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Molecular & Cell Biology

Category: Molecular & Cell Biology

Atomic force microscopy image of the pore.
The best hiding place often lies behind enemy lines, as many bacteria such as the pathogens responsible for tuberculosis or typhoid have realized. They invade immune cells and can survive there, well hidden, for some time. To eliminate such invaders, the host macrophages can initiate a suicide program. Together with researchers at the Novartis Institute for Biomedical Research and ETH Zurich, the team led by Prof. Sebastian Hiller from the Biozentrum at the University of Basel has shown for the first time that a "death protein" perforates the cell membrane, resulting in macrophage bursting open. The re-exposed pathogens can then again be fought by the immune system.

A powerful new technology that maps the "social network" of proteins in breast cancer cells is providing detailed understanding of the disease at a molecular level and could eventually lead to new treatments, Australian scientists say.

A common feature of cancer and aging is cells' reduced ability to respond to stress-induced damage to DNA or cellular structures. Specifically, changes occur in the protective processes of apoptosis and cellular senescence, whose roles in cancer and aging are thoroughly reviewed by Cerella et al. in Current Drug Targets (Bentham Science Publishers). The authors outline the evidence that these processes are regulated by separate but intertwined pathways. Understanding the precise mechanisms, they conclude, could lead to combination therapies for cancer and aging able to harness the benefits of both apoptosis and senescence, while limiting the drawbacks of either.

Aminopeptidase N is a protein that acts as a receptor for coronaviruses, the family of viruses behind recent epidemics of SARS and MERS, among others.
BETHESDA, MD - The constant battle between pathogens and their hosts has long been recognized as a key driver of evolution, but until now scientists have not had the tools to look at these patterns globally across species and genomes. In a new study, researchers apply big-data analysis to reveal the full extent of viruses' impact on the evolution of humans and other mammals.

Every cancer starts with a single cell, and Jackson Laboratory (JAX) researchers have found a precise and reliable way -- whole-genome profiling of open chromatin -- to identify the kind of cell that leads to a given case of leukemia, a valuable key to cancer prognosis and outcome.

Immunofluorescent breast cancer cells used in this study.
Sometimes, the silencing of a gene is as important as its activation. Nonetheless, up to now, most studies on hormone-mediated gene regulation have focused on researching the factors that influence the activation of certain genes. Little attention has been paid to gene silencing.

Infertility affects about 15 percent of couples around the world. A couple's fertility depends on both the female's and male's ability to reproduce, which relies on thousands of genes working properly. In the male mouse, more than 1,000 genes are predominantly expressed in the testis, but their particular functions in reproduction are still a mystery. In a report published today in the Proceedings of the National Academy of Sciences, researchers from Baylor College of Medicine, Osaka University, University of Oulu and the Wellcome Trust Sanger Institute have discovered that 54 of the mouse testis-enriched genes, that also are expressed in humans, are not necessary for male fertility.

A molecule that enables strong communication between our brain and muscles appears to also aid essential communication between our neurons, scientists report.

When you look very close up at a butterfly wing, you can see this patchwork map of lattices with slightly different orientations (colors added to illustrate the domains).
Scientists used X-rays to discover what creates one butterfly effect: how the microscopic structures on the insect's wings reflect light to appear as brilliant colors to the eye.

A bacterial colony showing individual cells undergoing transposable element events, resulting in blue fluorescence.
"Jumping genes" are ubiquitous. Every domain of life hosts these sequences of DNA that can "jump" from one position to another along a chromosome; in fact, nearly half the human genome is made up of jumping genes. Depending on their specific excision and insertion points, jumping genes can interrupt or trigger gene expression, driving genetic mutation and contributing to cell diversification. Since their discovery in the 1940s, researchers have been able to study the behavior of these jumping genes, generally known as transposons or transposable elements (TE), primarily through indirect methods that infer individual activity from bulk results. However, such techniques are not sensitive enough to determine precisely how or why the transposons jump, and what factors trigger their activity.

Biologically speaking, we carry the outside world within us. The food we ingest each day and the trillions of microbes that inhabit our guts pose a constant risk of infection--and all that separates us from these foreign entities is a delicate boundary made of a single layer of cells.

Northwestern Medicine and University of Wisconsin-Madison (UW) scientists have identified a gene that causes severe glaucoma in children. The finding, published in The Journal of Clinical Investigation, validates a similar discovery made by the scientists in mice two years ago and suggests a target for future therapies to treat the devastating eye disease that currently has no cure.

Johan Flygare and Sandra Capellera.
Eight days. That's how long it takes for skin cells to reprogram into red blood cells. Researchers at Lund University in Sweden, together with colleagues at Center of Regenerative Medicine in Barcelona, have successfully identified the four genetic keys that unlock the genetic code of skin cells and reprogram them to start producing red blood cells instead.

For a long time dismissed as "junk DNA", we now know that also the regions between the genes fulfil vital functions. Mutations in those DNA regions can severely impair development in humans and may lead to serious diseases later in life. Until now, however, regulatory DNA regions have been hard to find. Scientists around Prof. Julien Gagneur, Professor for Computational Biology at the Technical University of Munich (TUM) and Prof. Patrick Cramer at the Max Planck Institute (MPI) for Biophysical Chemistry in Göttingen have now developed a method to find regulatory DNA regions which are active and controlling genes.

New identification of a gene involved in the fracture healing process could lead to the development of new therapeutic treatments for difficult-to-heal injuries.

New research by Steven Laviolette's research team at Western University is contributing to a better understanding of the ways opiate-class drugs modify brain circuits to drive the addiction cycle. Using rodent models of opiate addiction, Dr. Laviolette's research has shown that opiates affect pathways of associative memory formation in multiple ways, both at the level of anatomy (connections between neurons) and at the molecular levels (how molecules inside the brain affect these connections). The identification of these opiate-induced changes offers the best hope for developing more effective pharmacological targets and therapies to prevent or reverse the effect of opiate exposure and addiction. These results were presented at the 10th Annual Canadian Neuroscience Meeting, taking place May 29 to June 1 2016, in Toronto, Canada.

Scientists at the University of Birmingham are a step closer to understanding the role of the gene BRCA1. Changes in this gene are associated with a high risk of developing breast and ovarian cancer.

Just as members of an orchestra need a conductor to stay on tempo, neurons in the brain need well-timed waves of activity to organize memories across time. In the hippocampus--the brain's memory center--temporal ordering of the neural code is important for building a mental map of where you've been, where you are, and where you are going. Published on May 30 in Nature Neuroscience, research from the RIKEN Brain Science Institute in Japan has pinpointed how the neurons that represent space in mice stay in time.

Tailor-made ratiometric sensors make baker's yeast cells light up green, as Georgia Tech scientists use it to track the movements of the essential toxin heme.
A pinch of poison is good for a body, at least if it's heme.

Stylized graphic of SEC-SAXS data (with cyan cross-section showing the elution profile and magenta cross-section showing scattering profile) and the structure of the activated phenylalanine hydroxylase
Using a powerful combination of techniques from biophysics to mathematics, researchers have revealed new insights into the mechanism of a liver enzyme that is critical for human health. The enzyme, phenylalanine hydroxylase, turns the essential amino acid phenylalanine -- found in eggs, beef and many other foods and as an additive in diet soda -- into tyrosine, a precursor for multiple important neurotransmitters.

A new study from MIT neuroscientists reveals that a gene mutation associated with autism plays a critical role in the formation and maturation of synapses -- the connections that allow neurons to communicate with each other.

Unlike aspirin, bone marrow doesn't come with a neatly printed label with dosage instructions. However, a new study published in Cell Reports provides clues about how the dose of transplanted bone marrow might affect patients undergoing this risky procedure, frequently used to treat cancer and blood diseases.

These are DNA double-strand breaks, introduced by ionizing radiation or other mechanisms, are repaired rapidly and precisely in normal cells (right pathway). In contrast, compromised Tel1 activation with inefficient end...
A group of researchers at Osaka University found that if DNA damage response (DDR) does not work when DNA is damaged by radiation, proteins which should be removed remain instead, and a loss of genetic information can be incited, which, when repaired incorrectly, will lead to the tumor formation.

Voltage-gated calcium channels open in unison, rather than independently, to allow calcium ions into and activate excitable cells such as neurons and muscle cells, researchers with UC Davis Health System and the University of Washington have found.

Retroviral DNAs integrate into host genomes, but their expression is normally repressed by cellular defense mechanisms. As an Ludwig-Maximilians-Universitaet (LMU) in Munich team now shows, when these measures fail, accumulation of viral proteins may trigger programmed cell death.

Verrucosispora maris, the bacteria in which the enzyme was found.
Scientists at the Universities of Bristol and Newcastle have uncovered the secret of the 'Mona Lisa of chemical reactions' - in a bacterium that lives at the bottom of the Pacific Ocean.

A new study finds that the more than 90,000 species of mushrooms, molds, yeasts and other fungi found everywhere in the soil, water and air may owe their abilities to grow, spread, and even cause disease to an opportunistic virus they caught more than a billion years ago.

This is a tomographical slice of a budding yeast cell defective in condensin function (ycg1-2). The division septum advances on incompletely segregated chromosomes.
The cells in our bodies are constantly dividing. From embryonic development to adult life, cell division is necessary for tissue growth and renewal. During division, cells must duplicate their genetic material (or DNA) and ensure identical copies are passed along to the daughter cells. The entire process must work perfectly. If not, the next generation of cells will not have the genetic material necessary to function properly. Their role becomes especially relevant in situations in which cells proliferate rapidly, like embryonic development or tumor proliferation.

This is a snapping turtle.
The sex of many reptile species is set by temperature. New research reported in the journal GENETICS identifies the first gene associated with temperature-dependent sex determination in any reptile. Variation at this gene in snapping turtles contributes to geographic differences in the way sex ratio is influenced by temperature. Understanding the genetics of sex determination could help predict how reptiles will evolve in response to climate change.

A 3-D rendering of a fluorescence image maps the piconewton forces applied by T cells. The height and color indicates the magnitude of the applied force.
T cells, the security guards of the immune system, use a kind of mechanical "handshake" to test whether a cell they encounter is a friend or foe, a new study finds.

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