Ultrastructural karyology of Spongospora subterranea (Plasmodiophoromycetes)

1992 ◽  
Vol 70 (6) ◽  
pp. 1228-1233 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Electron Microscopy ◽  
Single Unit ◽  
Spongospora Subterranea ◽  
Unit Membrane ◽  
Potato Tubers ◽  
Haploid Chromosome Number ◽  
Synaptonemal Complexes ◽  
Transmission Electron ◽  
Host Parasite ◽  
Section Analysis

Sporogenic (cystogenous) stages of development of Spongospora subterranea (Wallroth) Lagerheim f.sp. subterranea Tomlinson infecting potato tubers were examined with transmission electron microscopy. Volume of nuclei in transitional Plasmodia was 28.2 ± 8.3 μm3. Serial section analysis revealed 37 synaptonemal complexes, hence the haploid chromosome number was considered to be 37. Total length of synaptonemal complexes per nucleus was 74.6 ± 1.4 μm, with individual synaptonemal complexes ranging in length from 1.34 ± 0.07 μm to 3.48 ± 0.17 μm. No polycomplexes were observed in transitional nuclei. Electron-opaque thickenings of lateral elements occurred irregularly. Additional ultrastructural features of sporogenic plasmodia included end-to-end paired centrioles defining the poles of the nuclei and a host–parasite boundary of a single unit membrane. Key words: karyotype, Plasmodiophoromycetes, Spongospora, synaptonemal complex.

The Plasmodiophoromycete parasitic on Heteranthera dubia

1983 ◽  
Vol 61 (1) ◽  
pp. 45-52 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Unit ◽  
Host Cells ◽  
Synaptonemal Complexes ◽  
Transmission Electron ◽  
Resting Spores ◽  
End To End ◽  
Host Parasite

Light and transmission electron microscopy were used to characterize representative stages of sporogenic plasmodia and resting spores of the plasmodiophorid parasite in roots of Heteranthera dubia (Jacq.) MacM. (water-stargrass). Cruciform nuclear divisions occurred in young plasmodia and noncruciform divisions occurred in more mature, transitional plasmodia. Prophase nuclei in transitional plasmodia contained synaptonemal complexes; noncruciform divisions were interpreted, therefore, as meiosis. Host–parasite interfaces were single unit membranes. Centrioles were paired end-to-end in plasmodia, but unpaired, single centrioles were in resting spores. Resting spores also contained crystalline bodies. Sporosori were disklike, consisted predominantly of single layers of resting spores, and were located at the periphery of host cells. Membranosorus heterantherae Ostenfeld and Peterson was considered the appropriate genus–species for the parasite, not Sorodiscus heterantherae Wernham.

Ultrastructure and karyology of Tetramyxa parasitica (Plasmodiophoromycetes)

1990 ◽  
Vol 68 (3) ◽  
pp. 594-598 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Single Unit ◽  
Nuclear Division ◽  
Ruppia Maritima ◽  
Serial Sections ◽  
Unit Membrane ◽  
Haploid Chromosome Number ◽  
Resting Spores ◽  
Host Parasite

Tetramyxa parasitica Goebel was located in galls on shoots of Ruppia maritima L. var. maritima and Zannichellia palustris L. subsp. repens (Boenn.) Schübler & Martens. Ultrastructural features of sporogenic (cystogenous) development included a host–parasite boundary of a single unit membrane, cruciform nuclear division in young plasmodia, synaptomenal complexes in nuclei of transitional plasmodia, and resting spores grouped in fours. Synaptonemal complexes in nuclei were counted through analysis of serial sections. The haploid chromosome number was determined to be 32, which distinguished Tetramyxa from other plasmodiophorid genera. Key words: karyotype, Tetramyxa, Plasmodiophoromycetes.

Wilts caused by Verticillium species. A cytological survey of vascular alterations in leaves

1982 ◽  
Vol 60 (6) ◽  
pp. 825-837 ◽  
Author(s):  
Jane Robb ◽  
Alexandra Smith ◽  
Lloyd Busch
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Sem Analysis ◽  
Disease Symptoms ◽  
Vascular Tissues ◽  
Transmission Electron ◽  
Tem Method ◽  
Cytological Alterations ◽  
Host Parasite ◽  
Leaf Symptoms

Plants that are infected with fungi of the species Verticillium frequently develop foliar disease symptoms which may include one or more of the following: flaccidity, drying, chlorosis leading to necrosis, vascular browning, epinasty, and leaf abscission. A number of ultrastructural and chemical alterations occur in the vascular tissues of such leaves: deposition of brown pigments, coating of xylem vessel walls with abnormal material (i.e., lipid-rich coatings or fibrillar coatings), plugging of xylem vessels with gums, gels or tyloses, degeneration of parenchyma cells, and accumulation of abnormal electron dense materials in primary and secondary cell walls. Different host–parasite combinations exhibit different leaf symptoms and different cytological alterations. The purpose of the present survey was to determine whether the extent of any of the possible vascular alterations in leaves could be correlated with the wilting tendency of the host.Chrysanthemums, snapdragons, eggplants, sunflowers, potatoes, sycamore maples and hedge maples were infected with V. dahliae; alfalfa and hops were infected with V. albo-atrum. When leaf symptoms were well advanced, samples were taken from the major lateral leaf veins and were prepared for light (LM) and transmission electron microscopy (TEM) or scanning electron microscopy (SEM). The various types of alterations in the vascular tissues were identified by a correlated LM–TEM method and (or) SEM analysis and for each sample vein the proportion of vessels affected by each type of alteration was calculated. Four leaf samples, each from different plants, were analysed for each host. The visual symptoms, including vascular browning, were estimated subjectively. The degree of leaf flaccidity was correlated positively with the proportion of lipid-coated vessels and inversely with the degree of vascular browning. No other correlations were observed.

Bacteriocin-like substance inhibits potato soft rot caused by Erwinia carotovora

2006 ◽  
Vol 52 (6) ◽  
pp. 533-539 ◽  
Author(s):  
Florencia Cladera-Olivera ◽  
Geruza R Caron ◽  
Amanda S Motta ◽  
André A Souto ◽  
Adriano Brandelli
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bacillus Licheniformis ◽  
Membrane Lipids ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Bactericidal Effect ◽  
Potato Tubers ◽  
Transmission Electron ◽  
Bacterial Surfaces

Soft rot is a major problem encountered in potatoes during postharvest storage. The soft rot bacterium Erwinia carotovora was inhibited by a novel bacteriocin-like substance (BLS) produced by Bacillus licheniformis P40. The BLS caused a bactericidal effect on E. carotovora cells at 30 µg mL–1. Transmission electron microscopy showed that BLS-treated cells presented wrinkled bacterial surfaces and shrinkage of the whole cell, indicating plasmolysis. Erwinia carotovora cells treated with BLS were analyzed by FTIR showing differences in the 1390 cm–1 and 1250–1220 cm–1 bands, corresponding to assignments of membrane lipids. BLS was effective in preventing E. carotovora spoilage on potato tubers, reducing the symptoms of soft rot at 240 µg mL–1 and higher concentrations. Soft rot development was completely blocked at 3.7 mg mL–1. This BLS showed potential to protect potato tubers during storage. Key words: bacteriocin, plant pathogen, potato, soft rot, storage.

Host–parasite interfaces in a resistant and a susceptible cultivar of Solanum tuberosum inoculated with Phytophthora infestans: tuber tissue

1976 ◽  
Vol 54 (9) ◽  
pp. 900-912 ◽  
Author(s):  
Hans R. Hohl ◽  
Peter Stössel
Keyword(s):  
Solanum Tuberosum ◽  
Phytophthora Infestans ◽  
Susceptible Cultivar ◽  
Potato Tubers ◽  
Tuber Tissue ◽  
Susceptible Host ◽  
Transmission Electron ◽  
Wall Appositions ◽  
Host Parasite ◽  
Extrahaustorial Matrix

Host–parasite interfaces in potato tubers (Solanum tuberosum) of a resistant (Eba) and a susceptible (Bintje) cultivar inoculated with Phytophthora infestans were studied with transmission electron microscopy. In the resistant host the fungal haustoria are typically small and surrounded by an electron-dense extrahaustorial matrix and electron-transparent wall appositions, normally in form of complete encasements. Wall appositions are generally lacking in the susceptible host or occasionally are found as a collar at the base of the rather large haustorium, which is surround by a well developed extrahaustorial matrix. Since wall appositions probably contain largely a callose-like material, potential roles of fungal glucanases in this host–parasite system are discussed.

Karyotypic analysis of Membranosorus heterantherae (Plasmodiophoromycetes)

1989 ◽  
Vol 67 (4) ◽  
pp. 1219-1220 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Chromosome Number ◽  
Serial Section ◽  
Karyotypic Analysis ◽  
Haploid Chromosome Number ◽  
Synaptonemal Complexes ◽  
Section Analysis

Synaptonemal complexes in nuclei of transitional plasmodia of Membranosorus heterantherae were counted through serial section analysis. The haploid chromosome number was determined to be 35, which distinguishes Membranosorus from other plasmodiophorid genera.

Wound healing in whole potato tubers: a cytochemical, fluorescence, and ultrastructural analysis of cut and bruise wounds

1995 ◽  
Vol 73 (9) ◽  
pp. 1436-1450 ◽  
Author(s):  
Norman Thomson ◽  
Ray F. Evert ◽  
Arthur Kelman
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Wound Healing ◽  
Healing Process ◽  
Potato Tubers ◽  
Bright Field ◽  
Wound Site ◽  
Transmission Electron ◽  
Suberin Lamellae ◽  
Wound Reaction

Healing was investigated in whole tubers wounded by cuts and bruises and compared with core, disc, and slice wounds. Bright-field, fluorescence, and transmission electron microscopy were used in conjunction with cytochemical analyses. Wound reaction cells bordering a wound site responded to wounding initially with deposition of callose at the primary pit fields followed by intussusception of lignin in the middle lamellae and primary walls and suberization along the inner surfaces of the primary walls. Suberization was initially detected by the presence of a prosuberin lamella in which suberin lamellae subsequently developed. Both lignin and the prosuberin lamella were first detected in wound reaction cells of the cortex at 4 h in cut, core, disc, and slice wounds and at 8 h in bruise wounds. Healing was completed with formation of a continuous wound cork cambium beneath the wound site. With lignification and suberization, wounded potato tubers apparently develop specialized barriers against potential pathogens and water loss. The overall healing process proceeds more slowly in bruise wounds than in cut wounds. Moreover, the capacity for wound healing decreases with increasing age of the tuber, or time in storage. Key words: lignin, prosuberin lamella, Solanum tuberosum, suberin, suberization, wound healing.

Austrostigmidium, a new austral genus of lichenicolous fungi close to rock-inhabiting meristematic fungi in Teratosphaeriaceae

2015 ◽  
Vol 47 (3) ◽  
pp. 143-156 ◽  
Author(s):  
Sergio Pérez-Ortega ◽  
Isaac Garrido-Benavent ◽  
Asunción De Los Ríos
Keyword(s):  
Electron Microscopy ◽  
New Genus ◽  
Fungal Species ◽  
Tierra Del Fuego ◽  
Lichenicolous Fungi ◽  
Transmission Electron ◽  
The Family ◽  
Meristematic Fungi ◽  
Means Of Transmission ◽  
Host Parasite

AbstractThe new genus of lichenicolous fungi Austrostigmidium is described from Antarctica and Tierra del Fuego (Chile). It is characterized by the presence of black pseudothecia, pseudoparaphyses, fissitunicate, I−, KI− asci and 3-septate hyaline ascospores. So far, the only known species grows on Mastodia tessellata (Verrucariales, Eurotiomycetes). The new genus is compared with anatomically close genera. Based on nuLSU and nuSSU markers we inferred its phylogenetic relationships and found that it belongs to the family Teratosphaeriaceae (Capnodiales, Dothideomycetes) and is closely related to rock-inhabiting fungal species, as well as to the hyphomycetous lichenicolous fungus Xanthoriicola. Finally, the host-parasite interface has been analyzed by means of transmission electron microscopy and fluorescence microscopy in order to describe the interactions among the new fungus and the symbionts forming the host lichen.

Eocronartium muscicola: a basidiomycetous moss parasite exploiting gametophytic transfer cells

1988 ◽  
Vol 66 (4) ◽  
pp. 762-770 ◽  
Author(s):  
E. W. A. Boehm ◽  
D. J. McLaughlin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transfer Cells ◽  
Transmission Electron ◽  
Host Parasite ◽  
Relationship Of ◽  
The Relationship ◽  
Gain Access ◽  
Scanning Electron

The host–parasite interface in Eocronartium muscicola, Auriculariales sensu lato, was examined histologically for 6 of the 21 reported moss hosts, using light microscopy, scanning electron microscopy, and transmission electron microscopy. A unique mode of fungal biotrophy was encountered in 5 of the 6 mosses analyzed, in which E. muscicola exploits gametophytic host transfer cells concomitant with varying degrees of supplantation of the moss sporophyte. Basidiocarps are restricted in these mosses to postfertilized archegonia, in which they are seen to associate with the sporophyte foot region, where they gain access to the host transfer cell nutritional interface. Basidiocarp ontogeny is presented as it relates to the development of the host–parasite interface. The relationship of E. muscicola to other simple-septate auricularioid taxa and the the Uredinales is discussed.

Survey of Some Canadian Lakes for the Presence of Ultrastructurally Discrete Particles in the Colloidal Size Range

1979 ◽  
Vol 36 (8) ◽  
pp. 906-921 ◽  
Author(s):  
A. Massalski ◽  
Gary G. Leppard
Keyword(s):  
Electron Microscopy ◽  
Size Range ◽  
Trophic Levels ◽  
Clay Particles ◽  
Air Interface ◽  
Transmission Electron ◽  
Different Depths ◽  
Thin Section Analysis ◽  
Almost All ◽  
Section Analysis

Water samples from nine Canadian lakes were centrifuged and the pellets were analyzed by transmission electron microscopy. The pellets included small organisms, organic colloids, and clay particles. In almost all the samples, colloids were the major component revealed following thin-section analysis. When viewed at high magnification, much of each pellet consisted of morphologically discrete particles, some of which were readily categorized. Electron-opaque fibrils of colloidal size were frequently encountered (1) at different depths, (2) as a coating on the surface of algae and bacteria, (3) overlaying the sediments, (4) as an apparent adhesive between a variety of particles, and (5) as a component of froth at the water–air interface. They were common at all times and in lakes of various trophic levels and sizes. Key words: water, colloids, fibrils, lakes, electron microscopy

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