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Science Notes / Aquaculture and biology

Salmon issue sizzles

The Food and Drug Administration's public comment period for labeling requirements for a genetically engineered salmon ended not so quietly, with a flurry of press releases leading up to the deadline.

They included an announcement by a group of lawmakers from Alaska and the Northwest of legislation that would prohibit FDA approval of a GE salmon, or require that it be labeled as genetically engineered in the event regulators approved the fish.

A letter from a dozen environmental, science and consumer groups urged FDA Commissioner Margaret Hamburg to look carefully at possible adverse ecological consequences as it evaluates a Massachusetts firm's application for a GE salmon for human consumption. It would be the first GE food animal.

AquaBounty Technologies' AquAdvantage salmon reaches market weight in about half the time of a regular North Atlantic salmon. Opponents fear the fish could escape confinement, and they lean heavily on perhaps the most hotly disputed evidence in the GE salmon debate -- the so-called Trojan gene effect, in which a specific genetic advantage enables it to outcompete unaltered salmon, leading to their demise. Supporters counter that the size advantage is only temporary, and that the full-size salmon seem to be lousy at mating.

-- Los Angeles Times


The physiology of fear

Fear is a complicated emotion, and scientists have recruited a scary laboratory aide to map out how the feeling is processed in the brain: the Brazilian salmon pink tarantula.

Using video of the 8.7-inch-long arachnid, British researchers showed that the brain engages several different systems when evaluating threats. For instance, the part of the brain that engages when a threat is approaching is different than the part that is activated when a threat is receding, they reported.

The researchers chose a spider species for their test because the creepy-crawlies are responsible for one of the most common phobias in human beings, said Dean Mobbs, the study's lead author and an affective neuroscientist at the Cognition and Brain Sciences Unit at the Medical Research Council in Cambridge, England.

The researchers placed volunteers in a functional MRI machine to watch which parts of their brains were activated during different stages of the experiment. Each volunteer was asked to place a shoeless foot into a box that was connected to a row of five other boxes, and were shown videos of the tarantula entering the boxes.

As the video spider advanced toward people's feet -- unknown to them, no tarantulas actually were present -- the volunteers' brains switched from anxiety to panic. In addition, as the tarantula appeared to recede, the MRI machine registered increased activity in the orbitofrontal cortex. Mobbs said this area might emit a "safety" signal that dispels the fear signal.

-- Los Angeles Times

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