We are virtually out of the withering syndrome qPCR standard curve plasmid dilutions and I need to send some to Colleen Burge at Univ. of Maryland Baltimore County. As such, I’ll need to make a fresh dilution series and test it out prior to sending to her.
Used NcoI-linearized p18RK7 abalone withering syndrome plasmid (from 20120726) to make a fresh dilution series.
Since it’s been nearly 4yrs since the plasmid was prepared, I decided to re-quantify the DNA using a Qubit3 (Life Technologies) in the Roberts Lab. Used the dsDNA BR Qubit reagents.
The result is pretty close to what had been measured 4yrs ago (~26.1ng/μL – difference of ~10%), so that’s good to see.
I prepared the dilution series using IDTE (pH=8.0; IDT) Buffer. The dilution worksheet below was set up by Nate Wight many, many, moons ago.
After designing new primers for use in Withering Syndrome phage (RLOv) identification on 20150706, ran Primer-BLAST via NCBI’s website to assess primer specificity. Ran Primer-BLAST with each primer set against the NCBI nr Viruses (Tax ID:10239 ) and Prokaryotes (Tax ID: 2) nucleotide databases. Excluded uncultured/environmental samples from the databases. The general setting for the Primer-BLASTs can be seen in the screen capture below. Entered in each primer set in the “Primer Parameters” boxes.
The Primer-BLAST only exhibits an output if either of the primers produce a match. When primers do have a match in the database, an alignment of primer(s) is shown on the matching template. Dots in the alignment are exact nucleotide matches, whereas mismatched nucleotides are simply displayed with their corresponding letter in the alignment.
Stan Langevin recently annotated the Withering Syndrome (WS) bacteriophage genome he previously assembled. Additionally, after discussing with Carolyn, they decided on two new potential qPCR targets and three potential in-situ hybridization (ISH) targets. Stan provided a FASTA file with the five sequences and primers were designed using Primer3Plus.
For qPCR primers, amplicon length range was set to 150-250bp. Additionally, I had Primer3Plus design an internal primer for potential future use as a fluorescent probe, should we ever establish one of these qPCRs as a validated WS phage assay.
The ISH primers amplicon length range was set to 400-500bp.
All primers (excluding probes) will be ordered from IDT.
Ran qPCRs on remaining 2011 water filter DNA samples. All samples were from The Cultured Abalone farm, but some samples are abbreviated “CAB”, while others “TCA”. Samples were extracted 20131001 and 20131120.
Today’s qPCR data matches up very well with the initial qPCR data.
Clearly, there is something odd about the aliquots that were sent to Alice (and back) for use in ddPCR. I can’t really fathom what happened. Will contact Alice and see if she’d like to try out new aliquots of these samples to see how the ddPCR turns out (again).
The table certainly shows some inconsistency, both between ddPCR and qPCR. Additionally, there is also inconsistency between the initial qPCRs and today’s qPCRs. Due to the limited sample volumes remaining for these sub-samples that were sent to Alice and then returned to us, I will repeat the qPCR using the stock DNA and see how that compares.