The morphology of the attachment and probable feeding site of the nematode Trichuris muris (Schrank, 1788) Hall, 1916

1978 ◽  
Vol 56 (9) ◽  
pp. 1889-1905 ◽  
Author(s):  
T. D. G. Lee ◽  
K. A. Wright
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Membrane ◽  
Lipid Droplets ◽  
Syncytium Formation ◽  
Basal Membrane ◽  
Trichuris Muris ◽  
Feeding Site ◽  
Transmission Electron ◽  
Epithelial Sheet

The 'tunnel' within which the nematode Trichuris muris is contained was examined by light, scanning, and transmission electron microscopy. The amount of worm covered by the tunnel varied with age. Young larval worms were completely embedded in the host's intestinal mucosa whereas older larvae and adults had part, if not all, of the posterior region protruding into the lumen. All worms were found to have heads embedded in the tissue and in no cases were whole worms found free in the lumen.The 'tunnel' was shown to be a syncytial protoplasmic mass with recognizable cellular elements such as nuclei, lipid droplets, mitrochondria, and mucous droplets anteriorly whereas more distal to the head these elements became increasingly scarce and degenerated. The syncytium is bordered apically, laterally, and basally by cell membrane. The basal lamina can be identified beneath the basal membrane of the syncytium indicating that syncytium formation occurs in the epithelial sheet only and does not extend into the lamina propria. Evidence suggests that the nematode initially induces a syncytium about its head, feeds on the syncytial cytoplasm, and then moves on to initiate extension of the syncytium. The result of this movement is a 'tunnel' snaking across the caecum and colon.

Cleavage in the chick embryo

Development ◽  
1978 ◽  
Vol 43 (1) ◽  
pp. 55-69
Author(s):  
Ruth Bellairs ◽  
F. W. Lorenz ◽  
Tania Dunlap
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chick Embryo ◽  
Cell Membrane ◽  
Cortical Region ◽  
Chick Embryos ◽  
Membrane Formation ◽  
Transmission Electron

Chick embryos ranging from the stage of first cleavage to that of about 700 cells were removed from the oviduct and examined by transmission electron microscopy. Beneath the cell membrane is a yolk-free cortical region containing microfilaments. Beneath this lies cytoplasm which contains yolk spheres which are graded in size, the dorsal ones being smaller than the ventral ones. The subgerminal periblast possesses a greater proportion of yolk to cytoplasm than do the cells proper, but it merges with the cytoplasm at the incomplete borders of the ‘open’ cells. Specialized accumulations of membranes lie in the marginal periblast, and it is suggested that they play a role in cell membrane formation.

The effect of praziquantel on the ultrastructure of Schistosoma margrebowiei

1991 ◽  
Vol 65 (2) ◽  
pp. 79-88 ◽  
Author(s):  
A. H. H. Awad ◽  
A. J. Probert
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Immune System ◽  
Neck Region ◽  
Basal Membrane ◽  
Host Cells ◽  
Time Intervals ◽  
Entire Surface ◽  
Transmission Electron ◽  
Severe Erosion

ABSTRACTThe effect of various concentrations of praziquantel at different time intervals post-treatment on the ultrastructure of Schistosoma margrebowiei using scanning and transmission electron microscopy has been examined. The major changes involved blebbing of the entire surface tegument of both sexes (although more marked in males) together with vacuolation of the basal membrane accompanied by the development of membraneous whorls. These effects were progressively more marked with increased concentration and time of exposure resulting in severe erosion of the tubercles and collapse of the sensory organelles. Exposure of the underlying tegumental tissue resulted and paralysis and contraction of the suckers and neck region was apparent. Disruption of the subtegumental musculature and the appearance of vacuolation and membraneous whorl formation were seen. The gastrodermis was similarly affected and the S4 cells of the vitelline gland showed protein disruption of the vitelline droplets. Host cells were seen adhering to the surface of the worms following drug treatment and the synergism between PZQ and the action of the hosts immune system has been discussed.

scholarly journals Influence of uremia and peritoneal dialysis on mesothelial cells of the peritoneum

2002 ◽  
Vol 59 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Dusan Trpinac ◽  
Biljana Stojimirovic ◽  
Miljana Obradovic ◽  
Drago Milutinovic ◽  
Dragan Obradovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Renal Failure ◽  
Peritoneal Dialysis ◽  
Basal Membrane ◽  
Mesothelial Cells ◽  
Endoplasmatic Reticulum ◽  
Terminal Renal Failure ◽  
Transmission Electron ◽  
Different Shapes

The aim of the study was to investigate the morphology of mesothelial cells of the peritoneum of patients with terminal renal failure (TRF), taken by the biopsy immediately before the onset of peritoneal dialysis (PD), and to compare it with the findings in patients with PD. The samples were prepared in the way standard for light microscopy and transmission electron microscopy. In patients with TRF intracytoplasmatic inclusions could be observed, unusual protrusions of mesothelial apical surfaces, deformation of mesothelial cells and their detachment from the basal membrane, as well as the dilatated cisternae of granulated endoplasmatic reticulum with filamentous structures in some of them. In patients on PD cytoplasmic protrusions of different shapes and contents were observed at the surface of mesothelial cells, multiplication of basal membrane, occurrence of young forms of mesothelial cells as well as the detachment of those cells from the basal lamina.

Energy metabolism of cells in the macula flava of the newborn vocal fold from the aspect of mitochondrial microstructure

2021 ◽  
pp. 1-6
Author(s):  
K Sato ◽  
S Chitose ◽  
K Sato ◽  
F Sato ◽  
T Ono ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Metabolism ◽  
Vocal Fold ◽  
Lipid Droplets ◽  
Vocal Folds ◽  
Mitochondrial Matrix ◽  
Double Membrane ◽  
Transmission Electron ◽  
Bounded Body

Abstract Objective Cells in the vocal fold of maculae flavae are likely to be tissue stem cells. Energy metabolism of the cells in newborn maculae flavae was investigated from the aspect of mitochondrial microstructure. Method Five normal newborn vocal folds were investigated under transmission electron microscopy. Results Mitochondria consisted of a double membrane bounded body containing matrices and a system of cristae. However, these membranes were ambiguous. In each mitochondrion, the lamellar cristae were sparse. Intercristal space was occupied by a mitochondrial matrix. Some mitochondria had fused to lipid droplets and rough endoplasmic reticulum, and both the mitochondrial outer and inner membranes had incarcerated and disappeared. Conclusion The features of the mitochondria of the cells in the newborn maculae flavae showed that their metabolic activity and oxidative phosphorylation were low. The metabolism of the cells in the newborn maculae flavae seems to be favourable to maintain the stemness and undifferentiation of the cells.

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.

scholarly journals New flat embedding method for transmission electron microscopy reveals an unknown mechanism of tetracycline

2019 ◽  
Author(s):  
Michaela Wenzel ◽  
Marien P. Dekker ◽  
Biwen Wang ◽  
Maroeska J. Burggraaf ◽  
Wilbert Bitter ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Membrane ◽  
Large Scale ◽  
Public Health Problem ◽  
Fixation Method ◽  
Bacterial Cells ◽  
Embedding Method ◽  
Transmission Electron ◽  
Flat Embedding

AbstractTransmission electron microscopy (TEM) is an important imaging technique in bacterial research and requires ultrathin sectioning of resin embedding of cell pellets. This method consumes milli- to deciliters of culture and results in sections of randomly orientated cells. For rod-shaped bacteria, this makes it exceedingly difficult to find longitudinally cut cells, which precludes large-scale quantification of morphological phenotypes. Here, we describe a new fixation method using either thin agarose layers or carbon-coated glass surfaces that enables flat embedding of bacteria. This technique allows for the observation of thousands of longitudinally cut rod-shaped cells per single section and requires only microliter culture volumes. We successfully applied this technique to Gram-positive Bacillus subtilis, Gram-negative Escherichia coli, the tuberculosis vaccine strain Mycobacterium bovis BCG, and the cell wall-lacking mycoplasma Acholeplasma laidlawii. To assess the potential of the technique to quantify morphological phenotypes, we examined cellular changes induced by a panel of different antibiotics. Surprisingly, we found that the ribosome inhibitor tetracycline causes significant deformations of the cell membrane. Further investigations showed that the presence of tetracycline in the cell membrane changes membrane organization and affects the peripheral membrane proteins MinD, MinC, and MreB, which are important for regulation of cell division and elongation. Importantly, we could show that this effect is not the result of ribosome inhibition but is a secondary antibacterial activity of tetracycline that has defied discovery for more than 50 years.SignificanceBacterial antibiotic resistance is a serious public health problem and novel antibiotics are urgently needed. Before a new antibiotic can be brought to the clinic, its antibacterial mechanism needs to be elucidated. Transmission electron microscopy is an important tool to investigate these mechanisms. We developed a flat embedding method that enables examination of many more bacterial cells than classical protocols, enabling large-scale quantification of phenotypic changes. Flat embedding can be adapted to most growth conditions and microbial species and can be employed in a wide variety of microbiological research fields. Using this technique, we show that even well-established antibiotics like tetracycline can have unknown additional antibacterial activities, demonstrating how flat embedding can contribute to finding new antibiotic mechanisms.

Topography and Ultrastructure of the tegument of adultSchistosoma mekongi

Parasitology ◽  
1984 ◽  
Vol 89 (3) ◽  
pp. 511-521 ◽  
Author(s):  
P. Sobhon ◽  
E. S. Upatham ◽  
Diane J. McLaren
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Outer Membrane ◽  
Inclusion Bodies ◽  
Unique Feature ◽  
Basal Membrane ◽  
The Body ◽  
Transmission Electron ◽  
Schistosoma Mekongi ◽  
Membrane Infoldings

SUMMARYThe tegument of adultSchistosoma mekongihas been studied by both scanning and transmission electron microscopy. The gross surface topography of the parasite resembles that ofS. japonicum, in that branched ridges, microvilli and sensory papillae predominate; such characteristics distinguish these two species from the non-oriental schistosomes. A unique feature ofS. mekongi, however, is the numerous pleomorphic protruberances which are concentrated particularly on the middle three-fourths of the body surface. Transmission electron microscopy has revealed that these protruberances enclose bundles of microfilaments which appear to insert into the tegumental outer membrane. The microfilaments are suggested to have a supportive or stabilizing function, and may compensate for the absence of more typical crystalline spines. The tegumental outer membrane is typically heptalaminate in section, while the basal membrane infoldings are surrounded by concentrations of mitochondria. Three types of tegumental inclusion bodies have been recognized. Discoid bodies and membraneous bodies are morphologically identical to those described in all other schistosome species, except that the latter inclusions have been seen connected to each other and to the tegumental outer membrane by unique channels lined with trilaminate membrane. The third inclusion takes the form of spherical, lucent vesicles containing membrane fragments; these may represent the remains of spent membraneous bodies.

Ultrastructure of actinorhizal root nodules of Chamaebatia foliolosa (Rosaceae)

1984 ◽  
Vol 62 (8) ◽  
pp. 1697-1707 ◽  
Author(s):  
William Newcomb ◽  
Rod M. Heisey
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lipid Droplets ◽  
Root Nodules ◽  
Host Cells ◽  
Infected Host ◽  
Transmission Electron ◽  
Polysaccharide Capsule

The structure of the root nodules of Chamaebatia foliolosa Benth. (Rosaceae) has been studied by optical and transmission electron microscopy. The prokaryotic endophyte exhibits two morphological forms: septate hyphae and nonseptate elliptically shaped endophytic vesicles. This microorganism resembles the actinomyceteous endophytes of other actinorhizal root nodules especially those present in Ceanothus, Dryas, and Purshia. The endophyte is always surrounded by a polysaccharide capsule and possesses glycogen granules, lipid droplets, and prominent nucleoids. The infected host cells contain prominent lobed nuclei, numerous small vacuoles, and many plastids which possess numerous granular inclusions and osmiophilic droplets. No endophytic sporangia were observed in these nodules.

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