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Über dieses Buch

Magnetotactic bacteria (MTB) synthesize intracellular nano-sized minerals of magnetite and/or greigite magnetosomes for magnetic orientation. They play important roles in global iron cycling and sedimentary magnetism, and have a broad range of potential applications in both biotechnological and biomedical fields. However, because the majority of MTB in nature remain unculturable, our understanding of these specific bacteria remains fairly limited. This thesis describes the development of a novel approach for effectively collecting, purifying and characterizing uncultivated magnetotactic bacteria. The diversity, genomic information and rock magnetic properties of various uncultivated MTB are investigated and characterized using a combination of biological and geophysical methods. The results will lead to a better understanding of the biogeography and biomineralization mechanisms of MTB in nature, and improve our knowledge of the contributions of MTB to biogeochemical cycles of elements and sedimentary magnetism.

Dr. Wei Lin works at the Institute of Geology and Geophysics, Chinese Academy of Sciences, China

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract
Iron is the fourth most common element in the Earth’s crust. It is a crucial nutrient for almost all organisms and plays an important role in the oceanic primary production process (Martin and Fitzwater 1988).
Wei Lin

Chapter 2. Enrichment, Purification and Characterization of Environmental Magnetotactic Bacteria

Abstract
Although magnetotactic bacteria (MTB) are ubiquitous in various aquatic or sedimentary environments, the majority of them are still unculturable. One of the most intriguing properties of MTB, in contrast to other bacteria, is their ability to swim along the magnetic field lines, which provides an opportunity to enrich and purify uncultivated MTB cells directly from environmental samples.
Wei Lin

Chapter 3. Diversity of Magnetotactic Bacteria and Its Environmental Implications

Abstract
Magnetotactic bacteria (MTB) are ubiquitous in aquatic and sedimentary environments, where they sometimes can be detected in high abundance (Spring et al. 2000; Amann et al. 2007; Edwards and Bazylinski 2008).
Wei Lin

Chapter 4. Metagenomic Analysis of Uncultivated Magnetotactic Bacteria Within the Phylum Nitrospirae

Abstract
MTB within the phylum Nitrospirae were first identified through a 16S rRNA gene-based survey in Lake Chiemsee near Munich, Germany.
Wei Lin

Chapter 5. Magnetic Properties of Uncultivated Magnetotactic Bacteria

Abstract
Magnetite is a stable carrier of natural remanent magnetization in sedimentary rocks and sediments. Studies of magnetite preserved in sediments provide novel knowledge in paleomagnetic directions and paleointensity of the geomagnetic field. However, our understanding of magnetic properties of ultrafine-grained magnetite particles is still very poor.
Wei Lin

Chapter 6. Concluding Remarks

Abstract
This thesis focuses on improving our knowledge on the diversity, distribution, genomic information, and magnetic properties of magnetotactic bacteria (MTB), which are a diverse group of microorganisms synthesized intracellular magnetic minerals of magnetite (Fe3O4) and/or greigite (Fe3S4) magnetosomes. MTB not only play significant roles in global iron cycling and bulk magnetic signals of sediments, but also are a perfect model system to study fundamental and general biomineralization mechanisms.
Wei Lin

Backmatter

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