Nitrogen: the chemical fertilizer connection

I’ve been thinking a lot about nitrogen lately. It plays a crucial role in the biosphere because all of the peptide bonds that make up proteins contain that element. And proteins are truly ubiquitous in living things from the very smallest bacteria up to giant redwoods. Because plants require nitrogen to grow, farmers must buy nitrogen containing chemical fertilizers to feed their crops. The run off from their fields pollutes by overloading our waters with nitrogen in the chemical form (called ‘fixed’) found in their fertilizers. The result of that artificial fertilization of lakes and streams (and even coastal estuaries) are algal blooms that crowd out the rest of the biosphere for resources. It’s not good.

Not all crops require fertilizer though. Some crops—legumes—have made a peace pact with the soil microbiome surrounding their roots. In the deal, the local microbes do the work of the farmer by fixing atmospheric nitrogen into the form that plants can use. In return the plants provide other nutrients to the bugs. One of the great challenges for the future of food is to figure out a way to make that peace pact work for our major commercial feed crops like wheat or corn. And that’s not only because it would be a good thing for our waterways. It turns out that chemical fertilizer is also very expensive and requires natural gas to synthesize urea. So if we figured out a way to replicate the microbial pact that legumes have, we could not only reduce pollution, we could save a whole lot of money.

Steven Brill’s book: Tailspin

I am reading it now. I did not realize that he would write about two of my favorite higher education institutions: Amherst College and UC Irvine, both in the context of bridging the moats that currently exclude many (if not most) from the benefits of 21st century American meritocracy. Amherst, because its former President, Anthony Marx, put in place a program to actively reach out beyond the usual legacies and elite high schools in its recruitment of freshman. UC Irvine, because like my own institution (George Mason), it has focused on educating bright students who are from under-represented backgrounds. And by that I mean backgrounds that historically have not had access to the top-flight resources that a UC education is all about. Reason to be a bit optimistic.

On the other hand, Brill really focuses on the legal and financial ecosystems, what he calls the Casino Economy. I wish he also wrote more about scientists and engineers in the same context of the American meritocracy.

How Valium works: in detail

This week, in Nature, the structure of a very important neurotransmitter receptor was revealed. The receptor, the GABA-A, allows the functioning nervous system to avoid the “brain super storms” that constitute epileptic seizures. When the neurotransmitter, GABA, binds to GABA-A, in synapses, in acts to inhibit neural activity. The inhibition of neural activity is critical to brain function because the brain can then compute in a very meta-stable state, quite like a marble on the edge of a saddle. That is one of the key design features of our brains that perhaps can be reverse-engineered someday for more power high performance computing a great energy efficiency.

It’s not surprising then, that the GABA-A receptor is also the target for some key drugs, like Valium and alcohol. Both of these drugs act to inhibit brain activity. When taken together with opioids, the effect is one of synergy and the effects can be deadly.

The paper by Zhu et al. used a technique called cryo-electron microscopy to reveal the detailed structure of GABA-A “frozen in the moment” of binding to a Valium analog. This is very important because it may reveal design hints at how to build a future Valium-like drug that relieves anxiety without sedation.

Humans are naturally curious….

Of course, we know that. And as a scientist, it’s a wonderful thing to get paid to be professionally curious. But too often, scientists and journalists, responding to the siren song of reductionism, act in their own worst interests and over-simplify what is inherently complex. Here is a wonderful piece  by Amanda Ripley on her own experiences with this challenge in the context of the charged political times that we are currently experiencing. I was happily surprised, mid-way through the article, to find my colleague Sara Cobb quoted extensively.

Rules of Life: James Lovelock version

So there are many very naive ways of looking at the Gaia hypothesis–and those have engendered a lot of “antibody-response” over the years from the scientific community. Here, Bruno Latour, the French philosopher lays out Lovelock’s scientific perspective on the biosphere in lay language. I think it’s really quite a good essay–and it would be the proper way to talk about it with a lay stakeholder such as a member of Congress. It reminds me of Harold Morowitz’s views on the subject.

Trees under duress…

I really like trees. When I was coming to the end of my time at NSF, I got interested in the local urban forestry commission. When I see mature trees come down in my neighborhood due to in-fill, I see a distinct loss. Those trees provide shade in the summer and  a nice windbreak in the winter. Trees are also extremely important to the health of the planet because they fix carbon. According to this paper in Nature, they account for approximately 45% of the terrestrial carbon stocks. But the paper is worth reading because it reviews how trees respond to the stress of droughts…of which there are likely to be a lot more in the future. What’s interesting to me is how trees respond to stress through a variety of mechanisms that are truly multidimensional. But…eventually they reach a threshold point where the mechanisms of homeostasis break down and mortality ensues. When this happens, it can be a mass-event with thousands of hectares dying at nearly the same time.