title: Iron nutrition and physiological responses to iron stress in Nitrosomonas europaea.
abstract: Nitrosomonas europaea, as an ammonia-oxidizing bacterium, has a high Fe requirement and has 90 genes dedicated to Fe acquisition. Under Fe-limiting conditions (0.2 microM Fe), N. europaea was able to assimilate up to 70% of the available Fe in the medium even though it is unable to produce siderophores. Addition of exogenous siderophores to Fe-limited medium increased growth (final cell mass). Fe-limited cells had lower heme and cellular Fe contents, reduced membrane layers, and lower NH3- and NH2OH-dependent O2 consumption activities than Fe-replete cells. Fe acquisition-related proteins, such as a number of TonB-dependent Fe-siderophore receptors for ferrichrome and enterobactin and diffusion protein OmpC, were expressed to higher levels under Fe limitation, providing biochemical evidence for adaptation of N. europaea to Fe-limited conditions.
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
authors.forename: Xueming
authors.initials: X
authors.lastname: Wei
authors.forename: Neeraja
authors.initials: N
authors.lastname: Vajrala
authors.forename: Loren
authors.initials: L
authors.lastname: Hauser
authors.forename: Luis A
authors.initials: LA
authors.lastname: Sayavedra-Soto
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Arp
mesh_terms: D000222:Adaptation, Physiological; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D018533:Biomass; D002462:Cell Membrane / Q000648:ultrastructure; D003593:Cytoplasm / Q000737:chemistry; D006418:Heme / Q000032:analysis; D007501:Iron / Q000378:metabolism*; D013058:Mass Spectrometry; D046529:Microscopy, Electron, Transmission; D043370:Nitrosomonas europaea / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D010101:Oxygen Consumption; D018272:Porins / Q000096:biosynthesis / Q000302:isolation & purification; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000302:isolation & purification; D017262:Siderophores / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C113724:OmpC protein; D018272:Porins; D011956:Receptors, Cell Surface; D017262:Siderophores; C035902:siderophore receptors; D006418:Heme; D007501:Iron