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Artist stuffs Wikipedia into apple DNA to create real trees of knowledgeIf DNA is code, and code can be art, then DNA can be art... right? Harvard artist in residence Joe Davis certainly thinks so. He's working on a project, Malus Ecclesia, that will insert Wikipedia entries into the non-essential genetic strands of apples. The effort will translate English Wikipedia articles to DNA's four nucleotide letters (A, C, G and T) and use bacteria to insert the resulting text into saplings. When the saplings are grafted on to apple stock and grow up, they'll bear fruit with that genetic data (and therefore the articles) intact, producing very real trees of knowledge.Davis' living artwork won't be as revelatory as the biblical tree, though. The bacteria can only hold a few thousand words, while Wikipedia has roughly 2.5 billion; it will take a large grove to hold the entire database. You probably also won't get to take a bite, since there are tough US regulations on genetically modified plants. Even so, it should be an impressive feat if everything goes as planned -- and it could serve as a proof of concept for other, more practical uses of genes as storage systems.
How the Heck Did Black Widow Spider DNA Get Inside a Virus?Scientists have found some toxic DNA lurking inside a virus that infects bacteria. In addition to its own genes, the virus holds a gene for black widow spider venom and DNA from other animals, the researchers found. The findings suggest that either the virus snagged this foreign genetic material or that these other animals have stolen DNA from the virus, the researchers said.Future research could find that such swapping across domains of life, from the most complex to the most ancient, is more common than previously thought, scientists say.Stealing DNAViruses infect all three domains of the tree of life. The most complex forms of life on Earth — including animals, plants and fungi — belong to the domain Eukaryota, whose cells possess nuclei. The other two domains include the prokaryotes, the earliest forms of life — single-celled microbes that lack nuclei. There are two prokaryotic domains — the familiar Bacteria, as well as Archaea, which includes microorganisms that thrive in harsh environments such as hot springs and underground petroleum deposits. Each virus infects just one domain of life. For instance, bacteriophages, which are viruses that attack bacteria, cannot infect eukaryotes, or cells with nuclei. In part due to this specificity, scientists have explored using these so-called "phages" in therapies to kill antibiotic-resistant bacteria.Previous research found that viruses can pick up genes from their hosts, using this "stolen" DNA to evade and manipulate their victims. Because each virus infects only one domain of life, scientists would not expect a phage to possess animal DNA, for example.Viruses that infect bacteriaHowever, previous research found that a number of bacteria do live in eukaryotes — for instance, harmful parasites or mostly helpful symbionts such as E. coli that live in hosts such as humans and other animals. This idea raised the possibility that phages that infect such bacteria might regularly be exposed to DNA from the eukaryotic hosts of these bacteria.In the new study, scientists investigated the phage WO, which infects the bacterium Wolbachia. This bacterium infests an estimated 40 percent of the most species-rich group of animals worldwide, the arthropods, which include insects, spiders and crustaceans."Wolbachia are among the most widespread bacterial infections on the planet," said study co-author Seth Bordenstein, a microbiologist at Vanderbilt University in Nashville, Tennessee.The researchers found that this phage's genome (or the complete set of genes within each cell of an organism) contains a number of genes similar to some seen in eukaryotes. "This is the first time, to the best of my knowledge, that animal genes were found in bacteriophages," Bordenstein told Live Science.One gene, the second largest seen yet in phages, is made of genes previously seen in eukaryotes and bacteria fused together. This combination gene includes DNA that was found previously in prior work to help create black widow spider venom. Other genes of this phage that were previously seen in eukaryotes are known to mediate interactions between microbes and hosts, trigger the death of host cells, and help in the secretion of proteins across cell membranes.Flow of genesIt remains uncertain how this phage uses these recently discovered genes. The researchers suggested that these genes may help the phage break into animal cells or evade animal immune systems to reach and infect their bacterial hosts.It also remains unknown how this DNA has flowed between this phage and animals. Although it is likely that the genes in the phage originally came from animals, the researchers have not yet ruled out the possibility that these genes in animals originally came from phages. "We should consider all possible routes of transfer," Bordenstein said.Future research could explore how often phages get DNA from domains of life other than the one they infect. "We'd like to see a comprehensive genomic survey of viruses and their hosts," Bordenstein said.Bordenstein also noted that someday, this phage could be used to genetically modify Wolbachia. "There's been long-standing interest in genetically editing Wolbachia; people have tried vigorously and failed," he said.Finding ways to tinker with Wolbachia might help fight the Zika and dengue viruses, Bordenstein said. "When Wolbachia is present [in mosquitoes], dengue and Zika viruses are prevented from replicating at high rates," he said.Bordenstein and spouse Sarah Bordenstein, also a microbiologist at Vanderbilt University, detailed their findings Oct. 11 in the journal Nature Communications.
Physicists just confirmed a pear-shaped nucleus, and it could ruin time travel foreverPhysicists have confirmed the existence of a new form of atomic nuclei, and the fact that it’s not symmetrical challenges the fundamental theories of physics that explain our Universe.But that's not as bad as it sounds, because the discovery could help scientists solve one of the biggest mysteries in theoretical physics - where is all the dark matter? - and could also explain why travelling backwards in time might actually be impossible."We've found these nuclei literally point towards a direction in space. This relates to a direction in time, proving there's a well-defined direction in time and we will always travel from past to present," Marcus Scheck from the University of the West of Scotland told Kenneth MacDonald at BBC News.So let’s back up here, because to understand this new form of atomic nuclei, you have to get to know the old ones first. Until recently, it was established that the nuclei of atoms could be one of just three shapes - spherical, discus, or rugby ball. These shapes are formed by the distribution of electrical charge within a nucleus, and are dictated by the specific combinations of protons and neutrons in a certain type of atom, whether it’s a hydrogen atom, a zinc atom, or a complex isotope created in a lab.The common factor across all three shapes is their symmetry, and this marries nicely with a theory in particle physics known as CP-Symmetry. CP-symmetry is the combination of two symmetries that are thought to exist in the Universe: C-Symmtery and P-Symmetry. C-Symmetry, also known as charge symmetry, states that if you flip an atomic charge to its opposite, the physics of that atom should still be the same. So if we take a hydrogen atom and an anti-hydrogen atom and mess with them, both should respond in identical ways, even though they have opposite charges.P-Symmetry, also known as Parity, states that the the spatial coordinates describing a system can be inverted through the point at the origin, so that x, y, and z are replaced with −x, −y, and −z. "Your left hand and your right hand exhibit P-Symmetry from one another: if you point your thumb up and curl your fingers, your left and right hands mirror one another," Ethan Siegel from It Starts With a Bang explains.CP-Symmetry is a combination of both of these assumptions. "In particle physics, if you have a particle spinning clockwise and decaying upwards, its antiparticle should spin counterclockwise and decay upwards 100 percent of the time if CP is conserved," says Siegel. "If not, CP is violated.”The possibility that the Universe could actually violate both C-Symmetry and CP-Symmetry is one of the conditions that have been proposed to explain the mystery of antimatter in the Universe. But proving that would mean the Standard Model of Physics needs a serious rethink.According to the laws of physics, at the time of the Big Bang, equal amounts of matter and antimatter had to have been created, but now, billions of years later, we’re surrounded by heaps of matter (solid, liquid, gas, and plasma), but there appears to be almost no naturally occurring antimatter."This is a puzzling feature, as the theory of relativistic quantum mechanics suggests we should have equal amounts of the two," mathematician Gianluca Sarri from Queen's University Belfast in the UK writes for The Conversation. "In fact, no current model of physics can explain the discrepancy."Okay, so back to our atomic nuclei shapes. Most of our fundamental theories of physics are based on symmetry, so when physicists at CERN discovered an asymmetrical pear-shaped nucleus in the isotope Radium-224 back in 2013, it was a bit of a shock, because it showed that nuclei could have more mass at one end than the other. Now, three years later, the find has been confirmed by a second study, which has shown that the nucleus of the isotope Barium-144 is also asymmetrical and pear-shaped."[T]he protons enrich in the bump of the pear and create a specific charge distribution in the nucleus," Scheck told the BBC. "This violates the theory of mirror symmetry and relates to the violation shown in the distribution of matter and antimatter in our Universe."While physicists have suspected that Barium-144 has a pear-shaped nucleus for some time now, Scheck and his team finally figured out how to directly observe that, and it turns out its distortion is even more pronounced than predicted.So what does all of this have to do with time travel? It's a pretty out-there hypothesis, but Scheck says that this uneven distribition of mass and charge causes Barium-144's nucleus to 'point' in a certain direction in spacetime, and this bias could explain why time seems to only want to go from past to present, and not backwards, even if the laws of physics don't care which way it goes. Of course, there's no way of proving that without further evidence, but the discovery is yet another indication that the Universe might not be as symmetrical as the Standard Model of Physics needs it to be, and proving that could usher us into a whole new era of theoretical physics. The study has been published in Phyiscal Review Letters, and can be accessed for free at arXiv.org.
