Results tagged “bacteria” from Jessica Snyder Sachs, Science Writer

Women's Hands More Microbially Diverse


You may have seen or heard the recent headlines, along the lines of "Women's Hands 'Germier' than Men's." The report behind the rather misleading news flash is more interesting.

University of Colorado professor Noah Fierer studies the ecology of bacteria, fungi, and related microbes in natural systems such as soil, water, and the atmosphere. Turning his survey techniques to the human body, he looked at the diversity of bacteria on the hands of 51 students--all healthy except for the interesting twist that they'd all just finished their final exams. (Sweatier palms than usual, perhaps?)

Fierer and his colleagues used a gene-sequencing technique to count the number of different types of bacteria on each subject's hands. They tallied an impressive 4,742 types.

The quirky news headlines jumped out of the unexpected finding that the hands of female students harbored a greater diversity (but not necessarily more germs, per se) than did the guys'. 

Just as interesting, perhaps, was the finding that while everyone seemed to share a core group of common skin bacteria, these common species made up just 13 percent of the total diversity. In fact, over 80 percent of the microbial species found on a person's left hand were different from those found on the right.

All this seems to suggest that most of the bacteria on our hands are fleeting transients. We pick them up as we touch objects, surfaces, and other body parts.

That said, the researchers found that hand washing--while a good idea when you're around others who might be ill--did little to change the diversity of the a palm's rainforest-rich ecosystem.

Hre's the study, in the Proceedings of the National Academy of Sciences, with more interesting stuff at Fierer's website at the University of Colorado.

Bacterial Mouth Magic

Wine-Romance-byLizLyonsFriedman.jpgI've long been intrigued by the idea that we have bacteria to thank for human pheromones, or "sex scents." Even the sweatiest human underarms remain odorless until skin bacteria process the sweat into the odiferous  steroids that will arouse those inclined toward your gender.

(linocut by Liz Lyons Friedman)

Now Swiss biochemists say we can thank our microflora for another inherently pleasurable odor--that of good food and drink.

Scientists at Firmenich, a Geneva-based producer of flavor and perfume chemicals found that mouth bacteria produce the lingering "retro-aromas" we enjoy after swallowing food and drink containing fruits such as grapes and vegetables such as onions and sweet peppers. Specifically, they found that anaerobic mouth bacteria transform odorless sulfur compounds into odor-rich thiols. Your saliva traps the thiols in a way that allows you to savor. Their study is in this month's issue of the Journal of Agricultural and Food Chemistry.

So just maybe, before your next romantic dinner, consider a mutual agreement to lay off the antibacterial mouthwash and at least dial back on the deodorant--for maximum enjoyment of the food, wine, and company.