SciCafe: Expeditionary Gastronomy with Mark Siddall

Thursday, December 16 10:58 am

The hunt for parasites and blood-sucking leeches takes Museum Curator Mark Siddall, Division of Invertebrate Zoology, to many far-off destinations where life in the field presents its own culinary challenges. Whether gobbling guinea pigs or grubs, Dr. Siddall never loses his appetite for adventure.

Recorded at the Museum on November 3, 2010.

The next SciCafe takes place on January 5, 2011. Learn more about this popular, after-hours series of cocktails and discussion.

Podcast: Download | RSS | iTunes (1 hour, 5 mins, 78 MB)

Museum Links Evolutionary Biology and Human Health

Wednesday, June 09 6:22 pm

What does Darwin have to do with human disease? Quite a lot, it turns out, as the lessons of evolution, enhanced by sophisticated technologies such as gene sequencing, are being used to tease out the secrets of organisms that spread death and disability around the globe.

The American Museum of Natural History has taken a leading role in these efforts through ongoing collaborations between its evolutionary biologists and medical researchers to understand various threats to human health, from flu pandemics to malaria to the ravages of antibiotic-resistant bacteria.

This work was highlighted at a Science Breakfast panel discussion held last week at the Museum before an audience of medical and science writers.

Listen to the Podcast: Download | RSS | iTunes (1 hr 09 mins, 64 MB)

The panel included three curators from the Museum’s Division of Invertebrate Zoology who work under the auspices of the Sackler Institute for Comparative Genomics. Rob DeSalle, who moderated, Mark Siddall, and Ward Wheeler were joined by three medical scientists: New York University School of Medicine’s Jane Carlton, Albert Einstein College of Medicine’s Robert Burk, and Columbia University’s Paul Planet.

Museum scientists help medical researchers pin down the origin, evolution, and diversity of pathogens, and, perhaps most important, how they have adapted to us and we to them.

“Every doctor, whether they know it or not, is a natural historian,” said Planet, who studies infectious diseases in children and is also a research associate at the Museum.

Another key component of collaboration is the development of new tools to make sense of masses of raw data. Case in point: the Supramap, displayed by Wheeler, a powerful new computer application which allows researchers and public health officials to track the spread and mutation of a disease over time and place.

Of course, the ultimate goal of such supercomputing, genome-sequencing, and the building of evolutionary trees is to better predict pandemic outbreaks and to find better treatments, even cures.

Said Burk, who has worked with DeSalle on the molecular phylogeny of the human papillomavirus, which is linked to cervical cancer, for a decade:  ”From the medical perspective, I think it’s very clear that the better we understand the pathogenesis of any disease, the better we are able to intervene.”

The New T. rex: A Leech with an Affinity for Noses

Thursday, April 15 10:24 am

Stereomicrograph of Tyrannobdella rex jaw showing large teeth on a single jaw. by Phillips, et al. 2010

The new T. rex has ferociously large teeth lining a single jaw — but its length is less than two inches long. Tyrannobdella rex, a new species and genus of leech, was discovered when doctors plucked it from the nose of a girl who’d recently been bathing in an Amazonian river. Described in PLoS ONE, the blood sucker had led to the revision of a group of leeches that has a habit of feeding from body orifices of mammals.

“Because of our analysis of morphology and DNA, we think that Tyrannobdella rex is most closely related to another leech that gets into the mouths of livestock in Mexico,” says Anna Phillips, a graduate student affiliated with the American Museum of Natural History and the first author of the paper. The related species Pintobdella chiapasensis hails from Chiapas and is typically hosted by tapir and cows. Analysis of genetic sequences places these species with others found in the world’s tropics, suggesting that their common ancestor must have lived when the continents were pressed together into a single land mass, or before Pangaea broke up.

“We named it Tyrannobdella rex because of its enormous teeth,” says Mark Siddall, curator in the Division of Invertebrate Zoology. “Besides, the earliest species in this family of these leeches no-doubt shared an environment with dinosaurs about 200 million years ago, when some ancestor of our T. rex may have been up that other T. rex’s nose.”

For more on Mark Siddall, watch a recent field video of the curator searching for leeches in Rwanda.

Twenty Years of Summer Science at AMNH

Thursday, December 03 1:33 pm

Allyse Hellmich walked swiftly through the dark room to the podium, eyes widening at the laser pointer. “Oooh,” said the Grinnell College student, snatching it to point the red beam at her first slide. Her research on the genetic relationships of scarlet macaws in a Guatemalan zoo, which will help launch a breeding program to replenish the endangered wild population, was about to be presented to a group of American Museum of Natural History scientists who had trained her over the summer.

Allyse was just one of three dozen undergraduates who counted galaxies, measured bones, analyzed volcanic rock, or photographed microscopic fontanelle last summer as part of the Museum’s 2009 Research Experiences for Undergraduates, paid summer internships that offer college students the chance to conduct research at the Museum.

“One of my students will be presenting a poster at the next national geology meeting,” says Jim Webster, Curator of Physical Sciences. “It’s a fantastic program. You get wonderful students with lots of questions that breathe a bit of new life into the Museum.”

Last summer marked the 20th year of the Museum’s biology REU program, currently shepherded by Curator Mark Siddall. “This program has mentored nearly 200 students over the years,” he says. “These students go on to graduate school, work in scientific laboratories, and have even penned 20 peer-reviewed publications in the last five years.”

Applications for summer 2010 are due February 1. For more information about this National Science Foundation-funded program, please visit the Richard Gilder Graduate School at AMNH online at rggs.amnh.org.

Research carried out by the Museum’s REU students will help launch a breeding program for the scarlet macaw - Kari Schmidt

After Darwin at AMNH: Mark Siddall

Wednesday, November 04 4:43 pm

De-Leeching Ankles on a Desolate Coast with Mark Siddall, Curator of Invertebrate Zoology

This year, scientists at the American Museum of Natural History are celebrating the 200th anniversary of Charles Darwin’s birth and the 1859 publication of On the Origin of Species with a collection of vignettes describing expeditions and ideas with links to Darwin’s seminal work.

The Island of Chiloé may protect part of the Chilean coast from the winds of the Pacific Ocean, but it offers little refuge for the travelling naturalist.

Americobdella valdiviana exposed by turning over a rock - © M. Siddall

When Charles Darwin rode with his team across the island on January 22, 1835 he recalled a beautiful day and “trees…in full flower [that] perfumed the air.” Yet even this lovely vista “could hardly dissipate the effects of the gloomy dampness of the forest. Moreover, the many dead trunks that stand like skeletons never fail to give to these primeval woods a character of solemnity.”

More than 160 years later, Mark Siddall and his graduate student Liz Borda made a similar excursion to what is now the Parque Nacional de Chiloé. As they tramped through dense stands of old-growth Nothofagus and Fitzroya trees in intense wind and

driving rain, they found they shared Darwin’s observation that if they “could forget the gloom and ceaseless rain of winter, Chiloé might pass for a charming island.”

The project that brought Siddall and Borda to Chile shared something else with Darwin, too. “Our purpose in Southern Chile was to rediscover two species of leeches, Americobdella valdiviana and Mesobdella gemmata, that I thought were critical to understanding the evolution of this group,” says Siddall. “Transitional forms—species that have characteristics of two distinct but evolutionarily related groups—are central to Darwin’s theories.”

Read more »