Category Archives: Ecology & Conservation (Core and Options)
Hybrid Hearts: Stem Cell Transplants 2.0
“Can we use stem cells to make a new heart/eye/lung/liver etc?”
This is the predictable and perennial question that comes up from at least one student when we are looking at stem cells, genetic engineering, cell differentiation and transplanting. Until now, the answer has (perhaps in an oversimplified way) been ‘no’.
We can use stem cell transplants to treat lymphoma. Recently a young woman had a trachea transplant based on stem cell technology. Skin grafts from a patient’s own cultured cells are also possible, as are stem cell-based bladders. However, these are all rather simple technologies.
To treat lymphoma, bone marrow cells are replaced, and are all the same. The trachea transplant was a pre-existing trachea simply coated in the patient’s stem cells to prevent immune rejection. Skin transplants are basically sheets of epidermis that cover a wound, yet do not have the intricate functions of original skin: temperature regulation, secretion, senses. The bladder is a bag.
The challenge with using stem cells to transplant a more complex organ, such as a heart, is that it is not a simple sheet made of one type of cell. It is complex 3D structure, with a range of cells performing specific tasks within the organ. These cells have differentiated to perform their functions: cardiomyocytes (beating cells), vascular endothelial cells (smooth internal surfaces) and smooth muscle cells (blood vessel walls).
How can we get the stem cells to become the right type of cell, in the right position?
The answer to this question could be the key to opening up new doors in the search for viable transplantable organs in medicine, and bears much in common with the trachea case. It also marks a return to form for the NewScientist YouTube channel, who have this short clip of the new hearts in action:
A full article to accompany the footage is here.
In a nutshell:
Decellularised pig heart: the scaffold (NewScientist)
1. Find a suitable transplant organ, such as a pig’s heart.
2. Strip of all cells and DNA, using a detergent. Only the collagen ‘scaffold’ remains, as in the image of the decellularised heart to the right.
3. Coat the scaffold with the recipient’s stem cells.
4. Ensure that the blood supply is adequate and will provide the right signals for differentiation.
What is amazing in this case is how the cells ‘knew’ what specialised cells to become. The leader of the research group, Dr. Doris Taylor, puts it down to the mechanical stimulus of the pressure of the blood in the vessels and chambers and chemical signals from growth factors and peptides that remained on the stripped heart structure.
They even went as far as replacing a healthy rat’s heart with one of these new hybrid hearts. The rat survived for the trial, but she says they need to focus on producing more muscular hearts in order to ensure long-term survival of transplant recipients.
Food for thought:
Read the whole article and some of the links within it. Discuss these questions:
1. What are the potential uses for this kind of transplant technology?
2. What are the current limitations of this method and how might they be overcome?
3. What are the ethical issues related to using hybrid (pig-human) organs in medical transplants? How would you feel if you were the patient?
4. Who are the various stakeholders in this technology and what are their viewpoints?
Useful Sources:
Dr Doris Taylor’s research page from the University of Minnesota
NewScientist Article: Hybrid hearts could solve transplant problem
BioAlive stem cells links and resources
Can stem cells repair a damaged heart? from the NIH
Research reveals how stem cells build a heart, from Harvard news.
Pandemic II: Educational Flash Game
Pandemic II: Spread the World
Thanks to the excellent NotExactlyRocketScience blog for posting the link to this game. Pandemic II is a complex flash game based on strategy, evolution (though more like design) and the spread of disease. The premise is simple – take a pathogen (bacteria, virus or parasite), and watch its spread across the globe. Along the way you can alter the pathogen to change its properties, making it more infectious, more lethal or less noticeable. The aim of the game is to wipe out the population of the world.
It is easy to save using Firefox add-ons.
Check out the game here: http://www.crazymonkeygames.com/Pandemic-2.html
And the tutorials here:
Is it better than the addictive Magic Pen Game or Foldit?
Have a go!
NOAA Environmental Visualisation Library
Education Resources, Animations, Videos and Satellite Images
Awesome. NOAA (National Oceanographic and Atmospheric Administration) has revamped its Environmental visualisation libray – bringing new educational materials, visualisations, animations and resources to educators and the public. See the images of the 2008 hurricane season, animations of the ocean damage caused by humans or check out their library of satellite images.
They also have a YouTube channel where you can view and download some of their video resources. In relation to our upcoming Earth Day theme of “Reefs and Oceans“, here’s a clip about the effects of coral bleaching:
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Check out the NOAA image galleries too...
How to regrow a rainforest – Willie Smits on TED Talks
Willie and the orangs
My Grade 12 class have looked at this story before, and now we can hear about it from Willie Smitts, a primatologist and conservationist who has led a huge project to replant and revive a section on rainforest in Borneo. They have taken over 8,000 hectares of scorched and cleared land and are returning it to a habitat worthy of orang-utans and many more endangered species.
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Smits was featured in TED2009 and here he is with his story of how they regrew the rainforest.
Microdocs: Stanford’s reef sustainability documentaries
Stanford’s Microdocs project is a well-presented set of video and pdf resources for learning about sustainability and the coral reef ecosystem. Each video is a few minutes long and accompanied by a short article or links to useful sources.
It’s divided into useful topics and easy to navigate (and looks good, too).
And while we’re on the theme of the oceans (again) there’s a brilliant student activity resource centre at the UCLA’s OceanGlobe centre. Everything you could ever need to study marine science.
The 11th Hour – Leo Dicaprio gets his Gore on…
Following on from Al Gore’s Inconvenient Truth, Leonardo DiCaprio last year released his environmental call-to-arms, The 11h Hour. And it’s very good. It really knocks home the old proverb that we are not inheriting the Earth from our ancestors, but borrowing it from our children.
Here’s the trailer:
The movie contains contributions from the likes of Stephen Hawking, Nobel-winner Wangari Maathai and David Suzuki. Particularly useful is Gloria Flora‘s sentiment that we all vote, every day – even those who are too young to cast a ballott – by making informed choices about what we consume, spend our money on and throw away.
The first half of the movie is a talking-heads and imagery look at our impacts on the Earth, with plenty of soundbites and starting-points for further discussion. There’s a poitical section in the middle that’s probably worth skipping, but the last section outlining some of the achievable solutions to our problems is excellent.
Now here’s Leo’s video message (including the ‘vote’ quote from Gloria Flora):
For some further reading, go to the 11th hour Action website, or check out An Inconvenient Blog.
For good measure, here’s Linkin Park’s accompanying music video, What I’ve Done (which was also used for Transformers):
Meet The Greens
Meet The Greens is a collection of animated webisodes featuring the Green family dealing with environmental Issues. Granny Green says blog it, so here we are! Go have a look.
Here’s their official blurb:
“MeetTheGreens.org is a new kids’ guide to looking after the planet. Kids can watch The GREENS’ cartoon adventures and discover related green games, news, downloads, a blog, action tips, links, and much more. This innovative, Web-only project comes from WGBH in Boston, the producer of shows like ZOOM, ARTHUR, Frontline & NOVA.“
ReefCheck – International Year of the Reef
2008 is International Year of the Reef (IYOR) and ReefCheck is an organisation devoted to monitoring and protecting the health of reefs around the world. As part of the IYOR activities, ReefCheck have released their Year of the Reef song, and you can see it on their site or on YouTube:
If you head over the to the ReefCheck.org website, you’ll find a wealth of great resources for education and action regarding the reefs. Particularly useful for students may be the WRAS (web reef advisory system), which is a collection of fact sheets on factors impacting reef ecology.
For people with a more active interest in the reefs (and for IB students interested in racking up some CAS credits), check out the EcoAction pages and see what is available there. You might want to get involved in the EcoMonitoring Program and take part in global reef research.
Also, if you hurry, you could get in on the action for the photo contest (closes 31st August).
One of the coolest things (for me, anyway) about ReefCheck is their presence on the Indies Trader, the vessel of the Quiksilver Crossing which is carrying world-class surfers around the globe searching for the best unsurfed waves on the planet. They also get to check out ‘untouched’ reefs in order to create a baseline against which they can compare the order of damage sustained by other reefs. To see some of their highlights, click here.
ActionFiguresTV has a tour of the Indies Trader here:
Now here’s Sebastian from the Little Mermaid singing the best Disney song ever:
The Great Turtle Race
Sea turtles make huge journeys across the Pacific, to and from egg-laying sites. Turtles laying eggs in Indonesia paddle (and use currents) all the way to California to forage for jellyfish, and leatherbacks from Costa Rica travel right down to the south Pacific.
Some researchers have been using GPS technology to track migrations to see if their route is the same each year:
There is even an annual event called The Great Turtle Race (this year is the second – The Olympiad!)
Head on over to their website to find out more about sea turtle conservation and visit some of their links.
There’s even a flash game or two to play, or a sea turtle survival lesson from Bridge: National Marine Educators Association
And, of course, there is a facebook group devoted to the race.
This is all organised by the leatherback trust.
i-Biology 