The Plasmodiophoromycete parasitic on Heteranthera dubia

1983 ◽  
Vol 61 (1) ◽  
pp. 45-52 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Unit ◽  
Host Cells ◽  
Synaptonemal Complexes ◽  
Transmission Electron ◽  
Resting Spores ◽  
End To End ◽  
Host Parasite

Light and transmission electron microscopy were used to characterize representative stages of sporogenic plasmodia and resting spores of the plasmodiophorid parasite in roots of Heteranthera dubia (Jacq.) MacM. (water-stargrass). Cruciform nuclear divisions occurred in young plasmodia and noncruciform divisions occurred in more mature, transitional plasmodia. Prophase nuclei in transitional plasmodia contained synaptonemal complexes; noncruciform divisions were interpreted, therefore, as meiosis. Host–parasite interfaces were single unit membranes. Centrioles were paired end-to-end in plasmodia, but unpaired, single centrioles were in resting spores. Resting spores also contained crystalline bodies. Sporosori were disklike, consisted predominantly of single layers of resting spores, and were located at the periphery of host cells. Membranosorus heterantherae Ostenfeld and Peterson was considered the appropriate genus–species for the parasite, not Sorodiscus heterantherae Wernham.

Ultrastructural karyology of Spongospora subterranea (Plasmodiophoromycetes)

1992 ◽  
Vol 70 (6) ◽  
pp. 1228-1233 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Electron Microscopy ◽  
Single Unit ◽  
Spongospora Subterranea ◽  
Unit Membrane ◽  
Potato Tubers ◽  
Haploid Chromosome Number ◽  
Synaptonemal Complexes ◽  
Transmission Electron ◽  
Host Parasite ◽  
Section Analysis

Sporogenic (cystogenous) stages of development of Spongospora subterranea (Wallroth) Lagerheim f.sp. subterranea Tomlinson infecting potato tubers were examined with transmission electron microscopy. Volume of nuclei in transitional Plasmodia was 28.2 ± 8.3 μm3. Serial section analysis revealed 37 synaptonemal complexes, hence the haploid chromosome number was considered to be 37. Total length of synaptonemal complexes per nucleus was 74.6 ± 1.4 μm, with individual synaptonemal complexes ranging in length from 1.34 ± 0.07 μm to 3.48 ± 0.17 μm. No polycomplexes were observed in transitional nuclei. Electron-opaque thickenings of lateral elements occurred irregularly. Additional ultrastructural features of sporogenic plasmodia included end-to-end paired centrioles defining the poles of the nuclei and a host–parasite boundary of a single unit membrane. Key words: karyotype, Plasmodiophoromycetes, Spongospora, synaptonemal complex.

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.

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.

The life cycle of Lagena radicicola, an oomycetous parasite of wheat roots

1990 ◽  
Vol 68 (4) ◽  
pp. 813-824 ◽  
Author(s):  
D. J. S. Barr ◽  
N. L. Désaulniers
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Life Cycle ◽  
Root Hairs ◽  
Wheat Roots ◽  
Virus Like Particles ◽  
Transmission Electron ◽  
Resting Spores ◽  
Single Host ◽  
Infected Cells

Lagena radicicola Vanterpool & Ledingham is an obligate parasite inside root hairs and epidermal cells. It was cultured in a unifungal state on wheat in pots. The life cycle was examined by both light and transmission electron microscopy. The thallus developed inside a single host cell and formed either a single sporangium or one to four resting spores. Zoospore cleavage was completed in vesicles outside the root. The resting spores were similar to oospores in their development and cytology, but there was no evidence of cell fusion and sexuality. Virus-like particles were seen in 3- to 12-month-old cultures, and infected cells became degenerate. Key words: Oomycetes, ultrastructure, virus-like particles, biocontrol.

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.

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.

Eocronartium muscicola: a basidiomycetous moss parasite exploiting gametophytic transfer cells

1988 ◽  
Vol 66 (4) ◽  
pp. 762-770 ◽  
Author(s):  
E. W. A. Boehm ◽  
D. J. McLaughlin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transfer Cells ◽  
Transmission Electron ◽  
Host Parasite ◽  
Relationship Of ◽  
The Relationship ◽  
Gain Access ◽  
Scanning Electron

The host–parasite interface in Eocronartium muscicola, Auriculariales sensu lato, was examined histologically for 6 of the 21 reported moss hosts, using light microscopy, scanning electron microscopy, and transmission electron microscopy. A unique mode of fungal biotrophy was encountered in 5 of the 6 mosses analyzed, in which E. muscicola exploits gametophytic host transfer cells concomitant with varying degrees of supplantation of the moss sporophyte. Basidiocarps are restricted in these mosses to postfertilized archegonia, in which they are seen to associate with the sporophyte foot region, where they gain access to the host transfer cell nutritional interface. Basidiocarp ontogeny is presented as it relates to the development of the host–parasite interface. The relationship of E. muscicola to other simple-septate auricularioid taxa and the the Uredinales is discussed.

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