Molecular & Cell Biology

Category: Molecular & Cell Biology

Researchers at the BBSRC-funded Babraham Institute, in collaboration with the Wellcome Trust Sanger Institute Single Cell Genomics Centre, have developed a powerful new single-cell technique to help investigate how the environment affects our development and the traits we inherit from our parents. The technique can be used to map all of the 'epigenetic marks' on the DNA within a single cell. This single-cell approach will boost understanding of embryonic development, could enhance clinical applications like cancer therapy and fertility treatments, and has the potential to reduce the number of mice currently needed for this research.

An international team of researchers, including scientists from the Max Planck Institute for Medical Research in Heidelberg, has just a reported a major step in understanding photosynthesis, the process by which the Earth first gained and now maintains the oxygen in its atmosphere and which is therefore crucial for all higher forms of life on earth.

In this image, the cells are stained red for cell protrusion, yellow for cell membrane and blue for nucleus.
Insights into how cells move through the body could lead to innovative techniques to stop cancer cells from spreading and causing secondary tumours, according to new UCL research.

This gif of membrane-anchored Ras (red) and individual SOS molecules (green) shows individual SOS molecules corralled into nanofabricated patches where all the membrane-associated Ras molecules they activate can be trapped.
A breakthrough discovery into how living cells process and respond to chemical information could help advance the development of treatments for a large number of cancers and other cellular disorders that have been resistant to therapy. An international collaboration of researchers, led by scientists with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, have unlocked the secret behind the activation of the Ras family of proteins, one of the most important components of cellular signaling networks in biology and major drivers of cancers that are among the most difficult to treat.

One of the knots grows in size, while the other diffuses along the contour of the former.
Physicists of Johannes Gutenberg University Mainz (JGU) and the Graduate School of Excellence "Materials Science in Mainz" (MAINZ) have been able with the aid of computer simulations to confirm and explain a mechanism by which two knots on a DNA strand can interchange their positions. For this, one of the knots grows in size while the other diffuses along the contour of the former. Since there is only a small free energy barrier to swap, a significant number of crossing events have been observed in molecular dynamics simulations, i.e., there is a high probability of such interchange of positions.

This is a cross section of an injury in the large intestine with the intestinal epithelium shown in red.
Over 3.5 million people in Europe and the US suffer from Crohn's disease or ulcerative colitis – the two most common forms of IBD. Chronic bowel inflammation is caused by an overreaction of the immune system to the bacteria which naturally occur in the gut. "This overreaction can come about if, for example, the anti-stress mechanism in the cells of the intestinal mucosa does not function correctly," explains Prof. Dirk Haller of the TUM Chair of Nutrition and Immunology.

The molecular building blocks that make up DNA absorb ultraviolet light so strongly that sunlight should deactivate them – yet it does not. Now scientists have made detailed observations of a "relaxation response" that protects these molecules, and the genetic information they encode, from UV damage. The experiment at the Department of Energy's SLAC National Accelerator Laboratory focused on thymine, one of four DNA building blocks. Researchers hit thymine with a short pulse of ultraviolet light and used a powerful X-ray laser to watch the molecule's response: A single chemical bond stretched and snapped back into place within 200 quadrillionths of a second, setting off a wave of vibrations that harmlessly dissipated the destructive UV energy.

Case Western Reserve School of Medicine scientists have made an extraordinary double discovery. First, they have identified thousands of novel long non-coding ribonucleic acid (lncRNA) transcripts. Second, they have learned that some of them defy conventional wisdom regarding lncRNA transcripts, because they actually do direct the synthesis of proteins in cells.

Sperm (blue) latch onto a control egg (left) but can't bind to an egg lacking the glycoprotein ZP2 (right).
Before it can fertilize an egg, a sperm has to bind to and bore through an outer egg layer known as the zona pellucida. Despite decades of research, some of the biological mechanisms behind this process remain unclear. A study in The Journal of Cell Biology now identifies the protein in the zona pellucida that sperm latch onto.

DNA methylation has been identified as a potential biomarker of response to etanercept and adalimumab in patients with rheumatoid arthritis (RA) according to preliminary results from one of the largest methylome-wide investigations of treatment response to anti-TNF therapies.1 These data, presented today at the European League Against Rheumatism Annual Congress (EULAR 2014), bring clinicians a step closer to being able to personalise a patient's treatment pathway.

By cataloging over 18,000 proteins, researchers from TUM have produced an almost complete inventory of the human proteome. This information is now freely available in the ProteomicsDB database, which is a joint development of TUM and software company SAP. The database includes information for example on the types, distribution, and abundance of proteins in various cells and tissues as well as in body fluids.

This shows crosslink-inducing agents used in chemotherapy.
Environmental influences such as ionizing radiation, intense heat or various chemical substances damage the DNA constantly. Only thanks to efficient repair systems can mutations – changes in the DNA – largely be prevented. DNA crosslinks that covalently link both strands of the DNA double helix are among the most dangerous DNA lesions. Crosslinks block DNA replication and can thus cause cell death. Moreover, their faulty repair can trigger the development of tumors. Crosslink repair is highly complex and only vaguely understood today. A team of cancer researchers headed by Alessandro Sartori from the University of Zurich now reveals interesting details as to how cells recognize crosslink damage. In their study recently published in Cell Reports, the scientists demonstrate that the interplay between two specific proteins is crucial for the flawless repair of crosslink damage.

An international team of scientists has made a major step forward in our understanding of how enzymes 'edit' genes, paving the way for correcting genetic diseases in patients.

Stimulation of a certain population of neurons within the brain can alter the learning process, according to a team of neuroscientists and neurosurgeons at the University of Pennsylvania. A report in the Journal of Neuroscience describes for the first time that human learning can be modified by stimulation of dopamine-containing neurons in a deep brain structure known as the substantia nigra. Researchers suggest that the stimulation may have altered learning by biasing individuals to repeat physical actions that resulted in reward.

This image shows a GroEL/ES nano-cage (light blue and white) with encapsulated substrate protein (orange).
Proteins are the workhorses of the cell and thus responsible for almost all biological functions including metabolism, signal transmission or the determination of the cell's shape. However, before they can fulfill their various tasks, the chain-like molecules must first adopt an intricate three-dimensional conformation. This process is called protein folding and is one of the most important processes in biology. In fact, in the event of improper folding, proteins are often no more able to carry out their duties, or even tend to clump together in aggregates. This in turn can lead to severe diseases like Alzheimer's or Parkinson's. In order to avoid this, specialized proteins, the so-called chaperones, help other proteins to adopt their proper shape.

From left to right are: genital ridge at the time of sex determination; fetal testis and seminiferous cords; fluorescent adult testis; cross-section of adult seminiferous tubule.
A team of researchers from the University of Geneva (UNIGE) has been involved in a thorough genetic investigation based on the case of a child suffering from the Nivelon-Nivelon-Mabille Syndrome, a complex condition characterised mainly by a sexual development disorder. Following a genome analysis of the patient and parents, the scientists, led by Serge Nef, Professor of the Department of Genetic Medicine and Development in the Faculty of Medicine, have identified not only the gene, but also the protein-producing mechanism, whose malfunctioning causes the syndrome in question. Published in PLOS Genetics, these results make way for genetic tests, thus improving treatment for patients and their families.

This is a fatty liver with SIRT7. The microscope images show the liver tissue of control animals (left) and mice that lack the SIRT7 gene magnified by a factor of...
The long-term consumption of too much high-energy and high-fat food leads to overweight. Behind this trivial statement lies the extremely complex regulation of lipid metabolism. Together with colleagues from Japan, scientists from the Max Planck Institute for Heart and Lung Research in Bad Nauheim have now discovered that the Sirt7 gene plays a central role in energy metabolism. Despite consuming high-fat food, genetically modified mice that lack the gene maintain their normal weight.

The zebrafish is used as a model organism for research into the embryonic development of vertebrates.
Early embryonic development of vertebrates is controlled by the genes and their "grammar". Decoding this grammar might help understand the formation of abnormalities or cancer or develop new medical drugs. For the first time, it is now found by a study that various mechanisms of transcribing DNA into RNA exist during gene expression in the different development phases of zebrafish. This study is presented by KIT researchers in the journal "Nature".

Scientists from the Florida campus of The Scripps Research Institute (TSRI) have identified a protein complex that plays a critical but previously unknown role in learning and memory formation.

Scientists have uncovered a new way the immune system may fight cancers and viral infections. The finding could aid efforts to use immune cells to treat illness.

This shows active droplets.
Droplets of filamentous material enclosed in a lipid membrane: these are the models of a "simplified" cell used by the SISSA physicists Luca Giomi and Antonio DeSimone, who simulated the spontaneous emergence of cell motility and division - that is, features of living material - in inanimate "objects". The research is one of the cover stories of the April 10th online issue of the journal Physical Review Letters.

Here are Cian O'Donnell and Terry Sejnowski.
Scientists at the Salk Institute have created a new model of memory that explains how neurons retain select memories a few hours after an event.

Mitochondria in hepatitis C-infected cells (bottom row) are self-destructing. The self-annihilation process explains the persistance and virulence of the virus in human liver cells.
Researchers at the University of California, San Diego School of Medicine have identified a mechanism that explains why people with the hepatitis C virus get liver disease and why the virus is able to persist in the body for so long.

Researchers have found a major piece of genetic evidence that confirms the role of a group of virus-fighting genes in cancer development.

This is a confocal laser scanning microcope image of an early embryo with surrounding placental endosperm cells.
A new generation of high yield plants could be created following a fundamental change in our understanding of how plants develop.

Synthetic genetic circuitry created by researchers at Rice University is helping them see, for the first time, how to regulate cell mechanisms that degrade the misfolded proteins implicated in Parkinson's, Huntington's and other diseases.

This image shows the structure of the sodium pump, which researchers reveal to be more versatile than previously thought.
A study in The Journal of General Physiology provides new evidence that the ubiquitous sodium pump is more complex—and more versatile—than we thought.

This image shows the evolutionary relationships among the species analyzed for conserved non-coding sequences. 'Myr' stands for million years ago. Ellipses are approximate times of whole-genome duplications.
DNA is the molecule that encodes the genetic instructions enabling a cell to produce the thousands of proteins it typically needs. The linear sequence of the A, T, C, and G bases in what is called coding DNA determines the particular protein that a short segment of DNA, known as a gene, will encode. But in many organisms, there is much more DNA in a cell than is needed to code for all the necessary proteins. This non-coding DNA was often referred to as "junk" DNA because it seemed unnecessary. But in retrospect, we did not yet understand the function of these seemingly unnecessary DNA sequences.

Case Western Reserve University researchers have discovered a novel population of neutrophils, which are the body's infection control workhorses. These cells have an enhanced microbial killing ability and are thereby better able to control infection.

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