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Wu J, Jiang L, Shao Q, Liu J, Wang H, Gao Q, Huan C, Wang X, Gao S. Comparison of the safety and efficacy of the wild-type and lpxL/lpxM mutant inactivated vaccine against the avian pathogenic Escherichia coli O1, O2, and O78 challenge. Vaccine 2024; 42:2707-2715. [PMID: 38503663 DOI: 10.1016/j.vaccine.2024.03.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 03/21/2024]
Abstract
Avian pathogenic Escherichia coli (APEC) is primarily responsible for causing septicemia, pneumonitis, peritonitis, swollen head syndrome, and salpingitis in poultry, leading to significant losses in the poultry sector, particularly within the broiler industry. The removal of the lpxL and lpxM genes led to an eightfold decrease in the endotoxin levels of wild APEC strains. In this study, mutant strains of lpxL/lpxM and their O1, O2, and O78 wild-type strains were developed for an inactivated vaccine (referred to as the mutant vaccine and the wild-type vaccine, respectively), and the safety and effectiveness of these two prototype vaccines were assessed in white Leghorn chickens. Findings indicated that chickens immunized with the mutant vaccine showed a return of appetite sooner post-immunization and experienced earlier disappearance of nodules at the injection site compared to those immunized with the wild-type vaccine. Pathological examinations revealed that lesions were still present in the liver, lung, and injection site in chickens vaccinated with the wild-type vaccine 14 days post-vaccination (dpv), whereas no lesions were found in chickens vaccinated with the mutant vaccine at 14 dpv. There were no significant differences in antibody levels on the challenge day or in mortality or lesion scores between challenged birds immunized with either the mutant vaccine or the wild-type vaccine at the same dose. In this study, the safety of a single dose or overdose of the mutant vaccine and its efficacy at one dose were evaluated in broilers, and the results showed that the mutant vaccine had no adverse effects on or protected vaccinated broilers from challenge with the APEC O1, O2, or O78 strains. These results demonstrated that the mutant polyvalent inactivated vaccine is a competitive candidate against APEC O1, O2, and O78 infection compared to the wild-type vaccine.
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Affiliation(s)
- Jiayan Wu
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Luyao Jiang
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Qiwen Shao
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Juanhua Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Hang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Qingqing Gao
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Changchao Huan
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Xiaobo Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China
| | - Song Gao
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, Jiangsu, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou 225009, Jiangsu, China; Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou 225009, Jiangsu, China.
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Hu Z, Bai X. Self-repair and resuscitation of viable injured bacteria in chlorinated drinking water: Achromobacter as an example. WATER RESEARCH 2023; 245:120585. [PMID: 37690414 DOI: 10.1016/j.watres.2023.120585] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/24/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023]
Abstract
Chlorine disinfection for the treatment of drinking water can cause injury to the membrane and DNA of bacterial cells and may induce the surviving injured bacteria into a viable but non-culturable (VBNC) state. It is difficult to monitor viable injured bacteria by heterotrophic plate counting (HPC), and their presence is also easily miscalculated in flow cytometry intact cell counting (FCM-ICC). Viable injured bacteria have a potential risk of resuscitation in drinking water distribution systems (DWDSs) and pose a threat to public health when drinking from faucets. In this study, bacteria with injured membranes were isolated from chlorinated drinking water by FCM cell sorting. The culture rate of injured bacteria varied from 0.08% to 2.6% on agar plates and 0.39% to 6.5% in 96-well plates. As the dominant genus among the five identified genera, as well as an opportunistic pathogen with multiple antibiotic resistance, Achromobacter was selected and further studied. After treatment with chlorine at a concentration of 1.2 mg/L, Achromobacter entered into the intermediate injured state on the FCM plot, and the injury on the bacterial surface was observed by electron microscopy. However, the CTC respiratory activity assay showed that 75.0% of the bacteria were still physiologically active, and they entered into a VBNC state. The injured VBNC Achromobacter in sterile drinking water were resuscitated after approximately 25 h. The cellular repair behavior of injured bacteria was studied by Fourier transform infrared attenuated total reflectance (FTIR-ATR) and comet assays. It was found that DNA injury rather than membrane injury was repaired first. The expression of Ku and ligD increased significantly during the DNA repair period, indicating that non-homologous end-joining (NHEJ) played an important role in repairing DNA double-strand breaks. This study deepened the understanding of the effect of chlorine disinfection on bacterial viability in drinking water and will provide support for the improvement of the chlorine disinfection process for the treatment of drinking water.
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Affiliation(s)
- Zengyi Hu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaohui Bai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
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Puelles JS, Ghorbani M, Tuck B, Machuca LL, Ackland ML, Chen F, Somers AE, Forsyth M. Effect of cetrimonium carrier micelles on bacterial membranes and extracellular DNA, an in silico study. Sci Rep 2023; 13:8041. [PMID: 37198168 DOI: 10.1038/s41598-023-32475-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 03/28/2023] [Indexed: 05/19/2023] Open
Abstract
Microorganisms do not live as dispersed single cells but rather they form aggregates with extracellular polymeric substances at interfaces. Biofilms are considered efficient life forms because they shield bacteria from biocides and collect dilute nutrients. This is a big concern in industry since the microorganisms can colonize a wide range of surfaces, accelerating material deterioration, colonizing medical devices, contaminating ultrapure drinking water, increasing energy costs and creating focus of infection. Conventional biocides that target a specific component of the bacteria are not effective in the presence of biofilms. Efficient biofilm inhibitors are based on a multitarget approach interacting with the bacteria and the biofilm matrix. Their rationale design requires a thorough understanding of inhibitory mechanisms that are still largely lacking today. Herein we uncover via molecular modelling the inhibition mechanism of cetrimonium 4-OH cinnamate (CTA-4OHcinn). Simulations show that CTA-4OH micelles can disrupt symmetric and asymmetric bilayers, representative of inner and outer bacterial membranes, following three stages: adsorption, assimilation, and defect formation. The main driving force for micellar attack is electrostatic interactions. In addition to disrupting the bilayers, the micelles work as carriers facilitating the trapping of 4OH cinnamate anions within the bilayer upper leaflet and overcoming electrostatic repulsion. The micelles also interact with extracellular DNA (e-DNA), which is one of the main components of biofilms. It is observed that CTA-4OHcinn forms spherical micelles on the DNA backbone; which hinders their ability to pack. This is demonstrated by modelling the DNA along the hbb histone-like protein, showing that in the presence of CTA-4OHcinn, DNA does not pack properly around hbb. The abilities of CTA-4OHcinn to cause cell death through membrane disruption and to disperse a mature, multi-species biofilm are also confirmed experimentally.
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Affiliation(s)
| | - Mahdi Ghorbani
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia
| | - Benjamin Tuck
- Curtin Corrosion Centre, WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Kent Street, Bentley, WA, 6102, Australia
| | - Laura L Machuca
- Curtin Corrosion Centre, WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Kent Street, Bentley, WA, 6102, Australia
| | - M Leigh Ackland
- ARC Centre of Excellence for Electromaterials Science (ACES), Deakin University, Burwood, 3125, Australia
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, 3125, Australia
| | - Fangfang Chen
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia.
- ARC Centre of Excellence for Electromaterials Science (ACES), Deakin University, Burwood, 3125, Australia.
| | - Anthony E Somers
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia.
| | - Maria Forsyth
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia.
- ARC Centre of Excellence for Electromaterials Science (ACES), Deakin University, Burwood, 3125, Australia.
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Romano K, Hung D. Targeting LPS biosynthesis and transport in gram-negative bacteria in the era of multi-drug resistance. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119407. [PMID: 36543281 PMCID: PMC9922520 DOI: 10.1016/j.bbamcr.2022.119407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/23/2022]
Abstract
Gram-negative bacteria pose a major threat to human health in an era fraught with multi-drug resistant bacterial infections. Despite extensive drug discovery campaigns over the past decades, no new antibiotic target class effective against gram-negative bacteria has become available to patients since the advent of the carbapenems in 1985. Antibiotic discovery efforts against gram-negative bacteria have been hampered by limited intracellular accumulation of xenobiotics, in large part due to the impermeable cell envelope comprising lipopolysaccharide (LPS) in the outer leaflet of the outer membrane, as well as a panoply of efflux pumps. The biosynthesis and transport of LPS are essential to the viability and virulence of most gram-negative bacteria. Thus, both LPS biosynthesis and transport are attractive pathways to target therapeutically. In this review, we summarize the LPS biosynthesis and transport pathways and discuss efforts to find small molecule inhibitors against targets within these pathways.
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Affiliation(s)
- K.P. Romano
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Boston, MA, USA,The Broad Institute of MIT and Harvard, Cambridge, MA, USA,Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA
| | - D.T. Hung
- The Broad Institute of MIT and Harvard, Cambridge, MA, USA,Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA,Department of Genetics, Harvard Medical School, Boston, MA, USA,Corresponding author at: The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (D.T. Hung)
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Ryu S, Ni K, Wang C, Sivanantham A, Carnino JM, Ji HL, Jin Y. Bacterial Outer Membrane Vesicles Promote Lung Inflammatory Responses and Macrophage Activation via Multi-Signaling Pathways. Biomedicines 2023; 11:568. [PMID: 36831104 PMCID: PMC9953134 DOI: 10.3390/biomedicines11020568] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Emerging evidence suggests that Gram-negative bacteria release bacterial outer membrane vesicles (OMVs) and that these play an important role in the pathogenesis of bacterial infection-mediated inflammatory responses and organ damage. Despite the fact that scattered reports have shown that OMVs released from Gram-negative bacteria may function via the TLR2/4-signaling pathway or induce pyroptosis in macrophages, our study reveals a more complex role of OMVs in the development of inflammatory lung responses and macrophage pro-inflammatory activation. We first confirmed that various types of Gram-negative bacteria release similar OMVs which prompt pro-inflammatory activation in both bone marrow-derived macrophages and lung alveolar macrophages. We further demonstrated that mice treated with OMVs via intratracheal instillation developed significant inflammatory lung responses. Using mouse inflammation and autoimmune arrays, we identified multiple altered cytokine/chemokines in both bone marrow-derived macrophages and alveolar macrophages, suggesting that OMVs have a broader spectrum of function compared to LPS. Using TLR4 knock-out cells, we found that OMVs exert more robust effects on activating macrophages compared to LPS. We next examined multiple signaling pathways, including not only cell surface antigens, but also intracellular receptors. Our results confirmed that bacterial OMVs trigger both surface protein-mediated signaling and intracellular signaling pathways, such as the S100-A8 protein-mediated pathway. In summary, our studies confirm that bacterial OMVs strongly induced macrophage pro-inflammatory activation and inflammatory lung responses via multi-signaling pathways. Bacterial OMVs should be viewed as a repertoire of pathogen-associated molecular patterns (PAMPs), exerting more robust effects than Gram-negative bacteria-derived LPS.
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Affiliation(s)
- Sunhyo Ryu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Boston University, Boston, MA 02118, USA
| | - Kareemah Ni
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Boston University, Boston, MA 02118, USA
| | - Chenghao Wang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Boston University, Boston, MA 02118, USA
| | - Ayyanar Sivanantham
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Boston University, Boston, MA 02118, USA
| | - Jonathan M. Carnino
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Boston University, Boston, MA 02118, USA
| | - Hong-Long Ji
- Department of Cellular and Molecular Biology, University of Texas at Tyler Health Science Center, 11937 US Hwy 271, BMR, Lab D-11, Tyler, TX 75708, USA
| | - Yang Jin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Boston University, Boston, MA 02118, USA
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Afonnikova S, Komissarov A, Kuchur P. Unique or not unique? Comparative genetic analysis of bacterial O-antigens from the Oxalobacteraceae family. Vavilovskii Zhurnal Genet Selektsii 2022; 26:810-818. [PMID: 36694719 PMCID: PMC9834719 DOI: 10.18699/vjgb-22-98] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/10/2022] [Accepted: 10/26/2022] [Indexed: 01/06/2023] Open
Abstract
Many plants and animals have symbiotic relationships with microorganisms, including bacteria. The interactions between bacteria and their hosts result in different outcomes for the host organism. The outcome can be neutral, harmful or have beneficial effects for participants. Remarkably, these relationships are not static, as they change throughout an organism's lifetime and on an evolutionary scale. One of the structures responsible for relationships in bacteria is O-antigen. Depending on the characteristics of its components, the bacteria can avoid the host's immune response or establish a mutualistic relationship with it. O-antigen is a key component in Gram-negative bacteria's outer membrane. This component facilitates interaction between the bacteria and host immune system or phages. The variability of the physical structure is caused by the genomic variability of genes encoding O-antigen synthesis components. The genes and pathways of O-polysaccharide (OPS) synthesis were intensively investigated mostly for Enterobacteriaceae species. Considering high genetic and molecular diversity of this structure even between strains, these findings may not have caught the entire variety possibly presented in non-model species. The current study presents a comparative analysis of genes associated with O-antigen synthesis in bacteria of the Oxalobacteraceae family. In contrast to existing studies based on PCR methods, we use a bioinformatics approach and compare O- antigens at the level of clusters rather than individual genes. We found that the O-antigen genes of these bacteria are represented by several clusters located at a distance from each other. The greatest similarity of the clusters is observed within individual bacterial genera, which is explained by the high variability of O-antigens. The study describes similarities of OPS genes inherent to the family as a whole and also considers individual unique cases of O-antigen genetic variability inherent to individual bacteria.
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Affiliation(s)
- S.D. Afonnikova
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, RussiaNovosibirsk State University, Novosibirsk, Russia
| | | | - P.D. Kuchur
- ITMO University, SCAMT Institute, St. Petersburg, Russia
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Dong Y, Wang P, Yang X, Chen M, Li J. Potential of gut microbiota for lipopolysaccharide biosynthesis in European women with type 2 diabetes based on metagenome. Front Cell Dev Biol 2022; 10:1027413. [PMID: 36303603 PMCID: PMC9592851 DOI: 10.3389/fcell.2022.1027413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 09/27/2022] [Indexed: 11/16/2022] Open
Abstract
The abnormal accumulation of lipopolysaccharide (LPS) plays a crucial role in promoting type 2 diabetes (T2D). However, the capability of the gut microbiota to produce LPS in patients with T2D is still unclear, and evidence characterizing the patterns of gut microbiota with LPS productivity remains rare. This study aimed to uncover the profiles of LPS-biosynthesis-related enzymes and pathways, and explore the potential of LPS-producing gut microbiota in T2D. The gut metagenomic sequencing data from a European female cohort with normal glucose tolerance or untreated T2D were analyzed in this study. The sequence search revealed that the relative abundance of the critical enzymes responsible for LPS biosynthesis was significantly high in patients with T2D, especially for N-acetylglucosamine deacetylase, 3-deoxy-D-manno-octulosonic-acid transferase, and lauroyl-Kdo2-lipid IVA myristoyltransferase. The functional analysis indicated that a majority of pathways involved in LPS biosynthesis were augmented in patients with T2D. A total of 1,173 species from 335 genera containing the gene sequences of LPS enzymes, including LpxA/B/C/D/H/K/L/M and/or WaaA, coexisted in controls and patients with T2D. Critical taxonomies with discriminative fecal abundance between groups were revealed, which exhibited different associations with enzymes. Moreover, the identified gut microbial markers had correlations with LPS enzymes and were subsequently associated with microbial pathways. The present findings delineated the potential capability of gut microbiota toward LPS biosynthesis in European women and highlighted a gut microbiota−based mechanistic link between the disturbance in LPS biosynthesis and T2D. The restoration of LPS levels through gut microbiota manipulation might offer potential approaches for preventing and treating T2D.
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Samet S, Ayachi A, Fourati M, Mallouli L, Allouche N, Treilhou M, Téné N, Mezghani-Jarraya R. Antioxidant and Antimicrobial Activities of Erodium arborescens Aerial Part Extracts and Characterization by LC-HESI-MS 2 of Its Acetone Extract. Molecules 2022; 27:molecules27144399. [PMID: 35889269 PMCID: PMC9318634 DOI: 10.3390/molecules27144399] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/20/2022] [Accepted: 07/05/2022] [Indexed: 11/24/2022] Open
Abstract
The phytochemical analysis of antioxidant and antibacterial activities of Erodium arborescens aerial part extracts constitute the focus of this research. The chemical composition of an acetone extract was investigated using LC-HESI-MS2, which revealed the presence of 70 compounds. The major identified components were tannin derivatives. Total polyphenol and total flavonoid contents were assessed in plant extracts (hexane, ethyl acetate, acetone and methanol). The results showed that the acetone extract exhibited the highest contents of polyphenols and flavonoids, 895.54 and 36.39 mg QE/g DE, respectively. Furthermore, when compared to other extracts, Erodium arborescens acetone extract was endowed with the highest antioxidant activity with 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) tests. In addition, the four extracts of Erodium arborescens showed variable degrees of antimicrobial activity against the tested strains, and the interesting activity was obtained with acetone and methanol extracts.
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Affiliation(s)
- Sonda Samet
- Laboratory of Organic Chemistry LR17ES08, Natural Substances Team, Faculty of Sciences of Sfax, University of Sfax, P.B. 1171, Sfax 3000, Tunisia; (S.S.); (A.A.); (N.A.); (R.M.-J.)
| | - Amani Ayachi
- Laboratory of Organic Chemistry LR17ES08, Natural Substances Team, Faculty of Sciences of Sfax, University of Sfax, P.B. 1171, Sfax 3000, Tunisia; (S.S.); (A.A.); (N.A.); (R.M.-J.)
| | - Mariam Fourati
- Laboratory of Microbial Biotechnology and Enzyme Engineering of the Center of Biotechnology of Sfax, University of Sfax-Tunisia, Road of Sidi Mansour Km 6, P.B. 1177, Sfax 3018, Tunisia; (M.F.); (L.M.)
| | - Lotfi Mallouli
- Laboratory of Microbial Biotechnology and Enzyme Engineering of the Center of Biotechnology of Sfax, University of Sfax-Tunisia, Road of Sidi Mansour Km 6, P.B. 1177, Sfax 3018, Tunisia; (M.F.); (L.M.)
| | - Noureddine Allouche
- Laboratory of Organic Chemistry LR17ES08, Natural Substances Team, Faculty of Sciences of Sfax, University of Sfax, P.B. 1171, Sfax 3000, Tunisia; (S.S.); (A.A.); (N.A.); (R.M.-J.)
| | - Michel Treilhou
- Equipe BTSB-EA 7417, Institut National Universitaire Jean-François Champollion, Université de Toulouse, Place de Verdun, 81012 Albi, France;
| | - Nathan Téné
- Equipe BTSB-EA 7417, Institut National Universitaire Jean-François Champollion, Université de Toulouse, Place de Verdun, 81012 Albi, France;
- Correspondence: ; Tel.: +33-667276471
| | - Raoudha Mezghani-Jarraya
- Laboratory of Organic Chemistry LR17ES08, Natural Substances Team, Faculty of Sciences of Sfax, University of Sfax, P.B. 1171, Sfax 3000, Tunisia; (S.S.); (A.A.); (N.A.); (R.M.-J.)
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Influence of emulsified plant oil composition on growth and biopolymer production of Cupriavidus necator DSM 545. FOOD AND BIOPRODUCTS PROCESSING 2022. [DOI: 10.1016/j.fbp.2021.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Malishev R, Salinas N, Gibson J, Eden AB, Mieres-Perez J, Ruiz-Blanco YB, Malka O, Kolusheva S, Klärner FG, Schrader T, Sanchez-Garcia E, Wang C, Landau M, Bitan G, Jelinek R. Inhibition of Staphylococcus aureus biofilm-forming functional amyloid by molecular tweezers. Cell Chem Biol 2021; 28:1310-1320.e5. [PMID: 33852903 DOI: 10.1016/j.chembiol.2021.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/19/2021] [Accepted: 03/19/2021] [Indexed: 02/07/2023]
Abstract
Biofilms are rigid and largely impenetrable three-dimensional matrices constituting virulence determinants of various pathogenic bacteria. Here, we demonstrate that molecular tweezers, unique supramolecular artificial receptors, modulate biofilm formation of Staphylococcus aureus. In particular, the tweezers affect the structural and assembly properties of phenol-soluble modulin α1 (PSMα1), a biofilm-scaffolding functional amyloid peptide secreted by S. aureus. The data reveal that CLR01, a diphosphate tweezer, exhibits significant S. aureus biofilm inhibition and disrupts PSMα1 self-assembly and fibrillation, likely through inclusion of lysine side chains of the peptide. In comparison, different peptide binding occurs in the case of CLR05, a tweezer containing methylenecarboxylate units, which exhibits lower affinity for the lysine residues yet disrupts S. aureus biofilm more strongly than CLR01. Our study points to a possible role for molecular tweezers as potent biofilm inhibitors and antibacterial agents, particularly against untreatable biofilm-forming and PSM-producing bacteria, such as methicillin-resistant S. aureus.
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Affiliation(s)
- Ravit Malishev
- Department of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Nir Salinas
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - James Gibson
- Center for Biotechnology and Interdisciplinary Studies, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Angela Bailey Eden
- Center for Biotechnology and Interdisciplinary Studies, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Joel Mieres-Perez
- Department of Computational Biochemistry, University of Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany
| | - Yasser B Ruiz-Blanco
- Department of Computational Biochemistry, University of Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany
| | - Orit Malka
- Department of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Sofiya Kolusheva
- Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | | | - Thomas Schrader
- Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany
| | - Elsa Sanchez-Garcia
- Department of Computational Biochemistry, University of Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany
| | - Chunyu Wang
- Center for Biotechnology and Interdisciplinary Studies, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Meytal Landau
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel; European Molecular Biology Laboratory (EMBL), 22607 Hamburg, Germany
| | - Gal Bitan
- Department of Neurology, David Geffen School of Medicine, Brain Research Institute, and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Raz Jelinek
- Department of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel; Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel.
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Nardi P, Laanbroek HJ, Nicol GW, Renella G, Cardinale M, Pietramellara G, Weckwerth W, Trinchera A, Ghatak A, Nannipieri P. Biological nitrification inhibition in the rhizosphere: determining interactions and impact on microbially mediated processes and potential applications. FEMS Microbiol Rev 2021; 44:874-908. [PMID: 32785584 DOI: 10.1093/femsre/fuaa037] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 08/10/2020] [Indexed: 12/11/2022] Open
Abstract
Nitrification is the microbial conversion of reduced forms of nitrogen (N) to nitrate (NO3-), and in fertilized soils it can lead to substantial N losses via NO3- leaching or nitrous oxide (N2O) production. To limit such problems, synthetic nitrification inhibitors have been applied but their performance differs between soils. In recent years, there has been an increasing interest in the occurrence of biological nitrification inhibition (BNI), a natural phenomenon according to which certain plants can inhibit nitrification through the release of active compounds in root exudates. Here, we synthesize the current state of research but also unravel knowledge gaps in the field. The nitrification process is discussed considering recent discoveries in genomics, biochemistry and ecology of nitrifiers. Secondly, we focus on the 'where' and 'how' of BNI. The N transformations and their interconnections as they occur in, and are affected by, the rhizosphere, are also discussed. The NH4+ and NO3- retention pathways alternative to BNI are reviewed as well. We also provide hypotheses on how plant compounds with putative BNI ability can reach their targets inside the cell and inhibit ammonia oxidation. Finally, we discuss a set of techniques that can be successfully applied to solve unresearched questions in BNI studies.
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Affiliation(s)
- Pierfrancesco Nardi
- Consiglio per la ricerca e l'analisi dell'economia agraria - Research Centre for Agriculture and Environment (CREA-AA), Via della Navicella 2-4, Rome 00184, Italy
| | - Hendrikus J Laanbroek
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands; Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Graeme W Nicol
- Laboratoire Ampère, École Centrale de Lyon, Université de Lyon, Ecully, 69134, France
| | - Giancarlo Renella
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Viale dell'Università 16, 35020 Legnaro, Italy
| | - Massimiliano Cardinale
- Department of Biological and Environmental Sciences and Technologies - DiSTeBA, University of Salento, Centro Ecotekne - via Provinciale Lecce-Monteroni, I-73100, Lecce, Italy
| | - Giacomo Pietramellara
- Department of Agriculture, Food, Environment and Forestry, University of Firenze, P.le delle Cascine 28, Firenze 50144, Italy
| | - Wolfram Weckwerth
- Molecular Systems Biology (MOSYS), Department of Functional and Evolutionary Ecology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Vienna Metabolomics Center (VIME), University of Vienna, Althanstrasse 14, Vienna, 1090, Austria
| | - Alessandra Trinchera
- Consiglio per la ricerca e l'analisi dell'economia agraria - Research Centre for Agriculture and Environment (CREA-AA), Via della Navicella 2-4, Rome 00184, Italy
| | - Arindam Ghatak
- Molecular Systems Biology (MOSYS), Department of Functional and Evolutionary Ecology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria
| | - Paolo Nannipieri
- Department of Agriculture, Food, Environment and Forestry, University of Firenze, P.le delle Cascine 28, Firenze 50144, Italy
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Ayoub Moubareck C. Polymyxins and Bacterial Membranes: A Review of Antibacterial Activity and Mechanisms of Resistance. MEMBRANES 2020; 10:membranes10080181. [PMID: 32784516 PMCID: PMC7463838 DOI: 10.3390/membranes10080181] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 12/19/2022]
Abstract
Following their initial discovery in the 1940s, polymyxin antibiotics fell into disfavor due to their potential clinical toxicity, especially nephrotoxicity. However, the dry antibiotic development pipeline, together with the rising global prevalence of infections caused by multidrug-resistant (MDR) Gram-negative bacteria have both rejuvenated clinical interest in these polypeptide antibiotics. Parallel to the revival of their use, investigations into the mechanisms of action and resistance to polymyxins have intensified. With an initial known effect on biological membranes, research has uncovered the detailed molecular and chemical interactions that polymyxins have with Gram-negative outer membranes and lipopolysaccharide structure. In addition, genetic and epidemiological studies have revealed the basis of resistance to these agents. Nowadays, resistance to polymyxins in MDR Gram-negative pathogens is well elucidated, with chromosomal as well as plasmid-encoded, transferrable pathways. The aims of the current review are to highlight the important chemical, microbiological, and pharmacological properties of polymyxins, to discuss their mechanistic effects on bacterial membranes, and to revise the current knowledge about Gram-negative acquired resistance to these agents. Finally, recent research, directed towards new perspectives for improving these old agents utilized in the 21st century, to combat drug-resistant pathogens, is summarized.
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13
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Molecular characterization of the outer membrane of Pseudomonas aeruginosa. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183151. [DOI: 10.1016/j.bbamem.2019.183151] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 10/28/2019] [Accepted: 12/06/2019] [Indexed: 01/07/2023]
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14
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Intermembrane transport: Glycerophospholipid homeostasis of the Gram-negative cell envelope. Proc Natl Acad Sci U S A 2019; 116:17147-17155. [PMID: 31420510 PMCID: PMC6717313 DOI: 10.1073/pnas.1902026116] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This perspective addresses recent advances in lipid transport across the Gram-negative inner and outer membranes. While we include a summary of previously existing literature regarding this topic, we focus on the maintenance of lipid asymmetry (Mla) pathway. Discovered in 2009 by the Silhavy group [J. C. Malinverni, T. J. Silhavy, Proc. Natl. Acad. Sci. U.S.A. 106, 8009–8014 (2009)], Mla has become increasingly appreciated for its role in bacterial cell envelope physiology. Through the work of many, we have gained an increasingly mechanistic understanding of the function of Mla via genetic, biochemical, and structural methods. Despite this, there is a degree of controversy surrounding the directionality in which Mla transports lipids. While the initial discovery and subsequent studies have posited that it mediated retrograde lipid transport (removing glycerophospholipids from the outer membrane and returning them to the inner membrane), others have asserted the opposite. This Perspective aims to lay out the evidence in an unbiased, yet critical, manner for Mla-mediated transport in addition to postulation of mechanisms for anterograde lipid transport from the inner to outer membranes.
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15
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Wang F, Chen S, Deng L, Chen L, Huang Y, Tian M, Li C, Zhou X. Protective Effects of Astragaloside IV against LPS-Induced Endometritis in Mice through Inhibiting Activation of the NF-κB, p38 and JNK Signaling Pathways. Molecules 2019; 24:molecules24020373. [PMID: 30669661 PMCID: PMC6360020 DOI: 10.3390/molecules24020373] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/02/2019] [Accepted: 01/18/2019] [Indexed: 01/09/2023] Open
Abstract
Endometritis, inflammation of the endometrium, is a common reproductive obstacle disease that can lead to infertility in female animals. Astragaloside IV (AS IV), one of the major and active components of the Astragalus membranaceus (Fisch.) Bunge, is known for its anti-inflammatory effects. In the present study, the effects and mechanisms of AS IV on lipopolysaccharide (LPS)-induced endometritis were investigated using a mouse model. Female mice were prepared with AS IV (0.01 mg/g) by gavage for six days before being stimulated with LPS. The results showed that the histopathological changes, levels of inflammatory cytokines (IL-1β and TNF-α), concentration of NO, and myeloperoxidase (MPO) activity in LPS-induced uteri were attenuated significantly by pretreatment with AS IV. Furthermore, LPS-induced activations of NF-κB, p38, and JNK signal pathways were suppressed by pretreatment with AS IV. In conclusion, the data provided new evidence that AS IV effectively attenuates LPS-induced endometritis through inhibition of TLR4-mediated NF-κB, p38, and JNK signaling pathways, implying that AS IV might become a promising potential anti-inflammatory agent for endometritis and other inflammatory diseases.
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Affiliation(s)
- Fengge Wang
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
| | - Shuxiong Chen
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
| | - Liang Deng
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
| | - Lu Chen
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
| | - Yuwen Huang
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
| | - Meng Tian
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
| | - Chunjin Li
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
| | - Xu Zhou
- College of Animal Sciences, Jilin University, Changchun, 5333 Xian Road, Changchun, Jilin 130062, China.
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16
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Trivedi A, Ahmad R, Sahabjada, Misra A. Effect of alkaline pH on cytotoxicity profile of neem (Azadirachta indica) ethanolic extract against human breast cancer cell line MDA-MB-231. Eur J Integr Med 2018. [DOI: 10.1016/j.eujim.2018.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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17
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Kaur H, Abreu B, Akhmetzyanov D, Lakatos-Karoly A, Soares CM, Prisner T, Glaubitz C. Unexplored Nucleotide Binding Modes for the ABC Exporter MsbA. J Am Chem Soc 2018; 140:14112-14125. [PMID: 30289253 DOI: 10.1021/jacs.8b06739] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The ATP-binding cassette (ABC) transporter MsbA is an ATP-driven lipid-A flippase. It belongs to the ABC protein superfamily whose members are characterized by conserved motifs in their nucleotide binding domains (NBDs), which are responsible for ATP hydrolysis. Recently, it was found that MsbA could catalyze a reverse adenylate kinase (rAK)-like reaction in addition to ATP hydrolysis. Both reactions are connected and mediated by the same conserved NBD domains. Here, the structural foundations underlying the nucleotide binding to MsbA were therefore explored using a concerted approach based on conventional- and DNP-enhanced solid-state NMR, pulsed-EPR, and MD simulations. MsbA reconstituted into lipid bilayers was trapped in various catalytic states corresponding to intermediates of the coupled ATPase-rAK mechanism. The analysis of nucleotide-binding dependent chemical shift changes, and the detection of through-space contacts between bound nucleotides and MsbA within these states provides evidence for an additional nucleotide-binding site in close proximity to the Q-loop and the His-Switch. By replacing Mg2+ with Mn2+ and employing pulsed EPR spectroscopy, evidence is provided that this newly found nucleotide binding site does not interfere with the coordination of the required metal ion. Molecular dynamic (MD) simulations of nucleotide and metal binding required for the coupled ATPase-rAK mechanism have been used to corroborate these experimental findings and provide additional insight into nucleotide location, orientation, and possible binding modes.
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Affiliation(s)
- Hundeep Kaur
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance , Goethe-University Frankfurt , 60438 Frankfurt , Germany
| | - Bárbara Abreu
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier , Universidade Nova de Lisboa , 2780-157 Oeiras , Portugal
| | - Dmitry Akhmetzyanov
- Institute for Physical and Theoretical Chemistry & Centre for Biomolecular Magnetic Resonance , Goethe-University Frankfurt , 60438 Frankfurt , Germany
| | - Andrea Lakatos-Karoly
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance , Goethe-University Frankfurt , 60438 Frankfurt , Germany
| | - Cláudio M Soares
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier , Universidade Nova de Lisboa , 2780-157 Oeiras , Portugal
| | - Thomas Prisner
- Institute for Physical and Theoretical Chemistry & Centre for Biomolecular Magnetic Resonance , Goethe-University Frankfurt , 60438 Frankfurt , Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance , Goethe-University Frankfurt , 60438 Frankfurt , Germany
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18
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Cell-based screen for discovering lipopolysaccharide biogenesis inhibitors. Proc Natl Acad Sci U S A 2018; 115:6834-6839. [PMID: 29735709 DOI: 10.1073/pnas.1804670115] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
New drugs are needed to treat gram-negative bacterial infections. These bacteria are protected by an outer membrane which prevents many antibiotics from reaching their cellular targets. The outer leaflet of the outer membrane contains LPS, which is responsible for creating this permeability barrier. Interfering with LPS biogenesis affects bacterial viability. We developed a cell-based screen that identifies inhibitors of LPS biosynthesis and transport by exploiting the nonessentiality of this pathway in Acinetobacter We used this screen to find an inhibitor of MsbA, an ATP-dependent flippase that translocates LPS across the inner membrane. Treatment with the inhibitor caused mislocalization of LPS to the cell interior. The discovery of an MsbA inhibitor, which is universally conserved in all gram-negative bacteria, validates MsbA as an antibacterial target. Because our cell-based screen reports on the function of the entire LPS biogenesis pathway, it could be used to identify compounds that inhibit other targets in the pathway, which can provide insights into vulnerabilities of the gram-negative cell envelope.
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19
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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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20
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Bao H, Yang B, Zhang X, Lei L, Li Z. Bacteria-templated fabrication of a charge heterogeneous polymeric interface for highly specific bacterial recognition. Chem Commun (Camb) 2017; 53:2319-2322. [DOI: 10.1039/c6cc09242j] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using bacteria-templated polymerization, a novel bacteria-imprinted polymer (BIP) was fabricated for bacterial recognition.
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Affiliation(s)
- Han Bao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education
- Zhejiang University
- Hangzhou 310027
- P. R. China
- College of Chemical and Biological Engineering
| | - Bin Yang
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Xingwang Zhang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education
- Zhejiang University
- Hangzhou 310027
- P. R. China
- College of Chemical and Biological Engineering
| | - Lecheng Lei
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education
- Zhejiang University
- Hangzhou 310027
- P. R. China
- College of Chemical and Biological Engineering
| | - Zhongjian Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education
- Zhejiang University
- Hangzhou 310027
- P. R. China
- College of Chemical and Biological Engineering
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21
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Mayne CG, Arcario MJ, Mahinthichaichan P, Baylon JL, Vermaas JV, Navidpour L, Wen PC, Thangapandian S, Tajkhorshid E. The cellular membrane as a mediator for small molecule interaction with membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1858:2290-2304. [PMID: 27163493 PMCID: PMC4983535 DOI: 10.1016/j.bbamem.2016.04.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 01/05/2023]
Abstract
The cellular membrane constitutes the first element that encounters a wide variety of molecular species to which a cell might be exposed. Hosting a large number of structurally and functionally diverse proteins associated with this key metabolic compartment, the membrane not only directly controls the traffic of various molecules in and out of the cell, it also participates in such diverse and important processes as signal transduction and chemical processing of incoming molecular species. In this article, we present a number of cases where details of interaction of small molecular species such as drugs with the membrane, which are often experimentally inaccessible, have been studied using advanced molecular simulation techniques. We have selected systems in which partitioning of the small molecule with the membrane constitutes a key step for its final biological function, often binding to and interacting with a protein associated with the membrane. These examples demonstrate that membrane partitioning is not only important for the overall distribution of drugs and other small molecules into different compartments of the body, it may also play a key role in determining the efficiency and the mode of interaction of the drug with its target protein. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Christopher G Mayne
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States.
| | - Mark J Arcario
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States; College of Medicine, University of Illinois at Urbana-Champaign, United States.
| | - Paween Mahinthichaichan
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, United States.
| | - Javier L Baylon
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States.
| | - Josh V Vermaas
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States.
| | - Latifeh Navidpour
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States.
| | - Po-Chao Wen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States.
| | - Sundarapandian Thangapandian
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, United States.
| | - Emad Tajkhorshid
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States; College of Medicine, University of Illinois at Urbana-Champaign, United States.
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22
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Umerska A, Cassisa V, Matougui N, Joly-Guillou ML, Eveillard M, Saulnier P. Antibacterial action of lipid nanocapsules containing fatty acids or monoglycerides as co-surfactants. Eur J Pharm Biopharm 2016; 108:100-110. [PMID: 27597268 DOI: 10.1016/j.ejpb.2016.09.001] [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: 06/09/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 10/21/2022]
Abstract
Lipid nanocapsules (LNCs) are a new generation of biomimetic nanocarriers obtained via a phase inversion temperature method and have an oily core of medium-chain triglycerides that is surrounded by a shelf containing a lipophilic surfactant (lecithin) and a hydrophilic surfactant macrogol 15-hydroxystearate. The aim of the present study was to produce LNCs with antibacterial activity by replacing lecithin with other lipophilic surface active compounds, namely medium-chain fatty acids and their 1-monoglycerides, which are known to have antimicrobial properties. Fatty acids and monoglycerides were found to affect the properties of LNCs, such as particle size and zeta potential. Incorporation of a co-surfactant decreased significantly particle size (p⩽0.0039). Furthermore, incorporation of either lecithin or fatty acids with at least 10 carbon atoms yielded LNCs with the zeta potential significantly more negative than that of LNCs composed solely of triglycerides and macrogol 15 hydroxystearate (p⩽0.0310). Moreover, they were capable of decreasing the phase inversion temperature. The activity of the LCNs against Gram-positive S. aureus, including a methicillin-resistant strain, increased with increases in the length of the hydrocarbon tail. Monoglyceride-LNCs were found to be more active than the corresponding fatty acids. The opposite behaviour was observed for Gram-negative bacteria, whereby only caproic acid- and caprylic acid-LNCs were found to be active against these organisms. The monoglyceride-LNCs were bactericidal, and they killed in a time-dependent manner. Fatty acid-LNCs killed in a concentration-dependent manner. A haemolysis assay was performed to obtain preliminary information on the safety of the tested LNCs. In the case of fatty acid-LNCs, the concentrations at which bacterial growth was inhibited were similar to the haemolytic concentrations. However, monoglyceride-LNCs showed antibacterial action at concentrations much lower than those at which haemolysis was observed. In conclusion, monoglyceride-LNCs are promising candidates as carriers for the encapsulation of antibacterial agents, particularly against S. aureus.
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Affiliation(s)
- Anita Umerska
- INSERM U 1066, 'Micro et Nanomédecines biomimétiques - MINT', Angers, France; Université Angers, UMR-S1066 Angers, France.
| | - Viviane Cassisa
- Equipe 7b, ATIP Avenir, ATOMyca, U892, CRCNA, CHU Angers, France
| | - Nada Matougui
- INSERM U 1066, 'Micro et Nanomédecines biomimétiques - MINT', Angers, France; Université Angers, UMR-S1066 Angers, France
| | | | | | - Patrick Saulnier
- INSERM U 1066, 'Micro et Nanomédecines biomimétiques - MINT', Angers, France; Université Angers, UMR-S1066 Angers, France
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23
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Almostafa M, Allehyane B, Egli S, Bottaro C, Fridgen TD, Banoub J. Tandem mass spectrometry determination of the putative structure of a heterogeneous mixture of Lipid As isolated from the lipopolysaccharide of the Gram-negative bacteria Aeromonas liquefaciens SJ-19a. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:1043-1058. [PMID: 27003042 DOI: 10.1002/rcm.7540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/03/2016] [Accepted: 02/12/2016] [Indexed: 06/05/2023]
Abstract
RATIONALE We report herein the electrospray ionization mass spectrometry (ESI-MS) and low-energy collision-induced dissociation tandem mass spectrometry analysis (CID-MS/MS) of a mixture of lipid As isolated from the rough lipopolysaccharide (LPS) of the mutant wild strain of the Gram-negative bacteria Aeromonas liquefaciens (SJ-19a, resistant) grown in the presence of phages. The interaction between the phages and the Gram-negative bacteria regulates host specificity and the heterogeneity of the lipid A component of the LPS. METHODS The heterogeneous mixture of lipid As was isolated by the aqueous phenol method from the LPS of the rough wild strain of Gram-negative bacteria Aeromonas liquefaciens (SJ-19a). Hydrolysis of the LPS was with 1% acetic acid, and purification was by chromatography using Sephadex G-50 and Sephadex G-15. ESI-MS and low-energy CID-MS/MS analyses were performed with a triple-quadrupole (QqQ) and a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. RESULTS Preliminary analysis of the lipid As mixture was conducted by ESI-MS in the negative ion mode and the spectrum obtained suggested that the lipid A SJ-19a was composed of a heterogeneous mixture of different lipid A molecules. CID-MS/MS experiments confirmed the identities of the various mono-phosphorylated β-D-GlcpN-(1→6)-α-D-GlcpN disaccharide entities. This lipid As mixture was asymmetrically substituted with fatty acids such as ((R)-14:0(3-OH)), (14:0(3-(R)-(O-12:0)) and (14:0(3-(R)-O-(14:0)) located on the O-3, O-3', N-2 and N-2' positions, respectively. CONCLUSIONS Low-energy collision-induced dissociation tandem mass spectrometry in-space (QqQ-MS/MS) and in-time (FTICR-MS/MS) allowed the exact determination of the fatty acid acylation positions on the H2 PO3 →4-O'-β-D-GlcpN-(1→6)-α-D-GlcpN disaccharide backbones of this heterogeneous mixture of lipid As , composed inter alia of seven different substituted lipid As , formed from the incomplete biosynthesis of their respective LPS.
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Affiliation(s)
- Mervt Almostafa
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Bashaeer Allehyane
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Stefana Egli
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Christina Bottaro
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Travis D Fridgen
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Joseph Banoub
- Chemistry Department, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
- Special Projects, Science Branch, Department of Fisheries and Oceans Canada, St. John's, Newfoundland, Canada
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24
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Mingeot-Leclercq MP, Décout JL. Bacterial lipid membranes as promising targets to fight antimicrobial resistance, molecular foundations and illustration through the renewal of aminoglycoside antibiotics and emergence of amphiphilic aminoglycosides. MEDCHEMCOMM 2016. [DOI: 10.1039/c5md00503e] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Membrane anionic lipids as attractive targets in the design of amphiphilic antibacterial drugs active against resistant bacteria: molecular foundations and examples.
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Affiliation(s)
- Marie-Paule Mingeot-Leclercq
- Louvain Drug Research Institute
- Université catholique de Louvain
- Unité de Pharmacologie Cellulaire et Moléculaire
- Brussels
- Belgium
| | - Jean-Luc Décout
- Département de Pharmacochimie Moléculaire
- Université Grenoble Alpes/CNRS
- UMR 5063
- ICMG FR 2607
- F-38041 Grenoble
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25
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Lv X, Fu K, Li W, Wang Y, Wang J, Li H, Tian W, Cao R. TIIA attenuates LPS-induced mouse endometritis by suppressing the NF-κB signaling pathway. Can J Physiol Pharmacol 2015; 93:967-71. [DOI: 10.1139/cjpp-2015-0003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Endometritis is one of the main diseases that harms the dairy cow industry. Tanshinone IIA (TIIA), a fat-soluble alkaloid isolated from Salviae miltiorrhizae, has been reported to have potent anti-inflammatory properties. However, the anti-inflammatory effects of TIIA on a mouse model of lipopolysaccharide (LPS)-induced endometritis remain to be elucidated. The purpose of the present study was to investigate the effects of TIIA on LPS-induced mouse endometritis. TIIA was intraperitoneally injected 1 h before and 12 h after perfusion of LPS into the uterus. A histological examination was then performed, and the concentrations of myeloperoxidase (MPO) and nitric oxide (NO) in the uterine tissue were determined. The levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in a homogenate of the uterus were detected by enzyme-linked immunosorbent assay. The extent of phosphorylation of IκBα and p65 was detected by Western blotting. TIIA markedly reduced the infiltration of neutrophils, suppressed MPO activity and the concentration of NO, and attenuated the expression of TNF-α and IL-1β. Furthermore, TIIA inhibited the phosphorylation of the nuclear factor-kappa B (NF-κB) p65 subunit and the degradation of its inhibitor IκBα. All the results suggest that TIIA has strong anti-inflammatory effects on LPS-induced mouse endometritis.
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Affiliation(s)
- Xiaopei Lv
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
| | - Kaiqiang Fu
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
| | - Weishi Li
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
| | - Yu Wang
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
| | - Jifang Wang
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
| | - Huatao Li
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
| | - Wenru Tian
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
| | - Rongfeng Cao
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
- Department of Clinical Veterinary Medicine, College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, People’s Republic of China
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26
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Di Lorenzo F, De Castro C, Lanzetta R, Parrilli M, Silipo A, Molinaro A. Lipopolysaccharides as Microbe-associated Molecular Patterns: A Structural Perspective. CARBOHYDRATES IN DRUG DESIGN AND DISCOVERY 2015. [DOI: 10.1039/9781849739993-00038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The lipopolysaccharide (LPS) macromolecule is the major constituent of the external leaflet of the Gram-negative outer membrane, exerting a plethora of biological activities in animals and plants. Among all, it represents a defensive barrier which helps bacteria to resist antimicrobial compounds and external stress factors and is involved in most aspects of host–bacterium interactions such as recognition, adhesion and colonization. One of the most interesting and studied LPS features is its key role in the pathogenesis of Gram-negative infections potentially causing fever or circulatory shock. On the other hand, the LPS acts as a beneficial factor for the host since it is recognized by specific receptors of the host innate immune system; this recognition activates the host defenses culminating, in most cases, in destruction of the pathogen. Most of the biological roles of the LPS are strictly related to its primary structure; thus knowledge of the structural architecture of such a macromolecule, which is different even among bacterial strains belonging to the same species, is a first step but is essential in order to understand the molecular bases of the wide variety of biological activities exerted by LPSs.
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Affiliation(s)
- Flaviana Di Lorenzo
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Cristina De Castro
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Rosa Lanzetta
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Michelangelo Parrilli
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Alba Silipo
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
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27
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Biology and Assembly of the Bacterial Envelope. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 883:41-76. [PMID: 26621461 DOI: 10.1007/978-3-319-23603-2_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
All free-living bacterial cells are delimited and protected by an envelope of high complexity. This physiological barrier is essential for bacterial survival and assures multiple functions. The molecular assembly of the different envelope components into a functional structure represents a tremendous biological challenge and is of high interest for fundamental sciences. The study of bacterial envelope assembly has also been fostered by the need for novel classes of antibacterial agents to fight the problematic of bacterial resistance to antibiotics. This chapter focuses on the two most intensively studied classes of bacterial envelopes that belong to the phyla Firmicutes and Proteobacteria. The envelope of Firmicutes typically has one membrane and is defined as being monoderm whereas the envelope of Proteobacteria contains two distinct membranes and is referred to as being diderm. In this chapter, we will first discuss the multiple roles of the bacterial envelope and clarify the nomenclature used to describe the different types of envelopes. We will then define the architecture and composition of the envelopes of Firmicutes and Proteobacteria while outlining their similarities and differences. We will further cover the extensive progress made in the field of bacterial envelope assembly over the last decades, using Bacillus subtilis and Escherichia coli as model systems for the study of the monoderm and diderm bacterial envelopes, respectively. We will detail our current understanding of how molecular machines assure the secretion, insertion and folding of the envelope proteins as well as the assembly of the glycosidic components of the envelope. Finally, we will highlight the topics that are still under investigation, and that will surely lead to important discoveries in the near future.
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28
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Koßmehl S, Wöhlbrand L, Drüppel K, Feenders C, Blasius B, Rabus R. Subcellular protein localization (cell envelope) in Phaeobacter inhibens DSM 17395. Proteomics 2014; 13:2743-60. [PMID: 23907795 DOI: 10.1002/pmic.201300112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 04/26/2013] [Accepted: 04/30/2013] [Indexed: 11/11/2022]
Abstract
Phaeobacter inhibens DSM 17395 is a metabolically versatile, secondary metabolite producing and surface colonizing member of the alphaproteobacterial Roseobacter clade. Proteins compartmentalized across the Gram-negative cell envelope are expected to be relevant for the habitat success of P. inhibens DSM 17395. Subcellular fractionation was followed by gel- or nano-LC-based separation of proteins and peptides, respectively. Subsequent MS-based identification of in total 1187 proteins allowed allocation to cytoplasm (303 proteins), cytoplasmic membrane (346), periplasm (325), outer membrane (76), and extracellular milieu (22). Multidimensional scaling was used to visualize the spreading of heuristically allocated proteins across the five different compartments. Experimentally inferred subcellular protein localization was compared with PSORTb prediction of protein secretion and membrane localization. Determined subcellular localizations of identified proteins were interpreted to reconstruct the functional traits of the different cell envelope compartments, in particular protein secretion and sorting, direct effector molecule transit, and cell envelope biogenesis. From a proteogenomic perspective, functional prediction of 74 genes (including 17 coding for proteins of hitherto unknown function) could be refined.
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Affiliation(s)
- Sebastian Koßmehl
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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29
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Folding mechanisms of periplasmic proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1517-28. [PMID: 24239929 DOI: 10.1016/j.bbamcr.2013.10.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/11/2013] [Accepted: 10/16/2013] [Indexed: 01/03/2023]
Abstract
More than one fifth of the proteins encoded by the genome of Escherichia coli are destined to the bacterial cell envelope. Over the past 20years, the mechanisms by which envelope proteins reach their three-dimensional structure have been intensively studied, leading to the discovery of an intricate network of periplasmic folding helpers whose members have distinct but complementary roles. For instance, the correct assembly of ß-barrel proteins containing disulfide bonds depends both on chaperones like SurA and Skp for transport across the periplasm and on protein folding catalysts like DsbA and DsbC for disulfide bond formation. In this review, we provide an overview of the current knowledge about the complex network of protein folding helpers present in the periplasm of E. coli and highlight the questions that remain unsolved. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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30
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Abstract
The value of added feed enzymes (FE) in promoting growth and efficiency of nutrient utilisation is well recognised in single-stomached animal production. However, the effects of FE on the microbiome of the gastrointestinal tract (GIT) are largely unrecognised. A critical role in host nutrition, health, performance and quality of the products produced is played by the intestinal microbiota. FE can make an impact on GIT microbial ecology by reducing undigested substrates and anti-nutritive factors and producing oligosaccharides in situ from dietary NSP with potential prebiotic effects. Investigations with molecular microbiology techniques have demonstrated FE-mediated responses on energy utilisation in broiler chickens that were associated with certain clusters of GIT bacteria. Furthermore, investigations using specific enteric pathogen challenge models have demonstrated the efficacy of FE in modulating gut health. Because FE probably change the substrate characteristics along the GIT, subsequent microbiota responses will vary according to the populations present at the time of administration and their reaction to such changes. Therefore, the microbiota responses to FE administration, rather than being absolute, are a continuum or a population of responses. However, recognition that FE can make an impact on the gut microbiota and thus gut health will probably stimulate development of FE capable of modulating gut microbiota to the benefit of host health under specific production conditions. The present review brings to light opportunities and challenges for the role of major FE (carbohydrases and phytase) on the gut health of poultry and swine species with a specific focus on the impact on GIT microbiota.
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31
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Hale MR, Hill P, Lahiri S, Miller MD, Ross P, Alm R, Gao N, Kutschke A, Johnstone M, Prince B, Thresher J, Yang W. Exploring the UDP pocket of LpxC through amino acid analogs. Bioorg Med Chem Lett 2013; 23:2362-7. [PMID: 23499237 DOI: 10.1016/j.bmcl.2013.02.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/06/2013] [Accepted: 02/12/2013] [Indexed: 11/19/2022]
Abstract
Lipopolysaccharide (LPS) biosynthesis is an attractive antibacterial target as it is both conserved and essential for the survival of key pathogenic bacteria. Lipid A is the hydrophobic anchor for LPS and a key structural component of the outer membrane of Gram-negative bacteria. Lipid A biosynthesis is performed in part by a unique zinc dependent metalloamidase, LpxC (UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase), which catalyzes the first non-reversible step in lipid A biosynthesis. The UDP portion of the LpxC substrate-binding pocket has been relatively unexplored. We have designed and evaluated a series of hydroxamate based inhibitors which explore the SAR of substitutions directed into the UDP pocket with a range of substituted α-amino acid based linkers. We also provide the first wild type structure of Pseudomonas aeruginosa LpxC which was utilized in the design of many of these analogs.
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Affiliation(s)
- Michael R Hale
- Infection Innovative Medicines Unit, AstraZeneca R&D Boston, 35 Gatehouse Drive, Waltham, MA 02451, USA.
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32
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Martínez E, Estupiñán M, Pastor FJ, Busquets M, Díaz P, Manresa A. Functional characterization of ExFadLO, an outer membrane protein required for exporting oxygenated long-chain fatty acids in Pseudomonas aeruginosa. Biochimie 2013; 95:290-8. [DOI: 10.1016/j.biochi.2012.09.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 09/23/2012] [Indexed: 01/29/2023]
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33
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Pérez-Cobas AE, Artacho A, Knecht H, Ferrús ML, Friedrichs A, Ott SJ, Moya A, Latorre A, Gosalbes MJ. Differential effects of antibiotic therapy on the structure and function of human gut microbiota. PLoS One 2013; 8:e80201. [PMID: 24282523 PMCID: PMC3839934 DOI: 10.1371/journal.pone.0080201] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/28/2013] [Indexed: 02/07/2023] Open
Abstract
The human intestinal microbiota performs many essential functions for the host. Antimicrobial agents, such as antibiotics (AB), are also known to disturb microbial community equilibrium, thereby having an impact on human physiology. While an increasing number of studies investigate the effects of AB usage on changes in human gut microbiota biodiversity, its functional effects are still poorly understood. We performed a follow-up study to explore the effect of ABs with different modes of action on human gut microbiota composition and function. Four individuals were treated with different antibiotics and samples were taken before, during and after the AB course for all of them. Changes in the total and in the active (growing) microbiota as well as the functional changes were addressed by 16S rRNA gene and metagenomic 454-based pyrosequencing approaches. We have found that the class of antibiotic, particularly its antimicrobial effect and mode of action, played an important role in modulating the gut microbiota composition and function. Furthermore, analysis of the resistome suggested that oscillatory dynamics are not only due to antibiotic-target resistance, but also to fluctuations in the surviving bacterial community. Our results indicated that the effect of AB on the human gut microbiota relates to the interaction of several factors, principally the properties of the antimicrobial agent, and the structure, functions and resistance genes of the microbial community.
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Affiliation(s)
- Ana Elena Pérez-Cobas
- Unidad Mixta de Investigación en Genómica y Salud del Centro Superior de Investigación en Salud Pública e Instituto Cavanilles de Biodiversidad y Biología Evolutiva de la Universitat de València, Valencia, Spain
- CIBER en Epidemiología y Salud Pública, Madrid, Spain
| | - Alejandro Artacho
- Unidad Mixta de Investigación en Genómica y Salud del Centro Superior de Investigación en Salud Pública e Instituto Cavanilles de Biodiversidad y Biología Evolutiva de la Universitat de València, Valencia, Spain
| | - Henrik Knecht
- Institute for Clinical Molecular Biology at the Christian-Albrechts University, Kiel, Germany
| | - María Loreto Ferrús
- Unidad Mixta de Investigación en Genómica y Salud del Centro Superior de Investigación en Salud Pública e Instituto Cavanilles de Biodiversidad y Biología Evolutiva de la Universitat de València, Valencia, Spain
| | - Anette Friedrichs
- Institute for Clinical Molecular Biology at the Christian-Albrechts University, Kiel, Germany
- Department for Internal Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Stephan J. Ott
- Institute for Clinical Molecular Biology at the Christian-Albrechts University, Kiel, Germany
- Department for Internal Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Andrés Moya
- Unidad Mixta de Investigación en Genómica y Salud del Centro Superior de Investigación en Salud Pública e Instituto Cavanilles de Biodiversidad y Biología Evolutiva de la Universitat de València, Valencia, Spain
- CIBER en Epidemiología y Salud Pública, Madrid, Spain
| | - Amparo Latorre
- Unidad Mixta de Investigación en Genómica y Salud del Centro Superior de Investigación en Salud Pública e Instituto Cavanilles de Biodiversidad y Biología Evolutiva de la Universitat de València, Valencia, Spain
- CIBER en Epidemiología y Salud Pública, Madrid, Spain
- * E-mail: (MJG); (AL)
| | - María José Gosalbes
- Unidad Mixta de Investigación en Genómica y Salud del Centro Superior de Investigación en Salud Pública e Instituto Cavanilles de Biodiversidad y Biología Evolutiva de la Universitat de València, Valencia, Spain
- CIBER en Epidemiología y Salud Pública, Madrid, Spain
- * E-mail: (MJG); (AL)
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Freinkman E, Okuda S, Ruiz N, Kahne D. Regulated assembly of the transenvelope protein complex required for lipopolysaccharide export. Biochemistry 2012; 51:4800-6. [PMID: 22668317 DOI: 10.1021/bi300592c] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gram-negative bacteria are impervious to many drugs and environmental stresses because they possess an outer membrane (OM) containing lipopolysaccharide (LPS). LPS is biosynthesized at the cytoplasmic (inner) membrane and is transported to the OM by an unknown mechanism involving the LPS transport proteins, LptA-G. These proteins have been proposed to form a bridge between the two membranes; however, it is not known how this bridge is assembled to prevent mistargeting of LPS. We use in vivo photo-cross-linking to reveal the specific protein-protein interaction sites that give rise to the Lpt bridge. We also show that the formation of this transenvelope bridge cannot proceed before the correct assembly of the LPS translocon in the OM. This ordered sequence of events may ensure that LPS is never transported to the OM if it cannot be translocated across it to the cell surface.
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Affiliation(s)
- Elizaveta Freinkman
- Chemical Biology Graduate Program, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
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35
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Abstract
A glass slide covered with bacteria is pressed into another glass slide coated with partially cured polydimethylsiloxane (PDMS). The PDMS is hardened and the cells are removed to create a textured surface whose indentations preferentially capture the same type of bacteria when a mixture of bacteria is flowed over it. Overcoating the cell-imprinted PDMS with methylsilane groups causes the resulting surface to lose much of its ability to preferentially capture the imprinted bacteria, although the shapes of the imprints, measured by atomic force field microscopy, are shown to be hardly affected. We interpret this behavior as strong evidence that chemical recognition plays a dominant role in cell sorting with cell-imprinted PDMS polymer films.
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Affiliation(s)
- Kangning Ren
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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36
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Boughner LA, Doerrler WT. Multiple deletions reveal the essentiality of the DedA membrane protein family in Escherichia coli. Microbiology (Reading) 2012; 158:1162-1171. [DOI: 10.1099/mic.0.056325-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Lisa A. Boughner
- Department of Biological Sciences, Louisiana State University (LSU), Baton Rouge, LA 70803, USA
| | - William T. Doerrler
- Department of Biological Sciences, Louisiana State University (LSU), Baton Rouge, LA 70803, USA
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37
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Liechti G, Goldberg JB. Outer membrane biogenesis in Escherichia coli, Neisseria meningitidis, and Helicobacter pylori: paradigm deviations in H. pylori. Front Cell Infect Microbiol 2012; 2:29. [PMID: 22919621 PMCID: PMC3417575 DOI: 10.3389/fcimb.2012.00029] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/28/2012] [Indexed: 12/16/2022] Open
Abstract
The bacterial pathogen Helicobacter pylori is capable of colonizing the gastric mucosa of the human stomach using a variety of factors associated with or secreted from its outer membrane (OM). Lipopolysaccharide (LPS) and numerous OM proteins have been shown to be involved in adhesion and immune stimulation/evasion. Many of these factors are essential for colonization and/or pathogenesis in a variety of animal models. Despite this wide array of potential targets present on the bacterial surface, the ability of H. pylori to vary its OM profile limits the effectiveness of vaccines or therapeutics that target any single one of these components. However, it has become evident that the proteins comprising the complexes that transport the majority of these molecules to the OM are highly conserved and often essential. The field of membrane biogenesis has progressed remarkably in the last few years, and the possibility now exists for targeting the mechanisms by which β-barrel proteins, lipoproteins, and LPS are transported to the OM, resulting in loss of bacterial fitness and significant altering of membrane permeability. In this review, the OM transport machinery for LPS, lipoproteins, and outer membrane proteins (OMPs) are discussed. While the principal investigations of these transport mechanisms have been conducted in Escherichia coli and Neisseria meningitidis, here these systems will be presented in the genetic context of ε proteobacteria. Bioinformatic analysis reveals that minimalist genomes, such as that of Helicobacter pylori, offer insight into the smallest number of components required for these essential pathways to function. Interestingly, in the majority of ε proteobacteria, while the inner and OM associated apparatus of LPS, lipoprotein, and OMP transport pathways appear to all be intact, most of the components associated with the periplasmic compartment are either missing or are almost unrecognizable when compared to their E. coli counterparts. Eventual targeting of these pathways would have the net effect of severely limiting the delivery/transport of components to the OM and preventing the bacterium's ability to infect its human host.
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Affiliation(s)
- George Liechti
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Health System, Charlottesville VA, USA
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Bhardwaj A, Molineux IJ, Casjens SR, Cingolani G. Atomic structure of bacteriophage Sf6 tail needle knob. J Biol Chem 2011; 286:30867-30877. [PMID: 21705802 PMCID: PMC3162447 DOI: 10.1074/jbc.m111.260877] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/22/2011] [Indexed: 11/06/2022] Open
Abstract
Podoviridae are double-stranded DNA bacteriophages that use short, non-contractile tails to adsorb to the host cell surface. Within the tail apparatus of P22-like phages, a dedicated fiber known as the "tail needle" likely functions as a cell envelope-penetrating device to promote ejection of viral DNA inside the host. In Sf6, a P22-like phage that infects Shigella flexneri, the tail needle presents a C-terminal globular knob. This knob, absent in phage P22 but shared in other members of the P22-like genus, represents the outermost exposed tip of the virion that contacts the host cell surface. Here, we report a crystal structure of the Sf6 tail needle knob determined at 1.0 Å resolution. The structure reveals a trimeric globular domain of the TNF fold structurally superimposable with that of the tail-less phage PRD1 spike protein P5 and the adenovirus knob, domains that in both viruses function in receptor binding. However, P22-like phages are not known to utilize a protein receptor and are thought to directly penetrate the host surface. At 1.0 Å resolution, we identified three equivalents of l-glutamic acid (l-Glu) bound to each subunit interface. Although intimately bound to the protein, l-Glu does not increase the structural stability of the trimer nor it affects its ability to self-trimerize in vitro. In analogy to P22 gp26, we suggest the tail needle of phage Sf6 is ejected through the bacterial cell envelope during infection and its C-terminal knob is threaded through peptidoglycan pores formed by glycan strands.
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Affiliation(s)
- Anshul Bhardwaj
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Ian J Molineux
- Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, Texas 78712
| | - Sherwood R Casjens
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
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Bos MP, Tommassen J. The LptD chaperone LptE is not directly involved in lipopolysaccharide transport in Neisseria meningitidis. J Biol Chem 2011; 286:28688-28696. [PMID: 21705335 DOI: 10.1074/jbc.m111.239673] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The biosynthesis of lipopolysaccharide (LPS) in gram-negative bacteria is well understood, in contrast to the transport to its destination, the outer leaflet of the outer membrane. In Escherichia coli, synthesis and transport of LPS are essential processes. Neisseria meningitidis, conversely, can survive without LPS and tolerates inactivation of genes involved in LPS synthesis and transport. Here, we analyzed whether the LptA, LptB, LptC, LptE, LptF, and LptG proteins, recently implicated in LPS transport in E. coli, function similarly in N. meningitidis. None of the analyzed proteins was essential in N. meningitidis, consistent with their expected roles in LPS transport and additionally demonstrating that they are not required for an essential process such as phospholipid transport. As expected, the absence of most of the Lpt proteins resulted in a severe defect in LPS transport. However, the absence of LptE did not disturb transport of LPS to the cell surface. LptE was found to be associated with LptD, and its absence affected total levels of LptD, suggesting a chaperone-like role for LptE in LptD biogenesis. The absence of a direct role of LptE in LPS transport was substantiated by bioinformatic analyses showing a low conservation of LptE in LPS-producing bacteria. Apparently, the role of LptE in N. meningitidis deviates from that in E. coli, suggesting that the Lpt system does not function in a completely conserved manner in all gram-negative bacteria.
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Affiliation(s)
- Martine P Bos
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
| | - Jan Tommassen
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands
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Yang FL, Yang YL, Wu SH. Structure and function of glycolipids in thermophilic bacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 705:367-80. [PMID: 21618118 DOI: 10.1007/978-1-4419-7877-6_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Feng-Ling Yang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.
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Bowyer A, Baardsnes J, Ajamian E, Zhang L, Cygler M. Characterization of interactions between LPS transport proteins of the Lpt system. Biochem Biophys Res Commun 2011; 404:1093-8. [DOI: 10.1016/j.bbrc.2010.12.121] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 12/24/2010] [Indexed: 10/18/2022]
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42
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Abstract
Endotoxin refers lipopolysaccharide that constitutes the outer leaflet of the outer membrane of most Gram-negative bacteria. Lipopolysaccharide is comprised of a hydrophilic polysaccharide and a hydrophobic component known as lipid A which is responsible for the major bioactivity of endotoxin. Lipopolysaccharide can be recognized by immune cells as a pathogen-associated molecule through Toll-like receptor 4. Most enzymes and genes related to the biosynthesis and export of lipopolysaccharide have been identified in Escherichia coli, and they are shared by most Gram-negative bacteria based on available genetic information. However, the detailed structure of lipopolysaccharide differs from one bacterium to another, suggesting that additional enzymes that can modify the basic structure of lipopolysaccharide exist in bacteria, especially some pathogens. These structural modifications of lipopolysaccharide are sometimes tightly regulated. They are not required for survival but closely related to the virulence of bacteria. In this chapter we will focus on the mechanism of biosynthesis and export of lipopolysaccharide in bacteria.
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Affiliation(s)
- Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, USA
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44
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Contribution of proteomics toward solving the fascinating mysteries of the biogenesis of the envelope of Escherichia coli. Proteomics 2009; 10:771-84. [DOI: 10.1002/pmic.200900461] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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45
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Abstract
The biosynthesis of glycoconjugates such as N-glycoproteins and GPI-anchored proteins in eukaryotes and cell wall peptidoglycan and lipopolysaccharide in bacteria requires lipid intermediates to be flipped rapidly across the endoplasmic reticulum or bacterial cytoplasmic membrane (so-called biogenic membranes). Rapid flipping is also required to normalize the number of glycerophospholipids in the two leaflets of the bilayer as the membrane expands in a growing cell. Although lipids diffuse rapidly in the plane of the membrane, the intrinsic rate at which they flip across membranes is very low. Biogenic membranes possess dedicated lipid transporters or flippases to increase flipping to a physiologically sufficient rate. The flippases are "ATP-independent" and facilitate "downhill" transport. Most predicted biogenic membrane flippases have not been identified at the molecular level, and the few flippases that have been identified by genetic approaches have not been biochemically validated. Here we summarize recent progress on this fundamental topic and speculate on the mechanism(s) by which biogenic membrane flippases facilitate transbilayer lipid movement.
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Affiliation(s)
- Sumana Sanyal
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065
| | - Anant K. Menon
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065
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46
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Lipopolysaccharide: Biosynthetic pathway and structure modification. Prog Lipid Res 2009; 49:97-107. [PMID: 19815028 DOI: 10.1016/j.plipres.2009.06.002] [Citation(s) in RCA: 287] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 06/16/2009] [Accepted: 06/17/2009] [Indexed: 01/13/2023]
Abstract
Lipopolysaccharide that constitutes the outer leaflet of the outer membrane of most Gram-negative bacteria is referred to as an endotoxin. It is comprised of a hydrophilic polysaccharide and a hydrophobic component referred to as lipid A. Lipid A is responsible for the major bioactivity of endotoxin, and is recognized by immune cells as a pathogen-associated molecule. Most enzymes and genes coding for proteins responsible for the biosynthesis and export of lipopolysaccharide in Escherichia coli have been identified, and they are shared by most Gram-negative bacteria based on genetic information. The detailed structure of lipopolysaccharide differs from one bacterium to another, consistent with the recent discovery of additional enzymes and gene products that can modify the basic structure of lipopolysaccharide in some bacteria, especially pathogens. These modifications are not required for survival, but are tightly regulated in the cell and closely related to the virulence of bacteria. In this review we discuss recent studies of the biosynthesis and export of lipopolysaccharide, and the relationship between the structure of lipopolysaccharide and the virulence of bacteria.
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47
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Abstract
Robust lipid traffic within and among membranes is essential for cell growth and membrane biogenesis. Many of these transport reactions occur by nonvesicular pathways, and the genetic and biochemical details of these processes are now beginning to emerge. Intramembrane lipid transport reactions utilize P-type ATPases, ABC transporters, scramblases, and Niemann-Pick type C (NPC) family proteins. The intramembrane processes regulate the establishment and elimination of membrane lipid asymmetry, the cellular influx and efflux of sterols and phospholipids, and the egress of lysosomally deposited lipids. The intermembrane lipid transport processes play important roles in membrane biogenesis, sterol sequestration, and steroid hormone formation. The roles of soluble lipid carriers and membrane-bound lipid-transporting complexes, as well as the mechanisms for regulation of their targeting and assembly, are now becoming apparent. Elucidation of the details of these systems is providing new perspectives on the regulation of lipid traffic within cells.
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Affiliation(s)
- Dennis R Voelker
- Program in Cell Biology, Department of Medicine, National Jewish Health, Denver, CO 80206, USA.
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48
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Smriti, Zou P, Mchaourab HS. Mapping daunorubicin-binding Sites in the ATP-binding cassette transporter MsbA using site-specific quenching by spin labels. J Biol Chem 2009; 284:13904-13913. [PMID: 19278995 DOI: 10.1074/jbc.m900837200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
ATP-binding cassette (ABC) transporters transduce the free energy of ATP hydrolysis to power the mechanical work of substrate translocation across cell membranes. MsbA is an ABC transporter implicated in trafficking lipid A across the inner membrane of Escherichia coli. It has sequence similarity and overlapping substrate specificity with multidrug ABC transporters that export cytotoxic molecules in humans and prokaryotes. Despite rapid advances in structure determination of ABC efflux transporters, little is known regarding the location of substrate-binding sites in the transmembrane segment and the translocation pathway across the membrane. In this study, we have mapped residues proximal to the daunorubicin (DNR)-binding site in MsbA using site-specific, ATP-dependent quenching of DNR intrinsic fluorescence by spin labels. In the nucleotide-free MsbA intermediate, DNR-binding residues cluster at the cytoplasmic end of helices 3 and 6 at a site accessible from the membrane/water interface and extending into an aqueous chamber formed at the interface between the two transmembrane domains. Binding of a nonhydrolyzable ATP analog inverts the transporter to an outward-facing conformation and relieves DNR quenching by spin labels suggesting DNR exclusion from proximity to the spin labels. The simplest model consistent with our data has DNR entering near an elbow helix parallel to the water/membrane interface, partitioning into the open chamber, and then translocating toward the periplasm upon ATP binding.
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Affiliation(s)
- Smriti
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232
| | - Ping Zou
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232.
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Nicolaisen K, Hahn A, Schleiff E. The cell wall in heterocyst formation byAnabaenasp. PCC 7120. J Basic Microbiol 2009; 49:5-24. [DOI: 10.1002/jobm.200800300] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Sperandeo P, Dehò G, Polissi A. The lipopolysaccharide transport system of Gram-negative bacteria. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:594-602. [PMID: 19416651 DOI: 10.1016/j.bbalip.2009.01.011] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 01/16/2009] [Accepted: 01/16/2009] [Indexed: 02/06/2023]
Abstract
The cell envelope of Gram-negative bacteria consists of two distinct membranes, the inner (IM) and the outer membrane (OM) separated by the periplasm. The OM contains in the outer leaflet the lipopolysaccharide (LPS), a complex lipid with important biological activities. In the host it elicits the innate immune response whereas in the bacterium it is responsible for the peculiar permeability barrier properties exhibited by the OM. The chemical structure of LPS and its biosynthetic pathways have been fully elucidated. By contrast only recently details of the transport and assembly of LPS into the OM have emerged. LPS is synthesized in the cytoplasm and at the inner leaflet of the IM and needs to cross two different compartments, the IM and the periplasm, to reach its final destination at the OM. This review focuses on recent studies that led to our present understanding of the protein machine implicated in LPS transport and in assembly at the cell surface.
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Affiliation(s)
- Paola Sperandeo
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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