Ultrastructure of a marine psychrophilic Vibrio

1970 ◽  
Vol 16 (11) ◽  
pp. 1027-1031 ◽  
Author(s):  
S. F. Kennedy ◽  
R. R. Colwell ◽  
G. B. Chapman
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Division ◽  
Wall Material ◽  
Cross Wall ◽  
Growth Stages ◽  
Culture Age ◽  
Primary Mechanism ◽  
Age Studies

The structure of Vibrio marinus strain PS-207 was studied by both phase and electron microscopy. It was found to possess a trilaminar plasma membrane and cell wall. Membrane-bounded subunits containing DNA-like material were found dispersed throughout the cytoplasm. Giant round forms or "macrospheres" were observed in all growth stages. The size, shape, and construction of the "macrospheres" showed some variation, but could not be related to culture age. Studies of cell division in V. marinus strain PS-207 indicate the primary mechanism to be a synthesis and centripetal deposition of plasma membrane with a concomitant or subsequent synthesis and centripetal deposition of cross wall material.

CELL WALL REPLICATION: II. CELL WALL GROWTH AND CROSS WALL FORMATION OF ESCHERICHIA COLI AND STREPTOCOCCUS FAECALIS

1964 ◽  
Vol 10 (3) ◽  
pp. 473-482 ◽  
Author(s):  
K. L. Chung ◽  
R. Z. Hawirko ◽  
P. K. Isaac
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Initial Step ◽  
Wall Material ◽  
Cross Wall ◽  
Cell Wall Growth ◽  
E Coli ◽  
Rapid Enlargement ◽  
Wall Growth ◽  
Polar Type

Cell wall replication in E. coli and S. faecalis was studied by differential labelling of living cells with fluorescent and non-fluorescent antibody.In E. coli the initial step in cell division was the formation of a cross wall at the cell equator, followed by the appearance of new cell wall on either side of the cross wall. The process was repeated in sequence at subsequent sites in the polar, the subcentral, and the subpolar areas. Constriction occurred at random so that the divided parent cells were composed of several daughter cells.A polar type of unidirectional cell wall growth and elongation was also observed in E. coli. It was initiated by the synthesis of a ring of new cell wall material around the polar tip. A second ring was then formed at the subpolar area during the rapid enlargement of the first ring in a single direction.Evidence shows that cell wall synthesis is independent of cell division and that in E. coli, it is initiated at multiple but specific sites within the cell and not by diffuse intercalation of old and new walls.Contrary to the synthesis of cell wall at multiple sites in E. coli, S. faecalis replicated new cell wall at only one site per coccus. The new wall segment was initiated and enlarged at the coccal equator, and was followed by the formation of a cross wall, centripetal growth and constriction to separate the daughter cells.

scholarly journals Daptomycin Exerts Bactericidal Activity without Lysis of Staphylococcus aureus

2008 ◽  
Vol 52 (6) ◽  
pp. 2223-2225 ◽  
Author(s):  
Nicole Cotroneo ◽  
Robert Harris ◽  
Nancy Perlmutter ◽  
Terry Beveridge ◽  
Jared A. Silverman
Keyword(s):  
Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Division ◽  
Bactericidal Activity ◽  
Membrane Integrity ◽  
Cell Lysis

ABSTRACT The ability of daptomycin to produce bactericidal activity against Staphylococcus aureus while causing negligible cell lysis has been demonstrated using electron microscopy and the membrane integrity probes calcein and ToPro3. The formation of aberrant septa on the cell wall, suggestive of impairment of the cell division machinery, was also observed.

Ultrastructural changes of the plasmalemma and the cell wall during the life cycle of Cyanidium caldarium

1968 ◽  
Vol 171 (1023) ◽  
pp. 249-259 ◽  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Life Cycle ◽  
Cell Division ◽  
Surface Pattern ◽  
Ultrastructural Changes ◽  
Adjacent Cell ◽  
Cyanidium Caldarium ◽  
Stage Of Development ◽  
Dominant Feature

During the life cycle of the unicellular alga Cyanidium caldarium the surfaces of the plasmalemma and the adjacent cell wall develop a number of differentiated structures which can be demonstrated with the freeze-etching technique. While cell division takes place, the plasma membrane is undifferentiated and covered with randomly distributed 55 and 80 Å particles as well as small holes from torn out particles that can be found adhering to the adjacent cell wall. The 80 Å particles possess a substructure and sometimes 40 Å fibrils can be seen leading from these particles into the cell wall. Just after cell division, shallow depressions showing a hexagonal surface pattern with a spacing of 105 Å and arrays of approximately hexagonally packed 55 Å particles are formed on the plasmalemma. The corresponding structures found on the cell wall are particle-studded humps, which fit into the shallow depressions, and faintly striated regions, which match the 55 Å particle arrays. During the next stage of development, the hexagonally patterned shallow depressions on the plasma membrane are transformed into regularly striated 300 to 350 Å wide and approximately 250 Å deep folds, while the arrays of 55 Å particles increase in size. On the adjacent cell wall we can follow the development of the particle-studded humps into ridges covered with 70 Å particles. The plasmalemma of old mature cells is characterized by long striated folds that replace nearly all network structured depressions, and a few small arrays of 55 Å particles. Long ridges covered with particles are the corresponding dominant feature on the inside of the cell wall. Prior to cell division, the striated folds and the other differentiations of the plasmalemma are broken down and eventually disappear so that the cell has again an undifferentiated ‘embryonic’ plasma membrane for cell division. Simultaneously the differentiated structures on the cell wall disappear. All the described particles and units forming plasma membrane differentiations seem to be confined to the surface layer of the plasmalemma. The outlined development cycle of the plasmalemma of Cyanidium shows that biological membranes have the potential to differentiate in time and space.

scholarly journals Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion

2021 ◽  
Author(s):  
Olivia Muriel ◽  
Laetitia Michon ◽  
Wanda Kukulski ◽  
Sophie G Martin
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Sexual Reproduction ◽  
Membrane Fusion ◽  
Cell Fusion ◽  
Turgor Pressure ◽  
Wall Material ◽  
M Cells ◽  
P Cells ◽  
Cell Cell

Cell-cell fusion is central to the process of fertilization for sexual reproduction. This necessitates the remodeling of peri-cellular matrix or cell wall material and the merging of plasma membranes. In walled fission yeast S. pombe, the fusion of P and M cells during sexual reproduction relies on the fusion focus, an actin structure that concentrates glucanase-containing secretory vesicles for local cell wall digestion necessary for membrane fusion. Here, we present a correlative light and electron microscopy (CLEM) quantitative study of a large dataset of 3D tomograms of the fusion site, which revealed the ultrastructure of the fusion focus as an actin-containing, vesicle-dense structure excluding other organelles. Unexpectedly, the data revealed asymmetries between the two gametes: M-cells exhibit a taut and convex plasma membrane that progressively protrudes into P-cells, which exhibit a more slack, wavy plasma membrane. These asymmetries are relaxed upon plasma membrane fusion, with observations of ramified pores that may result from multiple initiations or inhomogeneous expansion. We show that P-cells have a higher exo- to endocytosis ratio than M-cells, and that local reduction in exocytosis abrogates membrane waviness and compromises cell fusion significantly more in P- than M-cells. Reciprocally, reduction of turgor pressure specifically in M-cells prevents their protrusions into P-cells and delays cell fusion. Thus, asymmetric membrane conformations, which result from differential turgor pressure and exocytosis/endocytosis ratios between mating types, favor cell-cell fusion.

Contractile elements of Lemna trisulca L. glycerinated cell models during chloroplast translocations

2000 ◽  
Vol 78 (4) ◽  
pp. 503-510
Author(s):  
Robert A Rinaldi ◽  
Barbara Kalisz-Nowak ◽  
Wlodzimierz Korohoda ◽  
Stanislaw Wieckowski ◽  
Wincenty Kilarski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Contractile Element ◽  
Cell Models ◽  
Chloroplast Membranes ◽  
Chloroplast Membrane ◽  
Membrane Cell

Electron microscopy of Lemna glycerinated cell models depicts contractile elements during chloroplast translocations. One contractile element, the thin ectoplasmic layer, is [Formula: see text] 0.4 µm thick, pressed against plasma membrane-cell wall. Thin ectoplasmic layer contains numerous oriented filaments and some appear to be actin and myosin. Another contractile element is the outer chloroplast membrane which envelops each chloroplast and joins or fuses with the thin ectoplasmic layer. Choroplast interconnections are formed between two or more chloroplasts by outer chloroplast membranes; they enhance chloroplast communications, translocations, and molecular exchanges.Key words: chloroplast translocations, contractility, tubular connections.

Enlarged Crystalline Patches on the Plasma Membrane of Yeast Protoplasts

1980 ◽  
Vol 38 ◽  
pp. 686-687
Author(s):  
G. Sosinsky ◽  
R. Schekman ◽  
R. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
High Resolution Electron Microscopy ◽  
Yeast Cells ◽  
Physiological Conditions ◽  
Resolution Electron ◽  
Yeast Protoplasts ◽  
Intramembraneous Particles ◽  
Crystalline Array

The crystalline patches of intramembraneous particles that form in the yeast plasma membrane, under stationary state physiological conditions, represent a potentially interesting specimen for high resolution electron microscopy. Isolation of these crystalline membrane patches first requires removal of the cell wall and the formation of osmotically fragile yeast protoplasts. In developing a procedure for the isolation of these crystalline membrane patches, we have found that the intramembraneous particles form much larger crystalline patches in protoplasts than in intact yeast cells. We have performed deep etch experiments and have found that the crystalline array of particles is not expressed on the extracellular surface of the plasma membrane.

Cell wall structures of Epicoccum nigrum (Hyphomycetes)

1973 ◽  
Vol 51 (5) ◽  
pp. 1071-1073 ◽  
Author(s):  
J. A. Brushaber ◽  
R. H. Haskins
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Outer Layer ◽  
Secondary Wall ◽  
Outer Wall ◽  
Wall Layer ◽  
Wall Material ◽  
Primary Wall ◽  
Electron Dense Material ◽  
Wall Structures

Two structurally distinct types of secondary wall layers are present in older hyphae in addition to the primary wall. A coarsely fibrous outer wall layer often becomes quite massive and frequently fuses with the outer wall layers of adjacent cells in the formation of hyphal strands. The uneven deposition of this outer layer often produces large verrucosities. The inner secondary wall layer is relatively electron transparent and contains a reticulum of electron-dense lines. The interface of the inner secondary wall with the cytoplasm is often very irregular, and sections of the plasma membrane are frequently overlain by wall material. The outer secondary wall of conidia is composed of an electron-dense material different from that of the outer wall of hyphae. Cells in the multicellular conidia tend to be polyhedral in shape with either very thick primary walls or thin primary walls having a thick inner wall deposit.

Cytological comparison of early stages of wall regeneration of Cercospora nicotianae and Neurospora crassa protoplasts

1989 ◽  
Vol 67 (7) ◽  
pp. 1938-1943 ◽  
Author(s):  
Kimberly D. Gwinn ◽  
Margaret E. Daub ◽  
Pi-Yu Huang
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Neurospora Crassa ◽  
Protoplast Isolation ◽  
Differential Sensitivity ◽  
Wall Material ◽  
Wall Structure ◽  
Cell Wall Material ◽  
Isolated Protoplasts ◽  
Regeneration Period

Freshly isolated protoplasts of Cercospora nicotianae and Neurospora crassa are equally sensitive to the toxin, cercosporin. After a 12-h regeneration period C. nicotianae cells are resistant, but N. crassa cells remain sensitive. Production of cell wall material by both C. nicotianae and N. crassa was monitored by transmission electron microscopy and fluorescence microscopy. Freshly isolated protoplasts lacked cell wall material as shown by observation with electron microscopy and inability to bind the fluorescent brightener Tinopal 5BM. After a 12-h incubation, electron micrographs of regenerating protoplasts showed well-developed cell walls for N. crassa, whereas C. nicotianae displayed variations in wall structure. Ability to bind Tinopal 5BM was acquired very early by regenerating cells of both fungi. Percentages of cells that could bind Concanavalin A did not differ between the two fungi at any time after protoplast isolation. Ability to bind wheat germ agglutinin and Bandeiraea simplicifolia agglutinin II was detected earlier in C. nicotianae than in N. crassa. These data demonstrate the presence of cell wall materials in both C. nicotianae and N. crassa at the time that differential sensitivity to cercosporin is observed. These results suggest that components in the C. nicotianae cell wall may play a role in cercosporin resistance.

scholarly journals Dynamics of structural polysaccharides deposition on the plasma-membrane surface of plant protoplasts during cell wall regeneration

2019 ◽  
Vol 65 (1) ◽  
Author(s):  
Satomi Tagawa ◽  
Yusuke Yamagishi ◽  
Ugai Watanabe ◽  
Ryo Funada ◽  
Tetsuo Kondo
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Stress Condition ◽  
Laser Scanning Microscopy ◽  
Primary Cell ◽  
Wall Material ◽  
Primary Cell Wall ◽  
Cell Wall Regeneration ◽  
Plant Protoplasts ◽  
Wall Regeneration

Abstract In this study, dynamic changes in structural polysaccharide deposition on the plasma membrane and cortical microtubules (CMTs) behavior were monitored in protoplasts isolated from white birch callus using confocal laser scanning microscopy and atomic force microscopy. We focused on the influence of an environmental stimulus on cell wall regeneration in protoplasts by employing an acidic culture medium containing a high concentration of Ca2+ (the stress condition). Under the non-stress condition, cellulose microfibrils and callose were initially synthesized, and thereafter deposited on the plasma membrane as “primary cell wall material”. Under the stress condition, callose micro-sized fibers were secreted without cell wall regeneration. Behavior of CMTs labeled with mammalian microtubule-associated protein 4 with green fluorescent protein in transgenic protoplasts was monitored by time-lapse video analysis. Under the non-stress condition, CMTs behavior showed a linear arrangement at a fixed position, whereas unfixed manner of CMTs behavior was observed under the stress condition. These findings indicate that excessive Ca2+ affects cellulose synthesis and CMTs dynamics in plant protoplasts. Current study first demonstrated dynamics of cell wall regeneration and CMTs in woody protoplast, which provides novel insight to aid in understanding early stages of primary cell wall formation in plants.

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