12.27.07
Posted in American bellflower, Biology at the University of Virginia, Evolutionary biologist, Galloway, Jacob Canon, Mountain Lake Biological Station, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, adaptation, environmental conditions, environmental science, environmental scientist, genetic, maternal effects at 12:36 pm by Jacob Canon
Today’s show, taken from an article published on the Oscar web site written by Melissa Maki, is about evolutionary biologist Laura Galloway. Galloway’s work indicates that maternal plants give cues to their offspring helping them adapt to their environment.
Seeds of Change; Mother Knows Best [4:36m]:
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Have you ever heard the phrase, “I didn’t fall far from the tree.” Well, this can be especially important in the plant world. When habitat changes, animals migrate, but how do immobile organisms like plants cope when faced with alterations to their environment? This is an increasingly important question in light of new environmental conditions brought on by global climate change.
Evolutionary biologist Laura Galloway, an associate professor of Biology at the University of Virginia, recently completed a study of the American bellflower. This University of Virginia study, published in the Nov. 16 issue of The Journal Science, demonstrated that plants grown in the same setting as their maternal plant performed almost three and a half times better than those raised in a different environment. Indicating that maternal plants give cues to their offspring that help them adapt to their environmental condition.
What led to this line of inquiry was, a number of years ago Galloway observed that plants that had experienced drought had smaller seeds than those that had not. It was this highly visible physiological change within only one generation that intrigued her. This focused Galloway’s research on the transmission of environmental information between maternal plants and their offspring.
The American bellflower is a native wildflower that commonly grows in both shaded areas and areas that receive full sunlight for at least part of the day. Conducted in a natural habitat at the University of Virginia’s Mountain Lake Biological Station in Southwest Virginia, Galloway planted some seeds in light conditions similar to their maternal plants and some in different light. She found that plants growing in the same setting as their maternal plant outperformed those planted in a different environment.
Since plant adaptation is typically studied on a permanent, genetic level rather than in direct response to environmental conditions, Galloway’s insights are unique. Seeds typically fall close to their maternal plant, they grow in a similar environment. But, when seeds are dispersed to different environments, Galloway found that the plants may suffer for one generation, but as long as the seeds of those plants grow locally, their offspring will recover.
Galloway said, “We found a temporary mechanism of adaptation to local environmental conditions. Historically, maternal effects have been viewed as a complicating factor — an inconvenience. But we have found that they can dramatically influence the performance of an individual.
You’ve been listening to the Oscar Show… I’m Jacob Canon. I would like to thank all of you who have joined me this year exploring many of the topics of research at the University of Virginia.
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12.20.07
Posted in Eastern Shore, GPS, Hog Island Bay, Jacob Canon, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, VIMS, Virginia Institute of Marine Science, coastal bays, crustaceans, environmental science, environmental scientist, marine life, restoration at 11:55 am by Jacob Canon
Today, from an article found on the Oscar web site written by Faris Samarrai, we discuss the efforts being made by environmental scientist Karen McGlathery to reestablish the natural environment needed to insure those crustaceans and other marine life can thrive and return to their previous population levels on Virginia’s Eastern Shore.
Planting the Seeds of Change [5:15m]:
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As environmental scientist Karen McGlathery slips from the side of the boat into the shallow, murky waters of Hog Island Bay, one of three major lagoons on the oceanside of Virginia’s Eastern Shore, the chill of the morning water hits her, she exclaims “Oh, that’s cold.”
McGlathery is the University of Virginia’s lead investigator on a project to restore sea grasses to the region. Last fall she worked with a team of scientists from VIMS, the Virginia Institute of Marine Science, to seed a 500-acre area of Hog Island Bay with eelgrass, a submerged sea grass that is common in temperate waters worldwide. It was hoped it would establish a meadow that may eventually spread outward, potentially propagating new areas.
McGlathery and her team of graduate students, a few undergrads and even a couple of local high school students, are now back to see if the grass is growing. The team finds the site using GPS — the Global Positioning System — to pinpoint their plots, which are not visible from the surface of the turbid water. They wade and snorkel along the beds, taking measurements of the length of the grass and the extent to which it has spread. They also take core samples from the muddy bottom, and water samples for later analysis. McGlathery said, “what we learn from these studies will help us determine the baseline conditions for future restoration efforts.”
Sea grass once flourished in the seaside bays of the Eastern Shore. But in the late 1920s and early 1930s a pathogen began killing the grasses. A hurricane in 1933 essentially finished them off. In the years since, the bay bottoms have been mostly muddy and barren. A once thriving scalloping and fishing industry collapsed. “I’ve read accounts by old watermen of how the water here was once crystal clear and that the sea grass meadows were so extensive and visible from the surface that it looked like a lawn of long grass,” McGlathery said.
Not anymore. The water is murky green most days and even muddy on windy days. Without extensive sea grass beds to stabilize the bottom, the sediment is continually stirred up, blocking out the sunlight needed by eelgrass to photosynthesize and flourish. But when grasses grow well, they stabilize the bottom, clear up the water and serve as habitat for an assortment of creatures: scallops, crabs, shrimp, mollusks, and the fish that feed on these animals.
McGlathery is encouraged by what she is finding. Most of the half and one acre plots in the 500-acre area are doing well. Apparently, about 10 percent of the 1.5 million seeds that were scattered last fall took root and the plants are growing. Many are 12 to 18 inches long. McGlathery is not surprised. Prior to the seeding, she and her team surveyed the area, tested the sediment and the water quality, and determined that the area might be receptive to a crop of eelgrass.
VIMS has conducted similar work during the past 10 years in South Bay, a lagoon to the south of Hog Island Bay, that extends between the barrier islands of the Virginia. “In areas of South Bay there are now lush sea grass beds… as far as you can swim, continuous meadows,” McGlathery said. “It shows that we can not only get these grasses to grow, but we can also get them to thrive.” And recently, scientists discovered a few sparse natural areas of eelgrass in Hog Island Bay, likely seeded by tide and current from the manmade beds in South Bay.
It is hoped that these restoration efforts will allow the coastal bays to regain their health and vitality, leading to the return of the indigenous marine populations in the waters of the Eastern Shore.
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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]:
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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.”
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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.
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