Rachel Andrea Chea

9 Questions 15 Answers 0 Followers

Questions related from Rachel Andrea Chea

GDNA stability at 55 degrees?

I was extracting genomic DNA from Streptomyces the previous day and left my gDNA in the oven (55 degrees Celsius) to dry at the very last step. I had to rush off for a seminar and completely...

12 September 2019 9,564 2 View

Difference between pET-28a vector and pET-28b vector?

I'm looking for a pET28 vector with cleavable N-terminal His tag. I noticed there are these two variants (pET28-a and pET-28b). May I know what the difference is between these two?

10 September 2019 7,259 6 View

How does freezing antibiotics result in loss of activity?

I remember my mentor saying before that she decided to refrigerate her gentamycin stock solution instead of freezing it since that was the recommended storage condition. Now, I'm dealing with...

05 August 2019 5,897 4 View

Using 5-FC for plasmid curing - confirmation steps?

To cure my Streptomyces strain of a plasmid, I used 5-FC as a negative selection marker. So, cells without the plasmid (which are the ones I'm looking for) will be able to grow on agar plates...

18 July 2019 5,964 2 View

CRISPR base-editing in bacteria not working?

I am currently using the CRISPR base editing system in bacteria. Unfortunately, I'm not getting any clones with edited bases (not even off-target) but i'm not sure why. I'm quite sure the plasmid...

30 May 2019 8,931 5 View

GDNA stored at -20?

I've extracted my gDNA from Streptomyces today, on a Friday but it's pretty late and I can't stay late today. Is it okay for me to keep my extracted gDNA over the weekends at -20 degrees Celsius...

12 April 2019 3,213 9 View

Volume of ligated product for transformation?

I've just done ligation for my plasmid and my next step would be to perform heatshock transformation on Top10 E. coli cells. Some of my colleagues recommended me to use 2 uL to transform my cells...

02 January 2019 10,075 3 View

Water or kit elution buffer to elute DNA for gel extraction?

I have PCR-ed some DNA samples which I need to perform gel extraction on. These DNA samples will subsequently be used for restriction digestion and ligation over the next week. I was advised to...

19 December 2018 4,139 7 View

Molecular cloning problems?

I've been trying to clone a ~100 bp insert into a ~12000 bp vector backbone. Basically, what I've done is to do the standard things (restriction digestion, PCR cleanup/gel extraction, ligation,...

18 December 2018 1,027 12 View