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Gorobets S, Gorobets O, Sharai I, Polyakova T, Zablotskii V. Gradient Magnetic Field Accelerates Division of E. coli Nissle 1917. Cells 2023; 12:315. [PMID: 36672251 PMCID: PMC9857180 DOI: 10.3390/cells12020315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/07/2023] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
Cell-cycle progression is regulated by numerous intricate endogenous mechanisms, among which intracellular forces and protein motors are central players. Although it seems unlikely that it is possible to speed up this molecular machinery by applying tiny external forces to the cell, we show that magnetic forcing of magnetosensitive bacteria reduces the duration of the mitotic phase. In such bacteria, the coupling of the cell cycle to the splitting of chains of biogenic magnetic nanoparticles (BMNs) provides a biological realization of such forcing. Using a static gradient magnetic field of a special spatial configuration, in probiotic bacteria E. coli Nissle 1917, we shortened the duration of the mitotic phase and thereby accelerated cell division. Thus, focused magnetic gradient forces exerted on the BMN chains allowed us to intervene in the processes of division and growth of bacteria. The proposed magnetic-based cell division regulation strategy can improve the efficiency of microbial cell factories and medical applications of magnetosensitive bacteria.
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Affiliation(s)
- Svitlana Gorobets
- Faculty of Biotechnology and Biotechnics, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, 03056 Kyiv, Ukraine
| | - Oksana Gorobets
- Faculty of Physics and Mathematics, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, 03056 Kyiv, Ukraine
- Institute of Magnetism of the National Academy of Sciences of Ukraine and Ministry of Education and Science of Ukraine, 03142 Kyiv, Ukraine
| | - Iryna Sharai
- Faculty of Physics and Mathematics, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, 03056 Kyiv, Ukraine
- Institute of Magnetism of the National Academy of Sciences of Ukraine and Ministry of Education and Science of Ukraine, 03142 Kyiv, Ukraine
| | - Tatyana Polyakova
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague, Czech Republic
| | - Vitalii Zablotskii
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague, Czech Republic
- International Magnetobiology Frontier Research Center (iMFRC), Science Island, Hefei 230000, China
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2
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Norris V, Amar P. Chromosome Replication in Escherichia coli: Life on the Scales. Life (Basel) 2012; 2:286-312. [PMID: 25371267 PMCID: PMC4187155 DOI: 10.3390/life2040286] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 10/01/2012] [Accepted: 10/15/2012] [Indexed: 12/22/2022] Open
Abstract
At all levels of Life, systems evolve on the 'scales of equilibria'. At the level of bacteria, the individual cell must favor one of two opposing strategies and either take risks to grow or avoid risks to survive. It has been proposed in the Dualism hypothesis that the growth and survival strategies depend on non-equilibrium and equilibrium hyperstructures, respectively. It has been further proposed that the cell cycle itself is the way cells manage to balance the ratios of these types of hyperstructure so as to achieve the compromise solution of living on the two scales. Here, we attempt to re-interpret a major event, the initiation of chromosome replication in Escherichia coli, in the light of scales of equilibria. This entails thinking in terms of hyperstructures as responsible for intensity sensing and quantity sensing and how this sensing might help explain the role of the DnaA protein in initiation of replication. We outline experiments and an automaton approach to the cell cycle that should test and refine the scales concept.
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Affiliation(s)
- Vic Norris
- Theoretical Biology Unit, EA 3829, Department of Biology, University of Rouen, 76821, Mont Saint Aignan, France.
| | - Patrick Amar
- Laboratoire de Recherche en Informatique, Université Paris-Sud, and INRIA Saclay - Ile de France, AMIB Project, Orsay, France.
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3
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Mendelson NH, Shipman P, Roy D, Chen L, Thwaites JJ. The dynamic behavior of bacterial macrofibers growing with one end prevented from rotating: variation in shaft rotation along the fiber's length, and supercoil movement on a solid surface toward the constrained end. BMC Microbiol 2003; 3:18. [PMID: 12921542 PMCID: PMC194473 DOI: 10.1186/1471-2180-3-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2003] [Accepted: 08/16/2003] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Bacterial macrofibers twist as they grow, writhe, supercoil and wind up into plectonemic structures (helical forms the individual filaments of which cannot be taken apart without unwinding) that eventually carry loops at both of their ends. Terminal loops rotate about the axis of a fiber's shaft in contrary directions at increasing rate as the shaft elongates. Theory suggests that rotation rates should vary linearly along the length of a fiber ranging from maxima at the loop ends to zero at an intermediate point. Blocking rotation at one end of a fiber should lead to a single gradient: zero at the blocked end to maximum at the free end. We tested this conclusion by measuring directly the rotation at various distances along fiber length from the blocked end. The movement of supercoils over a solid surface was also measured in tethered macrofibers. RESULTS Macrofibers that hung down from a floating wire inserted through a terminal loop grew vertically and produced small plectonemic structures by supercoiling along their length. Using these as markers for shaft rotation we observed a uniform gradient of initial rotation rates with slopes of 25.6 degrees /min. mm. and 36.2 degrees /min. mm. in two different fibers. Measurements of the distal tip rotation in a third fiber as a function of length showed increases proportional to increases in length with constant of proportionality 79.2 rad/mm. Another fiber tethered to the floor grew horizontally with a length-doubling time of 74 min, made contact periodically with the floor and supercoiled repeatedly. The supercoils moved over the floor toward the tether at approximately 0.06 mm/min, 4 times faster than the fiber growth rate. Over a period of 800 minutes the fiber grew to 23 mm in length and was entirely retracted back to the tether by a process involving 29 supercoils. CONCLUSIONS The rate at which growing bacterial macrofibers rotated about the axis of the fiber shaft measured at various locations along fibers in structures prevented from rotating at one end reveal that the rate varied linearly from zero at the blocked end to maximum at the distal end. The increasing number of twisting cells in growing fibers caused the distal end to continuously rotate faster. When the free end was intermittently prevented from rotating a torque developed which was relieved by supercoiling. On a solid surface the supercoils moved toward the end permanently blocked from rotating as a result of supercoil rolling over the surface and the formation of new supercoils that reduced fiber length between the initial supercoil and the wire tether. All of the motions are ramifications of cell growth with twist and the highly ordered multicellular state of macrofibers.
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Affiliation(s)
- Neil H Mendelson
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA.
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4
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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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5
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Mendelson NH, Morales D, Thwaites JJ. The mechanisms responsible for 2-dimensional pattern formation in bacterial macrofiber populations grown on solid surfaces: fiber joining and the creation of exclusion zones. BMC Microbiol 2002; 2:1. [PMID: 11846887 PMCID: PMC65521 DOI: 10.1186/1471-2180-2-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2001] [Accepted: 01/28/2002] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND When Bacillus subtilis is cultured in a complex fluid medium under conditions where cell separation is suppressed, populations of multicellular macrofibers arise that mature into ball-like structures. The final sedentary forms are found distributed in patterns on the floor of the growth chamber although individual cells have no flagellar-driven motility. The nature of the patterns and their mode of formation are described in this communication. RESULTS Time-lapse video films reveal that fiber-fiber contact in high density populations of macrofibers resulted in their joining either by entwining or supercoiling. Joining led to the production of aggregate structures that eventually contained all of the fibers located in an initial area. Fibers were brought into contact by convection currents and motions associated with macrofiber self-assembly such as walking, pivoting and supercoiling. Large sedentary aggregate structures cleared surrounding areas of other structures by dragging them into the aggregate using supercoiling of extended fibers to power dragging. The spatial distribution of aggregate structures in 6 mature patterns containing a total of 637 structures was compared to that expected in random theoretical populations of the same size distributed in the same surface area. Observed and expected patterns differ significantly. The distances separating all nearest neighbors from one another in observed populations were also measured. The average distance obtained from 1451 measurements involving 519 structures was 0.73 cm. These spacings were achieved without the use of flagella or other conventional bacterial motility mechanisms. A simple mathematical model based upon joining of all structures within an area defined by the minimum observed distance between structures in populations explains the observed distributions very well. CONCLUSIONS Bacterial macrofibers are capable of colonizing a solid surface by forming large multicellular aggregate structures that are distributed in unique two-dimensional patterns. Cell growth geometry governs in an hierarchical way the formation of these patterns using forces associated with twisting and supercoiling to drive motions and the joining of structures together. Joining by entwining, supercoiling or dragging all require cell growth in a multicellular form, and all result in tightly fused aggregate structures.
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Affiliation(s)
- Neil H Mendelson
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| | - David Morales
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
- Department of Mathematics, University of Arizona, Tucson, AZ 85721
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6
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Davey HM, Kell DB. Flow cytometry and cell sorting of heterogeneous microbial populations: the importance of single-cell analyses. Microbiol Rev 1996; 60:641-96. [PMID: 8987359 PMCID: PMC239459 DOI: 10.1128/mr.60.4.641-696.1996] [Citation(s) in RCA: 263] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The most fundamental questions such as whether a cell is alive, in the sense of being able to divide or to form a colony, may sometimes be very hard to answer, since even axenic microbial cultures are extremely heterogeneous. Analyses that seek to correlate such things as viability, which is a property of an individual cell, with macroscopic measurements of culture variables such as ATP content, respiratory activity, and so on, must inevitably fail. It is therefore necessary to make physiological measurements on individual cells. Flow cytometry is such a technique, which allows one to analyze cells rapidly and individually and permits the quantitative analysis of microbial heterogeneity. It therefore offers many advantages over conventional measurements for both routine and more exploratory analyses of microbial properties. While the technique has been widely applied to the study of mammalian cells, is use in microbiology has until recently been much more limited, largely because of the smaller size of microbes and the consequently smaller optical signals obtainable from them. Since these technical barriers no longer hold, flow cytometry with appropriate stains has been used for the rapid discrimination and identification of microbial cells, for the rapid assessment of viability and of the heterogeneous distributions of a wealth of other more detailed physiological properties, for the analysis of antimicrobial drug-cell interactions, and for the isolation of high-yielding strains of biotechnological interest. Flow cytometric analyses provide an abundance of multivariate data, and special methods have been devised to exploit these. Ongoing advances mean that modern flow cytometers may now be used by nonspecialists to effect a renaissance in our understanding of microbial heterogeneity.
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Affiliation(s)
- H M Davey
- Institute of Biological Sciences, University of Wales, Aberystwyth, Dyfed, United Kingdom
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7
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Horne DS, Tomasz A. Possible role of a choline-containing teichoic acid in the maintenance of normal cell shape and physiology in Streptococcus oralis. J Bacteriol 1993; 175:1717-22. [PMID: 8449879 PMCID: PMC203966 DOI: 10.1128/jb.175.6.1717-1722.1993] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Streptococcus oralis ATCC 35037 took up radioactively labeled choline from growth medium. Most of the choline (80 to 90%) was incorporated into the cell wall teichoic acid, and about 10% was localized in the plasma membrane. While cells grew in choline-free medium, they did so at slow rates and produced cell walls with greatly reduced amounts of phosphate and no detectable choline. Cells grown in choline-free medium had grossly abnormal shape and size. Both biochemical and morphological abnormalities were reversible by addition of choline to the medium.
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Affiliation(s)
- D S Horne
- Department of Microbiology, Weber State University, Ogden, Utah 84408-2506
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8
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Gholamhoseinian A, Shen Z, Wu JJ, Piggot P. Regulation of transcription of the cell division gene ftsA during sporulation of Bacillus subtilis. J Bacteriol 1992; 174:4647-56. [PMID: 1624452 PMCID: PMC206260 DOI: 10.1128/jb.174.14.4647-4656.1992] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Three distinct 5' ends of ftsA mRNA were identified by S1 mapping and by primer extension analysis. These are thought to represent three transcription start sites. The transcripts from the downstream and upstream sites were detected throughout growth. The transcript from the middle site was not detected during exponential growth but was detected within 30 min of the start of sporulation, when it was the predominant transcript. Insertion of a cat cassette in the middle promoter, ftsAp2 (p2), did not affect vegetative growth but prevented postexponential symmetrical division and spore formation. Transcription from p2 was dependent on RNA polymerase containing sigma H, and promoter p2 resembled the consensus sigma H promoter. Transcription from p2 did not require expression of the spo0A, spo0B, spo0E, spo0F, or spo0K loci. Northern (RNA) blot analysis indicated that ftsA is cotranscribed with the adjacent ftsZ gene. Multiple promoters provide a mechanism by which essential vegetative genes can be subjected to sporulation control independent of control during vegetative growth. In the case of ftsA,Z, the promoters provide a mechanism to permit septum formation in conditions of nutrient depletion that might be expected to shut down the vegetative division machinery.
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Affiliation(s)
- A Gholamhoseinian
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
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9
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Kuroda A, Sekiguchi J. Molecular cloning and sequencing of a major Bacillus subtilis autolysin gene. J Bacteriol 1991; 173:7304-12. [PMID: 1682302 PMCID: PMC209238 DOI: 10.1128/jb.173.22.7304-7312.1991] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A major Bacillus subtilis 168S autolysin (N-acetylmuramoyl-L-alanine amidase [EC 3.5.1.28]) was purified and then cleaved with cyanogen bromide. The N-terminal amino acid sequence of one of the resultant peptides was determined in order to make synthetic oligonucleotides. A 2.5-kb EcoRI fragment was cloned into Escherichia coli JM109 and detected by colony hybridization by using the oligonucleotides as probes. Sequencing of the insert showed the presence of an open reading frame (designated cwlB), starting at a UUG codon, which encodes a polypeptide of 496 amino acids with a molecular mass of 52,623 Da. CWLB had a presumed signal peptide which is processed after Ala at position 24. Insertional inactivation of the cwlB gene of the B. subtilis chromosome led to an approximately 90% decrease in the total cell wall hydrolytic activity of stationary-phase cells and extraordinary resistance to cell lysis, even after 6 days of incubation at 37 degrees C. No apparent changes in cell morphology, motility, competence, sporulation, or germination were observed.
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Affiliation(s)
- A Kuroda
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
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10
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Janssen PH, Parker LE, Morgan HW. Filament formation in Thermus species in the presence of some D-amino acids or glycine. Antonie Van Leeuwenhoek 1991; 59:147-54. [PMID: 1867470 DOI: 10.1007/bf00580654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A number of strains of Thermus spp. changed morphology from rods of about 6 to 8 microns long to multicellular filaments (unsheathed trichomes) up to many hundreds of micrometres long with the addition of glycine or certain D-amino acids to the growth medium. Associated with this change was the formation of braided trichomes and occasionally true knots. Filament formation was reversible by the removal of the causal agent, but only if growth was possible. Electron microscopy suggested that the wall structure was not changed, but only that cells did not separate due to the continuous nature of the outer membrane layer. The filaments were thus multicellular. The constituent cells were similar in length to the normal rod-shaped cells. Filament formation by Thermus spp. may have applications in industrial scale culture of these extracellular enzyme-producing thermophilic bacteria.
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Affiliation(s)
- P H Janssen
- Thermophile and Microbial Biochemistry and Biotechnology Unit, University of Waikato, Hamilton, New Zealand
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11
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Tsuchido T, Svarachorn A, Soga H, Takano M. Lysis and aberrant morphology of Bacillus subtilis cells caused by surfactants and their relation to autolysin activity. Antimicrob Agents Chemother 1990; 34:781-5. [PMID: 2113794 PMCID: PMC171691 DOI: 10.1128/aac.34.5.781] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The surfactants tested in this study lysed Bacillus subtilis 168 cells at the logarithmic growth phase. Results obtained with inhibitors and a mutant that had defective autolytic enzymes suggested that cell lysis resulted from the deregulation of autolysin activity. The addition of surfactants at sublytic concentrations produced twisted cells, filamented cells, or both. Autolysins extracted with 5 M LiCl from the cell wall fraction and lysozyme added to cells that were treated with surfactants restored the apparently normal cell rod morphology, suggesting that surfactants interfere with the role of autolysins in normal construction of the cell envelope. The rates of cellular autolysis and autolysin activity remaining in growing cells after exposure to a surfactant at a sublytic concentration decreased, although the rate of turnover of cell wall peptidoglycan was the same as that of control cells. Surfactants were suggested to interact with the regulatory system of autolysins and, thus, to affect the activities of autolysins in B. subtilis cells and to cause either morphological changes or cell autolysis, depending on the concentration of surfactants.
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Affiliation(s)
- T Tsuchido
- Department of Fermentation Technology, Osaka University, Japan
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12
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Harry EJ, Wake RG. Cloning and expression of a Bacillus subtilis division initiation gene for which a homolog has not been identified in another organism. J Bacteriol 1989; 171:6835-9. [PMID: 2556376 PMCID: PMC210583 DOI: 10.1128/jb.171.12.6835-6839.1989] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The Bacillus subtilis 168 division initiation genes defined by the temperature-sensitive mutations ts-1 and ts-12 were cloned into a 10.5-kilobase EcoRI fragment of DNA in the lambda EMBL4 vector. The two genes were separated by approximately 3 kilobases. The gene in which the ts-1 mutation resides was shown to be the same as the B. subtilis homolog of the Escherichia coli ftsZ gene. The other gene was named divIB. It showed no homology to any previously identified gene and coded for a protein of 30.1 kilodaltons which was probably membrane bound.
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Affiliation(s)
- E J Harry
- Department of Biochemistry, University of Sydney, New South Wales, Australia
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13
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14
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Hernández-Muñiz W, Stevens SE. Significance of braided trichomes in the cyanobacterium Mastigocladus laminosus. J Bacteriol 1988; 170:1519-22. [PMID: 3127375 PMCID: PMC210996 DOI: 10.1128/jb.170.4.1519-1522.1988] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Loops and braids in filaments of the cyanobacterium Mastigocladus laminosus were observed. Braided filaments were generally in the form of a right-handed helix (87%) but were occasionally observed as left-handed helices (13%). It was demonstrated by time-lapse photomicrography that braids continued to grow as braids and that loops coiled into braids as growth proceeded. Measurements of the distance between grooves in 74 braids yielded an average distance of 13 +/- 3 micron, a result which suggests that braid formation is not random. We propose that the braids arise as a consequence of the helical growth of cells that make up the filaments of M. laminosus.
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Affiliation(s)
- W Hernández-Muñiz
- Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802
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15
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Abstract
A critique of both autogeneous and symbiotic hypotheses for the origin of microtubules and cilia and eukaryotic flagella (undulipodia) is presented. It is proposed that spirochetes provided the ancient eukaryotic cell with microtubules twice; cytoplasmic microtubules originated from phagocytosed spirochetes whereas axopodial tubules of undulipodia were transformed from ectosymbiotic spirochetes. A role in transport for microtubules in spirochetes together with a detailed scenario by which free-living spirochetes attached as ectosymbionts and subsequently differentiated into undulipodia is outlined. A mechanism for the continuity of motility in the form of "training" of the novel microtubular axoneme by the ancient spirochete motility apparatus is proposed. Transitional states (missing links) are unlikely to have survived. Constraints regarding the nature of the host cell are discussed. A corresponding flowchart of the early evolution of eukaryotes is presented in which plastids and mitochondria are polyphyletic in their origins.
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16
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Hernández-Muñiz W, Stevens SE. Characterization of the motile hormogonia of Mastigocladus laminosus. J Bacteriol 1987; 169:218-23. [PMID: 3098731 PMCID: PMC211756 DOI: 10.1128/jb.169.1.218-223.1987] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The cyanobacterium Mastigocladus laminosus produces motile hormogonia which move by gliding motility. These hormogonia were characterized in terms of their morphology, state of differentiation of the cells, optimal temperature for production and motility, minimal nutritional requirements to sustain motility, liberation of the hormogonium from its parental trichome, average surface velocity, and maximal concentration of agar through which the hormogonium may move. We found that an average hormogonium consisted of 13.6 cells of only the narrow-cell-type morphology. Gliding motility and the production of hormogonia were maximal at 45 degrees C. Agarose plus 0.20 mM Ca2+ was sufficient to sustain gliding motility. Hormogonia were liberated from the parental trichome by formation and lysis of a necridium. The average surface velocity of a hormogonium was 1.7 micron/s with a maximal velocity of 3 micron/s. Hormogonia were motile through 7% agar. Motile hormogonia leave a record of their passage in the form of easily visible tracks on the surface of solid media. Three types of tracks were observed: straight, sinusoidal, and circular. Normal, forward-directed motion involves screwlike rotation that describes a right-handed helix. However, observations are presented which suggest that rotational motion is not a prerequisite for gliding motility in this cyanobacterium.
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17
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Tormo A, Ayala JA, de Pedro MA, Aldea M, Vicente M. Interaction of FtsA and PBP3 proteins in the Escherichia coli septum. J Bacteriol 1986; 166:985-92. [PMID: 3011758 PMCID: PMC215222 DOI: 10.1128/jb.166.3.985-992.1986] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mutations in the ftsA gene of Escherichia coli conferred a higher resistance to lysis induced by penicillin or by a combination of cefsulodin and furazlocillin. The ftsA2 allele codes for an FtsA protein which is inactive at 42 degrees C but is able to regain its activity once it is transferred back to 30 degrees C; ftsA2 filaments formed at 42 degrees C in the presence of penicillin divided once the penicillin was removed and the temperature was lowered to 30 degrees C. Potential septation sites in the filaments of wild-type cells treated in the same way remained inactive. The binding of a radioactively labeled derivative of ampicillin to penicillin-binding protein 3 (PBP3) was significantly decreased in strain D-3, containing the mutant allele ftsA3, when the binding assay was performed at the restrictive temperature. A molecular species able to cross-react with an anti-PBP3 serum was nevertheless found to be present in the envelope of D-3 cells. These observations suggested that the FtsA protein, a protein with a structural and regulatory role in septation, and PBP3, a protein enzymatically active in the synthesis of murein for septation, interact with each other.
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18
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Favre D, Thwaites JJ, Mendelson NH. Kinetic studies of temperature-induced helix hand inversion in Bacillus subtilis macrofibers. J Bacteriol 1985; 164:1136-40. [PMID: 3934136 PMCID: PMC219307 DOI: 10.1128/jb.164.3.1136-1140.1985] [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: 01/08/2023] Open
Abstract
The inversion of Bacillus subtilis macrofibers from right to left handedness induced by a temperature upshift was compared with inversion from left to right handedness induced by a temperature downshift. Following an upshift the new steady-state growth rate was achieved prior to inversion of helix orientation. There was no discernible perturbation of growth rate at the time of inversion. The time required after a temperature shift up or down for fiber rotation in the original sense to cease was dependent on the temperature to which the fibers were transferred and was always shortest when this temperature was highest. The results suggest a basic asymmetry in the two inversion processes. Cessation of rotation in the right-to-left inversion appeared to reflect contributions of the old and new wall materials that depended on their twist values, whereas the left-to-right inversion appeared to require that a specific amount of newly made wall material be inserted into the cell surface. The degree of twist of the newly inserted right-handed material appeared not to influence the timing of inversion.
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19
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Abstract
When
Pseudomonas putida
40 was grown on a variety of liquid media in which oxygen became a limiting factor during growth, the latter stages of growth involved the elongation of cells without septation, which can result in the complete filamentation of the culture (up to several hundred micrometers long). The filaments appeared to consist of a chain of protoplasts within a common sacculus. Later these filaments were capable of a rapid fragmentation by septation to give a population of ordinary rods with a corresponding increase in the number of viable particles but no appreciable change in total bacterial mass. Filamentation did not occur if slow growth rates were maintained by restriction of oxygen availability from the beginning of growth. In complex media filaments were not formed during growth on 1% peptone alone, but the addition of 0.1 M phosphate or 6.6 � 10
−4
M EDTA induced extensive filamentation that was reversed by the addition of 6.6 � 10
−4
M Mg
2+
. In minimal media a much higher Mg
2+
concentration than that required for active growth or present in the complex media was usually required for filamentation. A very narrow range of Mg
2+
concentration promoted filamentation, and this optimum differed markedly depending on the carbon source used. Other medium variations which influenced the level of filamentation are reported. We found that most strains of
P. putida
(including the neotype strain) and
P. fluorescens
gave filaments under the conditions developed with strain 40, whereas several strains of
P. aeruginosa
failed to give filaments on the same media.
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Affiliation(s)
- R H Jensen
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California 92717
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20
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Gotoh N, Hanehara C, Tanino T. Isolation and characteristics of a short rod-shaped mutant ofPseudomonas aeruginosa. FEMS Microbiol Lett 1984. [DOI: 10.1111/j.1574-6968.1984.tb01332.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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21
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Chang LE, Pate JL, Betzig RJ. Isolation and characterization of nonspreading mutants of the gliding bacterium Cytophaga johnsonae. J Bacteriol 1984; 159:26-35. [PMID: 6735983 PMCID: PMC215587 DOI: 10.1128/jb.159.1.26-35.1984] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Three approaches were taken to isolate a total of 153 nonspreading mutants derived from our laboratory strain of Cytophaga johnsonae, UW101, or from its auxotrophic derivative, UW10538. Characterization of 109 of these mutants led to their placement in five general categories: (i) motile, nonspreading (MNS) mutants whose cells are motile to various degrees but whose colonies fail to spread on agar gels under any conditions of incubation; (ii) conditional nonspreading (CNS) mutants with motile cells whose colonies require more moisture to spread on agar gels than do those of wild-type cells; (iii) filamentous conditional motility (FCM) mutants whose cells grow as nonmotile filaments or as motile cells with wild-type morphology, depending on conditions of incubation; (iv) short, tumbling, nonspreading (STN) mutants with short cells that tumble constantly; and (v) truly nonmotile (TNM) mutants whose cells never move and whose colonies never spread under any conditions tested. All TNM mutants exhibited a remarkable pleiotropy not seen in the other four classes of mutants: all were resistant to 39 phages to which wild-type cells are sensitive, and all were unable to digest chitin, which is digested by wild-type cells. The correlation between ability to move and phage sensitivity was strengthened further by showing that 150 additional TNM mutants derived from UW101 and 43 TNM mutants derived from 29 independent isolates of C. johnsonae were resistant to all phages to which their parents were sensitive. Furthermore, motile revertants of TNM mutants became phage sensitive, and temperature-sensitive mutants were motile and phage sensitive at 25 degrees C and nonmotile and phage resistant at 32 degrees C. Evidence supports the conclusion that any mutation rendering cells truly nonmotile invariably alters cell surface-associated properties such as phage sensitivity and chitin digestion merely as a consequence of changing a moving cell surface to a static surface.
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22
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Zaritsky A, Mendelson NH. Helical macrofiber formation in Bacillus subtilis: inhibition by penicillin G. J Bacteriol 1984; 158:1182-7. [PMID: 6427191 PMCID: PMC215572 DOI: 10.1128/jb.158.3.1182-1187.1984] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The folding process required for helical macrofiber formation after the outgrowth of Bacillus subtilis spores was found to be blocked by very low concentrations of penicillin G (1 to 3 ng/ml). Under such conditions, growth and septation without cell separation resulted in characteristic disorganized multicellular structures. Higher concentrations (4 and 10 ng/ml) were needed to inhibit spore outgrowth and vegetative growth, respectively.
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23
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Mobley HL, Koch AL, Doyle RJ, Streips UN. Insertion and fate of the cell wall in Bacillus subtilis. J Bacteriol 1984; 158:169-79. [PMID: 6232259 PMCID: PMC215395 DOI: 10.1128/jb.158.1.169-179.1984] [Citation(s) in RCA: 74] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cell wall assembly was studied in autolysin-deficient and -sufficient strains of Bacillus subtilis. Two independent probes, one for peptidoglycan and the other for surface-accessible teichoic acid, were employed to monitor cell surface changes during growth. Cell walls were specifically labeled with N-acetyl-D-[3H]glucosamine, and after growth, autoradiographs were prepared for both cell types. The locations of silver grains revealed that label was progressively lost from numerous sites on the cell cylinders, whereas label was retained on the cell poles, even after several generations. In the autolysin-deficient and chain-forming strain, it was found that the distance between densely labeled poles approximately doubled after each generation of growth. In the autolysin-sufficient strain, it was found that the numbers of labeled cell poles remained nearly constant for several generations, supporting the premise that completed septa and poles are largely conserved during growth. Fluorescein-conjugated concanavalin A was also used to determine the distribution of alpha-D-glucosylated teichoic acid on the surfaces of growing cells. Strains with temperature-sensitive phosphoglucomutase were used because in these mutants, glycosylation of cell wall teichoic acids can be controlled by temperature shifts. When the bacteria were grown at 45 degrees C, which stops the glucosylation of teichoic acid, the cells gradually lost their ability to bind concanavalin A on their cylindrical surfaces, but they retained concanavalin A-reactive sites on their poles. Discrete areas on the cylinder, defined by the binding of fluorescent concanavalin A, were absent when the synthesis of glucosylated teichoic acid was inhibited during growth for several generations at the nonpermissive temperature. When the mutant was shifted from a nonpermissive to a permissive temperature, all areas of the cylinder became able to bind the labeled concanavalin A after about one-half generation. Old cell poles were able to bind the lectin after nearly one generation at the permissive temperature, showing that new wall synthesis does occur in the cell poles, although it occurs slowly. These data, based on both qualitative and quantitative experiments, support a model for cell wall assembly in B. subtilis, in which cylinders elongate by inside-to-outside growth, with degradation of the stress-bearing old wall in wild-type organisms. Loss of wall material, by turnover, from many sites on the cylinder may be necessary for intercalation of new wall and normal length extension. Poles tend to retain their wall components during division and are turned over much more slowly.
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24
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Saxe CL, Mendelson NH. Morphological and genetic characterization of a bacteriophage-resistant Bacillus subtilis macrofiber-producing strain. J Bacteriol 1984; 157:109-14. [PMID: 6418716 PMCID: PMC215137 DOI: 10.1128/jb.157.1.109-114.1984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bacillus subtilis C6 phi R4 is an SPO1-resistant derivative of strain C6D, a left-hand macrofiber-producing strain described previously (N. H. Mendelson, Proc. Natl. Acad. Sci. U.S.A. 75:2478-2482, 1978). In addition to the phage resistance property, strain C6 phi R4 differs from its parent in macrofiber organization and formation of aggregates in liquid shake cultures. The phage resistance mutation was located in the gtaC gene. The macrofiber organization and aggregation phenotypes also appear to be controlled by the gtaC locus. Strains constructed by introduction of the gtaC mutation into C6D appear to be identical to the original C6 phi R4 strain in all phenotypic properties. In contrast, other constructs carrying either gtaA or gtaB that are resistant to SPO1 do not display the characteristic C6 phi R4 morphological phenotypes.
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25
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Benjamin P, Firshein W. Initiation of DNA replication in vitro by a DNA-membrane complex extracted from Bacillus subtilis. Proc Natl Acad Sci U S A 1983; 80:6214-8. [PMID: 6137820 PMCID: PMC394266 DOI: 10.1073/pnas.80.20.6214] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Initiation of DNA replication has been observed in vitro with a DNA-membrane complex extracted from Bacillus subtilis. Antibiotics known to interfere with various aspects of initiation inhibited DNA synthesis significantly in vitro, whereas a mutant resistant to one inhibitor failed to respond to its presence. The inhibitory effects occurred primarily when the immediate RNA precursors (ribonucleoside triphosphates) were present in the assay solution but not significantly when the precursors were omitted. Complexes extracted from a temperature-sensitive initiation mutant were almost incapable of synthesizing DNA at the restrictive temperature but displayed extensive synthesis at the permissive temperature. A strong indication of semiconservative DNA synthesis was obtained in vitro after density-shift experiments involving incubation of the complex with a heavy-density DNA precursor, followed by neutral and alkaline CsCl density gradient centrifugation. A significant amount of chain elongation or repair (or both) was also observed.
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