Tag Archives: DNased RNA

RNA Isolation – Dave’s Manila Clam (Venerupis philippinarum) Gill Samples (#25-48)

Isolated RNA from Manila Clam gill samples provided by Dave, according to protocol. Samples were resuspended in 0.1%-DEPC H2O and spec’d on the Roberts Lab NanoDrop1000. Samples were stored @ -80C in Dave’s box that the tissue was initially stored in.

Results:

All samples look great with excellent yields and great 260/280 values. Will proceed with DNasing. (Note: Sample #42 appears twice because the first reading had an air bubble and, as such, should be discarded.)

 

DNased RNA using Ambion’s Turbo DNA-free Kit following the “routine” protocol. 5ug of total RNA from each sample was treated in 50uL reactions. Samples will be spec’d on Monday with the Roberts Lab NanoDrop 1000.

Results:

qPCR – DNased RNA from earlier today

Checked DNased RNA samples from earlier today for the presence of residual gDNA. Used C.gigas BB16 gDNA (from 20110201) diluted to ~7ng/uL as a positive control to match the dilution factor of the RNA that will be used in the reverse transcription reaction (175ng in 25uL = 7ng/uL). All samples were run in duplicate. Master mix calcs are here. Plate layout, cycling params, etc can be found in the qPCR Report (see Results).

Results:

qPCR Data (CFX96)

qPCR Report (PDF)

Positive control (in Green in qPCR Report) worked perfectly and showed excellent repeatability. The remainder of the samples (in Blue in qPCR Report) and the NTCs (in Red in qPCR Report) were extremely inconsistent with many having one replicate show late amplification, while the other replicate showed no amplification at all. Will have to repeat to get a more definitive assessment of residual gDNA content in these samples.

Reverse Transcription – Hard Clam Gill DNased RNA (from 20110509)

Performed reverse transcription on DNased RNA from the hard clam vibrio tubiashii challenge experiment (see Dave’s Notebook 5/2/2011), following the Promega M-MLV RT protocol with ~1ug of DNAsed RNA. Master mix calcs are here. Reactions were done in a plate. cDNA was diluted 1:4 with H2O.

DNase – Hard Clam Gill RNA (from earlier today)

DNased 5ug of RNA from each sample with Ambion’s Turbo DNA-free Kit, according to the manufacturer’s rigorous protocol. Samples were spec’d and stored @ -80C in the “Hard Clam V.t. Experiment RNA” box.

Results:

Due to lack of a positive control (and lack of primers known to amplify gDNA), these DNased RNA samples will NOT be checked to verify elimination of gDNA carryover at this time. Will proceed with making cDNA for qPCR anyway.

Reverse Transcription – C.gigas BB/DH DNased RNA (from 20090507) for PROPS

Performed RT on DNased RNA using Promega MMLV RT and Oligo dT according to manufacturer’s protocol, using 1ug of DNased RNA, but in a 50uL reaction. Due to large number of samples, cDNA was made in PCR plate. Plate layout and calcs are here.

Reverse Transcription – C.gigas DNased RNA (from 20110131) from V.vulnificus Exposure & Tissues (from 20110111)

Performed RT on DNased RNA using Promega MMLV RT and Oligo dT according to manufacturer’s protocol, using 1ug of DNased RNA. Due to large number of samples, cDNA was made in PCR plate. Plate layout and calcs are here. cDNA was diluted 4-fold (to 100uL total volume) based on qPCR done by Emma on 20110202.

qPCR – Check DNased RNA BB01 for Residual gDNA (from earlier today)

Ran qPCR on DNased RNA from earlier today to verify removal of contaminating gDNA. Used C.gigas 18s primers (SR IDs: 156, 157). 0.5uL (~40ng) of DNased RNA was used for testing. This corresponds, roughly, to the amount of sample that would be carried through to qPCR analysis of cDNA, assuming 1ug of RNA was used to make the cDNA (cDNA = 1000ng RNA/25uL = 40ng/uL, 1uL of cDNA in 25uL qPCR reaction). Positive control sample was ~25ng BB16 gDNA (from 20090519). Master mix calcs are here. Plate layout, cycling params, etc can be found in the qPCR Report (see Results). RNA was stored @ -80C in “Sam’s -80C Box”.

Results:

qPCR Report (PDF)

qPCR Data File (CFX96)

Residual gDNA is present in the sample. So, it’s become apparent that it’s virtually impossible to rid the BB01 RNA of contaminating gDNA. Will discuss with Steven and Mac if it’s feasible to exclude this from the additional PROPS analysis that needs to be done and how this could potentially affect our data. Talked to Steven and, duh, we can just remove the previous BB01 data from our analysis. Will make new batch of cDNA from existing DNased RNA samples.

qPCR – Check DNased RNA BB01 for Residual gDNA (from earlier today)

Ran qPCR on DNased RNA from earlier today to verify removal of contaminating gDNA. Used C.gigas 18s primers (SR IDs: 156, 157). 0.75uL (~50ng) of DNased RNA was used for testing. This corresponds, roughly, to the amount of sample that would be carried through to qPCR analysis of cDNA, assuming 1ug of RNA was used to make the cDNA (cDNA = 1000ng RNA/25uL = 40ng/uL, 1uL of cDNA in 25uL qPCR reaction). Positive control sample was ~25ng BB16 gDNA (from 20090519). Master mix calcs are here. Plate layout, cycling params, etc can be found in the qPCR Report (see Results). RNA was stored @ -80C in “Sam’s -80C Box”.

Results:

qPCR Report (PDF)

qPCR Data File (CFX96)

Well, this sucks. Still gDNA contamination. Will just start with original RNA again and discard this “DNased” sample.

DNase – C.gigas BB01 from 20110225

Used EtOH precipitated BB01 RNA from 20110225 and followed Ambion’s “rigorous” protocol, utilizing a total of 2uL of DNAse. Briefly, samples were incubated @ 37C for 30mins, an additional 1uL of DNase was added to each sample, mixed and incubated for an additional 30mins @ 37C. After finishing protocol, samples were spec’d.

Results:

RNA looks good, based on the OD260/280. As usual after DNasing, the OD260/230 is on the low side. Will check for residual gDNA via qPCR.