As indicated in my first post-holiday post, my flasks mostly still have live cells – although some of the more confluent flasks also resulted in mass cell death. Interestingly, my first thawed flask of cells – with remaining cells maintained after the first passage – still has living cells after four months of continuous culture:

Light microscope image of PHGL TB cells at 13/1/22 showing a main cluster area of remaining cells. 

These cells were originally thawed and plated on 10/09/21. After passage on 21/09/21 the original flask continued to be maintained with a weekly feeding/media change regimen.

Photograph of P1 PHGL TB flask originally plated out by Jo-Maree on 10/0921. 

Light microscope image of P1 PHGL TB cells taken on 21/09/21 prior to passage. 

Light microscope image of P2 PHGL TB cells (in original flask) taken on 23/09/21 after cell passage on 21/09/21. A few cells remain visible in the flask. 

At present, here are only very small clusters of cells remaining:

Light microscope image of P2 PHGL TB cells (in original flask) taken on 13/1/22. The image reveals a ‘sprinkle’ of cells beyond the main cluster. 

The rest of the flask is filled with the ghostly trails of cellular movement:

Light microscope images of P2 PHGL TB cells (in original flask) taken on 13/1/22. The image reveals trails of cellular movement and existence. 

Since this is pretty consistent with prolonged culture, I am curious to show Jo-Maree to determine what the ‘residue’ is. It is quite poetic to consider the way in which  traces remain of different movements and interactions. I have decided to continue to maintain the flask until there are no more viable cells, so it will be interesting to see how these traces evolve.