also it's kinda funny, but me literally working at a child's desk, my own childhood desk, prior to getting the new one, was pinging my impostor syndrome in weird ways lmfao

I don't mean to yammer on about it, it's just a really really good feeling, finally being able to remove a source of debilitating physical pain from my daily routine, that I previously couldn't get around and have been increasingly frustrated with for months

my old desk had been increasingly painful to work at with every passing day, I had to slouch to fit myself into it, and slouching for longer than a few minutes makes the damaged nerve in my shoulder burn and sting so badly that its nigh impossible to think of anything else when its happening. I couldn't take it anymore, and it was a miracle to find a desk this good for so cheap

I like this interface a lot more than Amaroq tbqh

also omfg I can just keep watching YouTube videos, no matter what else is on my screen
I'm watching Tim and Eric Zone Theory while typing rn, this is life changing

I got a Samsung Galaxy S8 and just installed Tusky, and now this is stuck in my head

juni 🦠 boosted
juni 🦠 boosted

bioscience news, The New York Times source 

(this thread is mostly manually reposted from birdsite, because it’s one of few I’ve made recently that I think people might actually find interesting, but I took advantage of Mastodon’s gracious character limit to add more info)

TL;DR the paper expands upon a 2017 paper exploring expression /growth / citrate yield differences in a producer strain given different quantities of iron. Now they’re exploring the same things in conditions of arginine or citrulline supplementation, and making comparisons between the two experiments

And by combining all this RNA seq data and sifting through it in 2 different, complementary ways (a homology-based approach, and a hidden markov model-based approach), they found their exporter

their hypothesis was that, depending on the conditions of the experiment, the accumulation of citrate can be driven by multiple fundamentally different underlying transcriptomic landscapes (I like that expression, no pun intended)

This paper is so cool, and OPEN ACCESS BABY, came out 2 months ago, researchers used a transcriptomic approach to identify a single citrate exporter that the whole phenomenon depends on, and they drew some very interesting conclusions about regulation in the process

Possible reasons "why" include:

the fungus might cope w low iron conditions by releasing tons of citrate to chelate iron from the environment, like a bacterial siderophore

it might use citrate to aid in hydrolysis of sucrose

or citrate might be an overflow metabolite

some clues to “why” may lie in the unusual growth conditions required for maximum citrate production and export: little iron (so little that it limits growth), manganese ions absent, lots of sugar substrate, low pH (<2.6)

The even wilder thing:

There is no unified scientific consensus explaining exactly why it does this, and it's not even fully clear how it does this, though hypotheses have been proposed and various mechanistic elements have been identified

Given the right industrial fermentation conditions, Aspergillus overproduces huge amounts of citric acid. The best producer strains can make 95 kilograms for every 100 kilograms of sugar they're fed, given optimal conditions. That is a LOT of citric acid

...also yes, this implies that you yourself are making citric acid right now, inside your mitochondria, though it’s promptly being converted to cis-aconitate by the enzyme aconitase

But I digress

what’s weird about Aspergillus is just how much citric acid it can accumulate

Citric acid is an intermediate of central metabolism, namely the citric acid cycle, AKA the tricarboxylic acid cycle. Just about every eukaryote (and many prokaryotes) has a TCA cycle

But Aspergillus has a weird trick that makes it stand out

would you like to hear a secret that’s not really a secret

where do you think all the citric acid humans use as a natural preservative, flavoring, acidulant, chelator, and so much more, comes from?

citrus fruits?

nope, try again!

It’s mostly produced by the black mold, Aspergillus niger!

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