THE DEVELOPMENT OF ECHINULATION IN UREDOSPORES OF WHEAT STEM RUST

1967 ◽  
Vol 45 (3) ◽  
pp. 287-289 ◽  
Author(s):  
P. L. Thomas ◽  
P. K. Isaac
Keyword(s):  
Electron Microscopy ◽  
Stem Rust ◽  
Wheat Stem Rust ◽  
Sequence Of Events ◽  
Pass Through ◽  
Mature Size

Electron microscopy was used to determine the sequence of events in the formation of spines on the uredospore walls of P. graminis tritici. The micrographs show that spines develop to mature size beneath the uredospore wall and then move or pass through the wall to its surface during the expansion and maturation of the spore.

Electron microscopy of susceptible and resistant near-isogenic (sr6/Sr6) lines of wheat infected by Puccinia graminis tritici. III. Ultrastructure of incompatible interact

1979 ◽  
Vol 57 (23) ◽  
pp. 2626-2634 ◽  
Author(s):  
D. E. Harder ◽  
D. J. Samborski ◽  
R. Rohringer ◽  
S. R. Rimmer ◽  
W. K. Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stem Rust ◽  
Stem Rust Resistance ◽  
Temperature Sensitive ◽  
Puccinia Graminis ◽  
Cell Necrosis ◽  
Mitochondrial Membranes ◽  
Wheat Stem Rust ◽  
Mesophyll Cells ◽  
Mother Cells

The interaction between avirulent wheat stem rust and wheat mesophyll cells containing the temperature-sensitive Sr6 gene for stem rust resistance was studied by electron microscopy. Mesophyll cells that were invaded at 26 °C (conditioning compatibility) did not develop any signs of incompatibility after they were transferred to 19 °C, at which temperature incompatibility is normally expressed. In host tissue that appeared to be invaded after the change from 26 to 19 °C, the early ultrastructural symptoms of incompatibility were a more electron-dense and often perforated invaginated host plasmalemma, disruptions of the noninvaginated host plasmalemma, vacuolation of the cytoplasm, and accumulations of electron-dense material along the membranes of the vacuoles. At later stages in the development of incompatible interactions, the electron-dense accumulations along the vacuole membranes increased in size and occurred along chloroplast and mitochondrial membranes. Eventually, the entire protoplasts were electron dense and collapsed. In haustoria and haustorial mother cells, incompatibility was usually expressed by a uniform increase in electron density of the cytoplasm. In the Sr6/P6 interaction at 19 °C, host cell necrosis was not always accompanied by fungal necrosis or vice versa. In Sr5/P5 interactions, which were examined for comparison, the intracellular symptoms of incompatibility were similar to those of the Sr6/P6 interactions.

scholarly journals The nucleolus of wheat stem rust uredospores

1969 ◽  
Vol 47 (12) ◽  
pp. 1887-1889 ◽  
Author(s):  
Stephen Mitchell ◽  
Michael Shaw
Keyword(s):  
Electron Microscopy ◽  
Ribosomal Rna ◽  
Stem Rust ◽  
Ribonucleic Acid ◽  
Acid Formation ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Puccinia Graminis Tritici ◽  
Mean Diameter

Electron microscopy shows that the nuclei in immature uredospores of Puccinia graminis tritici possess prominent nucleoli with a mean diameter of 1.7 ± 0.4 μ. The nucleoli in mature uredospores are much smaller (0.5 μ). This reduction in size of the nucleoli may indicate that ribosomal RNA (ribonucleic acid) formation is repressed as uredospores mature.

Nucleoli in differentiated germ tubes of wheat rust uredospores

1970 ◽  
Vol 48 (9) ◽  
pp. 1693-1695 ◽  
Author(s):  
Larry D. Dunkle ◽  
William P. Wergin ◽  
Paul J. Allen
Keyword(s):  
Electron Microscopy ◽  
Heat Shock ◽  
Nuclear Envelope ◽  
Outer Membrane ◽  
Ribosomal Rna ◽  
Stem Rust ◽  
Wheat Stem Rust ◽  
Cytoplasmic Structures ◽  
Germ Tubes ◽  
Wheat Rust

Nucleoli observed by electron microscopy are illustrated in germ tubes of wheat stem rust uredospores which have been induced by heat shock to differentiate infection structures. The presence of nucleoli in these structures suggests that this obligate parasite may possess the capacity of synthesizing ribosomal RNA independently of its host. In addition to nucleoli, heterochromatin is characteristically observed appressed to the inner membrane of the nuclear envelope. This material is associated with distinct cytoplasmic structures which are appressed to the outer membrane of the nuclear envelope and resemble developing centrioles in other fungi.

Albumin-Induced Endocytic Vacuoles in Tetrahymena Pyrijormis

1975 ◽  
Vol 33 ◽  
pp. 694-695
Author(s):  
L. J. Brenner ◽  
D. G. Osborne ◽  
B. L. Schumaker
Keyword(s):  
Electron Microscopy ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Protein Concentration ◽  
Tetrahymena Pyriformis ◽  
Sequence Of Events ◽  
Cytoplasmic Bodies ◽  
Food Vacuoles ◽  
Mouse Ascites ◽  
Normal Human

Exposure of the ciliate, Tetrahymena pyriformis, strain WH6, to normal human or rabbit sera or mouse ascites fluids induces the formation of large cytoplasmic bodies. By electron microscopy these (LB) are observed to be membrane-bounded structures, generally spherical and varying in size (Fig. 1), which do not resemble the food vacuoles of cells grown in proteinaceous broth. The possibility exists that the large bodies represent endocytic vacuoles containing material concentrated from the highly nutritive proteins and lipoproteins of the sera or ascites fluids. Tetrahymena mixed with bovine serum albumin or ovalbumin solutions having about the same protein concentration (7g/100 ml) as serum form endocytic vacuoles which bear little resemblance to the serum-induced LB. The albumin-induced structures (Fig. 2) are irregular in shape, rarely spherical, and have contents which vary in density and consistency. In this paper an attempt is made to formulate the sequence of events which might occur in the formation of the albumin-induced vacuoles.

Is there an electron wind?

1990 ◽  
Vol 48 (4) ◽  
pp. 798-799
Author(s):  
L. D. Marks ◽  
J. P. Zhang
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Zone Axis ◽  
Electron Holography ◽  
Electron Wave ◽  
Small Particles ◽  
Resolution Electron ◽  
Pass Through ◽  
Electron Wind ◽  
Inelastic Scatter

A not uncommon question in electron microscopy is what happens to the momentum transferred by the electron beam to a crystal. If the beam passes through a crystal and is preferentially diffracted in one direction, is the momentum ’lost’ by the beam transferred to the crystal? Newton’s third law implies that this must be the case. Some experimental observations also indicate that this is the case; for instance, with small particles if the particles are supported on the top surface of a film they often do not line up on the zone axis, but if they are on the bottom they do. However, if momentum is transferred to the crystal, then surely we are dealing with inelastic scattering, not elastic scattering and is not the scattering probability different? In addition, normally we consider inelastic scatter as incoherent, and therefore the part of the electron wave that is inelastically scattered will not coherently interfere with the part of the wave that is scattered; but, electron holography and high resolution electron microscopy work so the wave passing through a specimen must be coherent with the wave that does not pass through the specimen.

Retrospective analysis of virulence of the North Caucasian population of wheat stem rust pathogen

2019 ◽  
Vol 1 (81) ◽  
pp. 85-90
Author(s):  
Galina Volkova ◽  
◽  
Olesya Miroshnichenko ◽  
Olga Tarancheva ◽  
◽  
...  
Keyword(s):  
Retrospective Analysis ◽  
Stem Rust ◽  
Caucasian Population ◽  
Wheat Stem Rust ◽  
The North ◽  
Rust Pathogen
Sign in / Sign up

Export Citation Format

Share Document