Letteratura scientifica selezionata sul tema "Amicalité"

A number of actinobacteria of the genus Gordonia are able to use dibenzothiophene (DBT) and its derivatives as the only source of sulfur, which makes them promising agents for the process of oil biodesulfurization. Actinobacteria assimilate sulfur from condensed thiophenes without breaking the carbon–carbon bonds, using the 4S pathway encoded by the dszABC operon-like structure. The genome of the new dibenzothiophene-degrading hydrocarbon-oxidizing bacterial strain Gordonia amicalis 6-1 was completely sequenced and the genes potentially involved in the pathways of DBT desulfurization, oxidation of alkanes and aromatic compounds, as well as in the osmoprotectant metabolism in strain 6-1 and other members of the genus Gordonia, were analyzed. The genome of G. amicalis strain 6-1 consists of a 5,105,798-bp circular chromosome (67.3% GC content) and an 86,621-bp circular plasmid, pCP86 (65.4% GC content). This paper presents a comparative bioinformatic analysis of complete genomes of strain 6-1 and dibenzothiophene-degrading Gordonia strains 1D and 135 that do not have the dsz operon. The assumption is made about the participation in this process of the region containing the sfnB gene. Genomic analysis supported the results of phenomenological studies of Gordonia strains and the possibility of their application in the bioremediation of oil-contaminated environments and in the purification of oil equipment from oil and asphalt-resin-paraffin deposits.

A soil isolate, strain CC-AB07T, was characterized using a polyphasic approach. This organism had chemotaxonomic and morphological properties consistent with its classification in the genus Gordonia. 16S rRNA gene sequence analysis showed that the novel strain formed a monophyletic branch at the periphery of the evolutionary radiation occupied by the genus Gordonia, its closest neighbours being the type strains of Gordonia alkanivorans, Gordonia amicalis, Gordonia bronchialis, Gordonia desulfuricans, Gordonia polyisoprenivorans and Gordonia rhizosphera. The novel isolate was distinguished from all of these type strains using a range of phenotypic properties and by gyrB gene sequence analysis. It was evident from the genotypic and phenotypic data that strain CC-AB07T should be classified as representing a novel species in the genus Gordonia, for which the name Gordonia soli sp. nov. is proposed. The type strain is CC-AB07T (=BCRC 16810T=DSM 44995T).

La réalité virtuelle se présente comme un outil prometteur pour le traitement de l’anxiété sociale notamment à travers des thérapies d’exposition en réalité virtuelle. Dans ces thérapies, les utilisateurs sont confrontés à des situations stressantes et apprennent progressivement à ajuster leurs réactions affectives. Cela nécessite un certain niveau de stress essentiel à la réussite de l’entraînement. La littérature montre que les applications de réalité virtuelle sont capables de provoquer du stress ; toutefois, la manière dont les concepteurs peuvent contrôler avec précision ce niveau de stress reste floue. Pour répondre à ce problème, nous proposons un modèle décrivant un mécanisme permettant de contrôler le stress durant une évaluation sociale en réalité virtuelle. Ce modèle suggère que le stress est influencé par l’amicalité et la dominance des agents virtuels, et que la présence sociale joue un rôle médiateur dans leur impact sur le stress. Afin de tester ce modèle, nous avons mené trois études expérimentales impliquant 141 participants dans des tâches sociales telles que la prise de parole en public et les entretiens d’embauche. Les résultats montrent que le niveau de stress est impacté par le niveau d’amicalité et de dominance des agents virtuels, toutefois, des analyses supplémentaires sont nécessaires afin remédier aux limitations rencontrées et valider le modèle
Virtual reality has shown promise in treating social anxiety through virtual reality exposure therapies. In these therapies, users are exposed to stressful situations and gradually learn to adjust their affective responses. Exposing users to a stressful but safe environment is crucial for a successful exposure. This requires controlling the level of stress induced by the virtual environments. Literature shows that virtual reality applications are capable of inducing stress; however, it remains unclear how designers can precisely control this level of stress. To address this gap, we propose a model of stress that outlines a mechanism through which stress can be controlled during virtual social evaluation scenarios. The model suggests that users’ stress levels are influenced by the friendliness and dominance levels of the virtual agents, with this effect mediated by the users’ sense of social presence. To test this model, three studies involving 141 participants in social tasks, such as public speaking and job interviews, were conducted. The results indicate that agents’ friendliness and dominance levels influence users’ stress levels, however, further investigations are needed to address the limitations encountered and verify the model

Orientador: Lúcia Regina Durrant
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Biossurfactantes e bioemulsificantes são compostos ativos de superfícies (CAS) produzidos por micro-organismos. Desempenham várias funções biológicas, e sua característica anfifílica, juntamente com baixa toxicidade, biodegradabilidade e resistência a extremos de pH, temperatura e salinidade, tem despertado o interesse para a aplicação dessas moléculas em processos biotecnológicos. Porém, o alto custo aliado à baixa produção ainda são impedimentos para a utilização em larga escala. Os desafios para se implementar a produção são: desenvolvimento de estratégias para tornar a produção economicamente viável e o isolamento de moléculas e microorganismos mais eficientes. Neste trabalho, foi estudada a produção, isolamento, extração e caracterização de um CAS por Gordonia amicalis. O micro-organismo foi cultivado em meio GYP (glucose, extracto de levedura, peptona) por 7 dias, e a extração foi feita por precipitação com sulfato de amônio, que resultou em uma concentração de 0,5 g/L do extrato bruto em meio líquido. O CAS não reduziu significativamente a tensão superficial do meio GYP, e apresentou um balanço hidrofílico-lipofílico (HBL) de caráter lipofílico, apresentando mais emulsões do tipo água em óleo (A/O) do que óleo em água (O/A). A molécula apresentou estabilidade a temperaturas de 25ºC a 100ºC, pH de 2 a 10 e salinidades de 5% a 15% quando cultivado por 7 dias, e foi capaz de modificar a interface água/superfície na análise de ângulo de contato. O extrato de 14 dias apresentou Atividade Emulsificante em 24 horas (AE24) reduzida em temperaturas acima de 50ºC, e ausente em pH ácido e salinidades de 5% e 10%. Análises de Cromatografia de Camada Delgada (CCD) revelaram presença de aminoácidos e açúcares na molécula e a análise do potencial zeta revelou que o CAS é um surfactante aniônico. Nas análises de Espectrometria no Infravermelho com Transformadas de Fourier (IR-TF) foram observados estiramentos indicativos de agrupamentos O-H e C-O, que podem indicar presença de grupos éter ou ésteres. O CAS produzido por Gordonia amicalis em meio sintético GYP mostrou-se um eficiente agente emulsificante, com potencial para aplicações biotecnológicas futuras
Abstract: Biosurfactants and bioemulssifiers are surface active compounds (SACs) produced by microorganisms. They have a wide variety of biological functions. Its amphiphilic characteristic, with low toxicity, biodegradability and resistance to extremes of pH, temperature and salinity, has increased the interest of these molecules for application biotechnological process. However, high costs and low production rates are restrictions to their widespread use. The challenges for implementing production are: developing strategies to turn the production economically feasible and isolating more efficient molecules and microorganisms. In this work, we studied the production, isolation, extraction and characterization of a SAC by a Gordonia amicalis. The microrganism was grown in GYP (Glucose, Yeast extract, Peptone) medium for 7 days, and the isolation was carried out by precipitation with ammonium sulfate, which resulted in 0.5 g / L of crude extract. The SAC did not significantly reduce the surface tension of GYP medium, and showed an hydrophilic-lipophilic balance (HLB) with lipophilic character, showing more water in oil (W/O) emulsions than oil in water (O/W) emulsions. The molecule extracted at 7 days was stable at temperatures ranging from 25 to 100 ° C, pH of 2-10 and salinities of 5-15%, and can modify the water/surface contact by the angle of contact analysis. The 14-day isolated extract showed EA24 reduced at temperatures above 50 ºC, and had no Emulsification Activity in 24 hours (EA24) in acid pH and salinity of 5% and 10%. Thin Layer Chromatography (TLC) analysis revealed the presence of sugars and amino acids in the molecule and the zeta potential analysis revealed the compound is an anionic surfactant. In the Fourier Transformed Infrared Spectrometry (FTIV) it were observed stretches indicatives of O-H and C-O groups, that might indicate ether or ester groups. The SAC produced by Gordonia amicalis in GYP medium proved to be an efficient emulsifier, with potential for biotechnological applications
Mestrado
Ciência de Alimentos
Mestra em Ciência de Alimentos

Gordonia amicalis G2 strain is a potential object for the production of microbial glycolipids using oil refinery wastes. The genome of the G. amicalis G2 strain consists of a ring chromosome and ring plasmids pCP113 and pCP89. Bioinformatic analysis of the genome showed the availability of enzymes involved in the synthesis of fatty acids and trehalose, which form the structure of biosurfactants.