Sunday, 22 July 2012

Biology stuff from the week 16-22/7/12

'How altruistic are you?'
A region of the brain called the tempoparietal junction is firmly associated with empathic reasoning.
"The researchers found that those participants who made altruistic choices—such as allocating money to others instead of keeping it—had a higher volume of grey matter, and greater activity, in their TPJ."

The costs of life in micro-gravity:
"A group of three mice have returned alive from a record-breaking 91 days aboard the International Space Station, the longest space trip of any animal besides us. What they experienced can help us understand the effects of long-term space travel on the body. And that might help protect humans in space and back on Earth"
Thyroids, blood, sperm, muscle mass, bone mass - all are negatively affected by life in micro-gravity

'How the same plant species can programme itself to flower at different times in different climates'

Researchers have identified the genetic programme that determines how long vernalization lasts.
Vernalization is the length of time that some plants endure of cold temperatures, before opening up to flower. This mechanism ensures that those plants do not expose themselves before the winter is up, and so hang around for the spring sunshine, when the pollinators will have timed themselves to be available, likewise.
Plants that have to endure longer winters vernalize for longer, and do this by epigenetically weighting a flowering-repressor gene called FLC.
"A combination of four genetic differences (polymorphisms) between the two varieties is responsible for the requirement for a longer period of cold. The polymorphisms affect chemical modifications to histone proteins which DNA is wrapped around. These modifications affect gene expression and are behind epigenetic memory. The four polymorphisms affect these modifications across the FLC gene so this points to how they are able to determine the switching point for the silencing of the gene."

'Human cells, plants, worms and frogs share mechanism for organ placement'
Tubulin proteins are integral to the cytoskeleton of individual cells, but are also responsible for the asymmetrical body-pattern in multi-cellular organisms -- heart and stomach to the left, liver and appendix to the right, etc.
Their part dates back to before eukaryotes diverged into plants and animals. "Tubulin mutations are known to affect the asymmetry of a plant called Arabidopsis"
"In their latest experiment, the Tufts researchers injected the same mutated tubulins into early frog embryos. The resulting tadpoles were normal, except that their internal organs' positions were randomly placed on either the left or right side."

We all know that birds, bees, butterflies, beetles, and people's noses help fertilise flowers; but it was previously believed that mosses copulated passively - with the sperm swimming through a water layer, between the male and female plants.
It's now known that, just as flowers produce scents, mosses stimulate microarthropods (tiny insects) to actively distribute their sperm.

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