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Scientists reveal how gut microbes 'recover' after antibiotic treatment -- ScienceDaily

We also saw that as antibiotics removed bacteria and reduced their metabolic rates in the mouse gut, there was an increase in oxidising agents called electron acceptors," Reese explains. "This new environmental state meant that the microbial community which recolonised after treatment looked very different from the original community." The bacteria that appeared immediately following treatment, including some potentially harmful species, were able to take advantage of the electron acceptors to grow quickly. As they grew, they used up the excess resources, causing the gut environment to return to its normal state. However, this did not guarantee recovery of the original microbial community. "Antibiotics may drive some microbe species extinct in a gut community, so new microbial immigrants from outside the mouse -- in this case from an untreated mouse in the same cage -- were likely needed to return the microbiota to its original state," says senior author Lawrence David, Assistant Professor of Molecular Genetics and Microbiology at Duke University.

Eating Salad Every Day Keeps Brains 11 Years Younger and Prevents Dementia, Study Shows

Nutritional epidemiologist Martha Clare Morris and her team at Rush University Medical Center in Chicago found that people who ate one to two servings of leafy green vegetables each day experienced fewer memory problems and cognitive decline compared to people who rarely ate spinach. In fact, Morris estimates that veggie lovers who included about 1.3 servings a day into their diets had brains that were roughly 11 years younger compared to those who consumed the least amount of foods like spinach or kale.

Exercise changes gut microbial composition independent of diet, team reports -- ScienceDaily

In the mouse study, changes in the microbiota of recipient mice mirrored those in the donor mice, with clear differences between those receiving microbes from exercised and sedentary mice. "That proved to us that the transplant worked," Woods said. Recipients of the exercised mouse microbiota also had a higher proportion of microbes that produce butyrate, a short-chain fatty acid that promotes healthy intestinal cells, reduces inflammation and generates energy for the host. They also appeared to be more resistant to experimental ulcerative colitis, an inflammatory bowel disease. "We found that the animals that received the exercised microbiota had an attenuated response to a colitis-inducing chemical," Allen said. "There was a reduction in inflammation and an increase in the regenerative molecules that promote a faster recovery." In the human study, the team recruited 18 lean and 14 obese sedentary adults, sampled their gut microbiomes, and started them on an exercise program during which they performed supervised cardiovascular exercise for 30-60 minutes three times a week for six weeks. The researchers sampled participants' gut microbiomes again at the end of the exercise program and after another six weeks of sedentary behavior. Participants maintained their usual diets throughout the course of the study. Fecal concentrations of SCFAs, in particular butyrate, went up in the human gut as a result of exercise. These levels declined again after the participants reverted to a sedentary lifestyle. Genetic tests of the microbiota confirmed that this corresponded to changes in the proportion of microbes that produce butyrate and other SCFAs. The most dramatic increases were seen in lean participants, who had significantly lower levels of SCFA-producing microbes in their guts to begin with. Obese participants saw only modest increases in the proportion of SCFA-producing microbes. The ratios of different microbes in the gut also differed between lean and obese participants at every stage of the study, the researchers said. "The bottom line is that there are clear differences in how the microbiome of somebody who is obese versus somebody who is lean responds to exercise," Woods said. "We have more work to do to determine why that is."

Antibiotics found to weaken body's ability to fight off disease -- ScienceDaily

"Neutrophils play an important role as a first-line 'innate immune response' when foreign pathogens invade," said researcher Koji Watanabe, PhD. "We found that antibiotic disruption of the natural microbes in the gut prevented this from happening properly, leaving the gut susceptible to severe infection."

‘Young poo’ makes aged fish live longer : Nature News & Comment

To test whether the changes in the microbiome had a role in ageing, Valenzano’s team ‘transplanted’ the gut microbes from 6-week-old killifish into middle-aged 9.5-week-old fish. They first treated the middle-aged fish with antibiotics to clear out their gut flora, then placed them in a sterile aquarium containing the gut contents of young fish for 12 hours. Killifish don’t usually eat faeces, Valenzano notes, but they would probe and bite at the gut contents to see whether it was food, ingesting microbes in the process. The transplanted microbes successfully recolonized the guts of the fish that received them, the team found. At 16 weeks of age, the gut microbiomes of middle-aged fish that received 'young microbes' still resembled those of 6-week-old fish.   The young microbiome ‘transplant’ also had dramatic effects on the longevity of fish that got them: their median lifespans were 41% longer than fish exposed to microbes from middle-aged animals, and 37% longer than fish that received no treatment (antibiotics alone also lengthened lifespan, but to a lesser extent).

World-first trial shows improving diet can treat major depression - Medical News Today

The results of the study, published in the international journal BMC Medicine, showed that participants in the dietary intervention group had a much greater reduction in their depressive symptoms over the three-month period, compared to those in the social support group. At the end of the trial, a third of those in the dietary support group met criteria for remission of major depression, compared to 8 percent of those in the social support group.

Is a sexually transmitted yeast infection making people mentally ill? | Science | News | The Independent

“Because Candida is a natural component of the human body microbiome, yeast overgrowth or infection in the digestive tract, for example, may disrupt the gut-brain axis.  “This disruption in conjunction with an abnormally functioning immune system could collectively disturb those brain processes that are important for memory.”

Gut feeling: Research examines link between stomach bacteria, PTSD

Bienenstock and Forsythe then fed the stressed mice the same probiotics (live bacteria) found in the calm mice and examined the new fecal samples. Through magnetic resonance spectroscopy (MRS), a non-invasive analytical technique using powerful MRI technology, they also studied changes in brain chemistry. "Not only did the behavior of the mice improve dramatically with the probiotic treatment," said Bienenstock, "but it continued to get better for several weeks afterward. Also, the MRS technology enabled us to see certain chemical biomarkers in the brain when the mice were stressed and when they were taking the probiotics."

Reconceptualizing major depressive disorder as an infectious disease | Biology of Mood & Anxiety Disorders | Full Text

In the first study of this kind, germ-free (GF), specific pathogen-free (SPF), and gnotobiotic mice were compared in their response to restraint stress [36]. GF mice exhibited higher levels of plasma ACTH and corticosterone and had lower levels of brain-derived neurotrophic factor in the cortex and hippocampus, compared to SPF mice. The elevated stress response of GF mice was normalized with administration of the bacterium Bifidobacterium infantis. Another rodent study showed that administration of B. infantis in rats reduced the levels of IFN-γ, TNF-α, and IL-6 following mitogen stimulation and altered tryptophan, 5-HIAA, and DOPAC levels in the frontal cortex and amygdala [37]. Administration of the Lactobacillus rhamnosus strain in mice was shown to alter GABAergic expression in the brain: elevating GABAB1b mRNA in the cingulate and prelimbic cortices, while reducing it in hippocampus and amygdala, among other regions [38].

How Your Social Life Changes Your Microbiome

During seasons when the chimps were more sociable, their microbiomes started to converge. And the most sociable individuals, those who spent most time grooming, touching, or otherwise hanging out with their peers, had the richest diversity of species in their guts.

Round worms change immune system, reduce rejection of foreign bodies (like baby)

Infection with roundworm (Ascaris lumbricoides) is associated with earlier first births and shortened interbirth intervals, whereas infection with hookworm is associated with delayed first pregnancy and extended interbirth intervals. Thus, helminths may have important effects on human fertility that reflect physiological and immunological consequences of infection.

Single course of antibiotics can mess up the gut microbiome for a year | Ars Technica

Gut microbial diversity was significantly altered by all four kinds of antibiotics, which lasted for months. In participants that took ciprofloxacin, microbial diversity was altered for up to 12 months. The antibiotic treatments also caused a spike in genes associated with antibiotic resistance. Lastly, the researchers noted that clindamycin killed off microbes that produce butyrate, a short-chain fatty acid that inhibit inflammation, carcinogenesis, and oxidative stress in the gut.

How gut bacteria ensure a healthy brain – and could play a role in treating depression

Some gut bacteria can even alter neurotransmitter levels directly by converting glutamate – an excitatory transmitter – into GABA – an inhibitory brain chemical. And gut microbes, along with neighbouring intestinal cells, communicate with a branch of the nervous system called the enteric nervous system (ENS) whose neurons surround the entire gastrointestinal tract. This part of the nervous system is so sophisticated that many refer to it as the body’s second brain.