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Search Results: 1 - 10 of 432718 matches for " Maria Luisa P.N.;Fajardo "
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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.
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.
Differentially expressed stress-related genes in the compatible citrus-Citrus leprosis virus interaction
Freitas-Astúa, Juliana;Bastianel, Marinês;Locali-Fabris, Eliane C.;Novelli, Valdenice M.;Silva-Pinhati, Ana Carla;Basílio-Palmieri, Ana Carolina;Targon, Maria Luisa P.N.;Machado, Marcos A.;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500026
Abstract: leprosis, caused by citrus leprosis virus, cytoplasmic type (cilv-c), is the main viral disease in the brazilian citrus industry. this occurs because of the widespread source of inoculum and the year-round presence of the vector, the tenuipalpid mite brevipalpus phoenicis, in citrus plants. in addition, while some citrus species are resistant to cilv-c, c. sinensis, the main cultivated species in the country, is extremely susceptible to the disease. the main objective of this work was to identify genes in c. sinensis cv. pêra plants that were differentially expressed after the host was challenged with cilv-c. in order to accomplish that, cdna libraries were constructed from healthy and cilv-inoculated sweet orange leaves. two hundred and fifty-four genes were found to differ significantly in terms of expression, with 193 of them induced and 61 repressed after inoculation. here we discuss the possible roles of a sub-set of these genes involved in metabolism, energy, signaling and cell rescue, defense and virulence, and indicate which kind of response may take place in the initial steps of the disease. although the symptoms induced by cilv-c in its compatible interaction with sweet orange resemble those of hypersensitive response (hr) in incompatible interactions, our data indicate that, apparently, the manifestation of leprosis symptoms should not be considered hr.
PR gene families of citrus: their organ specific-biotic and abiotic inducible expression profiles based on ESTs approach
Campos, Magnólia A.;Rosa, Daniel D.;Teixeira, Juliana érika C.;Targon, Maria Luisa P.N.;Souza, Alessandra A.;Paiva, Luciano V.;Stach-Machado, Dagmar R.;Machado, Marcos A.;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500020
Abstract: in silico expression profiles, of the discovered 3,103 citrus ests putatively encoding for pr protein families (pr-1 to pr-17), were evaluated using the brazil citrus genome est citest/database. hierarchical clustering was displayed to identify similarities in expression patterns among citrus pr-like gene families (prlgf) in 33 selected cdna libraries. in this way, prlgf preferentially expressed by organ and citrus species, and library conditions were highlighted. changes in expression profiles of clusters for each of the 17 prlgf expressed in organs infected by pathogens or drought-stressed citrus species were displayed for relative suppression or induction gene expression in relation to the counterpart control. overall, few prlgf showed expression 2-fold higher in pathogen-infected than in uninfected organs, even though the differential expression profiles displayed have been quite diverse among studied species and organs. furthermore, an insight into some contigs from four prlgf pointed out putative members of multigene families. they appear to be evolutionarily conserved within citrus species and/or organ- or stress-specifically expressed. our results represent a starting point regarding the extent of expression pattern differences underlying prlgf expression and reveal genes that may prove to be useful in studies regarding biotechnological approaches or citrus resistance markers.
In silico analysis of phytohormone metabolism and communication pathways in citrus transcriptome
Quecini, Vera;Torres, Gisele A.M.;Rosa Jr, Vicente E. de;Gimenes, Marcos A.;Machado, Jeanne B. de M.;Figueira, Antonio V. de O.;Benedito, Vagner;Targon, Maria Luisa P.N.;Cristofani-Yaly, Mariangela;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500002
Abstract: plant hormones play a crucial role in integrating endogenous and exogenous signals and in determining developmental responses to form the plant body throughout its life cycle. in citrus species, several economically important processes are controlled by phytohormones, including seed germination, secondary growth, fruit abscission and ripening. integrative genomics is a powerful tool for linking newly researched organisms, such as tropical woody species, to functional studies already carried out on established model organisms. based on gene orthology analyses and expression patterns, we searched the citrus genome sequencing consortium (citest) database for expressed sequence tags (est) consensus sequences sharing similarity to known components of hormone metabolism and signaling pathways in model species. more than 600 homologs of functionally characterized hormone metabolism and signal transduction members from model species were identified in citrus, allowing us to propose a framework for phytohormone signaling mechanisms in citrus. a number of components from hormone-related metabolic pathways were absent in citrus, suggesting the presence of distinct metabolic pathways. our results demonstrated the power of comparative genomics between model systems and economically important crop species to elucidate several aspects of plant physiology and metabolism.
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.
The Influence of Heat-Treated Sheep Droppings on the Performance, Carcass Characteristics and Economics of Production of Starter Broilers
P.N. Onu
Journal of Animal and Veterinary Advances , 2012,
Abstract: The goal of this study was to determine the influence of Heat-treated Sheep Droppings (HSD) on the performance, carcass characteristics and economics of production of starter broilers. One hundred and sixty eight, 7-days old Anak 2000 broiler chicks were randomly allocated to 4 dietary treatments in three replicates of14 birds each. Four broiler starter diets were formulated such that HSD were fed at 0, 5, 10 and 15% inclusion levels. The experimental period lasted from 7-35 days of age. Growth performance, carcass characteristics and economics of production were studied. Results showed that the proximate analysis indicated that HSD contains reasonable amounts of protein, ether extract, nitrogen free extract and ash as well as high amount of fibre. There was a significant) increase in feed intake with increase in dietary level of HSD. There was a significant depression of weight gain and protein efficiency ratio at 15% HSD inclusion level while the weight gain and protein efficiency ratio of bird fed 5 and 10% HSD diets were not at variance with those fed 0% diet. The feed conversion ratio of the birds depreciated significantly at 10 and 15% HSD dietary levels. The carcass parts expressed as percentages of live weight were not significantly influenced by the treatments except for the gizzard, which had significantly high values in birds fed diets 3 and 4. HSD inclusion at 10% proved more advantageous in terms of feed cost per kg of live broiler and in percentage cost saving. It is concluded from the result of this study that HSD is a potential feedstuff in broiler starter feeding at up to 10% dietary level beyond depression of growth occurs.
The Post-Marcos Regime, The Non-Bourgeois Opposition and the Prospects of a Philippine "October"
P.N. Abinales
Kasarinlan : Philippine Journal of Third World Studies , 1985,
Abstract: The rebellion that ousted Marcos combined massive civilian support with a military revolt. This gave rise to a reconstituted bourgeois liberal democratic State involving the emergence of new political forces hitherto marginal to the anti-Marcos opposition and the relative isolation of the Philippine Left from the political mainstream. This new political situation is set in a backdrop of economic crisis and bleak prospects for social recovery. The forces committed to social and class-based change remain disunited, and the revolutionary vanguard suffers from a “crisis of imagination” and an inadequate strategy of resistance. The paper argues that the “February Revolution” has only changed the mode of political governance but not necessarily the political economy of the country. The present is only an interregnum which may either slide back to pre-Marcos conditions or create new ones that will facilitate at a future date the occurrence of a Philippine “October”.
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