Oxidoreductases and metal cofactors in the functioning of the earth

: Life sustains itself using energy generated by thermodynamic disequilibria, commonly existing as redox disequilibria. Metals are significant players in controlling redox reactions, as they are essential components of the engine that life uses to tap into the thermodynamic disequilibria necessary for metabolism. The number of proteins that evolved to catalyze redox reactions is extraordinary, as is the diversification level of metal cofactors and catalytic domain structures involved. Notwithstanding the importance of the topic, the relationship between metals and the redox reactions they are involved in has been poorly explored. This work reviews the structure and function of different prokaryotic organometallic-protein complexes, highlighting their pivotal role in controlling biogeochemistry. We focus on a specific subset of metal-containing oxidoreductases (EC1 or EC7.1), which are directly involved in biogeochemical cycles, i.e., at least one substrate or product is a small inorganic molecule that is or can be exchanged with the environment. Based on these inclusion criteria, we select and report 59 metalloenzymes, describing the organometallic structure of their active sites, the redox reactions in which they are involved, and their biogeochemical roles

Análise por genómica comparativa do género Ensifer revela adaptações a ambientes cavernícolas

One of the most prominent features of the bacterial species belonging to the Ensifer genus is their predatory behavior against other bacteria. Over the years members of Ensifer have been isolated from a variety of different environments, some of them imposing extreme conditions for life. One of those extremes is the subsurface environment, more specifically, caves. The particularities of cave environments, such as the deprivation of sunlight and the geological isolation to the surrounding environments, makes caves extremely oligotrophic environments. However, even with high levels of oligotrophy, caves are not by any means barren. It has been shown that caves harbor diverse consortia of microorganisms that use a diverse set of metabolic strategies for survival and contribute to the cave formation in ways that were not initially thought of. To better understand the necessary adaptations for the microbial colonization of caves, a comprehensive bioinformatic approach was conducted using Ensifer as a model genus, and more specifically, by comparison of different Ensifer strains isolated from different environments. We were able to show that cave Ensifer strains diverge from their surface relatives, showing an environment-driven clustering pattern in all the phylogenetic approaches conducted. Furthermore, by combining ANI with multi-gene phylogeny it was clear that the cave strains represent two different putative cave genospecies, highlighting the potential of using these two types of approaches to access the relatedness between Ensifer strains. Regarding the functional genes, the presence of the nopaline transporters sheds light on a possible ancient horizontal gene transfer event, and the identification of structural proteins of different ABC transporters, suggests the ability to utilize different resources inside the cave. The RND efflux pumps also shown an environmental- driven clustering pattern, which could be related to the different compounds and antibiotics present in caves. Also, over-represented biosynthetic gene clusters coding for quorum sensing and energy storage molecule suggests that cave strains rely on cellular communication and on the ability to preserve energy for survival. A complete absence of the CRISPR arrays in the genus Ensifer indicates that these strains are not exposed to intense viral predation. The difference between the unique genes of cave Ensifer strains highlights the fact that different caves can have a unique genomic pool, and therefore different caves strains can have different unique genes, ultimately responsible for the adaptation of Ensifer to that specific cave environment. These findings are insightful to understand how microorganisms adapt to caves, and highlight how further studies are needed to deeply explore the genomic diversity of Ensifer strains inhabiting the cave environment.Uma das características mais proeminentes das espécies bacterianas pertencentes ao género Ensifer é o seu comportamento predatório contra outras bactérias. Ao longo dos anos, membros deste género foram isolados a partir de uma variedade de ambientes diferentes, alguns com condições extremas para a vida. Um desses extremos é o ambiente subterrâneo, mais especificamente grutas. As particularidades dos ambientes cavernícolas, como a ausência de luz solar e o isolamento geológico relativo aos ambientes circundantes, tornam as grutas ambientes extremamente oligotróficos. No entanto, mesmo com altos níveis de oligotrofia, as grutas não são, de modo algum, estéreis. Tem sido demonstrado que as grutas abrigam diversos microrganismos que usam um conjunto diversificado de estratégias metabólicas para a sobrevivência e contribuem para a formação de grutas de formas que, inicialmente, não lhes era atribuída. Para entender melhor as adaptações necessárias para a colonização microbiana de grutas, foi desenvolvida uma abordagem bioinformática abrangente, utilizando Ensifer como género-modelo e, mais especificamente, pela comparação de diferentes estirpes de Ensifer isoladas em diferentes ambientes. Foi demonstrado que estirpes Ensifer cavernícolas divergem dos seus relativos de superfície, mostrando um padrão de agrupamento similar em todas as análises filogenéticas conduzidas. Adicionalmente, ao combinar o ANI com filogenia usando múltiplos genes, demonstrou-se que as estirpes cavernícolas representam duas genoespécies putativas de grutas, destacando o potencial destes dois tipos de abordagens na avaliação da relação entre estirpes de Ensifer. Relativamente aos genes funcionais, a presença de transportadores de nopalina elucida sobre a ocorrência de um possível evento de transferência horizontal de genes no passado, e a identificação de diferentes proteínas estruturais de vários transportadores ABC sugere a capacidade das estirpes cavernícolas de utilizar diferentes recursos no interior da gruta. As bombas de efluxo RND mostram também um padrão de agrupamento de acordo com o ambiente, que pode estar relacionado com os diferentes compostos e antibióticos presentes nas grutas. O enriquecimento de clusters de genes bio sintéticos que codificam para quorum sensing e para moléculas de armazenamento de energia, sugere que estirpes cavernícolas dependem de comunicação celular e da capacidade de preservar energia para sobreviver. Uma ausência absoluta de elementos CRISPR no género Ensifer indica que estas estirpes não estão expostas a uma predação viral intensa. A diferença entre genes únicos de estirpes de Ensifer cavernícolas, enfatiza o facto de diferentes estirpes poderem ter um pool genómico único, responsável pela adaptação de Ensifer a ambiente cavernícolas específicos, isto é, diferentes grutas. Estes resultados são importantes para compreender as adaptações de microrganismos a grutas e realçam a necessidade de mais estudos para explorar a fundo a diversidade genómica de estirpes de Ensifer que habitam grutas.Mestrado em Microbiologi

The potentials of photocatalytic cement in urban furniture

Photocatalytic cement has the property of cleaning air pollution. This is achieved by introducing titanium dioxide into the paste. The use of this material in urban furniture can provide a significant reduction in the pollution index. This article presents some design proposals for urban furniture with this material in Portugal.O cimento fotocatalítico tem a propriedade de limpar a poluição do ar. Isto é conseguido introduzindo dióxido de titânio na pasta. O uso deste material no mobiliário urbano pode proporcionar uma redução signnificativa no índice de poluição. Este artigo apresenta algumas propostas projetuais de mobiliário urbano com esse material em Portugal

PROPOSTA DE USO DO CIMENTO FOTOCATALÍTICO EM MOBILIÁRIO URBANO – ESTUDO DE CASO EM PORTUGAL

O cimento fotocatalítico tem a propriedade de limpar a poluição do ar, através da introdução de dióxido de titânio na pasta original. O uso deste material no mobiliário urbano pode proporcionar uma redução significativa no índice de poluição. Este artigo apresenta algumas propostas projetuais de mobiliário urbano com esse material em Portugal. A pesquisa foi realizada durante o período de agosto de 2019 a janeiro de 2020, na região de Leiria.

PROPOSTA DE USO DO CIMENTO FOTOCATALÍTICO EM MOBILIÁRIO URBANO – ESTUDO DE CASO EM PORTUGAL

O cimento fotocatalítico tem a propriedade de limpar a poluição do ar, através da introdução de dióxido de titânio na pasta original. O uso deste material no mobiliário urbano pode proporcionar uma redução significativa no índice de poluição. Este artigo apresenta algumas propostas projetuais de mobiliário urbano com esse material em Portugal. A pesquisa foi realizada durante o período de agosto de 2019 a janeiro de 2020, na região de Leiria.

Mapping the microbial diversity associated with different geochemical regimes in the shallow-water hydrothermal vents of the Aeolian archipelago, Italy

: Shallow-water hydrothermal vents are unique marine environments ubiquitous along the coast of volcanically active regions of the planet. In contrast to their deep-sea counterparts, primary production at shallow-water vents relies on both photoautotrophy and chemoautotrophy. Such processes are supported by a range of geochemical regimes driven by different geological settings. The Aeolian archipelago, located in the southern Tyrrhenian sea, is characterized by intense hydrothermal activity and harbors some of the best sampled shallow-water vents of the Mediterranean Sea. Despite this, the correlation between microbial diversity, geochemical regimes and geological settings of the different volcanic islands of the archipelago is largely unknown. Here, we report the microbial diversity associated with six distinct shallow-water hydrothermal vents of the Aeolian Islands using a combination of 16S rRNA amplicon sequencing along with physicochemical and geochemical measurements. Samples were collected from biofilms, fluids and sediments from shallow vents on the islands of Lipari, Panarea, Salina, and Vulcano. Two new shallow vent locations are described here for the first time. Our results show the presence of diverse microbial communities consistent in their composition with the local geochemical regimes. The shallow water vents of the Aeolian Islands harbor highly diverse microbial community and should be included in future conservation efforts

Surface Bacterioplankton Community Structure Crossing the Antarctic Circumpolar Current Fronts

The Antarctic Circumpolar Current (ACC) is the major current in the Southern Ocean, isolating the warm stratified subtropical waters from the more homogeneous cold polar waters. The ACC flows from west to east around Antarctica and generates an overturning circulation by fostering deep-cold water upwelling and the formation of new water masses, thus affecting the Earth’s heat balance and the global distribution of carbon. The ACC is characterized by several water mass boundaries or fronts, known as the Subtropical Front (STF), Subantarctic Front (SAF), Polar Front (PF), and South Antarctic Circumpolar Current Front (SACCF), identified by typical physical and chemical properties. While the physical characteristics of these fronts have been characterized, there is still poor information regarding the microbial diversity of this area. Here we present the surface water bacterioplankton community structure based on 16S rRNA sequencing from 13 stations sampled in 2017 between New Zealand to the Ross Sea crossing the ACC Fronts. Our results show a distinct succession in the dominant bacterial phylotypes present in the different water masses and suggest a strong role of sea surface temperatures and the availability of Carbon and Nitrogen in controlling community composition. This work represents an important baseline for future studies on the response of Southern Ocean epipelagic microbial communities to climate change