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  1. Article: A

    Panta, Pradip R / Doerrler, William T

    Frontiers in microbiology

    2021  Volume 11, Page(s) 618389

    Abstract: The DedA family is a conserved membrane protein family found in most organisms. ... ...

    Abstract The DedA family is a conserved membrane protein family found in most organisms. A
    Language English
    Publishing date 2021-01-12
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2587354-4
    ISSN 1664-302X
    ISSN 1664-302X
    DOI 10.3389/fmicb.2020.618389
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: A link between pH homeostasis and colistin resistance in bacteria.

    Panta, Pradip R / Doerrler, William T

    Scientific reports

    2021  Volume 11, Issue 1, Page(s) 13230

    Abstract: Colistin resistance is complex and multifactorial. DbcA is an inner membrane protein belonging to the DedA superfamily required for maintaining extreme colistin resistance of Burkholderia thailandensis. The molecular mechanisms behind this remain unclear. ...

    Abstract Colistin resistance is complex and multifactorial. DbcA is an inner membrane protein belonging to the DedA superfamily required for maintaining extreme colistin resistance of Burkholderia thailandensis. The molecular mechanisms behind this remain unclear. Here, we report that ∆dbcA displays alkaline pH/bicarbonate sensitivity and propose a role of DbcA in extreme colistin resistance of B. thailandensis by maintaining cytoplasmic pH homeostasis. We found that alkaline pH or presence of sodium bicarbonate displays a synergistic effect with colistin against not only extremely colistin resistant species like B. thailandensis and Serratia marcescens, but also a majority of Gram-negative and Gram-positive bacteria tested, suggesting a link between cytoplasmic pH homeostasis and colistin resistance across species. We found that lowering the level of oxygen in the growth media or supplementation of fermentable sugars such as glucose not only alleviated alkaline pH stress, but also increased colistin resistance in most bacteria tested, likely by avoiding cytoplasmic alkalinization. Our observations suggest a previously unreported link between pH, oxygen, and colistin resistance. We propose that maintaining optimal cytoplasmic pH is required for colistin resistance in a majority of bacterial species, consistent with the emerging link between cytoplasmic pH homeostasis and antibiotic resistance.
    MeSH term(s) Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/drug effects ; Bacterial Proteins/metabolism ; Burkholderia/drug effects ; Burkholderia/physiology ; Colistin/pharmacology ; Culture Media/metabolism ; Drug Resistance, Bacterial/drug effects ; Drug Resistance, Bacterial/physiology ; Homeostasis/physiology ; Hydrogen-Ion Concentration ; Membrane Proteins/metabolism ; Microbial Sensitivity Tests ; Serratia marcescens/drug effects ; Serratia marcescens/physiology
    Chemical Substances Anti-Bacterial Agents ; Bacterial Proteins ; Culture Media ; Membrane Proteins ; Colistin (Z67X93HJG1)
    Language English
    Publishing date 2021-06-24
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-021-92718-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Klebsiella pneumoniae

    Tiwari, Vijay / Sharma, Amit / Braga, Reygan / Garcia, Emily / Appiah, Ridhwana / Fleeman, Renee / Abuaita, Basel H / Patrauchan, Marianna / Doerrler, William T

    Microbiology spectrum

    2024  Volume 12, Issue 2, Page(s) e0380723

    Abstract: The DedA superfamily is a highly conserved family of membrane proteins. Deletion ... ...

    Abstract The DedA superfamily is a highly conserved family of membrane proteins. Deletion of
    MeSH term(s) Humans ; Escherichia coli/genetics ; Escherichia coli Proteins/genetics ; Klebsiella pneumoniae/metabolism ; Cations, Divalent/metabolism ; Calcium/metabolism ; Edetic Acid ; Phagocytosis ; Homeostasis ; Amino Acids/metabolism ; Anti-Bacterial Agents/metabolism ; Klebsiella Infections ; Bacterial Proteins/genetics
    Chemical Substances Escherichia coli Proteins ; Cations, Divalent ; Calcium (SY7Q814VUP) ; Edetic Acid (9G34HU7RV0) ; Amino Acids ; Anti-Bacterial Agents ; Bacterial Proteins
    Language English
    Publishing date 2024-01-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2807133-5
    ISSN 2165-0497 ; 2165-0497
    ISSN (online) 2165-0497
    ISSN 2165-0497
    DOI 10.1128/spectrum.03807-23
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Transcription Factor PecS Mediates

    Nwokocha, George C / Adhikari, Prava / Iqbal, Asif / Elkholy, Hannah / Doerrler, William T / Larkin, John C / Grove, Anne

    Journal of bacteriology

    2023  Volume 205, Issue 7, Page(s) e0047822

    Abstract: The transcriptional regulator PecS is encoded by select bacterial pathogens. For instance, in the plant pathogen Dickeya dadantii, PecS controls a range of virulence genes, including pectinase genes and the divergently oriented ... ...

    Abstract The transcriptional regulator PecS is encoded by select bacterial pathogens. For instance, in the plant pathogen Dickeya dadantii, PecS controls a range of virulence genes, including pectinase genes and the divergently oriented gene
    MeSH term(s) Transcription Factors/genetics ; Reactive Oxygen Species ; Gene Expression Regulation, Bacterial ; Agrobacterium/genetics ; Agrobacterium tumefaciens/metabolism ; Bacterial Proteins/genetics
    Chemical Substances Transcription Factors ; Reactive Oxygen Species ; Bacterial Proteins
    Language English
    Publishing date 2023-06-14
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2968-3
    ISSN 1098-5530 ; 0021-9193
    ISSN (online) 1098-5530
    ISSN 0021-9193
    DOI 10.1128/jb.00478-22
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: A link between pH homeostasis and colistin resistance in bacteria

    Pradip R. Panta / William T. Doerrler

    Scientific Reports, Vol 11, Iss 1, Pp 1-

    2021  Volume 16

    Abstract: Abstract Colistin resistance is complex and multifactorial. DbcA is an inner membrane protein belonging to the DedA superfamily required for maintaining extreme colistin resistance of Burkholderia thailandensis. The molecular mechanisms behind this ... ...

    Abstract Abstract Colistin resistance is complex and multifactorial. DbcA is an inner membrane protein belonging to the DedA superfamily required for maintaining extreme colistin resistance of Burkholderia thailandensis. The molecular mechanisms behind this remain unclear. Here, we report that ∆dbcA displays alkaline pH/bicarbonate sensitivity and propose a role of DbcA in extreme colistin resistance of B. thailandensis by maintaining cytoplasmic pH homeostasis. We found that alkaline pH or presence of sodium bicarbonate displays a synergistic effect with colistin against not only extremely colistin resistant species like B. thailandensis and Serratia marcescens, but also a majority of Gram-negative and Gram-positive bacteria tested, suggesting a link between cytoplasmic pH homeostasis and colistin resistance across species. We found that lowering the level of oxygen in the growth media or supplementation of fermentable sugars such as glucose not only alleviated alkaline pH stress, but also increased colistin resistance in most bacteria tested, likely by avoiding cytoplasmic alkalinization. Our observations suggest a previously unreported link between pH, oxygen, and colistin resistance. We propose that maintaining optimal cytoplasmic pH is required for colistin resistance in a majority of bacterial species, consistent with the emerging link between cytoplasmic pH homeostasis and antibiotic resistance.
    Keywords Medicine ; R ; Science ; Q
    Subject code 571
    Language English
    Publishing date 2021-06-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: A membrane protein of the rice pathogen Burkholderia glumae required for oxalic acid secretion and quorum sensing.

    Iqbal, Asif / Nwokocha, George / Tiwari, Vijay / Barphagha, Inderjit K / Grove, Anne / Ham, Jong Hyun / Doerrler, William T

    Molecular plant pathology

    2023  Volume 24, Issue 11, Page(s) 1400–1413

    Abstract: Bacterial panicle blight is caused by Burkholderia glumae and results in damage to rice crops worldwide. Virulence of B. glumae requires quorum sensing (QS)-dependent synthesis and export of toxoflavin, responsible for much of the damage to rice. The ... ...

    Abstract Bacterial panicle blight is caused by Burkholderia glumae and results in damage to rice crops worldwide. Virulence of B. glumae requires quorum sensing (QS)-dependent synthesis and export of toxoflavin, responsible for much of the damage to rice. The DedA family is a conserved membrane protein family found in all bacterial species. B. glumae possesses a member of the DedA family, named DbcA, which we previously showed is required for toxoflavin secretion and virulence in a rice model of infection. B. glumae secretes oxalic acid as a "common good" in a QS-dependent manner to combat toxic alkalinization of the growth medium during the stationary phase. Here, we show that B. glumae ΔdbcA fails to secrete oxalic acid, leading to alkaline toxicity and sensitivity to divalent cations, suggesting a role for DbcA in oxalic acid secretion. B. glumae ΔdbcA accumulated less acyl-homoserine lactone (AHL) QS signalling molecules as the bacteria entered the stationary phase, probably due to nonenzymatic inactivation of AHL at alkaline pH. Transcription of toxoflavin and oxalic acid operons was down-regulated in ΔdbcA. Alteration of the proton motive force with sodium bicarbonate also reduced oxalic acid secretion and expression of QS-dependent genes. Overall, the data show that DbcA is required for oxalic acid secretion in a proton motive force-dependent manner, which is critical for QS of B. glumae. Moreover, this study supports the idea that sodium bicarbonate may serve as a chemical for treatment of bacterial panicle blight.
    MeSH term(s) Oryza/microbiology ; Quorum Sensing ; Membrane Proteins/metabolism ; Sodium Bicarbonate/metabolism ; Burkholderia/genetics ; Oxalic Acid/metabolism ; Bacterial Proteins/metabolism
    Chemical Substances Membrane Proteins ; Sodium Bicarbonate (8MDF5V39QO) ; Oxalic Acid (9E7R5L6H31) ; Bacterial Proteins
    Language English
    Publishing date 2023-07-10
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2020755-4
    ISSN 1364-3703 ; 1364-3703
    ISSN (online) 1364-3703
    ISSN 1364-3703
    DOI 10.1111/mpp.13376
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Chemical or Genetic Alteration of Proton Motive Force Results in Loss of Virulence of Burkholderia glumae, the Cause of Rice Bacterial Panicle Blight.

    Iqbal, Asif / Panta, Pradip R / Ontoy, John / Bruno, Jobelle / Ham, Jong Hyun / Doerrler, William T

    Applied and environmental microbiology

    2021  Volume 87, Issue 18, Page(s) e0091521

    Abstract: Rice is an important source of food for more than half of the world's population. Bacterial panicle blight (BPB) is a disease of rice characterized by grain discoloration or sheath rot caused mainly by Burkholderia glumae. B. glumae synthesizes ... ...

    Abstract Rice is an important source of food for more than half of the world's population. Bacterial panicle blight (BPB) is a disease of rice characterized by grain discoloration or sheath rot caused mainly by Burkholderia glumae. B. glumae synthesizes toxoflavin, an essential virulence factor that is required for symptoms of the disease. The products of the
    MeSH term(s) Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Burkholderia/drug effects ; Burkholderia/genetics ; Burkholderia/metabolism ; Burkholderia/pathogenicity ; Carbonyl Cyanide m-Chlorophenyl Hydrazone/pharmacology ; Onions/microbiology ; Oryza/microbiology ; Plant Diseases/microbiology ; Proton-Motive Force ; Pyrimidinones/metabolism ; Sodium Bicarbonate/pharmacology ; Triazines/metabolism ; Virulence ; Virulence Factors/metabolism
    Chemical Substances Anti-Bacterial Agents ; Bacterial Proteins ; Pyrimidinones ; Triazines ; Virulence Factors ; Carbonyl Cyanide m-Chlorophenyl Hydrazone (555-60-2) ; toxoflavin (5N5YI4IP1P) ; Sodium Bicarbonate (8MDF5V39QO)
    Language English
    Publishing date 2021-08-26
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 223011-2
    ISSN 1098-5336 ; 0099-2240
    ISSN (online) 1098-5336
    ISSN 0099-2240
    DOI 10.1128/AEM.00915-21
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  8. Article ; Online: Escherichia coli YqjA, a Member of the Conserved DedA/Tvp38 Membrane Protein Family, Is a Putative Osmosensing Transporter Required for Growth at Alkaline pH.

    Kumar, Sujeet / Doerrler, William T

    Journal of bacteriology

    2015  Volume 197, Issue 14, Page(s) 2292–2300

    Abstract: Unlabelled: The ability to persist and grow under alkaline conditions is an important characteristic of many bacteria. In order to survive at alkaline pH, Escherichia coli must maintain a stable cytoplasmic pH of about 7.6. Membrane cation/proton ... ...

    Abstract Unlabelled: The ability to persist and grow under alkaline conditions is an important characteristic of many bacteria. In order to survive at alkaline pH, Escherichia coli must maintain a stable cytoplasmic pH of about 7.6. Membrane cation/proton antiporters play a major role in alkaline pH homeostasis by catalyzing active inward proton transport. The DedA/Tvp38 family is a highly conserved membrane protein family of unknown function present in most sequenced genomes. YqjA and YghB are members of the E. coli DedA family with 62% amino acid identity and partially redundant functions. We have shown that E. coli with ΔyqjA and ΔyghB mutations cannot properly maintain the proton motive force (PMF) and is compromised in PMF-dependent drug efflux and other PMF-dependent functions. Furthermore, the functions of YqjA and YghB are dependent upon membrane-embedded acidic amino acids, a hallmark of several families of proton-dependent transporters. Here, we show that the ΔyqjA mutant (but not ΔyghB) cannot grow under alkaline conditions (ranging from pH 8.5 to 9.5), unlike the parent E. coli. Overexpression of yqjA restores growth at alkaline pH, but only when more than ∼100 mM sodium or potassium is present in the growth medium. Increasing the osmotic pressure by the addition of sucrose enhances the ability of YqjA to support growth under alkaline conditions in the presence of low salt concentrations, consistent with YqjA functioning as an osmosensor. We suggest that YqjA possesses proton-dependent transport activity that is stimulated by osmolarity and that it plays a significant role in the survival of E. coli at alkaline pH.
    Importance: The ability to survive under alkaline conditions is important for many species of bacteria. Escherichia coli can grow at pH 5.5 to 9.5 while maintaining a constant cytoplasmic pH of about 7.6. Under alkaline conditions, bacteria rely upon proton-dependent transporters to maintain a constant cytoplasmic pH. The DedA/Tvp38 protein family is a highly conserved but poorly characterized family of membrane proteins. Here, we show that the DedA/Tvp38 protein YqjA is critical for E. coli to survive at pH 8.5 to 9.5. YqjA requires sodium and potassium for this function. At low cation concentrations, osmolytes, including sucrose, can facilitate rescue of E. coli growth by YqjA at high pH. These data are consistent with YqjA functioning as an osmosensing cation-dependent proton transporter.
    MeSH term(s) Carrier Proteins/genetics ; Carrier Proteins/metabolism ; Culture Media/chemistry ; Escherichia coli/genetics ; Escherichia coli/metabolism ; Escherichia coli Proteins/genetics ; Escherichia coli Proteins/metabolism ; Gene Expression Regulation, Bacterial/physiology ; Hydrogen-Ion Concentration ; Membrane Proteins/genetics ; Membrane Proteins/metabolism ; Mutation ; Plasmids
    Chemical Substances Carrier Proteins ; Culture Media ; Escherichia coli Proteins ; Membrane Proteins ; YqjA protein, E coli
    Language English
    Publishing date 2015-07
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2968-3
    ISSN 1098-5530 ; 0021-9193
    ISSN (online) 1098-5530
    ISSN 0021-9193
    DOI 10.1128/JB.00175-15
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Cpx-dependent expression of YqjA requires cations at elevated pH.

    Kumar, Sujeet / Tiwari, Vijay / Doerrler, William T

    FEMS microbiology letters

    2017  Volume 364, Issue 12

    Abstract: Under alkaline pH conditions, Escherichia coli must maintain a stable cytoplasmic pH of about 7.6 that is acidic relative to the environment. Bacteria employ various mechanisms to survive alkaline pH; however, membrane cation/H+ antiporters play a ... ...

    Abstract Under alkaline pH conditions, Escherichia coli must maintain a stable cytoplasmic pH of about 7.6 that is acidic relative to the environment. Bacteria employ various mechanisms to survive alkaline pH; however, membrane cation/H+ antiporters play a primary role by facilitating inward transport of protons. Escherichia coli YqjA belongs to the DedA/Tvp38 membrane protein family and, along with its paralog YghB, is required for growth at 42°C, proper cell division and antibiotic resistance. YqjA is required for viability at alkaline pH, requiring cations sodium or potassium to support growth under these conditions, suggesting it may be a transporter. We measured yqjA expression at different pHs and cation concentrations using a yqjA promoter-lacZ fusion. We found that yqjA promoter activity was highest at alkaline pH. Increased activity of the yqjA promoter required both the transcriptional regulator CpxR, in agreement with previous results, and sodium or potassium salts at alkaline pH. Extracellular cations are also required for activity of cpxP and degP promoters at alkaline pH, suggesting this is a general property of the Cpx regulon. To our knowledge, this is the first demonstration of cation-dependent expression of Cpx-regulated genes at alkaline pH.
    MeSH term(s) Antiporters/genetics ; Bacterial Proteins/genetics ; Cations, Monovalent ; Escherichia coli/genetics ; Escherichia coli/growth & development ; Escherichia coli Proteins/genetics ; Gene Expression Regulation, Bacterial ; Hydrogen-Ion Concentration ; Lac Operon ; Membrane Proteins/genetics ; Membrane Transport Proteins/genetics ; Membrane Transport Proteins/metabolism ; Mutation ; Potassium/chemistry ; Promoter Regions, Genetic ; Regulon ; Sodium/chemistry
    Chemical Substances Antiporters ; Bacterial Proteins ; Cations, Monovalent ; Escherichia coli Proteins ; Membrane Proteins ; Membrane Transport Proteins ; YqjA protein, E coli ; CpxR protein, Bacteria (153554-07-5) ; Sodium (9NEZ333N27) ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2017-06-06
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 752343-9
    ISSN 1574-6968 ; 0378-1097
    ISSN (online) 1574-6968
    ISSN 0378-1097
    DOI 10.1093/femsle/fnx115
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: A Klebsiella pneumoniae DedA family membrane protein is required for colistin resistance and for virulence in wax moth larvae.

    Tiwari, Vijay / Panta, Pradip R / Billiot, Caitlin E / Douglass, Martin V / Herrera, Carmen M / Trent, M Stephen / Doerrler, William T

    Scientific reports

    2021  Volume 11, Issue 1, Page(s) 24365

    Abstract: Ineffectiveness of carbapenems against multidrug resistant pathogens led to the increased use of colistin (polymyxin E) as a last resort antibiotic. A gene belonging to the DedA family encoding conserved membrane proteins was previously identified by ... ...

    Abstract Ineffectiveness of carbapenems against multidrug resistant pathogens led to the increased use of colistin (polymyxin E) as a last resort antibiotic. A gene belonging to the DedA family encoding conserved membrane proteins was previously identified by screening a transposon library of K. pneumoniae ST258 for sensitivity to colistin. We have renamed this gene dkcA (dedA of Klebsiella required for colistin resistance). DedA family proteins are likely membrane transporters required for viability of Escherichia coli and Burkholderia spp. at alkaline pH and for resistance to colistin in a number of bacterial species. Colistin resistance is often conferred via modification of the lipid A component of bacterial lipopolysaccharide with aminoarabinose (Ara4N) and/or phosphoethanolamine. Mass spectrometry analysis of lipid A of the ∆dkcA mutant shows a near absence of Ara4N in the lipid A, suggesting a requirement for DkcA for lipid A modification with Ara4N. Mutation of K. pneumoniae dkcA resulted in a reduction of the colistin minimal inhibitory concentration to approximately what is found with a ΔarnT strain. We also identify a requirement of DkcA for colistin resistance that is independent of lipid A modification, instead requiring maintenance of optimal membrane potential. K. pneumoniae ΔdkcA displays reduced virulence in Galleria mellonella suggesting colistin sensitivity can cause loss of virulence.
    MeSH term(s) Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Colistin/pharmacology ; Drug Resistance, Bacterial ; Klebsiella Infections/drug therapy ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/drug effects ; Klebsiella pneumoniae/isolation & purification ; Larva/drug effects ; Larva/growth & development ; Larva/microbiology ; Membrane Proteins ; Moths/drug effects ; Moths/growth & development ; Moths/microbiology ; Virulence
    Chemical Substances Anti-Bacterial Agents ; Bacterial Proteins ; Membrane Proteins ; Colistin (Z67X93HJG1)
    Language English
    Publishing date 2021-12-21
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-021-03834-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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