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Researchers alter mouse gut microbiomes by feeding good bacteria their preferred fibers -- ScienceDaily

"Fiber is understood to be beneficial. But fiber is actually a very complicated mixture of many different components," says senior author Jeffrey Gordon, a microbiologist at the Washington University School of Medicine in St. Louis. "Moreover, fibers from different plant sources that are processed in different ways during food manufacturing have different constituents. Unfortunately, we lack detailed knowledge of these differences and their biological significance. We do know that modern Western diets have low levels of fiber; this lack of fiber has been linked to loss of important members of the gut community and deleterious health effects." The researchers started by testing 34 food-grade fiber preparations, many purified from byproducts of food manufacturing such as peels from fruits and vegetables that are thrown out during production of processed foods and drinks. They used mice initially raised under sterile conditions and then colonized with human gut microbes. The animals were fed a high-fat, low-fiber diet representative of diets typically consumed in the United States, with or without different types of supplemental fibers. The goal was to identify those fibers that were best at boosting the levels of key fiber-degrading bacterial species and promoting the expression of beneficial metabolic enzymes in the microbiome.

Study may show why drugs cure brain disorders in mice but not us - STAT

Scientists have now discovered a key reason for that mouse-human disconnect, they reported on Wednesday: fundamental differences in the kinds of cells in each species’ cerebral cortex and, especially, in the activity of those cells’ key genes. In the most detailed taxonomy of the human brain to date, a team of researchers as large as a symphony orchestra sorted brain cells not by their shape and location, as scientists have done for decades, but by what genes they used. Among the key findings: Mouse and human neurons that have been considered to be the same based on such standard classification schemes can have large (tenfold or greater) differences in the expression of genes for such key brain components as neurotransmitter receptors.

Link found between gut bacteria, successful joint replacement -- ScienceDaily

In normal mice, immune system markers in the bloodstream rise during an infection, as the body responds. But in the study, these markers did not rise in mice with unhealthy microbiomes that also developed infections. The results suggest that mice with unhealthy microbiomes may have compromised immune systems.

Oxytocin could help treat alcohol use disorder -- ScienceDaily

Administering oxytocin can decrease consumption, withdrawal symptoms, and drug-seeking behavior associated with several drugs of abuse, and shows promise as a pharmacological approach to treat drug addiction. But first, researchers need to understand how oxytocin mediates these effects in animal models. To address this question, Tunstall and colleagues tested the hypothesis that oxytocin administration could normalize the maladaptive brain changes that occur in alcohol dependence and thereby reduce alcohol drinking in an established rat model of alcohol dependence. The authors investigated oxytocin's effects on dependence-induced alcohol consumption and altered signaling of the inhibitory neurotransmitter GABA in the central nucleus of the amygdala (CeA) -- a key brain region in the network affected by alcohol dependence.

High-fat diet and age alter microflora and cause inflammation in heart failure: Experiments with mice show involvement of gut bacteria and spleen in this heart pathology -- ScienceDaily

They found that the obesity-generating diet caused a sharp increase in bacteria belonging to the genus Allobaculum, phylum Firmicutes. The obesity-generating diet also increased the proportion of neutrophils in the blood of young mice. In aged mice, a similar increase in the proportion of neutrophils was found for both old mice fed a standard diet and old mice fed the obesity-generating diet. The spleen, a secondary immune organ, is a known reservoir for leukocytes that are released after heart injury. Those splenic leukocytes move to the heart to begin tissue repair and help resolve inflammation. Halade and colleagues found that the obesity-generating diet and aging led to neutrophil swarming and an altered leukocyte profile after heart attack. They also observed splenic structural deformities in these mice and a decrease in splenic CD169-positive macrophages.

Dopamine Drives Early Addiction to Heroin - Neuroscience News

To prove that increased dopamine directly causes drug reinforcement, the team looked at the effects of silencing dopamine in mice with a well-established heroin addiction and were consistently self-administering the drug using a lever. They found that when they silenced the dopamine neurons, the mice were much less likely to self-administer heroin. Crucially, when they did this early in the addiction phase, the mice were less likely to develop the habit of self-administering heroin. This showed that activation of dopamine neurons in the nucleus accumbens is required for the early positive reinforcing effects of opioid drugs.