Tag Archives: dna

Genomic analysis lends insight to prostate cancer

"This is the first study to examine DNA alterations using next generation sequencing in adjacent Gleason patterns in the same tumor allowing us to correlate genomics with changes in pathology," says John Cheville, M.D., Mayo Clinic pathologist and one of the authors on the paper. The standard method of evaluating prostate cancer biopsy samples is a numerical scoring system called Gleason grading. A pathologist examines the tumor sample under the microscope, giving it a Gleason score based on the pattern of its cells…

Dogs bring swarm of bacteria into your home

Your loyal pooch may be bringing a whole world of bacteria into your home but don't panic. Research suggests that exposure to a wide variety of microbes may be good for us. A new study reveals that homes with dogs have greater bacterial diversity than canine-free dwellings. Dog-related diversity is particularly high on television screens and pillowcases, the researchers found. “When you bring a dog into your house, you are not just bringing a dog, you are also introducing a suite of dog-associated [microbe] taxa directly into your home environment, some of which may have direct or indirect effects on human health,” the researchers wrote today (May 22) in the journal PLOS ONE. [5 Wacky Things That Are Good For You] Microbes around us The microbes in our environment are the subject of increased interest by scientists, thanks to studies revealing how intertwined human lives are with those of the single-celled. Skin microbes, for example, may be key for warding off disease. And the load of microbes living in the human gut may influence everything from immunity to obesity. North Carolina State University biologist Rob Dunn and his colleagues wanted to step back from the body to better understand the microbes in our environment at large. They gave 40 families a home-sampling kit and asked them to swab down nine locations in their houses: a kitchen cutting board, a kitchen counter, a refrigerator shelf, a toilet seat, a pillowcase, a television screen, the main door's exterior handle and the upper trim on both an interior door and on an exterior door. The researchers then examined the microbial DNA from the swabs to detect different families of microscopic tenants living on these surfaces. All told, the 40 homes harbored 7,726 different types of bacteria. The most common were Proteobacteria, Firmicutes and Actinobacteria, all families containing a wide range of species. Types of bacteria tended to differ by location: Kitchen environments (cutting boards, counters and shelves) had similar colonies from home to home, as did frequently touched surfaces (toilet seats, pillowcases, door handles) and rarely cleaned surfaces (door trims and television screens). “This makes sense,” Dunn said in a statement. “Humans have been living in houses for thousands of years, which is sufficient time for organisms to adapt to living in particular parts of houses. We know, for example, that there is a species that only lives in hot-water heaters. We deposit these bacterial hitchhikers in different ways in different places, and they thrive or fail depending on their adaptations.” Bacteria related to human skin were found most frequently on pillowcases and toilet seats as were bacteria commonly found in human feces. Bacteria from leaves and produce were found most often on door trims and also on kitchen surfaces. Bacteria from the soil were found across the home, but were most common on the exterior door trim, the researchers found. Doggie diversity Dunn and his colleagues next looked for variables that would alter bacterial communities from home to home, such as the presence of cats, children, carpet and other factors. The only one they found that made any difference was whether or not the family had a pet dog. Pillowcases and TV screens of dog-owning families had 42 percent and 52 percent more microbial groups, respectively, than pillowcases and TV screens of non-dog-owning families. This extra diversity, unsurprisingly, was made up largely of bacteria known to live on dog fur. (Other factors, such as the level of humidity in a home, could also influence microbe diversity, the researchers wrote, but they were unable to measure those factors in this study.) Dog owners shouldn't ship Fido off to the countryside for fear of nasty bacteria, though. In fact, the family pet may be a boon to health. Previous studies have found that pregnant women who live in homes with dogs are less likely to have children with allergies. Scientists speculate that the reason might be an exposure to greater numbers of microbes that keeps the immune system from turning on the body. “Our study provides evidence to robustly support this assumption,” Dunn and his colleagues wrote. The researchers are planning to process samples from a total of 1,300 homes across the United States to look for geographic differences in microbial roommates. Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.source : http://www.foxnews.com/health/2013/05/23/dogs-bring-swarm-bacteria-into-your-home/

Feet contain most fungi on body, new research shows

A new map of the fungal species lurking on human skin reveals the most diverse communities can be found on — you guessed it — the bottom of the feet. Genetic sequencing found the fungal genus Malassezia dominated on most of the core body regions and arms. The heel, toenail and toe web (skin between the toes), by contrast, supported highly varied fungal communities. Imbalances in these populations may lead to athlete's foot and other fungal diseases, the researchers say. The skin serves as a barrier to pathogenic microorganisms, but is also home to a rich array of harmless microbes. Until now, most efforts to study the skin's microorganisms have focused on bacterial species, but fungi (which are a distinct biological group) form a significant part of these skin communities. Feet love fungi In the study, scientists took skin scrapings from 10 healthy adults at 14 different sites on the body. They sequenced the DNA from the swabs. In addition, the researchers isolated more than 130 fungal strains from the genera Malassezia, Penicillium and Aspergillus, and grew them in the lab.   The genus Malassezia, which may cause dandruff, was the most abundant type of fungus at all 11 core-body and arm sites, results showed. These areas included the inner elbow, palm, space between the eyebrows, back of the head, nostril and forearm, among other spots. Core-body sites, such as the chest and abdomen, had the fewest types of fungi, ranging from two to 10 genera. The three foot sites — heel, toenail and toe web — contained much greater fungal diversity, with populations of Malassezia¸ Aspergillus, Cryptococcus, Rhodotorula and Epicoccum, among others. Overall, the heel had the most diverse fungal makeup, with about 80 fungal genera. One study participant had an especially diverse array of fungi. This person had taken a course of oral antifungal medication for a toenail infection seven months prior to the study. The unusual fungal diversity suggests that either an imbalance in the fungal community was causing the stubborn toenail infections, or that changes in the microbe composition due to the medication continued even seven months after stopping treatment, the researchers say. The results demonstrate that human skin is capable of harboring a highly varied fungal population. When fungi go awry The researchers also sequenced bacteria on the skin. The results confirmed previous findings for skin bacterial makeup in healthy people. In contrast to fungal populations, the most diverse bacterial populations were found on the arms. The person with abnormal fungal diversity appeared to have a normal distribution of bacteria. The study of the skin's native fungi has important implications for infection and disease. About 20 percent of the study participants showed signs of possible foot fungal infections, and previous studies have shown up to 60 percent of healthy people may harbor such infections. Fungal infections affect 29 million North Americans. Several factors influence the prevalence of fungal infections, including population and climate. Antifungal medications can have dangerous side effects, and new treatments that target fungal imbalances are needed, the researchers say. The findings were reported online May 22 in the journal Nature.  source : http://www.foxnews.com/health/2013/05/22/feet-contain-most-fungus/

Scientists uncover how grapefruits provide a secret weapon in medical drug delivery

Grapefruits have long been known for their health benefits, and the subtropical fruit may revolutionize how medical therapies like anti-cancer drugs are delivered to specific tumor cells. University of Louisville researchers have uncovered how to create nanoparticles using natural lipids derived from grapefruit, and have discovered how to use them as drug delivery vehicles. UofL scientists Huang-Ge Zhang, D.V.M., Ph.D., Qilong Wang, Ph.D., and their team today (May 21, 2013), published their findings in Nature Communications. …

Genetic diversity within tumors predicts outcome in head and neck cancer

"Our findings will eventually allow better matching of treatments to individual patients, based on this characteristic of their tumors," says Edmund Mroz, PhD, of the MGH Center for Cancer Research, lead author of the Cancer report. "This method of measuring heterogeneity can be applied to most types of cancer, so our work should help researchers determine whether a similar relationship between heterogeneity and outcome occurs in other tumors." For decades investigators have hypothesized that tumors with a high degree of genetic heterogeneity — the result of different subgroups of cells undergoing different mutations at different DNA sites — would be more difficult to treat because particular subgroups might be more likely to survive a particular drug or radiation or to have spread before diagnosis. While recent studies have identified specific genes and proteins that can confer treatment resistance in tumors, there previously has been no way of conveniently measuring tumor heterogeneity. …

Link between tumor suppressors and starvation survival suggested

CU-Boulder Professor Min Han said the research team was interested in how a common tumor suppressor gene known as Retinoblastoma 1, or Rb, behaved under conditions of starvation. The question is important, said Han, because it may help researchers understand why many cancer cells are more susceptible to starvation or fasting than ordinary cells. Han and his team studied a popular lab organism called C. elegans, a translucent nematode smaller than an eyelash…