Campina Grande, Brazil
Campina Grande, Brazil

Time filter

Source Type

Bezerra C.A.,Catholic University of Brasília | Macedo L.L.P.,Catholic University of Brasília | Amorim T.M.L.,Federal University of Rio Grande do Norte | Santos V.O.,Federal University of Rio Grande do Norte | And 8 more authors.
Gene | Year: 2014

α-Amylases are common enzymes responsible for hydrolyzing starch. Insect-pests, whose larvae develop in seeds, rely obligatorily on α-amylase activity to digest starch, as their major food source. Considering the relevance of insect α-amylases and the natural α-amylase inhibitors present in seeds to protect from insect damage, we report here the molecular cloning and nucleotide sequence of the full-length AmyHha cDNA of the coffee berry borer, Hypothenemus hampei, a major insect-pest of coffee crops. The AmyHha sequence has 1879. bp, containing a 1458. bp open reading frame, which encodes a predicted protein with 485 amino acid residues, with a predicted molecular mass of 51.2. kDa. The deduced protein showed 55-79% identity to other insect α-amylases, including Anthonomus grandis, Ips typographus and Sitophilus oryzae α-amylases. In depth analysis revealed that the highly conserved three amino acid residues (Asp184, Glu220, and Asp285), which compose the catalytic site are also presented in AmyHha amylase. The AmyHha gene seems to be a single copy in the haploid genome and AmyHha transcription levels were found higher in L2 larvae and adult insects, both corresponding to major feeding phases. Modeling of the AmyHha predicted protein uncovered striking structural similarities to the Tenebrio molitor α-amylase also displaying the same amino acid residues involved in enzyme catalysis (Asp184, Glu220 and Asp285). Since AmyHha gene was mostly transcribed in the intestinal tract of H. hampei larvae, the cognate α-amylase could be considered a high valuable target to coffee bean insect control by biotechnological strategies. © 2014 The Authors.


PubMed | Agronomic Institute of Parana, University of Caldas, Catholic University of Brasília, French National Institute for Agricultural Research and 4 more.
Type: Journal Article | Journal: Gene | Year: 2014

-Amylases are common enzymes responsible for hydrolyzing starch. Insect-pests, whose larvae develop in seeds, rely obligatorily on -amylase activity to digest starch, as their major food source. Considering the relevance of insect -amylases and the natural -amylase inhibitors present in seeds to protect from insect damage, we report here the molecular cloning and nucleotide sequence of the full-length AmyHha cDNA of the coffee berry borer, Hypothenemus hampei, a major insect-pest of coffee crops. The AmyHha sequence has 1879 bp, containing a 1458 bp open reading frame, which encodes a predicted protein with 485 amino acid residues, with a predicted molecular mass of 51.2 kDa. The deduced protein showed 55-79% identity to other insect -amylases, including Anthonomus grandis, Ips typographus and Sitophilus oryzae -amylases. In depth analysis revealed that the highly conserved three amino acid residues (Asp184, Glu220, and Asp285), which compose the catalytic site are also presented in AmyHha amylase. The AmyHha gene seems to be a single copy in the haploid genome and AmyHha transcription levels were found higher in L2 larvae and adult insects, both corresponding to major feeding phases. Modeling of the AmyHha predicted protein uncovered striking structural similarities to the Tenebrio molitor -amylase also displaying the same amino acid residues involved in enzyme catalysis (Asp184, Glu220 and Asp285). Since AmyHha gene was mostly transcribed in the intestinal tract of H. hampei larvae, the cognate -amylase could be considered a high valuable target to coffee bean insect control by biotechnological strategies.


Santos T.M.,Federal University of Ceará | Souza Filho M.D.S.M.,Embrapa Tropical Agroindustry | Caceres C.A.,University da Integracao Internacional da Lusofonia Afro Brasileira | Rosa M.F.,Embrapa Tropical Agroindustry | And 3 more authors.
Food Hydrocolloids | Year: 2014

This study was conducted to evaluate the influence of cellulose whiskers (CW) from cotton linter and sonication on physical properties of glycerol-plasticized tilapia gelatin films produced by casting technique. The tensile strength and elastic modulus of the films have been improved by the addition of CW, while elongation tended to be impaired by CW loading. The barrier to water vapor has also been improved by the whiskers, and the film transparency has been unaffected. The sonication improved modulus, elongation, and transparency of the films, probably by enhancing CW dispersion on the nanocomposite films, and maybe by inducing some conformational changes on the gelatin matrix. FTIR spectroscopy study on films revealed some gelatin conformational changes induced by cellulose whiskers. © 2014 Elsevier Ltd.


Nascimento D.M.D.,Federal University of Ceará | Almeida J.S.,State University of Ceará | Vale M.D.S.,Embrapa Tropical Agroindustry | Leitao R.C.,Embrapa Tropical Agroindustry | And 4 more authors.
Industrial Crops and Products | Year: 2015

The high lignin content in the unripe coconut fiber limits the use of this biomass as a cellulose nanocrystal source compared to other cellulose-rich materials. The aim of this study was to obtain lignin and biomethane, and evaluate different approaches for extracting cellulose nanocrystal from unripe coconut coir fiber. The environmental evaluation of these approaches is presented in the second part of this paper. Lignin was extracted by acetosolv pulping and cellulose by alkaline hydrogen peroxide bleaching respectively. Were evaluated the biochemical methane potential of the effluents resulting from acetosolv pulping as well as the lignin concentration. Cellulose nanocrystals were prepared from cellulose pulp via four methods: acidic hydrolysis with high acid concentration, acidic hydrolysis with low acid concentration, ammonium persulfate oxidation, and high-power ultrasound. The cellulose nanocrystals were analyzed by FTIR spectroscopy, X-ray diffraction, transmission electron microscopy, and TG analysis. Using these methods, the whole coconut fiber could be used to produce cellulose nanocrystals and lignin. Among the proposed methods, high-power ultrasound showed the highest efficiency in cellulose nanocrystal extraction. © 2016 Elsevier B.V.


Lucena W.A.,Embrapa Cotton | Lucena W.A.,Federal University of Rio Grande do Sul | Pelegrini P.B.,Embrapa Genetic Resources and Biotechnology | Martins-de-Sa D.,Embrapa Genetic Resources and Biotechnology | And 12 more authors.
Toxins | Year: 2014

Bacillus thuringiensis (Bt) is a gram-positive spore-forming soil bacterium that is distributed worldwide. Originally recognized as a pathogen of the silkworm, several strains were found on epizootic events in insect pests. In the 1960s, Bt began to be successfully used to control insect pests in agriculture, particularly because of its specificity, which reflects directly on their lack of cytotoxicity to human health, non-target organisms and the environment. Since the introduction of transgenic plants expressing Bt genes in the mid-1980s, numerous methodologies have been used to search for and improve toxins derived from native Bt strains. These improvements directly influence the increase in productivity and the decreased use of chemical insecticides on Bt-crops. Recently, DNA shuffling and in silico evaluations are emerging as promising tools for the development and exploration of mutant Bt toxins with enhanced activity against target insect pests. In this report, we describe natural and in vitro evolution of Cry toxins, as well as their relevance in the mechanism of action for insect control. Moreover, the use of DNA shuffling to improve two Bt toxins will be discussed together with in silico analyses of the generated mutations to evaluate their potential effect on protein structure and cytotoxicity. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


Nascimento D.M.D.,Federal University of Ceará | Dias A.F.,State University of Ceará | Araujo Junior C.P.D.,Federal University of Ceará | Rosa M.D.F.,Embrapa Tropical Agroindustry | And 2 more authors.
Industrial Crops and Products | Year: 2016

Recently, development of methods for nanomaterial production from natural fibers, especially those from the crop residues in agroindustry, has rapidly increased because of the high availability of residues and the possibility to add value to them. The environmental assessment of such methods is important to continually improve the performance of new nanomaterials throughout the innovation process, especially when it is easier and cheaper to implement modifications in the product design. Unripe coconut fibers are a byproduct of the coconut water industry. These fibers can be extracted from unripe coconut husks, a renewable and abundant source of lignocellulose in the tropical regions. However, recent studies have reported high environmental impacts associated with the method of cellulose nanocrystal extraction from this biomass, mostly related to increased water and energy consumption, use of chlorine-based chemical reagents, and low yield. The aim of the present study was to investigate the environmental impacts of the methods for cellulose nanocrystal extraction from coconut fibers, and to determine the most environmentally sustainable method using Life Cycle Assessment (LCA). Detailed descriptions of these extraction methods have been included in Part I of this study. As cellulose nanocrystal extraction methods allow lignin recovery, this material was analyzed considering two aspects: as a byproduct from the cellulose nanocrystal extraction process, and as a power source for the system. Results indicate that cellulose nanocrystals obtained using the high power ultrasound method cause lower environmental impacts amongst all the assessed categories. The use of lignin as a power source for the biorefinery system does not demonstrate significant differences in relation to its use as a byproduct chemical in other technological applications. The present study reinforced the feasibility of applying LCA to continuously improve the environmental performance of nanomaterials throughout the innovation process, since LCA studies guide the choice of raw materials and technological pathways that result in reduced environmental impacts. © 2016 Elsevier B.V.


Duarte E.B.,Federal University of Ceará | das Chagas B.S.,Federal University of Ceará | Andrade F.K.,Embrapa Tropical Agroindustry | Brigida A.I.S.,Embrapa Food Technology | And 6 more authors.
Cellulose | Year: 2015

In the present work, bionanocomposites based on bacterial cellulose (BC) obtained from alternative sources (cashew juice and sisal liquid waste) and hydroxyapatite (HA) were developed. BC–HA composites were prepared through alternate immersion in CaCl2 and Na2HPO4 solutions. Cellulose was successfully produced from the alternative sources of media without the need for additional supplementation and HA crystals that homogeneously precipitated onto the BC surface. The Ca/P ratio ranged from 1.53 to 1.58, indicating the presence of calcium-deficient HA in the composites; this is a phase similar to biological apatite. After immersion into synthetic body fluid, the HA layer formed on the surface of pure BC and the composites, attesting the material’s bioactivity. Moreover, apatite deposition on the composites was up to three times higher than observed on pure cellulose with no significant desorption of apatite from the composites. These results support that the BC derived from agroindustrial wastes have potential to produce nanocomposites of cellulose/HA for use in bone tissue regeneration. © 2015, Springer Science+Business Media Dordrecht.


Paula G.A.,Federal University of Piauí | Benevides N.M.B.,Federal University of Ceará | Cunha A.P.,Federal University of Ceará | de Oliveira A.V.,Federal University of Ceará | And 3 more authors.
Food Hydrocolloids | Year: 2015

Different proportions of κ-carrageenan, Ι-carrageenan and alginate have been used to prepare glycerol-plasticized edible films, according to a simplex-centroid mixture design. κ-carrageenan was the component which most improved the moisture barrier and overall tensile properties (except elongation), while Ι-carrageenan was the component which most impaired those properties. Alginate was the component which most favored film uniformity (as observed by SEM images) and transparency, while Ι-carrageenan presented a high density of clusters and, accordingly, the highest effect on opacity. Aggregates in Ι-carrageenan probably resulted from an early gelation induced either by the eventual presence of salt contaminants or by cooling the film dispersions to temperatures below 45°C (coil-helix transition temperature of Ι-carrageenan) upon casting. Those aggregates resulted in impaired physical (tensile, barrier, and optical) properties of films containing Ι-carrageenan. © 2015 Elsevier Ltd.


Pereira J.R.,Embrapa Cotton | Duarte A.E.,Regional University of Cariri | Pitombeira J.B.,Federal University of Ceará | da Silva M.A.P.,Regional University of Cariri | And 2 more authors.
Phyton | Year: 2013

An experiment was conducted in dryland conditions of the Brazilian Northeast to determine the number of viable weed seeds (seedbank) in an upland cotton crop, and its distribution in the soil profile, before and after using various herbicide treatments. A randomized block design in a split-plot block scheme with 6 replications was used, where the main plots were constituted by a factorial (13 treatments and 2 sampling soil depths), and the subplots by 2 sampling dates. Te seedbank was determined by germination of the recovered weed seeds obtained from different soil depths. Te highest number of viable weed seeds in the area was found before the application of the herbicide treatments at 0 - 10 cm soil depth. Te treatments metalachlor + diuron; diuron + pendimethalin and the control (no herbicide treatment, weeded weekly during the entire cotton crop cycle) were the most effective in reducing the weed seed-bank in the area.


PubMed | Embrapa Cotton and Embrapa Genetic Resources and Biotechnology
Type: Journal Article | Journal: Toxins | Year: 2014

Bacillus thuringiensis (Bt) is a gram-positive spore-forming soil bacterium that is distributed worldwide. Originally recognized as a pathogen of the silkworm, several strains were found on epizootic events in insect pests. In the 1960s, Bt began to be successfully used to control insect pests in agriculture, particularly because of its specificity, which reflects directly on their lack of cytotoxicity to human health, non-target organisms and the environment. Since the introduction of transgenic plants expressing Bt genes in the mid-1980s, numerous methodologies have been used to search for and improve toxins derived from native Bt strains. These improvements directly influence the increase in productivity and the decreased use of chemical insecticides on Bt-crops. Recently, DNA shuffling and in silico evaluations are emerging as promising tools for the development and exploration of mutant Bt toxins with enhanced activity against target insect pests. In this report, we describe natural and in vitro evolution of Cry toxins, as well as their relevance in the mechanism of action for insect control. Moreover, the use of DNA shuffling to improve two Bt toxins will be discussed together with in silico analyses of the generated mutations to evaluate their potential effect on protein structure and cytotoxicity.

Loading Embrapa Cotton collaborators
Loading Embrapa Cotton collaborators