from the world's big
Just what every arachnophobe needed to hear.
- A new study suggests some spiders might lace their webs with neurotoxins similar to the ones in their venom.
- The toxins were shown to be effective at paralyzing insects injected with them.
- Previous studies showed that other spiders lace their webs with chemicals that repel large insects.
Just what we needed to know before walking into another spider web<div class="rm-shortcode" data-media_id="vV8EYzwn" data-player_id="FvQKszTI" data-rm-shortcode-id="37004fd34a066f4eee06fa5feba6c111"> <div id="botr_vV8EYzwn_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/vV8EYzwn-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/vV8EYzwn-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/vV8EYzwn-FvQKszTI.js"></script> </div> <p>The study, published in the <a href="https://doi.org/10.1021/acs.jproteome.0c00086" target="_blank">Journal of Proteome Research</a>, was carried out by Biochemical Ecologist Mario Palma of the University of São Paulo State, their Ph.D. student, Franciele Esteves, and their colleagues. They focused on the webs of the striking <a href="https://en.wikipedia.org/wiki/Trichonephila_clavipes" target="_blank">T. clavipes</a><em>,</em> also known as the Banana Spider.</p><p>These spiders are orb weavers, known for their complex and often large webs. They can have up to seven glands that produce silk for various <a href="https://www.loc.gov/everyday-mysteries/item/how-do-spiders-avoid-getting-tangled-in-their-own-webs/" target="_blank">purposes</a>, including catching prey, shielding themselves, protecting their eggs, mating rituals, and making webbing to walk on.<em></em></p><p>The researchers examined the spiders' various web producing glands. This revealed a spectrum of neurotoxin-like proteins not dissimilar to those found in the spider's venom present on the silk. On the web, these proteins are suspended in oily, fatty acids. <br> <br> Following up on this discovery, they tested the proteins' effectiveness on insects. Most of those test subjects were paralyzed less than a minute after exposure, and a few died. These experiences relied on the injection of the proteins rather than on absorption but did demonstrate their capacity. Further tests showed that the fatty acids the proteins reside in could allow them to enter the body of prey <a href="https://www.sciencealert.com/spider-webs-me-be-more-than-just-a-trap-they-might-also-do-the-butchering" target="_blank">insects</a>. </p><p>Previous studies demonstrated that some spiders can add certain chemicals to their webs to repel larger insects which could cause the spider trouble. So, the idea that some spiders are adding another chemical to the mix, this time to cause paralysis, isn't too far-fetched. </p><p>However, some scientists aren't so sure about all <a href="https://www.sciencenews.org/article/spiders-poisonous-webs-neuro-toxins-genes" target="_blank">this</a>. They call for further study into the mechanism of action to demonstrate that these proteins cause paralysis and rule out potential other applications.</p><p>So, those of you who like animal facts can take pride in knowing that spider webs sometimes have poison in them to stun their prey. Those of you who are terrified of spiders can fear the same information. Either way, walking into a spider web just got even less pleasant. </p>
The meteorites suggest astronomers may have small, early planets wrong.
- A group of meteorites that have come down all over the Earth have something in common.
- They all come from one early-universe baby planet, or planetesimal.
- That planetesimal was apparently not what astronomers expected.
Astronomers believe that before planets formed, there were lots of mini-planets, or planetesimals, many of which eventually broke apart — they're believed to be the source of meteorites that strike Earth. According to a recent study, a group of meteorites all around the globe may have come from the very same planetesimal. Not only is that a bit weird, but the evidence suggests that this former baby planet was not what scientists thought a planetesimal could be.
The research, "Meteorite evidence for partial differentiation and protracted accretion of planetesimals," was partially funded by NASA and is published in Science Advances.
Image source: Maria Starovoytova/Shutterstock
It's believed that planetesimals are formed out of the swirling mass of gas and dust that was our universe roughly 4.5 billion years ago. As the universe cooled, bits began to crash into each other, forming these small bodies in less than a few million years.
Early planetesimals, forming in the first 1.5 billion years of our solar system, would have pulled in radiogenic materials from the hot universe. This material gave off heat as it decayed, and so the cosmic rubble comprising these planetesimals was melted into a relatively homogeneous chondritic (melted) mass. Radiogenic materials would be less available to planetesimals formed later, and their rubble, though merged into a planetesimal, would be unmelted, or achondritic.
There may have been planetesimals that formed in the middle period. The study notes, "This could have resulted in partially differentiated internal structures, with individual bodies containing iron cores, achondritic silicate mantles, and chondritic crusts." However, there's been little evidence of such "intermediate" planetesimals.
Until now, it's been basically a binary proposition: melted or unmelted. Which gets us to the family of meteorites.
Image source: Carl Agee, Institute of Meteoritics, University of New Mexico/MIT News
When meteorites are found and studied, the type of planetesimal from which they came is usually clear: melted or unmelted. Not so for a family of meteorites called the "IIE irons." (IIE is their chemical type.)
As study co-author Benjamin Weiss of MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS) explains, "These IIE irons are oddball meteorites. They show both evidence of being from primordial objects that never melted, and also evidence for coming from a body that's completely or at least substantially melted. We haven't known where to put them, and that's what made us zero in on them."
Researchers had previously established that all of these IIE iron outliers — which themselves can be either achondritic or chondritic — came from the same planetesimal, and that raises some intriguing questions.
As study lead author Clara Maurel, a grad student at EAPS, puts it, "This is one example of a planetesimal that must have had melted and unmelted layers." Did that baby planet perhaps have a solid crust over a liquid mantle? "[The IIE irons encourage] searches for more evidence of composite planetary structures," she says. "Understanding the full spectrum of structures, from nonmelted to fully melted, is key to deciphering how planetesimals formed in the early solar system."
Back to the planetesimal
Image source: Maurel, et al
"Did this object melt enough that material sank to the center and formed a metallic core like that of the Earth? That was the missing piece to the story of these meteorites," said Maurel.
If that was the case, the scientists reasoned, might not such a core generate a magnetic field in the same way that Earth's core does? Some minerals in the planetesimal might have become oriented in the direction of the field, similarly to the way a compass works. And if all that's the case, those same minerals in the IIE irons might still retain that orientation.
The researchers acquired two of the IIE iron meteorites, named Colomera and Techado, in which they detected iron-nickel minerals known for their ability to retain magnetic properties.
The team took their meteorites to the Lawrence Berkeley National Laboratory for analysis using the lab's Advanced Light Source, which can detect minerals' magnetic direction using X-rays that interact with their grains.
The electrons in both IIE irons were pointed in the same direction, providing additional confirmation of their common source and suggesting their planetesimal indeed had a magnetic field roughly equivalent in size to the Earth's.
The simplest explanation for the effect was that the planetesimal had a liquid metallic core that would have been "several tens of kilometers wide." This implication suggests that previous assumptions regarding the speedy formation of planetesimals is wrong. This planetesimal must have formed over the course of several million years.
Back to the IIE irons
Cooling profiles of a partially differentiated IIE parent body.
Image source: Maurel, et al
All of this got the researchers wondering where in this surprisingly complex planetesimal the meteorites might have come from. They partnered with scientists from the University of Chicago to develop models of how this all might have gone down.
Maurel's team came to suspect that after the planetesimal cooled down and imprinted the magnetic field on the minerals, collisions with other bodies tore them away. She hypothesizes, "As the body cools, the meteorites in these pockets will imprint this magnetic field in their minerals. At some point, the magnetic field will decay, but the imprint will remain. Later on, this body is going to undergo a lot of other collisions until the ultimate collisions that will place these meteorites on Earth's trajectory."
It is unknown whether the planetesimal that produced the IIR irons was unusual, or if its history is typical for planetesimals. If so, the simple melted/unmelted dichotomy needs to be reconsidered.
"Most bodies in the asteroid belt appear unmelted on their surface. If we're eventually able to see inside asteroids," says Weiss, "we might test this idea. Maybe some asteroids are melted inside, and bodies like this planetesimal are actually common."
Researchers find an unusual property of a bacteria that can breathe in metal.
- Scientists discover Shewanella oneidensis bacterium can "breathe in" certain metals and compounds.
- The bacteria produces a material that can be used to transfer electrons.
- Applications of the finding range from medical devices to new generation of sensors.
No, its not just to keep you warm with hair you don't have.
- A new study suggests that goosebumps are part of a larger system that not only keeps us warm, but also helps hair to heal.
- The sympathetic nerve system reacts to cold air with goose skin. If it stays on long enough, it orders new hair growth.
- The authors note that other, currently unknown, connections between this system and other parts of the body are likely to exist.
A hair-raising study<p>In animals, many organs are made of three kinds of tissue: epithelium, mesenchyme, and nerve. In the skin, which is an organ, a nerve connects to muscle in the mesenchyme. This nerve is part of the sympathetic nervous system and helps maintain homeostasis. The muscle itself is connected to stem cells in the epithelium that heal wounds and regenerate hair follicles.</p><p>The researchers focused on mice, as is typical in these studies, but suggest that the findings are also applicable to humans given the similarity between our skin and hair cells. </p><p>The researchers examined the behavior and structure of the nerve under an electron microscope. To their surprise, the nerve was not only attached to the previously mentioned muscle tissue but also wrapped around hair follicle stem cells. </p><p>In normal conditions, the sympathetic nervous system is always operating at a low level. This keeps the body functioning normally. When the researchers observed this behavior, they noticed signals being sent by the nervous system to the stem cells in the hair follicles. These signals seem to keep the stem cells at the ready for potential use. </p><p>However, when the researchers exposed the tissues to the cold, the activity ramped up. A flood of neurotransmitters was released, and the stem cells activated. This prompted new hair growth to begin. </p><p>Another experiment dove into how the nerve reached the stem cells in the first place. Co-Author Yulia Shwartz explained the findings in a press release:</p><p>"We discovered that the signal comes from the developing hair follicle itself. It secretes a protein that regulates the formation of the smooth muscle, which then attracts the sympathetic nerve. Then in the adult, the interaction turns around, with the nerve and muscle together regulating the hair follicle stem cells to regenerate the new hair follicle. It's closing the whole circle -- the developing hair follicle is establishing its own niche." </p><p>Putting this together, it appears that goosebumps are part of a two-phased response to cold. In the first, the muscle below the skin is stimulated to form goosebumps. If this stimulation lasts long enough, the second phase kicks in, with the sympathetic nervous system calling for new hair growth and repairs for the old ones to be made in response to the cold. </p>
This is interesting and all, but what possible application could this information have?<div class="rm-shortcode" data-media_id="a1mxkAJg" data-player_id="FvQKszTI" data-rm-shortcode-id="34227067ef7afd2e24cf95e8c455de17"> <div id="botr_a1mxkAJg_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/a1mxkAJg-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/a1mxkAJg-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/a1mxkAJg-FvQKszTI.js"></script> </div> <p>In their <a href="https://www.eurekalert.org/pub_releases/2020-07/hu-trr072020.php" target="_blank">press release</a>, the authors suggest that further research can focus on how the body repairs itself in response to environmental stimuli in various situations. The findings also imply that other currently unsuspected connections between the sympathetic nervous system and other parts of the body exist. These potential interactions will undoubtedly be searched for and examined.</p><p> Everybody gets goosebumps now and then. We've always assumed we knew why we still get them, even though the hypothesis had some holes. This study's findings show that the benefits of getting goosebumps are more complex than initially thought. It just goes to remind us that we still have much to learn about even the most mundane things.</p>
A new study shows white dwarf stars create an essential component of life.
- White dwarf stars create carbon atoms in the Milky Way galaxy, shows new study.
- Carbon is an essential component of life.
- White dwarfs make carbon in their hot insides before the stars die.