Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Planta ; 259(1): 14, 2023 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-38070043

RESUMO

MAIN CONCLUSION: Understanding BEL transcription factors roles in potato and tomato varies considerably with little overlap. The review suggests reciprocal use of gained results to proceed with the knowledge in both crops The proper development of organs that plants use for reproduction, like fruits or tubers, is crucial for the survival and competitiveness of the species and thus subject to strict regulations. Interestingly, the controls of potato (Solanum tuberosum) tuber and tomato (S. lycopersicum) fruit development use common mechanisms, including the action of the BEL transcription factors (TFs). Although more than ten BEL genes have been identified in either genome, only a few of them have been characterized. The review summarizes knowledge of BEL TFs' roles in these closely related Solanaceae species, focusing on those that are essential for tuberization in potato, namely StBEL5, StBEL11 and StBEL29, and for fruit development in tomato - SlBEL11, SlBL2 and SIBL4. Comprehension of the roles of individual BEL TFs, however, is not yet sufficient. Different levels of understanding of important characteristics are described, such as BEL transcript accumulation patterns, their mobility, BEL protein interaction with KNOX partners, subcellular localisation, and their target genes during initiation and development of the organs in question. A comparison of the knowledge on BEL TFs and their mechanisms of action in potato and tomato may provide inspiration for faster progress in the study of both models through the exchange of information and ideas. Both crops are extremely important for human nutrition. In addition, their production is likely to be threatened by the upcoming climate change, so there is a particular need for breeding using a deep knowledge of control mechanisms.


Assuntos
Solanum lycopersicum , Solanum tuberosum , Humanos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Melhoramento Vegetal , Tubérculos/genética , Tubérculos/metabolismo , Solanum tuberosum/genética , Solanum tuberosum/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Verduras/metabolismo , Solanum lycopersicum/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas
2.
Arch Toxicol ; 97(10): 2587-2607, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37612377

RESUMO

"Novichok" refers to a new group of nerve agents called the A-series agents. Their existence came to light in 2018 after incidents in the UK and again in 2020 in Russia. They are unique organophosphorus-based compounds developed during the Cold War in a program called Foliant in the USSR. This review is based on original chemical entities from Mirzayanov's memoirs published in 2008. Due to classified research, a considerable debate arose about their structures, and hence, various structural moieties were speculated. For this reason, the scientific literature is highly incomplete and, in some cases, contradictory. This review critically assesses the information published to date on this class of compounds. The scope of this work is to summarize all the available and relevant information, including the physicochemical properties, chemical synthesis, mechanism of action, toxicity, pharmacokinetics, and medical countermeasures used to date. The environmental stability of A-series agents, the lack of environmentally safe decontamination, their high toxicity, and the scarcity of information on post-contamination treatment pose a challenge for managing possible incidents.


Assuntos
Contaminação de Medicamentos , Agentes Neurotóxicos , Agentes Neurotóxicos/toxicidade , Compostos Organofosforados
3.
ACS Nano ; 17(11): 10423-10430, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37220255

RESUMO

Antiferromagnets are promising materials for future opto-spintronic applications since they show spin dynamics in the THz range and no net magnetization. Recently, layered van der Waals (vdW) antiferromagnets have been reported, which combine low-dimensional excitonic properties with complex spin-structure. While various methods for the fabrication of vdW 2D crystals exist, formation of large area and continuous thin films is challenging because of either limited scalability, synthetic complexity, or low opto-spintronic quality of the final material. Here, we fabricate centimeter-scale thin films of the van der Waals 2D antiferromagnetic material NiPS3, which we prepare using a crystal ink made from liquid phase exfoliation (LPE). We perform statistical atomic force microscopy (AFM) and scanning electron microscopy (SEM) to characterize and control the lateral size and number of layers through this ink-based fabrication. Using ultrafast optical spectroscopy at cryogenic temperatures, we resolve the dynamics of photoexcited excitons. We find antiferromagnetic spin arrangement and spin-entangled Zhang-Rice multiplet excitons with lifetimes in the nanosecond range, as well as ultranarrow emission line widths, despite the disordered nature of our films. Thus, our findings demonstrate scalable thin-film fabrication of high-quality NiPS3, which is crucial for translating this 2D antiferromagnetic material into spintronic and nanoscale memory devices and further exploring its complex spin-light coupled states.

4.
Arch Toxicol ; 97(1): 39-72, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36335468

RESUMO

Organophosphorus compounds (OP) are a constant problem, both in the military and in the civilian field, not only in the form of acute poisoning but also for their long-lasting consequences. No antidote has been found that satisfactorily protects against the toxic effects of organophosphates. Likewise, there is no universal cure to avert damage after poisoning. The key mechanism of organophosphate toxicity is the inhibition of acetylcholinesterase. The overstimulation of nicotinic or muscarinic receptors by accumulated acetylcholine on a synaptic cleft leads to activation of the glutamatergic system and the development of seizures. Further consequences include generation of reactive oxygen species (ROS), neuroinflammation, and the formation of various other neuropathologists. In this review, we present neuroprotection strategies which can slow down the secondary nerve cell damage and alleviate neurological and neuropsychiatric disturbance. In our opinion, there is no unequivocal approach to ensure neuroprotection, however, sooner the neurotoxicity pathway is targeted, the better the results which can be expected. It seems crucial to target the key propagation pathways, i.e., to block cholinergic and, foremostly, glutamatergic cascades. Currently, the privileged approach oriented to stimulating GABAAR by benzodiazepines is of limited efficacy, so that antagonizing the hyperactivity of the glutamatergic system could provide an even more efficacious approach for terminating OP-induced seizures and protecting the brain from permanent damage. Encouraging results have been reported for tezampanel, an antagonist of GluK1 kainate and AMPA receptors, especially in combination with caramiphen, an anticholinergic and anti-glutamatergic agent. On the other hand, targeting ROS by antioxidants cannot or already developed neuroinflammation does not seem to be very productive as other processes are also involved.


Assuntos
Síndromes Neurotóxicas , Intoxicação por Organofosfatos , Humanos , Acetilcolinesterase/metabolismo , Espécies Reativas de Oxigênio , Organofosfatos , Doenças Neuroinflamatórias , Síndromes Neurotóxicas/etiologia , Síndromes Neurotóxicas/prevenção & controle , Intoxicação por Organofosfatos/tratamento farmacológico , Intoxicação por Organofosfatos/prevenção & controle , Convulsões , Inibidores da Colinesterase/toxicidade
5.
Inorg Chem ; 61(31): 12425-12432, 2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35877186

RESUMO

Since the first synthesis of germanane (GeH) reported in 2013, two-dimensional germanium-based materials have been intensively studied. Over the past decade, several methodologies for the functionalization of germanane have been introduced. The first approach utilized exfoliation of Zintl phase CaGe2 with alkyl halides. Liu's solvothermal method was used for the synthesis of methyl germanane. Another methodology utilized Ge-H activation with sodium naphthalenide and its subsequent alkylation. All of these methods provide functionalized germananes; thus, a comparison of these methods is needed. In this paper, such a comparison of current synthetic approaches towards alkyl germananes is reported, and additionally, a new method for Ge-H activation utilizing a NaK equimolar alloy is presented as a fourth approach. For this purpose, eight alkyl reagents were chosen representing reactive benzyl bromides as well as linear esters and nitriles because they contain easily trackable functional groups. The materials were characterized using Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis, and the data were compared. The comparison of all methods revealed not only some drawbacks for each method but also their advantages. The method utilizing sodium naphthalenide provided the lowest degree of surface coverage, whereas the solvothermal method seemed to provide materials with the highest degree of functionalization; unfortunately, the functionalization was also accompanied by a high degree of surface oxidation, i.e., (Ge-OH/Ge═O) formation. The highest degree of surface coverage accompanied by the lowest degree of surface oxidation was achieved employing Goldberger's phase transfer direct exfoliation of CaGe2 as well as Ge-H activation using the NaK alloy with subsequent alkylation.

7.
Biomolecules ; 11(1)2020 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-33375115

RESUMO

Alzheimer's disease (AD) is a complex disorder with unknown etiology. Currently, only symptomatic therapy of AD is available, comprising cholinesterase inhibitors and N-methyl-d-aspartate (NMDA) receptor antagonists. Drugs targeting only one pathological condition have generated only limited efficacy. Thus, combining two or more therapeutic interventions into one molecule is believed to provide higher benefit for the treatment of AD. In the presented study, we designed, synthesized, and biologically evaluated 15 novel fluoren-9-amine derivatives. The in silico prediction suggested both the oral availability and permeation through the blood-brain barrier (BBB). An initial assessment of the biological profile included determination of the cholinesterase inhibition and NMDA receptor antagonism at the GluN1/GluN2A and GluN1/GluN2B subunits, along with a low cytotoxicity profile in the CHO-K1 cell line. Interestingly, compounds revealed a selective butyrylcholinesterase (BChE) inhibition pattern with antagonistic activity on the NMDARs. Their interaction with butyrylcholinesterase was elucidated by studying enzyme kinetics for compound 3c in tandem with the in silico docking simulation. The docking study showed the interaction of the tricyclic core of new derivatives with Trp82 within the anionic site of the enzyme in a similar way as the template drug tacrine. From the kinetic analysis, it is apparent that 3c is a competitive inhibitor of BChE.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Butirilcolinesterase/genética , Inibidores da Colinesterase/farmacologia , Receptores de N-Metil-D-Aspartato/genética , Doença de Alzheimer/enzimologia , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Butirilcolinesterase/química , Butirilcolinesterase/efeitos dos fármacos , Células CHO , Inibidores da Colinesterase/química , Simulação por Computador , Cricetulus , Inibidores Enzimáticos/farmacologia , Fluorenos/química , Fluorenos/farmacologia , Humanos , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores
8.
Bioorg Chem ; 103: 104179, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32891860

RESUMO

YNT-185 is the first known small molecule acting as orexin 2 receptor (OX2R) agonist with implication to narcolepsy treatment, served as a template scaffold in generating a small set of seven compounds with predictive affinity to OX2R. The design of the new small molecules was driven mostly by improving physicochemical properties of the parent drug YNT-185 in parallel with in silico studies, later suggesting their favorable binding modes within the active site of OX2R. We obtained seven new potential OX2R binders that were evaluated in vitro for their CNS availability, cytotoxicity, and behavior pattern on OX2R. Out of them, 15 emerged as the most potent modulator of OX2R, which, contrary to YNT-185, displayed inverse mode of action, i.e. antagonist profile. 15 was also submitted to an in vivo experiment revealing its ability to permeate through BBB into the brain with a short half-life.


Assuntos
Compostos de Anilina/uso terapêutico , Benzamidas/uso terapêutico , Receptores de Orexina/uso terapêutico , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Compostos de Anilina/farmacologia , Benzamidas/farmacologia , Humanos , Estrutura Molecular
9.
PLoS One ; 14(11): e0224938, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31710651

RESUMO

Research efforts directed to elucidation of mechanisms behind trading of resources between the partners in the arbuscular mycorrhizal (AM) symbiosis have seen a considerable progress in the recent years. Yet, despite of the recent developments, some key questions still remain unanswered. For example, it is well established that the strictly biotrophic AM fungus releases phosphorus to- and receives carbon molecules from the plant symbiont, but the particular genes, and their products, responsible for facilitating this exchange, are still not fully described, nor are the principles and pathways of their regulation. Here, we made a de novo quest for genes involved in carbon transfer from the plant to the fungus using genome-wide gene expression array targeting whole root and whole shoot gene expression profiles of mycorrhizal and non-mycorrhizal Medicago truncatula plants grown in a glasshouse. Using physiological intervention of heavy shading (90% incoming light removed) and the correlation of expression levels of MtPT4, the mycorrhiza-inducible phosphate transporter operating at the symbiotic interface between the root cortical cells and the AM fungus, and our candidate genes, we demonstrate that several novel genes may be involved in resource tradings in the AM symbiosis established by M. truncatula. These include glucose-6-phosphate/phosphate translocator, polyol/monosaccharide transporter, DUR3-like, nucleotide-diphospho-sugar transferase or a putative membrane transporter. Besides, we also examined the expression of other M. truncatula phosphate transporters (MtPT1-3, MtPT5-6) to gain further insights in the balance between the "direct" and the "mycorrhizal" phosphate uptake pathways upon colonization of roots by the AM fungus, as affected by short-term carbon/energy deprivation. In addition, the role of the novel candidate genes in plant cell metabolism is discussed based on available literature.


Assuntos
Carbono/metabolismo , Medicago truncatula/microbiologia , Micorrizas/fisiologia , Fósforo/metabolismo , Proteínas de Plantas/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Medicago truncatula/genética , Medicago truncatula/metabolismo , Redes e Vias Metabólicas , Micorrizas/genética , Simbiose , Sequenciamento do Exoma
10.
Med Res Rev ; 39(3): 961-975, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30426515

RESUMO

Narcolepsy is a rare, chronic neurological disease characterized by excessive daytime sleepiness, cataplexy, vivid hallucinations, and sleep paralysis. Narcolepsy occurs in approximately 1 of 3000 people, affecting mainly adolescents aged 15 to 30 years. Recently, people with narcolepsy were shown to exhibit extensive orexin/hypocretin neuronal loss. The orexin system regulates sleep/wake control via complex interactions with monoaminergic, cholinergic and GABA-ergic neuronal systems. Currently, no cure for narcolepsy exists, but some symptoms can be controlled with medication (eg, stimulants, antidepressants, etc). Orexin supplementation represents a more sophisticated way to treat narcolepsy because it addresses the underlying cause of the disease and not just the symptoms. Research on orexin supplementation in the treatment of sleep disorders has strongly increased over the past two decades. This review focuses on a brief description of narcolepsy, the mechanisms by which the orexin system regulates sleep/wake cycles, and finally, possible therapeutic options based on orexin supplementation in animal models and patients with narcolepsy.


Assuntos
Narcolepsia/tratamento farmacológico , Orexinas/uso terapêutico , Animais , Transplante de Células , Terapia Genética , Humanos , Narcolepsia/genética , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
11.
Molecules ; 23(11)2018 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-30423961

RESUMO

The neuropeptides, orexin A and orexin B (also known as hypocretins), are produced in hypothalamic neurons and belong to ligands for orphan G protein-coupled receptors. Generally, the primary role of orexins is to act as excitatory neurotransmitters and regulate the sleep process. Lack of orexins may lead to sleep disorder narcolepsy in mice, dogs, and humans. Narcolepsy is a neurological disorder of alertness characterized by a decrease of ability to manage sleep-wake cycles, excessive daytime sleepiness, and other symptoms, such as cataplexy, vivid hallucinations, and paralysis. Thus, the discovery of orexin receptors, modulators, and their causal implication in narcolepsy is the most important advance in sleep-research. The presented work is focused on the evaluation of compounds L1⁻L11 selected by structure-based virtual screening for their ability to modulate orexin receptor type 2 (OX2R) in comparison with standard agonist orexin-A together with their blood-brain barrier permeability and cytotoxicity. We can conclude that the studied compounds possess an affinity towards the OX2R. However, the compounds do not have intrinsic activity and act as the antagonists of this receptor. It was shown that L4 was the most potent antagonistic ligand to orexin A and displayed an IC50 of 2.2 µM, offering some promise mainly for the treatment of insomnia.


Assuntos
Simulação por Computador , Desenho de Fármacos , Modelos Moleculares , Antagonistas dos Receptores de Orexina/química , Receptores de Orexina/química , Orexinas/química , Animais , Sítios de Ligação , Células CHO , Cricetulus , Concentração Inibidora 50 , Ligantes , Conformação Molecular , Estrutura Molecular , Antagonistas dos Receptores de Orexina/farmacologia , Orexinas/farmacologia , Ligação Proteica , Relação Quantitativa Estrutura-Atividade
12.
Biotechnol Bioeng ; 22(10): 2013-2029, 1980 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29345758

RESUMO

Continuous deacetylation of cephalosporin C, 7-aminocephalosporanic acid, and of 2-methoxyethyl acetate in packed beds of an immobilized esterase is described by simple empirical equations relating conversion to space velocity and temperature. The choice of process conditions is discussed in relation to the effects of temperature on column efficiency, column life, growth of microbial contaminants, and the rates of thermal decomposition of the substrates. At the preferred temperature of 10°C columns were operated continuously for one month with only small losses in efficiency.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...