Data from satellite sensors show that during the Northern Hemisphere’s growing season, the Midwest region of the United States boasts more photosynthetic activity than any other spot on Earth, according to NASA and university scientists.Healthy plants convert light to energy via photosynthesis, but chlorophyll also emits a fraction of absorbed light as fluorescent glow that is invisible to the naked eye. The magnitude of the glow is an excellent indicator of the amount of photosynthesis, or gross productivity, of plants in a given region.Research in 2013 led by Joanna Joiner, of NASA’s Goddard Space Flight Center in Greenbelt, Md., demonstrated that fluorescence from plants could be teased out of data from existing satellites, which were designed and built for other purposes. The new research led by Luis Guanter of the Freie Universitt Berlin, used the data for the first time to estimate photosynthesis from agriculture. Results were published March 25 in Proceedings of the National Academy of Sciences.According to co-author Christian Frankenberg of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., “The paper shows that fluorescence is a much better proxy for agricultural productivity than anything we’ve had before. This can go a long way regarding monitoring — and maybe even predicting — regional crop yields.”Guanter, Joiner and Frankenberg launched their collaboration at a 2012 workshop, hosted by the Keck Institute for Space Studies at the California Institute of Technology in Pasadena, to explore measurements of photosynthesis from space. The team noticed that on an annual basis, the tropics are the most productive. But during the Northern Hemisphere’s growing season, the U.S. Corn Belt “really stands out,” Frankenberg said. “Areas all over the world are not as productive as this area.”The researchers set out to describe the phenomenon observed by carefully interpreting the data from the Global Ozone Monitoring Experiment 2 (GOME-2) on Metop-A, a European meteorological satellite. Data showed that fluorescence from the Corn Belt, which extends from Ohio to Nebraska and Kansas, peaks in July at levels 40 percent greater than those observed in the Amazon.Comparison with ground-based measurements from carbon flux towers and yield statistics confirmed the results.The match between ground-based measurements and satellite measurements was a “pleasant surprise,” said Joiner, a co-author on the paper. …Read more
Despite their strong pro-family values, evangelical Christians have higher than average divorce rates — in fact, being more likely to be divorced than Americans who claim no religion, according to findings as cited by researchers from Baylor University.The research is part of a new report released by the Council on Contemporary Families.The council report coincides with the 50-year anniversary of the passage of the Civil Rights Act, which made it illegal to discriminate against individuals on the basis of race, national origin, religion or gender. The council’s report, which included findings by a dozen researchers, dealt with changes in the past half century for each of the populations affected by the law: religious groups, racial and ethnic minorities and women. Baylor’s portion of the report dealt with 50 years of religious change, from 1964 to 2014. Other findings included:• The proportion of Americans who do not identify with any religious tradition has grown dramatically — from 3 percent in the 1960s to 20 percent today — despite the fact that 90 percent of Americans professed a belief in God or a higher power.• Protestants have declined in their share of the American adult population, from 70 percent in the 1950s to a little less than 50 percent today.• The protracted decline in Protestant shares of the American population is largely due to the decline of Mainline Protestant denominations (e.g., Methodists, Lutherans and Episcopalians), whose numbers have halved over the same time period• Evangelicals rapidly increased their share of the population until the early 1990s, but that segment has experienced some decline since then.• The percentage of Catholics has remained steady, but their ethnic makeup has changed dramatically due to steady Latino immigration.• The proportion of people who affiliate with non-Judeo-Christian religions has doubled since the 1950s.Story Source:The above story is based on materials provided by Baylor University. Note: Materials may be edited for content and length.Read more
Scientists have for the first time sequenced an ancient RNA genome — of a barley virus once believed to be only 150 years old — pushing its origin back at least 2,000 years and revealing how intense farming at the time of the Crusades contributed to its spread.Researchers at the University of Warwick have detected and sequenced the RNA genome of Barley Stripe Mosaic Virus (BSMV) in a 750-year-old barley grain found at a site near the River Nile in modern-day Egypt. Their study is published in the journal Scientific Reports.This new find challenges current beliefs about the age of the BSMV virus, which was first discovered in 1950 with the earliest record of symptoms just 100 years ago.Although ancient DNA genomes have been sequenced before, ancient RNA genomes have not been as RNA breaks down more rapidly than DNA — generally around 50 times as fast.However in extremely dry conditions, such as those at the site in Qasr Ibrim in Lower Nubia where the barley was found, RNA can be better preserved and this has allowed the scientists to successfully sequence its genome.Using the new medieval RNA to calibrate estimates of the rate of mutations, the researchers were able to trace the evolution of the Barley Stripe Mosaic Virus to a probable origin of around 2,000 years ago, but potentially much further back to the domestication of barley in the Near East around 11,000 years ago.BSMV is transmitted through seed-to-seed contact so it is likely to originally have been transferred from the wild grass population to an early cultivated form of barley while the seeds were stored.Dr Robin Allaby of the School of Life Sciences at the University of Warwick, who led the study, said: “It is important to know as much as we can about virus evolution as emerging infectious plant diseases are a growing threat to global food security, and of those viruses account for almost half.”History tells us about the devastation caused by the emergence of disease from wild hosts in disparate countries, such as the Central American origin of the oomycete that led to the Irish potato famine.”We need to build up an accurate picture of the evolution of different types of virus so we can make better decisions about policies on plant movement.”The medieval RNA from Qasr Ibrim gives us a vital clue to unlock the real age of the Barley Stripe Mosaic Virus.”It is very difficult to understand how a plant disease evolved by solely relying on recent samples, however this 750-year-old example of the virus allows us to more accurately estimate its evolution rates and date of origin.”Without the Medieval RNA evidence, the virus appears to be much younger than it actually is, when in fact its origins go back thousands of years.”It’s possible that other viruses that similarly appear to be very recent may in fact have a more ancient origin.”The researchers believe that the Medieval BSMV genome came from a time of rapid expansion of the plant disease in the Near East and Europe.This coincided with the tumult of the Crusades which saw the Christian lands of Europe take arms against the Muslim territories of the Near East with their sights set on the city of Jerusalem. The seventh Crusade of Louis IX in 1234 is the most closely aligned in date to the origin of the virus expansion.The researchers believe the massive war effort could have caused the virus to spread, fuelled by an intensification of farming in order to feed the armies engaged in the campaign.This made contact with cultivated barley and wild grass more likely, providing opportunities for the virus to ‘jump’ into the crop.Genetic evidence also points to a split into an east and west BSMV lineage around the end of the 15th century, around 100 years after the Mongol Empire stabilised the Silk Road. It is likely that BSMV was transported to the east via trade routes such as the Silk Road in the late Medieval period.In more recent history, the virus appears to have spread to the US from Europe around 120-150 years ago.The research was supported by the research funding body BBSRC.Story Source:The above story is based on materials provided by University of Warwick. Note: Materials may be edited for content and length.Read more
Forests provide us with essential raw materials and the demand for these materials is increasing. To meet this increasing demand, forestry faces the challenge of how to intensify management of the existing production forests in sustainable ways.An international and multidisciplinary team of scientists led by Christian Levers from the Humboldt-Universitt in Berlin show that forest harvesting intensity is distributed unevenly across Europe and harvested timber volumes were mostly well below the increment. The spatial patterns of forest harvesting intensity were well explained by forest-resource related variables (i.e., the share of plantation species, growing stock, forest cover), site conditions (i.e., topography, accessibility), and country-specific characteristics, whereas socioeconomic variables were less important.The study provides concrete starting points for developing measures targeted at increasing regional wood supply from forests or lowering harvest pressure in regions where forests are heavily used.The research was carried out in the context of the Integrated Project “Visions of land use transitions in Europe” (VOLANTE) and supported by the European Commission and the Einstein Foundation Berlin.Story Source:The above story is based on materials provided by European Forest Institute. Note: Materials may be edited for content and length.Read more
It was climate that killed many of the large mammals after the latest Ice Age. But what more specifically was it with the climate that led to this mass extinction? The answer to this is hidden in a large number of sediment samples from around the Arctic and in the gut content from permafrozen woolly rhinos, mammoth and other extinct ice age mammals.It is a bit of a shift in paradigm Willerslev and co-workers publish in this week’s edition of the journal Nature. The common image of a light-brown grass-steppe dominating the northern hemisphere during the Ice Age does not hold any longer. The landscape was far more diverse and stable than today, and big animals like woolly rhino and mammoth fed on grasses and particularly on protein-rich forbs. But at the Last Glacial Maximum 25,000 — 15,000 years ago, at a time when the climate was at its coldest and driest, a major loss of plant diversity took place. The animals barely survived.After the Ice Age ended about 10,000 years ago it became warmer again. After the large reduction of plant diversity during the Last Glacial Maximum another kind of vegetation now appeared. One of the key food sources of the large mammals- the protein-rich forbs — did not fully recover to their former abundance. This likely proved fatal for species like woolly rhino, mammoth, and horse in Asia and North America. …Read more
Oct. 17, 2013 — In collaboration with international colleagues, a research group at Aarhus University has contributed to the compilation of the most comprehensive botanical data set to date. PhD student Naia Morueta-Holme and her supervisor, Professor Jens-Christian Svenning, Department of Bioscience, spearheaded the analysis that reveals where rare species are found in the New World (North and South America) and the factors that determine whether a region is dominated by widespread or rare species.”The study shows that especially California, Mexico, the Caribbean islands, parts of the Andes, the south of South America, and the region around Rio de Janeiro are dominated by rare species. This came as a surprise to us, because the regions are very different in terms of climate and vegetation type. They include habitats such as wet tropical rainforests, dry subtropical regions, and even deserts, tropical mountains, and cool temperate grasslands and forests,” says Professor Svenning.However, the studies show that consistent processes are driving the distribution of the plants.”There are two factors in particular that are important for the distribution of the rare species. Firstly, a stable climate with relatively small seasonal differences, where the climate has remained much the same for tens of thousands of years. Secondly, only small areas of habitat are involved. The species are unable to spread, but the stability nevertheless enables them to survive for long periods of time, and to develop and specialise in the same place,” explains Naia Morueta-Holme.In large areas in the north of North America, on the other hand, the seasons vary significantly, and there have been distinct climate changes between ice ages (glacials) and warm ages (interglacials). Widespread species are dominant here, either because they can withstand a wide range of climate conditions or because they are good at dispersing and can track changes in climate over time. They can thus spread over the large habitat areas available.Rare species threatened by climate changeIn terms of the dominance of rare species, the close link between the size of the habitat area and a stable climate is of great concern regarding the impact of human-induced climate changes now prevailing in these regions.”Even though we’re expecting less climate change in the areas dominated by rare species than in North America, for example, it could well be that future changes may be beyond what the species can tolerate. …Read more
Sep. 4, 2013 — A joint Australian-German research team led by Curtin University’s Dr Christian Hirt has created the highest-resolution maps of Earth’s gravity field to date — showing gravitational variations up to 40 per cent larger than previously assumed.Using detailed topographic information obtained from the US Space Shuttle, a specialist team including Associate Professor Michael Kuhn, Dr Sten Claessens and Moritz Rexer from Curtin’s Western Australian Centre for Geodesy and Professor Roland Pail and Thomas Fecher from Technical University Munich improved the resolution of previous global gravity field maps by a factor of 40.”This is a world-first effort to portray the gravity field for all countries of our planet with unseen detail,” Dr Hirt said.”Our research team calculated free-fall gravity at three billion points — that’s one every 200 metres — to create these highest-resolution gravity maps. They show the subtle changes in gravity over most land areas of Earth.”The new gravity maps revealed the variations of free-fall gravity over Earth were much bigger than previously thought.Earth’s gravitational pull is smallest on the top of the Huascaran mountain in the South American Andes, and largest near the North Pole.”Only a few years ago, this research would not have been possible,” Dr Hirt said.”The creation of the maps would have required about 80 years of office PC computation time but advanced supercomputing provided by the Western Australian iVEC facility helped us to complete the maps within a few months.”High-resolution gravity maps are required in civil engineering, for instance, for building of canals, bridges and tunnels. The mining industry could also benefit.”The maps can be used by surveyors and other spatial science professionals to precisely measure topographic heights with satellite systems such as the Global Positioning System (GPS),” Dr Hirt said.The findings of the research team from Curtin and Technical University Munich have recently appeared in the journal Geophysical Research Letters.Earth’s gravity field gallery: http://geodesy.curtin.edu.au/research/models/GGMplus/gallery.cfmRead more
July 14, 2013 — Building on earlier work exploring the complex choreography by which intricate cellular proteins interact with and copy DNA prior to cell division, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory and collaborators have captured a key step-molecular images showing how the enzyme that unwinds the DNA double helix gets drawn to and wrapped around its target. Details of the research, published in the journal Nature Structural & Molecular Biology, enhance understanding of an essential biological process and may suggest ways for stopping cell division when it goes awry.”This was truly collaborative work where molecular biology expertise from Christian Speck’s lab at Imperial College, London, Bruce Stillman’s group at Cold Spring Harbor Laboratory, and the cryo-electron microscopy expertise at Brookhaven were all essential,” said Huilin Li, a biologist at Brookhaven Lab and Stony Brook University and a lead author on the paper.”Our work is aimed at understanding the molecular details and mechanism of DNA replication at a fundamental level,” said Li, “But our findings could have important implications, possibly pointing to new ways to fight cancer, because irregularities in DNA duplication and uncontrolled cell division are hallmarks of the disease.”The current research picks up where a study conducted last year left off. That research determined the structure of a piece of protein machinery called the “origin recognition complex” (ORC), which identifies and binds to DNA-replication “start” sites. When joined by a replication initiation factor, the ORC undergoes conformational changes that set in motion the whole replication process. The new study reveals how this previous structure recruits and interacts with the enzyme that eventually unwinds the DNA double helix into two separate strands.”What we’ve uncovered in this study was a kind of missing link-what happens to this helicase enzyme before it encircles the DNA and starts unwinding the two strands,” Li said.Speck, Group Head at the MRC Research Institute in London, commented, “Our international collaboration has now revealed how the different protein components are assembled to generate a helicase loading complex. It is fascinating to see for the first time the architecture of this molecular machine.”Catching the molecular machinery in action is no simple task. Intermediate protein structures exist on fleeting timescales, and the interactions take place at the atomic level. Researchers working in Speck and Stillman’s labs used tools of molecular biology and biochemistry to slow down the process. They purified and then remixed together pieces of the protein puzzle (including the origin recognition complex, the replication initiator, the core of the helicase, and other components) and a slow-acting energy agent so the energy-requiring reaction is unable to proceed to completion. …Read more
July 1, 2013 — The forest we are used to looking at is not at all in equilibrium. Since the Ice Age, a number of plants have been ‘missing’ in Northern Europe, i.e. species that have not yet arrived. The same applies in many other parts of the world. Similarly, there is evidence that — even today — it often takes a very long time before plants follow when glaciers retreat, or the climate changes. In future, such disequilibrium will become the norm in the plant communities on Earth.This has been demonstrated by a new synthesis carried out by two researchers at Aarhus University — Professor of Biology Jens-Christian Svenning and Assistant Professor Brody Sandel.Professor Svenning explains: “In the climate debate, even researchers have had a tendency to overlook the fact that ecological dynamics can be slow. However, our forests take an extremely long time to adapt. For example, we still have a small amount of small-leaved lime in Denmark, which has held on since the warm period during the Bronze Age, i.e. about 3000 years. Perhaps it will now get another chance to spread when the summers once more get warmer. …Read more
June 21, 2013 — Researchers in Berlin and Munich, Germany and Oxford, United Kingdom, have revealed that a protein well known for its role in Alzheimer’s disease controls spindle development in muscle and leads to impaired movement in mice when the protein is absent or treated with inhibitors. The results, which are published in The EMBO Journal, suggest that drugs under development to target the beta-secretase-1 protein, which may be potential treatments for Alzheimer’s disease, might produce unwanted side effects related to defective movement.Share This:Alzheimer’s disease is the most common form of dementia found in older adults. The World Health Organization estimates that approximately 18 million people worldwide have Alzheimer’s disease. The number of people affected by the disease may increase to 34 million by 2025. Scientists know that the protein beta-secretase-1 or Bace1, a protease enzyme that breaks down proteins into smaller molecules, is involved in Alzheimer’s disease. Bace1 cleaves the amyloid precursor protein and generates the damaging Abeta peptides that accumulate as plaques in the brain leading to disease. Now scientists have revealed in more detail how Bace1 works.”Our results show that mice that lack Bace1 proteins or are treated with inhibitors of the enzyme have difficulties in coordination and walking and also show reduced muscle strength,” remarked Carmen Birchmeier, one of the authors of the paper, Professor at the Max-Delbrück-Center for Molecular Medicine in Berlin, Germany, and an EMBO Member. “In addition, we were able to show that the combined activities of Bace1 and another protein, neuregulin-1 or Nrg1, are needed to sustain the muscle spindles in mice and to maintain motor coordination.”Muscle spindles are sensory organs that are found throughout the muscles of vertebrates. They are able to detect how muscles stretch and convey the perception of body position to the brain. The researchers used genetic analyses, biochemical studies and interference with pharmacological inhibitors to investigate how Bace1 works in mice. …Read more
June 3, 2013 — Some research has shown that the effects of changes in the climate may be weak or even non-existent. This makes it easy to conclude that climate change will ultimately have less impact than previous warnings have predicted. But it could also be explained as direct and indirect effects cancelling each other out, as scientists from the University of Gothenburg, Sweden, show in a paper recently published in PNAS, the esteemed US scientific journal.To investigate how different climate impacts interact, an experiment was conducted at Kristineberg Marine Research Station.”We raised the water temperature in miniature ecosystems containing eelgrass meadows, while simultaneously bubbling with carbon-dioxide. This allowed us to simulate a future climate scenario, characterized by both warmer waters and ocean acidification”, explains researcher Christian Alsterberg.Eelgrass meadows grow in shallow coastal waters and are among the most productive ecosystems in the sea. These meadows are now threatened, not only by climate change but also by overfishing and eutrophication.”By studying eelgrass meadows on a ecosystem level, we were able to observe how plants and animals interact under changing climatic conditions. This also allowed us to measure the indirect effects, meaning the effects of climate change on an animal or a plant mediated through another organism.”For example, the metabolism of many crustaceans that live in eelgrass meadows increases when the water temperature rises. This in turn means they need to eat more algae and may consequently graze it more efficiently. At the same time, the growth of benthic microalgae on the sediment surface in the eelgrass meadows will be more vigorous.Using statistical methods that separates direct and indirect effects, the researchers were able to discern how higher water temperature combined with ocean acidification affects not just individual species but also interactions between species in the ecosystem.The researchers found that the effects are largely determined by the presence or absence of different fauna, primarily small algae-eating crustaceans. The net effect of changes in temperature and ocean acidification on benthic microalgae is non-existent if there are crustaceans in the ecosystem. But in the absence of crustaceans, the amount of benthic algae is largely controlled by positive and negative direct and indirect effects of higher temperatures and acidification.The results showed that, without small algae-eating crustaceans in the eelgrass meadows, climate change could pose a much greater threat to their survival.”The experiment also taught us the importance of investigating climate change using several different approaches, in order to fully understand its effects and to predict future impacts”, says Christian Alsterberg.Read more
May 30, 2013 — Researchers at the Stanford University School of Medicine have found that a naturally occurring protein secreted only in discrete areas of the mammalian brain may act as a Valium-like brake on certain types of epileptic seizures.
The protein is known as diazepam binding inhibitor, or DBI. It calms the rhythms of a key brain circuit and so could prove valuable in developing novel, less side-effect-prone therapies not only for epilepsy but possibly for anxiety and sleep disorders, too. The researchers’ discoveries will be published May 30 in Neuron.
“This is one of the most exciting findings we have had in many years,” said John Huguenard, PhD, professor of neurology and neurological sciences and the study’s senior author. “Our results show for the first time that a nucleus deep in the middle of the brain generates a small protein product, or peptide, that acts just like benzodiazepines.” This drug class includes not only the anti-anxiety compound Valium (generic name diazepam), first marketed in 1965, but its predecessor Librium, discovered in 1955, and the more recently developed sleep aid Halcyon.
Valium, which is notoriously addictive, prone to abuse and dangerous at high doses, was an early drug treatment for epilepsy, but it has fallen out of use for this purpose because its efficacy quickly wears off and because newer, better anti-epileptic drugs have come along.
For decades, DBI has also been known to researchers under a different name: ACBP. In fact, it is found in every cell of the body, where it is an intracellular transporter of a metabolite called acyl-CoA. “But in a very specific and very important brain circuit that we’ve been studying for many years, DBI not only leaves the cells that made it but is — or undergoes further processing to become — a natural anti-epileptic compound,” Huguenard said. “In this circuit, DBI or one of its peptide fragments acts just like Valium biochemically and produces the same neurological effect.”
Other endogenous (internally produced) substances have been shown to cause effects similar to psychoactive drugs. In 1974, endogenous proteins called endorphins, with biochemical activity and painkilling properties similar to that of opiates, were isolated. A more recently identified set of substances, the endocannabinoids, mimic the memory-, appetite- and analgesia-regulating actions of the psychoactive components of cannabis, or marijuana.
DBI binds to receptors that sit on nerve-cell surfaces and are responsive to a tiny but important chemical messenger, or neurotransmitter, called GABA. The roughly one-fifth of all nerve cells in the brain that are inhibitory mainly do their job by secreting GABA, which binds to receptors on nearby nerve cells, rendering those cells temporarily unable to fire any electrical signals of their own.
Benzodiazepine drugs enhance GABA-induced inhibition by binding to a different site on GABA receptors from the one GABA binds to. That changes the receptor’s shape, making it hyper-responsive to GABA. These receptors come in many different types and subtypes, not all of which are responsive to benzodiazepines. DBI binds to the same spot to which benzodiazepines bind on benzodiazepine-responsive GABA receptors. But until now, exactly what this means has remained unclear.
Huguenard, along with postdoctoral scholar and lead author Catherine Christian, PhD, and several Stanford colleagues zeroed in on DBI’s function in the thalamus, a deep-brain structure that serves as a relay station for sensory information, and which previous studies in the Huguenard lab have implicated on the initiation of seizures. The researchers used single-nerve-cell-recording techniques to show that within a GABA-secreting nerve-cell cluster called the thalamic reticular nucleus, DBI has the same inhibition-boosting effect on benzodiazepine-responsive GABA receptors as do benzodiazepines. Using bioengineered mice in which those receptors’ benzodiazepine-binding site was defective, they showed that DBI lost its effect, which Huguenard and Christian suggested makes these mice seizure-prone.
In another seizure-prone mouse strain in which that site is intact but the gene for DBI is missing, the scientists saw diminished inhibitory activity on the part of benzodiazepine-responsive GABA receptors. Re-introducing the DBI gene to the brains of these mice via a sophisticated laboratory technique restored the strength of the GABA-induced inhibition. In normal mice, a compound known to block the benzodiazepine-binding site weakened these same receptors’ inhibitory activity in the thalamic reticular nucleus, even in the absence of any administered benzodiazepines. This suggested that some naturally occurring benzodiazepine-like substance was being displaced from the benzodiazepine-binding site by the drug. In DBI-gene-lacking mice, the blocking agent had no effect at all.
Huguenard’s team also showed that DBI has the same inhibition-enhancing effect on nerve cells in an adjacent thalamic region — but also that, importantly, no DBI is naturally generated in or near this region; in the corticothalamic circuit, at least, DBI appears to be released only in the thalamic reticular nucleus. So, the actions of DBI on GABA receptors appear to be tightly controlled to occur only in specific brain areas.
Huguenard doesn’t know yet whether it is DBI per se, or one of its peptide fragments (and if so which one), that is exerting the active inhibitory role. But, he said, by finding out exactly which cells are releasing DBI under what biochemical circumstances, it may someday be possible to develop agents that could jump-start and boost its activity in epileptic patients at the very onset of seizures, effectively nipping them in the bud.Read more