scholarly journals Dynamic subcellular translocation of V‐type H + ‐ATPase is essential for biomineralization of the diatom silica cell wall

2019 ◽  
Vol 225 (6) ◽  
pp. 2411-2422 ◽  
Author(s):  
Daniel P. Yee ◽  
Mark Hildebrand ◽  
Martin Tresguerres
Keyword(s):  
Cell Wall ◽  
Subcellular Translocation ◽  
Silica Cell ◽  
Diatom Silica

scholarly journals Exocytosis of the silicified cell wall of diatoms involves extensive membrane disintegration

2021 ◽  
Author(s):  
Diede de Haan ◽  
Hadas Peled-Zehavi ◽  
Yoseph Addadi ◽  
Oz Ben Joseph ◽  
Lior Aram ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Membrane Dynamics ◽  
Cell Wall Formation ◽  
Mineral Phase ◽  
Wall Formation ◽  
Unicellular Algae ◽  
Silica Cell ◽  
Membrane Bound ◽  
Organelle Membrane

Diatoms are unicellular algae that are characterized by their silica cell walls. The silica elements form intracellularly in a membrane-bound organelle, and are exocytosed after completion. How diatoms maintain membrane homeostasis during the exocytosis of these large and rigid silica elements is a long-standing enigma. We studied membrane dynamics during cell wall formation and exocytosis in the diatom Stephanopyxis turris, using live-cell confocal microscopy and advanced electron microscopy. Our results provide detailed information on the ultrastructure and dynamics of the silicification process, showing that during cell wall formation, the organelle membranes tightly enclose the mineral phase, creating a precise mold of the delicate geometrical patterns. Surprisingly, during exocytosis of the mature silica elements, the proximal organelle membrane becomes the new plasma membrane, and the distal membranes gradually disintegrate into the extracellular space without any noticeable endocytic retrieval or extracellular repurposing. These observations suggest that diatoms evolved an extraordinary exocytosis mechanism in order to secrete their cell wall elements.

scholarly journals Herbicide effects on freshwater benthic diatoms: Induction of nucleus alterations and silica cell wall abnormalities

2008 ◽  
Vol 88 (1) ◽  
pp. 88-94 ◽  
Author(s):  
T. Debenest ◽  
J. Silvestre ◽  
M. Coste ◽  
F. Delmas ◽  
E. Pinelli
Keyword(s):  
Cell Wall ◽  
Benthic Diatoms ◽  
Silica Cell ◽  
Herbicide Effects

Nanoscale control of silica morphology and three-dimensional structure during diatom cell wall formation

2006 ◽  
Vol 21 (10) ◽  
pp. 2689-2698 ◽  
Author(s):  
Mark Hildebrand ◽  
Evelyn York ◽  
Jessica I. Kelz ◽  
Aubrey K. Davis ◽  
Luciano G. Frigeri ◽  
...  
Keyword(s):  
Cell Wall ◽  
Three Dimensional ◽  
Thalassiosira Pseudonana ◽  
Dimensional Structure ◽  
Advanced Imaging ◽  
Form Complex ◽  
Process Understanding ◽  
Silica Cell ◽  
Unique Approach ◽  
Synthetic Approaches

We present a unique approach combining biological manipulation with advanced imaging tools to examine silica cell wall synthesis in the diatom Thalassiosira pseudonana. The innate capabilities of diatoms to form complex 3D silica structures on the nano- to micro-scale exceed current synthetic approaches because they use a fundamentally different formation process. Understanding the molecular details of the process requires identifying structural intermediates and correlating their formation with genes and proteins involved. This will aid in development of approaches to controllably alter structure, facilitating the use of diatoms as a direct source of nanostructured materials. In T. pseudonana, distinct silica morphologies were observed during formation of different cell wall substructures, and three different scales of structural organization were identified. At all levels, structure formation correlated with optimal design properties for the final product. These results provide a benchmark of measurements and new insights into biosilicification processes, potentially also benefiting biomimetic approaches.

scholarly journals Structural evidence for extracellular silica formation by diatoms

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Boaz Mayzel ◽  
Lior Aram ◽  
Neta Varsano ◽  
Sharon G. Wolf ◽  
Assaf Gal
Keyword(s):  
Cell Wall ◽  
Electron Tomography ◽  
Nanometer Scale ◽  
Diatom Species ◽  
Silica Precipitation ◽  
Prevailing Paradigm ◽  
Silica Cell ◽  
Cryo Electron Tomography ◽  
Intracellular Process

AbstractThe silica cell wall of diatoms, a widespread group of unicellular microalgae, is an exquisite example for the ability of organisms to finely sculpt minerals under strict biological control. The prevailing paradigm for diatom silicification is that this is invariably an intracellular process, occurring inside specialized silica deposition vesicles that are responsible for silica precipitation and morphogenesis. Here, we study the formation of long silicified extensions that characterize many diatom species. We use cryo-electron tomography to image silica formation in situ, in 3D, and at a nanometer-scale resolution. Remarkably, our data suggest that, contradictory to the ruling paradigm, these intricate structures form outside the cytoplasm. In addition, the formation of these silica extensions is halted at low silicon concentrations that still support the formation of other cell wall elements, further alluding to a different silicification mechanism. The identification of this unconventional strategy expands the suite of mechanisms that diatoms use for silicification.

scholarly journals Shedding light on biosilica morphogenesis by comparative analysis of the silica-associated proteomes from three diatom species

2021 ◽  
Author(s):  
Alastair Skeffington ◽  
Marc Gentzel ◽  
Andre Ohara ◽  
Alexander Milentyev ◽  
Christoph Heintze ◽  
...  
Keyword(s):  
Cell Walls ◽  
Thalassiosira Pseudonana ◽  
Sequence Motifs ◽  
Diatom Species ◽  
Sequence Alignments ◽  
Bioinformatics Analyses ◽  
Silica Cell ◽  
Species Specific ◽  
Diatom Silica

Morphogenesis of the intricate patterns of diatom silica cell walls is a protein-guided process, yet to date only very few such silica morphogenetic proteins have been identified. Therefore, it is unknown whether all diatoms share conserved proteins of a basal silica forming machinery, and whether unique proteins are responsible for the morphogenesis of species specific silica patterns. To answer these questions, we extracted proteins from the silica of three diatom species (Thalassiosira pseudonana, Thalassiosira oceanica and Cyclotella cryptica) by complete demineralization of the cell walls. LC-MS/MS analysis of the extracts identified 92 proteins that we name 'Soluble Silicome Proteins' (SSPs). Surprisingly, no SSPs are common to all three species, and most SSPs showed very low similarity to one another in sequence alignments. In depth bioinformatics analyses revealed that SSPs can be grouped into distinct classes bases on short unconventional sequence motifs whose functions are yet unknown. The results from in vivo localization of selected SSPs indicates that proteins, which lack sequence homology but share unconventional sequence motifs may exert similar functions in the morphogenesis of the diatom silica cell wall.

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