1
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Meyer FM, Bramkamp M. Cell wall synthesizing complexes in Mycobacteriales. Curr Opin Microbiol 2024; 79:102478. [PMID: 38653035 DOI: 10.1016/j.mib.2024.102478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/04/2024] [Accepted: 04/07/2024] [Indexed: 04/25/2024]
Abstract
Members of the order Mycobacteriales are distinguished by a characteristic diderm cell envelope, setting them apart from other Actinobacteria species. In addition to the conventional peptidoglycan cell wall, these organisms feature an extra polysaccharide polymer composed of arabinose and galactose, termed arabinogalactan. The nonreducing ends of arabinose are covalently linked to mycolic acids (MAs), forming the immobile inner leaflet of the highly hydrophobic MA membrane. The contiguous outer leaflet of the MA membrane comprises trehalose mycolates and various lipid species. Similar to all actinobacteria, Mycobacteriales exhibit apical growth, facilitated by a polar localized elongasome complex. A septal cell envelope synthesis machinery, the divisome, builds instead of the cell wall structures during cytokinesis. In recent years, a growing body of knowledge has emerged regarding the cell wall synthesizing complexes of Mycobacteriales., focusing particularly on three model species: Corynebacterium glutamicum, Mycobacterium smegmatis, and Mycobacterium tuberculosis.
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Affiliation(s)
- Fabian M Meyer
- Institute for General Microbiology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Marc Bramkamp
- Institute for General Microbiology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
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2
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Sparks IL, Kado T, Prithviraj M, Nijjer J, Yan J, Morita YS. Lipoarabinomannan mediates localized cell wall integrity during division in mycobacteria. Nat Commun 2024; 15:2191. [PMID: 38467648 PMCID: PMC10928101 DOI: 10.1038/s41467-024-46565-5] [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: 07/14/2023] [Accepted: 02/29/2024] [Indexed: 03/13/2024] Open
Abstract
The growth and division of mycobacteria, which include clinically relevant pathogens, deviate from that of canonical bacterial models. Despite their Gram-positive ancestry, mycobacteria synthesize and elongate a diderm envelope asymmetrically from the poles, with the old pole elongating more robustly than the new pole. The phosphatidylinositol-anchored lipoglycans lipomannan (LM) and lipoarabinomannan (LAM) are cell envelope components critical for host-pathogen interactions, but their physiological functions in mycobacteria remained elusive. In this work, using biosynthetic mutants of these lipoglycans, we examine their roles in maintaining cell envelope integrity in Mycobacterium smegmatis and Mycobacterium tuberculosis. We find that mutants defective in producing mature LAM fail to maintain rod cell shape specifically at the new pole and para-septal regions whereas a mutant that produces a larger LAM becomes multi-septated. Therefore, LAM plays critical and distinct roles at subcellular locations associated with division in mycobacteria, including maintenance of local cell wall integrity and septal placement.
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Affiliation(s)
- Ian L Sparks
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Takehiro Kado
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | | | - Japinder Nijjer
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Jing Yan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA.
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3
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Timkina E, Kulišová M, Palyzová A, Marešová H, Maťátková O, Řezanka T, Kolouchová IJ. Isolation and characterization of multiple-stress tolerant bacteria from radon springs. PLoS One 2024; 19:e0299532. [PMID: 38451953 PMCID: PMC10919644 DOI: 10.1371/journal.pone.0299532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/13/2024] [Indexed: 03/09/2024] Open
Abstract
Radon springs, characterized by their high concentrations of radon gas (Rn222), are extreme environments with unique physicochemical conditions distinct from conventional aquatic ecosystems. Our research aimed to investigate microbial life in radon springs, focusing on isolating extremophilic bacteria and assessing their resistance to adverse conditions. Our study revealed the prevalence of Actinomycetia species in the radon spring environment. We conducted various tests to evaluate the resistance of these isolates to oxidative stress, irradiation, desiccation, and metal ion content. These extremophilic bacteria showed overall higher resistance to these stresses compared to control strains. Lipidomic analysis was also employed to provide insights into the adaptive mechanisms of these bacteria which were found mainly in the correlations among individual clusters and changes in content of fatty acids (FA) as well as differences between content and type of FAs of environmental isolates and type strains.
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Affiliation(s)
- Elizaveta Timkina
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Marketa Kulišová
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Andrea Palyzová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Helena Marešová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Olga Maťátková
- Department of Biotechnology, University of Chemistry and Technology, Prague, Czech Republic
| | - Tomáš Řezanka
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
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4
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Granados-Tristán AL, Hernández-Luna CE, González-Escalante LA, Camacho-Moll ME, Silva-Ramírez B, Bermúdez de León M, Peñuelas-Urquides K. ESX-3 secretion system in Mycobacterium: An overview. Biochimie 2024; 216:46-55. [PMID: 37879428 DOI: 10.1016/j.biochi.2023.10.013] [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: 04/17/2023] [Revised: 09/26/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
Mycobacteria are microorganisms distributed in the environment worldwide, and some of them, such as Mycobacterium tuberculosis or M. leprae, are pathogenic. The hydrophobic mycobacterial cell envelope has low permeation and bacteria need to export products across their structure. Mycobacteria possess specialized protein secretion systems, such as the Early Secretory Antigenic Target 6 secretion (ESX) system. Five ESX loci have been described in M. tuberculosis, called ESX-1 to ESX-5. The ESX-3 secretion system has been associated with mycobacterial metabolism and growth. The locus of this system is highly conserved across mycobacterial species. Metallo-proteins regulate negative ESX-3 transcription in high conditions of iron and zinc. Moreover, this secretion system is part of an antioxidant regulatory pathway linked to Zinc. EccA3, EccB3, EccC3, EccD3, and EccE3 are components of the ESX-3 secretion machinery, whereas EsxG-EsxH, PE5-PPE4, and PE15-PPE20 are proteins secreted by this system. In addition, EspG3 and MycP3 are complementary proteins involved in transport and proteolysis respectively. This system is associated to mycobacterial virulence by releasing the bacteria from the phagosome and inhibiting endomembrane damage response. Furthermore, components of this system inhibit the host immune response by reducing the recognition of M. tuberculosis-infected cells. The components of the ESX-3 secretion system play a role in drug resistance and cell wall integrity. Moreover, the expression data of this system indicated that external and internal factors affect ESX-3 locus expression. This review provides an overview of new findings on the ESX-3 secretion system, its regulation, expression, and functions.
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Affiliation(s)
- Ana Laura Granados-Tristán
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico; Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, San Nicolás de los Garza, 66455, Nuevo León, Mexico.
| | - Carlos Eduardo Hernández-Luna
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, San Nicolás de los Garza, 66455, Nuevo León, Mexico.
| | - Laura Adiene González-Escalante
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - María Elena Camacho-Moll
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - Beatriz Silva-Ramírez
- Departamento de Inmunogenética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - Mario Bermúdez de León
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - Katia Peñuelas-Urquides
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
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Mahoney BJ, Goring AK, Wang Y, Dasika P, Zhou A, Grossbard E, Cascio D, Loo JA, Clubb RT. Development and atomic structure of a new fluorescence-based sensor to probe heme transfer in bacterial pathogens. J Inorg Biochem 2023; 249:112368. [PMID: 37729854 DOI: 10.1016/j.jinorgbio.2023.112368] [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: 04/30/2023] [Revised: 08/11/2023] [Accepted: 09/07/2023] [Indexed: 09/22/2023]
Abstract
Heme is the most abundant source of iron in the human body and is actively scavenged by bacterial pathogens during infections. Corynebacterium diphtheriae and other species of actinobacteria scavenge heme using cell wall associated and secreted proteins that contain Conserved Region (CR) domains. Here we report the development of a fluorescent sensor to measure heme transfer from the C-terminal CR domain within the HtaA protein (CR2) to other hemoproteins within the heme-uptake system. The sensor contains the CR2 domain inserted into the β2 to β3 turn of the Enhanced Green Fluorescent Protein (EGFP). A 2.45 Å crystal structure reveals the basis of heme binding to the CR2 domain via iron-tyrosyl coordination and shares conserved structural features with CR domains present in Corynebacterium glutamicum. The structure and small angle X-ray scattering experiments are consistent with the sensor adopting a V-shaped structure that exhibits only small fluctuations in inter-domain positioning. We demonstrate heme transfer from the sensor to the CR domains located within the HtaA or HtaB proteins in the heme-uptake system as measured by a ∼ 60% increase in sensor fluorescence and native mass spectrometry.
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Affiliation(s)
- Brendan J Mahoney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Andrew K Goring
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Yueying Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Poojita Dasika
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Anqi Zhou
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Emmitt Grossbard
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Duilio Cascio
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA.
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6
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Rahlwes KC, Dias BR, Campos PC, Alvarez-Arguedas S, Shiloh MU. Pathogenicity and virulence of Mycobacterium tuberculosis. Virulence 2023; 14:2150449. [PMID: 36419223 PMCID: PMC9817126 DOI: 10.1080/21505594.2022.2150449] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, an infectious disease with one of the highest morbidity and mortality rates worldwide. Leveraging its highly evolved repertoire of non-protein and protein virulence factors, Mtb invades through the airway, subverts host immunity, establishes its survival niche, and ultimately escapes in the setting of active disease to initiate another round of infection in a naive host. In this review, we will provide a concise synopsis of the infectious life cycle of Mtb and its clinical and epidemiologic significance. We will also take stock of its virulence factors and pathogenic mechanisms that modulate host immunity and facilitate its spread. Developing a greater understanding of the interface between Mtb virulence factors and host defences will enable progress toward improved vaccines and therapeutics to prevent and treat tuberculosis.
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Affiliation(s)
- Kathryn C. Rahlwes
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Beatriz R.S. Dias
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Priscila C. Campos
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Samuel Alvarez-Arguedas
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michael U. Shiloh
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA,Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA,CONTACT Michael U. Shiloh
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7
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Li B, Liao Y, Su X, Chen S, Wang X, Shen B, Song H, Yue P. Powering mesoporous silica nanoparticles into bioactive nanoplatforms for antibacterial therapies: strategies and challenges. J Nanobiotechnology 2023; 21:325. [PMID: 37684605 PMCID: PMC10485977 DOI: 10.1186/s12951-023-02093-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023] Open
Abstract
Bacterial infection has been a major threat to worldwide human health, in particular with the ever-increasing level of antimicrobial resistance. Given the complex microenvironment of bacterial infections, conventional use of antibiotics typically renders a low efficacy in infection control, thus calling for novel strategies for effective antibacterial therapies. As an excellent candidate for antibiotics delivery, mesoporous silica nanoparticles (MSNs) demonstrate unique physicochemical advantages in antibacterial therapies. Beyond the delivery capability, extensive efforts have been devoted in engineering MSNs to be bioactive to further synergize the therapeutic effect in infection control. In this review, we critically reviewed the essential properties of MSNs that benefit their antibacterial application, followed by a themed summary of strategies in manipulating MSNs into bioactive nanoplatforms for enhanced antibacterial therapies. The chemically functionalized platform, photo-synergized platform, physical antibacterial platform and targeting-directed platform are introduced in details, where the clinical translation challenges of these MSNs-based antibacterial nanoplatforms are briefly discussed afterwards. This review provides critical information of the emerging trend in turning bioinert MSNs into bioactive antibacterial agents, paving the way to inspire and translate novel MSNs-based nanotherapies in combating bacterial infection diseases.
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Affiliation(s)
- Biao Li
- Lab of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, 1688 MEILING Avenue, Nanchang, 330004, China
| | - Yan Liao
- Lab of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, 1688 MEILING Avenue, Nanchang, 330004, China
| | - Xiaoyu Su
- Lab of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, 1688 MEILING Avenue, Nanchang, 330004, China
| | - Shuiyan Chen
- Lab of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, 1688 MEILING Avenue, Nanchang, 330004, China
| | - Xinmin Wang
- Lab of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, 1688 MEILING Avenue, Nanchang, 330004, China
| | - Baode Shen
- Lab of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, 1688 MEILING Avenue, Nanchang, 330004, China
| | - Hao Song
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Pengfei Yue
- Lab of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, 1688 MEILING Avenue, Nanchang, 330004, China.
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8
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Harnagel AP, Sheshova M, Zheng M, Zheng M, Skorupinska-Tudek K, Swiezewska E, Lupoli TJ. Preference of Bacterial Rhamnosyltransferases for 6-Deoxysugars Reveals a Strategy To Deplete O-Antigens. J Am Chem Soc 2023. [PMID: 37437030 PMCID: PMC10375533 DOI: 10.1021/jacs.3c03005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Bacteria synthesize hundreds of bacteria-specific or "rare" sugars that are absent in mammalian cells and enriched in 6-deoxy monosaccharides such as l-rhamnose (l-Rha). Across bacteria, l-Rha is incorporated into glycans by rhamnosyltransferases (RTs) that couple nucleotide sugar substrates (donors) to target biomolecules (acceptors). Since l-Rha is required for the biosynthesis of bacterial glycans involved in survival or host infection, RTs represent potential antibiotic or antivirulence targets. However, purified RTs and their unique bacterial sugar substrates have been difficult to obtain. Here, we use synthetic nucleotide rare sugar and glycolipid analogs to examine substrate recognition by three RTs that produce cell envelope components in diverse species, including a known pathogen. We find that bacterial RTs prefer pyrimidine nucleotide-linked 6-deoxysugars, not those containing a C6-hydroxyl, as donors. While glycolipid acceptors must contain a lipid, isoprenoid chain length, and stereochemistry can vary. Based on these observations, we demonstrate that a 6-deoxysugar transition state analog inhibits an RT in vitro and reduces levels of RT-dependent O-antigen polysaccharides in Gram-negative cells. As O-antigens are virulence factors, bacteria-specific sugar transferase inhibition represents a novel strategy to prevent bacterial infections.
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Affiliation(s)
- Alexa P Harnagel
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Mia Sheshova
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Meng Zheng
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Maggie Zheng
- Department of Chemistry, New York University, New York, New York 10003, United States
| | | | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02-106, Poland
| | - Tania J Lupoli
- Department of Chemistry, New York University, New York, New York 10003, United States
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9
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Kumari S, Das S. Bacterial enzymatic degradation of recalcitrant organic pollutants: catabolic pathways and genetic regulations. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:79676-79705. [PMID: 37330441 DOI: 10.1007/s11356-023-28130-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 06/01/2023] [Indexed: 06/19/2023]
Abstract
Contamination of soil and natural water bodies driven by increased organic pollutants remains a universal concern. Naturally, organic pollutants contain carcinogenic and toxic properties threatening all known life forms. The conventional physical and chemical methods employed to remove these organic pollutants ironically produce toxic and non-ecofriendly end-products. Whereas microbial-based degradation of organic pollutants provides an edge, they are usually cost-effective and take an eco-friendly approach towards remediation. Bacterial species, including Pseudomonas, Comamonas, Burkholderia, and Xanthomonas, have the unique genetic makeup to metabolically degrade toxic pollutants, conferring their survival in toxic environments. Several catabolic genes, such as alkB, xylE, catA, and nahAc, that encode enzymes and allow bacteria to degrade organic pollutants have been identified, characterized, and even engineered for better efficacy. Aerobic and anaerobic processes are followed by bacteria to metabolize aliphatic saturated and unsaturated hydrocarbons such as alkanes, cycloalkanes, aldehydes, and ethers. Bacteria use a variety of degrading pathways, including catechol, protocatechuate, gentisate, benzoate, and biphenyl, to remove aromatic organic contaminants such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and pesticides from the environment. A better understanding of the principle, mechanisms, and genetics would be beneficial for improving the metabolic efficacy of bacteria to such ends. With a focus on comprehending the mechanisms involved in various catabolic pathways and the genetics of the biotransformation of these xenobiotic compounds, the present review offers insight into the various sources and types of known organic pollutants and their toxic effects on health and the environment.
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Affiliation(s)
- Swetambari Kumari
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Surajit Das
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India.
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10
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Wood PL, Erol E. Construction of a Bacterial Lipidomics Analytical Platform: Pilot Validation with Bovine Paratuberculosis Serum. Metabolites 2023; 13:809. [PMID: 37512516 PMCID: PMC10383236 DOI: 10.3390/metabo13070809] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
Lipidomics analyses of bacteria offer the potential to detect and monitor infections in a host since many bacterial lipids are not present in mammals. To evaluate this omics approach, we first built a database of bacterial lipids for representative Gram-positive and Gram-negative bacteria. Our lipidomics analysis of the reference bacteria involved high-resolution mass spectrometry and electrospray ionization with less than a 1.0 ppm mass error. The lipidomics profiles of bacterial cultures clearly distinguished between Gram-positive and Gram-negative bacteria. In the case of bovine paratuberculosis (PTB) serum, we monitored two unique bacterial lipids that we also monitored in Mycobacterium avian subspecies PTB. These were PDIM-B C82, a phthiodiolone dimycocerosate, and the trehalose monomycolate hTMM 28:1, constituents of the bacterial cell envelope in mycolic-containing bacteria. The next step will be to determine if lipidomics can detect subclinical PTB infections which can last 2-to-4 years in bovine PTB. Our data further suggest that it will be worthwhile to continue building our bacterial lipidomics database and investigate the further utility of this approach in other infections of veterinary and human clinical interest.
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Affiliation(s)
- Paul L Wood
- Metabolomics Unit, College of Veterinary Medicine, Lincoln Memorial University, 6965 Cumberland Gap Pkwy, Harrogate, TN 37752, USA
| | - Erdal Erol
- Department of Veterinary Science, Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, KY 40546, USA
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11
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Prithviraj M, Kado T, Mayfield JA, Young DC, Huang AD, Motooka D, Nakamura S, Siegrist MS, Moody DB, Morita YS. Tuberculostearic Acid Controls Mycobacterial Membrane Compartmentalization. mBio 2023; 14:e0339622. [PMID: 36976029 PMCID: PMC10127668 DOI: 10.1128/mbio.03396-22] [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: 12/05/2022] [Accepted: 03/08/2023] [Indexed: 03/29/2023] Open
Abstract
The intracellular membrane domain (IMD) is a laterally discrete region of the mycobacterial plasma membrane, enriched in the subpolar region of the rod-shaped cell. Here, we report genome-wide transposon sequencing to discover the controllers of membrane compartmentalization in Mycobacterium smegmatis. The putative gene cfa showed the most significant effect on recovery from membrane compartment disruption by dibucaine. Enzymatic analysis of Cfa and lipidomic analysis of a cfa deletion mutant (Δcfa) demonstrated that Cfa is an essential methyltransferase for the synthesis of major membrane phospholipids containing a C19:0 monomethyl-branched stearic acid, also known as tuberculostearic acid (TBSA). TBSA has been intensively studied due to its abundant and genus-specific production in mycobacteria, but its biosynthetic enzymes had remained elusive. Cfa catalyzed the S-adenosyl-l-methionine-dependent methyltransferase reaction using oleic acid-containing lipid as a substrate, and Δcfa accumulated C18:1 oleic acid, suggesting that Cfa commits oleic acid to TBSA biosynthesis, likely contributing directly to lateral membrane partitioning. Consistent with this model, Δcfa displayed delayed restoration of subpolar IMD and delayed outgrowth after bacteriostatic dibucaine treatment. These results reveal the physiological significance of TBSA in controlling lateral membrane partitioning in mycobacteria. IMPORTANCE As its common name implies, tuberculostearic acid is an abundant and genus-specific branched-chain fatty acid in mycobacterial membranes. This fatty acid, 10-methyl octadecanoic acid, has been an intense focus of research, particularly as a diagnostic marker for tuberculosis. It was discovered in 1934, and yet the enzymes that mediate the biosynthesis of this fatty acid and the functions of this unusual fatty acid in cells have remained elusive. Through a genome-wide transposon sequencing screen, enzyme assay, and global lipidomic analysis, we show that Cfa is the long-sought enzyme that is specifically involved in the first step of generating tuberculostearic acid. By characterizing a cfa deletion mutant, we further demonstrate that tuberculostearic acid actively regulates lateral membrane heterogeneity in mycobacteria. These findings indicate the role of branched fatty acids in controlling the functions of the plasma membrane, a critical barrier for the pathogen to survive in its human host.
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Affiliation(s)
- Malavika Prithviraj
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Takehiro Kado
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Jacob A. Mayfield
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - David C. Young
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Annie D. Huang
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Daisuke Motooka
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Shota Nakamura
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - M. Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
| | - D. Branch Moody
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
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Sparks IL, Nijjer J, Yan J, Morita YS. Lipoarabinomannan regulates septation in Mycobacterium smegmatis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.26.534150. [PMID: 36993273 PMCID: PMC10055410 DOI: 10.1101/2023.03.26.534150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The growth and division of mycobacteria, which include several clinically relevant pathogens, deviate significantly from that of canonical bacterial models. Despite their Gram-positive ancestry, mycobacteria synthesize and elongate a diderm envelope asymmetrically from the poles, with the old pole elongating more robustly than the new pole. In addition to being structurally distinct, the molecular components of the mycobacterial envelope are also evolutionarily unique, including the phosphatidylinositol-anchored lipoglycans lipomannan (LM) and lipoarabinomannan (LAM). LM and LAM modulate host immunity during infection, but their role outside of intracellular survival remains poorly understood, despite their widespread conservation among non-pathogenic and opportunistically pathogenic mycobacteria. Previously, Mycobacterium smegmatis and Mycobacterium tuberculosis mutants producing structurally altered LM and LAM were shown to grow slowly under certain conditions and to be more sensitive to antibiotics, suggesting that mycobacterial lipoglycans may support cellular integrity or growth. To test this, we constructed multiple biosynthetic lipoglycan mutants of M. smegmatis and determined the effect of each mutation on cell wall biosynthesis, envelope integrity, and division. We found that mutants deficient in LAM, but not LM, fail to maintain cell wall integrity in a medium-dependent manner, with envelope deformations specifically associated with septa and new poles. Conversely, a mutant producing abnormally large LAM formed multiseptated cells in way distinct from that observed in a septal hydrolase mutant. These results show that LAM plays critical and distinct roles at subcellular locations associated with division in mycobacteria, including maintenance of local cell envelope integrity and septal placement.
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Affiliation(s)
- Ian L. Sparks
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Japinder Nijjer
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Jing Yan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
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Mazumdar R, Dutta PP, Saikia J, Borah JC, Thakur D. Streptomyces sp. Strain PBR11, a Forest-Derived Soil Actinomycetia with Antimicrobial Potential. Microbiol Spectr 2023; 11:e0348922. [PMID: 36719230 PMCID: PMC10101066 DOI: 10.1128/spectrum.03489-22] [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: 08/31/2022] [Accepted: 12/21/2022] [Indexed: 02/01/2023] Open
Abstract
The Actinomycetia isolate PBR11 was isolated from the forest rhizosphere soil of Pobitora Wildlife Sanctuary (PWS), Assam, India. The isolate was identified as Streptomyces sp. with 92.91% sequence similarity to their closest type strain, Streptomyces atrovirens NRRL B-16357 DQ026672. The strain demonstrated significant antimicrobial activity against 19 test pathogens, including multidrug-resistant (MDR) clinical isolates and dermatophytes. Phenol, 2,5-bis(1,1-dimethylethyl), is the major chemical compound detected by gas chromatography-mass spectrometry in the ethyl acetate extract of PBR11 (EtAc-PBR11). The presence of the PKS type II gene (type II polyketide synthases) and chitinase gene suggested that it has been involved in the production of antimicrobial compounds. Metabolic profiling of the EtAc-PBR11 was performed by thin-layer chromatography and flash chromatography resulted in the extraction of two bioactive fractions, namely, PBR11Fr-1 and PBR11Fr-2. Liquid chromatography-tandem mass spectrometry analysis of both the fractions demonstrated the presence of significant antimicrobial compounds, including ethambutol. This is the first report on the detection of antituberculosis drug in the bioactive fractions of Streptomyces sp. PBR11. EtAc-PBR11 and PBR11Fr-1 showed the lowest MIC values (>0.097 and >0.048 μg/mL, respectively) against Candida albicans MTCC 227, whereas they showed the highest MIC values (>0.390 and >0.195 μg/mL, respectively) against Escherichia coli ATCC BAA-2469. The effects of PBR11Fr-1 were investigated on the pathogens by using a scanning electron microscope. The results indicated major morphological alterations in the cytoplasmic membrane. PBR11Fr-1 exhibited low cytotoxicity on normal hepatocyte cell line (CC-1) and the percent cell viability started to decline as the concentration increased from 50 μg/mL (87.07% ± 3.22%) to 100 μg/mL (81.26% ± 2.99%). IMPORTANCE Novel antibiotic breakthroughs are urgently required to combat antimicrobial resistance. Actinomycetia are the principal producers of antibiotics. The present study demonstrated the broad-spectrum antimicrobial potential of an Actinomycetia strain Streptomyces sp. strain PBR11 isolated from the PWS of Assam, India, which represents diverse, poorly screened habitats for novel microorganisms. The strain displayed 92.4% sequence similarity with genes of the closest type strain, indicating that the strain may represent a novel taxon within the phylum Actinomycetota. The metabolomics studies of EtAc-PBR11 revealed structurally diverse antimicrobial agents, including the detection of the antituberculosis drug ethambutol, in the bioactive fraction of Streptomyces sp. PBR11 for the first time. The PBR11 strain also yielded positive results for the antibiotic synthesis gene and the chitinase gene, both of which are responsible for broad-spectrum antimicrobial activity. This suggests that the untouched forest ecosystems have a tremendous potential to harbor potent actinomycetia for future drug discovery.
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Affiliation(s)
- Rajkumari Mazumdar
- Life Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, India
- Department of Molecular Biology and Biotechnology, Cotton University, Guwahati, India
| | | | - Juri Saikia
- Life Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, India
- Department of Biotechnology, Gauhati University, Guwahati, India
| | - Jagat Chandra Borah
- Life Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, India
| | - Debajit Thakur
- Life Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati, India
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Abstract
The genus Mycobacterium contains several slow-growing human pathogens, including Mycobacterium tuberculosis, Mycobacterium leprae, and Mycobacterium avium. Mycobacterium smegmatis is a nonpathogenic and fast growing species within this genus. In 1990, a mutant of M. smegmatis, designated mc2155, that could be transformed with episomal plasmids was isolated, elevating M. smegmatis to model status as the ideal surrogate for mycobacterial research. Classical bacterial models, such as Escherichia coli, were inadequate for mycobacteria research because they have low genetic conservation, different physiology, and lack the novel envelope structure that distinguishes the Mycobacterium genus. By contrast, M. smegmatis encodes thousands of conserved mycobacterial gene orthologs and has the same cell architecture and physiology. Dissection and characterization of conserved genes, structures, and processes in genetically tractable M. smegmatis mc2155 have since provided previously unattainable insights on these same features in its slow-growing relatives. Notably, tuberculosis (TB) drugs, including the first-line drugs isoniazid and ethambutol, are active against M. smegmatis, but not against E. coli, allowing the identification of their physiological targets. Furthermore, Bedaquiline, the first new TB drug in 40 years, was discovered through an M. smegmatis screen. M. smegmatis has become a model bacterium, not only for M. tuberculosis, but for all other Mycobacterium species and related genera. With a repertoire of bioinformatic and physical resources, including the recently established Mycobacterial Systems Resource, M. smegmatis will continue to accelerate mycobacterial research and advance the field of microbiology.
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Gu H, Hao X, Liu R, Shi Z, Zhao Z, Chen F, Wang W, Wang Y, Shen X. Small protein Cgl2215 enhances phenolic tolerance by promoting MytA activity in Corynebacterium glutamicum. STRESS BIOLOGY 2022; 2:49. [PMID: 37676548 PMCID: PMC10441969 DOI: 10.1007/s44154-022-00071-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 10/24/2022] [Indexed: 09/08/2023]
Abstract
Corynebacterium glutamicum is a promising chassis microorganism for the bioconversion of lignocellulosic biomass owing to its good tolerance and degradation of the inhibitors generated in lignocellulosic pretreatments. Among the identified proteins encoded by genes within the C. glutamicum genome, nearly 400 are still functionally unknown. Based on previous transcriptome analysis, we found that the hypothetical protein gene cgl2215 was highly upregulated in response to phenol, ferulic acid, and vanillin stress. The cgl2215 deletion mutant was shown to be more sensitive than the parental strain to phenolic compounds as well as other environmental factors such as heat, ethanol, and oxidative stresses. Cgl2215 interacts with C. glutamicum mycoloyltransferase A (MytA) and enhances its in vitro esterase activity. Sensitivity assays of the ΔmytA and Δcgl2215ΔmytA mutants in response to phenolic stress established that the role of Cgl2215 in phenolic tolerance was mediated by MytA. Furthermore, transmission electron microscopy (TEM) results showed that cgl2215 and mytA deletion both led to defects in the cell envelope structure of C. glutamicum, especially in the outer layer (OL) and electron-transparent layer (ETL). Collectively, these results indicate that Cgl2215 can enhance MytA activity and affect the cell envelope structure by directly interacting with MytA, thus playing an important role in resisting phenolic and other environmental stresses.
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Affiliation(s)
- Huawei Gu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Xinwei Hao
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Ruirui Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Zhenkun Shi
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Zehua Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Fu Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Wenqiang Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.
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The Roles of the Two-Component System, MtrAB, in Response to Diverse Cell Envelope Stresses in Dietzia sp. DQ12-45-1b. Appl Environ Microbiol 2022; 88:e0133722. [PMID: 36190258 PMCID: PMC9599347 DOI: 10.1128/aem.01337-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Two-component systems (TCSs) act as common regulatory systems allowing bacteria to detect and respond to multiple environmental stimuli, including cell envelope stress. The MtrAB TCS of Actinobacteria is critical for cell wall homeostasis, cell proliferation, osmoprotection, and antibiotic resistance, and thus is found to be highly conserved across this phylum. However, how precisely the MtrAB TCS regulates cellular homeostasis in response to environmental stress remains unclear. Here, we show that the MtrAB TCS plays an important role in the tolerance to different types of cell envelope stresses, including environmental stresses (i.e., oxidative stress, lysozyme, SDS, osmotic pressure, and alkaline pH stresses) and envelope-targeting antibiotics (i.e., isoniazid, ethambutol, glycopeptide, and β-lactam antibiotics) in Dietzia sp. DQ12-45-1b. An mtrAB mutant strain exhibited slower growth compared to the wild-type strain and was characterized by abnormal cell shapes when exposed to various environmental stresses. Moreover, deletion of mtrAB resulted in decreased resistance to isoniazid, ethambutol, and β-lactam antibiotics. Further, Cleavage under targets and tagmentation sequencing (CUT&Tag-seq) and electrophoretic mobility shift assays (EMSAs) revealed that MtrA binds the promoters of genes involved in peptidoglycan biosynthesis (ldtB, ldtA, murJ), hydrolysis (GJR88_03483, GJR88_4713), and cell division (ftsE). Together, our findings demonstrated that the MtrAB TCS is essential for the survival of Dietzia sp. DQ12-45-1b under various cell envelope stresses, primarily by controlling multiple downstream cellular pathways. Our work suggests that TCSs act as global sensors and regulators in maintaining cellular homeostasis, such as during episodes of various environmental stresses. The present study should shed light on the understanding of mechanisms for bacterial adaptivity to extreme environments. IMPORTANCE The multilayered cell envelope is the first line of bacterial defense against various extreme environments. Bacteria utilize a large number of sensing and regulatory systems to maintain cell envelope homeostasis under multiple stress conditions. The two-component system (TCS) is the main sensing and responding apparatus for environmental adaptation. The MtrAB TCS highly conserved in Actinobacteria is critical for cell wall homeostasis, cell proliferation, osmoprotection, and antibiotic resistance. However, how MtrAB works with regard to signals impacting changes to the cell envelope is not fully understood. Here, we found that in the Actinobacterium Dietzia sp. DQ12-45-1b, a TCS named MtrAB is pivotal for ensuring normal cell growth as well as maintaining proper cell morphology in response to various cell envelope stresses, namely, by regulating the expression of cell envelope-related genes. Our findings should greatly advance our understanding of the adaptive mechanisms responsible for maintaining cell integrity in times of sustained environmental shocks.
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Rudraraju RS, Daher SS, Gallardo-Macias R, Wang X, Neiditch MB, Freundlich JS. Mycobacterium tuberculosis KasA as a drug target: Structure-based inhibitor design. Front Cell Infect Microbiol 2022; 12:1008213. [PMID: 36189349 PMCID: PMC9519891 DOI: 10.3389/fcimb.2022.1008213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Recent studies have reported the β-ketoacyl-acyl carrier protein KasA as a druggable target for Mycobacterium tuberculosis. This review summarizes the current status of major classes of KasA inhibitors with an emphasis on significant contributions from structure-based design methods leveraging X-ray crystal structures of KasA alone and in complex with inhibitors. The issues addressed within each inhibitor class are discussed while detailing the characterized interactions with KasA and structure-activity relationships. A critical analysis of these findings should lay the foundation for new KasA inhibitors to study the basic biology of M. tuberculosis and to form the basis of new antitubercular molecules of clinical significance with activity against drug-sensitive and drug-resistant infections.
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Affiliation(s)
- Reshma S. Rudraraju
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Samer S. Daher
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Ricardo Gallardo-Macias
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Xin Wang
- Department of Immunology and Infectious Diseases, Harvard University T.H. Chan School of Public Health, Boston, MA, United States
| | - Matthew B. Neiditch
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, United States,*Correspondence: Matthew B. Neiditch, ; Joel S. Freundlich,
| | - Joel S. Freundlich
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, United States,Department of Medicine, Center for Emerging and Re-emerging Pathogens, New Jersey Medical School, Rutgers University, Newark, NJ, United States,*Correspondence: Matthew B. Neiditch, ; Joel S. Freundlich,
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18
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Nguyen PP, Kado T, Prithviraj M, Siegrist MS, Morita YS. Inositol acylation of phosphatidylinositol mannosides: a rapid mass response to membrane fluidization in mycobacteria. J Lipid Res 2022; 63:100262. [PMID: 35952902 PMCID: PMC9490103 DOI: 10.1016/j.jlr.2022.100262] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
Mycobacteria share an unusually complex, multilayered cell envelope, which contributes to adaptation to changing environments. The plasma membrane is the deepest layer of the cell envelope and acts as the final permeability barrier against outside molecules. There is an obvious need to maintain the plasma membrane integrity, but the adaptive responses of the plasma membrane to stress exposure remain poorly understood. Using chemical treatment and heat stress to fluidize the membrane, we show here that phosphatidylinositol (PI)-anchored plasma membrane glycolipids known as PI mannosides (PIMs) are rapidly remodeled upon membrane fluidization in Mycobacterium smegmatis. Without membrane stress, PIMs are predominantly in a triacylated form: two acyl chains of the PI moiety plus one acyl chain modified at one of the mannose residues. Upon membrane fluidization, we determined the fourth fatty acid is added to the inositol moiety of PIMs, making them tetra-acylated variants. Additionally, we show that PIM inositol acylation is a rapid response independent of de novo protein synthesis, representing one of the fastest mass conversions of lipid molecules found in nature. Strikingly, we found that M. smegmatis is more resistant to the bactericidal effect of a cationic detergent after benzyl alcohol pre-exposure. We further demonstrate that fluidization-induced PIM inositol acylation is conserved in pathogens such as Mycobacterium tuberculosis and Mycobacterium abscessus. Our results demonstrate that mycobacteria possess a mechanism to sense plasma membrane fluidity change. We suggest that inositol acylation of PIMs is a novel membrane stress response that enables mycobacterial cells to resist membrane fluidization.
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Affiliation(s)
- Peter P Nguyen
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Takehiro Kado
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | | | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA; Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA; Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, USA.
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Shi N, Bai T, Wang X, Tang Y, Wang C, Zhao L. Toxicological effects of WS 2 nanomaterials on rice plants and associated soil microbes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 832:154987. [PMID: 35378175 DOI: 10.1016/j.scitotenv.2022.154987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/26/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
As an important member of transition-metal dichalcogenides family, tungsten disulfides nanomaterials (WS2 NMs) have a wide range of applications. To date, their environmental risks remain largely unknown. In this study, rice plants were grown in soil amended with different concentrations (0, 10, and 100 mg/kg) of WS2 NMs for 4 weeks. WS2 NMs at 100 mg/kg significantly increased MDA (malondialdehyde) content and decreased total antioxidant capacities of leaves, indicating the oxidative response induced by WS2 NMs. Meanwhile, WS2 NMs at 100 mg/kg significantly decreased root biomass compared to control, indicating the negative impacts of WS2 NMs on plant growth. While exposure to 100 mg/kg WS2 NMs significantly increased soil bioavailable Cu, Fe, Zn, and Olsen-P, and increased the content of Cu, Fe, Zn, and P in rice leaves. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis showed that W was taken up by rice roots and translocated into leaves. The impact of WS2 on soil microbial communities was evaluated by 16S rRNA gene sequencing. WS2 NMs at 100 mg/kg significantly decreased soil microbial diversity, as indicated by decreased Shannon index. In addition, 100 mg/kg WS2 shifted the soil microbial profile, the relative abundance of the phylum Acidobacteriota decreased, and Actinobacteriota increased. Taken together, the soil microbial community's diversity and composition have been altered upon exposure to 100 mg/kg WS2 NMs. The results of this study provide some basic information regarding the environmental behavior and phytotoxicity of WS2 NMs, which is valuable for safe use of WS2 NMs.
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Affiliation(s)
- Nibin Shi
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Tonghao Bai
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Xiaojie Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Yuqiong Tang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Chao Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Lijuan Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China.
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Wang X, Liu Y. Offense and Defense in Granulomatous Inflammation Disease. Front Cell Infect Microbiol 2022; 12:797749. [PMID: 35846773 PMCID: PMC9277142 DOI: 10.3389/fcimb.2022.797749] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/30/2022] [Indexed: 11/13/2022] Open
Abstract
Granulomatous inflammation (GI) diseases are a group of chronic inflammation disorders characterized by focal collections of multinucleated giant cells, epithelioid cells and macrophages, with or without necrosis. GI diseases are closely related to microbes, especially virulent intracellular bacterial infections are important factors in the progression of these diseases. They employ a range of strategies to survive the stresses imposed upon them and persist in host cells, becoming the initiator of the fighting. Microbe-host communication is essential to maintain functions of a healthy host, so defense capacity of hosts is another influence factor, which is thought to combine to determine the result of the fighting. With the development of gene research technology, many human genetic loci were identified to be involved in GI diseases susceptibility, providing more insights into and knowledge about GI diseases. The current review aims to provide an update on the most recent progress in the identification and characterization of bacteria in GI diseases in a variety of organ systems and clinical conditions, and examine the invasion and escape mechanisms of pathogens that have been demonstrated in previous studies, we also review the existing data on the predictive factors of the host, mainly on genetic findings. These strategies may improve our understanding of the mechanisms underlying GI diseases, and open new avenues for the study of the associated conditions in the future.
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Affiliation(s)
- Xinwen Wang
- Shaanxi Clinical Research Center for Oral Diseases, National Clinical Research Center for Oral Diseases, State Key Laboratory of Military Stomatology, Department of Oral Medicine, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Yuan Liu
- Shaanxi International Joint Research Center for Oral Diseases, State Key Laboratory of Military Stomatology, Department of Histology and Pathology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
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21
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Fluorescence Imaging-Based Discovery of Membrane Domain-Associated Proteins in Mycobacterium smegmatis. J Bacteriol 2021; 203:e0041921. [PMID: 34516286 DOI: 10.1128/jb.00419-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mycobacteria spatially organize their plasma membrane, and many enzymes involved in envelope biosynthesis associate with a membrane compartment termed the intracellular membrane domain (IMD). The IMD is concentrated in the polar regions of growing cells and becomes less polarized under nongrowing conditions. Because mycobacteria elongate from the poles, the observed polar localization of the IMD during growth likely supports the localized biosynthesis of envelope components. While we have identified more than 300 IMD-associated proteins by proteomic analyses, only a few of these have been verified by independent experimental methods. Furthermore, some IMD-associated proteins may have escaped proteomic identification and remain to be identified. Here, we visually screened an arrayed library of 523 Mycobacterium smegmatis strains, each producing a Dendra2-FLAG-tagged recombinant protein. We identified 29 fusion proteins that showed polar fluorescence patterns characteristic of IMD proteins. Twenty of these had previously been suggested to localize to the IMD based on proteomic data. Of the nine remaining IMD candidate proteins, three were confirmed by biochemical methods to be associated with the IMD. Taken together, this new colocalization strategy is effective in verifying the IMD association of proteins found by proteomic analyses while facilitating the discovery of additional IMD-associated proteins. IMPORTANCE The intracellular membrane domain (IMD) is a membrane subcompartment found in Mycobacterium smegmatis cells. Proteomic analysis of purified IMD identified more than 300 proteins, including enzymes involved in cell envelope biosynthesis. However, proteomics on its own is unlikely to detect every IMD-associated protein because of technical and biological limitations. Here, we describe fluorescent protein colocalization as an alternative, independent approach. Using a combination of fluorescence microscopy, proteomics, and subcellular fractionation, we identified three new proteins associated with the IMD. Such a robust method to rigorously define IMD proteins will benefit future investigations to decipher the synthesis, maintenance, and functions of this membrane domain and help delineate a more general mechanism of subcellular protein localization in mycobacteria.
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Kaczmarczyk M, Löber U, Adamek K, Węgrzyn D, Skonieczna-Żydecka K, Malinowski D, Łoniewski I, Markó L, Ulas T, Forslund SK, Łoniewska B. The gut microbiota is associated with the small intestinal paracellular permeability and the development of the immune system in healthy children during the first two years of life. J Transl Med 2021; 19:177. [PMID: 33910577 PMCID: PMC8082808 DOI: 10.1186/s12967-021-02839-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 04/16/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The intestinal barrier plays an important role in the defense against infections, and nutritional, endocrine, and immune functions. The gut microbiota playing an important role in development of the gastrointestinal tract can impact intestinal permeability and immunity during early life, but data concerning this problem are scarce. METHODS We analyzed the microbiota in fecal samples (101 samples in total) collected longitudinally over 24 months from 21 newborns to investigate whether the markers of small intestinal paracellular permeability (zonulin) and immune system development (calprotectin) are linked to the gut microbiota. The results were validated using data from an independent cohort that included the calprotectin and gut microbiota in children during the first year of life. RESULTS Zonulin levels tended to increase for up to 6 months after childbirth and stabilize thereafter remaining at a high level while calprotectin concentration was high after childbirth and began to decline from 6 months of life. The gut microbiota composition and the related metabolic potentials changed during the first 2 years of life and were correlated with zonulin and calprotectin levels. Faecal calprotectin correlated inversely with alpha diversity (Shannon index, r = - 0.30, FDR P (Q) = 0.039). It also correlated with seven taxa; i.a. negatively with Ruminococcaceae (r = - 0.34, Q = 0.046), and Clostridiales (r = - 0.34, Q = 0.048) and positively with Staphylococcus (r = 0.38, Q = 0.023) and Staphylococcaceae (r = 0.35, Q = 0.04), whereas zonulin correlated with 19 taxa; i.a. with Bacillales (r = - 0.52, Q = 0.0004), Clostridiales (r = 0.48, Q = 0.001) and the Ruminococcus (torques group) (r = 0.40, Q = 0.026). When time intervals were considered only changes in abundance of the Ruminococcus (torques group) were associated with changes in calprotectin (β = 2.94, SE = 0.8, Q = 0.015). The dynamics of stool calprotectin was negatively associated with changes in two MetaCyc pathways: pyruvate fermentation to butanoate (β = - 4.54, SE = 1.08, Q = 0.028) and Clostridium acetobutylicum fermentation (β = - 4.48, SE = 1.16, Q = 0.026). CONCLUSIONS The small intestinal paracellular permeability, immune system-related markers and gut microbiota change dynamically during the first 2 years of life. The Ruminococcus (torques group) seems to be especially involved in controlling paracellular permeability. Staphylococcus, Staphylococcaceae, Ruminococcaceae, and Clostridiales, may be potential biomarkers of the immune system. Despite observed correlations their clear causation and health consequences were not proven. Mechanistic studies are required.
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Affiliation(s)
- Mariusz Kaczmarczyk
- Department of Clinical Biochemistry, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland
| | - Ulrike Löber
- Experimental and Clinical Research Center, A Cooperation of Charité - Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, 14195, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Karolina Adamek
- Department of Neonatal Diseases, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland
| | - Dagmara Węgrzyn
- Department of Neonatal Diseases, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland
| | | | - Damian Malinowski
- Department of Pharmacology, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland
| | - Igor Łoniewski
- Department of Biochemical Sciences, Pomeranian Medical University in Szczecin, 71-460, Szczecin, Poland.
- Department of Human Nutrition and Metabolomics, Broniewskiego 24, 71-460, Szczecin, Poland.
| | - Lajos Markó
- Experimental and Clinical Research Center, A Cooperation of Charité - Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, 14195, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), 10178, Berlin, Germany
| | - Thomas Ulas
- Systems Medicine, German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
- PRECISE Platform for Single Cell Genomics and Epigenomics at the German Center for Neurodegenerative Diseases and the University of Bonn, 53127, Bonn, Germany
| | - Sofia K Forslund
- Experimental and Clinical Research Center, A Cooperation of Charité - Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, 14195, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), 10178, Berlin, Germany
- Systems Medicine, German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117, Heidelberg, Germany
| | - Beata Łoniewska
- Department of Neonatal Diseases, Pomeranian Medical University in Szczecin, 70-111, Szczecin, Poland
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An ABC transporter Wzm-Wzt catalyzes translocation of lipid-linked galactan across the plasma membrane in mycobacteria. Proc Natl Acad Sci U S A 2021; 118:2023663118. [PMID: 33879617 DOI: 10.1073/pnas.2023663118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium tuberculosis, one of the deadliest pathogens in human history, is distinguished by a unique, multilayered cell wall, which offers the bacterium a high level of protection from the attacks of the host immune system. The primary structure of the cell wall core, composed of covalently linked peptidoglycan, branched heteropolysaccharide arabinogalactan, and mycolic acids, is well known, and numerous enzymes involved in the biosynthesis of its components are characterized. The cell wall biogenesis takes place at both cytoplasmic and periplasmic faces of the plasma membrane, and only recently some of the specific transport systems translocating the metabolic intermediates between these two compartments have been characterized [M. Jackson, C. M. Stevens, L. Zhang, H. I. Zgurskaya, M. Niederweis, Chem. Rev., 10.1021/acs.chemrev.0c00869 (2020)]. In this work, we use CRISPR interference methodology in Mycobacterium smegmatis to functionally characterize an ATP-binding cassette (ABC) transporter involved in the translocation of galactan precursors across the plasma membrane. We show that genetic knockdown of the transmembrane subunit of the transporter results in severe morphological changes and the accumulation of an aberrantly long galactan precursor. Based on similarities with structures and functions of specific O-antigen ABC transporters of gram-negative bacteria [C. Whitfield, D. M. Williams, S. D. Kelly, J. Biol. Chem. 295, 10593-10609 (2020)], we propose a model for coupled synthesis and export of the galactan polymer precursor in mycobacteria.
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Jose PA, Maharshi A, Jha B. Actinobacteria in natural products research: Progress and prospects. Microbiol Res 2021; 246:126708. [PMID: 33529791 DOI: 10.1016/j.micres.2021.126708] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/12/2021] [Accepted: 01/16/2021] [Indexed: 12/15/2022]
Abstract
Actinobacteria are well-recognised biosynthetic factories that produce an extensive spectrum of secondary metabolites. Recent genomic insights seem to impact the exploitation of these metabolically versatile bacteria in several aspects. Notably, from the isolation of novel taxa to the discovery of new compounds, different approaches evolve at a steady pace. Here, we systematically discuss the enduring importance of Actinobacteria in the field of drug discovery, the current focus of isolation efforts targeting bioactive Actinobacteria from diverse sources, recent discoveries of novel compounds with different bioactivities, and the relative employment of different strategies in the search for novel compounds. Ultimately, we highlight notable progress that will have profound impacts on future quests for secondary metabolites of Actinobacteria.
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Affiliation(s)
- Polpass Arul Jose
- Marine Biotechnology and Ecology Division, CSIR- Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar, Gujarat, 364002, India.
| | - Anjisha Maharshi
- Marine Biotechnology and Ecology Division, CSIR- Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar, Gujarat, 364002, India
| | - Bhavanath Jha
- Marine Biotechnology and Ecology Division, CSIR- Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar, Gujarat, 364002, India; Academy of Scientific and Innovative Research (AcSIR), CSIR, India.
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25
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Piazzon MC, Naya-Català F, Perera E, Palenzuela O, Sitjà-Bobadilla A, Pérez-Sánchez J. Genetic selection for growth drives differences in intestinal microbiota composition and parasite disease resistance in gilthead sea bream. MICROBIOME 2020; 8:168. [PMID: 33228779 PMCID: PMC7686744 DOI: 10.1186/s40168-020-00922-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/09/2020] [Indexed: 05/15/2023]
Abstract
BACKGROUND The key effects of intestinal microbiota in animal health have led to an increasing interest in manipulating these bacterial populations to improve animal welfare. The aquaculture sector is no exception and in the last years, many studies have described these populations in different fish species. However, this is not an easy task, as intestinal microbiota is composed of very dynamic populations that are influenced by different factors, such as diet, environment, host age, and genetics. In the current study, we aimed to determine whether the genetic background of gilthead sea bream (Sparus aurata) influences the intestinal microbial composition, how these bacterial populations are modulated by dietary changes, and the effect of selection by growth on intestinal disease resistance. To that aim, three different groups of five families of gilthead sea bream that were selected during two generations for fast, intermediate, or slow growth (F3 generation) were kept together in the same open-flow tanks and fed a control or a well-balanced plant-based diet during 9 months. Six animals per family and dietary treatment were sacrificed and the adherent bacteria from the anterior intestinal portion were sequenced. In parallel, fish of the fast- and slow-growth groups were infected with the intestinal parasite Enteromyxum leei and the disease signs, prevalence, intensity, and parasite abundance were evaluated. RESULTS No differences were detected in alpha diversity indexes among families, and the core bacterial architecture was the prototypical composition of gilthead sea bream intestinal microbiota, indicating no dysbiosis in any of the groups. The plant-based diet significantly changed the microbiota in the intermediate- and slow-growth families, with a much lower effect on the fast-growth group. Interestingly, the smaller changes detected in the fast-growth families potentially accounted for more changes at the metabolic level when compared with the other families. Upon parasitic infection, the fast-growth group showed significantly lower disease signs and parasite intensity and abundance than the slow-growth animals. CONCLUSIONS These results show a clear genome-metagenome interaction indicating that the fast-growth families harbor a microbiota that is more flexible upon dietary changes. These animals also showed a better ability to cope with intestinal infections. Video Abstract.
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Affiliation(s)
- M. Carla Piazzon
- Fish Pathology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain
| | - Fernando Naya-Català
- Nutrigenomics and Fish Endocrinology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain
| | - Erick Perera
- Fish Pathology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain
- Nutrigenomics and Fish Endocrinology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain
| | - Oswaldo Palenzuela
- Fish Pathology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain
| | - Ariadna Sitjà-Bobadilla
- Fish Pathology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain
| | - Jaume Pérez-Sánchez
- Nutrigenomics and Fish Endocrinology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain
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Role of LmeA, a Mycobacterial Periplasmic Protein, in Maintaining the Mannosyltransferase MptA and Its Product Lipomannan under Stress. mSphere 2020; 5:5/6/e01039-20. [PMID: 33148829 PMCID: PMC7643837 DOI: 10.1128/msphere.01039-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mycobacteria differentially regulate the cellular amounts of lipoglycans in response to environmental changes, but the molecular mechanisms of this regulation remain unknown. Here, we demonstrate that cellular lipoarabinomannan (LAM) levels rapidly decline under two stress conditions, stationary growth phase and nutrient starvation, while the levels of another related lipoglycan, lipomannan (LM), stay relatively constant. The persistence of LM under stress correlated with the maintenance of two key mannosyltransferases, MptA and MptC, in the LM biosynthetic pathway. We further showed that the stress exposures lead to the upregulation of lmeA gene expression and that the periplasmic protein LmeA plays a key role in maintaining the enzyme MptA and its product LM under stress conditions. These findings reveal new aspects of how lipoglycan biosynthesis is regulated under stress conditions in mycobacteria. The mycobacterial cell envelope has a diderm structure, composed of an outer mycomembrane, an arabinogalactan-peptidoglycan cell wall, a periplasm, and an inner membrane. Lipomannan (LM) and lipoarabinomannan (LAM) are structural and immunomodulatory components of this cell envelope. LM/LAM biosynthesis involves a number of mannosyltransferases and acyltransferases, and MptA is an α1,6-mannosyltransferase involved in the final extension of the mannan chain. Recently, we reported the periplasmic protein LmeA being involved in the maturation of the mannan backbone in Mycobacterium smegmatis. Here, we examined the role of LmeA under stress conditions. We found that lmeA transcription was upregulated under two stress conditions: stationary growth phase and nutrient starvation. Under both conditions, LAM was decreased, but LM was relatively stable, suggesting that maintaining the cellular level of LM under stress is important. Surprisingly, the protein levels of MptA were decreased in an lmeA deletion (ΔlmeA) mutant under both stress conditions. The transcript levels of mptA in the ΔlmeA mutant were similar to or even higher than those in the wild type, indicating that the decrease of MptA protein was a posttranscriptional event. The ΔlmeA mutant was unable to maintain the cellular level of LM under stress, consistent with the decrease in MptA. Even during active growth, overexpression of LmeA led the cells to produce more LM and become more resistant to several antibiotics. Altogether, our study reveals the roles of LmeA in the homeostasis of the MptA mannosyltransferase, particularly under stress conditions, ensuring the stable expression of LM and the maintenance of cell envelope integrity. IMPORTANCE Mycobacteria differentially regulate the cellular amounts of lipoglycans in response to environmental changes, but the molecular mechanisms of this regulation remain unknown. Here, we demonstrate that cellular lipoarabinomannan (LAM) levels rapidly decline under two stress conditions, stationary growth phase and nutrient starvation, while the levels of another related lipoglycan, lipomannan (LM), stay relatively constant. The persistence of LM under stress correlated with the maintenance of two key mannosyltransferases, MptA and MptC, in the LM biosynthetic pathway. We further showed that the stress exposures lead to the upregulation of lmeA gene expression and that the periplasmic protein LmeA plays a key role in maintaining the enzyme MptA and its product LM under stress conditions. These findings reveal new aspects of how lipoglycan biosynthesis is regulated under stress conditions in mycobacteria.
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27
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Tan YZ, Zhang L, Rodrigues J, Zheng RB, Giacometti SI, Rosário AL, Kloss B, Dandey VP, Wei H, Brunton R, Raczkowski AM, Athayde D, Catalão MJ, Pimentel M, Clarke OB, Lowary TL, Archer M, Niederweis M, Potter CS, Carragher B, Mancia F. Cryo-EM Structures and Regulation of Arabinofuranosyltransferase AftD from Mycobacteria. Mol Cell 2020; 78:683-699.e11. [PMID: 32386575 PMCID: PMC7263364 DOI: 10.1016/j.molcel.2020.04.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/21/2020] [Accepted: 04/13/2020] [Indexed: 01/21/2023]
Abstract
Mycobacterium tuberculosis causes tuberculosis, a disease that kills over 1 million people each year. Its cell envelope is a common antibiotic target and has a unique structure due, in part, to two lipidated polysaccharides-arabinogalactan and lipoarabinomannan. Arabinofuranosyltransferase D (AftD) is an essential enzyme involved in assembling these glycolipids. We present the 2.9-Å resolution structure of M. abscessus AftD, determined by single-particle cryo-electron microscopy. AftD has a conserved GT-C glycosyltransferase fold and three carbohydrate-binding modules. Glycan array analysis shows that AftD binds complex arabinose glycans. Additionally, AftD is non-covalently complexed with an acyl carrier protein (ACP). 3.4- and 3.5-Å structures of a mutant with impaired ACP binding reveal a conformational change, suggesting that ACP may regulate AftD function. Mutagenesis experiments using a conditional knockout constructed in M. smegmatis confirm the essentiality of the putative active site and the ACP binding for AftD function.
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Affiliation(s)
- Yong Zi Tan
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - José Rodrigues
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | | | - Sabrina I Giacometti
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Ana L Rosário
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Brian Kloss
- Center on Membrane Protein Production and Analysis, New York Structural Biology Center, New York, NY 10027, USA
| | - Venkata P Dandey
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Hui Wei
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Richard Brunton
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Ashleigh M Raczkowski
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Diogo Athayde
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Maria João Catalão
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Madalena Pimentel
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Department of Anesthesiology, Columbia University, New York, NY 10032, USA
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; Institute of Biological Chemistry, Academia Sinica, Academia Road, Section 2, #128 Nangang, Taipei 11529, Taiwan
| | - Margarida Archer
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Clinton S Potter
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Bridget Carragher
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
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