Tag Archive: Cells


novelbacteri

LMU researchers have identified a yet unknown bacterial cell-cell communication system.

In nature, bacteria are no mavericks but live in close association with neighboring bacteria. They have evolved specific cell-cell communication systems that allow them to detect the presence of others and even to build up cooperative networks. LMU microbiologist PD Dr. Ralf Heermann and Professor Helge Bode of the Goethe-University in Frankfurt have just reported the discovery of a previously unknown bacterial “language”. Their findings are detailed in the latest issue of the journal Nature Chemical Biology. “Our results demonstrate that bacterial communication is much more complex than has been assumed to date,” Heermann says.

The bacterial communication system that is currently best understood uses N-acylhomoserine lactones (AHLs) as signals. These compounds are made by enzymes that belong to the group of LuxI-family synthases. Transmitting cells secrete the signal and neighboring cells recognize the concentration via a LuxR-type receptor. Signal perception changes the pattern of gene expression in the receiving cells, which results in alterations in their functional properties or behavior. However, many bacteria have LuxR receptors but lack any LuxI homolog, so that they cannot produce AHLs. These receptors are referred to as LuxR solos.

Continue reading

The ability of cells to move and change shape is significant in many biological processes. White blood corpuscles gather at “hotspots” like infections and inflammations. Stem cells in the embryo move off in different directions to make the organs of the body. One unwanted movement is the movement of tumour cells, which lead to cancer metastasis.

Cells have a clear leading and trailing edge and move by a broad, thin membrane protrusion shooting out in front while the rest of the cell follows it. Small, finger-like filopodia (the green parts of the human renal cell pictured at left) can also project out from the protrusion, probably a type of cellular antenna that senses the chemical environment – bacterial secretions, for example.

But what governs this ability to move? Water, say the Linköping research team, who set out their hypothesis in the scientific journal PLOS One.

For a cell to be able to initiate a movement there needs to be a complex interaction between the outer cell membrane and the cytoskeleton on the inside. One of the most important components is the protein actin, which has the ability to create dynamic fibres that can grow at one end and recede at the other. The current thinking is that, in this way, the membrane can push out and create the protrusions. But experiments and modelling have led the LiU researchers to another picture of the mechanism.

“We looked at how cells create the membrane protrusions they need in order to be able to move. We showed that the water flow out of and into the cells through water channels, or aquaporins, in the cell membrane is important,” says Thommie Karlsson, researcher in medical microbiology and principal author of the article.

Continue reading

OMG Microscope Photos

Back in 2011, GE unveiled DeltaVision OMX Blaze, a state-of-the art microscope that uses a combination of optics and powerful computer algorithms. Using a technique called 3D structured illumination microscopy (SIM), OMX can see objects as small as 100 nanometers across and more than doubles the resolution in all three dimensions. Here are some of the most mind blowing super-resolution images taken by the microscope to date.

Metaphase epithelial cell in metaphase stained for microtubules (red), kinetochores (green) and DNA (blue). 

Cancer: Interphase human cervical cancer cell stained for microtubules (green), pericentrin centrosome protein (red) and DNA (blue).

Immunology and infection: CACO-2 intestinal epithelial cells stained to label the apical actin cytoskeleton.

Cancer: Mitotic spindle in a PTK1 cell stained for tubulin (green) and Ncd80 (red).

Continue reading

zombie-cells.jpg

In news that just makes me want to throw my hands up and tell the lord to take me now, scientists have created “zombie” cells in the laboratory that can outperform living ones. I don’t even know what that means but I just taped a knife to a mop handle to fend off whatever hellspawn comes out of this.

A team at Sandia National Laboratories and the University of New Mexico have innovated a technique whereby mammalian cells are coated with silica to form a near-perfect replicas.
The silica replicants can survive greater pressures and temperatures than flesh, and perform many functions better than the original cells did when alive.

By painting the cells with silicic acid in a petri dish, the acid embalms the organic matter in the cell down to the nanometer level.

Heating the silica to around 400C evaporates the protein in the cell, but leaves the silica as a three-dimensional replica of the “formerly living being”, Hess said.

“Our zombie cells bridge chemistry and biology to create forms that not only near-perfectly resemble their past selves, but can do future work,” he said, terrifyingly.

Gotta start watching The Walking Dead!

Synthetic biologists have developed DNA modules that perform logic operations in living cells. These ‘genetic circuits’ could be used to track key moments in a cell’s life or, at the flick of a chemical switch, change a cell’s fate, the researchers say. Their results are described this week in Nature Biotechnology.

Synthetic biology seeks to bring concepts from electronic engineering to cell biology, treating gene functions as components in a circuit. To that end, researchers at the Massachusetts Institute of Technology (MIT) in Cambridge have devised a set of simple genetic modules that respond to inputs much like the Boolean logic gates used in computers.

“These developments will more readily enable one to create programmable cells with decision-making capabilities for a variety of applications,” says James Collins, a synthetic biologist at Boston University in Massachusetts who was not involved in the study.

Collins developed the genetic ‘toggle switch’ that helped to kick-start the field of synthetic biology more than a decade ago. A wide range of computational circuits for cells have been developed since, including a simple counter that Collins and his team devised in 2009.

But “to make this a really rigorous engineering discipline, we need to move towards frameworks that allow you to program cells in a more scalable fashion,” says Timothy Lu, a synthetic biologist at MIT who led the latest research. “We wanted to show you can assemble a bunch of simple parts in a very easy fashion to give you many types of logical functions.”

Continue reading

Camouflaged nanoparticles (yellow) cloaked in the membranes of white blood cells rest on the surface of an immune system cell (phagocyte, blue) without being recognized, ingested, and destroyed

By cloaking nanoparticles in the membranes of white blood cells, scientists at The Methodist Hospital Research Institute may have found a way to prevent the body from recognizing and destroying them before they deliver their drug payloads. The group describes its “LeukoLike Vectors”, or LLVs, in the January issue of Nature Nanotechnology.

“Our goal was to make a particle that is camouflaged within our bodies and escapes the surveillance of the immune system to reach its target undiscovered,” said Department of Medicine Co-Chair Ennio Tasciotti, Ph.D., the study’s principal investigator. “We accomplished this with the lipids and proteins present on the membrane of the very same cells of the immune system. We transferred the cell membranes to the surfaces of the particles and the result is that the body now recognizes these particles as its own and does not readily remove them.”

Nanoparticles can deliver different types of drugs to specific cell types, for example, chemotherapy to cancer cells. But for all the benefits they offer and to get to where they need to go and deliver the needed drug, nanoparticles must somehow evade the body’s immune system that recognizes them as intruders. The ability of the body’s defenses to destroy nanoparticles is a major barrier to the use of nanotechnology in medicine. Systemically administered nanoparticles are captured and removed from the body within few minutes. With the membrane coating, they can survive for hours unharmed.

Continue reading

Using a super-resolution fluorescent microscope, medical scientists are a step closer to understanding why and how human immune cells decide to activate or not, thus enabling or preventing disease taking hold in the body.

Professor Katharina Gaus and her team at the Centre for Vascular Research based at UNSW’s Lowy Cancer Research Centre used some of the most advanced super-resolution optical microscope technology available anywhere in the world to see changes in individual proteins in T-cells – the workhorse of our immune system. “Every day, every second, our immune cells make decisions to activate or not activate,” Professor Gaus says. “Every time they make a decision, the outcome is life or death.” In a paper published in Nature Immunology, Professor Gaus and her team show, for the first time, how the molecule protein ‘kinase’ is distributed across membranes – opening and closing like the Pacman in the 1980s computer game. “The kinase we examined is called Lck and is essential for the activation of T-cells but is also involved in many other cell signalling processes,” Professor Gaus says. “Understanding how kinase activity is controlled is the key to knowing what goes wrong in many diseases including immune disorders and cancer.”

Continue reading

Andemariam Beyene sat by the hospital window, the low Arctic sun on his face, and talked about the time he thought he would die.

Two and a half years ago doctors in Iceland, where Mr. Beyene was studying to be an engineer, discovered a golf-ball-size tumor growing into his windpipe. Despite surgery and radiation, it kept growing. In the spring of 2011, when Mr. Beyene came to Sweden to see another doctor, he was practically out of options. “I was almost dead,” he said. “There was suffering. A lot of suffering.”

But the doctor, Paolo Macchiarini, at the Karolinska Institute here, had a radical idea. He wanted to make Mr. Beyene a new windpipe, out of plastic and his own cells.

Implanting such a “bioartificial” organ would be a first-of-its-kind procedure for the field of regenerative medicine, which for decades has been promising a future of ready-made replacement organs — livers, kidneys, even hearts — built in the laboratory.

For the most part that future has remained a science-fiction fantasy. Now, however, researchers like Dr. Macchiarini are building organs with a different approach, using the body’s cells and letting the body itself do most of the work.

“The human body is so beautiful, I’m convinced we must use it in the most proper way,” said Dr. Macchiarini, a surgeon who runs a laboratory that is a leader in the field, also called tissue engineering.

So far, only a few organs have been made and transplanted, and they are relatively simple, hollow ones — like bladders and Mr. Beyene’s windpipe, which was implanted in June 2011. But scientists around the world are using similar techniques with the goal of building more complex organs. At Wake Forest University in North Carolina, for example, where the bladders were developed, researchers are working on kidneys, livers and more. Labs in China and the Netherlands are among many working on blood vessels.

Continue reading

Sometimes stepping back and looking at the big picture can lend new clarity to an ongoing debate. In this case, it took the distant perspective of astrobiologists to reckon the origins of cancer.

The astrobiologists, working with oncologists in the US, have suggested that cancer resembles ancient forms of life that flourished between 600 million and 1 billion years ago.

The genes that controlled the behaviour of these early multicellular organisms still reside within our own cells, managed by more recent genes that keep them in check.

It’s when these newer controlling genes fail that the older mechanisms take over, and the cell reverts to its earlier behaviours and grows out of control.

Continue reading

University of Florida researchers have moved a step closer to treating diseases on a cellular level by creating a tiny particle that can be programmed to shut down the genetic production line that cranks out disease-related proteins. In laboratory tests, these newly created “nanorobots” all but eradicated hepatitis C virus infection. The programmable nature of the particle makes it potentially useful against diseases such as cancer and other viral infections. The research effort, led by Y. Charles Cao, a UF associate professor of chemistry, and Dr. Chen Liu, a professor of pathology and endowed chair in gastrointestinal and liver research in the UF College of Medicine, is described online this week in the Proceedings of the National Academy of Sciences. “This is a novel technology that may have broad application because it can target essentially any gene we want,” Liu said. “This opens the door to new fields so we can test many other things. We’re excited about it.”

During the past five decades, nanoparticles — particles so small that tens of thousands of them can fit on the head of a pin — have emerged as a viable foundation for new ways to diagnose, monitor and treat disease. Nanoparticle-based technologies are already in use in medical settings, such as in genetic testing and for pinpointing genetic markers of disease. And several related therapies are at varying stages of clinical trial. The Holy Grail of nanotherapy is an agent so exquisitely selective that it enters only diseased cells, targets only the specified disease process within those cells and leaves healthy cells unharmed.

Continue reading

Scientists have invented artificial pores as small as the ones in your cells—something unimaginable until now. These sub-nanometer synthetic pores are so tiny that they can distinguish between ions of different substances, just like a real cell. It’s an amazing engineering feat. Once they tune them to detect different substances, researchers claim that this seemingly miraculous matter would be able to do truly incredible things, from “purifying water to kill tumors and diseases by regulating the substances inside of cells.”

The scientists used the Advanced Photon Source at Argonne National Laboratory to create the pores, gluing donut-shaped molecules—called rigid macrocycles—on top of each other using hydrogen bonding. According to one of the senior authors of the study, University of Nebraska-Lincoln Ameritas University’s chemistry professor Xiao Cheng Zeng—”this nanotube can be viewed as a stack of many, many rings. The rings come together through a process called self-assembly, and it’s very precise. It’s the first synthetic nanotube that has a very uniform diameter.” They are about 8.8 angstroms thick, just one tenth of a nanometer.

They are now capable of passing potassium ions and water, but not other ions, like sodium and lithium ions. Basically, this means that you could pass salt water through a fabric made of this wonder material and make it drinkable—instantly. Lead researcher Dr. Bing Gong—a chemistry professor at University of Buffalo—says that “the idea for this research originated from the biological world, from our hope to mimic biological structures, and we were thrilled by the result. We have created the first quantitatively confirmed synthetic water channel. Few synthetic pores are so highly selective.” Gong says that they now have to experiment with the pores’ structure to find out how the materials are transported through the pores and tune it to select which substances they want to filter and which ones they want to let through. If they are successful, this material has an incredible potential to change almost everything.

The Birth of Brain Cells

This might look like a distant web of galaxies captured by a powerful telescope, but it’s actually a microscopic image of a newborn nerve cell. The human brain contains more cells than there are stars in our galaxy, and the most important cells are neurons, which are nerve cells responsible for transmitting and processing electro-chemical signals at up to 320 km/h. This chemical signalling occurs through synapses—specialised connections with other cells, like wires in a computer. Each cell can receive input from thousands of others, so a typical neuron can have up to ten thousand synapses—i.e., can communicate with up to ten thousand other neurons, muscle cells, and glands. Estimates suggest that adult humans have approximately 100 billion neurons in their brain, but unlike most cells, neurons don’t undergo cell division, so if they’re damaged they don’t grow back—except, apparently, in the hippocampus (associated with memory) and the olfactory bulb (associated with sense of smell). The process by which this occurs is unclear, and this image was taken during a project to determine how neurons are born—it actually depicts newborn nerve cells in an adult mouse’s brain.

The Inner Life of the Cell

Harvard University selected XVIVO to develop an animation that would take their cellular biology students on a journey through the microscopic world of a cell, illustrating mechanisms that allow a white blood cell to sense its surroundings and respond to an external stimulus.

Your body will assemble 30 million new cells in the time it takes to read this. Each has the complexity of a medium-sized city.

Scientist say they have managed to turn patients’ own skin cells into healthy heart muscle in the lab. Ultimately they hope this stem cell therapy could be used to treat heart failure patients. As the transplanted cells are from the individual patient this could avoid the problem of tissue rejection, they told the European Heart Journal. Early tests in animals proved promising but the experimental treatment is still years from being used in people.

Experts have increasingly been using stem cells to treat a variety of heart problems and other conditions like diabetes, Parkinsons disease or Alzheimer’s. Stem cells are important because they have the ability to become different cell types, and scientists are working on developing ways to get them to repair or regenerate damaged organs or tissues. More than 750,000 people in the UK have heart failure. It means the heart is not pumping blood around the body as well as it used to.

Researchers are looking at ways of fixing the damaged heart muscle. In the latest study, the team in Israel took skin cells from two men with heart failure and mixed the cells up with a cocktail of genes and chemicals in the lab to create the stem cell treatment. The cells that they created were identical to healthy heart muscle cells. When these beating cells were transplanted into a rat, they started to make connections with the surrounding heart tissue.

Continue reading

Chemists have created artificial self-assembling cell membranes that could help shed light...

The cell membrane is one of the most important components of a cell because it separates the interior from the environment and controls the movement of substances in and out of the cell. In a move that brings mankind another step closer to being able to create artificial life forms from scratch, chemists from the University of California, San Diego (UCSD), and Harvard University have created artificial self-assembling cell membranes using a novel chemical reaction. The chemists hope their creation will help shed light on the origins of life.

As the basic structural and functional unit of all known living organisms, the cell is the smallest unit of life that is classified as a living thing. Although there are various theories – meteorites, deep-sea vents, lightning – there is still no scientific consensus regarding the origin of the first cell.

“We don’t understand this really fundamental step in our existence, which is how non-living matter went to living matter,” said Neal Devaraj, assistant professor of chemistry at UCSD. “So this is a really ripe area to try to understand what knowledge we lack about how that transition might have occurred. That could teach us a lot – even the basic chemical, biological principles that are necessary for life.”

Continue reading

A pore cluster

Scientists at The University of Nottingham are leading an ambitious research project to develop an in vivo biological cell-equivalent of a computer operating system.
The success of the project to create a ‘re-programmable cell’ could revolutionise synthetic biology and would pave the way for scientists to create completely new and useful forms of life using a relatively hassle-free approach.Professor Natalio Krasnogor of the University’s School of Computer Science, who leads the Interdisciplinary Computing and Complex Systems Research Group, said: “We are looking at creating a cell’s equivalent to a computer operating system in such a way that a given group of cells could be seamlessly re-programmed to perform any function without needing to modifying its hardware.”

Follow

Get every new post delivered to your Inbox.

Join 262 other followers

%d bloggers like this: