Use of 16S rRNA Gene Based Clone Libraries to Assess Microbial Communities Potentially Involved in Anaerobic Methane Oxidation in a Mediterranean Cold Seep

This study provides data on the diversities of bacterial and archaeal communities in an active methane seep at the Kazan mud volcano in the deep Eastern Mediterranean sea. Layers of varying depths in the Kazan sediments were investigated in terms of (1) chemical parameters and (2) DNA-based microbial population structures. The latter was accomplished by analyzing the sequences of directly amplified 16S rRNA genes, resulting in the phylogenetic analysis of the prokaryotic communities. Sequences of organisms potentially associated with processes such as anaerobic methane oxidation and sulfate reduction were thus identified. Overall, the sediment layers revealed the presence of sequences of quite diverse bacterial and archaeal communities, which varied considerably with depth. Dominant types revealed in these communities are known as key organisms involved in the following processes: (1) anaerobic methane oxidation and sulfate reduction, (2) sulfide oxidation, and (3) a range of (aerobic) heterotrophic processes. In the communities in the lowest sediment layer sampled (22–34 cm), sulfate-reducing bacteria and archaea of the ANME-2 cluster (likely involved in anaerobic methane oxidation) were prevalent, whereas heterotrophic organisms abounded in the top sediment layer (0–6 cm). Communities in the middle layer (6–22 cm) contained organisms that could be linked to either of the aforementioned processes. We discuss how these phylogeny (sequence)-based findings can support the ongoing molecular work aimed at unraveling both the functioning and the functional diversities of the communities under study

Energy landscapes shape microbial communities in hydrothermal systems on the Arctic Mid-Ocean Ridge

Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in hydrothermal systems through an investigation of two geochemically different basalt-hosted hydrothermal systems on the Arctic Mid-Ocean Ridge: the Soria Moria Vent field (SMVF) and the Loki’s Castle Vent Field (LCVF). Chemical energy landscapes were evaluated through modelling of the Gibbs energy from selected redox reactions under different mixing ratios between seawater and hydrothermal fluids. Our models indicate that the sediment-influenced LCVF has a much higher potential for both anaerobic and aerobic methane oxidation, as well as aerobic ammonium and hydrogen oxidation, than the SMVF. The modelled energy landscapes were used to develop microbial community composition models, which were compared with community compositions in environmental samples inside or on the exterior of hydrothermal chimneys, as assessed by pyrosequencing of partial 16S rRNA genes. We show that modelled microbial communities based solely on thermodynamic considerations can have a high predictive power and provide a framework for analyses of the link between energy availability and microbial community composition

Strongly Coupled Organic Microcavities

The photophysics of planar microcavities which employ organic materials as the optically resonant medium to achieve the strong-coupling regime is discussed. While as a result of the light\u2013matter coupling, cavity polariton branches appear which are analogous to those observed in inorganic microcavities, many properties of organic-based microcavities are qualitatively and quantitatively different. The electronic excitations involved are molecular Frenkel excitons, rather than large radius Wannier excitons, which lead to large Rabi splitting values. The effects of disorder are typically much more pronounced as well as the exciton-phonon coupling, possibly leading to vibronic replicas. As a consequence, polariton relaxation and polariton-polariton scattering mechanisms also show features specific to the organic material employed. The field of organic-based microcavities is attracting an increasing interest as high excitation density phenomena such as polariton lasing have recently been reported. In view of their experimental relevance, two different kinds of organic microcavities, disordered J-aggregate-based microcavities and crystalline anthracene microcavities, are considered

What start-up firms are more likely to obtain public funding support? A systematic analysis of the funding program promoted by the Abruzzo Region in Italy

The chapter aims to investigate the profile of start-up firms, in terms of features of the entrepreneur and entrepreneurial project, with regard to their likelihoods of obtaining support through public funding. Using data of 214 start-ups applied to the public call for the funding program implemented with the 2013-2016 "Start-Up Start-Hope” program promoted by the Abruzzo Region in Italy and funded by the European Social Fund, the main result from the estimated logistic model is that, generally, the key factor determining the probability of receiving public funding support is the entrepreneurs’ age. Specifically, older entrepreneurs and entrepreneurial teams have a lower probability to be awarded by the public program compared to younger ones. Nevertheless, the other project and firm selected variables for the analysis (firm size, project value and type of financing based on the stage development of the firm) are not significant factors determining the probability of receiving public funding support