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All posts created by engstrom

| posted 03 Sep, 2024 13:33
Hi Folks,

However, what Eric Engstrom should have written would be "we switched from Fisher Brand Peptone to Bacto Peptone." I should read my notes before posting anything. We did indeed try the agar switch first, but as I review this, that does not appear to have been the fix. The subsequent shift to Bacto Peptone is what saved our bacon.

Heartfelt apologies for disseminating inaccurate information. I was traveling and relying on my memory, rather than my notebook. Never a good idea.

Eric
Posted in: Phage Discovery/IsolationPrecipitation of CaCl2 in PYCA top-agar
| posted 06 Oct, 2023 15:12
Thanks Everyone! We MAY have achieved a breakthrough yesterday by using Millipore water. Haven't run a plaque assay yet, but the appearance of the TA is encouraging. Looks like our DI system may need some maintenance. I'll report on the assays after next week.

Eric
Posted in: Phage Discovery/IsolationPrecipitation of CaCl2 in PYCA top-agar
| posted 05 Oct, 2023 14:52
Hi Community,

We have been stopped in our tracks here at Monmouth, by a very strange issue. Our PYCa top-agar is useless as our CaCl2 is consistently precipitating. We made a new 1M stock of course. We made new dextrose as well. We played with our autoclaving times. And we are not having any trouble with plate agar. At a loss. My question–can we use top-agar for plaque assays if we omit the CaCl2? This would seem to be the quickest route to solving our problem and we will make a test of it soon. Other suggestions?

Thanks!
Posted in: Phage Discovery/IsolationPrecipitation of CaCl2 in PYCA top-agar
| posted 18 Aug, 2023 00:05
Hi Folks,

I am looking at a possible (but I am increasingly thinking unlikely) tRNA in Enygma at roughly 88430-88539. Infernal score is low, but just misses the cutoff at 29.8. Size of the tRNA is within 90 nt, but only just. Aragorn, Aragorn 1.2.38 and tRNAscan-SE all draw different conclusions about the anti-codon. Aragorn 1.2.38 wants to put an intron in, which makes the least sense of anything to my mind. There is no syntenic tRNA annotated at this location in any of the most closely related genomes (Bordeaux, SaltySpitoon, PumpkinSpice). Student annotator took it out. I am leaning toward agreeing, but would value a third opinion.
Posted in: tRNAstRNA enigma in Enygma
| posted 04 Jun, 2023 21:35
I am looking at Stop-8213 in Enygma, a BE cluster phage. HHPred finds significant homology to L7/L12 subunit proteins of the 50S Ribosome in two bacterial species. There is however no detected sequence homology to back this up. Homology occurs across a significant chunk of the Pham, but not its entirety.

aa sequence–MERIEIVQQVGNYFPDTKIADALRFAGDIDRGFARKMEDAQYKAEDEKYEYAEKRYNEGVKAGKESVRTTFDPQVVEATIWATTNFTDRDLTRKITCIKVLRDKFRPLGLIEAKTIMDMIKPLGTTDTLDWPKIVEAEKDSPELATQSALNALRNKLTNNEVARESIDSEESESNDYSTCPCGCGGMA

https://www.rcsb.org/structure/1DD3

I suspect that we need more evidence, but thought it worthwhile enough to post.
Posted in: Request a new function on the SEA-PHAGES official listribosomal protein l7/l12
| posted 13 Apr, 2023 14:41
tRNAScan-SE v 2.0 identifies a Ser tRNA in Huwbert (53324-53234). 90 nucleotides, so a tad big for comfort.

Aragorn v 1.2.41 identifies a Ser tRNA in Huwbert (53233,53324). 92 nucleotides–even worse.

But if we set Aragorn search parameters to allow introns, we instead get a Val tRNA (53233,53324) 88 nucleotides.

We are a bit stuck on 1.) is this a legitimate tRNA call (Triscuit did not call it), and if so, do we allow the intron?
Posted in: tRNAsAllow intron in GG cluster tRNA?
| posted 09 Apr, 2023 14:57
Thanks–that is really quite helpful. We'll leave it a primase/helicase and move along, but I do think that this gene warrants a deep-dive. I'll put it on my list of potential student projects.
Posted in: Functional AnnotationGG cluster DNA primse/helicase
| posted 06 Apr, 2023 22:49
I could use some thoughts on an interesting gene in Huwbert, called stop codon is 58,402. This is syntenic to a Pham called as RecA-like DNA recombinase in Triscuit. But I am not so sure. Nucleotides 335-568/9 find homology to RecA-like recombinases, but only to the AAA-ATPase domain (HHPred). Likewise HHPred picks up other proteins that have an AAA-ATPase in the same stretch. From nt 1-312, there is strong predicted structural homology to Replication Protein B Primase, a function not in the approved function list. Not completely sure where to go with this thing. I could call a DNA primase/helicase, but do I actually have evidence for the helicase function, or just for an AAA-ATPase. A primase would not need an ATPase, so I rather suspect the helicase is there. Anyway, I'd love some feedback. Thanks.
Posted in: Functional AnnotationGG cluster DNA primse/helicase
| posted 07 Apr, 2022 14:29
Hey Folks,

We are experiencing trouble Blasting in DNA Master. When BLASTing all genes, it can run for days with 0% progress. When BLASTing a single gene, we see an error message "HTTP/1.1 403 Forbidden" I have updated DNA Master. Tied ethernet and wireless. I have tried to ensure that our preferences are set correctly, according to the directions in the Bioinformatics Guidelines, but I do not even have a "secure connections" box as an option under PREFERENCES–> Internet. Any ideas would be greatly appreciated.
Posted in: DNA MasterDNAMaster BLAST failure
| posted 28 Feb, 2022 23:13
Hi All,

2/28/22 and I am having a very similar problem. Doesn't look like this issue was resolved earlier. Anyone else unable to update DNAmaster? I am currently running Version 5.22.5 Build 2356. HELP then UPDATE DNA MASTER launches, but ultimately returns a "DNA MASTER failed to update" message.

Thanks anyone who can spot a fix!
Posted in: DNA MasterDNA Master Failing to Update - 01.23.2020