蓝光诱导促进黑曲霉产糖化酶的研究  

Glucoamylase enhancement regulated by blue light in Aspergillus niger

作　　者：朱俊晨[1] 王小菁[1] 张广[2] 苏捷[3] 朱明[3] 

机构地区：[1]华南师范大学生命科学院,广州510641 [2]清华大学深圳研究生院生命科学部,深圳518055 [3]深圳职业技术学院生物工程系,深圳518055

出　　处：《微生物学报》2006年第5期734-739,共6页Acta Microbiologica Sinica

基　　金：国家自然科学基金(30170558)~~

摘　　要：考察了蓝光对黑曲霉产糖化酶的影响并采用扫描电镜观察蓝光下黑曲霉形态发育过程,结果表明,与黑暗对照组相比,蓝光处理使菌丝粗壮,孢囊增大,分生孢子发育提前,黑曲霉糖化酶活力增加,孢子发育和产糖化酶的进程有一定的对应性。黑曲霉在黑暗下生长至36h时,经蓝光诱导糖化酶产量提高更为明显,提示了黑曲霉存在一个对蓝光反应产生最适光感应的发育阶段,对于光调节黑曲霉产糖化酶来说,蓝光诱导的光强由弱到强,比持续蓝光培养或采用较高光强诱导效果更好,表明黑曲霉产糖化酶存在一种光适应机制,能够感应和适应光强度变化,调节其自身代谢。从抑制性扣除杂交实验和蓝光光强变化对差异基因表达的分析来看,糖化酶基因以及呼吸链中部分氧化还原酶基因在蓝光诱导下表达皆有增强,蓝光信号转导影响了核基因编码的线粒体呼吸链相关酶基因表达水平,交替氧化酶可能参与了蓝光信号途径,影响了黑曲霉产糖化酶和孢子发育。研究结果可为在现有水平上应用蓝光调节提高糖化酶产量找到新的技术突破口和提供新思路。Regulation of glucoamylase production in photoinduced A. niger under blue light were investigated. The results showed that continuous illumination of blue light was effective in promotion of conidiation, leading to more glucoamylase production due to the need of sporulation in A. niger. It was clear that 36h-old mycelium grown in dark was in the developmental stage of formation of conidiophore stalk and was most sensitive to BL A. niger cultures exhibited some competence stage to respond to blue light over a period of 36 h when early conidiophore stalk formed in darkness, and photoinduction at this critical period resulted in relatively higher yield of glucoamylase. The fluence-response data generated with blue light indicated that the optimum fluence required for the photomorphogenetic response in A. niger was no less than 450 （mol/m^2· s） to saturate the photoinduction system. The amount of glucoamylase gene （G1） transcripts accumulated during illumination with blue light was more than that in total darkness, whereas the threshold for G1 induction during illumination with increased gradient light was higher than that exposed directly to light of constant fluence, indicating the existence of a light adaptation mechanism for glucoamyalse production in response to blue light. Nevertheless, both high and low light were able to promote glucoamylase producing. Furthermore, suppression subtractive hybridization experiment revealed that some respiratory chain redox enzymes in mitochondria including alternative oxidase as well as sulfhydryl oxidase participated the photoresponse in A. niger and consequently influenced the metabolism . The results support a possibility of designing strategies to improve giucoamylase yield by application of blue light.

关 键 词：蓝光 黑曲霉 糖化酶 

分 类 号：Q935[生物学—微生物学]