Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.758
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
J Agric Food Chem ; 68(1): 185-192, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31815467

RESUMO

Phytopathogenic fungi have been considered as being an enormous threat in the agricultural system. In our search of new antifungal natural products, nine new halogenated cyclopentenones, bicolorins A-I (1-3, and 5-10), along with three known cyclopentenones (4, 11, and 12) were isolated from the endophytic fungus Saccharicola bicolor of Bergenia purpurascens by the one strain-many compounds strategy. Their structures and absolute configurations were elucidated based on extensive spectroscopic analysis, X-ray crystallographic analysis, and time-dependent density functional theory-equivalent circulating density calculations. Compounds 1-12 showed antifungal activities against five phytopathogenic fungi (Uromyces viciae-fabae, Pythium dissimile, Gibberella zeae, Aspergillus niger, and Sclerotinia sclerotiorum). Especially, bicolorins B and D (2 and 5) exhibited strong antifungal activities against P. dissimile with the MIC values of 6.2 and 8.5 µg/mL, respectively, compared with the positive control cycloheximide (MIC of 8.6 µg/mL). Additionally, bicolorin D was proven to be potently antifungal against S. sclerotiorum in vitro and in vivo. This work provides an effective strategy for searching antifungal candidate agents.


Assuntos
Ascomicetos/química , Ciclopentanos/química , Ciclopentanos/farmacologia , Endófitos/química , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Saxifragaceae/microbiologia , Ascomicetos/isolamento & purificação , Ascomicetos/metabolismo , Ciclopentanos/metabolismo , Endófitos/isolamento & purificação , Endófitos/metabolismo , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Fungicidas Industriais/metabolismo , Halogenação , Estrutura Molecular , Doenças das Plantas/microbiologia
2.
Food Chem ; 309: 125737, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31780227

RESUMO

Chlorophyll degradation is the main reason for postharvest yellowing of broccoli. To uncover the role of jasmonic acid (JA) on the degradation of chlorophyll, broccoli flowers were treated with exogenous methyl jasmonate (MeJA) and diethyldithiocarbamic acid (DIECA). We found a surge of endogenous JA content with the yellowing process, and a significant correlation between JA and chlorophyll content. MeJA treatments led to increased endogenous JA, increased allene oxide cyclase (AOC) activity, and enhanced expression of JA synthesis genes. MeJA caused a stronger reduction in the maximum quantum yield (Fv/Fm), fluorescence decline ratio (Rfd), and total chlorophyll content, advanced the peak of pheide a oxygenase (PAO) activity, and up-regulated the expression of chlorophyll degradation genes. The DIECA treatment resulted in lower endogenous levels of JA, and AOC and 12-oxo-phytodienoic acid reductase (OPR) activity. This study revealed that the potential role of JA on broccoli yellowing is to promote the chlorophyll degradation.


Assuntos
Brassica/metabolismo , Clorofila/metabolismo , Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Acetatos/farmacologia , Brassica/efeitos dos fármacos , Clorofila/química , Ciclopentanos/química , Ciclopentanos/farmacologia , Ditiocarb/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oxirredutases Intramoleculares/metabolismo , Oxigenases/metabolismo , Oxilipinas/química , Oxilipinas/farmacologia
3.
Biomed Khim ; 65(6): 520-525, 2019 Oct.
Artigo em Russo | MEDLINE | ID: mdl-31876523

RESUMO

The overall model for prediction of IC50 values for inhibitors of neuraminidase influenza virus A and B has been created. It combines data about IC50 values of complexes of 40 variants of neuraminidases of influenza A (7 serotypes) and B and three known inhibitors (oseltamivir, zanamivir, peramivir). The model also uses only data of enthalpy contributions to the potential energy of inhibitor/protein and substrate (MUNANA)/protein complexes. The calculation procedures are ported to use software with support of GPU accelerators, that significant decrease the computation time. The corresponding correlation coefficient (R²) for pIC50 prediction was within 0.45-0.58, the SEM values of around 0.7 (the range of used pIC50 data set is from 4.55 to 10.22).


Assuntos
Antivirais/química , Vírus da Influenza A/efeitos dos fármacos , Vírus da Influenza B/efeitos dos fármacos , Neuraminidase/antagonistas & inibidores , Proteínas Virais/antagonistas & inibidores , Ciclopentanos/química , Inibidores Enzimáticos/química , Guanidinas/química , Vírus da Influenza A/enzimologia , Vírus da Influenza B/enzimologia , Oseltamivir/química , Zanamivir/química
4.
J Chem Ecol ; 45(11-12): 1004-1018, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31755020

RESUMO

Latex occurs in 10% of plant families, has evolved independently many times, and is the most effective defense of milkweeds against its chewing herbivores. Here we report on new experiments on the heritability and inducibility of latex in several milkweed species. In addition, we review what is known about the genetic and environmental determinants of latex exudation, hormonal regulation, evolution within and among species, and the role and frequency of latex in agricultural crops. We first evaluated genotype-by-environment interactions using ~20 full-sibling genetic families in each of seven Asclepias species treated as controls or attacked by monarch butterfly caterpillars. All species showed substantial genetic variation for latex exudation and six of seven species responded to monarch herbivory (two species increased latex, two species decreased, and two showed variation among genetic families). Exogenous application of jasmonic acid (JA) to three species induced a consistent increase in latex (including species which showed a decline following caterpillar herbivory). We next evaluated three hypotheses for what determines genetic variation for induced latex in A. syriaca: 1) a trade-off with constitutive investment, 2) differential endogenous JA induction, or 3) variation in responsiveness to JA. We only found support for the second hypothesis: genetic families with a stronger JA-burst showed the greatest latex exudation following herbivory. We conclude that most species exhibit a genetic and inducible basis for latex, although genetic variation in inducibility is not pervasive. Finally, we summarized studies across 22 species of Asclepias and found that neither a species' latitude nor its phylogenetic position predicted latex inducibility. Nonetheless, a negative association between constitutive and induced latex across species indicates a macroevolutionary trade-off in allocation to this defense. Our review indicates that jasmonic acid is a key regulator of latex exudation, laticifer morphology, and defensive metabolites within latex. Biotic and abiotic factors strongly modulate latex expression. A survey of latex in food crops revealed that latex and analogous exudates (gums, resins, mucilage) are more common than expected based on their distribution across all plants. In conclusion, despite its widespread occurrence, the literature on latex is currently dominated by rubber trees and milkweeds, and we look forward to the broadening of ecological, agricultural, and mechanistic research into other systems.


Assuntos
Asclepias/química , Látex/química , Látex/metabolismo , Animais , Borboletas/fisiologia , Produtos Agrícolas , Ciclopentanos/química , Ciclopentanos/metabolismo , Genótipo , Herbivoria , Interações Hospedeiro-Parasita , Larva/metabolismo , Masculino , Oxilipinas/química , Oxilipinas/metabolismo , Filogenia , Folhas de Planta/química , Transdução de Sinais
5.
SAR QSAR Environ Res ; 30(12): 899-917, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31645133

RESUMO

Influenza A virus (IAV) has caused epidemic infections worldwide, with many strains resistant to inhibitors of a surface protein, neuraminidase (NA), due to point mutations on its structure. A novel NA inhibitor named peramivir was recently approved, but no exhaustive computational research regarding its binding affinity with wild-type and mutant NA has been conducted. In this study, a thorough investigation of IAV-NA PDB entries of 9 subtypes is described, providing a list of residues constituting the protein-ligand binding sites. The results of induced-fit docking approach point out key residues of wild-type NA participating in hydrogen bonds and/or ionic interactions with peramivir, among which Arg 368 is responsible for a peramivir-NA ionic interaction. Mutations on this residue greatly reduced the binding affinity of peramivir with NA, with 3 mutations R378Q, R378K and R378L (NA6) capable of deteriorating the docking performance of peramivir by over 50%. 200 compounds from 6-scaffolds were docked into these 3 mutant versions, revealing 18 compounds giving the most promising results. Among them, CMC-2012-7-1527-56 (benzoic acid scaffold, IC50 = 32 nM in inhibitory assays with IAV) is deemed the most potential inhibitor of mutant NA resisting both peramivir and zanamivir, and should be further investigated.


Assuntos
Antivirais/química , Ciclopentanos/química , Inibidores Enzimáticos/química , Guanidinas/química , Neuraminidase/química , Proteínas Virais/química , Sítios de Ligação , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Mutação , Neuraminidase/antagonistas & inibidores , Neuraminidase/genética , Relação Quantitativa Estrutura-Atividade , Proteínas Virais/antagonistas & inibidores , Proteínas Virais/genética
6.
Ecotoxicol Environ Saf ; 185: 109691, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31563746

RESUMO

The rational use and the environmental safety of chiral pesticides have attracted significant research interest. Here, enantioselective toxic effects and the selective toxic mechanism of triticonazole (TRZ) against the aquatic microalgae Chlorella pyrenoidosa were studied. The 96h-EC50 values of rac-, (R)-(-)-, and (S)-(+)-TRZ were 1.939, 0.853, and 22.002 mg/L, respectively. At a concentration of 1 mg/L, the contents of photosynthetic pigments of C. pyrenoidosa exposed to (R)-(-)-TRZ were lower than if exposed to S-(+)-form and racemate. Transmission electron microscopic images showed that the R-(-)-form compromised the integrity of cells and disrupted the chloroplast structure. R-(-)-TRZ stimulated vast reactive oxygen species (ROS) and significantly increased superoxide dismutase (SOD) and catalase (CAT) activities, as well as malondialdehyde (MDA) content. For lipid accumulation experiments, nicotinamide adenine dinucleotide (NADH) and triacylglycerol (TAG) accumulations in algal cells treated with R-(-)-TRZ were 171.50% and 280.76%, respectively, compared with the control group. This far exceeded levels of algal cells treated with S-(+)- and rac-TRZ. Based on these data, R-(-)-TRZ was concluded to selectively affect the photosynthetic system, antioxidant system, and lipid synthesis of algal cells, thus causing enantioselective toxic effects of TRZ against C. pyrenoidosa, which indicating that the use of racemate may cause unpredictable environmental harm. Therefore, to reduce the hidden dangers of chiral pesticides for the ecological environment, the environmental risk of TRZ should be evaluated at the stereoselective level.


Assuntos
Chlorella/efeitos dos fármacos , Ciclopentanos/toxicidade , Fungicidas Industriais/toxicidade , Microalgas/efeitos dos fármacos , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Antioxidantes/metabolismo , Chlorella/metabolismo , Chlorella/ultraestrutura , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Ciclopentanos/química , Fungicidas Industriais/química , Malondialdeído/farmacologia , Microalgas/metabolismo , Microalgas/ultraestrutura , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Estereoisomerismo , Superóxido Dismutase/metabolismo , Triazóis/química , Poluentes Químicos da Água/química
7.
Chem Pharm Bull (Tokyo) ; 67(9): 1019-1022, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31474725

RESUMO

A novel catalyst system-a combination of the readily available 2,2'-biphenol with the inexpensive, nontoxic, and eco-friendly B(OH)3-promoted the Nazarov cyclization of activated and inactivated divinyl ketones to afford the corresponding cyclopentenones up to 96% yield under, in a cis-selective manner. Compared with the conventional harsh conditions with hazardous reagents, user-friendly method was established with bench-stable and easy-to-handle reagents.


Assuntos
Fenóis/química , Ácidos Borônicos/química , Catálise , Ciclização , Ciclopentanos/química
8.
Anticancer Res ; 39(8): 4479-4483, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31366548

RESUMO

BACKGROUND/AIM: The stereo-configuration (R-, S-configuration) of chiral-2-nitroimidazole derivatives alters their radiosensitizing activity. This study aimed at examining the molecular features of these enantiomers by molecular simulation techniques. MATERIALS AND METHODS: A series of 2-nitroimidazole-based radiosensitizer TX-2036 molecules were synthesized, and their profiles were examined using molecular structural analysis such as conformation analysis, molecular orbital analysis, and electrostatic potential analysis. RESULTS: R-configured TXs (TX-2043, -2030, -2036) had a weaker radiosensitizing activity than S-configured TXs (TX-2044, -2031, -2037), and R-compounds had a small minus electrostatic potential (ESP) field in the cyclopentene-1,3-dione region. S-configured TX-2046 had weaker radiosensitizing activity than R-configured TX-2045, and TX-2046 had a small minus ESP field as well as R-configured TX-2043, -2030, - 2036. CONCLUSION: The cyclopentene-1,3-dione involved in the small minus ESP field affected the radiosensitizing activity of the TX-2036 series of molecules.


Assuntos
Desenho de Drogas , Nitroimidazóis/química , Tolerância a Radiação/efeitos dos fármacos , Radiossensibilizantes/química , Hipóxia Celular/efeitos dos fármacos , Ciclopentanos/síntese química , Ciclopentanos/química , Humanos , Nitroimidazóis/síntese química , Radiossensibilizantes/síntese química , Eletricidade Estática , Estereoisomerismo , Relação Estrutura-Atividade
9.
Ecotoxicol Environ Saf ; 183: 109491, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31377517

RESUMO

Triticonazole and prothioconazole are widely used systemic agricultural triazole fungicides both with a chiral center. In this work, the enantioselective degradation of triticonazole and prothioconazole in three types of soils were investigated under native conditions using reversed phase liquid chromatography-tandem mass spectrometry with a Chiralcel OD-RH column. The results indicated that the enantioselective degradation was observed with S-triticonazole and R-prothioconazole preferentially degraded and the degradation rate was fast with a half-life within 6 days. It was also found that the presence of earthworms can accelerate the degradation and further enhance degradation enantioselectivity of triticonazole and prothioconazole in soils. Moreover, the enantioselective of triticonazole and prothioconazole in earthworms were studied. The results showed that the bioaccumulation was enantioselective with R-triticonazole and S-prothioconazole preferentially accumulated, which was similar to the soil. Our findings suggest that the enantioselective toxicity and potential effects of the metabolites should be considered for more accurate assessment of ecological risks of triticonazole and prothioconazole to target and non-target species.


Assuntos
Ciclopentanos/metabolismo , Fungicidas Industriais/metabolismo , Oligoquetos/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Triazóis/metabolismo , Animais , Biodegradação Ambiental , Ciclopentanos/química , Fungicidas Industriais/química , Poluentes do Solo/química , Estereoisomerismo , Triazóis/química
10.
Molecules ; 24(14)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295845

RESUMO

A recent computational analysis of the stabilizing intramolecular OH⋯O contact in 1,2-dialkyl-2,3-epoxycyclopentanol diastereomers has been extended to thiiriane, aziridine and phosphirane analogues. Density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2) and CCSD(T) coupled-cluster computations with simple methyl and ethyl substituents indicate that electronic energies of the c i s isomers are lowered by roughly 3 to 4 kcal mol-1 when the OH group of these cyclopentanol systems forms an intramolecular contact with the O, S, N or P atom on the adjacent carbon. The results also suggest that S and P can participate in these stabilizing intramolecular interactions as effectively as O and N in constrained molecular environments. The stabilizing intramolecular OH⋯O, OH⋯S, OH⋯N and OH⋯P contacts also increase the covalent OH bond length and significantly decrease the OH stretching vibrational frequency in every system with shifts typically on the order of -41 cm-1.


Assuntos
Aziridinas/química , Ciclopentanos/química , Compostos de Epóxi/química , Modelos Teóricos , Sulfetos/química , Teoria da Densidade Funcional , Ligações de Hidrogênio , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Estrutura Molecular
11.
Environ Sci Pollut Res Int ; 26(27): 27761-27768, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31342350

RESUMO

Ozone (O3) is an adverse environmental factor posing damage to ornamental plants. Thus, it is important to seek an effective way of enhancing plant tolerance to O3-induced damage. Methyl jasmonate (MJ) and melatonin (MT) are plant growth regulators (PGRs) involved in plant abiotic stress responses. In this study, compared with the control group of plants without ozone, the influence of exogenous MJ (0, 10, 50, 100, and 150 µM) and MT (0, 0.1, 0.5, 2.5, and 12.5 µM) on the resistance of Malus crabapple 'Hong Jiu' was evaluated under O3 stress (100 ± 10 nL/L for 3 h). Our data revealed that levels of MDA were significantly enhanced following O3 treatment compared with plants without O3. O3 induced the activities of antioxidant enzymes and the accumulation of non-enzymatic antioxidants. While lower malondialdehyde (MDA) content, greater activities of antioxidant enzymes, and higher levels of soluble protein and non-enzymatic antioxidants were observed in PGRs-pretreated plants than in non-PGRs-pretreated plants under O3 stress. Based on the above results and air pollution tolerance index (APTI), an exogenous supply of MJ and MT to Malus crabapple 'Hong Jiu' seedlings was protective for O3-induced toxicity. The present study provides new insights into the mechanisms of MJ and MT amelioration of O3-induced oxidative stress damages in Malus crabapple 'Hong Jiu.'


Assuntos
Acetatos/química , Antioxidantes/química , Ciclopentanos/química , Malus/metabolismo , Melatonina/química , Oxilipinas/química , Ozônio/toxicidade , Acetatos/metabolismo , Antioxidantes/metabolismo , Ciclopentanos/metabolismo , Malondialdeído/metabolismo , Malus/química , Melatonina/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Oxilipinas/metabolismo , Plântula/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos
12.
Molecules ; 24(14)2019 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-31330867

RESUMO

Three new γ-hydroxyl butenolides (1-3), a pair of new enantiomeric spiro-butenolides (4a and 4b), a pair of enantiomeric cyclopentenones (5a new and 5b new natural), and six known compounds (6-11), were isolated from Aspergillus sclerotiorum. Their structures were established by spectroscopic data and electronic circular dichroism (ECD) spectra. Two pairs of enantiomers [(+)/(-)-6c and (+)/(-)-6d] obtained from the reaction of 6 with acetyl chloride (AcCl) confirmed that 6 was a mixture of two pairs of enantiomers. In addition, the X-ray data confirmed that 7 was also a racemate. The new metabolites (1-5) were evaluated for their inhibitory activity against cancer and non-cancer cell lines. As a result, compound 1 exhibited moderate cytotoxicity to HL60 and A549 with IC50 values of 6.5 and 8.9 µM, respectively, and weak potency to HL-7702 with IC50 values of 17.6 µM. Furthermore, compounds 1-9 were screened for their antimicrobial activity using the micro-broth dilution method. MIC values of 200 µg/mL were obtained for compounds 2 and 3 towards Staphylococcus aureus and Escherichia coli, while compound 8 exhibited a MIC of 50 µ/mL towards Candida albicans.


Assuntos
4-Butirolactona/análogos & derivados , Aspergillus/química , Ciclopentanos/química , Microbiologia do Solo , Solo/química , 4-Butirolactona/química , 4-Butirolactona/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ciclopentanos/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Análise Espectral , Relação Estrutura-Atividade
13.
Chemosphere ; 235: 734-748, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31280042

RESUMO

Jasmonic acid (JA) is an important phytohormone associated in defense responses against stress. Crop plants experience heavy metal toxicity and needs to be explored to enhance the crop production. Lead (Pb) is one of the dangerous heavy metal that pollutes soil and water bodies and is released from various sources like discharge from batteries, automobile exhaust, and paints. The present study was designed to evaluate the role of JA (100 nM) on photosynthetic pigments, secondary metabolites, organic acids, and metal ligation compounds in tomato seedlings under different concentrations of Pb (0.25, 0.50, and 0.75 mM). It was observed that Pb treatment declined pigment content, relative water content, and heavy metal tolerance index. Expression of chlorophyllase was also enhanced in Pb-treated seedlings. Seeds primed with JA lowered the expression of chlorophyllase under Pb stress. JA application enhanced the contents of secondary metabolites (total phenols, polyphenols, flavonoids, and anthocyanin) which were confirmed with enhanced expression of chalcone synthase and phenylalanine ammonia lyase in Pb-exposed seedlings. Treatment of JA further elevated the levels of organic acids and metal chelating compounds under Pb toxicity. JA up-regulated the expression of succinate dehydrogenase and fumarate hydratase in Pb-exposed seedlings. Results revealed that seeds primed with JA reduced Pb toxicity by elevating, the levels of photosynthetic pigments, secondary metabolites, osmolytes, metal ligation compounds, organic acids, and polyamine accumulation in tomato seedlings.


Assuntos
Ciclopentanos/química , Chumbo/química , Lycopersicon esculentum/fisiologia , Oxilipinas/química , Poluentes do Solo/química , Ciclopentanos/metabolismo , Expressão Gênica , Inativação Metabólica/genética , Chumbo/metabolismo , Chumbo/toxicidade , Lycopersicon esculentum/genética , Lycopersicon esculentum/metabolismo , Oxilipinas/metabolismo , Fenóis/metabolismo , Fotossíntese , Reguladores de Crescimento de Planta/metabolismo , Polifenóis/metabolismo , Plântula/metabolismo , Sementes/metabolismo , Poluentes do Solo/toxicidade
14.
Org Biomol Chem ; 17(24): 5951-5961, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31166343

RESUMO

The syntheses of conduramine B-2, ent-conduramine F-2, aminocyclopentitol and trihydroxyazepane were accomplished from a common precursor, through a divergent approach using ring closing metathesis (RCM) as the key step. Tri-O-benzyl-d-glucal was converted to 3,4,6-tri-O-benzyl-1,2-dideoxy-2-iodo-1-p-toluenesulfonamido-α-d-mannose. Exposure to NaBH4 in MeOH resulted in a facile 1,2-transposition of the -NHTs group with concomitant glycosylation to give methyl 3,4,6-tri-O-benzyl-2-deoxy-2-p-toluenesulfonamido-ß-d-glucoside, which was converted into methyl 6-deoxy-6-iodo-glucoside in three steps. Zinc-mediated Vasella's rearrangement proceeded smoothly to give the pluripotent formyl-olefin, possessing both electrophilic and nucleophilic sites, which was used as a common precursor in our diversity-oriented approach. Vinylation of the carbonyl group followed by RCM and subsequent deprotection resulted in the successful synthesis of conduramine B-2 and ent-conduramine F-2 for the first time. On the other hand, the Wittig reaction of the formyl-olefin affords the diene that undergoes Grubbs' I catalyzed RCM and deprotection/reduction to provide 3-amino-cyclopentan-1,2-diol. Utilizing the nucleophilic site at the nitrogen of the common precursor, base mediated N-allylation was carried out to obtain the corresponding diene that underwent a smooth RCM to afford trihydroxyazepane.


Assuntos
Azepinas/síntese química , Cicloexilaminas/síntese química , Ciclopentanos/síntese química , Azepinas/química , Cicloexilaminas/química , Ciclopentanos/química , Glicosilação , Estrutura Molecular
15.
Plant Mol Biol ; 100(6): 659-674, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31187392

RESUMO

KEY MESSAGE: Oxalotrophic Stenotrophomonas isolated from tomato rhizosphere are able to protect plants against oxalate-producing pathogens by a combination of actions including induction of plant defence signalling callose deposition and the strengthening of plant cell walls and probably the degradation of oxalic acid. Oxalic acid plays a pivotal role in the virulence of the necrotrophic fungi Botrytis cinerea and Sclerotinia sclerotiorum. In this work, we isolated two oxalotrophic strains (OxA and OxB) belonging to the bacterial genus Stenotrophomonas from the rhizosphere of tomato plants. Both strains were capable to colonise endophytically Arabidopsis plants and protect them from the damage caused by high doses of oxalic acid. Furthermore, OxA and OxB protected Arabidopsis from S. sclerotiorum and B. cinerea infections. Bacterial inoculation induced the production of phenolic compounds and the expression of PR-1. Besides, both isolates exerted a protective effect against fungal pathogens in Arabidopsis mutants affected in the synthesis pathway of salicylic acid (sid2-2) and jasmonate perception (coi1). Callose deposition induced by OxA and OxB was required for protection against phytopathogens. Moreover, B. cinerea and S. sclerotiorum mycelial growth was reduced in culture media containing cell wall polysaccharides from leaves inoculated with each bacterial strain. These findings suggest that cell walls from Arabidopsis leaves colonised by these bacteria would be less susceptible to pathogen attack. Our results indicate that these oxalotrophic bacteria can protect plants against oxalate-producing pathogens by a combination of actions and show their potential for use as biological control agents against fungal diseases.


Assuntos
Fungos/patogenicidade , Lycopersicon esculentum/microbiologia , Oxalatos/metabolismo , Stenotrophomonas/fisiologia , Arabidopsis/metabolismo , Botrytis/metabolismo , Botrytis/patogenicidade , Parede Celular/metabolismo , Ciclopentanos/química , Fungos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácido Oxálico/metabolismo , Oxilipinas/química , Filogenia , Doenças das Plantas/microbiologia , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Polissacarídeos/metabolismo , Ácido Salicílico/farmacologia , Transdução de Sinais , Stenotrophomonas/isolamento & purificação
16.
Plant Physiol Biochem ; 141: 193-201, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31174036

RESUMO

Centipedegrass (Eremochloa ophiuroides [Munro] Hack.) is a warm-season turfgrass, widely planted in residential lawns and recreational fields. Here, we uncovered three major terpenes released from the shoots of Eo: (E)-ß-ocimene (6%), α-muurolene (87.8%), and eremophilene (6.2%). Methyl jasmonate (MeJA) treatment increased the emission of monoterpenes, including (E)- and (Z)-ß-ocimene, limonene, and myrcene, as well as sesquiterpene blends of (E)-caryophyllene, α-copaene, (+)-cyclosativene, and α-farnesene. RNA sequencing analysis predicted 14 putative Eo terpene synthase (EoTPS) genes, and two full-length EoTPS were successfully amplified: Eo7816 (1722 bp) and Eo6039 (1701 bp). Phylogenetic analysis revealed that Eo7816 and Eo6039 belonged to the clades of TPS-b and TPS-a, respectively. The Arabidopsis transgenic plants overexpressing Eo7816 exclusively released (E)-ß-ocimene (96%) with (Z)-ß-ocimene and myrcene. In contrast, Eo6039-overexpressing Arabidopsis plants emitted significant amounts of α-muurolene (69.4%) and eremophilene (21.8%). Together, we demonstrated that the two TPSs play roles in producing major volatile terpenes in Eo.


Assuntos
Acetatos/química , Alquil e Aril Transferases/metabolismo , Ciclopentanos/química , Oxilipinas/química , Poaceae/enzimologia , Terpenos/química , Transcriptoma , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Análise por Conglomerados , DNA Complementar/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Fenótipo , Filogenia , Proteínas de Plantas/metabolismo , RNA Mensageiro/metabolismo , Análise de Sequência de RNA , Sesquiterpenos/química
17.
Plant Physiol Biochem ; 141: 142-153, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31163341

RESUMO

Plant growth promoting bacteria (PGPB) are agriculturally important soil bacteria that increase plant growth. We subjected peppermint to inoculation with three species of PGPB. After inoculation, the plants were sprayed with methyl jasmonate solution (MeJA) or SA (salicylic acid). Then, the plants were harvested and the plant growth parameters, trichome density, EO content and endogenous phytohormones were measured. Shoot fresh weight was reduced in plants inoculated and treated with MeJA whereas EO content varied depending on the MeJA concentration applied. Plants inoculated and treated with MeJA 2 mM showed the maximum increase in EO production, revealing a synergism between PGPB and MeJA. SA treatments also enhanced EO yield. The increased growth and EO production observed upon PGPB application were at least partly due to an increase in the JA and SA concentrations in the plant, as well as to an associated rise in the glandular trichome density.


Assuntos
Acetatos/farmacologia , Ciclopentanos/química , Ciclopentanos/farmacologia , Mentha piperita/química , Óleos Voláteis/química , Oxilipinas/química , Oxilipinas/farmacologia , Ácido Salicílico/química , Tricomas/química , Bacillus subtilis , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Mentha piperita/microbiologia , Óleos Voláteis/isolamento & purificação , Desenvolvimento Vegetal , Reguladores de Crescimento de Planta/química , Folhas de Planta/química , Brotos de Planta/química , Pseudomonas fluorescens , Pseudomonas putida
18.
Chin J Nat Med ; 17(5): 387-393, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31171274

RESUMO

Replacement of the native promoter of theglobal regulator LaeA-like gene of Daldinia eschscholzii by a strong gpdA promoter led to the generation of two novel cyclopentenone metabolites, named dalestones A and B, whose structures were assigned by a combination of spectroscopic analysis, modified Mosher's reaction, and electronic circular dichroism (ECD). Dalestones A and B inhibit the gene expression of TNF-α and IL-6 in LPS-induced RAW264.7 macrophages.


Assuntos
Anti-Inflamatórios/farmacologia , Ciclopentanos/farmacologia , Proteínas Fúngicas/genética , Regiões Promotoras Genéticas/genética , Fatores de Transcrição/genética , Xylariales/química , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/metabolismo , Ciclopentanos/química , Ciclopentanos/isolamento & purificação , Ciclopentanos/metabolismo , Proteínas Fúngicas/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Estrutura Molecular , Células RAW 264.7 , Fatores de Transcrição/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Xylariales/genética , Xylariales/metabolismo
19.
Inorg Chem ; 58(14): 9135-9149, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31241925

RESUMO

Prospective anticancer metallodrugs should consider target-specific components in their design in order to overcome the limitations of the current chemotherapeutics. The inclusion of vitamins, which receptors are overexpressed in many cancer cell lines, has proven to be a valid strategy. Therefore, in this paper we report the synthesis and characterization of a set of new compounds [Ru(η5-C5H5)(P(C6H4R)3)(4,4'-R'-2,2'-bpy)]+ (R = F and R' = H, 3; R = F and R' = biotin, 4; R = OCH3 and R' = H, 5; R = OCH3 and R' = biotin, 6), inspired by the exceptional good results recently obtained for the analogue bearing a triphenylphosphane ligand. The precursors for these syntheses were also described following modified literature procedures, [Ru(η5-C5H5)(P(C6H4R)3)2Cl], where R is -F (1) or -OCH3 (2). The structure of all compounds is fully supported by spectroscopic and analytical techniques and by X-ray diffraction studies for compounds 2, 3, and 5. All cationic compounds are cytotoxic in the two breast cancer cell lines tested, MCF7 and MDA-MB-231, and much better than cisplatin under the same experimental conditions. The cytotoxicity of the biotinylated compounds seems to be related with the Ru uptake by the cells expressing biotin receptors, indicating a potential mediated uptake. Indeed, a biotin-avidin study confirmed that the attachment of biotin to the organometallic fragment still allows biotin recognition by the protein. Therefore, the biotinylated compounds might be potent anticancer drugs as they show cytotoxic effect in breast cancer cells at low dose dependent on the compounds' uptake, induce cell death by apoptosis and inhibit the colony formation of cancer cells causing also less severe side effects in zebrafish.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Biotina/química , Ciclopentanos/química , Compostos de Rutênio/síntese química , Animais , Antineoplásicos/toxicidade , Biotina/farmacologia , Biotinilação , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Cristalografia por Raios X , Ciclopentanos/farmacologia , Humanos , Estrutura Molecular , Compostos de Rutênio/química , Compostos de Rutênio/farmacologia , Testes de Toxicidade , Peixe-Zebra
20.
Org Lett ; 21(10): 3554-3557, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31058517

RESUMO

The first total synthesis of pactalactam was accomplished using substrate-controlled stereoselective aziridination and regioselective aziridine ring-opening to construct three continuous amino groups on an octasubstituted cyclopentane core. The cyclopentane framework was obtained by ring-closing metathesis and aldol coupling using a l-threonine-derived oxazoline compound. Cyclic urea formation, m-acetylphenyl group introduction by Chan-Lam coupling, and primary alcohol-selective acylation yielded the reported pactalactam structure. The presence of pactalactam in the fermentation broth of pactamycin-producing bacteria was also confirmed.


Assuntos
Álcoois/química , Aziridinas/química , Ciclopentanos/química , Imidazolidinas/síntese química , Pactamicina/síntese química , Acilação , Imidazolidinas/química , Estrutura Molecular , Pactamicina/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA