ISSN:
1432-0878
Keywords:
Annulate lamellae
;
Islet organ, bile duct, gut, endothelium
;
Myxine glutinosa
;
Electron microscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Cytoplasmic annulate lamellae were found in the islet organ of a cyclostome, the hagfish (Myxine glutinosa), predominantly in cells interpreted as young proliferating β-cells, and also in endocrine cells and enterocytes of the bile duct and gut and in the endothelial cells of small blood vessels. A close association was observed between annulate lamellae and granular endoplasmic reticulum. Both in cells with and in those without annulate lamellae, crystalline inclusions probably of proteinaceous nature were seen in granular endoplasmic reticulum. These inclusions were occasionally closely associated to annulate lamellae, and a direct continuity could be seen between granular endoplasmic reticulum and the outer nuclear membrane surrounding an inclusion partially situated in the perinuclear cisterna. Rod-shaped structures and rounded electron dense bodies were seen in the nuclei of some islet parenchymal cells. The presence of annulate lamellae in the islet organ and associated tissues of Myxine glutinosa is believed to be related to the very high phylogenetic age of this species. The close association observed between annulate lamellae, granular endoplasmic reticulum, crystalline inclusions, and sometimes also nuclear membranes, may be of functional significance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00219952
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