scholarly journals Cell wall structure and deposition in Glaucocystis

1978 ◽  
Vol 77 (1) ◽  
pp. 103-119 ◽  
Author(s):  
JH Willison ◽  
RM Brown
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Plasma Membranes ◽  
Wall Structure ◽  
Unicellular Alga ◽  
Wall Deposition ◽  
Cellulose Deposition ◽  
Terminal Complexes ◽  
Mother Cells ◽  
In Transit

Events leading to cell wall formation in the ellipsoidal unicellular alga Glaucocystis are described. The wall is deposited in three phases: (a) a thin nonfibrillar layer, (b) cellulosic microfibrils arranged in helically crossed polylamellate fashion, and (c) matrix substances. At poles of cells, microfibrils do not terminate but pass around three equilaterally arranged points, resulting in microfibril continuity between the twelve helically wound wall layers. These findings were demonstrated in walls of both mother cells and freeze-fractured growing cells, and models of the wall structure are presented. Cellular extension results in spreading apart, and in rupture, of microfibrils. On freeze-fractured plasma membranes, there were 35 nm X 550 nm structures associated with the ends of microfibrils. These are interpreted as representing microfibril-synthesizing centers (terminal complexes) in transit upon the membrane. These terminal complexes are localized in a zone, or zones. The plasma membrane is subtended by flattened sacs, termed shields, which become cross-linked to the plasma membrane after completion of wall deposition. During wall deposition, microtubules lie beneath the shields, and polarized filaments lie between shields and plasma membrane. The significance of these findings in relation to understanding the process of cellulose deposition is discussed, and comparisons are made with the alga Oocystis.

The isolation of plasma membrane from protoplasts of soybean suspension cultures

1977 ◽  
Vol 24 (1) ◽  
pp. 295-310
Author(s):  
D.W. Galbraith ◽  
D.H. Northcote
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Membrane Fraction ◽  
Sucrose Gradient ◽  
Plasma Membranes ◽  
Gradient Centrifugation ◽  
Buoyant Density ◽  
Membrane Systems ◽  
Enzymic Digestion ◽  
Nadh Cytochrome

A procedure for the isolation of plasma membranes from protoplasts of suspension-cultured soybean is described. Protoplasts were prepared by enzymic digestion of the cell wall and the plasma membrane was labelled with radioactive diazotized sulphanilic acid. The membrane systems from broken protoplasts were separated by continuous isopycnic sucrose gradient centrifugation. Radioactivity was localized in a band possessing a buoyant density of 1–14 g ml-1. The activities of NADPH- and NADH-cytochrome c reductase, fumarase, Mg2+-ATPase, IDPase and acid phosphodiesterase in the various regions of the density gradient were determined. A plasma membrane fraction was selected which was relatively uncontaminated with membranes derived from endoplasmic reticulum, tonoplasts and mitochondria. The results indicated that Mg2+-ATPase and possibly acid phosphodiesterase were associated with the plasma membrane.

scholarly journals Wood Cell-Wall Structure Requires Local 2D-Microtubule Disassembly by a Novel Plasma Membrane-Anchored Protein

2010 ◽  
Vol 20 (13) ◽  
pp. 1197-1202 ◽  
Author(s):  
Yoshihisa Oda ◽  
Yuki Iida ◽  
Yuki Kondo ◽  
Hiroo Fukuda
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Wood Cell Wall ◽  
Cell Wall Structure ◽  
Wall Structure

scholarly journals Up against the Wall: Is Yeast Cell Wall Integrity Ensured by Mechanosensing in Plasma Membrane Microdomains?

2014 ◽  
Vol 81 (3) ◽  
pp. 806-811 ◽  
Author(s):  
Christian Kock ◽  
Yves F. Dufrêne ◽  
Jürgen J. Heinisch
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Yeast Cell ◽  
Antifungal Drugs ◽  
Cell Wall Integrity ◽  
Yeast Cell Wall ◽  
Membrane Microdomains ◽  
Wall Structure ◽  
Fungal Cell ◽  
Membrane Spanning

ABSTRACTYeast cell wall integrity (CWI) signaling serves as a model of the regulation of fungal cell wall synthesis and provides the basis for the development of antifungal drugs. A set of five membrane-spanning sensors (Wsc1 to Wsc3, Mid2, and Mtl1) detect cell surface stress and commence the signaling pathway upon perturbations of either the cell wall structure or the plasma membrane. We here summarize the latest advances in the structure/function relationship primarily of the Wsc1 sensor and critically review the evidence that it acts as a mechanosensor. The relevance and physiological significance of the information obtained for the function of the other CWI sensors, as well as expected future developments, are discussed.

Subcellular location of phage infection protein (Pip) inLactococcus lactis

2006 ◽  
Vol 52 (7) ◽  
pp. 664-672 ◽  
Author(s):  
Duane T Mooney ◽  
Monica Jann ◽  
Bruce L Geller
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Lactococcus Lactis ◽  
Plasma Membranes ◽  
Gradient Centrifugation ◽  
Subcellular Location ◽  
Recognition Site ◽  
Phage Infection ◽  
Sucrose Density Gradient Centrifugation ◽  
Membrane Spanning

The amino acid sequence of the phage infection protein (Pip) of Lactococcus lactis predicts a multiple-membrane-spanning region, suggesting that Pip may be anchored to the plasma membrane. However, a near-consensus sortase recognition site and a cell wall anchoring motif may also be present near the carboxy terminus. If functional, this recognition site could lead to covalent linkage of Pip to the cell wall. Pip was detected in both plasma membranes and envelopes (plasma membrane plus peptidoglycan) isolated from the wild-type Pip strain LM2301. Pip was firmly attached to membrane and envelope preparations and was solubilized only by treatment with detergent. Three mutant Pip proteins were separately made in which the multiple-membrane-spanning region was deleted (Pip-Δmmsr), the sortase recognition site was converted to the consensus (Pip-H841G), or the sortase recognition site was deleted (Pip-Δ6). All three mutant Pip proteins co-purified with membranes and could not be solubilized except with detergent. When membranes containing Pip-Δmmsr were sonicated and re-isolated by sucrose density gradient centrifugation, Pip-Δmmsr remained associated with the membranes. Strains that expressed Pip-H841G or Pip-Δ6 formed plaques with near unit efficiency, whereas the strain that expressed Pip-Δmmsr did not form plaques of phage c2. Both membranes and cell-free culture supernatant from the strain expressing Pip-Δmmsr inactivated phage c2. These results suggest that Pip is an integral membrane protein that is not anchored to the cell wall and that the multiple-membrane-spanning region is required for productive phage infection but not phage inactivation.Key words: phage infection protein, Pip, Lactococcus lactis, subcellular location.

scholarly journals A Novel Plasma Membrane-Anchored Protein Regulates Xylem Cell-Wall Deposition through Microtubule-Dependent Lateral Inhibition of Rho GTPase Domains

2017 ◽  
Vol 27 (16) ◽  
pp. 2522-2528.e4 ◽  
Author(s):  
Yuki Sugiyama ◽  
Mayumi Wakazaki ◽  
Kiminori Toyooka ◽  
Hiroo Fukuda ◽  
Yoshihisa Oda
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Lateral Inhibition ◽  
Rho Gtpase ◽  
Xylem Cell ◽  
Wall Deposition ◽  
Cell Wall Deposition

scholarly journals Prm1p, a Pheromone-Regulated Multispanning Membrane Protein, Facilitates Plasma Membrane Fusion during Yeast Mating

2000 ◽  
Vol 151 (3) ◽  
pp. 719-730 ◽  
Author(s):  
Maxwell G. Heiman ◽  
Peter Walter
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Membrane Fusion ◽  
Cell Fusion ◽  
Plasma Membranes ◽  
Molecular Mechanisms ◽  
Transmembrane Protein ◽  
Large Fraction ◽  
Cell Contact ◽  
Yeast Mating

Cell fusion occurs throughout development, from fertilization to organogenesis. The molecular mechanisms driving plasma membrane fusion in these processes remain unknown. While yeast mating offers an excellent model system in which to study cell fusion, all genes previously shown to regulate the process act at or before cell wall breakdown; i.e., well before the two plasma membranes have come in contact. Using a new strategy in which genomic data is used to predict which genes may possess a given function, we identified PRM1, a gene that is selectively expressed during mating and that encodes a multispanning transmembrane protein. Prm1p localizes to sites of cell–cell contact where fusion occurs. In matings between Δprm1 mutants, a large fraction of cells initiate zygote formation and degrade the cell wall separating mating partners but then fail to fuse. Electron microscopic analysis reveals that the two plasma membranes in these mating pairs are tightly apposed, remaining separated only by a uniform gap of ∼8 nm. Thus, the phenotype of Δprm1 mutants defines a new step in the mating reaction in which membranes are juxtaposed, possibly through a defined adherence junction, yet remain unfused. This phenotype suggests a role for Prm1p in plasma membrane fusion.

Two action sites of AM-toxin I produced by apple pathotype of Alternaria alternata in host cells: an ultrastructural study

1981 ◽  
Vol 59 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Pyoyun Park ◽  
Syoyo Nishimura ◽  
Keisuke Kohmoto ◽  
Hiroshi Otani ◽  
Kazuyuki Tsujimoto
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Amorphous Materials ◽  
Plasma Membranes ◽  
Host Cells ◽  
Ultrastructural Changes ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Moderately Resistant ◽  
Membrane Cell

The localization of primary action sites of AM-toxin I in host cells was examined by ultrastructural investigation and electron microscopic autoradiography. In susceptible apple leaves, the first effect of the toxin appeared 1 h after treatment in the plasma membranes and chloroplasts of mesophyll and vascular bundle sheath cells and in the plasma membranes of phloem and epidermal cells. Membranes and vesicles which were stained positively with a specific staining solution for grana lamellae were found in the matrix of the chloroplasts, showing that the membranous materials were derived from the disrupted grana. Cell wall lesions were formed around plasmodesmata where plasma membranes were invaginated. The invaginated sites were filled with amorphous materials from degraded cell walls, including membranes derived from plasma membranes and the desmotubules extending from plasmodesmata. The modified chloroplasts and plasma membranes were observed more often as the time after the toxin treatment was prolonged. Modified plastids were not found in the leaf cells. The other cellular membranes appeared normal even 10 h after the treatment. Resistant leaf cells were rarely affected by the toxin. Not all tissues from susceptible apples were sensitive as the toxin caused no necrosis or ultrastructural changes in petal cells. Resistant petal cells were also insensitive to the toxin, but the toxin causes necrosis and ultrastructural changes in moderately resistant petal cells in which the primary effect of the toxin appeared as plasma membrane modifications. Plastids were not affected by the toxin. These results indicate that the action sites of the toxin may be located on the plasma membrane – cell wall association in susceptible leaf cells and in moderately resistant petal cells and also on the chloroplasts of susceptible cells. The results of electron microscopic autoradiography also provided evidence that the action sites of the toxin were present on chloroplasts and the plasma membrane –cell wall association of susceptible leaf cells.

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