In the latest British Medical Journal, Bob Roehr quoted Irving Weissman, the Stanford University researcher and president of the International Society for Stem Cell Research society as saying that the society launched a patient education website "to smoke out the charlatans" who prey upon desperately ill people and their families(BMJ 2010;340:c3271. This is a step in the right direction.
Dr Weissman, clarified that probably no other society has ever done this before. He was addressing the opening of their annual meeting on 16 June, in San Francisco.
Deveoloping countries are the preferred havens for the charlatans to prey on the gullible patients.
Bob Roehr argued that the problem is large and growing. He revealed that a recent web search identified more than 200 practitioners or clinics making claims for stem cell cures;, they thrive in developing countries obviously because regulatory oversight is weak in such countries. It is unbelievable that a clinic in China claimed to have treated over 8000 people, generating over $200m (£137m; 165m) in revenue.
It is difficult to arrest these activities. The scoiety felt that basic education about stem cells may help.The society’s new website, www.closerlookatstemcells.org, offers such material. According to the website a reputable clinical trial will have a body of scientific literature behind it; will be scrutinised by an independent review board; and will have the approval of the relevant national regulatory authorities. And it will not charge for participating in the trial.
The website allows a person to submit the name of a clinic for review. The society will then ask the clinic for documentation on ethical and regulatory review of the proposed treatment. That information will form a publicly available online database. It is not clear why a crook who is cashing on the misery of a victim should cooperate for such a review.
Bob Roehr quotes the case of a farmer who spent $80,000 for a stem cell "cure" for multiple sclerosis. An instance Dr Weissman found out while he gave a lecture in his home town, Great Falls, Montana, his hometown with a population of a little over 50 000. It is a pity that people mortgage their homes desperately seeking a cure where there is none.
The service offered by the society is laudable.Jeanne F Loring from the Scripps Research Institute a speker at th emeeting highlighted other issues. She pointed ouyt that patient testimonials are a hallmark of these operations. You will not see is any scientific evidence. There will be no guarantee that you will be helped by that treatment. Lastly,there are no guarantees that you won’t be harmed.
Clinics may use inappropriate treatment. According to the researcher, these clinics often use cord blood or placental cells, which may not be appropriate for the intended use. They may use cells derived from animals, or inject cell solutions that are tainted with other products.
Dr Loring suggested that if patients could procure a sample of the cells that are going to be injected, freeze them, and send them to her, she will analyse it for free and tell you what those stem cells are. This is indeed a generous offer.She can be contacted at jloring@scripps.edu
Regrettably, reporters of some popular newspapers in India unwittingly publicize the magic cures. They do not know the damage they are doing. They must resist the temptation; publish only those cures only if they appear in peer reviewed literature.
Saturday, June 19, 2010
Friday, June 18, 2010
Highly efficient solar cells could result from quantum dot research
Researchers from the University of Texas at Austin feel that they can enhance the limit of efficiency of currently available solar cells from 3o percent to 60 percent by converting the splar heat lost in the cells by a suitable design modification. They are confident that "there is no reason that we cannot be using solar energy 100 percent within 50 years."
The concept appears to be simple and straightforward; lot more work to advance the chemistry of semiconductor is needed to achieve the objective
K.S.Parthasarathy
EurekAlert! Public release date: 17-Jun-2010
Contact: Dr. Xiaoyang Zhu
zhu@cm.utexas.edu
512-471-9914
University of Texas at Austin
Highly efficient solar cells could result from quantum dot research
IMAGE: Xiaoyang Zhu and colleagues discovered that hot electrons can be transferred from photo-excited lead selenide nanocrystals to an electron conductor made of titanium dioxide. Their discovery points the way toward...
Click here for more information.
AUSTIN, Texas—Conventional solar cell efficiency could be increased from the current limit of 30 percent to more than 60 percent, suggests new research on semiconductor nanocrystals, or quantum dots, led by chemist Xiaoyang Zhu at The University of Texas at Austin.
Zhu and his colleagues report their results in this week's Science.
The scientists have discovered a method to capture the higher energy sunlight that is lost as heat in conventional solar cells.
The maximum efficiency of the silicon solar cell in use today is about 31 percent. That's because much of the energy from sunlight hitting a solar cell is too high to be turned into usable electricity. That energy, in the form of so-called "hot electrons," is lost as heat.
If the higher energy sunlight, or more specifically the hot electrons, could be captured, solar-to-electric power conversion efficiency could be increased theoretically to as high as 66 percent.
"There are a few steps needed to create what I call this 'ultimate solar cell,'" says Zhu, professor of chemistry and director of the Center for Materials Chemistry. "First, the cooling rate of hot electrons needs to be slowed down. Second, we need to be able to grab those hot electrons and use them quickly before they lose all of their energy."
Zhu says that semiconductor nanocrystals, or quantum dots, are promising for these purposes.
As for the first problem, a number of research groups have suggested that cooling of hot electrons can be slowed down in semiconductor nanocrystals. In a 2008 paper in Science, a research group from the University of Chicago showed this to be true unambiguously for colloidal semiconductor nanocrystals.
Zhu's team has now figured out the next critical step: how to take those electrons out.
They discovered that hot electrons can be transferred from photo-excited lead selenide nanocrystals to an electron conductor made of widely used titanium dioxide.
"If we take the hot electrons out, we can do work with them," says Zhu. "The demonstration of this hot electron transfer establishes that a highly efficient hot carrier solar cell is not just a theoretical concept, but an experimental possibility."
The researchers used quantum dots made of lead selenide, but Zhu says that their methods will work for quantum dots made of other materials, too.
He cautions that this is just one scientific step, and that more science and a lot of engineering need to be done before the world sees a 66 percent efficient solar cell.
In particular, there's a third piece of the science puzzle that Zhu is working on: connecting to an electrical conducting wire.
"If we take out electrons from the solar cell that are this fast, or hot, we also lose energy in the wire as heat," says Zhu. "Our next goal is to adjust the chemistry at the interface to the conducting wire so that we can minimize this additional energy loss. We want to capture most of the energy of sunlight. That's the ultimate solar cell.
"Fossil fuels come at a great environmental cost," says Zhu. "There is no reason that we cannot be using solar energy 100 percent within 50 years."
###
Funding for this research was provided by the U.S. Department of Energy. Coauthors include William Tisdale, Brooke Timp, David Norris and Eray Aydil from the University of Minnesota, and Kenrick Williams from The University of Texas at Austin.
Media contact: Lee Clippard, public affairs, 512-232-0675, lclippard@mail.utexas.edu
EurekAlert! ]
The concept appears to be simple and straightforward; lot more work to advance the chemistry of semiconductor is needed to achieve the objective
K.S.Parthasarathy
EurekAlert! Public release date: 17-Jun-2010
Contact: Dr. Xiaoyang Zhu
zhu@cm.utexas.edu
512-471-9914
University of Texas at Austin
Highly efficient solar cells could result from quantum dot research
IMAGE: Xiaoyang Zhu and colleagues discovered that hot electrons can be transferred from photo-excited lead selenide nanocrystals to an electron conductor made of titanium dioxide. Their discovery points the way toward...
Click here for more information.
AUSTIN, Texas—Conventional solar cell efficiency could be increased from the current limit of 30 percent to more than 60 percent, suggests new research on semiconductor nanocrystals, or quantum dots, led by chemist Xiaoyang Zhu at The University of Texas at Austin.
Zhu and his colleagues report their results in this week's Science.
The scientists have discovered a method to capture the higher energy sunlight that is lost as heat in conventional solar cells.
The maximum efficiency of the silicon solar cell in use today is about 31 percent. That's because much of the energy from sunlight hitting a solar cell is too high to be turned into usable electricity. That energy, in the form of so-called "hot electrons," is lost as heat.
If the higher energy sunlight, or more specifically the hot electrons, could be captured, solar-to-electric power conversion efficiency could be increased theoretically to as high as 66 percent.
"There are a few steps needed to create what I call this 'ultimate solar cell,'" says Zhu, professor of chemistry and director of the Center for Materials Chemistry. "First, the cooling rate of hot electrons needs to be slowed down. Second, we need to be able to grab those hot electrons and use them quickly before they lose all of their energy."
Zhu says that semiconductor nanocrystals, or quantum dots, are promising for these purposes.
As for the first problem, a number of research groups have suggested that cooling of hot electrons can be slowed down in semiconductor nanocrystals. In a 2008 paper in Science, a research group from the University of Chicago showed this to be true unambiguously for colloidal semiconductor nanocrystals.
Zhu's team has now figured out the next critical step: how to take those electrons out.
They discovered that hot electrons can be transferred from photo-excited lead selenide nanocrystals to an electron conductor made of widely used titanium dioxide.
"If we take the hot electrons out, we can do work with them," says Zhu. "The demonstration of this hot electron transfer establishes that a highly efficient hot carrier solar cell is not just a theoretical concept, but an experimental possibility."
The researchers used quantum dots made of lead selenide, but Zhu says that their methods will work for quantum dots made of other materials, too.
He cautions that this is just one scientific step, and that more science and a lot of engineering need to be done before the world sees a 66 percent efficient solar cell.
In particular, there's a third piece of the science puzzle that Zhu is working on: connecting to an electrical conducting wire.
"If we take out electrons from the solar cell that are this fast, or hot, we also lose energy in the wire as heat," says Zhu. "Our next goal is to adjust the chemistry at the interface to the conducting wire so that we can minimize this additional energy loss. We want to capture most of the energy of sunlight. That's the ultimate solar cell.
"Fossil fuels come at a great environmental cost," says Zhu. "There is no reason that we cannot be using solar energy 100 percent within 50 years."
###
Funding for this research was provided by the U.S. Department of Energy. Coauthors include William Tisdale, Brooke Timp, David Norris and Eray Aydil from the University of Minnesota, and Kenrick Williams from The University of Texas at Austin.
Media contact: Lee Clippard, public affairs, 512-232-0675, lclippard@mail.utexas.edu
EurekAlert! ]
Wednesday, June 2, 2010
Nottingham research leads to blood test for early detection of cancer
Public release date: 1-Jun-2010
Contact: Lindsay Brooke
lindsay.brooke@nottingham.ac.uk
44-115-951-5751
University of Nottingham
Nottingham research leads to blood test for early detection of cancer
The University of Nottingham spin-out company, Oncimmune Ltd, has developed a ground breaking blood test which will aid the detection of cancer as much as five years earlier than current testing methods such as mammography and CT scans. Physicians will know the result of their patient's test within one week of sending in a blood sample to Oncimmune.
Oncimmune has developed a new technique which replicates the cancer proteins that trigger the body's response to the disease and robotic technology to measure this response. This new technology (immuno-biomarkers) provides a significant advance in how early a cancer may be detected and is likely to change the current paradigm of diagnosis and treatment for most solid cancers such as lung, breast, ovarian, colon and prostate.
Based on the early work of John Robertson, a world renowned breast cancer specialist and Professor of Surgery in The University of Nottingham's Faculty of Medicine and Health Sciences, Oncimmune has successfully transferred this science into a reproducible commercial test. The test for lung cancer, EarlyCDT-Lung™ will be launched nationally in the USA this month followed by a launch in the UK early next year.
Geoffrey Hamilton-Fairley, Executive Chairman of Oncimmune, said: "We believe this test, along with the others we will launch in the next few years, will lead to a better prognosis for a significant number of cancer sufferers."
Initial research results were derived using blood samples from patients with breast cancer and a group of high risk women attending for annual mammography — which Professor Robertson had prospectively collected in Nottingham. All samples were obtained with fully informed consent as part of a study which had received approval from the appropriate ethics committee. In addition to identifying the signal in the blood of a percentage of women when they developed breast cancer the results also showed that the signal could be detected in some of the high-risk patients who had given blood samples for a number of years during their annual check up and before they were subsequently diagnosed with cancer. When these samples were run retrospectively by Professor Robertson he showed that the prototype assay test could have detected over half of these cancers up to four years before they were actually diagnosed. The work on lung cancer followed through a European Union grant which involved both The University of Nottingham and Oncimmune in a collaboration with a number of European partners.
Professor John Robertson said "I am very pleased that the initial exciting research data that we produced in the laboratories at The University of Nottingham a number of years ago have been translated by Oncimmune to the first of many tests that will help us identify cancer early. The support of the University at all levels, including past and present Vice-Chancellors, Deans of the Faculty of Medicine and Heads of School along with the University's Management Board has been essential. Some of the initial research work was supported by charitable funds and donations from patient groups. In the commercialisation of the technology there have been a number of individuals who have continued to believe in and financially support the goal of developing a blood test for the early detection of cancer without whom this technology would not have reached this milestone. It has been a long and at times very hard road in creating a robust commercial test and those involved have worked with exceptional diligence and tenacity and have given their unremitting support to achieve this."
A study involving researchers at the Mayo Clinic in the USA recorded similar results using blood samples from a study of CT scans to screen for lung cancer where antibodies were detected up to five years before the lung cancers were diagnosed. A number of other academic centres have reported similar results.
Oncimmune LTD was founded in 2003 to commercialise the technology developed in the laboratories of Professor Robertson. In 2006 the company set up a North American operation to validate and scale-up the test — trialling it on more than eight million assay "wells" from 80,000 patient samples.
The first early cancer detection test (EarlyCDT™) to launch will be the test for lung cancer (EarlyCDT-Lung) which has the potential to detect the early stages of lung cancer possibly up to five years before a tumour appears. The target population for this test are high-risk individuals such as long-term smokers and ex-smokers between the ages of 40 and 75. Additionally the test would be appropriate for people who have been exposed to other risk factors associated with the disease, for instance, environmental exposures such as radon, asbestos and extensive exposure to secondary smoke.
Under the guidance of Professor Robertson, The University of Nottingham has become a world leader in the field of autoimmunity in cancer. Using the technology developed by Oncimmune there is, for the first time, a reliable platform available for testing the autoimmune response to cancer and further research will allow validation of the test in other tumour areas such as lung, colon and ovarian cancer.
To support this, the University is to establish a Centre of Excellence for Autoimmunity in Cancer (CEAC) with Professor Robertson as the Director of Research. The new centre will foster collaborative research to: speed up the delivery of an autoantibody blood test for different types of cancer for clinical use; encourage other research in the area of autoimmunity in cancer; and continue the search for support technologies that have the potential to enhance the medical prognosis following a positive test result.
Professor David Greenaway, Vice-Chancellor of The University of Nottingham said: "The establishment of CEAC will provide state-of-the-art technologies to continue world leading research and development in the early detection of cancer using autoantibodies. The new centre will house a multi disciplinary research team working in partnership with international collaborators and Oncimmune. The research will provide additional test systems for the early diagnosis of a wide range of cancers which will have considerable impact within clinical medicine. The group's discovery science which has led to a novel set of biomarkers is providing new insights into the biology of cancer. Their basic, translational and clinical research is likely to contribute to a positive paradigm shift in our understanding of the early phases of cancer cell development as well as enhancement of the medical management of a wide range of cancer types."
Initially the test will be offered via primary care physicians and pulmonologists in the USA for high risk asymptomatic patients as well as patients who have indeterminate lung nodules. Oncimmune will bill private insurance companies as well as government-run Medicare Part B carriers on behalf of the patient.
###
More information can be found at: www.oncimmune.co.uk or www.oncimmune.com
Thursday, May 27, 2010
Tracing bees using radiotransmitters
Public release date: 26-May-2010
[ Print | E-mail | Share ] [ Close Window ]
Contact: Jen Laloup
jlaloup@plos.org
415-624-1220
Public Library of Science
Researchers learn about role of bees in tropical ecosystems using radio transmitters
A New York State Museum scientist is one of several researchers who have become the first to use tiny radio transmitters to track bees over long distances in a forest habitat, yielding new insight into the role of bees in tropical forest ecosystems. The bee study research conducted by Dr. Roland Kays, the Museum's curator of mammals, and the other scientists, was published in the online peer reviewed journal PLoS ONE on May 26th.
Armed with radio antennas, Kays and the other researchers worked at the Smithsonian Tropical Research Institute (STRI) in Panama City, Panama, to track unique signals from tiny transmitters glued to individual orchid bees. Although radar had been used to track bees in open areas, this is the first time it has been used in forested habitats. The research opens the door to future studies of bees in temperate forests, such as those in New York State.
Bees are important pollinators for plants worldwide. Pollination is critical for trees to make fruits and seeds, including domesticated edible fruits, as well as inedible species that are found in most New York State forest habitats. However, little is known about the movement of bees because they are so small and difficult to track.
Researchers, using helicopters, discovered that the orchid bees traveled surprisingly long distances, zipping through increasingly scarce patches of tropical forest as they moved pollen between rare flowers that grew miles apart.
"People disrupt plant pollination as they disturb and destroy tropical forests," said David Roubik, senior staff scientist at the Smithsonian. "Radio-tracking significantly improves our understanding of bees and the plants they pollinate. Now we can track orchid bees to get at the distances and spatial patterns involved—vital details which have completely eluded researchers in the past."
The researchers chose 17 iridescent blue-green orchid bees called Exaerete frontalis -- fairly common in the forest. They are larger than New York state honeybees but similar to some of the state's other large bumble bees. Roubik determined that Panama's orchid bees weigh only 0.6 grams without nectar in their stomachs.
"These bees easily carry a 300 mg radio transmitter glued on their backs," said Martin Wikelski, co-author of the research paper and director of the Max Planck Institute of Ornithology, professor at Princeton University and Smithsoian research associate. "By following the radio signals, we discovered that male orchid bees spent most of their time in small core areas, but could take off and visit areas farther away. One male even crossed over the shipping lanes in the Panama Canal, flying at least five kilometres, and returned a few days later."
In the past, researchers have struggled to determine the distances that bees travel, following individuals marked with paint between baits, or using radar, which doesn't work well when trees are in the way. "Carrying the transmitter could reduce the distance that the bees travel, but even if the flight distances we record are the minimum distances that these orchid bees can fly, they are impressive, long-distance movements," said Kays, who is also a research associate at STRI. "These data help to explain how orchids these bees pollinate can be so rare."
###
STRI, the U.S. Environmental Protection Agency, the New York State Museum and the National Geographic Society provided support for the bee study. Other co-authors are affiliated with the University of Arizona, Tucson; Cornell University and EcolSciences, Inc. In addition to hand tracking bees, Wikelski, Kays and colleagues have set up the Automated Radio Telemetry System on Barro Colorado Island (IS THIS IN PANAMA). The system is available to interested researchers and is capable of tracking up to 200 different animals, 24 hours a day, at any given time. A unit of the Smithsonian Institution, STRI furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. More information is available at www.stri.org.
Citation: Wikelski M, Moxley J, Eaton-Mordas A, Lo´ pez-Uribe MM, Holland R, et al. (2010) Large-Range Movements of Neotropical Orchid Bees Observed via Radio Telemetry. PLoS ONE 5(5): e10738. doi:10.1371/journal.pone.0010738
Funding: The study was supported by the US Environmental Protection Agency, New York State Museum, EcolSciences, Inc., Smithsonian Tropical Research Institute and the National Geographic Society. EcolSciences, as the only commercial company among the funding organizations, had a role in the analysis, decision to publish, and preparation of the manuscript through the involvment of David Moskowitz.
Competing Interests: David Moskowitz is employed by EcolSciences, who is a funder of this research. The employment of this author in a commercial company does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials, as detailed online in the guide for authors.
Contact:
Joanne Guilmette
Jguilmet@mail.nysed.gov
518/474-8730
PLEASE LINK TO THE SCIENTIFIC ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL goes live after the embargo ends): http://dx.plos.org/10.1371/journal.pone.0010738
Disclaimer
This title and abstract release refers to upcoming articles in PLoS ONE. The releases have been provided by the article authors and/or journal staff. Any opinions expressed in these are the personal views of the contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the release and article and your use of such information.
About PLoS ONE
PLoS ONE is the first journal of primary research from all areas of science to employ a combination of peer review and post-publication rating and commenting, to maximize the impact of every report it publishes. PLoS ONE is published by the Public Library of Science (PLoS), the open-access publisher whose goal is to make the world's scientific and medical literature a public resource.
--------------------------------------------------------------------------------
[ Print | E-mail | Share ] [ Close Window ]
New pathway to cheap insulin
This paper deserves wide publicity as it reveals a cheaper method of making insulin
K.S.Parthasarathy
Public release date: 26-May-2010
[ Print | E-mail | Share ] [ Close Window ]
Contact: Bastian Dornbach
bastian.dornbach@helmholtz-hzi.de
49-053-161-811-407
Helmholtz Association of German Research Centres
New pathway to cheap insulin
Researchers from Helmholtz Centre in Braunschweig, Germany, publish new and more efficient method to manufacture insulin
More than eight million diabetics live in Germany. Diabetes is not restricted to our prosperous society and the highest growth rates often occur in countries with aspiring economies such as in Asia. Worldwide, more than 285 million people suffer from this illness; with 50 million diabetics, India is the country with the most people affected by this disease. In Europe, Germany shows the highest prevalence in the population with twelve percent. In a German-Indo collaboration, researchers from the Helmholtz-Centre for Infection Research (HZI) in Braunschweig, Germany have now developed a new method to cheaply produce insulin for the treatment of diabetes. The group's results have now been published in the open access online research magazine Microbial Cell Factories. With this, all information is freely accessible for everyone and is not subject to patent law.
"As we did last year with an alternative protocol for the development of a hepatitis B vaccine, we again decided to use this way and make our knowledge available for everybody," says Ursula Rinas from the HZI, who chairs the German side of the project. Thus, people can access "insider-information" that makes it possible to cheaply produce medicine which in return can be affordable to people in developing countries.
The researchers wanted to develop a new procedure to increase the yield of an insulin precursor from which the actual insulin can be obtained, and in this way reduce costs. They found the yeast Pichia pastoris and modified the cells so that they produce the building block for insulin while growing on a special medium. The results were highly gratifying: "With our procedure, Pichia pastoris delivers high yields – twice as much as known before", says Ursula Rinas. "Already with few cells it is possible to produce a lot of the insulin precursor."
In the early 1980s, insulin was the first recombinant product approved by the FDA for human application. Today, human insulin is produced as recombinant protein, using two major routes. One route involves the production of the insulin precursor using the bacterium Escherichia coli as expression host with complex subsequent isolation, solubilization and refolding procedures. The other route involves the well-known baker's yeast Saccharomyces cerevisiae. The advantage of the latter route lies in the secretion of a soluble insulin precursor into the culture supernatant, making it easier for isolation and chemical modification. The newly described method from Ursula Rinas and her group also uses this route. The isolation of the precursor from the culture supernatant is only followed by enzymatic finishing. Insulin produced with this new method can be used normally and is identical to human insulin. Currently, the researchers are working on a method to produce a vaccine against dengue fever using the same system as described here.
For most people in developing countries medicine is too expensive. The purchasing of insulin in those countries is often cost prohibitive. Another problem is patent law that makes it impossible to recreate medicine and sell it at low prices. Once a patent has expired, as is the case with insulin, the so called generic drugs can be produced cheaply. Unfortunately, emerging nations very often lack the insider knowledge to produce those generics.
###
Original article: Application of simple fed-batch technique to high-level secretory production of insulin precursor using Pichia pastoris with subsequent purification and conversion to human insulin. Gurramkonda C, Polez S, Skoko N, Adnan A, Gabel T, Chugh D, Swaminathan S, Khanna N, Tisminetzky S, Rinas U. Microb Cell Fact. 2010 May 12;9(1):31. [Epub ahead of print]
--------------------------------------------------------------------------------
[ Print | E-mail | Share ] [ Close Window ]
Wednesday, May 26, 2010
Lowly termite, not the lion or elephant, may be the star of Africa's savanna
It is an interesting observation. Termites are more important to the ecosystem that huge animals
K S Parthasarathy
Lowly termite, not the lion or elephant, may be the star of Africa's savanna
GAINESVILLE, Fla. --- The majestic animals most closely associated with the African savanna -- fierce lions, massive elephants, towering giraffes – may be relatively minor players when it comes to shaping the ecosystem.
The king of the savanna appears to be the termite, say ecologists who've found that these humble creatures contribute mightily to grassland productivity in central Kenya via a network of uniformly distributed colonies. Termite mounds greatly enhance plant and animal activity at the local level, while their even distribution over a larger area maximizes ecosystem-wide productivity.
The finding, published this week in the journal PLoS Biology, affirms a counterintuitive approach to population ecology: Often, it's the small things that matter most.
"One of the kind of typical things I think that people think about is, what drives a savanna in terms of its structure and function?" said Todd Palmer, one of the paper's authors and an assistant professor of biology at the University of Florida."We think about big animals, but these termites are having a massive impact on the system from below."
Said Robert M. Pringle, a research fellow at Harvard University and the lead author, "As (famed biologist) E.O. Wilson likes to point out, in many respects it's the little things that run the world."
Prior research on the Kenya dwarf gecko initially drew Pringle's attention to the peculiar role of grassy termite mounds, which in this part of Kenya are some 30 feet in diameter and spaced some 180 to 300 feet apart. Each mound teems with millions of termites, who build the mounds over the course of centuries.
After observing unexpectedly high numbers of lizards in the vicinity of mounds, Pringle, Palmer and their colleagues began to quantify ecological productivity relative to mound density. They found that each mound supported dense aggregations of flora and fauna: Plants grew more rapidly the closer they were to mounds, and animal populations and reproductive rates fell off appreciably with greater distance.
What was observed on the ground was even clearer in satellite imagery. Each mound – relatively inconspicuous on the Kenyan grassland – stood at the center of a burst of floral productivity. More important, these bursts were highly organized in relation to one another, evenly dispersed as if squares on a checkerboard. The result is an optimized network of plant and animal output closely tied to the ordered distribution of termite mounds.
"In essence, the highly regular spatial pattern of fertile mounds generated by termites actually increases overall levels of ecosystem production. And it does so in such a profound way," Palmer said. "Seen from above, the grid-work of termite mounds in the savanna is not just a pretty picture. The over-dispersion, or regular distribution of these termite mounds, plays an important role in elevating the services this ecosystem provides."
The mechanism through which termite activity is transformed into far-reaching effects on the ecosystem is a complex one. Pringle and Palmer suspect termites import coarse particles into the otherwise fine soil in the vicinity of their mounds. These coarser particles promote water infiltration of the soil, even as they discourage disruptive shrinking and swelling of topsoil in response to precipitation or drought.
The mounds also show elevated levels of nutrients such as phosphorus and nitrogen. All this beneficial soil alteration appears to directly and indirectly mold ecosystem services far beyond the immediate vicinity of the mound.
While further studies will explore the mechanism through which these spatial patterns of termite mounds emerge, Pringle and Palmer suggest that the present work has implications beyond the basic questions of ecology.
"Termites are typically viewed as pests, and as threats to agricultural and livestock production," Pringle said. "But productivity – of both wild and human-dominated landscapes – may be more intricately tied to the pattern-generating organisms of the larger natural landscape than is commonly understood."
###
Pringle and Palmer's co-authors on the PLoS Biology paper are Daniel F. Doak of the Mpala Research Centre and the University of Wyoming; Alison K. Brody of the Mpala Research Centre and the University of Vermont; and Rudy Jocqué of the Royal Museum for Central Africa in Tervuren, Belgium. Their work was supported by the Sherwood Family Foundation and the National Science Foundation.
K S Parthasarathy
Lowly termite, not the lion or elephant, may be the star of Africa's savanna
GAINESVILLE, Fla. --- The majestic animals most closely associated with the African savanna -- fierce lions, massive elephants, towering giraffes – may be relatively minor players when it comes to shaping the ecosystem.
The king of the savanna appears to be the termite, say ecologists who've found that these humble creatures contribute mightily to grassland productivity in central Kenya via a network of uniformly distributed colonies. Termite mounds greatly enhance plant and animal activity at the local level, while their even distribution over a larger area maximizes ecosystem-wide productivity.
The finding, published this week in the journal PLoS Biology, affirms a counterintuitive approach to population ecology: Often, it's the small things that matter most.
"One of the kind of typical things I think that people think about is, what drives a savanna in terms of its structure and function?" said Todd Palmer, one of the paper's authors and an assistant professor of biology at the University of Florida."We think about big animals, but these termites are having a massive impact on the system from below."
Said Robert M. Pringle, a research fellow at Harvard University and the lead author, "As (famed biologist) E.O. Wilson likes to point out, in many respects it's the little things that run the world."
Prior research on the Kenya dwarf gecko initially drew Pringle's attention to the peculiar role of grassy termite mounds, which in this part of Kenya are some 30 feet in diameter and spaced some 180 to 300 feet apart. Each mound teems with millions of termites, who build the mounds over the course of centuries.
After observing unexpectedly high numbers of lizards in the vicinity of mounds, Pringle, Palmer and their colleagues began to quantify ecological productivity relative to mound density. They found that each mound supported dense aggregations of flora and fauna: Plants grew more rapidly the closer they were to mounds, and animal populations and reproductive rates fell off appreciably with greater distance.
What was observed on the ground was even clearer in satellite imagery. Each mound – relatively inconspicuous on the Kenyan grassland – stood at the center of a burst of floral productivity. More important, these bursts were highly organized in relation to one another, evenly dispersed as if squares on a checkerboard. The result is an optimized network of plant and animal output closely tied to the ordered distribution of termite mounds.
"In essence, the highly regular spatial pattern of fertile mounds generated by termites actually increases overall levels of ecosystem production. And it does so in such a profound way," Palmer said. "Seen from above, the grid-work of termite mounds in the savanna is not just a pretty picture. The over-dispersion, or regular distribution of these termite mounds, plays an important role in elevating the services this ecosystem provides."
The mechanism through which termite activity is transformed into far-reaching effects on the ecosystem is a complex one. Pringle and Palmer suspect termites import coarse particles into the otherwise fine soil in the vicinity of their mounds. These coarser particles promote water infiltration of the soil, even as they discourage disruptive shrinking and swelling of topsoil in response to precipitation or drought.
The mounds also show elevated levels of nutrients such as phosphorus and nitrogen. All this beneficial soil alteration appears to directly and indirectly mold ecosystem services far beyond the immediate vicinity of the mound.
While further studies will explore the mechanism through which these spatial patterns of termite mounds emerge, Pringle and Palmer suggest that the present work has implications beyond the basic questions of ecology.
"Termites are typically viewed as pests, and as threats to agricultural and livestock production," Pringle said. "But productivity – of both wild and human-dominated landscapes – may be more intricately tied to the pattern-generating organisms of the larger natural landscape than is commonly understood."
###
Pringle and Palmer's co-authors on the PLoS Biology paper are Daniel F. Doak of the Mpala Research Centre and the University of Wyoming; Alison K. Brody of the Mpala Research Centre and the University of Vermont; and Rudy Jocqué of the Royal Museum for Central Africa in Tervuren, Belgium. Their work was supported by the Sherwood Family Foundation and the National Science Foundation.
Monday, December 21, 2009
Boston University reseachers develop faster, cheaper DNA sequencing method
Researchers have found a new method of DNA sequencing which is claimed to be cheaper and faster than the method used so far.In the method developed by them one needs onle a smaller quantity of DNA thereby eliminating the expensive, time-consuming and error-prone step of DNA amplification.By boosting capture rates by a few orders of magnitude, and reducing the volume of the sample chamber the researchers reduced the number of DNA molecules required by a factor of 10,000 – from about 1 billion sample molecules to 100,000.
K.S.Parthasarathy
Public release date: 20-Dec-2009
Contact: Mike Seele
mseele@bu.edu
617-353-9766
Boston University College of Engineering
Boston University researchers develop faster, cheaper DNA sequencing method
IMAGE: A team of researchers led by Boston University biomedical engineer Amit Meller is using electrical fields to efficiently draw long strands of DNA through nanopore sensors, drastically reducing the number...
Click here for more information.
(BOSTON) EMBARGOED UNTIL 1 P.M. EST 12/20/09 -- Boston University biomedical engineers have devised a method for making future genome sequencing faster and cheaper by dramatically reducing the amount of DNA required, thus eliminating the expensive, time-consuming and error-prone step of DNA amplification.
In a study published in the Dec. 20 online edition of Nature Nanotechnology, a team led by Boston University Biomedical Engineering Associate Professor Amit Meller details pioneering work in detecting DNA molecules as they pass through silicon nanopores. The technique uses electrical fields to feed long strands of DNA through four-nanometer-wide pores, much like threading a needle. The method uses sensitive electrical current measurements to detect single DNA molecules as they pass through the nanopores.
"The current study shows that we can detect a much smaller amount of DNA sample than previously reported," said Meller. "When people start to implement genome sequencing or genome profiling using nanopores, they could use our nanopore capture approach to greatly reduce the number of copies used in those measurements."
Currently, genome sequencing utilizes DNA amplification to make billions of molecular copies in order to produce a sample large enough to be analyzed. In addition to the time and cost DNA amplification entails, some of the molecules – like photocopies of photocopies – come out less than perfect. Meller and his colleagues at BU, New York University and Bar-Ilan University in Israel have harnessed electrical fields surrounding the mouths of the nanopores to attract long, negatively charged strands of DNA and slide them through the nanopore where the DNA sequence can be detected. Since the DNA is drawn to the nanopores from a distance, far fewer copies of the molecule are needed.
Before creating this new method, the team had to develop an understanding of electro-physics at the nanoscale, where the rules that govern the larger world don't necessarily apply. They made a counterintuitive discovery: the longer the DNA strand, the more quickly it found the pore opening.
"That's really surprising," Meller said. "You'd expect that if you have a longer 'spaghetti,' then finding the end would be much harder. At the same time this discovery means that the nanopore system is optimized for the detection of long DNA strands -- tens of thousands basepairs, or even more. This could dramatically speed future genomic sequencing by allowing analysis of a long DNA strand in one swipe, rather than having to assemble results from many short snippets.
"DNA amplification technologies limit DNA molecule length to under a thousand basepairs," Meller added. "Because our method avoids amplification, it not only reduces the cost, time and error rate of DNA replication techniques, but also enables the analysis of very long strands of DNA, much longer than current limitations."
With this knowledge in hand, Meller and his team set out to optimize the effect. They used salt gradients to alter the electrical field around the pores, which increased the rate at which DNA molecules were captured and shortened the lag time between molecules, thus reducing the quantity of DNA needed for accurate measurements. Rather than floating around until they happened upon a nanopore, DNA strands were funneled into the openings.
By boosting capture rates by a few orders of magnitude, and reducing the volume of the sample chamber the researchers reduced the number of DNA molecules required by a factor of 10,000 – from about 1 billion sample molecules to 100,000.
###
The research was funded by the National Human Genome Research Institute of the Institutes of Health and by the National Science Foundation. The article, "Electrostatic Focusing of Unlabelled DNA into Nanoscale Pores Using a Salt Gradient," will be available at the Nature web site beginning Dec. 20 at 1 p.m. at http://dx.doi.org/10.1038/natureNNANO.2009.379.
K.S.Parthasarathy
Public release date: 20-Dec-2009
Contact: Mike Seele
mseele@bu.edu
617-353-9766
Boston University College of Engineering
Boston University researchers develop faster, cheaper DNA sequencing method
IMAGE: A team of researchers led by Boston University biomedical engineer Amit Meller is using electrical fields to efficiently draw long strands of DNA through nanopore sensors, drastically reducing the number...
Click here for more information.
(BOSTON) EMBARGOED UNTIL 1 P.M. EST 12/20/09 -- Boston University biomedical engineers have devised a method for making future genome sequencing faster and cheaper by dramatically reducing the amount of DNA required, thus eliminating the expensive, time-consuming and error-prone step of DNA amplification.
In a study published in the Dec. 20 online edition of Nature Nanotechnology, a team led by Boston University Biomedical Engineering Associate Professor Amit Meller details pioneering work in detecting DNA molecules as they pass through silicon nanopores. The technique uses electrical fields to feed long strands of DNA through four-nanometer-wide pores, much like threading a needle. The method uses sensitive electrical current measurements to detect single DNA molecules as they pass through the nanopores.
"The current study shows that we can detect a much smaller amount of DNA sample than previously reported," said Meller. "When people start to implement genome sequencing or genome profiling using nanopores, they could use our nanopore capture approach to greatly reduce the number of copies used in those measurements."
Currently, genome sequencing utilizes DNA amplification to make billions of molecular copies in order to produce a sample large enough to be analyzed. In addition to the time and cost DNA amplification entails, some of the molecules – like photocopies of photocopies – come out less than perfect. Meller and his colleagues at BU, New York University and Bar-Ilan University in Israel have harnessed electrical fields surrounding the mouths of the nanopores to attract long, negatively charged strands of DNA and slide them through the nanopore where the DNA sequence can be detected. Since the DNA is drawn to the nanopores from a distance, far fewer copies of the molecule are needed.
Before creating this new method, the team had to develop an understanding of electro-physics at the nanoscale, where the rules that govern the larger world don't necessarily apply. They made a counterintuitive discovery: the longer the DNA strand, the more quickly it found the pore opening.
"That's really surprising," Meller said. "You'd expect that if you have a longer 'spaghetti,' then finding the end would be much harder. At the same time this discovery means that the nanopore system is optimized for the detection of long DNA strands -- tens of thousands basepairs, or even more. This could dramatically speed future genomic sequencing by allowing analysis of a long DNA strand in one swipe, rather than having to assemble results from many short snippets.
"DNA amplification technologies limit DNA molecule length to under a thousand basepairs," Meller added. "Because our method avoids amplification, it not only reduces the cost, time and error rate of DNA replication techniques, but also enables the analysis of very long strands of DNA, much longer than current limitations."
With this knowledge in hand, Meller and his team set out to optimize the effect. They used salt gradients to alter the electrical field around the pores, which increased the rate at which DNA molecules were captured and shortened the lag time between molecules, thus reducing the quantity of DNA needed for accurate measurements. Rather than floating around until they happened upon a nanopore, DNA strands were funneled into the openings.
By boosting capture rates by a few orders of magnitude, and reducing the volume of the sample chamber the researchers reduced the number of DNA molecules required by a factor of 10,000 – from about 1 billion sample molecules to 100,000.
###
The research was funded by the National Human Genome Research Institute of the Institutes of Health and by the National Science Foundation. The article, "Electrostatic Focusing of Unlabelled DNA into Nanoscale Pores Using a Salt Gradient," will be available at the Nature web site beginning Dec. 20 at 1 p.m. at http://dx.doi.org/10.1038/natureNNANO.2009.379.
Subscribe to:
Posts (Atom)