Goldilocks’ first black hole; Metabolism of Toxoplasma gondii; pumping at muscle speed

This week: Physicists conducted a biological study, engineers built a waste recycling suit for astronauts (and worm riders), and astronomers identified the first intermediate-mass black hole, and it’s right here in our galactic backyard.

Water pumping

Observing that human muscle tissue is about 70% water, physicists at the University of Michigan created a theoretical model of the role of water in muscle contraction and report that the speed of a fluid through a muscle fiber determines the speed of muscle contraction. But they also found a strange kind of elasticity, which, in keeping with the “Snakes on a Plane” principle, they call odd elasticity. This allows the muscle to generate energy through three-dimensional deformations, as observed by the vertical swelling of the muscles when they contract lengthwise, often while posing in the mirror and referring to the price of admission to the gun show.

UM physicist Suraj Shankar says, “Our results suggest that even such basic questions as how fast muscles can contract or how many ways muscles can generate force have new and unexpected answers when one takes a more integrated view and more holistically of muscle as a complex and hierarchically organized material rather than just a bag of molecules is more than the sum of its parts.

Space walk without rhythm

Ideally, astronauts should enjoy spacewalks as observers of the unfolding grandeur of the universe without the undignified and diminishing requirement of wearing adult diapers. The unsanitary reality of life in space is that human biological demands supersede our evolution into floating, transdimensional star children and astronauts wear full diapers. Another disadvantage is that EVA urination bypasses the recycling system on the International Space Station and represents waste in a resource-poor environment.

Researchers at Cornell University, inspired by the waste-recycling suits worn by the Fremen in the movies “Dune Part One” and “Dune Two: The Squeakquel,” have developed an undergarment that could solve both problems for astronauts next. It includes a vacuum-based external catheter that directs urination to a combined forward-reverse osmosis unit and provides a continuous supply of drinking water. This is a simplified description of a much more technical part of the kit, which you can read about here.

Parasite Eve

Toxoplasma gondii is a parasite that causes an incurable condition that can change behavior called toxoplasmosis. It reproduces in felids and ultimately seeks to infect rodents to make them more amenable to approaching cats. There is no vaccine for toxoplasmosis, in part because the biological mechanisms of infection are poorly studied, so a team at the University of Wisconsin-Madison conducted an optical imaging study to better understand it. They used a noninvasive technology called optical metabolic imaging to monitor metabolic activity inside cells in real time.

They report that during the course of infection, host cells became more oxidized and the lifetime of NAD(P)H increased—this extra energy powers the parasite during reproduction. They also found a dynamic in the interaction of T gondii with the host cell surface, to which they applied the vaguely revolting name “kiss and spit.”

Scientist Gina Gallego-Lopez says: “A cell can become infected while the cells around it are not; it’s like the parasite ‘kisses’ those cells and then injects some proteins – kiss and spit,” she says. “To our surprise, we were able to see similar changes as full infection. So it seems like a simple ‘kiss’ from the parasite is enough to induce changes in the host cell.”

The new black hole has just fallen

Omega Centauri is a globular cluster located in the Milky Way galaxy, 17,090 light-years from the Sun and visible in the southern sky. A gravitationally bound cluster of 10 million stars, it is the most massive globular cluster in our galaxy. Scientists believe it is the surviving core of another galaxy that was captured by the Milky Way and stripped of its outer star populations. For years, astronomers have speculated that if it is, in fact, the core of a galaxy, Omega Centauri may contain a central black hole.

Now, researchers at the Max Planck Institute for Astronomy have confirmed this suspicion with a detailed study of stellar trajectories within the cluster. The researchers compiled a massive catalog of the motions of stars within Omega Centauri, calculating the velocities of 1.4 million stars from 500 Hubble images. They eventually focused attention on seven fast-moving stars in the central region, which exhibited speeds and motions that could only be explained by an invisible gravitational body.

Here’s the cool part: This black hole represents a missing link between stellar-mass black holes and supermassive black holes—an intermediate-mass black hole that has been predicted but never seen before. The reason it is so much smaller than the black holes normally found in the cores of galaxies is because Omega Centauri itself is frozen in time – with its stable population of core stars and no external population of stars, the black hole cannot to feed and increase its size.

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