BIOTESTAREA ŞI ESTIMAREA TOXICITĂŢII COMPUŞILOR METALOORAGNICI ASUPRA POPULAŢIEI DE PARAMECIUM CAUDATUM

Ion TODERAŞ*, Aurelian GULEA, Elena ROŞCOV, Olga GARBUZ Universitatea de Stat din Moldova *Institutul de Zoologie al AŞM

Abstract

THE BIOASSAY AND ESTIMATION OF THE TOXICITY OF METALLOORGANIC COMPOUNDS IMPACTING THE POPULATION OF PARAMECIUM CAUDATUM

This work will focus on the study of groups of metalloorganic substances on aquatic organisms. Toxicological testing method of coordination compounds CMT-28 and CMA-18 is used on Paramecium caudatum Ehrnbg ciliates, at concentrations of 100, 10, 1, 0,1, 0,01 uM/L, compared to the prototype. Bioassay method allows us to develop fast and comparative conclusions, avoiding a high risk of errors. The investigation of metalloorganic compounds was performed by the method of serial dilutions in the liquid nutrient medium (1 g nutrient solution / 1l water). As a reference cultures were used ciliates Paramecium caudatum. Infusorians, as objects of research are very comfortable, they reproduce quickly enough, being the most convenient test-objects for study in the laboratory conditions, because of time factor which plays a decisive role and also is more simple to elucidate the impact of abiotic factors (metalloorganic substances) on the process of asexual reproduction of Paramecium caudatum. The activity of substances was evaluated according to the character of the toxicity of the preparations (LT50 and LC50), while the activity of ciliates was studied according to the character of viability and reproductive parameters (increasing or decreasing of numbers and their reproductive rate). The acute toxicity study (LC50 and LT50) of the compounds was performed according to the methodical recommendations on overall toxicity of pharmaceutical remedies. LC50 (lethal concentration, 50%) – concentration which causes death of 50% of test-organisms in a given period of time. LT50 (lethal time, 50%) – time, during which the used concentration of the test compound causes the death of 50% of the test organisms. Keywords: Paramecium caudatum, ciliates, coordination compounds, reproduction, toxicity, numbers, reproduction rate, lethal concentration, lethal time.