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Early antibiotic exposure linked to later-life obesity, metabolic abnormalities

w study suggests that antibiotic exposure during early life may lead to permanent changes in the gut, increasing the risk of later-life obesity and metabolic abnormalities.
Girl measuring waist
Could exposure to antibiotics early in life increase the risk of obesity later in life? This latest research suggests so.

The research team, led by Laura M. Cox, PhD, of the NYU Langone Medical Center in New York, NY, recently published their findings in the journal Cell.

Past research has associated early antibiotic use with a number of subsequent medical conditions. Last year, Medical News Today reported on a study claiming that antibiotic use within the first year of life increases the risk of eczema by 40%, while a more recent study suggests infant antibiotic use may increase the risk of asthma later in life.

Both of these studies claim antibiotics interfere with beneficial gut bacteria, making infants more prone to the said conditions.

And in this latest study, Dr. Cox and colleagues report a similar theory. They found that mice given antibiotics early in life had altered gut bacteria, which reprogrammed their metabolism and made them more prone to weight gain.

Mice exposed to antibiotics in the womb had higher fat mass

To reach their findings, the researchers conducted a series of experiments on six different mouse models over 5 years.

In one experiment, the team tested low doses of penicillin on three groups of mice. The first group was exposed to antibiotics in the womb during the last week of pregnancy and continued with the antibiotics throughout their lifespan. The second group was first exposed to the penicillin at weaning and received it for life, while the third group received no antibiotics.

fat mouse
Mice that began receiving penicillin in the womb had the highest increase in fat mass, indicating that “mice are more metabolically vulnerable if they get antibiotics earlier in life.”

Dr. Cox and colleagues found that both groups that received the penicillin experienced increased fat mass. However, this gain in body fat was higher among the mice that began receiving penicillin in the womb. “This showed that mice are more metabolically vulnerable if they get antibiotics earlier in life,” says Dr. Cox.

Furthermore, when the mice were fed a high-fat diet, those that received antibiotics became fatter than those left untreated.

“When we put mice on a high-calorie diet, they got fat. When we put mice on antibiotics, they got fat. But when we put them on both antibiotics and a high-fat diet, they got very, very fat,” explains senior author Dr. Martin Blaser, professor of microbiology at the NYU Langone Medical Center.

Adult female mice usually carry around 3 g of fat. The mice fed the high-fat diet alone carried 5 g of fat. But those fed the high-fat diet in combination with antibiotics carried 10 g of fat, which accounted for a third of their body weight.

In addition to this weight gain, these mice also had high levels of fasting insulin and gene alterations linked to liver regeneration and detoxification. These effects, the researchers say, are normally found in obese patients with metabolic disorders.

The team says these findings confirm the results of a study they conducted in 2012, which found that mice given low doses of antibiotics throughout life gained 10-15% more body fat and displayed an altered metabolism in their liver, compared with mice given no antibiotics.

The next step for the researchers was to determine the mechanisms behind these effects. Are they caused by the antibiotics themselves? Or is altered gut bacteria to blame?

Weight gain ‘a result of altered gut bacteria, not antibiotics’

To find out, Dr. Cox and colleagues took gut bacteria from the mice that had been exposed to penicillin and transferred it into the guts of 3-week-old mice (the equivalent to weaning age in human infants) that had been specially bred to be germ- and antibiotic-free.

As a control, another group of specially bred mice received bacteria from mice that had not been treated with penicillin.

The researchers found that the mice that received bacteria from penicillin-treated mice became fatter than those that received bacteria from untreated mice, indicating that increased fat mass is a result of altered gut bacteria rather than the antibiotics themselves.

The team notes that contrary to previous studies investigating the link between antibiotics and gut bacteria, their research revealed that penicillin did not reduce the amount of bacteria in the gut.

However, they found that the antibiotic did abolish four bacteria they say are important for microbial colonization in early life: Lactobacillus, Allobaculum, Candidatus Arthromitus, and a member of theRikenellaceae family that is currently unnamed.

Speaking of the importance of these findings, Dr. Cox says:

“We’re excited about this because not only do we want to understand why obesity is occurring, but we also want to develop solutions.

This gives us four potential new candidates that might be promising probiotic organisms. We might be able to give back these organisms after antibiotic treatments.”

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Memories of error ‘improve our learning speed’

Researchers at Johns Hopkins Medicine in Baltimore, MD, think they have discovered why people learn an identical task faster on subsequent attempts. Publishing their findings in Science Express, the team says our memories of error are the key to faster learning.
illustration of brain activity
The scientific name for the small differences between our expectations of an action and the reality of that action is “prediction errors.”

The researchers note that when people perform a task – such as opening a door – their brains make comparisons of how the door moved with how they expected the door to move. This information is calculated in a way that allows the person to perform the task more efficiently next time.

The scientific name for the small differences between our expectations of an action and the reality of that action is “prediction errors.” We learn prediction errors in a largely unconscious way.

To further investigate how the brain learns prediction errors, the researchers devised an experiment involving a joystick and a pair of dots on a screen.

The participants were told to guide a blue dot toward a red dot on the screen using the joystick. However, the participants were unable to see the joystick that they were holding, and the blue dot could also be programmed by the researchers to move in an off-kilter way.

To overcome the off-kilter movement of the dot, the participants were required to compensate their joystick movements accordingly. Typically, after a few attempts, they would adjust their movements to guide the blue dot to its target.

The researchers observed that the participants responded more quickly to small errors that pushed them consistently in one direction than to larger errors that were less consistent.

David Herzfeld, a graduate student in Shadmehr’s laboratory who led the study, explains: “They learned to give the frequent errors more weight as learning cues, while discounting those that seemed like flukes.”

Reza Shadmehr, PhD, a professor in the Department of Biomedical Engineering at Johns Hopkins, compares the experiment to his proficiency as a tennis player.

“I’m much better in my second 5 minutes of playing tennis than in my first 5 minutes,” he says, “and I always assumed that was because my muscles had warmed up. But now I wonder if warming up is really a chance for our brains to re-experience error.”

‘Two processes happening simultaneously’

Further explaining the experience of learning a new motor task, Dr. Shadmehr says there appear to be two processes happening simultaneously. One of these is the learning of motor commands, and the other is critiquing the learning, “much the way a ‘coach’ behaves.”

“Learning the next similar task goes faster, because the coach knows which errors are most worthy of attention. In effect, this second process leaves a memory of the errors that were experienced during the training, so the re-experience of those errors makes the learning go faster.”

Daofen Chen, PhD, a program director at the National Institute of Neurological Disorders and Stroke, who co-funded the study, says that the research is a significant step toward understanding how we learn motor skills:

“The results may improve movement rehabilitation strategies for the many who have suffered strokes and other neuromotor injuries.”

In the next component of the research, the team will examine which brain region is responsible for the “coaching” role in assigning different weights to various types of error.


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Could household detergents reduce fertility?

Two active ingredients commonly found in household detergents caused reproductive decline in mice, according to a new study published in the journalReproductive Technology, prompting concerns about how these ingredients affect reproduction in humans.
cleaning products
Two chemicals commonly found in household detergents – ADBAC and DDAC – were found to cause reproductive decline in mice.

This is not the first time commonly used chemicals have been found to interfere with reproduction. Last year, Medical News Today reported on a study by researchers from Brigham and Women’s Hospital in Boston, MA, suggesting bisphenol A (BPA) – a chemical used to make plastics and other resins –may cause infertility in women.

In this latest study, led by Dr. Terry Hrubec of the Virginia-Maryland College of Veterinary Medicine, researchers found that two chemicals – alkyl dimethyl benzalkonium chloride (ADBAC) and didecyl dimethylammonium chloride (DDAC) – had a similar effect in mice.

These chemicals are present in an abundance of products that we come into contact with every day, such as household cleaners, disinfectants, hand sanitizers, fabric softeners and even preservatives in cosmetics. But the effect they have on humans is a mystery.

“It is likely that you have these chemicals in your house,” says Dr. Hrubec. “The answer to the question, ‘Are these chemicals harmful to humans?’ is that we simply don’t know.”

ADBAC and DDAC caused reproductive decline in mice

According to Dr. Hrubec, ADBAC and DDAC have never been subject to rigorous safety or toxicity testing, as research investigating these chemicals took place in the 1950s and 1960s before toxicity studies were standardized.

“In the 1980s, toxicity researchers developed and implemented Good Laboratory Practices, or GLPs,” explains Dr. Hrubec. “These are guidelines and rules for conducting research so that it is reproducible and reliable. All of the research on these chemicals happened before that.”

But an observation in her laboratory led her to believe these compounds should be subject to more vigorous testing.

After seeing reproductive decline in her mice, she noticed that her laboratory staff were washing their hands with a disinfectant that contained ADBAC and DDAC prior to touching them. This observation led her to a study conducted by Patricia Hunt, of Washington State University, which reported the same finding.

Dr. Hrubec and Hunt, along with colleagues from Washington State and Virginia-Maryland College of Veterinary Medicine, decided to investigate the association further.

They found that when female mice were exposed to ADBAC and DDAC – which belong to a class of chemicals called quaternary ammonium compounds – they took much longer to become pregnant, and when they did conceive, they gave birth to fewer babies. Furthermore, 40% of female mice exposed to these chemicals died in late pregnancy or during delivery.

Dr. Hrubec notes that although these chemicals appear to be toxic to mice, it cannot yet be said if they would have the same effect in humans.

But given the widespread use of these compounds in products that we are frequently exposed to, she believes further research into their potential implications for human reproduction is warranted.

Dr. Hrubec adds:

“If these chemicals are toxic to humans, they could also be contributing to the decline in human fertility seen in recent decades, as well as the increased need for assistive reproductive technologies such as in vitro fertilization (IVF).”

She suggests that an epidemiological study could help find out whether women highly exposed to ADBAC and DDAC – such as health care workers – have more difficulty becoming pregnant.

Earlier this year, Medical News Today reported on a study suggesting that chemicals found in toothpaste and sunscreen may interfere with sperm function, potentially affecting fertilization.


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Could your workout charge your smartphone?

one day, your morning gym workout or jog could not only be recharging you, but also recharging your smartphone or other small electronic device. Scientists have developed a biosensor mounted inside a temporary tattoo that can monitor the wearer’s progress as they exercise and harness their sweat to produce electrical power.
woman exercising and playing music through smartphone
Biobatteries recharge more quickly than conventional batteries, they use renewable energy, and they do not explode or leak toxic chemicals.

The innovation is the work of a team led by Joseph Wang, Distinguished Professor and Chair of Nanoengineering at the University of California. They presented their novel biobattery approach at a recent meeting of the American Chemical Societyin San Francisco.

Compared with conventional batteries, biobatteries have several advantages: they recharge more quickly, they use renewable energy (in this case body sweat), and they do not explode or leak toxic chemicals.

Prof. Wang says their work shows “the first examples of epidermal electrochemical biosensing and biofuel cells that could potentially be used for a wide range of future applications.”

As we sweat, we produce lactate, “a very important indicator of how you are doing during exercise,” says Dr. Wenzhao Jia, a postdoctoral student in Prof. Wang’s lab.

Generally, the more intensely we exercise the more lactate we produce, as aerobic respiration is not enough to produce the energy we need, and anaerobic respiration kicks in. Anaerobic respiration converts glucose or glycogen to lactic acid, generating energy in the process.

Professional athletes monitor their lactate levels to evaluate their fitness and training performance. Doctors also asses lactate levels during exercise to test patients for heart or lung disease, and other conditions marked by unusually high lactate.

Non-invasive, real-time measure of lactate levels during exercise

Dr. Jia and her colleagues have developed a faster, easier and non-invasive way to measure lactate during exercise in real time. Before their innovation, the only way to do this was by taking blood samples at regular intervals during exercise and sending them away for analysis.

The new sensor, which can be imprinted onto a temporary tattoo, contains an enzyme that produces a weak electrical current by stripping electrons from lactate molecules.

The scientists tested the new device on 10 healthy volunteers. They applied the temporary tattoos to the upper arms of the volunteers and measured how much electrical current they produced as they exercised.

The volunteers exercised on stationary bikes for 30 minutes, with resistance gradually increasing over the period. The sensors allowed the scientists to monitor sweat lactate levels as they changed with exercise intensity.

Biobattery uses lactate from sweat to generate power

The team then developed the technology a stage further and made a sweat-powered biobattery.

They used the enzyme that strips the lactate of electrons to act as the anode, and used a chemical that accepts the electrons to be the cathode. Electrons moving from an anode to a cathode is the basic principle on which a battery works.

To see how the device works, play the video below.

The team tested the biobattery on 15 volunteers exercising on stationary bikes. As before, the device was incorporated within a temporary tattoo applied to their upper arms.

The different volunteers produced varying amounts of power in their tattoo biobatteries. Curiously, the less fit volunteers appeared to produce the most power. Those who exercised only once a week produced more power than those who exercised at least three times a week.

One possible explanation is that less fit people become fatigued more quickly, causing lactate-producing anaerobic respiration to kick in earlier.

The less fit volunteers produced around 70 μW per square cm (cm2) of skin. Dr. Jia says this is not a large amount of current, but they are working on how to to enhance it so it could eventually be enough to power small electronic devices:

“Right now, we can get a maximum of 70 μW per cm2, but our electrodes are only 2 by 3 millimeters in size and generate about 4 μW – a bit small to generate enough power to run a watch, for example, which requires at least 10 μW.”

She says they also need to find a way to store the generated current.

The National Science Foundation and Office of Naval Research are funding the work.


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Sharks Keep Attacking Google’s Deep-Ocean Internet Cables

Just when you thought it was safe to run internet cables in the water, it appears sharks have developed the taste for data.

A Google project manager named Dan Belcher reportedly told attendees at a company marketing event in Boston last week that sharks like to chomp on the fiber optic internet cables Google runs along the ocean floor to connect the continents, according to Network World, which first reported the story. It’s such a problem that the company is wrapping its cables under the Pacific Ocean in a coating similar to Kevlar, the tough synthetic material used to make ballistic vests and body armor.

Google doesn’t have much to say about why sharks would want to chow down on the internet. One possible reason, George Burgess of the Florida Program for Shark Research tells USA Today, is that sharks can detect electromagnetic fields. It’s a talent called electroreception, which allows them to pick up on faint electrical signals that fish emit. Sharks might be confused by the signal that escapes from the cable and think it is prey. 

However, Chris Lowe from the Shark Lab at California State University, Long Beach, says there’s another explanation: Sharks just like to bite things. They’d probably attack a simple piece of plastic in the shape of a cable, he tells Wired

Here’s a video of a shark attack on a submarine cable: 

 

 

Whatever the reason, the problem isn’t new. There have been reports of sharks attacking fiber optic cables ever since companies starting laying them in the ocean in the 1980s. According to a report from the International Cable Protection Committee, the first deep ocean fiber optic cable, built in 1989, failed on four separate occasions because of shark attack. “Bites tend to penetrate the cable insulation, allowing the power conductor to ground with seawater,” it says.

Wrapping undersea cables in many protective layers is now standard operating procedure for Google, and for good reason: There’s a lot of money to be made in providing faster transmission speeds to Asia. Google is currently building multiple lines to the continent, including one $300 million cable that would connect U.S. west coast cities including Los Angeles and Seattle to Japan. 

 


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Father-son mathematicians fold math into fonts: MIT’s Erik and Martin Demaine create puzzle typefaces to test new ideas

Martin Demaine and Erik Demaine

A mathematician once posed a deceptively simple question. Can a single 2-D conveyor belt be stretched around a set of wheels such that the belt is taut and touches every wheel without crossing itself?

MIT computer scientist Erik Demaine pondered the problem. For just a few wheels, the solution is easy: Arrange four into a square, wrap the belt around the outside, and the problem is solved — one version of it, at least.

“The question is whether it’s always possible to solve no matter how you draw the wheels,” Demaine says. A complete solution would lay out a set of rules that applies to every possible wheel arrangement and number. “But so far every algorithm we’ve come up with has been foiled.”

One day Demaine was working on the problem with his dad, who happens to be an artist and mathematician, and a colleague. The trio got stuck. So they decided to take a break with another activity the Demaines enjoy: designing new fonts. The team stuck thumbtacks into poster board to represent wheels, and wrapped them with rubber band “conveyor belts” to form letters.

science news created in conveyor belt and glass font

SECRET MESSAGE By erasing the black lines wrapped around the pink dots in the conveyor belt font (left), puzzle enthusiasts can craft hidden messages from seemingly random clusters of circles. The glass-squishing font (right) can also hide words; users reveal individual letters by imagining what happens after a set of balls and thin rods of glass are pushed or “squished” from the sides.

E. DEMAINE

“It became a game,” Demaine says. “One of us would put in some thumbtacks, and the other would say, “Oh, I see, it’s a ‘K’!”

Demaine and his father, MIT artist-in residence Martin Demaine, published the complete alphabet of conveyor belt letters in the Proceedings of the 7th International Conference on Fun with Algorithms in July along with four other typeface ideas sparked by math and computational geometry. The Demaines’ interest in geometric folding spurred creation of three fonts, one of which — the “origami maze” typeface — uses a computer algorithm to create crease patterns that can fold into 3-D letters.

Several of the Demaines’ fonts can be turned into geometry or math puzzles. In the conveyor belt font, for example, take the belt away from a letter and all that’s left is a cryptic arrangement of wheels. “You can hide secret messages this way,” Erik Demaine says.

Another puzzle font, called the glass-squishing typeface, drew inspiration from their passion for glass blowing. After inventing a software program that helps glass blowers design pieces, the Demaines wanted to mathematically describe how pieces of glass squish together when heated. They started experimenting by making actual glass letters.

The duo arranged blue glass sticks around clear discs, popped the patterns into a volcano-hot oven and then pushed the softened pieces together. “We’d say, ‘Ah, I think this will make an ‘A,’ ” Demaine says, “Then we’d squish it and it would come out looking nothing like an ‘A’.”

After a week of experiments, they posted videos of the full alphabet on Demaine’s website (see erikdemaine.org/fonts). Now, they’re hoping to use what they have learned with the letters to build new software for their virtual glass program.

Demaine thinks the fonts are a fun way to introduce people to the world of computational geometry.

 “We want people to play with the fonts,” he says. “We really love puzzles — now anyone can participate.” 

A mishmash of what looks like sticks and bubbles morphs into letters that spell the words “Science News” in a font inspired by glass blowing. Once the glass sticks heat up, metal bars squish the pieces together around glass discs, forming letters. Credit: E. Demaine and M. Demaine


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Plants “Communicate” Using Molecular Language

Researchers may have discovered a previously unknown form of plant chatter that allows parasitic species and their hosts to share an astonishing amount of genetic information. The finding is exciting not only because it opens up an intriguing new field of research, but it could also lead to the development of novel strategies to tackle parasitic weeds that threaten food crops. The study has been published in Science.

It’s been known for some time that bits of information-containing material can shuffle between cells of a single plant. This material, which is called RNA, is produced from DNA and is used in the production of proteins. While this intercellular RNA movement has been studied extensively, scientists had not explored whether RNA transfer could occur between species until now.

For the present study, Virginia Tech researchers chose to investigate information sharing between a parasitic plant, dodder (C. pentagona), and two hosts- the model plant Arabidopsis and tomatoes. To find out what was being exchanged, the researchers sequenced the transcriptomes of the organisms. The transcriptome is the range of different RNA molecules expressed by an organism. Unlike an organism’s genome (DNA), the transcriptome actively changes depending on a variety of factors, such as environmental conditions.

The team was particularly interested in one type of RNA, called messenger RNA (mRNA), which acts as a template for protein synthesis. mRNA is often very unstable and readily broken down, so the researchers did not anticipate that it could easily transfer between species.

Much to their surprise, the scientists discovered that during this parasitic relationship, thousands of mRNAs were moved between the species in a bidirectional manner. These mobile transcripts represented thousands of different genes. Remarkably, almost half of Arabidopsis’s expressed transcriptome was found in the parasitic plant.

“The discovery of this novel form of inter-organism communication shows that this is happening a lot more than anyone has previously realized,” read researcher Jim Westwood said in a news-release. “Now that we have found they are sharing all this information, the next question is, ‘What exactly are they telling each other?’”

The researchers speculate that this molecular communication may allow the parasitic plant to influence the host, for example instructing it to dampen its defense responses so that it is more vulnerable to attack by the parasitic plant.  

According to Sheffield University researcher Julie Scholes, who was not involved in the study, this finding could be very useful if researchers could use it to develop strategies that disrupt this flow of information. This could potentially help to control parasitic plants that wreak havoc in food crops.