Lehrstuhl für Mikrobiologie

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Overview about the different working groups on the institute of microbiology

So far, three domains of life are known: the Eucarya, the Bacteria and the Archaea. Almost all of the cultivated Archaea have been isolated from extreme environments, often characterized by volcanic activity. However, through the use of the 16S subunit RNA as a molecular marker, uncultivated Archaea have recently been discovered frequently in moderate temperature environments e.g. oceans, lakes or soils. We are working on the identification, isolation and characterisation of novel Archaea and Bacteria, including ultrastructure and molecular biology, especially transcription studies. To obtain microbial cell material, the isolates are grown at large scale in our fermentation plant.

Research in our laboratory showed that the archaeal transcription complex is very similar to the structure of the RNA polymerase II complex found in Eukarya. The interactions between the different subunits of the archaeal complex are studied in a project, together with the interactions of the transcription complex with promoter DNA.

A second project studies the transcriptional regulation of Pyrococcus.
This organism, which grows optimally at 100°C, can induce or repress the transcription of genes in response to the presence of a carbohydrate in the media, for instance genes necessary for degradation of cellobiose. Using an in our laboratory developed cell-free transcription system, archaeal gene-regulators and their regulatory mechanisms will be identified and studied.

The development and application of novel molecular identification methods allows the microbial analysis of high temperature ecosystems. For the fast and reliable isolation und subsequent growth of single cells from mixed cultures, a plating independent isolation method, based on the use of a laser microscope (“optical tweezers”), was developed.

In a further project, investigations on the recently discovered novel archaeal phylum of the “Nanoarchaeota” are carried out. The only cultivated representative of this phylum so far, Nanoarchaeum equitans, exhibits a cell diameter of only 400 nm and is therefore the smallest living cell known (about 100 times smaller than an E. coli cell). We study the physiology, biochemistry and genetics of this obligate hyperthermophilic symbiont / parasite in association with its host Ignicoccus.

In der Arbeitsgruppe "Elektronenmikroskopie" wird der Aufbau der Zellen und Zellhüllen von Ignicoccus und Nanoarchaeum untersucht. Diese beiden hyperthermophilen Archaeen werden zusammen in einer Kultur gezüchtet und bilden dabei einen unmittelbaren Kontakt zwischen den Zellen aus. Ziel der Untersuchungen ist das Verständnis der strukturellen und molekularen Details dieser Zell-Zell-Interaktion.

Flagellate

copyright: Prof. Dr. Gerhard Wanner, LMU

Prof. Wirth's group asks for the structure and function of various cell appendages of Archaea. Archaeal cell appendages, e.g. flagella, differ in their structure and mode of synthesis from those of Bacteria. In a systematic approach, we study different cell appendages of selected species of Archaea like flagella of Pyrococcus furiosus and Methanocaldococcus villosus, fimbriae of Methanothermobacter thermoautotrophicus, and fibers of Ignicoccus hospitalis. These analyses combine organismic approaches (like high-temperature light microscopy) with molecular (like cloning and expression of various proteins) and ultrastructural ones (like various electron microscopic techniques). A recently started project analyzes archaeal chemoreceptors and chemotaxis.

At the Biotechnikum of the Archaeenzentrum we use 11 different bioreactors (fermenters) in varios sizes, ranging from 7 to 300 lithres working capacity for the mass cultivation of microorganisms. These fermenters are especially constructed for the cultivation of Archaea and other high temperature microbes. Their natural terrestrial or marine volcanic can be simulated to produce large amounts of cell masses.

Fermentation - Archaeenzentrum Regensburg

copyright for all images: Universität Regensburg, Lehrstuhl Mikrobiologie

Overview about the different working groups on the institute of microbiology

Lehrstuhl für Mikrobiologie & Archaeenzentrum