colonization is not mediated by bile salts and utilizes Stickland fermentation of proline in an model.

Treatment with antibiotics is a major risk factor for infection, likely due to depletion of the gastrointestinal microbiota. Two microbiota-mediated mechanisms thought to limit colonization include the conversion of conjugated primary bile salts into secondary bile salts toxic to growth and competition between the microbiota and for limiting nutrients. Using a continuous flow model that simulates the nutrient conditions of the distal colon, we investigated how treatment with 6 clinically used antibiotics influenced susceptibility to infection in 12 different microbial communities cultivated from healthy individuals.

Phylogenetically diverse bacterial species produce histamine.

Histamine is an important biogenic amine known to impact a variety of patho-physiological processes ranging from allergic reactions, gut-mediated anti-inflammatory responses, and neurotransmitter activity. Histamine is found both endogenously within specialized host cells and exogenously in microbes. Exogenous histamine is produced through the decarboxylation of the amino acid L-histidine by bacterial-derived histidine decarboxylase enzymes.

Validation of atovaquone plasma levels by liquid chromatography-tandem mass spectrometry for therapeutic drug monitoring in pediatric patients.

Background: Atovaquone has traditionally been used as an antiparasitic and antifungal agent, but recent studies have shown its potential as an anticancer agent. The high variability in atovaquone bioavailability highlights the need for therapeutic drug monitoring, especially in pediatric patients. The goal of our study was to develop and validate the performance of an assay to quantify atovaquone plasma concentrations collected from pediatric cancer patients using LC-MS/MS.

Interrogation of the mammalian gut-brain axis using LC-MS/MS-based targeted metabolomics with in vitro bacterial and organoid cultures and in vivo gnotobiotic mouse models.

Interest in the communication between the gastrointestinal tract and central nervous system, known as the gut-brain axis, has prompted the development of quantitative analytical platforms to analyze microbe- and host-derived signals. This protocol enables investigations into connections between microbial colonization and intestinal and brain neurotransmitters and contains strategies for the comprehensive evaluation of metabolites in in vitro (organoids) and in vivo mouse model systems. Here we present an optimized workflow that includes procedures for preparing these gut-brain axis model systems: (stage 1) growth of microbes in defined media; (stage 2) microinjection of intestinal organoids; and (stage 3) generation of animal models including germ-free (no microbes), specific-pathogen-free (complete gut microbiota) and specific-pathogen-free re-conventionalized (germ-free mice associated with a complete gut microbiota from a specific-pathogen-free mouse), and Bifidobacterium dentium and Bacteroides ovatus mono-associated mice (germ-free mice colonized with a single gut microbe).

Serum 3-phenyllactic acid level is reduced in benign multiple sclerosis and is associated with effector B cell ratios.

Background: 3-phenyllactic acid (PLA) is produced by both intestinal bacteria and the human host. PLA exists in its D- and L- chiral forms. It modulates human immune functions, thereby acting as a mediator of bacterial-host interactions.

Insights into Microbiome and Metabolic Signatures of Children Undergoing Peanut Oral Immunotherapy.

Background: Peanut oral immunotherapy has emerged as a novel, active management approach for peanut-allergic sufferers, but limited data exist currently on the role of the microbiome in successful desensitization.

Objective: We examined the oral and gut microbiome in a cohort of 17 children undergoing peanut oral immunotherapy with the aim to identify the microbiome signatures associated with successful desensitization. We also set out to characterize their fecal metabolic profiles after successful therapy.

Unraveling the Metabolic Requirements of the Gut Commensal .

Bacteroidetes are the most common bacterial phylum in the mammalian intestine and the effects of several spp. on multiple facets of host physiology have been previously described. Of the spp.

Neurotransmitter Profiles Are Altered in the Gut and Brain of Mice Mono-Associated with .

Background: Accumulating evidence indicates that the gut microbiota can synthesize neurotransmitters as well as impact host-derived neurotransmitter levels. In the past, it has been challenging to decipher which microbes influence neurotransmitters due to the complexity of the gut microbiota.

Methods: To address whether a single microbe, could regulate important neurotransmitters, we examined genomes and explored neurotransmitter pathways in secreted cell-free supernatant using LC-MS/MS.

The metabolic profile of Bifidobacterium dentium reflects its status as a human gut commensal.

Background: Bifidobacteria are commensal microbes of the mammalian gastrointestinal tract. In this study, we aimed to identify the intestinal colonization mechanisms and key metabolic pathways implemented by Bifidobacterium dentium.

Results: B.

-derived y-glutamylcysteine suppresses ER-mediated goblet cell stress and reduces TNBS-driven colonic inflammation.

Endoplasmic reticulum (ER) stress compromises the secretion of MUC2 from goblet cells and has been linked with inflammatory bowel disease (IBD). Although can beneficially modulate mucin production, little work has been done investigating the effects of on goblet cell ER stress. We hypothesized that secreted factors from downregulate ER stress genes and modulates the unfolded protein response (UPR) to promote MUC2 secretion.

Assessment of the gut bacterial microbiome and metabolome of girls and women with Rett Syndrome.

Background: Gastrointestinal problems affect the health and quality of life of individuals with Rett syndrome (RTT) and pose a medical hardship for their caregivers. We hypothesized that the variability in the RTT phenotype contributes to the dysbiosis of the gut microbiome and metabolome in RTT, predisposing these individuals to gastrointestinal dysfunction.

Objectives: We characterized the gut bacterial microbiome and metabolome in girls and young women with RTT (n = 44) and unaffected controls (n = 21), and examined the relation between the composition of the microbiome and variations in the RTT phenotype.

Ruggedness testing of liquid chromatography-tandem mass spectrometry system components using microbiome-relevant methods and matrices.

Recently, an opportunity to perform a broad ruggedness assessment of our liquid chromatography-tandem mass spectrometry (LC-MS/MS) system presented itself during the analytical planning phase of a large-scale human fecal microbiome study. The specific aim of this project was to study the microbial-mediated metabolism of a targeted set of bile acids/salts by mixed bacterial communities cultured from the feces of 12 healthy volunteers when grown in a custom growth medium and following exposure to different clinically-relevant antibiotics. The magnitude of this study offered a rare opportunity to significantly stress procedures and LC-MS/MS system components comprised in our bile acid/salt targeted metabolomics method.

A high-throughput LC-MS/MS method for the measurement of the bile acid/salt content in microbiome-derived sample sets.

Due to the physicochemical properties of bile acids/salts (., hydrophobic and ionizable), the application of reverse-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based methods are ideally suited for the measurement of these compounds in a host of microbiologically-relevant matrices. Here, we provide a detailed bioanalytical protocol that contains several modifications of a method previously described by Wegner et al.

Sterilization performance comparison between an autosampler-ready microporous filter vial and a syringe-based filter.

Herein we report that the Thomson Standard and eXtreme/FV® filter vials (0.2 μm polyvinylidene difluoride filter membrane) are as effective as gold standard microporous membrane-based syringe filters at removing bacteria, such as Klebsiella pneumonia, from media samples produced in the microbiological laboratory.

Gut Microbe-Mediated Suppression of Inflammation-Associated Colon Carcinogenesis by Luminal Histamine Production.

Microbiome-mediated suppression of carcinogenesis may open new avenues for identification of therapeutic targets and prevention strategies in oncology. Histidine decarboxylase (HDC) deficiency has been shown to promote inflammation-associated colorectal cancer by accumulation of CD11bGr-1 immature myeloid cells, indicating a potential antitumorigenic effect of histamine. Here, we demonstrate that administration of hdcLactobacillus reuteri in the gut resulted in luminal hdc gene expression and histamine production in the intestines of Hdc mice.

Nuclear Perilipin 5 integrates lipid droplet lipolysis with PGC-1α/SIRT1-dependent transcriptional regulation of mitochondrial function.

Dysfunctional cellular lipid metabolism contributes to common chronic human diseases, including type 2 diabetes, obesity, fatty liver disease and diabetic cardiomyopathy. How cells balance lipid storage and mitochondrial oxidative capacity is poorly understood. Here we identify the lipid droplet protein Perilipin 5 as a catecholamine-triggered interaction partner of PGC-1α.