Tandem Mass Spectrometry Research Articles

Hair and Saliva Endocannabinoid and Steroid Hormone Analysis by Liquid Chromatography Paired with Tandem Mass Spectrometry.

Endocannabinoids are lipid neurotransmitters that play an important part in human health. Recent methods have found that quantification of endocannabinoids in hair and saliva samples is possible using liquid chromatography paired with tandem mass spectrometry (LC-MS/MS). This chapter describes two simple sample preparation methods that can be used to prepare hair and saliva samples for analysis using LC-MS/MS. Our LC-MS/MS method can be applied to both hair and saliva samples and is sufficiently sensitive for endocannabinoid, as well as steroid hormone, quantification in both of these sample matrices. This chapter provides a comprehensive description of how this can be achieved and provides tips and tricks for troubleshooting problems users may experience.

Metabolic status is a key factor influencing proteomic changes in ewe granulosa cells induced by chronic BPS exposure.

Bisphenol S (BPS) is the main substitute for bisphenol A (BPA), a well-known plasticiser and endocrine disruptor. BPS disrupts ovarian function in several species. Moreover, a few studies have reported that the effects of BPS might be modulated by the metabolic status, and none have characterised the granulosa cell (GC) proteome after chronic BPS exposure. This study aimed to decipher the mechanisms of action of chronic BPS exposure on the proteome of ewe GCs while considering the interaction between a deliberate contrasted metabolism and reproductive function. Forty ewes were split into two groups with contrasted diets: restricted (R, n = 20) and well-fed (WF, n = 20). The R and WF ewes were subdivided according to the dose of BPS administered through the diet (0-50µg/kg/day), forming four groups: R0, R50, WF0 and WF50. After 3-month BPS daily exposure, GCs were recovered during the pre-ovulatory stage and proteins were analysed by nano-liquid chromatography coupled with tandem mass spectrometry. Chronic exposure to BPS affected the GC proteome differently according to the ewe metabolic status. Fifty-nine out of 958 quantified proteins were differentially abundant between groups and are mainly involved in carbohydrate and lipid pathways. Unsupervised hierarchical clustering of differentially abundant proteins (DAPs) identified four clusters of 34, 6, 5 and 14 proteins according to the BPS exposure and diet interaction. Pairwise comparisons between groups also revealed a strong effect of BPS exposure and diet interaction. Functional analysis of DAPs highlighted that BPS upregulated β-glucuronidase (GUSB; p = 0.002), a protein especially able to deconjugate bisphenol glucuronides (BP-g). Moreover, among unexposed ewes, GUSB was detected only in well-fed ewes. Conjugation of glucuronides inhibits the oestrogenic activity of bisphenols. Upregulation of GUSB in ewes dosed with BPS would prolong the oestrogenic effects of BPS by deconjugating BPS-g into free BPS. In addition, literature has reported an up-regulation of GUSB in people suffering from obesity. Therefore, people suffering from obesity could be subjected to prolonged and aggravated exposure to BPS. These data highlighted the deleterious effects of BPS and its interaction with metabolic status.

Blood metabolomic profile in patients with type 2 diabetes mellitus with diabetic peripheral neuropathic pain.

This study aimed to identify metabolic markers for diabetic peripheral neuropathic pain (DPNP) in patients with type 2 diabetes mellitus (T2DM). Blood metabolite levels in the amino acid, biogenic amine, sphingomyelin, phosphatidylcholine (PC), carnitines, and hexose classes were analyzed in nondiabetic control (n = 27), T2DM without DPNP (n = 58), and T2DM with DPNP (n = 29) using liquid chromatography tandem mass spectrometry. Variable importance projection (VIP) evaluation by partial least squares discriminant analysis was performed on clinical parameters and metabolites. Sixteen variables with VIP > 1.0 (P < 0.05) were identified across all patient groups, and 5 variables were identified to discriminate between the two T2DM groups. DPNP patients showed elevated fasting blood glucose, glutamate, PC aa C36:1, lysoPC a C18:1, and lysoPC a C18:2, while low-density lipoprotein cholesterol, phenylalanine, and tryptophan were reduced. Glutamate, lysoPC a C18:1, and lysoPC a C18:2 discriminated T2DM with DPNP from those without DPNP with an AUC of 0.671. The AUC was improved to 0.765 when ratios of metabolite pairs were considered. Blood metabolites include glutamate, and phospholipid-related metabolites implicated in neuropathic pain may have the potential as biomarkers for DPNP. Further investigation is required to understand the mechanism of action of these altered metabolites in DPNP.

Detection of "smoke powder" etomidate and its metabolite etomidate acid in blood and urine by UHPLC-MS-MS: application in authentic cases.

Recently, etomidate has been widely used as an alternative in illicit drug market. It is usually added to regular cigarette tobacco (commonly known as "cigarette powder") or mixed in e-cigarette oil sold through the Internet, retail stores, or entertainment outlets and other channels. An ultra-high performance liquid chromatography tandem mass spectrometry method was developed to quantify etomidate and etomidate acid in human blood and urine. The limit of detection (LOD) of etomidate and etomidate acid in blood is 0.5 and 2 ng/mL, respectively, and the lower limit of quantification (LLOQ) is 1 and 5 ng/mL, respectively. The LOD of etomidate and etomidate acid in urine is 1 and 2 ng/mL, respectively, and the LLOQ is 2 and 5 ng/mL, respectively. The precision, accuracy, recoveries, and matrix effects of etomidate and etomidate acid determinations in blood and urine met the requirements for methodological validation. The method was successfully applied to the identification and quantification of etomidate and etomidate acid in blood and urine of 62 forensic cases. The concentration of etomidate ranged from 1.52 to 8.41 ng/mL (positive cases, n = 5) and the concentration of etomidate acid ranged from 2.76 to 112 ng/mL (positive cases, n = 5) in blood. The concentrations of etomidate and etomidate acid in urine samples were 2.64-79,300 ng/mL (positive cases, n = 59) and 6.11-518,000 ng/mL (positive cases, n = 60), respectively. Therefore, the concentration of etomidate in blood and urine is mostly higher than that of etomidate.

Advancing Targeted Metabolomics Using Cyanopropyl-Based Liquid Chromatography Tandem Mass Spectrometry.

The change of metabolic pathways is recognized as the key to disease discovery prompting the development of ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS)-based quantitative platforms to explore the dynamic metabolite profiles of organisms. In this study, a liquid chromatography method based on cyanopropyl (CN) was developed. By adjusting the pH environment of the column, we achieved the elution of 51 metabolites spanning the most comprehensive set of biological pathways currently known. Offering rapid chromatography, efficient separation, and green chemistry benefits, the method encompasses nucleosides and nucleotides, the oxidative-redox metabolome, the glycolysis pathway, the pentose phosphate pathway, the purine de novo pathway, amino acids, and neurological disorder-related metabolites. The mass spectrometry was equipped with electrospray ionization in both positive and negative modes with scheduled multiple reactions monitoring. The validation of the method involved a comprehensive assessment of linearity, accuracy, precision, and matrix effect. The linear range was from 1.0 to 2000 ng mL-1 with a high correlation coefficient (r > 0.99). The LOD ranged from 0.1 to 10 ng mL-1, and the LOQ ranged from 0.1 to 25 ng mL-1. The overall recovery ranged from 81.3% to 117.8%, with RSD < 15.1%. Subsequently, an analysis of metabolites was conducted in dSH-SY5Y neuroblastoma cells with 6-hydroxydopamine, a commonly used neurotoxin in neurodegenerative diseases. The results demonstrate that neurotoxin-induced mitochondrial damage significantly altered related analytes, corroborating previous estimates and validating the feasibility and reliability of the bioanalytical platform.

Co-Occurrence of Mycotoxins in the Diet and in the Milk of Dairy Cows from the Southeast Region of Brazil

Mycotoxins are toxic fungi secondary metabolites that develop on feedstuffs and can be transferred into milk, thus representing a public health risk. The objective of this study was to assess the co-occurrence of mycotoxins in the diet and in the milk of dairy cows from the southeast region of Brazil. Samples of total mixed ration (TMR, n = 70) and milk (n = 70) were collected in dairy farms and subjected to multi-mycotoxin analysis using liquid chromatography coupled to tandem mass spectrometry. The aflatoxins (AFs), ochratoxin A (OTA), and T-2 and HT-2 toxins were not detected in TMR samples. In contrast, fumonisins (FBs), zearalenone (ZEN), and deoxynivalenol (DON) were detected in 100, 93, and 24% of TMR samples at mean levels of 336.7 ± 36.98, 80.32 ± 16.06 µg/kg and 292.1 ± 85.68 µg/kg, respectively. Ninety-two percent of TMR samples exhibited co-occurring mycotoxins. In milk, 54% of samples (n = 38) had detectable levels of mycotoxin, while 43% (n = 30) contained two or more types of mycotoxins. DON, FB, and ZEN metabolites (α-zearalenol and β-zearalenol) were the most frequent mycotoxins detected in the milk samples analyzed, at mean concentrations of 0.562 ± 0.112, 2.135 ± 0.296 µg/kg, 2.472 ± 0.436 µg/kg, and 0.343 ± 0.062 µg/kg, respectively. However, none of the analyzed milk samples had levels higher than the maximum permitted limit for AFM1 in Brazil (0.5 µg/L). The results of this trial highlight the concern about the co-occurrence of multiple mycotoxins in TMR and in milk, due to the possible additive or synergistic effects of these compounds. The presence of co-occurring mycotoxins in milk underscores the need for stringent preventive practices to avoid mycotoxin contamination in the diet of dairy cows in Brazil.

Multi-class cyanobacterial toxin analysis using hydrophilic interaction liquid chromatography-mass spectrometry.

Cyanobacteria produce diverse classes of toxins including microcystins, nodularins, anatoxins, cylindrospermopsins and saxitoxins, encompassing a range of chemical properties and mechanisms of toxicity. Comprehensive analysis of these toxins in cyanobacterial, environmental and biological samples generally requires multiple methods of extraction and analysis. In this work, a method was developed for the major classes of cyanotoxins, which comprised of a three-step liquid-solid extraction method using 75 % CH3CN with 0.1 % HCOOH and a hydrophilic interaction liquid chromatography (HILIC) elution gradient that provided retention of the less polar microcystins through to the highly polar saxitoxins. Detection was performed by tandem mass spectrometry in selected reaction monitoring mode with positive and negative polarity switching. Identification criteria included matching retention times and product ion ratios with available standards. In-house validation demonstrated good performance of the method including precision ranging from 1.5 (microcystin-LA) to 5.8 (gonyautoxin-2) % RSDs, and detection limits ranging from 0.01 (cylindrospermopsin) to 0.99 (gonyautoxin-3) µg/g in freeze dried material cyanobacteria. Recovery was assessed using spiked non-toxic cyanobacterial samples (Aphanizomenon sp.) and ranged from 83 (neosaxitoxin) to 107 % ([Dha7]microcystin-LR). As a demonstration of application, toxin profiles in cyanobacterial cultures, benthic and planktonic cyanobacteria field samples, and shellfish reference materials were successfully evaluated. The procedure is also amenable for extension to other polar toxin classes including domoic acid and guanitoxin. With increasing reports of cyanobacterial blooms globally, the method represents a powerful quantitative screening tool for measuring cyanotoxins across a broad range of samples.

Metabolomic Analysis and Biochemical Profiling of Cadmium-Induced Metabolic Impairment and Its Amelioration by Resveratrol

Exposure to heavy metals, particularly cadmium (Cd), poses significant health risks because of their toxic effects and potential for bioaccumulation in living organisms. This study examined the biochemical and metabolomic changes induced by Cd exposure in an animal model via advanced liquid chromatography with tandem mass spectrometry (LC-MS/MS) and biochemical assays to reveal significant disruptions in lipid and amino acid metabolism as well as alterations in key metabolic pathways. Cd exposure led to significant weight loss, hyperglycemia, and insulin resistance, indicating its role in metabolic disorders such as diabetes. The accumulation of Cd in the liver and kidneys, identified via ICP-OES, corresponded with elevated levels of liver (ALT, AST) and kidney (BUN, creatinine) biomarkers, suggesting organ-specific toxicity. At the metabolic level, Cd exposure caused the accumulation of lipid metabolites such as ceramides and sphingolipids, which are associated with insulin resistance and broader metabolic impairments. Amino acid metabolism was also significantly disrupted, with increased concentrations of key amino acids such as phenylalanine, tryptophan, and arginine affecting pathways such as the urea cycle and Krebs cycle. These metabolic disturbances are linked to oxidative stress, systemic inflammation, and impaired glucose regulation, as evidenced by elevated CRP and IL-6 levels. The protective effects of resveratrol (RSV) were clearly demonstrated in this study. RSV treatment ameliorated Cd-induced biochemical and metabolic alterations, as shown by improved glycemic control, restored lipid profiles, and normalized amino acid concentrations. Additionally, RSV significantly reduced inflammatory markers and improved liver and kidney function, highlighting its antioxidant properties and potential as a therapeutic agent against Cd toxicity. However, RSV did not significantly reduce Cd accumulation in organs, indicating that its protective effects are related to mitigating oxidative damage and metabolic disruption rather than promoting Cd excretion. This study enhances our understanding of the molecular mechanisms underlying Cd-induced metabolic impairments and highlights the therapeutic potential of RSV in combating Cd toxicity. These findings underscore the need for further research into heavy metal exposure and its mitigation to protect human health, particularly in areas of environmental contamination.

Cell-based therapies reverse the heart failure-altered right ventricular proteome towards a pre-disease state.

Congenital heart defects can lead to right ventricular (RV) pressure-overload and heart failure. Cell-based therapies, including mesenchymal stromal cells (MSCs) and c-kit positive cells (CPCs) have been studied clinically as options to restore heart function in disease states. Many studies have indicated these cells act through paracrine mechanisms to prevent apoptosis, promote cellular function, and regulate gene/protein expression. We aimed to determine the proteomic response of diseased hearts to cell therapy. We utilized a juvenile rat model of RV pressure overload created by banding the pulmonary artery (PAB). Two weeks post-banding, bone marrow-derived mesenchymal stromal cells (MSCs) and 3 populations of CPCs (nCPCs, cCPCs, ES-CPCs) were delivered to the RV free wall. RV function and cellular retention were measured for four weeks post-injection, at which point hearts were extracted and the RV was excised for liquid chromatography and tandem mass spectrometry. Resulting RV proteomes were compared and analyzed using systems biology and bioinformatics. Proteomic profiling identified 1156 total proteins from the RV, of which 5.97% were significantly changed after PAB. This disease-altered proteome was responsive to cellular therapy, with 72% of the PAB-altered proteome being fully or partially reversed by MSC therapy. This was followed by nCPCs (54%), ES-CPCs (52%), and cCPCs (39%). Systems biology and bioinformatics analysis showed MSC, nCPC, or ES-CPC cell therapy is associated with a decrease in predicted adverse cardiac effects. We also observed an effect of cell therapy on the non-altered RV proteome, however, this was associated with minor predicted pathological endpoints. Our data indicate MSCs, ES-CPCs, and nCPCs significantly reverse the PAB-altered proteome towards a pre-disease state in our animal model. These results indicate cell-based therapies show promise in improving RV function after pressure overload through partial restoration of the disease-altered cardiac proteome.

Depletion by Hemodialysis of the Antioxidant Ergothioneine

Background: Hemodialysis may excessively remove valuable solutes. Untargeted metabolomics data from a prior study suggested that ergothioneine was depleted in the plasma of hemodialysis subjects. Ergothioneine is a dietary-derived solute with antioxidant properties. The presence of a highly specific ergothioneine uptake transporter suggests that it is valuable. Ergothioneine levels are high in tissues susceptible to oxidative stress, particularly erythrocytes. We compared erythrocyte and plasma ergothioneine levels in subjects receiving hemodialysis to those in subjects with advanced chronic kidney disease (CKD) and subjects without known kidney disease (controls). We further examined the extent to which indiscriminate removal by hemodialysis could contribute to ergothioneine depletion. Methods: Liquid chromatography tandem mass spectrometry with stable isotope dilution was used to measure the erythrocyte and plasma levels of ergothioneine in 12 control, 12 CKD, and 11 hemodialysis subjects. We also measured the urinary excretion of ergothioneine in control and CKD subjects, and the dialytic removal of ergothioneine in hemodialysis subjects. Results: Erythrocyte ergothioneine levels were markedly reduced in CKD and hemodialysis subjects. Erythrocyte levels in CKD subjects were on average 24% of the levels in control subjects and were even lower in hemodialysis subjects, averaging 8% of control subjects. Plasma ergothioneine levels were also reduced in CKD and hemodialysis subjects but to a lesser extent than the erythrocyte levels. Kidney tubular reabsorption of ergothioneine was avid. In contrast, hemodialysis cleared ergothioneine at a rate of 146±36 ml/min so that removal of ergothioneine by hemodialysis greatly exceeded the amount excreted in the urine in both CKD and control subjects. Conclusions: Ergothioneine, a potentially valuable antioxidant, is severely depleted in people maintained on hemodialysis. Future studies are required to assess the consequences of ergothioneine depletion.

Optimization, Validation, and Application of Cleanup-Coupled Liquid Chromatography–Tandem Mass Spectrometry for the Simultaneous Analyses of 35 Mycotoxins and Their Derivatives in Cereals

Mycotoxins occur singly or as co-contaminants and are primarily present in carbohydrate-rich foods such as cereals and cereal-based products. To effectively monitor mycotoxin co-contamination in cereals and cereal-based products, the simultaneous analysis of mycotoxins and their derivatives is required. Therefore, we coupled cleanup with LC-MS/MS for the rapid and robust quantitation of 35 analytes in wheat samples, including ergot alkaloids (EAs), which are rarely included in such analyses. To investigate the effects of different mycotoxin types on adsorbents, various dispersive solid-phase extraction sorbents were evaluated; a C18 end-capped sorbent exhibited the most effective cleanup performance. The method was validated by analyzing samples fortified with the mycotoxins at three concentration levels. The results exhibited high linearity, high recoveries, and repeatability. The methodology was applied for commercial cereal samples. The cereal samples were found to be 74% contaminated, and two samples measured levels of EAs at 609.63 μg/kg and 294.93 μg/kg, exceeding the limits defined by the EU for rye milling products. These findings highlight the validity of our novel method and the necessity of continuously monitoring mycotoxin levels in cereals to ensure food safety.

Age and sex effects of a validated LC-MS/MS method for the simultaneous quantification of testosterone, allopregnanolone, and its isomers in human serum.

Despite the great relevance of the neurosteroid allopregnanolone and related isomers to various health conditions, quantification typically involves immunoassay, which suffers from serious issues with cross-reactivity of closely related molecules. This article describes the development and partial validation of a liquid chromatography coupled with tandem mass spectrometry assay for the simultaneous quantification of allopregnanolone, pregnanolone, isopregnanolone, epi-allopregnanolone, and testosterone in the human serum of healthy males and females aged 5-85 years. 1-amino-4-methylpiperazine (AMP) was used as a derivatisation reagent to enhance the ionisation signal. Linearity was calculated at 0.99 with a lower limit of quantification of 10.08 pg/mL for allopregnanolone, along with a linearity of 0.98 and a lower limit of quantification of 42.32 pg/mL for testosterone. Application of the method showed sex and age effects across the lifespan for both allopregnanolone and testosterone, whereas a comparative immunoassay for allopregnanolone was not able to detect differences in the same samples. Our partial validation of this method should provide a new tool for researchers to discover the role of allopregnanolone and its isomers in human health, and how it compares to testosterone and sex hormones.

Metabolomics Reveals the Mechanism by Which Sodium Butyrate Promotes the Liver Pentose Phosphate Pathway and Fatty Acid Synthesis in Lactating Goats

This study aimed to explore the effects of sodium butyrate on liver metabolism in goats subjected to a high-concentrate diet. We randomly assigned twelve Saanen-lactating goats into two groups, one of which received a high-concentrate diet (concentrate: forage = 60:40, control group), while the other received the same basal diet supplemented with sodium butyrate (SB) (10 g/kg basal diet, SB group). Compared with the control diet, the SB diet considerably increased the milk fat percentage and content (p &lt; 0.05), with an increase of 0.67% in the milk fat content of the SB group. By employing a global metabolomics approach based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS), we identified 6748 ions in ESI+ mode and 3573 ions in ESI− mode after liver isolation from both groups. A total of twenty-three metabolites, including phospholipids, fatty acids, and ribose phosphate, were found to be dysregulated according to a search against the human metabolome database (HMDB). Pathway analysis revealed activation of the pentose phosphate pathway, glycerophospholipid metabolism, and unsaturated fatty acid synthesis. The SB diet also modulated the expression of key lipogenic enzymes, such as acetyl-CoA carboxylase (ACC) and stearoyl-CoA desaturase (SCD-1), which are downstream targets of the transcription factor sterol regulatory element-binding proteins-1c (SREBP-1c), inducing a significant upregulation (p &lt; 0.05). Furthermore, 6-phosphogluconate dehydrogenase (6PGDH) levels in the liver were elevated after the lactating goats were fed the SB diet (p &lt; 0.05). Our study reveals that the SB diet may offer substantial benefits in enhancing the milk quality of subacute ruminal acidosis (SARA) goats. This is accomplished by augmenting the activity of the liver pentose phosphate pathway and the process of de novo fatty acid synthesis in lactating goats.

Metabolomic Analysis of Specific Metabolites in Codonopsis pilosula Soil Under Different Stubble Conditions

To investigate the soil-specific metabolites of Codonopsis pilosula under different stubble management practices, this study analyzed differentially abundant metabolites in the rhizosphere soils of rotational (DS) and continuous (LS) cropping systems via liquid chromatography–tandem mass spectrometry (LC–MS/MS)-based metabolomic approaches. The results revealed that 66 metabolites, including amino acids and their derivatives, nucleic acids, alcohols, organic acids, amines, fatty acids, purines, and sugars, were significantly different (p &lt; 0.05) between the DS and LS groups. Under continuous cropping, the levels of amines, fatty acids, organic acids, and sugars in the rhizosphere soil were significantly greater (p &lt; 0.05) than those under rotational cropping, whereas the levels of amino acids and their derivatives, nucleic acids, and purines and pyrimidines were significantly lower (p &lt; 0.05). KEGG pathway enrichment analysis revealed that these differentially abundant metabolites were enriched in metabolic pathways such as amino acid metabolism (e.g., alanine, aspartate, and glutamate metabolism), carbon metabolism, the cAMP signaling pathway, ABC transporter proteins, phenylalanine metabolism, and the biosynthesis of plant secondary metabolites. These metabolic pathways were involved in osmoregulation, energy supply, and resilience in plants. In conclusion, inter-root soil metabolites in rotational and continuous cropping of Codonopsis pilosula were able to influence soil physicochemical properties and microbial populations by participating in various biological processes.

Proteomic identification of potential biomarkers for heat tolerance in Caracu beef cattle using high and low thermotolerant groups.

Heat stress has deleterious effects on physiological and performance traits in livestock. Within this context, using tropically adapted cattle breeds in pure herds or terminal crossbreeding schemes to explore heterosis is attractive for increasing animal production in warmer climate regions. This study aimed to identify biological processes, pathways, and potential biomarkers related to thermotolerance in Caracu, a tropically adapted beef cattle breed, by proteomic analysis of blood plasma. To achieve this goal, 61 bulls had their thermotolerance evaluated through a heat tolerance index. A subset of 14 extreme animals, including the seven most thermotolerant (HIGH group) and the seven least thermotolerant (LOW group), had their blood plasma samples used for proteomic analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The differentially regulated proteins detected between HIGH and LOW groups were used to perform functional enrichment analysis and a protein-protein interaction network analysis. A total of 217 proteins were detected only in the HIGH thermotolerant group and 51 only in the LOW thermotolerant group. In addition, 81 and 87 proteins had significantly higher and lower abundancies in the HIGH group, respectively. Regarding proteins with the highest absolute log-fold change values, we highlighted those encoded by DUSP5, IGFALS, ROCK2, RTN4, IRAG1, and NNT genes based on their functions. The functional enrichment analysis detected several biological processes, molecular functions, and pathways related to cellular responses to stress, immune system, complement system, and hemostasis in both HIGH and LOW groups, in addition to terms and pathways related to lipids and calcium only in the HIGH group. Protein-protein interaction (PPI) network revealed as important nodes many proteins with roles in response to stress, hemostasis, immune system, inflammation, and homeostasis. Additionally, proteins with high absolute log-fold change values and proteins detected as essential nodes by PPI analysis highlighted herein are potential biomarkers for thermotolerance, such as ADRA1A, APOA1, APOB, APOC3, C4BPA, CAT, CFB, CFH, CLU, CXADR, DNAJB1, DNAJC13, DUSP5, FGA, FGB, FGG, HBA, HBB, HP, HSPD1, IGFALS, IRAG1, KNG1, NNT, OSGIN1, PROC, PROS1, ROCK2, RTN4, RYR1, TGFB2, VLDLR, VTN, and VWF. Identifying potential biomarkers, molecular mechanisms and pathways that act in response to heat stress in tropically adapted beef cattle contributes to developing strategies to improve performance and welfare traits in livestock under tropical climates.

Measuring 15N and 13C Enrichment Levels in Sparsely Labeled Proteins Using High-Resolution and Tandem Mass Spectrometry.

Isotope labeling of both 15N and 13C in selected amino acids in a protein, known as sparse labeling, is an alternative to uniform labeling and is particularly useful for proteins that must be expressed using mammalian cells, including glycoproteins. High levels of enrichment in the selected amino acids enable multidimensional heteronuclear NMR measurements of glycoprotein three-dimensional structure. Mass spectrometry provides a means to quantify the degree of enrichment. Mass spectrometric measurements of tryptic peptides of a selectively labeled glycoprotein expressed in HEK293 cells revealed complicated isotope patterns which consisted of many overlapping isotope patterns from intermediately labeled peptides, which complicates the determination of the label incorporation. Two challenges are uncovered by these measurements. Metabolic scrambling of amino groups can reduce the 15N content of enriched amino acids or increase the 15N in nontarget amino acids. Also, undefined, unlabeled medium components may dilute the enrichment level of labeled amino acids. The impact of this unexpected metabolic scrambling was overcome by simulating isotope patterns for all isotope-labeled peptide states and generating linear combinations to fit to the data. This method has been used to determine the percent incorporation of 15N and 13C labels and has identified several metabolic scrambling effects that were previously undetected in NMR experiments. Ultrahigh mass resolution is also utilized to obtain isotopic fine structure, from which enrichment levels of 15N and 13C can be assigned unequivocally. Finally, tandem mass spectrometry can be used to confirm the location of heavy isotope labels in the peptides.

Autonomous Dissociation-type Selection for Glycoproteomics Using a Real-Time Library Search.

Tandem mass spectrometry (MS/MS) is the gold standard for intact glycopeptide identification, enabling peptide sequence elucidation and site-specific localization of glycan compositions. Beam-type collisional activation is generally sufficient for N-glycopeptides, while electron-driven dissociation is crucial for site localization in O-glycopeptides. Modern glycoproteomic methods often employ multiple dissociation techniques within a single LC-MS/MS analysis, but this approach frequently sacrifices sensitivity when analyzing multiple glycopeptide classes simultaneously. Here we explore the utility of intelligent data acquisition for glycoproteomics through real-time library searching (RTLS) to match oxonium ion patterns for on-the-fly selection of the appropriate dissociation method. By matching dissociation method with glycopeptide class, this autonomous dissociation-type selection (ADS) generates equivalent numbers of N-glycopeptide identifications relative to traditional beam-type collisional activation methods while also yielding comparable numbers of site-localized O-glycopeptide identifications relative to conventional electron transfer dissociation-based methods. The ADS approach represents a step forward in glycoproteomics throughput by enabling site-specific characterization of both N-and O-glycopeptides within the same LC-MS/MS acquisition.

Effect of dietary supplementation of yeast culture Saccharomyces cerevisiae in lactating female goats

This study was designed to investigate the effects of adding a novel yeast culture, Saccharomyces cerevisiae refermented sorghum distiller's dried grains with solubles (SSDDGS), to the diets of lactating female goats on lactation performance and lamb growth performance. We divided 10 lactating Dazu black goats of similar age, weight, and offspring into two groups: one fed a pelleted diet with 50 g/day SSDDGS (ET), and the other without SSDDGS as a control (EC) for 7 weeks. We monitor the weight changes of each goat and collect blood and milk samples from experimental ewes at specific times for hormone and milk composition determination. We use ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to detect metabolites in the serum of lactating ewes. Our results showed that SSDDGS supplementation significantly reduced female goats' average daily weight loss during weeks 2–4 of lactation and increased serum IGF-1 and prolactin levels at week 4 (p &amp;lt; 0.05). SSDDGS supplementation in early lactation significantly increased milk protein, lactose, and ash content (p &amp;lt; 0.05). UPLC-MS/MS analysis showed that SSDDGS changed the levels of 58 metabolites in the serum of lactating goats. These metabolites were mainly involved in the sohingolipid signaling pathway, and cysteine, methionine, and sphingolipid metabolism. In summary, Yeast culture SSDDGS reduced weight loss, enhanced milk quality, and modified metabolic profiles in early lactation goats, providing insight into the potential regulatory role and mechanism of yeast culture in lactation female goats.

Abstract 4138498: Sex Differences in Plasma Acylcarnitines in Patients with STEMI undergoing Primary PCI

Background: Rapid coronary reperfusion using primary PCI is the corner stone therapy for patients presenting with STEMI that restores blood flow and limits infarct size. But paradoxically, the reperfusion process itself can induce additional myocardial injury. Females have increased rates of cardiovascular death compared with males following MI, and it is unclear whether this is related to differences in presentation or reperfusion injury. Given these differences, we aim to better understand the sex differences in the lipidome shift post PCI. METHODS&amp;RESULTS: 126 patients(97 males, 29 females) undergoing PCI for STEMI in a tertiary centre underwent venous blood sampling and semi-targeted Liquid Chromatography Tandem Mass Spectrometry(LC/MS/MS) to determine 291 lipid species. Samples were taken pre-PCI(T0), and 2 hours post PCI(T1) with successful reperfusion. Each lipid class and species were compared between males and females at each time point using statistical analysis, to determine the similarities and differences in plasma lipidome shifts in ACS between sexes. Whilst most lipid classes decrease following reperfusion in STEMI (T0 vs T1), Acylcarnitines increase (20%, adjusted p=0.003) in both sexes. There is a clear sex difference with a greater increase in females (39% increase, adjusted p=0.03), as compared with males (13% increase, adjusted p=0.048). In both sexes this is primarily driven by OctadecanoylCarnitine (C8), which is a medium-chained acylcarnitine. Notably, there was no significant difference in C8 between the sexes in the control group, nor the pre-PCI group(adjusted p=0.48, at T0). At T0, total free fatty acids(FFA) and total phosphatidylinositol were significantly elevated in females compared with males(adjusted p=0.012, p=0.018 respectively). Conclusion: Our analysis suggests there are differences in lipidomics shift between males and females in response to myocardial reperfusion. The higher levels of circulating FFA in ischemic females pre-PCI(T0), followed by a parallel increase of acylcarnitine with reperfusion(T0vsT1), suggest differences between the sexes in myocardial metabolic response to reperfusion injury. C8 has been associated with elevated risk of cardiovascular death in stable CAD, but its clinical impact during reperfusion is still unknown. Detailed understanding of sex specific lipidomics shifts during reperfusion injury will allow us to better understand the mechanistic differences in clinical outcome between males and females.

Integrative Transcriptomic and Metabolomic Analysis Reveals Quinoa Leaf Response Mechanisms to Different Phosphorus Concentrations During Filling Stage

Quinoa is an annual self-pollinating plant rich in polyphenols, flavonoids, saponins, and amino acids; its protein balance closely aligns with the ideal recommendation set by the Food and Agriculture Organization. Therefore, quinoa is considered the most suitable “all-nutrient food”. Phosphorus fertilization plays an important role in restricting the growth and development of quinoa; however, the effects of phosphorus fertilizer on quinoa growth remain unclear. Therefore, we conducted metabolome and transcriptome analyses on quinoa leaves during the filling stage, subjecting plants to different doses of phosphorus fertilizer. Overall, phosphorus treatment exerted a significant impact on the phenotypic characteristics of quinoa. Specifically, through a combined analysis of ultra-performance liquid chromatography–tandem mass spectrometry and transcriptome analysis, we identified the alteration and regulation of specific metabolites and genes within flavonoid biosynthesis pathways; this comprehensive evaluation helped elucidate the response mechanism of quinoa leaves during the grouting stage under various phosphorus conditions. Ultimately, the results of this study provide a reference for the selection of quinoa cultivars that exhibit tolerance to low- or high-phosphorus stress; additionally, we offer a theoretical basis for the rational application of phosphorus fertilizer and the enhancement of phosphorus utilization efficiency.