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

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

Bottom Line: 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.Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the 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

Related in: MedlinePlus

(A) Arrest of cytoplasmic streaming in P. bursaria by pressure (10-second intervals).P. bursaria at interphase arresting cytoplasmic streaming under pressure. Ma and Cv indicate macronucleus and contractile vacuole (broken lines), respectively. Scale bar, 20 µm. (B) Cytoplasmic streaming-dependent increase of the number of endosymbionts. A bar graph shows the number of endosymbionts (±S.D.) under pressure or non-pressure (control). The control value is the number of endosymbionts at intephase (stage 1) described in Fig. 1B. * means a statistical difference P<0.02.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2131778&req=5

pone-0001352-g002: (A) Arrest of cytoplasmic streaming in P. bursaria by pressure (10-second intervals).P. bursaria at interphase arresting cytoplasmic streaming under pressure. Ma and Cv indicate macronucleus and contractile vacuole (broken lines), respectively. Scale bar, 20 µm. (B) Cytoplasmic streaming-dependent increase of the number of endosymbionts. A bar graph shows the number of endosymbionts (±S.D.) under pressure or non-pressure (control). The control value is the number of endosymbionts at intephase (stage 1) described in Fig. 1B. * means a statistical difference P<0.02.

Mentions: We have shown that cytoplasmic streaming in P. bursaria is arrested both by pressure with glass coverslip spacing and by addition of microtubule drug nocodazole [3]. To further investigate roles of cytoplasmic streaming in P. bursaria, we determined the number of endosymbionts under pressure with a coverslip. As shown in Fig. 2A, the pressure arrested cytoplasmic streaming in P. bursaria at interphase, although the contractile vacuole (Cv) kept moving. Interestingly, endosymbionts started increasing within 2 hrs after initiating arrest of cytoplasmic streaming (Fig. 2B).


Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

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

(A) Arrest of cytoplasmic streaming in P. bursaria by pressure (10-second intervals).P. bursaria at interphase arresting cytoplasmic streaming under pressure. Ma and Cv indicate macronucleus and contractile vacuole (broken lines), respectively. Scale bar, 20 µm. (B) Cytoplasmic streaming-dependent increase of the number of endosymbionts. A bar graph shows the number of endosymbionts (±S.D.) under pressure or non-pressure (control). The control value is the number of endosymbionts at intephase (stage 1) described in Fig. 1B. * means a statistical difference P<0.02.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0001352-g002: (A) Arrest of cytoplasmic streaming in P. bursaria by pressure (10-second intervals).P. bursaria at interphase arresting cytoplasmic streaming under pressure. Ma and Cv indicate macronucleus and contractile vacuole (broken lines), respectively. Scale bar, 20 µm. (B) Cytoplasmic streaming-dependent increase of the number of endosymbionts. A bar graph shows the number of endosymbionts (±S.D.) under pressure or non-pressure (control). The control value is the number of endosymbionts at intephase (stage 1) described in Fig. 1B. * means a statistical difference P<0.02.
Mentions: We have shown that cytoplasmic streaming in P. bursaria is arrested both by pressure with glass coverslip spacing and by addition of microtubule drug nocodazole [3]. To further investigate roles of cytoplasmic streaming in P. bursaria, we determined the number of endosymbionts under pressure with a coverslip. As shown in Fig. 2A, the pressure arrested cytoplasmic streaming in P. bursaria at interphase, although the contractile vacuole (Cv) kept moving. Interestingly, endosymbionts started increasing within 2 hrs after initiating arrest of cytoplasmic streaming (Fig. 2B).

Bottom Line: 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.Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the 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
Related in: MedlinePlus