Red meats are important animal foods because of their nutritional aspects, but the over-consumption of red meat produces reactive oxygen species (ROS) caused by heme iron and induces colorectal cancer. The effect of orally administered hemin and calcium provided in drinking water for 6 weeks on colon carcinogenesis was observed in male ICR mice. After the mice were acclimated for 1 week, they received three subcutaneous azoxymethane (AOM, 10 mg/kg b.w.) injections weekly and were provided with 2% dextran sodium sulfate (DSS) via drinking water for the next week. The mice were divided into three groups: the control, hemin, and hemin + calcium groups. The orally administered daily dose of hemin was 2 g/kg b.w., and 0.05% calcium was provided daily via drinking water. Colonic mucosa samples were stained with methylene blue, and then, the numbers of aberrant crypt (AC) and aberrant crypt foci (ACF) were counted. Lipid peroxidation in feces was estimated by thiobarbituric acid-reactive substances (TBARS) assay. The total numbers of AC and ACF per colon in the hemin group were significantly higher than those in the control group. Calcium treatment significantly decreased the numbers of ACF and AC in the colon of mice. The TBARS value in the feces of the hemin + calcium group was significantly lower than that in the feces of the hemin group. These results showed that hemin enhances the formation of pre-neoplastic lesions in the colon of mice and that calcium decreases the risk of colon carcinogenesis.

The 5S rRNA gene is considered as valuable resource for chromosome landmarks and evolutionary studies. In this study, the tandem repeat unit of 5S rRNA gene containing the coding sequence and non‐transcribed spacer (NTS) region was amplified by PCR, cloned, and sequenced from Allium wakegi (2n=XY=16) and the two ancestors, A. cepa and A. fistulosum. Although there were intraspecific variations among the clones of each species, we could construct each consensus sequences for A. cepa and A. fistulosum and two consensus sequences for A. wakegi. The sequence of the 120 bp coding region was completely homologous among the consensus sequences from the Allium species examined. However, the sequence in the NTS region was significantly variable and informative in genome analysis. The variations were found to be clustered between the positions 230 and 269, and also distributed broadly as single nucleotide. A. wakegi could be divided into two classes by the 5S rRNA sequences (AWAK‐1 and AWAK‐2). AWAK‐1 showed high homology to the genome of A. cepa and AWAK‐2 to that of A. fistulosum. Fluorescence in situ hybridization technique was applied to analyze the distribution of 5S gene loci. In A. wakegi, 5S rRNA sequences were detected in two different chromosomes, each one showing the pattern identical to the chromosome donated from each genome of both ancestors.