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Nucleus Basal Body Connector of Dunaliella : Threshold Concentration of Calcium Necessary for in vitro Contraction *
Author(s) -
Merten P.,
Lechtreck K.F.,
Melkonian M.
Publication year - 1995
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1995.tb00824.x
Subject(s) - basal body , nucleus , calcium , dunaliella , contraction (grammar) , flagellate , biophysics , biology , anatomy , chemistry , microbiology and biotechnology , algae , biochemistry , flagellum , botany , endocrinology , organic chemistry , gene
Detergent‐isolated flagellar apparatuses of the flagellate green alga Dunaliella bioculata retain remnants of the nucleus (the karyoskeleton) which are linked to the basal bodies by the centrin‐containing nucleus basal body connectors (NBBC). Such complexes were subjected to different calcium concentrations (1 × 10 −9 M − 5 × 10 −4 M Ca 2+ ) and the distance between the basal bodies and the karyoskeleton was measured by light microscopy. The threshold concentration of Ca 2+ for NBBC contraction was determined to be around 5 × 10 −8 M Ca 2+ . At > 10 −7 M Ca 2+ NBBC were maximally contracted and the distance between the basal bodies and the karyoskeleton was only about 50% of the initial distance. Using a polyclonal antibody generated against centrin (Salisbury et al., 1984), the NBBC were visualized by indirect immunofluorescence in both the extended and contracted state. Our results demonstrate that in vitro contraction of centrin‐containing filaments in green algae is initiated at about the same free Ca 2+ concentration in three different centrin‐containing basal apparatus components (i.e. the distal connecting fibre, the flagellar transitional region and the NBBC).