Cell biology

From ScienceDaily: Prior to cell division, chromosomes are seemingly a jumbled mess. During cell division, parent cell chromosomes and their duplicates sort themselves out by condensing, becoming thousands of times more compact than at any other time. Researchers have long assumed that genes become “silent” during cell division, not being transcribed into proteins or regulatory molecules. This has left open the question of how genes get properly re-activated after cell division. Now, researchers in the Perelman School of Medicine at the University Pennsylvania have found that gene expression actually continues during cell replication. Their findings are published this week in Science. … Although chromosomes are extremely compact during cell division, with sequences for regulatory molecules buried and previously presumed to Read More ›

Re two recent flaps around the possible discovery of soft dinosaur tissue, Senior Scientist at the Geoscience Research Institute Tim Standish writes from Loma Linda U to offer a perspective on YEC Mark Armitage’s find vs. Mary Schweitzer’s find: It isn’t replication, but it is strong verification. There are lots of other peer reviewed papers out there ranging from halophilic bacteria being resurrected from the dead in samples that are supposed to be hundreds of millions of years old to more recent finds, all point to the unexpected presence of biological samples that are supposed to be millions of years old. From my perspective, this is one of those things that needs very careful explaining if the current understanding of dating Read More ›

From Biologic Institute’s Ann Gauger, on J. Scott Turner’s forthcoming Purpose and Desire: at Evolution News & Views: Claude Bernard (1813-1878) was a French physiologist, one of the most famous scientists of his age, so famous that he appeared in poems, novels, and memoirs of the period both in France and abroad. Think Albert Einstein. Now, however, he is most famous for his idea that the miliéu interieur, or internal environment of living things, must remain constant to sustain and maintain life. This idea is given the name homeostasis, defined as a “self-regulating process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival. If homeostasis is successful, life continues; if unsuccessful, disaster Read More ›

From Robert F. Service at Science: For the last 20 years, Mary Schweitzer, a paleontologist at North Carolina State University in Raleigh, has amassed a wealth of evidence that she’s isolated protein fragments from dinosaurs as much as 80 million years old. That bucks the conventional wisdom among paleontologists who argue that proteins, which are made of chains of amino acids, can’t survive more than 1 million years or so. So far, no group other than Schweitzer and her collaborators has managed to replicate the findings. She contends that’s because others don’t follow her methods. If Schweitzer is right and outside researchers eventually do confirm her findings, it could transform dinosaur paleontology into a molecular science. That, in turn, could Read More ›

From Shawna Williams at The Scientist: Genetic variants linked to a predisposition for Alzheimer’s disease and heavy smoking are less common in older people than in younger people, researchers report today (September 5) in PLOS Biology. Their study analyzed genetic alleles in two large genomic databases to find those associated with longevity, which they used as a proxy for evolutionary fitness. “Nobody’s really had the data to measure single-generation shifts in allele frequencies in humans before,” says geneticist Jonathan Pritchard of Stanford University who was not involved in the study. “It’s an important part of understanding how evolution works to go down to the smallest scale of evolutionary change, namely, what’s happening in one generation.” More. … But how would Read More ›

From an article in Biology Direct, Breath-giving cooperation: critical review of origin of mitochondria hypotheses: Major unanswered questions point to the importance of early ecology: Abstract: The origin of mitochondria is a unique and hard evolutionary problem, embedded within the origin of eukaryotes. The puzzle is challenging due to the egalitarian nature of the transition where lower-level units took over energy metabolism. Contending theories widely disagree on ancestral partners, initial conditions and unfolding of events. There are many open questions but there is no comparative examination of hypotheses. We have specified twelve questions about the observable facts and hidden processes leading to the establishment of the endosymbiont that a valid hypothesis must address. We have objectively compared contending hypotheses under Read More ›

First, from Casey Luskin in 2014 on Lee Spetner’s The Evolution Revolution here: Many ENV readers might have read, or at least heard of, a well-argued 1996 book by Lee Spetner, Not By Chance. Spetner, who holds a PhD in physics from MIT, has recently published a sequel titled The Evolution Revolution: Why Thinking People Are Rethinking the Theory of Evolution (Judaica Press, 2014). Spetner goes through many examples of non-random evolutionary changes that cannot be explained in a Darwinian framework. He covers some of the natural genetic engineering mechanisms reported by James Shapiro, which can modify an organism’s genome during a period of stress. Of course the big criticism of Shapiro’s arguments is that he never explains how those Read More ›

From ScienceDaily: Mitochondria, which exist within human cells but have their own DNA, need many different proteins to function — but the process of how they get these has never been imaged in detail. Now a study led by Dr Vicki Gold, of the University of Exeter, has shown that some ribosomes — the tiny factories of cells which produce proteins — are attached to mitochondria. This can explain how proteins are pushed into mitochondria whilst they are being made. The findings open new avenues for studying protein targeting and mitochondrial dysfunction, which has been implicated in diseases including cancer and neurodegenerative disorders such as Parkinson’s. “Proteins are responsible for nearly all cellular processes. The cell has to make a Read More ›

From ScienceDaily: Mammalian perineal structure derived from septation of the cloaca is an important evolutionary innovation that allows myriad anatomical configurations, diverse reproductive strategies, and precise excretory control available only to mammals. The researchers were surprised to discover that, despite the perineum’s structural complexity, the muscles of the mammalian perineum show a reemergence of a simple pattern of body wall layering that dates back more than 360 million years ago — during the origin of tetrapods, the first vertebrates to move out of the water onto land. [color emphasis added] Basal vertebrates, such as fish, organize their body wall into two muscular layers that are important for swimming. However, with the transition from water to land, the body wall of Read More ›

From ScienceDaily: A type of mouse widely used to assess how the human immune system responds to transplanted stem cells does not reflect what is likely to occur in patients, according to a study by researchers at the Stanford University School of Medicine. The researchers urge further optimization of this animal model before making decisions about whether and when to begin wide-scale stem cell transplants in humans. Known as “humanized” mice, the animals have been engineered to have a human, rather than a murine, immune system. Researchers have relied upon the animals for decades to study, among other things, the immune response to the transplantation of pancreatic islet cells for diabetes and skin grafts for burn victims. However, the Stanford Read More ›

From ScienceDaily: Dr Brocks said the rise of algae triggered one of the most profound ecological revolutions in Earth’s history, without which humans and other animals would not exist. “Before all of this happened, there was a dramatic event 50 million years earlier called Snowball Earth,” he said. “The Earth was frozen over for 50 million years. Huge glaciers ground entire mountain ranges to powder that released nutrients, and when the snow melted during an extreme global heating event rivers washed torrents of nutrients into the ocean.” Dr Brocks said the extremely high levels of nutrients in the ocean, and cooling of global temperatures to more hospitable levels, created the perfect conditions for the rapid spread of algae. It was Read More ›

Documentary evidence offered here Didn’t they used to say that the bugs get everybody in the end? See also: From Philip Cunningham: Darwinian Materialism vs Quantum Biology

From Catherine Offord at the Scientist: Circular RNAs (circRNAs) have attracted growing attention in recent years, but their function in living organisms has long remained a mystery. Now, researchers report that one circRNA, Cdr1as, regulates microRNA levels in the mammalian brain, and that its removal results in abnormal neuronal activity and behavioral impairments in mice. The findings were published today (August 10) in Science. “There are few papers where you can really say it’s a breakthrough,” says Sebastian Kadener, a neuroscientist and circRNA researcher at Brandeis University who was not involved in the work. “But this paper is really exciting. It’s the first real demonstration of a function of these molecules in vivo in an animal.”More. A breakthrough now but Read More ›

From Ana Lopes at Physics: Electronic tags in the form of radio-frequency identification (RFID) devices are everywhere. They show up in key cards, e-passports, toll passes, you name it. H.-S. Philip Wong, Ada Poon, and colleagues at Stanford University, California, have now made an RFID tag that is small enough to be placed inside a cell. Such tags might one day be used to track and monitor individual cells wirelessly. Paper. (paywall) More. Tracking cells should help us understand more of the specified complexity of life. See also: Tiny molecular machines that keep chromosome numbers correct have been identified

From ScienceDaily:“During cell division, a mother cell divides into two daughter cells, and during this process the DNA in the mother cell, wrapped up in the form of chromosomes, is divided into two equal sets. To achieve this, rope-like structures called microtubules capture the chromosomes at a special site called the kinetochore, and pull the DNA apart,” said Dr Viji Draviam, senior lecturer in structural cell and molecular biology from QMUL’s School of Biological and Chemical Sciences. “We have identified two proteins — tiny molecular machines — that enable the correct attachment between the chromosomes and microtubules. When these proteins don’t function properly, the cells can lose or gain a chromosome. This finding gives us a glimpse of an important Read More ›