02.20.08
Posted in Biology at the University of Virginia, Infectious Disease, Jacob Canon, Parasites, The Oscar Show, UVa College of Arts & Sciences, Uncategorized, University of Virginia, biology, biomedical engineering, immune, physical health at 12:10 pm by Jacob Canon
In today’s show, adapted from an article published this month on the Oscar Web site written by Mary Jane Gore, we look at the research of Dr. William Petri, chief of the UVa Division of Infectious Diseases and International Health, and his study of a voracious parasite that is said to kill nearly 100, 000 people each year.
Pathogens & Parasites [5:40m]:
Play Now |
Play in Popup |
Download
If you have ever contemplated working as a biological researcher then you would probably have considered these questions: what happens when a cell’s life ends? And, what are the mechanisms that control decay?
Contemplating just these types questions during a recent study, a UVa-led research team, directed by Dr. William Petri, chief of the UVa Division of Infectious Diseases and International Health, made discoveries which are helping to stop one of the world’s most voracious parasites.
The team included Douglas Boettner (now completing postdoctoral work in Miami), U.Va. graduate students Alicia S. Linford and Sarah Buss and faculty colleagues Dr. Eric Houpt and Dr. Nicholas Sherman of UVa and Dr. Christopher D. Huston of the University of Vermont.
Their work revolved around the hypothesis that identifying molecules involved in the corpse ingestion would provide insight into how the amoebae cause colitis in children. These amoebae, properly known as entamoeba histolytica, cause colitis, or inflammation of the colon. They do this by attacking and killing human immune cells in mere seconds. It then it hides the evidence by eating the cells’ corpses.
In doing so, per data from Dr. Gerald Mandell of U.Va. Infectious Diseases and editor of Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases, 6th edition, this murderous marauder “on a global basis, affects approximately 50 million people each year, causing diarrhea, malnutrition and nearly 100,000 deaths.
Dr. Petri’s team identified a particular protein on the surface of the ameba called a kinase, PATMK. Their work, published in the Jan. 18 issue of PLoS Pathogens, a peer-reviewed, open-access journal from the Public Library of Science, outlined a special technique called RNA interference, which inhibits the actions of this kinase, thus preventing the amoebae from eating the dead cells.
Dr. Petri, said, “by blocking this kinase, we have for the first time prevented the ameba from colonizing and invading the gut. This means that we are a step closer to preventing this disease, which wreaks havoc among children worldwide.”
The first author of the paper, Douglas Boettner said, “infection and further invasion into the gut require the clearance of dead cells in order to prevent immune recognition of the damaged tissue. PATMK is the first individual member of a large family of proteins to be assigned a function related to the clearance of dying tissue during pathogenesis.”
Boettner added, “this protein may be a pivotal vaccination target because these preliminary studies show that alterations in PATMK function reduced progression of amoebiasis in mice, a vaccine that ultimately would prevent this ameba from clearing the damaged host may draw in helpful immune cells, and thus help to clear this infection.”
Their work has shown how infection depends upon the ameba’s consumption of dead cells. By identifying the molecule that controls this consumption, scientists are one step closer to the ultimate goal of preventing the diseases caused by this parasite.
You’ve been listening to the Oscar Show, I’m Jacob Canon. Join us next week when our topic will be the research of Adrienne Felt, a fourth-year computer science major in the School of Engineering and Applied Science, concerning privacy issues surrounding social networking platforms such as Facebook.
Permalink
01.09.08
Posted in Biology at the University of Virginia, Body Clock, Nocturnin, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, biology, circadian rhythms, evolution, hypothalamus, metabolism, physical health at 12:15 pm by Jacob Canon
In today’s show, adapted from an article published on the Oscar web site written by Fariss Samarrai, we discuss the research of Carla Green, associate professor of biology at the University of Virginia, and a study she headed which says that the gene Nocturnin, working within the network of the body’s circadian clock, appears to be particularly important in the control of metabolism.
The body’s biological clock has been shown to regulate life’s activity/rest cycles by controlling energy levels, alertness, growth, moods and the effects of aging. Further study has revealed that these internal clocks are controlled by circadian rhythms. Rhythms that were established early in the history of life on the planet and evolved associated with the astronomical cycles that effect Earth’s environment such as the rise and setting of the sun and the passing of seasons. What is now being discovered is that certain elements, already known to be part of the body’s circadian network, may have a broader influence on the life of an individual.
In a study published in the journal, Proceedings of the National Academy of Sciences, Associate Professor of Biology at the University of Virginia Carla Green and her colleagues discovered that the gene Nocturnin, which participates in the regulation of the body’s biological rhythms, may also be a major control in regulating metabolism. The study showed that mice lacking the gene were resistant to weight gain when put on a high fat diet and also were resistant to the accumulation of fat in the liver.
Professor Green, said, “It’s been known for some time that there are many links between the circadian clock and various aspects of physiology and metabolism. This study suggests that Nocturnin is part of the network that the circadian clock uses to control important aspects of metabolism.”
In the study, Green and her colleagues, Nicholas Douris, a U.Va. graduate student who designed the study, U.Va. post-doctoral fellow Shihoko Kojima and Joseph Besharse of the Medical College of Wisconsin, used regular mice and genetically altered mice in which the Nocturnin gene was not present. The Nocturnin-deficient mice were divided into two groups; one group fed a normal diet, the other a very high fat diet. A group of normal mice were also fed a high fat diet.
The researchers found that both groups of genetically altered mice maintained normal weight and activity levels, and, of particular interest, the ones fed the high fat diet exhibited only slight weight gains, even over long periods of time. However, the normal mice on the high fat diet ballooned, gaining more than twice the weight of the Nocturnin-deficient mice. And, when the mice were dissected, the researchers found that the normal mice had, as expected, large concentrations of fat in their livers, whereas the altered mice had normal levels of fat.
Green said, “We were quite amazed at what we found. We thought that over time, as we continued to feed the mutant mice the high fat diet that they would eventually gain weight at some expected rate, but it never happened. These mice continued to stay slim while the normal mice nearly doubled in weight and developed fatty livers.”
Clock genes in the body’s organs operate in conjunction with a central time keeper in the brain, the hypothalamic suprachiasmatic nucleus, but also work somewhat independently, resulting in a complex system of oscillators regulating various functions of the body. Scientists are working to better understand how the genes and proteins of the circadian clock in mammals affect not only activity cycles but also rates of metabolism, which are tied to feeding cycles. Green said it is possible that, “A better understanding of Nocturnin’s function could eventually lead to medical treatments that could counteract the problems of obesity, which has become a major issue in modern society.”
We look forward to the continued study of this important new finding in the hope that its potentially far reaching health benefits will be realized in our lifetime.
You’ve been listening to the Oscar Show… I’m Jacob Canon. Join us next week when our topic will be UVa professor and chair of biomedical engineering Thomas Skalak and his efforts to develop real scientific evidence about the effectiveness of magnetic therapy.
Permalink
12.13.07
Posted in Biology at the University of Virginia, DeForest Mellon, The Oscar Show, University of Virginia, biology, brain, crustaceans, evolution, nervous system, neurophysiology, sensory inputs, visual processing at 11:37 am by Jacob Canon
Today’s show, from an article published on the Oscar web site written by Fariss Samarrai, we examine lobsters and other crustaceans. What most people think of as food, is being utilized by UVa biology professor DeForest Mellon in his research of how the brain detects, integrates and uses co-joined yet dissimilar sensory inputs.
Inside the brain of crayfish [5:33m]:
Play Now |
Play in Popup |
Download
Imagine you are on a voyage to the bottom of the sea, or simply looking along the bottom of a clear stream observing lobsters or crayfish waving their antennae. Looking closer, you see them feeling around with their legs and flicking their antennules — the small, paired sets of miniature feelers at the top of their heads between the long antennae. While the long antennae are used for getting a physical feel of an area, such as the contours of a crevice, the smaller antennules are there to both help the creature smell and also to sense motion in the water that could indicate the presence of food, a mate or danger. The legs also have receptors that detect chemical signatures, preferably those emanating from a nice hunk of dead fish.
“They constantly flick their antennules,” says DeForest Mellon, a University of Virginia biology professor, “it is doing two things that are processed simultaneously in the brain as he flicks: smelling the water, and also sensing motion in the water, which can indicate the presence of food or other things of interest.” Mellon said, “I’m interested in understanding how these senses are combined and interpreted in the brain of these animals. My question is how does the brain detect, integrate and use these co-joined but dissimilar sensory inputs?”
“We taste food by a combination of senses, taste, aroma, texture and how good that dish looks. This complex process of brain processing is not much different with crustaceans, though their brains are much simpler, which makes them a great study model,” Mellon says. Mellon and other neurophysiology researchers commonly use crustaceans to try to gain basic understanding of the nervous systems of creatures in general. Extrapolating what they find to gain a basic understanding of the much more complex human brain.
Mellon says, “due to the large-sized nerve cells of invertebrates, we can conveniently and practically examine these systems that are largely the same among all creatures, and antennule flicking can serve as a practical model that helps us understand how two or more senses work together in the brain.”
Mellon has been investigating sensory systems for half a century, since his grad school days at Johns Hopkins University. And he’s still learning. Recently Mellon perused the research in the field — his own and that of many other scientists — of the past 45 years or so and published a review of the literature in the August 2007 issue of The Biological Bulletin.
What he’s found is that there is still much to be understood. “It’s fertile ground for ongoing research,” he said. “The size of an area of the brain devoted to a particular sense gives us a good idea of how an animal perceives the world. About 40 percent of a crustacean’s brain is devoted to the sense of smell. This shows how important detecting odors are to the animal.” “Crayfish and lobsters are generally solitary creatures, inhabiting an aquatic environment that is often dark, and they need that highly acute sense of smell.”Humans, by contrast, have less than 1 percent by volume of the brain devoted to interpreting smells, but about 30 percent of the human brain is concerned with visual processing.
Mellon said, “I have always been fascinated by the diversity of animal types and their equally diverse behaviors. Both are genetically based. And through often very subtle adoption of genetic variations in different animals, evolution has arrived at different solutions to common survival problems. This behavioral diversity and the variants in nervous system organization account for why I remain fascinated with biology.”
Permalink
12.06.07
Posted in Biology at the University of Virginia, Gaesser, Jacob Canon, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, biology, kinesiology, metabolism, physiology, stress at 1:10 pm by Jacob Canon
In today’s show we will discuss the research of UVa professor of exercise physiology Glenn Gaesser and his findings on what has come to be termed “BAD CARBS.”
With the holiday season upon us, traditional meals are a big part of the celebration. Meat, vegetables and breads are a big part of these feasts. Breads and other sources of carbohydrates have become a big concern for individuals worried about their weight and health. The latest common wisdom on carbohydrates claims that eating so-called “bad carbs” will make you fat. But University of Virginia professor Glenn Gaesser, professor of exercise physiology and director of the kinesiology program in the Curry School of Education says, “that’s just nonsense. Eating sandwiches with white bread, or an occasional doughnut, isn’t going to kill you, or necessarily even lead to obesity.”
A popular speaker, Gaesser has lectured on the subject of fitness, body weight and health at numerous national and international meetings and has appeared on dozens of radio and TV shows in North America. In an article in the October issue of the Journal of the American Dietetic Association, Gaesser analyzed peer-reviewed, scientific research on carbohydrate consumption, glycemic index and body weight. In this article he gives the first detailed review of the literature on the correlation between them. His findings run counter to the current consensus on the effects of “good” and “bad” carbs.
Gaesser, author of “It’s the Calories, Not the Carbs” and other books, found that diets high in carbohydrates are almost universally associated with slimmer bodies. More importantly, Gaesser found that consuming lots of high-glycemic foods is not associated with higher body weights. In fact, several large studies in the United States revealed that high-glycemic diets were linked to better weight control. “There is no reason to be eating fewer carbs — they’re not the enemy,” says Gaesser.
The description of carbohydrates as “good” or “bad” is based on glycemic index, a measure of the quality of the carbohydrate in terms of how much it raises blood sugar. Foods having a high GI are generally thought to be “bad” because they raise blood sugar more than “good” carbs do. Proponents of the glycemic index claim that this leads to excessive insulin secretion, which can cause weight gain and health problems. Foods such as whole-grain breads are said to offer “good” carbs, because they have a lower GI than white bread, for example. Likewise, a glass of pineapple juice has a high GI compared to apple juice. Several popular low-carb diets use glycemic index as a key feature for optimum weight control, but it is not a reliable description of carbohydrate quality, Gaesser says. Digestion is a complicated process. It’s very difficult to determine the GI of a whole meal, for instance, so it doesn’t really make sense to use GI or “glycemic load” — the glycemic index multiplied by the quantity ingested — as a guide to eating.
After looking at hundreds of articles on large-scale studies using surveys or randomized, controlled trials, Gaesser says they show that “people who consume high-carb diets tend to be slimmer, and often healthier, than people who consume low-carb diets.” Even high-glycemic foods have a place in the diet, he said, attributing that to the overall higher quality of a high-carb diet, which includes more fiber-rich and other nutritional foods.
Gaesser also looked for a clear association between carbohydrate consumption and illnesses, such as type 2 diabetes, heart disease and cancer. He found no compelling evidence that avoiding carbohydrates with a high GI helps prevent these diseases and others.Gaesser said, “People with diabetes, as well as very sedentary women who are obese, may benefit from lowering their consumption of foods with a high GI. Reducing any part of the diet — carbs, proteins or fats — will result in modest weight loss in the short term, if calorie consumption is reduced, he points out. But for long-term weight maintenance, a high-carb, low-fat diet is still the best bet.”
You’ve been listening to the Oscar Show… I’m Jacob Canon. Join us next week when our topic will be the research of UVa biology professor DeForest Mellon and his work concerning how the brain detects, integrates and uses co-joined yet dissimilar sensory inputs.
Permalink
11.15.07
Posted in Buddhist, Elevation, Jacob Canon, Psychology, Relationships, Social Psychology, The Oscar Show, University of Virginia, anxiety, biology, brain, emotions, ethics, happiness, philosophy, physical health, positive psychology, stress at 10:24 am by Jacob Canon
When social psychologist University of Virginia in 1995, he prepared by reading Thomas Jefferson’s writings and making the requisite pilgrimage to Monticello. Little did he realize the impact this Jeffersonian indoctrination would have on his own research.
Haidt’s area of specialization is moral emotions, but before coming to U.Va., he focused his studies on cross-cultural experiences of disgust. He read ancient Buddhist texts and spent time in India, exploring how the beneficial biological aspects of disgust became codified as religious imperatives and keys to social order.
Then he came across Thomas Jefferson’s letter to Robert Skipwith, in which Jefferson describes how “witnessing acts of beauty and moral goodness — whether in literature or reality — swells the chest and inspires a desire to lead a better life.” Suddenly Haidt began thinking about the antithesis of disgust, the psychological effect of uplifting experiences, an emotion he termed “elevation.” Haidt said,“That letter fundamentally changed the course of my research.”
In a moment of zeitgeist, Haidt’s inquiry into elevation coincided with the burgeoning of the academic field, positive psychology, which studies how people find meaning and happiness in life. His research into what prompts elevation and the resulting physical and motivational effects won him psychology’s largest monetary award, the John Templeton Prize for Positive Psychology, in 2001.
While researching elevation, Haidt continued teaching a large undergraduate survey course introducing the study of psychology. In the classroom, he has found it useful to cite quotations and examples from ancient philosophy and world religion to make his points more memorable. Haidt’s colleague, psychology professor Gerald Clore stated, “This penchant for asking what it all means makes him very appealing as an undergraduate lecturer in Introductory Psychology.”
Having received several university and state awards for teaching, Haidt decided to apply his ancient wisdom approach to a study of happiness. Looking at the relationship between what religious and philosophical traditions say about fulfillment and what scientists have discovered about the biological processes involved in the brain’s response to stimuli, Haidt gleaned 10 psychological truths from ancient religious and philosophical texts, which he examines in the 10 chapters of his 2006 book, The Happiness Hypothesis: Finding Modern Truth in Ancient Wisdom.
Throughout the work, Haidt analogizes the conscious mind to a rider straddling the elephant of the unconscious mind, trying to guide the giant beast where the rider wants it to go. He cited numerous psychological experiments that demonstrate how at odds the conscious and unconscious minds often are, despite the conscious mind’s skill at rationalizing choices and behavior. His book suggests that by understanding ancient wisdom’s insights into our divided nature, we have a chance of establishing a more harmonious relationship between the conscious and unconscious, gently training our elephants to do as we wish.
Haidt, who has also established an accompanying website, Happinesshypothesis.com , said, “every good idea I’ve ever had in my life is in this book, the book is really a gateway to everything I want to work on for the rest of my life.” Although Haidt spent 2005-2006 at Princeton University as the Laurence S. Rockefeller Visiting Professor of Ethics at the Center for Human Values, his heart remains in Charlottesville. Haidt said,“it really was because of U.Va., because of Jefferson, that I came to study this completely neglected area of emotion.”
Haidt is currently studying the foundations of moral judgment in liberals and conservatives in order to understand how political appeals might be better crafted. In addition, he’s researching how the application of elevation can be used to increase trust in relationships, especially among married couples.
To learn more about his work and this area of study, visit www.happinesshypothesis.com.
Permalink