Copper-containing diamine oxidases are ubiquitous enzymes that participate in many important biological processes. These processes include the regulation of cell growth and division, programmed cell death, and responses to environmental stressors. Natural substrates include, for example, putrescine, spermidine, and histamine. Enzymatic activity is typically assayed using spectrophotometric, electrochemical, or fluorometric methods. The aim of this study was to develop a method for measuring activity using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry based on the intensity ratio of product to product-plus-substrate signals in the reaction mixtures. For this purpose, an enzyme purified to homogeneity from pea (Pisum sativum) seedlings was used. The method employed α-cyano-4-hydroxycinnamic acid as a matrix with the addition of cetrimonium bromide. Product signal intensities with pure compounds were evaluated in the presence of equal substrate amounts to determine intensity correction factors for data processing calculations. The kinetic parameters kcat and Km for the oxidative deamination of selected substrates were determined. These results were compared to parallel measurements using an established spectrophotometric method, which involved a coupled reaction of horseradish peroxidase and guaiacol, and were discussed in the context of data from the literature and the BRENDA database. It was found that the method provides accurate results that are well comparable with parallel spectrophotometry. This method offers advantages such as low sample consumption, rapid serial measurements, and potential applicability in assays where colored substances interfere with spectrophotometry.

• Klíčová slova
• MALDI, activity assay, amine oxidase, enzyme kinetics, polyamine, reaction rate,
• MeSH
• enzymatické testy metody   MeSH
• histaminasa * metabolismus   chemie   MeSH
• hrách setý enzymologie   chemie   MeSH
• kinetika MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice * metody   MeSH
• substrátová specifita MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• histaminasa * MeSH

Putrescine (Put) is a promising small molecule-based biostimulant to enhance plant growth and resilience, though its mode of action remains unclear. This study investigated the Put priming effect on Arabidopsis mutant lines (Atadc1, Atadc2, Atnata1, and Atnata2) under control conditions and salinity to understand its role in regulating plant growth. The Atadc2 mutant, characterized by reduced endogenous Put levels, showed insensitivity to Put priming without growth enhancement, which was linked to significant imbalances in nitrogen metabolism, including a high Gln/Glu ratio. Contrarily, the Atnata2 mutant exhibited significant growth improvement and upregulated AtADC2 expression, particularly under Put priming, highlighting these genes' involvement in regulating plant development. Put priming enhanced plant growth by inducing the accumulation of specific polyamines (free, acetylated, conjugated, or bound form) and improving light-harvesting efficiency, particularly in the Atnata2 line. Our findings suggest that AtNATA2 may negatively regulate Put synthesis and accumulation via AtADC2 in the chloroplast, impacting light harvesting in photosystem II (PSII). Furthermore, the Atadc2 mutant line exhibited upregulated AtADC1 but reduced AcPut levels, pointing to a cross-regulation among these genes. The regulation by AtNATA2 on AtADC2 and AtADC2 on AtADC1 could be crucial for plant growth and overall stress tolerance by interacting with polyamine catabolism, which shapes the plant metabolic profile under different growth conditions. Understanding the regulatory mechanisms involving crosstalk between AtADC and AtNATA genes in polyamine metabolism and the connection with certain SMBBs like Put can lead to more effective agricultural practices, improving plant growth, nitrogen uptake, and resilience under challenging conditions.

• MeSH
• Arabidopsis * genetika   růst a vývoj   fyziologie   metabolismus   MeSH
• fotosystém II (proteinový komplex) metabolismus   MeSH
• mutace ztráty funkce MeSH
• polyaminy metabolismus   MeSH
• proteiny huseníčku * genetika   metabolismus   MeSH
• putrescin * metabolismus   MeSH
• regulace genové exprese u rostlin * MeSH
• tolerance k soli * genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fotosystém II (proteinový komplex) MeSH
• polyaminy MeSH
• proteiny huseníčku * MeSH
• putrescin * MeSH

Red light promotes germination after activating phytochrome phyB, which destabilizes the germination repressor PIF1. Early upon seed imbibition, canopy light, unfavorable for photosynthesis, represses germination by stabilizing PIF1 after inactivating phyB. Paradoxically, later upon imbibition, canopy light stimulates germination after activating phytochrome phyA. phyA-mediated germination is poorly understood and, intriguingly, is inefficient, compared to phyB-mediated germination, raising the question of its physiological significance. A genetic screen identified polyamine uptake transporter 2 (put2) mutants that overaccumulate polyamines, a class of antioxidant polycations implicated in numerous cellular functions, which we found promote phyA-mediated germination. In WT seeds, our data suggest that canopy light represses polyamines accumulation through PIF1 while red light promotes polyamines accumulation. We show that canopy light also downregulates PIF1 levels, through phyA; however, PIF1 reaccumulates rapidly, which limits phyA-mediated germination. High polyamines levels in decaying seeds bypass PIF1 repression of germination and stimulate phyA-mediated germination, suggesting an adaptive mechanism promoting survival when viability is compromised.

• MeSH
• 1-pyrrolin-5-karboxylátdehydrogenasa genetika   metabolismus   MeSH
• Arabidopsis růst a vývoj   metabolismus   MeSH
• down regulace MeSH
• fytochrom A metabolismus   MeSH
• klíčení MeSH
• mutace MeSH
• polyaminy metabolismus   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• světlo MeSH
• transkripční faktory bHLH metabolismus   MeSH
• transportní systémy aminokyselin genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-pyrrolin-5-karboxylátdehydrogenasa MeSH
• fytochrom A MeSH
• PIF1 protein, Arabidopsis MeSH Prohlížeč
• polyaminy MeSH
• proteiny huseníčku MeSH
• PUT2 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny MeSH
• transkripční faktory bHLH MeSH
• transportní systémy aminokyselin MeSH

Reactive oxygen species (ROS) have been recognized as important signaling compoundsof major importance in a number of developmental and physiological processes in plants. Theexistence of cellular compartments enables efficient redox compartmentalization and ensuresproper functioning of ROS-dependent signaling pathways. Similar to other organisms, theproduction of individual ROS in plant cells is highly localized and regulated bycompartment-specific enzyme pathways on transcriptional and post-translational level. ROSmetabolism and signaling in specific compartments are greatly affected by their chemicalinteractions with other reactive radical species, ROS scavengers and antioxidant enzymes. Adysregulation of the redox status, as a consequence of induced ROS generation or decreasedcapacity of their removal, occurs in plants exposed to diverse stress conditions. During stresscondition, strong induction of ROS-generating systems or attenuated ROS scavenging can lead tooxidative or nitrosative stress conditions, associated with potential damaging modifications of cellbiomolecules. Here, we present an overview of compartment-specific pathways of ROS productionand degradation and mechanisms of ROS homeostasis control within plant cell compartments.

• Klíčová slova
• cell wall, chloroplasts, cytoplasmic membrane, cytosol, glyoxysomes, mitochondria, peroxisomes, plant cell, reactive oxygen species,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Hydrogen peroxide (H₂O₂) is steadily gaining more attention in the field of molecular biology research. It is a major REDOX (reduction⁻oxidation reaction) metabolite and at high concentrations induces oxidative damage to biomolecules, which can culminate in cell death. However, at concentrations in the low nanomolar range, H₂O₂ acts as a signalling molecule and in many aspects, resembles phytohormones. Though its signalling network in plants is much less well characterized than are those of its counterparts in yeast or mammals, accumulating evidence indicates that the role of H₂O₂-mediated signalling in plant cells is possibly even more indispensable. In this review, we summarize hydrogen peroxide metabolism in plants, the sources and sinks of this compound and its transport via peroxiporins. We outline H₂O₂ perception, its direct and indirect effects and known targets in the transcriptional machinery. We focus on the role of H₂O₂ in plant growth and development and discuss the crosstalk between it and phytohormones. In addition to a literature review, we performed a meta-analysis of available transcriptomics data which provided further evidence for crosstalk between H₂O₂ and light, nutrient signalling, temperature stress, drought stress and hormonal pathways.

• Klíčová slova
• H2O2, growth and development, plant hormone, signalling, stress,
• MeSH
• biologický transport MeSH
• fyziologický stres MeSH
• peroxid vodíku metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin genetika   metabolismus   MeSH
• rostliny genetika   metabolismus   MeSH
• signální transdukce * MeSH
• transkriptom MeSH
• vývoj rostlin * MeSH
• Publikační typ
• časopisecké články MeSH
• metaanalýza MeSH
• přehledy MeSH
• Názvy látek
• peroxid vodíku MeSH
• regulátory růstu rostlin MeSH