FEEDING AND DIGESTION IN THE TROPICAL SEA URCHIN DIADEMA ANTILLARUM PHILIPPI

1964 ◽  
Vol 42 (4) ◽  
pp. 549-557 ◽  
Author(s):  
John B. Lewis
Keyword(s):  
Calcium Carbonate ◽  
Digestive Tract ◽  
Sea Urchin ◽  
Feeding Activity ◽  
Diadema Antillarum ◽  
Early Evening ◽  
Tropical Sea

Diadema antillarum Philippi feeds principally upon algae. Feeding activity is greatest during the afternoon and early evening and food passes through the gut in 8–12 hours. Because of the considerable amount of calcium carbonate ingested with its food, the species is of importance as an erosive agent on reefs. Enzymes for the digestion of carbohydrates with α glucoside and β glucoside linkages are present in the gut. Secretion of carbohydrases takes place in the caecum. Proteases are secreted by the caecum and foregut. A weak lipase is present. The histology of the digestive tract is described.

THE CLAVIFORM PEDICELLARIAE AND THEIR STALK GLANDS IN THE TROPICAL SEA URCHIN DIADEMA ANTILLARUM PHILIPPI

1967 ◽  
Vol 45 (6) ◽  
pp. 1211-1214 ◽  
Author(s):  
John B. Lewis ◽  
Gail Saluja
Keyword(s):  
Sea Urchin ◽  
Acid Mucopolysaccharide ◽  
Diadema Antillarum ◽  
Tropical Sea

The morphology and histology of the stalk glands of the claviform pedicellariae of the sea urchin Diadema antillarum are described. Upon stimulation, the stalk glands secrete a non-sulfated acid mucopolysaccharide.

scholarly journals Sea urchin larvae utilize light for regulating the pyloric opening

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Junko Yaguchi ◽  
Shunsuke Yaguchi
Keyword(s):  
Signaling Pathway ◽  
Digestive Tract ◽  
Sea Urchin ◽  
Visual Information ◽  
Biological Activities ◽  
Regulatory System ◽  
Sister Group ◽  
Animal Evolution ◽  
Deuterostome Evolution ◽  
Visual Systems

Abstract Background Light is essential for various biological activities. In particular, visual information through eyes or eyespots is very important for most of animals, and thus, the functions and developmental mechanisms of visual systems have been well studied to date. In addition, light-dependent non-visual systems expressing photoreceptor Opsins have been used to study the effects of light on diverse animal behaviors. However, it remains unclear how light-dependent systems were acquired and diversified during deuterostome evolution due to an almost complete lack of knowledge on the light-response signaling pathway in Ambulacraria, one of the major groups of deuterostomes and a sister group of chordates. Results Here, we show that sea urchin larvae utilize light for digestive tract activity. We found that photoirradiation of larvae induces pyloric opening even without addition of food stimuli. Micro-surgical and knockdown experiments revealed that this stimulating light is received and mediated by Go(/RGR)-Opsin (Opsin3.2 in sea urchin genomes) cells around the anterior neuroectoderm. Furthermore, we found that the anterior neuroectodermal serotoninergic neurons near Go-Opsin-expressing cells are essential for mediating light stimuli-induced nitric oxide (NO) release at the pylorus. Our results demonstrate that the light>Go-Opsin>serotonin>NO pathway functions in pyloric opening during larval stages. Conclusions The results shown here will lead us to understand how light-dependent systems of pyloric opening functioning via neurotransmitters were acquired and established during animal evolution. Based on the similarity of nervous system patterns and the gut proportions among Ambulacraria, we suggest the light>pyloric opening pathway may be conserved in the clade, although the light signaling pathway has so far not been reported in other members of the group. In light of brain-gut interactions previously found in vertebrates, we speculate that one primitive function of anterior neuroectodermal neurons (brain neurons) may have been to regulate the function of the digestive tract in the common ancestor of deuterostomes. Given that food consumption and nutrient absorption are essential for animals, the acquirement and development of brain-based sophisticated gut regulatory system might have been important for deuterostome evolution.

scholarly journals On the Relation of Amorphous Calcium Carbonate and the Macromechanical Properties of Sea Urchin Spines

2020 ◽  
Vol 22 (4) ◽  
pp. 1900922 ◽  
Author(s):  
Christoph Lauer ◽  
Sebastian Haußmann ◽  
Patrick Schmidt ◽  
Carolin Fischer ◽  
Doreen Rapp ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Sea Urchin ◽  
Amorphous Calcium Carbonate ◽  
Sea Urchin Spines

Bacterial phylotypes associated with the digestive tract of the sea urchin Paracentrotus lividus and the ascidian Microcosmus sp.

2007 ◽  
Vol 33 (2) ◽  
pp. 84-91 ◽  
Author(s):  
A. Meziti ◽  
K. Ar. Kormas ◽  
M. -A. Pancucci-Papadopoulou ◽  
M. Thessalou-Legaki
Keyword(s):  
Digestive Tract ◽  
Sea Urchin ◽  
Paracentrotus Lividus ◽  
Bacterial Phylotypes

scholarly journals Transformation mechanism of amorphous calcium carbonate into calcite in the sea urchin larval spicule

2008 ◽  
Vol 105 (45) ◽  
pp. 17362-17366 ◽  
Author(s):  
Y. Politi ◽  
R. A. Metzler ◽  
M. Abrecht ◽  
B. Gilbert ◽  
F. H. Wilt ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Sea Urchin ◽  
Amorphous Calcium Carbonate ◽  
Transformation Mechanism
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