White fat or brown fat?

A recent study, published in the journal Cell Metabolism, defines a mechanism that controls if a precursor fat cell matures into a brown fat or white fat cell. Why would this matter?

Most people are undergoing a constant battle to get rid of fat. But, fat cells aren't all the same. Two forms of fat cells exist; white fat and brown fat. White fat is the stuff that stores the excess calories and energy that we taken in, making sure we have enough reserves for lean times when food is scarce. White fat accumulates around the mid-section of our body, along the butt and thighs, and elsewhere. Brown fat is quite different. Brown fat generates heat and burns energy. These cells are filled with energy producing iron-filled mitochondria, hence the brown color, and generates heat for the organism. Brown fat, found mostly in infants (along the spine and shoulders of the back) and hibernating mammals. It's main function is to provide heat to avoid hypothermia in mammals that don't shiver. In adult humans, the amount of brown fat is quite low.

Dr Seale and colleagues have now shown that a protein called early B cell factor-2 or Ebf2 acts like a switch during fat cell development that controls which type of fat cell emerges, a brown fat or white fat cell. It turns out that Ebf2 binds to the promoter of genes involved in brown fat development. This results in the recruitment and binding of another protein, PPAR, and the subsequent expression of these genes. This study also showed that overexpression of Ebf2 in white fat cells converts into brown fat cells. Understanding how these cells develop may help develop new ways to control the amount of white fat cells in the body to help fight obesity.

http://www.alnmag.com/news/how-brown-fat-cells-develop-mice?et_cid=3143363&et_rid=454985655&linkid=http%3a%2f%2fwww.alnmag.com%2fnews%2fhow-brown-fat-cells-develop-mice

New gene controls obesity

The search for an (the) obesity gene has been a long and arduous one that has implicated many candidate genes during this quest. Although these genes that have had important roles in regulating weight, the common thread linking them together has been that have had some role in metabolism and regulating the cell's ability to use energy.

Researchers at the University of Colorado and Tufts Medical School have recently identified another potential regulator of obesity, Plin2. Like previous candidate genes, Plin2 may play a key role in regulating cellular metabolism. Further, the deletion of this gene in mice prevented weight gain, even when the animal was fed a high fat diet. Surprisingly, researchers found that lack of expression of this gene prevented the onset of other obesity associated outcomes -- like high triglycerides and increased inflammation that are seen along with obesity. Even the adipose (fat) cells in these mice were smaller than their paired control mice that faithfully expressed Plin2.

Work is ongoing to learn more about Plin2 and how this gene controls metabolism and weight gain. http://www.scienceomega.com/article/863/removing-gene-stops-obesity-in-mice

Salt activates different receptors depending on concentration

Do you like lots of salt? You may not be alone -- many people love salt. But, even for these salt-lovers, high concentrations of salt taste transitions from delectable to disgusting. How does this happen? We have taste receptors that recognize the sweet, savory, salty, bitter and sour tastes in the foods we ingest. This is an evolutionary adaptation that prevents us from eating potentially deadly or toxic foods. Sweet and savory foods activate one set of receptors and one pathway. On the other hand, sour and bitter foods stimulate a different set of receptors and pathways. This makes sense; different pathways informs us if a food is acceptable or potentially toxic and shouldn't be eaten.

But what about salt? A new paper published in Nature magazine, by Dr. Y. Oka and colleagues (ePub February 13, 2013, print 494: 472), provides new insight into how salty tastes transition from good to bad. At low concentrations, salt activates the savory and sweet pathways, but switches to the bitter and sour pathways at higher levels. Researchers have begun to identify specific receptors that a involved and have shown how blocking these receptors changes the reaction to salt concentrations. This research opens the door to understanding how and why we like salt at times, but not when there is too much of it.

Where have all the postdocs gone, part 2.

Did you "step away from the bench"? What are you doing now and how did you get there?

In recent weeks, I have talked to many scientists about their career tracks away from bench research. We are an intersting bunch. So many have come up with creative ways to use their science background. It really strkes home that having a solid scientific education is very valuable, even if you are not participating directly in science any more.

In a few weeks, I will be talking to science students about careers in science - within academia and outside of it. It would be good to hear how other "alternative career scientists" spend their time. Let me know what you do and how you got there.

Where have all the postdocs gone (aka "alternative careers")?

I heard an interesting statistic that I am not sure is true, but it emphasizes a point. Today at the AAAS annual scientific meeting in Boston, a speaker stated that almost 90% of scientific postdocs are (or will be) looking for alternative careers. Even if that statistic isn't quite accurate, that is a huge number. Where have all the postdocs gone? What are these "alternative careers"? Why are they "alternative" if so many seek them out and pursue them?

I began my own journey to an alternative science career about 2 years ago. Well, in reality it was longer than that, but in earnest, it started two years ago. It has been a great decision and I don't plan on going back, but I don't think the career tracks should be mutually exclusive. Over the coming weeks, I will talk about my journey from academic scientist (as a tenure-track assistant professor) to science policy analyst (for now at least).

Before I start, it's probably good to discuss these "alternative careers" a bit. When I was in graduate school and postdoc training, my colleagues joked that there was only 1 true path for a scientist. Everyone was (and still is to a great extent) expected to follow in the footsteps of their mentor and become an academic researcher. This is a great career and one I pursued for several years. Many aspects of it are incredibly rewarding. For anyone who didn't want to become a professional researcher in medical school or research intensive university, there was little help or guidance provided. To be fair, there are some great mentors that do help their students find a good career option, but the overwhelming advice doled out, however, is that you could work in "industry", whatever that means. Anything that was not a research position with a research lab to run was considered less desirable. All other choices were labeled "alternative" careers in science. Young (and not so young) scientists interested in other career options were cast adrift to explore for themselves. No guidance was available (and sometimes you even dropped of the radar of your mentor as a scientist in their lab - or worse, asked to leave).

The good news is that there are so-called "alternative" careers. There are many of them and many of opportunities. Having a science degree is very beneficial, even if you aren't actively involved in any scientific field or in a way that you imagined when you started to become a scientist. If 90% of postdocs are pursuing alternatives, there are plenty of people out there to tell their story and give advice.

I hope this spurs on some genuine discussion and sharing of success stories. There is a big life away from the bench. I'd like to hear more of them!