the microscope must accomplish three tasks 1. produce a magnified image of the specimen
DESCRIPTION
Microscopy - an introduction. Microscopes are instruments designed to produce magnified visual or photographic images of small objects. The microscope must accomplish three tasks 1. produce a magnified image of the specimen separate the details in the image, - PowerPoint PPT PresentationTRANSCRIPT
• Microscopes are instruments designed to produce magnified visual or photographic images of small objects.
The microscope must accomplish three tasks1. produce a magnified image of the specimen 2. separate the details in the image, 3. render the details visible to the human eye or camera.
Microscopy - an introduction
Light Microscopes
Electron Microscopes• The use of high energy electrons to examine the
fine details of objects.
Major Types of electron microscopes.
• Scanning electron microscope (SEM).
• Transmission electron microscope (TEM)
Scanning electron microscopy (SEM).
Types of specimens:
-Whole organisms
-Natural tissue surfaces
-Exposed tissue structure
-Corrosion casts
SEM of Penicillium islandicum
Transmission electron microscopy (TEM).
• Allows the observation of molecules within cells
• Allows the magnification of objects in the order of 100, 000’s.
Representative EM images of Pst DC3000 avrPto (pAVRPTO), immunogold-labeled with the AvrPto antibody. In situ immunogold labeling was done after bacteria were grown in hrp-inducing medium for 4 hours, supplemented with (A) no SA, (B) SA for 4 hours, or (C and D) SA for 1 hour. Dark dots are 15-nm gold particles in (A) and (C) and 10-nm gold particles in (B) and (D). Arrows indicate Hrp pili attached to rod-shaped bacteria (only a portion of the bacterium is shown, surrounded by dark stain). Scale bars, 100 nm.