Daniela Griselda López

Phytotoxic activity in Flourensia campestris and isolation of (−)-hamanasic acid A as its active principle compound

An aqueous extract from Flourensia campestris (Asteraceae) dry aerial parts showed strong inhibition on the germination and growth of Lactuca sativa. Based on bio-guided chromatographic fractionation of aq. extracts from dry and fresh leaves and spectroscopic means, (-)-hamanasic acid A (7-carboxy-8-hydroxy-1(2), 12(13)-dien-bisabolene (1)) was isolated as the most inhibitory active principle on germination (ECg(50)=2.9 mM) and on root (ECr(50)=1.5 mM)/shoot (ECs(50)=2.0 mM) growth. As measured by GC, and correlated with a simple designed 2D-TLC, compound 1 was distributed throughout the plant, with a remarkably high concentration (1.6%) in the leaves and the inflorescences. At least a quarter of the amount of 1 was found in aqueous extracts suggesting that leaching would be a key route for its release into the environment. By contrast, leaf essential oils (HD) between 0.5 and 1.5 μl ml(-1) did not show herbicidal effects and 1 was not found in them (TLC) nor among volatiles (HS-SPME). Volatile compositions were assessed by GC-FID and GC-MS and led to the identification of 23 compounds (4 monoterpenes and 19 sesquiterpenes) with a wide seasonal (spring-summer%) variation, represented principally by bicyclo-germacrene (37-6%), spathulenol (4-32%), globulol (20-0%), beta-caryophyllene (15-6%), caryophyllene oxide (1-13%) and bicycloelemene (10-1%), respectively. The high amount of 1 in F. campestris together with its feasibility of being extracted with water suggest that (-)-hamanasic acid A is an allelochemical in this species. Species-specific studies must be carried out to evaluate the potential of 1 as a natural herbicidal compound.

Volatiles and Nonvolatiles in Flourensia campestris Griseb. (Asteraceae), How Much Do Capitate Glandular Trichomes Matter?

The distribution and ultrastructure of capitate glandular trichomes (GTs) in Flourensia species (Asteraceae) have been recently elucidated, but their metabolic activity and potential biological function remain unexplored. Selective nonvolatile metabolites from isolated GTs were strikingly similar to those found on leaf surfaces. The phytotoxic allelochemical sesquiterpene (–)‐hamanasic acid A ((–)‐HAA) was the major constituent (ca. 40%) in GTs. Although GTs are quaternary ammonium compounds (QACs)‐accumulating species, glycine betaine was not found in GTs; it was only present in the leaf mesophyll. Two (–)‐HAA accompanying surface secreted products: compounds 4‐hydroxyacetophenone (piceol; 1) and 2‐hydroxy‐5‐methoxyacetophenone (2), which were isolated and fully characterized (GC/MS, NMR), were present in the volatiles found in GTs. The essential oils of fresh leaves revealed ca. 33% monoterpenes, 26% hydrocarbon‐ and 30% oxygenated sesquiterpenes, most of them related to cadinene and bisabolene derivatives. Present results suggest a main role of GTs in determining the volatile and nonvolatile composition of F. campestris leaves. Based on the known activities of the compounds identified, it can be suggested that GTs in F. campestris would play key ecological functions in plant‐pathogen and plant‐plant interactions. In addition, the strikingly high contribution of compounds derived from cadinene and bisabolene pathways, highlights the potential of this species as a source of high‐valued bioproducts.

Alfred Schutz's main contributions to the field of economic reflection

For several decades, contemporary social theory has held a considerable misunderstanding around phenomenologically oriented sociology, which has undermined its heuristic potential and, as a consequence, has pushed its conclusions to a marginal place in current discussions. In contrast, our article aims to recover that hermeneutical framework in order to think economic phenomena such as the economic action and the order of the market processes. It is undeniable that Alfred Schutz’s work provides theoretical and methodological elements for the sociological analysis of the economic world. The linkages between Schutz- ian sociology and economic reflection vary widely, ranging from his formative stage within the context of the Mises Circle to the current recovery of his work by Economic Sociology. Within this framework, the aim of this work is to summarize Schutz’s main contributions to the field of economic reflection. The recovery and systematization of the Schutzian vocabulary -in the interface between sociology and economics- can contribute with new elements not only to think from a theoretical point of view but also to address economic phenomena empirically.

El problema del objetivismo en la producción de conocimiento sociológico: la correspondencia entre Alfred Schutz, Talcott Parsons y Harold Garfinkel

El problema epistemologico del objetivismo en la produccion de conocimiento sociologico confronta al investigador con la pregunta acerca del riesgo que conlleva la sustitucion de la realidad social por las idealidades y las abstracciones creadas por la ciencia. A fin de abordar ese problema, el articulo se propone recuperar, desde una perspectiva hermeneutica, una epistemologia de inspiracion fenomenologica en los textos de Alfred Schutz y de Harold Garfinkel. Para ello se analizan, en primer lugar, los aportes de Schutz en la correspondencia mantenida con Talcott Parsons pues es alli donde el autor discute ampliamente las dificultades por las que atraviesan las ciencias sociales con relacion a la fundamentacion de sus conceptos. En segundo lugar, se revisan acervos bibliograficos ineditos de la obra de Garfinkel quien, interesado por el debate epistemologico entre Schutz y Parsons, retoma ese mismo problema epistemologico. Sostendremos que, a diferencia de Schutz quien propone una salida filosofica que consiste en la articulacion de una ontologia del mundo de la vida, Garfinkel elabora una respuesta de caracter metodologico que apunta a iluminar los razonamientos practicos y las decisiones metodologicas de los investigadores a fin de evitar la sustitucion de la realidad social por las idealidades de la reflexion cientifica.

El problema del objetivismo en la producción de conocimiento sociológico

El problema epistemologico del objetivismo en la produccion de conocimiento sociologico confronta al investigador con la pregunta acerca del riesgo que conlleva la sustitucion de la realidad social por las idealidades y las abstracciones creadas por la ciencia. A fin de abordar ese problema, el articulo se propone recuperar, desde una perspectiva hermeneutica, una epistemologia de inspiracion fenomenologica en los textos de Alfred Schutz y de Harold Garfinkel. Para ello se analizan, en primer lugar, los aportes de Schutz en la correspondencia mantenida con Talcott Parsons pues es alli donde el autor discute ampliamente las dificultades por las que atraviesan las ciencias sociales con relacion a la fundamentacion de sus conceptos. En segundo lugar, se revisan acervos bibliograficos ineditos de la obra de Garfinkel quien, interesado por el debate epistemologico entre Schutz y Parsons, retoma ese mismo problema epistemologico. Sostendremos que, a diferencia de Schutz quien propone una salida filosofica que consiste en la articulacion de una ontologia del mundo de la vida, Garfinkel elabora una respuesta de caracter metodologico que apunta a iluminar los razonamientos practicos y las decisiones metodologicas de los investigadores a fin de evitar la sustitucion de la realidad social por las idealidades de la reflexion cientifica.

The problem of objectivism in the production of sociological knowledge: the correspondence of Alfred Schutz, Talcott Parsons and Harold Garfinkel

El problema epistemologico del objetivismo en la produccion de conocimiento sociologico confronta al investigador con la pregunta acerca del riesgo que conlleva la sustitucion de la realidad social por las idealidades y las abstracciones creadas por la ciencia. A fin de abordar ese problema, el articulo se propone recuperar, desde una perspectiva hermeneutica, una epistemologia de inspiracion fenomenologica en los textos de Alfred Schutz y de Harold Garfinkel. Para ello se analizan, en primer lugar, los aportes de Schutz en la correspondencia mantenida con Talcott Parsons pues es alli donde el autor discute ampliamente las dificultades por las que atraviesan las ciencias sociales con relacion a la fundamentacion de sus conceptos. En segundo lugar, se revisan acervos bibliograficos ineditos de la obra de Garfinkel quien, interesado por el debate epistemologico entre Schutz y Parsons, retoma ese mismo problema epistemologico. Sostendremos que, a diferencia de Schutz quien propone una salida filosofica que consiste en la articulacion de una ontologia del mundo de la vida, Garfinkel elabora una respuesta de caracter metodologico que apunta a iluminar los razonamientos practicos y las decisiones metodologicas de los investigadores a fin de evitar la sustitucion de la realidad social por las idealidades de la reflexion cientifica.

The Emergence of the Political: the Problem of Equality in Everyday Life

The aim of this work is to examine the notion of equality in Alfred Schutz’s work, paying special attention to the emergence of the problem of equality in everyday life. In order to formulate a theory of equality, we will base our analysis on Th omas Luckmann’s (1983) phenomenological considerations, emphasizing the constitutive and constructive dimensions of equality. In doing so, our refl ections will move on two levels, the constitutive and the constructive analysis of intersubjectivity.