Molecular & Cell Biology

Category: Molecular & Cell Biology


Stills from time-lapse video showing transdifferentiation of pre-B cells into yeast-eating macrophages.
All it takes is one molecule to reprogram an antibody-producing B cell into a scavenging macrophage. This transformation is possible, new evidence shows, because the molecule (C/EBPa, a transcription factor) "short-circuits" the cells so that they re-express genes reserved for embryonic development. The findings appear July 30 in Stem Cell Reports, the journal of the International Society for Stem Cell Research.

Since mice share 90 percent of our genes they play an important role in understanding human genetics. The European Mouse Disease Clinic (EUMODIC) brought together scientists from across Europe to investigate the functions of 320 genes in mice. Over half of these genes had no previously known role, and the remaining genes were poorly understood.

By studying the yeast used in beer- and bread-making, researchers at the University of Pittsburgh School of Medicine have uncovered the mechanism by which ancient proteins repair DNA damage and how their dysfunction could lead to the development of tumors. The findings, published online today in Nature Communications, could lead to new ways to tailor cancer therapies.

A multidisciplinary team at Yale, led by Yale Cancer Center members, has defined a subgroup of genetic mutations that are present in a significant number of melanoma skin cancer cases. Their findings shed light on an important mutation in this deadly disease, and may lead to more targeted anti-cancer therapies.


This is an example of hierarchical folded package of globule.
A group of researchers from the Lomonosov Moscow State University tried to address one of the least understood issues in the modern molecular biology, namely, how do strands of DNA pack themselves into the cell nucleus. Scientists concluded that packing of the genome in a special state called "fractal globule", apart from other known advantages of this state, allows the genetic machinery of the cell to operate with maximum speed due to comperatively rapid thermal diffusion. The article describing their results was published in Physical Review Letters.

Pharmaceutical sciences researchers at Washington State University have discovered a protein's previously unknown role in cell division.

Swedish researchers at Uppsala University and the Karolinska Institute have found that genes that control the biological clocks in cells throughout the body are altered after losing a single night of sleep, in a study that is to be published in the Journal of Clinical Endocrinology and Metabolism.

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Researchers have shown that the levels of two proteins present in blood and cerebrospinal fluid increase significantly at different time points following traumatic brain injury (TBI), confirming their potential value as biomarkers of trauma-related brain damage. The researchers linked the changes in circulating UCH-L1 and GFAP proteins in rats to brain tissue damage and neuronal degeneration seen on examination of the rat brains and present their findings in an article published in Journal of Neurotrauma, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the Journal of Neurotrauma website.

Research findings obtained over the past decades increasingly indicate that stored memories are coded as permanent changes of neuronal communciation and the strength of neuronalinterconnections. The learning process evokes a specific pattern of electrical activity in these cells, which influences the response behavior to incoming signals, the expression of genes and the cellular morphology beyond the learning process itself.


Researcher Marie Hjelmseth Aune at CEMIR, the Centre of Molecular Inflammation Research at the Norwegian University of Science and Technology, looks at a macrophage engulfing an invading bacterium.
The human immune system is a powerful and wonderful creation. If you cut your skin, your body mobilizes a series of different proteins and cells to heal the cut. If you are infected by a virus or bacteria, your immune system responds with a series of cells that attack the invader and neutralize it.

DNA, the molecular foundation of life, has new tricks up its sleeve. The four bases from which it is composed snap together like jigsaw pieces and can be artificially manipulated to construct endlessly varied forms in two and three dimensions. The technique, known as DNA origami, promises to bring futuristic microelectronics and biomedical innovations to market.


Each of the five panels shows a memory snapshot created by hundreds of place cells while the rat was physically stationary at the top of the 1.8 m track
By using electrode implants to track nerve cells firing in the brains of rats as they plan where to go next, Johns Hopkins scientists say they have learned that the mammalian brain likely reconstructs memories in a way more like jumping across stepping stones than walking across a bridge. A summary of their experiments, published in the journal Science on July 10, sheds light on what memories are and how they form, and gives clues about how the system can fail.

Case Western Reserve researchers already demonstrated that a single protein plays a pivotal role in the use of nutrients by major organs that allow for the burning of fat during exercise or regulating the heart's contractile and electrical activity. Now they have found a new benefit of Kruppel-like Factor 15 (KLF15) -- keeping the body in metabolic balance.


From left: Peter Facchini, professor in biological sciences, Jill Hagel, research associate, and Scott Farrow, PhD student.
Many people who live in developing countries do not have access to the pain relief that comes from morphine or other analgesics. That's because opiates are primarily derived from the opium poppy plant (Papaver somniferum) and are dependent on the plant health and supply around the world.

Canadian and British researchers have discovered that chromosomes play an active role in animal cell division. This occurs at a precise stage - cytokinesis - when the cell splits into two new daughter cells. It was observed by a team of researchers including Gilles Hickson, an assistant professor at the University of Montreal's Department of Pathology and Cell Biology and researcher at the CHU Sainte-Justine Research Centre, his assistant Silvana Jananji, in collaboration with Nelio Rodrigues, a PhD student, and Sergey Lekomtsev, a postdoc, working in the group led by Buzz Baum of the MRC Laboratory for Molecular Cell Biology at University College London. Their findings were published today in Nature.


Australian researchers have identified a protein responsible for preserving the antibody-producing cells that lead to long-term immunity after infection or vaccination.
Melbourne researchers have identified a protein responsible for preserving the antibody-producing cells that lead to long-term immunity after infection or vaccination.


Left: Teosinte ear; right: corn ear; center: ear from the first generation hybrid of a cross between teosinte and corn.
If not for a single genetic mutation, each kernel on a juicy corn cob would be trapped inside a inedible casing as tough as a walnut shell. The mutation switches one amino acid for another at a specific position in a protein regulating formation of these shells in modern corn's wild ancestor, according to a study published in the July 2015 issue of GENETICS, a publication of the Genetics Society of America.


Fat cells with the R1788W ankyrin-B mutation (shown on the right) have enlarged lipid droplets. The green color highlights the sites of fat storage in mouse adipose cells.
Practically everyone gets fatter as they get older, but some people can blame their genes for the extra padding. Researchers have shown that two different mutations in a gene called ankyrin-B cause cells to suck up glucose faster than normal, fattening them up and eventually triggering the type of diabetes linked to obesity.


In germline cells PIWI proteins silence the RNA from jumping genes by cutting them in sequences of ~30 nucleotides that will become piRNAs.
DNA within reproductive cells is protected through a clever system of find and destroy: new research published in Cell Reports today lifts the veil on how this is done.


New research at Rice University shows how tumors create chaos in the development of neighboring blood vessels, causing them to grow too quickly and not form properly.
Rice University researchers have built a simulation to show how cancerous tumors manipulate blood-vessel growth for their own benefit.


This image shows TTP activation of neuronal gene expression.
The human organism contains hundreds of distinct cell types that often differ from their neighbours in shape and function. To acquire and maintain its characteristic features, each cell type must express a unique subset of genes. Neurons, the functional units of our brain, develop through differentiation of neuronal precursors, a process that depends on coordinated activation of hundreds and possibly thousands of neuron-specific genes.

Neurons are a limited commodity; each of us goes through life with essentially the same set we had at birth. But these cells, whose electrical signals drive our thoughts, perceptions, and actions, are anything but static. They change and adapt in response to experience throughout our lifetimes, a process better known as learning.


Chromosomes are seen as red, and kinetochores are green. (A-B) Bivalent appears normal (green arrows). (C) Bivalent begins to hyperstretch (orange arrows).
When egg cells form with an incorrect number of chromosomes--a problem that increases with age--the result is usually a miscarriage or a genetic disease such as Down syndrome. Now, researchers at the RIKEN Center for Developmental Biology in Japan have used a novel imaging technique to pinpoint a significant event that leads to these types of age-related chromosomal errors. Published in Nature Communications, the study shows that as egg cells mature in older women, paired copies of matching chromosomes often separate from each other at the wrong time, leading to early division of chromosomes and their incorrect segregation into mature egg cells.


Fluorescently labeled microtubules extend from the tips of the dendrites (top) into the axon and down into the giant synaptic terminal (bottom) of a single isolated goldfish retinal bipolar cell. A loop of microtubules encircles the inner plasma membrane of the terminal and anchors mitochondria.
Researchers have discovered a thick band of microtubules in certain neurons in the retina that they believe acts as a transport road for mitochondria that help provide energy required for visual processing. The findings appear in the July issue of The Journal of General Physiology.


Rodolfo Llinás of New York University School of Medicine at the MBL, Woods Hole, where he spends each summer as a Whitman Center iInvestigator.
Sleep seems simple enough, a state of rest and restoration that almost every vertebrate creature must enter regularly in order to survive. But the brain responds differently to stimuli when asleep than when awake, and it is not clear what brain changes happen during sleep. "It is the same brain, same neurons and similar requirements for oxygen and so on, so what is the difference between these two states?" asks Rodolfo Llinás, a professor of neuroscience at New York University School of Medicine and a Whitman Center Investigator at the Marine Biological Laboratory (MBL) in Woods Hole. In a recent paper, Choi, Yu, Lee, and Llinás announced that a specific calcium channel plays a crucial role in healthy sleep, a key step toward understanding both normal and abnormal waking brain functions.

The flu virus can be lethal. But what is often just as dangerous is the body's own reaction to the invader. This immune response consists of an inflammatory attack, meant to kill the virus. But if it gets too aggressive, this counterattack can end up harming the body's own tissues, causing damage that can lead to death.

Stanford University researchers studying how the brain controls movement in people with paralysis, related to their diagnosis of Lou Gehrig's disease, have found that groups of neurons work together, firing in complex rhythms to signal muscles about when and where to move.

Researchers at the University of Toronto have uncovered how Gram-negative bacteria -- a broad class of bugs that cause diseases ranging from gonorrhea to diarrhea and pneumonia -- can trigger a reaction from our immune system. This discovery could lead to new therapies and treatments that use the immune system to fight infections instead of antibiotics.


This is a Darling Downs funnel-web spider. Its venom evolved from an insulin-like hormone.
Funnel-web spider venom contains powerful neurotoxins that instantly paralyze prey (usually insects). Millions of years ago, however, this potent poison was just a hormone that helped ancestors of these spiders regulate sugar metabolism, similar to the role of insulin in humans. Surprisingly, this hormone's weaponization--described on June 11 in the journal Structure--occurred in arachnids as well as centipedes, but in different ways.


Period-lengthening/-shortening molecules can change the biological clock rhythm.
A team of chemists and biologists at the Institute of Transformative Bio-Molecules (ITbM), Nagoya University have succeeded in finding new molecules that change the circadian rhythm in mammals by applying synthetic chemistry methods, which makes use of highly selective metal catalysts.

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