I can't justify staying in this space. This account will be deleted within the next ~48 hours as soon as I have a current backup of my tweets for my personal notes. I'd love to see you on 🦋! Or email me your papers! Or see me IRL!

I don't log in here more than once every 6 months or so - find me elsewheres on the internets.

If you missed hearing about papers - I got you! July special edition #papers365 on Bsky! Username is annikabarber.

Annika is still reading, but mostly board books because she has a new grandbaby and is helping with grand baby #1! Will return to tweeting papers when I'm done with "But Not the Hippopotamus." 🦛

My search terms find all!

Many animals show sleep *loss* during stress, but D. mojavensis sleeps more during nutritional stress and this seems to provide survival advantages. Mechanism TBD, but could be related to waste clearance or energy use. A cool new phenomenon to understand sleep evolution!

But *why* do desert flies sleep more? They turn out to be very resilient to food and food+water deprivation, with elevated sleep time upon nutrient deprivation. Survival during nutrient deprivation was correlated with increased sleep in the Mojave subspecies.

What's different in desert flies? Mass spec analysis found elevated 5-HT and reduced octopamine in mojavensis compared to melanogaster, as well as differences in the number neuroanatomy of PDF+ clock neurons. Injection of wake-promoting octopamine reduced mojavensis sleep.

D. mojavensis has sleep rebound (increased sleep time and intensity) after mechanical deprivation, but unlike melanogaster, shows light-dependent modulation of sleep.

The four D. mojavensis subspecies all sleep more than melanogaster, with elevated sleep pressure, and reduced waking locomotor activity. It's not just because they're recently isolated strains, fresh-caught melanogaster from LA still sleeps less, similar to lab strains.

Desert Drosophila have hard lives...and they sleep more! @party_mcfly_ and not-on-twitter colleagues in the Donlea lab show that D. mojavensis not only sleeps more than melanogaster, they *increase* sleep with food and water deprivation. 🪰🌵doi.org/10.1101/2023.05.27.5…

All this suggests that flies have miRNA regulated tuning of cotransmission in Glu- and GABA-ergic neurons, which may be dynamically regulated by environmental conditions, allowing neurons to rapidly change the magnitude or even sign (Glu & GABA are inhibitory, ACh is excitatory).

Another piece of evidence used a split GFP on VGAT and VAChT, which would only assemble and fluoresce if both transporters were in the same vesicle and there is signal, which increases in older flies (30 days).

Are there situations where ACh would normally be cotransmitted with Glu or GABA? A "translation-trap" experiment that turned on FLP mRNA transcription only when VAChT was transcripts, driving expression of FRT-stop-FRT-EGFP::VGluT and VGAT labeled neurons!

Glu- and GABA-ergic neurons regulates sleep in flies, and expressing the miR-190 sponge in resulted in sleep reduction and fragmentation, showing that there's a behavioral consequence to suddenly cotransmitting ACh with Glu or GABA.

What regulates 3' UTRs? miRNAs, amongst other things, and miR-190 is predicted to bind to the VAChT 3' UTR. Expressing a miR-190 sponge in glutamatergic or GABAergic neurons resulted in expression of VAChT protein!

The authors cleverly notice that the Gal4s don't preserve the native 3' UTR, while the tagged transporters do! Could there be post-trx regulation? Using VGlut or VGAT-Gal4 to flip out a stop cassette for EGFP::VAChT yields no protein signal in adult brains. So possibly yes.

If the Gal4-driven reporters colocalize, and you can do nuclear RNAseq and see that there's VAChT in both glutamatergic and GABAergic neurons, how come you don't get overlap when you actually put the tags onto VGAT & VACht, or VGluT and VAChT? Are they really cotransmitting?

I love a co-transmission mystery story, and @GriffithFlyLab delivers! Gal4 reporters suggest that glutamatergic and gabaergic fly neurons also express acetylcholine. But fluorophore-tagged transporter genes show no overlap...the secret sauce is microRNA. doi.org/10.1126/sciadv.adg98…

Just so y'all know, I also read fiction, and I keep a spreadsheet of that too. Unlike papers, I give everything book a 1-5 rating! 🔥 (Or DNF if it's really bad).