Genes & Cells

Extreme sibling rivalry When conditions get crowded, a type of bacteria called Paenibacillus dendritiformis takes things to an extreme, making a poison to kill encroaching siblings. The poison kills rivals where two groups of bacteria meet. A little back from the edge of the colony the chemical transforms the hot dog–shaped bacteria into little balls impervious to the poison, scientists from the University of Texas at Austin report online May 31 in mBio .  When the round bacteria are in the open, they can transform back into their hot dog shape and swim around. Many other types of bacteria share the genes involved in the transformation and may make similar shape shifts to survive overcrowding . —Tina Hesman Saey

Cell’s breakup cycle
Cellular powerhouses called mitochondria are a little like on-again-off-again sweethearts; they break up and get back together again all the time. The reason the organelles physically split apart and then rejoin wasn’t clear. But now Axel Kowald of Humbolt University in Berlin and Tom Kirkwood of Newcastle University in England propose that mitochondria evolved to get together in order to more efficiently share resources. A destructive side effect of the togetherness is that mutant mitochondria can take over more easily; hence the frequent breakups, the researchers suggest online June 6 in the Proceedings of the National Academy of Sciences. Flaws in the breakup and reunion cycle may lead to aging.  —Tina Hesman Saey

Cells go totally tubular
When cells starve, they start to digest themselves from the inside out in a process called autophagy. But a cell can’t afford to gobble up all of its insides. Now researchers led by Jennifer Lippincott-Schwartz of the National Institutes of Health in Bethesda, Md., show that energy-producing organelles called mitochondria form tubes to keep from being swallowed whole. The researchers report online June 6 in the Proceedings of the National Academy of Sciences that starvation spurs the mitochondria to elongate and fuse together. Tubular formations of mitochondria are spared from cannibalization, perhaps so they can provide some energy to starving cells. —Tina Hesman Saey