CAN MICROBES PASS DNA TO THEIR HOST’S BABIES?

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The DNA of bacteria that live in the body can pass a trait to offspring in a way that’s similar to that of the parents’ own DNA.

The new study with mice puts a wrinkle in Biology 101, which tells us that traits such as eye color and height are passed from one generation to the next through the parents’ DNA.

According to the authors, the discovery means scientists need to consider a significant new factor—the DNA of microbes passed from mother to child—in their efforts to understand how genes influence illness and health.

“We have kept bacteria on one side of a line separating the factors that shape our development—the environmental side of that line, not the genetic side,” says co-senior author Herbert W. Virgin IV, professor of pathology and head of the Department of Pathology and Immunology at Washington University School of Medicine in St. Louis. “But our results show bacteria stepping over the line.

“This suggests we may need to substantially expand our thinking about their contributions, and perhaps the contributions of other microorganisms, to genetics and heredity.”

http://www.futurity.org/dna-bacteria-offspring-859392/

Some earlier articles that show the important role of microbes play in our makeup and health

Microbes maketh man



POLITICAL revolutionaries turn the world upside down. Scientific ones more often turn it inside out. And that, almost literally, is happening to the idea of what, biologically speaking, a human being is.

The traditional view is that a human body is a collection of 10 trillion cells which are themselves the products of 23,000 genes. If the revolutionaries are correct, these numbers radically underestimate the truth. For in the nooks and crannies of every human being, and especially in his or her guts, dwells the microbiome: 100 trillion bacteria of several hundred species bearing 3m non-human genes. The biological Robespierres believe these should count, too; that humans are not single organisms, but superorganisms made up of lots of smaller organisms working together.

It might sound perverse to claim bacterial cells and genes as part of the body, but the revolutionary case is a good one. For the bugs are neither parasites nor passengers. They are, rather, fully paid-up members of a community of which the human “host” is but a single (if dominating) member. This view is increasingly popular: the world’s leading scientific journals, Nature and Science, have both reviewed it extensively in recent months. It is also important: it will help the science and practice of medicine (see article).

All in this together

The microbiome does many jobs in exchange for the raw materials and shelter its host provides. One is to feed people more than 10% of their daily calories. These are derived from plant carbohydrates that human enzymes are unable to break down. And not just plant carbohydrates. Mother’s milk contains carbohydrates called glycans which human enzymes cannot digest, but bacterial ones can.

This alone shows how closely host and microbiome have co-evolved over the years. But digestion is not the only nutritional service provided. The microbiome also makes vitamins, notably B2, B12 and folic acid. It is, moreover, capable of adjusting its output to its host’s needs and diet. The microbiomes of babies make more folic acid than do those of adults. And microbiomes in vitamin-hungry places like Malawi and rural Venezuela turn out more of these chemicals than do those in the guts of North Americans.

The microbiome also maintains the host’s health by keeping hostile interlopers at bay. An alien bug that causes diarrhoea, for instance, is as much an enemy of the microbiome as of the host. Both have an interest in zapping it. And both contribute to the task. Host and microbiome, then, are allies. But there is more to it than that. For the latest research shows their physiologies are linked in ways which make the idea of a human superorganism more than just a rhetorical flourish.

These links are most visible when they go wrong. A disrupted microbiome has been associated with a lengthening list of problems: obesity and its opposite, malnutrition; diabetes (both type-1 and type-2); atherosclerosis and heart disease; multiple sclerosis; asthma and eczema; liver disease; numerous diseases of the intestines, including bowel cancer; and autism. The details are often obscure, but in some cases it looks as if bugs are making molecules that help regulate the activities of human cells. If these signals go wrong, disease is the consequence. This matters because it suggests doctors have been looking in the wrong place for explanations of these diseases. It also suggests a whole new avenue for treatment. If an upset microbiome causes illness, settling it down might effect a cure.

Yogurt companies and health-food fanatics have been banging this drum for years. And in the case of at least one malady, irritable-bowel syndrome, they are right. So-called probiotics, a mixture of about half a dozen bacterial species found in yogurt, do act to calm this condition. But there is little evidence that consuming probiotics has the tonic effect on healthy people that certain adverts suggest.

A handful of doctors are taking a more fundamental approach to another microbiome-related disease, infection with Clostridium difficile. This bacterium, which causes life-threatening distension of the gut in some people who have been treated with antibiotics and thus had their microbiomes disrupted, is a bane of hospitals. It kills 14,000 people a year in America alone. But recent experiments have shown it can be eliminated by introducing, as an enema, the faeces of a healthy individual. “Stool transplants” are a pretty crude approach, to be sure, but the crucial point is that microbes are much easier to manipulate than human cells. For all the talk of superorganisms (and despite the yuck factor of what is being moved from one body to another), transplanting a microbiome is far easier than transplanting a heart or a kidney.

Disgusting but useful

Two other areas look promising. One is more sophisticated deployment of the humble antibiotic, arguably the pharma industry’s most effective invention. At the moment antibiotics are used mainly to kill infections. In the future they might have a more subtle use—to manipulate the mix of bugs within a human, so that good bugs spread at the expense of bad ones.

The other field that may be changed is genetics. Many of the diseases in which the microbiome is implicated seem to run in families. In some, such as heart disease, that is partly explained by known human genes. In a lot, though, most notably autism, the genetic link is obscure. This may be because geneticists have been looking at the wrong set of genes—the 23,000 rather than the 3m. For those 3m are still inherited. They are largely picked up from your mother during the messy process of birth. Though no clear example is yet known, it is possible that particular disease-inducing strains are being passed down the generations in this way.

As with all such upheavals, it is unclear where the microbiome revolution will end up. Doctors and biologists may truly come to think of people as superorganisms. Then again, they may not. What is clear, though, is that turning thinking inside out in this way is yielding new insights into seemingly intractable medical problems, and there is a good chance cures will follow. Vive la révolution!

http://www.economist.com/node/21560559


We’ve long known that that the gut is responsible for digesting food and expelling the waste. More recently, we realised the gut has many more important functions and acts a type of mini-brain, affecting our mood and appetite. Now, new research suggests it might also play a role in our cravings for certain types of food.

http://www.rawstory.com/rs/2014/11/how-the-bacteria-in-your-gut-affects-your-cravings-for-food/comments/#disqus

[1714103848]

1714103848

[BitMos]

the EARTH IS FLAT!

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sometimes answers are found in the most unusual places

Rob Knight: How our microbes make us who we are

https://www.youtube.com/watch?v=i-icXZ2tMRM

Rob Knight is a pioneer in studying human microbes, the community of tiny single-cell organisms living inside our bodies that have a huge — and largely unexplored — role in our health. “The three pounds of microbes that you carry around with you might be more important than every single gene you carry around in your genome,” he says. Find out why.

[RodeoX]

This is such a cool subject and all sorts of new data are pointing toward the role of microbes in our lives. For example I like chocolate. Or do I? Maybe my desire is being manipulated by bacteria who like chocolate?

http://www.ucsf.edu/news/2014/08/116526/do-gut-bacteria-rule-our-minds

P.S. There are several other examples of cross species transfer of DNA. It is not that weird in nature and before multi-cellular life it may have been the norm.

[jaysabi]

This is such a cool subject and all sorts of new data are pointing toward the role of microbes in our lives. For example I like chocolate. Or do I? Maybe my desire is being manipulated by bacteria who like chocolate?

http://www.ucsf.edu/news/2014/08/116526/do-gut-bacteria-rule-our-minds

P.S. There are several other examples of cross species transfer of DNA. It is not that weird in nature and before multi-cellular life it may have been the norm.

I think it's an interesting question to ponder if it actually matters why you "like" something. If you like chocolate because you like the taste of it, or you "like" chocolate because you're manipulated by bacteria which likes chocolate, does it matter in the end if eating chocolate gives you pleasure?

[Mikestang]

Post a link to the peer-reviewed journal the study was published.  Anyone can put anything on the internet, and all your link sources are two other websites, which are not sources.

[TECSHARE]

An interesting side note, if you know how genetic engineering is done, you will know they use sequences of bacterial DNA to insert genes into another life form with a "gene gun". If bacteria can enter the DNA of its host, what is stopping the same thing from happening with DNA from GMO foods?

[RodeoX]

This is such a cool subject and all sorts of new data are pointing toward the role of microbes in our lives. For example I like chocolate. Or do I? Maybe my desire is being manipulated by bacteria who like chocolate?

http://www.ucsf.edu/news/2014/08/116526/do-gut-bacteria-rule-our-minds

P.S. There are several other examples of cross species transfer of DNA. It is not that weird in nature and before multi-cellular life it may have been the norm.

I think it's an interesting question to ponder if it actually matters why you "like" something. If you like chocolate because you like the taste of it, or you "like" chocolate because you're manipulated by bacteria which likes chocolate, does it matter in the end if eating chocolate gives you pleasure?

Yeah. I guess I can still say that I like chocolate. Even if I really like endorphins from bacteria.  

An interesting side note, if you know how genetic engineering is done, you will know they use sequences of bacterial DNA to insert genes into another life form with a "gene gun". If bacteria can enter the DNA of its host, what is stopping the same thing from happening with DNA from GMO foods?

Years ago a friend of mine was working on the human genome project and told me about a tool they use. It sounded like a "gene gun"? He worked with plants and used tiny pellets covered in DNA goo. They literally shot the pellets into leaves on the chance that some of the DNA got stuck in the plant DNA. It sounded to simple to be true.
His dream was to use this technique to create tomato plants that produced THC.  

Post a link to the peer-reviewed journal the study was published.  Anyone can put anything on the internet, and all your link sources are two other websites, which are not sources.

Good point! Here are a few of the many studies underway.
http://www.nature.com/news/2011/110830/full/news.2011.510.html

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3515034/

http://onlinelibrary.wiley.com/doi/10.1111/mec.12888/abstract

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To me the interesting thing is how this requires we rethink what it is that we are, we have for so long thought of ourselves as separate from everything else, but that island self image is now blurred. In a way we are mini gods of a universe we never knew existed.

[Edit]

But the kicker is that we may be the gods over them during our lifetime, but if they affect or DNA, who is the ultimate god? a real catch 22! Truth is always stranger than fiction.

Be kind to your gut or it may take vengeance on your descendants, kinda poetic justice. Perhaps we should have the same control over the descendants of our politicians.

Obamas Kids should be raised by Putin & visa versa, Netanyahu's by the Palestinian leader....etc  

[TECSHARE]

An interesting side note, if you know how genetic engineering is done, you will know they use sequences of bacterial DNA to insert genes into another life form with a "gene gun". If bacteria can enter the DNA of its host, what is stopping the same thing from happening with DNA from GMO foods?

Years ago a friend of mine was working on the human genome project and told me about a tool they use. It sounded like a "gene gun"? He worked with plants and used tiny pellets covered in DNA goo. They literally shot the pellets into leaves on the chance that some of the DNA got stuck in the plant DNA. It sounded to simple to be true.
His dream was to use this technique to create tomato plants that produced THC.  

https://en.wikipedia.org/wiki/Gene_gun

[RodeoX]

An interesting side note...

Years ago a friend of mine ...

https://en.wikipedia.org/wiki/Gene_gun

Wow, that's it. I think I'm going to start loading my own DNA rounds for my carry weapon. Screw with me and I'll make sure your kids get Huntington's disease!

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Mental Health May Depend on Creatures in the Gut



The microbiome may yield a new class of psychobiotics for the treatment of anxiety, depression and other mood disorders

The notion that the state of our gut governs our state of mind dates back more than 100 years. Many 19th- and early 20th-century scientists believed that accumulating wastes in the colon triggered a state of “auto-intoxication,” whereby poisons emanating from the gut produced infections that were in turn linked with depression, anxiety and psychosis. Patients were treated with colonic purges and even bowel surgeries until these practices were dismissed as quackery.

The ongoing exploration of the human microbiome promises to bring the link between the gut and the brain into clearer focus. Scientists are increasingly convinced that the vast assemblage of microfauna in our intestines may have a major impact on our state of mind. The gut-brain axis seems to be bidirectional—the brain acts on gastrointestinal and immune functions that help to shape the gut's microbial makeup, and gut microbes make neuroactive compounds, including neurotransmitters and metabolites that also act on the brain. These interactions could occur in various ways: microbial compounds communicate via the vagus nerve, which connects the brain and the digestive tract, and microbially derived metabolites interact with the immune system, which maintains its own communication with the brain. Sven Pettersson, a microbiologist at the Karolinska Institute in Stockholm, has recently shown that gut microbes help to control leakage through both the intestinal lining and the blood-brain barrier, which ordinarily protects the brain from potentially harmful agents.

Microbes may have their own evolutionary reasons for communicating with the brain. They need us to be social, says John Cryan, a neuroscientist at University College Cork in Ireland, so that they can spread through the human population. Cryan's research shows that when bred in sterile conditions, germ-free mice lacking in intestinal microbes also lack an ability to recognize other mice with whom they interact. In other studies, disruptions of the microbiome induced mice behavior that mimics human anxiety, depression and even autism. In some cases, scientists restored more normal behavior by treating their test subjects with certain strains of benign bacteria. Nearly all the data so far are limited to mice, but Cryan believes the findings provide fertile ground for developing analogous compounds, which he calls psychobiotics, for humans. “That dietary treatments could be used as either adjunct or sole therapy for mood disorders is not beyond the realm of possibility,” he says.

Personality shifts
Scientists use germ-free mice to study how the lack of a microbiome—or selective dosing with particular bacteria—alters behavior and brain function, “which is something we could never do in people,” Cryan says. Entire colonies of germ-free mice are bred and kept in isolation chambers, and the technicians who handle them wear full bodysuits, as if they were in a biohazard facility. As with all mice research, extrapolating results to humans is a big step. That is especially true with germ-free mice because their brains and immune systems are underdeveloped, and they tend to be more hyperactive and daring than normal mice.

A decade ago a research team led by Nobuyuki Sudo, now a professor of internal medicine at Kyushu University in Japan, restrained germ-free mice in a narrow tube for up to an hour and then measured their stress hormone output. The amounts detected in the germ-free animals were far higher than those measured in normal control mice exposed to the same restraint. These hormones are released by the hypothalamic-pituitary-adrenal axis, which in the germ-free mice was clearly dysfunctional. But more important, the scientists also found they could induce more normal hormonal responses simply by pretreating the animals with a single microbe: a bacterium called Bifidobacterium infantis. This finding showed for the first time that intestinal microbes could influence stress responses in the brain and hinted at the possibility of using probiotic treatments to affect brain function in beneficial ways. “It really got the field off the ground,” says Emeran Mayer, a gastroenterologist and director of the Center for Neurobiology of Stress at the University of California, Los Angeles.

Meanwhile a research team at McMaster University in Ontario led by microbiologist Premsyl Bercik and gastroenterologist Stephen Collins discovered that if they colonized the intestines of one strain of germ-free mice with bacteria taken from the intestines of another mouse strain, the recipient animals would take on aspects of the donor's personality. Naturally timid mice would become more exploratory, whereas more daring mice would become apprehensive and shy. These tendencies suggested that microbial interactions with the brain could induce anxiety and mood disorders.

Bercik and Collins segued into gut-brain research from their initial focus on how the microbiome influences intestinal illnesses. People who suffer from these conditions often have co-occurring psychiatric problems such as anxiety and depression that cannot be fully explained as an emotional reaction to being sick. By colonizing germ-free mice with the bowel contents of people with irritable bowel syndrome, which induces constipation, diarrhea, pain and low-grade inflammation but has no known cause, the McMaster's team reproduced many of the same gastrointestinal symptoms. The animals developed leaky intestines, their immune systems activated, and they produced a barrage of pro-inflammatory metabolites, many with known nervous system effects. Moreover, the mice also displayed anxious behavior, as indicated in a test of their willingness to step down from a short raised platform.

Autism connection?
Scientists have also begun to explore the microbiome's potential role in autism. In 2007 the late Paul Patterson, a neuroscientist and developmental biologist at the California Institute of Technology, was intrigued by epidemiological data showing that women who suffer from a high, prolonged fever during pregnancy are up to seven times more likely to have a child with autism. These data suggested an alternative cause for autism besides genetics. To investigate, Patterson induced flulike symptoms in pregnant mice with a viral mimic: an immunostimulant called polyinosinic:polycytidylic acid, or poly(I:C). He called this the maternal immune activation (MIA) model.

The offspring of Patterson's MIA mice displayed all three of the core features of human autism: limited social interactions, a tendency toward repetitive behavior and reduced communication, which he assessed by using a special microphone to measure the length and duration of their ultrasonic vocalizations. In addition, the mice had leaky intestines, which was important because anywhere from 40 to 90 percent of all children with autism suffer from gastrointestinal symptoms.

Then Caltech microbiologist Sarkis Mazmanian and his doctoral student Elaine Hsiao discovered that MIA mice also have abnormal microbiomes. Specifically, two bacterial classes—Clostridia and Bacteroidia—were far more abundant in the MIA offspring than in normal mice. Mazmanian acknowledges that these imbalances may not be the same as those in humans with autism. But the finding was compelling, he says, because it suggested that the behavioral state of the MIA mice—and perhaps by extension autistic behavior in humans—might be rooted in the gut rather than the brain. “That raised a provocative question,” Mazmanian says. “If we treated gastrointestinal symptoms in the mice, would we see changes in their behavior?”

Mazmanian and Hsiao investigated by dosing the animals with a microbe known for its anti-inflammatory properties, Bacteroides fragilis, which also protects mice from experimentally induced colitis. Results showed that the treatment fixed intestinal leaks and restored a more normal microbiota. It also mitigated the tendency toward repetitive behavior and reduced communication. Mazmanian subsequently found that B. fragilis reverses MIA deficits even in adult mice. “So, at least in this mouse model, it suggests features of autism aren't hardwired—they're reversible—and that's a huge advance,” he says.

Limits of research
The human gut microbiome evolved to help us in myriad ways: Gut microbes make vitamins, break dietary fiber into digestible short-chain fatty acids and govern normal functions in the immune system. Probiotic treatments such as yogurt supplemented with beneficial strains of bacteria are already being used to help treat some gastrointestinal disorders, such as antibiotic-induced diarrhea. But there are little data about probiotic effects on the human brain.

In a proof-of-concept study Mayer and his colleagues at U.C.L.A. uncovered the first evidence that probiotics ingested in food can alter human brain function. The researchers gave healthy women yogurt twice a day for a month. Then brain scans using functional magnetic resonance imaging were taken as the women were shown pictures of actors with frightened or angry facial expressions. Normally, such images trigger increased activity in emotion-processing areas of the brain that leap into action when someone is in a state of heightened alert. Anxious people may be uniquely sensitive to these visceral reactions. But the women on the yogurt diet exhibited a less “reflexive” response, “which shows that bacteria in our intestines really do affect how we interpret the world,” says gastroenterologist Kirsten Tillisch, the study's principal investigator. Mayer cautions that the results are rudimentary. “We simply don't know yet if probiotics will help with human anxiety,” he says. “But our research is moving in that direction.”

Strains of Bifidobacterium, which is common in the gut flora of many mammals, including humans, have generated the best results so far. Cryan recently published a study in which two varieties of Bifidobacterium produced by his lab were more effective than escitalopram (Lexapro) at treating anxious and depressive behavior in a lab mouse strain known for pathological anxiety. Although Cryan is optimistic that such findings may point the way to the development of psychobiotics, he is wary of hype. “We still need a lot more research into the mechanisms by which gut bacteria interact with the brain,” he says.

http://www.scientificamerican.com/article/mental-health-may-depend-on-creatures-in-the-gut/

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Fiber-Famished Gut Microbes Linked to Poor Health
While probiotics receive more attention, key fibers remain the workhorses in maintaining a healthy gut microbiome
March 23, 2015 |By Katherine Harmon Courage

KEYSTONE, Colo.—Your gut is the site of constant turf wars. Hundreds of bacterial species—along with fungi, archaea and viruses—do battle daily, competing for resources. Some companies advocate for consuming more probiotics, live beneficial bacteria, to improve microbial communities in our gut, but more and more research supports the idea that the most powerful approach might be to better feed the good bacteria we already harbor. Their meal of choice? Fiber. 

Fiber has long been linked to better health, but new research shows how the gut microbiota might play a role in this pattern. One investigation discovered that adding more fiber to the diet can trigger a shift from a microbial profile linked to obesity to one correlated with a leaner physique. Another recent study shows that when microbes are starved of fiber, they can start to feed on the protective mucus lining of the gut, possibly triggering inflammation and disease.

"Diet is one of the most powerful tools we have for changing the microbiota," Justin Sonnenburg, a biologist at Stanford University, said earlier this month at a Keystone Symposia conference on the gut microbiome. "Dietary fiber and diversity of the microbiota complement each other for better health outcomes." In particular, beneficial microbes feast on fermentable fibers—which can come from various vegetables, whole grains and other foods—that resist digestion by human-made enzymes as they travel down the digestive tract. These fibers arrive in the large intestine relatively intact, ready to be devoured by our microbial multitudes. Microbes can extract the fiber's extra energy, nutrients, vitamins and other compounds for us. Short-chain fatty acids obtained from fiber are of particular interest, as they have been linked to improved immune function, decreased inflammation and protection against obesity.

Today's Western diet, however, is exceedingly fiber-poor by historical standards. It contains roughly 15 grams of fiber daily, Sonnenburg noted. For most of our early history as hunter-gatherers, we were likely eating close to 10 times that amount of fiber each day. "Imagine the effect that has on our microbiota over the course of our evolution," he said.

Your bugs are what you eat
Not all helpful fiber, however, needs to come from the roots and roughage for which our ancestors foraged, new research suggests. Kelly Swanson, a professor of comparative nutrition at the University of Illinois at Urbana-Champaign, and his team found that simply adding a fiber-enriched snack bar to subjects' daily diets could swing microbial profiles in a matter of weeks. In a small study of 21 healthy adults with average U.S. fiber intake, one daily fiber snack bar (containing 21 grams of fiber) for three weeks significantly increased the number of Bacteroidetes bacteria and decreased the number of Firmicutes compared with levels before the study or after three weeks of eating fiber-free bars. Such a ratio—of more Bacteroidetes to fewer Firmicutes—is correlated with lower BMI. The findings were published in the January issue of the American Journal of Clinical Nutrition.

"We've known forever that if you eat a lot of fiber, you lose weight," Swanson says. His and other recent studies suggest that our gut microbes are a key player in this relationship. In addition to identifying groups of bacteria, a genome scan revealed a shifting pattern of genes active in the gut microbes. As fiber consumption increased, the activity of genes associated with protein metabolism declined, a finding that researchers hope will help them understand the complicated puzzle of diet and weight loss. "We're getting closer to what is actually cause and effect," Swanson says.

Feed the microbes so they don't feed on you
As gut microbes are starved of fermentable fiber, some do die off. Others, however, are able to switch to another food source in the gut: the mucus lining that helps keep the gut wall intact and free from infection.

In a recent study presented at the Keystone meeting, Eric Martens of the University of Michigan Medical School, postdoctoral researcher Mahesh Desai and their colleagues found that this fuel switch had striking consequences in rodents. A group of mice fed a high-fiber diet had healthy gut lining, but for mice on a fiber-free diet, "the mucus layer becomes dramatically diminished," he explained at the meeting. This shift might sometimes have severe health consequences. Research by a Swedish team, published last year in the journal Gut, showed a link between bacteria penetrating the mucus layer and ulcerative colitis, a painful chronic bowel disease.

A third group of mice received high-fiber chow and fiber-free chow on alternating days—"like what we would do if we were being bad and eating McDonald's one day and eating our whole grains the next," Martens joked. Even the part-time high-fiber diet was not enough to keep guts healthy: these mice had a mucus layer about half the thickness of mice on the consistently high-fiber diet. If we can extend these results to humans, he said, it "tells us that even eating your whole fiber foods every other day is still not enough to protect you. You need to eat a high-fiber diet every day to keep a healthy gut." Along the same lines, Swanson's group found that the gut microbiomes of his adult subjects reverted back to initial profiles as soon as the high-fiber bars were discontinued.

Martens and his colleagues also observed that mice on the consistently high-fiber diet consumed fewer calories and were slimmer than those on the fiber-free diet, showing that fiber benefits the body in multiple ways. "Studies like this are great because it's getting at the mechanisms to explain why fiber is beneficial," Swanson says.

As all this work underscores, the gut microbiome is exceptionally plastic. Such rapid, diet-influenced changes likely served us well over the course of our evolutionary history—shifting faster than our own physiology could, wrote Justin Sonnenburg and Erica Sonnenburg in a November 2014 article in Cell Metabolism. "In delegating part of our digestion and calorie harvest to our gut residents, the microbial part of our biology could easily adjust to day-to-day or season-to-season variation in available food," they noted. New studies continue to demonstrate that microbial changes due to diet are "largely reversible on short time scales." But the question remains as to how chronic low-fiber intake—over a lifetime or generations—might permanently alter our guts and our health.

http://www.scientificamerican.com/article/fiber-famished-gut-microbes-linked-to-poor-health1/

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Ancient bacteria found in hunter-gatherer guts
By Ann Gibbons 25 March 2015 6:00 am Comments

Eat like a hunter-gatherer and you’ll be healthier—so goes the thinking behind so-called paleo diets. But a new study suggests that humans who live in industrialized societies don’t have the guts to stomach a real hunter-gatherer diet. Compared with hunter-gatherers, industrialized peoples’ intestines have fewer kinds of microbes—and are missing at least one major group of ancient bacteria. Yet even with all of these extra microbes, hunter-gatherers have fewer gut ailments, such as Crohn’s disease, colitis, and colon cancer.

Our bodies are home to trillions of bacteria—collectively known as the microbiome—but it’s unclear how our diet impacts the composition of these tiny organisms. Some studies have detected differences in the types of gut bacteria in obese and thin people, for example, while others have shown that hunter-gatherers harbor more diverse gut bacteria than do people in the industrialized world—a difference that may protect preagricultural communities from Crohn’s disease and colon cancer.

In a new study published online today in Nature Communications, an international team of researchers offers the first comprehensive look at the full-scale diversity of gut microbes in one group of hunter-gatherers and how the bacteria unique to them might function in their guts and affect their health. Anthropologist Cecil Lewis of the University of Oklahoma in Norman and his colleagues set out to detect differences in the core gut bacteria in hunter-gatherers and farmers in Peru, and compared them with residents of Norman. The researchers traveled by canoe upriver into the Amazon to study the diet and health of the Matses community, who are among the last hunter-gatherers in the world; they still hunt monkey, sloth, alligator, and other game, as well as gather wild tubers in the forest and fish in the rivers.

Getting “informed consent” from the Matses to gather their fecal samples, which are the best source of bacteria from the gastrointestinal (GI) tract, was a challenge, Lewis says, so the anthropologists gave the Matses a crash course in bacterial biology by showing them gut microbes under microscope. Once they explained that the gut bacteria lived inside them and could affect their health, one Matses man asked if the gut bacteria were the reason he couldn’t drink milk anymore, even though he could as a child. (The answer is yes, in part, because gut bacteria influence how much gas is produced by people who are lactose intolerant.) The researcher collected samples from 25 Matses and also from 31 Tunapuco, a traditional community of potato farmers from the Andean highlands who also eat guinea pig, pork, lamb, and some cheese from cows. They also collected feces from 23 people living in Norman, mostly academics who eat processed foods, including canned fruits and vegetables and prepackaged meals, as well as meat and dairy products such as milk and cheese.

Back in the lab in Norman, Lewis and his colleagues used state-of-the-art gene sequencing methods that allowed them to get long segments of the gene that is used as the standard for classification and identification of microbes, because it differs in various bacteria. They found that the hunter-gatherers’ and farmers’ gut bacteria were far more diverse than those in the people from Norman. The traditional groups have the most diversity in their microbiomes, including new types of bacteria that have yet to be named and several different strains of Treponema, spirochete bacteria that are usually absent in Western industrialized populations. There are strains of Treponema that cause disease, such as syphilis, but the strains found in the traditional people are more closely related to nonpathogenic strains in other mammals, such as pigs.

The detection of several strains of Treponema in the Matses suggests this type of bacteria has been present in human guts for a long time, because it was also found in the GI tracts of the Hadza hunter-gatherers in Tanzania and in nonhuman primates. “Suddenly a picture is emerging that Treponema was part of core ancestral biome,” says co-author Christina Warinner, an anthropologist at the University of Oklahoma. “What’s really striking is it is absolutely absent, not detectable in industrialized human populations.”

The team’s study also analyzed the function of the gut bacteria and found that the Treponema species in the Matses are most like those in the guts of pigs. There, the microbes play a role in digesting carbohydrates, or sugars. This suggests that the existence of Treponema “is likely a good indicator of a general high level of microbial diversity in the human gut,” says evolutionary anthropologist Stephanie Schnorr of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “Now it seems clear that their function is related to helping metabolize carbohydrates, and this can have a number of benefits and implications for host health.”

The key question now is does the absence of Treponema leave industrialized humans without a valuable player in the metabolism of their food—and the prevention of autoimmune disorders, such as Crohn’s and colitis, for example? “What’s starting to come into focus is that having a diverse gut microbiome is critical to maintaining versatility and resiliency in the gut,” Warinner says. “Once you start to lose the diversity, it may be a risk factor of inflammation and other problems.” And trying to eat like our ancestors may not be enough to get the benefits of a true paleo diet and lifestyle. “So even if you could mimic a true paleo diet, you are still missing ancestral gut bacteria that were involved in food digestion in the paleo gut,” Lewis says.

Posted in Biology, Health The Microbes That Make Us

http://news.sciencemag.org/biology/2015/03/ancient-bacteria-found-hunter-gatherer-guts?rss=1

[Tusk]

High-Fat Diet May Alter Behavior And Brain: Gut Bacteria May Increase Anxiety, Impaired Memory

So often we hear about the negative effects of a high-fat diet: The more fatty foods we eat, the more we put ourselves at risk for diseases, such as obesity and heart disease. But do high-fat foods threaten our psyche, too?

A study recently published in the journal Biological Psychiatry hypothesized a high-fat diet produces changes in health and behavior (partly) by altering a person’s gut microbiota. Prior research suggests “alterations in the microbiome may underlie the host’s susceptibility to illness, including neuropsychiatric impairment” — and present researchers decided to put this theory to the test. The transplanted gut microbiota from mice maintaining a high-fat or control diet to non-obese mice maintain a normal diet.

When evaluating recipient mice for changes in behavior and cognition, the mice who received microbiota from the mice maintaining a high-fat diet experienced increased anxiety, impaired memory, and repetitive behaviors. They also showed “many detrimental effects in the body, including increased intestinal permeability and markers of inflammation.” This is all in addition to signs of inflammation in the brain.

In humans, inflammation in the brain has been linked with severe depression.

"This paper suggests that high-fat diets impair brain health, in part, by disrupting the symbiotic relationship between humans and the microorganisms that occupy our gastrointestinal tracks," Dr. John Krystal, editor of Biological Psychiatry, said in a press release.

In a column for Psychology Today, Dr. Gary L. Wenk, a professor at Ohio State University, said almost everything we consume directly or indirectly effects our brain. The foods we consume in high doses (think coffee and sugar) have immediate effects, while different amino acids and carbohydrates with a high glycemic index, like potatoes and donuts, affect the brain over a period of a few days to weeks. Most studies, however, focus on what happens when we don’t get enough of them, not so much when we overconsume them.

“In truth, no one ever considers these distinctions when eating — we just eat what tastes good,” Wenk said. “Sadly, our brains powerfully reward us when we eat sugar, fat, and salt; thus, there is an oncoming epidemic of obesity-related illnesses. Food has both negative and positive effects, and it all depends upon what you consume, how much you consume, and for how long.”

What’s interesting in the present study is the fact brain function was altered even in the absence of obesity, advancing the existing idea there’s a link between psychiatric conditions and gastrointestinal symptoms. Krystal and his team concluded more research needs to be done, but as is, their findings suggest “the gut microbiome has the eventual potential to serve as a therapeutic target for neuropsychiatric disorders.”

This feels like a good time to remind you not all high-fat foods are bad. Foods, like avocados, walnuts, and wild salmon can help you stay healthy, Dr. Mark Hyman said.

Source: Bruce-Keller, AJ et al. Obese-type Gut Microbiota Induce Neurobehavioral Changes in the Absence of Obesity. Biological Psychiatry. 2015.

http://www.medicaldaily.com/high-fat-diet-may-alter-behavior-and-brain-gut-bacteria-may-increase-anxiety-impaired-327276

[Tusk]

Artificial Sweeteners May Change Our Gut Bacteria in Dangerous Ways
Substances such as saccharin may alter the type of bacteria inside us, could lead to obesity
Mar 17, 2015 |By Ellen Ruppel Shell

Many of us, particularly those who prefer to eat our cake and look like we have not done so, have a love-hate relationship with artificial sweeteners. These seemingly magical molecules deliver a dulcet taste without its customary caloric punch. We guzzle enormous quantities of these chemicals, mostly in the form of aspartame, sucralose and saccharin, which are used to enliven the flavor of everything from Diet Coke to toothpaste. Yet there are worries. Many suspect that all this sweetness comes at some hidden cost to our health, although science has only pointed at vague links to problems.

Last year, though, a team of Israeli scientists put together a stronger case. The researchers concluded from studies of mice that ingesting artificial sweeteners might lead to—of all things—obesity and related ailments such as diabetes. This study was not the first to note this link in animals, but it was the first to find evidence of a plausible cause: the sweeteners appear to change the population of intestinal bacteria that direct metabolism, the conversion of food to energy or stored fuel. And this result suggests the connection might also exist in humans.

In humans, as well as mice, the ability to digest and extract energy from our food is determined not only by our genes but also by the activity of the trillions of microbes that dwell within our digestive tract; collectively, these bacteria are known as the gut microbiome. The Israeli study suggests that artificial sweeteners enhance the populations of gut bacteria that are more efficient at pulling energy from our food and turning that energy into fat. In other words, artificial sweeteners may favor the growth of bacteria that make more calories available to us, calories that can then find their way to our hips, thighs and midriffs, says Peter Turnbaugh of the University of California, San Francisco, an expert on the interplay of bacteria and metabolism.

Bacterial gluttons
In the Israeli experiment, 10-week-old mice were fed a daily dose of aspartame, sucralose or saccharin. Another cluster of mice were given water laced with one of two natural sugars, glucose or sucrose. After 11 weeks, the mice receiving sugar were doing fine, whereas the mice fed artificial sweeteners had abnormally high blood sugar (glucose) levels, an indication that their tissues were having difficulty absorbing glucose from the blood. Left unchecked, this “glucose intolerance” can lead to a host of health problems, including diabetes and a heightened risk of liver and heart disease. But it is reversible: after the mice were treated with broad-spectrum antibiotics to kill all their gut bacteria, the microbial population eventually returned to its original makeup and balance, as did blood glucose control.

“These bacteria are not agnostic to artificial sweeteners,” says computational biologist Eran Segal of the Weizmann Institute of Science in Rehovot, Israel, one of the two scientists leading the study. The investigators also found that the microbial populations that thrived on artificial sweeteners were the very same ones shown—by other researchers—to be particularly abundant in the guts of genetically obese mice.

Jeffrey Gordon, a physician and biologist at Washington University in St. Louis, has done research showing that this relation between bacteria and obesity is more than a coincidence. Gordon notes that more than 90 percent of the bacterial species in the gut come from just two subgroups—Bacteroidetes and Firmicutes. Gordon and his team found several years ago that genetically obese mice (the animals lacked the ability to make leptin, a hormone that limits appetite) had 50 percent fewer Bacteroidetes bacteria and 50 percent more Firmicutes bacteria than normal mice did. When they transferred a sample of the Firmicutes bacterial population from the obese mice into normal-weight ones, the normal mice became fatter. The reason for this response, Gordon says, was twofold: Firmicutes bacteria transplanted from the fat mice produced more of the enzymes that helped the animals extract more energy from their food, and the bacteria also manipulated the genes of the normal mice in ways that triggered the storage of fat rather than its breakdown for energy.

Gordon believes something similar occurs in obese humans. He found that the proportion of Bacteroidetes to Firmicutes bacteria increases as fat people lose weight through either a low-fat or low-carbohydrate diet. Stanford University microbiologist David Relman says this finding suggests that the bacteria in the human gut may not only influence our ability to extract calories and store energy from our diet but also have an impact on the balance of hormones, such as leptin, that shape our very eating behavior, leading some of us to eat more than others in any given situation.

The burning question, of course, is whether artificial sweeteners can truly make humans sick and fat. Segal thinks they probably do, at least in some cases. He and his team analyzed a database of 381 men and women and found that those who used artificial sweeteners were more likely than others to be overweight. They were also more likely to have impaired glucose tolerance. Obesity is, in fact, well known as a risk factor for the development of glucose intolerance as well as more severe glucose-related ailments, such as diabetes.

These patterns do not prove that the sweeteners caused the problems. Indeed, it is quite possible that overweight people are simply more likely than others to consume artificial sweeteners. But Segal's team went further, testing the association directly in a small group of lean and healthy human volunteers who normally eschewed artificial sweeteners. After consuming the U.S. Food and Drug Administration's maximum dose of saccharin over a period of five days, four of the seven subjects showed a reduced glucose response in addition to an abrupt change in their gut microbes. The three volunteers whose glucose tolerance did not dip showed no change in their gut microbes.

Although not everyone seems susceptible to this effect, the findings do warrant more research, the scientists say. The Israeli group concluded in its paper that artificial sweeteners “may have directly contributed to enhancing the exact epidemic that they themselves were intended to fight”—that is, the sweeteners may be making at least some of us heavier and more ill.

A cause-and-effect chain from sweeteners to microbes to obesity could explain some puzzles about obese people, says New York University gastroenterologist Ilseung Cho, who researches the role of gut bacteria in human disorders. He points out that in studies, most people who switch from sugar to low-calorie sweeteners in an effort to lose weight fail to do so at the expected rate. “We've suspected for years that changes in gut bacteria may play some role in obesity,” he says, although it has been hard to pinpoint this effect. But Cho adds that it is clear that “whatever your normal diet is can have a huge impact on the bacterial population of your gut, an impact that is hard to overestimate. We know that we don't see the weight-loss benefit one would expect from these nonnutritive sweeteners, and a shift in the balance of gut bacteria may well be the reason, especially a shift that results in a change in hormonal balances. A hormone is like a force multiplier—and if a change in our gut microbes has an impact on hormones that control eating, well, that would explain a lot.”

Microbes vs. genes
Naturally there are many questions left to answer. Cathryn Nagler, a pathologist at the University of Chicago and an expert on gut bacteria and food allergies, says that the enormous genetic variations in humans make extrapolations from mice suspect. “Still, I found the data very compelling,” she says of the Israeli artificial sweetener study. Relman agrees that rodent studies are not always reflective of what happens in humans. “Animal studies can point to a general phenomenon, but animals in these studies tend to be genetically identical, while in humans, lifestyle histories and genetic differences can play a very powerful role,” he says. The constellation of microbes in a human body is a reflection of that body's particular history—both genetic and environmental.

“The microbiome is a component intertwined in a complex puzzle,” Relman continues. “And sometimes the genetics is so strong that it will override and drive back the microbiota.” Genetic variations might explain why only four of the seven saccharin-fed humans had a change in their gut bacteria, for instance, although genetics is only one of a number of possible factors. And if someone is genetically predisposed to obesity and consumes a diet that promotes that obesity, the microbes might change to take advantage of that diet, thereby amplifying the effect.

The Israeli researchers agree that it is far too soon to conclude that artificial sweeteners cause metabolic disorders, but they and other scientists are convinced that at least one—saccharin—has a significant effect on the balance of microbes in the human gut. “The evidence is very compelling,” Turnbaugh says. “Something is definitely going on.” Segal, for one, is taking no chances: he says that he has switched from using artificial to natural sweetener in his morning coffee.

ABOUT THE AUTHOR(S)
Ellen Ruppel Shell is author, most recently, of Cheap: The High Cost of Discount Culture and is co-director of the Graduate Program in Science Journalism at Boston University.
This article was originally published with the title "Artificial Sweeteners Get a Gut Check."

http://www.scientificamerican.com/article/artificial-sweeteners-may-change-our-gut-bacteria-in-dangerous-ways/

[RodeoX]

Thanks for posting this. I'm traveling this week and trying to read it on my phone. When I get home I'm going to re-read all this. 

[tarzan2]

really nice selection of articles Tusk.. each is significant with vast implications about organisms.. for instance the last one tells us that mice apparently have an affinity for artificial sweetner muncher bacteria with unique glycolitic pathways.. now the question remains, do we share such an affinity? since apparently there exist bacteria that can eat stuff we cant, maybe mice reactively digest certain bacteria we cannot.. tho thats more verging on wishful thinking than reason. anyways it raises interesting questions.

i read through most these sources on occasion, but you found the gems

[Tusk]

Thanks Tarzan, i'm fascinated as to how we now beginning to see things are not compartmentalised but rather a synergistic balance, you cant just Add "B" to "A" to get "AB" so to speak. Big pharma has for too long looked at health from a predominantly chemical perspective. This new research is refreshing in that it points to a more holistic understanding. Increasingly it emerging that we are products of the environment and biosphere each part dependant on the rest and influencing each others well being as well as the whole. Kinda zen. The boundaries of where does one thing start and end are becoming less distinct. It makes sense that, as with macrocosm so it is with the microcosm.  The biosphere is a homogeneous soup of living expressions of varying degrees of consciousness, driven by cycles of energy/entropy and oxidation/reduction, amongst others.

[Tusk]

Bundle Of Joyful Microbes: Mom's DNA Alters Baby's Gut Bacteria

Right after birth, trillions of microbes rush into a baby's gut and start to grow. Most of these critters come from the mom's skin, birth canal and gut.

But exactly which types of bacteria take up residence in an infant's gut can depend on the mother's DNA, scientists reported Thursday.

The study, published in the journal Microbiome, focuses on a microbe called Bifidobacterium that potentially benefits babies.

"It plays a role in preventing infections," says Zachery Lewis, a graduate student in microbiology at the University of California, Davis, who contributed to the study. "Bifidobacteria sort of push other bacteria out. They lower the gut's pH, which a lot of pathogens don't like."

After birth, Bifidobacterium is one of the first microbes to arrive in a baby's gut. But not all infants get the microbe at the same time — or in the same amounts.

Now Lewis and his colleagues have figured out why: A single gene in the mom controls the behavior of Bifidobacterium, and that gene works through breast milk.

Women have a whole suite of genes that control the precise recipes of their breast milk, Lewis says. One gene, called FUT2, manufactures a special sugar that Bifidobacterium loves to eat. But about 20 percent of women have a mutation in this gene. So those women make much less of the special sugar.

Lewis and his colleagues thought perhaps this mutation might affect how much Bifidobacteria live in a baby's gut. And they were right.

The study was small — only 44 women. Twelve had the mutation in the special sugar-making gene and 32 didn't. But the findings were clear.

Babies whose moms carry the mutation had about 10 times fewer Bifidobacteria in their guts, on average, than the babies whose moms had a working version of the gene. The former also tended to pick up the bacteria later.

"I think it's exciting how just a single gene is enough to change the baby's microbiome," Lewis says. "It shows that establishing the microbiome is an intricate process, orchestrated by the breast milk."

But the finding comes with many caveats. The team didn't analyze whether the boost in Bifidobacteria had any health effects on the baby. And a whole slew of other factors influence which critters live in a baby's gut. In particular, babies pick up the microbes around them.

"If you're living in an unhygienic home, the baby will have a completely different microbiome than one in a home that gets Cloroxed every day," Lewis says. "Our findings are for babies living in Davis, California. The gene could have totally different effects in other parts of the world."

Lewis says FUT2 is only one of many genes that likely help establish an infant's microbiome.

"We definitely don't want any mothers to think that their breast milk is any less healthy or valuable [if they have the mutation]," he says.

And it's not always possible to breast-feed, while some women choose not to. That's one reason why some scientists are studying how breast milk works, Lewis says: to help make better formula.

http://www.npr.org/blogs/health/2015/04/10/398386277/bundle-of-joyful-microbes-moms-dna-alters-babys-gut-bacteria?utm_medium=RSS&utm_campaign=science