Targeting a signaling pathway in mice helped them retain muscle and bone mass aboard the International Space Station, according to a new study.
- Losing bone and muscle mass in space is a major health concern for astronauts.
- In a recent study, scientists genetically altered mice and sent them to the International Space Station.
- The genetically altered mice retained — or even gained — muscle and bone mass, while a control group suffered significant losses.
Comparison of bone density loss between the mice groups.
(Image credit: Se-Jin Lee)<p>Upon return to Earth, the untreated mice showed significant losses in muscle mass and bone density. But the mice missing the myostatin gene retained almost all of their muscle and bone mass. What's more, the mice that received the gene-inhibiting treatment actually gained bone and muscle mass. The researchers observed similar results among a separate group of mice that were given the same set of treatments on Earth.</p><p style="margin-left: 20px;">"These findings show that blocking the activities of these hormones does work to enhance both muscle and bone even when mice are unable to bear weight," study authors Se-Jin Lee and Emily L. Germain-Lee told <a href="https://www.cnn.com/2020/09/07/world/mighty-mice-space-station-study-scn-wellness-trnd/index.html#:~:text=The%20experiment%20was%20called%20Rodent,muscle%20mass%2C%20according%20to%20NASA.&text=Meanwhile%2C%20the%20untreated%20mice%20experienced%20significant%20muscle%20and%20bone%20mass%20loss." target="_blank">CNN</a>.</p><p style="margin-left: 20px;">"One thing that we found somewhat surprising is how resilient mice are even when subjected to all of the stresses associated with space travel. We knew that mice had been sent to space in the past, but we still found it remarkable that after spending a month at the ISS, they seemed to resume normal activity very quickly after returning to Earth."</p>
Pixabay<p>Treatments like these could protect astronauts on future long-term space missions. After all, studies show that spending just 16 to 28 weeks in space can cause a 3.5-percent loss in bone density, so space agencies are understandably concerned about the health risks of sending astronauts on a three-year mission to Mars.</p>
Applications on Earth<p>The researchers also noted that "this strategy may be effective in preventing or treating muscle and bone loss not only in astronauts on prolonged missions but also in people with disuse atrophy on Earth, such as in older adults or in individuals who are bedridden or wheelchair-bound from illness."</p><p>Still, the experiment was done on mice, so it's not clear whether the treatment would have the same effects on humans. It's also unclear what other side effects the treatment might have on humans. Answering these questions will take some time.</p><p style="margin-left: 20px;">"We're years away," Germain-Lee told <a href="https://phys.org/news/2020-09-mighty-mice-musclebound-space-boon.html" target="_blank">Phys Org</a>. "But that's how everything is when you go from mouse to human studies."</p>
Researchers think they know how a group of ancient sloths, who died thousands of years ago in Ecuador, met their untimely end.
- Evidence collected from an ancient boneyard in Ecuador suggests that a group of 22 ancient giant sloths died in a wallow of their own feces.
- Other mammals, such as a deer, a horse, an elephant-like creature called a gomphothere, and another species of ground sloth were identified at the site.
- The fate of the sloths parallels that of modern hippos who can become lethally poisoned in times of drought when the feces to water ratio shifts in their watering holes.
Discoveries from an ancient boneyard<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="0745aba719f914d2113ab181ef8201b8"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/vDCk0Uma2m4?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>An assemblage of 677 bones, 575 of which belonged to <em>E. laurillardi</em>, were found on this site in the Santa Elena peninsula in Ecuador. Other mammals, such as a deer, a horse, an elephant-like creature called a gomphothere, and another species of ground sloth were identified. Analysis of <em>E. laurillardi</em>'s bones reveal that the sloths likely died around the same time, evidenced by the lack of sediment separating them. They were also part of a multigenerational group, including at least 15 adults, one teen, and six children. This arrangement of remains and the range of ages indicates a mass mortality event, according to the researchers.</p><p>Giant ground sloths were once one of the most common large vertebrates living in the Americas. <a href="https://advances.sciencemag.org/content/5/2/eaau1200?rss=1" target="_blank">Prior research</a> indicates that the species, which can reach lengths of 19 feet, were widely distributed across the region ranging from southern Brazil to North America's Gulf and Atlantic coasts. We also know that they died out 11,000 years ago. But little has been known about their behavior and social structure, which is why this latest find is so exciting.</p><p>While modern sloths are solitary creatures, the paper suggests <em>E. laurillardi</em> were rather gregarious creatures who congregated near water. Tanque Loma was probably once a marshy watering hole where the sloths cooled off, bathed, and quenched themselves similar to warthogs and hippopotamus populations today. </p>
Clues point to a crappy death<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzI4MzE2My9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyODU1NzY3OX0.91lo89Xr_jBdsvWSkKTbHwNOJWv7jBnd7YuA4q6Z1_U/img.jpg?width=1245&coordinates=0%2C326%2C0%2C0&height=700" id="78782" class="rm-shortcode" data-rm-shortcode-id="daf9283b05bad90707373531acf5a906" data-rm-shortcode-name="rebelmouse-image" alt="pod of hippos" />
Photo Credit: Jeff Griffith / Unsplash<p>Prior analysis suggested that the asphalt on the site seeped into the sloths' gravesite after the bones had already been deposited, thus ruling out death by asphalt poisoning. Death by volcano or other natural disaster is also unlikely because the sediments do not contain ash or charcoal. And because the sloths across a full range of age groups are present, their death probably wasn't caused by disease or a predatory attack, either. In those cases, there would be an overrepresentation of old and young.</p><p>Rather, the researchers believe the sloths died another way.</p><p>"Taking observations from modern megafaunal ecosystems as an analogue, we suggest that this death event could have resulted from drought and/or disease stemming from the contamination of the wallow, paralleling situations observed among hippopotamus populations in watering holes on the present-day African savannah," write the researchers in the paper.</p><p>The scientists suspect that the fate of some hippopotamus groups may point to what happened to these 22 ancient giant sloths. Hippos are apparently <a href="https://www.sciencealert.com/hippopotamus-faeces-causes-water-hypoxia-kills-fish" target="_blank">prolific poopers</a>. So much so that the amount of their waste can change the chemistry of water they spend their days in to the point of sometimes killing all the fish. It can even, sometimes, kill the hippos in times of drought when the feces to water ratio shifts.</p><p>"Based on the data from this study, a modern analogue to the Tanque Loma <em>E. laurillardi</em> assemblage may be hippopotami, which congregate in large numbers at water sources where they spend most of their time submerged to protect themselves against heat, sun and insects," <a href="https://www.sciencedirect.com/science/article/abs/pii/S003101821930447X" target="_blank">the researchers wrote</a>. "In times of drought, as these water sources begin to dry up, surrounding vegetation disappears and the wallows become increasingly polluted with hippopotamus faecal material, causing significant detrimental impacts on the watershed ecosystem." </p><p>Besides bones, the team found plant material in <em>E. laurillardi</em>'s fossil bed. Interestingly, this was not living plant material—it had been digested and excreted. This supports the theory that the ancient sloths met their unfortunate demise in a slop of their own feces.</p>
Nuclear weapons, whale sharks, and how to use both to make eco-tourism more sustainable.
- Scientists have finally determined the age of whale sharks using radioactive elements from bomb tests.
- Using the new data, the age range of the animals' bones has now been determined.
- The findings will help conservationists better maintain whale shark populations.
Majestic whale sharks, the gentle giants of the shark family.<p>Weighing in at 9 tons (20,000 pounds) and typically growing to around 10 meters (32 feet) long, the <a href="https://en.wikipedia.org/wiki/Whale_shark" target="_blank">whale shark</a> is the largest living species of fish. Despite the name, it is not a whale, though it is the size of one. Like many kinds of whales, it filter feeds on plankton.</p><p>Many things about the whale shark have remained unknown to science; how long they can live, their mortality rate, and how exactly to determine the age of a specimen from its remains was chief among them. However, these questions are now a little closer to being settled. In a <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.00188/full" target="_blank">study</a> recently published in <em>Frontiers in Marine Science,</em> scientists explain how they were able to date the bones of two whale sharks who met their fate earlier than they may have expected. </p><p>Like trees, whale sharks' bones have growth rings. Scientists have known about these rings for a while, but how quickly the rings grow has been unknown. It is difficult to use them to estimate the age of a shark if you aren't sure how much time each ring represents.</p><p><br></p>
A whale shark vertebra from Pakistan, in cross section, showing 50 growth bands
Image: © Paul Fanning, Pakistan node of the UN Food and Agricultural Organisation<p>This is where carbon-14 comes in. As a result of nuclear bomb tests during the Cold War, large quantities of carbon-14 were put into the oceans. The isotope slowly made its way up the food web and into the bodies of larger animals. Knowing the yearly changes in the amount of carbon-14 in the oceans due to bomb testing, scientists merely had to compare that data with the changes seen in the sharks' bones.</p><p>"We found that one growth ring was definitely deposited every year," <a href="https://www.eurekalert.org/pub_releases/2020-04/aiom-cwn033020.php" target="_blank">said Dr. Mark Meekan</a> of the Australian Institute of Marine Science in Perth, a co-lead on the study. "This is very important, because if you over- or under-estimate growth rates you will inevitably end up with a management strategy that doesn't work, and you'll see the population crash." This means the sharks used in this study were around 35 and 50 years old at the time of their deaths.</p><p>Working forward from there, the scientists were able conclude that the animals may have an age range of 100-150 years. "Earlier modelling studies have suggested that the largest whale sharks may live as long as 100 years," Dr. Meekan explained in <a href="https://www.eurekalert.org/pub_releases/2020-04/aiom-cwn033020.php" target="_blank">a statement</a>. "However, although our understanding of the movements, behaviour, connectivity and distribution of whale sharks have improved dramatically over the last 10 years, basic life history traits such as age, longevity and mortality remain largely unknown. Our study shows that adult sharks can indeed attain great age and that long lifespans are probably a feature of the species. Now we have another piece of the jigsaw added."</p>
Your bones would "explode."
Who can forget the nail-biting scene in Jurassic Park when an escaped T-Rex, in the middle of a thunderstorm, proceeds to turn over and tear apart a Range Rover with two children trapped inside? Movie magic and real science don't often intersect. So, is this what would really happen, or is Hollywood just ramping up the drama? And how strong was a T. rex's bite anyway? Scientists now know. And the truth is, this terrifying predator retains its reputation. The jaw strength of a T-Rex contained nearly 8,000lbs (3,629kg) of force.