PubMed · 4367649
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T N Chase. 1974. Serotonergic-dopaminergic interactions and extrapyramidal function.. https://pubmed.ncbi.nlm.nih.gov/4367649/
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Biogenic amines (BAs) are toxic metabolites that accumulate in fermented foods and pose significant food safety concerns. Although several lactic acid bacteria (LAB) have previously been reported to exhibit strain-specific BA-degrading phenotypes, the genetic determinants underlying these activities have remained largely uncharacterized. Here, we analyzed 8251 LAB genomes to validate BA-degrading phenotypes. We predicted five BA-associated genes, including two direct biogenic amine-degrading genes (BADGs), mco and patA, and three polyamine-modifying genes (PMGs), speG, paiA, and bltD. Among BADGs, mco was broadly distributed across LAB and strongly enriched across food-associated niches. patA, organized within a conserved potD-glnB-potABC-patA cassette, is a putative, functionally distinct BADG in LAB, revealing a nitrogen-responsive polyamine uptake-catabolism module. Phylogenomics, phylogenetic reconciliation, and synteny analysis established that all five genes entered the LAB through episodic horizontal gene transfer followed by lineage-specific fixation. GC compositional bias and mobile genetic element association further corroborated the horizontal origin of the two BADGs. Structural analysis confirmed the conservation of catalytic core residues of BADGs across LAB, indicating strong purifying selection. Phenotype-to-genotype correlation with experimentally reported LAB suggested mco as a reliable genomic predictor of degrading phenotype. Integration of degradation and biosynthetic profiles predicted multiple LAB species capable of both synthesizing and degrading BA, along with 1823 genomes with degradation potential but lacking detectable BA biosynthesis genes. This study provides the first large-scale genome framework linking BA-degrading phenotypes with their genetic determinants in LAB and offers a rational basis for selecting BA-detoxifying strains for fermented food applications.
Accurate detection of biogenic amines (BAs) in meat remains challenging due to their high structural similarity and co-occurrence. Herein, an Mn-N-C nanozyme was synthesized via a metal-organic framework confined pyrolysis strategy, possessing excellent oxidase (OXD)- and peroxidase (POD)-like activities. The dual enzyme-like activity showed Km values of 0.1584 mM (OXD) and 0.1498 mM (POD), respectively, in detection system. Leveraging these properties, a colorimetric sensor array was constructed, enabling the detection of four representative BAs within a concentration range of 2-10 ppm with 100% classification accuracy. In addition, a concentration independent recognition model based on an artificial neural network was developed to address signal nonlinearity interference in meat. The integrated system achieved accurate trace-level identification of BAs in perishable fish, pork, and chicken, demonstrating its applicability for early-stage BAs monitoring and quality deterioration warning during storage and transportation.
In two-dimensional capillary electrophoresis, a sample undergoes separation in the first dimension capillary by sieving electrophoresis. Fractions are periodically transferred across an interface into a second dimension capillary, where components are further resolved by micellar electrokinetic capillary electrophoresis. Previous instruments employed one pair of capillaries to analyze a single sample. We now report a multiplexed system that allows separation of five samples in parallel. Samples are injected into five first-dimension capillaries, fractions are transferred across an interface to 5 second-dimension capillaries, and analyte is detected by laser-induced fluorescence in a five-capillary sheath-flow cuvette. The instrument produces detection limits of 940 +/- 350 yoctomoles for 3-(2-furoyl)quinoline-2-carboxaldehyde labeled trypsin inhibitor in one-dimensional separation; detection limits degrade by a factor of 3.8 for two-dimensional separations. Two-dimensional capillary electrophoresis expression fingerprints were obtained from homogenates prepared from a lung cancer (A549) cell line, on the basis of capillary sieving electrophoresis (CSE) and micellar electrophoresis capillary chromatography (MECC). An average of 131 spots is resolved with signal-to-noise greater than 10. A Gaussian surface was fit to a set of 20 spots in each electropherogram. The mean spot width, expressed as standard deviation of the Gaussian function, was 2.3 +/- 0.7 transfers in the CSE dimension and 0.46 +/- 0.25 s in the MECC dimension. The standard deviation in spot position was 1.8 +/- 1.2 transfers in the CSE dimension and 0.88 +/- 0.55 s in the MECC dimension. Spot capacity was 300.