Time-Dependent Amplitude Analysis of Boc→Ksπ+π- Decays with the BABAR Experiment and Constraints on the CKM Matrix Using the B →*π and B →RhoK Modes

Download or read book Time-Dependent Amplitude Analysis of Boc→Ksπ+π- Decays with the BABAR Experiment and Constraints on the CKM Matrix Using the B →*π and B →RhoK Modes written by Luis Pérez Pérez and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work aimed at studying the response of microorganisms to toxic elements, such as arsenic and to the lethal effects of mineral precipitation within cellular structures. We applied microscopic and spectroscopic tools adapted to the study of these organic-mineral assemblages. In a first section, we studied two different bacterial strains, both using Fe(II) as an electron donor under strictly anoxic conditions at neutral pH. The phototrophic strain SW2 precipitated iron on lipo-polysaccharidic fibres only at distance from the cells, whereas the denitrifying strain BoFeNl precipitated iron within its periplasm. Ultrafine cellular structures and proteins were preserved within these encrusted cells that can be considered as microfossils. In a second section, we studied unicellular eukaryotes from a Fe and As-rich acid mine drainage. Iron accumulation within the cells was shown to be completely decoupled from the processes of arsenic detoxification. Arsenic detoxification starts with As(V) reduction to As(III), followed by its complexation by thiol groups, involving the glutathione pathway and leading to its export from the cell. However, we show that As(V) was more toxic to the cells than As(III). Our results altogether provide new insights on the mechanisms of microbial biomineralization and detoxification of metals/metalloids and opens new perspectives for the search of biosignatures of specific metabolisms.