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1.
J Exp Bot ; 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31996900

RESUMO

Teosinte branched1/cycloidea/proliferating (TCP) transcription factors (TFs) play a broad role in plant growth and development. However, the role of TCP proteins in the regulation of anthocyanin biosynthesis is rarely reported. In this study, different light intensity-induced anthocyanin biosynthesis was found to be largely dependent on the functions of MdMYB1 and MdTCP46 in apple. The expression of MdTCP46 was responsive to high light intensity, and the MdTCP46 protein promoted high light intensity-induced anthocyanin biosynthesis by enhancing the binding of MdMYB1 to its target genes through direct interactions with MdMYB1. Additionally, MdTCP46 interacted with a high light responsive BTB protein, MdBT2, which ubiquitinated MdTCP46 and mediated its degradation via the 26S proteasome pathway. These results demonstrate that the dynamic regulatory module, MdBT2-MdTCP46-MdMYB1, plays a key role in different light intensity-modulated anthocyanin biosynthesis in apple, which provides new insights for future studies on the post-transcriptional regulation of TCP proteins.

2.
Plant Sci ; 291: 110351, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31928678

RESUMO

Ethylene response factor (ERF) is a plant-specific transcription factor involved in many biological processes including root formation, hypocotyl elongation, fruit ripening, organ senescence and stress responses, as well as fruit quality formation. However, its underlying mechanism in plant pathogen defense against Botryosphaeria dothidea (B. dothidea) remains poorly understood. Here, we isolate MdERF11, an apple nucleus-localized ERF transcription factor, from apple cultivar 'Royal Gala'. qRT-PCR assays show that the expression of MdERF11 is significantly induced in apple fruits after B. dothidea infection. Overexpression of MdERF11 gene in apple calli significantly increases the resistance to B.dothidea infection, while silencing MdERF11 in apple calli results in reduced resistance. Ectopic expression of MdERF11 in Arabidopsis also exhibits enhanced resistance to B. dothidea infection compared to that of wild type. Infections in apple calli and Arabidopsis leaves by B. dothidea respectively cause an increase in endogenous levels of salicylic acid (SA) followed by induction of SA synthesis-related and signaling-related gene expression. Taken together, these findings illustrate a potential mechanism by which MdERF11 elevates plant pathogen defense against B. dothidea by regulating SA synthesis pathway.

3.
J Plant Physiol ; 244: 153089, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31812904

RESUMO

Inorganic phosphate (Pi) starvation severely affects the normal growth and development of plants. Here, a Pi-responsive gene, named MdMYB2 (MDP0000823458), was cloned and functionally identified in apple. Overexpression of MdMYB2 regulated the expression of Pi starvation-induced (PSI) genes and then promoted phosphate assimilation and utilization. The ectopic expression of MdMYB2 in Arabidopsis influenced plant growth and flowering, which was partially rescued by application of exogenous gibberellin (GA). These results indicated that MdMYB2 may be an essential regulator in phosphate utilization and GA-regulated plant growth and development.

4.
Plant J ; 101(3): 573-589, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31571281

RESUMO

Drought stress induces anthocyanin biosynthesis in many plant species, but the underlying molecular mechanism remains unclear. Ethylene response factors (ERFs) play key roles in plant growth and various stress responses, including affecting anthocyanin biosynthesis. Here, we characterized an ERF protein, MdERF38, which is involved in drought stress-induced anthocyanin biosynthesis. Biochemical and molecular analyses showed that MdERF38 interacted with MdMYB1, a positive modulator of anthocyanin biosynthesis, and facilitated the binding of MdMYB1 to its target genes. Therefore, MdERF38 promoted anthocyanin biosynthesis in response to drought stress. Furthermore, we found that MdBT2, a negative modulator of anthocyanin biosynthesis, decreased MdERF38-promoted anthocyanin biosynthesis by accelerating the degradation of the MdERF38 protein. In summary, our data provide a mechanism for drought stress-induced anthocyanin biosynthesis that involves dynamic modulation of MdERF38 at both transcriptional and post-translational levels.

5.
Plant Cell Physiol ; 61(1): 130-143, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31550006

RESUMO

As an important environment factor, light affects plant growth and development throughout life. B-BOX (BBX) proteins play key roles in the regulation of light signaling. Although the multiple roles of BBX proteins have been extensively studied in Arabidopsis, the research in apple is much less extensive. In this study, we systematically characterized the negative role of an apple BBX protein MdBBX37 in light signaling, including inhibiting anthocyanin biosynthesis and promoting hypocotyl elongation. We found that MdBBX37 interacted with MdMYB1 and MdMYB9, two key positive regulators of anthocyanin biosynthesis, and inhibited the binding of those two proteins to their target genes and, therefore, negatively regulated anthocyanin biosynthesis. In addition, MdBBX37 directly bound to the promoter of MdHY5, a positive regulator of light signaling, and suppressed its expression, and thus relieved MdHY5-mediated hypocotyl inhibition. Taken together, our investigations suggest that MdBBX37 is a negative regulator of light signaling in apple. Our study will provide reference for further study on the functions of BBX proteins in apple.

6.
Plant Biotechnol J ; 18(2): 337-353, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31250952

RESUMO

MYB transcription factors (TFs) have been demonstrated to play diverse roles in plant growth and development through interaction with basic helix-loop-helix (bHLH) TFs. MdbHLH33, an apple bHLH TF, has been identified as a positive regulator in cold tolerance and anthocyanin accumulation by activating the expressions of MdCBF2 and MdDFR. In the present study, a MYB TF MdMYB308L was found to also positively regulate cold tolerance and anthocyanin accumulation in apple. We found that MdMYB308L interacted with MdbHLH33 and enhanced its binding to the promoters of MdCBF2 and MdDFR. In addition, an apple RING E3 ubiquitin ligase MYB30-INTERACTING E3 LIGASE 1 (MdMIEL1) was identified to be an MdMYB308L-interacting protein and promoted the ubiquitination degradation of MdMYB308L, thus negatively regulated cold tolerance and anthocyanin accumulation in apple. These results suggest that MdMYB308L acts as a positive regulator in cold tolerance and anthocyanin accumulation in apple by interacting with MdbHLH33 and undergoes MdMIEL1-mediated protein degradation. The dynamic change in MYB-bHLH protein complex seems to play a key role in the regulation of plant growth and development.

7.
Enzyme Microb Technol ; 133: 109460, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31874685

RESUMO

Synthetic enzyme complexes have been successfully used to accelerate the reaction rate of cascade enzyme biocatalysis. Protein scaffold-mediated enzyme complexes are often constructed by assembling cascade enzymes on the artificial protein scaffoldin to form sophisticated biomimetic architectures and enhance the catalytic efficiency of biocatalytic processes. However, the effects of the linker in scaffoldin on the performance of the enzyme complexes have not been clarified. In this study, a scaffoldin-mediated two-enzyme complex containing triosephosphate isomerase (TIM) and fructose-1,6-bisphosphate aldolase/phosphatase (FBPA) was constructed, and the initial production rate of fructose 6-phosphate (F6P) was determined with different types of fine-tuning linkers. Enzyme complexes with linker length of 25 amino acids in scaffoldin exhibited the highest initial F6P production rate compared with linker length of 0, 10, or 57 amino acids in scaffoldin. This result indicated that an appropriate interdomain spacing between functional domains was required by multienzyme complexes to facilitate effective cascade catalysis. Then, the most popular flexible linker GGGGS (unit F) and rigid linker EAAAK (unit R) were introduced into this 25 amino acid linker to investigate the effect of linker flexibility on the initial reaction rate of the TIM-FBPA enzyme complex. The synthetic enzyme complex with the semirigid linker FRRRF in scaffoldin showed the highest initial F6P production rate of 10.16 µM/min, which indicates that the linker's amino acid composition in scaffoldin may lead to significant changes in the spatial architecture of the TIM-FBPA complex and consequently affect the initial reaction rate. Precise linker length and flexibility allow an appropriate interdomain conformation to enable efficient cascade reactions. Collectively, our results showed that fine-tuning the initial reaction rate of enzyme complexes is an integrated systematic engineering, including adjusting the multienzyme architecture, linker length, and linker flexibility, which provides rational guidance for designing effective multienzyme complexes in the future.

8.
Sheng Wu Gong Cheng Xue Bao ; 35(10): 1870-1888, 2019 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-31668035

RESUMO

In vitro multi-enzyme molecular machines that follow the designed multi-enzyme pathways, require the rational optimization and adaptation of several purified or partially purified enzyme components, in order to convert certain substrates into target compounds in vitro in an efficient manner. This type of molecular machine is component-based and modularized, so that its design, assembly, and regulation processes are highly flexible. Recently, the advantages of in vitro multi-enzyme molecular machines on the precise control of reaction process and the enhancement of product yield have suggested their great application potential in biomanufacturing. Studies on in vitro multi-enzyme molecular machines have become an important branch of synthetic biology, and are gaining increasing attentions. This article systematically reviews the enzyme component-/module-based construction strategy of in vitro multi-enzyme molecular machines, as well as the research progress on the improvement of compatibility among enzyme components/modules. The current challenges and future prospects of in vitro multi-enzyme molecular machines are also discussed.


Assuntos
Biotecnologia , Enzimas/química , Enzimas/metabolismo , Complexos Multienzimáticos/química , Complexos Multienzimáticos/metabolismo , Biologia Sintética
9.
Biotechnol Biofuels ; 12: 267, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31737096

RESUMO

Background: Cellulosic biomass, the earth's most abundant renewable resource, can be used as substrates for biomanufacturing biofuels or biochemicals via in vitro synthetic enzymatic biosystems in which the first step is the enzymatic phosphorolysis of cellodextrin to glucose 1-phosphate (G1P) by cellodextrin phosphorylase (CDP). However, almost all the CDPs prefer cellodextrin synthesis to phosphorolysis, resulting in the low reaction rate of cellodextrin phosphorolysis for biomanufacturing. Results: To increase the reaction rate of cellodextrin phosphorolysis, synthetic enzyme complexes containing CDP and phosphoglucomutase (PGM) were constructed to convert G1P to glucose 6-phosphate (G6P) rapidly, which is an important intermediate for biomanufacturing. Four self-assembled synthetic enzyme complexes were constructed with different spatial organizations based on the high-affinity and high-specific interaction between cohesins and dockerins from natural cellulosomes. Thus, the CDP-PGM enzyme complex with the highest enhancement of initial reaction rate was integrated into an in vitro synthetic enzymatic biosystem for generating bioelectricity from cellodextrin. The in vitro biosystem containing the best CDP-PGM enzyme complex exhibited a much higher current density (3.35-fold) and power density (2.14-fold) than its counterpart biosystem containing free CDP and PGM mixture. Conclusions: Hereby, we first reported bioelectricity generation from cellulosic biomass via in vitro synthetic enzymatic biosystems. This work provided a strategy of how to link non-energetically favorable reaction (cellodextrin phosphorolysis) and energetically favorable reaction (G1P to G6P) together to circumvent unfavorable reaction equilibrium and shed light on improving the reaction efficiency of in vitro synthetic enzymatic biosystems through the construction of synthetic enzyme complexes.

10.
Sci Rep ; 9(1): 13226, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519957

RESUMO

Though varying in nature, all waves share traits in a way that they all follow the superposition principle while also experiencing attenuation as they propagate in space. And thus it is more than common that a comprehensive investigation of one type of wave leads to a discovery that can be extended to all kinds of waves in other fields of research. In the field of magnetism, the wave of interest corresponds to the spin wave (SW). Specifically, there has been a push to use SWs as the next information carriers similar to how electromagnetic waves are used in photonics. At present, the biggest impediment in making SW-based device to be widely adapted is the fact that the SW experiences large attenuation due to the large damping constant. Here, we developed a method to find the SW eigenmodes and show that their respective eigen damping constants can be 40% smaller than the typical material damping constant. From a bigger perspective, this finding means that the attenuation of SW and also other types of waves in general is no more constrained by the material parameters, and it can be controlled by the shape of the waves instead.

11.
Plant Sci ; 288: 110219, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31521216

RESUMO

The 14-3-3 proteins are a family of highly conserved phosphoserine-binding proteins that participate in the regulation of diverse physiological and developmental processes. In this research, twenty 14-3-3 genes in apples, which contained a highly conserved 14-3-3 domain, were identified and divided into two subgroups. Among them, MdGRF11 was further cloned and investigated. qRT-PCR analyses and GUS staining show that MdGRF11 is expressed in various organs and tissues with the highest expression levels found in the fruit. MdGRF11 was upregulated by polyethylene glycol 6000 (PEG 6000), NaCl, abscisic acid (ABA) and low temperature (4 °C) treatments. MdGRF11-overexpressing transgenic Arabidopsis and apple calli exhibited reduced sensitivity to salt and PEG 6000 treatments. Moreover, the ectopic expression of MdGRF11 improved the tolerance of transgenic tobacco to salt and drought stresses, which grew longer roots, underwent more growth, and presented higher chlorophyll levels than the wild-type control under salt and drought stress conditions. Furthermore, MdGRF11 expression remarkably reduced electrolyte leakage, malondialdehyde content levels, H2O2 and O2- accumulation under salt and drought stress conditions, which relied on the regulation of ROS-scavenging signaling to reduce oxidative damage of cells after salt and drought stress treatment. MdGRF11 also enhanced tolerance to stress by upregulating expression levels of ROS-scavenging and stress-related genes, especially improving responses to drought stress by modifying the water loss rates and stomatal aperture. Moreover, MdGRF11 could interact with MdAREB/ABF transcription factors through yeast two hybrid analyses. In conclusion, our results indicate that MdGRF11 acts as a positive regulator of salt and drought stress responses through regulating ROS scavenging and other signaling systems.


Assuntos
Proteínas 14-3-3/genética , Secas , Regulação da Expressão Gênica de Plantas , Malus/genética , Proteínas de Plantas/genética , Tolerância ao Sal/genética , Proteínas 14-3-3/metabolismo , Ácido Abscísico/administração & dosagem , Temperatura Baixa , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/fisiologia , Malus/efeitos dos fármacos , Malus/fisiologia , Reguladores de Crescimento de Planta , Proteínas de Plantas/metabolismo , Polietilenoglicóis/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Cloreto de Sódio/administração & dosagem
12.
Biotechnol J ; : e1900191, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31487423

RESUMO

Scyllo-inositol (SI), a stereoisomer of inositol, is regarded as a promising therapeutic agent for Alzheimer's disease. Here, an in vitro cofactor-balance biotransformation for the production of SI from myo-inositol (MI) by thermophilic myo-inositol 2-dehydrogenase (IDH) and scyllo-inositol 2-dehydrogenase (SIDH) is presented. These two enzymes (i.e., IDH and SIDH from Geobacillus kaustophilus) are co-expressed in Escherichia coli BL21(DE3), and E. coli cells containing the two enzymes are permeabilized by heat treatment as whole-cell catalysts to convert MI to SI. After condition optimizations about permeabilized temperature, reaction temperature, and initial MI concentration, about 82 g L-1 of SI is produced from 250 g L-1 of MI within 24 h without any cofactor supplementation. This final titer of SI produced is the highest to the authors' limited knowledge. This study provides a promising method for the large-scale industrial production of SI.

13.
Chin Med J (Engl) ; 132(18): 2150-2156, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31490268

RESUMO

BACKGROUND: The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran. METHODS: A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed. RESULTS: During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 10/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99-1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 10/L. For leukocyte counts < 6.75 × 10/L, the HR (95% CI) was 0.88 (0.69-1.13), and for leukocyte counts ≥ 6.75 × 10/L, the HR (95% CI) was 1.28 (1.09-1.51). CONCLUSION: This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran. CLINICAL TRIAL REGISTRATION: NCT02414035, https://clinicaltrials.gov.

14.
BMC Plant Biol ; 19(1): 362, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31426743

RESUMO

BACKGROUND: The MYB transcription factor family is one of the largest transcriptional factor families in plants and plays a multifaceted role in plant growth and development. However, MYB transcription factors involved in pathogen resistance in apple remain poorly understood. RESULTS: We identified a new MYB family member from apple, and named it MdMYB30. MdMYB30 was localized to the nucleus, and was highly expressed in young apple leaves. Transcription of MdMYB30 was induced by abiotic stressors, such as polyethylene glycol and abscisic acid. Scanning electron microscopy and gas chromatograph-mass spectrometry analyses demonstrated that ectopically expressing MdMYB30 in Arabidopsis changed the wax content, the number of wax crystals, and the transcription of wax-related genes. MdMYB30 bound to the MdKCS1 promoter to activate its expression and regulate wax biosynthesis. MdMYB30 also contributed to plant surface properties and increased resistance to the bacterial strain Pst DC3000. Furthermore, a virus-based transformation in apple fruits and transgenic apple calli demonstrated that MdMYB30 increased resistance to Botryosphaeria dothidea. Our findings suggest that MdMYB30 plays a vital role in the accumulation of cuticular wax and enhances disease resistance in apple. CONCLUSIONS: MdMYB30 bound to the MdKCS1 gene promoter to activate its transcription and regulate cuticular wax content and composition, which influenced the surface properties and expression of pathogenesis-related genes to resistance against pathogens. MdMYB30 appears to be a crucial element in the formation of the plant cuticle and confers apple with a tolerance to pathogens.


Assuntos
Ascomicetos/fisiologia , Resistência à Doença , Malus/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Ceras/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/fisiologia , Expressão Ectópica do Gene , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno , Malus/metabolismo , Malus/microbiologia , Doenças das Plantas/microbiologia , Epiderme Vegetal/genética , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , RNA de Plantas/análise , Alinhamento de Sequência , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
15.
Mol Plant Microbe Interact ; 32(10): 1391-1401, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31408392

RESUMO

Salicylic acid (SA) is closely related to disease resistance of plants. WRKY transcription factors have been linked to the growth and development of plants, especially under stress conditions. However, the regulatory mechanism of WRKY proteins involved in SA production and disease resistance in apple is not clear. In this study, MdPBS3.1 responded to Botryosphaeria dothidea and enhanced resistance to B. dothidea. Electrophoretic mobility shift assays, yeast one-hybrid assays, and chromatin immunoprecipitation and quantitative PCR demonstrated that MdWRKY46 can directly bind to a W-box motif in the promoter of MdPBS3.1. Glucuronidase transactivation and luciferase analysis further showed that MdWRKY46 can activate the expression of MdPBS3.1. Finally, B. dothidea inoculation in transgenic apple calli and fruits revealed that MdWRKY46 improved resistance to B. dothidea by the transcriptional activation of MdPBS3.1. Viral vector-based transformation assays indicated that MdWRKY46 elevates SA content and transcription of SA-related genes, including MdPR1, MdPR5, and MdNPR1 in an MdPBS3.1-dependent way. These findings provide new insights into how MdWRKY46 regulates plant resistance to B. dothidea through the SA signaling pathway.


Assuntos
Ascomicetos , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Malus , Proteínas de Plantas , Transdução de Sinais , Ascomicetos/fisiologia , Resistência à Doença/genética , Malus/genética , Malus/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ácido Salicílico/metabolismo , Transdução de Sinais/genética
16.
Plant Mol Biol ; 101(1-2): 149-162, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267255

RESUMO

KEY MESSAGE: Here we describe that the regulation of MdWRKY31 on MdHIR4 in transcription and translation levels associated with disease in apple. The phytohormone salicylic acid (SA) is a main factor in apple (Malus domestica) production due to its function in disease resistance. WRKY transcription factors play a vital role in response to stress. An RNA-seq analysis was conducted with 'Royal Gala' seedlings treated with SA to identify the WRKY regulatory mechanism of disease resistance in apple. The analysis indicated that MdWRKY31 was induced. A quantitative real-time polymerase chain reaction (qPCR) analysis demonstrated that the expression of MdWRKY31 was induced by SA and flg22. Ectopic expression of MdWRKY31 in Arabidopsis and Nicotiana benthamiana increased the resistance to flg22 and Pseudomonas syringae tomato (Pst DC3000). A yeast two-hybrid screen was conducted to further analyze the function of MdWRKY31. As a result, hypersensitive-induced reaction (HIR) protein MdHIR4 interacted with MdWRKY31. Biomolecular fluorescence complementation, yeast two-hybrid, and pull-down assays demonstrated the interaction. In our previous study, MdHIR4 conferred decreased resistance to Botryosphaeria dothidea (B. dothidea). A viral vector-based transformation assay indicated that MdWRKY31 evaluated the transcription of SA-related genes, including MdPR1, MdPR5, and MdNPR1 in an MdHIR4-dependent way. A GUS analysis demonstrated that the w-box, particularly w-box2, of the MdHIR4 promoter played a major role in the responses to SA and B. dothidea. Electrophoretic mobility shift assays, yeast one-hybrid assay, and chromatin immunoprecipitation-qPCR demonstrated that MdWRKY31 directly bound to the w-box2 motif in the MdHIR4 promoter. GUS staining activity and a protein intensity analysis further showed that MdWRKY31 repressed MdHIR4 expression. Taken together, our findings reveal that MdWRKY31 regulated plant resistance to B. dothidea through the SA signaling pathway by interacting with MdHIR4.


Assuntos
Resistência à Doença , Malus/genética , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/metabolismo , Ácido Salicílico/farmacologia , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Ascomicetos/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Frutas/genética , Frutas/imunologia , Frutas/microbiologia , Regulação da Expressão Gênica de Plantas , Genes Reporter , Malus/imunologia , Malus/microbiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Regiões Promotoras Genéticas/genética , Pseudomonas syringae/fisiologia , Plântula/genética , Plântula/imunologia , Plântula/microbiologia , Transdução de Sinais , Tabaco/genética , Tabaco/imunologia , Tabaco/microbiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido
18.
Appl Microbiol Biotechnol ; 103(15): 6129-6139, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31172205

RESUMO

Phosphatases, which catalyze the dephosphorylation of compounds containing phosphate groups, are important members of the haloacid dehalogenase (HAD)-like superfamily. Herein, a thermostable phosphatase encoded by an open reading frame of Trd_1070 from Thermomicrobium roseum was enzymologically characterized. This phosphatase showed promiscuous activity against more than ten sugar phosphates, with high specific activity toward ribose 5-phosphate, followed by ribulose 5-phosphate and fructose 6-phosphate. The half-life of Trd_1070 at 70 °C and pH 7.0 was about 14.2 h. Given that the catalytic efficiency of Trd_1070 on fructose 6-phosphate was 49-fold higher than that on glucose 6-phosphate, an in vitro synthetic biosystem containing alpha-glucan phosphorylase, phosphoglucomutase, phosphoglucose isomerase, and Trd_1070 was constructed for the production of fructose from maltodextrin by whole-cell catalysis, resulting in 21.6 g/L fructose with a ratio of fructose to glucose of approximately 2:1 from 50 g/L maltodextrin. This in vitro biosystem provides an alternative method to produce fructose with higher fructose content compared with the traditional production method using glucose isomerization. Further discovery and enzymologic characterization of phosphatases may promote further production of alternative monosaccharides through in vitro synthetic biosystems.


Assuntos
Chloroflexi/enzimologia , Frutose/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Polissacarídeos/metabolismo , Biotransformação , Estabilidade Enzimática/efeitos da radiação , Temperatura Alta , Monoéster Fosfórico Hidrolases/química , Monoéster Fosfórico Hidrolases/genética , Especificidade por Substrato
19.
Nat Mater ; 18(7): 703-708, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31160801

RESUMO

The exchange interaction governs static and dynamic magnetism. This fundamental interaction comes in two flavours-symmetric and antisymmetric. The symmetric interaction leads to ferro- and antiferromagnetism, and the antisymmetric interaction has attracted significant interest owing to its major role in promoting topologically non-trivial spin textures that promise fast, energy-efficient devices. So far, the antisymmetric exchange interaction has been found to be rather short ranged and limited to a single magnetic layer. Here we report a long-range antisymmetric interlayer exchange interaction in perpendicularly magnetized synthetic antiferromagnets with parallel and antiparallel magnetization alignments. Asymmetric hysteresis loops under an in-plane field reveal a unidirectional and chiral nature of this interaction, which results in canted magnetic structures. We explain our results by considering spin-orbit coupling combined with reduced symmetry in multilayers. Our discovery of a long-range chiral interaction provides an additional handle to engineer magnetic structures and could enable three-dimensional topological structures.

20.
Biotechnol Bioeng ; 116(10): 2710-2719, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31237686

RESUMO

(-)-vibo-Quercitol (VQ: 1L-1,2,4/3,5-cyclohexanepentol), a form of deoxyinositol, is an alternative chiral building block in the synthesis of bioactive compounds to control diabetes. In this study, an adenosine triphosphate-free in vitro synthetic enzymatic biosystem composed of five enzymes (including one enzyme for NADH regeneration) was constructed to produce VQ from maltodextrin in one-pot. After optimization of reaction conditions, 7.6 g/L VQ was produced from 10 g/L maltodextrin with a product yield (mol/mol) of 77%, and 25.3 g/L VQ with a purity of 87% was produced from 50 g/L maltodextrin through simple scaling up of this nonfermentative enzymatic biosystem. Therefore, this study provides an economical and environmentally friendly method for the envisioned quercitol biosynthesis.

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