The calcium requirement for functional vesicle development and nitrogen fixation by Frankia strains EAN1pec and CpI1
A calcium requirement was shown for both vesicle development and nitrogenase activity by Frankia strains EAN1pec and CpI1. Washing cells with EGTA or EDTA inhibited both vesicle development and nitrogenase activity. The inhibition of both was reversed by the addition of calcium. A variety of agents known to affect calcium-dependent biological processes, such as a Ca-ATPase inhibitor, Ca-channel blockers, Ca-ionophores, calmodulin antagonists and the local anaesthetics, tetracaine and dibucaine, inhibited nitrogenase activity. Respiratory studies showed that a CN-insensitive respiration process occurred only under nitrogen derepressing conditions. Respiration by NH4Cl-grown cells was completely inhibited by KCN while N2-grown cells were inhibited by only 70%. Removal of calcium ions by EGTA or by the addition of dibucaine or tetracaine blocked the CN-insensitive respiration. This CN-insensitive respiration may be involved in protecting nitrogenase inside the vesicles from oxygen.
Archives of Microbiology
Digital Object Identifier (DOI)
Tisa, L.S. and J.C. Ensign. 1987. The calcium requirement for vesicle development and nitrogen fixation by Frankia strains CpI1 and EAN1pec. Arch. Microbiol. 149:24-29. DOI: 10.1007/BF00423131
© Springer-Verlag 1987