Improving postharvest life, quality and bioactive compounds of strawberry fruits using spermine and spermidine.

Small fruits such as strawberries, are a good source of natural antioxidants. In recent decades, many efforts have been made to increase the shelf life of strawberries and maintain its nutritional value in post-harvest conditions. In the present study, the effects of spermine (Spm) and spermidine (Spd) (0, 1.0 and 1.5 mM) on the post-harvest life and quality of strawberry fruits during the 3rd, 6th, and 12th days of storage, were investigated. Applications of Spm and Spd decreased the rate of weight loss, fruit decay, soluble solids content, fruit juice pH and taste index during the storage period in compared to the control. However, titratable acids and vitamin C contents, tissue stiffness, phenolic compounds and antioxidant activity increased in compared to the control. These growth regulators prevented the aging and loss of bioactive compounds of the fruit by increasing the antioxidant activity and preventing the destruction of the fruit tissue. Among the studied treatments, applications of 1.5 mM of Spm and Spd were the most effective treatments to enhance the storage life and quality characters of strawberry fruits.

Structural basis of amine odorant perception by a mammal olfactory receptor.

Odorants are detected as smell in the nasal epithelium of mammals by two G-protein-coupled receptor families, the odorant receptors and the trace amine-associated receptors1,2 (TAARs). TAARs emerged following the divergence of jawed and jawless fish, and comprise a large monophyletic family of receptors that recognize volatile amine odorants to elicit both intraspecific and interspecific innate behaviours such as attraction and aversion3-5. Here we report cryo-electron microscopy structures of mouse TAAR9 (mTAAR9) and mTAAR9-Gs or mTAAR9-Golf trimers in complex with ß-phenylethylamine, N,N-dimethylcyclohexylamine or spermidine. The mTAAR9 structures contain a deep and tight ligand-binding pocket decorated with a conserved D3.32W6.48Y7.43 motif, which is essential for amine odorant recognition. In the mTAAR9 structure, a unique disulfide bond connecting the N terminus to ECL2 is required for agonist-induced receptor activation. We identify key structural motifs of TAAR family members for detecting monoamines and polyamines and the shared sequence of different TAAR members that are responsible for recognition of the same odour chemical. We elucidate the molecular basis of mTAAR9 coupling to Gs and Golf by structural characterization and mutational analysis. Collectively, our results provide a structural basis for odorant detection, receptor activation and Golf coupling of an amine olfactory receptor.

Identification and characterization of phenolamides in tea (Camellia sinensis) flowers using ultra-high-performance liquid chromatography/Q-Exactive orbitrap mass spectrometry.

Phenolamides (PAs) are important secondary metabolites present in plants with multiple bioactivities. This study aims to comprehensively identify and characterize PAs in tea (Camellia sinensis) flowers using ultra-high-performance liquid chromatography/Q-Exactive orbitrap mass spectrometry based on a lab-developed in-silico accurate-mass database. The PAs found in tea flowers were conjugates of Z/E-hydroxycinnamic acids (p-coumaric, caffeic and ferulic acids) with polyamines (putrescine, spermidine and agmatine). The positional and Z/E isomers were distinguished through characteristic MS2 fragmentation rules and chromatographic retention behavior summarized from some synthetic PAs. 21 types of PAs consisting of over 80 isomers were identified, and the majority of them were found in tea flowers for the first time. Among 12 tea flower varieties studied, they all possessed tris-(p-coumaroyl)-spermidine with the highest relative content, and C. sinensis 'Huangjinya' had the highest total relative contents of PAs. This study shows the richness and structural diversity of PAs in tea flowers.

High-Dose Spermidine Supplementation Does Not Increase Spermidine Levels in Blood Plasma and Saliva of Healthy Adults: A Randomized Placebo-Controlled Pharmacokinetic and Metabolomic Study.

(1) Background: Spermidine is a biogenic polyamine that plays a crucial role in mammalian metabolism. As spermidine levels decline with age, spermidine supplementation is suggested to prevent or delay age-related diseases. However, valid pharmacokinetic data regarding spermidine remains lacking. Therefore, for the first time, the present study investigated the pharmacokinetics of oral spermidine supplementation. (2) Methods: This study was designed as a randomized, placebo-controlled, triple-blinded, two-armed crossover trial with two 5-day intervention phases separated by a washout phase of 9 days. In 12 healthy volunteers, 15 mg/d of spermidine was administered orally, and blood and saliva samples were taken. Spermidine, spermine, and putrescine were quantified by liquid chromatography-mass spectrometry (LC-MS/MS). The plasma metabolome was investigated using nuclear magnetic resonance (NMR) metabolomics. (3) Results: Compared with a placebo, spermidine supplementation significantly increased spermine levels in the plasma, but it did not affect spermidine or putrescine levels. No effect on salivary polyamine concentrations was observed. (4) Conclusions: This study's results suggest that dietary spermidine is presystemically converted into spermine, which then enters systemic circulation. Presumably, the in vitro and clinical effects of spermidine are at least in part attributable to its metabolite, spermine. It is rather unlikely that spermidine supplements with doses <15 mg/d exert any short-term effects.

Pentafluoropropionic Anhydride Derivatization and GC-MS Analysis of Histamine, Agmatine, Putrescine, and Spermidine: Effects of Solvents and Starting Column Temperature.

Gas chromatography-mass spectrometry (GC-MS) is useful for the quantitative determination of the polyamines spermidine (SPD) and putrescine (PUT) and of the biogenic amine agmatine (AGM) in biological samples after derivatization. This GC-MS method involves a two-step extraction with n-butanol and hydrochloric acid, derivatization with pentafluoropropionic anhydride (PFPA) in ethyl acetate, and extraction of the pentafluoropropionic (PFP) derivatives by toluene of SPD, PUT, and AGM. We wanted to extend this GC-MS method for the biogenic amine histamine (HA), but we faced serious problems that did not allow reliable quantitative analysis of HA. In the present work, we addressed this issue and investigated the derivatization of HA and the effects of toluene and ethyl acetate, two commonly used water-insoluble organic solvents in GC-MS, and oven temperature program. Derivatization of unlabelled HA (d0-HA) and deuterium-labelled HA (d4-HA) with PFPA in ethyl acetate (PFPA-EA, 1:4, v/v; 30 min, 65 °C) resulted in the formation of d0-HA-(PFP)2 and d4-HA-(PFP)2 derivatives. d4-HA and 13C4-SPD were used as internal standards for the amines after standardization. Considerable quantitative effects of toluene and ethyl acetate were observed. The starting GC column temperature was also found to influence considerably the GC-MS analysis of HA. Our study shows the simultaneous quantitative analysis of HA as HA-(PFP)2, AGM as AGM-(PFP)3, PUT as PUT-(PFP)2, and SPD as SPD-(PFP)3 derivatives requires the use of ethyl acetate for their extraction and injection into the GC-MS apparatus and a starting GC column temperature of 40 °C instead of 70 °C. The PFP derivatives of HA, AGM, PUT, and SPD were found to be stable in ethyl acetate for several hours at room temperature. Analytically satisfactory linearity, precision, and accuracy were observed for HA, AGM, PUT, and SPD in biologically relevant ranges (0 to 700 pmol). The limits of detection of AGM, PUT, and SPD were about two times lower in ethyl acetate compared to toluene (range, 1-22 fmol). The limits of detection were 1670 fmol for d0-HA and 557 fmol for d4-HA. Despite the improvements achieved in the study for HA, its analysis by GC-MS as a PFP derivative is challenging and less efficient than that of PUT, AGM, and SPD.

A new macrocyclic spermidine alkaloid from the aerial part of Hyssopus cuspidatus Boriss.

Hyssopus cuspidatus Boriss. grows in Xinjiang, China. A new macrocyclic spermidine alkaloid, namely hyssopusizine (1), along with sixteen known compounds were isolated and identified from the aerial parts of H. cuspidatus. Their structures were elucidated on the basis of spectroscopic data and comparison with the literature. Among them, fifteen compounds were isolated from H. cuspidatus for the first time. The absolute configuration of compound 1 was established by comparing the calculated and experimental ECD spectroscopic data. All isolated compounds were tested for their antioxidant and antimicrobial activities. Among them, compound 10 exhibited significant effects on ABTS free-radical scavenging activity with an IC50 value of 15.6 µM. Compounds 5-7 exhibited potent antioxidant activities against ABTS and DPPH. Most compounds exhibited moderate antimicrobial activities. Hyssopusizine (1) is the first macrocyclic spermidine alkaloid discovered from the Hyssopus genus.

Genetic mapping of sexually dimorphic volatile and non-volatile floral secondary chemistry of a dioecious willow.

Secondary chemistry often differs between sexes in dioecious plant species, a pattern attributed to its possible role in the evolution and/or maintenance of dioecy. We used GC-MS to measure floral volatiles emitted from, and LC-MS to quantitate non-volatile secondary compounds contained in, female and male Salix purpurea willow catkins from an F2 family. Using the abundance of these chemicals, we then performed quantitative trait locus (QTL) mapping to locate them on the genome, identified biosynthetic candidate genes in the QTL intervals, and examined expression patterns of candidate genes using RNA-seq. Male flowers emitted more total terpenoids than females, but females produced more benzenoids. Male tissue contained greater amounts of phenolic glycosides, but females had more chalcones and flavonoids. A flavonoid pigment and a spermidine derivative were found only in males. Male catkins were almost twice the mass of females. Forty-two QTL were mapped for 25 chemical traits and catkin mass across 16 of the 19 S. purpurea chromosomes. Several candidate genes were identified, including a chalcone isomerase associated with seven compounds. A better understanding of the genetic basis of the sexually dimorphic chemistry of a dioecious species may shed light on how chemically mediated ecological interactions may have helped in the evolution and maintenance of dioecy.

Influence of Brewing Process on the Profile of Biogenic Amines in Craft Beers.

The evaluation of the biogenic amines (BAs) profile of different types of craft beers is herein presented. A previously developed and validated analytical method based on ion-pair chromatography coupled with potentiometric detection was used to determine the presence of 10 BAs. Good analytical features were obtained for all amines regarding linearity (R2 values from 0.9873 ± 0.0015 to 0.9973 ± 0.0015), intra- and inter-day precision (RSD lower than 6.9% and 9.7% for beer samples, respectively), and accuracy (recovery between 83.2-108.9%). Detection and quantification limits range from 9.3 to 60.5 and from 31.1 to 202.3 µg L-1, respectively. The validated method was applied to the analysis of four ale beers and one lager craft beer. Ethylamine, spermidine, spermine, and tyramine were detected in all analyzed samples while methylamine and phenylethylamine were not detected. Overall, pale ale beers had a significantly higher total content of BAs than those found in wheat pale and dark samples. A general least square regression model showed a good correlation between the total content of BAs and the brewing process, especially for Plato degree, mashing, and fermentation temperatures. Knowledge about the type of ingredients and manufacturing processes that contribute to higher concentrations of these compounds is crucial to ensuring consumer safety.

Hydroxycinnamic acid-spermidine amides from Tetragonisca angustula honey as anti-Neospora caninum: In vitro and in silico studies.

Tetragonisca angustula honey was fractioned in a SiO2 column to furnish three fractions (A-C) in which four hydroxycinnamic acid-Spermidine amides (HCAAs), known as N', N″, N‴-tris-p-coumaroyl spermidine, N', N″-dicaffeoyl, N‴-coumaroyl spermidine, N', N″, N‴-tris-caffeoyl spermidine and N', N″-dicaffeoyl and N‴-feruloyl spermidine were identified in the fractions B and C by electrospray ionization tandem mass spectrometry. A primary culture model previously infected with Neospora caninum (72 h) was used to evaluate the honey fractions (A-C) for two-time intervals: 24 and 72 h. Parasitic reduction ranged from 38% on fraction C (12.5 µg/ml), after 24 h, to 54% and 41% with fractions B and C (25 µg/ml) after 72 h of treatment, respectively. Additionally, HCAAs did not show any cell toxicity for 24 and 72 h. For infected cultures (72 h), the active fractions B (12.5 µg/ml) and C (25 µg/ml) decreased their NO content. In silico studies suggest that HCAAs may affect the parasite's redox pathway and improve the oxidative effect of NO released from infected cells. Here, we presented for the first time, that HCAAs from T. angustula honey have the potential to inhibit the growth of N. caninum protozoa.

Influence of Breastfeeding Factors on Polyamine Content in Human Milk.

The polyamine content of human breast milk, which is the first exogenous source of polyamines for the newborn, can be affected by several factors associated with the mother, the infant, or breastfeeding itself. The aim of this study was to evaluate the influence of different breastfeeding factors on the polyamines found in human milk. For this study, a cohort of 83 mothers was considered for up to 4 months, and a subgroup of 33 mothers were followed during the first six months of breastfeeding. Two breast milk samples were collected at each sampling point (foremilk and hindmilk) and the polyamine content was determined by UHPLC-FL. Polyamine levels varied considerably between the mothers and tended to decrease over time. Putrescine was the minor polyamine, whereas spermidine and spermine contents were very similar. The concentrations of the three polyamines were significantly higher in hindmilk than foremilk (p < 0.001). Spermidine and spermine levels decreased significantly through the lactation progress (p < 0.05). Finally, slightly higher levels of polyamines were observed in the milk of mothers providing partial, rather than full, breastfeeding, although the differences were not significant. The polyamine content in human milk was found to change during a single feed (foremilk versus hindmilk) and as lactation progressed, mainly in response to the specific circumstances of the newborn.

Determination of 8 biogenic amines in aquatic products and their derived products by high-performance liquid chromatography-tandem mass spectrometry without derivatization.

A method for the determination of 8 biogenic amines in aquatic products and their derived products was established by HPLC-MS/MS without derivatization. The samples were extracted by 5% perchloric acid solution. N-hexane was used to clean the extract. The analytes were separated by a column of ACQUITY UPLC HSS T3 (100 mm × 2.1 mm, 1.8 µm), and gradient eluted with a mixed solution of (0.5% formic acid) and acetonitrile. Good linearity was obtained with correlation coefficients (R2) >0.99. This method achieved higher sensitivity (from 0.1 mg/kg for tyramine, 2-phenylethylamine and tryptamine to 1.0 mg/kg for spermidine, spermine, cadaverin, histamine and putrescine). The average recoveries were demonstrated in the range of 70.9%-113.1%, with relative standard deviations (RSDs) from 0.33% to 10.81%. This method was suitable for the detection of BAs in aquatic products and their products.

Application of gold and silver nanoparticles for selective assay of spermine in mixture with spermidine.

AIM: To assess the applicability of the novel technique based on the detection of spermine in solutions by spectrocolorimetric method using gold and silver colloidal nanoparticles. MATERIALS AND METHODS: Colloidal solution of gold nanoparticles were synthesized by chemical reduction of tetrachlorauric acid with trisodium citrate. Colloidal solution of silver nanoparticles was obtained by chemical reduction of silver nitrate with tryptophan. The absorption spectra of gold/silver metal colloids and their mixtures with polyamines were recorded. RESULTS: The increase of spermine concentration in solution caused the change in the intensity of the band of localized surface plasmon resonance that was not affected by the excess of spermidine. The color shift in colloidal gold due to its aggregation with spermine was registered spectrophotometrically. CONCLUSION: The principal possibility of selective quantification of spermine in the presence of spermidine in extremely high concentration using colloidal gold has been shown. This method can be used to assay selectively spermine in biological fluids.

Enriched metabolites that potentially promote age-associated diseases in subjects with an elderly-type gut microbiota.

We previously investigated the gut microbiota of 453 healthy Japanese subjects aged 0 to 104 years and found that the composition of the gut microbiota could be classified into some age-related clusters. In this study, we compared fecal metabolites between age-matched and age-mismatched elderly subjects to examine the roles of the gut microbiota in the health of the elderly. Fecal metabolites in 16 elderly subjects who fell into an age-matched cluster (elderly-type gut microbiota group, E-GM) and another 16 elderly subjects who fell into an age-mismatched cluster (adult-type gut microbiota group, A-GM) were measured by CE-TOF-MS. A total of eight metabolites were significantly different between the groups: cholic acid and taurocholic acid were enriched in the A-GM group, whereas choline, trimethylamine (TMA), N8-acetylspermidine, propionic acid, 2-hydroxy-4-methylvaleric acid, and 5-methylcytosine were enriched in the E-GM group. Some metabolites (choline, TMA, N8-acetylspermidine) elevated in the E-GM group were metabolites or precursors reported as risk factors for age-associated diseases such as arteriosclerosis and colorectal cancer. The abundance of some species belongs to Proteobacteria, which were known as TMA-producing bacteria, was increased in the E-GM group and correlated with fecal TMA levels. In vitro assays showed that these elderly-type fecal metabolites suppressed the expression of genes related to tight junctions in normal colonic epithelial cells and induced the expression of inflammatory cytokines in colon cancer cells. These findings suggest that metabolites produced by the aged gut microbiota could contribute to intestinal and systemic homeostasis and could be targeted for preventing aging-associated diseases.

Sphingomonas palmae sp. nov. and Sphingomonas gellani sp. nov., endophytically associated phyllosphere bacteria isolated from economically important crop plants.

In this study, two endophytic bacterial strains designated JS21-1T and S6-262T isolated from leaves of Elaeis guineensis and stem tissues of Jatropha curcas respectively, were subjected for polyphasic taxonomic approach. On R2A medium, colonies of strains JS21-1T and S6-262T are orange and yellow, respectively. Phylogenetic analyses using 16S rRNA gene sequencing and whole-genome sequences placed the strains in distinct clades but within the genus Sphingomonas. The DNA G + C content of JS21-1T and S6-262T were 67.31 and 66.95%, respectively. Furthermore, the average nucleotide identity and digital DNA-DNA hybridization values of strains JS21-1T and S6-262T with phylogenetically related Sphingomonas species were lower than 95% and 70% respectively. The chemotaxonomic studies indicated that the major cellular fatty acids of the strain JS21-1T were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c), C16:0, and C14:0 2OH; strain S6-262T possessed summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH) and summed feature 8 (C18:1 ω6c and/or C18:1 ω7c). The major quinone was Q10, and the unique polyamine observed was homospermidine. The polar lipid profile comprised of mixture of sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and certain uncharacterised phospholipids and lipids. Based on this polyphasic evidence, strains JS21-1T and S6-262T represent two novel species of the genus Sphingomonas, for which the names Sphingomonas palmae sp. nov. and Sphingomonas gellani sp. nov. are proposed, respectively. The type strain of Sphingomonas palmae sp. nov. is JS21-1T (= DSM 27348T = KACC 17591T) and the type strain of Sphingomonas gellani sp. nov. is S6-262T (= DSM 27346T =  KACC 17594T).

Simultaneous determination of eight arginine-related metabolites in cellular extracts using liquid chromatography-tandem mass spectrometry.

A simple, sensitive, and rapid liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method was developed for the simultaneous determination of arginine and its pathway-related metabolites (ornithine, proline, citrulline, glutamate, agmatine, spermidine, and spermine) in cellular extracts. Cells were lysed and cellular proteins precipitated by the addition of acetonitrile followed by ultra-sonication. Supernatants were analyzed using a Chromolith High Resolution RP-18 endcapped column (100 × 4.6 mm, 1.15 µm, 150 Å), with mobile phases of 0.1% formic acid solution and 0.1% formic acid in acetonitrile. Detection was carried out in multiple reaction monitoring (MRM) mode. Calibration curves showed linearity (r2 > 0.99) for all metabolites over the calibration ranges used. The intra- and inter-day precision was less than 13.5%, and the accuracy was between 91.3 and 114.7%. The method developed in this study was successfully applied to measure arginine and its pathway-related metabolites, which are related to nitric oxide synthase/arginase pathways in mouse bone marrow-derived dendritic cells (BMDCs). The ability to simultaneously measure arginine and its pathway-related metabolites is valuable for better understanding local and systemic inflammatory processes.

Intervening in sibling competition for assimilates by controlled pollination prevents seed abortion under postpollination drought in maize.

During maize production, drought throughout the flowering stage usually induces seed abortion and yield losses. The influence of postpollination drought stress on seed abortion and its underlying mechanisms are not well characterized. By intervening in the competition for assimilates between kernel siblings under different degrees of postpollination drought stresses accompanied by synchronous pollination (SP) and incomplete pollination (ICP) approaches, the mechanisms of postpollination abortion were investigated at physiological and molecular levels. Upon SP treatment, up to 15% of the fertilized apical kernels were aborted in the drought-exacerbated competition for assimilates. The aborted kernels exhibited weak sucrose hydrolysis and starch synthesis but promoted the synthesis of trehalose-6-phosphate and ethylene. In ICP where basal pollination was prevented, apical kernel growth was restored with reinstated sucrose metabolism and starch synthesis and promoted sucrose and hexose levels under drought stress. In addition, the equilibrium between ethylene and polyamine in response to the drought and pollination treatments was associated with the abortion process. We conclude that competition for assimilates drives postpollination kernel abortion, whereas differences in sugar metabolism and the equilibrium between ethylene and polyamines may be relevant to the "live or die" choice of kernel siblings during this competition.

Regulation of the biosynthesis of endogenous nitric oxide and abscisic acid in stored peaches by exogenous nitric oxide and abscisic acid.

BACKGROUND: Nitric oxide (NO) and abscisic acid (ABA) are important regulators of plant response to cold stress, and they interact in response to cold signals. The primary goal of this study was to determine the roles of exogenous NO and ABA on the synthesis of endogenous NO and ABA in cold-stored peach fruit. RESULTS: Exogenous NO and ABA maintained a relatively high content of NO, increased nitrate reductase (NR) activity, and inhibited the activity of NO synthase (NOS)-like and the levels of polyamine biosynthesis in peaches during cold storage. Treatments of potassium 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), NO, N-nitro-l-Arg-methyl ester (L -NAME), and sodium tungstate did not influence ABA content. Exogenous ABA increased the content of carotenoids and the activities of aldehyde oxidase (AO), 9-cis-epoxycarotenoid dioxygenase (NCED), and zeaxanthin epoxidase (ZEP) of ABA synthesis in peaches during cold storage, and upregulated the gene expression of PpAO1, PpNCED1, PpNCED2, and PpZEP. The production of endogenous NO was differentially inhibited by NO scavengers, ABA inhibitors, and NR inhibitors, but not affected by NOS-like inhibitors during cold storage. CONCLUSION: Exogenous NO and ABA can induce endogenous NO synthesis in cold-stored peaches by the nitrate reductase pathway, and ABA can mediate endogenous ABA synthesis by the autocatalytic reaction. NO does not regulate ABA synthesis. © 2019 Society of Chemical Industry.

Chemical profiling of spermidines in goji berry by strong cation exchange solid-phase extraction (SCX-SPE) combined with ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS/MS).

Lycium barbarum fruit (Goji berry) have been used as a traditional Chinese medicine (TCM) with its outstanding biological and pharmacological activities. Spermidine alkaloids are a major class of bioactive constituents in goji berry, nevertheless, detailed information related to its identification remains scarce. In this study, chemical profiling of spermidines in goji berry was carried out by ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Four structure types of standards were used to study the comprehensive fragmentation rules of spermidines. Different types of spermidines were identified by distinctive MS/MS fragment ions. Noticeably, it was first proposed that the co-existence of fragment ions at m/z 220 and 222 was the key characteristic for distinguishing spermidine isomers. According to the structural feature of spermidines, a quick, convenient, highly selective strong cation exchange solid-phase extraction (SCX-SPE) combined with RP-LC procedure was developed for selective enrichment and the MS detection compatibility. A total of 41 out of 58 spermidines were tentatively characterized using the established method, of which 26 were reported for the first time from goji berry. This study provides guidelines and references for the identification of spermidines in natural products.

Detection of polyamines using immunobiosensor based on zinc oxide nanoparticles.

AIM: To analyze the performance of biosensor based on nanoparticles of zinc oxide for the detection of spermine and spermidine in solution and in cell culture. MATERIALS AND METHODS: Zinc oxide nanoparticles were used for preparing biosensor containing antibodies to spermine and spermidine. Polyamine concentration is solutions of spermine and spermidine as well as in lyophilisate of MCF-7 cells was measured by luminescence of the samples excited by laser beam at 380 nm. RESULTS: The minimum concentration for the detection of polyamines in model solutions is 10 ng/ml, and maximum one is 100 ng/ml. A higher level of luminescence intensity of nanoparticles was found during analysis the polyamines in MCF-7 lyophilisate allowing for detecting polyamines at concentrations from 100 cells/ml to 100,000 cells/ml. CONCLUSIONS: The proposed biosensor system for determining the level of biogenic polyamines in cell lyophilisate using the optical properties of zinc oxide nanoparticles is promising for further improvement of the methodology and its implementation for detection and measurement of polyamines in biological systems.

Bioactive amines changes during the ripening and thermal processes of bananas and plantains.

Bioactive amines are found in food and can be relevant for the assessment of fruits shelf life and nutritional quality. The pulp and peel of 20 banana and plantain were analyzed and the bioactive amine content varied according to the genotype, ripening stage, fruit tissue and thermal processing. In most of the analyzed genotypes, tyramine, histamine, dopamine, serotonin, spermidine, and spermine were decreased during the ripening process in the pulps. By contrast, there was an increase in putrescine level. In many genotypes of plantains, the serotonin and dopamine contents in pulp decreased until stage 5 and increased at stage 7. Peels contain higher levels of serotonin, dopamine, histamine and tyramine than pulps. Additionally, thermal processing affects the content of amines present in fruit. Boiling with the peel should be preferred in domestic preparations, regardless of the genotype used.