Critical Metabolites Research Articles

Novel predictive biomarkers for atonic postpartum hemorrhage as explored by proteomics and metabolomics.

Postpartum hemorrhage (PPH) is the leading cause of maternal mortality worldwide, with uterine atony accounting for approximately 70% of PPH cases. However, there is currently no effective prediction method to promote early management of PPH. In this study, we aimed to screen for potential predictive biomarkers for atonic PPH using combined omics approaches. Collection of cervicovaginal fluid (CVF) samples from 27 women with atonic PPH and 32 women with normal delivery was performed for metabolomic (LC-MS/MS) and proteomic (LC-MS/MS) detection and subsequent confirmation experiments in this nested case-control study. Mass spectrum and enzyme-linked immunosorbent assays (ELISA) were used to validate significantly different metabolites and proteins for screening potential biomarkers of atonic PPH. Furthermore, multivariate logistic regressions were performed for the prediction of PPH using the identified biomarkers mentioned above, and the area under the curve (AUC) was computed. We identified 216 and 311 metabolites under positive and negative ion modes, respectively, as well as 1974 proteins. The PPH group had significant differences in metabolites and proteins belonging to the β-alanine metabolic pathway. Specifically, the PPH group had downregulation of critical metabolites, including histidine and protein dihydropyrimidine dehydrogenase (DPYD). Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) functional enrichment analysis of significantly differentially expressed proteins revealed that atonic PPH was associated with T cell- and macrophage-related immune inflammatory responses. Furthermore, we verified that concentrations of histidine (350.85 ± 207.87 vs. 648.33 ± 400.87) and DPYD (4.01 ± 2.56 vs. 10.96 ± 10.71), and immune cell-related proteins such as CD163 (0.29 ± 0.19 vs. 1.51 ± 0.83) and FGL2 (5.98 ± 4.23 vs. 11.37 ± 9.42) were significantly lower in the PPH group. Finally, the AUC for independent prediction of PPH using CD163, histidine, DPYD, and FGL2 are 0.969 (0.897-1), 0.722 (0.536-0.874), 0.719 (0.528-0.864), and 0.697 (0.492-0.844), respectively. A relatively high predictive efficiency was obtained when using joint histidine, DPYD, CD163, and FGL2, with AUC = 0. 964 (0.822-1). This study suggested that immune inflammation may play a role in the occurrence of PPH. The metabolite histidine and proteins of DPYD, CD163, and FGL2 in CVF were associated with uterine atony and could be used as predictive biomarkers for atonic PPH.

Fluorescent CdTe/ZnS Core/Shell Quantum Dots for Sensitive Metabolite Detection in Real Samples.

This study highlights the aqueous synthesis of CdTe/ZnS core/shell quantum dots (QDs) and their application as fluorescence sensors for detecting critical metabolites, including folic acid, glucose, and vitamin C, in real biological samples. The synthesized QDs exhibit excellent quantum efficiency, stability, and biocompatibility, enhanced by mercaptopropionic acid (MPA) ligands, enabling eco-friendly and accurate sensing. Detection limits of 0.84µg/mL for folic acid, 0.33mM for glucose, and 1.15µg/mL for vitamin C were achieved with high linearity (R2 > 0.97). These results underscore the potential of CdTe/ZnS QDs in advanced biosensing technologies, offering sensitive and selective metabolite detection through a robust FRET-based mechanism. The versatility and aqueous solubility of these QDs pave the way for their integration into multiplex diagnostic systems for enhanced biomedical applications.

16S rRNA and metabolomics reveal the key microbes and key metabolites that regulate diarrhea in Holstein male calves.

Diarrhea is a prevalent disease among calves, which significantly hinders their growth and development, thereby impacting farm productivity and revenue. This study aimed to investigate the impact of diarrhea on calf growth. Holstein male calves with similar birth weight (39.5 ± 4.2 kg) were included in this study, and key parameters such as fecal score, diarrhea incidence, and growth performance from birth to weaning were measured. Rectal fecal samples from both diarrheic (n = 24) and healthy calves (n = 24) aged 1-4 weeks were analyzed using 16S rRNA gene sequencing and untargeted metabolomics. Our findings indicated a high prevalence of diarrhea among calves between 1-4 weeks of age on pasture, which led to a marked decrease in growth performance, including average daily gain. At the genus level, the relative abundance of GCA-900066575 in one-week-old diarrheic calves was significantly higher; Escherichia-Shigella and Pseudoflavonifractor were more abundant in two-week-old calves; while Tyzzerella and Lachnospiraceae_UCG-004 increased significantly in four-week-old calves, and correlated negatively with average daily gain, suggesting that these bacteria may promote the occurrence of diarrhea. Correlation analysis revealed that fecal metabolites such as arachidonic acid, cis-vaccenic acid, oleic acid, choline, creatinine, and others were significantly negatively correlated with calf growth performance and were significantly increased in diarrheic calves. WGNCA identified that dark magenta module metabolites were significantly associated with diarrhea traits from 1-4 weeks. Thirteen metabolites, including glycerophospholipids (such as 1-stearoyl-2-hydroxy-sn-glycero-3-phosphoethanolamine), fatty acids (such as dodecanoic acid), and arachidonic acid, were positively correlated with GCA-900066575, Escherichia-shigella, Tyzzerella, and Clostridium_butyricum, but negatively correlated with UBA1819, Lachnoclostridium_sp_YL32, and Clostridium_scindens. Therefore, GCA-900066575, Escherichia-shigella, Lachnospiraceae_UCG-004, and Tyzzerella are likely key bacterial genera causing diarrhea in calves, while arachidonic acid, glycerol phospholipids, and fatty acids are critical metabolites associated with this condition. These alterations in the fecal microbiota and metabolite composition were found to be the principal contributors to growth retardation in diarrheic calves.

Metabolomics insights into doxorubicin and 5-fluorouracil combination therapy in triple-negative breast cancer: a xenograft mouse model study.

Breast cancer is one of the most prevalent malignancies and a leading cause of death among women worldwide. Among its subtypes, triple-negative breast cancer (TNBC) poses significant clinical challenges due to its aggressive behavior and limited treatment options. This study aimed to investigate the effects of doxorubicin (DOX) and 5-fluorouracil (5-FU) as monotherapies and in combination using an established MDA-MB-231 xenograft model in female BALB/C nude mice employing advanced metabolomics analysis to identify molecular alterations induced by these treatments. We conducted comprehensive plasma and tumor tissue sample profiling using ultra-high-performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS). Each treatment group exhibited unique metabolic profiles in plasma and tumor analysis. Univariate and enrichment analyses identified alterations in metabolic pathways. The combination treatment of DOX + 5-FU induced the most extensive metabolic alterations disrupting key pathways including purine, pyrimidine, beta-alanine, and sphingolipid metabolism. It significantly reduced critical metabolites such as guanine, xanthine, inosine, L-fucose, and sphinganine, demonstrating enhanced cytotoxic effects compared to individual treatments. The DOX treatment uniquely increased ornithine levels, while 5-FU altered sphingolipid metabolism, promoting apoptosis. This in vivo study highlights TNBC's metabolic alterations to chemotherapeutics, identifying potential biomarkers like L-fucose and beta-alanine, and provides insights for improving treatment strategies.

Integrated analysis of physiological and metabolic data uncovers essential dynamic mechanisms involved in the maturation of cigar tobacco leaves

The quality of cigar tobacco leaves is profoundly affected by the timing of their harvest, with both early and late collections resulting in inferior characteristics. While the relationship between maturity and physiological metabolic processes is acknowledged, a comprehensive understanding of the physiological behavior of cigar leaves harvested at different stages remains elusive. This research investigated the physiological and metabolomic profiles of the cigar tobacco variety CX-014, grown in Danjiangkou City, Hubei Province, with leaves sampled at 35 (T1), 42 (T2), 49 (T3), and 56 (T4) days post-inflorescence removal. Leaf color transitioned from green to yellow, accompanied by the appearance of white mature spots. Notable increases in photosynthetic pigments and gas exchange parameters occurred between T1 and T2, followed by decline at T3 and T4. The optimal sugar-to-nicotine and potassium-to-chlorine ratios, critical determinants of smoking quality and tobacco combustibility, were observed at T3, indicating a superior chemical balance in leaves harvested at this stage. Metabolomic analysis revealed 2153 distinct metabolites, with the most significant changes occurring between T2 and T3, highlighting critical physiological transformations during this interval. Pathway enrichment analysis via KEGG pinpointed notable shifts in amino acid synthesis pathways, particularly those involving tryptophan, alanine, and aspartate. Tryptophan metabolism and zeatin biosynthesis were substantially altered, with compounds like indolepyruvic acid, N-formylpurine nucleotide, isopentenyladenine nucleotide, and dihydrozeatin showing marked reductions at T3. This study also explored how the timing of lower leaf harvest influences the physiological processes of middle leaves, finding that a plethora of metabolites associated with the breakdown of arachidonic acid—a primitive metazoan signaler implicated in plant stress and defense networks—were abundant in T3 leaves when lower leaves were harvested 43–38 days prior. Overall, these findings elucidates the complex physiological dynamics of cigar leaves during maturation, highlighting critical metabolites involved in essential metabolic pathways.

Advancements in Mass Spectrometry-Based Targeted Metabolomics and Lipidomics: Implications for Clinical Research.

Targeted metabolomics and lipidomics are increasingly utilized in clinical research, providing quantitative and comprehensive assessments of metabolic profiles that underlie physiological and pathological mechanisms. These approaches enable the identification of critical metabolites and metabolic alterations essential for accurate diagnosis and precision treatment. Mass spectrometry, in combination with various separation techniques, offers a highly sensitive and specific platform for implementing targeted metabolomics and lipidomics in clinical settings. Nevertheless, challenges persist in areas such as sample collection, quantification, quality control, and data interpretation. This review summarizes recent advances in targeted metabolomics and lipidomics, emphasizing their applications in clinical research. Advancements, including microsampling, dynamic multiple reaction monitoring, and integration of ion mobility mass spectrometry, are highlighted. Additionally, the review discusses the critical importance of data standardization and harmonization for successful clinical implementation.

Butyrate-producing Faecalibacterium prausnitzii suppresses natural killer/T-cell lymphoma by dampening the JAK-STAT pathway

BackgroundNatural killer/T-cell lymphoma (NKTCL) is a highly aggressive malignancy with a dismal prognosis, and gaps remain in understanding the determinants influencing disease outcomes.ObjectiveTo characterise the gut microbiota feature and identify...

Integrated colon microbiome and metabolomics to elucidate the antidepressant mechanisms of the Radix Bupleuri-Radix Paeoniae Alba herb pair.

Radix Bupleuri-Radix Paeoniae Alba herb pair (RB-RPA) is the fundamental medication combination of many classic antidepressant prescriptions, and RB-RPA's antidepressant effect is well established. For an extended period, the involvement of intestinal flora in the progression of depression has been widely acknowledged. However, it remains unclear whether RB-RPA could modulate intestinal microbiota disturbances and metabolic abnormalities induced by depression. The research explores the antidepressant mechanism of RB-RPA in chronic unpredictable mild stress (CUMS) rats in terms of intestinal flora and metabolites. We identified critical gut microbial species and metabolites associated with the antidepressant effects of RB-RPA using 16S rRNA sequencing and Liquid Chromatography-Mass Spectrometry (LC-MS) metabolomics. And then, correlation analysis between critical microbiota and differential metabolites was conducted. The results demonstrate that RB-RPA significantly ameliorated depressive-like behavior in CUMS rats. RB-RPA improved intestinal flora disorders in depressed rats mainly by increasing the abundance of Lactobacillus (especially L. johnsonii), and ameliorated tryptophan synthesis and metabolism disorders in depressed rats and restored the levels of tryptophan and tryptophan microbial metabolites, such as indoleacrylic acid and 4-indoleacetaldehyde. Notably, correlation analysis showed that Lactobacillus had a significant positive correlation with tryptophan, indoleacrylic acid, and 4-indoleacetaldehyde. In conclusion, RB-RPA can improve the disorder of intestinal flora by increasing the abundance of Lactobacillus and improve the metabolic disorder of depressed rats by regulating tryptophan metabolism, thus exerting antidepressant effects.

RNAseq and targeted metabolomics implicate RIC8 in regulation of energy homeostasis, amino acid compartmentation, and asexual development in Neurospora crassa.

Resistance to inhibitors of cholinesterase-8 (RIC8) is an important regulator of heterotrimeric Gα proteins in eukaryotes. In the filamentous fungus Neurospora crassa, mutants lacking ric8 undergo inappropriate asexual development (macroconidiation) during submerged growth. Our work identifies a role for RIC8 in regulating expression of transporter genes that retain arginine and ornithine in the vacuole (equivalent of the animal lysosome) and relates this function to the developmental defect. Arginine is a critical cellular metabolite, both as an amino acid for protein synthesis and as a precursor for an array of compounds, including proline, ornithine, citrulline, polyamines, creatine phosphate, and nitric oxide. These results have broad relevance to human physiology and disease, as arginine modulates immune, vascular, hormonal, and other functions in humans.

Structure-based clustering and mutagenesis of bacterial tannases reveals the importance and diversity of active site-capping domains.

Tannins are critical plant defense metabolites, enriched in bark and leaves, that protect against microorganisms and insects by binding to and precipitating proteins. Hydrolyzable tannins contain ester bonds which can be cleaved by tannases-serine hydrolases containing so-called "cap" domains covering their active sites. However, comprehensive insights into the biochemical properties and structural diversity of tannases are limited, especially regarding their cap domains. We here present a code pipeline for structure prediction-based hierarchical clustering to categorize the whole family of bacterial tannases, and have used it to discover new types of cap domains and other structural insertions among these enzymes. Subsequently, we used two recently identified tannases from the gut/soil bacterium Clostridium butyricum as model systems to explore the biochemical and structural properties of the cap domains of tannases. We demonstrate using molecular dynamics and mutagenesis that the cap domain covering the active site plays a major role in enzyme substrate preference, inhibition, and activity-despite not directly interacting with smaller substrates. The present work provides deeper knowledge into the mechanism, structural dynamics, and diversity of tannases. The structure-based clustering approach presents a new way of classifying any other enzyme family, and will be of relevance for enzyme types where activity is influenced by variable loop or insert regions appended to a core protein fold.

CsWRKY53 and CsWRKY40 synergistically regulate L-theanine hydrolysis by abscisic acid signaling pathway during tea withering.

L-Theanine hydrolysis in tea leaves not only reduces tea product quality but also decreases their health benefits. Postharvest dehydration-induced abscisic acid (ABA) contributes to the L-theanine hydrolysis, but the specific mechanism is unexplored. Based on transcriptome analysis and gene silencing experiments, CsNCED3a was shown to be a key gene for ABA synthesis in harvested tea leaves, and CsABF7 up-regulated the expression of CsWRKY40, a transcription factor (TF) that directly regulates a L-theanine hydrolysis gene, resulting in the loss of L-theanine. CsWRKY53 and CsWRKY40 activated CsNCED3a expression. The CsWRKY53-CsWRKY40 complex exhibited a stronger regulatory effect than individual TFs. These findings reveal an ABA-mediated regulatory pathway for L-theanine hydrolysis, and highlight the pivotal role of ABA in postharvest metabolism of critical flavor-contributing metabolites in tea leaves.

Optimizing HMG-CoA Synthase Expression for Enhanced Limonene Production in Escherichia coli through Temporal Transcription Modulation Using Optogenetics.

Overexpression of a single enzyme in a multigene heterologous pathway may be out of balance with the other enzymes in the pathway, leading to accumulated toxic intermediates, imbalanced carbon flux, reduced productivity of the pathway, or an inhibited growth phenotype. Therefore, optimal, balanced, and synchronized expression levels of enzymes in a particular metabolic pathway is critical to maximize production of desired compounds while maintaining cell fitness in a growing culture. Furthermore, the optimal intracellular concentration of an enzyme is determined by the expression strength, specific timing/duration, and degradation rate of the enzyme. Here, we modulated the intracellular concentration of a key enzyme, namely HMG-CoA synthase (HMGS), in the heterologous mevalonate pathway by tuning its expression level and period of transcription to enhance limonene production in Escherichia coli. Facilitated by the tuned blue-light inducible BLADE/pBad system, we observed that limonene production was highest (160 mg/L) with an intermediate transcription level of HMGS from moderate light illumination (41 au, 150 s ON/150 s OFF) throughout the growth. Owing to the easy penetration and removal of blue-light illumination from the growing culture which is hard to obtain using conventional chemical-based induction, we further explored different induction patterns of HMGS under strong light illumination (2047 au, 300 s ON) for different durations along the growth phases. We identified a specific timing of HMGS expression in the log phase (3-9 h) that led to optimal limonene production (200 mg/L). This is further supported by a mathematical model that predicts several periods of blue-light illumination (3-9 h, 0-9 h, 3-12 h, 0-12 h) to achieve an optimal expression level of HMGS that maximizes limonene production and maintains cell fitness. Compared to moderate and prolonged transcription (41 au, 150 s ON/150 s OFF, 0-73 h), strong but time-limited transcription (2047 au, 300 s ON, 3-9 h) of HMGS could maintain its optimal intracellular concentration and further increased limonene production up to 92% (250 mg/L) in the longer incubation (up to 73 h) without impacting cell fitness. This work has provided new insight into the "right amount" and "just-in-time" expression of a critical metabolite enzyme in the upper module of the mevalonate pathway using optogenetics. This study would complement previous findings in modulating HMGS expression and potentially be applicable to heterologous production of other terpenoids in E. coli.

Identification of novel hypertension biomarkers using explainable AI and metabolomics

BackgroundThe global incidence of hypertension, a condition of elevated blood pressure, is rising alarmingly. According to the World Health Organization’s Qatar Hypertension Profile for 2023, around 33% of adults are affected by hypertension. This is a significant public health concern that can lead to serious health complications if left untreated. Metabolic dysfunction is a primary cause of hypertension. By studying key biomarkers, we can discover new treatments to improve the lives of those with high blood pressure.AimsThis study aims to use explainable artificial intelligence (XAI) to interpret novel metabolite biosignatures linked to hypertension in Qatari Population.MethodsThe study utilized liquid chromatography-mass spectrometry (LC/MS) method to profile metabolites from biosamples of Qatari nationals diagnosed with stage 1 hypertension (n = 224) and controls (n = 554). Metabolon platform was used for the annotation of raw metabolite data generated during the process. A comprehensive series of analytical procedures, including data trimming, imputation, undersampling, feature selection, and biomarker discovery through explainable AI (XAI) models, were meticulously executed to ensure the accuracy and reliability of the results.ResultsElevated Vanillylmandelic acid (VMA) levels are markedly associated with stage 1 hypertension compared to controls. Glycerophosphorylcholine (GPC), N-Stearoylsphingosine (d18:1/18:0)*, and glycine are critical metabolites for accurate hypertension prediction. The light gradient boosting model yielded superior results, underscoring the potential of our research in enhancing hypertension diagnosis and treatment. The model’s classification metrics: accuracy (78.13%), precision (78.13%), recall (78.13%), F1-score (78.13%), and AUROC (83.88%) affirm its efficacy. SHapley Additive exPlanations (SHAP) further elucidate the metabolite markers, providing a deeper understanding of the disease’s pathology.ConclusionThis study identified novel metabolite biomarkers for precise hypertension diagnosis using XAI, enhancing early detection and intervention in the Qatari population.

Senolytics Enhance the Longevity of Caenorhabditis elegans by Altering Betaine Metabolism.

Aging triggers physiological changes in organisms that are tightly linked to metabolic changes. Senolytics targeting many fundamental aging processes are currently being developed. However, the host metabolic response to natural senescence and the molecular mechanism underlying the antiaging benefits of senolytics remain poorly understood. In this study, we investigated metabolic changes during natural senescence based on the Caenorhabditis elegans model and pinpointed potential biomarkers linked to the benefits of senolytics. These results suggest that age-dependent metabolic changes during natural aging occur in C elegans. Betaine was identified as a crucial metabolite in the natural aging process. We explored the metabolic effects of aging interventions by administering 3 antiaging drugs-metformin, quercetin, and minocycline-to nematodes. Notably, betaine expression significantly increased under the 3 antiaging drug treatments. Our findings demonstrated that betaine supplementation extends lifespan, primarily through pathways associated with the forkhead box transcription factor (FoxO) signaling pathway, the p38-mitogen-activated protein kinase (MAPK) signaling pathway, autophagy, the longevity regulating pathway, and the target of rapamycin (mTOR) signaling pathway. In addition, autophagy and free radicals are altered in betaine-treated nematodes. Overall, we found that betaine is a critical metabolite during natural aging and that senolytics extend the lifespan of nematodes by increasing betaine levels and promoting autophagy and antioxidant activity. This finding suggests that betaine could be a novel therapeutic target for promoting longevity.

Leveraging multi-omics tools to comprehend responses and tolerance mechanisms of heavy metals in crop plants.

Extreme anthropogenic activities and current farming techniques exacerbate the effects of water and soil impurity by hazardous heavy metals (HMs), severely reducing agricultural output and threatening food safety. In the upcoming years, plants that undergo exposure to HM might cause a considerable decline in the development as well as production. Hence, plants have developed sophisticated defensive systems to evade or withstand the harmful consequences of HM. These mechanisms comprise the uptake as well as storage of HMs in organelles, their immobilization via chemical formation by organic chelates, and their removal using many ion channels, transporters, signaling networks, and TFs, amid other approaches. Among various cutting-edge methodologies, omics, most notably genomics, transcriptomics, proteomics, metabolomics, miRNAomics, phenomics, and epigenomics have become game-changing approaches, revealing information about the genes, proteins, critical metabolites as well as microRNAs that govern HM responses and resistance systems. With the help of integrated omics approaches, we will be able to fully understand the molecular processes behind plant defense, enabling the development of more effective crop protection techniques in the face of climate change. Therefore, this review comprehensively presented omics advancements that will allow resilient and sustainable crop plants to flourish in areas contaminated with HMs.

MOGAT3-Mediated DAG Accumulation Drives Acquired Resistance to Anti-BRAF/EGFR Therapy in BRAFV600E-Mutant Metastatic Colorectal Cancer.

BRAFV600E-mutant metastatic colorectal cancer (mCRC) is associated with poor prognosis. The combination of anti-BRAF/EGFR (encorafenib/cetuximab) treatment for patients with BRAFV600E-mutant mCRC improved clinical benefits; unfortunately, inevitable acquired resistance limits the treatment outcome, and the mechanism has not been validated. Here, we discovered that monoacylglycerol O-Acyltransferase 3 (MOGAT3) mediated diacylglycerol (DAG) accumulation contributed to acquired resistance to encorafenib/cetuximab by dissecting BRAFV600E-mutant mCRC patient-derived xenograft (PDX) model exposed to encorafenib/cetuximab administration. Mechanistically, upregulated MOGAT3 promotes DAG synthesis and reduces fatty acid oxidation (FAO)-promoting DAG accumulation and activating PKCα-CRAF-MEK-ERK, driving acquired resistance. Resistance-induced hypoxia promotes MOGAT3 transcriptional elevation; simultaneously, MOGAT3-mediated DAG accumulation increases HIF1A expression in translation level through PKCα-CRAF-eIF4E activation, strengthening the resistance status. Intriguingly, reducing intratumoral DAG by fenofibrate or Pf-06471553 restores the antitumor efficacy of encorafenib/cetuximab on resistant BRAFV600E-mutant mCRC, interrupted PKCα-CRAF-MEK-ERK signaling. These findings reveal the critical metabolite DAG as a modulator of encorafenib/cetuximab efficacy in BRAFV600E-mutant mCRC, suggesting that fenofibrate may prove beneficial for resistant BRAFV600E-mutant mCRC patients.

Electronic senses and UPLC-Q-TOF/MS combined with chemometrics analyses of Cynanchum species (Baishouwu).

Baishouwu, derived from Cynanchum auriculatum (CA) Royle ex Wight, Cynanchum bungei (CB) Decne., and Cynanchum wilfordii (CW) (Maxim.) Hemsl., is a valuable traditional Chinese medicine. CA is also recognized as a new food resource by China's National Health Commission. Given the considerable variations in flavor and chemical composition among these species and lack of their qualitative assessments, accurately differentiating between the species constituting Baishouwu is essential. To develop a method combining electronic tongue (E-tongue), electronic nose (E-nose), and ultra-performance liquid chromatography-quadrupole-time of flight/mass spectrometry (UPLC-Q-TOF/MS) to differentiate between Baishouwu samples. Fifteen batches of Baishouwu samples were analyzed using E-tongue, E-nose, and UPLC-Q-TOF/MS. Flavor differences and key differential metabolites were determined through principal component analysis and orthogonal partial least squares discriminant analysis. E-tongue results revealed umami, sweetness, and richness as the predominant flavors of Baishouwu, with CA having the highest umami response, CW exhibiting the highest bitterness, and CB the highest sweetness. E-nose sensors showed consistent responses across species, with variations in signal strength; W1W and W2W sensors showed the highest response values. A total of 158 and 41 characteristic variables in the positive and negative ion modes, respectively, were selected as candidate differential metabolites, of which 29 and 14 were confirmed through database comparison. Eight critical differential metabolites, including C21 steroids and acetophenone compounds, were identified. This study presents a strategy for differentiating among the species constituting Baishouwu, providing a basis for broader application and establishing quality standards for these medicinal compounds.

A Klebsiella rhizobacterium deregulates the metabolism of phytopathogenic Aspergillus flavus during in-vitro assays and confers protective functions

In previous investigations, we have identified a rhizobacterium (Klebsiella sp. MBE02) that confers host protection against several phytopathogenic fungi. For instance, this rhizobacterium prevents Aspergillus flavus infection and promotes peanut growth and fitness in controlled and field-conditions. The mechanistic basis of the protective function offered by this rhizobacterium is not completely understood. MBE02 directly restricts the growth of the pathogenic fungi, which led us to hypothesize that it may strongly dysregulate the metabolism of A. flavus, and inhibit critical metabolic processes of the fungus, which severely restricts pathogen growth. We have tested this hypothesis by using untargeted metabolite profiling. Sixty-nine A. flavus metabolites accumulated differentially due to the presence of the MBE02. MBE02 could inhibit several important metabolic pathways, which include the biosynthesis of critical primary metabolites such as amino acids and fatty acids. It also impacts energy metabolism of the fungus, and that the accumulation of several structural components, including of the cell wall, were strongly inhibited. MBE02 abrogated the accumulation of disease-causing metabolites in A. flavus, whereas the accumulation of metabolites that inhibit fungal growth were enhanced. On the other hand, A. flavus did not strikingly impact the accumulation of metabolites of the MBE02. Our investigation supports the hypothesis that Klebsiella sp. MBE02 mediates protective function by directly impairing the pathogen’s metabolism.

Transcriptome sequencing and identification of full-length genes involved in the biosynthesis of anticancer compounds Oleanolic acid and Ursolic acid in Achyranthes aspera L.

Achyranthes aspera is renowned for its rich medicinal properties since the Ayurvedic era. This plant is known for the presence of experimentally validated anticancer compounds like oleanolic acid (OA) and ursolic acid (UA). Our study involved sequencing the RNA from the root tissue of A. aspera to elucidate the genes responsible for synthesizing these two critical secondary metabolites. Through RNA-Seq analysis, we assembled approximately 167,698 transcripts, averaging 847 base pairs in length, with an N50 value of 1509 bp. From this data, we mapped 604 sequences involved in the metabolism of terpenoids and polyketide pathways. Among them, 241 transcripts were mapped to the triterpenoid biosynthesis pathway, which included 127 transcripts involved in OA and UA biosynthesis. From these transcripts, we identified 22 full-length genes coding for all the 21 enzymes required for OA and UA biosynthesis. Identifying these full-length genes will lead to a better understanding of the pathway and adopting genetic engineering approaches.

Growth and physiological metabolic regulation mechanisms of the dominant plant Leymus secalinus in alpine meadow under nitrogen deposition

Nitrogen (N) deposition is an important pathway that affects the growth and development of alpine grassland plants. Under N deposition, Leymus secalinus has become the most dominant species in the alpine meadow of the Qinghai-Tibetan Plateau. However, its adaptive mechanisms to N deposition are still unknown. Therefore, we analyzed the physiological indices of Leymus secalinus under different N deposition levels (CK, 0 kg N ha−1 yr−1; N1, 8 kg N ha−1 yr−1; N3, 40 kg N ha−1 yr−1; N5, 72 kg N ha−1 yr−1) and focused on its growth and metabolism. The results indicated that the leaf carbon (C), N, amino acid (AA), and photosynthetic pigment contents in Leymus secalinus were significantly increased under N deposition, its endogenous hormone levels were regulated and the activities of N metabolism-related enzymes were enhanced. Metabolomics analysis further showed that the metabolites changed significantly and were mostly enriched in the amino acid metabolic pathway. Among them, glutamine and aspartic acid played key roles in N deposition for dominant growth of Leymus secalinus by regulating N and amino acid metabolism. These analyses unveiled the physiological and biochemical changes of dominant species in response to N deposition, identifying critical metabolites involved in this process. Furthermore, these findings provide substantial evidence explaining the ecological phenomenon of Leymus secalinus emerging as a dominant species under N deposition, serving as a data reference for understanding the physiological response and adaptation to N deposition in alpine grassland plants.