- MeSH
- bakteriální proteiny * genetika MeSH
- beta-laktamasy * genetika analýza MeSH
- laktony metabolismus MeSH
- lidé MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- dopisy MeSH
Structural knowledge of biological macromolecules is essential for understanding their function and for modifying that function by engineering. Protein crystallography is a powerful method for elucidating molecular structures of proteins, but it is essential that the investigator has a basic knowledge of good practices and of the major pitfalls in the technique. Here we describe issues specific for the case of structural studies of strigolactone (SL) receptor structure and function, and in particular the difficulties associated with capturing complexes of SL receptors with the SL hormone ligand in the crystal.
- MeSH
- heterocyklické sloučeniny tricyklické metabolismus MeSH
- konformace proteinů MeSH
- krystalografie rentgenová MeSH
- laktony metabolismus MeSH
- ligandy MeSH
- molekulární modely MeSH
- receptory buněčného povrchu genetika metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné proteiny genetika metabolismus MeSH
- signální transdukce MeSH
- vazba proteinů MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Directional transport of the phytohormone auxin is a versatile, plant-specific mechanism regulating many aspects of plant development. The recently identified plant hormones, strigolactones (SLs), are implicated in many plant traits; among others, they modify the phenotypic output of PIN-FORMED (PIN) auxin transporters for fine-tuning of growth and developmental responses. Here, we show in pea and Arabidopsis that SLs target processes dependent on the canalization of auxin flow, which involves auxin feedback on PIN subcellular distribution. D14 receptor- and MAX2 F-box-mediated SL signaling inhibits the formation of auxin-conducting channels after wounding or from artificial auxin sources, during vasculature de novo formation and regeneration. At the cellular level, SLs interfere with auxin effects on PIN polar targeting, constitutive PIN trafficking as well as clathrin-mediated endocytosis. Our results identify a non-transcriptional mechanism of SL action, uncoupling auxin feedback on PIN polarity and trafficking, thereby regulating vascular tissue formation and regeneration.
- MeSH
- Arabidopsis genetika metabolismus MeSH
- heterocyklické sloučeniny tricyklické metabolismus MeSH
- hrách setý genetika metabolismus MeSH
- kyseliny indoloctové metabolismus MeSH
- laktony metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin genetika fyziologie MeSH
- regulátory růstu rostlin metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The luxS gene is responsible for the synthesis of AI-2 (autoinducer-2), a signaling molecule that participates in quorum sensing regulation in a large number of bacteria. In this work, we investigated which phenotypes are regulated by luxS gene in Serratia proteamaculans 94, psychrotrophic strain isolated from spoiled refrigerated meat. AI-2 was identified in S. proteamaculans 94, and the luxS gene involved in its synthesis was cloned and sequenced. A mutant with the inactivated luxS gene was constructed. Inactivation of the luxS gene was shown to lead to the absence of AI-2 synthesis, chitinolytic activity, swimming motility, suppression of the growth of fungal plant pathogens Rhizoctonia solani and Helminthosporium sativum by volatile compounds emitted by S. proteamaculans 94 strain, and to a decrease of extracellular proteolytic activity. The knockout of the luxS gene did not affect synthesis of N-acyl-homoserine lactones, lipolytic, and hemolytic activities of S. proteamaculans 94.
- MeSH
- bakteriální proteiny genetika MeSH
- biofilmy růst a vývoj MeSH
- fenotyp MeSH
- homoserin analogy a deriváty metabolismus MeSH
- laktony metabolismus MeSH
- lyasy štěpící vazby C-S genetika MeSH
- maso mikrobiologie MeSH
- mikrobiální interakce MeSH
- quorum sensing genetika MeSH
- regulace genové exprese u bakterií MeSH
- Serratia genetika metabolismus MeSH
- těkavé organické sloučeniny analýza MeSH
- umlčování genů * MeSH
- Publikační typ
- časopisecké články MeSH
Strigolactones (SLs) are a relatively recent addition to the list of plant hormones that control different aspects of plant development. SL signalling is perceived by an α/β hydrolase, DWARF 14 (D14). A close homolog of D14, KARRIKIN INSENSTIVE2 (KAI2), is involved in perception of an uncharacterized molecule called karrikin (KAR). Recent studies in Arabidopsis identified the SUPPRESSOR OF MAX2 1 (SMAX1) and SMAX1-LIKE 7 (SMXL7) to be potential SCF-MAX2 complex-mediated proteasome targets of KAI2 and D14, respectively. Genetic studies on SMXL7 and SMAX1 demonstrated distinct developmental roles for each, but very little is known about these repressors in terms of their sequence features. In this study, we performed an extensive comparative analysis of SMXLs and determined their phylogenetic and evolutionary history in the plant lineage. Our results show that SMXL family members can be sub-divided into four distinct phylogenetic clades/classes, with an ancient SMAX1. Further, we identified the clade-specific motifs that have evolved and that might act as determinants of SL-KAR signalling specificity. These specificities resulted from functional diversities among the clades. Our results suggest that a gradual co-evolution of SMXL members with their upstream receptors D14/KAI2 provided an increased specificity to both the SL perception and response in land plants.
- MeSH
- Arabidopsis genetika metabolismus MeSH
- laktony metabolismus MeSH
- molekulární evoluce * MeSH
- multigenová rodina * MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulátory růstu rostlin metabolismus MeSH
- signální transdukce MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Quorum sensing is a widespread form of cell-to-cell communication, which is based on the production of signaling molecules known as autoinducers (AIs). The first group contains highly species-specific N-acyl homoserine lactones (N-AHLs), generally known as AI-1, which are produced by AHL synthase. The second group, possessing the characteristic structure of a furanone ring, are known as AI-2. The enzyme responsible for their production is S-ribosylhomocysteine lyase (LuxS). In Campylobacter jejuni, AI-2 and LuxS play a role in many important processes, including biofilm formation, stress response, motility, expression of virulence factors, and colonization. However, neither the receptor protein nor the exact structure of the AI-2 molecule have been identified to date. Similarly, little is known about the possible existence of AHL-synthase producing AI-1 and its impact on gene expression. Recently, an analogue of homoserine lactone, called cjA, was isolated from a cell-free supernatant of C. jejuni strain 81-176 and from the food isolate c11. The molecule cjA particularly impacted the expression of virulence factors and biofilm formation. This review summarizes the role of AI-2 and cjA in the context of biofilm formation, motility, stress responses, and expression of virulence factors.
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- biofilmy růst a vývoj MeSH
- Campylobacter jejuni genetika metabolismus patogenita MeSH
- druhová specificita MeSH
- faktory virulence metabolismus MeSH
- fyziologický stres fyziologie MeSH
- gama-butyrolakton analogy a deriváty genetika metabolismus MeSH
- homoserin analogy a deriváty genetika metabolismus MeSH
- laktony metabolismus MeSH
- quorum sensing MeSH
- regulace genové exprese u bakterií * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Strigolactones (SL) contribute to drought acclimatization in shoots, because SL-depleted plants are hypersensitive to drought due to stomatal hyposensitivity to abscisic acid (ABA). However, under drought, SL biosynthesis is repressed in roots, suggesting organ specificity in their metabolism and role. Because SL can be transported acropetally, such a drop may also affect shoots, as a systemic indication of stress. We investigated this hypothesis by analysing molecularly and physiologically wild-type (WT) tomato (Solanum lycopersicum) scions grafted onto SL-depleted rootstocks, compared with self-grafted WT and SL-depleted genotypes, during a drought time-course. Shoots receiving few SL from the roots behaved as if under mild stress even if irrigated. Their stomata were hypersensitive to ABA (likely via a localized enhancement of SL synthesis in shoots). Exogenous SL also enhanced stomata sensitivity to ABA. As the partial shift of SL synthesis from roots to shoots mimics what happens under drought, a reduction of root-produced SL might represent a systemic signal unlinked from shootward ABA translocation, and sufficient to prime the plant for better stress avoidance.
- MeSH
- biologické modely MeSH
- biosyntetické dráhy genetika MeSH
- dehydratace MeSH
- fenotyp MeSH
- fyziologický stres * genetika MeSH
- kořeny rostlin metabolismus MeSH
- kyselina abscisová metabolismus MeSH
- laktony metabolismus MeSH
- listy rostlin fyziologie MeSH
- messenger RNA genetika metabolismus MeSH
- období sucha * MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné geny MeSH
- signální transdukce * MeSH
- Solanum lycopersicum genetika fyziologie MeSH
- transpirace rostlin MeSH
- voda fyziologie MeSH
- výhonky rostlin genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
MAIN CONCLUSION: The key step in the mode of action of strigolactones is the enzymatic detachment of the D-ring. The thus formed hydroxy butenolide induces conformational changes of the receptor pocket which trigger a cascade of reactions in the signal transduction. Strigolactones (SLs) constitute a new class of plant hormones which are of increasing importance in plant science. For the last 60 years, they have been known as germination stimulants for parasitic plants. Recently, several new bio-properties of SLs have been discovered such as the branching factor for arbuscular mycorrhizal fungi, regulation of plant architecture (inhibition of bud outgrowth and of shoot branching) and the response to abiotic factors, etc. To broaden horizons and encourage new ideas for identifying and synthesising new and structurally simple SLs, this review is focused on molecular aspects of this new class of plant hormones. Special attention has been given to structural features, the mode of action of these phytohormones in various biological actions, the design of SL analogs and their applications.
Ultrahigh-performance liquid chromatography coupled with high-mass-accuracy tandem mass spectrometry (UHPLC-MS-MS) has been used for elucidation of the structures of oxidation products of atorvastatin (AT), one of the most popular commercially available drugs. The purpose of the study was identification of AT metabolites in rat hepatocytes and comparison with electrochemically generated oxidation products. AT was incubated with rat hepatocytes for 24 h. Electrochemical oxidation of AT was performed by use of a three-electrode off-line system with a glassy carbon working electrode. Three supporting electrolytes (0.1 mol L(-1) H2SO4, 0.1 mol L(-1) HCl, and 0.1 mol L(-1) NaCl) were tested, and dependence on pH was also investigated. AT undergoes oxidation by a single irreversible process at approximately +1.0 V vs. Ag/AgCl electrode. The results obtained revealed a simple and relatively fast way of determining the type of oxidation and its position, on the basis of characteristic neutral losses (NLs) and fragment ions. Unfortunately, different products were obtained by electrochemical oxidation and biotransformation of AT. High-mass-accuracy measurement combined with different UHPLC-MS-MS scans, for example reconstructed ion-current chromatograms, constant neutral loss chromatograms, or exact mass filtering, enable rapid identification of drug-related compounds. β-Oxidation, aromatic hydroxylation of the phenylaminocarbonyl group, sulfation, AT lactone and glycol formation were observed in rat biotransformation samples. In contrast, a variety of oxidation reactions on the conjugated skeleton of isopropyl substituent of AT were identified as products of electrolysis.
- MeSH
- biologický transport MeSH
- biotransformace MeSH
- elektrolýza MeSH
- glykoly chemie metabolismus MeSH
- hepatocyty cytologie účinky léků metabolismus MeSH
- hydroxylace MeSH
- koncentrace vodíkových iontů MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- kyseliny heptylové chemie metabolismus MeSH
- laktony chemie metabolismus MeSH
- molekulová hmotnost MeSH
- oxidace-redukce MeSH
- pyrroly chemie metabolismus MeSH
- tandemová hmotnostní spektrometrie MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Pseudomonas chlororaphis strain 449 isolated from the rhizosphere of maize suppresses numerous plant pathogens in vitro. The strain produces phenazine antibiotics and synthesizes at least three types of quorum sensing signaling molecules, N-acylhomoserine lactones. Here we have shown that the rhizospheric P. chlororaphis strains 449, well known strain 30-84 as well as two other P. chlororaphis strains exhibit polygalacturonase activity. Using mini-Tn5 transposon mutagenesis, four independent mutants of strain P. chlororaphis 449 with insertion of mini-Tn5 Km2 in gene gacS of two-component GacA-GacS system of global regulation were selected. All these mutant strains were deficient in production of extracellular proteinase(s), phenazines, N-acylhomoserine lactones synthesis, and did not inhibit the growth of G(+) bacteria in comparison with the wild type strain. The P. chlororaphis 449-06 gacS (-) mutant studied in greater detail was deficient in polygalacturonase, pectin methylesterase activities, swarming motility and antifungal activity. It is the first time the involvement of GacA-GacS system in the regulation of enzymes of pectin metabolism, polygalacturonase and pectin methylesterase, was demonstrated in fluorescent pseudomonads.
- MeSH
- antibióza MeSH
- bakteriální proteiny genetika metabolismus MeSH
- houby fyziologie MeSH
- karboxylesterhydrolasy genetika metabolismus MeSH
- laktony metabolismus MeSH
- mutace MeSH
- polygalakturonasa genetika metabolismus MeSH
- Pseudomonas enzymologie fyziologie genetika MeSH
- půdní mikrobiologie MeSH
- regulace genové exprese u bakterií MeSH
- transkripční faktory genetika metabolismus MeSH
- vývojová regulace genové exprese MeSH
