毛虫幼虫和成虫对茉莉酮、茉莉酸甲酯和水杨酸甲酯3种挥发性信号化合物以及对剪叶损伤、昆虫取食、茉莉酸和水杨酸等诱导因子处理的兴安落叶松的行为反应.结果表明:在0.1%～10% V/V浓度下,茉莉酸甲酯和水杨酸甲酯对幼虫有驱避作用;机械损伤、茉莉酮、茉莉酸、茉莉酸甲酯和水杨酸甲酯均能诱导落叶松产生防御,明显减少了幼虫的取食选择.落叶松毛虫成虫对茉莉酮和水杨酸甲酯有明显的触角电位反应,且雌虫反应敏感性随浓度增加而增强.在诱导因子处理后的落叶松上,成虫产卵量明显减少.     

Zinc pretreatment prevents hepatic stellate cells from cadmium-produced oxidative damage

Pretreatment with zinc produces tolerance to several cadmium toxic effects. This study was performed to further elucidate the mechanism of zinc-induced tolerance to cadmium cytotoxicity in a rat hepatic stellate cell line (CFSC-2G). Twenty four hours after seeding, cells were treated with 60 micromol/L ZnCl2 for 24 h. Following zinc pretreatment, cells were exposed to 3 micromol/L and 5 micromol/L CdCl2 for an additional 24 h. The toxicity of cadmium was significantly reduced in the zinc-pretreated cells. Zinc pretreatment produced a decrease in lipid peroxidation damage of cadmium-treated cells. Glutathione cell content diminished 33% and 43% as a result of 3 micromol/L and 5 micromol/ L CdCl2 treatment, respectively. Cell pretreatment with zinc recovered glutathione content at control cells level. Catalase and glutathione peroxidase activities were also recovered to control values with zinc pretreatment. Cadmium (5 micromol/L) was able to induce 39% the expression of alpha1 collagen (I) gene after 1 h treatment, while zinc pretreatment prevented this cadmium profibrogenic effect. We also examined the production of heat shock protein 70 (Hsp70) as a cellular response to oxidative stress produced by cadmium. By Western blot analysis, a 1.3 and 3 times increment in Hsp70, with 3 micromol/L and 5 micromol/L CdCl2 treatment, respectively, was observed. Zinc pretreatment prevented the production of Hsp70. Metallothionein-II (MT-II) gene expression was induced by cadmium, but the induction was unaffected with zinc pretreatment. These data suggest that zinc-induced protection against the cytotoxicity of cadmium in stellate cells may be related to the maintenance of normal redox balance inside the cell.