Tag Archives: Crassostrea virginica

DNA Sonication & Bioanalzyer – C. virginica gDNA for MeDIP

I transferred 8ug (136uL) of Crassotrea virginica gDNA (isolated earlier today) to two separate 1.7mL snap cap tubes for sonication/shearing.

I performed shearing at the NOAA Northwest Fisheries Science Center, using the Qsonica Q800R. Mackenzie Gavery assisted me.

Target fragment size was ~500bp.

Samples were run at the same time with the following settings:

  • 10 minutes
  • 30 seconds on, 30 seconds off
  • 25% power

After sonication, fragmentation was assessed using the Seeb Lab’s Bioanlyzer 2100 (Agilent) and the DNA 12000 Chip Kit (Agilent). NOTE: All of the reagents and the chips were past their expiration dates (most in June 2016).


Agilent 2100 Bioanalyzer Expert file (XAD): 2100 expert_DNA 12000_DE72902486_2017-12-11_13-45-31.xad

Fragmentation was successful, and pretty consistent.

Both samples appear to have an average fragment size of ~420bp. Will proceed with MeDIP, once reagents are received.

Unsheared gDNA:


DNA Isolation & Quantification – Crassostrea virginica Mantle gDNA

DNA was isolated from a single adult Eastern oyster (Crassostrea virginica) for a pilot project with Qiagen to test their new DNA bisulfite conversion kit. The oyster was obtained yesterday afternoon (20171210) from the Taylo rShellfish Pioneer Square location. The oyster was stored @ 4C O/N.

The oyster was shucked and four pieces of upper mantle tissue (~35mg each) were snap frozen in liquid nitrogen (LN2). Tissues were pulverized under LN2 and then DNA was isolated separately from each sample using the E.Z.N.A. Mollusc DNA Kit (Omega) according to the manufcaturer’s protocol.

Samples were eluted with 100uL of Elution Buffer and were pooled into a single tube.

The gDNA was quantified using the Qubit 3.0 (Invitrogen) and Qubit dsDNA Broad Range Kit (Invitrogen), using 5uL of sample.


Qubit (Google Sheet): 20171211_qubit_virginica_DNA

Concentration is 58.4ng/uL.

That makes the total yield ~23.36ug (23360ng). This is more than enough to perform two separate MeDIP preps and two separate reduced representation digestions with MspI.

Will proceed with shearing of DNA for MeDIP.


DNA Isolation & Quantification – C. virginica Gonad gDNA

I isolated DNA from the Crassotrea virginica gonad samples sent by Katie Lotterhos using the E.Z.N.A. Mollusc Kit with the following modifications:

  • Samples were homogenized with plastic, disposable pestle in 350μL of ML1 Buffer
  • No optional steps were used
  • Eluted each in 100μL of Elution Buffer and pooled into a single sample

NOTE: Sample 034 did not process properly (no phase separation after 24:1 chlorform:IAA addition – along with suggested additions of ML1 Buffer) and was discarded.

Quantified the DNA using the Qubit dsDNA BR Kit (Invitrogen). Used 2μL of DNA sample.

Samples were stored in the same box the tissue was delivered in and stored in the same location in our -80C: rack 8, row 5, column 4.


Qubit (Google Sheet): 20171114_qubit_Cvirginica_gDNA

Ample DNA in all samples for MBDseq. (Refer to “Original Sample Conc.” column in spreadsheet.)

Will let Steven & Katie know.


Samples Received – C.virginica gonad tissue from Katie Lotterhos

Received and stored @-80C in rack 8, row 5, column 5.

The following information was sent with the samples:

Sample.ID Date Temp pCO2 Notes
031 26-Aug-2016 15 400
032 26-Aug-2016 15 400
033 26-Aug-2016 15 400
034 26-Aug-2016 15 400
035 26-Aug-2016 15 400 All sample sent; it will be in 2mL screw-cap vial
036 26-Aug-2016 15 400
103 26-Aug-2016 15 2800
104 26-Aug-2016 15 2800
105 26-Aug-2016 15 2800
106 26-Aug-2016 15 2800 All sample sent; it will be in 2mL screw-cap vial
108 26-Aug-2016 15 2800

Katie sent this additional info in an email to Steven and me:

These C. virginica samples were exposed to control (400, 6 samples) and OA (2800, 5 samples) conditions for ~4 weeks at 15C. Gonad was carefully extracted by peeling back the outer membrane, flash frozen in liquid N, and placed in -80C (until today when we removed it). During sampling, it was difficult to get a lot of what we considered “pure” gonadal tissue. We sent you ~1/2 of the amount of tissue we have for all samples except for the two samples which were very low and we sent you all the tissue sample we have. Each should be about 10-20 mg of tissue, which I’m worried is not enough for MBD-BS seq. Fingers crossed.


Goals – May 2015

Here are the things I plan to tackle throughout the month of May:

Geoduck Reproductive Development Transcriptomics

My primary goal for this project is to successfully isolate RNA from the remaining, troublesome paraffin blocks that have yet to yield any usable RNA. The next approach to obtain usable quantities of RNA is to directly gouge tissue from the blocks instead of sectioning the blocks (as recommended in the PAXgene Tissue RNA Kit protocol). Hopefully this approach will eliminate excess paraffin, while increasing the amount of input tissue. Once I have RNA from the entire suite of samples, I’ll check the RNA integrity via Bioanalyzer and then we’ll decide on a facility to use for high-throughput sequencing.


BS-Seq Illumina Data Assembly/Mapping

Currently, there are two projects that we have performed BS-Seq with (Crassostrea gigas larvae OA (2011) bisulfite sequencing and LSU C.virginica Oil Spill MBD BS Sequencing) and we’re struggling to align sequences to the C.gigas genome. Granted, the LSU samples are C.virginica, but the C.gigas larvae libraries are not aligning to the C.gigas genome via standard BLASTn or using a dedicated bisulfite mapper (e.g. BS-Map). I’m currently BLASTing a de-novo assembly of the C.gigas larvae OA 400ppm sequencing that Steven made against the NCBI nt DB in an attempt to assess the taxonomic distribution of the sequences we received back. I’ll also try using a different bisulfite mapper, bismark, that Mackenzie Gavery has previously used and has had better results with than BS-Map.


C.gigas Heat Stress MeDIP/BS-Seq

As part of Claire’s project, there’s still some BS-Seq data that would be nice to have to complement the data she generated via microarray. It would be nice to make a decision about how to proceed with the samples. However, part of our decision on how to proceed is governed by the results we get from the two projects above. Why do those two projects impact the decision(s) regarding this project? They impact this project because in the two projects above, we produced our own BS-Seq libraries. This is extremely cost effective. However, if we can’t obtain usable data from doing the library preps in-house, then that means we have to use an external service provider. Using an external company to do this is significantly more expensive. Additionally, not all companies can perform bisulfite treatment, which limits our choices (and, in turn, pricing options) on where to go for sequencing.



When I have some down time, I’ll continue working on migrating my Wikispaces notebook to this notebook. I only have one year left to go and it’d be great is all my notebook entries were here so they’d all be tagged/categorized and, thus, be more searchable. I’d also like to work on adding README files to our plethora of electronic data folders. Having these in place will greatly facilitate the ability of people to quickly and more easily figure out what these folders contain, file formats within those folders, etc. I also have a few computing tips/tricks that I’d like to add to our Github “Code” page. Oh, although this isn’t really lab related, I was asked to teach the Unix shell lesson (or, at least, part of it) at the next Software Carpentry Workshop that Ben Marwick is setting up at UW in early June. So, I’m thinking that I’ll try to incorporate some of the data handling stuff I’ve been tackling in lab in to the lesson I end up teaching. Additionally, going through the Software Carpentry materials will help reinforce some of the “fundamental” tasks that I can do with the shell (like find, cut and grep).

In the lab, I plan on sealing up our nearly overflowing “Broken Glass” box and establishing a new one. I need to autoclave, and dispose of, a couple of very full biohazard bags. I’m also going to vow that I will get Jonathan to finally obtain a successful PCR from his sea pen RNA.


Quality Trimming – LSU C.virginica Oil Spill MBD BS-Seq Data

Jupyter (IPython) Notebook: 20150414_C_virginica_LSU_Oil_Spill_Trimmomatic_FASTQC.ipynb

NBviewer: 20150414_C_virginica_LSU_Oil_Spill_Trimmomatic_FASTQC.ipynb

Trimmed FASTQC

NB3 No oil Index – ACAGTG


NB6 No oil Index – GCCAAT


NB11 No oil Index – CAGATC


HB2 25,000ppm oil Index – ATCACG


HB16 25,000ppm oil Index – TTAGGC


HB30 25,000ppm oil Index – TGACCA



Sequence Data Analysis – LSU C.virginica Oil Spill MBD BS-Seq Data

Performed some rudimentary data analysis on the new, demultiplexed data downloaded earlier today:



Compared total amount of data (in gigabytes) generated from each index. The commands below send the output of the ‘ls -l’ command to awk. Awk sums the file sizes, found in the 5th field ($5) of the ‘ls -l’ command, then prints the sum, divided by 1024^3 to convert from bytes to gigabytes.


$ls -l 2112_lane1_AC* | awk '{sum += $5} END {print sum/1024/1024/1024}'



$ls -l 2112_lane1_AT* | awk '{sum += $5} END {print sum/1024/1024/1024}'



$ls -l 2112_lane1_CA* | awk '{sum += $5} END {print sum/1024/1024/1024}'



$ls -l 2112_lane1_GC* | awk '{sum += $5} END {print sum/1024/1024/1024}'



$ls -l 2112_lane1_TG* | awk '{sum += $5} END {print sum/1024/1024/1024}'



$ls -l 2112_lane1_TT* | awk '{sum += $5} END {print sum/1024/1024/1024}'


Ran FASTQC on the following files downloaded earlier today. The FASTQC command is below. This command runs FASTQC in a for loop over any files that begin with “2212_lane2_C” or “2212_lane2_G” and outputs the analyses to the Arabidopsis folder on Eagle:

$for file in /Volumes/nightingales/C_virginica/2112_lane1_[ATCG]*; do fastqc "$file" --outdir=/Volumes/Eagle/Arabidopsis/; done


From within the Eagle/Arabidopsis folder, I renamed the FASTQC output files to prepend today’s date:

$for file in 2112_lane1_[ATCG]*; do mv "$file" "20150413_$file"; done


Then, I unzipped the .zip files generated by FASTQC in order to have access to the images, to eliminate the need for screen shots for display in this notebook entry:

$for file in 20150413_2112_lane1_[ATCG]*.zip; do unzip "$file"; done


The unzip output retained the old naming scheme, so I renamed the unzipped folders:

$for file in 2112_lane1_[ATCG]*; do mv "$file" "20150413_$file"; done


The FASTQC results are linked below:




Sequence Data – LSU C.virginica Oil Spill MBD BS-Seq Demultiplexed

I had previously contacted Doug Turnbull at the Univ. of Oregon Genomics Core Facility for help demultiplexing this data, as it was initially returned to us as a single data set with “no index” (i.e. barcode) set for any of the libraries that were sequenced. As it turns out, when multiplexed libraries are sequenced using the Illumina platform, an index read step needs to be “enabled” on the machine for sequencing. Otherwise, the machine does not perform the index read step (since it wouldn’t be necessary for a single library). Surprisingly, the sample submission form for the Univ. of Oregon Genomics Core Facility  doesn’t request any information regarding whether or not a submitted sample has been multiplexed. However, by default, they enable the index read step on all sequencing runs. I provided them with the barcodes and they demultiplexed them after the fact.

I downloaded the new, demultiplexed files to Owl/nightingales/C_virginica:


Notice that the file names now contain the corresponding index!

Renamed the files, to append the order number to the beginning of the file names:

$for file in lane1*; do mv "$file" "2112_$file"; done

New file names:


Updated the checksums.md5 file to include the new files (the command is written to exclude the previously downloaded files that are named “2112_lane1_NoIndex_”; the [^N] regex excludes any files that have a capital ‘N’ at that position in the file name):

$for file in 2112_lane1_[^N]*; do md5 "$file" >> checksums.md5; done

Updated the readme.md file to reflect the addition of these new files.



Epinext Adaptor 1 Counts – LSU C.virginica Oil Spill Samples

Before contacting the Univ. of Oregon facility for help with this sequence demultiplexing dilemma, I contacted Epigentek to find out what the other adaptor sequence that is used in the EpiNext Post-Bisulfite DNA Library Preparation Kit (Illumina). I used grep and fastx_barcode_splitter to determine how many reads (if any) contained this adaptor sequence. All analysis was performed in the embedded Jupyter (IPython) notebook embedded below.

NBviewer: 20150317_LSU_OilSpill_EpinextAdaptor1_ID.ipynb



This adaptor sequence is not present in any of the reads in the FASTQ file analyzed.


TruSeq Adaptor Counts – LSU C.virginica Oil Spill Sequences

Initial analysis, comparing barcode identification methods, revealed the following info about demultiplexing on untrimmed sequences:

Using grep:

long barcodes: Found in ~12% of all reads

short barcodes: Found in ~25% of all reads

Using fastx_barcode_splitter:

long barcodes, beginning of line: Found in ~15% of all reads

long barcodes, end of line: Found in < 0.008% of all reads (yes, that is actually percentage)

short barcodes, beginning of line: Found in ~1.3% of all reads

short barcodes, end of line: Found in ~2.7% of all reads


Decided to determine what percentage of the sequences in this FASTQ file have just the beginning of the adaptor sequence (up to the 6bp barcode/index):


This was done to see if the numbers increased without the barcode index (i.e. see if majority of sequences are being generated from “empty” adaptors lacking barcodes).

The analysis was performed in a Jupyter (IPython) notebook and the notebook is linked, and embedded, below.

NBViewer: 20150316_LSU_OilSpill_Adapter_ID.ipynb



Using grep:

15% of the sequences match

That’s about 3% more than when the adaptor and barcode are searched as one sequence.

Using fastx_barcode_splitter:

beginning of line – 17% match

end of line – 0.06% match

The beginning of line matches are ~2% higher than when the adaptor and barcode are searched as one sequence.

Will contact Univ. of Oregon to see if they can shed any light and/or help with the demultiplexing dilemma we have here. Lots of sequence, but how did it get generated if adaptors aren’t present on all of the reads?