Ultrastructure of the ovary, ovicapt and oviduct of the spathebothriidean tapeworm Didymobothrium rudolphii (Monticelli, 1890)

2007 ◽  
Vol 52 (2) ◽  
Author(s):  
Larisa Poddubnaya ◽  
David Gibson ◽  
Peter Olson
Keyword(s):  
Comparative Analysis ◽  
Lipid Droplets ◽  
Seminal Receptacle ◽  
Cortical Granules ◽  
Point Of Entry ◽  
Didymobothrium Rudolphii ◽  
Longitudinal Muscles ◽  
Longitudinal Layer

AbstractThe ultrastructural details are presented of the ovary, ovicapt and oviduct of the spathebothriidean tapeworm Didymobothrium rudolphii (Monticelli, 1890) from the intestine of the sand sole Solea lascaris. Oogonia, maturing oocytes and mature oocytes are surrounded by a syncytial interstitial cytoplasm, one of the distinctive traits of which is the presence of numerous myelin-like bodies. Oocyte inclusions comprise cortical granules and a small number of lipid droplets. The thickened, nucleated epithelium of the ovicapt lacks any apical structure and is a prolongation of the narrow ovarian epithelium. The muscular sphincter of the ovicapt is formed by a band of longitudinal muscles and bands of radial muscles at right angles to the longitudinal layer, and numerous myocytes surround the ovicapt wall. The oviduct of D. rudolphii is subdivided into three regions: (1) the proximal oviduct; (2) the fertilization chamber — the region distal to the point of entry of the duct from the seminal receptacle; and (3) the ovovitelline duct — the region distal to the point of entry of the duct from the vitelline reservoir. A comparative analysis is made between the structures of the ovary, ovicapt and oviduct of D. rudolphii and those of two other spathebothriideans, Cyathocephalus truncatus and Diplocotyle olrikii, with a discussion of ultrastructural traits that might be used as taxonomic criteria within the order Spathebothriidea.

267 ULTRASTRUCTURAL CHARACTERISTICS OF NON-MATURED AND IN VITRO MATURED OOCYTES COLLECTED FROM FOLLICULAR, LUTEAL, AND INACTIVE OVARIES OF DOMESTIC CAT (FELIS CATUS) DURING BREEDING AND NON-BREEDING SEASON

2011 ◽  
Vol 23 (1) ◽  
pp. 231
Author(s):  
L. R. Martins ◽  
C. B. Fernades ◽  
B. W. Minto ◽  
F. C. Landim-Alvarenga ◽  
M. D. Lopes
Keyword(s):  
Breeding Season ◽  
Central Region ◽  
Lipid Droplets ◽  
Domestic Cat ◽  
Perivitelline Space ◽  
Cortical Granules ◽  
Electronic Microscopy ◽  
Transmission Electronic Microscopy ◽  
Ultrastructural Characteristics

The aim of this experiment was to describe the ultrastructural characteristics of non-matured (NM) and in vitro matured (IVM) cumulus–oophorus complexes (COC) recovered from adult queens during the breeding season (BS; July, August, and September) and the non-breeding season (NBS; January, February, and March) in southeast Brazil. Transmission electronic microscopy was performed in NM COC immediately after harvest, and IVM COC were matured for 36 h before transmission electronic microscopy. All IVM COC during both seasons were at metaphase II stage. Specimens were divided into COC from inactive ovaries, follicular ovaries, and luteal ovaries recovered during BS and NBS. During NBS, NM follicular and inactive COC presented a narrow perivitelline space covered with microvilli, which were less evident in NM luteal COC. Cumulus-cell projections penetrated the zona pellucida forming gap junctions with the oolemma in all NM COC. In the cytoplasm of NM inactive COC, lipid droplets and vesicles were evenly distributed in the ooplasm except for in the cortical zone, where clusters of mitochondria were observed. Non-matured luteal COC were also characterised by peripheral mitochondrial clusters, but greater clusters could also be seen centrally in the cytoplasm. In contrast, NM follicular COC were characterised by evenly distributed mitochondria within the ooplasma. In NM inactive and follicular COC, cortical granules were seen only in the central region of the cytoplasm, but the electron density of these organelles appeared to be low and Golgi complexes were often seen in association with these granules. The density of cortical granules in NM follicular COC was higher, but they were also present in central regions of the ooplasm. In all NM COC, a well-developed Golgi complex was observed. In all IVM COC, mitochondria clusters were no longer observed, and these organelles presented an even distribution toward the ooplasm. High-density cortical granules were present in the peripheral region of all IVM COC, although a small number could still be observed in central region of the ooplasm of IVM follicular COC. The perivitelline space was more prominent in IVM COC. During BS, COC characteristics were similar to NM COC during NBS; the presence of mitochondrial clusters associated with lipid droplets, well-developed cortical granules, and the presence of nuage could be observed, except that all cortical granules located in the central region of the cytoplasm of NM follicular COC during BS. A great amount of smooth endoplasmic reticulum could be verified in NM follicular and luteal COC. During BS, all IVM COC presented uniform distribution of mitochondria and peripheral distribution of cortical granules in the ooplasma. These results indicate that IVM was efficient in inducing the morphological changes necessary for cytoplasmic maturation of cat COC, independently of the ovarian status. The authors acknowledge FAPESP.

Ultrastructure and mitochondrial numbers in pre- and postpubertal pig oocytes

2016 ◽  
Vol 28 (5) ◽  
pp. 586 ◽  
Author(s):  
Hanne Skovsgaard Pedersen ◽  
Henrik Callesen ◽  
Peter Løvendahl ◽  
Fenghua Chen ◽  
Jens Randel Nyengaard ◽  
...  
Keyword(s):  
Lipid Droplets ◽  
Close Contact ◽  
Cumulus Cells ◽  
Cell Types ◽  
Developmental Competence ◽  
Numerical Density ◽  
Cortical Granules ◽  
Oocyte Competence ◽  
Mitochondrial Number ◽  
Different Diameters

Prepubertal pig oocytes are associated with lower developmental competence. The aim of this experiment was to conduct an exhaustive survey of oocyte ultrastructure and to use a design-unbiased stereological approach to quantify the numerical density and total number of mitochondria in oocytes with different diameters from pre- and postpubertal pigs. The ultrastructure of smaller prepubertal immature oocytes indicated active cells in close contact with cumulus cells. The postpubertal oocytes were more quiescent cell types. The small prepubertal oocytes had a lower total mitochondrial number, but no differences were observed in mitochondrial densities between groups. Mature postpubertal oocytes adhered to the following characteristics: presence of metaphase II, lack of contact between cumulus cells and oocyte, absence of rough endoplasmic reticulum and Golgi complexes, peripheral location of cortical granules and central localisation of mitochondria, vesicles and lipid droplets. Prepubertal oocytes displayed more variation. The ultrastructure of large pre- and postpubertal oocytes was compatible with higher developmental competence, whereas that of smaller prepubertal oocytes could explain their reduced capacity. The higher number of mitochondria in large pre- and postpubertal oocytes could have an influence on oocyte competence, by increasing the pool of mitochondria available for early embryonic development.

Vitellocyte ultrastructure in the cestode Didymobothrium rudolphii (Monticelli, 1890): possible evidence for the recognition of divergent taxa within the Spathebothriidea

2006 ◽  
Vol 51 (4) ◽  
Author(s):  
Larisa Poddubnaya ◽  
David Gibson ◽  
Zdzisław Świderski ◽  
Peter Olson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lipid Droplets ◽  
Interstitial Tissue ◽  
Morphological Parameters ◽  
Transmission Electron ◽  
Shell Globule ◽  
Didymobothrium Rudolphii ◽  
First Time ◽  
Electron Lucent

AbstractIn the spathebothriidean tapeworm Didymobothrium rudolphii (Monticelli, 1890) the fine structure of the vitellocytes at different stages of their development within the vitelline follicles, vitelline ducts and uterus was studied for the first time using transmission electron microscopy. The vitellocyte inclusions of D. rudolphii are shell globule clusters containing tightly packed shell globules associated with a matrix of moderate electron density, glycogen granules, large electron-lucent lipid droplets (up to 3 μm in diameter), and, occasionally, a lipid droplet may occur in the nucleus of the vitellocytes. The diameter of the clusters ranges from 0.4 to 2.5 μm, the number of shell globules in the clusters varies from 8 to 45, and the size of the globules ranges from 0.12 to 0.25 μm and they are of approximately homogeneous sizes within a cluster. Most vitellocyte lipid droplets have a heterogeneous configuration with a ‘cavity’ inside them when they are within vitelline ducts and intrauterine eggs. Vitellocytes of the eggs contain dark concentric bodies and lipid droplets. The interstitial tissue has a syncytial structure. The morphological parameters of the diameter and shape of shell globule clusters, arrangement of shell globules in clusters, number and diameter of globules within clusters, types of lipid droplets and presence of dark concentric bodies are compared with those of two other spathebothriidean genera, Cyathocephalus and Diplocotyle. The comparative data demonstrate that vitelline material morphology has unique features in three spathenothriidean genera and may be used as evidence for the recognition of separate taxa.

Interaction of two electrical pacemakers in muscularis of canine proximal colon

1987 ◽  
Vol 252 (3) ◽  
pp. C290-C299 ◽  
Author(s):  
T. K. Smith ◽  
J. B. Reed ◽  
K. M. Sanders
Keyword(s):  
Action Potentials ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Proximal Colon ◽  
Slow Waves ◽  
Cross Sectional ◽  
Electrical Oscillation ◽  
Discrete Populations ◽  
Longitudinal Muscles ◽  
Longitudinal Layer

Experiments were performed to determine the source of the 20 cycles/min electrical oscillation commonly seen in colonic electrical records, the influence of the 20 cycles/min rhythm on the circular and longitudinal muscle layers, and the interactions between the 20 cycles/min rhythm and slow waves in circular muscle cells. Cross-sectional muscle preparations of the canine proximal colon were used to allow impalement of cells at any point through the thickness of the muscularis. Intracellular recordings from circular muscle cells clearly showed the two characteristic pacemaker frequencies in the colon (6 cycles/min slow waves; 20 cycles/min oscillations). The 20 cycles/min oscillations were recorded from longitudinal and circular muscle cells. Their amplitudes were greatest at the myenteric border. In the longitudinal layer the 20 cycles/min events initiated action potentials; in circular muscle the 20 cycles/min events summed with slow waves. Simultaneous recordings from circular and longitudinal cells across the myenteric border demonstrated that events in the two layers were usually in phase, suggesting that the two layers are electrically coupled and are paced by a common pacemaker. The amplitude of the 20 cycles/min events decayed with distance from the myenteric border in both circular and longitudinal muscles. The data demonstrate that two discrete populations of pacemaker cells generate the spontaneous electrical activity in the colon. Both events appear to passively spread through the circular muscle. It is the summation of these events that appears to serve as the signal for excitation-contraction coupling in circular muscle.

scholarly journals A CYTOLOGICAL STUDY OF THE CENTRIFUGED WHOLE, HALF, AND QUARTER EGGS OF THE SEA URCHIN ARBACIA PUNCTULATA

1970 ◽  
Vol 47 (3) ◽  
pp. 711-733 ◽  
Author(s):  
Everett Anderson
Keyword(s):  
Lipid Droplets ◽  
Sea Water ◽  
Cytological Study ◽  
Germinal Vesicle ◽  
The Other ◽  
Annulate Lamellae ◽  
Cortical Granules ◽  
Clear Zone ◽  
Arbacia Punctulata ◽  
Peripheral Position

While the ooplasmic components of centrifuged eggs of Arbacia punctulata do not stratify in homogeneous layers, we have obtained the following strata beginning with the centripetal end: lipid droplets, pronucleus, clear zone, mitochondria, yolk, and pigment. Whereas mitochondria may be found mingled with yolk bodies, we have never observed lipid droplets nor pigment bodies among any of the other inclusions. The so-called clear zone contains a heterogeneous population of inclusions: annulate lamellae, heavy bodies, Golgi complexes, and rod-containing vacuoles. The peripheral cortical granules of immature (germinal vesicle stage) and of mature eggs are not dislodged from the cortical ooplasm with the centrifugal force utilized. When the eggs are treated with urethane, prior to centrifugation, the cortical granules of mature eggs abandon their peripheral position. Further centrifugation of the initially stratified eggs produces nucleated and nonnucleated halves and the centrifugation of the halves results in quarters. The cytology of the halves and quarters is discussed. The halves and quarters have been activated with either sperm or hypertonic sea water. With the exception of the nucleated halves, we were unable to obtain plutei larvae from the other fractions (red halves and quarters). We believe that the lack of development of the various fragments is a function of the balance of particular inclusions necessary for differentiation.

Ultrastructural Cytopiasmic Changes of Adrenal Cortex During Pregnancy

1969 ◽  
Vol 27 ◽  
pp. 298-299
Author(s):  
T. M. Murad ◽  
Karen Israel ◽  
Jack C. Geer
Keyword(s):  
Adrenal Gland ◽  
Steroid Hormones ◽  
Adrenal Cortex ◽  
Lipid Droplets ◽  
Plasma Cholesterol ◽  
Adrenal Steroids ◽  
Dynamic Changes ◽  
Cortical Cells ◽  
Acetyl Coenzyme A ◽  
Adrenal Cortical Cells

Adrenal steroids are normally synthesized from acetyl coenzyme A via cholesterol. Cholesterol is also shown to enter the adrenal gland and to be localized in the lipid droplets of the adrenal cortical cells. Both pregnenolone and progesterone act as intermediates in the conversion of cholesterol into steroid hormones. During pregnancy an increased level of plasma cholesterol is known to be associated with an increase of the adrenal corticoid and progesterone. The present study is designed to demonstrate whether the adrenal cortical cells show any dynamic changes during pregnancy.

Morphometric SEM study of the effects of ACTH on endothelial fenestrae in the rat adrenal cortex

1984 ◽  
Vol 42 ◽  
pp. 234-235
Author(s):  
J. Curtis ◽  
K. S. Schwartz ◽  
R. P. Apkarian
Keyword(s):  
Anterior Pituitary ◽  
Lipid Droplets ◽  
Adrenocorticotropic Hormone ◽  
Unit Area ◽  
High Density Lipoproteins ◽  
Capillary Endothelium ◽  
Zona Fasciculata ◽  
Sem Study ◽  
Saline Vehicle ◽  
Scanning Electron

A scanning electron microscope (SEM) study was made of the effect of adrenocorticotropic hormone (ACTH) on the size and numbers of fenestrae/unit area in the capillary endothelium of the zona fasciculata (ZF) of the rat adrenal. The stimulatory effect of ACTH on cholesterol uptake via high density lipoproteins in the rat and evidence for the secretion of glucocorticoids by exocytosis of lipid droplets described by Rhodin suggest that endothelial change may accompany these transport phenomena.Twelve rats received two Dexamethasone (DEX) ip injections (25 μg DEX/100 g body wt.), the first at 8 PM and the second at 8 AM the next day, to inhibit the release of endogenous ACTH by the anterior pituitary. The animals were then divided into two groups. Six animals received only saline vehicle and six rats received ACTH (100 ng/100 g body wt.).

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