If you check the MBL’s Twitter feed during the summer months, you’ll be treated to quick, highly enthusiastic, and often visually beautiful dispatches from the MBL’s Summer Courses. The students and faculty are pursuing up-to-the-minute questions in life sciences research using a wide array of high-end imaging equipment, and some of the images they produce are eye-popping. Here are just a few recent Twitter posts from MBL students and faculty:

Vincent Boudreau (@viboud), a graduate student in the Physiology Course from University of North Carolina, Chapel Hill, Tweeted out this video, which he and several students made during the course’s biochemistry bootcamp under the supervision of Sabine Petry of Princeton University and Robert Fischer of the National Institutes of Health. “This bootcamp experiment taught us students how to do the biochemical legwork involved to get these microtubules to give us such stunning images,” Boudreau says. Microtubules (red) can be seen branching off of one another, marked by the green EB1 protein at their outwardly growing extremity. Video made with a Nikon TIRF microscope.

The MBL Embryology Course, tweeting under the hashtag #embryo2015, has shared one striking image after another. This is a tardigrade (a bizarre-looking, microscopic, water-dwelling animal) imaged with light-sheet microscopy by two students in the course: Christina Zakas, a post-doc at New York University who tweets @CZakDerv, and Nick Shikuma, a post-doc at Caltech.


Tardigrade stained with DAPI to highlight nuclei and imaged on the Zeiss lighsheet Z1. Credit: C. Zakas and N. Shikuma, MBL Embryology course

Speaking of Embryology, several students in the course are blogging about their MBL experiences at the Node, an online community resource run by The Company of Biologists.  Check out their impressions of the course — its sheer intensity, its “exquisite coordination,” and the fun that balances all the hard work.

Embryology Course Co-director Alejandro Sánchez Alvarado, an expert Tweeter, once in a while reminds the students to step back from the bench, take a deep breath, and enjoy the beauty of Woods Hole. He called this scene “the rewards of Eel Pond after a rich day of learning and experimentation.”

Eel Pond, Woods Hole. Credit: Alejandro Sánchez Alvarado of the Stowers Institute/HHMI

Eel Pond, Woods Hole. Credit: Alejandro Sánchez Alvarado of the Stowers Institute/HHMI


The Oosight(R) product line of microscopes, developed at the MBL  and commercialized by Cambridge Research & Instrumentation, Inc. (CRi), has been acquired by Hamilton Thorne, Ltd., a provider of precision laser devices and image analysis systems for the fertility, stem cell, and developmental biology research markets.

Widely used in fertility clinics to assess the health of unfertilized eggs (oocytes), the Oosight system provides live, high-contrast images and captures quantitative data on important oocyte structures using a patented, non-invasive, polarized-light technique. The technology was developed at the MBL by Rudolf Oldenbourg, Michael Shribak and colleagues in the 1990s and 2000s and commercialized by CRi as LC-PolScope(TM) technology. The Oosight system’s visualization capabilities have enabled breakthroughs in assisted reproductive technology, stem cell generation, and developmental biology research.

Visualization of the meiotic spindle in a rhesus monkey oocyte (egg) using the OosightTM spindle imaging system during enucleation. The spindle is near the 12 o'clock position in the egg. Credit: From Byrne, et al. 2007. Nature 450: 497-502 (Supplementary Material).

Visualization of the meiotic spindle in a rhesus monkey egg using the Oosight spindle imaging system during enucleation. The spindle is near the 12 o’clock position in the egg. Credit: Byrne et al (2007) Producing primate embryonic stem cells by somatic cell nuclear transfer. Nature 450: 497-502.

“The Oosight system is a unique instrument that is complementary to our laser products in both fertility and developmental biology research labs,” remarked David Wolf, President and CEO of Hamilton Thorne. “As a long-term distributor of the Oosight system we have already completed the technical integration of the Oosight with our laser products. We believe that by leveraging our established, world-wide sales channels and investing in product marketing, we can generate incremental sales of the Oosight product.”

Additional information on the Oosight product and its multiple applications can be found at


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Contact: Diana Kenney, Marine Biological Laboratory

WOODS HOLE, Mass.—How a brilliant-green sea slug manages to live for months at a time “feeding” on sunlight, like a plant, is clarified in a recent study published in The Biological Bulletin.

The authors present the first direct evidence that the emerald green sea slug’s chromosomes have some genes that come from the algae it eats.

These genes help sustain photosynthetic processes inside the slug that provide it with all the food it needs.

Importantly, this is one of the only known examples of functional gene transfer from one multicellular species to another, which is the goal of gene therapy to correct genetically based diseases in humans.

“Is a sea slug a good [biological model] for a human therapy? Probably not. But figuring out the mechanism of this naturally occurring gene transfer could be extremely instructive for future medical applications,” says study co-author Sidney K. Pierce, an emeritus professor at University of South Florida and at University of Maryland, College Park.

The rich green color of the photosynthesizing sea slug, Elysia chlorotica, helps to camouflage it on the ocean floor. Credit: Patrick Krug

The rich green color of the photosynthesizing sea slug, Elysia chlorotica, helps to camouflage it on the ocean floor. Credit: Patrick Krug

The team used an advanced imaging technique to confirm that a gene from the alga V. litorea is present on the E. chlorotica slug’s chromosome. This gene makes an enzyme that is critical to the function of photosynthetic “machines” called chloroplasts, which are typically found in plants and algae.

It has been known since the 1970s that E. chloritica “steals” chloroplasts from V. litorea (called “kleptoplasty”) and embeds them into its own digestive cells. Once inside the slug cells, the chloroplasts continue to photosynthesize for up to nine months—much longer than they would perform in the alga. The photosynthesis process produces carbohydrates and lipids, which nourish the slug.

How the slug manages to maintain these photosynthesizing organelles for so long has been the topic of intensive study and a good deal of controversy. “This paper confirms that one of several algal genes needed to repair damage to chloroplasts, and keep them functioning, is present on the slug chromosome,” Pierce says. “The gene is incorporated into the slug chromosome and transmitted to the next generation of slugs.” While the next generation must take up chloroplasts anew from algae, the genes to maintain the chloroplasts are already present in the slug genome, Pierce says.

“There is no way on earth that genes from an alga should work inside an animal cell,” Pierce says. “And yet here, they do. They allow the animal to rely on sunshine for its nutrition. So if something happens to their food source, they have a way of not starving to death until they find more algae to eat.”

This biological adaptation is also a mechanism of rapid evolution, Pierce says. “When a successful transfer of genes between species occurs, evolution can basically happen from one generation to the next,” he notes, rather than over an evolutionary time scale of thousands of years.


Schwartz JA, Curtis NE, and Pierce SK (2014) FISH labeling reveals a horizontally transferred algal (Vaucheria litorea) nuclear gene on a sea slug (Elysia chlorotica) chromosome. Biol. Bull. 227: 300-312.


The Biological Bulletin is a peer-reviewed, trans-disciplinary international journal that publishes outstanding experimental research on a wide range of organisms and biological topics, with a focus on marine models. Published since 1897 by the Marine Biological Laboratory, it is one of America’s oldest and most respected journals.

The Marine Biological Laboratory (MBL) is dedicated to scientific discovery and improving the human condition through research and education in biology, biomedicine, and environmental science. Founded in Woods Hole, Massachusetts, in 1888, the MBL is a private, nonprofit institution and an affiliate of the University of Chicago.

MBL Adjunct Scientist Amy Gladfelter can now add “video producer” to her resume. Tapped to make her science “visible to the world” by Celldance Studios, a project of the American Society for Cell Biology (ASCB), Gladfelter came up with an aesthetically beautiful, simply told video about her discoveries of what goes wrong when cells form toxic aggregates, such as in Alzheimer’s disease. Her mini-movie, called “Companions in Discovery,” was filmed partly at MBL and partly at Dartmouth College, where she is an Associate Professor of Biological Sciences. It premiered for an appreciative audience in December at the ASCB annual meeting in Philadelphia.

“I like the end of the film, where members of [Gladfelter’s] lab talk briefly on camera. These young faces are the future of cell biology,” said Simon Atkinson, chairman of the ASCB’s Public Information Committee, which sponsors Celldance Studios.

Celldance Studios gave Gladfelter $1,000 to underwrite her costs, and provided video editing and post-production support. The original score is by Hollywood film composer Ted Masur, son of cell biologist Sandra Masur. More information is here.


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By Wallace Marshall
Co-director, MBL Physiology Course

Last month, I had a problem. I was teaching in the MBL Physiology course, using the giant, single-celled organism Stentor as a model system for students to learn quantitative approaches in cell biology. Stentor, which live in ponds, eat by creating a vortex of water that drags food into the cell’s mouth. The flow is created by thousands of cilia—tiny, hair-like cell parts that swing back and forth pushing fluid around. (Cilia are also critical for making the mucus in your airway flow away from your lungs, and patients with defects in these cilia can be really sick. So the question of how cilia make fluid flow is very important from a medical perspective. )

Stentor is a genus of large, trumpet-shaped ciliates, commonly found in freshwater ponds. Credit: EOL / micro*scope

Stentor is a genus of large, trumpet-shaped ciliates, commonly found in freshwater ponds. Credit: EOL / micro*scope

One of the students in our class, Shashank Shekhar from the CNRS Institute, France, had become interested in how the cell generates this pattern of fluid flow. Shashank started tracking the flow by putting small plastic beads into the water around the Stentor and then taking video images of the beads moving. This is a pretty standard approach in fluid dynamics called particle image velocimetry (PIV). But it’s not that commonly used in biology, and we didn’t entirely know what we were doing. The software we had been trying to use to track these particles didn’t give really nice flow lines. So this was the problem: How to use the flow of these tiny beads to figure out the pattern of flow around the cell as it feeds.

Frustrated by this problem, I decided to go get some coffee from Woods Hole Market. On the way back, I ran into my colleague Magdalena Bezanilla, an MBL Whitman Investigator from University of Massachusetts, Amherst, who works on cell biology. She thinks a lot about things moving inside cells so I figured I could get her input into our PIV challenge.

We ended up chatting about the problem in the MBL’s Waterfront Park, and while we were talking, a couple of guys emerged from the harbor in full scuba gear, carrying a huge metal bracket upon which was mounted a video camera and a laser. (This would be quite weird back home but it’s business as usual in Woods Hole.) I asked the guys what they were up to and they said they were using PIV to study the flow of fluid around ctenophores! Ctenophores or comb jellies are jellyfish-like animals that swim using cilia. So at the exact moment that we were pondering how to use PIV to track cilia-generated fluid flow in our single-celled organisms in the Physiology course, a guy walks out of the water and announces that he is doing the exact same thing, for comb jellies! (Those people who say that Woods Hole is a magical place are telling the truth.)

The guys with the scuba gear and lasers were Jack Costello of Providence College and Sean Colin of Roger Williams University, Whitman Investigators working for the summer at the MBL. Jack offered to give us advice about how to analyze our data, so I sent Shashank over to Jack’s lab in the Rowe building. With Jack’s help and expertise, Shashank was able to get beautiful flow lines from his data (see photo), which clearly reveal the pattern of cilia-generated flow around the Stentor cell while it feeds. Our big problem was solved in a single day due to a fortuitous combination of people, courses, coffee breaks, cells, beaches, marine organisms, and advanced technology. And that’s what summer at the MBL is all about.

Fluid flow around Stentor visualized through particle image velocimetry. Courtesy of Wallace Marshall.

Fluid flow around Stentor as it feeds, visualized by particle image velocimetry. Courtesy of Wallace Marshall.

Thank you to Wallace Marshall of the University of California, San Francisco, for contributing this post. All MBL scientists, students, community members, and visitors are invited to submit items for the MBL’s blog. Please contact Diana Kenney:

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