Histamine Content Research Articles

Mast Cell Population and Histamine Content in Hypothyroid Rat Tissues.

Simple SummaryIn this study, we investigated the putative regulatory role of the pituitary–thyroid axis on mast cells (MCs). We found that hypothyroidism resulted in a significant increase in number of MCs and the histamine content in the skin and exorbital lacrimal gland of Wistar rats, Rattus norvegicus. Furthermore, an increase in the percentage of degranulating MCs suggests that the thyroid status also influences the activation state of these cells.The morphological features and relative number of mast cells (MCs) were studied in the skin and exorbital lacrimal glands of hypothyroid Wistar rats, Rattus norvegicus. Hypothyroidism significantly increased the number of MCs (up to 4.5-fold) and histamine content (up to 50%) in the examined tissues. The magnitude of the increase in the number of MCs was greater in the cheek skin and exorbital lacrimal glands than in the back skin. In the skin, the MCs were mainly located within the hypodermis and closely associated with the blood vessels, nerve fascicles, and adipocytes. In the exorbital lacrimal gland, which is a seromucous gland located lateral to the cheek below the ear, the MCs were distributed in the connective tissue surrounding the acini. The secretory granules of MCs showed histochemical characteristics of connective tissue MCs. They were metachromatic with Toluidine blue and safranin positive with the Alcian blue/safranin reactions. Finally, a significant increase in degranulating MCs was observed in hypothyroid tissues, relative to euthyroid tissues. At the ultrastructural level, the MCs of euthyroid rats were predominantly non-degranulating (Stage I). In hypothyroid animals, numerous MCs showed partial degranulation (Stage II–III) or were in a stage of complete degranulation. Our results concerning the skin and exorbital lacrimal gland suggested that the thyroid status might be involved in regulating the frequency and activation state of MCs.

Histamine Produced by Gram-Negative Bacteria Impairs Neutrophil’s Antimicrobial Response by Engaging the Histamine 2 Receptor

We found that histamine (10−9 M) did not have any effect on the in vitro capture of Escherichia coli by neutrophils but accelerated its intracellular killing. In contrast, histamine (10−6 M) delayed the capture of Escherichia coli by neutrophils and reduced the amounts of pHrodo zymosan particles inside acidic mature phagosomes. Histamine acted through the H4R and the H2R, which are coupled to the Src family tyrosine kinases or the cAMP/protein kinase A pathway, respectively. The protein kinase A inhibitor H-89 abrogated the delay in bacterial capture induced by histamine (10−6 M) and the Src family tyrosine kinase inhibitor PP2 blocked histamine (10−9 M) induced acceleration of bacterial intracellular killing and tyrosine phosphorylation of proteins. To investigate the role of histamine in pathogenicity, we designed an Acinetobacter baumannii strain deficient in histamine production (hdc::TOPO). Galleria mellonella larvae inoculated with the wild-type Acinetobacter baumannii ATCC 17978 strain (1.1 × 105 CFU) died rapidly (100% death within 40 h) but not when inoculated with the Acinetobacter baumannii hdc::TOPO mutant (10% mortality). The concentration of histamine rose in the larval haemolymph upon inoculation of the wild type but not the Acinetobacter baumannii hdc::TOPO mutant, such concentration of histamine blocks the ability of hemocytes from Galleria mellonella to capture Candida albicans in vitro. Thus, bacteria-producing histamine, by maintaining high levels of histamine, may impair neutrophil phagocytosis by hijacking the H2R.

IN VITRO ANTI-EMETIC EFFECT OF METHANOL ROOT EXTRACT OF TERMINALIA AVICENNIOIDES GUILL. & PERR. ON ISOLATED RABBIT ILEUM

Abstract Background: Terminalia avicennioides is a medicinal plant used traditionally in Nigeria to treat numerous ailments and disorders which include coughs, purgative and emetic. Objective: This study scientifically evaluated the probable mechanism of the anti-emetic activity of methanol root extract of Terminalia avicennioides Guill. & Perr. on histaminergic and serotonergic receptors of isolated rabbit ileum. Methodology: Fresh root bark was extracted using methanol and the antiemetic effect was evaluated by experimenting on a small segment (3 cm) of isolated rabbit ileum, using the data capsule (Ugo Basile) and single chamber isolated tissue apparatus. Varying concentrations of histamine and serotonin (0.05, 0.1, 0.2, and 0.4 mg/ml) were used to obtain contractions as they act on histamine and serotonergic receptors respectively. Results: META (0.05 mg/ml, 0.1 mg/ml, 0.2 mg/ml, and 0.4 mg/ml) exhibited a significant concentration-dependent decrease at p<0.05 in histamine-induced and serotonin-induced contractions on isolated rabbit ileum from the data capsule reading with percentage inhibition of 43.22, 53.96, 75.35, 85.58 % and 21.62, 49.50, 78.67 and 86.96 % respectively for the different concentrations. Conclusion: The study showed that methanol root extract of Terminalia avicennioides acts on cholinergic (muscarinic), histaminergic, and serotonergic receptors of isolated rabbit ileum by inhibitory spasmolytic action against smooth muscle contractility, hence its ability to possess anti-emetic effect to relieve vomiting.

Roles of Mast Cells in Cutaneous Diseases.

Mast cells are present in all vascularized tissues of the body. They are especially abundant in tissues that are in frequent contact with the surrounding environment and act as potential sources of inflammatory and/or regulatory mediators during development of various infections and diseases. Mature mast cells’ cytoplasm contains numerous granules that store a variety of chemical mediators, cytokines, proteoglycans, and proteases. Mast cells are activated via various cell surface receptors, including FcϵRI, toll-like receptors (TLR), Mas-related G-protein-coupled receptor X2 (MRGPRX2), and cytokine receptors. IgE-mediated mast cell activation results in release of histamine and other contents of their granules into the extracellular environment, contributing to host defense against pathogens. TLRs, play a crucial role in host defense against various types of pathogens by recognizing pathogen-associated molecular patterns. On the other hand, excessive/inappropriate mast cell activation can cause various disorders. Here, we review the published literature regarding the known and potential inflammatory and regulatory roles of mast cells in cutaneous inflammation, including atopic dermatitis, psoriasis, and contact dermatitis GVHD, as well as in host defense against pathogens.

Occurrence of Histamine Toxicity and Metal and Mineral Contaminants in Invasive Lionfish (Pterois volitans) in Grenada, West Indies

Targeted fishing of invasive lionfish (Pterois volitans and P. miles) in the Caribbean creates an opportunity to monitor lionfish for food safety and to examine their utility as environmental sentinel species. The goals of this study were to assess P. volitans for histamine toxicity (scombroid poisoning) and to quantify mineral and heavy metal contaminants in lionfish in Grenada, West Indies. Histamine concentrations in lionfish muscle significantly increased after heat stress but remained below maximum allowable concentrations for consumption. Mineral and heavy metal concentrations were tested in muscle and liver from lionfish from two separate reef systems using inductively coupled plasma–mass spectrometry. Total arsenic levels in liver were significantly higher in fish sampled from Boss's Reef than those from Halifax Harbor, but they were not interpreted as clinically significant. Lead, mercury, cadmium, copper, molybdenum, and cobalt were below the detectable limit of the analyzer. Thallium, selenium, iron, zinc, and manganese were detected in muscle and/or liver tissue at expected concentrations. Lionfish represent a low risk for histamine toxicity and have not bioaccumulated significant heavy metals in Grenada to pose a food safety risk. The higher arsenic concentrations in Boss's Reef suggest that the location should be monitored and studied in the future. The potential for lionfish to act as bioindicators for heavy metals is uncertain and needs further validation.

Study on the antipruritic mechanism of Zanthoxylum bungeanum and Zanthoxylum schinifolium volatile oil on chronic eczema based on H1R and PAR-2 mediated GRPR pathway.

To observe the antipruritic effect and mechanism of the volatile oil of Zanthoxylum bungeanum and Zanthoxylum schinifolium on chronic eczema to provide data support for clinical application and new drug development of Zanthoxylum bungeanum and Zanthoxylum schinifolium. The model of chronic eczema was established by using 2-dinitrochlorobenzene (DNCB), and the composition and content of volatile oil in Zanthoxylum schinifolium and Zanthoxylum bungeanum was determined by gas chromatography-mass spectrometry (GC-MS). The antipruritic effect by (EASI) score of eczema area and severity index and scratching times was then evaluated. Then, the contents of histamine, gastrin-releasing peptide (GRP), interleukin-4 (IL-4), and immunoglobulin E (IgE) in serum of rats was determined by enzyme-linked immunosorbent assay (ELISA). The tissue morphology was observed by HE staining. The expressions of H1R, PAR-2, TRPV1, TRPA1, and GRPR was then detected by immunohistochemistry, Western blot, and QRT-PCR. The results revealed that there were differences in the composition of volatile oil between Zanthoxylum bungeanum and Zanthoxylum schinifolium. Compared to the model group, the medium-dose group of Zanthoxylum bungeanum and Zanthoxylum schinifolium group significantly increased the difference of EASI score and scratching times, significantly decreased the concentrations of IL-4, IgE, GRP, and histamine, and significantly decreased the expression levels of H1R, PAR-2, TRPV1, and GRPR. The degree of inhibition on the pathological manifestations of chronic eczema was evident. There was no significant difference in antipruritic effect between the two groups. The expression of TRPA1 was inconsistent at the protein and gene level, which needs to be further researched. The volatile oil of Zanthoxylum bungeanum and Zanthoxylum schinifolium can reduce the expression of H1R, PAR-2, TRPV1, and GRPR. The mechanism may be through the H1R and PAR-2-mediated GRPR pathway intervention to achieve the effect, both of which have the same antipruritic effect.

Analysis of changes in simulated rancidification process during the storage of Huangjiu.

Huangjiu, a traditional Chinese wine with low alcoholic strength, can easily develop rancidification upon microbial contamination in the long‐term storage process. In order to analyze the changes in key indexes in the rancidification process during the storage of Huangjiu, a laboratory simulation of microbial contamination changes was carried out. Changes in microbiological indexes, physicochemical indexes, and volatile flavor compounds in the rancidification process of Huangjiu can be divided into two stages. Test results demonstrated that within the early stage of the rancidification process, multiplication of contaminating microorganisms was in the adaptation phase with a slow OD600 growth value of Huangjiu, while physicochemical indexes such as the pH and amino acid nitrogen content changed relatively slowly. The contents of aldehyde compounds in the volatile flavor components of Huangjiu declined quickly to be lower than 1.0 mg/L, while the conductivity index increased by 6%. In the late stage, the OD600 value of Huangjiu increased rapidly and microorganism multiplication entered the logarithmic phase. Furthermore, changes in the physicochemical indexes are accelerated. Specifically, the histamine content increased by 457% and the content of aldehydes remains lower than 1.0 mg/L. The conductivity index continued to rise by 25% in this stage. This indicates that the two rancidification stages have different influences on the quality of Huangjiu. The conductivity value can be used as a staged representative index throughout the rancidification of Huangjiu to distinguish between different batches and evaluate the degree of microbial contamination. Additionally, the conductivity index can be used for long‐term online monitoring of large tank storage of Huangjiu.

Inhibition of Microencapsulated Liquid Smoke on the Foodborne Pathogens and Histamine-Forming Bacterias’ Growth in Tuna Loin Sashimi

Sashimi, a unique and simple fresh fish dish, is commonly served at a restaurant or as a family dinner in Japan. Because sashimi was created from fresh tuna loin, it is easily ruined by spoilage germs and pathogens, particularly when served without ice. Apart from ice, new preservatives must be investigated to avoid pathogenic and histamine-producing microorganisms. Liquid smoke (LS) contains antimicrobial chemicals including organic acids, carbonyl, and phenols from pyrolyzing coconut shells. However, because the evidence of physicochemical features of LS is scarce, research into liquid smoke microencapsulation is required. 
 The researchers wanted to figure out how liquid smoke microencapsulation (LSM) is made, how effective it is against harmful germs, and how much total histamine is present in LSM-coated sashimi maintained at room temperature. Histamine content, antibacterial inhibitory activity, total microbial count (TPC) of Salmonella and E. coli, water content, and pH level were tested. According to the findings, LSM with maltodextrin: sago flour: 1% LS ratio of 10: 1: 5 efficiently prevented E. coli and Salmonella development and reduced histamine level in sashimi refrigerated for 6 days in the refrigerator.

Mixed metal oxide Bi2O3/Bi2WO6 thin films for the photoelectrocatalytic degradation of histamine

Photoelectrocatalytic technologies emerge as competitive strategy to manage increasing histamine concentrations. This work explores the synergistic benefits induced in the formation of mixed oxide semiconductor in solid solution. Photoelectrocatalytic films of Bi2O3, WO3, and their hybrid metal mixed oxide composition Bi2O3/Bi2WO6 were synthesized and characterized. Results demonstrate that Bi2O3/Bi2WO6 structure increases stability of charge carriers and enhances degradation performance. Applied bias potential was identified as driving variable that induces effective charge carrier stabilization for accelerated degradation of histamine in aqueous solution. Scavenger experiments identified •OH and O2•- as the main oxidant species produced during photoelectrocatalytic treatment.

Dynamics of Bacterial Composition and Association with Quality Formation and Biogenic Amines Accumulation during Fish Sauce Spontaneous Fermentation.

High-throughput sequencing and high-pressure liquid chromatography (HPLC) methods were used to investigate the influences of microbial dynamics on the quality and biogenic amine (BA) content during fish sauce fermentation. The homogeneity of total viable bacteria and lactic acid bacteria in fish sauce becomes higher as fermentation progresses. Tetragenococcus was the key genus of fish sauce fermentation. Carnobacterium (38.43%) and Lentibacillus (41.01%) were the dominant genera in the samples fermented for 3 months and 18 months, respectively. These three bacterial genera were significantly related to the physicochemical characteristics and characteristic flavors of the sauces. Tetragenococcus was significantly positively correlated with nitrogen oxides, the main characteristic flavor components in fish sauce. The BA content in fish sauce fermentation increased from 106.88 to 376.03 mg/kg, and the content of histamine reached 115.30 mg/kg at the end of fermentation, indicating that fish sauce has health risks. About 66.67% of Lentibacillus isolates were able to produce a large amount of BA, suggesting that Lentibacillus was the key genus for BA accumulation in fish sauce fermentation. Research on reducing the content of BA in fish sauce by intervening with regard to the fermentation temperature showed that a safe fish sauce product could be obtained at the fermentation temperature of about 25°C. These results help us to understand the contribution of microbial community composition to fish sauce fermentation and provide a basis for improving the quality and safety of fermented fish sauce. IMPORTANCE Traditional fermentation of fish sauce is mainly carried out by complex microbial communities from raw anchovies and processing environments. However, it is still unclear how the environmental microbiota influences the quality and the safety of fish sauce products. Therefore, this study comprehensively explained the influence of microorganisms on the quality and safety of fish sauce during the fermentation process in terms of physicochemical characters, flavors, and BA. Additionally, the accumulation of BA in fish sauce fermentation was controlled by intervening in the fermentation temperature. This finding contributes to a deeper understanding of the role of environmental microbiota during fermentation and provides data support for improving the safety of fish sauce.

Bienzymatic Spiky Janus Nanomotors Powered by Histamine

AbstractAs an important inflammatory mediator, histamine can be produced by many immune cells (mast cells, neutrophils, dendritic cells, platelets, etc.) and modulates a variety of immune events. Developing enzymatic micro/nanomotors from the perspective of immunometabolism is required but still lacking. In this work, we functionalized the histamine‐metabolizing enzyme onto the Janus Au/mSiO2 nanoparticles. Powered by the tandem catalytic decomposition of histamine initiated by a surface‐modified diamine oxidase, this nanomotor system exhibits an enhanced diffusive motion with increasing histamine concentration. At a concentration of histamine (500 mM), the motor speed reaches 9.25±1.71 μm.s−1, which is 2.3 times that of Brownian motion, and the corresponding diffusion coefficient is enhanced by 137%. This novel enzymatic nanomotor system not only expands the physiologic enzyme library for biomedical micro/nanomotors but also provides new ideas for the immune therapy of diseases targeting histamine.

Occurrence of Histamine in Commercial Cat Foods under Different Storage Conditions.

In fish-based foods, one of the effects of inappropriate storage can be the formation of biogenic amines. Among these, histamine is considered one of the most toxic. The purpose of the present study is to assess the occurrence of histamine in fish-based pet foods, and to evaluate the changes in histamine content during storage at different temperatures. For the analysis, an LC-MS/MS method was used. Fifty-eight pet foods were purchased, and an aliquot of them was analyzed just after opening the packages. Histamine was detected in 12 samples and concentrations ranged from 1.5 to 30.1 mg/kg. The remaining of each positive sample was divided into seven subsamples. One of them was used as a control sample and kept at −20 °C, while the other six were exposed to different environmental conditions. Samples exposed to room temperature showed no significant changes in histamine levels, while samples exposed to high temperatures showed significant increases in histamine content. Finally, samples exposed to refrigerator temperature showed a slight decrease in histamine levels. Under the experimental conditions, the EU limit of 100 mg/kg established for fishery products was never exceeded. These results seem to indicate a low risk of histamine intoxication in cats fed fish-based pet food.

Effect of Steam Explosion on Structural Characteristics of β-Conglycinin and Morphology, Chemical Compositions of Soybean Meal.

In this study, steam explosion was applied as a means to degrade β-conglycinin. We investigated changes in morphology, the chemical composition of soybean meal, and the structural characteristics of β-conglycinin. The results showed that steam explosion at 0.7 MPa for 8 min could effectively decrease the β-conglycinin content of soybean meal while the histamine content was not increased. The structural characteristics of soybean meal proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), and X-ray diffraction (XRD). Steam explosion caused the degradation of high weight proteins and reduced the band density of α’, α, and β subunits in β-conglycinin. The micro-surface of soybean meal seemed to be in the cracked or puffed stage and the color became brown or dark after steam explosion. Steam explosion facilitated the dissolution of water-extractable arabinoxylans, which are 4.81 fold higher than that of native soybean meal. Phytic acid was exposed to the hydrothermal environment of the steam explosion process and consequently degraded by 12.95–24.69%. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of soybean meal extract was gradually increased from 20.70 to 33.71% with the rising of treated pressure from 0.3 to 0.7 MPa, which was 1.11–1.81 fold of native extract. The steam explosion may be a new modification technology that could decrease antigenicity, and steam-exploded soybean meal (0.7 MPa, 8 min) with lower β-conglycinin and phytic acid content that could be widely used in food products.

Circadian molecular clock disruption in chronic pulmonary diseases.

The circadian clock is the biochemical oscillator with a near 24-h period that is responsible for generating the circadian rhythms in peripheral organs including the lung. Mounting evidence suggests that circadian clock disruption during chronic lung diseases plays an essential role in augmented oxidative stress, inflammatory response, metabolic imbalances, hypoxia/hyperoxia, mucus secretion, dysregulated autophagy, and alters pulmonary function. Here, we review circadian clock disruption and discuss candidate clock genes that are altered at the transcriptional or translational level in chronic pulmonary diseases. This review aims to provide the current knowledge and understanding of the circadian molecular clock disruption in chronic pulmonary diseases which will further advance the development of novel clock-based therapeutics in the future.

Ratiometric fluorescent nanosystem based on upconversion nanoparticles for histamine determination in seafood

Histamine is the prime culprit of toxicity resulting from seafood consumption, whereas conventional detection methods are not convenient to meet the needs of rapid histamine analysis nowadays. Based on upconversion nanoparticles (UCNPs) and inner filter effects (IFE), a novel ratiometric fluorescence nanosystem was developed for the efficient detection of histamine. Through pre-treatment with solid-phase extraction (SPE) and colorific azo coupling reaction of histamine, the fluorescence of UCNPs at 548 nm was quenched, while fluorescence at 664 nm was unchanged. Thus, ratiometric fluorescence I548/I664 was inversely proportional to histamine concentration at a wide range of 10–200 mg/L. The detection limit was 7.34 mg/L, one order of magnitude lower than that of the traditional colorimetric method (25 mg/L). In addition, such a convenient and environment-friendly detection system was further employed to quantify the histamine in fish, shrimp, and shellfish samples, showing excellent application potential in seafood safety.

Effect of Clemastine Fumarate on Perioperative Hemodynamic Instability Mediated by Anaphylaxis During Cardiopulmonary Bypass Surgery

BackgroundPerioperative hemodynamic instability mediated by anaphylaxis is a life-threatening complication in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). This study aimed to evaluate the effect of clemastine fumarate in this specific patient population.Material/MethodsWe enrolled 100 participants who met the inclusion criteria and randomly allocated them to the treatment group and the placebo group. Participants in the treatment group and the placebo group were treated separately with an injection of clemastine fumarate and saline, respectively. Plasma histamine concentration and blood pressure were quantified at 5 timepoints during the perioperative period, and differences between the 2 groups were assessed by repeated-measures ANOVA. The postoperative complications and in-hospital mortality also were evaluated. All participants were followed up for 7 days after cardiac surgery.ResultsPlasma histamine concentrations increased in both groups but were statistically significantly lower in the treatment group during the perioperative period (P=0.007). Diastolic blood pressure (P=0.014) and mean arterial pressure (P=0.024) in the treatment group were significantly higher than in the placebo group during the perioperative period. The coefficients of variation for systolic (13.9±4.2% vs 17.2±4.4%, P<0.01) and diastolic (12.9±4.9% vs 15.3±5.2%, P=0.02) blood pressure were significantly lower in the treatment group compared with the placebo group.ConclusionsPretreatment with clemastine fumarate restrains the increase in histamine concentration and provides safer hemodynamics in patients undergoing cardiac surgery with CPB.

Development and Validation of an RP-HPLC-FLD Method for the Determination of Biogenic Amines after Pre-column Derivatization with a New Pyrazoline Based Reagent, 3- Naphthyl-1-(4-trifluoromethyl)-5-(4-carboxy phenyl)-2-pyrazoline

Application of 3-Naphthyl-1-(4-trifluoromethyl)-5-(4-carboxy phenyl)-2-pyrazoline (NFCP) as a novel fluorigenic label for the derivatization of biogenic amines (BAs) and separation by liquid chromatography (LC) was investigated. Optimum conditions for the pre-column derivatization and chromatographic separation were investigated. The resulting derivatives are fluorescent at λex/λem: 380/460 nm. For the sake of evaluating the efficacy of the proposed analysis of BAs of different nature, the formation of nine NFCP-BAs derivatives was tested individually. Simultaneous derivatization and separation of four BAs (histamine, tyramine, tryptamine, and phenylethylamine) were achieved under the isocratic elution mode. Furthermore, the derivatives were identified by the characteristic product ion obtained during LC-MS/MS analysis. The viability of the method was established by measuring levels of histamine in fresh and spoiled fish samples. Histamine concentrations were found to be 0.4 µgg-1 and 4.1 µgg-1 in fresh and spoiled tuna fish samples respectively. As a simple, reliable, and sensitive pre-column derivatization method, this work provides for future research to develop a novel HPLC method for the analysis of BAs from food samples such as fish and various other matrices by utilizing the new pyrazoline compound.

Time-dependent effect of desensitization with wasp venom on selected parameters of the immune system

The emergence of tolerance during Hymenoptera venom immunotherapy (VIT) is a complex process. The main goal of VIT is to induce a change from proinflammatory Th2 response to the Th1 response. However, the immune mechanism of acquiring rapid tolerance during VIT has not yet been fully understood. Therefore, we have analyzed (in 4-time points: 0, 2, 6, and 24 weeks after the initiation phase of VIT) the concentration of complement C3, C4, and C5 components, lymphocyte subpopulations (flow cytometry), as well as histamine and tryptase serum concentrations of 43 patients with wasp venom allergy (III and IV Müller grade) classified to ultra-rush treatment and 18 volunteers as the control group (CG). We observed that VIT affected the immune system by inducing changes in the complement system (decreased C3 and C4 compartment protein concentrations) and "normalized" the percentage of lymphocytes and neutrophils in the peripheral blood. Moreover, a significant increase in the percentage of nTreg in the blood of patients treated with VIT was observed. On the other hand, there were no changes in histamine or tryptase concentrations in the blood. Increased percentage of nTreg cells is a well-known mechanism by which VIT affects the immune system. Finally, VIT also modulated the concentrations of the complement components, which may be a previously unknown VIT mechanism of action.

Inhibitory Effects of High-Hydrostatic-Pressure Processing on Growth and Histamine Formation of Histamine-Forming Bacteria in Yellowfin Tuna Meat during Storage.

Simple SummaryHigh-hydrostatic-pressure treatment effectively inhibited the growth and histamine formation of histamine-forming bacteria species in tuna meat during storage at low temperatures. Our findings can be used to enhance food safety and decrease the risk of histamine poisoning associated with consumption of tuna meat products.In the research, we evaluated the effects of high-pressure processing (HPP) on the growth and histamine formation of histamine-forming bacteria (HFB) in yellowfin tuna meat during storage. Tuna meat samples inoculated with the individual HFB species Morganella morganii and Photobacterium phosphoreum were subjected to HPP treatment at 250, 350, 450, and 550 MPa for 5 min, and the changes in bacterial count, total volatile basic nitrogen (TVBN) content, pH, and histamine content during storage at 4 and 15 °C were analyzed. The results indicate that the bacterial counts of the HFB species decreased significantly with increasing pressure, and HFB became undetectable in the samples treated at 450 and 550 MPa. At a storage temperature of 15 °C, the bacterial counts of both HFB species in the control group and samples subjected to HPP treatment at 250 and 350 MPa increased significantly with storage time. The bacterial counts of M. morganii in the samples stored at 4 °C decreased, whereas those of P. phosphoreum increased gradually owing to its psychrophilic nature. HPP treatment (>250 MPa) inhibited the increases in pH and TVBN content of the samples stored at 15 °C and delayed histamine formation in the samples during storage; these effects were more significant as the pressure during HPP treatment was increased.

Single Cell Plant Model of Equisetum arvense for the Study Antihistamine Effects of Azulene and Sesquiterpene Lactones

Single cell of vegetative microspore from spore-bearing plant field Equisetum arvense L. has been presented as a single-cell experimental model for the screening of native compounds acting as antihistamine agents. The effects of azulene, sesquiterpene lactones austricine, gaillardine, grosshemine, inulicine, and desacetylinulicine as well as sesquiterpene alcohol ledol, on the content of histamine in germinating horsetail microspores has been investigated by the fluorescent method. It has been shown using microspectrofluorimetry that these compounds are able to regulate the germination of microspores to varying degrees, as assessed by the autofluorescence of chlorophyll, in a medium without and in the presence of 0.5–1% sodium sulfate as a salt stress factor. A fluorescent histochemical reaction to histamine with ortho-phthalic aldehyde in cells and secretory mucilage revealed the ability of the compounds studied to reduce the level of this biogenic amine depending on their structure in the following order: grosshemine &gt; azulene &gt; austricine &gt; ledol. Gaillardine, inulicine, and desacetylinulicine showed weak antihistamine activity