Some chemical constituents of the digestive gland of the sea hare Aplysia californica

1976 ◽  
Vol 41 (14) ◽  
pp. 2461-2465 ◽  
Author(s):  
Chris. Ireland ◽  
Martha O. Stallard ◽  
D. John. Faulkner ◽  
Janet. Finer ◽  
Jon. Clardy
Keyword(s):  
Digestive Gland ◽  
Chemical Constituents ◽  
Aplysia Californica ◽  
Sea Hare

scholarly journals Role of the Digestive Gland in Ink Production in Four Species of Sea Hares: An Ultrastructural Comparison

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Jeffrey S. Prince ◽  
Paul Micah Johnson
Keyword(s):  
Digestive Gland ◽  
Common Ancestor ◽  
Aplysia Californica ◽  
Digestive Cell ◽  
Digestive Cells ◽  
Sea Hare ◽  
Red Algal ◽  
The Common ◽  
Algal Chloroplast

The ultrastructure of the digestive gland of several sea hare species that produce different colored ink (Aplysia californicaproduces purple ink,A. julianawhite ink,A. parvulaboth white and purple ink, whileDolabrifera dolabriferaproduces no ink at all) was compared to determine the digestive gland’s role in the diet-derived ink production process. Rhodoplast digestive cells and their digestive vacuoles, the site of digestion of red algal chloroplast (i.e., rhodoplast) inA. californica, were present and had a similar ultrastructure in all four species. Rhodoplast digestive cell vacuoles either contained a whole rhodoplast or fragments of one or were empty. These results suggest that the inability to produce colored ink in some sea hare species is not due to either an absence of appropriate digestive machinery, that is, rhodoplast digestive cells, or an apparent failure of rhodoplast digestive cells to function. These results also propose that the digestive gland structure described herein occurred early in sea hare evolution, at least in the common ancestor to the generaAplysiaandDolabrifera. Our data, however, do not support the hypothesis that the loss of purple inking is a synapomorphy of the white-ink-producing subgenusAplysia.

scholarly journals Ultrastructural Comparison of Processing of Protein and Pigment in the Ink Gland of Four Species of Sea Hares

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Jeffrey S. Prince ◽  
Paul Micah Johnson
Keyword(s):  
Digestive Gland ◽  
Cell Membranes ◽  
Aplysia Californica ◽  
Protein Storage ◽  
Sea Hare ◽  
Storage Vesicles ◽  
Algal Pigment ◽  
Red Algal

The ink glands of four sea hare species (Aplysia californica,A. parvula,A. juliana, andDolabrifera dolabrifera) were compared to determine where ink protein is synthesized, how it is incorporated into protein storage vesicles, and the degree of variation in the structure of the ink gland. Ink protein was synthesized in RER cells and stored in amber and white vesicles. Lack of competent RER cells in the ink gland ofD. dolabriferawas correlated with the absence of ink protein. Ink protein had similar characteristics in all threeAplysiaspecies but, again, it was absent inD. dolabrifera. Its uptake involved pinocytosis by protein vesicle cell membranes. Granulate cells showed little variation in structure among the four species, the opposite was the case for RER cells. The conversion of the red algal pigment, phycoerythrin, to phycoerythrobilin (PEB) occurs in the digestive gland but the change of PEB to aplysioviolin (APV), the form of pigment released by the ink gland, occurs in the ink gland itself by both granulate cells and pigment vesicles. The literature describes five types of vesicles based upon color and contents in the ink gland of these four species. We report only three types of vesicle: colored (purple), protein (white and amber), and transparent (includes clear vesicles).

scholarly journals Defensive ink pigment processing and secretion in Aplysia californica: concentration and storage of phycoerythrobilin in the ink gland.

1998 ◽  
Vol 201 (10) ◽  
pp. 1595-1613 ◽  
Author(s):  
J Prince ◽  
T G Nolen ◽  
L Coelho
Keyword(s):  
Endoplasmic Reticulum ◽  
Digestive Gland ◽  
Aplysia Californica ◽  
Cell Types ◽  
Coated Vesicles ◽  
Coated Vesicle ◽  
Cell Type ◽  
Digestive Cells ◽  
Red Algal ◽  
Green Seaweed

The marine snail Aplysia californica obtains its defensive ink exclusively from a diet of red seaweed. It stores the pigment (phycoerythrobilin, the red algal photosynthetic pigment, r-phycoerythrin, minus its protein) in muscular ink-release vesicles within the ink gland. Snails fed a diet of green seaweed or romaine lettuce do not secrete ink and their ink-release vesicles are largely devoid of ink. Successive activation of individual ink-release vesicles by ink motor neurons causes them to secrete approximately 55 % of their remaining ink (similar to the percentage of ink reserves released from the intact gland). The peripheral activation of vesicles appears to be cholinergic: 70 % of isolated vesicles were induced to squeeze ink from their valved end by solutions of acetylcholine at concentrations of 0.5 mmol l-1 or below. Ultrastructural analysis commonly found three cell types in the ink gland. The RER cells, the most numerous, were characterized by an extensive rough endoplasmic reticulum with greatly distended cisternae. This cell type is probably the site for synthesis of the high molecular mass protein of secreted ink. The granulate cells, less common than RER cells, had nuclear and cell areas significantly larger than those of RER cells. In addition, granulate cells of red-algal-fed snails had 4-14 vacuoles that contained electron-dense material with staining characteristics similar to that of ink in mature ink-release vesicles. The granulate cell's plasma membrane was regularly modified into grated areas, which both localized and expanded the surface area for coated vesicle formation and provided a sieve structure that prevented large particles in the hemolymph either from being taken up by, or from occluding, the coated vesicles. Electron-dense particles within coated vesicles were similar in size to those in granulate vacuoles but larger (on average by approximately 1 nm) than those that make up the ink. In green-seaweed-fed snails, granulate cells and their vacuoles were present but the vacuoles were empty. The third cell type, the vesicle cell, expands markedly, with its nucleus enlarging concurrent with cell growth until it is on average 50 times larger in cross-sectional area than the nuclei of either RER or granulate cells; the cytoplasm eventually becomes filled with ink, which obscures the mitochondria, vacuoles and nucleus. Continued cell expansion ceases with the appearance of an encircling layer of muscle and 1-3 layers of cells of unknown origin, thereby becoming the ink-release vesicle itself. The absorption spectra of the soluble contents of mature ink-release vesicles from snails fed red algae had peaks characteristic of the red algal pigment r-phycoerythrin or/and phycoerythrobilin. Immunogold localization of r-phycoerythrin showed no statistical difference in the amount of label within the ink-release vesicles, RER or granulate cell types. Furthermore, there was no localization of phycoerythrin immunoreactivity within the various cellular compartments of either the RER or granulate cells (nucleus, endoplasmic reticulum, mitochondria, vacuoles). Immunogold labeling in the ink gland ranged from 11 to 16 % of that for the digestive vacuoles of the rhodoplast digestive cells lining the tubules of the digestive gland. Our observations suggest (a) that the main form of the ink pigment in the gland is phycoerythrobilin or/and a non-antigenic form of phycoerythrin, and (b) that separation of the bilin from phycoerythrin (or its modification so that it is no longer antigenic) occurs before it reaches the ink gland, probably within the vacuoles of the rhodoplast digestive cells of the digestive gland. We propose the following model. The ink pigment, phycoerythrobilin, is cleaved from its protein in rhodoplast digestive vacuoles in the digestive gland. (ABSTRACT TRUNCATED)

Processing of defensive pigment in Aplysia californica: acquisition, modification and mobilization of the red algal pigment, r-phycoerythrin by the digestive gland.

1998 ◽  
Vol 201 (3) ◽  
pp. 425-438 ◽  
Author(s):  
L Coelho ◽  
J Prince ◽  
T G Nolen
Keyword(s):  
Digestive Gland ◽  
Photosynthetic Pigment ◽  
Aplysia Californica ◽  
Cell Types ◽  
The Body ◽  
Digestive Cell ◽  
Digestive Cells ◽  
Red Seaweeds ◽  
Red Algal ◽  
Green Seaweed

The marine snail Aplysia californica obtains its purple defensive ink exclusively from the accessory photosynthetic pigment r-phycoerythrin, which is found in the red seaweeds of its diet. The rhodoplast digestive cell, one of three types of cell lining the tubules of the digestive gland, appears to be the site of catabolism of red algal chloroplasts (rhodoplasts) since thylakoid membranes, including phycobilisome-sized membrane-associated particles, were found within the large digestive vacuoles of this cell. Immunogold localization showed that there was a statistically significant occurrence of the red algal phycobilisome pigment r-phycoerythrin within these rhodoplast digestive vacuoles, but not in other compartments of this cell type (endoplasmic reticulum, mitochondria, nucleus) or in other tissues (abdominal ganglion). Immunogold analysis also suggested that the rhodoplast vacuole is the site for additional modification of r-phycoerythrin, which makes it non-antigenic: the chromophore is either cleaved from its biliprotein or the biliprotein is otherwise modified. The hemolymph had spectrographic absorption maxima typical of the protein-free chromophore (phycoerythrobilin) and/or r-phycoerythrin, but only when the animal had been feeding on red algae. Rhodoplast digestive cells and their vacuoles were not induced by the type of food in the diet: snails fed green seaweed and animals fed lettuce had characteristic rhodoplast cells but without the large membranous inclusions (rhodoplasts) or phycobilisome-like granules found in animals fed red seaweed. Two additional cell types lining the tubules of the digestive gland were characterized ultrastructurally: (1) a club-shaped digestive cell filled with electron-dense material, and (2) a triangular 'secretory' cell devoid of storage material and calcium carbonate. The following model is consistent with our observations: red algal rhodoplasts are freed from algal cells in the foregut and then engulfed by rhodoplast digestive cells in the tubules of the digestive diverticula, where they are digested in membrane-bound vacuoles; r-phycoerythrin is released from phycobilisomes on the rhodoplast thylakoids and chemically modified before leaving the digestive vacuole and accumulating in the hemolymph; the pigment then circulates throughout the body and is concentrated in specialized cells and vesicles of the ink gland, where it is stored until secreted in response to certain predators.

Dietary metal toxicity to the marine sea hare, Aplysia californica

2015 ◽  
Vol 174-175 ◽  
pp. 54-64 ◽  
Author(s):  
Tayler A. Jarvis ◽  
Thomas R. Capo ◽  
Gretchen K. Bielmyer-Fraser
Keyword(s):  
Metal Toxicity ◽  
Aplysia Californica ◽  
Sea Hare

Bacterial clearance in the California sea hare, Aplysia californica

1971 ◽  
Vol 18 (2) ◽  
pp. 227-239 ◽  
Author(s):  
Gilbert B. Pauley ◽  
Stuart M. Krassner ◽  
Faylla A. Chapman
Keyword(s):  
Aplysia Californica ◽  
Bacterial Clearance ◽  
Sea Hare
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