Navegando por Autor "Barros, Everaldo G. de"

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Fermentation of maltose and starch by Klebsiella oxytoca P2
(Biotechnology Letters, 1998-12) Santos, Vera L. dos; Guimarães, Walter V.; Barros, Everaldo G. de; Araújo, Elza F.
Klebsiella oxytoca P2, which has genes from Zymomonas mobilis encoding the alcohol dehydrogenase and pyruvate decarboxylase integrated in its chromosome, fermented 50 g maltose/l to 25.4 g of ethanol/l. It also fermented 10, 20 and 40 g starch/l yielding 4, 8.4, and 17.7 g ethanol/l, respectively, representing 72, 75 and 78% of the theoretical yield.
Mapping of quantitative trait loci for butter content and hardness in cocoa beans (Theobroma Cacao L.)
(Plant Molecular Biology Reporter, 2009-06) Queiroz, Vagner T. de; Araújo, Ioná S.; Souza Filho, Gonçalo A. de; Pereira, Messias G.; Faleiro, Fábio G.; Guimarães, Cláudia T.; Moreira, Maurílio A.; Barros, Everaldo G. de; Machado, Regina C. R.; Pires, José L.; Schenell, Raymond; Lopes, Uilson V.
Cocoa butter is an important raw material for the chocolate, pharmaceutical, and cosmetic industries. The butter content and quality in cocoa beans are genetically controlled characteristics, and affect its commercial value and industrial applicability. In the present work, an F2 population derived from the cross between the ICS-1 and Scavina-6 cocoa clones was used for molecular mapping. A linkage map was constructed based on amplified fragment length polymorphism, random amplified polymorphic DNA, and simple sequence repeat markers, resulting in a total of 273 markers, distributed in 14 linkage groups (LGs). Phenotyping of butter content was performed after ether extraction and butter hardness was determined by sweeping differential calorimetry. One quantitative trait locus (QTL) associated to butter content was mapped at linkage group 9 (LG9) and two QTLs for butter hardness were identified at linkage groups 9 and 7 (LG9 and LG7). The two QTLs mapped at the LG9 explained 51.0% and 28.8% of the phenotypic variation for butter content and hardness, respectively. These QTLs were concentrated in the same map region, suggesting a close genetic linkage or pleiotropic effect. The QTLs identified may be useful in further marker-assisted selection breeding programs aimed at cocoa butter quality improvement.
Polymorphism in the internal transcribed spacer (ITS) of the ribosomal DNA of 26 isolates of ectomycorrhizal fungi
(Genetics and Molecular Biology, 2002) Gomes, Eliane A.; Kasuya, Maria Catarina M.; Barros, Everaldo G. de; Borges, Arnaldo C.; Araújo, Elza F.
Inter- and intraspecific variation among 26 isolates of ectomycorrhizal fungi belonging to 8 genera and 19 species were evaluated by analysis of the internal transcribed sequence (ITS) of the rDNA region using restriction fragment length polymorphism (RFLP). The ITS region was first amplified by polymerase chain reaction (PCR) with specific primers and then cleaved with different restriction enzymes. Amplification products, which ranged between 560 and 750 base pairs (bp), were obtained for all the isolates analyzed. The degree of polymorphism observed did not allow proper identification of most of the isolates. Cleavage of amplified fragments with the restriction enzymes Alu I, Hae III, Hinf I, and Hpa II revealed extensive polymorphism. All eight genera and most species presented specific restriction patterns. Species not identifiable by a specific pattern belonged to two genera: Rhizopogon (R. nigrescens, R. reaii, R. roseolus, R. rubescens and Rhizopogon sp.), and Laccaria (L. bicolor and L. amethystea). Our data confirm the potential of ITS region PCR-RFLP for the molecular characterization of ectomycorrhizal fungi and their identification and monitoring in artificial inoculation programs.
Processing of soybean products by semipurified plant and microbial α-Galactosidases
(Journal of Agricultural and Food Chemistry, 2006-05-12) Falkoski, Daniel L.; Guimarães, Valéria M.; Callegari, Carina M.; Reis, Angélica P.; Barros, Everaldo G. de; Rezende, Sebastião T. de
Galactooligosaccharides (GO) are responsible for intestinal disturbances following ingestion of legume-derived products. Enzymatic reduction of GO level in these products is highly desirable to improve their acceptance. For this purpose, plant and microbial semipurified α-galactosidases were used for GO hydrolysis in soybean flour and soy molasses. α-Galactosidases from soybean germinating seeds, Aspergillus terreus, and Penicillium griseoroseum presented maximal activities at pH 4.0−5.0 and 45−65 °C. The KM,app values determined for raffinose by the soybean, A. terreus, and P. griseoroseum α-galactosidases were 3.44, 19.39, and 20.67 mM, respectively. The enzymes were completely inhibited by Ag+ and Hg2+, whereas only soybean enzyme was inhibited by galactose. A. terreus α-galactosidase was more thermostable than the enzymes from the other two sources. This enzyme maintained about 100% of its original activity after 3 h at 60 °C. The microbial α-galactosidases were more efficient for reducing GO in soybean flour and soy molasses than soybean enzyme.
Quantification of anti-nutritional factors and their correlations with protein and oil in soybeans
(Anais da Academia Brasileira de Ciências, 2015-08-31) Bueno, Rafael D.; Borges, Leandro L.; God, Pedro I.V. Good; Piovesan, Newton D.; Teixeira, Arlindo I.; Cruz, Cosme Damião; Barros, Everaldo G. de
Soybeans contain about 30% carbohydrate, mainly consisting of non-starch polysaccharides (NSP) and oligosaccharides. NSP are not hydrolyzed in the gastrointestinal tract of monogastric animals. These NSP negatively affect the development of these animals, especially the soluble fraction. This work aimed to establish a method to quantify NSP in soybeans, using high performance liquid chromatography (HPLC), and to estimate correlations between NSP, oligosaccharides, protein and oil. Sucrose, raffinose + stachyose, soluble and insoluble NSP contents were determined by HPLC. Oil and protein contents were determined by near-infrared spectroscopy (NIRS). The soluble PNAs content showed no significant correlation with protein, oil, sucrose and raffinose + stachyose contents, but oligosaccharides showed a negative correlation with protein content. These findings open up the possibility of developing cultivars with low soluble NSP content, aiming to develop feed for monogastric animals.
Single nucleotide polymorphism discovery in common bean
(Molecular Breeding, 2011-09-13) Souza, Thiago Lı́vio P. O.; Barros, Everaldo G. de; Bellato, Claudia M.; Hwang, Eun-Young; Cregan, Perry B.; Pastor-Corrales, Marcial A.
Single nucleotide polymorphisms (SNPs) were discovered in common bean (Phaseolus vulgaris L.) via resequencing of sequence-tagged sites (STSs) developed by PCR primers previously designed to soybean shotgun and bacterial artificial chromosome (BAC) end sequences, and by primers designed to common bean genes and microsatellite flanking regions. DNA fragments harboring SNPs were identified in single amplicons from six contrasting P. vulgaris genotypes of the Andean (Jalo EEP 558, G 19833, and AND 277) and Mesoamerican (BAT 93, DOR 364, and Rudá) gene pools. These genotypes are the parents of three common bean recombinant inbred line mapping populations. From an initial set of 1,880 PCR primer pairs tested, 265 robust STSs were obtained, which could be sequenced in each one of the six common bean genotypes. In the resulting 131,120 bp of aligned sequence, a total of 677 SNPs were identified, including 555 single-base changes (295 transitions and 260 transversions) and 122 small nucleotide insertions/deletions (indels). The frequency of SNPs was 5.16 SNPs/kb and the mean nucleotide diversity, expressed as Halushka’s theta, was 0.00226. This work represents one of the first efforts aimed at detecting SNPs in P. vulgaris. The SNPs identified should be an important resource for common bean geneticists and breeders for quantitative trait locus discovery, marker-assisted selection, and map-based cloning. These SNPS will be also useful for diversity analysis and microsynteny studies among legume species.