Air-quality biomonitoring: Assessment of genotoxicity of air pollution in the Province of Kayseri (Central Anatolia) by use of the lichen Pseudevernia furfuracea (L.) Zopf and amplified fragment-length polymorphism markers

Effect of elevated ozone on the antioxidant response, genomic stability, DNA methylation pattern and yield in three species of Abelmoschus having different ploidy levels

The majority of polyploids can withstand many stresses better than their monoploid counterparts; however, there is no proven mechanism that can fully explain the level of tolerance at the biochemical and molecular levels. Here, we make an effort to provide an explanation for this intriguing but perplexing issue using the antioxidant responses, genomic stability, DNA methylation pattern and yield in relation to ploidy level under the elevated level of ozone in Abelmoschus cytotypes. The outcome of this study inferred that the elevated ozone causes an increase in reactive oxygen species leading to enhanced lipid peroxidation, DNA damage and DNA de-methylation in all the Abelmoschus cytotypes. The monoploid cytotype of Abelmoschus, that is Abelmoschus moschatus L., experienced the highest oxidative stress under elevated O₃, resulting in maximum DNA damage and DNA de-methylation leading to the maximum reduction in yield. While the diploid (Abelmoschus esculentus L.) and triploid (Abelmoschus caillei A. Chev.) cytotypes of Abelmoschus with lower oxidative stress result in lesser DNA damage and DNA de-methylation which ultimately leads to lower yield reduction. The result of this experiment explicitly revealed that polyploidy confers better adaptability in the case of Abelmoschus cytotypes under ozone stress. This study can further be used as a base to understand the mechanism behind the ploidy-induced stress tolerance in other plants mediated by gene dosage effect.

Determination of airborne trace elements in an urban area using lichens as biomonitor

The amounts of elements emitted from industrial, domestic, and vehicle sources in Düzce through the analyses of lichens, which are bioindicators of air pollution, were determined in this research. Concentrations of Al, Fe, Cr, Mn, Co, Ni, Cu, Zn, As, V, Cd, Hg, and Pb in the lichens that were collected from 40 different points were analyzed using an inductively coupled plasma (ICP-MS) device. The highest concentration values were detected for Fe and Al, while the lowest concentration values were detected for Cd and Hg. Distribution maps of elements were created using geographic information systems. The distribution maps showed how the concentrations of elements for Düzce have changed across the city. According to our results, the elements sourced from traffic and combustion, such as Cr, Co, Ni, Cu, As, and V, have the highest concentrations in the city center near the traffic.

Nitric oxide ameliorates the damaging effects of oxidative stress induced by iron deficiency in cyanobacterium Anabaena 7120

In cyanobacterium Anabaena 7120, iron deficiency leads to oxidative stress with unavoidable consequences. Nitric oxide reduces pigment damage and supported the growth of Anabaena 7120 in iron-deficient conditions. Elevation in nitric oxide accumulation and reduced superoxide radical production justified the role of nitric oxide in alleviating oxidative stress in iron deficiency. Increased activities of antioxidative enzymes and higher levels of ROS scavengers (ascorbate, glutathione and thiol) in iron deficiency were also observed in the presence of nitric oxide. Nitric oxide also supported the membrane integrity of Anabaena cells and reduces protein and DNA damage caused by oxidative stress induced by iron deficiency. Results suggested that nitric oxide alleviates the damaging effects of oxidative stress induced by iron deficiency in cyanobacterium Anabaena 7120.

The comet assay in higher terrestrial plant model: Review and evolutionary trends

The comet assay is a sensitive technique for the measurement of DNA damage in individual cells. Although it has been primarily applied to animal cells, its adaptation to higher plant tissues significantly extends the utility of plants for environmental genotoxicity research. The present review focuses on 101 key publications and discusses protocols and evolutionary trends specific to higher plants. General consensus validates the use of the percentage of DNA found in the tail, the alkaline version of the test and root study. The comet protocol has proved its effectiveness and its adaptability for cultivated plant models. Its transposition in wild plants thus appears as a logical evolution. However, certain aspects of the protocol can be improved, namely through the systematic use of positive controls and increasing the number of nuclei read. These optimizations will permit the increase in the performance of this test, namely when interpreting mechanistic and physiological phenomena.

Cultivar specific variations in antioxidative defense system, genome and proteome of two tropical rice cultivars against ambient and elevated ozone

For the past few decades continuous increase in the levels of tropospheric ozone (O3) concentrations is posing to be a threat for agricultural productivity. Two high yielding tropical rice cultivars (Malviya dhan 36 and Shivani) were evaluated against different concentrations of O3 under field conditions. Experimental design included filtered chambers, non-filtered chambers having ambient O3 and 10 and 20ppb elevated O3 above the ambient. Study was conducted to assess differential response if any in induction of antioxidative defense system, genome stability, leaf proteome, yield and quality of the product in both the test cultivars. Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) were induced under ambient and elevated levels of O3. Native polyacrylamide gel electrophoresis (PAGE) of SOD, CAT and POD also displayed increased enzymatic activity along with associated alterations in specific isoforms. Ascorbic acid, thiols and phenolics were also stimulated at ambient and elevated O3. Structural alterations in DNA of rice plants due to O3 affecting its genome template stability (GTS) was examined using RAPD technique. 2-D PAGE revealed 25 differential spots in Malviya dhan 36 and 36 spots in Shivani after O3 treatment with reductions in RuBisCO subunits. Reductions in yield and change in the quality of grains were also noticed.

The determination of physiological and DNA changes in seedlings of maize (Zea mays L.) seeds exposed to the waters of the Gediz River and copper heavy metal stress

In this study, the effects of the heavy metal-polluted waters of the Gediz River, which flow into the Aegean Sea, and different concentrations of copper (Cu) solutions on maize (Zea mays L.) seedlings are investigated with physiological parameters and random amplified polymorphic DNA (RAPD) assay. Results displayed physiologically a significant difference in root and stem length between the control seedlings and the seedlings grown with the waters of the Gediz River. Also, the certain ascending concentrations of copper solution (80, 160, 320, 640, and 1280 ppm) caused a significant decrease in root and stem length of seedlings compared to the control seedlings. As a result of the waters of the Gediz River and copper solution treatment, the changes occurred in RAPD profiles of seedlings observed as variations like increment and/or loss of bands compared with the control seedlings. And these changes were reflected as a decrease in genomic template stability (GTS, changes in RAPD profile) derived by genotoxicity. RAPD band profiles and GTS values showed consistent results with physiological parameter. In conclusion, the study revealed the environmental risk and negative effect of waters of the Gediz River on maize seedlings and the suitability of RAPD assay for the detection of environmental toxicology.

Evaluating the genotoxicity of urban PM2.5 using PCR-based methods in human lung cells and the Salmonella TA98 reverse test

A number of compounds found in particulate matter with an aerodynamic diameter <2.5 (PM2.5) can interact with DNA either directly or after enzymatic transformation to induce DNA modifications. These particulate matter (PM)-induced alterations in DNA may be associated with increased frequencies of pollution-associated diseases, such as lung cancer. In the present study, we applied different methods to assess the mutagenicity and genotoxicity of monthly PM2.5 organic extracts collected over a full year. We used the Salmonella assay, exposed cultured human embryonic lung fibroblasts and applied extracellular lactate dehydrogenase (LDH) and 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt (XTT) assays to assess the cytotoxicity of PM2.5 on the cells. We assessed both the expression levels of a number of DNA repair genes (using qRT-qPCR) and the genetic profile of the treated cells compared to the control. The expression levels of XRCC1 and APE1, which are involved in the first steps of base excision repair, as well as ERCC1, XPA and XPF, which encode nucleotide excision repair subunits, were analysed. The monthly mean of the PM2.5 collected was 35.16 ± 22.06 μg/m(3). The mutagenicity of PM2.5 to TA98 was 46 ± 50 net revertants/m(3), while the mutagenicity to TA98 + S9 was 17 ± 19 net revertants/m(3). The mean IC50 values were 2.741 ± 1.414 and 3.219 ± 2.764 m(3) of equivalent air in the XTT and LDH assays, respectively. A marked and significant increase in APE1 expression levels was observed in the exposed cells. This effect was also significantly correlated with mutagenicity (p < 0.01). No induced AFLP fragment profile alterations were detected. The proposed approach seems to be useful for integrated evaluation and for highlighting the mechanisms inducing DNA damage.