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.”

Ascophyllum and its symbionts. X. Ultrastructure of the interaction between A. nodosum (Phaeophyceae) and Mycophycias ascophylli (Ascomycetes)

Botany ◽  
2008 ◽  
Vol 86 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Haixin Xu ◽  
Ron J. Deckert ◽  
David J. Garbary
Keyword(s):  
Host Cell ◽  
Cortical Cell ◽  
Freeze Substitution ◽  
Host Cells ◽  
Cell Wall Modification ◽  
Transmission Electron ◽  
Host Cell Wall ◽  
Vacuolated Cells ◽  
Cell Preservation

The symbiosis of a brown alga, Ascophyllum nodosum (L.) Le Jolis and its obligate fungal symbiont, Mycophycias ascophylli (Cotton) Kohlmeyer and Volkmann-Kohlmeyer, was studied using transmission electron microscopy. A high quality of cell preservation was achieved after propane-freezing and freeze substitution; this allowed us to observe the interaction of the symbiosis without extensive artifacts. The fungus was found in the middle portion of cortical-cell walls, and at the edge of medullary cells and air-bladder filaments, but never close to host cell protoplasm. Host cell-wall modification was limited to a short distance around the hyphae. A sheath with electron-dense materials around the fungus was found in the older hyphae, but not in the hyphal tips. A range of hyphal ultrastructure was observed from cells with dense cytoplasm, absent to slight vacuolation and with well-defined organelles, to highly vacuolated cells with little cytoplasm and poorly defined organelles, to senescent cells that were often collapsed with no recognizable organelles. No sign of typical cytological resistance responses was observed in host cells, thus confirming the nonantagonistic nature of the two symbionts.

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.

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.

Ultrastructure of compatible and incompatible reactions of sunflower to Plasmopara halstedii

1979 ◽  
Vol 57 (4) ◽  
pp. 315-323 ◽  
Author(s):  
Glenn Wehtje ◽  
Larry J. Littlefield ◽  
David E. Zimmer
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Host Cell ◽  
Epidermal Cell ◽  
Cortical Cell ◽  
Hypersensitive Reaction ◽  
Host Cells ◽  
Plasmopara Halstedii ◽  
Host Cell Wall ◽  
Host Plasma Membrane

Penetration of sunflower, Heliantluis animus, root epidermal cells by zoospores of Plasmopara halstedii is preceded by formation of a papilla on the inner surface of the host cell wall that invaginates the host plasma membrane. Localized degradation and penetration of the host cell wall by the pathogen follow. The invading fungus forms an allantoid primary infection vesicle in the penetrated epidermal cell. The host plasma membrane invaginates around the infection vesicle but its continuity is difficult to follow. Upon exit from the epidermal cell the fungus may grow intercellularly, producing terminal haustorial branches which extend into adjacent host cells. The fungus may grow through one or two cortical cell is after growing from the epidermal cell before it becomes intercellular. Host plasma membrane is not penetrated by haustoria. Intercellular hyphae grow toward the apex of the plant and ramify the seedling tissue. Resistance in an immune cultivar is hypersensitive and is triggered upon contact of the host cell with the encysting zoospore before the host cell wall is penetrated. Degeneration of zoospore cytoplasm accompanies the hypersensitive reaction of the host. Zoospores were often parasitized by bacteria and did not germinate unless penicillin and streptomycin were added to the inoculum suspension.

Structure and host–actinomycete interactions in developing root nodules of Comptonia peregrina

1978 ◽  
Vol 56 (5) ◽  
pp. 502-531 ◽  
Author(s):  
William Newcomb ◽  
R. L. Peterson ◽  
Dale Callaham ◽  
John G. Torrey
Keyword(s):  
Host Cell ◽  
Root Nodules ◽  
Host Cells ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cytoplasm ◽  
Transmission Electron ◽  
Microscopic Studies ◽  
Host Plasma Membrane ◽  
Soil Actinomycete

Correlated fluorescence, bright-field, transmission electron, and scanning electron microscopic studies were made on developing root nodules of Comptonia peregrina (L.) Coult. (Myricaceae) produced by a soil actinomycete which invades the root and establishes a symbiosis leading to fixation of atmospheric dinitrogen. After entering the host via a root hair infection, the hyphae of the endophyte perforate root cortical cells by local degradation of host cell walls and penetration of the host cytoplasm. The intracellular hyphae are always surrounded by host plasma membrane and a thick polysaccharide material termed the capsule. (For convenience, term intracellular refers to the endophyte being inside a Comptonia cell as distinguished from being intercellular, i.e.. between host cells, even though the former is actually extracellular as the endophyte is separated from the host cytoplasm by the host plasmalemma.) Numerous profiles of vesiculate rough endoplasmic reticulum (RER) occur near the growing hyphae. Although the capsule shows a positive Thiery reaction indicating its polysaccharide nature, the fibrillar contents of the RER do not, leaving uncertain whether the capsule results from polymers derived from the RER. Amyloplasts of the cortical cells lose their starch deposits during hyphal proliferation. The hyphae branch extensively in specific layers of the cortex, penetrating much of the host cytoplasm. At this stage, hyphal ends become swollen and form septate club-shaped vesicles within the periphery of the host cells. Lipid-like inclusions and Thiery-positive particles, possibly glycogen, are observed in the hyphae at this time. Associated with hyphal development is an increase in average host cell volume, although nuclear volume appears to remain constant. Concomitant with vesicle maturation, the mitochondrial population increases sharply, suggesting a possible relationship to vesicle function. The intimate interactions between host and endophyte during development of the symbiotic relationship are emphasized throughout.

Histopathology of Fusarium wilt of staghorn sumac (Rhus typhina) caused by Fusarium oxysporum f. sp. callistephi race 3. III. Host cell and tissue reactions

2006 ◽  
Vol 87 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Guillemond B. Ouellette ◽  
Mohamed Cherif ◽  
Marie Simard
Keyword(s):  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Host Cell ◽  
Cross Wall ◽  
Tissue Proliferation ◽  
Host Cytoplasm ◽  
Transmission Electron ◽  
Host Cell Wall ◽  
Tissue Reactions ◽  
Rhus Typhina

Abstract Various cell reactions occurred in staghorn sumac plants inoculated with Fusarium oxysporum f. sp. callistephi. Light and transmission electron microscopy observations and results of cytochemical tests showed: 1) increased laticifers and latex production in the phloem; 2) tylosis formation; 3) host cell wall modifications, including appositions or other cell wall thickenings; and 4) unusual cross wall formation in some cells, and cell hypertrophy and hyperplasia. Tylosis walls labelled for pectin and cellulose and many displayed inner suberin-like layers. These layers were also noted in cells of the medullary sheath and in many cells with dense content and thickened walls in the barrier zones that had formed. These zones also contained fibres with newly-formed gelatinous-like layers. In the vicinity of these cells, host cell walls were frequently altered, associated with opaque matter. Many small particles present in chains also occurred in some of these cells, which contained only remnants of host cytoplasm. Light microscopy observations showed that pronounced tissue proliferation and aberrant cells occurred in the outer xylem in the infected plants. Unusual neoplasmic tissue also formed from cells surrounding the pith and medullary sheath, and it spanned directly across the pre-existing xylem tissue and burst as large mounds on the stems.

scholarly journals Evidence for Antibiosis and Induced Host Defense Reactions in the Interaction Between Verticillium lecanii and Penicillium digitatum, the Causal Agent of Green Mold

2000 ◽  
Vol 90 (9) ◽  
pp. 932-943 ◽  
Author(s):  
Nicole Benhamou ◽  
Jacques Brodeur
Keyword(s):  
Plasma Membrane ◽  
Host Cell ◽  
De Novo ◽  
Penicillium Digitatum ◽  
Verticillium Lecanii ◽  
Intercellular Interaction ◽  
Green Mold ◽  
Transmission Electron ◽  
Host Cell Wall ◽  
Host Cell Surface

Chronological events of the intercellular interaction between Verticillium lecanii and the postharvest pathogen Penicillium digitatum were investigated by transmission electron microscopy and gold cytochemistry. Growth inhibition of P. oligandrum as a response to V. lecanii attack correlated with striking host changes including retraction of the plasma membrane and cytoplasm disorganization. Such changes were associated with the deposition on the inner host cell surface of a chitin- and cellulose-enriched material which appeared to be laid down as a structural defense reaction. The accumulation of chitin in the newly formed material correlated with a decrease in the amount of wallbound chitin. However, the deposition of cellulose appeared to correspond to a de novo synthesis, as evidenced by the occurrence of cellulose-containing vesicles which released their content in the space between the invaginated plasma membrane and the host cell wall. Results of the present study provide the first ultrastructural and cytochemical evidence that antagonism, triggered by V. lecanii, is a multifaceted process in which antibiosis, with alteration of the host hyphae prior to contact with the antagonist, appears to be the key process in the antagonism against P. digitatum.

scholarly journals Defining the Mechanical Determinants of Kingella kingae Adherence to Host Cells

2017 ◽  
Vol 199 (23) ◽  
Author(s):  
Brad K. Kern ◽  
Eric A. Porsch ◽  
Joseph W. St. Geme
Keyword(s):  
Host Cell ◽  
High Strength ◽  
Type Iv Pili ◽  
Host Cells ◽  
Initial Contact ◽  
Kingella Kingae ◽  
Content Type ◽  
Type Iv ◽  
Transmission Electron ◽  
Trimeric Autotransporter Adhesin

ABSTRACT Kingella kingae is an important pathogen in young children and initiates infection by colonizing the posterior pharynx. Adherence to pharyngeal epithelial cells is an important first step in the process of colonization. In the present study, we sought to elucidate the interplay of type IV pili (T4P), a trimeric autotransporter adhesin called Knh, and the polysaccharide capsule in K. kingae adherence to host cells. Using adherence assays performed under shear stress, we observed that a strain expressing only Knh was capable of higher levels of adherence than a strain expressing only T4P. Using atomic force microscopy and transmission electron microscopy (TEM), we established that the capsule had a mean depth of 700 nm and that Knh was approximately 110 nm long. Using cationic ferritin capsule staining and thin-section transmission electron microscopy, we found that when bacteria expressing retractile T4P were in close contact with host cells, the capsule was absent at the point of contact between the bacterium and the host cell membrane. In a T4P retraction-deficient mutant, the capsule depth remained intact and adherence levels were markedly reduced. These results support the following model: T4P make initial contact with the host cell and mediate low-strength adherence. T4P retract, pulling the organism closer to the host cell and displacing the capsule, allowing Knh to be exposed and mediate high-strength, tight adherence to the host cell surface. This report provides the first description of the mechanical displacement of capsule enabling intimate bacterial adherence to host cells. IMPORTANCE Adherence to host cells is an important first step in bacterial colonization and pathogenicity. Kingella kingae has three surface factors that are involved in adherence: type IV pili (T4P), a trimeric autotransporter adhesin called Knh, and a polysaccharide capsule. Our results suggest that T4P mediate initial contact and low-strength adherence to host cells. T4P retraction draws the bacterium closer to the host cell and causes the displacement of capsule. This displacement exposes Knh and allows Knh to mediate high-strength adherence to the host cell. This work provides new insight into the interplay of T4P, a nonpilus adhesin, and a capsule and their effects on bacterial adherence to host cells.

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 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.

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