Microbial diversity and biogeochemical cycling in soda lakes

Soda lakes contain high concentrations of sodium carbonates resulting in a stable elevated pH, which provide a unique habitat to a rich diversity of haloalkaliphilic bacteria and archaea. Both cultivation-dependent and -independent methods have aided the identification of key processes and genes in the microbially mediated carbon, nitrogen, and sulfur biogeochemical cycles in soda lakes. In order to survive in this extreme environment, haloalkaliphiles have developed various bioenergetic and structural adaptations to maintain pH homeostasis and intracellular osmotic pressure. The cultivation of a handful of strains has led to the isolation of a number of extremozymes, which allow the cell to perform enzymatic reactions at these extreme conditions. These enzymes potentially contribute to biotechnological applications. In addition, microbial species active in the sulfur cycle can be used for sulfur remediation purposes. Future research should combine both innovative culture methods and state-of-the-art ‘meta-omic’ techniques to gain a comprehensive understanding of the microbes that flourish in these extreme environments and the processes they mediate. Coupling the biogeochemical C, N, and S cycles and identifying where each process takes place on a spatial and temporal scale could unravel the interspecies relationships and thereby reveal more about the ecosystem dynamics of these enigmatic extreme environments

Cell wall glucan remodeling is required for Candida albicans adhesion and invasion

The fungal cell wall plays a crucial role in host-pathogen interactions. Its formation is the result of the coordinated activity of several extracellular enzymes which assemble the constituents, remodel and hydrolyze them in the extracellular space. Candida albicans Phr1 and Phr2 proteins belong to Family GH72 of \uf062(1,3)-glucanosyltransferases and play a crucial role in cell wall assembly. PHR1 and PHR2 are differently regulated by extracellular pH. PHR1 is expressed when ambient pH is 5.5 or higher whereas PHR2 has the reverse expression pattern. Their deletion causes a pH-conditional defect in morphogenesis and virulence. In this work we explored whether PHR1 deletion affects C. albicans potential to invade human epithelia. We exploited a reconstituted human epithelium (RHE) as a model system. After 24 h from the exposure of RHE to the control cells (CAI-10) or to a PHR1 null mutant (CAS-10) the effects on invasion were scored. Control cells penetrated the entire epithelium layer very efficiently and invaded the underlying collagen matrix whereas the incubation with the mutant cells did not result in penetration of the epithelium and consequently no invasion of the matrix was detectable. The lack of cells in proximity of the epithelium layer suggested that adhesion might also be affected. Thus we studied the behavior of delta-phr1 cells in different adhesion assays. The mutant cells exhibited a marked reduction in the adhesion to abiotic surfaces. About 80% of the control cells were adhered within 30 min from transfer to adhesion conditions increasing to about 95% by 2h. The extent of adherence of PHR1 null mutant cells was greatly reduced since only 20% adhered by 30 min increasing to a maximum of about 30% by 2h. Next we tested the ability of PHR1 null mutant to adhere to monolayers of human epithelial cells. A similar defect in adhesion was detected. Transcription profiling of selected hyphal-specific and adhesin-encoding genes during adhesion indicates that in the PHR1 null mutant HWP1 and ECE1 transcript levels are markedly reduced. Our results suggest that expression of PHR1 strongly contributes to adhesion and invasion, two processes that promote the establishment of C. albicans infections and progression

Adaptation, adhesion and invasion during interaction of Candida albicans with the host. Focus on the function of cell wall proteins

Infectious diseases have long been regarded as losing their threat to mankind. However, in the recent decades infectious diseases have been regaining grounds and are back in the focus of research. This is also due to the fact that medical progress has enabled us to treat and cure a much higher fraction of severe diseases or trauma, resulting in a significant proportion of temporarily or constantly immune-suppressed patients. Infectious diseases result from the interplay between pathogenic microorganisms and the hosts they infect, especially their defense systems. Consequently, immune-suppressed patients are at high risk to succumb from opportunistic infections, like Candida infections. To study the balance between host and C. albicans with regard to the establishment of disease or asymptomatic, commensal colonisation, we developed host-pathogen interaction systems to study both the adaptation of C. albicans to different epithelia as well as to investigate the sensors of the innate immune system, the pattern recognition receptors. These host-pathogen interaction systems, as well as some of the results gained are described in this review

Integrated energy efficient data centre management for green cloud computing: the FP7 GENiC project experience

Energy consumed by computation and cooling represents the greatest percentage of the average energy consumed in a data centre. As these two aspects are not always coordinated, energy consumption is not optimised. Data centres lack an integrated system that jointly optimises and controls all the operations in order to reduce energy consumption and increase the usage of renewable sources. GENiC is addressing this through a novel scalable, integrate energy management and control platform for data centre wide optimisation. We have implemented and prototype of the platform together with workload and thermal management algorithms. We evaluate the algorithms in a simulation based model of a real data centre. Results show significant energy savings potential, in some cases up to 40%, by integrating workload and thermal management

The GENiC architecture for integrated data centre energy management

We present an architecture for integrated data centre energy management developed in the EC funded GENiC project. The architecture was devised to create a platform that can integrate functions for workload management, cooling, power management and control of heat recovery for future, highly efficient data centres. The architecture is based on a distributed systems approach that allows the integration of components developed by several entities through defined interfaces and data formats. We also present use cases for the architecture, a brief description of the project's prototypical implementation, evaluation metrics and some lessons learned

ICT - Energy Concepts for Energy Efficiency and Sustainability

Data centres are part of today's critical information and communication infrastructure, and the majority of business transactions as well as much of our digital life now depend on them. At the same time, data centres are large primary energy consumers, with energy consumed by IT and server room air conditioning equipment and also by general building facilities. In many data centres, IT equipment energy and cooling energy requirements are not always coordinated, so energy consumption is not optimised. Most data centres lack an integrated energy management system that jointly optimises and controls all its energy consuming equipments in order to reduce energy consumption and increase the usage of local renewable energy sources. In this chapter, the authors discuss the challenges of coordinated energy management in data centres and present a novel scalable, integrated energy management system architecture for data centre wide optimisation. A prototype of the system has been implemented, including joint workload and thermal management algorithms. The control algorithms are evaluated in an accurate simulation‐based model of a real data centre. Results show significant energy savings potential, in some cases up to 40%, by integrating workload and thermal management