Semi-rational evolution of ω-transaminase from Aspergillus terreus for enhancing the thermostability / 生物工程学报

ω-transaminase (ω-TA) is a natural biocatalyst that has good application potential in the synthesis of chiral amines. However, the poor stability and low activity of ω-TA in the process of catalyzing unnatural substrates greatly hampers its application. To overcome these shortcomings, the thermostability of (R)-ω-TA (AtTA) from Aspergillus terreus was engineered by combining molecular dynamics simulation assisted computer-aided design with random and combinatorial mutation. An optimal mutant AtTA-E104D/A246V/R266Q (M3) with synchronously enhanced thermostability and activity was obtained. Compared with the wild- type (WT) enzyme, the half-life t1/2 (35 ℃) of M3 was prolonged by 4.8-time (from 17.8 min to 102.7 min), and the half deactivation temperature (T1050) was increased from 38.1 ℃ to 40.3 ℃. The catalytic efficiencies toward pyruvate and 1-(R)-phenylethylamine of M3 were 1.59- and 1.56-fold that of WT. Molecular dynamics simulation and molecular docking showed that the reinforced stability of α-helix caused by the increase of hydrogen bond and hydrophobic interaction in molecules was the main reason for the improvement of enzyme thermostability. The enhanced hydrogen bond of substrate with surrounding amino acid residues and the enlarged substrate binding pocket contributed to the increased catalytic efficiency of M3. Substrate spectrum analysis revealed that the catalytic performance of M3 on 11 aromatic ketones were higher than that of WT, which further showed the application potential of M3 in the synthesis of chiral amines.

Ultrasensitive quantification of trace amines based on N-phosphorylation labeling chip 2D LC-QQQ/MS / 药物分析学报

Trace amines(TAs)are metabolically related to catecholamine and associated with cancer and neuro-logical disorders.Comprehensive measurement of TAs is essential for understanding pathological pro-cesses and providing proper drug intervention.However,the trace amounts and chemical instability of TAs challenge quantification.Here,diisopropyl phosphite coupled with chip two-dimensional(2D)liquid chromatography tandem triple-quadrupole mass spectrometry(LC-QQQ/MS)was developed to simul-taneously determine TAs and associated metabolites.The results showed that the sensitivities of TAs increased up to 5520 times compared with those using nonderivatized LC-QQQ/MS.This sensitive method was utilized to investigate their alterations in hepatoma cells after treatment with sorafenib.The significantly altered TAs and associated metabolites suggested that phenylalanine and tyrosine metabolic pathways were related to sorafenib treatment in Hep3B cells.This sensitive method has great potential to elucidate the mechanism and diagnose diseases considering that an increasing number of physiological functions of TAs have been discovered in recent decades.

Fusion expression with catalase improves the stability of multicopper oxidase and its efficiency in degrading biogenic amines / 生物工程学报

Some enzymes belonging to the multicopper oxidase (MCO) family can degrade the hazardous biogenic amine (BA) present in food. However, the oxidation of MCO in the process of degrading BAs may reduce its activity and stability, resulting in decreased catalytic efficiency. In this work, an MCO from Lactobacillus fermentum (MCOF) was fused with a Bacillus subtilis catalase (CAT) using different strategies and the fusion enzymes were respectively expressed in Escherichia coli BL21(DE3). The tolerance of eight fused MCOFs to H2O2 increased by 51%-68%, and the stability of CAT&MCOF increased by 17%, compared to the wild type MCOF. Using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) as a substrate, the substrate affinity (Km), the catalytic efficiency (kcat/Km) and the molar specific activity of CAT&MCOF increased by 1.0-fold, 1.7-fold and 1.2-fold than those of MCOF, respectively. The stability of CAT&MCOF under acidic conditions (pH 2.5-4.5) and moderate temperatures (35-55 °C) also improved. Moreover, the degradation rates of putrescine, cadaverine and histamine catalyzed by CAT&MCOF reached 31.7%, 36.0% and 57.8%, respectively, which increased by 132.5%, 45.7% and 38.9% compared to that of MCOF. The improvement on the stability and catalytic efficiency of MCOF by fusion expression with CAT provides a good example for improving the applicability of enzymes through molecular modifications.

Celastrus paniculatus oil ameliorates synaptic plasticity in a rat model of attention deficit hyperactivity disorder

Objective: To explore the effect and mechanism of action of Celastrus paniculatus oil on the treatment of perinatal rats with attention deficit hyperactivity disorder. Methods: In the perinatal stage, the rats were either isolated or administered with lead acetate to establish an animal model of attention deficit hyperactivity disorder. Atomoxetine served as the reference standard. Animals' behaviours were assessed through Y-maze, novel object preference, fear conditioning and residentintruder aggression tests. Oxidative stress parameters, bioamine concentration (dopamine, noradrenaline and 5-hydroxytryptamine), nerve growth factor, interleukin-6, nuclear factor-κB, and tumour necrosis factor (TNF)-α were estimated. Synaptophysin immunohistochemical assay was performed. Results: Celastrus paniculatus oil significantly improved behavioural parameters in Y maze, novel object preference, discrimination index, fear conditioning and resident intruder aggressive tests. The treatment groups showed a decrease in malondialdehyde level. Changes in the levels of dopamine, noradrenaline, and serotonin were restored by Celastrus paniculatus oil. Celastrus paniculatus oil increased nerve growth factor and decreased interleukin-6, nuclear factor-κB, and TNF-α. Synaptophysin immunoreactivity was also improved by Celastrus paniculatus oil with alleviated reactive gliosis, degeneration, and vascular proliferation. Conclusions: This research shows the therapeutic potential of Celastrus paniculatus oil for the treatment of attention deficit hyperactivity disorder.

Development of a rapid GC-FID method to simultaneously determine triethylamine,diisopropylamine,and 1,1,3,3-tetramethylguanidine residues in an active pharmaceutical ingredient / 药物分析学报

A rapid GC-FID method was developed to simultaneously determine residual levels of triethylamine(TEA),1,1,3,3-tetramethylguanidine(TMG),and diisopropylamine(DIPA)in the synthetic route of an active pharmaceutical ingredient(API).Due to the severe absorption of amines on GC stationary phases,GC columns with various stationary phases were evaluated for optimal peak shape and reproducibility.The final conditions used the Agilent CP-Volamine column to resolve the three amines in 12 min.Various inlet liners were also screened to further improve the sensitivity of the analysis.The Restek Siltek? liner was selected to achieve the desired detectability for the method.The quantitation limits were 4,3,and 4 μg/mL for TEA,DIPA,and TMG in the presence of API,respectively.All three amines showed good linearity(r＞0.999)and recoveries(＞90％)over the concentration range of 3 to 16 μg/mL.The testing of residual amines was initially performed at the penultimate stage of the synthesis.However,this work demonstrates that TMG can act as a proton sponge to react with salicylic acid,the counter ion of the penultimate,to form a volatile component that elutes at a different retention time.Consequently,in the final method,these three amines were monitored in the final API to circumvent the matrix interference.Key parameters of the method were qualified per method validation requirements in ICH guidelines.The method was successfully applied for batch testing during development and implemented as an in-process control procedure at manufacturing sites.

Celastrus paniculatus oil ameliorates synaptic plasticity in a rat model of attention deficit hyperactivity disorder

Objective: To explore the effect and mechanism of action of Celastrus paniculatus oil on the treatment of perinatal rats with attention deficit hyperactivity disorder. Methods: In the perinatal stage, the rats were either isolated or administered with lead acetate to establish an animal model of attention deficit hyperactivity disorder. Atomoxetine served as the reference standard. Animals' behaviours were assessed through Y-maze, novel object preference, fear conditioning and resident-intruder aggression tests. Oxidative stress parameters, bioamine concentration (dopamine, noradrenaline and 5-hydroxytryptamine), nerve growth factor, interleukin-6, nuclear factor-κB, and tumour necrosis factor (TNF)-α were estimated. Synaptophysin immunohistochemical assay was performed. Results: Celastrus paniculatus oil significantly improved behavioural parameters in Y maze, novel object preference, discrimination index, fear conditioning and resident intruder aggressive tests. The treatment groups showed a decrease in malondialdehyde level. Changes in the levels of dopamine, noradrenaline, and serotonin were restored by Celastrus paniculatus oil. Celastrus paniculatus oil increased nerve growth factor and decreased interleukin-6, nuclear factor-κB, and TNF-α. Synaptophysin immunoreactivity was also improved by Celastrus paniculatus oil with alleviated reactive gliosis, degeneration, and vascular proliferation. Conclusions: This research shows the therapeutic potential of Celastrus paniculatus oil for the treatment of attention deficit hyperactivity disorder.

Association Between Heterocyclic Amines Intake and Colorectal Cancer: A Dose-response Meta-analysis / 胃肠病学

Background: The intake of red meat and processed meat will increase the risk of colorectal cancer. Heterocyclic amines (HCAs), the intermediate mutagen in the processing of meat food, may be a potential risk factor for meat food to cause cancer. Aims: To investigate the association between HCAs intake and colorectal cancer, thereby providing a basis for prevention of colorectal cancer. Methods: Case-control and cohort studies concerning the association between HCAs intake and colorectal cancer were retrieved from PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wanfang and CQVIP databases. The literature was screened according to the inclusion and exclusion criteria. Meta-analysis was conducted by Stata 12.1 software. Results: A total of 17 studies involving 18 295 colorectal cancer patients were included, of which 14 were case-control studies and 3 were cohort studies. MeIQx intake could increase the risk of colorectal cancer (OR=1.16, 95% CI: 1.01-1.32, P=0.032), DiMeIQx intake (OR=1.20, 95% CI: 1.01-1.43, P=0.045), MeIQx intake (OR=1.24, 95% CI: 1.03-1.50, P=0.023) could increase the risk of colon cancer. No association between PhIP, HCAs and colorectal cancer, colon cancer, or rectal cancer was found. No dose-response relationship between DiMeIQx, MeIQx, PhIP, HCAs and colorectal cancer was found. Conclusions: MeIQx intake may increase the risk of colorectal cancer, DiMeIQx, MeIQx intake may increase the risk of colon cancer, and no dose-response relationship between HCAs intake and colorectal cancer was found.

Comparative study on chemical constituents of Cervi Cornu Pantotrichum in different forms of Cervus nipport / 中草药

Objective: In order to study the differences in chemical constituents of Cervi Cornu Pantotrichum in different forms of Cervus nipport. Methods: The content of polysaccharides, crude protein, amino acids, collagen, fatty acids, mineral elements, biogenic amines, nucleosides, and chondroitin sulfate composition of Cervi Cornu Pantotrichum in different forms of C. nipport was determined and compared by using UV spectrophotometer, Dumas azotometer, automatic amino acid analyzer, UPLC, HPLC, gas chromatograph, inductively coupled plasma mass spectrometer and atomic fluorescence photometer. Principal component analysis was used to evaluate the quality of Cervi Cornu Pantotrichum. Results: The content of polysaccharide, crude protein, amino acid, collagen, fatty acid, mineral element, biogenic amine, nucleoside and chondroitin sulfate in one-branched velvet antler was 8.40 mg/g, 44.82%, 42.24%, 23.23%, 6 234.69 mg/kg, 145.69 mg/g, 55.12 mg/kg, 2 271.87 mg/kg, and 0.74 mg/g, respectively; The content in two-branched velvet antler was 8.14 mg/g, 52.12%, 48.57%, 21.50%, 8 684.27 mg/kg, 126.40 mg/g, 76.14 mg/kg, 3 438.37 mg/kg, and 1.94 mg/g, respectively; The content in three-branched velvet antler was 8.64 mg/g, 51.86%, 45.49%, 22.31%, 9 100.78 mg/kg, 138.36 mg/g, 70.75 mg/kg, 2 507.82 mg/kg, and 1.84 mg/g, respectively. Conclusion: The chemical composition of Cervi Cornu Pantotrichum in different forms of C. nipport was different. The results of principal component analysis showed that the quality of the two-branched velvet antler was the best, the three-branched velvet antler was the second, the one-branched velvet antler was the worst. This study provides a reference for the quality evaluation and grading standards of different forms of Cervi Cornu Pantotrichum.

Expression and characterization of a multicopper oxidase from Lactobacillus fermentum / 生物工程学报

Biogenic amines (BAs) are low molecular weight organic compounds that present in fermented foods. Large amount of ingested biogenic amines can cause allergy or significant symptoms. Reduction of BAs by enzymatic reaction in fermented foods is one of the most efficient methods for removal of biohazard compounds and assurance food safety. In this study, the multicopper oxidase (MCO) gene in the genome of Lactobacillus fermentum was successfully cloned in Escherichia coli BL21 and expressed at 484 U/L. The recombinant MCO was purified by the immobilized metal affinity chromatography method. The optimal reaction temperature and pH for this enzyme was detected to be 50 °C and 3.5. The Km and Vmax values of the recombinant MCO was determined to be 1.30 mmol/L and 7.67×10⁻² mmol/(L·min). Moreover, this MCO dramatically degrades histamine and tyramine by 51.6% and 40.9%, and can degrade other BAs including tryptamine, phenylethylamine, putrescine, cadaverine and spermidine, and was found to be tolerant to 18% (W/V) NaCl. The recombinant MCO is also capable of degrading BAs in soy sauce. The degradation rate of total BAs in soy sauce reaches 10.6% though a relatively low level of enzyme (500 U/L) is used. Multicopper oxidase has the potential to degrade biogenic amines in fermented foods, which lays a foundation for the further application of this kind of food enzymes.

Biofiltration of trimethylamine in biotrickling filter inoculated with Aminobacter aminovorans

Background: Trimethylamine (TMA) is the main responsible for the odor associated with rotting fish and other annoying odors generated in many industrial activities. Biofiltration has proved to be efficient for treating odorous gaseous emissions. The main objective of this work was to determine the removal capacity of TMA of a biotrickling filter inoculated with Aminobacter aminovorans and to evaluate the effect of H2S on its performance. Results: The maximumspecific growth rate ofA. aminovorans in a liquid culture was 0.15 h -1 , witha TMAto biomass yield of 0.10 (g g -1) and a specific consumption rate of 0.062 g·g-1·h-1 . The initial specific consumption rate of TMA was highly influenced by the presence of H2S in liquid culture at concentrations of 20 and 69 ppm in heading space oftheflasks.ABTF inoculatedwithA. aminovorans showedremoval efficiencieshigher than98%ina range ofloading rate of 0.2 to 8 g·m-3·h-1 at empty bed residence time (EBRT) of 85 and 180 s. No effect on the elimination capacity and efficiency was detected when H2S was added at 20 and 50 ppm to the inlet gaseous emission, though the fraction of A. aminovorans measured by qPCR in the biofilm decreased. Conclusions:Abiotrickling filter inoculated with A. aminovorans can remove efficiently the TMA in a gaseous stream. The elimination capacity of TMA can be negatively affected by H2S, but its effect is not notorious when it is forming part of a biofilm, due to its high specific consumption rate of TMA.

Potential biogenic amine-producing bacteria in ripened cheeses

This study aimed to determine which of the eight cheese varieties (Prato, Standard Minas, Gorgonzola-, Moleson-, Raclette-,Gruyère-, Sbrinz- and Reblochon-types) prepared at a dairy processing plant in the state of Rio de Janeiro had higher concentration of biogenic amines (BA) (putrescine, cadaverine, yramine, histamine, spermidine and spermine), to detect which BA were produced at higher oncentrations and to determine if the presence of Enterobacteriaceae, biogenic amine producing bacteria (BAPB) or physical-chemical parameters (pH, titratable acidity, fat, moisture, total solids, protein, ash and chloride) ould be correlated with BA production in the eight matured cheese varieties. Moleson-type cheese (72.50 mg.Kg-1) followed by Standard Minas (107.00mg.Kg-1) showed the lowest levels of biogenic amines. Prato (699.29 mg.Kg-1) and Gorgonzola-type (936.37 mg.Kg-1) cheeses contained larger amounts of BA. Concentrations of tyramine exceeded the maximum permissible limit in all varieties of cheese. Although the presence of potentially BA-producing bacteria was confirmed in all samples of cheese, there was no correlation with BA content produced in cheeses. Gorgonzola-type cheese showed a positive correlation with the amount of BA in the isolates. Gorgonzola-type, Sbrinz-type and Prato cheeses seem to require greater care in monitoring the presence of biogenic amines, particularly because tyramine reached the highest levels in these varieties. Regardless of the analysed cheese, physical and chemical parameters did not affect the amount of BA produced. An assessment of the capacity to produce biogenic amines should be included as a selection criterion for starter cultures for ripened cheeses.

Biogenic amines and mycotoxins concentrations in baled silage from organic and conventional farms / Concentrações de aminas biogênicas e micotoxinas em silagem embalada de fazendas orgânicas e convencionais

The aim of the current study was to investigate biogenic amines and mycotoxins concentrations in baled silage (mainly Poaceae family grasses) prepared in organic and conventional farms and to relate these parameters to fermentative parameters. The mean dry matter (DM) content was 364.10±93.31 and 424.70±95.93g/kg in the silage from organic and conventional farms respectively. The silage samples from organic farms had 17.00% higher (P≤ 0.05) tyramine (TY) than the silage from conventional farms. Conventional farm samples were characterized by 46.00% higher histamine (HIS) (P≤ 0.05), 9.80% higher putrescine (PUT) (P≤ 0.05), 17.30% higher cadaverine (CAD) (P≤ 0.05). Aflatoxins (AFL) (total) and zearalenone (ZEN), T-2/HT-2 concentrations were higher respectively 16.00% (P≤ 0.05) and 13.40% (P≤ 0.05), 1.80% (P≤ 0.05) in the silage prepared in organic farms. Deoxynivalenol (DON) concentration was higher 42.40% (P≤ 0.05) in silage from conventional farms. Volatile fatty acids (VFA), lactic acid, ethanol, pH and ammonia nitrogen showed that the silage samples from organic and conventional farms were of good quality. Our study suggests differences in biogenic amine formation or mycotoxins content in silage from organic and conventional farming, but, overall, the measured values are too low to be relevant for animal health. Furthermore, these differences might as well be due to the difference in dry matter content and plant maturity between the organic and conventional silage samples.(AU)

O objetivo do presente estudo foi investigar concentrações de aminas biogênicas micotoxinas em silagem embalada (principalmente gramíneas da família Poaceae) preparada em fazendas orgânicas e convencionais e relacionar esses parâmetros a parâmetros fermentativos. A massa seca média (MS) foi 364,10±93,31 e 424,70±95,93g/kg na silagem de fazendas orgânicas e convencionais, respectivamente. As amostras de silagem de fazendas orgânicas tinham 17% a mais de tyramina (TY) (p≤ 0,05) que as de fazendas convencionais. As amostras de fazendas convencionais foram caracterizadas por histamina (HIS) 46,00% mais alta (P≤ 0,05), 9,80% putrecina (PUT) mais alta (P≤ 0,05), 17,30% de cadaverina (CAD) mais alta (P≤ 0,05). Aflatoxnas (AFL) (total) e zearalenone (ZEN), T-2/HT-2 tinham concentrações mais altas em respectivamente 16,00% (P≤ 0,05) e 13,40% (P≤ 0,05), 1,80% (P≤ 0,05) na silagem preparada em fazendas orgânicas. Deoxinivalenol (DON) tinha concentração mais alta 42,40% (P≤ 0,05) na silagem de fazendas convencionais. Ácidos graxos voláteis (AGV), ácido lático, etanol, pH e nitrogênio de amônia mostraram que as amostras de silagem de fazendas orgânicas e convencionais tinham boa qualidade. Nosso estudo sugere diferenças na formação biogênica de amônia ou micotoxinas em silagem de fazendas orgânicas ou convencionais mas, em geral, os valores medidos foram muito baixos para serem relevantes à saúde animal. Ademais, essas diferenças podem ser devido à diferença na matéria sólida e maturidade da planta entre as amostras de silagem orgânica e convencional.(AU)

Determination of Amines in Particulate Matter by Gas Chromatography-Mass Spectrometry / 分析化学

A method was developed for determination of thirteen amines including seven aliphatic amines, two heterocyclic amines and four aromatic amines in atmospheric particulate matter (PM) by gas chromatography-mass spectrometry (GC-MS). Samples were ultrasonically extracted with ultra-pure water and derivatized with benzenesulfonyl chloride (BSC) under alkaline conditions. The derivatives were extracted with dichloromethane and then detected by GC-MS using DB-5MS chromatographic column. The method detection limit (S/N=3) and quantitation limit (S/N=10) were 0.00008-0.017 μg/mL and 0.00026-0.0565 μg/mL respectively, and the correlation coefficients were 0.9903-0.9996, which indicated that the standard curve had good linear correlation. In addition, the relative standard deviation was less than 30％ and the average recovery was 54.4％-159.7％ except for methylamine and benzylamine at spiked level of 1.0 μg/mL, showing high precision and accuracy. 9 kinds of amines were detected in the PM2.5 samples collected in Guangzhou city by this method, among which dimethylamine and butylamine accounted for 90％ of the total nine amines, which indicated that they were primary amines in PM2.5; while propylamine exhibited the lowest level in PM2.5 with the concentration less than 1.0 ng/m3.

Deletion of a dynamic surface loop improves thermostability of (R)-selective amine transaminase from Aspergillus terreus / 生物工程学报

Chiral amines are important building blocks for the synthesis of pharmaceutical products and fine chemicals. Highly stereoselective synthesis of chiral amines compounds through asymmetric amination has attracted more and more attention. ω-transaminases (ω-TAs) are a promising class of natural biocatalysts which provide an efficient and environment-friendly access to production of chiral amines with stringent enantioselectivity and excellent catalytic efficiency. Compared with (S)-ω-TA, the research focused on (R)-ω-TA was relatively less. However, increasing demand for chiral (R)-amines as pharmaceutical intermediates has rendered industrial applications of (R)-ω-TA more attractive. Improving the thermostability of (R)-ω-TA with potential biotechnological application will facilitate the preparation of chiral amines. In this study, the dynamic surface loop with higher B-factor from Aspergillus terreus (R)-ω-TA was predicted by two computer softwares (PyMOL and YASARA). Then mutant enzymes were obtained by deleting amino acid residues of a dynamic surface loop using site-directed mutagenesis. The results showed that the best two mutants R131del and P132-E133del improved thermostability by 2.6 ℃ and 0.9 ℃ in T₅₀¹⁰ (41.1 ℃ and 39.4 ℃, respectively), and 2.2-fold and 1.5-fold in half-life (t1/2) at 40 ℃ (15.0 min and 10.0 min, respectively), compared to that of wild type. Furtherly, the thermostability mechanism of the mutant enzymes was investigated by molecular dynamics (MD) simulation and intermolecular interaction analysis. R131del in the loop region has lower root mean square fluctuation (RMSF) than the wild type at 400 K for 10 ns, and mutant enzyme P132-E133del increases four hydrogen bonds in the loop region. In this study, we obtain two stability-increased mutants of (R)-ω-TA from A. terreus by deleting its dynamic surface loop and also provide methodological guidance for the use of rational design to enhance the thermal stability of other enzymes.

Effect of Different Cooking Methods on Histamine Levels in Selected Foods

BACKGROUND: Histamine in food is known to cause food poisoning and allergic reactions. We usually ingest histamine in cooked food, but there are few studies about the influence of cooking method on the histamine level. OBJECTIVE: The purpose of this study was to determine the influence of cooking methods on the concentration of histamine in foods. METHODS: The foods chosen were those kinds consumed frequently and cooked by grilling, boiling, and frying. The histamine level of the food was measured using enzyme-linked immunosorbent assay. RESULTS: Grilled seafood had higher histamine levels than raw or boiled seafood. For meat, grilling increased the histamine level, whereas boiling decreased it. For eggs, there was not much difference in histamine level according to cooking method. Fried vegetables had higher histamine levels than raw vegetables. And fermented foods didn't show much difference in histamine level after being boiled. CONCLUSION: The histamine level in food has changed according to the cooking method used to prepare it. Frying and grilling increased histamine level in foods, whereas boiling had little influence or even decreased it. The boiling method might be helpful to control the effect of histamine in histamine-sensitive or susceptible patients, compared with frying and grilling.

Highly Sensitive Detection of Spermine Based on Fluorescence Quenching of Gold Nanoclusters / 分析化学

A new type of fluorescent gold nanoclusters (MU-Au NCs) was prepared by hydrothermal synthesis method using ammonium benzoate murexide (MU) as reducing agent and protecting agent.The synthesis method was simple and rapid.Based on the fluorescence quenching ability of spermine, a turn off type fluorescence analysis method was established for rapid and ultra sensitive detection of spermine.The linear range for detection of spermine was 0.003-300 μmol/L and the detection limit was 1 nmol/L (S/N=3).The established analytical method of spermine provided theoretical basis and reference for construction of spermine biosensor and actual sample detection.

Validation of an HPLC-UV method for the identification and quantification of bioactive amines in chicken meat / Validação de metodologia por HPLC/UV para identificação e quantificação de aminas bioativas em carne de frango de corte

A high-performance liquid chromatography with ultraviolet detection (HPLC-UV) method was validated for the study of bioactive amines in chicken meat. A gradient elution system with an ultraviolet detector was used after extraction with trichloroacetic acid and pre-column derivatization with dansyl chloride. Putrescine, cadaverine, histamine, tyramine, spermidine, and spermine standards were used for the evaluation of the following performance parameters: selectivity, linearity, precision, recovery, limits of detection, limits of quantification and ruggedness. The results indicated excellent selectivity, separation of all amines, a coefficient of determination greater than 0.99 and recovery from 92.25 to 102.25% at the concentration of 47.2mg.kg-1, with a limit of detection at 0.3mg.kg-1 and a limit of quantification at 0.9mg.kg-1 for all amines, with the exception of histamine, which exhibited the limit of quantification, of 1mg.kg-1. In conclusion, the performance parameters demonstrated adequacy of the method for the detection and quantification of bioactive amines in chicken meat.(AU)

Um método de cromatografia líquida de alta eficiência (CLAE) para pesquisa de aminas bioativas em carne de frango foi validado. Foi utilizado um sistema de gradiente de eluição com detector ultravioleta, após extração com ácido tricloroacético e derivação pré-coluna com cloreto de dansila. Os padrões de putrescina, cadaverina, histamina, tiramina, espermidina e espermina foram utilizados para avaliação dos seguintes parâmetros de desempenho: seletividade, linearidade, precisão, recuperação, limites de detecção, limites de quantificação e robustez. Os resultados mostraram excelente seletividade e separação de todas as aminas, coeficiente de determinação superior a 0,99, recuperação entre 92,25 e 105,25% na concentração 47,2mg.kg-1, limites de detecção de 0,3mg.kg-1 e limite de quantificação de 0,9mg.kg-1 para todas as aminas, com exceção da histamina, que apresentou o limite de quantificação mais alto, de 1mg.kg-1. Foi concluído que os parâmetros de desempenho demonstraram adequação do método para detecção e quantificação de aminas bioativas em carne de frango.(AU)

Bacteria isolated from Korean black raspberry vinegar with low biogenic amine production in wine

Abstract A high concentration of histamine, one of the biogenic amines (BAs) usually found in fermented foods, can cause undesirable physiological side effects in sensitive humans. The objective of this study is to isolate indigenous Acetobacter strains from naturally fermented Bokbunja vinegar in Korea with reduced histamine production during starter fermentation. Further, we examined its physiological and biochemical properties, including BA synthesis. The obtained strain MBA-77, identified as Acetobacter aceti by 16S rDNA homology and biochemical analysis and named A. aceti MBA-77. A. aceti MBA-77 showed optimal acidity % production at pH 5; the optimal temperature was 25 °C. When we prepared and examined the BAs synthesis spectrum during the fermentation process, Bokbunja wine fermented with Saccharomyces cerevisiae showed that the histamine concentration increased from 2.72 of Bokbunja extract to 5.29 mg/L and cadaverine and dopamine was decreased to 2.6 and 10.12 mg/L, respectively. Bokbunja vinegar prepared by A. aceti MBA-77 as the starter, the histamine concentration of the vinegar preparation step was decreased up to 3.66 mg/L from 5.29 mg/L in the wine preparation step. To our knowledge, this is the first report to demonstrate acetic acid bacteria isolated from Bokbunja seed vinegar with low spectrum BA and would be useful for wellbeing vinegar preparation.

Uso de aminas bioativas na dieta de aves de corte: uma revisão / Use of bioactive amines in the cutting bird diet: a review

Aminas bioativas vêm, ao longo dos anos, despertando o interesse dos pesquisadores no que se refere aos benefícios e aos prejuízos da sua presença ou mesmo do seu uso intencional, principalmente na alimentação de aves de corte, refletindo posteriormente na qualidade da carne produzida pelas mesmas. A presença de determinadas aminas em rações de aves de corte pode beneficiar e acelerar o desenvolvimento das mesmas, no entanto, quando presente em níveis elevados pode retardar o crescimento, causar disfunções metabólicas ou mesmo a morte dos animais. Estudos vêm sendo realizados a fim de definir quantidades ideais e tipos de aminas a ser adicionada à dieta a fim de propiciar um desenvolvimento adequado às aves sem, no entanto, apresentar resíduos na carne das mesmas.

Avaliação da qualidade interna de ovos de consumo pela pesquisa do teor de aminas bioativas / Evaluation of the internal quality of commercial eggs by searching of the bioactive levels

Com o objetivo de avaliar a qualidade dos ovos de consumo pela pesquisa dos níveis de aminas bioativas, foram coletados, pelos serviços de inspeção oficiais, 224 amostras de ovos provenientes de cinco regiões distintas do estado de Minas Gerais, durante o período de um ano. As aminas biogênicas (putrescina, cadaverina, feniletilamina, histamina e tiramina) e as poliaminas (espermidina e espermina) foram pesquisadas por cromatografia líquida de alta eficiência e detecção ultravioleta (CLAE/UV) após derivação pré-coluna com cloreto de dansila. Os resultados demonstraram que a putrescina estava presente, em baixas concentrações, em todas as amostras de gema e de albúmen. As demais aminas também foram detectadas, porém em menor frequência, e a espermina somente foi encontrada em uma amostra de albúmen. Foi concluído que os ovos de consumo produzidos no estado de Minas Gerais não são uma fonte considerável de poliaminas, importantes para o crescimento e a proliferação celular, e os baixos teores de aminas biogênicas, formadas pela descarboxilação de aminoácidos por enzimas bacterianas, não representam riscos à saúde do consumidor, o que indica que o ovo apresenta boa qualidade, tomando por base o critério de aminas bioativas.

In order to evaluate the quality of commercial eggs by searching the bioactive amine levels, 224 samples of eggs from the five regions of Minas Gerais State were collected during one year by the official inspection service. The biogenic amines (putrescine, cadaverine, phenylethylamine, histamine and tyramine) and the polyamines (spermidine and spermine) were determined by high performance liquid chromatography with ultraviolet detection (HPLC/UV) and pre-column derivatization with dansyl chloride. The results demonstrated the presence of putrescine in all samples of yolk and albumen, but in low concentrations. The other amines were also detected, however, with a lower frequency, and spermine was found only in one sample of albumen. It was concluded that the commercial eggs produced in Minas Gerais State are not a considerable source of polyamines, important for growth and cell proliferation; and low levels of biogenic amine, formed by decarboxylation of amino acids by bacterial enzymes, do not represent risks to consumer health, indicating that it has good quality, based on the bioactive amine criterion.