Electron Microscope Observations on the Excretory Organ of the Pulmonary Molluscs

Bouillon, Jean; Vandermeerssche, G.

doi:10.1016/b978-1-4832-2795-5.50322-1

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“…The larval kidneys, however, do not contain uric acid. The histochemical tests for urates in Searlesia dim and Nncella canaliculata embryos were negative, and there was no ultrastructural evidence for urates like that seen in terrestrial snails by Bouillon and Vandermeerssche (1962) and Pecheco (1971). The lack of uric acid and the positive PAS staining of the absorptive cells indicates that their large size is due to polysaccharides or polysaccharide-protein complexes and is unlikely due to accumulation of waste products.…”

Section: Lack Of Evidence Of Waste Accumulationmentioning

confidence: 81%

Studies on the Structure and Function of the Larval Kidney Complex of Prosobranch Gastropods

Rivest

1992

The Biological Bulletin

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The larval kidneys of prosobranch gastropods have long been assumed to be involved in handling wastes, but with little supporting evidence. In this study, the larval kidneys of Searlesia dira and Nucella canaliculata were studied with light, electron, and fluorescence microscopy. They consist of three cell types: (1) a large external absorptive cell swollen with heterophagosomes and possessing an endocytotically active external surface; (2) an internal crystal cell with numerous vacuole-bound crystals of a calcium salt and with morphologically complex canaliculi; (3) an internal pore cell characterized by slit-pores that lead to subsurface cisternae, a tubular network, and one or two ciliated ducts that open into the hemocoel. Empirical evidence indicates that the absorptive cell rapidly takes up and stores albumen proteins from the capsular fluid. Absorptive cells were found in 17 of 19 species tested, representing three prosobranch orders, but were not found in 2 opisthobranch or 1 pulmonate species. We hypothesize that the absorptive cells have become specialized for the uptake of capsular albumen prior to the functional differentiation of the gut. However, the nutritional importance of the absorbed albumen proteins and the functions of the crystal and pore cells are presently unknown. No evidence for an excretory function was found for the larval kidney complex; it may be a vestigial protonephridium, the components of which have become disorganized and functionally altered.

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Section: Lack Of Evidence Of Waste Accumulationmentioning

confidence: 81%

Studies on the Structure and Function of the Larval Kidney Complex of Prosobranch Gastropods

Rivest

1992

The Biological Bulletin

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show abstract

Electron Microscope Observations on the Excretory Organ of the Pulmonary Molluscs

Cited by 1 publication

References 1 publication

Studies on the Structure and Function of the Larval Kidney Complex of Prosobranch Gastropods

Studies on the Structure and Function of the Larval Kidney Complex of Prosobranch Gastropods

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