Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Pestic Biochem Physiol ; 199: 105767, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38458676

RESUMO

The Bonin Archipelago is a United Nations Educational, Scientific and Cultural Organization's World Natural Heritage Site in Japan with a unique ecosystem; however, the invasive rodents preying on endemic species have been a significant concern. The anticoagulant rodenticide, diphacinone, sprayed by the Ministry of the Environment, has succeeded; however, its repeated use leads to rodenticide resistance. This study evaluated the sensitivity by in vivo pharmacokinetics/pharmacodynamics (PK/PD) analysis and physiologically-based pharmacokinetic modeling to diphacinone in black rats (Rattus rattus) captured on the Bonin Archipelago in February 2022. The Bonin rats exhibited prolonged coagulation time after diphacinone administration. They recovered earlier than susceptible black rats, indicating that Bonin rats were less susceptible, though there were no genetic mutations in Vkorc1, the target enzyme of diphacinone. After the administration of diphacinone, hepatic expression levels of Fsp1, identified as the vitamin K reductase, was decreased, however, the Bonin rats exhibited the most minor suppression. The PK analysis showed that the excretion capacity of the Bonin rats was lower than that of the resistant black rats. In the PBPK modeling, the resistant black rats showed higher clearance than the Bonin and susceptible black rats due to high hepatic metabolic capacity. The Bonin rats demonstrated slow absorption and relatively low clearance. This study highlighted the reduced rodenticide-sensitive tendency of wild black rats in the Bonin Archipelago at an in vivo phenotype level. At the same time, they do not have known rodenticide resistance mechanisms, such as hepatic metabolic enhancement or Vkorc1 mutations. It is crucial to monitor the biological levels to evaluate rodenticide sensitivity accurately.


Assuntos
Fenindiona/análogos & derivados , Rodenticidas , Ratos , Animais , Rodenticidas/farmacologia , Japão , Ecossistema
2.
Langmuir ; 40(10): 5338-5347, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38407060

RESUMO

Herein, a low-cost and readily available sodium aluminate (NaAlO2) was used as a solid base catalyst for the depolymerization of polycarbonate (PC) via methanolysis in the presence of tetrahydrofuran (THF) as a solvent. NaAlO2 was highly active for the reaction, and the performance was comparable to that of soluble strong base SrO and much higher than those of MgO and CaO. By the reaction over the catalyst, a highly pure and crystalline bisphenol A (BPA) was obtained. Among tested organic solvents, THF was the best in aiding PC methanolysis over NaAlO2 due to the polarity similar to PC according to Hansen solubility parameters (HSPs). At 60 °C, 98.1% PC conversion and 96.8% BPA yield were achieved within just 2 h. NaAlO2 was reusable without any severe catalyst deactivation in at least four runs. The mechanistic study revealed that the reaction proceeded via the methoxide pathway, with THF aiding the dissolution of PC. The reaction over NaAlO2 possessed a low apparent activation energy (Ea) of 75.1 kJ mol-1, which is the lowest ever reported so far for the reaction over solid catalysts.

3.
Chemistry ; 29(56): e202301917, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37474450

RESUMO

Seven-exo-dig hydrocarboxylation of nonactivated internal alkynes with conformationally flexible linker chains was achieved with cooperative gold-zinc catalysts composed of an imidazo[1,5-a]pyridinylidene ligand including a bipyridine coordination site at the C5 position. A proximity effect of the gold and zinc sites was essential for their high catalytic activity, in which the internal alkyne activated by the cationic gold species was attacked by the carboxylic acid deprotonated by the basic zinc site. Using a gold(I)-complex with a bulky aromatic N-substituent, 2,6-dibenzhydryl-4-methylphenyl group, for the NHC ligand facilitated seven-membered ring formation while minimizing intermolecular hydrocarboxylation as an undesired side reaction. The reaction mechanism was investigated by quantum chemical calculations.

4.
Procedia Comput Sci ; 207: 343-350, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36275390

RESUMO

Many infection preventing measures have been taken in COVID-19 situation. In particular, the approach called Three Cs avoidance is drawing attention. Three Cs means closed spaces, crowded places, and close-contact settings. This approach is taken in many business scenes regardless of individual situation. Such Three Cs are effective, but it is difficult for humans to always be aware of them. Various detection systems have been proposed to help understanding Three Cs situation. Most of them use cameras, CO2 sensors and so on. However, such system is costly due to introduce new equipment. Therefore, we propose a method for detecting Three Cs using only the existing widely used Wi-Fi equipment. Our method introduces unique detection parameters and performs statistical evaluation. As a result of constructing the system and evaluating it, we confirmed that it was possible to detect Three Cs with an accuracy of 86% or more.

6.
Science ; 376(6592): 468, 2022 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-35482861
7.
Science ; 369(6506): 970-974, 2020 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-32820123

RESUMO

Site selectivity and stereocontrol remain major challenges in C-H bond functionalization chemistry, especially in linear aliphatic saturated hydrocarbon scaffolds. We report the highly enantioselective and site-selective catalytic borylation of remote C(sp3)-H bonds γ to the carbonyl group in aliphatic secondary and tertiary amides and esters. A chiral C-H activation catalyst was modularly assembled from an iridium center, a chiral monophosphite ligand, an achiral urea-pyridine receptor ligand, and pinacolatoboryl groups. Quantum chemical calculations support an enzyme-like structural cavity formed by the catalyst components, which bind the substrate through multiple noncovalent interactions. Versatile synthetic utility of the enantioenriched γ-borylcarboxylic acid derivatives was demonstrated.

8.
Food Chem ; 327: 127077, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485660

RESUMO

Compositional analyses of eggs have primarily focused on nutritional components, including large molecules, such as proteins. However, few reports have investigated the effects of heating and hen feed crops on taste components, such as free amino acids and sugars. Herein, water-soluble metabolites in raw and boiled eggs produced from chickens raised with corn- or rice-fed were analyzed. Each egg was separated into yolk and white, and freeze-dried samples were analyzed by CE-MS and LC-MS. Abundant metabolites included amino acids in yolks and sugars in whites. Compared to corn-fed, rice-fed resulted in three times higher betaine and uridine monophosphate concentrations in yolks and whites, respectively. Boiled whites contained more than four times higher concentrations of amino acids and fructose than raw whites. Metabolites in yolks exhibited minimal changes after boiling. Our findings support the use of water-soluble metabolomics to evaluate the effects of heating and feed crops on taste components.


Assuntos
Produtos Agrícolas , Clara de Ovo , Gema de Ovo/metabolismo , Oryza , Zea mays , Ração Animal , Animais , Galinhas , Culinária , Clara de Ovo/química , Gema de Ovo/química , Metaboloma
9.
J Am Chem Soc ; 142(1): 589-597, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31820960

RESUMO

α-Aminoboronic acids, isostructural boron analogues of α-amino acids, have received much attention because of the important biomedical applications implicated for compounds containing this structure. Additionally, the inherent versatility of α-aminoboronic acids as synthetic intermediates through diverse carbon-boron bond transformations makes the efficient synthesis of these compounds highly desirable. Here, we present a Rh-monophosphite chiral catalytic system that enables a highly efficient enantioselective borylation of N-adjacent C(sp3)-H bonds for a range of substrate classes including 2-(N-alkylamino)heteroaryls and N-alkanoyl- or aroyl-based secondary or tertiary amides, some of which are pharmaceutical agents or related compounds. Various stereospecific transformations of the enantioenriched α-aminoboronates, including Suzuki-Miyaura coupling with aryl halides and the Rh-catalyzed reaction with an isocyanate derivative of α-amino acid, affording a new peptide chain elongation method, have been demonstrated. As a highlight of this work, the borylation protocol was successfully applied to the catalyst-controlled site-selective and stereoselective C(sp3)-H borylation of an unprotected dipeptidic compound, allowing remarkably streamlined synthesis of the anti-cancer drug molecule bortezomib and offering a straightforward route for the synthesis of privileged molecular architectures.

10.
Nat Commun ; 6: 6095, 2015 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-25648767

RESUMO

Plant hormones are transported across cell membranes during various physiological events. Recent identification of abscisic acid and strigolactone transporters suggests that transport of various plant hormones across membranes does not occur by simple diffusion but requires transporter proteins that are strictly regulated during development. Here, we report that a major glucosinolate transporter, GTR1/NPF2.10, is multifunctional and may be involved in hormone transport in Arabidopsis thaliana. When heterologously expressed in oocytes, GTR1 transports jasmonoyl-isoleucine and gibberellin in addition to glucosinolates. gtr1 mutants are severely impaired in filament elongation and anther dehiscence resulting in reduced fertility, but these phenotypes can be rescued by gibberellin treatment. These results suggest that GTR1 may be a multifunctional transporter for the structurally distinct compounds glucosinolates, jasmonoyl-isoleucine and gibberellin, and may positively regulate stamen development by mediating gibberellin supply.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Ciclopentanos/metabolismo , Flores/metabolismo , Giberelinas/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Oxilipinas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Transporte de Monossacarídeos/genética
11.
Nat Commun ; 5: 3978, 2014 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-24865297

RESUMO

The colonization of land by plants was a key event in the evolution of life. Here we report the draft genome sequence of the filamentous terrestrial alga Klebsormidium flaccidum (Division Charophyta, Order Klebsormidiales) to elucidate the early transition step from aquatic algae to land plants. Comparison of the genome sequence with that of other algae and land plants demonstrate that K. flaccidum acquired many genes specific to land plants. We demonstrate that K. flaccidum indeed produces several plant hormones and homologues of some of the signalling intermediates required for hormone actions in higher plants. The K. flaccidum genome also encodes a primitive system to protect against the harmful effects of high-intensity light. The presence of these plant-related systems in K. flaccidum suggests that, during evolution, this alga acquired the fundamental machinery required for adaptation to terrestrial environments.


Assuntos
Adaptação Fisiológica/genética , Genoma de Planta , Estreptófitas/genética , Clorofila/metabolismo , Transporte de Elétrons , Fluorescência , Genes de Plantas , Espectrometria de Massas , Microscopia de Interferência , Dados de Sequência Molecular , Família Multigênica , Filogenia , Reguladores de Crescimento de Plantas/metabolismo , Estrutura Terciária de Proteína , Análise de Sequência de DNA , Transdução de Sinais
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...