ELECTRON MICROSCOPY OF THE HOST-PARASITE RELATIONSHIPS IN STEM RUST OF WHEAT

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062154 ◽

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.

Ultrastructural karyology of Spongospora subterranea (Plasmodiophoromycetes)

10.1139/b92-155 ◽

1992 ◽

Vol 70 (6) ◽

pp. 1228-1233 ◽

Cited By ~ 5

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 PHYSIOLOGY OF HOST–PARASITE RELATIONS: XVI. FINE STRUCTURE OF THE NUCLEUS IN THE RUST-INFECTED MESOPHYLL CELLS OF WHEAT

10.1139/b66-080 ◽

1966 ◽

Vol 44 (5) ◽

pp. 669-673 ◽

Cited By ~ 11

Author(s):

M. S. Manocha ◽

Michael Shaw

Keyword(s):

Electron Microscopy ◽

Fine Structure ◽

Electron Density ◽

Mesophyll Cells ◽

Host Parasite ◽

Late Stages ◽

Dense Chromatin

The nuclei in rust-infected mesophyll cells of Little Club wheat were examined by electron microscopy. There was a marked increase in the electron density of the diffuse, interchromatin regions of the nuclei at a stage in rust development (8 days after inoculation) at which two- to three-fold increases in RNA are known to occur. In the late stages of rust development (20 to 23 days after inoculation) the interchromatin material disappeared and the dense chromatin disintegrated.

Host-Parasite Relations in a Mycoparasite. VII. Light and Scanning Electron Microscopy of Interactions of Piptocephalis Virginiana with Host and Nonhost Species

Mycologia ◽

10.1080/00275514.1981.12021426 ◽

1981 ◽

Vol 73 (5) ◽

pp. 976-987 ◽

Cited By ~ 2

Author(s):

M. S. Manocha ◽

Roya Golesorkhi

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Host Parasite ◽

Scanning Electron

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

10.1139/b82-106 ◽

1982 ◽

Vol 60 (6) ◽

pp. 825-837 ◽

Cited By ~ 14

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.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: XVIII. DISTRIBUTION OF TRITIUM-LABELLED CYTIDINE, URIDINE, AND LEUCINE IN WHEAT LEAVES INFECTED WITH THE STEM RUST FUNGUS

10.1139/b67-062 ◽

1967 ◽

Vol 45 (5) ◽

pp. 555-563 ◽

Cited By ~ 13

Author(s):

P. K. Bhattacharya ◽

Michael Shaw

Keyword(s):

Stem Rust ◽

Rust Fungus ◽

Host Cells ◽

Fungal Mycelium ◽

Puccinia Graminis ◽

Mesophyll Cells ◽

Wheat Leaves ◽

Wheat leaves were detached 6 days after inoculation with the stem rust fungus (Puccinia graminis var. tritici Erikss. and Henn.) and fed with tritiated leucine, cytidine, uridine, or thymidine. Mesophyll cells in infected zones incorporated more leucine into protein and more cytidine and uridine into RNA than did cells in adjacent uninfected tissue. Leucine, cytidine, and uridine were also heavily incorporated by fungal mycelium and developing uredospores. Grain counts over host nuclei in the infected zone were two to three-fold of those over nuclei in adjacent uninfected zones. There was no detectable incorporation of thymidinemethyl-3H into either the fungus or the host cells. The results are discussed.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: X. THE METABOLISM OF INDOLEACETIC ACID-1-C14 BY WHEAT AND OAT COLEOPTILE SECTIONS, UNINFECTED AND RUSTED WHEAT LEAVES AND UREDOSPORES OF WHEAT STEM RUST

10.1139/b62-047 ◽

1962 ◽

Vol 40 (3) ◽

pp. 511-521 ◽

Cited By ~ 6

Author(s):

B. I. Sahai Srivastava ◽

Michael Shaw ◽

R. J. Woods

Keyword(s):

Stem Rust ◽

Indoleacetic Acid ◽

Water Soluble ◽

Wheat Stem Rust ◽

Resistant Species ◽

Metabolic Products ◽

Soluble Compound ◽

Wheat Leaves ◽

Insoluble Compounds ◽

Coleoptiles of Little Club wheat and Brighton oats, uninfected and rusted leaves of Little Club and Khapli wheats and uredospores of stem rust were incubated with 10 or 100 parts per million of indoleacetate-C14OOK (IAA) in distilled water in darkness. The metabolic products formed were extracted by boiling the incubation medium. This was then partitioned with ether and the aqueous and ether fractions were analyzed by paper chromatography. In the coleoptiles and uninfected and rusted wheat leaves 8–14 different Ehrlich- or Salkowski-positive radioactive products of IAA metabolism were detected. These were not found when the plant material was incubated with water alone. One ether-soluble compound, and four ether-insoluble compounds from wheat coleoptiles had ultraviolet spectra of the indole type and were found to be active in the Avena straight growth test. IAA and its ether-soluble products disappeared more rapidly from uninfected than from rust-infected Little Club wheat leaves. Four water-soluble, radioactive products were found in uninfected leaves but only two in rusted leaves. A substance tentatively identified as indolecarboxylic acid (ICA) was not found in Little Club wheat leaves until 16 days after rust infection, but was present in both uninfected and infected leaves of the resistant species, Khapli. Uredospores apparently converted IAA only to nonradioactive decarboxylation products, tentatively identified as ICA and indolealdehyde. The results are discussed and attention is drawn to the importance of ether-insoluble products of IAA metabolism.

The Study of Stalk Rot and Causal Organisms via Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094450 ◽

1972 ◽

Vol 30 ◽

pp. 240-241

Author(s):

Judith A. Murphy

Keyword(s):

Electron Microscopy ◽

Living Cells ◽

Economic Importance ◽

Positive Correlation ◽

Stalk Rot ◽

Host Parasite Interactions ◽

Parenchyma Cells ◽

Host Parasite ◽

Natural Cell ◽

Scanning Electron

Cooperative SIU Research Includes: A. J. Pappelis, W. E. Schmid, O. Myers, Jr. (Botany); J. N. Bemiller, C. Hinckley (Chemistry); and J. Murphy (Center for Electron Microscopy).Stalk rot of corn is a disease costing millions of dollars annually. Because of the economic importance of this disease, many studies have been undertaken on the nature of resistance to stalk rot, host-parasite interactions, as well as studies of the various pathogens causing stalk rot.In studying the number of mechanisms for stalk rot resistance, A. J. Pappelis discovered a positive correlation between stalk rot susceptibility to Diplodia maydis and the pattern of natural cell death of parenchyma cells in the stalk and a positive correlation between disease resistance and the presence of living cells in that tissue.

Development and ultrastructure observations of secondary hyphae of Podosphaera leucotricha on apple cultivars of varying susceptibility to powdery mildew

Plant Protection Science ◽

10.17221/10513-pps ◽

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 ◽

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.