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Safronova N, Junghans L, Saenz JP. Temperature change elicits lipidome adaptation in the simple organisms Mycoplasma mycoides and JCVI-syn3B. Cell Rep 2024; 43:114435. [PMID: 38985673 DOI: 10.1016/j.celrep.2024.114435] [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: 11/27/2023] [Revised: 04/05/2024] [Accepted: 06/19/2024] [Indexed: 07/12/2024] Open
Abstract
Cell membranes mediate interactions between life and its environment, with lipids determining their properties. Understanding how cells adjust their lipidomes to tune membrane properties is crucial yet poorly defined due to the complexity of most organisms. We used quantitative shotgun lipidomics to study temperature adaptation in the simple organism Mycoplasma mycoides and the minimal cell JCVI-syn3B. We show that lipid abundances follow a universal logarithmic distribution across eukaryotes and bacteria, with comparable degrees of lipid remodeling for adaptation regardless of lipidomic or organismal complexity. Lipid features analysis demonstrates head-group-specific acyl chain remodeling as characteristic of lipidome adaptation; its deficiency in Syn3B is associated with impaired homeoviscous adaptation. Temporal analysis reveals a two-stage cold adaptation process: swift cholesterol and cardiolipin shifts followed by gradual acyl chain modifications. This work provides an in-depth analysis of lipidome adaptation in minimal cells, laying a foundation to probe the design principles of living membranes.
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Affiliation(s)
- Nataliya Safronova
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, 01062 Dresden, Germany
| | - Lisa Junghans
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, 01062 Dresden, Germany
| | - James P Saenz
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, 01062 Dresden, Germany; Faculty of Medicine, Technische Universität Dresden, 01062 Dresden, Germany.
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2
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Chakraborty J, Poddar S, Dutta S, Bahulekar V, Harne S, Srinivasan R, Gayathri P. Dynamics of interdomain rotation facilitates FtsZ filament assembly. J Biol Chem 2024; 300:107336. [PMID: 38718863 PMCID: PMC11157280 DOI: 10.1016/j.jbc.2024.107336] [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: 03/09/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/31/2024] Open
Abstract
FtsZ, the tubulin homolog essential for bacterial cell division, assembles as the Z-ring at the division site, and directs peptidoglycan synthesis by treadmilling. It is unclear how FtsZ achieves kinetic polarity that drives treadmilling. To obtain insights into fundamental features of FtsZ assembly dynamics independent of peptidoglycan synthesis, we carried out structural and biochemical characterization of FtsZ from the cell wall-less bacteria, Spiroplasma melliferum (SmFtsZ). Interestingly the structures of SmFtsZ, bound to GDP and GMPPNP respectively, were captured as domain swapped dimers. SmFtsZ was found to be a slower GTPase with a higher critical concentration (CC) compared to Escherichia coli FtsZ (EcFtsZ). In FtsZs, a conformational switch from R-state (close) to T-state (open) favors polymerization. We identified that Phe224, located at the interdomain cleft of SmFtsZ, is crucial for R- to T-state transition. SmFtsZF224M exhibited higher GTPase activity and lower CC, whereas the corresponding EcFtsZM225F resulted in cell division defects in E. coli. Our results demonstrate that relative rotation of the domains is a rate-limiting step of polymerization. Our structural analysis suggests that the rotation is plausibly triggered upon addition of a GTP-bound monomer to the filament through interaction of the preformed N-terminal domain (NTD). Hence, addition of monomers to the NTD-exposed end of filament is slower in comparison to the C-terminal domain (CTD) end, thus explaining kinetic polarity. In summary, the study highlights the importance of interdomain interactions and conformational changes in regulating FtsZ assembly dynamics.
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Affiliation(s)
- Joyeeta Chakraborty
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Sakshi Poddar
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India; Homi Bhabha National Institutes (HBNI), Training School Complex, Mumbai, India
| | - Soumyajit Dutta
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Vaishnavi Bahulekar
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Shrikant Harne
- Biology Division, Indian Institute of Science Education and Research, Pune, India
| | - Ramanujam Srinivasan
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India; Homi Bhabha National Institutes (HBNI), Training School Complex, Mumbai, India
| | - Pananghat Gayathri
- Biology Division, Indian Institute of Science Education and Research, Pune, India.
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3
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Sarkar P, Lin CY, Buritica JR, Killiny N, Levy A. Crossing the Gateless Barriers: Factors Involved in the Movement of Circulative Bacteria Within Their Insect Vectors. PHYTOPATHOLOGY 2023; 113:1805-1816. [PMID: 37160668 DOI: 10.1094/phyto-07-22-0249-ia] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Plant bacterial pathogens transmitted by hemipteran vectors pose a large threat to the agricultural industry worldwide. Although virus-vector relationships have been widely investigated, a significant gap exists in our understanding of the molecular interactions between circulative bacteria and their insect vectors, mainly leafhoppers and psyllids. In this review, we will describe how these bacterial pathogens adhere, invade, and proliferate inside their insect vectors. We will also highlight the different transmission routes and molecular factors of phloem-limited bacteria that maintain an effective relationship with the insect host. Understanding the pathogen-vector relationship at the molecular level will help in the management of vector-borne bacterial diseases.
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Affiliation(s)
- Poulami Sarkar
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
| | - Chun-Yi Lin
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
| | - Jacobo Robledo Buritica
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - Nabil Killiny
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - Amit Levy
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
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Gaurivaud P, Tardy F. The Mycoplasma spp. ‘Releasome’: A New Concept for a Long-Known Phenomenon. Front Microbiol 2022; 13:853440. [PMID: 35495700 PMCID: PMC9051441 DOI: 10.3389/fmicb.2022.853440] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
The bacterial secretome comprises polypeptides expressed at the cell surface or released into the extracellular environment as well as the corresponding secretion machineries. Despite their reduced coding capacities, Mycoplasma spp. are able to produce and release several components into their environment, including polypeptides, exopolysaccharides and extracellular vesicles. Technical difficulties in purifying these elements from the complex broth media used to grow mycoplasmas have recently been overcome by optimizing growth conditions and switching to chemically defined culture media. However, the secretion pathways responsible for the release of these structurally varied elements are still poorly described in mycoplasmas. We propose the use of the term ‘releasome,’ instead of secretome, to refer to molecules released by mycoplasmas into their environment. The aim of this review is to more precisely delineate the elements that should be considered part of the mycoplasmal releasome and their role in the interplay of mycoplasmas with host cells and tissues.
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Deeney AS, Collins R, Ridley AM. Identification of Mycoplasma species and related organisms from ruminants in England and Wales during 2005-2019. BMC Vet Res 2021; 17:325. [PMID: 34641885 PMCID: PMC8513359 DOI: 10.1186/s12917-021-03037-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/30/2021] [Indexed: 11/10/2022] Open
Abstract
Background Mycoplasma species have been associated with economically important diseases affecting ruminants worldwide and include contagious bovine pleuropneumonia (CBPP), contagious caprine pleuropneumonia (CCPP) and contagious agalactia, listed by the World Organisation for Animal Health (OIE). The Mycoplasma Team at the Animal and Plant Health Agency provides an identification service for Mycoplasma and Ureaplasma species of veterinary importance to the United Kingdom (UK), supporting the detection of new and emerging pathogens, as well as contributing to the surveillance of endemic, and the OIE listed diseases exotic to the UK. Mycoplasma and other Mollicutes species were identified from diagnostic samples from farmed ruminants in England and Wales using a combination of culture and 16S rRNA gene-based PCR-denaturing gradient gel electrophoresis, submitted between 2005 and 2019. Results A total of 5578 mollicutes identifications, which include mycoplasmas and the related acholeoplasmas and ureaplasmas, were made from farmed ruminant animals during the study period. Throughout the study period, the pathogen Mycoplasma bovis was consistently the most frequently identified species, accounting for 1411 (32%) of 4447 molecular identifications in cattle, primarily detected in the lungs of pneumonic calves, followed by joints and milk of cattle showing signs of arthritis and mastitis, respectively. M. bovirhinis, M. alkalescens, M. dispar, M. arginini and Ureaplasma diversum, were also common. Mixed species, principally M. bovis with M. alkalescens, M. arginini or M. bovirhinis were also prevalent, particularly from respiratory samples. The non-cultivable blood-borne haemoplasmas Candidatus ‘Mycoplasma haemobos’ and Mycoplasma wenyonii were identified from cattle, with the latter species most often associated with milk-drop. M. ovipneumoniae was the predominant species identified from sheep and goats experiencing respiratory disease, while M. conjunctivae preponderated in ocular samples. The UK remains free of the ruminant mycoplasmas listed by OIE. Conclusions The continued high prevalence of M. bovis identifications confirms its ongoing dominance and importance as a significant pathogen of cattle in England and Wales, particularly in association with respiratory disease. M. ovipneumoniae has seen a general increase in prevalence in recent years, notably in coughing lambs and should therefore be considered as a primary differential diagnosis of respiratory disease in small ruminants.
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Affiliation(s)
- Alannah S Deeney
- Mycoplasma Team, Department of Bacteriology, Animal and Plant Health Agency, Weybridge, Surrey, UK.
| | - Rachael Collins
- Animal and Plant Health Agency Veterinary Investigation Centre, Starcross, Exeter, UK
| | - Anne M Ridley
- Mycoplasma Team, Department of Bacteriology, Animal and Plant Health Agency, Weybridge, Surrey, UK
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Harne S, Gayathri P, Béven L. Exploring Spiroplasma Biology: Opportunities and Challenges. Front Microbiol 2020; 11:589279. [PMID: 33193251 PMCID: PMC7609405 DOI: 10.3389/fmicb.2020.589279] [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: 07/30/2020] [Accepted: 09/28/2020] [Indexed: 11/13/2022] Open
Abstract
Spiroplasmas are cell-wall-deficient helical bacteria belonging to the class Mollicutes. Their ability to maintain a helical shape in the absence of cell wall and their motility in the absence of external appendages have attracted attention from the scientific community for a long time. In this review we compare and contrast motility, shape determination and cytokinesis mechanisms of Spiroplasma with those of other Mollicutes and cell-walled bacteria. The current models for rod-shape determination and cytokinesis in cell-walled bacteria propose a prominent role for the cell wall synthesis machinery. These models also involve the cooperation of the actin-like protein MreB and FtsZ, the bacterial homolog of tubulin. However the exact role of the cytoskeletal proteins is still under much debate. Spiroplasma possess MreBs, exhibit a rod-shape dependent helical morphology, and divide by an FtsZ-dependent mechanism. Hence, spiroplasmas represent model organisms for deciphering the roles of MreBs and FtsZ in fundamental mechanisms of non-spherical shape determination and cytokinesis in bacteria, in the absence of a cell wall. Identification of components implicated in these processes and deciphering their functions would require genetic experiments. Challenges in genetic manipulations in spiroplasmas are a major bottleneck in understanding their biology. We discuss advancements in genome sequencing, gene editing technologies, super-resolution microscopy and electron cryomicroscopy and tomography, which can be employed for addressing long-standing questions related to Spiroplasma biology.
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Affiliation(s)
- Shrikant Harne
- Indian Institute of Science Education and Research, Pune, India
| | | | - Laure Béven
- INRAE, UMR 1332, Biologie du Fruit et Pathologie, University of Bordeaux, Bordeaux, France
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Ruiz N. A bird's eye view of the bacterial landscape. Methods Mol Biol 2013; 966:1-14. [PMID: 23299725 DOI: 10.1007/978-1-62703-245-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Bacteria interact with the environment through their cell surface. Activities as diverse as attaching to a catheter, crawling on a surface, swimming through a pond, or being preyed on by a bacteriophage depend on the composition and structure of the cell surface. The cell surface must also protect bacteria from harmful chemicals present in the environment while allowing the intake of nutrients and excretion of toxic molecules. Bacteria have evolved four main types of bacterial cell surfaces to accomplish these functions: those of the typical gram-negative and gram-positive bacteria, and those of the Actinobacteria and Mollicutes. So few types seems remarkable since bacteria are very diverse and abundant, and they can live in many different environments. However, each species has tweaked these stereotypical bacterial surfaces to best fit its needs. The result is an amazing diversity of the bacterial landscape, most of which remains unexplored. Here I give an overview of the main features of the bacterial cell surface and highlight how advances in methodology have moved forward this field of study.
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Affiliation(s)
- Natividad Ruiz
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.
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Trachtenberg S, Dorward LM, Speransky VV, Jaffe H, Andrews SB, Leapman RD. Structure of the cytoskeleton of Spiroplasma melliferum BC3 and its interactions with the cell membrane. J Mol Biol 2008; 378:778-89. [PMID: 18400234 DOI: 10.1016/j.jmb.2008.02.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 02/04/2008] [Accepted: 02/12/2008] [Indexed: 10/22/2022]
Abstract
Spiroplasma melliferum is a wall-less bacterium with dynamic helical symmetry. Taking advantage of the simplicity of this primitive lifeform, we have used structural (electron tomography and freeze fracture of whole cells; cryoelectron tomography and diffraction analysis of isolated cytoskeletons) and proteomic approaches to elucidate the basic organizing principles of its minimal yet functional cytoskeleton. From among approximately 30 Spiroplasma proteins present in a highly purified cytoskeletal fraction, we identify three major putative structural proteins: Fib, MreB, and elongation factor Tu. Fib assembles into a single flattened ribbon that follows the shortest helical line just under the plasma membrane and acts as a linear motor, whereas MreB is present as a matching array of membrane-associated fibrils parallel and associated with the motor. We also identify a prominent previously unknown filamentous network that occupies much of the cytoplasm and appears to cross-link the ribosomes. The abundant potentially filament-forming protein elongation factor Tu may be a component of this network, but the tomography data are most consistent with DNA as the core component. The results provide new information on the minimal organization necessary to support the scaffolding and motile functions of a minimal cytoskeleton.
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Affiliation(s)
- Shlomo Trachtenberg
- Department of Membrane and Ultrastructure Research, The Hebrew University-Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel.
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9
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Wróblewski H, Johansson KE, Hjérten S. Purification and characterization of spiralin, the main protein of the Spiroplasma citri membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 465:275-89. [PMID: 16250340 DOI: 10.1016/0005-2736(77)90079-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The membrane proteins from Spiroplasma citri have been resolved into 16 components by SDS-polyacrylamide gel electrophoresis. By this technique it was also shown that the molecular weights of these proteins ranged from 13000 to 160 000. One of the proteins, which had an apparent molecular weight of 26 000 was the most abundant and represented more than 22% of total membrane protein. We have designated this protein spiralin. None of the proteins contained carbohydrate. Spiralin has been isolated by a procedure which involves removal of some membrane proteins with the neutral detergent Tween 20, selective solubilization of the Tween residue in DOC and fractionation of the DOC-soluble material by agarose-suspension electrophoresis. The homogeneity of spiralin was demonstrated by analytical polyacrylamide gel electrophoresis under different conditions and by crossed immunoelectrophoresis. Spiralin appeared to bind less DOC than the other membrane proteins of S. citri. This observation does not imply, however, that the binding of DOC to spiralin is weak. Spiralin was neither soluble in detergent-free buffers nor in Tween 20, which indicated that it is an intrinsic membrane protein. The amino-acid composition of spiralin was quite different from that of the membrane. Spiralin lacked methionine, histidine and tryptophan, and had a low content of glycine, leucine, tyrosine and phenylalanine, but a high content of threonine, alanine and valine.
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Affiliation(s)
- H Wróblewski
- Laboratoire de Biologie Cellulaire, Faculté des Sciences Biologiques, Complexe de Beaulieu, B.P. 25 A, 35031 Rennes, France
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Nunan LM, Lightner DV, Oduori MA, Gasparich GE. Spiroplasma penaei sp. nov., associated with mortalities in Penaeus vannamei, Pacific white shrimp. Int J Syst Evol Microbiol 2005; 55:2317-2322. [PMID: 16280489 DOI: 10.1099/ijs.0.63555-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A new bacterial strain, designated SHRIMPT, isolated from the haemolymph of the Pacific white shrimp, Penaeus vannamei, was serologically distinct from other spiroplasmas. Cells of this strain were helical in form and variable in length. Examination by electron microscopy revealed wall-less cells delineated by a single cytoplasmic membrane. The organisms grew well in M1D media supplemented with 2 % NaCl. Strain SHRIMPT grew at temperatures of 20–37 °C, with optimum growth occurring at 28 °C. The strain catabolized glucose and hydrolysed arginine, but did not hydrolyse urea. The G+C content of the DNA was 29±1 mol%. Strain SHRIMPT (=ATCC BAA-1082T=CAIM 1252T) is designated the type strain of a novel species, Spiroplasma penaei sp. nov., which represents a new subgroup (I-9) of the group I spiroplasmas.
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Affiliation(s)
- Linda M Nunan
- Department of Veterinary Sciences and Microbiology, University of Arizona, Tucson, AZ 85721, USA
| | - Donald V Lightner
- Department of Veterinary Sciences and Microbiology, University of Arizona, Tucson, AZ 85721, USA
| | - Marietta A Oduori
- Department of Biological Sciences, Towson University, Towson, MD 21252, USA
| | - Gail E Gasparich
- Department of Biological Sciences, Towson University, Towson, MD 21252, USA
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Miyata M, Petersen JD. Spike structure at the interface between gliding Mycoplasma mobile cells and glass surfaces visualized by rapid-freeze-and-fracture electron microscopy. J Bacteriol 2004; 186:4382-6. [PMID: 15205441 PMCID: PMC421615 DOI: 10.1128/jb.186.13.4382-4386.2004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycoplasma mobile is a flask-shaped bacteria that binds to a substrate and glides towards its tapered end, the so-called "head-like protrusion," by an unknown mechanism. To search for cellular structures underlying this motility, the cell-substrate interface of actively gliding cells was visualized by rapid-freeze-and-freeze-fracture rotary-shadow electron microscopy. Novel structures, called "spikes," were observed to protrude from the cell membrane and attach to the glass surface at their distal end. The spikes were on average 50 nm in length and 4 nm in diameter, most abundant around the head, and not observed in a nonbinding mutant. The spikes may be involved in the mechanism of binding, gliding, or both.
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Affiliation(s)
- Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan.
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12
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Andreev J, Borovsky Z, Rosenshine I, Rottem S. Invasion of HeLa cells by Mycoplasma penetrans and the induction of tyrosine phosphorylation of a 145-kDa host cell protein. FEMS Microbiol Lett 1995; 132:189-94. [PMID: 7590171 DOI: 10.1111/j.1574-6968.1995.tb07832.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The ability of Mycoplasma penetrans to invade eukaryotic cells was studied using a HeLa cell line. The bactericidal antibiotic, gentamicin, in combination with low concentrations of Triton X-100, was utilized to kill mycoplasmas that had not entered the cells, allowing the quantitation of internalized organisms. The intracellular location of the mycoplasma was also documented by transmission electron microscopy. The actin polymerization inhibitor cytochalasin-D markedly inhibited the internalization process, whereas the tyrosine phosphorylation inhibitors, staurosporin and genistein had only a slight effect. As against the invasion of enteropathogenic Escherichia coli which depends on tyrosine phosphorylation of a 90-kDa (Hp90) HeLa cell protein, internalization of M. penetrans by HeLa cells was independent of the phosphorylation of Hp90. Nonetheless, tyrosine phosphorylation of a 145-kDa HeLa cell protein was found to be associated with the interaction of M. penetrans with HeLa cells.
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Affiliation(s)
- J Andreev
- Department of Membrane, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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13
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Abstract
Of the 51 polypeptides detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the plasma membrane of the helical mollicute Spiroplasma melliferum, 21 are acylated, predominantly with myristic (14:0) and palmitic (16:0) chains. This is notably the case for spiralin, the major membrane protein of this bacterium, which contains an average of 0.7 acyl chains per polypeptide, attached very probably by ester bonds to alcohol amino acids. The amphiphilicity of spiralin was demonstrated by the behavior of the protein in charge-shift electrophoresis, its incorporation into liposomes, and its ability to form in the absence of lipids and detergents, globular protein micelles (diameter, approximately 15 nm). The presence of epitopes on the two faces of the cell membrane, as probed by antibody adsorption and crossed immunoelectrophoresis, and the strong interaction between spiralin and the intracytoplasmic fibrils show that spiralin is a transmembrane protein. The mean hydropathy of the amino acid composition of spiralin (-0.30) is on the hydrophilic side of the scale. Surprisingly, the water-insoluble core of spiralin micelles, which is the putative membrane anchor, has a still more hydrophilic amino acid composition (mean hydropathy, -0.70) and is enriched in glycine and serine residues. Taking into account all these properties, we propose a topological model for spiralin featuring a transbilayer localization with hydrophilic domains protruding on the two faces of the membrane and connected by a small domain embedded within the apolar region of the lipid bilayer. In this model, the membrane anchoring of the protein is strengthened by a covalently bound acyl chain.
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Affiliation(s)
- H Wróblewski
- Laboratoire d'Immunochimie des Membranes Bactériennes, Université de Rennes, France
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14
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15
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Abstract
Membranes of six spiroplasma strains belonging to different Spiroplasma species and subgroups were isolated by a combination of osmotic lysis and sonication in the presence of EDTA to block endogenous phospholipase activity. Analysis of membrane lipids showed that in addition to free and esterified cholesterol the spiroplasmas incorporated exogenous phospholipids from the growth medium. Sphingomyelin was preferentially incorporated from phosphatidylcholine-sphingomyelin vesicles or from the serum used to supplement the growth medium. Palmitate was incorporated better than oleate into membrane lipids synthesized by the organisms during growth. The major phospholipid synthesized by the spiroplasmas was phosphatidylglycerol. The positional distribution of the fatty acids in phosphatidylglycerol of Spiroplasma floricola resembled that found in Mycoplasma species, in which the saturated fatty acids prefer position 2 in the glycerol backbone and not position 1 as found in Acholeplasma species and elsewhere in nature. Electron paramagnetic resonance analysis of spin-labeled fatty acids incorporated into S. floricola membranes exhibited homogeneous single-component spectra without immobilized regions. The S. floricola membranes were more rigid than those of Acholeplasma laidlawii and less rigid than those of Mycoplasma gallisepticum.
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16
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Dickinson MJ, Townsend R, Curson SJ. Characterisation of a virus infecting the wall-free prokaryote Spiroplasma citri. Virology 1984; 135:524-35. [DOI: 10.1016/0042-6822(84)90206-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/1983] [Accepted: 03/02/1984] [Indexed: 11/27/2022]
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17
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Shirvan MH, Gross Z, Ne'eman Z, Rottem S. Isolation ofMycoplasma gallisepticum membranes by a mild alkaline-induced lysis of nonenergized cells. Curr Microbiol 1982. [DOI: 10.1007/bf01572606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Shirvan MH, Rottem S, Ne'eman Z, Bittman R. Isolation of mycoplasma membranes by dicyclohexylcarbodiimide-induced lysis. J Bacteriol 1982; 149:1124-8. [PMID: 7061381 PMCID: PMC216504 DOI: 10.1128/jb.149.3.1124-1128.1982] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
A simple procedure was devised to prepared membranes from Mycoplasma gallisepticum cells. The cells were lysed in an isosmotic NaCl solution by dicyclohexylcarbodiimide, which blocks ATPase activity and interferes with the regulation of cell volume. The procedure can be used to isolate membranes of other osmotically resistant mycoplasmas.
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20
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Wróblewski H, Burlot R, Thomas D. Adsorption of proteins from the Spiroplasma citri cell membrane by magnesium lauroyl-sarcosinate crystals. Biochimie 1981; 63:177-86. [PMID: 6164403 DOI: 10.1016/s0300-9084(81)80191-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Interactions between the ionic detergent Sarkosyl (sodium lauroyl sarcosinate), Mg2+ ions, and the Spiroplasma citri cell membrane were analyzed microscopically and electrophoretically. Studies were performed under conditions where membrane proteins were apparently not released from the membrane by the detergent (molar ratio of MgCl2/Sarkosyl = 0.5). Although the S. citri membrane interfered with the crystallization phenomenon to some extent, the formation of Sarkosyl-Mg2+ crystals occurred regardless to the sequence of addition of the three components. Concomitantly the structure of the membrane disintegrated and membrane components were adsorbed to the crystal surfaces. The membrane protein fraction bound to the crystals was composed of the majority of the putatively intrinsic polypeptides, including the amphiphilic protein spiralin, and several extrinsic polypeptides. The polypeptide compositions of M-bands (crystal fractions loaded with membrane material) prepared from S. citri cells and from isolated S. citri membranes were similar, as shown by sodium dodecyl-sulfate electrophoresis and crossed immunoelectrophoresis. These results show that, the S. citri cell membrane, in contrast to bacterial membranes, is not protected from the effect of Sarkosyl by Mg2+ ions.
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Wróblewski H. Electrophoretic analysis of the arrangement of spiralin and other major proteins in isolated Spiroplasma citri cell membranes. J Bacteriol 1981; 145:61-7. [PMID: 7462152 PMCID: PMC217244 DOI: 10.1128/jb.145.1.61-67.1981] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The arrangement of the amphiphilic protein spiralin and of the other major polypeptides in the Spiroplasma citri cell membrane was investigated by one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The analyses were performed on untreated membranes for the detection of disulfide bonds and on membranes treated with dimethylsuberimidate and dithiobis(succinimidyl propionate). All membranes were depleted of the bulk of extrinsic proteins. Spiralin monomers and oligomers (mainly dimers) were detected. Almost all the oligomers appeared to be stabilized by intermolecular disulfide bonds. Components D7 (39,000 daltons), D9 (51,000 daltons), D13 (69,000 daltons), D14b (76,000 daltons), D16 (89,000 daltons), and D17 (95,000 daltons), which are the other (presumably intrinsic) main polypeptides of the S. citri membrane, were also involved in homooligomers stabilized by disulfide bonds. However, in contrast to spiralin, larger amounts of D7, D9, and D14b were involved in high-molecular-weight multimers (molecular weight, greater than 400 X 10(3) after cross-linking with dithiobis(succinimidyl propionate). Extensive cross-linking with dimethylsuberimidate showed that spiralin was the polypeptide least readily integrated to large covalent complexes. These results suggest that spiralin probably does not form a two-dimensional network in the S. citri membrane depleted of the bulk of extrinsic proteins.
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Archer DB. The structure and functions of the mycoplasma membrane. INTERNATIONAL REVIEW OF CYTOLOGY 1981; 69:1-44. [PMID: 7012066 DOI: 10.1016/s0074-7696(08)62319-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Razin S, Kutner S, Efrati H, Rottem S. Phospholipid and cholesterol uptake by Mycoplasma cells and membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 598:628-40. [PMID: 7388026 DOI: 10.1016/0005-2736(80)90042-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The ability of growing mycoplasma cells and their isolated membranes to take up exogenous phospholipids was correlated with their ability to take up cholesterol. Horse serum or vesicles made of phosphatidylcholine and cholesterol served as lipid donors. Growing cells of five Mycoplasma species took up significant quantities of phosphatidylcholine and sphingomyelin as well as free and esterified cholesterol. In contrast, growing cells of three Acholeplasma species failed to take up any of the exogenous phospholipids, and only incorporated low amounts of free cholesterol and no esterified cholesterol. Hence, the ability of mycoplasmas to take up large quantities of cholesterol appears to be correlated with an ability to take up exogenous phospholipids. Isolated membranes of Mycoplasma capricolum and Acholeplasma laidlawii took up lower amounts of cholesterol than did membranes of growing cells and did not take up phospholipids. Inhibition of M. capricolum growth decreased the ability of the cells to take up exogenous phospholipids and cholesterol. The possibility that the contact between the lipid donors and the membrane involves specific receptors best exposed in actively growing cells is discussed.
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Townsend R, Burgess J, Plaskitt KA. Morphology and ultrastructure of helical and nonhelical strains of Spiroplasma citri. J Bacteriol 1980; 142:973-81. [PMID: 7380813 PMCID: PMC294124 DOI: 10.1128/jb.142.3.973-981.1980] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cells of the nonhelical strain of Spiroplasma citri underwent changes of morphology comparable to those which occurred in the normal helical strain. Cells of the nonhelical strain had the same ultrastructural features as helical cells and released long flexible fibrils similar to those seen in other spiroplasmas. Nonhelical organisms showed an increased tendency to aggregate, forming cell clusters of an unusual annular form. The cytoplasmic membrane of the nonhelical strain lacked a single protein present in all helical strains. Loss of helicity associated with the senescence of spiroplasma cells was not accompanied by the disappearance of this protein. Differences in colony morphology were shown to be a consequence of motility, and a technique was developed which facilitated the identification of nonmotile organisms.
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Townsend R, Archer DB, Plaskitt KA. Purification and preliminary characterization of Spiroplasma fibrils. J Bacteriol 1980; 142:694-700. [PMID: 7189752 PMCID: PMC294053 DOI: 10.1128/jb.142.2.694-700.1980] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Fibrils 3.5 nm in diameter were released from the honeybee spiroplasma (BC3) by treatment with detergents and then purified by isopycnic centrifugation. Purified fibrils were flexuous, of indeterminate length, and had an axial repeat of 8.5 nm. The fibrils were associated in pairs, but in 1 M salt formed aggregates with a marked striated appearance. Pronase completely degraded the fibrils, but trypsin had little effect. The fibrils were composed of a single protein of molecular weight 55,000 which represented about 1% of the total cell protein. A protein of molecular weight 26,000 appeared to be associated with the fibrils. The significance of this in relation to membrane attachment and the possible role of fibrils in maintenance of cell shape and in motility are discussed.
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Patel KR, Smith PF, Mayberry WR. Comparison of lipids from Spiroplasma citri and corn stunt spiroplasma. J Bacteriol 1978; 136:829-31. [PMID: 711681 PMCID: PMC218616 DOI: 10.1128/jb.136.2.829-831.1978] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The qualitative lipid composition of Spiroplasma citri and corn stunt spiroplasma is identical. Small amounts of acylated glucose and steryl glucoside were found.
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Wroblewski H, Burlot R, Johansson KE. Solubilization of Spiroplasma citri cell membrane proteins with the anionic detergent sodium lauroyl-sarcosinate (Sarkosyl). Biochimie 1978; 60:389-98. [PMID: 687677 DOI: 10.1016/s0300-9084(78)80672-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. Up to 90 per cent of the membrane proteins from Spiroplasma citri could be solubilized with the anionic detergent Sarkosyl (sodium lauroyl-sarcosinate). Maximal solubilization was obtained with 6 to 20 mumoles of of detergent per mg of membrane protein. The insoluble residue, comprising about 10 per cent of the membrane protein, contained mainly the protein spiralin, which is quantitatively the major one of this membrane. 2. Mg2+ ions completely prevented solubilization of the membrane proteins at a molar ratio of MgCl2/Sarkosyl greater than 0.5. 3. The selectivity of Sarkosyl was also tested at low detergent concentrations and in the presence of Mg2+ ions. Spiralin was the least soluble protein also under these conditions. Other proteins were not selectively solubilized. 4. An electrophoretical and immunoelectrophoretical approach was used to study the interaction between Sarkosyl and membrane proteins. The results indicated that Sarkosyl should be considered as a mild detergent which usually solubilizes membrane proteins without gross donformational changes. This hypothesis was supported by experiments with a membrane-bound enzyme in the presence of Sarkosyl.
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Patel KR, Mayberry-Carson KJ, Smith PF. Effect of external environmental factors on the morphology of Spiroplasma citri. J Bacteriol 1978; 133:925-31. [PMID: 24042 PMCID: PMC222105 DOI: 10.1128/jb.133.2.925-931.1978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spiroplasma citri was examined by electron microscopy for morphological changes when maintained under a variety of conditions. PPLO serum fraction maintained spiral and helical morphology of S. citri at pH values of 8.0, 7.5, and 7.0, but only partially at pH 6.0 and 5.0. The absence of PPLO serum fraction resulted in round, deteriorated cells at all pH values tested. Bovine serum albumin (BSA), Phytone, soluble starch, potato starch, spermine, lipid-extracted PPLO serum fraction, and lipid-extracted BSA could substitute for PPLO serum fraction in maintaining spiral and helical morphology at pH 7.5. At pH 5.0, only BSA, lipid-extracted BSA, and lipid-extracted PPLO serum fraction were effective. Only BSA supported growth of S. citri for more than two transfers, whereas all other substitutes could not support growth longer than two transfers.
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Braun EJ. A freeze-etch and thin-section study of mycoplasmas in Vinca rosea phloem. JOURNAL OF ULTRASTRUCTURE RESEARCH 1977; 60:44-51. [PMID: 875109 DOI: 10.1016/s0022-5320(77)80040-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Mudd JB, Ittig M, Roy B, Latrille J, Bové JM. Composition and enzyme activities of Spiroplasma citri membranes. J Bacteriol 1977; 129:1250-6. [PMID: 191432 PMCID: PMC235094 DOI: 10.1128/jb.129.3.1250-1256.1977] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spiroplasma citri was cultured in three different media that supplied cholesterol and fatty acids from: (i) horse serum, (ii) pleuropneumonia-like organism (PPLO) serum fraction, or (iii) bovine serum albumin-fatty acid-cholesterol. The ability of PPLO serum fraction to support growth varied by lot number. Neither PPLO serum fraction nor the bovine serum albumin medium supported growth as well as the horse serum medium. Analysis of cholesterol, lipid phosphorus, and membrane protein showed the horse serum- and PPLO-grown cells to be indistinguishable, but the bovine serum albumin-grown cells were deficient in lipid phosphorus. The three cultures did not show markedly different fatty acid compositions, but, in all cases, the cultures preferentially incorporated palmitic acid and discriminated against linoleic acid. Cultures grown for different times from logarithmic growth through a degenerative phase showed relatively constant ratios of cholesterol/protein and lipid phosphorus/protein. Fatty acid composition was also relatively constant at the different stages. Adenosine triphosphatase and p-nitrophenyl phosphatase were mainly associated with the membrane, whereas reduced nicotinamide adenine dinucleotide oxidase was either readily removed or not associated with the membrane. The reduced nicotinamide adenine dinucleotide oxidase was inactivated at temperatures above 35 degrees C.
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Freeman BA, Sissenstein R, McManus TT, Woodward JE, Lee IM, Mudd JB. Lipid composition and lipid metabolism of Spiroplasma citri. J Bacteriol 1976; 125:946-54. [PMID: 1254560 PMCID: PMC236170 DOI: 10.1128/jb.125.3.946-954.1976] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In a horse serum-based medium containing a full complement of fatty acids, cells of Spiroplasma citri were seen to preferentially incorporate palmitic acid. In the same medium, which had a steryl ester-to-sterol ratio of 3.64, a steryl ester-to-sterol ratio of 0.23 was seen in the cells, cholesterol being preferentially incorporated over cholesteryl ester. Like most other mycoplasmas, S. citri was shown to be unable to synthesize fatty acids or esterify cholesterol. The neutral lipids of S. citri grown in a medium containing horse serum consisted of free cholesterol, cholesteryl ester, free fatty acids, triglycerides and diglycerides. All polar lipids were phospholipids, with no glycolipids detected. These phospholipids, which are characteristic of many mycoplasmas, are phosphatidyl glycerol, diphosphatidyl glycerol, and their lyso derivatives. Sphingomyelin was also incorporated when cells were grown on horse serum. A sterol requirement for the growth of S. citri was confirmed using a serum-free medium supplemented with bovine serum albumin, palmitic acid, and various concentrations of sterols dissolved in Tween 80. The addition of palmitic acid stimulated growth but was not essential for growth. S citri was shown to grow best on cholesterol and beta-sitosterol and was able to grow on stigmasterol and ergosterol to a lesser degree. No growth was obtained using mevalonate, deoxycholate, or taurodeoxycholate as an alternative to sterol. S. citri was also able to grow when palmitic acid was replaced with oleic acid, linoleic acid, or linolenic acid. Alterations in the lipid composition of the growth medium and hence in the lipid composition of S. citri induced changes in the characteristic helical morphology of the cells, concurrent with loss of cell viability. Culture, age, and pH were also factors in determining cell morphology and viability.
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Wroblewski H. [Selective solubilization of Spiroplasma citri membrane proteins with sodium desoxycholate]. Biochimie 1975; 57:1095-8. [PMID: 1222145 DOI: 10.1016/s0300-9084(75)80367-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Whitcomb RF, Williamson DL. Helical wall-free prokaryotes in insects: multiplication and pathogenicity. Ann N Y Acad Sci 1975; 266:260-75. [PMID: 1072598 DOI: 10.1111/j.1749-6632.1975.tb35109.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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RAZIN SHMUEL. The Mycoplasma Membrane. ACTA ACUST UNITED AC 1975. [DOI: 10.1016/b978-0-12-571809-7.50010-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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Abstract
The helical wall-free microorganism, Spiroplasma citri, which is associated with citrus stubborn, a disease with no known vector, multiplied in the leafhopper vector of corn stunt but multiplied to higher titer in the vector of aster yellows and decreased the longevity of that insect. Acholeplasma laidlawii and A. granularum also multiplied in both leafhoppers.
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