Recruitment of myosin VIII towards plastid surfaces is root-cap specific and provides the evidence for actomyosin involvement in root osmosensing

2005 ◽  
Vol 32 (8) ◽  
pp. 721 ◽  
Author(s):  
Przemysław Wojtaszek ◽  
Anna Anielska-Mazur ◽  
Halina Gabryś ◽  
František Baluška ◽  
Dieter Volkmann
Keyword(s):  
Cell Wall ◽  
Root Cap ◽  
Volume Control ◽  
Animal Cells ◽  
Active Involvement ◽  
A Cell ◽  
Osmotic Stimulus ◽  
Tight Association ◽  
The Individual ◽  
Cellular Compartments

The existence of a cell wall–plasma membrane–cytoskeleton (WMC) continuum in plants has long been postulated. However, the individual molecules building such a continuum are still largely unknown. We test here the hypothesis that the integrin-based multiprotein complexes of animal cells have been replaced in plants with more dynamic entities. Using an experimental approach based on protoplast digestion mixtures, and utilising specific antibodies against Arabidopsis ATM1 myosin, we reveal possible roles played by plant-specific unconventional myosin VIII in the functioning of WMC continuum. We demonstrate rapid relocation (less than 5 min) of myosin VIII to statolith surfaces in maize root-cap cells, which is accompanied by the reorganisation of actin cytoskeleton. Upon prolonged stimulation, myosin VIII is also recruited to plasmodesmata and pit-fields of plasmolysing root cap statocytes. The osmotic stimulus is the major factor inducing relocation, but the cell wall–cytoskeleton interactions also play an important role. In addition, we demonstrate the tight association of myosin VIII with the surfaces of chloroplasts, and provide an indication for the differences in the mechanisms of plastid movement in roots and leaves of plants. Overall, our data provide evidence for the active involvement of actomyosin complexes, rooted in the WMC continuum, in the cellular volume control and maintenance of spatial relationships between cellular compartments.

Cytological and histochemical characteristics of the axenic root surface of Alnus glutinosa

1986 ◽  
Vol 64 (10) ◽  
pp. 2216-2226 ◽  
Author(s):  
Yves Prin ◽  
Mireille Rougier
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Root Hairs ◽  
Root Apex ◽  
Alnus Glutinosa ◽  
Root Surface ◽  
Infection Process ◽  
Root Cap ◽  
A Cell ◽  
Histochemical Tests

The aim of the present study was to investigate the Alnus root surface using seedlings grown axenically. This study has focused on root zones where infection by the symbiotic actinomycete Frankia takes place. The zones examined extend from the root cap to the emerging root hair zone. The root cap ensheaths the Alnus root apex and extends over the root surface as a layer of highly flattened cells closely appressed to the root epidermal cell wall. These cells contain phenolic compounds as demonstrated by various histochemical tests. They are externally bordered by a thin cell wall coated by a thin mucilage layer. The root cap is ruptured when underlying epidermal cells elongate, and cell remnants are still found in the emerging root hair zone. Young emerging root hairs are bordered externally by a cell wall covered by a thin mucilage layer which reacts positively to the tests used for the detection of polysaccharides, glycoproteins, and anionic sites. The characteristics of the Alnus root surface and the biological function of mucilage and phenols present at the root surface are discussed in relation to the infection process.

The ultrastructure of Methanothrix concilii, a mesophilic aceticlastic methanogen

1986 ◽  
Vol 32 (9) ◽  
pp. 703-710 ◽  
Author(s):  
Terry J. Beveridge ◽  
Girish B. Patel ◽  
Bob J. Harris ◽  
G. Dennis Sprott
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Circular Plates ◽  
A Cell ◽  
Granular Matrix ◽  
A Chain ◽  
The Individual

Methanothrix concilii strain GP6 consists of a chain of rod-shaped cells, ca. 2.5 μm in length and 0.8 μm in width, which are encased in a tubular proteinaceous sheath. The sheath is composed of annular hoops, ca. 8.0 nm wide and 9.0 nm thick, which are stacked together to form the tube. The ends of the sheath, and therefore the cell filament, are blocked by single, multilayered, 13.5 nm thick, circular plates, designated as "spacer plugs," which contain a series of concentric rings; these also separate the individual cells within each filament. Each cell is therefore bounded by a tubular section of sheath and two spacer plugs. Completely encapsulating each cell, and lying between the sheath and cell, is an amorphous granular matrix. Overlying the plasma membrane and surrounding each protoplast is a thin veil of material which resembles a cell wall, but which is unable to maintain the rod shape when cells are extruded from the sheath.

The Cell's Biological Rods and Ropes

MRS Bulletin ◽  
1999 ◽  
Vol 24 (10) ◽  
pp. 27-31 ◽  
Author(s):  
David Boal
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Chemical Composition ◽  
Intermediate Filaments ◽  
Plant Cells ◽  
Cell Type ◽  
Animal Cells ◽  
Limited Variation ◽  
A Cell ◽  
Mechanical Elements

Despite a variety of shapes and sizes, the generic mechanical structure of cells is remarkably similar from one cell type to the next. All cells are bounded by a plasma membrane, a fluid sheet that controls the passage of materials into and out of the cell. Plant cells and bacteria reinforce this membrane with a cell wall, permitting the cell to operate at an elevated osmotic pressure. Simple cells, such as the bacterium shown in Figure 1a, possess a fairly homogeneous interior containing the cell's genetic blueprint and protein workhorses, but no mechanical elements. In contrast, as can be seen in Figure 1b, plant and animal cells contain internal compartments and a filamentous cytoskeleton—a network of biological ropes, cables, and poles that helps maintain the cell's shape and organize its contents.Four principal types of filaments are found in the cytoskeleton: spectrin, actin, microtubules, and a family of intermediate filaments. Not all filaments are present in all cells. The chemical composition of the filaments shows only limited variation from one cell to another, even in organisms as diverse as humans and yeasts. Membranes have a more variable composition, consisting of a bi-layer of dual-chain lipid molecules in which are embedded various proteins and frequently a moderate concentration of cholesterol. The similarity of the cell's mechanical elements in chemical composition and physical characteristics encourages us to search for universal strategies that have developed in nature for the engineering specifications of the cell. In this article, we concentrate on the cytoskeleton and its filaments.

scholarly journals A Single-Cell Platform for Monitoring Viral Proteolytic Cleavage in Different Cellular Compartments

2015 ◽  
Vol 8s2 ◽  
pp. BCI.S30379
Author(s):  
Darin Abbadessa ◽  
Cameron A. Smurthwaite ◽  
Connor W. Reed ◽  
Roland Wolkowicz
Keyword(s):  
Drug Discovery ◽  
Biomedical Research ◽  
Envelope Protein ◽  
Viral Infectivity ◽  
Host Proteins ◽  
Subcellular Compartment ◽  
A Cell ◽  
The Individual ◽  
Cellular Compartments ◽  
Hiv 1

Infectious diseases affect human health despite advances in biomedical research and drug discovery. Among these, viruses are especially difficult to tackle due to the sudden transfer from animals to humans, high mutational rates, resistance to current treatments, and the intricacies of their molecular interactions with the host. As an example of these interactions, we describe a cell-based approach to monitor specific proteolytic events executed by either the viral-encoded protease or by host proteins on the virus. We then emphasize the significance of examining proteolysis within the subcellular compartment where cleavage occurs naturally. We show the power of stable expression, highlighting the usefulness of the cell-based multiplexed approach, which we have adapted to two independent assays previously developed to monitor (a) the activity of the HIV-1-encoded protease or (b) the cleavage of the HIV-1-encoded envelope protein by the host. Multiplexing was achieved by mixing cells each carrying a different assay or, alternatively, by engineering cells expressing two assays. Multiplexing relies on the robustness of the individual assays and their clear discrimination, further enhancing screening capabilities in an attempt to block proteolytic events required for viral infectivity and spread.

scholarly journals The Root Cap Cuticle: A Cell Wall Structure for Seedling Establishment and Lateral Root Formation

Cell ◽  
2019 ◽  
Vol 176 (6) ◽  
pp. 1367-1378.e8 ◽  
Author(s):  
Alice Berhin ◽  
Damien de Bellis ◽  
Rochus B. Franke ◽  
Rafael A. Buono ◽  
Moritz K. Nowack ◽  
...  
Keyword(s):  
Cell Wall ◽  
Seedling Establishment ◽  
Lateral Root ◽  
Root Formation ◽  
Root Cap ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Lateral Root Formation ◽  
A Cell

scholarly journals Genetic transformation of Spizellomyces punctatus, a resource for studying chytrid biology and evolutionary cell biology

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Edgar M Medina ◽  
Kristyn A Robinson ◽  
Kimberly Bellingham-Johnstun ◽  
Giuseppe Ianiri ◽  
Caroline Laplante ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Migration ◽  
Life Cycle ◽  
Cell Biology ◽  
Nuclear Division ◽  
Animal Cells ◽  
Animal Evolution ◽  
Transgenic Lines ◽  
A Cell

Chytrids are early-diverging fungi that share features with animals that have been lost in most other fungi. They hold promise as a system to study fungal and animal evolution, but we lack genetic tools for hypothesis testing. Here, we generated transgenic lines of the chytrid Spizellomyces punctatus, and used fluorescence microscopy to explore chytrid cell biology and development during its life cycle. We show that the chytrid undergoes multiple rounds of synchronous nuclear division, followed by cellularization, to create and release many daughter ‘zoospores’. The zoospores, akin to animal cells, crawl using actin-mediated cell migration. After forming a cell wall, polymerized actin reorganizes into fungal-like cortical patches and cables that extend into hyphal-like structures. Actin perinuclear shells form each cell cycle and polygonal territories emerge during cellularization. This work makes Spizellomyces a genetically tractable model for comparative cell biology and understanding the evolution of fungi and early eukaryotes.

scholarly journals DETECTION OF SURFACE FORCES BY A CELL WALL MECHANOSENSOR

2020 ◽  
Author(s):  
Ramakanth Neeli-Venkata ◽  
Ruben Celador ◽  
Yolanda Sanchez ◽  
Nicolas Minc
Keyword(s):  
Cell Wall ◽  
Mechanical Stress ◽  
Dose Dependence ◽  
Surface Forces ◽  
Local Surface ◽  
Animal Cells ◽  
Regulatory Pathways ◽  
Surface Receptors ◽  
Tensile Forces ◽  
A Cell

ABSTRACTSurface receptors of animal cells, such as integrins, promote mechanosensation by forming local clusters as signaling hubs that transduce tensile forces. Walled cells of plants and fungi also feature surface sensors, with long extracellular domains embedded in their cell wall (CW), thought to detect CW injuries and promote repair. How these sensors probe surface forces remains unknown. By studying the conserved CW sensor Wsc1 in fission yeast, we uncovered the formation of micrometer-sized clusters at sites of local force application onto the CW. These clusters form within minutes of CW compression, in dose-dependence with mechanical stress and dissolve upon stress relaxation. Our data support that Wsc1 senses CW mechanical stress and accumulates to local sites of enhanced stress through its CW-associated extracellular WSC domain, independently of canonical polarity, trafficking and downstream CW regulatory pathways. Wsc1 may represent an autonomous module to detect and transduce local surface forces onto the CW.

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