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推荐:瑞士学者Hauke Hennecke的研究方向

已有 6174 次阅读 2010-6-4 03:34 |个人分类:根瘤菌研究课题组介绍|系统分类:科研笔记| Hauke, Hennecke

Hauke Hennecke, Institute of Microbiology, ETH, Zurich, Switzerland

Curriculum vitae

Hauke Hennecke has been Professor of Microbiology at the Institute of Microbiology at the ETH Zurich since April 1983. He is Chairman of the Department of Biology at the ETH Zurich since 1 March 2005.

Hennecke, born on October 30, 1947, from Trier, Germany, studied biology and chemistry at the University of Munich and obtained his PhD degree at the University of Regensburg under the supervision of Professor A. Böck. After a two-year postdoctoral position at the University of California in Davis, he returned to Munich and completed his habilitation in 1981 in the area of microbiology. In 1982, Hennecke obtained a C2-professorship of microbiology. On April 1st, 1983 he was called to the ETH Zurich, at first as Associate Professor, and was then promoted to Full Professor on October 1, 1985.

Main points of his research are the study of symbiotic interaction between bacteria and plants, biological nitrogen fixation, the biogenesis of complex membrane-bound enzymes and molecular mechanisms of bacterial gene regulation. Hennecke is an elected member of several international scientific societies (e.g. the Leopoldina), and has received research prizes and calls from universities outside Switzerland. Between 1998 and 2002 he was president of the ETH research committee.

The soil bacterium Bradyrhizobium japonicum has two principle life styles: free-living in soil or laboratory culture, and endosymbiotic within infected cells of soybean root nodules, where the bacterium performs nitrogenase-catalyzed fixation of molecular nitrogen for the benefit of the host. Concurrent with the conversion from free-living to symbiotic, the bacterium changes from an oxic to an extremely micro-oxic environment. Life in micro-oxia is possible because B. japonicum respires with the help of a high-affinity cytochrome oxidase that consumes the oxygen released slowly from oxy-leghemoglobin, an oxygen-binding protein of the host plant. The cytoplasm of the symbiotic bacterium is thus kept anoxic. This is an optimal niche for the function of the oxygen-sensitive nitrogenase. Research activity in the Hennecke group deals with many aspects of the physiology of the endosymbiont. Particular emphasis lies on processes in which the ambient oxygen concentration and the redox balance play critical roles in the regulation of gene expression and diverse symbiotic functions. The available genome sequence and tools for transcriptomics and proteomics facilitate systems biology approaches to understand complex intracellular networks in free-living and symbiotic B. japonicum.

Research projects
  • Project 1: Regulatory networks »»
  • Project 2: Molecular biology of root nodule bacteroids  »»
  • Project 3: Analysis of symbiotically defective mutants  »»
  • Project 4: Biogenesis of cytochrome oxidases  »»
  • Special techniques and tools: B. japonicum gene chip  »»

N2 Fixation

N2 Fixation

Left: Root nodules resulting from the symbiotic interaction of Bradyrhizobium japonicum with its soybean host plant. Center: Section through a root nodule. The red color originates from the plant-derived protein leghemoglobin which reversibly binds oxygen. Right: Nitrogen-fixing B. japonicum bacteroids in an infected soybean root nodule cell.

以上内容全部来自于原始网站:http://www.micro.biol.ethz.ch/research/hennecke

课题组的最新研究进展是:根瘤菌对宿主植物的适应

Mol Plant Microbe Interact. 2010 Jun;23(6):784-90.

Rhizobial adaptation to hosts, a new facet in the legume root-nodule symbiosis.

Koch M, Delmotte N, Rehrauer H, Vorholt JA, Pessi G, Hennecke H.

Institute of Microbiology, ETH, Zurich, Switzerland.

Abstract

Rhizobia are able to infect legume roots, elicit root nodules, and live therein as endosymbiotic, nitrogen-fixing bacteroids. Host recognition and specificity are the results of early programming events in bacteria and plants, in which important signal molecules play key roles. Here, we introduce a new aspect of this symbiosis: the adaptive response to hosts. This refers to late events in bacteroids in which specific genes are transcribed and translated that help the endosymbionts to meet the disparate environmental requirements imposed by the hosts in which they live. The host-adaptation concept was elaborated with Bradyrhizobium japonicum and three different legumes (soybean, cowpea, and siratro). Transcriptomes and proteomes in root-nodule bacteroids were analyzed and compared, and genes and proteins were identified which are specifically induced in only one of the three hosts. We focused on those determinants that were congruent in the two data sets of host-specific transcripts and proteins: seven for soybean, five for siratro, and two for cowpea. One gene cluster for a predicted ABC-type transporter, differentially expressed in siratro, was deleted in B. japonicum. The respective mutant had a symbiotic defect on siratro rather than on soybean or cowpea. This result demonstrates the value of the applied approach and corroborates the host-specific adaptation concept.

PMID: 20459317 [PubMed - in process]



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