Krishanu Dey Das

Graduate student @LICB_SMS @bio_iisertvm Working on Golgi dynamics, stress response; 🦋 @kdeydas.bsky.social

[Krishanu Dey Das @kdeydas]

@drkeithsiau Is there any scientific reason to rely on only 95% cut off? I don’t think so, it was decided based on a very early paper if im not wrong. 🤣

[Krishanu Dey Das @kdeydas]

Enhancer? Non coding region? Is there any study regarding that?

[Krishanu Dey Das @kdeydas]

Random thought: Scientists generate stable cell line (OE and KO) using Retro and Lenti virus systems, which integrate randomly in genome and expresses using its own promoters. Does it have any effect on disruption of host chromosome organisation or regulation?

[Krishanu Dey Das @kdeydas]

@rust_ruslan Very clever strategy they have used Tried mito transplant during my Masters time, With centrifugation. Efficiency was very low ~1% 😢

[Krishanu Dey Das @kdeydas]

@rust_ruslan Really beautiful!!! Ought to see if cell can differentiate foreign vs self mito 🤔 MEF mito in Human cell line can it be recognised by human cell, or doesn’t recognise? It will be very interesting!!!

[Nature Reviews Genetics @NatureRevGenet]

New online! Tools and tactics for studying alternative splicing https://t.co/If941K7jWl

[Cell Biology J-Club @cell_club]

Happy Golgi Day

[Rajeev Raghavan @LabRajeev]

At the Open University of the Netherlands @OU_Nederland #Herleen talking about aquatic conservation and governance in southern India!
Thanks to a mobility grant from @uhasselt @MPM_Vanhove @KmentovaNikol

[Poonam Thakur @poonam_thakur6]

Apply for BioTrail – a fully funded Summer Internship Program at @bio_iisertvm for Master’s students in STEM from J&K, Ladakh & the North East!
📅 May–July 2026
📝 Deadline: 10 March 202
Please RT & share with eligible candidates.

[Lori O'Brien @l_obrien_lab]

An old favorite for this #FluorescenceFriday. This "rose" is actually a kidney glomerulus (red, podocytes) and an axon reaching towards it (green).

[IISER Kolkata @iiserkol]

IISER Admissions 2026
IISER Aptitude Test: Sunday, June 7 2026
Application Portal Opens: Thursday, March 5, 2026
More Details: https://t.co/ICFYx0aT7C

@EduMinOfIndia @PIB_India @PTI_News @skkhare781 @priyank_june @IISERAdmissions

[Niko McCarty. @NikoMcCarty]

This paper is wild. After 3 rounds of directed evolution, they converted a DNA polymerase into an enzyme that can do:

- RNA synthesis
- Reverse transcription
- Synthesis of "unnatural" nucleotides
- Synthesis of DNA-RNA chimeras

One of the best papers I’ve read recently.

For context: In nature, it is DNA polymerase that takes a DNA sequence as a template and then copies it. These enzymes are crucial in replicating the genome for cell division, and they are EXTREMELY specific for DNA over RNA. This is key because RNA nucleotides are present in the cell at concentrations ~100x higher than DNA nucleotides, so the enzyme has evolved clever strategies to select one over the other.

RNA polymerases, for comparison, are the enzymes that take a DNA sequence as template and then convert it into RNA. They are involved in gene expression, for example.

To convert a DNA polymerase into an RNA polymerase (and all the other functions I mentioned earlier), the authors did a fairly straightforward directed evolution experiment.

First, they took four DNA polymerase enzymes belonging to various archaea. These DNA polymerases don’t check for DNA vs. RNA as stringently as other types of cells, so they’re a good starting point to evolve RNA polymerases. The authors inserted some targeted mutations into these enzymes, based on known mutations in the literature. For example, they swapped the amino acid at position 409 for a smaller amino acid, thus removing a “gate” that keeps RNA building blocks from entering the enzyme.

Next, they took the four genes encoding these DNA polymerases and cut them up into 12 segments each. They randomly stitched these 12 segments together — from the four different genes — to build millions of unique variants. Each shuffled gene was inserted into an E. coli cell.

Then, they grew up these cells (each carrying a unique polymerase) and put them into microfluidic droplets. A device isolates each droplet, lyses the cell open, and releases the polymerase. The droplet also contains RNA building blocks and a DNA template, encoding a fluorescent reporter. If the polymerase begins synthesizing RNA, it will produce a detectable signal. They screened about 100 million droplets in 10 hours of work, searching for those with a signal.

For each well that yields a fluorescent signal, the researchers isolated the DNA and sequenced it to figure out which polymerase it was. They repeated this 3x times, finally isolating a really excellent RNA polymerase variant which they called "C28."

C28 has 39 mutations compared to the wildtype enzymes. It incorporates about 3.3 nucleotides of RNA per second, with 99.8% fidelity. The crazy thing is that this enzyme can also copy DNA or RNA templates back into DNA (reverse transcription), or use chimeric DNA-RNA molecules as a template and amplify them. It is just a super versatile polymerase that can act on DNA, RNA, or modified nucleotides, to build just about anything.

[Krishanu Dey Das @kdeydas]

@IndianTechGuide 😂😂😂😂

[Krishanu Dey Das @kdeydas]

@MoCA_GoI They are still allowing bookings. Will they fly? 😂 rebook and refund. Cycle continues

[Krishanu Dey Das @kdeydas]

@airindia No cap is being maintained by anyone. @IndiGo6E still allowing to book flights , dont know whether they will again say sorry at the last moment.

[Krishanu Dey Das @kdeydas]

@thevirdas Cancelled all 1000 flights out of 2300 flights. To comply with DGCA guidelines 😂the guidelines were given 8 months ago, still did not bother to comply. Grounding all flights to “reboot” system. I don’t know ehats logical here anymore! @IndiGo6E

[Krishanu Dey Das @kdeydas]

@IndiGo6E Update: CCU-MAA floght is also cancelled. Booked on 8th December now. Same route, @IndiGo6E . They are allowing to book flights, but will they able to deliver? Or again cancellation?

[Krishanu Dey Das @kdeydas]

@IndiGo6E Im not ur wealthy customer 🤞so u may not even notice me. Still saying my pain: I have flight tomorrow from CCU-MAA in evening then a connecting flight from MAA-TVM at 22:30 pm. MAA-TVM flight got cancelled just now. CCU - MAA still showing on time. @IndiGo6E

[Krishanu Dey Das @kdeydas]

@IndiGo6E Not everyone can afford the prices that is going on right now. And being a student it impacts my work, my mental health, and finances also. Hope 8th December, flight takes off from MAA @IndiGo6E and refunding amount is not enough.

[Krishanu Dey Das @kdeydas]

@IndiGo6E We are adjusting, trying . Trains are not available, hotels are expensive, alternative airlines are not available or very expensive due to last minute rush! Just giving a full refund is not enough. @IndiGo6E you value your business, try to respect others time,hard earned money

[Krishanu Dey Das @kdeydas]

@IndiGo6E Still there is no certainty of anything. I booked these flights a month ago. I understand you have some technical/ bureaucratic issues, but i had spent more than 20 k now without any surety. And because of this nonsense issues prices are skyrocketing! @IndiGo6E