MIT finds new role for well-known protein

Research could lead to treatments for Alzheimer's, Parkinson's,

Fluorescent micrograph (scale bar: 10 micrometers) shows yeast cells (red) with septin (green), which enables the budding of daughter cells. MIT researchers have found septin also helps neurons sprout the branch-like protrusions used to communicate with other neurons. Image / Philippsen Lab, Biozentrum B

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In a finding that may lead to potential new treatments for diseases such as Alzheimer's and Parkinson's, researchers at the Picower Institute for Learning and Memory at MIT report an unexpected role in the brain for a well-known protein.

A study by Morgan H. Sheng, Menicon Professor of Neuroscience and a Howard Hughes Medical Institute investigator, and colleagues appearing in the Oct. 23 issue of Current Biology shows that the same protein that enables a yeast cell to bud into two daughter cells also helps neurons sprout the branch-like protrusions used to communicate with other neurons.

The work revolves around septins--proteins known since the 1970s to play an essential function in the process through which the cytoplasm of a single yeast cell divides. "In yeast, septin is localized exactly at the neck between the yeast mother cell and the bud or emerging daughter cell," Sheng said. "Amazingly, we found septin protein localized at the base of the neck of neuronal dendritic spines and at the branchpoint of dendritic branches."

Nine of the 14 septins found in mammals are found in the brain. One of them, Sept7, appears the most, but its role was unclear. Septins form long filaments and act as scaffolds, recruiting other proteins into their assigned roles of builders of the cell infrastructure.

While neurons don't divide, they do form protrusions that eventually elongate into dendritic branches. Dendrites, from the Greek word for "tree," conduct electrical stimulation from other neurons to the cell body of the neuron from which the dendrites project.

Electrical stimulation is transmitted via synapses, which are located at various points along the dendritic branches. Dendrites play a critical role in receiving these synaptic inputs. "Because dendritic spines are important for synaptic function and memory formation, understanding of septins may help to prevent the loss of spines and synapses that accompanies many neurodegenerative diseases," said co-author Tomoko Tada, a postdoctoral associate in the Picower Institute. "Septin could be a potential target protein to treat these diseases."

Moreover, in the cultured hippocampal neurons the researchers used in the study, septin was essential for normal branching and spine formation. An abundance of septin made dendrites grow and proliferate while a dearth of septin made them small and malformed.

"Boosting septin expression and function would enhance the stability of spines and synapses, and therefore be good for cognitive functions such as learning and memory," Sheng said. His laboratory is now exploring ways to prevent septin degradation and loss.

In addition to Sheng and Tada, authors are MIT affiliates Alyson Simonetta and Matthew Batterton; Makoto Kinoshita of Kyoto University Graduate School of Medicine; and Picower postdoctoral associate Dieter Edbauer.

This work is supported by the National Institutes of Health and the RIKEN-MIT Neuroscience Research Center

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Toxic Releases Down From North American Industry Leaders

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Pollution , and purification is always a burning question , awaring the CEC's goal ,The latest Taking Stock report from the Commission for Environmental Cooperation (CEC) reveals that a continued decline in releases of toxic chemicals to the environment--15 percent for the United States and Canada from 1998 to 2004--is being driven by a group of industrial facilities that are the largest generators of emissions
The CEC report, however, also reveals that the leading role of the largest waste-producing facilities stands in stark contrast to a substantial increase in chemical releases and transfers by a much larger group of industrial facilities that report lower volumes of emissions.

Released October 18, the annual report compares industrial pollution from a matched set of facilities in Canada and the United States--three million tonnes of chemicals released or transferred in the two countries in 2004. Over one-third of that amount was released at the location of reporting facilities, including over 700,000 tonnes released to the air, with another third transferred to recycling. For the first time, the CEC report also provides data from Mexico. Across the three countries, metals and their compounds--lead, chromium, nickel and mercury--were reported by the highest proportion of facilities.

"The evidence is clear that industry and government action to limit chemical releases is showing steady progress," said Adrián Vázquez-Gálvez, CEC's executive director. "It is equally clear that a large number of small and medium-size industrial facilities need to do a better job in reducing their waste and emissions if we are going to see even greater progress in North America. We trust the progress shown by industry leaders and the fact that pollution prevention is a proven strategy will encourage everyone to tackle pollution issues at the source."

The CEC's analysis demonstrates that facilities from Canada and the United States that reported pollution prevention activities--product and process redesign, spill and leak detection, and substituting raw materials--showed reductions from 2002--2004. Facilities not engaged in these activities did not show similar progress.

A new chapter provides a detailed look at industrial recycling, finding that over one-third of US and Canadian releases and transfers reported in 2004--more than 1 million tonnes--were recycled. Recycling has increased in recent years due to increases in production and in scrap metal prices. Most of the materials were metals, including copper, zinc, lead and their compounds.

The trilateral analysis is based on matched data from some 9 industrial sectors, 56 chemicals, and 10,000 facilities, comparing releases and transfers for similar facilities in Canada, Mexico and the United States. The report identifies a different pattern of releases and transfers in each of the three countries.

Comparisons of the three countries' industrial emissions will continue to improve as the CEC works with governments, industry and NGOs to expand the number of chemicals and facilities that are comparable.

Taking Stock compiles data from Canada's National Pollutant Release Inventory, the United States' Toxics Release Inventory, and, starting with its first year of mandatory reporting in 2004, Mexico's pollutant release and transfer register, the Registro de Emisiones y Transferencia de Contaminantes

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Nobel Awarded in economics for "mechanism design theory,"

"WHAT on earth is mechanism design?" was the typical reaction to this year's Nobel prize in economics, announced on October 15th. In this era of "Freakonomics", in which everyone is discovering their inner economist, economics has become unexpectedly sexy. So what possessed the Nobel committee to honour a subject that sounds so thoroughly dismal? Why didn't they follow the lead of the peace-prize judges, who know not to let technicalities about being true to the meaning of the award get in the way of good headlines?

In fact, despite its dreary name, mechanism design is a hugely important area of economics, and underpins much of what dismal scientists do today. It goes to the heart of one of the biggest challenges in economics: how to arrange our economic interactions so that, when everyone behaves in a self-interested manner, the result is something we all like. The word "mechanism" refers to the institutions and the rules of the game that govern our economic activities, which can range from a Ministry of Planning in a command economy to the internal organisation of a company to trading in a market.

The real world rarely behaves like economics models do, so mechanism design is used to design markets and auctions that will better reflect the actions of the participants. Mechanism design is also used to look at how companies behave and to consider how governments can best provision public goods like defense or infrastructure. In general, mechanism design is applied to interactions where people or companies participating in the mechanism may have reasons to behave in a non-truthful or less than optimal way, and attempts to create rules and incentives to discourage this unwanted behavior.

The winners of the 2007 Nobel Memorial Prize in Economics, announced yesterday, are Leonid Hurwicz, Eric Maskin, and Roger Myerson. The three men received the prize for their work on "mechanism design theory," a field of economics that focuses on creating incentives and rules for an economics interaction such that the desired outcome or some desirable properties are achieved.

Hurwicz began working on mechanism design over 50 years ago by applying mathematical analysis to companies and economics systems like capitalism and socialism. His major theoretical contribution is "incentive compatibility," where participants in a mechanism will want to vote or play honestly. It's an important result, since we tend to want mechanisms like voting systems to encourage truthful voting, rather than encouraging people to disguise their true opinions.

Although "mechanism design theory" may not sound like something you or I would need to interact with very much, it pops up in quite a few places. Take the upcoming 700MHz spectrum auctions, for example. For this auction, the government has some set of goals, including perhaps getting some payment and fairly allocating the spectrum. The companies also have goals, which may be to gobble up as much of the spectrum as possible. By applying some mechanism design theory to the situation, economists can then design an auction mechanism that best meets the goals of all the parties. This type of game theoretical analysis of auctions has been done by Roger Myerson, whose work has influenced these types of spectrum auctions.

Software patents are another area where mechanism design comes into play. One of the Nobel laureates, Eric Maskin, has done some work on patent valuation. In particular, Maskin is critical of the software patent system, which he believes is harmful to innovation when new inventions are closely related to old ones. His (very) basic argument is that in many technology fields, competition is actually better for firms in the long run. Patents generally lead to less innovation in a particular field, and also lead to less competition since companies can't work on the same types of products. Thus, in the end, patents are bad for software and technology companies, because of how they limit competition.

If you're at all interested in mechanism design theory, I would highly recommend checking out the scientific background for the prize, since it provides a nice overview of the key results from the work of Hurwicz, Maskin, and Myerson. It can be a bit daunting to delve into, particularly since it's not a field of economics that gets talked about at your average cocktail party, but it's worth a look due to the sheer number of social and governmental situations that rely on mechanism design to operate more efficiently

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