Five from Caltech Elected to American Academy of Arts and Sciences

The American Academy of Arts and Sciences has elected five Caltech community members as academy fellows. They are faculty members Michael B. Elowitz, professor of biology and bioengineering and an investigator with the Howard Hughes Medical Institute; Mory Gharib (PhD '83), Hans W. Liepmann Professor of Aeronautics and Bioinspired Engineering, director of the Ronald and Maxine Linde Institute of Economic and Management Sciences, and vice provost; and Linda C. Hsieh-Wilson, professor of chemistry; and Caltech trustees James Rothenberg and Maria Hummer-Tuttle. The American Academy is one of the nation's oldest honorary societies. Members are accomplished scholars and leaders representing diverse fields including academia, business, public affairs, the humanities, and the arts.

 

Michael B. Elowitz was noted for his work that "helped to initiate synthetic biology." Elowitz studies genetic circuits—interacting genes and proteins that enable cells to sense environmental conditions and to communicate. He and his group build simplified synthetic genetic circuits and study their effects in bacteria, yeast, and mammalian cells. He has received numerous honors in recognition of his work, including a MacArthur Fellowship in 2007.
 

Mory Gharib and his group use nature's own design principles—apparent in fins, wings, blood vessels, and more—as inspiration for a myriad of inventions. They have studied fluid flows inside the zebrafish heart to develop efficient micropumps and more efficient artificial heart valves, and cactus spine to develop arrays of nanoneedles, based on carbon nanotubes, for painless drug delivery. Gharib holds nearly 100 patents, and was elected to the National Academy of Engineering in 2015.

Linda C. Hsieh-Wilson was noted for her pioneering work in the new fields of chemical glycobiology and chemical neurobiology. Her work combines organic chemistry and neurobiology in order to understand how carbohydrates contribute to fundamental brain processes such as cell growth and neuronal communication, neural development, and memory at the molecular level. She and her group discovered a means for suppressing tumor-cell growth by blocking the attachment of certain sugars to proteins, restricting delivery of certain carbohydrates to proteins within the tumor.

Maria Hummer-Tuttle, a lawyer, was a partner and chair of the management committee and co–managing partner of Manatt, Phelps and Phillips in Los Angeles. She currently serves on the boards of Caltech, the J. Paul Getty Trust, the W. M. Keck Foundation, the Suu Foundation, and the Foundation for Art and Preservation in Embassies. Hummer-Tuttle is president of the Hummer Tuttle Foundation, serves on the advisory board of the USC Center on Public Diplomacy at the Annenberg School as well as on the program advisory committee of the Annenberg Retreat at Sunnylands, and is a member of the Pacific Council on International Policy, the Council on Foreign Relations, and the Getty Conservation Institute Council.

Jim Rothenberg is chairman of the Capital Group Companies, Inc. In addition to his service on the Caltech board, he serves on the boards of Capital Research and Management Company, the Capital Group Companies, Inc., and American Funds Distributors, Inc. In addition, he is a portfolio counselor for the Growth Fund of America, as well as vice chairman of the Growth Fund of America and Fundamental Investors. A chartered financial analyst, he was named to the Harvard Corporation as the treasurer of Harvard University in 2004. He also serves as a director of Huntington Memorial Hospital in Pasadena.

Elowitz, Gharib, and Hsieh-Wilson join 83 current Caltech faculty as members of the American Academy. Also included in this year's list are five alumni: Robert Cohen (MS '70, PhD '72), St. Laurent Professor of Chemical Engineering at MIT and codirector of the DuPont-MIT Alliance; Alexei Filippenko (PhD '84), professor of astronomy at UC Berkeley; Katherine Hayles (MS '69), professor of literature at Duke University; Michael Snyder (PhD'83), professor and chair of genetics at Stanford University; and Donald Truhlar (PhD '70), professor of chemistry at the University of Minnesota.

Founded in 1780 by John Adams, James Bowdoin, John Hancock, and other scholar-patriots, the academy aims to serve the nation by cultivating "every art and science which may tend to advance the interest, honor, dignity, and happiness of a free, independent, and virtuous people." The academy has elected as fellows and foreign honorary members "leading thinkers and doers" from each generation, including George Washington and Ben Franklin in the 18th century, Daniel Webster and Ralph Waldo Emerson in the 19th, and Albert Einstein and Woodrow Wilson in the 20th.

A full list of new members is available on the academy website at https://www.amacad.org/content/members/members.aspx.

The new class will be inducted at a ceremony on October 10, 2015, in Cambridge, Massachusetts.

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Understanding the Earth at Caltech

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Credit: Courtesy J. Andrade/Caltech

The ground beneath our feet may seem unexceptional, but it has a profound impact on the mechanics of landslides, earthquakes, and even Mars rovers. That is why civil and mechanical engineer Jose Andrade studies soils as well as other granular materials. Andrade creates computational models that capture the behavior of these materials—simulating a landslide or the interaction of a rover wheel and Martian soil, for instance. Though modeling a few grains of sand may be simple, predicting their action as a bulk material is very complex. "This dichotomy…leads to some really cool work," says Andrade. "The challenge is to capture the essence of the physics without the complexity of applying it to each grain in order to devise models that work at the landslide level."

Credit: Kelly Lance ©2013 MBARI

Geobiologist Victoria Orphan looks deep into the ocean to learn how microbes influence carbon, nitrogen, and sulfur cycling. For more than 20 years, her lab has been studying methane-breathing marine microorganisms that inhabit rocky mounds on the ocean floor. "Methane is a much more powerful greenhouse gas than carbon dioxide, so tracing its flow through the environment is really a priority for climate models and for understanding the carbon cycle," says Orphan. Her team recently discovered a significantly wider habitat for these microbes than was previously known. The microbes, she thinks, could be preventing large volumes of the potent greenhouse gas from entering the oceans and reaching the atmosphere.

Credit: NASA/JPL-Caltech

Researchers know that aerosols—tiny particles in the atmosphere—scatter and absorb incoming sunlight, affecting the formation and properties of clouds. But it is not well understood how these effects might influence climate change. Enter chemical engineer John Seinfeld. His team conducted a global survey of the impact of changing aerosol levels on low-level marine clouds—clouds with the largest impact on the amount of incoming sunlight Earth reflects back into space—and found that varying aerosol levels altered both the quantity of atmospheric clouds and the clouds' internal properties. These results offer climatologists "unique guidance on how warm cloud processes should be incorporated in climate models with changing aerosol levels," Seinfeld says.

Credit: Yan Hu/Aroian Lab/UC San Diego

Tiny parasitic worms infect nearly half a billion people worldwide, causing gastrointestinal issues, cognitive impairment, and other health problems. Biologist Paul Sternberg is on the case. His lab recently analyzed the entire 313-million-nucleotide genome of the hookworm Ancylostoma ceylanicum to determine which genes turn on when the worm infects its host. A new family of proteins unique to parasitic worms and related to the early infection process was identified; the discovery could lead to new treatments targeting those genes. "A parasitic infection is a balance between the parasites trying to suppress the immune system and the host trying to attack the parasite," Sternberg observes, "and by analyzing the genome, we can uncover clues that might help us alter that balance in favor of the host."

Credit: K.Batygin/Caltech

Earth is special, not least because our solar system has a unique (as far as we know) orbital architecture: its rocky planets have relatively low masses compared to those around other sun-like stars. Planetary scientist Konstantin Batygin has an explanation. Using computer simulations to describe the solar system's early evolution, he and his colleagues showed that Jupiter's primordial wandering initiated a collisional cascade that ultimately destroyed the first generation population of more massive planets once residing in Earth's current orbital neighborhood. This process wiped the inner solar system's slate clean and set the stage for the formation of the planets that exist today. "Ultimately, what this means," says Batygin, "is that planets truly like Earth are intrinsically not very common."

Credit: Nicolás Wey-Gόmez/Caltech

Human understanding of the world has evolved over centuries, anchored to scientific and technological advancements and our ability to map uncharted territories. Historian Nicolás Wey-Gόmez traces this evolution and how the age of discovery helped shape culture and politics in the modern era. Using primary sources such as letters and diaries, he examines the assumptions behind Europe's encounter with the Americas, focusing on early portrayals of native peoples by Europeans. "The science and technology that early modern Europeans recovered from antiquity by way of the Arab world enabled them to imagine lands far beyond their own," says Wey-Gómez. "This knowledge provided them with an essential framework to begin to comprehend the peoples they encountered around the globe."

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At Caltech, researchers study the Earth from many angles—from investigating its origins and evolution to exploring its geology and inner workings to examining its biological systems. Taken together, their findings enable a more nuanced understanding of our planet in all its complexity, helping to ensure that it—and we—endure. This slideshow highlights just a few of the Earth-centered projects happening right now at Caltech.

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Abedi Receives Fellowship for New Americans

Mohamad Abedi, a PhD candidate in bioengineering, has received a Paul & Daisy Soros Fellowship for New Americans. Thirty fellows were selected from nearly 1,200 applicants "for their potential to make significant contributions to US society, culture, or their academic field," according to the fellowship program description. Each Soros Fellow will receive up to $90,000 to help cover two years of tuition, and other educational and living expenses, while studying any subject at any university in the United States. The fellowship was established to assist young new Americans—permanent residents, naturalized citizens, or children of naturalized citizen parents—at critical points in their educations.

"I'm honored and excited to receive this fellowship. Coming to the United States provided me with a plethora of opportunities and support that allowed me to pursue my dream and be here at Caltech today," Abedi says.

Abedi was born to Palestinian refugees in the United Arab Emirates. As a child he frequently visited family in the Beddawi refugee camp in Lebanon. The lack of adequate health care resources he saw there motivated him to pursue a degree in bioengineering.

"As a bioengineer, I hope to develop low-cost medical technologies that could provide people with health care regardless of their geographical location and financial capabilities," Abedi says.

After moving with his family to California during his final year of high school, Abedi began a degree in biomedical engineering at UC Irvine, where he worked on building affordable diagnostic devices that could run on air instead of electricity. At UC Irvine, he also ventured into synthetic biology to study bacterial genetic circuits—interacting genes and proteins that enable cells to sense and communicate with one another.

Now a first-year graduate student in the lab of Mikhail Shapiro, assistant professor of chemical engineering, Abedi aims to develop tools for the noninvasive modulation of brain circuitry. These would eventually allow scientists to understand and treat neurological and psychiatric diseases involving the dysfunction of local neural circuits, such as depression or obsessive-compulsive disorder.

"Understanding the human brain, where trillions of cells work in harmony to form a magnificent structure, is arguably the most ambitious target of scientific inquiry," Abedi says. "I am interested in utilizing tools from cellular and molecular engineering to study the brain, with the overarching goal of improving human health and welfare worldwide."

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Oka Awarded Grant for "Exceptional Young Scientists"

Yuki Oka, an assistant professor of biology, has been named a 2015 Searle Scholar. The Searle Scholars Program provides grants to young faculty to support research in the biomedical sciences and chemistry. Fifteen scholars are named annually, each receiving $100,000 per year for three years.

"I'm very excited and honored by this award," says Oka, who studies how the brain compiles both internal and external sensory information in order to maintain homeostasis, or internal stability of the body. In particular, Oka's group studies how the brain controls the feeling of thirst, and how that feeling drives us to drink water. There are multiple processes involved in regulating thirst in the brain.  

"Our research group aims to understand how these thirst signals are processed in the brain and how they ultimately drive specific behavioral outputs," Oka says. "We recently identified two distinct neural populations controlling drinking behavior in two opposite directions: driving and suppressing thirst." By manipulating these neural populations in animals, the group found that it could artificially create or suppress the desire to drink water.

Before joining the faculty at Caltech, Oka was a postdoctoral scholar at Columbia University. He received his PhD from the University of Tokyo. He is the 18th current Caltech faculty member to be named a Searle Scholar.

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Microbes Help Produce Serotonin in Gut

Although serotonin is well known as a brain neurotransmitter, it is estimated that 90 percent of the body's serotonin is made in the digestive tract. In fact, altered levels of this peripheral serotonin have been linked to diseases such as irritable bowel syndrome, cardiovascular disease, and osteoporosis. New research at Caltech, published in the April 9 issue of the journal Cell, shows that certain bacteria in the gut are important for the production of peripheral serotonin.

"More and more studies are showing that mice or other model organisms with changes in their gut microbes exhibit altered behaviors," explains Elaine Hsiao, research assistant professor of biology and biological engineering and senior author of the study. "We are interested in how microbes communicate with the nervous system. To start, we explored the idea that normal gut microbes could influence levels of neurotransmitters in their hosts."

Peripheral serotonin is produced in the digestive tract by enterochromaffin (EC) cells and also by particular types of immune cells and neurons. Hsiao and her colleagues first wanted to know if gut microbes have any effect on serotonin production in the gut and, if so, in which types of cells. They began by measuring peripheral serotonin levels in mice with normal populations of gut bacteria and also in germ-free mice that lack these resident microbes.

The researchers found that the EC cells from germ-free mice produced approximately 60 percent less serotonin than did their peers with conventional bacterial colonies. When these germ-free mice were recolonized with normal gut microbes, the serotonin levels went back up—showing that the deficit in serotonin can be reversed.

"EC cells are rich sources of serotonin in the gut. What we saw in this experiment is that they appear to depend on microbes to make serotonin—or at least a large portion of it," says Jessica Yano, first author on the paper and a research technician working with Hsiao.

The researchers next wanted to find out whether specific species of bacteria, out of the diverse pool of microbes that inhabit the gut, are interacting with EC cells to make serotonin.

After testing several different single species and groups of known gut microbes, Yano, Hsiao, and colleagues observed that one condition—the presence of a group of approximately 20 species of spore-forming bacteria—elevated serotonin levels in germ-free mice. The mice treated with this group also showed an increase in gastrointestinal motility compared to their germ-free counterparts, and changes in the activation of blood platelets, which are known to use serotonin to promote clotting.

Wanting to home in on mechanisms that could be involved in this interesting collaboration between microbe and host, the researchers began looking for molecules that might be key. They identified several particular metabolites—products of the microbes' metabolism—that were regulated by spore-forming bacteria and that elevated serotonin from EC cells in culture. Furthermore, increasing these metabolites in germ-free mice increased their serotonin levels.

Previous work in the field indicated that some bacteria can make serotonin all by themselves. However, this new study suggests that much of the body's serotonin relies on particular bacteria that interact with the host to produce serotonin, says Yano. "Our work demonstrates that microbes normally present in the gut stimulate host intestinal cells to produce serotonin," she explains.

"While the connections between the microbiome and the immune and metabolic systems are well appreciated, research into the role gut microbes play in shaping the nervous system is an exciting frontier in the biological sciences," says Sarkis K. Mazmanian, Luis B. and Nelly Soux Professor of Microbiology and a coauthor on the study. "This work elegantly extends previous seminal research from Caltech in this emerging field".

Additional coauthor Rustem Ismagilov, the Ethel Wilson Bowles and Robert Bowles Professor of Chemistry and Chemical Engineering, adds, "This work illustrates both the richness of chemical interactions between the hosts and their microbial communities, and Dr. Hsiao's scientific breadth and acumen in leading this work."

Serotonin is important for many aspects of human health, but Hsiao cautions that much more research is needed before any of these findings can be translated to the clinic.

"We identified a group of bacteria that, aside from increasing serotonin, likely has other effects yet to be explored," she says. "Also, there are conditions where an excess of peripheral serotonin appears to be detrimental."

Although this study was limited to serotonin in the gut, Hsiao and her team are now investigating how this mechanism might also be important for the developing brain. "Serotonin is an important neurotransmitter and hormone that is involved in a variety of biological processes. The finding that gut microbes modulate serotonin levels raises the interesting prospect of using them to drive changes in biology," says Hsiao.

The work was published in an article titled "Indigenous Bacteria from the Gut Microbiota Regulate Host Serotonin Biosynthesis." In addition to Hsiao, Yano, Mazmanian, and Ismagilov, other Caltech coauthors include undergraduates Kristie Yu, Gauri Shastri, and Phoebe Ann; graduate student Gregory Donaldson; postdoctoral scholar Liang Ma. Additional coauthor Cathryn Nagler is from the University of Chicago.

This work was funded by an NIH Director's Early Independence Award and a Caltech Center for Environmental Microbial Interactions Award, both to Hsiao. The study was also supported by NSF, NIDDK, and NIMH grants to Mazmanian, NSF EFRI and NHGRI grants to Ismagilov, and grants from the NIAID and Food Allergy Research and Education and University of Chicago Digestive Diseases Center Core to Nagler.

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Thursday, July 2, 2015
Athenaeum, Main Lounge

Ray D. Owen Memorial

A Molecular Arms Race: The Immune System Versus HIV

Watson Lecture Preview

It is now more than 30 years after the first AIDS epidemic, and an effective vaccine against HIV does not yet exist—partly because the virus quickly mutates to evade the vaccine's antibodies. On Wednesday, April 1, at 8 p.m. in Caltech's Beckman Auditorium, Pamela J. Bjorkman, Caltech's Max Delbrück Professor of Biology and an investigator with the Howard Hughes Medical Institute, will describe ways to neutralize that mutational advantage. Admission is free.

 

What do you do?

We are structural biologists who use various imaging techniques to look at biological macromolecules and assemblies, sometimes in purified forms and sometimes in tissues. For example, we study HIV proteins alone, on viruses, and on viruses in tissues during an infection. Utilizing high-resolution structures of individual proteins, we are trying to apply our knowledge of the chemistry of protein-protein interactions to understanding what makes some antibodies produced by HIV-infected people good at neutralizing viruses and other antibodies less effective. We then try to reengineer good antibodies to make them even better in hopes that they could be used therapeutically to prevent or treat HIV infection.

 

What's the neatest thing about what you do?

Using imaging techniques such as X-ray crystallography and electron microscopy, we can visualize structures in three dimensions, sometimes even localizing all of the atoms in a protein structure. This feels a bit like spying on nature—forcing her to reveal secrets that we can hopefully use to combat HIV/AIDS.

 

How did you get into this line of work?

I was hooked after taking chemistry in high school. I knew then that I wanted to use chemistry to understand biology. I became interested in HIV about 10 years ago when I started teaching the Caltech freshman biology class and used HIV as a model system to understand basic principles of biology, especially evolution. HIV is an amazing example of successful evolution against which the human immune system loses, but I hope that we can win the war against HIV through a fundamental understanding of how it works.

 

Named for the late Caltech professor Earnest C. Watson, who founded the series in 1922, the Watson Lectures present Caltech and JPL researchers describing their work to the public. Many past Watson Lectures are available online at Caltech's iTunes U site.

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Friday, April 10, 2015
Noyes 147 (J. Holmes Sturdivant Lecture Hall) – Arthur Amos Noyes Laboratory of Chemical Physics

Transforming Chemistry Education

Research Suggests Brain's Melatonin May Trigger Sleep

If you walk into your local drug store and ask for a supplement to help you sleep, you might be directed to a bottle labeled "melatonin." The hormone supplement's use as a sleep aid is supported by anecdotal evidence and even some reputable research studies. However, our bodies also make melatonin naturally, and until a recent Caltech study using zebrafish, no one knew how—or even if—this melatonin contributed to our natural sleep. The new work suggests that even in the absence of a supplement, naturally occurring melatonin may help us fall and stay asleep.

The study was published online in the March 5 issue of the journal Neuron.

"When we first tell people that we're testing whether melatonin is involved in sleep, the response is often, 'Don't we already know that?'" says Assistant Professor of Biology David Prober. "This is a reasonable response based on articles in newspapers and melatonin products available on the Internet. However, while some scientific studies show that supplemental melatonin can help to promote sleep, many studies failed to observe this, so the effectiveness of melatonin supplements is controversial. More importantly, these studies don't tell you anything about what naturally occurring melatonin normally does in the body."

There are several factors at play when you are starting to feel tired. Sleep is thought to be regulated by two mechanisms: a homeostatic mechanism, which responds to the body's internal cues for sleep, and a circadian mechanism that responds to external cues such as darkness and light, signaling appropriate times for sleep and wakefulness.

For years, researchers have known that melatonin production is regulated by the circadian clock, and that animals produce more of the hormone at night than they do during the day. However, this fact alone is not enough to prove that melatonin promotes sleep. For example, although nocturnal animals sleep during the day and are active at night, they also produce the most melatonin at night.

In the hopes of determining, once and for all, what role the hormone actually plays in sleep, Prober and his team at Caltech designed an experiment using the larvae of zebrafish, an organism commonly used in research studies because of its small size and well-characterized genome. Like humans, zebrafish are also diurnal—awake during the day and asleep at night—and produce melatonin at night.

But how exactly can you tell if a young zebrafish has fallen asleep? There are behavioral criteria—including how long a zebrafish takes to respond to a stimulus, like a knock on the tank, for example. "Based on these criteria, we found that if the zebrafish larvae don't move for one or more minutes, they are in a sleep-like state," Prober says.

To test the effect of naturally occurring melatonin on sleep, the researchers first compared the sleep patterns of normal, or "wild-type," zebrafish larvae to those of zebrafish larvae that are unable to produce the hormone because of a mutation in a gene called aanat2. They found that fish with the mutation slept only half as long as normal fish. And although a normal zebrafish begins to fall asleep about 10 minutes after "lights out"—about the same amount of time it takes a human to fall asleep—it took the aanat2 mutant fish about twice as long.

"This result was surprising because it suggests that almost half of the sleep that the larvae are getting at night is due to the effects of melatonin," Prober says. "That suggests that melatonin normally plays an important role in sleep and that you need this natural melatonin both to fall asleep and to stay asleep."

In both humans and zebrafish, melatonin is produced in a part of the brain called the pineal gland. To confirm that the mutation-induced reduction in sleep was actually due to a lack of melatonin, the researchers next used a drug to specifically kill the cells of the pineal gland, thus halting the hormone's production. The drug-treated fish showed the same reduction in sleep as fish with mutated aanat2. When the drug treatment stopped, allowing pineal gland cells to regenerate, the fish returned to a normal sleep pattern.

Sleep patterns, like many other biological and behavioral processes, are known to be regulated by the circadian clock. In an organism, the circadian clock aligns these processes with daily changes in the environment, such as daylight and darkness at night. However, while a great deal is known about how the circadian clock works, it was not known how the clock regulates sleep. Because the researchers had determined that melatonin is involved in promoting natural sleep, they next asked whether melatonin mediates the circadian regulation of sleep.

They first raised both wild-type and aanat2 mutant zebrafish larvae in a normal light/dark cycle—14 hours of light followed by 10 hours of darkness—to entrain their circadian clocks. Then, when the larvae were 5 days old, they switched both populations to an environment of constant darkness. In this "free running" condition, the circadian clock continues to function in the absence of daily light and dark signals from the environment. As expected, the wild-type fish maintained their regular circadian sleep cycle. The melatonin-lacking aanat2 mutants, however, showed no cyclical sleep patterns.  

"This was really surprising," says Prober. "For years, people have been looking in rodents for a factor that's required for the circadian regulation of sleep and have found a few other candidate molecules that, like melatonin, are regulated by the circadian clock and can induce sleep when given as supplements. However, mutants that lack these factors had normal circadian sleep cycles," says Prober. "One thought was that maybe all of these molecules work together and that you'd have to make mutations in multiple genes to see an effect. But we found that eliminating one molecule, melatonin, is the whole show. It's one of those rare and surprisingly clear results."

After finding that melatonin is necessary for the circadian regulation of sleep, Prober next wanted to ask how it does this. To find out, Prober and his colleagues looked to a neuromodulator called adenosine—part of the homeostatic mechanism that promotes sleep. As an animal expends energy throughout the day, adenosine accumulates in the brain causing the animal to feel more and more tired—a pressure that is relieved through sleep.

The researchers treated both wild-type and melatonin-deficient aanat2 mutant fish with drugs that activate adenosine signaling. They found that although the drugs had no effect on the wild-type fish, they restored normal sleep amounts in aanat2 mutants. This result suggests that melatonin may be promoting sleep, in part, by turning on adenosine—providing a long sought-after link between the homeostatic and circadian processes that regulate sleep.

Prober and his colleagues hypothesize that the circadian clock drives the production of melatonin, which then promotes sleep through yet-to-be-determined mechanisms while also stimulating adenosine production, thus promoting sleep through the homeostatic pathway. Although more experiments are needed to confirm this model, Prober says that the preliminary results may offer insights about human sleep as well.

"Zebrafish are vertebrates and their brain is structurally similar to ours. All of the markers that we and others have tested are expressed in the same regions of the zebrafish brain as in the mammalian brain," he says. "Zebrafish sleep and human sleep are likely different in some ways, but all of our drug and genetic data indicate that the same factors—working through the same mechanisms—have similar effects on sleep in zebrafish and mammals. "

Prober's work with the circadian regulation of sleep follows in the conceptual—and physical—footsteps of late Caltech geneticist Seymour Benzer, who founded genetic studies of the circadian clock. In experiments in fruit flies, Benzer and his graduate student, the late Ronald Konopka (PhD '72), discovered the first circadian-rhythm mutants. Benzer passed away in 2007, and when Prober came to Caltech in 2009, he was offered Benzer's former office and lab space. "Seymour Benzer's work in fruit flies launched the beginning of our understanding of the molecular circadian clock," Prober says, "so it's really special to be in this space, and it's gratifying that we're taking the next step based on his work."

The results of Prober's study are published in the journal Neuron in an article titled, "Melatonin is required for the circadian regulation of sleep." Other Caltech coauthors on the paper are graduate student Avni Gandhi and postdoctoral scholars Eric Mosser and Grigorios Oikonomou. This work was funded by grants from the National Institutes of Health, the Mallinckrodt Foundation, the Rita Allen Foundation, the Brain and Behavior Research Foundation as well as a Della Martin Postdoctoral Fellowship to Mosser.

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Tuesday, April 7, 2015
Dabney Hall, Lounge – Dabney Hall

Caltech Roundtable: Writing Popular Books about Science

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