The echinoderm axial organ is located centrally, at the meeting point of the
animals' "circulatory" systems. This, and its unusual histology, have prompted
the implication of a number of different functions for the organ, including
circulation, excretion and host defense. None of these have been definitively
proven. Claims that starfish...
Metabolic rate-temperature responses of three related
species of sea urchins were determined using oxygen consumption
rate measurements. The three species used were Strongylocentrotus
purpuratus, Strongylocentrotus franciscanus, and Allocentrotus
fragilis. All measurements were made using an oxygen
macro-electrode, physiological gas analyzer, and sealed respiratory
container. Two series of experiments--field-acclimatized and
temperature-acclimated--were...
Characteristics of bacterial clearance were investigated in the
purple sea urchin, Strongylocentrotus purpuratus (Echinodermata:
Echinoidea). Primary clearance kinetics were determined for three
bacteria, a marine Gram negative motile rod, a marine Gram positive non-motile
rod, and a fresh water fish pathogen, Aeromonas salmonicida.
Various doses of live bacteria were injected...
Allocentrotus fragilis (Jackson) was obtained from six stations
at depths of 100 to 1260 m on the continental shelf and upper slope off
Newport, Oregon.
Ages and growth rates of A. fragilis were determined by two
methods: 1) A procedure was developed to make growth zones of the
skeletal test...
Oögenesis in the sea urchin Strongylocentrotus purpuratus
was studied by histological methods and by histochemical techniques
for polysaccharides, lipids, and nucleic acids Urchins were
collected at Yaquina Head, Oregon at regular intervals between
April 1966 and March 1967. An attempt was made to correlate
seasonal variations in the coastal water...
Oogenesis in the sea urchin Strongylocentrotus purpuratus was
studied at the fine structural level, with special emphasis on the relationship
between the two main cell types within the ovary: the egg cells
and the nutritive phagocytes, or accessory cells. The nutritive
phagocytes are flagellated cells with extensive pseudopods which store...
The gastrula of the sea urchin Strongylocentrotus purpuratus
was dissociated into single cells. In culture these cells appeared
apolar, but reassembled into quasi-normal embryos composed of
structures with polarized cells. In this study emphasis was placed on
those morphological events coincident with the reestablishment of a
polar orientation within the...
Due to an interest in the evolutionary origins of
vertebrate mechanisms of immunorecognition, researchers
have frequently turned to deuterostome invertebrates as
model organisms. The purple sea urchin, Strongylocentrotus
purpuratus (Echinodermata: Echinoidea), was selected for
this study of putative immunorecognition molecules in a
deuterostome invertebrate.
Hemagglutinins, molecules which agglutinate red blood...