Studies of protistan mineralization. I. Kinetics of coccolith secretion in Hymenomonas carterae
Williams, D.C.
Calcified Tissue Research 16(3): 227-237
1974
ISSN/ISBN: 0008-0594 PMID: 4614889 Document Number: 80018
The calcified body scale (coccolith) of the unicellular marine alga Hymenomonas carterae is composed of two morphologically distinct calcite elements which alternate about the perimeter of a complex, elliptical organic base. The coccoliths of Hymenomonas are formed intracellularly in a precise and orderly sequence of events within the single Golgi apparatus of the alga and then secreted to the anterior cell surface. This study demonstrates that the kinetics of this calcification-secretion process can be reproducibly determined by morphological means. Under standardized conditions, coccoliths are secreted at a rate of about ten per hour. In the absence of light this rate is significantly reduced. The procedure described for determining the kinetics of coccolith secretion in Hymenomonas provides a simple, precise method for evaluating the results of experimental manipulation of this calcification-secretion system.