Tag Archives: cells

Million-year-old dormant microbes beneath ocean floor push life to its absolute limits

Every living creature requires energy in order to subsist, multiply, and pass on its genes. How much energy an animal requires depends on their habitat and size, among many other things. But some cells require so little energy, it just boggles the mind.

Recently, researchers have identified microbial cells that live in sediments kilometers beneath the ocean floor that require a tiny fraction of a calorie to survive. In fact, many of these cells may be up to 100 million years old, something that is owed to their suspended animation state.

Speaking to Quanta Magazine, James Bradly, a geobiologist at Queen Mary University of London and the lead author of a new study that modeled the suboceanic biosphere, said that “This entire biosphere of cells, equivalent in size to the world’s soils, hardly has enough energy to survive.”

Bradly, along with colleagues from universities across the world, employed existing data from previous drilling operations and lab experiments, which they modeled to extrapolate a detailed profile of sub-seafloor sediments.

Researchers projected values like the age of the sediments, the density of cells living inside them, which nutrients are available to these cells, and the rate at which the cells metabolize the nutrients. The findings were quite staggering.

When the researchers calculated the power consumption of the dormant cells living inside the sediments, they found that they were close to the absolute theoretical limit for energy requirements to sustain life.

These sub-seafloor microbes use only 0.1% of the power consumed by creatures living in the upper 200 meters of the ocean. The buried microbes survive at power levels orders of magnitude lower than any organism ever measured in a laboratory, the authors reported in the journal Science Advances.

Previously, in 2015, Douglas LaRowe and Jan Amend, both at the University of Southern California in Los Angeles, estimated the lowest amount of power required to sustain life. Even life that is dormant for millions of years in a zombified state waiting for the right conditions for reanimation needs at least some energy for fundamental biological processes like the repair of DNA damage.

Power per cell (watts) calculated on a global scale and depth-integrated for the (A) oxic, (B) sulfate-reducing, and (C) methanogenic sedimentary layers. White areas denote absence of the corresponding catabolic zone. Credit: Science Advances.

Even if an individual cell doesn’t divide, it would still need at least a zeptowatt, or 10−21 watts, in order to survive. The sub-seafloor microbes are just slightly above this threshold.

Some of these microbes may be up to 100 million years old, researchers report. Given their phenomenally low energy requirements, this all might change how biologists see cellular evolution.

The findings also open the possibility that life may exist in places that scientists had previously discarded as impossible habitats — and this includes other planets, as well.

The sediment samples that were used for the new theoretical model are around 2.6 million years old. However, deeper sediments might house even more starving cells, pushing energy requirements further to the brink.

Internal cell structures revealed by powerful 3D microscopy technique

A new imaging technique called cryo-SR/EM can capture cells in unprecedented, 3D detail.

Image credits D. Hoffman et al., (2020), Science.

The insides of living cells are very cramped, busy, but fascinating places. Sadly, because they’re so small, we’ve never been able to take a proper look at what’s going on inside there.

However, a new technique that combines both optical and electron microscopy may allow us to do just that, and in very high detail to boot.

Zoomed in

“This is a very powerful method,” says Harald Hess, a senior group leader at the Howard Hughes Medical Institute’s Janelia Research Campus, US.

Cryo-SR/EM combines data captured from electron microscopy with high-resolution optical microscope imaging to create detailed 3D models of the inside of cells.

Separately, these two approaches are powerful but limited. Optical (or light) microscopes can easily differentiate between individual cell structures when fluorescent molecules are attached to them — this is known as super-resolution (SR) fluorescence microscopy. While it does provide a clear picture, SR fluorescence microscopy isn’t able to show all the proteins swishing about inside a cell at the same time, making it hard to see how different bits interact with everything else.

On the other hand, electron microscopy (EM) can ‘see’ virtually everything that’s happening inside a cell in very high detail, but it can be too powerful for its own sake. The wealth of features inside a cell, all seen in very high detail, can make it difficult to understand what you’re looking at.

The team worked to combine these two techniques into a single one that enhances their strengths while balancing out their respective limitations.

Cryo-SR/EM involves first freezing a cell or group of cells under high pressure; this step instantly freezes their internal activity without allowing for ice crystals to form (these can easily rupture cellular structures). Next, the samples are placed into a cryogenic chamber where they’re imaged in 3D using SR fluorescence microscopy. Finally, the samples are removed, embedded in resin, and viewed under an electron microscope (this paper used a powerful device developed in Hess’ lab). This step involves shooting a beam of ions at the cell, producing images of successively layers of the cell. A computer program is used to piece these images back together into a 3D reconstruction.

For the final step, all the data is pooled together, creating a very high-detail 3D model of the cell’s interior.

Techniques such as cryo-SR/EM promise to let us peek into natural systems that were previously just too tiny to spot — and they let us do so in extreme detail. One particularly-exciting possibility is that cryo-SR/EM will allow researchers to observe snapshots of cellular processes as they unfold, propelling forward basic science and its applications in fields such as genetic engineering, bioengineering, biochemistry, and medicine.

The paper “Correlative three-dimensional super-resolution and block-face electron microscopy of whole vitreously frozen cells” has been published in the journal Science.

The world’s first ‘living machines’ can move, carry loads, and repair themselves

Researchers at the University of Vermont have repurposed living cells into entirely new life-forms — which they call “xenobots”.

The xenobot designs (top) and real-life counterparts (bottom).
Image credits Douglas Blackiston / Tufts University.

These “living machines” are built from frog embryo cells that have been repurposed, ‘welded’ together into body forms never seen in nature. The millimeter-wide xenobots are also fully-functional: they can move, perform tasks such as carrying objects and healing themselves after sustaining damage.

This is the first time anyone “designs completely biological machines from the ground up,” the team writes in their new study.

It’s alive!

“These are novel living machines,” says Joshua Bongard, a professor in UVM’s Department of Computer Science and Complex Systems Center and co-lead author of the study. “They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism.”

“It’s a step toward using computer-designed organisms for intelligent drug delivery.”

The xenobots were designed with the Deep Green supercomputer cluster at UVM using an evolutionary algorithm to create thousands of candidate body forms. The researchers, led by doctoral student Sam Kriegman, the paper’s lead author, would assign the computer certain tasks for the design — such as achieving locomotion in one direction — and the computer would reassemble a few hundred simulated cells into different body shapes to achieve that goal. The software had a basic set of rules regarding what the cells could and couldn’t do and tested each design against these parameters. After a hundred runs of the algorithm, the team selected the most promising of the successful designs and set about building them.

The design of the xenobots.
Image credits Sam Kriegman, Douglas Blackiston, Michael Levin, Josh Bongard, (2020), PNAS.

This task was handled by a team of researchers at Tufts University led by co-lead author Michael Levin, who directs the Center for Regenerative and Developmental Biology at Tufts. First, they gathered and incubated stem cells from embryos of African frogs (Xenopus laevis, hence the name “xenobots”). Finally, these cells were cut and joined together under a microscope in a close approximation of the computer-generated designs.

The team reports that the cells began working together after ‘assembly’. They developed a passive skin-like layer and synchronized the contractions of their (heart) muscle cells to achieve motion. The xenobots were able to move in a coherent fashion up to days or weeks at a time, the team found, powered by embryonic energy stores.

Later tests showed that groups of xenobots would move around in circles, pushing pellets into a central location, spontaneously and collectively. Some of the xenobots were designed with a hole through the center to reduce drag but the team was able to repurpose it so that the bots could carry an object.

It’s still alive… but on its back?

A manufactured quadruped organism, 650-750 microns in diameter.
Image credits Douglas Blackiston / Tufts University.

One of the most fascinating parts of this already-fascinating work, for me, is the resilience of these xenobots.

“The downside of living tissue is that it’s weak and it degrades,” says Bongard. “That’s why we use steel. But organisms have 4.5 billion years of practice at regenerating themselves and going on for decades. We slice [a xenobot] almost in half and it stitches itself back up and keeps going. This is something you can’t do with typical machines.”

“These xenobots are fully biodegradable,” he adds, “when they’re done with their job after seven days, they’re just dead skin cells.”

However, none of the team’s designs was able to turn itself over when flipped on its back. It’s an almost comical little Achilles’ Heel for such capable biomachines.

The manufacturing process of the xenobots.
Image credits Sam Kriegman, Douglas Blackiston, Michael Levin, Josh Bongard, (2020), PNAS.

Still, they have a lot to teach us about how cells communicate and connect, the team writes.

“The big question in biology is to understand the algorithms that determine form and function,” says Levin. “The genome encodes proteins, but transformative applications await our discovery of how that hardware enables cells to cooperate toward making functional anatomies under very different conditions.”

“[Living cells] run on DNA-specified hardware,” he adds, “and these processes are reconfigurable, enabling novel living forms.”

Levin says that being fearful of what complex biological manipulations can bring about is “not unreasonable”, and are very likely going to result in at least some “unintended consequences”, but explains that the current research aims to get a handle on such consequences. The findings are also applicable to other areas of science and technologies were complex systems arise from simple units, he explains, such as the self-driving cars and autonomous systems that will increasingly shape the human experience.

“If humanity is going to survive into the future, we need to better understand how complex properties, somehow, emerge from simple rules,” says Levin. “If you wanted an anthill with two chimneys instead of one, how do you modify the ants? We’d have no idea.”

“I think it’s an absolute necessity for society going forward to get a better handle on systems where the outcome is very complex. A first step towards doing that is to explore: how do living systems decide what an overall behavior should be and how do we manipulate the pieces to get the behaviors we want?”

The paper “A scalable pipeline for designing reconfigurable organisms” has been published in the journal PNAS.

The extracellular matrix, and how it keeps you in tip top shape

Would you live in a city without streets? Or in a flat with no walls? Probably not — and the cells in our bodies expect the same level of comfort. Today, we’re taking a look at the tissues that create and maintain an ideal working environment for our tissues: the extracellular matrix.

A mammalian trachea cross-section, magnified 200 times.
Image credits Berkshire Community College Bioscience Image Library / Flickr.

We’ve had a look at the differences between animal and plant cells before (here’s a refresher). One of the key differences between them is that plants reinforce their cells with thick, sturdy walls. These walls are why plant tissues such as wood can get so resilient. However, the reverse of the coin is that it also limits plant cells somewhat: a muscle made out of wood wouldn’t be very effective.

Animals need cells that can perform a wide variety of activities, but these cells also need biological and mechanical support to perform their tasks. That’s where the extracellular matrix, or “ECM”, comes in.

So what is it?

The ECM is a complex mix of proteins and carbohydrates that fills the spaces between cells; it is comprised of the basement membrane and interstitial matrix. Going forward, I’ll use the term ECM quite loosely to mean both ‘the extracellular matrix’ and ‘the interstitial matrix’. If I don’t mention the basement membrane specifically, I’m probably talking about the interstitial matrix (as it’s the more dynamic and frankly more interesting half of the topic).

Think of the basement membrane as a sheet of plastic wrap the body stretches over every individual tissue or organ to keep everything tidy and in place. This membrane is made up of two layers of cells and it’s quite fibrous and hard to rip.

X-ray of an elbow. The ECM in our joints (the empty volume between the bones) uses more collagen to become tough and resistant to wear.
Image via Wikimedia.

The interstitial matrix is, for lack of a better term, the goo that our cells live in. Most of the time, it looks and feels a bit like a clear gel. It’s produced by the cells themselves, which secrete and release certain compounds around them.

The simplest definition of the extracellular matrix is that it represents the sum of non-cellular components present within all tissues and organs. As we go forward, keep in mind that the ECM isn’t the same everywhere.

What’s it made of?

“Although, fundamentally, the ECM is composed of water, proteins, and polysaccharides, each tissue has an ECM with a unique composition and topology that is generated during tissue development,” Christian Frantz, Kathleen M. Stewart, Valerie M. Weaver, 2010.

Collagen, the most abundant protein in mammals, is the main component of the ECM. Outside the cell, collagen binds with carbohydrate molecules and assembles into long molecules called collagen fibrils. These fibrils extend through the ECM and lend flexibility and strength to the material, acting similarly to the role of rebar in reinforcing concrete (which is tough but inflexible). Collagen fibrils are flexible and tough to break, so they’re used to ‘bind together’ the rest of the ECM. In humans, genetic disorders that affect collagen (such as Ehlers-Danlos syndrome) cause tissues to become fragile and tear easily.

While the ECM contains a wide range of proteins and carbohydrates, another important set of compounds alongside collagen are proteoglycans (groups of proteins tied to simple sugars). Proteoglycans come with many shapes and functions, depending on which proteins and sugars they’re made of, and perform a wide range of tasks in the ECM. They can also bind to each other, to collagen (forming cartilage), or to hyaluronic acid, making them even more versatile. As a rule of thumb, proteoglycans act as fillers and regulate the movement of molecules through the ECM among other functions.

Collagen fibers in rabbit skin.
Image via Wikimedia.

Their overall structure looks like a tree: the ‘sugar’ part of the polyglycans are twigs set on a branch (the protein), which ties to a trunk made out of polysaccharide (‘many-sugar’) molecules. A class of proteins in the membranes of cells, called integrins, serve as connection ports between the membrane and material in the ECM (such as collagen fibers and proteoglycan-polysaccharide bundles). Beneath the membrane, integrins tie into the cell’s support ‘girders’ (the cytoskeleton).

The type of ECM I’ve described so far is your run of the mill variety that you’ll find in skin, around muscle fibers, in adipose tissue (fat), and so on. But each tissue has an ECM that fully supports its function — blood plasma is the interstitial matrix of blood. Unlike the ECM of muscles, for example, which is meant to reduce friction and wear in the tissue, blood plasma primarily works as a medium to carry blood cells around. Blood vessels are coated with a basement membrane, and together, they form the ECM of blood. Each type of animal connective tissue has its own type of ECM, even bone.

What does it do?

Cross-section of compact human bone, magnified 100 times.
Image credits Berkshire Community College Bioscience Image Library / Flickr.

Seeing as there are many types of ECM out there, it stands to reason that there are many functions they perform. However, by and large, there are a few functions that all ECMs fulfill.

The first and perhaps most important function is that they provide support to tissues, segregate (separate) them, and that they mediate intercellular communication. The ECM is also what regulates a cell’s ‘dynamic behavior’ — i.e. whether a cell moves around, and how. The ECM keeps cells in place so we don’t simply unravel. The connections formed between the ECM and integrins on a cell’s membrane also function as signaling pathways.

It is also essential for the good functioning of tissues at large. The ECM creates and maintains the proper environmental conditions for cells to develop, multiply, and form functioning tissues. While the exact details are still unknown, the ECM has been found to cause tissue regrowth and healing after injury. In human fetuses, for example, the extracellular matrix works with stem cells to grow and regrow all parts of the human body. Fetuses can regrow anything that gets damaged in the womb, but since babies can’t, we suspect that the matrix loses this function after full development. Researchers are looking into applying it for tissue regeneration in adults.

The ECM can also act as a storage space for various compounds. In joints, it contains more hyaluronic acid which in turn absorbs water and acts as a mechanical cushion. ECMs can also store a wide range of cellular growth factors and release them as needed. This allows our bodies to activate cell growth on a dime when needed without having to produce and ship these factors to a certain area.

It also seems to impact cell differentiation and gene expression. Cells can switch genes on or off depending on the elasticity of the ECM around them. Cells also seem to want to migrate towards stiffer areas of the ECM generally (durotaxis) from less-firm ones.

The ECM isn’t very well known today, and it definitely goes unsung. But no matter how you cut it, it is a key part of biology as we know it today. Without it, both animals and plants would be formless, messy blobs — quite literally. And I don’t know about you but I love it when my tissues stay where they’re supposed to, the way they’re supposed to.


Researchers map the genetic mechanisms that makes hydras ‘immortal’

Researchers are especially interested in hydra’s ability to regenerate its nervous system, which could new therapeutics for treating trauma or degenerative disease in humans.

Image credits Stefan Siebert / UC Davis.

The tiny freshwater invertebrate known as the hydra, while definitely less scary than its mythological counterpart, regenerates damaged cells and tissues. This ability is so poignant that, were you to cut a hydra in half, it would regrow its body and nervous system in a matter of days.

Trying to understand exactly how it does this, researchers at the University of California have traced the evolution of the hydra’s cells throughout its life, finding three lines of stem cells that differentiate into nerves, muscles, or other tissues.

Life renewed

“The beauty of single-cell sequencing and why this is such a big deal for developmental biologists is that we can actually capture the genes that are expressed as cells differentiate from stem cells into their different cell types,” says Celina Juliano, assistant professor in the UC Davis Department of Molecular and Cellular Biology and lead author of the study.

Juliano’s team sequenced RNA transcripts of 25,000 single hydra cells to follow the genetic trajectory of nearly all of the animal’s differentiated cell types. The study thus creates a high-resolution map of the entire developmental path of the hydra’s cells.

Hydras continuously renew their cells from stem cell populations, the team explains. Based on the analysis of sets of messenger RNA molecules (transcriptomes) retrieved from individual cells and groups of cells (based on shared expressed genes), the team separated these stem cells into three different lineages. They could then build a decision tree showing how each lineage matures into different cell types and tissues. For example, the interstitial stem cell lineage produces nerve cells, gland cells, and the stinging cells in the animal’s tentacles.

“By building a decision tree for the interstitial lineage, we unexpectedly found evidence that the neuron and gland cell differentiation pathway share a common cell state,” said Juliano. “Thus, interstitial stem cells appear to pass through a cell state that has both gland and neuron potential before making a final decision.”

The molecular map also allowed Juliano and colleagues to identify the genes that influence these decision-making processes, which will be the focus of future studies.

The team hopes that their work will allow developmental biologists to understand regulatory gene networks that control the early evolution of the hydra, networks that they say are shared among many animals, including humans. Understanding how the hydra regenerates its entire nervous system could thus help us better understand neurodegenerative diseases in humans.

“All organisms share the same injury response pathway but in some organisms like hydra, it leads to regeneration,” said coauthor and graduate student Abby Primack. “In other organisms, like humans, once our brain is injured, we have difficulty recovering because the brain lacks the kind of regenerative abilities we see in hydra.”

The paper “Stem cell differentiation trajectories in Hydra resolved at single-cell resolution” has been published in the journal Science.

The age of the designer protein is upon us — and the prospects are thrilling

In what could be a game-changer for therapies used in many diseases, scientists have created the first completely artificial protein switch. The protein can work inside living cells to modify or command the cell’s internal circuitry.

It’s the first fully artificial protein developed by humans. Credit: Wikipedia Commons

 

Researchers at the University of California, San Francisco used computational protein design to create self-assembling proteins that present bioactive peptides only upon the addition of specific molecular “keys.” The work was published in the journal Nature.

The research team installed the switch in yeast and showed that the genetically engineered fungus could be made to degrade a specific cellular protein at a time of the researchers’ choosing. By redesigning the switch, they also demonstrated the same effect in lab-grown human cells.

“In the same way that integrated circuits enabled the explosion of the computer chip industry, these versatile and dynamic biological switches could soon unlock precise control over the behavior of living cells and, ultimately, our health,” said Hana El-Samad, and co-senior author of the report.

The switch created by the researchers was dubbed LOCKR, short for Latching, Orthogonal Cage/Key protein. LOCKR can be ‘programmed’ to modify gene expression, redirect cellular traffic, degrade specific proteins, and control protein binding interactions – using what the paper calls ‘its arm.’

LOCKR has a structure similar to a barrel. When opened, it reveals a molecular arm that can be engineered to control virtually any cellular process. In the paper, the researchers highlight that the switch can be used to build new biological circuits that behave like independent sensors.

“LOCKR opens a whole new realm of possibility for programming cells,” said Andrew Ng of the UC Berkeley-UCSF Graduate Program in Bioengineering. “We are now limited more by our imagination and creativity rather than the proteins that nature has evolved.”

The new switch is not the first designer protein switch ever made, but it’s the first fully artificial one — and it has a lot of applications. Having access to biotechnology tools entirely conceived of and built by humans — as opposed to editing and modifying proteins found in nature — opens a range of exciting possibilities.

LOCKR gives scientists a new way to interact with living cells, which have to control their biochemical processes to avoid death or cancer. The switch could then facilitate a new array of therapies for diverse diseases, ranging from cancer to autoimmune disorders.

 

Chicken.

Researchers make chicken cells resist bird flu by snipping out a tiny bit of their DNA

Designer chicken cells grown in the lab at Imperial College London can resist the spread of bird flu.

Chicken.

Image credits Samet Uçaner.

Bird flu, as its name suggests, is mostly concerned with infecting birds. And it’s quite good at it: severe strains of bird flu can completely wipe out a whole flock. In rare cases, the virus can even mutate to infect humans, causing serious illness. As such, bird flu is a well-known and scary pathogen in the public’s eye.

Now, researchers from Imperial College London and the University of Edinburgh’s Roslin Institute have devised chicken cells that can resist infection with the bird flu virus. Their efforts pave the way towards effective control of the disease, safeguarding one of the most important domesticated animals of today.

Be-gone, flu

“We have long known that chickens are a reservoir for flu viruses that might spark the next pandemic. In this research, we have identified the smallest possible genetic change we can make to chickens that can help to stop the virus taking hold,” says Professor Wendy Barclay, Chair in Influenza Virology at Imperial College London and the paper’s corresponding author. “This has the potential to stop the next flu pandemic at its source.”

The findings could make it possible to immunize chickens to the virus using a simple genetic modification. No such chickens have been produced just yet, but the team is confident that their method will prove safe, effective, and palatable with the public in the long run.

The approach involves a specific molecule found in chicken cells, called ANP32A. Researchers at Imperial report that during a bird flu infection, viruses use this molecule to replicate (multiply) and continue attacking the host. The researchers from the University of Edinburgh’s Roslin Institute worked to gene-edit chicken cells to remove a portion of DNA that encodes the production of ANP32A.

With this little tweak, the team reports, the virus was no longer able to replicate inside the cells.

Members at The Roslin Institute have previously worked on something similar. Teaming up with researchers from Cambridge University at the time, they successfully produced gene-edited chickens that didn’t transmit bird flu to other chickens following infection. However, the approach they used at the time involved adding new genetic sequences into the birds’ DNA; while the proof-of-concept was very encouraging, the approach didn’t seem to stick, commercially.

“This is an important advance that suggests we may be able to use gene-editing techniques to produce chickens that are resistant to bird flu,” says Dr. Mike McGrew, of the University of Edinburgh’s Roslin Institute and a paper co-author.

“We haven’t produced any birds yet and we need to check if the DNA change has any other effects on the bird cells before we can take this next step.”

The paper “Species specific differences in use of ANP32 proteins by influenza A virus” has been published in the journal eLife.

Caffeine solar cell.

Researchers figure out how coffee can boost (some) solar cells

Researchers at the University of California, Los Angeles (UCLA) and Solargiga Energy in China have tried to perk up solar panels with coffee. It worked.

Caffeine solar cell.

One of the solar cells the team made using the new method.
Image credits Rui Wang and Jingjing Xue.

The team reports that caffeine can help improve the efficiency with which perovskite solar panels convert light to electricity. The finding could help them a more competitive and cost-effective alternative to silicon solar cells.

Wakey, wakey

“One day, as we were discussing perovskite solar cells, our colleague Rui Wang said, ‘If we need coffee to boost our energy then what about perovskites? Would they need coffee to perform better?'” recalls Jingjing Xue, a Ph.D. candidate at the Department of Materials Science and Engineering at UCLA and co-lead author of the study.

After, presumably, a few rounds of hearty laughs, the team set their cups down and set to work on trying to see if the idea has any value.

The authors have previously worked on improving the thermal stability of perovskite materials — the blue compounds with a particular crystal structure that forms the light-harvesting layer certain solar cells — to make them more efficient at harvesting sunlight. Part of that work involved trying to strengthen the material with additives such as dimethyl sulfoxide, an approach which showed some success in the short term, but wasn’t stable over longer spans of time. Caffeine, however, is an alkaloid compound whose molecular structures could, the team suspected based on their previous experience, interact with the precursors used to make perovskite materials.

So, they set out to add caffeine to the perovskite layer of forty solar cells and used infrared spectroscopy, an approach that uses infrared radiation to identify a sample’s chemical components, to determine if the materials bonded. They had.

Further infrared spectroscopy tests showed that carbonyl groups (a carbon atom double bonded to an oxygen) in caffeine tied to lead ions in the perovskite layer to form a “molecular lock”. This lock increases the minimum amount of energy needed for the perovskite layer to react to sunlight, boosting the solar cell efficiency from 17% to over 20%. This lock stood firm when the material was heated, which suggests that caffeine could also help to make the solar cells more thermally-stable.

“We were surprised by the results,” says Wang, who is also a Ph.D. candidate in Yang’s research group at UCLA. “During our first try incorporating caffeine, our perovskite solar cells already reached almost the highest efficiency we achieved in the paper.”

The caveat, or caffeat if you so prefer, is that this approach likely won’t work with other types of solar cells. It only works here because it can tie into the unique molecular structure of perovskite precursors. However, it may be enough to give this type of solar cell variety an edge on the market.

Currently, perovskite solar cells are the cheaper and more flexible option available on the market. They’re also easier to manufacture, as they can be fabricated from liquid precursors — their silicon counterparts are cast from solid crystal ingots. Wang believes that caffeine might make them even easier to fabricate on a large scale, in addition to making them more efficient.

“Caffeine can help the perovskite achieve high crystallinity, low defects, and good stability,” he says. “This means it can potentially play a role in the scalable production of perovskite solar cells.”

The team plans to continue their efforts by investigating the chemical structure of the caffeine-infused perovskite crystals and identify what materials would best serve as a protective layer for the solar cells.

The paper “Caffeine Improves the Performance and Thermal Stability of Perovskite Solar Cells” has been published in the journal Joule.

Hyaluronic acid.

What is hyaluronic acid

Your average 70 kg (154-pound) person has around 15 grams of this substance in their body. Roughly one-third of it breaks down and replenishes daily. This high turnover rate suggests that hyaluronic acid — also called hyaluronan or hyaluronate — is quite important for our well being.

But what is this hyaluronic acid? Let’s find out.

Hyaluronic acid.

 

The basics

Hyaluronic acid, when you boil away all the bells and whistles, is a really long polymer molecule. It’s basically a long chain made up of thousands of sugar molecules. It is found throughout the cells in your body but only occurs in high concentrations in certain areas. It also serves a different role in various tissues and cells.

For example, hyaluronan acts as a building block for cellular membranes (their ‘walls’). It’s also found in cartilage, especially in those joints at the end of long bones, where it reduces wear and tear on the tissue and serves to absorb shock (in the form of an oil-like ‘synovial liquid’). The acid also lubricates active tissues such as muscle and cartilage. As a rule of thumb, the compound is either used to keep tissues running or to give them resilience and flexibility. It has an important part to play in skin health, wound healing, cell mobility, building tissues that insulate other tissues, and keeping the fluids in your eyes gooey. The vitreous humor inside your eyeballs is almost completely made up of hyaluronic acid.

Hyaluronic acid is extremely hydrophilic (it absorbs water), and it’s this property that allows it to function as a lubricant in our bodies. It can absorb up to 1000 times its weight in water. All that water it holds also makes it an excellent moisturizer.

Calf eye vitreous humor.

Anterior view of a dissected calf eye. The transparent goo is the vitreous humor.
Image credits: Mark Fickett / University of Pennsylvania.

It looks like a transparent gel and has the consistency to fit its look. To give you a rough idea of how hyaluronic acid looks, feels, and behaves, Endre Balazs — a doctor and professor of medicine who spent seven decades of his life studying the compound — tried to patent hyaluronic acid as a bakery substitute for egg white in 1942. He was granted the patent and went on to become a leading research figure on the matter of hyaluronic acid and its uses.

In the skin

One of the main jobs hyaluronic acid has to do is to act as the mortar between our cells. It keeps us together in the correct shape.

In biology, that mortar is called the extracellular matrix (ECM) and it is a gelatinous fluid which surrounds almost every one of our living cells. The ECM is made up of fibrous elements (generally elastin and collagen) affixed in a gelatinous substance — hyaluronic acid. It’s this acid’s job of keeping the ECM stretchy and hydrated, and it also ferries nutrients and waste between these structures and the rest of the body.

The skin, bones, tendons, ligaments, and cartilage are among the tissues richest in ECM. The skin takes the hyaluronic cake, as it contains roughly 50% of our body’s total of the compound. Skin needs a lot of it because it has to stretch without breaking, as well as bend and then bounce back. The acid doesn’t do that itself — that’s collagen’s job — but it does keep those collagen fibers hydrated and in tip-top shape. If you want to see how hyaluronic affects the skin, just wait 20, maybe 30 years: our skin loses some of its ability to produce the acid as we age.

Bereft of its hyaluronic acid, our skin loses the ability to hold water and, thus, to properly hydrate itself and its collagen. On the one hand (and every other bit covered by skin), this makes it drier and less flexible. The acid, which basically works to store water in a gooey state, also acts as a filler agent, keeping the skin free of wrinkles. So, on the other hand, aging also makes our skin wrinkly.

In medicine and beauty products

Hand cream.

Image via Pixabay.

Hyaluronic acid saw its first recorded medical use in 1943, during the height of the Second World War. Nickolay Gamaleya used it to create complex bandages for the treatment of frostbitten soldiers at the Soviet field hospital nr. 1321, according to Hyaluronic Acid: Production, Properties, Application in Biology and Medicine. Gamaleya christened the hyaluronic acid in those bandages, the book notes, as the “factor of regeneration”. The compound was so effective that it was later approved by the USSR’s Ministry of Health under the name ‘Regenerator’ — only in Russian, one would assume.

A number of somewhat exotic uses for hyaluronan followed: as a prosthesis for the treatment of retinal detachment, to prevent post-operatory tissue soldering, to heal the aching joints of racehorses suffering from arthritis, and even to help with implanted ocular lenses.

Today, people take hyaluronic acid for various joint disorders, such as osteoarthritis. The FDA has also approved its use during certain eye surgeries such as cataract removal, corneal transplantation, and repair of a detached retina. It is injected into the eye during such procedures to help replace fluids such as the vitreous humor. It’s also mixed into some skin-applicable products intended to promote healing of wounds, burns, or skin ulcers. Note, however, that there is only limited clinical evidence for its effectiveness in this role.

Plastic surgeons and their patients are also big fans of hyaluronic acid. It’s often used as a filler — just like its natural role — in plastic surgery, in procedures to make lips fuller or to reduce wrinkles, for example. It also sees a lot of use as a moisturizer in various creams.

Some people may be eager to sell hyaluronic acid to you as the be all end all ‘fountain of youth’. While it does seem to have a moisturizing effect — which definitely helps your skin shine — there is no evidence to support the view that this compound actually prevents or undoes changes associated with aging.

Whether you take it by mouth or apply it on your skin, its effects on wrinkles seem to be only skin deep.

Bee experiment.

Bees use a small number of neurons to count, and they’re one of the best counters we know

Not only can bees count — but they can do so using laughably few brain cells.

Bee in approach.

Image credits Christian Birkholz / Pixabay.

One team of researchers from the Queen Mary University of London looked into how bees count. The insects, they report, draw on a brain-wiring trick to allow them this skill using very small numbers of neurons. In order to understand how bee brains handle numbers, the team simulated an extremely simple brain network on a computer.

Despite containing just four neurons (far fewer than a real bee can boast), this artificial brain could still handle the task. Lab results showed that it could easily count small quantities of items when inspecting one item closely and then inspecting the next item closely and so on, which is the same way bees count. This differs from humans who glance at all the items and count them together.

Counting bee

Previous research has shown that bees can count — usually up to four or five items. Interestingly enough (and perhaps, uniquely among non-humans), they can also grasp the concept of zero when trained to choose ‘less’.

However, new research reveals something really surprising: it’s possible that bees have no clue what numbers (or other numerical concepts) are. By using specific flight movements to closely inspect items, the bees draw on their visual input to simplify the task of counting so much, it requires minimal brainpower. This shows that the intelligence of bees (potentially other animals’ as well) can be based on a very small number of nerve cells, as long as these are wired together in the right way.

“Careful examination of the actual inspection strategies used by animals might reveal that they often employ active scanning behaviours as shortcuts to simplify complex visual pattern discrimination tasks,” says lead author Dr Vera Vasas, from Queen Mary University of London. “Hopefully, our work will inspire others to look more closely not just at what cognitive tasks animals can solve, but also at how they are solving them.”

She goes on to explain that although counting is generally considered to “require high intelligence and large brains,” the findings show it can be done with a small — but properly-structured — network.

“We suggest that using specific flight movements to scan targets, rather than numerical concepts, explains the bees’ ability to count. This scanning streamlines the visual input and means a task like counting requires little brainpower.

Bees only have about one million nerve cells overall, meaning they have really, really low brainpower (no offense, bees). Your average human, for example, boasts upward of 86 billion nerve cells.

Still, this limitation forced evolution to get creative, and it did. The bees overcome their relative lackluster hardware with fancy computational algorithms, the team reports. To model how these tiny insect brains receive information, the team analyzed the point of view of a bee as it flies close to the countable objects and inspects them one-by-one.

Bee experiment.

A bumblebee choosing between two patterns containing different numbers of yellow circles.
Image credits Lars Chittka.

This data was later fed to the simulated brain. It made reliable estimates of the number of items on display based on this video feed, the team reports — in essence, it could count. As such, the findings could also have implications for artificial intelligence.

“These findings add to the growing body of work showing that seemingly intelligent behaviour does not require large brains, but can be underpinned with small neural circuits that can easily be accommodated into the microcomputer that is the insect brain,” says lead author Professor Lars Chittka, also from Queen Mary University of London.

The paper “Insect-inspired sequential inspection strategy enables an artificial network of four neurons to estimate numerosity” has been published in the journal iScience.

Skin old, new.

Stem-cell-laden skin grafts could heal burn victims 30% faster, if not quicker

It’s the phoenix of skin grafts!

Skin old, new.

Image via Pixabay.

Researchers at the University of Toronto (UoT) are working to give burn victims their skin back. The team has developed a new process by which stem cells are retrieved from the burned skin and used to speed up recovery. Such a treatment option would greatly improve the chances of survival for those involved in fires or industrial accidents, as well as their quality of life to boot.

The team plans to start human trials by early 2019.

Skin to ashes, ashes to skin

“Because we’re using actual skin stem cells, and not from some other part of the body, we believe the quality of the skin will be better,” says Saeid Amini-Nik, a professor in the UoT Faculty of Medicine

“You want skin that stretches normally. In burn patients skin gets scarred and they have trouble moving joints because skin is not elastic.

Current procedures call for the removal and discarding of burned skin as medicinal waste. Collagen dressings are then applied to the site to protect the injury while it’s healing. This can take up to several months, however, during which patients are at high risk of developing (often fatal) infections.

Given the limitations of the current approach, researchers have long been interested in using stem cells to heal burns. Such cells were harvested from samples of organs from themselves or other patients/donors (such as umbilical cords, for example), which comes with its own host of problems:

  • Tissue incompatibility, leading to high rejection rates for the grafts.
  • Difficulties harvesting stem cells from the patients themselves. The cells used in such treatments are most often derived from undamaged portions of a patient’s skin or bone marrow. However, burn victims who need treatment with their own stem cells are usually those who have suffered extensive injuries — usually covering more than half of their bodies. Their extensive burns already pose a significant, potentially fatal risk, and they’re already at a high risk of infection. Surgically removing the skin or marrow needed for the treatment thus poses a real risk to their survival.

The team’s new approach started with them looking for live stem cells in samples of discarded dermis taken from burn victims. It was virtually unheard-of up to now, as it was considered a fool’s errand. The UoT researchers themselves hoped to find even one living cell in such samples — they were astonished to find thousands (even a million in one case) of living, usable cells in the burned tissue.

A preclinical trial involving animal models showed that adding human dermis stem cells to the collagen dressings improved healing speeds by 30%. There were no cases of rejection, and the stem cells naturally created skin to cover the wounds. The team hopes to see higher regrowth rates in the upcoming human trials, as they will be using human cells on people.

Cardiac stem cells.

Cardiac stem cells.
Image credits Gepstein Laboratory.

Amini-nik says the team expects the healing process to happen “very fast, possibly days instead of weeks or months,” which would be grand. Speed is key in healing burns, as each day spent with open wounds that need fresh dressings increases the chance of developing an infection — the baseline risk is already very high, and “sometimes [patients] die of sepsis.

Another major plus is that “using a patient’s own stem cells also won’t raise ethical issues,” the team explains.

“Much faster healing would be a major step forward,” says Amini-Nik. “We also believe this will be better for quality of life: Itching and inability to sweat are big problems for burn patients. We believe if we use the stem cells from the very same organ, we’ll grow better skin. ”

“Our goal is no death, no scar, and no pain,” adds Marc Jeschke, paper co-author. “With this approach we come closer to no death and no scar.”

The paper “Stem cells derived from burned skin – The future of burn care” has been published in the journal EBioMedicine.

Pancreatic cells islets.

Pancreatic cells can naturally morph to combat diabetes, pointing to new avenues of treatment

An old cell can learn new tricks!

Pancreatic cells islets.

Dyed cells in a pancreatic islet.
Image credits Xiaojun Wang et al., (2013) PLOS One.

New research reveals a surprising level of plasticity in pancreatic cells, which morph to maintain proper hormone levels in the blood. The findings suggest that many other specialised cells could hold this ability, pointing the way to new treatment options for conditions that involve massive cellular death.

Class reroll

“What we are showing here is that the state of differentiation of a given cell is not carved in stone. Cell identity, at all stages of life, is modulated by the immediate cellular environment, particularly by inhibitory signals,” says lead author Professor Pedro Herrera from the Université de Genève (UNIGE) Faculty of Medicine. “Cell identity maintenance is therefore an active process of inhibition throughout the life of the cell, and not an intrinsic or passive state of differentiation.”

“This ability of specialized cells to change their function could prove crucial for treating other pathologies that are due to massive or inappropriate cell death, such as Alzheimer’s disease or myocardial infarction”.

The research was born of the team’s interest in diabetes, a disease that involves damage or destruction (through various means) of insulin-producing cells in the pancreas. This dismantles our bodies’ ability to regulate blood-sugar levels, leaving an excess in the blood over long periods of time, which leads to all sorts of complications: blindness, kidney failure, heart attacks, stroke, to name a few. Onset of diabetes is strongly linked to lifestyle. According to the WHO, over 8.5% of adults worldwide suffered from diabetes (both types combined, figures for 2014) and roughly 1.6 million deaths were directly caused by diabetes in 2015. Needless to say, it’s a wide-reaching condition with a severe quality of life impact — so there is a lot of interest in finding a cure.

Pancreatic cells involved in blood-sugar regulation come in three flavors: α (alpha) cells which produce glucagon, β (beta) cells which produce insulin, and δ (delta) cells which produce somatostatin. These cells bunch together in small clusters known as pancreatic islets. Glucagon raises sugar levels in the blood, insulin works to reduce it, and somatostatin is the hormonal equivalent of a manager’s email, governing activity in the pancreas. Diabetes is characterised by the absence of functional β cells, taking away the pancreas’ ability of reining in blood sugar.

In a study published back in 2014, however, Herrera and his colleagues showed that some pancreatic cells can switch their role to supplement the production of insulin if push comes to shove. In mice without β cells, they reported at the time, new insulin-producing cells appear spontaneously. However, it’s not a huge number — only “1 to 2% of α and δ cells”, Herrera explains, —  way too few to fix diabetes.

“Why do some cells do this conversion and others not? And above all, would it be possible to encourage it? These are the questions that are at the heart of our work,” Herrera adds.

To get to the bottom of things, the team analysed gene expression in pancreatic cells before and after the disappearance of β cells in pancreatic tissue. The first finding was that α cells suffer two key modifications: they start over-expressing some genes typically seen in β cells, and some that are characteristic for glucagon-producing α cells. Herrera’s team reports that insulin receptors on the surface of α cells suggests that their functions hinge on this hormone being present as well — hence, their activity is disrupted when β cells are destroyed.

Next, the team transplanted pancreatic islets into healthy mice to see what could coax these cells into morphing. Their hypothesis was that, when faced with hyperglycemia (high blood-sugar), α cells would change roles to address the lack of insulin.

In non-diabetic mice with functional β cells, and without hyperglycemia, some of the transplanted α cells started producing insulin when the β cells died in the grafted islets. This pretty much invalidated the team’s hypothesis, as a conversion was observed without hyperglycemia to act as a cue. The pancreatic environment itself was ruled out as a cause, too, as the grafts were placed in the renal capsule (i.e. outside of the pancreas). The only explanation, the team adds, is that the reprogramming capacity is intrinsic to the very pancreatic islet where these cells are located.

“Thus, in the same graft, only islets without β cells displayed reprogramming. No cell conversion occurred in neighbouring islets containing all their β cells,” says Herrera.

When the team blocked the insulin receptors of α cells in healthy mice, some of them started to produce insulin themselves — suggesting the hormone acts as a sort of ‘business as usual’ signal for α cells, preventing them from changing roles.

“By administering an insulin antagonist drug, we were able to increase the number of α cells that started producing insulin by 1 to 5%. In doing so, these cells became hybrids: they partially, but not fully changed their identity, and the phenomenon was reversible depending on the circumstances influencing the cells. Now that we are beginning to understand the mechanisms of this cellular plasticity, we believe that these adaptive cell identity changes could be exploited in future new treatments,” Herrera concludes.

While the work focused on pancreatic cells, there’s no reason why other specialised cells in the body couldn’t employ similar processes, the team says. More work will be needed to determine which cells can morph this way, and what would encourage them to do so — but, should we succeed, it could lead to new and very powerful treatments against conditions that involve cellular damage and death.

The paper has been published in the journal Nature Cell Biology.

What the season of fall – and science – teaches us about life and death

Credit: Pixabay.

I was launched as one; and ended up being trillions of them. The cells composing my body are amazing micro-machines; one hundred of them can fit into the period at the end of this phrase. Regardless of my awareness, each of these teeny tiny units strictly performs its own intricate duties: breathing in oxygen and secreting out carbon dioxide, multiplying by splitting into two, migrating around or idling for a while, and ultimately maturing to lay down the specific type of supporting structure known as matrix. The matrix surrounds the cell and sustains its specific function – like soft matrix for skin and hard matrix for bones or teeth.

A cell even has its own brain or, if you will, control panel: the nucleus. This nucleus contains the instructions for building a cell and an entire individual. This four-letter code, known as DNA and measuring 2 meters long from a single nucleus, dictates every single programmed task the cell performs during its life.

Interestingly, the function of a cell does not end at maturation or when it finishes secreting the matrix. The cell’s function is only complete after its final task which is, amazingly, to die: programmed cell death. The term “programmed” describes the organized, planned and careful dismantling of the cell’s components rather than a sudden unpredictable ruination.

Carefully dismantling life

The planned process could be compared to the careful disassembly of a Lego castle. In contrast to the instant gravity-driven wreckage on the ground, pieces are taken off and organized back into their original slots to be eventually reused and reassembled into another complex construction. This organized and programmed “ending” of the life of a cell was sensibly given the biological term “apoptosis” – from Greek “apo,” which means off/away, and “ptosis,” which means dropping, referring to the falling leaves.

What is more intriguing than the apoptosis process itself is the analogy behind its name. During autumn, leaves dry and fall off the tree. Despite leaving an obvious leafless and seemingly lifeless structure, it is only by shedding its leaves that the tree can survive the windy and sun-deprived winter, when sudden gusts could blow down a tree laden with a large surface area of leaves.

In other words, dismissing its leaves before winter, the tree prepares to reduce wind resistance and to save energy to re-blossom in the spring.

The death of the part – the leaf – as sad as it may seem, is for the sake of the life of the whole tree. If leaves do not leave (is that where their name comes from?!), the whole tree will die, taking with it the lingering leaves. Similarly, the apoptosis of a cell is a necessary sacrifice to preserve the life of the whole body.

Life goes on …

Taking our bones as an example, the balance between the newborn and dying cells is the key to the natural turnover for our healthy skeleton. In fact, about 10 percent of our bone mass is renewed every year with cells dying and new ones taking their place. When the balance of this process is disrupted, disease results. Too many dying cells leads to the loss of bone mass, such as in a condition known as osteoporosis, which means porous bones. Too many new cells leads to bone tumors. Having their programmed death gone awry, cells multiply indefinitely and uncontrollably – a condition known as cancer – which sets the whole body to an eventual death.

On different scales – the leaf for a tree, the cell for the body, the individual for the society – what we perceive as death is actually an act of carrying on life. Mourning the separation from our beloved inevitably, and rightfully, overrides our understanding – or rather the inability to understand – death, life’s plainest and most puzzling fact and inescapable fate.

All of us will eventually drop off the tree. In fact, birth could ironically be regarded as the primary predisposing factor for death; the only guarantee not to fall off is not to get seeded in the first place.

Before it is too late

Having experienced wet eyes, I am not trying or daring to make the departure of our beloved ones into a soothing scientific technicality or underestimate the associated feelings. Indeed, despite what we can learn from trees, we are not trees: Feelings are an integrated part of our existence and are what makes us human.

Ruth McKernan, a British neuroscientist who studies how our brain functions, having struggled through the moments of her father’s agony and endured the grief of separation, puts it this way in her book “Billy’s Halo”: “That is science and that is real life. At the moments of separation, all the theory doesn’t make it easier to bear.”

This fall, while contemplating the panoply of the fall colors and the leaves dropping, let us remind ourselves to cherish our seniors while they are around. Acknowledging that our comfort and joy are not synonymous, let us serve them with appreciation for what they have contributed in our lives.

Remembering who have passed, let us celebrate their legacy that paved the way to new blossoming generations; and certainly we shall mourn our beloved who have prematurely left. Let us decide to do the best we can, wherever and whenever we can for our family, friends, coworkers and all our fellow “leaves” in society as long as we are still connected to its branches.The Conversation

Samer Zaky, Research Assistant Professor, University of Pittsburgh

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Artificial bacteria-killing cells could win the war against drug resistance

Research at the University of California, Davis, has resulted in artificial cells that cannot grow or divide but will unleash a can of whoop-ass on any bacteria they encounter.

The artificial cells mimic some of the properties of living cells but don’t grow and divide.
Image credits Cheemeng Tan / UC Davis.

Although researchers have successfully created artificial cells in the past, they remained stable only in certain conditions. The key limitation was that these cells could only survive in nutrient-rich environments, as they lacked the capacity to feed themselves.

The advancement this present paper reports on is that the team’s “lego block” artificial cells can survive and work in a wide variety of conditions with limited resources. This greater self-sufficiency was achieved by the team’s efforts in refining the cells’ membranes, cytosol (the ‘soup’ inside cells), and their genetic material.

Teeny-weenie death machinie

“We engineered artificial cells from the bottom-up — like Lego blocks — to destroy bacteria,” said Assistant Professor Cheemeng Tan, who led the work.

“We demonstrated that artificial cells can sense, react and interact with bacteria, as well as function as systems that both detect and kill bacteria with little dependence on their environment.”

The cells are built from liposomes — bubbles with a cell-like lipid membrane — and purified cellular components including proteins, DNA, and assorted metabolites. They have all the fundamental components of live cells, but they’re short-lived and cannot divide, so they can’t make more of themselves.

The cells were forged with a purpose, however — to beat up E. coli bacteria. By tweaking their genetic material, the team designed these cells to pick up on and react to a unique chemical signature given off by E. coli. Laboratory tests showed that once these artificial cells pick up on the scent, they will attack and destroy all E. coli in a culture.

As the cells are much more robust and self-sufficient than previous ‘models’, they can be employed even in less-than-ideal or changing conditions. This enables them to have a much broader scope of potential applications compared to any other artificial cells currently at our disposal.

The team has high hopes for their spawn. The researchers envision using these cells in an antibacterial role, injecting them into patients suffering from infections resistant to conventional treatments. Alternatively, they might be used for targeted delivery of drugs at specific locations and times, or as biosensors.

The paper “Minimizing Context Dependency of Gene Networks Using Artificial Cells” has been published in the journal Applied Materials and Interfaces.

Immune cell gif.

Amazing video shows how white blood cells find pathogens — and points to a cure against cancer

Using cutting-edge microscopy imaging, researchers discovered — and filmed — the ‘sensors’ macrophage cells use to detect pathogens. The research might also yield one of the most powerful tools to date in the fight against cancer.

Immune cell gif.

Image credits University of Queensland / Youtube.

Macrophages form the first line of defense in our immune systems, patroling tissues throughout our bodies and guarding the bits susceptible to infection. Once a macrophage encounters something that doesn’t wear the protein tags of healthy human cells — such as cellular debris, pathogens, cancer cells, or foreign substances — the cell wraps around it and proceeds to digest it.

Still, despite decades of research, we still barely understand how macrophages — and their other white cell relatives — work. In an effort to patch our grasp of these mechanisms, a team from the University of Queensland (UQ) used cutting-edge microscopy techniques to film macrophage cells.

Their research led to the discovery of structures known as “tent-pole ruffles”, which underpin the cells’ functions. The same structures, the team writes, may help us find a new and very powerful tool against cancer.

If you can’t beat them, eat them

“It’s really exciting to be able to see cell behaviour at unprecedented levels of resolution,” says co-author Adam Wall, a researcher in molecular bioscience at UQ.

“This is discovery science at the cutting edge of microscopy and reveals how much we still have to learn about how cells function”.

The ruffles are located on the surface of macrophages, a specific type of white blood cell that directly engages pathogens and other undesirables in our bodies. Tent-pole ruffles underpin their function, the team writes, by allowing the cells to sample their surrounding fluids for potential threats.

Tent pole ruffles.

How tent-pole ruffles work — video below.
Image credits Nicholas D. Condon et al., 2018, JCB.

They take the name from their shape and work similarly to our sense of taste or smell: the ruffles extend from the cell’s body and — using a special membrane strung between the poles — gather relatively large volumes of fluid that are then sampled for chemical markers. This process is known as ‘macropinocytosis’. If any molecules from a foreign entity are detected, the cells move towards the source and prepare to engage.

Tent-pole ruffles are exceedingly small. Their discovery was only made possible by a new imaging technology known as ‘lattice light sheet microscopy’. The technique can capture tiny structures in a matter of seconds, generating stunning 3D renditions with very high precision.

“This imaging will give us phenomenal power to reveal how cell behaviour is affected in disease, to test the effects of drugs on cells, and to give us insights that will be important for devising new treatments,” says study supervisor Jenny Stow, a deputy director of research in molecular bioscience at UQ.

It’s a very fortunate development. The research helps us better understand how our immune systems scrub the body clean of pathogens, but it also points to a way to cripple cancer cells. These latter cells use the process of macropinocytosis to capture nutrients, not to probe their environment like the macrophages. Apart from that, the process works largely the same — tent-pole ruffles extend, the membranes capture field, and nutrients are absorbed.

In theory, then, if researchers can figure out how to destroy or inactivate the tent-pole ruffles of cancer cells, we could simply starve them out.

The team plans to continue using lattice light sheet microscopy to probe the natures of other human immune system cells.

The paper “Macropinosome formation by tent pole ruffling in macrophages” has been published in the Journal of Cell Biology.

Cancer tumor mice model.

Denying cancer cells one key amino acid might destroy treatment-resistant tumors

Oxygen-starved tumors have a hard time producing one key amino acid — and researchers hope further denying them this compound could help us fight cancer.

Cancer tumor mice model.

In this tumor, imaged in a mouse model of breast cancer, oxygen-low areas appear in green. These regions tend to resist standard cancer treatments.
Image credits Laboratory of Metabolic Regulation and Genetics / The Rockefeller University.

Tumors are clumps of rogue cells that don’t do much beyond just growing and gobbling up resources. Still, these freeloaders eventually become deadly, as their rampant growth impact our bodies’ ability to function.

However, new research hopes to turn cancer’s prolific growth against it. As tumors grow and drain resources from the body, they place a strain on oxygen. When this happens, the tumors basically start to suffocate. A new paper published by researchers from the Laboratory of Metabolic Regulation and Genetics (LMRG) at The Rockefeller University suggests that denying tumors aspartate, a key amino acid whose synthesis hinges on oxygen, could help fight the disease.

The bottleneck

The team, led by  Kivanç Birsoy, head of the LMRG, suggests that doctors could target oxygen-starved tumors with drugs that impede their ability to synthesize or absorb aspartate in a bid to kill these cells.

The research was built on previous findings that tumors tend to out-grow the host body’s ability to provide them with oxygen and when this happens, they grow more slowly. We didn’t know exactly why this happens, however, as oxygen is a key component in a plethora of cellular reactions — any one of them could have an impact on cells’ ability to grow.

In order to uncover the underlying process, the team mimicked oxygen deprivation in samples of cancer cells harvested from 28 patients. The cells included blood, stomach, breast, colon, and lung cancers — the most often-seen kinds — which were cultured in Petri dishes in the lab after harvesting.

Many of these cells couldn’t properly grow and develop in the low-oxygen-like conditions, the team reports. Others, however, were less sensitive; some didn’t seem to mind at all. So the team set out to compare their metabolites (the chemicals cells generate as part of their normal life cycle) to understand why.

D-Aspartate.

Dextro-Aspartate.
Image credits D.Azani / Wikimedia.

The common denominator between all the cells that did struggle was a lack of aspartate, the researchers found. Aspartate is an amino acid involved in several key processes, from protein production to synthesis of genetic material. While none of the cells could produce aspartate without oxygen, some could get around it — for example, by sucking it up from their environment. Cells that managed even when deprived of oxygen did so by activating a gene called SLC1A3 that drew in aspartate.

Birsoy says he was surprised that so much of the woes these cells have when deprived of oxygen come down to a single compound. When starting out the study, the team expected to find a network of processes or end compounds that hinge on oxygen as the culprit.

To make sure they were on the right track, the team activated SLC1A3 in the cancers that were sensitive to low oxygen; they started growing faster. The modified cancer cells kept their perkiness when transplanted into mice models, further reinforcing the findings’ validity.

It’s excellent news, however — it’s much easy to deny cells a single compound than a range of compounds.

Armed with these findings, researchers can tailor drugs to hit cancer cells at their most vulnerable place — their need for aspartate, the team writes. Any way we can go about this, either by blocking synthesis or absorption from the host, should help. If later trials prove that the approach is effective in treating tumors in humans, anti-aspartate treatments could be used alongside chemotherapy and radiation treatments in fighting tumors.

Even better, tumors in oxygen-starved areas tend to be resistant to both chemotherapy and radiation treatment, the team notes — so the anti-aspartate treatment could help us fight a problematic type of tumors. Birsoy hopes his findings will lead to a two-pronged approach to cancer: one part of the treatment to deal with tumors that have oxygen aplenty, and the aspartate blocker to mop up the rest.

Still, such a combined treatment won’t be available anytime soon. For starters, we don’t even know what drugs we could employ to deny these cancer cells their aspartate. Birsoy says his team will focus on finding such compounds next.

The paper “Aspartate is a limiting metabolite for cancer cell proliferation under hypoxia and in tumours” has been published in the journal Nature Cell Biology.

Moon footprint.

Mock lunar dust kills cultured cells, alters DNA — raising concerns about the real thing’s toxicity

Don’t forget to dust off your spacesuit if you go trekking out on the Moon — else you might risk cellular and DNA damage.

Moon footprint.

Footprint made by Buzz Aldrin during the Apollo 11 mission.
Image credits NASA.

A new study has revealed one more thing we’ll have to plan for when and if we decide to settle on the moon: lunar dust can be quite harmful if inhaled. While this isn’t the first signs we’ve seen of moon dust causing trouble for humans — Apollo mission astronauts complained of sneezing and watery eyes after bringing the stuff into their ships on spacesuits — this is the most thorough look at the health risk it poses.

Dust out

“Very small particles in the breathable range or smaller can interact directly with cells,” Bruce Demple, a professor at the Stony Brook University School of Medicine and the study’s corresponding author told Gizmodo.

The study, unfortunately, didn’t involve sending anyone to the Moon. Instead, the team cultivated human lung and mouse brain cells in Petri dishes in a lab, then exposed them to simulated lunar dust. The team reports that the substitute could damage or outright kill cells, as well as compromise the integrity of their genetic material. Up to 90% of human lung cells and mouse neurons died when exposed to dust particles that mimic soils found on the Moon’s surface.

The dust was especially dangerous to living tissue when crushed down into small, micrometer-sized bits.

One interesting find is that it’s not the dust’s chemical interactions with cells — which the team gauged by its ability to generate free radicals — that caused the damage. They’re not exactly sure what does, however. Demple suspects the way these dust particles are shaped might have something to do with it. Past research has looked into using physical rather than biochemical defenses against bacteria, and some animals also sport similar defenses, so Demple’s theory isn’t as far-fetched as it may first seem.

Moon-dust-montage.

Pieces of moon dust under the microscope.
Image credits NIST.

All in all, though, it’s not the best of news. Moon dust is much drier than the one we’re used to seeing down here and likely to be electrostatically charged, on account of there being no atmosphere, the paper notes. Last but not least, it’s also likely composed of much tinier particles — ground down by billions of years of meteorite bombardments. In other words, lunar dust has a tendency to be drawn to and stick to everything. It’s also tiny enough to bypass most filters and be a nuisance for some seals. Together, these properties would make dusting off spacesuits and equipment an exercise in frustration.

Given how dangerous this dust may be to living cells, this might become quite a health hazard for potential lunar colonists. The team reports that long exposure to the dust could lead to bronchitis or other health problems. The hay-fever-like symptoms the Apollo astronauts experienced suggests that longer exposure to the dust could impair airway and lung function, Demple explains. If the dust also causes inflammation in the lungs, it could increase the risks of diseases such as cancer.

“If there are trips back to the Moon that involve stays of weeks, months or even longer, it probably won’t be possible to eliminate that risk completely,” Demple adds.

Still, the results aren’t conclusive as of now. The study itself is quite limited since it used a moon dust substitute, as the original wasn’t available and quite hard to reach. Cultured cells are also a poor substitute for the complexity of a whole, living organism. However, it does suggest that dust from the moon could pose a serious threat to health, a finding that is supported by previous research. Dismissing the findings outright based on the study’s limitations would thus be quite foolish.

The team is fully aware of these shortcomings, but they hope that the results will convince NASA to let them work with real lunar dust, recovered by the Apollo missions.

The paper “Assessing Toxicity and Nuclear and Mitochondrial DNA Damage Caused by Exposure of Mammalian Cells to Lunar Regolith Simulants” has been published in the journal GeoHealth.

Cells printer.

Newly-developed 3D printing method uses cells, biomolecules to recreate tissues

UK researchers have developed a new 3D printing technique — but this press prints not in plastic, glass, or metal, but rather in cells and molecules you’d normally find in living tissue.

Cells printer.

Cells spreading on the outside of 3D-printed scaffold.
Image credits Clara Hedegaard.

Ever felt the need for a piece of living matter but without all the messy “organism” part that just complicates everything? Well, you’re in luck, because a team from the Queen Mary University in London has developed a 3D printing technique “capable of encapsulating and spatially distributing multiple cell types within tuneable pericellular environments.”

The process embeds cells and other molecules in an ink that simulates conditions inside living organisms. Because of this, the building blocks used in printing can behave largely as they would in the body, allowing researchers to explore new avenues of study for biological structures.

“The technique opens the possibility to design and create biological scenarios like complex and specific cell environments, which can be used in different fields such as tissue engineering by creating constructs that resemble tissues or in vitro models,” says Professor Alvaro Mata, the paper’s corresponding author. “[These constructs] can be used to test drugs in a more efficient manner.”

The technique actually mixes two ‘printing’ styles together: molecular self-assembly, described in a university press release as “building structures by assembling molecules like Lego pieces”, and additive manufacturing, the layer-upon-layer approach used in more traditional 3D printing.

Using the two processes in tandem allows the researchers to digitally design and then manufacture structures “with molecular precision” while creating cells and other bioconstructs that mimic tissues or whole body parts.

“This method enables the possibility to build 3D structures by printing multiple types of biomolecules capable of assembling into well defined structures at multiple scales,” says lead author Clara Hedegaard.

“Because of this, the self-assembling ink provides an opportunity to control the chemical and physical properties during and after printing, which can be tuned to stimulate cell behaviour.”

The research addresses a major shortcoming of current 3D-printing techniques: a very limited capacity to stimulate the cells that are being printed, the authors note. The structures printed using this new method hold promise as test-bed-tissues for tissue engineering or regenerative medicine.

The paper “Hydrodynamically Guided Hierarchical Self-Assembly of Peptide-Protein Bioinks” has been published in the journal Advanced Functional Materials.

Cell dividing.

The difference between prokaryotic and eukaryotic cells

Cell dividing.

Image via Pixabay.

Between our self-awareness and the Internet, the power to wreck whole planets, opposable thumbs and all that jazz, we humans like to think of ourselves as the bee’s knees of life. All very impressive stuff, I’m sure everybody agrees, however, we’ve been quite favored. Perhaps the single biggest crutch our success rests upon is the sheer complexity and efficiency of our cells, all working together to keep us alive and smart enough to know that ‘cells’ are a thing. So what makes them so special, and are there any other kinds of cells wiggling around? Possibly making us sick?

The short answer is ‘the power of friendship’ and ‘yes’. Since that’s probably very confusing, let’s take a more in-depth look at the different types of cells out there.

The single most all-encompassing feature by which we classify cells is the way they order their internal structures, of which there are two overarching models: prokaryotic and eukaryotic. Both words are drawn from the ancient Greek root-word karyon, meaning ‘nut’ or ‘kernel’. The prefix pro, which means before, basically tells us that prokaryotes came ‘before kernels’ — because they sprang alife before the nucleus evolved. Their eukaryote counterparts, by contrast, are ‘true-kerneled’ organisms (the prefix eu means ‘true’), as they have nuclei.

Prokaryotes

E.coli bacteria.

E.coli bacteria.
Image credits Gerd Altmann.

Out of the two groups, prokaryotes are the oldest and arguably boast the simplest internal layout. Their most distinctive feature is that the bits which keep them going, each and every water-soluble cog in their chemical mechanisms, are all mixed together in the internal cytoplasm. There’s no nucleus — their genophore (folded DNA) looks like a ball of yarn that floats about, alongside proteins and metabolic by-products. Some prokaryote strains also employ a second level of information storage, in the form of plasmids: tiny rings of ‘extra’ genetic information that the cell picked up during its life. Prokaryotes lack complex internal layouts but are known to exhibit structures that can be viewed as early precursors of organelles, and they use smaller versions of ribosomes (the machines that make proteins.)

Prokaryotes’ cellular walls also stand out from their eukaryote counterparts. Living largely as single-cell entities, prokaryotes need to invest much more in defenses — both from predators and dangerous environmental factors. Their ‘walls’ rely on peptidoglycan or murein, which are much tougher than their counterparts’ fat-built walls. The rigid structure of peptidoglycan is specific only to prokaryotes. These membranes need to be tough, to maintain the overall shape of the lonely cells, and protect them against mechanical stress or damage from osmotic pressures and lysis (death by membrane rupture).

Prokaryotes are almost exclusively unicellular organisms and are primarily divided into the domains Archaea and Bacteria.

Eukaryotes

Human Cell.

Human cell seen through a Fluorescence Microscope during an experiment used to check whether the cell is able to fagocitate (eat) quantum dots. Membrane (red), nucleous (blue) and swallowed quantum dots (green).
Image credits Marc Vidal / Wikimedia.

Eukaryotes are more refined systems. The most glaring difference from their kernel-less counterparts is that most substances inside the cell are neatly packed into their own ‘box’. Chromosomes (DNA) are safely packed away in a nucleus (which has its own membrane), bits like mitochondria toil merrily away (behind their own membranes), metabolic products are stored in vacuoles (yep, membranes), they even have a Golgi apparatus, a membrane-producing stack of membranes — basically a cell-sized packaging plant. Eukaryotes can live as single-celled organisms but do so far less often than prokaryotes. They do, however, form the overwhelming majority of true multicellular organisms.

One other striking difference between the two is that eukaryotes are massive compared to prokaryotes. Valonia ventricosa, a species of algae known as the Sailor’s Eyeball which relatively common in tropical and subtropical waters, can grow up to 5.1 centimeters (2.0 in) in diameter — but it’s a single multinucleate cell. It’s definitely an outstanding species, but it’s by no means alone — Gromia Sphaerica, genus Acetabularia, and Caulerpa Taxifolia are a few other cells that grow to immense sizes. The neurons in your brain can grow to one whole meter in length if you measure the axon — and they’re also eukaryotic cells.

Those are extreme cases, but even typical eukaryotes generally grow to about 10-100 µm (micrometers) in diameter, while prokaryotes reach about 1-2 by 1-4 µm. Because they’re so much bigger, keep everything compartmentalized (which helps improve chemical reaction speeds massively) and employ specialized organelles, eukaryotes can specialize and perform much more complex functions than prokaryotes.

Clostridium vs Human Cell.

Example of prokaryote (Clostridium) in size comparison to eukaryote cells (human epithelial cells). The bar is 20 micrometers.
Image via Biophilia.

The sharp difference in complexity between prokaryotic and eukaryotic cells gave rise to a theory that the latter were formed, sometime in the distant past, by bunches of prokaryotes merging for mutual benefit. For example, mitochondria or chloroplasts likely once moved into another type of bacteria, pooling their resources and abilities to create a structured eukaryotic cell — the heaviest evidence in favor of this theory is that mitochondria still retain their own, inviolable DNA.

Such mergings could take place over and over again, as more prokaryotes joined up with already existing eukaryotes to form organized communities with a greater and greater complexity (and as such, greater and greater range of functions, which individual prokaryotes lack.)

Here’s an overview of the most important differences between the two types of cells:

 

Feature Prokaryote Eukaryote
General size 1-2µm by 1-4µm, or less. 10-100µm in diameter.
Organization Mostly unicellular. Some cyanobacteria may be multicellular. Mostly multicellular.
Nucleus Lack a true nucleus. Instead, they have a nucleoid. True nucleus, nuclear membrane.
Genetic material Generally have a single circular plasmid. No histones. Multiple linear chromosomes with histones.
DNA folding Around multiple proteins. Folded DNA is later supercoiled. Around histones.
Gene expression In groups called “operons”. Individually.
Division Budding (binary fission). Mitosis.
Genetic recombination (sexual reproduction) Limited to one-way transfer of DNA. No meiosis. Meiosis and fusion of gametes.
Nuclear wall permeability No nuclear wall. Selective permeability.
Cell skeleton Absent, some exceptions. Present.
Cell wall Chemically complex, usually including peptidoglycan (for bacteria). Chemically simple, usually includes cellulose or chitin.
Respiration Often strictly anaerobic. All aerobic, some also facultatively anaerobic.
Protein synthesis Transcription and translation occur simultaneously. Transcription in the nucleus, translation in the cytoplasm.
Metabolic pathways Wide range of variation. Glycolysis, electron transport chains, citric acid/Krebs cycle.
Chloroplasts Absent. Chlorophyll scattered throughout the cytoplasm. Present (in plants).
Can fix nitrogen? Some, yes. No.
Cellular cycle duration. 20-60 minutes. 12-24 hours.

 

The simple but hardy

P_vortex detail.

Detail of a Paenibacillus vortex bacteria colony.
Image via Wikimedia.

At first glance, it’s easy to assume that ‘simple’ and ‘primitive’ equate to ‘limited’, which would put prokaryotes just one step shy of ‘inferior’. But nature rarely stands up to such simple reductions. This apparent simplicity did wonders for all life on Earth in the long run — every organism today owes its existence to the first, humble prokaryotes. Testament to the efficiency of their design is one simple fact: prokaryotes, to this day, remain the most abundant and most stubbornly ubiquitous form of life on planet Earth.

It is in part their apparent primitiveness that led to this success. Greater simplicity means prokaryotes can multiply much more quickly and cheaply than eukaryotes. With faster reproduction comes a much more rapid rate of mutation, allowing for faster adaptation to new environments and faster development of diverse metabolic pathways. This adaptiveness, in particular, is super-charged by prokaryotes’ use of plasmids, allowing them to share genetic data between populations just as easily as you’d swap USB memory sticks with a classmate.

Simpler structures and smaller bulks also mean that prokaryotes find it easier to make ends meet, and they can take much more abuse than the posh eukaryotes before breaking down. Taken together, these two qualities allow prokaryotes to thrive, seemingly in bliss, in conditions that would kill other organisms faster than they could say “superior lifeform” — such as pools of strong acid or thermal vents on the ocean’s floor. In fact, more than 100 species of bacteria were found living in the toxic, radiation-drenched environment of the Hanford Nuclear Reservation, a place so extreme it was considered deadly to any and all forms of life. These things are so tough that NASA is legitimately concerned rovers will contaminate fricking Mars with Earthborn bacteria.

Strep. aureus.

Scanning electron micrograph of Strep. A (sore throat) bacteria.
Image credits Vincent A. Fischetti / The Rockefeller University.

The absence of organelles doesn’t seem to gimp prokaryotes too much, either. Lacking chloroplasts, mitochondria, or vacuoles, they simply perform all the tasks they need straight in their cytoplasm, possibly with the single-cell equivalent of a yolo hashtag. Sure, their processes usually don’t unfold as efficiently as those of a eukaryote, but what they gain is versatility. Versatility which seems to have won the envy (if not the hearts and minds) of multicellular organisms the world over: a small number of prokaryote bacteria are the only known organisms capable of breaking down the tri-atom nitrogen gas molecule and synthesizing nitrogen compounds which are vital to all multicellular organisms. It’s not uncommon for such bacteria to be offered bed and board at the roots of plants just for the nitrogen compounds they produce.

And these tiny prokaryotes have had more impact on your life than all human technology. Without them, there would be no agriculture. There would be no plants, at least not as we know them. Even if humans somehow evolved in their absence, we’d starve to death; even more so because animals of all kinds (including us) rely on populations of symbiotic bacteria (not a few bacteria — more in number than your own cells) to digest everything our bodies can’t, won’t, or just don’t know how to. Though we’d probably just choke and die first, since single-cells jump-started today’s oxygen-rich atmosphere.

In other words, not content with colonizing literally everywhere they could physically reach, even underwater volcanoes or outer space, prokaryotes have colonized virtually all higher organisms as well and are actively keeping them alive.

But you know, we’re totally the top species around. Totally.

The bright but fragile

Human stem cell.

Cryogenic scanning electron micrograph of a single human stem cell. It’s roughly 0.015 mm in diameter
Image credits Sílvia A Ferreira, Cristina Lopo, Eileen Gentleman / King’s College London.

While the achievements of prokaryotes can hardly be overestimated — from forming the first inklings of life to cyanobacteria producing the modern atmosphere that keeps us alive — eukaryotes also have a lot to boast about. It was, after all, eukaryotes working together that split the atom and made it to the moon — something their simpler brethren never managed on their own, but seem to have no problem freeloading on.

The thing that sets them apart most is that of complexity, both in form and of function. Eukaryotes are without a doubt more complex mechanisms. The goings-on of their internal processes are neatly distributed throughout separate rooms, making the reactions much faster and more efficient since different compounds don’t get in each other’s way (at the level of a cell, chemicals aren’t imperceptibly tiny, they’re beams and cranes, engines and thick plates). For example, animal cells contain mitochondria, while plants contain chloroplasts, both of which can churn out energy on a level prokaryotes can only dream of.

Nowhere is this organization more relevant than in the case of DNA — behind the walls of their nucleus, eukaryotes’ genetic material is kept as safe as possible. Reading and copying of DNA are much faster here than in a prokaryote’s floating mess of a cytoplasm. The information can be better guarded against happenstance chemical or physical alterations (mutations) because of the safety the nucleus provides, and due to better folding and storing of data in the form of chromosomes. All this complexity also means eukaryotes carry much more genetic information. Your average prokaryote only sports about 0.001% of the genetic material in a eukaryote.

White cell chasing bacteria.

White cell (eukaryote) chasing bacteria (prokaryote) with incredible agility despite their relative sizes.

Eukaryotes are also simply better at getting around, as counterintuitive as that may be. It all, again, comes down to internal structures. Prokaryotes generally use protein flagella (wiggly tails) to move around, but they have poor control over where they’re actually going — they can go forward, or into a tumbling reverse spin. Despite living their life in comfort among their peers and not generally wandering about, eukaryotes possess internal filaments which serve to maintain their shape. These filaments can constrict to change the cell’s shape, allowing them to perform very complex movements with a high degree of control, both inside and outside of the cell.

Then there’s a final level of complexity. Eukaryotes work together to form organisms, whereas prokaryotes rarely do. If you’re not really sure why one is better than the other, well, even ‘being unsure’ is only possible because you’re a bunch of cells working together, and some of them are confused.

Working together also bred increasing specialization in eukaryotes. Sponges, some of the earliest multicell life out there, were basically a handful of eukaryotes all bunched together for safety in colonies where everyone did the same things. Everybody digested food, everyone pooped in the same place where they ate. Life’s classy like that. Over time, however, evolution has fashioned incredible systems out of these cells, from brains that can comprehend quantum physics to animals that weighed 65 tons.

All that is possible because of specialization: some cells get nutrients out of food, others tell everyone what to do, others keep everyone away from things that want to eat the lot. Arguably, this has also created eukaryotes’ greatest Achilles’ heel. In a sense, cells in multicell organisms are domesticated — they’ve grown to rely on each other to such an extent that they can’t survive alone any longer. They’re extremely efficient, but they need fine-tuned conditions to work in. They’re incredibly capable as a whole, and hopelessly out of their depth on their own.

Liver cells.

A small piece of human liver grafted into a mouse with a damaged liver.
Image credits Chelsea Fortin, Kelly Stevens, and Sangeeta Bhatia / Koch Institute, © MIT.

It is largely because of this interdependence that prokaryotes are one of the biggest threats to eukaryotic life. Bacteria don’t want to ‘make you sick’, they just want to eat and make babies. Problem is, when they eat bits of you and make babies inside of you, this ruins all the soft, comfy conditions your eukaryotes need to live. And as we’ve seen, prokaryotes are the burly tanks of cellular life, while your eukaryotes are huge and brilliant, but kinda wimpy, squishy things.

But working together, eukaryotes have developed antibiotics to help tilt the battlefield in their favor (for a while). And working together, these cells have literally reached for the stars. Not bad for some wimpy, squishy things.


So what do you think? Will sophisticated cells working together prove to be evolution’s greatest achievement, or will the meek (prokaryote) finally inherit the Earth when we go the way of the dinosaurs? Let us know in the comments below.

rejuvenation

New therapy rejuvenates old cells in the lab, which now behave like young cells

A novel method developed at the University of Exeter rejuvenates old cells cultured in the lab, causing them to behave more like young cells. It took only a couple of hours after the treatment was applied to the old cells for these to start dividing and growing larger telomers. The technique could lead to a new class of therapies meant to help people age not only longer but healthier, too.

rejuvenation

Credit: Pixabay.

As we age, the cells in the body quietly but surely enter senescence, meaning they cease to divide. These cells are still alive, it’s just that they stop functioning properly. For instance, a class of genes called splicing factors are progressively switched off as humans age.

Splicing factors are crucial proteins that help gene perform their full range of functions. A single gene can code multiple instructions for the body, such as whether or not to grow new blood vessels, and the splicing factors are the decision makers that choose which message takes priority. Because splicing factors become increasingly inefficient with age, the body ends up losing its ability to respond properly to the many challenges in the environment.

Senescent cells can be found in copious amounts in the organs of the elderly. They’re one of the main reasons why most people over age 85 have experienced some sort of chronic illness. Switched off splicing factors make people more vulnerable to cancer stroke, and heart disease as they age.

Led by Professor Lorna Harries, researchers at the University of Exeter experimented with resveratrol analogs on old cells in the lab. These chemicals are based on a substance naturally found in red wine, dark chocolate, red grapes, and blueberries.

Credit: BMC Cell Biology.

Credit: BMC Cell Biology.

Strikingly, within hours of coming into contact with the compounds, the splicing factors in the cells switched back on. The cells showed signs of rejuvenation as they started dividing, essentially behaving like young cells. What’s more, the cells’ telomeres — the caps on the ends of the chromosomes that shorten as we age —  are now longer, as they are in young cells

“At present, the precise mechanisms behind these observations are unclear, but may involve both the restoration of a more ‘youthful’ pattern of alternative splicing, and also effects of specific splicing factors on telomere maintenance,” the authors conclud in their paper.

“This demonstrates that when you treat old cells with molecules that restore the levels of the splicing factors, the cells regain some features of youth,” Harries said.

The findings published in the journal BMC Cell Biology could potentially lead to therapies that help people age healthier, with less risk of developing chronic disease and by delaying the usual degenerating effects of old age.

“When I saw some of the cells in the culture dish rejuvenating I couldn’t believe it. These old cells were looking like young cells. It was like magic,” said co-author Eva Latorre, Research Associate at the University of Exeter. “I repeated the experiments several times and in each case the cells rejuvenated. I am very excited by the implications and potential for this research.”