Marko Anđelković

Synergistic effect of Gentiana lutea L. on methyl methanesulfonate genotoxicity in the Drosophila wing spot test.

ETHNOPHARMACOLOGICAL RELEVANCE Gentiana lutea L., the yellow gentian, is herb known for its pharmacological properties, with a long tradition of use for the treatment of a variety of diseases including the use as a remedy for digestion, also in food products and in bitter beverages. The aim of the present study is to evaluate, for the first time, genotoxicity of gentian alone, and its antigenotoxicity against methyl methanesulfonate (MMS). MATERIALS AND METHODS The water infusion of the underground part of gentian were evaluated in vivo using the Drosophila wing spot test, at the dose commonly used in traditional medicine. For antigenotoxic study two types of treatment with gentian and MMS were performed: chronic co-treatment, as well as post-treatment with gentian after acute exposure with MMS. RESULTS Water infusion of gentian alone did not exhibit genotoxicity. The results of co- and post-treatment experiments with gentian show that gentian enhanced the frequency of mutant clones over the values obtained with MMS alone, instead of reducing the genotoxicity of MMS, for 22.64% and 27.13% respectively. CONCLUSIONS This result suggests a synergism of gentian with MMS, and indicates that water infusion of gentian used in traditional medicine may have particular effects with regard to genotoxicity indicating careful use.

Sex-specific effects of sympatric mitonuclear variation on fitness in Drosophila subobscura

BackgroundA number of recent studies have shown that the pattern of mitochondrial DNA variation and evolution is at odds with a neutral equilibrium model. Theory has suggested that selection on mitonuclear genotypes can act to maintain stable mitonuclear polymorphism within populations. However, this effect largely relies upon selection being either sex-specific or frequency dependent. Here, we use mitonuclear introgression lines to assess differences in a series of key life-history traits (egg-to-adult developmental time, viability, offspring sex-ratio, adult longevity and resistance to desiccation) in Drosophila subobscura fruit flies carrying one of three different sympatric mtDNA haplotypes.ResultsWe found functional differences between these sympatric mtDNA haplotypes, but these effects were contingent upon the nuclear genome with which they were co-expressed. Further, we demonstrate a significant mitonuclear genetic effect on adult sex ratio, as well as a sex × mtDNA × nuDNA interaction for adult longevity.ConclusionsThe observed effects suggest that sex specific mitonuclear selection contributes to the maintenance of mtDNA polymorphism and to mitonuclear linkage disequilibrium in this model system.

Oxidative stress biomarkers, cholinesterase activity and biotransformation enzymes in the liver of dice snake (Natrix tessellata Laurenti) during pre-hibernation and post-hibernation: A possible correlation with heavy metals in the environment

We investigated in the liver of dice snakes during pre- and post-hibernation changes in the following antioxidant parameters: total, manganese and copper zinc containing superoxide dismutases (Tot SOD, MnSOD, CuZn SOD, respectively), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and the concentrations of total glutathione (GSH) and sulfhydryl groups (-SH). In addition, we examined the expression of phase I biotransformation enzyme cytochrome P4501A (CYP1A) and the activity of phase II biotransformation enzyme glutathioneS-transferase (GST), the level of lipid peroxidation (by measuring the thiobarbituric acid-reactive substances (TBARS)), cholinesterase activity (ChE) and metallothionein expression (MT). We also measured the concentrations of heavy metals, including Al, Cd, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn in the water and snake liver during both periods. During the post-hibernation period, the activities of Tot SOD, CuZn SOD and GST and the concentration of GSH were significantly decreased, while GSH-Px and GR activities, the concentrations of -SH groups and TBARS were significantly increased. The activities of Mn SOD, CAT and ChE, and the relative amounts of CYP1A and MT did not significantly change during the investigated periods. The observed differences in the examined parameters probably represent adaptive physiological responses to sudden changes in tissue oxygenation during arousal from hibernation. Our findings also indicate that the accumulated metals modulated the responses of the examined parameters during the investigated periods.

Adaptive Role of Inversion Polymorphism of Drosophila subobscura in Lead Stressed Environment

Local adaptation to environmental stress at different levels of genetic polymorphism in various plants and animals has been documented through evolution of heavy metal tolerance. We used samples of Drosophila subobscura populations from two differently polluted environments to analyze the change of chromosomal inversion polymorphism as genetic marker during laboratory exposure to lead. Exposure to environmental contamination can affect the genetic content within a particular inversion and produce targets for selection in populations from different environments. The aims were to discover whether the inversion polymorphism is shaped by the local natural environments, and if lead as a selection pressure would cause adaptive divergence of two populations during the multigenerational laboratory experiment. The results showed that populations retain signatures from past contamination events, and that heavy metal pollution can cause adaptive changes in population. Differences in inversion polymorphism between the two populations increased over generations under lead contamination in the laboratory. The inversion polymorphism of population originating from the more polluted natural environment was more stable during the experiment, both under conditions with and without lead. Therefore, results showed that inversion polymorphism as a genetic marker reflects a strong signature of adaptation to the local environment, and that historical demographic events and selection are important for both prediction of evolutionary potential and long-term viability of natural populations.

Locomotor performances reflect habitat constraints in an armoured species

Physical limits of speed performances impose strong selective pressures on animals, influencing important functions such as predator avoidance and foraging success. Armoured herbivorous species such as tortoises represent a peculiar case: features that optimise encounter rate during reproduction, the ability to reach favourable sites for thermoregulation and resting, foraging or nesting sites may be more important than running speed. To explore this issue, we measured three characteristics related to travelling ability but that are independent of running speed: (1) muscular strength, (2) time needed for overturning and (3) jumping from a high step as proxies of the ability to overcome various obstacles. Additionally, reaction times in tortoises placed in a normal or overturned position were measured as a proxy of antipredator response. More than 400 adult Hermann’s tortoises from six populations were tested in the field during two seasons. Measures of travelling ability and antipredator response varied markedly among populations, and thus with environmental characteristics such as habitat type, terrain ruggedness and presence of predators. Tortoises from rugged and hot habitats (e.g. Mediterranean macchia) were the most successful and the fastest to accomplish the tests. Overturned tortoises were more reluctant to start moving compared to those in normal position, but this effect was absent in the two localities free from predators. Sex and season had limited effect on the measured performances. Overall, locomotor features essentially varied with environmental constraints. Future environmental studies should explore whether the observed differences among populations are linked to genetic adaptation or phenotypic plasticity.Significance statementLocomotor performances crucially influence habitat use, foraging and reproductive success, thus directly affecting individual fitness. Although running speed is often considered as a main indicator of agility, in armoured terrestrial vertebrates some other agility components might be more important. Heavy, rigid armour imposes trade-off between protection of soft body parts and locomotor performances and consequently habitat use. This study compiles three tests of locomotor performance which might be important for overcoming various obstacles present in mosaic habitats of tortoises. Testing adult Hermann’s tortoises from six populations with various habitat characteristics, we found significant inter-population differences. The ability of tortoises to complete the tests positively correlates with climatic conditions and topography of their habitats. Additionally, presence of predators in the habitats dramatically affects tortoise’s antipredator behaviour. Measured locomotor performances and antipredator behaviour showed surprisingly low level of sexual dimorphism.