Magnetic resonance microscopy of iron transport in methanogenic granules

Bartacek, Jan; Vergeldt, Frank J.; Gerkema, E.; Jenı́ček, P.; Lens, Piet N.L.; As, Henk Van

doi:10.1016/j.jmr.2009.07.013

Cited by 12 publications

(19 citation statements)

References 38 publications

(74 reference statements)

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“…The metal concentrations used were chosen based on the relaxivity of each metal. Subsequently, the increase of the metal concentration inside the granule was measured using the 3D Turbo Spin Echo (TSE) imaging method developed previously by Mohoric et al (2004) with a spatial resolution of 109 × 109 × 218 µm 3 and a temporal resolution of 11 min as presented in Bartacek et al (2009). The 3D TSE signal was spin-lattice relaxation time (T 1 ) weighted applying a repetition time (T R ) of 200 ms and an echo time (T E ) of 4.53 µs (Bartacek et al, 2009).…”

Section: Experimental Set-up and Mrimentioning

confidence: 99%

“…Thus, an experimental tool for direct measurement of metal transport is required to confirm the validity of these models. Magnetic resonance imaging (MRI) is a nondestructive method that can be applied under in situ conditions to study metal transport in artificial biomatrixes (Nestle, 2002), in phototrophic biofilms (Phoenix and Holmes, 2008) and in methanogenic granules (Bartacek et al, 2009). In addition, MRI can be used to reveal the inner structure of the biofilm and to describe the transport properties (diffusivity) of the water contained in a biofilm matrix (Van As and Van Dusschoten, 1997;Lens and Hemminga, 1998;Van As and Lens, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Transport of various metals and their various chemical species has been measured using MRI in many different porous media such us sandy aquifers (Nestle et al, 2003;Moradi et al, 2008) or various biomatrixes (Donahue et al, 1994;Nestle and Kimmich, 1996;Bartacek et al, 2009). In a previous paper (Bartacek et al, 2009), we described the methodology for MRI measurements in single anaerobic granules using a mixture of Fe 2+ and [FeEDTA] 2− .…”

Section: Introductionmentioning

confidence: 99%

“…In a previous paper (Bartacek et al, 2009), we described the methodology for MRI measurements in single anaerobic granules using a mixture of Fe 2+ and [FeEDTA] 2− . Using this MRI methodology, the present study describes transport of various metals, i.e., cobalt, iron and gadolinium, in liganded or non-liganded form in methanogenic granules.…”

Section: Introductionmentioning

confidence: 99%

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Iron, Cobalt, and Gadolinium Transport in Methanogenic Granules Measured by 3D Magnetic Resonance Imaging

Bartacek

Vergeldt

Máca

et al. 2016

Front. Environ. Sci.

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Description of processes such as bioaccumulation, bioavailability and biosorption of heavy metals in biofilm matrixes requires the quantification of their transport. This study shows 3D MRI measurements of the penetration of free (Fe 2+ , Co 2+ and Gd 3+ ) and complexed ([FeEDTA] 2− and [GdDTPA] 2− ) metal ions in a single methanogenic granule. Interactions (sorption or precipitation) between free metals and the biofilm matrix result in extreme shortening of the spin-spin relaxation time (T 2 ) and a decrease of the amplitude (A 0 ) of the MRI signal, which hampers the quantification of the metal concentration inside the granular sludge matrix. MRI images clearly showed the presence of distinct regions (dead or living biomass, cracks, and precipitates) in the granular matrix, which influenced the metal transport. For the free metal ions, a reactive barrier was formed that moved through the granule, especially in the case of Gd 3+ . Chelated metals penetrated faster and without reaction front. Diffusion of [GdDTPA] 2− could be quantified, revealing the course of its transport and the uneven (0.2-0.4 mmol·L −1 ) distribution of the final [GdDTPA] 2− concentration within the granular biofilm matrix at equilibrium.

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Section: Experimental Set-up and Mrimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Iron, Cobalt, and Gadolinium Transport in Methanogenic Granules Measured by 3D Magnetic Resonance Imaging

Bartacek

Vergeldt

Máca

et al. 2016

Front. Environ. Sci.

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“…Researchers have already used MRI to examine flow dynamics over biofilm surfaces (22,37), metabolite consumption and production (23), the flux of heavy metals in metal-immobilizing bioreactors (15,25), water diffusion in biofilms (28,44), and the transport and fate of metals both in natural and artificial biofilms (28,29) and in real methanogenic granules which are employed in anaerobic wastewater treatment (2).…”

mentioning

confidence: 99%

Application of Paramagnetically Tagged Molecules for Magnetic Resonance Imaging of Biofilm Mass Transport Processes

Ramanan

Holmes

Sloan

et al. 2010

Appl Environ Microbiol

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Molecules become readily visible by magnetic resonance imaging (MRI) when labeled with a paramagnetic tag. Consequently, MRI can be used to image their transport through porous media. In this study, we demonstrated that this method could be applied to image mass transport processes in biofilms. The transport of a complex of gadolinium and diethylenetriamine pentaacetic acid (Gd-DTPA), a commercially available paramagnetic molecule, was imaged both in agar (as a homogeneous test system) and in a phototrophic biofilm. The images collected were T 1 weighted, where T 1 is an MRI property of the biofilm and is dependent on Gd-DTPA concentration. A calibration protocol was applied to convert T 1 parameter maps into concentration maps, thus revealing the spatially resolved concentrations of this tracer at different time intervals. Comparing the data obtained from the agar experiment with data from a one-dimensional diffusion model revealed that transport of Gd-DTPA in agar was purely via diffusion, with a diffusion coefficient of 7.2 ؋ 10 ؊10 m 2 s ؊1 . In contrast, comparison of data from the phototrophic biofilm experiment with data from a twodimensional diffusion model revealed that transport of Gd-DTPA inside the biofilm was by both diffusion and advection, equivalent to a diffusion coefficient of 1.04 ؋ 10 ؊9 m 2 s ؊1 . This technology can be used to further explore mass transport processes in biofilms, either by using the wide range of commercially available paramagnetically tagged molecules and nanoparticles or by using bespoke tagged molecules.

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In situ effective diffusion coefficient profiles in live biofilms using pulsed‐field gradient nuclear magnetic resonance

Renslow

Majors

McLean

et al. 2010

Biotech & Bioengineering

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Diffusive mass transfer in biofilms is characterized by the effective diffusion coefficient. It is well-documented that the effective diffusion coefficient can vary by location in a biofilm. The current literature is dominated by effective diffusion coefficient measurements for distinct cell clusters and stratified biofilms showing this spatial variation. Regardless of whether distinct cell clusters or surface-averaging methods are used, position-dependent measurements of the effective diffusion coefficient are currently: 1) invasive to the biofilm, 2) performed under unnatural conditions, 3) lethal to cells, and/or 4) spatially restricted to only certain regions of the biofilm. Invasive measurements can lead to inaccurate results and prohibit further (time-dependent) measurements which are important for the mathematical modeling of biofilms. In this study our goals were to: 1) measure the effective diffusion coefficient for water in live biofilms, 2) monitor how the effective diffusion coefficient changes over time under growth conditions, and 3) correlate the effective diffusion coefficient with depth in the biofilm. We measured in situ two-dimensional effective diffusion coefficient maps within Shewanella oneidensis MR-1 biofilms using pulsed-field gradient nuclear magnetic resonance methods, and used them to calculate surface-averaged relative effective diffusion coefficient (Drs) profiles. We found that 1) Drs decreased from the top of the biofilm to the bottom, 2) Drs profiles differed for biofilms of different ages, 3) Drs profiles changed over time and generally decreased with time, 4) all the biofilms showed very similar Drs profiles near the top of the biofilm, and 5) the Drs profile near the bottom of the biofilm was different for each biofilm. Practically, our results demonstrate that advanced biofilm models should use a variable effective diffusivity which changes with time and location in the biofilm.

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Magnetic resonance microscopy of iron transport in methanogenic granules

Cited by 12 publications

References 38 publications

Iron, Cobalt, and Gadolinium Transport in Methanogenic Granules Measured by 3D Magnetic Resonance Imaging

Iron, Cobalt, and Gadolinium Transport in Methanogenic Granules Measured by 3D Magnetic Resonance Imaging

Application of Paramagnetically Tagged Molecules for Magnetic Resonance Imaging of Biofilm Mass Transport Processes

In situ effective diffusion coefficient profiles in live biofilms using pulsed‐field gradient nuclear magnetic resonance

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