Advanced Analytical Techniques - Polymerase Chain Reaction (PCR)

The Polymerase Chain Reaction (PCR™) is a powerful enzyme-based tool that can increase

the concentration of genetic material within a sample by a millionfold or more in as little as a

few hours.  It has been successfully adapted toward the study of RNA and DNA obtained from environmental samples to facilitate the detection and analysis of microorganisms that may

cause disease, and also to help us to understand the fate and ecology of microorganisms in

the environment.

PCR Process

PCR can be employed for the detection of microorganisms in the aquatic environment by supplementing water concentrates with specific enzymes and short synthetic DNA 'primer' molecules that help to kick start the process.  Primers can be synthesized in the laboratory that

will bind only to the DNA or RNA of specific microbes.  When water concentrates containing these microbes are subjected to PCR assay, it is possible to increase the amount of genetic material dramatically within a few hours, to the extent that detection of the microbe using a standard electrophoretic gel can be performed within a day.  Because many important agents of infectious disease such as the enteric viruses grow very slowly in culture or cannot be cultured at all using

in vitro techniques, PCR makes it possible to detect the microorganisms that would otherwise

be missed using conventional assay techniques.

PCR at SMI

SMI utilizes PCR to identify disease causing bacteria and viruses.  SMI has 5 standard thermal cyclers as well as an in situ amplification unit that can accommodate living cells/tissues.  The results of PCR reactions are analyzed using agarose gel electrophoresis, with images digitized onto a UVP EPIChemi II Darkroom with a UV transilluminator.  A digital image of Aeromonas bacteria subjected to PCR assay is presented below.

                   DNA Thermal Cyclers                          Epi Chemi II Darkroom/UV Transilluminator

Epi Chemi II Darkroom - Interior View  

The following scans were acquired following electrophoretic separation of PCR reactions on Aeromonas isolates to identify strains that can cause disease in humans (e.g. A. hydrophila)

For further information about SMI's services, please feel to contact a project manager at (574) 277-4078.