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1.
Plant J ; 115(1): 7-17, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36994646

RESUMO

The safe and smooth functioning of photosynthesis in plants is ensured by the operation of numerous regulatory mechanisms that adjust the density of excitation resulting from photon absorption to the capabilities of the photosynthetic apparatus. Such mechanisms include the movement of chloroplasts inside cells and the quenching of electronic excitations in the pigment-protein complexes. Here, we address the problem of a possible cause-and-effect relationship between these two mechanisms. Both the light-induced chloroplast movements and quenching of chlorophyll excitations were analyzed simultaneously with the application of fluorescence lifetime imaging microscopy of Arabidopsis thaliana leaves, wild-type and impaired in chloroplast movements or photoprotective excitation quenching. The results show that both regulatory mechanisms operate over a relatively wide range of light intensities. By contrast, impaired chloroplast translocations have no effect on photoprotection at the molecular level, indicating the direction of information flow in the coupling of these two regulatory mechanisms: from the photosynthetic apparatus to the cellular level. The results show also that the presence of the xanthophyll zeaxanthin is necessary and sufficient for the full development of photoprotective quenching of excessive chlorophyll excitations in plants.


Assuntos
Arabidopsis , Cloroplastos , Cloroplastos/metabolismo , Fotossíntese , Clorofila/metabolismo , Xantofilas/metabolismo
2.
BMC Plant Biol ; 24(1): 55, 2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38238701

RESUMO

BACKGROUND: This study examines the biological implications of an overlap between two sequences in the Arabidopsis genome, the 3'UTR of the PHOT2 gene and a putative AT5G58150 gene, encoded on the complementary strand. AT5G58150 is a probably inactive protein kinase that belongs to the transmembrane, leucine-rich repeat receptor-like kinase family. Phot2 is a membrane-bound UV/blue light photoreceptor kinase. Thus, both proteins share their cellular localization, on top of the proximity of their loci. RESULTS: The extent of the overlap between 3'UTR regions of AT5G58150 and PHOT2 was found to be 66 bp, using RACE PCR. Both the at5g58150 T-DNA SALK_093781C (with insertion in the promoter region) and 35S::AT5G58150-GFP lines overexpress the AT5G58150 gene. A detailed analysis did not reveal any substantial impact of PHOT2 or AT5G58150 on their mutual expression levels in different light and osmotic stress conditions. AT5G58150 is a plasma membrane protein, with no apparent kinase activity, as tested on several potential substrates. It appears not to form homodimers and it does not interact with PHOT2. Lines that overexpress AT5G58150 exhibit a greater reduction in lateral root density due to salt and osmotic stress than wild-type plants, which suggests that AT5G58150 may participate in root elongation and formation of lateral roots. In line with this, mass spectrometry analysis identified proteins with ATPase activity, which are involved in proton transport and cell elongation, as putative interactors of AT5G58150. Membrane kinases, including other members of the LRR RLK family and BSK kinases (positive regulators of brassinosteroid signalling), can also act as partners for AT5G58150. CONCLUSIONS: AT5G58150 is a membrane protein that does not exhibit measurable kinase activity, but is involved in signalling through interactions with other proteins. Based on the interactome and root architecture analysis, AT5G58150 may be involved in plant response to salt and osmotic stress and the formation of roots in Arabidopsis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Regiões 3' não Traduzidas , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Membrana/genética , Fosforilação , Plantas/genética , Proteínas Quinases/genética
3.
Molecules ; 28(5)2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36903479

RESUMO

Forensic science is a field that requires precise and reliable methods for the detection and analysis of evidence. One such method is Fourier Transform Infrared (FTIR) spectroscopy, which provides high sensitivity and selectivity in the detection of samples. In this study, the use of FTIR spectroscopy and statistical multivariate analysis to identify high explosive (HE) materials (C-4, TNT, and PETN) in the residues after high- and low-order explosions is demonstrated. Additionally, a detailed description of the data pre-treatment process and the use of various machine learning classification techniques to achieve successful identification is also provided. The best results were obtained with the hybrid LDA-PCA technique, which was implemented using the R environment, a code-driven open-source platform that promotes reproducibility and transparency.

4.
Molecules ; 27(19)2022 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-36234838

RESUMO

ATR-FTIR (attenuated total reflection-Fourier-transform infrared) microscopy with imaging is widely used in the heritage field to characterise complex compositions of paint cross-sections. However, some limitations include the need for ATR crystal contact with the sample and the inability to resolve particle size below the IR diffraction limit. Recently, a novel O-PTIR (optical-photothermal infrared) spectroscopy technique claimed to open a new avenue for non-invasive, efficient, and reliable analysis at sub-micron resolution. O-PTIR produces transmission-like FTIR spectra for interpretation, without the need to touch the sample, which are highly favourable attributes for analysing heritage samples. This paper reports the comparison of O-PTIR and ATR-FTIR techniques applied to a cross-section embedding a thin paint fragment that delaminated from a late 19th to early 20th-century oil portrait. The hazy paint fragment consisted of zinc soaps (both crystalline and amorphous), gordaite (NaZn4Cl(OH)6SO4·6H2O), and zinc lactate, that could not all be well-resolved with ATR-FTIR imaging. With O-PTIR analysis, the degradation compounds could be resolved at sub-micron resolution with an equivalent or better signal-to-noise ratio. This case study shows how the two techniques can be used to obtain comprehensive information at a broad level with ATR-FTIR and a detailed level with O-PTIR.


Assuntos
Pintura , Sabões , Lactatos , Pintura/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Zinco
5.
Plant Cell Physiol ; 62(4): 693-707, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-33594440

RESUMO

The disruption of the sumoylation pathway affects processes controlled by the two phototropins (phots) of Arabidopsis thaliana, phot1 and phot2. Phots, plant UVA/blue light photoreceptors, regulate growth responses and fast movements aimed at optimizing photosynthesis, such as phototropism, chloroplast relocations and stomatal opening. Sumoylation is a posttranslational modification, consisting of the addition of a SUMO (SMALL UBIQUITIN-RELATED MODIFIER) protein to a lysine residue in the target protein. In addition to affecting the stability of proteins, it regulates their activity, interactions and subcellular localization. We examined physiological responses controlled by phots, phototropism and chloroplast movements, in sumoylation pathway mutants. Chloroplast accumulation in response to both continuous and pulse light was enhanced in the E3 ligase siz1 mutant, in a manner dependent on phot2. A significant decrease in phot2 protein abundance was observed in this mutant after blue light treatment both in seedlings and mature leaves. Using plant transient expression and yeast two-hybrid assays, we found that phots interacted with SUMO proteins mainly through their N-terminal parts, which contain the photosensory LOV domains. The covalent modification in phots by SUMO was verified using an Arabidopsis sumoylation system reconstituted in bacteria followed by the mass spectrometry analysis. Lys 297 was identified as the main target of SUMO3 in the phot2 molecule. Finally, sumoylation of phot2 was detected in Arabidopsis mature leaves upon light or heat stress treatment.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Cloroplastos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Ligases/genética , Ligases/metabolismo , Lisina/metabolismo , Mutação , Fototropismo/genética , Fototropismo/fisiologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , Proteínas Serina-Treonina Quinases/genética , Plântula/genética , Plântula/fisiologia , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Sumoilação
6.
Int J Mol Sci ; 22(4)2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33673252

RESUMO

Senescence is the final stage of plant development, affecting individual organs or the whole organism, and it can be induced by several environmental factors, including shading or darkness. Although inevitable, senescence is a complex and tightly regulated process, ensuring optimal remobilization of nutrients and cellular components from senescing organs. Photoreceptors such as phytochromes and cryptochromes are known to participate in the process of senescence, but the involvement of phototropins has not been studied to date. We investigated the role of these blue light photoreceptors in the senescence of individually darkened Arabidopsis thaliana leaves. We compared several physiological and molecular senescence markers in darkened leaves of wild-type plants and phototropin mutants (phot1, phot2, and phot1phot2). In general, all the symptoms of senescence (lower photochemical activity of photosystem II, photosynthetic pigment degradation, down-regulation of photosynthetic genes, and up-regulation of senescence-associated genes) were less pronounced in phot1phot2, as compared to the wild type, and some also in one of the single mutants, indicating delayed senescence. This points to different mechanisms of phototropin operation in the regulation of senescence-associated processes, either with both photoreceptors acting redundantly, or only one of them, phot1, playing a dominant role.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Complexo de Proteína do Fotossistema II/genética , Folhas de Planta/genética , Proteínas Serina-Treonina Quinases/genética
7.
Anal Chem ; 92(7): 4788-4797, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32125827

RESUMO

The objective of this work was to measure infrared spectra of high explosive materials (HE) in wide spectral range in order to acquire information for their complete characterization and find out the regions that are the most discriminatory for each material. Four HEs were measured by means of Fourier Transform Infrared (FTIR) spectroscopy in a very broad range (from near- via mid- to far-IR). Obtained spectra were subsequently evaluated using multivariate statistical methods for dimension reduction and results grouping. Clustering was assessed in terms of compactness and stability in order to distinguish which region or regions are most suitable for the identification based on spectral signature. Based on outcomes of visualization method (silhouette plot) used to compare results of implemented chemometric methods (HCA, PAM, and PCA) done on FTIR spectra collected for four high explosive materials (PETN, C-4, RDX, and TNT) within all regions, it seems that the mid-IR region is the most informative for the distinction among analyzed HE materials based on substance spectral signatures. However, it is worth noticing that also the near-IR region can be used for good differentiation.

8.
Anal Chem ; 92(14): 9649-9657, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32567834

RESUMO

As we live under a constant threat of global terrorism, the effective detection of highly energetic materials is one of the critical procedures needed at a variety of locations, including airports, border checkpoints, and entrances to high-security buildings. In this work, the application of optical-photothermal infrared (O-PTIR) spectromicroscopy for the detection of highly explosive materials within fingerprints is described. High-explosive (HE) materials (e.g., PETN, RDX, C-4, or TNT) were used to prepare contaminated fingerprints. These were subsequently deposited on various objects, including microscopic glass slides, a table, a mug, etc. Samples deposited on glass slides were directly sent for analyses; for other samples, adhesive tapes were used to lift off fingermarks. In cases of difficulty in locating fingerprints, additional powders were used to enhance their visibility. Experiments were performed with a mIRage IR microscope working in a noncontact, far-field reflection mode, offering submicron IR spectroscopy and imaging. Fast imaging (several characteristic absorbances were selected for every substance of interest) was used to locate "suspicious" particles among various residues present in fingerprints. Subsequently, spectra were collected for those particles. Reflection mode O-PTIR spectra taken from powdered and nonenhanced fingerprints were of comparable quality to transmission mode FTIR spectra collected for pure HEs. On the basis of the performed experiments, we consider O-PTIR spectromicroscopy to open a new avenue for the nondestructive, efficient, and reliable analysis of exogenous substances deposited within fingerprints. The real significance of O-PTIR is in its ability to deliver high-quality, spatially resolved FTIR transmission-like spectra below the diffraction limit of infrared wavelengths, doing so in an easy-to-use reflection (far-field) mode. Collected spectra are also searchable and interpretable in both commercial and institutional IR databases without mathematical modeling.

9.
Photochem Photobiol Sci ; 18(5): 970-988, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30720036

RESUMO

Plants perceive ultraviolet-B (UV-B) radiation through the UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8), and initiate regulatory responses via associated signalling networks, gene expression and metabolic pathways. Various regulatory adaptations to UV-B radiation enable plants to harvest information about fluctuations in UV-B irradiance and spectral composition in natural environments, and to defend themselves against UV-B exposure. Given that UVR8 is present across plant organs and tissues, knowledge of the systemic signalling involved in its activation and function throughout the plant is important for understanding the context of specific responses. Fine-scale understanding of both UV-B irradiance and perception within tissues and cells requires improved application of knowledge about UV-attenuation in leaves and canopies, warranting greater consideration when designing experiments. In this context, reciprocal crosstalk among photoreceptor-induced pathways also needs to be considered, as this appears to produce particularly complex patterns of physiological and morphological response. Through crosstalk, plant responses to UV-B radiation go beyond simply UV-protection or amelioration of damage, but may give cross-protection over a suite of environmental stressors. Overall, there is emerging knowledge showing how information captured by UVR8 is used to regulate molecular and physiological processes, although understanding of upscaling to higher levels of organisation, i.e. organisms, canopies and communities remains poor. Achieving this will require further studies using model plant species beyond Arabidopsis, and that represent a broad range of functional types. More attention should also be given to plants in natural environments in all their complexity, as such studies are needed to acquire an improved understanding of the impact of climate change in the context of plant-UV responses. Furthermore, broadening the scope of experiments into the regulation of plant-UV responses will facilitate the application of UV radiation in commercial plant production. By considering the progress made in plant-UV research, this perspective highlights prescient topics in plant-UV photobiology where future research efforts can profitably be focussed. This perspective also emphasises burgeoning interdisciplinary links that will assist in understanding of UV-B effects across organisational scales and gaps in knowledge that need to be filled so as to achieve an integrated vision of plant responses to UV-radiation.


Assuntos
Folhas de Planta/metabolismo , Plantas/metabolismo , Raios Ultravioleta , Fenômenos Ecológicos e Ambientais
10.
Plant Cell Physiol ; 59(1): 44-57, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29069446

RESUMO

Pyrimidine dimers are the most important DNA lesions induced by UVB irradiation. They can be repaired directly by photoreactivation or indirectly by the excision repair pathways. Photoreactivation is carried out by photolyases, enzymes which bind to the dimers and use the energy of blue light or UVA to split bonds between adjacent pyrimidines. Arabidopsis thaliana has three known photolyases: AtPHR1, AtCRY3 and AtUVR3. Little is known about the cellular localization and regulation of AtUVR3 expression. We have found that its transcript level is down-regulated by light (red, blue or white) in a photosynthesis-dependent manner. The down-regulatory effect of red light is absent in mature leaves of the phyB mutant, but present in leaves of phyAphyB. UVB irradiation does not increase AtUVR3 expression in leaves. Transiently expressed AtUVR3-green fluorescent protein (GFP) is found in the nuclei, chloroplasts and mitochondria of Nicotiana benthamiana epidermal cells. In the nucleoplasm, AtUVR3-GFP is distributed uniformly, while in the nucleolus it forms speckles. Truncated AtUVR3 and muteins were used to identify the sequences responsible for its subcellular localization. Mitochondrial and chloroplast localization of AtUVR3 is independent of its N-terminal sequence. Amino acids located at the C-terminal loop of the protein are involved in its transport into chloroplasts and its retention inside the nucleolus.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Carbono-Carbono Liases/metabolismo , Núcleo Celular/enzimologia , Cloroplastos/enzimologia , Mitocôndrias/enzimologia , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Carbono-Carbono Liases/genética , Nucléolo Celular/genética , Nucléolo Celular/metabolismo , Núcleo Celular/genética , Cloroplastos/genética , Regulação para Baixo/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Luz , Mitocôndrias/genética , Mutação , Fotossíntese/genética , Fotossíntese/efeitos da radiação , Plantas Geneticamente Modificadas , Transporte Proteico
11.
Folia Med Cracov ; 58(1): 25-41, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30079898

RESUMO

OBJECTIVE: The goal of this contribution is to present and familiarize the medical community with the method for the assessment of trace and essentials elements in prostate tissue sections. MATERIALS AND METHODS: X-ray fluorescence based technique(namely Synchrotron Induced X-ray Emission (SRIXE)) is described in terms of methodology, sample preparation and the evaluation of the recorded results (spectral data sets). Materials for the samples were collected from the patients underwent radical prostatectomy due to Adenocarcinoma prostatae. Specimens were freeze-dried, cut by microtome (to the thickness of 15 µm), one slice was placed on Mylar foil (for SRIXE measurements) and adjacent one on microscopic glass (for histopathological assessment). RESULTS: Results presented here show the usability of SRIXE method for the evaluation of concentration of trace and essential elements in prostate tissue sections with the spatial resolution better than 15 microns. DISCUSSION: Histopathological analysis of samples, which is only focused on morphological features, is unable to reveal information about changes in biochemical signature of tissues affected by the illness. SRIXE is a powerful and promising technique to analyse even very low concentrations oat the cellular level without any labelling or separating procedures. Obtained results may be correlated with classic histopathological assessment allowing for drawing conclusions on the changes in certain elements concentrations with the progression of disease. Moreover, mentioned in this work analysis, can be performed for any type of biological tissues.


Assuntos
Adenocarcinoma/patologia , Neoplasias da Próstata/patologia , Oligoelementos/análise , Humanos , Masculino , Prostatectomia , Espectrometria por Raios X/métodos , Síncrotrons , Técnicas de Cultura de Tecidos/métodos
12.
J Exp Bot ; 67(17): 4963-78, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27406783

RESUMO

Phototropins are plant photoreceptors which regulate numerous responses to blue light, including chloroplast relocation. Weak blue light induces chloroplast accumulation, whereas strong light leads to an avoidance response. Two Arabidopsis phototropins are characterized by different light sensitivities. Under continuous light, both can elicit chloroplast accumulation, but the avoidance response is controlled solely by phot2. As well as continuous light, brief light pulses also induce chloroplast displacements. Pulses of 0.1s and 0.2s of fluence rate saturating the avoidance response lead to transient chloroplast accumulation. Longer pulses (up to 20s) trigger a biphasic response, namely transient avoidance followed by transient accumulation. This work presents a detailed study of transient chloroplast responses in Arabidopsis. Phototropin mutants display altered chloroplast movements as compared with the wild type: phot1 is characterized by weaker responses, while phot2 exhibits enhanced chloroplast accumulation, especially after 0.1s and 0.2s pulses. To determine the cause of these differences, the abundance and phosphorylation levels of both phototropins, as well as the interactions between phototropin molecules are examined. The formation of phototropin homo- and heterocomplexes is the most plausible explanation of the observed phenomena. The physiological consequences of this interplay are discussed, suggesting the universal character of this mechanism that fine-tunes plant reactions to blue light. Additionally, responses in mutants of different protein phosphatase 2A subunits are examined to assess the role of protein phosphorylation in signaling of chloroplast movements.


Assuntos
Cloroplastos/fisiologia , Fototropinas/fisiologia , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiologia , Cloroplastos/metabolismo , Cloroplastos/efeitos da radiação , Luz , Fototropinas/metabolismo , Técnicas do Sistema de Duplo-Híbrido
13.
BMC Plant Biol ; 15: 281, 2015 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-26608826

RESUMO

BACKGROUND: Ultraviolet B (UV-B) irradiation can influence many cellular processes. Irradiation with high UV-B doses causes chlorophyll degradation, a decrease in the expression of genes associated with photosynthesis and its subsequent inhibition. On the other hand, sublethal doses of UV-B are used in post-harvest technology to prevent yellowing in storage. To address this inconsistency the effect of short, high-dose UV-B irradiation on detached Arabidopsis thaliana leaves was examined. RESULTS: Two different experimental models were used. After short treatment with a high dose of UV-B the Arabidopsis leaves were either put into darkness or exposed to constant light for up to 4 days. UV-B inhibited dark-induced chlorophyll degradation in Arabidopsis leaves in a dose-dependent manner. The expression of photosynthesis-related genes, chlorophyll content and photosynthetic efficiency were higher in UV-B -treated leaves left in darkness. UV-B treatment followed by constant light caused leaf yellowing and induced the expression of senescence-related genes. Irrespective of light treatment a high UV-B dose led to clearly visible cell death 3 days after irradiation. CONCLUSIONS: High doses of UV-B have opposing effects on leaves depending on their light status after UV treatment. In darkened leaves short UV-B treatment delays the appearance of senescence symptoms. When followed by light treatment, the same doses of UV-B result in chlorophyll degradation. This restricts the potential usability of UV treatment in postharvest technology to crops which are stored in darkness.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Fotossíntese , Folhas de Planta/efeitos da radiação , Raios Ultravioleta , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Escuridão , Luz , Folhas de Planta/metabolismo , Fatores de Tempo
14.
Analyst ; 140(8): 2810-4, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25723954

RESUMO

Pre-processing of Fourier transform infrared (FTIR) spectra is typically the first and crucial step in data analysis. Very often hyperspectral datasets include the regions characterized by the spectra of very low intensity, for example two-dimensional (2D) maps where the areas with only support materials (like mylar foil) are present. In that case segmentation of the complete dataset is required before subsequent evaluation. The method proposed in this contribution is based on a multivariate approach (hierarchical cluster analysis), and shows its superiority when compared to the standard method of cutting-off by using only the mean spectral intensity. Both techniques were implemented and their performance was tested in the R statistical environment - open-source platform - that is a favourable solution if the repeatability and transparency are the key aspects.


Assuntos
Espectroscopia de Infravermelho com Transformada de Fourier , Estatística como Assunto/métodos , Análise por Conglomerados , Análise Multivariada
15.
Nanotechnology ; 26(25): 255201, 2015 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-26041560

RESUMO

Branchlike nano-electrode structures were found to improve the THz emission intensity of a photomixer by approximately one order of magnitude higher than that of a photomixer with one row of nano-electrodes separated by the same 100 nm gap. The enhancement is attributed to a more efficient collection of generated carriers, which is in turn due to a more intense electric field under the branchlike nano-electrodes' structures. This is coupled with an increased number of effective areas where strong tip-to-tip THz field enhancements were observed. The optical-to-THz conversion efficiency of the photomixers with the new branchlike nano-electrodes was found to be 10 times higher. The more efficient THz photomixer will greatly benefit the development of continuous-wave THz imaging and spectroscopy systems.

16.
Anal Chem ; 86(14): 6918-23, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24960413

RESUMO

Assessment of the performance and up-to-date diagnostics of scientific equipment is one of the key components in contemporary laboratories. Most reliable checks are performed by real test experiments while varying the experimental conditions (typically, in the case of infrared spectroscopic measurements, the size of the beam aperture, the duration of the experiment, the spectral range, the scanner velocity, etc.). On the other hand, the stability of the instrument response in time is another key element of the great value. Source stability (or easy predictable temporal changes, similar to those observed in the case of synchrotron radiation-based sources working in non top-up mode), detector stability (especially in the case of liquid nitrogen- or liquid helium-cooled detectors) should be monitored. In these cases, recorded datasets (spectra) include additional variables such as time stamp when a particular spectrum was recorded (in the case of time trial experiments). A favorable approach in evaluating these data is building hyperspectral object that consist of all spectra and all additional parameters at which these spectra were recorded. Taking into account that these datasets could be considerably large in size, there is a need for the tools for semiautomatic data evaluation and information extraction. A comprehensive R archive network--the open-source R Environment--with its flexibility and growing potential, fits these requirements nicely. In this paper, examples of practical implementation of methods available in R for real-life Fourier transform infrared (FTIR) spectroscopic data problems are presented. However, this approach could easily be adopted to many various laboratory scenarios with other spectroscopic techniques.


Assuntos
Interpretação Estatística de Dados , Software , Espectroscopia de Infravermelho com Transformada de Fourier/instrumentação , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Síncrotrons , Desenho de Equipamento , Processamento de Imagem Assistida por Computador , Processamento de Sinais Assistido por Computador , Razão Sinal-Ruído , Vácuo
17.
J Exp Bot ; 65(12): 3263-76, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24821953

RESUMO

Phototropins are plasma membrane-localized UVA/blue light photoreceptors which mediate phototropism, inhibition of primary hypocotyl elongation, leaf positioning, chloroplast movements, and stomatal opening. Blue light irradiation activates the C-terminal serine/threonine kinase domain of phototropin which autophosphorylates the receptor. Arabidopsis thaliana encodes two phototropins, phot1 and phot2. In response to blue light, phot1 moves from the plasma membrane into the cytosol and phot2 translocates to the Golgi complex. In this study the molecular mechanism and route of blue-light-induced phot2 trafficking are demonstrated. It is shown that Atphot2 behaves in a similar manner when expressed transiently under 35S or its native promoter. The phot2 kinase domain but not blue-light-mediated autophosphorylation is required for the receptor translocation. Using co-localization and western blotting, the receptor was shown to move from the cytoplasm to the Golgi complex, and then to the post-Golgi structures. The results were confirmed by brefeldin A (an inhibitor of the secretory pathway) which disrupted phot2 trafficking. An association was observed between phot2 and the light chain2 of clathrin via bimolecular fluorescence complementation. The fluorescence was observed at the plasma membrane. The results were confirmed using co-immunoprecipitation. However, tyrphostin23 (an inhibitor of clathrin-mediated endocytosis) and wortmannin (a suppressor of receptor endocytosis) were not able to block phot2 trafficking, indicating no involvement of receptor endocytosis in the formation of phot2 punctuate structures. Protein turnover studies indicated that the receptor was continuously degraded in both darkness and blue light. The degradation of phot2 proceeded via a transport route different from translocation to the Golgi complex.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Citoplasma/metabolismo , Complexo de Golgi/metabolismo , Luz , Arabidopsis/citologia , Proteínas de Arabidopsis/genética , Imunoprecipitação , Fosforilação , Fosfotransferases/metabolismo , Transporte Proteico/efeitos da radiação
18.
Plant Cell Rep ; 33(1): 165-77, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24135858

RESUMO

KEY MESSAGE: H2O2 is necessary to elicit rhizogenic action of auxin. Activities of specific catalase and manganese superoxide dismutase forms mark roots development. Hypocotyl explants of Mesembryanthemum crystallinum regenerated roots on medium containing 2,4-dichlorophenoxyacetic acid. Explants became competent to respond to the rhizogenic action of auxin on day 3 of culture, when hydrogen peroxide content in cultured tissue was the highest. L-Ascorbic acid added to the medium at 5 µM lowered the H2O2 level, inhibited rhizogenesis and induced non-regenerative callus, suggesting that certain level of H2O2 is required to promote root initiation. Coincident with the onset of rhizogenic determination, meristemoids formed at the periphery of the hypocotyl stele and the activity of the manganese form of superoxide dismutase, MnSOD-2 was induced. Once induced, MnSOD-2 activity was maintained through the post-determination phase of rooting, involving root growth. MnSOD-2 activity was not found in non-rhizogenic explants maintained in the presence of AA. Analyses of the maximum photochemical efficiency of photosystem II and the oxygen uptake rate revealed that the explants were metabolically arrested during the predetermination stage of rhizogenesis. Respiratory and photosynthetic rates were high during root elongation and maturation. Changes in catalase and peroxidase activities correlated with fluctuations of endogenous H2O2 content throughout rhizogenic culture. Expression of a specific CAT-2 form accompanied the post-determination stage of rooting and a high rate of carbohydrate metabolism during root growth. On the other hand, the occurrence of MnSOD-2 activity did not depend on the metabolic status of explants. The expression of MnSOD-2 activity throughout root development seems to relate it specifically to root metabolism and indicates it as a molecular marker of rhizogenesis in M. crystallinum.


Assuntos
Antioxidantes/metabolismo , Peróxido de Hidrogênio/metabolismo , Hipocótilo/crescimento & desenvolvimento , Mesembryanthemum/enzimologia , Mesembryanthemum/crescimento & desenvolvimento , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , Ácido 2,4-Diclorofenoxiacético , Ácido Ascórbico/farmacologia , Catalase/metabolismo , Meios de Cultura/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Guaiacol/farmacologia , Hipocótilo/efeitos dos fármacos , Meristema/efeitos dos fármacos , Meristema/crescimento & desenvolvimento , Mesembryanthemum/efeitos dos fármacos , Oxigênio/metabolismo , Peroxidase/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Raízes de Plantas/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Superóxido Dismutase/metabolismo
20.
BMC Geriatr ; 13: 108, 2013 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-24119004

RESUMO

BACKGROUND: A current topic in the field of geriatrics still needing a great deal of study is the changes in body posture occurring with age. Symptoms of these changes can be observed starting between the ages of 40-50 years with a slow progression that increases after 60 years of age. The aims of this study were to evaluate parameters characterizing the posture of women over the age of 60 years compared with a control group and to determine the dynamics of body posture changes in the following decades. METHODS: The study included 260 randomly selected women. The study group consisted of 130 women between the ages of 60-90 years (Older Women). The control group (Younger Women) consisted of 130 women between the ages of 20-25 years (posture stabilization period). The photogrammetric method was used to evaluate body posture using the phenomenon of the projection chamber. The study was conducted according to generally accepted principles. RESULTS: In the analysis of parameters characterizing individual slope curves, results were varied among different age groups. The lumbar spine slope did not show significant differences between different age groups (p = 0.6952), while statistically significant differences (p = 0.0000) were found in the thoracic-lumbar spine slope (p = 0.0033) and upper thoracic spine slope. Body angle was shown to increase with age (p = 0.0000). Thoracic kyphosis depth significantly deepened with age (p = 0.0002), however, the thoracic kyphosis angle decreased with age (p = 0.0000). An increase in asymmetries was noticed, provided by a significantly higher angle of the shoulder line (p = 0.0199) and the difference in height of the lower shoulder blade angle (p = 0.0007) measurements in the group of older women. CONCLUSIONS: Changes in the parameters describing body posture throughout consecutive decades were observed. Therapy for women over the age of 60 years should involve strengthening of the erector spinae muscles and controlling body posture with the aim of reducing trunk inclination and deepening of thoracic kyphosis. Moreover, exercises shaping lumbar lordosis should be performed to prevent its flattening.


Assuntos
Envelhecimento/patologia , Cifose/diagnóstico , Cifose/terapia , Postura , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Feminino , Humanos , Cifose/epidemiologia , Masculino , Pessoa de Meia-Idade , Postura/fisiologia , Vértebras Torácicas/patologia , Adulto Jovem
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