MBL


For a young scientist, Hari Shroff, co-director of the Optical Microscopy and Imaging course at MBL, has seen his share of career peaks. Shroff entered the University of Washington at age 14 and graduated when many people are just starting college. After completing his doctorate in biophysics in 2006 at the University of California, Berkeley, Shroff took the MBL Physiology course. It had “a huge influence on me,” Shroff says in this interview with Prashant Prabhat of Semrock. “I was working hand-in-hand with a lot of the experts in cell biology,” Shroff recalls, and they drove home how fundamental microscopy is to their field.

That same year, Shroff heard microscope developer Eric Betzig give a talk at Berkeley. “I have always been very fascinated by the fundamental mismatch in size between what a biologist wants to see and what they actually can see,” Shroff tells Prabhat. “[Betzig] was talking a little bit about super-resolution, and I wanted to drop what I was doing and immediately work for him.” Shroff felt lucky to become one of Betzig’s first hires at his lab at Howard Hughes Medical Institute’s newly opened Janelia Research Campus.

Shroff came back to the MBL Physiology course in 2007 as a teaching assistant, along with Betzig as visiting faculty. And there was important cargo in their van when they drove to Woods Hole: the super-resolution microscope Betzig and colleagues had invented, called PALM (photoactivated localization microscopy), which Shroff had a hand in developing. The scope’s power to visualize individual molecules at nanometer resolution bowled over the Physiology course participants and soon became the talk of the MBL campus.

“Those were very heady, exciting times, but also sleepless times,” Shroff tells Prabhat. “Something very special happens [at the MBL] during the summer when you have these world-class scientists congregating for a couple of months. You end up with these collisions which are just difficult to have otherwise. People have this kind of ‘can do’ attitude about science, and it’s also a great place for microscopy because some of the world’s best microscopists usually hang out there during the summers.”

Hari Shroff of the NIH shows MBL Neurobiology course students the light-sheet microscope he built (diSPIM). Credit: Tom Kleindinst

Hari Shroff of the NIH shows MBL students the light-sheet microscope he built (diSPIM). Credit: Tom Kleindinst

Important applications of Betzig’s microscope came out of that Physiology course session, which was led by course co-director Jennifer Lippincott-Schwartz of the NIH, an early collaborator with Betzig on PALM. These included live-cell, single particle tracking (sptPALM), which Betzig says “has become one of the most useful and biologically informative applications of the technology. That idea was born while we were waiting for a ferry ride in Woods Hole.” They also figured out how to label two colors of photo-activatable probes (double-color PALM) during the course, which Shroff et al published later that year.

In 2014, Betzig won a Nobel Prize in Chemistry for his contributions to super-resolution fluorescence microscopy. Shroff, meanwhile, had become a section chief at the NIH’s National Institute of Biomedical Imaging and Engineering. He was also invited to co-direct the Optical Microscopy and Imaging course, where he shows students how to build a microscope from scratch, among other challenges. The course is a lot of work, Shroff says, but “definitely fun. I actually get some of my best ideas just from daydreaming and talking to students.”

 

Today is the last day to apply for a travel award to get to this neuroscience celebration! Details here.

It’s reunion time for the MBL SPINES course, with a day-long symposium planned for this fall in Chicago. Held a day before the annual Society for Neuroscience meeting, the symposium will be a chance to catch up with friends, network, attend presentations, and celebrate the community the SPINES course has created.

The Summer Program in Neuroscience, Ethics, & Survival (SPINES) is an intense, month-long program held each summer at the MBL since 1995. It integrates training in lab techniques, grant writing, ethics, and public speaking, among other skills essential for early-career scientists. The course is also a networking opportunity and a way to build community for underrepresented groups in science, the target audience for the course. This symposium will celebrate the achievements of alumni students and faculty and expand the SPINES network across years and career stages to promote networking and collaboration.

The symposium will be held on October 16th, 2015 at the University of Chicago, and there is still time to apply for a travel award to help get there. More information can be found here, and details on the travel grant can be found here. Please contact Chinonye Nnakwe, Ph.D., at spinessymposium(@)gmail.com with questions.

SPINES students hard at work in the lab. Photo credit: Tim Kleindinst

SPINES students hard at work in the lab. Photo credit: Tim Kleindinst

Call this the Age of the Microbiome. Just a few short years ago, in 2012, the first “map” of the microbial species that live on and in the human body was published. Today, the data just keep coming that reveal the myriad connections between a person’s health—or an organism’s behavior—and the status of his, her or its microbiome, with correlations found in traits ranging from obesity to autism to ulcerative colitis.

One of the researchers at the forefront of microbiome research is Jack Gilbert, group leader for Microbial Ecology at Argonne National Laboratory and Associate Professor at the University of Chicago, as well as a faculty member at MBL. Catch up with Gilbert and the latest frontiers in microbiome research here, in a detailed profile in this month’s issue of The University of Chicago Magazine.

Bacteria-forming-a-mixed-biofilm-on-colon-cancer-tissue.-Credit-Jessica-Mark-Welch,-Blair-Rossetti,-and-Christine-Dejea, MBL

Bacteria forming a mixed biofilm on colon cancer tissue. Credit Jessica Mark Welch, Blair Rossetti, and Christine-Dejea, MBL

By Kelsey Calhoun

Vision has been studied inside and out for more than a century, resulting in some textbooks presenting the visual system as essentially understood. But María Gomez and Enrico Nasi, adjunct scientists at the Marine Biological Laboratory (MBL), don’t agree. They have spent the last several years investigating non-visual photoreceptors, cells whose function remains elusive in eyes filled with rods and cones. They reveal an important clue to how these cells work—how calcium triggers the electrical light response— in a recent paper published in Proceedings of the National Academy of Sciences.

Enrico Nasi and Maria del Pilar Gomez

Enrico Nasi and Maria del Pilar Gomez

Studies of vision traditionally divided light-sensitive cells into two distinct classes: those of vertebrates and those of invertebrates. The two classes were so different from each other that they were thought to represent two separate lines of evolution. But a few phenomena presented problems with this view. The most dramatic is the fact that blind people, who lack functioning rods and cones—the only photoreceptive cells previously thought to exist in vertebrates—can recover from jet lag, somehow sensing the light that resets their circadian rhythms. “A new type of photosensitive cell was later discovered in the mammalian eye that is responsible for these functions,” says Nasi. “Another dogma bites the dust.”

It is these non-visual photoreceptors, sometimes called circadian photoreceptors, that Nasi and Gomez, both professors at the Universidad Nacional de Colombia, were interested in studying. “What are these sensors? The idea that they might be just like photoreceptors of invertebrates—this is beyond blasphemy,” says Nasi. If true, “this leads to rewriting the evolutionary history of vision.” But studying these cells presented a few practical challenges. In vertebrates, the cells are few and far between, and have no unique shapes or markers to make them easy to find.

Amphioxus can grow as long as 2.5 inches, and it is very difficult to tell their head from their tail. Other than that, they are a very useful animal model. Photo by Hans Hillewaert.

Amphioxus can grow as long as 2.5 inches, and it can be difficult to tell the head from the tail. Photo by Hans Hillewaert

So Gomez and Nasi turned to an unassuming, fish-like invertebrate called a lancelet or amphioxus. This creature holds a unique place on the evolutionary tree of life, at the branching point between vertebrates and invertebrates. It has other advantages: the photoreceptors that interest Gomez and Nasi are easy to find in the organism, and manipulate. The evidence they found in the simple amphioxus suggests that vertebrates’ non-visual photoreceptors may mimic those found in amphioxus—that the visual systems of vertebrates and invertebrates are not as different as previously thought.

Their paper tackles the final step of the pathway that lets these photoreceptors translate incoming light into signals to the organism. Most of the pathway was already known, but solid evidence for the last step was elusive: How was light converted to an electrical cell signal that could be communicated to other cells?

Gomez and Nasi investigated the flood of calcium that is released when the circadian photoreceptors were exposed to light. They showed that calcium provoked the electrical cell signal, very similar to what happens with normal light stimulation. “It reproduces the native response,” says Gomez. This flood of calcium is the link that lets these photoreceptors communicate with the rest of the organism.

“We’re rather happy to see something that fully reproduces the light response for the first time,” Nasi says. But, he adds, “We don’t want to make claims that this is going to be general to all species.” Whether this discovery proves to be common in other species or not, it’s clear the field of vision and light-sensing cells still has much to reveal.

Citation:
Peinado G, Orsano T, Gomez M, and Nasi E (2015). Calcium activates the light-dependent conductance in melanopsin-expressing photoreceptors in amphioxus. PNAS, DOI: 10.1073/pnas.1420265112

By Rachel Buhler

Two journalists who received fellowships from the MBL Logan Science Journalism Program are spending the next week with scientists pursuing environmental field research at Toolik Field Station in Arctic Alaska, including studies of global climate change.

SJPtoolik2015resized

Michael Werner and Meera Subramanian at the Arctic Circle, 150 miles north of Fairbanks.

The two fellows, freelance journalist Meera Subramanian and freelance journalist/ filmmaker Michael Werner, both attended the program’s hands-on course at the MBL in June, undertaking field and laboratory research to “step into the shows of the scientists they cover.”  Last Tuesday, they flew into Fairbanks, Alaska, as the starting point for their journey to Toolik, which entails a minimum eight-hour drive and a passage across the Arctic Circle.

Subramanian has been blogging  — with striking photos and videos of the Arctic tundra and its scientist inhabitants — on the program’s blog, “A Toolik Field Journal.”

Over the years, the Logan Science Journalism Program has granted fellowships to hundreds of journalists from prominent news organizations, including The New York Times, The Wall Street Journal, Science, National Public Radio, The Washington Post, USA Today, CNN, and Scientific American. Journalists from Africa, Brazil, Sweden, India, Japan, the United Kingdom and other countries have also received fellowships.

Next Page »