Genotoxicity of melanoidin fractions derived from a standard glucose/glycine model

Genotoxic compounds can act at various levels in the cell (causing gene, chromosome, or genome mutations), necessitating the use of a range of genotoxicity assays designed to detect these different types of mutations. The production of melanoidins during the processing and cooking of foods is associated with changes in their nutritional character, and the discovery of mutagenic substances in pyrolyzed protein and amino acids has raised concern about the safety of these foods. The aim of this work was to test melanoidin fractions in three different in vitro assays (Ames test, Vitotox test, and micronucleus test). These melanoidin fractions were produced from the condensation of glucose with glycine and their separation was conducted by dialysis. The crude reaction mixture (before dialysis) and both the LMW and HMW fractions obtained by dialysis showed no genotoxicity in these assays, despite being tested at concentrations much higher than those naturally found in food products. The LMW fraction, however, showed toxicity at these high concentrations. The volatile fraction produced in this reaction showed genotoxicity only in the Vitotox test, at high concentrations.     

Effect of smoke-water and a smoke-isolated butenolide on the growth and genotoxicity of commercial onion

Smoke-water and a biologically active butenolide compound (3-methyl-2H-furo[2,3-c]pyran-2-one) derived from burning plant material, show stimulating effects on a number of agricultural and horticultural crops. In these trials, onion (Allium cepa L.) plants were treated (drenched) with either a 1:500 (v/v) smoke-water solution or a butenolide solution of 10⁻¹⁰ M under greenhouse conditions. Onion plants supplied with smoke-water and butenolide solution exhibited a significantly greater number of leaves, increased leaf length, and a higher fresh and dry leaf weight than untreated plants at 175 days after seed sowing (DASS) (third harvest). In addition, smoke-water and butenolide-treated onion plants exhibited a significantly higher bulb diameter and bulb weight than untreated plants, when these plants were harvested at 175 DASS. Overall, smoke-water was more effective than butenolide and achieved the highest harvest index. Genotoxicity was not detected in the bulbs of onion when they were treated with either smoke-water or butenolide.     

Protective effects of methanolic leaf extracts of Monanthotaxis caffra against aflatoxin B1-induced hepatotoxicity in rats

Aflatoxins are potent hepatotoxic and carcinogenic secondary metabolites produced by toxigenic fungi. The present study investigated the protective effect of methanolic leaf extracts of Monanthotaxis caffra (MLEMC) against aflatoxin B1-induced toxicity in male Sprague-Dawley rats. The rats were randomly divided into 6 groups of 8 animals each. Five groups were administered orally for seven days with three different concentrations of MLEMC (100 mg/kg, 200 mg/kg and 300 mg/kg), curcumin (10 mg/kg) or vehicle (25% propylene glycol). The following day, these groups were administered 1 mg/kg b.w. of aflatoxin B₁ (AFB₁). The experiment was terminated three days after administration of AFB₁. Group 6 represented untreated healthy control. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatinine and liver histopathology were evaluated. Methanolic leaf extracts of M. caffra decreased the levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and creatinine in the sera of rats as compared with the AFB₁ intoxicated group. Co-administration of MLEMC improved the histological characteristics of the hepatocytes in contrast to the AFB₁ treated group, which had mild to severe hepatocellular injuries including bile duct proliferation, bile duct hyperplasia, lymphoplasmacytic infiltrate and fibrosis. Extracts of M. caffra were beneficial in mitigating the hepatotoxic effects of AFB₁ in rats by reducing the levels of liver enzymes and preventing hepatic injury.     

Scale-dependent effects of terrestrial habitat on genetic variation in the great crested newt (Triturus cristatus)

Landscape Ecology - Terrestrial landscapes surrounding aquatic habitat influence the persistence of amphibian spatially structured populations (SSPs) via their crucial role in providing estivation...