Mammoths, sabre-tooth tigers and other megafauna went extinct because of ancient climate change


‘We should be quite worried about the warming that is going on now and … about whether again we are going to see a suite of extinctions’

Mammoths, sabre-tooth tigers, giant sloths and other ‘megafauna’ died out across most of the world at the end of the last Ice Age because the changing climate became too wet, according to a new study.

By studying the bones of the long-dead animals, researchers were able to work out levels of water in the environment.

And they found a link between the time large grassland animals and their predators became extinct in different parts of the world over a period of 15,000 to 11,000 years ago and a sudden increase in moisture.

This changed the environment from one dominated by grass to one more suited to trees, bogs and peatlands at the same time as human hunters moved in – creating a lethal “double whammy” that proved too much for many species.

The researchers warned that this process showed how vulnerable today’s large grassland animals could be to climate change, which will result in an increase in rainfall in some places.

One of the researchers, Professor Alan Cooper, of the Australian Centre for Ancient DNA at Adelaide University, said in a video: “What we have found by looking into the actual bones themselves is a signal of sudden environmental change just before they became extinct.

“We see water, moisture, everywhere, which we think is changing the vegetation patterns away from grass, which is what they want, towards trees. What we are really seeing is a double whammy, where the environment is suddenly shifting, the populations are in major trouble, and humans are turning up and hunting is taking off.”

It had long been a “big mystery” why Africa’s megafauna had remained when populations in the rest of the world died out, he said.

“The idea has been that they evolved with humans and were somehow used to them,” said Professor Cooper.

“What we see instead is, because there were no glaciers and large amounts of water to melt, grasslands were always present in Africa, so the animals never had the stress they had elsewhere.

“So it had nothing to do with being use to humans.”

He said the timing of the extinctions around the world, which hit South America first, then North America and then Europe, correlated with the increase in water.

“What it shows is climate change can have some quite large impacts across landscape-sized environments and that we should be quite worried about the warming that is going on now, the changes in water production, and about whether again we are going to see a suite of extinctions,” he said.

Elephants, rhinos and giraffes could all be at risk. “With added rainfall in these areas, we could actually see some quite major impacts on these populations, relatively quickly,” Professor Cooper said.

The international team of researchers, from the US, Russia and Canada as well as Australia, looked at levels of nitrogen isotopes from bone collagen that had been radiocarbon dated. This gave an indication of levels of moisture in the landscape, they said in a paper about the research in the journal Nature Ecology and Evolution.

“Grassland megafauna were critical to the food chains. They acted like giant pumps that shifted nutrients around the landscape,” said Dr Tim Rabanus-Wallace, also of Adelaide University.

“When the moisture influx pushed forests and tundras to replace the grasslands, the ecosystem collapsed and took many of the megafauna with it.”

Plants can ‘hear’ themselves being eaten, say researchers


Researchers have found that plants can identify sounds nearby, such as the sound of eating. 

Most people don’t give a second thought when tucking into a plate of salad.

But perhaps we should be a bit more considerate when chomping on lettuce, as scientists have found that plants actually respond defensively to the sounds of themselves being eaten.

The researchers at the University of Missouri (MU) found that plants can identify sounds nearby, such as the sound of eating, and then react to the threats in their environment, reports Daily Mail.

“Previous research has investigated how plants respond to acoustic energy, including music,” said Heidi Appel, senior research scientist in the Division of Plant Sciences in the College of Agriculture, Food and Natural Resources and the Bond Life Sciences Center at MU.

“However, our work is the first example of how plants respond to an ecologically relevant vibration.

“We found that ‘feeding vibrations’ signal changes in the plant cells’ metabolism, creating more defensive chemicals that can repel attacks from caterpillars.”

Appel collaborated with Rex Cocroft, professor in the Division of Biological Sciences at MU.

In the study, caterpillars were placed on Arabidopsis, a small flowering plant related to cabbage and mustard.

Using a laser and a tiny piece of reflective material on the leaf of the plant, Cocroft was able to measure the movement of the leaf in response to the chewing caterpillar.

Cocroft and Appel then played back recordings of caterpillar feeding vibrations to one set of plants, but played back only silence to the other set of plants.

When caterpillars later fed on both sets of plants, the researchers found that the plants previously exposed to feeding vibrations produced more mustard oils, a chemical that is unappealing to many caterpillars.

“What is remarkable is that the plants exposed to different vibrations, including those made by a gentle wind or different insect sounds that share some acoustic features with caterpillar feeding vibrations did not increase their chemical defenses,” Cocroft said.

“This indicates that the plants are able to distinguish feeding vibrations from other common sources of environmental vibration.”

Appel and Cocroft say future research will focus on how vibrations are sensed by the plants, what features of the complex vibrational signal are important, and how the mechanical vibrations interact with other forms of plant information to generate protective responses to pests.

“Plants have many ways to detect insect attack, but feeding vibrations are likely the fastest way for distant parts of the plant to perceive the attack and begin to increase their defenses,” Cocroft said.

“Caterpillars react to this chemical defense by crawling away, so using vibrations to enhance plant defenses could be useful to agriculture,” Appel said.

“This research also opens the window of plant behavior a little wider, showing that plants have many of the same responses to outside influences that animals do, even though the responses look different.”

The study, “Plants respond to leaf vibrations caused by insect herbivore chewing,” was funded in part by the National Science Foundation and was published in Oecologia.

Plants can ‘talk’ too…

Researchers in Bonn, Germany, found plants give off a gas when under “attack”.

Super-sensitive microphones picked up a “bubbling” sound from a healthy plant.

But this rose to a piercing screech when it was under threat.

Even a tiny insect bite could have an effect.

“The more a plant is subjected to stress, the louder the signal,” said Dr Frank Kühnemann.

Plants do not actually scream in pain. But different sounds are heard when the gas they emit, ethylene, is bombarded with lasers.

The research could help to work out which pieces of fruit and vegetables are likely to stay fresh longer, as a cucumber which is starting to go off produces a squealing sound.

It could then be separated from the fresher ones.

Source:nzherald.co.nz

Brain Cells We Thought Were Just Fillers Might Actually Be the Key to Our Body Clocks


Neurons aren’t everything.

Scientists have discovered that brain cells that were once considered to be simple place-holders for neurons could actually play an important role in helping to regulate our circadian behaviour.

Astrocytes are a kind of glial cell – the support cells that are often called the glue of the nervous system, as they provide structure and protection for neurons. But a new study shows that astrocytes aren’t just gap-fillers, and may be crucial for keeping time in our inner body clock.

 Scientific consensus has long regarded our internal clock as being controlled by the suprachiasmatic nuclei (SCN), a brain region in the hypothalamus made up of around 20,000 neurons. But there’s about 6,000 star-shaped astrocyte cells in the same area, the exact function of which has never been fully explained.

Now, a team from Washington University in St. Louis has figured out how to independently control astrocytes in mice – and by altering the astrocytes, the scientists were able to slow down the animals’ sense of time.

“We had no idea they would be that influential,” says one of the researchers, Matt Tso.

It was once thought the suprachiasmatic nuclei was the only part of the brain that regulated circadian rhythms, but scientists now understand that cells throughout the body all have their own circadian clocks – including the cells that make up our lungs, heart, liver, and everything else.

In 2005, one of the team, neuroscientist Erik Herzog, helped figure out that astrocytes also include these clock genes.

By isolating the brain cells from rats and coupling them with a bioluminescent protein, Herzog’s team showed that they glowed rhythmically – evidence that they were capable of keeping time like other cells.

 It took more than a decade for the researchers to figure out how to measure the same astrocyte behaviour in a living specimen, by using CRISPR-Cas9 gene-editing to delete a clock gene called Bmal1 in the astrocytes of mice.

Left to their own devices, mice have circadian clocks that last for approximately 23.7 hours. We know this because mice in constant darkness will start running on a wheel every 23.7 hours, and usually don’t miss their time slot by more than 10 minutes.

Humans also miss the 24-hour mark slightly – a Harvard University study in 1999 found that our internal clocks run a tad overlong, on a daily cycle of 24 hours, 11 minutes.

But even though Herzog had demonstrated in 2005 that astrocytes were involved in keeping time, the team didn’t necessarily expect mice without Bmal1 to be affected, because most research surrounding the suprachiasmatic nuclei has demonstrated the controlling effect of neurons, not astrocytes.

“When we deleted the gene in the astrocytes, we had good reason to predict the rhythm would remain unchanged,” says Tso.

“When people deleted this clock gene in neurons, the animals completely lost rhythm, which suggests that the neurons are necessary to sustain a daily rhythm.”

But, to the researchers’ surprise, deleting the clock gene in the astrocytes saw the mouse internal clocks run slower – beginning their daily run about 1 hour later than usual.

In another experiment, the team studied mice with a mutation that caused their circadian clocks to run fast. By repairing this gene in the animals’ astrocytes – but not fixing the defect in their neurons – they weren’t sure what the affect would be.

“We expected the SCN to follow the neurons’ pace,” says Tso. “There are 10 times more neurons in the SCN than astrocytes. Why would the behaviour follow the astrocytes?”

With the mutation fixed in the animals’ astrocytes, the mouse began their running routine 2 hours later than mice that hadn’t had the mutation repaired (in either astrocytes or neurons).

“[These results] suggests that the astrocytes are somehow talking to the neurons to dictate rhythms in the brain, and in behaviour,” Herzog told Diana Kwon at The Scientist.

While the researchers acknowledge that they don’t fully understand the extent to which astrocytes control circadian behaviour, it’s clear something powerful is going on.

Of course, we can’t guarantee yet whether astrocytes in humans are regulating body clocks in the same way, but that’s something that later studies may be able to confirm.

We’ll have to wait to see the results of future research to know more, but until then, one thing’s for sure – these brain cells are definitely there for a lot more than just neuron padding.

Source:http://www.sciencealert.com

The World’s Rarest and Most Ancient Dog Has Just Been Re-Discovered in the Wild


The first sighting in more than half a century.

After decades of fearing that the New Guinea highland wild dog had gone extinct in its native habitat, researchers have finally confirmed the existence of a healthy, viable population, hidden in one of the most remote and inhospitable regions on Earth.

According to DNA analysis, these are the most ancient and primitive canids in existence, and a recent expedition to New Guinea’s remote central mountain spine has resulted in more than 100 photographs of at least 15 wild individuals, including males, females, and pups, thriving in isolation and far from human contact.

 “The discovery and confirmation of the highland wild dog for the first time in over half a century is not only exciting, but an incredible opportunity for science,” says the group behind the discovery, the New Guinea Highland Wild Dog Foundation (NGHWDF).

“The 2016 Expedition was able to locate, observe, gather documentation and biological samples, and confirm through DNA testing that at least some specimens still exist and thrive in the highlands of New Guinea.”

If you’re not familiar with these handsome creatures, until now, New Guinea highland wild dogs were only known from two promising but unconfirmed photographs in recent years – one taken in 2005, and the other in 2012.

They had not been documented with certainty in their native range in over half a century, and experts feared that what was left of the ancient dogs had dwindled to extinction.

But maybe they were just really good at hiding?

Last year, a NGHWDF expedition made it to the Papua province of western New Guinea, which is bordered by Papua New Guinea to the east and the West Papua province to the west.

 Led by zoologist James K McIntyre, the expedition ran into local researchers from the University of Papua, who were also on the trail of the elusive dogs.

A muddy paw print in September 2016 finally gave them what they were looking for – recent signs that something distinctly dog-like was wandering the dense forests of the New Guinea highlands, some 3,460 to 4,400 metres (11,351 to 14,435 feet) above sea level.

Trail cameras were immediately deployed throughout the area, so they could monitor bait sites around the clock. The cameras captured more than 140 images of wild Highland Wild Dog in just two days on Puncak Jaya – the highest summit of Mount Carstensz, and the tallest island peak in the world.

dogPregnant female.

new-guinea-pupsHighland wild dog pups.

The team was also able to observe and document dogs in the area first-hand, and DNA analysis of faecal samples have confirmed their relationship to Australian dingos and New Guinea singing dogs – the captive-bred variants of the New Guinea highland wild dog.

Due to the lack of evidence of the species, it’s been unclear exactly how dingoes, singing dogs, and highland wild dogs actually relate to one another, but that’s a question that will hopefully soon be answered, because these animals truly are our best bet for getting a better understanding of canid evolution.

As the NGHWD explains:

“The fossil record indicates the species established itself on the island at least 6,000 years ago, believed to have arrived with human migrants. However, new evidence suggests they may have migrated independently of humans.

While the taxonomy and phylogenetic relationships with related breeds and Australian dingoes is currently controversial and under review for both New Guinea singing dogs and highland wild dogs, the scientific and historical importance of the highland wild dog remains critical to understanding canid evolution, canid and human co-evolution and migrations, and human ecology and settlement derived from the study of canids and canid evolution.”

As far as dogs go, you’d be hard-pressed to find a more attractive one – their coats are most commonly golden, but there are also black and tan, and cream variants. Their tails are carried high over their backsides in a fish hook shape, like a Shiba Inu.

In all of the dogs observed so far, their ears sit erect and triangular on the top of the head.

dog-variantsSome of the wild dog sightings. 

running-dogA wary observer. 

Though it’s yet to be confirmed, the highland wild dogs could make the same unique vocalisations of their captive-bred counterparts – the New Guinea singing dogs.

According to the NGHWDF, there are roughly 300 New Guinea singing dogs remaining in the world, living in zoos, private facilities, and private homes, and they’re known for their high-pitched howls, which they will perform in chorus with one another, and sometimes for several minutes at a time:

 The research into these amazing dogs is ongoing, and a scientific paper on the discovery is expected to be released in the coming months.

And the good news is the researchers are optimistic of the highland wild dogs’ chances of survival.

Local mining companies have been tasked with taking special environmental stewardship measures to protect the remote area and ecosystem surrounding their facilities, which means they have “inadvertently created a sanctuary in which the HWD could thrive”, says the NGHWDF.

Soure:sciencealert.com

The Amount of Food Spiders Eat Each Year Will Haunt You for the Rest of Your Life


Spiders are already horrifying, with their eight beady little eyes and spindly legs and sticky webs. They also probably eat more meat than your mind can wrap your head around—more meat than humans eat, even.
 Spider meal specialist Martin Nyffeler of the University of Basel, Switzerland decided, hey, let’s try and estimate the total weight of all of the food spiders around the world eat per year. Some data crunching resulted in a number so bafflingly high you’ll either squirm or thank the spiders for keeping us safe from all the other bugs. Maybe both.

That number: The world’s estimated 25 million metric tons of spiders eat between 300 and 800 million metric tons of food per year, according to estimates published today in the very silly-sounding journal The Science of Nature. (That almost feels like calling something the Ferrari of Lamborghinis in academic journal speak). That food consists mainly of insects, little non-insect bugs called springtails, and even small vertebrates. The researchers make several assessments, using the amount of food individual spiders need to eat, the number of insects they catch in their webs, and the number of insects they kill on the hunt.

The 300 to 800 million metric ton figure is pretty close to the mass of meat and fish humans eat per year—around 400 metric tons, according to the paper. It’s also equal to the mass of humans: There are 7.4 billion people on earth, and the average human’s weight is around 130 pounds. Converted to metric tons, that’s a bit over 400 million.

 The idea to do this eye-opening calculation came from a book Nyffeler read 40 years ago, The World of Spiders by arachnologist William Bristowe in 1958, according to a prepared statement he passed along to Gizmodo. “In this book, Bristowe speculated that the weight of insects annually killed by the British spider population would exceed the combined weight of the British human population,” wrote Nyffeler. “This statement fascinated me very much. I decided that I would like to find out if Bristowe was correct with his speculation.”

You might think this means spiders are helping our crops by eating all of the pests, but that doesn’t seem to be the case. “Instead spiders appear to play a significant ecological role as predators of insects in forests and undisturbed grasslands,” Nyffeler wrote. Very generally speaking, spiders don’t seem to eat as many bugs in agricultural areas because these heavily managed systems don’t have as many or as good an assortment of prey.

Our apologies for that horrible image. But hey, at least they aren’t eating you. Yet.

Source:The Science of Nature

A new hypothesis of dinosaur relationships and early dinosaur evolution.


http://www.nature.com/articles/nature21700.epdf?shared_access_token=wWbPp9i0ayNUOMDM3guieNRgN0jAjWel9jnR3ZoTv0M90DUzIj8q5jPeCtoSdpixH6OYZOIXl8EqiIH6Dw4foZQUO3VABRKeiusHHJIqMuhLCkQcU95Md7NH4gnaOiyGG6YN5kR7Po9DYGrMTaTXbQyfz_cmsLwRU3J_n0DHbmc%3D

Source:http://www.nature.com

Major United States University Proposes First-Ever “Bee Vaccines” In Order to Save Declining Population.


The plight of the bees has gotten more attention in the past few years, as people are finally getting the memo that saving our pollinator species is of the utmost importance.

Already, the monarch butterfly has been “decimated” by agricultural chemicals according to scientist and TV host Bill Nye, in large part because of the widespread over use of synthetic pesticides and neonicotinoid seed coatings.

Now, one major U.S. university is proposing a radical solution for saving the bees and restoring their health: the first-ever bee vaccinations.

Vaccinate the Bees to Protect Them From Disease?

According to a sponsored report by Arizona State University that recently ran on USAToday.com, the first-ever bee vaccinations are being researched by Gro Amdam, an ASU School of Life Sciences professor, with help of researchers from Finland and Norway.

The report notes that 87 of the top 115 food crops require pollination, and includes numbers of the staggering “worker” honeybee decline. Since 1940, the numbers have dropped from 6 million to 2.5 million hives today.

 bee vaccines created asu

If successfully developed, the vaccines would utilize a “key carrier of environmental bacteria” that is digested by queen bees when they eat royal jelly, called Vitellogenin. The substance is referred to in the report as a way of “naturally vaccinating” the next generation of bees by acting as a shuttle for bacterial pieces.

“As humans, we protect ourselves against devastating bacterial infections via vaccination … These vaccines … provide long-term protection because our bodies develop a physiological memory of the bacterial material in the vaccines. In contrast, everybody thought insects could not be vaccinated because insects do not have physiology that allows the immune system to have memories,” Amdam said.

The team is also experimenting with oral vaccines that contain the substance.

 “We develop vaccines with bacterial pieces that are given to queens and study the physiology that allows the vaccines to be effective,” she said. A grant has been received to continue the research until 2021, and the team is also looking into the benefits of potentially launching a large-scale bee vaccine program.

While the possibility of vaccinating bees may seem like an outlandish one to many in light of the common sense initiatives (including banning neonicotinoids or GMOs and limiting pesticide use like Europe has done), it is worth noting that the report also mentions herbicides, fungicides, and other toxic chemicals as part of the reason for the bee decline and colony collapse disorder.

The hope among many in the pro-organic and non-GMO movement is that by limiting these and other toxic agricultural practices, and switching to organic and other more holistic and natural methods of farming, the bee population can rebound without the use of labor intensive, expensive, and unproven pie-in-the-sky potential “solutions” like bee vaccination.

 

Scientists turn spinach leaf into working heart tissue


Worcester Polytechnic Institute Grows Heart Tissue on Spinach Leaves
Spinach is good for your heart 

Researchers have managed to turn a spinach leaf into working heart tissue and are on the way to solving the problem of recreating the tiny, branching networks of blood vessels in human tissue.

Until now, scientists have unsuccessfully tried to use 3D printing to recreate these intricate networks.

Now, with this breakthrough, it seems turning plants with their delicate veins into human tissue could be the key to delivering blood via a vascular system into the new tissue.

 Scientists have managed in the past to create small-scale artificial samples of human tissue, but they have struggled to create it on a large scale, which is what would be needed to treat injury.

Researchers have suggested that eventually this technique could be used to grow layers of healthy heart muscle to treat patients who have suffered a heart attack.

Watch the video. URL:

Plants and animals of course have very different ways of transporting chemicals around the body.

However, the networks by which they do so are quite similar.

The authors of the study are publishing their findings in research journal Biomaterials in May

The scientists, from the Worcester Polytechnic Institute wrote: “The development of decellularized plants for scaffolding opens up the potential for a new branch of science that investigates the mimicry between plant and animal.”

In order to create the artificial heart, the scientists stripped the plant cells from the spinach leaves, sending fluids and microbeads similar to human blood cells through the spinach vessels and then “seeded” the human cells which are used to line blood vessels into it.

 Glenn Gaudette, professor of biomedical engineering at Worcester Polytechnic Institute, said:  “We have a lot more work to do, but so far this is very promising.

“Adapting abundant plants that farmers have been cultivating for thousands of years for use in tissue engineering could solve a host of problems limiting the field.”

Source:http://www.telegraph.co.uk/

This mesmerising time-lapse of cell division is real, and it’s spectacular.


This is life.

 If you’ve ever wondered what cell division actually looks like, this incredible time-lapse by francischeefilms on YouTube gives you the best view we’ve ever seen, showing a real-life tadpole egg dividing from four cells into several million in the space of just 20 seconds.
 Of course, that’s lightening speed compared to how long it actually takes – according to Adam Clark Estes at Gizmodo, the time-lapse has sped up 33 hours of painstaking division into mere seconds for our viewing pleasure.

The species you see developing here is Rana temporaria, the common frog, which lays 1,000 to 2,000 eggs at a time in shallow, fresh water ponds.

According to the team behind the footage, they had to build their own equipment to film it like this, and had to devise a way to get the lighting and microscope set-up just right.

“The whole microscope sits on anti-vibration table. [I]t doesn’t matter too much what microscope people use to perform this,” francischeefilms describe on their YouTube page.

“There are countless other variables involved in performing this tricky shot, such as: the ambient temperature during shooting; the time at which the eggs were collected; the handling skills of the operator; the type of water used; lenses; quality of camera etc.”

Check out the footage. URL:https://youtu.be/Wz4igVjNGq4

Source:http://www.sciencealert.com

Scientists Have Figured out How Life Is Able to Survive


IN BRIEF
  • A new sequencing technique that maps out and analyzes DNA damage demonstrates how bacterial cells function in two critical excision repair proteins.
  • The team’s research and discovery not only heralds the use of this new mapping technique, it could also pave the way for a solution that will help address antibiotic resistance.

DNA-REPAIR SYSTEMS

Every day, the DNA in our cells gets damaged. This might sound scary, but it’s actually a normal occurrence – which makes DNA’s ability to repair itself vital to our survival. Now, scientists are beginning to better understand exactly how these repairs happen. A new sequencing technique that maps out and analyzes DNA damage demonstrates how bacterial cells function in two critical excision repair proteins: Mfd and UvrD.

The process, called nucleotide excision repair, has been used by a team from the UNC School of Medicine to gain a deeper insight into the key molecular functions of these repair systems, including the proteins’ roles in living cells. This repair process is known for fixing a common form of DNA damage called the “bulky adduct,” where a toxin or ultraviolet (UV) radiation chemically modifies the DNA.

The technique, called XR-seq lets the scientists isolate and sequence sections of DNA with the bulky adduct, thus allowing them to identify its actual locations in the genome. It has previously been used to generate a UV repair map of the human genome, as well as a map for the anticancer cisplatin drug.

For this study, scientists used the same method to repair damage caused by E. coli. As co-author of the study, Christopher P. Selby, PhD explained:

When the DNA of a bacterial gene is being transcribed into RNA, and the molecular machinery of transcription gets stuck at a bulky adduct, Mfd appears on the scene, recruits other repair proteins that snip away the damaged section of DNA, and “un-sticks” the transcription machinery so that it can resume its work. This Mfd-guided process is called transcription-coupled repair, and it accounts for a much higher rate of excision repair on strands of DNA that are being actively transcribed.

A POTENTIAL SOLUTION

f32e6aa3-7f8a-435f-b883-1a798e9616e3
Chris Selby, PhD; Aziz Sancar, MD, PhD; and Ogun Adebali, PhD

In further experiments, the researchers defined the role of an accessory excision repair protein in E. coli – UvrD, which helps clear away each excised segment of damaged DNA. Essentially, think of Mfd as the DNA “un-sticker” and UvrD as the “unwinder.” Using the XR-seq method, scientists discovered evidence of transcription-coupled repair in normal cells, but not in cells without Mfd—implying that the protein played a key role in its repair process.

The team’s research and discovery not only heralds the use of this new mapping technique, it could also pave the way for a solution that will help address the pressing, global threat of antibiotic resistance.

“If we fail to address this problem quickly and comprehensively, antimicrobial resistance will make providing high quality universal health coverage more difficult, if not impossible,” the UN Secretary-General Ban Ki-moon said. “[Antibiotic resistance] a fundamental, long-term threat to human health, sustainable food production and development.”

To support their current research, the team now plans to study XR-seq in bacterial, human and mammalian cells, to better understand the excision repair process.

Source:futurism.com