Propriedades tecnológicas e probióticas das bactérias isoladas do queijo do Pico

A secção Biologia é coordenada pelo Professor Universitário Armindo Rodrigues.[…]. A listéria é o agente patogénico responsável pela listeriose, uma infeção rara, mas grave nos seres humanos. Leite e produtos lácteos têm sido implicados na maioria dos surtos relatados de listeriose, embora o tratamento térmico elimine esta bactéria durante o processo de pasteurização. Isto indica que estes produtos podem ser contaminados em fases posteriores de produção. Desta forma, a contaminação do queijo com listéria é um problema recorrente e uma preocupação constante para a indústria dos lacticínios. A utilização de bactérias que possam combater este agente patogénico pode ser uma mais-valia na aplicação a este tipo de produtos. Assim, um dos grandes objetivos consiste em identificar novas estirpes com atividade antimicrobiana para utilização na produção de queijos mais seguros e de melhor qualidade. […].info:eu-repo/semantics/publishedVersio

Comparison of Bacterial Diversity in Azorean and Hawai'ian Lava Cave Microbial Mats

Copyright © 2014 Taylor & Francis Group, LLC.Worldwide, lava caves host colorful microbial mats. However, little is known about the diversity of these microorganisms, or what role they may play in the subsurface ecosystem. White and yellow microbial mats were collected from four lava caves each on the Azorean island of Terceira and the Big Island of Hawai’i, to compare the bacterial diversity found in lava caves from two widely separated archipelagos in two different oceans at different latitudes. Scanning electron microscopy of mat samples showed striking similarities between Terceira and Hawai’ian microbial morphologies. 16S rRNA gene clone libraries were constructed to determine the diversity within these lava caves. Fifteen bacterial phyla were found across the samples, with more Actinobacteria clones in Hawai’ian communities and greater numbers of Acidobacteria clones in Terceira communities. Bacterial diversity in the subsurface was correlated with a set of factors. Geographical location was the major contributor to differences in community composition (at the OTU level), together with differences in the amounts of organic carbon, nitrogen and copper available in the lava rock that forms the cave. These results reveal, for the first time, the similarity among the extensive bacterial diversity found in lava caves in two geographically separate locations and contribute to the current debate on the nature of microbial biogeography

Cave microbial community composition in oceanic islands: disentangling the effect of different colored mats in diversity patterns of Azorean lava caves

Processes determining diversity and composition of bacterial communities in island volcanic caves are still poorly understood. Here, we characterized colored microbial mats in 14 volcanic caves from two oceanic islands of the Azores using 16S rRNA gene sequences. Factors determining community diversity (α) and composition (β) were explored, namely colored mats, caves and islands, as well as environmental and chemical characteristics of caves. Additive partitioning of diversity using OTU occurrence showed a greater influence of β-diversity between islands and caves that may relate to differences in rare OTUs (singletons and doubletons) across scales. In contrast, Shannon diversity partitioning revealed the importance of the lowest hierarchical level (α diversity, colored mat), suggesting a dominance of cosmopolitan OTUs (\u3e1%) in most samples. Cosmopolitan OTUs included members involved in nitrogen cycling, supporting the importance of this process in Azorean caves. Environmental and chemical conditions in caves did not show any significant relationship to OTU diversity and composition. The absence of clear differences between mat colors and across scales may be explained by (1) the geological youth of the cave system (cave communities have not had enough time to diverge) or/and (2) community convergence, as the result of selection pressure in extreme environments