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Si Z, Pethe K, Chan-Park MB. Chemical Basis of Combination Therapy to Combat Antibiotic Resistance. JACS AU 2023; 3:276-292. [PMID: 36873689 PMCID: PMC9975838 DOI: 10.1021/jacsau.2c00532] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 06/10/2023]
Abstract
The antimicrobial resistance crisis is a global health issue requiring discovery and development of novel therapeutics. However, conventional screening of natural products or synthetic chemical libraries is uncertain. Combination therapy using approved antibiotics with inhibitors targeting innate resistance mechanisms provides an alternative strategy to develop potent therapeutics. This review discusses the chemical structures of effective β-lactamase inhibitors, outer membrane permeabilizers, and efflux pump inhibitors that act as adjuvant molecules of classical antibiotics. Rational design of the chemical structures of adjuvants will provide methods to impart or restore efficacy to classical antibiotics for inherently antibiotic-resistant bacteria. As many bacteria have multiple resistance pathways, adjuvant molecules simultaneously targeting multiple pathways are promising approaches to combat multidrug-resistant bacterial infections.
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Affiliation(s)
- Zhangyong Si
- School
of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459
| | - Kevin Pethe
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921
- Singapore
Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551
| | - Mary B. Chan-Park
- School
of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921
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2
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Nazario LR, de Sousa JS, de Moraes Silveira FS, Costa KM, de Oliveira GMT, Bogo MR, da Silva RS. Participation of ecto-5'-nucleotidase in the inflammatory response in an adult zebrafish (Danio rerio) model. Comp Biochem Physiol C Toxicol Pharmacol 2022; 260:109402. [PMID: 35779837 DOI: 10.1016/j.cbpc.2022.109402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/20/2022] [Accepted: 06/26/2022] [Indexed: 11/17/2022]
Abstract
The ecto-5'-nucleotidase is an important source of adenosine in the extracellular medium. Adenosine modulation appears early in evolution and performs several biological functions, including a role as an anti-inflammatory molecule. Here, we evaluate the activity and mRNA expression of ecto-5'-nucleotidase in response to lipopolysaccharide (LPS) using zebrafish as a model. Adult zebrafish were injected with LPS (10 μg/g). White blood cell differential counts, inflammatory markers, and ecto-5'-nucleotidase activity and expression in the encephalon, kidney, heart, and intestine were evaluated at 2, 12, and 24 h post-injection (hpi). At 2 hpi of LPS, an increase in neutrophils and monocytes in peripheral blood was observed, which was accompanied by increased tnf-α expression in the heart, kidney, and encephalon, and increased cox-2 expression in the intestine and kidney. At 12 hpi, monocytes remained elevated in the peripheral blood, while tnf-α expression was also increased in the intestine. At 24 hpi, the white blood cell differential count no longer differed from that of the control, whereas tnf-α expression remained elevated in the encephalon but reduced in the kidney compared with the controls. AMP hydrolysis in LPS-treated animals was increased in the heart at 24 hpi [72 %; p = 0.029] without affecting ecto-5'-nucleotidase gene expression. These data indicate that, in most tissues studied, inflammation does not affect ecto-5'-nucleotidase activity, whereas in the heart, a delayed increase in ecto-5'-nucleotidase activity could be related to tissue repair.
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Affiliation(s)
- Luiza Reali Nazario
- Laboratório de Neuroquímica e Psicofarmacologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga, 6681, Caixa Postal 1429, 90619-900 Porto Alegre, RS, Brazil
| | - Jéssica Streb de Sousa
- Laboratório de Neuroquímica e Psicofarmacologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga, 6681, Caixa Postal 1429, 90619-900 Porto Alegre, RS, Brazil
| | - Francielle Schroeder de Moraes Silveira
- Laboratório de Neuroquímica e Psicofarmacologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga, 6681, Caixa Postal 1429, 90619-900 Porto Alegre, RS, Brazil
| | - Kesiane Mayra Costa
- Laboratório de Biologia Genômica e Molecular, Escola de Ciências da Saúde e Vida, PUCRS, Caixa Postal 1429, 90619-900 Porto Alegre, RS, Brazil
| | | | - Maurício Reis Bogo
- Laboratório de Biologia Genômica e Molecular, Escola de Ciências da Saúde e Vida, PUCRS, Caixa Postal 1429, 90619-900 Porto Alegre, RS, Brazil
| | - Rosane Souza da Silva
- Laboratório de Neuroquímica e Psicofarmacologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga, 6681, Caixa Postal 1429, 90619-900 Porto Alegre, RS, Brazil.
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3
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Yang H, Smith RD, Chandler CE, Johnson JK, Jackson SN, Woods AS, Scott AJ, Goodlett DR, Ernst RK. Lipid A Structural Determination from a Single Colony. Anal Chem 2022; 94:7460-7465. [PMID: 35576511 PMCID: PMC9392460 DOI: 10.1021/acs.analchem.1c05394] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We describe an innovative use for the recently reported fast lipid analysis technique (FLAT) that allows for the generation of MALDI tandem mass spectrometry data suitable for lipid A structure analysis directly from a single Gram-negative bacterial colony. We refer to this tandem MS version of FLAT as FLATn. Neither technique requires sophisticated sample preparation beyond the selection of a single bacterial colony, which significantly reduces overall analysis time (∼1 h), as compared to conventional methods. Moreover, the tandem mass spectra generated by FLATn provides comprehensive information on fragments of lipid A, for example, ester bonded acyl chain dissociations, cross-ring cleavages, and glycosidic bond dissociations, all of which allow the facile determination of novel lipid A structures or confirmation of expected structures. In addition to generating tandem mass spectra directly from single colonies, we also show that FLATn can be used to analyze lipid A structures taken directly from a complex biological clinical sample without the need for ex vivo growth. From a urine sample from a patient with an E. coli infection, FLATn identified the organism and demonstrated that this clinical isolate carried the mobile colistin resistance-1 gene (mcr-1) that results in the addition of a phosphoethanolamine moiety and subsequently resistance to the antimicrobial, colistin (polymyxin E). Moreover, FLATn allowed for the determination of the existence of a structural isomer in E. coli lipid A that had either a 1- or 4'-phosphate group modification by phosphoethanolamine generated by a change of bacterial culture conditions.
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Affiliation(s)
- Hyojik Yang
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
| | - Richard D. Smith
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
- Department of Pathology, School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Courtney E. Chandler
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
| | - J. Kristie Johnson
- Department of Pathology, School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Shelley N. Jackson
- Translational Analytical Core, NIDA IRP, NIH, Biomedical Research Center, 251 Bayview Boulevard, Suite 200, Room 01B216, Baltimore, MD 21224, USA
| | - Amina S. Woods
- Structural Biology Core, NIDA IRP, NIH, 333 Cassell Drive, Room 1120, Baltimore, MD 21224, USA
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine. Baltimore, MD 21205 USA
| | - Alison J. Scott
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
- Maastricht MultiModal Molecular Imaging (M4I) Institute, Maastricht University, Maastricht 6229 ER, Netherlands
| | - David R. Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road. Victoria, BC V8P 5C2, Canada
- International Centre for Cancer Vaccine Science, University of Gdańsk, ul. Kładki 24 80-822 Gdańsk, Poland
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201 USA
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Gerster T, Wröbel M, Hofstaedter CE, Schwudke D, Ernst RK, Ranf S, Gisch N. Remodeling of Lipid A in Pseudomonas syringae pv. phaseolicola In Vitro. Int J Mol Sci 2022; 23:1996. [PMID: 35216122 PMCID: PMC8876380 DOI: 10.3390/ijms23041996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 12/24/2022] Open
Abstract
Pseudomonas species infect a variety of organisms, including mammals and plants. Mammalian pathogens of the Pseudomonas family modify their lipid A during host entry to evade immune responses and to create an effective barrier against different environments, for example by removal of primary acyl chains, addition of phosphoethanolamine (P-EtN) to primary phosphates, and hydroxylation of secondary acyl chains. For Pseudomonas syringae pv. phaseolicola (Pph) 1448A, an economically important pathogen of beans, we observed similar lipid A modifications by mass spectrometric analysis. Therefore, we investigated predicted proteomes of various plant-associated Pseudomonas spp. for putative lipid A-modifying proteins using the well-studied mammalian pathogen Pseudomonas aeruginosa as a reference. We generated isogenic mutant strains of candidate genes and analyzed their lipid A. We show that the function of PagL, LpxO, and EptA is generally conserved in Pph 1448A. PagL-mediated de-acylation occurs at the distal glucosamine, whereas LpxO hydroxylates the secondary acyl chain on the distal glucosamine. The addition of P-EtN catalyzed by EptA occurs at both phosphates of lipid A. Our study characterizes lipid A modifications in vitro and provides a useful set of mutant strains relevant for further functional studies on lipid A modifications in Pph 1448A.
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Affiliation(s)
- Tim Gerster
- Chair of Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising-Weihenstephan, Germany;
| | - Michelle Wröbel
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany; (M.W.); (D.S.)
| | - Casey E. Hofstaedter
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (C.E.H.); (R.K.E.)
| | - Dominik Schwudke
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany; (M.W.); (D.S.)
- German Center for Infection Research (DZIF), Thematic Translational Unit Tuberculosis, Partner Site Hamburg-Lübeck-Borstel-Riems, 23845 Borstel, Germany
- Airway Research Center North, Member of the German Center for Lung Research (DZL), Site Research Center Borstel, 23845 Borstel, Germany
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (C.E.H.); (R.K.E.)
| | - Stefanie Ranf
- Chair of Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising-Weihenstephan, Germany;
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany; (M.W.); (D.S.)
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5
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Kwon Y, Park C, Lee J, Park DH, Jeong S, Yun CH, Park OJ, Han SH. Regulation of Bone Cell Differentiation and Activation by Microbe-Associated Molecular Patterns. Int J Mol Sci 2021; 22:ijms22115805. [PMID: 34071605 PMCID: PMC8197933 DOI: 10.3390/ijms22115805] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 02/06/2023] Open
Abstract
Gut microbiota has emerged as an important regulator of bone homeostasis. In particular, the modulation of innate immunity and bone homeostasis is mediated through the interaction between microbe-associated molecular patterns (MAMPs) and the host pattern recognition receptors including Toll-like receptors and nucleotide-binding oligomerization domains. Pathogenic bacteria such as Porphyromonas gingivalis and Staphylococcus aureus tend to induce bone destruction and cause various inflammatory bone diseases including periodontal diseases, osteomyelitis, and septic arthritis. On the other hand, probiotic bacteria such as Lactobacillus and Bifidobacterium species can prevent bone loss. In addition, bacterial metabolites and various secretory molecules such as short chain fatty acids and cyclic nucleotides can also affect bone homeostasis. This review focuses on the regulation of osteoclast and osteoblast by MAMPs including cell wall components and secretory microbial molecules under in vitro and in vivo conditions. MAMPs could be used as potential molecular targets for treating bone-related diseases such as osteoporosis and periodontal diseases.
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Affiliation(s)
- Yeongkag Kwon
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Korea; (Y.K.); (C.P.); (J.L.); (D.H.P.); (S.J.)
| | - Chaeyeon Park
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Korea; (Y.K.); (C.P.); (J.L.); (D.H.P.); (S.J.)
| | - Jueun Lee
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Korea; (Y.K.); (C.P.); (J.L.); (D.H.P.); (S.J.)
| | - Dong Hyun Park
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Korea; (Y.K.); (C.P.); (J.L.); (D.H.P.); (S.J.)
| | - Sungho Jeong
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Korea; (Y.K.); (C.P.); (J.L.); (D.H.P.); (S.J.)
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea;
| | - Ok-Jin Park
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Korea; (Y.K.); (C.P.); (J.L.); (D.H.P.); (S.J.)
- Correspondence: (O.-J.P.); (S.H.H.); Tel.: +82-2-880-2312 (O.-J.P.); +82-2-880-2310 (S.H.H.)
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, and Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Korea; (Y.K.); (C.P.); (J.L.); (D.H.P.); (S.J.)
- Correspondence: (O.-J.P.); (S.H.H.); Tel.: +82-2-880-2312 (O.-J.P.); +82-2-880-2310 (S.H.H.)
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6
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Anandan A, Vrielink A. Structure and function of lipid A-modifying enzymes. Ann N Y Acad Sci 2019; 1459:19-37. [PMID: 31553069 DOI: 10.1111/nyas.14244] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/26/2019] [Accepted: 09/05/2019] [Indexed: 12/30/2022]
Abstract
Lipopolysaccharides are complex molecules found in the cell envelop of many Gram-negative bacteria. The toxic activity of these molecules has led to the terminology of endotoxins. They provide bacteria with structural integrity and protection from external environmental conditions, and they interact with host signaling receptors to induce host immune responses. Bacteria have evolved enzymes that act to modify lipopolysaccharides, particularly the lipid A region of the molecule, to enable the circumvention of host immune system responses. These modifications include changes to lipopolysaccharide by the addition of positively charged sugars, such as N-Ara4N, and phosphoethanolamine (pEtN). Other modifications include hydroxylation, acylation, and deacylation of fatty acyl chains. We review the two-component regulatory mechanisms for enzymes that carry out these modifications and provide details of the structures of four enzymes (PagP, PagL, pEtN transferases, and ArnT) that modify the lipid A portion of lipopolysaccharides. We focus largely on the three-dimensional structures of these enzymes, which provide an understanding of how their substrate binding and catalytic activities are mediated. A structure-function-based understanding of these enzymes provides a platform for the development of novel therapeutics to treat antibiotic resistance.
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Affiliation(s)
- Anandhi Anandan
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Alice Vrielink
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia, Australia
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7
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Mishra VK, Buter J, Blevins MS, Witte MD, Van Rhijn I, Moody DB, Brodbelt JS, Minnaard AJ. Total Synthesis of an Immunogenic Trehalose Phospholipid from Salmonella Typhi and Elucidation of Its sn-Regiochemistry by Mass Spectrometry. Org Lett 2019; 21:5126-5131. [PMID: 31247773 PMCID: PMC6614791 DOI: 10.1021/acs.orglett.9b01725] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Diphosphatidyltrehalose (diPT) is an immunogenic glycolipid, recently isolated from Salmonella Typhi. Despite rigorous structure elucidation, the sn-position of the acyl chains on the glycerol backbone had not been unequivocally established. A stereoselective synthesis of diPT and its regioisomer is reported herein. Using a hybrid MS3 approach combining collisional dissociation and ultraviolet photodissociation mass spectrometry for analysis of the regioisomers and natural diPT, the regiochemistry of the acyl chains of this abundant immunostimulatory glycolipid was established.
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Affiliation(s)
- Vivek K Mishra
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - Jeffrey Buter
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - Molly S Blevins
- Department of Chemistry , University of Texas , Austin , Texas 78712 , United States
| | - Martin D Witte
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - Ildiko Van Rhijn
- Department of Infectious Diseases and Immunology, School of Veterinary Medicine , Utrecht University , 3584 CL Utrecht , The Netherlands.,Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital , Harvard Medical School , Boston , Massachusetts 02115 , United States
| | - D Branch Moody
- Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital , Harvard Medical School , Boston , Massachusetts 02115 , United States
| | - Jennifer S Brodbelt
- Department of Chemistry , University of Texas , Austin , Texas 78712 , United States
| | - Adriaan J Minnaard
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
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8
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Impact of CD14 on Reactive Oxygen Species Production from Human Leukocytes Primed by Escherichia coli Lipopolysaccharides. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6043245. [PMID: 30944694 PMCID: PMC6421816 DOI: 10.1155/2019/6043245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/11/2019] [Indexed: 12/14/2022]
Abstract
Lipopolysaccharides (LPS) from Gram-negative bacteria prime human polymorphonuclear neutrophils (PMNs) via multicomponent receptor cluster including CD14 and MD-2·TLR4 for the enhanced release of reactive oxygen species (ROS) were triggered by bacterial derived peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP). In this study, we investigated the impact of CD14 on LPS-induced priming of human PMNs for fMLP-triggered ROS generation (respiratory or oxidative) burst. Monoclonal antibodies against human CD14 (mAbs) as well as isotype-matched IgG2a did not influence significantly fMLP-triggered ROS production from LPS-unprimed PMNs. Anti-CD14 mAbs (clone UCHM-1) attenuated LPS-induced priming of PMNs as it had been mirrored by fMLP-triggered decrease of ROS production. Similar priming activity of S-LPS or Re-LPS from Escherichia coli for fMLP-triggered ROS release from PMNs was found. Obtained results suggest that glycosylphosphatidylinositol-anchored CD14 is the key player in LPS-induced PMN priming for fMLP-triggered ROS production. We believe that blockade of CD14 on the cell surface and clinical use of anti-CD14 mAbs or their Fab fragments may diminish the production of ROS and improve outcomes during cardiovascular diseases manifested by LPS-induced inflammation.
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9
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Kanie Y, Yamaguchi Y, Hayashi A, Uzawa J, Hatakeyama M, Hidaka Y, Toda N, Nakamura S, Kanie O. Structural analysis of a novel lipooligosaccharide (LOS) from Rhodobacter azotoformans. Carbohydr Res 2019; 473:104-114. [PMID: 30658251 DOI: 10.1016/j.carres.2018.12.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 12/30/2018] [Accepted: 12/30/2018] [Indexed: 01/26/2023]
Abstract
Lipopolysaccharides (LPS) are components of the Gram-negative bacterial cell surface that stimulate the host innate immune system through the Toll-like receptor (TLR) 4-MD-2 complex. Rhodobacter sp. have been reported to produce LPS that lack endotoxic activity, and instead act as antagonists of other endotoxins. In this report, we focused on LPS, especially the lipooligosaccharide (LOS) fraction produced by Rhodobacter azotoformans that shows production of IL-8, but has an inverse correlation with IL-6 production. We analyzed their molecular structure by using mass spectrometry and nuclear magnetic resonance spectroscopy and report a novel LOS consisting of a shorter glycan structure containing glucuronic acid but not heptoses. A novel glycan structure, Glcα(1 → 4)GlcAα(1 → 4)KDOα(2 → 4)[Glcα(1 → 5)]KDOα(2 → 6)[4-phosphate]GlcNβ(1 → 6) GlcNα1-phosphate, was proposed using NMR methods. The structure was consistent with one obtained based on MS. The MS analysis further revealed the existence of structural variation caused by extension with hexoses. The acyl composition in lipid A was suggested to contain three C14 fatty acyl chains (3-OH-14:0 or 3-oxo-14:0 at N2 of GlcN-1, 3-OH-14:0 at N2 of GlcN-2, that carried another 14:1 Δ7 on its β-hydroxyl group) and two C10 fatty acyl chains (3-OH-10:0 at O3 of both GlcN), which are same as those found in lipid A from Rhodobacter sphaeroides.
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Affiliation(s)
- Yoshimi Kanie
- Department of Applied Biochemistry, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa, 259-1292, Japan.
| | - Yoshiki Yamaguchi
- Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Akiyoshi Hayashi
- TFK Co., Ltd, 1-2-25-D407 Wadayamadori, Hyogo-ku, Kobe, Hyogo, 652-0884, Japan.
| | - Jun Uzawa
- Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Makoto Hatakeyama
- Nakamura Laboratory, RIKEN Baton Zone Program, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Yasuhiro Hidaka
- TFK Co., Ltd, 1-2-25-D407 Wadayamadori, Hyogo-ku, Kobe, Hyogo, 652-0884, Japan.
| | - Nobuhiro Toda
- TFK Co., Ltd, 1-2-25-D407 Wadayamadori, Hyogo-ku, Kobe, Hyogo, 652-0884, Japan.
| | - Shinichiro Nakamura
- Nakamura Laboratory, RIKEN Baton Zone Program, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Osamu Kanie
- Department of Applied Biochemistry, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa, 259-1292, Japan.
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10
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Evidence for substrate-assisted catalysis in N-acetylphosphoglucosamine mutase. Biochem J 2018; 475:2547-2557. [PMID: 29967067 PMCID: PMC6096347 DOI: 10.1042/bcj20180172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 07/02/2018] [Accepted: 07/02/2018] [Indexed: 11/17/2022]
Abstract
N-acetylphosphoglucosamine mutase (AGM1) is a key component of the hexosamine biosynthetic pathway that produces UDP-GlcNAc, an essential precursor for a wide range of glycans in eukaryotes. AGM belongs to the α-d-phosphohexomutase metalloenzyme superfamily and catalyzes the interconversion of N-acetylglucosamine-6-phosphate (GlcNAc-6P) to N-acetylglucosamine-1-phosphate (GlcNAc-1P) through N-acetylglucosamine-1,6-bisphosphate (GlcNAc-1,6-bisP) as the catalytic intermediate. Although there is an understanding of the phosphoserine-dependent catalytic mechanism at enzymatic and structural level, the identity of the requisite catalytic base in AGM1/phosphoglucomutases is as yet unknown. Here, we present crystal structures of a Michaelis complex of AGM1 with GlcNAc-6P and Mg2+, and a complex of the inactive Ser69Ala mutant together with glucose-1,6-bisphosphate (Glc-1,6-bisP) that represents key snapshots along the reaction co-ordinate. Together with mutagenesis, these structures reveal that the phosphate group of the hexose-1,6-bisP intermediate may act as the catalytic base.
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11
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Lima WG, Alves MC, Cruz WS, Paiva MC. Chromosomally encoded and plasmid-mediated polymyxins resistance in Acinetobacter baumannii: a huge public health threat. Eur J Clin Microbiol Infect Dis 2018. [PMID: 29524060 DOI: 10.1007/s10096-018-3223-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Acinetobacter baumannii is an opportunistic pathogen associated with nosocomial and community infections of great clinical relevance. Its ability to rapidly develop resistance to antimicrobials, especially carbapenems, has re-boosted the prescription and use of polymyxins. However, the emergence of strains resistant to these antimicrobials is becoming a critical issue in several regions of the world because very few of currently available antibiotics are effective in these cases. This review summarizes the most up-to-date knowledge about chromosomally encoded and plasmid-mediated polymyxins resistance in A. baumannii. Different mechanisms are employed by A. baumannii to overcome the antibacterial effects of polymyxins. Modification of the outer membrane through phosphoethanolamine addition, loss of lipopolysaccharide, symmetric rupture, metabolic changes affecting osmoprotective amino acids, and overexpression of efflux pumps are involved in this process. Several genetic elements modulate these mechanisms, but only three of them have been described so far in A. baumannii clinical isolates such as mutations in pmrCAB, lpxACD, and lpsB. Elucidation of genotypic profiles and resistance mechanisms are necessary for control and fight against resistance to polymyxins in A. baumannii, thereby protecting this class for future treatment.
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Affiliation(s)
- William Gustavo Lima
- Laboratory of Medical Microbiology, Central-West Campus Dona Lindu, Federal University of São João del-Rei, Rua Sebastião Gonçalves Coelho, 400, Divinopolis, Minas Gerais, 35501-293, Brazil.
| | - Mara Cristina Alves
- Laboratory of Laboratorial Diagnostic and Clinical Microbiology, Central-West Campus Dona Lindu, Federal University of São João del-Rei, Divinopolis, MG, Brazil
| | - Waleska Stephanie Cruz
- Laboratory of Molecular and Celular Biology, Alto Paraopeba Campus, Federal University of São João del-Rei, Ouro Branco, MG, Brazil
| | - Magna Cristina Paiva
- Laboratory of Laboratorial Diagnostic and Clinical Microbiology, Central-West Campus Dona Lindu, Federal University of São João del-Rei, Divinopolis, MG, Brazil
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Abstract
LPS is a potent bacterial endotoxin that triggers the innate immune system. Proper recognition of LPS by pattern-recognition receptors requires a full complement of typically six acyl chains in the lipid portion. Acyloxyacyl hydrolase (AOAH) is a host enzyme that removes secondary (acyloxyacyl-linked) fatty acids from LPS, rendering it immunologically inert. This activity is critical for recovery from immune tolerance that follows Gram-negative infection. To understand the molecular mechanism of AOAH function, we determined its crystal structure and its complex with LPS. The substrate's lipid moiety is accommodated in a large hydrophobic pocket formed by the saposin and catalytic domains with a secondary acyl chain inserted into a narrow lateral hydrophobic tunnel at the active site. The enzyme establishes dispensable contacts with the phosphate groups of LPS but does not interact with its oligosaccharide portion. Proteolytic processing allows movement of an amphipathic helix possibly involved in substrate access at membranes.
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13
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Deng C, Li X, Xue X, Pashley RM. The effects of low levels of trivalent ions on a standard strain of Escherichia coli (ATCC 11775) in aqueous solutions. Microbiologyopen 2018; 7:e00574. [PMID: 29334190 PMCID: PMC6011944 DOI: 10.1002/mbo3.574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/16/2017] [Accepted: 11/20/2017] [Indexed: 12/13/2022] Open
Abstract
Considering the ever‐growing usage of trivalent salts in water treatment, for example, lanthanum salts in rare earth, AlCl3 and FeCl3, the effects of different trivalent cations on the bacterium Escherichia coli (E. coli) ATCC 11775 strain have been studied in aqueous solutions. From colony incubation studies, the colony‐forming unit (CFU) densities were found to decrease significantly in the presence of even low levels (10−5 mol/L) of lanthanum chloride. This level of reduction in CFU number is comparable to the results obtained using the known bacteriocidal cationic surfactant, C14TAB. By comparison, exposure of the cells to low levels of trivalent ion, aluminum and chromium ion solutions produced only modest reductions in CFU density. The results from the incubation studies suggest that the bacteriostatic mechanism of La3+ ions has similarities to that of the cationic surfactant, and different to that of the other trivalent ions. Size distribution and zeta potential measurements of E. coli cells and phospholipid vesicles in the presence of trivalent cations solutions suggested significant cell shrinkage probably caused by membrane disruption.
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Affiliation(s)
- Can Deng
- POWERCHINA Water Environment Governance, Shenzhen, China
| | - Xinpeng Li
- POWERCHINA Water Environment Governance, Shenzhen, China
| | - Xinkai Xue
- POWERCHINA Water Environment Governance, Shenzhen, China
| | - Richard M Pashley
- School of Physical, Environmental & Mathematical Sciences, Canberra, Australia
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14
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Nicosia A, Bennici C, Biondo G, Costa S, Di Natale M, Masullo T, Monastero C, Ragusa MA, Tagliavia M, Cuttitta A. Characterization of Translationally Controlled Tumour Protein from the Sea Anemone Anemonia viridis and Transcriptome Wide Identification of Cnidarian Homologues. Genes (Basel) 2018; 9:genes9010030. [PMID: 29324689 PMCID: PMC5793182 DOI: 10.3390/genes9010030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/05/2018] [Accepted: 01/05/2018] [Indexed: 02/06/2023] Open
Abstract
Gene family encoding translationally controlled tumour protein (TCTP) is defined as highly conserved among organisms; however, there is limited knowledge of non-bilateria. In this study, the first TCTP homologue from anthozoan was characterised in the Mediterranean Sea anemone, Anemonia viridis. The release of the genome sequence of Acropora digitifera, Exaiptasia pallida, Nematostella vectensis and Hydra vulgaris enabled a comprehensive study of the molecular evolution of TCTP family among cnidarians. A comparison among TCTP members from Cnidaria and Bilateria showed conserved intron exon organization, evolutionary conserved TCTP signatures and 3D protein structure. The pattern of mRNA expression profile was also defined in A. viridis. These analyses revealed a constitutive mRNA expression especially in tissues with active proliferation. Additionally, the transcriptional profile of A. viridis TCTP (AvTCTP) after challenges with different abiotic/biotic stresses showed induction by extreme temperatures, heavy metals exposure and immune stimulation. These results suggest the involvement of AvTCTP in the sea anemone defensome taking part in environmental stress and immune responses.
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Affiliation(s)
- Aldo Nicosia
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
| | - Carmelo Bennici
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
| | - Girolama Biondo
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
| | - Salvatore Costa
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Viale delle Scienze, Ed. 16, 90128 Palermo, Sicily, Italy.
| | - Marilena Di Natale
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
| | - Tiziana Masullo
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
| | - Calogera Monastero
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
| | - Maria Antonietta Ragusa
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Viale delle Scienze, Ed. 16, 90128 Palermo, Sicily, Italy.
| | - Marcello Tagliavia
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
| | - Angela Cuttitta
- National Research Council-Institute for Marine and Coastal Environment (IAMC-CNR), Laboratory of Molecular Ecology and Biotechnology, Detached Unit of Capo Granitola, Via del mare, 91021 Torretta Granitola (TP), Sicily, Italy.
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15
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Keppen OI, Ivanovsky RN, Streshinskaya GM, Lebedeva NV, Shashkov AS, Dmitrenok AS, Grouzdev DS. The cell wall of the filamentous anoxygenic phototrophic bacterium Oscillochloris trichoides. Microbiology (Reading) 2018; 164:57-64. [DOI: 10.1099/mic.0.000590] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Olga I. Keppen
- Faculty of Biology, Lomonosov Moscow State University, 119991, Leninskie Gory 1-12, Moscow, Russia
| | - Ruslan N. Ivanovsky
- Faculty of Biology, Lomonosov Moscow State University, 119991, Leninskie Gory 1-12, Moscow, Russia
| | - Galina M. Streshinskaya
- Faculty of Biology, Lomonosov Moscow State University, 119991, Leninskie Gory 1-12, Moscow, Russia
| | - Natalia V. Lebedeva
- Faculty of Biology, Lomonosov Moscow State University, 119991, Leninskie Gory 1-12, Moscow, Russia
| | - Alexander S. Shashkov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky Ave., 47, Moscow, Russia
| | - Andrey S. Dmitrenok
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky Ave., 47, Moscow, Russia
| | - Denis S. Grouzdev
- Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Leninsky Ave. 33, bld. 2, Moscow, Russia
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16
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Crittenden CM, Akin LD, Morrison LJ, Trent MS, Brodbelt JS. Characterization of Lipid A Variants by Energy-Resolved Mass Spectrometry: Impact of Acyl Chains. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1118-1126. [PMID: 27966172 PMCID: PMC5438766 DOI: 10.1007/s13361-016-1542-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/19/2016] [Accepted: 10/24/2016] [Indexed: 05/04/2023]
Abstract
Lipid A molecules consist of a diglucosamine sugar core with a number of appended acyl chains that vary in their length and connectivity. Because of the challenging nature of characterizing these molecules and differentiating between isomeric species, an energy-resolved MS/MS strategy was undertaken to track the fragmentation trends and map genealogies of product ions originating from consecutive cleavages of acyl chains. Generalizations were developed based on the number and locations of the primary and secondary acyl chains as well as variations in preferential cleavages arising from the location of the phosphate groups. Secondary acyl chain cleavage occurs most readily for lipid A species at the 3' position, followed by primary acyl chain fragmentation at both the 3' and 3 positions. In the instances of bisphosphorylated lipid A variants, phosphate loss occurs readily in conjunction with the most favorable primary and secondary acyl chain cleavages. Graphical Abstract ᅟ.
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Affiliation(s)
| | - Lucas D Akin
- Department of Chemistry, University of Texas, Austin, TX, 78712, USA
| | | | - M Stephen Trent
- Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA
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17
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Obeng EM, Dullah EC, Razak NSA, Danquah MK, Budiman C, Ongkudon CM. Elucidating endotoxin-biomolecule interactions with FRET: extending the frontiers of their supramolecular complexation. J Biol Methods 2017; 4:e71. [PMID: 31453229 PMCID: PMC6706125 DOI: 10.14440/jbm.2017.172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/24/2017] [Accepted: 02/28/2017] [Indexed: 01/22/2023] Open
Abstract
Endotoxin has been one of the topical chemical contaminants of major concern to researchers, especially in the field of bioprocessing. This major concern of researchers stems from the fact that the presence of Gram-negative bacterial endotoxin in intracellular products is unavoidable and requires complex downstream purification steps. For instance, endotoxin interacts with recombinant proteins, peptides, antibodies and aptamers and these interactions have formed the foundation for most biosensors for endotoxin detection. It has become imperative for researchers to engineer reliable means/techniques to detect, separate and remove endotoxin, without compromising the quality and quantity of the end-product. However, the underlying mechanism involved during endotoxin-biomolecule interaction is still a gray area. The use of quantitative molecular microscopy that provides high resolution of biomolecules is highly promising, hence, may lead to the development of improved endotoxin detection strategies in biomolecule preparation. Förster resonance energy transfer (FRET) spectroscopy is one of the emerging most powerful tools compatible with most super-resolution techniques for the analysis of molecular interactions. However, the scope of FRET has not been well-exploited in the analysis of endotoxin-biomolecule interaction. This article reviews endotoxin, its pathophysiological consequences and the interaction with biomolecules. Herein, we outline the common potential ways of using FRET to extend the current understanding of endotoxin-biomolecule interaction with the inference that a detailed understanding of the interaction is a prerequisite for the design of strategies for endotoxin identification and removal from protein milieus.
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Affiliation(s)
- Eugene M Obeng
- Biotechnology Research Institute, University Malaysia Sabah, Kota Kinabalu, Sabah 88400, Malaysia
| | - Elvina C Dullah
- Biotechnology Research Institute, University Malaysia Sabah, Kota Kinabalu, Sabah 88400, Malaysia
| | | | - Michael K Danquah
- Department of Chemical Engineering, Curtin University Sarawak, Miri, Sarawak 98009, Malaysia
| | - Cahyo Budiman
- Biotechnology Research Institute, University Malaysia Sabah, Kota Kinabalu, Sabah 88400, Malaysia
| | - Clarence M Ongkudon
- Biotechnology Research Institute, University Malaysia Sabah, Kota Kinabalu, Sabah 88400, Malaysia
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18
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Polyspecificity of Anti-lipid A Antibodies and Its Relevance to the Development of Autoimmunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 966:181-202. [PMID: 28887790 DOI: 10.1007/5584_2017_94] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The process of natural selection favours germ-line gene segments that encode CDRs that have the ability to recognize a range of structurally related antigens. This presents an immunological advantage to the host, as it can confer protection against a common pathogen and still cope with new or changing antigens. Cross-reactive and polyspecific antibodies also play a central role in autoimmune responses, and a link has been shown to exist between auto-reactive B cells and certain bacterial infections. Bacterial DNA, lipids, and carbohydrates have been implicated in the progression of autoimmune diseases such as systemic lupus erythematosus. As well, reports of anti-lipid A antibody polyspecificity towards single-stranded DNA together with the observed sequence homology amongst isolated auto- and anti-lipid A antibodies has prompted further study of this phenomenon. Though the lipid A epitope appears cryptic during Gram-negative bacterial infection, there have been several reported instances of lipid A-specific antibodies isolated from human sera, some of which have exhibited polyspecificity for single stranded DNA. In such cases, the breakdown of negative selection through polyspecificity can have the unfortunate consequence of autoimmune disease. This review summarizes current knowledge regarding such antibodies and emphasizes the features of S1-15, A6, and S55-5, anti-lipid A antibodies whose structures were recently determined by X-ray crystallography.
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19
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Kucharska I, Liang B, Ursini N, Tamm LK. Molecular Interactions of Lipopolysaccharide with an Outer Membrane Protein from Pseudomonas aeruginosa Probed by Solution NMR. Biochemistry 2016; 55:5061-72. [PMID: 27532487 DOI: 10.1021/acs.biochem.6b00630] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen causing pneumonias that are particularly severe in cystic fibrosis and immunocompromised patients. The outer membrane (OM) of P. aeruginosa is much less permeable to nutrients and other chemical compounds than that of Escherichia coli. The low permeability of the OM, which also contributes to Pseudomonas' significant antibiotic resistance, is augmented by the presence of the outer membrane protein H (OprH). OprH directly interacts with lipopolysaccharides (LPS) that constitute the outer leaflet of the OM and thus contributes to the structural stability of the OM. In this study, we used solution NMR spectroscopy to characterize the interactions between LPS and OprH in molecular detail. NMR chemical shift perturbations observed upon the addition of LPS to OprH in DHPC micelles indicate that this interaction is predominantly electrostatic and localized to the extracellular loops 2 and 3 and a number of highly conserved basic residues near the extracellular barrel rim of OprH. Single-site mutations of these residues were not enough to completely abolish binding, but OprH with cumulative mutations of Lys70, Arg72, and Lys103 no longer binds LPS. The dissociation constant (∼200 μM) measured by NMR is sufficient to efficiently bind LPS to OprH in the OM. This work highlights that solution NMR is suitable to study specific interactions of lipids with integral membrane proteins and provides a detailed molecular model for the interaction of LPS with OprH; i.e., an interaction that contributes to the integrity of the OM of P. aeruginosa under low divalent cation and antibiotic stress conditions. These methods should thus be useful for screening antibiotics that might disrupt OprH-LPS interactions and thereby increase the permeability of the OM of P. aeruginosa.
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Affiliation(s)
- Iga Kucharska
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine , Charlottesville, Virginia 22908, United States
| | - Binyong Liang
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine , Charlottesville, Virginia 22908, United States
| | - Nicholas Ursini
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine , Charlottesville, Virginia 22908, United States
| | - Lukas K Tamm
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine , Charlottesville, Virginia 22908, United States
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20
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Hashimoto M, Ozono M, Furuyashiki M, Baba R, Hashiguchi S, Suda Y, Fukase K, Fujimoto Y. Characterization of a Novel d-Glycero-d-talo-oct-2-ulosonic acid-substituted Lipid A Moiety in the Lipopolysaccharide Produced by the Acetic Acid Bacterium Acetobacter pasteurianus NBRC 3283. J Biol Chem 2016; 291:21184-21194. [PMID: 27539854 DOI: 10.1074/jbc.m116.751271] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Indexed: 01/17/2023] Open
Abstract
Acetobacter pasteurianus is an aerobic Gram-negative rod that is used in the fermentation process used to produce the traditional Japanese black rice vinegar kurozu. Previously, we found that a hydrophobic fraction derived from kurozu stimulates Toll-like receptors to produce cytokines. LPSs, particularly LPS from A. pasteurianus, are strong candidates for the immunostimulatory component of kurozu. The LPS of A. pasteurianus remains stable in acidic conditions during the 2 years of the abovementioned fermentation process. Thus, we hypothesized that its stability results from its structure. In this study, we isolated the LPS produced by A. pasteurianus NBRC 3283 bacterial cells and characterized the structure of its lipid A component. The lipid A moiety was obtained by standard weak acid hydrolysis of the LPS. However, the hydrolysis was incomplete because a certain proportion of the LPS contained acid-stable d-glycero-d-talo-oct-2-ulosonic acid (Ko) residues instead of the acid-labile 3-deoxy-d-manno-oct-2-ulosonic acid residues that are normally found in typical LPS. Even so, we obtained a Ko-substituted lipid A with a novel sugar backbone, α-Man(1-4)[α-Ko(2-6)]β-GlcN3N(1-6)α-GlcN(1-1)α-GlcA. Its reducing end GlcN(1-1)GlcA bond was also found to be quite acid-stable. Six fatty acids were attached to the backbone. Both the whole LPS and the lipid A moiety induced TNF-α production in murine cells via Toll-like receptor 4, although their activity was weaker than those of Escherichia coli LPS and lipid A. These results suggest that the structurally atypical A. pasteurianus lipid A found in this study remains stable and, hence, retains its immunostimulatory activity during acetic acid fermentation.
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Affiliation(s)
- Masahito Hashimoto
- From the Department of Chemistry, Biotechnology, and Chemical Engineering, Kagoshima University, Kagoshima 890-0065, Japan,
| | - Mami Ozono
- From the Department of Chemistry, Biotechnology, and Chemical Engineering, Kagoshima University, Kagoshima 890-0065, Japan
| | - Maiko Furuyashiki
- From the Department of Chemistry, Biotechnology, and Chemical Engineering, Kagoshima University, Kagoshima 890-0065, Japan
| | - Risako Baba
- From the Department of Chemistry, Biotechnology, and Chemical Engineering, Kagoshima University, Kagoshima 890-0065, Japan
| | - Shuhei Hashiguchi
- From the Department of Chemistry, Biotechnology, and Chemical Engineering, Kagoshima University, Kagoshima 890-0065, Japan
| | - Yasuo Suda
- From the Department of Chemistry, Biotechnology, and Chemical Engineering, Kagoshima University, Kagoshima 890-0065, Japan
| | - Koichi Fukase
- the Department of Chemistry, Graduate School of Science, Osaka University, Osaka 560-0043, Japan, and
| | - Yukari Fujimoto
- the Faculty of Science and Technology, Keio University, Kanagawa 223-8522, Japan
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21
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Vinnitskiy DZ, Ustyuzhanina NE, Nifantiev NE. Natural bacterial and plant biomolecules bearing α-d-glucuronic acid residues. Russ Chem Bull 2016. [DOI: 10.1007/s11172-015-1010-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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22
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Mahat R, Seebart C, Basile F, Ward NL. Global and Targeted Lipid Analysis of Gemmata obscuriglobus Reveals the Presence of Lipopolysaccharide, a Signature of the Classical Gram-Negative Outer Membrane. J Bacteriol 2016; 198:221-36. [PMID: 26483522 PMCID: PMC4751799 DOI: 10.1128/jb.00517-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/10/2015] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Planctomycete bacteria possess many unusual cellular properties, contributing to a cell plan long considered to be unique among the bacteria. However, data from recent studies are more consistent with a modified Gram-negative cell plan. A key feature of the Gram-negative plan is the presence of an outer membrane (OM), for which lipopolysaccharide (LPS) is a signature molecule. Despite genomic evidence for an OM in planctomycetes, no biochemical verification has been reported. We attempted to detect and characterize LPS in the planctomycete Gemmata obscuriglobus. We obtained direct evidence for LPS and lipid A using electrophoresis and differential staining. Gas chromatography-mass spectrometry (GC-MS) compositional analysis of LPS extracts identified eight different 3-hydroxy fatty acids (3-HOFAs), 2-keto 3-deoxy-d-manno-octulosonic acid (Kdo), glucosamine, and hexose and heptose sugars, a chemical profile unique to Gram-negative LPS. Combined with molecular/structural information collected from matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS analysis of putative intact lipid A, these data led us to propose a heterogeneous hexa-acylated lipid A structure (multiple-lipid A species). We also confirmed previous reports of G. obscuriglobus whole-cell fatty acid (FA) and sterol compositions and detected a novel polyunsaturated FA (PUFA). Our confirmation of LPS, and by implication an OM, in G. obscuriglobus raises the possibility that other planctomycetes possess an OM. The pursuit of this question, together with studies of the structural connections between planctomycete LPS and peptidoglycans, will shed more light on what appears to be a planctomycete variation on the Gram-negative cell plan. IMPORTANCE Bacterial species are classified as Gram positive or negative based on their cell envelope structure. For 25 years, the envelope of planctomycete bacteria has been considered a unique exception, as it lacks peptidoglycan and an outer membrane (OM). However, the very recent detection of peptidoglycan in planctomycete species has provided evidence for a more conventional cell wall and raised questions about other elements of the cell envelope. Here, we report direct evidence of lipopolysaccharide in the planctomycete G. obscuriglobus, suggesting the presence of an OM and supporting the proposal that the planctomycete cell envelope is an extension of the canonical Gram-negative plan. This interpretation features a convoluted cytoplasmic membrane and expanded periplasmic space, the functions of which provide an intriguing avenue for future investigation.
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Affiliation(s)
- Rajendra Mahat
- Department of Chemistry, University of Wyoming, Laramie, Wyoming, USA
| | - Corrine Seebart
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, USA
| | - Franco Basile
- Department of Chemistry, University of Wyoming, Laramie, Wyoming, USA
| | - Naomi L Ward
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, USA
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23
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Montoya CA, Rutherfurd SM, Moughan PJ. Nondietary Gut Materials Interfere with the Determination of Dietary Fiber Digestibility in Growing Pigs When Using the Prosky Method. J Nutr 2015; 145:1966-72. [PMID: 26063063 DOI: 10.3945/jn.115.212639] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/14/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Reported negative ileal and total tract dietary fiber (DF) digestibility values are physiologically untenable and suggest the presence of nondietary material in the gut contents that interferes with the DF determination. OBJECTIVE The objective of this study was to demonstrate the importance of interfering material (IM) when the Prosky method was used to determine DF digestibility. METHODS Fourteen pigs (41.6 ± 3.0 kg) were surgically implanted with ileal T-cannulas. A semisynthetic fiber-free diet and 2 semisynthetic diets containing kiwifruit as the sole fiber source [25 or 50 g fiber/kg dry matter (DM)] were prepared. Titanium dioxide was used as an indigestible marker. Pigs were fed the kiwifruit-containing diets (n=7 per diet) for 44 d, followed by the fiber-free diet (n=14) for 7 d. Ileal digesta and feces were collected over 3 d, starting on days 42 and 49. The flow of IM and the soluble, insoluble, and total DF digestibility were determined. RESULTS Considerable amounts of IM were present when the Prosky method was applied to ileal digesta (12 g/kg DM intake) and feces (28 g/kg DM intake) collected from pigs fed the fiber-free diet after adaptation to the diet containing 50 g/kg DM of fiber. The pigs adapted to the highest fiber concentration had 0.9- and 0.7-fold greater ileal and fecal IM flows than their counterparts adapted to the lowest concentration. In the ileal digesta, crude mucin was the main IM source in the soluble DF fraction (66%). In the ileal digesta and feces, microbial cells were the main IM source in the insoluble DF fraction. The determined ileal soluble DF and total tract insoluble DF digestibilities increased by 44-54% and 78% respectively after correction for IM (P < 0.001). CONCLUSIONS Large amounts of IM are present in ileal digesta and feces of pigs when fiber is determined with the Prosky method, leading to a marked underestimation.
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Affiliation(s)
- Carlos A Montoya
- Riddet Institute, Massey University, Palmerston North, New Zealand
| | | | - Paul J Moughan
- Riddet Institute, Massey University, Palmerston North, New Zealand
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Porphyromonas gingivalis Periodontal Infection and Its Putative Links with Alzheimer's Disease. Mediators Inflamm 2015; 2015:137357. [PMID: 26063967 PMCID: PMC4430664 DOI: 10.1155/2015/137357] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/01/2015] [Indexed: 12/18/2022] Open
Abstract
Periodontal disease (PD) and Alzheimer's disease (AD) are inflammatory conditions affecting the global adult population. In the pathogenesis of PD, subgingival complex bacterial biofilm induces inflammation that leads to connective tissue degradation and alveolar bone resorption around the teeth. In health, junctional epithelium seals the gingiva to the tooth enamel, thus preventing bacteria from entering the gingivae. Chronic PD involves major pathogens (Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) which have an immune armoury that can circumvent host's immune surveillance to create and maintain an inflammatory mediator rich and toxic environment to grow and survive. The neurodegenerative condition, AD, is characterised by poor memory and specific hallmark proteins; periodontal pathogens are increasingly being linked with this dementing condition. It is therefore becoming important to understand associations of periodontitis with relevance to late-onset AD. The aim of this review is to discuss the relevance of finding the keystone periodontal pathogen P. gingivalis in AD brains and its plausible contribution to the aetiological hypothesis of this dementing condition.
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Arihara R, Kakita K, Yamada K, Nakamura S, Hashimoto S. Synthesis of the Tetrasaccharide Repeating Unit from Acinetobacter baumannii Serogroup O18 Capitalizing on Phosphorus-Containing Leaving Groups. J Org Chem 2015; 80:4278-88. [DOI: 10.1021/acs.joc.5b00139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ryoichi Arihara
- Faculty of Pharmaceutical
Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Kosuke Kakita
- Faculty of Pharmaceutical
Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Kazuhiro Yamada
- Faculty of Pharmaceutical
Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Seiichi Nakamura
- Faculty of Pharmaceutical
Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Shunichi Hashimoto
- Faculty of Pharmaceutical
Sciences, Hokkaido University, Sapporo 060-0812, Japan
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Β-hydroxymyristic acid as a chemical marker to detect endotoxins in dialysis water. Anal Biochem 2014; 470:71-7. [PMID: 25449302 DOI: 10.1016/j.ab.2014.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/19/2014] [Accepted: 10/21/2014] [Indexed: 11/22/2022]
Abstract
An analytical chemical method has been developed for determination of β-hydroxymyristic acid (β-HMA), a component of lipopolysaccharides (LPSs/endotoxins) in dialysis water. In our investigation, the β-HMA component was used as a chemical marker for endotoxin presence in dialysis water because it is available in the molecular subunit (lipid A) and responsible for toxicity. It is the most abundant saturated fatty acid in that subunit. The developed method is based on fluorescence derivatization with 4-nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ). A high-performance liquid chromatographic separation of the β-HMA derivative was achieved using an octadecyl silica column in gradient elution. A wide dynamic range of β-HMA was tested and a calibration curve was constructed with accuracy of 90% and variability of less than 10%. The limits of detection and quantification obtained were 2 and 5μM, respectively. The developed method was applied to detect endotoxins in dialysis water by alkaline hydrolysis of LPS using NaOH (0.25M) at 60°C for 2h. After hydrolysis, free acid was detected as its NBD-PZ derivative using high-performance liquid chromatography/mass spectrometry (HPLC/MS). Good recovery rates ranging from 98 to 105% were obtained for β-HMA in dialysis water.
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Varbanets LD. Glycopolymers of microorganisms: Achievements and future research (review). APPL BIOCHEM MICRO+ 2014. [DOI: 10.1134/s0003683814060143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Chiominto A, Marcelloni AM, Tranfo G, Paba E, Paci E. Validation of a high performance liquid chromatography-tandem mass spectrometry method for β-hydroxy fatty acids as environmental markers of lipopolysaccharide. J Chromatogr A 2014; 1353:65-70. [DOI: 10.1016/j.chroma.2014.01.052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 01/15/2014] [Accepted: 01/17/2014] [Indexed: 11/24/2022]
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Screening of a Leptospira biflexa mutant library to identify genes involved in ethidium bromide tolerance. Appl Environ Microbiol 2014; 80:6091-103. [PMID: 25063661 DOI: 10.1128/aem.01619-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Leptospira spp. are spirochete bacteria comprising both pathogenic and free-living species. The saprophyte L. biflexa is a model bacterium for studying leptospiral biology due to relative ease of culturing and genetic manipulation. In this study, we constructed a library of 4,996 random transposon mutants in L. biflexa. We screened the library for increased susceptibility to the DNA intercalating agent, ethidium bromide (EtBr), in order to identify genetic determinants that reduce L. biflexa susceptibility to antimicrobial agents. By phenotypic screening, using subinhibitory EtBr concentrations, we identified 29 genes that, when disrupted via transposon insertion, led to increased sensitivity of the bacteria to EtBr. At the functional level, these genes could be categorized by function as follows: regulation and signaling (n=11), transport (n=6), membrane structure (n=5), stress response (n=2), DNA damage repair (n=1), and other processes (n=3), while 1 gene had no predicted function. Genes involved in transport (including efflux pumps) and regulation (two-component systems, anti-sigma factor antagonists, etc.) were overrepresented, demonstrating that these genes are major contributors to EtBr tolerance. This finding suggests that transport genes which would prevent EtBr to enter the cell cytoplasm are critical for EtBr resistance. We identified genes required for the growth of L. biflexa in the presence of sublethal EtBr concentration and characterized their potential as antibiotic resistance determinants. This study will help to delineate mechanisms of adaptation to toxic compounds, as well as potential mechanisms of antibiotic resistance development in pathogenic L. interrogans.
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Anwar MA, Choi S. Gram-negative marine bacteria: structural features of lipopolysaccharides and their relevance for economically important diseases. Mar Drugs 2014; 12:2485-514. [PMID: 24796306 PMCID: PMC4052302 DOI: 10.3390/md12052485] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 03/03/2014] [Accepted: 04/08/2014] [Indexed: 11/17/2022] Open
Abstract
Gram-negative marine bacteria can thrive in harsh oceanic conditions, partly because of the structural diversity of the cell wall and its components, particularly lipopolysaccharide (LPS). LPS is composed of three main parts, an O-antigen, lipid A, and a core region, all of which display immense structural variations among different bacterial species. These components not only provide cell integrity but also elicit an immune response in the host, which ranges from other marine organisms to humans. Toll-like receptor 4 and its homologs are the dedicated receptors that detect LPS and trigger the immune system to respond, often causing a wide variety of inflammatory diseases and even death. This review describes the structural organization of selected LPSes and their association with economically important diseases in marine organisms. In addition, the potential therapeutic use of LPS as an immune adjuvant in different diseases is highlighted.
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Affiliation(s)
- Muhammad Ayaz Anwar
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea.
| | - Sangdun Choi
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea.
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31
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Sterile-α- and armadillo motif-containing protein inhibits the TRIF-dependent downregulation of signal regulatory protein α to interfere with intracellular bacterial elimination in Burkholderia pseudomallei-infected mouse macrophages. Infect Immun 2013; 81:3463-71. [PMID: 23836818 DOI: 10.1128/iai.00519-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, evades macrophage killing by suppressing the TRIF-dependent pathway, leading to inhibition of inducible nitric oxide synthase (iNOS) expression. We previously demonstrated that virulent wild-type B. pseudomallei inhibits the TRIF-dependent pathway by upregulating sterile-α- and armadillo motif-containing protein (SARM) and by inhibiting downregulation of signal regulatory protein α (SIRPα); both molecules are negative regulators of Toll-like receptor signaling. In contrast, the less virulent lipopolysaccharide (LPS) mutant of B. pseudomallei is unable to exhibit these features and is susceptible to macrophage killing. However, the functional relationship of these two negative regulators in the evasion of macrophage defense has not been elucidated. We demonstrated here that SIRPα downregulation was observed after inhibition of SARM expression by small interfering RNA in wild-type-infected macrophages, indicating that SIRPα downregulation is regulated by SARM. Furthermore, this downregulation requires activation of the TRIF signaling pathway, as we observed abrogation of SIRPα downregulation as well as restricted bacterial growth in LPS mutant-infected TRIF-depleted macrophages. Although inhibition of SARM expression is correlated to SIRPα downregulation and iNOS upregulation in gamma interferon-activated wild-type-infected macrophages, these phenomena appear to bypass the TRIF-dependent pathway. Similar to live bacteria, the wild-type LPS is able to upregulate SARM and to prevent SIRPα downregulation, implying that the LPS of B. pseudomallei may play a crucial role in regulating the expression of these two negative regulators. Altogether, our findings show a previously unrecognized role of B. pseudomallei-induced SARM in inhibiting SIRPα downregulation-mediated iNOS upregulation, facilitating the ability of the bacterium to multiply in macrophages.
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Yuan B, Cheng A, Wang M. Polysaccharide export outer membrane proteins in Gram-negative bacteria. Future Microbiol 2013; 8:525-35. [DOI: 10.2217/fmb.13.13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Polysaccharide export outer membrane proteins of Gram-negative bacteria are involved in the export of polysaccharides across the outer membrane. The mechanisms of polysaccharide export across the outer membrane in Gram-negative bacteria are not yet completely clear. However, the mechanisms of polysaccharide assembly in Escherichia coli have been intensively investigated. Here, we mainly review the current understanding of the assembly mechanisms of group 1 capsular polysaccharide, group 2 capsular polysaccharide and lipopolysaccharide of E. coli, and the current structures and interactions of some polysaccharide export outer membrane proteins with other proteins involved in polysaccharide export in Gram-negative bacteria. In addition, LptD may be targeted by peptidomimetic antibiotics in Gram-negative bacteria. We also give insights into the directions of future research regarding the mechanisms of polysaccharide export.
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Affiliation(s)
- Biao Yuan
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46 Xinkang Road, Ya’an, Sichuan 625014, China
- Key Laboratory of Animal Disease & Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu city, Sichuan 611130, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46 Xinkang Road, Ya’an, Sichuan 625014, China
- Key Laboratory of Animal Disease & Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu city, Sichuan 611130, China
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Defects in D-rhamnosyl residue biosynthetic genes affect lipopolysaccharide structure, motility, and cell-surface hydrophobicity in Pseudomonas syringae pathovar glycinea race 4. Biosci Biotechnol Biochem 2013; 77:505-10. [PMID: 23470736 DOI: 10.1271/bbb.120736] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
D-rhamnose (D-Rha) residue is a major component of lipopolysaccharides (LPSs) in strains of the phytopathogen Pseudomonas syringae pathovar glycinea. To investigate the effects of a deficiency in GDP-D-rhamnose biosynthetic genes on LPS structure and pathogenicity, we generated three mutants defective in D-Rha biosynthetic genes, encoding proteins GDP-D-mannose 4,6-dehydratase (GMD), GDP-4-keto-6-deoxy-D-mannose reductase (RMD), and a putative α-D-rhamnosyltransferase (WbpZ) in P. syringae pv. glycinea race 4. The Δgmd, Δrmd, and ΔwbpZ mutants had a reduced O-antigen polysaccharide consisting of D-Rha residues as compared with the wild type (WT). The swarming motility of the Δgmd, Δrmd, and ΔwbpZ mutant strains decreased and hydrophobicity and adhesion ability increased as compared with WT. Although the mutants had truncated O-antigen polysaccharides, and altered surface properties, they showed virulence to soybean, as WT did.
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Robinson JA. Max Bergmann lecture protein epitope mimetics in the age of structural vaccinology. J Pept Sci 2013; 19:127-40. [PMID: 23349031 PMCID: PMC3592999 DOI: 10.1002/psc.2482] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 11/09/2022]
Abstract
This review highlights the growing importance of protein epitope mimetics in the discovery of new biologically active molecules and their potential applications in drug and vaccine research. The focus is on folded β-hairpin mimetics, which are designed to mimic β-hairpin motifs in biologically important peptides and proteins. An ever-growing number of protein crystal structures reveal how β-hairpin motifs often play key roles in protein-protein and protein-nucleic acid interactions. This review illustrates how using protein structures as a starting point for small-molecule mimetic design can provide novel ligands as protein-protein interaction inhibitors, as protease inhibitors, and as ligands for chemokine receptors and folded RNA targets, as well as novel antibiotics to combat the growing health threat posed by the emergence of antibiotic-resistant bacteria. The β-hairpin antibiotics are shown to target a β-barrel outer membrane protein (LptD) in Pseudomonas sp., which is essential for the biogenesis of the outer cell membrane. Another exciting prospect is that protein epitope mimetics will be of increasing importance in synthetic vaccine design, in the emerging field of structural vaccinology. Crystal structures of protective antibodies bound to their pathogen-derived epitopes provide an ideal starting point for the design of synthetic epitope mimetics. The mimetics can be delivered to the immune system in a highly immunogenic format on the surface of synthetic virus-like particles. The scientific challenges in molecular design remain great, but the potential significance of success in this area is even greater.
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Affiliation(s)
- John A Robinson
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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35
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Kilár A, Dörnyei Á, Kocsis B. Structural characterization of bacterial lipopolysaccharides with mass spectrometry and on- and off-line separation techniques. MASS SPECTROMETRY REVIEWS 2013; 32:90-117. [PMID: 23165926 DOI: 10.1002/mas.21352] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 03/27/2012] [Accepted: 03/27/2012] [Indexed: 06/01/2023]
Abstract
The focus of this review is the application of mass spectrometry to the structural characterization of bacterial lipopolysaccharides (LPSs), also referred to as "endotoxins," because they elicit the strong immune response in infected organisms. Recently, a wide variety of MS-based applications have been implemented to the structure elucidation of LPS. Methodological improvements, as well as on- and off-line separation procedures, proved the versatility of mass spectrometry to study complex LPS mixtures. Special attention is given in the review to the tandem mass spectrometric methods and protocols for the analyses of lipid A, the endotoxic principle of LPS. We compare and evaluate the different ionization techniques (MALDI, ESI) in view of their use in intact R- and S-type LPS and lipid A studies. Methods for sample preparation of LPS prior to mass spectrometric analysis are also described. The direct identification of intrinsic heterogeneities of most intact LPS and lipid A preparations is a particular challenge, for which separation techniques (e.g., TLC, slab-PAGE, CE, GC, HPLC) combined with mass spectrometry are often necessary. A brief summary of these combined methodologies to profile LPS molecular species is provided.
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Affiliation(s)
- Anikó Kilár
- Department of Analytical and Environmental Chemistry, Institute of Chemistry, Faculty of Sciences, University of Pécs, Pécs, Hungary.
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36
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Kabanov DS, Prokhorenko IR. Involvement of Toll-like receptor 4 and Fc receptors gamma in human neutrophil priming by endotoxins from Escherichia coli. BIOCHEMISTRY (MOSCOW) 2013; 78:185-93. [DOI: 10.1134/s0006297913020077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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37
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Barjesteh N, Hodgins DC, St Paul M, Quinteiro-Filho WM, DePass C, Monteiro MA, Sharif S. Induction of chicken cytokine responses in vivo and in vitro by lipooligosaccharide of Campylobacter jejuni HS:10. Vet Microbiol 2013; 164:122-30. [PMID: 23473646 DOI: 10.1016/j.vetmic.2013.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/30/2013] [Accepted: 02/07/2013] [Indexed: 12/12/2022]
Abstract
Campylobacter jejuni is a pathogen of the gastrointestinal tract of humans, but colonizes chickens for prolonged periods without causing disease. It is unclear what host and bacterial mechanisms maintain a non-inflammatory state in chickens. The present work was undertaken to characterize cytokine responses of chickens to purified lipooligosaccharide (LOS) of C. jejuni HS:10. Chickens were injected with purified LOS, and expression of interleukin (IL)-1β (pro-inflammatory cytokine), IL-8 (pro-inflammatory chemokine), interferon (IFN)γ (Th1-like cytokine), IL-10 (immune regulatory/anti-inflammatory cytokine) and IL-13 (Th2-like cytokine) was evaluated in spleen using quantitative RT-PCR, up to 24h post-injection. In an in vitro study, splenocytes were incubated with LOS, and cytokine expression followed up to 18 h. Chickens injected with LOS had increased expression of IL-1β up to 24h later. Expression of IL-8 was significantly increased at 2h but then declined below baseline. Expression of IFNγ and IL-10 was increased significantly at 2h, but declined thereafter. Splenocytes incubated with LOS had increased expression of IL-1β and IL-8 up to 18 h of incubation. Expression of IFNγ was increased at 6 and 18 h, IL-10 was increased at 2h, but expression of IL-13 did not differ significantly up to 18h. It is concluded that LOS of C. jejuni can induce expression of pro-inflammatory IL-1β and IL-8, as well as IFNγ and IL-10 in chickens. More extensive studies with more prolonged exposure to LOS are needed to further clarify the interaction between C. jejuni and the chicken host.
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Affiliation(s)
- Neda Barjesteh
- Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada
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OGISO M, AIBA SI, MINOURA N. Preparation of Molecularly Imprinted Polymer Gel Beads for Adsorption of Endotoxin. KOBUNSHI RONBUNSHU 2013. [DOI: 10.1295/koron.70.82] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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39
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Werneburg M, Zerbe K, Juhas M, Bigler L, Stalder U, Kaech A, Ziegler U, Obrecht D, Eberl L, Robinson JA. Inhibition of lipopolysaccharide transport to the outer membrane in Pseudomonas aeruginosa by peptidomimetic antibiotics. Chembiochem 2012; 13:1767-75. [PMID: 22807320 DOI: 10.1002/cbic.201200276] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Indexed: 11/08/2022]
Abstract
The asymmetric outer membrane (OM) of Gram-negative bacteria contains lipopolysaccharide (LPS) in the outer leaflet and phospholipid in the inner leaflet. During OM biogenesis, LPS is transported from the periplasm into the outer leaflet by a complex comprising the OM proteins LptD and LptE. Recently, a new family of macrocyclic peptidomimetic antibiotics that interact with LptD of the opportunistic human pathogen Pseudomonas aeruginosa was discovered. Here we provide evidence that the peptidomimetics inhibit the LPS transport function of LptD. One approach to monitor LPS transport involved studies of lipid A modifications. Some modifications occur only in the inner membrane while others occur only in the OM, and thus provide markers for LPS transport within the bacterial envelope. We prepared a conditional lptD mutant of P. aeruginosa PAO1 that allowed control of lptD expression from the rhamnose promoter. With this mutant, the effects caused by the antibiotic on the wild-type strain were compared with those caused by depleting LptD in the mutant strain. When LptD was depleted in the mutant, electron microscopy revealed accumulation of membrane-like material within cells and OM blebbing; this mirrored similar effects in the wild-type strain caused by the antibiotic. Moreover, the bacterium responded to the antibiotic, and to depletion of LptD, by introducing the same lipid A modifications, consistent with inhibition by the antibiotic of LptD-mediated LPS transport. This conclusion was further supported by monitoring the radiolabelling of LPS from [¹⁴C]acetate, and by fractionation of IM and OM components. Overall, the results provide support for a mechanism of action for the peptidomimetic antibiotics that involves inhibition of LPS transport to the cell surface.
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Affiliation(s)
- Martina Werneburg
- Chemistry Department, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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Lipopolysaccharides: from Erinyes to Charites. Mediators Inflamm 2012; 2012:684274. [PMID: 22665953 PMCID: PMC3361297 DOI: 10.1155/2012/684274] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 02/26/2012] [Indexed: 01/22/2023] Open
Abstract
Following the discovery of endotoxins by Richard Pfeiffer, such bacterial product was associated to many severe disorders produced by an overwhelming inflammatory response and often resulting in endotoxic shock and multiple organ failure. However, recent clinical and basic sciences investigations claimed some beneficial roles of typical as well as atypical endotoxins. The aim of this paper is to focus on recent data supporting a beneficial activity of both typical and atypical endotoxins. Such novel perspective looks promising for development of new drugs for prevention and therapy of several human diseases.
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Mutschler H, Meinhart A. ε/ζ systems: their role in resistance, virulence, and their potential for antibiotic development. J Mol Med (Berl) 2011; 89:1183-94. [PMID: 21822621 PMCID: PMC3218275 DOI: 10.1007/s00109-011-0797-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 07/19/2011] [Accepted: 07/22/2011] [Indexed: 12/17/2022]
Abstract
Cell death in bacteria can be triggered by activation of self-inflicted molecular mechanisms. Pathogenic bacteria often make use of suicide mechanisms in which the death of individual cells benefits survival of the population. Important elements for programmed cell death in bacteria are proteinaceous toxin-antitoxin systems. While the toxin generally resides dormant in the bacterial cytosol in complex with its antitoxin, conditions such as impaired de novo synthesis of the antitoxin or nutritional stress lead to antitoxin degradation and toxin activation. A widespread toxin-antitoxin family consists of the ε/ζ systems, which are distributed over plasmids and chromosomes of various pathogenic bacteria. In its inactive state, the bacteriotoxic ζ toxin protein is inhibited by its cognate antitoxin ε. Upon degradation of ε, the ζ toxin is released allowing this enzyme to poison bacterial cell wall synthesis, which eventually triggers autolysis. ε/ζ systems ensure stable plasmid inheritance by inducing death in plasmid-deprived offspring cells. In contrast, chromosomally encoded ε/ζ systems were reported to contribute to virulence of pathogenic bacteria, possibly by inducing autolysis in individual cells under stressful conditions. The capability of toxin-antitoxin systems to kill bacteria has made them potential targets for new therapeutic compounds. Toxin activation could be hijacked to induce suicide of bacteria. Likewise, the unique mechanism of ζ toxins could serve as template for new drugs. Contrarily, inhibition of virulence-associated ζ toxins might attenuate infections. Here we provide an overview of ε/ζ toxin-antitoxin family and its potential role in the development of new therapeutic approaches in microbial defense.
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Affiliation(s)
- Hannes Mutschler
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Heidelberg, Germany
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Emerging New Therapeutics Against Key Gram-Negative Pathogens. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2011. [DOI: 10.1016/b978-0-12-386009-5.00012-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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