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Regenerating Living Organs

Thursday April 10, 2014

University of Edinburgh researchers have accomplished something that has not been done before. They have successfully regenerated a living organ: the thymus. The thymus is a small glandular organ that produces specific immune cells called lymphocytes. The thymus normally deteriorates and shrinks with age. In the study, the researchers were able to reactivate the thymus in mice by increasing the levels of a specific protein. The protein, FOXN1, induced certain cells to rebuild the thymus.

According to researcher Dr. Rob Buckle, "This interesting study suggests that organ regeneration in a mammal can be directed by manipulation of a single protein, which is likely to have broad implications for other areas of regenerative biology." The researchers are hopeful that information gained from this study could be used to develop new treatments for individuals with dysfunctional immune systems.

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Invention of the 'Mini Heart'

Monday April 7, 2014

Human Heart
Image: Dream Designs FreeDigitalPhotos.net

George Washington University researchers have invented a new organ that aids in blood circulation. This organ functions as a 'mini heart' by helping blood to flow in veins with non-functioning valves. The 'mini heart' is a cuff of cardiac muscle cells that is able to contract to help pump blood through the venous portion of the cardiovascular system.

According to researcher Narine Sarvazyan, "We are suggesting, for the first time, to use stem cells to create, rather than just repair damaged organs. We can make a new heart outside of one's own heart, and by placing it in the lower extremities, significantly improve venous blood flow." The ability to create a new organ from a person's own adult stem cells represents an advancement in tissue engineering technology.

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Potential Treatment For Rare Cilia Disorders

Friday April 4, 2014

Cilia in Lung Trachea Epithelium
Credit: Louisa Howard

Duke University researchers have gained insight into how defective cilia cause a variety of different diseases. Cilia are organelles in some cells that aid in cellular locomotion and the detection of cell signaling molecules. Genetic defects in cilia have been linked to diseases and disorders such as blindness, heart and kidney disease, obesity, and learning difficulties.

According to researcher Nicholas Katsanis, "Understanding cilia dysfunction is important, because its association with so many disorders pose a significant societal and medical burden. And we look forward to seeing whether the insights we have learned in these studies are applicable to other disease." The researchers discovered that a malfunction in the cellular system responsible for removing damaged proteins plays a key role in cilia dysfunction. They are hopeful that this discovery may lead to a treatment for cilia disorders.

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Why Cells Don't Repair DNA Damage During Mitosis

Thursday April 3, 2014

When imposing repair on broken DNA strands during mitosis, some telomeres are seen to fuse together (one dot).
Image Credit: A. Orthwein/Durocher Lab

Researchers have solved the mystery of why cells shut off DNA repair processes during cell division. It is because a dividing cell does not recognize the difference between damaged DNA stands and telomeres. Telomeres are protective caps that are located on the ends of chromosomes. Repairing DNA during mitosis can lead to telomere fusion.

When the researchers altered cells so that they would repair DNA during mitosis, some of the telomeres fused together and the chromosomes were defective. According to lead author Dr. Alexandre Orthwein, "They (dividing cells) take the drastic action of turning off DNA repair, a process that is usually highly beneficial, to prevent chromosomes from fusing with each other by mistake." It is unclear as to why this happens, but the researchers state that this discovery provides new insights into the cell division process.

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Removal of Death Receptor Kills Cancer Cells

Wednesday March 26, 2014

Cancer Cells
Image Credit: Dr. Cecil Fox / National Cancer Institute

Researchers have discovered a way to kill cancer cells by eliminating a tumor suppressor protein. In normal cells, the FAS receptor (CD95) triggers a process called apoptosis when activated. Apoptosis or programmed cell death causes a cell to self-destruct. CD95 was thought to suppress tumors because it triggers apoptosis and prevents uncontrollable cell growth in normal cells. Northwestern University researchers found however, that when this receptor or its binding component (CD95 ligand) is removed from cancer cells, the cancer cells die. The absence of CD95 allows the cancer cells to increase in size, but they also produce toxic substances that damage their DNA.

According to lead researcher Marcus Peter, "The discovery seems counterintuitive because CD95 has previously been defined as a tumor suppressor. But when we removed it from cancer cells, rather than proliferate, they died. If CD95 was truly a tumor suppressor, its elimination would result in an enhanced growth and/or invasiveness of cancer cells." The study also found that normal cells without CD95 or the CD95 ligand are able to complete a normal life cycle. This suggests that unlike normal cells, cancer cells are dependent upon CD95 and CD95 ligand for survival.

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Muscle Cells From Stem Cells

Wednesday March 26, 2014

Muscle cells are stained green in this micrograph of cells grown from stem cells in a lab.
Image Credit: Masatoshi Suzuki

University of Wisconsin-Madison researchers have developed a new method for creating large quantities of skeletal muscle cells and muscle progenitor cells from human stem cells. The muscle cells can be generated from embryonic stem cells or from induced pluripotent stem (iPS) cells. IPS cells are genetically altered adult stem cells that are induced or prompted in a laboratory to take on the characteristics of embryonic stem cells.

According to researcher Masatoshi Suzuki, "Researchers have been looking for an easy way to efficiently differentiate stem cells into muscle cells that would be allowable in the clinic. The novelty of this technique is that it generates a larger number of muscle stem cells without using genetic modification, which is required by existing methods for making muscle cells." The newly developed method could prove to be a valuable tool in the study and treatment of muscular diseases such as amyotrophic lateral sclerosis (ALS) and muscular dystrophy.

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Honey Could Help Stop Resistant Bacteria

Wednesday March 19, 2014

Image Credit: Danilo Rizzuti

Honey could be the next weapon used in the fight against antibiotic resistance. Researchers state that honey has a variety of properties that actively kill bacteria. These properties include a high sugar concentration, hydrogen peroxide, acidity, and antioxidants.

According to lead researcher Susan M. Meschwitz, "The unique property of honey lies in its ability to fight infection on multiple levels, making it more difficult for bacteria to develop resistance." Several studies have shown that honey reduces the ability of bacteria to form bacterial biofilm, as well as their ability to cause disease.

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Mutation Produces Rare Blue Flowers

Monday March 17, 2014

Credit: Shed / Public Domain

Researchers have discovered that a gene mutation is responsible for the production of blue flowers in petunias. This mutation causes a cellular pump, which creates a highly acidic environment in cell structures called vacuoles, to malfunction. The reduced acidity causes flower petals that are normally red or violet to become blue. Unfortunately for the plant, blue flowers are less attractive to pollinators.

According to researcher Francesca Quattrocchio, "By studying the difference between blue and red flowers of petunias, we have discovered a novel type of transporter able to strongly acidify the inside of the vacuole." The researchers state that this discovery may help to develop processes for manipulating flower color in other plant species, and even change the taste of fruits, wines, and juices.

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What Are Mitochondria?

Thursday March 13, 2014

Image Credit: Louisa Howard

Mitochondria are the cell's power producers. They convert energy into forms that are usable by the cell. They are the sites of cellular respiration, which ultimately generates fuel for the cell's activities. The number of mitochondria in a cell can range from a few to several thousand, depending on the type of cell.

Mitochondria are commonly tubular or oblong shaped and are bounded by double membranes. The double membranes divide the mitochondrion into two distinct parts: the intermembrane space and the mitochondrial matrix.

Mitochondria are semiautonomous in that they can divide and grow to make more of themselves. They also have their own DNA and ribosomes. To learn more about mitochondria and other cellular components, visit The Cell.

Bacterium and Fungus Cause Severe Tooth Decay

Thursday March 13, 2014

This figure (a cross section of the biofilm) depicts S. mutans microcolonies (in green) together with C. albicans (in blue), all surrounded and enmeshed in an extracellular polysaccharides matrix (in red).
Credit: Hyun (Michel) Koo, University of Pennsylvania

Researchers have discovered that some forms of tooth decay result from an infection by both a bacterium and a fungus. The bacterium Streptococcus mutans and fungus Candida albicans work in conjunction to cause severe cavities, most often seen in preschool aged individuals. It was discovered that S. mutans produces a substance, extracellular polysaccharide (EPS), that allows the bacterium to stick to teeth. EPS is also used by C. albicans to produce a glue-like substance that enables the fungus to stick to teeth and to S. mutans.

According to researcher Hyun (Michel) Koo, "The combination of the two organisms led to a greatly enhanced production of the glue-like polymer, drastically boosting the ability of the bacterium and the fungus to colonize the teeth, increasing the bulk of the biofilms and the density of the infection." The two organisms working together led to greater plaque production and increased acid production. It is the acid that destroys tooth enamel, resulting in tooth decay.

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