1
|
Mohamed A, Sanchez E, Sanchez N, Friesen ML, Beyenal H. Electrochemically Active Biofilms as an Indicator of Soil Health. JOURNAL OF THE ELECTROCHEMICAL SOCIETY 2021; 168:087511. [PMID: 36311278 PMCID: PMC9608337 DOI: 10.1149/1945-7111/ac1e56] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Soil health is a complex phenomenon that reflects the ability of soil to support both plant growth and other ecosystem functions. To our knowledge, research on extracellular electron transfer processes in soil environments is limited and could provide novel knowledge and new ways of monitoring soil health. Electrochemical activities in the soil can be studied by inserting inert electrodes. Once the electrode is polarized to a favorable potential, nearby microorganisms attach to the electrodes and grow as biofilms. Biofilms are a major part of the soil and play critical roles in microbial activity and community dynamics. Our work aims to investigate the electrochemical behavior of healthy and unhealthy soils using chronoamperometry and cyclic voltammetry. We developed a bioelectrochemical soil reactor for electrochemical measurements using healthy and unhealthy soils taken from the Cook Agronomy Farm Long-Term Agroecological Research site; the soils showed similar physical and chemical characteristics, but there was higher plant growth where the healthy soil was taken. Using carbon cloth electrodes installed in these soil reactors, we explored the electrochemical signals in these two soils. First, we measured redox variations by depth and found that reducing conditions were prevalent in healthy soils. Current measurements showed distinct differences between healthy and unhealthy soils. Scanning electron microscopy images showed the presence of microbes attached to the electrode for healthy soil but not for unhealthy soil. Glucose addition stimulated current in both soil types and caused differences in cyclic voltammograms between the two soil types to converge. Our work demonstrates that we can use current as a proxy for microbial metabolic activity to distinguish healthy and unhealthy soil.
Collapse
Affiliation(s)
- Abdelrhman Mohamed
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States of America
| | - Eduardo Sanchez
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States of America
| | - Natalie Sanchez
- Department of Plant Pathology, Washington State University, Pullman, Washington, United States of America
| | - Maren L. Friesen
- Department of Plant Pathology, Washington State University, Pullman, Washington, United States of America
- Department of Crop and Soil Sciences, Washington State University, Pullman, Washington, United States of America
| | - Haluk Beyenal
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States of America
| |
Collapse
|
2
|
Long DM, Frame AK, Reardon PN, Cumming RC, Hendrix DA, Kretzschmar D, Giebultowicz JM. Lactate dehydrogenase expression modulates longevity and neurodegeneration in Drosophila melanogaster. Aging (Albany NY) 2020; 12:10041-10058. [PMID: 32484787 PMCID: PMC7346061 DOI: 10.18632/aging.103373] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 05/14/2020] [Indexed: 11/25/2022]
Abstract
Lactate dehydrogenase (LDH) catalyzes the conversion of glycolysis-derived pyruvate to lactate. Lactate has been shown to play key roles in brain energetics and memory formation. However, lactate levels are elevated in aging and Alzheimer's disease patients, and it is not clear whether lactate plays protective or detrimental roles in these contexts. Here we show that Ldh transcript levels are elevated and cycle with diurnal rhythm in the heads of aged flies and this is associated with increased LDH protein, enzyme activity, and lactate concentrations. To understand the biological significance of increased Ldh gene expression, we genetically manipulated Ldh levels in adult neurons or glia. Overexpression of Ldh in both cell types caused a significant reduction in lifespan whereas Ldh down-regulation resulted in lifespan extension. Moreover, pan-neuronal overexpression of Ldh disrupted circadian locomotor activity rhythms and significantly increased brain neurodegeneration. In contrast, reduction of Ldh in neurons delayed age-dependent neurodegeneration. Thus, our unbiased genetic approach identified Ldh and lactate as potential modulators of aging and longevity in flies.
Collapse
Affiliation(s)
- Dani M Long
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA.,Present address: Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR 97239, USA
| | - Ariel K Frame
- Department of Biology, Western University of London, London N6A 5B7, Ontario, Canada
| | | | - Robert C Cumming
- Department of Biology, Western University of London, London N6A 5B7, Ontario, Canada
| | - David A Hendrix
- Department of Biochemistry and Biophysics, School of Electrical Engineering and Computer Science, Corvallis, OR 97331, USA
| | - Doris Kretzschmar
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR 97239, USA
| | | |
Collapse
|
3
|
Kiamco MM, Mohamed A, Reardon PN, Marean-Reardon CL, Aframehr WM, Call DR, Beyenal H, Renslow RS. Structural and metabolic responses of Staphylococcus aureus biofilms to hyperosmotic and antibiotic stress. Biotechnol Bioeng 2018; 115:1594-1603. [PMID: 29460278 PMCID: PMC5959008 DOI: 10.1002/bit.26572] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 01/10/2018] [Accepted: 02/08/2018] [Indexed: 01/26/2023]
Abstract
Biofilms alter their metabolism in response to environmental stress. This study explores the effect of a hyperosmotic agent-antibiotic treatment on the metabolism of Staphylococcus aureus biofilms through the use of nuclear magnetic resonance (NMR) techniques. To determine the metabolic activity of S. aureus, we quantified the concentrations of metabolites in spent medium using high-resolution NMR spectroscopy. Biofilm porosity, thickness, biovolume, and relative diffusion coefficient depth profiles were obtained using NMR microimaging. Dissolved oxygen concentration was measured to determine the availability of oxygen within the biofilm. Under vancomycin-only treatment, the biofilm communities switched to fermentation under anaerobic condition, as evidenced by high concentrations of formate (7.4 ± 2.7 mM), acetate (13.1 ± 0.9 mM), and lactate (3.0 ± 0.8 mM), and there was no detectable dissolved oxygen in the biofilm. In addition, we observed the highest consumption of pyruvate (0.19 mM remaining from an initial 40 mM concentration), the sole carbon source, under the vancomycin-only treatment. On the other hand, relative effective diffusion coefficients increased from 0.73 ± 0.08 to 0.88 ± 0.08 under vancomycin-only treatment but decreased from 0.71 ± 0.04 to 0.60 ± 0.07 under maltodextrin-only and from 0.73 ± 0.06 to 0.56 ± 0.08 under combined treatments. There was an increase in biovolume, from 2.5 ± 1 mm3 to 7 ± 1 mm3 , under the vancomycin-only treatment, while the maltodextrin-only and combined treatments showed no significant change in biovolume over time. This indicated that physical biofilm growth was halted during maltodextrin-only and combined treatments.
Collapse
Affiliation(s)
- Mia M Kiamco
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
| | - Abdelrhman Mohamed
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
| | - Patrick N Reardon
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington
| | - Carrie L Marean-Reardon
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington
| | - Wrya M Aframehr
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
| | - Douglas R Call
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington
| | - Haluk Beyenal
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
| | - Ryan S Renslow
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington
- Earth and Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington
| |
Collapse
|
4
|
Reardon PN, Walter ED, Marean-Reardon CL, Lawrence CW, Kleber M, Washton NM. Carbohydrates protect protein against abiotic fragmentation by soil minerals. Sci Rep 2018; 8:813. [PMID: 29339803 PMCID: PMC5770415 DOI: 10.1038/s41598-017-19119-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/21/2017] [Indexed: 11/10/2022] Open
Abstract
The degradation and turnover of soil organic matter is an important part of global carbon cycling and of particular importance with respect to attempts to predict the response of ecosystems to global climate change. Thus, it is important to mechanistically understand the processes by which organic matter can be degraded in the soil environment, including contact with reactive or catalytic mineral surfaces. We have characterized the outcome of the interaction of two minerals, birnessite and kaolinite, with two disaccharides, cellobiose and trehalose. These results show that birnessite reacts with and degrades the carbohydrates, while kaolinite does not. The reaction of disaccharides with birnessite produces Mn(II), indicating that degradation of the disaccharides is the result of their oxidation by birnessite. Furthermore, we find that both sugars can inhibit the degradation of a model protein by birnessite, demonstrating that the presence of one organic constituent can impact abiotic degradation of another. Therefore, both the reactivity of the mineral matrix and the presence of certain organic constituents influence the outcomes of abiotic degradation. These results suggest the possibility that microorganisms may be able to control the functionality of exoenzymes through the concomitant excretion of protective organic substances, such as those found in biofilms.
Collapse
Affiliation(s)
- Patrick N Reardon
- Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA. .,OSU NMR Facility, Oregon State University, Corvallis, OR, 97331, USA.
| | - Eric D Walter
- Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Carrie L Marean-Reardon
- Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.,School of the Environment, Washington State University Tri-Cities, Richland, WA, 99352, USA
| | - Chad W Lawrence
- Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Markus Kleber
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR, 97331, USA
| | - Nancy M Washton
- Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| |
Collapse
|
5
|
Bernstein HC, Brislawn C, Renslow RS, Dana K, Morton B, Lindemann SR, Song HS, Atci E, Beyenal H, Fredrickson JK, Jansson JK, Moran JJ. Trade-offs between microbiome diversity and productivity in a stratified microbial mat. THE ISME JOURNAL 2017; 11:405-414. [PMID: 27801910 PMCID: PMC5270574 DOI: 10.1038/ismej.2016.133] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/26/2016] [Accepted: 08/05/2016] [Indexed: 11/08/2022]
Abstract
Productivity is a major determinant of ecosystem diversity. Microbial ecosystems are the most diverse on the planet yet very few relationships between diversity and productivity have been reported as compared with macro-ecological studies. Here we evaluated the spatial relationships of productivity and microbiome diversity in a laboratory-cultivated photosynthetic mat. The goal was to determine how spatial diversification of microorganisms drives localized carbon and energy acquisition rates. We measured sub-millimeter depth profiles of net primary productivity and gross oxygenic photosynthesis in the context of the localized microenvironment and community structure, and observed negative correlations between species richness and productivity within the energy-replete, photic zone. Variations between localized community structures were associated with distinct taxa as well as environmental profiles describing a continuum of biological niches. Spatial regions in the photic zone corresponding to high primary productivity and photosynthesis rates had relatively low-species richness and high evenness. Hence, this system exhibited negative species-productivity and species-energy relationships. These negative relationships may be indicative of stratified, light-driven microbial ecosystems that are able to be the most productive with a relatively smaller, even distributions of species that specialize within photic zones.
Collapse
Affiliation(s)
- Hans C Bernstein
- Chemical and Biological Signature Science, Pacific Northwest National Laboratory, Richland, WA, USA
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Colin Brislawn
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Ryan S Renslow
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Karl Dana
- Chemical and Biological Signature Science, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Beau Morton
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Stephen R Lindemann
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Hyun-Seob Song
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Erhan Atci
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Haluk Beyenal
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - James K Fredrickson
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Janet K Jansson
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - James J Moran
- Chemical and Biological Signature Science, Pacific Northwest National Laboratory, Richland, WA, USA
| |
Collapse
|
6
|
Sultana ST, Call DR, Beyenal H. Maltodextrin enhances biofilm elimination by electrochemical scaffold. Sci Rep 2016; 6:36003. [PMID: 27782161 PMCID: PMC5080540 DOI: 10.1038/srep36003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/22/2016] [Indexed: 01/08/2023] Open
Abstract
Electrochemical scaffolds (e-scaffolds) continuously generate low concentrations of H2O2 suitable for damaging wound biofilms without damaging host tissue. Nevertheless, retarded diffusion combined with H2O2 degradation can limit the efficacy of this potentially important clinical tool. H2O2 diffusion into biofilms and bacterial cells can be increased by damaging the biofilm structure or by activating membrane transportation channels by exposure to hyperosmotic agents. We hypothesized that e-scaffolds would be more effective against Acinetobacter baumannii and Staphylococcus aureus biofilms in the presence of a hyperosmotic agent. E-scaffolds polarized at -600 mVAg/AgCl were overlaid onto preformed biofilms in media containing various maltodextrin concentrations. E-scaffold alone decreased A. baumannii and S. aureus biofilm cell densities by (3.92 ± 0.15) log and (2.31 ± 0.12) log, respectively. Compared to untreated biofilms, the efficacy of the e-scaffold increased to a maximum (8.27 ± 0.05) log reduction in A. baumannii and (4.71 ± 0.12) log reduction in S. aureus biofilm cell densities upon 10 mM and 30 mM maltodextrin addition, respectively. Overall ~55% decrease in relative biofilm surface coverage was achieved for both species. We conclude that combined treatment with electrochemically generated H2O2 from an e-scaffold and maltodextrin is more effective in decreasing viable biofilm cell density.
Collapse
Affiliation(s)
- Sujala T. Sultana
- School of Chemical Engineering & Bioengineering, Washington State University, Pullman, 99164, WA, USA
| | - Douglas R. Call
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, 99164, WA, USA
| | - Haluk Beyenal
- School of Chemical Engineering & Bioengineering, Washington State University, Pullman, 99164, WA, USA
| |
Collapse
|
7
|
Renslow RS, Lindemann SR, Cole JK, Zhu Z, Anderton CR. Quantifying element incorporation in multispecies biofilms using nanoscale secondary ion mass spectrometry image analysis. Biointerphases 2016; 11:02A322. [PMID: 26872582 PMCID: PMC5848783 DOI: 10.1116/1.4941764] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/26/2016] [Accepted: 01/28/2016] [Indexed: 11/17/2022] Open
Abstract
Elucidating nutrient exchange in microbial communities is an important step in understanding the relationships between microbial systems and global biogeochemical cycles, but these communities are complex and the interspecies interactions that occur within them are not well understood. Phototrophic consortia are useful and relevant experimental systems to investigate such interactions as they are not only prevalent in the environment, but some are cultivable in vitro and amenable to controlled scientific experimentation. Nanoscale secondary ion mass spectrometry (NanoSIMS) is a powerful, high spatial resolution tool capable of visualizing the metabolic activities of single cells within a biofilm, but quantitative analysis of the resulting data has typically been a manual process, resulting in a task that is both laborious and susceptible to human error. Here, the authors describe the creation and application of a semiautomated image-processing pipeline that can analyze NanoSIMS-generated data, applied to phototrophic biofilms as an example. The tool employs an image analysis process, which includes both elemental and morphological segmentation, producing a final segmented image that allows for discrimination between autotrophic and heterotrophic biomass, the detection of individual cyanobacterial filaments and heterotrophic cells, the quantification of isotopic incorporation of individual heterotrophic cells, and calculation of relevant population statistics. The authors demonstrate the functionality of the tool by using it to analyze the uptake of (15)N provided as either nitrate or ammonium through the unicyanobacterial consortium UCC-O and imaged via NanoSIMS. The authors found that the degree of (15)N incorporation by individual cells was highly variable when labeled with (15)NH4 (+), but much more even when biofilms were labeled with (15)NO3 (-). In the (15)NH4 (+)-amended biofilms, the heterotrophic distribution of (15)N incorporation was highly skewed, with a large population showing moderate (15)N incorporation and a small number of organisms displaying very high (15)N uptake. The results showed that analysis of NanoSIMS data can be performed in a way that allows for quantitation of the elemental uptake of individual cells, a technique necessary for advancing research into the metabolic networks that exist within biofilms with statistical analyses that are supported by automated, user-friendly processes.
Collapse
Affiliation(s)
- Ryan S Renslow
- Biological Sciences Division, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354
| | - Stephen R Lindemann
- Biological Sciences Division, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354
| | - Jessica K Cole
- Biological Sciences Division, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354
| | - Zihua Zhu
- Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354
| | - Christopher R Anderton
- Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354
| |
Collapse
|