Bioinformatics challenges and potentialities in studying extreme environments

Cold environments are populated by organisms able to contravene deleterious effects of low temperature by diverse adaptive strategies, including the production of ice binding proteins (IBPs) that inhibit the growth of ice crystals inside and outside cells. We describe the properties of such a protein (EfcIBP) identified in the metagenome of an Antarctic biological consortium composed of the ciliate Euplotes focardii and psychrophilic non-cultured bacteria. Recombinant EfcIBP can resist freezing without any conformational damage and is moderately heat stable, with a midpoint temperature of 66.4 degrees C. Tested for its effects on ice, EfcIBP shows an unusual combination of properties not reported in other bacterial IBPs. First, it is one of the best-performing IBPs described to date in the inhibition of ice recrystallization, with effective concentrations in the nanomolar range. Moreover, EfcIBP has thermal hysteresis activity (0.53 degrees C at 50 mu M) and it can stop a crystal from growing when held at a constant temperature within the thermal hysteresis gap. EfcIBP protects purified proteins and bacterial cells from freezing damage when exposed to challenging temperatures. EfcIBP also possesses a potential N-terminal signal sequence for protein transport and a DUF3494 domain that is common to secreted IBPs. These features lead us to hypothesize that the protein is either anchored at the outer cell surface or concentrated around cells to provide survival advantage to the whole cell consortium

Status of Geothermal Research and Development in the World Situation mondiale de la Recherche et du Développement géothermiques

The heat flow observed on the earth's surface (on averageof 59 mW/m2) mainly derives from the heat generated by the decay of radioactive elements (U238, U235, Th232, K40) in the crust. The distribution of heat flow values is closely tied to the phenomena described in theplate tectonicstheory: most of the surface geothermal anomalies and, consequently, the industrially exploitable geothermal areas, are located in correspondence to spreading ridges (geothermal fields of lceland, Kenya, Ethiopia, etc. ) and subduction zones (Indonesia Japon, Indian and Chinese Himalayas, Chile, etc. ). However, geothermal fields can also be found in intraplate zones in areas with a normal heat flow value (e. g. , Paris basin) or slightly higher (e. g. Hungarian basin). Generally these fields produce a low-enthalpy fluid that can be used for non-electric exploitation. The best-known geothermal systems, and the only ones exploited so far, belong to the 'hydrothermal convective' type. These occur wherever a fluid circulation, mainly of meteoric origin, is able to develop in sufficiently permeable rocks near a heat source (such as a magmatic intrusion) or at depths at which it can be heated by the normal geothermal gradian. This type of system is usually divided intowater-dominatedsystems, where the continuous fluid phase in the reservoir is liquid andvapour dominatedsystems where steam is the continuous phase. Other geothermal systems have still to be utilized and probably will be exploited as progress is made in technology. These are: a) geopressured systems, found in some subsident sedimentary basins containing high-temperature connate waters of near lithostatic pressure; b) the so-called 'hot dry rocks', which can be used ta create artificial systems by artificial fracturing of the high-temperature rocks and induced circulation of closed-circuit fluids. Geothermal energy is exploited: a) To generate electricity. The total installed geothermoelectric capacity throughout the world (1979) is 2,063 MWe. Nowadays the most advanced countries where geothermal energy is concerned are the USA (908 MWe), Italy (421 MWe), New Zealand (202 MWe) and Japon (171 MWe). Research is under way in various countries, directed at begining production or increasing present levels. By 1985 the installed geothermoelectric capacity should be around 6,500 MWe. b) For non-electric uses. There are various applications of geothermal energy, the main ones being in space-heating and agriculture (especially greenhouses). Iceland and Hungary have developed these uses on a particularly large scale, but the situation in the USA, France and several other countries is also interesting. It is difficult to evaluate the capacity involved in this type of exploitation but the 1977 estimate was given as 6,200 MWt. Le flux de chaleur observé à la surface de la terre (59 mW/m2 en moyenne) provient en majeure partie de la désintégration d'éléments radioactifs (U238, 0235, Th232, K40) dans la croûte. La répartition des intensités de flux de chaleur est liée intimement aux phénomènes décrits par la théorie dite tectonique des plaques : la plupart des anomalies géothermiques de surface, et en conséquence la plupart des régions exploitables industriellement pour la géothermie, se situent à proximité des rides d'expansion (champs géothermiques d'Islande, du Kenya, d'Éthiopie) ou des zones de subduction (Indonésie, Japon, Himalaya chinois ou indien, Chili, etc. ). On peut aussi trouver des champs géothermiques dans des bassins au sein des continents avec des flux de chaleur normaux (par exemple bassin de Paris) ou un peu plus élevés (par exemple dépression hongroise). En général ces champs produisent des fluides de moyenne température destinés à des usages non électriques. Le système géothermique le mieux connu, et le seul exploité jusqu'à maintenant, appartient au type dit deconvection géothermique . II se produit lorsqu'une circulation d'eaux, principalement météoriques, peut se développer dans des roches assez perméables à proximité d'une source de chaleur (telle qu'une intrusion magmatique) ou a des profondeurs suffisantes pour qu'elle soit échauffée par le quotient géothermique normal. On subdivise habituellement ces types de systèmes entre ceux où le fluide qui circule dans le réservoir est en phase liquide et ceux où ce fluide est en phase vapeur. On doit encore essayer d'autres systèmes géothermiques qui seront probablement exploités lorsque les progrès technologiques suffisants auront été réalisés. Ce sont : a) les systèmes à pression géostatiques, rencontrés dans des bassins sédimentaires subsidents contenant des eaux connées à haute température et à pression voisine de la pression litho-statique ; b) les systèmes dits deroches-sèchesoù l'on peut créer un mécanisme artificiel par fracturation de roches à hautes températures et par circulation fermée des fluides. L'énergie géothermique est exploitée : 1) Pour produire de l'électricité - la capacité géothermique électrique installée en 1979 est de 2063 MWe. A l'heure actuelle les contrées les plus avancées dans ce domaine sont les États Unis (908 MWe), l'Italie (421 MWe), la Nouvelle-Zélande (202 MWe) et le Japon (171 MWe). Des recherches sont en cours dans différents pays pour commencer ou accroître faproduction. Vers 1985 la capaciéé installée devrait être de l'ordre de 6500 MWe. 2) Pour les usages non électriques, il y a diverses applications de l'énergie géothermique, en particulier pour le chauffage de locaux et pour l'agriculture (serres). L'Islande et la Hongrie ont développé ces utilisations sur une vaste échelle, mais on doit signaler aussi des efforts aux États-Unis, en France et dans d'autres pays. II est difficile d'évaluer le bilan total de ces types d'exploitation mais en 1977 on l'estimait autour de 6200 MWt

Status of Geothermal Research and Development in the World

The heat flow observed on the earth's surface (on averageof 59 mW/m2) mainly derives from the heat generated by the decay of radioactive elements (U238, U235, Th232, K40) in the crust. The distribution of heat flow values is closely tied to the phenomena described in theplate tectonicstheory: most of the surface geothermal anomalies and, consequently, the industrially exploitable geothermal areas, are located in correspondence to spreading ridges (geothermal fields of lceland, Kenya, Ethiopia, etc. ) and subduction zones (Indonesia Japon, Indian and Chinese Himalayas, Chile, etc. ). However, geothermal fields can also be found in intraplate zones in areas with a normal heat flow value (e. g. , Paris basin) or slightly higher (e. g. Hungarian basin). Generally these fields produce a low-enthalpy fluid that can be used for non-electric exploitation. The best-known geothermal systems, and the only ones exploited so far, belong to the 'hydrothermal convective' type. These occur wherever a fluid circulation, mainly of meteoric origin, is able to develop in sufficiently permeable rocks near a heat source (such as a magmatic intrusion) or at depths at which it can be heated by the normal geothermal gradian. This type of system is usually divided intowater-dominatedsystems, where the continuous fluid phase in the reservoir is liquid andvapour dominatedsystems where steam is the continuous phase. Other geothermal systems have still to be utilized and probably will be exploited as progress is made in technology. These are: a) geopressured systems, found in some subsident sedimentary basins containing high-temperature connate waters of near lithostatic pressure; b) the so-called 'hot dry rocks', which can be used ta create artificial systems by artificial fracturing of the high-temperature rocks and induced circulation of closed-circuit fluids. Geothermal energy is exploited: a) To generate electricity. The total installed geothermoelectric capacity throughout the world (1979) is 2,063 MWe. Nowadays the most advanced countries where geothermal energy is concerned are the USA (908 MWe), Italy (421 MWe), New Zealand (202 MWe) and Japon (171 MWe). Research is under way in various countries, directed at begining production or increasing present levels. By 1985 the installed geothermoelectric capacity should be around 6,500 MWe. b) For non-electric uses. There are various applications of geothermal energy, the main ones being in space-heating and agriculture (especially greenhouses). Iceland and Hungary have developed these uses on a particularly large scale, but the situation in the USA, France and several other countries is also interesting. It is difficult to evaluate the capacity involved in this type of exploitation but the 1977 estimate was given as 6,200 MWt

A Systems Biology and Ecology Framework for POPs Bioaccumulation in Marine Ecosystems

We propose a modelling framework for studying bioaccumulation of Persistent Organic Pollutants (POPs) and microbial bioremediation in the Adriatic food web. The integration of network estimation methods, ODE simulation and sensitivity analysis and tools from synthetic biology allows investigating multiscale effects and biological responses to POPs contamination, from the molecular level (bacteria metabolism) to the ecosystem level (food web) of a marine ecosystem

Topiramate in the treatment of chronic migraine

The purpose of this study was to evaluate the efficacy of topiramate in the treatment of chronic migraine. This was a double-blind, randomized, placebo controlled, parallel-group study. Patients suffering from chronic migraine with analgesic overuse were randomly assigned in a 1 : 1 ratio to receive topiramate or placebo. Following a baseline phase of eight weeks, the study drug was titrated in 25-mg increments over one week to 50 mg daily. Titration phase was followed by a 8-week maintenance phase. Number of days with headache during a 28-day period was the efficacy variable. At baseline, there was no difference in the number of days with headache between patients treated with topiramate and those treated with placebo (mean +/- SD: 20.9 +/- 3.2 and 20.8 +/- 3.2, respectively). During the last 4 week-maintenance phase, topiramate-treated patients experienced a significantly lower 28-day headache frequency in comparison to those treated with placebo (mean number of days with headache +/- SD: 8.1 +/- 8.1 vs. 20.6 +/- 3.4, P < 0.0007). Topiramate at low doses proved to be an effective therapeutic approach to reduce headache frequency in patients with chronic migraine and analgesic overuse

Computational Bioaccumulation Modelling of Pops in the Adriatic Ecosystem: a Network Analysis Approach

When a Persistent Organic Polluttant (POP) is released into the environment, intentionally or not, its fate and its ecological impact for both living organisms and environment can be hardly predicted. Polluttants enter protein pathways at the cell surface or inside organisms. Current trends in Systems Biology aim to study how living organisms adapt to environmental stressors (e.g. exposure to pollutants) considering classical food webs and molecular pathways as a whole [1]. We propose a computational framework to study long-term bioaccumulation dynamics in the marine ecosystem, and to identify keystone species in polluted food webs. Starting from a literature data and using the Linear Inverse Modeling (LIM) method [2], we have reconstructed the network structure, estimating trophic and contaminant flows. Then, the flow rates of the static contaminant network are used in the parametrization of a ODE-based dynamic bioaccumulation model. Keystone species identification is accomplished with network analysis tools (trophic and topological centrality indices), and with a newly introduced network index, Sensitivity Centrality (SC) [3], based on the sensitivity analysis technique. Results show that keystones, as identified by SC, have a prominent impact on global indices of the contaminated network, thus providing an effective way to detect sentinel species in a polluted environment