AFLP analysis as biomarker of exposure to organic and inorganic genotoxic substances in plants

Offsetting pb induced oxidative stress in Vicia faba plants by foliar spray of chitosan through adjustment of morpho-biochemical and molecular indices

In the course of their life, plants face a multitude of environmental anomaly that affects their growth and production. In recent decades, lead (Pb) gained an increasing attention as it is among the most significant contaminants in the environment. Therefore, in this study the effects of Pb concentrations (0, 50 and 100 ppm) on Vicia faba plants and attempts to alleviate this stress using chitosan (Chs; 0 and 0.1%) were performed. The results validated that with increasing Pb concentrations, a decline in growth, pigments and protein contents was observed. In the same time, a significant upsurge in the stress markers, both malondialdehyde (MDA) and H2O2, was observed under Pb stress. Nonetheless, foliar spraying with Chs improves the faba bean growth, pigment fractions, protein, carbohydrates, reduces MDA and H2O2 contents and decreases Pb concentrations under Pb stress. Pb mitigation effects by Chs are probably related with the activity of antioxidant enzymes, phenylalanine ammonia lyase (PAL) and proline. The application of Chs enhanced the activities of peroxidase, catalase and PAL by 25.77, 17.71 and 20.07%, respectively at 100 ppm Pb compared to their control. Plant genomic material exhibits significant molecular polymorphism, with an average polymorphism of 91.66% across all primers. To assess the genetic distance created among treatments, the dendrogram was constructed and the results of the similarity index ranged from 0.75 to 0.95, indicating genetic divergence. Our research offers a thorough comprehension of the role of Chs in lessening the oxidative stress, which will encourage the use of Chs in agricultural plant protection.

1-Methyl-1H-1,2,4-triazole as the main marker of 1,1-dimethylhydrazine exposure in plants

With their wide application in chemical industry, human health and environmental toxic effects of hydrazines arise extensive concerns. Although hydrazine exposure is known to lead to inhibition of seed germination and seedling growth in plants, there are few reports about the mechanism of oxidation or transformation ways of hydrazines in plant tissue. In this research, garden cress (Lepidium sativum L.) and zucchini (Cucurbita pepo L.) were used as model plant objects to study 1,1-dimethylhydrazine exposure in vitro using the GC-MS system. The seed germination and plant growth experiments were carried out in Petri dishes using an aqueous media. Among the detected 1,1-dimethylhydrazine transformation products in plant tissues, 1-methyl-1H-1,2,4-triazole had the highest intensity and reproducibility. In our research, 1-methyl-1H-1,2,4-triazole formed at all contaminant concentrations in an extremely short period. This preliminary study determined 1,1-dimethylhydrazine environment contamination by detecting 1-methyl-1H-1,2,4-triazole in combination with other transformation products.

Improving plant-based genotoxicity bioassay through AFLP technique for trace metal-contaminated water: insights from Myriophyllum aquaticum (Vell.) Verdc. and Cd

In this work, we evaluated whether the species Myriophyllum aquaticum (Vell.) Verdc. can be a promising material for devising reliable eco-toxicological tests for Cd-contaminated waters. Plants of M. aquaticum were exposed to Cd, using different concentrations (1 mg L-1, 2.5 mg L-1, 5 mg L-1, and 10 mg L-1; experiment 1) and exposure times (2.5 mg L-1 for 3 days, 7 days, 14 days, and 21 days; experiment 2). Plant growth and Cd accumulation were monitored during the treatment period, and Cd genotoxicity was assessed by analyzing Cd-induced changes in the AFLP fingerprinting profiles using famEcoRI(TAC)/MseI(ATG) and hexEcoRI(ACG)/MseI(ATG) pairs of primers. Root and shoot growth was reduced already at the lowest Cd concentration used (about 20% reduction for roots and 60% for shoots at 1 mg L-1; experiment 1) and after 7 days (about 50% reduction for roots and 70% for shoots; experiment 2). The primer combinations produced 154 and 191 polymorphic loci for experiments 1 and 2, respectively. Mean genetic diversity (He) reduction among the treatment groups was observed starting from 2.5 mg L-1 (He 0.211 treated vs 0.236 control; experiment 1) and after 3 days (He 0.169 treated vs 0.261 control; experiment 2), indicating that results obtained from AFLP profiles did not match with plant growth measurements. Therefore, our results showed that M. aquaticum proved to be a suitable model system for the investigation of Cd genotoxicity through AFLP fingerprinting profile, whereas the more classic eco-toxicological tests based only on biometric parameters could not correctly estimate the risk associated with undetected Cd genotoxicity.

Chromium-Induced Reactive Oxygen Species Accumulation by Altering the Enzymatic Antioxidant System and Associated Cytotoxic, Genotoxic, Ultrastructural, and Photosynthetic Changes in Plants

Chromium (Cr) is one of the top seven toxic heavy metals, being ranked 21st among the abundantly found metals in the earth’s crust. A huge amount of Cr releases from various industries and Cr mines, which is accumulating in the agricultural land, is significantly reducing the crop development, growth, and yield. Chromium mediates phytotoxicity either by direct interaction with different plant parts and metabolic pathways or it generates internal stress by inducing the accumulation of reactive oxygen species (ROS). Thus, the role of Cr-induced ROS in the phytotoxicity is very important. In the current study, we reviewed the most recent publications regarding Cr-induced ROS, Cr-induced alteration in the enzymatic antioxidant system, Cr-induced lipid peroxidation and cell membrane damage, Cr-induced DNA damage and genotoxicity, Cr-induced ultrastructural changes in cell and subcellular level, and Cr-induced alterations in photosynthesis and photosynthetic apparatus. Taken together, we conclude that Cr-induced ROS and the suppression of the enzymatic antioxidant system actually mediate Cr-induced cytotoxic, genotoxic, ultrastructural, and photosynthetic changes in plants.

The potential of Mikania micrantha (Chinese creeper) to hyperaccumulate heavy metals in soil contaminated by electronic waste

The objective of this study is to investigate the contributions of Mikania micrantha (chinese creeper) to remediate heavy metal pollutants present in an e-waste-contaminated soil. Different proportions of e-waste soil (0%, 25%, 50%, 75%, and 100% w/w) planted with Cynodon dactylon together with the test species were prepared for testing relative seed germination (RSG), relative root growth (RRG), and germination index (GI) tests. A significant higher value of GI (77.8%) was found in M. micrantha than that of the other species when planting in 100% e-waste-contaminated soil. A significant correlation (< 0.05) was found between heavy metal concentration and germination assays in M. micrantha. A significant decrease in heavy metal concentration of the polluted soil after the experiment indicated that biomolecule development studies to determine the aggregate benefit of M. micrantha for phytoremediation remain to be studied in future.

Comparative analysis of cadmium-induced stress responses by the aromatic and non-aromatic rice genotypes of West Bengal

Constant exposure of the living ecosystems to heavy metals, like cadmium (Cd), induces a detectable change at the biochemical and genetic level. Repeated application of phosphate fertilizers in paddy fields, leads to increase in Cd content of soil. Cd being highly mobile is transported to shoot and grain, thereby entering into the food chain of animal system. In the present study, treatment of 7-day old rice seedlings with 10 μM cadmium chloride resulted in Cd toxicity across the seven non-aromatic and six aromatic rice cultivars and landraces used for the study. Free proline and malondialdehyde content of treated samples were higher in comparison to the untreated samples, which indicated Cd induced tissue damage in plants. Photosynthetic pigment content of treated samples was also found to be much lower in comparison to the untreated samples, which is probably due to peroxidation of membrane, leading to compromised and lower photosynthetic efficiency of treated plants. At the genetic level, Randomly Amplified Polymorphic DNA assay was found to efficiently detect the genetic polymorphisms (caused by alterations in DNA bases) induced by Cd. Production of unique polymorphic bands in Cd-treated plants helps in assessment of the degree of damage Cd imparts on the plant system. Cluster analysis was performed and the rice genotypes were grouped into five distinct clusters, with IR64 and Tulsibhog in two distinct groups. Based on the variability in responses, the 13 rice genotypes were grouped into sensitive and tolerant ones.

AFLP Approach Reveals Variability in Phragmites australis: Implications for Its Die-Back and Evidence for Genotoxic Effects

Phragmites australis is a subcosmopolitan species typical of wetlands being studied in Europe for its disappearance from natural stands, a phenomenon called reed die-back syndrome (RDBS). Although it is conjectured that low genetic variability contributes to RDBS, this aspect remains neglected to this day. Using a molecular fingerprinting approach and a sequence analysis of the trnT-trnL/rbcL-psaI regions of cpDNA, this study aimed to compare the genetic structure of stable vs. RDBS-affected P. australis stands from five wetlands of central Italy. Beforehand, in order to characterize the health condition of reed populations, the occurrence of the main macromorphological descriptors for RDBS was considered on 40 reed stands. Soil samples were also collected to examine the total content of heavy metals. The current study analyzed cpDNA in 19 samples and AFLP profiles in 381 samples to investigate the genetic structure of Phragmites populations. Based on the multinomial-Dirichlet model, an analysis of candidate loci under selective pressure was also performed. The relationships among AFLP data, RDBS descriptors and chemicals were evaluated with the use of Linear Mixed Models. The analysis of the cpDNA shows the occurrence of the haplotypes M (the most widespread), and K here recorded for the first time in Italy. Three new haplotypes were also described. The DNA fingerprinting analysis has produced a total of 322 loci (98% polymorphic) and shows the medium-to-high amount of genetic diversity. The significant genetic differentiation among wetlands (Fst = 0.337) suggests either low gene flow or small effective population size. Moreover, the low amount of outlier loci (only 5; l.5% of the total), seems to indicate the scarce occurrence of selective pressure upon the reed's genome. Genetic diversity increased in relationship to the decrease in diameter and of flowering buds of the reed, two of the trends associated with the die-back. The current study rejects the hypothesis that genetic diversity massively contributed to RDBS. Moreover, significant relationships between genetic diversity and the total concentration of some heavy metals (Cr, Cu, and Zn) were highlighted, indicating possible genotoxic effects on P. australis. The current study represents a fact-finding background useful for the conservation of common reed.

Genotoxic effect of Pb and Cd on in vitro cultures of Sphagnum palustre: An evaluation by ISSR markers

In the present work, the genotoxic effect of cadmium and lead supplied in a laboratory trial, was investigated for the first time in the moss Sphagnum palustre, by ISSR molecular markers. A total of 169 reproducible bands were obtained with 12 primers, ten of which gave polymorphisms (i.e., appearance/disappearance of bands), indicating a clear genotoxic effect induced by the metals. Both metals induced a decrease of the genome template stability in a dose dependent manner. At concentration >10^-5 Cd also induced a general toxic effect in S. palustre, leading to chlorophyll degradation and moss death. Moreover, we followed the fate of supplied heavy metals into the moss tissue by SEM-EDX to see if they entered the cells. SEM-EDX observations on moss cultures treated with equimolar concentrations of the two metals showed that most Pb precipitated in form of particles on moss surface, while Cd did not aggregate in particles and was not found on moss surface. In light of these findings, we concluded that probably Pb induced a genotoxic effect at lower intracellular concentrations than Cd.

Chromium speciation, bioavailability, uptake, toxicity and detoxification in soil-plant system: A review

Chromium (Cr) is a potentially toxic heavy metal which does not have any essential metabolic function in plants. Various past and recent studies highlight the biogeochemistry of Cr in the soil-plant system. This review traces a plausible link among Cr speciation, bioavailability, phytouptake, phytotoxicity and detoxification based on available data, especially published from 2010 to 2016. Chromium occurs in different chemical forms (primarily as chromite (Cr(III)) and chromate (Cr(VI)) in soil which vary markedly in term of their biogeochemical behavior. Chromium behavior in soil, its soil-plant transfer and accumulation in different plant parts vary with its chemical form, plant type and soil physico-chemical properties. Soil microbial community plays a key role in governing Cr speciation and behavior in soil. Chromium does not have any specific transporter for its uptake by plants and it primarily enters the plants through specific and non-specific channels of essential ions. Chromium accumulates predominantly in plant root tissues with very limited translocation to shoots. Inside plants, Cr provokes numerous deleterious effects to several physiological, morphological, and biochemical processes. Chromium induces phytotoxicity by interfering plant growth, nutrient uptake and photosynthesis, inducing enhanced generation of reactive oxygen species, causing lipid peroxidation and altering the antioxidant activities. Plants tolerate Cr toxicity via various defense mechanisms such as complexation by organic ligands, compartmentation into the vacuole, and scavenging ROS via antioxidative enzymes. Consumption of Cr-contaminated-food can cause human health risks by inducing severe clinical conditions. Therefore, there is a dire need to monitor biogeochemical behavior of Cr in soil-plant system.

Tradescantia as a biomonitor for pesticide genotoxicity evaluation of iprodione, carbaryl, dimethoate and 4,4'-DDE

There is a current tendency to develop and apply environmentally friendly techniques that meet the requirements of green analytical chemistry as an alternative to conventional analytical methods. For toxicity evaluation, these alternatives may be found in bioassays such as Tradescantia. This technique, developed in the 1980s, is highly sensitive to evaluate environmental mutagens, simple and cheap. In this paper, the sensibility of both the Tradescantia micronucleus bioassay (Trad-MCN) and the Tradescantia stamen hair bioassay (Trad-SH) were studied for carbaryl, dimethoate and iprodione, common agricultural and domestic pesticides that are currently used in Chile, which have never been tested with such bioassays. Biomonitor exposures were performed by capillary absorption for each individual pesticide over a wide range of concentrations, from maximum residue limits (trace levels) up to the application dose in agricultural fields. In addition, the organochloride 4,4'-DDE was included but only in the concentration range from 0.01mgL^-1 to 1mgL^-1, mimicking residue concentrations since it is not a commercial product but, rather, the main breakdown product of the persistent organochloride pesticide 4,4-DDT, whose use was discontinued in Chile in the 1980s. The Trad-MCN bioassay revealed a significant increase in micronucleus frequency at the early tetrads of meiotic pollen mother cells of the biomonitor Tradescantia pallida var. purpurea, induced by 4,4'-DDE (for 1mgL^-1), dimethoate (for 40mgL^-1, 200mgL^-1, 400mg/L^-1) and carbaryl (for 889mgL^-1). Iprodione did not generate any significant change at the tested concentration. Meanwhile, the Trad-SH bioassay was carried out by analysis of the phenotype variations of the stamen hair cells of the Tradescantia clone KU-20 for the same pesticides and doses. This bioassay was not sufficiently sensitive for toxicity evaluation of most of the pesticides tested, with exception of dimethoate in low doses (2 and 5mg/L^-1).

Evaluation of genotoxic variations in plant model systems in a case of metal stressors

This study was designed to assess the effects of long term, high metal exposition (cadmium, lead, copper, nickel and zinc) on DNA damage in four plant model systems [Taraxacum officinale (Asteraceae), Matricaria recutita L. (Asteraceae), Robinia pseudoacacia L. (Fabaceae), and Urtica dioica (Urticaceae)]. DNA stability was investigated by a Random Amplified Polymorphic DNA (RAPD) technique. Agarose-gel electrophoresis revealed total of 37 bands with different molecular weights ranging from 1250 to 5000 bp. It generated distinctive polymorphism value of 72.97% (27 bands) total in four plant species investigated. The dendrogram constructed using NTSYSpc programme showed that there is grouping in separate clusters of the same plant model collected from two different areas (metal-exposed and control samples). The study concluded that the long term metal-exposing periods had genotoxic stress on macromolecules of plant model systems investigated and biomarkers used should be augmented for reliable estimates of genotoxicity after exposure of plants to metal stressors.

Determination of genotoxic effects of fipronil in Vicia faba using random amplified polymorphic DNA analysis

This study was undertaken to appreciate genotoxic potential of fipronil herbicides in the roots of Vicia faba seedlings. Fipronil was clearly dose dependent on root growth inhibitors, total soluble protein, and random amplified polymorphic DNA (RAPD) assays. Increase in concentration of fipronil resulted in decreased amount of root length and increased level of protein. For the RAPD analyses, 15 RAPD primers were found to produce unique polymorphic band patterns and were subsequently used to produce a total of 110 bands of 45–1250 bp. Each primer generated 4–11 RAPD bands across 15 primers. The changes occurring in RAPD profiles following fipronil treatment included variation becoming evident as disappearance and/or appearance of DNA bands compared with the normal seedlings. These results indicated that genomic template stability was significantly affected at the above fipronil concentration. This study further confirmed that the RAPD assays are useful in determining potential genotoxicity of fipronil.

Phytotoxic and genotoxic effects of silver nanoparticles exposure on germinating wheat seedlings

We investigated the effects of 1 and 10 mg L(-1) AgNPs on germinating Triticum aestivum L. seedlings. The exposure to 10 mg L(-1) AgNPs adversely affected the seedling growth and induced morphological modifications in root tip cells. TEM analysis suggests that the observed effects were due primarily to the release of Ag ions from AgNPs. To gain an increased understanding of the molecular response to AgNP exposure, we analyzed the genomic and proteomic changes induced by AgNPs in wheat seedlings. At the DNA level, we applied the AFLP technique and we found that both treatments did not induce any significant DNA polymorphisms. 2DE profiling of roots and shoots treated with 10 mg L(-1) of AgNPs revealed an altered expression of several proteins mainly involved in primary metabolism and cell defense.

Detection of tannery effluents induced DNA damage in mung bean by use of random amplified polymorphic DNA markers

Common effluent treatment plant (CETP) is employed for treatment of tannery effluent. However, the performance of CETP for reducing the genotoxic substances from the raw effluent is not known. In this study, phytotoxic and genotoxic effects of tannery effluents were investigated in mung bean (Vigna radiata (L.) Wilczek). For this purpose, untreated and treated tannery effluents were collected from CETP Unnao (UP), India. Seeds of mung bean were grown in soil irrigated with various concentrations of tannery effluents (0, 25, 50, 75, and 100%) for 15 days. Inhibition of seed germination was 90% by 25% untreated effluent and 75% treated effluent, compared to the control. Plant growth was inhibited by 51% and 41% when irrigated with untreated and treated effluents at 25% concentration. RAPD technique was used to evaluate the genotoxic effect of tannery effluents (untreated and treated) irrigation on the mung bean. The RAPD profiles obtained showed that both untreated and treated were having genotoxic effects on mung bean plants. This was discernible with appearance/disappearance of bands in the treatments compared with control plants. A total of 87 RAPD bands were obtained using eight primers and 42 (48%) of these showed polymorphism. Irrigating plants with untreated effluent caused 12 new bands to appear and 18 to disappear. Treated effluent caused 8 new bands and the loss of 15 bands. The genetic distances shown on the dendrogram revealed that control plants and those irrigated with treated effluent were clustered in one group (joined at distance of 0.28), whereas those irrigated with untreated effluent were separated in another cluster at larger distance (joined at distance of 0.42). This indicates that treated effluent is less genotoxic than the untreated. Nei's genetic similarity indices calculated between the treatments and the control plants showed that the control and the plants irrigated with treated tannery effluent had a similarity index of 0.75, the control and plants irrigated with untreated 0.65, and between the treatments 0.68. We conclude that both untreated and treated effluents contain genotoxic substances that caused DNA damage to mung beans. CETP Unnao removes some, but not all, genotoxic substances from tannery effluent. Consequently, use of both untreated and treated wastewater for irrigation poses health hazard to human and the environment.

Exposure to Cr(VI) induces organ dependent MSI in two loci related with photophosphorylation and with glutamine metabolism

Chromium (Cr), as a mutagenic agent in plants, has received less attention than other metal pollutants. To understand if Cr induces microsatellite instability (MSI), Pisum sativum seedlings were exposed for 28 days to different concentrations of Cr(VI) up to 2000mgL(-1), and the genetic instability of ten microsatellites (SSRs) was analyzed. In plants exposed to Cr(VI) up to 1000mg L(-1), MSI was never observed. However, roots exposed to 2000mgL(-1) displayed MSI in two of the loci analyzed, corresponding to a mutation rate of 8.3%. SSR2 (inserted in the locus for plastid photosystem I 24kDa light harvesting protein) and SSR6 (inserted in the locus for P. sativum glutamine synthetase) from Cr(VI)-treated roots presented alleles with, respectively, less 6bp and more 3bp than the corresponding controls. This report demonstrates that: (a) SSRs technique is sensitive to detect Cr-induced mutagenicity in plants, being Cr-induced-MSI dose and organ dependent (roots are more sensitive); (b) two Cr-sensitive loci are related with thylakoid photophosphorylation and with glutamine synthetase, respectively; (c) despite MSI is induced by Cr(VI), it only occurs in plants exposed to concentrations higher than 1000mgL(-1) (values rarely found in real scenarios). Considering these data, we also discuss the known functional changes induced by Cr(VI) in photosynthesis and in glutamine synthetase activity.

Chromium as an Environmental Pollutant: Insights on Induced Plant Toxicity

In the past decades the increased use of chromium (Cr) in several anthropogenic activities and consequent contamination of soil and water have become an increasing concern. Cr exists in several oxidation states but the most stable and common forms are Cr(0), Cr(III) and Cr(VI) species. Cr toxicity in plants depends on its valence state. Cr(VI) as being highly mobile is toxic, while Cr(III) as less mobile is less toxic. Cr is taken up by plants through carriers of essential ions such as sulphate. Cr uptake, translocation, and accumulation depend on its speciation, which also conditions its toxicity to plants. Symptoms of Cr toxicity in plants are diverse and include decrease of seed germination, reduction of growth, decrease of yield, inhibition of enzymatic activities, impairment of photosynthesis, nutrient and oxidative imbalances, and mutagenesis.

Molecular determination of genotoxic effects of cobalt and nickel on maize (Zea mays L.) by RAPD and protein analyses

Assessment of DNA damages stemming from toxic chemicals is an important issue in terms of genotoxicology. In this study, maize (Zea mays L.) seedlings were used for screening the genotoxic effects of cobalt (Co) and nickel (Ni) treatments at various concentrations (5 mM, 10 mM, 20 mM and 40 mM). For this purpose, randomly amplified polymorphic DNA (RAPD) technique was applied to genomic DNA extracted from metal-exposed and unexposed plant materials. Besides, changes in total protein contents were screened by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. For RAPD analysis, 16 RAPD primers were found to produce unique polymorphic band profiles on different concentrations of Co-/Ni-treated maize seedlings. Increased polymorphism resulting from the appearance of new bands or disappearance of normal bands was observed with increasing concentration of Co and Ni treatments. Genomic template stability, a qualitative measurement of changes in RAPD patterns of genomic DNA, decreased with increasing metal concentration. In SDS-PAGE analysis, it was observed that the total soluble protein content decreased by Co treatment, while it increased by Ni treatment. The results obtained from this study revealed that RAPD profiles and total soluble protein levels can be applied to detect genotoxicity, and these analyses can offer useful biomarker assays for the evaluation of genotoxic effects on Co- and Ni-polluted plants.

Cr(VI) induces DNA damage, cell cycle arrest and polyploidization: a flow cytometric and comet assay study in Pisum sativum

Chromium(VI) is recognized as the most toxic valency of Cr, but its genotoxicity and cytostaticity in plants is still poorly studied. In order to analyze Cr(VI) cyto- and gentotoxicity, Pisum sativum L. plants were grown in soil and watered with solutions with different concentrations of Cr up to 2000 mg/L. After 28 days of exposure, leaves showed no significant variations in either cell cycle dynamics or ploidy level. As for DNA damage, flow cytometric (FCM) histograms showed significant differences in full peak coefficient of variation (FPCV) values, suggesting clastogenicity. This is paralleled by the Comet assay results, showing an increase in DNA damage for 1000 and 2000 mg/L. In roots, exposure to 2000 mg/L resulted in cell cycle arrest at the G(2)/M checkpoint. It was also verified that under the same conditions 40% of the individuals analyzed suffered polyploidization having both 2C and 4C levels. DNA damage analysis by the Comet assay and FCM revealed dose-dependent increases in DNA damage and FPCV. Through this, we have unequivocally demonstrated for the first time in plants that Cr exposure can result in DNA damage, cell cycle arrest, and polyploidization. Moreover, we critically compare the validity of the Comet assay and FCM in evaluating cytogenetic toxicity tests in plants and demonstrate that the data provided by both techniques complement each other and present high correlation levels. In conclusion, the data presented provides new insight on Cr effects in plants in general and supports the use of the parameters tested in this study as reliable endpoints for this metal toxicity in plants.

Assessment of air pollution genotoxicity by RAPD in Evernia prunastri L. Ach. from around iron-steel factory in Karabük, Turkey

Lichens are widely used in biomonitoring studies of air pollution, either as bioindicators of air quality or as bioaccumulators of atmospheric deposition. Over the past decade, several molecular techniques have been developed to provide information on diversity, genotoxicology, genetic relationships, etc. The heavy metal contents of Evernia prunastri samples were determined by atomic absorption spectrometry. The Random Amplified Polymorphic DNA Polymerase Chain Reaction (RAPD-PCR) method was used to describe the pattern of DNA band variation in the samples influenced by the environmental pollution. The study was designed to describe the level of pollution in an area contaminated with smoke and waste from an iron-steel factory, and to reveal the level of potential genotoxic agents around this source of pollution. The study also examined the suitability of the lichen samples for the detection of genotoxicity.

Effects of sodium dodecylbenzene sulfonate and sodium dodecyl sulfate on the Mytilus galloprovincialis biomarker system

The effects of in vivo exposure of Mytilus galloprovincialis to two anionic surfactants (SDBS and SDS) on the molecular biomarker system were studied. After continuous exposure for 72 days, activities/levels of GST, GPx and GSH were significantly higher than in corresponding control groups following exposure to 3.000 mg/L SDS and SDBS. Activities of SOD and CAT were significantly inhibited by experimental SDBS (except CAT in 0.100mg/L group), but not by SDS. Statistical analysis of enzyme activities/levels suggested that there were significant positive relationships between GST and GPx, and negative relationships were found between GSH and CAT, GSH and SOD. Amplified fragment length polymorphism (AFLP) results showed that a greater genotoxic effect was observed for SDBS than for SDS. Based on the above results, the biomarker system of mussels can be affected by the two anionic surfactants (>or=3.000 mg/L); it was more easily affected by SDBS than by SDS.

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

Impact assessment of contaminants in soil is an important issue in environmental quality study and remediation of contaminated land. A random amplified polymorphic DNA (RAPD) 'fingerprinting' technique was exhibited to detect genotoxin-induced DNA damage of plants from heavy metal contaminated soil. This study compared the effects occurring at molecular and population levels in barley seedlings exposed to cadmium (Cd) contamination in soil. Results indicate that reduction of root growth and increase of total soluble protein level in the root tips of barley seedlings occurred with the ascending Cd concentrations. For the RAPD analyses, nine 10-base pair (bp) random RAPD primers (decamers) with 60-70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 129 RAPD fragments of 144-2639 base pair in molecular size in the root tips of control seedlings. Results produced from nine primers indicate that the changes occurring in RAPD profiles of the root tips following Cd treatment included alterations in band intensity as well as gain or loss of bands compared with the control seedlings. New amplified fragments at molecular size from approximately 154 to 2245 bp appeared almost for 10, 20 and 40 mg L(-1) Cd with 9 primers (one-four new polymerase chain reaction, (PCR) products), and the number of missing bands enhanced with the increasing Cd concentration for nine primers. These results suggest that genomic template stability reflecting changes in RAPD profiles were significantly affected and it compared favourably with the traditional indices such as growth and soluble protein level at the above Cd concentrations. The DNA polymorphisms detected by RAPD can be applied as a suitable biomarker assay for detection of the genotoxic effects of Cd stress in soil on plants. As a tool in risk assessment the RAPD assay can be used in characterisation of Cd hazard in soil.

Impact assessment of cadmium contamination on rice (Oryza sativa L.) seedlings at molecular and population levels using multiple biomarkers

Assessment of environmental contamination on ecology (plant) at molecular and population levels is important in risk quantification and remediation study. Random amplified polymorphic DNA (RAPD) assay and related other fingerprinting techniques have been employed to detect the genotoxin-induced DNA damage and mutations. This research compared the effects occurring at molecular and population levels in rice seedlings exposed to cadmium (Cd) concentrations of 15-60 mg l(-1) for 8 days with quartz sand culture. Inhibition of root growth and increase of total soluble protein content in root tips of rice seedlings were observed with the increase of Cd concentration. For the RAPD analyses, 12 RAPD primers of 50-70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 180 bands of 179-3056 bp in molecular size in the control root tips of rice seedlings. Results produced by these RAPD primers indicate that changes in RAPD profiles of root tips after Cd treatment include modifications in band intensity and gain or loss of bands by comparison with control. The effect of changes was dose-dependent. Genomic template stability compares favourably with the traditional indices such as root growth and soluble protein content. The DNA polymorphisms detected by RAPD analysis can be applied as a suitable biomarker assay for the detection of genotoxic effects of Cd contamination on plants.

Multiple biomarkers response in maize (Zea mays L.) during exposure to copper

Biomarkers in higher plants played an important role to estimate exposure effects of pollutants in soil ecosystem and have received increasing attention in recent years. The qualitative and quantitative modifications arising in amplified fragment length polymorphism (AFLP) profiles as a measure of DNA effects were compared with a number of parameters, namely, the root length, total soluble protein content in root tips, chlorophylls content and shoot size to select the most sensitive biomarker responding to copper stress in the range of 0-600 mg/kg. The changes occurring in AFLP profiles of root tips following Cu treatment included loss of normal bands and appearance of new bands and variation in band intensity in comparison to that of the normal seedlings. A reduction in root length was observed at the 200 mg/kg of copper, which was accompanied with a decrease in total soluble protein content. According to their sensitivity to the copper toxicity, the above indicator rank in the following order: AFLP profiles > total soluble protein content > root length > chlorophylls content > shoot. We concluded that the AFLP offered a useful alternative biomarker assay for the detection of genotoxic effects of environmental pollutants.

DNA changes in barley (Hordeum vulgare) seedlings induced by cadmium pollution using RAPD analysis

In recent years, several plant species have been used as bioindicators, and several tests have been developed to evaluate the toxicity of environmental contaminants on vegetal organisms. In this study, barley (Hordeum vulgare L) seedling was used as bioindicator of cadmium (Cd) pollution in the range of 30-120 mgl(-1). Inhibition of root growth and reduction of total soluble protein content in root tips of barley seedlings were observed with the increase of Cd concentrations. The changes occurring in random amplified polymorphic DNA (RAPD) profiles of root tips following Cd treatment included variation in band intensity, loss of normal bands and appearance of new bands compared with the normal seedlings. Additionally, we found that the effect of changes was dose-dependent. These results indicated that genomic template stability (a qualitative measure reflecting changes in RAPD profiles) was significantly affected at the above Cd concentration. Thus, DNA polymorphisms detected by RAPD analysis could be used as an investigation tool for environmental toxicology and as a useful biomarker assay for the detection of genotoxic effects of Cd pollution on plants.