4.26.2011

Water into wine...Stem cells into neurons


Stable, self-renewing neural stem cells created


Researchers at the University of California, San Diego School of Medicine, the Gladstone Institutes in San Francisco and colleagues have reported the creation of long-term, self-renewing, primitive neural precursor cells from human embryonic stem cells (hESCs) that can be directed to become many types of neurons without increased risk of tumor formation.
To produce the neural stem cells, the researchers added small molecules in a chemically defined culture condition that induces hESCs to become primitive neural precursor cells, but then halts the further differentiation process.
Because the process doesn’t use any gene transfer technologies or exogenous cell products, there’s minimal risk of introducing mutations or outside contamination, the researchers said.
Stained Neuron
Stained mature neurons, derived from precursor cells, expressing the neurotransmitter dopamine (credit: UC San Diego School of Medicine)
The scientists were able to direct the precursor cells to differentiate into different types of mature neurons.  ”You can generate neurons for specific conditions like amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), Parkinson’s disease or, in the case of my particular research area, eye-specific neurons that are lost in macular degeneration, retinitis pigmentosa or glaucoma,” said Kang Zhang, M.D., Ph.D.
The same method can be used to push induced pluripotent stem cells (stem cells artificially derived from adult, differentiated mature cells) to become neural stem cells, Zhang said.

Harvesting water from fog


Fog harvesting for water


MIT researcher Shreerang Chhatre and associates have developed new ways to use “fog harvesting” to provide water to the world’s poor.
A fog-harvesting device consists of a fence-like mesh p anel, which attracts droplets, connected to receptacles into which water drips. To build larger fog harvesters, researchers generally use mesh, rather than a solid surface, because a completely impermeable object creates wind currents that will drag water droplets away from it.
In some field tests, fog harvesters have captured one liter of water (roughly a quart) per one square meter of mesh, per day. Chhatre is conducting laboratory tests to improve the water collection ability of existing meshes.






Mesh being tested for use on fog-harvesting devices (credit: Patrick Gillooly)