Roxanne Khamsi When snakes evolved venom, they co-opted proteins from all over their bodies, says an analysis of 24 different toxins. Surprisingly, very tiny tweaks were enough to transform harmless proteins into deadly poison, and this may help drug designers to create proteins with precise biological effects. Venomous snakes developed glands for the storage and dispersal of their saliva about 60-70 million years ago. Since then, various species have built up an arsenal of toxins to attack their victims. Different venoms attack different types of cell in the body, for example muscle cells or blood cells. This dramatic specificity has led scientists to speculate that the venoms originate from proteins produced in different organs throughout the body, which already interact with these cell types. But champions of this theory lacked hard evidence from more than a few toxins. Despite the incredible changes in bioactivity that occur, the proteins' basic shapes don't change notably. ©2005 Nature Publishing Group

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 6950 - Posted: 06.24.2010

David Perlman, Chronicle Science Editor There stood Jack Dumbacher, innocently trying to trap a gorgeous bird of paradise in the mist net he'd set up for his research in a New Guinea forest, when the net entangled a flying stranger, all vivid orange and black. The unwanted bird clawed Dumbacher's fingers, nipped them with its beak, and when the startled scientist put a bleeding finger to his mouth, he suddenly felt a burning, tingling sensation on his tongue and lips -- which soon became briefly numb. The bird was a hooded pitohui (pronounced PIT-a-hooey), and the encounter in Papua New Guinea 15 years ago led the ornithologist to abandon his research into birds of paradise and to follow a mysterious, deadly poison that links the birds in the highland Papuan villages to frogs in the lowland South American jungles of Colombia -- and to beetles in both far-off habitats. Dumbacher and his colleagues have now discovered that a family of beetles in New Guinea and their distant relatives more than 9,500 miles away, on the other side of the Pacific, are apparently responsible for the toxins in Dumbacher's pitohui birds -- the first poisonous birds discovered anywhere - - and Phyllobates terribilis, the poison-dart frogs of Colombia. The frogs got their name because the Choco Indians use the same poison to tip their arrows and blowpipe darts when they hunt for monkeys and other game animals. ©2005 San Francisco Chronicle

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 6865 - Posted: 06.24.2010

Hyperactive fish, stupid frogs, fearless mice and seagulls that fall over. It sounds like a weird animal circus, but this is no freak show. Animals around the world are increasingly behaving in bizarre ways, and the cause is environmental pollution. The chemicals to blame are known as endocrine disruptors, and range from heavy metals such as lead to polychlorinated biphenyls (PCBs) and additives such as bisphenol A. For decades, biologists have known that these chemicals can alter the behaviour of wild animals. And in recent years it has become clear that pollutants can cause gender-bending effects by altering animals' physiology, particularly their sexual organs. But now two major reviews have revealed that the chemicals are having a much greater impact on animal behaviour than anyone suspected. Low concentrations of these pollutants are changing both the social and mating behaviours of a raft of species. This potentially poses a far greater threat to survival than, for example, falling sperm counts caused by higher chemical concentrations. © Copyright Reed Business Information Ltd.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 6065 - Posted: 06.24.2010

NYBORG, DENMARK--The next time you step on a cockroach, you may be committing an act of mercy. At least its end will come quicker than it would have if the insect fell prey to the parasitic wasp Ampulex compressa, which delivers a paralyzing sting to the brain so that its hungry brood can devour the living roach from the inside out. Now researchers have found receptors on the wasp's stinger that may guide the neurotoxic strike. The sting of A. compressa paralyzes its prey, the cockroach Periplaneta Americana, for 4 or 5 weeks--enough time for the wasp's eggs to hatch, feed, and pupate inside their helpless host. For this strategy to work, the wasp must deliver its venom--a cocktail of neurotoxins--directly to the roach's brain. To investigate what guides the sting, Ram Gal and Frederic Libersat of Ben-Gurion University in Beer-Sheva, Israel, first introduced the wasp to roaches whose brains had been removed. Normally, it takes about a minute for the wasp to find its target, sting, and fly off. But in the brainless roaches, the wasps searched the empty head cavity for an average of 10 minutes. A radioactive tracer injected into the wasps revealed that when they finally did sting, they used about 1/6 the usual amount of venom. The wasps knew something was amiss, says Gal, who presented the findings here on 10 August at a meeting of the International Society for Neuroethology. Copyright © 2004 by the American Association for the Advancement of Science.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 5991 - Posted: 06.24.2010

Nanoparticles cause brain damage in fish, according to a study of the toxicity of synthetic carbon molecules called "buckyballs". The soccer-ball-shaped molecules show great promise in nanotechnology. But the preliminary study raises the possibility that nanomaterials could cause significant environmental harm, although much further work is needed to establish the extent of this risk. Eva Oberdýrster of Southern Methodist University in Dallas, US, who led the study, found modest concentrations of buckyballs in water caused significant harm to two aquatic animals. Water fleas were killed by the addition of the tiny carbon balls, and fish showed up to a 17-fold increase in brain damage compared with unexposed animals. © Copyright Reed Business Information Ltd.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 5204 - Posted: 06.24.2010

Industry, Environmentalists Argue Over How and When to Remove Toxic Metal By Guy Gugliotta WILSONVILLE, Ala. -- Larry Monroe pointed to a set of eight manhole cover-size plates mounted on the exhaust vent to limit mercury emissions from Gaston 3, a coal-burning power plant that feeds electricity to a half-dozen southern states. Gaston 3 and plants like it, the backbone of the U.S. power industry, are the focus of a furious debate over mercury pollution -- how much and how fast the nation should move to regulate a toxic metal capable of causing severe neurological damage, especially to fetuses and young children. Each of the plates at Gaston 3 houses an injector that squirts activated carbon dust into Gaston 3's flue gas. Particles of mercury cling to the carbon, which is then trapped by filters and discarded as toxic waste. © 2004 The Washington Post Company

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 4: Development of the Brain
Link ID: 5133 - Posted: 06.24.2010

Study of high-seafood diet points to poison's long-lasting impact. HELEN PEARSON Eating seafood that contains mercury can affect the brain development of children in their adolescence, according to a study of people in the Faroe Islands. The study fuels an ongoing debate about the health effects of a form of mercury called methylmercury, which accumulates in large marine animals such as swordfish and whales. Some researchers think these compounds are toxic only to babies as they develop in the womb, and that older children are unlikely to suffer developmental problems from the poison. © Nature News Service / Macmillan Magazines Ltd 2004

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 4: Development of the Brain
Link ID: 4932 - Posted: 06.24.2010

by Erik Ness Attention, parents: Now that you've seen your kids' first report cards of the year, it's time for a little homework of your own. No doubt you're doing the best you can to ensure your little ones' eventual membership in Mensa -- promoting stimulating dinner conversation, reading a chapter together each night, maybe even playing Mozart during bath time. But wait -- there's more. You'll find your next assignment in the pages of Colleen Moore's Silent Scourge: Children, Pollution, and Why Scientists Disagree. You probably already know that lead is not an appropriate component of any cerebral calisthenics program. But nor is it the only pollutant that can stunt intellectual development. In Silent Scourge, Moore, a developmental psychologist, reviews the case against lead and five additional types of pollutants -- mercury, PCBs, pesticides, noise, and radioactive and chemical wastes. With the possible exception of noise, most people recognize these pollutants as harmful and wouldn't actively incorporate them into K-12 curriculums or meal plans. But that doesn't mean we've got the necessary information -- or power -- to protect kids from them. Each of these pollutants has been the object of protracted debate, the kind of media-moderated, he-said/she-said dispute that frequently leaves us more worn down than wised up. Moore cuts through the confusion, using lay language to explain the dangers each pollutant poses to child development, including intellectual function, behavior, emotional state, and overall physical and psychological well-being. © 2003, Grist Magazine, Inc. All rights reserved.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 4735 - Posted: 06.24.2010

Survey finds mercury in 4 species at markets in Bay Area Jane Kay, Chronicle Environment Writer Four popular varieties of fish sold by high-end markets in the Bay Area contain toxic mercury at levels suspected of causing health problems, a Chronicle/CBS5 survey has found. Recent reports have raised new concerns about the mercury content of such big, ocean-caught fish as swordfish and tuna, including a study last year of local residents who ate fish several times a week. The Chronicle and CBS5 wanted to find out just how much mercury a consumer might be getting from fish sold at some of the Bay Area's best fish markets. The results underscore what many longtime fish lovers and health- conscious consumers may not completely understand -- that consuming large amounts of certain types of fish can jeopardize one's health. And for some people, particularly children and pregnant women, no amount of these fish would be safe. ©2003 San Francisco Chronicle

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 4: Development of the Brain
Link ID: 4590 - Posted: 06.24.2010

Susan Milius For the first time, scientists have found a poisonous frog that takes up a toxin from its prey and then tweaks the chemical to make it a more deadly weapon. At least three species of the 4-to-5-centimeter-long Dendrobates frogs of the New World tropics modify an alkaloid to create one that's about five times as poisonous, according to a team led by John W. Daly of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) in Bethesda, Md. The souped-up poison, one of a class called pumiliotoxins, ends up as a protective agent in the frogs' skin, the researchers report in an upcoming Proceedings of the National Academy of Sciences. "It's an important thing, showing how chemistry connects the life of one organism to another," comments chemical ecologist Jerrold Meinwald of Cornell University. Although scientists have found that some creatures other than frogs customize a basic toxin for various purposes, "I don't know of any other examples of improving a defensive weapon," Meinwald says. Copyright ©2003 Science Service.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 4224 - Posted: 06.24.2010

No clear choices on which fish are best Olivia Wu, Chronicle Staff Writer So you jack up the amount of fish you eat, pump the omega-3s, and make your heart healthier and happier than it's ever been. But at the same time, are you accumulating toxic levels of mercury and making a mess of your brain and nerves? It depends, scientists say. What kind of fish, how large the fish are and your individual tolerance for mercury are all factors in choosing a mercury-safe seafood diet. You can eat fish often -- if you choose carefully. ©2003 San Francisco Chronicle

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 4: Development of the Brain
Link ID: 3698 - Posted: 06.24.2010

SUZANNE GAMBOA, Associated Press Writer PST WASHINGTON (AP) -- Low levels of sarin nerve gas affected behavior and organ functions in laboratory animals at least a month after exposure, suggests new research that may provide clues to the mysterious illnesses of Persian Gulf War veterans. In separate Army-sponsored studies, scientists observed behavioral problems, brain changes and immune system suppression in the animals many days after exposure to doses that caused no immediate effects, such as convulsions or pupil constriction. Both studies involved rodents, and "that's a big leap to human beings," said Melinda Roberson, a behavioral neuroscientist involved in a study still under way. ©2002 Associated Press

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 3222 - Posted: 06.24.2010

Technique detects nerve agent's swift decay. KENDALL POWELL The deadly nerve agent VX degrades on concrete in a matter of hours, a new detector has revealed1. The finding could help military clean-up crews and chemical-weapons inspectors. The discovery was a surprise spin-off from a project to detect VX at Idaho National Engineering and Environmental Laboratory in Idaho Falls. The research group designed a sensitive instrument to detect VX's chemical signature on a contaminated surface. Chemist Gary Groenewold and his colleagues celebrated when they found that their device, called a secondary ion mass spectrometer, could pick up VX on a concrete sample at minute concentrations of around one part per million. They left to grab some lunch. © Nature News Service / Macmillan Magazines Ltd 2002

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 3137 - Posted: 06.24.2010

Copyright © 2002 AP Online By SHARON L. CRENSON, AP National Writer BURLINGTON, Vt. - A study of Californians who loaded their lunch and dinner menus with fish shows 89 percent wound up with elevated mercury levels in their bodies. The research, presented Saturday by San Francisco internist Dr. Jane Hightower at a symposium of environmental health experts in Vermont, is one of the first studies to document mercury levels in Americans who eat more fish than the Environmental Protection Agency recommends. Doctors are increasingly interested in the possible risks of eating too much mercury-tainted fish, and the Environmental Protection Agency and the Food and Drug Administration are trying to better inform the public about the subject. Copyright © 2001 Nando Media

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 2833 - Posted: 06.24.2010

Bespoke bacteria tackle poisonous organophosphates. HELEN PEARSON Bacteria could digest chemical-weapons stockpiles, say Californian chemists. Their genetically engineered bacteria might also scrub pesticides from farm equipment. A bin full of bugs could make a cheap, green bioreactor to break down residues left in agricultural aircraft, tractors or animal dips, says Ashok Mulchandani of the University of California in Riverside. Mulchandani and his colleagues have given Escherichia coli bacteria the power to break down organophosphates. Developed - but now banned - as chemical-warfare agents, the use of mild forms of these compounds as insecticides has led to concern that they may harm farm workers or contaminate food. © Nature News Service / Macmillan Magazines Ltd 2002

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 1861 - Posted: 06.24.2010

CHAPEL HILL ? Because of concerns about terrorists one day using such deadly nerve agents as sarin, soman, tabun and VX, a University of North Carolina at Chapel Hill scientist is urging the government and medical researchers to investigate potentially more effective treatments. Dr. David S. Janowsky says he has a strong candidate drug that might prevent many deaths from an attack. Studies he and colleagues published 16 years ago suggest scopolamine, a drug already routinely used to combat motion sickness, could be a significant improvement over the standard treatment, atropine, in treating civilians and military personnel exposed to toxic nerve agents. Copyright © 1992-2002 Bio Online, Inc. All rights reserved.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 1492 - Posted: 06.24.2010

A drug widely used to treat cancer may cause brain damage, with the effects lasting for years after the end of treatment, research suggests. The drug, 5-fluorouracil (5-FU), is used, alongside others, to treat cancers of the breast, ovaries, colon, stomach, pancreas and bladder. Tests on mice showed it destroys vital cells in the brain that help to keep nerves functioning properly. The University of Rochester study features in the Journal of Biology. The researchers say their findings could explain some of the neurological side effects associated with chemotherapy - a phenomenon often known as "chemo brain". These include memory loss, poor concentration, and in more extreme cases, seizures, impaired vision and even dementia. Until recently they were often dismissed as the by-products of fatigue, depression and anxiety related both to the diagnosis and treatment of cancer. But many patients show symptoms: a previous study by the Rochester team found more than 80% of breast cancer patients reported some form of mental impairment after chemotherapy. The latest study found 5-FU attacks oligodendrocyte cells in the brain and the precursor stem cells from which they originate. These cells play a crucial role in the central nervous system, producing myelin, the protective sheath that keeps nerve fibres in working order. If myelin is not constantly renewed, communication between nerve cells is damaged. The researchers showed that oligodendrocytes virtually disappeared from the brains of mice six months after the animals were treated with 5-FU. (C)BBC

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 11552 - Posted: 04.23.2008

An hour sniffing exhaust fumes may not just give you a headache - it could even alter the way the brain functions, Dutch researchers have suggested. Scientists have known nanoparticles reach the brain when inhaled, but this is the first time they have been shown to affect how we process information. Researchers sought to replicate the environment experienced by those who work in a garage or by the roadside. Their findings were published in the journal Particle and Fibre Toxicology. A team at Zuyd University in the Netherlands persuaded 10 volunteers to spend an hour in a room filled either with clean air or exhaust from a diesel engine. They were wired up to an electroencephalograph (EEG), a device that records the electrical signals of the brain. They were monitored during the period of exposure and for an hour after they left the room. After about 30 minutes, the brains of those in the exhaust rooms displayed a stress response on the EEG, which is indicative of a change in the way information is being processed in the brain cortex. This effect continued after they were no longer in the room. "We can only speculate what these effects may mean for the chronic exposure to air pollution encountered in busy cities where the levels of such soot particles can be very high," said lead researcher Paul Borm. "It is conceivable that the long-term effects of exposure to traffic nanoparticles may interfere with normal brain function and information processing. Further studies are necessary to explore this effect." The fact that the brain responds when confronted with a new smell is not entirely surprising, says Ken Donaldson, professor of respiratory toxicology at the University of Edinburgh. "And it may not necessarily be negative, but such physiological changes do warrant investigation because there could indeed be a long-term effect. It's a very interesting, and potentially important, study." (C)BBC

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 11401 - Posted: 03.11.2008

Agricultural workers exposed to high levels of pesticides have a raised risk of brain tumours, research suggests. The French study also indicated a possible higher risk among people who used pesticides on houseplants. All agricultural workers exposed to pesticides had a slightly elevated brain tumour risk, it suggested. But the Occupational and Environmental Medicine study found the risk was more than doubled for those exposed to the highest levels. The risk of a type of central nervous system tumour known as a glioma was particularly heightened among this group - more than three times the risk in the general population. Gliomas are more common in men than women, and the researchers speculate that part of the reason might be that men are more often exposed to pesticides. However, the overall risk of developing a brain tumour remained very low. UK experts said the findings were inconclusive. The findings were based on an analysis of 221 cases of brain tumours by the French Institute of Public Health, Epidemiology and Development. The research took place in the Bordeaux wine-growing region, where 80% of all pesticides used are fungicides. The chemicals are mixed and sprayed in a mist to protect vines from fungal attack. However, the researchers were unable to get specific enough data to pin down exactly which types of pesticide were associated with the development of brain tumours. (C)BBC

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 5: The Sensorimotor System
Link ID: 10375 - Posted: 06.05.2007

Two Howard Hughes Medical Institute research teams working independently have discovered new information about how the botulinum neurotoxin shuts down neurons with deadly efficiency. By providing detailed views of the toxin plugged into its neuronal receptor, the new studies could aid efforts to engineer specialized versions of the powerful neurotoxin that is used to treat a wide array of medical problems. The two groups were led by HHMI investigators Axel Brunger at Stanford University and Edwin Chapman at the University of Wisconsin at Madison. They published their findings December 13, 2006, in advance online publications in the journal Nature. "Botulinum neurotoxins are powerful tools for biologists and find widespread use as therapeutics for the treatment of certain nervous-system diseases," wrote Giampietro Schiavo of the London Research Institute in an accompanying News & Views commentary in Nature. "For these reasons, the papers reported here are of tremendous value." Botulinum neurotoxins are among the most deadly natural toxins in the world. They act by first attaching themselves to receptors on the surface of neurons. The toxins then insinuate an enzyme into the neuron that degrades key proteins required for neurons to communicate with one another. The toxins principally affect muscle-controlling motor neurons activated by the neurotransmitter acetylcholine. They kill by paralyzing the respiratory muscles. There are seven structurally and functionally related botulinum neurotoxins (BoNTs), called serotypes A through G, with each acting in a slightly different manner.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 9747 - Posted: 12.14.2006