ABSTRACT
Indole is a very important signal molecule which plays multiple regulatory roles in many physiological and biochemical processes of bacteria, but up to now, the reasons for its wide range of functions have not been revealed. In this study, we found that indole inhibits the motility, promotes glycogen accumulation and enhances starvation resistance of Escherichia coli. However, the regulatory effects of indole became insignificant while the global csrA gene was mutated. To reveal the regulatory relationship between indole and csrA, we studied the effects of indole on the transcription level of csrA, flhDC, glgCAP and cstA, and also the sensing of the promoters of the genes on indole. It was found that indole inhibited the transcription of csrA, and only the promoter of the csrA gene can sense indole. Namely, indole indirectly regulated the translation level of FlhDC, GlgCAP and CstA. These data indicates that indole regulation is related with the regulation of CsrA, which may throw light on the regulation mechanism research of indole.
Subject(s)
Escherichia coli Proteins , Escherichia coli , Escherichia coli/genetics , Escherichia coli/metabolism , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Indoles/pharmacology , Gene Expression Regulation, Bacterial , Repressor Proteins/genetics , Repressor Proteins/metabolismABSTRACT
Growing concerns about food nutrition and food supplies have encouraged the development of effective constituents. Lutein is an important nutrient element, and its health benefits are gradually being recognized. Lutein, as a carotenoid antioxidant, can protect cells and organs from damage caused by free radicals. However, in processing, storage, and usage, lutein is unstable and often undergoes isomerization and oxidative decomposition, which limits its wide range of applications. ß-Cyclodextrin is an ideal substrate to prepare microcapsule structures, which are highly biocompatible and nontoxic. During the lutein encapsulation process, ideal ß-cyclodextrin microcapsules were used to form inclusion compounds. The results reveal that the encapsulation efficiency of the microcapsules reached 53%. Moreover, using ultrasonic-assisted extraction can easily and efficiently purify lutein. In addition, the capability of the ß-cyclodextrin composite shell can enhance the bioactive molecules' activity and stability.
