Risk assessment of cadmium-contaminated soil on plant DNA damage using RAPD and physiological indices

The protection role of heat shock protein 70 (HSP-70) in the testes of cadmium-exposed rats

Cadmium (Cd) is an environmental carcinogenic pollutant known to inactivate several proteins involved in DNA repair systems while at the same time creating an oxidative stress that can result in additional DNA lesions. The testis and the lung are the target organs for cadmium carcinogenesis. Increased production of oxidants in vivo can cause damage to intracellular macromolecules such as DNA, proteins and lipids, which in turn lead to oxidative injury. So, this investigation aimed to evaluate the protective role of L-Carnitine through up regulation of HSPs against DNA damage induced by cadmium chloride. The current study was carried out on forty adult male rats, each with average weight 220-250g., were divided into 4 equal groups. 1(st) group was received saline solution (0.5 ml/100 g body weight) and kept as control. 2(nd) group was received 500mg / kg body weight L-Carnitine intraperitoneally (IP). 3(rd) group was administered 1.2 mg cadmium chloride IP. 4(th) group was received both cadmium chloride and L-Carnitine simultaneously. The comet assay parameters showed significantly increased HSP70 and DNA damage in testis cells after 10 and 56 days in the third group. Meanwhile, HSP70 showed significantly decreased levels after 10 days and 56 days in the fourth group after L-Carnitine treatment simultaneously with cadmium chloride. The results of the present study demonstrate a damaging effect of cadmium chloride on DNA of the testis cells (with low stress response). This damaging effect increases the synthesis of HSP70 that upregulated by L-Carnitine treatment and showed ameliorative effect of the cells for recovery.

Assessment of the genotoxicity of heavy metals in Phaseolus vulgaris L. as a model plant system by Random Amplified Polymorphic DNA (RAPD) analysis

Impact assessments of environmental pollutants are important in eco-genotoxicology. A random amplified polymorphic DNA (RAPD) technique was used to detect genotoxicity-induced DNA damage in Phaseolus vulgaris L. from heavy metals at two different concentrations. The results from six 10-base pair (bp) random RAPD primers with 60-70% GC content used, showed a total of 295 RAPD fragments of 700-4000 bp in molecular size in the seedlings of untreated and treated samples, of which only 163 fragments were polymorphic. Polymorphisms became evident as the disappearance and/or appearance of DNA fragments in treated samples compared to the control. A dendrogram constructed using the Numerical Taxonomy and Multivariate Analysis System (NTSYSps), showed that the control group merged with groups treated with CuSO(4)·5H(2)O (150 mg L(-1)) and MnSO(4)·H(2)O (150 mg L(-1)) in a separate cluster. These groups were linked with all of the other samples treated with metals at concentrations of 150 mg L(-1) and CuSO(4)·5H(2)O and Cd(NO(3))(2) at concentrations of 350 mg L(-1). Finally, the samples treated with metals at concentrations of 350 mg L(-1) together with NiSO(4) at the concentration of 150 mg L(-1), clustered separately. The DNA polymorphism detected by RAPD analysis offered a useful biomarker assay for the detection of toxic chemicals genotoxicity in plant model systems.

Freshwater toxic cyanobacteria induced DNA damage in apple (Malus pumila), rape (Brassica napus) and rice (Oryza sativa)

Cyanobacteria in freshwater ecosystems can present a harmful effect on growth and development of plants through irrigation with contaminated water. In this study, the effects of microcystins (MCs)-containing cyanobacteria extract (CE) on DNA damage of apple, rape and rice were investigated to explore the phytotoxic mechanism of MCs through DNA fragmentation and RAPD analysis. Determination of DNA fragmentation by fluorescent dye DAPI showed that significant DNA damage was observed in rice seedlings after exposure to CE while DNA fragmentation in rape seedlings and apple cultures did not differ significantly between treatment and control groups. Qualitative characterization of genomic DNA fragmentation by agarose gel electrophoresis supported the quantitative determination using DAPI. The main changes in RAPD profiles of rape seedlings following exposure of lower doses of CE were variation in band intensity for the primers F03 and S01, while higher doses of CE caused loss of normal bands and appearance of new bands except band intensity changes. The data presented here demonstrate that DNA damage in plants occurs following exposure of microcystins, and the polymorphic RAPDs may be used as an investigation tool for environmental toxicology and as a useful biomarker for the detection of genotoxic effects of microcystins on plants.

Fixed-bed column study for Cu2+ removal from solution using expanding rice husk

This paper deals with removal of copper ions from solution by raw rice husk (RRH) and expanding rice husk (ERH). Different column design parameters like bed depth, flow rate and initial copper concentration were investigated. It was found that the equilibrium uptake (q(eq(exp))) of the ERH and RRH increased with increase in initial copper concentration but decreased with increase in flow rate and bed depth, respectively. The higher adsorption capacity and longer breakthrough time were observed for ERH in comparison with RRH, under the same conditions. Compared to coconut-shell activated carbon (C-AC), ERH was also found more effective in removing Cu(2+). 0.01 mol L(-1) HCl solution was used for desorption of column which was prior to absorb copper ion, and 0.01 mol L(-1) NaOH solution was used for re-activation. Column regeneration and reuse studies were conducted for adsorption-desorption cycle.

Supplemental ultraviolet-B and ozone: impact on antioxidants, proteome and genome of linseed (Linum usitatissimum L. cv. Padmini)

The present investigation used Linum usitatissimum L. cv. Padmini (linseed), under field conditions in open-top chambers, to evaluate the interactive effects of supplemental ultraviolet-B (sUV-B; ambient +7.2 kJ · m(-2) · d(-1)) and ozone (O(3); ambient +10 ppb). Treatment of plants with sUV-B and O(3) , individually or in combination, caused several changes in enzymatic and non-enzymatic components of the antioxidant defence system. Photo-oxidative damage caused by sUV-B and O(3) , included lipid peroxidation, changed protein profiles and caused DNA strand breakage. One-dimensional gel electrophoresis revealed that proteins of 222.24 and 50.5 kDa are specific and appear after sUV-B and O(3) exposure, and could be used as indicator proteins. Effects of sUV-B and O(3) given separately are more detrimental as compared to combined treatment. Mutational and structural alterations in linseed DNA after these stresses were also examined using RAPD with ten different primers. The study concluded that both stresses, i.e. sUV-B and O(3) , are phytotoxic, causing significant changes in metabolites, antioxidants, the leaf proteome and the genome of linseed, but their interactive effect was always less than additive.

Cadmium-induced genotoxicity in zebrafish at environmentally relevant doses

Genotoxic effects of cadmium on zebra fish Danio rerio have been assessed by random amplified polymorphic DNA and real time PCR, followed by a comparison of the melting temperature patterns between each amplification reaction. Fish were exposed to two concentrations of cadmium chloride dissolved in the medium (1.9+/-0.6 microg Cdl(-1), C(1); 9.6+/-2.9 microg Cdl(-1), C(2)) for 21 days. A discriminative RAPD probe, OPB11, was first selected producing differential band patterns between control and metal-exposed genomic DNAs. RAPD-PCR showed an increase in the relative hybridization efficiency of OPB11 on the genomic DNAs coming from fish exposed to both Cd concentrations as compared to the control condition. In addition, the RAPD-PCR melting temperature patterns showed that with the OPB11 probe, the frequency of PCR products whose fusion temperature belongs to the [86-87 degrees C] interval decreased with Cd contamination, whereas an increase of frequency for the [78-80 degrees C] and [85-86 degrees C] intervals was correlated with Cd exposure.

Progress in the remediation of hazardous heavy metal-polluted soils by natural zeolite

Hazardous heavy metal pollution of soils is an increasingly urgent problem all over the world. The zeolite as a natural amendment has been studied extensively for the remediation of hazardous heavy metal-polluted soils with recycling. But its theory and application dose are not fully clear. This paper reviews the related aspects of theory and application progress for the remediation of hazardous heavy metal-polluted soils by natural zeolite, with special emphasis on single/co-remediation. Based on the comments on hazardous heavy metal behavior characteristics in leaching and rhizosphere and remediation with zeolite for heavy metal-polluted soils, it indicated that the research of rhizosphere should be strengthened. Theory of remediation with natural zeolite could make breakthroughs due to the investigation on synthetic zeolite. Co-remediation with natural zeolite may be applied and studied with more prospect and sustainable recycling.