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Search Results: 1 - 10 of 201815 matches for " Brito Nélida "
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The Botrytis cinerea xylanase Xyn11A contributes to virulence with its necrotizing activity, not with its catalytic activity
Judith Noda, Nélida Brito, Celedonio González
BMC Plant Biology , 2010, DOI: 10.1186/1471-2229-10-38
Abstract: We show here that Xyn11A has necrotizing activity on plants and that this capacity is conserved in site-directed mutants of the protein lacking the catalytic activity. Besides, Xyn11A contributes to the infection process with the necrotizing and not with the xylan hydrolyzing activity, as the catalytically-impaired Xyn11A variants were able to complement the lower virulence of the xyn11A mutant. The necrotizing activity was mapped to a 30-amino acids peptide in the protein surface, and this region was also shown to mediate binding to tobacco spheroplasts by itself.The main contribution of the xylanase Xyn11A to the infection process of B. cinerea is to induce necrosis of the infected plant tissue. A conserved 30-amino acids region on the enzyme surface, away from the xylanase active site, is responsible for this effect and mediates binding to plant cells.Botrytis cinerea is a phytopathogenic fungus with a wide host range and a necrotrophic life style (for a review see [1-3]). As part of its invasion strategy, B. cinerea and other necrotrophs are thought to promote programmed cell death (PCD), or apoptosis, in plant cells surrounding the lesion by making use of the plant defence response known as the hypersensitive response (HR) [4]. HR comprises a range of effects triggered by pathogens that culminate in PCD of the plant cells around the infected area [5]. It is an effective defence against biotrophs, preventing the progression of the infection, but it has been suggested that HR can be exploited by necrotrophs, such as B. cinerea, for its own benefit [1-4]. The basic idea is that necrotrophs produce signals able to induce plant cells to kill themselves and then grow on the dead tissue.Several B. cinerea derived metabolites and proteins have been shown to cause cellular death when applied to plant cells or tissues, like the small compounds botrydial and botcinolide [6], Oxalic acid [2,7], enzymes with endopolygalacturonase activity [8] and Nep1-like proteins (NLPs) [
High abundance of Serine/Threonine-rich regions predicted to be hyper-O-glycosylated in the secretory proteins coded by eight fungal genomes
González Mario,Brito Nélida,González Celedonio
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-213
Abstract: Background O-glycosylation of secretory proteins has been found to be an important factor in fungal biology and virulence. It consists in the addition of short glycosidic chains to Ser or Thr residues in the protein backbone via O-glycosidic bonds. Secretory proteins in fungi frequently display Ser/Thr rich regions that could be sites of extensive O-glycosylation. We have analyzed in silico the complete sets of putatively secretory proteins coded by eight fungal genomes (Botrytis cinerea, Magnaporthe grisea, Sclerotinia sclerotiorum, Ustilago maydis, Aspergillus nidulans, Neurospora crassa, Trichoderma reesei, and Saccharomyces cerevisiae) in search of Ser/Thr-rich regions as well as regions predicted to be highly O-glycosylated by NetOGlyc (http://www.cbs.dtu.dk). Results By comparison with experimental data, NetOGlyc was found to overestimate the number of O-glycosylation sites in fungi by a factor of 1.5, but to be quite reliable in the prediction of highly O-glycosylated regions. About half of secretory proteins have at least one Ser/Thr-rich region, with a Ser/Thr content of at least 40% over an average length of 40 amino acids. Most secretory proteins in filamentous fungi were predicted to be O-glycosylated, sometimes in dozens or even hundreds of sites. Residues predicted to be O-glycosylated have a tendency to be grouped together forming hyper-O-glycosylated regions of varying length. Conclusions About one fourth of secretory fungal proteins were predicted to have at least one hyper-O-glycosylated region, which consists of 45 amino acids on average and displays at least one O-glycosylated Ser or Thr every four residues. These putative highly O-glycosylated regions can be found anywhere along the proteins but have a slight tendency to be at either one of the two ends.
Botrytis cinerea Protein O-Mannosyltransferases Play Critical Roles in Morphogenesis, Growth, and Virulence
Mario González, Nélida Brito, Marcos Frías, Celedonio González
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0065924
Abstract: Protein O-glycosylation is crucial in determining the structure and function of numerous secreted and membrane-bound proteins. In fungi, this process begins with the addition of a mannose residue by protein O-mannosyltransferases (PMTs) in the lumen side of the ER membrane. We have generated mutants of the three Botrytis cinerea pmt genes to study their role in the virulence of this wide-range plant pathogen. B. cinerea PMTs, especially PMT2, are critical for the stability of the cell wall and are necessary for sporulation and for the generation of the extracellular matrix. PMTs are also individually required for full virulence in a variety of hosts, with a special role in the penetration of intact plant leaves. The most significant case is that of grapevine leaves, whose penetration requires the three functional PMTs. Furthermore, PMT2 also contributes significantly to fungal adherence on grapevine and tobacco leaves. Analysis of extracellular and membrane proteins showed significant changes in the pattern of protein secretion and glycosylation by the pmt mutants, and allowed the identification of new protein substrates putatively glycosylated by specific PMTs. Since plants do no possess these enzymes, PMTs constitute a promising target in the development of novel control strategies against B. cinerea.
Aportes al estudio de la integridad del sitio Laguna La Barrancosa 1 (partido de Benito Juárez, provincia de Buenos Aires): análisis textural y distribucional de los microdesechos líticos
Pal,Nélida;
Intersecciones en antropolog?-a , 2008,
Abstract: in this paper the results obtained from microdebitage analysis of laguna la barrancosa 1 site are presented. the main objective is to contribute to the study of site integrity starting from the identification of the cultural and natural processes that took part in its formation. in order to fulfill this objective, the study of the spatial distribution and textural analysis of the microdebitage were carried out, subsequently combining them with stratigraphic and sedimentological approaches. the analysis of vertical distribution showed a scarce dispersion of lithic and bone materials without a strong distribution by size. however, the study of horizontal distribution allowed lithic concentrations in specific places of the site to be identified. the textural analysis of the lithic assemblage (microdebitage, macrodebitage and tools) proved that roots were the main agent affecting the lithic surfaces; edge and ridge rounding was also observed in the studied assemblages, probably as a result of cultural activities (e.g., platform preparation). hence, these results suggest that natural formation processes would not have significantly affected the site integrity.
Hacia una caracterización del componente experiencial en el discurso narrativo dirigido a ni?os
León,élida;
Letras , 2009,
Abstract: the present study attempts a characterization of the short story written for children with special attention on discourse itself and its linguistic construction. it is supported on statements of labov and waletzky (1967) and labov (1972), as well as the fundamentals of systemic-functional grammar as developed by martin et al (1997). an exploratory study was designed of a sample of 10 short stories collected from school textbooks for basic education. results indicate that the stories analyzed have a macro-structure which is similar to that of oral narratives of personal experience. the elements orientation, complication, evaluation and resolution became evident in all the stories of the sample. also, we found predominance of material and verbalization processes, which suggests that speech is as relevant as action. finally, an important consistency was found between the types of clausal processes and their grouping in functional sections of the narration.
Certeza y posiciones de poder de algunos personajes en cuentos escritos para ni?os
León,élida;
Letras , 2007,
Abstract: the aim of this study was to analyze the realization of certainty in relation to power stances of characters in a sample of children?s short stories. to do so, a descriptive study of six children?s stories was developed on the basis of qualitative procedures. in the light of systemic functional linguistics, specifically simpson?s (1993) model of modality, utterances with elements that indicated some degree of certainty were identified and classified. in this way, possible connections between power stances and degrees of epistemic modality, as well as categorical assertions in characters? direct speech, were established. the results suggest that +power stances are more associated to high degrees of certainty; -power stances seem to be related to median and low degrees rather than to high degrees of epistemic modality.
?Dilemas?: metodológicos y éticos en la investigación antropológica en Servicios de salud
Barber,Nélida Alicia;
Av?? , 2009,
Abstract: in this paper we examine some particularities of anthropological research in hospitality institutions, on the basis of fieldwork carries out in hospitals of the metropolitan and suburban areas of buenos aires. on one side, we focus on the institutional requirements for allowing access to the hospital and, on the other side, on the emotional and ethical commitments of researchers. in what concern to the former, we discuss the problematic arising from procuring authorization from the ethical research committee of the hospital to conduct a research in these premises. on the other hand, we discuss some ethic problems and dilemmas and we analyze the methodological and theoretical implications of such issues.
Mujer y matrimonio en San Miguel de Tucumán desde la temprana colonización hasta mediados del siglo XVIII
Robledo,Nélida Beatriz;
Cuadernos de la Facultad de Humanidades y Ciencias Sociales. Universidad Nacional de Jujuy , 2000,
Abstract: the objective of this paper is to show the condition of spanish women in san miguel de tucuman through the marriage institution, between the foundation of san miguel in ibatin until the middle of the xviii century, when there appear the first sing of women trying to look for o their own space and their own defense. women′s role is analysed, considering the economic aspect, expressed in their dowery, as well as the ceremonial aspect through the different stages of the matrimonial pact. the lack of women′s autonomy is studied as well as their subjection to the state protection. the governors′ policy that determined women′s situation when helping them to get their dowery and also to get married. this meant to offer them protection but it also implied a degree of manipulation. fathers and husbands had an unlimited authority over their daughters and wives. considering this frame, women them selves looked for support and security from their male relatives, and the state itself as well as the church. women outside the marriage system have also been considered, marriage annulment and extra-matrimony situations: cohabitation and adultery, in the same way that the state made an effort to put the social structure in order, based on the protection of the family ties.
Tipos de reprodu??o e desenvolvimento de algumas espécies brasileiras de Ixodorrhynchidae (Acarina)
Lizaso, Nélida M.;
Revista Brasileira de Zoologia , 1988, DOI: 10.1590/S0101-81751988000300004
Abstract: two kinds of reproduction in the ixodorrhynchidae were ob-served: oviparous, in ophiogongylus lizaso, 1983, and ovoviviparous, in ixobioides fonseca, 1934 and chironobius lizaso, 1983. descriptions of the immature stages and biological data are given.
Levantamento da fauna acarológica ectoparasita de serpentes n?o venenosas do Estado de S?o Paulo
Lizaso, Nélida M.;
Revista Brasileira de Zoologia , 1982, DOI: 10.1590/S0101-81751982000300010
Abstract: the ectoparasitic mite fauna of non-poisonous snakes from the estado de s?o paulo was surveyed during the period of march, 1976 to september, 1979. considerations are made about the systematics and ecology of the genera studied. a total of 1969 snakes belonging to 30 genera was examined. this study also includes data on multiple parasitism, diversity of the mite fauna, abundance of each genera of mite, for the 4 families and 7 genera of mites.
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