Iron manganese biomineralization; Iron minerals in surface environments; Manganese minerals in surface environments; Crystal structures of manganese oxide minerals; Microbial biomineralization of iron and manganese; Microbial oxidation of organic matter coupled to the reduction of fe (III) and Mn(IV) oxides; Microbial accumulation of iron and manganese in different aquatic environments: an electron optical study; Magnetotactic bacteria: biomineralization, ecology, sediment magnetism, environmental indicator; Production of iron sulfide minerals by magnetotactic bacteria in sulfidic environments; Manganese oxides producec by fungal oxidation of manganese from siderite and rhodochrosite; Biogenic ferrihydrite: effect of B-thalassemia/ hemoglobin E disease onthe structure of ferrihydrite present in ferritins isolated from iron-loaded human heart and spleen tissue; Manganese nodules and microbial oxidation of manganese in the huntley meadows wetland, Virginia, USA; Iron sulfidization in tidal marsh soils; Mineralogy of precipitates formed by the biogeochemical oxidation of Fe(II) in mine drainage; Natural iron precipitates in a mine retention pond near Jabiru, Northern Territory, Australia; Iron deposits and microorganisms in saline sulfidic soils with altered soil water regimes in South Australia; Transformations of iron, manganese and aluminium during oxidation of a sulfidic material from an acid sulfate soil; Deposition and accumulation of biogenic magnetite in low oxygen facies ...

Iron is a common cation in biomineral sand; it is present for example in magnetite produced by magnetotactic bacteria and in iron sulfides produced by sulfate reducing microorganisms. The work presented in this thesis focused on two types of microorganisms capable of forming iron biominerals. In the first project I have studied the effect of O2 on the respiratory physiology and the formation of magnetosomes by Magnetospirillum magneticum AMB-1. In the second project I have studied the relationship between olivine and the activity of dissimilatory sulfate reducing (DSR) microorganisms. For the first project, I grew cells of AMB-1 in cultures with various concentrations of O2 and monitored growth and the formation of magnetic mineral particles (MMP). Results have shown that AMB-1 cells grew better at 100-225 uMO2(aq) than at lower [O2], yet the formation of MMP was repressed at ~45 u[mu]M O2(aq) and strongly inhibited at >100 u[mu]M O2(aq).These results have helped better understand the dissimilarity between the optimal growth conditions of magnetotactic bacteria and the conditions needed for the formation of MMPs. My results have also shown that the reaction between H2S produced by DSRs and olivine is abiotic, not catalyzed and exergonic. The pH did not vary significantly during this reaction and pH variation (in the 5-9 range) did not significantly influence this chemical reaction. Bicarbonate inhibited the reaction between H2S and olivine, but not the chemical equilibrium. Phosphate, a weak iron chelator, influenced the equilibrium of the reaction and it is assumed to help increase the rate of olivine weathering in the presence of DSRs. The activity of DSRs was positively influenced by the presence and abundance of olivine. Based on my results I propose that olivine help DSR obtain energy more efficiently, but does not represent a source of energy or nutrients for the cells. These results helped better understand the formation of iron biominerals and signatures of this activity.

Alle relevanten Informationen zu Eisenoxiden, von der Struktur und Transformation über Charakterisierungsverfahren bis hin zu den neuesten AnwendungEN. Ein Muss für alle, die in dem Fachgebiet arbeiten.

This book explains how microorganisms play a pivotal role in the formation of biominerals, including carbonates, silicate minerals and oxides. As readers will learn, these minerals may be produced either intracellularly or extracellularly in order to sustain microbial life. Experienced scientists from the field show that some of these biominerals can be produced in an active form, which involves direct enzymatic intervention to form precipitates. In addition, passive mineral formation can be mediated by the presence of dead cells. Readers from Microbiology and Biochemistry will appreciate the thorough coverage on various types of microbial mineral formation and their roles in microbial domains. Furthermore, they will benefit from the authors’ first-hand knowledge regarding common techniques for studying biomineral-producing microorganisms, factors affecting biomineralization, and the use of this process in biotechnological applications.

The interplay between Geology and Biology has shaped the Earth from the early Precambrian, 4 billion years ago. Moving beyond the borders of the classical core disciplines, Geobiology strives to identify chains of cause-and-effect and synergisms between the geo- and the biospheres that have been driving the evolution of life in modern and ancient environments. Combining modern methods, geobiological information can be extracted not only from visible remains of organisms, but also from organic molecules, rock fabrics, minerals, isotopes and other tracers. An understanding of these processes and their signatures reveals enormous applied potentials with respect to issues of environment protection, public health, energy and resource management. The Encyclopedia of Geobiology has been designed to act as a key reference for students, researchers, teachers, and the informed public and to provide basic, but comprehensible knowledge on this rapidly expanding discipline that sits at the interface between modern geo- and biosciences.

Bacteria can sequester metals and other ions intracellularly in various forms ranging from poorly ordered deposits to well- ordered mineral crystals. Magnetotactic bacteria provide one example of such intracellular deposits. They synthesize intracellular magnetic minerals of magnetite (Fe3O4) and/or greigite (Fe3S4) magnetosomes which are generally less than 150 nm and organized into one or multiple chain structures. The magnetosome chain(s) act like a compass needle to facilitate the navigation of magnetotactic bacteria by using the Earth’s magnetic field. Due to their ubiquitous distribution in aquatic and sedimentary environments, magnetotactic bacteria play important roles in global iron cycling. Other intracellular mineral phases have been evidenced in bacteria such as As2S3, CaCO3, CdS, Se(0) or various metal phosphates which may play as well a significant role in the geochemical cycle of these elements. However, in contrast to magnetotactic bacteria, the biological and environmental function of these particles remains a matter of debate. In recent years, such intracellularly biomineralizaing bacteria have become an attractive model system for investigating the molecular mechanisms of organelle-like structure formation in prokaryotic cells. The geological significance of intracellular biomineralization is important; spectacular examples are fossil magnetosomes that may significantly contribute to the bulk magnetization of sediments and act as potential archives of paleoenvironmental changes. In addition, intracellular mineral deposits formed by bacteria have potentially versatile applications in biotechnological and biomedical fields. After more than four decades of research, the knowledge on intracellularly biomineralizing bacteria has greatly improved. The aim of this Research Topic is to highlight recent advances in our understanding of intracellular biomineralization by bacteria. Magnetotactic bacteria are a system of choice for that topic but other intracellularly biomineralizing bacteria may bring a unique perspective on that process. Research papers, reviews, perspectives, and opinion papers on (i) the diversity and ecology of intracellularly biomineralizing bacteria, (ii) the molecular mechanisms of intracellular biomineralization, (iii) the chemo- and magneto-taxis behaviors of magnetotactic bacteria, (iv) the involvement of intracellularly biomineralizing bacteria in local or global biogeochemical cycling, (v) the paleoenvironmental reconstructions and paleomagnetic signals based on fossil magnetosomes, (vi) and the applications of intracellular minerals in biomaterial and biotechnology were welcomed.

The mystery of how migrating animals find their way over unfamiliar terrain has intrigued people for centuries, and has been the focus of productive research in the biological sci ences for several decades. Whether or not the earth's magnetic field had anything to do with their navigational abilities has sufaced and been dismissed several times, beginning at least in the mid to late 1800s. This topic generally remained out of the mainstream of scientific research for two reasons: (1) The apparent irreproducibility of many of the be havioral experiments which were supposed to demonstrate the existence of the magnetic sense; and (2) Perceived theoretical difficulties which were encountered when biophysi cists tried to understand how such a sensory system might operate. However, during the mid to late 1960s as the science of ethology (animal behavior) grew, it became clear from studies on bees and birds that the geomagnetic field is used under a variety of conditions. As more and more organisms were found to have similar abilities, the problem shifted back to the question as to the basis of this perception. Of the various schemes for trans ducing the geomagnetic field to the nervous system which have been proposed, the hy pothesis of magnetite-based magnetoreception discussed at length in this volume has per haps the best potential for explaining a wide range of these effects, even though this link is as yet clear only in the case of magnetotactic bacteria.

2012 PROSE Award, Earth Science: Honorable Mention For more than fifty years scientists have been concerned with the interrelationships of Earth and life. Over the past decade, however, geobiology, the name given to this interdisciplinary endeavour, has emerged as an exciting and rapidly expanding field, fuelled by advances in molecular phylogeny, a new microbial ecology made possible by the molecular revolution, increasingly sophisticated new techniques for imaging and determining chemical compositions of solids on nanometer scales, the development of non-traditional stable isotope analyses, Earth systems science and Earth system history, and accelerating exploration of other planets within and beyond our solar system. Geobiology has many faces: there is the microbial weathering of minerals, bacterial and skeletal biomineralization, the roles of autotrophic and heterotrophic metabolisms in elemental cycling, the redox history in the oceans and its relationship to evolution and the origin of life itself.. This book is the first to set out a coherent set of principles that underpin geobiology, and will act as a foundational text that will speed the dissemination of those principles. The chapters have been carefully chosen to provide intellectually rich but concise summaries of key topics, and each has been written by one or more of the leading scientists in that field.. Fundamentals of Geobiology is aimed at advanced undergraduates and graduates in the Earth and biological sciences, and to the growing number of scientists worldwide who have an interest in this burgeoning new discipline. Additional resources for this book can be found at: http://www.wiley.com/go/knoll/geobiology.

The importance of metals in biology, the environment and medicine has become increasingly evident over the last twenty five years. The study of the multiple roles of metal ions in biological systems, the rapidly expanding interface between inorganic chemistry and biology constitutes the subject called Biological Inorganic Chemistry. The present text, written by a biochemist, with a long career experience in the field (particularly iron and copper) presents an introduction to this exciting and dynamic field. The book begins with introductory chapters, which together constitute an overview of the concepts, both chemical and biological, which are required to equip the reader for the detailed analysis which follows. Pathways of metal assimilation, storage and transport, as well as metal homeostasis are dealt with next. Thereafter, individual chapters discuss the roles of sodium and potassium, magnesium, calcium, zinc, iron, copper, nickel and cobalt, manganese, and finally molybdenum, vanadium, tungsten and chromium. The final three chapters provide a tantalising view of the roles of metals in brain function, biomineralization and a brief illustration of their importance in both medicine and the environment.Relaxed and agreeable writing style. The reader will not only fiind the book easy to read, the fascinating anecdotes and footnotes will give him pegs to hang important ideas on.Written by a biochemist. Will enable the reader to more readily grasp the biological and clinical relevance of the subject.Many colour illustrations. Enables easier visualization of molecular mechanismsWritten by a single author. Ensures homgeneity of style and effective cross referencing between chapters