chloramine-t and malachite-green

A colorimetric assay based on the reduction of 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide (MTT), for the quantification of Tetrahymena sp. survival is described. An increase in the concentration of Tetrahymena sp. cells from 0 to 1 x 10(6) cells/ml produced a linear (R(2)=0.9965) increase in the optical density (OD, 570-630 nm), and dead cells (pre-exposed to 250 mg/l formalin for 4 h) did not produce a background reading. Cells exposed to sublethal concentrations to formalin (100 mg/l or less for 4 h) recovered their growth. Using the MTT assay, we determined that Tetrahymena sp. is sensitive to formalin, chloramine-T, hydrogen peroxide, copper sulfate and NaCl. The sensitivity increased with increasing chemical concentrations and exposure time. Tetrahymena sp. was resistant to bromex and malachite green. The use of this assay in drug screening for the development of treatments for tetrahymenosis and as a bioassay to evaluate the toxicity of environmental toxicants is discussed.

Topics: Animals; Cell Survival; Cells, Cultured; Chloramines; Colorimetry; Copper Sulfate; Drug Evaluation, Preclinical; Environmental Pollutants; Formaldehyde; Hydrogen Peroxide; Rosaniline Dyes; Sodium Chloride; Tetrahymena; Tetrazolium Salts; Thiazoles; Tosyl Compounds

We tested formalin, chloramine-T-formalin and Desirox-formalin, for use against white spot disease (ichthyophthiriasis) caused by Ichthyophthirius multifiliis at 3 salmonid farms (Salmo salar and S. trutta smolt reared in earth ponds). I. multifiliis disappeared from most individuals 4 to 5 wk after the first treatment (and after the first I. multifiliis were found) with all chemicals, indicating that combinations of these chemicals, and even formalin alone, can be used to lower the parasite burden in earth ponds to such a level that no mortality occurs. This was the case when the fish were treated frequently at the beginning of the infection. Treatment can be stopped once the fish have achieved immunity to ichthyophthiriasis. The developing immunity was also revealed by the distribution of ciliates in the course of the disease. At the beginning of the infection I. multifiliis individuals were randomly distributed among the fish, but after 2 to 3 wk, when all the fish were infected, ciliates had increased in numbers and were aggregated in such a way that some fish carried quite heavy burdens. However, over 60% of the fish were free of the parasites after 4 to 5 wk, and had few or no ciliates, meaning that the distribution was even more aggregated. Sea trout had fewer parasites than salmon, and they also recovered from infection earlier even though the treatments and ponds were similar, indicating variation in resistance to I. multifiliis between fish species. It was also evident that the chemicals and their concentrations must be planned carefully to suit the conditions at each farm.

Topics: Animals; Aquaculture; Chloramines; Ciliophora Infections; Fish Diseases; Formaldehyde; Hymenostomatida; Rosaniline Dyes; Salmon; Species Specificity; Tosyl Compounds

In this paper, a new kinetic-spectrophotometric method for the determination of trace amount of iodine has been proposed. It is based on the iodine catalysed the reaction of malachite green oxidized by chloramine T in hydrochloric acid medium. The method is sensitive, simple and with good selectivity. The linear range of determination of iodine is 0-48 micrograms.L-1, the detection limit is 4.9 x 10(-10) g.mL-1. The method has been used for the determination of trace amount of iodine in food with satisfactory results.

Topics: Chloramines; Food Analysis; Iodine; Kinetics; Rosaniline Dyes; Sensitivity and Specificity; Spectrophotometry; Tosyl Compounds