Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

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Mice have special ‘jumping genes’ that help them survive viral infections

Researchers at the University of New South Wales (UNSW), Sydney discovered a ‘jumping gene’ that prevents the immune system of mice from overreacting to a viral infection. Jumping genes are movable nucleic acids, or transposable elements, that make up nearly 2/3 of the genome in mammals. They help regulate the expression of genes. Some transposable elements in the genome are new and some originated in ancient times. In the new […]

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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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Making heat to lose weight

There are many ways to stay warm on a cold day. We can seek shelter, turn up the thermostat, and huddle close together. Obvious physical adaptations to cold include fur, feathers, and clothing in the case of humans…and some pampered dogs. Blood vessels near the skin may also constrict to prevent heat loss and some animals develop a layer fat under the skin that acts like insulation. We may also […]

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Life at the top

Moving to high altitude requires a bit of an adjustment. One of the ways our bodies adjust to the low levels of oxygen is by making more red blood cells, which are responsible for transporting oxygen in the body. More red blood cells means that our blood can pick up more oxygen. If this process continues unchecked, however, it can lead to chronic mountain sickness, also known as Monge’s Disease. […]

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Early indicator of pregnancy complications

Mitochondria are organelles inside our cells that are essential for generating metabolic energy in the form of ATP. It is thought that these organelles originally came from aerobic bacteria that were ingested by the first eukaryotic cells. In fact, mitochondria have their very own DNA. Cells that have higher energy needs, like those in the brain and heart, contain more mitochondria.      When cells die, mitochondrial DNA can end up […]

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What happens in a forest doesn’t always stay in the forest…

So, a male scarlet tanager flies into a forest where he meets an irresistible rose-breasted grosbeak. They share some tasty insects, and the rest is history. Or is it? What happens in a forest, doesn’t always stay in a forest. In fact, this encounter resulted in a hybrid: This male bird, found in Pennsylvania, is the hybrid offspring of a male scarlet tanager (Piranga olivacea) and a female rose-breasted grosbeak […]

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New study discovers how zebrafish mend a broken heart

A new study has helped unravel the mystery explaining how zebrafish regenerate a broken heart. Their findings, published in Nature Genetics, reveal how these amazing little fish can regrow up to 20% of their heart in only 2 months following an injury. This regeneration is driven by signals released from special cells called fibroblasts. When the heart of zebrafish is injured by a stimulus that mimics a heart attack (using […]

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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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Heat may activate muscle growth and prevent atrophy

Skeletal muscle is not only important for our ability to move, it also plays a major role in metabolism. Under normal conditions, the routine processes of muscle growth (hypertrophy) and breakdown (atrophy) are in balance. While many of us are aware that exercise and healthy diets promote muscle growth, diseases and sedentary lifestyles can promote muscle atrophy. Studies examining the effects of heat on muscle – from environmental heat, direct […]

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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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