Protein Expression

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Questions related to Protein Expression

Enzyme production and substrate consumtion kinetics of Aspergillus under submerged fermentation?

Hello, I started a few months ago a series of batch and fed-batch fermentations with my isolated strain (Aspergillus) The fermentation conditions that I've followed are biomass formation, pH,...

26 October 2020 4,432 6 View

Can i use Lactose instead of IPTG for M9 protein expression?

Hello all, Is it possible to use lactose instead of IPTG for M9 protein expression? Glucose is traditionally used as the carbon source for labelling proteins and we used 2% final in the media....

15 October 2020 3,795 4 View

What does over foaming correspond to in E.coli fed-batch fermentation?! How does foaming relate to cells metabolic status?

I'm currently experiencing overfoaming in my E.coli culture. My cells are used to produce a recombinant protein. The basic cell strain is BL-21 DE3. After changing my carbon source brand i am...

07 October 2020 4,208 3 View

Inconsistent protein expression for different maxipreps?

I have been having large variability in protein expression from transfections of mammalian cells with DNA from different maxipreps, even though the plasmid is the same. I have been using the...

03 October 2020 3,218 3 View

Will intron-mediated enhancement of gene expression affect downstream of a fusion protein?

Hello everyone! I'm currently trying to increase the expression of my fusion protein in a C. elegans animal model. After reading papers, I found two possible methods to try: (1) codon-optimization...

30 September 2020 679 2 View

Has anyone tried adapting HEK293S GnTI- cells to suspension?

I would like to try protein expression in HEK293S GnTI- cells but in suspension culture. Has anyone tried adapting adherent HEK293S GnTI- to suspension conditions?

23 September 2020 2,215 3 View

Why there is a band around 25Kd of caspase3 in both undifferentiated and differentiated PC12 cells?

Dear all, When I detect the protein expression of caspase3 in PC12 cells, there is always a band around 25Kd. According to literature, the pro-caspase3 should be 35Kd and the cleaved caspase 3...

22 September 2020 8,755 2 View

Is there a technique (aside from immuno-staining) to show that a protein of interest binds filamentous actin? I have not been able to co-IP?

I am confident and reasonably competent with both immuno-staining and co-IP. My immunofluorescent co-staining indicates that my protein of interest does bind the actin cytoskeleton. I have...

19 August 2020 9,536 3 View

Failure of protein expression ?

Dear all, is there any possibility that C-myc epitope tags at recombinant protein can cause the protein degradation/failure in protein expression ? I can't find any previous literature that can...

12 August 2020 7,554 4 View

Does cardiac puncture damage the heart for protein analysis or histological staining?

Hello, we have been sacrificing mice and rats using cardiac puncture. I am curious if anyone knows of publications or has had personal experience relating to potentially altered protein...

01 August 2020 844 2 View

Can I store my BL21-DE3 plate after transformation for a few days at 4℃?

I did a plasmid transformation using BL21-DE3 bacteria yesterday for protein expression, however I couldn't grow them in LB, so I wonder if I can store the BL21-DE3 at 4℃ for one day, or I need to...

16 July 2020 2,427 4 View

Beta Actin levels in different tissues..?

I am seeing the protein expression levels of the control animal group, where I have selected 3 animals, out of which I am checking the protein expression in Muscle, Liver, heart, Adipose,...

24 June 2020 9,633 3 View

Low mRNA expression versus High Protein expression?

I tested gene expression by RT PCR followed by Western blotting to test protein expression. I get an inverse correlation with several proteins (down-regulation at mRNA level and up-regulation...

10 June 2020 7,059 11 View

Mammalian expression: Second codon? Does kozak matter?

I recently saw the paper: "The +4G Site in Kozak Consensus Is Not Related to the Efficiency of Translation Initiation" The +4G Site in Kozak Consensus Is Not Related to the Effici... Which...

03 June 2020 6,146 0 View

Protein expression comparison in different species by Western blot?

Hi, I would like to compare protein expression by Western blot in human testicular germ cell tumor with mouse model of testicular germ cell tumor derived from ectopic transplantation of egg...

31 May 2020 7,847 3 View

No protein expression in Pichia, any ideas?

I introduced a heterologous gene using pPIC 9 plasmid into KM71 strain and confirmed the presence of the target gene by PCR. The colonies (6) I am checking growing well on Minimal growth media...

26 May 2020 1,752 9 View

How to grow more BL21 auxothrophic strain cells?

Dear all, I have just purchased a BL21 auxothrophic strain (RF12) from Addgene. The cells come in the form of agar stab. I intend to grow more cells which will be ready to used for protein...

12 May 2020 8,629 3 View

How can I find the correlation coefficient between 1 categorical variable compared to several other variables?

Let's say that I have 8 proteins: A-H and I have protein expression data for each gene. For each gene, the expression number is based on the average of 20 cell lines expressing that gene. I also...

11 May 2020 3,456 1 View

CHO-K1 and HEK-293 most efficient transfection method?

Hello. I try to transiently transfect CHO-K1 and HEK-293 for protein expression. To estimate ( microscopically ) the efficiency of transfection I use pAcGFP1-N1. I have tried to transfect with...

01 May 2020 9,554 2 View

Are there any accessible servers for optimizing the codon usage of DNA sequences?

Hi, I am trying to do codon optimizing for protein expression in E. coli. I used OPTIMIZER ( http://genomes.urv.es/OPTIMIZER ) before, but the website seems not able to connect now. I was...

19 April 2020 8,211 3 View

Correlation coefficient between gene and protein expression??

How can calculate the correlation coefficient ( r=) after doing ELISA and RT-PCR to confirm the correlation between them

17 April 2020 2,464 4 View

Hi everyone ! can we justify our protein expression results from WB only without performing IHC of same targets on specific tissue???

only WB is sufficient along with mRNA expression to present the data without IHC??

15 April 2020 5,706 4 View

For recombinant protein expression, do I need antibiotics for large culture?

Hi, I am currently using BL21(DE3)PLySs for protein expression. In our lab, we are using selective antibiotics for both inoculation(small culture, a.k.a over night seed culture) and scale up(Large...

07 April 2020 2,792 9 View

Stability of peptides in bacteria?

Hi fellow RGers, in my experiments, I'm trying to express a peptide and I'm curious about the general stability of the expressed peptides. Is there a rule of thumb concerning peptide stability in...

26 March 2020 9,884 3 View

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