Toxoplasma-induced changes in host risk behaviour are independent of parasite-derived AaaH2 tyrosine hydroxylase.

Toxoplasma gondii infects a broad range of hosts and can establish chronic infections with the formation of brain cysts. Infected animals show altered risk behaviour which has been suggested to increase capture probability of hosts, and thus enhance parasite transmission. It has been proposed that the ability of Toxoplasma cysts to secrete tyrosine hydroxylase could mediate these behavioural alterations.

The Spatiotemporal Organization of the Striatum Encodes Action Space.

Activity in striatal direct- and indirect-pathway spiny projection neurons (SPNs) is critical for proper movement. However, little is known about the spatiotemporal organization of this activity. We investigated the spatiotemporal organization of SPN ensemble activity in mice during self-paced, natural movements using microendoscopic imaging.

Chronic Toxoplasma infection modifies the structure and the risk of host behavior.

The intracellular parasite Toxoplasma has an indirect life cycle, in which felids are the definitive host. It has been suggested that this parasite developed mechanisms for enhancing its transmission rate to felids by inducing behavioral modifications in the intermediate rodent host. For example, Toxoplasma-infected rodents display a reduction in the innate fear of predator odor.

Revealing the structural origin of the redox-Bohr effect: the first solution structure of a cytochrome from Geobacter sulfurreducens.

Gs (Geobacter sulfurreducens) can transfer electrons to the exterior of its cells, a property that makes it a preferential candidate for the development of biotechnological applications. Its genome encodes over 100 cytochromes and, despite their abundance and key functional roles, to date there is no structural information for these proteins in solution. The trihaem cytochrome PpcA might have a crucial role in the conversion of electronic energy into protonmotive force, a fundamental step for ATP synthesis in the presence of extracellular electron acceptors.

Backbone, side chain and heme resonance assignments of the triheme cytochrome PpcA from Geobacter sulfurreducens.

Gene knock-out studies on Geobacter sulfurreducens cells showed that the periplasmic triheme cytochrome PpcA is involved in respiratory pathways leading to the extracellular reduction of Fe(III) and U(VI) oxides. The crucial role of this protein in bridging the electron transfer between the cytoplasm and cell exterior was further supported by proteomics studies. In comparison with non-heme proteins, the presence of numerous proton-containing groups in the heme groups causes additional challenges to the full protein assignment and structure calculation.

Redox linked conformational changes in cytochrome c3 from Desulfovibrio desulfuricans ATCC 27774.

Cytochrome c3 from Desulfovibrio desulfuricans ATCC 27774 appears to be capable of receiving two protons and two electrons from hydrogenase for transport to the membrane, and converting electronic energy into proton motive force. Detailed studies of the mechanism require control both of the redox state and of the protonation state of the protein; hence, structure determination of the protein in solution by NMR is the preferred method. This work compares the structures of the protonated protein in the fully oxidized and fully reduced states as a first step toward elucidating the pH-dependent and redox-state-dependent conformational changes that drive the energy transduction.

The solution structure of a tetraheme cytochrome from Shewanella frigidimarina reveals a novel family structural motif.

The bacteria belonging to the genus Shewanella are facultative anaerobes that utilize a variety of terminal electron acceptors which includes soluble and insoluble metal oxides. The tetraheme c-type cytochrome isolated during anaerobic growth of Shewanella frigidimarina NCIMB400 ( Sfc) contains 86 residues and is involved in the Fe(III) reduction pathways. Although the functional properties of Sfc redox centers are quite well described, no structures are available for this protein.