Fear Of Stink: A Century In The Making
Jan22

Fear Of Stink: A Century In The Making

Lurking among us are foolish folks who fork out cash for deodorants even though their armpits don’t smell. This is the take-home message of an article in the Journal of Investigative Dermatology that’s been making the rounds of science news sites and blogs. It’s a fun study, but the results aren’t really that surprising. Researchers have known for years that some people in Europe (2% of the population) and most people in China, Japan, and Korea are fortunate enough to have two copies of a recessive gene that makes their armpits relative* stink-free zones. That’s because the gene codes for a protein involved in transporting molecules out of special sweat glands that appear in your armpits at puberty. These stink-producing glands are called apocrine glands, and they differ from eccrine glands, which are found all over your body and produce the salty fluid we commonly associate with sweat and body temperature regulation. Apocrine glands typically excrete all manner of waxy molecules that armpit bacteria love to feast on. It’s the leftover, metabolized molecules, such as trans-3-methyl-2-hexanoic acid, which give many human bodies that oh-so-ripe odor. Because the difference between stinky and stink-free folks is a gene involved in transporting armpit molecules, it’s pretty likely that people without body odor have a dysfunctional transporter. Although that’s not yet been proven, it’s a reasonable theory. For example, people with odorless armpits also produce a dry white earwax, instead of a yellowish wet version. Presumably, the transport machinery that isn’t exporting bacteria food in the armpit isn’t exporting a yellowish fluid in the ears either. What’s really new in the article is simply the observation that among the 2% of folks in the UK who probably don’t need to apply deodorant, 78% still do. OK, so why is this not really surprising? For one, the UK is dominated by people who have stinky armpits. If you are stink-free, it’s because you have two copies of the recessive, odorless allele of the gene, which behaves in a rather Mendelian fashion, says Ian Day, the University of Bristol researcher who led the study. Being stink-free is rare in the UK, so both parents of an odorless child are probably heterozygous. That means they carry one stinky allele of the gene and one stink-free allele, but they are stinky themselves. Statistically, only one quarter of these parents’ kids will be stink-free. So you can imagine that stinky parents are likely to give their awkward teenagers deodorants in anticipation of that day when their bodies start announcing adulthood. And they probably do it prematurely, so that their teenagers don’t suffer ridicule from other, more well-prepared schoolmates....

Read More
Difficult C. difficile Infections – New Drug, New Targets
Aug31

Difficult C. difficile Infections – New Drug, New Targets

Trust your gut . . . scientifically speaking.  From belly-button bacteria to classification of signature microflora (all the various microbes that populate the intestinal tract), it feels like recent popular “culture” grows best in a petri dish. Many scientists now classify humans as superorganisms, meaning our survival depends on a host of “good” internal bacteria that digest fiber, make vitamins, and help the immune system. But what happens when these good bacteria suddenly get wiped out by a non-selective antibiotic? This sets the stage for a Clostridium difficile intestinal conquest. Simple contact transmits this bacterium between patients in hospitals, causing antibiotic-assisted diarrhea, bloating, and potential colitis. When a patient is treated with a broad-spectrum antibiotic, C. difficile survive by forming spores with tough outer coats, only to thrive again when there are few other bugs in the gut with which to compete. Two new players have recently entered the fight against the difficult C. difficile: first, Optimer Pharmaceuticals’ new narrow-spectrum antibiotic for C. diff. treatment, Dificid (fidaxomicin), approved in May 2011. This antibiotic macrolide belongs to the tiacumicin class of natural products, members of which have been known since Abbott first isolated compounds from fermentation broths in 1987. Dificid specifically inhibits Clostridium RNA polymerase enzymes; without these enzymes, gene transcription halts, and the cells die. Clearing the infection is great, but wouldn’t it be nice to ease the intestinal pain while the drug takes hold? Researchers at UTMB-Galveston might have found a good target for drugs that could do just that. In the August advanced online publications at Nature Medicine, Tor C. Savidge at UTMB-Galveston reports on human metabolites that can inhibit C. difficile toxins TcdA and TcdB, the major agents behind painful antibiotic-assisted diarrhea.  S-nitroso-glutathione, a nitroso (NO)-conjugated version of glutathione found in stool samples of infected patients, can “pass off” its NO group to the sulfur of a specific cystine amino acid residue in the toxins, shutting down their activity. The authors point out that instead of active site binding, the normal mode of action for most enzyme inhibitors, this NO seems to inhibit the toxins via an allosteric site, meaning they bind somewhere else on the toxin but still impair its function. Potency for in vitro inhibition is still in the high micromolar range (43-57 µm), but the study may point the way to the development of more selective NO-transfer...

Read More
Amusing News Aliquots
Aug25

Amusing News Aliquots

Silly samplings from this week's science news. Shrimp on a treadmill: When seemingly silly science catches the eye of a senator. [NPR] We really love the new Nature Chemistry cover (and not just because we’re on it). [Nature Chemistry] Pheromones – awesome for moths, but for people, more of a myth. [Slate] Would the world be richer musically if Mozart had gotten outdoors a little more? [Guardian] Scientists locate lager’s “missing link” - in Patagonia. [LA Times] Do warnings of bacteria in the kitchen avert death or are they overkill? [NY...

Read More