Calcium transients during early development in echinoderms and teleosts

Journal Article · Sat Oct 01 04:00:00 EDT 1977 · Biol. Bull.; (United States)

OSTI ID:5206442

Kiehart, D P; Reynolds, G T; Eisen, A

To visualize increased cytoplasmic levels of free Ca/sup + +/ during various processes in early development, eggs from the sea urchin Lytechinus variegatus and the teleost Oryzias latipes (Medaka), pre-microinjected with the Ca/sup + +/-sensitive luminescent protein aequorin, were observed during fertilization, mitosis, and cleavage using a microscope image intensification system. The light from the image intensifier (gain ca. 10/sup 6/) was observed directly and recorded on Polaroid 3000 and 10,000 film. While luminescence was observed during fertilization, none was observed during mitosis or cleavage. Single Lytechinus eggs gave sufficient Ca/sup + +/-aequorin luminescence to permit a sequence of photographs during the activation process. The time resolution was limited to ca 5 sec. No wave of light was observed to traverse the eggs. Instead, the entire surface was emitting light within 7 sec of fertilization and continued to luminesce for longer than 60 sec. This is in contrast to the wave of Ca/sup + +/ release observed in Medaka (Gilkey et al., 1977, Biophys. J., 17: 277a). The threshold for detectability of Ca/sup + +/-aequorin luminescence in artificial sea urchin ''cytoplasms'' containing physiological levels of Mg/sup + +/ was ca. 5 to 10 micromolar Ca/sup + +/. Therefore, during fertilization in sea urchins the Ca/sup + +/ concentration increases to greater than 5 micromolar, but during mitosis and cleavage, no increase in free Ca/sup + +/ above 5 micromolar is observed. It takes ca. 10 to 20 sec for the wave of cortical vesicle breakdown to traverse the sea urchin egg, yet the entire surface of the egg was luminescing in less than 7 sec. It is concluded that while Ca/sup + +/ may be necessary for the cortical reaction, its increase in concentration alone is not sufficient to cause cortical vesicle breakdown.

• OSTI ID: 5206442
• Journal Information: Biol. Bull.; (United States), Journal Name: Biol. Bull.; (United States) Vol. 153:2; ISSN BIBUA
• Country of Publication: United States
• Language: English

Related Subjects

550500* -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METALS
ANIMALS
AQUATIC ORGANISMS
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CALCIUM
CELL CONSTITUENTS
CELL DIVISION
CENTRAL NERVOUS SYSTEM
CEREBRAL CORTEX
CEREBRUM
CYTOPLASM
EGGS
ELEMENTS
FISHES
KINETICS
MAGNESIUM
METALS
NERVOUS SYSTEM
ONTOGENESIS
ORGANS
REACTION KINETICS
VERTEBRATES