The postnatal maturation of efferent tubules in the rat: a light and electron microscopy study

Development ◽  
1986 ◽  
Vol 96 (1) ◽  
pp. 51-63
Author(s):  
Sandro Francavilla ◽  
Sergio Moscardelli ◽  
Bernardino Bruno ◽  
Patrizio Scorza Barcellona ◽  
Cesare De Martino
Keyword(s):  
Electron Microscopy ◽  
Fluid Transport ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Seminiferous Tubules ◽  
Genital Duct ◽  
Postnatal Maturation ◽  
Postnatal Differentiation ◽  
Tubule Wall

The postnatal maturation of the epithelium and tubule wall of efferent tubules in the rat was investigated by light and transmission electron microscopy, from birth to 50 days of age, when sperms were released from the seminiferous tubules and appeared in the genital duct. At the end of the first week of life, an endocytotic apparatus is differentiated in the epithelial cells. During the third week of life, efferent tubules developed specializations for the transport of sperms and fluids, namely the appearance of ciliated elements interspersed among the principal cells of the epithelium, and differentiation of myoid elements in the tubule wall. The appearance of specializations related to endocytosis and fluid transport across the epithelium preceded the canalization of the seminiferous cords which, in fact, is reported to appear at the end of the second week of life in the rat, along with the initial secretion of testicular fluid. This suggested that the maturation of efferent tubules is not triggered by the passage of testicular fluid, as surmised for the postnatal differentiation of caput epididymis. The postnatal maturation of efferent tubules was almost complete 35 days after birth. The appearance of sperms in the genital duct of 50-day-old animals was not associated with any remarkable structural change.

scholarly journals Light and electron microscopy study of late embryonic development in the land snail Limicolaria flammea (Müller) (Pulmonata, Achatinidae)

2007 ◽  
Vol 24 (2) ◽  
pp. 436-441 ◽  
Author(s):  
Rosemary I. Egonmwan
Keyword(s):  
Electron Microscopy ◽  
Embryonic Development ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Land Snail ◽  
Electron Microscopy Study ◽  
Advanced Embryo ◽  
Embryonic Shell ◽  
Advanced Stages ◽  
Late Stages

The late stages of embryogenesis in the achatinid land snail Limicolariaflammea (Müller, 1774) were described using light and electron microscopy. Embryos at various stages of development were present in the eggs during the first hour after they were laid, from 4-cell blastulae to morulae and fairly advanced stages. The advanced embryo which was fully developed on the second day bears a long cephalic sac, first to be developed, attached to the embryo and a podocyst which is attached to the foot of the embryo. Both of these structures are reduced in size as embryogenesis progresses until they finally disappear at about the 7th day after the egg was deposited. The embryonic shell was apparent on the second day and spiral coiling was apparent at about day 5. The spiral shell had one whorl when formed and more spirals were added so that at hatching the young snails had three whorls.

Meningiomas. A Light and Electron Microscopy Study

1981 ◽  
pp. 122-125 ◽  
Author(s):  
Filomeno Tedeschi ◽  
R. Brizzi ◽  
A. Lechi ◽  
G. Trabattoni ◽  
C. Ferrari ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study

Fine structure of Metchnikovella incurvata Caullery and Mesnil 1914 (microsporidia), a hyperparasite of gregarines Polyrhabdina sp. from the polychaete Pygospio elegans

Parasitology ◽  
2013 ◽  
Vol 140 (7) ◽  
pp. 855-867 ◽  
Author(s):  
Y. Y. SOKOLOVA ◽  
G. G. PASKEROVA ◽  
Y. M. ROTARI ◽  
E. S. NASSONOVA ◽  
A. V. SMIRNOV
Keyword(s):  
Electron Microscopy ◽  
Marine Invertebrates ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Life Cycles ◽  
Single Family ◽  
Host Cytoplasm ◽  
History Of ◽  
Multinuclear Cells

SUMMARYClass Rudimicrosporea Sprague 1977, with its single family Metchnikovellidae, comprises hyperparasites of gregarines from the guts of marine invertebrates. Metchnikovellids remain poorly studied in spite of their significance to the evolutionary history of microsporidia; their ultrastructure and life cycles require further investigation. Here we present results of the light- and electron-microscopy study of Metchnikovella incurvata Caulleri and Mesnil 1914, isolated from lecudinid gregarines, parasitizing polychaetes Pygospio elegans in the White Sea littoral zone, and yet described only on the light-microscopic level. The life cycle of this microsporidium includes 2 sporogonies: free (FS) and sac-bound (SBS). In FS, sporonts develop into multinuclear cells (sporogonial plasmodia), which generate sporoblasts and free spores residing in direct contact with the host cytoplasm. Electron microscopy revealed their metchnikovellidean structure: a horseshoe-shaped nucleus, short manubrium perpendicular to the long axis of the spore, and a polar cap in a separate membrane container. Merogony was not observed. The earliest stages of SBS were chains of binucleate cells. They underwent a series of nuclear and cell divisions, produced extracellular envelopes, and split into boomerang-shaped spore sacs, containing up to 16 spores each. Ultrastructure and sizes of sac-bounded spores were similar to those of free-living ones. An amended diagnosis of M. incurvata is provided.

Naegleria fowleri: Light and electron microscopy study of mitosis

2009 ◽  
Vol 122 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Arturo González-Robles ◽  
Ana Ruth Cristóbal-Ramos ◽  
Mónica González-Lázaro ◽  
Maritza Omaña-Molina ◽  
Adolfo Martínez-Palomo
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Naegleria Fowleri ◽  
Nægleria Fowleri
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