Influence of light on ochratoxin biosynthesis by Penicillium.
Influence of light on ochratoxin biosynthesis by Penicillium.
复制标题
DOI：
10.1007/s12550-009-0034-y
复制
发表时间：
2010-02-01
影响因子：
3
通讯作者：
Geisen, Rolf
中科院分区：
文献类型：
--
作者：
Schmidt-Heydt, Markus;Bode, Heiko;Geisen, Rolf
光照对青霉菌属赭曲霉毒素的生物合成有重要影响。当在一定强度的恒定日光下孵育时，与在恒定黑暗下孵育相比，赭曲霉毒素A的生物合成减少约20-30%。在昼夜振荡下，赭曲霉毒素A聚酮合酶基因（赭曲霉毒素A生物合成途径的关键基因）有节奏地表达，而且，赭曲霉毒素的量也在恒定黑暗期间或恒定光照期间产生的量之间振荡。这表明赭曲霉毒素A在光照条件下部分降解（20-30%），直到达到一定的下限。此行为取决于光强度。在1，600勒克斯时，只能观察到微弱的影响;然而，在2，800勒克斯时，影响变得显著。在恒定光照条件下生长后，青霉产生的赭曲霉毒素B的量比在恒定黑暗或交替光照/黑暗条件下生长后高5倍。在黑暗中，在增加赭曲霉毒素A的培养基上进行的生长实验表明，外用赭曲霉毒素具有中等毒性。然而，如果在光照条件下进行相同的生长实验，赭曲霉毒素A的生长抑制活性大大增加，表明光放大了赭曲霉毒素的毒性活性。由于赭曲霉毒素A的浓度在夜间和白天培养期间的振荡，青霉菌似乎已经发展出一种适应性机制，以在白天将赭曲霉毒素A的量降低到毒性水平以下。
Light has a profound influence on ochratoxin biosynthesis by Penicillia. When incubated under constant daylight of a certain intensity, ochratoxin A biosynthesis is decreased by about 20-30% compared to incubation under constant darkness. Under day/night oscillation, the ochratoxin A polyketide synthase gene, a key gene of the ochratoxin A biosynthesis pathway, is rhythmically expressed, and moreover, the amount of ochratoxin also oscillates between the amounts produced either during constant darkness or during constant light. This indicates a partial degradation of ochratoxin A (20-30%) under light conditions until a certain lower limit is reached. This behavior is dependent on the light intensity. At 1,600 Lux, only weak effects could be observed; however, at 2,800 Lux, the effects became significant. After growth under constant light conditions, Penicillium produced ochratoxin B at amounts which are 5 times higher than after growth in constant dark or in alternating light/dark conditions. Growth experiments in the dark on medium with increasing amounts of ochratoxin A revealed that externally applied ochratoxin is moderately toxic. However, if the same growth experiments are carried out under light conditions, the growth inhibiting activity of ochratoxin A is greatly increased, indicating that light amplifies the toxic activity of ochratoxin. Because of the oscillation of the concentration of ochratoxin A during night and day incubation, Penicillium seems to have developed an adaptive mechanism to reduce the amount of ochratoxin A during daylight below a toxic level.