Matt Toomey
@mbtoomey.bsky.social
210 followers 150 following 7 posts
Assistant Professor of biology @utulsa with interests in animal coloration, vision and how carotenoids make the 🌍
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mbtoomey.bsky.social
Happy defrost day 🫠to those who celebrate
mbtoomey.bsky.social
We have a new preprint out! In work led by Rebecca Koch, we investigated red carotenoid metabolism in house finches and find that these birds are likely using a different mechanism than other red bird species.
www.biorxiv.org/content/10.1...
Multiple pathways to red carotenoid coloration: House finches(Haemorhous mexicanus) do not use CYP2J19 to produce red plumage
The carotenoid-based colors of birds are a celebrated example of biological diversity and an important system for the study of evolution. Recently, a two-step mechanism, with the enzymes cytochrome P450 2J19 (CYP2J19) and 3-hydroxybutyrate dehydrogenase 1-like (BDH1L), was described for the biosynthesis of red ketocarotenoids from yellow dietary carotenoids in the retina and plumage of birds. A common assumption has been that all birds with ketocarotenoid-based plumage coloration used this CYP2J19/BDH1L mechanism to produce red feathers. We tested this assumption in house finches ( Haemorhous mexicanus ) by examining the catalytic function of the house finch homologs of these enzymes and tracking their expression in molting birds. We found that CYP2J19 and BDH1L did not catalyze the production of 3-hydroxy-echinenone (3-OH-echinenone), the primary red plumage pigment of house finches, when provided with common dietary carotenoid substrates. Moreover, gene expression analyses revealed little to no expression of CYP2J19 in liver tissue or growing feather follicles, the putative sites of pigment metabolism in molting house finches. Finally, although the hepatic mitochondria of house finches have high concentrations of 3-OH-echinenone, observations using fluorescent markers suggest that both CYP2J19 and BDH1L localize to the endomembrane system rather than the mitochondria. We propose that house finches and other birds that deposit 3-OH-echinenone as their primary red plumage pigment use an alternative enzymatic pathway to produce their characteristic red ketocarotenoid-based coloration. ### Competing Interest Statement The authors have declared no competing interest.
www.biorxiv.org
mbtoomey.bsky.social
We've got a new friend who is very cute!
mbtoomey.bsky.social
Greetings from beautiful Saudi Arabia!
Sunset over sand dunes near Abqaiq
mbtoomey.bsky.social
🦦 Animal #32 🪱
I figured it out in 7 guesses!
🟥🟨🟨🟩🟩🟩🟩
🔥 1 | Avg. Guesses: 7

metazooa.com
#metazooa
mbtoomey.bsky.social
Making friends in Cuervo, NM
Image of a roadrunner