Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Extreme Animals

Ammonia tolerance of goldfish

Liver failure or congenital defects can lead to a build-up of ammonia in the brain of mammals resulting in life-threatening swelling, convulsions and comas. For goldfish (Carassius auratus), environmental exposure to ammonia causes reversible swelling of the brain. In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers wanted to explore how the fish were able to accomplish this. They exposed goldfish to high […]

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Reindeers may pave way for discovery of nerve regeneration techniques for humans

I came across a neat article in Scientific American that described how reindeer and elk regrow their antlers every year. Could you imagine putting that much energy into growing new bone each year complete with a velvety cover containing nerves, skin, and blood vessels? Although full-grown antlers lose their blood supply and animals scrape the velvet layer off to reveal just bone. Researchers have explored whether understanding this amazing process of […]

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Amazing longevity of Greenland sharks

A multi-national team of scientists sought to determine the age of Greenland sharks (Somniosus microcephalus). These animals grow rather slowly (about 1cm per year) and are the largest fish in the arctic (>500 cm long), but their longevity was not yet known. The team used radiocarbon dating of crystalline proteins found within the nuclei of the eye lens. Because these proteins are formed prenatally, they offer a rather accurate way to […]

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Extreme Physiology: Radiation Tolerance

  Don’t let their small size fool you. Tardigrades, or ‘water bears’, are really tough animals. According to a review published in the American Scientist, these microscopic invertebrates can survive extreme variations in temperature from near absolute zero (-459 deg F) up to +302 deg F. They can also tolerate pressures that are 6 times greater than the deepest ocean, exposure to ionizing radiation (UV and x-ray) and the vacuum of space, as well as exposure to […]

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Frigatebirds and lambs

I was checking out the award-winning American Physiological Society’s I Spy Physiology blog and came across a couple of really interesting posts about animals: “If Only Birds Could Compete in the Summer Games” This post reported a study of how frigatebirds manage to sleep during flights out at sea that can last for weeks. By measuring brain activity, the research team found that the birds were capable of actual sleep, during which time both […]

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Secret to safer stem cell therapy or cure for cancer?

Researchers trying to find cures for cancer find naked mole rats rather interesting. Not only are these animals long-lived by rodent standards, they are also resistant to the development of cancer. By long-lived, we are talking up to 30 years! A team of researchers from Hokkaido University and Keio University in Japan have now isolated stem cells from the skin of naked mole rats and induced them to revert back to pluripotent stem […]

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Keeping arteries healthy, lessons from seals?

Heart rate decreases during diving in seals and other animals. Thus the ascending aorta becomes very important during diving as it helps to maintain blood pressure during prolonged dives. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology was designed to examine the ascending aorta of hooded seals (Cystophora cristata) and the tiny blood vessels that supply nutrients to it, called the vasa vasorum. The […]

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Big-brained birds

Birds get such a bad rap when it comes to intelligence. Sure they have relatively small brains, but scientists have known they are similar to primates with respect to their cognitive abilities. New research published in the Proceedings of the National Academy of Sciences presents data showing how this apparent dichotomy is possible. They found that the brains of songbirds and parrots pack two times the number of neurons as a primate […]

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Limb regeneration in brittle stars

A new study published in Frontiers in Zoology examined the developmental process involved in regulating limb regeneration in brittle stars (Amphiura filiformis) following amputation of an arm. Limb regeneration is a multi-stage process involving initial healing and repair of the wounded site, initial growth of the limb followed by development of more complex layers of cells until ultimately the limb has been fully regenerated. Understanding this process in brittle stars may lead to […]

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Experimental Biology – Day 3

I LOVE THIS MEETING! DAY 3 included several very interesting comparative physiology sessions. Eldon Braun (University of Arizona) spoke about how birds have a unique way to prevent water loss and thereby dehydration. In mammals, the kidneys are responsible for recovering water from the urine. However when birds are well-hydrated, the urine enters the colon and moves backwards up the gastrointestinal tract to facilitate water reabsorption prior to voiding the […]

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