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In August 1960, two mongrel dogs named Belka (Little Squirrel) and Strelka (Little Arrow) became the first living creatures to perform a space flight and return safely to Earth.
Spinal cord disorders like spina bifida arise during early development when future spinal cord cells growing in a flat layer fail to roll up into a tube. In the Dec. 6 issue of Nature Cell Biology, researchers from the Johns Hopkins University School of Medicine team with colleagues at the University of California, Berkeley to report a never-before known link between protein transport and mouse spinal cord development, a discovery that opens new doors for research on all spinal defects.
"What I love about this discovery is the total surprise -- we never before would have linked defects in the protein-secretion machinery and neural tube closure," says David Ginty, Ph.D., professor of neuroscience and Howard Hughes Medical Institute investigator.
The team originally set out to find new genes that instruct proper wiring of the hundred billion neurons in the nervous system. To do that, they randomly generated mutations in mouse genes, bred the mice and examined offspring for defects in nervous system development. One of the thousands of mouse embryos examined by graduate student Janna Merte had a spinal cord that had failed to close into a tube. Whereas conditions like spina bifida arise from failure of the tail end of the spinal cord to close, these new mice had a more severe condition, where the entire length of the spinal tube had failed to close.
"What I love about this discovery is the total surprise -- we never before would have linked defects in the protein-secretion machinery and neural tube closure," says David Ginty, Ph.D., professor of neuroscience and Howard Hughes Medical Institute investigator.
The team originally set out to find new genes that instruct proper wiring of the hundred billion neurons in the nervous system. To do that, they randomly generated mutations in mouse genes, bred the mice and examined offspring for defects in nervous system development. One of the thousands of mouse embryos examined by graduate student Janna Merte had a spinal cord that had failed to close into a tube. Whereas conditions like spina bifida arise from failure of the tail end of the spinal cord to close, these new mice had a more severe condition, where the entire length of the spinal tube had failed to close.
© Tracy Tran, David Ginty and Alex KolodkinA pyramidal neuron in the mouse cerebral cortex is labeled using the Golgi technique.
Details of the observation in lab mice, published Dec. 24 in Nature, reveal that semaphorin, a protein found in the developing nervous system that guides filament-like processes, called axons, from nerve cells to their appropriate targets during embryonic life, apparently assumes an entirely different role later on, once axons reach their targets. In postnatal development and adulthood, semaphorins appear to be regulating the creation of synapses -- those connections that chemically link nerve cells.
"With this discovery we're able to understand how semaphorins regulate the number of synapses and their distribution in the part of the brain involved in conscious thought," says David Ginty, Ph.D., a professor in the neuroscience department at the Johns Hopkins University School of Medicine and a Howard Hughes Medical Institute investigator. "It's a major step forward, we believe, in our understanding of the assembly of neural circuits that underlie behavior."
© China Daily
Cao Cao (155-220 A.D.), who built the strongest and most prosperous state during the Three Kingdom period (208-280 A.D.), is remembered for his outstanding military and political talents.
Cao Cao is also known for his poems that reflected his strong character. Some of the poems are included in China's middle school textbooks.
© David A. Aguilar, CfAThis artist's conception shows the newly discovered super-Earth GJ 1214b, which orbits a red dwarf star 40 light-years from our Earth. The planet is thought to be rocky and covered in water.
That promise has proven to be empty, according to Failure to Yield, a report by UCS expert Doug Gurian-Sherman released in March 2009. Despite 20 years of research and 13 years of commercialization, genetic engineering has failed to significantly increase U.S. crop yields.
Versions of this story were published in the Albany Times Union and the Times Herald-Record.
As environmental concerns threaten to derail natural gas drilling projects across the country, the energy industry has developed innovative ways to make it easier to exploit the nation's reserves without polluting air and drinking water.
Energy companies have figured out how to drill wells with fewer toxic chemicals, enclose wastewater so it can't contaminate streams and groundwater, and sharply curb emissions from everything from truck traffic to leaky gas well valves. Some of their techniques also make good business sense because they boost productivity and ultimately save the industry money -- $10,000 per well in some cases.
Yet these environmental safeguards are used only intermittently in the 32 states where natural gas is drilled. The energy industry is exempted from many federal environmental laws, so regulation of this growing industry is left almost entirely to the states, which often recommend, but seldom mandate the use of these techniques. In one Wyoming gas field, for instance, drillers have taken steps to curb emissions, while 100 miles away in the same state, they have not.
As environmental concerns threaten to derail natural gas drilling projects across the country, the energy industry has developed innovative ways to make it easier to exploit the nation's reserves without polluting air and drinking water.
Energy companies have figured out how to drill wells with fewer toxic chemicals, enclose wastewater so it can't contaminate streams and groundwater, and sharply curb emissions from everything from truck traffic to leaky gas well valves. Some of their techniques also make good business sense because they boost productivity and ultimately save the industry money -- $10,000 per well in some cases.
Yet these environmental safeguards are used only intermittently in the 32 states where natural gas is drilled. The energy industry is exempted from many federal environmental laws, so regulation of this growing industry is left almost entirely to the states, which often recommend, but seldom mandate the use of these techniques. In one Wyoming gas field, for instance, drillers have taken steps to curb emissions, while 100 miles away in the same state, they have not.
An Australian astronomer has used ancient culture and modern technology to identify a meteorite crater in central Australia.
Macquarie University PHD candidate Duane Hamacher said on Monday he had spent the past 18 months researching how Aboriginal people have incorporated the night sky into their culture.
He used an Arrernte dreaming story and Google maps to find a crater at Palm Valley, west of Alice Springs, which had been unknown to geologists.
"The particular Western Arrernte story talked about a star that fell from the sky, making a noise like thunder and crashed into a waterhole in Palm Valley," he told Australian Broadcasting Corporation.
Macquarie University PHD candidate Duane Hamacher said on Monday he had spent the past 18 months researching how Aboriginal people have incorporated the night sky into their culture.
He used an Arrernte dreaming story and Google maps to find a crater at Palm Valley, west of Alice Springs, which had been unknown to geologists.
"The particular Western Arrernte story talked about a star that fell from the sky, making a noise like thunder and crashed into a waterhole in Palm Valley," he told Australian Broadcasting Corporation.
© WikipediaLocation of the hippocampus in the human brain. Modified from a scan of a plate of "Posterior and inferior cornua of left lateral ventricle exposed from the side" in Gray's Anatomy.
Their study will be published in the February 2010 issue of Nature Neuroscience and is currently available online.
Neuroscientists often classify human memory into three types: declarative memory, such as storing facts or remembering specific events; procedural memory, such as learning how to play the piano or shoot basketballs; and working memory, a type of short-term storage like remembering a phone number. With this particular study, Strowbridge and Larimer, were interested in identifying the specific circuits that could be responsible for working memory.
