The calcium requirement for functional vesicle development and nitrogen fixation by Frankia strains EAN1pec and CpI1 |
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Authors: | L S Tisa J C Ensign |
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Institution: | (1) Department of Bacteriology, University of Wisconsin, 53706 Madison, WI, USA |
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Abstract: | 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.Abbreviations EDTA
ethylenediaminetetraacetic acid
- EGTA
ethyleneglycol-bis-( amino-ethyl ether) N,N1-tetraacetic acid
- GI
germination inhibitor
- MOPS
3-N-morpholino] propane sulfonic acid
- PCMBS
p-chloromercuribenzene sulphonate
- TMB
8,8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate |
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Keywords: | Frankia Nitrogen fixation Calcium Vesicle development |
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