“The team compiled the first catalogue of all the RNA transcripts expressed in N. viridescens, looking at both primary and regenerated tissue in the heart, limbs and eyes of both embryos and larvae.
The researchers found more than 120,000 RNA transcripts, of which they estimate 15,000 code for proteins. Of those, 826 were unique to the newt. What is more, several of those sequences were expressed at different levels in regenerated tissue than in primary tissue.” Click picture for more.
Stem cells have been used to grow a hormone producing thyroid. This is the first report of that gland being regenerated from stem cells. From Scientific American by way of Nature:
Costagliola and her colleagues first genetically engineered embryonic stem cells to express two proteins — NKX2-1 and PAX8 — that are expressed together only in the thyroid. When these cells were grown in Petri dishes in the presence of thyroid-stimulating hormone, they turned into thyroid cells.
Thyroid cells, however, have to be organized into a particular three-dimensional shape before they can work. They need to form small, spherical follicles containing a cavity in which iodide — a component of some hormones produced in the thyroid gland — can be concentrated before being absorbed and used for hormone synthesis.
Remarkably, the stem-cell-derived thyroid cells spontaneously grouped into follicles similar to those in an intact thyroid gland. And Costagliola and her colleagues found that the follicles were able to trap iodide and synthesize thyroid hormones. “When started the project, our hope was to get some cells that could be used to study thyroid physiology,” says Costagliola. “We never expected to get thyroid follicles.”
Scientists have been hard at work designing artificial muscle that gets activated when exposed to light:
Sakar and colleagues at MIT teamed up with scientists at the University of Pennsylvania to genetically engineer mouse muscle cells that twinge in response to light. The researchers loaded the cells with a light-activated protein, let the cells fuse into fibers, and mixed them with a special gel to form 3-D strips smaller than the width of a grain of rice. Then, they hit the strips with narrow beams of blue light.
Only the light-zapped fibers jumped; those in the dark stayed still. “I was hoping it would work, but the first time I saw it, it was amazing,” Sakar says. “I was very, very excited.”
Sakar and colleagues even got the muscle fibers to show off a bit of brawn. Tissue strips stretched between two tiny elastic posts pulled the structures together when scientists switched on the light.
Read more at Science News. The full report is on line Lab on a Chip. The MIT press release is here with a neat video.