StemCell Therapy

The road to Batlow is full of dead.

In the gray, smoky mist of the morning, it is difficult to distinguish exactly what Matt Roberts' camera captures. Roberts, a graphic reporter for the Australian Broadcasting Corporation, keeps his lens focused on the road while rolling towards the devastated by fire 55 miles west of Canberra, the capital of Australia. On the edge of the asphalt, the blackened carcasses lie motionless.

The grim scene widely shared on social networks, is emblematic of the impact that the forest fire season 2019-20 has had on the animal life of Australia. Some estimates suggest that "many, billions" of animals have been killed, endemic insect populations could be crippled and, as the ashes go down to the waterways, marine life will be severely affected. The scale of forest fires is so large that scientists are unlikely to know the impact on wildlife for many years.

But even before wildfires roared across the country, the only animals native to Australia were in a terrible struggle for survival. Habitat destruction, invasive species, hunting and climate change have conspired against them. Native wildlife populations are plummeting or disappearing altogether, leaving Australia with an unenviable record: it has the highest rate of mammalian extinctions in the world.

A large part of the extinctions in Australia have involved marsupials, the kind of mammals that include kangaroos, wallabies, koalas and the nation's iconic wombats. A century ago, the Tasmanian Tiger He was still walking quietly through the forests of Australia. The desert rat kangaroo leapt through the clay containers inside, taking refuge from the sun in excavated nests.

Now they are gone.

Australia's 2019-20 forest fire season has been devastating for wildlife.

John Moore / Getty

In a search for answers to the extinction crisis, researchers are turning to a lesser-known species, small enough to fit in the palm of their hand: the fat-tailed dunnart. The mouse-shaped carnivorous marsupial, no bigger than a golf ball and almost as heavy as a toothbrush, has a small snout, dark, bulbous eyes and, as expected, a fat tail. Their Baby yoda adorable levels, and can be so influential.

The dunnart genome mapping could help this small animal to become the marsupial equivalent of the laboratory mouse, a model organism that scientists use to better understand biological processes, manipulate genes and try new approaches to treat the disease. The ambitious project, driven by the marsupial geneticist Andrew Pask and his team at the University of Melbourne over the past two years, will see scientists take advantage of the incredible feats of genetic engineering, reprogramming the cells at will.

It could even help the creation of a frozen Noah's ark of samples: a vault at the end of the world of marsupial cells, suspended in time, to preserve genetic diversity and help prevent further deterioration, returning species to the edge of the extinction

If that sounds exaggerated, it is not. In fact, it is already happening.

The creation of a reliable marsupial model organism is a long-standing dream for Australian geneticists, dating back to research initiated by the famous statistician Ronald Fisher in the mid-20th century. To understand why the model is so important, we must look at the laboratory mouse, a staple of science labs for centuries.

"A lot of what we know about how genes work and how genes work with each other, comes from the mouse," says Jenny Graves, a geneticist at La Trobe University in Victoria, Australia, who has worked with marsupials for five decades.

The mouse is an indispensable model organism that shares many genetic similarities with humans. It has been key in Understand basic human biology, try new medications and unravel the mysteries of how our brains work. Mice form such an important part of the scientific effort because they reproduce quickly, have large litters and are economical to house, feed and maintain.

The laboratory mouse has been indispensable for understanding physiology, biology and genetics.

Getty / Picture Alliance

In the 1970s, scientists developed a method to insert new genes into mice. After a decade of refinement, these genetically modified mice (known as "transgenic mice") provided new ways to study how genes work. You could add a gene, changing its expression to 11, or remove a gene completely, turning it off. The scientists had a powerful tool to discover which genes performed the critical work in reproduction, development and maturation.

The same capacity does not exist for marsupials. "At the moment, we have no way of manipulating genes in a demon, a kangaroo or an opossum," says Graves. Without this ability, it is difficult to answer more specific questions about marsupial genes and how they compare to mammalian genes, such as mice and humans.

So far, two species of marsupials, the Tammar wallaby and the American opossum, have been the focus of research efforts to create a reliable model organism, but both pose problems. The wallaby reproduces slowly, with only one baby every 18 months, and requires vast tracts of land to support itself.

Short-tailed possum could be an even more complicated case. Pask, the marsupial geneticist, says that the little South American marsupial is prone to eat his young, and the young requires researchers to examine hours of video, looking for who impregnated who. Pask also makes a patriotic jab ("they are Americans, so we don't like them") and says that their differences with Australian marsupials make them less useful for the problems facing Australian species.

But the dunnart has all the features that make the mouse such an attractive organism for the study: it is small and easy to accommodate, reproduces well in captivity and has large litters.

"Our little boys are like having a mouse basically, except they have a bag," says Pask.

Pask (front) and Frankenberg inspect some of their dunnarts at the University of Melbourne.

Jackson Ryan / CNET

A severe warning precedes my first encounter with Pask's fat-tailed dunnarts colony.

"It smells like shit," he says. "They shit everywhere."

I quickly discover that he is right. Upon entering the homes of the colony on the third floor of the utilitarian BioSciences building at the University of Melbourne, a musty smell and feces hit you in the face.

Pask, a relaxed investigator whose face is almost permanently fixed with a smile, and one of his colleagues, researcher Stephen Frankenberg, is not frightened by the smell. They have adapted to that. Inside the small room that houses the colony, the storage cages are stacked on three shelves high. They are full of cartons of overturned eggs and empty buckets, which function as makeshift nests for creatures to hide.

The dunnart will be our marsupial workhorse as the mouse for placental mammals.

Andrew Pask

Frankenberg approaches without hesitation and pulls one out of a cage, without a name but numbered "29", and hides in his clenched fist before peering through the space between his thumb and index finger, with his muzzle pressing. While I see Frankenberg cradling him, the dunnart seems curious, and Pask warns me that he is agile enough to make a great escape.

In nature, thick-tailed dunnarts are equally curious and floating-legged. Their range extends over most of southern and central Australia, and the most recent assessment of their population numbers shows that they are not suffering population declines in the same way as many of Australia's largest marsupial species.

Move aside, Baby Yoda.

Jackson Ryan / CNET

While I see 29 running around Frankenberg's arm, the physical similarities between him and a mouse are obvious. Pask explains that the DNA of the dunnart is much more related to the Tasmanian devil, a carnivore the size of an endangered cat native to Australia, than the mouse. But from a research perspective, Pask points out that the similarities between the mouse and the dunnart are deep, and that is why he is such an important creature.

"The dunnart will be our marsupial workhorse as the mouse for placental mammals," says Pask.

For that to happen, Pask's team has to perfect an incredible feat of genetic engineering: they have to learn to reprogram their cells.

To do this, they collect cells from the skin of the ear or the foot pad of the dunnart and place them in a flask where scientists can introduce new genes into the skin cell. The introduced genes can deceive the adult cell, convincing it to become a specialized "younger" cell with almost unlimited potential.

Reprogrammed cells are known as "induced pluripotent stem cells" or iPS cells, and since Japanese scientists unraveled how to perform this incredible feat in 2006, they have proven indispensable for researchers because they can become none cell in the body

"You can grow them in culture and put different types of differentiation factors on them and see if they can become nerve cells, muscle cells, brain cells, blood vessels," explains Pask. That means that these special cells could even be programmed to become a sperm or an egg, allowing embryos to occur.

Implanting the embryo in a surrogate mother could create a whole animal

It took about 15 minutes to make this dunnart stand still.

Jackson Ryan / CNET

Although there has been a great technological leap in mice, it is still a long way from fruiting the marsupials. Currently, only the Tasmanian devil has created iPS cells from the skin, and no sperm or ovules have been produced.

Pask's team has been able to trick dunnart cells into stem cells, and they have even made some slight genetic adjustments in the laboratory. But that is only the first step.

He believes there are likely to be small differences between species, but if the methodology is still consistent and reproducible in other marsupials, scientists could begin to create iPS cells from the unique Australian fauna variety. They could even take samples of wild marsupial skin cells and reprogram them.

Doing so would be indispensable in creating a biobank, where cells would freeze at -196 degrees Celsius (-273 F) and store until needed. It would act as a safeguard: a backup copy of the genetic material that could, in the distant future, be used to bring species back to the brink of oblivion, helping to repopulate them and restore their genetic diversity.

Under the Beckman Center for the Conservation Research of the San Diego Zoo is the Frozen Zoo, a repository of test tubes containing the genetic material of more than 10,000 species. Stacked in towers and refrigerated inside giant metal vats, the tubes contain the DNA of threatened species from around the world, suspended in time.

It is the largest wildlife biobank in the world.

"Our goal is to collect cells opportunistically in multiple individuals of as many species as we can, to provide a vast genetic resource for research and conservation efforts," explains Marlys Houck, curator of the frozen zoo.

The zoo's efforts to save the northern white rhino from extinction have been well publicized. Other research groups have been able to create a northern white rhino embryo in the laboratory, combining ovules from the last two remaining females with frozen sperm from deceased males. The scientists propose to implant these embryos in a surrogate mother of a closely related species, the southern white rhinoceros, to help drag the species towards the edge of oblivion.

For most of a decade, conservationists have focused on this goal, and now their work is paying off: in the "coming months," the northern white rhino embryo created in the laboratory will be implanted in a substitute.

Sudan, the last white rhino of the male north, was sacrificed in 2018.

Tony Karumba / Getty

Marisa Korody, a conservation geneticist at the frozen zoo, emphasizes that this type of intervention was really the last hope for the rhinoceros, a species whose population had already declined to only eight individuals a decade ago.

"We only resort to these methods when the more traditional conservation methods have failed," she says.

In Australia, researchers tell whoever hears that traditional conservation methods are failing.

"We've been saying for decades and decades, many of our species are on a slippery slope," says John Rodger, a marsupial conservationist at the University of Newcastle, Australia, and CEO of the Wildlife Research Alliance, who has long advocated time by the bank of species genetic material in Australia and New Zealand.

In October, 240 of Australia's top scientists delivered a letter to the government detailing the country's unfortunate history of species protection, citing 1,800 plants and animals in danger of extinction, and "weak" environmental laws that have not been effective in keeping Australian wildlife alive. .

Australian institutions, such as the Taronga Zoo and Monash University, have been samples of biobanks since the 1990s, which rely on philanthropic donations to stay online, but researchers say this is not enough. For at least a decade, they have been calling for the establishment of a national biobank to support threatened species in Australia.

No one in the world is working seriously on marsupials except us.

John rodger

"Our real problem in Australia is the lack of investment," says Rodger. "You have to accept that this is not a short-term investment."

The current government installed a commissioner of endangered species in 2017 and committed $ 255 million ($ 171 million in US dollars) in funds to improve the prospects of 20 mammal species by 2020. In the most recent progress report, published in 2019, only eight of those were identified that 20 had an "improved trajectory", which means that populations increased faster or decreased more slowly compared to 2015.

A spokesman for the commissioner described the $ 50 million investment to support immediate work to protect wildlife after forest fires, talking about monitoring programs, establishing "insurance populations" and traps for wild cats. No reference was made to future strategies regarding biobank.

Researchers believe that we must act now to preserve iconic Australian species such as koala.

Fairfax Media / Getty

Following the catastrophic season of forest fires and the challenges posed by climate change, Australia's extinction crisis is once again in the spotlight. Koalas are covered in social networks with charred noses and bandaged skin. On the front page of the newspapers, kangaroos tied in front of imposing walls of flame.

Houck notes that the San Diego frozen zoo currently stores cell lines "of almost 30 species of marsupials, including koala, Tasmanian devil and kangaroo," but that is only one tenth of the known marsupial species that live in Australia today in day.

"No one in the world is working seriously on marsupials except us," says Rodger. "We have a keen interest in keeping these guys for tourism, national icons whatever."

The researchers I speak with feel a growing sense of fear that perhaps we have passed a turning point, not only in Australia, but throughout the world. "We are losing species at an alarming rate," says Korody of the frozen zoo. "Some species are becoming extinct even before we know they are there."

With so much at stake, Pask and his dunnarts are in a race against time. Improving the techniques to genetically design the small cells of the marsupial will help allow the preservation of all species of marsupials for generations to come, future-proof against natural disasters, diseases, clearings and threats that we cannot even predict at this time.

Pask reasons "we owe it" to the marsupials to develop these tools and, at least, biobank their cells if we cannot avoid extinction. "We should really invest in these things now," he says. He is optimistic.

In the distant future, within years, a package of frozen stem cells could bring the koala or kangaroo back to the brink of extinction.

And for that, we will have the dunnart to thank.

Originally published on February 18 at 5 a.m. PT.

Here is the original post:
Build a & # 39; vault of the end of the world & # 39; to save the kangaroo and the koala from extinction - NewsDio

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