The Pathogenesis of Experimental Mycotic Encephalitis

1969 ◽  
Vol 27 ◽  
pp. 356-357
Author(s):  
James A. Swenberg ◽  
Adalbert Koestner ◽  
R.P. Tewari
Keyword(s):  
Electron Microscopy ◽  
Pathogenetic Mechanisms ◽  
Host Parasite

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

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)

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

1966 ◽  
Vol 44 (5) ◽  
pp. 669-673 ◽  
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.

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.

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

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.

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

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 ◽  
Host Parasite

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.

scholarly journals HOST-PARASITE INTERACTION IN THE RAT RENAL PELVIS

1974 ◽  
Vol 140 (6) ◽  
pp. 1696-1711 ◽  
Author(s):  
Fredric J. Silverblatt
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Female Rats ◽  
Mucosal Barrier ◽  
Type Iii ◽  
Type Iv ◽  
Predominant Type ◽  
Initial Interaction ◽  
Host Parasite

The initial interaction between bacteria and the renal pelvic epithelium may determine whether intrarenal infection occurs. A model of retrograde pyelonephritis was employed to study these events by electron microscopy. Female rats received an intravesicular inoculation of a 0.5-ml suspension of Proteus mirabilis containing 108 organisms. At intervals after inoculation, the kidneys were fixed by intravascular perfusion and the tissues were prepared for electron microscopy. During the first 24 h, increasing numbers of bacteria were seen to be attached by pili to the renal pelvic epithelial cells. The organism appeared to cross the mucosal barrier by several mechanisms: (a) penetration into the cytoplasm of intact epithelial cells, (b) passage between epithelial cells that were separated by excessive hydrostatic pressure generated during bladder inoculation, (c) passage across necrotic regions of the pelvis, and (d) translocation to the cortex by calicotubular backflow. Whereas at inoculation bacteria possessed pili 40 Å in diameter (type III pili) 24 h after reflux, the predominant type of pili measured 70 A in thickness (type IV pili). Repetitive subculture induced a similar transition in vitro. To assess the influence of pili type on virulence in this model, 80 rats were challenged with either type III or type IV pilated organisms and the frequency of rats with cortical abscesses were compared at 1 wk. A significantly greater number of rats inoculated with type IV pilated Proteus manifested macroscopic evidence of infection. These results suggest that pili play a role in the pathogenesis of ascending pyelonephritis.

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