Friday, December 31, 2010


Kudzu (Pueraria lobata or P. montana) is a vine that is part of the pea family, Fabaceae, introduced to the United States from Asia in the late 1800s. Farmers in the southeastern states planted the vine because of its fast growth with a plan to reduce soil erosion and possibly use it as animal feed. The vine also belongs to the legume family, which includes plants that capture nitrogen at the plant root and make it available for the plant’s use; this process is called nitrogen fixation. Kudzu, however, does not control erosion. Instead it bursts into growth so prolific that it engulfs every stationary thing in its path. Those early farmers probably soon discovered that without constant cutting, the vine overgrew yards, gardens, trees, orchards, stream banks, hillsides, and even abandoned houses and farm equipment. In 2005 Georgia farmer Jason Millsaps told National Geographic, “I’ve measured a foot a day [of kudzu growth]. It’s a never-ending battle to keep it back.” Kudzu remains a very big problem in U.S. agriculture, and universities have set up project teams to work solely on the task of solving the kudzu problem.

Source of Information : Green Technology Conservation Protecting Our Plant Resources
Kudzu is one example of an aggressive invasive plant, nonnative to the United States. The vine has spread from its origins to the rest of the southeastern states, from Florida north to Maryland and west to Texas. Some farmers have nicknamed it “the vine that ate the South.” At the current rate of global warming, scientists predict kudzu will spread to Michigan in about 30 years. The University of Arkansas agricultural research station offers on its Web site the following: “The joke goes that you should fertilize kudzu in a dry year with motor oil because lubricating the undersides of the leaves reduces the chance of sparks as it races across the ground.” This fast growth explains why many invasive plants threaten the surroundings they enter; nature simply cannot adapt fast enough to repel them.

Aggressive plants may be the most harmful of all invasive species because they disrupt the foundation of ecosystems. Aggressive invaders kill or dislodge native photosynthetic plants that support a community of herbivores, carnivores, and predators in addition to microbes and invertebrates Kudzu also blocks sunlight from reaching soil organisms, overwhelms tree trunks and leaves, and can literally choke any woodland it overruns.

Kudzu removal is difficult for the following five reasons: (1) it creates deep and extensive root systems; (2) it grows back within days of cutting; (3) kudzu has no natural enemies outside Asia; (4) its seeds disperse easily, carried by wind, water, and animals; and (5) the herbicides active against kudzu also kill many native plants. Entomologist David Orr of North Carolina State University told the New York Times in 1998, “It takes a 55-gallon drum of herbicide to kill just one acre, and even then you don’t really kill it.” Protection against kudzu invasion may require a combination of new technologies and a certain amount of cleverness.

New techniques meant to save pristine forests from kudzu attack may soon employ caterpillars called soybean loopers, which have been engineered in laboratories to devour kudzu leaves as they do soybean plants. Though this research has been conducted since the mid-1990s, research has yet to find the right approach for looper-destruction of the thousands of square miles of kudzu infestation. Another approach under study involves a fungus named Colletotrichum gloeosporioides, which causes a deadly infection in kudzu after the fungus has been grown and strengthened in a laboratory. These and other biological means of fighting kudzu must come onto the scene quickly in order to help agriculture threatened by invasion.

Meanwhile, research into kudzu’s valuable properties has taken shape. Perhaps kudzu can be made into a food source or serve as a sustainable answer to deforestation. Botanists have explored kudzu’s use in pulp and papermaking, for example. University of Toronto botanist Rowan Gage told CBC News in Canada in 2007, “If you can develop it as a commodity, kudzu can pay for its own control.” Kudzu’s commercial use may be a long way off, but the fact that kudzu has caught the attention of people in Canada attests to the vine’s ability to grow and invade. Solutions from any sector of research will be helpful.

Tuesday, December 28, 2010

Conserving Nature’s Pharmacy

The timber industry has a logical need to cut down forests in order to get the raw material it requires for making wood products. But leaving forests intact gives a different industry, the pharmaceutical industry, an opportunity to explore for new products. At least 120 different chemicals used in medicines today derive from plants or trees, especially from the jungles and rain forests of the Tropics, the very places that contain the fastest deforestation rates. Therefore, a science called ethnobotany has developed to learn more about plant-derived drugs before the plants disappear and to find ways of gathering drug producing plants in a sustainable manner.

Ethnobotany is the study of relationships between native cultures and the plant life indigenous (native) to the area where the plants live. Tropical societies have long used plant- or tree-derived medicines as part of their culture, and now some pharmaceutical companies have followed that lead and established screening programs to find as many medicinal chemicals from plants as possible, as quickly as possible. Ethnobotanists take a multifaceted approach that serves the needs of large corporations and small local communities. Ethnobotany stresses two objectives that must be met together, not separately: gaining knowledge on the traditional medicines of indigenous tribes of tropical forests and (2) conserving the forests. These two objectives set ethnobotany apart from commercial bioprospecting, in which company scientists enter the forest for the sole purpose of finding and removing useful biological products.

Ethnobotanists visit local tribes to learn their customs and methods of healing, and usually the community’s shaman, or healer, shows the study team the types of trees and plants that have produced various cures since ancient times. Some medicines come only from particular leaves, or bark, or even from insects that live only on a specific plant. Mark J. Plotkin was an early advocate of ethnobotany for the purpose of learning the medicinal practices of rain forest communities. He described for the New York Times in 1999 one of his first experiences in the forest, which turned out to be a revelation for him. On a visit to South America, Plotkin introduced himself to a shaman of the Sikiyana-Chikena tribe. Times reporter John Christensen described the meeting: “He [Plotkin] then followed the shaman into the forest and watched him pick a trailside herb, peel long strips of bark from a towering tree and drain sap from a twisted vine. Back at the village, he boiled all the ingredients together in a clay pot over a wood fire. That night, the shaman gave the thick reddish-brown liquid to a young Indian woman with a nearly fatal case of diabetes. The next morning her blood sugar level was almost normal. Within a few days she was well enough to work in her garden again.” A small number of scientists took note of the opportunities hidden in the jungle; some wished to work with local communities in a cooperative way, but undoubtedly others sought only to exploit the resources.

Plotkin has criticized bioprospecting and has urged his scientific teams to work with the local people, rather than take knowledge and chemicals to the United States without giving something back to the local community. In an interview with, Plotkin explained, “I think the whole concept of intellectual property rights boils down to a question of good manners. If you’re going to compensate local or indigenous people, you want to do so in a culturally sensitive way. But you cannot say, ‘okay—we’ll be back in twelve years and, if we have a cure for AIDS, you’ll
be in the money.’ These people have real needs now.” Plotkin now heads the Amazon Conservation Team, which sets up medical clinics and implements apprentice programs with local tribes so they may learn forest conservation principles and computer skills.

In the long term, ethnobotanists help support the biological and cultural diversity of the places they visit. Similar conservation projects now take place all over the world, including projects in the United States with Native American tribes, who already have followed sustainable practices for generations. In addition to sharing information on health and medicine, ethnobotanists try to ensure that the end result of their studies is to support local communities and preserve their forested environment.

Source of Information : Green Technology Conservation Protecting Our Plant Resources

Saturday, December 25, 2010

Marijuana Hurts Some, Helps Others

Cannabis can kill or rescue neurons—children are at risk, whereas adults may benefit

Clinton didn’t inhale, Obama did— and maybe Reagan should have. New research suggests that THC, the chemical that gives marijuana its mind-bending properties, kills developing neurons, yet oddly, the same chemical saves neurons in adults with Alzheimer’s disease.

“Marijuana is not the ‘soft drug’ people like to think it is,” says neuropharmacologist
Veronica Campbell of Trinity College in Dublin, whose latest study uncovered the harmful effects of THC on young neurons. When Campbell and her co-workers treated brain cells from newborn or adolescent rats with THC, the neurons died, but THC did not have such deadly effects on neurons taken from adult rats. In fact, work from other labs shows that THC benefits adult neurons. “We don’t know why,” Campbell says. Several possibilities are being investigated for this “Jekyll and Hyde” effect.

Marijuana, like tobacco and opium, has powerful effects on the brain because certain compounds in the plant happen to have a chemical resemblance to naturally occurring substances in the body. Called endocannabinoids, these natural chemicals regulate important brain functions by controlling synapses in neural circuits that process thought and perception. According to several recent studies, these chemicals have many other functions in the brain and immune system, too—including regulating development and aiding survival of young neurons, as well as controlling the wiring of neurons into circuits for learning and memory. Smoking marijuana during the period of life when the brain is still developing obscures these critical chemical signals, Campbell suspects.

The slaughter of young neurons by THC could explain the developmental cognitive impairment seen in children born to women who smoked marijuana during pregnancy. In addition, some research on adolescent marijuana abusers shows brain damage in neural circuits that are still developing at that age.

In older brains, however, THC seems to have a protective effect. Campbell’s findings indicate that the biochemistry of neurons changes as the cells mature. The role of endocannabinoids shifts to regulate different functions—most important, assisting in the survival of aged neurons. In patients with Alzheimer’s disease, THC protects neurons from death in several ways. THC boosts depleted levels of the neurotransmitter acetylcholine, which, when diminished, contributes to the weakened mental function in Alzheimer’s patients. THC also suppresses the toxic effects of the socalled a-beta protein that may kill neurons in Alzheimer’s disease. It stimulates secretion of neuron growth by promoting substances such as brainderived neurotrophic factor, and it dampens release of the excitatory neurotransmitter glutamate, which kills neurons by overstimulation. THC and other cannabinoids also have powerful anti-inflammatory and antioxidant actions that protect neurons from immune system attack.

Despite these benefits, THC and other compounds in marijuana also have many undesirable side effects on the brain. The trick for scientists will be to isolate the active ingredients in marijuana that are beneficial and develop drugs that can be applied in the proper dose for the specific age of the patient. Campbell finds that the beneficial effects of THC are seen in much lower concentrations of the chemical than are found in the plants people use to get high. “It’s a matter of trying to balance that low concentration within a nice safety margin,” she explains. Synthetic THC-like drugs are already available, as is a naturally derived drug called Sativex that contains THC and other cannabinoids, approved in Canada for treating pain from multiple sclerosis and cancer.

In contrast to these well-controlled drugs, the weed itself is a complex witches’ brew of many brain-altering chemicals. The cannabis plant contains about 60 different cannabinoids, so the challenge lies in trying to tease out which are the important ones for protecting neurons, Campbell explains, echoing the views of other marijuana researchers. “Depending on how the plant is cultivated, the relative proportion of the different types of cannabinoids changes,” she says. “The ‘joints’ that are available now are much stronger in terms of their THC content than those that would have been around when people were thinking of cannabis as being quite a soft drug.”

Source of Information : Scientific American Mind September-October 2009

Thursday, December 23, 2010

Inflammation Brings on the Blues

Our immune system may mean well, but it might also cause depression

As if being stuck sick in bed wasn’t bad enough, several studies conducted during the past few years have found that the immune response to illness can cause depression. Recently scientists have pinpointed an enzyme that could be the culprit, as it is linked to both chronic inflammation— such as that found in patients with coronary heart disease, type 2 diabetes and rheumatoid arthritis—and depressive symptoms in mice.

In the new study, immunophysiologist Keith Kelley and his colleagues at the University of Illinois exposed mice to a tuberculosis vaccine that produces a low-grade, chronic inflammation. After inoculation, production in the mice brains of an enzyme called IDO, which breaks down tryptophan, spiked. The animals exhibited normal symptoms of illness such as moving around and eating less. Yet even after recovering from the physical illness induced by the vaccine, they showed signs of depression—for example, struggling less than control mice to escape from a bucket of water. Surprisingly, their listlessness was solved relatively simply. “If you block IDO, genetically or pharmaceutically, depression goes away” without interfering with the immune response, Kelley explains.

The research makes a solid case that the immune system communicates directly with the nervous system and affects important health-related behaviors such as depression. The findings could bring relief to patients afflicted with obesity, which leads to chronic inflammation, as well as to cancer patients treated with radiation and chemotherapy drugs that produce both inflammation and depression. “IDO is a new target for drug companies to aim for, to treat patients with both clinical depression and systemic inflammation,” Kelley says.

Source of Information :  Scientific American Mind September-October 2009

Tuesday, December 21, 2010

Underwater Suffering?

A study suggests fish consciously experience discomfort

Many a seafood fan has parroted the popular idea that fish and crustaceans do not feel pain. New research, however, suggests that they may, revealing that their nervous system may be more complex than we thought—and our own awareness of pain may be much more evolutionarily ancient than suspected.

Joseph Garner of Purdue University and his colleagues in Norway report that the way goldfish respond to pain shows that these animals do experience pain consciously, rather than simply reacting with a reflex— such as when a person recoils after stepping on a tack (jerking away before he or she is aware of the sensation). In the study, the biologists found that goldfish injected with saline solution and exposed to a painful level of heat in a test tank “hovered” in one spot when placed back in their home tank. Garner labels that “fearful, avoidance behavior.” Such behavior, he says, is cognitive—not reflexive. Other fish, after receiving a morphine injection that blocked the impact of pain, showed no such fearful behavior.

Although Garner’s findings fit with previous work that tentatively suggests that fish feel pain, some experts remain unconvinced that the reaction was not an instinctive escape behavior. Still, the new study raises ethical concerns. “If we’re going to use animals in experiments, and we’re going to use animals as food, then it is really important to understand the consequences of our actions for those animals,” Garner says.

Source of Information :  Scientific American Mind September-October 2009

Saturday, December 18, 2010

Indoor Air Quality

If you’re like most people, when you worry about pollution, you think about the particles in the air outside. After all, that’s where cars drive, dust blows, and factories do their dirty work. But air-quality experts know the grimy truth—when it comes to air pollution, your lungs may have more to fear indoors than they do outside.

If this seems contradictory, you need to take a closer look at the environment where you spend most of your time. Items that fill many modern homes, such as carpeting, furniture, paint, and cleaning supplies, can release volatile organic compounds (VOCs). In addition, biological sources such as dander from your pets, skin flakes from your body, and spores of mold contribute to indoor air pollution. And because modern homes are surprisingly airtight, particles can build up to concentrations you’d never face outdoors. Add to this the fact that the average person spends 90 percent of the day inside, and you can see why your lungs have more to worry about from a relaxing day at home than a walk around the block.

So what can you do to improve indoor air quality and reduce your exposure to PM2.5 particles? Here are some proven techniques:

• Ventilate. Opening a window is one of the easiest ways to clear out indoor air pollutants. Even without a strong breeze, built-up pollutants will naturally spread out and drift out of an open window. Of course, this technique isn’t as useful on a hot and smoggy day, or if you live near a pollution source (say, a few feet from a heavily trafficked road). In cases like these, you might get more mileage out of an air exchanger, which brings in outside air, filters it, and uses it to heat or cool your house.

• Use exhaust fans. Stovetop cooking creates plenty of potential lung irritants, and our hot, steamy showers generate the humidity that allows mold to thrive. To cut down on these sources of indoor air pollution, make sure you have an exhaust fan in every kitchen and bathroom. Use the kitchen exhaust fan while cooking, and use the bathroom exhaust fan while cleaning and after bathing.

• Air out. Air-quality experts recommend that you air out problem items before you bring them into your house. This includes dry-cleaned clothes and new carpet, both of which release hefty quantities of VOCs. (New carpet will probably continue releasing VOCs 2 or 3 years after installation, but you can cut down on the intense initial exposure by giving it a couple of days to air out—or better yet, by going with hard floor coverings, like wood.)

One common indoor air pollutant is the residue left from cigarette smoke. Health researchers have coined the term third-hand smoke to describe the toxic particles that remain long after the visible smoke has drifted away, clinging to furniture, carpeting, upholstery, and clothing. New, but somewhat controversial, research suggests that exposure to this residue can be damaging. It’s a particular concern for young children, who are likely to crawl along particle-laden carpets.

A regular dose of fresh air keeps your indoor environment healthy. Ventilation is particularly important when you do something that releases large amounts of indoor pollutants, such as painting (even with low-VOC paints) and using strong cleaning products (like those you use to clean the bathroom, floor, oven, and so on).

Source of Information : Oreilly - Your Body Missing Manual