engleski

Effects of UVB-Radiation and Norflurazon on Mesoglea in Green Hydra (Hydra viridissima Pallas, 1766) and in Brown Hydra (Hydra oligactis Pallas, 1766)

Symbiotic green hydra (Hydra viridissima Pallas, 1766) and non-symbiotic brown hydra (Hydra oligactis Pallas, 1766) were exposed to the UVB-radiation and/or herbicide norfluorazon in order to determine their effect on extracellular layer mesoglea. The experiment was performed using crystallizing dishes 60 ml volume with either 50 ml of aquarium water or with two norflurazon solutions (2x10-6 and 2x10- 7 mol/L). Ten individuals of green and brown hydra respectively were placed in separate dishes and five individuals of each species were placed together in a dish. All specimens were exposed to UVBrays with a wavelength of 254 nm for two minutes. The second part of the experiment was performed in the same way except there was no UVB-radiation. Hydras placed in aquarium water were not exposed to the UVB-radiation, as a control group. The experiment was performed in triplicate for 72 hours and hydras were monitored every 24 hours. For slide preparation, standard histological methods were used and slides were stained with hematoxylin and eosin. ImageJ software was used for the morphometric measurements. Thickness of mesoglea was measured at 30 randomly selected segments on the histological slides, per particular treatment. Mesoglea was least thick in the samples of green and brown hydra exposed to UVB-radiation, while the greatest thickness was noted in the group of both species treated with norflurazon concentration of 2x10-7 mol/L. The results indicated that xenobiotics could have an impact on alteration of mesoglea thickness in hydra, which can affect physiological and regenerative processes in symbiotic and non-symbiotic hydras.

norflurazon ; UVB-radiation ; mesoglea ; hydra

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