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A technique to measure the concentration of Penicillium allii conidia in damp chamber experiments by spectrophotometry was developed. A negative linear correlation (R²=0.56) was observed between transmittance at 340 nm and the concentration of P. allii conidia in water agar 0.05%. The equation that relates transmittance (T) with concentration (conidia mL-1) (y) is: y = 9.3 10(6) - 86497 T. The method was assayed by inoculating 43 P. allii strains in two garlic cultivars. The method proved to be more rapid than the traditional use of a hemocytometer with an improved accuracy. The CV of the number of conidia per hemocytometer reticule was of 35.04%, while the transmittance CV was of 2.73%. The extreme values chosen for T were 40 and 80 because the sensitivity of the method decreased when concentrations of conidia were out of this range.

Fusarium basal rot (FBR), which is caused predominantly by Fusarium oxysporum and F. proliferatum, is the main limiting factor of onion crops. Resistant cultivars obtained in other countries do not behave as such in Argentina crop fields. The cultivars Antártica-INTA, Grano de Oro-Seminis, Valcatorce-INTA and TW-2007 (reported as tolerant) were tested with five Fusarium spp. isolates, using four inoculum concentrations. Disease incidence was recorded along 28 days and the area under disease progress curve was calculated. Diverse epidemiological models were fitted to experimental data. There were significant differences in the resistance level among cultivars, with TW-2007 being the most tolerant. Local Fusarium isolates were the most virulent ones. The concentration of 10,000 microconidia/ gram was the most lethal for all isolates. The absence of resistance to Fusarium in the four cultivars tested was confirmed. Inoculum concentration and isolate are critical factors in screening for resistance to FBR. Breeding based on the selection of genotypes against low virulence strains of Fusarium spp. and the presence of more aggressive strains in local fields may be one of the causes why varieties reported as resistant or tolerant behave as susceptible in our environment.

The use of a Neubauer chamber is a broadly employed method when cell suspensions need to be quantified. However, this technique may take a long time and needs trained personnel. Spectrophotometry has proved to be a rapid, simple and accurate method to estimate the concentration of spore suspensions of isolates of the genus Fusarium. In this work we present a linear formula to relate absorbance measurements at 530 nm with the number of microconidia/ml in a suspension.

Penicillium sect. Chrysogena was introduced by Frisvad & Samson (2004) for species having ter-or quarterverticillate branched conidiophores, relatively short phialides (< 10 µm) and smooth to finely roughened conidia. Four series and eight species (P. aethiopicum, P. chrysogenum, P. confertum, P. di podomyis, P. flavigenum, P. mononematosum, P. nalgiovense and P. persicinum) were accepted in this section. Only species lacking a sexual state were included, but a close affinity with Eupenicillium egyptiacum was suggested. Recently, single name nomenclature was applied in Penicillium and both asexual and sexual reproducing species were included in the redefined genus (Houbraken & Samson 2011). Using a multigene approach, Penicillium was divided into 25 sections and sect. Chrysogena was expanded to include species with a sexual state (P. egyptiacum, P. kewense, P. molle and P. sinaicum), and the recently resurrected species P. rubens. With the exception of P. chrysogenum, P. nal giovense and P. rubens, the species of sect. Chrysogena are primary soilborne (Frisvad & Samson 2004). Penicillium chrysogenum (and P. rubens) garner much research interest because of health ramifications that are a consequence of their occurrence in various food products (Pitt & Hocking 2009, Samson et al. 2010) and indoor environments, including damp building materials, indoor air and dust (

A total of 147 samples of garlic (Allium sativum) bulbs affected by blue mould were obtained from a variety of agroclimatic districts between December 1999 and February 2000. Penicillium species were identified using both morphological and chemotaxonomic characteristics. Penicillium allii was the predominant species isolated (81·8%) in this survey and the only species proven to be pathogenic on garlic. Other species were isolated much less frequently: P. chrysogenum (13·7%), P. brevicompactum (2·8%), P. phoeniceum (0·9%), P. aurantiogriseum (0·6%) and P. flavigenum (0·2%). Colonies of P. allii could be classified into four morphotypes and their distribution seemed to be influenced by seed trade and agricultural practices. Penicillium allii isolates were grouped into three aggressiveness phenotypes (low, medium and high) based on their ability to cause disease during field trials on susceptible (Fuego INTA) and less susceptible (Castaño INTA) garlic cultivars. The number of surviving plants at 191 days after planting and postharvest bulb weight contributed the most towards aggressiveness modelling.

Fifteen strains representing each Penicillium ser. Corymbifera taxa were compared using phenotypic and chemotaxonomic characters by cluster analysis and discriminant partial least squares regression. Variability in phenotypic expression of species strains resulted in a more fragmented classification compared with secondary metabolite expression. Although the observed phenotypic expression varied for strains cultured upon the same media, it was possible to classify strains into species groupings based only upon a few distinctive phenotypic traits. Data analysis of secondary metabolite profiles generated from HPLC-diode array dectection analysis gave reliable strain classification when more than one media type was employed. Depending on the species, Czapek yeast autolysate agar typically yielded the greatest chemical diversity; however, several metabolites (terrestric acid, corymbiferone, the corymbiferan lactones, and daldinin D) were only produced when strains were grown on either y...

In this work the effect of time on in vitro culture of seed traces is evaluated. Without changing media, there was no decline in the number of rescued embryos for any cross within and up to 210 d of culture. After that period a decline was shown for varieties producing abundant callus from the external tegument. Direct germination of embryos increased in all crosses except for Blush Seedless x 73049, which stopped direct germination after 90 d. The polyembryony was advantageous for the cross Superior Seedless x Dawn Seedless, because it increased the percentage of normal plantlets. Multiple embryos showed a higher capacity to germinate in all cases. More embryos were obtained by excision and they presented a higher percentage of normal plantlets in comparison to plantlets obtained by embryos germinated directly. Embryos from the varieties Ruby Seedless, Blush Seedless and Bronx Seedless mainly produced normal plantlets while Crimson Seedless, Superior Seedless and Fantasy Seedless e...

In this work the effect of time on in vitro culture of seed traces is evaluated. Without changing media, there was no decline in the number of rescued embryos for any cross within and up to 210 d of culture. After that period a decline was shown for varieties producing abundant callus from the external tegument. Direct germination of embryos increased in all crosses except for Blush Seedless x 73049, which stopped direct germination after 90 d. The polyembryony was advantageous for the cross Superior Seedless x Dawn Seedless, because it increased the percentage of normal plantlets. Multiple embryos showed a higher capacity to germinate in all cases. More embryos were obtained by excision and they presented a higher percentage of normal plantlets in comparison to plantlets obtained by embryos germinated directly. Embryos from the varieties Ruby Seedless, Blush Seedless and Bronx Seedless mainly produced normal plantlets while Crimson Seedless, Superior Seedless and Fantasy Seedless e...

El núcleo más profundo de cada constitución espiritual se manifiesta en cuanto el movimiento del pensamiento, el inquieto preguntar acerca del significado, del origen, del fundamento de lo real y de lo pensado, ha arribado a un concepto ante el cual todas aquellas preguntas ya no son dirigidas. En la representación de lo individual, del círculo, de la época cultural descansa, más o menos claramente, un concepto tal, hacia el cual van todos los caminos de pensamiento como si buscaran primero en él su orientación, en tanto que él mismo, evidente por antonomasia, no necesitaría fundamentación y es apto. Puesto que es la expresión del correspondiente modo y direccionalidad de la naturaleza espiritual que lo encuentra como hecho último que no puede demostrarse porque no puede refutarse. Estos conceptos básicos no fundamentados son los puntos en los que el pensamiento y el ser del individuo pensante se encuentran. Así mostraba el espíritu griego su estructura en la idea de sustancia, de una esencia inmutable, fija, y de sus formas. La tarea del pensamiento parecía resuelta con la reducción de los fenómenos a un invariable atemporal, sin que se preguntara a este último por su legitimación. La veneración de la forma plástica, tal como se adecuó a ese espíritu, en su incomparable unidad de racionalismo y genio artístico, es el símbolo de cómo aquí el concepto de ser sustancial y de sus formas eternas se tornó la incuestionabilidad definitiva de la imagen de mundo. En este lugar puso el cristianismo el concepto de Dios y del orden de las cosas fijado por Dios. Aquí dejo en suspenso cuánto de aquellos conceptos básicos griegos seguía operando en ello. En todo caso, el concepto en el cual el preguntar acaba, dentro de la concepción cristiana de mundo, ha albergado en sí un quantum mayor de vida que el concepto de ser griego. Luego, con el fin del Renacimiento, se destacó otro concepto como el último: la naturaleza y las leyes de su movimiento mecánico. Ahora la verdadera realidad ya no es la pura y simplemente fija, granítica, eternidad del ser, como en los griegos y, propiamente, también en el concepto de Dios, sino una realidad a cada instante modificada, y así son ahora las leyes de estos cambios lo definitivo, lo-que-todo-decide. Ya no puede preguntarse más de dónde provienen las mismas; y si se derivan de la voluntad o de la esencia de Dios es algo que no está fundado ya en la estructura de aquellos conceptos mismos, sino que procede de un planteamiento del problema ahora solamente transmitido y por principio distinto. Ahora, sin embargo, con el siglo xx, el movimiento mecánico parece ceder a otro concepto su lugar como última instancia: a la vida. Entre la eternidad metafísica de la sustancia como el concepto básico ya no fundamentable y el concepto moderno de vida se manifiesta el movimiento mecánico * Los textos publicados en esta revista están sujetos -si no se indica lo contrario-a una licencia de Reconocimiento 3.0 España de Creative Commons. Puede copiarlos, distribuirlos, comunicarlos públicamente, hacer obras derivadas y usos comerciales siempre que reconozca los créditos de las obras (autoría, nombre de la revista, institución editora) de la manera especificada por los autores o por la revista. La licencia completa se puede consultar en

In the following interview, the sociologist Laymert Garcia dos Santos discusses his intellectual trajectory. The highlight is the subject about which he has been writing in recent times: the question of the "future of the human". Here, this point is discussed against the framework of its philosophical implications and of the debate concerning politics and technology. Members of the group "Knowledge, Technology and Market", which Santos coordinates, carried out the interview.

The aim of this article is to analyze Günther Anders and Gilbert Simondon's central theses on technology. Departing from a brief systematization of the authors' perspectives, it approaches the problem of technologies as a constituent feature of the human condition. This proposal is developed on the basis of Anders’s master work, The Outdatedness of Human Beings. This paper argues that the transformation of the world of technical artifacts tends to do away with the machine as an individualized unit, which becomes itself a system of relations and extends far beyond the work process. The implications of this trend in the logics of scientific discovery are also addressed in these pages.

This article provides a description of a search engine, not as an informational tool, but as a socio-technical device. In order to map the milieu where that device takes form, we analyze a scientific paper about Google and the patent where the method known as PageRank is documented. We problematize a particular kind of relation with technology, by posing the following questions: what is being taken for granted in those techniques? How is the "government" of persons and things thought? How does the market drive the design of those systems? This text aims to contribute to the researches about human-machine relations, tracing, in particular, some re-configurations of technique and language.

Drawing from some few examples, this text analyses narratives on information and communication technologies as figurations of movements of people and movements of data. It also examines alternative researches on the relation between scientific and technological development and social change. The first example is that of communications networks engineering. A second group of examples concerns the modes of professional legitimation of software developers; specially, engineering groups that produce internet protocols. As part of an ongoing research on neoliberal political rationalities and their effects, we inquiry how fields of knowledge and production are being redefined by time-spaces of software.

Este texto analiza, a partir de algunos pocos ejemplos, narrativas sobre las tecnologías de información y comunicación como representaciones del movimiento de personas y de datos. Examina también perspectivas teóricas alternativas en torno a la relación entre desarrollo científico-técnico y cambio social. El primer ejemplo es el de la ingeniería de redes de comunicaciones; un segundo grupo de ejemplos, concierne a los modos de legitimación profesional de desarrolladores de software, en especial, grupos de ingeniería que producen protocolos para Internet. Como parte de una investigación en curso sobre las racionalidades políticas neoliberales y sus implicaciones, indaga cómo campos de saber son redefinidos por los espacios-tiempos del software.