1
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Wang C, Gamage PL, Jiang W, Mudalige T. Excipient-related impurities in liposome drug products. Int J Pharm 2024; 657:124164. [PMID: 38688429 DOI: 10.1016/j.ijpharm.2024.124164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
Liposomes are widely used in the pharmaceutical industry as drug delivery systems to increase the efficacy and reduce the off-target toxicity of active pharmaceutical ingredients (APIs). The liposomes are more complex drug delivery systems than the traditional dosage forms, and phospholipids and cholesterol are the major structural excipients. These two excipients undergo hydrolysis and/or oxidation during liposome preparation and storage, resulting in lipids hydrolyzed products (LHPs) and cholesterol oxidation products (COPs) in the final liposomal formulations. These excipient-related impurities at elevated concentrations may affect liposome stability and exert biological functions. This review focuses on LHPs and COPs, two major categories of excipient-related impurities in the liposomal formulations, and discusses factors affecting their formation, and analytical methods to determine these excipient-related impurities.
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Affiliation(s)
- Changguang Wang
- Arkansas Laboratory, Office of Regulatory Affairs, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Prabhath L Gamage
- Arkansas Laboratory, Office of Regulatory Affairs, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Wenlei Jiang
- Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, 20993, USA.
| | - Thilak Mudalige
- Arkansas Laboratory, Office of Regulatory Affairs, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA.
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2
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Bogdanov M. Renovating a double fence with or without notifying the next door and across the street neighbors: why the biogenic cytoplasmic membrane of Gram-negative bacteria display asymmetry? Emerg Top Life Sci 2023; 7:137-150. [PMID: 36960750 PMCID: PMC10725183 DOI: 10.1042/etls20230042] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 03/03/2023] [Accepted: 03/13/2023] [Indexed: 03/25/2023]
Abstract
The complex two-membrane organization of the envelope of Gram-negative bacteria imposes an unique biosynthetic and topological constraints that can affect translocation of lipids and proteins synthesized on the cytoplasm facing leaflet of the cytoplasmic (inner) membrane (IM), across the IM and between the IM and outer membrane (OM). Balanced growth of two membranes and continuous loss of phospholipids in the periplasmic leaflet of the IM as metabolic precursors for envelope components and for translocation to the OM requires a constant supply of phospholipids in the IM cytosolic leaflet. At present we have no explanation as to why the biogenic E. coli IM displays asymmetry. Lipid asymmetry is largely related to highly entropically disfavored, unequal headgroup and acyl group asymmetries which are usually actively maintained by active mechanisms. However, these mechanisms are largely unknown for bacteria. Alternatively, lipid asymmetry in biogenic IM could be metabolically controlled in order to maintain uniform bilayer growth and asymmetric transmembrane arrangement by balancing temporally the net rates of synthesis and flip-flop, inter IM and OM bidirectional flows and bilayer chemical and physical properties as spontaneous response. Does such flippase-less or 'lipid only", 'passive' mechanism of generation and maintenance of lipid asymmetry exists in the IM? The driving force for IM asymmetry can arise from the packing requirements imposed upon the bilayer system during cell division through disproportional distribution of two negatively curved phospholipids, phosphatidylethanolamine and cardiolipin, with consistent reciprocal tendency to increase and decrease lipid order in each membrane leaflet respectively.
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Affiliation(s)
- Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, U.S.A
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3
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Cao X, van Putten JPM, Wösten MMSM. Biological functions of bacterial lysophospholipids. Adv Microb Physiol 2023; 82:129-154. [PMID: 36948653 DOI: 10.1016/bs.ampbs.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Lysophospholipids (LPLs) are lipid-derived metabolic intermediates in the cell membrane. The biological functions of LPLs are distinct from their corresponding phospholipids. In eukaryotic cells LPLs are important bioactive signaling molecules that regulate many important biological processes, but in bacteria the function of LPLs is still not fully defined. Bacterial LPLs are usually present in cells in very small amounts, but can strongly increase under certain environmental conditions. In addition to their basic function as precursors in membrane lipid metabolism, the formation of distinct LPLs contributes to the proliferation of bacteria under harsh circumstances or may act as signaling molecules in bacterial pathogenesis. This review provides an overview of the current knowledge of the biological functions of bacterial LPLs including lysoPE, lysoPA, lysoPC, lysoPG, lysoPS and lysoPI in bacterial adaptation, survival, and host-microbe interactions.
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Affiliation(s)
- Xuefeng Cao
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, The Netherlands
| | - Jos P M van Putten
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, The Netherlands
| | - Marc M S M Wösten
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, The Netherlands.
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4
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Ramos-Martín F, D'Amelio N. Biomembrane lipids: When physics and chemistry join to shape biological activity. Biochimie 2022; 203:118-138. [PMID: 35926681 DOI: 10.1016/j.biochi.2022.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/13/2022] [Accepted: 07/21/2022] [Indexed: 11/02/2022]
Abstract
Biomembranes constitute the first lines of defense of cells. While small molecules can often permeate cell walls in bacteria and plants, they are generally unable to penetrate the barrier constituted by the double layer of phospholipids, unless specific receptors or channels are present. Antimicrobial or cell-penetrating peptides are in fact highly specialized molecules able to bypass this barrier and even discriminate among different cell types. This capacity is made possible by the intrinsic properties of its phospholipids, their distribution between the internal and external leaflet, and their ability to mutually interact, modulating the membrane fluidity and the exposition of key headgroups. Although common phospholipids can be found in the membranes of most organisms, some are characteristic of specific cell types. Here, we review the properties of the most common lipids and describe how they interact with each other in biomembrane. We then discuss how their assembly in bilayers determines some key physical-chemical properties such as permeability, potential and phase status. Finally, we describe how the exposition of specific phospholipids determines the recognition of cell types by membrane-targeting molecules.
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Affiliation(s)
- Francisco Ramos-Martín
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, Amiens, 80039, France.
| | - Nicola D'Amelio
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, Amiens, 80039, France.
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5
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Kleetz J, Vasilopoulos G, Czolkoss S, Aktas M, Narberhaus F. Recombinant and endogenous ways to produce methylated phospholipids in Escherichia coli. Appl Microbiol Biotechnol 2021; 105:8837-8851. [PMID: 34709431 PMCID: PMC8590670 DOI: 10.1007/s00253-021-11654-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 10/31/2022]
Abstract
Escherichia coli is the daily workhorse in molecular biology research labs and an important platform microorganism in white biotechnology. Its cytoplasmic membrane is primarily composed of the phospholipids phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CL). As in most other bacteria, the typical eukaryotic phosphatidylcholine (PC) is not a regular component of the E. coli membrane. PC is known to act as a substrate in various metabolic or catabolic reactions, to affect protein folding and membrane insertion, and to activate proteins that originate from eukaryotic environments. Options to manipulate the E. coli membrane to include non-native lipids such as PC might make it an even more powerful and versatile tool for biotechnology and protein biochemistry. This article outlines different strategies how E. coli can be engineered to produce PC and other methylated PE derivatives. Several of these approaches rely on the ectopic expression of genes from natural PC-producing organisms. These include PC synthases, lysolipid acyltransferases, and several phospholipid N-methyltransferases with diverse substrate and product preferences. In addition, we show that E. coli has the capacity to produce PC by its own enzyme repertoire provided that appropriate precursors are supplied. Screening of the E. coli Keio knockout collection revealed the lysophospholipid transporter LplT to be responsible for the uptake of lyso-PC, which is then further acylated to PC by the acyltransferase-acyl carrier protein synthetase Aas. Overall, our study shows that the membrane composition of the most routinely used model bacterium can readily be tailored on demand.Key points• Escherichia coli can be engineered to produce non-native methylated PE derivatives.• These lipids can be produced by foreign and endogenous proteins.• Modification of E. coli membrane offers potential for biotechnology and research.
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Affiliation(s)
- Julia Kleetz
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Georgios Vasilopoulos
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Simon Czolkoss
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Meriyem Aktas
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Franz Narberhaus
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.
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6
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Czolkoss S, Borgert P, Poppenga T, Hölzl G, Aktas M, Narberhaus F. Synthesis of the unusual lipid bis(monoacylglycero)phosphate in environmental bacteria. Environ Microbiol 2021; 23:6993-7008. [PMID: 34528360 DOI: 10.1111/1462-2920.15777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 01/05/2023]
Abstract
The bacterial membrane is constantly remodelled in response to environmental conditions and the external supply of precursor molecules. Some bacteria are able to acquire exogenous lyso-phospholipids and convert them to the corresponding phospholipids. Here, we report that some soil-dwelling bacteria have alternative options to metabolize lyso-phosphatidylglycerol (L-PG). We find that the plant-pathogen Agrobacterium tumefaciens takes up this mono-acylated phospholipid and converts it to two distinct isoforms of the non-canonical lipid bis(monoacylglycero)phosphate (BMP). Chromatographic separation and quadrupole-time-of-flight MS/MS analysis revealed the presence of two possible BMP stereo configurations acylated at either of the free hydroxyl groups of the glycerol head group. BMP accumulated in the inner membrane and did not visibly alter cell morphology and growth behaviour. The plant-associated bacterium Sinorhizobium meliloti was also able to convert externally provided L-PG to BMP. Other bacteria like Pseudomonas fluorescens and Escherichia coli metabolized L-PG after cell disruption, suggesting that BMP production in the natural habitat relies both on dedicated uptake systems and on head-group acylation enzymes. Overall, our study adds two previously overlooked phospholipids to the repertoire of bacterial membrane lipids and provides evidence for the remarkable condition-responsive adaptation of bacterial membranes.
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Affiliation(s)
- Simon Czolkoss
- Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Pia Borgert
- Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Tessa Poppenga
- Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Georg Hölzl
- Institute of Molecular Physiology and Biotechnology of Plants (IMBIO), University of Bonn, Karlrobert-Kreiten-Straße 13, 53115 Bonn, Germany
| | - Meriyem Aktas
- Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Franz Narberhaus
- Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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7
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Cao X, Brouwers JFHM, van Dijk L, van de Lest CHA, Parker CT, Huynh S, van Putten JPM, Kelly DJ, Wösten MMSM. The Unique Phospholipidome of the Enteric Pathogen Campylobacter jejuni: Lysophosholipids Are Required for Motility at Low Oxygen Availability. J Mol Biol 2020; 432:5244-5258. [PMID: 32710984 DOI: 10.1016/j.jmb.2020.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/14/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022]
Abstract
In response to changes in their environment bacteria need to change both their protein and phospholipid repertoire to match environmental requirements, but the dynamics of bacterial phospholipid composition under different growth conditions is still largely unknown. In the present study, we investigated the phospholipidome of the bacterial pathogen Campylobacter jejuni. Transcription profiling on logarithmic and stationary phase grown cells of the microaerophilic human pathogen C. jejuni using RNA-seq revealed differential expression of putative phospholipid biosynthesis genes. By applying high-performance liquid chromatography tandem-mass spectrometry, we identified 203 phospholipid species representing the first determination of the phospholipidome of this pathogen. We identified nine different phospholipid classes carrying between one and three acyl chains. Phospholipidome analysis on bacteria of different ages (0-5 days) showed rapid changes in the ratio of phospholipids containing ethanolamine, or glycerol as phospholipid head group and in the number of cyclopropane bond containing fatty acids. Oxygen concentration influenced the percentage of lysophospholipids, and cyclo-propane bonds containing acyl chains. We show that large amounts of the phospholipids are lysophospholipids (30-45%), which mutant studies reveal are needed for normal C. jejuni motility at low oxygen conditions. C. jejuni possesses an unusual phospholipidome that is highly dynamic in response to environmental changes.
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Affiliation(s)
- Xuefeng Cao
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - Jos F H M Brouwers
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - Linda van Dijk
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - Chris H A van de Lest
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - Craig T Parker
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA 94710, USA
| | - Steven Huynh
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA 94710, USA
| | - Jos P M van Putten
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - David J Kelly
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Marc M S M Wösten
- Department Biomolecular Health Sciences, Utrecht University, Utrecht, the Netherlands.
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8
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Outer Membrane Lipid Secretion and the Innate Immune Response to Gram-Negative Bacteria. Infect Immun 2020; 88:IAI.00920-19. [PMID: 32253250 DOI: 10.1128/iai.00920-19] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria is an asymmetric lipid bilayer that consists of inner leaflet phospholipids and outer leaflet lipopolysaccharides (LPS). The asymmetric character and unique biochemistry of LPS molecules contribute to the OM's ability to function as a molecular permeability barrier that protects the bacterium against hazards in the environment. Assembly and regulation of the OM have been extensively studied for understanding mechanisms of antibiotic resistance and bacterial defense against host immunity; however, there is little knowledge on how Gram-negative bacteria release their OMs into their environment to manipulate their hosts. Discoveries in bacterial lipid trafficking, OM lipid homeostasis, and host recognition of microbial patterns have shed new light on how microbes secrete OM vesicles (OMVs) to influence inflammation, cell death, and disease pathogenesis. Pathogens release OMVs that contain phospholipids, like cardiolipins, and components of LPS molecules, like lipid A endotoxins. These multiacylated lipid amphiphiles are molecular patterns that are differentially detected by host receptors like the Toll-like receptor 4/myeloid differentiation factor 2 complex (TLR4/MD-2), mouse caspase-11, and human caspases 4 and 5. We discuss how lipid ligands on OMVs engage these pattern recognition receptors on the membranes and in the cytosol of mammalian cells. We then detail how bacteria regulate OM lipid asymmetry, negative membrane curvature, and the phospholipid-to-LPS ratio to control OMV formation. The goal is to highlight intersections between OM lipid regulation and host immunity and to provide working models for how bacterial lipids influence vesicle formation.
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9
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Buszewski B, Rogowska A, Railean-Plugaru V, Złoch M, Walczak-Skierska J, Pomastowski P. The Influence of Different Forms of Silver on Selected Pathogenic Bacteria. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E2403. [PMID: 32456144 PMCID: PMC7287713 DOI: 10.3390/ma13102403] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 01/24/2023]
Abstract
The application of silver nanoparticles as an antibacterial agent is becoming more common. Unfortunately, their effect on microorganisms is still not fully understood. Therefore, this paper attempts to investigate the influence of silver ions, biologically synthesized silver nanoparticles and nanoparticles functionalized with antibiotics on molecular bacteria profiles. The initial stage of research was aimed at the mechanism determination involved in antibiotics sorption onto nanoparticles' surface. For this purpose, the kinetics study was performed. Next, the functionalized formulations were characterized by Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and a zeta potential study. The results reveal that functionalization is a complex process, but does not significantly affect the stability of biocolloids. Furthermore, the antimicrobial assays, in most cases, have shown no increases in antibacterial activity after nanoparticle functionalization, which suggests that the functionalization process does not always generate the improved antimicrobial effect. Finally, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) technique was employed to characterize the changes in the molecular profile of bacteria treated with various antibacterial agents. The recorded spectra proved many differences in bacterial lipids and proteins profiles compared to untreated cells. In addition, the statistical analysis of recorded spectra revealed the strain-dependent nature of stress factors on the molecular profile of microorganisms.
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Affiliation(s)
- Bogusław Buszewski
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Wileńska 4, 87-100 Torun, Poland; (B.B.); (A.R.); (V.R.-P.); (M.Z.)
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland;
| | - Agnieszka Rogowska
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Wileńska 4, 87-100 Torun, Poland; (B.B.); (A.R.); (V.R.-P.); (M.Z.)
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland;
| | - Viorica Railean-Plugaru
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Wileńska 4, 87-100 Torun, Poland; (B.B.); (A.R.); (V.R.-P.); (M.Z.)
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland;
| | - Michał Złoch
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Wileńska 4, 87-100 Torun, Poland; (B.B.); (A.R.); (V.R.-P.); (M.Z.)
| | - Justyna Walczak-Skierska
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland;
| | - Paweł Pomastowski
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Wileńska 4, 87-100 Torun, Poland; (B.B.); (A.R.); (V.R.-P.); (M.Z.)
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10
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Lin Y, Zheng L, Bogdanov M. Measurement of Lysophospholipid Transport Across the Membrane Using Escherichia coli Spheroplasts. Methods Mol Biol 2019; 1949:165-180. [PMID: 30790256 DOI: 10.1007/978-1-4939-9136-5_13] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
In the inner membrane of Gram-negative bacteria lysophospholipid transporter (LplT) and the bifunctional acyl-acyl carrier protein (ACP) synthetase/2-acylglycerolphosphoethanolamine acyltransferase (Aas) form a glycerophospholipid remodeling system, which is capable of facilitating rapid retrograde translocation of lyso forms of phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin across the cytoplasmic membrane. This coupled remodeling enzyme tandem provides an effective method for the measurement of substrate specificity of the lipid regeneration and lysophospholipid transport per se across the membrane. This chapter describes two distinct but complementary methods for the measurement of lysophospholipid transport across membrane using Escherichia coli spheroplasts.
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Affiliation(s)
- Yibin Lin
- Division of Infectious Diseases, Department of Pediatrics, Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA.
| | - Lei Zheng
- Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA.,Department of Biochemistry and Biotechnology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation
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11
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Gislason AS, Turner K, Domaratzki M, Cardona ST. Comparative analysis of the Burkholderia cenocepacia K56-2 essential genome reveals cell envelope functions that are uniquely required for survival in species of the genus Burkholderia. Microb Genom 2019; 3. [PMID: 29208119 PMCID: PMC5729917 DOI: 10.1099/mgen.0.000140] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Burkholderia cenocepacia K56-2 belongs to the Burkholderia cepacia complex, a group of Gram-negative opportunistic pathogens that have large and dynamic genomes. In this work, we identified the essential genome of B. cenocepacia K56-2 using high-density transposon mutagenesis and insertion site sequencing (Tn-seq circle). We constructed a library of one million transposon mutants and identified the transposon insertions at an average of one insertion per 27 bp. The probability of gene essentiality was determined by comparing of the insertion density per gene with the variance of neutral datasets generated by Monte Carlo simulations. Five hundred and eight genes were not significantly disrupted, suggesting that these genes are essential for survival in rich, undefined medium. Comparison of the B. cenocepacia K56-2 essential genome with that of the closely related B. cenocepacia J2315 revealed partial overlapping, suggesting that some essential genes are strain-specific. Furthermore, 158 essential genes were conserved in B. cenocepacia and two species belonging to the Burkholderia pseudomallei complex, B. pseudomallei K96243 and Burkholderia thailandensis E264. Porins, including OpcC, a lysophospholipid transporter, LplT, and a protein involved in the modification of lipid A with aminoarabinose were found to be essential in Burkholderia genomes but not in other bacterial essential genomes identified so far. Our results highlight the existence of cell envelope processes that are uniquely essential in species of the genus Burkholderia for which the essential genomes have been identified by Tn-seq.
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Affiliation(s)
- April S Gislason
- 1Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Keith Turner
- 2Monsanto Company, 700 Chesterfield Parkway W, Chesterfield, MO, 63017, USA
| | - Mike Domaratzki
- 3Department of Computer Science, University of Manitoba, Winnipeg, R3T 2N2, Canada
| | - Silvia T Cardona
- 4Department of Medical Microbiology & Infectious Diseases, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada
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12
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Gupta D, Mohammed M, Mekala LP, Chintalapati S, Chintalapati VR. iTRAQ-based quantitative proteomics reveals insights into metabolic and molecular responses of glucose-grown cells of Rubrivivax benzoatilyticus JA2. J Proteomics 2018; 194:49-59. [PMID: 30597313 DOI: 10.1016/j.jprot.2018.12.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 12/19/2018] [Accepted: 12/26/2018] [Indexed: 01/28/2023]
Abstract
Anoxygenic photosynthetic bacteria thrive under diverse habitats utilising an extended range of inorganic/organic compounds under different growth modes. Although they display incredible metabolic flexibility, their responses and adaptations to changing carbon regimes is largely unexplored. In the present study, we employed iTRAQ-based global proteomic profiling and physiological studies to uncover the adaptive strategies of a phototrophic bacterium, Rubrivivax benzoatilyticus JA2 to glucose. Strain JA2 displayed altered growth rates, reduced cell size and progressive loss of pigmentation when grown on glucose compared to malate under photoheterotrophic condition. A ten-fold increase in the saturated to unsaturated fatty acid ratio of glucose-grown cells indicates a possible membrane adaptation. Proteomic profiling revealed extensive metabolic remodelling in the glucose-grown cells wherein signal-transduction, selective-transcription, DNA-repair, transport and protein quality control processes were up-regulated to cope with the changing milieu. Proteins involved in DNA replication, translation, electron-transport, photosynthetic machinery were down-regulated possibly to conserve the energy. Glycolysis/gluconeogenesis, TCA cycle and pigment biosynthesis were also down-regulated. The cell has activated alternative energy metabolic pathways viz., fatty acid β-oxidation, glyoxylate, acetate-switch and Entner-Doudoroff pathways. Overall, the present study deciphered the molecular/metabolic events associated with glucose-grown cells of strain JA2 and also unraveled how a carbon source modulates the metabolic phenotypes. SIGNIFICANCE: Anoxygenic photosynthetic bacteria (APB) exhibit incredible metabolic flexibility leading to diverse phenotypes. They thrive under diverse habitat using an array of inorganic/organic compounds as carbon sources, yet their metabolic adaptation to varying carbon regime is mostly unexplored. Present study uncovered the proteomic insights of the cellular responses of strain JA2 to changing carbon sources viz. malate and glucose under photoheterotrophic conditions. Our study suggests that carbon source can also determine the metabolic fate of the cells and reshape the energy dynamics of APB. Here, for the first time study highlighted the plausible carbon source (glucose) mediated regulation of photosynthesis in APB. The study sheds light on the plausible cellular events and adaptive metabolic strategies employed by strain JA2 in presence of non-preferred carbon source. It also revealed new insights into the metabolic plasticity of APB to the changing milieu.
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Affiliation(s)
- Deepshikha Gupta
- Department of Plant Sciences, P.O. Central University, University of Hyderabad, Hyderabad 500046, India
| | - Mujahid Mohammed
- Department of Plant Sciences, P.O. Central University, University of Hyderabad, Hyderabad 500046, India
| | - Lakshmi Prasuna Mekala
- Department of Plant Sciences, P.O. Central University, University of Hyderabad, Hyderabad 500046, India
| | - Sasikala Chintalapati
- Bacterial Discovery Laboratory, Centre for Environment, IST, JNT University Hyderabad, Kukatpally, Hyderabad 500085, India
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13
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Lin Y, Deepak RNVK, Zheng JZ, Fan H, Zheng L. A dual substrate-accessing mechanism of a major facilitator superfamily protein facilitates lysophospholipid flipping across the cell membrane. J Biol Chem 2018; 293:19919-19931. [PMID: 30373772 DOI: 10.1074/jbc.ra118.005548] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 10/23/2018] [Indexed: 11/06/2022] Open
Abstract
Lysophospholipid transporter (LplT) is a member of the major facilitator superfamily present in many Gram-negative bacteria. LplT catalyzes flipping of lysophospholipids (LPLs) across the bacterial inner membrane, playing an important role in bacterial membrane homeostasis. We previously reported that LplT promotes both uptake of exogenous LPLs and intramembranous LPL flipping across the bilayer. To gain mechanistic insight into this dual LPL-flipping activity, here we implemented a combination of computational approaches and LPL transport analyses to study LPL binding of and translocation by LplT. Our results suggest that LplT translocates LPLs through an elongated cavity exhibiting an extremely asymmetric polarity. We found that two D(E)N motifs form a head group-binding site, in which the carboxylate group of Asp-30 is important for LPL head group recognition. Substitutions of residues in the head group-binding site disrupted both LPL uptake and flipping activities. However, alteration of hydrophobic residues on the interface between the N- and C-terminal domains impaired LPL flipping specifically, resulting in LPLs accumulation in the membrane, but LPL uptake remained active. These results suggest a dual substrate-accessing mechanism, in which LplT recruits LPLs to its substrate-binding site via two routes, either from its extracellular entry or through a membrane-embedded groove between transmembrane helices, and then moves them toward the inner membrane leaflet. This LPL-flipping mechanism is likely conserved in many bacterial species, and our findings illustrate how LplT adjusts the major facilitator superfamily translocation pathway to perform its versatile lipid homeostatic functions.
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Affiliation(s)
- Yibin Lin
- From the Department of Biochemistry and Molecular Biology, Center for Membrane Biology, the University of Texas Health Science Center at Houston McGovern Medical School, Houston Texas 77030
| | - R N V Krishna Deepak
- the Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 138671 Singapore, and
| | - Jonathan Zixiang Zheng
- From the Department of Biochemistry and Molecular Biology, Center for Membrane Biology, the University of Texas Health Science Center at Houston McGovern Medical School, Houston Texas 77030
| | - Hao Fan
- the Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 138671 Singapore, and .,the Department of Biological Sciences (DBS), National University of Singapore, 117558 Singapore, and Center for Computational Biology, DUKE-NUS Medical School, 169857 Singapore
| | - Lei Zheng
- From the Department of Biochemistry and Molecular Biology, Center for Membrane Biology, the University of Texas Health Science Center at Houston McGovern Medical School, Houston Texas 77030,
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14
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Plasma lipidomic profile signature of rheumatoid arthritis versus Lyme arthritis patients. Arch Biochem Biophys 2018; 654:105-114. [PMID: 30059653 DOI: 10.1016/j.abb.2018.07.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/09/2018] [Accepted: 07/27/2018] [Indexed: 12/18/2022]
Abstract
OBJECTIVES Distinguishing of rheumatoid arthritis (RA) and Lyme arthritis (LA) is difficult, because of similar symptoms. This presents a significant clinical problem since treatments are quite different in both diseases. We investigated the plasma phospholipid profiles of RA and LA patients versus healthy subjects to find metabolic changes responsible for differentiation of both diseases. METHODS Plasma was collected from 9 RA, 9 LA, and 9 healthy subjects. Extracted lipids were analyzed using LC- MS/MS to characterize phospholipid profiles of RA, LA and healthy subjects. Principal components analysis (PCA), partial least squares-discriminate analysis (PLS-DA) and variable importance in projection (VIP) scores were used to estimate the importance of each phospholipid variable. RESULTS We identified 114 phospholipids in plasma. Phospholipid profiles were significantly different in RA and LA patients than in healthy subjects. Principal discriminant phospholipids between RA and LA groups were LPE (14:0), LPC(14:0) PI(18:0/20:4), PI(18:2/18:0), PI(16:1/18:2), PI(18:1/18:0), and PI(18:0/20:3). CONCLUSIONS Our study provides insights into the alteration of the plasma phospholipid profile of LA patients, resulting from Borrelia burgdorferi infection, that may lead to improved LA diagnosis and differentiation of this disease from RA. Furthermore, LPE (14:0) was found to have a high potential to be a possible biomarker of LA.
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15
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Abstract
The outer membrane (OM) bilayer of Gram-negative bacteria is biologically unique in its asymmetrical organization of lipids, with an inner leaflet composed of glycerophospholipids (PLs) and a surface-exposed outer leaflet composed of lipopolysaccharide (LPS). This lipid organization is integral to the OM’s barrier properties. Perturbations of the outer leaflet by antimicrobial peptides or defects in LPS biosynthesis or transport to the OM cause a compensatory flipping of PLs to the outer leaflet. As a result, lipid asymmetry is disrupted and OM integrity is compromised. Recently, we identified an Escherichia coli mutant that exhibits aberrant accumulation of surface PLs accompanied by a cellular increase in LPS production. Remarkably, the observed hyperproduction of LPS is PldA dependent. Here we provide evidence that the fatty acids generated by PldA at the OM are transported into the cytoplasm and simultaneously activated by thioesterification to coenzyme A (CoA) by FadD. The acyl-CoAs produced ultimately inhibit LpxC degradation by FtsH. The increased levels of LpxC, the enzyme that catalyzes the first committed step in LPS biosynthesis, increases the amount of LPS produced. Our data suggest that PldA acts as a sensor for lipid asymmetry in the OM. PldA protects the OM barrier by both degrading mislocalized PLs and generating lipid second messengers that enable long-distance signaling that prompts the cell to restore homeostasis at a distant organelle. The outer membrane of Gram-negative bacteria is an effective permeability barrier that protects the cell from toxic agents, including antibiotics. Barrier defects are often manifested by phospholipids present in the outer leaflet of this membrane that take up space normally occupied by lipopolysaccharide. We have discovered a signaling mechanism that operates across the entire cell envelope used by the cell to detect these outer membrane defects. A phospholipase, PldA, that functions to degrade these mislocalized phospholipids has a second, equally important function as a sensor. The fatty acids produced by hydrolysis of the phospholipids act as second messengers to signal the cell that more lipopolysaccharide is needed. These fatty acids diffuse across the periplasm and are transported into the cytoplasm by a process that attaches coenzyme A. The acyl-CoA molecule produces signals to inhibit the degradation of the critical enzyme LpxC by the ATP-dependent protease FtsH, increasing lipopolysaccharide production.
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16
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Lin Y, Bogdanov M, Lu S, Guan Z, Margolin W, Weiss J, Zheng L. The phospholipid-repair system LplT/Aas in Gram-negative bacteria protects the bacterial membrane envelope from host phospholipase A 2 attack. J Biol Chem 2018; 293:3386-3398. [PMID: 29348168 PMCID: PMC5836115 DOI: 10.1074/jbc.ra117.001231] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/15/2018] [Indexed: 11/06/2022] Open
Abstract
Secretory phospholipases A2 (sPLA2s) are potent components of mammalian innate-immunity antibacterial mechanisms. sPLA2 enzymes attack bacteria by hydrolyzing bacterial membrane phospholipids, causing membrane disorganization and cell lysis. However, most Gram-negative bacteria are naturally resistant to sPLA2 Here we report a novel resistance mechanism to mammalian sPLA2 in Escherichia coli, mediated by a phospholipid repair system consisting of the lysophospholipid transporter LplT and the acyltransferase Aas in the cytoplasmic membrane. Mutation of the lplT or aas gene abolished bacterial lysophospholipid acylation activity and drastically increased bacterial susceptibility to the combined actions of inflammatory fluid components and sPLA2, resulting in bulk phospholipid degradation and loss of colony-forming ability. sPLA2-mediated hydrolysis of the three major bacterial phospholipids exhibited distinctive kinetics and deacylation of cardiolipin to its monoacyl-derivative closely paralleled bacterial death. Characterization of the membrane envelope in lplT- or aas-knockout mutant bacteria revealed reduced membrane packing and disruption of lipid asymmetry with more phosphatidylethanolamine present in the outer leaflet of the outer membrane. Moreover, modest accumulation of lysophospholipids in these mutant bacteria destabilized the inner membrane and rendered outer membrane-depleted spheroplasts much more sensitive to sPLA2 These findings indicated that LplT/Aas inactivation perturbs both the outer and inner membranes by bypassing bacterial membrane maintenance mechanisms to trigger specific interfacial activation of sPLA2 We conclude that the LplT/Aas system is important for maintaining the integrity of the membrane envelope in Gram-negative bacteria. Our insights may help inform new therapeutic strategies to enhance host sPLA2 antimicrobial activity.
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Affiliation(s)
- Yibin Lin
- From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology and
| | | | - Shuo Lu
- From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology and
| | - Ziqiang Guan
- the Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, and
| | - William Margolin
- Microbiology and Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas 77030
| | - Jerrold Weiss
- the Inflammation Program and Departments of Internal Medicine and Microbiology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Lei Zheng
- From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology and
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17
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López-Lara IM, Geiger O. Bacterial lipid diversity. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1287-1299. [DOI: 10.1016/j.bbalip.2016.10.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 10/10/2016] [Accepted: 10/11/2016] [Indexed: 11/25/2022]
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18
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Zheng L, Lin Y, Lu S, Zhang J, Bogdanov M. Biogenesis, transport and remodeling of lysophospholipids in Gram-negative bacteria. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1404-1413. [PMID: 27956138 PMCID: PMC6162059 DOI: 10.1016/j.bbalip.2016.11.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 11/18/2022]
Abstract
Lysophospholipids (LPLs) are metabolic intermediates in bacterial phospholipid turnover. Distinct from their diacyl counterparts, these inverted cone-shaped molecules share physical characteristics of detergents, enabling modification of local membrane properties such as curvature. The functions of LPLs as cellular growth factors or potent lipid mediators have been extensively demonstrated in eukaryotic cells but are still undefined in bacteria. In the envelope of Gram-negative bacteria, LPLs are derived from multiple endogenous and exogenous sources. Although several flippases that move non-glycerophospholipids across the bacterial inner membrane were characterized, lysophospholipid transporter LplT appears to be the first example of a bacterial protein capable of facilitating rapid retrograde translocation of lyso forms of glycerophospholipids across the cytoplasmic membrane in Gram-negative bacteria. LplT transports lyso forms of the three bacterial membrane phospholipids with comparable efficiency, but excludes other lysolipid species. Once a LPL is flipped by LplT to the cytoplasmic side of the inner membrane, its diacyl form is effectively regenerated by the action of a peripheral enzyme, acyl-ACP synthetase/LPL acyltransferase (Aas). LplT-Aas also mediates a novel cardiolipin remodeling by converting its two lyso derivatives, diacyl or deacylated cardiolipin, to a triacyl form. This coupled remodeling system provides a unique bacterial membrane phospholipid repair mechanism. Strict selectivity of LplT for lyso lipids allows this system to fulfill efficient lipid repair in an environment containing mostly diacyl phospholipids. A rocker-switch model engaged by a pair of symmetric ion-locks may facilitate alternating substrate access to drive LPL flipping into bacterial cells. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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Affiliation(s)
- Lei Zheng
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston McGovern Medical School, 6431 Fannin Street, Houston, TX 77030, USA.
| | - Yibin Lin
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston McGovern Medical School, 6431 Fannin Street, Houston, TX 77030, USA
| | - Shuo Lu
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston McGovern Medical School, 6431 Fannin Street, Houston, TX 77030, USA
| | - Jiazhe Zhang
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston McGovern Medical School, 6431 Fannin Street, Houston, TX 77030, USA
| | - Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston McGovern Medical School, 6431 Fannin Street, Houston, TX 77030, USA
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19
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Lopalco P, Stahl J, Annese C, Averhoff B, Corcelli A. Identification of unique cardiolipin and monolysocardiolipin species in Acinetobacter baumannii. Sci Rep 2017; 7:2972. [PMID: 28592862 PMCID: PMC5462836 DOI: 10.1038/s41598-017-03214-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 04/20/2017] [Indexed: 01/05/2023] Open
Abstract
Acidic glycerophospholipids play an important role in determining the resistance of Gram-negative bacteria to stress conditions and antibiotics. Acinetobacter baumannii, an opportunistic human pathogen which is responsible for an increasing number of nosocomial infections, exhibits broad antibiotic resistances. Here lipids of A. baumannii have been analyzed by combined MALDI-TOF/MS and TLC analyses; in addition GC-MS analyses of fatty acid methyl esters released by methanolysis of membrane phospholipids have been performed. The main glycerophospholipids are phosphatidylethanolamine, phosphatidylglycerol, acyl-phosphatidylglycerol and cardiolipin together with monolysocardiolipin, a lysophospholipid only rarely detected in bacterial membranes. The major acyl chains in the phospholipids are C16:0 and C18:1, plus minor amounts of short chain fatty acids. The structures of the cardiolipin and monolysocardiolipin have been elucidated by post source decay mass spectrometry analysis. A large variety of cardiolipin and monolysocardiolipin species were found in A. baumannii. Similar lysocardiolipin levels were found in the two clinical strains A. baumannii ATCC19606T and AYE whereas in the nonpathogenic strain Acinetobacter baylyi ADP1 lysocardiolipin levels were highly reduced.
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Affiliation(s)
- Patrizia Lopalco
- Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Julia Stahl
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Cosimo Annese
- Italian National Council for Research - Institute for the Chemistry of OrganoMetallic Compounds (CNR-ICCOM), Bari, Italy
| | - Beate Averhoff
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Angela Corcelli
- Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy. .,Italian National Council for Research - Institute for Chemical-Physical Processes (CNR- IPCF), Bari, Italy.
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20
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May KL, Silhavy TJ. Making a membrane on the other side of the wall. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:1386-1393. [PMID: 27742351 DOI: 10.1016/j.bbalip.2016.10.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/20/2016] [Accepted: 10/04/2016] [Indexed: 12/11/2022]
Abstract
The outer membrane (OM) of Gram-negative bacteria is positioned at the frontline of the cell's interaction with its environment and provides a barrier against influx of external toxins while still allowing import of nutrients and excretion of wastes. It is a remarkable asymmetric bilayer with a glycolipid surface-exposed leaflet and a glycerophospholipid inner leaflet. Lipid asymmetry is key to OM barrier function and several different systems actively maintain this lipid asymmetry. All OM components are synthesized in the cytosol before being secreted and assembled into a contiguous membrane on the other side of the cell wall. Work in recent years has uncovered the pathways that transport and assemble most of the OM components. However, our understanding of how phospholipids are delivered to the OM remains notably limited. Here we will review seminal works in phospholipid transfer performed some 40years ago and place more recent insights in their context. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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Affiliation(s)
- Kerrie L May
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA.
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21
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Biosynthesis, remodeling and turnover of mitochondrial cardiolipin. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:3-7. [PMID: 27556952 DOI: 10.1016/j.bbalip.2016.08.010] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/03/2016] [Accepted: 08/17/2016] [Indexed: 12/15/2022]
Abstract
Among mitochondrial lipids, cardiolipin occupies a unique place. It is the only phospholipid that is specific to mitochondria and although it is merely a minor component, accounting for 10-20% of the total phospholipid content, cardiolipin plays an important role in the molecular organization, and thus the function of the cristae. This review covers the formation of cardiolipin, a phospholipid dimer containing two phosphatidyl residues, and its assembly into mitochondrial membranes. While a large body of literature exists on this topic, the review focuses on papers that appeared in the past three years. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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22
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Furse S, Scott DJ. Three-Dimensional Distribution of Phospholipids in Gram Negative Bacteria. Biochemistry 2016; 55:4742-7. [PMID: 27509296 DOI: 10.1021/acs.biochem.6b00541] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Exploration of the molecular structure of the bacterial cell envelope informs our understanding of its role in bacterial growth. This is crucial for research into both inhibiting and promoting bacterial growth as well as fundamental studies of cell cycle control. The spatial arrangement of the lipids in the cell envelope of Gram negative bacteria in particular has attracted considerable research attention in recent years. In this mini-review, we explore advances in understanding the spatial distribution of lipids in the model Gram negative prokaryote Escherichia coli. This includes the distribution of lipids in three dimensions, (a) lateral distribution within a monolayer, (b) asymmetry between bilayers and monolayers, and (c) distribution as a function of progress through membrane division (temporal shifts). We conclude that lipid distribution in E. coli and probably all bacteria is dynamic despite a narrow lipid profile and that the biophysical properties of the membrane are inhomogeneous as a result. Finally, we suggest that further work in this field may indicate how lipid distribution is controlled and what this means for bacterial growth and metabolism and even cell cycle control.
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Affiliation(s)
- Samuel Furse
- MBI, Department of Molecular Biology, University of Bergen , Thormøhlensgate 55, 5008 Bergen, Norway
| | - David J Scott
- National Centre for Macromolecular Hydrodynamics, University of Nottingham , College Road, Sutton Bonington, Nottinghamshire LE12 5RD, U.K.,ISIS Spallation Neutron Source, STFC, Rutherford Appleton Laboratory , Harwell Science and Innovation Campus, Harwell, Oxon OX11 0QX, U.K
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