Cadmium-induced Changes Research Articles

The Protective Effect of the Supplementation with an Extract from Aronia melanocarpa L. Berries against Cadmium-Induced Changes of Chosen Biomarkers of Neurotoxicity in the Brain-A Study in a Rat Model of Current Lifetime Human Exposure to This Toxic Heavy Metal.

Since even low-level environmental exposure to cadmium (Cd) can lead to numerous unfavourable health outcomes, including damage to the nervous system, it is important to recognize the risk of health damage by this xenobiotic, the mechanisms of its toxic influence, and to find an effective protective strategy. This study aimed to evaluate, in a female Wistar rat model of current human environmental exposure to Cd (1 and 5 mg/kg of diet for 3-24 months), if the low-to-moderate treatment with this element can harm the brain and whether the supplementation with a 0.1% Aronia melanocarpa L. (Michx.) Elliott berries (chokeberries) extract (AE) can protect against this effect. The exposure to Cd modified the values of various biomarkers of neurotoxicity, including enzymes (acetylcholinesterase (AChE), sodium-potassium adenosine triphosphatase (Na+/K+-ATPase), phospholipase A2 (PLA2), and nitric oxide synthase 1 (NOS1)) and non-enzymatic proteins (calmodulin (CAM), nuclear factor erythroid 2-related factor 2 (Nrf2), and Kelch-like ECH-associated protein 1 (KEAP1)) crucial for the functioning of the nervous system, as well as the concentrations of calcium (Ca) and magnesium (Mg) and some metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in the brain tissue. The co-administration of AE, partially or entirely, protected from most of the Cd-induced changes alleviating its neurotoxic influence. In conclusion, even low-level chronic exposure to Cd may adversely affect the nervous system, whereas the supplementation with A. melanocarpa berries products during the treatment seems a protective strategy.

Cadmium-Induced Changes in the Accumulation of Sugars and the PsGolS Transcript in Pisum sativum L.

Cadmium (Cd) is a key stress factor that affects plant development. To examine the influence of Cd stress, we analysed the tissue localisation of polysaccharides (Periodic Acid Schiff reaction), qualitative and quantitative changes in soluble carbohydrates (High-Resolution Gas Chromatography), and the expression of the galactinol synthase (PsGolS) and raffinose synthase (PsRS) genes in 4-week-old Pisum sativum L. ‘Pegaz’. The plants were treated with 10, 50, 100, and 200 µM CdSO4 for one week and analysed on the 1st, 7th, and 28th days after Cd application. Pea as an excluder plant accumulated Cd mainly in the roots. Cd induced starch grain storage in the stems and the accumulation of soluble carbohydrates in roots and shoots after 28 days of Cd treatment. In controls, soluble carbohydrate levels decreased during the plant growth. In addition, Cd increased galactinol and raffinose levels, indicating their important role in response to Cd stress in peas. Moreover, the analysis confirmed that the expression of PsGolS was induced by Cd. Overall, the results of the distribution of carbohydrates in pea plants, together with the inhibition of seed production by Cd, indicate that plants tend to allocate energy to stress response mechanisms rather than to reproductive processes.

Insights into strigolactone (GR24) mediated regulation of cadmium-induced changes and ROS metabolism in Artemisia annua

Agricultural soil contamination and subsequently crops still require alternative solutions to reduce associated environmental risks. The effects of strigolactones (SLs) in alleviating cadmium (Cd) phytotoxicity in Artemisia annua plants were investigated during this study. Strigolactones play a vital role during plant growth and development due to their complex interplay during a plethora of biochemical processes. However, information on the potential of SLs to elicit abiotic stress signaling and trigger physiological modifications in plants is limited. In order to decipher the same, A. annua plants were exposed to different concentrations of Cd (20 and 40 mg kg-1), with or without the supplementation of exogenous SL (GR24, a SL analogue) at 4 µM concentration. Under Cd stress, excess Cd accumulation resulted in reduced growth, physio-biochemical traits, and artemisinin content. However, the follow-up treatment of GR24 maintained a steady state equilibrium between reactive oxygen species and antioxidant enzymes, improved chlorophyll fluorescence parameters such as Fv/Fm, ФPSII, and ETR for improved photosynthesis, enhanced chlorophyll content, maintained chloroplast ultrastructure, improved the glandular trichome (GT) attributes and artemisinin production in A. annua. Moreover, it also resulted in improved membrane stability, reduced Cd accumulation, and regulated the behaviour of stomatal apertures for better stomatal conductance under Cd stress. The results of our study suggest that GR24 could be highly effective in alleviating Cd-induced damages in A. annua. It acts via the modulation of the antioxidant enzyme system for redox homeostasis, protection of the chloroplasts and pigments for improved photosynthetic performance, and improved GT attributes for enhanced artemisinin production in A. annua.

Effects of Naringenin on Cadmium-Induced Changes in Blood Physiological and Biochemical Indices and Kidney Damage Among Rats

Effects of Naringenin on Cadmium-Induced Changes in Blood Physiological and Biochemical Indices and Kidney Damage Among Rats

Role of Clove oil in Cadmium-Induced changes in tumor necrosis factor (TNFα) and Lymphatic tissues of wistar rats

BackgroundThymus and bone marrows are vital and primary organs of the lymphoid system and important targets for toxins and chemical agents. ObjectiveThe aim was to study the role of clove oil on Cadmium-induced changes in TNFα and lymphatic tissues of adult Wistar rats. MethodologyTwenty-five rats were assigned into five groups of five rats each. Group 1 (Control) was allowed food and water only; group 2 was given 20 mg/kg of Cadmium chloride (CdCl2); group 3 received 20 mg/kg of CdCl2 with 10 mg/kg of Clove oil (CLO), group 4 received 20 mg/kg of CdCl with 20 mg/kg of CLO while group 5 received 20 mg/kg of CdCl and 20 mg/kg of DMSO. After the experiment, blood, bone marrow, and the thymus were harvested, processed, and analyzed. ResultsThere was a significant decrease in PCV, MCV, and MCH in group 2 compared to the control (p≤0.05). PCV, MCV, and MCH significantly increased in groups 3 and 4. The result of TNFα significantly increased in treated groups 3, 4, and 5 compared to group 2 (p≤0.05). The results showed normal architectural features of the bone marrow and thymus in control, while group 2 showed several structural distortions with many improvements in groups 3, 4, and 5. ConclusionThe study showed that clove oil ameliorated the toxicity associated with CdCl2 by normalizing hematological and immunological parameters.

Preventive effects of Tephrosia lupinifolia DC. on haematological alterations induced by cadmium in Sprague-Dawley rats

Introduction: Cadmium is known to be one of the most noxious environmental and industrial pollutant. Cigarette smoke and food products are the major sources of cadmium exposure in non-occupationally exposed people. Tephrosia lupinifolia DC. (Fabaceae) is commonly known as Fish poison. It has usage in treatment of diarrhea, stomachache, urinary disorders, asthma and rheumatism. Objectives: This investigation was aimed to examine the protective potentials of Tephrosia lupinifolia DC. against cadmium-induced changes in haematological parameters of Sprague-Dawley rats. Methodology: In present study, male rats (n=30) were taken and equally divided into five groups. Rats were orally administrated with relevant doses of methanolic extract of Tephrosia lupinifolia (25, 50 mg/kg bw) for 7 days and then CdCl2 (4 mg/kg) was intravenously injected to produce acute toxicity. At the end of experiment, rats were dissected to collect blood for haematological analysis. Results: Cadmium treatment caused significant decline of RBCs (P=0.002), PCV and Hb concentration (P=0.0001) as compared to control. It also elevates the WBC count (P<0.001), concentration of lymphocytes, neutrophil percentages, MCV, MCHC and MCH values (P=0.05). The changes induced by cadmium in different haematological parameters were improved in the rats treated with Tephrosia lupinifolia. Conclusion: The outcomes of this study recommended that methanolic extract of Tephrosia lupinifolia (TLME) ameliorates the harmful effects of CdCl2 on blood parameters which can be credited to the presence of different phytochemical constituents in it.

Effects of exogenous glycinebetaine on cadmium-induced changes in photosynthetic performance, antioxidative metabolism and ATPase in cucumber seedlings

A hydroponic experiment was carried out to study the ameliorative effects of exogenous glycinebetaine (GB) upon cadmium (Cd) toxicity in cucumber seedlings. The results indicated that 50 μmol/L Cd stress decreased soil plant analysis development (SPAD) value, plant height, root length, seedling biomass, activities of ascorbate peroxidase (APX) and ATPase in leaves, stems and roots; however, increased peroxidase (POD) and superoxide dismutase (SOD) activities in all tissues, catalase (CAT) activities in stems/roots. Moreover, Cd stress also elevated leaf/root malondialdehyde (MDA), proline, phenols and flavonoid content in all cucumber tissues over the control. The supplementation of GB (Cd + GB) prominently alleviated Cd-induced growth inhibition and oxidative stress, increased SPAD value and stem ATPase, and improved photosynthetic performance compared with Cd treatment alone. Furthermore, external GB diminished leaf/root MDA accumulation and decreased leaf/root proline contents as well as phenols and flavonoid contents in all tissues. Meanwhile, exogenous GB counteracted Cd-induced alterations of certain antioxidant enzymes. For example, it brought all tissue POD and SOD activities and stem/root CAT activities down towards the control level and significantly increased APX activities, especially in leaves and stems. These data suggested the principal protective mechanism for the exogenous GB against Cd toxicity in cucumber seedlings is closely related to improved photosynthesis, diminished Cd-induced proline and MDA accumulation, enhanced ATPase as well as modulation of antioxidant enzymes.

Time Course of Age-Linked Changes in Photosynthetic Efficiency of Spirodela polyrhiza Exposed to Cadmium.

Short-term assessment of adverse effects is essential for populations exposed to higher risk of environmental pollution. This study presents the time course of physiological and morphological changes attributed to cadmium, emphasizing age-linked differences in the susceptibility of photosynthetic apparatus of Spirodela polyrhiza fronds exposed to different cadmium concentrations. A four-frond colony represented by mother, daughter, and granddaughter plants was exposed to cadmium concentrations for 6, 24, and 72 h to establish its effect on different generations of the great duckweed. The duration of cadmium exposure accounted for the most variation in chlorophyll content as the most influential variable, and after 72 h, frond responsiveness was a function of cadmium concentration. Carotenoid contents behaved slightly differently in fronds of different ages, with the oldest mother frond exhibiting accelerated senescence. Chlorophyll fluorescence measurements showed that cadmium affects different photosynthetic electron transport segments relative to the frond's chloroplast structure level. Photosynthesis of mother fronds exposed to low cadmium and daughter fronds exposed to high cadmium was determined by the functionality of primary electron acceptance at the PSII level. Mother plants exposed to higher cadmium concentrations were characterized by closed and inactive reaction centers, dissipated energy outflux, and inhibited photosynthesis. Young fronds exposed to low and high cadmium concentrations were characterized by increased non-reducing reaction centers and thermal phase reduction, with activated dissipative mechanisms at high cadmium concentrations. Cadmium-induced changes in the ultrastructure of chloroplasts were visible after 6 h of exposure to lowest concentrations, with gradual degradation of the thylakoid system as the fronds aged. Younger fronds responded to cadmium more dynamically through molecular, physiological, and anatomical changes and tolerated a more reduced electron transport chain under given conditions than older fronds.

Neuroprotective activity of Ipomoea cairica leaf extract against cadmium chloride-induced biochemical changes in the brain of male Wistar rats

BackgroundExposure to cadmium is implicated in the etiology of some neurodegenerative diseases. Compounds isolated from Ipomoea cairica extract are neuroprotective. However, there is no reported neuroprotective activity of the crude extract of I. cairica (ICE). We investigated the neuroprotective activity of I. cairica extract against cadmium-induced biochemical changes in the brain of male Wistar rats. Thirty-six animals were divided into four groups of 9 animals per group: group I (Control); group II (3.5 mg/kg CdCl2); group III (100 mg/kg ICE + CdCl2); and group IV (250 mg/kg ICE + CdCl2). Animals were pretreated with 100 and 250 mg/kg ICE before co-administration with cadmium chloride.ResultsCdCl2 treatment caused a significant increase in acetylcholineesterase activity, lipid peroxidation, beta-amyloid aggregation, caspase 3 and 9, p53, and glutamate concentration. In addition, CdCl2 caused a significant decrease in catalase activity, superoxide dismutase, glutathione-S-transferase, Na+/K+ ATPase, and glutamate dehydrogenase. ICE was able to reduce the neuronal damaging effect of CdCl2 by acting as an antioxidant, antiapoptotic, anticholinesterase, and antiexcitotoxicity.ConclusionsOur findings show that Ipomoea cairica leaf can be developed and included in the natural product in the prevention of neurodegenerative diseases.

Genome-Wide Analysis of Cadmium-Induced, Germline Mutations in a Long-Term Daphnia pulex Mutation-Accumulation Experiment.

Background:Germline mutations provide the raw material for all evolutionary processes and contribute to the occurrence of spontaneous human diseases and disorders. Yet despite the daily interaction of humans and other organisms with an increasing number of chemicals that are potentially mutagenic, precise measurements of chemically induced changes to the genome-wide rate and spectrum of germline mutation are lacking.Objectives:A large-scale Daphnia pulex mutation-accumulation experiment was propagated in the presence and absence of an environmentally relevant cadmium concentration to quantify the influence of cadmium on germline mutation rates and spectra.Results:Cadmium exposure dramatically changed the genome-wide rates and regional spectra of germline mutations. In comparison with those in control conditions, Daphnia exposed to cadmium had a higher overall mutation rates and a lower overall mutation rate. Daphnia exposed to cadmium had a higher intergenic mutation rate and a lower exonic mutation rate. The higher intergenic mutation rate under cadmium exposure was the result of an elevated intergenic rate, whereas the lower exon mutation rate in cadmium was the result of a complete loss of exonic mutations—mutations that are known to be enriched at 5-hydroxymethylcytosine. We experimentally show that cadmium exposure significantly reduced 5-hydroxymethylcytosine levels.Discussion:These results provide evidence that cadmium changes regional mutation rates and can influence regional rates by interfering with an epigenetic process in the Daphnia pulex germline. We further suggest these observed cadmium-induced changes to the Daphnia germline mutation rate may be explained by cadmium’s inhibition of zinc-containing domains. The cadmium-induced changes to germline mutation rates and spectra we report provide a comprehensive view of the mutagenic perils of cadmium and give insight into its potential impact on human population health. https://doi.org/10.1289/EHP8932

Effect of quercetin and curcumin in rats sub-acutely exposed to cadmium chloride: haemato-biochemical changes, oxidative stress parameters and histopathological changes in intestine, liver and kidney of rats

Quercetin is a flavonoid mostly found in fruits and vegetables. Curcumin is the main natural polyphenol found in the rhizome of Curcuma longa and in others Curcuma spp.. Individually, quercetin and curcumin had shown to have various pharmacological properties. The increasing level of cadmium in the environment is alarming as cadmium affects the antioxidant defense system with ability to persist in the body for long time. The bioaccumulation of cadmium is well-known, which is dangerous for the health of human and animals after continuous exposure to it. The present experiment was carried out to evaluate the ameliorating effect of quercetin (50 mg/kg daily orally for 28 days) and curcumin (100 mg/kg daily orally for 28 days) alone and in combination of both against cadmium-induced (100 ppm in water for 28 days) alterations in biochemical markers and histological changes in intestine, liver and kidney of rats. Body weight gain in rats of toxicity group during the 4th week of study period was significantly affected by the cadmium. Cadmium exposure significantly increased the levels of AST, ALT, ALP, bilirubin and glucose in serum along with higher level of MDA in intestine, liver and kidney of rats. The administration of quercetin and curcumin in combination as compared to individual treatment along with cadmium exposure had shown significantly lower levels of above parameters. Various histological changes were noticed in intestine, liver and kidney of rats following exposure to cadmium which were improved in rats treated with individual or combined treatment of quercetin and curcumin. Quercetin alone had shown the ameliorating effect against cadmium-induced alteration in kidney of rats. While, combination of quercetin and curcumin has been found to protect the intestine and liver from cadmium-induced damage following sub-acute exposure in rats. However, further study is needed to explore the mechanism of protective effect of the quercetin and curcumin against cadmiuminduced changes in intestine, liver and kidney.

Cadmium-induced changes in composition and co-metabolism of glycerolipids species in wheat root: Glycerolipidomic and transcriptomic approach

Lipids are the structural constituents of cell membranes and play crucial roles in plant adaptation to abiotic stresses. The aim of this study was to use glycerolipidomic and transcriptomic to analyze the changes in lipids metabolism induced by cadmium (Cd) exposure in wheat. The results indicated that Cd stress did not decrease the concentrations of monogalactosyldiacyglycerol (MGDG), phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and phosphatidic acid at 6 h, but decreased digalactosyldoacylglycerol (DGDG), MGDG, PC, phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS) and LPC concentrations in wheat root at 24 h. Although the concentrations of highly abundant glycerolipids PC and PE were decreased, the ratios of PC/PE increased thus contributing to wheat adaptation to Cd stress. Cd did not reduce the extent of total lipid unsaturation due to the unchanged concentrations of high abundance species of C36:4, C34:2, C34:3 and C36:6 at 6 h, indicative of their roles in resisting Cd stress. The correlation analysis revealed the glycerolipids species experiencing co-metabolism under Cd stress, which is driven by the activated expression of genes related to glycerolipid metabolism, desaturation and oxylipin synthesis. This study gives insights into the changes of glycerolipids induced by Cd and the roles in wheat adaptation to Cd stress.

Partial protective effects of melatonin on cadmium-induced changes in hematological characteristics in rats

ABSTRACT We investigated the effects of melatonin (Mlt) on hematological characteristics to determine the percentage of alpha-naphthyl acetate esterase (ANAE) positive lymphocytes in rats chronically exposed to cadmium (Cd). We used four groups of male rats: control (C), melatonin (Mlt), cadmium (Cd) and Cd + Mlt (CdMlt). Blood samples were obtained to assess the erythrocytes (RBC), leukocytes (WBC), platelets (PLT), hemoglobin (HGB), hematocrit (HCT), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV) as well as alpha-naphthyl acetate esterase (ANAE) positive lymphocytes. We found that the number of WBC increased in the Cd group compared to the other three experimental groups. Low MCV and MCHC values caused by Cd were ameliorated by Mlt treatment in the CdMlt group. We found no significant change in the RBC, HGB, MCH, PLT and HCT values among the experimental groups. Mlt treatment also increased the percentage of ANAE positive lymphocytes. Mlt partially protects some hematological characteristics in cases of chronic Cd toxicity.

The Toxic Effect of Environmental Cadmium on Visceral Adipose Tissue

Cadmium is an environmental toxin strongly associated with the development of cancer, kidney and liver disease, and bone demineralization. Whether cadmium causes obesity in humans remains a subject of controversy in the literature. An NHANES study that examined the effect of various toxic metals on central obesity demonstrated a decrease in the BMI of subjects exposed to cadmium. The purpose of this study is to examine the effect of cadmium on visceral adipose tissue (VAT), the potential for chelation to reverse cadmium‐induced changes, and to investigate the mechanism by which these changes occur. VAT is the subset of adipose tissue most heavily implicated in the pathogenesis of obesity, insulin resistance, and metabolic syndrome. ICR mice were placed into one of three groups: control, cadmium followed by washout, and cadmium followed by chelation. Mice in the two experimental groups were treated with 100ppm CdCl2 drinking water for 8 weeks followed by either 8 weeks of washout or 8 weeks of chelation with DMSA. Digital analysis of H&E images was performed using ImageJ and morphometric parameters of approximately 400 adipocytes per group were obtained. A 14.6% reduction in adipocyte size was observed in the group treated with cadmium followed by washout relative to the control group (p < 0.0001). In the group that underwent chelation after cadmium exposure, there was an increase in adipocyte size relative to the cadmium‐washout group (p<0.002). Additionally, animals in the cadmium‐washout group had a 5% reduction in body weight relative to control (p<0.0001). There was no significant difference in weight between the control group and the cadmium‐chelation group. In conclusion, the mouse model we have developed demonstrates that chronic low dose cadmium exposure causes weight loss and that chelation has the potential to reverse this change. Although the effect of cadmium on body weight remains controversial, this mouse model may serve to clarify this relationship and address the mechanism of cadmium’s action.Support or Funding InformationNIEHS Grant # P30 ES027792‐02

Modulation of Cadmium Tolerance in Rice: Insight into Vanillic Acid-Induced Upregulation of Antioxidant Defense and Glyoxalase Systems.

Cadmium (Cd) is a toxic heavy metal that enters the human food chain from the soil via plants. Increased Cd uptake and translocation in plants alters metabolism andreduces crop production. Maintaining crop yield therefore requires both soil remediation andenhanced plant tolerance to Cd. In this study, we investigated the effects of vanillic acid (VA) on Cd accumulation and Cd stress tolerance in rice (Oryza sativa L. cv. BRRI dhan54). Thirteen-day-old rice seedlings treated with CdCl2 (1.0 and 2.0 mM) for 72 h showed reduced growth, biomass accumulation, and water and photosynthetic pigment contents, as well as increased signs of oxidative stress (elevated levels of malondialdehyde, hydrogen peroxide, methylglyoxal, and lipoxygenase) and downregulated antioxidant and glyoxalase systems. Cadmium-induced changes in leaf relative turgidity, photosynthetic pigment content, ascorbate pool size, and glutathione content were suppressed by VA under both mild and severe Cd toxicity stress. The supplementation of VA under Cd stress conditions also increased antioxidant and glyoxylase enzyme activity. Vanillic acid also increased phytochelatin content and the biological accumulation factor, biological accumulation co-efficient, and Cd translocation factor. Vanillic acid, therefore appears to enhance Cd stress tolerance by increasing metal chelation and sequestration, by upregulating antioxidant defense and glyoxalase systems, and by facilitating nutrient homeostasis.

The cadmium-induced changes in the polar and neutral lipid compositions suggest the involvement of triacylglycerol in the defense response in maize.

Cadmium (Cd) is a heavy metal ion leading to morphological and physiological disorders in plants; a specific toxicity target is the membrane lipids. The total lipids were separated by thin-layer chromatography, and the fatty acid composition of the total (TLs), polar lipids (PLs) and triacylglycerol (TAG)-a neutral lipid-was analyzed in maize seedlings in hydroponics and treated by various Cd concentrations (0-200µM Cd). The TLs and PLs significantly decreased in roots after Cd treatment, suggesting the onset of lipid peroxidation mediated by oxygen free radicals, that induce alterations of the membrane structure and function. There were also increases in the TAG from 28.2 to 36.9% of TLs, and the TAG/PLs ratio varied from 0.59 to 0.84, in control and after exposure to 200µM Cd, respectively. The TAG plays potent roles in membrane turnover serving as energy and carbon resources for the biosynthesis of membrane lipids, to preserve membrane structure and function, and therefore cell homeostasis in response to Cd. In shoots, a significant increase in the levels of C16:0, C18:1, and C18:2, while a decrease in that of C18:3was observed, suggesting inhibition of desaturases enzymes. These lead to impairment of the chloroplast membrane. The total lipid content did not change under Cd stress. The PLs, however, decreased from 22.4 to 13.6mgg-1 DW; their percent to TLs varied from 86.6 to 52.5%, in control, and after Cd treatment, respectively. In conclusion, the accumulation of TAG may represent a defense strategy by which maize seedlings can withstand the effects of Cd toxicity, leading to reduced oxidative stress.

Antioxidative system response of pedunculate oak (Quercus robur L.) seedlings to Cd exposure

The use of pedunculate oak (Quercus robur L.), along with other tree species, for the afforestation of heavy metal contaminated lands is an attractive prospect. Little, however, is known of Q. robur tolerance and its antioxidative system response to heavy metal exposure. The main objective of the study was to determine the cadmium-induced changes in antioxidative system of pedunculate oak in an attempt to identify molecular mechanisms underlying Cd tolerance. This may be of great importance in respect of using Q. robur for phytoremediation purposes. As the response of the antioxidative system to heavy metal contamination can vary within species, the research was conducted on oak seedlings from two different regions of origin. Differences in antioxidative system response of seedlings derived from tested regions of origin were noticed both at the transcript and enzyme activity levels. The obtained results indicate that ascorbate peroxidase (APX; EC 1.11.1.11) and superoxide dismutase (SOD; EC 1.15.1.1) play a first barrier role in oak seedlings response to the oxidative stress caused by Cd exposure. Catalase (CAT; EC 1.11.1.6) is involved in reducing the negative effects of prolonged Cd treatment.

Nitric oxide affects cadmium-induced changes in the lichen Ramalina farinacea

Metabolic responses of epiphytic lichen Ramalina farinacea to cadmium (Cd) and/or nitric oxide (NO) scavenger (cPTIO) were studied. Accumulation of Cd and other metallic nutrients was not affected by cPTIO while total and absorbed amounts differed. Cd-induced NO formation was suppressed by cPTIO but ROS signal was synergistically enhanced, confirming that NO is essential to keep ROS under control. This excessive ROS generation could be a reason for depleted amount of all fatty acids, including SFAs, MUFAs and PUFAs. Total content of fatty acids reached 3.89 mg/g DW in control with linoleic (40%), palmitic (24%), oleic (12.8%) and stearic (8%) acids as major compounds: interestingly, shift in relative ratio of saturated (from 40 to 35% of total FAs) versus polyunsaturated fatty acids (from 42 to 48% of total FAs) was observed. Glutathione was suppressed by all treatments but Krebs acids were almost unaffected by cPTIO, indicating no regulatory role of NO in their accumulation. On the contrary, Cd-induced elevation in NO signal was related to increase in ascorbate and proline content while cPTIO suppressed it, indicating a tight relation between NO and these metabolites. Data are compared also with algae and vascular plants to show similarities between various life lineages.

Protective effect of melatonin on cadmium-induced changes in some maturation and reproductive parameters of female Prussian carp (Carassius gibelio B.)

The aim of this study was to determine whether melatonin (Mel), which is a known antioxidant and free radical scavenger, could perform the role of a preventive agent against the toxic effects of cadmium (Cd2+) on mortality, fish growth, gonadosomatic index (GSI), luteinizing hormone (LH) secretion, the response to hormonal stimulation of spawning, and also tissue accumulation of Cd in Prussian carp females. These females received melatonin implants and were exposed to 0.4 or 4.0 mg/L of Cd (as CdCl2·2.5H2O) over either a 5- or 3-month period, followed by further 2 months of purification in clear water. Negative changes caused by exposure to cadmium in the water were as follows: higher fish mortality, lower body weight, increased accumulation of cadmium in the brain and ovary, lowered GSI, impaired spontaneous LH secretion during exposure, and impaired LH secretion during stimulation of spawning. All of these effects were observed in the group of fish exposed to 0.4 and/or 4.0 mg Cd/L but did not occur or were less pronounced in the groups exposed to cadmium in the presence of melatonin released from the implants. During depuration, in the group of fish which had been exposed to the highest Cd concentration, we observed a significant improvement in fish survival rate, body growth, inhibition of further cadmium accumulation in tissues, and gradual return of spontaneous LH secretion as well as normalization of the GSI value to the control group levels. In conclusion, these findings indicate that melatonin can be a preventive agent for some toxic effects on fish reproduction induced by environmental cadmium contamination.

Cadmium-induced changes in vacuolar aspects of Arabidopsis thaliana

We have examined the changes due to Cd treatment in the vacuolar form in root tip cortical cells in Arabidopsis thaliana employing a transformant with GFP fused to a tonoplast protein. A Cd-induced enhancement in complexity with general expansion of vacuolar system within 24 h was evident. The changes in the vacuolar form were dependent on the applied Cd concentrations. Concomitantly, as revealed through dithizone staining, Cd accumulated in the seedling roots exhibiting abundance of Cd-dithizone complexes in root tip, root hairs and vasculature. To get insight into the involvement of SNARE protein-mediated vesicle fusion in Cd detoxification, the magnitude of Cd toxicity in a couple of knock out mutants of the vacuolar Qa-SNARE protein VAM3/SYP22 was compared with that in the wild type. The Cd toxicity appeared to be comparable in the mutants and the wild type. In order to analyze the Cd effects at cellular level, we treated the Arabidopsis suspension-cultured cells with Cd. Cd, however, did not induce a change in the vacuolar form in suspension-cultured cells although Cd measured with ICP-MS was obviously taken up into the cell. The V-ATPase activity in the microsomal fractions from vacuoles isolated from A. thaliana suspension cultured cells remained unaffected by Cd. Changes in the levels of certain metabolites of Cd-treated cells were also not so distinct except for those of glutathione. The significance of findings is discussed.