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Barbotin A, Billaudeau C, Sezgin E, Carballido-López R. Quantification of membrane fluidity in bacteria using TIR-FCS. Biophys J 2024; 123:2484-2495. [PMID: 38877702 PMCID: PMC11365102 DOI: 10.1016/j.bpj.2024.06.012] [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: 03/01/2024] [Revised: 05/28/2024] [Accepted: 06/10/2024] [Indexed: 06/16/2024] Open
Abstract
Plasma membrane fluidity is an important phenotypic feature that regulates the diffusion, function, and folding of transmembrane and membrane-associated proteins. In bacterial cells, variations in membrane fluidity are known to affect respiration, transport, and antibiotic resistance. Membrane fluidity must therefore be tightly regulated to adapt to environmental variations and stresses such as temperature fluctuations or osmotic shocks. Quantitative investigation of bacterial membrane fluidity has been, however, limited due to the lack of available tools, primarily due to the small size and membrane curvature of bacteria that preclude most conventional analysis methods used in eukaryotes. Here, we develop an assay based on total internal reflection-fluorescence correlation spectroscopy (TIR-FCS) to directly measure membrane fluidity in live bacteria via the diffusivity of fluorescent membrane markers. With simulations validated by experiments, we could determine how the small size, high curvature, and geometry of bacteria affect diffusion measurements and correct subsequent measurements for unbiased diffusion coefficient estimation. We used this assay to quantify the fluidity of the cytoplasmic membranes of the Gram-positive bacteria Bacillus subtilis (rod-shaped) and Staphylococcus aureus (coccus) at high (37°C) and low (20°C) temperatures in a steady state and in response to a cold shock, caused by a shift from high to low temperature. The steady-state fluidity was lower at 20°C than at 37°C, yet differed between B. subtilis and S. aureus at 37°C. Upon cold shock, the membrane fluidity decreased further below the steady-state fluidity at 20°C and recovered within 30 min in both bacterial species. Our minimally invasive assay opens up exciting perspectives for the study of a wide range of phenomena affecting the bacterial membrane, from disruption by chemicals or antibiotics to viral infection or change in nutrient availability.
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Affiliation(s)
- Aurélien Barbotin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.
| | - Cyrille Billaudeau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Rut Carballido-López
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.
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2
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Demey LM, Sinha R, DiRita VJ. An essential host dietary fatty acid promotes TcpH inhibition of TcpP proteolysis promoting virulence gene expression in Vibrio cholerae. mBio 2024; 15:e0072124. [PMID: 38958446 PMCID: PMC11323476 DOI: 10.1128/mbio.00721-24] [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: 04/11/2024] [Accepted: 05/03/2024] [Indexed: 07/04/2024] Open
Abstract
Vibrio cholerae is a Gram-negative gastrointestinal pathogen responsible for the diarrheal disease cholera. Expression of key virulence factors, cholera toxin and toxin-coregulated pilus, is regulated directly by ToxT and indirectly by two transmembrane transcription regulators (TTRs), ToxR and TcpP, that promote the expression of toxT. TcpP abundance and activity are controlled by TcpH, a single-pass transmembrane protein, which protects TcpP from a two-step proteolytic process known as regulated intramembrane proteolysis (RIP). The mechanism of TcpH-mediated protection of TcpP represents a major gap in our understanding of V. cholerae pathogenesis. The absence of tcpH leads to unimpeded degradation of TcpP in vitro and a colonization defect in a neonate mouse model of V. cholerae colonization. Here, we show that TcpH protects TcpP from RIP via direct interaction. We also demonstrate that α-linolenic acid, a dietary fatty acid, promotes TcpH-dependent inhibition of RIP via co-association of TcpP and TcpH molecules within detergent-resistant membranes (DRMs) in a mechanism requiring the TcpH transmembrane domain. Taken together, our data support a model where V. cholerae cells use exogenous α-linolenic acid to remodel the phospholipid bilayer in vivo, leading to co-association of TcpP and TcpH within DRMs where RIP of TcpP is inhibited by TcpH, thereby promoting V. cholerae pathogenicity. IMPORTANCE Vibrio cholerae continues to pose a significant global burden on health and an alternative therapeutic approach is needed, due to evolving multidrug resistance strains. Transcription of toxT, stimulated by TcpP and ToxR, is essential for V. cholerae pathogenesis. Our results show that TcpP, one of the major regulators of toxT gene expression, is protected from proteolysis by TcpH, via direct interaction. Furthermore, we identified a gut metabolite, α-linolenic acid, that stimulates the co-association of TcpP and TcpH within detergent-resistant membranes (also known as lipid-ordered membrane domains), thereby supporting TcpH-dependent antagonism of TcpP proteolysis. Data presented here extend our knowledge of RIP, virulence gene regulation in V. cholerae, and, to the best of our knowledge, provides the first evidence that lipid-ordered membranes exist within V. cholerae. The model presented here also suggests that TTRs, common among bacteria and archaea, and co-component signal transduction systems present in Enterobacteria, could also be influenced similarly.
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Affiliation(s)
- Lucas M. Demey
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Ritam Sinha
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Victor J. DiRita
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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3
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Dunn CM, Foust D, Gao Y, Biteen JS, Shaw SL, Kearns DB. Nascent flagellar basal bodies are immobilized by rod assembly in Bacillus subtilis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.02.606393. [PMID: 39211283 PMCID: PMC11360914 DOI: 10.1101/2024.08.02.606393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Flagella are complex, trans-envelope nanomachines that localize to species- specific cellular addresses. Here we study the localization dynamics of the earliest stage of basal body formation in Bacillus subtilis using a fluorescent fusion to the C-ring protein FliM. We find that B. subtilis basal bodies do not exhibit dynamic subunit exchange and are largely stationary at steady state, consistent with flagellar assembly through the peptidoglycan. Rare basal bodies were observed to be mobile however, and the frequency of basal body mobility is elevated both early in basal body assembly and when the rod is mutated. Thus, basal body mobility is a precursor to patterning and we propose that rod polymerization probes the peptidoglycan superstructure for pores of sufficient diameter that permit rod completion. Furthermore, mutation of the rod also disrupts basal body patterning in a way that phenocopies mutation of the cytoplasmic flagellar patterning protein FlhF. We infer that conformational changes in the basal body exchange information between rod synthesis and the cytoplasmic patterning proteins to restrict assembly at certain pores established by a grid-like pattern pre-existent in the peptidoglycan itself. IMPORTANCE Bacteria insert flagella in a species-specific pattern on the cell body, but how patterns are achieved is poorly understood. In bacteria with a single polar flagellum, a marker protein localizes to the cell pole and nucleates the assembly of the flagellum at that site. Bacillus subtilis assembles ∼15 flagella over the length of the cell body in a grid-like pattern and lacks all proteins associated with targeted assembly in polarly flagellated bacteria. Here we show that B. subtilis basal bodies are mobile soon after assembly and become immobilized when the flagellar rod transits the peptidoglycan wall. Moreover, defects in the flagellar rod lead to an asymmetric distribution of flagella with respect to the midcell. We conclude that the patterning of flagella is different in B. subtilis , and we infer that the B. subtilis rod probes the peptidoglycan for holes that can accommodate the machine.
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4
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Zhu Q, Wang S, Fu G, Guo F, Huang W, Zhang T, Dong H, Jin Z, Zhang D. Highly flexible cell membranes are the key to efficient production of lipophilic compounds. J Lipid Res 2024; 65:100597. [PMID: 39029799 PMCID: PMC11367113 DOI: 10.1016/j.jlr.2024.100597] [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: 03/30/2024] [Revised: 07/08/2024] [Accepted: 07/10/2024] [Indexed: 07/21/2024] Open
Abstract
Lipophilic compounds have a variety of positive effects on human physiological functions and exhibit good effects in the prevention and treatment of clinical diseases. This has led to significant interest in the technical applications of synthetic biology for the production of lipophilic compounds. However, the strict selective permeability of the cell membrane and the hydrophobic nature of lipophilic compounds pose significant challenges to their production. During fermentation, lipophilic compounds tend to accumulate within cell membrane compartments rather than being secreted extracellularly. The toxic effects of excessive lipophilic compound accumulation can threaten cell viability, while the limited space within the cell membrane restricts further increases in production yield. Consequently, to achieve efficient production of lipophilic compounds, research is increasingly focused on constructing robust and multifunctional microbial cell factories. Utilizing membrane engineering techniques to construct highly flexible cell membranes is considered an effective strategy to break through the upper limit of lipophilic compound production. Currently, there are two main approaches to cell membrane modification: constructing artificial storage compartments for lipophilic compounds and engineering the cell membrane structure to facilitate product outflow. This review summarizes recent cell membrane engineering strategies applied in microbial cell factories for the production of liposoluble compounds, discussing the challenges and future prospects. These strategies enhance membrane flexibility and effectively promote the production of liposoluble compounds.
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Affiliation(s)
- Qiyao Zhu
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China; Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Sijia Wang
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China; Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Gang Fu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, China.
| | - Fengming Guo
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Wei Huang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Tengyue Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Huina Dong
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, China
| | - Zhaoxia Jin
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China.
| | - Dawei Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, China.
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5
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Fu Q, Qiu Y, Zhao J, Li J, Xie S, Liao Q, Fu X, Huang Y, Yao Z, Dai Z, Qiu Y, Yang Y, Li F, Chen H. Monotonic trends of soil microbiomes, metagenomic and metabolomic functioning across ecosystems along water gradients in the Altai region, northwestern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169351. [PMID: 38123079 DOI: 10.1016/j.scitotenv.2023.169351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/21/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
To investigate microbial communities and their contributions to carbon and nutrient cycling along water gradients can enhance our comprehension of climate change impacts on ecosystem services. Thus, we conducted an assessment of microbial communities, metagenomic functions, and metabolomic profiles within four ecosystems, i.e., desert grassland (DG), shrub-steppe (SS), forest (FO), and marsh (MA) in the Altai region of Xinjiang, China. Our results showed that soil total carbon (TC), total nitrogen, NH4+, and NO3- increased, but pH decreased with soil water gradients. Microbial abundances and richness also increased with soil moisture except the abundances of fungi and protists being lowest in MA. A shift in microbial community composition is evident along the soil moisture gradient, with Proteobacteria, Basidiomycota, and Evosea proliferating but a decline in Actinobacteria and Cercozoa. The β-diversity of microbiomes, metagenomic, and metabolomic functioning were correlated with soil moisture gradients and have significant associations with specific soil factors of TC, NH4+, and pH. Metagenomic functions associated with carbohydrate and DNA metabolisms, as well as phages, prophages, TE, plasmids functions diminished with moisture, whereas the genes involved in nitrogen and potassium metabolism, along with certain biological interactions and environmental information processing functions, demonstrated an augmentation. Additionally, MA harbored the most abundant metabolomics dominated by lipids and lipid-like molecules and organic oxygen compounds, except certain metabolites showing decline trends along water gradients, such as N'-Hydroxymethylnorcotinine and 5-Hydroxyenterolactone. Thus, our study suggests that future ecosystem succession facilitated by changes in rainfall patterns will significantly alter soil microbial taxa, functional potential, and metabolite fractions.
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Affiliation(s)
- Qi Fu
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Yingbo Qiu
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Jiayi Zhao
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Jiaxin Li
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Siqi Xie
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Qiuchang Liao
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Xianheng Fu
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Yu Huang
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Zhiyuan Yao
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Zhongmin Dai
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yunpeng Qiu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Yuchun Yang
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Furong Li
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China.
| | - Huaihai Chen
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-sen University Sun Yat-sen University, Shenzhen, Guangdong 518107, China.
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6
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Otrin N, Otrin L, Bednarz C, Träger TK, Hamdi F, Kastritis PL, Ivanov I, Sundmacher K. Protein-Rich Rafts in Hybrid Polymer/Lipid Giant Unilamellar Vesicles. Biomacromolecules 2024; 25:778-791. [PMID: 38190609 PMCID: PMC10865357 DOI: 10.1021/acs.biomac.3c00972] [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: 09/13/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/10/2024]
Abstract
Considerable attention has been dedicated to lipid rafts due to their importance in numerous cell functions such as membrane trafficking, polarization, and signaling. Next to studies in living cells, artificial micrometer-sized vesicles with a minimal set of components are established as a major tool to understand the phase separation dynamics and their intimate interplay with membrane proteins. In parallel, mixtures of phospholipids and certain amphiphilic polymers simultaneously offer an interface for proteins and mimic this segregation behavior, presenting a tangible synthetic alternative for fundamental studies and bottom-up design of cellular mimics. However, the simultaneous insertion of complex and sensitive membrane proteins is experimentally challenging and thus far has been largely limited to natural lipids. Here, we present the co-reconstitution of the proton pump bo3 oxidase and the proton consumer ATP synthase in hybrid polymer/lipid giant unilamellar vesicles (GUVs) via fusion/electroformation. Variations of the current method allow for tailored reconstitution protocols and control of the vesicle size. In particular, mixing of protein-free and protein-functionalized nanosized vesicles in the electroformation film results in larger GUVs, while separate reconstitution of the respiratory enzymes enables higher ATP synthesis rates. Furthermore, protein labeling provides a synthetic mechanism for phase separation and protein sequestration, mimicking lipid- and protein-mediated domain formation in nature. The latter means opens further possibilities for re-enacting phenomena like supercomplex assembly or symmetry breaking and enriches the toolbox of bottom-up synthetic biology.
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Affiliation(s)
- Nika Otrin
- Process
Systems Engineering, Max Planck Institute
for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Lado Otrin
- Process
Systems Engineering, Max Planck Institute
for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Claudia Bednarz
- Process
Systems Engineering, Max Planck Institute
for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Toni K. Träger
- Interdisciplinary
Research Center HALOmem and Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Biozentrum, 06120 Halle/Saale, Germany
| | - Farzad Hamdi
- Interdisciplinary
Research Center HALOmem and Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Biozentrum, 06120 Halle/Saale, Germany
| | - Panagiotis L. Kastritis
- Interdisciplinary
Research Center HALOmem and Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Biozentrum, 06120 Halle/Saale, Germany
- Institute
of Chemical Biology, National Hellenic Research
Foundation, 11635 Athens, Greece
| | - Ivan Ivanov
- Process
Systems Engineering, Max Planck Institute
for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
- Grup
de Biotecnologia Molecular i Industrial, Department of Chemical Engineering, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, 08222 Terrassa, Spain
| | - Kai Sundmacher
- Process
Systems Engineering, Max Planck Institute
for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
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Bose S, Dahat Y, Kumar D, Haldar S, Das SK. A membrane targeted multifunctional cationic nanoparticle conjugated fusogenic nanoemulsion (CFusoN): induced membrane depolarization and lipid solubilization to accelerate the killing of Staphylococcus aureus. MATERIALS HORIZONS 2024; 11:661-679. [PMID: 37830433 DOI: 10.1039/d3mh01102j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Bacterial infections caused by Staphylococcus aureus are one of the growing concerns for human health care management globally. Antibiotic-associated adverse effects and the emergence of bacterial resistant strains necessitate the development of an alternative yet effective approach. Nanoemulsion-based therapy has emerged as a potential therapeutic strategy to combat bacterial infestation. Herein, we designed a cationic metal nanoparticle-conjugated fusogenic nanoemulsion (CFusoN) as a lipid solubilizing nanovesicle for the effective treatment of S. aureus infection with a killing efficiency of 99.999%. The cationic nanoparticle-conjugated nanoemulsion (viz. NECNP) (24.4 ± 2.9 mV) electrostatically bound with the negatively charged bacterial cell membrane (-10.2 ± 3.7 mV) causing alteration of the bacterial surface charge. The fluorometric and flow cytometry studies confirmed the bacterial membrane depolarization and altered cell membrane permeability leading to cell death. The atomic force microscopic studies further demonstrated the damage of the cellular ultrastructure, while the transmission electron microscopic image and membrane lipid solubilization analysis depicted the solubilization of the bacterial membrane lipid bilayer along with the leakage of the intracellular contents. The cell membrane fatty acid analysis revealed that the methyl esters of palmitic acid, stearic acid and octadecadienoic acid isomers were solubilized after the treatment of S. aureus with CFusoN. The bactericidal killing efficiency of CFusoN is proposed to occur through the synergistic efficacy of the targeted attachment of CNP to the bacterial cells along with the lipid solubilization property of NE. Interestingly, NECNP didn't elicit any in vitro hemolytic activity or cytotoxicity against red blood cells (RBCs) and L929 fibroblast cells, respectively, at its bactericidal concentration. Furthermore, a porcine skin wound infection model exhibited the enhanced wound cleansing potency of CFusoN in comparison to the commercially available wound cleansers. The obtained antibacterial activity, biocompatibility and skin wound disinfection efficacy of the NECNP demonstrated the formulation of a cell targeted CFusoN as a promising translatable strategy to combat bacterial infection.
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Affiliation(s)
- Somashree Bose
- Infectious Diseases and Immunology Division, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Yogita Dahat
- Organic and Medicinal Chemistry, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology (IICB), Kolkata-700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Deepak Kumar
- Organic and Medicinal Chemistry, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology (IICB), Kolkata-700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Saikat Haldar
- Agrotechnology and Rural Development Division (ARDD), CSIR-North East Institute of Science and Technology (NEIST), NH37, Pulibor, Jorhat, Assam 785006, India
| | - Sujoy K Das
- Infectious Diseases and Immunology Division, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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8
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Turbant F, Machiels Q, Waeytens J, Wien F, Arluison V. The Amyloid Assembly of the Bacterial Hfq Is Lipid-Driven and Lipid-Specific. Int J Mol Sci 2024; 25:1434. [PMID: 38338713 PMCID: PMC10855545 DOI: 10.3390/ijms25031434] [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: 12/27/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Under specific conditions, some proteins can self-assemble into fibrillar structures called amyloids. Initially, these proteins were associated with neurodegenerative diseases in eucaryotes. Nevertheless, they have now been identified in the three domains of life. In bacteria, they are involved in diverse biological processes and are usually useful for the cell. For this reason, they are classified as "functional amyloids". In this work, we focus our analysis on a bacterial functional amyloid called Hfq. Hfq is a pleiotropic regulator that mediates several aspects of genetic expression, mainly via the use of small noncoding RNAs. Our previous work showed that Hfq amyloid-fibrils interact with membranes. This interaction influences Hfq amyloid structure formation and stability, but the specifics of the lipid on the dynamics of this process is unknown. Here, we show, using spectroscopic methods, how lipids specifically drive and modulate Hfq amyloid assembly or, conversely, its disassembly. The reported effects are discussed in light of the consequences for bacterial cell life.
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Affiliation(s)
- Florian Turbant
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, CEA Saclay, 91191 Gif-sur-Yvette, France;
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France;
- Department of Molecular Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Quentin Machiels
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; (Q.M.); (J.W.)
| | - Jehan Waeytens
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; (Q.M.); (J.W.)
- Unit of Pharmacognosy, Bioanalysis and Drug Discovery, Université Libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Frank Wien
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France;
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, CEA Saclay, 91191 Gif-sur-Yvette, France;
- SDV Department, Université Paris Cité, 75006 Paris, France
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9
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Stolarek P, Bernat P, Różalski A. Adjustment in the Composition and Organization of Proteus mirabilis Lipids during the Swarming Process. Int J Mol Sci 2023; 24:16461. [PMID: 38003652 PMCID: PMC10671106 DOI: 10.3390/ijms242216461] [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: 10/16/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Proteus mirabilis, an opportunistic pathogen of the urinary tract, is known for its dimorphism and mobility. A connection of lipid alterations, induced by the rods elongation process, with enhanced pathogenicity of long-form morphotype for the development of urinary tract infections, seems highly probable. Therefore, research on the adjustment in the composition and organization of P. mirabilis lipids forming elongated rods was undertaken. The analyses performed using the ultra-high performance liquid chromatography with tandem mass spectrometry showed that drastic modifications in the morphology of P. mirabilis rods that occur during the swarming process are directly related to deprivation of the long-form cells of PE 33:1 and PG 31:2 and their enrichment with PE 32:1, PE 34:1, PE 34:2, PG 30:2, PG 32:1, and PG 34:1. The analyses conducted by the gas chromatography-mass spectrometry showed negligible effects of the swarming process on fatty acids synthesis. However, the constant proportions between unsaturated and saturated fatty acids confirmed that phenotypic modifications in the P. mirabilis rods induced by motility were independent of the saturation of the phospholipid tails. The method of the Förster resonance energy transfer revealed the influence of the swarming process on the melting of ordered lipid rafts present in the short-form rods, corresponding to the homogeneity of lipid bilayers in the long-form rods of P. mirabilis. Confocal microscope photographs visualized strong Rhod-PE fluorescence of the whole area of swarmer cells, in contrast to weak membrane fluorescence of non-swarmer cells. It suggested an increased permeability of the P. mirabilis bilayers in long-form rods morphologically adapted to the swarming process. These studies clearly demonstrate that swarming motility regulates the lipid composition and organization in P. mirabilis rods.
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Affiliation(s)
- Paulina Stolarek
- Department of Biology of Bacteria, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland;
| | - Przemysław Bernat
- Department of Industrial Microbiology and Biotechnology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland;
| | - Antoni Różalski
- Department of Biology of Bacteria, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland;
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10
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Olivan-Muro I, Sarasa-Buisan C, Guio J, Arenas J, Sevilla E, Fillat MF. Unbalancing Zur (FurB)-mediated homeostasis in Anabaena sp. PCC7120: Consequences on metal trafficking, heterocyst development and biofilm formation. Environ Microbiol 2023; 25:2142-2162. [PMID: 37315963 DOI: 10.1111/1462-2920.16434] [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: 01/17/2023] [Accepted: 05/22/2023] [Indexed: 06/16/2023]
Abstract
Zinc is required for the activity of many enzymes and plays an essential role in gene regulation and redox homeostasis. In Anabaena (Nostoc) sp. PCC7120, the genes involved in zinc uptake and transport are controlled by the metalloregulator Zur (FurB). Comparative transcriptomics of a zur mutant (Δzur) with the parent strain unveiled unexpected links between zinc homeostasis and other metabolic pathways. A notable increase in the transcription of numerous desiccation tolerance-related genes, including genes involved in the synthesis of trehalose and the transference of saccharide moieties, among many others, was detected. Biofilm formation analysis under static conditions revealed a reduced capacity of Δzur filaments to form biofilms compared to the parent strain, and such capacity was enhanced when Zur was overexpressed. Furthermore, microscopy analysis revealed that zur expression is required for the correct formation of the envelope polysaccharide layer in the heterocyst, as Δzur cells showed reduced staining with alcian blue compared to Anabaena sp. PCC7120. We suggest that Zur is an important regulator of the enzymes involved in the synthesis and transport of the envelope polysaccharide layer, influencing heterocyst development and biofilm formation, both relevant processes for cell division and interaction with substrates in its ecological niche.
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Affiliation(s)
- Irene Olivan-Muro
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Cristina Sarasa-Buisan
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Jorge Guio
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Jesús Arenas
- Department of Animal Pathology, Unit of Microbiology and Immunology, Faculty of Veterinary, University of Zaragoza, Zaragoza, Spain
| | - Emma Sevilla
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Maria F Fillat
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Bioinformatics and Physical of Complex Systems, University of Zaragoza, Zaragoza, Spain
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11
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Zamora-Prieto RM, Maldonado-Serrano JF, González-Calderón W. The life of the cell membrane: A paradigmatic reading from Deleuze and Guattari. Heliyon 2023; 9:e21924. [PMID: 38045203 PMCID: PMC10692771 DOI: 10.1016/j.heliyon.2023.e21924] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 09/12/2023] [Accepted: 10/31/2023] [Indexed: 12/05/2023] Open
Abstract
While the Fluid Mosaic model (FMM) is widely accepted as an account of the cell membrane's structure-function, its inability to explain certain phenomena has led to the lipid rafts hypothesis (nanodomains) that spontaneous spatiotemporal enriched zones of sphingolipids-cholesterol-protein exist within the membrane. In this text, we propose a novel approach that conceives the cell membrane as a living entity. The questions regarding the FMM revolve around the fact that, although these molecular components are present in many cell types, the membrane does not react in the same way to every external agent; for example, a virus evokes a particular response: why is there some marked specificity of virus (or toxin) attack on one (or some) of these cell types and not to other cell types that nevertheless have a similar membrane protein constitution? The crucial question, to explain this selectivity, would be what determines the specificity of attack on some cells and not others? While FMN assumes a dynamism between macrostates at the intramolecular, intermolecular, and/or collective levels in the membrane, the approach of the lipid raft model presupposes a much greater and more complex dynamics of microstates (even nano-states) of these molecular components. In other words, it implies higher and instantaneous mobility as assemblages ("intentional") and thus, of the membrane itself (as a collective), in response to changes in the internal and external physicochemical environment over a broad spatiotemporal scale. This suggests a mechanism of membrane adaptation in the face of evolutionary constraints. In this text, we propose a paradigmatic approach, from Deleuze-Guattari's philosophy: to conceive the cell membrane as living and not as a mere molecular conglomerate with particular functions and mechanical processes between molecules. For this, we employ the functional concepts of territory and machinic assemblage, whence the vitality of the membrane would allow us to postulate instantaneous updates, within wider spatiotemporal scales in its composition in contrast with the model that dominates as a more plausible explanation nowadays, that does not include smaller spatiotemporal events. If we resort to the concept of territory and its different media components, we could offer a more plausible explanation of the vigorous dynamism in the composition of the cell membrane since it would allow more subtle and complex differentiations between media and thus make visible the constant and instant changes. We propose that the model of nanodomains, understood as a process of dynamic territorialization, offers a more complex and subtle explanation of the instantaneous changes in the cell membrane's composition. This approach expands the explanatory framework for cellular phenomena and reveals their spatiotemporal complexity in accordance with other research.
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Affiliation(s)
- Rafael Maria Zamora-Prieto
- Facultad de Ciencias de la Salud, Universidad Autónoma de Bucaramanga - UNAB, Bucaramanga, 681003, Colombia
| | | | - William González-Calderón
- Departamento de Ciencias Básicas, Universidad Autónoma de Bucaramanga - UNAB, Bucaramanga, 681003, Colombia
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12
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Bramkamp M, Scheffers DJ. Bacterial membrane dynamics: Compartmentalization and repair. Mol Microbiol 2023; 120:490-501. [PMID: 37243899 DOI: 10.1111/mmi.15077] [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: 03/31/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 05/29/2023]
Abstract
In every bacterial cell, the plasma membrane plays a key role in viability as it forms a selective barrier between the inside of the cell and its environment. This barrier function depends on the physical state of the lipid bilayer and the proteins embedded or associated with the bilayer. Over the past decade or so, it has become apparent that many membrane-organizing proteins and principles, which were described in eukaryote systems, are ubiquitous and play important roles in bacterial cells. In this minireview, we focus on the enigmatic roles of bacterial flotillins in membrane compartmentalization and bacterial dynamins and ESCRT-like systems in membrane repair and remodeling.
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Affiliation(s)
- Marc Bramkamp
- Institute for General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Dirk-Jan Scheffers
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
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13
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Dupuy P, Gutierrez C, Neyrolles O. Modulation of bacterial membrane proteins activity by clustering into plasma membrane nanodomains. Mol Microbiol 2023; 120:502-507. [PMID: 37303242 DOI: 10.1111/mmi.15105] [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: 02/27/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/13/2023]
Abstract
Recent research has demonstrated specific protein clustering within membrane subdomains in bacteria, challenging the long-held belief that prokaryotes lack these subdomains. This mini review provides examples of bacterial membrane protein clustering, discussing the benefits of protein assembly in membranes and highlighting how clustering regulates protein activity.
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Affiliation(s)
- Pierre Dupuy
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Claude Gutierrez
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Olivier Neyrolles
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
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14
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Wessel AK, Yoshii Y, Reder A, Boudjemaa R, Szczesna M, Betton JM, Bernal-Bayard J, Beloin C, Lopez D, Völker U, Ghigo JM. Escherichia coli SPFH Membrane Microdomain Proteins HflKC Contribute to Aminoglycoside and Oxidative Stress Tolerance. Microbiol Spectr 2023; 11:e0176723. [PMID: 37347165 PMCID: PMC10434171 DOI: 10.1128/spectrum.01767-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 06/01/2023] [Indexed: 06/23/2023] Open
Abstract
Many eukaryotic membrane-dependent functions are often spatially and temporally regulated by membrane microdomains (FMMs), also known as lipid rafts. These domains are enriched in polyisoprenoid lipids and scaffolding proteins belonging to the stomatin, prohibitin, flotillin, and HflK/C (SPFH) protein superfamily that was also identified in Gram-positive bacteria. In contrast, little is still known about FMMs in Gram-negative bacteria. In Escherichia coli K-12, 4 SPFH proteins, YqiK, QmcA, HflK, and HflC, were shown to localize in discrete polar or lateral inner membrane locations, raising the possibility that E. coli SPFH proteins could contribute to the assembly of inner membrane FMMs and the regulation of cellular processes. Here, we studied the determinant of the localization of QmcA and HflC and showed that FMM-associated cardiolipin lipid biosynthesis is required for their native localization pattern. Using Biolog phenotypic arrays, we showed that a mutant lacking all SPFH genes displayed increased sensitivity to aminoglycosides and oxidative stress that is due to the absence of HflKC. Our study therefore provides further insights into the contribution of SPFH proteins to stress tolerance in E. coli. IMPORTANCE Eukaryotic cells often segregate physiological processes in cholesterol-rich functional membrane microdomains. These domains are also called lipid rafts and contain proteins of the stomatin, prohibitin, flotillin, and HflK/C (SPFH) superfamily, which are also present in prokaryotes but have been mostly studied in Gram-positive bacteria. Here, we showed that the cell localization of the SPFH proteins QmcA and HflKC in the Gram-negative bacterium E. coli is altered in the absence of cardiolipin lipid synthesis. This suggests that cardiolipins contribute to E. coli membrane microdomain assembly. Using a broad phenotypic analysis, we also showed that HflKC contribute to E. coli tolerance to aminoglycosides and oxidative stress. Our study, therefore, provides new insights into the cellular processes associated with SPFH proteins in E. coli.
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Affiliation(s)
- Aimee K. Wessel
- Institut Pasteur, Université de Paris-Cité, CNRS UMR6047, Genetics of Biofilms Laboratory, Paris, France
| | - Yutaka Yoshii
- Institut Pasteur, Université de Paris-Cité, CNRS UMR6047, Genetics of Biofilms Laboratory, Paris, France
| | - Alexander Reder
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | | | - Magdalena Szczesna
- Institut Pasteur, Université de Paris-Cité, CNRS UMR6047, Genetics of Biofilms Laboratory, Paris, France
- Centre for Bacteriology Resistance Biology, Imperial College London, London, United Kingdom
| | - Jean-Michel Betton
- Institut Pasteur, Université de Paris-Cité, UMR UMR6047, Stress adaptation and metabolism in enterobacteria, Paris, France
| | - Joaquin Bernal-Bayard
- Institut Pasteur, Université de Paris-Cité, CNRS UMR6047, Genetics of Biofilms Laboratory, Paris, France
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Christophe Beloin
- Institut Pasteur, Université de Paris-Cité, CNRS UMR6047, Genetics of Biofilms Laboratory, Paris, France
| | - Daniel Lopez
- Universidad Autonoma de Madrid, Centro Nacional de Biotecnologia, Madrid, Spain
| | - Uwe Völker
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Jean-Marc Ghigo
- Institut Pasteur, Université de Paris-Cité, CNRS UMR6047, Genetics of Biofilms Laboratory, Paris, France
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15
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Mitchison-Field LM, Belin BJ. Bacterial lipid biophysics and membrane organization. Curr Opin Microbiol 2023; 74:102315. [PMID: 37058914 PMCID: PMC10523990 DOI: 10.1016/j.mib.2023.102315] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 04/16/2023]
Abstract
The formation of lateral microdomains is emerging as a central organizing principle in bacterial membranes. These microdomains are targets of antibiotic development and have the potential to enhance natural product synthesis, but the rules governing their assembly are unclear. Previous studies have suggested that microdomain formation is promoted by lipid phase separation, particularly by cardiolipin (CL) and isoprenoid lipids, and there is strong evidence that CL biosynthesis is required for recruitment of membrane proteins to cell poles and division sites. New work demonstrates that additional bacterial lipids may mediate membrane protein localization and function, opening the field for mechanistic evaluation of lipid-driven membrane organization in vivo.
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Affiliation(s)
- Lorna My Mitchison-Field
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, USA; Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Brittany J Belin
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, USA; Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
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16
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Demey LM, Gumerov VM, Xing J, Zhulin IB, DiRita VJ. Transmembrane Transcription Regulators Are Widespread in Bacteria and Archaea. Microbiol Spectr 2023; 11:e0026623. [PMID: 37154724 PMCID: PMC10269533 DOI: 10.1128/spectrum.00266-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
To adapt and proliferate, bacteria must sense and respond to the ever-changing environment. Transmembrane transcription regulators (TTRs) are a family of one-component transcription regulators that respond to extracellular information and influence gene expression from the cytoplasmic membrane. How TTRs function to modulate expression of their target genes while localized to the cytoplasmic membrane remains poorly understood. In part, this is due to a lack of knowledge regarding the prevalence of TTRs among prokaryotes. Here, we show that TTRs are highly diverse and prevalent throughout bacteria and archaea. Our work demonstrates that TTRs are more common than previously appreciated and are enriched within specific bacterial and archaeal phyla and that many TTRs have unique transmembrane region properties that can facilitate association with detergent-resistant membranes. IMPORTANCE One-component signal transduction systems are the major class of signal transduction systems among bacteria and are commonly cytoplasmic. TTRs are a group of unique one-component signal transduction systems that influence transcription from the cytoplasmic membrane. TTRs have been implicated in a wide array of biological pathways critical for both pathogens and human commensal organisms but were considered to be rare. Here, we demonstrate that TTRs are in fact highly diverse and broadly distributed in bacteria and archaea. Our findings suggest that transcription factors can access the chromosome and influence transcription from the membrane in both archaea and bacteria. This study challenges thus the commonly held notion that signal transduction systems require a cytoplasmic transcription factor and highlights the importance of the cytoplasmic membrane in directly influencing signal transduction.
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Affiliation(s)
- Lucas M. Demey
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Vadim M. Gumerov
- Department of Microbiology and Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio, USA
| | - Jiawei Xing
- Department of Microbiology and Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio, USA
| | - Igor B. Zhulin
- Department of Microbiology and Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio, USA
| | - Victor J. DiRita
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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17
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Stülke J, Grüppen A, Bramkamp M, Pelzer S. Bacillus subtilis, a Swiss Army Knife in Science and Biotechnology. J Bacteriol 2023; 205:e0010223. [PMID: 37140386 PMCID: PMC10210981 DOI: 10.1128/jb.00102-23] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023] Open
Abstract
Next to Escherichia coli, Bacillus subtilis is the most studied and best understood organism that also serves as a model for many important pathogens. Due to its ability to form heat-resistant spores that can germinate even after very long periods of time, B. subtilis has attracted much scientific interest. Another feature of B. subtilis is its genetic competence, a developmental state in which B. subtilis actively takes up exogenous DNA. This makes B. subtilis amenable to genetic manipulation and investigation. The bacterium was one of the first with a fully sequenced genome, and it has been subject to a wide variety of genome- and proteome-wide studies that give important insights into many aspects of the biology of B. subtilis. Due to its ability to secrete large amounts of proteins and to produce a wide range of commercially interesting compounds, B. subtilis has become a major workhorse in biotechnology. Here, we review the development of important aspects of the research on B. subtilis with a specific focus on its cell biology and biotechnological and practical applications from vitamin production to concrete healing. The intriguing complexity of the developmental programs of B. subtilis, paired with the availability of sophisticated tools for genetic manipulation, positions it at the leading edge for discovering new biological concepts and deepening our understanding of the organization of bacterial cells.
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Affiliation(s)
- Jörg Stülke
- Department of General Microbiology, Institute for Microbiology and Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | | | - Marc Bramkamp
- Institute for General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
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18
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Abstract
The formation of membrane vesicles is a common feature in all eukaryotes. Lipid rafts are the best-studied example of membrane domains for both eukaryotes and prokaryotes, and their existence also is suggested in Archaea membranes. Lipid rafts are involved in the formation of transport vesicles, endocytic vesicles, exocytic vesicles, synaptic vesicles and extracellular vesicles, as well as enveloped viruses. Two mechanisms of how rafts are involved in vesicle formation have been proposed: first, that raft proteins and/or lipids located in lipid rafts associate with coat proteins that form a budding vesicle, and second, vesicle budding is triggered by enzymatic generation of cone-shaped ceramides and inverted cone-shaped lyso-phospholipids. In both cases, induction of curvature is also facilitated by the relaxation of tension in the raft domain. In this Review, we discuss the role of raft-derived vesicles in several intracellular trafficking pathways. We also highlight their role in different pathways of endocytosis, and in the formation of intraluminal vesicles (ILVs) through budding inwards from the multivesicular body (MVB) membrane, because rafts inside MVB membranes are likely to be involved in loading RNA into ILVs. Finally, we discuss the association of glycoproteins with rafts via the glycocalyx.
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Affiliation(s)
- Karolina Sapoń
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Rafał Mańka
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Teresa Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Tadeusz Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
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19
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Abstract
Most bacteria have cell wall peptidoglycan surrounding their plasma membranes. The essential cell wall provides a scaffold for the envelope, protection against turgor pressure and is a proven drug target. Synthesis of the cell wall involves reactions that span cytoplasmic and periplasmic compartments. Bacteria carry out the last steps of cell wall synthesis along their plasma membrane. The plasma membrane in bacteria is heterogeneous and contains membrane compartments. Here, I outline findings that highlight the emerging notion that plasma membrane compartments and the cell wall peptidoglycan are functionally intertwined. I start by providing models of cell wall synthesis compartmentalization within the plasma membrane in mycobacteria, Escherichia coli, and Bacillus subtilis. Then, I revisit literature that supports a role for the plasma membrane and its lipids in modulating enzymatic reactions that synthesize cell wall precursors. I also elaborate on what is known about bacterial lateral organization of the plasma membrane and the mechanisms by which organization is established and maintained. Finally, I discuss the implications of cell wall partitioning in bacteria and highlight how targeting plasma membrane compartmentalization serves as a way to disrupt cell wall synthesis in diverse species.
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Affiliation(s)
- Alam García-Heredia
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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20
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Cyanobacterial membrane dynamics in the light of eukaryotic principles. Biosci Rep 2023; 43:232406. [PMID: 36602300 PMCID: PMC9950537 DOI: 10.1042/bsr20221269] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
Intracellular compartmentalization is a hallmark of eukaryotic cells. Dynamic membrane remodeling, involving membrane fission/fusion events, clearly is crucial for cell viability and function, as well as membrane stabilization and/or repair, e.g., during or after injury. In recent decades, several proteins involved in membrane stabilization and/or dynamic membrane remodeling have been identified and described in eukaryotes. Yet, while typically not having a cellular organization as complex as eukaryotes, also bacteria can contain extra internal membrane systems besides the cytoplasmic membranes (CMs). Thus, also in bacteria mechanisms must have evolved to stabilize membranes and/or trigger dynamic membrane remodeling processes. In fact, in recent years proteins, which were initially defined being eukaryotic inventions, have been recognized also in bacteria, and likely these proteins shape membranes also in these organisms. One example of a complex prokaryotic inner membrane system is the thylakoid membrane (TM) of cyanobacteria, which contains the complexes of the photosynthesis light reaction. Cyanobacteria are evolutionary closely related to chloroplasts, and extensive remodeling of the internal membrane systems has been observed in chloroplasts and cyanobacteria during membrane biogenesis and/or at changing light conditions. We here discuss common principles guiding eukaryotic and prokaryotic membrane dynamics and the proteins involved, with a special focus on the dynamics of the cyanobacterial TMs and CMs.
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21
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Yuan Z, Hansen SB. Cholesterol Regulation of Membrane Proteins Revealed by Two-Color Super-Resolution Imaging. MEMBRANES 2023; 13:membranes13020250. [PMID: 36837753 PMCID: PMC9966874 DOI: 10.3390/membranes13020250] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 05/15/2023]
Abstract
Cholesterol and phosphatidyl inositol 4,5-bisphosphate (PIP2) are hydrophobic molecules that regulate protein function in the plasma membrane of all cells. In this review, we discuss how changes in cholesterol concentration cause nanoscopic (<200 nm) movements of membrane proteins to regulate their function. Cholesterol is known to cluster many membrane proteins (often palmitoylated proteins) with long-chain saturated lipids. Although PIP2 is better known for gating ion channels, in this review, we will discuss a second independent function as a regulator of nanoscopic protein movement that opposes cholesterol clustering. The understanding of the movement of proteins between nanoscopic lipid domains emerged largely through the recent advent of super-resolution imaging and the establishment of two-color techniques to label lipids separate from proteins. We discuss the labeling techniques for imaging, their strengths and weakness, and how they are used to reveal novel mechanisms for an ion channel, transporter, and enzyme function. Among the mechanisms, we describe substrate and ligand presentation and their ability to activate enzymes, gate channels, and transporters rapidly and potently. Finally, we define cholesterol-regulated proteins (CRP) and discuss the role of PIP2 in opposing the regulation of cholesterol, as seen through super-resolution imaging.
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Affiliation(s)
- Zixuan Yuan
- Department of Molecular Medicine, Department of Neuroscience, UF Scripps, Jupiter, FL 33458, USA
- Department of Neuroscience UF Scripps, Jupiter, FL 33458, USA
- Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Scott B. Hansen
- Department of Molecular Medicine, Department of Neuroscience, UF Scripps, Jupiter, FL 33458, USA
- Department of Neuroscience UF Scripps, Jupiter, FL 33458, USA
- Correspondence:
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22
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Structural determinants of REMORIN nanodomain formation in anionic membranes. Biophys J 2022:S0006-3495(22)03964-9. [PMID: 36582138 DOI: 10.1016/j.bpj.2022.12.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/02/2022] [Accepted: 12/27/2022] [Indexed: 12/30/2022] Open
Abstract
Remorins are a family of multigenic plasma membrane phosphoproteins involved in biotic and abiotic plant interaction mechanisms, partnering in molecular signaling cascades. Signaling activity of remorins depends on their phosphorylation states and subsequent clustering into nanosized membrane domains. The presence of a coiled-coil domain and a C-terminal domain is crucial to anchor remorins to negatively charged membrane domains; however, the exact role of the N-terminal intrinsically disordered domain (IDD) on protein clustering and lipid interactions is largely unknown. Here, we combine chemical biology and imaging approaches to study the partitioning of group 1 remorin into anionic model membranes mimicking the inner leaflet of the plant plasma membrane. Using reconstituted membranes containing a mix of saturated and unsaturated phosphatidylcholine, phosphatidylinositol phosphates, and sterol, we investigate the clustering of remorins to the membrane and monitor the formation of nanosized membrane domains. REM1.3 promoted membrane nanodomain organization on the exposed external leaflet of both spherical lipid vesicles and flat supported lipid bilayers. Our results reveal that REM1.3 drives a mechanism allowing lipid reorganization, leading to the formation of remorin-enriched nanodomains. Phosphorylation of the N-terminal IDD by the calcium protein kinase CPK3 influences this clustering and can lead to the formation of smaller and more disperse domains. Our work reveals the phosphate-dependent involvement of the N-terminal IDD in the remorin-membrane interaction process by driving structural rearrangements at lipid-water interfaces.
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23
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Morawska LP, Kuipers OP. Transcriptome analysis and prediction of the metabolic state of stress-induced viable but non-culturable Bacillus subtilis cells. Sci Rep 2022; 12:18015. [PMID: 36289289 PMCID: PMC9605947 DOI: 10.1038/s41598-022-21102-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/22/2022] [Indexed: 01/24/2023] Open
Abstract
Many bacteria adapt their physiology and enter the viable but non-culturable state to survive prolonged exposure to adverse environmental conditions. The VBNC cells maintain active metabolism, membrane integrity and gene transcription. However, they lose the ability to form colonies on a conventional culture media. Thus, standard colony counting methods cannot detect these alive but dormant cells. The Gram-positive bacterium Bacillus subtilis was found to enter the VBNC state when pre-exposed to osmotic stress and treated with a lethal dose of kanamycin. These cells reduced their metabolic activity, ceased growth and division and became kanamycin-tolerant. Interestingly, despite active metabolism, the majority of the kanamycin tolerant cells could not be revived on LB agar. In this study, we use a robust RNA-Seq technique to elucidate the differences in transcriptional profiles of B. subtilis VBNC cells. A comparative analysis of differently expressed genes and operons performed in this study indicates high similarities in transcriptional responses of VBNC and kanamycin-sensitive cells to antibiotic treatment. Moreover, this work reveals that VBNC cells strongly upregulate genes involved in proline uptake and catabolism, suggesting a putative role of proline as nutrient in VBNC cells.
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Affiliation(s)
- Luiza P Morawska
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Oscar P Kuipers
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
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Santos AL, van Venrooy A, Reed AK, Wyderka AM, García‐López V, Alemany LB, Oliver A, Tegos GP, Tour JM. Hemithioindigo-Based Visible Light-Activated Molecular Machines Kill Bacteria by Oxidative Damage. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2203242. [PMID: 36002317 PMCID: PMC9596824 DOI: 10.1002/advs.202203242] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/26/2022] [Indexed: 06/15/2023]
Abstract
Antibiotic resistance is a growing health threat. There is an urgent and critical need to develop new antimicrobial modalities and therapies. Here, a set of hemithioindigo (HTI)-based molecular machines capable of specifically killing Gram-positive bacteria within minutes of activation with visible light (455 nm at 65 mW cm-2 ) that are safe for mammalian cells is described. Importantly, repeated exposure of bacteria to HTI does not result in detectable development of resistance. Visible light-activated HTI kill both exponentially growing bacterial cells and antibiotic-tolerant persister cells of various Gram-positive strains, including methicillin-resistant S. aureus (MRSA). Visible light-activated HTI also eliminate biofilms of S. aureus and B. subtilis in as little as 1 h after light activation. Quantification of reactive oxygen species (ROS) formation and protein carbonyls, as well as assays with various ROS scavengers, identifies oxidative damage as the underlying mechanism for the antibacterial activity of HTI. In addition to their direct antibacterial properties, HTI synergize with conventional antibiotics in vitro and in vivo, reducing the bacterial load and mortality associated with MRSA infection in an invertebrate burn wound model. To the best of the authors' knowledge, this is the first report on the antimicrobial activity of HTI-based molecular machines.
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Affiliation(s)
- Ana L. Santos
- Department of ChemistryRice UniversityHoustonTX77005USA
- IdISBA – Fundación de Investigación Sanitaria de las Islas BalearesPalma07120Spain
| | | | - Anna K. Reed
- Department of ChemistryRice UniversityHoustonTX77005USA
| | | | | | - Lawrence B. Alemany
- Department of ChemistryRice UniversityHoustonTX77005USA
- Shared Equipment AuthorityRice UniversityHoustonTX77005USA
| | - Antonio Oliver
- IdISBA – Fundación de Investigación Sanitaria de las Islas BalearesPalma07120Spain
- Servicio de MicrobiologiaHospital Universitari Son EspasesPalma07120Spain
| | - George P. Tegos
- Office of ResearchReading HospitalTower Health420 S. Fifth AvenueWest ReadingPA19611USA
| | - James M. Tour
- Department of ChemistryRice UniversityHoustonTX77005USA
- Smalley‐Curl InstituteRice UniversityHoustonTX77005USA
- Department of Materials Science and NanoengineeringRice UniversityHoustonTX77005USA
- NanoCarbon Center and the Welch Institute for Advanced MaterialsRice UniversityHoustonTX77005USA
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25
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Mycobacterial resistance to zinc poisoning requires assembly of P-ATPase-containing membrane metal efflux platforms. Nat Commun 2022; 13:4731. [PMID: 35961955 PMCID: PMC9374683 DOI: 10.1038/s41467-022-32085-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 07/18/2022] [Indexed: 11/09/2022] Open
Abstract
The human pathogen Mycobacterium tuberculosis requires a P1B-ATPase metal exporter, CtpC (Rv3270), for resistance to zinc poisoning. Here, we show that zinc resistance also depends on a chaperone-like protein, PacL1 (Rv3269). PacL1 contains a transmembrane domain, a cytoplasmic region with glutamine/alanine repeats and a C-terminal metal-binding motif (MBM). PacL1 binds Zn2+, but the MBM is required only at high zinc concentrations. PacL1 co-localizes with CtpC in dynamic foci in the mycobacterial plasma membrane, and the two proteins form high molecular weight complexes. Foci formation does not require flotillin nor the PacL1 MBM. However, deletion of the PacL1 Glu/Ala repeats leads to loss of CtpC and sensitivity to zinc. Genes pacL1 and ctpC appear to be in the same operon, and homologous gene pairs are found in the genomes of other bacteria. Furthermore, PacL1 colocalizes and functions redundantly with other PacL orthologs in M. tuberculosis. Overall, our results indicate that PacL proteins may act as scaffolds that assemble P-ATPase-containing metal efflux platforms mediating bacterial resistance to metal poisoning. The human pathogen Mycobacterium tuberculosis requires a metal exporter, CtpC, for resistance to zinc poisoning. Here, the authors show that zinc resistance also depends on a chaperone-like protein that binds zinc ions, forms high-molecular-weight complexes with CtpC in the cytoplasmic membrane, and is required for CtpC function.
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Gupta S, Mandal T. Simulation study of domain formation in a model bacterial membrane. Phys Chem Chem Phys 2022; 24:18133-18143. [PMID: 35856570 DOI: 10.1039/d2cp01873j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent experimental studies revealed that functional membrane microdomains (FMMs) are formed in prokaryotic cells which are structurally and functionally similar to the lipid rafts formed in eukaryotic cells. In this study, we employ coarse-grained molecular dynamics simulations to investigate the mechanism of domain formation and its physiochemical properties in a model methicillin-resistant staphylococcus aureus (MRSA) cell membrane. We find that domains are formed through lateral segregation of staphyloxanthin (STX), a carotenoid which shields the bacteria from the host's immune because of its antioxidant nature. Simulation results suggest that membrane integrity increases with the size of the domain, which is assessed by computing bond order parameter of the lipid tails, membrane expansion modulus and water permeability across the membrane. Various membrane domain proteins such as flotillin-like protein floA and penicillin binding protein (PBP2a) preferentially bind with the STX and accumulate in the membrane domain which is consistent with the recent experimental results.
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Affiliation(s)
- Shivam Gupta
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Taraknath Mandal
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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27
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van Aalst EJ, Borcik CG, Wylie BJ. Spectroscopic signatures of bilayer ordering in native biological membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183891. [PMID: 35217001 PMCID: PMC10793244 DOI: 10.1016/j.bbamem.2022.183891] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
Membrane proteins and polycyclic lipids like cholesterol and hopanoids coordinate phospholipid bilayer ordering. This phenomenon manifests as partitioning of the liquid crystalline phase into liquid-ordered (Lo) and liquid-disordered (Ld) regions. In Eukaryotes, microdomains are rich in cholesterol and sphingolipids and serve as signal transduction scaffolds. In Prokaryotes, Lo microdomains increase pathogenicity and antimicrobial resistance. Previously, we identified spectroscopically distinct chemical shift signatures for all-trans (AT) and trans-gauche (TG) acyl chain conformations, cyclopropyl ring lipids (CPR), and hopanoids in prokaryotic lipid extracts and used Polarization Transfer (PT) SSNMR to investigate bilayer ordering. To investigate how these findings relate to native bilayer organization, we interrogate whole cell and whole membrane extract samples of Burkholderia thailendensis to investigate bilayer ordering in situ. In 13C-13C 2D SSNMR spectra, we assigned chemical shifts for lipid species in both samples, showing conservation of lipids of interest in our native membrane sample. A one-dimensional temperature series of PT SSNMR and transverse relaxation measurements of AT versus TG acyl conformations in the membrane sample confirm bilayer ordering and a broadened phase transition centered at a lower-than-expected temperature. Bulk protein backbone Cα dynamics and correlations consistent with lipid-protein contacts within are further indicative of microdomain formation and lipid ordering. In aggregate, these findings provide evidence for microdomain formation in vivo and provide insight into phase separation and transition mechanics in biological membranes.
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Affiliation(s)
- Evan J van Aalst
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79415, USA
| | - Collin G Borcik
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79415, USA
| | - Benjamin J Wylie
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79415, USA.
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28
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Vélez M. How Does the Spatial Confinement of FtsZ to a Membrane Surface Affect Its Polymerization Properties and Function? Front Microbiol 2022; 13:757711. [PMID: 35592002 PMCID: PMC9111741 DOI: 10.3389/fmicb.2022.757711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 01/27/2022] [Indexed: 11/15/2022] Open
Abstract
FtsZ is the cytoskeletal protein that organizes the formation of the septal ring and orchestrates bacterial cell division. Its association to the membrane is essential for its function. In this mini-review I will address the question of how this association can interfere with the structure and dynamic properties of the filaments and argue that its dynamics could also remodel the underlying lipid membrane through its activity. Thus, lipid rearrangement might need to be considered when trying to understand FtsZ’s function. This new element could help understand how FtsZ assembly coordinates positioning and recruitment of the proteins forming the septal ring inside the cell with the activity of the machinery involved in peptidoglycan synthesis located in the periplasmic space.
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Affiliation(s)
- Marisela Vélez
- Instituto de Catálisis y Petroleoquímica, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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29
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Celastrol mitigates staphyloxanthin biosynthesis and biofilm formation in Staphylococcus aureus via targeting key regulators of virulence; in vitro and in vivo approach. BMC Microbiol 2022; 22:106. [PMID: 35421933 PMCID: PMC9011992 DOI: 10.1186/s12866-022-02515-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/01/2022] [Indexed: 12/18/2022] Open
Abstract
Abstract
Background
Staphylococcus aureus is a leading cause of human infections. The spread of antibiotic-resistant staphylococci has driven the search for novel strategies to supersede antibiotics use. Thus, targeting bacterial virulence rather than viability could be a possible alternative.
Results
The influence of celastrol on staphyloxanthin (STX) biosynthesis, biofilm formation, antibiotic susceptibility and host pathogenesis in S. aureus has been investigated. Celastrol efficiently reduced STX biosynthesis in S. aureus. Liquid chromatography-mass spectrometry (LC–MS) and molecular docking revealed that celastrol inhibits STX biosynthesis through its effect on CrtM. Quantitative measurement of STX intermediates showed a significant pigment inhibition via interference of celastrol with CrtM and accumulation of its substrate, farnesyl diphosphate. Importantly, celastrol-treated S. aureus was more sensitive to environmental stresses and human blood killing than untreated bacteria. Similarly, inhibition of STX upon celastrol treatment rendered S. aureus more susceptible to membrane targeting antibiotics. In addition to its anti-pigment capability, celastrol exhibits significant anti-biofilm activity against S. aureus as indicated by crystal violet assay and microscopy. Celastrol-treated cells showed deficient exopolysaccharide production and cell hydrophobicity. Moreover, celastrol markedly synergized the action of conventional antibiotics against S. aureus and reduced bacterial pathogenesis in vivo using mice infection model. These findings were further validated using qRT-PCR, demonstrating that celastrol could alter the expression of STX biosynthesis genes as well as biofilm formation related genes and bacterial virulence.
Conclusions
Celastrol is a novel anti-virulent agent against S. aureus suggesting, a prospective therapeutic role for celastrol as a multi-targeted anti-pathogenic agent.
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30
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Ma C, Wang C, Luo D, Yan L, Yang W, Li N, Gao N. Structural insights into the membrane microdomain organization by SPFH family proteins. Cell Res 2022; 32:176-189. [PMID: 34975153 PMCID: PMC8807802 DOI: 10.1038/s41422-021-00598-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 11/09/2021] [Indexed: 02/03/2023] Open
Abstract
The lateral segregation of membrane constituents into functional microdomains, conceptually known as lipid raft, is a universal organization principle for cellular membranes in both prokaryotes and eukaryotes. The widespread Stomatin, Prohibitin, Flotillin, and HflK/C (SPFH) family proteins are enriched in functional membrane microdomains at various subcellular locations, and therefore were hypothesized to play a scaffolding role in microdomain formation. In addition, many SPFH proteins are also implicated in highly specific processes occurring on the membrane. However, none of these functions is understood at the molecular level. Here we report the structure of a supramolecular complex that is isolated from bacterial membrane microdomains and contains two SPFH proteins (HflK and HflC) and a membrane-anchored AAA+ protease FtsH. HflK and HflC form a circular 24-mer assembly, featuring a laterally segregated membrane microdomain (20 nm in diameter) bordered by transmembrane domains of HflK/C and a completely sealed periplasmic vault. Four FtsH hexamers are embedded inside this microdomain through interactions with the inner surface of the vault. These observations provide a mechanistic explanation for the role of HflK/C and their mitochondrial homologs prohibitins in regulating membrane-bound AAA+ proteases, and suggest a general model for the organization and functionalization of membrane microdomains by SPFH proteins.
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Affiliation(s)
- Chengying Ma
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Chengkun Wang
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Dingyi Luo
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Lu Yan
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Wenxian Yang
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ningning Li
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ning Gao
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Centre for Life Sciences, School of Life Sciences, Peking University, Beijing, China ,grid.11135.370000 0001 2256 9319National Biomedical Imaging Center, Peking University, Beijing, China
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Chafsey I, Ostrowski R, Guilbaud M, Teixeira P, Herry JM, Caccia N, Chambon C, Hébraud M, Azeredo J, Bellon-Fontaine MN, Popowska M, Desvaux M. Deep impact of the inactivation of the SecA2-only protein export pathway on the proteosurfaceome of Listeria monocytogenes. J Proteomics 2022; 250:104388. [PMID: 34601155 DOI: 10.1016/j.jprot.2021.104388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/17/2021] [Accepted: 09/20/2021] [Indexed: 01/23/2023]
Abstract
Listeria monocytogenes presents a dimorphism associated to the SecA2 activity with cells having a normal rod shape or a dysmorphic elongated filamentous form. Besides variation of the cell and colony morphotype, this cell differentiation has profound ecophysiological and physiopathological implications with collateral effects on virulence and pathogenicity, biotope colonisation, bacterial adhesion and biofilm formation. This suggests the SecA2-only protein export could influence the listerial cell surface, which was investigated first by characterising its properties in L. monocytogenes wt and ΔsecA2. The degree of hydrophilicity and Lewis acid-base properties appeared significantly affected upon SecA2 inactivation. As modification of electrostatic properties would owe to modification in the composition of cell-surface proteins, the proteosurfaceome was further investigated by shotgun label-free proteomic analysis with a comparative relative quantitative approach. Following secretomic analysis, the protein secretion routes of the identified proteins were mapped considering the cognate transport and post-translocational maturation systems, as well as protein categories and subcellular localisation. Differential protein abundance profiles coupled to network analysis revealed the SecA2 dependence of 48 proteins, including some related to cell envelope biogenesis, translation and protein export, which could account for modifications of adhesion and surface properties of L. monocytogenes upon SecA2 inactivation. This investigation unravelled the profound influence of SecA2 activity on the cell surface properties and proteosurfaceome of L. monocytogenes, which provides advanced insights about its ecophysiopathology. SIGNIFICANCE: L. monocytogenes is a foodborne zoonotic pathogen and etiological agent of human listeriosis. This species presents a cellular dimorphism associated to the SecA2 activity that has profound physiopathological and ecophysiological implications with collateral effects on bacterial virulence and colonisation. To explore the influence of the SecA2-only protein export on the listerial cell, the surface properties of L. monocytogenes expressing or depleted of SecA2 was characterised by microelectrophoresis, microbial affinity to solvents and contact angles analyses. As modifications of hydrophilicity and Lewis acid-base electrostatic properties would owe to modification in the composition of cell-surface proteins, the proteinaceous subset of the surfaceome, i.e. the proteosurfaceome, was investigated further by shotgun label-free proteomic analysis. This subproteome appeared quite impacted upon SecA2 inactivation with the identification of proteins accounting for modifications in the cell surface properties. The profound influence of SecA2 activity on the cell surface of L. monocytogenes was unravelled, which provides advanced insights about its ecophysiopathology.
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Affiliation(s)
- Ingrid Chafsey
- INRAE, Université Clermont Auvergne, UMR454 MEDiS, 63000 Clermont-Ferrand, France
| | - Rafal Ostrowski
- University of Warsaw, Faculty of Biology, Department of Bacterial Physiology, Applied Microbiology, Institute of Microbiology, Warsaw, Poland
| | - Morgan Guilbaud
- Université Paris-Saclay, INRAE, AgroParisTech, UMR SayFood, 91300 Massy, France
| | - Pilar Teixeira
- University of Minho, Centre of Biological Engineering, Campus de Gualtar, Braga 4710-057, Portugal
| | - Jean-Marie Herry
- Université Paris-Saclay, INRAE, AgroParisTech, UMR SayFood, 91300 Massy, France
| | - Nelly Caccia
- INRAE, Université Clermont Auvergne, UMR454 MEDiS, 63000 Clermont-Ferrand, France
| | - Christophe Chambon
- INRAE, Plateforme d'Exploration du Métabolisme, 63122 Saint-Genès Champanelle, France
| | - Michel Hébraud
- INRAE, Université Clermont Auvergne, UMR454 MEDiS, 63000 Clermont-Ferrand, France; INRAE, Plateforme d'Exploration du Métabolisme, 63122 Saint-Genès Champanelle, France
| | - Joana Azeredo
- University of Minho, Centre of Biological Engineering, Campus de Gualtar, Braga 4710-057, Portugal
| | | | - Magdalena Popowska
- University of Warsaw, Faculty of Biology, Department of Bacterial Physiology, Applied Microbiology, Institute of Microbiology, Warsaw, Poland.
| | - Mickaël Desvaux
- INRAE, Université Clermont Auvergne, UMR454 MEDiS, 63000 Clermont-Ferrand, France.
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32
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de Carvalho CCCR, Taglialegna A, Rosato AE. Impact of PrsA on membrane lipid composition during daptomycin-resistance-mediated β-lactam sensitization in clinical MRSA strains. J Antimicrob Chemother 2021; 77:135-147. [PMID: 34618036 PMCID: PMC8730685 DOI: 10.1093/jac/dkab356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 08/28/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The cyclic anionic lipopeptide daptomycin is used in the treatment of severe infections caused by Gram-positive pathogens, including MRSA. Daptomycin resistance, although rare, often results in treatment failure. Paradoxically, in MRSA, daptomycin resistance is usually accompanied by a concomitant decrease in β-lactam resistance in what is known as the 'see-saw effect'. This resensitization is extensively used for the treatment of MRSA infections, by combining daptomycin and a β-lactam antibiotic, such as oxacillin. OBJECTIVES We aimed: (i) to investigate the combined effects of daptomycin and oxacillin on the lipid composition of the cellular membrane of both daptomycin-resistant and -susceptible MRSA strains; and (ii) to assess the involvement of the post-translocational protein PrsA, which plays an important role in oxacillin resistance in MRSA, in membrane lipid composition and remodelling during daptomycin resistance/β-lactam sensitization. RESULTS The combination of microbiological and biochemical studies, with fluorescence microscopy using lipid probes, showed that the lipid composition and surface charge of the daptomycin-resistant cells exposed to daptomycin/oxacillin were dependent on antibiotic concentration and directly associated with PrsA, which influenced cardiolipin remodelling/relocation. CONCLUSIONS Our findings show that PrsA, in addition to its post-transcriptional role in the maturation of PBP 2a, is a key mediator of cell membrane remodelling connected to the see-saw effect and may have a key role in the resensitization of daptomycin-resistant strains to β-lactams, such as oxacillin.
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Affiliation(s)
- Carla C C R de Carvalho
- iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Agustina Taglialegna
- Department of Pathology and Genomic Medicine, Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, TX, USA
| | - Adriana E Rosato
- Department of Pathology and Genomic Medicine, Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, TX, USA
- Department of Pathology and Molecular Microbiology Diagnostics-Research, Riverside University Health System, 26520 Cactus Avenue, Moreno Valley, CA 92555, USA
- University of California, Riverside, CA, USA
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Czolkoss S, Safronov X, Rexroth S, Knoke LR, Aktas M, Narberhaus F. Agrobacterium tumefaciens Type IV and Type VI Secretion Systems Reside in Detergent-Resistant Membranes. Front Microbiol 2021; 12:754486. [PMID: 34899640 PMCID: PMC8656257 DOI: 10.3389/fmicb.2021.754486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Cell membranes are not homogenous but compartmentalized into lateral microdomains, which are considered as biochemical reaction centers for various physiological processes in eukaryotes and prokaryotes. Due to their special lipid and protein composition, some of these microdomains are resistant to treatment with non-ionic detergents and can be purified as detergent-resistant membranes (DRMs). Here we report the proteome of DRMs from the Gram-negative phytopathogen Agrobacterium tumefaciens. Using label-free liquid chromatography-tandem mass spectrometry, we identified proteins enriched in DRMs isolated under normal and virulence-mimicking growth conditions. Prominent microdomain marker proteins such as the SPFH (stomatin/prohibitin/flotillin/HflKC) proteins HflK, HflC and Atu3772, along with the protease FtsH were highly enriched in DRMs isolated under any given condition. Moreover, proteins involved in cell envelope biogenesis, transport and secretion, as well as motility- and chemotaxis-associated proteins were overrepresented in DRMs. Most strikingly, we found virulence-associated proteins such as the VirA/VirG two-component system, and the membrane-spanning type IV and type VI secretion systems enriched in DRMs. Fluorescence microscopy of the cellular localization of both secretion systems and of marker proteins was in agreement with the results from the proteomics approach. These findings suggest that virulence traits are micro-compartmentalized into functional microdomains in A. tumefaciens.
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Affiliation(s)
- Simon Czolkoss
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Xenia Safronov
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Sascha Rexroth
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Lisa R Knoke
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Meriyem Aktas
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Franz Narberhaus
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
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Cruz A, Condinho M, Carvalho B, Arraiano CM, Pobre V, Pinto SN. The Two Weapons against Bacterial Biofilms: Detection and Treatment. Antibiotics (Basel) 2021; 10:1482. [PMID: 34943694 PMCID: PMC8698905 DOI: 10.3390/antibiotics10121482] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 12/12/2022] Open
Abstract
Bacterial biofilms are defined as complex aggregates of bacteria that grow attached to surfaces or are associated with interfaces. Bacteria within biofilms are embedded in a self-produced extracellular matrix made of polysaccharides, nucleic acids, and proteins. It is recognized that bacterial biofilms are responsible for the majority of microbial infections that occur in the human body, and that biofilm-related infections are extremely difficult to treat. This is related with the fact that microbial cells in biofilms exhibit increased resistance levels to antibiotics in comparison with planktonic (free-floating) cells. In the last years, the introduction into the market of novel compounds that can overcome the resistance to antimicrobial agents associated with biofilm infection has slowed down. If this situation is not altered, millions of lives are at risk, and this will also strongly affect the world economy. As such, research into the identification and eradication of biofilms is important for the future of human health. In this sense, this article provides an overview of techniques developed to detect and imaging biofilms as well as recent strategies that can be applied to treat biofilms during the several biofilm formation steps.
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Affiliation(s)
- Adriana Cruz
- iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal;
- i4HB—Institute for Health and Bioeconomy, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Manuel Condinho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal; (M.C.); (B.C.); (C.M.A.)
| | - Beatriz Carvalho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal; (M.C.); (B.C.); (C.M.A.)
| | - Cecília M. Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal; (M.C.); (B.C.); (C.M.A.)
| | - Vânia Pobre
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal; (M.C.); (B.C.); (C.M.A.)
| | - Sandra N. Pinto
- iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal;
- i4HB—Institute for Health and Bioeconomy, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
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van Tilburg AY, Warmer P, van Heel AJ, Sauer U, Kuipers OP. Membrane composition and organization of Bacillus subtilis 168 and its genome-reduced derivative miniBacillus PG10. Microb Biotechnol 2021; 15:1633-1651. [PMID: 34856064 PMCID: PMC9049611 DOI: 10.1111/1751-7915.13978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/13/2021] [Accepted: 11/14/2021] [Indexed: 11/30/2022] Open
Abstract
A form of lateral membrane compartmentalization in bacteria is represented by functional membrane microdomains (FMMs). FMMs are important for various cellular processes and offer application possibilities in microbial biotechnology. We designed a lipidomics method to directly measure relative abundances of lipids in detergent‐resistant and detergent‐sensitive membrane fractions of the model bacterium Bacillus subtilis 168 and the biotechnologically attractive miniBacillus PG10 strain. Our study supports previous work suggesting that cardiolipin and prenol lipids are enriched in FMMs of B. subtilis. Additionally, structural analysis of acyl chains of major phospholipids indicated that FMMs display increased order and thickness compared with the surrounding bilayer. Despite the 36% genome reduction, membrane and FMM integrity are largely preserved in miniBacillus PG10, as supported by analysis of membrane fluidity, flotillin distribution and gene expression data. The novel insights in FMM architecture reported here will contribute to further explore the biological significance of FMMs and the means by which FMMs can be exploited as heterologous production platforms. Moreover, our lipidomics method enables comparative FMM lipid profiling between different bacteria.
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Affiliation(s)
- Amanda Y van Tilburg
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Philipp Warmer
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland.,Life Science Zürich PhD Program on Systems Biology, Zürich, Switzerland
| | - Auke J van Heel
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Uwe Sauer
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Oscar P Kuipers
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
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36
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Lv X, Jin K, Sun G, Ledesma-Amaro R, Liu L. Microscopy imaging of living cells in metabolic engineering. Trends Biotechnol 2021; 40:752-765. [PMID: 34799183 DOI: 10.1016/j.tibtech.2021.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 01/23/2023]
Abstract
Microscopy imaging of living cells is becoming a pivotal, noninvasive, and highly specific tool in metabolic engineering to visualize molecular dynamics in industrial microorganisms. This review describes the different microscopy methods, from fluorescence to super resolution, with application in microbial bioengineering. Firstly, the role and importance of microscopy imaging is analyzed in the context of strain design. Then, the advantages and disadvantages of different microscopy technologies are discussed, including confocal laser scanning microscopy (CLSM), spatial light interference microscopy (SLIM), and super-resolution microscopy, followed by their applications in synthetic biology. Finally, the future perspectives of live-cell imaging and their potential to transform microbial systems are analyzed. This review provides theoretical guidance and highlights the importance of microscopy in understanding and engineering microbial metabolism.
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Affiliation(s)
- Xueqin Lv
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
| | - Ke Jin
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
| | - Guoyun Sun
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
| | - Rodrigo Ledesma-Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London SW72AZ, UK
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China.
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37
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Scholz AS, Baur SSM, Wolf D, Bramkamp M. An Stomatin, Prohibitin, Flotillin, and HflK/C-Domain Protein Required to Link the Phage-Shock Protein to the Membrane in Bacillus subtilis. Front Microbiol 2021; 12:754924. [PMID: 34777311 PMCID: PMC8581546 DOI: 10.3389/fmicb.2021.754924] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 09/27/2021] [Indexed: 11/28/2022] Open
Abstract
Membrane surveillance and repair is of utmost importance to maintain cellular integrity and allow cellular life. Several systems detect cell envelope stress caused by antimicrobial compounds and abiotic stresses such as solvents, pH-changes and temperature in bacteria. Proteins containing an Stomatin, Prohibitin, Flotillin, and HflK/C (SPFH)-domain, including bacterial flotillins have been shown to be involved in membrane protection and membrane fluidity regulation. Here, we characterize a bacterial SPFH-domain protein, YdjI that is part of a stress induced complex in Bacillus subtilis. We show that YdjI is required to localize the ESCRT-III homolog PspA to the membrane with the help of two membrane integral proteins, YdjG/H. In contrast to classical flotillins, YdjI resides in fluid membrane regions and does not enrich in detergent resistant membrane fractions. However, similarly to FloA and FloT from B. subtilis, deletion of YdjI decreases membrane fluidity. Our data reveal a hardwired connection between phage shock response and SPFH proteins.
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Affiliation(s)
- Abigail Savietto Scholz
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sarah S. M. Baur
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Diana Wolf
- Institute of Microbiology, Technische Universität Dresden, Dresden, Germany
| | - Marc Bramkamp
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
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38
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Rizk S, Henke P, Santana-Molina C, Martens G, Gnädig M, Nguyen NA, Devos DP, Neumann-Schaal M, Saenz JP. Functional diversity of isoprenoid lipids in Methylobacterium extorquens PA1. Mol Microbiol 2021; 116:1064-1078. [PMID: 34387371 DOI: 10.1111/mmi.14794] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/29/2021] [Accepted: 08/10/2021] [Indexed: 11/29/2022]
Abstract
Hopanoids and carotenoids are two of the major isoprenoid-derived lipid classes in prokaryotes that have been proposed to have similar membrane ordering properties as sterols. Methylobacterium extorquens contains hopanoids and carotenoids in their outer membrane, making them an ideal system to investigate the role of isoprenoid lipids in surface membrane function and cellular fitness. By genetically knocking out hpnE, and crtB we disrupted the production of squalene, and phytoene in Methylobacterium extorquens PA1, which are the presumed precursors for hopanoids and carotenoids, respectively. Deletion of hpnE revealed that carotenoid biosynthesis utilizes squalene as a precursor resulting in pigmentation with a C30 backbone, rather than the previously predicted canonical C40 phytoene-derived pathway. Phylogenetic analysis suggested that M. extorquens may have acquired the C30 pathway through lateral gene transfer from Planctomycetes. Surprisingly, disruption of carotenoid synthesis did not generate any major growth or membrane biophysical phenotypes, but slightly increased sensitivity to oxidative stress. We further demonstrated that hopanoids but not carotenoids are essential for growth at higher temperatures, membrane permeability and tolerance of low divalent cation concentrations. These observations show that hopanoids and carotenoids serve diverse roles in the outer membrane of M. extorquens PA1.
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Affiliation(s)
- Sandra Rizk
- Technische Universität Dresden, B CUBE, Dresden, Germany
| | - Petra Henke
- Bacterial Metabolomics, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Carlos Santana-Molina
- Centro Andaluz de Biologıa del Desarrollo (CABD)-CSIC, Junta de Andalucıa, Universidad Pablo de Olavide, Seville, Spain
| | - Gesa Martens
- Bacterial Metabolomics, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Marén Gnädig
- Technische Universität Dresden, B CUBE, Dresden, Germany
| | | | - Damien P Devos
- Centro Andaluz de Biologıa del Desarrollo (CABD)-CSIC, Junta de Andalucıa, Universidad Pablo de Olavide, Seville, Spain
| | - Meina Neumann-Schaal
- Bacterial Metabolomics, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - James P Saenz
- Technische Universität Dresden, B CUBE, Dresden, Germany
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Visualization and Analysis of the Dynamic Assembly of a Heterologous Lantibiotic Biosynthesis Complex in Bacillus subtilis. mBio 2021; 12:e0121921. [PMID: 34281399 PMCID: PMC8406302 DOI: 10.1128/mbio.01219-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A membrane-associated lanthipeptide synthetase complex, consisting of the dehydratase NisB, the cyclase NisC, and the ABC transporter NisT, has been described for nisin biosynthesis in the coccoid bacterium Lactococcus lactis. Here, we used advanced fluorescence microscopy to visualize the functional nisin biosynthesis machinery in rod-shaped cells and analyzed its spatial distribution and dynamics employing a platform we developed for heterologous production of nisin in Bacillus subtilis. We observed that NisT, as well as NisB and NisC, were all distributed in a punctate pattern along the cell periphery, opposed to the situation in coccoid cells. NisBTC proteins were found to be highly colocalized, being visualized at the same spots by dual fluorescence microscopy. In conjunction with the successful isolation of the biosynthetic complex NisBTC from the cell membrane, this corroborated that the visual bright foci were the sites for nisin maturation and transportation. A strategy of differential timing of expression was employed to demonstrate the in vivo dynamic assembly of NisBTC, revealing the recruitment by NisT of NisBC to the membrane. Additionally, by use of mutated proteins, the nucleotide binding domain (NBD) of NisT was found to function as a membrane anchor for NisB and/or NisC. We also show that the nisin biosynthesis sites are static and likely associated with proteins residing in lipid rafts. Based on these data, we propose a model for a three-phase production of modified precursor nisin in rod-shaped bacteria, presenting the assembly dynamics of NisBTC and emphasizing the crucial role of NisBC, next to NisT, in the process of precursor nisin translocation.
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40
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York A, Lloyd AJ, Del Genio CI, Shearer J, Hinxman KJ, Fritz K, Fulop V, Dowson CG, Khalid S, Roper DI. Structure-based modeling and dynamics of MurM, a Streptococcus pneumoniae penicillin resistance determinant present at the cytoplasmic membrane. Structure 2021; 29:731-742.e6. [PMID: 33740396 PMCID: PMC8280954 DOI: 10.1016/j.str.2021.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 01/13/2021] [Accepted: 03/01/2021] [Indexed: 11/28/2022]
Abstract
Branched Lipid II, required for the formation of indirectly crosslinked peptidoglycan, is generated by MurM, a protein essential for high-level penicillin resistance in the human pathogen Streptococcus pneumoniae. We have solved the X-ray crystal structure of Staphylococcus aureus FemX, an isofunctional homolog, and have used this as a template to generate a MurM homology model. Using this model, we perform molecular docking and molecular dynamics to examine the interaction of MurM with the phospholipid bilayer and the membrane-embedded Lipid II substrate. Our model suggests that MurM is associated with the major membrane phospholipid cardiolipin, and experimental evidence confirms that the activity of MurM is enhanced by this phospholipid and inhibited by its direct precursor phosphatidylglycerol. The spatial association of pneumococcal membrane phospholipids and their impact on MurM activity may therefore be critical to the final architecture of peptidoglycan and the expression of clinically relevant penicillin resistance in this pathogen.
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Affiliation(s)
- Anna York
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Adrian J Lloyd
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Charo I Del Genio
- Centre for Fluid and Complex Systems, School of Computing, Electronics and Mathematics, University of Coventry, West Midlands CV1 5FB, UK
| | - Jonathan Shearer
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, UK
| | - Karen J Hinxman
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Konstantin Fritz
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Vilmos Fulop
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Christopher G Dowson
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, UK.
| | - David I Roper
- School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK; Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, USA.
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41
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Willdigg JR, Helmann JD. Mini Review: Bacterial Membrane Composition and Its Modulation in Response to Stress. Front Mol Biosci 2021; 8:634438. [PMID: 34046426 PMCID: PMC8144471 DOI: 10.3389/fmolb.2021.634438] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 04/13/2021] [Indexed: 11/13/2022] Open
Abstract
Antibiotics and other agents that perturb the synthesis or integrity of the bacterial cell envelope trigger compensatory stress responses. Focusing on Bacillus subtilis as a model system, this mini-review summarizes current views of membrane structure and insights into how cell envelope stress responses remodel and protect the membrane. Altering the composition and properties of the membrane and its associated proteome can protect cells against detergents, antimicrobial peptides, and pore-forming compounds while also, indirectly, contributing to resistance against compounds that affect cell wall synthesis. Many of these regulatory responses are broadly conserved, even where the details of regulation may differ, and can be important in the emergence of antibiotic resistance in clinical settings.
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Affiliation(s)
| | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, United States
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42
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Lundgren CAK, Lerche M, Norling C, Högbom M. Solution and Membrane Interaction Dynamics of Mycobacterium tuberculosis Fatty Acyl-CoA Synthetase FadD13. Biochemistry 2021; 60:1520-1532. [PMID: 33913324 PMCID: PMC8253482 DOI: 10.1021/acs.biochem.0c00987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The very-long-chain fatty acyl-CoA synthetase FadD13 from Mycobacterium tuberculosis activates fatty acids for further use in mycobacterial lipid metabolism. FadD13 is a peripheral membrane protein, with both soluble and membrane-bound populations in vivo. The protein displays a distinct positively charged surface patch, suggested to be involved in membrane association. In this paper, we combine structural analysis with liposome co-flotation assays and membrane association modeling to gain a more comprehensive understanding of the mechanisms behind membrane association. We show that FadD13 has affinity for negatively charged lipids, such as cardiolipin. Addition of a fatty acid substrate to the liposomes increases the apparent affinity of FadD13, consistent with our previous hypothesis that FadD13 can utilize the membrane to harbor its very-long-chain fatty acyl substrates. In addition, we unambiguously show that FadD13 adopts a dimeric arrangement in solution. The dimer interface partly buries the positive surface patch, seemingly inconsistent with membrane binding. Notably, when cross-linking the dimer, it lost its ability to bind and co-migrate with liposomes. To better understand the dynamics of association, we utilized two mutant variants of FadD13, one in which the positively charged patch was altered to become more negative and one more hydrophobic. Both variants were predominantly monomeric in solution. The hydrophobic variant maintained the ability to bind to the membrane, whereas the negative variant did not. Taken together, our data indicate that FadD13 exists in a dynamic equilibrium between the dimer and monomer, where the monomeric state can adhere to the membrane via the positively charged surface patch.
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Affiliation(s)
- Camilla A K Lundgren
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Michael Lerche
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Charlotta Norling
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
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43
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Sharipova MR, Mardanova AM, Rudakova NL, Pudova DS. Bistability and Formation of the Biofilm Matrix as Adaptive Mechanisms during the Stationary Phase of Bacillus subtilis. Microbiology (Reading) 2021. [DOI: 10.1134/s002626172006017x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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44
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Abstract
Bacteria possess a sophisticated arsenal of defense mechanisms that allow them to survive in adverse conditions. Adaptation to acid stress and hypoxia is crucial for the enterobacterial transmission in the gastrointestinal tract of their human host. When subjected to low pH, Escherichia coli and many other enterobacteria activate a proton-consuming resistance system based on the acid stress-inducible lysine decarboxylase LdcI. Here we develop generally applicable tools to uncover the spatial localization of LdcI inside the cell by superresolution fluorescence microscopy and investigate the in vitro supramolecular organization of this enzyme by cryo-EM. We build on these results to propose a mechanistic model for LdcI function and offer tools for further in vivo investigations. Pathogenic and commensal bacteria often have to resist the harsh acidity of the host stomach. The inducible lysine decarboxylase LdcI buffers the cytosol and the local extracellular environment to ensure enterobacterial survival at low pH. Here, we investigate the acid stress-response regulation of Escherichia coli LdcI by combining biochemical and biophysical characterization with negative stain and cryoelectron microscopy (cryo-EM) and wide-field and superresolution fluorescence imaging. Due to deleterious effects of fluorescent protein fusions on native LdcI decamers, we opt for three-dimensional localization of nanobody-labeled endogenous wild-type LdcI in acid-stressed E. coli cells and show that it organizes into distinct patches at the cell periphery. Consistent with recent hypotheses that in vivo clustering of metabolic enzymes often reflects their polymerization as a means of stimulus-induced regulation, we show that LdcI assembles into filaments in vitro at physiologically relevant low pH. We solve the structures of these filaments and of the LdcI decamer formed at neutral pH by cryo-EM and reveal the molecular determinants of LdcI polymerization, confirmed by mutational analysis. Finally, we propose a model for LdcI function inside the enterobacterial cell, providing a structural and mechanistic basis for further investigation of the role of its supramolecular organization in the acid stress response.
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45
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Wolter LA, Wietz M, Ziesche L, Breider S, Leinberger J, Poehlein A, Daniel R, Schulz S, Brinkhoff T. Pseudooceanicola algae sp. nov., isolated from the marine macroalga Fucus spiralis, shows genomic and physiological adaptations for an algae-associated lifestyle. Syst Appl Microbiol 2021; 44:126166. [PMID: 33310406 DOI: 10.1016/j.syapm.2020.126166] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/09/2020] [Accepted: 11/12/2020] [Indexed: 12/23/2022]
Abstract
The genus Pseudooceanicola from the alphaproteobacterial Roseobacter group currently includes ten validated species. We herein describe strain Lw-13eT, the first Pseudooceanicola species from marine macroalgae, isolated from the brown alga Fucus spiralis abundant at European and North American coasts. Physiological and pangenome analyses of Lw-13eT showed corresponding adaptive features. Adaptations to the tidal environment include a broad salinity tolerance, degradation of macroalgae-derived substrates (mannitol, mannose, proline), and resistance to several antibiotics and heavy metals. Notably, Lw-13eT can degrade oligomeric alginate via PL15 alginate lyase encoded in a polysaccharide utilization locus (PUL), rarely described for roseobacters to date. Plasmid localization of the PUL strengthens the importance of mobile genetic elements for evolutionary adaptations within the Roseobacter group. PL15 homologs were primarily detected in marine plant-associated metagenomes from coastal environments but not in the open ocean, corroborating its adaptive role in algae-rich habitats. Exceptional is the tolerance of Lw-13eT against the broad-spectrum antibiotic tropodithietic acid, produced by Phaeobacter spp. co-occurring in coastal habitats. Furthermore, Lw-13eT exhibits features resembling terrestrial plant-bacteria associations, i.e. biosynthesis of siderophores, terpenes and volatiles, which may contribute to mutual bacteria-algae interactions. Closest described relative of Lw-13eT is Pseudopuniceibacterium sediminis CY03T with 98.4% 16S rRNA gene sequence similarity. However, protein sequence-based core genome phylogeny and average nucleotide identity indicate affiliation of Lw-13eT with the genus Pseudooceanicola. Based on phylogenetic, physiological and (chemo)taxonomic distinctions, we propose strain Lw-13eT (=DSM 29013T=LMG 30557T) as a novel species with the name Pseudooceanicola algae.
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Affiliation(s)
- Laura A Wolter
- Institute for Chemistry and Biology of the Marine Environment, Oldenburg, Germany; JST ERATO Nomura Project, Faculty of Life and Environmental Sciences, Tsukuba, Japan.
| | - Matthias Wietz
- Institute for Chemistry and Biology of the Marine Environment, Oldenburg, Germany; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Lisa Ziesche
- Institute of Organic Chemistry, Technische Universität Braunschweig, Germany
| | - Sven Breider
- Institute for Chemistry and Biology of the Marine Environment, Oldenburg, Germany
| | - Janina Leinberger
- Institute for Chemistry and Biology of the Marine Environment, Oldenburg, Germany
| | - Anja Poehlein
- Institute of Microbiology and Genetics, Genomic and Applied Microbiology, and Göttingen Genomics Laboratory, Germany
| | - Rolf Daniel
- Institute of Microbiology and Genetics, Genomic and Applied Microbiology, and Göttingen Genomics Laboratory, Germany
| | - Stefan Schulz
- Institute of Organic Chemistry, Technische Universität Braunschweig, Germany
| | - Thorsten Brinkhoff
- Institute for Chemistry and Biology of the Marine Environment, Oldenburg, Germany.
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46
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Willdigg JR, Helmann JD. Mini Review: Bacterial Membrane Composition and Its Modulation in Response to Stress. Front Mol Biosci 2021. [PMID: 34046426 DOI: 10.3389/fmolb.2021.634438/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
Antibiotics and other agents that perturb the synthesis or integrity of the bacterial cell envelope trigger compensatory stress responses. Focusing on Bacillus subtilis as a model system, this mini-review summarizes current views of membrane structure and insights into how cell envelope stress responses remodel and protect the membrane. Altering the composition and properties of the membrane and its associated proteome can protect cells against detergents, antimicrobial peptides, and pore-forming compounds while also, indirectly, contributing to resistance against compounds that affect cell wall synthesis. Many of these regulatory responses are broadly conserved, even where the details of regulation may differ, and can be important in the emergence of antibiotic resistance in clinical settings.
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Affiliation(s)
- Jessica R Willdigg
- Department of Microbiology, Cornell University, Ithaca, NY, United States
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, United States
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47
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Hoang CK, Nguyen VTH, Tran HTH, Le CH, Nguyen TD, Tran QH, Le HM, Tran HTN. Isolation and Structure Determination of PTP1B Inhibitor from Streptomyces sp. Strain TD-X10. APPL BIOCHEM MICRO+ 2021. [DOI: 10.1134/s0003683821010099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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48
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Alvares DS, Monti MR, Ruggiero Neto J, Wilke N. The antimicrobial peptide Polybia-MP1 differentiates membranes with the hopanoid, diplopterol from those with cholesterol. BBA ADVANCES 2021; 1:100002. [PMID: 37082019 PMCID: PMC10074923 DOI: 10.1016/j.bbadva.2021.100002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Polybia-MP1 is an antimicrobial peptide that shows a decreased activity in membranes with cholesterol (CHO). Since it is now accepted that hopanoids act as sterol-surrogates in some sterol-lacking bacteria, we here inquire about the impact of Polybia-MP1 on membranes containing the hopanoid diplopterol (DP) in comparison to membranes with CHO. We found that, despite the properties induced on lipid membranes by DP are similar to those induced by CHO, the effect of Polybia-MP1 on membranes with CHO or DP was significantly different. DP did not prevent dye release from LUVs, nor the insertion of Polybia-MP1 into monolayers, and peptide-membrane affinity was higher for those with DP than with CHO. Zeta potentials ( ζ ) for DP-containing LUVs showed a complex behavior at increasing peptide concentration. The effect of the peptide on membrane elasticity, investigated by nanotube retraction experiments, showed that peptide addition softened all membrane compositions, but membranes with DP got stiffer at long times. Considering this, and the ζ results, we propose that peptides accumulate at the interface adopting different arrangements, leading to a non-monotonic behavior. Possible correlations with cell membranes were inquired testing the antimicrobial activity of Polybia-MP1 against hopanoid-lacking bacteria pre-incubated with DP or CHO. The fraction of surviving cells was lower in cultures incubated with DP compared to those incubated with CHO. We propose that the higher activity of Polybia-MP1 against some bacteria compared to mammalian cells is not only related to membrane electrostatics, but also the composition of neutral lipids, particularly the hopanoids, could be important.
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49
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Janvier X, Alexandre S, Boukerb AM, Souak D, Maillot O, Barreau M, Gouriou F, Grillon C, Feuilloley MGJ, Groboillot A. Deleterious Effects of an Air Pollutant (NO 2) on a Selection of Commensal Skin Bacterial Strains, Potential Contributor to Dysbiosis? Front Microbiol 2020; 11:591839. [PMID: 33363523 PMCID: PMC7752777 DOI: 10.3389/fmicb.2020.591839] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/17/2020] [Indexed: 11/13/2022] Open
Abstract
The skin constitutes with its microbiota the first line of body defense against exogenous stress including air pollution. Especially in urban or sub-urban areas, it is continuously exposed to many environmental pollutants including gaseous nitrogen dioxide (gNO2). Nowadays, it is well established that air pollution has major effects on the human skin, inducing various diseases often associated with microbial dysbiosis. However, very few is known about the impact of pollutants on skin microbiota. In this study, a new approach was adopted, by considering the alteration of the cutaneous microbiota by air pollutants as an indirect action of the harmful molecules on the skin. The effects of gNO2 on this bacterial skin microbiota was investigated using a device developed to mimic the real-life contact of the gNO2 with bacteria on the surface of the skin. Five strains of human skin commensal bacteria were considered, namely Staphylococcus aureus MFP03, Staphylococcus epidermidis MFP04, Staphylococcus capitis MFP08, Pseudomonas fluorescens MFP05, and Corynebacterium tuberculostearicum CIP102622. Bacteria were exposed to high concentration of gNO2 (10 or 80 ppm) over a short period of 2 h inside the gas exposure device. The physiological, morphological, and molecular responses of the bacteria after the gas exposure were assessed and compared between the different strains and the two gNO2 concentrations. A highly significant deleterious effect of gNO2 was highlighted, particularly for S. capitis MFP08 and C. tuberculostearicum CIP102622, while S. aureus MFP03 seems to be the less sensitive strain. It appeared that the impact of this nitrosative stress differs according to the bacterial species and the gNO2 concentration. Thus the exposition to gNO2 as an air pollutant could contribute to dysbiosis, which would affect skin homeostasis. The response of the microbiota to the nitrosative stress could be involved in some pathologies such as atopic dermatitis.
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Affiliation(s)
- Xavier Janvier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen-Normandy, Normandy-University, Evreux, France
| | - Stéphane Alexandre
- Laboratory of Polymers, Biopolymers and Surfaces UMR CNRS 6270, University of Rouen-Normandy, Normandy-University, Mont-Saint-Aignan, France
| | - Amine M Boukerb
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen-Normandy, Normandy-University, Evreux, France
| | - Djouhar Souak
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen-Normandy, Normandy-University, Evreux, France
| | - Olivier Maillot
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen-Normandy, Normandy-University, Evreux, France
| | - Magalie Barreau
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen-Normandy, Normandy-University, Evreux, France
| | - Frantz Gouriou
- Aerothermic and Internal Combustion Engine Technological Research Center, Saint-Etienne-du-Rouvray, France
| | | | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen-Normandy, Normandy-University, Evreux, France
| | - Anne Groboillot
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University of Rouen-Normandy, Normandy-University, Evreux, France
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Zhang M, Zhang J, Wang Y, Wang J, Achimovich AM, Acton ST, Gahlmann A. Non-invasive single-cell morphometry in living bacterial biofilms. Nat Commun 2020; 11:6151. [PMID: 33262347 PMCID: PMC7708432 DOI: 10.1038/s41467-020-19866-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/26/2020] [Indexed: 01/08/2023] Open
Abstract
Fluorescence microscopy enables spatial and temporal measurements of live cells and cellular communities. However, this potential has not yet been fully realized for investigations of individual cell behaviors and phenotypic changes in dense, three-dimensional (3D) bacterial biofilms. Accurate cell detection and cellular shape measurement in densely packed biofilms are challenging because of the limited resolution and low signal to background ratios (SBRs) in fluorescence microscopy images. In this work, we present Bacterial Cell Morphometry 3D (BCM3D), an image analysis workflow that combines deep learning with mathematical image analysis to accurately segment and classify single bacterial cells in 3D fluorescence images. In BCM3D, deep convolutional neural networks (CNNs) are trained using simulated biofilm images with experimentally realistic SBRs, cell densities, labeling methods, and cell shapes. We systematically evaluate the segmentation accuracy of BCM3D using both simulated and experimental images. Compared to state-of-the-art bacterial cell segmentation approaches, BCM3D consistently achieves higher segmentation accuracy and further enables automated morphometric cell classifications in multi-population biofilms.
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Affiliation(s)
- Mingxing Zhang
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Ji Zhang
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Yibo Wang
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Jie Wang
- Department of Electrical & Computer Engineering, University of Virginia, Charlottesville, VA, USA
| | - Alecia M Achimovich
- Department of Molecular Physiology & Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Scott T Acton
- Department of Electrical & Computer Engineering, University of Virginia, Charlottesville, VA, USA
| | - Andreas Gahlmann
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA.
- Department of Molecular Physiology & Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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