Opossums, Hydras And Hummingbirds: What We’re Learning About Aging From Animals – OPB News

The hydra, a tiny sea creature, appears to never age. Scientists are studying it to learn what secrets it may hold to longevity.

Leonardo Santamaria for NPR

A stint as lion tamer in Hollywood got Steven Austad interested in animal biology. And soon he turned from training animals to studying them. Hes now chair of the biology department at the University of Alabama at Birmingham, where his research focuses onaging.

Hes learned that aging happens at different rates in different animals, without following any clear rules. Austad says its not heart rate that predicts lifespan. An animals size has something to do with it, but some animals defy that pattern. And even more perplexing are animals that dont seem to age at all like a tiny sea creature called ahydra.

Austad spoke with Invisibilias Lulu Miller to discuss what science has uncovered about animal aging processes, and how researchers might be able to use what theyve learned to extend human lifespans. Theres no immortality on the horizon or anything close to it but its likely science can eventually lengthen our lives by at least a little, Austadsays.

This interview has been edited for clarity andlength.

How did you go from lion taming for the movies to studyingaging?

I was a reporter for the Oregonian newspaper in Portland. And a friend of mine had a couple of African lions for pets, because he was crazy. He got an offer to use them in a movie, and he needed somebody to help him transport them from Portland to Hollywood. And he talked me into helping out. When I got down there, the movie producer offered me a job and I said, You understand I dont know anything at all about this, right? And he said, thats okay. It awakened my interest in animals and what makes animals tick. After I got fairly seriously injured one time, I thought maybe this is not really what I want to do the rest of my life. So I decided to study animals in graduateschool.

What did you like about traininglions?

What I liked the most about lions is because they live in social groups, they like contact. Theyre almost like dogs, more like dogs than cats, except they sometimes will try to kill you. But I just love the intimate contact with them. For the first year, I never took a day off. I worked seven days aweek.

How did opossums short life span get you interested inlongevity?

We were working on some animals in South America opossums. I discovered that they age really quickly, almost like mice. And that was so puzzling to me that I completely abandoned what I was working on. It was the size and the longevity combination. I think we all have this kind of intuitive feel from being around animals that smaller animals are going to [have] shorter lives. So you know, a dog has a longer life than a mouse, and a horse has a longer life than a dog, and an elephant has a longer life than a horse. And this just seemed to grossly violate that. I had to recapture them every month, and I would come upon one that was in prime physical health, and two months later it would have cataracts, and it would have lost muscles, and had parasites all over it, and arthritis. It all happened soabruptly.

So, are size and lifespan linked in animals ornot?

Yeah, its a very general pattern. Its true of mammals. Its true of birds. Its true of reptiles. Its true of almost every group of animals. We know that smaller ones are shorter-lived and bigger ones are longer-lived. But there are exceptions, and actually I think the exceptions are the ones that are most interesting from a scientificperspective.

What is the billion beats hypothesis and why do you questionit?

Ive spent a good deal of my career trying to kill it, but obviously, I havent been able to. The [idea] is that life is inherently destructive and that burning energy is inherently destructive. Lets say all mammals have a kind of a fixed amount of energy that they can burn over the course of a lifetime. And if they burn it fast, theyll be short-lived, like mice. And if they burn it slow like an elephant, they can live much longer than that. The reason that I dont really buy it, is that if you actually look at a whole bunch of animals, it turns out that smaller ones actually have more heartbeats and use more energy over the course of a lifetime than large ones. And then there are these massive exceptions to it. Hummingbirds have a heart rate of over 1,200 beats per minute, which is kind of like a machine gun, but yet they can live in the wild into theirteens.

How do you think we should look at the link between size andlifespan?

I have developed something called the longevity quotient, which really is a way to say: Is an animal long-lived or short-lived for its size? Dogs, for instance, have a longevity quotient of one, which means theyre exactly an average mammal in terms of how long they live. And we have a longevity quotient of about four and a half, so we live about four and a half times as long as a mammal of our size should live. Mice live about 70% as long as an average mammal of thatsize.

And theres a very small animal thats actually one of the longest lived creatures,right?

Hydras were discovered actually in the early 1700s by Van Leeuwenhoek, who invented the first decent microscope. Theyre freshwater animals, maybe a quarter to a half inch in length. They almost look like a sea anemone, theyre just smaller and skinnier. They really started to be studied in earnest a few years later by a Swiss biologist named Trembley who discovered if he cut them in half across the middle, the bottom would grow a new top, and the top would grow a new bottom. It turns out that you can even treat them with chemicals that basically dissolve all the things that make their cells stick together. Youd make a pile of cells and they will eventually reassemble into a hydra. He started chopping them up in all kinds of ways to see exactly what you needed to regenerate. He eventually created a hydra that had multiple heads. Thats how it really came to be [called a] hydra, because a hydra in Greek mythology was this monster that had manyheads.

And what did we learn about aging from the hydra? How is it even possible for them to have this kind oflongevity?

Hydras have stem cells in them. When they divide, one half of it remains a stem cell, but the other half will eventually turn into part of the tentacle or part of the mouth or part of the body wall. It changed the way we thought about animal development at that point in time. We didnt really know how animals develop [in the 1700s], and one idea was that animals were just very, very tiny replicas of themselves when they were in an embryonic stage, and that pre-formed thing just grew. At that point they thought, maybe inside of a human egg theres a little tiny human and it hatches out into a baby and then it just grows and grows and grows. The hydra pretty much killed that idea because we could take just part of it, which clearly did not contain a whole hydra, and grow a whole new hydra out ofit.

Are hydras reallyimmortal?

Rumors really started to accumulate in the 1950s. People had followed individual hydras for a few years, and they didnt seem to die at any higher rates. So there was a rumor that they might be potentially immortal. Daniel Martinez in the late 1990s actually reported that they didnt age. Few people believed him. At least for as long as anybodys had the patience to follow individual hydras that has been about seven years at the most theres no indication that they age at all. It is possible that if we followed them long enough, we would discover that they aged, but no one has had the patience to do it. Certainly it would be a very, very long time. Theyre not the only animal that doesnt age, but theyre one of the few, and the others that dont appear to age are really close relatives the various kinds of jellyfish, forinstance.

What has been unlocked in the science of aging by looking athydras?

So the idea that if you manipulate single genes, it can have a dramatic effect on aging was really discovered in the late 1980s I would say. And then through the 90s it was confirmed and other genes werediscovered.

One of those genes directly interacted with this gene FOXO. Finding this in everything from little worms to people [with long lifespans] suggested that the activity of FOXO might be a key to understanding slow aging. So the hydra work really confirmed what had been seen in a number of otheranimals.

How has research on slowing agingprogressed?

Starting about 30 years ago, people discovered that there were genes that if you either knocked down their activity or souped up their activity could really have a major impact on aging. We started to look at drugs that could affect aging, and we now have at least half a dozen drugs that we know affect aging in a lot of different animals. Some of those things will turn out not to work in humans, but Im quite confident that we will develop ways to improve human health either by injections, by transfusions, by taking certain pills every day. And thats what the biotech industry is going nuts with rightnow.

You often hear people fantasize that were going to live 500 or 1,000 years in the future, and I dont buy that at all. We havent been able to do that with different species. What we can do is we can increase the longevity of mice, worms and flies lets say by 20% many, many ways. And so I think thats a reasonable idea. Whats unclear is how much of that will be healthylife.

Are there drawbacks to potentially extendinglifespan?

Lets imagine that we discover a gene mutation that doubles lifespan. If this is so great, why didnt nature do this a long time ago? If it has an effect on reproduction or the [time] to sexual maturity, it may turn out from an evolutionary standpoint not to be a good gene, but to be a bad gene. For all of the benefits that we get in terms of health, there may be some downsides to some of these treatments. We need to becareful.

Knowing everything you do about aging, do you live anydifferently?

I dont take anything. I dont do any weird diets. I do a lot of sensible stuff. I exercise a lot. I eat right. I dont smoke. Once theres enough evidence, I may try some other stuff. I dont think theres evidence enough in humans to be doing anything else right now.

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Opossums, Hydras And Hummingbirds: What We're Learning About Aging From Animals - OPB News

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Embryonic Stem Cell – Definition and Uses | Biology Dictionary

Embryonic Stem Cells Definition

An embryonic stem cell is a cell derived from the early stages of an embryo which is capable of differentiating into any type of body cell. Embryonic stem cells are capable of differentiating into any cell type because in the embryo that is what they are used for.

As the embryo grows and divides, cells which are generalized must become more and more specific as they divide. This eventually creates the different organs, tissues, and systems of an organism. Embryonic stem cells are totipotent,meaning they can divide into any other cell type within an animal. This is a process known as cellular differentiation.

After the sperm reaches an egg (oocyte), fertilization occurs and the DNA from the two cells merge into a single nucleus, in a single cell. This is the zygote and is technically an embryonic stem cell because as it divides it will differentiate into all of the cells of the body.

This cell and the first few divisions of this cell have the ability to become any type of tissue. This means that they have the ability to become an entire organism. Identical twins, for example, develop from the same zygote which accidentally separates when it begins to divide.

In medicine and research, scientists use pluripotent embryonic stem cells. These cells do not have the ability to become an entire organism. Rather, they are directed by signals from the early embryo which tell them which cell type to differentiate into. Scientists prefer these cells for many reasons.

First, they can be stored and maintained more easily. Totipotent cells have a tendency to differentiate quickly, and immediately try to become an organism. Pluripotent cells are waiting for a signal to divide and can be maintained for longer periods. Further, because pluripotent cells are simply waiting for the proper signals to tell them which cell type to become, they can easily be integrated into medical applications in which new tissue must be grown.

The use of embryonic stem cells is a very new form of medicine. For decades, the cause of many degenerative diseases and physical injuries has been understood. Tissue damage is the root cause of many of these ailments, and scientists have long been searching for a method of growing tissues which do not easily repair themselves. Because an embryonic stem cell is pluripotent and can become almost any cell in the body, these cells have long been studied for their possible use in medicine.

Since the late 1950s scientists have been trying to test various methods of growing tissue with an embryonic stem cell. The first clinical trials were in the late 1960s, but not much progress has been made. President Bush put a moratorium on using Federal funds for stem cell research, which was finally lifted by the Obama Administration in 2009. European countries have also faced an uphill battle in funding stem cell research. However, with advances in the science came new discoveries which allowed for more ethical harvesting of an embryonic stem cell. The first treatments with medicinal stem cells were in 2010.

Medically, the embryonic stem cell is limited in its current uses, though many novel applications are in the works. Current treatments focus on the replacement of damaged tissue from injury or disease. Of these, the first treatment approved by the FDA to undergo trials was replacing damaged tissue in spinal injuries.

Because nerve cells rarely regenerate, an embryonic stem cell can be used to replace the damaged nerve and restore function. In someone with a spinal injury, this means being able to walk again. For a blind person, this might mean being able to see again. While the treatment is still new and success is limited, it has shown some positive results.

Still, other medical advances are made with the embryonic stem cell, although these dont come as direct medical treatments but rather as the knowledge that stem cells give us. As an embryonic stem cell differentiates into its target tissue, scientists can study the chemicals and methods it uses to do so. Scientists can also alter the genome of these cells, and study the effects different mutations have on a cells functioning.

Between these two paths of discovery, scientists have assembled much information about how and why cells differentiate and divide. Using these tools, scientists are closing in on methods which would allow them to turn regular cell back into a pluripotent stem cell. These are known asinduced pluripotent stem cells. They are not embryonic stem cells, because they are not derived from an embryo. This process could not only fix injuries and ailments but could potentially reverse aging and prevent death.

On a less dramatic and grand scale, these methods are also being used to cure common diseases, such as diabetes. By learning how embryonic stem cells become pancreas cells and secrete insulin, scientists are learning the methods of converting other tissues to insulin-secreting tissues. This could help cure diabetes, often caused by the destruction of insulin-producing cells. If these were replaced with stem cells, or other cells were induced to become pancreas cells, the disease could be cured.

Other diseases, like cystic fibrosis, fragile x syndrome, and other genetic disorders are studied in embryonic stem cells. Not only can many cells be created, but they can be differentiated into different cell types. In this way, a scientist can build a picture of the disease from snapshots of each cell type, and understand exactly how the disease is affecting a person.

While there was once a concern that embryonic stem cells were being harvested without consent from unknowing women, the vast majority are now ethically harvested an in vitro fertilization clinics. In these clinics, in order to get a successful pregnancy, many eggs must be fertilized. Only one is implanted, and with the womans consent, the rest can be used to harvest embryonic stem cells. To do this, scientists extract some embryonic stem cells from an embryo when it is only a small ball of cells. This can be seen in the image below.

A harvested embryonic stem cell is placed in a petri dish with nutrients and is allowed to divide. Without any signals from the embryo, the cells remain pluripotent. They continue dividing, fill one dish, and they are transferred to many more dishes and continue to grow. After 6 months of this, they are considered a successful pluripotent embryonic stem cell line. They can then be used to study disease, be used in treatments, or be manipulated genetically to provide models for how cells work.

To test that these cells are indeed pluripotent stem cells, they are injected into mice with depressed immune systems. The mice must have depressed immune systems, or their bodies would naturally reject the human tissue. Once implanted into the mouse, successful pluripotent cells will form a small tumor called a teratoma. This small tumor has different tissue types and proves that the cell line is still pluripotent and can differentiate into different cell types.

There are also other types of stem cells, not to be confused with an embryonic stem cell. Embryonic stem cells are derived from embryos. There are also adult stem cells, umbilical cord stem cells, and fetal stem cells. Not only are these stem cells sometimes more ethically challenging, they are only multipotent, meaning they can only become a small range of cell types.

One example is umbilical cord blood stem cells, which have been used in medical treatments to treat various blood diseases and suppressed immune systems. The stem cells in the blood of the umbilical cord can differentiate into almost any type of blood or immune cell, making them multipotent. However, this limits their use in other areas of medicine.

There are also adult stem cells, which survive in various organs throughout the body. These cells are also multipotent, and can only differentiate into the kinds of tissue in which they are found. A common use of adult stem cells is the bone marrow transplant. In this procedure, a healthy donor must have their marrow extracted from their bones. The marrow is a blood-like substance on the inside of large bones which creates blood cells and immune cells.

Cancer patients, having undergone radiation and chemotherapy, lose most of their immune cells and become immunocompromised. Often a bone marrow transplant is needed to replace these tissues. The new stem cells begin producing new immune cells, which help the patient recover and fight off infection and disease.

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Pune to host fifth edition of global Drosophila conference – The Hindu

The city is set to host the fifth edition of the Asia Pacific Drosophila Research Conference (APDRC5), which is being organised in the country for the first time by the Indian Institute of Science Education and Research (IISER).

This biennial conference, which is to be held between January 6 and 10, aims to promote the interaction of Drosophila researchers in the Asia-Pacific region with their peers in the rest of the world. It will bring together scientists from all over the world who use the fruit fly, Drosophila, as a model organism to address basic and applied questions.

Drosophila is one of the most widely-used and preferred model organisms in biological research across the world for the last 100 years. Several discoveries in biology have been made using this. Its genome is entirely sequenced and there is enormous information available about its biochemistry, physiology and behaviour, said professor (biology) Sutirth Dey of IISER.

The event will feature 430 delegates: 330 Indian and 100 foreign. It will see the participation of two Nobel laureates, professors Eric Wieschaus and Michael Rosbash, known for their seminal contribution to the fields of development biology and chronobiology respectively.

Prof. Wieschaus, an American evolutionary developmental biologist, shared the Nobel in Physiology in 1995 with Edward B. Lewis and Christiane Nsslein-Volhard for his work on genetic control of embryonic development, while Prof. Rosbash shared the Nobel in 2017 in Physiology along with Michael Young and Jeffrey Hall for their discoveries of molecular mechanisms controlling the circadian rhythm.

This event is one of the largest meetings of Drosophila researchers in the whole world and attracts scientists working in diverse disciplines ranging from cell and molecular biology to ecology and evolution, said Prof. Dey.

Explaining the choice by the APDRC board of IISER to organise the meet, he said the institute is one the premier scientific research institutes of the country and is very strong in Drosophila research, given that there are five professors and 30 Ph.D. scholars who were using Drosophila to answer questions in developmental biology.

A total 57 talks and 240 posters on topics ranging from gametogenesis and stem cells, morphogenesis and mechanobiology, hormones and physiology, cellular and behavioural neurobiology, infection and immunity and ecology and evolution are scheduled for the conference.

One of the highlights of this conference is that we are explicitly encouraging undergraduates from various institutes of the world to participate in it. There is a pre-conference symposium called signals from the gut in collaboration with the National Centre for Cell Science, as well as a pre-conference microscopy workshop on super-resolution microscopy. This will feature microscopes from fluorescence imaging to super resolution imaging (50 nm resolution) which are vital for certain kinds of fly work, Prof. Dey said.

The last four editions of this conference took place in Taipei, Seoul, Beijing and Osaka.

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Pune to host fifth edition of global Drosophila conference - The Hindu

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