mouse-biology

anonymous asked:

Why are larger animals so slow moving? Elephants, whales, even giants in shows like Game of Thrones. They all have slow, exaggerated movements. Would it be possible for a mythical creature to be extremely large but also quick (compared to humans)?

Metabolism is linked to body surface area to volume ratio. Smaller animals have a larger surface area to volume ratio. They lose heat quicker, they require more calories per kg of body weight, and their growth and reproductive cycles are faster.

Also, it takes physically more time to move a larger body. If a creature has a single step that moves 1 meter, it will take longer to move that limb than if the creature’s step is only 1cm.

By the same token, if you consider a heart beat, it takes longer for a heart to pump a large volume of blood from one chamber to the next than if it was a tiny heart.

It’d defy what we currently know about biology to have a massive creature that still had the speed and metabolism of, say, a hummingbird or a mouse.

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Hayley Whalvin captured this small, peaceful moment in Wimborne, England, of a “harvest mouse [who] sat in a dandelion having lunch.” Whalvin spent “an hour and a half with them, watching them play, sleep, and eat.” She tells us that when she viewed the frame on her screen, “I knew I had my shot.”

A giant neuron found wrapped around entire mouse brain

Like ivy plants that send runners out searching for something to cling to, the brain’s neurons send out shoots that connect with other neurons throughout the organ. A new digital reconstruction method shows three neurons that branch extensively throughout the brain, including one that wraps around its entire outer layer. The finding may help to explain how the brain creates consciousness.

Christof Koch, president of the Allen Institute for Brain Science in Seattle, Washington, explained his group’s new technique at a 15 February meeting of the Brain Research through Advancing Innovative Neurotechnologies initiative in Bethesda, Maryland. He showed how the team traced three neurons from a small, thin sheet of cells called the claustrum — an area that Koch believes acts as the seat of consciousness in mice and humans.

Crick, F. C. & Koch, C. Phil. Trans. R. Soc. Lond. B Biol. Sci. 360, 1271–1279 (2005).

Torgerson, C. M. et al. Hum. Brain Mapp. 36, 827–838 (2015).

A digital reconstruction of a neuron that encircles the mouse brain. Allen Institute for Brain Science

Expression of combinations of three different fluorescent proteins in a mouse brain produced ten different colored neurons. Individual neurons in a mouse brain appear in different colors in a fluorescence microscope. This “Brainbow” method enables many distinct cells within a brain circuit to be viewed at one time. 

Cambridge scientists create first self-developing embryo from stem cells

The transformation of a fertilised egg into a tiny living embryo ranks among nature’s most impressive feats. Now scientists have replicated this critical step towards a new life for the first time, growing an artificial mouse embryo from stem cells in the lab.

The cells, grown outside the body in a blob of gel, were shown to morph into primitive embryos that perfectly replicated the internal structures that emerge during normal development in the womb.

The scientists let the artificial embryos develop in culture for seven days – about one third of the way through the mouse pregnancy. By this point the cells had organised into two anatomical sections that would normally go on to form the placenta and the embryonic mouse.

The mouse embryo breakthrough is not designed to grow mice or babies outside the womb, but to open a new window on the embryo’s development just prior to implantation. Photograph: Redmond Durrell / Alamy/Alamy

A group called The Turning Point Project took out this full-page ad in the New York Times in 1999 after the publication of a paper including the image of Joseph Vacanti’s “earmouse.” The ad falsely claims that the mouse is a result of genetic engineering and includes the following criticisms of biotechnology:

“Does anyone think that it’s shocking, therefore, that this infant biotechnology industry feels it’s okay to capture the evolutionary process and to reshape the life on earth to suit its balance sheets?”

“Biotech companies are blithely removing components of human beings (and other creatures) and treating us all like auto parts at a swap meet.”

“Someday when one of these companies finally decides the public mood is receptive, will they make a human-gorilla combo to take care of heavy labor?”

“Have we lost our sanity?” 

So far, there exist no half-human, half-animal “chimeras” (like mermaids or centaurs) but we may soon have them”

Sometimes scientists are so focused on results that they forget about ethics, and it’s great that public groups are out there to focus on holding the labs accountable.

But, as you can see, in a lot of cases the accusers come off as rather phobic of change and science-illiterate. 

Macrophages in a mouse liver

Found in practically all tissues, macrophages (in blue) are the hungry cells of the immune system. They gobble up dying cells and harmful pathogens like bacteria to ensure tissues are happy and healthy. When a tissue is damaged, young macrophages are recruited by the bucket-load to the site of injury where they mature to speed up wound repair and eat trespassing bacteria. Some bacteria, like the one responsible for tuberculosis, can survive even after being eaten, eventually killing the macrophage and accelerating its spread within the tissue.

Image by Hendrik Herrmann.

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Incredible detailed video of a mouse brain  

Published on Jul 31, 2015

To make such a detailed model, researchers took specks of brain tissue and cut them into slices thousands of times thinner than a human hair.