About My Health Careers Internship MedBlogs Contact us
Medindia LOGIN REGISTER
Advertisement

How Antarctic 'antifreeze Fish' Survives Icy Waters

by Rajashri on October 18, 2008 at 3:36 PM
Font : A-A+

 How Antarctic 'antifreeze Fish' Survives Icy Waters

Scientists have shed light on the adaptations that enable a fish to survive in one of the harshest environments on the planet in the icy waters of Antarctica.

The study is the first to search the genome of an Antarctic notothenioid fish for clues to its astounding hardiness.

Advertisement

There are eight families of notothenioid fish, and five of them inhabit the Southern Ocean, the frigid sea that encircles the Antarctic continent.

These fish can withstand temperatures that would turn most fish to ice. Their ability to live in the cold - and oxygen-rich - extremes is so extraordinary that they make up more than 90 percent of the fish biomass of the Southern Ocean.
Advertisement

Dissostichus mawsoni, the Antarctic toothfish, is the largest of the notothenioid fish to inhabit the Southern Ocean.

University of Illinois (U. of I.) animal biology professor Arthur DeVries discovered in the late 1960s that some notothenioids manufacture their own "antifreeze proteins." These proteins bind to ice crystals in the blood to prevent the fish from freezing.

In the new study, U. of I. animal biology professor C.H. Christina Cheng and her colleagues at the Chinese Academy of Sciences sought comprehensive genetic clues that would help explain how the Antarctic notothenioids survive.

Cheng and her colleagues wanted to know which genes were being expressed at high levels in one representative species of Antarctic notothenioid, Dissostichus mawsoni.

They analyzed gene expression in four tissues: the brain, liver, head kidney (the primary blood-forming organ in fish) and ovary of D. mawsoni.

"We saw this very peculiar profile where in each of these tissues the proteins that are highly expressed are from a small set of genes," Cheng said.

"Each tissue makes all kinds of transcripts - the genetic messages that are made into proteins - but we found that a small group of genes dominates the transcriptional process," she added.

The researchers reasoned that any proteins that gave the fish an advantage in a cold, oxygen-rich environment would be expressed at high levels in the Antarctic fish.

To get a better idea of whether the genes that were "upregulated" in D. mawsoni enhanced its survival in the Antarctic, the researchers compared gene expression in D. mawsoni and in the same tissues of several unrelated, warm-water fish.

They found that most of the genes that were highly expressed in the Antarctic fish were not elevated in the warm-water fish.

When they analyzed the upregulated genes, the researchers found that many of them coded for proteins that respond to environmental stress.

There were many chaperone proteins, including "heat shock proteins," for example, which protect other proteins from being damaged by stresses such as extreme cold or heat.

Source: ANI
RAS/SK
Advertisement

Advertisement
News A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Advertisement
News Category
What's New on Medindia
Turmeric: Magic Ingredient to Keep you Healthy in Winter
Top 7 Benefits of Good Oral Hygiene
Healthy and Safer Thanksgiving 2021
View all

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.


Recommended Reading
EEA Says Most EU Kyoto Signatories may Achieve Goals
The 15 European Union countries that signed up to the 1997 Kyoto agreement on cutting greenhouse ......
Global Warming Means More Sediment on Ocean Bed, Spelling Doom for Corals
Sediment on ocean bed could prove fatal for corals. And the sediment increases as global ......
Temperatures may be Raised If Air Pollution is Cleaned Up!
Cleaning air in large cities suffering from pollution problems by limiting car and power-plant ......

Disclaimer - All information and content on this site are for information and educational purposes only. The information should not be used for either diagnosis or treatment or both for any health related problem or disease. Always seek the advice of a qualified physician for medical diagnosis and treatment. Full Disclaimer

© All Rights Reserved 1997 - 2021

This site uses cookies to deliver our services. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use