What is the problem when we can not see anything on agarose jel electrophoresis ?

More Niloufar Mohammadkhani's questions See All

Why am I getting 2 bands of 70 KD and 55 KD for the chains of my antibodies on a SDS-PAGE gel?

Dear All, I have purified 3 variants of the monoclonal antibody from CHO cell line expressing them, using 30 KD amicon ultra-4 centrifugal filter devices following by protein G purification,...

06 July 2019 8,171 13 View

Is it practical to repeat infection process to reach better transduction efficiency?

Dear all, I'm working with lentiviral vectors and aiming to overexpress my gene of interest in CHO-k1 cell lines. I have tried several protocols to reach the high titre of the virus, however the...

04 May 2019 978 4 View

Plasmid transfection in HEK293T cell by Calsium Phosphate method ?

Dear All , we are working on gene transfection by Calcium Phosphate method but after 24h when I want to change the cell culture medium of my test and contro cells , I see that tests are not as...

11 December 2018 3,799 8 View

Which CD20 expressing cell line is better?

Hi there , we are working on antibodies against CD20 antigen ( tositumomab, ofatumumab, Obinutuzumab ) and need a cell line which overexpressing CD20 . as far as I am concerned, Daudi , Ramos...

10 November 2018 7,217 5 View

What is the best protocol for lentivirus transfection in HEK293Tcells by "CaHpo4" ?

Hello everyone , I'm trying to do transfection by lentiviral vectors and my packaging cell line is HEK293T. We are going to do calcium phosphate method.I would like to find the best protocol for...

10 November 2018 4,085 4 View

Generating Stable Cell Lines with Lentivirus ?

Hello everyone We are working with HEK293T cell line. I would like to know which is the best protocol to Generating Stable Cell Lines with Lentivirus(2nd generation) ? any suggestion or comment...

09 October 2018 3,710 2 View

PEI(polyethylenimine) versus CaHpo4 and lipophectamine transfection for virus production in HEK293T cells ?

Hi, I was just wondering if anyone has any personal experience or opinions on using PEI for the production of lentivirus in 293T cells compared to calcium phosphate precipitation and...

09 October 2018 2,421 10 View

Can I use SLA1 instead of XHO1?

Hi there. I want to know is it possible to use SLA1 Enz instead of XHO1? My gene of interest is CD20 And I'm working on PSpax, PMD2G plasmid and PCDH. Any suggestion or comment would be...

08 September 2018 8,816 3 View

Any suggestion or comment in regard of PCR troubleshooting ?

Hi, Here is my PCR Reaction The primers I used were both 10µM. I added 2µl template cDNA and diluted to 10µl total with water. The cycle used was as follows: 95c

07 August 2018 6,897 11 View

PCR troubleshooting.what should I do to solve the problem ?

Hi, I recently ran a PCR Reaction using Taq 2x Master Mix RED - Ampliqon The primers I used were both 10µM. I added 2µl same template human cDNA and diluted to 10µl total with water. The cycle...

07 August 2018 4,270 7 View

How to confirm the site-directed mutagenesis result without performing NGS?

I'm cloning a fragment of 3200 nts into plasmid. The cloning was successful, however, 02 amino acids were mutated. Now I want to fix these 02 aa by site-directed mutagenesis technique using...

08 August 2024 4,645 2 View

Why is my ASO degraded quickly on agarose gel?

I have been working on Red blood cell-derived extracellular vesicles as Antisense Oligonucleotide (ASO) carriers. We normally run agarose gel to quantify the loading efficiency. I used naked ASO...

06 August 2024 3,130 2 View

How can we now if the promotor in the vector is well?

Hi, everyone. I want to transfer two genes in to the pseudomonas bacteria that isolated from the soil. The bacteria that I want to use for cloning haven't been identified and not be sequenced,...

02 August 2024 3,987 1 View

I'm optimizing a tetra-ARMS PCR protocol with amplicon sizes: 165bp, 123bp and 93bp. Why, in the gel, only 165bp is visible while I'm expecting all 3?

It's an end-point PCR protocol. I'm using 1.5% agarose gel with SyBR Safe dye and TBE as a running buffer, visualization on BioRad XR+ system. I was primarily thinking of primer efficiency,...

01 August 2024 4,673 4 View

Illustra™ MicroSpin™ G-25 columns what it is used for?

Hello, We found three packages of Illustra™ MicroSpin™ G-25 columns in the cabinet of an unused lab. They are very old but have never been opened. I have never used this kit before, and I couldn't...

25 July 2024 4,927 3 View

Can I please ask why my samples from anaerobic bioreactor giving me different size PCR product even after multiple runs?

Hi everyone, I have extracted DNA from a biogas bioreactor using Qiagen kit and prep cDNA library then used this library as template to optimize primers for qPCR (taken from papers). Some of the...

23 July 2024 1,329 5 View

Pink bacterial colonies?

I am cloning an overexpression plasmid with my protein of interest tagged with mScarlet. After transforming my ligated product into DH5α bacteria and plating on LB agar, I noticed colonies with a...

22 July 2024 5,953 6 View

Why my gel electrophoresis has smearing?

Greetings. I’m currently running a nested pcr for giardia. My mastermix comprised of 3mM Mgcl2, 5unit of taq polymerase, 0.2uM of forward and reverse primers each respectively and 0.2mM of dNtp...

22 July 2024 9,761 5 View

What are the strategies to Enhance IgG-Producing Plasma Cells in mice for Monoclonal Antibody Development?

I have immunized BalB/C mice with a protein using the intradermal (ID) method with Complete Freund's Adjuvant (CFA) and Incomplete Freund's Adjuvant (IFA), following a 14-day interval and three...

22 July 2024 9,160 2 View

How should we increase the quality of RNA extraction?

I’m having difficulty achieving high RNA integrity in my samples. Although the 260/280 and 260/230 ratios are satisfactory after RNA extraction, the RNA samples show signs of degradation when...

22 July 2024 155 4 View

Pierre Béguin

Hello Nilou,

Did your gel contain ethidium bromide ? If even the markers are not visible, this could be an explanation. Alternatively, you may have switched the power supply with the wrong polarity.

Effendi ..

Agree with Dr. Pierre Beguin.

Alireza Mordadi

please give complete details of your work

there is many reasons

Cliff Philip

Pierre Beguin nailed it, the nucleic acid moved backwards and fell, or there was no stain on the gel..