摘要
以大肠杆菌为试验菌,研究了紫外线杀菌机理。试验结果表明,紫外线照射后,细菌胞壁和胞膜间空隙增宽,胞壁凹凸不平,胞膜通透性增加;琥珀酸脱氢酶与过氧化物酶失活,胸腺嘧啶二聚体形成;在照射剂量小于60000μW·s/cm^2时,可发生光复活。在相同照射剂量下,高强度紫外线对细菌所造成的损伤,一般大于低强度者。
The bactericidal mechanism of ultraviolet ray was studied with Escherichia coli as the test organism. After the E. coli was exposed to high dose (200 (μW / cm^2, 30 min) of ultraviolet ray abnormal change was not observed under scanning electron microscope, but the space between cell wall and cell membrane was found to be widened under transmission electron microscope. Ultraviolet irradiation with low dose (50 μW / cm^2, 1 min ) could increase the permeability of cell membrane and the sensitivity of the bacteria to sodium chloride solution of high concentration. When the bacteria was immersed in 7% sodium chloride solution for half an hour after exposure to 100 μW / cm^2 ultraviolet radiation for 2 min, the cells became shrinked and deformed and the cytoplasm was concentrated. It was indicated in experiment that ultraviolet irradiation could reduce the activities of succinic dehydrogenase and peroxidase of E. coli. After irradiation, the percentage of DNA thymine dimers in E. coli increased significantly. The percentage content of thymine dimers increased with increasing radiation dose and showed negative correlation with survival rate of the bacteria, but stopped increasing after the radiation dose increased to a certain level. With the same dose, ultraviolet ray of high intensity caused higher percentage content of thymine dimers than that of low intensity did. There was photoreactivation phenomena in bactericidal action of ultraviolet irradiation and the rate of photoreactivation could attain 10 ～30%. The higher the radiation dose, the lower the rate of photoreactivation. The phenomena was minimized or disappeared when the radiation dose reached 60 000 μW 鈥?s / cm^2. With the same dose, higher intensity of ultraviolet ray caused lower photoreactivation rate.
出处
《中国消毒学杂志》
CAS
北大核心
1991年第2期76-83,共8页
Chinese Journal of Disinfection
关键词
紫外线
大肠杆菌
杀菌机理
ultraviolet ray Escherichia coli succinic acid dehydrogenase peroxidase bactericidal mechanism thymine dimer photoreactivation
