Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 87
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Molecules ; 28(12)2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37375435

RESUMO

The in vitro cultures of Rindera graeca, a rare endemic plant, were developed as a sustainable source of phenolic acids. Various shoot and root cultures were established and scaled up in a sprinkle bioreactor. A multiplication rate of 7.2 shoots per explant was achieved. HPLC-PDA-ESI-HRMS analysis revealed the presence of rosmarinic acid (RA) and lithospermic acid B (LAB) as the main secondary metabolites in both the shoot and root cultures. The maximum RA (30.0 ± 3.2 mg/g DW) and LAB (49.3 ± 15.5 mg/g DW) yields were determined in root-regenerated shoots. The strongest free radical scavenging activity (87.4 ± 1.1%), according to 2,2-diphenyl-1-picrylhydrazyl-hydrate assay, was noted for roots cultivated in a DCR medium. The highest reducing power (2.3 µM ± 0.4 TE/g DW), determined by the ferric-reducing antioxidant power assay, was noted for shoots cultivated on an SH medium containing 0.5 mg/L 6-benzylaminopurine. A genetic analysis performed using random amplified polymorphic DNA and start codon targeted markers revealed genetic variation of 62.8% to 96.5% among the investigated shoots and roots. This variability reflects the capacity of cultivated shoots and roots to produce phenolic compounds.


Assuntos
Boraginaceae , Boraginaceae/metabolismo , Depsídeos/metabolismo , Cinamatos/metabolismo , Ácido Rosmarínico
2.
Appl Opt ; 61(5): B297-B306, 2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-35201152

RESUMO

Low-level laser therapy (LLLT) is a therapeutic tool that uses the photobiochemical interaction between light and tissue. Its effectiveness is controversial due to a strong dependence on dosimetric parameters. In this work, we demonstrate that digital holographic microscopy is an effective label-free imaging technique to analyze the effects of LLLT on biological cells, and we propose the full methodology to create correct synthetic aperture phase maps for further extensive, highly accurate statistical analysis. The proposed methodology has been designed to provide a basis for many other biological experiments using quantitative phase imaging. We use SHSY-5Y and HaCaT cells irradiated with different doses of red light for the experiment. The analysis shows quantitative changes in cell dry mass density and the projected cell surface in response to different radiation doses.


Assuntos
Holografia , Terapia com Luz de Baixa Intensidade , Holografia/métodos
3.
Int J Mol Sci ; 23(14)2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35887109

RESUMO

Age-related macular degeneration (AMD) is an eye disease causing damage to the macular region of the retina where most of the photoreceptors responsible for central visual acuity are located. MicroRNAs (miRNAs) are small single-stranded non-coding RNA molecules that negatively regulate genes by silent post-transcriptional gene expressions. Previous studies have shown that changes in specific miRNAs are involved in the pathogenesis of eye diseases, including AMD. Altered expressions of miRNAs are related to disturbances of regulating oxidative stress, inflammation, angiogenesis, apoptosis and phagocytosis, which are known factors in the pathogenesis of AMD. Moreover, dysregulation of miRNA is involved in drusen formation. Thus, miRNAs may be used as potential molecular biomarkers for the disease and, furthermore, tailoring therapeutics to particular disturbances in miRNAs may, in the future, offer hope to prevent irreversible vision loss. In this review, we clarify the current state of knowledge about the influence of miRNA on the pathogenesis, diagnosis and treatment of AMD. Our study material consisted of publications, which were found in PubMed, Google Scholar and Embase databases using "Age-related macular degeneration", "miRNA", "AMD biomarkers", "miRNA therapeutics" and "AMD pathogenesis" as keywords. Paper search was limited to articles published from 2011 to date. In the section "Retinal, circulating and vitreous body miRNAs found in human studies", we limited the search to studies with patients published in 2016-2021.


Assuntos
Degeneração Macular , MicroRNAs , Biomarcadores/metabolismo , Humanos , Inflamação/metabolismo , Degeneração Macular/diagnóstico , Degeneração Macular/genética , Degeneração Macular/terapia , MicroRNAs/genética , MicroRNAs/metabolismo , Retina/metabolismo
4.
Proc Natl Acad Sci U S A ; 115(38): 9634-9639, 2018 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-30181278

RESUMO

The plastid terminal oxidase (PTOX) has been shown to be an important sink for photosynthetic electron transport in stress-tolerant plants. However, overexpression studies in stress-sensitive species have previously failed to induce significant activity of this protein. Here we show that overexpression of PTOX from the salt-tolerant brassica species Eutrema salsugineum does not, alone, result in activity, but that overexpressing plants show faster induction and a greater final level of PTOX activity once exposed to salt stress. This implies that an additional activation step is required before activity is induced. We show that that activation involves the translocation of the protein from the unstacked stromal lamellae to the thylakoid grana and a protection of the protein from trypsin digestion. This represents an important activation step and opens up possibilities in the search for stress-tolerant crops.


Assuntos
Brassica/fisiologia , Transporte de Elétrons/fisiologia , Oxirredutases/metabolismo , Proteínas das Membranas dos Tilacoides/metabolismo , Tilacoides/metabolismo , Arabidopsis/genética , Fotossíntese/fisiologia , Plantas Geneticamente Modificadas , Tolerância ao Sal/fisiologia
5.
Nano Lett ; 19(6): 3918-3924, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31117758

RESUMO

Development of protein cages for encapsulation of active enzyme cargoes and their subsequent arrangement into a controllable three-dimensional array is highly desirable. However, cargo capture is typically challenging because of difficulties in achieving reversible assembly/disassembly of protein cages in mild conditions. Herein we show that by using an unusual ferritin cage protein that undergoes triggerable assembly under mild conditions, we can achieve reversible filling with protein cargoes including an active enzyme. We demonstrate that these filled cages can be arrayed in three-dimensional crystal lattices and have an additional chaperone-like effect, increasing both thermostability and enzymatic activity of the encapsulated enzyme.


Assuntos
Proteínas Arqueais/química , Archaeoglobus fulgidus/química , Proteínas de Bactérias/química , Preparações de Ação Retardada/química , Ferritinas/química , Thermotoga maritima/química , Sequência de Aminoácidos , Animais , Estabilidade Enzimática , Enzimas Imobilizadas/administração & dosagem , Enzimas Imobilizadas/química , Proteínas de Fluorescência Verde/administração & dosagem , Proteínas de Fluorescência Verde/química , Modelos Moleculares , Muramidase/administração & dosagem , Muramidase/química , Nanoestruturas/química , Ligação Proteica , Dobramento de Proteína
6.
Przegl Epidemiol ; 74(1): 69-87, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32500988

RESUMO

Symptomatic Clostridium difficile infection (CDI) is an acute inflammatory disease of the gastrointestinal tract, manifesting in at least 3 unformed stools within 24 hours. Predicting factors for CDI include contact with medical care (mainly hospitalization), antibiotic therapy in the last 12 weeks, use of proton pump inhibitors (PPI), H2 blockers, cancer chemotherapy, especially in the neutropenia stage, gastrointestinal surgery, advanced age and concomitant chronic diseases (renal failure, liver failure, chronic inflammatory bowel disease - especially ulcerative bowel disease, cancer, HIV infection, cachexia and hypoalbuminaemia) and vitamin D deficiency. Clinical classification distinguishes three types of CDI - mild / moderate, severe, and fulminant. The principles of treatment of the first and subsequent CDI incidents depending on the clinical course are based on oral vancomycin. CDI is recurrent. The basis for treating CDI relapses is vancomycin administered orally at a dose of 4x125 mg for 10 days followed by concomitant vancomycin dose reduction therapy. The use of fecal microbiota transfer (FMT) in the treatment of CDI relapses is considered to be the most effective therapy for recurrent CDI. An indication for FMT is antibiotic-resistant C. difficile infection, regardless of the number of incidents CDI. The panel of tests recommended for a bacterial flora donor is presented in the recommendations.


Assuntos
Infecções por Clostridium/terapia , Transplante de Microbiota Fecal , Antibacterianos , Clostridioides difficile , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Microbioma Gastrointestinal , Humanos , Microbiota , Polônia/epidemiologia , Guias de Prática Clínica como Assunto , Resultado do Tratamento
7.
Crit Rev Biotechnol ; 38(4): 559-572, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28937283

RESUMO

In the past decade, various strategies to improve photosynthesis and crop yield, such as leaf morphology, light interception and use efficiency, biochemistry of light reactions, stomatal conductance, carboxylation efficiency, and source to sink regulation, have been discussed at length. Leaf morphology and physiology are tightly coupled to light capturing efficiency, gas exchange capacity, and temperature regulation. However, apart from the photoprotective mechanism of photosystem-II (PSII), i.e. non-photochemical quenching, very low genetic variation in the components of light reactions has been observed in plants. In the last decade, biochemistry-based enhancement of carboxylation efficiency that improves photosynthesis in plants was one of the potential strategies for improving plant biomass production. Enhancement of activation of the ubiquitous enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) by Rubisco activase may be another potential strategy for improving a photosynthesis-driven increase in crop yield. Rubisco activase modifies the conformation of the active center in Rubisco by removing tightly bound inhibitors, thereby contributing to enzyme activation and rapid carboxylation. Thermophilic cyanobacteria are oxygenic photosynthetic bacteria that thrive in high-temperature environments. This critical review discusses the prospects for and the potential of engineering Rubisco activase from thermophilic cyanobacteria into temperature-sensitive plants, to increase the threshold temperature and survival of these plants in arid regions.


Assuntos
Proteínas de Arabidopsis/metabolismo , Cianobactérias/metabolismo , Plantas/metabolismo , Biomassa , Ativação Enzimática/fisiologia , Temperatura Alta , Humanos , Fotossíntese/fisiologia , Proteínas de Plantas/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo
8.
Nanotechnology ; 29(2): 025702, 2018 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-29130898

RESUMO

Nanostructures as color-tunable luminescent markers have become major, promising tools for bioimaging and biosensing. In this paper separated molybdate/Gd2O3 doped rare earth ions (erbium, Er3+ and ytterbium, Yb3+) core-shell nanoparticles (NPs), were fabricated by a one-step homogeneous precipitation process. Emission properties were studied by cathodo- and photoluminescence. Scanning electron and transmission electron microscopes were used to visualize and determine the size and shape of the NPs. Spherical NPs were obtained. Their core-shell structures were confirmed by x-ray diffraction and energy-dispersive x-ray spectroscopy measurements. We postulated that the molybdate rich core is formed due to high segregation coefficient of the Mo ion during the precipitation. The calcination process resulted in crystallization of δ/ξ (core/shell) NP doped Er and Yb ions, where δ-gadolinium molybdates and ξ-molybdates or gadolinium oxide. We confirmed two different upconversion mechanisms. In the presence of molybdenum ions, in the core of the NPs, Yb3+-[Formula: see text] (∣2F7/2, 3T2〉) dimers were formed. As a result of a two 980 nm photon absorption by the dimer, we observed enhanced green luminescence in the upconversion process. However, for the shell formed by the Gd2O3:Er, Yb NPs (without the Mo ions), the typical energy transfer upconversion takes place, which results in red luminescence. We demonstrated that the NPs were transported into cytosol of the HeLa and astrocytes cells by endocytosis. The core-shell NPs are sensitive sensors for the environment prevailing inside (shorter luminescence decay) and outside (longer luminescence decay) of the tested cells. The toxicity of the NPs was examined using MTT assay.


Assuntos
Érbio/química , Gadolínio/química , Substâncias Luminescentes/química , Molibdênio/química , Nanopartículas/química , Imagem Óptica/métodos , Itérbio/química , Astrócitos/citologia , Células HeLa , Humanos , Medições Luminescentes/métodos , Microscopia Confocal/métodos , Nanopartículas/ultraestrutura , Nanotecnologia/métodos
9.
Biochim Biophys Acta ; 1848(1 Pt A): 60-6, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25306967

RESUMO

Studies of the membrane proteins suggest their close interaction with the lipid surroundings. Membrane proteins and their activities are affected by the composition and structure of the lipid bilayer. therefore adequate surroundings for studied protein are crucial for the model membrane to ensure its biological relevance. In recent years nanodiscs which are small fragments of lipid bilayer stabilised by derivatives of apolipoprotein, called membrane scaffold protein ( MSP), have been established as alternative tool in structural and functional studies of membrane proteins. In this study, the influence MSP of different length on structure and dynamics of DMPC and POPC bilayer was investigated and compared to bilayer present in liposomes. EPR spectroscopy technique using different PC-based spin probes was employed to show cholesterol-like organising effect of MSPs on lipid bilayer, thus giving a better insight into the nanodiscs model membrane structure, and its possible implications in the research of membrane protein applications.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Bicamadas Lipídicas/química , Lipossomos/química , Nanoestruturas/química , Algoritmos , Apolipoproteína A-I/química , Apolipoproteína A-I/metabolismo , Dimiristoilfosfatidilcolina/química , Dimiristoilfosfatidilcolina/metabolismo , Cinética , Bicamadas Lipídicas/metabolismo , Lipossomos/metabolismo , Fluidez de Membrana , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo
10.
Plant Cell Physiol ; 57(7): 1387-1396, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26936791

RESUMO

A plastid-localized terminal oxidase, PTox, was first described due to its role in chloroplast development, with plants lacking PTox producing white sectors on their leaves. This phenotype is explained as being due to PTox playing a role in carotenoid biosynthesis, as a cofactor of phytoene desaturase. Co-occurrence of PTox with a chloroplast-localized NADPH dehydrogenase (NDH) has suggested the possibility of a functional respiratory pathway in plastids. Evidence has also been found that, in certain stress-tolerant plant species, PTox can act as an electron acceptor from PSII, making it a candidate for engineering stress-tolerant crops. However, attempts to induce such a pathway via overexpression of the PTox protein have failed to date. Here we review the current understanding of PTox function in higher plants and discuss possible barriers to inducing PTox activity to improve stress tolerance.


Assuntos
Adaptação Fisiológica , Oxirredutases/metabolismo , Fenômenos Fisiológicos Vegetais , Plastídeos/enzimologia , Estresse Fisiológico , Transporte de Elétrons , Oxirredutases/química
11.
Postepy Biochem ; 62(2): 158-161, 2016.
Artigo em Polonês | MEDLINE | ID: mdl-28132467

RESUMO

Mitochondria are not only ATP producing organelles, but they play pivotal roles in apoptosis, neurodegeneration, cancer and aging. Mammalian mitochondrial genome is a small DNA molecule of about 16.5 kb, encoding less than 20 polypeptides and a set of ribosomal RNAs and tRNAs. In order to ensure proper cell functioning a continous communication between cell nucleus and mitochondria must be maintained. This review presents novel developments in the field of nucleo-mitochondrial communications. We discuss the import of regulatory cytosolic miRNAs into mitochondria, export of RNA from mitochondria, the existence of novel 3 polypeptides encoded by the mitochondrial genome and the transfer of mitochondrial DNA to nuclear genomes. Mechanisms of these processes and their significance for cellular homeostasis are poorly known and present an important challenge for molecular biology.


Assuntos
Núcleo Celular/metabolismo , Regulação da Expressão Gênica , Mitocôndrias/metabolismo , Transdução de Sinais , Animais , Transporte Biológico , Núcleo Celular/fisiologia , Cromossomos , DNA Mitocondrial/metabolismo , Eucariotos/metabolismo , Eucariotos/fisiologia , Genoma Mitocondrial , Humanos , Mitocôndrias/patologia , Proteínas Mitocondriais/metabolismo , RNA/metabolismo
12.
Nucleic Acids Res ; 41(2): 1223-40, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23221631

RESUMO

RNA decay is usually mediated by protein complexes and can occur in specific foci such as P-bodies in the cytoplasm of eukaryotes. In human mitochondria nothing is known about the spatial organization of the RNA decay machinery, and the ribonuclease responsible for RNA degradation has not been identified. We demonstrate that silencing of human polynucleotide phosphorylase (PNPase) causes accumulation of RNA decay intermediates and increases the half-life of mitochondrial transcripts. A combination of fluorescence lifetime imaging microscopy with Förster resonance energy transfer and bimolecular fluorescence complementation (BiFC) experiments prove that PNPase and hSuv3 helicase (Suv3, hSuv3p and SUPV3L1) form the RNA-degrading complex in vivo in human mitochondria. This complex, referred to as the degradosome, is formed only in specific foci (named D-foci), which co-localize with mitochondrial RNA and nucleoids. Notably, interaction between PNPase and hSuv3 is essential for efficient mitochondrial RNA degradation. This provides indirect evidence that degradosome-dependent mitochondrial RNA decay takes place in foci.


Assuntos
RNA Helicases DEAD-box/metabolismo , Endorribonucleases/metabolismo , Mitocôndrias/enzimologia , Complexos Multienzimáticos/metabolismo , Polirribonucleotídeo Nucleotidiltransferase/metabolismo , RNA Helicases/metabolismo , Estabilidade de RNA , RNA/metabolismo , Trifosfato de Adenosina/metabolismo , Processos de Crescimento Celular , Linhagem Celular , RNA Helicases DEAD-box/análise , DNA Mitocondrial/análise , Inativação Gênica , Humanos , Proteínas Mitocondriais/metabolismo , Polirribonucleotídeo Nucleotidiltransferase/análise , Polirribonucleotídeo Nucleotidiltransferase/genética , RNA/análise , RNA Mitocondrial
13.
BMC Oral Health ; 15(1): 146, 2015 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-26581876

RESUMO

BACKGROUND: The present study aimed at 3D analysis of adhesive remnants and enamel loss following the debonding of orthodontic molar tubes and orthodontic clean-up to assess the effectiveness and safety of One-Step Finisher and Polisher and Adhesive Residue Remover in comparison to tungsten carbide bur. MATERIALS AND METHODS: Thirty human molars were bonded with chemical-cure orthodontic adhesive (Unite, 3M, USA), stored 24 h in 0.9 % saline solution, debonded and cleaned using three methods (Three groups of ten): tungsten carbide bur (Dentaurum, Pforzheim, Germany), one-step finisher and polisher (One gloss, Shofu Dental, Kyoto, Japan) and Adhesive Residue Remover (Dentaurum, Pforzheim, Germany). Direct 3D scanning in blue-light technology to the nearest 2 µm was performed before etching and after adhesive removal. Adhesive remnant height and volume as well as enamel loss depth and volume were calculated. An index of effectiveness and safety was proposed and calculated for every tool; adhesive remnant volume and duplicated enamel lost volume were divided by a sum of multiplicands. Comparisons using parametric ANOVA or nonparametric ANOVA rank Kruskal-Wallis tests were used to compare between tools for adhesive remnant height and volume, enamel loss depth and volume as well as for the proposed index. RESULTS: No statistically significant differences in the volume (p = 0.35) or mean height (p = 0.24) of adhesive remnants were found (ANOVA rank Kruskal-Wallis test) between the groups of teeth cleaned using different tools. Mean volume of enamel loss was 2.159 mm(3) for tungsten carbide bur, 1.366 mm(3) for Shofu One Gloss and 0.659 mm(3) for Adhesive Residue Remover - (F = 2.816, p = 0.0078). A comparison of the proposed new index between tools revealed highly statistically significant differences (p = 0.0081), supporting the best value for Adhesive Residue Remover and the worst - for tungsten carbide bur. CONCLUSIONS: The evaluated tools were all characterized by similar effectiveness. The most destructive tool with regards to enamel was the tungsten carbide bur, and the least was Adhesive Residue Removal.


Assuntos
Cimentos Dentários , Esmalte Dentário , Polimento Dentário , Polimento Dentário/instrumentação , Humanos , Dente Molar , Compostos de Tungstênio
14.
Biochim Biophys Acta ; 1829(8): 842-53, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23454114

RESUMO

Mitochondria are semiautonomous organelles which contain their own genome. Both maintenance and expression of mitochondrial DNA require activity of RNA and DNA helicases. In Saccharomyces cerevisiae the nuclear genome encodes four DExH/D superfamily members (MSS116, SUV3, MRH4, IRC3) that act as helicases and/or RNA chaperones. Their activity is necessary for mitochondrial RNA splicing, degradation, translation and genome maintenance. In humans the ortholog of SUV3 (hSUV3, SUPV3L1) so far is the best described mitochondrial RNA helicase. The enzyme, together with the matrix-localized pool of PNPase (PNPT1), forms an RNA-degrading complex called the mitochondrial degradosome, which localizes to distinct structures (D-foci). Global regulation of mitochondrially encoded genes can be achieved by changing mitochondrial DNA copy number. This way the proteins involved in its replication, like the Twinkle helicase (c10orf2), can indirectly regulate gene expression. Here, we describe yeast and human mitochondrial helicases that are directly involved in mitochondrial RNA metabolism, and present other helicases that participate in mitochondrial DNA replication and maintenance. This article is part of a Special Issue entitled: The Biology of RNA helicases - Modulation for life.


Assuntos
Mitocôndrias/enzimologia , Mitocôndrias/genética , RNA Helicases/genética , RNA Helicases/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , DNA Helicases/genética , DNA Helicases/metabolismo , Replicação do DNA , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Humanos , Mitocôndrias/metabolismo , RNA/genética , RNA/metabolismo , Splicing de RNA , RNA Mitocondrial , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
15.
EMBO J ; 29(14): 2342-57, 2010 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-20531386

RESUMO

The eukaryotic RNA exosome is a ribonucleolytic complex involved in RNA processing and turnover. It consists of a nine-subunit catalytically inert core that serves a structural function and participates in substrate recognition. Best defined in Saccharomyces cerevisiae, enzymatic activity comes from the associated subunits Dis3p (Rrp44p) and Rrp6p. The former is a nuclear and cytoplasmic RNase II/R-like enzyme, which possesses both processive exo- and endonuclease activities, whereas the latter is a distributive RNase D-like nuclear exonuclease. Although the exosome core is highly conserved, identity and arrangements of its catalytic subunits in different vertebrates remain elusive. Here, we demonstrate the association of two different Dis3p homologs--hDIS3 and hDIS3L--with the human exosome core. Interestingly, these factors display markedly different intracellular localizations: hDIS3 is mainly nuclear, whereas hDIS3L is strictly cytoplasmic. This compartmental distribution reflects the substrate preferences of the complex in vivo. Both hDIS3 and hDIS3L are active exonucleases; however, only hDIS3 has retained endonucleolytic activity. Our data suggest that three different ribonucleases can serve as catalytic subunits for the exosome in human cells.


Assuntos
Exossomos/metabolismo , Isoenzimas/metabolismo , Subunidades Proteicas/metabolismo , Ribonucleases/metabolismo , Sequência de Aminoácidos , Exorribonucleases/genética , Exorribonucleases/metabolismo , Complexo Multienzimático de Ribonucleases do Exossomo , Exossomos/química , Teste de Complementação Genética , Células HeLa , Humanos , Isoenzimas/genética , Dados de Sequência Molecular , Subunidades Proteicas/genética , Ribonucleases/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Alinhamento de Sequência
16.
Physiol Plant ; 152(2): 389-401, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24666264

RESUMO

Sorghum is one of the most drought tolerant crops but surprisingly, little is known about the mechanisms achieving this. We have compared physiological and biochemical responses to drought in two sorghum cultivars with contrasting drought tolerance. These closely related cultivars have starkly contrasting responses to water deficit. In the less tolerant Samsorg 40, drought induced progressive loss of photosynthesis. The more drought tolerant Samsorg 17 maintained photosynthesis, transpiration and chlorophyll content until the most extreme conditions. In Samsorg 40, there was a highly specific down-regulation of selected proteins, with loss of PSII and Rubisco but maintenance of PSI and cytochrome b6 f, allowing plants to maintain ATP synthesis. The nitrogen released allows for accumulation of glycine betaine and proline. To the best of our knowledge, this is the first example of specific reengineering of the photosynthetic apparatus in response to drought. In contrast, in Samsorg 17 we detected no substantial change in the photosynthetic apparatus. Rather, plants showed constitutively high soluble sugar concentration, enabling them to maintain transpiration and photosynthesis, even in extremely dry conditions. The implications for these strikingly contrasted strategies are discussed in relation to agricultural and natural systems.


Assuntos
Adaptação Fisiológica , Secas , Sorghum/fisiologia , Betaína/metabolismo , Carbono/metabolismo , Clorofila/metabolismo , Fluorescência , Nitrogênio/metabolismo , Fotossíntese , Complexo de Proteína do Fotossistema I/metabolismo , Proteínas de Plantas/metabolismo , Estômatos de Plantas/fisiologia , Prolina/metabolismo , Água
17.
Materials (Basel) ; 17(3)2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38591491

RESUMO

From an engineering point of view, it is important to know the factors influencing the frost resistance of rocks with porosity above 2% due to their different frost resistance. The article focused on frost durability research using the thermoporometry method (TMP) and the assessment of water phase transition in the pore spaces of selected rocks. For this purpose, the differential scanning calorimetry method (DSC) was used with the adoption of an original algorithm for eliminating the thermal inertia of the measurement system. The results of the DSC method were supplemented with the results of pore size distribution using the mercury intrusion porosimetry method (MIP) and standard rock frost resistance tests. Based on the research carried out using the thermoporometry method, it was confirmed that the ability of water to freeze in the temperature range from -5 °C to -20 °C was important, as well as the ability of rocks to increase the degree of water saturation during freeze-thaw cycles. Based on calorimetric tests combined with thermoporometry, in the case of non-frost-resistant rocks, a significant (dominant) share of pores with a radius of under 10 nm (amounting to over 0.008 cm3/cm3) was found. Pore connections in the water freezing process do not influence the investigated rocks' frost resistance.

18.
Sci Rep ; 14(1): 1446, 2024 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-38228714

RESUMO

Peroxidases (PRXs) play multifaceted roles in plant growth, development, and stress responses. Here, we present a comprehensive analysis of the PRX gene family in guava, a globally significant fruit. In the guava genome, we identified 37 PRX genes, a number lower than that of Arabidopsis, suggesting a distinctive gene family expansion pattern. Phylogenetic analysis unveiled close relationships with Arabidopsis PRXs, with 12 PgPRX genes forming ortholog pairs, indicating a specific expansion pattern. Predictions placed most PRX proteins in the chloroplast and extracellular regions. Structural analysis of PgPRX proteins revealed commonalities in domain structures and motif organization. Synteny analysis underscored the dynamic role of segmental duplication in the evolution of guava's PRX genes. We explored the dynamic expression of PgPRX genes across guava tissues, exposing functional diversity. Furthermore, we examined changes in peroxidase levels and gene expressions during postharvest fruit storage, providing insights for preserving fruit quality. This study offers an initial genome-wide identification and characterization of Class III peroxidases in guava, laying the foundation for future functional analyses.


Assuntos
Arabidopsis , Psidium , Psidium/genética , Arabidopsis/genética , Filogenia , Genômica , Peroxidases/genética , Família Multigênica , Proteínas de Plantas/genética , Proteínas de Plantas/química , Regulação da Expressão Gênica de Plantas , Genoma de Planta
19.
Biochim Biophys Acta ; 1819(9-10): 1027-34, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22178375

RESUMO

Expression of mitochondrially encoded genes must be finely tuned according to the cell's requirements. Since yeast and human mitochondria have limited possibilities to regulate gene expression by altering the transcription initiation rate, posttranscriptional processes, including RNA degradation, are of great importance. In both organisms mitochondrial RNA degradation seems to be mostly depending on the RNA helicase Suv3. Yeast Suv3 functions in cooperation with Dss1 ribonuclease by forming a two-subunit complex called the mitochondrial degradosome. The human ortholog of Suv3 (hSuv3, hSuv3p, SUPV3L1) is also indispensable for mitochondrial RNA decay but its ribonucleolytic partner has so far escaped identification. In this review we summarize the current knowledge about RNA degradation in human and yeast mitochondria. This article is part of a Special Issue entitled: Mitochondrial Gene Expression.


Assuntos
Regulação da Expressão Gênica , Mitocôndrias , Estabilidade de RNA/genética , RNA , Trifosfato de Adenosina/metabolismo , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Exorribonucleases/genética , Exorribonucleases/metabolismo , Humanos , Mitocôndrias/genética , RNA/genética , RNA/metabolismo , RNA Mitocondrial , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
20.
Nanotechnology ; 24(23): 235702, 2013 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-23669145

RESUMO

An effective, simple and practically useful method to incorporate fluorescent nanoparticles inside live biological cells was developed. The internalization time and concentration dependence of a frequently used liposomal transfection factor (Lipofectamine 2000) was studied. A user friendly, one-step technique to obtain water and organic solvent soluble Er(3+) and Yb(3+) doped NaYF4 nanoparticles coated with polyvinylpyrrolidone was obtained. Structural analysis of the nanoparticles confirmed the formation of nanocrystals of the desired sizes and spectral properties. The internalization of NaYF4 nanoparticles in HeLa cervical cancer cells was determined at different nanoparticle concentrations and for incubation periods from 3 to 24 h. The images revealed a redistribution of nanoparticles inside the cell, which increases with incubation time and concentration levels, and depends on the presence of the transfection factor. The study identifies, for the first time, factors responsible for an effective endocytosis of the up-converting nanoparticles to HeLa cells. Thus, the method could be applied to investigate a wide range of future 'smart' theranostic agents. Nanoparticles incorporated into the liposomes appear to be very promising fluorescent probes for imaging real-time cellular dynamics.


Assuntos
Endocitose , Érbio/metabolismo , Fluoretos/metabolismo , Nanopartículas/química , Itérbio/metabolismo , Ítrio/metabolismo , Células HeLa , Humanos , Luminescência , Microscopia Confocal , Nanopartículas/ultraestrutura , Tamanho da Partícula , Espectrometria de Fluorescência , Coloração e Rotulagem , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA