Cell biology

Careful study showed that this was not the result of contamination: In a surprise to scientists, cyanobacteria have been found thriving nearly 2,000 feet below the strange landscape, where sunlight, water, and nutrients are scarce. Researchers previously thought these microbes could survive only while basking in the sun’s rays, although they are otherwise a versatile bunch; researchers have found them alive nearly everywhere on Earth. … Control samples helped the team determine that the microbes did not come from contamination due to the drilling fluid nor from processing in the lab. And the cyanobacteria were not found in random locations, as you might expect if the samples had been doused in contaminated liquid. Instead, they were congregating along the fractures Read More ›

Matti Leisola, author of Heretic: One Scientist’s Journey from Darwin to Design, offers some thoughts on the recent announcement: I am an enzyme bioengineer, so I greeted with enthusiasm Wednesday’s announcement… that part of the 2018 Nobel Prize in Chemistry went to a fellow enzyme bioengineer. She is Frances H. Arnold, a professor of chemical engineering at Caltech. … There is one point of confusion in descriptions of this year’s prize winners. It’s the talk of “directed evolution.” The Nobel Prize organization itself has encouraged such talk. If it is “directed” by researchers engineering the rates for specific purposes, sorting according to specific goals, it isn’t “evolution” in the usual schoolbook sense at all. It is more like plant breeding. Read More ›

Sloan Kettering molecular biologist argues that this may not be semantics. What if that’s what they are actually doing, in effect? One wonders, how would it affect cancer treatment? Abstract: Living organisms must maintain proper regulation including defense and healing. Life-threatening problems may be caused by pathogens or an organism’s own cells’ deficiency or hyperactivity, in cancer or auto-immunity. Life evolved solutions to these problems that can be conceptualized through the lens of information security, which is a well-developed field in computer science. Here I argue that taking an information security view of cell biology is not merely semantics, but useful to explain features of cell signaling and regulation. It also offers a conduit for cross-fertilization of advanced ideas from computer Read More ›

At one time, the cell membrane was thought of as something like a building block made of lipids. Suzan Mazur interviews Swedish physical chemist Tommy Nylander about the study of living cells through neutron scattering (to avoid contamination, the Swedes do the studies without nuclear power or mercury) at Oscillations: Tommy Nylander:I’m very interested in different structures that can occur in living cells. In particular, structures generated by lipids, or fats, if you want. Previously lipids were considered as only a building block with no or very minute function. Merely a support. Suzan Mazur: Cell membranes are made of lipids. Tommy Nylander: Yes. Today it’s realized that lipids can perform various functions that can be very important for cell maintenance Read More ›

Readers will remember science writer David Quammen’s new book, The Tangled Tree:A Radical New History of Life, a biography of Carl Woese, who first identified the Archaea (and doubted Darwinism). They will also doubtless remember Darwinian evolutionary biologist Jerry Coyne, who does not life Tangled Tree, and… Well, he still doesn’t like it and has been holding forth of late: Most of the publicity about the book—to be sure, publicity pushed by Quammen himself—centers on HGT. It is, we’re told, something that radically overturns Darwin’s view of the “tree of life” and of evolution, and even revises our own view of “what it means to be human” (after all, we’re also told, a substantial part of our genome is dead, Read More ›

Neutrons can be used to probe living tissues without damaging them (neutron scattering). Suzan Mazur interviews biophysicist John Katsaras, whose specialty is cell membranes, at Oscillations on their implications for studying the origin and development of life forms. Among the fascinating details, Suzan Mazur: Your membranes research revealed that lipids gathered with others of their type. John Katsaras: Right. The cell makes thousands of different types of lipids. In the plasma membrane, which is the outer membrane of the cell, there are hundreds or, maybe thousands of different lipids. The question is, why does the cell expend so much energy to make all of these different lipids. You could say, well, maybe they have all different physical properties.. As a Read More ›

At Rutgers: How did life arise on Earth? Rutgers researchers have found among the first and perhaps only hard evidence that simple protein catalysts – essential for cells, the building blocks of life, to function – may have existed when life began. Their study of a primordial peptide, or short protein, is published in the Journal of the American Chemical Society. In the late 1980s and early 1990s, the chemist Günter Wächtershäuser postulated that life began on iron- and sulfur-containing rocks in the ocean. Wächtershäuser and others predicted that short peptides would have bound metals and served as catalysts of life-producing chemistry, according to study co-author Vikas Nanda, an associate professor at Rutgers’ Robert Wood Johnson Medical School. Human DNA Read More ›

Surviving the Late Heavy Bombardment: We find that the “last universal common ancestor” – a hypothetical very early single cell from which all life on Earth descended – existed prior to the “late heavy bombardment”. This was a period of intense meteor bombardment sustained by our planet about 3.9 billion years ago. This is significantly earlier than the currently accepted oldest fossil evidence would suggest (estimating 3.5-3.8 billion years ago). The oldest confirmed fossils are from about 3.4 billion years ago, while the oldest potential fossils have been found on Greenland and date back to about 3.8 billion years ago. There’s also a suggestion that carbon found in a 4.1 billion-year-old mineral called zircon could be biological in nature. However, Read More ›

Philip Cunningham writes to note for us such moments in the literature: Abstract: (open access) Why life persists at the edge of chaos is a question at the very heart of evolution. Here we show that molecules taking part in biochemical processes from small molecules to proteins are critical quantum mechanically. Electronic Hamiltonians of biomolecules are tuned exactly to the critical point of the metal-insulator transition separating the Anderson localized insulator phase from the conducting disordered metal phase. Using tools from Random Matrix Theory we confirm that the energy level statistics of these biomolecules show the universal transitional distribution of the metal-insulator critical point and the wave functions are multifractals in accordance with the theory of Anderson transitions. The findings Read More ›

The world-class symposium features several controversies long the lines of 1) Should we build a synthetic cell and 2) Aren’t we really doing that under another name anyway? Suzan Mazur reports at her blog, Oscillations: The late Carl Woese, who was awarded the Leeuwenhoek Medal by the Royal Netherlands Academy of Arts and Sciences (1992), opposed the idea of making a synthetic cell, telling me in a 2012 interview weeks before he died that he thought the push for a synthetic cell was all about “Power” and scientists “thinking they’re God.” … The Dutch conference promo never actually defines life. It does, however, address why the country has decided to build a synthetic cell. It repeats the mantra that the Read More ›

From Susan Milius at ScienceNews: In the final frenzy of reproduction and death, social amoebas secrete proteins that help preserve a starter kit of food for its offspring. Dictyostelium discoideum, a type of slime mold in soil, eats bacteria. Some wild forms of this species essentially farm the microbes, passing them along in spore cases that give the next generation of amoebas the beginnings of a fine local patch of prey. Tests find that the trick to keeping the parental immune system from killing this starter crop of bacteria is a surge of proteins called lectins, researchers say in the July 27 Science.More. Slime molds are known for a sophistication that approaches that of an insect colony: Apparent intelligence can Read More ›

From ScienceDaily: A concept known as ‘percolation’ is helping microbiologists explain how communities of bacteria can effectively relay signals across long distances. Once regarded as a simple cluster of microorganisms, communities of bacteria have been found to employ a strategy we use to brew coffee and extract oil from the sea. Percolation helps the microscopic community thrive and survive threats, such as chemical attacks from antibiotics. … Biofilm communities inhabit locations all around us, from soil to drain pipes to the surface of our teeth. Cells at the edge of these communities tend to grow more robustly than their interior counterparts because they have access to more nutrients. To keep this edge growth in check and ensure the entire community Read More ›

From ScienceDaily: Researchers have developed new techniques to track the mobilization of jumping genes. They found that during a particular period of egg development, a group of jumping-genes called retrotransposons hijacks special cells called nurse cells that nurture the developing eggs. These jumping genes use nurse cells to produce invasive material (copies of themselves called virus-like particles) that move into a nearby egg and then mobilize into the egg’s DNA driving evolution, and causing disease. … Carnegie co-author Zhao Zhang explained: “We were very surprised that the these jumping genes barely moved in stem cells that produce developing egg cells, possibly because the stem cells would only have two copies of the genome for these jumping genes to use. Instead, Read More ›

From science writer Suzan Mazur, at Oscillations, interviewing Bogdan Dragnea, who studies the physical structure of viruses via spectrosopy: Suzan Mazur: Do you consider viruses live organisms since viruses can recognize their targets, attach, and infect their hosts—most viruses using a tail spike and needle [see following Parent lab image]—and as you’ve noted, they can “drive large-scale phenomena across the entire biosphere”? Bogdan Dragnea: No, I don’t. I will stick with the definition that requires for a living organism to reproduce and produce mechanical work in a thermodynamic cycle. If it could do that, then I would say it’s alive. But the virus cannot do mechanical work as part of a cyclic transformation. That is because they do not have Read More ›

From Josh Bloom at American Council for Science and Health: I recently wrote about three of the deadly neurotoxins being produced by cyanobacteria (aka blue-green algae) during an ongoing algae bloom in South Florida (See Florida’s Deadly Algae Bloom – Why Is It So Dangerous?). The toxins range from structurally simple and easy for organic chemists to synthesize in the lab to moderately complex and not simple at all. But there are numerous examples of plants, marine organisms, and bacteria that easily biosynthesize molecules that are so complex and difficult to make synthetically that chemistry grad students and post-docs who were given the unenviable task of doing so are probably still waking up in cold sweats thinking about what they Read More ›