Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.311
Filtrar
1.
J Agric Food Chem ; 67(35): 9772-9781, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31398019

RESUMO

This study aims to investigate the response profiles of vitamin E and carotenoids on transcription and metabolic levels of sweet corn seedlings under temperature stress. The treated temperatures were set as 10 °C (low temperature, LT), 25 °C (control, CK), and 40 °C (high temperature, HT) for sweet corn seedlings. The gene expression profiles of vitamin E and carotenoids biosynthesis pathways were analyzed by real time quantitative polymerase chain reaction (RT-qPCR), and the composition profiles were analyzed by high performance liquid chromatography (HPLC). Results showed that vitamin E gradually accumulated in response to LT stress but was limited by HT stress. The increase of carotenoids was suppressed by LT stress whereas HT stress promoted it. The existing results elaborated the interactive and competitive relationships of vitamin E and carotenoids in sweet corn seedlings to respond to extreme temperature stress at transcriptional and metabolic levels. The present study would improve sweet corn temperature resilience with integrative knowledge in the future.


Assuntos
Carotenoides/metabolismo , Vitamina E/metabolismo , Zea mays/metabolismo , Carotenoides/análise , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plântula/química , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Estresse Fisiológico , Temperatura Ambiente , Vitamina E/análise , Zea mays/química , Zea mays/genética , Zea mays/crescimento & desenvolvimento
2.
BMC Plant Biol ; 19(1): 335, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370805

RESUMO

BACKGROUND: Drought is a serious causal factor of reduced crop yields than any other abiotic stresses. As one of the most widely distributed crops, maize plants frequently suffer from drought stress, which causes great losses in the final kernel yield. Drought stress response in plants showed tissue- and developmental stage-specific characteristics. RESULTS: In this study, the ears at the V9 stage, kernels and ear leaf at the 5DAP (days after pollination) stage of maize were used for morphological, physiological and comparative transcriptomics analysis to understand the different features of "sink" or "source" organs and the effects on kernel yield under drought stress conditions. The ABA-, NAC-mediate signaling pathway, osmotic protective substance synthesis and protein folding response were identified as common drought stress response in the three organs. Tissue-specific drought stress responses and the regulators were identified, they were highly correlated with growth, physiological adaptation and yield loss under drought stress. For ears, drought stress inhibited ear elongation, led to the abnormal differentiation of the paired spikelet, and auxin signaling involved in the regulation of cell division and growth and primordium development changes. In the kernels, reduced kernel size caused by drought stress was observed, and the obvious differences of auxin, BR and cytokine signaling transduction appeared, which indicated the modification in carbohydrate metabolism, cell differentiation and growth retardation. For the ear leaf, dramatically and synergistically reduced the expression of photosynthesis genes were observed when suffered from drought stress, the ABA- and NAC- mediate signaling pathway played important roles in the regulation of photosynthesis. CONCLUSIONS: Transcriptomic changes caused by drought were highly correlated with developmental and physiological adaptation, which was closely related to the final yield of maize, and a sketch of tissue- and developmental stage-specific responses to drought stress in maize was drafted.


Assuntos
Zea mays/fisiologia , Produção Agrícola , Desidratação , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/fisiologia , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
3.
BMC Plant Biol ; 19(1): 351, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31412785

RESUMO

BACKGROUND: Rubisco activase (RCA) regulates the activity of Rubisco and is a key enzyme of photosynthesis. RCA expression was widely reported to affect plant photosynthesis and crop yield, but the molecular basis of natural variation in RCA expression in a wide range of maize materials has not been fully elucidated. RESULTS: In this study, correlation analysis in approximately 200 maize inbred lines revealed a significantly positive correlation between the expression of maize RCA gene ZmRCAß and grain yield. A genome-wide association study revealed both cis-expression quantitative trait loci (cis-eQTLs) and trans-eQTLs underlying the expression of ZmRCAß, with the latter playing a more important role. Further allele mining and genetic transformation analysis showed that a 2-bp insertion and a 14-bp insertion in the promoter of ZmRCAß conferred increased gene expression. Because rice is reported to have higher RCA gene expression than does maize, we subsequently compared the genetic factors underlying RCA gene expression between maize and rice. The promoter activity of the rice RCA gene was shown to be stronger than that of the maize RCA gene, suggesting that replacing the maize RCA gene promoter with that of the rice RCA gene would improve the expression of RCA in maize. CONCLUSION: Our results revealed two DNA polymorphisms regulating maize RCA gene ZmRCAß expression, and the RCA gene promoter activity of rice was stronger than that of maize. This work increased understanding of the genetic mechanism that underlies RCA gene expression and identify new targets for both genetic engineering and selection for maize yield improvement.


Assuntos
Oryza/genética , Fotossíntese/genética , Proteínas de Plantas/genética , Zea mays/genética , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Oryza/metabolismo , Oryza/fisiologia , Folhas de Planta , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Regiões Promotoras Genéticas , Locos de Características Quantitativas , Ribulose-Bifosfato Carboxilase , Zea mays/metabolismo , Zea mays/fisiologia
4.
Food Chem ; 298: 125044, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260971

RESUMO

Fumonisin B1 (FB1) is a carcinogenic mycotoxin produced by Fusarium species contaminating maize. At present, fumonisin determination is performed using costly and demanding chromatography techniques or immunoassays. Recently, a molecularly imprinted polymer nanoparticles (nanoMIPs) - based assay (MINA) has been developed for FB1 detection. Herein, we have applied MINA for the determination of FB1 in naturally contaminated maize samples and results were compared with those obtained with ELISA and a reference HPLC method (AOAC No. 2001.04). The nanoMIPs as a recognition element mimicking antibodies used in ELISA were produced by solid phase synthesis and used in MINA for FB1 determination in 53 maize samples. As a result, 18 maize samples were contaminated with FB1 at levels higher than 0.25 mg/kg. Fumonisin concentrations from samples measured by MINA were well correlated with those using ELISA and HPLC. Therefore, MINA could be used as an alternative technique for FB1 determination in maize.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Fumonisinas/análise , Impressão Molecular , Nanopartículas/química , Polímeros/química , Zea mays/química , Cromatografia Líquida de Alta Pressão , Zea mays/metabolismo
5.
BMC Vet Res ; 15(1): 233, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286932

RESUMO

BACKGROUND: The increasing costs of feed has subsequently increased the costs of production of livestock, thereby decreasing the profit margin of this sector. The utilization of agro-industrial by-products has to some extent substitute some of the corn grains and soyabean meal, commonly used in animal feeds. In Malaysia, palm kernel cake (PKC) is a by-product of the oil palm industry and is frequently used to supply both crude protein (14-16% CP) and energy (11 MJ/kg) in ruminants. The energy and protein content are adequate for maintenance in the majority of ruminants. However, highly available energy supplementation is known to improve growth performance and protein deposition. This study was carried out to determine the effect on the quality of meat and fatty acid composition of the semitendinosus (ST), supraspinatus (SS), and longissimus lumborum (LL) muscles of Dorper lambs by including corn as an energy source in a basal diet of PKC urea-treated rice straw. RESULTS: The results show that the LL muscle-drip loss was greater in animals supplemented with 5% corn compared to the other groups. Higher pH values of SS and LL muscles were observed in animals supplemented with 5 and 10% corn. Furthermore, the L* value of ST muscle was increased in lambs fed on 5% corn while, reduced in those fed on 0% corn, but the a* and b* values were not significantly different in the treatment groups. The fatty acid composition of the SS muscles showed that lambs fed on 10% corn had higher levels of sum PUFA n-3 compared to those fed on 0% corn. The concentration of C18:1trans11 and CLA c12 t10 in ST muscle from the lambs fed on supplemented diets were higher than those of the controls. CONCLUSION: This study has concluded the supplementation of corn as a source of energy into a PKC urea-treated rice straw-based diet increased the PUFA concentrations of muscles as compared to control groups.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Dieta/veterinária , Ácidos Graxos/análise , Carne/normas , Músculo Esquelético/química , Oryza/química , Zea mays/metabolismo , Ração Animal/normas , Animais , Malásia , Músculo Esquelético/metabolismo , Ovinos , Ureia/química
6.
Food Chem ; 297: 124995, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253267

RESUMO

The possible interactions between α-zein and Ca2+ in nixtamalization process were analyzed from a multidisciplinary approach, considering the effect of these interactions on the thermal properties of the nixtamalized flour. SDS-PAGE under reducing and non-reducing conditions did not reveal differences between patterns of zeins from nixtamalized and control samples. However, analysis from affinity capillary electrophoresis indicated an increment in protein volume when calcium is added to zein extracted from nixtamalized flour. In addition, the binding constant for the zein-calcium interaction was calculated indicating a higher affinity for calcium by zein from nixtamalized samples. Molecular dynamics simulations indicated that the interaction α-zein-Ca2+ through C-ter was more favorable than Glu48. However, in excess of Ca2+ ions, each site could bind one calcium atom at the same time, confirming that aggregation of α-zein through calcium bridges is possible, expanding the technological applications of this protein.


Assuntos
Cálcio/química , Modelos Teóricos , Zeína/química , Sítios de Ligação , Cálcio/metabolismo , Culinária , Eletroforese em Gel de Poliacrilamida , Farinha/análise , Simulação de Dinâmica Molecular , Termodinâmica , Temperatura de Transição , Zea mays/metabolismo , Zeína/metabolismo
7.
Food Chem ; 297: 124988, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253285

RESUMO

Agaricus blazei, Auricularia fuscosuccinea and Pleurotus albidus mycelia were obtained in solid-state cultivation (SSC), using grains (brown rice, canjica corn and wheat) as raw material. Colonized grain flours were analysed for their nutritional, physical and physico-chemical characteristics and biological activity in vitro. Wheat flour with P. albidus showed higher values for protein (18.34 g/100 g), ergosterol (0.60 mg/g), mycelial biomass (183 mg/g) and total amino acids (58.34 mg/g). Corn flour with A. fuscosuccinea showed the highest total phenolic content (2.38 mg GAE/g), antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) (8.90 µmol TEAC/g) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (16.52 µmol TEAC/g) assay. Wheat flour with P. albidus were more effective at inhibiting of pancreatic lipase (74.5%) and of α-glucosidase (98.2%). In conclusion, grains colonized by macrofungi mycelia through SSC can enrich the nutritional value and the biological activity of the flours, which presents a potential for functional foods.


Assuntos
Agaricus/fisiologia , Farinha/análise , Valor Nutritivo , Pleurotus/fisiologia , Aminoácidos/química , Antioxidantes/química , Biomassa , Ergosterol/análise , Lipase/antagonistas & inibidores , Lipase/metabolismo , Oryza/metabolismo , Fenóis/análise , Triticum/metabolismo , Zea mays/metabolismo , alfa-Glucosidases/química , alfa-Glucosidases/metabolismo
8.
Food Chem ; 297: 124912, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253263

RESUMO

An anti-idiotypic nanobody-phage display-mediated immuno-polymerase chain reaction (PD-IPCR) method was developed for simultaneous quantitative detection of total aflatoxins and zearalenone in cereals. Two phages, displaying the variable domain of the heavy chain anti-idiotypic nanobody that binds aflatoxin- or zearalenone-specific monoclonal antibody (1C11 or 2D3), were used as competitors for corresponding analytes. Specific DNA sequences encoding anti-idiotypic nanobodies were used to design the primers for PCR amplification. The results indicated that detection limits for total aflatoxins and zearalenone in a sample were 0.03 and 0.09 ng mL-1, respectively. Recoveries of spiked aflatoxins and zearalenone were 80-118% and 76.7-111%, respectively. Validation results were in good agreement with the gold-standard high-performance liquid chromatography method. This report is the first to describe PD-IPCR for simultaneous quantitative detection of total aflatoxins and zearalenone in cereals.


Assuntos
Aflatoxinas/análise , Anticorpos Anti-Idiotípicos/imunologia , Imunoensaio/métodos , Zearalenona/análise , Aflatoxinas/imunologia , Anticorpos Anti-Idiotípicos/genética , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Oryza/química , Oryza/metabolismo , Biblioteca de Peptídeos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Anticorpos de Domínio Único/genética , Anticorpos de Domínio Único/imunologia , Zea mays/química , Zea mays/metabolismo , Zearalenona/imunologia
9.
Food Chem ; 297: 124879, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253268

RESUMO

This study determined the effects of phenolic extracts from grape pomace and sorghum bran, reaction time and washing with aqueous ethanol on the pasting, flow, thermal and molecular properties of maize starch. The starch modification was carried out under alkaline conditions. The phenolic extracts increased the peak viscosity of the starch. Reaction time had no significant effect on starch properties. Washing with aqueous ethanol significantly increased the peak, final, and setback viscosities of the phenolic modified maize starches. DSC of phenolic modified starches showed higher enthalpy (ΔH) before and after washing with aqueous ethanol in comparison with starch without phenolic extract. FTIR spectra suggested the possible formation of hydrogen and ether (covalent) bonds between starch and phenolic compounds. It can be concluded that the pasting, flow and thermal properties of maize starch can be modified with phenolic extract under alkaline conditions to produce "clean label" starch-phenolic complex.


Assuntos
Fenóis/química , Extratos Vegetais/química , Sorghum/química , Amido/química , Vitis/química , Zea mays/metabolismo , Liofilização , Concentração de Íons de Hidrogênio , Sorghum/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/análise , Temperatura Ambiente , Termodinâmica , Viscosidade , Vitis/metabolismo
10.
Food Chem ; 297: 124931, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253328

RESUMO

Enzyme hydrolysis of corn gluten meal (CGM) is a promising process to prepare oligopeptides with high Fischer ratios (HFOPs). However, the relationship between Fischer ratios and enzyme hydrolysis approaches remains poorly understood. In this study, peptidomes of varying corn protein hydrolysates (CPHs) before and after activated carbon adsorption were profiled and analyzed according to sequence composition and chain length. Fischer ratios of HFOPs depended on sequences in CPHs by differing enzyme hydrolysis approaches, especially branched-chain amino acid (BCAA)-aromatic amino acid (AAA)-containing-oligopeptides. Activated carbon adsorption increased BCAA-containing-oligopeptide contents and decreased oligopeptide contents including AAAs, preferring BCAA-AAA-containing-oligopeptides with long chain length. Employing a three-enzyme hydrolysis approach, HFOPs were obtained with a yield of 49%, comprising 90% of dipeptides and tripeptides and possessing additional bioactivities. This work revealed the mechanism of HFOP production depending on the release and selective removal of oligopeptides and confirmed CGM was a promising alternative for value-added HFOP production.


Assuntos
Glutens/metabolismo , Oligopeptídeos/química , Zea mays/metabolismo , Adsorção , Aminoácidos Aromáticos/química , Aminoácidos de Cadeia Ramificada/química , Carbono/química , Cromatografia Líquida de Alta Pressão , Hidrólise , Peso Molecular , Oligopeptídeos/metabolismo , Peptídeo Hidrolases/metabolismo , Espectrometria de Massas em Tandem
11.
J Agric Food Chem ; 67(25): 7082-7086, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31199642

RESUMO

Vitamins are important nutrients for many fermentations, but they are generally costly. Agricultural lignocellulose biomass contains considerable amounts of vitamin B compounds, but these water-soluble vitamins are easily lost into wastewater discharge during pretreatment or detoxification of lignocellulose in biorefinery processes. Here, we showed that the dry acid pretreatment and biodetoxification process allowed the preservation of significant amounts of vitamin B, which promoted l-lactic acid fermentation efficiency significantly. Supplementation with specific vitamin B compounds, VB3 and VB5, into corn stover hydrolysate led to further increases of cellulosic l-lactic acid yield and fermentation rates. This study provided a new solution for the enhancement of biorefinery fermentation efficiency by using vitamin B compounds in lignocellulose biomass.


Assuntos
Ácido Láctico/metabolismo , Lignina/metabolismo , Pediococcus acidilactici/metabolismo , Complexo Vitamínico B/metabolismo , Fermentação , Hidrólise , Lignina/química , Pediococcus acidilactici/crescimento & desenvolvimento , Caules de Planta/química , Caules de Planta/metabolismo , Caules de Planta/microbiologia , Resíduos/análise , Zea mays/química , Zea mays/metabolismo , Zea mays/microbiologia
12.
J Agric Food Chem ; 67(25): 7050-7059, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31240932

RESUMO

This work aimed to investigate the effect of selenium (Se) and irrigation on the grain yield, on the forms of Se, phenols, and carotenes, and on some antioxidant activities of maize ( Zea mays L.) grains. To reach this goal, a 2 year experiment was undertaken. Maize was fertigated with sodium selenite at the rate of 200 g of Se ha-1 and grown under two water regimes. While the irrigation did not show a clear effect on the selected parameters, Se fertigation increased the contents of inorganic and organic Se forms, xanthophyll, and salicylic acid. Furthermore, while Se fertigation decreased the hydroxycinnamic acid content, generally higher antioxidant activities were found in Se-treated grains than in the control. These findings suggest that Se fertigation increases most of the nutraceutical values of maize grains, which therefore might improve human and livestock health and could increase the maize grain shelf life and its byproducts.


Assuntos
Antioxidantes/análise , Biofortificação/métodos , Suplementos Nutricionais/análise , Selenito de Sódio/metabolismo , Água/análise , Zea mays/química , Irrigação Agrícola , Antioxidantes/metabolismo , Alimentos Fortificados/análise , Sementes/química , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Selenito de Sódio/análise , Solo/química , Água/metabolismo , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
13.
Food Chem ; 296: 116-122, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202295

RESUMO

Oca (Oxalis tuberosa) is an underutilized species and represents a novel starch source. Composition and structure of starches from tubers of two commercial oca varieties grown in New Zealand were compared to those of normal maize and potato starches. The phosphorus content of oca starch was ∼60% of that of potato starch. The amylose content of oca starch (∼21%) was lower than that of maize and potato starches (concanavalin A precipitation method). The fine structure of oca amylopectin was much more similar to that of potato amylopectin than to that of maize amylopectin. Oca amylopectin had a shorter internal chain length and less fingerprint B-chains than potato amylopectin. The two oca starches were structurally and compositionally similar. Oca starch granules had a volume moment mean size of 34.5 µm and B-type polymorph. Comparative analysis suggested that oca starch has the potential to be developed as a novel starch source.


Assuntos
Oxalidaceae/metabolismo , Solanum tuberosum/metabolismo , Amido/química , Zea mays/metabolismo , Amilopectina/análise , Amilose/análise , Cromatografia Líquida de Alta Pressão , Microscopia Eletrônica de Varredura , Nova Zelândia , Fósforo/análise , Difração de Raios X
14.
J Chem Ecol ; 45(7): 598-609, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218595

RESUMO

Insect herbivory induces plant defense responses that are often modulated by components in insect saliva, oral secretions or regurgitant, frass, or oviposition fluids. These secretions contain proteins and small molecules that act as elicitors or effectors of plant defenses. Several non-protein elicitors have been identified from insect oral secretions, whereas studies of insect saliva have focused mainly on protein identification. Yet, insect saliva may also contain non-protein molecules that could activate defense responses in plants. The goal of this study was to identify non-protein plant defense elicitors present in insect saliva. We used the fall armyworm (FAW), Spodoptera frugiperda and its host plants tomato, maize, and rice as a model system. We tested the effect of protein-digested saliva or non-protein components on herbivore-induced defense responses in maize, rice and tomato. We identified phytohormones in FAW saliva using high performance liquid chromatography coupled with mass spectrometry. The results of this study show that non-protein components in FAW saliva modulated defense responses in different plant species. The saliva of this insect contains benzoic acid, and the phytohormones jasmonic acid, salicylic acid, and abscisic acid at concentrations of <5 ng per µl of saliva. Plant treatment with similar phytohormone quantities detected in FAW saliva upregulated the expression of a maize proteinase inhibitor gene in maize, and down-regulated late herbivore-induced defenses in tomato plants. We conclude that FAW saliva is a complex fluid that, in addition to known enzymatic plant defense elicitors, contains phytohormones and other small molecules.


Assuntos
Reguladores de Crescimento de Planta/análise , Saliva/química , Zea mays/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Herbivoria , Larva/metabolismo , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/parasitologia , Espectrometria de Massas , Reguladores de Crescimento de Planta/farmacologia , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Saliva/metabolismo , Spodoptera/crescimento & desenvolvimento , Zea mays/parasitologia
15.
Syst Appl Microbiol ; 42(4): 517-525, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31176475

RESUMO

Plant roots are inhabited by a large diversity of microbes, some of which are beneficial for the growth of plants and known as plant growth promoting rhizobacteria (PGPR). In this work, we designed a multispecies inoculum of PGPRs containing Rhizobium phaseoli, Sinorhizobium americanum and Azospirillum brasilense nitrogen-fixing strains and other plant-growth promoting bacteria such as Bacillus amyloliquefaciens and Methylobacterium extorquens. We evaluated the effect of this group of bacteria on the growth of one-month-old maize plants. The multispecies inoculum exerted a beneficial effect on maize plants that was greater than that obtained with single-bacteria. Using the same multispecies inoculant, acetylene reduction was recorded in 5-day-old roots indicating active nitrogen fixation by bacteria in maize. Azospirillum nitrogen fixation was lower than that obtained with the multispecies inoculum. We focused on the analysis of R. phaseoli gene expression in presence of other PGPRs. Many R. phaseoli up- regulated genes in roots in the presence of other bacteria are hypothetical, showing our poor knowledge of bacteria-bacteria interactions. Other genes indicated bacterial nutrient competition and R. phaseoli stress. Differentially expressed transcriptional regulators were identified that may be key in bacteria-bacteria interaction regulation. Additionally, gene expression was analyzed from Azospirillum but not from sinorhizobia and methylobacteria due to the low number of transcripts obtained from maize roots. The metatranscriptomic analysis from maize roots showed expression of Azospirillum nif genes in the presence of PGPR bacteria. Our hypothesis is that other bacteria stimulate Azospirillum capacity to fix nitrogen and this should be further explored.


Assuntos
Bactérias/genética , Interações Microbianas , Fixação de Nitrogênio/genética , Reguladores de Crescimento de Planta/genética , Zea mays/microbiologia , Bactérias/metabolismo , Proteínas de Bactérias/genética , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Microbiota , Reguladores de Crescimento de Planta/metabolismo , Reguladores de Crescimento de Planta/fisiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
16.
J Agric Food Chem ; 67(26): 7466-7474, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31184886

RESUMO

The ZMM28 protein encoded by the zmm28 gene is endogenous to maize. DP202216 maize was genetically modified to increase and extend expression of the zmm28 gene relative to native zmm28 gene expression, resulting in plants with enhanced grain yield potential. Evaluation of the history of safe use (HOSU) is one component of the safety assessment framework for a newly expressed protein in a GM crop. The deduced amino acid sequence of the introduced ZMM28 protein in DP202216 maize is identical to the ZMM28 protein in nonmodified conventional maize. The ZMM28 protein has also been found in selected varieties of sweet corn kernels, and closely related proteins are found in other commonly consumed food crops. Concentrations of the ZMM28 protein in event DP202216 maize, conventional maize, and sweet corn are reported. This information supports, in part, the evaluation of HOSU, which can be leveraged in the safety assessment of the ZMM28 protein. Additional studies will be considered in the food and feed safety assessment of the DP202216 maize event.


Assuntos
Proteínas de Plantas/química , Plantas Geneticamente Modificadas/química , Zea mays/química , Sequência de Aminoácidos , Qualidade de Produtos para o Consumidor , Inocuidade dos Alimentos , Alimentos Geneticamente Modificados , Humanos , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Alinhamento de Sequência , Zea mays/genética , Zea mays/metabolismo
17.
Carbohydr Polym ; 219: 172-180, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31151514

RESUMO

With respect of the partial molecular degradation of the starch polysaccharides, the impact of the acid-thinning process on the specific starch properties of two corn genotypes was investigated. A high amylose corn (HACS) and a waxy corn (WxCS) starch were hydrolyzed using HCl in the laboratory scale slurry process (40% w/w, 30 °C). The acid concentration (0.3, 0.6 and 0.9 M) as well as the hydrolysis time (4, 10 and 20 h) were graded systematically (experimental design) and the obtained modified starch genotypes characterized comprehensively. As revealed by scanning electron micoscopy (SEM), the supramolecular structure was preserved in general, and the carbohydrate solubilization was limited to about 2-3 %. Molecularly dispersed solutions were characterized by means of size exclusion chromatography-multi angle laser light scattering-differential refractive index detection (SEC-MALS-DRI). Both acid concentration and hydrolysis time reduced the molar mass (MM) of the starch [HACS: 4.4∙106 (native)…1.2∙106 g∙mol-1 (highest degree of degradation); WxCS: 49.7∙106 (native)…6.4∙106 g∙mol-1 (highest degree of degradation)], the amylose (AM) fraction as well as the amylopectin (AP) branch chain length systematically. Perceptible differences in dependence on starch variety were ascertained and discussed. The molecular properties of the investigated acid-thinned genotypes are selectively controllable with the hydrolysis process. The relationship between modification process, starch's molecular state, and resulting functional properties was examined in the second part of the study.


Assuntos
Amilopectina/química , Amilose/química , Amido/química , Zea mays/metabolismo , Análise de Variância , Cromatografia em Gel , Genótipo , Ácido Clorídrico/química , Hidrólise , Concentração Osmolar , Fatores de Tempo , Zea mays/genética
18.
Food Chem ; 295: 556-562, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174795

RESUMO

Hydroxypropyl (HP) starches are used as thickeners and stabilizers in foods. The properties of the etherified starches are dependent on the degree of hydroxypropylation. The objective of this study was to develop an improved acid hydrolysis method to degrade and solubilize HP starches for determining HP content in modified starches by 1H NMR. The effects of acid (DCl) concentration and temperature on hydrolysis and solubilization of hydroxypropylated starches were examined. The optimal conditions proposed to hydrolyze HP starches were 10% starch solid content, 3.5% (wt%) DCl in D2O as the solvent, sodium acetate as an internal standard, and heating at 90 °C for 1 h. Optionally, 6% (v/v) TFA-d may be added as the water-peak shifting reagent. Six hydroxypropylated starches and two cross-linked and hydroxypropylated starches were hydrolyzed with this improved acid method, and the results of the HP content were in agreement with those from an enzyme-catalyzed method.


Assuntos
Espectroscopia de Ressonância Magnética , Amido/química , Ácido Clorídrico/química , Hidrólise , Solubilidade , Temperatura Ambiente , Água/química , Zea mays/metabolismo
19.
Plant Cell Physiol ; 60(8): 1734-1746, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31076755

RESUMO

Pentatricopeptide repeat (PPR) proteins play crucial roles in intron splicing, which is important for RNA maturation. Identification of novel PPR protein with the function of intron splicing would help to understand the RNA splicing mechanism. In this study, we identified the maize empty pericarp602 (emp602) mutants, the mature kernels of which showed empty pericarp phenotype. We cloned the Emp602 gene from emp602 mutants and revealed that Emp602 encodes a mitochondrial-localized P-type PPR protein. We further revealed that Emp602 is specific for the cis-splicing of mitochondrial Nad4 intron 1 and intron 3, and mutation of Emp602 led to the loss of mature Nad4 transcripts. The loss of function of Emp602 nearly damaged the assembly and accumulation of complex I and arrested mitochondria formation, which arrested the seed development. The failed assembly of complex I triggers significant upregulation of Aox expression in emp602 mutants. Transcriptome analysis showed that the expression of mitochondrial-related genes, e.g. the genes associated with mitochondrial inner membrane presequence translocase complex and electron carrier activity, were extensively upregulated in emp602 mutant. These results demonstrate that EMP602 functions in the splicing of Nad4 intron 1 and intron 3, and the loss of function of Emp602 arrested maize seed development by disrupting the mitochondria complex I assembly.


Assuntos
Sementes/metabolismo , Zea mays/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Íntrons/genética , Íntrons/fisiologia , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo , Processamento de RNA/genética , Processamento de RNA/fisiologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Zea mays/genética , Zea mays/crescimento & desenvolvimento
20.
J Dairy Sci ; 102(7): 6235-6241, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31079907

RESUMO

The purpose of this study was to optimize the conditions of a previously proposed enzymatic method used to estimate in situ undigested neutral detergent fiber (uNDF). We used a multi-step enzymatic approach, in which samples were first solubilized in NaOH solutions as a preincubation (PreInc) phase. After rinsing, samples were incubated (24 h at 39°C) in a buffered solution (pH 6) containing hemicellulase, cellulase, and Viscozyme L enzymes (Sigma-Aldrich s.r.l., Milan, Italy), followed by incubation (24 h at 39°C) in a buffered solution (pH 5) containing xylanase. Two sets of experiments were performed: a calibration trial (that tested different PreInc conditions on 9 selected forages) and a validation trial (that verified the results by testing multiple samples of 6 different forage types and a group of fibrous by-products). In the calibration trial, samples (300 mg in Ankom F57 filter bags; Ankom Technology Corp., Fairport, NY) were preincubated at 39°C in a 0.1 M NaOH solution for 90, 180, or 240 min, or in 0.2, 0.5, 1.0, or 2.0 M NaOH solution for 90 min. The results indicated that the best PreInc method, in terms of intra-laboratory repeatability and estimation of reference in situ values, was 90 min in a 0.2 M NaOH solution. Thus, we used this PreInc condition to determine enzymatic uNDF of 257 samples in the validation trial. Although the selected method generally had good accuracy in predicting in situ uNDF, inconsistencies were noted for certain forage types. Overall, when enzymatic uNDF was used to predict the in situ uNDF of all samples, the regression was satisfactory (intercept = 7.098, slope = 0.920, R2 = 0.73). The regression models developed for alfalfa hays, corn silages, and small grain silages had also acceptable regression performances and mean square error of prediction (MSEP) values, and the main sources of MSEP variation were error due to incomplete (co)variation and random error. Even when R2 values were >0.70, the MSEP value of the regression model for grass hays was 149.55, and that for nonforage fibrous feeds was 155.16. Although enzymatic uNDF partially overestimated the in situ uNDF, particularly in grass silages, the proposed procedure seems to be promising for accurately predicting in situ uNDF, because it generally had good repeatability and provided satisfactory estimates of in situ uNDF.


Assuntos
Ração Animal/análise , Bovinos/metabolismo , Fibras na Dieta/análise , Fibras na Dieta/metabolismo , Digestão , Animais , Celulase/metabolismo , Feminino , Glicosídeo Hidrolases/metabolismo , Itália , Medicago sativa/metabolismo , Complexos Multienzimáticos/metabolismo , Reprodutibilidade dos Testes , Rúmen , Silagem/análise , Zea mays/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA