Posts Tagged ‘Life’
“Without debatement further, more or less, / He should the bearers put to sudden death, / Not shriving time allow’d.”*…
“Cell suicide” is inherently self-destructive, and yet it’s an essential and productive process in complex organisms. How did cells evolve a process to end their own lives? As Veronique Greenwood reports, recent research suggests it first arose, first arose billions of years ago… but why?…
It can be hard to tell, at first, when a cell is on the verge of self-destruction.
It appears to be going about its usual business, transcribing genes and making proteins. The powerhouse organelles called mitochondria are dutifully churning out energy. But then a mitochondrion receives a signal, and its typically placid proteins join forces to form a death machine.
They slice through the cell with breathtaking thoroughness. In a matter of hours, all that the cell had built lies in ruins. A few bubbles of membrane are all that remains.
“It’s really amazing how fast, how organized it is,” said Aurora Nedelcu, an evolutionary biologist at the University of New Brunswick who has studied the process in algae.
Apoptosis, as this process is known, seems as unlikely as it is violent. And yet some cells undergo this devastating but predictable series of steps to kill themselves on purpose. When biologists first observed it, they were shocked to find self-induced death among living, striving organisms. And although it turned out that apoptosis is a vital creative force for many multicellular creatures, to a given cell it is utterly ruinous. How could a behavior that results in a cell’s sudden death evolve, let alone persist?…
The story in full: “Cellular Self-Destruction May Be Ancient. But Why?“, from @vero_greenwood in @QuantaMagazine.
* Shakespeare, Hamlet (Act 5, Scene 2)
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As we appreciate apoptosis, we might send healthy birthday greetings to Lillian Wald; she was born on this date in 1867. A nurse, humanitarian, political reformer, and author, she was instrumental in establishing a nationwide system of nurses in public schools. Known as “the Angel of Henry Street” (for her founding and running of the Henry Street Settlement in New York City), she directed the Henry Street Visiting Nurse Service, while at the same time tirelessly opposing political and social corruption. She helped initiate the revision of child labor laws, improved housing conditions in tenement districts, drove the enactment of pure food laws, championed and improved education for the mentally handicapped, and led the passage of enlightened immigration regulations.
“If you want to understand today you have to search yesterday”*…
… and for your searching pleasure here are all of our yesterdays, in an animation scrolling by at 1.5 million years per second…
Earth is 4.5 billion years old – which is approximately the same amount of time it took us to create this video. We’ve scaled the complete timeline of our Earth’s life into our first animated movie!… Hop on a musical train ride and experience how long a billion years really is. It’s the perfect background for your next party, a great way to take a break from studying, or a fascinating companion while you’re on the go…
From German animation house Kurzgesagt (“in a nutshell”)…
Posters here.
* Pearl Buck
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As we trace our steps, we might recall that it was on this date in 1913 that Gulf Refining Company opened the first “drive-in filling station” in Pittsburgh. It was the first architect-designed station and the first to distribute free road maps; it also offered tube and tire installation, free water and air, and crankcase services.
“The only reason for time is so that everything doesn’t happen at once”*…
Our lives are spread across range of ways that we spend our time. A newly-published study tracks time-use around the world…
How do you spend each day? Researchers sought answers to that basic question from people of various ages living around the world. They report that on an average day, people spend more than a third of their time focused on matters of health, happiness and keeping up appearances.
“We found that the single largest chunk of time is really focused on humans ourselves, a little more than 9 hours,” explained study author Eric Galbraith, of McGill University in Montreal, Canada. “Most of this—about 6.5 hours—is doing things that we enjoy, like hanging out, watching TV, socializing and doing sports,” he said. Reading and gaming also fall within this rubric.
The other 2.5 hours (out of the 9) are spent on hygiene, grooming and taking care of our own health and that of our kids, said Galbraith, a professor in the department of earth and planetary sciences.
Sleep and bedrest occupy the next largest chunk of time: more than 9 hours on average. That sounds like a lot of shut-eye, but Galbraith stressed this number reflects the average across the full age span, so it includes kids who might sleep up to 11 hours a day. “It also includes time in bed and not sleeping, which can be as much as one hour per day,” he said…
The remaining minutes? They seem to go toward getting organized, moving about or producing, creating and maintaining things and spaces…
For more findings and background on the methodology: “Sleep, cleaning, fun: Research reveals the average human’s day worldwide,” in @physorg_com.
* Albert Einstein
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As we contemplate chronology, we might recall that it was on this date in 2011 that the Swedish game design house Mojang Studios released the first full version of Minecraft. A sandbox game created by Markus “Notch” Persson, it has become the best-selling video game in history, with over 300 million copies sold– and countless hours consumed…
“There are more things in heaven and Earth, Horatio, than are dreamt of in your philosophy”*…
And some of them were recently found in the woods near Boston…
Researchers have unearthed a trove of wonders in the soil of a Massachusetts forest: an assortment of giant viruses unlike anything scientists had ever seen. The find suggests this group of relatively massive parasites has an even greater ecological diversity and evolutionary importance than researchers knew.
Giant viruses can exceed 2 micrometers in diameter, on par with some bacteria. They can also harbor immense genomes, which reach 2.5 megabases—larger than the genomes of far more complex organisms. Between the discovery of these impressively sized viruses in algae and the culturing of amoeba-infecting Mimiviruses, most of the research on the group has focused on viruses that inhabit freshwater environments. But DNA sequencing has long indicated that giant viruses are diverse and abundant elsewhere, too—especially in sediments and soils, which are estimated to host some 97% of all the viral particles on Earth. Indeed, genomic sequencing of the soils of Harvard Forest—a roughly 16-square-kilometer area west of Boston—indicated the presence of numerous, novel giant viruses.
Now, electron microscopy has allowed scientists to see what others had only sequenced. The diversity of forms was astounding, they report in a bioRxiv preprint. Not only did the researchers see the 20-sided icosahedral shapes they expected, they spotted ones with myriad modifications—tails, altered points, and multilayered or channeled structures abounded. There were even viruses with long tubular appendages, which the team dubbed “Gorgon” morphology [photo above]. Furthermore, many of these putative viral particles were coated with almost hairlike projections, which varied in length, thickness, density, and shape.
The findings suggest virologists have much to discover about how giant viruses interact with their host cells. That likely means the ecological roles these viruses play in soils—and elsewhere they’re found—are woefully underappreciated…
Microbes come in a variety of shapes, hinting at undiscovered ecological diversity: “Alien-looking viruses discovered in Massachusetts forest,” in @ScienceMagazine.
* Shakespeare, Hamlet
As we marvel at multifariousness (and note that viruses, while generally considered to be non-living and thus not considered microorganisms, are colloquially lumped in with microbes), we might spare a thought for Sidney Walter Fox; he died on this date in 1998. A biochemist, he was responsible for a series of discoveries about the origin of life. Fox believed in the process of abiogenesis, by which life spontaneously organized itself from the colloquially known “primordial soup,” poolings of various simple organic molecules that existed during the time before life on Earth. In his experiments (which possessed, he believed, conditions like those of primordial Earth), he demonstrated that it is possible to create protein-like structures from inorganic molecules and thermal energy. Dr. Fox went on to create microspheres that he said closely resembled bacterial cells and concluded that they could be similar to the earliest forms of life or protocells.
“Nature is full for us of seeming inconsistencies and glad surprises”*…
George Musser talks with biologist Michael Levin about his practice of uncovering the incredible, latent abilities of living things…
Michael Levin, a developmental biologist at Tufts University, has a knack for taking an unassuming organism and showing it’s capable of the darnedest things. He and his team once extracted skin cells from a frog embryo and cultivated them on their own. With no other cell types around, they were not “bullied,” as he put it, into forming skin tissue. Instead, they reassembled into a new organism of sorts, a “xenobot,” a coinage based on the Latin name of the frog species, Xenopus laevis. It zipped around like a paramecium in pond water. Sometimes it swept up loose skin cells and piled them until they formed their own xenobot—a type of self-replication. For Levin, it demonstrated how all living things have latent abilities. Having evolved to do one thing, they might do something completely different under the right circumstances.
Not long ago I met Levin at a workshop on science, technology, and Buddhism in Kathmandu. He hates flying but said this event was worth it. Even without the backdrop of the Himalayas, his scientific talk was one of the most captivating I’ve ever heard. Every slide introduced some bizarre new experiment. Butterflies retain memories from when they were caterpillars, even though their brains turned to mush in the chrysalis. Cut off the head and tail of a planarian, or flatworm, and it can grow two new heads; if you amputate again, the worm will regrow both heads. Levin argues the worm stores the new shape in its body as an electrical pattern. In fact, he thinks electrical signaling is pervasive in nature; it is not limited to neurons. Recently, Levin and colleagues found that some diseases might be cured by retraining the gene and protein networks as one might train a neural network. But when I sat down to talk to the audacious biologist on the hotel patio, I mostly wanted to hear about slime mold…
Read on for a fascinating conversation: “The Biologist Blowing Our Minds,” @drmichaellevin and @gmusser in @NautilusMag.
* Margaret E. Barber
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As we’re amazed, we might send tidy birthday greetings to Irwin Rose; he was born on this date in 1926. A biologist and biochemist, he shared the 2004 Nobel Prize in Chemistry for the discovery of ubiquitin-mediated protein degradation.
Ubiquitin is a small protein molecule that attaches to other proteins, tagging them for removal, which are thus recognized by the cell’s proteasomes. These structures are the cell’s waste-disposal units, allowing the proteins to be broken down into tiny pieces for reuse; this ubiquitin-mediated process cleans up unwanted proteins resulting during cell division, and performs quality control on newly synthesized proteins… which matters, as faulty protein-breakdown processes lead to such conditions as cystic fibrosis, several neurodegenerative diseases, and certain types of cancer.
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