ABSTRACT
Este ensaio objetiva discutir aspectos psicossociais que configuram um campo relacional com os alimentos e os processos associados ao cultivo, produção, comercialização, preparo e consumo alimentar. Comer na sociedade contemporânea é um fazer complexo: a escolha do que consumir está culturalmente orientada por processos políticos/tecnológicos/afetivos que se expressam na sociedade global. Neste contexto, é fundamental ter em conta os atravessamentos do capitalismo contemporâneo e sua parcela nas condições de produção subjetiva que, no campo potencialmente interdisciplinar da alimentação, se mostra para além de uma interpretação da nutrição pela égide do biológico.
This essay aims to discuss psychosocial aspects that shape a relational field with foods and processes associated with cultivation, production, commercialization, preparation and food consumption. Eating in contemporary society is a complex doing: choosing what to consume is culturally oriented by political / technological / affective processes that express themselves in the global society. In this context, it is fundamental to take into account the crossings of contemporary capitalism and its share in the conditions of subjective production that, in the potentially interdisciplinary field of food, shows beyond an interpretation of nutrition by the aegis of the biological.
Este ensayo objetiva discutir aspectos psicosociales que configuran un campo relacional con los alimentos y los procesos asociados al cultivo, producción, comercialización, preparación y consumo alimentario. Comer en la sociedad contemporánea es un hacer complejo: la elección de lo que consumir está culturalmente orientada por procesos políticos / tecnológicos / afectivos que se expresan en la sociedad global. En este contexto, es fundamental tener en cuenta los efectos del capitalismo contemporáneo y su parcela en las condiciones de producción subjetiva que, en el campo potencialmente interdisciplinario de la alimentación, se muestra más allá de una interpretación de la nutrición por la égida de lo biológico.
Cet essai a pour but de discuter des aspects psychosociaux qui façonnent un champ relationnel avec les aliments et les processus associés à la culture, à la production, à la commercialisation, à la préparation et à la consommation d'aliments. Manger dans la société contemporaine est une tâche complexe: choisir ce qu'il faut consommer est culturellement orienté par des processus politiques / technologiques / affectifs qui s'expriment dans la société mondiale. Dans ce contexte, il est fondamental de prendre en compte les croisements du capitalisme contemporain et sa part dans les conditions de la production subjective qui, dans le domaine potentiellement interdisciplinaire de l'alimentation, montre audelà d'une interprétation de la nutrition par l'égide du biologique.
ABSTRACT
Background: Nowadays, leaching-ore bacteria, especially Acidithiobacillus ferrooxidans is widely used to retrieve heavy metals, many researches reflected that extra adding microorganism could promote bioleaching efficiency by different mechanisms, but few of them discussed the interaction between microorganisms and based on growth model. This study aimed to provide theoretical support for the collaborative bioleaching of multiple microorganisms by using the Lotka-Volterra (L-V) model. Results: This study investigated the interaction of Acidithiobacillus ferrooxidans, Rhizobium phaseoli,and Rhodotorula sp. Results showed that the individual growth of the three microorganisms fit the logistic curves. The environmental capacities of A. ferrooxidans, R. phaseoli, and Rhodotorula sp. were 1.88 x 109, 3.26 x 108, and 2.66 x 108 cells/mL, respectively. Co-bioleaching showed mutualism between A. ferrooxidans and R. phaseoli with mutualism coefficients of a =1.19and /3 = 0.31, respectively. The relationship between A. ferrooxidans and Rhodotorula sp. could be considered as commensalism. The commensalism coefficient y of the effect of Rhodotorula sp. on A. ferrooxidans was 2.45. The concentrations of A. ferrooxidans and R. phaseoli were 3.59 x 109 and 1.44 x 109 cells/mL in group E, respectively, as predicted by the model. The concentrations of A. ferrooxidans and Rhodotorula sp. were 2.38 x 109 and 2.66 x 108 cells/mL, respectively. The experimental peak values of the concentrations in microorganism groups E and F were detected on different days, but were quite close to the predicted values. Conclusion: The relationship among microorganisms during leaching could be described appropriately by Lotka-Volterra model between the initial and peak values. The relationship of A. ferrooxidans and R. phaseoli could be considered as mutualism, whereas, the relationship of A. ferrooxidans and R. phaseoli could be considered as commensalism.
Subject(s)
Rhodotorula/growth & development , Acidithiobacillus/growth & development , Rhizobium phaseoli/growth & development , SymbiosisABSTRACT
First record of larvae of Chironomidae (Insecta, Diptera) as prey of Temnocephala sp. (Platyhelminthes, Temnocephalidae), an ectosymbiont on larvae of Corydalidae (Megaloptera). This study constitutes the first record of Temnocephala Blanchard, an ectosymbiont on Corydalidae, as a possible predator of chironomid larvae. Twenty-eight Corydalidae larvae (Corydalus and Protochauliodes) were examined under stereomicroscopic in search for Temnocephala and Chironomidae larvae, of which five megalopteran larvae had 24 Temnocephala sp. associated. Furthermore, eight of these Temnocephala worms had chironomid larvae in their gut contents, an interaction previously unknown. Gut content analyses revealed Corynoneura as the commonest chironomid, but larvae of Larsia, Rheotanytarsus and Tanytarsus were recorded as well. This study included Corydalus and Protochauliodes as hosts for Temnocephala, which might be important for this worm dispersion and population dynamics.
Primeiro registro de larvas de Chironomidae como presas de Temnocephala sp. (Platyhelminthes, Temnocephalidae), um ectosimbionte de larvas de Corydalidae (Maegaloptera). Este estudo constitui o primeiro registro de Temnocephala Blanchard (Platyhelminthes, Temnocephalidae), um ectosimbionte em larvas de Megaloptera, como um possível predador de larvas de Chironomidae. Vinte e oito larvas de Corydalidae (Corydalus e Protochauliodes) foram examinadas sobre estereomicroscópio na busca por Temnocephala e larvas de Chironomidae, das quais cinco larvas de Megaloptera continham 24 Temnocephala sp. associadas. Além disso, oito Temnocephala possuíam em seu conteúdo estomacal larvas de Chironomidae, uma interação desconhecida anteriormente. A análise do conteúdo estomacal revelou Corynoneura como o quironomídeo mais abundante, e também algumas larvas de Larsia, Rheotanytarsus e Tanytarsus. Este estudo inclui Corydalus e Protochauliodes como hospedeiros de Temnocephala, os quais podem ser importantes para a dispersão e dinâmica populacional desses vermes.
ABSTRACT
Relações simbióticas podem ser interações altamente instáveis. Uma série de fatores pode alterar drasticamente o perfil de uma relação, causando prejuízos ou benefícios ao hospedeiro. Essas mudanças estão intimamente ligadas ao custo/benefício por trás dessas interações. Tais fatos nos levam a questionar quais são as possíveis condições que favorecem o comportamento parasitário, comensal ou mutualista? E em que condições cada estratégia tornam-se mais vantajosas para o simbionte? A bactéria Escherichia coli é um exemplo de simbionte que pode apresentar as três estratégias em único hospedeiro, causando desde graves infecções a benefícios defensivos e nutricionais. Nesse contexto, discutiremos nesse trabalho as características da relação simbiótica entre essa bactéria e o ser humano, demonstrando sua complexidade, abordando os possíveis fatores que atuam como determinantes no perfil da relação e as vantagens e desvantagens de cada estratégia
Symbiotic interactions can be highly unstable. A series of factors can dramatically alter the relationship, leading to costs or benefits to the host. These facts lead us to question: what are the possible conditions that promote parasitism, mutualism or commensalism? And under what conditions does each strategy become more advantageous for the symbiont? The bacterium Escherichia coli is an example of symbiont that may have the three strategies in a single host, it may cause serious infections or defensive and nutritional benefits. In this context, we discuss the characteristics of the symbiotic relationship between this bacterium and human hosts, demonstrating its complexity and addressing the possible factors that act as determinants in the profile of the relationship and the advantages/disadvantages of each strategy
Subject(s)
MedicineABSTRACT
Common myna (Acridotherus tristis) and jungle myna (Acridotherus fuscus) forage in pure and mixed flocks of various sizes in fallow lands. These flocks were often found associated with drongos that forage individually on the insects herded out by the movements of the flocking myna. We report here the benefits and costs of such association to drongos and mynas. Drongos had a tendency to associate with larger (> 21) than smaller (<20) flocks irrespective of the species composition of the flocks. Drongos associated with larger flocks showed increased foraging trips and harvested more insects in a given time than those that were either isolated or were associated with small flocks. The food range of drongos and mynas differed significantly indicating that they do not compete with each other. Thus our results indicate that drongos are benefitted by this association; however this association neither benefits nor costs to the mynas. The association between the drongos and mynas therefore appears to be commensalistic.