Sporidial mating and infection process of the smut fungus, Ustilago hordei, in susceptible barley

2002 ◽  
Vol 80 (10) ◽  
pp. 1103-1114 ◽  
Author(s):  
G G Hu ◽  
R Linning ◽  
G Bakkeren
Keyword(s):  
Plasma Membranes ◽  
Unknown Origin ◽  
Infection Process ◽  
Dense Matrix ◽  
Transmission Electron ◽  
Polar Conjugation ◽  
Ustilago Hordei ◽  
Germinated Barley ◽  
Electron Dense Matrix ◽  
Plant Plasma Membrane

Ustilago hordei (Pers.) Lagerh. causes covered smut of barley and oats. Sporidial mating and the infection process on compatible barley plants, cv. Hannchen, were investigated using light microscopy and scanning and transmission electron microscopy. Within 2 h after mixing of sporidia of opposite mating types on water agar, polar conjugation tubes emerged that subsequently fused, producing infection hyphae at the junctions. Similar events occurred on germinated barley shoots, although sporidia regularly produced several conjugation tubes, of which only one was involved in mating. Tubes emerging from the sides of cells were also observed. Infection hyphae emerged from either the conjugation tube or conjugated cell body. Hyphae elongated along the shoot surface until characteristic crook and appressorium-like structures were formed. An invading hypha emerged beneath this structure and directly penetrated the underlying epidermal cell. Hyphae extended both intra- and inter-cellularly into tissues, without much branching, before becoming established in the shoot meristematic region. Plant plasma membranes remained intact during pathogen ingress and an electron-dense matrix of unknown origin appeared in the interface between plant plasma membrane and invading hypha. A large fungal biomass was generated in the host spike tissue at 42–63 days postinoculation during the development of the floral meristem.Key words: Hordeum vulgare, pathogen, sporidia, teliospores, ultrastructure, Ustilaginales.

Fine structure of the anterior adhesive apparatus (head organs) of Bravohollisia gussevi Lim, 1995 (Monogenea: Ancyrocephalidae)

Parasitology ◽  
2005 ◽  
Vol 132 (3) ◽  
pp. 427-438 ◽  
Author(s):  
W. L. WONG ◽  
G. P. BRENNAN ◽  
D. W. HALTON ◽  
L. H. S. LIM
Keyword(s):  
Electron Microscopy ◽  
Gland Cell ◽  
Light And Electron Microscopy ◽  
Dense Matrix ◽  
General Body ◽  
Gland Cells ◽  
Transmission Electron ◽  
Similar Band ◽  
Electron Dense Matrix ◽  
Dense Vesicles

A study of the anterior adhesive apparatus (head organs) of Bravohollisia gussevi Lim, 1995 was carried out using light and electron microscopy. The anterior adhesive apparatus or head organs in B. gussevi comprise 6 circular openings or apertures in the antero-lateral region, associated pits lined with specialized microvillous tegument that differ from the general body tegument, a bundle of ducts, and uninucleate gland cells located lateral to the pharynx. The uninucleate glands of the anterior adhesive apparatus (head organs) comprise 2 types of cells, one kind of cell producing rod-like bodies (S1) and the other oval bodies (S2). The S1 bodies are filled with numerous, less electron-dense vesicles in an electron-dense matrix, while S2 bodies have no vesicles but contain a more homogeneous electron-dense matrix. Interlinking band-like structures were observed between S1 bodies. Similar band-like structures were found between S2 bodies. The formation of S1 bodies was followed by transmission electron microscopy. However, the formation of S2 bodies was unclear and could not be resolved. Uniciliated structures were also observed around the openings of the anterior adhesive apparatus. Each uniciliated structure is usually associated with an opening of a gland cell producing granular, electron-dense, secretory bodies, which differ from the secretions produced by the lateral gland cells of the anterior adhesive apparatus.

scholarly journals Unusual Psammoma Bodies in an Extracranial Syncytial Meningioma from a Dog

1980 ◽  
Vol 17 (1) ◽  
pp. 45-52 ◽  
Author(s):  
J. A. Fagerland ◽  
J. H. Greve
Keyword(s):  
Light Microscopy ◽  
Plasma Membranes ◽  
Cervical Vertebra ◽  
Dense Matrix ◽  
Psammoma Bodies ◽  
The Third ◽  
Cytoplasmic Vesicles ◽  
Granular Matrix ◽  
The Right ◽  
Electron Dense Matrix

An epidural neoplasm was removed from the right side of the third cervical vertebra of a Blue Tick Hound dog. By light microscopy the tumor was classified as a syncytial meningioma containing psammoma bodies that were histochemically positive for calcium salts, but negative for reticulum fibers and collagen. Ultrastructurally, the tumor cells had numerous processes and desmosomes. Cytoplasmic fibrils were sparse. Coated cytoplasmic vesicles frequently were fused with plasma membranes. The psammoma bodies were not within the cytoplasm, but were in spaces continous with the extracellular space. The bodies were composed of a medium electron-dense matrix; a crystalline, highly electron-dense center; and, sometimes, short fibrils embedded in the granular matrix.

Ultrastructural characteristics of sporidia of Ustilago

1989 ◽  
Vol 47 ◽  
pp. 786-787
Author(s):  
Patricia N. Hackney
Keyword(s):  
Electron Microscope ◽  
Type System ◽  
Tube Formation ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
University Of Wisconsin ◽  
Transmission Electron ◽  
Ustilago Hordei ◽  
Silene Alba ◽  
The University

Ustilago hordei and Ustilago violacea are yeast-like basidiomycete pathogens ofHordeum vulgare and Silene alba respectively. The mating type system in both species of Ustilago is bipolar, with alleles, A,a, (U.hordei) and a1, a2 (U.violacea) at a single locus. Haploid sporidia maintain the asexual phase by budding, while the sexual phase is initiated by conjugation tube formation between the mating types during budding and conjugation.For observation of budding, sporidia were prepared by culturing the four types on YEG (yeast extract glucose) broth for 24 hours. After centrifugation at 5000g cells were either left unmated or mated in a1/a2,A/a combinations. The sporidia were then mixed 1:1 with 4% agar and the resulting 1mm cubes fixed in 8% gluteraldehyde and post fixed in osmium tetroxide. After dehydration and embedding cubes were thin sectioned with a LKB ultratome and photographed in a Zeiss 9s transmission electron microscope or in an AE1 electron microscope of MK11 1MEV at the High Voltage Electron Microscopy Center of the University of Wisconsin-Madison.

Liver ultrastructure in sheep fasciolosis

2021 ◽  
Vol 1 (1) ◽  
pp. 6-12
Author(s):  
V. N. Baymatov ◽  
◽  
G. R. Shakirova ◽  
Keyword(s):  
Experimental Infection ◽  
Ultrastructural Level ◽  
Dense Matrix ◽  
Membrane Structures ◽  
Liver Ultrastructure ◽  
Perinuclear Space ◽  
Liver Membrane ◽  
Electron Dense Matrix ◽  
Anthelmintic Drugs

This experiment has studied the changes in the liver in sheep during experimental infection with fascioliasis. Sheep were infested with 300 adoliskaria and observed changes up to 142 days. At the ultrastructural level in animals with fascioliasis, destructive changes were found in the liver. In the nucleus, the number of nucleoli decreases or they disappear completely, fragmentation of heterochromatin occurs and the content of euchromatin increases. The karyolemma exfoliates from the nucleus, as a result of which the perinuclear space expands. Mitochondria swell, they are polymorphic, and have an electron-dense matrix. At the beginning of the invasion, their number increases, and then their vacuolization, destruction occurs, while under the action of anthelmintic drugs and fasciolus toxins, the structure of the endolasmic network first of all changes: its cavities expand, then fragmentation occurs. Ribosomes are sprayed into the cytoplasm of the hepatocyte. It should be noted that under the influence of hexichol, acemidophene and thiopagol in the liver, membrane structures change most significantly and undergo necrobiosis.

scholarly journals Fertilization in the cestode Echinococcus multilocularis (Cyclophyllidea, Taeniidae)

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Zdzisław Świderski ◽  
Jordi Miquel ◽  
Samira Azzouz-Maache ◽  
Anne-Françoise Pétavy
Keyword(s):  
Echinococcus Multilocularis ◽  
Plasma Membranes ◽  
Cell Types ◽  
Sperm Nucleus ◽  
Cortical Granules ◽  
Transmission Electron ◽  
Perinuclear Cytoplasm ◽  
Female Pronucleus ◽  
Lateral Fusion ◽  
Means Of Transmission

AbstractFertilization in the taeniid cestode Echinococcus multilocularis with uniflagellate spermatozoa was examined by means of transmission electron microscopy (TEM). Fertilization in this species occurs in the oviduct lumen or in the fertilization canal proximal to the ootype, where the formation of the embryonic capsule precludes sperm contact with the oocytes. Cortical granules are not present in the cytoplasm of the oocytes of this species, however, several large bodies containing granular material where frequently observed. Spermatozoa coil spirally around the oocytes and syngamy occurs by lateral fusion of oocyte and sperm plasma membranes. In the ootype, one vitellocyte associates with fertilized oocyte, forming a membranous capsule which encloses both cell types. In this stage, the spirally coiled sperm body adheres partly to the external oocyte surface, and partially enters into the perinuclear cytoplasm. The electron-dense sperm nucleus becomes progressively electron-lucent within the oocyte cytoplasm after penetration. Simultaneously with chromatin decondensation, the elongated sperm pronucleus changes shape, forming a spherical male pronucleus, which attains the size of the female pronucleus. Cleavage begins immediately after pronuclear fusion.

An ultrastructural study of pollen development in tomato (Lycopersicon esculentum). I. Tetrad to early binucleate microspore stage

1993 ◽  
Vol 71 (8) ◽  
pp. 1039-1047 ◽  
Author(s):  
P. L. Polowick ◽  
V. K. Sawhney
Keyword(s):  
Endoplasmic Reticulum ◽  
Lycopersicon Esculentum ◽  
Ultrastructural Study ◽  
Pollen Development ◽  
Pollen Wall ◽  
Ultrastructural Changes ◽  
Dense Matrix ◽  
Tetrad Stage ◽  
Microspore Stage ◽  
Electron Dense Matrix

Microspores undergo considerable ultrastructural changes between the tetrad and early binucleate microspore stages of microsporogenesis in tomato (Lycopersicon esculentum). Pollen wall deposition began late in the tetrad stage, and by the early microspore stage a lamellar foot layer and tectum were deposited. Sculpturing of the tectum was evident by the early binucleate microspore stage. Dictyosomes and vesicles were abundant during the period of pollen wall formation. Plastids were associated with the endoplasmic reticulum (ER) to form plastid–ER complexes, from the late tetrad to the vacuolate microspore stage. At the vacuolate microspore stage, endoplasmic reticulum independent of plastids was also observed, and at the early binucleate microspore stage ER was not associated with plastids. Free ribosomes were evenly distributed throughout the cytoplasm until the vacuolate microspore stage when they were organized into polysomes. Mitochondria were spherical to ellipsoid, with an electron-dense matrix and swollen cristae, until the early binucleate microspore stage when they were highly elongate and became convoluted. Key words: Lycopersicon esculentum, microsporogenesis, pollen development, tetrads, tomato, ultrastructure.

scholarly journals IDENTIFICATION OF PEROXISOMES IN THE RAT ADRENAL CORTEX

1972 ◽  
Vol 20 (3) ◽  
pp. 173-179 ◽  
Author(s):  
MARGARET E. BEARD
Keyword(s):  
Acid Phosphatase ◽  
Adrenal Cortex ◽  
Zona Fasciculata ◽  
Positive Staining ◽  
Staining Reaction ◽  
Dense Matrix ◽  
Zona Reticularis ◽  
Liver And Kidney ◽  
Branched Structures ◽  
Electron Dense Matrix

Organelles with the ultrastructure and cytochemical characteristics of peroxisomes (microbodies) have been identified in cells of the zona fasciculata and zona reticularis of the rat adrenal cortex. These peroxisomes appear as small, elliptical to spherical or branched structures, enclosed by a single membrane and composed of a moderately electron-dense matrix. They do not possess a nucleoid or core of the type found in peroxisomes of liver and kidney. These organelles show a strongly positive staining reaction with the diaminobenzidine technique for peroxidatic activity of catalase. This staining is inhibited by aminotriazole. In cytochemical preparations revealing acid phosphatase activity, lysosomes are strongly stained and peroxisomes are free of reaction product.

Ultrastructure of conidium ontogeny in Phoma pomorum, Microsphaeropsis olivaceum, and Coniothyrium fuckelii

1976 ◽  
Vol 54 (9) ◽  
pp. 831-851 ◽  
Author(s):  
John P. Jones
Keyword(s):  
Electron Microscopy ◽  
Dense Matrix ◽  
Spore Dispersal ◽  
Electron Dense Matrix

The techniques of electron microscopy have been used to elucidate the details of conidium ontogeny in Phoma pomorum, Microsphaeropsis olivaceum, and Coniothyrium fuckelii. All three of these organisms were shown to be phialidic. The pyenidia of these organisms contained an electron-dense matrix, which in nature, probably functions as an aid to spore dispersal. In Phoma pomorum it was possible to trace conidia to their originating conidiophore through this matrix.

Teliospore wall structure in Entorrhiza (Tilletiaceae) and its relationship to taxonomy of the genus

1992 ◽  
Vol 70 (10) ◽  
pp. 1964-1983 ◽  
Author(s):  
Brian A. Fineran ◽  
Judith M. Fineran
Keyword(s):  
Electron Microscopy ◽  
Outer Zone ◽  
Spore Wall ◽  
Wall Structure ◽  
Dense Matrix ◽  
Thin Sections ◽  
Transmission Electron ◽  
Layer 2 ◽  
Layer 4 ◽  
Freeze Etching

Spore wall organization in the five species of Entorrhiza (Ustilaginales) has been investigated using thin sections for transmission electron microscopy, supported by light and scanning electron microscopy and some freeze-etching. Material was examined from herbaria, specimens preserved in fixative, and fresh host tissue. The wall has four main layers, numbered 1–4 from the outside to inside of the wall; some layers are further differentiated into zones. Layer 1 in E. aschersoniana, E. caspaiyana, and E. caricicola has two zones: a broad outer zone 2 of dense matrix and a narrow inner zone 1 of less compacted material. Zone 1 is absent in E. cypericola. In E. scirpicola, layer 1 is represented by discontinuous longitudinal ridges. In all spores, layer 2 is composed of a homogeneous electron-dense matrix. Layer 1 in E. aschersoniana, E. casparyana, and E. caricicola is uniformly thick, but in E. cypericola it is broad with an irregular outer margin. In E. scirpicola, layer 2 is differentiated into a distinctive pattern of longitudinal ribs. In all spores of Entorrhiza, layer 3 is resolvable into fine lamellae, corresponding to the mosaic of striations seen after freeze-etching. Layer 3 in Entorrhiza is equivalent to the partition layer described in other Tilletiaceae. Layer 4 has the same organization in all the species, consisting of a very narrow zone 2 abutting layer 3 and a broad zone 1 that forms the rest of the layer. Based on wall structure, E. aschersoniana and E. casparyana represent the most closely related species, followed by E. caricicola, with E. cypericola more distant again. Entorrhiza scirpicola is considered the least related of the species; only its layers 3 and 4 resemble the other species. Key words: Entorrhiza, Tilletiaceae, spore wall ultrastructure, species relationships.

scholarly journals PEROXISOMES IN DORSAL ROOT GANGLIA

1973 ◽  
Vol 21 (1) ◽  
pp. 34-41 ◽  
Author(s):  
ELENA CITKOWITZ ◽  
ERIC HOLTZMAN
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Schwann Cells ◽  
Dorsal Root Ganglia ◽  
Acid Phosphatase Activity ◽  
Dorsal Root ◽  
Dense Matrix ◽  
Crystalline Core ◽  
Electron Dense Matrix

Bodies with the morphologic and cytochemical characteristics of peroxisomes have been identified in the satellite and Schwann cells of rat dorsal root ganglia. They are membrane-delimited, round or oval structures which contain a moderately electron-dense matrix but lack a crystalline core. On incubation of the tissue in a cytochemical medium for demonstration of peroxisomes, these bodies show heavy deposits of reaction product. The reaction is inhibited by heating the tissue or by incubation in the presence of aminotriazole or dichlorophenolindophenol. In tissue incubated for acid phosphatase activity the bodies are not reactive, although lysosomes show reaction product.

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