Gramicidin is a mixture of three antibacterial polypeptides that work together to form a channel that spans cell membranes. As evidenced by these micrographs, oblique illumination adds a pseudo three-dimensional effect to images when compared to unaided brightfield microscopy.

The antibiotic increases the permeability of the bacterial cell membrane to inorganic cations by forming a network of channels through the normal lipid bilayer of the membrane. Medicinally, gramicidin is often used in a combination with other drugs for treating inflammation of the skin, eyes, and ears. Side effects include local irritation of areas with the applied drug.

Transmitted oblique illumination was obtained with a Hoffman-style substage condenser fitted with an offset aperture slit, which provides illumination from an oblique angle with respect to the optical axis of the QX3 microscope. Digital images were recorded with the QX3 interactive software operating from the Live View menu. In the case of birefringent specimens, a polarizer was added beneath the Hoffman condenser and an analyzer was placed in front of the QX3 lens cover. In some instances, a full-wave retardation plate was inserted between the specimen and the analyzer before capturing images.

BACK TO THE OBLIQUE (HOFFMAN) GALLERY

Questions or comments? Send us an email.

© 1995-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.

This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.

The QX3 microscope design is copyrighted © 2022 by Mattel, Inc. Intel® Play™ is a registered trademark of the Intel Corporation. These companies reserve all of their rights and privileges under copyright law. The material contained in this website is solely the opinion of the authors and is intended for eduational use only.

Last Modification Friday, Nov 13, 2015 at 01:19 PM

Access Count Since April 26, 2000: 11154

Visit the official Intel Play website:

Visit the websites of our partners in education: