Cadmium Accumulation and Tolerance of Two Safflower Cultivars in Relation to Photosynthesis and Antioxidantive Enzymes

To investigate the effects of cadmium (Cd) on photosynthetic and antioxidant activities of safflower (Carthamus tinctorius L.) plants, two cultivars (Yuming and New safflower No. 4) were used for long-term pot experiment, under 0, 25, 50 or 100 mg Cd kg⁻¹ (DW) soil conditions. The results showed that there is a large amount of Cd (148.6–277.2 mg kg⁻¹) accumulated in the shoot of safflower, indicating this species might be a potential Cd accumulator. Exposure to 25–100 mg Cd kg⁻¹ soil decreased the net photosynthetic rate by 25.6%–48.9% for New safflower No. 4, and 16.7%–57.3% for Yuming, respectively. The inhibition of photosynthesis might result from the limitation of stomatal conductance, reduction in photosynthetic pigment, and destruction of photosynthetic apparatus caused by Cd stress. Cd caused an enhancement of malondialdehyde (MDA), an increase in activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX), and a decrease in catalase (CAT) activity for both cultivars. It seems that SOD and APX accounted for the scavenging of oxidant stress in safflower cultivars. The physiological response of safflower plants to Cd stress was cultivar- and dose- dependent. New safflower No. 4 exhibited high photosynthetic performance at high Cd stress, which may be contributed by high intercellular CO₂ concentration, APX activity and Car/Chl ratio. In contrast, Yuming is more tolerant to Cd toxicity at low Cd level, in which an efficient antioxidant system is involved.     

Effect of Cadmium Accumulation on Anti-Inflammatory Activity in Two Eucomis Species

Eucomis species (Hyacinthaceae) are widely used in South Africa as traditional medicine. The bulbs are used to alleviate a variety of symptoms including pain and inflammation. High levels of cyclooxygenase-1 and -2 (COX-1 and COX-2) inhibitory activity have been associated with certain Eucomis species. The aim of this study was to quantify cadmium (Cd) accumulation and examine its effect on COX-1 and COX-2 anti-inflammatory activity in Eucomis autumnalis and Eucomis humilis. Cadmium application at 2 mg L⁻¹ over a 6 week period revealed a substantial difference in total Cd accumulation in E. autumnalis and E. humilis (40.2 and 15.3 mg Cd kg⁻¹, respectively). When supplied with Cd at 2 mg L⁻¹, E. humilis bulbous extracts showed lower inhibitory activity than the control for both COX-1 and COX-2. E. autumnalis bulbous extracts had greater COX-1 activity compared to the control. While COX-2 activity was suppressed. Researchers should be aware of the effect of environmental contaminants when reporting on biological activity of crude plant extracts.     

Metal Accumulation in Cell Wall: A Possible Mechanism of Cadmium Resistance by Pseudomonas stutzeri

A heavy metal resistant strain, Pseudomonas stutzeri (MTCC 101) has been investigated for its cadmium tolerance properties along with its antibiotic resistance. The organism could tolerate cadmium up to 1,200 μg/mL with LD₅₀ value 700 μg/mL. The gene(s) involved in such high resistance appear(s) to be induced in the presence of the metal. Increasing concentrations of cadmium successively prolonged the lag phase of growth with delayed attainment of the stationary phase. Transmission electron microscope and scanning electron microscope–energy dispersive analysis of X-ray spectroscope analysis showed cadmium adsorption on the bacterial surface with morphological distortion. Atomic absorption spectrometric study corroborated this data, showing highest cadmium accumulation in the cell wall fraction of the bacteria. Additionally, the cell wall fraction showed synthesis of new proteins when grown under metal stress.     

Accumulation of Cadmium in and Its Effect on the Midgut Gland of Terrestrial Snail Helix pomatia L. from Urban Areas in Poland

The objectives of this study were (1) to determine cadmium (Cd) accumulation in the midgut gland of a land snail Helix pomatia L. inhabiting residential areas of the 14 largest cities in Poland, and (2) to examine whether the accumulated Cd exerted any toxic effects. The average accumulation of Cd in the midgut gland of snails, weighing 16–18 g, ranged from 7.00 to 87.3 µg/g dry weight (0.06–0.77 µmol/g) and differed significantly among animals from the various urban areas. This difference in Cd accumulation was not related to city population, but was associated with the topsoil Cd (R² = 0.868, p < 0.0001). The tissue Cd was not found to produce toxicity (histopathology, programmed cell death, lipofuscin formation or lipid peroxidation), probably due to the induction of sufficiently high quantities of metallothionein and glutathione, well-known protective molecules.     

类毒素-A对小鼠脑内即早基因表达的影响

目的 探讨即早基因在类毒素-A(ANTX-A)引起小鼠中枢神经毒性反应中的作用.方法 选取体重13～15g清洁级昆明种小鼠80只,在标准SPF级动物房内进行饲养.按体重将小鼠随机分为4组(高、中、低剂量组和对照组),每组20只,雌雄各半.高、中、低剂量组分别按200、50、12.5μg/kg剂量进行腹腔ANTX-A染毒;对照组腹腔注射生理盐水0.01ml/g.每天染毒1次,连续染毒1个月.采用RT-PCR法测定小鼠脑组织中c-fos、NGFI-A基因mRNA表达,采用免疫组织化学法测定小鼠脑组织中C-FOS、环腺苷酸反应元件结合蛋白(CREB)的表达.结果 雌性小鼠高、中剂量组和雄性小鼠高剂量组c-fos/β-actin条带面积比值高于对照组,差异均有统计学意义(P＜0.01).仅高剂量组雌、雄性小鼠脑组织C-FOS、CREB-1的表达高于对照组,差异均有统计学意义(P＜0.05).结论 c-fos和CREB基因在ANTX-A的中枢神经毒性中可能起调控作用.     

脉络丛对铅镉的屏护作用及其机理探讨

目的：研究急性染铅或镉后其在中枢神经系统的分布和GSH,巯基含量的变化。方法：分别给兔腹腔注射不同剂量的醋酸静脉注射不同剂量的氯化镉溶液,于4h和24h后处死动物,采集脑脊液,血液,侧脑室脉络丛,大脑皮质,肝脏和肾皮质样品,测定其中铅或镉含量以及GSH和巯基的含量。结果：发现脉络丛中的铅或镉含量明显增高,高于脑脊液,大脑皮质和血液,染铅后4h脉络丛中GSH升高,但染铅后24h明显降低,血液,大脑皮质,肝脏和肾皮质GSH含量在高剂量染铅后24h也明显降低;染铅后巯基含量的变化不明显。低剂量染镉后4 h GSH的变化不明显。24h降低,高剂量染镉后随时间延长GSH明显降低;低剂量染镉后24h,脉络丛,血液,大脑皮质和肾皮质巯基含量与对照组相比明显增高;高剂量染镉后24h,脉络丛和血液的巯基含量与对照组比明显降低,结论：侧脑室脉络丛对铅或镉有屏护作用,保持脑脊液成分的相对稳定,使脑组织免受来自血液的重金属的损伤,脉络丛的屏护作用机制与GSH和重金属的结合有关。     

Cadmium and Lead Accumulation in Three Endogeic Earthworm Species

The objective of this study was to assess the capability of earthworms from the same ecological group as heavy metal bioindicators. Three earthworm species from the endogeic group were studied: Aporrectodea caliginosa (Savigny, 1826), Perelia kaznakovi (Michaelsen, 1910) and Octolasion lacteum (Örley, 1885). Their accumulation of the heavy metals lead (Pb) and cadmium (Cd) were studied from three stations in Tehran province, Iran. O. lacteum was used to compare metal accumulations in two sites located next to a highway. A. caliginosa and P. kaznakovi were used at a third site located near the edge of a sewage system to compare metal accumulations between the two endogeic species in this area. At both locations, the concentrations of Cd and Pb in earthworms were higher than in the surrounding soil. The results of the study revealed that P. kaznakovi and A. caliginosa were better bioindicators for Pb, but O. lacteum was a better bioindicator for Cd. These earthworms can therefore be used as Cd and Pb bioindicators in environmental assessment.     

Cadmium Accumulation and Tolerance in Seven Ornamental Willow Genotypes

Cadmium (Cd) accumulation and tolerance in seven ornamental willow genotypes were investigated at different Cd levels (0, 5, 25, 50, and 100 µM) through hydroponic culture in a greenhouse. Severe phytotoxic symptoms in leaves and roots including leaf chlorosis and root browning were noticed when grown at ≥?50 µM Cd. All genotypes showed high tolerance to low Cd levels (5 µM and 25 µM Cd), in contrast to high Cd levels (i.e. 50 µM and 100 µM) that severely disturbed plant growth of all genotypes. Cadmium concentrations reached 165.0–1251.0 µg g^?1 DW in leaves, 22.9–331.2 µg g^?1 in stems among the genotypes at 5–25 µM Cd, and Cd mainly accumulated in the roots. Although willow tissues can accumulate relatively high Cd concentrations under high Cd levels (≥?50 µM), they are not suitable for phytoextraction of Cd due to poor growth.     

P27基因在口腔癌组织中的表达及其意义

目的探讨肿瘤抑制基因p27在口腔癌组织中的表达及其临床意义。方法应用免疫组织化学方法（SP法）检测p27基因在62例口腔癌组织和20例正常口腔黏膜组织中的表达。结果62例口腔癌组织中，p27的阳性表达率为38．7（24／62）；p27的阳性表达与口腔病灶大小、临床分期、细胞分化程度、转移及预后有密切关系（P〈0．01或P〈0．05）；与患者年龄无关（P〉0．05）。结论p27基因的表达与口腔癌的生长、浸润及淋巴结转移有关，其表达水平的高低可作为判断口腔癌预后的重要指标之一。     

Relationships Among Metallothionein, Cadmium Accumulation, and Cadmium Tolerance in Three Species of Fish

No abstract available.     

Accumulation and Depuration of Cd and its Effect on the Expressions of Metallothionein and Apoptotic Genes in Litopenaeus vannamei

We investigated cadmium (Cd) accumulation in muscles, gills and hepatopancreas of Litopenaeus vannamei following 48 h exposure to 5.25 mg/L, and depuration of Cd in these tissues on 1, 5 and 15 d post exposure. We also detected the expressions of metallothionein (MT), caspase-3 and p53 in hepatopancreas of shrimp exposed to 0, 5.25 and 10.5 mg/L Cd (the 24 h median lethal concentration, 24 h LC₅₀) at 0, 3, 12, 24 and 48 h. Cd accumulated with high concentration in hepatopancreas, and low concentration in muscles. Cd depurated fast in hepatopancreas and gills. MT expression increased in a time-dependent manner after Cd exposure. The p53 and caspase-3 increased at 12 and 24 h in 10.5 mg/L group. In conclusion, the accumulation and depuration of Cd in three tissues were tissues-specific. The changes of the expressions of MT, p53 and caspase-3, were stress response of L. vannamei under Cd exposure.

     

镉亚急性暴露对小鼠肝肾功能及甲基化水平的影响

[目的]初步探讨氯化镉(cadmium chloride,CdCl2)亚急性暴露(4周染毒)对小鼠肝肾功能、全基因组甲基化水平及去甲基化酶Tet1表达的影响. [方法]将48只SPF级KM小鼠(昆明小鼠,雌雄各半)随机分为4组:对照组(ddH2O)、CdCl2 17.5 mg/kg组、25 mg/kg组、35 mg/kg组.经口灌胃染毒(每天1次、每周5d),共染毒4周,CO2麻醉法处死动物.测定肝脏和肾脏的脏器系数、血液常规及血液生化检查、肝肾组织病理学检查、全基因组DNA甲基化水平及Tet1酶表达水平. [结果]35 mg/kg染毒组小鼠活动度及精神状态较差.小鼠体重在各染毒周期和染毒剂量组间差异均有统计学意义,且存在交互作用(P＜ 0.05).与对照组相比,雄性小鼠肝脏质量和肝脏脏器系数在25 mg/kg和35 mg/kg剂量组差异具有统计学意义(P＜0.05);血液常规检查结果显示,雌、雄性小鼠35 mg/kg染毒组血液白细胞(WBC)、血小板(PLT)、淋巴细胞(LYM)计数,均高于对照组(P＜0.05);雄性小鼠在各个染毒剂量组间,WBC、PLT、LYM、RBC计数差异有统计学意义(P＜0.05).此外,血生化实验结果显示,各剂量组雄性和雌性小鼠中肝功能的主要指标谷丙转氨酶(ALT)、碱性磷酸酶(ALP)差异有统计学意义(P＜0.05),肾功能的主要指标尿酸(UA)、血尿素氮(BUN)、肌酐(CR)差异均有统计学意义(P＜0.05).组织病理学分析发现25 mg/kg和35 mg/kg组雄性小鼠肝脏及肾脏呈现明显的病理性改变.Tet1 mRNA及其蛋白表达水平仅在雄性小鼠的肝脏、肾脏中表达的差异有统计学意义(P＜0.05).焦磷酸测序结果显示,雄性小鼠肝脏、肾脏甲基化水平表达差异有统计学意义(P＜0.05),且其与Tet1 mRNA表达呈负相关(r=-0.473,P＜0.05;r=-0.134,P＜0.05). [结论]CdCl2亚急性染毒可以诱导小鼠肝肾功能损伤,且对全基因组甲基化水平和去甲基化酶Tet1表达呈现出性别差异影响,雄性小鼠的肝肾组织Tet1表达参与调控全基因组DNA甲基化水平改变.