植物乳杆菌ATCC8014对寄生曲霉NRRL 2999孢子形态及生长与产毒影响的研究

为探讨植物乳杆菌ATCC 80 1 4对寄生曲霉NRRL 2 999生长与产毒的影响 ,将植物乳杆菌与寄生曲霉同时接种到MRS肉汤和预先厌氧培养植物乳杆菌后再接种寄生曲霉孢子 ,2 8℃培养 1 5天。在培养的第3、6、9、1 2和 1 5天测定培养液中的pH值、黄曲霉毒素B1 和菌丝体重量。结果显示 :植物乳杆菌可显著抑制寄生曲霉生长 (P <0 0 1 ) ,抑制的机制在于孢子灭活 ,使其不能发育成菌丝 ,故也不能产生黄曲霉毒素B1 ,在电子显微镜下可观察到寄生曲霉孢子充水肿胀死亡 ,而植物乳杆菌的细胞形态也由长杆状变为椭圆形 ;当植物乳杆菌ATCC 80 1 4接种到已经培养了 3天的寄生曲霉NRRL 2 999培养液中时 ,则植物乳杆菌对其生长与产毒无显著影响。在以乳酸调整的pH4 5MRS肉汤中 ,乳酸对寄生曲霉生长有显著的抑制作用 (P <0 0 1 ) ,但并不影响黄曲霉毒素B1 的合成

Study on the effect of the growth and aflatoxin production by Aspergillus flavus parasiticus NRRL 2999 in the present of Lactobacillus plantarum ATCC 8014

The effect of L. plantarum ATCC 8014 on growth and aflatoxin B1 production of A. flavus subsp. parasiticus NRRL 2999 was studied and determined. A spore suspension of Aspergillus flavus parasiticus NRRL 2999 is inoculated into MRS medium containing L. plantarum and incubated at 28 degrees C for 15 days. The pH of the medium, weight of mycelia and aflatoxin B1 production were determined on day 3, 6, 9, 12, 15 of incubation. The growth of A. flavus subsp. parasiticus NRRL 2999 was inhibited when spores were added to a 24 h L. plantarum ATCC8014 culture and when both organisms were added simultaneously. The inhibition of the growth of A. flavus subsp. parasiticus NRRL 2999 was probably due to inactivating the viability of spores. The spores of A. flavus subsp. parasiticus NRRL 2999 became swollen in the presence of L. plantarum ATCC8014 culture, at the same time, and A. flavus subsp. parasiticus NRRL 2999 also affected the shape of L. plantarum ATCC8014 cells, which became enlarged. However, when L. plantarum ATCC8014 was added to a 3-day A. flavus subsp. parasiticus NRRL 2999 culture, there was not effect on mold growth and aflatoxin B1 production. Lactic acid inhibited growth of A. flavus subsp. culture in the MRS medium with initial pH value of 4.5. However, the production of aflatoxin B1 was not affected.