Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
Use of Electron Microscope for Detection and Diagnosis of Pathogens in
Protected Cultivation
Introduction
Balwinder Singh
Department of Anatomy, G.B.P.U.A.&T., Pantnagar - 263145 (Uttarakhand)
One of the most important tasks in the education of a pathologist is learning to distinguish
normal from abnormal tissues. Typically, training
programs provide an adequate background for the
examination and interpretation of tissues at the
gross and light microscopic (lm) levels, leaving the
student pathologist to his/her own devices to
develop necessary skills at the ultrastructural level.
The purpose of this presentation is to facilitate
development of these skills in ultrastructural
examination/interpretation of tissues, by providing a
starting point, some tools for study, direction, and
finally, a goal at which to aim. Since it would be
unrealistic to attempt to go into depth in the short
time allotted, the presentation will concentrate on
an approach to interpretation of ultrastructural
cases while providing a broad overview of some
commonly examined tissues.
A human eye can distinguish two points 0.2mm apart. Man’s quest to see the unseen and
beyond what can be seen with the naked eye led to the discovery of simple magnifying glass that
produces an enlarged image of an object. Further improvement led to development of light
microscopes that use a combination of magnifying glasses/lenses. Dr.Ernst Ruska at the
University of Berlin built the first Electron Microscope (a Transmission Electron Microscope) in
1931 and could get a resolution of 100nm using two magnetic lenses. Today using 5-7 magnetic
lenses in the imaging system a resolution of 0.2nm can be achieved. The introduction of the
electron microscope as a tool for the biologist brought about a complete reappraisal of the microanatomy
of biological tissues, organisms and cells. In the early days of its application to biological
materials, it was the tool of anatomists and histologists, and many previously unimagined
structures in cells were revealed. More recent developments in biological specimen preparation
have come from biochemists and physicists who have used the electron microscope to examine
cells and tissue in many different ways.
The two most common types of electron microscopes available commercially are the
TRANSMISSION ELECTRON MICROSCOPE (TEM) and the SCANNING ELECTRON
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