Application of molecular markers to detect DNA damage caused by environmental pollutants in lichen species.

Pseudevernia furfuracea L. (Zopf), Peltigera praetextata (Flörke ex Sommerf.) Zopf, Lobaria pulmonaria (L.) Hoffm., and Usnea longissima Ach. lichen species were used as bioindicators to assess the genotoxicity of air pollutants. In the present study, we examined significant environmetal pollutants and investigate how changes may lead to damage in DNA structure using RAPD markers. In the study area (Erzurum, Turkey), poor-quality lignite, which generates a large amount of sulfur dioxide, nitrogen oxides, and particle matter, is used for domestic heating, and vehicles also contribute to air pollution. Control lichen samples were collected far from large urban and industrial settlements and transplanted to four polluted sites for 4, 8, or 12 months. The total soluble protein content of the examined four lichen species did not significantly change with exposure time (P < 0.05). The four lichen samples exposed to the pollutants for 8 months had the highest ratio of DNA changes. The ratio of band differences in P. praetextata was higher than that in the other three lichen species, possibly because it has broad leaves that accumulated more pollutants. The average incidences of polymorphism were 64.14, 54.58, 65.76, and 43.06% for P. furfuracea, P. praetextata, L. pulmonaria, and U. longissima, respectively. The genomic template stability (GTS) significantly decreased following exposure to pollutants. GTS ratios revealed that the highest value (98.36%) belonged to U. longissima samples from Site 1 (10 m) after 4 months of exposure, and the lowest values belonged to P. praetextata (73.58%) from Site 3 (100 m) after 8 months of exposure. Based on our findings, we recommend the use of P. praetextata as an indicator of genotoxicity.

Evaluation of genotoxicity of Pseudevernia furfuracea (L.) Zopf by RAPD analysis.

We investigated the suitability and applicability of Pseudevernia furfuracea (L.) Zopf for environmental genotoxicity assessment. P. furfuracea lichen specimens were collected from 10 different Pinus species, in every 5 km, starting from around an iron-steel factory located in the central area of Karabük Province up to Yenice Forest. The impact of the pollution sources such as iron-steel factory, roads and railroads, industry, heavy traffic, and waste treatment plants on the heavy metal accumulation in lichens is known. DNA changes in P. furfuracea samples exposed naturally to various polluted sites were analyzed by RAPD to know the influence of the environmental pollution on the hereditary material of the organisms. Twenty-five different primers were tested and 10 yielded clear and reproducible bands. The present study shows the suitability of the lichen samples for the detection of genotoxicity and also provides information about the level of potential genotoxic agents around a steel mill.

The expression profiles of apoptosis-related genes induced usnic acid in SK-BR-3 breast cancer cell.

This study aims to determine whether usnic acid (UA) could induce the expression of apoptosis-related genes in apoptosis pathway. The current study has enabled us to better understand the target of UA in the treatment of breast cancer. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Based on the previous study and the results of this study, UA had the most antiproliferative effect on SK-BR-3 breast cancer cell line. We examined differential expression of 88 apoptosis-related genes by quantitative real-time polymerase chain reaction using the apoptosis primary library panel in SK-BR-3 breast cancer cell. We observed a difference in the significant differential expression of 74 apoptosis-related genes in breast cancer after SK-BR-3 cells applied to UA (7.21 µM) for 48 h. The expression level of 56 of these 74 differentiated apoptosis-related genes increased (p < 0.05), but the expression level of the other 18 related genes decreased (p < 0.05). In order to evaluate the mechanism of apoptosis of UA, Western blot analysis was performed with Bcl-2, Bax, Caspase-3, and Caspase-9 antibodies. According to the Western blot analysis, we obtained similar results with gene-expression data. These results suggest that UA showed a cytotoxic effect in SK-BR-3 cells through activation of the mitochondrial apoptotic pathway. The obtained results from gene expression revealed that the effect of UA on apoptosis pathway is critical for clinical research.