Suitability of Electron Microscopy for Routine Diagnosis of Plant Virus Diseases in Extension Service

Author(s):  
Joachim Hamacher ◽  
Rainer Giersiepen ◽  
Monika Heupel
Author(s):  
O. E. Bradfute

Electron microscopy is frequently used in preliminary diagnosis of plant virus diseases by surveying negatively stained preparations of crude extracts of leaf samples. A major limitation of this method is the time required to survey grids when the concentration of virus particles (VPs) is low. A rapid survey of grids for VPs is reported here; the method employs a low magnification, out-of-focus Search Mode similar to that used for low dose electron microscopy of radiation sensitive specimens. A higher magnification, in-focus Confirm Mode is used to photograph or confirm the detection of VPs. Setting up the Search Mode by obtaining an out-of-focus image of the specimen in diffraction (K. H. Downing and W. Chiu, private communications) and pre-aligning the image in Search Mode with the image in Confirm Mode facilitates rapid switching between Modes.


Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 456
Author(s):  
Benito Chen-Charpentier

Plants are vital for man and many species. They are sources of food, medicine, fiber for clothes and materials for shelter. They are a fundamental part of a healthy environment. However, plants are subject to virus diseases. In plants most of the virus propagation is done by a vector. The traditional way of controlling the insects is to use insecticides that have a negative effect on the environment. A more environmentally friendly way to control the insects is to use predators that will prey on the vector, such as birds or bats. In this paper we modify a plant-virus propagation model with delays. The model is written using delay differential equations. However, it can also be expressed in terms of biochemical reactions, which is more realistic for small populations. Since there are always variations in the populations, errors in the measured values and uncertainties, we use two methods to introduce randomness: stochastic differential equations and the Gillespie algorithm. We present numerical simulations. The Gillespie method produces good results for plant-virus population models.


1983 ◽  
Vol 12 (2) ◽  
pp. 24 ◽  
Author(s):  
GR Johnstone ◽  
D Munro ◽  
PJ Sampson

2019 ◽  
pp. 101-128 ◽  
Author(s):  
J. R. Edwardson ◽  
R. G. Christie ◽  
D. E. Purcifull ◽  
M. A. Petersen
Keyword(s):  

1984 ◽  
Vol 93 (4) ◽  
pp. 397-406 ◽  
Author(s):  
V Muniyappa ◽  
G K Veeresh
Keyword(s):  

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