||high school biology, independent study/science fair, introductory undergraduate microbiology, advanced college level microbiology|
|Revision Date||July 2, 2004|
This exercise describes the construction of a biofilm model using data obtained from a mixed biofilm of Pseudomonas aeruginosa, P. fluorescens and Klebsiella pneumoniae.
Students should be able to define a biofilm, describe the differences between biofilm (surface-attached) and planktonic (suspended bacterial cells) bacteria, and describe HOW bacteria tend to grow on surfaces.
Given readily accessible materials, and the image series associated with this exercise, the instructor or the student will be able to make a biofilm model from foam board, Styrofoam or other similar material that will illustrate the basic structure of a biofilm.
A finished and working reactor system will be shown to the students.
A Confocal Scanning Laser Microscope is to optics what an MRI is to x-rays. It is a microscope that can record a visual slice of heavily hydrated material attached to a surface. Biofilms are such materials and the introduction of the CSLM has revolutionized our view of the structure and complexity of biofilms. A CSLM records an image of a thin slice of a biofilm at a particular focal point, the substrate surface for example, and stores this image in a computer. The instrument then moves to another image plane and records another image. This process is repeated from the substrate surface until the top of the biofilm is reached. The computer can then manipulate this series of images to produce xy (length and width) xz (length and depth) or three-dimensional images. This sort of image processing software is not commonly available in an undergraduate laboratory. Nevertheless, using those same images, one can produce a three-dimensional model which students can use to understand biofilm complexity and structure.
J. Lennox, Penn State Altoona
Figure 1. Biofilm Model
|2||sets of confocal images (see Attachments below)|
|NA||white glue or other type of glue|
|1||wood, plastic or cardboard base (approximately 12 x 20 cm)|
|As Necessary||sheets of 1/4 inch foam board, Styrofoam, or some other material from which the
model can be constructed
|1||coping saw, model saw or jig saw|
|As Necessary||safety goggles|
The student should be able to describe/determine:
Confocal laser scanning microscopy for analysis of microbial biofilms. Lawrence JR, Neu TR. Methods in Enzymology 1999; 310:11-144
Supported in part by the Waksman Foundation for Microbiology
Developed in collaboration with Dr. John Lennox, Penn State University-Altoona
© 1999-2008 Center for Biofilm Engineering, http://www.cbe.montana.edu