Microanatomy of the bell rim of Aurelia aurita (Cnidaria: Scyphozoa)

1999 ◽  
Vol 77 (1) ◽  
pp. 34-46 ◽  
Author(s):  
David M Chapman
Keyword(s):  
Muscle Fibers ◽  
Aurelia Aurita ◽  
Epithelial Layer ◽  
Mucous Cells ◽  
Deep Side ◽  
Digestive Cells ◽  
Aboral Side ◽  
Thin Part ◽  
Food Groove

The bell rim of Aurelia aurita is described in detail. This medusa has usually eight marginal sensory complexes and many tentacle chambers, the latter made up of a roof, sides (lappets), and a floor. The sole contents of a tentacle chamber are a few bladelike tentacle bases. The distal tentacle is narrow and moniliform and grooved on the adoral side with a folded sheet of muscle fibers on the deep side. Between the underside of the tentacle chamber's floor and a more adoral circumferential flange (pseudovelarium) lies a ciliated food groove lined with a thick amuscular epithelium containing ordinary surface cells, mucous cells, and presumed digestive cells. The subumbrella is bilayered, with an outer epithelial layer that sends thin cytoplasmic sheets to the mesoglea; deeper is a layer of myocytes each with a striated circular myofibril. Towards the periphery, and before the pseudovelarium, is a rim of smooth radial myocytes overlaid with an epithelial layer. The adoral side of the pseudovelarium has smooth radial epitheliomuscular cells. Where the pseudovelarium attaches to the subumbrella, neuromuscular cords traverse the mesoglea to join the adoral side of the tentacles. Along the food groove and midway between rhopalia is a pocket in the pseudovelarium, the food pouch, which collects plankton. The pararhopalial region of the rim is different in that the floor of the tentacle chamber is short or absent; a modified intertentacular partition can sometimes form a protuberance on the aboral side of the pseudovelarium; and the pseudovelarium takes a right-angled turn outwards near the rhopalium to form the thin part of the rhopalial hood. This type of rim is specialized for the concentration and, perhaps, the early digestion of plankton.

Intestinal inflammatory response of powan Coregonus lavaretus (Pisces) to the presence of acanthocephalan infections

Parasitology ◽  
2009 ◽  
Vol 136 (8) ◽  
pp. 929-937 ◽  
Author(s):  
B. S. DEZFULI ◽  
A. LUI ◽  
G. GIOVINAZZO ◽  
P. BOLDRINI ◽  
L. GIARI
Keyword(s):  
Mast Cells ◽  
Inflammatory Response ◽  
Coregonus Lavaretus ◽  
Epithelial Layer ◽  
Mucous Cells ◽  
Intestinal Tissue ◽  
Ultrastructural Studies ◽  
Significant Difference ◽  
Mucosal Folds ◽  
Rodlet Cells

SUMMARYImmunopathological and ultrastructural studies were carried out on the gut of 30 specimens of powan Coregonus lavaretus (L.) from Lake Piediluco, Italy. The digestive tracts of 10 (33·3%) of the powan were found to harbour an acanthocephalan Dentitruncus truttae (Sinzar 1955). The numerous trunk spines of D. truttae reduced the number of mucosal folds near the parasite site of infection. The acanthocephalan induced hyperplasia and hypertrophy of the intestinal mucous cells and many worms were surrounded with an adherent mucous gel. Near the site of acanthocephalan attachment, the number of mucous cells was significantly higher (P<0·01) in comparison to those found in uninfected intestines. Rodlet cells (RCs) were present in the epithelial layer in both infected and uninfected fish, with no significant difference in the numbers observed (P>0·05). In infected intestine, mast cells were more abundant than in uninfected gut (P<0·01). Migration of the mast cells and their intense degranulation at the site of infection were suggested. Immunohistochemical tests applied to sections of intestinal tissue of both infected and uninfected powan revealed that the parasitized C. lavaretus had a larger number of mast cells positive for met-enkephalin and serotonin antisera.

Development of the tentacles and food groove in the jellyfish Aurelia aurita (Cnidaria: Scyphozoa)

2001 ◽  
Vol 79 (4) ◽  
pp. 623-632 ◽  
Author(s):  
David M Chapman
Keyword(s):  
Particulate Matter ◽  
Initial Phase ◽  
Aurelia Aurita ◽  
Lower Side ◽  
Differentiation Zone ◽  
Food Groove ◽  
Bearing Part

The development of the tentacle-bearing part of the rim of the jellyfish Aurelia aurita is described. The newly liberated ephyra lacks appendages at the bell rim between the rhopalial arms (null stage). The next stage (bump stage) has a subumbrellar bump near the rim. The bump then forms a tongue process (tongue stage) on its adoral side. The aboral part of the bump becomes the primordium of the tentacle. The tongue process elongates and spreads circumferentially, finally melding with the lappets of the rhopalial arms. Next the tongue process develops a groove that spreads laterally. The epithelium of the groove becomes glandular and serves as a food groove where particulate matter such as plankton is concentrated and undergoes the initial phase of digestion. The "upper" side of the split tongue process becomes the floor of the tentacle chambers, while the "lower" side becomes the pseudovelarium. The growth and differentiation zone for the medusa's rim is at the junction of the tentaculate part of the rim with the rhopalial region. It is here that tentacle buds form, followed by intertentacular lappets (partitions).

Electron Microscopic Study of the Epithelium of the Seminal Vesicle of Aging Rats

1974 ◽  
Vol 32 ◽  
pp. 138-139
Author(s):  
V. F. Allison ◽  
G. C. Fink ◽  
G. W. Cearley
Keyword(s):  
Cell Growth ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Seminal Vesicle ◽  
Seminal Vesicles ◽  
Epithelial Layer ◽  
Epithelial Hyperplasia ◽  
Electron Microscopic ◽  
Aging Rats ◽  
Pseudostratified Epithelium

It is well known that epithelial hyperplasia (benign hypertrophy) is common in the aging prostate of dogs and man. In contrast, little evidence is available for abnormal epithelial cell growth in seminal vesicles of aging animals. Recently, enlarged seminal vesicles were reported in senescent mice, however, that enlargement resulted from increased storage of secretion in the lumen and occurred concomitant to epithelial hypoplasia in that species.The present study is concerned with electron microscopic observations of changes occurring in the pseudostratified epithelium of the seminal vescles of aging rats. Special attention is given to certain non-epithelial cells which have entered the epithelial layer.

Cytoplasmic Invaginations in Trophoblasts and Epithelial Cells of Rat

1971 ◽  
Vol 29 ◽  
pp. 524-525
Author(s):  
Iracema M. Baccarini
Keyword(s):  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Nuclear Inclusions ◽  
Mucous Cells ◽  
Electron Microscopic ◽  
Cervical Epithelium ◽  
Intact Membrane ◽  
Microscopic Studies ◽  
Abnormal Cells ◽  
Nuclear Features

Some morphological nuclear features (invaginations) in normal and abnormal cells have been described in several electron microscopic studies. They have been referred to by others as blebs, loops, pockets, sheets, bodies, nuclear inclusions and cytoplasmic invaginations. Identical appearing structures were found in cells of the uterine cervical epithelium, in trophoblasts of blastocysts and in trophoblasts of rat placenta.Methods. Uterine cervix (normal rats), rat placenta (9-10 days gestation) and blastocyst were placed in 3% glutarahdehyde for 3 hours. The tissue was washed in phosphate buffer for 24 hours, postfixed in 1%. buffered osmium tetroxide for 1-2 hours and embedded in epon araldite. Sections were double stained with uranyl acetate and lead citrate and viewed in E. M. Siemens 200.Observations. Nuclear invaginations were found in basal, parabasal and mucous cells of the cervix epithelium, in trophoblasts of blastocyst and in trophoblasts of placenta. An oval, round or elongated invagination contained heterogenously cytoplasm surrounded by a double intact membrane; usually several invaginations were found in the same nucleus.

Mitochondrial Changes in Choline-Deficient Rat Myocardium

1968 ◽  
Vol 26 ◽  
pp. 112-113
Author(s):  
F. G. Zaki
Keyword(s):  
Muscle Fibers ◽  
Liver Mitochondria ◽  
Ultrastructural Changes ◽  
Choline Deficiency ◽  
Nutritional Disorder ◽  
Low Protein ◽  
Structural Abnormalities ◽  
Cross Striation ◽  
Pericardial Edema ◽  
Myocardial Lesions

Choline-deficiency was induced in Holtzman young rats of both sexes by feeding them a high fat - low protein diet.Preliminary studies of the ultrastructural changes in the myocardium of these animals have been recently reported from this laboratory. Myocardial lesions first appeared in the form of intraventricular mural thrombi, loss of cross striation of muscle fibers and focal necrosis of muscle cells associated with interstitial myocarditis. Prolonged choline-deficiency induced cardiomegaly associated with pericardial edema.During the early phase of this nutritional disorder, heart mitochondria - despite of not showing any swelling similar to that usually encountered in liver mitochondria of the same animal - ware the most ubiquitous site of marked structural abnormalities. Early changes in mitochondria appeared as vacuolation, disorganization, disruption and loss of cristae. Degenerating mitochondria were often seen quite enlarged and their matrix was replaced by whorls of myelin figures resembling lysosomal structures especially where muscle fibers were undergoing necrosis. In some areas, mitochondria appeared to be unusually clumped together where some contained membranelined vacuoles and others enclosed dense bodies and granular inclusions.

The “KIMWIPE” Effect in Ultra-Thin Cryosections

1985 ◽  
Vol 43 ◽  
pp. 458-459
Author(s):  
I. Taylor ◽  
P. Ingram ◽  
J.R. Sommer
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Ice Crystals ◽  
Crystal Formation ◽  
Ice Crystal ◽  
Thin Sections ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried ◽  
Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

Helicobacter pylori infection produces expression of secretory component in gastric mucous cells

2001 ◽  
Vol 120 (5) ◽  
pp. A708-A709
Author(s):  
T KANEKO ◽  
H OTA ◽  
M HAYAMA ◽  
K NAKAJIMA ◽  
A YOSHIZAWA ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Secretory Component ◽  
Helicobacter Pylori Infection ◽  
Mucous Cells ◽  
Gastric Mucous
Sign in / Sign up

Export Citation Format

Share Document