Papers by Antonio Figueira
Crinipellis perniciosa (Stahel) Singer is the causal agent of witches' broom disease in the Sterc... more Crinipellis perniciosa (Stahel) Singer is the causal agent of witches' broom disease in the Sterculiaceae, Solanaceae, and Bixaceae families. The disease is endemic to the Brazilian Amazon, and was first reported infecting Theobroma cacao (cocoa) in the State of Bahia, Brazil, in 1989. Random amplified polymorphic DNA (RAPD) analyses were performed on 46 isolates of C. perniciosa from cocoa that were collected from 15 counties in Bahia and the Brazilian Amazon. A total of 258 RAPD loci from 20 primers and three mixed primers were analyzed. Of these loci, 108 (42%) were polymorphic, with an average of 4.7 polymorphic loci per primer produced. Genetic similarities were estimated using Nei and Li's index and UPGMA clustering. Bootstrap analysis divided the phenogram into four significantly different clusters: two groups contained isolates from Ariquemes and from Ouro Preto, Rondônia, and the other two separated the isolates from Bahia into two major groups of C. perniciosa, classified as Group 1 (G1) and Group 2 (G2). The two groups of isolates from Bahia differed for their genetic similarity with the isolates from the Brazilian Amazon. The geographic distribution of the groups in Bahia suggests two independent focal points of introduction. Ongoing programs to screen for resistant cocoa genotypes should consider both groups of isolates.
A plant regeneration method with cell suspension cultures of banana, and the effect of biobalisti... more A plant regeneration method with cell suspension cultures of banana, and the effect of biobalistic on regeneration potential are described in this report. Somatic embryos of banana were obtained from indirect embryogenesis of male inflorescence of banana cultivar Maçã (AAB group). Part of the calluses formed (40%) showed embryogenic characteristics (nonfriable, compact and yellow color). The cell suspension, originated from embryogenic calluses, contained clusters of small tightly packed cells with dense cytoplasms, relatively large nuclei and very dense nucleoli. After four months of culture, somatic embryos started to regenerate. The maximum number of regenerated plants was observed between 45 and 60 days after embryo formation. In the first experiment, 401 plants were regenerated from approximately 10 mL of packed cells. In the second experiment, 399 plants were regenerated from a cell suspension six months older than that of the first experiment. Cell transformation using particle bombardment with three different plasmid constructions, containing the uid-A gene, resulted in a strong GUS expression five days after bombardment; however, plant regeneration from bombarded cells was much lower than nonbombarded ones.
Plant nutrient uptake is an active process, requiring energy to accumulate essential elements at ... more Plant nutrient uptake is an active process, requiring energy to accumulate essential elements at higher levels in plant tissues than in the soil solution, while the presence of toxic metals or excess of nutrients requires mechanisms to modulate the accumulation of ions. Genes encoding ion transporters isolated from plants and yeast were used to identify sugarcane putative homologues in the sugarcane expressed sequence tag (SUCEST) database. Five cluster consensi with sequence homology to plant high-affinity phosphate transporter genes were identified. One cluster consensus allowed the prediction of a full-length protein containing 541 amino acids, with 81% amino acid identity to the Nicotiana tabacum NtPT1 gene, consisting of 12 membrane-spanning domains divided by a large hydrophilic charged region. Putative homologues to Arabidopsis thaliana micronutrient transporter genes were also detected in some of the SUCEST libraries. Iron uptake in grasses involves the release of the phytosiderophore mugeneic acid (MA) which chelate Fe 3+ which is then absorbed by a specific transporter. Sugarcane expressed sequence tag (EST) homologous to genes coding for three enzymes of the mugeneic acid biosynthetic pathway [nicotianamine synthase; nicotianamine transferase; and putative mugeneic acid synthetase (ids3)] and a putative Fe 3+ -phytosiderophore transporter were detected. Seven sugarcane sequence clusters were identified with strong homology to members of the ZIP gene family (ZIP1, ZIP3, ZIP4, IRT1 and ZNT1), while four clusters homologous to ZIP2 and three to ZAT were found. Homologues to members of another gene family, Nramp, which code for broad-specificity transition metal transporters were also detected with constitutive expression. Partial transcripts homologous to genes encoding γ-glutamylcysteine synthetase, glutathione synthetase, and phytochelatin synthase (responsible for biosynthesis of the metal chelator phytochelatin) and all four types of the major plant metal-chelator peptide metallothionein (MT) were identified: Type I MT being the most abundant (>1% of seed-library reads), followed by Type II which had a similar pattern of expression as that described for Arabidopsis MT. Identifying and understanding the expression of genes associated with nutrient uptake and metal tolerance could lead to the development of more nutrient-efficient sugarcane cultivars, or might allow the use of sugarcane as a hyper-accumulator plant for the restoration of contaminated areas in phytoremediation programs.
Tree Genetics & Genomes, 2006
Theobroma grandiflorum (cupuassu) is an important fruit tree native to the Brazilian Amazon. Esta... more Theobroma grandiflorum (cupuassu) is an important fruit tree native to the Brazilian Amazon. Establishing the genetic diversity and structure of populations is critical to define long-term strategies for cupuassu conservation presently threatened by rapid deforestation. Three natural populations collected at the putative center of diversity, three groups of accessions established at a germplasm collection, and one derived from commercial plantings were analyzed. The genetic diversity was assessed using 21 polymorphic microsatellite loci originally developed for Theobroma cacao, disclosing a total of 113 alleles. The estimated genetic diversity parameters averaged over cupuassu populations (A=3.53 alleles per locus; H e =0.426; H o =0.346) were lower than the values reported for other Neotropical tree species. The three natural populations presented a positive and significant fixation index (f), ranging from 0.133 to 0.234. Cupuassu apparently adhered to a general pattern of genetic diversity structure of some Neotropical tree species occurring at low densities, with a low intrapopulation genetic diversity and important levels of endogamy, possibly due to biparental inbreeding derived from the presence of spatial genetic structure in the populations. A high level of genetic divergence was detected among the natural populations (θ p =0.301), a strong differentiation caused by limited gene flow, and suggesting that human interference in spreading and/or stimulating plantings might have had a smaller effect than expected. The approximate location of the T. grandiflorum center of diversity could not be confirmed by analyzing natural populations from the putative region.
Genetics and Molecular Biology, 2003
The aim of this research was to study the mating system of a natural population of Theobroma gran... more The aim of this research was to study the mating system of a natural population of Theobroma grandiflorum (cupuassu) from Nova Ipixuna, Pará state, using microsatellite markers. Eight polymorphic microsatellite loci were analyzed in eight families, each represented by 10 six-month old seedlings derived from open-pollinated pods. The estimation for the multilocus outcrossing rate ( $ tm = 1.0) and
Molecular Ecology Notes, 2006
Theobroma grandiflorum (cupuassu) is an important fruit tree native to the Brazilian Amazon. Fort... more Theobroma grandiflorum (cupuassu) is an important fruit tree native to the Brazilian Amazon. Forty-eight microsatellite loci developed for the congener Theobroma cacao were tested in cupuassu , and 29 (60.4%) produced robust alleles. The analyses of 216 cupuassu accessions using the 21 polymorphic microsatellite loci revealed a total of 113 alleles. The number of alleles per polymorphic locus ranged from two to 11, with an average of 5.38 alleles per locus. The average observed heterozygosity was 0.343, while the mean expected heterozygosity was 0.614. The successful transferability of T. cacao microsatellite primers to cupuassu was consistent with currently accepted phylogeny.
Bmc Plant Biology, Mar 12, 2013
Background: Banana cultivars are mostly derived from hybridization between wild diploid subspecie... more Background: Banana cultivars are mostly derived from hybridization between wild diploid subspecies of Musa acuminata (A genome) and M. balbisiana (B genome), and they exhibit various levels of ploidy and genomic constitution. The Embrapa ex situ Musa collection contains over 220 accessions, of which only a few have been genetically characterized. Knowledge regarding the genetic relationships and diversity between modern cultivars and wild relatives would assist in conservation and breeding strategies. Our objectives were to determine the genomic constitution based on Internal Transcribed Spacer (ITS) regions polymorphism and the ploidy of all accessions by flow cytometry and to investigate the population structure of the collection using Simple Sequence Repeat (SSR) loci as co-dominant markers based on Structure software, not previously performed in Musa.
Euphytica, 2003
Microsatellite markers were used to characterize 35 banana (Musa spp.) genotypes cultivated in Br... more Microsatellite markers were used to characterize 35 banana (Musa spp.) genotypes cultivated in Brazil, including triploid cultivars and tetraploid hybrids. A total of 33 Musa-specific primers were tested, and 11 produced clear, reproducible and discrete bands. The average number of alleles amplified per primer was 6.1, ranging from 4 to 8, with a total of 67 alleles identified. Phenetic analysis based on Jaccard similarity index derived from presence or absence of the alleles agreed with the morphological classification. Bootstrap analysis divided the genotypes into four clusters, according to genomic group and subgroup classification. The first cluster contained the majority of cultivars which have 'A' genome alone; while the second contained all triploid cultivars of the subgroup Prata (Pome) and their tetraploid hybrids. The third cluster contained cultivar 'Maçã' together with other genotypes considered for breeding purposes as similar to the Silk subgroup. These last two clusters formed a larger group including the majority of genotypes that resulted from hybridization between M. acuminata and M. balbisiana. The microsatellite loci were highly informative, with some pair of primers generating an unique fingerprinting for each genomic group and discriminating a genotype of doubtful classification, although somatic mutants from a subgroup were seldom distinguished from their original clone. Tetraploid hybrids exhibited distortion in the proportion of alleles donated by their triploid female parent. For a few primers, some genotypes exhibited a higher number of alleles than expected from their ploidy level, suggesting the occurrence of duplicated alleles or duplicated chromosomal regions.
Folha Med, Dec 1, 1999
Resumo: Com o objetivo de estudar as complicações da esfincterotomia endoscópica, da papilotomia ... more Resumo: Com o objetivo de estudar as complicações da esfincterotomia endoscópica, da papilotomia transduodenal, da colecistectomia e da extração de cálculos de colédoco por via convencional foram estudados 101 doentes com colecistite crônica calculosa e ...
Folha Med, Aug 1, 1998
Base de dados : LILACS. Pesquisa : 233525 [Identificador único]. Referências encontradas : 1 [ref... more Base de dados : LILACS. Pesquisa : 233525 [Identificador único]. Referências encontradas : 1 [refinar]. Mostrando: 1 .. 1 no formato [Detalhado]. página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. experimental, Documentos relacionados. Id: 233525. ...
Folha Med, Oct 1, 1998
Resumo: A exploração cirúrgica convencional do colédoco para remoção de cálculos é referencial pa... more Resumo: A exploração cirúrgica convencional do colédoco para remoção de cálculos é referencial para comparação de resultados de outras técnicas. A colangioscopia flexível constitui um método complementar da coledocolitotomia na cirurgia convencional, na ...
Pl Mol Biol Rep, 2001
Large-scale use of molecular markers in plant breeding is limited by the throughput capacity for ... more Large-scale use of molecular markers in plant breeding is limited by the throughput capacity for genotyping. DNA polymorphisms can be detected in denaturing polyacrylamide gels indirectly by nucleotide labeling or directly by staining. Fluorescentlabeling or radiolabeling requires sophisticated infrastructure not always available in developing countries. We present an improved low-cost method for silver staining and compare it to 2 other methods for their ability to detect simple sequence repeat polymorphisms in denaturing polyacrylamide gels bound to glass plates. The 3 procedures differed in their requirement for an oxidation pretreatment, preexposure with formaldehyde during silver nitrate impregnation, inclusion of silver thiosulfate, and by their replacement of sodium carbonate for sodium hydroxide to establish alkaline conditions for silver ion reduction. All methods detected the same banding pattern and alleles. However, important differences in sensitivity, contrast, and background were observed. Two methods gave superior sensitivity, detecting down to 1 ~L of loaded amplification products. Our improved method gave lower backgrounds and allowed reutilization of staining solutions. The use of thin (<1 mm) denaturing sequencing gels allows genotyping of 60-96 samples within 4 h. Use of smaller loading sample volumes and reutilization of staining solutions further reduced costs.
Journal of Microbiological Methods, Sep 1, 2010
Various molecular systems are available for epidemiological, genetic, evolutionary, taxonomic and... more Various molecular systems are available for epidemiological, genetic, evolutionary, taxonomic and systematic studies of innumerable fungal infections, especially those caused by the opportunistic pathogen C. albicans. A total of 75 independent oral isolates were selected in order to compare Multilocus Enzyme Electrophoresis (MLEE), Electrophoretic Karyotyping (EK) and Microsatellite Markers (Simple Sequence Repeats - SSRs), in their abilities to differentiate and group C. albicans isolates (discriminatory power), and also, to evaluate the concordance and similarity of the groups of strains determined by cluster analysis for each fingerprinting method. Isoenzyme typing was performed using eleven enzyme systems: Adh, Sdh, M1p, Mdh, Idh, Gdh, G6pdh, Asd, Cat, Po, and Lap (data previously published). The EK method consisted of chromosomal DNA separation by pulsed-field gel electrophoresis using a CHEF system. The microsatellite markers were investigated by PCR using three polymorphic loci: EF3, CDC3, and HIS3. Dendrograms were generated by the SAHN method and UPGMA algorithm based on similarity matrices (S(SM)). The discriminatory power of the three methods was over 95%, however a paired analysis among them showed a parity of 19.7-22.4% in the identification of strains. Weak correlation was also observed among the genetic similarity matrices (S(SM)(MLEE)xS(SM)(EK)xS(SM)(SSRs)). Clustering analyses showed a mean of 9+/-12.4 isolates per cluster (3.8+/-8 isolates/taxon) for MLEE, 6.2+/-4.9 isolates per cluster (4+/-4.5 isolates/taxon) for SSRs, and 4.1+/-2.3 isolates per cluster (2.6+/-2.3 isolates/taxon) for EK. A total of 45 (13%), 39 (11.2%), 5 (1.4%) and 3 (0.9%) clusters pairs from 347 showed similarity (S(J)) of 0.1-10%, 10.1-20%, 20.1-30% and 30.1-40%, respectively. Clinical and molecular epidemiological correlation involving the opportunistic pathogen C. albicans may be attributed dependently of each method of genotyping (i.e., MLEE, EK, and SSRs) supplemented with similarity and grouping analysis. Therefore, the use of genotyping systems that give results which offer minimum disparity, or the combination of the results of these systems, can provide greater security and consistency in the determination of strains and their genetic relationships.
HortScience: a publication of the American Society for Horticultural Science
The Abstracts that follow are arranged by type of session (Posters first, then Orals, Colloquia, ... more The Abstracts that follow are arranged by type of session (Posters first, then Orals, Colloquia, and Workshops). The Poster abstract numbers correspond to the Poster Board number at which the Poster will be presented. Three inoculation methods, including cutting of a leaf, drenching, and point inoculation, were compared in an effort to screen the susceptibility of Chinese cabbage to soft rot disease caused by Erwinia carotovora subsp. carotovora. Threeto 4-week-old seedlings from 10 lines of cabbage with 16-h-old bacterial culture were routinely used. Inoculated seedlings were kept at 25.0 ± 10.0 °C for 48 h with saturated water vapor using a plastic tunnel in a greenhouse. Sixty-day-old mature plants were produced and inoculated in a greenhouse. Severity of symptoms, which were observed from percentage of plant infected was scored as from
Ao CNPq, pelo apoio financeiro na concessão da bolsa de doutorado; À FAPESP, pelo financiamento d... more Ao CNPq, pelo apoio financeiro na concessão da bolsa de doutorado; À FAPESP, pelo financiamento do projeto; Ao prof. Dr. Augusto Tulmann Neto, que por acreditar na minha capacidade, me ofereceu a oportunidade e as condições para desenvolver este trabalho; Ao prof. Dr. Antonio Figueira, que me ungiu com todo conhecimento, profissionalismo e competência, dando-me exemplos de garra e força de vontade; Ao Sebastião de Oliveira e Silva, da Embrapa Mandioca e Fruticultura, pela doação do material vegetal, Ao amigo Alexandre Coelho, pelo auxílio na análise dos dados; Ao prof. Dr. Roland Vencovsky, por ter me honrado com suas valiosas sugestões na análise e interpretação dos dados; Aos professores do Departamento de Genética, pela minha formação acadêmica, Aos funcionários do departamento de Genética da ESALQ/USP, pelo carinho e amizade, Aos funcionários do laboratório de Melhoramento de Plantas, do CENA/USP, pela ajuda e amizade, À prof. Dra. Maria Tereza Vitral de Carvalho Derbyshire, por todos os favores concedidos, Aos amigos Rodrigo Rocha Latado e Rafael Moyses Alves, pelas trocas de experiências durante a condução dos experimentos; Aos amigos Carlos Rogério de Souza Silva e Cristiane Cristina Borges, pela colaboração, convivência e amizade; v Ao João Geraldo Brancalion, do laboratório de informática do CENA, por toda a ajuda prestada, Aos meus pais, por todas as vezes que renunciaram a si mesmos em prol de minha formação, Aos meus irmãos, pelo privilégio de tê-los como irmãos, Ao meu marido, Paulo, por ter me ensinado que os caminhos da vitória são percorridos com amor, determinação, coragem e humildade, Ao meu filho, João Victor, por ter me amado de forma incondicional, mesmo quando não fui o melhor exemplo de mãe, À minha sogra, Elsa, que sempre me socorreu nos momentos de grandes apertos;
Cells, tissues, organs, Jan 24, 2015
Repulsive guidance molecules (RGMs) compose a family of glycosylphosphatidylinositol (GPI)-anchor... more Repulsive guidance molecules (RGMs) compose a family of glycosylphosphatidylinositol (GPI)-anchored axon guidance molecules and perform several functions during neural development. New evidence has suggested possible new roles for these axon guidance molecules during skeletal muscle development, which has not been investigated thus far. In the present study, we show that RGMa, RGMb and RGMc are all induced during skeletal muscle differentiation in vitro. Immunolocalization performed on adult skeletal muscle cells revealed that RGMa, RGMb and RGMc are sarcolemmal proteins. Additionally, RGMa was found to be a sarcoplasmic protein with a surprisingly striated pattern. RGMa colocalization with known sarcoplasmic proteins suggested that this axon guidance molecule is a skeletal muscle sarcoplasmic protein. Western blot analysis revealed two RGMa fragments of 60 and 33 kDa, respectively, in adult skeletal muscle samples. RGMa phenotypes in skeletal muscle cells (C2C12 and primary myoblas...
Sugarcane is a major crop worldwide, raw material for sugar and ethanol production. Drought is on... more Sugarcane is a major crop worldwide, raw material for sugar and ethanol production. Drought is on of the most limiting factor that affects sugarcane productivity. In order to understand the mechanisms of drought response, field and greenhouse essays were conducted with two drought-contrasting sugarcane genotypes (IACSP94-2094/tolerant and IACSP97-7065/sensitive). A microarray analysis, conducted with 14,522 genes using material grown on field, and a global gene expression analysis performed by RNAseq with plants grown in greenhouse have both identified several genes that are up/down-regulated under drought stress. Among these, nine genes (presented in both assays) were selected to be validated by qPCR using leaves. Four genes (Water Stress, Hormone Biosynthesis, Unknown1 and Unknown2) showed higher levels of transcripts in IACSP97-7065 in greenhouse, while levels in IACSP94-2094 were higher on field. Dehydrin and Cell Cycle genes showed the highest expression levels in sensitive gen...
Drought is the most important abiotic stress that affects sugarcane productivity. Analyses of mic... more Drought is the most important abiotic stress that affects sugarcane productivity. Analyses of microarray and RNAseq conduced with two drought contrasting genotypes (IACSP94-2094/tolerant and IACSP97-7065/sensitive) on field and at greenhouse have identified several genes that are up/down-regulated on drought condition. From the set of genes validated by quantitative PCR, Dehydrin, Dirigent-jacalin and Lipoxygenase (ScLOX) were chosen as target for functional analyses using rice and sugarcane transgenic plants. The full-length coding sequences of these genes were accessed by SMARTer RACE cDNA Amplification Kit (Clontech) using the tolerant genotype IACSP94-2094 mRNA. The cloning was performed using the vector pGEM-T Easy (Promega) and E. coli DH10B lineage, and sequences subcloned into pDONR 211 gateway vector. The full length coding sequence of Dehydrin and Dirigent-jacalin genes were successful isolated and cloned. From the 10 Dehydrin clones sequenced, two allelic variant were ide...
BMC Genomics, 2015
Background: Providing double-stranded RNA (dsRNA) to insects has been proven to silence target ge... more Background: Providing double-stranded RNA (dsRNA) to insects has been proven to silence target genes, and this approach has emerged as a potential method to control agricultural pests by engineering plants to express insect dsRNAs. A critical step of this technology is the screening of effective target genes essential for insect development and/or survival. The tomato leafminer (Tuta absoluta Meyrick) is a major Solanum lycopersicum (tomato) pest that causes significant yield losses and has recently invaded Europe, from where it is spreading at an alarming rate. To explore RNA interference (RNAi) against T. absoluta, sequence information on potential target genes is necessary, but only a few sequences are available in public databases. Results: We sequenced six libraries from RNA samples from eggs, adults, and larvae at four stages, obtaining an overall total of around 245 million reads. The assembled T. absoluta transcriptome contained 93,477 contigs with an average size of 1,574 bp, 59.8 % of which presented positive Blast hits, with 19,995 (21.4 %) annotated by gene ontology. From the transcriptome, most of the core genes of the RNAi mechanism of Lepidoptera were identified indicating the potential suitability of T. absoluta for gene silencing. No contigs displayed significant similarity with a RNA-dependent RNA Polymerase. Genes from the juvenile hormone and ecdysteroid biosynthetic pathways were identified, representing potential target genes for systemic silencing. Comparisons of transcript profiles among stages revealed 1,577 genes differentially expressed at earlier larval stages, from which potential gene targets were identified. Five of these genes were evaluated using in vitro transcribed dsRNA absorbed by tomato leaflets, which were fed to 1 st instar T. absoluta larvae, resulting in significant reduction of larval body weight while exhibiting significant knockdown for three of the genes. Conclusions: The transcriptome we generated represents a valuable genomic resource for screening potential gene targets that affect the development or survival of T. absoluta larvae. Five novel genes that showed greater expression at the 1 st larval stage were demonstrated to be effective potential RNAi targets by reducing larval weight and can be considered good candidates for use in RNAi-mediated crop protection.
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Papers by Antonio Figueira