Effect of novel phosphoramidate on growth and respiratory metabolism of Paramecium aurelia.

The continuous increase in the number of new chemicals as well as the discharges of solid and liquid wastes triggered the need for simple and inexpensive bioassays for routine testing. In recent years, there has been increasing development of methods (particularly rapid tests) for testing environmental samples. This paper describes the quick toxic evaluation of a novel synthetic compound: Phosphoramidate derivative B at different concentrations (2, 4 and 8 µM) for 72 h on Paramecium aurelia. We showed that B concentrations affect the growth of Paramecium in concentration- dependent manner; also it decreases the growth rate and increases response percentage in concentration- dependent manner. The value of LC50 obtained for these protozoa was estimated at 4.9693 µM after 24 hours of exposure. The respiratory metabolism of protozoan is perturbed at three concentrations, noting that the oxygen consumption was significantly increased at high concentrations after 18 hours of exposure. The results indicate that the Paramecium toxicity assay could be used as a complementary system to rapidly elucidate the cytotoxic potential of insecticides. The major advantages associated with these tests are: inexpensive, simple, rapid and seem to be attractive alternatives to conventional bioassays.

Evaluation of toxicity of two pesticides: flucycloxuron and diflubenzuron on a cellular model, Paramecium sp.

The effect of two pesticides, the diflubenzuron (DFB) and the Flucycloxuron (FCX) has been studied on a cellular model: Paramecium sp., a ciliated protiste. The treatment with the DFB in the concentrations of 10 and 20 microg/ml reduces the growth of this protiste appreciably. The survey of the respiratory metabolism by the polarography technique (Oxygen electrode) shows a sensitive inhibition of the oxygen consumption by the studied protiste. In the case of the FCX, the treatment with the two concentrations (10 and 20 microg/ml) reveals an inhibition of the ciliated protiste growth; however, this pesticide inhibits the respiratory metabolism of ciliated protiste. This effect is a lot more marked with the FCX that with the DFB. The coloration with neutral red showed a perturbation in cuticle level, translated by the penetration quantity of the color in treated cells, especially at 20 microg/ml of FCX.

Effects of two systemic fungicides: Artea (Propiconazole+cyproconazole) and Punch (Flusilazole) on the physiology and the respiratory metabolism of durum wheat (Triticum durum L.).

The present work aimed at the study of the effects of Artea and Punch; two systemic fungicides on durum Wheat (Triticum durum L. cv. GTA dur). Seeds were grown in a medium containing respectively 25, 50, 75 and 100 ppm of Artea and Punch under controlled conditions. After measuring root number and length, eight-day-old-root tips were used to determine Catalase (EC 1.11.1.6), Ascorbate-Peroxidase (EC 1.11.1.11) and Guaïacol-Peroxidase (EC 1.11.1.7) enzymatic activities. Root respiratory activity was also determined using a polarographic method (Clark electrode). Fungicide treatment triggered a decrease in root number and length for both fungicides. On the other hand, treatment with Artea and Punch resulted in an enhancement of the respiratory activity and increased antioxidative enzymatic levels in durum wheat roots. Activities of Catalase, Ascorbate-Peroxydase and Guaïacol-Peroxydase increased proportionally and were more meaningful at high concentrations (75 and 100 ppm) compared with controls. Modulations in respiratory metabolism and antioxidant system could probably be the result of Artea/Punch-induced toxicity which could lead to an oxidative stress status. The present study enhances previous works relevant to the toxic effects induced by systemic fungicides on plants.

Toxicity of the ammonium nitrate NH4NO3 on the respiratory metabolism of three biological models: parameciums, mosses and lichens.

The inopportune throws out of diverse substances in the atmosphere, constitutes without any doubt the obvious of environmental pollution by man. Among these substances, we are interested in the ammonium nitrate NH4NO3, nitrate fertilizers widely used in farming in our region - Annaba located in the eastern part of Algeria - and manufactured in the same region. In fact, the excessive fertilization, the intensive spreading of animal faeces and the industrial pollution are the accumulation sources of nitrate in vegetables, drilling and the underground waters. The goal of this study is to show the obviousness of a possible toxic effect of NH4NO3 on paramecium an inferior plants resed as biological models. The tests of toxicity were achieved on samples of the area of culture of parameciums. Four concentrations were chosen: 10, 20, 30 and 40 mM, and added before and after appearance of the parameciums in the area. The prepared solutions with the same concentrations of NH4NO3, were used for the dampening of the samples of mosses and lichens. The use of an original technique the polarography allowed us to measure the quantity of oxygen consumed by the organisms in presence of the polluent. The results show that: (i): The treatment by NH4NO3 stimulates the respiratory metabolism of paramecium, (ii): with mosses as well as the measure of the consumption of the oxygen shous the abviousness contrasted with a dampening of respiration but also of the photosynthesis. The perturbation of the respiration and photosynthesis of mousses and lichens can explain the degradation of the plant material and the disappearance of certain species from our ecosystem.