Functional Role of PilA in Iron Acquisition in the Cyanobacterium Synechocystis sp. PCC 6803

Lamb, Jacob Joseph; Hill, Ryan E.; Eaton‐Rye, Julian J.; Hohmann‐Marriott, Martin F.

doi:10.1371/journal.pone.0105761

Cited by 35 publications

(37 citation statements)

References 48 publications

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“…Outer‐membrane c ‐type cytochromes and pilin (in bacteria that lack c ‐cytochromes) are crucial for transferring electrons to extracellular electron acceptors, such as Fe(III) oxides, in soils and sediments [ Richardson , ; Reguera et al , ]. In cyanobacteria, pilin (e.g., PilA1) facilitates the donation of electrons to external electron acceptors, such as DOM‐Fe(III) and Fe oxides [ Lamb et al , ]. Pili may also have contributed to the bacterial consumption of DOM‐Fe in our experiments, because Caulobacter can have pili [ Skerker and Shapiro , ].…”

Section: Discussionmentioning

confidence: 99%

The effect of iron on the biodegradation of natural dissolved organic matter

Xiao

Hoikkala²,

Kasurinen

et al. 2016

JGR Biogeosciences

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Iron (Fe) may alter the biodegradation of dissolved organic matter (DOM), by interacting with DOM, phosphorus (P), and microbes. We isolated DOM and a bacterial community from boreal lake water and examined bacterial growth on DOM in laboratory experiments. Fe was introduced either together with DOM (DOM‐Fe) or into bacterial suspension, which led to the formation of insoluble Fe precipitates on bacterial surfaces (Fe coating). In the latter case, the density of planktonic bacteria was an order of magnitude lower than that in the corresponding treatment without introduced Fe. The association of Fe with DOM decreased bacterial growth, respiration, and growth efficiency compared with DOM alone at the ambient concentration of dissolved P (0.16 µmol L−1), indicating that DOM‐associated Fe limited the bioavailability of P. Under a high concentration (21 µmol L−1) of P, bacterial biomass and respiration were similar or several times higher in the treatment where DOM was associated with Fe than in a corresponding treatment without Fe. Based on the next generation sequencing of 16S rRNA genes, Caulobacter dominated bacterial communities grown on DOM‐Fe. This study demonstrated that association of Fe with a bacterial surface or P reduces bacterial growth and the consumption of DOM. In contrast, DOM‐Fe is bioavailable and bound Fe can even stimulate bacterial growth on DOM when P is not limiting.

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Section: Discussionmentioning

confidence: 99%

The effect of iron on the biodegradation of natural dissolved organic matter

Xiao

Hoikkala²,

Kasurinen

et al. 2016

JGR Biogeosciences

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“…[31][32][33] However, many cyanobacteria do not produce siderophores, therefore reductive mechanisms are being sought and evidence of possible reductive iron uptake pathways is growing. [34][35][36][37] New insight on cyanobacterial iron acquisition has revealed ferric reduction due to the action of the Alternate Respiratory Terminal Oxidase (ARTO) in the plasma membrane with the subsequent uptake of ferrous, particularly described for the model cyanobacterium Synechocystis sp. PCC6803, 34,38,39 a common strain used in biophotovoltaics.…”

Section: 29mentioning

confidence: 99%

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

et al. 2018

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The exoelectrogenic capacity of the cyanobacterium Synechococcus elongatus PCC7942 was studied in iron limited growth in order to establish conditions favouring extracellular electron transfer in cyanobacteria for photo-bioelectricity generation. Investigation into extracellular reduction of ferricyanide by Synechococcus elongatus PCC7942 demonstrated enhanced capability for the iron limited conditions in comparison to the iron sufficient conditions. Furtheremore, the significance of pH showed that higher rates of ferricyanide reduction occurred at pH 7, with a 2.7-fold increase with respect to pH 9.5 for iron sufficient cultures and 24-fold increase for iron limited cultures. The strategy presented induced exoelectrogenesis driven mainly by photosynthesis and an estimated redirection of the 28% of electrons from photosynthetic activity was achieved by the iron limited conditions. In addition, ferricyanide reduction in the dark by iron limited cultures also presented a significant improvement, with a 6-fold increase in comparison to iron sufficient cultures. Synechococcus elongatus PCC7942 ferricyanide reduction rates are unprecedented for cyanobacteria and they are comparable to those of microalgae. The redox activity of biofilms directly on ITO-coated glass, in the absence of any artificial mediator, was also enhanced under the iron limited conditions, implying that iron limitation increased exoelectrogenesis at the outer membrane level. Cyclic voltammetry of Synechococcus elongatus PCC7942 biofilms on ITO-coated glass showed a midpoint potential around 0.22 V vs. Ag/ AgCl and iron limited biofilms had the capability to sustain currents in a saturated-like fashion. The present work proposes an iron related exoelectrogenic capacity of Synechococcus elongatus PCC7942 and sets a starting point for the study of this strain in order to improve photo-bioelectricity and darkbioelectricity generation by cyanobacteria, including more sustainable mediatorless systems.

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“…Indeed, Synechocystis normally forms dense colonies on agar, exhibiting log growth and fast doubling times of approximately 8 h (Law et al, 2000;Lamb et al, 2014). This observation suggests that Synechocystis growth regulation differs when cultured on an agar surface or in liquid.…”

Section: Is Stationary Phase Reached Because Of Metabolic/ Nutrient Lmentioning

confidence: 99%

A Novel Mechanism, Linked to Cell Density, Largely Controls Cell Division in Synechocystis

et al. 2017

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ORCID IDs: 0000-0001-7618-4748 (M.I.); 0000-0001-8931-7722 (T.O.); 0000-0002-6113-9570 (R.S.).Many studies have investigated the various genetic and environmental factors regulating cyanobacterial growth. Here, we investigated the growth and metabolism of Synechocystis sp. PCC 6803 under different nitrogen sources, light intensities, and CO 2 concentrations. Cells grown on urea showed the highest growth rates. However, for all conditions tested, the daily growth rates in batch cultures decreased steadily over time, and stationary phase was obtained with similar cell densities. Unexpectedly, metabolic and physiological analyses showed that growth rates during log phase were not controlled primarily by the availability of photoassimilates. Further physiological investigations indicated that nutrient limitation, quorum sensing, light quality, and light intensity (self-shading) were not the main factors responsible for the decrease in the growth rate and the onset of the stationary phase. Moreover, cell division rates in fed-batch cultures were positively correlated with the dilution rates. Hence, not only light, CO 2 , and nutrients can affect growth but also a cell-cell interaction. Accordingly, we propose that cell-cell interaction may be a factor responsible for the gradual decrease of growth rates in batch cultures during log phase, culminating with the onset of stationary phase.

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Functional Role of PilA in Iron Acquisition in the Cyanobacterium Synechocystis sp. PCC 6803

Cited by 35 publications

References 48 publications

The effect of iron on the biodegradation of natural dissolved organic matter

The effect of iron on the biodegradation of natural dissolved organic matter

Tapping into cyanobacteria electron transfer for higher exoelectrogenic activity by imposing iron limited growth

A Novel Mechanism, Linked to Cell Density, Largely Controls Cell Division in Synechocystis

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