Analysis of Sister Chromatid Exchanges and Proliferation of Human Peripheral Blood Lymphocytes Exposed to Epoxiconazole

The potential genotoxic/cytotoxic effect of epoxiconazole was evaluated by means of sister chromatid exchanges (SCE) following the 24 and 48 h in vitro exposure of human peripheral blood lymphocytes to epoxiconazole at concentrations of: 5, 10, 25, 50 and 100 μg. ml–1. Dimethyl sulphoxide (DMSO), used as an epoxiconazole solvent, was used as a negative control and mitomycine (MMC) as a positive control. After the 24-hour exposure, we failed to observe a significant increase in SCE frequencies in comparison with the negative control, however, the concentrations of 10—100 μg.ml–1 caused a significant decrease in the proliferation index (PI; P < 0.001). Also, the 48-hour exposure produced no significant alterations in the SCE frequencies in comparison with the control. At epoxiconazole concentrations ranging from 10 to 50 μg.ml–1 we recorded a moderate to strong, dose-dependent inhibition of PI (P < 0.05; P < 0.01; P < 0.001), while at the highest dose (100 μg.ml–1) the reduction in PI compared to the control was less pronounced (P < 0.05). The reduction in PI at the concentration range of 10—100 μg.ml–1 depended on the number of cells in the M1, M2 and M3 phases of the cell cycle per total number of 100 evaluated metaphases. Our results indicated a significant cytotoxic or cytostatic effect on human peripheral blood lymphocytes

Existence and Stability of Periodic Solution Related to Valveless Pumping

Valveless pumping, also known as Liebau effect, can be described as the unidirectional flow of liquid in a system without valves that is caused by the asymmetry of placing of the periodically working pump. Recently, the research in this field has been reevoked, partially due to its possible application in nanotechnologies. In this paper, a configuration of one pipe and one tank is considered from the mathematical point of view. Qualitative properties of a class of nonlinear differential equations that model the assumed system configuration are investigated. New sufficient conditions for the existence of positive T-periodic solutions are given. Correspondingly, exponential stability of periodic solution is treated. Presented results are new. They extend and complement earlier ones in the literature

Disruption of the chemical communication of the European agrobiont ground-dwelling spider Pardosa agrestis

Lycosid spiders are among the most abundant and diverse insectivores occurring in all agroecosystems. Certain pest management practices, such as the application of pesticides, can disrupt their role in insect pest control. Therefore, understanding the effects of pesticides, including sublethal effects, is essential for the assessment of chemical effects on beneficial arthropods. We investigated the sexual chemical communication of the beneficial agrobiont spider Pardosa agrestis and its disruption by two widely used pesticides, the glyphosate-based herbicide Roundup and the pyrethroid-based insecticide Nurelle D. A two-choice olfactometer and Y-maze were used to study the effectiveness of female airborne and dragline pheromone cues and the disruptive effect of the pesticides. Males of P.agrestis did not locate females via airborne cues, but were very receptive to female dragline silk and male dragline silk. When both female dragline silk and male dragline silk were provided at the same time, the males preferred female silk. Pesticide treatments significantly affected the male ability to follow female cues deposited on dragline silk. The 3-h residues of both Roundup and Nurelle D significantly disrupted the male ability to follow female cues deposited on dragline silk. Treatment by 48-h residues significantly disrupted the male ability only in the case of Nurelle D. Our results demonstrate that pesticides reduce the ability of male spiders to search for a mate due to the disruption of the male's ability to detect the silk cues of the female