Tag Archives: VptA

qPCR – V.tubiashii primers test (Vpt A and Vt IGS)

Utilized to sets of primers obtained from the Friedman Lab: VptA (referred to as “Hasegawa”, even though the reference article calls the primers Vtp A) and Vt IGS (referred to as “Lee” primers, presumably from a published article). For template, used “RE22 DNA” that was given to me by Elene. Tube is dated 9/10/09 and has no indication of concentration. Performed qPCR on a set of 10-fold dilutions. Plate layout/qPCR set up is here, along with dilution series used.


The VptA primer set generated a nice looking set of dilutions with appropriate spacing (~3.2 Ct/10-fold dilution). HOWEVER, the raw fluorescence signal is very low (only 0.4 units; good signal is usually 3-5-fold higher) AND the melting curve doesn’t look that great. The melting curve could look poor due to the low signal, since it doesn’t come up much higher than background levels.

It should be noted that the low fluorescence levels generated could simply be due to the amplicon size generated by these primers. The amplicon size is only 63bp. An amplicon of this size might not be able to incorporate significant amounts of dye to generate a “normal” level of fluorescence (1.25 – 2 units).

The Vt IGS primers failed to generate any product.