Past Issues About Edge

While other archaeologists are digging up bones, Gary Crawford is looking for seeds. Plant debris that has been buried for thousands of years reveals that cities in China had specialized agriculture as early as 2000 to 2500 BC, says Crawford, chair of Anthropology at the University of Toronto at Mississauga.

An expert in palaeoethnobotany, Crawford studies the relationships between people and plants through time. At archaeological sites, he takes the soil from fireplaces, floors and anywhere dinner scraps have been tossed. He submerges the soil in water and skims off material that floats to the surface for analysis.

Using this simple flotation method, Crawford learned that the ancestors of the Ainu in northern Japan had begun farming by 700 AD. When he examined plant remains taken from pre-Iroquoian settlements in southern Ontario, the parallels were remarkable: both the ancestral Ainu and the pre-Iroquoians, continents apart yet at the same northern latitude and at similar times, were taking up farming and ate domestic and wild plants, wild animals and fish.

The people of the Yellow River Valley of north-central China, in contrast, had begun to focus on grains thousands of years earlier. By 2000 BC, they lived in cities and ate millet, rice and even wheat, which is not native to China. It was provided by surrounding farms, says Crawford.

"There were specialists - there was probably a peasant class that produced the crops and elite people who were concerned with governance and religion." Plant debris shows that the combination of wheat and rice, which is seen as the basis for the modern Chinese agricultural economy, goes back much farther than previously thought. The lack of wood charcoal in the debris shows wood had already become too precious to burn for fuel - an indication that urban life had significantly reduced forest cover in parts of northern China by 2000 BC.

When the Chinese government opened its doors to foreign archaeologists in the 1990s, Crawford had been preparing for two decades to work there.

Recently, a colleague in China has been looking at a site in Inner Mongolia dating from about 6000 to 7000 BC, one of the oldest towns in China. "It is loaded with the remains of agriculture," says Crawford. "If we can study the earlier 7000 to 9000 BC period, when these small towns were forming, we may finally understand if there are any universal reasons why people move from hunting and gathering to agriculture." On a recent trip to China, Crawford learned that a site from this early period has just been found. He plans to develop a collaborative investigation of the site.

- Janice Walls

Can theatre education help motivate urban high school students who are at risk of failure? Kathleen Gallagher believes it can.

From 1989 to 1999, Gallagher - now an associate professor of Curriculum, Teaching and Learning at the Ontario Institute for Studies in Education at the University of Toronto (OISE-UT) - was a drama teacher at a Toronto high school that had a diverse student population, including many refugees and first-generation immigrants.

"This is when I began to realize that theatre could educate in important ways that are different from other subject areas and from the traditional notion of high school theatre class. The drama classroom became a world in which they could critically examine their challenges, explore their dreams and play out their real-life dramas."

Gallagher, who joined OISE-UT in 1999, earned her doctorate in education from U of T while teaching high school. She is pursuing her research as the recently-appointed Canada Research Chair in Urban School Research in Pedagogy and Policy.

"Theatre class in school can, of course, introduce students to the stage and can even prepare some for a career in the theatre. But it goes beyond that. It can have particular relevance for urban students who often face greater systemic barriers than other more privileged students."

Gallagher will test her theories in a variety of school settings in Canada, the United States, Great Britain, Australia, Belgium and Singapore, areas where she has already conducted research with grants from the Social Sciences and Humanities Research Council of Canada.

Gallagher is also the academic director of the new Centre for Urban Schooling. In one of the Centre's first projects - a collaboration between OISE-UT and the Toronto District School Board (TDSB) - U of T faculty and TDSB educational experts will work together to improve education and address systemic barriers for under-served youth in Toronto's schools.

For Gallagher, the power of theatre education has roots in her own history. "When I was four-years old, my older sister had just started high school and was taking a fantastic theatre arts program. I would sit mesmerized as she rehearsed her monologues. It had an enormous impact on me. Since then, I've never thought of theatre education as a frill. It engaged my imagination in profound ways."

- Paul Fraumeni

Biofilms are everywhere. They form around bacteria, making them highly resistant to disinfectants, antibiotics and the human immune system. Biofilms can be as benign as the slimy substance on river rocks or as dangerous as the contaminating deposits on catheters and pacemakers.

Few biofilms, however, are as infamous as dental plaque which can lead to cavities, periodontal diseases and endocarditis, a potentially fatal infection of the heart's inner lining.

U of T boasts a biofilm expert in Dennis Cvitkovitch, an associate professor in the Faculty of Dentistry and the Institute of Biomaterials and Biomedical Engineering and Canada Research Chair in Biofilm Genetics and Physiology. Cvitkovitch not only discovered that a signalling pathway activated by a Competence Stimulating Peptide (CSP) is associated with the formation of dental plaque, but he has also developed a technology that inhibits CSP from performing its essential role in plaque formation.

In 2000, Cvitkovitch and members of his lab, Yung-Hua Li and Peter C.Y. Lau, identified the DNA coding for the Streptococcus mutans (S. mutans) CSP.

S. mutans lives on the surface of teeth and is the main contributor to dental decay. "We found that this molecule was able to turn on a number of genetic circuits including those involved in picking up foreign DNA and incorporating it," says Cvitkovitch. "At the same time, we deduced that the signal molecules functioned when the cells lived on the surface."

The evidence also pointed to CSP as being a key regulator of biofilm growth and a good target to manipulate bacteria's ability to survive in the plaque environment.

Three years later, Cvitkovitch, with research associate Céline Lévesque, and MSc student Cathy Huang, began designing analogs or variations of the S. mutans peptides. After establishing the sequence of the native-21 amino acid CSP, the team was able to determine which amino acids could interfere with S. mutans but not activate it. "This showed that certain analogs were able to inhibit biofilm formation," says Cvitkovitch.

CSP is now being brought one step closer to the billion dollar oral care market through an exclusive licensing agreement by U of T's Innovations Foundation. Kane Biotech, a Winnipeg-based company which specializes in biofilm solutions for healthcare and industrial environments plans on bringing the plaque-inhibiting power of CSP to the marketplace in the form of toothpaste, chewing gum, bottled water and even dog biscuits.

- Maria Saros Leung

University of Toronto Office of the Vice-President, Research and Associate Provost