Thursday, April 30, 2009

Undiscovered Country


Who says there's nothing new under the sun? Botanist Mats Thulin of Uppsala University in Sweden and his colleagues have discovered a new tree that covers hillsides across some 3,000 square miles (8,000 square kilometers) on the border between Ethiopia and Somalia, a region known as Ogaden. The new tree—dubbed Acacia fumosa—has delicate pink flowers but persists in a region that has been torn by strife for years. "There are certainly more new species of plant to be discovered in Ogaden and in other parts of the world, but the existence of another unknown tree dominating the vegetation over such a large area is highly unlikely," botanist David Mabberley of the Royal Botanic Gardens in Kew, England, writes in this week'sScience.

Friday, April 24, 2009

Pesticide Exposure Found To Increase Risk Of Parkinson's Disease

ScienceDaily (Apr. 22, 2009) — The fertile soil of California's Central Valley has long made it famous as one of the nation's prime crop-growing regions. But it's not just the soil that allows for such productivity. Crops like potatoes, dry beans and tomatoes have long been protected from bugs and weeds by the fungicide maneb and the herbicide paraquat.
Scientists know that in animal models and cell cultures, such pesticides trigger a neurodegenerative process that leads to Parkinson's disease. Now, researchers at UCLA provide the first evidence for a similar process in humans.
In a new epidemiological study of Central Valley residents who have been diagnosed with Parkinson's disease, researchers found that years of exposure to the combination of these two pesticides increased the risk of Parkinson's by 75 percent. Further, for people 60 years old or younger diagnosed with Parkinson's, earlier exposure had increased their risk for the disease by as much as four- to six-fold.
Reporting in the April 15 issue of the American Journal of Epidemiology, Beate Ritz, professor of epidemiology at the UCLA School of Public Health, and Sadie Costello, a former doctoral student at UCLA who is now at the University of California, Berkeley, found that Central Valley residents who lived within 500 meters of fields sprayed between 1974 and 1999 had a 75-percent increased risk for Parkinson's.
In addition, people who were diagnosed with Parkinson's at age 60 or younger were found to have been at much higher risk because they had been exposed to maneb, paraquat or both in combination between 1974 and 1989, years when they would have been children, teens or young adults.
The researchers enrolled 368 longtime residents diagnosed with Parkinson's and 341 others as a control group.
Parkinson's disease is a degenerative disorder of the central nervous system that often impairs motor skills, speech and other functions. It has been reported to occur at high rates among farmers and in rural populations, contributing to the hypothesis that agricultural pesticides may be partially responsible.
Until now, however, data on human exposure has been unavailable, largely because it has been too hard to measure an individual's environmental exposure to any specific pesticide.
"Because pesticides applied from the air or ground may drift from their intended treatment sites — with measurable concentrations subsequently detected in the air, in plants and in animals up to several hundred meters from application sites — accurate methods of estimating environmental exposures in rural communities have long been sorely needed," said Ritz, the study's senior author and vice chair of the School of Public Health's epidemiology department.
So Ritz, Costello and colleague Myles Cockburn from the University of Southern California, developed a geographic information system–based tool that estimated human exposure to pesticides applied to agricultural crops. This GIS tool combined land-use maps and pesticide-use reporting data from the state of California. Each pesticide-use record includes the name of the pesticide's active ingredient, the amount applied, the crop, the acreage of the field, the application method and the date of application.
Research subjects were recruited between 1998 to 2007; telephone interviews were conducted to obtain their demographic and exposure information. Detailed residential history forms were mailed to subjects in advance of their interviews and were reviewed in person or over the phone. The researchers recorded and added lifetime residential histories and estimated ambient exposures into the system for all historical addresses at which participants had resided between 1974 and 1999, the period covered by the pesticide-use data.
"The results confirmed two previous observations from animal studies," Ritz said. "One, that exposure to multiple chemicals may increase the effect of each chemical. That's important, since humans are often exposed to more than one pesticide in the environment. And second, that the timing of exposure is also important."
Ritz noted that this is the first epidemiological study to provide strong evidence that maneb and paraquat act synergistically to become neurotoxic and strongly increase the risk of Parkinson's disease in humans.
Of particular concern, Ritz said, and consistent with other theories regarding the progression of Parkinson's pathology, is that the data "suggests that the critical window of exposure to toxicants may have occurred years before the onset of motor symptoms when a diagnosis of Parkinson's is made."
In addition to Ritz and first author Costello, study authors included Jeff Bronstein, UCLA professor of neurology, and Xinbo Zhang of USC. The authors declare no conflicts of interest.
The research was supported by the National Institute of Environmental Health Science, the National Institute of Neurological Disorders and Stroke, and the Department of Defense Prostate Cancer Research Program. In addition, initial pilot funding was provided by the American Parkinson Disease Association.
Journal reference:
Sadie Costello, Myles Cockburn, Jeff Bronstein, Xinbo Zhang, and Beate Ritz. Parkinson's Disease and Residential Exposure to Maneb and Paraquat From Agricultural Applications in the Central Valley of California. American Journal of Epidemiology, 2009; 169 (8): 919 DOI: 10.1093/aje/kwp006
Adapted from materials provided by University of California - Los Angeles. Original article written by Mark Wheeler.

Tuesday, April 21, 2009

Small Carnivores (Ecological Study) In Planted Forest Zone

Speaker: Miss Eng I Sum

Date: 25th April 2009 (Saturday)

Time: 2.00 to 4.00pm (registration 2.00-2.30pm)

Venue : New World 3, Level 5
New World Suite Bintulu

Admission Free

The speaker, Miss Eng I Sum is a graduate student of Universiti Tunku Abdul Rahman. She took
her Bachelor Degree of Science (Hons) in Biotechnology and currently pursuing her master study
at the same university. Her research is on habitat use of small carnivore in Malaysia with emphasis on microhabitat analysis and population size. The fine-scale habitat features, which is known as microhabitat, is species-specific because each species has a preferred microhabitat to survive and reproduce. Analyzing the microhabitat of small carnivores is useful to predict the potential portion of a habitat of a given species is more likely to occur. Also, by using the capture-recapture method, the population size of the small carnivores can be estimated. All of this information will provide a baseline data for future conservation work of small carnivores.

Wednesday, April 8, 2009

Tiniest Frog In South America's Andes Mountains


Tiniest Frog In South America’s Andes Mountains
ScienceDaily (Apr. 6, 2009) — It fits on a fingertip: Noblella pygmaea is a midget frog, the smallest ever found in the Andes and among the smallest amphibians in the world. Only its croaking was to be heard from the leaves on the mossier ground of the “elfin forests” in the highlands of Manu National Park, before German and Peruvian herpetologists discovered the tiny little thing in south-eastern Peru.

The popular name of the new species is fitting: Noble’s Pygmy Frog has an average length of 11.4 millimeters. It was introduced in a paper recently published in the journal Copeia by Edgar Lehr, a German herpetologist at the Senckenberg Natural History Collection Dresden, and the Swiss-Peruvian ecologist Alessandro Catenazzi from the University of California at Berkeley, USA. The pygmy that fits on a fingertip was discovered during field work in the Wayqecha Research Station. Not only its small size left it undiscovered for so long. Its predominantly brown colour camougflages Noblella perfectly. But Noble’s Pygmy Frog could be spotted with the assistance of the members of the native communities adjacent to the Manu National Park.
Manu National Park is well known as “hotspot” in the lowland rainforests, a place of exuberant diversity; however the biosphere reserve also preserves vast areas of montane cloud forests, where the sempiternal mists envelop and often conceal plants and animals. In the countless ecological niches many of them were able to evolve undisturbed and are highly adapted to the cold and permanently humidity at a daily average temperature of 11° Celsius. Genetic studies show that the diversity of amphibians in general and especially in this region is highly underestimated. That is why Edgar Lehr and Alessandro Catenazzi think that Noblella pygmaea is only one of many undiscovered amphibians in the Andes mountain area. The scientists expect to find other new species during the next few years.
Currently the midget frog is one of the smallest vertebrates ever found above 3000 metres, where most species tend to be larger than congeneric or similar species in lowland areas. Noblella pygmaea inhabits the cloud forest, the montane scrub and the high-elevation grasslands at a height from 3025 to 3190 metres above sea level. Beside its size the remarkably long forefinger is a notable distinguishing feature that was not found at other pygmy frogs in the mountains of Peru. The females lay only two eggs of approximately four millimeter in diameter. In contrast to most amphibian species these eggs are laid in moist, terrestrial microhabitats, such as in moss or leave litter, and are protected from insect predators by the mother frog. It is noteworthy also that embryos do not change into aquatic tadpoles, but immediately after the hatching lead a fully terrestrial life.
Whilst the scientists cannot give a reason for Noblella’s minute size, it is apparently advantageous. Maybe it is perfectly adopted to its special niche. The fact, that the species is not forced to leave its habitat – not even for egg deposition – might protect it from natural enemies. Despite living in the Manu Biosphere Reserve the survival of the midget frog and of other amphibians is uncertain. Several adverse influences such as anthropogenic habitat changes and the effects of global warming, which among other things facilitates the dispersal of the highly virulent pathogenic fungus Batrachochytrium dendrobatidis threaten amphibians of the Andean region. Fotunately the fungus, which has become epidemic, has not been noticed on Noblella so far. Possibly because of its terrestrial life Noblella is less exposed to the fungus than stream-dwelling frogs.
Batrachochytrium dendrobatidis is suspected to be the cause of the extinction of many frog species in Ecuador and northern Peru and is currently decimating populations of high-elevation frogs in southern Peru. Up to now no effective means are known for stopping the expansion of fungal infections in the region. Researchers hope that the large topographic heterogeneity of the Andes cordilleras will provide refugia where the fungus is unable to cause massive population declines in amphibian species, thus ensuring the survival of the dwarf in the Andean "elfin forests."

Wednesday, April 1, 2009

Pesticide & Birth Defects

Month Of Conception Linked To Birth Defects In United States

ScienceDaily (Mar. 30, 2009) — A study published in the April 2009 issue of the medical journal Acta P├Ždiatrica is the first to report that birth defect rates in the United States were highest for women conceiving in the spring and summer.

The researchers also found that this period of increase risk correlated with increased levels of pesticides in surface water across the United States.Studying all 30.1 million births which occurred in the U.S. between 1996 and 2002, the researchers found a strong association between the increased number of birth defects in children of women whose last menstrual period occurred in April, May, June or July and elevated levels of nitrates, atrazine and other pesticides in surface water during the same months.

While many of these chemicals, including the herbicide atrazine which is banned in European countries but permitted in the U.S., are suspected to be harmful to the developing embryo, this is the first study to link their increased seasonal concentration in surface water with the peak in birth defects in infants conceived in the same months.

The correlation between the month of last menstrual period and higher rates of birth defects was statistically significant for half of the 22 categories of birth defects reported in a Centers for Disease Control database from 1996 to 2002 including spina bifida, cleft lip, clubfoot and Down's syndrome."Elevated concentrations of pesticides and other agrochemicals in surface water during April through July coincided with significantly higher risk of birth defects in live births conceived by women whose last menstrual period began in the same months.

While our study didn't prove a cause and effect link, the fact that birth defects and pesticides in surface water peak during the same four months makes us suspect that the two are related," said Paul Winchester, M.D., Indiana University School of Medicine professor of clinical pediatrics, the first author of the study.

"Birth defects, which affect about 3 out of 100 newborns in the U.S., are one of the leading causes of infant death. What we are most excited about is that if our suspicions are right and pesticides are contributing to birth defect risk, we can reverse or modify the factors that are causing these lifelong and often very serious medical problems," said Dr. Winchester, a Riley Hospital for Children neonatalogist.

Birth defects are known to be associated with risk factors such as alcohol, smoking, diabetes or advanced age. However, the researchers found that even mothers who didn't report these risk factors had higher overall birth defect rates for babies conceived from April to July.

The study relies on findings by U.S. Geological Survey, the U.S. Environmental Protection Agency and other agencies on the seasonal variations in nitrates, atrazine and other pesticides in the surface water."These observations by Dr. Winchester are extremely important, as they raise the question for the first time regarding the potential adverse effect of these commonly used chemicals on pregnancy outcome – the health and well-being of our children," said James Lemons, M.D., Hugh McK. Landon Professor of Pediatrics at the IU School of Medicine.

Dr. Lemons is director of the section of neonatal-perinatal medicine at Riley Hospital.Co-authors of this study, which was funded by the Division of Neonatalogy of the Department of Pediatrics of the IU School of Medicine, were Jordan Huskins, B.A., a fourth year I.U. School of Medicine student, and Jun Ying, Ph.D. of the University of Cincinnati