Tag Archives: Pacific oyster

BS-seq Library Prep – C.gigas Larvae OA 1000ppm

Bisulfite Conversion

Pooled 200ng each of the sheared 1B1 (4μL) & 1B2 (used the entire sample, 20μL) 5.13.11 1000ppm C.gigas larvae DNA samples for a total of 400ng. Total volume = 24μL.

Quantified the pooled DNA using the NanoDrop1000 (ThermoFisher) prior to initiating bisulfite conversion.

Clearly, the NanoDrop measurements differ from the expected concentration. NanoDrop suggests the total amount of input DNA is ~1400ng (58ng/μL x 24μL = 1392ng). This is most likely due to RNA carryover, as DNA quantification using a fluorescence-based, double-stranded DNA assay performed previously shows a drastically lower concentration.

Proceeded with bisulfite conversion using the Methylamp DNA Modification Kit (Epigentek) in 1.5mL tube, according to the manufacturer’s protocol:

  • Added 1μL to sample, incubated 10mins @ 37C in water bath
  • Made fresh R1/R2/R3 solution (1.1mL R3 buffer added to vial of R2, vortexed 2mins, 40μL R1 added to mixture – Remainder stored @ -20C in “-20C Kit Components Box”)
  • Added 125μL of R1/R2/R3 solution to sample, incubated 90mins @ 65C in heating block with water
  • Addd 300μL R4 to sample, mixed, transferred to column, spun 12,000RPM 30s
  • Added 200μL R5 to column, spun 12,000RPM 30s
  • Added 50μL R1/ethanol solution to column, incubated 8mins @ RT, spun 12,000RPM 30s
  • Washed column with 200μL of 90% EtOH, spun 12,000RPM 30s; repeated one time.
  • Eluted DNA with 12μL R6, spun 12,000RPM 30s

Quantified post-bisulfite-treated sample on NanoDrop1000:

Definitely a low yield (~108ng) relative to the input (~400ng). Will proceed with Illumina library prep.

 

Library Prep

Illumina library prep was performed with EpiNext Post-Bisulfite DNA Library Preparation Kit (Illumina) (Epigentek).  Changes to the manufacturer’s protocol:

  • Samples were transferred to 1.5mL snap cap tubes for all magnetic bead steps in order to fit in our tube magnets.
  • PCR cycles: 15

No other changes were made to the manufacturer’s protocol.

Epigentek Barcode Indices assigned, per their recommendations for using two libraries for multiplexing (this will be combined with the 400ppm library):

Barcode #12 – CTTGTA

The library was stored @ -20C and will be checked via Bioanalyzer on Monday.

DNA Quantification – C.gigas Larvae 1000ppm

After the discovery that there wasn’t any DNA in the BS-seq Illumina library prep and no DNA in the bisulfite-treated DNA pool, I decided to try to recover any residual DNA left in the 1B2 sample. Sample 1B2 (sheared on 20150109) was dry, so I added 20μL of Buffer EB (Qiagen) to the tube. I vortexed both the 1B1 and 1B2 samples and quantified on the NanoDrop1000 (ThermoFisher). I also re-quantified the pooled BS-treated sample that had been used as input DNA for the libraries.

Results:

Spreadsheet: 20150226_Claire_sheared_Emma_1000ppm_OD260s

Sample 1B1 has ample DNA in it. Since these samples are pools of larvae, we may be able to just proceed with this sample and not worry about pooling with the biological replicate 1B2.

Sample 1B2 has a low amount of DNA, but it’s a usable quantity (total 400ng).

Pooled samples has nothing.

Will make a new pool of DNA from both 1B1 and 1B2 and attempt to make a new bisulfite-treated library.

DNA Quantification – Claire’s Sheared C.gigas Mantle Heat Shock Samples

I previously checked Claire’s sheared DNA on the Bioanalyzer to verify the fragment size and to quantify the samples. Looking at her notebook, her numbers differ greatly from the Bioanalyzer, possibly due to the fact that the DNA1000 assay chip used only measures DNA fragments up to 1000bp in size. If her shearing was incomplete, then there would be DNA fragments larger than 1000bp that wouldn’t have been measured by the Bioanalyzer. So, I decided to quantify the samples on the NanoDrop1000 (ThermoFisher) again.

 

Results:

Spreadsheet: 20150226_Claire_sheared_Emma_1000ppm_OD260s

 

 

 

Comparison of NanoDrop1000 and Bioanalyzer measurements.

Sample NanoDrop (ng/μL) Bioanalyzer (ng/μL)
2M sheared 48.03 16.28
4M sheared 190.96 58.52
6M sheared 141.56 42.98
2MHS sheared 221.93 32.45
4MHS sheared 257.48 43.82
6MHS sheared 202.02 51.12

The NanoDrop is known to overestimate sample quantities due to the indiscriminate nature of UV spectrophotometry and that could be the reason for the large discrepancy between the two measurements (i.e. RNA carryover may lead to overestimation). As such, I’ll quantify the samples using a fluorescence-based assay for double stranded DNA tomorrow in hopes of getting the most accurate measurement.

Bioanalyzer – C.gigas Sheared DNA from 20140108

To complement MBD ChiP-seq data and RNA-seq data that we have from this experiment, we want to generate, at a minimum, some BS-seq data from the same C.gigas individuals used for the other aspects of this experiment.  Claire had previously isolated DNA and sheared the DNA on 20140108. If possible, we’d like to perform MBD enrichment, but the current quantities of DNA may prevent us from this.

To quantify the DNA and evaluate the shearing profile, I ran 1μL of each of the following mantle pre-/post-heat shock samples on a DNA 1000 chip (Agilent) on the Agilent 2100 Bioanalyzer. in the Seeb Lab:

M = mantle
HS = heat shocked

  • 2M sheared
  • 4M sheared
  • 6M sheared
  • 2M HS sheared
  • 4M HS sheared
  • 6M HS sheared

Results:

Bioanalyzer Data File (XAD): 2100_expert_DNA_1000_DE72902486_2015-02-19_11-32-35(2).xad

 

Electropherograms

2100 Bioanalyzer electropherograms of Claire’s sheared C.gigas DNA.

 

Spreadsheet: 2100 expert_DNA 1000_DE72902486_2015-02-19_11-32-35_Results_001

 

Claire’s notebook entry doesn’t ever specify what her target shear size was, but the Bioanalyzer analysis suggests an average size of ~500bp.

Also interesting to note is that Claire’s sample concentrations (as measured on the NanoDrop1000) are significantly greater than what is calculated by the Bioanalyzer. Since the Bioanalyzer chip used (DNA1000) only goes to 1000bp, is it possible the differences in concentrations is due to incomplete shearing of the samples (e.g. a significant portion of the DNA is >1000bp in size and thus not factored in to the Bioanlyzer concentrations calculations)?

Will check sample volumes and determine total amount of remaining DNA for each sample and then assess how to proceed next (i.e. MBD or just BS-seq).

UPDATE 20150226:

Sample volumes were measured and total quantity (ng) of DNA in each sample were added to the spreadsheet above.

Based on the quantities of DNA we have for each sample, will discuss sequencing options (e.g. MBD or not, self-prepare libraries or not, etc) with Steven.

 

Library Prep – Quantification of C.gigas larvae OA 1000ppm library

The completed BS Illumina library made on Friday (1000ppm) was quantified via fluorescence using the Quant-iT DNA BR Kit (Life Technologies/Invitrogen).  Also quantified Jake’s libraries. Used 1μL of  each sample and the standards.  All standards were run in duplicate.  Due to limited sample, the libraries were only processed singularly, without replication.  Fluorescence was measured on a FLx800 plate reader (BioTek), using the Gen5 (BioTek) software for all calculations.

Results:

20150209_CgigasOA_BSlibrraryQuants_OluridaLibraryQuants

The good news is that the standard curve looked fine, with an R²=0.998.

The bad news is that there’s no detectable DNA in the sample, just like last time.

Possibly something is totally shot with this sample?  Will quantify the sheared DNA and decide what to do.

I quantified the sheared DNA and there’s nothing there! Where did it go? I just don’t get it. It was sheared, speed-vac’d and resuspended.  All the DNA should still be in the tubes…

Bisulfite NGS Library Prep – Bisulfite Conversion & Illumina Library Construction of C.gigas larvae DNA

Bisulfite Conversion

The previous attempt at constructing a library for the 1000ppm larvae samples failed. I had previously sheared, quantified, and concentrated the DNA from this sample. As I had done previously, I combined 50ng from each of the two 1000ppm samples for a total of 100ng, and brought the sample volume up to 24μL with NanoPure H2O.

Bisulfite conversion was performed with the Methylamp DNA Modification Kit (Epigentek) according to the manufacturer’s protocol.

Sample was eluted with 10μL of Buffer R6 for immediate use.

 

Library Prep

Bisulfite Illumina library was made with EpiNext Post-Bisulfite DNA Library Preparation Kit (Illumina) (Epigentek).  Changes to the manufacturer’s protocol:

  • Samples were transferred to 1.5mL snap cap tubes for all magnetic bead steps in order to fit in our tube magnets.
  • Skipped Step 7.1 (per manufacturer’s recommendation for samples starting with <200ng)
  • Ran 13 cycles during the library amplification step (per manufacturer’s recommendation for samples starting with 100ng)

Sample was transferred to 1.5mL snap cap tube and stored @ -20C.  Will quantify library on Monday when Jake is also finished with his 12 libraries.

 

Bisuflite NGS Library Prep – C.gigas larvae OA bisulfite library quantification

The two completed BS Illumina libraries (400ppm and 1000ppm) were quantified via fluorescence using the Quant-iT DNA BR Kit (Life Technologies/Invitrogen).  Used 1uL of  each sample and the standards.  All standards were run in triplicate.  Due to limited sample, the two libraries were only processed singularly, without replication.  Fluorescence was measured on a FLx800 plate reader (BioTek).

 

Results:

The standard curve, raw fluorescence, and calculated concentrations (as determined by the Gen5 (BioTek) software) can be seen here: 20150128_CgigasOA_BSlibrraryQuants_OluridaLibraryQuants

The standard curve was excellent, exhibiting a R² value = 0.999

 

Sample Concentration (ng/uL)
400ppm 10.592
1000ppm 0.0

 

The 400ppm library looks great, with a good yield.

The 1000ppm library appears to have no measurable quantity of DNA in it.  This is surprising, and disconcerting, as both samples were processed in parallel.  As such, there should be virtually no difference between them, in regards to the library construction process and subsequent yields.

To verify that this wasn’t a pipetting error on my part, I re-quantified the 1000ppm library (in duplicate) and still no detectable DNA.

Will repeat the bisulfite conversion and library construction process on the 1000ppm sample in order to generate a usable library for sequencing.

Bisuflite NGS Library Prep – C.gigas larvae OA bisulfite DNA (continued from yesterday)

Continued Illumina library prep of bisulfite-treated DNA samples (400ppm and 1000ppm; from 20150114)  with Methylamp DNA Modification Kit (Epigentek). Performed bead clean up immediately after End Repair.

PCR cycles: 14

No other changes were made to the manufacturer’s protocol.

Epigentek Barcode Indices assigned, per their recommendations for using two libraries for multiplexing:

400ppm – barcode #6 – GCCAAT

1000ppm – barcode #12 – CTTGTA

The two libraries were stored @ -20C and will be quantified tomorrow.

 

Bisuflite NGS Library Prep – C.gigas larvae OA bisulfite DNA

The two pooled bisulfite-treated DNA samples (400ppm and 1000ppm) from 20150114 were used to prepare bisulfite Illumina libraries with EpiNext Post-Bisulfite DNA Library Preparation Kit (Illumina) (Epigentek).  Changes to the manufacturer’s protocol:

  • Samples were transferred to 1.5mL snap cap tubes for all magnetic bead steps in order to fit in our tube magnets.
  • Stopped after End Repair step (prior to magnetic bead clean up).  Samples stored @ -20C

DNA Isolation – Claire’s C.gigas Female Gonad for Illumina Bisulfite Sequencing

Due to poor “tag counts” from the initial sequencing (DATE) and the re-sequencing (20131127) of this sample, the HTGU facility has concluded that the library is probably at fault. They will make a new library and do a quality control run on the new library. However, they have insufficient gDNA left to make a new library.

Isolated gDNA from Claire’s sample following the DNAzol protocol.

Transferred ~300uL of female C.gigas gonad from the source tube (ethanol-preserved) to a clean tube. Pelleted gonadal material by spinning 10,000g, 30seconds, @ RT. Decanted residual ethanol. Resuspended tissue in 500uL of DNAzol + 100ug of Proteinase K (Fermentas; 18.5mg/mL). Incubated on a rotator for ~6hrs. Proceeded according to DNAzol protocol. Resuspended final pellet in 100uL of Elution Buffer (Qiagen; EB). After resuspension, pelleted remaining debris 16,000g, 30seconds, @ RT. Transferred supernatant to clean tube and quantified on NanoDrop 1000.

CgF – 403.2ng/uL

Will bring tube to sequencing facility tomorrow morning.