Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.146
Filtrar
1.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-34707003

RESUMO

OBJECTIVES: To study the inhibitory effects of 1,3-diaminopropane on the biofilm formation of Pseudomonas aeruginosa and the underlying mechanisms. METHODS: The experiment was divided into an experimental group and a control group. Crystal violet staining was used to examine the inhibitory effects of 1,3-diaminopropane on the biofilm formation of Pseudomonas aeruginosa, and the biofilm formation was compared between the 2 groups.Initial adherence inhibition assay and swimming plate assay were used to determine the inhibitory effects of 1,3-diaminopropane on the initial adherence and swimming motility of Pseudomonas aeruginosa,and the quantification of adhered cells and swimming diameter were compared between the 2 groups. Meanwhile, Western blotting was used to detect the Flagellin production of Pseudomonas aeruginosa; real-time RT-PCR was used to detect the quorum sensing system relative genes and flagellum regulative related genes expression in the 2 groups. Finally, molecular docking assay was used to calculate the interaction between 1,3-diaminopropane and LasI. RESULTS: Compared with the control group, the biofilm formation of Pseudomonas aeruginosa was significantly inhibited in the experimental group in a dose-dependent manner (t=6.07, P<0.01).Compared with the control group, the initial adherence of Pseudomonas aeruginosa could significantly inhibit from (0.890±0.389)×106 to (0.245±0.076)×106 CFU/mL (t=3.257, P<0.05) in the experimental group (2.0 mmol/L).Compared with the control group, the swimming motility of Pseudomonas aeruginosa flagellar mediation could also inhibit in the experimental group (2.0 mmol/L). The swimming motility diameter was from (1.840±0.144) to (0.756±0.222) cm (t=7.099, P<0.01). Compared with the control group, the Flagellin production was inhibited in the experimental group. Finally, the molecular docking assay showed that the potential target of 1,3-diaminopropane was LasI. CONCLUSIONS: 1,3-diaminopropane can significantly inhibit the biofilm formation of Pseudomonas aeruginosa, which potentially targets LasI protein.


Assuntos
Pseudomonas aeruginosa , Percepção de Quorum , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Biofilmes , Diaminas , Simulação de Acoplamento Molecular
2.
Mol Biol Rep ; 48(11): 7243-7249, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34613565

RESUMO

BACKGROUND: The new SARS-CoV-2 variant VOC (202012/01), identified recently in the United Kingdom (UK), exhibits a higher transmissibility rate compared to other variants, and a reproductive number 0.4 higher. In the UK, scientists were able to identify the increase of this new variant through the rise of false negative results for the spike (S) target using a three-target RT-PCR assay (TaqPath kit). METHODS: To control and study the current coronavirus pandemic, it is important to develop a rapid and low-cost molecular test to identify the aforementioned variant. In this work, we designed primer sets specific to the VOC (202012/01) to be used by SYBR Green-based RT-PCR. These primers were specifically designed to confirm the deletion mutations Δ69/Δ70 in the spike and the Δ106/Δ107/Δ108 in the NSP6 gene. We studied 20 samples from positive patients, detected by using the Applied Biosystems TaqPath RT-PCR COVID-19 kit (Thermo Fisher Scientific, Waltham, USA) that included the ORF1ab, S, and N gene targets. 16 samples displayed an S-negative profile (negative for S target and positive for N and ORF1ab targets) and four samples with S, N and ORF1ab positive profile. RESULTS: Our results emphasized that all S-negative samples harbored the mutations Δ69/Δ70 and Δ106/Δ107/Δ108. This protocol could be used as a second test to confirm the diagnosis in patients who were already positive to COVID-19 but showed false negative results for S-gene. CONCLUSIONS: This technique may allow to identify patients carrying the VOC (202012/01) or a closely related variant, in case of shortage in sequencing.


Assuntos
Benzotiazóis , COVID-19/virologia , Diaminas , Corantes Fluorescentes , Quinolinas , Reação em Cadeia da Polimerase em Tempo Real/métodos , SARS-CoV-2/isolamento & purificação , COVID-19/diagnóstico , Custos e Análise de Custo , Primers do DNA , Genoma Viral , Humanos , Mutação , Reação em Cadeia da Polimerase em Tempo Real/economia , SARS-CoV-2/genética , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus/genética , Fatores de Tempo
3.
J Virol Methods ; 298: 114294, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34547343

RESUMO

Feline coronavirus (FCoV) contains two serotypes, feline enteric coronavirus (FECV) and Feline infectious peritonitis virus (FIPV). FECV and feline parvovirus (FPV) can cause similar clinical symptoms in cats, such as diarrhea. The objective of this study was to establish a duplex SYBR Green I-based quantitative polymerase chain reaction (qPCR) assay for rapid and simultaneous detection of FPV and FCoV. Two pairs of specific PCR primers were designed to target fragments of the VP2 gene of FPV and of the 5' UTR gene of FCoV, respectively. The assay distinguished between the two viruses based on the melting curves (melting temperatures 77.0 ± 0.5 °C [FPV] and 80.5 ± 0.5 °C [FCoV]). The minimum limits of FPV and FCoV detection were 4.74 × 101 copies/µL and 7.77 × 101 copies/µL, respectively. The assay showed excellent reproducibility and reliability, based on the mean coefficient of variation. In conclusion, this novel duplex SYBR Green I-based qPCR assay is sensitive and can specifically, reliably, and rapidly detect FPV and FCoV (co-)infections.


Assuntos
Coronavirus Felino , Peritonite Infecciosa Felina , Animais , Benzotiazóis , Gatos , Coronavirus Felino/genética , Diaminas , Vírus da Panleucopenia Felina , Quinolinas , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes
4.
J Org Chem ; 86(18): 12932-12944, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34482692

RESUMO

Although dynamic reactions of imines have been extensively studied, the dynamic behaviors manipulated by chirality remain nearly unexplored. In this work, enantioselective amine exchange reactions were demonstrated as a first example via the reaction of enantiomeric chiral amines such as natural amino acids with a series of innovative axially chiral 1,1'-binaphthyl-2,2'-diamine (BNDA)-based imines that were prepared from the condensation reactions between BNDA and salicylaldehyde (SA) or its derivatives. This enantioselective dynamic behavior can be directly indicated by the degree of the fluorescence response of the R-configuration of imines to the d-enantiomer of chiral amine, because the released BNDA can serve as the fluorescence signal output when the amine exchange reaction occurs, which is far higher than the response to its l-enantiomer under identical experimental conditions. For the S-configuration of chiral imines, the fluorescence response is the opposite. The enantioselective exchange reaction can be tuned by altering the electron-withdrawing or electron-donating capability of the substituent at position 4 or 5 of the SA part of chiral imines. Not only o-OH groups in SA-based imines but also protic solvents used as reaction media were found to be important to the dynamic behavior at high rates.


Assuntos
Aminas , Iminas , Catálise , Diaminas , Estereoisomerismo
5.
Biomolecules ; 11(7)2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-34356678

RESUMO

Allograft kidney transplantation, which triggers host cellular- and antibody-mediated rejection of the kidney, is a major contributor to kidney damage during transplant. Here, we asked whether PrC-210 would suppress damage seen in allograft kidney transplant. Brown Norway (BN) rat kidneys were perfused in situ (UW Solution) with or without added 30 mM PrC-210, and then immediately transplanted into Lewis (LEW) rats. 20 h later, the transplanted BN kidneys and LEW rat plasma were analyzed. Kidney histology, and kidney/serum levels of several inflammation-associated cytokines, were measured to assess mismatch-related kidney pathology, and PrC-210 protective efficacy. Twenty hours after the allograft transplants: (i) significant histologic kidney tubule damage and mononuclear inflammatory cell infiltration were seen in allograft kidneys; (ii) kidney function metrics (creatinine and BUN) were significantly elevated; (iii) significant changes in key cytokines, i.e., TIMP-1, TNF-alpha and MIP-3A/CCL20, and kidney activated caspase levels were seen. In PrC-210-treated kidneys and recipient rats, (i) kidney histologic damage (Banff Scores) and mononuclear infiltration were reduced to untreated background levels; (ii) creatinine and BUN were significantly reduced; and (iii) activated caspase and cytokine changes were significantly reduced, some to background. In conclusion, the results suggest that PrC-210 could provide broadly applicable organ protection for many allograft transplantation conditions; it could protect transplanted kidneys during and after all stages of the transplantation process-from organ donation, through transportation, re-implantation and the post-operative inflammation-to minimize acute and chronic rejection.


Assuntos
Diaminas/farmacologia , Inflamação/tratamento farmacológico , Transplante de Rim/efeitos adversos , Rim/efeitos dos fármacos , Compostos de Sulfidrila/farmacologia , Adenosina , Aloenxertos , Alopurinol , Animais , Caspases/metabolismo , Creatinina/sangue , Citocinas/metabolismo , Diaminas/administração & dosagem , Sequestradores de Radicais Livres/farmacologia , Glutationa , Inflamação/patologia , Insulina , Rim/patologia , Transplante de Rim/métodos , Masculino , Mitocôndrias/efeitos dos fármacos , Soluções para Preservação de Órgãos , Rafinose , Ratos Endogâmicos BN , Ratos Endogâmicos Lew , Compostos de Sulfidrila/administração & dosagem
6.
Microbes Environ ; 36(3)2021.
Artigo em Inglês | MEDLINE | ID: mdl-34433737

RESUMO

Microbial cell counting provides essential information for the study of cell abundance profiles and biogeochemical interactions with the surrounding environments. However, it often requires labor-intensive and time-consuming processes, particularly for subseafloor sediment samples, in which non-cell particles are abundant. We developed a rapid and straightforward method for staining microbial intracellular DNA by SYBR Green I (SYBR-I) to enumerate cells by flow cytometry (FCM). We initially examined the efficiency of microbial cell staining at various dye/sediment ratios (volume ratio of SYBR-I/sediment [vSYBR/vSed]). Non-cell particles in sediment strongly and preferentially adsorbed SYBR-I dye, resulting in the unsuccessful staining of microbial cells when an insufficient ratio (<1.63 vSYBR/vSed) of SYBR-I dye was present per volume of sediment. SYBR-I dye at an abundance of 10 vSYBR/vSed successfully and stably stained microbial cells in green fluorescence, while the fluorescent color of non-cell particles red-shifted to yellow-orange with the overaccumulation of SYBR-I dye. A low vSYBR/vSed ratio was quickly recognized by a colorless supernatant after centrifugation. At the appropriate vSYBR/vSed ratio, FCM-measured cell concentrations in subseafloor sediments were consistently similar to microscopy counts (>106 cells cm-3). Samples with low cell abundance (<105 cells cm-3) still require cell separation. This modified staining allows us to efficiently process and perform the microbial cell counting of sediment samples to a depth of a few hundred meters below the seafloor with a higher throughput and capability to scale up than procedures employing microscopy-based observations.


Assuntos
Bactérias/química , Bactérias/citologia , Sedimentos Geológicos/microbiologia , Coloração e Rotulagem/métodos , Benzotiazóis/química , DNA Bacteriano/química , Diaminas/química , Citometria de Fluxo , Fluorescência , Corantes Fluorescentes/química , Quinolinas/química , Água do Mar/microbiologia
7.
Avian Dis ; 65(2): 281-286, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34412459

RESUMO

Duck viral hepatitis (DVH) mainly affects ducklings under 1 month of age, causes liver necrosis, enlargement, and hemorrhage, and is highly lethal, seriously jeopardizing the duck industry. The prevalence of duck hepatitis A virus (DHAV-1) and duck astrovirus type 3 (DAstV-3) is increasing, and coinfection is common. Moreover, the similar clinical characteristics of the DHAV-1 and DAstV-3 infections and the high frequency of coinfection make diagnosis difficult. In this study, to establish a method for the rapid, simultaneous detection of DHAV-1 and DAstV-3, two pairs of specific primers were designed according to their conserved gene regions. An SYBR® Green I-based qPCR assay was successfully established that can quickly and differentially detect the two viruses. Moreover, the assay is highly specific and does not show cross-reaction with other common viruses. The detection limit of the method is 7.34 × 101 copies/µl and 3.78 × 101 copies/µl for DHAV-1 and DAstV-3, respectively, indicating high sensitivity. A total of 34 clinical samples were tested using the established method; the positive rates for DHAV-1 and DAstV-3 were 14.71% and 8.82%, respectively, and that for coinfection was 2.94% (1/34), which was better than that obtained with conventional PCR. In summary, the SYBR Green I-based qPCR assay established in this study has high specificity, good sensitivity and accuracy, high feasibility, and is rapid. Thus, it can be a powerful tool for the coinfection detection of DHAV-1 and DAstV-3 and for future epidemiologic studies.


Assuntos
Infecções por Astroviridae/veterinária , Avastrovirus/isolamento & purificação , Vírus da Hepatite do Pato/isolamento & purificação , Hepatite Viral Animal/diagnóstico , Infecções por Picornaviridae/veterinária , Animais , Infecções por Astroviridae/complicações , Infecções por Astroviridae/diagnóstico , Infecções por Astroviridae/epidemiologia , Avastrovirus/genética , Benzotiazóis , Diagnóstico Diferencial , Diaminas , Estudos de Viabilidade , Corantes Fluorescentes , Vírus da Hepatite do Pato/genética , Hepatite Viral Animal/complicações , Hepatite Viral Animal/epidemiologia , Infecções por Picornaviridae/complicações , Infecções por Picornaviridae/diagnóstico , Infecções por Picornaviridae/epidemiologia , Quinolinas , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores de Tempo
8.
Biomed Pharmacother ; 139: 111611, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34243597

RESUMO

Trichomonas vaginalis is an amitochondriate protozoan and the agent of human trichomoniasis, the most prevalent non-viral sexually transmitted infection (STI) in the world. In this study we showed that 2,4-diamine-quinazoline derivative compound (PH100) kills T. vaginalis. PH100 showed activity against fresh clinical and American Type Culture Collection (ATCC) T. vaginalis isolates with no cytotoxicity against cells (HMVI, 3T3-C1 and VERO) and erythrocytes. In addition, PH100 showed synergistic action with metronidazole, indicating that these compounds act by different mechanisms. When investigating the mechanism of action of PH100 to ATCC 30236, apoptosis-like characteristics were observed, such as phosphatidylserine exposure, membrane alterations, and modulation of gene expression and activity of peptidases related to apoptosis. The apoptosis-like cell death features were not observed for the fresh clinical isolate treated with PH100 revealing distinct profiles. Our data revealed the heterogeneity among T. vaginalis isolates and contribute with the understanding of mechanisms of cell death in pathogenic eukaryotic organisms without mitochondria.


Assuntos
Diaminas/farmacologia , Parasitos/efeitos dos fármacos , Peptídeo Hidrolases/metabolismo , Quinazolinas/farmacologia , Vaginite por Trichomonas/tratamento farmacológico , Trichomonas vaginalis/efeitos dos fármacos , Células 3T3 , Animais , Apoptose/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular , Chlorocebus aethiops , Feminino , Humanos , Metronidazol/farmacologia , Camundongos , Vaginite por Trichomonas/parasitologia , Células Vero
9.
J Org Chem ; 86(15): 10654-10664, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34314190

RESUMO

Novel 1,2-diamines based on the mefloquine scaffold prepared in enantiomerically pure forms resemble 9-amino-Cinchona alkaloids. Most effectively, 11-aminomefloquine with an erythro configuration was obtained by conversion of 11-alcohol into azide and hydrogenation. Alkylation of a secondary amine unit was needed to arrive at diastereomeric threo-11-aminomefloquine and to introduce diversity. Most of the substitution reactions of the hydroxyl group to azido group proceeded with net retention of the configuration and involved actual aziridine or plausible aziridinium ion intermediates. Enantiomerically pure products were obtained by the resolution of either the initial mefloquine or one of the final products. The evaluation of the efficacy of the obtained vicinal diamines in enantioselective transformations proved that erythro-11-aminomefloquine is an effective catalyst in the asymmetric Michael addition of nitromethane to cyclohexanone (up to 96.5:3.5 er) surpassing epi-aminoquinine in terms of selectivity.


Assuntos
Diaminas , Mefloquina , Aminas , Estrutura Molecular , Estereoisomerismo
10.
Eur J Med Chem ; 224: 113672, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34237620

RESUMO

Combination of anaplastic lymphoma kinase (ALK) inhibitor with histone deacetylases (HDAC) inhibitor could exert synergistically anti-proliferative effects on ALK positive non-small cell lung cancer (NSCLC) naïve or resistant cells. In this work, we designed and synthesized a series of 2,4-pyrimidinediamine derivatives as dual ALK and HDAC inhibitors based on pharmacophore merged strategy. Among which, compound 10f displayed the most potent and balanced inhibitory activity against ALK (IC50 = 2.1 nM) and HDAC1 (IC50 = 7.9 nM), respectively. In particular, 10f was also potent against the frequently observed Crizotinib-resistant ALKL1196M (IC50 = 1.7 nM) as well as the Ceritinib-resistant ALKG1202R (IC50 = 0.4 nM) mutants. In antiproliferative activity assay, 10f exhibited impressive activity on ALK-addicted cancer cell lines at low micromole concentrations, which was comparable to that of Crizotinib and Ceritinib. Further flow cytometric analysis indicated that 10f could effectively induce cell death via cell apoptosis and cell cycle arrest. Taken together, these results suggested 10f would be a promising lead compound for the ALK-positive NSCLC treatment, especially the Ceritinib- or Crizotinib-resistant NSCLC.


Assuntos
Quinase do Linfoma Anaplásico/antagonistas & inibidores , Diaminas/química , Inibidores de Histona Desacetilases/química , Histona Desacetilases/química , Inibidores de Proteínas Quinases/química , Quinase do Linfoma Anaplásico/metabolismo , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Sítios de Ligação , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Diaminas/metabolismo , Diaminas/farmacologia , Desenho de Fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores de Histona Desacetilases/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Humanos , Simulação de Dinâmica Molecular , Inibidores de Proteínas Quinases/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/química , Relação Estrutura-Atividade
11.
Vet Parasitol ; 296: 109496, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34147018

RESUMO

Gastrointestinal nematodes (GIN) infections are a serious problem in livestock production due to the great economic losses they cause. Their control is increasingly difficult because of the rapid development of drug resistance and the limited number of available drugs. Therefore, this study evaluated 18 aminoalcohol and 16 diamine derivatives against eggs, first and third stage larvae from a susceptible and a resistant isolate of Teladorsagia circumcincta collected from sheep. The effectiveness of the in vitro anthelmintic activity of the compounds was evaluated using three different procedures: Egg Hatch Test (EHT), Larval Mortality Test (LMT) and Larval Migration Inhibition Test (LMIT). Those compounds with activities higher than 90 % in the initial screening at 50 µM were selected to determine their half maximal effective concentration (EC50). In parallel, cytotoxicity assays were conducted on Caco2 and HepG2 cell lines to calculate Selectivity Indexes (SI) for each compound. The diamine 30 presented the best results in preventing egg hatching, displaying the lowest EC50 value (1.01 ±â€¯0.04 µM) of all compounds tested and the highest SI (21.21 vs. Caco-2 cells). For the LMIT, the diamine 34 showed the highest efficacy, with EC50 values of 2.67 ±â€¯0.08 and 3.02 ±â€¯0.09 µM on the susceptible and resistant isolate of the parasite, respectively.


Assuntos
Álcoois , Anti-Helmínticos , Diaminas , Nematoides , Doenças dos Ovinos , Álcoois/farmacologia , Álcoois/uso terapêutico , Animais , Anti-Helmínticos/farmacologia , Anti-Helmínticos/uso terapêutico , Células CACO-2 , Diaminas/farmacologia , Diaminas/uso terapêutico , Resistência a Medicamentos/efeitos dos fármacos , Fezes , Humanos , Óvulo/efeitos dos fármacos , Ovinos , Doenças dos Ovinos/tratamento farmacológico
12.
Int J Mol Sci ; 22(10)2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34069142

RESUMO

Bone healing is a complex, well-organized process. Multiple factors regulate this process, including growth factors, hormones, cytokines, mechanical stimulation, and aging. One of the most important signaling pathways that affect bone healing is the Notch signaling pathway. It has a significant role in controlling the differentiation of bone mesenchymal stem cells and forming new bone. Interventions to enhance the healing of critical-sized bone defects are of great importance, and stem cell transplantations are eminent candidates for treating such defects. Understanding how Notch signaling impacts pluripotent stem cell differentiation can significantly enhance osteogenesis and improve the overall healing process upon transplantation. In Rancourt's lab, mouse embryonic stem cells (ESC) have been successfully differentiated to the osteogenic cell lineage. This study investigates the role of Notch signaling inhibition in the osteogenic differentiation of mouse embryonic and induced pluripotent stem cells (iPS). Our data showed that Notch inhibition greatly enhanced the differentiation of both mouse embryonic and induced pluripotent stem cells.


Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Diferenciação Celular/efeitos dos fármacos , Osteogênese/genética , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/efeitos dos fármacos , Animais , Osso e Ossos/metabolismo , Proteínas de Ciclo Celular/genética , Diferenciação Celular/fisiologia , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Dexametasona/farmacologia , Diaminas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/fisiologia , Mesoderma/citologia , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/efeitos dos fármacos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Osteogênese/efeitos dos fármacos , Células-Tronco Pluripotentes/metabolismo , Receptores Notch/metabolismo , Tiazóis/farmacologia , Fatores de Transcrição HES-1/genética , Vitamina D/farmacologia
13.
J Chromatogr A ; 1651: 462278, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34102399

RESUMO

A simple method for the determination of polyamines and their N-acetylated forms was developed using benzoyl chloride as derivatization reagent, and 1,6-diaminohexane as internal standard, followed by liquid-liquid extraction with ethyl acetate. The organic extract was injected in a gas chromatograph using a programmed temperature vaporizer and the determination and quantification was performed with a quadrupole mass spectrometer. There was no matrix effect with the proposed method, so internal calibration was used to quantify the corresponding derivatives. Good linear responses were obtained in the range from the limits of detection to 500 µg L-1 (50 µg L-1 for spermidine), with correlation coefficients varying from 0.9591 to 0.9968. The limits of quantification (S/N = 10) ranged 1.0 - 8.3 µg L-1. Recoveries were found between 82 - 117%, showing the good accuracy of the proposed method. Intra- and inter-day precision assays, expressed as relative standard deviation (RSD) were evaluated at two different concentration levels (low and high), showing values in the range of 2.4 - 6.1% and 5.2 - 9.0% for repeatability and reproducibility, respectively (6.9 - 9.7% and 14.1 - 14.6% for spermidine). Successful determination of the studied polyamines and their N-acetylated forms was performed on the saliva of 17 volunteers.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Poliaminas/análise , Saliva/química , Acetilação , Benzoatos , Diaminas , Humanos , Extração Líquido-Líquido , Poliaminas/química , Reprodutibilidade dos Testes
14.
J Org Chem ; 86(12): 8365-8380, 2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34097406

RESUMO

A new photocatalyst-free visible-light-enhanced strategy for the synthesis of pyrazolo[1,5-a][1,3,5]triazine-2,4-diamines via the formation of electron donor-acceptor (EDA) complexes is reported. The in situ generated pyrazolthiourea intermediates from 1H-pyrazol-3-amines and isothiocyanates undergo formal [4 + 2] annulation with 1,1,3,3-tetramethylguanidines (TMG) to deliver the corresponding products involved in three C-N bond formations in a one-pot protocol. The formation of EDA complex from pyrazolthiourea and TMG is confirmed by UV-vis spectroscopy and 1H NMR experiments. Moreover, this mild reaction proceeds in the absence of any external transition metals, oxidants, bases, and ligands. This efficient methodology for the synthesis of purine analogues pyrazolo[1,5-a][1,3,5]triazine-2,4-diamines provides potential synthetic applications in the field of drug research and development.


Assuntos
Diaminas , Triazinas , Aminas , Luz , Purinas
15.
Luminescence ; 36(7): 1632-1637, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34137155

RESUMO

Lipopolysaccharides (endotoxins), found on Gram-negative bacteria, can trigger a severe immune response in humans leading to septic shock and in extreme cases, even death. Therefore, the detection and neutralization of lipopolysaccharides (LPS) is of utmost importance in the pharmaceutical and medical industries. The United States Food and Drug Administration (US FDA) recommended detection method for LPS, the Limulus amebocyte lysate (LAL) assay, is expensive, time consuming, complex, and is prone to interference from proteases. As an alternative, this paper proposes a rapid, label-free fluorescence-based assay using LPS-specific aptamers and the SYBR Green DNA stain. The proposed method has a detection limit of 0.1 ng/ml, which is sufficient to detect the permissible levels of LPS in many pharmaceutical drugs and medical products. The fluorescence signal was found to be a linear function of the concentration of LPS in the range from 0.1 ng/ml to 105 ng/ml.


Assuntos
Endotoxinas , Lipopolissacarídeos , Benzotiazóis , Bioensaio , Diaminas , Humanos , Oligonucleotídeos , Quinolinas , Estados Unidos
16.
Nature ; 596(7871): 250-256, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34182570

RESUMO

The substitution of an alkyl electrophile by a nucleophile is a foundational reaction in organic chemistry that enables the efficient and convergent synthesis of organic molecules. Although there has been substantial recent progress in exploiting transition-metal catalysis to expand the scope of nucleophilic substitution reactions to include carbon nucleophiles1-4, there has been limited progress in corresponding reactions with nitrogen nucleophiles5-8. For many substitution reactions, the bond construction itself is not the only challenge, as there is a need to control stereochemistry at the same time. Here we describe a method for the enantioconvergent substitution of unactivated racemic alkyl electrophiles by a ubiquitous nitrogen-containing functional group, an amide. Our method uses a photoinduced catalyst system based on copper, an Earth-abundant metal. This process for asymmetric N-alkylation relies on three distinct ligands-a bisphosphine, a phenoxide and a chiral diamine. The ligands assemble in situ to form two distinct catalysts that act cooperatively: a copper/bisphosphine/phenoxide complex that serves as a photocatalyst, and a chiral copper/diamine complex that catalyses enantioselective C-N bond formation. Our study thus expands enantioselective N-substitution by alkyl electrophiles beyond activated electrophiles (those bearing at least one sp- or sp2-hybridized substituent on the carbon undergoing substitution)8-13 to include unactivated electrophiles.


Assuntos
Amidas/química , Cobre/química , Fotoquímica , Brometos/química , Carbono/química , Catálise , Ciclização , Diaminas/química , Ligantes , Nitrogênio/química , Fosfinas/química
17.
Environ Sci Pollut Res Int ; 28(39): 55655-55666, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34138426

RESUMO

Diatomite (D) as a low-cost and eco-friendly clay was modified by ethylene diamine (EDA)-trimesoyl chloride (TMC) polymer to achieve a novel adsorbent for efficient removal of rhodamine B dye (RB) from wastewater samples. The EDA-TMC polymer was grafted to the surface of diatomite by in situ interfacial polymerization. The prepared p(EDA-TMC)/D adsorbent was characterized by XRD, FTIR, and SEM/EDX techniques. The effective experimental parameters on the adsorption performance were optimized with factorial design analysis. The equilibrium data were better correlated by non-linear Langmuir model compared to non-linear Freundlich model. The Langmuir monolayer adsorption capacity of the p(EDA-TMC)/D adsorbent was determined as 371.8 mg g-1. The key adsorption parameters were optimized by experimental design analysis. The kinetic findings showed the adsorption mechanism of RB onto p(EDA-TMC)/D adsorbent was well designated by the pseudo-second-order kinetic model. The thermodynamic results indicate that the RB adsorption had an exothermic character in thermal nature and was less favorable with increasing temperature from 20 to 60 °C. Furthermore, the adsorption/desorption yield of p(EDA-TMC)/D was still 80%/70% after 5th cycle and reduced to 60%/52% at the end of 8th cycle. Thus, the present study revealed that the developed p(EDA-TMC)/D composite had great adsorption potential for removal of RB from wastewater samples compared to that of different kinds of adsorbents reported in the literature.


Assuntos
Diaminas , Águas Residuárias , Cloretos , Terra de Diatomáceas , Etilenos , Rodaminas
18.
Chem Commun (Camb) ; 57(48): 5941-5944, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34018521

RESUMO

This work describes a single-stranded degradable modular grafting probe for analyzing microRNA-21. In the system, the exonuclease activity of phi29 polymerase restrains the SYBR Green I/ssDNA induced background. The palindrome activation caused remarkable target fluorescence. The detection limit was achieved as 0.26 fM, showing potential in biochemical analysis.


Assuntos
Benzotiazóis/química , DNA de Cadeia Simples/química , Diaminas/química , Exodesoxirribonucleases/química , MicroRNAs/análise , Quinolinas/química , Benzotiazóis/metabolismo , DNA de Cadeia Simples/metabolismo , Diaminas/metabolismo , Exodesoxirribonucleases/metabolismo , Fluorescência , Humanos , MicroRNAs/metabolismo , Técnicas de Amplificação de Ácido Nucleico , Quinolinas/metabolismo
19.
Chem Commun (Camb) ; 57(50): 6153-6156, 2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34042925

RESUMO

We report here the first example of the direct synthesis of polyureas from the dehydrogenative coupling of diamines and methanol using a ruthenium pincer catalyst. The present methodology replaces the use of toxic diisocyanates, conventionally used for the production of polyureas, with methanol, which is renewable, less toxic, and cheaper, making the overall process safer and more sustainable. Further advantages of the current method have been demonstrated by the synthesis of a renewable, a chiral, and the first 13C-labelled polyurea.


Assuntos
Diaminas/química , Metanol/química , Polímeros/síntese química , Catálise , Hidrogenação , Estrutura Molecular , Polímeros/química , Rutênio
20.
Acta Chim Slov ; 68(1): 102-108, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34057515

RESUMO

A mononuclear copper(II) complex, [CuL] (1), and a phenolato-bridged trinuclear zinc(II) complex, [Zn3Cl2L2(DMF)2] (2), where L is the deprotonated form of N,N'-bis(4-bromosalicylidene)propane-1,3-diamine (H2L), have been prepared and characterized by elemental analyses, IR and UV-Vis spectroscopy, and single crystal X-ray diffraction. The Cu atom in complex 1 is in square planar coordination, while the terminal and central Zn atoms in complex 2 are in square pyramidal and octahedral coordination, respectively. The antibacterial activities of the complexes have been tested on the bacteria Staphylococcus aureus and Escherichia coli, and the yeast Candida parapsilosis.


Assuntos
Antibacterianos/farmacologia , Complexos de Coordenação/farmacologia , Diaminas/farmacologia , Fenóis/farmacologia , Antibacterianos/síntese química , Candida parapsilosis/efeitos dos fármacos , Complexos de Coordenação/síntese química , Cobre/química , Cristalografia por Raios X , Diaminas/síntese química , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Fenóis/síntese química , Staphylococcus aureus/efeitos dos fármacos , Zinco/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...