G. Bronzetti

Antimutagenic effects of chlorophyllin.

It has been suggested that the majority of human cancers are caused by environmental exposures, but little is known about the effective environmental and occupational risks of cancer. It is likely that the process of mutagenesis and the intricate balance between mutagenesis and antimutagenesis are involved in aging, evolution, and other fundamental life processes (15).

METABOLISM OF 5-METHOXYPSORALEN BY Saccharomyces cerevisiae

Incubation of methoxypsoralen (5‐MOP) in the presence of diploid yeast cells (Saccharomyces cerevisiae) before UV‐A exposure leads to an incubation‐time dependent decrease of photoinduced genotoxic effects. The reduction in photoinduced genotoxicity is stronger in cells grown in the presence of 20% glucose and containing high levels of cytochrome P‐450 than in cells grown in the presence of 0.5% glucose and containing undetectable levels of cytochrome P‐450. Inhibition of P‐450 activity by specific inhibitors, such as tetrahydrofuran and metyrapone, strongly affects the observed decrease in 5‐MOP genotoxicity, indicating the involvement of P‐450 in 5‐MOP metabolism. As demonstrated by spectrophotometric and chromatographic (HPLC) analysis during incubation of 5‐MOP with P‐450 containing yeast cells, 5‐MOP gradually disappears from the cell supernatant of the incubation mixture. The reduction in the chromatographic peak corresponding to 5‐MOP is accompanied by the appearance of a new peak that probably corresponds to a metabolite. As shown by the use of P‐450 specific inhibitors, the metabolite appears to be due to P‐450 mediated 5‐MOP metabolisation. Its UV absorption spectrum suggests an alteration of the pyrone moiety of the 5‐MOP molecule.

Genetic and biochemical studies on a commercial preparation of atrazine

A commercial preparation of atrazine was tested in diploid strain (D7) of yeast Saccharomyces cerevisiae in suspension test using cells from logarithmic growth phase (with a high level of cytochrome P‐450) and stationary growth phase. This compound induced a marked increase of both gene conversion and point mutation in logarithmic phase cells, while in stationary phase cells only an increase of gene conversion was observed. Results obtained employing TA98 and TA100 strains of Salmonella typhimurium (Ames test) confirm that atrazine has no mutagenic effect. The in vivo effects on cytochrome P‐450 content (Cyt.P‐450), 7‐ethoxycoumarin‐O‐deethylase (ECD), aminopyrine‐N‐demethylase (APD), p‐nitroanisole‐O‐demethylase (p‐NAD) activities were examined in hepatic microsomes from Naphenobarbital and β‐naphthoflavone induced pigs 24 h after acute intoxication with atrazine. Our results indicated a marked decrease of cytochrome P‐450 level and of microsomal protein content, suggesting a hepatotoxic effect of atrazi...

Zineb: Effects on rat monooxygenase system and genotoxicity in yeast

“In vivo” effects of a commercial preparation of zineb on monooxygenase activities were examined on hepatic microsomes of induced and not induced (basal) rats. Moreover additional “in vitro” experiments with the D7 strain of yeast Saccharomyces cerevisiae and Salmonella typhimurium were performed. Our results show that zineb caused a decrease in cytochrome P‐450 (cyt P‐450) content and in some enzymatic activities such as aminopyrine‐N‐demethylase (APD), p‐nitroanisole‐O‐demethylase (p‐NAD) and aniline hydroxylase (AnH). Immunoblotting analysis, using anti P‐450 2E1 antibodies, confirmed data obtained in AnH activity. Experiments on yeast Saccharomyces cerevisiae showed that zineb induced marked increase of gene conversion and point reverse mutation in logarithmic growth phase cells. Finally, in experiments with Salmonella typhimurium, zineb had not mutagenic effects. It can be concluded from “in vivo” and “in vitro” experiments that zineb has toxic action both in animals, expecially in basal rats, and in...

Antimutagenic Investigations on Commercial Yogurt

The role of diet in the etiology of cancer has received increasing attention in the last ten years (1-5). Consumption of milk reduced the incidence of human stomach cancer induced by alkylating agents (6). Human subjects (7) and experimental animals (8) receiving dietary supplements of Lactobacillus acidophilus exhibited significantly lower levels of fecal enzymes associated with colon carcinogenesis. In addition, extracts prepared from L. bulgaricus, L. casei, and L. acidophilus spent media were shown to inhibit the growth of Sarcoma and Ehrlich tumors, suggesting that lactobacillic cultures have an antitumorigenic effect (9,10).

Genetical and Biochemical Studies on Three Halogenated Ethanes

Chlorinated ethanes as 1,1,1,2-tetrachloroethane (TTCE), hexachloroethane (HCE) and pentachloroethane (PCE) have a wide application in different fields and their use increases every yearl. They are used as accelerators in rubber, retardants in fermentation processes, degreasers and solvents in extraction processes2; moreover, they may occur as intermediates in the production of chlorinated ethylenes. These compounds are diffused in the environment; they have been detected in trace quantities in air, river and drinking-water1,3. Their extensive diffusion and widespread use indicate that human exposure occurs.