Decarboxylase Gene Expression Research Articles

Elucidating the potential of chlorogenic acid for controlling Morganella psychrotolerans growth and histamine formation.

To investigate the inhibitory impact of chlorogenic acid (CGA) on the growth of Morganella psychrotolerans and its ability to form histamine. The antimicrobial effect of CGA on M. psychrotolerans was evaluated using the minimum inhibitory concentration (MIC) method, revealing an MIC value of 10mg ml-1. The alkaline phosphatase (AKP) activity, cell membrane potential, and scanning electron microscopy images revealed that CGA treatment disrupted cell structure and cell membrane. Moreover, CGA treatment led to a dose-dependent decrease in crude histidine decarboxylase (HDC) activity and gene expression of histidine decarboxylase (hdc). Molecular docking analysis demonstrated that CGA interacted with HDC through hydrogen bonds. Furthermore, in situ investigation confirmed the efficacy of CGA in controlling the growth of M. psychrotolerans and significantly reducing histamine formation in raw tuna. CGA had good activity in controlling the growth of M. psychrotolerans and histamine formation.

Exogenous methyl jasmonate promotes the biosynthesis of endogenous melatonin in mustard sprouts

The present study investigated the effects regulating melatonin (MT) biosynthesis under methyl jasmonate (MeJA) treatment in mustard sprouts. The results revealed that MeJA significantly increased the MT content in the sprouts to 11.43 times that of the control. However, MeJA treatment had an inhibitory effect on growth. Tryptophan decarboxylase and tryptamine 5-hydroxylase gene expression were significantly induced by MeJA. Moreover, 156 differential abundance proteins (DAPs) were detected in 4-day-old sprouts using quantitative proteomic methods. These DAPs were divided into 13 functional groups, and the vast majority of DAPs involved in defense/stress, energy, signal transduction, and secondary metabolism increased. MeJA treatment significantly enriched 15 pathways, including glutathione metabolism, biosynthesis of secondary metabolites, and tryptophan metabolism. In particular, the abundance of three DAPs (myrosinase 1, cytosolic sulfotransferase 16, and glutamate-glyoxylate aminotransferase 2) in the tryptophan metabolism pathway, a substrate for MT biosynthesis, increased significantly. In summary, MeJA induces endogenous MT biosynthesis in mustard sprouts by promoting the genes expression of MT synthetase and increasing the abundance of tryptophan-related proteins.

Lactobacillus delbrueckii reduces anxiety-like behavior in zebrafish through a gut microbiome – brain crosstalk

Certain bacteria possess the ability to reduce anxiety- and stress-related behaviors through the gut microbiome-brain axis. Such bacteria are called psychobiotics, and can be used to improve mood and cognition. However, only a few bacteria have been characterized as psychobiotics, and their exact mechanism of action remains unclear. Hence, in this study we analyzed three different species under the Lactobacillacea family, namely, Lactobacillus delbrueckii, Lacticaseibacillus casei, and Lacticaseibacillus paracasei for their potential psychobiotic activities. L. delbrueckii treatment reduced anxiety-like behavior and increased brain and gut glutamic acid decarboxylase (gad) gene expression in zebrafish. It also altered zebrafish gut microbial community as determined by PCR-DGGE and 16S rRNA-based metagenomics analysis. Overall, this paper showed that L. delbrueckii but not L. paracasei and L. casei, induced a consistent improvement in anxiety-like behavior in zebrafish, implicating its potential role as a psychobiotic to reduce anxiety.This article is part of the Special Issue on 'Microbiome & the Brain: Mechanisms & Maladies'.

Residue Analysis and the Effect of Preharvest Forchlorfenuron (CPPU) Application on On-Tree Quality Maintenance of Ripe Fruit in "Feizixiao" Litchi (Litchi chinensis Sonn.).

Litchi is a highly perishable fruit. Ripe litchi fruit loses quality quickly as they hang on tree, giving a very short hanging life and thus harvest period. This study attempted to explore the roles of cytokinin in regulating fruit ripening and senescence of litchi and examine the possibility of applying cytokinin in “on-tree storage” of the fruit. Exogenous cytokinin, forchlorfenuron (CPPU), was applied at 20 mg L−1 7 weeks after full bloom on litchi (Litchi chinensis cv. Feizixiao) fruit clusters. Color parameters, chlorophylls, anthocyanins, fruit and fruit part weights, total soluble solutes (TSSs), soluble sugars, organic acids, non-anthocyanin flavonoids, ethanol, and also CPPU residue in fruit were traced. CPPU residue was higher but decreased faster in the pericarp than in the aril, where it maintained < 10 μg kg−1. CPPU had no significant effect on fruit weight but tended to increase pericarp weight. The treatment suppressed chlorophyll loss and anthocyanin accumulation in the pericarp, increased non-anthocyanin flavonoids in the aril, but had no significant effects on non-anthocyanin flavonoids in the pericarp and total sugar and organic acids in the aril. As the commercially ripe fruit hanged on tree, TSSs, total sugar, and sucrose decreased with ethanol and acetic acid accumulation in the aril. CPPU significantly suppressed the loss of sucrose and total sugar and the accumulation of ethanol and acetic acid in the aril and inhibited malondialdehyde accumulation in the pericarp of the overripe fruit. Soluble invertase, alcohol dehydrogenase, and pyruvate decarboxylase (PDC) activity and gene expression in the aril were downregulated by CPPU. The results suggest that cytokinin partially suppresses the ripening process in litchi and is effective to slow quality loss in the overripe fruit on tree.

In vivo study of a novel protein kinase C that mediates immunocompetence and catecholamine biosynthesis in hemocytes of Litopenaeus vannamei by using its potential competitive inhibitor, bisindolylmaleimide I

This study applied bisindolylmaleimide I (BSM), a pharmacological competitive inhibitor of protein kinase C (PKC) enzymatic activity, at 1.25 pmol shrimp−1 for 60 min to investigate the potential involvement of PKC in signal transduction pathways in the hemocytes of Litopenaeus vannamei. A novel PKC in L. vannamei (LvnPKC) was identified and characterized and was determined to be involved in mediating the neuroendocrine-immune regulatory network. The hemocytes of L. vannamei that receive BSM exhibit significantly decreased PKC activity and LvnPKC gene and protein expression levels. Furthermore, the total hemocyte count, hyaline cells, and semigranular cells increased significantly along with significant decreases in granular cells, and meanwhile, the significantly increased phenoloxidase activity, respiratory bursts, superoxide dismutase (SOD) activity, phagocytic activity, and neutrophil extracellular trap were observed; however, phagocytic activity decreased significantly. In a molecular model, the gene expressions of lipopolysaccharide- and β-1,3-glucan-binding protein, peroxinectin, cytosolic manganese SOD, mitochondrial manganese SOD, and copper/zinc SOD in the hemocytes of L. vannamei that had received BSM decreased significantly, but prophenoloxidase I increased significantly. In catecholamine biosynthesis, tyrosine, dopamine, and norepinephrine decreased significantly in the hemocytes of L. vannamei that had received BSM, and l-dihydroxyphenylalanine increased. Moreover, tyrosine hydroxylase (TH) activity increased significantly, whereas TH and dihydroxyphenylalanine decarboxylase gene expression decreased significantly. These findings suggest that BSM inhibits PKC activity in hemocytes in which LvnPKC gene and protein expression are also inhibited. Additionally, the hemocytes’ immunocompetence, including their prophenoloxidase and antioxidant systems, phagocytic activity, and catecholamine biosynthesis, was disrupted, confirming the roles of LvnPKC in mediating the neuroendocrine-immune regulatory network in hemocytes.

The influence of laser beam and high light intensity on lentil (Lens culinaris) and wheat (Triticum aestivum) seedlings growth and metabolism

Light is considered as an environmental signal that controls plants growth and development. Sufficient duration, quality and wavelength are mainly responsible for switching on/off many physiological processes. The aim of this study was to examine the role of gamma aminobutyric acid (GABA) shunt pathway specific response in wheat (Triticum aestivum) and lentil (Lens culinaris) seedlings to blue LED laser (intensity= 1.48 W/cm2) and high intensity invisible ultraviolet light (intensity= 3.99 W/cm2) treatments separately, with respect to: seed germination, seedling growth, oxidative damage in term of reactive oxygen substances accumulation, GABA accumulation level, total proteins and total carbohydrates level and glutamate decarboxylase gene (GAD) expression. Data showed a remarkable changes in proteins content, carbohydrates content, chlorophyll level, dry and fresh weight, GABA accumulation, MDA level, and GAD m-RNA level under blue LED laser and high intensity invisible ultraviolet light treatments; separately in the both wheat and lentil cultivars. There were no significant differences of root emergence in all cultivars under all treatments. The concentrations of MDA increased in all cultivars under blue LED laser and high intensity invisible ultraviolet light treatments with increasing exposure durations. GABA levels increased and correlated significantly in all cultivars as the exposure duration of blue LED laser and high light intensity increased. Significant decrease in chlorophyll a and b contents in Um Qayes, Jordan1 and Jordan2 cultivars under all laser and high intensity invisible ultraviolet light treatments. A significant difference was found in proteins content in all cultivars in response to laser and high intensity invisible ultraviolet light treatments. Carbohydrates content in all cultivars used in this study were significantly decreased under laser treatments. The transcription level of GAD increased significantly under blue LED laser and high intensity invisible ultraviolet light in all cultivars used in this study. GAD expression was high in Hurani75 cultivar in agreement with the low level of GABA accumulation under high intensity invisible ultraviolet light at 60 min which strongly suggested that GABA was catabolized to enter another pathways (C:N balance) that was confirmed by increase in higher level of carbohydrates and proteins beside reduction in MDA content at the same exposure duration. On other hand, GAD expression in Jordan 2 was lower in response to laser treatment under the same exposure duration. The high increase of GAD gene expression explains the high accumulation of GABA level under both treatments. Results indicated that GABA shunt is a key metabolic pathway that allows wheat and lentil to adapt blue LED laser and high intensity invisible ultraviolet light stressful treatments.

Crosstalk between GABA and ALA to improve antioxidation and cell expansion of tomato seedling under cold stress

Cold stress inhibits plant growth and ultimately affects yield formation. Exogenous 5- aminolevulinic acid (ALA) can improve tomato cold tolerance and promote plant growth. It significantly up-regulated glutamate decarboxylase gene (SlGAD4) expression, which was involved in gamma-aminobutyric acid (GABA) synthesis. Whether the GABA was involved in ALA-regulated tomato cold tolerance and plant growth was unclear. Thus, this study aimed to explore the effects of exogenous ALA and GABA on endogenous ALA and GABA synthesis. The roles of ALA and GABA on regulating the antioxidation and cell morphological changes related to plant growth in tomato leaves were further explored. And the internal relationship between ALA and GABA in increasing tomato cold tolerance was also determined. Results showed that cold stress increased the glutamate (Glu) and GABA contents and reduced the ALA content. The exogenous ALA- or GABA-treated plants demonstrated decreased Glu content and increased GABA or ALA contents. Exogenous ALA or GABA treatment promoted the expansion of upper epidermal (UEP) and palisade parenchymal (PA) cells and up-regulated the xyloglucan endotransglucosylase/hydrolases gene (SlXTH23) expression in tomato leaves. Exogenous ALA or GABA significantly alleviated cold-induced tomato membrane lipid peroxidation and enhanced C-repeat binding factors gene (SlCBF2) expression and superoxide dismutase (SOD), catalase (CAT), APX and GR activities. Inhibiting endogenous GABA with 3-mercaptopropionic (3-mp) dramatically decreased the size of UEP and PA cells and reduced SOD and CAT activities. It also aggravated the membrane peroxidation damage, which notably weakened the alleviated effects of exogenous ALA. Inhibiting endogenous ALA with gabaculine (gaba) partly inhibited the alleviated effects of exogenous GABA. These findings indicated that spray with exogenous ALA or GABA could increase endogenous ALA and GABA levels in tomato leaves. In addition, endogenous GABA and ALA could be mutually converted through Glu. Exogenous ALA and GABA promoted cell expansion, stimulated the antioxidant system and might enhance tomato cold tolerance via endogenous GABA signal and the C-repeat binding factor regulation pathway, thereby alleviating cold inhibited plant growth. In conclusion, GABA crosstalk with ALA improved tomato cold stress tolerance and promoted plant growth by regulating antioxidants and cell expansion.

Ethanol and Cannabinoids Regulate Zebrafish GABAergic Neuron Development and Behavior in a Sonic Hedgehog and Fibroblast Growth Factor-Dependent Mechanism.

Ethanol (EtOH) has diverse effects on nervous system development, which includes development and survival of GABAergic neurons in a sonic hedgehog (Shh) and fibroblast growth factor (Fgf)-dependent mechanism. Cannabinoids also function as inhibitors of Shh signaling, raising the possibility that EtOH and cannabinoids may interact to broadly disrupt neuronal function during brain development. Zebrafish embryos were exposed to a range of EtOH and/or cannabinoid receptor 1 (CB1R) agonist concentrations at specific developmental stages, in the absence or presence of morpholino oligonucleotides that disrupt shh expression. In situ hybridization was employed to analyze glutamic acid decarboxylase (gad1) gene expression as a marker of GABAergic neuron differentiation, and zebrafish behavior was analyzed using the novel tank diving test as a measure of risk-taking behavior. Combined acute subthreshold EtOH and CB1R agonist exposure results in a marked reduction in gad1 mRNA expression in zebrafish forebrain. Consistent with the EtOH and cannabinoid effects on Shh signaling, fgf8 mRNA overexpression rescues the EtOH- and cannabinoid-induced decrease in gad1 gene expression and also prevents the changes in behavior induced by EtOH and cannabinoids. These studies provide evidence that forebrain GABAergic neuron development and zebrafish risk-taking behavior are sensitive to both EtOH and cannabinoid exposure in a Shh- and Fgf-dependent mechanism, and provide additional evidence that a signaling pathway involving Shh and Fgf crosstalk is a critical target of EtOH and cannabinoids in FASD.

Histamine Production Behaviors of a Psychrotolerant Histamine-Producer, Morganella psychrotolerans, in Various Environmental Conditions.

Histamine food poisoning is a major safety concern related to seafood consumption worldwide. Morganella psychrotolerans is a novel psychrotolerant histamine-producer. In this study, the histamine production behaviors of M. psychrotolerans and two other major histamine-producers, mesophilic Morganella morganii and psychrotrophic Photobacterium phosphoreum, were compared in seafood products, and histamine accumulation by M. psychrotolerans was characterized at various pH and temperature levels in culture broth. The growth of M. psychrotolerans and P. phosphoreum increased similarly at 4°C in canned tuna, but M. psychrotolerans produced much higher levels of histamine than P. phosphoreum. Histamine accumulation by M. psychrotolerans was induced at lower environmental pH condition at 4 and 20°C. The optimal temperature and pH for producing histamine by crude histidine decarboxylase of M. psychrotolerans were 30°C and pH 7, respectively. The activity of the crude HDC extracted from M. psychrotolerans cells at 10°C retained 45% of the activity at 30°C. Histidine decarboxylase gene expression of M. psychrotolerans was induced by low pH conditions. These results suggest that M. psychrotolerans are also a very important histamine-producer leading to histamine poisoning associated with seafood below the refrigeration temperature.

Peroxisome proliferator-activated receptor α agonist-induced histidine decarboxylase gene expression in the rat and mouse liver.

By analysis of the data from the Toxicogenomics Database (TG-GATEs), histidine decarboxylase gene (Hdc) was identified as largely and commonly upregulated by three fibrates, clofibrate, fenofibrate, and WY-14,643, which are known to induce hepatocellular hypertrophy and proliferation via stimulation of peroxisome proliferator-activated receptor α (PPARα) in rodents. As histamine has been reported to be involved in the proliferation of liver cells, the present study was conducted to focus on Hdc. Among other genes related to histidine and histamine, the expression of the gene of histamine ammonia lyase (Hal) was exclusively mobilized by the three fibrates. The expression of Hdc, which was usually very low in the liver, was increased with the repeated administration of fibrates, and concomitantly, the constitutive expression of Hal was suppressed. An interpretation is that the formation of urocanic acid from histidine under the normal condition switches to the formation of histamine. The mobilization of gene expression of Hdc and Hal by PPARα agonists could not be reproduced in primary cultured hepatocytes. The Hdc mRNA appeared to be translated to a protein which is processed differently from brain but similarly to gastric mucosa. Surprisingly, the fibrates caused hepatic hypertrophy but no induction of Hdc mRNA at all in mice. These results revealed that the changes in the histidine catabolism by PPARα agonists might be partially, but not directly, involved in the hepatocyte proliferation in rats, and there is a large genetic distance even between rat and mouse.

Redox-Regulation of Photorespiration through Mitochondrial Thioredoxin o1.

Photorespiration sustains photosynthesis in the presence of oxygen due to rapid metabolization of 2-phosphoglycolate, the major side-product of the oxygenase activity of Rubisco that also directly impedes carbon assimilation and allocation. Despite the fact that both the biochemical reactions and the underlying genetics are well characterized, information concerning the regulatory mechanisms that adjust photorespiratory flux is rare. Here, we studied the impact of mitochondrial-localized thioredoxin o1 (TRXo1) on photorespiratory metabolism. The characterization of an Arabidopsis (Arabidopsis thaliana) transfer DNA insertional line (trxo1-1) revealed an increase in the stoichiometry of photorespiratory CO2 release and impaired Gly-to-Ser turnover after a shift from high-to-low CO2 without changes in Gly decarboxylase (GDC) gene or protein expression. These effects were distinctly pronounced in a double mutant, where the TRXo1 mutation was combined with strongly reduced GDC T-protein expression. The double mutant (TxGT) showed reduced growth in air but not in high CO2, decreased photosynthesis, and up to 54-fold more Gly alongside several redox-stress-related metabolites. Given that GDC proteins are potential targets for redox-regulation, we also examined the in vitro properties of recombinant GDC l-proteins (lipoamide dehydrogenase) from plants and the cyanobacterium Synechocystis species strain PCC6803 and observed a redox-dependent inhibition by either artificial reducing agents or TRXo1 itself. Collectively, our results demonstrate that TRXo1 potentially adjusts photorespiration via redox-regulation of GDC in response to environmental changes.

Influence of arginine on enzymes related to arginine metabolism in bovine mammary epithelial cells in vitro

Bovine mammary epithelial cells were used to evaluate the effects of different levels of Arginine (Arg) on enzymes related to Arg metabolism. A series of seven Arg concentrations in the medium as treatments were T0 (0.00 mg L−1) as control group, and T0.25 (69.50 mg L−1), T0.5 (139.00 mg L−1), T1 (278.00 mg L−1), T2 (556.00 mg L−1), T4 (1112.00 mg L−1), and T8 (2224.00 mg L−1) as experiment groups, respectively. The quantitative polymerase chain reaction and enzyme-linked immunosorbent assay analysis showed that the nitric oxide concentration, the expressions of endothelial nitric oxide synthase in mRNA, and enzyme level were all increased in response to enhanced Arg doses such that the T8 was the greatest group (P &lt; 0.05). Four-fold Arg concentration improved gene expression and synthesis of arginase which then deceased when excessive Arg was supplied (P &lt; 0.05). The expressions of ornithine aminotransferase mRNA and enzyme in T1 and T2 groups were significantly greater than that in the other groups (P &lt; 0.05). Two-fold Arg was the optimum level for ornithine decarboxylase gene expression and enzyme synthesis among all seven treatments (P &lt; 0.05). These somewhat various effects of Arg concentrations on four kinds of enzymes in different Arg metabolic pathways suggest that Arg might participate in regulating bovine mammary physiological function with an optimum concentration by influencing the enzymes in related metabolic pathways.

Down-regulation of arginine decarboxylase gene-expression results in reactive oxygen species accumulation in Arabidopsis

Arabidopsis amiR:ADC-L2 is a non-lethal line with several developmental defects, it is characterized by a drastic reduction in free polyamine content. Herein, we found that catalase application had growth-promoting effects in amiR:ADC-L2 and parental Ws seedlings. Differences in ROS content between amiR:ADC-L2 and Ws seedlings were detected. Increased H2O2 levels were found in the amiR:ADC-L2, as well as low AtCAT2 gene expression and reduced catalase activity. Estimation of polyamine oxidase activity in amiR:ADC-L2 line indicated that the over-accumulation of H2O2 is independent of polyamine catabolism. However, increments in NADPH oxidase activity and O2•− content could be associated to the higher H2O2 levels in the amiR:ADC-L2 line. Our data suggest that low polyamine levels in Arabidopsis seedlings are responsible for the accumulation of ROS, by altering the activities of enzymes involved in ROS production and detoxification.

Urtica dioica inhibits cell growth and induces apoptosis by targeting Ornithine decarboxylase and Adenosine deaminase as key regulatory enzymes in adenosine and polyamines homeostasis in human breast cancer cell lines

Breast cancer is a heterogeneous and multifactorial disease with variable disease progression risk, and treatment response. Urtica dioica is a traditional herb used as an adjuvant therapeutic agent in cancer. In the present study, we have evaluated the effects of the aqueous extract of Urtica dioica on Adenosine deaminase (ADA) and Ornithine decarboxylase (ODC1) gene expression in MCF-7, MDA-MB-231, two breast cancer cell lines being estrogen receptor positive and estrogen receptor negative, respectively. Cell lines were cultured in suitable media. After 24 h, different concentrations of the extract were added and after 72 h, ADA and ODC1 gene expression as well as BCL2 and BAX apoptotic genes were assessed by Taqman real time PCR assay. Cells viability was assessed by MTT assay, and apoptosis was also evaluated at cellular level. The intra and extracellular levels of ODC1 and ADA enzymes were evaluated by ELISA. Results showed differential expression of ADA and ODC1 genes in cancer cell lines. In MCF-7 cell line, the expression level of ADA was upregulated in a dose-dependent manner but its expression did not change in MDA-MB cell line. ODC1 expression was increased in both examined cell lines. Also, increased level of the apoptotic BAX/BCL-2 ratio was detected in MCF-7 cells. These results demonstrated that Urtica dioica induces apoptosis in breast cancer cells by influencing ODC1 and ADA genes expression, and estrogen receptors. The different responses observed with these cell lines could be due to the interaction of Urtica dioica as a phytoestrogen with the estrogen receptor.

Plant-endophytes interaction influences the secondary metabolism in Echinacea purpurea (L.) Moench: an in vitro model

The influence of the interaction(s) between the medicinal plant Echinacea purpurea (L.) Moench and its endophytic communities on the production of alkamides is investigated. To mimic the in vivo conditions, we have set up an infection model of axenic in vitro E. purpurea plants inoculated with a pool of bacterial strains isolated from the E. purpurea stems and leaves. Here we show different alkamide levels between control (not-inoculated) and inoculated plants, suggesting that the alkamide biosynthesis may be modulated by the bacterial infection. Then, we have analysed the branched-chain amino acids (BCCA) decarboxylase gene (GenBank Accession #LT593930; the enzymatic source for the amine moiety formation of the alkamides) expression patterns. The expression profile shows a higher expression level in the inoculated E. purpurea tissues than in the control ones. These results suggest that the plant-endophyte interaction can influence plant secondary metabolism affecting the therapeutic properties of E. purpurea.

Characterization of the Polyamine Biosynthetic Pathways and Salt Stress Response in Brachypodium distachyon

To characterize polyamine (PA) biosynthetic pathways in Brachypodium distachyon, we analyzed the gene-expression patterns and PA contents in various organs. Three major PAs—putrescine (Put), spermidine (Spd), and spermine (Spm)—were detected, but thermospermine (T-Spm) was below the sensitivity limit of high-performance liquid chromatography in all tissues examined, although expression of the ACL5 gene, which is known as the T-Spm synthesis gene, was confirmed. In leaves, Put was the most abundant PA, and its level of accumulation was more than three times greater than those of Spd and Spm. In contrast, the primary PA in other organs was Spd. A high correlation was observed between arginine decarboxylase (ADC) gene-expression patterns and Put contents under normal growth conditions. These results indicate that Put is normally synthesized through the ADC pathway. We also analyzed salt stress responses and confirmed that all PA biosynthesis genes are induced by NaCl treatment. Moreover, Spm highly accumulated under salt stress conditions. Recently, T-Spm was shown to enhance the translation of Arabidopsis SAC51 family mRNAs, at least SAC51 and SACL1, by reducing the inhibitory effect of the conserved upstream open reading frame (uORF). Through database analysis, three and five SAC51 family genes were identified from B. distachyon and Zea mays, respectively. However, these genes are most closely related to SACL3 in Arabidopsis, and the commonly conserved uORF sequence was not confirmed for some of these genes. Therefore, the function of T-Spm in monocotyledonous plant species might be different from that in Arabidopsis.

Basophils, high-affinity IgE receptors, and CCL2 in human anaphylaxis

BackgroundThe role of basophils in anaphylaxis is unclear.ObjectiveWe sought to investigate whether basophils have an important role in human anaphylaxis.MethodsIn an emergency department study we recruited 31 patients with acute anaphylaxis, predominantly to Hymenoptera venom. We measured expression of basophil activation markers (CD63 and CD203c); the absolute number of circulating basophils; whole-blood FCER1A, carboxypeptidase A3 (CPA3), and L-histidine decarboxylase (HDC) gene expression; and serum markers (CCL2, CCL5, CCL11, IL-3, and thymic stromal lymphopoietin) at 3 time points (ie, during the anaphylactic episode and in convalescent samples 7 and 30 days later). We recruited 134 patients with Hymenoptera allergy and 76 healthy control subjects for comparison. We then investigated whether the changes observed during venom-related anaphylaxis also occur during allergic reactions to food in 22 patients with peanut allergy undergoing double-blind, placebo-controlled food challenge to peanut.ResultsThe number of circulating basophils was significantly lower during anaphylaxis (median, 3.5 cells/μL) than 7 and 30 days later (17.5 and 24.7 cells/μL, P < .0001) and compared with those in patients with venom allergy and healthy control subjects (21 and 23.4 cells/μL, P < .0001). FCER1A expression during anaphylaxis was also significantly lower than in convalescent samples (P ≤ .002) and control subjects with venom allergy (P < .0001). CCL2 levels (but not those of other serum markers) were significantly higher during anaphylaxis (median, 658 pg/mL) than in convalescent samples (314 and 311 pg/mL at 7 and 30 days, P < .001). Peanut-induced allergic reactions resulted in a significant decrease in circulating basophil counts compared with those in prechallenge samples (P = .016), a decrease in FCER1A expression (P = .007), and an increase in CCL2 levels (P = .003).ConclusionsOur findings imply an important and specific role for basophils in the pathophysiology of human anaphylaxis.

Ornithine decarboxylase gene expression and activity in lung cancer

Lung cancer is the malignant tumor of highest mortality rate in men worldwide, and its rate is increasing in women. Ornithine decarboxylase (ODC) is the first enzyme in the pathway of polyamines synthesis and its expression was found increased in many types of tumor tissues. This investigation aimed at measuring ODC activity and gene expression in patients with non-small cell lung cancer (NSCLC). 3 different histopathologic types were included; adenocarcinoma (AC), squamous lung carcinoma (SCC) and large cell lung carcinoma (LCC). The patients were at stages I or II and undergone curative tumor resection. The study revealed that, ODC gene expression and activity were significantly elevated in tumor tissue compared to benign tissue (P<0.0001). In tumor tissues from patients with adenocarcinoma and large cell carcinoma ODC had a higher genetic expression level and activity than in tumor tissues from patients with squamous cell carcinoma (P<0.05). We concluded that ODC may have a clinical and prognostic significance regarding the type and severity of tumor in patients with NSCLC.

Tyrosine decarboxylase activity of Enterococcus mundtii: new insights into phenotypic and genetic aspects.

SummaryFew information is available about the tyraminogenic potential of the species Enterococcus mundtii. In this study, two plant‐derived strains of E. mundtii were selected and investigated to better understand the phenotypic behaviour and the genetic mechanisms involved in tyramine accumulation. Both the strains accumulated tyramine from the beginning of exponential phase of growth, independently on the addition of tyrosine to the medium. The strains accumulated also 2‐phenylethylamine, although with lower efficiency and in greater extent when tyrosine was not added. Accordingly, the tyrosine decarboxylase (tyrDC) gene expression level increased during the exponential phase with tyrosine added, while it remained constant and high without precursor. The genetic organization as well as sequence identity levels of tyrDC and tyrosine permease (tyrP) genes indicated a correlation with those of phylogenetically closer enterococcal species, such as E. faecium, E. hirae and E. durans; however, the gene Na+/H+ antiporter (nhaC) that usually follow tyrP is missing. In addition, BLAST analysis revealed the presence of additional genes encoding for decarboxylase and permease in the genome of several E. mundtii strains. It is speculated the occurrence of a duplication event and the acquisition of different specificity for these enzymes that deserves further investigations.

Antihistamines suppress upregulation of histidine decarboxylase gene expression with potencies different from their binding affinities for histamine H1 receptor in toluene 2,4-diisocyanate-sensitized rats

Antihistamines inhibit histamine signaling by blocking histamine H1 receptor (H1R) or suppressing H1R signaling as inverse agonists. The H1R gene is upregulated in patients with pollinosis, and its expression level is correlated with the severity of nasal symptoms. Here, we show that antihistamine suppressed upregulation of histidine decarboxylase (HDC) mRNA expression in patients with pollinosis, and its expression level was correlated with that of H1R mRNA. Certain antihistamines, including mepyramine and diphenhydramine, suppress toluene-2,4-diisocyanate (TDI)-induced upregulation of HDC gene expression and increase HDC activity in TDI-sensitized rats. However, d-chlorpheniramine did not demonstrate any effect. The potencies of antihistamine suppressive effects on HDC mRNA elevation were different from their H1R receptor binding affinities. In TDI-sensitized rats, the potencies of antihistamine inhibitory effects on sneezing in the early phase were related to H1R binding. In contrast, the potencies of their inhibitory effects on sneezing in the late phase were correlated with those of suppressive effects on HDC mRNA elevation. Data suggest that in addition to the antihistaminic and inverse agonistic activities, certain antihistamines possess additional properties unrelated to receptor binding and alleviate nasal symptoms in the late phase by inhibiting synthesis and release of histamine by suppressing HDC gene transcription.