Brachypodium distachyon is a useful model organism for studying interaction of cereals with phytopathogenic fungi. The present study tested the possibility of a compatible interaction of B. distachyon with the endophytic fungus Microdochium bolleyi originated from wheat roots. There was evaluated the effect of this endophytic fungus on the intensity of the attack by pathogen Fusarium culmorum in B. distachyon and wheat, and also changes in expression of genes (in B. distachyon: BdChitinase1, BdPR1-5, BdLOX3, BdPAL, BdEIN3, and BdAOS; and in wheat: TaB2H2(chitinase), TaPR1.1, TaLOX, TaPAL, TaEIN2, and TaAOS) involved in defence against pathogens. Using light microscopy and newly developed specific primers was found to be root colonization of B. distachyon by the endophyte M. bolleyi. B. distachyon plants, as well as wheat inoculated with M. bolleyi showed significantly weaker symptoms on leaves from infection by fungus F. culmorum than did plants without the endophyte. Expression of genes BdPR1-5, BdChitinase1, and BdLOX3 in B. distachyon and of TaPR1.1 and TaB2H2 in wheat was upregulated after infection with F. culmorum. M. bolleyi-mediated resistance in B. distachyon was independent of the expression of the most tested genes. Taken together, the results of the present study show that B. distachyon can be used as a model host system for endophytic fungus M. bolleyi.

• MeSH
• Ascomycota * genetika   MeSH
• Brachypodium * genetika   mikrobiologie   MeSH
• interakce hostitele a patogenu MeSH
• nemoci rostlin mikrobiologie   MeSH
• pšenice genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Phytohormone levels and the expression of genes encoding key enzymes participating in hormone biosynthetic pathways were investigated in pepper leaves inoculated with two different tobamoviruses. Obuda pepper virus (ObPV) inoculation led to the development of hypersensitive reaction (incompatible interaction), while Pepper mild mottle virus (PMMoV) inoculation resulted in a systemic, compatible interaction. ObPV-inoculation markedly increased not only the levels of salicylic acid (SA) (73-fold) and jasmonic acid (8-fold) but also those of abscisic acid, indole-3-acetic acid, indole-3-butyric acid, cis-zeatin, cis-zeatin-9-riboside and trans-zeatin-9-riboside in the inoculated pepper leaves 3 days post inoculation. PMMoV infection increased only the contents of gibberellic acid and SA. Hormone contents did not change significantly after ObPV or PMMoV infection in non-infected upper leaves 20 days post inoculation. Concentrations of some brassinosteroids (BRs) and progesterone increased both in ObPV- and PMMoV inoculated leaves. ObPV inoculation markedly induced the expression of three phenylalanine ammonia-lyase (PAL) and a 1-aminocyclopropane-1-carboxylate oxidase (ACO) genes, while that of an isochorismate synthase (ICS) gene was not modified. PMMoV inoculation did not alter the expression of PAL and ICS genes but induced the transcript abundance of ACO although later than ObPV. Pre-treatment of pepper leaves with exogenous 24-epi-brassinolide (24-epi-BR) prior to ObPV-inoculation strongly mitigated the visible symptoms caused by ObPV. In addition, 24-epi-BR pre-treatment markedly altered the level of several hormones in pepper leaves following ObPV-inoculation. These data indicate that ObPV- and PMMoV-inoculations lead to intricate but well harmonized hormonal responses that are largely determined by the incompatible or compatible nature of plant-virus interactions.

• Klíčová slova
• Brassinosteroids, Ethylene, Hormone, Pepper, Phenylalanine ammonia lyase, Progesterone, Salicylic acid, Tobamovirus,
• MeSH
• Capsicum genetika   metabolismus   virologie   MeSH
• druhová specificita MeSH
• fenylalaninamoniaklyasa genetika   metabolismus   MeSH
• interakce hostitele a patogenu genetika   fyziologie   MeSH
• intramolekulární transferasy genetika   metabolismus   MeSH
• listy rostlin metabolismus   MeSH
• nemoci rostlin virologie   MeSH
• oxidoreduktasy aminokyselin genetika   metabolismus   MeSH
• progesteron metabolismus   MeSH
• regulace genové exprese enzymů MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin metabolismus   MeSH
• rostlinné geny MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• signální transdukce MeSH
• Tobamovirus klasifikace   patogenita   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 1-aminocyclopropane-1-carboxylic acid oxidase MeSH Prohlížeč
• fenylalaninamoniaklyasa MeSH
• intramolekulární transferasy MeSH
• isochorismate synthase MeSH Prohlížeč
• oxidoreduktasy aminokyselin MeSH
• progesteron MeSH
• regulátory růstu rostlin MeSH
• rostlinné proteiny MeSH

Schistosome cercariae are able to penetrate into the skin of various vertebrate hosts. However, in contrast to the compatible host, the infection of incompatible hosts results in the death of parasites at various intervals post-infection. In order to compare the immune responses in both types of host infected with Trichobilharzia regenti, Trichobilharzia szidatior Schistosoma mansoni, antibody responses against various T. regenti, T. szidatiand S. mansonischistosome developmental stages were studied. Indirect immunofluorescence tests (IFAT) demonstrated no species-specific reactivity of human, mouse or duck immune sera with cercarial surfaces. Study of the cercarial glands also gave no significant results. However, differences were found in schistosomular and adult antigens: only the sera of compatible hosts recognised schistosomular and adult gut associated antigens in homologous as well as heterologous systems. Based on the presented data, our study supports the use of IFAT for the serological differentiation of schistosomiasis and cercarial dermatitis caused by bird schistosomes.

• MeSH
• antigeny helmintové imunologie   MeSH
• fluorescenční protilátková technika * MeSH
• interakce hostitele a parazita MeSH
• kachny MeSH
• myši bezsrsté MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• ovum imunologie   ultrastruktura   MeSH
• protilátky helmintové imunologie   MeSH
• Schistosoma mansoni růst a vývoj   imunologie   metabolismus   MeSH
• Schistosomatidae růst a vývoj   imunologie   metabolismus   MeSH
• stadia vývoje MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny helmintové MeSH
• protilátky helmintové MeSH

Charge scaling has proven to be an efficient way to account in a mean-field manner for electronic polarization by aqueous ions in force field molecular dynamics simulations. However, commonly used water models with dielectric constants over 50 are not consistent with this approach leading to "overscaling", i.e., generally too weak ion-ion interactions. Here, we build water models fully compatible with charge scaling, i.e., having the correct low-frequency dielectric constant of about 45. To this end, we employ advanced optimization and machine learning schemes in order to explore the vast parameter space of four-site water models efficiently. As an a priori unwarranted positive result, we find a sizable range of force field parameters that satisfy the above dielectric constant constraint providing at the same time accuracy with respect to experimental data comparable with the best existing four-site water models such as TIP4P/2005, TIP4P-FB, or OPC. The present results thus open the way to the development of a consistent charge scaling force field for modeling ions in aqueous solutions.

• Publikační typ
• časopisecké články MeSH

We present a technology that allows the preparation of matrix-assisted laser desorption/ionization (MALDI)-compatible protein chips by ambient ion landing of proteins and successive utilization of the resulting protein chips for the development of bioanalytical assays. These assays are based on the interaction between the immobilized protein and the sampled analyte directly on the protein chip and subsequent in situ analysis by MALDI mass spectrometry. The electrosprayed proteins are immobilized on dry metal and metal oxide surfaces, which are nonreactive under normal conditions. The ion landing of electrosprayed protein molecules is performed under atmospheric pressure by an automated ion landing apparatus that can manufacture protein chips with a predefined array of sample positions or any other geometry of choice. The protein chips prepared by this technique are fully compatible with MALDI ionization because the metal-based substrates are conductive and durable enough to be used directly as MALDI plates. Compared to other materials, the nonreactive surfaces show minimal nonspecific interactions with chemical species in the investigated sample and are thus an ideal substrate for selective protein chips. Three types of protein chips were used in this report to demonstrate the bioanalytical applications of ambient ion landing. The protein chips with immobilized proteolytic enzymes showed the usefulness for fast in situ peptide MALDI sequencing; the lectin-based protein chips showed the ability to enrich glycopeptides from complex mixtures with subsequent MALDI analysis, and the protein chips with immobilized antibodies were used for a novel immunoMALDI workflow that allowed the enrichment of antigens from the serum followed by highly specific MALDI detection.

• MeSH
• čipová analýza proteinů * MeSH
• ionty chemie   MeSH
• povrchové vlastnosti MeSH
• proteiny analýza   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ionty MeSH
• proteiny MeSH

The goal of this work is a systematic optimization of hydrophilic interaction liquid chromatography (HILIC) separation of acidic lipid classes (namely phosphatidic acids-PA, lysophosphatidic acids-LPA, phosphatidylserines-PS and lysophosphatidylserines-LPS) and other lipid classes under mass spectrometry (MS) compatible conditions. The main parameters included in this optimization are the type of stationary phases used in HILIC, pH of the mobile phase, the type and concentration of mobile phase additives. Nine HILIC columns with different chemistries (unmodified silica, modified silica using diol, 2-picolylamine, diethylamine and 1-aminoanthracene and hydride silica) are compared with the emphasis on peak shapes of acidic lipid classes. The optimization of pH is correlated with the theoretical calculation of acidobasic equilibria of studied lipid classes. The final method using the hydride column, pH 4 adjusted by formic acid and the gradient of acetonitrile and 40 mmol/L of aqueous ammonium formate provides good peak shapes for all analyzed lipid classes including acidic lipids. This method is applied for the identification of lipids in real samples of porcine brain and kidney extracts.

• Klíčová slova
• HILIC, LC/MS, Lysophospholipids, Phosphatidic acid, Phosphatidylserine, Phospholipids,
• MeSH
• chromatografie kapalinová metody   MeSH
• fosfatidylseriny analýza   MeSH
• hmotnostní spektrometrie metody   MeSH
• hydrofobní a hydrofilní interakce MeSH
• koncentrace vodíkových iontů MeSH
• ledviny chemie   MeSH
• lipidy analýza   MeSH
• lysofosfolipidy analýza   MeSH
• mozek - chemie MeSH
• oxid křemičitý MeSH
• prasata MeSH
• stereoizomerie MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfatidylseriny MeSH
• lipidy MeSH
• lysofosfolipidy MeSH
• lysophosphatidylserine MeSH Prohlížeč
• oxid křemičitý MeSH

Clinical effectiveness of hyperthermia treatments, in which tumor tissue is artificially heated to 40-44 °C for 60-90 min, can be hampered by a lack of accurate temperature monitoring. The need for noninvasive temperature monitoring in the head and neck region (H&N) and the potential of MR thermometry prompt us to design an MR compatible hyperthermia applicator: the MRcollar. In this work, we validate the design, numerical model, and MR performance of the MRcollar. The MRcollar antennas have low reflection coefficients (<-15 dB) and the intended low interaction between the individual antenna modules (<-32 dB). A 10 °C increase in 3 min was reached in a muscle-equivalent phantom, such that the specifications from the European Society for Hyperthermic Oncology were easily reached. The MRcollar had a minimal effect on MR image quality and a five-fold improvement in SNR was achieved using the integrated coils of the MRcollar, compared to the body coil. The feasibility of using the MRcollar in an MR environment was shown by a synchronous heating experiment. The match between the predicted SAR and measured SAR using MR thermometry satisfied the gamma criteria [distance-to-agreement = 5 mm, dose-difference = 7%]. All experiments combined show that the MRcollar delivers on the needs for MR-hyperthermia in the H&N and is ready for in vivo investigation.

• Klíčová slova
• MR thermometry, MRI guided interventions, hyperthermia, microwave hyperthermia,
• Publikační typ
• časopisecké články MeSH

RNA G-quadruplexes have been suggested to play key roles in fundamental biological processes and are linked to human diseases. Thus, they also represent good potential therapeutic targets. Here, we describe, using the methods of molecular biophysics, interactions of a series of biologically-active supramolecular cationic metallohelices with human telomeric RNA G-quadruplex. We demonstrate that the investigated metallohelices bind with a high affinity to human telomeric RNA G-quadruplex and that their binding selectivity considerably differs depending on the dimensions and overall shape of the metallohelices. Additionally, the investigated metallohelices inhibit DNA synthesis on the RNA template containing four repeats of the human telomeric sequence by stabilizing the RNA G-quadruplex structure. Collectively, the results of this study suggest that stabilization of RNA sequences capable of G-quadruplex formation by metallohelices investigated in this work might contribute to the mechanism of their biological activity.

• MeSH
• DNA chemie   metabolismus   MeSH
• G-kvadruplexy * MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• RNA chemie   metabolismus   MeSH
• telomery metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• RNA MeSH

This paper presents a systematic study of the retention behavior of a model bisdioxopiperazine drug, dexrazoxane (DEX) and its three polar metabolites (two single open-ring intermediates-B and C and an EDTA-like active compound ADR-925) on different stationary phases intended for hydrophilic interaction liquid chromatography (HILIC). The main aim was to estimate advantages and limitations of HILIC in the simultaneous analysis of a moderately lipophilic parent drug and its highly polar metabolites, including positional isomers, under MS compatible conditions. The study involved two bare silica columns (Ascentic Express HILIC, Atlantis HILIC) and two stationary phases with distinct zwitterionic properties (Obelisc N and ZIC HILIC). The chromatographic conditions (mobile phase strength and pH, column temperature) were systematically modified to assess their impact on retention and separation of the studied compounds. It was found that the bare silica phases were unable to separate the positional isomers (intermediates B and C), whereas both columns with zwitterionic properties (Obelisc N and ZIC HILIC) were able to separate these structurally very similar compounds. However, only ZIC HILIC phase allowed appropriate separation of DEX and all its metabolites to a base line within a single run. A mobile phase composed of a mixture of ammonium formate (0.5 mM) and acetonitrile (25:75, v/v) was suggested as optimal for the simultaneous analysis of DEX and its metabolites on ZIC HILIC. Thereafter, HILIC-LC-MS analysis of DEX and all its metabolites was performed for the first time to obtain basic data about the applicability of the suggested chromatographic conditions. Hence, this study demonstrates that HILIC could be a viable solution for the challenging analysis of moderately polar parent drug along with its highly polar metabolites including the ability to separate structurally very similar compounds, such as positional isomers.

• MeSH
• chemické modely * MeSH
• chromatografie kapalinová metody   MeSH
• ethylendiaminy chemie   izolace a purifikace   MeSH
• glycin analogy a deriváty   chemie   izolace a purifikace   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kardiovaskulární látky chemie   izolace a purifikace   MeSH
• koncentrace vodíkových iontů MeSH
• razoxan chemie   izolace a purifikace   MeSH
• tandemová hmotnostní spektrometrie MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ethylendiaminy MeSH
• glycin MeSH
• ICRF 198 MeSH Prohlížeč
• kardiovaskulární látky MeSH
• razoxan MeSH

On isolated rat heart atria, atracurium competitively antagonized the negative chronotropic effect of methylfurmethide, shifting the concentration-response curve to the right without diminishing the agonist's maximal effect; Kd calculated from dose ratios was 3.0 mumol/l. On the longitudinal muscle of rat ileum, atracurium antagonized the effect of methylfurmethide in a non-competitive manner; at 50 mumol/l atracurium, the maximum response to methylfurmethide was diminished by about 50%. Atracurium antagonized the binding of (3H)quinuclidinyl benzilate [3H)QNB) to muscarinic binding sites in the atria, ileal longitudinal muscle and cerebellum with IC50 values of 5-8 mumol/l, and in brain cortex of 25 mumol/l. Atracurium was little efficient, however, in antagonizing the binding of N-(3H-methyl) scopolamine [3H)NMS) to muscarinic binding sites. Complete blockade was not achieved at concentrations up to 1 mmol/l. Concentrations required to diminish the binding by 50% were 10 - 1000 times higher for (3H)NMS than for (3H)QNB. Atracurium brought about the dissociation of (3H)QNB-receptor complexes, but its effect was considerably stronger at a concentration of 30 mumol/l than at 1 mmol/l. Atracurium slowed down the dissociation of (3H)QNB-receptor complexes observed after the addition of atropine. The effects of atracurium on the dissociation of (3H)NMS-receptor complexes were similar to those on (3H)QNB-receptor complexes, but a high concentration of atracurium (1 mmol/l) produced a transient increase in (3H)NMS binding preceding its subsequent dissociation. Although the observations of the antagonism by atracurium of the effect of methylfurmethide on the heart atria, and of the inhibition of the specific binding of (3H)QNB to the atria, ileal smooth muscle, cerebellum and brain cortex are compatible with the assumption of a competitive interaction, the discrepancy between the effects of atracurium on the binding of (3H)QNB and (3H)NMS indicates that atracurium does not bind to the same binding site as (3H)QNB and (3H)NMS. It appears that most effects of atracurium on muscarinic receptors are allosteric and that both negative and positive cooperatives play a role in interactions between atracurium and muscarinic ligands.

• MeSH
• atrakurium metabolismus   MeSH
• atropin farmakologie   MeSH
• chinuklidinylbenzilát metabolismus   MeSH
• hladké svalstvo metabolismus   ultrastruktura   MeSH
• inbrední kmeny potkanů MeSH
• krysa rodu Rattus MeSH
• lékové interakce MeSH
• mozková kůra metabolismus   ultrastruktura   MeSH
• muskarin analogy a deriváty   farmakologie   MeSH
• N-methylskopolamin MeSH
• parasympatolytika metabolismus   MeSH
• parasympatomimetika farmakologie   MeSH
• receptory cholinergní metabolismus   MeSH
• skopolaminové deriváty metabolismus   MeSH
• srdeční síně metabolismus   MeSH
• tritium MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 5-methylfurtrethonium MeSH Prohlížeč
• atrakurium MeSH
• atropin MeSH
• chinuklidinylbenzilát MeSH
• muskarin MeSH
• N-methylskopolamin MeSH
• parasympatolytika MeSH
• parasympatomimetika MeSH
• receptory cholinergní MeSH
• skopolaminové deriváty MeSH
• tritium MeSH