Tardigrades These eight-legged marvels of survival are tiny aquatic invertebrates, also known as tardigrades. UV rays, The vacuum of space,and, Shot by a gunThe scientists 1400 species of tardigrades The creatures, which are collected from freshwater and marine habitats around the world, are seemingly indestructible and “The toughest animals on earth“But are they strong enough to survive on Mars?
Space agencies around the world are currently Sending humans to MarsBut life on Mars comes with its own environmental challenges: Researchers have shown that tardigrades can survive the radiation, extreme temperatures, dehydration and lack of oxygen that characterize the Red Planet. Studying Martian soil I realized it contained toxic salts. PerchloratePerchlorates dissolve rapidly in solution to form salt solutions or brineIt inhibits the cells' ability to retain moisture and produces reactive chemicals, such as hydrogen peroxide, which can damage cells. Oxidative stressScientists have found perchlorate concentrations in Martian soil as high as 0.6 percent, roughly 1,000 times higher than the highest concentrations found in Earth's desert soils.
Scientists have previously found that some soil bacteria can survive perchlorate using special enzymes that fight it and protect cells from oxidative stress. Unfortunately, animals lack these enzymes. Other researchers have found that tardigrades Paramacrobiotus experimentalis Can survive Short-term exposure Animals living on the Martian surface would be exposed to perchlorates for up to 24 hours, but animals living on the Martian surface would have to contend with these toxins indefinitely.
A team of Polish researchers recently tested whether tardigrades could perform this task. They Pam.Experimental The tardigrades were exposed to high concentrations of perchlorate, similar to those found in Martian soil, for eight weeks to see how long they would survive. The researchers reasoned that because this species of tardigrade can tolerate short-term exposure to perchlorate, it may be able to survive for longer periods of time.
The researchers: Pam.Experimental Tardigrades were collected from moss in Madagascar and fed a diet of earthworms and plankton. For each experiment, 24 newly hatched tardigrades were transferred to solutions containing 0.10%, 0.15%, 0.20%, or 0.25% magnesium perchlorate. As a control, another 24 were transferred to a solution without perchlorate. The tardigrades were kept in these solutions for 56 days in the dark, at 18 °C (approximately 64 °F) and 40% relative humidity. The solutions were changed every 7 days, and dead tardigrades were removed.
At the end of the experiment, the researchers Phase contrast microscopeThis type of microscope makes use of the fact that light waves change height and direction when they interact with an object. amplitudeand location, or stepThe human eye can see amplitude changes in brightness and color intensity, but not phase changes. Phase contrast microscopes convert invisible phase changes into visible brightness changes, allowing scientists to see fine details in transparent specimens like tardigrades.
The team counted live and dead tardigrades under a phase-contrast microscope and found that 83% survived on 0.10% magnesium perchlorate, compared with 87% in the control group. They also found that about 58% of the tardigrades survived on 0.15% perchlorate, 29% on 0.20% perchlorate, and 20% on 0.25% perchlorate. The team interpreted this trend as meaning that although more than 0.10% perchlorate is toxic to most tardigrades, some individuals can survive at about half the perchlorate concentration found on Mars.
The researchers also measured the body length of the surviving tardigrades, which were about two-thirds as long as those raised without perchlorate. The researchers suggested that tardigrades grow slower in the presence of perchlorate because the salt directly inhibits the tardigrades' growth or stops them from feeding.
These scientists demonstrated that tardigrades can survive Mars-like perchlorate levels for eight weeks, but did not reveal how they did this. They suggested that tardigrades must use a special technique to withstand the toxic perchlorate. Dry hibernation For example, when faced with high salinity or other extreme conditions. Damage suppressor proteins It protects them from radiation and helps them survive.
The team recommended that future researchers investigate whether tardigrades can survive and thrive when simultaneously exposed to perchlorate and other harsh conditions present on Mars. They also suggested that scientists study the biochemical pathways involved in tardigrades' perchlorate resistance to see if these pathways can be genetically engineered to confer perchlorate resistance to other animals that colonize Mars. One day, future humans may stroll under the Martian sky wearing tardigrade-reinforced skin.
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Source: sciworthy.com
