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Nanninga N. Molecular Cytology of 'Little Animals': Personal Recollections of Escherichia coli (and Bacillus subtilis). Life (Basel) 2023; 13:1782. [PMID: 37629639 PMCID: PMC10455606 DOI: 10.3390/life13081782] [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: 07/18/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
This article relates personal recollections and starts with the origin of electron microscopy in the sixties of the previous century at the University of Amsterdam. Novel fixation and embedding techniques marked the discovery of the internal bacterial structures not visible by light microscopy. A special status became reserved for the freeze-fracture technique. By freeze-fracturing chemically fixed cells, it proved possible to examine the morphological effects of fixation. From there on, the focus switched from bacterial structure as such to their cell cycle. This invoked bacterial physiology and steady-state growth combined with electron microscopy. Electron-microscopic autoradiography with pulses of [3H] Dap revealed that segregation of replicating DNA cannot proceed according to a model of zonal growth (with envelope-attached DNA). This stimulated us to further investigate the sacculus, the peptidoglycan macromolecule. In particular, we focused on the involvement of penicillin-binding proteins such as PBP2 and PBP3, and their role in division. Adding aztreonam (an inhibitor of PBP3) blocked ongoing divisions but not the initiation of new ones. A PBP3-independent peptidoglycan synthesis (PIPS) appeared to precede a PBP3-dependent step. The possible chemical nature of PIPS is discussed.
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Affiliation(s)
- Nanne Nanninga
- Molecular Cytology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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2
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Abstract
This review focuses on nonlytic outer membrane vesicles (OMVs), a subtype of bacterial extracellular vesicles (BEVs) produced by Gram-negative organisms focusing on the mechanisms of their biogenesis, cargo, and function. Throughout, we highlight issues concerning the characterization of OMVs and distinguishing them from other types of BEVs. We also highlight the shortcomings of commonly used methodologies for the study of BEVs that impact the interpretation of their functionality and suggest solutions to standardize protocols for OMV studies.
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Affiliation(s)
| | - Simon R. Carding
- Quadram Institute Bioscience, Norwich, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
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3
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Asmar AT, Collet JF. Lpp, the Braun lipoprotein, turns 50—major achievements and remaining issues. FEMS Microbiol Lett 2018; 365:5071948. [DOI: 10.1093/femsle/fny199] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/10/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Abir T Asmar
- WELBIO, Université catholique de Louvain, avenue Hippocrate 75, Brussels 1200, Belgium
- De Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, Brussels 1200, Belgium
| | - Jean-François Collet
- WELBIO, Université catholique de Louvain, avenue Hippocrate 75, Brussels 1200, Belgium
- De Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, Brussels 1200, Belgium
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4
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Kowata H, Tochigi S, Kusano T, Kojima S. Quantitative measurement of the outer membrane permeability in Escherichia coli lpp and tol-pal mutants defines the significance of Tol-Pal function for maintaining drug resistance. J Antibiot (Tokyo) 2016; 69:863-870. [PMID: 27168313 DOI: 10.1038/ja.2016.50] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/16/2016] [Accepted: 04/05/2016] [Indexed: 02/05/2023]
Abstract
Ensuring the stability of the outer membrane permeability barrier is crucial for maintaining drug resistance in Gram-negative bacteria. Lpp protein and Tol-Pal complex are responsible for this function and are widely distributed among Gram-negative bacteria. Thus, these proteins are potential targets to permeabilize the outer membrane barrier. Although deleting these proteins is known to impair the outer membrane stability, the effect of the deletion on the outer membrane barrier property and on the drug resistance has not been fully characterized and evaluated in a quantitative manner. Here, we determined the outer membrane permeability of Escherichia coli Δlpp and Δtol-pal mutants by the assay using intact cells and liposomes reconstituted with the outer membrane proteins. We determined that there was 3- to 5-fold increase of the permeability in Δtol-pal mutants, but not in Δlpp mutant, compared with that in the parental strain. The permeability increase in Δtol-pal mutants occurred without affecting the function of outer membrane diffusion channels, and was most pronounced in the cells at exponential growth phase. The impact of tol-pal deletion on the drug resistance was revealed to be almost comparable with that of deletion of acrAB, a major multidrug efflux transporter of E. coli that makes a predominant contribution to drug resistance. Our observations highlight the importance of Tol-Pal as a possible target to combat multidrug-resistant Gram-negative bacteria.
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Affiliation(s)
- Hikaru Kowata
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Saeko Tochigi
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Tomonobu Kusano
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Seiji Kojima
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
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5
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Buddelmeijer N. The molecular mechanism of bacterial lipoprotein modification—How, when and why? FEMS Microbiol Rev 2015; 39:246-61. [DOI: 10.1093/femsre/fuu006] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Salinity-dependent impacts of ProQ, Prc, and Spr deficiencies on Escherichia coli cell structure. J Bacteriol 2014; 196:1286-96. [PMID: 24443528 DOI: 10.1128/jb.00827-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
ProQ is a cytoplasmic protein with RNA chaperone activities that reside in FinO- and Hfq-like domains. Lesions at proQ decrease the level of the osmoregulatory glycine betaine transporter ProP. Lesions at proQ eliminated ProQ and Prc, the periplasmic protease encoded by the downstream gene prc. They dramatically slowed the growth of Escherichia coli populations and altered the morphologies of E. coli cells in high-salinity medium. ProQ and Prc deficiencies were associated with different phenotypes. ProQ-deficient bacteria were elongated unless glycine betaine was provided. High-salinity cultures of Prc-deficient bacteria included spherical cells with an enlarged periplasm and an eccentric nucleoid. The nucleoid-containing compartment was bounded by the cytoplasmic membrane and peptidoglycan. This phenotype was not evident in bacteria cultivated at low or moderate salinity, nor was it associated with murein lipoprotein (Lpp) deficiency, and it differed from those elicited by the MreB inhibitor A-22 or the FtsI inhibitor aztreonam at low or high salinity. It was suppressed by deletion of spr, which encodes one of three murein hydrolases that are redundantly essential for enlargement of the murein sacculus. Prc deficiency may alter bacterial morphology by impairing control of Spr activity at high salinity. ProQ and Prc deficiencies lowered the ProP activity of bacteria cultivated at moderate salinity by approximately 70% and 30%, respectively, but did not affect other osmoregulatory functions. The effects of ProQ and Prc deficiencies on ProP activity are indirect, reflecting their roles in the maintenance of cell structure.
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7
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Schwechheimer C, Sullivan CJ, Kuehn MJ. Envelope control of outer membrane vesicle production in Gram-negative bacteria. Biochemistry 2013; 52:3031-40. [PMID: 23521754 DOI: 10.1021/bi400164t] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
All Gram-negative bacteria studied to date have been shown to produce outer membrane vesicles (OMVs), which are budded, released spheres of outer membrane with periplasmic content. OMVs have been implicated in the delivery of virulence factors in pathogenesis. However, OMVs also benefit nonpathogenic species by delivering degradative enzymes to defend an ecological niche against competing bacterial species, and they can serve as an envelope stress response. Despite these important roles, very little is known about the mechanism of production of OMVs. Here we review the advantage of vesiculation, particularly in a nonpathogenic context, as well as the hurdles that have to be overcome in Gram-negative envelope architecture before a vesicle can form and bud. Lastly, we address the question of whether OMV production is a stochastic or regulated process.
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Affiliation(s)
- Carmen Schwechheimer
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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Lahiri A, Ananthalakshmi TK, Nagarajan AG, Ray S, Chakravortty D. TolA mediates the differential detergent resistance pattern between the Salmonella enterica subsp. enterica serovars Typhi and Typhimurium. MICROBIOLOGY (READING, ENGLAND) 2011; 157:1402-1415. [PMID: 21252278 DOI: 10.1099/mic.0.046565-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
The tol-pal genes are essential for maintaining the outer membrane integrity and detergent resistance in various Gram-negative bacteria, including Salmonella. The role of TolA has been well established for the bile resistance of Salmonella enterica subsp. enterica serovar Typhimurium. We compared the bile resistance pattern between the S. enterica serovars Typhi and Typhimurium and observed that Typhi is more resistant to bile-mediated damage. A closer look revealed a significant difference in the TolA sequence between the two serovars which contributes to the differential detergent resistance. The tolA knockout of both the serovars behaves completely differently in terms of membrane organization and morphology. The role of the Pal proteins and difference in LPS organization between the two serovars were verified and were found to have no direct connection with the altered bile resistance. In normal Luria broth (LB), S. Typhi ΔtolA is filamentous while S. Typhimurium ΔtolA grows as single cells, similar to the wild-type. In low osmolarity LB, however, S. Typhimurium ΔtolA started chaining and S. Typhi ΔtolA showed no growth. Further investigation revealed that the chaining phenomenon observed was the result of failure of the outer membrane to separate in the dividing cells. Taken together, the results substantiate the evolution of a shorter TolA in S. Typhi to counteract high bile concentrations, at the cost of lower osmotic tolerance.
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Affiliation(s)
- Amit Lahiri
- Centre for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - T K Ananthalakshmi
- Centre for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Arvindhan G Nagarajan
- Centre for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Seemun Ray
- Centre for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Dipshikha Chakravortty
- Centre for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
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9
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Den Blaauwen T, de Pedro MA, Nguyen-Distèche M, Ayala JA. Morphogenesis of rod-shaped sacculi. FEMS Microbiol Rev 2008; 32:321-44. [DOI: 10.1111/j.1574-6976.2007.00090.x] [Citation(s) in RCA: 232] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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10
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Hongsthong A, Sirijuntarut M, Prommeenate P, Thammathorn S, Bunnag B, Cheevadhanarak S, Tanticharoen M. Revealing differentially expressed proteins in two morphological forms of Spirulina platensis by proteomic analysis. Mol Biotechnol 2007; 36:123-30. [PMID: 17914191 DOI: 10.1007/s12033-007-0013-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 10/23/2022]
Abstract
Spirulina is distinguished from other cyanobacteria by its spiral morphology; however, this cyanobacterium has frequently been observed with a linear morphology in laboratory and industrial conditions. In our laboratory conditions, the simultaneously presence of the linear and spiral forms has also been observed. In the present study, the two forms of S. platensis C1 were separated and grown as axenic cultures in order to study the proteins that were differentially expressed in the soluble and insoluble protein fractions of the spiral and the linear forms. Two dimensional-differential gel electrophoresis (2D-DIGE) was performed to separate differentially expressed proteins that were subsequently identified by mass spectrometry. The differentially expressed proteins suggested two points. First, the morphological change is possibly induced by various environmental stresses such as oxygen level, carbon dioxide level, nutrient availability, and light. Second, the change of cell-shape might be a result of the change in a cell shape determination mechanism. Thus, this study is the first to show evidence at the protein level that may explain this morphological transformation in Spirulina.
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Affiliation(s)
- Apiradee Hongsthong
- National Center for Genetic Engineering and Biotechnology, 83 Moo8, Thakham, Bangkhuntien, Bangkok 10150, Thailand.
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11
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Gerding MA, Ogata Y, Pecora ND, Niki H, de Boer PAJ. The trans-envelope Tol-Pal complex is part of the cell division machinery and required for proper outer-membrane invagination during cell constriction in E. coli. Mol Microbiol 2007; 63:1008-25. [PMID: 17233825 PMCID: PMC4428343 DOI: 10.1111/j.1365-2958.2006.05571.x] [Citation(s) in RCA: 278] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fission of bacterial cells involves the co-ordinated invagination of the envelope layers. Invagination of the cytoplasmic membrane (IM) and peptidoglycan (PG) layer is likely driven by the septal ring organelle. Invagination of the outer membrane (OM) in Gram-negative species is thought to occur passively via its tethering to the underlying PG layer with generally distributed PG-binding OM (lipo)proteins. The Tol-Pal system is energized by proton motive force and is well conserved in Gram-negative bacteria. It consists of five proteins that can connect the OM to both the PG and IM layers via protein-PG and protein-protein interactions. Although the system is needed to maintain full OM integrity, and for class A colicins and filamentous phages to enter cells, its precise role has remained unclear. We show that all five components accumulate at constriction sites in Escherichia coli and that mutants lacking an intact system suffer delayed OM invagination and contain large OM blebs at constriction sites and cell poles. We propose that Tol-Pal constitutes a dynamic subcomplex of the division apparatus in Gram-negative bacteria that consumes energy to establish transient trans-envelope connections at/near the septal ring to draw the OM onto the invaginating PG and IM layers during constriction.
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Affiliation(s)
- Matthew A. Gerding
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Yasuyuki Ogata
- Radioisotope Center, Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Nicole D. Pecora
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Hironori Niki
- Radioisotope Center, Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, Japan
- Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Piet A. J. de Boer
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
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12
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Ghosh AS, Melquist AL, Young KD. Loss of O-antigen increases cell shape abnormalities in penicillin-binding protein mutants of Escherichia coli. FEMS Microbiol Lett 2006; 263:252-7. [PMID: 16978365 PMCID: PMC3646521 DOI: 10.1111/j.1574-6968.2006.00429.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Escherichia coli mutants lacking multiple penicillin-binding proteins (PBPs) produce aberrantly shaped cells. However, most of these experiments have been performed in E. coli K12 strains, which do not attach a complete O-antigen to their outer membrane lipopolysaccharide. We constructed mutants in different genetic backgrounds and found that the frequency of morphological deformities was higher in strains lacking the O-antigen. Also, complementing O-negative mutants with a heterologous O-antigen from Klebsiella returned a substantial fraction of misshapen cells to a normal morphology. Thus, the O-antigen contributes to cell shape in E. coli, perhaps by reducing the number of ectopic poles, which may be the proximal cause of shape abnormalities.
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Affiliation(s)
- Anindya S. Ghosh
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, WB, India
| | - Amy L. Melquist
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Kevin D. Young
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
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13
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Abstract
In free-living eubacteria an external shell of peptidoglycan opposes internal hydrostatic pressure and prevents membrane rupture and death. At the same time, this wall imposes on each cell a shape. Because shape is both stable and heritable, as is the ability of many organisms to execute defined morphological transformations, cells must actively choose from among a large repertoire of available shapes. How they do so has been debated for decades, but recently experiment has begun to catch up with theory. Two discoveries are particularly informative. First, specific protein assemblies, nucleated by FtsZ, MreB or Mbl, appear to act as internal scaffolds that influence cell shape, perhaps by correctly localizing synthetic enzymes. Second, defects in cell shape are correlated with the presence of inappropriately placed, metabolically inert patches of peptidoglycan. When combined with what we know about mutants affecting cellular morphology, these observations suggest that bacteria may fabricate specific shapes by directing the synthesis of two kinds of cell wall: a long-lived, rigid framework that defines overall topology, and a metabolically plastic peptidoglycan whose shape is directed by internal scaffolds.
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Affiliation(s)
- Kevin D Young
- Department of Microbiology and Immunology, University of North Dakota School of Medicine, Grand Forks 58202-9037, USA.
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de Kort G, van der Bent-Klootwijk P, van de Klundert JA. Immuno-detection of the virulence determinant OmpX at the cell surface of Enterobacter cloacae. FEMS Microbiol Lett 1998; 158:115-20. [PMID: 9453162 DOI: 10.1111/j.1574-6968.1998.tb12809.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A model for the topology of the Enterobacter cloacae outer membrane protein OmpX has been proposed, based on the primary sequence and on analogy to homologous proteins. According to this model the membrane embedded part of the protein consists of eight antiparallel beta-strands. Four random coil loops are located at the bacterial surface and three beta-turns at the periplasmic side of the membrane. Antibodies were raised against synthetic peptides representing five OmpX domains, four of which are putative peripheral and one located in the membrane. The accessibilities of OmpX to these antibodies were tested in intact cells by immuno-gold electron microscopy. This study showed that OmpX is indeed an outer membrane protein, the N-proximal loop of which forms an IgG-accessible epitope at the cell surface.
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Affiliation(s)
- G de Kort
- Department of Medical Microbiology, Leiden University Medical Center, The Netherlands
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Braun V, Wu H. Chapter 14 Lipoproteins, structure, function, biosynthesis and model for protein export. BACTERIAL CELL WALL 1994. [DOI: 10.1016/s0167-7306(08)60417-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Affiliation(s)
- B E Anderson
- Division of Viral and Rickettsial Diseases, United States Department of Health and Human Services, Centers for Disease Control, Atlanta, Georgia 30333
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de Jonge BL, Wientjes FB, Jurida I, Driehuis F, Wouters JT, Nanninga N. Peptidoglycan synthesis during the cell cycle of Escherichia coli: composition and mode of insertion. J Bacteriol 1989; 171:5783-94. [PMID: 2681142 PMCID: PMC210437 DOI: 10.1128/jb.171.11.5783-5794.1989] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The composition and the mode of insertion of peptidoglycan synthesized during the cell cycle of Escherichia coli were determined. This was carried out on peptidoglycan that was periodically pulse-labeled in synchronously growing cultures. The chemical composition of the pulse-labeled (newly synthesized) peptidoglycan remained constant throughout the cell cycle, as judged from high-pressure liquid chromatography analysis of the muropeptide composition. The mode of insertion was deduced from the acceptor-donor radioactivity ratio in the bis-disaccharide tetratetra compound. The ratio was low in elongating cells and high in constricting cells. This indicates that during elongation, peptidoglycan was inserted as single strands, whereas during constriction, a multistranded (or sequential single-stranded) insertion occurred. Experiments with an ftsA division mutant suggested that the composition and mode of insertion of newly synthesized peptidoglycan remained the same throughout the constriction process. Our results imply that the changed mode of insertion rather than the chemical structure of the peptidoglycan might be responsible for the transition from cell elongation to polar cap formation.
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Affiliation(s)
- B L de Jonge
- Department of Microbiology, University of Amsterdam, The Netherlands
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Henriksen AZ, Maeland JA, Brakstad OG. Monoclonal antibodies against three different enterobacterial outer membrane proteins. Characterization, cross-reactivity, and binding to bacteria. APMIS 1989; 97:559-68. [PMID: 2660858 DOI: 10.1111/j.1699-0463.1989.tb00831.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BALB/c mice were immunized with whole-cells of Escherichia coli 055:B5 or Proteus mirabilis NCTC 60 to produce broadly cross-reacting monoclonal antibodies (MAbs) against outer membrane (OM) proteins. A total of 10 anti-OM MAbs of the IgG class were selected. These included 5 MAbs against the heat-modifiable (Hm) protein, 3 against the peptidoglycan-associated lipoprotein (PALp), and 2 against Braun's lipoprotein (BLp). Based on competition ELISA, the MAbs defined 2 Hm protein binding sites (Hm I and Hm II), 2 PALp sites (PALp I and PALp II), and one BLp site (BLp I). The MAbs showed broad cross-reactivity against 74 strains of 10 different genera of the Enterobacteriaceae. Non-cross-reacting enteric bacilli occurred only among bacteria of the genera Salmonella, Proteus, and Providentia. The results revealed that Proteus and Providentia strains differed from other enteric bacilli with regard to BLp synthesis or specificity. A panel of 30 non-enteric Gram-negative bacteria did not cross-react. Testing of MAb binding to bacteria showed that a part of the BLp I, PALp I, and PALp II sites was immunoaccessible in intact homologous bacteria, and that the Hm I and Hm II epitopes were inaccessible. The MAbs should facilitate studies of structure and immunobiological function of enterobacterial OM proteins and should have a potential as immunodiagnostic reagents.
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Affiliation(s)
- A Z Henriksen
- Department of Microbiology, Faculty of Medicine, University of Trondheim, Norway
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