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Cell biology

One random mutation powers multicellular life?

The Darwinian begins to sound like an overconfident historian. From ScienceDaily: All it took was one mutation more than 600 million years ago. With that random act, a new protein function was born that helped our single-celled ancestor transition into an organized multicellular organism. This release features Prehoda’s lab’s work on choranoflagellates (featured here and here already). But then notice how it all gets qualified: Prehoda and colleagues then used ancestral protein reconstruction, a technique devised at the UO by co-author Joseph W. Thornton, a biologist now at the University of Chicago. By using gene sequencing and computational methods to move backward in the evolutionary tree, researchers can see molecular changes and infer how proteins performed in the deep past. Read More ›

Do we control our gut biome? Maybe

Scientific American asks: Does our Microbiome Control Us or Do We Control It? What the article tells us is not the conventional “they utterly control us” that probably caused you to skip it before: We may be able to keep our gut in check after all. That’s the tantalizing finding from a new study published today that reveals a way that mice—and potentially humans—can control the makeup and behavior of their gut microbiome. Such a prospect upends the popular notion that the complex ecosystem of germs residing in our guts essentially acts as our puppet master, altering brain biochemistry even as it tends to our immune system, wards off infection and helps us break down our supersized burger and fries. In Read More ›

Cells poll their neighbours before moving around

From ScienceDaily: Comparing notes boosts cells sensing accuracy To decide whether and where to move in the body, cells must read chemical signals in their environment. Individual cells do not act alone during this process, two new studies on mouse mammary tissue show. Instead, the cells make decisions collectively after exchanging information about the chemical messages they are receiving. Every cell in a body has the same genome but they can do different things and go in different directions because they measure different chemical signals in their environment. Those chemical signals are made up of molecules that randomly move around. “Cells can sense not just the precise concentration of a chemical signal, but concentration differences,” Nemenman says. “That’s very important Read More ›

Origin of life, pop media, and the (almost) Big Fix

From Financial Express: Evolution is a touchy subject. Unveil a new discovery pointing towards what triggered life on Earth and a whole contingent of evolutionists, the proponents of Intelligent design (ID) and SETI (Search for Extra-Terrestrial Intelligence), spiritualists and those who believe in one “Supreme Being” will rush to reinforce that what they say is true. Yes, and hundreds of them will die, trampled by naturalists, converging on a single straw that supports them… But one thing becomes clear if examined from a purely scientific point of view: we are close yet still far from knowing when a single-cell organism stopped behaving like a single-cell entity and decided to explode into a multi-cellular being and – millions and millions of Read More ›

2016 Action item: Rewrite cell textbooks re S-phase?

From ScienceDaily: All science students learn how human cell division takes place. The copying or replication of the genome, the cell’s DNA, has until now been believed only to take place during the so-called S-phase in the cell cycle. The new results show that this is not the case, because some regions of the genome are copied only after the cell enters the next crucial phase in the cell cycle called mitosis. “It has radically altered our views and requires that the textbook view of the human cell cycle be revised,” says Professor Ian Hickson, Director of the Centre for Chromosome Stability and affiliated with the Center for Healthy Aging. There is a cancer link: This unusual pathway for copying Read More ›

Do cooperating bacteria isolate cheaters?

From ScienceDaily: For these tiny organisms it is often advantageous to divide the labor of certain metabolic processes rather than performing all biochemical functions autonomously. Bacteria that engage in this cooperative exchange of nutrients can save a significant amount of energy. Indeed, in a previous study, the researchers could already demonstrate that this division-of-metabolic-labor can positively affect bacterial growth. In the new study, they addressed the question how such cooperative interactions can persist if non-cooperating bacteria consume amino acids without providing nutrients in return. The evolutionary disadvantage that results for cooperative cells could lead to a collapse of the cross-feeding interaction. To experimentally verify this possibility, the scientists have monitored co-cultures of cooperating and non-cooperating bacteria. For this, they genetically Read More ›

Could a new kingdom of life be living in our guts?

It’s at least possible. The archaea were only discovered by Carl Woese in the 1970s. From Science Alert: A team from the Pierre and Marie Curie University in Paris, France has been attempting to redefine the way we classify the organisms living inside our colons. By studying 86 different gene families, they’ve discovered DNA sequences that are different enough to suggest they’re beyond the three forms of life that we currently recognise. Those forms are classified as bacteria, archaea, and eukaryotes. Archaea were once bundled with bacteria, but have a different biochemical make-up and can survive in more extreme conditions, whereas eukaryotes refers to fungi, plants, and animals. What the Paris team, led by Philippe Lopez and Eric Bapteste, found Read More ›

Scientists urge focus on microbiome

Microbiome = the microbes that mostly run things on our planet and in our bodies. (Or so they say. We’re just the back office.) From Carl Zimmer at New York Times: In two papers published simultaneously in the journals Science and Nature, the scientists called for a government-led effort akin to the Brain Initiative, a monumental multiyear project intended to develop new technologies to understand the human brain. … In recent decades, microbiologists have begun to map their astonishing diversity. The animal kingdom contains about 40 major groups, or phyla. Microbiologists now recognize upward of 1,000 phyla of microbes. “Plants and animals are a patina on the microbial world,” said Margaret J. McFall-Ngai of the University of Hawaii, a co-author Read More ›

Nuclear Membrane Not Just a Bubble

Phys.Org has a new summary about a new finding regarding heterochromatin repair in the nucleus which involves the nuclear membrane. In their discussion, they make some interesting points: Previously, the nuclear membrane was thought to be mostly just a protective bubble around the nuclear material, with pores acting as channels to transport molecules in and out. But in a study published on October 26 in Nature Cell Biology, a research team led by Irene Chiolo documents how broken strands of a portion of DNA known as heterochromatin are dragged to the nuclear membrane for repair. The reason why we don’t experience thousands of cancers every day in our body is because we have incredibly efficient molecular mechanisms that repair the Read More ›

Researcher claims to have simplified account of eukaryote origin

Strikes blow against “ominous specter of irreducible complexity” Archaeal ancestors of eukaryotes are not so elusive any more, says Eugene V. Koonin, Thus, eukaryotes show a qualitatively different level of cellular organization from that of archaea and bacteria, and there are no detectable evolutionary intermediates. Comparative analysis of eukaryotic cells and genomes indicates that the signature advanced functional systems of the eukaryotic cells were already present in the last eukaryotic common ancestor (LECA). These ancestral features include the actin and tubulin-based forms of cytoskeleton, the nuclear pore, the spliceosome, and the ubiquitin signaling network, to mention only several aspects of the inherent organizational complexity of eukaryotic cells [12]-[16]. The emergence of these fundamental facets of advanced cellular organization presents a Read More ›

Liquid phase separation shown to occur in cells

Contrary to earlier assumptions, and could be clue to serious disease: From ScienceDaily: Newly identified mechanism solves enduring mystery of key element of cellular organization The study focused on usually short-lived compartments called stress granules that form in cells under stress. Stress granules are just one type of the membrane-less structures or organelles that assemble as needed to handle various cell functions and then rapidly disperse. Until now, however, the mechanism underlying stress granule formation was poorly understood. Stress granules are also tied to degenerative disorders such as ALS, which is also known as Lou Gehrig’s disease. Genes encoding the protein components of stress granules are often mutated in patients with ALS and other diseases. These same proteins accumulate in Read More ›

New giant virus (proteins don’t resemble predecessor)

From ScienceDaily,: The virus takes the form of a roughly spherical particle, approximately 0.6 μm long, containing a genome of approximately 650,000 base pairs coding for more than 500 proteins. Most of these proteins bear no resemblance to those of its Siberian predecessor, Pithovirus sibericum. Furthermore, unlike Pithovirus, which only requires the cytoplasmic resources of its cellular host to multiply, Mollivirus sibericum uses the cell nucleus to replicate in the amoeba, which makes it as host-dependent as most “small” viruses. This strategy, and other specific traits, such as a deficiency in certain key enzymes that allow synthesis of its DNA building blocks, mean that Mollivirus sibericum is more similar to the common viral types, including human pathogens such as Adenovirus, Read More ›

Do centrioles carry biological information?

This pdf letter to Nature journal Cell Research is free: Paternally contributed centrioles exhibit exceptional persistence in *C. elegans *embryos If you want background re centrioles. This door is for Darwin trolls. So far as we know, noise limits are not currently in force. See also: Talk to the fossils: Let’s see what they say back

You didn’t exist before legal birth, but never mind

From Mental Floss: 10. YOUR FIRST MICROBIOME CONTACT WAS IN UTERO. For years, science considered the uterus of a pregnant woman a sterile environment, but new research published in Science Translational Medicine revealed that placentas have a unique microbiome that is different from any other part of the body (though most similar to the microbiome of the mouth). Contact with their mothers’ placentas, and the umbilical cord that attaches them, offers babies their first exposure to the bacteria that will soon colonize and support their own small bodies. Understanding this particular microbiome may also help researchers learn more to treat in utero infections and preterm births. More. By contrast, the space alien certainly exists, according to tax-funded sources, but has Read More ›

Seeing past Darwin: What’s wrong with life as “machine”

A series of articles by philosopher of biology James Barham on key new thinkers, collected together on his blog.: His first reflection concerns The gradual crumbling of the Darwinian consensus, and the rise of a new theoretical outlook in biology is one of the most significant but under-reported news stories of our time. It’s a scandal that science journalists have been so slow to pick up on this story. For, make no mistake about it, the story is huge. In science, they don’t come any bigger. Aw, in that case, the typical pom pom-wavings pop science writer would be the last to know. The story is this: The official explanation of the nature of living things—and therefore of human beings—that Read More ›