title: A secreted peptide growth factor, phytosulfokine, acting as a stimulatory factor of carrot somatic embryo formation.
abstract: Somatic embryogenesis of the carrot (Daucus carota L.) depends on a set of factors, some of which accumulate in culture medium (conditioned medium, CM). When embryogenic cell clusters were transferred to an embryo-inducing medium, addition of CM derived from somatic embryo culture markedly stimulated somatic embryo formation. The active principles were purified using a simple bioassay system and identified to be phytosulfokines (PSKs), sulfated oligopeptide growth factors originally isolated from a CM derived from asparagus (Asparagus officinalis L.) mesophyll culture. Quantification studies using a competition ELISA system employing an anti-PSK-alpha polyclonal antibody showed that PSK production might be related to growth of cells, rather than development of somatic embryos. Thus the stimulatory effect of PSK on somatic embryo formation might be due to promotion of cell proliferation.
authors.affiliation: Laboratory of Bioactive Natural Products Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Japan. i983006d@mbox.media.nagoya-u.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Hanai
authors.forename: T
authors.initials: T
authors.lastname: Matsuno
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Matsubayashi
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: H
authors.initials: H
authors.lastname: Kamada
authors.forename: Y
authors.initials: Y
authors.lastname: Sakagami
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D001681:Biological Assay / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D017077:Culture Media, Conditioned / Q000737:chemistry; D046508:Culture Techniques; D018552:Daucus carota / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D013058:Mass Spectrometry; D036361:Peptide Hormones; D010937:Plant Growth Regulators / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D010940:Plant Proteins / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D017077:Culture Media, Conditioned; C100975:PSK-alpha protein, plant; C101483:PSK-beta protein, plant; D036361:Peptide Hormones; D010937:Plant Growth Regulators; D010940:Plant Proteins; D015084:2,4-Dichlorophenoxyacetic Acid