Resazurin as an indicator of reducing capacity for analyzing the physiologic status of deep-sea bacterium Photobacterium phosphoreum ANT-2200

作者：Jie DAI,Hongzhi TANG,Xuegong LI,Claire-Lise SANTIN,Wenpeng CUI,Na LIU,Xiaoqing QI,Xuehua CUI,Alain GROSSI,Philippe NOTARESCHI,Wei-Jia ZHANG,**,Long-Fei WU

摘要：Resazurin(RZ)is a weakly fl uorescent blue dye and can be reduced irreversibly to highly fl uorescent pink resorufi n(RF)that is reduced reversibly to colorless dihydroresorufi n(hRF)by photodeoxygenation,chemical reaction and reductive organic compounds produced through cell metabolism.Because of the reliable and sensitive fl uorescence-color change and noninvasive features,RZ has been used widely as a redox indicator in cell viability/proliferation assays for bacteria,yeast,and mammalian cells.However,RZ is used rarely for physiological characterization of marine microorganisms.Here,we developed a custom-made irradiation and absorption-analysis device to assess the reducing capacity and physiologic status of marine bacterial cultures.We measured the absorption spectra of RZ,RF,and hRF in the presence of the reducing compound Na 2 S and under visible-light irradiation.After establishing appropriate parameters,we monitored the color changes of RZ and its reduced derivatives to evaluate the coherence between reducing capacity,bioluminescence and growth of the deep-sea bacterium Photobacterium phosphoreum strain ANT-2200 under various conditions.Emission of bioluminescence is an oxidation process dependent upon cellular reducing capacity.Growth and bioluminescence of ANT-2200 cell cultures were impeded progressively with increasing concentrations of RZ,which suggested competition for reducing molecules between RZ at high concentration with reductive metabolism.Therefore,caution should be applied upon direct addition of RZ to growth media to monitor redox reactions in cell cultures.Analyses of the instantaneous reduction velocity of RZ in ANT-2200 cell cultures showed a detrimental eff ect of high hydrostatic pressure and high coherence between the reducing capacity and bioluminescence of cultures.These data clearly demonstrate the potential of using RZ to characterize the microbial metabolism and physiology of marine bacteria.

发文机构：Laboratory of Deep Sea Microbial Cell Biology University of Chinese Academy of Sciences International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms（LIA-MagMC） Aix Marseille University Aix Marseille University

关键词：oxic-reductionindicatorabsorptionspectrabacterialgrowthmarinemicroorganism

分类号： O62[理学—有机化学]