@article{oai:ynu.repo.nii.ac.jp:00001633,
 author = {脇田, 正二},
 journal = {横浜国立大学理科紀要. 第二類, 生物学・地学},
 month = {Oct},
 note = {application/pdf, This thesis aims at making inquiries into the thiamine-destruction by mushrooms. 1. Experiments were made on the distribution of thiamine-decomposing factors in mushrooms of 410 species or so belonging to Agaricales, Aphyllo-phorales, Gasteromycetes and Ascomycetes. The author has obtained some evidences which will suggest that the thiamine-decomposing enzyme called "thiaminase" is widely distributed in mushrooms. And some of these mushrooms could decompose 300～900μg of thiamine per 0.1g of their dry matters under an experimental condition given by the author. In result, he has come to find that these thiamine-decomposing factors are strong, particularly in strains such as Russulaceae, Strophariaceae, Cortinariaceae and Tricholomataceae. 2. Experiment were made on the properties of the thiamine-decomposing factors in twenty-five species of mushrooms, of which 0.1g of dried stuff was obsurved to destroy 130～900μg of thiamine under the same experimental conditions as those in the previous experiment. The results obtained are summarized as follows. (1) Almost all the thiamine-decomposing factors of the mushrooms lost their activity when they were heated at 70℃ for one hour, but in Boletus rubellus, a factor was detected, which was so stable as not to lose its activity even when it was heated at 100℃ for one hour. (2) In the seven species of the mushrooms used in the experiment, such as Lactarius piperatus, Hygrocybe acutocanica and so on, a factor was detected, of which thiamine-decomposing activity was remarkably increased by adding aniline. (3) The extract of Laetiporus versisporus notably increased its decomposing power of thiamine, when it was heated at 45℃ for one hour. (4) At least, two or more different thiamine-decomposing factors were detected to exist together in several of the mushrooms. 3. Experiments were made on the thiamine-decomposed products by Laetiporus versisporus, Lactarius piperatus and Boletus rubellus. As above-mentioned, many mushrooms destroyed thiamine, and the thiamine destruction of most of them including Laetiporus versisporus were not stimulated in addition of pyridine. Thiamine-decomposing activities by Boletus rubellus and Lactarius piperatus were remarkably stimulated by adding pyridine. When acetone was added to an extract of the mushroom in the ratio of 3 (the former) to 1 (the latter), two kinds of activity were found both in the precipitate and in the filtrate. Thiamine-decomposed products by these mushrooms were studied by means of gaschromatography. The results obtained are summarized as follows. (1) 4-Methyl-5-β-hydroxyethyl thiazole was found mainly in the ether soluble part of the thiamine-decomposed products. (2) 2-Methyl-4-amino-5-hydroxymethyl pyrimidine was found mainly in the butanol soluble part of the thiamine-decomposed products. (3) In case of Lactarius piperatus, besides a big peak of 4-Methyl-5-β-hydroxyethyl thiazole, some small peaks of unknown substances were found in the chromatogram; however, in the case of adding pyridine in advance in an extract of the mushroom, only one peak of pyrithiamine was found instead of the small peaks of varying retention time. (4) In case of Boletus rubellus, pyrithiamine was not observed in the chromatogram, in the case of adding pyridine in advance to an extraction made from the mushroom. Retention time of the main products produced in the experiment was 3.2 and 11 minutes (pyrithiamine, 2.7) under the experimental condition given by the author. (5) In case of Laetiporus versisporus, peaks of some other unknown substances were found in the chromatogram.},
 pages = {39--70},
 title = {キノコ類のビタミンB_1破壊に関する研究},
 volume = {23},
 year = {1976}
}