An electron microscope study of the intracellular hyphae of some smut fungi (Ustilaginales)

1970 ◽  
Vol 18 (3) ◽  
pp. 285 ◽  
Author(s):  
RA Fullerton
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Host Cell ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Smut Fungi ◽  
Sheath Formation ◽  
Host Cell Wall ◽  
Similar Appearance ◽  
Host Tissues

A number of species of systemic smut fungi have been examined. Hyphae occupy inter- and intracellular positions in the host tissues. Intracellular hyphae resemble haustoria in many respects. Host plasmalemmae are invaginated by invading hyphae, and encapsulations are formed. Material of similar appearance to the host cell wall is deposited within encapsulations and many hyphae are eventually completely ensheathed. A possible mechanism for sheath formation is suggested.

scholarly journals Cellular interaction of the smut fungus Ustacystis waldsteiniae

1995 ◽  
Vol 73 (6) ◽  
pp. 867-883 ◽  
Author(s):  
Robert Bauer ◽  
Franz Oberwinkler ◽  
Kurt Mendgen
Keyword(s):  
High Pressure ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Host Cell ◽  
Smut Fungus ◽  
Cellular Interaction ◽  
Smut Fungi ◽  
The Matrix ◽  
Host Cell Wall ◽  
Host Plasma Membrane

The cellular interaction between the smut fungus Ustacystis waldsteiniae and its host Waldsteinia geoides was analyzed by serial-section electron microscopy using chemically fixed and high-pressure frozen – freeze-substituted samples. After penetration, each haustorium extends a short distance into the host cell where it often forms up to three short lobes. The haustorium is wholly ensheathed by a prominent matrix. The matrix is a complex structure, differing significantly from that known of other fungal plant parasites: it is filled with amorphous, electron-opaque material in which membrane-bounded, coralloid vesicles are embedded. During the contact phase of the hypha with the host cell wall, vesicles with electron-opaque contents accumulate in the contact area of the hypha where they appear to fuse with the fungal plasma membrane and extrude their contents. Subsequently, the host cell wall increases in electron opacity and matrix material becomes deposited between host plasma membrane and host cell wall exactly at the ends of the altered areas in the host cell wall. The coralloid vesicles within the matrix, however, are of host origin: exocytosis of Golgi products into the matrix results in the formation of coralloid vesicular buds in the host plasma membrane. Subsequently, the buds seem to detach from the host plasma membrane to flow as coralloid vesicles into the matrix. Matrix development continues during penetration and after penetration at the haustorial tips. After host wall penetration, the fungal cell wall comes in contact with the matrix. The fungal component of the matrix may play a key role in the inducement of these transfer cell-like compartments in host cells responding to infection. Key words: freeze substitution, haustoria, high-pressure freezing, host–parasite interaction, smut fungi, Ustacystis waldsteiniae.

Relations of hyphae to host cells in smut galls caused by species of Tilletia, Tolyposporium, and Ustilago

1987 ◽  
Vol 65 (12) ◽  
pp. 2581-2591 ◽  
Author(s):  
E. S. Luttrell
Keyword(s):  
Host Cell ◽  
Pennisetum Glaucum ◽  
Host Cells ◽  
Smut Fungi ◽  
Differential Growth ◽  
Tilletia Caries ◽  
Transmission Electron ◽  
Infection Threads ◽  
Host Cell Wall ◽  
Host Tissues

Transmission electron microscopy demonstrated that the mycelium in developing galls induced by smut fungi in the Tilletiaceae (Tilletia caries on Triticum aestivum) and Ustilaginaceae (Ustilago nuda on Hordeum vulgare, U. maydis on Zea mays, and Tolyposporium penicillariae on Pennisetum glaucum) may be both intercellular and intracellular. In T. caries the mycelium is mostly intercellular, in U. nuda it is both intercellular and intracellular, and in U. maydis and T. penicillariae it is mostly intracellular. Unconstricted hyphae penetrate the host cell wall, invaginate the host plasmalemma, and become surrounded by a tubular encasement as they cross the host cell. The encasement fuses with the wall on both sides of the host cell, and points of entry and exit have the same appearance. Hyphae traversing host cells resemble infection threads of nodule bacteria. None of these fungi form haustoria. Prior to sporulation masses of hyphae develop in cavities produced by differential growth of host tissues or by disintegration of host cells. Hyphae in such extracellular masses are designated “lacunal hyphae.”

Studies on the haustorium of Castilleja (Scrophulariaceae). II. The endophyte

1973 ◽  
Vol 51 (5) ◽  
pp. 923-931 ◽  
Author(s):  
David R. Dobbins ◽  
Job Kuijt
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Light Microscope ◽  
Cell Walls ◽  
Host Cells ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cell Wall ◽  
Dark Staining ◽  
Host Tissues

The portion of the Castilleja haustorium within the host, the endophyte, was examined at the light-and electron-microscopic levels. The endophyte consists of a stalk of lipid-containing cells and digitate cells at its tip. Vessels run the length of the endophyte. There is a harmonious meshing between host cortical cells and those of the endophyte flank, suggesting that penetration is accomplished, in part, by cell dissolution. Crushing of cells also occurs during endophyte invasion as host phloem tissues are severely buckled and cell walls are greatly folded. Some features of digitate cells include dense cytoplasm, an abundance of endoplasmic reticulum, lateral walls that are thickened as well as those on the side adjacent to the host, and an ability to conform to the contours of host tissues. Often digitate cells are divided by very thin walls that are hardly visible under the light microscope. It is suggested that the thick cell walls may function as "free space" in the absorption of materials from the host. Within the endophyte, vessels differentiate and may contain either a finely granular, dark-staining material or a more coarsely granular, light-staining material. The particles of the latter have irregular shapes. Although granular materials are thus carried by some vessels, cells resembling the structurally intermediate "phloeotracheids" were not seen. Connections through the cell wall were not observed between parasite and host; however, within the endophyte plasmodesmata were highly branched and often contained median nodules. Transfer-like cells which have irregularly thickened walls occurred in the endophyte. Host tissues next to digitate cells appeared to be in a degraded state. Invaginations of the plasmalemma were common and small flattened vesicles were formed in some host cells from the disrupted tonoplast. In several instances, the cytoplasm had receded from the host cell wall and a "beaded" material was present in both vacuoles and large vesicles. The host cell wall at times had a very loose fibrillar appearance. Some host tracheids were occluded with a dense and dark-staining material. The xylem strands of the parasite are connected to the host xylem either by cell wall dissolution or by actual penetration of a digitate cell into a host xylary cell. The penetrating cell subsequently differentiates into a vessel member. A summary and general discussion are given to relate the two portions of the haustorium, the upper haustorium and the endophyte. The mass of new information gained in this study leads us to encourage the application of plastic embedding and sectioning techniques to further light-microscope studies on haustoria.

Comparative study of the holdfast structure in four Trichomycetes

1980 ◽  
Vol 58 (9) ◽  
pp. 1074-1087 ◽  
Author(s):  
Si-nan Dang Mayfield ◽  
Robert W. Lichtwardt
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Comparative Study ◽  
Basal Cell ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Outermost Layer ◽  
Fibrous Matrix ◽  
Ring Complex ◽  
Parallel Channels

An electron microscope study reveals considerable variation in the holdfast structure by which the fungal thalli of Trichomycetes attach to the gut lining of their arthropod hosts. Enterobryus attenuatus (Eccrinaceae) has a compound holdfast system where the holdfast substance is secreted through a reticulate ring complex located at the base of each individual thallus. The ring complex is rich in polysaccharides, as is the outermost layer of the cell wall. Enterobryus elegans produces large, single holdfasts with a fibrous matrix containing numerous parallel channels, some of which open to the gut lumen. Genistellospora homothallica (Legeriomycetaceae) has a dense and homogeneous biconcave holdfast, whereas Pennella angustispora, belonging to the same family and found in the same host, secretes an amorphous cementing substance throughout the length of the basal cell wall.

Ultrastructure of Plant Leaf Tissue Infected with Mite-Borne Viral-Like Pathogens

1970 ◽  
Vol 28 ◽  
pp. 178-179 ◽  
Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault
Keyword(s):  
Triticum Aestivum ◽  
Zea Mays ◽  
Electron Microscope ◽  
Hordeum Vulgare ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Leaf Tissue ◽  
Leaf Ultrastructure ◽  
Double Membrane ◽  
Aceria Tulipae

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).

Electron microscope study of the microgranules in human vaginal epithelium

1978 ◽  
Vol 36 (2) ◽  
pp. 568-569
Author(s):  
A. Campos ◽  
J. Vilches ◽  
J. Gomez
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Intercellular Space ◽  
Electron Microscope Study ◽  
Vaginal Epithelium ◽  
Vaginal Mucosa ◽  
Secretory Phase ◽  
Cervical Epithelium ◽  
Keratinized Epithelium ◽  
Fertile Women

Microgranules have been described with different names in keratinized and in nonkeratinized epithelium. In keratinized epithelium it seems clear that the microgranules are lamellated bodies bounded by a membrane which empty their contents into the intercellular space. Their existence in nonkeratinized epithelium is more debatable. Until now the so-called microgranules have been described in nonkeratinized bucal, lingual and cervical epithelium. In the present work we describe the morphology and nature of such structures in human vaginal epithelium.Biopsies from the midlevel of the vaginal mucosa were taken from voluntary fertile women. The specimens were divided into three groups with four vaginal specimens. The first group was obtained in the folicular phase; those of the second in the postovulatory phase and, finally, the last group corresponded to the secretory phase.

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