Insights into substrate recognition and export tunnel preferences in the efflux transporter AcrB.

In Escherichia coli AcrB is a major multidrug exporter, which confers the bacterium resistance to many antibiotics with diverse structural and chemical proprieties. Studies have identified three possible tunnels (or channels) within AcrB that different substrates use before reaching the distal pocket, from which they are subsequently extruded. Recently, we reported that mutations in the AcrB gate loop may affect the conformational change kinetics involved in substrate export rather than directly affecting molecular interactions with this loop, and we highlighted the distinct export tunnel preferences between erythromycin and doxorubicin.

Evolutions in cardiac and gonadal ultra-structure during a "cycle" of androgenic anabolic abuse in adult male mice.

Background: The importance of the present study comes from the lack of sufficient information about the reversibility of the potential histopathological alterations which may result from anabolic androgenic drugs abuse by "Cycling" protocol. So, the aim of this study is to explore the negative effects of Deca-Durabolin abuse in cardiac and gonadal ultra-structures during an administration cycle.

Methods: For our purpose, study was performed on 40 male adult mices.

IMU-based sensor-to-segment multiple calibration for upper limb joint angle measurement-a proof of concept.

A lot of attention has been paid to wearable inertial sensors regarded as an alternative solution for outdoor human motion tracking. Relevant joint angles can only be calculated from anatomical orientations, but they are negatively impacted by soft tissue artifact (STA) defined as skin motion with respect to the underlying bone; the accuracy of measured joint angle during movement is affected by the ongoing misalignment of the sensor. In this work, a new sensor-to-segment calibration using inertial measurement units is proposed.

New insights into the structural and functional involvement of the gate loop in AcrB export activity.

AcrB is a major multidrug exporter in Escherichia coli and other Gram-negative bacteria. Its gate loop, located between the proximal and the distal pockets, have been reported to play important role in the export of many antibiotics. This loop location, rigidity and interactions with substrates have led recent reports to suggest that AcrB export mechanism operates in a sequential manner.

On the Ca binding and conformational change in EF-hand domains: Experimental evidence of Ca-saturated intermediates of N-domain of calmodulin.

Double mutation of Q41L and K75I in the N-domain of calmodulin (N-Cam) stabilizes the closed form of N-Cam such that binding of Ca in solution no longer triggers a conformational change to the open form, and its Ca binding affinity decreases dramatically. To further investigate the solvation effects on the structure, Ca binding affinity and conformational dynamics of this N-Cam double mutant in the Ca saturated state, we solved its X-ray structure. Surprisingly, the structure revealed an open conformation of the domain which contradicts its closed conformation in solution.