Did I mention Carl Sagan is probably my favorite human? https://www.youtube.com/watch?v=lwL_zi9JNkE&feature=youtube_gdata_player
Decided I’m going to pass the time by building myself a mind palace. Thing is, just for kicks, I’m going to try and construct it as a 5 dimensional hypercube. That it will take awhile is an understatement.
ISS Astronauts Returned Safely to Earth.
“After inspiring all of us on Earth, Commander Chris Hadfield and crew have finally re-joined us here. The Soyuz space capsule landed safely at 10:31 PM EDT in Kazakhstan. Hadfield had spent 144 days on the ISS, 2,336 orbits around the planet and totaled up around 62 million miles. That’s a lot of miles!
The Soyuz capsule landed vertically, which is the preferred position. The crew, which includes Canadian Astronaut Chris Hadfield, NASA astronaut Tom Marshburn and Russian cosmonaut Roman Romanenko, are back on Earth and reportedly all feeling good as they re-adjust to the gravity. Marshburn was one of the astronauts who performed the awe-inspiring emergency spacewalk to fix the leak of ammonia coolant two days ago.
The landing of the capsule comes a little over three hours since the capsule undocked from the ISS. It marks the end of the ISS’ Expedition 35 Crew in space. The crew will head over to the medical tent to get all properly tested and fixed for normal Earth life. Or as normal life can be in the eyes of men who were in space.” via Gizmodo
“On Sunday, Hadfield handed over command of the space station to Russian cosmonaut Pavel Vinogradov.
As part of his personal farewell to the space station, Hadfield released a video of his version of David Bowie’s Space Oddity, which NASA said is the first music video made in space.” via CBC
Serotonin Mediates Exercise-Induced Generation of New Neurons
Mice that exercise in running wheels exhibit increased neurogenesis in the brain. Crucial to this process is serotonin signaling. These are the findings of a study by Dr. Friederike Klempin, Daniel Beis and Dr. Natalia Alenina from the research group led by Professor Michael Bader at the Max Delbrück Center (MDC) Berlin-Buch. Surprisingly, mice lacking brain serotonin due to a genetic mutation exhibited normal baseline neurogenesis. However, in these serotonin-deficient mice, activity-induced proliferation was impaired, and wheel running did not induce increased generation of new neurons. (Journal of Neuroscience, Doi:10.1523/JNEUROSCI.5855-12.2013)*.
Scientists have known for some time that exercise induces neurogenesis in a specific brain region, the hippocampus. However, until this study, the underlying mechanism was not fully understood. The hippocampus plays an important role in learning and in memory and is one of the brain regions where new neurons are generated throughout life.
Serotonin facilitates precursor cell maturation
The researchers demonstrated that mice with the ability to produce serotonin are likely to release more of this hormone during exercise, which in turn increases cell proliferation of precursor cells in the hippocampus. Furthermore, serotonin seems to facilitate the transition of stem to progenitor cells that become neurons in the adult mouse brain.
For Dr. Klempin and Dr. Alenina it was surprising that normal baseline neurogenesis occurs in mice that, due to a genetic mutation, cannot produce serotonin in the brain. However, they noted that some of the stem cells in serotonin-deficient mice either die or fail to become neurons.
Yet, these animals seem to have a mechanism that allows compensation for the deficit, in that progenitor cells, an intermediate stage in the development from a stem cell to a neuron, divide more frequently. According to the researchers, this is to maintain the pool of these cells.
However, the group of wheel-running mice that do not produce serotonin did not exhibit an exercise-induced increase in neurogenesis. The compensatory mechanism failed following running. The researchers concluded: “Serotonin is not necessarily required for baseline generation of new neurons in the adult brain, but is essential for exercise-induced hippocampal neurogenesis.”
Hope for new approaches to treat depression and memory loss in the elderly
Deficiency in serotonin, popularly known as the “molecule of happiness”, has been considered in the context of theories linking major depression to declining neurogenesis in the adult brain. “Our findings could potentially help to develop new approaches to prevent and treat depression as well as age-related decline in learning and memory,” said Dr. Klempin and Dr. Alenina.
Image: In wheel-running mice, the number of proliferating cells (red) that become neurons (green) in the hippocampus is increased, provided they have serotonin (left). In mice that due to a genetic mutation cannot produce serotonin, the number of proliferating cells is not increased following exercise (right). (Photo: Friederike Klempin/ Copyright: MDC)
Canadian astronaut Chris Hadfield's David Bowie cover is an important moment for science
That the viral response to the music video has created a moment where it is seen as advantageous for editors to program more space-related content (including a post like this, I know) is precisely the goal of using media in the ways Hadfield has. He and his team have brought the world a view of space we have never seen in a way we have never seen. With the myriad issues we face in which science plays a role in solving, we need more people to appreciate and admire science and scientists of all types, so making the subject fun and accessible in space is a great way to do it.
Lastly, as Bonnie Malkin at The Telegraph notes “Hadfield will never need to buy a drink on Earth again,” so he’s also got that going for him, which is nice.
Genetics of the Beautiful “Glass Gem” Corn
Corn gone viral? You’re looking at an ear of a corn variety called “Glass Gem”, grown by Greg Schoen of Seeds Trust. This is real corn! How does it grow this way?
First you have to understand a few things about corn. Each corn kernel is actually a sort of unique plant. A corn plant’s male parts (the “tassels”) sit at the top of the stalk, and drop pollen downward. Unfertilized ears (the female parts) catch the pollen with the sticky ends of their corn silks. Each corn silk (I hate when that gets in my teeth) grabs a pollen grain, shuttles it allllllll the way down inside the ear, eventually creating one kernel for each pollen-silk-ovum combination. It’s one of the more interesting and inefficient breeding schemes I know of.
If you’ve taken genetics, you know that the parents’ genes will combine by chance, leading to certain ratios of inheritance in the offspring. This is the basis of Mendelian genetics (great Khan Academy video here).
With corn, we’ve simply carefully bred all the interestingness out of them. Native Americans were used to multi-colored corn, because corn plants held many varieties of color genes that could combine at random. Now all we are left with are one-color clones.
This “Glass Gem” corn is the other extreme of the spectrum, a combination of corn color hybrid genes and random pollination. It’s almost too pretty to eat!
(via Discover Magazine)
Out of sync with the world: Body clocks of depressed people are altered at cell level
Finding of disrupted brain gene orchestration gives first direct evidence of circadian rhythm changes in depressed brains, opens door to better treatment
Every cell in our bodies runs on a 24-hour clock, tuned to the night-day, light-dark cycles that have ruled us since the dawn of humanity. The brain acts as timekeeper, keeping the cellular clock in sync with the outside world so that it can govern our appetites, sleep, moods and much more.
But new research shows that the clock may be broken in the brains of people with depression — even at the level of the gene activity inside their brain cells.
It’s the first direct evidence of altered circadian rhythms in the brain of people with depression, and shows that they operate out of sync with the usual ingrained daily cycle. The findings, in the Proceedings of the National Academy of Sciences, come from scientists from the University of Michigan Medical School and other institutions.
The discovery was made by sifting through massive amounts of data gleaned from donated brains of depressed and non-depressed people. With further research, the findings could lead to more precise diagnosis and treatment for a condition that affects more than 350 million people worldwide.
What’s more, the research also reveals a previously unknown daily rhythm to the activity of many genes across many areas of the brain – expanding the sense of how crucial our master clock is.
In a normal brain, the pattern of gene activity at a given time of the day is so distinctive that the authors could use it to accurately estimate the hour of death of the brain donor, suggesting that studying this “stopped clock” could conceivably be useful in forensics. By contrast, in severely depressed patients, the circadian clock was so disrupted that a patient’s “day” pattern of gene activity could look like a “night” pattern — and vice versa.
The work was funded in large part by the Pritzker Neuropsychiatric Disorders Research Fund, and involved researchers from the University of Michigan, University of California’s Irvine and Davis campuses, Weill Cornell Medical College, the Hudson Alpha Institute for Biotechnology, and Stanford University.
The team uses material from donated brains obtained shortly after death, along with extensive clinical information about the individual. Numerous regions of each brain are dissected by hand or even with lasers that can capture more specialized cell types, then analyzed to measure gene activity. The resulting flood of information is picked apart with advanced data-mining tools.
Lead author Jun Li, Ph.D., an assistant professor in the U-M Department of Human Genetics, describes how this approach allowed the team to accurately back-predict the hour of the day when each non-depressed individual died – literally plotting them out on a 24-hour clock by noting which genes were active at the time they died. They looked at 12,000 gene transcripts isolated from six regions of 55 brains from people who did not have depression.
This provided a detailed understanding of how gene activity varied throughout the day in the brain regions studied. But when the team tried to do the same in the brains of 34 depressed individuals, the gene activity was off by hours. The cells looked as if it were an entirely different time of day.
“There really was a moment of discovery,” says Li, who led the analysis of the massive amount of data generated by the rest of the team and is a research assistant professor in U-M’s Department of Computational Medicine at Bioinformatics. “It was when we realized that many of the genes that show 24-hour cycles in the normal individuals were well-known circadian rhythm genes – and when we saw that the people with depression were not synchronized to the usual solar day in terms of this gene activity. It’s as if they were living in a different time zone than the one they died in.”
Huda Akil, Ph.D., the co-director of the U-M Molecular & Behavioral Neuroscience Institute and co-director of the U-M site of the Pritzker Neuropsychiatric Disorders Research Consortium, notes that the findings go beyond previous research on circadian rhythms, using animals or human skin cells, which were more easily accessible than human brain tissues.
“Hundreds of new genes that are very sensitive to circadian rhythms emerged from this research — not just the primary clock genes that have been studied in animals or cell cultures, but other genes whose activity rises and falls throughout the day,” she says. “We were truly able to watch the daily rhythm play out in a symphony of biological activity, by studying where the clock had stopped at the time of death. And then, in depressed people, we could see how this was disrupted.”
Now, she adds, scientists must use this information to help find new ways to predict depression, fine-tune treatment for each depressed patient, and even find new medications or other types of treatment to develop and test. One possibility, she notes, could be to identify biomarkers for depression – telltale molecules that can be detected in blood, skin or hair.
And, the challenge of determining why the circadian clock is altered in depression still remains. “We can only glimpse the possibility that the disruption seen in depression may have more than one cause. We need to learn more about whether something in the nature of the clock itself is affected, because if you could fix the clock you might be able to help people get better,” Akil notes.
The team continues to mine their data for new findings, and to probe additional brains as they are donated and dissected. The high quality of the brains, and the data gathered about how their donors lived and died, is essential to the project, Akil says. Even the pH level of the tissue, which can be affected by the dying process and the time between death and freezing tissue for research, can affect the results. The team also will have access to blood and hair samples from new donors.
Image:The researchers used gene expression patterns to try to predict the time of death for each person in the study (inner circles), and then compared it with the actual time of death (outer circles). The two matched closely in healthy people, as shown by the short lines between the two points in the left diagram. But in depressed people, the two were out of sync, as seen at right. Credit: University of Michigan.
