The Rotating Front Row Increases Student-Reported Participation during Discussion.

Discussion is a common method to engage students in large-enrollment lectures. Many instructors rely on voluntary participation from students, which can lead to inequitable student contributions and exposure to a narrow scope of opinions. Mandatory participation for which points are earned or lost can lead to student disengagement and have the unintended consequence of marginalizing students.

Structure of a mutant β toxin from Staphylococcus aureus reveals domain swapping and conformational flexibility.

The 3.35 Å resolution crystal structure of a mutant form of the staphylococcal sphingomyelinase β toxin in which a conserved hydrophobic β-hairpin has been deleted is reported. It is shown that this mutation induces domain swapping of a C-terminal β-strand, leading to the formation of dimers linked by a conformationally flexible hinge region.

FimL regulates cAMP synthesis in Pseudomonas aeruginosa.

Pseudomonas aeruginosa, a ubiquitous bacteria found in diverse ecological niches, is an important cause of acute infections in immunocompromised individuals and chronic infections in patients with Cystic Fibrosis. One signaling molecule required for the coordinate regulation of virulence factors associated with acute infections is 3', 5'-cyclic adenosine monophosphate, (cAMP), which binds to and activates a catabolite repressor homolog, Vfr. Vfr controls the transcription of many virulence factors, including those associated with Type IV pili (TFP), the Type III secretion system (T3SS), the Type II secretion system, flagellar-mediated motility, and quorum sensing systems.

Beta toxin catalyzes formation of nucleoprotein matrix in staphylococcal biofilms.

Biofilms are surface-associated communities of microbes encompassed by an extracellular matrix. It is estimated that 80% of all bacterial infections involve biofilm formation, but the structure and regulation of biofilms are incompletely understood. Extracellular DNA (eDNA) is a major structural component in many biofilms of the pathogenic bacterium Staphylococcus aureus, but its role is enigmatic.

Structure and biological activities of beta toxin from Staphylococcus aureus.

Beta toxin is a neutral sphingomyelinase secreted by certain strains of Staphylococcus aureus. This virulence factor lyses erythrocytes in order to evade the host immune system as well as scavenge nutrients. The structure of beta toxin was determined at 2.