Frustule morphogenesis of raphid pennate diatom Encyonema ventricosum (Agardh) Grunow

Bedoshvili, Yekaterina D.; Гнеушева, К. В.; Popova, Maria; Avezova, T.N.; Arsentyev, Kirill Yu; Likhoshway, Yelena V.

doi:10.1007/s00709-017-1199-4

Cited by 15 publications

(9 citation statements)

References 30 publications

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“…It is possible that morphogenesis is partially controlled by microtubule-mediated vesicular transport (Parkinson et al, 1999). The involvement of vesicular transport in valve morphogenesis is well supported (Dawson, 1973; Schmid and Schultz, 1979; Bedoshvili et al, 2018). It is possible that vesicles carry silification agents both as cargo (e.g.…”

Section: Discussionmentioning

confidence: 96%

Anomalies in the valve morphogenesis of the centric diatom alga Aulacoseira islandica caused by microtubule inhibitors

et al. 2018

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Of all unicellular organisms possessing a cell wall, diatoms are the most adept at micro- and nanoscale embellishment of their frustules. Elements of their cell walls are formed inside the cell under cytoskeletal control. In this work, we used laser scanning microscopy and electron microscopy to describe the major stages of cell wall formation in the centric diatom algae Aulacoseira islandica and to study the effect of various microtubule inhibitors on the morphogenesis of frustule elements. Our results show that colchicine inhibits karyokinesis and cytokinesis in A. islandica colonies. In contrast, valve morphogenesis is changed, rather than inhibited altogether. In normal cells, this process starts simultaneously in both daughter cells, beginning with the formation of two adjacent discs that later become valve faces and connecting spines. Under colchicine treatment, however, the cleavage furrow is blocked and a single lateral valve forms on the side of the cylindrical frustule. As a result, a single hollow pipe forms instead of two separate drinking glass-shaped frustules; such pipes can form up to 35% of all forming frustules. Colchicine inhibits the formation of connecting spines, whereas paclitaxel causes spines to form a complex, branching shape. At the same time, inhibitors do not affect the formation of areolae (openings) in the frustule. We discuss the possibility that various processes of the diatom frustule morphogenesis are controlled by two different mechanisms: membrane-related micromorphogenesis and cytoskeleton-mediated macromorphogenesis.

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Section: Discussionmentioning

confidence: 96%

Anomalies in the valve morphogenesis of the centric diatom alga Aulacoseira islandica caused by microtubule inhibitors

et al. 2018

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“…The two histograms show the two different vesicle sizes that were simulated. forward few models for silica cell wall exocytosis in diatoms that are reproduced here (14,(16)(17)(18)(19)(20)(21)(22)(23). One scenario suggests that the newly formed valve is externalized through formation of a new plasma membrane underneath it (A).…”

Section: Total Duration Of the Exocytosis/endocytosis Processmentioning

confidence: 99%

“…Early ultrastructural studies brought forward several models for silica cell wall exocytosis in diatoms 15,[17][18][19][20][21][22][23][24] (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

“…The new valve covers as much as half of the total cell surface and thus the surface area of the SDV membrane is similar to the entire plasma membrane, therefore, fusion with the SDV membrane would lead to an almost instantaneous doubling of the plasma membrane area. 4 While former studies have brought forward several hypotheses for silica cell wall exocytosis in diatoms (14,(16)(17)(18)(19)(20)(21)(22)(23); Fig. S2), significant experimental challenges have hindered further progress.…”

Section: Introductionmentioning

confidence: 99%

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

Haan

Peled-Zehavi

Addadi³

et al. 2021

Preprint

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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.

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“…In other studies, tubulin has been shown to be involved during morphogenesis, and microtubules appear to form underlying layers during the formation of valves [ 60 , 61 ] and other specialized structures [ 56 , 57 ]. The role of microtubules is likely not limited to defining formations of structure; they are also likely to be involved in intracellular vesicular transport [ 50 , 62 , 63 ]. A hypothesis was put forward about the specific localization of aquaporins in silicalemma by MTs during the morphogenesis of silica structures [ 64 ].…”

Section: Introductionmentioning

confidence: 99%

Molecular Evolution of Tubulins in Diatoms

Khabudaev

Petrova

Bedoshvili

et al. 2022

IJMS

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Microtubules are formed by α- and β-tubulin heterodimers nucleated with γ-tubulin. Tubulins are conserved eukaryotic proteins. Previously, it was shown that microtubules are involved in diatom silica frustule morphogenesis. Diatom frustules are varied, and their morphology is species-specific. Despite the attractiveness of the problem of elucidating the molecular mechanisms of genetically programmed morphogenesis, the structure and evolution of diatom tubulins have not been studied previously. Based on available genomic and transcriptome data, we analyzed the phylogeny of the predicted amino acid sequences of diatom α-, β- and γ-tubulins and identified five groups for α-tubulins, six for β-tubulins and four for γ-tubulins. We identified characteristic amino acids of each of these groups and also analyzed possible posttranslational modification sites of diatom tubulins. According to our results, we assumed what changes occurred in the diatom tubulin structures during their evolution. We also identified which tubulin groups are inherent in large diatom taxa. The similarity between the evolution of diatom tubulins and the evolution of diatoms suggests that molecular changes in α-, β- and γ-tubulins could be one of the factors in the formation of a high morphological diversity of diatoms.

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Frustule morphogenesis of raphid pennate diatom Encyonema ventricosum (Agardh) Grunow

Cited by 15 publications

References 30 publications

Anomalies in the valve morphogenesis of the centric diatom alga Aulacoseira islandica caused by microtubule inhibitors

Anomalies in the valve morphogenesis of the centric diatom alga Aulacoseira islandica caused by microtubule inhibitors

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

Molecular Evolution of Tubulins in Diatoms

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