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Current Affairs

Water bears and lethal UV radiation

Date: 04 November 2020 Tags: Miscellaneous

Issue

Scientists have discovered a new species of water bear that can endure lethal ultraviolet (UV) light.

 

Background

Water bears can survive extreme heat, radiation, and even the vacuum of outer space, conditions that would kill most animals.

 

Details

  • Researchers at the Indian Institute of Science were looking for water bears to study and exposed them to extreme conditions.

  • The dose of UV light was lethal to Hypsibius exemplaris tardigrades at 15 minutes; most died after 24 hours.

  • But when the researchers hit a strange, reddish brown species with the same dose, all survived. When the researchers upped the dose four times, about 60% of the reddish brown bears lived for more than 30 days.

  • To find out how the new species survived, the scientists examined it with an inverted fluorescence microscope.

  • Under the UV light, the reddish tardigrades became blue. Fluorescent pigments, likely located under the tardigrades’ skin, transformed the UV light into harmless blue light.

  • Next, the researchers extracted the fluorescent pigments and used them to coat H. exemplaris and several Caenorhabditis elegans earthworms.

  • Animals with the modified shields survived at almost twice the rate of animals without the shields.

 

Water bears

  • Tardigrades known as water bears or moss piglets are a phylum of eight-legged segmented micro-animals.

  • They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them little water bears.

  • Tardigrades are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates.