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Gangakhedkar R, Jain V. Elucidating the molecular properties and anti-mycobacterial activity of cysteine peptidase domain of D29 mycobacteriophage endolysin. J Virol 2024:e0132824. [PMID: 39287392 DOI: 10.1128/jvi.01328-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2024] [Accepted: 08/20/2024] [Indexed: 09/19/2024] Open
Abstract
Emergence of antibiotic resistance in pathogenic Mycobacterium tuberculosis (Mtb) has elevated tuberculosis to a serious global threat, necessitating alternate solutions for its eradication. D29 mycobacteriophage can infect and kill several mycobacterial species including Mtb. It encodes an endolysin LysA to hydrolyze host bacteria peptidoglycan for progeny release. We previously showed that out of the two catalytically active domains of LysA [N-terminal domain (NTD) and lysozyme-like domain], NTD, when ectopically expressed in Mycobacterium smegmatis (Msm), is able to kill the bacterium nearly as efficiently as full-length LysA. Here, we dissected the functioning of NTD to develop it as a phage-derived small molecule anti-mycobacterial therapeutic. We performed a large-scale site-directed mutagenesis of the conserved residues in NTD and examined its structure, stability, and function using molecular dynamic simulations coupled with biophysical and biochemical experiments. Our data show that NTD functions as a putative cysteine peptidase with a catalytic triad composed of Cys41, His112, and Glu137, acting as nucleophile, base, and acid, respectively, and showing characteristics similar to the NlpC/P60 family of cysteine peptidases. Additionally, our peptidoglycan hydrolysis assays suggested that NTD hydrolyzes only mycobacterial peptidoglycan and does not act on Gram-positive and Gram-negative bacterial peptidoglycans. More importantly, the combined activity of exogenously added NTD and sub-lethal doses of anti-mycobacterial drugs kills Msm in vitro and exhibits disruption of pre-formed mycobacterial biofilm. We additionally show that NTD treatment increases the permeability of antibiotics in Msm, which reduces the minimum inhibitory concentration of the antibiotics. Collectively, we present NTD as a promising phage-derived therapeutic against mycobacteria.IMPORTANCEMycobacteriophages are the viruses that use mycobacteria as host for their progeny production and, in the process, kill them. Mycobacteriophages are, therefore, considered as promising alternatives to antibiotics for killing pathogenic Mycobacterium tuberculosis. The endolysin LysA produced by mycobacteriophage D29 plays an important role in host cell lysis and virion release. Our work presented here highlights the functioning of LysA's N-terminal catalytic domain (NTD) in order to develop it as phage-derived small molecule therapeutics. We show that combined treatment of exogenously added NTD and sub-lethal doses of anti-mycobacterial drugs kills M. smegmatis, shows synergism by reducing the minimum inhibitory concentration of these antibiotics, and exhibits disruption of pre-formed mature biofilm. These outcomes and our detailed biochemical and biophysical dissection of the protein further pave the way toward engineering and development of NTD as a promising therapeutic against mycobacterial infections such as tuberculosis.
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Affiliation(s)
- Rutuja Gangakhedkar
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Vikas Jain
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
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2
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Savanagouder M, Mukku RP, Kiran U, Yeruva CV, Nagarajan N, Sharma Y, Raghunand TR. Dissecting the Ca 2+ dependence of DesA1 function in Mycobacterium tuberculosis. FEBS Lett 2024; 598:1620-1632. [PMID: 38697952 DOI: 10.1002/1873-3468.14896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 11/04/2023] [Accepted: 02/28/2024] [Indexed: 05/05/2024]
Abstract
Mycobacterium tuberculosis (M. tb) has a complex cell wall, composed largely of mycolic acids, that are crucial to its structural maintenance. The M. tb desaturase A1 (DesA1) is an essential Ca2+-binding protein that catalyses a key step in mycolic acid biosynthesis. To investigate the structural and functional significance of Ca2+ binding, we introduced mutations at key residues in its Ca2+-binding βγ-crystallin motif to generate DesA1F303A, E304Q, and F303A-E304Q. Complementation of a conditional ΔdesA1 strain of Mycobacterium smegmatis, with the Ca2+ non-binders F303A or F303A-E304Q, failed to rescue its growth phenotype; these complements also exhibited enhanced cell wall permeability. Our findings highlight the criticality of Ca2+ in DesA1 function, and its implicit role in the maintenance of mycobacterial cellular integrity.
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Affiliation(s)
| | | | - Uday Kiran
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | | | | | - Yogendra Sharma
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Tirumalai R Raghunand
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
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Aguilera-Correa JJ, Boudehen YM, Kremer L. Characterization of Mycobacterium abscessus colony-biofilms based on bi-dimensional images. Antimicrob Agents Chemother 2023; 67:e0040223. [PMID: 37565746 PMCID: PMC10508158 DOI: 10.1128/aac.00402-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/30/2023] [Indexed: 08/12/2023] Open
Abstract
Mycobacterium abscessus biofilm aggregates have been shown in the lungs of cystic fibrosis patients and are often tolerant to drugs. Herein, we analyzed bi-dimensional images of either fluorescent or Congo red-stained M. abscessus colony-biofilms grown on a membrane to monitor growth and shape of M. abscessus smooth and rough variants. These colony-biofilms responded differently to rifabutin and bedaquiline, thus highlighting the importance of the morphotype to properly address antibiotic treatment in patients with biofilm-related infections.
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Affiliation(s)
- John Jairo Aguilera-Correa
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - Yves-Marie Boudehen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
- INSERM, IRIM, Montpellier, France
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4
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Palčeková Z, Obregón-Henao A, De K, Walz A, Lam H, Philp J, Angala SK, Patterson J, Pearce C, Zuberogoitia S, Avanzi C, Nigou J, McNeil M, Muñoz Gutiérrez JF, Gilleron M, Wheat WH, Gonzalez-Juarrero M, Jackson M. Role of succinyl substituents in the mannose-capping of lipoarabinomannan and control of inflammation in Mycobacterium tuberculosis infection. PLoS Pathog 2023; 19:e1011636. [PMID: 37669276 PMCID: PMC10503756 DOI: 10.1371/journal.ppat.1011636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 09/15/2023] [Accepted: 08/25/2023] [Indexed: 09/07/2023] Open
Abstract
The covalent modification of bacterial (lipo)polysaccharides with discrete substituents may impact their biosynthesis, export and/or biological activity. Whether mycobacteria use a similar strategy to control the biogenesis of its cell envelope polysaccharides and modulate their interaction with the host during infection is unknown despite the report of a number of tailoring substituents modifying the structure of these glycans. Here, we show that discrete succinyl substituents strategically positioned on Mycobacterium tuberculosis (Mtb) lipoarabinomannan govern the mannose-capping of this lipoglycan and, thus, much of the biological activity of the entire molecule. We further show that the absence of succinyl substituents on the two main cell envelope glycans of Mtb, arabinogalactan and lipoarabinomannan, leads to a significant increase of pro-inflammatory cytokines and chemokines in infected murine and human macrophages. Collectively, our results validate polysaccharide succinylation as a critical mechanism by which Mtb controls inflammation.
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Affiliation(s)
- Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Andrés Obregón-Henao
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Kavita De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Amanda Walz
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ha Lam
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jamie Philp
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Johnathan Patterson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Camron Pearce
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Sophie Zuberogoitia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Charlotte Avanzi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Michael McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Juan F. Muñoz Gutiérrez
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - William H. Wheat
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
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Anand PK, Kaur J. Rv3539 (PPE63) of Mycobacterium Tuberculosis Promotes Survival of Mycobacterium Smegmatis in Human Macrophages Cell Line via Cell Wall Modulation of Bacteria and Altering Host's Immune Response. Curr Microbiol 2023; 80:267. [PMID: 37401981 DOI: 10.1007/s00284-023-03360-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/31/2023] [Indexed: 07/05/2023]
Abstract
The modulation of host's immune response plays an important role in the intracellular survival of Mycobacterium tuberculosis. The intracellular pathogen counteracts environmental stresses with help of the expression of several genes. The M. tuberculosis genome encodes several immune-modulatory proteins including PE (proline-glutamic acid)/PPE (proline-proline-glutamic acid) superfamily proteins. It is unclear how the unique PE/PPE proteins superfamily contributes to survival under different stress and pathophysiology conditions. Previously, we showed that PPE63 (Rv3539) has C-terminal esterase extension and was localized as a membrane attached and in extracellular compartment. Therefore, the probability of these proteins interacting with the host to modulate the host immune response cannot be ruled out. The physiological role of PPE63 was characterized by expressing the PPE63 in the M. smegmatis, a non-pathogenic strain intrinsically deficient of PPE63. The recombinant M. smegmatis expressing PPE63 altered the colony morphology, lipid composition, and integrity of the cell wall. It provided resistance to multiple hostile environmental stress conditions and several antibiotics. MS_Rv3539 demonstrated higher infection and intracellular survival in comparison to the MS_Vec in the PMA-differentiated THP-1 cells. The decreased intracellular level of ROS, NO, and expression of iNOS was observed in THP-1 cells upon infection with MS_Rv3539 in comparison to MS_Vec. Further, the decrease in expression of pro-inflammatory cytokines like IL-6, TNF-α, and IL-1β and enhanced anti-inflammatory cytokines like IL-10, pointed toward its role in immune modulation. Overall this study suggested the role of Rv3539 in enhanced intracellular survival of M. smegmatis via cell wall modulation and altered immune response of host.
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Affiliation(s)
- Pradeep K Anand
- Department of Biotechnology, Panjab University, BMS Block-1, South Campus, Chandigarh, 160014, India
| | - Jagdeep Kaur
- Department of Biotechnology, Panjab University, BMS Block-1, South Campus, Chandigarh, 160014, India.
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Pereira MMR, de Oliveira FM, da Costa AC, Junqueira-Kipnis AP, Kipnis A. Ferritin from Mycobacterium abscessus is involved in resistance to antibiotics and oxidative stress. Appl Microbiol Biotechnol 2023; 107:2577-2595. [PMID: 36862179 DOI: 10.1007/s00253-023-12420-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/22/2023] [Accepted: 01/30/2023] [Indexed: 03/03/2023]
Abstract
Mycobacterium abscessus subsp. massiliense (Mycma) is a rapidly growing Mycobacterium belonging to the M. abscessus complex that is often associated with lung and soft tissue infection outbreaks. Mycma is resistant to many antimicrobials, including those used for treating tuberculosis. Therefore, Mycma infections are difficult to treat and may lead to high infectious complication rates. Iron is essential for bacterial growth and establishment of infection. During infection, the host reduces iron concentrations as a defense mechanism. To counteract the host-induced iron deficiency, Mycma produces siderophores to capture iron. Mycma has two ferritins (encoded by mycma_0076 and mycma_0077) modulated by different iron concentrations, which allow the survival of this pathogen during iron scarcity. In this study, we constructed knockout (Mycma 0076KO) and complemented (Mycma 0076KOc) gene strains for mycma_0076 to understand the function of 0076 ferritin. Deletion of mycma_0076 in Mycma led to the transition in colony morphology from smooth to rough, alteration of the glycopeptidolipids spectra, increased permeability of the envelope, reduction in biofilm formation, increased susceptibility to antimicrobials and hydrogen peroxide-induced oxidative stress, and decreased internalization by macrophages. This study shows that Mycma_0076 ferritin in Mycma is involved in resistance to oxidative stress and antimicrobials, and alteration of cell envelope architecture. KEY POINTS: • Deletion of the mycma_0076 gene altered colony morphology to rough; • Mycma 0076KO changed GPL profile; • Absence of Mycma_0076 ferritin results in increased susceptibility to antimicrobials and oxidative stress in Mycma. Legend: a In wild-type M. abscessus subsp. massiliense strain, iron is captured from the environment by carboxymycobactins and mycobactins (1). Iron-dependent regulator (IdeR) proteins bind to ferrous iron (Fe+2) in the bacterial cytoplasm leading to the activation of the IdeR-Fe+2 complex (2). The activated complex binds to the promoter regions of iron-dependent genes, called iron box, which in turn help in the recruitment of RNA polymerase to promote transcription of genes such as mycma_0076 and mycma_0077 ferritin genes (3). Mycma_0076 and Mycma_0077 ferritins bind to excess iron in the medium and promote Fe2+ oxidation into ferric iron (Fe3+) and store iron molecules to be released under iron scarcity conditions. (4) Genes related to biosynthesis and transport of glycopeptidolipids (GPL) are expressed normally and the cell envelope is composed of different GPL species (colored squares represented on the cell surface (GPLs). Consequently, WT Mycma present smooth colony phenotype (5). b In Mycma 0076KO strain, the lack of ferritin 0076 causes overexpression of mycma_0077 (6), but does not restore wild-type iron homeostasis and thus may result in free intracellular iron, even in the presence of miniferritins (MaDps). The excess iron potentiates oxidative stress (7) by generating hydroxyl radicals through Fenton Reaction. During this process, through an unknown mechanism, that could involve Lsr2 (8), the expression of GPL synthesis locus is regulated positively and/or negatively, resulting in alteration of GPL composition in the membrane (as represented by different colors of squares on the cell surface), resulting in a rough colony phenotype (9). The changes of GPL can increase cell wall permeability, contributing to antimicrobial susceptibility (10).
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Affiliation(s)
- Maria Micaella Rodrigues Pereira
- Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, GO, Brazil
- Tropical Medicine and Public Health Graduate Program at Federal, University of Goiás, Goiânia, GO, Brazil
| | - Fábio Muniz de Oliveira
- Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, GO, Brazil
- Tropical Medicine and Public Health Graduate Program at Federal, University of Goiás, Goiânia, GO, Brazil
- Indiana Center for Regenerative Medicine and Engineering, School of Medicine, Indiana University, Indianapolis, IN, USA
| | | | | | - André Kipnis
- Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, GO, Brazil.
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Hershko Y, Adler A, Barkan D, Meir M. Glycopeptidolipid Defects Leading to Rough Morphotypes of Mycobacterium abscessus Do Not Confer Clinical Antibiotic Resistance. Microbiol Spectr 2023; 11:e0527022. [PMID: 36722959 PMCID: PMC10101123 DOI: 10.1128/spectrum.05270-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/19/2023] [Indexed: 02/02/2023] Open
Abstract
Mycobacterium abscessus is an emerging pathogen causing severe pulmonary infections. Within chronically infected patients, M. abscessus isolates undergo molecular changes leading to increased virulence and antibiotic resistance. Specifically, mutations in glycopeptidolipid (GPL) synthesis genes, leading to the rough phenotype, are associated with invasive, nonremitting infections and a severe clinical course. It has been unclear whether GPL defects confer antibiotic resistance independently of other molecular changes. We used transposon technology to isolate a rough (GPL-defective; Tn MABS_4099cZeoR) mutant and compare it to a fully isogenic parent strain (ATCC 19977) bearing wild-type zeocin resistance (WTZeoR). Antibiotic susceptibility profiles of Tn_4099cZeoR and WTZeoR were tested and compared using the Sensititre RAPMYCOI antimicrobial susceptibility test plate. MICs were evaluated within clinically relevant values according to the Clinical and Laboratory Standards Institute (CLSI) standards. We found that M. abscessus with rough colony morphotype (Tn_4009c) had comparable antibiotic susceptibility to its smooth isogenic WT counterpart. Small differences (a 1:2 dilution) in MICs were found for imipenem, cefoxitin, and tigecycline, yet those small differences did not change the clinical susceptibility report for these antibiotics, as they fell within the same CLSI cutoffs for resistance. While small alternations in susceptibility to imipenem, cefoxitin, and tigecycline were noted, we conclude that the GPL mutations in M. abscessus did not confer clinically significant antibiotic resistance. Increased antibiotic resistance in the clinical setting may occur in an unrelated and parallel manner to GPL mutations. IMPORTANCE Mycobacterium abscessus chronically infects patients with preexisting lung diseases, leading to progressive deterioration in pulmonary function. The common perception among clinicians is that the rough phenotype is associated with progressive disease and severe clinical course, manifested as a widespread inflammatory response and resistance to antibacterials. However, as clinical isolates accumulate hundreds of mutations over the prolonged course of infection, it is unclear whether the rough phenotype per se is responsible for the antibiotic resistance seen in late-stage infections, or whether the resistance is related to other genetic changes in the bacteria. Previous studies mostly compared rough and smooth clinical isolates. Here, for the first time, we compared WT smooth bacteria to a specific rough, GPL-associated, otherwise-isogenic mutant. We determined that the rough morphotype had essentially identical antibiotic susceptibilities as the parent strain. The mechanistic basis for the antibiotic resistance observed in rough clinical isolates is therefore most probably related to other genetic determinants.
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Affiliation(s)
- Yizhak Hershko
- Clinical Microbiology Laboratory, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Koret School of Veterinary Medicine, Robert H. Smith Faculty for Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Amos Adler
- Clinical Microbiology Laboratory, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Daniel Barkan
- Koret School of Veterinary Medicine, Robert H. Smith Faculty for Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Michal Meir
- Ruth Rappaport Children's Hospital, Rambam Medical Center, Haifa, Israel
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Wani SR, Dubey AA, Jain V. Ms6244 is a novel Mycobacterium smegmatis TetR family transcriptional repressor that regulates cell growth and morphophysiology. FEBS Lett 2023; 597:1428-1440. [PMID: 36694284 DOI: 10.1002/1873-3468.14582] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/02/2023] [Accepted: 01/04/2023] [Indexed: 01/26/2023]
Abstract
Transcriptional factors such as the TetR family of transcriptional regulators (TFTRs) are widely found amongst bacteria, including mycobacteria, and are accountable for their survival. Here, we characterized a novel TFTR, Ms6244, from Mycobacterium smegmatis that negatively autoregulates its expression and represses its neighbouring gene, Ms6243. We also report the binding of Ms6244 to the inverted repeats in the intergenic region of Ms6244 and Ms6243. Further, an Ms6244-deleted strain shows various morpho-physiological differences compared to the wild type. We further confirmed that the deletion of Ms6244 itself and not the resultant Ms6243 overexpression is the cause of the altered physiology. Our data thus suggest that Ms6244 is an essential regulator, having far-reaching effects on M. smegmatis physiology.
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Affiliation(s)
- Saloni Rajesh Wani
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Abhishek Anil Dubey
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Vikas Jain
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
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9
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Ratna S, Daniel J. Stress-induced non-replicating Mycobacterium smegmatis incorporates exogenous fatty acids into glycopeptidolipids. Microb Pathog 2023; 174:105943. [PMID: 36502992 DOI: 10.1016/j.micpath.2022.105943] [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: 08/09/2022] [Revised: 11/03/2022] [Accepted: 12/08/2022] [Indexed: 12/13/2022]
Abstract
Nontuberculous mycobacteria (NTM) such as Mycobacterium smegmatis accumulate high levels of glycopeptidolipids (GPLs) on their outer surface. The biosynthesis of GPLs is critically linked to biofilm formation by NTM which also includes opportunistic pathogens such as Mycobacterium abscessus. Although GPLs have been investigated in many earlier studies, the biosynthesis of GPLs using exogenous fatty acids in M. smegmatis subjected to stresses encountered by mycobacteria during infection of the human body has not been studied. Therefore, we subjected M. smegmatis to different combinations of the three stresses of hypoxia, acidic pH and nutrient starvation and report here that the metabolic incorporation of radiolabeled long-chain fatty acids into alkali-stable GPLs was significantly increased under these stress conditions. Endogenously synthesized fatty acids were not preferred for GPL biosynthesis by M. smegmatis subjected to the triple stress combination. Our observations indicate that GPLs may play important roles in cell surface modifications associated with the non-replicating state of M. smegmatis. Our experimental model reported here would be useful in the further study of GPL biosynthesis from exogenous fatty acid sources in M. smegmatis subjected to hypoxia, nutrient starvation and acidic stress conditions and help in the screening of candidate drugs that target this biochemical pathway in pathogenic NTM.
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Affiliation(s)
- Sushanta Ratna
- Department of Biological Sciences, Purdue University Fort Wayne, Fort Wayne, IN, 46805, USA
| | - Jaiyanth Daniel
- Department of Biological Sciences, Purdue University Fort Wayne, Fort Wayne, IN, 46805, USA.
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10
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Cooper C, Peterson EJR, Bailo R, Pan M, Singh A, Moynihan P, Nakaya M, Fujiwara N, Baliga N, Bhatt A. MadR mediates acyl CoA-dependent regulation of mycolic acid desaturation in mycobacteria. Proc Natl Acad Sci U S A 2022; 119:e2111059119. [PMID: 35165190 PMCID: PMC8872791 DOI: 10.1073/pnas.2111059119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/28/2021] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium tuberculosis has a lipid-rich cell envelope that is remodeled throughout infection to enable adaptation within the host. Few transcriptional regulators have been characterized that coordinate synthesis of mycolic acids, the major cell wall lipids of mycobacteria. Here, we show that the mycolic acid desaturase regulator (MadR), a transcriptional repressor of the mycolate desaturase genes desA1 and desA2, controls mycolic acid desaturation and biosynthesis in response to cell envelope stress. A madR-null mutant of M. smegmatis exhibited traits of an impaired cell wall with an altered outer mycomembrane, accumulation of a desaturated α-mycolate, susceptibility to antimycobacterials, and cell surface disruption. Transcriptomic profiling showed that enriched lipid metabolism genes that were significantly down-regulated upon madR deletion included acyl-coenzyme A (aceyl-CoA) dehydrogenases, implicating it in the indirect control of β-oxidation pathways. Electromobility shift assays and binding affinities suggest a unique acyl-CoA pool-sensing mechanism, whereby MadR is able to bind a range of acyl-CoAs, including those with unsaturated as well as saturated acyl chains. MadR repression of desA1/desA2 is relieved upon binding of saturated acyl-CoAs of chain length C16 to C24, while no impact is observed upon binding of shorter chain and unsaturated acyl-CoAs. We propose this mechanism of regulation as distinct to other mycolic acid and fatty acid synthesis regulators and place MadR as the key regulatory checkpoint that coordinates mycolic acid remodeling during infection in response to host-derived cell surface perturbation.
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Affiliation(s)
- Charlotte Cooper
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | | | - Rebeca Bailo
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Min Pan
- Institute for Systems Biology, Seattle, WA 98109
| | - Albel Singh
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Patrick Moynihan
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | | | - Nagatoshi Fujiwara
- Department of Food and Nutrition, Faculty of Contemporary Human Life Science, Tezukayama University, Nara 631-8585, Japan
| | - Nitin Baliga
- Institute for Systems Biology, Seattle, WA 98109;
- Department of Biology, University of Washington, Seattle, WA 98105
- Department of Microbiology, University of Washington, Seattle, WA 98105
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98105
- Lawrence Berkeley National Lab, Berkeley, CA 94720
| | - Apoorva Bhatt
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK;
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
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Bendre AD, Peters PJ, Kumar J. Recent Insights into the Structure and Function of Mycobacterial Membrane Proteins Facilitated by Cryo-EM. J Membr Biol 2021; 254:321-341. [PMID: 33954837 PMCID: PMC8099146 DOI: 10.1007/s00232-021-00179-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 03/23/2021] [Indexed: 12/26/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is one of the deadliest pathogens encountered by humanity. Over the decades, its characteristic membrane organization and composition have been understood. However, there is still limited structural information and mechanistic understanding of the constituent membrane proteins critical for drug discovery pipelines. Recent advances in single-particle cryo-electron microscopy and cryo-electron tomography have provided the much-needed impetus towards structure determination of several vital Mtb membrane proteins whose structures were inaccessible via X-ray crystallography and NMR. Important insights into membrane composition and organization have been gained via a combination of electron tomography and biochemical and biophysical assays. In addition, till the time of writing this review, 75 new structures of various Mtb proteins have been reported via single-particle cryo-EM. The information obtained from these structures has improved our understanding of the mechanisms of action of these proteins and the physiological pathways they are associated with. These structures have opened avenues for structure-based drug design and vaccine discovery programs that might help achieve global-TB control. This review describes the structural features of selected membrane proteins (type VII secretion systems, Rv1819c, Arabinosyltransferase, Fatty Acid Synthase, F-type ATP synthase, respiratory supercomplex, ClpP1P2 protease, ClpB disaggregase and SAM riboswitch), their involvement in physiological pathways, and possible use as a drug target. Tuberculosis is a deadly disease caused by Mycobacterium tuberculosis. The Cryo-EM and tomography have simplified the understanding of the mycobacterial membrane organization. Some proteins are located in the plasma membrane; some span the entire envelope, while some, like MspA, are located in the mycomembrane. Cryo-EM has made the study of such membrane proteins feasible.
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Affiliation(s)
- Ameya D Bendre
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University Campus, Ganeshkhind, Pune, Maharashtra, 411007, India
| | - Peter J Peters
- The Maastricht Multimodal Molecular Imaging Institute (M4I), Division of Nanoscopy, Maastricht University, Maastricht, The Netherlands
| | - Janesh Kumar
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University Campus, Ganeshkhind, Pune, Maharashtra, 411007, India.
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Jackson M, Stevens CM, Zhang L, Zgurskaya HI, Niederweis M. Transporters Involved in the Biogenesis and Functionalization of the Mycobacterial Cell Envelope. Chem Rev 2021; 121:5124-5157. [PMID: 33170669 PMCID: PMC8107195 DOI: 10.1021/acs.chemrev.0c00869] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The biology of mycobacteria is dominated by a complex cell envelope of unique composition and structure and of exceptionally low permeability. This cell envelope is the basis of many of the pathogenic features of mycobacteria and the site of susceptibility and resistance to many antibiotics and host defense mechanisms. This review is focused on the transporters that assemble and functionalize this complex structure. It highlights both the progress and the limits of our understanding of how (lipo)polysaccharides, (glyco)lipids, and other bacterial secretion products are translocated across the different layers of the cell envelope to their final extra-cytoplasmic location. It further describes some of the unique strategies evolved by mycobacteria to import nutrients and other products through this highly impermeable barrier.
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Affiliation(s)
- Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Casey M. Stevens
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
| | - Helen I. Zgurskaya
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
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The thick waxy coat of mycobacteria, a protective layer against antibiotics and the host's immune system. Biochem J 2020; 477:1983-2006. [PMID: 32470138 PMCID: PMC7261415 DOI: 10.1042/bcj20200194] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022]
Abstract
Tuberculosis, caused by the pathogenic bacterium Mycobacterium tuberculosis (Mtb), is the leading cause of death from an infectious disease, with a mortality rate of over a million people per year. This pathogen's remarkable resilience and infectivity is largely due to its unique waxy cell envelope, 40% of which comprises complex lipids. Therefore, an understanding of the structure and function of the cell wall lipids is of huge indirect clinical significance. This review provides a synopsis of the cell envelope and the major lipids contained within, including structure, biosynthesis and roles in pathogenesis.
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14
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Structure-based drug repurposing to inhibit the DNA gyrase of Mycobacterium tuberculosis. Biochem J 2020; 477:4167-4190. [PMID: 33030198 DOI: 10.1042/bcj20200462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/02/2020] [Accepted: 10/08/2020] [Indexed: 12/11/2022]
Abstract
Drug repurposing is an alternative avenue for identifying new drugs to treat tuberculosis (TB). Despite the broad-range of anti-tubercular drugs, the emergence of multi-drug-resistant and extensively drug-resistant strains of Mycobacterium tuberculosis (Mtb) H37Rv, as well as the significant death toll globally, necessitates the development of new and effective drugs to treat TB. In this study, we have employed a drug repurposing approach to address this drug resistance problem by screening the drugbank database to identify novel inhibitors of the Mtb target enzyme, DNA gyrase. The compounds were screened against the ATPase domain of the gyrase B subunit (MtbGyrB47), and the docking results showed that echinacoside, doxorubicin, epirubicin, and idarubicin possess high binding affinities against MtbGyrB47. Comprehensive assessment using fluorescence spectroscopy, surface plasmon resonance spectroscopy (SPR), and circular dichroism (CD) titration studies revealed echinacoside as a potent binder of MtbGyrB47. Furthermore, ATPase, and DNA supercoiling assays exhibited an IC50 values of 2.1-4.7 µM for echinacoside, doxorubicin, epirubicin, and idarubicin. Among these compounds, the least MIC90 of 6.3 and 12 μM were observed for epirubicin and echinacoside, respectively, against Mtb. Our findings indicate that echinacoside and epirubicin targets mycobacterial DNA gyrase, inhibit its catalytic cycle, and retard mycobacterium growth. Further, these compounds exhibit potential scaffolds for optimizing novel anti-mycobacterial agents that can act on drug-resistant strains.
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Daher W, Leclercq LD, Viljoen A, Karam J, Dufrêne YF, Guérardel Y, Kremer L. O-Methylation of the Glycopeptidolipid Acyl Chain Defines Surface Hydrophobicity of Mycobacterium abscessus and Macrophage Invasion. ACS Infect Dis 2020; 6:2756-2770. [PMID: 32857488 DOI: 10.1021/acsinfecdis.0c00490] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mycobacterium abscessus, an emerging pathogen responsible for severe lung infections in cystic fibrosis patients, displays either smooth (S) or rough (R) morphotypes. The S-to-R transition is associated with reduced levels of glycopeptidolipid (GPL) production and is correlated with increased pathogenicity in animal and human hosts. While the structure of GPL is well established, its biosynthetic pathway is incomplete. In addition, the biological functions of the distinct structural parts of this complex lipid remain elusive. Herein, the fmt gene encoding a putative O-methyltransferase was deleted in the M. abscessus S variant. Subsequent biochemical and structural analyses demonstrated that methoxylation of the fatty acyl chain of GPL was abrogated in the Δfmt mutant, and this defect was rescued upon complementation with a functional fmt gene. In contrast, the introduction of fmt derivatives mutated at residues essential for methyltransferase activity failed to complement GPL defects, indicating that fmt encodes an O-methyltransferase. Unexpectedly, phenotypic analyses showed that Δfmt was more hydrophilic than its parental progenitor, as demonstrated by hexadecane-aqueous buffer partitioning and atomic force microscopy experiments with hydrophobic probes. Importantly, the invasion rate of THP-1 macrophages by Δfmt was reduced by 50% when compared to the wild-type strain. Together, these results indicate that Fmt O-methylates the lipid moiety of GPL and plays a substantial role in conditioning the surface hydrophobicity of M. abscessus as well as in the early steps of the interaction between the bacilli and macrophages.
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Affiliation(s)
- Wassim Daher
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
- INSERM, IRIM, 34293 Montpellier, France
| | - Louis-David Leclercq
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Albertus Viljoen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Jona Karam
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Yann Guérardel
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
- INSERM, IRIM, 34293 Montpellier, France
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Nishimura T, Shimoda M, Tamizu E, Uno S, Uwamino Y, Kashimura S, Yano I, Hasegawa N. The rough colony morphotype of Mycobacterium avium exhibits high virulence in human macrophages and mice. J Med Microbiol 2020; 69:1020-1033. [PMID: 32589124 DOI: 10.1099/jmm.0.001224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction. The incidence of Mycobacterium avium complex (MAC) pulmonary disease (MAC PD), a refractory chronic respiratory tract infection, is increasing worldwide. MAC has three predominant colony morphotypes: smooth opaque (SmO), smooth transparent (SmT) and rough (Rg).Aim. To determine whether colony morphotypes can predict the prognosis of MAC PD, we evaluated the virulence of SmO, SmT and Rg in mice and in human macrophages.Methodology. We compared the characteristics of mice and human macrophages infected with the SmO, SmT, or Rg morphotypes of M. avium subsp. hominissuis 104. C57BL/6 mice and human macrophages derived from peripheral mononuclear cells were used in these experiments.Results. In comparison to SmO- or SmT-infected mice, Rg-infected mice revealed severe pathologically confirmed pneumonia, increased lung weight and increased lung bacterial burden. Rg-infected macrophages revealed significant cytotoxicity, increased bacterial burden, secretion of proinflammatory cytokines (TNF-α and IL-6) and chemokines (CCL5 and CCL3), and formation of cell clusters. Rg formed larger bacterial aggregates than SmO and SmT. Cytotoxicity, bacterial burden and secretion of IL-6, CCL5 and CCL3 were induced strongly by Rg infection, and were decreased by disaggregation of the bacteria.Conclusion. M. avium Rg, which is associated with bacterial aggregation, has the highest virulence among the predominant colony morphotypes.
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Affiliation(s)
| | - Masayuki Shimoda
- Department of Pathology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Eiko Tamizu
- Department of Infectious Diseases, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Shunsuke Uno
- Department of Infectious Diseases, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Yoshifumi Uwamino
- Department of Laboratory Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Shoko Kashimura
- Department of Infectious Diseases, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Ikuya Yano
- Department of Bacteriology, Osaka City University Graduate School of Medicine, Osaka-city, Osaka, Japan
| | - Naoki Hasegawa
- Department of Infectious Diseases, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
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Wiersma CJ, Belardinelli JM, Avanzi C, Angala SK, Everall I, Angala B, Kendall E, de Moura VCN, Verma D, Benoit J, Brown KP, Jones V, Malcolm KC, Strong M, Nick JA, Floto RA, Parkhill J, Ordway DJ, Davidson RM, McNeil MR, Jackson M. Cell Surface Remodeling of Mycobacterium abscessus under Cystic Fibrosis Airway Growth Conditions. ACS Infect Dis 2020; 6:2143-2154. [PMID: 32551551 DOI: 10.1021/acsinfecdis.0c00214] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Understanding the physiological processes underlying the ability of Mycobacterium abscessus to become a chronic pathogen of the cystic fibrosis (CF) lung is important to the development of prophylactic and therapeutic strategies to better control and treat pulmonary infections caused by these bacteria. Gene expression profiling of a diversity of M. abscessus complex isolates points to amino acids being significant sources of carbon and energy for M. abscessus in both CF sputum and synthetic CF medium and to the bacterium undergoing an important metabolic reprogramming in order to adapt to this particular nutritional environment. Cell envelope analyses conducted on the same representative isolates further revealed unexpected structural alterations in major cell surface glycolipids known as the glycopeptidolipids (GPLs). Besides showing an increase in triglycosylated forms of these lipids, CF sputum- and synthetic CF medium-grown isolates presented as yet unknown forms of GPLs representing as much as 10% to 20% of the total GPL content of the cells, in which the classical amino alcohol located at the carboxy terminal of the peptide, alaninol, is replaced with the branched-chain amino alcohol leucinol. Importantly, both these lipid changes were exacerbated by the presence of mucin in the culture medium. Collectively, our results reveal potential new drug targets against M. abscessus in the CF airway and point to mucin as an important host signal modulating the cell surface composition of this pathogen.
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Affiliation(s)
- Crystal J. Wiersma
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Juan Manuel Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Charlotte Avanzi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Isobel Everall
- MRC-Laboratory of Molecular Biology, Molecular Immunity Unit, University of Cambridge Department of Medicine, Cambridge CB2 0QH, United Kingdom
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, United Kingdom
| | - Bhanupriya Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Edward Kendall
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Vinicius Calado Nogueira de Moura
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Deepshikha Verma
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Jeanne Benoit
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado 80206, United States
| | - Karen P. Brown
- MRC-Laboratory of Molecular Biology, Molecular Immunity Unit, University of Cambridge Department of Medicine, Cambridge CB2 0QH, United Kingdom
- Cambridge Centre for Lung Infection, Papworth Hospital, Cambridge CB2 0AY, United Kingdom
| | - Victoria Jones
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Kenneth C. Malcolm
- Department of Medicine, National Jewish Health, Denver, Colorado 80206, United Kingdom
- Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Michael Strong
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado 80206, United States
- Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Jerry A. Nick
- Department of Medicine, National Jewish Health, Denver, Colorado 80206, United Kingdom
- Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - R. Andres Floto
- MRC-Laboratory of Molecular Biology, Molecular Immunity Unit, University of Cambridge Department of Medicine, Cambridge CB2 0QH, United Kingdom
- Cambridge Centre for Lung Infection, Papworth Hospital, Cambridge CB2 0AY, United Kingdom
| | - Julian Parkhill
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, United Kingdom
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom
| | - Diane J. Ordway
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Rebecca M. Davidson
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado 80206, United States
| | - Michael R. McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
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Palčeková Z, Gilleron M, Angala SK, Belardinelli JM, McNeil M, Bermudez LE, Jackson M. Polysaccharide Succinylation Enhances the Intracellular Survival of Mycobacterium abscessus. ACS Infect Dis 2020; 6:2235-2248. [PMID: 32657565 PMCID: PMC7875180 DOI: 10.1021/acsinfecdis.0c00361] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Lipoarabinomannan (LAM) and its biosynthetic precursors, phosphatidylinositol mannosides (PIMs) and lipomannan (LM) play important roles in the interactions of Mycobacterium tuberculosis with phagocytic cells and the modulation of the host immune response, but nothing is currently known of the impact of these cell envelope glycoconjugates on the physiology and pathogenicity of nontuberculous mycobacteria. We here report on the structures of Mycobacterium abscessus PIM, LM, and LAM. Intriguingly, these structures differ from those reported previously in other mycobacterial species in several respects, including the presence of a methyl substituent on one of the mannosyl residues of PIMs as well as the PIM anchor of LM and LAM, the size and branching pattern of the mannan backbone of LM and LAM, and the modification of the arabinan domain of LAM with both succinyl and acetyl substituents. Investigations into the biological significance of some of these structural oddities point to the important role of polysaccharide succinylation on the ability of M. abscessus to enter and survive inside human macrophages and epithelial cells and validate for the first time cell envelope polysaccharides as important modulators of the virulence of this emerging pathogen.
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Affiliation(s)
- Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Shiva kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Juan Manuel Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Michael McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Luiz E. Bermudez
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
- Department of Microbiology, College of Science, Oregon State University, Corvallis, OR 97331, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
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Features of the biochemistry of Mycobacterium smegmatis, as a possible model for Mycobacterium tuberculosis. J Infect Public Health 2020; 13:1255-1264. [PMID: 32674978 DOI: 10.1016/j.jiph.2020.06.023] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/28/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
An alternate host for mycobacteria is Mycobacterium smegmatis which is used frequently. It is a directly budding eco-friendly organism not emulated as human infection. It is mainly useful for the investigation of various microorganisms in the sort of Mycobacteria in cell culture laboratories. Some Mycobacterium species groups that is normal, unsafe ailments, likely to Mycobacterium leprae, Mycobacterium tuberculosis and Mycobacterium bovis. At present, various laboratories are clean and culture this type of species to make an opinion that fascinating route of harmful Mycobacteria. This publication provides aggregate data on cell shape, genome studies, ecology, pathology and utilization of M. smegmatis.
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Samanta S, Biswas P, Banerjee A, Bose A, Siddiqui N, Nambi S, Saini DK, Visweswariah SS. A universal stress protein in Mycobacterium smegmatis sequesters the cAMP-regulated lysine acyltransferase and is essential for biofilm formation. J Biol Chem 2020; 295:1500-1516. [PMID: 31882539 PMCID: PMC7008380 DOI: 10.1074/jbc.ra119.011373] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 12/19/2019] [Indexed: 01/08/2023] Open
Abstract
Universal stress proteins (USPs) are present in many bacteria, and their expression is enhanced under various environmental stresses. We have previously identified a USP in Mycobacterium smegmatis that is a product of the msmeg_4207 gene and is a substrate for a cAMP-regulated protein lysine acyltransferase (KATms; MSMEG_5458). Here, we explored the role of this USP (USP4207) in M. smegmatis and found that its gene is present in an operon that also contains genes predicted to encode a putative tripartite tricarboxylate transporter (TTT). Transcription of the TTT-usp4207 operon was induced in the presence of citrate and tartrate, perhaps by the activity of a divergent histidine kinase-response regulator gene pair. A usp4207-deleted strain had rough colony morphology and reduced biofilm formation compared with the WT strain; however, both normal colony morphology and biofilm formation were restored in a Δusp4207Δkatms strain. We identified several proteins whose acetylation was lost in the Δkatms strain, and whose transcript levels increased in M. smegmatis biofilms along with that of USP4207, suggesting that USP4207 insulates KATms from its other substrates in the cell. We propose that USP4207 sequesters KATms from diverse substrates whose activities are down-regulated by acylation but are required for biofilm formation, thus providing a defined role for this USP in mycobacterial physiology and stress responses.
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Affiliation(s)
- Sintu Samanta
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Priyanka Biswas
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Arka Banerjee
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Avipsa Bose
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Nida Siddiqui
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Subhalaxmi Nambi
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Deepak Kumar Saini
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Sandhya S Visweswariah
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, Karnataka 560012, India.
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21
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Jakkala K, Ajitkumar P. Hypoxic Non-replicating Persistent Mycobacterium tuberculosis Develops Thickened Outer Layer That Helps in Restricting Rifampicin Entry. Front Microbiol 2019; 10:2339. [PMID: 31681204 PMCID: PMC6797554 DOI: 10.3389/fmicb.2019.02339] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 09/25/2019] [Indexed: 01/25/2023] Open
Abstract
Bacteria undergo adaptive morphological changes to survive under stress conditions. The present work documents the morphological changes in Mycobacterium tuberculosis (Mtb) cells cultured under hypoxic condition using Wayne’s in vitro hypoxia model involving non-replicating persistence stages 1 and 2 (NRP stage 1 and NRP stage 2) and reveals their physiological significance. Transmission electron microscopy of the NRP stage 2 cells showed uneven but thick outer layer (TOL), unlike the evenly thin outer layer of the actively growing mid-log phase (MLP) cells. On the contrary, the saprophytic Mycobacterium smegmatis NRP stage 2 cells lacked TOL. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) of the Mtb NRP stage 2 cells confirmed the rough uneven surface unlike the smooth surface of the MLP cells. Zeta potential measurements showed high negative charge on the surface of NRP stage 2 cells and polysaccharide specific calcofluor white (CFW) staining of the cells revealed high content of polysaccharide in the TOL. This observation was supported by the real-time PCR data showing high levels of expression of the genes involved in the synthesis of sugars, such as trehalose, mannose and others, which are implicated in polysaccharide synthesis. Experiments to understand the physiological significance of the TOL revealed restricted entry of the biologically low-active 5-carboxyfluorescein-rifampicin (5-FAM-RIF), at concentrations equivalent to microbicidal concentrations of the unconjugated biologically active rifampicin, into the NRP stage 2 cells, unlike in the MLP cells. Further, as expected, mechanical removal of the TOL by mild bead beating or release of the NRP stage 2 cells from hypoxia into normoxia in fresh growth medium also significantly increased 5-FAM-RIF permeability into the NRP stage 2 cells to an extent comparable to that into the MLP cells. Taken together, these observations revealed that Mtb cells under hypoxia develop TOL that helps in restricting rifampicin entry, thereby conferring rifampicin tolerance.
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Affiliation(s)
- Kishor Jakkala
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
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Gupta S, Kumar A, Singh K, Kumari R, Sharma A, Singh RK, Pandey SK, Anupurba S. Rv1273c, an ABC transporter of Mycobacterium tuberculosis promotes mycobacterial intracellular survival within macrophages via modulating the host cell immune response. Int J Biol Macromol 2019; 142:320-331. [PMID: 31593717 DOI: 10.1016/j.ijbiomac.2019.09.103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 08/18/2019] [Accepted: 09/13/2019] [Indexed: 02/06/2023]
Abstract
Mycobacterium proteins, especially cell wall associated proteins, interact with host macrophage to regulate the functions and cytokine production. So, identification and characterization of such proteins is essential for understanding tuberculosis pathogenesis. The role of the ABC transporter proteins in the pathophysiology and virulence of Mycobacterium tuberculosis is not clearly understood. In the present study, Rv1273c, an ABC transporter, has been expressed in a non-pathogenic and fast growing Mycobacterium smegmatis strain to explore its role in host pathogen interactions. Over expression of Rv1273c resulted in enhanced intracellular survival in macrophage as well as modified cell wall architecture. We found altered colony morphology and cell surface properties that might be linked with remodelling of bacterial cell wall which may help in the intracellular survival of mycobacterium. However, the enhanced intracellular survival was not found to be the consequence of an increased resistance to intracellular stresses. The activation of macrophage by Rv1273c was associated with perturbed cytokine production. Pharmacological inhibition experiment and western immunoblotting suggested that this altered cytokine profile was mediated possibly by NF-kB and p38 pathway in macrophage. Overall, the present findings indicated that Rv1273c enhanced mycobacterium persistence and mediated the evasion of immune responses during infection.
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Affiliation(s)
- Smita Gupta
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Arun Kumar
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Kamal Singh
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Richa Kumari
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ajay Sharma
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Rakesh K Singh
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Satyendra K Pandey
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Shampa Anupurba
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
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23
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Insights into the Physiology and Metabolism of a Mycobacterial Cell in an Energy-Compromised State. J Bacteriol 2019; 201:JB.00210-19. [PMID: 31285242 DOI: 10.1128/jb.00210-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/02/2019] [Indexed: 12/16/2022] Open
Abstract
Mycobacterium tuberculosis, a bacterium that causes tuberculosis, poses a serious threat, especially due to the emergence of drug-resistant strains. M. tuberculosis and other mycobacterial species, such as M. smegmatis, are known to generate an inadequate amount of energy by substrate-level phosphorylation and mandatorily require oxidative phosphorylation (OXPHOS) for their growth and metabolism. Hence, antibacterial drugs, such as bedaquiline, targeting the multisubunit ATP synthase complex, which is required for OXPHOS, have been developed with the aim of eliminating pathogenic mycobacteria. Here, we explored the influence of suboptimal OXPHOS on the physiology and metabolism of M. smegmatis M. smegmatis harbors two identical copies of atpD, which codes for the β subunit of ATP synthase. We show that upon deletion of one copy of atpD (M. smegmatis ΔatpD), M. smegmatis synthesizes smaller amounts of ATP and enters into an energy-compromised state. The mutant displays remarkable phenotypic and physiological differences from the wild type, such as respiratory slowdown, reduced biofilm formation, lesser amounts of cell envelope polar lipids, and increased antibiotic sensitivity compared to the wild type. Additionally, M. smegmatis ΔatpD overexpresses genes belonging to the dormancy operon, the β-oxidation pathway, and the glyoxylate shunt, suggesting that the mutant adapts to a low energy state by switching to alternative pathways to produce energy. Interestingly, M. smegmatis ΔatpD shows significant phenotypic, metabolic, and physiological similarities with bedaquiline-treated wild-type M. smegmatis We believe that the identification and characterization of key metabolic pathways functioning during an energy-compromised state will enhance our understanding of bacterial adaptation and survival and will open newer avenues in the form of drug targets that may be used in the treatment of mycobacterial infections.IMPORTANCE M. smegmatis generates an inadequate amount of energy by substrate-level phosphorylation and mandatorily requires oxidative phosphorylation (OXPHOS) for its growth and metabolism. Here, we explored the influence of suboptimal OXPHOS on M. smegmatis physiology and metabolism. M. smegmatis harbors two identical copies of the atpD gene, which codes for the ATP synthase β subunit. Here, we carried out the deletion of only one copy of atpD in M. smegmatis to understand the bacterial survival response in an energy-deprived state. M. smegmatis ΔatpD shows remarkable phenotypic, metabolic, and physiological differences from the wild type. Our study thus establishes M. smegmatis ΔatpD as an energy-compromised mycobacterial strain, highlights the importance of ATP synthase in mycobacterial physiology, and further paves the way for the identification of novel antimycobacterial drug targets.
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Abstract
Free-living bacteria can assemble into multicellular structures called biofilms. Biofilms help bacteria tolerate multiple stresses, including antibiotics and the host immune system. Nontuberculous mycobacteria are a group of emerging opportunistic pathogens that utilize biofilms to adhere to household plumbing and showerheads and to avoid phagocytosis by host immune cells. Typically, bacteria regulate biofilm formation by controlling expression of adhesive structures to attach to surfaces and other bacterial cells. Mycobacteria harbor a unique cell wall built chiefly of long-chain mycolic acids that confers hydrophobicity and has been thought to cause constitutive aggregation in liquid media. Here we show that aggregation is instead a regulated process dictated by the balance of available carbon and nitrogen. Understanding that mycobacteria utilize metabolic cues to regulate the transition between planktonic and aggregated cells reveals an inroad to controlling biofilm formation through targeted therapeutics. Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens that colonize household water systems and cause chronic lung infections in susceptible patients. The ability of NTM to form surface-attached biofilms in the nonhost environment and corded aggregates in vivo is important to their ability to persist in both contexts. Underlying the development of these multicellular structures is the capacity of mycobacterial cells to adhere to one another. Unlike most other bacteria, NTM spontaneously and constitutively aggregate in vitro, hindering our ability to understand the transition between planktonic and aggregated cells. While culturing a model NTM, Mycobacterium smegmatis, in rich medium, we fortuitously discovered that planktonic cells accumulate after ∼3 days of growth. By providing selective pressure for bacteria that disperse earlier, we isolated a strain with two mutations in the oligopeptide permease operon (opp). A mutant lacking the opp operon (Δopp) disperses earlier than wild type (WT) due to a defect in nutrient uptake. Experiments with WT M. smegmatis revealed that growth as aggregates is favored when carbon is replete, but under conditions of low available carbon relative to available nitrogen, M. smegmatis grows as planktonic cells. By adjusting carbon and nitrogen sources in defined medium, we tuned the cellular C/N ratio such that M. smegmatis grows either as aggregates or as planktonic cells. C/N-mediated aggregation regulation is widespread among NTM with the possible exception of rough-colony Mycobacterium abscessus isolates. Altogether, we show that NTM aggregation is a controlled process that is governed by the relative availability of carbon and nitrogen for metabolism.
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25
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Ruangkiattikul N, Rys D, Abdissa K, Rohde M, Semmler T, Tegtmeyer PK, Kalinke U, Schwarz C, Lewin A, Goethe R. Type I interferon induced by TLR2-TLR4-MyD88-TRIF-IRF3 controls Mycobacterium abscessus subsp. abscessus persistence in murine macrophages via nitric oxide. Int J Med Microbiol 2019; 309:307-318. [PMID: 31178418 DOI: 10.1016/j.ijmm.2019.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/08/2019] [Accepted: 05/31/2019] [Indexed: 12/15/2022] Open
Abstract
Mycobacterium abscessus (MAB) is an emerging, rapidly growing non-tuberculous Mycobacterium causing therapy-resistant pulmonary disease especially in patients with cystic fibrosis (CF). Smooth and rough colony type MAB can be isolated from infected patients whereby rough colony type MAB are more often associated with severe disease. Disease severity is also associated with an alternated type I interferon (IFN-I) response of the MAB-infected patients. However the relevance of this response for the outcome of MAB infection is still unknown. In this study, we analyzed the IFNβ expression of murine macrophages infected with a MAB rough colony strain (MAB-R) isolated from a patient with progressive CF and compared it to macrophages infected with the MAB smooth colony type reference strain (MAB-S). We found that MAB-R infected macrophages expressed significantly more IFNβ mRNA and protein than MAB-S infected macrophages. Higher IFNβ induction by MAB-R was associated with higher TNF expression and intracellular killing while low IFNβ induction was associated with lower TNF expression and persistence of MAB-S. IFNβ induction was independent of the intracellular cGAS-STING recognition pathway. MAB appeared to be recognized extracellularly and induced IFNβ expression via TLR2-TLR4-MyD88-TRIF-IRF3 dependent pathways. By using macrophages lacking the IFN-I receptor we demonstrate that MAB induced IFN-I response essentially contributed to restricting MAB-R and MAB-S infections by activating macrophage Nos2 expression and nitric oxide production. Thus IFN-I seem to influence the intrinsic ability of macrophages to control MAB infections. As MAB persists over long time periods in susceptible patients, our findings suggest that virulence of MAB strains is promoted by an insufficient IFN-I response of the host.
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Affiliation(s)
| | - Doris Rys
- Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ketema Abdissa
- Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Torsten Semmler
- NG1 Microbial Genomics, Robert Koch Institute, Berlin, Germany
| | - Pia-K Tegtmeyer
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, A Joint Venture Between The Helmholtz Centre for Infection Research, Braunschweig, and The Hannover Medical School, Hannover, Germany
| | - Ulrich Kalinke
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, A Joint Venture Between The Helmholtz Centre for Infection Research, Braunschweig, and The Hannover Medical School, Hannover, Germany
| | - Carsten Schwarz
- Department of Pediatric Pneumonology and Immunology, Division of Cystic Fibrosis, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Astrid Lewin
- FG16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Ralph Goethe
- Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany.
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Palčeková Z, Angala SK, Belardinelli JM, Eskandarian HA, Joe M, Brunton R, Rithner C, Jones V, Nigou J, Lowary TL, Gilleron M, McNeil M, Jackson M. Disruption of the SucT acyltransferase in Mycobacterium smegmatis abrogates succinylation of cell envelope polysaccharides. J Biol Chem 2019; 294:10325-10335. [PMID: 31110045 DOI: 10.1074/jbc.ra119.008585] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/14/2019] [Indexed: 12/22/2022] Open
Abstract
Similar to other prokaryotes, mycobacteria decorate their major cell envelope glycans with minor covalent substituents whose biological significance remains largely unknown. We report on the discovery of a mycobacterial enzyme, named here SucT, that adds succinyl groups to the arabinan domains of both arabinogalactan (AG) and lipoarabinomannan (LAM). Disruption of the SucT-encoding gene in Mycobacterium smegmatis abolished AG and LAM succinylation and altered the hydrophobicity and rigidity of the cell envelope of the bacilli without significantly altering AG and LAM biosynthesis. The changes in the cell surface properties of the mutant were consistent with earlier reports of transposon mutants of the closely related species Mycobacterium marinum and Mycobacterium avium harboring insertions in the orthologous gene whose ability to microaggregate and form biofilms were altered. Our findings point to an important role of SucT-mediated AG and LAM succinylation in modulating the cell surface properties of mycobacteria.
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Affiliation(s)
- Zuzana Palčeková
- From the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682
| | - Shiva K Angala
- From the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682
| | - Juan Manuel Belardinelli
- From the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682
| | - Haig A Eskandarian
- the Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne VD, Switzerland
| | - Maju Joe
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Richard Brunton
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Christopher Rithner
- the Central Instrumentation Facility, Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, and
| | - Victoria Jones
- From the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682
| | - Jérôme Nigou
- the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 Route de Narbonne, 31077 Toulouse, France
| | - Todd L Lowary
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Martine Gilleron
- the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 Route de Narbonne, 31077 Toulouse, France
| | - Michael McNeil
- From the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682
| | - Mary Jackson
- From the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682,
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27
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Di Capua CB, Belardinelli JM, Buchieri MV, Bortolotti A, Franceschelli JJ, Morbidoni HR. Deletion of MSMEG_1350 in Mycobacterium smegmatis causes loss of epoxy-mycolic acids, fitness alteration at low temperature and resistance to a set of mycobacteriophages. MICROBIOLOGY-SGM 2018; 164:1567-1582. [PMID: 30311878 DOI: 10.1099/mic.0.000734] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mycobacterium smegmatis is intrinsically resistant to thiacetazone, an anti-tubercular thiourea; however we report here that it causes a mild inhibition in growth in liquid medium. Since mycolic acid biosynthesis was affected, we cloned and expressed Mycobacterium smegmatis mycolic acid methyltransferases, postulated as targets for thiacetazone in other mycobacterial species. During this analysis we identified MSMEG_1350 as the methyltransferase involved in epoxy mycolic acid synthesis since its deletion led to their total loss. Phenotypic characterization of the mutant strain showed colony morphology alterations at all temperatures, reduced growth and a slightly increased susceptibility to SDS, lipophilic and large hydrophilic drugs at 20 °C with little effect at 37 °C. No changes were detected between parental and mutant strains in biofilm formation, sliding motility or sedimentation rate. Intriguingly, we found that several mycobacteriophages severely decreased their ability to form plaques in the mutant strain. Taken together our results prove that, in spite of being a minor component of the mycolic acid pool, epoxy-mycolates are required for a proper assembly and functioning of the cell envelope. Further studies are warranted to decipher the role of epoxy-mycolates in the M. smegmatis cell envelope.
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Affiliation(s)
- Cecilia B Di Capua
- Laboratorio de Microbiología Molecular, Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Juan M Belardinelli
- Laboratorio de Microbiología Molecular, Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina.,‡Present address: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - María V Buchieri
- Laboratorio de Microbiología Molecular, Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Ana Bortolotti
- Laboratorio de Microbiología Molecular, Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Jorgelina J Franceschelli
- Laboratorio de Microbiología Molecular, Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Héctor R Morbidoni
- Laboratorio de Microbiología Molecular, Cátedra de Microbiología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
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28
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Guha S, Udupa S, Ahmed W, Nagaraja V. Rewired Downregulation of DNA Gyrase Impacts Cell Division, Expression of Topology Modulators, and Transcription in Mycobacterium smegmatis. J Mol Biol 2018; 430:4986-5001. [PMID: 30316784 DOI: 10.1016/j.jmb.2018.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 09/22/2018] [Accepted: 10/02/2018] [Indexed: 10/28/2022]
Abstract
DNA gyrase, essential for DNA replication and transcription, has traditionally been studied in vivo by treatments that inhibit the enzyme activity. Due to its indispensable function, gyrA and gyrB deletions cannot be generated. The coumarin inhibitors of gyrase induce the supercoiling-sensitive gyrase promoter by a mechanism termed relaxation-stimulated transcription. Hence, to study the effect of sustained reduction in gyrase levels, a conditional-knockdown strain was generated in Mycobacterium smegmatis such that gyrase expression was controlled by a supercoiling non-responsive regulatory circuit. Decreasing intracellular gyrase protein levels beyond 50% affected cell growth. Reduced gyrase levels in the reprogrammed gyr operon caused chromosome relaxation, diffuse nucleoid structure, cell elongation, and altered gene expression. The key cell division protein, ftsZ, was severely reduced in the elongated cells, indicating a link between gyrase and cell division. Low levels of gyrase resulted in low compensatory expression of topoisomerase I and elevated expression of topology modulators hupB and lsr2. Altered supercoiling due to gyrase depletion caused corresponding changes in the RNA polymerase density on transcription units leading to their altered transcription. The enhanced susceptibility of the knockdown strain to anti-tubercular drugs suggests its utility for screening new molecules that may act synergistically with gyrase inhibitors.
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Affiliation(s)
- Sarmistha Guha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Shubha Udupa
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
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29
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Two dd-Carboxypeptidases from Mycobacterium smegmatis Affect Cell Surface Properties through Regulation of Peptidoglycan Cross-Linking and Glycopeptidolipids. J Bacteriol 2018; 200:JB.00760-17. [PMID: 29735762 DOI: 10.1128/jb.00760-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 04/25/2018] [Indexed: 11/20/2022] Open
Abstract
During the peptidoglycan (PG) maturation of mycobacteria, the glycan strands are interlinked by both 3-3 (between two meso-diaminopimelic acids [meso-DAPs]) and 4-3 cross-links (between d-Ala and meso-DAP), though there is a predominance (60 to 80%) of 3-3 cross-links. The dd-carboxypeptidases (dd-CPases) act on pentapeptides to generate tetrapeptides that are used by ld-transpeptidases as substrates to form 3-3 cross-links. Therefore, dd-CPases play a crucial role in mycobacterial PG cross-link formation. However, the physiology of dd-CPases in mycobacteria is relatively unexplored. In this study, we deleted two dd-CPase genes, msmeg_2433 and msmeg_2432, both individually and in combination, from Mycobacterium smegmatis mc2155. Though the single dd-CPase gene deletions had no significant impact on the mycobacterial physiology, many interesting functional alterations were observed in the double-deletion mutant, viz, a predominance in PG cross-link formation was shifted from 3-3 cross-links to 4-3, cell surface glycopeptidolipid (GPL) expression was reduced, and susceptibility to β-lactams and antitubercular agents was enhanced. Moreover, the survival rate of the double mutant within murine macrophages was higher than that of the parent. Interestingly, the complementation with any one of the dd-CPase genes could restore the wild-type phenotype. In a nutshell, we infer that the altered ratio of 4-3 to 3-3 PG cross-links might have influenced the expression of surface GPLs, colony morphology, biofilm formation, drug susceptibility, and subsistence of the cells within macrophages.IMPORTANCE The glycan strands in mycobacterial peptidoglycan (PG) are interlinked by both 3-3 and 4-3 cross-links. The dd-CPases generate tetrapeptides by acting on the pentapeptides, and ld-transpeptidases use tetrapeptides as substrates to form 3-3 cross-links. In this study, we showed that simultaneous deletions of two dd-CPases alter the nature of PG cross-linking from 3-3 cross-links to 4-3 cross-links. The deletions subsequently decrease the expression of glycopeptidolipids (significant surface lipid present in many nontuberculous mycobacteria, including Mycobacterium smegmatis) and affect other physiological parameters, like cell morphology, growth rate, biofilm formation, antibiotic susceptibility, and survival within murine macrophages. Thus, unraveling the physiology of dd-CPases might help us design antimycobacterial therapeutics in the future.
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30
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Kim SW, Subhadra B, Whang J, Back YW, Bae HS, Kim HJ, Choi CH. Clinical Mycobacterium abscessus strain inhibits autophagy flux and promotes its growth in murine macrophages. Pathog Dis 2018; 75:4259640. [PMID: 29044406 DOI: 10.1093/femspd/ftx107] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/25/2017] [Indexed: 02/07/2023] Open
Abstract
Autophagy is known to be a vital homeostatic defense process that controls mycobacterial infection. However, the relationship between autophagy response and the virulence of Mycobacterium abscessus strain UC22 has not been reported. Here, we demonstrate that M. abscessus induces autophagy and inhibits autophagy flux in murine macrophages. Further, the rough variant of M. abscessus, UC22 that is a highly virulent clinical isolate, significantly inhibited autophagic flux than the smooth variant of M. abscessus ATCC 19977. In addition, it was noticed that the intracellular survival of UC22 is significantly enhanced by blocking the autophagosome-lysosome fusion in macrophages compared to the smooth variant. However, Mycobacterium smegmatis did not block autophagy flux in murine macrophages. Besides, we confirmed that the lipid components of M. abscessus UC22 play a role in autophagosome formation. These data suggest that the virulent M. abscessus might be able to survive and grow within autophagosomes by preventing the autophagosome-lysosome fusion and their clearance from the cells.
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Affiliation(s)
- Seong-Woo Kim
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, 266 Munwha-ro, Jung-gu, Daejeon 35015, Republic of Korea
| | - Bindu Subhadra
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, 266 Munwha-ro, Jung-gu, Daejeon 35015, Republic of Korea
| | - Jake Whang
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, 266 Munwha-ro, Jung-gu, Daejeon 35015, Republic of Korea
| | - Yong Woo Back
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, 266 Munwha-ro, Jung-gu, Daejeon 35015, Republic of Korea
| | - Hyun Shik Bae
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, 266 Munwha-ro, Jung-gu, Daejeon 35015, Republic of Korea
| | - Hwa-Jung Kim
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, 266 Munwha-ro, Jung-gu, Daejeon 35015, Republic of Korea
| | - Chul Hee Choi
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, 266 Munwha-ro, Jung-gu, Daejeon 35015, Republic of Korea
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31
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Lefebvre C, Boulon R, Ducoux M, Gavalda S, Laval F, Jamet S, Eynard N, Lemassu A, Cam K, Bousquet MP, Bardou F, Burlet-Schiltz O, Daffé M, Quémard A. HadD, a novel fatty acid synthase type II protein, is essential for alpha- and epoxy-mycolic acid biosynthesis and mycobacterial fitness. Sci Rep 2018; 8:6034. [PMID: 29662082 PMCID: PMC5902629 DOI: 10.1038/s41598-018-24380-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 04/03/2018] [Indexed: 02/05/2023] Open
Abstract
Mycolic acids (MAs) have a strategic location within the mycobacterial envelope, deeply influencing its architecture and permeability, and play a determinant role in the pathogenicity of mycobacteria. The fatty acid synthase type II (FAS-II) multienzyme system is involved in their biosynthesis. A combination of pull-downs and proteomics analyses led to the discovery of a mycobacterial protein, HadD, displaying highly specific interactions with the dehydratase HadAB of FAS-II. In vitro activity assays and homology modeling showed that HadD is, like HadAB, a hot dog folded (R)-specific hydratase/dehydratase. A hadD knockout mutant of Mycobacterium smegmatis produced only the medium-size alpha’-MAs. Data strongly suggest that HadD is involved in building the third meromycolic segment during the late FAS-II elongation cycles, leading to the synthesis of the full-size alpha- and epoxy-MAs. The change in the envelope composition induced by hadD inactivation strongly altered the bacterial fitness and capacities to aggregate, assemble into colonies or biofilms and spread by sliding motility, and conferred a hypersensitivity to the firstline antimycobacterial drug rifampicin. This showed that the cell surface properties and the envelope integrity were greatly affected. With the alarmingly increasing case number of nontuberculous mycobacterial diseases, HadD appears as an attractive target for drug development.
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Affiliation(s)
- Cyril Lefebvre
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Richard Boulon
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Manuelle Ducoux
- Département Biologie Structurale & Biophysique, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Sabine Gavalda
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Françoise Laval
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Stevie Jamet
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Nathalie Eynard
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Anne Lemassu
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Kaymeuang Cam
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Marie-Pierre Bousquet
- Département Biologie Structurale & Biophysique, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Fabienne Bardou
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Odile Burlet-Schiltz
- Département Biologie Structurale & Biophysique, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Mamadou Daffé
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Annaïk Quémard
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France.
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Vijay S, Hai HT, Thu DDA, Johnson E, Pielach A, Phu NH, Thwaites GE, Thuong NTT. Ultrastructural Analysis of Cell Envelope and Accumulation of Lipid Inclusions in Clinical Mycobacterium tuberculosis Isolates from Sputum, Oxidative Stress, and Iron Deficiency. Front Microbiol 2018; 8:2681. [PMID: 29379477 PMCID: PMC5770828 DOI: 10.3389/fmicb.2017.02681] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/22/2017] [Indexed: 11/13/2022] Open
Abstract
Introduction: Mycobacteria have several unique cellular characteristics, such as multiple cell envelope layers, elongation at cell poles, asymmetric cell division, and accumulation of intracytoplasmic lipid inclusions, which contributes to their survival under stress conditions. However, the understanding of these characteristics in clinical Mycobacterium tuberculosis (M. tuberculosis) isolates and under host stress is limited. We previously reported the influence of host stress on the cell length distribution in a large set of clinical M. tuberculosis isolates (n = 158). Here, we investigate the influence of host stress on the cellular ultrastructure of few clinical M. tuberculosis isolates (n = 8) from that study. The purpose of this study is to further understand the influence of host stress on the cellular adaptations of clinical M. tuberculosis isolates. Methods: We selected few M. tuberculosis isolates (n = 8) for analyzing the cellular ultrastructure ex vivo in sputum and under in vitro stress conditions by transmission electron microscopy. The cellular adaptations of M. tuberculosis in sputum were correlated with the ultrastructure of antibiotic sensitive and resistant isolates in liquid culture, under oxidative stress, iron deficiency, and exposure to isoniazid. Results: In sputum, M. tuberculosis accumulated intracytoplasmic lipid inclusions. In liquid culture, clinical M. tuberculosis revealed isolate to isolate variation in the extent of intracytoplasmic lipid inclusions, which were absent in the laboratory strain H37Rv. Oxidative stress, iron deficiency, and exposure to isoniazid increased the accumulation of lipid inclusions and decreased the thickness of the cell envelope electron transparent layer in M. tuberculosis cells. Furthermore, intracytoplasmic compartments were observed in iron deficient cells. Conclusion: Our ultrastructural analysis has revealed significant influence of host stress on the cellular adaptations in clinical M. tuberculosis isolates. These adaptations may contribute to the survival of M. tuberculosis under host and antibiotic stress conditions. Variation in the cellular adaptations among clinical M. tuberculosis isolates may correlate with their ability to persist in tuberculosis patients during antibiotic treatment. These observations indicate the need for further analyzing these cellular adaptations in a large set of clinical M. tuberculosis isolates. This will help to determine the significance of these cellular adaptations in the tuberculosis treatment.
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Affiliation(s)
- Srinivasan Vijay
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Hoang T Hai
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Do D A Thu
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Errin Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Anna Pielach
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Nguyen H Phu
- Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Guy E Thwaites
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nguyen T T Thuong
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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33
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Dissecting the mycobacterial cell envelope and defining the composition of the native mycomembrane. Sci Rep 2017; 7:12807. [PMID: 28993692 PMCID: PMC5634507 DOI: 10.1038/s41598-017-12718-4] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/18/2017] [Indexed: 11/20/2022] Open
Abstract
The mycobacterial envelope is unique, containing the so-called mycomembrane (MM) composed of very-long chain fatty acids, mycolic acids (MA). Presently, the molecular composition of the MM remains unproven, due to the diversity of methods used for determining its composition. The plasma membranes (PM) and the native MM-containing cell walls (MMCW) of two rapid-growing mycobacterial species, Mycobacterium aurum and M. smegmatis, were isolated from their cell lysates by differential ultracentrifugation. Transmission electron microscopy and biochemical analyses demonstrated that the two membranes were virtually pure. Bottom-up quantitative proteomics study indicated a different distribution of more than 2,100 proteins between the PM and MMCW. Among these, the mannosyltransferase PimB, galactofuranosyltransferase GlfT2, Cytochrome p450 and ABC transporter YjfF, were most abundant in the PM, which also contain lipoglycans, phospholipids, including phosphatidylinositol mannosides, and only a tiny amount of other glycolipids. Antigen85 complex proteins, porins and the putative transporters MCE protein family were mostly found in MMCW fraction that contains MA esterifying arabinogalactan, constituting the inner leaflet of MM. Glycolipids, phospholipids and lipoglycans, together with proteins, presumably composed the outer leaflet of the MM, a lipid composition that differs from that deduced from the widely used extraction method of mycobacterial cells with dioctylsulfosuccinate sodium.
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34
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Yang Y, Thomas J, Li Y, Vilchèze C, Derbyshire KM, Jacobs WR, Ojha AK. Defining a temporal order of genetic requirements for development of mycobacterial biofilms. Mol Microbiol 2017. [PMID: 28628249 DOI: 10.1111/mmi.13734] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Most mycobacterial species spontaneously form biofilms, inducing unique growth physiologies and reducing drug sensitivity. Biofilm growth progresses through three genetically programmed stages: substratum attachment, intercellular aggregation and architecture maturation. Growth of Mycobacterium smegmatis biofilms requires multiple factors including a chaperonin (GroEL1) and a nucleoid-associated protein (Lsr2), although how their activities are linked remains unclear. Here it is shown that Lsr2 participates in intercellular aggregation, but substratum attachment of Lsr2 mutants is unaffected, thereby genetically distinguishing these developmental stages. Further, a suppressor mutation in a glycopeptidolipid synthesis gene (mps) that results in hyperaggregation of cells and fully restores the form and functions of Δlsr2 mutant biofilms was identified. Suppression by the mps mutation is specific to Δlsr2; it does not rescue the maturation-deficient biofilms of a ΔgroEL1 mutant, thereby differentiating the process of aggregation from maturation. Gene expression analysis supports a stepwise process of maturation, highlighted by temporally separated, transient inductions of iron and nitrogen import genes. Furthermore, GroEL1 activity is required for induction of nitrogen, but not iron, import genes. Together, the findings begin to define molecular checkpoints during development of mycobacterial biofilms.
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Affiliation(s)
- Yong Yang
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Joseph Thomas
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yunlong Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Keith M Derbyshire
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - William R Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.,Howard Hughes Medical Institute, Bronx, NY, USA
| | - Anil K Ojha
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA.,Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA, USA
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35
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Phillips D, Harrison J, Richards SJ, Mitchell DE, Tichauer E, Hubbard ATM, Guy C, Hands-Portman I, Fullam E, Gibson MI. Evaluation of the Antimicrobial Activity of Cationic Polymers against Mycobacteria: Toward Antitubercular Macromolecules. Biomacromolecules 2017; 18:1592-1599. [PMID: 28365981 PMCID: PMC5435458 DOI: 10.1021/acs.biomac.7b00210] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/28/2017] [Indexed: 11/29/2022]
Abstract
Antimicrobial resistance is a global healthcare problem with a dwindling arsenal of usable drugs. Tuberculosis, caused by Mycobacterium tuberculosis, requires long-term combination therapy and multi- and totally drug resistant strains have emerged. This study reports the antibacterial activity of cationic polymers against mycobacteria, which are distinguished from other Gram-positive bacteria by their unique cell wall comprising a covalently linked mycolic acid-arabinogalactan-peptidoglycan complex (mAGP), interspersed with additional complex lipids which helps them persist in their host. The present study finds that poly(dimethylaminoethyl methacrylate) has particularly potent antimycobacterial activity and high selectivity over two Gram-negative strains. Removal of the backbone methyl group (poly(dimethylaminoethyl acrylate)) decreased antimycobacterial activity, and poly(aminoethyl methacrylate) also had no activity against mycobacteria. Hemolysis assays revealed poly(dimethylaminoethyl methacrylate) did not disrupt red blood cell membranes. Interestingly, poly(dimethylaminoethyl methacrylate) was not found to permeabilize mycobacterial membranes, as judged by dye exclusion assays, suggesting the mode of action is not simple membrane disruption, supported by electron microscopy analysis. These results demonstrate that synthetic polycations, with the correctly tuned structure are useful tools against mycobacterial infections, for which new drugs are urgently required.
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Affiliation(s)
- Daniel
J. Phillips
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - James Harrison
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Sarah-Jane Richards
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Daniel E. Mitchell
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Esther Tichauer
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Alasdair T. M. Hubbard
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Collette Guy
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Ian Hands-Portman
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Elizabeth Fullam
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Matthew I. Gibson
- Department of Chemistry, School of Life Sciences, and Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
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36
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Jankute M, Nataraj V, Lee OYC, Wu HHT, Ridell M, Garton NJ, Barer MR, Minnikin DE, Bhatt A, Besra GS. The role of hydrophobicity in tuberculosis evolution and pathogenicity. Sci Rep 2017; 7:1315. [PMID: 28465507 PMCID: PMC5431016 DOI: 10.1038/s41598-017-01501-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/29/2017] [Indexed: 12/24/2022] Open
Abstract
The evolution of tubercle bacilli parallels a route from environmental Mycobacterium kansasii, through intermediate "Mycobacterium canettii", to the modern Mycobacterium tuberculosis complex. Cell envelope outer membrane lipids change systematically from hydrophilic lipooligosaccharides and phenolic glycolipids to hydrophobic phthiocerol dimycocerosates, di- and pentaacyl trehaloses and sulfoglycolipids. Such lipid changes point to a hydrophobic phenotype for M. tuberculosis sensu stricto. Using Congo Red staining and hexadecane-aqueous buffer partitioning, the hydrophobicity of rough morphology M. tuberculosis and Mycobacterium bovis strains was greater than smooth "M. canettii" and M. kansasii. Killed mycobacteria maintained differential hydrophobicity but defatted cells were similar, indicating that outer membrane lipids govern overall hydrophobicity. A rough M. tuberculosis H37Rv ΔpapA1 sulfoglycolipid-deficient mutant had significantly diminished Congo Red uptake though hexadecane-aqueous buffer partitioning was similar to H37Rv. An M. kansasii, ΔMKAN27435 partially lipooligosaccharide-deficient mutant absorbed marginally more Congo Red dye than the parent strain but was comparable in partition experiments. In evolving from ancestral mycobacteria, related to "M. canettii" and M. kansasii, modern M. tuberculosis probably became more hydrophobic by increasing the proportion of less polar lipids in the outer membrane. Importantly, such a change would enhance the capability for aerosol transmission, affecting virulence and pathogenicity.
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Affiliation(s)
- Monika Jankute
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Vijayashankar Nataraj
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Oona Y-C Lee
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Houdini H T Wu
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Malin Ridell
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Natalie J Garton
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Michael R Barer
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - David E Minnikin
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Apoorva Bhatt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.
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37
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Zanfardino A, Migliardi A, D'Alonzo D, Lombardi A, Varcamonti M, Cordone A. Inactivation of MSMEG_0412 gene drastically affects surface related properties of Mycobacterium smegmatis. BMC Microbiol 2016; 16:267. [PMID: 27825305 PMCID: PMC5101647 DOI: 10.1186/s12866-016-0888-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 11/04/2016] [Indexed: 01/03/2023] Open
Abstract
Background The outermost layer of mycobacterial cell wall is rich in lipids and glycolipids, surface molecules which differ among species. Mycobacterium smegmatis, an attractive model for the study of both pathogenic and non-pathogenic mycobacteria, presents glycopeptidolipids (GPLs). All the genes necessary for the biosynthesis of such molecules are clustered in a single region of 65 kb and among them, the msmeg_0412 gene has not been characterized yet. Here we report the isolation and subsequent analysis of a MSMEG_0412 null mutant strain. Results The inactivation of the msmeg_0412 gene had a drastic impact on bacterial surface properties which resulted in the lack of sliding motility, altered biofilm formation and enhanced drug susceptibility. The GPLs analysis showed that the observed mutant phenotype was due to GPLs deficiencies on the mycobacterial cell wall. In addition, we report that the expression of the gene is enhanced in the presence of lipidic substrates and that the encoded protein has a membrane localization. Conclusion msmeg_0412 plays a crucial role for GPLs production and translocation on M. smegmatis surface. Its deletion alters the surface properties and the antibiotic permeability of the mycobacterial cell barrier. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0888-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anna Zanfardino
- Department of Biology, University of Naples "Federico II", Via Cintia, 80126, Naples, Italy
| | - Adriana Migliardi
- Department of Biology, University of Naples "Federico II", Via Cintia, 80126, Naples, Italy
| | - Daniele D'Alonzo
- Department of Chemical Sciences, University of Naples "Federico II", Via Cintia, 80126, Naples, Italy
| | - Angela Lombardi
- Department of Chemical Sciences, University of Naples "Federico II", Via Cintia, 80126, Naples, Italy
| | - Mario Varcamonti
- Department of Biology, University of Naples "Federico II", Via Cintia, 80126, Naples, Italy
| | - Angela Cordone
- Department of Biology, University of Naples "Federico II", Via Cintia, 80126, Naples, Italy.
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38
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Brambilla C, Llorens-Fons M, Julián E, Noguera-Ortega E, Tomàs-Martínez C, Pérez-Trujillo M, Byrd TF, Alcaide F, Luquin M. Mycobacteria Clumping Increase Their Capacity to Damage Macrophages. Front Microbiol 2016; 7:1562. [PMID: 27757105 PMCID: PMC5047892 DOI: 10.3389/fmicb.2016.01562] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/20/2016] [Indexed: 11/18/2022] Open
Abstract
The rough morphotypes of non-tuberculous mycobacteria have been associated with the most severe illnesses in humans. This idea is consistent with the fact that Mycobacterium tuberculosis presents a stable rough morphotype. Unlike smooth morphotypes, the bacilli of rough morphotypes grow close together, leaving no spaces among them and forming large aggregates (clumps). Currently, the initial interaction of macrophages with clumps remains unclear. Thus, we infected J774 macrophages with bacterial suspensions of rough morphotypes of M. abscessus containing clumps and suspensions of smooth morphotypes, primarily containing isolated bacilli. Using confocal laser scanning microscopy and electron microscopy, we observed clumps of at least five rough-morphotype bacilli inside the phagocytic vesicles of macrophages at 3 h post-infection. These clumps grew within the phagocytic vesicles, killing 100% of the macrophages at 72 h post-infection, whereas the proliferation of macrophages infected with smooth morphotypes remained unaltered at 96 h post-infection. Thus, macrophages phagocytose large clumps, exceeding the bactericidal capacities of these cells. Furthermore, proinflammatory cytokines and granuloma-like structures were only produced by macrophages infected with rough morphotypes. Thus, the present study provides a foundation for further studies that consider mycobacterial clumps as virulence factors.
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Affiliation(s)
- Cecilia Brambilla
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona Bellaterra, Spain
| | - Marta Llorens-Fons
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona Bellaterra, Spain
| | - Esther Julián
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona Bellaterra, Spain
| | - Estela Noguera-Ortega
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona Bellaterra, Spain
| | - Cristina Tomàs-Martínez
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona Bellaterra, Spain
| | - Miriam Pérez-Trujillo
- Servei de Ressonància Magnètica Nuclear and Departament de Química, Universitat Autònoma de Barcelona Bellaterra, Spain
| | - Thomas F Byrd
- Division of Infection Diseases, Depatment of Medicine, The University of New Mexico School of Medicine, Albuquerque NM, USA
| | - Fernando Alcaide
- Servei de Microbiologia, Hospital Universitari de Bellvitge-Institut d'Investigació Biomèdica de Bellvitge, Universitat de Barcelona Barcelona, Spain
| | - Marina Luquin
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona Bellaterra, Spain
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39
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Chen X, Wu B, Jayawardana KW, Hao N, Jayawardena HSN, Langer R, Jaklenec A, Yan M. Magnetic Multivalent Trehalose Glycopolymer Nanoparticles for the Detection of Mycobacteria. Adv Healthc Mater 2016; 5:2007-12. [PMID: 27283385 PMCID: PMC5242184 DOI: 10.1002/adhm.201600071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 05/11/2016] [Indexed: 01/29/2023]
Abstract
A multivalent trehalose-grafted poly(lactic acid) is synthesized and encapsulated with iron oxide magnetic nanoparticles. The magnetic micelles interact with Mycobacterium smegmatis to form orange clusters. Very little particle interaction is found on Staphylococcus epidermidis 35984 or Escherichia coli ORN 208. The presented new approach to the detection of mycobacteria does not require molecular biology reagents or sophisticated instruments.
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Affiliation(s)
- Xuan Chen
- Department of Chemistry, University of Massachusetts, Lowell, MA, 01854, USA
| | - Bin Wu
- Department of Chemistry, University of Massachusetts, Lowell, MA, 01854, USA
| | | | - Nanjing Hao
- Department of Chemistry, University of Massachusetts, Lowell, MA, 01854, USA
| | - H Surangi N Jayawardena
- David H. Koch Institute of Integrative Cancer Research Centre, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Robert Langer
- David H. Koch Institute of Integrative Cancer Research Centre, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Ana Jaklenec
- David H. Koch Institute of Integrative Cancer Research Centre, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Mingdi Yan
- Department of Chemistry, University of Massachusetts, Lowell, MA, 01854, USA
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40
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Noguera-Ortega E, Blanco-Cabra N, Rabanal RM, Sánchez-Chardi A, Roldán M, Guallar-Garrido S, Torrents E, Luquin M, Julián E. Mycobacteria emulsified in olive oil-in-water trigger a robust immune response in bladder cancer treatment. Sci Rep 2016; 6:27232. [PMID: 27265565 PMCID: PMC4893706 DOI: 10.1038/srep27232] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 05/17/2016] [Indexed: 12/22/2022] Open
Abstract
The hydrophobic composition of mycobacterial cell walls leads to the formation of clumps when attempting to resuspend mycobacteria in aqueous solutions. Such aggregation may interfere in the mycobacteria-host cells interaction and, consequently, influence their antitumor effect. To improve the immunotherapeutic activity of Mycobacterium brumae, we designed different emulsions and demonstrated their efficacy. The best formulation was initially selected based on homogeneity and stability. Both olive oil (OO)- and mineral oil-in-water emulsions better preserved the mycobacteria viability and provided higher disaggregation rates compared to the others. But, among both emulsions, the OO emulsion increased the mycobacteria capacity to induce cytokines’ production in bladder tumor cell cultures. The OO-mycobacteria emulsion properties: less hydrophobic, lower pH, more neutralized zeta potential, and increased affinity to fibronectin than non-emulsified mycobacteria, indicated favorable conditions for reaching the bladder epithelium in vivo. Finally, intravesical OO-M. brumae-treated mice showed a significantly higher systemic immune response, together with a trend toward increased tumor-bearing mouse survival rates compared to the rest of the treated mice. The physicochemical characteristics and the induction of a robust immune response in vitro and in vivo highlight the potential of the OO emulsion as a good delivery vehicle for the mycobacterial treatment of bladder cancer.
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Affiliation(s)
- Estela Noguera-Ortega
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Spain
| | - Núria Blanco-Cabra
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Spain
| | - Rosa Maria Rabanal
- Unitat de Patologia Murina i Comparada, Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Spain
| | | | - Mónica Roldán
- Servei de Microscopia, Universitat Autònoma de Barcelona, Spain
| | - Sandra Guallar-Garrido
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Spain
| | - Eduard Torrents
- Bacterial Infections and Antimicrobial Therapy group, Institute for Bioengineering of Catalonia (IBEC), Spain
| | - Marina Luquin
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Spain
| | - Esther Julián
- Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Spain
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41
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PE11, a PE/PPE family protein of Mycobacterium tuberculosis is involved in cell wall remodeling and virulence. Sci Rep 2016; 6:21624. [PMID: 26902658 PMCID: PMC4763214 DOI: 10.1038/srep21624] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 01/27/2016] [Indexed: 12/14/2022] Open
Abstract
The role of the unique proline-glutamic acid (PE)/proline-proline-glutamic acid (PPE) family of proteins in the pathophysiology and virulence of Mycobacterium tuberculosis is not clearly understood. One of the PE family proteins, PE11 (LipX or Rv1169c), specific to pathogenic mycobacteria is found to be over-expressed during infection of macrophages and in active TB patients. In this study, we report that M. smegmatis expressing PE11 (Msmeg-PE11) exhibited altered colony morphology and cell wall lipid composition leading to a marked increase in resistance against various environmental stressors and antibiotics. The cell envelope of Msmeg-PE11 also had greater amount of glycolipids and polar lipids. Msmeg-PE11 was found to have better survival rate in infected macrophages. Mice infected with Msmeg-PE11 had higher bacterial load, showed exacerbated organ pathology and mortality. The liver and lung of Msmeg-PE11-infected mice also had higher levels of IL-10, IL-4 and TNF-α cytokines, indicating a potential role of this protein in mycobacterial virulence.
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Abstract
This article summarizes what is currently known of the structures, physiological roles, involvement in pathogenicity, and biogenesis of a variety of noncovalently bound cell envelope lipids and glycoconjugates of Mycobacterium tuberculosis and other Mycobacterium species. Topics addressed in this article include phospholipids; phosphatidylinositol mannosides; triglycerides; isoprenoids and related compounds (polyprenyl phosphate, menaquinones, carotenoids, noncarotenoid cyclic isoprenoids); acyltrehaloses (lipooligosaccharides, trehalose mono- and di-mycolates, sulfolipids, di- and poly-acyltrehaloses); mannosyl-beta-1-phosphomycoketides; glycopeptidolipids; phthiocerol dimycocerosates, para-hydroxybenzoic acids, and phenolic glycolipids; mycobactins; mycolactones; and capsular polysaccharides.
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Singh AK, Dutta D, Singh V, Srivastava V, Biswas RK, Singh BN. Characterization of Mycobacterium smegmatis sigF mutant and its regulon: overexpression of SigF antagonist (MSMEG_1803) in M. smegmatis mimics sigF mutant phenotype, loss of pigmentation, and sensitivity to oxidative stress. Microbiologyopen 2015; 4:896-916. [PMID: 26434659 PMCID: PMC4694148 DOI: 10.1002/mbo3.288] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/15/2015] [Accepted: 08/18/2015] [Indexed: 12/22/2022] Open
Abstract
In Mycobacterium smegmatis, sigF is widely expressed during different growth stages and plays role in adaptation to stationary phase and oxidative stress. Using a sigF deletion mutant of M. smegmatis mc2155, we demonstrate that SigF is not essential for growth of bacterium. Deletion of sigF results in loss of carotenoid pigmentation which rendered increased susceptibility to H2O2 induced oxidative stress in M. smegmatis. SigF modulates the cell surface architecture and lipid biosynthesis extending the repertoire of SigF function in this species. M. smegmatis SigF regulon included variety of genes expressed during exponential and stationary phases of growth and those responsible for oxidative stress, lipid biosynthesis, energy, and central intermediary metabolism. Furthermore, we report the identification of a SigF antagonist, an anti‐sigma factor (RsbW), which upon overexpression in M. smegmatis wild type strain produced a phenotype similar to M. smegmatis mc2155 ΔsigF strain. The SigF‐anti‐SigF interaction is duly validated using bacterial two‐hybrid and pull down assays. In addition, anti‐sigma factor antagonists, RsfA and RsfB were identified and their interactions with anti‐sigma factor were experimentally validated. Identification of these proteins will help decode regulatory circuit of this alternate sigma factor.
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Affiliation(s)
- Anirudh K Singh
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Debashis Dutta
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Vandana Singh
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Vishal Srivastava
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Rajesh K Biswas
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Bhupendra N Singh
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
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Fujiwara N, Ohara N, Ogawa M, Maeda S, Naka T, Taniguchi H, Yamamoto S, Ayata M. Glycopeptidolipid of Mycobacterium smegmatis J15cs Affects Morphology and Survival in Host Cells. PLoS One 2015; 10:e0126813. [PMID: 25970481 PMCID: PMC4430512 DOI: 10.1371/journal.pone.0126813] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 04/08/2015] [Indexed: 11/18/2022] Open
Abstract
Mycobacterium smegmatis has been widely used as a mycobacterial infection model. Unlike the M. smegmatis mc2155 strain, M. smegmatis J15cs strain has the advantage of surviving for one week in murine macrophages. In our previous report, we clarified that the J15cs strain has deleted apolar glycopeptidolipids (GPLs) in the cell wall, which may affect its morphology and survival in host cells. In this study, the gene causing the GPL deletion in the J15cs strain was identified. The mps1-2 gene (MSMEG_0400-0402) correlated with GPL biosynthesis. The J15cs strain had 18 bps deleted in the mps1 gene compared to that of the mc2155 strain. The mps1-complemented J15cs mutant restored the expression of GPLs. Although the J15cs strain produces a rough and dry colony, the colony morphology of this mps1-complement was smooth like the mc2155 strain. The length in the mps1-complemented J15cs mutant was shortened by the expression of GPLs. In addition, the GPL-restored J15cs mutant did not survive as long as the parent J15cs strain in the murine macrophage cell line J774.1 cells. The results are direct evidence that the deletion of GPLs in the J15cs strain affects bacterial size, morphology, and survival in host cells.
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Affiliation(s)
- Nagatoshi Fujiwara
- Department of Food and Nutrition, Faculty of Contemporary Human Life Science, Tezukayama University, Nara City, Nara, Japan
- Department of Bacteriology, Osaka City University Graduate School of Medicine, Osaka City, Osaka, Japan
- * E-mail:
| | - Naoya Ohara
- Department of Oral Microbiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama City, Okayama, Japan
| | - Midori Ogawa
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu City, Fukuoka, Japan
| | - Shinji Maeda
- Molecular Epidemiology Division, Mycobacterium Reference Center, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose City, Tokyo, Japan
| | - Takashi Naka
- Department of Bacteriology, Osaka City University Graduate School of Medicine, Osaka City, Osaka, Japan
- MBR Co. Ltd., Toyonaka City, Osaka, Japan
| | - Hatsumi Taniguchi
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu City, Fukuoka, Japan
| | | | - Minoru Ayata
- Department of Virology, Osaka City University Graduate School of Medicine, Osaka City, Osaka, Japan
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CpsA, a LytR-CpsA-Psr Family Protein in Mycobacterium marinum, Is Required for Cell Wall Integrity and Virulence. Infect Immun 2015; 83:2844-54. [PMID: 25939506 DOI: 10.1128/iai.03081-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/20/2015] [Indexed: 12/28/2022] Open
Abstract
LytR-CpsA-Psr family proteins play an important role in bacterial cell wall integrity. Although the pathogenic relevance of LytR-CpsA-Psr family proteins has been studied in a few bacterial pathogens, their function in mycobacteria remains uncharacterized. In this work, a transposon insertion mutant (cpsA::Tn) of Mycobacterium marinum was studied. We found that inactivation of CpsA altered bacterial colony morphology, sliding motility, cell surface hydrophobicity, and cell wall permeability. Besides, the cpsA mutant exhibited a decreased arabinogalactan content, indicating that CpsA plays a role in cell wall assembly. Moreover, the mutant shows impaired growth within macrophage cell lines and is severely attenuated in zebrafish larvae and adult zebrafish. Taken together, our results indicated that CpsA, a previously uncharacterized protein, is important for mycobacterial cell wall integrity and is required for mycobacterial virulence.
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46
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Synthetic glycolipids and (p)ppGpp analogs: development of inhibitors for mycobacterial growth, biofilm and stringent response. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 842:309-27. [PMID: 25408352 DOI: 10.1007/978-3-319-11280-0_20] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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47
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Ahmed W, Menon S, Karthik PV, Nagaraja V. Reduction in DNA topoisomerase I level affects growth, phenotype and nucleoid architecture of Mycobacterium smegmatis. MICROBIOLOGY-SGM 2014; 161:341-353. [PMID: 25516959 DOI: 10.1099/mic.0.000014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The steady-state negative supercoiling of eubacterial genomes is maintained by the action of DNA topoisomerases. Topoisomerase distribution varies in different species of mycobacteria. While Mycobacterium tuberculosis (Mtb) contains a single type I (TopoI) and a single type II (Gyrase) enzyme, Mycobacterium smegmatis (Msm) and other members harbour additional relaxases. TopoI is essential for Mtb survival. However, the necessity of TopoI or other relaxases in Msm has not been investigated. To recognize the importance of TopoI for growth, physiology and gene expression of Msm, we have developed a conditional knock-down strain of TopoI in Msm. The TopoI-depleted strain exhibited extremely slow growth and drastic changes in phenotypic characteristics. The cessation of growth indicates the essential requirement of the enzyme for the organism in spite of having additional DNA relaxation enzymes in the cell. Notably, the imbalance in TopoI level led to the altered expression of topology modulatory proteins, resulting in a diffused nucleoid architecture. Proteomic and transcript analysis of the mutant indicated reduced expression of the genes involved in central metabolic pathways and core DNA transaction processes. RNA polymerase (RNAP) distribution on the transcription units was affected in the TopoI-depleted cells, suggesting global alteration in transcription. The study thus highlights the essential requirement of TopoI in the maintenance of cellular phenotype, growth characteristics and gene expression in mycobacteria. A decrease in TopoI level led to altered RNAP occupancy and impaired transcription elongation, causing severe downstream effects.
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Affiliation(s)
- Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Shruti Menon
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Pullela V Karthik
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Valakunja Nagaraja
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India.,Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
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Gajadeera C, Willby MJ, Green KD, Shaul P, Fridman M, Garneau-Tsodikova S, Posey JE, Tsodikov OV. Antimycobacterial activity of DNA intercalator inhibitors of Mycobacterium tuberculosis primase DnaG. J Antibiot (Tokyo) 2014; 68:153-7. [PMID: 25248725 DOI: 10.1038/ja.2014.131] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/29/2014] [Accepted: 08/13/2014] [Indexed: 11/09/2022]
Abstract
Owing to the rise in drug resistance in tuberculosis combined with the global spread of its causative pathogen, Mycobacterium tuberculosis (Mtb), innovative anti mycobacterial agents are urgently needed. Recently, we developed a novel primase-pyrophosphatase assay and used it to discover inhibitors of an essential Mtb enzyme, primase DnaG (Mtb DnaG), a promising and unexplored potential target for novel antituberculosis chemotherapeutics. Doxorubicin, an anthracycline antibiotic used as an anticancer drug, was found to be a potent inhibitor of Mtb DnaG. In this study, we investigated both inhibition of Mtb DnaG and the inhibitory activity against in vitro growth of Mtb and M. smegmatis (Msm) by other anthracyclines, daunorubicin and idarubicin, as well as by less cytotoxic DNA intercalators: aloe-emodin, rhein and a mitoxantrone derivative. Generally, low-μM inhibition of Mtb DnaG by the anthracyclines was correlated with their low-μM minimum inhibitory concentrations. Aloe-emodin displayed threefold weaker potency than doxorubicin against Mtb DnaG and similar inhibition of Msm (but not Mtb) in the mid-μM range, whereas rhein (a close analog of aloe-emodin) and a di-glucosylated mitoxantrone derivative did not show significant inhibition of Mtb DnaG or antimycobacterial activity. Taken together, these observations strongly suggest that several clinically used anthracyclines and aloe-emodin target mycobacterial primase, setting the stage for a more extensive exploration of this enzyme as an antibacterial target.
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Affiliation(s)
- Chathurada Gajadeera
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Melisa J Willby
- Division of Tuberculosis Elimination, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Keith D Green
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Pazit Shaul
- School of Chemistry, Tel Aviv University, Tel Aviv, Israel
| | - Micha Fridman
- School of Chemistry, Tel Aviv University, Tel Aviv, Israel
| | | | - James E Posey
- Division of Tuberculosis Elimination, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
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Quadri LEN. Biosynthesis of mycobacterial lipids by polyketide synthases and beyond. Crit Rev Biochem Mol Biol 2014; 49:179-211. [DOI: 10.3109/10409238.2014.896859] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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50
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Lavollay M, Dubée V, Heym B, Herrmann JL, Gaillard JL, Gutmann L, Arthur M, Mainardi JL. In vitro activity of cefoxitin and imipenem against Mycobacterium abscessus complex. Clin Microbiol Infect 2013; 20:O297-300. [PMID: 24112243 DOI: 10.1111/1469-0691.12405] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 09/17/2013] [Accepted: 09/18/2013] [Indexed: 11/30/2022]
Abstract
The in vitro activity of cefoxitin and imipenem was compared for 43 strains of the Mycobacterium abscessus complex, mostly isolated from cystic fibrosis patients. The MICs of imipenem were lower than those of cefoxitin, although the number of imipenem-resistant strains was higher according to the CLSI breakpoints. Strain comparisons indicated that the MICs of cefoxitin were significantly higher for Mycobacterium bolletii than for M. abscessus. The MICs of both β-lactams were higher for the rough morphotype than for the smooth morphotype. The clinical impact of the in vitro difference between the activity of imipenem and that of cefoxitin remains to be determined.
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Affiliation(s)
- M Lavollay
- INSERM, U872, LRMA, Equipe 12 du Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie, UMR S 872, Paris, France; Université Paris Descartes, UMR S 872, Paris, France; Service de Microbiologie, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
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