Katashi Kenmotsu

Mercury uptake in vivo by normal and acatalasemic mice exposed to metallic mercury vapor (203Hg degrees) and injected with metallic mercury or mercuric chloride (203HgCl2).

Levels of mercury in the brain and liver of acatalasemic mice immediately following exposure to metallic mercury vapor or injection of metallic mercury were higher than those found in normal mice. Acatalasemic mice had decreased levels of mercury in the blood and kidneys when the levels were compared with those of normal mice, which indicated that catalase plays a role in oxidizing and taking up mercury. Thus, the brain/blood or liver/blood ratio of mercury concentration in acatalasemic mice was significantly higher than that of normal mice. These results suggest that metallic mercury in the blood easily passed through the blood-brain or blood-liver barrier. The levels of mercury distribution to the kidneys of normal and acatalasemic mice, 1 hr after injection of mercuric chloride solution, were higher than that of normal and acatalasemic mice, respectively, 1 hr after injection of metallic mercury.

Superoxide radical-induced degradation of polychlorobiphenyls and chlordanes at low temperature

Polychlorobiphenyls (PCBs), have unique physical and chemical properties. It has been found that commercial PCBs have also contained polychlorinated dibenzofuranes (PCDFs) formed under pyrolytic conditions. Disposal of hazardous PCBs, therefore, has resulted in considerable environmental problems because of their extreme resistance to degradation. This paper presents the results of the chemical degradation studies of PCBs and chlordanes in the presence of pyridine, a chain transfer agent using superoxide ion (O{sub 2}{sup {minus}}) produced by the reaction of hydrogen peroxide and sodium metaperiodate at the low temperature (60-75% C). In this degradation method pyridine, the chain transfer agent with the much lower value of the chain transfer constant, was used so as to prolong the life span of O{sub 2}{sup {minus}} and/or the induced PCBs radical. The radical degradation of PCBs was finally promoted.

Mercury oxidation in vitro by ferric compounds.

Among the ferric compounds studied, cytochrome C, methemoglobin, lactoperoxidase, ferritin and ferric ion, in addition to catalase, had the ability to oxidize metallic mercury in the presence of hydrogen peroxide. On the other hand, hematin, the active center of catalase, did not oxidize metallic mercury. The results are consistent with the increased oxidation and uptake of mercury in the liver by acatalasemia mice.

Relationship between uptake of mercury vapor by mushrooms and its catalase activity

The uptake of mercury vapor by mushrooms (Shiitake) artifically grown on an oak tree and the uptake in vitro by catalase extracts prepared from mushroom Hay Bacillus and spinach are reported. Mushrooms were exposed to 1.4 mg/Hg/cu m for 11 days. Measurement of total mercury was as previously described (Ogata et al. 1978, 1979). Levels in mushrooms ranged from 0.4 +/- 0.1 ..mu..g/g at 0.5 days to 4.6 +/- 0.2 ..mu..g/g at 10.5 days and steady-state thereafter. In in vitro studies Hy uptake by mushroom catalase extract was estimated by the perborate method. Uptake was found to parallel catalase activity and was inhibited by potassium cyanide, sodium azide, and 3-amino-1,2,4-triazole. Similar results were obtained with Hay Bacillus and spinach catalase extracts. Results suggest that the level of mercury in the mushroom can be used as an indicator of mercury pollution in the environment. It is also suggested that catalase has an important role in uptake of mercury vapor in the plant. 2 tables (JMT)