RESUMO
Hyperthermophilic Archaea and Bacteria with optimal growth temperatures between 80 and 110°C have been isolated from geo- and hydro-thermally heated terrestrial and submarine environments. 16S rRNA sequence comparisons indicate great phylogenetic diversity among the 23 different genera represented. Hyperthermophiles consist of anaerobic and aerobic chemolithoautotrophs and heterotrophs growing at neutral or acidic pH. Their outstanding heat resistance makes them as interesting objects for basic research as for biotechnology in the future.
RESUMO
Hot springs and hydrothermal systems occurring within volcanic areas are inhabited by hyperthermophilic microorganisms, some of which grow at temperatures up to 110 degrees C. Hyperthermophiles grow anaerobically or aerobically by diverse metabolic types. Within the high temperature ecosystems, primary production is independent from solar energy.
Assuntos
Archaea/classificação , Bactérias/classificação , Temperatura Alta , Microbiologia do Solo , Microbiologia da Água , Archaea/fisiologia , Archaea/ultraestrutura , Bactérias/ultraestrutura , Fenômenos Fisiológicos Bacterianos , Ecossistema , Filogenia , Erupções VulcânicasRESUMO
Sulphur-dependent archaebacteria, which are found around nearly boiling continental solfataric springs and mud holes, can be assigned to two distinct branches: the aerobic, sulphur-oxidizing Sulfolobales and the strictly anaerobic sulphur-reducing Thermoproteales. Here, we report the isolation of a group of extremely thermophilic solfataric archaebacteria that are able to grow either strictly anaerobically by reduction, or fully aerobically by oxidation of molecular sulphur, depending on the oxygen supply. We have also established that the ability to grow in these two ways is shared by Sulfolobus brierleyi, a well-known less thermophilic sulphur-oxidizing archaebacterium capable of ore-leaching. The phenomenon may be dependent on a fundamental switch in genome expression. These organisms might represent the primitive fore-runners of sulphur-oxidizing archaebacteria, meeting their energy requirements either by oxidation or by reduction of the same element.
