title: The temperature gradient-forming device, an accessory unit for normal light microscopes to study the biology of hyperthermophilic microorganisms.
abstract: To date, the behavior of hyperthermophilic microorganisms in their biotope has been studied only to a limited degree; this is especially true for motility. One reason for this lack of knowledge is the requirement for high-temperature microscopy-combined, in most cases, with the need for observations under strictly anaerobic conditions-for such studies. We have developed a custom-made, low-budget device that, for the first time, allows analyses in temperature gradients up to 40°C over a distance of just 2 cm (a biotope-relevant distance) with heating rates up to ∼5°C/s. Our temperature gradient-forming device can convert any upright light microscope into one that works at temperatures as high as 110°C. Data obtained by use of this apparatus show how very well hyperthermophiles are adapted to their biotope: they can react within seconds to elevated temperatures by starting motility-even after 9 months of storage in the cold. Using the temperature gradient-forming device, we determined the temperature ranges for swimming, and the swimming speeds, of 15 selected species of the genus Thermococcus within a few months, related these findings to the presence of cell surface appendages, and obtained the first evidence for thermotaxis in Archaea.
authors.affiliation: Institute of Microbiology and Archaea-Centre, University of Regensburg, Regensburg, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Mora
authors.affiliation: Institute of Microbiology and Archaea-Centre, University of Regensburg, Regensburg, Germany.
authors.forename: Annett
authors.initials: A
authors.lastname: Bellack
authors.affiliation: Institute of Microbiology and Archaea-Centre, University of Regensburg, Regensburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Ugele
authors.affiliation: Electronic Workshop at the Faculty of Biology, University of Regensburg, Regensburg, Germany.
authors.forename: Johann
authors.initials: J
authors.lastname: Hopf
authors.affiliation: Institute of Microbiology and Archaea-Centre, University of Regensburg, Regensburg, Germany reinhard.wirth@ur.de.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Wirth
mesh_terms: D004867:Equipment Design; D006358:Hot Temperature; D008853:Microscopy / Q000295:instrumentation / Q000379:methods*; D019712:Thermococcus / Q000737:chemistry / Q000145:classification / Q000166:cytology*