Climate change threatens trout

Climate change threatens trout

JAMES COOK UNIVERSITY

"Valuable fishery species such as coral trout could be under long-term threat." Image:Tammy616/iStockphoto Scientists are concerned that the impact of climate change on reef fishes is greater than first thought. Behavioural changes found in small fishes such as damselfish has highlighted concern that valuable fishery species such as coral trout could be under long-term threat. James Cook University’s Professor Philip Munday recently discovered that ocean acidification, specifically declines in pH caused by the addition of carbon dioxide (CO2), led to significant behavioural changes in damselfish and anemone fish, which left them open to predation. Researchers from the Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies and JCU had already found that many coral reef fishes would be vulnerable to environmental and habitat changes due to climate change. “Coral reefs are extremely vulnerable to sustained and ongoing climate change, mainly because of the temperature sensitivities of reef-building corals,” the project’s chief investigator, JCU’s Dr Morgan Pratchett said. “But climate change not only threatens the corals that build reefs, but the animals that live on coral reefs, including many different fishes.” Professor Munday said increased ocean acidification interfered with the ability of small prey fishes to distinguish potential predators through smell. “The effects of ocean acidification on the behaviour of reef fishes are much more striking than any of us had thought possible,” he said. Dr Pratchett said the evidence showed it was high time for greater understanding of how climate change impacted on fisheries species, such as coral trout. “This is an important step in demonstrating the potential economic ramifications of climate change,” he said. The commercial value of coral trout alone was $40 million in Queensland, notwithstanding the social and recreational value for the community. JCU is working with Queensland Department of Employment, Economic Development and Innovation (DEEDI) to assess if climate change’s impact on the Great Barrier Reef would improve or cause a decline in wild stocks of coral trout. Dr Pratchett and DEEDI fisheries biologist Adam Reynolds will be working closely with colleagues during the two-year project. The project, funded by the Fisheries Research and Development Corporation (FRCD) through the National Climate Change Adaptation Research Plan, is directly testing environmental sensitivities of coral trout during reproduction, fertilization and early development. “This project will be fundamental in understanding the threat of climate change on coral trout, but will also be important for assessing the aquaculture potential of this species,” Dr Pratchett said.

‘Woody weeds’ good for soil

‘Woody weeds’ good for soil

THE UNIVERSITY OF NEW SOUTH WALES

'Woody plants' is seen as a problem because they reduce grass cover. Image: pojbic/iStockphoto The global spread of native trees and shrubs into open grazing land and abandoned farms can bring unexpected environmental and economic benefits, a major new international study has found. While many landholders have a negative view of these so-called "woody weeds" because they reduce grass cover, the study found new evidence that they also improve soil health and provide important habitat for native animals. Woody plants are likely to increase and become more prominent with rising concentrations of atmospheric carbon dioxide, says Associate Professor David Eldridge, who led the study published in the journal Ecology Letters. The research team also involved scientists from Spain and the US. "Climate change will probably result in even more encroachment of shrubs and trees than we have seen already," says Professor Eldridge, of the UNSW School of Biological, Earth and Environmental Sciences. "This is seen as a problem by graziers because woody plants can hamper sheep mustering and reduce grass cover. "But our findings demolish the view that encroachment equates with degradation. "Landuses such as wildlife conservation, timber harvesting, ecotourism and carbon sequestration will be the big winners under an environment of denser woody plants." The researchers reviewed information in 244 published and unpublished scientific reports from around the world, revealing a far more complex and more positive picture. They looked a wide range of factors linked to woody plant encroachment, including grass cover, available soil phosphorus, soil organic carbon and above-ground carbon. Surprisingly, perhaps, they found that increasing shrub density makes little difference to most of those attributes. Some of those that do change, however, hold out hope of significant environmental and economic benefits. "Research has shown, for example, that dense stands of shrubs are substantial sinks for atmospheric carbon dioxide," Professor Eldridge says. Credits gained from large carbon sinks could provide financial benefits to rural communities under dedicated carbon-trading programs." In Australia, large areas of semi-arid woodland are now occupied by native shrubs growing more densely than before European settlement. The study found that areas dominated by shrubs have less grass but healthier soils, with more soil carbon and nitrogen, and more above-ground plant material. "The studies show that these shrubs provide habitat for many birds, insects and mammals, such as marsupial mice. "Although dense shrubs can create problems for some pastoralists in drier areas of NSW, other landholders are encouraging the natural spread of shrubs and trees to restore degraded environments and improve soil health."

Reindeers need ultraviolet light

Reindeers need ultraviolet light

THE UNIVERSITY OF WESTERN AUSTRALIA

"This adaptation in reindeer allowed them to find food and escape predators in light conditions that would challenge other mammals." Image:moori/iStockphoto The unexpected finding that Arctic reindeer avoid the damaging effects of ultra violet light that causes snow blindness in humans by allowing UV light to pass into the eye, contrasts with most other mammals including humans where UV light is prevented from entering the eye by the cornea and lens. Winthrop Professor David Hunt, a member of The University of Western Australia's Neuroecology Group in the School of Animal Biology, said this adaptation in reindeer allowed them to find food and escape predators in light conditions that would challenge other mammals. Professor Hunt is co-author with colleagues from institutions including University College London, the University of Tromsø in Norway and Moorfields Eye Hospital in London, of a paper published in the Journal of Experimental Biology today in which it is suggested that UV vision is vital to the reindeer's survival. For the reindeer, it means that vision is extended into the UV spectrum, which is important since many objects that absorb UV have high contrast against the highly reflective snow surface.  So the reindeer with its specially adapted eye can see a main source of food - lichen - as well as its main predator, the wolf with its white fur that also absorbs strongly in the UV and therefore appears dark to the reindeer against the white snow. "What remains uncertain however is how the retina in the reindeer is protected against the damaging effects of the UV light that penetrates the eye". Professor Hunt is a highly cited expert with more than 200 publications about vision which include studies in humans and other primates, birds, marsupials and fish. UV sensitivity is rare among placental mammals although more common in marsupials, and is certainly absent in humans but was known from Professor Hunt's previous research to be present in parrots: the budgerigar and African grey.  In other recent work published inProceedings of the Royal Society, Professor Hunt studied representatives from all the long-lived parrots - South American macaws, Caribbean amazons, Indonesian and Australian cockatoos, the Australian rosella and the New Zealand kea - in all, a total of 14 species.  In every case, the findings indicated that UV-sensitivity was present. "We humans wear sunglasses to protect our eyes from UV rays but this is not a luxury that is available to a reindeer or a parrot," Professor Hunt said."  The ability to see into the UV means that the world is coloured differently to a reindeer or a parrot.  For the parrot, it may be useful for foraging for food or for selecting a mate.  A parrot's feathers strongly reflect UV light so what looks dull to us may look very bright and enticing to a mate." The reindeer research was funded by Britain's Biotechnology and Biological Sciences Research Council.

Maths model improves brain diagnosis

Maths model improves brain diagnosis

GRIFFITH UNIVERSITY

With this mathematical model, an MRI scanner can segment and measure different tissue classes. Image: GA161076/iStockphoto The ability to obtain accurate measurement of different brain tissues from MRI scan imagery is a step closer as Griffith University develops new technology. Associate Professor Alan Liew from the School of Information, Communication Technology, has been working on computational algorithms which are important in the clinical diagnosis of brain conditions such as Alzheimer's and Parkinson's Disease. Using this mathematical model, an MRI scanner can be used to accurately segment and measure different tissue classes. The data can then be used by a clinician as a diagnostic tool to compare the brain tissue of healthy patients.  "These computations will allow the accurate quantitative measurement of tissue volume, such as the brain's grey matter which is important for memory and other cognitive processes and is relevant to conditions including Alzheimer's," Associate Professor Liew said.  Currently there is no way for a clinician to accurately obtain this information from an MRI scanning device.  "By using these algorithms, the clinician will be able to obtain quantitative measurements that can help both predict and monitor the rate of potential disease progression in designated increments." The research continues Associate Professor Liew’s development work which began in 2003 and was the focus of a 2010 $150,000 ARC Discovery Grant. Although the technique has not yet been perfected and is currently undergoing further refinement, Associate Professor Liew said the ability for clinicians to use the technology in hospitals as a diagnostic tool is potentially only a few years away. "Medical practitioners will not only have the opportunity to be able to plan patient treatment in advance for conditions such as Alzheimer’s and Parkinson's, but there will also be other applications for the technology such as in the study of sleep disorders," he said. Preliminary research into this area has also shown that the computational modelling can be used to study MRI scans which can ascertain the brain tissue differences present in people with sleep disorders. "Without the ability to obtain accurate measurements of the brain tissues by using these algorithms, again this type of comparison would not be possible," Associate Professor Liew said.

Time for a New Focus on Food

Time for a New Focus on Food

JULIAN CRIBB

Civil wars over food in northern Africa at a time when around half of Australians are dying as a result of their diets present the greatest scientific challenge of our time. Few people seem to have noticed that two governments went belly-up in North Africa recently – as a result of riots that began as protests over the price of food. Food insecurity is growing worldwide as demand for food grows and the things we need to produce it – land, water, oil, nutrients, fish, technology and stable climates – become more scarce. At the same time around half of Australians are dying as a result of their diets, at enormous cost to those that live. Now is the time to think hard and creatively about the solution to this double-edged dilemma, which is arguably the greatest scientific challenge of our time. Here are some places we can start. Rehydrate, revegetate, recarbonise: we need a national plan to rebuild the fertility, carbon content, vegetation cover and water retention of our landscapes. This could harvest rainfall currently lost to evaporation and help proof us against climate change. Recycle, re-nourish: we also need a national plan to harvest fresh water and nutrients as they pass through our great cities and return them to food production in industries both traditional and entirely new – such as algae farming, hydroponics and biocultures. Re-energise: the next oil crisis is on the way and Australia is totally unprepared. We need new, renewable energy sources for agriculture and transport, such as algal biodiesel, second-generation biofuels, hydrogen fuel cells, solar electrics or boron ion batteries. And we need them yesterday. Reinvest: we need massive reinvestment in agricultural science, technology and extension, to counter two decades of neglect and policy failure. Priority areas for science include: unifying organic and high-intensity farming thinking to create a new eco-agriculture that uses fewer resources, wastes less and produces more; improved irrigation and water use efficiency; a new focus on soil microbiology to enhance crop and pasture yields sustainably; developing novel food systems (rural and urban) that are cushioned against climate shocks; frontier science, such as re-engineering the photosynthetic pathways of crops and trees to boost yields and lock up more carbon; and designing novel, healthier diets and foods to replace the high fat-salt-sugar-dye regime imposed by the global food processing sector. Share knowledge: Australia will not be secure if food security in Asia collapses. We need to build a new multi-billion dollar knowledge export industry based on our expertise in areas such as land care, dryland farming, water management and drought strategy. Retrain: our agricultural education system is falling apart and is in desperate need of renewal. We need to train a new generation of farmer and urban food producers equipped to solve the scarcities ahead. We need our best and brightest to find careers in a field central to the destiny of civilisation this century. Re-educate Australians about food: up to half of all Australian food is wasted or sent to landfill. Young Australians are “digging their graves with their teeth” through unhealthy diets. We should lead a global endeavour to educate our children to eat healthily, sustainably and with a renewed respect for food. This can be assisted by introducing a Food Year in every junior school in Australia, teaching all subjects through the lens of food. Reinvest in farming: massive global re­investment is needed to head off food scarcity in the mid-century – yet farm profitability and productivity are falling. The current global economic signal, caused by massive concentration of market power off-farm, tells farmers to “grow less”. This adverse signal must be changed to stimulate the essential investment – for example, through a GST on food paid directly to farmers to protect soil, water, wildlife, atmosphere and landscapes. If Australia can successfully tackle challenges such as these, we will lead the world in helping to secure the global food supply.

இனப்படுகொலை குற்றவாளி மிலாடிக் ஐ.நா.பாதுகாப்பில் நெதர்லாந்தில் தனிச்சிறையில் தடுத்து வைப்பு!

இனப்படுகொலை குற்றவாளி மிலாடிக் ஐ.நா.பாதுகாப்பில் நெதர்லாந்தில் தனிச்சிறையில் தடுத்து வைப்பு!

National Geographic Channel strikes again...mind blowing!               <

How to make a human neuron

Researchers have worked out how to reprogram cells from human skin into functioning nerve cells.

Ewen Callaway

Working neurons have been created from human skin cells

By transforming cells from human skin into working nerve cells, researchers may have come up with a model for nervous-system diseases and perhaps even regenerative therapies based on cell transplants.

The achievement, reported online today in Nature¹, is the latest in a fast-moving field called transdifferentiation, in which cells are forced to adopt new identities. In the past year, researchers have converted connective tissue cells found in skin into heart cells², blood cells³ and liver cells⁴.

Transdifferentiation is an alternative to the cellular reprogramming that involves converting a mature cell into a pluripotent stem cell — one capable of becoming many types of cell — then coaxing the pluripotent cell into becoming a particular type of cell, such as neurons. Marius Wernig, a stem-cell researcher at Stanford University in California, and the leader of the study, says that skipping the pluripotency step could avoid some of the problems of making tissues from these induced pluripotent stem cells (iPSCs). The pluripotency technique can also take months to complete.

Wernig's team sparked the imaginations of cellular reprogrammers last year, when it transformed cells taken from the tip of a mouse's tail into working nerve cells⁵. That feat of cellular alchemy took just three foreign genes – delivered into tail cells with a virus – and less than two weeks. "We thought that as it worked so great for the mouse, it should be no problem to work it out in humans," Wernig says. "That turned out to be wrong."

Not quite right

Those three genes also made human cells that looked like nerve cells but that did not fire the electric pulses characteristic of neurons. However, the addition of a fourth virus-delivered gene, found through trial and error, pushed fibroblast cells — connective tissue cells found throughout the body and involved in wound healing — collected from aborted fetuses and the foreskin of newborns to become bona fide neurons. After a couple of weeks in culture, many of the neurons responded to electric jolts by pumping ions across their membranes. A few weeks later still, these neurons started to form connections, or synapses, with the mouse neurons they were grown alongside.

There are still kinks to work out, Wernig admits. Only 2–4% of the fibroblasts became neurons — lower than the roughly 8% efficiency his team achieved with the mouse tail cells. And most of the resulting neurons communicated using a chemical called glutamate, limiting their use for understanding or treating diseases such as Parkinson's, which is characterized by problems in neurons that communicate with this chemical.

Wernig says that his team expects their efficiency to improve and is trying to make neurons that communicate using other chemicals.

Quick success

Neurons forged through transdifferentation offer advantages over brain cells made from iPSCs, says Evan Snyder, a stem-cell biologist at the Sanford Burnham Medical Research Institute in San Diego, California. As well as being quicker to make, they are less likely to form tumours when they are implanted into tissue, he says.

On the downside, however, cellular signs of disease may only appear when a cell develops naturally, from a pluripotent stem cell into a differentiated neuron, Snyder says. Forcing a cell into becoming a neuron could cause scientists to miss aspects of a disease. Furthermore, the fibroblasts that are the starting material for transdifferentiation do not divide as readily as iPSCs, limiting their use in applications that require lots of cells, such as drug screening, Wernig says.

"I would say that both approaches should be actively pursued because you never know for which cases and specific applications one or the other may be more suitable," Wernig concludes. 

• References

  1. Pang, Z. P. et al. Nature advance online publication doi:10.1038/nature10202 (2011).
  2. Ieda, M. et al. Cell 142, 375-386 (2010). | Article | PubMed | ISI | ChemPort |
  3. Szabo, E. et al. Nature 468, 521-526 (2010). | Article | PubMed | ISI | ChemPort |
  4. Huang, P. et al. Nature advance online publication doi:10.1038/nature10116 (2011).
  5. Vierbuchen, T. et al. Nature 463, 1035-1041 (2010). | Article | PubMed | ISI | ChemPort |

Source: Nature
http://www.nature.com/news/2011/110526/full/news.2011.328.html?WT.ec_id=NEWS-20110531

 

Posted by
Robert Karl Stonjek

Sitting--- The real KILLER

Religious Experiences Shrink Part of the Brain

Religious Experiences Shrink Part of the Brain

A study links life-changing religious experiences, like being born again, with atrophy in the hippocampus

By 

 Religion changes the brain. Image: Roger Branch

The article, “Religious factors and hippocampal atrophy in late life,” by Amy Owen and colleagues at Duke University represents an important advance in our growing understanding of the relationship between the brain and religion. The study, published March 30 in PLoS One, showed greater atrophy in the hippocampus in individuals who identify with specific religious groups as well as those with no religious affiliation. It is a surprising result, given that many prior studies have shown religion to have potentially beneficial effects on brain function, anxiety, and depression.

A number of studies have evaluated the acute effects of religious practices, such as meditation and prayer, on the human brain. A smaller number of studies have evaluated the longer term effects of religion on the brain. Such studies, like the present one, have focused on differences in brain volume or brain function in those people heavily engaged in meditation or spiritual practices compared to those who are not. And an even fewer number of studies have explored the longitudinal effects of doing meditation or spiritual practices by evaluating subjects at two different time points.

In this study, Owen et al. used MRI to measure the volume of the hippocampus, a central structure of the limbic system that is involved in emotion as well as in memory formation. They evaluated the MRIs of 268 men and women aged 58 and over, who were originally recruited for the NeuroCognitive Outcomes of Depression in the Elderly study, but who also answered several questions regarding their religious beliefs and affiliation. The study by Owen et al. is unique in that it focuses specifically on religious individuals compared to non-religious individuals. This study also broke down these individuals into those who are born again or who have had life-changing religious experiences.

The results showed significantly greater hippocampal atrophy in individuals reporting a life-changing religious experience. In addition, they found significantly greater hippocampal atrophy among born-again Protestants, Catholics, and those with no religious affiliation, compared with Protestants not identifying as born-again.

The authors offer the hypothesis that the greater hippocampal atrophy in selected religious groups might be related to stress. They argue that some individuals in the religious minority, or those who struggle with their beliefs, experience higher levels of stress. This causes a release of stress hormones that are known to depress the volume of the hippocampus over time. This might also explain the fact that both non-religious as well as some religious individuals have smaller hippocampal volumes.

This is an interesting hypothesis. Many studies have shown positive effects of religion and spirituality on mental health, but there are also plenty of examples of negative impacts. There is evidence that members of religious groups who are persecuted or in the minority might have markedly greater stress and anxiety as they try to navigate their own society. Other times, a person might perceive God to be punishing them and therefore have significant stress in the face of their religious struggle. Others experience religious struggle because of conflicting ideas with their religious tradition or their family. Even very positive, life-changing experiences might be difficult to incorporate into the individual’s prevailing religious belief system and this can also lead to stress and anxiety. Perceived religious transgressions can cause emotional and psychological anguish. This “religious” and “spiritualpain” can be difficult to distinguish from pure physical pain. And all of these phenomena can have potentially negative effects on the brain.

Thus, Owen and his colleagues certainly pose a plausible hypothesis. They also cite some of the limitations of their findings, such as the small sample size. More importantly, the causal relationship between brain findings and religion is difficult to clearly establish. Is it possible, for example, that those people with smaller hippocampal volumes are more likely to have specific religious attributes, drawing the causal arrow in the other direction? Further, it might be that the factors leading up to the life-changing events are important and not just the experience itself. Since brain atrophy reflects everything that happens to a person up to that point, one cannot definitively conclude that the most intense experience was in fact the thing that resulted in brain atrophy. So there are many potential factors that could lead to the reported results. (It is also somewhat problematic that stress itself did not correlate with hippocampal volumes since this was one of the potential hypotheses proposed by the authors and thus, appears to undercut the conclusions.) One might ask whether it is possible that people who are more religious suffer greater inherent stress, but that their religion actually helps to protect them somewhat. Religion is frequently cited as an important coping mechanism for dealing with stress.

This new study is intriguing and important. It makes us think more about the complexity of the relationship between religion and the brain. This field of scholarship, referred to as neurotheology, can greatly advance our understanding of religion, spirituality, and the brain. Continued studies of both the acute and chronic effects of religion on the brain will be highly valuable. For now, we can be certain that religion affects the brain--we just are not certain how.

Are you a scientist? And have you recently read a peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter  @garethideas.

GOLD CROWN FOR BABA @ SHIRDI SAI MANDIR, CHANDIGARH~ U/L BY ANIL BHALLA