Genotoxicity of Chlorpyrifos, Alpha-thrin, Efekto virikop and Springbok to onion root tip cells

The pesticides, chlorpyrifos, Alpha-thrin, Efekto virikop and springbok were assessed for cytotoxicity and genotoxicity in the onion root tip assay. Onion seeds were germinated on moistened filter paper inpetri dish at room temperature until radicles appeared. Germinated seeds were exposed to three concentrations of each pesticide for 20 h. About 1 – 2 mm length of root tip was cut, fixed in aceticalcohol, washed in ice cold water, hydrolyzed in warm 1 N HCl, stained with aceto-carmine and squashed on glass slide. For each treatment, about 3000 cells were scored and classified into interphase and normal or aberrant division stage. Cytotoxicity was determined by comparing the mitotic index (MI) of treated cells with that of the negative control. The MI of cells treated with chlorpyrifos, Alpha-thrin or springbok was half or less, that of the control at one or more doses andadjudged cytotoxic. Efekto virikop was not cytotoxic. Genotoxicity was measured by comparing the number of cells/1000 in aberrant division stages at each dose with the negative control using the Mann-Whitney test. Chlorpyrifos was genotoxic (P < 0.05), inducing chromosome lagging and bridges, pulverized and stick chromosomes, multipolar anaphase and telophase. Efekto virikop and springbokinduced lagging chromosomes. Alpha-thrin was not genotoxic

Genotoxic Effects Of Dithane, Malathion And Garden Ripcord On Onion Root Tip Cells

Over the past decade, issues of animal use and care in toxicology research and testing have become one of the fundamental concerns for both science and ethics. Emphasis has been given to the use of alternatives to mammals in testing, research and education. Because plants are direct recipients of agrotoxics and therefore important material for genetic tests and for environmental monitoring of places affected by such pollutants, three doses each of the pesticides, dithane (0.196, 0.391, 0.782 % solution), malathion (0.034, 0.069, 0.137 % solution) and garden ripcord (1.015, 2.030, 4.060 % solution) were assessed for cytotoxicity and genotoxicity to onion root tip cells. The doses represented the LC50 (dose that inhibited 50 % of seeds from germinating), ½ LC50 and ¼ LC50 for each pesticide that were determined in a preliminary dose selection experiment. Onion seeds were germinated on moistened filter paper in a petri dish at room temperature until radicles appeared. Germinated seeds were exposed to three concentrations of each pesticide for 20 hours. About 1-2mm length of root tip was cut, fixed in acetic alcohol, washed in ice cold water, hydrolyzed in warm 1N hydrochloric acid, stained with aceto-carmine and squashed on glass microscope slide. About 3000 cells were scored for each treatment and classified into interphase and normal or aberrant division stage. Cytotoxicity was determined by calculating the mitotic indices and comparing the mitotic indices of treated cells at each dose of each pesticide with that of the negative control group. The mitotic index of the negative control group was reduced to half or less, at the two highest doses of all three pesticides. All three pesticides were therefore cytotoxic to the onion root tip cells. Genotoxicity was measured by comparing the number of cells/1000 in the aberrant division stages at each dose of each pesticide with the number of such cells in the negative control group using the Mann-Whitney statistical test. Dithane was genotoxic (P< 0.05), inducing multipolar anaphases and telophases and lagging chromosomes. Malathion was genotoxic (P< 0.05), inducing lagging chromosomes. Garden ripcord was not genotoxic

Mixed convective flow of unsteady hydromagnetic couple stress fluid through a vertical channel filled with porous medium

In this paper, the mixed convective flow of an electrically conducting, viscous incompressible couple stress fluid through a vertical channel filled with a saturated porous medium has been investigated. The fluid is assumed to be driven by both buoyancy force and oscillatory pressure gradient parallel to the channel plates. A uniform magnetic field of strength 0B is imposed transverse to the channel boundaries. The temperature of the right channel plate is assumed to vary periodically, and the temperature difference between the plates is high enough to induce radiative heat transfer. Under these assumptions, the equations governing the two-dimensional couple stress fluid flow are formulated and exact solutions of the velocity and the temperature fields are obtained. The effects of radiation, Hall current, porous medium permeability and other various flow parameters on the flow and heat transfer are presented graphically and discussed extensively

Convective flow of hydromagnetic couple stress fluid with varying heating through vertical channel

This article addresses the impact of magnetic field induction on the buoyancy-induced oscillatory flow of couple stress fluid with varying heating. Modelled equations for the incompressible fluid are coupled and nonlinear due to the inclusion of viscous heating and thermal effect on the fluid density. Approximate solutions are constructed and coded on a symbolic package to ease the computational complexity. Graphical representations of the symbolic solutions are presented with detailed explanations. Results of the present computation show that the effect of induced magnetic field on the oscillatory flow and heat transfer is significant and cannot be neglected

Mixed Convective Flow of Unsteady Hydromagnetic Couple Stress Fluid Through a Vertical Channel Filled with Porous Medium

In this paper, the mixed convective flow of an electrically conducting, viscous incompressible couple stress fluid through a vertical channel filled with a saturated porous medium has been investigated. The fluid is assumed to be driven by both buoyancy force and oscillatory pressure gradient parallel to the channel plates. A uniform magnetic field of strength 0B is imposed transverse to the channel boundaries. The temperature of the right channel plate is assumed to vary periodically, and the temperature difference between the plates is high enough to induce radiative heat transfer. Under these assumptions, the equations governing the two-dimensional couple stress fluid flow are formulated and exact solutions of the velocity and the temperature fields are obtained. The effects of radiation, Hall current, porous medium permeability and other various flow parameters on the flow and heat transfer are presented graphically and discussed extensively