Tyramine is one of the most toxic biogenic amines and it is produced commonly by lactic acid bacteria in fermented food products. In present study, we investigated the influence of selected nisin-producing Lactococcus lactis subsp. lactis strains and their cell-free supernatants (CFSs) on tyramine production by four Lactobacillus and two Lactiplantibacillus strains isolated from cheese and beer. Firstly, we examined the antimicrobial effect of the CFSs from twelve Lactococcus strains against tested tyramine producers by agar-well diffusion assay. Six Lactococcus strains whose CFSs showed the highest antimicrobial effect on tyramine producers were further studied. Secondly, we investigated the influence of the selected six Lactococcus strains and their respective CFSs on tyramine production by tested Lactobacillus and Lactiplantibacillus strains in MRS broth supplemented with 2 g.L-1 of l-tyrosine. Tyramine production was monitored by HPLC-UV. The tyramine formation of all tested Lactobacillus and Lactiplantibacillus strains was not detected in the presence of Lc. lactis subsp. lactis CCDM 71 and CCDM 702, and their CFSs. Moreover, the remainder of the investigated Lactococcus strains (CCDM 670, CCDM 686, CCDM 689 and CCDM 731) and their CFSs decreased tyramine production significantly (P < 0.05) - even suppressing it completely in some cases - in four of the six tested tyramine producing strains.
- Klíčová slova
- Cell-free supernatants, Fermented food, Lactic acid bacteria, Lactiplantibacillus plantarum, Lactobacillus strains, Nisin, Tyramine,
- MeSH
- antibakteriální látky analýza metabolismus farmakologie MeSH
- kultivační média chemie metabolismus farmakologie MeSH
- Lactobacillaceae účinky léků růst a vývoj izolace a purifikace MeSH
- Lactobacillus účinky léků růst a vývoj izolace a purifikace MeSH
- Lactococcus lactis chemie metabolismus MeSH
- pivo mikrobiologie MeSH
- sýr mikrobiologie MeSH
- tyramin analýza metabolismus farmakologie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antibakteriální látky MeSH
- kultivační média MeSH
- tyramin MeSH
AIMS: The goal of our study was to reveal the important mechanism(s) responsible for the enhanced contractility of isolated arteries from animals suffering genetic hypertension. MAIN METHODS: Contractile force of endothelium-denuded arteries, modulated by various interventions, was measured by wire myography. KEY FINDINGS: Spontaneously hypertensive rat (SHR) and Wistar-Kyoto rat (WKY) arteries were stimulated by norepinephrine, increased extracellular K+ or tyramine. Strain difference was not observed in the contraction elicited by exogenous norepinephrine but SHR arteries responded more to tyramine (causing endogenous norepinephrine release from neuronal varicosities). K+-induced contraction was enhanced in SHR arteries, with no involvement of endogenous catecholamines. The α-adrenoceptor blockade lowered tyramine-induced contraction more in SHR arteries; similar effect was achieved by guanethidine-induced sympathectomy. Partial depolarization of WKY arteries by 20mM K+ enhanced its contraction to SHR level. The blockade of β-adrenoceptors by propranolol or selective β2-antagonist ICI-118,551 induced contraction of SHR endothelium-denuded arteries but was without significant effects on WKY arteries unless they were stimulated with K+. Both tyramine-induced and propranolol-induced contractions were attenuated by flupirtine and abolished by nifedipine. SIGNIFICANCE: The differences of SHR and WKY arteries were not related to vascular expression of α- and β-adrenoceptors or G-proteins. Enhanced contractility of SHR arteries is related to both increased presence of endogenous norepinephrine in vascular wall and also to altered vascular smooth muscle membrane potential.
- Klíčová slova
- Adrenergic contraction, Femoral artery, Neuropeptide Y, Propranolol, SHR, Tyramine, Vascular contractility,
- MeSH
- arterie fyziologie MeSH
- draslík metabolismus MeSH
- hypertenze MeSH
- membránové potenciály MeSH
- noradrenalin metabolismus MeSH
- potkani inbrední SHR fyziologie MeSH
- potkani inbrední WKY MeSH
- svalová kontrakce MeSH
- svaly hladké cévní fyziologie MeSH
- tyramin metabolismus MeSH
- vazokonstrikce * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- draslík MeSH
- noradrenalin MeSH
- tyramin MeSH
Tau protein in cerebrospinal fluid (CSF) is an important biomarker of Alzheimer's disease and some other brain diseases. Enzyme-linked immunosorbent assays (ELISAs) have been mostly used for quantification of tau and other biomarkers in CSF. However, these assays do not have sufficient sensitivity and dynamic range. In this study we tested the suitability of gold nanoparticles functionalized with tau-specific monoclonal antibody and oligonucleotide template for immuno-polymerase chain reaction (Nano-iPCR) quantification of tau protein in human CSF samples and compared it with ELISA, either commercial or newly developed with tyramide signal amplification. Our data indicate that Nano-iPCR is superior in sensitivity and detection range to ELISA in tau protein detection.
- Klíčová slova
- ELISA, Gold nanoparticles, PCR, Tau protein,
- MeSH
- Alzheimerova nemoc diagnóza MeSH
- biologické markery mozkomíšní mok MeSH
- ELISA * MeSH
- kovové nanočástice * MeSH
- lidé MeSH
- monoklonální protilátky imunologie MeSH
- polymerázová řetězová reakce metody MeSH
- proteiny tau mozkomíšní mok MeSH
- senzitivita a specificita MeSH
- tyramin metabolismus MeSH
- zlato * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- biologické markery MeSH
- MAPT protein, human MeSH Prohlížeč
- monoklonální protilátky MeSH
- proteiny tau MeSH
- tyramin MeSH
- zlato * MeSH
Ala and Gly substitutions for Pro 101 (P101) located in transmembrane domain 2 of the dopamine transporter (DAT) abolished transport activity but did not disrupt plasma membrane expression. Due to the high conservation of P101 in all neurotransmitter transporters and the capability of Pro to add flexibility to helices, we hypothesized that P101 contributes to the dynamic feature of substrate translocation. To test this hypothesis, here we analysed transport activity for DAT mutants where this Pro was mutated into different amino acids, including Ser, Val, Leu and Phe. The transmembrane domain 2 helix of P101F, unlike the other mutants, was computationally predicted to have a Van der Waals energy threefold higher than the wild-type helix. P101F mutant expression was consistently disrupted in COS cells. Among all the other mutants that express normally, P101V, with a side-chain size close to that of Pro, restores the transport activity of P101A by sevenfold. Most importantly, P101V, P101L and P101S display negative-dosage effects on dopamine (DA) transport, i.e. the velocity-concentration curve for DA uptake does not show a plateau with increasing [DA] but rather peaks and then goes down. These data support the view that P101 of DAT plays an essential role in DA translocation.
- MeSH
- Cercopithecus aethiops MeSH
- COS buňky MeSH
- dopamin metabolismus MeSH
- inhibitory vychytávání dopaminu metabolismus MeSH
- kokain analogy a deriváty metabolismus MeSH
- membránové glykoproteiny chemie genetika metabolismus MeSH
- membránové transportní proteiny chemie genetika metabolismus MeSH
- mutageneze cílená * MeSH
- prolin chemie genetika MeSH
- proteiny nervové tkáně chemie genetika metabolismus MeSH
- proteiny přenášející dopamin přes plazmatickou membránu MeSH
- substituce aminokyselin genetika MeSH
- termodynamika MeSH
- tyramin metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, P.H.S. MeSH
- srovnávací studie MeSH
- Názvy látek
- (1R-(exo,exo))-3-(4-fluorophenyl)-8-methyl-8- azabicyclo(3.2.1)octane-2-carboxylic acid, methyl ester MeSH Prohlížeč
- dopamin MeSH
- inhibitory vychytávání dopaminu MeSH
- kokain MeSH
- membránové glykoproteiny MeSH
- membránové transportní proteiny MeSH
- prolin MeSH
- proteiny nervové tkáně MeSH
- proteiny přenášející dopamin přes plazmatickou membránu MeSH
- tyramin MeSH
