Süleyman Cenkci

Toxic chemicals-induced genotoxicity detected by random amplified polymorphic DNA (RAPD) in bean (Phaseolus vulgaris L.) seedlings.

Assessment of genotoxins-induced DNA damage and mutations at molecular level is important in eco-genotoxicology. In this research, RAPD was used to detect DNA damage in the roots and leaves of bean (Phaseolus vulgaris L.) seedlings exposed to toxic chemicals of Hg, B, Cr and Zn (HgCl(2), H(3)BO(3), K(2)Cr(2)O(7) and ZnSO(4)7H(2)O) at concentrations of 150 and 350 ppm for 7 d. Inhibition of shoot and root growth and increase of Hg, B, Cr and Zn element contents in the roots and leaves were observed with an increase in the concentration. For the RAPD analyses, 12 RAPD primers of 60-70% GC content were found to produce unique polymorphic band profiles and subsequently were used to produce a total of 120 bands of 263-3125 bp in the roots and leaves of untreated and treated seedlings. Polymorphisms became evident as disappearance and/or appearance of DNA bands in 150 and 350 ppm treatments compared with untreated control treatments. The DNA changes in RAPD profiles were more in the roots than in the leaves. The highest polymorphism was observed in boric acid treatments among the toxic chemicals. In a dendrogram constructed based on genetic similarity coefficients, the treatments were grouped into three main clusters: (a) root-B-150 ppm treatment grouped alone, (b) root-350 ppm-Hg, B, Cr and Zn treatments clustered together, and (c) the others including untreated control treatments merged together. We concluded that DNA alterations detected by RAPD analysis offered a useful biomarker assay for the evaluation of genotoxic effects of Hg, B, Cr and Zn pollutions on plants.

Evaluation of 2,4-D and Dicamba genotoxicity in bean seedlings using comet and RAPD assays.

The present study was undertaken to evaluate genotoxic potential of two auxinic herbicides [2,4-dicholorophenoxy acetic acid (2,4-D) and 3,6-dichloro-2-methoxybenzoic acid (Dicamba)] in the roots of common bean (Phaseolus vulgaris L.) seedlings. Two-day-old etiolated seedlings were treated with 10 ppm methyl methanesulfonate (MMS, positive control) or 0.1, 0.2, or 0.3 ppm of either 2,4-D or Dicamba. At the end of a 96 h growth period, root growth, total soluble protein content, DNA damage in individual cells (comet assay scores) and randomly amplified polymorphic DNA (RAPD) profiles were used as endpoints of genotoxicity. 2,4-D and Dicamba were clearly dose-dependent root growth inhibitors. Total soluble protein content was significantly decreased in the positive control and at high concentrations (0.2 and 0.3 ppm) of Dicamba. Soluble protein content increased significantly only at 0.3 ppm 2,4-D (P<0.05). In the comet assay, DNA fragmentation increased in a dose-dependent manner. The diagnostic and phenetic analyzes of appeared and/or disappeared RAPD bands indicated that dose-dependent DNA polymorphism was induced by both herbicides. Genomic template stability was significantly affected at all 2,4-D and Dicamba doses tested. Overall 2,4-D and Dicamba have similar effects on DNA damage detected by comet and RAPD assays.

In vitro propagation of an endangered plant species, Thermopsis turcica (Fabaceae)

This report deals with micropropagation of the critically endangered and endemic Turkish shrub, Thermopsis turcica using callus, root and cotyledonary explants. Callus cultures were initiated from root and cotyledon explants on MS medium supplemented with 0.5–20 µM NAA or 2,4-D. The root explants were found to be better in terms of quick responding and callusing percentages as compared to the cotyledons. Organogenic callus production with adventitious roots and shoots were obtained on MS medium with only NAA. The calli obtained with NAA, root and cotyledonary explants were cultured with BA and kinetin (2–8 µM) alone or in combination with a low level (0.5 µM) of 2,4-D or NAA. The best regeneration of shoots from root explants was observed on hormone-free MS medium. NAA with BA or kinetin in the medium improved shoot induction from the calli obtained with NAA. Maximum percentage of shoots (93.3%), maximum number of shoots (6.2) and maximun length of shoots (8.22 cm) were achieved from cotyledonary explants at 4 µM BA and 0.5 µM NAA. The presence of 0.5 µM or higher levels of 2,4-D in shoot induction medium inhibited the regeneration in T. turcica explants. 83% of in vitro rooting was attained on pulsed-IBA treated shoots. The regenerated plants with well developed shoots and roots were successfully acclimatized. Application of this study’s results has the potential to conserve T. turcica from extinction.

Determination of DNA in Certain Salvia Species by Capillary Gel Electrophoresis

This article presents a newly developed capillary gel electrophoresis (CGE) using dynamic coating with hydroxyethylcellulose methodology for the separation of fourteen standard DNA fragments and determination of RAPD-PCR products after a PCR purification clean-up procedure for certain Salvia (sage) species. The developed CGE was successfully applied to the RAPD products of ten different Turkish Salvia (sage) species (Salvia bracteata, S. candidissima, S. ceratophylla, S. dichroantha (endemic), S. forskahlei, S. fruticosa, S. sclarea, S. tomentosa, S. verticillata, and S. viridis). These medicinal plants exhibit a wide range of Turkish flora. The CGE results were compared with those by the slab gel electrophoresis (SGE). The present study offers an alternative CGE method to SGE for the effective separation and evaluation of RAPD-PCR products. This CGE has certain advantages to SGE on the viewpoint of requiring smaller amount of sample and solvent, higher resolution and speed, easier automation, higher sensitivity, and online detection. DNA analysis in Salvia species can help further understanding of their biological functions. In this study, a phylogenetic relationship was analysed by SGE. S. fruticosa and S. dichroantha are genetically the most distant species, and S. bracteata and S. fruticosa are the the most similar species.

Ames and random amplified polymorphic DNA tests for the validation of the mutagenic and/or genotoxic potential of the drinking water disinfection by-products chloroform and bromoform

ABSTRACT Chloroform and Bromoform are two abundant trihalomethanes found in Algerian drinking water. The investigation of the mutagenic hazard of these disinfection by-products was studied by Ames test as prokaryotic bioassay to show their mutagenic effects. For this, Salmonella typhimurium TA98 and TA100 strains were employed. Both chloroform and bromoform showed a direct mutagenic effect since the number of revertant colonies gradually increase in dose-dependent manner with all concentrations tested with the two bacterial strains and these were both in the absence and presence of S9 metabolic activation. The genotoxic hazard was also studied by random amplified polymorphic DNA test on the root cells of Allium cepa as eukaryotic bioassay. DNA extracted from the roots of the onion were incubated at different concentrations of chloroform and bromoform and then amplified by polymerase chain reaction. This was based on demonstrating a major effect of disappearance of bands compared to roots incubated in the negative control (distilled water). The results showed that these two compounds affected genomic DNA by breaks although by mutations.