I noticed this a day or so ago.
Colorful Mystery Solved: Scientists Discover Enzyme That Makes Urine Yellow
Finding Could Illuminate Future Studies of Gut Health and Inflammatory Bowel Disease
Researchers
at the University of Maryland and National Institutes of Health have identified
the enzyme responsible for giving urine a yellow hue, and it’s more than a
matter of idle curiosity or grade-school giggles.
The microbial enzyme known as bilirubin reductase was introduced in a study
published Wednesday in the journal Nature Microbiology,
paving the way for further research into the gut microbiome’s role in ailments
like jaundice and inflammatory bowel disease.
“It’s remarkable that an everyday biological phenomenon went unexplained for so
long, and our team is excited to be able to explain it,” said lead author
Brantley Hall, an assistant professor in UMD’s Department of Cell Biology and
Molecular Genetics.
When red
blood cells degrade after their six-month lifespan, a bright orange pigment
called bilirubin is produced as a byproduct. Bilirubin is typically secreted
into the gut, where it is destined for excretion but can also be partially
reabsorbed. Excess reabsorption can lead to a buildup of bilirubin in the blood
and can cause jaundice—a condition that leads to the yellowing of the skin and
eyes. Once in the gut, the resident microorganisms can convert bilirubin into
other molecules.
Lots more here:
https://today.umd.edu/colorful-mystery-solved-scientists-discover-enzyme-that-makes-urine-yellow
Reading this I was reminded that 50 years ago I was also interested in bilirubin and its damaging effects on premature neonates. The high bilirubin levels were a marker of an immature metabolism and very high levels often warned of a poor outcome, and a nasty syndrome called kernicterus, which is associated with mental impairment.
I was reminded of this VERY old paper:
Clin Chem 1975 Oct;21(11):1638-43.
Fluorometric determination of "albumin-titratable bilirubin" in the jaundiced neonate
, , , ,
- PMID: 1164793
Abstract
We report a fluorometric technique for determination of albumin-titratable bilirubin in the jaundiced neonate. Although bilirubin alone has very little native fluorescence, considerable emission is observed in the presence of albumin under acid conditions. Analysis of the plasma sample alone and in the presence of excess human serum albumin solution appears to reflect the bilirubin tightly bound to albumin and the total serum bilirubin, respectively. The difference between these two values has been designated as "albumin-titratable bilirubin". Where the concentration of albumin-titratable bilirubin is considerable, a typical saturation effect is observed. In samples where the circulating bilirubin is strongly bound to endogenous albumin, no change in fluorescence is seen when exogenous albumin is added. Results correlate well with the clinical picture.
Here is the link:
https://pubmed.ncbi.nlm.nih.gov/1164793/
In the 50 years since this work was done it really seems that the importance of neonatal jaundice and what to do about it is well established and that has to be a very good thing!
I have had a quick browse to find a current reference site and this looks like a great place to start and to see how things have moved on since I was first interested!
https://www.ncbi.nlm.nih.gov/books/NBK532930/
Neonatal Jaundice
Betty Ansong-Assoku; Sanket D. Shah; Mohammad Adnan; Pratibha A. Ankola.
Author Information and Affiliations
Last Update: February 20, 2023.
Great to see progress really does happen, and from all over! I certainly can’t take any credit!!!!
Hoping Digital Health news ramps up soon!
David.
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