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How lizards regenerate their tails: researchers discover genetic 'recipe'


August 20, 2014

By understanding the secret of how lizards regenerate their tails, researchers may be able to develop ways to stimulate the regeneration of limbs in humans. Now, a team of researchers from Arizona State University is one step closer to solving that mystery. The scientists have discovered the genetic “recipe” for lizard tail regeneration, which may come down to using genetic ingredients in just the right mixture and amounts.

An interdisciplinary team of scientists used next-generation molecular and computer analysis tools to examine the genes turned on in tail regeneration. The team studied the regenerating tail of the green anole lizard (Anolis carolinensis), which, when caught by a predator, can lose its tail and then grow it back. green anole lizard (Anolis carolinensis) Download Full Image

The findings are published today in the journal PLOS ONE.

"Lizards basically share the same toolbox of genes as humans," said lead author Kenro Kusumi, professor in ASU's School of Life Sciences and associate dean in the College of Liberal Arts and Sciences. "Lizards are the most closely-related animals to humans that can regenerate entire appendages. We discovered that they turn on at least 326 genes in specific regions of the regenerating tail, including genes involved in embryonic development, response to hormonal signals and wound healing.”

Other animals, such as salamanders, frog tadpoles and fish, can also regenerate their tails, with growth mostly at the tip. During tail regeneration, they all turn on genes in what is called the 'Wnt pathway’ – a process that is required to control stem cells in many organs, such as the brain, hair follicles and blood vessels. However, lizards have a unique pattern of tissue growth that is distributed throughout the tail.

"Regeneration is not an instant process," said Elizabeth Hutchins, a graduate student in ASU's molecular and cellular biology program and co-author of the paper. "In fact, it takes lizards more than 60 days to regenerate a functional tail. Lizards form a complex regenerating structure with cells growing into tissues at a number of sites along the tail.”

"We have identified one type of cell that is important for tissue regeneration," said Jeanne Wilson-Rawls, co-author and associate professor with ASU’s School of Life Sciences. "Just like in mice and humans, lizards have satellite cells that can grow and develop into skeletal muscle and other tissues."

"Using next-generation technologies to sequence all the genes expressed during regeneration, we have unlocked the mystery of what genes are needed to regrow the lizard tail," said Kusumi. "By following the genetic recipe for regeneration that is found in lizards, and then harnessing those same genes in human cells, it may be possible to regrow new cartilage, muscle or even spinal cord in the future."

The researchers hope their findings will help lead to discoveries of new therapeutic approaches to spinal cord injuries, repairing birth defects and treating diseases such as arthritis.

The research team included Kusumi, Hutchins, Wilson-Rawls and Alan Rawls, as well as Dale DeNardo from ASU School of Life Sciences; Rebecca Fisher from ASU School of Life Sciences and the University of Arizona College of Medicine Phoenix; Matthew Huentelman from the Translational Genomic Research Institute; and Juli Wade from Michigan State University. This research was funded by grants from the National Institutes of Health and Arizona Biomedical Research Commission.

ASU’s School of Life Sciences is an academic unit of the College of Liberal Arts and Sciences.

Sandra Leander

Manager, Media Relations and Marketing, School of Life Sciences

480-965-9865

ASU professor studies impact of increased sugarcane production


August 20, 2014

The growing demand for bioethanol fuel, combined with a growing demand for sugar, means that sugarcane is being grown in increasing quantities around the world.

In some countries, lands previously used for subsistence agriculture are being converted to large industrial-scale sugarcane fields. In other countries, cane fields are replacing native vegetation. sugar cane field Download Full Image

“The transition from diverse vegetation to vast fields of a single crop is likely to have many impacts,” explains ASU professor Matei Georgescu, who will be investigating these impacts as part of a team of researchers from the United Kingdom, the United States, India, Brazil, South Africa and Australia.

In addition to changes in land-use and the ecology of agricultural lands, the transition to sugarcane in some places impacts food security – the availability of food to local residents. Large-scale mono-crop agriculture can affect everything from water supplies to disease control to soil nutrient cycles.

Climate change adds another element to this picture. Rainfall variability is likely to increase, making it unreliable as a source of water for the cane fields, and increasing the demand for irrigation.

Given the complexity of the environmental and human impacts of sugarcane agriculture, one of the goals of the two-year investigation is to encourage transdisciplinary investigation. The team includes experts in agricultural systems, land use modelling, social science, climate impact assessment, rural resource economics, GIS, remote sensing and spatial modeling for decision-making.

As they work together to understand the impacts of cane production’s expansion, the researchers aim to foster a community of scientists that will continue to develop a holistic understanding of agricultural change and its social and environmental consequences.

Georgescu will bring to the group his expertise in the climate impacts of land use change. A recent project modeled regional climate changes that may be expected as Brazil increases land in sugarcane production. Georgescu is also using regional climate models in another project, seeking to identify suitable locations across the United States where perennial biomass energy crops can be grown sustainably.

“Our ongoing bioenergy-related work in the United States is a natural springboard for this current project, which is primarily focused on networking and community building in the areas undergoing these land use transitions, and which therefore require the greatest attention,” says Georgescu.

The new project will focus on Brazil, India and South Africa, where agriculture is an important cornerstone of the economy, a basis of economic growth and a significant source of livelihood. These countries are also under pressure to improve resource efficiency and increase resilience to future climate uncertainty.

The project is funded by the Belmont Forum, a group of representatives from major funding agencies across the globe, including the National Science Foundation. More information about the project is available on the Belmont Forum’s website.

Matei Georgescu is an assistant professor in the School of Geographical Sciences and Urban Planning, an academic unit of the College of Liberal Arts and Sciences, as well as a senior sustainability scientist in the Julie Ann Wrigley Global Institute of Sustainability.

Barbara Trapido-Lurie

research professional senior, School of Geographical Sciences and Urban Planning

480-965-7449