Sanger Sequencing Data – pCR2.1/Clam RLO clones

Received data from yesterday’s sequencing submission for GENEWIZ order: 10-291940235.  Clones from each of the three groups (16s, EHR, EUB) were sequenced (see below).

Raw sequencing data (.ab1) files were stored on: backupordie/Sequencing Data/Sanger/10-291940235_ab1.zip

  1. SW01 16s_C2_01-M13F(-21)
  2. SW02 16s_C2_02-M13R
  3. SW03 16s_C3_01-M13F(-21)
  4. SW04 16s_C3_02-M13R
  5. SW05 EHR_C2_01-M13F(-21)
  6. SW06 EHR_C2_02-M13R
  7. SW07 EHR_C3_01-M13F(-21)
  8. SW08 EHR_C3_02-M13R
  9. SW09 EUB_C2_01-M13F(-21)
  10. SW10 EUB_C2_02-M13R
  11. SW11 EUB_C3_01-M13F(-21)
  12. SW12 EUB_C3_02-M13R

Sanger Sequencing Submission – pCR2.1/Clam RLO clones

After the previous round of sequencing analysis, decided to sequence a couple of additional clones from each of the three groups: 16s, EHR, EUB. Submitted ~500ng (3μL) of clones #2 & #3 (C2 & C3) from each group to GENEWIZ for Sanger sequencing (Order #: 10-291940235). Each clone was sequenced from each direction with M13F (-21) and M13R primers for a total of 12 sequencing reactions:

  1. SW01 16s_C2_01-M13F(-21)
  2. SW02 16s_C2_02-M13R
  3. SW03 16s_C3_01-M13F(-21)
  4. SW04 16s_C3_02-M13R
  5. SW05 EHR_C2_01-M13F(-21)
  6. SW06 EHR_C2_02-M13R
  7. SW07 EHR_C3_01-M13F(-21)
  8. SW08 EHR_C3_02-M13R
  9. SW09 EUB_C2_01-M13F(-21)
  10. SW10 EUB_C2_02-M13R
  11. SW11 EUB_C3_01-M13F(-21)
  12. SW12 EUB_C3_02-M13R

Sequence Data Analysis – pCR2.1/Clam RLO 16s, EHR, EUB

Sequencing data was received back from GENEWIZ on Friday. The ZIP file containing all six sequence trace files (.ab1) was moved to the lab server:

backupordie/lab/Sequencing Data/Sanger/10-290123409_ab1.zip

The data files were copied to Geneious (v.7.1.7; Biomatters Ltd.) for initial manipulation.

The Geneious files are here (Geneious archive format):

backupordie/lab/Sam/Sequencing_Analysis/Sanger/ireland_clam_RLO/20150309_geneious_Ireland_Clam_RLO.geneious

Quality trimming and vector sequence identification was performed.
All trimmed pairs of files were aligned using the built-in Geneious aligner. Default settings were used, except “Automatically determine sequence direction” box was checked. The alignments were visually inspected for mis-called bases and corrected where necessary. The resulting consensus sequences from each clone were exported to separate files, as well as a single, multi-FASTA file:

backupordie/lab/Sam/Sequencing_Analysis/Sanger/ireland_clam_RLO/Clam_RLO_clones_consensus_20150309.fa

Resulting sequence lengths:

SEQUENCE NAME LENGTH (bp)
 16s_consensus_sequence  1507
 EHR_consensus_sequence  198
 EUB_consensus_sequence 1532

These consensus sequences were aligned to each other using the MUSCLE alignment in Geneious, using default settings (click on images below to enlarge).

Results:

The alignments below show two things:

  1. Similarity (identity) between the sequences being aligned. This is represented as the green bar(s) above the alignments. The more green, the more sequence identity is shared between the two sequences.

  2. The alignments between the two sequences are represented as black bars next to the corresponding sequence name. A black bar/box indicates exact sequence matches between the two sequences. A black line is indicates region(s) where the sequences do not match.

 

16s vs. EHR

Similarity: 11.25%

 

16s vs. EUB

Similarity: 85.18%

 

EHR vs. EUB

Similarity: 12.37%

 

The EHR sequence shares little similarity to the other two sequences.

The 16s & EUB sequences are highly similar, but not identical.

 

Each of the three sequences (using the multi-FASTA file referenced above) was BLAST’d (blastn) against the NCBI nr database.

Results:

16s

The sequence produced using the 16s primers is clearly amplifying the 16s sequence of Vibrio tapetis, a pathogen of cultured clams.

 

EHR

The sequenced captured by the EHR primers has no matches at all in the NCBI nr database. This is likely due to the length of the sequence (only 198bp), however, it’s still long enough that I feel it should match something. Also, just putting this here as a reminder, the EHR primer set is the only set that didn’t produce amplification in the no template controls (NTC).

 

EUB

The product of the EUB primers matches very well to the 16s sequence of a variety of uncultured bacteria species.

 

I will relay the results to Carolyn and see how she’d like to proceed. Due to the nature of what’s being done here (using universal 16s bacterial primers), I think it would be good to sequence additional clones from each of the three cloning reactions to see if we pick up additional sequences.

Plasmid Isolation – Clam RLO 16s, EHR, & EUB clones

Prepared 1x LB + 50μg/mL ampicillin. Aliquoted 5mL of LB-Amp50 liquid media to 18 15mL conical tubes. Used the restreaked plates created 20150207 and used sterile pipette tips to select each of the six positive colonies from each cloning reaction and inoculate 5mL of LB-Amp50 liquid media. Tubes were incubated O/N @ 37C on a rocker.

All cultures grew. Three milliliters from each culture were used to isolate plasmid DNA using the QIAprep Spin Mini Kit (Qiagen). Samples were eluted with 50μL Buffer EB.

Frozen bacterial stocks were made from each of the six clones, using 500μL of each bacterial culture + 500μL of sterile, 50% glycerol in 2mL screw cap tubes.

Bacterial stocks and plasmid preps were labelled in the following fashion:

  • pCR2.1/Clam RLO 16s C1 – C6
  • pCR2.1/Clam RLO EHR C1 – C6
  • pCR2.1/Clam RLO EUB C1 – C6

where “C#” indicates the clone number. The bacterial stocks were stored @ -80C in the following box “Clones Box 2″:

 

Plasmid preps were quantified on the Roberts Lab NanoDrop1000.

Results:

Spreadsheet: 20150305_ClamRLO_miniprep_ODs

After speaking with Carolyn, she decided she wanted to sequence one clone from each group. Submitted ~500ng of clone #1 (C1) from each group to GENEWIZ for Sanger sequencing (Order #: 10-290123409). Each clone was sequenced from each direction with M13F (-21) and M13R primers for a total of 6 sequencing reactions:

1       SW01    16s_01-M13F(-21)
2       SW02    16s_02-M13R
3       SW03    EHR_01-M13F(-21)
4       SW04    EHR_02-M13R
5       SW05    EUB_01-M13F(-21)
6       SW06    EUB_02-M13R

Colony PCRs – Clam RLO 16s, EHR, EUB

Colony PCRs were performed on each of the three transformations from yesterday (16s, EHR, and EUB primers) using the M13F/R vector primers. Colonies were picked form the transformation plates with pipette tips, re-streaked on a secondary, gridded, numbered LBAmp50+x-gal plate and then used to inoculate the respective PCR reactions. Six white colonies (positive clones) and a single blue colony (negative clone) were selected from each transformation.

Restreaked plates were incubated @ 37C O/N and then stored @ 4C (Parafilmed).

Master mix calcs are here: 20150227 – Colony PCR Clam RLO

30μL of each reaction was run on a 1% agarose 1x Low TAE gel, stained w/EtBr.

Results:

Ladder: Hyperladder I (Bioline)

Upper Left: 16s colonies 1 – 7

Upper Right: EHR colonies 1 – 6

Lower Left: EUB colonies 1 – 7

Based on the PCRs used for cloning, all white colonies screened exhibit the expected product sizes. Additionally, each of the blue (negative) colonies, produced the expected band size that are indicative of an empty plasmid.

Will select a positive colony from each set for mini prep and Sanger sequencing.

Cloning – Purified Clam RLO PCRs

Purified PCR products from 16s, EUB, and EHR primers were used for cloning.

The PCR products were separately ligated using the TA Cloning Kit (Invitrogen).

LIGATION

Ligation reactions:

  • PCR product: 4μL
  • 10x Buffer: 1μL
  • Vector (pCR2.1): 2μL
  • Water: 1μL
  • T4 Ligase: 1μL

Incubate O/N (~18hrs) @ 14C.

LB-Amp50 plates from yesterday were used.

TRANSFORMATION

40μL of X-gal (40mg/mL) was added to a LB-Amp50 plate, spread and warmed @ 37C.

Three vials of OneShot TOP 10 chemically competent cells (Invitrogen) were thawed on ice. 3μL of the ligation reaction was added to the cells, gently mixed and incubated on ice for 5mins. 50μL of cells were transferred to the LB-Amp50+X-gal plates, spread and incubated O/N at 37C.

 

PCR – Ireland Clam RLO DNA S/6/14 #19

This is an exact repeat of the PCR from yesterday, but with a brand new vial of Apex Red Master Mix, in an attempt to eliminate the contamination previously seen in the NTCs.

Results:

Ladder: Hyperladder I (Bioline)

Well, for some reason there are still bands in the NTCs. However, they appear to be of different sizes than the bands in the clam DNA samples. I think they’re OK to use and the cloning/sequencing is cheap enough these days, that I’ll just get these sequenced and see what we have.

I excised each of the bands in the clam DNA samples (16s = ~2000bp; EUB = ~2100bp) and purified them using Ultrafree-DA spin columns (Millipore) in preparation for cloning.

PCR – Ireland Clam RLO DNA S/6/14 #19 from 20150130

After the last PCR continued to exhibit products in the no template controls (NTC) for most of the primer sets I was using, I ordered new primers. They arrived today so, I re-ran the PCR on the clam RLO DNA isolated 20150130 with the following new primers:

Master mix calcs are here: 20150223 – cPCR Universal Primers Apex Red MM

Cycling params were:
1 cycle of:

  • 95C – 10mins

40 cycles of:

  • 95C – 15s
  • 50C – 15s
  • 72C – 1min

Samples were run on 1.0% agarose, low TAE gel stained w/EtBr.

Results:

Ladder: Hyperladder I (Bioline).

Crazy; contamination still present in the NTCs. Primer stocks were steriley reconstituted with Low TE Buffer (IDT) and working stocks were created steriley, so I’m not really sure why this is continuing to happen. Possibly the polymerase is contaminated?  Will try again with previously unopened polymerase and see how that plays out.

No bands were excised since I can’t be certain that the bands present in the Clam DNA samples are from the actual sample and not from the apparent contamination.

PCR – Ireland Clam RLO DNA S/6/14 #19 (from 20150130)

After previously confirming that the issue with previous PCRs was due to bad reagents, I re-ran the PCR on the clam RLO DNA isolated 20150130 using a set of universal 16s primers, as well as a universal 18s primer set to serve as a positive control that amplifiable DNA was present in the sample.

Master mix calcs are here: 20150219 – cPCR Universal Primers Apex Red MM

Primers being used are:

  • 16s/23s-F/R
  • 27F, 1492R
  • EHR16D, EHR16R (universal ehrlichia)
  • EUB-A/B
  • 18s EUK 581 F, 18s EUK 1134 R

Cycling params were:
1 cycle of:

  • 95C – 10mins

40 cycles of:

  • 95C – 15s
  • 50C – 15s
  • 72C – 1mins

Samples were run on 1.0% agarose, low TAE gel stained w/EtBr.

Results:

Ladder used was O’GenRuler 100bp DNA Ladder (Thermo-Fisher).

No sample was loaded directly next to ladder to facilitate excision, if necessary.

Each sample was accompanied by a no template control (NTC).

The ehrlichia universal primers (EHR) and the universal 18s (18s) primers are the only two primer sets that do not have contamination present in the NTCs.

Excised the EHR band and purified with Ultrafree-DA columns (Millipore). Purified DNA was stored @ -20C and will be used for cloning/sequencing next week.

Have already ordered additional primer sets of those above that are contaminated. Will re-run the PCR with those new, sterile primer sets when they arrive to obtain a larger product (the EHR amplicon is only ~350bp).

PCR – Universal Primers w/New Master Mix

Since the previous check of the various universal primers with abalone DNA (sample 09:8-20) failed to amplify, even with withering syndrome primers, I’m testing repeating that PCR using a newer/different PCR master mix.

Template DNA is: 09:20-08 (from tissue)

Background info for template DNA is here: Red/Pink/Pinto

Primers being used are:

  • 16s/23s-F/R
  • 27F, 1492R
  • EHR16D, EHR16R (universal ehrlichia)
  • EUB-A/B
  • 18s EUK 581 F, 18s EUK 1134 R
  • WSN1 (withering syndrome)

Master mix calcs are here: 20150212 – cPCR Universal Primers 09:8-20 Apex Red MM

All samples were run in duplicate.

Cycling params were:
1 cycle of:

  • 95C – 10mins

40 cycles of:

  • 95C – 15s
  • 50C – 15s
  • 72C – 2mins

Ran samples out on a 0.8% agarose,  1x TBE gel w/EtBr

Results:

Well, this is a good result.  It demonstrates that the previous reagents that I had been using are no good. The primers work.  However, it does appear that all of the universal primers (excluding the 18s and EHR) are contaminated.  All of these primer sets were stocks that were prepared by other people and none of them were marked as being sterile (which they should be).  Regardless, I’ll re-run the Ireland clam DNA with all the primer sets and see how it turns out.  In the meantime, I’ll also order new universal primer sets to replace the existing, non-sterile sets.