Monday
Jun162014

First 3D molecular model of the presynaptic terminal

B. G. Wilhelm et al., Composition of isolated synaptic boutons reveals the amounts of vesicle trafficking proteins. Science 344, 1023–1028 (2014)

This, in all its molecular complexity, is the first scientifically accurate quantitative 3D model of a synapse. Even if it ‘only’ shows an average terminal without regard for the neurotransmitter it is still breathtaking how the 300,000 synaptic proteins fit into this tiny synaptic bouton and are still organized and fully functioning. This effort has been made possible only by an integrative approach. To create a 3D molecular model of the structure, researchers first isolated the synapses of rat neurons and used quantitative immunoblotting and mass spectrometry to identify and quantify the proteins present at every stage of the neurotransmitter release cycle. Then they turned to electron microscopy to determine organelle numbers, sizes and positions. Finally super-resolution fluorescence microscopy (STED) revealed the location of each protein.

The image is part of an impressive video animation that has been created from obtained data, showing a section of the synaptic bouton, indicating 60 different proteins involved in the neurotransmitter release cycle. (http://news.sciencemag.org/biology/2014/05/video-atomic-view-brain-activity)

The new findings reveal: copy numbers of proteins involved in the same step of synaptic vesicle recycling correlated closely and seemed to be tightly coordinated. In contrast copy numbers of proteins involved in different steps like exocytosis of synaptic vesicles (26,000 copies) and endocytosis of vesicles during recycling (1,000-4,000) differ over more than three orders of magnitude per synapse. Apparently, more than enough proteins are present to ensure vesicle release, but the proteins for vesicle recycling are sufficient for only 7-11% of all vesicles in the synapse. This means that the majority of vesicles in the synapse cannot be used simultaneously. The ultimate goal of the research team led by Prof. Rizzoli “is to reconstruct an entire nerve cell” to create in combination with functional studies a ‘virtual cell’.

Janina Ehses, Master's Thesis Student from Biochemistry department of the Ludwig-Maximilians-University (LMU) in Munich

Monday
Jun162014

Saturated Fat is not bad for you!!!???

Fat. We all have this negative connotation about this word. Whether it’s our diet or appearance we often heard that “fat” is not good for you. Now, a recent study in Cambridge has challenged this idea (at least the dietary side), and the mainstream media has picked it up to state that saturated fat is not bad for you. The review states, "Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.” And if you google saturated fat, there are tons of articles arguing about this subject.

Now we all know nutrition guidelines change ALL THE TIME. One day eggs are bad for you, and now they’re ok. Spinach is good for you, but now not so much. The topic of what’s good and what’s bad changes constantly because new information and new studies are done continuously. But in all honesty, I have a problem with the pop culture’s thinking in the absolute; stating that things are either good or bad. Instead of thinking in black and white, I think we need to focus on balance. A good meal in my opinion consists of veggies, carbs, proteins, and even saturated fat. I think we should stop picking out individual things and labeling them as healthy or unhealthy and just eat a balanced meal. --Also, promoting fat in our diet may not be such a good idea for the obesity epidemic.-- Overall, I think the American diet needs a little more vegetables (potatoes and corn don’t count), and exercise more. 

-Will Takakura, Summer Research Intern

Friday
Jun132014

Just how much does help does nature give us, anyway?

We as humans like to think that our technology and civilization have allowed us to transcend reliance on other forms of life in the natural world. Sure, once upon a time we needed to hunt wild animals and construct shelter from natural materials to make it through the winter, but we’re fine now, thank you very much. The perception is that any plants and animals we need are already part of our agricultural system, and that everything else is just sort of out there, a nice setting for a postcard. This could not be further from the truth.

In the last decade and a half, scientists have been quantifying exactly how much natural ecosystems help us. Each biome provides us with a number of benefits that would be extremely costly to artificially replace. For example, coral reefs (one of the most valuable ecosystems to humans on a per-acre basis) protect coastlines against storms and soften the impact of waves, dramatically reducing soil erosion. Without them, we’d be forced to build expensive seawalls and levees to compensate for the loss of their protection, and pour millions into maintaining defenses that had previously been naturally occurring. A team of scientists has recently published updated calculations on the dollar benefit of “ecosystem services” provided by each biome, and summarized the averages in the graph below. 

            X-axis: US$/hectare/year. (R. de Groot et al., 2012, http://www.sciencedirect.com/science/article/pii/S2212041612000101)

They estimated that the ecosystems they analyzed produce a whopping 142.7 trillion US dollars of ecosystem services every year, roughly twice the GNP of every nation on earth combined. Unfortunately, we have been steadily destroying many of the biomes that contribute to this figure, costing ourselves almost unimaginably in the future via pollution and deforestation. Now that the values of ecosystems are being quantified, the question becomes: do we change our policies in light of the vast financial ramifications? Or will the new dollar sign attached to each ecosystem give us an excuse to stop protecting less “valuable” areas?

~Andrew Wilson, Summer Research Intern

Sources: http://www.nytimes.com/2014/06/05/science/earth/putting-a-price-tag-on-natures-defenses.html?ref=science&_r=1, http://www.sciencedirect.com/science/article/pii/S2212041612000101, http://www.sciencedirect.com/science/article/pii/S0959378014000685

Thursday
Jun122014

Can Dancing Improve your Ability to Remember?

 

A few weeks ago I was on the Green line heading to North Station when I realized that a young woman a few seats away was carrying a pair of tap shoes. My dance background is quite strong, but I haven’t put on my tap shoes in three years. I first started dancing at age three when my mom, some-what frustrated with my high-energy antics, signed me up as a way to tire me out. When I was packing for my summer in Boston, I brought my tap shoes because I knew I wanted to get back into it.

Long story short, I stopped this woman after we got off the train. She recommended a studio for me to look up, and I have been going to tap class once a week ever since.

What surprised me the most about getting back into my shoes was my ability recall dances that I have not seen or performed in years. My dance memory is far better and more accurate than most of my memory. I can even recall dances that I learned for the first time over a decade ago.

Upon investigating the connection between dancers and good long-term memory, I wanted to know what happened in the brain in response to high-intensity dance training and if there were changes in way new long term memories are created or stored. I found that studies have shown that dancers are able to use mental imagery better and with higher reproducibility than non-dancers even in laboratory settings (Blasing et al., 2012). Many areas of the brain are activated during motor learning, included many overlapping areas which could improve devoted concentration and therefore is thought to create a stronger memory. In a case-study, dancers were able to recall dances learned from over three years previously (Steven et al., 2010). The brain function behind long-term kinestetic sequence memory (dance is considered a sequence of steps) is currently not known and is difficult to study. Most studies have focused on ways to disrupt this long-term memory and have not been designed to determine how the disruptions are occurring in the brain, perhaps due to limited tools to study the brains of humans till relatively recently.

Scientists have used both fMRI and PET to study the brains of dancers, but it doesn’t appear that there is much current study using these techniques on long-term dancer memory. Typically, subjects have to remain as still as possible in the large scanners required for these studies. However, a group recently found a way to let ballroom dancers move through the steps with their feet on an inclined apparatus while lying in a PET scan (Blasing et al., 2012). They were able to see activated regions of the brain which were exclusively associated with dancing. This could open the door to more kinesthetic memory based studies using PET and fMRI.

Jaclyn

For more information on what we do know about the brain and dance see: Nerurocognitive Control in Dance Perception and Performance (Blasing et al., 2012)

For more information on dance and long-term memory see: Backwards and Forwards in Space and Time: Recalling Dance Movement from Long-Term Memory (Steven et al., 2010)

 

 

Wednesday
Jun112014

The Power of (Re)-Creation and "Playing God"

As reported in Scientific American last week, undergraduates at John Hopkins University have officially synthesized a yeast chromosome from scratch. According to David Biello, these students synthesized the 272,871 base pairs that make up the essential coding region of the yeast chromosome responsible for sexual reproduction, chromosome 3. The cells that the students grew with the synthetic chromosome appear to be “[thriving] just as well as regular yeast,” at least “in terms of size and growth.”

While David Biello makes a point of elucidating that this is not the first chromosome to be generated from scratch, as a bacterium’s genome was reconstructed by the J. Craig Venter Institute in 2010, it is the first Eukaryotic chromosome to be artificially synthesized.

This achievement should bring to the forefront of ethical debate the considerations regarding the scientific power of creation and “playing god.” Depending on which side of the fence you stand on, this development can either be frightening, or exciting. After all, for the first time in history, scientists have artificially recreated the genetic code in a living eukaryote. How long will it be before we start writing our own variations of genomes? 

~Jack Kent, Summer Research Intern

To read more, please go to the original article as written by David Biello at http://www.scientificamerican.com/article/students-build-the-first-eukaryotic-chromosome-from-scratch/