# Storing fruit fly cultures long term



## PanicButton (Jul 8, 2016)

Just came across a study that showed feeding the amino acid proline to fruit Flys allowed researchers to subject them to sub-freezing temps with a 61% survival rate. This was done to try and replicate a sub arctic species of fly's ability to survive being frozen. Proline is available as a dietary supplement so I've ordered some and I'm giving this a shot with a new cultures once they have a good number of all life stages in it. I'm going to test below freezing and above freezing, see what gives me the highest survival rates initially and long term. I figure it could be a nice trick up ones sleeve for those few times in life when poor planning or bad luck lead you to finding yourself with too few cultures, contamination, crashes, etc.. why not right?


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## PanicButton (Jul 8, 2016)

Just read another earlier study where researchers had similar levels of success storing untreated larvae in the 3rd instar long term by alternating temps between 6°C/11°C. These numbers were relative to the larvaes hi/low tolerances for development. Other temperature gradients and stable temps were used but had significantly reduced survival rates. They concluded this was because bringing the larvae just above the threshold for stasis allowed them to rectify some of the chill damage and protein denatrization theyd received from the low temps. Whether proline interferes, compounds, or is unaffected with this effect is unclear. I will expand my test to include treated and untreated cultures with all life stages at:
Short term(1hr) test
-11°C achieved by alternating high-low temps 5°C at a time to target temp.
-11°C achieved by linear drop to target temp.
-11°C achieved by immediate introduction to target temp.

Of these, the highest survival rate will then be applied as the method of introduction into temperatures used in the long term(48hr) test:

-4°C

1°C

6°C

11°C

-6°C/11°C

1°C/11°C

-4°C/11°C

I am only alternating to 11°C because this was concluded in the study mentioned in this post to be the low threshold for the larvae to enter into developmental activity and repair damage so I don't believe alternating to any temp lower than this will produce beneficial results.

It was not made clear by this study neither the interval nor the rate at which each temperature was alternated or achieved, so I will be investigating into that as well once I have narrowed down my variables a bit. 

Turned out to be a bit more comprehensive than I'd originally thought, but what the heck right? I'll have to see if I can hijack the wiring in a mini freezer to reliably hit all those temps otherwise I'll have to bust out the peltiers and Styrofoam to make a chiller. Anyone has any ideas, input, or whatever to chime in, feel free


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