Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Agriculture, Aquaculture, and Livestock

Goldfish learn how to drive and target similar visual cues as humans

Researchers at Ben-Gurion University of the Negev constructed a tank on wheels that goldfish actually learned how to “drive”. Using cameras, the “car” was able to move in the direction the fish swam. They then tested whether the fish could purposefully navigate the car towards a target and observed that the fish could indeed swim towards a target in return for a treat, of course. In a prior study, the […]

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Aging and Immortality

Have you ever heard of the ‘immortal’ jellyfish, Turritopsis dohrnii? These tiny creatures (about 4.5 mm) are aptly named for their ability to essentially live forever. According to the Natural History Museum, when these jellyfish are damaged, they can actually revert to a prior life cycle as a polyp and become an adult jellyfish (aka, medusa) all over again. This process is called transdifferentiation. Check out this video from the […]

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Causes and consequences of stiff arteries

In a new review article published in Physiology, researchers speculate that arterial stiffness in middle-aged adults may actually be the body’s way of trying to compensate for widening of the blood vessel walls as we age. But that benefit turns into a risk with aging as it increases the flow of blood into organs like the brain, kidney, and heart and damages the small blood vessels in those organs. Interestingly, […]

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Chronic stress during pregnancy increases risk of stillbirth and preterm delivery

At the end of pregnancy, levels of the hormone oxytocin increase to stimulate parturition, or childbirth. The stress hormone cortisol is also important for normal fetal development and, like oxytocin, cortisol increases at the end of pregnancy. This may help explain why chronic stress during pregnancy increases the risk of complications such as stillbirth.   A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative […]

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Domestic zebrafish are less plastic

Zebrafish have been used in medical research since at least the 1970’s as their anatomy, physiology, as well as genetics are similar to humans. Other advantages to studying zebrafish is that they are inexpensive to raise, and they reproduce well in captivity. The ability to adjust one’s physiology in response to varying environments is called plasticity. An organism may encounter any number of environmental fluctuations (light/dark, temperatures, predation risk, noise, […]

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Are declines in food availability to blame for the menu change?

Yesterday, we marveled over the recent sightings of two killer whales targeting sharks off the coast of South Africa. The recent uptick in shark hunting has scientists wondering how the loss of great white sharks will impact the ecosystem. But it also has some wondering why the orcas are targeting so many sharks when their diets typically consist of a variety of fish and marine mammals.   Clues may lie […]

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Killer whales scare off sharks

A pair of killer whales, nicknamed ‘Port and Starboard’, has been terrorizing great white sharks. In recent years as many as 8 sharks (possibly more) have succumbed to the pair. Many of the discovered sharks were missing their fatty liver and sometimes their heart. While orca hunting escapades are not particularly newsworthy, the antics of these orcas have attracted the attention of scientists as they are altering the ecosystem. Once […]

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Nitrites and noses

If you have ever had a fish tank, you may be familiar with monitoring ammonia levels in the water. Ammonia levels can rise due to overcrowding, overfeeding, as well as fish waste. Nitrite levels in the water also require monitoring as nitrite can bind to hemoglobin, which prevents oxygen from binding. In effect, by preventing oxygen from binding, the fish can succumb to hypoxia. Hannah Hughes, a graduate student working […]

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More than milk

Prolactin is an important pituitary hormone in mammals that works with oxytocin to provide milk for offspring. It also plays a role in promoting bonding between new mothers and their offspring. But did you know that non-mammalian vertebrates have prolactin too? Considering non-mammalian organisms do not have mammary glands, it must serve a different purpose in these animals.   As it turns out, prolactin is very important in the ability […]

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Geriatric bees

Jacob Pithan, a graduate student in the laboratory of Dr. Kendra Greenlee (North Dakota State University), presented their research examining how aging affects exercise performance as well as oxidative health at last month’s Experimental Biology conference in Philadelphia. The oxidative stress theory of aging postulates that aging results from an overproduction of free radicals along with a decrease in antioxidants that can scavenge them. The problem with free radicals is […]

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