#Could this gene make leafy greens last longer? Scientists have identified the process in plants that controls how quickly leaves die which may lead to lettuce that stays fresh in the fridge a little longer.
In a series of experiments using the plant Arabidopsis thaliana researchers discovered a key regulator S3h that acts as a brake on the process of leaf death
which is known as senesce. When its levels are low leaves senesce early; when it is present in high levels it results in longer leaf longevity.
It was serendipity we weren't actually looking for this gene but it turned up in an earlier survey of genes involved in leaf senesce says Su-Sheng Gan professor of horticulture at Cornell University.
When we characterized it we found more than we were looking for: a key step in the plant's pathway for controlling senescence that had been eluding scientists.
At the start of that pathway is salicylic acid precursor of the active ingredient in aspirin which is used by plants as a hormone to trigger development
and to fire up a response to a pathogen attack. The gene product they discovered breaks down salicylic acid effectively silencing the molecular command to die.
In addition to affecting the timing of leaf death it also affects its rate: While normal plants take more than nine days for a leaf to progress from living green to yellow plants without the gene yellowed in fewer than three days.
Plant senescence is estimated to involve 10 percent of genes in the genome. Plants use an expedited hypersensitive process to thwart pathogens by sacrificing infected cells to protect the surrounding healthy tissues.
The slower version of the cell-dying process is what lights up hillsides in autumn:
botanical recycling that ensures the nutrients and proteins in the leaves have been stowed for use in next spring's flowers seeds and leaves.
What we have found is the convergence point between the slow and fast death systems Gan says.
In the current study the increase in leaf longevity was significant but was tallied in days.
Gan expects further research to enable the delay of senescence for weeks. In the current transport and storage-based food system senescence after harvest whittles away at fruit and vegetable quality.
Gan envisions applications that will produce leafy greens that stay fresh floral bouquets that last longer and crops that keep their nutrients with an extended shelf life and less postharvest loss.
Manipulating this pathway also holds promise for bigger harvests and healthier plants. Much of the progress plant breeders have made in improving plant yields is actually due to delaying leaf senescence Gan says.
You need long-lived green tissue to support the production of fruits vegetables and seeds so senescence limits the yield of many crops.
His lab group is already working with other genes in the salicylic acid pathway including a master regulator gene with promising results.
When they switched the gene off using molecular tools soybean yields were increased by up to 44 percent t
#How slow-wave sleep helps us learn Boston University Brown University Posted by David Orenstein-Brown on August 22 2013brown (US)# Scientists have pinpointed the brainwave frequencies
and brain region associated with sleep-enhanced learning of a finger-tapping task akin to typing
or playing piano.##The mechanisms of memory consolidations regarding motor memory learning were still uncertain until now#says Masako Tamaki a postdoctoral researcher at Brown University
and lead author of the study appearing today in the Journal of Neuroscience.##We were trying to figure out which part of the brain is doing
#Slow-wave sleepspecifically the results of complex experiments performed at Massachusetts General Hospital and then analyzed at Brown show that the improved speed
Scientists have shown that sleep improves many kinds of learning including the kind of sequential finger-tapping motor tasks addressed in the study
It s an intensive activity for the brain to consolidate learning and so the brain may benefit from sleep perhaps
because more energy is available or because distractions and new inputs are fewer says corresponding author Yuka Sasaki a research associate professor in the department of cognitive linguistic & psychological sciences.#
#Sleep is not just a waste of time#Sasaki says. The extent of reorganization that the brain accomplishes during sleep is suggested by the distinct roles the two brainwave oscillations appear to play.
and their team asked each of their 15 subjects to volunteer for the motor learning experiments.
while their brains were scanned both with magnetoencephalography (MEG) which measures the oscillations with precise timing and polysomnography
On day five the researchers scanned each volunteer with an magnetic resonance imaging machine which maps brain anatomy
Visual learning next? In all the experimenters tracked five different oscillation frequencies in eight brain regions (four distinct regions on each of the brain s two sides.
which governs motor control but instead the significant changes occurred in the SMA on the opposite side of the trained hand.
since a project to further study how the brain consolidates learning. In this case they re looking at visual learning tasks.#
#Will we see similar effects?##Sasaki asks.##Would it be with similar frequency bands and a similar organization of neighboring brain areas?#
#In addition to Tamaki Sasaki and Watanabe other authors on the paper contributed from Boston University MGH National Taiwan University and Arizona State university.
Data analysis at Brown took place using the computing resources of the Center for Computation and Visualization.
#Surprise virus caused blue chicken eggs University of Nottingham rightoriginal Studyposted by Emma Rayner-Nottingham on August 20 2013u.
NOTTINGHAM (UK)# Scientists have identified the genetic mutation responsible for the first blue chicken eggs in South american Mapuche fowl and their European descendants Araucana 200 to 500 years ago.
The results published in PLOS ONE could inform future research into agricultural breeding techniques if demand grows for the blue eggs
or#fancy#poultry breeders to identify at fine resolution the exact location of the mutation in the genome in blue egg laying chickens.
This makes it possible for genetic material from a retrovirus to become permanently incorporated into the DNA of an infected cell.
In this case the retrovirus effect was to trigger an accumulation of a green-blue bile pigment called biliverdin in the eggshell as the egg develops in the hen.
Unlikely odds#An unexpected find was the unique integration sites for the retrovirus in South american/European
and Asian chickens#says team leader David Wragg a doctoral research fellow at University of Nottingham.#
and diversity of species. It s quite remarkable#retroviruses are considered generally to integrate at random locations in the genome
#Moreover when appearing in the population the unusual egg coloration must have attracted the attention of the owners who must be praised for having selected the trait in subsequent breeding.#
They are commonly found across species of birds including those that lay blue eggs as well as non-blue eggs within a single population like the cuckoo and guillemot.#
#Rare breedsprofessor Olivier Hanotte initiated the work after becoming curious about blue eggs on a trip to Brazil where he met Professor Jos##Antonio Alcalde a co-author of the paper.#
and indeed promoted by agriculture#says Hanotte. A research group in China independently discovered and reported the same findings with local Chinese and North american breeds.
Additional researchers contributed to the study from Universidad Catolica de Chile Institut National de la Recherche Agronomique in France International livestock research institute in Kenya Chinese Academy of Agricultural sciences in China
and the University of Sydney in Australia. Source: University of Nottinghamyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license t
#Genes from the father build the placenta CORNELL (US)- Placentas support the fetus and mother but new research with horses mules and donkeys confirms that the father provides the genetic blueprints for the organ.
Genes work in pairs: one from each parent. But about one percent of mammalian genes choose sides a phenomenon called genomic imprinting.
Imprinted genes use molecules that bind to DNA (epigenetic tags) to quiet one half and let the other lead.
This is the first study to offer an unbiased profile of novel imprinted genes in a mammal other than mice says lead author Xu Wang a postdoctoral associate in the laboratory of senior author Andrew Clark professor
of molecular biology and genetics at Cornell University. Using mouse studies only about 100 genes with imprinted expression had been identified.
To determine whether other genes exhibit imprinted expression Wang and colleagues sequenced all of the expressed genes (the transcriptome) of hinnies (who have donkey moms
Because the genomes of horses and donkeys differ by approximately one in every 200 base pairs (differences called single nucleotide polymorphisms
Of those genes transcriptome data from placental tissue revealed that 93 genes were imprinted. While only 15 of the 40 known imprinted human genes were identified in this set their expression bias was identical to that of humans indicating a highly conserved function for these genes between the horse family and humans.
Mouse experiments showed that if all DNA comes from the mother the embryo grows quite well
Breeding strategythe methods used in the study may also help breeders. This discovery explains what breeders call the maternal grandsire effect says co-senior author Doug Antczak equine geneticist at Cornell s College of Veterinary medicine.
Some genes like so-called speed genes in great racehorses skip a generation and only express in grandchildren if their carrier was a certain sex.
which could help breeders decision-making Better understanding of genomic imprinting may offer insights into several human diseases.
Mistakes in imprinting genes can impair development spurring genetic problems that can cause gigantism dwarfism neurological failures incomplete sexual development and others.
#Add arsenic to magnesium to make it stainless Monash University rightoriginal Studyposted by Emily Walker-Monash on August 19 2013monash U. AUS)# Adding a little arsenic to magnesium slows down the metal s corrosion
rate paving the way for a more lightweight material for cars and electronics. Weighing in at two thirds less than aluminum magnesium is the lightest structural metal.
But the usefulness of the metal is restricted severely by its poor resistance to corrosion. Research efforts to develop lighter metals have explored way to create a stainless or corrosion-resistant form of magnesium.
A team led by Nick Birbilis an associate professor of materials engineering at Monash University found that the addition of very low levels of arsenic to magnesium retards the corrosion reaction by effectively#poisoning#the reaction before it completes.
The discovery Birbilis notes would contribute to the birth of more stainless magnesium products by exploiting cathodic poisons.
The findings are reported in the journal Electrochemistry Communications.##In an era of light-weighting for energy and emissions reductions there is a great demand for magnesium alloys in everything from portable electronics to air
and land transportation#Birbilis says.##Magnesium products are rapidly evolving to meet the demands of industry
but presently are hindered by high corrosion rates. The arsenic effect we discovered is now being trialed as a functional additive to existing commercial alloys.#
#Our breakthrough will help develop the next generation of magnesium products which must be more stainless.#
#Bubble lens bends nano beam of light PENN STATE (US) Using a few tiny liquid bubbles to bend light beams could open the doors for next-generation, high-speed circuits and displays, according to new research.
researchers use nanoplasmonicsevices that use short electromagnetic waves to modulate light on the nanometer scale, where conventional optics do not work.
However, aiming and focusing this modulated light beam at desired targets is difficult. here are different solid-state devices to control (light beams),
associate professor of engineering science and mechanics at Penn State. sing a bubble has a lot of advantages. he main advantage of a bubble lens is just how quickly
Fine control over these light beams will enable improvements for on-chip biomedical devices and super resolution imaging. or all these applications,
you really need to precisely control light in nanoscale, and that where this work can be a very important component,
says Huang. Chenglong Zhao, postdoctoral fellow in engineering science and mechanics at Penn State designed and conducted the experiment;
Yongmin Liu, assistant professor of mechanical and industrial engineering, and electrical and computer engineering at Northeastern University, worked with Nicholas Fang, associate professor of mechanical engineering at MIT,
to analyze the results and develop simulations; and Yanhui Zhao, graduate student in engineering science and mechanics at Penn State, fabricated the materials.
The National institutes of health, the National Science Foundation, and the Penn State Center for Nanoscale Science funded this study.
Source: Penn Stat i
#Silicon system produces squeezed light California Institute of technology rightoriginal Studyposted by Kimm Fesenmaier-Caltech on August 9 2013caltech (US)# A new system constructed on a silicon microchip offers a more useful way to produce the ultraquiet
light known as squeezed light. One of the many counterintuitive and bizarre insights of quantum mechanics is that even in a vacuum
Although other research groups previously have produced squeezed light the new system generates the ultraquiet light in a way that can be adapted more easily to a variety of sensor applications.#
#This system should enable a new set of precision microsensors capable of beating standard limits set by quantum mechanics#says Oskar Painter a professor of applied physics at Caltech
#Our experiment brings together in a tiny microchip package many aspects of work that has been done in quantum optics and precision measurement over the last 40 years.#
This latest work marks the first time that squeezed light has been produced using silicon a standard material.#
#We work with a material that s very plain in terms of its optical properties#says Amir Safavi-Naeini a graduate student in Painter s group
and integration enabling a great many applications in electronics.##Cancel each other outin this new system a waveguide feeds laser light into a cavity created by two tiny silicon beams.
Once there the light bounces back and forth a bit thanks to the engineered holes which effectively turn the beams into mirrors.
And as is the case with the noise-canceling technology used for example in some headphones the fluctuations that shake the beams interfere with the fluctuations of the light.
#The National Science Foundation the Gordon and Betty Moore Foundation the Air force Office of Scientific research and the Kavli Nanoscience Institute at Caltech supported the work.
#Ice may explain odd craters on Mars Brown University right Original Studyposted by Kevin Stacey-Brown on August 6 2013brown (US) More than 600 double-layer craters on Mars may have been caused by debris
These distinctive craters were documented first in data returned from the Viking missions to Mars in the 1970s
Recent discoveries by planetary geoscientists at Brown and elsewhere have shown that the climate of Mars has varied in the past says James W. Head professor of geological science at Brown University.
In the scenario Head and graduate student David Kutai Weiss describe in the journal Geophysical Research Letters the impact blasts through the ice layer spitting rock and other ejecta out onto the surrounding ice.
That landslide enabled by steep slopes and a slick ice layer creates the DLES telltale two-layered appearance.
since DLES were discovered in the 1970s we have a model for their formation that appears to be consistent with a very wide range of known data Weiss says.
A key ingredient The landslide scenario explains several of the distinct features of DLES the researchers say.
Striations are common in landslides On earth Weiss says especially landslides on glaciers. That got Weiss
Ice would reduce the coefficient of friction on the slopes of crater rims increasing the likelihood of a slide.
I realized that the landslide wouldn be expected to happen (on crater rims) unless the ejecta was landsliding on an ice layer Weiss says.
Craters larger than about 25 kilometers probably wouldn have steep enough rims to cause an icy landslide.
NASA supported the work. Source: Brown University you are free to share this article under the Creative Commons Attribution-No Derivs 3. 0 Unported license c
#Gene protects beer crop from nasty fungus Original Studyposted by Ron Hohenhaus-Queensland on August 5 2013 Finding the gene that gives barley resistance to leaf rust could benefit people who rely on the crop
for food and beer. Researchers have discovered that the gene Rph20 provides resistance to leaf rust in some barley variety adult plants.
Leaf rust is a fungal disease that could destroy almost a third of the nation s barley crop,
says Lee Hickey a research fellow at University of Queensland. The discovery will enable selective breeding of barley that will provide genetic protection to the disease.
This will result in much lower chemical use reduced crop losses and a more reliable grain supply.
Hickey says the crop disease could also leave Australian beer drinkers thirsty because the country's primary use of barley was to make beer as well as stock feed.
But for areas like North africa and Southwest asia it is a food staple, he says. Using field trials in Australia
Their findings appear in Theoretical and Applied Genetics. It was a surprise that we could trace the gene back so far
He says his research also shows that the Rph20 gene had resistance to powdery mildew another devastating barley disease.
It seems to be a key gene in the barley genome, he says. Hickey has declined to patent the DNA marker preferring the information to be freely available to other researchers.
Hickey teamed up with scientists from the Queensland Department of agriculture Fisheries and Forestry; the University of Sydne;
and Uruguay's Instituto de Investigacion Agropecaria. The Grains Research and development Corporation partially funded the study.
University of Queenslan n
#Compact graphene device could shrink supercapacitors Monash University rightoriginal Studyposted by Emily Walker-Monash on August 5 2013monash U. AUS)# A new strategy to engineer graphene-based supercapacitors could make them viable
for widespread use in renewable energy storage portable electronics and electric vehicles. Supercapacitors are made generally of highly porous carbon impregnated with a liquid electrolyte to transport the electrical charge.
Known for their almost indefinite lifespan and the ability to recharge in seconds the drawback of existing supercapacitors is their low energy-storage-to-volume ratio#known as energy density.
Low energy density of five to eight watt-hours per liter means supercapacitors are unfeasibly large or must be recharged frequently.
Dan Li a materials engineering professor at Monash University and his team created a supercapacitor with energy density of 60 watt-hours per liter#comparable to lead-acid batteries and around 12 times higher than commercially available supercapacitors.#
#It has long been a challenge to make supercapacitors smaller lighter and compact to meet the increasingly demanding needs of many commercial uses#says Li.
Graphene which is formed when graphite is broken down into layers one atom thick is very strong chemically stable and an excellent conductor of electricity.
To make their uniquely compact electrode Li s team exploited an adaptive graphene gel film they had developed previously.
They used liquid electrolytes#generally the conductor in traditional supercapacitors#to control the spacing between graphene sheets on the subnanometer scale.
In this way the liquid electrolyte played a dual role: maintaining the minute space between the graphene sheets and conducting electricity.
Unlike in traditional#hard#porous carbon where space is wasted with unnecessarily large pores density is maximized without compromising porosity in Li s electrode.
To create their material the research team used a method similar to that used in traditional paper making meaning the process could be easily
and cost-effectively scaled up for industrial use.##We have created a macroscopic graphene material that is a step beyond
what has been achieved previously. It is almost at the stage of moving from the lab to commercial development#Li says.
The Australian Research Council supported the work which was reported in the journal Science. Source: Monash Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license v
#Robots show how alcohol calms fear in fish New york University rightoriginal Studyposted by James Devitt-NYU on July 31 2013nyu (US)# Bio-inspired robots that look like predators can scare fish
but a high dose of ethanol can blunt their fear according to new research. These findings may pave the way for new methodologies for understanding anxiety
and other emotions as well as substances that alter them. Maurizio Porfiri associate professor of mechanical and aerospace engineering at the Polytechnic institute of New york University (NYU-Poly) and Simone Macr##a collaborator at the Istituto Superiore di Sanit##in Rome Italy published their findings
in PLOS ONE. Porfiri and his colleagues believe zebrafish may be a suitable replacement for higher-order animals in tests to evaluate emotional responses.
Scary robotporfiri and Macri along with students Valentina Cianca and Tiziana Bartolini hypothesized that robots could be used to induce fear as well as affinity
In the lab they simulated a harmless predatory scenario placing the zebrafish and the robotic Indian leaf fish in separate compartments of a three-section tank.
Ethanol has been shown to influence anxiety-related responses in humans rodents and some species of fish.
and his collaborators conducted two traditional anxiety tests and evaluated whether the results obtained therein were sensitive to ethanol administration.
They placed test subjects in a two-chamber tank with one well-lit side and one darkened side to establish which conditions were preferable.
In a separate tank they simulated a heron attack from the water s surface#herons also prey on zebrafish
As expected the fish strongly avoided the dark compartment and most sought shelter very quickly from the heron attack.
and significantly slowing the fishes retreat to shelter during the simulated attack.##We hoped to see a correlation between the robotic Indian leaf fish test results
and the results of the other anxiety tests and the data support that#Porfiri explains.#
#The majority of control group fish avoided the robotic predator preferred the light compartment and sought shelter quickly after the heron attack.
Among ethanol-exposed fish there were many more who were unaffected by the robotic predator preferred the dark compartment
#The National Science Foundation the Honors Center of Italian Universities and the Mitsui USA Foundation supported the research.
#To beat stem rust, wheat crops get new gene University of California Davis rightoriginal Studyposted by Pat Bailey-UC Davis on July 30 2013uc DAVIS (US)# Scientists
have found a gene in wild wheat that could make commercial wheat varieties resistant to a new strain of stem rust.
The stem rust disease is producing large wheat yield losses throughout Africa and Asia and threatening global food security.
By transferring this gene to commercial wheat varieties wheat breeders will have a distinct advantage in controlling the epidemic the researchers say.
#A new race of a wheat disease called stem rust Ug99 has been spreading over large distances
since 1999 threatening important wheat production areas of the world#says co-author Jorge Dubcovsky a wheat geneticist at University of California Davis and a Howard hughes medical institute investigator.#
#This study identifies a gene called Sr35 that confers near-immunity to this new race#he says.
and the year the new race was discovered appears on wheat as small red growths dotted across the stems and leaves.
About 90 percent of the wheat varieties grown worldwide are susceptible to Ug99. Previous resistance genes that had proven effective for fighting the disease for 50 years are ineffective against this new race.
Scientists are now looking for new sources of resistance to protect the global wheat crop which millions of people depend on for food.
The researchers selected the resistance gene Sr35 for its immunity to Ug99 and related races.
Sr35 was known to be present in the wheat species Triticum monococcum a close relative of pasta and bread wheat.
The team sequenced a region of 300000 base pairs#the building blocks of DNA#in T. monococcum and identified four candidate genes.
and transgenic plants they identified the gene responsible for the resistance. They then inserted the gene into a wheat variety that is susceptible to the diseases engineering a resistance to Ug99.#
#This discovery opens the door for biotechnological approaches to fight this devastating disease#says Eduard Akhunov an associate professor at Kansas State university and co-director of the project.
The challenge now is to identify which combination of resistance genes can deliver a more durable resistance against the disease.
The study is part of the Borlaug Global Rust Initiative a five-year effort funded by the Bill and Melinda Gates Foundation to coordinate international efforts in fighting Ug99.
It is supported by the US Department of agriculture#s National Institute of Food and Agriculture. Additional researchers from UC Davis Department of Plant sciences the USDA-ARS Cereal Disease Laboratory and Kansas State university also contributed to the study.
Source: UC Davisyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license
#Convert microscope into billion-pixel imager for $200 CALTECH (US) Engineers have devised a way to convert a conventional microscope into a billion-pixel imaging system for about $200. n my view,
what wee come up with is very exciting because it changes the way we tackle high-performance microscopy,
says Changhuei Yang, professor of electrical engineering, bioengineering and medical engineering at the California Institute of technology (Caltech).
And building upon a conventional microscope, the new system costs only about $200 to implement. ne big advantage of this new approach is the hardware compatibility,
No other hardware modification is needed. The rest of the job is done by the computer. The new system acquires about 150 low-resolution images of a sample.
Each image corresponds to one LED element in the LED array. Therefore in the various images, light coming from known different directions illuminates the sample.
A novel computational approach, termed Fourier ptychographic microscopy (FPM), is used then to stitch together these low-resolution images to form the high-resolution intensity
Pathology, forensics, and beyond Yang explains that when we look at light from an object, we are only able to sense variations in intensity.
The very large field of view that the new system can image could be particularly useful for digital pathology applications,
because the system acquires a complete set of data about the light field, it can computationally correct errorsuch as out of focus-focus imageso samples do need not to be rescanned. t will take the same data
and allow you to perform refocusing computationally, Yang says. The researchers say that the new method could have wide applications not only in digital pathology but also in everything from hematology to wafer inspection to forensic photography.
Zheng says the strategy could also be extended to other imaging methodologies, such as X-ray imaging and electron microscopy.
The National institutes of health supported the work
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