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Increase in spermine content coordinated with siderophore production in Paracoccus denitrificans
1Department of Medicinal Chemistry, J. Hillis Miller Health Science Center, University of Florida, Gainesville 32610-0485.
Abstract:
Spermine is present in relatively low amounts in Paracoccus denitrificans cultured aerobically in an ammonium succinate minimal salts medium supplemented with 50 microM iron(III). However, in iron-deprived cultures [minimal salts medium containing 0.5 microM iron(III)], spermine content increases by an order of magnitude in coordination with the well-known responses to iron derivation, e.g., derepression of siderophore synthesis and siderophore excretion. When iron-deprived cultures exhibiting both high spermine content and strong siderophore production are reseeded into fresh minimal salts medium containing 50 microM iron[III], both siderophore production and spermine content fall rapidly. Five hours after iron supplementation, spermine is below limits of detection. These results suggest a specific role for spermine in the response of P. denitrificans to low-iron stress.
Insights
Spermine levels significantly increase in Paracoccus denitrificans under iron-deficient conditions, suggesting a role in the bacteria
Area of Science:
- Microbiology
- Bacterial Physiology
- Iron Metabolism
Background:
- Paracoccus denitrificans requires iron for growth.
- Iron availability influences bacterial gene expression and metabolic pathways.
- Siderophores are high-affinity iron chelators produced by many bacteria under iron stress.
Purpose of the Study:
- To investigate the role of spermine in Paracoccus denitrificans.
- To determine the relationship between spermine levels and iron availability.
- To explore spermine's involvement in the bacterial response to low-iron stress.
Main Methods:
- Culturing Paracoccus denitrificans in minimal media with varying iron concentrations.
- Quantifying spermine content under different iron conditions.
- Monitoring siderophore synthesis and excretion.
Main Results:
- Spermine levels were low in iron-replete cultures (50 microM iron).
- Iron-deprived cultures (0.5 microM iron) showed an order of magnitude increase in spermine.
- Upon iron re-supplementation, both spermine and siderophore production rapidly decreased.
Conclusions:
- Spermine accumulation is a specific response to low-iron stress in P. denitrificans.
- Spermine likely plays a functional role in the bacterial adaptation to iron scarcity.
- Further research is warranted to elucidate the precise mechanism of spermine's action.