Surfactin, an anionic lipopeptide produced by Bacillus subtilis, is an antimicrobial that targets the cytoplasmic membrane. Nowadays it appears increasingly apparent that the mechanism of resistance against these types of antibiotics consists of target site modification. This prompted us to investigate whether the surfactin non-producing strain B. subtilis 168 changes its membrane composition in response to a sublethal surfactin concentration. Here we show that the exposure of B. subtilis to surfactin at concentrations of 350 and 650 μg/ml (designated as SF350 and SF650, respectively) leads to a concentration-dependent growth arrest followed by regrowth with an altered growth rate. Analysis of the membrane lipid composition revealed modifications both in the polar head group and the fatty acid region. The presence of either surfactin concentration resulted in a reduction in the content of the major membrane phospholipid phosphatidylglycerol (PG) and increase in phosphatidylethanolamine (PE), which was accompanied by elevated levels of phosphatidic acid (PA) in SF350 cultures. The fatty acid analysis of SF350 cells showed a marked increase in non-branched high-melting fatty acids, which lowered the fluidity of the membrane interior measured as the steady-state fluorescence anisotropy of DPH. The liposome leakage of carboxyfluorescein-loaded vesicles resembling the phospholipid composition of surfactin-adapted cells showed that the susceptibility to surfactin-induced leakage is strongly reduced when the PG/PE ratio decreases and/or PA is included in the target bilayer. We concluded that the modifications of the phospholipid content of B. subtilis cells might provide a self-tolerance of the membrane active surfactin.

• Klíčová slova
• Bacillus subtilis, membrane, phospholipids, surfactin,
• MeSH
• Bacillus subtilis chemie   účinky léků   růst a vývoj   MeSH
• cyklické peptidy farmakologie   MeSH
• fluidita membrány účinky léků   MeSH
• fosfolipidy analýza   MeSH
• lipopeptidy farmakologie   MeSH
• mastné kyseliny analýza   MeSH
• membránové lipidy analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cyklické peptidy MeSH
• fosfolipidy MeSH
• lipopeptidy MeSH
• mastné kyseliny MeSH
• membránové lipidy MeSH
• surfactin peptide MeSH Prohlížeč

Plants harvest photons for photosynthesis using light-harvesting complexes (LHCs)-an array of chlorophyll proteins that can reversibly switch from harvesting to energy-dissipation mode to prevent over-excitation and damage of the photosynthetic apparatus. In unicellular algae and lower plants this process requires the LHCSR proteins which senses over-acidification of the lumen trough protonatable residues exposed to the thylakoid lumen to activate quenching reactions. Further activation is provided by replacement of the violaxanthin ligand with its de-epoxidized product, zeaxanthin, also induced by excess light. We have produced the ppLHCSR1 protein from Physcomitrella patens by over-expression in tobacco and purified it in either its violaxanthin- or the zeaxanthin-binding form with the aim of analyzing their spectroscopic properties at either neutral or acidic pH. Using femtosecond spectroscopy, we demonstrated that the energy dissipation is achieved by two distinct quenching mechanism which are both activated by low pH. The first is present in both ppLHCSR1-Vio and ppLHCSR1-Zea and is characterized by 30-40ps time constant. The spectrum of the quenching product is reminiscent of a carotenoid radical cation, suggesting that the pH-induced quenching mechanism is likely electron transfer from the carotenoid to the excited Chl a. In addition, a second quenching channel populating the S1 state of carotenoid via energy transfer from Chl is found exclusively in the ppLHCSR1-Zea at pH5. These results provide proof of principle that more than one quenching mechanism may operate in the LHC superfamily and also help understanding the photoprotective role of LHCSR proteins and the evolution of LHC antennae.

• Klíčová slova
• Carotenoids, Femtosecond spectroscopy, LHCSR, Non-photochemical quenching,
• MeSH
• biologické modely MeSH
• chlorofyl metabolismus   MeSH
• fotosyntéza * genetika   účinky záření   MeSH
• geneticky modifikované rostliny genetika   metabolismus   účinky záření   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• mechy genetika   metabolismus   účinky záření   MeSH
• přenos energie MeSH
• spektrální analýza MeSH
• světlosběrné proteinové komplexy genetika   metabolismus   účinky záření   MeSH
• tabák genetika   metabolismus   účinky záření   MeSH
• transport elektronů MeSH
• vazba proteinů MeSH
• xanthofyly metabolismus   MeSH
• zeaxanthiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorofyl MeSH
• světlosběrné proteinové komplexy MeSH
• violaxanthin MeSH Prohlížeč
• xanthofyly MeSH
• zeaxanthiny MeSH

DNMT1 is the maintenance DNA methyltransferase shown to be essential for embryonic development and cellular growth and differentiation in many somatic tissues in mammals. Increasing evidence has also suggested a role for DNMT1 in repressing gene expression through interactions with specific transcription factors. Previously, we identified DNMT1 as an interacting partner of the TR2/TR4 nuclear receptor heterodimer in erythroid cells, implicated in the developmental silencing of fetal β-type globin genes in the adult stage of human erythropoiesis. Here, we extended this work by using a biotinylation tagging approach to characterize DNMT1 protein complexes in mouse erythroleukemic cells. We identified novel DNMT1 interactions with several hematopoietic transcription factors with essential roles in erythroid differentiation, including GATA1, GFI-1b and FOG-1. We provide evidence for DNMT1 forming distinct protein subcomplexes with specific transcription factors and propose the existence of a "core" DNMT1 complex with the transcription factors ZBP-89 and ZNF143, which is also present in non-hematopoietic cells. Furthermore, we identified the short (17a.a.) PCNA Binding Domain (PBD) located near the N-terminus of DNMT1 as being necessary for mediating interactions with the transcription factors described herein. Lastly, we provide evidence for DNMT1 serving as a co-repressor of ZBP-89 and GATA1 acting through upstream regulatory elements of the PU.1 and GATA1 gene loci.

• Klíčová slova
• DNMT1, Epigenetics, Erythropoiesis, Transcription factors,
• MeSH
• buněčná diferenciace genetika   MeSH
• DNA vazebné proteiny genetika   metabolismus   MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   metabolismus   MeSH
• DNA-(cytosin-5)-methyltransferasa 1 MeSH
• erytroidní buňky chemie   metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• metylace DNA genetika   MeSH
• multiproteinové komplexy genetika   metabolismus   MeSH
• myši MeSH
• protoonkogenní proteiny genetika   metabolismus   MeSH
• regulace genové exprese genetika   MeSH
• represorové proteiny genetika   metabolismus   MeSH
• trans-aktivátory genetika   metabolismus   MeSH
• transkripční faktor GATA1 genetika   metabolismus   MeSH
• transkripční faktory genetika   metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• DNA-(cytosin-5-)methyltransferasa MeSH
• DNA-(cytosin-5)-methyltransferasa 1 MeSH
• DNMT1 protein, human MeSH Prohlížeč
• Dnmt1 protein, mouse MeSH Prohlížeč
• Gata1 protein, mouse MeSH Prohlížeč
• Gfi1b protein, mouse MeSH Prohlížeč
• jaderné proteiny MeSH
• multiproteinové komplexy MeSH
• proto-oncogene protein Spi-1 MeSH Prohlížeč
• protoonkogenní proteiny MeSH
• represorové proteiny MeSH
• trans-aktivátory MeSH
• transkripční faktor GATA1 MeSH
• transkripční faktory MeSH
• Zfp148 protein, mouse MeSH Prohlížeč
• Zfpm1 protein, mouse MeSH Prohlížeč

Aggregation induced conformational change of light harvesting antenna complexes is believed to constitute one of the pathways through which photosynthetic organisms can safely dissipate the surplus of energy while exposed to saturating light. In this study, Stark fluorescence (SF) spectroscopy is applied to minor antenna complexes (CP24, CP26 and CP29) both in their light-harvesting and energy-dissipating states to trace and characterize different species generated upon energy dissipation through aggregation (in-vitro) induced conformational change. SF spectroscopy could identify three spectral species in the dissipative state of CP24, two in CP26 and only one in CP29. The comprehensive analysis of the SF spectra yielded different sets of molecular parameters for the multiple spectral species identified in CP24 or CP26, indicating the involvement of different pigments in their formation. Interestingly, a species giving emission around the 730nm spectral region is found to form in both CP24 and CP26 following transition to the energy dissipative state, but not in CP29. The SF analyses revealed that the far red species has exceptionally large charge transfer (CT) character in the excited state. Moreover, the far red species was found to be formed invariably in both Zeaxanthin (Z)- and Violaxathin (V)-enriched CP24 and CP26 antennas with identical CT character but with larger emission yield in Z-enriched ones. This suggests that the carotenoid Z is not directly involved but only confers an allosteric effect on the formation of the far red species. Similar far red species with remarkably large CT character were also observed in the dissipative state of the major light harvesting antenna (LHCII) of plants [Wahadoszamen et al. PCCP, 2012], the fucoxanthin-chlorophyll protein (FCP) of brown algae [Wahadoszamen et al. BBA, 2014] and cyanobacterial IsiA [Wahadoszamen et al. BBA, 2015], thus pointing to identical sites and pigments active in the formation of the far red quenching species in different organisms.

• Klíčová slova
• Charge transfer states, Light harvesting, Minor antenna complexes, Nonphotochemical quenching (NPQ), Photoprotective energy dissipation, Stark spectroscopy,
• MeSH
• chlorofyl metabolismus   účinky záření   MeSH
• druhová specificita MeSH
• fluorescenční spektrometrie MeSH
• fotosyntéza * účinky záření   MeSH
• konformace proteinů MeSH
• přenos energie MeSH
• Spinacia oleracea chemie   metabolismus   účinky záření   MeSH
• světlo MeSH
• světlosběrné proteinové komplexy chemie   metabolismus   účinky záření   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• xanthofyly metabolismus   MeSH
• zeaxanthiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorofyl MeSH
• světlosběrné proteinové komplexy MeSH
• violaxanthin MeSH Prohlížeč
• xanthofyly MeSH
• zeaxanthiny MeSH

Nonsense mediated RNA decay (NMD) is well-known as an RNA quality control mechanism that sequesters a substantial portion of RNA from expression by targeting it for degradation. However, a number of recent studies across a range of organisms indicate a broader role for NMD in gene regulation and transcriptome homeostasis. Here we propose a novel role for NMD as a buffering system with the capability of accumulating and subsequently releasing a wide spectrum of cryptic genetic variation in response to environmental stimuli, and hence facilitating adaptive evolution. We discuss this role for NMD in the context of evolution of plant pathogen defense, whereby NMD may promote rapid diversification of intracellular immune receptors by mitigating the potentially harmful impact of their newly formed variants on plant fitness.

• Klíčová slova
• Cryptic genetic variation, Evolvability, Gene duplication, NB-LRR immune receptors, Plant defense,
• MeSH
• messenger RNA biosyntéza   genetika   MeSH
• nesmyslný kodon MeSH
• nonsense mediated mRNA decay genetika   MeSH
• regulace genové exprese genetika   MeSH
• RNA biosyntéza   genetika   MeSH
• transkriptom genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• messenger RNA MeSH
• nesmyslný kodon MeSH
• RNA MeSH

To elucidate the consequences of the saturated-unsaturated nature of lipid surface films, monolayers formed by an equimolar mixture of 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipids are investigated in a wide range of surface pressures. As such mixtures share some features with naturally-occurring surfactants, for example the lung surfactant, the systems are studied at the temperature relevant for human body. All-atom molecular dynamics simulations and Langmuir trough experiments are employed. The binary lipid mixture is compared with the corresponding one-component systems. Atomistic-level alterations of monolayer molecular properties upon lateral compression are scrutinized. These involve elevation of lateral ordering of lipid chains, modulation of chain and headgroup orientation, and reduction of lipid hydration. The presence of the unsaturated POPC in the DPPC/POPC mixture reduces the liquid expanded-liquid condensed coexistence region and moderates the phase transition. Simulations predict that nanoscale lipid de-mixing occurs with small transient DPPC clusters emerging due to local fluctuations of the lateral lipid arrangement. A vertical sorting of lipids induced by lateral compression is also observed, with DPPC transferred toward the water phase. Both the conformational lipid alterations due to monolayer compression as well as the existence of lateral dynamic inhomogeneities of the lipid film are potentially pertain to dynamic and non-homogeneous lipid interfacial systems.

• Klíčová slova
• Langmuir trough, Lung surfactant, Molecular dynamics, Phospholipid monolayers,
• MeSH
• 1,2-dipalmitoylfosfatidylcholin analogy a deriváty   chemie   MeSH
• fosfatidylcholiny chemie   MeSH
• lipidy chemie   MeSH
• molekulární konformace MeSH
• simulace molekulární dynamiky * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,2-dipalmitoyl-sn-glycero-3-ethylphosphocholine MeSH Prohlížeč
• 1,2-dipalmitoylfosfatidylcholin MeSH
• 1,2-oleoylphosphatidylcholine MeSH Prohlížeč
• fosfatidylcholiny MeSH
• lipidy MeSH

BACKGROUND: Inflammatory-mediated pathological processes in the endothelium arise as a consequence of the dysregulation of vascular homeostasis. Of particular importance are mediators produced by stimulated monocytes/macrophages inducing activation of endothelial cells (ECs). This is manifested by excessive soluble pro-inflammatory mediator production and cell surface adhesion molecule expression. Nitro-fatty acids are endogenous products of metabolic and inflammatory reactions that display immuno-regulatory potential and may represent a novel therapeutic strategy to treat inflammatory diseases. The purpose of our study was to characterize the effects of nitro-oleic acid (OA-NO2) on inflammatory responses and the endothelial-mesenchymal transition (EndMT) in ECs that is a consequence of the altered healing phase of the immune response. METHODS: The effect of OA-NO2 on inflammatory responses and EndMT was determined in murine macrophages and murine and human ECs using Western blotting, ELISA, immunostaining, and functional assays. RESULTS: OA-NO2 limited the activation of macrophages and ECs by reducing pro-inflammatory cytokine production and adhesion molecule expression through its modulation of STAT, MAPK and NF-κB-regulated signaling. OA-NO2 also decreased transforming growth factor-β-stimulated EndMT and pro-fibrotic phenotype of ECs. These effects are related to the downregulation of Smad2/3. CONCLUSIONS: The study shows the pleiotropic effect of OA-NO2 on regulating EC-macrophage interactions during the immune response and suggests a role for OA-NO2 in the regulation of vascular endothelial immune and fibrotic responses arising during chronic inflammation. GENERAL SIGNIFICANCE: These findings propose the OA-NO2 may be useful as a novel therapeutic agent for treatment of cardiovascular disorders associated with dysregulation of the endothelial immune response.

• Klíčová slova
• Endothelial cells, Endothelial-mesenchymal transition, Macrophages, Nitro-fatty acids, Nitro-oleic acid, Vascular inflammation,
• MeSH
• cévní endotel cytologie   účinky léků   metabolismus   MeSH
• endoteliální buňky účinky léků   metabolismus   MeSH
• epitelo-mezenchymální tranzice * MeSH
• kyseliny olejové farmakologie   MeSH
• lidé MeSH
• makrofágy účinky léků   metabolismus   MeSH
• MAP kinasový signální systém MeSH
• myši MeSH
• NF-kappa B metabolismus   MeSH
• proteiny Smad metabolismus   MeSH
• transformující růstový faktor beta farmakologie   MeSH
• transkripční faktory STAT metabolismus   MeSH
• zánět metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• 10-nitro-oleic acid MeSH Prohlížeč
• kyseliny olejové MeSH
• NF-kappa B MeSH
• proteiny Smad MeSH
• transformující růstový faktor beta MeSH
• transkripční faktory STAT MeSH

When exposed to constant low temperatures (CLTs), insects often suffer from cumulative physiological injuries that can severely compromise their fitness and survival. Yet, mortality can be considerably lowered when the cold stress period is interrupted by periodic warm interruption(s), referred to as fluctuating thermal regimes, FTRs. In this study, we have shown that FTRs strongly promoted cold tolerance of Drosophila melanogaster adults. We then assessed whether this marked phenotypic shift was associated with detectable physiological changes, such as synthesis of cryoprotectants and/or membrane remodeling. To test these hypotheses, we conducted two different time-series Omics analyzes in adult flies submitted to CLTs vs. FTRs: metabolomics (GC/MS) and lipidomics (LC/ESI/MS) targeting membrane phospholipids. We observed increasing levels in several polyhydric alcohols (arabitol, erythritol, sorbitol, mannitol, glycerol), sugars (fructose, mannose) and amino acids (serine, alanine, glutamine) in flies under CLT. Prolonged exposure to low temperature was also associated with a marked deviation of metabolic homeostasis and warm interruptions as short as 2h were sufficient to periodically return the metabolic system to functionality. Lipidomics revealed an increased relative proportion of phosphatidylethanolamines and a shortening of fatty acyl chains in flies exposed to cold, likely to compensate for the ordering effect of low temperature on membranes. We found a remarkable correspondence in the time-course of changes between the metabolic and phospholipids networks, both suggesting a fast homeostatic regeneration during warm intervals under FTRs. In consequence, we suggest that periodic opportunities to restore system-wide homeostasis contribute to promote cold tolerance under FTRs.

• Klíčová slova
• Cold stress, Drosophila, Omics, fluctuating thermal regimes, recovery,
• MeSH
• analýza hlavních komponent MeSH
• Drosophila melanogaster metabolismus   MeSH
• fosfolipidy metabolismus   MeSH
• fyziologická adaptace * MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• lineární modely MeSH
• metabolismus lipidů * MeSH
• metabolomika metody   MeSH
• nízká teplota * MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• pravděpodobnost MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfolipidy MeSH

Resonance Raman spectroscopy was used to evaluate pigment structure in the FCP-like light-harvesting complex of Chromera velia (Chromera light-harvesting complex or CLH). This antenna protein contains chlorophyll a, violaxanthin and a new isofucoxanthin-like carotenoid (called Ifx-l). We show that Ifx-l is present in two non-equivalent binding pockets with different conformations, having their (0,0) absorption maxima at 515 and 548nm respectively. In this complex, only one violaxanthin population absorbing at 486nm is observed. All the CLH-bound carotenoid molecules are in all-trans configuration, and among the two Ifx-l carotenoid molecules, the red one is twisted, as is the red-absorbing lutein in LHCII trimers. Analysis of the carbonyl stretching region for Chl a excitations indicates CLH binds up to seven Chl a molecules in five non-equivalent binding sites, in reasonable agreement with sequence analyses which have identified eight potential coordinating residues. The binding modes and conformations of CLH-bound pigments are discussed with respect to the known structures of LHCII and FCP.

• Klíčová slova
• CLH, Carotenoids, Chlorophylls, Light harvesting complexes, Photosynthesis, Resonance Raman,
• MeSH
• Alveolata chemie   metabolismus   MeSH
• světlosběrné proteinové komplexy chemie   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• xanthofyly chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• isofucoxanthin MeSH Prohlížeč
• světlosběrné proteinové komplexy MeSH
• violaxanthin MeSH Prohlížeč
• xanthofyly MeSH

Analysis of polar lipids from eight psychrophilic yeasts (Cryptococcus victoriae, Cystofilobasidium capitatum, Holtermaniella wattica, Mrakiella aquatica, M. cryoconiti, Rhodotorula lignophila, Kondoa malvinella and Trichosporon aggtelekiense) grown at 4-28°C by hydrophilic interaction liquid chromatography/high resolution electrospray ionization tandem mass spectrometry determined 17 classes of lipids and identified dozens of molecular species of phospholipids including their regioisomers. Most of the yeasts were able to grow over the whole temperature range, reaching the highest biomass at 4 or 10°C. On temperature drop to 4°C, all eight strains showed a significant decrease of MUFA and a simultaneous increase of PUFA such as α-linolenic acid, the content of which in the biomass reached up to 20%. We also found alterations in the proportions of individual phospholipids (PI, PE and PC), the PC/PE-ratio decreasing with decreasing temperature. With increasing temperature the content of PoO-PC rose while that of LL-PC decreased, the drop in the content of LL-PC being nearly 100-fold while the content of PoO-PC increased more than twice. A change in temperature brought about changes in molecular species of PC (molecular species PO-PC versus OP-PC) as well as PE, i.e. PO-PE and OP-PE. The phase transition temperature of PO-PC differs from OP-PC by 7°C and the difference between PO-PE and OP-PE is some 10°C; we thus assume that the cell compensates for the adverse temperature effect by changing the fatty acids in the sn-1 and sn-2 positions.

• Klíčová slova
• Lipidomic analysis, Phosphatidylcholine, Phosphatidylethanolamine, Phospholipids, Psychrophilic yeast, Regioisomers,
• MeSH
• analýza hlavních komponent MeSH
• fosfolipidy chemie   metabolismus   MeSH
• kvasinky růst a vývoj   metabolismus   MeSH
• mastné kyseliny biosyntéza   chemie   MeSH
• metabolismus lipidů * MeSH
• metabolomika metody   MeSH
• teplota * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfolipidy MeSH
• mastné kyseliny MeSH