Nicolle Rager Fuller
Boons and busts via gut microbes
Studying the secret lives of bacteria living in human intestines has yielded some unexpected finds. One study suggests that most humans have one of three different combinations of friendly microbes (SN: 5/21/11, p. 14), and another reveals that people’s mix of microbes depends heavily on diet. Changing the ratios of nutrients consumed tweaks the composition of the microbial populations in the guts of mice carrying human bacteria, scientists find (SN Online: 5/19/11).
Knowing just how to alter the diet to achieve the right mix of microbes may be important for good health, both physical and mental. At least one type of friendly bacteria can send signals from the intestines through the vagus nerve in the neck to influence brain chemistry and change behavior in mice, researchers report (SN: 10/8/11, p. 9). Gut microbes have also been found to convert a type of fat found in meat and dairy products into an artery-clogging chemical, and intestinal microbes may trigger multiple sclerosis, an immune system disorder in which the body attacks its own nerve cells (SN: 12/3/11, p. 11).
But even if some bacteria break hearts or turn a body against itself, organisms of all sorts would be in big trouble without them. Mice given antibiotics that kill off their microbes can’t fight the flu as well mice that don’t take the drugs (SN: 4/9/11, p. 14). —Tina Hesman Saey
Bright cats Kittens are engineered with a gene for an antiviral protein that scientists hope will help combat feline immunodeficiency virus (SN: 10/22/11, p. 9). The cats also get a gene that makes them glow.
Beneficial liaisons Humans may have acquired important immune system genes via liaisons with extinct hominid cousins, the Neandertals and Denisovans (SN: 10/8/11, p. 13).
Healthy aging After mining the DNA of a woman who lived to age 115, researchers conclude that she did not lack genetic variants predisposing her to heart disease and other aging-related illnesses (SN: 11/5/11, p. 9).
Genetic loophole The occasional switch of a chemical unit in RNA to a slightly different form can cause a cell’s protein-building machinery to roll right through a molecular stop sign, a find that violates the central dogma of genetics (SN: 7/16/11, p. 8).
More than squirm A new system, named COLBERT for “Controlling Locomotion and Behavior in Real Time,” allows researchers to commandeer tiny worms and pick apart behavior cell by cell (SN: 2/12/11, p. 14).
Missing DNA, bigger brains Humans may have developed bigger brains, spineless penises and other traits after losing 510 chunks of DNA, a study suggests (SN: 4/9/11, p. 15).
Gene fix A new gene therapy allows direct fixing of DNA. With molecular editors called zinc finger nucleases, scientists correct a mutation in mice that leads to hemophilia (SN: 7/30/11, p. 9).
Superbug from drugs Antibiotics and vaccines helped shape the evolution of a nasty strain of pneumonia-causing bacteria, scientists find (SN: 2/26/11, p. 16).
Lager mystery Scientists identify a missing ancestor of yeast used in cold-brewed beer (SN: 9/24/11, p. 16).
Stem cell steps The body’s immune system may attack lab-made stem cells, a study in mice finds, a possible hurdle to using such cells to replace damaged tissue (SN: 6/4/11, p. 13). Another study uses human eggs to reprogram adult cells to a primitive embryonic-like state, but they have extra chromosome sets (SN: 11/5/11, p. 8).
Burn that fat Mice lacking a protein that responds to the hunger-promoting hormone ghrelin burn more energy in their brown fat than other mice, hinting at a way to fight obesity (SN: 1/15/11, p. 9).
To the heart With a little help from cellular reprogramming factors, skin cells are converted into beating heart cells (SN: 2/26/11, p. 16). With some prodding, stem cells lining the outside of the heart can also form new heart cells (SN: 7/16/11, p. 9).
Pylori trouble A bacterial bad guy responsible for causing ulcers and stomach cancer, Helicobacter pylori, may help trigger Parkinson’s disease (SN: 6/18/11, p. 18).
Brain healing Blocking newborn nerve cell formation in mice prevents the animals from learning and remembering in a maze after brain injury, suggesting the newborn cells may help the brain heal (SN: 4/23/11, p. 10).
Gland growth Japanese researchers grow for the first time a mouse pituitary gland from embryonic stem cells in a lab dish, a first step toward replacement glands for people (SN: 12/31/11, p. 15).
Electric eye Cells in a tadpole’s gut manipulated to take on specific electrical properties develop into an eye, a major advance toward regenerating complex organs and limbs (SN: 12/31/11, p. 5).