2 citations found
J Submicrosc Cytol Pathol 23 (3): 419-426 (1991)
Morphogenesis of the secondary envelope of the oocyte in a teleostean
fish of the family Cyprinodontidae: Aphyosemion splendopleure.
Thiaw OT, Mattei X
Departement de Biologie Animale, Faculte des Sciences, Universite Cheikh
Anta Diop de Dakar, Senegal.
The follicular epithelium of the oocyte in Aphyosemion splendopleure is
made up of prismatic cells in which the density of the cytoplasm is variable.
At the end of vitellogenesis the follicular cells show polarity. The rough
endoplasmic reticulum is localized in the cytoplasm situated between the
nucleus and the basal lamina. This reticulum splits up into vesicles limited
by a membrane covered with ribosomes. At the beginning of postvitellogenesis
the Golgi apparatus produces numerous secretion granules in the cytoplasmic
region contiguous to the surface of the oocyte. These Golgi elements, together
with amorphous material whose origin we have not been able to define, form
the secondary envelope of the egg. This envelope is made up of two layers:
an inner layer formed by an agglomeration with a membranous aspect and
a superficial layer made up of tubular elements. The superficial layer
forms an ornamentation clearly shown up by scanning electron microscopy.
Arkh Anat Gistol Embriol 75 (10): 54-62 (1978)
Structure of the follicular epithelium of the gonads Neva lamprey Lampetra
fluviatilis (classification of the follicular epithelia of vertebrates)
Gabaeva NS, Mihailova OP, Markova LG
During its fluvial life, the ovarian follicular epithelium of Lampetra
fluviatilis undergoes polarity formation--in the animal hemisphere the
follicular epithelium is flattened, in the vegetative--it undergoes a secretory
specialization: as the secrete is accumulating, the follicular cells increase
in volume and height, acquiring a cubical form. In connection with monotonous
or differentiating morpho-physiological alterations of follicular epithelium
within a single follicle during the period of rapid oocytic growth, it
is suggested to widen the idea on kinds of its secondary transformation
in the vertebrates. It is suggested to differ: 1) common secondary transformation,
when secondary flattening (for example, in birds) or secondary specialization
(for example, in fish demersal roe) embraces the whole epithelium of the
follicle. In case of common secretory specialization, it can be a) isomorphous--at
identical convertion of the epithelium in the whole follicle (for example,
in sheatfish), b) dimorphous--when there is a certain difference in the
character and degree of secretory specialization of the follicular epithelium
in various follicular areas (for example in Myxine glutinosa); 2) unipolar
secondary transformation when the follicular epithelium undergoes secondary
flattening or secretory specialization only in the area adjacent to one
of the oocyte poles (for example, in Lametra fluviatilis and Blennis follis).
Follicular epithelium of the lamprey testis, unlike in other Anamnia, does
not form spermatocysts; implantation of spermatids and spermia into cytoplasm
of the follicular cells is not observed. Thus, histological structure of
Cyclostomata testis is at a lower stage of development than in other Anamnia.