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Smearing of Positive DNA Samples - (Nov/17/2005 )


I have recntly started using the Taq Polymerase by Promega and I make my TaqMix by adding dNTPs, reaction buffer and the Taq polymerase enzyme. I used to use "Taq and Go" by Qbiogene. I have recently ran several PCRS and on my expected posiive samples I had smears for the length of the hyperladder. This is regardless of whether I use 250nM or 10uM primer concentrations. The negative lanes stay nehgative so I dont think it is mass contamination. Any ideas anyone as since I have changed Taq I am going backwards!! The primers were for Lactobacilli sp. Please see TIFF image to see what I mean. Lane 1 is hyperladder, Lanes 2 and 3 are L. casei and L. acidophilus, Lane 3 is E.coli and Lane 4 is control (MG water) using 250nm of each primer.
Lanes 6 and 7 are L. casei and L. acidophilus, Lane 8 is E.coli and Lane 9 is control (MG water) using 10um of each primer.




Hi, I cant see the figure, can you repost...