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Archive - Apr 9, 2015

Indigenous Bacteria Regulate Serotonin Synthesis in Gut

Although serotonin (image)is well known as a brain neurotransmitter, it is estimated that 90 percent of the body's serotonin is made in the digestive tract. In fact, altered levels of this peripheral serotonin have been linked to diseases such as irritable bowel syndrome, cardiovascular disease, and osteoporosis. New research at Caltech, published in the April 9 issue of the journal Cell, shows that certain bacteria in the gut are important for the production of peripheral serotonin. The title of the article is “Indigenous Bacteria from the Gut Microbiota Regulate Host Serotonin Biosynthesis.” The Cell article is accompanied by a Cell Preview entitled “Gut Microbiota: The Link to Your Second Brain.” "More and more studies are showing that mice or other model organisms with changes in their gut microbes exhibit altered behaviors," explains Dr. Elaine Hsiao, Research Assistant Professor of Biology and Biological Engineering and senior author of the study. "We are interested in how microbes communicate with the nervous system. To start, we explored the idea that normal gut microbes could influence levels of neurotransmitters in their hosts." Peripheral serotonin is produced in the digestive tract by enterochromaffin (EC) cells and also by particular types of immune cells and neurons. Dr. Hsiao and her colleagues first wanted to know if gut microbes have any effect on serotonin production in the gut and, if so, in which types of cells. They began by measuring peripheral serotonin levels in mice with normal populations of gut bacteria and also in germ-free mice that lack these resident microbes. The researchers found that the EC cells from germ-free mice produced approximately 60 percent less serotonin than did their peers with conventional bacterial colonies.

Horizontal Transmission of Clonal Cancer Found in Soft-Shelled Clams; Only Third Such Example in Nature; Cover Article in Cell

Outbreaks of leukemia that have devastated some populations of soft-shell clams along the east coast of North America for decades can be explained by the spread of cancerous tumor cells from one clam to another. Researchers call the discovery, which was featured as the cover story in the April 9, 2015 issue of Cell, "beyond surprising." The article is titled “Horizontal Transmission of Clonal Cancer Cells Causes Leukemia in Soft-Shell Clam.” "The evidence indicates that the tumor cells themselves are contagious--that the cells can spread from one animal to another in the ocean," said Dr. Stephen Goff of the Howard Hughes Medical Institute and Columbia University. "We know this must be true because the genotypes of the tumor cells do not match those of the host animals that acquire the disease, but instead all derive from a single lineage of tumor cells." In other words, the cancer that has killed so many clams all trace to one incidence of disease. The cancer originated in some unfortunate clam somewhere and has persisted ever since as those cancerous cells divide, break free, and make their way to other clams. Only two other examples of transmissible cancer are known in the wild. These cancers include the canine transmissible venereal tumor, transmitted by sexual contact, and the Tasmanian devil facial tumor disease, transmitted through biting. In early studies of the cancer in clams, Dr. Goff and his colleagues found that a particular sequence of DNA (which they named Steamer) was found at incredibly high levels in leukemic versus normal clam cells. While normal cells contain only two to five copies of Steamer, cancerous clam cells can have 150 copies. The researchers at first thought that this difference was the result of a genetic amplification process occurring within each individual clam.

Next-Generation Optogenetics Program Launched in Germany

Optogenetics is a new field of research that introduces light-sensitive proteins into cells in a genetically targeted manner, for example, to obtain information on signalling pathways and the function of neurons in a living organism. A new priority program supported by the German Research Foundation (DFG) under the auspices of Goethe University has now set itself the goal of developing the next generation of optogenetic tools and expanding their application both in basic research and also for medical purposes. DFG will provide six million Euros in funding for the program over the next three years. "We see our role as a pathfinder, to build a scientific network for optogenetics in Germany," says Professor Alexander Gottschalk, spokesperson for the priority program, which is titled "Next Generation Optogenetics: Tool Development and Applications." After an application phase in the autumn of 2015, between 30 and 40 scientists from different universities will become involved; primarily biophysicists, cell biologists, chemists, medical scientists, and "photo-biologists." These are the types of specialists who will search for new, light-sensitive proteins, which will be introduced into cells and act like light switches to turn cellular processes on and off. "Optogenetics already has many applications in basic research, but as a technology it is still in its infancy," explains Professor Gottschalk. In order to achieve more widespread use of optogenetics in cell biology and neurobiology, the researchers want to develop new optogenetic tools. These will have higher light sensitivity, clarify the processes within individual cells and between different cells, and ultimately also be tested in animal models.

Low-Temperature Plasmas Show Promise As Novel Treatment for Early-Stage Prostate Cancer; Clinical Application Not Likely for 10 or More Years, However

Scientists at the University of York in the UK have discovered a potential new treatment for prostate cancer using low-temperature plasmas (LTPs). Published online on April 2, 2015 in an open-access article in the British Journal of Cancer (BJC), the study represents the first time LTPs have been applied on cells grown directly from patient tissue samples. The article title is “Low-Temperature Plasma Treatment Induces DNA Damage Leading to Necrotic Cell Death in Primary Prostate Epithelial Cells.” The study is the result of a unique collaboration between the York Plasma Institute in the Department of Physics and the Cancer Research Unit (CRU) in York's Department of Biology. Taking both healthy prostate cells and prostate cancer tissue cells from a single patient, the study allowed for direct comparison of the effectiveness of the treatment. Scientists discovered that LTPs may be a potential option for treatment of patients with organ-confined prostate cancer, and a viable, more cost-effective alternative to current radiotherapy and photodynamic therapy (PDT) treatments. Low-temperature plasmas are formed by applying a high electric field across a gas using an electrode, which breaks down the gas to form plasma. This creates a complex, unique reactive environment containing high concentrations of reactive oxygen and nitrogen species (RONS). Operated at atmospheric pressure and around room temperature, the delivery of RONS, when transferred through plasma to a target source, is a key mediator of oxidative damage and cell death in biological systems. The way cell death occurs when using LTP treatment is different from other therapies. The active agents in the LTP break up DNA and destroy cells by necrosis, where cell membranes are ruptured, resulting in cell death.

Delicate Magnolia Scent Activates Putative Human Pheromone Receptor

The question as to whether or not humans can communicate via pheromones in the same way as animals is under debate. Cell physiologists at the Ruhr-Universität Bochum, however, have recently demonstrated that the odorous substance Hedione activates the putative pheromone receptor VN1R1, which occurs in the human olfactory epithelium. Together with colleagues from Dresden, the Bochum-based researchers showed that the scent of Hedione generates sex-specific activation patters in the brain, which do not occur with traditional fragrances. "These results constitute compelling evidence that a pheromone effect different from normal olfactory perception indeed exists in humans," says scent researcher Professor Dr. Hanns Hatt. The team published the results online on March 19, 2015 in the Journal NeuroImage. Using genetic-analysis approaches, the researchers from Bochum confirmed the pheromone receptor's existence in human olfactory mucosa. Subsequently, they transferred the genetic code for the receptor into cell cultures and, using these cells, demonstrated that Hedione activates the receptor. Hedione - derived from the Greek word "hedone," for fun, pleasure, lust; has a pleasant fresh jasmine-magnolia scent and is utilized in many perfumes. It is also called the scent of success. Together with the team headed by Professor Dr. Thomas Hummel from the University Hospital Dresden, the group from Bochum analyzed what happens in the brain when a person smells Hedione. They compared the results with the effects triggered by phenylethyl alcohol, a traditional floral fragrance. Hedione activated brain areas in the limbic system significantly more strongly than did phenylethyl alcohol. The limbic system is associated with emotions, memory, and motivation.