Specific recombinogenic activity of a new polyene antibiotic.

A new antibiotic from Streptomyces sp., tetrapol A159, active against various fungi, a promising compound for the control of plant diseases, was studied for its genotoxic effects. It was produced at the Institute of Microbiological Preparations for Agriculture, Sofia, Bulgaria. The chemical was tested in three different test systems: a bacterial system, the Ames test for point mutations, the micronucleus test in bone marrow cells of rats for chromosomal aberrations and the fungal system of Aspergillus nidulans for mitotic recombination and aneuploidy. No increase in histidine revertants was observed in any of the TA100, TA98, TA1535 and TA1537 strains of Salmonella at concentrations ranging from 1 to 4000 mg/plate. The results were also negative in the micronucleus test of bone marrow cells at concentrations from 124 to 600 mg/kg b.w., whereas a statistically significant threefold increase of mitotic crossovers was found in Aspergillus, at concentrations from 0.5 to 2.5 mg/ml.

Genotoxicity studies on the organophosphorus insecticide chloracetophone.

Chloracetophone (O,O-dimethyl-2,2,2-trichloro-1-(chloroacetoxy)phosphonate), a new insecticide of the organophosphorus group of pesticides, was tested for genotoxicity in a variety of systems with different genetic end-points and varying parameters. The test systems included 2 microbial systems, Salmonella and Aspergillus for point mutations and mitotic segregation, respectively, and human lymphocyte cultures and mammalian bone marrow cells (from rats and hamsters treated acutely and subacutely) for chromosomal aberrations and micronuclei. Chloracetophone was negative in Aspergillus at concentrations of 1-500 micrograms/ml, in human lymphocyte cultures at concentrations of 2.5-40 micrograms/ml, in rats at doses of 420-21 mg/kg b.w. and in hamsters at doses of 210-42 mg/kg b.w. for chromosomal aberrations. It did not cause any increase of micronuclei in human lymphocytes and rat bone marrow cells but did cause a significant increase in hamster bone marrow cells. Chloracetophone induced base-pair substitutions in strain TA100 of Salmonella with and without metabolic activation at a concentration range of 2000-6000 micrograms/plate.

Genotoxic activity of benomyl in different test systems.

Benomyl (methyl-1-[butylcarbamoyl]-2-benzimidazole carbamate), a benzimidazole derivative fungicide, was tested in the Ames test for point mutations; in human lymphocyte cultures for cell division disturbances, chromosomal aberrations, and SCE; in rat bone marrow cells in vivo for micronuclei; and in rats in vivo for dominant lethals. Benomyl was negative in the Ames test. In human lymphocytes, benomyl at concentrations of 0.5, 1.0, and 2.0 micrograms/ml decreased the number of cells undergoing third division whereas at the concentrations of 0.25 to 4.0 micrograms/ml it strongly increased the number of aneuploid cells. Benomyl was also shown to induce sister chromatid exchanges and micronuclei but not chromosome aberrations. Benomyl decreased the number of female rats with implants but did not cause any dominant lethals.

On the genotoxicity of the pesticides Endodan and Kilacar in 6 different test systems.

Two pesticides, the fungicide Endodan (ethylene thiuram monosulphide) and the insecticide-acaricide Kilacar (bis(parachlorophenyl)cyclopropyl methanol), produced or used in the neighbouring countries of Bulgaria and Greece were investigated in a coordinated research programme for their genotoxic effects in a variety of test systems. This included the Ames test, Aspergillus nidulans for mitotic segregation, in vitro human lymphocyte cell cultures for SCE and chromosomal aberrations, in vivo bone marrow cells in hamsters and rats and the dominant lethal test in rats. The genotoxicity of Endodan was found to range from negative to slightly positive in different test systems. At concentrations of 7.5 and 12.0 micrograms/plate together with S9 mix it induced base-pair substitutions in the TA100 strain of Salmonella typhimurium at a rather low level. At a dose of 93 mg/kg b.w. it also caused chromosomal aberrations in acutely treated hamster bone marrow cells. A significant increase of SCE was also found in human lymphocyte cultures at a concentration of 20.0 micrograms/ml. Endodan was found to be negative in A. nidulans for somatic segregation, lymphocyte cultures for chromosomal aberrations and mitotic activity and in rats for dominant lethals and chromosomal aberrations. Kilacar was found to be a weak mutagen in the TA97 strain of S. typhimurium at concentrations of 2.5 and 5.0 micrograms/plate together with S9 mix. At concentrations of 1.0, 1.5 and 2 micrograms/ml Kilacar increased the number of mitotic segregants in A. nidulans by 160%, 220% and 156% respectively over the control. In Syrian hamster bone marrow cells after acute administration at concentrations of 0, 40, 80 and 160 mg/kg, the MI was 5.50, 4.30, 3.10 and 1.30 respectively, and an increase in chromosomal aberrations of about 300% over the control was observed with a concentration of 80 mg/kg. In human lymphocytes no significant changes were observed in either MI or SCE. In the dominant lethal test after chronic treatment of male rats at doses of 5.1, 10.2 and 102.0 mg/kg b.w. no significant mutagenic effect was found although a decrease was shown in the percentage of females with implants mated with treated males in the first week.

[Toxicological study of the long-term effects of the antioxidant dodecyl gallate on albino rats]. / Toksikologicheskoe izuchenie antiokislitelia dodetsilgallata v usloviiakh dlitel'nogo vozdeistviia na belykh krys.

Toxicity of the antioxidant dodecyl gallate was studied in 150-day experiments on male white rats. The antioxidant was administered intragastrically in doses of 250, 50 and 10 mg/kg bw. The general status and behavior of the animals, the survival rate, weight gain, peripheral blood, the amount of urea, total serum protein, soluble proteins of the liver and kidneys, and activity of enzymes (AST, ALT, LDH, SDH, glucose-6-phosphate dehydrogenase, alkaline and acid phosphatase of the serum, liver and kidneys, the weight of the internal organs) were studied over time, followed by morbid anatomy studies. Quantitative determination of serum lipids (total fats, total cholesterol, esterified cholesterol, free cholesterol, triglycerides, free fatty acids, triglycerides plus free fatty acids, and phospholipids) was made on the 150th day after the onset of experiments. When administered in a dose of 250 mg/kg, dodecyl gallate produced death of the animals and an increase in the content of triglycerides plus free fatty acids, a decrease in the weight of the spleen and morphological alterations in the liver, kidneys and spleen. The dose 50 mg/kg was also toxic. It brought about changes in the activity of serum and liver AST, an increase in the content of TF, TG, FFA, TG plus FFA and phospholipids, a reduction in the weight of the spleen and pathological changes in the liver, kidneys and spleen. The dose 10 mg/kg is regarded as liminal.