阿萨希毛孢子菌体外H_2O_2抗氧化诱导及生物学特性研究

Oxidation resistance and biological characteristics of Trichosporon asahii induced by H_2O_2 in vitro

目的研究体外能否用H_2O_2诱导阿萨希毛孢子菌(T.asahii)产生抗氧化性及诱导获得的抗氧化株的稳定性,并观察诱导过程中菌株的形态、药物敏感性的变化。方法将T.asahii CBS2479、CBS8904在H_2O_2浓度逐渐梯级倍增的YPD液体培养基中传代,直至无法诱导为止;将终末代菌株在不含H_2O_2的YPD液体培养基中连续传10代;观察诱导和回复过程中菌株的酶学、药敏值、形态学变化。结果 CBS2479诱导前CAT值46.89U/mprot,诱导后、回复后分别为(133.00±16.97)、(89.78±22.90)U/mprot;诱导前SOD值178.54U/mprot,诱导后、回复后分别为(534.42±201.91)、(668.78±61.45)U/mprot;CBS8904诱导前CAT值44.06U/mprot,诱导后、回复后分别为(121.17±2.21)、(80.62±23.19)U/mprot;诱导前SOD值226.70U/mprot,诱导后、回复后分别为(569.64±72.52)、(514.12±79.00)U/mprot;诱导末期的菌株对氟康唑和H_2O_2的MIC值为诱导前MIC值的2倍;光镜下可见CBS2479、CBS8904分别由诱导前的菌丝状、孢子状变为诱导后呈假菌丝与孢子混合状态。结论利用浓度梯级倍增的H_2O_2能够诱导出抗氧化的T.asahii菌株,且抗氧化能力相对稳定;诱导后菌株对氟康唑和H_2O_2的耐受力提高,是光镜形态发生变换,出现假菌丝与孢子混合状态。

OBJECTIVE To study whether H2O2 can induce oxidation resistance of Trichosporon asahii in vitro and its oxidative stability.and observe the changes of morphology,and drug sensitivity of the strains.METHODS T.asahii CBS2479,CBS8904 strains were experimentally serially subcultured in YPD medium containing increasing concentrations of H2O2 until not induced.The resistant filial generations were subcultured in drug-free medium for10 times consecutively.The changes of enzyme,morphology,and drug sensitivity of the strains during induction and recovery process were observed.RESULTS The CAT value was 46.89U/mprot before induction of CBS2479,（133.00±16.97）U/mprot after induction,（89.78±22.90）U/mprot after response.The SOD value was 178.54U/mprot before induction,（534.42±201.91）U/mprot after induction,（668.78±61.45）U/mprot after response.The CAT value was 44.06U/mprot before induction of CBS8904,（121.17±2.21）U/mprot after induction,（80.62±23.19）U/mprot after response.The SOD value was 226.70U/mprot before induction,（569.64±72.52）U/mprot after induction,514.12±79.00）U/mprot after response.The MIC value of fluconazole and H2O2 of the strains was as two times during late stage of induction as before the induction.The light microscopy showed that mycelium-like,spore-like CBS2479 and CBS8904transformed to a mixed state of false hyphae and spores after the induction.CONCLUSIONThe stable H2O2-resistant T.asahii strains are successfully induced by increasing concentrations of H2O2,and their antioxidant capacities are relatively stable.After induction,the tolerance of the strains to fluconazole and H2O2 are increased.the light microscopic morphology has changed,showing a mixed state of false hyphae and spores.