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#FluorescenceFriday #cellbiology #immunology #Actin dynamics at the immunological synapse (IS) between a Jurkat T cell and an antigen-presenting coverslip, as seen by total internal reflection structured illumination microscopy (TIRF-SIM). John Hammer's group #NIH used our TIRF-SIM to show that formins rearrange inward flowing actin filaments from the outer lamellipodial...

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The most detailed 3D reconstruction of a cell ever created. Blows my mind every time. But what exactly are we looking at here? The average human cell contains: ~ 15-20 total distinct organelle types, totalling between ~1-10 million working together per cell. All these nano-machines in the cell are made up of proteins. ~ 8,000-10,000 distinct types of unique proteins, adding up to between 40 million - 10 trillion total proteins making up all those cellular systems. ~ 10,000 - 15,000 distinct types of RNA shuttling information around the cell, totalling up to ~10 million RNA molecules moving around the cell simultaneously. ~ Billions of Lipid molecules packed together into the cell membrane, which is also packed tightly with millions more protein-based nano-machines. And let's not forget billions of lines of DNA information to build and run it all. That's TRILLIONS of of individual molecular pieces working together to make a single cell function. That means there is more complexity in a single cell than humanity's largest cities. And people still believe this wasn't Divinely Designed. This is God's Glory on Display. But to make the point. A cell couldn't have evolved from some nebulous simpler "protocell" because even the simplest cells still require massive complexity. The "simplest" cell ever created was engineered by scientists knocking out pieces of a functional cell until it stopped functioning. Here is what they found is the absolute necessary minimal requirements of a cell to function: - Over ~531,000 lines of coded DNA information - 473 total genes to create hundreds of unique protein products (they later added 19 genes back in because the cell was so weak) - Hundreds of thousands of total proteins all working together - Extensive regulatory networks guiding all these interactions If the cell doesn't have all these systems in place, from the start... it doesn't live. Cell rely on an intricate network of complex systems, which are themselves built from complex interconnected pieces woven together into an incomprehensibly complex web of functionilty. Only intelligence has ever been observed creation vast interconnected systems like this. Life was clearly Created. It couldn't happen any other way.

Divinely Designed

166,099 Aufrufe • vor 2 Monaten

Some microbes carry a protein, called SNIPE, that "chops up" phage DNA as it's being injected into the cell. This is a new mechanism for phage defense! CRISPR–Cas and restriction enzymes also evolved to fight against phages, but they work by recognizing sequences. SNIPE works, instead, by sensing "touch." SNIPE is a protein with about 500 amino acids. After it's made by the ribosome, it latches onto ManYZ, two proteins which sit on the cell's inner membrane. (ManYZ is an importer; it brings mannose and other sugars into the cell.) Once attached to ManYZ, SNIPE sits and waits for an invading phage. Some phages, including lambda, actually infect cells by pushing their DNA through this ManYZ channel. Lambda uses its "tail" to reach inside the protein channel, basically, and inject its DNA. When this physical touch happens, though, SNIPE is waiting. As soon as the phage DNA starts entering the cell, and passes through ManYZ and SNIPE, it gets immediately destroyed. This means that SNIPE is the first phage defense system discovered, so far, that uses spatial positioning at the injection site to destroy invaders. But there are caveats, of course. If you untether SNIPE from ManYZ, such that it can freely diffuse through the cell, it will chew up the bacterium's genome. It is not a highly discerning nuclease! Also, SNIPE is not found in most bacteria. A prior pangenome study, which sequenced lots of different microbes, found that roughly a third of well-studied bacterial lineages had at least one member with a SNIPE-like protein. (For this paper, they just ported one of those homologs into an E. coli laboratory strain.) And finally, because SNIPE's mechanism is tightly tied to ManYZ, it cannot be used to defend against phages that enter the cell through different routes. T4 phages, for example, inject their DNA straight through the cell membrane and into the cytoplasm, without interacting with ManYZ. This is a nice basic science paper. Applications TBD. (Just remember that scientists figured out that bacteria had a phage defense system, called CRISPR-Cas, many years before it was repurposed into a gene-editing tool.) P.S. The video below shows how cells with the SNIPE gene (middle row) kill invading phages, and thus continue growing and dividing. Empty vector (top row) refers to bacteria carrying a plasmid with no SNIPE gene; this is a control group. And SNIPE E414A refers to cells which received a mutated SNIPE gene, where the glutamate at position 414 has been changed to an alanine, thus destroying the protein's nuclease activity. These cells also die when they get infected with a phage.

Niko McCarty.

20,527 Aufrufe • vor 5 Monaten

Madain Saleh, also known as Al-Hijr, is a pre-Islamic archaeological site located in the northwest of Saudi Arabia. It is one of the most important archaeological sites in the Middle East and was designated as a UNESCO World Heritage site in 2008. Madain Saleh is a place of great historical and cultural significance, and it is a must-visit destination for anyone interested in the history and culture of the Arabian Peninsula. Madain Saleh was the second city of the Nabataean kingdom, which was established in 2nd Century BC. The Nabataeans were an Arab tribe who were known for their expertise in carving tombs and buildings out of rock. They were also skilled in agriculture, trade, and commerce. The Nabataean kingdom was centered in Petra, which is located in modern-day Jordan. Madain Saleh served as a strategic outpost for Nabataeans, and it was an important stop on the trade routes that connected the Arabian Peninsula with the Mediterranean world. Archaeological site of Madain Saleh covers an area of 13 square kilometers. It is located in a remote desert region, and it is surrounded by rocky mountains and valleys. The site contains around 130 tombs, which were carved out of the sandstone cliffs. The tombs are adorned with intricate carvings and inscriptions, which provide insights into the culture and religion of the Nabataeans. The most famous tomb at Madain Saleh is the Qasr Al-Farid, which means "the lonely castle." This tomb is located on a hilltop and is surrounded by a large courtyard. It is the largest tomb at the site, and it is considered to be one of the finest examples of Nabataean architecture. The tomb was never completed, and it is believed that it was abandoned after the death of the Nabataean king who commissioned it. Another important tomb at Madain Saleh is the Tomb of Lihyan son of Kuza. This tomb is located in the southern part of the site and is carved into a rock cliff. It features a large entrance hall, a central chamber, and a series of smaller rooms. The tomb is decorated with intricate carvings and inscriptions, which provide insights into the religious beliefs of Nabataeans. Madain Saleh is not just a site of tombs; it also contains a number of other important structures. These include the Al-Khuraymat and Al-Sabika temples, which were used for religious ceremonies and rituals. The site also contains a number of houses, wells, and cisterns, which provide insights into the daily lives of the Nabataeans. Madain Saleh was abandoned in the 3rd Century AD, after decline of the Nabataean kingdom. The site was rediscovered in the 19th Century by the Swiss traveler Johann Ludwig Burckhardt. Since then, it has been studied by archaeologists from all over the world. The site is now managed by the Saudi Commission for Tourism and National Heritage, which has carried out extensive restoration and preservation work. Madain Saleh is not just a site of historical and cultural significance; it is also a place of great natural beauty. The site is surrounded by rugged mountains and valleys, and it is home to a diverse range of flora and fauna. Visitors to the site can enjoy hiking and camping, as well as exploring the ancient ruins. Madain Saleh is a site of great historical and cultural significance, and it is a must-visit destination for anyone interested in the history and culture of the Arabian Peninsula. Ancient ruins at Madain Saleh provide a glimpse into the engineering and architectural skills of the Nabataeans, as well as their religious beliefs and cultural practices. However, as the site becomes an increasingly popular tourist destination, there are concerns about its preservation and the impact of tourism on the local environment. It is important that the Saudi government and local communities work together to ensure that the site is protected and that tourism is managed in a sustainable way. 🎥© Paris Verra #archaeohistories

Archaeo - Histories

196,549 Aufrufe • vor 2 Jahren

Contrail lesson! 1. “Chemtrails” don’t exist. Just to get that out of the way. 2. Observe the satellite loop and Skew-T chart. In the IR satellite loop you can see yesterday, the West Coast had a decent short wave ridge suppressing moisture over California and Nevada. Today, you can see moisture from a low pressure over the Pacific spilling over the ridge that is now moving east of California. This is upper level moisture ADVECTING into the area. This upper level moisture is mainly above the 500mb level, or 20,000ft. 3. Now observe the Skew-T chart. Particularly clue into the 300mb level. This is a perfect example of what I talk about all the time, and why it’s important to pay attention to the 300mb level. This moisture layer is advecting particularly at the 300mb level, and synoptic scale cirrus development, and advection, typically occurs at 300mb. This is key because aircraft are flying at and above the 300mb level. 4. So, lastly, observe the pictures that I took of the sky over northern Nevada at the time of this post. You can see the layer of cirrus as well as contrails persisting in that moisture layer, exactly as depicted in the satellite shot AND confirmed by the Skew-T chart. Keep in mind that temperatures at this level of the atmosphere are typically -20 to -50°C. In this case, you can see that the temperature at 300mb is -40°C and relative humidities at this level are far different than what you experience at the surface. Any decrease in the gap between temperature and dewpoint at this level can significantly increase the relative humidity. This is why it’s referred to as “relative”because it’s far different than temperatures and dew points at the surface. So, to bring it all together, aircraft flying at these altitudes, which most commercial and military aircraft do, injecting warm, moist air from the engines rapidly into the super cooled environment, not only instantly form contrails, but when relative humidities are as depicted in this example, will enable contrails to persist for hours at a time supported by the moisture existing in that layer. This is what causes persistent contrails. These ARE NOT “chemtrails” and because they persist, does not, and will not ever, make them “chemtrails.” Now that you all needed your government to tell you that climate change was a hoax and I’ve been telling you for years that the “Geoengineering” and “chemtrail” nonsense are propaganda directly related to the climate change hoax, hopefully you can take some time to learn the basics of the atmosphere and understand what I’m showing you here, and how it works, so you’re not fooled by climate propaganda going forward. Thank you for your attention to this matter. 💪🏼🇺🇸

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🚨 SCIENTISTS JUST FOUND AN ANCIENT OCEAN FLOOR WRAPPED AROUND EARTH’S CORE. Using seismic waves recorded by stations buried in Antarctic ice, researchers have created the highest-resolution map yet of the boundary between Earth’s mantle and outer core nearly 3,000 km beneath our feet. They discovered thin but widespread patches of dense material that dramatically slow down seismic waves. The most likely explanation: these are fragments of ancient oceanic crust that sank into the deep mantle long ago and have been moved around by convection currents for hundreds of millions of years. In some places, these structures rise up to five times higher than Mount Everest. Why this matters: • It reveals that Earth’s deep interior is far more complex and dynamic than we thought • These patches likely influence how heat flows from the core into the mantle, which affects mantle convection and volcanic activity • They may also play a role in the behavior of Earth’s magnetic field, which is generated in the outer core • Understanding this boundary helps us better model how our planet has evolved over billions of years The deeper implication: We usually think of the deep Earth as relatively simple layers. This research shows that the core-mantle boundary is more like a rugged, geologically active landscape with ancient “mountains” made of recycled ocean floor. It’s a powerful reminder that Earth is a single, interconnected system what happens at the surface (like plate tectonics) can eventually end up reshaping the deepest parts of our planet, and vice versa. We’re still only beginning to map the true complexity hidden beneath our feet. How do you think discovering ancient ocean crust at the core-mantle boundary changes the way we should think about Earth’s internal dynamics? Follow for more frontier Earth science and discoveries about our planet’s hidden interior.

TheNewPhysics

37,534 Aufrufe • vor 1 Monat

A single E. coli cell, placed on a dish, will become 70 billion cells in just 12 hours. That’s exponential growth. But a new preprint shows that it's possible to engineer E. coli to grow linearly instead, where only one daughter cell continues dividing and the other stops. First, some context. In nature, there is a bacterium called Mycobacterium smegmatis (initially discovered in 1884 in ulcers scraped from syphilis patients.) M. smegmatis is weird because it divides asymmetrically. These cells grow only from one end, and all their cell wall biosynthesis machinery is located on that one end. So when the cell divides, one daughter gets this machinery and the other gets nothing. The daughter that gets the machinery can keep dividing immediately, but the other daughter has to remake all that machinery from scratch, so its growth is delayed. E. coli doesn’t grow like this. When it divides, it pinches in the middle and splits everything evenly. Enzymes, metabolites, and proteins get partitioned more or less randomly between the two daughters. For the new preprint, though, researchers engineered E. coli to behave more like M. smegmatis. Here is how they did it: First, they deleted a gene called cyaA, which encodes an enzyme (adenylate cyclase) that makes a molecule called cAMP. cAMP is SUPER IMPORTANT! It is a nutrient sensor that instructs E. coli to switch on genes that help it digest non-glucose carbon sources when glucose is scarce. Without cAMP, E. coli cells growing on alternative carbon sources will starve; they won’t know how to eat the food. Next, they added back a “split” version of the cyaA gene into the cells. In other words, they split the gene in two so that each half of the enzyme is made separately. Cells can only make cAMP, and thus eat non-glucose carbon sources, if these two halves come together. To facilitate that “coming together,” the researchers also fused the split cyaA proteins to sticky proteins that clump together, and to a fluorescent protein (to make it easy to track these molecules in the cell.) So now some interesting things start to happen if you grow E. coli on a growth medium lacking glucose. As the cell grows, its cyaA “halves” start clumping together into a giant ball. Inside the aggregate, the two enzyme halves come together and make cAMP. And when the cell gets big enough and divides, the clump of cyaA RANDOMLY goes to either daughter cell #1 or #2. The daughter that gets the aggregate (called PA+ in this paper) can keep dividing. The daughter that doesn’t (PA–) cannot. It still grows a few times — about four divisions — because it inherits some leftover cAMP from its mother. But after that, the metabolite is diluted away, and the cell stops growing. PA+ cells went through about 23 divisions on average before their aggregate decayed. And the population of cells, as a whole, grew linearly. This paper is cool because there are many applications where exponential growth is too unpredictable and, perhaps, unsafe. If you want to engineer bacteria to deliver drugs, clean up waste, or live in the gut, you don’t want them to double uncontrollably. This paper shows you can make them expand in a controlled, linear way. Alas, mutations could break this whole engineered system. A mutation that restores cyaA, for example, would give cells a new way to make cAMP. Mutations that make the aggregates split between daughters would break the asymmetry, too. But still, I really enjoy proof-of-concept engineering papers like this.

Niko McCarty.

58,047 Aufrufe • vor 11 Monaten

🚨BREAKING: Another ICE agent has been caught on video illegally pointing a firearm at a U.S. citizen, in Lemonwood, California. In the video, an unmarked ICE vehicle is stopped in the middle of the road… no vehicles are in front of it, and nothing is preventing them from driving forward. Instead of continuing to drive down the road, the ICE agent is blocking a pickup truck from turning, while pointing a gun, out their window, directly at the driver of that truck. The truck backs up, but the agent still keeps the firearm pointed at the driver. Only AFTER people begin honking their horns does the agent lower their weapon, and drive away. The law states that pointing a firearm at someone is considered a serious threat of deadly force. It is only justified when an officer has an objectively reasonable belief that they are facing an immediate threat of death, or serious bodily harm. It is not legally allowed to be used to control traffic, and it is not legally allowed to be used as intimidation. And that’s exactly why this video should be alarming to you. The agent is not boxed in… nothing is preventing them from driving down the street. Meanwhile, the agent is the one preventing the truck from continuing its turn. And they are doing so while pointing a gun at the driver. So, the question becomes… What immediate threat justified the ICE agent to stop their car, and point a firearm at a U.S. citizen? Because we are seeing a growing pattern, of publicly documented incidents, where ICE agents point firearms at legal observers, journalists, and bystanders during enforcement encounters… when they are not facing an immediate threat of death. That is not how public safety works. Pointing a firearm at someone is one of the most serious things an officer can do, because it instantly escalates an encounter into a potential deadly force situation. And that is exactly why the law is supposed to restrict it. Every unnecessary drawn gun increases the risk of a wrong judgment, and a fatal mistake. And when there is no accountability, for when that line gets crossed, drawing a gun because the normal for every situation. And when it becomes normal, more people’s lives are put in danger.

Jesus Freakin Congress

231,527 Aufrufe • vor 1 Monat