Enzymatic Acrolein Production System and Its Impact on Human Cells.

Acrolein is an environmental toxicant and is also generated by microbial metabolism in the intestinal tract. Aqueous acrolein rapidly dissipates from standard human cell culture media with nondetectable levels after 8 h, hindering cell-based studies to understand its biological impacts. Thus, we developed an extracellular acrolein biosynthesis system to continuously produce acrolein compatible with human cell culture conditions.

Physiologically based kinetic (PBK) modeling as a new approach methodology (NAM) for predicting systemic levels of gut microbial metabolites.

There is a clear need to develop new approach methodologies (NAMs) that combine in vitro and in silico testing to reduce and replace animal use in chemical risk assessment. Physiologically based kinetic (PBK) models are gaining popularity as NAMs in toxico/pharmacokinetics, but their coverage of complex metabolic pathways occurring in the gut are incomplete. Chemical modification of xenobiotics by the gut microbiome plays a critical role in the host response, for example, by prolonging exposure to harmful metabolites, but there is not a comprehensive approach to quantify this impact on human health.

Profiling the human intestinal environment under physiological conditions.

The spatiotemporal structure of the human microbiome, proteome and metabolome reflects and determines regional intestinal physiology and may have implications for disease. Yet, little is known about the distribution of microorganisms, their environment and their biochemical activity in the gut because of reliance on stool samples and limited access to only some regions of the gut using endoscopy in fasting or sedated individuals. To address these deficiencies, we developed an ingestible device that collects samples from multiple regions of the human intestinal tract during normal digestion.

Human metabolome variation along the upper intestinal tract.

Most processing of the human diet occurs in the small intestine. Metabolites in the small intestine originate from host secretions, plus the ingested exposome and microbial transformations. Here we probe the spatiotemporal variation of upper intestinal luminal contents during routine daily digestion in 15 healthy male and female participants.

Fluoroacetate distribution, response to fluoridation, and synthesis in juvenile Gastrolobium bilobum plants.

Like angiosperms from several other families, the leguminous shrub Gastrolobium bilobum R.Br. produces and accumulates fluoroacetate, indicating that it performs the difficult chemistry needed to make a C-F bond.

Metabolite Damage and Damage Control in a Minimal Genome.

Analysis of the genes retained in the minimized JCVI-Syn3A genome established that systems that repair or preempt metabolite damage are essential to life. Several genes known to have such functions were identified and experimentally validated, including 5-formyltetrahydrofolate cycloligase, coenzyme A (CoA) disulfide reductase, and certain hydrolases. Furthermore, we discovered that an enigmatic YqeK hydrolase domain fused to NadD has a novel proofreading function in NAD synthesis and could double as a MutT-like sanitizing enzyme for the nucleotide pool.

Spectral entropy outperforms MS/MS dot product similarity for small-molecule compound identification.

Compound identification in small-molecule research, such as untargeted metabolomics or exposome research, relies on matching tandem mass spectrometry (MS/MS) spectra against experimental or in silico mass spectral libraries. Most software programs use dot product similarity scores. Here we introduce the concept of MS/MS spectral entropy to improve scoring results in MS/MS similarity searches via library matching.

A metabolome atlas of the aging mouse brain.

The mammalian brain relies on neurochemistry to fulfill its functions. Yet, the complexity of the brain metabolome and its changes during diseases or aging remain poorly understood. Here, we generate a metabolome atlas of the aging wildtype mouse brain from 10 anatomical regions spanning from adolescence to old age.

Metabolomics analysis of time-series human small intestine lumen samples collected .

The human small intestine remains an elusive organ to study due to the difficulty of retrieving samples in a non-invasive manner. Stool samples as a surrogate do not reflect events in the upper gut intestinal tract. As proof of concept, this study investigates time-series samples collected from the upper gastrointestinal tract of a single healthy subject.

Response of metabolic and lipid synthesis gene expression changes in Camellia oleifera to mulched ecological mat under drought conditions.

Plants respond to adverse conditions by activating defense mechanisms that alter metabolism and impact agricultural crop yield. Organic mulching of Camellia oleifera leads to increased oil yield compared to control. In this study, multi-platform untargeted metabolomics and qRT-PCR were used to measure the effects of organic mulching on seed kernel metabolism.

Quantification of N-formylated lysine in bacterial protein digests using liquid chromatography/tandem mass spectrometry despite spontaneous formation and matrix effects.

Rationale: N-Formyl lysine is a well-known modification of histones and other proteins. It can also be formed as a damaged product from direct formylation of free lysine and accompanied by other lysine derivatives such as acetylated or methylated forms. In relation to the activity of cellular repair enzymes in protein turnover and to lysine metabolism, it is important to accurately quantify the overall ratio of modified lysine to free lysine.

Thioproline formation as a driver of formaldehyde toxicity in Escherichia coli.

Formaldehyde (HCHO) is a reactive carbonyl compound that formylates and cross-links proteins, DNA, and small molecules. It is of specific concern as a toxic intermediate in the design of engineered pathways involving methanol oxidation or formate reduction. The interest in engineering these pathways is not, however, matched by engineering-relevant information on precisely why HCHO is toxic or on what damage-control mechanisms cells deploy to manage HCHO toxicity.

Interaction of Gut Microbiota and High-Sodium, Low-Potassium Diet in Altering Plasma Triglyceride Profiles Revealed by Lipidomics Analysis.

Scope: High sodium and low potassium (HNaLK) intake increases the risk of cardiovascular disease (CVD) and metabolic syndrome. The authors investigate if the dietary minerals interact with the gut microbiota to alter circulating lipid profiles, implicated in CVD and metabolic syndrome.

Methods And Results: Plasma samples from Wistar rats fed a control or HNaLK diet with or without antibiotic treatment (n = 7 each, a total of 28) are subjected to lipidomics analysis.

Rethinking the PDH Bypass and GABA Shunt as Thiamin-Deficiency Workarounds.

The PDH bypass and the GABA shunt serve to maintain mainline metabolic fluxes during episodes of organellar thiamin diphosphate deficiency.

A Comprehensive Plasma Metabolomics Dataset for a Cohort of Mouse Knockouts within the International Mouse Phenotyping Consortium.

Mouse knockouts facilitate the study ofgene functions. Often, multiple abnormal phenotypes are induced when a gene is inactivated. The International Mouse Phenotyping Consortium (IMPC) has generated thousands of mouse knockouts and catalogued their phenotype data.

Salvage of the 5-deoxyribose byproduct of radical SAM enzymes.

5-Deoxyribose is formed from 5'-deoxyadenosine, a toxic byproduct of radical S-adenosylmethionine (SAM) enzymes. The degradative fate of 5-deoxyribose is unknown. Here, we define a salvage pathway for 5-deoxyribose in bacteria, consisting of phosphorylation, isomerization, and aldol cleavage steps.

Identification of a metabolic disposal route for the oncometabolite -(2-succino)cysteine in .

Cellular thiols such as cysteine spontaneously and readily react with the respiratory intermediate fumarate, resulting in the formation of stable -(2-succino)-adducts. Fumarate-mediated succination of thiols increases in certain tumors and in response to glucotoxicity associated with diabetes. Therefore, -(2-succino)-adducts such as -(2-succino)cysteine (2SC) are considered oncometabolites and biomarkers for human disease.

CoIN: co-inducible nitrate expression system for secondary metabolites in .

Background: Sequencing of fungal species has demonstrated the existence of thousands of putative secondary metabolite gene clusters, the majority of them harboring a unique set of genes thought to participate in production of distinct small molecules. Despite the ready identification of key enzymes and potential cluster genes by bioinformatics techniques in sequenced genomes, the expression and identification of fungal secondary metabolites in the native host is often hampered as the genes might not be expressed under laboratory conditions and the species might not be amenable to genetic manipulation. To overcome these restrictions, we developed an inducible expression system in the genetic model .