Sunday, July 09, 2017

July 8, 2017

It turns out your skin is crawling with single-celled microorganisms (click here) – ­and they’re not just bacteria. A study by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the Medical University of Graz has found that the skin microbiome also contains archaea, a type of extreme-loving microbe, and that the amount of it varies with age.

The researchers conducted both genetic and chemical analyses of samples collected from human volunteers ranging in age from 1 to 75. They found that archaea (pronounced ar-KEY-uh) were most abundant in subjects younger than 12 and older than 60. Their study has been published in Scientific Reports (a Nature journal) in an article titled, “Human age and skin physiology shape diversity and abundance of Archaea on skin.”

“The skin microbiome is usually dominated by bacteria,” said Hoi-Ying Holman, director of the Berkeley Synchrotron Infrared Structural Biology (BSISB) Programand a senior author on the paper. “Most of the scientific attention has been on bacteria, because it’s easier to detect. Based on the literature, six years ago we didn’t even know that archaea existed on human skin. Now we’ve found they’re part of the core microbiome and are an important player on human skin.”

The study was a joint effort of Holman, Berkeley Lab postdoctoral fellow Giovanni Birarda (now a scientist at Elettra Sincrotrone Trieste in Italy), UC Berkeley postdoctoral fellow Alexander Probst (now associate professor at the University of Duisburg-Essen in Germany), and Christine Moissl-Eichinger, the corresponding author of the study. Moissl-Eichinger and her team at the Medical University of Graz in Austria and at the University of Regensburg in Germany analyzed the genetic features of the skin microbiomes.

In addition to the influence of age, they found that gender was not a factor but that people with dry skin have more archaea. “Archaea might be important for the cleanup process under dry skin conditions,” said Moissl-Eichinger. “The results of our genetic analysis (DNA-based quantitative PCR and next-generation sequencing), together with results obtained from infrared spectroscopy imaging, allowed us to link lower levels of sebum [the oily secretion of sebaceous glands] and thus reduced skin moisture with an increase of archaeal signatures.”...