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Lakey BD, Alberge F, Parrell D, Wright ER, Noguera DR, Donohue TJ. The role of CenKR in the coordination of Rhodobacter sphaeroides cell elongation and division. mBio 2023; 14:e0063123. [PMID: 37283520 PMCID: PMC10470753 DOI: 10.1128/mbio.00631-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 06/08/2023] Open
Abstract
Cell elongation and division are essential aspects of the bacterial life cycle that must be coordinated for viability and replication. The impact of misregulation of these processes is not well understood as these systems are often not amenable to traditional genetic manipulation. Recently, we reported on the CenKR two-component system (TCS) in the Gram-negative bacterium Rhodobacter sphaeroides that is genetically tractable, widely conserved in α-proteobacteria, and directly regulates the expression of components crucial for cell elongation and division, including genes encoding subunit of the Tol-Pal complex. In this work, we show that overexpression of cenK results in cell filamentation and chaining. Using cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), we generated high-resolution two-dimensional (2D) images and three-dimensional (3D) volumes of the cell envelope and division septum of wild-type cells and a cenK overexpression strain finding that these morphological changes stem from defects in outer membrane (OM) and peptidoglycan (PG) constriction. By monitoring the localization of Pal, PG biosynthesis, and the bacterial cytoskeletal proteins MreB and FtsZ, we developed a model for how increased CenKR activity leads to changes in cell elongation and division. This model predicts that increased CenKR activity decreases the mobility of Pal, delaying OM constriction, and ultimately disrupting the midcell positioning of MreB and FtsZ and interfering with the spatial regulation of PG synthesis and remodeling. IMPORTANCE By coordinating cell elongation and division, bacteria maintain their shape, support critical envelope functions, and orchestrate division. Regulatory and assembly systems have been implicated in these processes in some well-studied Gram-negative bacteria. However, we lack information on these processes and their conservation across the bacterial phylogeny. In R. sphaeroides and other α-proteobacteria, CenKR is an essential two-component system (TCS) that regulates the expression of genes known or predicted to function in cell envelope biosynthesis, elongation, and/or division. Here, we leverage unique features of CenKR to understand how increasing its activity impacts cell elongation/division and use antibiotics to identify how modulating the activity of this TCS leads to changes in cell morphology. Our results provide new insight into how CenKR activity controls the structure and function of the bacterial envelope, the localization of cell elongation and division machinery, and cellular processes in organisms with importance in health, host-microbe interactions, and biotechnology.
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Affiliation(s)
- Bryan D. Lakey
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - François Alberge
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Daniel Parrell
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Elizabeth R. Wright
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Cryo-Electron Microscopy Research Center,Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Midwest Center for Cryo-Electron Tomography, Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Daniel R. Noguera
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Timothy J. Donohue
- Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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2
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Fozo EM. Too Much or Not Enough: The Role of mprF in Regulating Overall Phospholipid Content. mBio 2023; 14:e0352722. [PMID: 37022184 PMCID: PMC10127575 DOI: 10.1128/mbio.03527-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
Despite their fundamental role in defining cells, lipids and the contributions of specific lipid classes in bacterial physiology and pathogenesis have not been highlighted well. Enterococcus faecalis, a commensal bacterial and major hospital-acquired bacterium, synthesizes only a few known phospholipids. One of these variants, lysyl-phosphatidylglycerol, is critical for surviving cationic antimicrobial peptides, but its consequence on overall membrane composition and cellular properties has not been thoroughly examined. A recent study by Rashid et al. examines how loss of this lipid class results in an overall shift in total lipid composition and the consequential impacts on the global transcriptome, cellular growth, and secretion. They demonstrate the plasticity of the enterococcal lipidome to reprogram itself to allow for optimal function. With the significant improvements in multiple technological areas, this study, and others like it, provide a template for deciphering the critical function of lipids in all aspects of bacterial physiology.
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Affiliation(s)
- Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Tennesse, USA
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3
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Jawaharraj K, Sigdel P, Gu Z, Muthusamy G, Sani RK, Gadhamshetty V. Photosynthetic microbial fuel cells for methanol treatment using graphene electrodes. ENVIRONMENTAL RESEARCH 2022; 215:114045. [PMID: 35995227 DOI: 10.1016/j.envres.2022.114045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/27/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Photosynthetic microbial fuel cells (pMFC) represent a promising approach for treating methanol (CH3OH) wastewater. However, their use is constrained by a lack of knowledge on the extracellular electron transfer capabilities of photosynthetic methylotrophs, especially when coupled with metal electrodes. This study assessed the CH3OH oxidation capabilities of Rhodobacter sphaeroides 2.4.1 in two-compartment pMFCs. A 3D nickel (Ni) foam modified with plasma-grown graphene (Gr) was used as an anode, nitrate mineral salts media (NMS) supplemented with 0.1% CH3OH as anolyte, carbon brush as cathode, and 50 mM ferricyanide as catholyte. Two simultaneous pMFCs that used bare Ni foam and carbon felt served as controls. The Ni/Gr electrode registered a two-fold lower charge transfer resistance (0.005 kΩ cm2) and correspondingly 16-fold higher power density (141 mW/m2) compared to controls. The underlying reasons for the enhanced performance of R. sphaeroides at the graphene interface were discerned. The real-time polymerase chain reaction (PCR) analysis revealed the upregulation of cytochrome c oxidase, aa3 type, subunit I gene, and Flp pilus assembly protein genes in the sessile cells compared to their planktonic counterparts. The key EET pathways used for sustaining CH3OH oxidation were discussed.
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Affiliation(s)
- Kalimuthu Jawaharraj
- Civil and Environmental Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; Data-Driven Materials Discovery for Bioengineering Innovation Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA
| | - Pawan Sigdel
- Civil and Environmental Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA
| | - Zhengrong Gu
- Agricultural and Biosystems Engineering, South Dakota State University, 2100 University Station, Brookings, SD, 57701, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA
| | - Govarthanan Muthusamy
- Department of Environmental Engineering, Kyungpook National University, Daegu, South Korea, 80 Daehak-ro, Buk-gu, Daegu, South Korea; Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai, 600 077, Tamil Nadu, India
| | - Rajesh Kumar Sani
- Chemical and Biological Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; Data-Driven Materials Discovery for Bioengineering Innovation Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA
| | - Venkataramana Gadhamshetty
- Civil and Environmental Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA; Data-Driven Materials Discovery for Bioengineering Innovation Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, 57701, USA.
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4
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York A, Lloyd AJ, Del Genio CI, Shearer J, Hinxman KJ, Fritz K, Fulop V, Dowson CG, Khalid S, Roper DI. Structure-based modeling and dynamics of MurM, a Streptococcus pneumoniae penicillin resistance determinant present at the cytoplasmic membrane. Structure 2021; 29:731-742.e6. [PMID: 33740396 PMCID: PMC8280954 DOI: 10.1016/j.str.2021.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 01/13/2021] [Accepted: 03/01/2021] [Indexed: 11/28/2022]
Abstract
Branched Lipid II, required for the formation of indirectly crosslinked peptidoglycan, is generated by MurM, a protein essential for high-level penicillin resistance in the human pathogen Streptococcus pneumoniae. We have solved the X-ray crystal structure of Staphylococcus aureus FemX, an isofunctional homolog, and have used this as a template to generate a MurM homology model. Using this model, we perform molecular docking and molecular dynamics to examine the interaction of MurM with the phospholipid bilayer and the membrane-embedded Lipid II substrate. Our model suggests that MurM is associated with the major membrane phospholipid cardiolipin, and experimental evidence confirms that the activity of MurM is enhanced by this phospholipid and inhibited by its direct precursor phosphatidylglycerol. The spatial association of pneumococcal membrane phospholipids and their impact on MurM activity may therefore be critical to the final architecture of peptidoglycan and the expression of clinically relevant penicillin resistance in this pathogen.
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Affiliation(s)
- Anna York
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Adrian J Lloyd
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Charo I Del Genio
- Centre for Fluid and Complex Systems, School of Computing, Electronics and Mathematics, University of Coventry, West Midlands CV1 5FB, UK
| | - Jonathan Shearer
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, UK
| | - Karen J Hinxman
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Konstantin Fritz
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Vilmos Fulop
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Christopher G Dowson
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, UK.
| | - David I Roper
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK; Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA.
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5
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Woodall BM, Harp JR, Brewer WT, Tague ED, Campagna SR, Fozo EM. Enterococcus faecalis Readily Adapts Membrane Phospholipid Composition to Environmental and Genetic Perturbation. Front Microbiol 2021; 12:616045. [PMID: 34093456 PMCID: PMC8177052 DOI: 10.3389/fmicb.2021.616045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 04/15/2021] [Indexed: 11/22/2022] Open
Abstract
The bacterial lipid membrane, consisting both of fatty acid (acyl) tails and polar head groups, responds to changing conditions through alteration of either the acyl tails and/or head groups. This plasticity is critical for cell survival as it allows maintenance of both the protective nature of the membrane as well as functioning membrane protein complexes. Bacteria that live in fatty-acid rich environments, such as those found in the human host, can exploit host fatty acids to synthesize their own membranes, in turn, altering their physiology. Enterococcus faecalis is such an organism: it is a commensal of the mammalian intestine where it is exposed to fatty-acid rich bile, as well as a major cause of hospital infections during which it is exposed to fatty acid containing-serum. Within, we employed an untargeted approach to detect the most common phospholipid species of E. faecalis OG1RF via ultra-high performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). We examined not only how the composition responds upon exposure to host fatty acids but also how deletion of genes predicted to synthesize major polar head groups impact lipid composition. Regardless of genetic background and differing basal lipid composition, all strains were able to alter their lipid composition upon exposure to individual host fatty acids. Specific gene deletion strains, however, had altered survival to membrane damaging agents. Combined, the enterococcal lipidome is highly resilient in response to both genetic and environmental perturbation, likely contributing to stress survival.
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Affiliation(s)
- Brittni M. Woodall
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - John R. Harp
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - William T. Brewer
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Eric D. Tague
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Shawn R. Campagna
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
- Biological and Small Molecule Mass Spectrometry Core, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
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6
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Kurita K, Kato F, Shiomi D. Alteration of Membrane Fluidity or Phospholipid Composition Perturbs Rotation of MreB Complexes in Escherichia coli. Front Mol Biosci 2020; 7:582660. [PMID: 33330621 PMCID: PMC7719821 DOI: 10.3389/fmolb.2020.582660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/30/2020] [Indexed: 11/28/2022] Open
Abstract
Gram-negative bacteria such as Escherichia coli are surrounded by inner and outer membranes and peptidoglycan in between, protecting the cells from turgor pressure and maintaining cell shape. The Rod complex, which synthesizes peptidoglycan, is composed of various proteins such as a cytoplasmic protein MreB, a transmembrane protein RodZ, and a transpeptidase PBP2. The Rod complex is a highly motile complex that rotates around the long axis of a cell. Previously, we had reported that anionic phospholipids (aPLs; phosphatidylglycerol and cardiolipin) play a role in the localization of MreB. In this study, we identified that cells lacking aPLs slow down Rod complex movement. We also found that at higher temperatures, the speed of movement increased in cells lacking aPLs, suggesting that membrane fluidity is important for movement. Consistent with this idea, Rod complex motion was reduced, and complex formation was disturbed in the cells depleted of FabA or FabB, which are essential for unsaturated fatty acid synthesis. These cells also showed abnormal morphology. Therefore, membrane fluidity is important for maintaining cell shape through the regulation of Rod complex formation and motility.
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Affiliation(s)
| | | | - Daisuke Shiomi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
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7
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Induction of Daptomycin Tolerance in Enterococcus faecalis by Fatty Acid Combinations. Appl Environ Microbiol 2020; 86:AEM.01178-20. [PMID: 32801181 PMCID: PMC7531955 DOI: 10.1128/aem.01178-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/08/2020] [Indexed: 12/14/2022] Open
Abstract
With an increasing prevalence of antibiotic resistance in the clinic, we strive to understand more about microbial defensive mechanisms. A nongenetic tolerance to the antibiotic daptomycin was discovered in Enterococcus faecalis that results in the increased survival of bacterial populations after treatment with the drug. This tolerance mechanism likely synergizes with antibiotic resistance in the clinic. Given that this tolerance phenotype is induced by incorporation of fatty acids present in the host, it can be assumed that infections by this organism require a higher dose of antibiotic for successful eradication. The mixture of fatty acids in human fluids is quite diverse, with little understanding between the interplay of fatty acid combinations and the tolerance phenotype we observe. It is crucial to understand the effects of fatty acid combinations on E. faecalis physiology if we are to suppress the tolerance physiology in the clinic. Enterococcus faecalis is a Gram-positive bacterium that normally exists as an intestinal commensal in humans but is also a leading cause of nosocomial infections. Previous work noted that growth supplementation with serum induced tolerance to membrane-damaging agents, including the antibiotic daptomycin. Specific fatty acids found within serum could independently provide tolerance to daptomycin (protective fatty acids), yet some fatty acids found in serum did not and had negative effects on enterococcal physiology (nonprotective fatty acids). Here, we measured a wide array of physiological responses after supplementation with combinations of protective and nonprotective fatty acids to better understand how serum induces daptomycin tolerance. When cells were supplemented with either nonprotective fatty acid, palmitic acid, or stearic acid, there were marked defects in growth and morphology, but these defects were rescued upon supplementation with either protective fatty acid, oleic acid, or linoleic acid. Membrane fluidity decreased with growth in either palmitic or stearic acid alone but returned to basal levels when a protective fatty acid was supplied. Daptomycin tolerance could be induced if a protective fatty acid was provided with a nonprotective fatty acid, and some specific combinations protected as well as serum supplementation. While cell envelope charge has been associated with tolerance to daptomycin in other Gram-positive bacteria, we concluded that it does not correlate with the fatty acid-induced protection we observed. Based on these observations, we conclude that daptomycin tolerance by serum is driven by specific, protective fatty acids found within the fluid. IMPORTANCE With an increasing prevalence of antibiotic resistance in the clinic, we strive to understand more about microbial defensive mechanisms. A nongenetic tolerance to the antibiotic daptomycin was discovered in Enterococcus faecalis that results in the increased survival of bacterial populations after treatment with the drug. This tolerance mechanism likely synergizes with antibiotic resistance in the clinic. Given that this tolerance phenotype is induced by incorporation of fatty acids present in the host, it can be assumed that infections by this organism require a higher dose of antibiotic for successful eradication. The mixture of fatty acids in human fluids is quite diverse, with little understanding between the interplay of fatty acid combinations and the tolerance phenotype we observe. It is crucial to understand the effects of fatty acid combinations on E. faecalis physiology if we are to suppress the tolerance physiology in the clinic.
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8
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Furey PC, Lee SS, Clemans DL. Substratum-associated microbiota. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2020; 92:1629-1648. [PMID: 33463854 DOI: 10.1002/wer.1410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 06/12/2023]
Abstract
Highlights of new, interesting, and emerging research findings on substratum-associated microbiota covered from a survey of 2019 literature from primarily freshwaters provide insight into research trends of interest to the Water Environment Federation and others interested in benthic, aquatic environments. Coverage of topics on bottom-associated or attached algae and cyanobacteria, though not comprehensive, includes new methods, taxa new-to-science, nutrient dynamics, auto- and heterotrophic interactions, grazers, bioassessment, herbicides and other pollutants, metal contaminants, and nuisance, and bloom-forming and harmful algae. Coverage of bacteria, also not comprehensive, focuses on the ecology of benthic biofilms and microbial communities, along with the ecology of microbes like Caulobacter crescentus, Rhodobacter, and other freshwater microbial species. Bacterial topics covered also include metagenomics and metatranscriptomics, toxins and pollutants, bacterial pathogens and bacteriophages, and bacterial physiology. Readers may use this literature review to learn about or renew their interest in the recent advances and discoveries regarding substratum-associated microbiota. PRACTITIONER POINTS: This review of literature from 2019 on substratum-associated microbiota presents highlights of findings on algae, cyanobacteria, and bacteria from primarily freshwaters. Coverage of algae and cyanobacteria includes findings on new methods, taxa new to science, nutrient dynamics, auto- and heterotrophic interactions, grazers, bioassessment, herbicides and other pollutants, metal contaminants, and nuisance, bloom-forming and harmful algae. Coverage of bacteria includes findings on ecology of benthic biofilms and microbial communities, the ecology of microbes, metagenomics and metatranscriptomics, toxins and pollutants, bacterial pathogens and bacteriophages, and bacterial physiology. Highlights of new, noteworthy and emerging topics build on those from 2018 and will be of relevance to the Water Environment Federation and others interested in benthic, aquatic environments.
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Affiliation(s)
- Paula C Furey
- Department Biology, St. Catherine University, St. Paul, Minnesota, USA
| | - Sylvia S Lee
- Office of Research and Development, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Daniel L Clemans
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, USA
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9
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Si Chaib Z, Marchetto A, Dishnica K, Carloni P, Giorgetti A, Rossetti G. Impact of Cholesterol on the Stability of Monomeric and Dimeric Forms of the Translocator Protein TSPO: A Molecular Simulation Study. Molecules 2020; 25:molecules25184299. [PMID: 32961709 PMCID: PMC7570527 DOI: 10.3390/molecules25184299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 11/25/2022] Open
Abstract
The translocator protein (TSPO) is a transmembrane protein present across the three domains of life. Its functional quaternary structure consists of one or more subunits. In mice, the dimer-to-monomer equilibrium is shifted in vitro towards the monomer by adding cholesterol, a natural component of mammalian membranes. Here, we present a coarse-grained molecular dynamics study on the mouse protein in the presence of a physiological content and of an excess of cholesterol. The latter turns out to weaken the interfaces of the dimer by clusterizing mostly at the inter-monomeric space and pushing the contact residues apart. It also increases the compactness and the rigidity of the monomer. These two factors might play a role for the experimentally observed incremented stability of the monomeric form with increased content of cholesterol. Comparison with simulations on bacterial proteins suggests that the effect of cholesterol is much less pronounced for the latter than for the mouse protein.
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Affiliation(s)
- Zeineb Si Chaib
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, 52062 Aachen, Germany
| | - Alessandro Marchetto
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
| | - Klevia Dishnica
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
| | - Paolo Carloni
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, 52062 Aachen, Germany
- Institute for Neuroscience and Medicine (INM-11) “Molecular Neuroscience and Neuroimaging”, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Alejandro Giorgetti
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
- Correspondence: (A.G.); (G.R.)
| | - Giulia Rossetti
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Jülich Supercomputing Center (JSC), Forschungszentrum Jülich, 52425 Jülich, Germany
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation University Hospital Aachen, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
- Correspondence: (A.G.); (G.R.)
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10
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Probst AJ, Elling FJ, Castelle CJ, Zhu Q, Elvert M, Birarda G, Holman HYN, Lane KR, Ladd B, Ryan MC, Woyke T, Hinrichs KU, Banfield JF. Lipid analysis of CO 2-rich subsurface aquifers suggests an autotrophy-based deep biosphere with lysolipids enriched in CPR bacteria. ISME JOURNAL 2020; 14:1547-1560. [PMID: 32203118 PMCID: PMC7242380 DOI: 10.1038/s41396-020-0624-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/05/2020] [Accepted: 02/25/2020] [Indexed: 11/09/2022]
Abstract
Sediment-hosted CO2-rich aquifers deep below the Colorado Plateau (USA) contain a remarkable diversity of uncultivated microorganisms, including Candidate Phyla Radiation (CPR) bacteria that are putative symbionts unable to synthesize membrane lipids. The origin of organic carbon in these ecosystems is unknown and the source of CPR membrane lipids remains elusive. We collected cells from deep groundwater brought to the surface by eruptions of Crystal Geyser, sequenced the community, and analyzed the whole community lipidome over time. Characteristic stable carbon isotopic compositions of microbial lipids suggest that bacterial and archaeal CO2 fixation ongoing in the deep subsurface provides organic carbon for the complex communities that reside there. Coupled lipidomic-metagenomic analysis indicates that CPR bacteria lack complete lipid biosynthesis pathways but still possess regular lipid membranes. These lipids may therefore originate from other community members, which also adapt to high in situ pressure by increasing fatty acid unsaturation. An unusually high abundance of lysolipids attributed to CPR bacteria may represent an adaptation to membrane curvature stress induced by their small cell sizes. Our findings provide new insights into the carbon cycle in the deep subsurface and suggest the redistribution of lipids into putative symbionts within this community.
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Affiliation(s)
- Alexander J Probst
- Department of Earth and Planetary Science, University of California, Berkeley, CA, 94720, USA. .,Institute for Environmental Microbiology and Biotechnology, Department of Chemistry, University of Duisburg-Essen, Essen, Germany.
| | - Felix J Elling
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany. .,Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, 02138, USA.
| | - Cindy J Castelle
- Department of Earth and Planetary Science, University of California, Berkeley, CA, 94720, USA.,MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Qingzeng Zhu
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Marcus Elvert
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Giovanni Birarda
- Elettra-Sincrotrone Trieste, Strada Statale 14-km 163,5 Basovizza, 34149, Trieste, Italy.,Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Hoi-Ying N Holman
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Katherine R Lane
- Department of Earth and Planetary Science, University of California, Berkeley, CA, 94720, USA
| | - Bethany Ladd
- Department of Geoscience, University of Calgary, Calgary, AB, T2N 1N4, Canada.,Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - M Cathryn Ryan
- Department of Geoscience, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, MA, USA
| | - Kai-Uwe Hinrichs
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
| | - Jillian F Banfield
- Department of Earth and Planetary Science, University of California, Berkeley, CA, 94720, USA.
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