A cytological study of the development of Erysiphe graminis in its host barley, as influenced by the two fungicides ethirimol and propiconazole

1990 ◽  
Vol 68 (12) ◽  
pp. 2618-2628 ◽  
Author(s):  
Annerose Heller ◽  
Friedrich Grossmann ◽  
Burkhard Frenzel ◽  
Sigrun Hippe
Keyword(s):  
Electron Microscopy ◽  
Host Cell ◽  
Light And Electron Microscopy ◽  
Unknown Origin ◽  
Erysiphe Graminis ◽  
Dense Material ◽  
Ultrastructural Changes ◽  
Wall Thickening ◽  
Electron Dense Material ◽  
Host Parasite

Light and electron microscopy of barley epidermal cells treated with ethirimol or propiconazole and then inoculated with Erysiphe graminis f. sp. hordei showed the complex reaction of this host–parasite system to fungicides. The completely different biochemical modes of action of the two fungicides were reflected in the ultrastructural changes observed. Specific fungicidal effects could be distinguished from degenerative processes associated with senescence of untreated plants. For ethirimol, the first changes to be observed in the nucleus were blebbing of the outer nuclear membrane, invaginations into the nucleoplasm, and loss of the dark-staining material of nuclear pores. Later on, large areas of the cytoplasm were devoid of ribosomes. Moreover, electron-dense material was found in the perinuclear space and in cisternae of the endoplasmic reticulum. Round bodies, containing electron-dense material of unknown origin, appeared in the cytoplasm. Propiconazole, on the other hand, caused severe malformations of haustoria, host cell wall appositions, and wall thickening. The sheaths surrounding the haustoria were significantly enlarged, and vesicular and multivesicular bodies appeared in the extrahaustorial matrix. In later stages, degenerated haustoria were partially encapsulated by the host cell. Large, rectangular, electron-opaque structures, termed Fibrosinkörper, were observed in secondary hyphae. Both fungicides tested caused swelling of secondary hyphae. Key words: Erysiphe graminis f.sp. hordei, ethirimol, propiconazole, host–parasite system, cytology, electron microscopy.

The ultrastructure of M1-a-mediated resistance to powdery mildew infection in barley

1975 ◽  
Vol 53 (22) ◽  
pp. 2589-2597 ◽  
Author(s):  
H. H. Edwards
Keyword(s):  
Powdery Mildew ◽  
Host Cell ◽  
Electron Density ◽  
Epidermal Cells ◽  
Dense Material ◽  
Ultrastructural Changes ◽  
Electron Dense Material ◽  
Host Cytoplasm ◽  
Powdery Mildew Infection ◽  
Cell Protoplast

M1-a-mediated resistance in barley to invasion by the CR3 race of Erysiphe graminis f. sp. hordei does not occur in every host cell with the same speed and severity. In some cells ultrastructural changes within the host cell as a result of resistance will occur within 24 h after inoculation, whereas in other cells these changes may take up to 72 h. In some cells the ultrastructural changes are so drastic that they give the appearance of a hypersensitive death of the host cell, whereas in other cells the changes are very slight. In any case, at the end of these changes the fungus ceases growth. The ultrastructural changes occur in penetrated host epidermal cells as well as non-infected adjacent epidermal and mesophyll cells.The following ultrastructural changes have been observed: (1) an electron-dense material which occurs either free in the vacuole or adhering to the tonoplast (the material is granular or in large clumps); (2) an increased electron density of the host cytoplasm and nucleus; (3) a breakdown of the tonoplast so that the cytoplasmic constituents become dispersed throughout the cell lumen; and (4) the deposition of papillar-like material in areas other than the penetration site. The first three changes take place within the host cell protoplasts and are directly attributable to the gene M1-a. These changes are typical of stress or incompatibility responses and thus M1-a appears to trigger a generalized incompatibility response in the presence of race CR3. The papillar-like material occurs outside the host cell protoplast in the same manner as the papilla and probably is not directly attributable to M1-a.

Studies withBrugia pahangi. 14. Intrauterine development of the microfilaria and a comparison with other filarial species

1976 ◽  
Vol 50 (4) ◽  
pp. 251-257 ◽  
Author(s):  
Rosemary Rogers ◽  
D. S. Ellis ◽  
D. A. Denham
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Uterine Wall ◽  
Dense Material ◽  
Intrauterine Development ◽  
Brugia Pahangi ◽  
Electron Dense Material ◽  
Large Numbers ◽  
Egg Shells ◽  
Egg Shell

ABSTRACTThe intrauterine development ofBrugia pahangiembryos was followed from after fertilization to birth, using light and electron microscopy. The origin and development of the sheath of the microfilaria and its Possible role in the nutrition of the developing embryo were particularly investigated. Comparisons were drawn with the intrauterine development of other filarial species. The egg shell of theB. pahangiembryo js distinct from the oolemma and forms the sheath of the microfilaria. It is suggested that the electron dense material released by cells of the uterine wall and passing along the channels between the egg shells of adjacent embryos is nutritive. The death of large numbers of developing embryos in the central uterine Jumen is probably caused by overcrowding as their size rapidly increases, leading to nutritional deficiency.

scholarly journals Development and ultrastructure observations of secondary hyphae of Podosphaera leucotricha on apple cultivars of varying susceptibility to powdery mildew

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 425-428
Author(s):  
E. Rakhimova
Keyword(s):  
Electron Microscopy ◽  
Powdery Mildew ◽  
Light And Electron Microscopy ◽  
Dense Material ◽  
Podosphaera Leucotricha ◽  
Powdery Mildew Fungus ◽  
Full Complement ◽  
Apple Cultivars ◽  
Host Parasite

The development and ultrastructure feature of secondary hyphae of Podosphaera leucotricha were studied using light and electron microscopy. The percentage of development and length of secondary hyphae, differed in compatible and incompatible combinations. In compatible host-parasite combinations, hyphal cells of powdery mildew fungus contained a full complement of fungal organelles. There were differences of hyphal ultrastructure in compatible and incompatible host-parasite combinations, the main one was the appearance of dense material inside the nucleus, in the cytoplasm, and a few mitochondria.

Role of M Cells and Macrophages in the Entrance of Mycobacterium paratuberculosis into Domes of Ileal Peyer's Patches in Calves

1988 ◽  
Vol 25 (2) ◽  
pp. 131-137 ◽  
Author(s):  
E. Momotani ◽  
D. L. Whipple ◽  
A. B. Thiermann ◽  
N. F. Cheville
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Light And Electron Microscopy ◽  
Peyer's Patches ◽  
Dense Material ◽  
M Cells ◽  
Mycobacterium Paratuberculosis ◽  
Electron Dense Material ◽  
Acid Fast Bacilli

Ligated ileal loops of calves were inoculated with live and heat-killed Mycobacterium paratuberculosis and were examined by light and electron microscopy. At 5 hours after inoculation, acid-fast bacilli were in subepithelial macrophages, but not in M cells covering domes. At 20 hours, more than 50 acid-fast bacilli per cross section were in subepithelial macrophages in domes. Both living and heat-killed bacilli passed into domes. Addition of anti- M. paratuberculosis bovine scrum to the inoculum enhanced entry of bacteria into domes. By electron microscopy, intact bacilli with electron-transparent zones (peribacillary spaces) were in the supranuclear cytoplasm of M cells at 20 hours. M cells also contained vacuoles, including electron-dense material interpreted as degraded bacilli. Subepithelial and intraepithelial macrophages contained bacilli and degraded bacterial material in phagosomes. These results suggest that calf ileal M cells take up bacilli, and that subepithelial and intraepithelial macrophages secondarily accept bacilli or bacterial debris which are expelled from M cells.

Light and electron microscopy studies on the infection of tomato fruits by Botrytis cinerea

1980 ◽  
Vol 58 (12) ◽  
pp. 1394-1404 ◽  
Author(s):  
F.H. J. Rijkenberg ◽  
G. T. N. De Leeuw ◽  
K. Verhoeff
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Host Cell ◽  
Botrytis Cinerea ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Wall Material ◽  
Wall Thickening ◽  
Cell Organelles ◽  
Tomato Fruits

A light microscopy study of the host–parasite relationship of Botrytis cinerea on immature tomato fruits was combined with an electron microscopy examination. Both techniques indicate that the cuticle is dissolved enzymatically rather than ruptured mechanically. Inter- and intracellular hyphae have no apparent effect on the cuticle, but do break down wall material. If the penetration tube development is arrested after emerging from the cuticle into the wall, wall discolouration and wall thickening become evident and a considerable increase in host cell organelles below the penetration site is observed. A papilla is also apposited. At successful penetration, when the hypha emerges from the cell wall into the host cell, little cell wall discolouration at the infection site is evident, but the cytoplasm becomes degenerate. Further hyphal extension then occurs in the epidermis, killing more epidermal cells, and leading to collapse, but not penetration, of underlying tissue.

Ultrastructural changes associated with induced systemic resistance of cucumber to disease: host response and development of Colletotrichum lagenarium in systemically protected leaves

1988 ◽  
Vol 66 (6) ◽  
pp. 1028-1038 ◽  
Author(s):  
X. L. Xuei ◽  
U. Järlfors ◽  
J. Kuć
Keyword(s):  
Electron Microscopy ◽  
Host Cell ◽  
Host Response ◽  
Structural Changes ◽  
Induced Systemic Resistance ◽  
Light And Electron Microscopy ◽  
Systemic Resistance ◽  
Ultrastructural Changes ◽  
Mesophyll Cells ◽  
Before And After

Systemic resistance to anthracnose caused by Colletotricum lagenarium was induced in cucumber by inoculation with fungal conidia. Control and immunized leaves were examined by both light and electron microscopy before and after subsequent challenge with the fungus. Penetration through the epidermal wall was evident 36 h after challenge and was followed by hyphal proliferation and host-cell destruction in control tissues. Penetration was rarely seen in immunized tissues before 72 h, but at 24 h, invaginations of the appressorial wall were observed, as well as highly electron opaque epidermal walls beneath the appressoria. At 72 h, thin penetration pegs were seen within the dense host wall, and at 96 h, the peg was embedded within the underlying papilla and aggregates of callose-like material. Penetration through the epidermis was rare in immunized tissue, but when it was observed, development appeared to be similar to that in control leaves. Evidence is presented to show that ultra-structural changes in immunized tissues as well as in the fungus occur within 24 h after challenge of the host. There appears to be a correlation between the comparatively few lesions observed macroscopically in immunized leaves and the sparsity of successful penetrations into host mesophyll cells.

Visualization of changes in ciliary tip configuration caused by sliding displacement of microtubules in macrocilia of the ctenophore Beroe

1985 ◽  
Vol 79 (1) ◽  
pp. 161-179 ◽  
Author(s):  
S.L. Tamm ◽  
S. Tamm
Keyword(s):  
Electron Microscopy ◽  
Dense Material ◽  
Bend Angle ◽  
Two Dimensional ◽  
Electron Dense Material ◽  
Central Pair ◽  
Rest Position ◽  
Recovery Stroke ◽  
Dimensional Models ◽  
As If

Macrocilia from the lips of the ctenophore Beroe consist of multiple rows of ciliary axonemes surrounded by a common membrane, with a giant capping structure at the tip. The cap is formed by extensions of the A and central-pair microtubules, which are bound together by electron-dense material into a pointed projection about 1.5 micron long. The tip undergoes visible changes in configuration during the beat cycle of macrocilia. In the rest position at the end of the effective stroke (+30 degrees total bend angle), there is no displacement between the tips of the axonemes, and the capping structure points straight into the stomach cavity. In the sigmoid arrest position at the end of the recovery stroke (−60 degrees total bend angle), the tip of the macrocilium is hook-shaped and points toward the stomach in the direction of the subsequent effective stroke. This change in tip configuration is caused by sliding displacement of microtubules that are bound together at their distal ends. Electron microscopy and two-dimensional models show that the singlet microtubule cap acts as if it were hinged to the ends of the axonemes and tilted to absorb the microtubule displacement that occurs during the recovery stroke. The straight and hooked shapes of the tip are thought to help the ctenophore ingest prey.

scholarly journals Light and electron microscopy characteristics of the muscle of patients with SURF1 gene mutations associated with Leigh disease

2007 ◽  
Vol 61 (4) ◽  
pp. 460-466 ◽  
Author(s):  
M Pronicki ◽  
E Matyja ◽  
D Piekutowska-Abramczuk ◽  
T Szymańska-Dębińska ◽  
A Karkucińska-Więckowska ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lipid Accumulation ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Gene Mutations ◽  
Leigh Syndrome ◽  
Typical Feature ◽  
Ultrastructural Changes ◽  
Consistent Feature ◽  
Muscle Changes

Aims:Leigh syndrome (LS) is characterised by almost identical brain changes despite considerable causal heterogeneity. SURF1 gene mutations are among the most frequent causes of LS. Although deficiency of cytochrome c oxidase (COX) is a typical feature of the muscle in SURF1-deficient LS, other abnormalities have been rarely described. The aim of the present work is to assess the skeletal muscle morphology coexisting with SURF1 mutations from our own research and in the literature.Methods:Muscle samples from 21 patients who fulfilled the criteria of LS and SURF1 mutations (14 homozygotes and 7 heterozygotes of c.841delCT) were examined by light and electron microscopy.Results:Diffuse decreased activity or total deficit of COX was revealed histochemically in all examined muscles. No ragged red fibres (RRFs) were seen. Lipid accumulation and fibre size variability were found in 14 and 9 specimens, respectively. Ultrastructural assessment showed several mitochondrial abnormalities, lipid deposits, myofibrillar disorganisation and other minor changes. In five cases no ultrastructural changes were found. Apart from slight correlation between lipid accumulation shown by histochemical and ultrastructural techniques, no other correlations were revealed between parameters investigated, especially between severity of morphological changes and the patient’s age at the biopsy.Conclusion:Histological and histochemical features of muscle of genetically homogenous SURF1-deficient LS were reproducible in detection of COX deficit. Minor muscle changes were not commonly present. Also, ultrastructural abnormalities were not a consistent feature. It should be emphasised that SURF1-deficient muscle assessed in the light and electron microscopy panel may be interpreted as normal if COX staining is not employed.

Spermiogenesis and spermatozoon of the tapeworm Parabothriocephalus gracilis (Bothriocephalidea): Ultrastructural and cytochemical studies

2010 ◽  
Vol 55 (1) ◽  
Author(s):  
Lenka Šípková ◽  
Céline Levron ◽  
Mark Freeman ◽  
Tomáš Scholz
Keyword(s):  
Electron Microscopy ◽  
Anterior Extremity ◽  
Mature Spermatozoon ◽  
Dense Material ◽  
Apical Region ◽  
Cortical Microtubules ◽  
Electron Dense Material ◽  
Dense Granules ◽  
Cytoplasmic Extension ◽  
Transmission Electron

AbstractSpermiogenesis and spermatozoon ultrastructure of the tapeworm Parabothriocephalus gracilis were described using transmission electron microscopy (TEM). Spermiogenesis is characterized by the formation of a zone of differentiation with two centrioles associated with striated rootlets, and an intercentriolar body between them. The two flagella undergo a rotation of 90° until they become parallel to the median cytoplasmic extension with which they fuse. Electron-dense material is present in the apical region of the zone of differentiation in the early stages of spermiogenesis. This electron-dense material is characteristic for the orders Bothriocephalidea and Diphyllobothriidea. The mature spermatozoon contains two axonemes of the 9 + ‘1’ trepaxonematan pattern, nucleus, parallel cortical microtubules and electron-dense granules of glycogen. The anterior extremity of the spermatozoon exhibits a single helical electron-dense crested body 130 nm thick. One of the most interesting features is the presence of a ring of cortical microtubules surrounding the axoneme. This character has been reported only for species of the order Bothriocephalidea and may be unique in this cestode group.

scholarly journals Histopathological and Ultrastructural Changes in the Liver and Gills of the Killifish Aphanius Dispar (Cyprinodontidae) Exposed to Aflatoxin B1

2015 ◽  
Vol 20 (1) ◽  
pp. 1
Author(s):  
Horiya H. Al-Azri ◽  
Taher Ba-Omar ◽  
Abdulkadir Elshafie ◽  
Michael J Barry
Keyword(s):  
Electron Microscopy ◽  
Aflatoxin B1 ◽  
Light And Electron Microscopy ◽  
Ultrastructural Changes ◽  
Unusual Behavior ◽  
High Doses

Aflatoxin B1 (AFB1) is a mycotoxin which can cause serious toxicity to animals and humans.  The aim of this study was to investigate the effects of AFB1 in Aphanius dispar fish and measure residues in tissues after in vivo exposure. Aphanius dispar were fed diets containing 50, 100, 150 and 200 µg AFB1/kg for 10, 20 and 30 days. At the end of the experiment, the liver and gills were dissected out and processed for light and electron microscopy. During the experiment, no external changes or unusual behavior were observed in the fish. Histopathological and ultrastructural changes in liver appeared under all four treatments: 50, 100, 150 and 200 µg AFB1/kg. Gill tissues were affected at high doses of 100,150 and 200 µg AFB1/kg. Accumulation of AFB1 residues in liver and gill tissues was found to be related to a dose and duration of exposure.  

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