A schizokinen (siderochrome) auxotroph of Bacillusmegaterium induced with N-methyl-N′-nitro-N-nitrosoguanidine

Arceneaux, J. Lincoln; Lankford, C. E.

doi:10.1016/0006-291x(66)90166-5

Cited by 21 publications

(9 citation statements)

References 9 publications

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“…Iron uptake assays showed some response to aerobactin-iron; however, the amount of iron taken up from this chelate did not exceed that obtained from FeCl. This is interesting since B. megaterium SK11 is able to grow with only iron salts as the iron source, provided the inoculum is high (2,6). It may be that B. megaterium cannot remove iron from the aerobactin-iron chelate, even though it can transport low levels of this chelate.…”

Section: Discussionmentioning

confidence: 99%

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Hydroxamate Recognition During Iron Transport from Hydroxamate-Iron Chelates

et al. 1973

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Kinetics of radioactive iron transport from three structurally different secondary hydroxamate-iron chelates (schizokinen-iron, produced by Bacillus megaterium ATCC 19213; Desferal-iron, produced by an actinomycete; and aerobactin-iron, produced by Aerobacter aerogenes 62-1) revealed that B. megaterium SK11 (a mutant which cannot synthesize schizokinen) has a specific transport system for utilization of ferric hydroxamates with a recognition capacity based on the chemical structure of the hydroxamate. Both Desferal and schizokinen enhanced iron uptake in this organism; however, Desferal-iron delivered only one-sixth the level of iron incorporated from the schizokinen-iron chelate. Desferal-iron did not generate the rapid rates of iron transport noted with schizokinen-iron at elevated iron concentrations. Assays containing large excesses of either iron-free Desferal or iron-free schizokinen suggested that the iron-free hydroxamate may compete with the ferric hydroxamate for acceptance by the transport system although the system has greater affinity for the iron chelate. Aerobactin-iron did not stimulate iron uptake in B. megaterium SK11 and aerobactin inhibited growth of this organism, indicating that B. megaterium SK11 cannot efficiently process the aerobactin-iron chelate.

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Section: Discussionmentioning

confidence: 99%

“…Bacterial strain and cultivation methods. B. megaterium strain SK11, which is unable to produce the secondary hydroxamate schizokinen (2,6) was the test organism. It was cultivated in a sucrose-mineral salts medium, treated with the metal chelating resin Chelex 100 (Bio-Rad Laboratories, Richmond, Calif.) to reduce trace metal contamination.…”

Section: Methodsmentioning

confidence: 99%

Hydroxamate Recognition During Iron Transport from Hydroxamate-Iron Chelates

et al. 1973

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“…The inherent preference of some microorganisms for certain hydroxamates for both iron transport (5, 8) and for growth (1,2) suggests the existence of a special system for transport of hydroxamate-bound iron which has a recognition capacity based on the chemical structure of the hydroxamate. The specificity of this system appears to be alterable by mutation (3,10,17).…”

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confidence: 99%

Fate of Labeled Hydroxamates During Iron Transport from Hydroxamate-Iron Chelates

et al. 1973

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The fate of the hydroxamic acid-iron transport cofactors during iron uptake from the "'Fe3+ chelates of the 'H-labeled hydroxamates schizokinen and aerobactin was studied by assay of simultaneous incorporation of both ",Fe3+ and 3H. In the schizokinen-producing organism Bacillus megaterium ATCC 19213 transport of 59Fe'+ from the 3H-schizokinen-59Fe+ chelate at 37 C was accompanied by rapid uptake and release (within 2 min) of 3H-schizokinen, although 3H-schizokinen discharge was temperature-dependent and did not occur at 0 C. In the schizokinen-requiring strain B. megaterium SK11 similar release of 3H-schizokinen occurred only at elevated concentrations of the double-labeled chelate; at lower chelate concentrations, 'H-schizokinen remained cell-associated. Temperature-dependent uptake of deferri (iron-free) 3H-schizokinen to levels equivalent to those incorporated from the chelate form was noted in strain SK11, but strain ATCC 19213 showed only temperature-independent binding of low concentrations of deferri 3H-schizokinen. These results indicate an initial temperature-independent binding of the ferric hydroxamate which is followed rapidly by temperature-dependent transport of the chelate into the cell and an enzyme catalyzed separation of iron from the chelate. The resulting deferri hydroxamate is discharged from the cell only when a characteristic intracellular concentration of the hydroxamate is exceeded, which happens in the schizokinenrequiring strain only at elevated concentrations of the chelate. This strain also appears to draw the deferri hydroxamate into the cell by a temperature-dependent mechanism. The aerobactin-producing organism Aerobacter aerogenes 62-1 also demonstrated rapid initial uptake and temperature-dependent discharge of 'H-aerobactin during iron transport from 3H-aerobactin-59Fe'+, suggesting a similar ferric hydroxamate transport system in this organism.

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“…Siderophore mutants were isolated by treating cowpea Rhizobium GN1 with NTG as described by Arceneaux [13]. Mutants were screened on chrome azurol-S containing agar plates [14].…”

Section: Isolation Of Siderophore Nonproducing Mutantmentioning

confidence: 99%

Role of siderophore in iron uptake in cowpea Rhizobium GN1 (peanut isolate): Possible involvement of iron repressible outer membrane proteins

Jadhav

1994

FEMS Microbiology Letters

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Siderophore produced by cowpea Rhizobium (3N1 (Peanut isolate) was shown to be involved in iron uptake by this. organism. Siderophore enhanced iron uptake in iron-starved cells. SDS-PAGE analysis of the outer membrane proteins showed two iron repressible outer membrane proteins with approximate molecular mass of 80 kDa and 76 kDa. A siderophore non-producing mutant, which was unable to grow on a medium containing synthetic iron chelators unless and until iron was added exogenously in the medium, could use siderophore of the wild-type for iron uptake indicating that the receptor for Fe-siderophore complex was intact in the mutant.

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A schizokinen (siderochrome) auxotroph of Bacillusmegaterium induced with N-methyl-N′-nitro-N-nitrosoguanidine

Cited by 21 publications

References 9 publications

Hydroxamate Recognition During Iron Transport from Hydroxamate-Iron Chelates

Hydroxamate Recognition During Iron Transport from Hydroxamate-Iron Chelates

Fate of Labeled Hydroxamates During Iron Transport from Hydroxamate-Iron Chelates

Role of siderophore in iron uptake in cowpea Rhizobium GN1 (peanut isolate): Possible involvement of iron repressible outer membrane proteins

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