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.

scholarly journals Cryptococcus neoformans: Diagnostic Dilemmas, Electron Microscopy and Capsular Variants

2018 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Monica Birkhead ◽  
Serisha D. Naicker ◽  
Nozuko P. Blasich ◽  
Ivy Rukasha ◽  
Juno Thomas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cerebrospinal Fluid ◽  
Cryptococcus Neoformans ◽  
Control Culture ◽  
Test Results ◽  
Cryptococcal Antigen ◽  
Transmission Electron ◽  
Staining Protocol ◽  
Capsular Material

Two cases of cryptococcal meningitis went undetected by a cryptococcal antigen (CrAg) lateral flow assay on blood in a reflex CrAg screen-and-treat programme in South Africa, although Cryptococcus neoformans was identified by culturing the cerebrospinal fluid specimens. Further investigations into these discordant diagnostic results included multilocus sequence typing (which showed no mutations in the CAP59 gene) and transmission electron microscopy using a capsule-staining protocol (which revealed a >50% reduction in capsular material in both cases, relative to a control culture). A multi-disciplinary approach for resolving discordant diagnostic test results is recommended.

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.

Ultrastructural evidence for the existence of actinorhizal symbioses in the late Pleistocene

1980 ◽  
Vol 58 (15) ◽  
pp. 1612-1620 ◽  
Author(s):  
Dwight Baker ◽  
Norton G. Miller
Keyword(s):  
Electron Microscopy ◽  
Root Nodule ◽  
Root Nodules ◽  
Eastern North America ◽  
Independent Evidence ◽  
Qualitative And Quantitative ◽  
Ultrastructural Evidence ◽  
Shepherdia Canadensis ◽  
Nodule Endophytes ◽  
Scanning Electron

Macrofossil actinorhizal root nodules discovered in sediments about 11 500 radiocarbon years old in northern Vermont, U.S.A., were studied by scanning electron microscopy. Evidence of an endophytic microsymbiont was observed within the cortex of the fossil nodules. A comparative study as undertaken using root nodules from species of Alnus, Dryas, Elaeagnus, Myrica, Shepherdia, and Vicia native to eastern North America in an effort to determine the identity of the fossils. From qualitative and quantitative differences observed among the root nodule endophytes, it was concluded that the fossil nodules contained actinomycetes morphologically similar to those of extant Elaeagnaceae. The fossils are probably from plants of Elaeagnus commutata and (or) Shepherdia canadensis based on independent evidence of the representation of these species in the plant macrofossil assemblage.

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.

Fine structure of the microsymbiont of the actinorhizal root nodules of mountain mahogany (Cercocarpus ledifolius, family Rosaceae)

1989 ◽  
Vol 67 (1) ◽  
pp. 116-120 ◽  
Author(s):  
Susan M. Wood ◽  
William Newcomb ◽  
David Nelson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Root Nodules ◽  
Single Electron ◽  
Transmission Electron ◽  
Cercocarpus Ledifolius ◽  
Scanning Electron

Root nodules of Cercocarpus ledifolius Nutt. (mountain mahogany) were studied by light microscopy, scanning electron microscopy, and transmission electron microscopy to confirm the bacterial nature of the microsymbiont and to determine the morphology of the symbiotic vesicles. The microsymbiont is an actinomycete having two morphologies: septate hyphae (ca. 0.5 μm diam.) and ovoid- or elliptical-shaped nonseptate symbiotic vesicles (2.8 × 3.9 μm). Many of the symbiotic vesicles contain a single, electron-dense ovoid- or spherical-shaped structure, measuring 0.26 μm, whose function is unknown. The actinomycete is surrounded by a capsule that has electron-dense droplets in regions near hyphae. No spores or sporangia were observed in these nodules.

Ultrastructure of the host–pathogen interface in Arabidopsis thaliana leaves infected by the downy mildew Hyaloperonospora parasitica

2004 ◽  
Vol 82 (7) ◽  
pp. 1001-1008 ◽  
Author(s):  
C W Mims ◽  
E A Richardson ◽  
B F Holt III ◽  
J L Dangl
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Arabidopsis Thaliana ◽  
High Pressure ◽  
Cell Wall ◽  
Host Cell ◽  
Hyaloperonospora Parasitica ◽  
Transmission Electron ◽  
Host Pathogen ◽  
Host Cell Wall

Transmission electron microscopy was used to examine the host–pathogen interface in Arabidopsis thaliana (L.) Heynh. leaves infected by the biotrophic downy mildew pathogen Hyaloperonospora parasitica (Pers.:Fr.) Constant. Both conventionally fixed as well as high-pressure frozen samples were examined. Excellent preservation of the host–pathogen interface was obtained in many of our high-pressure frozen samples and provided information not available in conventionally fixed samples. Mature haustoria of H. parasitica were distinctly pyriform in shape. A small collar of host cell wall material surrounded the neck of each haustorium near the host cell wall penetration site. The presence of callose in collars was demonstrated using immunogold labeling with a monoclonal antibody specific for (1→3)-β-glucans. The body of each haustorium was ensheathed by an invaginated portion of the invaded host-cell plasma membrane known as the extrahaustorial membrane. Lying between this membrane and the haustorial wall was a layer of electron-dense material known as the extrahaustorial matrix (EHM). The EHM typically was thicker at the distal end of a haustorium than at the proximal end. The surface of the EHM covered by the extrahaustorial membrane was highly irregular in outline. Considerable vesicular activity was observed in association with the extrahaustorial membrane.Key words: transmission electron microscopy, high-pressure freezing, haustoria, Peronospora parasitica.

Sign in / Sign up

Export Citation Format

Share Document