Mycoparasitic relationships. III. Parasitism of Physalospora obtuse by Calcarisporium parasiticum

1977 ◽  
Vol 55 (2) ◽  
pp. 198-207 ◽  
Author(s):  
H. C. Hoch
Keyword(s):  
Electron Microscopy ◽  
Growth Factors ◽  
Nutrient Uptake ◽  
Germ Tube ◽  
Light And Electron Microscopy ◽  
Large Pore ◽  
Host Parasite ◽  
Hyphal Contact

The host–parasite interaction between Physalospora obtusa and the biotrophic contact mycoparasite Calcarisporium parasiticum was studied by light and electron microscopy. After hyphal contact between the two fungi, a contact cell was delimited by a septum in the germ tube apex of C. parasiticum. Subsequently, a portion of the appressed walls of the host–parasite interface was dissolved, creating a large pore through which cytoplasmic exchange occurred. The results of this study explain, in part, how increased nutrient uptake from the host by the parasite is accomplished and dispells the hypothesis that the contact cell increases the permeability of the host plasmalemma to nutrients and required growth factors.

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.

Host – parasite relationships between the fungus Leptosphaerulina crassiasca and peanut

1992 ◽  
Vol 70 (9) ◽  
pp. 1724-1733 ◽  
Author(s):  
Mei-Lee Wu ◽  
Richard T. Hanlin
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Germ Tube ◽  
Light And Electron Microscopy ◽  
Host Cells ◽  
Detached Leaves ◽  
Host Cell Wall ◽  
Host Parasite ◽  
Germ Tubes ◽  
Infection Hypha

The mode of penetration and infection of the peanut leaf by Leptosphaerulina crassiasca were studied by means of light and electron microscopy. The attachment of the multicellular ascospores to the leaf surface was by a mucilagenous sheath that covered the ascospores at maturity. This sheath expanded rapidly in moisture and it extended along the germ tube as it elongated. Two types of germ tubes appeared to be formed, a short one and a relatively long one. Short germ tubes were not delimited by septa, and they penetrated the cuticle and host epidermal cell wall directly without appressorium formation. Penetration occurred 2–6 h after inoculation. The wall was breached by a relatively broad infection hypha that expanded in width inside the host cell wall. The lack of mechanical rupture at the infection site indicated that penetration may involve enzymatic activity. Intracellular hyphae were present in the epidermal cells, but only intercellular hyphae occurred in the palisade and spongy mesophyll tissues. The intercellular hyphae were frequently appressed to the outer surface of the host cell wall. Infected areas rarely exceeded 1 mm in diameter, and they were only sparsely colonized by hyphae of the pathogen. Host cells in the vicinity of hyphae underwent senescence and death. One to 2 months after inoculation, pseudothecia formed in the dead tissues of detached leaves. In some instances the presence of penetration hyphae by short germ tubes induced the formation of a papilla inside the host cell wall, which either restricted growth of the infection hypha or resulted in the death of the germ tube and the cell from which it arose. Long germ tubes were delimited by simple septa and they terminated in an appressorium; however, details of their behavior were not studied. Key words: Arachis hypogaea, Ascomycotina, Dothideales, leaf scorch, pepper spot.

Host-parasite interface of the flukeCollyriclum faba (Bremser in Schmalz, 1831) as revealed by light and electron microscopy

1982 ◽  
Vol 68 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Harvey D. Blankespoor ◽  
Darwin D. Wittrock ◽  
John Aho ◽  
Gerald W. Esch
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Host Parasite

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 Morphology of Vacuolated Cells in the Liver Following Administration of Vitamin A.

1973 ◽  
Vol 31 ◽  
pp. 408-409
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Electron Microscopy ◽  
Body Weight ◽  
Vitamin A ◽  
Light And Electron Microscopy ◽  
Liver Cells ◽  
Prominent Feature ◽  
Vascular Space ◽  
Vacuolated Cell ◽  
Vacuolated Cells ◽  
Vacuolated Cytoplasm

Vacuolated cells in the liver of young rats were studied by light and electron microscopy following the administration of vitamin A (200 units per gram of body weight). Their characteristics were compared with similar cells found in untreated animals.In rats given vitamin A, cells with vacuolated cytoplasm were a prominent feature. These cells were found mostly in a perisinusoidal location, although some appeared to be in between liver cells (Fig. 1). Electron microscopy confirmed their location in Disse's space adjacent to the sinusoid and in recesses between liver cells. Some appeared to be bordering the lumen of the sinusoid, but careful observation usually revealed a tenuous endothelial process separating the vacuolated cell from the vascular space. In appropriate sections, fenestrations in the thin endothelial processes were noted (Fig. 2, arrow).

The Pathogenesis of Experimental Mycotic Encephalitis

1969 ◽  
Vol 27 ◽  
pp. 356-357
Author(s):  
James A. Swenberg ◽  
Adalbert Koestner ◽  
R.P. Tewari
Keyword(s):  
Electron Microscopy ◽  
Pathogenetic Mechanisms ◽  
Host Parasite

Previous investigations of pathogenetic mechanisms in mycotic encephalitis have been restricted to light microscopic and mycologic approaches. In this study, electron microscopy was utilized to determine the mode of vascular penetration and the cellular and subcellular host-parasite interrelationships in brains of mice infected with Oidiodendron kalrai. This newly isolated fungus was selected because of its ability to consistently produce encephalitis with gross and microscopic lesions similar to those observed in naturally occuring mycoses.

Examination of Schistosome Cercariae and Schistosomules by Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 50-51
Author(s):  
D. Johnson ◽  
P. Moriearty
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Light Microscopy ◽  
Surface Structure ◽  
Extensive Study ◽  
Scanning Microscopy ◽  
Host Parasite ◽  
Conventional Electron Microscopy ◽  
Scanning Electron

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.

Control of Autogenous Vein Grafts Prior to Reimplantation, By Electron Microscopy

1972 ◽  
Vol 30 ◽  
pp. 106-107
Author(s):  
John H. L. Watson ◽  
John L. Swedo ◽  
M. Vrandecic
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Physiological Saline ◽  
Experimental Conditions ◽  
Vein Grafts ◽  
Arterial Blood ◽  
Saphenous Veins ◽  
Autogenous Vein ◽  
Control Of Parameters ◽  
Post Implantation

The ambient temperature and the nature of the storage fluids may well have significant effects upon the post-implantation behavior of venus autografts. A first step in the investigation of such effects is reported here. Experimental conditions have been set which approximate actual operating room procedures. Saphenous veins from dogs have been used as models in the experiments. After removal from the dogs the veins were kept for two hours under four different experimental conditions, viz at either 4°C or 23°C in either physiological saline or whole canine arterial blood. At the end of the two hours they were prepared for light and electron microscopy. Since no obvious changes or damage could be seen in the veins by light microscopy, even with the advantage of tissue specific stains, it was essential that the control of parameters for successful grafts be set by electron microscopy.

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