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Search Results: 1 - 10 of 12795 matches for " Marcelo;Targon "
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Citrus exocortis viroid and Hop Stunt viroid Doubly infecting grapevines in Brazil
Eiras, Marcelo;Targon, Maria Luisa P.N.;Fajardo, Thor V.M.;Flores, Ricardo;Kitajima, Elliot W.;
Fitopatologia Brasileira , 2006, DOI: 10.1590/S0100-41582006000500002
Abstract: viroids, non-protein-coding small (246-401 nt) circular single-stranded rnas with autonomous replication, are currently classified into two families. within the family pospiviroidae, citrus exocortis viroid (cevd) belongs to the genus pospiviroid while hop stunt viroid (hsvd) is the single member of the genus hostuviroid. these pathogens are distributed worldwide and infect a large number of hosts. in brazil, isolates of cevd and hsvd have been detected in both citrus and grapevine. to characterize and study the genetic variability of these viroids, total rna from leaves of grapevine vitis vinifera 'cabernet sauvignon' and v. labrusca 'niagara rosada' from bento gon?alves, rs, was used as a template for rt-pcr amplification with specific primers for the five viroids described infecting grapevines [hsvd, cevd, grapevine yellow speckle viroid 1 (gysvd-1), grapevine yellow speckle viroid 2 (gysvd-2) and australian grapevine viroid (agvd)]. leaf samples of citrus medica infected with cevd from s?o paulo were also analyzed. the resulting products were separated by agarose gel electrophoresis and dna fragments of the expected size were eluted, cloned and sequenced. the grapevine samples analyzed were doubly infected by cevd and hsvd. a phylogenetic analysis showed that the brazilian grapevine hsvd variants clustered with other grapevine hsvd variants, forming a specific group separated from citrus variants, whereas the brazilian cevd variants clustered with other citrus and grapevine variants.
Viroides em citros
Eiras, Marcelo;Silva, Simone Rodrigues;Stuchi, Eduardo Sanches;Targon, Maria Luisa Penteado Natividade;Carvalho, Sérgio Alves;
Tropical Plant Pathology , 2009, DOI: 10.1590/S1982-56762009000500001
Abstract: viroids are the smallest known plant pathogens consisting of a non-encapsidated, circular, single-stranded rna that replicate autonomously in their host plants. viroids are classified into two families (pospiviroidae and avsunviroidae). all citrus viroids belong to the pospiviroidae family (species that present a central conserved region, replicate in the nucleus of infected cells and lack of ribozyme activity) with five citrus viroid species: citrus exocortis viroid, cevd (pospiviroid), hop stunt viroid, hsvd (hostuviroid), citrus bark cracking viroid, cbcvd (cocadviroid) and citrus bent leaf viroid, cblvd and citrus dwarfing viroid, cdvd (apscaviroid). in addition, citrus viroid original source (cvd-os) and, more recently, citrus viroid v (cvd-v) have been proposed as tentative species of the genus apscaviroid. citrus viroids are graft-transmitted and their dissemination occurs mainly by propagation of contaminated material. it is known that they have a broad host range, infecting species of citrus and plants of citrus-related genera. two important diseases in citrus are viroid-induced: (i) exocortis; (ii) and cachexia. symptoms vary from severe to asymptomatic, and their control is based on preventive measures as availability of viroid-free budwood as a source of propagation material follow by adequate indexing procedures. the purpose of this review is to present the reader the recent advances on citrus viroid research, mainly on taxonomy, geographical distribution, methods of detection, indexing and cleaning, epidemiology and control.
In silico prediction of gene expression patterns in Citrus flavedo
Berger, Irving J.;Freitas-Astúa, Juliana;Reis, Marcelo S.;Targon, Maria Luísa P.N.;Machado, Marcos A.;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500004
Abstract: out of the 18,942 flavedo expressed sequences (clusters plus singletons) in citrus sinensis from the citrus est project (citest), 25 were statistically supported to be differentially expressed in this tissue after a double in silico hybridization strategy against leaf-, flower-, and bark-derived ests. five of them, two terpene synthases and three o-methyltransferases, are absent in the other citrus tissues with concomitant 2x2 statistics, supporting the hypothesis that they are putative flavedo-specific expressed sequences. the pattern of these differentially expressed sequences during fruit development suggests that most of them are developmentally regulated. some expressed gene products, including a putative germin-like protein highly expressed in flavedo, are shown to be promising candidates for further characterization. in addition to promoter seeking, this kind of analysis can lead to gene discovery, tissue-specific and tissue-enriched expression pattern predictions (as shown herein) and can also be adopted as an in silico first, and probably reliable approach, for detecting expression profiles from est sequencing efforts before experimental validation is available or for heuristically guiding that validation.
Differential expression of genes identified from Poncirus trifoliata tissue inoculated with CTV through EST analysis and in silico hybridization
Cristofani-Yaly, Mariangela;Berger, Irving J.;Targon, Maria Luisa P.N.;Takita, Marco A.;Dorta, Sílvia de O.;Freitas-Astúa, Juliana;Souza, Alessandra A. de;Boscariol-Camargo, Raquel L.;Reis, Marcelo S.;Machado, Marcos A.;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500025
Abstract: citrus is the most important fruit crop in brazil and citrus tristeza virus (ctv) is considered one of the most important pathogens of citrus. most citrus species and varieties are susceptible to ctv infection. however, poncirus trifoliata, a close relative of citrus, is resistant to the virus. in order to better understand the responses of citrus plants to the infection of ctv, we constructed expressed sequence tag (est) libraries with tissues collected from poncirus trifoliata plants, inoculated or not with citrus tristeza virus at 90 days after inoculation, grafted on rangpur lime rootstocks. we generated 17,867 sequence tags from poncirus trifoliata inoculated (8,926 reads) and not (8,941 reads) with a severe ctv isolate. a total of 2,782 tcs (tentative consensi sequences) were obtained using both cdna libraries in a single clusterization procedure. by the in silico hybridization approach, 289 tcs were identified as differentially expressed in the two libraries. a total of 121 tcs were found to be overexpressed in plants infected with ctv and were grouped in 12 primary functional categories. the majority of them were associated with metabolism and defense response. some others were related to lignin, ethylene biosynthesis and pr proteins. in general, the differentially expressed transcripts seem to be somehow involved in secondary plant response to ctv infection.
Analysis of expressed sequence tags from Citrus sinensis L. Osbeck infected with Xylella fastidiosa
Souza, Alessandra A. de;Takita, Marco A.;Coletta-Filho, Helvécio D.;Targon, Maria Luisa P.N.;Carlos, Eduardo F.;Locali-Fabris, Eliane C.;Amaral, Alexandre M.;Freitas-Astúa, Juliana;Silva-Pinhati, Ana Carla O.;Boscariol-Camargo, Raquel L.;Berger, Irving J.;Rodrigues, Carolina M.;Reis, Marcelo S.;Machado, Marcos A.;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500023
Abstract: in order to understand the genetic responses resulting from physiological changes that occur in plants displaying citrus variegated chlorosis (cvc) symptoms, we adopted a strategy of comparing two est libraries from sweet orange [citrus sinensis (l.) osbeck]. one of them was prepared with plants showing typical cvc symptoms caused by xylella fastidiosa and the other with non-inoculated plants. we obtained 15,944 ests by sequencing the two cdna libraries. using an in silico hybridization strategy, 37 genes were found to have significant variation at the transcriptional level. within this subset, 21 were up-regulated and 16 were down-regulated in plants with cvc. the main functional categories of the down-regulated transcripts in plants with cvc were associated with metabolism, protein modification, energy and transport facilitation. the majority of the up-regulated transcripts were associated with metabolism and defense response. some transcripts associated with adaptation to stress conditions were up-regulated in plants with cvc and could explain why plants remain alive even under severe water and nutritional stress. others of the up-regulated transcripts are related to defense response suggesting that sweet orange plants activate their defense machinery. the genes associated with stress response might be expressed as part of a secondary response related to physiological alterations caused by the infection.
In silico analysis of ESTs from roots of Rangpur lime (Citrus limonia Osbeck) under water stress
Boscariol-Camargo, Raquel L.;Berger, Irving J.;Souza, Alessandra A.;Amaral, Alexandre M. do;Carlos, Eduardo F.;Freitas-Astúa, Juliana;Takita, Marco A.;Targon, Maria Luisa P.N.;Medina, Camilo L.;Reis, Marcelo S.;Machado, Marcos A.;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500019
Abstract: citest project resulted in the construction of cdna libraries from different citrus sp. tissues under various physiological conditions. among them, plantlets of rangpur lime were exposed to hydroponic conditions with and without water stress using peg6000. rna from roots was obtained and generated a total of 4,130 valid cdna reads, with 2,020 from the non-stressed condition and 2,110 from the stressed set. bioinformatic analyses measured the frequency of each read in the libraries and yielded an in silico transcriptional profile for each condition. a total of 40 contigs were differentially expressed and allowed to detect up-regulated homologue sequences to well known genes involved in stress response, such as aquaporins, dehydrin, sucrose synthase, and proline-related synthase. some sequences could not be classified by using funcat and remained with an unknown function. a large number of sequences presented high similarities to annotated genes involved with cell energy, protein synthesis and cellular transport, suggesting that rangpur lime may sustain active cell growth under stressed condition. the presence of membrane transporters and cell signaling components could be an indication of a coordinated morphological adaptation and biochemical response during drought, helping to explain the higher tolerance of this rootstock to water stress.
Diversidade de Phytophthora parasitica isolados de Citrus usando seqüências de nucleotídeos da regi?o ITS-5.8S rDNA
Rosa, Daniel Dias;Machado, Marcos Antonio;Targon, Maria Luisa Penteado Natividade;Furtado, Edson Luiz;
Summa Phytopathologica , 2006, DOI: 10.1590/S0100-54052006000200017
Abstract: phytophthoraparasitica is been considered one of the most prevalent citrus soilborn pathogens in brazil. fourteen isolates were collected in different region of s?o paulo state. amplification of the its region using primers its1 and its2 produced dna fragments of 812 to 860 bp, that were compared with other sequences obtained to gene bank (ncbi). neighbor-joining analysis, with 1000 bootstrap revealed an average similarity of 99,3 to 100% between the isolates, and 98,1 to 99,9% between s. paulo state isolates and p. nicotianae (= phytophthoraparasitica)obtained from the gene bank (gi|8927482). the its1 was more conserved than to the its2. this is a good tool for quick diagnosis of phytophthora citrus diseases.
Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis
Rosa, Daniel D.;Campos, Magnólia A.;Targon, Maria Luisa P.N.;Souza, Alessandra A.;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500028
Abstract: due to the economic importance of gummosis disease for the citriculture, studies on p. parasitica-citrus interaction comprise a significant part in the brazilian citrus genome data bank (citest). among them, two cdna libraries constructed from two different growth conditions of the p. parasitica pathogen are included which has generated the pp/citest database (citest - center apta citros sylvio moreira/iac- millennium institute). through this genomic approach and clustering analyses the following has been observed: out of a total of 13,285 available in the phytophthora parasitica database, a group of 4,567 clusters was formed, comprising 2,649 singlets and 1,918 contigs. out of a total of 4,567 possible genes, only 2,651 clusters were categorized; among them, only 4.3% shared sequence similarities with pathogenicity factors and defense. some of these possible genes (103) corresponding to 421 ests, were characterized by phylogenetic analysis and discussed. a comparison made with the cogeme database has shown homology which may be part of an evolutionary pathogenicity pathway present in phytophthora and also in other fungi. many of the genes which were identified here, which may encode proteins associated to mechanisms of citrus gummosis pathogenicity, represent only one facet of the pathogen-host phytophthora - citrus interaction.
Tn/T Specific Agglutinin from Estuarine Crab Scylla Serrata with Potent Mitogenic Activity on Mouse Splenocytes and Antiproliferative Effect on Hepatocellular Carcinoma (HepG2) Cell
Jhuma Pramanik, Urmimala Chatterjee, Gautam Mondal, Patricia Targon Campana and Bishnu Pada Chatterjee
Glycobiology Insights , 2012, DOI: 10.4137/GBI.S4214
Abstract: A lectin was purified from the hemolymph of esturarine crab Scylla serrata by successive 40% (NH4)2SO4 precipitation, affinity chromatography on asialo fetuin- Sepharose column, Resource Q anion-exchanger in FPLC system and designated as scyllin-2. Scyllin-2 was a homogeneous monomeric protein of molecular mass 75 kD judged by SDS-PAGE and confirmed by ESI-MS-Q-ToF. Its activity was Ca+2 dependent being maximum at pH 7.5 and at 20 °C. N-terminal sequence of scyllin-2 showed close resemblance to peanut lectin and histidine kinase A. It agglutinated human O, A, B and AB blood group erythrocytes equally well and showed maxi- mum inhibition with α-Gal by hapten-inhibition study. The detailed carbohydrate specificity of scyllin-2 was determined at the macro-molecular level based on the Gal/GalNAc structural units in the mammalian glycoproteins by enzyme-linked lectinosorbent (ELLSA) and inhibition assays. It revealed that scyllin-2 binds specifically to tumor-associated carbohydrate antigens GalNAcα1→Ser/Thr (Tn) and Galβ1→3GalNAcα1→Ser/Thr (Tα). It showed very weak binding with Galβ1→3/4GlcNAc (I/II) glycotopes on glycoproteins and T/Tn covered by sialic acid. Multivalancy of Tn/Tα containing glycoproteins tested resulted in higher binding of 102–104 order than the respective Gal and GalNAc monomer. Scyllin-2 stimulated proliferation of mouse splenocytes. Analysis of expression of receptors for scyllin-2 on HepG2 by flow cytometry showed the binding of FITC-scyllin-2 to HepG2 was 86.51%, which was nearly comparable to Artocarpus lakoocha agglutinin (ALA) (66.41%), another Tn/Tα specific lectin indicating that the glycan structure on HepG2 cell surface shows prevalence of Tn/Tα units. It inhibited proliferation of HepG2 cells (61 μg/ml). The inhibitory effect was comparable to ALA (80 μg/ml). Thus, we have characterized a Tn/T specific invertebrate lectin with biological significance.
Correlating the interstellar magnetic field with protostellar jets and its sources
Cristiane G. Targon,Claudia V. Rodrigues,Adriano H. Cerqueira,Gabriel R. Hickel
Physics , 2011, DOI: 10.1088/0004-637X/743/1/54
Abstract: This article combines new CCD polarimetric data with previous information about protostellar objects in a search for correlations involving the interstellar magnetic field. Specifically, we carried out an optical polarimetric study of a sample of 28 fields of 10 X 10 arcmin^2 located in the neighborhood of protostellar jets and randomly spread over the Galaxy. The polarimetry of a large number of field stars is used to estimate both the average and dispersion of the interstellar magnetic field (ISMF) direction in each region. The results of the applied statistical tests are as follows. Concerning the alignment between the jet direction and the interstellar magnetic field, the whole sample does not show alignment. There is, however, a statistically significant alignment for objects of Classes 0 and I. Regarding the interstellar magnetic field dispersion, our sample presents values slightly larger for regions containing T Tauri objects than for those harboring younger protostars. Moreover the ISMF dispersion in regions containing high-mass objects tends to be larger than in those including only low-mass protostars. In our sample, the mean interstellar polarization as a function of the average interstellar extinction in a region reaches a maximum value around 3% for A(V) = 5, after which it decreases. Our data also show a clear correlation of the mean value of the interstellar polarization with the dispersion of the interstellar magnetic field: the larger the dispersion, the smaller the polarization. Based on a comparison of our and previous results, we suggest that the dispersion in regions forming stars is larger than in quiescent regions.
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