Tag Archives: cell

How Cells Age

A new study by Harvard Medical School researchers reveals that the biochemical mechanism that makes yeast grow old has a surprising parallel in mice, suggesting it may be a universal cause of aging in all organisms.
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In young organisms, SIRT1 effectively doubles as a gene-expression regulator and a DNA repairer. But when DNA damage accumulates—as it does with age—SIRT1 becomes too busy fixing broken DNA to keep the expression of hundreds of genes in check. This process is so similar to what happens in aging yeast that its discoverers believe it may represent a universal mechanism of aging.

Harvard researchers gain new insight into aging

Aging may be a case of neglect — an absentee landlord at the cellular level that allows gene activity to go awry, according to a study published today.

Scientists have long known that aging causes gene expression to change, and DNA damage to accumulate. But now, research led by Harvard Medical School scientists explains the connection between the two processes in mammals.

The paper, published in the journal Cell, found that a multi-tasking protein called SIRT1 that normally acts as guardian of the genome gets dragged away to DNA fix-it jobs. When the protein abandons its normal post to work as a genetic handyman, order unravels elsewhere in the cell. Genes that are normally under its careful watch begin to flip on.

“What this paper actually implies is that aspects of aging may be reversible,” said David Sinclair, a Harvard Medical School biologist who led the research. “It sounds crazy, but in principle it should be possible to restore the youthful set of genes, the patterns that are on and off.”

The study is just the latest to draw yet more attention to sirtuins, proteins involved in the aging process

Aging is fascinating. By and large people just accept it. We see it happen to those all around us, without exception. But what causes biological aging? It is an interesting area of research.

Single-Celled Giant Provides New Early-Evolution Perspective

Discovery of Giant Roaming Deep Sea Protist Provides New Perspective on Animal Evolution
Biologist Mikhail “Misha” Matz and his colleagues recently discovered the grape-sized protists and their complex tracks on the ocean floor near the Bahamas. DNA analysis confirmed that the giant protist found by Matz and his colleagues in the Bahamas is Gromia sphaerica, a species previously known only from the Arabian Sea.

Matz says the protists probably move by sending leg-like extensions, called pseudopodia, out of their cells in all directions. The pseudopodia then grab onto mud in one direction and the organism rolls that way, leaving a track. Hr says the giant protists’ bubble-like body design is probably one of the planet’s oldest macroscopic body designs, which may have existed for 1.8 billion years.

“I personally think now that the whole Precambrian may have been exclusively the reign of protists,” says Matz. “Our observations open up this possible way of interpreting the Precambrian fossil record.”

He says the appearance of all the animal body plans during the Cambrian explosion might not just be an artifact of the fossil record. There are likely other mechanisms that explain the burst-like origin of diverse multicellular life forms.

Single-Celled Giant Upends Early Evolution

Slowly rolling across the ocean floor, a humble single-celled creature is poised to revolutionize our understanding of how complex life evolved on Earth.

A distant relative of microscopic amoebas, the grape-sized Gromia sphaerica was discovered once before, lying motionless at the bottom of the Arabian Sea. But when Mikhail Matz of the University of Texas at Austin and a group of researchers stumbled across a group of G. sphaerica off the coast of the Bahamas, the creatures were leaving trails behind them up to 50 centimeters (20 inches) long in the mud.

The trouble is, single-celled critters aren’t supposed to be able to leave trails. The oldest fossils of animal trails, called ‘trace fossils’, date to around 580 million years ago, and paleontologists always figured they must have been made by multicellular animals with complex, symmetrical bodies.

Exploring the Signaling Pathways of Cells

New probe may help untangle cells’ signaling pathways

MIT researchers have designed a new type of probe that can image thousands of interactions between proteins inside a living cell, giving them a tool to untangle the web of signaling pathways that control most of a cell’s activities.

“We can use this to identify new protein partners or to characterize existing interactions. We can identify what signaling pathway the proteins are involved in and during which phase of the cell cycle the interaction occurs,” said Alice Ting, the Pfizer-Laubach Career Development Assistant Professor of Chemistry and senior author of a paper describing the probe published online June 27 by the Journal of the American Chemical Society.

The new technique allows researchers to tag proteins with probes that link together like puzzle pieces if the proteins interact inside a cell. The probes are derived from an enzyme and its peptide substrate. If the probe-linked proteins interact, the enzyme and substrate also interact, which can be easily detected.

To create the probes, the researchers used the enzyme biotin ligase and its target, a 12-amino-acid peptide.

Cell Signals Webcast

Very cool animation, by Cold Spring Harbor Laboratory and Interactive Knowledge, of the working of the inner workings of our bodies as they react to a cut. If you want to get right to the science, skip the first minute. Providing these types of educational animations is a great way for educational institutions to take advantage of technology to achieve their mission in ways not possible before.

It is annoying how many of those “educational” institutions don’t provide such educational material online (and even take material offline that was online). Have they become more focused on thinking and operating the way they did in 1970 than promoting science education? It is a shame some “educational” institutions have instead become focused on looking backward. I will try to promote those organizations that are providing online science education.

Cloned Immune Cells Clear Patient’s Cancer

Cloned immune cells cleared patient’s cancer

A patient whose skin cancer had spread throughout his body has been given the all-clear after being injected with billions of his own immune cells. Tests revealed that the 52-year-old man’s tumours, which spread from his skin to his lung and groin, vanished within two months of having the treatment, and had not returned two years later.

Doctors attempted the experimental therapy as part of a clinical trial after the man’s cancer failed to respond to conventional treatments.

The man is the first to benefit from the new technique, which uses cloning to produce billions of copies of a patient’s immune cells. When they are injected into the body they attack the cancer and force it into remission.

There are many more wonderful announcements than wonderful solutions that live up to the hope provided by the announcement. Still this is one in the long line of potentially wonderful treatments. If it turns out to be successful the whole world will benefit which is an example of why I am thankful so many countries are investing in science and technology.

Funding Medical Research

Cheap, ‘safe’ drug kills most cancers

It sounds almost too good to be true: a cheap and simple drug that kills almost all cancers by switching off their “immortality”. The drug, dichloroacetate (DCA), has already been used for years to treat rare metabolic disorders and so is known to be relatively safe. It also has no patent, meaning it could be manufactured for a fraction of the cost of newly developed drugs.

Evangelos Michelakis of the University of Alberta in Edmonton, Canada, and his colleagues tested DCA on human cells cultured outside the body and found that it killed lung, breast and brain cancer cells, but not healthy cells. Tumours in rats deliberately infected with human cancer also shrank drastically when they were fed DCA-laced water for several weeks.

DCA attacks a unique feature of cancer cells: the fact that they make their energy throughout the main body of the cell, rather than in distinct organelles called mitochondria. This process, called glycolysis, is inefficient and uses up vast amounts of sugar.

Until now it had been assumed that cancer cells used glycolysis because their mitochondria were irreparably damaged. However, Michelakis’s experiments prove this is not the case, because DCA reawakened the mitochondria in cancer cells. The cells then withered and died

The University of Alberta is raising funds to further the research. Some look at this and indite a funding system that does not support research for human health unless there is profit to be made. Much of the blame seems to go to profit focused drug companies. I can see room for some criticism. But really I think the criticism is misplaced.

The organizations for which curing cancer is the partial aim (rather than making money) say government (partial aim or public health…), public universities (partial aim of science research or medical research…), foundations, cancer societies, private universities… should fund such efforts, if they have merit. Universities have huge research budgets. Unfortunately many see profit as their objective and research as the means to the objective (based on their actions not their claims). These entities with supposedly noble purposes are the entities I blame most, not profit focused companies (though yes, if they claim an aim of health care they I would blame them too).

Now I don’t know what category this particular research falls into. Extremely promising or a decent risk that might work just like hundreds or thousands of other possibilities. But lets look at several possibilities. Some others thoughts on where it falls: Dichloroacetate to enter clinical trials in cancer patients, from a previous post here – Not a Cancer Cure Yet, The dichloroacetate (DCA) cancer kerfuffle, CBC’s ‘The Current’ on dichloroacetate (DCA), Dichloroacetate (DCA) Phase II Trial To Begin (“Like hundreds (if not, thousands) of compounds being tested to treat cancer, DCA was shown by Michelakis’ group earlier this year to slow the growth of human lung tumors in a preclinical rodent model.”).
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Molecular Bioengineering and Dynamical Models of Cells

Study Maps Life in Extreme Environments, Creating Potential for Molecular Bioengineering and Dynamical Models of Cells

The researchers focused on a little studied organism that can survive high salt, radiation, and other stresses that would be deadly to most other organisms. By focusing on such an organism the researchers were able to show definitively that they could understand and model the circuit controlling the cell directly from experiments designed to measure all genes in the genome simultaneously. These are called systems-biology experiments. This scholarship is part of a new scientific field, systems biology, which examines how genes influence each other via extremely large networks of interaction and how these networks respond to stimuli, adapting over time to new environments and cell states.
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“This is also a good model to explain how, in general, cells make stable decisions as they move through time scales,” added Bonneau, who is part of an NYU research group that handled the analysis of this genome. “If you want to understand how cells respond to their environments, the model offers a clearer window than previously existed for this domain of life.” The collaboration between Baliga’s and Bonneau’s research groups represents a type of partnership becoming more essential to biological and biomedical research: biologists and computer scientists teaming up to design experiments and analysis that synergize to decipher living systems, resulting in ever more complex and accurate models of the cell.

People Have More Bacterial Cells than Human Cells

Humans Carry More Bacterial Cells than Human Ones

All the bacteria living inside you would fill a half-gallon jug; there are 10 times more bacterial cells in your body than human cells
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The infestation begins at birth: Babies ingest mouthfuls of bacteria during birthing and pick up plenty more from their mother’s skin and milk—during breast-feeding, the mammary glands become colonized with bacteria. “Our interaction with our mother is the biggest burst of microbes that we get,”
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there are estimated to be more than 500 species living at any one time in an adult intestine, the majority belong to two phyla, the Firmicutes (which include Streptococcus, Clostridium and Staphylococcus), and the Bacteroidetes (which include Flavobacterium).
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probiotics – dietary supplements containing potentially beneficial microbes – have been shown to boost immunity. Not only do gut bacteria “help protect against other disease-causing bacteria that might come from your food and water,” Huffnagle says, “they truly represent another arm of the immune system.”
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But the bacterial body has made another contribution to our humanity – genes. Soon after the Human Genome Project published its preliminary results in 2001, a group of scientists announced that a handful of human genes – the consensus today is around 40 – appear to be bacterial in origin.

How cool is science? Very, I think 🙂

Using Bacteria to Carry Nanoparticles Into Cells

Bacteria ferry nanoparticles into cells for early diagnosis, treatment

Researchers at Purdue University have shown that common bacteria can deliver a valuable cargo of “smart nanoparticles” into a cell to precisely position sensors, drugs or DNA for the early diagnosis and treatment of various diseases. The approach represents a potential way to overcome hurdles in delivering cargo to the interiors of cells, where they could be used as an alterative technology for gene therapy, said Rashid Bashir, a researcher at Purdue’s Birck Nanotechnology Center.

The researchers attached nanoparticles to the outside of bacteria and linked DNA to the nanoparticles. Then the nanoparticle-laden bacteria transported the DNA to the nuclei of cells, causing the cells to produce a fluorescent protein that glowed green. The same method could be used to deliver drugs, genes or other cargo into cells.

“The released cargo is designed to be transported to different locations in the cells to carry out disease detection and treatment simultaneously,” said Bashir, a professor in the Weldon School of Biomedical Engineering and the School of Electrical and Computer Engineering. “Because the bacteria and nanoparticle material can be selected from many choices, this is a delivery system that can be tailored to the characteristics of the receiving cells. It can deliver diagnostic or therapeutic cargo effectively for a wide range of needs.”

Harmless strains of bacteria could be used as vehicles, harnessing bacteria’s natural ability to penetrate cells and their nuclei, Bashir said. “For gene therapy, a big obstacle has been finding ways to transport the therapeutic DNA molecule through the nuclear membrane and into the nucleus,” he said. “Only when it is in the nucleus can the DNA produce proteins that perform specific functions and correct genetic disease conditions.”
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The Inner Life of a Cell – Animation

The Inner Life of a Cell, an eight-minute animation created for Harvard biology students… illustrates unseen molecular mechanisms and the ones they trigger, specifically how white blood cells sense and respond to their surroundings and external stimuli.

The online video is beautiful, see – Cellular Visions: The Inner Life of a Cell. Update: Unfortunately the webcast links on that page are not working but you can see a longer version than was available via: Inner Life of a Cell – Full Version.
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