Scientists discover new form of DNA in human cells
DNA is typically thought of as having the familiar double-helix shape, and almost all living shapes on Earth have DNA in their cells.
But in an exciting new discovery, researchers have identified an elusive new structure of DNA called the “i-motif” for the first time in living cells.
The study was conducted by researchers from the Garvan Institute of Medical Research and published in the journal Nature Chemistry.
The double-helix chemical structure of DNA was first discovered in 1953 by scientists James Watson and Francis Crick.
Now, the double helix is not the only form of DNA as the i-motif has more of a twisted knot shape. The knot shape has been observed in other studies, but never before in living cells.
“When most of us think of DNA, we think of the double helix,” Daniel Christ, a leader of the research said in a statement. “This new research reminds us that totally different DNA structures exist – and could well be important for our cells.”
While the researchers are still not sure what the i-motif’s purpose is, the finding may help with interpreting DNA sequences.
To confirm the presence of i-motifs in living cells, the researchers created tiny probes made of antibodies that were engineered to bind to the knotted shapes. The researchers dyed the probes with a fluorescent color in order to locate the antibodies within the cell.
I-motifs were found in every type of human cell the researchers used in the study.
The researchers also noticed that the green spots, the i-motifs, disappeared and reappeared in the cells.
“We think the coming and going of the i-motifs is a clue to what they do,” said Mahdi Zeraati, the lead author of the study. “It seems likely that they are there to help switch genes on or off, and to affect whether a gene is actively read or not.”
The research opens new doors to future studies on i-motifs that will hopefully reveal more about the structure and its purpose.
3-D printing may soon revolutionize the food industry
What will food of the future look and taste like as agriculture and food distributors work to keep up with the projected increases in population and demand?
The answer to some of these questions may lie in 3-D printing, a quickly developing new technology that takes raw materials and layers them to create three-dimensional objects.
3-D printing has been used to make everything from car parts to gadgets and toys, and even artificial organs. But now, a new study has found promising applications in creating customizable food with 3-D printing.
The study was conducted by researchers from the Ewha Womans University in South Korea and will be presented at the American Society for Biochemistry and Molecular Biology annual meeting in San Diego this month.
“We built a platform that uses 3-D printing to create food microstructures that allow food texture and body absorption to be customized on a personal level,” said Jin-Kyu Rhee. “We think that one day, people could have cartridges that contain powdered versions of various ingredients that would be put together using 3-D printing and cooked according to the user’s needs or preferences.”
The researchers created a prototype 3-D printer that made food with similar properties at the nanoscale of actual food samples.
The prototype was also able to turn carbohydrate and protein powders into food with microstructures and the researchers say this allows for people to control texture and food absorption.
Being able to customize food specifically catered to an individual’s personal nutritional needs could help prevent allergic reactions due to dietary restrictions and ensure that the optimal amount of nutrients were consumed with each meal.
The researchers also note that whether available as a home appliance or used at the industrial level, 3-D printed food could reduce food waste, packaging, and costs of storage and transportation.
It would also help meet the rising food demands as the world’s population increases in the coming years.
The study is exciting and adds to the growing body of research around the many possible applications of 3-D printing.
“We are only in early stages, but we believe our research will move 3-D food printing to the next level,” said Rhee. “We are continuing to optimize our 3-D print technology to create customized food materials and products that exhibit longer storage times and enhanced functionality in terms of body absorption.”
European drought regions would grow under climate change
If global temperatures continue to rise, Europe could soon see larger drought regions, according to a new study from the Helmholtz Centre for Environmental Studies.
The team of scientists from Germany, the Netherlands, the UK and the United States used a modeling program to explore what effects climate change might have on Europe if global temperatures rise more than 1.5 degrees Celsius. That limit is the goal of the landmark Paris Agreement, but scientists are studying what might happen if the agreement fails in its goals.
Using modeling software, the team of researchers looked at how an average global temperature rise of 3 degrees Celsius would affect drought conditions in Europe.
“In the event of a three-degree warming [in Southern Europe], we assume there will be 5.6 drought months per year; up to now, the number has been 2.1 months. For some parts of the Iberian Peninsula, we project that the drought could even last more than seven months,” Dr. Luis Samaniego, one of the study’s two lead authors, said in a press release.
Such a rise in temperatures would expand European drought regions from 13 percent to 20 percent of the continent’s total area, compared to drought activity from 1971 to 2000, the researchers said. More than 400 million people could be affected, they said.
Some regions will be affected more than others, the model showed. The Mediterranean could see drought regions expand from 28 to 49 percent, the scientists said. The loss of water content in the soil could be similar to the 2003 heat wave that ravaged France and central Europe.
But other regions won’t have it as bad.
“In the Atlantic, Continental and Alpine regions, the drought areas will enlarge by less than 10 percent of the total area,” said mathematician Dr. Stephan Thober, the study’s other lead author.
In Scandinavia and the Baltic States, drought regions could even shrink by as much as 3 percent.
If the Paris Agreement countries reach their goal of a global temperature rise of no more than 1.5 degrees Celsius, the potential for drought would still go up from the present day, but the risk would be much lower, the researchers said.
By Kyla Cathey, Earth.com staff writer
Four big breakthroughs presented to improve the environment
Every year, a conference is held with over 14,000 multidisciplinary scientists sharing the newest concepts and research findings relevant to clinical advances. This year’s meeting, Experimental Biology 2018 (EB 2018) will include four innovative studies focused on understanding contamination and improving the environment.
Stephanie Chaousis from Griffith University in Australia will be introducing a technique that may lead to the discovery of biomarkers for detecting contamination exposure in wildlife without the need for invasive sampling.
The new method, which uses cultured cells from animals, was demonstrated in an experiment with green sea turtles. The researchers cultured skin cells and exposed them to two contaminants that commonly accumulate in sea turtles. Using mass spectrometry, the experts identified many proteins that changed expression levels after exposure.
Héctor Rivera from the University of Puerto Rico will be reporting on more sustainable ways to produce biofuel from cooking oil and grease waste. While the enzyme lipase has been found to speed up the conversion process, the enzyme’s activity levels are not high enough for industrial-scale biodiesel production.
Three new nanoparticle formulas, which were developed by the researchers using lipase from the fungus Candida rugosa, were all shown to facilitate faster biodiesel production compared to traditional lipase formulations.
Experts from National University and the Scripps Institute of Oceanography in California set out to identify the harmful bacteria found on ocean plastic. The team submerged three common types of plastics in waters off the coast of Southern California and sequenced the microbial DNA at four intervals throughout the study.
The researchers found that more than 40 percent of the DNA sequences belonged to unknown organisms. Furthermore, all of the plastic materials contained different types of bacteria which were also different from those found in the surrounding seawater. Early testing on the plastics revealed bacteria that can cause disease in humans. The research will be presented at the meeting by Ana Maria Barral.
Researchers from the University of Washington have been investigating the prenatal effects of marine toxin exposure. Domoic acid is a naturally occurring toxin produced by marine algae that can cause fatal central nervous system toxicity in people who consume highly-contaminated shellfish. The effects of long-term exposure to low levels of domoic acid, however, are not known.
The researchers focused a study on 20 pregnant monkeys. After the pregnant females were administered low doses of the neurotoxin over the course of at least two months, the experts found that the fetuses experienced nearly the same domoic acid exposure as the mothers.
Some of the exposed monkeys showed subtle signs of neurological effects, such as tremors. The study authors believe that the government should lower the tolerable daily intake levels of domoic acid until more is known about the human health risks associated with long-term, low-level exposure. The research will be presented by Sara Shum at EB 2018.
Ancient humans began walking upright sooner than was thought
An investigation by researchers at the University of Arizona is providing new insight into the evolutionary history of upright walking. The analysis of 3.6 million-year-old footprints uncovered in Tanzania suggests that hominins were walking with extended legs much earlier than what was previously realized.
“Fossil footprints are truly the only direct evidence of walking in the past,” said David Raichlen, PhD, associate professor at the.
“By 3.6 million years ago, our data suggest that if you can account for differences in size, hominins were walking in a way that is very similar to living humans. While there may have been some nuanced differences, in general, these hominins probably looked like us when they walked.”
The term hominin refers to human relatives that lived before the genus Homo, which were ancestral humans that emerged around 2.5 million years ago.
Hominins started walking on two legs approximately seven million years ago, but scientists have mainly theorized that the extinct humans walked with a crouch and bent legs like other primates of that time.
Based on the fossilized footprints and skeletons of early humans, the researchers used various techniques to reconstruct walking mechanics. The study revealed that the footprints discovered in Tanzania are consistent with the fully upright, bipedal gait of modern humans.
The researchers explained that walking upright with the legs fully extended uses less energy than bipedal walking in a crouched, ape-like fashion. Hominins likely adopted a more upright style of walking to preserve their energy for long foraging journeys.
“The data suggest that by this time in our evolutionary history, selection for reduced energy expenditures during walking was strong,” said Raichlen.
“This work suggests that, by 3.6 million years ago, climate and habitat changes likely led to the need for ancestral hominins to walk longer distances during their daily foraging bouts. Selection may have acted at this time to improve energy economy during locomotion, generating the human-like mechanics we employ today.”
The research was presented at the Experimental Biology 2018 meeting in San Diego.
Scientists can now bend and stretch diamonds
An international team of researchers has discovered that diamonds can actually be flexible in some forms. The experts found that tiny diamond needles can bend and stretch, and then return to their original state.
The scientists used a chemical vapor deposition process to create diamond needles measuring just a few micrometers tall. To investigate how much strain the structures could undergo without breaking, they examined the needles under a scanning electron microscope while applying pressure with a nanoindenter diamond tip.
A computer model developed by the team revealed that the maximum strain that could be endured by the nano samples was 9 percent. After being stretched to their limit, the diamond needles were able to transform back to their original shape.
“It was very surprising to see the amount of elastic deformation the nanoscale diamond could sustain,” said study co-author Daniel Bernoulli of the Massachusetts Institute of Technology.
According to Bernoulli, the stretch limit of a diamond falls way below one percent in its natural state. While diamonds are known for their strength, it is this quality that also causes them to be brittle.
Study senior co-author Yang Lu is an associate professor of Mechanical and Biomedical Engineering at the Chinese University of Hong Kong.
“We developed a unique nanomechanical approach to precisely control and quantify the ultralarge elastic strain distributed in the nanodiamond samples,” said Professor Lu.
The researchers explained that when this type of strain is placed on crystalline materials such as diamonds, it can significantly change their properties.
According to the study authors, this process of “elastic strain engineering” could lead to the development of strong diamond-based materials to be used in a variety of applications such as sensing and data storage devices.
The study is published in the in the journal Science.
Artificial sweeteners, like sugar, can lead to obesity and diabetes
Business is booming for companies that make artificial sweeteners. As more people turn away from sugar for health reasons, sugarless candy, diet sodas and other foods using the sugar replacements have grown in popularity.
But a new study found that replacing sugar with artificial sweeteners may not actually prevent diabetes – or shrink the waistline.
“Despite the addition of these non-caloric artificial sweeteners to our everyday diets, there has still been a drastic rise in obesity and diabetes,” said Dr. Brian Hoffmann of the Medical College of Wisconsin and Marquette University, who led the research. “In our studies, both sugar and artificial sweeteners seem to exhibit negative effects linked to obesity and diabetes, albeit through very different mechanisms from each other.”
Hoffman’s study uses a method dubbed “unbiased high-throughput metabolomics” to look at biochemical changes the human body experiences after eating sugar or artificial sweeteners.
Using rats and cell cultures, the researchers examined how their metabolic profiles were altered by each type of sweetener. They also looked at how sugar and artificial sweeteners affected the lining of blood vessels.
Regardless of the type of sweetener the researchers fed the rats, they saw significant changes in the levels of biochemicals, amino acids and fats in the rats’ blood samples. In addition, one artificial sweetener, acesulfame potassium, appeared to remain concentrated in the rats’ blood, causing damage to the cells that lined their blood vessels.
“We observed that in moderation, your body has the machinery to handle sugar; it is when the system is overloaded over a long period of time that this machinery breaks down,” Hoffmann said in a press release. “We also observed that replacing these sugars with non-caloric artificial sweeteners leads to negative changes in fat and energy metabolism.”
The study showed that both sugar and artificial sweeteners can be harmful to the body, but more research is needed, the researchers said.
Hoffman will present the research at Experimental Biology 2018 in San Diego today. The conference brings together more than 14,000 researchers in a number of clinical fields.
By Kyla Cathey, Earth.com staff writer
Seniors: drinking water during exercise boosts your brain
Drinking water during exercise is a no brainer, right? Actually, it could have plenty of benefits for the brain and cognition, according to a new study of active older adults.
A team of New England-based researchers set out to explore the connection between good hydration and exercise-boosted cognition in seniors.
“Middle-age and older adults often display a blunted thirst perception, which places them at risk for dehydration and subsequently may reduce the cognitive health-related benefits of exercise,” the researchers wrote.
To conduct their study, the scientists recruited recreational cyclists with an average age of 55. By testing the participants’ urine, they placed them into two teams. One team showed signs of dehydration, while the other tested normal.
The teams each completed a “trail-making” activity before and after going for a ride on a warm day. The test involved quickly and accurately linking numbered dots.
Both groups completed the activity more quickly and accurately after exercising on the bike ride. However, the dehydrated group showed much less improvement than the properly hydrated group.
“This suggests that older adults should adopt adequate drinking behaviors to reduce cognitive fatigue and potentially enhance the cognitive benefits of regular exercise participation,” the researchers wrote.
Previous studies have found links between dehydration and impaired exercise function and cognition, but those studies have focused on younger adults, not seniors. However, this adds to a collection of studies that link exercise to better brain power – and that show the importance of drinking water before, during and after exercise.
Experimental Biology is an annual meeting of more than 14,000 scientists and exhibitors. They meet each year to share new advances in clinical research.
By Kyla Cathey, Earth.com staff writer
Humans (and chimps) are genetically inclined to turn to war
Chimpanzees are the only primates known to frequently engage in warfare – other than humans, of course. Knowing this connection of inter-species aggression that humans and chimpanzees share, researchers postulated that the fight-or-flight response probably played a significant role in helping us primates adapt to the threat of warfare during our evolution.
In a recent study published in PLOS Genetics, researchers looked for changes in the regulation of the ADRA2C gene, which affects the sympathetic nervous system, which in turn regulates the fight-or-flight response. Jung Kyoon Choi of KAIST in Korea and Soojin Yi of Georgia Tech analyzed genomes, transcriptomes, and epigenomes from multiple humans, chimpanzees, and other primates. Transcriptomes are the entire set of genes expressed in a cell, while epigenomes are made up of a variety of compounds that can bind to DNA and affect gene expression.
Their results showed that humans and chimpanzees acquired genetic and epigenetic changes that reduce ADRA2C expression, which results in increased signaling for the fight-or-flight response. However, these changes are not present in macaques and are not consistently found in bonobos. This suggests that the genetic variations recently spread in the population may have occurred in response to threats of war, as these variations are only universal in humans and chimpanzees.
The researchers also used the genome-editing technique known as CRISPR/Cas9 in order to show that reverting to the genetic states of macaques and bonobos can restore ADRA2C expression. Knocking out expression of this gene in mice has a significant effect on fight-or-flight, and changes in the gene that happened over time during chicken domestication likely resulted in less aggressive chickens.
So what do these findings mean? The authors believe that the signatures of adaptations linked to reduced ADRA2C expression in both chimps and humans may have significantly influenced their evolution, and may even have played a major role in the roots of human warfare.
Humans can develop a genetic adaptation for diving
For over 1000 years, the Bajau people – a group indigenous to parts of Indonesia – have collected their food by free diving with spears. They are famous throughout the region for their incredible breath-holding abilities, which allow them to free dive to depths up to 70 meters. How can they pull off these extraordinary dives? New research published in the journal Cell has found evidence that this group has genetically adapted to diving, a scientific first.
Scientists had previously hypothesized that our spleens play an integral role in the ability of some humans to free dive for extended periods of time, but until now, the relationship between spleen size and dive capacity has never been studied on a genetic level. The findings of this research suggest that the Bajau have genetically enlarged spleens, which allow them to free dive for so long and at such great depths.
But how does the spleen help someone hold their breath under water? Scientists have known that the spleen plays an important role in free diving, as it forms part of the human dive response. When the human body is submerged under cold water, a response is triggered in order to help the individual survive in this oxygen-deprived environment. The heart rate slows, blood vessels in extremities shrink to save blood for vital organs, and the spleen contracts. This contraction generates an oxygen boost by ejecting red blood cells into circulation – corresponding in as much as a 9 percent increase in oxygen.
“There’s not a lot of information out there about human spleens in terms of physiology and genetics,” says Melissa Ilardo, the first author of the paper. “But we know that deep diving seals, like the Weddell seal, have disproportionately large spleens. I thought that if selection acted on the seals to give them larger spleens, it could potentially do the same in humans.”
Ilardo spent several months in Indonesia, taking genetic samples and performing ultrasound scans of spleens from the Bajau people as well as their land-dwelling neighbors, the Saluan. The results showed that the Bajua have a median spleen size 50 percent larger than the Saluan – a difference visible in non-diving Bajua individuals as well as those who regularly free dive. This finding eliminated the possibility that larger spleens were a more short-term response to diving. Further analysis of the Bajau’s genetic data at the University of Copenhagen discovered that members of this group have a gene called PDE10A, which the Saluan lacked. The researchers believe that the PDE10A gene controls the levels of thyroid hormone T4.
“It’s been shown in mice that thyroid hormones and spleen size are connected,” says Ilardo. “If you genetically alter mice to have an absence of the thyroid hormone T4, their spleen size is drastically reduced, but this effect is actually reversible with an injection of T4.”
This discovery marks the first time that a genetic adaptation to diving has been found in humans. The study also has implications for medical research, as the human dive response simulates the conditions of acute hypoxia – where body tissue experiences a rapid depletion of oxygen. Acute hypoxia is the leading cause of complications in emergency care. Moving forward, this study may lead to a solution that remedies this condition.
“It will help us make the link between the genetics and the physiological response to acute hypoxia,” says Dr. Rasmus Nielsen, who holds dual positions at the University of Copenhagen and the University of California, Berkeley. “It’s a hypoxia experiment that nature has made for us and allows us to study humans in a way that we can’t in a laboratory.”
Image Credit: Melissa Ilardo
Are dogs able to predict earthquakes?
It is not uncommon for people to take anecdotal evidence as proof and unfortunately, urban legends and old sayings are often cited as hard facts.
For example, achy joints supposedly predict changes in the weather for people with arthritis, and animals exhibit strange behaviors before an earthquake leading many to assume they can sense the event coming.
The results, published in the Bulletin of the Seismological Society of America, show that even though animals may be able to sense certain changes in seismic activity, there is no firm evidence proving that dogs, cats, or even farm animals can predict an upcoming earthquake.
The study is the first of its kind to statistically approach the hypothesis about animals and earthquakes, and highlights the difficulties in trying to find proof in single observations and anecdotal evidence.
In order to effectively study the connection between animals and earthquakes, the researchers defined some clear factors that need to be considered but are so often lacking in any currently published research.
These factors included the animal’s distance from earthquakes, if the animal exhibited that same behavior without any earthquakes, if the animals in question are healthy, and if there is a statistical testing hypothesis in place to examine the evidence.
“Many review papers on the potential of animals as earthquake precursors exist, but to the best of our knowledge, this is the first time that a statistical approach was used to evaluate the data,” said Heiko Woith, the study’s lead author.
The researchers gathered and analyzed 729 reports of animal behavior predicting potential earthquakes. Elephants, cows, silkworms, dogs, and cats along with a variety of other animals were all included in the research.
In general, the researchers noticed that most of the reports came from anecdotal evidence and the research mostly focused on three earthquakes, one in New Zealand, one in Japan, and another in Italy.
It was difficult to pinpoint any links between the reports due to a large amount of variation between the events, the types of behaviors, when the behaviors began, and the distance between the animal the origin of the earthquake.
Only 14 of the reports included a series of observations leading up to an earthquake.
According to the study’s authors, research that monitors animal behavior over a long period of time is necessary, as it’s the only way to rule out other environmental changes or factors that could explain the abnormal behaviors.
The researchers could not find any clear evidence to prove that animals can predict earthquakes, but that doesn’t mean that animals aren’t sensitive to seismic activity.
“The animals may sense seismic waves–it could P, S or surface waves–generated by foreshocks,” said Woith. “Another option could be secondary effects triggered by the foreshocks, like changes in groundwater or release of gases from the ground which might be sensed by the animals.”
Woolly mammoths might be making a big comeback
Woolly mammoths, the giant furry mammals that used to roam the Arctic, disappeared off the face of the planet roughly 10,000 years ago. Now, in an almost Jurassic Park type storyline, Harvard University scientists are planning to clone these animals and bring them back from extinction. How will they do this? By using DNA from a 42,000 year-old frozen woolly mammoth, of course!
For this to come to fruition, the scientists would have to grow the mammoth within an artificial womb. The final product wouldn’t be 100% woolly mammoth, but rather a hybrid between an Asian elephant and a mammoth. They could accomplish this feat through a genetic technique known as CRISPR-Cas9, which allows them to “cut and paste” strands of DNA with unparalleled precision. Thus, they would be able to cut and paste preserved mammoth DNA into the DNA of Asian elephants in order to create a mammoth-elephant hybrid.
“We have already revived dozens of genes and are testing them in elephant cells,” says George Church, a professor at Harvard and lead author of the paper. “We are focusing on a reviving mammoth genes and making a mammoth/elephant hybrid and help them spread to vast wild, arctic climates.”
If this plan were to actually work, the mammoths would be able to live in a 20,000 hectare Ice Age safari park created by Russian scientists in a remote region of Siberia. The researchers believe their presence could actually help regenerate Arctic climates through stimulating the growth of vegetation.
“Cold-resistant elephants would flatten the insulating snow and supporting trees in winter and favor the highly heat reflective grass in summer,” says Church. “They would also help capture new carbon by enhancing the photosynthetic capacity of the vegetation.”
Since beginning this project in 2015, the scientists have increased the number of “edits” where mammoth DNA has been spliced into the elephant genome by three-fold.
“We’re working on ways to evaluate the impact of all these edits and are basically trying to establish embryogenesis in the lab. The list of edits affects things that contribute to the success of elephants in cold environments,” Church explains. “We already know about ones to do with small ears, sub-cutaneous fat, hair and blood, but there are others that seem to be positively selected.”
Through these new-age gene editing processes, bringing back extinct species is now a real possibility. “Our aim is to produce a hybrid elephant/mammoth embryo,” says Church. “Actually, it would be more like an elephant with a number of mammoth traits. We’re not there yet, but it could happen in a couple of years.”