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Objective Alzheimer’s disease (AD) is a global health problem without effective methods to alleviate the disease progression. Amyloid β-protein (Aβ) is widely accepted as a key biomarker for AD. Metabolic syndromes, including obesity and insulin resistance, are key high risk factors for AD. Akkermansia muciniphila (Akk), the only representative human gut microbe in the genus Verrucomicrobia, can prevent the weight gain caused by a high-fat diet, repair the damaged integrity of the intestinal epithelium barrier, reduce endotoxin levels in blood and improve insulin resistance. The aim of this study is to explore the impact of Akk administration in AD model mice in different diets. Methods APP/PS1 mice were fed either a normal chow diet or a high-fat diet and were treated with Akk by gavage each day for 6 months. The impacts of Akk on glucose metabolism, intestinal barrier and lipid metabolism in the mouse model of AD were determined. Changes in brain pathology and neuroethology were also analyzed. Results Akk effectively reduced the fasting blood glucose and serum diamine oxidase levels, and alleviated the reduction of colonic mucus cells in APP/PS1 mice. After treatment with Akk, the APP/PS1 mice showed obviously reduced blood lipid levels, improved hepatic steatosis and scapular brown fat whitening. Moreover, Akk promoted the reduction of Aβ 40–42 levels in the cerebral cortex of APP/PS1 mice, shortened the study time and improved the completion rate in Y-maze tests. Conclusion Akk effectively improved glucose tolerance, intestine barrier dysfunction and dyslipidemia in AD model mice. Our study results suggested that Akk could delay the pathological changes in the brain and relieve impairment of spatial learning and memory in AD model mice, which provides a new strategy for prevention and treatment of AD., APP/PS1 mice display alterations in physiological processes after treated with Akk. It is showed that the damaged integrity of the intestinal epithelium barrier is repaired, leading to obviously reduced blood glucose and lipid levels, improved hepatic steatosis, insulin resistance and scapular brown fat whitening, which are beneficial to reduce Aβ 40–42 levels in the brain of APP/PS1 mice.

Phascolarctobacterium can produce short-chain fatty acids, including acetate and propionate, and can be associated with the metabolic state and mood of the host. The present study investigated the colonization characteristics of Phascolarctobacterium faecium in healthy individuals 1 year old). The permillage of Phascolarctobacterium faecium in total bacteria ranged between 0.004–1.479. There was presence of Phascolarctobacterium faecium-like bacteria in younger individuals with a gradual increase in the number of bacteria maintained at a high level with increasing ages (between 1 and 60 years old), but with a decrease in elderly individuals (>60 years old). The results of the present study demonstrated that Phascolarctobacterium faecium is abundantly colonized in the human gastrointestinal tract.

Background The study aimed to investigate the differences of different Akkermansia muciniphila (A.muciniphila) genotypes on metabolic protective effects in mice with high-fat diet and explore possible mechanisms. Methods Male C57BL/6 mice were randomly divided into 6 groups, including high-fat diet (HFD)+ A.muciniphila I/II/PBS group, normal chow diet (NCD)+A.muciniphila I/ II /PBS group, respectively. Dietary intervention and A.muciniphila gavage were performed simultaneously. Blood glucose and lipid metabolism, brown adipose morphology and activities, and intestinal barrier function were examined after the mice were sacrificed. Results A.muciniphila gavage improved the impaired glucose tolerance, hyperlipidemia and liver steatosis in HFD mice, and that A.muciniphila II was not as effective as A.muciniphila I. This phenomenon might be because A.muciniphila I intervention significantly inhibited brown adipose tissue whitening and inflammation induced by HFD, by repairing the intestinal barrier and relieving endotoxemia. A.muciniphila II did not display the same results as A.muciniphila I in HFD mice, but had stronger effects in the NCD mice. Conclusions This study mainly reveals the distinct functions of different A.muciniphila genotypes on diet-induced obesity, suggesting that different A.muciniphila genotypes may play inequitable roles in pathological conditions through distinct action pathways.

The prevalence of obesity and diabetes, and their complicating mental disorders, severely affect public health. This study aimed to investigate the long-term effects of an Akkermansia muciniphila subtype (A. muciniphilasub) on high-fat diet-induced obesity and diabetes, and to evaluate whether this subtype can alleviate their complicated mental disorders. Whole genome sequencing and short chain fatty acid production analysis in supernatant of pure culture were performed. Female adult C57BL/6 mice were fed a high-fat diet or a normal chow diet and were gavaged with A. muciniphilasub or phosphate-buffered saline daily for 10 months. Body weight, food consumption and blood glucose were measured. At the end of the treatment period, all mice were subjected to the Y-maze test, sucrose preference test, analyses of serum, fecal microbiota analysis and histological examination. This A. muciniphilasub had 278 unique genes compared to the type strain (A. muciniphila ATCC BAA-835) and produced short chain fatty acids both. A. muciniphilasub administration significantly reduced body weight gain and improved the spatial memory of high-fat diet-fed mice. A. muciniphilasub increased Nissl bodies in neurons of the hippocampus, and restored the high-fat diet-inhibited tryptophan metabolism. The high-fat diet led to decreased serum 5-hydroxytryptamine and induced depression, which were not alleviated by A. muciniphilasub. A. muciniphilasub increased the relative fecal abundance of Bifidobacterium, and was negatively correlated with the fecal abundance of Bacteroides. The present study demonstrated the beneficial effects of this A. muciniphilasub on body weight, blood glucose control and the alleviation of the memory decay caused by a high-fat diet in mice.

Aim This study investigates the colonization rate of Akkermansia muciniphila in the gastrointestinal tracts of people living in southern China and applies a modified method for the isolation and subtyping of A. muciniphila strains from faecal samples. Methods and Results Fresh faecal samples were collected and bacterial DNA was extracted from these samples for real-time PCR analysis. Strains were separated using a culture-dependent sPCR-directed method and classified using an enterobacterial repetitive intergenic consensus (ERIC-PCR) DNA fingerprinting method. The colonization rate for the sample population from southern China was 51·74%. We isolated 22 strains from human faeces. The results revealed that all strains were identifiable as A. muciniphila with 99–100% identity to the type-strain ATCC BAA-835. ERIC-PCR resulted in grouping of the DNA fingerprints showed that 12 distinct clusters were distinguished with a delineation level of 100%. Conclusions Southern China has a high rate of A. muciniphila colonization and over 12 different subtype strains reside in faecal samples. Significance and Impact of the Study Akkermansia muciniphila has a beneficial role in human gastrointestinal tract. These studies provide a better understanding of A. muciniphila and details of its colonization in the human gastrointestinal tract.

Using high-hydrogen fuels in industrial gas turbines is an effective way to achieve near-zero carbon emission power generation. Lean premixed combustion can effectively reduce NOx emission. However, due to the strong flashback and auto-ignition tendencies during fuel-air mixing, it is a challenge to use lean premix combustion mode of high hydrogen fuels under gas turbine operation conditions. An innovative conceptual design of arrayed-vanes premixer was proposed to achieve safe and uniform mixing of fuel and air. Inside the arrayed-vanes premixer, a cascade of mixing vanes is arranged in the axial annular air flow passage. Fuel-air mixing and flow field stretch are improved and well controlled by the arrayed vanes. The conditions of auto-ignition and flame stabilization inside the vanes are unsatisfied. Meanwhile the upstream flow disturbance will be inhibited by the arrayed vanes, which benefits combustion stability. The arrayed-vanes premixer was designed and its flow field was numerically simulated under the operation condition of F class gas turbine combustors. The flow and fuel-air mixing behavior was analyzed and compared with a typical swirl-based premixer now widely used in DLN combustors of F class gas turbines. The results show that the non-uniformity index of fuel concentration distribution at the exit plane of the arrayed-vanes premixer is 50% lower than that of the swirl-based premixer. The responses of flow field at the exit plane to the inlet flow disturbance was calculated and compared for the two types of permixer. The inlet flow disturbance includes the velocity distortion and the oscillation of the pressure. The results show that the arrayed-vanes premixer absorbs and damps the inlet flow disturbance better than the swirl-based premixer. And it exhibits highly monochromatic characteristic through the acoustic signature analysis. Furthermore, the tendencies of auto-ignition and flashback were investigated by examining the flow field and the flammability of hydrogen. The results show that there is a low risk of auto-ignition or flashback due to the short residence time and the high discharge velocity. The present study indicates that the arrayed-vanes premixer achieves ultra uniform fuel-air mixing, good adaptability to inlet flow disturbance and anti auto-ignition and flash back, which is benefit to DLN combustor designed for high-hydrogen fuels. This design will be possibly used in DLN combustors after future developments.