title: COLONY FORMATION AND SEXUAL MORPHOGENESIS IN THE COCCOLITHOPHORE PLEUROCHRYSIS SP. (HAPTOPHYTA)(1).
abstract: Pleurochrysis sp. formed two types of symmetrical, diploid colonies on solid media: (i) single-cell lineage (SCL) colonies and (ii) aggregation (AG) colonies. The first division of a single mother cell was asymmetric in ∼54% of SCL colonies. These colonies developed at a slower rate than AG colonies. Diffusible molecules released from the cells acted like morphogens enhancing formation of AG colonies; their influence on chemotaxis of aggregating cells was dependent on concentration of the inoculum. Nitrogen depletion of diploid colonies induced sexual morphogenesis and colony patterning into inner and outer regions. The smaller innermost cells were surrounded by outer larger cells. Developmental mechanisms of colony formation were examined in relation to the heteromorphic, haplo-diploid life cycle.
authors.affiliation: Department of Biology, City College of City University of New York, Convent Avenue at 138 Street, New York, New York 10031, USA.
authors.forename: Eva K
authors.initials: EK
authors.lastname: Hawkins
authors.affiliation: Department of Biology, City College of City University of New York, Convent Avenue at 138 Street, New York, New York 10031, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Biology, City College of City University of New York, Convent Avenue at 138 Street, New York, New York 10031, USA.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Fimiarz
keywords: Pleurochrysis; asymmetric cell division; chemotaxis; induction of colony patterning; sexual morphogenesis