How do I get -NH2 or -SH terminated DNA? or How do I introduce amine group at one end of my dsDNA?

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Formaldehyde fixing of nucleosomes resulted in aggregates?

I am trying to fix the nucleosomes by formaldehyde. The idea is to make the nucleosomes stable at high salt concentration and temperature by crosslinking DNA with Histone octamer. We have...

01 February 2019 7,337 4 View

How long can I store nucleosomes at 4degC?

I am imaging nucleosomes using AFM. I purchased nuclesomes from EpiCypher. The storage buffer contains 10mM TrisCl, 1mM EDTA, 25mM NaCl, 2mM DTT, pH 7.5. I have the stock solution (2ug/ul) kept at...

06 July 2018 7,384 3 View

Why does my observation differ from the literature in RBC stiffness measurement?

I am trying to measure stiffness of red blood cells in RPMI using AFM force spectroscopy method. In literature, the typical indentation of RBC at a force of 500pN is 500nm. But in my case I see...

06 July 2018 9,064 6 View

Does APTES react with acetone?

We use APTES for silanization of glass surface. We observed that 4% APTES prepared in acetone turns yellow within 24hours. But the new batch of APTES (Sigma) in acetone is not turning yellow with...

05 June 2018 1,526 3 View

Why does RBC crenate after attaching to glass surface?

I am performing AFM force spectroscopy on red blood cells by immobilizing them on glass surface. I clean the glass coverslips by sonication in soap solution, Milli Q, ethanol, acetone, ethanol for...

02 March 2018 1,337 3 View

How to obtain better images of DNA using AFM?

I am using tapping mode AFM in MilliQ to image a plasmid PGEM3Z which is ~1um long circular DNA. I prepare the sample in the following way. I take 15mm x 15mm mica sheet and cleave it using scotch...

31 December 2017 1,882 4 View

Can we perform PCR with a primer which is thiolated?

I would like to prepared a DNA sample that has -SH or thiol group at one of its end so that I can covalently immobilize it on a surface. The -SH modified primers are commercially available. I am...

11 December 2017 7,381 8 View

Can we image DNA using scanning electron microscope?

I would like to attach DNA to AFM tip and image it using SEM to check if coating was done properly. I couldn't find any papers that show SEM images of DNA. I would like to know the protocol to do...

10 November 2017 6,755 3 View

How do I check if core histones are present in octameric form?

I have purchased human histone octamers from Sigma (SRP0408) for nucleosome reconstitution experiments. I would like to check the protein complex in octameric form. Running it on SDS-PAGE will...

09 October 2017 7,452 7 View

Why do I get negative values in Nanodrop measurements?

I am measuring a sample of histone octamer which is in buffer containing 20mM Tris-HCl, 1mM EDTA, 2M KCl, 10mM DTT, 0.5mM Benzamidine and MilliQ water. I have prepared 1M Benzamidine in Ethanol...

08 September 2017 6,081 8 View

Can I base on reverse DNA sequences to perform alignment, convert to amino acids and GenBank submission?

I have reverse sequences (AB1 format), can I base on reverse DNA sequences to perform nucleotide alignment, convert nucleotides to amino acids and deposit the sequence in GenBank database?

11 August 2024 5,138 1 View

Why Do TDS and EC Increase with Larger Wastewater Volumes, While BOD and COD Decrease?

I have carried out MFC experiments on three different volumes, 50, 500 and 1000 mL of wastewater. Results after MFC treatment shows that TDS and EC are more in larger volumes of water i.e. TDS and...

09 August 2024 9,621 0 View

Could it be a cell culture contamination?

Hello everyone! I observed in my culture (htert-RPE1 cells) an orange- red particle at the bottom of the dish. It is visible to the naked eye as a very very small red dot. Could it be a...

09 August 2024 2,824 3 View

I can't see the ssDNA band after performing asymmetric PCR. Is there any way to do this?

After performing symmetric PCR, PCR purification was performed. Afterwards, asymmetric PCR was performed using the PCR purification product as a template, but no ssDNA band was confirmed in the...

08 August 2024 1,668 3 View

Does crude extraction using NaOH and Tris work well with Fungi?

I'm trying to find a DNA extraction method for fungi that does not require equipment and heating. Is there anyone who can suggest an alternative option? Thank you

08 August 2024 4,733 2 View

Is there any way to quantify bacterial and fungal cells in their mixed culture?

I am working in fungal fermentation of soybean meal and there is bacterial growth in them at times. I am trying to quantify fungal cell counts and bacterial cells; but I haven't been able to do at...

07 August 2024 7,535 4 View

How to normalize and take the significance of the MTT OD values with 3 replicates for the same cell-line?

Hi, I have a question about normalizing the MTT OD values for doing the statistical analysis. So, if we have 3 different plates and we call them 3 different replicates, so, first we would...

07 August 2024 8,106 4 View

Why activated CAR-Jurkat cell could not kill targets?

Previously when I co-coluture anti-CD19(FMC63) CAR-Jurkat with Raji with E:T=5:1, Jurkat can eliminate Raji in 24h. However, when I test another CAR construct, although I can dectect totally CD69...

06 August 2024 641 2 View

Are there instances where molecules with larger molecular weights exhibit greater mobility than those with smaller molecular weights?

Hi, I know that low molecular weight (MW) molecules generally tend to have higher mobility, while high molecular weight molecules tend to have lower mobility. However, in my experimental...

06 August 2024 1,495 2 View

Weak DAPI staining after immunohistochemistry - how to improve?

After immunohistochemistry of previously fixed in PFA and EtOH and then frozen 20 μm sections of zebrafish brain, DAPI staining is very weak (right) compared to the same sections stained without...

05 August 2024 9,637 2 View