BAD BLOOD A strain of E. coli (computer-generated image above) that causes severe diarrhea can latch onto intestinal cells more easily in people with type A blood, a discovery that hints at a potential vaccine.
Alissa Eckert and Jennifer Oosthuizen/CDC
AIR SUPPLY Depriving some cancerous tumors, such as this mouse breast tumor, of oxygen by cutting off blood vessels (red) is one treatment approach. But some oxygen-starved cancer cells (green) can become more aggressive.
Steve Seung-Young Lee/Univ. of Chicago Comprehensive Cancer Center, NCI/NIH, Flickr (CC By-NC 2.0)
HANDY ADD Telomerase (bottom structure), a complex of proteins and RNA, adds DNA to telomeres (green caps), the ends of chromosomes (blue X’s). The telomeres shorten when cells divide.