Direct innervation of the mantle edge gland by neurosecretory axons in Helisoma duryi (Mollusca: Pulmonata)

1976 ◽  
Vol 171 (3) ◽  
Author(s):  
A.S.M. Saleuddin ◽  
R.M. Dillaman
Keyword(s):  
Helisoma Duryi ◽  
Mantle Edge

Histochemical studies of dopa oxidase and peroxidase in the mantle-edge of the freshwater gastropod, Helisoma duryi eudiscus (Pilsbry)

1968 ◽  
Vol 46 (2) ◽  
pp. 165-167 ◽  
Author(s):  
S. P. Kapur ◽  
M. A. Gibson
Keyword(s):  
Positive Reaction ◽  
Protein Component ◽  
Negative Reaction ◽  
Structural Proteins ◽  
Freshwater Gastropod ◽  
Helisoma Duryi ◽  
Mantle Edge ◽  
Dopa Oxidase ◽  
Oxidase Reaction

The mantle-edge gland produces the highly tanned, densely fibrous periostracum, and the cubocolumnar cells contribute to the deposition of the less highly tanned matrix of the inner shell layers. The mantle-edge gland gives positive reactions for dopa oxidase and peroxidase, but does not contain melanin. The cubocolumnar cells reveal a positive reaction for dopa oxidase, possess numerous melanin granules, and exhibit a negative reaction for peroxidase. It is suggested that quinones may contribute to the process of tanning and hardening of the structural proteins of the shell. The dopa oxidase reaction within the cubocolumnar cells indicates the presence of tyrosine and suggests that these cells are capable of producing quinones to color and harden the protein component of the inner shell layers. It also explains the abundance of melanin granules within these cells. Within the mantle-edge gland, it is suggested that the peroxidase inhibits the formation of melanin from dopa quinone, and peroxidase, by accentuating quinone production, may cause further hardening of the periostracum.

A histochemical study of the development of the mantle-edge and shell in the freshwater gastropod, Helisoma duryi eudiscus (Pilsbry)

1968 ◽  
Vol 46 (3) ◽  
pp. 481-491 ◽  
Author(s):  
S. P. Kapur ◽  
M. A. Gibson
Keyword(s):  
Alkaline Phosphatase ◽  
Ribonucleic Acid ◽  
Ground Substance ◽  
Freshwater Gastropod ◽  
Helisoma Duryi ◽  
Yellow Body ◽  
Golgi Element ◽  
Mantle Edge ◽  
Extrapallial Fluid ◽  
Distal Border

Glycogen and ribonucleic acid are present in the mantle-edge during the prehatching period and in the adult. The cubocolumnar epithelium contains the largest stores of glycogen. Ribonucleic acid is most abundant in the mantle-edge gland, and the mucous and mucoprotein cells. Mucopolysaccharides and glycoproteins occur within the mantle-edge epithelium, excepting the mantle-edge gland, and within the shell ground substance. Mucous glands and the sheath surrounding the organic plates are rich in sulfated mucopolysaccharides. Alkaline phosphatase and calcium could not be demonstrated during the prehatching stages. In the adult, alkaline phosphatase reactions are intense along the distal border of the cubocolumnar epithelium, and the basal borders of the epithelia of the mantle-edge gland, median lobe, and ventral lobe. Calcium carbonate occurs as spherules in the connective tissue, in the extrapallial fluid, and within the organic plates and crystalline layers of the shell. In the adult, lipids are most plentiful in the dorsal lobe epithelium and yellow body cells. Vitamin A occurs only within the cubocolumnar and yellow body cells. Cytochrome oxidase is present within the mantle-edge epithelium and, in terms of relative amounts, reflects the activity of the various lobes. Similarly, the size of the Golgi element can be correlated with the activity of the mantle-edge epithelia.

A HISTOLOGICAL STUDY OF THE DEVELOPMENT OF THE MANTLE-EDGE AND SHELL IN THE FRESHWATER GASTROPOD, HELISOMA DURYI EUDISCUS (PILSBRY)

1967 ◽  
Vol 45 (6) ◽  
pp. 1169-1181 ◽  
Author(s):  
S. P. Kapur ◽  
M. A. Gibson
Keyword(s):  
Histological Study ◽  
Ground Substance ◽  
Dorsal Lobe ◽  
Crystalline Layer ◽  
Tissue Core ◽  
Freshwater Gastropod ◽  
Helisoma Duryi ◽  
Yellow Body ◽  
Mantle Edge ◽  
Calcium Crystals

The mantle-edge originates as a peripheral thickening of the evaginated shell gland. During the prehatching stages, it differentiates to form a dorsal lobe including the mantle-edge gland, a median lobe, and a ventral lobe possessing numerous mucous glands. The connective tissue core contains yellow body cells, amoebocytes, and mucoprotein glands. The protoconch is composed of fibers embedded in an amorphous ground substance. Initially it is secreted by the entire mantle-edge but, as development advances, its secretion is progressively limited to the mantle-edge gland. The adult shell is composed of the periostracum, crystalline layer, and an inner layer. The periostracum is a highly tanned layer of fibers embedded in a ground substance. The crystalline layer consists of calcium crystals, the smaller of which contain a nucleus. The inner layer is composed of organic plates which possess amoebocyte nuclei, yellow bodies and calcium granules, and which are surrounded by a thick envelope containing sulfated mucopolysaccharides. These calcium crystals and organic plates are embedded in a ground substance. It is believed that the mantle-edge gland produces the periostracum, that the dorsal lobe contributes to the inner two shell layers, and that the mucous and mucoprotein glands, yellow body cells, and amoebocytes play a significant role in the deposition and calcification of the shell.

Ultrastructural observations on sensory cells and the peripheral nervous system in the mantle edge of Helisoma duryi (Mollusca: Pulmonata)

1978 ◽  
Vol 56 (8) ◽  
pp. 1807-1821 ◽  
Author(s):  
Gwyneth M. Jones ◽  
A. S. M. Saleuddin
Keyword(s):  
Cell Body ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Calcium Deposition ◽  
Sensory Cells ◽  
Dense Granules ◽  
Helisoma Duryi ◽  
Mantle Edge ◽  
Ciliary Tuft ◽  
Intrinsic Neurons

The dorsal surface of the mantle edge produces the overlying periostracum and shell; the ventral epithelium is not involved in shell formation. This regionalization is reflected in the distribution of epithelial receptors. Six ultrastructurally distinct receptor types have been identified on the ventral surface, particularly at the tip of the mantle edge, and one on the dorsal surface. Dorsal receptors occur in a single row along the edge of the mantle edge gland and are also scattered over the dorsal epithelium. Each receptor has a ciliated intraepithelial segment (receptor ending), connected to the subepithelial cell body by a narrow process, and an axon. Variation occurs in the general morphology of the receptor ending, the number of cilia, and the shape of the ciliary tuft. In most types the cell body and axon contain electron-dense granules. Ventral and dorsal receptors differ in the complexity of their subepithelial connections. Ventral receptors send their axons to branches of the pallial nerves. Intrinsic neurons are present in the pallial nerves and in connective tissue and may be responsible for neuromuscular innervation in the mantle edge. Dorsal receptors synapse with intrinsic neurons in a discrete, localised subepithelial plexus. Three types of intrinsic cell have been identified in the plexus, and synapses between them are common. Intrinsic cells form neuromuscular synapses near the plexus and may also innervate epithelial cells in regions responsible for periostracum thickening and calcium deposition.

Calcium storage in the soft tissues of freshwater gastropods. The influence of environmental calcium concentrations

1971 ◽  
Vol 49 (7) ◽  
pp. 1001-1004 ◽  
Author(s):  
G. F. Haley ◽  
M. A. Gibson
Keyword(s):  
Concentration Gradient ◽  
Calcium Concentration ◽  
Soft Tissues ◽  
Preliminary Survey ◽  
Connective Tissues ◽  
Freshwater Gastropods ◽  
Demineralized Water ◽  
Calcium Storage ◽  
Helisoma Duryi ◽  
Mantle Edge

An investigation was made of the influence of an environmental calcium concentration gradient on the storage of calcium spherules in Helisoma duryi eudiscus. A preliminary survey of adult snails revealed that the primary sites of calcium storage are the subepithelial connective tissues of the mantle-edge, pulmonary region, and foot. Snails were hatched and raised for 6 weeks in one of seven solutions of different calcium concentrations. These calcium chloride solutions contained the following concentrations of calcium: 1, 2, 4, 8, 16, 32, and 64 mg calcium/100 ml of demineralized water. It was found that a significantly higher number of calcium spherules are stored at both extremes of this concentration range, that is, in the 1, 32, and 64 mg calcium/100 ml solutions. The effects of the intermediate concentrations on calcium storage are not significantly different with respect to each other.

The opening response of mussels (Mytilus edulis) exposed to rising sea-water concentrations

1981 ◽  
Vol 61 (3) ◽  
pp. 667-678 ◽  
Author(s):  
John Davenport
Keyword(s):  
Mytilus Edulis ◽  
Sea Water ◽  
External Medium ◽  
Mantle Cavity ◽  
Low Salinity ◽  
Medium Exchange ◽  
Mantle Edge

When exposed to water of low salinity specimens of Mytilus edulis L. keep their shell valves tightly closed; they do not gape periodically to test the external medium. Exchange of salts and water between the mantle cavity and the environment is thus minimized. Rising salinities are registered by diffusion of salts to the tentaculate portion of the inhalent siphon and not to any other portion of the mantle edge or to any more deeply located structures.

Development of mantle organs, feeding, and locomotion in postlarval Macoma balthica (L.) (Lamellibranchiata)

1969 ◽  
Vol 47 (4) ◽  
pp. 609-617 ◽  
Author(s):  
J. F. Caddy
Keyword(s):  
Shell Length ◽  
Macoma Balthica ◽  
Adult Form ◽  
Form And Function ◽  
Mantle Edge ◽  
Inhalant Siphon ◽  
And Function ◽  
Development Proceeds

Postlarval M. balthica is well adapted for interstitial life in a particulate sediments, although metamorphosis to the adult form and function is not complete until a shell length of 2 mm is reached.Spatfall at 300–310 μ shell length is followed by a plantigrade stage in which the ciliated plantiform foot is used as an organ of feeding, locomotion, and rejection of pseudofaeces. The inhalant current is produced by the ciliation of the foot and inner demibranch, and enters through the pedal gape. This is already separated from the lumen of the inhalant siphon by the cruciform apparatus. Food sorting in the early postlarvae is exclusively by the palps, which are well developed in the midline to overhang the mouth, and already have simple sorting ridges on their inner surfaces.Siphon development proceeds by infolding of the fusions of the mantle edge around the siphonal apertures. In early postlarvae the pseudofaeces are transported to the pedal gape by the mantle ciliary tract, and swept from the mantle edge by the foot. At approximately 1 mm shell length, rejection of pseudofaeces occurs via the inhalant siphon, which only gradually takes over its adult function as exclusive route of the inhalant current at between 1 and 2 mm.

scholarly journals The marine epilithic diatom Melosira brandinii sp. nov. (Bacillariophyta) from Elephant Island, Antarctic Peninsula, with comments on some related species

2001 ◽  
Vol 49 (1-2) ◽  
pp. 01-12
Author(s):  
Luciano F. Fernandes ◽  
Roseli M. de Souza-Mosimann
Keyword(s):  
New Species ◽  
Antarctic Peninsula ◽  
Related Species ◽  
Barents Sea ◽  
External Surface ◽  
Southern Brazil ◽  
Mantle Edge ◽  
Epilithic Diatom ◽  
A New Species ◽  
Elephant Island

A new species of epilithic diatom is described from samples collected near Elephant Island, Antarctic Peninsula. The cells of Melosira brandinii sp. nov. are joined in filamentous chains and attached by means of long mucilaginous stalks. The valves are circular with the valvar surface composed of irregularly arranged pentagonal Ioculi. Each loculus bears 6-12 pores on the external surface, opening to the innerside through rotae. The corona is only composed of coarse granules. A mantle is well developed, presenting rimoportulae and bearing coarse granules, which are more concentrated at the mantle edge. Comparisons with the related species Melosira arctica, M. moniliformis and M. nummuloides are made. Additionally, photomicrographs of M. arctica from the type material and Barents Sea, and of M. moniliformis from estuaries of Southern Brazil are included.

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