Drunken goldfish? According to new research, fish of the genus Carassius (crucian carp and goldfish) have evolved a set of enzymes that convert carbohydrates into alcohol when they are in low-oxygen water. Unlike all other fish, this mechanism allows them to survive in frozen ponds for many months at a time. Which explains how they can live in the lakes of northern Europe and Asia—the mystery which biomedical researchers at the University of Oslo and the University of Liverpool were investigating. When humans and most other animals' cells are deprived of oxygen, they can die within minutes. That's because when we metabolise carbohydrates without the help of oxygen—known as anaerobic metabolism—our bodies produce toxic lactic acid, which quickly builds up in our muscles and must quickly be removed by the liver (with the help of oxygen!). But in findings published this week in Nature, scientists discovered that when Carassius anaerobically metabolize carbohydrates, they produce alcohol instead of lactic acid. The fish then release the harmless alcohol through their gills. The fishes' secret evolutionary power stems from a set of enzymes which kick into action when their oxygen levels drop. These enzymes are almost identical to brewer's yeast, which is how beer is made from carbohydrate-rich grains! Scientists believe that Carassius evolved this alchohol-not-lactic-acid mutation around eight million years ago. To survive the oxygen-free or anoxic frozen lakes, the fish must generate so much alcohol that their blood alcohol level hovers around 55 mg per 100 mL for the entire winter. Ironically, that exceeds the drunk-driving limit in all of the northern European countries where it lives. No word on whether the drunken goldfish swim erratically or enjoy the experience.
I took this information from curious.com which is a website that I am a member of.
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