Even closely related plants produce their own natural chemical cocktails, each set uniquely adapted to the individual plant's specific habitat. Comparing anti-fungals produced by tobacco and henbane, researchers at the Salk Institute for Biological Studies discovered that only a few mutations in a key enzyme are enough to shift the whole output to an entirely new product mixture. Making fewer changes led to a mixture of henbane and tobacco-specific molecules and even so-called "chemical hybrids," explaining how plants can tinker with their natural chemical factories and adjust their product line to a changing environment without shutting down intracellular chemical factories completely.

Individuals who have a sexually transmitted disease (e.g., genital herpes, gonorrhea, syphilis, and chlamydia) and women with yeast and bacterial vaginal infections have an increased risk of becoming infected with HIV if exposed to the virus through sexual contact. Although several explanations have been proposed, exactly how and why STDs have this effect has not been clear. Now, Teunis B.H. Geijtenbeek and colleagues, at VU University Medical Center, The Netherlands, have described a way in which STDs can increase acquisition of HIV-1 infection in an ex vivo human skin explant model that they hope might be amenable to therapeutic modulation to prevent HIV transmission.