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Micrasterias as a Model System in Plant Cell Biology.

Lütz-Meindl U - Front Plant Sci (2016)

Bottom Line: The review focuses particularly on cell wall formation and composition, dictyosomal structure and function, cytoskeleton control of growth and morphogenesis as well as on ionic regulation and signal transduction.It has been also shown in the recent years that Micrasterias is a highly sensitive indicator for environmental stress impact such as heavy metals, high salinity, oxidative stress or starvation.This review is intended to summarize and discuss the most important results obtained in Micrasterias in the last 20 years and to compare the results to similar processes in higher plant cells.

View Article: PubMed Central - PubMed

Affiliation: Plant Physiology Division, Cell Biology Department, University of Salzburg Salzburg, Austria.

ABSTRACT
The unicellular freshwater alga Micrasterias denticulata is an exceptional organism due to its complex star-shaped, highly symmetric morphology and has thus attracted the interest of researchers for many decades. As a member of the Streptophyta, Micrasterias is not only genetically closely related to higher land plants but shares common features with them in many physiological and cell biological aspects. These facts, together with its considerable cell size of about 200 μm, its modest cultivation conditions and the uncomplicated accessibility particularly to any microscopic techniques, make Micrasterias a very well suited cell biological plant model system. The review focuses particularly on cell wall formation and composition, dictyosomal structure and function, cytoskeleton control of growth and morphogenesis as well as on ionic regulation and signal transduction. It has been also shown in the recent years that Micrasterias is a highly sensitive indicator for environmental stress impact such as heavy metals, high salinity, oxidative stress or starvation. Stress induced organelle degradation, autophagy, adaption and detoxification mechanisms have moved in the center of interest and have been investigated with modern microscopic techniques such as 3-D- and analytical electron microscopy as well as with biochemical, physiological and molecular approaches. This review is intended to summarize and discuss the most important results obtained in Micrasterias in the last 20 years and to compare the results to similar processes in higher plant cells.

No MeSH data available.


Related in: MedlinePlus

Dictyosome of Micrasterias after exposure to CdSO4. (A–C) Images from FIB-SEM series. (D,E) Different views of corresponding 3-D reconstruction. Dictyosomal cisternae from cis- to trans-side: light blue to violet. Cisternae form balls at cis- and trans-side, abnormal ER displayed in dark blue. Scale bars are 1 μm. Reprinted with permission from Lütz-Meindl et al. (2015), Copyright© 2015 Royal Microscopical Society.
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Figure 10: Dictyosome of Micrasterias after exposure to CdSO4. (A–C) Images from FIB-SEM series. (D,E) Different views of corresponding 3-D reconstruction. Dictyosomal cisternae from cis- to trans-side: light blue to violet. Cisternae form balls at cis- and trans-side, abnormal ER displayed in dark blue. Scale bars are 1 μm. Reprinted with permission from Lütz-Meindl et al. (2015), Copyright© 2015 Royal Microscopical Society.

Mentions: Similar to the results obtained during KCl stress, evidence was provided for a non-autophagic degradation of dictyosomes by means of FIB-SEM tomography also in Cd treated cells (Lütz-Meindl et al., 2015). Figures 10A–E show TEM images and a 3-D reconstruction of a dictyosome during beginning disintegration. Both at the cis- and the trans-side detached cisternae form balls whereas the remaining middle cisternae of a stack appear bent and their rims are markedly lacerated. This indicates that stress induced dictyosomal degradation follows the same way after salt stress and Cd exposure (see also Figure 8). Also the kinetics of ROS production during Cd exposure of Micrasterias corresponds to that during salt stress (Andosch et al., 2012). ROS production increases by a factor 7 within the first 30 min of Cd stress and drops down almost to control level after 4 days.


Micrasterias as a Model System in Plant Cell Biology.

Lütz-Meindl U - Front Plant Sci (2016)

Dictyosome of Micrasterias after exposure to CdSO4. (A–C) Images from FIB-SEM series. (D,E) Different views of corresponding 3-D reconstruction. Dictyosomal cisternae from cis- to trans-side: light blue to violet. Cisternae form balls at cis- and trans-side, abnormal ER displayed in dark blue. Scale bars are 1 μm. Reprinted with permission from Lütz-Meindl et al. (2015), Copyright© 2015 Royal Microscopical Society.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940373&req=5

Figure 10: Dictyosome of Micrasterias after exposure to CdSO4. (A–C) Images from FIB-SEM series. (D,E) Different views of corresponding 3-D reconstruction. Dictyosomal cisternae from cis- to trans-side: light blue to violet. Cisternae form balls at cis- and trans-side, abnormal ER displayed in dark blue. Scale bars are 1 μm. Reprinted with permission from Lütz-Meindl et al. (2015), Copyright© 2015 Royal Microscopical Society.
Mentions: Similar to the results obtained during KCl stress, evidence was provided for a non-autophagic degradation of dictyosomes by means of FIB-SEM tomography also in Cd treated cells (Lütz-Meindl et al., 2015). Figures 10A–E show TEM images and a 3-D reconstruction of a dictyosome during beginning disintegration. Both at the cis- and the trans-side detached cisternae form balls whereas the remaining middle cisternae of a stack appear bent and their rims are markedly lacerated. This indicates that stress induced dictyosomal degradation follows the same way after salt stress and Cd exposure (see also Figure 8). Also the kinetics of ROS production during Cd exposure of Micrasterias corresponds to that during salt stress (Andosch et al., 2012). ROS production increases by a factor 7 within the first 30 min of Cd stress and drops down almost to control level after 4 days.

Bottom Line: The review focuses particularly on cell wall formation and composition, dictyosomal structure and function, cytoskeleton control of growth and morphogenesis as well as on ionic regulation and signal transduction.It has been also shown in the recent years that Micrasterias is a highly sensitive indicator for environmental stress impact such as heavy metals, high salinity, oxidative stress or starvation.This review is intended to summarize and discuss the most important results obtained in Micrasterias in the last 20 years and to compare the results to similar processes in higher plant cells.

View Article: PubMed Central - PubMed

Affiliation: Plant Physiology Division, Cell Biology Department, University of Salzburg Salzburg, Austria.

ABSTRACT
The unicellular freshwater alga Micrasterias denticulata is an exceptional organism due to its complex star-shaped, highly symmetric morphology and has thus attracted the interest of researchers for many decades. As a member of the Streptophyta, Micrasterias is not only genetically closely related to higher land plants but shares common features with them in many physiological and cell biological aspects. These facts, together with its considerable cell size of about 200 μm, its modest cultivation conditions and the uncomplicated accessibility particularly to any microscopic techniques, make Micrasterias a very well suited cell biological plant model system. The review focuses particularly on cell wall formation and composition, dictyosomal structure and function, cytoskeleton control of growth and morphogenesis as well as on ionic regulation and signal transduction. It has been also shown in the recent years that Micrasterias is a highly sensitive indicator for environmental stress impact such as heavy metals, high salinity, oxidative stress or starvation. Stress induced organelle degradation, autophagy, adaption and detoxification mechanisms have moved in the center of interest and have been investigated with modern microscopic techniques such as 3-D- and analytical electron microscopy as well as with biochemical, physiological and molecular approaches. This review is intended to summarize and discuss the most important results obtained in Micrasterias in the last 20 years and to compare the results to similar processes in higher plant cells.

No MeSH data available.


Related in: MedlinePlus