Ultrastructure of the digestive system and experimental study of feeding in the monogenean skin and fin parasite Macrogyrodactylus congolensis

2013 ◽  
Vol 58 (4) ◽  
Author(s):  
Safaa Arafa ◽  
Mohammed El-Naggar ◽  
Graham Kearn
Keyword(s):  
Electron Microscopy ◽  
Lipid Droplets ◽  
Digestive System ◽  
Intestinal Lumen ◽  
Luminal Surface ◽  
Brown Colour ◽  
Transmission Electron ◽  
Large Particles ◽  
H 30 ◽  
Macrogyrodactylus Congolensis

AbstractIn the present study, transmission electron microscopy (TEM) has been used to study the ultrastructure of the digestive system, namely the pharynx, oesophageal glands and intestine, of the monogenean skin and fin parasite Macrogyrodactylus congolensis. The pharynx consists of an anterior highly muscular region and a posterior mainly glandular syncytial region. The anterior region is provided with six pharyngeal papillae, the centre of each of which is occupied by electron dense secretory bodies, identical with those in the posterior region of the pharynx. The intestine has an uninterrupted syncytial gastrodermis and the luminal surface is provided with many unbranched lamellae. The intestine of living specimens contains large and small granules which give it a reddish brown colour. Large particles, presumed to be lipid droplets, and small granules, presumed to be melanin granules, were found in the gastrodermis and in the intestinal lumen. Parasites were induced to feed and then preserved for TEM at the following intervals: just after feeding, 30 min after feeding, 1 h 30 min after feeding and 2 h after feeding. The specimens were then processed for TEM and sections cut through the intestine of each specimen were examined with the transmission electron microscope. Three types of vacuoles (V1, V2, V3) were detected in the gastrodermis. Vacuoles V1 have thick walls and are likely to be endocytotic, enclosing luminal contents at the surface of the gastrodermis. V2 vacuoles may be lysosomes that fuse with V1 vacuoles. V3 vacuoles may serve to dispose of residual digestive material into the lumen.

Ultrastructural Study of Rat Colon Following Psyllium Ingestion

1985 ◽  
Vol 43 ◽  
pp. 580-581
Author(s):  
F.G. Lightfoot ◽  
L.E. Grau ◽  
M.M. Cassidy ◽  
G.R. Tadvalkar ◽  
G.V. Vahouny
Keyword(s):  
Electron Microscopy ◽  
Morphological Changes ◽  
Large Population ◽  
Rat Colon ◽  
Gastrointestinal Disorders ◽  
Luminal Surface ◽  
Fecal Material ◽  
Transmission Electron ◽  
Morphologic Analysis ◽  
Irritable Bowel

Psyllium hydrophillic mucilloid is a natural gelling fiber consumed by a large population of our society. It is used as a bulk-producing laxative and in the treatment of gastrointestinal disorders such as “Irritable Bowel Syndrome”. The literature pertaining to the ultrastructural effects of this agent is sparse.This study documents morphological changes induced by psyllium. Animals fed a diet containing 2% psyllium for four weeks were subsequently sacrificed and processed for scanning and transmission electron microscopy. The colon contained fecal material combined with psyllium which conformed to the contour of the luminal surface. This mixture formed surface replicas of the intestinal mucosa. These replicas and their related colonic sites were processed for morphologic analysis.

Nectary ultrastructure and secretory modes in three species of Tillandsia (Bromeliaceae) that have different pollinators

Botany ◽  
2013 ◽  
Vol 91 (11) ◽  
pp. 786-798 ◽  
Author(s):  
Stefano Mosti ◽  
Cynthia Ross Friedman ◽  
Ettore Pacini ◽  
Luigi Brighigna ◽  
Alessio Papini
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Lipid Droplets ◽  
Protein Crystals ◽  
Transmission Electron ◽  
Floral Nectaries ◽  
Secretion Product ◽  
Pollination Mode ◽  
Cell Wall Ingrowths ◽  
Holocrine Secretion

The floral nectaries of three Tillandsia L. spp. having different pollinators were investigated with transmission electron microscopy (TEM) to describe the previously unstudied ultrastructure of the nectar-producing tissues (primarily the epidermis) and also to determine if any differences in the ultrastructural features could be correlated to pollination mode. We determined that there were variations in nectaries among the three species, and that these may be linked to pollinator choice. Tillandsia seleriana Mez, which has a strict relationship with ants, had a nectary epithelium characterized by abundant dictyosomes and endoplasmic reticulum (ER), and a final degeneration stage possibly leading to holocrine secretion. The presence of protein crystals in epithelial plastids was correlated to a nectar enriched with amino acids and proteins, likely functioning to provide a protein-enriched diet and possibly defence against pathogens. Epithelial cells of the hummingbird-pollinated Tillandsia juncea (Ruiz et Pav.) Poir. nectary displayed cell wall ingrowths and dictyosomes and also contained cytoplasmic lipid droplets and protein crystals within plastids, both of which would enrich the nectar for hummingbirds. The nectary epithelium and the parenchyma of bat-pollinated Tillandsia grandis Schltdl. possessed a few cubic protein crystals in the plastids and its secretion product appeared electron transparent.

Light and transmission electron microscopy of English oak ectomycorrhizal short roots

1984 ◽  
Vol 62 (7) ◽  
pp. 1327-1335 ◽  
Author(s):  
H. H. Edwards ◽  
R. V. Gessner
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Quercus Robur ◽  
Lipid Droplets ◽  
Apical Meristem ◽  
Fungal Symbiont ◽  
Host Root ◽  
Transmission Electron ◽  
Cell Layers ◽  
English Oak

The incorporation of caffeine in standard transmission electron microscope fixation procedures has allowed good preservation and embedment of ectomycorrhizal short roots of English oak (Quercus robur L.). In the mantle the most conspicuous structures are cystidia which radiate outwards from the surface. These conically shaped cells have knobs at their tips and thickened cell walls. The cystidia and other outer mantle cells contain many cytoplasmic constituents, whereas the inner mantle cells are nearly devoid of cytoplasm. The mantle cells are held together by an intercellular slime network. The Hartig net cells are filled with cytoplasm and contain numerous lipid droplets. Typical dolipore septa separate the cells; however, these cells have irregularly branched shapes. The host root tissue appears little altered by the presence of the fungal symbiont. However, the root cap consists of only a few cell layers. The apical meristem is functional as evidenced by the presence of newly divided cells and microtubules lining enlarging cells.

scholarly journals Comparative structure of the osmophores in the flowers of Stanhopea graveolens Lindley and Cycnoches chlorochilon Klotzsch (Orchidaceae)

2012 ◽  
Vol 65 (2) ◽  
pp. 11-22 ◽  
Author(s):  
Sebastian Antoń ◽  
Magdalena Kamińska ◽  
Małgorzata Stpiczyńska
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Lipid Droplets ◽  
Secretory Cells ◽  
Vascular Bundles ◽  
Scent Glands ◽  
Euglossine Bees ◽  
Dense Cytoplasm ◽  
Transmission Electron ◽  
Comparative Structure

The structure of the osmophores in <i>Stanhopea graveolens</i> and <i>Cycnoches chlorochilon</i> was studied by means of light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The scent glands are located in the basal part of the labellum. The surface of the osmophores is wrinkled or rugose, which increases the area of fragrance emission. On the surface of the epidermis, remnants of secretion are noticeable in <i>S. graveolens</i>, but these are absent in <i>C. chlorochilon</i>. The osmophore tissue is composed of secretory epidermal cells and several layers of subepidermal parenchyma, and it is supplied by vascular bundles that run in ground parenchyma. The secretory cells have large nuclei, a dense cytoplasm with numerous ER profiles, lipid droplets, and plastids with a substantial amount of starch, which are probably involved in the synthesis of volatile substances. In the cell walls of the osmophore cells, numerous pits with plasmodesmata occur that are likely to take part in symplastic transport of the scent compounds. The structure of the osmophores is similar in both investigated species. Both <i>S. graveolens</i> and <i>C. chlorochilon</i> are pollinated by euglossine bees, and such similarity results from adaptation to effective scent emission and attraction of pollinators.

Macromolecular crystal data phased by negative-stained electron-microscopy reconstructions

2010 ◽  
Vol 66 (5) ◽  
pp. 514-521 ◽  
Author(s):  
Stefano Trapani ◽  
Guy Schoehn ◽  
Jorge Navaza ◽  
Chantal Abergel
Keyword(s):  
Electron Microscopy ◽  
Streptomyces Coelicolor ◽  
Medium Size ◽  
Molecular Replacement ◽  
X Ray Diffraction ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
Large Particles ◽  
One Step ◽  
Type Ii Dehydroquinase

The combination of transmission electron microscopy with X-ray diffraction data is usually limited to relatively large particles. Here, the approach is continued one step further by utilizing negative staining, a technique that is of wider applicability than cryo-electron microscopy, to produce models of medium-size proteins suitable for molecular replacement. The technique was used to solve the crystal structure of the dodecameric type II dehydroquinase enzyme fromCandida albicans(∼190 kDa) and that of the orthologousStreptomyces coelicolorprotein.

scholarly journals Behavior of plasminogen at the luminal surface of the normal and deendothelialized rabbit aorta in vivo and in vitro

Blood ◽  
1988 ◽  
Vol 71 (5) ◽  
pp. 1260-1267 ◽  
Author(s):  
MW Hatton ◽  
SL Moar ◽  
M Richardson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Luminal Surface ◽  
Plasmin Activity ◽  
Transmission Electron ◽  
Rapid Adsorption

Abstract The behavior of purified rabbit plasminogen at the luminal surface of the uninjured and deendothelialized rabbit aorta has been studied in vivo and in vitro. After intravenous injection, 125I-plasminogen associated rapidly with the endothelium (approximately 0.1 pmol/cm2 at saturation) and passed through to accumulate in the subendothelium. At two to 15 hours after injection, 11 to 15 times more radioactivity was associated with the subendothelium than with the endothelium. Removal of the endothelium by balloon catheter led to a rapid adsorption of 125I-plasminogen by the luminal surface of the vessel; saturation (9.1 pmol/cm2) was attained at ten to 20 minutes after deendothelialization. Of the adsorbed plasminogen (radioactivity), only 2% to 4% was associated with the adherent platelet monolayer. Uptake of 125I- plasminogen by the deendothelialized vessel was not significantly inhibited by epsilon-aminohexanoic acid whether injected before or after the 125I-plasminogen. No evidence of plasmin activity at the aorta surface was found from either transmission electron microscopy studies or from amidolytic assays of plasminogen-saturated deendothelialized aorta samples before or after urokinase treatment. Balloon catheter treatment in vivo, however, generated significant antiplasmin activity of the deendothelialized aorta surface. We conclude that plasmin formed in vivo is probably inactivated by the antiplasmin activity that is associated with the subendothelium.

Microstructures of Amorphic Diamond™ Films Deposited by Laser-Ablation

1995 ◽  
Vol 416 ◽  
Author(s):  
Hyunchul Sohn ◽  
Kannan Krishnan ◽  
Richard Fink
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Laser Ablation ◽  
Energy Loss ◽  
Annealing Temperature ◽  
Laser Ablation Method ◽  
Transmission Electron ◽  
Large Particles ◽  
Particulate Size ◽  
Electron Energy Loss

ABSTRACTMicrostructures of Amorphic Diamond™ films deposited by laser ablation method were investigated using transmission electron microscopy. The AD films matrix was homogeneous with a sp3-type bonding fraction of 40%∼45% confirmed by electron energy-loss spectroscopy. The sp3 bonding fraction decreased monotonically with increasing annealing temperature. The main inhomogeneity in Amorphic Diamond™ was observed to be particulates of high density (>105/cm2) distributed through the depth of the film. Particulate size ranged from ∼10nm to a few μm and most of them were identified to be graphite. Large particles (>0.5μm) were agglomerates of smaller graphite crystallites. Possible mechanisms for cold field emission are discussed based on the microstructures observed in these AD films.

Ultrastructure of the digestive system of adult Sanguinicola inermis

1994 ◽  
Vol 68 (2) ◽  
pp. 149-154 ◽  
Author(s):  
D.F. McMichael-Phillips ◽  
J.W. Lewis ◽  
M.C. Thorndyke
Keyword(s):  
Digestive System ◽  
Alimentary Tract ◽  
Secretory Granules ◽  
Single Layer ◽  
Host Cells ◽  
Intestinal Lumen ◽  
Intestinal Cells ◽  
Apical Surface ◽  
Apical Cytoplasm ◽  
Transmission Electron

AbstractThe alimentary tract of adult Sanguinicola inermis Plehn, 1905 (Digenea: Sanguinicolidae) was studied by transmission electron microscopy. A highly developed muscular region, likely to be a modified sucker, is present anteriorly to the oesophagus. The tegumental oesophagus, on the basis of the characteristics of the surface cytoplasm, is differentiated into anterior, median and posterior regions with the apical cytoplasm of the median oesophagus drawn into extracellular vesicles from which arise surface knobs. The oesophagus leads to a cellular intestine composed of a single layer of epithelial cells. The apical surface of the intestine is drawn into short luminal projections and the intestinal cells contain numerous organelles and secretory granules. No host cells or cell debris were evident within the alimentary tract, although the intestinal lumen was filled with electron-dense material.

Ultrastructural diagnosis of renal oncocytoma

1992 ◽  
Vol 50 (1) ◽  
pp. 626-627
Author(s):  
Shirley Siew ◽  
Mehboob Fatteh
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Blood Vessels ◽  
Renal Tumors ◽  
Renal Oncocytoma ◽  
Luminal Surface ◽  
Transmission Electron ◽  
Granular Cytoplasm ◽  
Retrograde Pyelogram ◽  
Thin Walled

Renal oncocytoma is a comparatively rare tumor, having an incidence 1/20th that of renal cell carcinoma, from which it has to be differentiated. We report a case of a 61 year old man who was found to have albuminuria 100 mg/dL on a routine physical examination. A retrograde pyelogram showed splaying of the right upper pole infundibula. Two right renal tumors were shown on renal CT scan and there were multiple hypervascular masses on angiography. A right radical nephrectomy was performed. The kidney weighed 176 grains and measured 11 × 7.5 × 5 cm. There were several dark brown nodules in the upper pole, lower pole and midportion of the kidney. Some of the nodules protruded onto the cortical surface, stretching the overlying capsule, but, there was no evidence of capsular nor renal vein invasion. The largest nodule measured 4.5 × 4 × 4 cm. Histologic examination showed a distinct line of demarcation between the tumors and the normal kidney. Occasional thickened vessels were noted at the border. For the greater part, the tumor showed a tubular or acinar architecture, although the lumina of some of the tubules were narrow. The tubules were lined by large, polygonal eosinophilic cells with a granular cytoplasm. There was no evidence of nuclear atypicality nor mitotic activity. Thin walled blood vessels were present between the tubules. Transmission electron microscopy showed the presence of irregular tubules, surrounded by a well formed basement membrane. The tubules were separated by thin walled blood vessels (Fig. 1). The luminal surface of the cells lacked microvilli – Nuclei were comparatively small and irregular in shape. Lysosomes were concentrated towards the luminal surface. There were occasional lipid vacuoles. The cytoplasm contained large numbers of mitochondria with membranous cristae (Fig. 2) . These ultrastructural characteristics are in keeping with those of a renal oncocytoma. Comment: The term oncocyte1 is applied, at the light microscopic level, to large epithelial cells, which have a markedly eosinophilic and granular cytoplasm. Transmission electron microscopy shows the presence of an abundance of mitochondria filling the cytoplasm. Oncocytomas are tumors composed of a uniform population of such cells. Renal oncocytoma is considered to be a benign cortical adenoma. It has been postulated that it arises from proximal tubular epithelium. Features that distinguish renal oncocytoma from other adenomas are that they may reach a large size (7cm) and that they maybe multicentric in the same kidney (reported in 5% of cases). The dark brown bulging nodules present in our case are typical of the gross appearance of renal oncocytoma. Various theories have been proposed to account for the marked increase of mitochondria, including that it is due to a neoplastic proliferation of them, at the expense of other subcellular organelles. The diagnosis of oncocytoma is established by the ultrastructural demonstration of the abnormal abundance of mitochondria.

Ultrastructure of musculature of the marginal hooklets of Macrogyrodactylus congolensis, a monogenean skin parasite from the catfish Clarias gariepinus

2011 ◽  
Vol 56 (2) ◽  
Author(s):  
Safaa Arafa
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clarias Gariepinus ◽  
Distal Region ◽  
Proximal Region ◽  
Marginal Hooklet ◽  
Transmission Electron ◽  
First Time ◽  
Macrogyrodactylus Congolensis

AbstractThe musculature of the marginal hooklets of adult Macrogyrodactylus congolensis (Prudhoe, 1957) Yamaguti, 1963 has been studied. Each marginal hooklet of M. congolensis is associated with three pairs of muscles. The possible role of these muscles in the operation of the marginal hooklet is discussed. Transmission electron microscopy has been used for the first time to study the marginal hooklets of M. congolensis. The handle articulates with the blade in the region of the guard. Internally, the handle, the proximal region of the blade in the articulation region and the distal pointed region of the blade consist of three layers. Distal to the articulation region, the blade consists of four layers with differing electron densities. A cavity is associated with the distal region of the blade and the handle. A cyton containing secretory bodies of different sizes and shapes was found in association with each marginal hooklet. The possible function of these secretions is discussed.

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