Cell biology

Sources here. See also: Ribosome precisely structured for cell growth

From ScienceDaily: Optimization for self-production may explain key features of ribosomes, the protein production factories of the cell, reported researchers from Harvard Medical School in Nature on July 20. In a new study, a team led by Johan Paulsson, professor of systems biology at Harvard Medical School, mathematically demonstrated that ribosomes are precisely structured to produce additional ribosomes as quickly as possible, in order to support efficient cell growth and division. … Ribosomes are composed of a puzzlingly large number of different structural proteins — anywhere from 55 to 80, depending on organism type. These proteins are not just more numerous than expected, they are unusually short and uniform in length. Ribosomes are also composed of two to three strands Read More ›

From ScienceDaily: Using 3D laser scans of growing plants, Salk scientists found that the same universal design principles that humans use to engineer networks like subways also guide the shapes of plant branching architectures. The work, which appears in the July 26, 2017, issue of Cell Systems, could help direct strategies to increase crop yields or breed plants better adapted to climate change. Well, that sure beats doomsaying, fascism, and war. Engineered transportation networks, whether for moving people or power, need to balance the cost of construction with providing efficient transport. Think of a subway system: If the main objective when designing it is to get people from the suburbs to downtown as quickly as possible, each suburb will have Read More ›

Ed Yong tells us at the Atlantic: In the 150 years since Schwendener, biologists have tried in vain to grow lichens in laboratories. Whenever they artificially united the fungus and the alga, the two partners would never fully recreate their natural structures. It was as if something was missing—and Spribille might have discovered it. He has shown that largest and most species-rich group of lichens are not alliances between two organisms, as every scientist since Schwendener has claimed. Instead, they’re alliances between three. All this time, a second type of fungus has been hiding in plain view. “There’s been over 140 years of microscopy,” says Spribille. “The idea that there’s something so fundamental that people have been missing is stunning.” Read More ›

From Jordana Cepelewicz at Quanta: For over a century, distinctions between types of cells relied on how they appeared under a microscope: their shapes, sizes, locations and their uptake of staining dyes. Recent decades, however, witnessed a shift to molecular methods that use fluorescently labeled antibodies to target protein markers on the cell’s surface. Although this approach allowed researchers to isolate more cell types, it was not enough, according to Hacohen. Until 2009, biologists could analyze cells only in bulk, averaging signals from multitudes of them to get a picture of what was going on in a tissue. When sequencing RNA from individual cells finally became possible, the initial analyses were what Hacohen called “biased” and “shallow” because the few Read More ›

From BEC CREW at ScienceAlert: Researchers have discovered that the lungs play a far more complex role in mammalian bodies than we thought, with new evidence revealing that they don’t just facilitate respiration – they also play a key role in blood production. In experiments involving mice, the team found that they produce more than 10 million platelets (tiny blood cells) per hour, equating to the majority of platelets in the animals’ circulation. This goes against the decades-long assumption that bone marrow produces all of our blood components. More. W|e are expected to believe that that all just happened by natural selection acting on random mutations and that no source of information is required. Sure. The article in Nature. Abstract: Read More ›

From Phys.org: The transition from an egg to a developing embryo is one of life’s most remarkable transformations. Yet little is known about it. Now Whitehead Institute researchers have deciphered how one aspect—control of the all-important translation of messenger RNAs (mRNAs) into proteins—switches as the egg becomes an embryo. That shift is controlled by a beautiful mechanism, which is triggered at a precise moment in development and automatically shuts itself off after a narrow window of 20 to 90 minutes. As an egg develops, it stockpiles mRNAs from the mother because it will not have time to create new mRNAs during the rapid development of a very early embryo. When fertilized the egg becomes an embryo, the stashed maternal mRNAs Read More ›

From Veronique Greenwood at Nova Next: In 1987, a group of researchers in France discovered something peculiar. When they protected single-celled organisms from background radiation—the sort that comes from cosmic rays and radioactive rocks—the creatures’ growth was stunted. Colonies that receive a background dose of radiation actually grew more quickly than their shielded brethren. That’s radiation—not vitamins, not nutrition, not anything people generally suggest you should get more of. Was background radiation somehow required for life? … It’s a peculiar finding—why would being without radiation make cells more vulnerable? One theory is that very low doses of radiation can cause cells to keep their repair machinery switched on, and those without it are unprepared, like a runner who skipped one Read More ›

From Mark Buchanan at Nature Physics: The origin of life is among the deepest unexplained mysteries. How did the first self-replicating entities emerge, providing the material on which the selective mechanism of evolution could then operate? The most primitive known self-replicating forms of life are far too complex to have sprung from the pre-evolutionary environment through… More. You’d have to pay to read more. Not recommended. If they had any workable naturalist idea, the world would deafen at the sound. If they thought it required intelligence, their careers would be ruined. See also: What we know and don’t know about the origin of life

From ScienceDaily: Contrary to expectations, this latest study reveals that each gene doesn’t have an ideal location in the cell nucleus. Instead, genes are always on the move. Published in the journal Nature, researchers examined the organisation of genes in stem cells from mice. They revealed that these cells continually remix their genes, changing their positions as they progress though different stages. This work, which has also inspired a musical collaboration, suggests that moving genes about in this way could help cells to fine-tune the volume of each gene to suit the cell’s needs. Scientists had believed that the location of genes in cells are relatively fixed with each gene having it’s rightful place. Different types of cells could organise Read More ›

From ScienceDaily: The researchers discovered that wtf genes poison their prey. “The strategy that wtf selfish genes employ is to poison all the developing gametes, but then keep the antidote for themselves,” says Zanders, a Stowers assistant investigator. “The gametes that inherit the selfish genes are also exposed to the poison, but they don’t succumb to it because they have the antidote. And the gametes that don’t inherit the selfish gene are destroyed.” Zanders likens the mechanism to a dinner party in a murder mystery novel, in which everyone, including the host, is poisoned, but the host has the antidote. … The findings are particularly interesting from an evolutionary perspective, Zanders says. “The wtf genes make a poison that has Read More ›

From Amy Maxmen at Nature News: tenOever speculates that RNAse III proteins originally helped bacteria to maintain their own RNA, and that bacteria later deployed the proteins against the genetic material of viruses. He points out the occurrence of RNAse III proteins in immune responses throughout the tree of life. For instance, some CRISPR systems, a virus-fighting response in archaea and bacteria, include RNAse III proteins. Plants and invertebrates deploy the proteins in RNAi. And although vertebrates rely on interferons for viral control, this study now shows that Drosha still chases after viruses, in the same way a pet Golden Retriever — a dog bred to retrieve waterfowl — fetches a stick as if it were a fallen duck. Donald Read More ›

From ScienceDaily: Drexel University and Georgia Institute of Technology researchers have discovered how the Rad52 protein is a crucial player in RNA-dependent DNA repair. The results of their study, published in Molecular Cell, reveal a surprising function of the homologous recombination protein Rad52. They also may help to identify new therapeutic targets for cancer treatment. Radiation and chemotherapy can cause a DNA double-strand break, one of the most harmful types of DNA damage. The process of homologous recombination — which involves the exchange of genetic information between two DNA molecules — plays an important role in DNA repair, but certain gene mutations can destabilize a genome. For example, mutations in the tumor suppressor BRCA2, which is involved in DNA repair Read More ›

From BEC Crew at ScienceAlert: Here’s proof of how far we’ve come in science – in a world-first, researchers have recorded up-close footage of a single DNA molecule replicating itself, and it’s raising questions about how we assumed the process played out. The real-time footage has revealed that this fundamental part of life incorporates an unexpected amount of ‘randomness’, and it could force a major rethink into how genetic replication occurs without mutations. “It’s a real paradigm shift, and undermines a great deal of what’s in the textbooks,” says one of the team, Stephen Kowalczykowski from the University of California, Davis. More. It may not be as random as they think. A subway crowd’s movements may appear random at times, but Read More ›

From Suzan Mazur, author of Origin of Life Circus at Huffington Post, an interview with George Urtel: Georg Urtel: The hairpins are just being replicated. They are being replicated very inefficiently. Again, this has to do with the nature of the secondary structures. The hairpin structure is inhibiting because what the hairpin structure does is it forms a double helix with itself. When you have such a structure, the primer can’t bind. Suzan Mazur: What would you say is the significance of this experiment? Hasn’t it been known for many years that hairpins have a role in replication and recombination? Georg Urtel: Yes. The hairpin structure you find in all kinds of RNA enzymes, but the point here is that Read More ›