Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Hibernation and Hypoxia

Comparative Physiologist listed among the 100 most influential people of 2020

I was very excited to see Comparative Physiologist and astronaut Jessica Meir listed among Time’s 100 most influential people of 2020. Together with astronaut Christina Koch, who was also named among the top 100, the astronauts performed the first all-female spacewalk at the International Space Station in 2019. In all, the pair completed three spacewalks while aboard the International Space Station. It is hard to imagine how challenging it must […]

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Researchers discover cause of hearing loss in an underground dweller

Naked mole rats are rather extreme animals in many ways. As underground dwellers, they live in chronically hypoxic environments and are blind. These animals also age more slowly than other mammals and are resistant to developing cancer even though they are long-lived. Did you also know, they are hard of hearing? In a new study published in Current Biology, researchers have discovered the cause of their hearing loss. The inner […]

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We all need to get some shut eye

I have to confess that I have been spending way too much time binge watching shows about sharks during this year’s Shark Week on Discovery Channel. I know I should be getting 7 hours of sleep a night…but could watching just one more show be that bad? Speaking of sleep, I am reminded of a study that I read awhile back examining whether sharks and rays need sleep. This may […]

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Avian red blood cells produce hydrogen sulfide to maintain cell integrity and longevity

Birds have strange red blood cells, at least in comparison to mammals. While they both are responsible for transporting oxygen molecules throughout the body, avian red blood cells have mitochondria and a nucleus. Mammalian red blood cells, on the other hand, are missing a nucleus as well as organelles. By eliminating these structures, mammalian red blood cells are able to carry more oxygen molecules and fold more easily to fit […]

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Hypoxia improves exercise duration

Speaking of hypoxia, a new study published in Physiological Reports examined how training for 2 weeks under 18% hypoxia impacts muscles of Thoroughbred horses. Unlike humans, these horses do not increase production of red blood cells to enhance oxygen transport throughout the body under hypoxic conditions. This difference led researchers to speculate that the horses had other ways of adapting to exercise.   In the new study, horses were trained […]

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Cholesterol levels in tissues change during hypoxia in naked mole rats

Naked mole rats are rather famous from a physiological perspective for their amazing ability to live in hypoxic conditions. They do so in part by reducing their metabolic rate. In fact, researchers at the University of Ottawa in Canada showed that reducing environmental oxygen levels to 11% resulted in a 34% decrease in the animal’s metabolic rate. Studies of hypoxia-tolerant goldfish show that the animals respond to hypoxia challenges by […]

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Physiology of diving animals: how do they deal with hypoxia?

Dr. Jose Pablo Vazquez-Medina (pictured at right), a comparative physiologist at the University of California – Berkeley, was scheduled to present several ongoing studies from his lab at the Experimental Biology conference last month. Dr. Vazquez-Medina is a member of the Comparative and Evolutionary Physiology section of the American Physiological Society. Although the conference was cancelled due to Covid-19, Dr. Vazquez-Medina has agreed to share his research with us.   […]

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How some fish may compensate for low environmental oxygen

     Adult fish rely on gills to extract oxygen from the surrounding water. Larval fish, on the other hand, do not have well-developed gills and instead rely primarily on gas exchange across their skin.      In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers examined whether larval fish could use their pectoral fins to increase the flow of water […]

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Warm hypoxic waters impair heart function in some fish

Events causing bodies of water to become hypoxic (low oxygen levels) are increasing with climate change. Water can become hypoxic when it warms up or there are changes in tidal flow, density, wind patterns as well as separation from the main source, such as occurs in a tidepool. While some fish are tolerant of hypoxia and even anoxia (oxygen depleted) environments others, such as Atlantic cod and steelhead trout, rely […]

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On the path to understanding the effects of white-nose syndrome

Molly Simonis and colleagues from Wright State University and Ohio University presented interesting research at the 34th annual Ohio Physiological Society conference on their work looking at the physiological effects of exposure to white-nose syndrome. White-nose syndrome is caused by the fungus Pseudogymnoascus destructans and has been blamed for killing millions of bats in North America. This new study seeks to examine whether pregnant female Eptesicus fuscus bats, a species less susceptible to […]

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