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.

The fine structure and development of chlamydospores of Fusarium oxysporum

1972 ◽  
Vol 18 (7) ◽  
pp. 997-1002 ◽  
Author(s):  
I. L. Stevenson ◽  
S. A. W. E. Becker
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Fine Structure ◽  
Electron Microscope ◽  
Cell Surface ◽  
Outer Layer ◽  
Outer Wall ◽  
Wall Layer ◽  
Thin Sections ◽  
Hyphal Wall

Methods have been developed for the rapid, reproducible induction of high-density populations of F. oxysporum chlamydospores. On transferring washed pregerminated conidia to a simple two-salts medium, chlamydospore morphogenesis was evident by 12 h and masses of mature spores could be harvested at the end of 4 days. Electron-microscope studies of thin sections of mature chlamydospores reveal a thick triple-layered cell wall. The cytoplasm contains, in addition to large lipid deposits, a nucleus, mitochondria, and endoplasmic reticulum all typical of fungal cells. Chlamydospores of F. oxysporum exhibit two distinct types of cell surface in thin section. The outer wall layer of two of the isolates studied was smooth-surfaced while the outer layer of the two other isolates was distinctly fibrillose. Some evidence is presented suggesting that the fibrillose material arises through the partial breakdown of the original hyphal wall.

scholarly journals Cellulose synthase complexes display distinct dynamic behaviors during xylem transdifferentiation

2018 ◽  
Vol 115 (27) ◽  
pp. E6366-E6374 ◽  
Author(s):  
Yoichiro Watanabe ◽  
Rene Schneider ◽  
Sarah Barkwill ◽  
Eliana Gonzales-Vigil ◽  
Joseph L. Hill ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Expansion ◽  
Secondary Wall ◽  
Transition Period ◽  
Cellulose Synthase ◽  
Wall Thickening ◽  
Cellulose Synthesis ◽  
Primary Wall ◽  
Dynamic Behaviors

In plants, plasma membrane-embedded CELLULOSE SYNTHASE (CESA) enzyme complexes deposit cellulose polymers into the developing cell wall. Cellulose synthesis requires two different sets of CESA complexes that are active during cell expansion and secondary cell wall thickening, respectively. Hence, developing xylem cells, which first undergo cell expansion and subsequently deposit thick secondary walls, need to completely reorganize their CESA complexes from primary wall- to secondary wall-specific CESAs. Using live-cell imaging, we analyzed the principles underlying this remodeling. At the onset of secondary wall synthesis, the primary wall CESAs ceased to be delivered to the plasma membrane and were gradually removed from both the plasma membrane and the Golgi. For a brief transition period, both primary wall- and secondary wall-specific CESAs coexisted in banded domains of the plasma membrane where secondary wall synthesis is concentrated. During this transition, primary and secondary wall CESAs displayed discrete dynamic behaviors and sensitivities to the inhibitor isoxaben. As secondary wall-specific CESAs were delivered and inserted into the plasma membrane, the primary wall CESAs became concentrated in prevacuolar compartments and lytic vacuoles. This adjustment in localization between the two CESAs was accompanied by concurrent decreased primary wall CESA and increased secondary wall CESA protein abundance. Our data reveal distinct and dynamic subcellular trafficking patterns that underpin the remodeling of the cellulose biosynthetic machinery, resulting in the removal and degradation of the primary wall CESA complex with concurrent production and recycling of the secondary wall CESAs.

Cell wall development of Micrasterias americana, especially in isotonic and hypertonic solutions

1976 ◽  
Vol 21 (3) ◽  
pp. 617-631
Author(s):  
K. Ueda ◽  
S. Yoshioka
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Close Contact ◽  
Light And Electron Microscopy ◽  
Wall Layer ◽  
Wall Material ◽  
Cell Wall Development ◽  
Wall Growth ◽  
Wall Materials ◽  
Main Component

The cell wall development of Micrasterias americana was investigated by light and electron microscopy. From digestion experiments with pectinase and cellulase, and from fluorescence spectra in Calcofluor and Coriphosphin solution, it was concluded that pectin substances were the main component of the young developing cell wall and that cellulose was synthesized after the daughter hemicell was well developed. In 0-16 M mannitol, wall materials accumulated and were incompletely incorporated into the wall at the region where wall growth would be expected. The plasma membrane was in close contact with the cell wall at the sinus, and this contact was assumed to prevent penetration of wall material at this region, resulting in the accumulation of wall material at regions other than the sinus. The cellulosic wall layer was formed after the production of pectic substances in the 0-16 M mannitol. In 0-3 M mannitol neither a definite wall layer of cellulose nor a pectic wall was produced, presumably due to extensive dilution of the wall materials in the plasmolysed space between the cell wall and the plasma membrane. Under normal circumstances, the shape of the daughter cell is assumed to be determined by the shape of the developed primary wall, which is induced by precocious differentiation of the wall at the sinus.

scholarly journals Setting the boundaries: Primary cell wall synthesis and expansion

2011 ◽  
Vol 33 (2) ◽  
pp. 14-19
Author(s):  
Stephen C. Fry ◽  
Lenka Franková ◽  
Dimitra Chormova
Keyword(s):  
Cell Wall ◽  
Secondary Wall ◽  
Plant Cells ◽  
Wall Layer ◽  
Maximum Amount ◽  
Primary Cell Wall ◽  
Primary Wall ◽  
Cell Wall Synthesis ◽  
Outer Primary ◽  
Shape And Size

Mature plant cells typically have two-layered walls: a first-formed thin outer primary wall layer enclosing a later-formed thick inner secondary wall. The surface area of the primary wall limits the size of the cell and thus the maximum amount of biomass that can potentially be accumulated in the secondary wall. By controlling the shape and size of the cell, the primary wall therefore imposes the limits on the amount of inedible biofuel a plant cell can make.

scholarly journals THE STRUCTURE OF THE PRIMARY EPIDERMAL CELL WALL OF AVENA COLEOPTILES

1957 ◽  
Vol 3 (2) ◽  
pp. 171-182 ◽  
Author(s):  
S. T. Bayley ◽  
J. R. Colvin ◽  
F. P. Cooper ◽  
Cecily A. Martin-Smith
Keyword(s):  
Cell Wall ◽  
Outer Wall ◽  
Epidermal Cells ◽  
Cellulose Microfibrils ◽  
X Rays ◽  
Primary Wall ◽  
Normal Type ◽  
Number Of Layers ◽  
Angle Scattering ◽  
Epidermal Cell Wall

The primary walls of epidermal cells in Avena coleoptiles ranging in length from 2 to 40 mm. have been studied in the electron and polarizing microscopes and by the low-angle scattering of x-rays. The outer walls of these cells are composed of multiple layers of cellulose microfibrils oriented longitudinally; initially the number of layers is between 10 and 15 but this increases to about 25 in older tissue. Where epidermal cells touch, these multiple layers fuse gradually into a primary wall of the normal type between cells. In these radial walls, the microfibrils are oriented transversely. Possible mechanisms for the growth of the multilayered outer wall during cell elongation are discussed.

scholarly journals Cell wall biosynthesis and the molecular mechanism of plant enlargement

2009 ◽  
Vol 36 (5) ◽  
pp. 383 ◽  
Author(s):  
John S. Boyer
Keyword(s):  
Cell Wall ◽  
Critical Level ◽  
Turgor Pressure ◽  
Chara Corallina ◽  
Wall Material ◽  
Primary Wall ◽  
Terrestrial Plants ◽  
Green Plants ◽  
Wall Deposition ◽  
Wall Growth

Recently discovered reactions allow the green alga Chara corallina (Klien ex. Willd., em. R.D.W.) to grow well without the benefit of xyloglucan or rhamnogalactan II in its cell wall. Growth rates are controlled by polygalacturonic acid (pectate) bound with calcium in the primary wall, and the reactions remove calcium from these bonds when new pectate is supplied. The removal appears to occur preferentially in bonds distorted by wall tension produced by the turgor pressure (P). The loss of calcium accelerates irreversible wall extension if P is above a critical level. The new pectate (now calcium pectate) then binds to the wall and decelerates wall extension, depositing new wall material on and within the old wall. Together, these reactions create a non-enzymatic but stoichiometric link between wall growth and wall deposition. In green plants, pectate is one of the most conserved components of the primary wall, and it is therefore proposed that the acceleration-deceleration-wall deposition reactions are of wide occurrence likely to underlie growth in virtually all green plants. C. corallina is one of the closest relatives of the progenitors of terrestrial plants, and this review focuses on the pectate reactions and how they may fit existing theories of plant growth.

Spore wall development in Sphagnum lescurii

1982 ◽  
Vol 60 (11) ◽  
pp. 2394-2409 ◽  
Author(s):  
Roy Curtiss Brown ◽  
Betty E. Lemmon ◽  
Zane B. Carothers
Keyword(s):  
Plasma Membrane ◽  
Outer Layer ◽  
Mature Spore ◽  
Outer Wall ◽  
Spore Wall ◽  
Spore Surface ◽  
Proximal Surface ◽  
Complex Development ◽  
Surface Ornamentation ◽  
Cortical System

The spore wall of Sphagnum is unique in the Bryophyta. The Sphagnum spore exine consists of two layers: an inner, lamellate layer (A layer) and a thick, homogenous, outer layer (B layer). The exine of other mosses consists of only the outermost homogenous layer and, at most, a thin ill-defined opaque layer. During development of the A-layer exine and the intine, a cortical system of evenly spaced microtubules underlies the plasma membrane. The ontogeny of the wall layers is not strictly centripetal. The A-layer exine develops evenly around the young spore immediately after cytokinesis. As the intine is deposited centripetally inside it, the homogenous B-layer exine is deposited outside the first-formed A layer. The B layer is responsible for the primary sculpturing of the spore surface. The mature spore is covered by an outermost perine, which is responsible for secondary surface ornamentation. A trilaesurate aperture develops on the proximal surface of each spore after deposition of the A layer. Ridges of the laesurae develop as a result of deposition of thick areas of intine. The ridges are eventually covered by the outer wall layers, whereas the fissure is covered only by the A layer and a very thin B-layer exine. The complex development of the trilaesurate aperture is evidence that the structure is not merely a mechanically induced "trilete mark" or "scar" resulting from compression of tetrahedrally arranged spores within a sporocyte wall.

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.

scholarly journals The Nature of Reaction Wood III. Cell Division and Cell Wall Formation in Conifer Stems

1952 ◽  
Vol 5 (4) ◽  
pp. 385 ◽  
Author(s):  
ABW Ardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Secondary Wall ◽  
Compression Wood ◽  
Normal Wood ◽  
Reaction Wood ◽  
Primary Wall ◽  
Wall Formation ◽  
Tracheid Length ◽  
Secondary Wall Formation

Cell division, the nature of extra-cambial readjustment, and the development of the secondary wall in the tracheids of conifer stems have been investigated in both compression wood and normal wood. It has been shown that the reduction in tracheid length, accompanying the development of compression wood and, in normal wood, increased radial growth after suppression, result from an increase in the number of anticlinal divisions in the cambium. From observations of bifurcated and otherwise distorted cell tips in mature tracheids, of small but distinct terminal canals connecting the lumen to the primary wall in the tips of mature tracheids, and of the presence of only primary wall at the tips of partly differentiated tracheids, and from the failure to observe remnants of the parent primary walls at the ends of differentiating tracheids, it has been concluded that extra-cambial readjustment of developing cells proceeds by tip or intrusive growth. It has been further concluded that the development of the secondary wall is progressive towards the cell tips, on the bases of direct observation of secondary wall formation in developing tracheids and of the increase found in the number of turns of the micellar helix per cell with increasing cell length. The significance of this in relation to the submicroscopic organization of the cell wall has been discussed. Results of X-ray examinations and of measurements of� tracheid length in successive narrow tangential zones from the cambium into the xylem have indicated that secondary wall formation begins before the dimensional changes of differentiation are complete.

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.

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