Adult fruit flies (Drosophila melanogaster) are more tolerant of environments devoid of oxygen than their larvae. In fact, they are able to survive up to 12 hours without oxygen by becoming paralyzed, which enables them to dramatically reduce metabolism and the need for oxygen. In contrast, Drosophila larvae expend a lot of energy trying to escape and are only able to tolerate a couple of hours without oxygen. This is surprising […]
The plateau zokor (Eospalax baileyi) is an underground dwelling rodent species native to the Tibetan plateau (2000-4200 meters in elevation). A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology explored how these animals were adapted to extract oxygen from an environment with very low levels (83-88% of atmospheric). Hemoglobin molecules found in red blood cells are responsible for binding oxygen and transporting it to tissues […]
Animals that live at high altitude have evolved a number of physiological adaptations to deal with the low atmospheric oxygen concentrations (hypoxia). For low altitude acclimated animals, short exposures to high altitude results in activation of the sympathetic nervous system (i.e. the fight or flight response). This is a good thing because activation of this system results in more blood flow, especially to the heart and brain to help protect oxygen […]
In case you missed Shark Week this year, I thought I would mention a cool fact about dogfish sharks (Squalus acanthias) that you probably did not learn about. I read an interesting article from a lecture given by Dr. John N Forrest Jr, M.D. that was published in 2016 in Transactions of the American Clinical and Climatological Association. Sharks have a complicated system for regulating water and salt balance in the […]
In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers examined how changes in metabolism during torpor are regulated in 13-lined ground squirrels (Ictidomys tridecemlineatus). During hibernation, these animals cycle between bouts of torpor (about 2 weeks each) when their metabolism is reduced by 95% and body temperature can drop to 5degC and short states of interbout euthermia when both temperature […]
The Editor’s Picks for 2018 have been released for the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. According to the editorial team, the focus of this journal is on “the regulation of whole organismal function that requires the interplay of multiple organ and tissue systems.” The top comparative physiology articles of 2018 included: An article by Hersh et al., who provided evidence that little skates may be useful […]
Muscle wasting is a major complication associated with cirrhosis and liver failure. Normally the liver functions to convert ammonia into urea. But with liver failure, this process does not work well leading to high levels of circulating ammonia, which is thought to contribute to muscle wasting in mammals. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, explored whether birds have the same muscle wasting […]
Cold-tolerant insects have developed several strategies for dealing with cold temperatures. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology explored how spotted wing drosophila (Drosophila suzukii), in particular, adapted physiologically to cold exposure. They discovered that animals adapted to living in the cold had altered the structure of their cellular membranes in ways that kept the membrane fluid and prevented it from becoming rigid. Moreover, […]
Nile tilapia, Oreochromis niloticus, is a species of freshwater fish native to Egypt and Africa. Global warming has the potential to significantly impact this species as water temperatures above 32 to 36.5 degrees Celsius can induce young fish (10-30 days after fertilization) that are genotypically female to become masculinized. Moreover, a recent study published in PLOS ONE showed that some young fish choose to visit warmer waters. A new study published […]
In many mammals exposure to hypoxic conditions results in the release of a vasodilator called nitric oxide, which improves blood flow and protects oxygen delivery to tissues throughout the body. Diving animals appear to be unique in that some of their blood vessels stay constricted while they are diving even though they experience hypoxia. A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology explored […]
Life Lines by Dr. Dolittle 