Scanning and transmission electron microscopy of ovine mesenteric arteries infected with first-generation meronts of Sarcocystis tenella

1982 ◽  
Vol 60 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Clarence A. Speer ◽  
J. P. Dubey
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
First Generation ◽  
Mesenteric Arteries ◽  
Host Cells ◽  
Elastic Membrane ◽  
Vessel Lumen ◽  
Transmission Electron ◽  
Sarcocystis Tenella ◽  
Tunica Intima

First-generation meronts of Sarcocystis tenella were found within subendothelial cells between the endothelium and internal elastic membrane of mesenteric arteries. At 14 and 16 days postinoculation (DPI), host cells with mature meronts were enlarged, measuring 25.6 × 22 μm (16.4–35 × 4.4–28.5 μm; n = 17), which caused the endothelium to protrude into the vessel lumen. In mesenteric arteries, protuberances measured 37.4 × 29.7 μm (32–57 × 16.5–47 μm; n = 15) and extended 16.8 μm (12–27 μm; n = 12) into the vessel lumen. Merozoites in meronts measured 5.3 × 1.7 μm (4.5–5.5 × 1.5–1.8 μm; n = 20); free merozoites were 5.5 × 1.5 μm (4.8–6 × 1.3–1.7 μm; n = 18). At 16 DPI many of the endothelial cells covering protuberances as well as many of the host cells had sloughed from the tunica intima of the mesenteric arteries which exposed relatively large areas, 189.5 μm (50–350 μm; n = 15) in diameter, of the internal elastic membrane.

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.

Evaluation of a Self-limiting Concept in Dentinal Caries Removal

2006 ◽  
Vol 85 (3) ◽  
pp. 282-286 ◽  
Author(s):  
N.R.F.A. Silva ◽  
R.M. Carvalho ◽  
L.F. Pegoraro ◽  
F.R. Tay ◽  
V.P. Thompson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
First Generation ◽  
Tactile Sensation ◽  
Mechanical Removal ◽  
Transmission Electron ◽  
Etch And Rinse ◽  
Caries Removal ◽  
Bond Strengths ◽  
Self Etch

The mechanical removal of dentinal caries traditionally involves the use of tactile sensation and/or caries-indicating dyes. This study tested the hypothesis that self-limiting polymer burs are as effective as conventional carbide burs in creating substrates for dentin bonding. Carious dentin from extracted human molars was removed with carbide or polymer burs, with dental explorer hardness as the end-point for caries removal. Dentin substrates were bonded with etch-and-rinse or self-etch adhesives and prepared for microtensile bond testing and transmission electron microscopy. For each bur type, there was no difference in bond strength between adhesives. However, the polymer bur surface exhibited significantly lower bond strengths than the carbide bur, and both were lower than flat, non-carious dentin controls. TEM revealed areas of incompletely removed, denatured caries-infected dentin in the polymer bur specimens. These first-generation polymer burs might best be utilized for deep caries removal where pulpal exposure is a concern.

Schizophyllum commune Fr. as a destructive mycoparasite

1978 ◽  
Vol 24 (7) ◽  
pp. 780-784 ◽  
Author(s):  
S. S. Tzean ◽  
R. H. Estey
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Host Cell ◽  
Cell Walls ◽  
Schizophyllum Commune ◽  
Host Cells ◽  
Transmission Electron ◽  
Reaction Region

Schizophyllum commune Fr. was shown, by light, scanning, and transmission electron microscopy, to be a destructive mycoparasite on several phytopathogenic and nematode-trapping fungi. The hyphae of S. commune coiled around host hyphae and fruiting structures and penetrated them by means of either unspecialized hyphae or by penetration pegs that developed from terminal appressoria. The host cell walls were usually chemically degraded after which the parasite grew through an electron-dense, papillate, reaction region and its underlying membrane(s) to produce trophic hyphae inside the host cells.

scholarly journals Arrabidaea chicaHexanic Extract Induces Mitochondrion Damage and Peptidase Inhibition onLeishmaniaspp.

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Igor A. Rodrigues ◽  
Mariana M. B. Azevedo ◽  
Francisco C. M. Chaves ◽  
Celuta S. Alviano ◽  
Daniela S. Alviano ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Host Cells ◽  
Peptidase Activity ◽  
Active Fraction ◽  
Transmission Electron ◽  
Arrabidaea Chica

Currently available leishmaniasis treatments are limited due to severe side effects.Arrabidaea chicais a medicinal plant used in Brazil against several diseases. In this study, we investigated the effects of 5 fractions obtained from the crude hexanic extract ofA. chicaagainstLeishmania amazonensisandL. infantum, as well as on the interaction of these parasites with host cells. Promastigotes were treated with several concentrations of the fractions obtained fromA. chicafor determination of their minimum inhibitory concentration (MIC). In addition, the effect of the most active fraction (B2) on parasite’s ultrastructure was analyzed by transmission electron microscopy. To evaluate the inhibitory activity of B2 fraction onLeishmaniapeptidases, parasites lysates were treated with the inhibitory and subinhibitory concentrations of the B2 fraction. The minimum inhibitory concentration of B2 fraction was 37.2 and 18.6 μg/mL forL. amazonensisandL. infantum, respectively. Important ultrastructural alterations as mitochondrial swelling with loss of matrix content and the presence of vesicles inside this organelle were observed in treated parasites. Moreover, B2 fraction was able to completely inhibit the peptidase activity of promastigotes at pH 5.5. The results presented here further support the use ofA. chicaas an interesting source of antileishmanial agents.

Ultrastructure of the host-parasite interaction in leaves of Duchesnea indica infected by the rust fungus Frommeëla mexicana var. indicae as revealed by high pressure freezing

2001 ◽  
Vol 79 (1) ◽  
pp. 49-57 ◽  
Author(s):  
C W Mims ◽  
C Rodriguez-Lother ◽  
E A Richardson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Rust Fungus ◽  
Freeze Substitution ◽  
Transfer Cells ◽  
Host Cells ◽  
High Pressure Freezing ◽  
Transmission Electron ◽  
Duchesnea Indica

A combination of scanning and transmission electron microscopy was used to examine the host-pathogen relationship in leaves of Duchesnea indica (Andrz) Focke infected by the rust fungus Frommeëla mexicana var. indicae McCain & Hennen. Samples for transmission electron microscopy were prepared using high pressure freezing followed by freeze substitution. This protocol provided excellent preservation of both host cells and fungal haustoria. Each haustorium of F. mexicana var. indicae possessed a long slender neck with a neck band and an expanded body that contained two nuclei positioned close together. The haustorial body was lobed and sometimes even branched but lacked septa. Details of the extrahaustorial membrane that separated each haustorium from the cytoplasm of its host cell were particularly well preserved. Extensive labyrinth cell wall ingrowths developed around haustorial necks, as well as elsewhere, in infected cells. These ingrowths appeared to be identical to those present in plant transfer cells. Transfer cells are thought to be involved in intensive solute transfer over short distances. This appears to be the first report of the development of transfer cells in response to infection by a plant pathogenic fungus.Key words: haustoria, transfer cells, freeze substitution, electron microscopy.

scholarly journals Adherence of Giardia lambliaTrophozoites to Int-407 Human Intestinal Cells

2001 ◽  
Vol 8 (2) ◽  
pp. 258-265 ◽  
Author(s):  
M. Céu Sousa ◽  
C. A. Gonçalves ◽  
V. A. Bairos ◽  
J. Poiares-da-Silva
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ventral Surface ◽  
Host Cells ◽  
Intestinal Cells ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Vitro Model

ABSTRACT Attachment of Giardia lamblia trophozoites to enterocytes is essential for colonization of the small intestine and is considered a prerequisite for parasite-induced enterocyte dysfunction and clinical disease. In this work, coincubation of Giardiawith Int-407 cells, was used as an in vitro model to study the role of cytoskeleton and surface lectins involved in the attachment of the parasite. This interaction was also studied by scanning and transmission electron microscopy. Adherence was dependent on temperature and was maximal at 37°C. It was reduced by 2.5 mM colchicine (57%), mebendazole (10 μg/ml) (59%), 100 mM glucose (26%), 100 mM mannose (22%), 40 mM mannose-6-phosphate (18%), and concanavalin A (100 μg/ml) (21%). No significant modification was observed when Giardia was pretreated with cytochalasins B and D and with EDTA. Giardia attachment was also diminished by preincubating Int-407 cells with cytochalasin B and D (5 μg/ml) (16%) and by glutaraldehyde fixation of intestinal cells and ofG. lamblia trophozoites (72 and 100%, respectively). Ultrastructural studies showed that Giardia attaches to the Int-407 monolayer predominantly by its ventral surface. Int-407 cells contact trophozoites with elongated microvilli, and both trophozoite imprints and interactions of Giardia flagella with intestinal cells were also observed. Transmission electron microscopy showed that Giardia lateral crest and ventrolateral flange were important structures in the adherence process. Our results suggest a combination of mechanical and hydrodynamic forces in trophozoite attachment; surface lectins also seem to mediate binding and may be involved in specific recognition of host cells.

ENDOTHELIAL BASEMENT MEMBRANE PROTEOGLYCAN (PG) ALTERATIONS IN DEOXYCORTICOSTERONE (DOCA)-NaCl -INDUCED HYPERTENSIVE RAT MESENTERIC ARTERIES

1987 ◽  
Author(s):  
M Richardson ◽  
R M K W Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Basement Membrane ◽  
Cell Metabolism ◽  
Endothelial Permeability ◽  
Ruthenium Red ◽  
Mesenteric Arteries ◽  
Transmission Electron ◽  
Endothelial Basement Membrane ◽  
Endothelial Cell Metabolism

Hypertension is associated with increased endothelial permeability. This has been previously associated with endothelial desquamation or alterations in junctional architecture.To determine if this increase in endothelial permeability was associated with changes in the basement membrane, especially the heperan sulphate (HS) PG, ruthenium red-stained sections of the superior mesenteric arteries of DOCA-NaCl treated rats were examined by transmission electron microscopy. After 3 weeks of treatment, some rats were hypertensive (DOCA-H), but some remained normotensive(DOCA-N). The intimal PG distribution was compared between DOCA-H, DOCA-N, and untreated normotensive controls. Compared to untreated controls, in DOCA-H arteries there was a reduction in basement membrane, including HS, and a small increase in other PGs. In DOCA-N arteries there was a much smaller change in PGdisribution. In the DOCA-H rats, there was evidence of increased endothelial permeability as shown by sub-endothelial oedema, and an increase in the wet/dryweight ratio of the kidneys.It is therefore possible that hypertension induces changes in endothelial cell metabolism which affect the production or maintenance of the basement membrane. Since the changes were not observed in the DOCA-Narteries they are not a result of the treatment. HS is generally accepted to be involved in the control of endothelial permeability, thus the observed loss of HS from hypertensive arteries may result in the increased endothelial permeability.Supported by The Heart and Stroke Foundation of Ontario.

scholarly journals Confocal microscopy reveals alterations of thylakoids in Limnospira fusiformis during prophage induction

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Maryam Alsadat Zekri ◽  
Michael Schagerl ◽  
Johannes Schweichhart ◽  
Ingeborg Lang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
3D Visualization ◽  
Laser Scanning Microscopy ◽  
Host Cells ◽  
Strong Increase ◽  
Prophage Induction ◽  
Intact Cells ◽  
Transmission Electron

AbstractThe alkaliphilic cyanobacterium Limnospira fusiformis is an integral part in food webs of tropical soda lakes. Recently, sudden breakdowns of Limnospira sp. blooms in their natural environment have been linked to cyanophage infections. We studied ultrastructural details and prophage components in the laboratory by means of confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). For a comparison at the subcellular level, we included transmission electron microscopy (TEM) material of infected cells collected during a field survey. Compared to TEM, CLSM has the advantage to rapidly providing results for whole, intact cells. Moreover, many cells can be studied at once. We chemically induced lysogenic cyanophages by means of mitomycin C (MMC) treatments and studied the ultrastructural alterations of host cells. In parallel, the number of cyanophages was obtained by flow cytometry. After treatment of the culture with MMC, flow cytometry showed a strong increase in viral counts, i.e., prophage induction. CLSM reflected the re-organization of L. fusiformis with remarkable alterations of thylakoid arrangements after prophage induction. Our study provides a first step towards 3D visualization of ultrastructure of cyanobacteria and showed the high potential of CLSM to investigate viral-mediated modifications in these groups.

Ultrastructure of the Alnus crispa var. mollis Fern. root nodule endophyte

1975 ◽  
Vol 21 (7) ◽  
pp. 1058-1080 ◽  
Author(s):  
Maurice Lalonde ◽  
Roger Knowles
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Root Nodule ◽  
Root Nodules ◽  
Host Cells ◽  
Alnus Crispa ◽  
Transmission Electron ◽  
Host Cell Wall ◽  
Capsular Material ◽  
Nodule Endophytes

Nitrogen-fixing, field-obtained root nodules of the silky green alder were studied by transmission electron microscopy. The nodule endophyte exhibited a prokaryotic cytology and was present in two forms: the hypha (0.3–1.0 μm), which was branched and septate, and the vesicle (3–5 μm), which was also septate and developed at the parental hypha tip. Bacteria-like cells, previously observed in light microscopy studies, were not seen in the present work. The actinomycete-like endophyte penetrated through the host cell wall and became enveloped by a capsular material (0.1 μm), the whole being enclosed by host membranes. In some host cells, the endophyte appeared to lyse and become a mass of shrunken debris. The fine structure of the Alnus crispa var. mollis root nodule endophyte was found to be similar to that of other non-leguminous root nodule endophytes.

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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