adsorbed materials can be eluted simply by wash- ing the resin with methanol. In the conventional blue cotton procedure, elution is done with am- moniacal methanol. We previously reported the estimation of MeIQx in bacto beef extract by use of this adsorbent. Now the mutagens in aqueous extracts of smoked dry bonito (Katsuo Kezuri- bushi) and of toasted bread were investigated. The methanolic eluates from the resin were further fractionated by TLC and subsequently by HPLC. MeIQx was found in Katsuo Kezuribushi and the content was estimated to be 0.36 ng/g. This amount corresponded approximately to that re- ported in the literature (Kikugawa, K., et al. (1986) Jpn. J. Cancer Res., 77, 99-102). In the extract of toasted bread, a mutagenic component that corre- sponded to Glu-P-2 in terms of both the HPLC retention time and mutagenic characteristics, was found and the content was estimated at 0.47 ng as Glu-P-2/g.

40 Osada, K., and S. Kimura, Laboratory of Nutri- tion, Faculty of Agriculture, Tohoku University, Sendai 980 (Japan)

Characteristics of chemiluminescence from muta- gens in $9 mix

To study a correlation between the mutagenic- ity of polycyclic aromatic hydrocarbons (PAH) and their chemiluminescence intensity, we have examined chemiluminescence emissions of 11 dif- ferent PAHs, benzo[a]pyrene (BP), methyl- cholanthrene (MC), dibenzo[a, i]pyrene, dimethyl- benzanthracene, dibenzanthracene, benzanthra- cene, phenanthrene, benzo[e]pyrene, triphenylene, pyrene and anthracene, in an $9 mix system. It is known that the former 5 reagents have strong mutagenicity in the Ames test, whereas the latter 6 have weak or no mutagenicity. Chemilumines- cence was measured with a Chemiluminescence Analyser OX-71. Significant chemiluminescence was generated during the microsomal metabolism of the former 5 reagents, whereas no significant chemiluminescence was generated with the latter 6. In the cases of BP and MC, the rate of chem- iluminescence emission correlated with the rate of metabolism, which was monitored by reverse-phase

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HPLC. Total chemiluminescence intensity was measured as a function of the concentrations of BP and MC. These integral chemiluminescences resulting from the metabolism of each reagent displayed saturation kinetics. Addition of trichlo- ropropane oxide decreased the chemiluminescence of BP and MC, a fact suggesting that epoxide hydrase is essential for the emission of chemi- luminescence. These results indicate that strongly mutagenic PAHs form many exciplex species such as diol dioxetans and diol epoxides. The formation of these species may be the cause both for the mutagenicity and the chemiluminescence emis- sion.

41 Oya, Y., and K. Yamamoto ~, Department of Pa- thology, Kanagawa Prefectural College of Nursing and Medical Technology, Yokohama 241, and 1 Department of Cytogenetics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113 (Japan)

The clastogenic actions of a histidine-peroxide adduct derived from L-histidine and hydrogen per- oxide

We have previously reported that L-histidine (L-His) enhanced the induction by hydrogen per- oxide (H202) of chromosomal aberrations in hu- man embryonic fibroblasts (Oya et al., 1986; Oya and Yamamoto, in press). The mixture of His and H202 generates a His-H202 adduct at room tem- perature (Dirscherl and Mosebach, 1954). His-H202 adduct thus prepared also showed strong clastogenic actions in a dose-dependent manner in the metaphase cells harvested 27 h after treatment (maximum induction: dicentrics and rings/cell, 1.38). The generation of aberrations by the adduct was suppressed totally by catalase and effectively by several scavengers of hydroxyl radi- cals and singlet oxygens. These induction and suppression modes by the adduct were similar to the results obtained by coadministration of L-His and H202. These results suggest that the enhanc- ing effect of L-His on the clastogenic actions of H202 is due to the formation of this adduct.