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Dive into the research topics where João Roberto Oliveira do Nascimento is active.

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Featured researches published by João Roberto Oliveira do Nascimento.


Food Chemistry | 2003

Physico-chemical changes related to quality of five strawberry fruit cultivars during cool-storage

Beatriz Rosana Cordenunsi; João Roberto Oliveira do Nascimento; Franco Maria Lajolo

Abstract Several parameters related to strawberry quality, such as texture, anthocyanin content, titratable acidity, pH, total ascorbic acid, and total soluble sugars, were evaluated over a week of cool storage. The results indicated that low temperature used to increase strawberry shelf-life could also induce small changes in some of the quality parameters studied. However, the data revealed the importance of the cultivar in question since there were some contrasting responses among the cultivars. Also the initial values for some of the parameters were clearly different, indicating that the cultivar is the most important factor for determining post-harvest quality and extended shelf-life. Texture is an important parameter with regard to shelf-life but was not determined since the ‘Mazi’ cultivar had a high initial value for texture but no changes occurred over the storage period. However, it had the shortest shelf-life. Changes in anthocyanin content were highly dependent on the cultivar. Except for ‘Toyonoka,’ no marked changes were observed in titratable acids or pH. Ascorbic acid decreased by 50% in all cultivars. The profiles of soluble sugars were different among cultivars but, for all of them, sucrose disappeared on day 2 of storage.


Planta | 1997

Banana sucrose-phosphate synthase gene expression during fruit ripening

João Roberto Oliveira do Nascimento; Beatriz Rosana Cordenunsi; Franco Maria Lajolo; Marcos Alcocer

Abstract. A 952-base pair polymerase-chain-reaction product of sucrose-phosphate synthase (SPS) (EC 2.3.1.14) from banana (Musa acuminata cv. Nanicão) fruit was cloned and used to study expression of the enzyme during development and ripening. The deduced amino acid sequence shows that banana SPS has a high homology with the leaf, tap-root and bean enzymes from other species. Enzyme activity, and mRNA and protein levels point to an increase in SPS expression during ripening. The accumulation of sucrose was correlated to starch degradation and happened 4 d after SPS mRNA and activity had reached their maxima. These results indicate that access to substrate and transcriptional activation with increase in SPS expression might be important regulatory events of sweetening during banana fruit ripening.


Planta | 2001

Inhibition of β-amylase activity, starch degradation and sucrose formation by indole-3-acetic acid during banana ripening

Eduardo Purgatto; Franco Maria Lajolo; João Roberto Oliveira do Nascimento; Beatriz Rosana Cordenunsi

Abstract. In order to observe the effect of indole- 3-acetic acid (IAA) on carbohydrate metabolism, unripe banana (Musa acuminata AAA, cv. Nanicão) slices were infiltrated with the hormone and left to ripen under controlled conditions. The climacteric respiration burst was reduced by the action of IAA, and starch degradation and sucrose formation were delayed. Sucrose synthase (SuSy; EC 2.4.1.13) and sucrose-phosphate synthase (SPS; EC 2.4.1.14) activities and transcript levels were not affected, indicating that prevention of sucrose accumulation was not related to sucrose-metabolizing enzymes. Impairment of sucrose synthesis could be a consequence of lack of substrate, since starch degradation was inhibited. The increase in activity and transcript level of β-amylase was delayed, indicating that this enzyme could be important in starch-to-sucrose metabolism in bananas and that it might be, at least partially, controlled at the transcriptional level. This is the first report showing that IAA can delay starch degradation, possibly affecting the activity of hydrolytic enzymes such as β-amylase (EC 3.2.1.2).


Journal of Plant Physiology | 2002

The onset of starch degradation during banana ripening is concomitant to changes in the content of free and conjugated forms of indole-3-acetic acid

Eduardo Purgatto; João Roberto Oliveira do Nascimento; Franco Maria Lajolo; Beatriz Rosana Cordenunsi

Summary Banana ( Musa acuminata AAA cv. Nanicao) slices were infiltrated with mannitol (control) and mannitol plus indole-3-acetic acid (IAA); then, some important ripening parameters like starch degradation, synthesis of ethylene and respiration were monitored. The contents of free-IAA and conjugated forms of IAA (ester and amide) were analyzed, by GC-MS-SIM, throughout the ripening in both banana slices and whole bananas. The starch degradation of IAA-treated slices was delayed for several days, but there was no difference between control and IAA-treated slices in the ethylene and respiration profiles. On day zero after infiltration, free-IAA levels were 500-fold higher in IAA-treated slices than in the control slices, but within 72 hours they declined to values 15-fold higher than those in the control group, with concomitant increase in IAA-ester. Similar to the banana slices, the onset of starch degradation occurred in whole bananas only when the free-IAA concentration was about 4 ng/g FW. The results herein suggest that IAA levels play a role during banana ripening in events like starch degradation with the consequence of banana sweetening.


Journal of Proteomics | 2012

Proteomic analysis of papaya fruit ripening using 2DE-DIGE

Silvia Beserra Nogueira; Carlos Alberto Labate; Fabio C. Gozzo; Eduardo Jorge Pilau; Franco Maria Lajolo; João Roberto Oliveira do Nascimento

Papayas have a very short green life as a result of their rapid pulp softening as well as their susceptibility to physical injury and mold growth. The ripening-related changes take place very quickly, and there is a continued interest in the reduction of postharvest losses. Proteins have a central role in biological processes, and differential proteomics enables the discrimination of proteins affected during papaya ripening. A comparative analysis of the proteomes of climacteric and pre-climacteric papayas was performed using 2DE-DIGE. Third seven proteins corresponding to spots with significant differences in abundance during ripening were submitted to MS analysis, and 27 proteins were identified and classified into six main categories related to the metabolic changes occurring during ripening. Proteins from the cell wall (alpha-galactosidase and invertase), ethylene biosynthesis (methionine synthase), climacteric respiratory burst, stress response, synthesis of carotenoid precursors (hydroxymethylbutenyl 4-diphosphate synthase, GcpE), and chromoplast differentiation (fibrillin) were identified. There was some correspondence between the identified proteins and the data from previous transcript profiling of papaya fruit, but new, accumulated proteins were identified, which reinforces the importance of differential proteomics as a tool to investigate ripening and provides potentially useful information for maintaining fruit quality and minimizing postharvest losses.


Journal of Proteomics | 2012

2D-DIGE analysis of mango (Mangifera indica L.) fruit reveals major proteomic changes associated with ripening

Jonathan de Magalhães Andrade; Tatiana Torres Toledo; Silvia Beserra Nogueira; Beatriz Rosana Cordenunsi; Franco Maria Lajolo; João Roberto Oliveira do Nascimento

A comparative proteomic investigation between the pre-climacteric and climacteric mango fruits (cv. Keitt) was performed to identify protein species with variable abundance during ripening. Proteins were phenol-extracted from fruits, cyanine-dye-labeled, and separated on 2D gels at pH 4-7. Total spot count of about 373 proteins spots was detected in each gel and forty-seven were consistently different between pre-climacteric and climacteric fruits and were subjected to LC-MS/MS analysis. Functional classification revealed that protein species involved in carbon fixation and hormone biosynthesis decreased during ripening, whereas those related to catabolism and the stress-response, including oxidative stress and abiotic and pathogen defense factors, accumulated. In relation to fruit quality, protein species putatively involved in color development and pulp softening were also identified. This study on mango proteomics provides an overview of the biological processes that occur during ripening.


Plant Physiology and Biochemistry | 2009

Molecular cloning and characterization of a ripening-induced polygalacturonase related to papaya fruit softening

João Paulo Fabi; Beatriz Rosana Cordenunsi; Graham B. Seymour; Franco Maria Lajolo; João Roberto Oliveira do Nascimento

Pulp softening is one of the most remarkable changes during ripening of papaya (Carica papaya) fruit and it is a major cause for post-harvest losses. Although cell wall catabolism has a major influence on papaya fruit, quality information on the gene products involved in this process is limited. A full-length polygalacturonase cDNA (cpPG) was isolated from papaya pulp and used to study gene expression and enzyme activity during normal and ethylene-induced ripening and after exposure of the fruit to 1-MCP. Northern-blot analysis demonstrated that cpPG transcription was strongly induced during ripening and was highly ethylene-dependent. The accumulation of cpPG transcript was paralleled by enzyme activity, and inversely correlated to the pulp firmness. Preliminary in silico analysis of the cpPG genomic sequence revealed the occurrence of putative regulatory motifs in the promoter region that may help to explain the effects of plant hormones and non-abiotic stresses on papaya fruit firmness. This newly isolated cpPG is an important candidate for functional characterization and manipulation to control the process of pulp softening during papaya ripening.


PLOS ONE | 2014

Analysis of papaya cell wall-related genes during fruit ripening indicates a central role of polygalacturonases during pulp softening.

João Paulo Fabi; Sabrina Garcia Broetto; Sarah Lígia Garcia Leme da Silva; Silin Zhong; Franco Maria Lajolo; João Roberto Oliveira do Nascimento

Papaya (Carica papaya L.) is a climacteric fleshy fruit that undergoes dramatic changes during ripening, most noticeably a severe pulp softening. However, little is known regarding the genetics of the cell wall metabolism in papayas. The present work describes the identification and characterization of genes related to pulp softening. We used gene expression profiling to analyze the correlations and co-expression networks of cell wall-related genes, and the results suggest that papaya pulp softening is accomplished by the interactions of multiple glycoside hydrolases. The polygalacturonase cpPG1 appeared to play a central role in the network and was further studied. The transient expression of cpPG1 in papaya results in pulp softening and leaf necrosis in the absence of ethylene action and confirms its role in papaya fruit ripening.


BMC Plant Biology | 2012

Analysis of ripening-related gene expression in papaya using an Arabidopsis-based microarray

João Paulo Fabi; Graham B. Seymour; Neil S. Graham; Martin R. Broadley; Sean T. May; Franco Maria Lajolo; Beatriz Rosana Cordenunsi; João Roberto Oliveira do Nascimento

BackgroundPapaya (Carica papaya L.) is a commercially important crop that produces climacteric fruits with a soft and sweet pulp that contain a wide range of health promoting phytochemicals. Despite its importance, little is known about transcriptional modifications during papaya fruit ripening and their control. In this study we report the analysis of ripe papaya transcriptome by using a cross-species (XSpecies) microarray technique based on the phylogenetic proximity between papaya and Arabidopsis thaliana.ResultsPapaya transcriptome analyses resulted in the identification of 414 ripening-related genes with some having their expression validated by qPCR. The transcription profile was compared with that from ripening tomato and grape. There were many similarities between papaya and tomato especially with respect to the expression of genes encoding proteins involved in primary metabolism, regulation of transcription, biotic and abiotic stress and cell wall metabolism. XSpecies microarray data indicated that transcription factors (TFs) of the MADS-box, NAC and AP2/ERF gene families were involved in the control of papaya ripening and revealed that cell wall-related gene expression in papaya had similarities to the expression profiles seen in Arabidopsis during hypocotyl development.ConclusionThe cross-species array experiment identified a ripening-related set of genes in papaya allowing the comparison of transcription control between papaya and other fruit bearing taxa during the ripening process.


Journal of the Science of Food and Agriculture | 2011

Ripening‐associated changes in the amounts of starch and non‐starch polysaccharides and their contributions to fruit softening in three banana cultivars

Tania Misuzu Shiga; Claudinéia Aparecida Soares; João Roberto Oliveira do Nascimento; Eduardo Purgatto; Franco Maria Lajolo; Beatriz Rosana Cordenunsi

BACKGROUND Fruit softening is generally attributed to cell wall degradation in the majority of fruits. However, unripe bananas contain a large amount of starch, and different banana cultivars vary in the amount of starch remaining in ripe fruits. Since studies on changes in pulp firmness carried out with bananas are usually inconclusive, the cell wall carbohydrates and the levels of starch and soluble cell wall monosaccharides from the pulps of three banana cultivars were analysed at different ripening stages. RESULTS Softening of Nanicão and Mysore bananas seemed to be more closely related to starch levels than to cell wall changes. For the plantain Terra, cell wall polysaccharide solubilisation and starch degradation appeared to be the main contributors. CONCLUSION Banana softening is a consequence of starch degradation and the accumulation of soluble sugars in a cultivar-dependent manner. However, contributions from cell wall-related changes cannot be disregarded.

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