Guleray Agar

Changes in phytohormone contents in chickpea seeds germinating under lead or zinc stress

The present work describes the changes that take place in phytohormone contents in germinating chickpea (Cicer arietinum cv. Aziziye-94) seeds in response to heavy metal stress. For this aim, endogenous abscisic acid (ABA), gibberellic acid (GA3), zeatin (Z) and zeatin riboside (ZR) contents were followed for 24, 48 and 72 h in chickpea seeds germinating at the concentrations of 0.1, 1.0 and 5.0 mM Pb or 0.1, 1.0 and 10 mM Zn. The results showed that Pb and Zn significantly delayed and impeded the germination of chickpea seeds. The negative effect of Pb on germination was higher than that of Zn. Further, Pb increased ABA and Z contents while decreased GA3 content in the germinating seeds. The high concentrations of Zn (1.0 and 10 mM) decreased contents of Z, ZR and GA3 while 0.1 mM Zn increased the content of the same hormones. The ABA content was enhanced by Zn in all concentrations used.

Mutagenic and antimutagenic effects of hexane extract of some Astragalus species grown in the eastern Anatolia region of Turkey

Medical plants and their various extracts have been occasionally used in the treatment of many diseases. Astragalus is one of those medical plants and it has several biological activities. In the present study, the hexane extracts of six Astragalus species, which are grown in the eastern Anatolia region of Turkey, were isolated, and their mutagenic and antimutagenic properties were investigated by using Salmonella typhimurium TA1535, TA1537 and Escherichia coli WP2uvrA tester strains at 0.05, 0.5 and 5 μg/plate concentrations. Known mutagens sodium azide (NaN3), 9‐Aminoacridine (9‐AA) and N‐Methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG) were used to determine antimutagenic properties of hexane extracts. The results showed that all hexane extracts, investigated in the present study, can be considered genotoxically safe because they do not have mutagenic activity at the tested concentrations. But, a great many of them have antimutagenic activity against 9‐Aminoacridine known as a model intercalator agent. The inhibition rates obtained from the antimutagenicity assays ranged from 27.51% (A. macrocephalus – 0.05 μg/plate) to 54.39% (A. galegiformis – 5 μg/plate). These activities are valuable toward an extension of the employ of these drugs as new phytotherapeutic or preservative ingredients. Copyright

Protective role of methanol extract of Cetraria islandica (L.) against oxidative stress and genotoxic effects of AFB1 in human lymphocytes in vitro

In this study, the antigenotoxic and antioxidant effects of Cetraria islandica methanol (CME) extract were determined by using sister chromatid exchange (SCE), micronuclei (MN) assays and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and malondialdehyde (MDA) levels against effects of aflatoxin B1 (AFB 1) induced oxidative stress and genotoxicity in human lymphocytes in vitro. The results showed that the frequencies of SCE, MN and MDA level decreased, SOD and GPx activities increased when 5 μg/mL and 10 μg/mL doses of CME were added to AFBı-treated cultures. Also, the present results indicate that CME has strong antioxidative and the antigenotoxicity mechanisms of CME are associated with its antioxidant nature.

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.

Protective role of methanol extracts of two lichens on oxidative and genotoxic damage caused by AFB1 in human lymphocytes in vitro

In this study, the antigenotoxic and antioxidant effects of Umbilicaria vellea (UME) and Xantho somloensis (XME) extracts were determined using sister chromatid exchange (SCE), micronuclei (MN) assays, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and malondialdehyde (MDA) levels against the effects of aflatoxin B1 (AFB1)-induced oxidative stress and genotoxicity in human lymphocytes in vitro. The results showed that the frequencies of SCE, MN, and MDA level decreased, but the activities of SOD and GPx increased when 5 μg/mL and 10 μg/mL doses of UME and XME were added to AFB1-treated cultures. Also the present results indicate that strong antioxidative and the antigenotoxicity mechanisms of UME and XME are associated with its antioxidant nature.

Determination of chemical composition and genotoxic effects of essential oil obtained from Nepeta nuda on Zea mays seedlings.

We aimed to determine the genotoxic potential of essential oil (EO) obtained from Nepeta nuda. The chemical content of EO was measured via gas chromatography/mass spectrometry. The most abundant contents were 4aα,7β,7aα-nepetalactone (18.10%), germacrene (15.68%) and elemol (14.38%). For genotoxic effects of EO, Zea mays’ seeds were exposed to four different concentrations of this oil. Inhibition of root and stem growth were observed with an increase in EO concentrations. Randomly amplified polymorphic DNA (RAPD) method was used to determine the genotoxic effects of EO. Some changes occurred in RAPD profiles of germinated EO-treated seeds. Even though total soluble protein quantity vary, the data observed from the protein profiles of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that there was a little differentiation between band profiles of treated samples and control group. We concluded that the basis of interactions between plants, like allelopathy, may be related with genotoxic effects of EO.

Determination of genomic instability and DNA methylation effects of Cr on maize (Zea mays L.) using RAPD and CRED-RA analysis

In this research, we aimed to evaluate DNA damage levels, DNA methylation, protein and phytohormone levels changes in corn (Zea mays L.) seedlings exposed to chromium nitrate (Cr). The results showed that the used all chromium doses caused a decreasing mitotic index, genomic template stability and soluble protein levels and increasing in RAPDs profile changes (DNA damage) and DNA hypermethylation. In additional, in the high-pressure liquid chromatography analyses, it was also observed that Cr contamination caused a decreasing in the growth-promoting hormones including gibberellic acid (GA), zeatin (ZA) and indole acetic acid (IAA) levels, in contrast to abscisic acid (ABA) level. The results of this experiment have clearly shown that Cr has epigenetic effect as well as genotoxic effect. Some of phytohormones decreasing (GA, ZA and IAA) and especially increasing of ABA levels under Cr stress may be a part of the defense system against the stress.

The protective role of zinc and calcium in Vicia faba seedlings subjected to cadmium stress

The aim of the present study was to evidence the possible antagonistic effect of Zinc (Zn2+) and Calcium (Ca2+) against cadmium (Cd2+)-induced DNA damage by using random amplification of polymorphic DNA (RAPD) and metabolic activities in Vicia faba. The results showed that all doses of Cd2+ (10 -3 M, 10-5 M) caused an increase in polymorphism value and a decrease in genomic template stability (GTS %). In addition, when 10 -4-10-6 M Ca2+, 10-6 M Zn2+ were added together with 10-3 M, 10-4 M, 10-5 M of Cd2+, polymorphism value decreased besides GTS, total protein and chlorophyll content increased. Results suggested that Zn2+ and Ca2+ have an antagonistic effect against Cd2+. The order of the antagonisms of Ca2+, Zn2+ against Cd2+ toxicity was Ca2+ > Zn2+. Especially, the degree of antagonistic effect of Zn2+ against Cd2+ is probably related to its concentration ratio.

Determination of protective role of selenium against aflatoxin B1-induced DNA damage

Selenium is an essential mineral for a healthy life. Appropriate doses of it may undertake a protective role in the organism. In this study, the protective role of selenium (Se4+) against aflatoxin B1 (AFB1)-induced DNA damage was determined using random amplified polymorphic DNA on two plants including Vicia faba and Zea mays. It was observed that the concentrations of 0.1, 0.2 and 0.4 ppm of AFB1 have increased polymorphism value, total chlorophyll inhibition rate (IRc, %) and total protein IR (IRp, %). Unlike protein, chlorophyll contents and genomic template stability were decreased. With the addition of different concentrations (0.8 and 80 ppm) of Se4+ to the treated samples with AFB1, the values return to normal. An 800-ppm concentration of Se4+, on the contrary, could not inhibit the toxicity of AFB1 but caused an increase in toxicity level of AFB1/enhanced the toxicity level of AFB1. Results suggested that Se4+ has an antagonistic effect against AFB1 toxicity and that the degree of antagonistic effect of Se4+ against AFB1 was related to its concentration.

Protective effects of methanol extracts from Cladonia rangiformis and Umbilicaria vellea against known mutagens sodium azide and 9-aminoacridine

Lichens and their various extracts have been occasionally used in the treatment of many diseases. Cladonia rangiformis and Umbilicaria vellea are two important species of these lichens and they have several biological activities. In the present study, methanol extracts of these lichens, which are grown in the Eastern Anatolia Region of Turkey, were isolated, and their mutagenic and antimutagenic properties were investigated by using AMES-Salmonella and Zea mays Root Tip Mitotic Index mutagenicity and antimutagenicity assay systems. Known mutagens sodium azide (NaN3) and 9-Aminoacridine (9-AA) were used to determine antimutagenic properties of methanol extracts. The results showed that all methanol extracts, investigated in the present study, can be considered genotoxically safe because they do not have mutagenic activity at the tested concentrations. Besides, all of them have antimutagenic activity against 9-AA known as a model intercalator agent in the AMES-Salmonella test system. The inhibition rates obtained from the antimutagenicity assays ranged from 37.07% (C. rangiformis—5 µg/plate) to 54.39% (C. rangiformis—5 µg/plate). Furthermore, all the methanol extracts have significant antimutagenic activity against NaN3 mutagenicity in Z. mays Root Tip Mitotic Index assay system. These activities are valuable towards an extension of the employ of these drugs as new phytotherapeutic or preservative ingredients.