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1.
Food Chem ; 366: 130592, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34293549

RESUMO

An exhaustive migration study of eight corks, made of ethylene-vinyl acetate, was carried out to identify any non-volatile and volatile compounds using an untargeted approach. The challenge associated with the structural elucidation of unknowns was undertaken using both ultra-high-performance liquid chromatography coupled to an ion-mobility separation quadrupole-time of flight mass spectrometer and gas chromatography mass spectrometry. A total of fifty compounds were observed to migrate from the corks, and among these additives such as antioxidants (Butyl 4-hydroxybenzoate, Irganox 1010, Irganox 1075, Irgafos 168 and BHT) or lubricants (EBO and octadecanamide, N,N'-1,2-ethanediylbis-) were identified. A high proportion (84%) of the detected compounds was non-intentionally added substances (NIAS), and included several cyclic oligomers with different chain sequences. NIAS, such as 2,6-bis(1,1-dimethylethyl)-4-ethyl and 7,9-ditert-butyl-1-oxaspiro[4.5]deca-6,9-diene-2,8-dione, break-down products, including hexa-, hepta- and nonadecanamide, N,N'-1,2-ethanediylbis-, and oxidation products were also identified. One cork was found to be unsuitable for use as a food contact material.


Assuntos
Contaminação de Alimentos , Embalagem de Alimentos , Cromatografia Líquida , Etilenos , Contaminação de Alimentos/análise , Cromatografia Gasosa-Espectrometria de Massas , Espectrometria de Massas , Compostos de Vinila
2.
Food Chem ; 371: 131050, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34537615

RESUMO

Vitamin B3, derived primarily from plant sources, is an essential nutrient for humans. Torreya grandis is rich in vitamin B3, however, the mechanism underlying the biosynthesis and regulation of vitamin B3 in T. grandis remains unclear. A systematic transcriptomic investigation was thus conducted to identify the gene expression pattern of vitamin B3 biosynthesis in 10 T. grandis cultivars. The findings suggest that biosynthesis occurs mainly via the aspartate pathway. Expression and correlation analyses indicate that aspartate oxidase (AOX) and quinolinate synthase (QS) may play important roles in vitamin B3 accumulation. Furthermore, co-expression network and ethephon treatments indicate that the ethylene response factor (ERF) may be involved in the regulation of vitamin B3 biosynthesis in T. grandis nuts. Our findings not only help to elucidate the biosynthesis of vitamin B3, but also provide valuable resource material for future genomic research and molecular-assisted breeding to develop genotypes with higher vitamin B3 levels.


Assuntos
Nozes , Taxaceae , Etilenos , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Humanos , Nozes/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Vitaminas
3.
Food Chem ; 372: 131320, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34653780

RESUMO

Epicuticular waxes are important natural compounds that influence cuticle properties and can protect fruit from factors that harm its external quality. We demonstrated that, at a dose that reduces postharvest citrus fruit quality loss (4 d 2 µL L-1), ethylene redirected epicuticular wax metabolism towards the synthesis of primary alcohols, mostly behenyl alcohol, by favouring the acyl-reduction pathway. This treatment also reduced the synthesis of terpenoids by redirecting the mevalonate pathway towards farnesol accumulation to the detriment of the accumulation of most triterpenoids, but not of their precursor squalene. Moreover, the 4 d ethylene treatment sharply increased the synthesis of docosane and lignoceric acid and lowered that of cerotic acid. Longer ethylene exposure (8 d) reversed some of these effects by lowering the contents of most alcohols, lignoceric acid and squalene, while increasing that of its derivative sitosterol. The 8 d ethylene treatment also increased farnesol and docosane contents.


Assuntos
Citrus , Etilenos , Frutas , Ceras
4.
Chemosphere ; 287(Pt 1): 131989, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34450366

RESUMO

Thermally enhanced bioremediation is a promising approach to shorten the bioremediation period of tetrachloroethene (PCE) and trichloroethene (TCE). To clarify the influence that temperature has on stepwise PCE dechlorination and associated microorganisms, this study conducted dechlorination experiments using contaminated soil and groundwater under five distinct temperature conditions (i.e., 15, 20, 25, 30, and 35 °C). PCE and TCE were dechlorinated most rapidly at 25-35 °C, whereas the preferable temperatures for the dechlorination of cis-1,2- dichloroethene (cis-1,2-DCE) and vinyl chloride (VC) were 25-30 °C and 25 °C, respectively. Microbial community analysis revealed that Sulfurospirillum and Geobacter may have a dominant contribution to the dechlorination of PCE to cis-1,2-DCE, whereas Dehalococcoides harboring VC reductase genes are likely major contributors to the dechlorination of cis-1,2-DCE and VC. These results suggest that temperature influences various microbial groups, including major dechlorinating microorganisms, resulting in the different extent of PCE dechlorination. In addition, the microbial community structure greatly changed after the onset of the experiment, whereas the temperature influence of 15-30 °C on the microbial community structure was minor; however, the microbial community was significantly impacted at 35 °C. Collectively, these results suggest that thermally enhanced anaerobic dechlorination at 25 °C is useful for successful dechlorination of chlorinated ethenes in a short period.


Assuntos
Tetracloroetileno , Tricloroetileno , Cloreto de Vinil , Etilenos , Temperatura
5.
Food Chem ; 368: 130819, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34411865

RESUMO

Squalene and ß-sitosterol are health-benefit compounds due to their nutritional and medicinal properties. It has been reported that the content of these bioactive compounds is relatively high in Torreya grandis nuts. However, it is not yet known what changes in squalene and ß-sitosterol accumulation occur during the special post-ripening process of T. grandis nuts and the effect of the well-known ripening hormone ethylene on the regulatory mechanism of their biosynthetic pathways. Thus, we performed transcriptome and metabolite analyses. The results showed that ethylene not only promoted the post-ripening process but also enhanced the accumulation of squalene by inducing gene expression in the mevalonate pathway. At the same time, ethylene treatment also promoted the accumulation of other sterols but inhibited gene expression in the ß-sitosterol biosynthesis pathway. In addition, co-expression and correlation analysis suggested a framework for the transcriptional regulation of squalene and ß-sitosterol biosynthesis genes under ethylene treatment.


Assuntos
Nozes , Taxaceae , Etilenos , Frutas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Sitosteroides , Esqualeno
6.
J Agric Food Chem ; 69(45): 13596-13607, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34739246

RESUMO

Using a combination of biochemical, transcriptomic, and physiological analyses, we elucidated the mechanisms of physical and chemical withering of tea shoots subjected to UV-C and ethylene treatments. UV-C irradiation (15 kJ m-2) initiated oxidation of catechins into theaflavins, increasing theaflavin-3-monogallate and theaflavin digallate by 5- and 13.2-4.4-fold, respectively, at the end of withering. Concomitantly, a rapid change to brown/red, an increase in electrolyte leakage, and the upregulation of peroxidases (viz. Px2, Px4, and Px6) and polyphenol oxidases (PPO-1) occurred. Exogenous ethylene significantly increased the metabolic rate (40%) and moisture loss (30%) compared to control during simulated withering (12 h at 25 °C) and upregulated transcripts associated with responses to dehydration and abiotic stress, such as those in the ethylene signaling pathway (viz. EIN4-like, EIN3-FBox1, and ERFs). Incorporating ethylene during withering could shorten the tea manufacturing process, while UV-C could enhance the accumulation of flavor-related compounds.


Assuntos
Biflavonoides , Camellia sinensis , Catequina , Antioxidantes , Biflavonoides/análise , Catequina/análise , Catecol Oxidase/genética , Etilenos , Chá
7.
Plant Sci ; 313: 111063, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34763857

RESUMO

Kiwifruit is known as 'the king of vitamin C' because of the high content of ascorbic acid (AsA) in the fruit. Deciphering the regulatory network and identification of the key regulators mediating AsA biosynthesis is vital for fruit nutrition and quality improvement. To date, however, the key transcription factors regulating AsA metabolism during kiwifruit developmental and ripening processes remains largely unknown. Here, we generated a putative transcriptional regulatory network mediating ascorbate metabolism by transcriptome co-expression analysis. Further studies identified an ethylene response factor AcERF91 from this regulatory network, which is highly co-expressed with a GDP-galactose phosphorylase encoding gene (AcGGP3) during fruit developmental and ripening processes. Through dual-luciferase reporter and yeast one-hybrid assays, it was shown that AcERF91 is able to bind and directly activate the activity of the AcGGP3 promoter. Furthermore, transient expression of AcERF91 in kiwifruit fruits resulted in a significant increase in AsA content and AcGGP3 transcript level, indicating a positive role of AcERF91 in controlling AsA accumulation via regulation of the expression of AcGGP3. Overall, our results provide a new insight into the regulation of AsA metabolism in kiwifruit.


Assuntos
Actinidia/genética , Actinidia/metabolismo , Ácido Ascórbico/metabolismo , Etilenos/metabolismo , Galactose/metabolismo , Guanosina Difosfato/metabolismo , Fosforilases/metabolismo , Ácido Ascórbico/genética , China , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Frutas/genética , Frutas/metabolismo , Galactose/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Guanosina Difosfato/genética , Fosforilases/genética
8.
Molecules ; 26(19)2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34641581

RESUMO

UV-Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K+-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes' electronic spectra data were further employed for calculating the formation constants (KCT), molar extinction coefficients (εCT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP-DDQ and AMFP-TCNE complexes in CHCl3. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP-TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP-DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.


Assuntos
Amifampridina/química , Benzoquinonas/química , Etilenos/química , Nitrilas/química , Fenômenos Químicos , Teoria da Densidade Funcional , Elétrons , Estrutura Molecular , Bloqueadores dos Canais de Potássio/química , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier
9.
BMC Genomics ; 22(1): 743, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34649525

RESUMO

BACKGROUND: Fruit ripening is an intricate developmental process driven by a highly coordinated action of complex hormonal networks. Ethylene is considered as the main phytohormone that regulates the ripening of climacteric fruits. Concomitantly, several ethylene-responsive transcription factors (TFs) are pivotal components of the regulatory network underlying fruit ripening. Calmodulin-binding transcription activator (CAMTA) is one such ethylene-induced TF implicated in various stress and plant developmental processes. RESULTS: Our comprehensive analysis of the CAMTA gene family in Durio zibethinus (durian, Dz) identified 10 CAMTAs with conserved domains. Phylogenetic analysis of DzCAMTAs, positioned DzCAMTA3 with its tomato ortholog that has already been validated for its role in the fruit ripening process through ethylene-mediated signaling. Furthermore, the transcriptome-wide analysis revealed DzCAMTA3 and DzCAMTA8 as the highest expressing durian CAMTA genes. These two DzCAMTAs possessed a distinct ripening-associated expression pattern during post-harvest ripening in Monthong, a durian cultivar native to Thailand. The expression profiling of DzCAMTA3 and DzCAMTA8 under natural ripening conditions and ethylene-induced/delayed ripening conditions substantiated their roles as ethylene-induced transcriptional activators of ripening. Similarly, auxin-suppressed expression of DzCAMTA3 and DzCAMTA8 confirmed their responsiveness to exogenous auxin treatment in a time-dependent manner. Accordingly, we propose that DzCAMTA3 and DzCAMTA8 synergistically crosstalk with ethylene during durian fruit ripening. In contrast, DzCAMTA3 and DzCAMTA8 antagonistically with auxin could affect the post-harvest ripening process in durian. Furthermore, DzCAMTA3 and DzCAMTA8 interacting genes contain significant CAMTA recognition motifs and regulated several pivotal fruit-ripening-associated pathways. CONCLUSION: Taken together, the present study contributes to an in-depth understanding of the structure and probable function of CAMTA genes in the post-harvest ripening of durian.


Assuntos
Bombacaceae , Bombacaceae/metabolismo , Calmodulina/genética , Etilenos , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética
10.
Nat Commun ; 12(1): 5832, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34611160

RESUMO

Maize ear size and kernel number differ among lines, however, little is known about the molecular basis of ear length and its impact on kernel number. Here, we characterize a quantitative trait locus, qEL7, to identify a maize gene controlling ear length, flower number and fertility. qEL7 encodes 1-aminocyclopropane-1- carboxylate oxidase2 (ACO2), a gene that functions in the final step of ethylene biosynthesis and is expressed in specific domains in developing inflorescences. Confirmation of qEL7 by gene editing of ZmACO2 leads to a reduction in ethylene production in developing ears, and promotes meristem and flower development, resulting in a ~13.4% increase in grain yield per ear in hybrids lines. Our findings suggest that ethylene serves as a key signal in inflorescence development, affecting spikelet number, floral fertility, ear length and kernel number, and also provide a tool to improve grain productivity by optimizing ethylene levels in maize or in other cereals.


Assuntos
Zea mays/metabolismo , Zea mays/fisiologia , Mapeamento Cromossômico , Grão Comestível/genética , Grão Comestível/metabolismo , Etilenos/metabolismo , Meristema/citologia , Meristema/metabolismo , Locos de Características Quantitativas/genética
11.
Ecotoxicol Environ Saf ; 226: 112844, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34619479

RESUMO

Nowadays, the applications of engineered nanoparticles (ENPs) have been significantly increased, thereby negatively affecting crop production and ultimately contaminating the food chain worldwide. Zinc oxide nanoparticles (ZnO NPs) induced oxidative stress has been clarified in previous studies. But until now, it has not been investigated that how ethylene mediates or participates in ZnO NPs-induced toxicity and related cellular ultrastructural changes in rice seedlings. Here, we reported that 500 mg/L of ZnO NPs reduced the fresh weight (54.75% and 55.64%) and dry weight (40.33% and 47.83%) in shoot and root respectively as compared to control. Furthermore, ZnO NPs (500 mg/L) reduced chlorophyll content (72% Chla, 70% Chlb), induced the stomatal closure and ultrastructural damages by causing oxidative stress in rice seedlings. These cellular damages were significantly increased by exogenous applications of ethylene biosynthesis precursor (ACC) in the presence of ZnO NPs. In contrary, ZnO NPs induced damages on the above-mentioned attributes were reversed through the exogenous supply of ethylene signaling and biosynthesis antagonists such as silver (Ag) and cobalt (Co) respectively. Interestingly, ZnO NPs accelerate ethylene biosynthesis by up-regulating the transcriptome of ethylene biosynthesis responsive genes. The antioxidant enzymes activities and related gene expressions were further increased in ethylene signaling and biosynthesis associated antagonists (Ag and Co) treated seedlings as compared to sole ZnO NPs treatments. In contrary, the above-reported attributes were further decreased by ACC together with ZnO NPs. In a nutshell, ethylene effectively contributes in ZnO NPs induced toxicity and causing ultrastructural and stomatal damage in rice seedlings. Such findings could have potential implications in producing genetic engineered crops, which will be able to tolerate nanoparticles toxicity in the environment.


Assuntos
Nanopartículas , Oryza , Óxido de Zinco , Etilenos , Nanopartículas/toxicidade , Oryza/genética , Estresse Oxidativo , Raízes de Plantas , Plântula , Óxido de Zinco/toxicidade
12.
Waste Manag ; 136: 184-194, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34689097

RESUMO

Postconsumer polyethylene terephthalate (PET) has potential applications in many areas of manufacturing, but contamination by hazardous polyvinyl chloride (PVC) in common waste streams can reduce its recyclable value. Separating collected PET-PVC mixtures before recycling remains very challenging because of the similar physicochemical properties of PET and PVC. Herein, we describe a novel flotation process with corona modification pretreatment to facilitate the separation of PET-PVC mixtures. Through water contact angle, surface free energy, X-ray photoelectron and FT-IR characterization, we found that polar hydroxyl groups can be more easily introduced on the PVC surface than on the PET surface induced by corona modification. This selective wetting can suppress the floatability of PVC, leading to the separation of PET as floating product. A reliable mechanism including two different hydrogen-abstraction pathways was established. Response surface methodology consisting of Plackett-Burman and Box-Behnken designs was adopted for optimization of the combined process, and control parameters were solved based on high-quality prediction models, with fitting from significant variables and interactions. For physical or chemical circulation strategies with PET purity prioritization, the validated purity of the product reached 96.05% at a 626 W corona power, 5.42 m/min passing speed, 24.78 mg/L frother concentration and 286 L/h air flow rate. For the energy recuperation strategy with PET recovery prioritization, the factual recovery reached 98.08% under a 601 W corona power, 6.04 m/min passing speed, 27.55 mg/L frother concentration and 184 L/h air flow rate. The current work provides technological insights into the cleaner disposal of waste plastics.


Assuntos
Eliminação de Resíduos , Cloreto de Vinil , Etilenos , Ácidos Ftálicos , Plásticos , Polietilenotereftalatos , Cloreto de Polivinila , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Arch Microbiol ; 203(10): 6215-6229, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34609529

RESUMO

The endophytic fungus Phomopsis liquidambaris is characterized as a plant growth-promoting agent under salt stress, but its mechanism is unknown. Herein, 1-aminocyclopropane-1-carboxylate deaminase (ACCD) from the strain was confirmed that it had the ability of utilizing 1-aminocyclopropane-1-carboxylate as the sole nitrogen source. The full-length ACCD gene was 1152 bp, which encodes a mature protein of 384 amino acids with a molecular mass of 41.53 kDa. The ACCD activity was 3.9-fold in 3 mmol L-1 ACC by qRT-PCR under salt stress comparing with no salt tress. Ethylene production was increased to 34.55-70.60% and reduced the growth of rice by 23-69.73% under salt stress. Inoculation of P. liquidambaris increased root-shoot length, fresh and dry weight, and overall growth of stressed rice seedlings. ACC accumulation, ACC synthase and ACC oxidase activities increased in salt-treated rice seedlings, while they were significantly reduced when P. liquidambaris was inoculated into rice by qRT-PCR. It therefore can be concluded that P. liquidambaris can be used as a plant growth promoting fungus against salt stress and other biotic or abiotic stresses.


Assuntos
Oryza , Carbono-Carbono Liases , Etilenos , Phomopsis , Estresse Salino
14.
J Hazard Mater ; 416: 125928, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34489083

RESUMO

Plastic wastes are becoming the most common form of marine debris and present a growing global pollution problem. Here, we used a screening approach on hundreds of plastic waste-associated samples and discovered a marine bacterial community capable of efficiently colonizing and degrading both poly(ethylene terephthalate) (PET) and polyethylene (PE). Using absolute quantitative 16S rRNA sequencing and cultivation methods, we obtained corresponding abundance and purified cultures of three bacterial strains that mediated plastic degradation. We further performed numerous techniques to characterize the efficient degradation of PET and PE by the reconstituted bacterial community containing these three bacteria. Additionally, we used liquid chromatography-mass spectrometry to further demonstrate the degradation of PET and PE films by the reconstituted bacterial community. We conducted transcriptomic methods to investigate the plastic degradation process and potential degradation mechanisms mediated by our reconstituted bacterial community. Lastly, we overexpressed PE degradation enzymes based on transcriptomic results and verified their significant degradation effects on the PE films. Overall, our study establishes a stable marine bacterial community that efficiently degrades PET and PE and provides insights into plastic degradation pathways and their associated biological and mechanistic processes-paving the way for developing microbial products against plastic wastes.


Assuntos
Polietilenotereftalatos , Polietileno , Bactérias/genética , Biodegradação Ambiental , Etilenos , Ácidos Ftálicos , Plásticos , RNA Ribossômico 16S/genética
15.
BMC Plant Biol ; 21(1): 412, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34496757

RESUMO

BACKGROUND: Fusarium oxysporum f. sp. lycopersici (Fol) is a compendium of pathogenic and non-pathogenic fungal strains. Pathogenic strains may cause vascular wilt disease and produce considerable losses in commercial tomato plots. To gain insight into the molecular mechanisms mediating resistance to Fol in tomato, the aim of our study was to characterize the transcriptional response of three cultivars (CT1, CT2 and IAC391) to a pathogenic (Fol-pt) and a non-pathogenic (Fo-npt) strain of Fo. RESULTS: All cultivars exhibited differentially expressed genes in response to each strain of the fungus at 36 h post-inoculation. For the pathogenic strain, CT1 deployed an apparent active defense response that included upregulation of WRKY transcription factors, an extracellular chitinase, and terpenoid-related genes, among others. In IAC391, differentially expressed genes included upregulated but mostly downregulated genes. Upregulated genes mapped to ethylene regulation, pathogenesis regulation and transcription regulation, while downregulated genes potentially impacted defense responses, lipid transport and metal ion binding. Finally, CT2 exhibited mostly downregulated genes upon Fol-pt infection. This included genes involved in transcription regulation, defense responses, and metal ion binding. CONCLUSIONS: Results suggest that CT1 mounts a defense response against Fol-pt. IAC391 exhibits an intermediate phenotype whereby some defense response genes are activated, and others are suppressed. Finally, the transcriptional profile in the CT2 hints towards lower levels of resistance. Fo-npt also induced transcriptional changes in all cultivars, but to a lesser extent. Results of this study will support genetic breeding programs currently underway in the zone.


Assuntos
Fusarium/patogenicidade , Interações Hospedeiro-Patógeno/genética , Lycopersicon esculentum/genética , Lycopersicon esculentum/microbiologia , Proteínas de Plantas/genética , Cromossomos de Plantas , Colômbia , Resistência à Doença/genética , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Fatores de Transcrição/genética
16.
BMC Plant Biol ; 21(1): 411, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34496770

RESUMO

BACKGROUND: The phytohormone ethylene controls many processes in plant development and acts as a key signaling molecule in response to biotic and abiotic stresses: it is rapidly induced by flooding, wounding, drought, and pathogen attack as well as during abscission and fruit ripening. In kiwifruit (Actinidia spp.), fruit ripening is characterized by two distinct phases: an early phase of system-1 ethylene biosynthesis characterized by absence of autocatalytic ethylene, followed by a late burst of autocatalytic (system-2) ethylene accompanied by aroma production and further ripening. Progress has been made in understanding the transcriptional regulation of kiwifruit fruit ripening but the regulation of system-1 ethylene biosynthesis remains largely unknown. The aim of this work is to better understand the transcriptional regulation of both systems of ethylene biosynthesis in contrasting kiwifruit organs: fruit and leaves. RESULTS: A detailed molecular study in kiwifruit (A. chinensis) revealed that ethylene biosynthesis was regulated differently between leaf and fruit after mechanical wounding. In fruit, wound ethylene biosynthesis was accompanied by transcriptional increases in 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), ACC oxidase (ACO) and members of the NAC class of transcription factors (TFs). However, in kiwifruit leaves, wound-specific transcriptional increases were largely absent, despite a more rapid induction of ethylene production compared to fruit, suggesting that post-transcriptional control mechanisms in kiwifruit leaves are more important. One ACS member, AcACS1, appears to fulfil a dominant double role; controlling both fruit wound (system-1) and autocatalytic ripening (system-2) ethylene biosynthesis. In kiwifruit, transcriptional regulation of both system-1 and -2 ethylene in fruit appears to be controlled by temporal up-regulation of four NAC (NAM, ATAF1/2, CUC2) TFs (AcNAC1-4) that induce AcACS1 expression by directly binding to the AcACS1 promoter as shown using gel-shift (EMSA) and by activation of the AcACS1 promoter in planta as shown by gene activation assays combined with promoter deletion analysis. CONCLUSIONS: Our results indicate that in kiwifruit the NAC TFs AcNAC2-4 regulate both system-1 and -2 ethylene biosynthesis in fruit during wounding and ripening through control of AcACS1 expression levels but not in leaves where post-transcriptional/translational regulatory mechanisms may prevail.


Assuntos
Actinidia/genética , Etilenos/biossíntese , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Actinidia/metabolismo , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Liases/genética , Liases/metabolismo , Lycopersicon esculentum/genética , Filogenia , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas , Fatores de Transcrição/metabolismo
17.
ACS Appl Mater Interfaces ; 13(36): 43696-43707, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34470205

RESUMO

Graphene is a two-dimensional semiconducting material whose application for diagnostics has been a real game-changer in terms of sensitivity and response time, variables of paramount importance to stop the COVID-19 spreading. Nevertheless, strategies for the modification of docking recognition and antifouling elements to obtain covalent-like stability without the disruption of the graphene band structure are still needed. In this work, we conducted surface engineering of graphene through heterofunctional supramolecular-covalent scaffolds based on vinylsulfonated-polyamines (PA-VS). In these scaffolds, one side binds graphene through multivalent π-π interactions with pyrene groups, and the other side presents vinylsulfonated pending groups that can be used for covalent binding. The construction of PA-VS scaffolds was demonstrated by spectroscopic ellipsometry, Raman spectroscopy, and contact angle measurements. The covalent binding of -SH, -NH2, or -OH groups was confirmed, and it evidenced great chemical versatility. After field-effect studies, we found that the PA-VS-based scaffolds do not disrupt the semiconducting properties of graphene. Moreover, the scaffolds were covalently modified with poly(ethylene glycol) (PEG), which improved the resistance to nonspecific proteins by almost 7-fold compared to the widely used PEG-monopyrene approach. The attachment of recognition elements to PA-VS was optimized for concanavalin A (ConA), a model lectin with a high affinity to glycans. Lastly, the platform was implemented for the rapid, sensitive, and regenerable recognition of SARS-CoV-2 spike protein and human ferritin in lab-made samples. Those two are the target molecules of major importance for the rapid detection and monitoring of COVID-19-positive patients. For that purpose, monoclonal antibodies (mAbs) were bound to the scaffolds, resulting in a surface coverage of 436 ± 30 ng/cm2. KD affinity constants of 48.4 and 2.54 nM were obtained by surface plasmon resonance (SPR) spectroscopy for SARS-CoV-2 spike protein and human ferritin binding on these supramolecular scaffolds, respectively.


Assuntos
Biomarcadores/análise , COVID-19/diagnóstico , Grafite/química , Imunoensaio/métodos , Glicoproteína da Espícula de Coronavírus/análise , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Etilenos/química , Ferritinas/imunologia , Ferritinas/metabolismo , Humanos , Sistemas Automatizados de Assistência Junto ao Leito , Poliaminas/química , Polietilenoglicóis/química , Pirenos/química , Teoria Quântica , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Semicondutores , Glicoproteína da Espícula de Coronavírus/imunologia , Ácidos Sulfônicos/química , Ressonância de Plasmônio de Superfície
18.
Bioresour Technol ; 341: 125852, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34479144

RESUMO

Cyanobacterial research is impeded by the substantial discrepancies between laboratory studies and outdoor performances, despite successful demonstrations of genetically engineered strains for array of compounds. Therefore, evaluation of adaptive responses is necessary to achieve outdoor scale-up cultivation of cyanobacteria. Under current study, cyanobacterium Synechococcus elongatusPCC7942 engineered for ethylene biosynthesis, was gradually acclimatised, ensuring sustained and progressive transition from laboratory to outdoor conditions. Bubble size of 4.9 ± 0.2 mm and air-flow rate of 0.05 vvm in BG11 supplemented with 5 g/L bicarbonate giving mass transfer coefficient (KLa) of 10.48 h-1 yielded highest specific growth rate (0.24 h-1) with the transformants. At the 100 L photobioreactor scale, ethylene productivity of 1.5 mL.L-1.h-1 was achieved. A comprehensive investigation on photosynthetic responses of the transformants adapted to the outdoor conditions exhibited interesting photosynthetic electron transport regulations, involving antenna density modulation in response to diurnal and dynamic light transitions, indicating successful transition.


Assuntos
Synechococcus , Etilenos , Laboratórios , Fotobiorreatores , Fotossíntese , Synechococcus/genética
19.
Enzyme Microb Technol ; 150: 109868, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34489027

RESUMO

Poly(ethylene terephthalate) (PET) is a class of polyester plastic composed of terephthalic acid (TPA) and ethylene glycol (EG). The accumulation of large amount of PET waste has resulted in severe environmental and health problems. Microbial polyester hydrolases with the ability to degrade PET provide an economy- and environment-friendly approach for the treatment of PET waste. In recent years, many PET hydrolases have been discovered and characterized from various microorganisms and engineered for better performance under practical application conditions. Here, recent progress in the discovery, characterization, and enzymatic mechanism elucidation of PET hydrolases is firstly reviewed. Then, structure-guided protein engineering of PET hydrolases with increased enzymatic activities, expanded substrate specificity, as well as improved protein stability is summarized. In addition, strategies for efficient expression of recombinant PET hydrolases, including secretory expression and cell-surface display, are briefly introduced. This review is concluded with future perspectives in biodegradation and subsequent biotransformation of PET wastes to produce value-added compounds.


Assuntos
Ácidos Ftálicos , Polietilenotereftalatos , Etilenos , Hidrolases/genética
20.
BMC Plant Biol ; 21(1): 420, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34517831

RESUMO

BACKGROUND: Natural rubber (cis-1,4-polyioprene, NR) is an indispensable industrial raw material obtained from the Pará rubber tree (H. brasiliensis). Natural rubber cannot be replaced by synthetic rubber compounds because of the superior resilience, elasticity, abrasion resistance, efficient heat dispersion, and impact resistance of NR. In NR production, latex is harvested by periodical tapping of the trunk bark. Ethylene enhances and prolongs latex flow and latex regeneration. Ethephon, which is an ethylene-releasing compound, applied to the trunk before tapping usually results in a 1.5- to 2-fold increase in latex yield. However, intense mechanical damage to bark tissues by excessive tapping and/or over-stimulation with ethephon induces severe oxidative stress in laticifer cells, which often causes tapping panel dryness (TPD) syndrome. To enhance NR production without causing TPD, an improved understanding of the molecular mechanism of the ethylene response in the Pará rubber tree is required. Therefore, we investigated gene expression in response to ethephon treatment using Pará rubber tree seedlings as a model system. RESULTS: After ethephon treatment, 3270 genes showed significant differences in expression compared with the mock treatment. Genes associated with carotenoids, flavonoids, and abscisic acid biosynthesis were significantly upregulated by ethephon treatment, which might contribute to an increase in latex flow. Genes associated with secondary cell wall formation were downregulated, which might be because of the reduced sugar supply. Given that sucrose is an important molecule for NR production, a trade-off may arise between NR production and cell wall formation for plant growth and for wound healing at the tapping panel. CONCLUSIONS: Dynamic changes in gene expression occur specifically in response to ethephon treatment. Certain genes identified may potentially contribute to latex production or TPD suppression. These data provide valuable information to understand the mechanism of ethylene stimulation, and will contribute to improved management practices and/or molecular breeding to attain higher yields of latex from Pará rubber trees.


Assuntos
Etilenos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Hevea/genética , Hevea/metabolismo , Látex/metabolismo , Plântula/genética , Plântula/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Genes de Plantas , Indonésia
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