Electron Microscopy of the Camel Oviductal Epithelium During Early Pregnancy

Author(s):  
Ramesh K. Nayak ◽  
Anwar Zein

The function of the oviduct is essential to the reproductive process of mammals since it allows the meeting of gametes and the beginning of embryonic development. A detailed account on the fine structural changes of the porcine oviductal epithelium during pregnancy has been published. Scanning electron microscopic features of the oviduct from estrus camels have been recently described. To the best of our knowledge, no transmission electron microscopic studies of the camel oviductal epithelium during pregnancy have been reported. The purpose of this study was to identify some of the fine structural changes occurring in the tubal epithelium during early pregnancy and to establish a basis for subsequent physiological and pathological studies.Specimens from the infundibulum region of the oviduct were obtained from 10 pregnant camels. In the present study, it was not possible to determine the exact stage of pregnancy.

Author(s):  
M.G. Hamilton ◽  
T.T. Herskovits ◽  
J.S. Wall

The hemocyanins of molluscs are aggregates of a cylindrical decameric subparticle that assembles into di-, tri-, tetra-, penta-, and larger multi-decameric particles with masses that are multiples of the 4.4 Md decamer. Electron micrographs of these hemocyanins typically show the particles with two profiles: circular representing the cylinder viewed from the end and rectangular representing the side-view of the hollow cylinder.The model proposed by Mellema and Klug from image analysis of a didecameric hemocyanin with the two decamers facing one another with collar (closed) ends outward fits the appearance of side-views of the negatively-stained cylinders. These authors also suggested that there might be caps at the ends. In one of a series of transmission electron microscopic studies of molluscan hemocyanins, Siezen and Van Bruggen supported the Mellema-Klug model, but stated that they had never observed a cap component. With STEM we have tested the end cap hypothesis by direct mass measurements across the end-views of unstained particles.


1979 ◽  
Vol 88 (6_suppl4) ◽  
pp. 2-14 ◽  
Author(s):  
Malcolm D. Graham ◽  
Rodney Perkins

The structure of the normal human stapes was studied with the scanning electron microscope. Specimens were obtained 48 hours after death from adult human temporal bones free from obvious inflammatory disease. The specimens were fixed, dissected, critical-point dried and coated with gold. In this scanning electron microscopic study an attempt has been made to systematically demonstrate the average scanning electron microscopic features of various areas of the normal human stapes. An emphasis has been placed upon demonstrating as clearly as possible the details previously unclear or unrecognized and duplication of many excellent earlier light and electron microscopic studies has not been attempted. The typical appearance of the stapes head, neck, arch, crura and footplate has been presented. It is apparent that there exists a high degree of structural specialization particularly in the stapes arch and footplate area.


1982 ◽  
Vol 14 (3) ◽  
pp. 205-217 ◽  
Author(s):  
Rosmarie Honegger

AbstractOn the basis of light microscopic (LM), scanning electron microscopic (SEM) and transmission electron microscopic (TEM) investigations the Pertusaria-type of ascus is described as a particular functional type. The functionally unitunicate Pertusaria-type is characterized by its structure, staining properties, and by its particular mode of dehiscence. Tripartite ascus walls were observed in LM and TEM. The non-amyloid ascus wall is surrounded by a thin, amyloid outer layer. Both become amorphous at maturity and partly disintegrate. An apically thickened, amyloid inner layer reaches the base of the ascus. In its fine structure this amyloid inner layer resembles the material of the amyloid dome of Lecanora-type asci. It plays an important role during dehiscence and spore discharge. An elongation process was observed prior to dehiscence, at the end of which the ascus tip is situated above the hymenial surface. Dehiscence occurs by bursting or splitting of the whole ascus tip. The Pertusaria-type might represent a side-branch of evolution from bitunicate to unitunicate forms within the Lecanorales.Pertusaria-type asci are restricted to a small number of genera within the Pertusariaceae. A considerable heterogeneity in ascus structure and staining properties was observed within the Pertusariineae sensu Henssen & Jahns (1973) and Henssen (1976).


1978 ◽  
Vol 56 (16) ◽  
pp. 1974-1981 ◽  
Author(s):  
W. H. Miele ◽  
A. E. Linkins

The antheridial strain of the dioecious water mold Achlya bisexualis was grown in chemically defined media using glucose, cellobiose, and selected polysaccharides as carbon sources. Growth and cellulase levels were measured with media containing glucose, cellobiose, and cellulose. Evaluation of cellulase activity in the medium by viscometric and reducing sugar generation assays suggests that cellulase plays a significant role in degrading cellulose for uptake and catabolism by A. bisexualis. Cellulase in glucose-grown cultures exists as a soluble extracellular enzyme complex, while in cellulose-grown cultures much of the enzyme is absorbed to the cellulose. Elution of the cellulose substrate after 96 h growth with NaCl-fortified buffer releases absorbed cellulase in a soluble form. The absorption of cellulase to the substrate and possibly the cell walls of A. bisexualis could account for the rapid loss in dry weight of A. bisexualis during culture on cellulose in a closed system. Scanning electron microscopic (SEM) examination of the walls of A. bisexualis shows disruption in cellulose cultures, which is not evident for glucose-or cellobiose-grown hyphae. Transmission electron microscopic (TEM) photomicrographs show a significant reduction in the wall thickness of cellulose-grown hyphae as compared with glucose-grown samples. This evidence suggests that the enzyme(s) produced during growth on cellulose is (are) capable of binding as an active hydrolase to walls of A. bisexualis or to the cellulosic substrate.


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