ch2 - Study of Microbial Structure M icroscopy Specimen...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Study of Microbial Structure: Microscopy & Specimen Preparation
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Types of Microscopy Light Microscopes: Use light rays to help visualize the specimen 1000X TM possible Electron Microscopes: Uses a beam of electron radiation and capture to produce images Best resolution and greater magnification than light microscopes Requires expensive chemical preparation of specimens and sophisticated equipment
Background image of page 2
Light Microscopy 1. Brightfield: Images appear dark, background is white Specimens need either natural pigments or to be stained not good for live material Light passes directly through and around the specimen and up into the objective http://people.uleth.ca/~selibl/Biol3200/Mor phology04/MsAF.html http://www.microbiologybytes.com/ introduction/2101.html
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Light Microscopy 2. Darkfield: Images appear bright, background is dark No need for stain or pigments excellent for live material Light is blocked & scattered by a disc (patch stop) creating an outer ring of illumination The scattered light is collected and passed into the objective lens http://en.wikipedia.org/wiki/ File:Dark_Field_Microscope.png http://www.vardb.org/vardb/images.html
Background image of page 4
Light Microscopy 3. Phase Contrast: Images appear bright, background is dark No need for stain or pigments excellent for live material The light which passes through the specimen is recombined with the scattered light Produces images in which the dense structures appear darker than the background and a glow around their edges http://www.howstuffworks.com/ light-microscope.htm/printable http://people.uleth.ca/~selibl/Biol3200/Mor phology04/BtPHBPB.html
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Light Microscopy 4. Fluorescence: Uses dyes or natural pigments that produce light as a means to visualize the specimen some work for live cells Light is transmitted through the specimen using an excitation filter so only a certain range of wavelengths (i.e. blue) pass into the specimen Pigments/dyes emit a different wavelength of light (i.e. green) after excitation – only these wavelengths of light are transmitted to the eye after passage through a barrier filter http://homepages.ius.edu/DTREVES/ http://web.uvic.ca/ail/techniques/epi- fluorescence.html
Background image of page 6
Electron Microscopy 1. Transmission: Electron beam penetrates the specimen and then scatters Electrons bounce back to the
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 25

ch2 - Study of Microbial Structure M icroscopy Specimen...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online