Search Results (117)

Microbial contamination of hatching eggs often leads to reduced hatchability and poor chick quality. As trimethylamine (TMA), a metabolite derived from dietary choline, has antimicrobial properties, increasing yolk TMA contents may increase bacterial resistance to eggs; however, the effects of TMA concentrations on chick quality remain unknown. Hence, this study was conducted to determine the effects of yolk TMA concentrations on the hatchability and chick quality of dwarf hens with different FMO3 genotypes. Hens (n = 140) were divided into control and experimental groups; the latter received choline chloride (2800 mg/kg) to elevate their yolk TMA concentrations. The TMA content, Pasgar score, hatchability, and post-hatching performance were evaluated. The results showed that choline supplementation significantly increased TMA concentrations in hens with AT and TT genotypes. Higher yolk TMA concentrations (≥4 µg/g) correlated with improved Pasgar scores and reduced abnormalities in vitality, navel, and yolk sac absorption. Hatchability peaked at 6.49 µg/g TMA, suggesting a threshold effect. Although the growth rate remained unaffected, chick mortality decreased in the high-TMA group. Therefore, moderate TMA concentrations can enhance egg antimicrobial defenses and improve reproductive performance. This strategy provides a biologically grounded alternative to traditional chemical disinfection in hatcheries. Full article

Background/Objectives: Coronary slow flow phenomenon (CSFP) is a cardiovascular condition characterized by delayed passage of contrast medium through the coronary arteries, predominantly affecting young male smokers admitted with acute coronary syndrome. Although over 80% of patients experience recurrent chest pain and more than 20% require readmission, the etiology of CSFP remains poorly understood. Given the emerging role of gut microbiome in cardiovascular diseases, this study investigates the microbial composition associated with CSFP. Methods: Stool samples were collected from patients diagnosed with CSFP and healthy control individuals. Microbiota profiling was performed using 16S rRNA sequencing. Taxonomic differences were evaluated to identify microbial markers potentially associated with CSFP. Results: The analysis revealed a notable enrichment of the genus Gemmiger and the species Anaerobutyricum in CSFP patients, specifically within the selenium metabolism pathway. This is of particular interest given the established link between selenium deficiency and heightened cardiovascular risk, suggesting a possible microbiome-mediated modulation of selenium bioavailability in CSFP pathophysiology. Moreover, a marked increase in taxa associated with the biosynthesis of trimethylamine (TMA), a proatherogenic metabolite implicated in the onset and progression of various cardiovascular disorders, was observed in the CSFP cohort, further supporting a potential mechanistic role of gut microbiota in the disease’s underlying etiology. Conclusions: Although statistical significance could not be established due to the limited sample size, the observed trends support the hypothesis that specific gut microbes and metabolic pathways, particularly those linked to selenium metabolism and TMA production, may serve as potential microbial indicators for CSFP. These preliminary findings warrant further investigation in larger cohorts. Full article

Background/Objectives: Trimethylamine (TMA), produced by gut microbiota, and its derivative trimethylamine N-oxide (TMAO) are both associated with cardiometabolic diseases. While the effects of high-fat diets (HFDs) and high-disaccharide diets (HDDs) on gut microbiota in the context of obesity have been well studied, their impact on TMA/TMAO production, particularly alongside physiological caloric intake, remains obscure. This study investigates how standard HFDs and HDDs alongside physiological caloric intake influence gut microbiota composition and TMA/TMAO production in rats. Methods: Sprague Dawley rats were fed one of three diets a standard diet, an HFD, or an HDD for 12 weeks, with chow availability adjusted by age to maintain physiological caloric intake. Gut bacterial diversity was analyzed using 16S rRNA gene sequencing, and metabolites were quantified via High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) in urine and plasma. Results: The HFD group had significantly higher urinary levels of TMA and TMAO compared to the control and HDD groups. Gut bacterial diversity in the HFD group was markedly reduced, displaying the lowest species richness and phylogenetic diversity among all the groups. Notably, Pasteurellaceae (within the order Pasteurellales) and S24-7 (within the order Bacteroidales) were positively correlated with TMAO levels. The demonstrated HDD group increased microbial diversity compared to both the control and HFD groups. Conclusions: A high-fat diet during controlled and physiological caloric intake increases TMA/TMAO production and reduces gut microbial diversity. This underscores the role of diet composition, beyond caloric excess, in shaping gut microbiota and the related cardiometabolic biomarkers. Full article

A ratiometric fluorescent film with high gas sensitivity and stability was developed using electrospinning technology for monitoring food spoilage. 5(6)-Carboxyfluorescein (5(6)-FAM) was used as the indicator, combined with the internal reference Rhodamine B (RHB), to establish a composite ratiometric fluorescent probe (FAM@RHB). The hydrophobic fluorescent films were fabricated by incorporating FAM@RHB probes into polyvinylidene fluoride (PVDF) at varying molar ratios through electrospinning. The FR-2 film with a 2:8 ratio of 5(6)-FAM to RHB exhibited the best performance, demonstrating excellent hydrophobicity with a water contact angle (WCA) of 113.45° and good color stability, with a ΔE value of 2.05 after 14 days of storage at 4 °C. Gas sensitivity tests indicated that FR-2 exhibited a limit of detection (LOD) of 0.54 μM for trimethylamine (TMA). In the application of monitoring the freshness of pork and beef at 4 °C, the fluorescence color of the FR-2 film significantly changed from orange–yellow to green, enabling the visual monitoring of meat freshness. Hence, this study provides a new approach for intelligent food packaging. Full article

Seafood, especially marine fish, is highly prone to spoilage during processing, transportation, and storage. It releases pungent trimethylamine (TMA) gas, which severely affects food quality and safety. Metal–oxide–semiconductor (MOS) gas sensors for TMA detection offer a rapid, convenient, and accurate method for assessing fish freshness. Indium oxide (In₂O₃) has shown potential as an effective sensing material for the detection of TMA. In this work, one-dimensional In₂O₃ nanowires with different grain sizes and levels of crystallinity were synthetized using the electrospinning technique and underwent different thermal calcination processes. Gas-sensing tests showed that the In₂O₃–3 °C/min–500 °C gas sensor exhibited an outstanding performance, including a high response (R_a/R_g = 47.0) to 100 ppm TMA, a short response time (6 s), a low limit of detection (LOD, 0.0392 ppm), and an excellent long-term stability. Furthermore, the sensor showed promising experimental results in monitoring the freshness of Larimichthys crocea (L. crocea). By analyzing the relationship between the grain size and crystallinity of the In₂O₃ samples, a mechanism for the enhanced gas-sensing performance was proposed. This work provides a novel strategy for designing and fabricating gas sensors for TMA detection and highlights their potential for broad applications in real-time fish freshness monitoring. Full article

Methylamines are present in numerous organisms and microorganisms capable of de novo trimethylamine (TMA) production are widely distributed, including microalgae. However, such compounds may hamper the application of microalgae biomass in commercially interesting products, such as food and feed products, due to the strong fishy smell. In the present study, several bacteria able to degrade TMA were isolated. Among them, a Staphylococcus saprophyticus strain was found particularly suitable to degrade TMA. After finding the best culture conditions, a bioprocess system was developed allowing the degradation of TMA from microalgae in a reactor by S. saprophyticus cells present in a second reactor without direct contact with media from both reactors. The system was found to be limited by TMA transfer through the gas phase, with the cells being able to degrade all available TMA. Full article

Insulin resistance (IR) is a risk factor for various diseases. Diet plays a crucial role in the development of IR. The high-protein diet (HPD) is gaining popularity for its weight control benefit. However, some types of protein can be metabolized by gut microbiota into trimethylamine (TMA), subsequently oxidized into trimethylamine N-oxide (TMAO) in the liver. However, the underlying mechanism of HPD-induced IR remains unclear. In this study, we firstly investigated whether the HPD can induce IR. Next, we examined liver function and the signaling pathways involved in IR. At last, we detected changes in the composition and function of gut microbiota, particularly concerning TMA production. Our results demonstrated that the HPD induces IR and liver injury, 41% higher TMA concentration than in the control group. Transcriptome results confirmed that insulin-related pathways were enriched in the HPD group, especially the Insrr gene, which regulates insulin action through its receptor, was downregulated. Disrupted gut microbiota, dominated by 65.0% of Firmicutes, which have high potential in TMA production. Moreover, several amino acid metabolism pathways closely linked to IR were enriched in the HPD group. These findings highlight the need for careful dietary management, as the HPD can induce IR and liver injury, with gut microbiota playing a key role in TMA production. Full article

Background/Objectives: Trimethylamine N-oxide (TMAO) is a gut microbiota-dependent metabolite considered as a risk metabolite for various non-communicable diseases. This study aims to identify differences in the gut microbiota composition and concentrations of TMAO and related metabolites in subjects with and without metabolic syndrome (MetS). Methods: Plasma samples were collected following an overnight fast on two occasions from subjects with (n = 12) and without (n = 21) MetS. Feces samples were collected on the day before the first blood sampling. The gut microbiota was profiled using 16S rRNA full-gene amplification sequencing. TMAO and related methylamines were quantified using UPLC-MSMS. The fasted plasma glucose, plasma lipid profile, and HbA1c were determined, and blood pressure, circumference, height, and weight were measured. Results: A divergent gut microbiota composition was observed in feces samples from both groups. In contrast to subjects without MetS, subjects with MetS had a reduced microbial diversity, with lower Blautia glucerasea and higher Ruminococcus torques—a pattern associated with (increased) inflammation. Trimethylamine (TMA)-producing bacteria were low in abundance across both groups. While plasma TMAO and related methylamines displayed no significant differences between both groups, L-carnitine was elevated (p = 0.0191) in subjects with MetS. A strong positive correlation was detected between TMAO and TMA (r = 0.439, p = 0.003), with a tendency to correlate with carnitine (r = 0.212, p = 0.087). Conclusions: Subjects with MetS were characterized by gut microbiota favoring inflammation-associated species but not TMA producers. This suggests that TMAO may not play a role in MetS subjects without overt comorbidities, e.g., CVD or T2D. The influence of the gut microbiota on early MetS is likely mediated through inflammatory mechanisms driven by specific bacterial shifts rather than TMAO production. Full article

The objective of the present study was to determine the effect of mixed plant extracts on chemical (pH, total volatile base nitrogen (TVB-N), trimethylamine nitrogen (TMA), thiobarbituric acid reactive substances (TBARS), biogenic amines, relative fatty acid composition) and microbiological quality indicators of vacuum-packed fish burgers stored at 0 ± 2 °C over 13 days. Three mixtures of common juniper by-product and blackberry leaves extracts (JB), Padina pavonica and prickly juniper needles extracts (PCJ), and blackberry leaves extract with catechin and vanillic (BCV) were tested. At the end of storage, TVB-N (15.38–20.03 mg/100 g) and TMA (10.64–15.63 mg/100 g) of burgers with extracts were significantly lower than those of the control group (22.77 mg TVB-N/100 g, 18.37 mg TMA/100 g). The TBARS values in the control burger reached 2.62 ± 0.02 µmol malondialdehyde (MDA)/100 g, while in burgers with extracts, final values were in the range of 0.62 ± 0.01 to 0.80 ± 0.02 µmol MDA/100 g. The extracts showed no effect on biogenic amine formation (tryptamine, putrescine, and cadaverine levels increased during the storage, being the lowest in BCV) or microbial counts, with the exception of the Pseudomonas sp. counts that were significantly lower in JB and PCJ in comparison to the control, reaching 4.1, 4.1, and 5.0 log CFU/g in JB, PCJ, and control, respectively. Full article

Eulerian observations of chemical species at fixed positions in a flow field are known to violate conservation laws, while observations tracking moving air parcels are practically unfeasible. Eulerian observations often cause positive correlations between the reactants and products in the atmosphere, which are frequently misinterpreted as evidence of the related chemical conversion. This dilemma has motivated innovative trials. The perturbation technique, widely used in mathematical and physical studies, offers a potential solution. Combining Eulerian observations with perturbation techniques may compensate for this weakness, making this approach particularly valuable for studying the gas–aerosol partitioning of semi-volatile particulate species in ambient air. As an example, we examined this combination through an adiabatic-expansion-induced perturbation study of the gas–aerosol partitioning of dimethylamine (DMA) and trimethylamine (TMA) in ambient air. Eulerian observations of chemical species in size-segregated atmospheric particles ranging from 10 μm to 0.056 μm, coupled with downstream adiabatic-expansion-induced perturbation observations, were performed in coastal and marine atmospheres using a commercial sampler (Nano-MOUDI-II, MSP, Shoreview, MN, USA), followed by an offline chemical analysis. The results revealed that particulate DMA generally tended to evaporate in ambient air during the observational periods, while enhanced adiabatic-expansion-induced perturbations occasionally led to the co-formation of DMAHNO₃ and NH₄NO₃. However, gaseous TMA apparently underwent gas–particle condensation to reach equilibrium in ambient air, with adiabatic-expansion-induced perturbation resulting in the formation of non-ionized TMA particulates. The thermodynamic analysis further supported that the observed particulate TMA was primarily determined by the equilibrium of gaseous TMA with non-ionized particulate TMA rather than ionic TMAH⁺. Full article

Trimethylamine N-oxide (TMAO) is an endogenous osmolyte produced by enzymatic reactions starting in the human gut, where microbiota release trimethylamine (TMA) from foods, and ending in the liver, where TMA is oxidized to TMAO by flavin-containing monooxygenase 3 (FMO3). While physiological concentrations of TMAO help proteins preserve their folding, high levels of this metabolite are harmful and promote oxidative stress, inflammation, and atherosclerosis. In humans, elevated levels of circulating TMAO predispose individuals to cardiovascular diseases and chronic kidney disease and increase mortality risk, especially in the elderly. How TMAO exerts its negative effects has been only partially elucidated. In hypertensive rats, the eNOS substrate L-arginine and Taurisolo^®, a nutraceutical endowed with TMAO-reducing activity, act synergistically to reduce arterial blood pressure. Here, we investigate the molecular mechanisms underpinning this synergism and prove that TMAO, the target of Taurisolo^®, acts as direct inhibitor of endothelial nitric oxide synthase (eNOS) and competes with L-arginine at its catalytic site, ultimately inhibiting NO production and acetylcholine (Ach)-induced relaxation in murine aortas. Full article

Methylamines, including monomethylamine (MMA), dimethylamine (DMA), and trimethylamine (TMA), are essential industrial intermediates. However, traditional catalysts suffer from poor product selectivity and are being phased out due to shifting market demands. Zeolites have emerged as promising alternatives due to their high activity and superior selectivity. Large- and medium-pore zeolites require modifications to enhance MMA- and DMA-selectivity by reducing pore size, whereas small-pore zeolites inherently exhibit high selectivity for MMA and DMA without modification. However, their high production costs have hindered large-scale commercialization. Research efforts are now focused on developing cost-effective catalysts to shift methylamine synthesis from equilibrium-driven (balancing) to selective (unbalancing) processes. This review explores the performance of zeolite-based catalysts in methylamine synthesis, highlighting key factors influencing selectivity. Additionally, it examines the challenges associated with small-pore zeolites and discusses strategies to enhance their application. Full article

The storage temperature is important for maintaining the quality of raw fish meat. The characteristics of ordinary muscle (OM) and dark muscle (DM) differ. This study aimed to clarify the effects of storage temperature (refrigeration, ice storage, and super-chilled (SC) storage) on the bacterial flora and quality (biochemical changes, volatile organic compounds (VOCs), and off-flavor development) of both muscles of yellowtail (Seriola quinqueradiata). SC storage effectively extended the shelf life of the dorsal part of ordinary muscle (OM) and DM by reducing bacterial proliferation, VOC changes, and off-flavor formation. However, their effects on the inhibition of trimethylamine (TMA) accumulation and lipid oxidation are limited. (E,E)-2,4-octadienal and (E,E)-3,5-octadien-2-one were identified as candidate markers of OM quality deterioration, whereas 1-hexanol was identified as a potential marker for DM. Alcohols, esters, and ketones are potential spoilage indicators of yellowtail muscles (OM and DM). Pseudomonas was the dominant spoilage bacterium in OM and DM across all storage conditions, with Acinetobacter, Brochothrix, and Shewanella appearing in later storage stages. These findings highlight the importance of storage at lower temperatures and understanding the dynamics of spoilage-causing bacteria and changes in VOCs in raw fish meat (OM and DM) to prevent spoilage and maintain meat quality. Full article

Trimethylamine-N-oxide (TMAO) is associated with various chronic diseases. TMAO is a downstream oxidative metabolite of trimethylamine (TMA) that is generated by the gut microbiota from dietary choline, carnitine, and betaine. Current analytical methods predominantly target TMAO only, due to the challenge of efficiently extracting and quantifying TMA. The present study demonstrates a simple and rapid UPLC–MRM–MS method for concurrent quantification of TMAO, TMA, and related precursors (choline, betaine, and various carnitines) following a methanol extraction from plasma and derivatization using iodoacetonitrile (IACN). Pure methanol resulted in a higher extractability of TMA (up to two-fold) compared to both pure acetonitrile and various methanol/acetonitrile mixtures. The quantification method showed high linearity within the tested range of 0.0625–100 μmol/L (determination coefficient > 0.999) and an intra- (n = 3) and inter-day (n = 9) precision of 2–8% along with an average recovery of above 94% for all metabolites (TMAO, TMA, choline, betaine, L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine). The method’s applicability was confirmed through a comparison of TMAO and its precursor concentrations in plasma samples of overnight-fasted subjects with (n = 12) and without (n = 21) metabolic syndrome. Full article

Common bunt disease in wheat is a serious threat to crops and food security. Rapid assessments of its severity are essential for effective management. The electronic nose (e-nose) system is used to capture volatile organic compounds (VOCs), particularly trimethylamine (TMA), which serves as a key marker of common bunt disease in wheat. In this paper, the GFNN (gas feature neural network) model is proposed for detecting VOCs from the e-nose system, providing a lightweight and efficient approach for assessing disease severity. Multiscale convolution is employed to extract both global and local features from gas data, and three attention mechanisms are used to focus on important features. GFNN achieves 98.76% accuracy, 98.79% precision, 98.77% recall, and an F1-score of 98.75%, with only 0.04 million parameters and 0.42 million floating-point operations per second (FLOPS). Compared to traditional and current deep learning models, GFNN demonstrates superior performance, particularly in small-sample-size scenarios. It significantly improves the deep learning performance of the model in extracting key gas features. This study offers a practical, rapid, and cost-effective method for monitoring and managing common bunt disease in wheat, enhancing crop protection and food security. Full article