Vitreoscilla hemoglobin aidsrespirationunder hypoxic conditionsinitsnativehost

摘要

When Vitreoscilla were growninmediumcontaining60mMsodiumnitriteunderboth normal andlimitedaerationconditions,thelevelsof Vitreoscilla hemoglobin (VHb) were decreasedbygreaterthan90%,whilethelevelsoftheterminalrespiratory oxidase, cytochrome bo, wereincreased350%undernormalaerationand7–23% under limitedaeration.Cytochromefunction,asmeasuredbybothNADHand ubiquinol oxidasesforcellsgrownunderbothconditions,increasedinparallel(by 150–222% and8 56%, respectively,forthetwoactivities).Nitriteinthemedium inhibited Vitreoscilla growth atbothnormalandlimitedaeration.Theinhibitionof VHb at60mMnitritedecreasedwholecellrespirationtothegreatestdegreein stationary phaseforgrowthinlimitedaerationconditions,whichwasthemost oxygen poorconditiontested.Theseresultsareconsistentwiththeoriginally proposed roleforVHb,asanaidtorespirationunderhypoxicconditions. & 2007 ElsevierGmbH.Allrightsreserved.