PLASMOLYSIS, HECHTIAN STRAND FORMATION, AND LOCALIZED MEMBRANE‐WALL ADHESIONS IN THE DESMID, <i>CLOSTERIUM ACEROSUM</i> (CHLOROPHYTA)<sup>1</sup>

Domozych, David S.; Roberts, R.S.; Danyow, Carey; Flitter, Rebecca; Smith, Brennan K.; Providence, Kirwin M.

doi:10.1111/j.0022-3646.2003.03-033.x

Cited by 24 publications

(23 citation statements)

References 43 publications

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“…Certain studies indicate existence of microfilaments and MTs within the Hechtian strand (Lang-Pauluzzi, 2000; Lang-Pauluzzi and Gunning, 2000), whereas another study demonstrates their absence (Domozych et al, 2003). Consistent with our hypothesis that cytoskeleton inhibitors would disrupt the localization of LeAGP-1 on Hechtian strands, treatment of BY-2 cells with APM and cytochalasin-D relocalizes GFPLeAGP-1 in the periplasmic space.…”

Section: Discussionsupporting

confidence: 80%

Molecular Interactions of Arabinogalactan Proteins with Cortical Microtubules and F-Actin in Bright Yellow-2 Tobacco Cultured Cells

2006

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Arabinogalactan proteins (AGPs), a superfamily of plant hydroxyproline-rich glycoproteins, are present at cell surfaces. Although precise functions of AGPs remain elusive, they are widely implicated in plant growth and development. A well-characterized classical tomato (Lycopersicon esculentum) AGP containing a glycosylphosphatidylinositol plasma membrane anchor sequence was used here to elucidate functional roles of AGPs. Transgenic tobacco (Nicotiana tabacum) Bright Yellow-2 (BY-2) cells stably expressing green fluorescent protein (GFP)-LeAGP-1 were plasmolysed and used to localize LeAGP-1 on the plasma membrane and in Hechtian strands. Cytoskeleton disruptors and b-Yariv reagent (which binds and perturbs AGPs) were used to examine the role of LeAGP-1 as a candidate linker protein between the plasma membrane and cytoskeleton. This study used a two-pronged approach. First, BY-2 cells, either wild type or expressing GFP-microtubule (MT)-binding domain, were treated with b-Yariv reagent, and effects on MTs and F-actin were observed. Second, BY-2 cells expressing GFP-LeAGP-1 were treated with amiprophosmethyl and cytochalasin-D to disrupt MTs and F-actin, and effects on LeAGP-1 localization were observed. b-Yariv treatment resulted in terminal cell bulging, puncta formation, and depolymerization/disorganization of MTs, indicating a likely role for AGPs in cortical MT organization. b-Yariv treatment also resulted in the formation of thicker actin filaments, indicating a role for AGPs in actin polymerization. Similarly, amiprophosmethyl and cytochalasin-D treatments resulted in relocalization of LeAGP-1 on Hechtian strands and indicate roles for MTs and F-actin in AGP organization at the cell surface and in Hechtian strands. Collectively, these studies indicate that glycosylphosphatidylinositol-anchored AGPs function to link the plasma membrane to the cytoskeleton.

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Section: Discussionsupporting

confidence: 80%

Molecular Interactions of Arabinogalactan Proteins with Cortical Microtubules and F-Actin in Bright Yellow-2 Tobacco Cultured Cells

2006

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“…Vascular plants frequently form Hechtian strands, predominately at plasmodesmata, but this phenomenon is not so common in green algae. However, Domozych et al (2003) described Hechtian strands in plasmolysed Closterium acerosum cells, occurring only 30 min after the onset of plasmolysis in 12.5% sucrose (∼365 mM sucrose). Similar observations were made in the green alga Zygnema sp.…”

Section: Structural Consequences Of Plasmolysismentioning

confidence: 99%

“…As hypertonic solutions, either various salt solutions or osmotically active sugar solutions (e.g., sorbitol, mannitol) are used (Domozych et al 2003;Affenzeller et al 2009). Plants have the potential for osmoregulation, and data for green algae living in marine environments (e.g., Wegmann 1986;Oren 2007) are available, as well as several reports on salt stress causing plasmolysis in freshwater green algae (e.g., Meindl et al 1989;Affenzeller et al 2009;Darehshouri and Lütz-Meindl 2010;Gustavs et al 2010 and references therein).…”

Section: Introductionmentioning

confidence: 99%

Plasmolysis effects and osmotic potential of two phylogenetically distinct alpine strains of Klebsormidium (Streptophyta)

et al. 2011

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The osmotic potential and effects of plasmolysis were investigated in two different Klebsormidium strains from alpine habitats by incubation in 300-2,000 (3,000) mM sorbitol. Several members of this genus were previously found to tolerate desiccation in the vegetative state yet information was lacking on the osmotic potentials of these algae. The strains were morphologically determined as Klebsormidium crenulatum and Klebsormidium nitens. These species belong to distinct clades, as verified by phylogenetic analysis of the rbcL gene. K. crenulatum is part of to the K. crenulatum/mucosum ('F' clade) and K. nitens of the 'E2' clade. Plasmolysis occurred in K. crenulatum at 800 mM sorbitol (961 mOsmol kg(-1), Ψ = -2.09 MPa) and in K. nitens at 600 mM sorbitol (720 mOsmol kg(-1), Ψ = -1.67 MPa). These are extraordinarily high osmotic values (very negative osmotic potentials) compared with values reported for other green algae. In K. crenulatum, the maximum photosynthetic rate (Pmax) in the light-saturated range was 116 μmol O(2) h(-1) mg(-1) chl a. Incubation in 1,000 mM sorbitol decreased Pmax to 74.1% of the initial value, whereas 2,000 mM sorbitol (Ψ = -5.87 MPa) lead to an almost complete loss of oxygen production. In K. nitens, Pmax was 91 μmol O(2) h(-1) mg(-1) chl a under control conditions and incubation in 800 mM sorbitol did not decrease Pmax, 2,000 mM sorbitol decreased Pmax only to about 62.6% of the initial value whereas 3,000 mM sorbitol stopped oxygen evolution. This indicated a broader amplitude for photosynthesis in the examined strain of K. nitens. Control samples and samples plasmolysed for 3 h in 800 mM sorbitol (K. nitens), 1,000 mM sorbitol (K. crenulatum), or 2,000 mM sorbitol were investigated by transmission electron microscopy after chemical or high-pressure freeze fixation. In cells undergoing plasmolysis the protoplasts were retracted from the cell wall, the cytoplasm appeared dense, vacuoles were small and fragmented, and the cytoplasm was filled with ribosomes. Thin cytoplasmic strands were connected to the cell wall; 2,000 mM sorbitol increased the effect. The content of soluble carbohydrates in these two strains was investigated by HPLC, as this is one known mechanism for cells to maintain high osmotic pressure of the cytosol. Both Klebsormidium species contained diverse soluble carbohydrates, including a dominant mixed peak of unidentified oligosaccharides, and more minor amounts of raffinose, sucrose, glucose, xylose, galactose, mannose, inositol, fructose, glycerol, mannitol, and sorbitol. The total content of soluble carbohydrates was approximately 1.2% of the dry weight, indicating that this is not a major factor contributing to the high osmotic potential in these strains of Klebsormidium.

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“…This implies incredible evolutionary conservation and an early origin of the Hechtian Oscillator in unicellular Chloropycean algae such as Closterium [22] and Penium [23] as both exhibit tip growth with prominent Hechtian strands (Figure 1). Single cells remaining attached after cytokinesis evolved into simple linear filamentous algae as the first step towards multicellularity and its regulation.…”

Section: +mentioning

confidence: 99%

The Role of the Primary Cell Wall in Plant Morphogenesis

Lamport¹,

Li²,

Held³

et al. 2018

Preprint

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Morphogenesis remains a riddle, wrapped in a mystery, inside an enigma. It remains a formidable problem viewed from many different perspectives of morphology, genetics, and computational modelling. We propose a biochemical reductionist approach that shows how both internal and external physical forces contribute to plant morphogenesis via mechanical stress-strain transduction from the primary cell wall tethered to the plasma membrane by a specific arabinogalactan protein (AGP). The resulting stress vector with direction defined by Hechtian adhesion sites, has a magnitude of a few picoNewtons amplified by a hypothetical Hechtian growth oscillator. This paradigm shift involves stress activated plasma membrane Ca . Thus, as the immediate source of cytosolic Ca 2+ an AGP-Ca 2+ capacitor directs vectorial exocytosis of cell wall precursors and auxin efflux (PIN) proteins. In toto these components comprise the Hechtian Oscillator and also the gravisensor. Thus interdependent auxin and Ca 2+ morphogen gradients account for the predominance of AGPs. The size and location of a cell surface AGP-Ca 2+-capacitor is essential to differentiation and explains AGP correlation with all stages of morphogenetic patterning from embryogenesis to root and shoot. Finally, evolutionary origins of the Hechtian Oscillator in the unicellular Chlorophycean algae reflect the ubiquitous role of chemiosmotic proton pumps that preceded DNA at the dawn of life.

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PLASMOLYSIS, HECHTIAN STRAND FORMATION, AND LOCALIZED MEMBRANE‐WALL ADHESIONS IN THE DESMID, CLOSTERIUM ACEROSUM (CHLOROPHYTA)¹

Cited by 24 publications

References 43 publications

Molecular Interactions of Arabinogalactan Proteins with Cortical Microtubules and F-Actin in Bright Yellow-2 Tobacco Cultured Cells

Molecular Interactions of Arabinogalactan Proteins with Cortical Microtubules and F-Actin in Bright Yellow-2 Tobacco Cultured Cells

Plasmolysis effects and osmotic potential of two phylogenetically distinct alpine strains of Klebsormidium (Streptophyta)

The Role of the Primary Cell Wall in Plant Morphogenesis

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PLASMOLYSIS, HECHTIAN STRAND FORMATION, AND LOCALIZED MEMBRANE‐WALL ADHESIONS IN THE DESMID, CLOSTERIUM ACEROSUM (CHLOROPHYTA)1

Cited by 24 publications

References 43 publications

Molecular Interactions of Arabinogalactan Proteins with Cortical Microtubules and F-Actin in Bright Yellow-2 Tobacco Cultured Cells

Molecular Interactions of Arabinogalactan Proteins with Cortical Microtubules and F-Actin in Bright Yellow-2 Tobacco Cultured Cells

Plasmolysis effects and osmotic potential of two phylogenetically distinct alpine strains of Klebsormidium (Streptophyta)

The Role of the Primary Cell Wall in Plant Morphogenesis

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PLASMOLYSIS, HECHTIAN STRAND FORMATION, AND LOCALIZED MEMBRANE‐WALL ADHESIONS IN THE DESMID, CLOSTERIUM ACEROSUM (CHLOROPHYTA)¹