Specific Metabolites Research Articles

Light and temperature culture conditions impact the metabolome of the cyanobacterium of therapeutic interest Planktothricoides raciborskii PMC 877.14

Cyanobacteria are ancient photosynthetic microorganisms with a long evolutionary history that have adapted to inhabit diverse environments, such as thermal waters and muds. To do so, they are known to produce a wide range of bioactive molecules likely involved in adaptative traits such as high light and/or high temperature resistance mechanisms, which makes them particularly interesting for inclusion in thermal treatments and various therapeutic applications.In this study, the impact of higher temperature and light intensity culture conditions on the metabolome of a promising cyanobacterial strain isolated from the muds of the Balaruc-les-Bains thermal station, Planktothricoides raciborskii PMC 877.14, was investigated through liquid chromatography and mass spectrometry analyses. Statistical analyses of the biological data and molecular network construction allowed for the exploration of potential metabolite induction under different culture conditions, in order to drive the production of specific metabolites aimed at coping with cellular stress. A global shift on intracellular metabolic composition was observed over time with increased biomass production. Higher light intensity was found to stimulate both growth and production of antioxidant and/or photoprotective molecules (such as ergothioneine, mycosporine-like amino acids or carotenoids) while an increase in temperature influenced the higher production of phycobilins (such as phycoerythrin and phycocyanin).These results highlight the importance of culture/environmental conditions in driving intracellular metabolite differentiation and open up new perspectives in selecting of the optimal parameters for the growth and production of bioactive molecules for therapeutic applications in the cyanobacterium P. raciborskii PMC 877.14.

Metabolomic analysis reveals potential role of immunometabolism dysregulation in recurrent pregnancy loss.

Recurrent pregnancy loss (RPL) affects women's reproductive health seriously, with immune dysfunction playing a key role in its cause, yet the exact mechanisms remain elusive. We aim to investigate potential mechanisms and identify biomarkers linked to RPL. Immune cytokine testing and metabolomic profiling were conducted on the serum of 34 RPL patients and 30 healthy individuals. The metabolic pathways of the differential metabolites were analyzed, and specific metabolites were validated through targeted profiling. Potential biomarkers were identified, and the relationships between immune cytokines and differential metabolites were explored. In the RPL group, serum interleukin-6 and interleukin-10 levels were significantly higher, while interleukin-2 and interferon-γ were significantly lower. A total of 296 differential metabolites were detected by untargeted metabolomic profiling between the RPL and control groups, with most linked to amino acid metabolism. Targeted metabolomic profiling of amino acid metabolism revealed upregulation of indole-3-acetic acid, tyrosine, glycine, isoleucine, tryptophan, lysine, aspartic acid, arginine, leucine, threonine, glutamic acid, cystine, and phenylpyruvic acid (PPA) in the RPL group. Moreover, PPA and 5-hydroxy-L-tryptophan showed great potential in predicting RPL in a diagnostic model. Cystine and tyrosine were associated with immune cytokines in correlation analysis. The study highlights the role of amino acid metabolism in RPL pathogenesis, suggesting that PPA and 5-HTP may be potential predictive indicators, while cystine and tyrosine may potentially regulate immune responses related to RPL. Further investigation into the molecular mechanisms underlying these findings could potentially result in the creation of novel diagnostic and therapeutic approaches for RPL.

T2T genome assemblies of Fallopia multiflora (Heshouwu) and F. multiflora var. angulata

The traditional Chinese medicinal plant Fallopia multiflora (hereafter AYY) is well known for its anti-hyperlipidaemia, immunomodulating, and hepatoprotective effects, attributed to its abundance of anthraquinones and stilbene glycosides, which are distinct to its variety F. multiflora var. angulata (hereafter CYY) in proportion and composition. In this study, telomere-to-telomere (T2T) genomes were assembled for AYY and CYY using PacBio HiFi reads and Hi-C data. The genome sizes, percentages of repetitive sequences, and numbers of protein-coding genes of AYY and CYY assemblies were 1,458.37 Mb/70.48%/84,768 and 1,174.38 Mb/67.36%/69,100, respectively. Comprehensive assessments confirmed high continuity (contig N50: 112.58 Mb and 94.83 Mb; number of gaps: 9 and 5), completeness (BUSCOs: 97.30% and 97.60%; LAI: 16.93 and 16.77), and correctness (QV: 51.42 and 52.60) of AYY and CYY assemblies. These T2T genomes of F. multiflora provide valuable resources for studying the biosynthesis of specialized metabolites and facilitating precise genetic improvement.

Branched-chain amino acids modulate the proteomic profile of Trypanosoma cruzi metacyclogenesis induced by proline.

Trypanosoma cruzi, the causative agent of Chagas disease, has a complex life cycle that involves triatomine insects as vectors and mammals as hosts. The differentiation of epimastigote forms into metacyclic trypomastigotes within the insect vector is crucial for the parasite's life cycle progression. Factors influencing this process, including temperature, pH, and nutritional stress, along with specific metabolite availability, play a pivotal role. Amino acids like proline, histidine, and glutamine support cell differentiation, while branched-chain amino acids (BCAAs) inhibit it. Interestingly, combining the pro-metacyclogenic amino acid proline with one of the anti-metacyclogenic BCAAs results in viable metacyclics with significantly reduced infectivity. To explore the characteristics of metacyclic parasites differentiated in the presence of BCAAs, proteomics analyses were conducted. Metacyclics obtained in triatomine artificial urine (TAU) supplemented with proline alone and in combination with leucine, isoleucine, or valine were compared. The analyses revealed differential regulation of 40 proteins in TAU-Pro-Leu, 131 in TAU-Pro-Ile, and 179 in TAU-Pro-Val, as compared to metacyclics from TAU-Pro. Among these, 22%, 11%, and 13% of the proteins were associated with metabolic processes, respectively. Notably, enzymes related to glycolysis and the tricarboxylic acid (TCA) cycle were reduced in metacyclics with Pro-BCAAs, while enzymes involved in amino acid and purine metabolic pathways were increased. Furthermore, metacyclics with Pro-Ile and Pro-Val exhibited elevated enzymes linked to lipid and redox metabolism. The results revealed five proteins that were increased and four that were decreased in common in the presence of Pro+BCAAs, indicating their possible participation in key processes related to metacyclogenesis. These findings suggest that the presence of BCAAs can reshape the metabolism of metacyclics, contributing to the observed reduction in infectivity in these parasites.

Nanoformulated fenbendazole as an attractive approach for treating neurocysticercosis: in vitro and in vivo studies

Purpose This work aimed to develop fenbendazole nanocrystals to evaluate their effects on the energetic metabolism of Taenia crassiceps cysticerci, following an intracranial inoculation in mice. Methods Fenbendazole was nanoformulated by the antisolvent method using poloxamers 188 and 407 as stabilizers. The nanosuspensions were lyophilized without cryoprotectants and the nanocrystals were characterized in terms of particle size, zeta potential, and dissolution performance. The in vivo study was performed in infected animals treated with nanoformulated fenbendazole and raw drug and their metabolic impact was quantified by analyzing specific metabolites. Results Fenbendazole samples were obtained by nanoprecipitation in > 80% yield. The average particle size of the freeze-dried samples was between 372 nm and 1600 nm. The nanosystems released a greater amount of the drug into the solution, compared to the raw drug. The in vivo studies showed that the fenbendazole-treated groups induced gluconeogenesis, partial blockage of the TCA cycle, and increased protein catabolism. As seen, the nanoformulation presented a greater effect on these parameters than the raw drug leading to remarkable modifications in the metabolism of the parasite, which in turn can influence the overall course of the infection and treatment outcomes. Conclusion These findings suggest that nanoformulated fenbendazole may be considered a valuable approach for an effective treatment of neurocysticercosis.

Perturbations in the blood metabolome up to a decade before prostate cancer diagnosis in 4387 matched case-control sets from the European Prospective Investigation into Cancer and Nutrition.

Measuring pre-diagnostic blood metabolites may help identify novel risk factors for prostate cancer. Using data from 4387 matched case-control pairs from the European Prospective Investigation into Cancer and Nutrition (EPIC) study, we investigated the associations of 148 individual metabolites and three previously defined metabolite patterns with prostate cancer risk. Metabolites were measured by liquid chromatography-mass spectrometry. Multivariable-adjusted conditional logistic regression was used to estimate the odds ratio per standard deviation increase in log metabolite concentration and metabolite patterns (OR1SD) for prostate cancer overall, and for advanced, high-grade, aggressive. We corrected for multiple testing using the Benjamini-Hochberg method. Overall, there were no associations between specific metabolites or metabolite patterns and overall, aggressive, or high-grade prostate cancer that passed the multiple testing threshold (padj <0.05). Six phosphatidylcholines (PCs) were inversely associated with advanced prostate cancer diagnosed at or within 10 years of blood collection. metabolite patterns 1 (64 PCs and three hydroxysphingomyelins) and 2 (two acylcarnitines, glutamate, ornithine, and taurine) were also inversely associated with advanced prostate cancer; when stratified by follow-up time, these associations were observed for diagnoses at or within 10 years of recruitment (OR1SD 0.80, 95% CI 0.66-0.96 and 0.76, 0.59-0.97, respectively) but were weaker after longer follow-up (0.95, 0.82-1.10 and 0.85, 0.67-1.06). Pattern 3 (8 lyso PCs) was associated with prostate cancer death (0.82, 0.68-0.98). Our results suggest that the plasma metabolite profile changes in response to the presence of prostate cancer up to a decade before detection of advanced-stage disease.

Adaptive laboratory evolution of Lipomyces starkeyi for high production of lignin derivative alcohol and lipids with comparative untargeted metabolomics-based analysis.

Adaptive laboratory evolution (ALE) is an impactful technique for cultivating microorganisms to adapt to specific environmental circumstances or substrates through iterative growth and selection. This study utilized an adaptive laboratory evolution method on Lipomyces starkeyi for high tolerance in producing lignin derivative alcohols and lipids from syringaldehyde. Afterward, untargeted metabolomics analysis was employed to find the key metabolites that play important roles in the better performance of evolved strains compared to the wild type. Lignin, a prominent constituent of plant biomass, is a favorable source material for the manufacture of biofuel and lipids. Nevertheless, the effective transformation of chemicals produced from lignin into products with high economic worth continues to be a difficult task. In this study, we exposed L. starkeyi to a series of flask passaging experiments while applying selective pressure to facilitate its adaptation to syringaldehyde, a specific type of lignin monomeric aldehyde. Using ALE, we successfully developed a new strain, DALE-22, which can synthesize syringyl alcohol up to 18.74 mM from 22.28 mM syringaldehyde with 41.9% lipid accumulation. In addition, a comprehensive examination of untargeted metabolomics identified six specific crucial metabolites linked to the improved tolerance of the evolved strain in the utilization of syringaldehyde, including 2-aminobutyric acid, allantoin, 4-hydroxyphenethyl alcohol, 2-aminoethanol, tryptophan, and 5-aminovaleric acid. The results of our study reveal how L. starkeyi adapts to using substrates produced from lignin. These findings offer important information for developing strategies to improve the process of converting lignin into valuable products for sustainable biorefinery applications.

The biology and chemistry of a mutualism between a soil bacterium and a mycorrhizal fungus

Arbuscular mycorrhizal (AM) fungi (e.g., Rhizophagus species) recruit specific bacterial species in their hyphosphere. However, the chemical interplay and the mutual benefit of this intricate partnership have not been investigated yet, especially as it involves bacteria known as strong producers of antifungal compounds such as Bacillus velezensis. Here, we show that the soil-dwelling B.velezensis migrates along the hyphal network of the AM fungus R.irregularis, forming biofilms and inducing cytoplasmic flow in the AM fungus that contributes to host plant root colonization by the bacterium. During hyphosphere colonization, R.irregularis modulates the biosynthesis of specialized metabolites in B.velezensis to ensure stable coexistence and as a mechanism to ward off mycoparasitic fungi and bacteria. These mutual benefits are extended into a tripartite context via the provision of enhanced protection to the host plant through the induction of systemic resistance.

Comparative genomics unravels a rich set of biosynthetic gene clusters with distinct evolutionary trajectories across fungal species (Termitomyces) farmed by termites

The use of compounds produced by hosts or symbionts for defence against antagonists has been identified in many organisms, including in fungus-farming termites (Macrotermitinae). The obligate mutualistic fungus Termitomyces plays a pivotal role in plant biomass decomposition and as the primary food source for these termites. Despite the isolation of various specialized metabolites from different Termitomyces species, our grasp of their natural product repertoire remains incomplete. To address this knowledge gap, we conducted a comprehensive analysis of 39 Termitomyces genomes, representing 21 species associated with members of five termite host genera. We identified 754 biosynthetic gene clusters (BGCs) coding for specialized metabolites and categorized 660 BGCs into 61 biosynthetic gene cluster families (GCFs) spanning five compound classes. Seven GCFs were shared by all 21 Termitomyces species and 21 GCFs were present in all genomes of subsets of species. Evolutionary constraint analyses on the 25 most abundant GCFs revealed distinctive evolutionary histories, signifying that millions of years of termite-fungus symbiosis have influenced diverse biosynthetic pathways. This study unveils a wealth of non-random and largely undiscovered chemical potential within Termitomyces and contributes to our understanding of the intricate evolutionary trajectories of biosynthetic gene clusters in the context of long-standing symbiosis.

12440 Exploring The Potential Protective Role Of The Bacterial-derived Metabolite Indole-3-propionic Acid Against Obesogenic Insults In Placenta Cell Lines

Abstract Disclosure: J. Ernst: None. L. Conlon: None. R. Gupta: None. L. Kang: None. M.E. Heard-Lipsmeyer: None. Obesity during pregnancy is associated with detrimental changes in placental function that lead to the development of complications such as gestational diabetes and preeclampsia as well as altered metabolism in the offspring. With the incidence of obesity reaching epidemic levels world-wide, it is imperative to find mechanisms to mitigate these risks during pregnancy. The gut-microbiome is a diverse system that regulates numerous body functions through the secretion of specific metabolites. Gut dysbiosis has recently emerged as one mechanism that contributes to placental dysfunction and clear associations between obesity and gut dysbiosis are evident. Indole-3-propionic acid (IPA) is a gut microbiome-derived metabolite that has anti-inflammatory, anti-oxidative stress and glucose regulatory functions, all of which are dysregulated in obesity. Previous studies have found diminished levels of IPA in serum of women with overweight/obesity. However, it remains unknown what the physiological functions of IPA are in the placenta and if it could have potential protective effects against perturbations caused by obesity. The objective of this study is to determine what physiological role IPA plays in the placenta and if IPA can protect against obesogenic insults that contribute to placental pathology. For this study, we developed an in vitro model of obesity where two human placental cell lines, BeWo (choriocarcinoma) and HTR8 (normal immortalized trophoblasts) were cultured in media conditioned by mature human adipocytes (ACM). RNA sequencing (RNAseq) analysis was used to determine acute effects of IPA treatment after 24 hours in the presence and absence of ACM. We further examined the influence of IPA on insulin signaling with physiological and hyperinsulinemia levels of insulin at 24 and 72 hours utilizing QPCR and western blot analyses. RNAseq analysis revealed treatment with physiological levels of IPA induced changes in genes associated with normal placental function, autophagy and inflammatory mediated processes and other pathways. Our RNAseq analysis offers initial insight into the molecular mechanisms of IPA in placental cells. Future analyses will investigate the potential role of insulin signaling, glucose homeostasis and oxidative stress. Collectively, this study highlights the importance of a healthy gut microbiome and potentially serves as a window of opportunity to mitigate the onset or severity of pregnancy-related disorders such as gestational diabetes by enhancing the gut microbiome prior to pregnancy. Presentation: 6/1/2024

12440 Exploring The Potential Protective Role Of The Bacterial-derived Metabolite Indole-3-propionic Acid Against Obesogenic Insults In Placenta Cell Lines

Abstract Disclosure: J. Ernst: None. L. Conlon: None. R. Gupta: None. L. Kang: None. M.E. Heard-Lipsmeyer: None. Obesity during pregnancy is associated with detrimental changes in placental function that lead to the development of complications such as gestational diabetes and preeclampsia as well as altered metabolism in the offspring. With the incidence of obesity reaching epidemic levels world-wide, it is imperative to find mechanisms to mitigate these risks during pregnancy. The gut-microbiome is a diverse system that regulates numerous body functions through the secretion of specific metabolites. Gut dysbiosis has recently emerged as one mechanism that contributes to placental dysfunction and clear associations between obesity and gut dysbiosis are evident. Indole-3-propionic acid (IPA) is a gut microbiome-derived metabolite that has anti-inflammatory, anti-oxidative stress and glucose regulatory functions, all of which are dysregulated in obesity. Previous studies have found diminished levels of IPA in serum of women with overweight/obesity. However, it remains unknown what the physiological functions of IPA are in the placenta and if it could have potential protective effects against perturbations caused by obesity. The objective of this study is to determine what physiological role IPA plays in the placenta and if IPA can protect against obesogenic insults that contribute to placental pathology. For this study, we developed an in vitro model of obesity where two human placental cell lines, BeWo (choriocarcinoma) and HTR8 (normal immortalized trophoblasts) were cultured in media conditioned by mature human adipocytes (ACM). RNA sequencing (RNAseq) analysis was used to determine acute effects of IPA treatment after 24 hours in the presence and absence of ACM. We further examined the influence of IPA on insulin signaling with physiological and hyperinsulinemia levels of insulin at 24 and 72 hours utilizing QPCR and western blot analyses. RNAseq analysis revealed treatment with physiological levels of IPA induced changes in genes associated with normal placental function, autophagy and inflammatory mediated processes and other pathways. Our RNAseq analysis offers initial insight into the molecular mechanisms of IPA in placental cells. Future analyses will investigate the potential role of insulin signaling, glucose homeostasis and oxidative stress. Collectively, this study highlights the importance of a healthy gut microbiome and potentially serves as a window of opportunity to mitigate the onset or severity of pregnancy-related disorders such as gestational diabetes by enhancing the gut microbiome prior to pregnancy. Presentation: 6/1/2024

Causal effects of plasma metabolites on autoimmune hepatitis (AIH): a bidirectional two-sample mendelian randomization study

Autoimmune hepatitis(AIH) is a chronic progressive inflammatory liver disease induced by loss of immune tolerance. The role of circulating metabolites in disease pathogenesis is unclear. This study aimed to investigate potential causal links between plasma metabolites and AIH risk by employing a two-sample Mendelian randomization approach. A comprehensive bidirectional two-sample Mendelian randomization analysis was conducted using genome-wide significant variant-metabolite and variant-AIH associations in European ancestry individuals. Various methods assessed causal relationships among 1400 metabolites and AIH, incorporating sensitivity analyses to evaluate pleiotropy and heterogeneity. Fifty-eight metabolites displayed possible associations, including increased AIH risk with genetically predicted higher kynurenine (p = 2.79 × 10− 5, OR: 1.64, 95% CI 1.30–2.07) and a protective effect for the dopamine sulfate ratio (p = 1.06 × 10− 5,OR: 0.62, 95% CI 0.49–0.79). Reciprocal analysis revealed a causal effect of AIH on kynurenine( p = 2.79 × 10− 5, OR: 1.64, 95% CI 1.30–2.07), but not on the dopamine sulfate ratio(p = 0.691, OR: 1.05, 95% CI 0.67–1.64). Our genetics-based approach provides evidence supporting a causal role for specific metabolite levels in AIH risk. The results deliver evidence supporting a causal effect of a specific metabolite ratio(dopamine 4-sulfate/dopamine 3-O-sulfate) on AIH risk. Experimental validation and mechanistic examinations are warranted to confirm findings.

Phospholipids, Sphingolipids, and Cholesterol-Derived Lipid Mediators and Their Role in Neurological Disorders.

Neural membranes are composed of phospholipids, sphingolipids, cholesterol, and proteins. In response to cell stimulation or injury, the metabolism of lipids generates various lipid mediators, which perform many cellular functions. Thus, phospholipids release arachidonic acid or docosahexaenoic acid from the sn-2 position of the glycerol moiety by the action of phospholipases A2. Arachidonic acid is a precursor for prostaglandins, leukotrienes, thromboxane, and lipoxins. Among these mediators, prostaglandins, leukotrienes, and thromboxane produce neuroinflammation. In contrast, lipoxins produce anti-inflammatory and pro-resolving effects. Prostaglandins, leukotrienes, and thromboxane are also involved in cell proliferation, differentiation, blood clotting, and blood vessel permeability. In contrast, DHA-derived lipid mediators are called specialized pro-resolving lipid metabolites (SPMs). They include resolvins, protectins, and maresins. These mediators regulate immune function by producing anti-inflammatory, pro-resolving, and cell protective effects. Sphingolipid-derived metabolites are ceramide, ceramide1-phosphate, sphingosine, and sphingosine 1 phosphate. They regulate many cellular processes, including enzyme activities, cell migration and adhesion, inflammation, and immunity. Cholesterol is metabolized into hydroxycholesterols and 7-ketocholesterol, which not only disrupts membrane fluidity, but also promotes inflammation, oxidative stress, and apoptosis. These processes lead to cellular damage.

Illuminating Cannabis sativa L.: The Power of Light in Enhancing C. sativa Growth and Secondary Metabolite Production.

Light is crucial for higher plants, driving photosynthesis and serving as a powerful sensory signal that profoundly modulates growth, development, physiological functions, hormone activation, and biochemical pathways. Various light parameters-quality, intensity, composition, and photoperiod-exert a tremendous influence on plant growth and development, particularly in industrial hemp (Cannabis sativa L.). C. sativa, a crop of historical significance and unparalleled versatility, holds immense value in the food, fiber, and medicinal industries. The cultivation of medicinal cannabis is burgeoning in controlled environments due to evolving healthcare regulations. Optimal light conditions significantly enhance both yield and harvest quality, notably increasing the density of apical inflorescences and the ratio of inflorescence to total aboveground biomass. C. sativa metabolites, especially phenolic and terpene compounds and Phytocannabinoids like CBD (cannabidiol), THC (tetrahydrocannabinol), and CBG (cannabigerol), possess immense medicinal value. Secondary metabolites in C. sativa predominantly accumulate in the trichomes of female flowers and surrounding sugar leaves, underscoring the critical need to boost inflorescence weight and metabolite concentrations while ensuring product consistency. Different light parameters distinctly impact C. sativa's metabolic profile, providing a robust foundation for understanding the optimal conditions for synthesizing specific secondary metabolites. While the effects of light measurement on various crops are well-established, scientific evidence specifically relating to light quality effects on C. sativa morphology and secondary metabolite accumulation remains scarce. In this review, we critically summarized how different light properties can alter cannabis growth (vegetative and reproductive), physiology and metabolism. Furthermore, the mechanisms by which specific wavelengths influence growth, development, and secondary metabolite biosynthesis in C. sativa are not fully elucidated, which could be a prospective task for future researchers. Our review paves the way for a profound understanding of light's influence on C. sativa growth and advancements in greenhouse settings to maximize metabolite production for commercial use.

Effects of supplemental medusa (Rhopilema esculentum) on intestinal microbiota and metabolites in silver pomfret (Pampus argenteus).

Pampus argenteus demonstrates a preference for Rhopilema esculentum as prey, yet the ramifications of consuming supplemental medusa on fish microbiota and metabolism remain elusive. To elucidate these effects, 300 juvenile fish were divided into two groups: control group (C, given commercial food only) and supplemental medusa (SM) group (given supplemental medusa + commercial feed). After 15 days, fish in the SM group exhibited a significant increase in fatness, the amylase activity in the intestine significantly increased, and the intestinal microvilli were arranged more neatly. The comprehensive approach involving 16S rRNA amplicon sequencing and metabolomics was employed, leading to the identification of five genera within the SM group, namely Lactococcus, Cohaesibacter, Maritalea, Sulfitobacter, and Carnobacterium. Functional prediction analysis of the microbiota indicated that the consumption of supplemental medusa facilitated processes such as glycolysis/gluconeogenesis and amino acid absorption. Metabolomics analysis revealed significant enrichment of 85 differential metabolites, most of them belonging to fatty acids and conjugates. These differential metabolites primarily participated in processes such as amino acid metabolism, fatty acid synthesis, and disease. Notably, the consumption of medusa resulted in a significant reduction in nine lysophospholipids associated with cardiovascular disease and inflammation. Pearson's correlation coefficient analysis revealed associations between specific microorganisms and metabolites, indicating that Cobetia, Weissella, and Macrococcus exhibited an increased abundance in the SM group, positively correlating with apocynin, 12-Hete, and delta 9-THC-d3. The indicator bacteria Psychrobacter reduced in the SM group, exhibiting a negative correlation with cystathionine (a compound involved in glutathione synthesis). Overall, the supplementation of medusa may confer a beneficial effect on the immunity of the fish. This study contributes to the theoretical framework for fish feed development.

Structural characterization of N-acyl-homoserine lactones from bacterial quorum sensing using LC-MS/MS analyses after Paternò-Büchi derivatization in solution.

Bacterial quorum sensing is a chemical language allowing bacteria to interact through the excretion of molecules called autoinducers, like N-acyl-homoserine lactones (AHLs) produced by Gram-negative Burkholderia and Paraburkholderia bacteria known as opportunistic pathogens. The AHLs differ in their acyl-chain length and may be modified by a 3-oxo or 3-hydroxy substituent, or C = C double bonds at different positions. As the bacterial signal specificity depends on all of these chemical features, their structural characterization is essential to have a better understanding of the population regulation and virulence phenomenon. This study aimed at enabling the localization of the C = C double bond on such specialized metabolites while using significantly lower amounts of biological material. The approach is based on LC-MS/MS analyses of bacterial extracts after in-solution derivatization by a photochemical Paternò-Büchi reaction, leading to the formation of an oxetane ring and subsequently to specific fragmentations when performing MS/MS experiments. The in-solution derivatization of AHLs was optimized on several standards, and then the matrix effect of bacterial extracts on the derivatization was assessed. As a proof of concept, the optimized conditions were applied to a bacterial extract enabling the localization of C = C bonds on unsaturated AHLs.

Genomic and metabolomic insights into the selection and differentiation of bioactive compounds in citrus

Bioactive compounds are playing an increasingly prominent role in breeding functional and nutritive fruit crops such as citrus. However, the genomic and metabolic basis for the selection and differentiation underlying bioactive compounds variations in citrus remain poorly understood. Here, we constructed a species-level variation atlas of genomes and metabolomes using 299 citrus accessions. A total of 19,829 significant SNPs were targeted to 653 annotated metabolites, among which multiple significant signals were identified for secondary metabolites, especially flavonoids. Significantly differential accumulation of bioactive compounds in phenylpropane pathway, mainly flavonoids and coumarins, were unveiled across ancestral citrus species during differentiation, which is likely associated with the divergent haplotype distribution and/or expression profiles of relevant genes, including p-coumaroyl coenzyme A 2'-hydroxylases, flavone synthases, cytochrome P450 enzymes, prenyltransferases and UDP-glycosyltransferases. Moreover, we elucidated the citrus varieties with excellent antioxidant and anticancer capacities, clarifying the robust associations between distinct bioactivities and specific metabolites. Thus, these findings provide citrus breeding options for enrichment of beneficial flavonoids and avoidance of the potential risk of coumarins. This study will illuminate the application of genomic and metabolic engineering strategies in developing modern healthy citrus cultivars.

Mediation-adjusted multivariable Mendelian randomisation study identified novel metabolites related to mental health

BackgroundFrom the pathway perspective, metabolites have the potential to improve knowledge about the aetiology of psychiatric diseases. Previous studies suggested a link between specific blood metabolites and mental disorders, but...

Investigation of novel metabolites generated by Torulaspora delbrueckii to promote the aroma biosynthesis in Saccharomyces cerevisiae during wine fermentation

The co-fermentation of Saccharomyces cerevisiae and non-Saccharomyces has been recognized as an effective strategy for improving the quality of wine aroma. One of the most critical factors for the aroma enhancement is the yeast-produced metabolites, but the underlying mechanisms remain poorly understood. In this study, we used a cell/medium separation strategy to investigate the effects of metabolites generated by Torulaspora delbrueckii on the aroma biosynthesis in S. cerevisiae. The results demonstrated that T. delbrueckii metabolites enhanced the production of ethyl octanoate, ethyl decanoate, isoamyl acetate, and isopentanol within S. cerevisiae. Upregulation of aroma-related genes, including EEB1, SLI1, BAP3, BAT1, PDC1, and PDC5 in S. cerevisiae, was responsible for the aroma enhancement. The untargeted metabolomic analysis determined a total of 869 T. delbrueckii metabolites, in which three novel metabolites were identified to promote the aroma formation in S. cerevisiae. Specifically, 3-amino-4-methylpentanoic acid stimulated the levels of ethyl octanoate (up to 42.55%) and ethyl decanoate (up to 31.92%), while 4-methylaminobutyric acid and citraconic acid increased the production of ethyl hexanoate (up to 59.19%) and isoamyl acetate (up to 32.26%). A comprehensive understanding of the specific yeast metabolites provides a robust foundation for winemakers to purposefully modulate the aromatic characteristics of wines.

Suspect screening candidate exposure biomarkers of acetyl tributyl citrate and acetyl triethyl citrate after human oral administration

Acetyl tributyl citrate (ATBC) and acetyl triethyl citrate (ATEC) are widely used as plasticizers, but their metabolites as exposure biomarkers for biomonitoring, as well as approximate human metabolic pathways, are not well understood. This study addresses this knowledge gap by conducting suspect screening to propose specific metabolites in human urine as potential biomarkers of exposure and explore their kinetic profiles. Ten volunteers were administered deuterium labeled ATBC (ATBC-d3) and seven received ATEC or deuterium labeled ATEC (ATEC-d3), with urine samples collected over 48 h post-administration. Employing ultra-performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UPLC-qTOF/MS), six metabolites of ATBC were consistently detected, including (OH)3-ATBC-d3, ADBC-d3, OH-ADBC-d3, DBC, OH-DBC, and OH-DBA. For ATEC, four metabolites were identified: ADEC-d3, AMEC-d3, OH-ADEC-d3, and DEC. Based on their high detection frequency, relative response, and specificity to their parent compounds, ADBC-d3 and OH-ADBC-d3 were identified as promising candidate biomarkers for ATBC exposure, while ADEC-d3 emerged as a suitable biomarker for ATEC. Estimated urinary elimination half-lives ranged from 1.0 to 9.9 h for ATBC metabolites and 1.6 to 3.0 h for ATEC metabolites. One-compartment kinetic modeling provided preliminary insights into metabolite kinetics. The study suggests that ATBC may undergo more hydroxylation compared to ATEC, but further quantitative analysis is needed to confirm this observation. This research advances the understanding of ATBC and ATEC metabolism in humans, providing a foundation for future exposure assessments and toxicological studies. The identified biomarkers and preliminary metabolic profiles offer valuable starting points for biomonitoring and risk assessment of these alternative plasticizers.