title: Protoplast formation of the coccolithophorid Pleurochrysis haptonemofera in hypoosmotic K+ solution: shedding of the coccosphere and regrowth of the protoplast in normal medium.
abstract: Both coccolith-bearing cells (C-cells) and naked cells (N-cells) of the coccolithophorid Pleurochrysis haptonemofera can grow in salinities of more than 7 per thousand (about 20% of a "normal" sea water salinity [35 per thousand]), with the highest growth rates in salinities of more than 14 per thousand. Microscopic observations of cells suspended in 100 mM NaCl (7 per thousand) showed that, while N-cells were swelling uniformly all over the cell surface, C-cells were bulging the plasma membrane from the hole of the coccosphere at the apical (flagellar) pole of the cell. Effects of several cations and anions on the morphological change of C-cells under hypoosmotic pressure were investigated. When 100 mM K(+) was used, protoplasts were released from the coccosphere completely in almost all the cells. This phenomenon was shown with K(+) most effectively. The protoplasts could grow in the fresh medium and form the first coccolith within 9 h.
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Takayanagi
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Hirokawa
authors.forename: Maki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Toshichika
authors.initials: T
authors.lastname: Ohki
authors.forename: Shoko
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Mikio
authors.initials: M
authors.lastname: Tsuzuki
mesh_terms: D002462:Cell Membrane / Q000187:drug effects; D003470:Culture Media / Q000737:chemistry; D056890:Eukaryota / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology*; D009997:Osmotic Pressure; D011189:Potassium Chloride / Q000494:pharmacology*; D011523:Protoplasts / Q000502:physiology*; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology; D012965:Sodium Chloride / Q000494:pharmacology; D013997:Time Factors
chemical_list: D003470:Culture Media; D012965:Sodium Chloride; D011189:Potassium Chloride