Limits...
Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

Takahashi T, Shirai Y, Kosaka T, Hosoya H - PLoS ONE (2007)

Bottom Line: Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming.Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle.Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biological Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.

ABSTRACT
A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells.

Show MeSH
The bar graph shows the number of endosymbionts (±S.D.) after treatment with nocodazole or with 1% DMSO.** means a statistical difference P<0.001.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2131778&req=5

pone-0001352-g003: The bar graph shows the number of endosymbionts (±S.D.) after treatment with nocodazole or with 1% DMSO.** means a statistical difference P<0.001.

Mentions: It has been known that a microtubule drug nocodazole arrests cytoplasmic streaming in green paramecia [3]. When nocodazole was added to arrest cytoplasmic streaming in P. bursaria (Movie S2), the number of endosymbionts also increased (Fig. 3). The paramecia treated with 6 µg/ml nocodazole had larger numbers of endosymbionts than paramecia treated with 3 µg/ml nocodazole (Fig. 3). The concentrations of nocodazole used completely arrested the growth of host paramecia (data not shown), while nocodazole used did not arrest growth of endosymbionts isolated from P. bursaria (Fig. S1). Thus, the results obtained show that arrest of cytoplasmic streaming induces proliferation of endosymbionts independently of host cell cycle.


Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

Takahashi T, Shirai Y, Kosaka T, Hosoya H - PLoS ONE (2007)

The bar graph shows the number of endosymbionts (±S.D.) after treatment with nocodazole or with 1% DMSO.** means a statistical difference P<0.001.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2131778&req=5

pone-0001352-g003: The bar graph shows the number of endosymbionts (±S.D.) after treatment with nocodazole or with 1% DMSO.** means a statistical difference P<0.001.
Mentions: It has been known that a microtubule drug nocodazole arrests cytoplasmic streaming in green paramecia [3]. When nocodazole was added to arrest cytoplasmic streaming in P. bursaria (Movie S2), the number of endosymbionts also increased (Fig. 3). The paramecia treated with 6 µg/ml nocodazole had larger numbers of endosymbionts than paramecia treated with 3 µg/ml nocodazole (Fig. 3). The concentrations of nocodazole used completely arrested the growth of host paramecia (data not shown), while nocodazole used did not arrest growth of endosymbionts isolated from P. bursaria (Fig. S1). Thus, the results obtained show that arrest of cytoplasmic streaming induces proliferation of endosymbionts independently of host cell cycle.

Bottom Line: Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming.Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle.Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biological Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.

ABSTRACT
A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells.

Show MeSH