Mössbauer spectroscopic study of 57Fe metabolic transformations in the rhizobacterium Azospirillum brasilense Sp245

Kamnev, Alexander A.; Tugarova, Anna V.; Kovács, Krisztina; Bíró, Borbála; Homonnay, Z.; Кузманн, Э.

doi:10.1007/s10751-013-0929-z

Cited by 7 publications

(4 citation statements)

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“…Upon surveying the early literature that addressed metal nutrient uptake and metabolic transformation within live cells of rhizospheric microorganisms, and particularly Azospirilla , we found the number of published works scarce [ 43 , 44 , 45 , 46 ]. It was not until later applications of Mössbauer spectroscopy (reviewed in [ 47 ]) that a greater understanding of microbial demands for iron came to light [ 48 , 49 , 50 , 51 , 52 ]. In this collection, studies using wild-type Sp245 A. brasilense grown aeroponically in cultures containing 57 Fe 3+ -nitrilotriacetate complex showed that live cells reduced 33% of the assimilated Fe 3+ -to-Fe 2+ over an 18 h period of growth [ 48 ].…”

Section: Resultsmentioning

confidence: 99%

“…It was not until later applications of Mössbauer spectroscopy (reviewed in [ 47 ]) that a greater understanding of microbial demands for iron came to light [ 48 , 49 , 50 , 51 , 52 ]. In this collection, studies using wild-type Sp245 A. brasilense grown aeroponically in cultures containing 57 Fe 3+ -nitrilotriacetate complex showed that live cells reduced 33% of the assimilated Fe 3+ -to-Fe 2+ over an 18 h period of growth [ 48 ]. Similarly, wild-type Sp7 A. brasilense bacteria reared under the same conditions reduced 22% of the assimilated Fe 3+ -to-Fe 2+ [ 50 ].…”

Section: Resultsmentioning

confidence: 99%

“…These Mössbauer studies suggested that cellular Fe 3+ was stored in ferritin-like components which was verified in other work [ 49 , 51 ]. Furthermore, these studies showed that Fe 2+ existed in highly coordinated forms [ 48 , 50 ].…”

Section: Resultsmentioning

confidence: 99%

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Studies Using Mutant Strains of Azospirillum brasilense Reveal That Atmospheric Nitrogen Fixation and Auxin Production Are Light Dependent Processes

et al. 2023

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As the use of microbial inoculants in agriculture rises, it becomes important to understand how the environment may influence microbial ability to promote plant growth. This work examines whether there are light dependencies in the biological functions of Azospirillum brasilense, a commercialized prolific grass-root colonizer. Though classically defined as non-phototrophic, A. brasilense possesses photoreceptors that could perceive light conducted through its host’s roots. Here, we examined the light dependency of atmospheric biological nitrogen fixation (BNF) and auxin biosynthesis along with supporting processes including ATP biosynthesis, and iron and manganese uptake. Functional mutants of A. brasilense were studied in light and dark environments: HM053 (high BNF and auxin production), ipdC (capable of BNF, deficient in auxin production), and FP10 (capable of auxin production, deficient in BNF). HM053 exhibited the highest rate of nitrogenase activity with the greatest light dependency comparing iterations in light and dark environments. The ipdC mutant showed similar behavior with relatively lower nitrogenase activity observed, while FP10 did not show a light dependency. Auxin biosynthesis showed strong light dependencies in HM053 and FP10 strains, but not for ipdC. Ferrous iron is involved in BNF, and a light dependency was observed for microbial 59Fe2+ uptake in HM053 and ipdC, but not FP10. Surprisingly, a light dependency for 52Mn2+ uptake was only observed in ipdC. Finally, ATP biosynthesis was sensitive to light across all three mutants favoring blue light over red light compared to darkness with observed ATP levels in descending order for HM053 > ipdC > FP10.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Studies Using Mutant Strains of Azospirillum brasilense Reveal That Atmospheric Nitrogen Fixation and Auxin Production Are Light Dependent Processes

et al. 2023

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“…The bacteria in response activate iron-import, normally with ferric iron-chelating substances under aerobic conditions but delivering ferrous iron into the cytoplasm, to restore the activity of mismetallated enzymes thus preserving the fundamental cellular functions of cells (Beauchene et al 2017). Bacteria do not activate ferrous iron transport systems under aerobic conditions but reduce a significant proportion of ferric-iron assimilated from the media to ferrous-iron during aerobic iron assimilation (Kamnev et al 2014;Beauchene et al 2017). Therefore, the activation of the ferriciron transport system observed in this work by the overexpression of the TonB-dependent receptor could be a potential strategy used by P. putida KT2440 to provide the ferrous-iron required for vital functions during the VBNC state.…”

Section: Discussionmentioning

confidence: 99%

Influence of rehydration on transcriptome during resuscitation of desiccated Pseudomonas putida KT2440

et al. 2020

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Purpose Pseudomonas putida KT2440 is a desiccation-sensitive bacterium that loses culturability after 15 days of air desiccation. We have previously shown that P. putida KT2440 can develop a viable but nonculturable (VBNC) state after being exposed to desiccation stress and eventually recover when desiccated cells are rehydrated for at least 24 h. Methods To determine which genes of transport, oxidation-reduction, and transcription processes could be involved in the return of P. putida KT2440 to the culturable state, a transcriptome analysis was carried out comparing the gene expression of non-desiccated samples with samples subjected to desiccation followed by 20 min of rehydration or desiccation followed by 24 h of rehydration. Results Desiccation stress triggered a VBNC state of P. putida. The major response was detected after 24 h of rehydration with 148 upregulated and 42 downregulated genes. During the VBNC state, P. putida activated transmembrane transport processes like that of siderophores through a TonB-dependent transporter and putative polyhydric alcohol transport systems. Prolonged rehydration with distilled water resuscitated P. putida KT2440 cells activating the catabolism of phenylalanine/tyrosine to provide energy and carbon for ubiquinone biosynthesis while maintaining a reduced protein synthesis. On the other hand, the interruption of the TonB-dependent receptor gene (PP_1446) increased desiccation survival of the mutant strain. Conclusion The activation of the iron transport system (TonB-dependent siderophore receptor) and alcohol transport can be helping the VBNC state of P. putida. Activation of catabolism of phenylalanine/tyrosine and reduced protein synthesis was needed for resuscitation from the VBNC state.

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Evidence for ferritin as dominant iron-bearing species in the rhizobacterium Azospirillum brasilense Sp7 provided by low-temperature/in-field Mössbauer spectroscopy

et al. 2016

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For the ubiquitous diazotrophic rhizobacterium Azospirillum brasilense, which has been attracting the attention of researchers worldwide for the last 35 years owing to its significant agrobiotechnological and phytostimulating potential, the data on iron acquisition and its chemical speciation in cells are scarce. In this work, for the first time for azospirilla, low-temperature (at 80 K, 5 K, as well as at 2 K without and with an external magnetic field of 5 T) transmission Mössbauer spectroscopic studies were performed for lyophilised biomass of A. brasilense (wild-type strain Sp7 grown with (57)Fe(III) nitrilotriacetate complex as the sole source of iron) to enable quantitative chemical speciation analysis of the intracellular iron. In the Mössbauer spectrum at 80 K, a broadened quadrupole doublet of high-spin iron(III) was observed with a few percent of a high-spin iron(II) contribution. In the spectrum measured at 5 K, a dominant magnetically split component appeared with the parameters typical of ferritin species from other bacteria, together with a quadrupole doublet of a superparamagnetic iron(III) component and a similarly small contribution from the high-spin iron(II) component. The Mössbauer spectra recorded at 2 K (with or without a 5 T external field) confirmed the assignment of ferritin species. About 20% of total Fe in the dry cells of A. brasilense strain Sp7 were present in iron(III) forms superparamagnetic at both 5 and 2 K, i.e. either different from ferritin cores or as ferritin components with very small particle sizes.

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Mössbauer spectroscopic study of 57Fe metabolic transformations in the rhizobacterium Azospirillum brasilense Sp245

Cited by 7 publications

References 15 publications

Studies Using Mutant Strains of Azospirillum brasilense Reveal That Atmospheric Nitrogen Fixation and Auxin Production Are Light Dependent Processes

Studies Using Mutant Strains of Azospirillum brasilense Reveal That Atmospheric Nitrogen Fixation and Auxin Production Are Light Dependent Processes

Influence of rehydration on transcriptome during resuscitation of desiccated Pseudomonas putida KT2440

Evidence for ferritin as dominant iron-bearing species in the rhizobacterium Azospirillum brasilense Sp7 provided by low-temperature/in-field Mössbauer spectroscopy

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