Producibility of Aflatoxin by Aspergillus parasiticus in Barley and Their Radiosensitivity

Aspergillus parasiticus에 의한 보리의 Aflatoxin 생성(生成)과 감마선(線)의 영향(影響)

The effect of gamma irradiation on production and accumulation of aflatoxin on natural substrate (barley) by Aspergillus parasiticus NRRL 2999 has been studied in some detail. Gamma irradiation at five doses, 0, 50, 100, 200 and 400 Krad was applied to the grain either soon after moisture equilibration (3 days after inoculation) or 10 days later (13 days after inoculation). And the results were as in the followings. 1. Increase in moisture content from 17% to 25% greatly increased the aflatoxin concentration, especially at zero irradiation dose. 2. Prolongation of the incubation period prior to irradiation from 3 to 13 days resulted in greater accumulation of aflatoxin. 3. Two hundreds Krad applied 13 days after inoculation on barley stored at 25% moisture (100% RH) and $25^{\circ}C$ led to higher aflatoxin production than 100 Krad or even 50 Krad. 4. The relative proportion of the principal aflatoxins in relation to irradiation showed that aflatoxin G was elaborated at a significantly higher rate than aflatoxin B.

Aspergillus parasiticus NRRL 2999에 의한 보리의 aflatoxin생성(生成)에 미치는 코발트-60감마선(線)의 영향(影響)을 조사(調査)하였다. 감마선(線)은 평형수분(平衡水分)된 후(後)(접종(接種) 3일후(日後)), 그리고 10일(日)동안 배양후(培養後) 0, 50, 100, 200 및 400krad로서 조사(照射)하였으며 그 결과(結果)는 다음과 같다. 1. 수분함량(水分含量)이 17%에서 25%로 증가(增加)함으로써 aflatoxin의 생성량(生成量)이 현저(顯著)하게 증가(增加)하였으며, 특히 무조사구(無照射區)에서 크게 증가(增加)하였다. 2. 배양기간(培養期間)을 3일(日)에서 13일(日)로 연장(延長)하여 조사(照射)함으로써 aflatoxin의 생성(生成)이 더욱 증가(增加)하였다. 3. 접종(接種) 13일후(日後) 200krad로 조사(照射)하여 $25^{\circ}C$에서 배양(培養)된 25%수분함량(水分含量)(RH:100%)에서는 50 또는 100krad로 조사(照射)된 것보다 aflatoxin의 생성(生成)이 증가(增加)하였다. 4. Aflatoxin의 종류별(種類別) 축적비율(蓄積比率)은 aflatoxin G가 B보다 현저(顯著)하게 대량(大量)으로 축적(蓄積)되었다.