Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Cell ; 187(10): 2557-2573.e18, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38729111

RESUMO

Many of the world's most devastating crop diseases are caused by fungal pathogens that elaborate specialized infection structures to invade plant tissue. Here, we present a quantitative mass-spectrometry-based phosphoproteomic analysis of infection-related development by the rice blast fungus Magnaporthe oryzae, which threatens global food security. We mapped 8,005 phosphosites on 2,062 fungal proteins following germination on a hydrophobic surface, revealing major re-wiring of phosphorylation-based signaling cascades during appressorium development. Comparing phosphosite conservation across 41 fungal species reveals phosphorylation signatures specifically associated with biotrophic and hemibiotrophic fungal infection. We then used parallel reaction monitoring (PRM) to identify phosphoproteins regulated by the fungal Pmk1 MAPK that controls plant infection by M. oryzae. We define 32 substrates of Pmk1 and show that Pmk1-dependent phosphorylation of regulator Vts1 is required for rice blast disease. Defining the phosphorylation landscape of infection therefore identifies potential therapeutic interventions for the control of plant diseases.


Assuntos
Proteínas Fúngicas , Oryza , Doenças das Plantas , Fosforilação , Oryza/microbiologia , Oryza/metabolismo , Doenças das Plantas/microbiologia , Proteínas Fúngicas/metabolismo , Fosfoproteínas/metabolismo , Ascomicetos/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteômica , Transdução de Sinais
2.
Plant Cell ; 35(5): 1360-1385, 2023 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-36808541

RESUMO

The rice blast fungus Magnaporthe oryzae causes a devastating disease that threatens global rice (Oryza sativa) production. Despite intense study, the biology of plant tissue invasion during blast disease remains poorly understood. Here we report a high-resolution transcriptional profiling study of the entire plant-associated development of the blast fungus. Our analysis revealed major temporal changes in fungal gene expression during plant infection. Pathogen gene expression could be classified into 10 modules of temporally co-expressed genes, providing evidence for the induction of pronounced shifts in primary and secondary metabolism, cell signaling, and transcriptional regulation. A set of 863 genes encoding secreted proteins are differentially expressed at specific stages of infection, and 546 genes named MEP (Magnaportheeffector protein) genes were predicted to encode effectors. Computational prediction of structurally related MEPs, including the MAX effector family, revealed their temporal co-regulation in the same co-expression modules. We characterized 32 MEP genes and demonstrate that Mep effectors are predominantly targeted to the cytoplasm of rice cells via the biotrophic interfacial complex and use a common unconventional secretory pathway. Taken together, our study reveals major changes in gene expression associated with blast disease and identifies a diverse repertoire of effectors critical for successful infection.


Assuntos
Ascomicetos , Magnaporthe , Oryza , Magnaporthe/fisiologia , Ascomicetos/metabolismo , Transdução de Sinais , Citoplasma/metabolismo , Oryza/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
3.
PLoS Biol ; 21(4): e3002052, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37040332

RESUMO

Wheat, one of the most important food crops, is threatened by a blast disease pandemic. Here, we show that a clonal lineage of the wheat blast fungus recently spread to Asia and Africa following two independent introductions from South America. Through a combination of genome analyses and laboratory experiments, we show that the decade-old blast pandemic lineage can be controlled by the Rmg8 disease resistance gene and is sensitive to strobilurin fungicides. However, we also highlight the potential of the pandemic clone to evolve fungicide-insensitive variants and sexually recombine with African lineages. This underscores the urgent need for genomic surveillance to track and mitigate the spread of wheat blast outside of South America and to guide preemptive wheat breeding for blast resistance.


Assuntos
Pandemias , Triticum , Triticum/genética , Melhoramento Vegetal , Doenças das Plantas/microbiologia , Genômica , Fungos
4.
Ecotoxicol Environ Saf ; 270: 115842, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38104434

RESUMO

To reduce the application dosage of thiamethoxam (TMX), we investigated the deposition and dissipation patterns in a pepper-planted ecosystem under different planting modes across four regions in China, namely Hainan (HN), Zhejiang (ZJ), Anhui (AH) and Hebei (HB). This study focused on the deposition and dissipation of TMX at concentrations of 63.00, 47.25, 31.50, 23.63 and 15.75 g a.i.hm-2. As the application dose increased, the deposition amount of TMX initially increased in the plants and cultivated soil, showing obvious geographic differences in four cultivation areas. Surprisingly, the initial amount of TMX deposited the pepper-cultivated greenhouse of ZJ and AH was 1.1-2.1-fold and 1.0-3.6-fold higher than that in the open field system at the same application dose, respectively. In pepper leaves, stems, fruits and soil, the dissipation exhibited rapid growth and then slowed. However, the residual concentration showed an increasing trend, followed by a subsequent decrease in the pepper roots. In different planting regions, the dissipation rate of TMX followed the order HN > ZJ > AH > HB in pepper plants and cultivated soil. In comparison to the open field, the total TMX retention rate in greenhouse was higher, indicating overall greater persistence in the greenhouse conditions. These findings reveal the deposition and dissipation characteristics of TMX within the pepper-field ecosystem, offering a significant contribution to the risk assessment of pesticides.


Assuntos
Inseticidas , Praguicidas , Tiametoxam , Inseticidas/análise , Ecossistema , Solo
5.
BMC Neurol ; 23(1): 119, 2023 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-36964484

RESUMO

BACKGROUND: Acute bilateral occlusion of the middle cerebral artery (MCA) is a very rare condition, and most cases are accompanied by a poor prognosis. However, mechanical thrombectomy (MT) for bilateral MCA is challenging. Here, we report a case of acute unilateral MCA occlusion with sequential acute occlusion of the bilateral MCA during intravenous thrombolysis (IVT). We urgently performed bilateral MT of the MCA and effective recanalization. CASE PRESENTATION: The patient is a 73-year-old man who complained of a sudden adverse influence on speech and an inability to move his left limb for 2 h. He had a history of paroxysmal atrial fibrillation, but had never used any anticoagulants before. Head and neck computed tomography angiography (CTA) showed embolism in the right M1 MCA. During intravenous alteplase thrombolytic therapy, the patient suddenly became unconscious. Cerebral angiography showed occlusion of the M1 segment of the bilateral MCA in the patients. MT of the bilateral MCA was performed using a combination of a stent retriever and an aspiration catheter with mTici 3 revascularization. On the second day, the patient became conscious, although he had remaining symptoms of speech insufficiency and weakness of the left limb. The mRS score was 2 90 days after the operation. CONCLUSIONS: Acute bilateral occlusion of the M1 segment of the MCA is extremely rare and is accompanied by high morbidity and high mortality. Intravenous alteplase thrombolysis can increase the risk of atrial thrombus shedding in patients with atrial fibrillation, so patients with acute bilateral MCA occlusion in the M1 segment chose direct MT or bridging therapy, which remains controversial, and the sequence of MT remains to be discussed. Nevertheless, early endovascular treatment can decrease the morbidity and mortality of such patients.


Assuntos
Infarto da Artéria Cerebral Média , Acidente Vascular Cerebral , Masculino , Humanos , Idoso , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Infarto da Artéria Cerebral Média/cirurgia , Ativador de Plasminogênio Tecidual/uso terapêutico , Trombectomia/métodos , Fibrinolíticos/uso terapêutico , Terapia Trombolítica/métodos , Artéria Cerebral Média , Resultado do Tratamento , Acidente Vascular Cerebral/complicações
6.
BMC Anesthesiol ; 23(1): 154, 2023 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-37142982

RESUMO

BACKGROUND: Postoperative sleep disturbance (PSD) is a prevalent clinical complication that may arise due to various factors. The purpose of this investigation is to identify the risk factors for PSD in spinal surgery and establish a risk prediction nomogram. METHODS: The clinical records of individuals who underwent spinal surgery from January 2020 to January 2021 were gathered prospectively. The least absolute shrinkage and selection operator (LASSO) regression, along with multivariate logistic regression analysis, was employed to establish independent risk factors. A nomogram prediction model was devised based on these factors. The nomogram's effectiveness was evaluated and verified via the receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis (DCA). RESULTS: A total of 640 patients who underwent spinal surgery were analyzed in this investigation, among which 393 patients experienced PSD with an incidence rate of 61.4%. After conducting LASSO regression and logistic regression analyses using R software on the variables in training set, 8 independent risk factors associated to PSD were identified, including female, preoperative sleep disorder, high preoperative anxiety score, high intraoperative bleeding volume, high postoperative pain score, dissatisfaction with ward sleep environment, non-use of dexmedetomidine and non-use of erector spinae plane block (ESPB). The nomogram and online dynamic nomogram were constructed after incorporating these variables. In the training and validation sets, the area under the curve (AUC) in the receiver operating characteristic (ROC) curves were 0.806 (0.768-0.844) and 0.755 (0.667-0.844), respectively. The calibration plots indicated that the mean absolute error (MAE) values in both sets were respectively 1.2% and 1.7%. The decision curve analysis demonstrated the model had a substantial net benefit within the range of threshold probabilities between 20% and 90%. CONCLUSIONS: The nomogram model proposed in this study included eight frequently observed clinical factors and exhibited favorable accuracy and calibration. TRIAL REGISTRATION: The study was retrospectively registered with the Chinese Clinical Trial Registry (ChiCTR2200061257, 18/06/2022).


Assuntos
Nomogramas , Transtornos do Sono-Vigília , Adulto , Feminino , Humanos , Povo Asiático , Procedimentos Neurocirúrgicos , Estudos Prospectivos
7.
J Sci Food Agric ; 102(5): 1842-1850, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-34460956

RESUMO

BACKGROUND: Since anthocyanin has good coloration and antioxidant properties, many studies have focused on exploring the stability and antioxidant activity of anthocyanin. The objective of this work was to study effects of pH and temperature on the bioactivity of cyanidin-3-O-glucoside (C3G) and ultra-performance liquid chromatography-photodiode array-electrospray ionization-quadrupole-time-of-flight mass spectrometry (UPLC-PDA-ESI-Q-TOF-MS) and density functional theory (DFT) were used to explain the mechanism of structural transformation of C3G affecting their bioactivity at the molecular level. RESULTS: During the heating process at pH 2.2 to 7.0,the flavylium cation content of C3G decreased from 92.71% to 51.64% and the chalcone content increased from 7.29% to 30.61%. The quinoidal base and first discovery of the degradation product of the C3G, 1-(3,4-dihydroxy-phenyl)-2-(3, 4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-ethanone, were only detected in heated samples at pH 7.0. DFT revealed the antioxidant mechanism was mediated by sequential proton loss electron transfer and the antioxidant activity of C3G in pH 5.0 and 7.0 environments was higher than that in the pH 2.2 environment. CONCLUSIONS: The results revealed the thermal degradation products of C3G included catechin, 3,4-dihydroxybenzoic acid, 2,4,6-trihydroxy-benzaldehyde and 1-(3,4-Dihydroxy-phenyl)-2-(3,4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-ethanone. C3G had higher antioxidant activity in weakly acidic to near-neutral environments and the reactive sites were most likely at the 4'-OH and 5-OH sites. © 2021 Society of Chemical Industry.


Assuntos
Antocianinas , Glycine max , Antocianinas/química , Antioxidantes/química , Glucosídeos/metabolismo , Temperatura Alta , Concentração de Íons de Hidrogênio , Glycine max/química
8.
Bull Environ Contam Toxicol ; 108(4): 629-634, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34613433

RESUMO

To develop high-performance biochar adsorbents, the adsorption ability and rate of untreated (BC-CK) and six modified biochars with amino (BC-NH), epoxy (BC-C2H2O), ethoxy (BC-C2H5O), hydrosulfuryl (BC-SH), selenium (BC-Se), and chitosan (BC-Chitosan) on Hg(II) and MeHg were investigated by simulated experiment. The results indicated that the some modified biochars (BC-NH, BC-C2H2O, BC-C2H5O and BC-Chitosan) showed lower adsorption capacity than the untreated, possibly due to the decreased specific surface area and pore volume. Whereas, BC-SH and BC-Se was improved immensely by forming stable -SH-Hg and Hg-Se with the adsorption capacity 1.26 and 1.51 times as much as BC-CK, respectively. In spite of that, Hg desorption capacities and rates of all biochars were extremely low, exhibiting great adsorption stability of biochars on Hg in another way. In addition, BC-Chitosan performed the highest adsorption speed. These provided insights on the adsorption effectiveness for Hg in the aqueous solution that was critical for evaluating the application of modified biochars.


Assuntos
Mercúrio , Adsorção , Carvão Vegetal
9.
Ecotoxicol Environ Saf ; 228: 112995, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34801924

RESUMO

Rapid and sensitive detection of mercury vapor is of great significance for environmental protection and human health. But the detection method enabling low detection limitation and rapid response at room temperature simultaneously has rarely been reported. In this work, we propose a gold particles decorated reduced graphene oxide sensor for mercury vapor detection. After adding the gold particles, the reduced graphene oxide sensors' response sensitivity increase by more than 16 times and the response time significantly decreases, which is far less below the results reported by others. The sensor performance improvement should attribute to the distribution of the decorated gold particles, which insert into the layered graphene sheets, as demonstrated by the SEM and XRD results. The increased layer spacing of graphene sheets is conductive to the faster entry/exit of mercury vapor and increases the effective sensing area of graphene. What's more, the first-principles calculation results confirm the mercury-philicity of gold particles, which also contributes to the increased sensitivity. We further test more performance of the gold particles decorated reduced graphene oxide sensor to mercury vapor, which shows a linear response, low detection limit and good repeatability. The proposed sensor shows rapid response/recovery (6/8 s), low detection limit (0.01 ng/mL), linear response, good repeatability and room temperature detection simultaneously, which shows great application potential for mercury vapor detection.

10.
Angew Chem Int Ed Engl ; 60(13): 7188-7196, 2021 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-33354826

RESUMO

Calix[4]pyrrole-based porous organic polymers (P1-P3) for removing organic micropollutants from water were prepared. A bowl-shaped α,α,α,α-tetraalkynyl calix[4]pyrrole and diketopyrrolopyrrole monomer were crosslinked via Sonogashira coupling to produce a 3D network polymer, P1. P1 proved too hydrophobic for use as an adsorbent and was converted to the corresponding neutral polymer P2 (containing carboxylic acid groups) and its anionic derivative P3 (containing carboxylate anion groups). Anionic P3 outperformed P2 in screening studies involving a variety of model organic micropollutants of different charge, hydrophilicity and functionality. P3 proved particularly effective for cationic micropollutants. The theoretical maximum adsorption capacity (qmax,e ) of P3 reached 454 mg g-1 for the dye methylene blue, 344 mg g-1 for the pesticide paraquat, and 495 mg g-1 for diquat. These uptake values are significantly higher than those of most synthetic adsorbent materials reported to date.

11.
Glycoconj J ; 35(6): 547-559, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30343348

RESUMO

In this study, four main components of feruloylated oligosaccharides (FOs),FOs-1, FOs-2, FOs-3 and FOs-4,were isolated from wheat bran by use of Amberlite XAD-2 and Sephadex LH-20. Structural characterization of FOs was determined by use of high performance liquid chromatography (HPLC), gas chromatography (GC) and fourier transform-infrared spectroscopy (FT-IR). Antioxidant properties were investigated in vitro. Average degrees of polymerization (DP) of the four components (FOs-1, FOs-2, FOs-3 and FOs-4) were approximately 10.6, 7.7, 6.1 and 3.4, respectively. In addition, DP were consistent with molar ratios of arabinose and xylose in 1:9.46, 1:5.30, 1:2.91 and 1:0.19, respectively. The presence of ß-glycosidic linkage was confirmed at 896 cm - 1 by use of FT-IR. In vitro antioxidant studies demonstrated that FOs-1, FOs-2, FOs-3 and FOs-4 possessed significant antioxidant activities in the dose-dependent manner. In addition, the degree of polymerization affected antioxidant capacity. These results have improved our understanding of the relationship between FOs with different structural types and their antioxidant activities.


Assuntos
Antioxidantes/análise , Ácidos Cumáricos/análise , Fibras na Dieta/análise , Oligossacarídeos/análise , Polimerização , Compostos de Bifenilo/química , Quelantes/farmacologia , Cromatografia Líquida de Alta Pressão , Ácidos Cumáricos/química , Sequestradores de Radicais Livres/química , Radical Hidroxila/química , Íons , Metais/isolamento & purificação , Oligossacarídeos/química , Oligossacarídeos/isolamento & purificação , Picratos/química , Padrões de Referência , Espectroscopia de Infravermelho com Transformada de Fourier , Superóxidos/química
13.
Parasitol Res ; 113(10): 3631-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25015050

RESUMO

To seek natural products for the development of environment friendly mosquito control agents, fumigant activity of eleven essential oil compounds and the joint action of the active compounds were evaluated against Culex pipiens pallens adults. Fumigant bioassay demonstrated that carvacrol exhibited the highest fumigant activity followed by thymol and l-perillaldehyde, with LC50 values of 0.26, 0.28, and 0.34 mg/L air, respectively. Among the binary mixtures of four compounds with preferable performance, only the binary mixture of carvacrol and thymol (1:1, w/w) displayed a synergistic effect with the co-toxicity coefficient (CTC) value of 174.1 and LC50 value of 0.16 mg/L air. Furthermore, the actual efficacy of the binary mixture at 300 mg/mat (KT50 = 7.9, 15.8, and 22.0 min after 0, 2, and 4 h of preliminary heating, respectively) was comparable with that of d-allethrin at 30 mg/mat (KT50 = 8.7, 17.9, and 21.2 min after 0, 2, and 4 h of preliminary heating, respectively) tested in vaporizing mats by the glass chamber method (70 × 70 × 70 cm). These results revealed that carvacrol, thymol, and their binary mixture have potential for the development of natural fumigants for adult mosquito control.


Assuntos
Culex/efeitos dos fármacos , Inseticidas/farmacologia , Monoterpenos/farmacologia , Controle de Mosquitos/métodos , Óleos Voláteis/farmacologia , Timol/farmacologia , Animais , Bioensaio , Cimenos , Feminino , Fumigação , Dose Letal Mediana
14.
ScientificWorldJournal ; 2014: 742606, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25202735

RESUMO

To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m(-2) and 7.61 kg m(-2) day(-1) at the generation temperature of 140 °C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker.


Assuntos
Gelo , Energia Solar , Termodinâmica
15.
ScientificWorldJournal ; 2014: 128754, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24605046

RESUMO

Since air temperature records are readily available around the world, the models based on air temperature for estimating solar radiation have been widely accepted. In this paper, a new model based on Hargreaves and Samani (HS) method for estimating monthly average daily global solar radiation is proposed. With statistical error tests, the performance of the new model is validated by comparing with the HS model and its two modifications (Samani model and Chen model) against the measured data at 65 meteorological stations in China. Results show that the new model is more accurate and robust than the HS, Samani, and Chen models in all climatic regions, especially in the humid regions. Hence, the new model can be recommended for estimating solar radiation in areas where only air temperature data are available in China.


Assuntos
Modelos Teóricos , Luz Solar , China
16.
J Am Mosq Control Assoc ; 30(3): 199-203, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25843095

RESUMO

We studied the knockdown activity and lethal toxicity of 6 essential oil compounds-methyl salicylate, linalool, 2-phenethyl alcohol, eugenol, ß-citronellol, and trans-cinnamaldehyde-as fumigants against adult female Culex pipiens pallens in the laboratory. Of the 6 products tested, trans-cinnamaldehyde was the most toxic (LC50  =  0.26 µl/l air, 24 h) with a slow knockdown time (KT95  =  176.5 min at 0.5 µl/l air). Methyl salicylate displayed a lower toxicity (LC50  =  1.17 µl/l air, 24 h) but the fastest knockdown activity (KT95  =  16.8 min) at the sublethal concentration 0.5 µl/l air. Furthermore, the binary mixture of methyl salicylate and trans-cinnamaldehyde exhibited a combined effect of fast knockdown activity and high toxicity against Cx. p. pallens adults, showing potential for development as natural fumigants for mosquito control.


Assuntos
Acroleína/análogos & derivados , Culex , Fumigação , Inseticidas , Controle de Mosquitos , Óleos Voláteis , Salicilatos , Animais , Feminino
17.
PLoS One ; 19(6): e0304981, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38861574

RESUMO

Thin-bed soft rock is one of the main factors causing large deformations of tunnels. In addition to relying on some innovative construction techniques, detecting thin beds early during surface geological exploration and advanced geological prediction can provide a basis for planning and implementing effective coping measures. The commonly used seismic methods cannot meet the requirement for thin beds detection accuracy. A high-resolution (HR) seismic signal processing method is proposed by introducing a sequential convolutional neural network (SCNN). The deep learning dataset including low-resolution (LR) and HR seismic is firstly prepared through forward modeling. Then, a one-dimension (1D) SCNN architecture is proposed to establish the mapping relationship between LR and HR sequences. Training on the prepared dataset, the HR seismic processing model with high accuracy is achieved and applied to some practical seismic data. The applications on both poststack and prestack seismic data demonstrate that the trained HR processing model can effectively improve the seismic resolution and restore the high-frequency seismic energy so that to recognize the thin-bed rocks.


Assuntos
Redes Neurais de Computação , Geologia/métodos , Aprendizado Profundo , Terremotos
18.
J Agric Food Chem ; 72(23): 13371-13381, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38809574

RESUMO

The enzymatic biodegradation of mycotoxins in food and feed has attracted the most interest in recent years. In this paper, the laccase gene from Bacillus swezeyi was cloned and expressed in Escherichia coli BL 21(D3). The sequence analysis indicated that the gene consisted of 1533 bp. The purified B. swezeyi laccase was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis -12% with an estimated molecular weight of 56.7 kDa. The enzyme is thermo-alkali-tolerant, displaying the optimal degradation of zearalenone (ZEN) and aflatoxin B1 (AFB1) at pH 8 and 9, with incubation temperatures of 55 and 50 °C, respectively, within 24 h. The degradation potentials of the 50 µg of the enzyme against ZEN (5.0 µg/mL) and AFB1 (2.5 µg/mL) were 99.60 and 96.73%, respectively, within 24 h. To the best of our knowledge, this is the first study revealing the recombinant production of laccase from B. swezeyi, its biochemical properties, and potential use in ZEN and AFB1 degradation in vitro and in vivo.


Assuntos
Aflatoxina B1 , Bacillus , Proteínas de Bactérias , Estabilidade Enzimática , Lacase , Proteínas Recombinantes , Zearalenona , Lacase/genética , Lacase/metabolismo , Lacase/química , Aflatoxina B1/metabolismo , Aflatoxina B1/química , Zearalenona/metabolismo , Zearalenona/química , Bacillus/enzimologia , Bacillus/genética , Bacillus/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/química , Concentração de Íons de Hidrogênio , Temperatura , Peso Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Clonagem Molecular , Álcalis/metabolismo , Álcalis/química
19.
J Agric Food Chem ; 72(6): 3025-3035, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38300990

RESUMO

Zearalenone (ZEN) is a widespread mycotoxin that causes serious damage to animal husbandry and poses a threat to human health. A screen of ZEN-degrading soil bacteria yielded Bacillus subtilis YT-4, which yielded 80% ZEN degradation after 6 h and 95% after 36 h. The gene sequence encoding the degradative enzyme ZENY was mined from the genome of YT-4 and expressed in yeast. ZENY is an α/ß-hydrolase with an optimal enzyme activity at 37 °C and pH 8. By breaking the lactone ring of ZEN, it produces ZENY-C18H24O5 with a molecular weight of 320.16 g/mol. Sequence comparison and molecular docking analyses identified the catalytic ZENY triad 99S-245H-123E and the primary ZEN-binding mode within the hydrophobic pocket of the enzyme. To improve the thermal stability of the enzyme for industrial applications, we introduced a mutation at the N-terminus, specifically replacing the fifth residue N with V, and achieved a 25% improvement in stability at 45 °C. These findings aim to achieve ZEN biodegradation and provide insight into the structure and function of ZEN hydrolases.


Assuntos
Zearalenona , Animais , Humanos , Zearalenona/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Simulação de Acoplamento Molecular , Hidrolases/genética , Mutação
20.
J Agric Food Chem ; 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949246

RESUMO

Aflatoxin B1 is a notorious mycotoxin with mutagenicity and carcinogenicity, posing a serious hazard to human and animal health. In this study, an AFB1-degrading dipeptidyl-peptidase III mining from Aspergillus terreus HNGD-TM15 (ADPP III) with a molecular weight of 79 kDa was identified. ADPP III exhibited optimal activity toward AFB1 at 40 °C and pH 7.0, maintaining over 80% relative activity at 80 °C. The key amino acid residues that affected enzyme activity were identified as H450, E451, H455, and E509 via bioinformatic analysis and site-directed mutagenesis. The degradation product of ADPP III toward AFB1 was verified to be AFD1. The zebrafish hepatotoxicity assay verified the toxicity of the AFB1 degradation product was significantly weaker than that of AFB1. The result of this study proved that ADPP III presented a promising prospect for industrial application in food and feed detoxification.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA