Cell biology

From Elizabeth Pennisi at Science: The evolutionary histories of some groups of organisms record repeated transitions from single-celled to multicellular forms, suggesting the hurdles could not have been so high. Genetic comparisons between simple multicellular organisms and their single-celled relatives have revealed that much of the molecular equipment needed for cells to band together and coordinate their activities may have been in place well before multicellularity evolved. And clever experiments have shown that in the test tube, single-celled life can evolve the beginnings of multicellularity in just a few hundred generations—an evolutionary instant. Evolutionary biologists still debate what drove simple aggregates of cells to become more and more complex, leading to the wondrous diversity of life today. But embarking on Read More ›

Such acell might shed some light on the origin of life, researchers hope. From Suzan Mazur at Oscillations: Not to be outdone by Dutch, German and other Europeans now officially dabbling in synthetic cell research, America’s National Science Foundation has thrown its hat into the ring on funding synthetic cell development, per its April 18, 2018 letter to colleagues inviting proposals on the design and engineering of synthetic cells and cell components ($100K for relevant conferences, $300K re multicomponent subsystems, and up to $1M for research on the “pseudo-cell”). In May, following its call for proposals, NSF co-sponsored a synthetic and artificial cells roadmap meeting in Alexandria, Virginia with a handful of scientists already working in the field presenting and Read More ›

From Denyse O’Leary at Salvo: Minority Reporter: A Finnish Bioengineer Touches the Third Rail Randomness and chaos are much easier to market today than order, meaning, and purpose. The songs write themselves. Serious scientists, therefore, can find themselves in conflict with a view that is not so much an argument as an attitude to life, not so much a marshalling of evidence as a demand that posturing overrule evidence. Case in point: Matti Leisola, a gifted Finnish bioengineer, started out as a good Darwinist. But he could not avoid the massive pushback from the evidence of design he . . . More. Yes, it’s mostly paywalled. It describes the situation of a scientist who thinks that nature shows evidence of Read More ›

From molecular biologist Mike Klymkowsky at The Scientist There is a pernicious temptation in science to speak authoritatively about topics that are beyond scientific exploration and certainty. This has led some theoretical physicists to advocate for a “post-empirical” form of science. That is the idea that theories need not be judged on their ability to make new and testable predictions about the observable universe, in some cases, the absence of a plausible alternative is sufficient. … Klymkowsky is certain that there was a single Last Universal Common Ancestor (LUCA)* but before that? But what came before and the exact steps leading to LUCA are unknowable. Moreover, the billions of years that have elapsed since LUCA’s origin and the active nature Read More ›

Mechanobiology is an engineer’s vision of the cell: How do forces and mechanisms in cells and tissues contribute to cell development, differentiation, function, and deterioration (disease). From Suzan Mazur at Oscillations: The mechanobiology field actually goes by assorted names, among them: soft matter, the new condensed matter physics, morphomechanics, morphometrics, biomechanics, biophysics, mathematical biology (partial list), and importantly integrates life across the board: animals, plants, fungi, microbes—which has to include viruses. It also encompasses materials science. So you can put active matter under the mechanobiology umbrella (but without Lee Cronin’s “Alien chemist“). When I say mechanobiology is all the rage, I’m not simply referring to lab research and scientific conferences on the subject, although they are, of course, central. But Read More ›

From ScienceDaily: Researchers at the Stowers Institute for Medical Research have captured the one cell that is capable of regenerating an entire organism. For over a century, scientists have witnessed the effects of this cellular marvel, which enables creatures such as the planarian flatworm to perform death-defying feats like regrowing a severed head. But until recently, they lacked the tools necessary to target and track this cell, so they could watch it in action and discover its secrets. … “This is the first time that an adult pluripotent stem cell has been isolated prospectively,” says Alejandro Sánchez Alvarado, Ph.D., an investigator at the Stowers Institute and Howard Hughes Medical Institute and senior author of the study. “Our finding essentially says Read More ›

From Jonathan Wells at ENST, looking at a variety of systems, including the bioelectric code: Regional differences in cells and embryos can be specified in other ways besides localization of RNAs in the cortex. Two of those ways have been studied in great detail: the “sugar code” and the “bioelectric code.” Most proteins in living cells — including those in membranes — are chemically bonded to carbohydrates called “glycans” (from the Greek word for “sweet”). The nucleotides in DNA are linked together end-to-end in a linear molecule, so DNA sequence information is one-dimensional. In living cells, the subunits in proteins (with a few exceptions) are also linked in a linear chain. But glycans can be linked together in complex three-dimensional Read More ›

From Sarah Zhang at the Atlantic: As you read this article, the cells in your body are dividing and the DNA in them is being copied, letter by letter. So long is the human genome—more than 3 billion letters—that even an astonishingly low error rate of one in many million letters could amount to 10 new mutations every time a cell divides. Oh, perhaps you’re also catching some sun (ultraviolet rays) while you read this, or enjoying a beer (alcohol), or have recently been high in the atmosphere on an airplane (cosmic rays). Congratulations, you’ve given yourself even more mutations. In a typical day, scientists estimate, the 37 trillion cells in your body will accumulate trillions of new mutations.More. We Read More ›

From Eugene Koonin at Immunoconcept: Abstract: The CRISPR-Cas systems of bacterial and archaeal adaptive immunity have become a household name among biologists and even the general public thanks to the unprecedented success of the new generation of genome editing tools utilizing Cas proteins. However, the fundamental biological features of CRISPR-Cas are of no lesser interest and have major impacts on our understanding of the evolution of antivirus defense, host-parasite coevolution, self vs non-self discrimination and mechanisms of adaptation. CRISPR-Cas systems present the best known case in point for Lamarckian evolution, i.e. generation of heritable, adaptive genomic changes in response to encounters with external factors, in this case, foreign nucleic acids. CRISPR-Cas systems employ multiple mechanisms of self vs non-self discrimination Read More ›

The eukaryote smashes and rearranges its genome. Our results show that a great diversity of scrambled gene maps are present in the germline genome of O. trifallax. The presence of such highly nested architectures was a surprise and suggests that layers upon layers of MDS and gene translocations constantly alter the genome, while the detection of highly scrambled patterns reveals architectures that transcend simple twists and turns of the DNA. We present new metrics of topological genome complexity, that go beyond the linear nature of eukaryotic chromosomes and consider their deeply structured and layered history. While several models of genome rearrangement have been reported, the unprecedented levels of rearrangements in this system necessitate additional descriptive and mathematical tools, some of Read More ›

From ScienceDaily: Queensland University of Technology (QUT) researcher Dr Robyn Araujo has developed new mathematics to solve a longstanding mystery of how the incredibly complex biological networks within cells can adapt and reset themselves after exposure to a new stimulus. … “Proteins form unfathomably complex networks of chemical reactions that allow cells to communicate and to ‘think’ — essentially giving the cell a ‘cognitive’ ability, or a ‘brain’,” she said. “It has been a longstanding mystery in science how this cellular ‘brain’ works. “We could never hope to measure the full complexity of cellular networks — the networks are simply too large and interconnected and their component proteins are too variable. “But mathematics provides a tool that allows us to Read More ›

From Peter Dockrill at Science Alert: For the first time, scientists have identified the existence of a new DNA structure never before seen in living cells. The discovery of what’s described as a ‘twisted knot’ of DNA in living cells confirms our complex genetic code is crafted with more intricate symmetry than just the double helix structure everybody associates with DNA – and the forms these molecular variants take affect how our biology functions. “When most of us think of DNA, we think of the double helix,” says antibody therapeutics researcher Daniel Christ from the Garvan Institute of Medical Research in Australia. “This new research reminds us that totally different DNA structures exist – and could well be important for Read More ›

From James Gallagher at BBC: Prof Rob Knight, from University of California San Diego, told the BBC: “You’re more microbe than you are human.” Originally it was thought our cells were outnumbered 10 to one. “That’s been refined much closer to one-to-one, so the current estimate is you’re about 43% human if you’re counting up all the cells,” he says.More. Well, if that’s true, human life is not at all what the lectern splinterers claim. See also: If viruses can evolve in parallel in related species… ? and Science fictions series 4: Naturalism and the human mind

From ScienceDaily: Scientists from the universities of Exeter and Cambridge compared viruses that evolved in different species and found “parallel genetic changes” were more likely if two host species were closely related. … “This may explain in part why host shifts tend to occur between related species. However, we sometimes see the same mutations occurring in distantly related host species, and this may help explain why viruses may sometimes jump between distantly related host species. “At present we know very little about how viruses shift from one host species to another, so research like this is important if we want to understand and ultimately predict emerging viral diseases.” Paper. (public access) – Ben Longdon, Jonathan P Day, Joel M Alves, Read More ›

We told you so! Four horsemen. No waiting. From Brian Miller at ENST: One of the most significant projects for the intelligent design movement was Douglas Axe’s research testing the rarity of protein folds. Axe’s method represented the most accurate approach for addressing the problem to date, but his was actually one in a line of studies which concluded that amino acid sequences forming the stable proteins found in nature are exceedingly uncommon. As a consequence, most proteins seen in life could never have originated via random mutations and selection. One of the early online critics of Axe’s work was Arthur Hunt, who wrote a lengthy critique at the Darwinian advocacy site Panda’s Thumb. His area of expertise is not Read More ›