Calcium/calmodulin (Ca2+/CaM)-dependent protein kinase II (CaMKII) couples increases in cellular Ca2+ to fundamental responses in excitable cells. CaMKII was identified over 20 years ago by activation dependence on Ca2+/CaM, but recent evidence shows that CaMKII activity is also enhanced by pro-oxidant conditions. Here we show that oxidation of paired regulatory domain methionine residues sustains CaMKII activity in the absence of Ca2+/CaM. CaMKII is activated by angiotensin II (AngII)-induced oxidation, leading to apoptosis in cardiomyocytes both in vitro and in vivo. CaMKII oxidation is reversed by methionine sulfoxide reductase A (MsrA), and MsrA-/- mice show exaggerated CaMKII oxidation and myocardial apoptosis, impaired cardiac function, and increased mortality after myocardial infarction. Our data demonstrate a dynamic mechanism for CaMKII activation by oxidation and highlight the critical importance of oxidation-dependent CaMKII activation to AngII and ischemic myocardial apoptosis.

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The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance the persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of nondividing bacterial populations have remained obscure. Here, we demonstrate that staphylococci that enter stationary phase following growth in media supplemented with excess glucose, undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the acetate generated as a byproduct of glucose metabolism induces cytoplasmic acidification and extensive protein damage in nondividing cells. Although cell death ensues, it does not occur as a passive consequence of protein damage. Instead, we demonstrate that the expression and activity of the ClpXP protease is induced, resulting in the degeneration of cellular antioxidant capacity and, ultimately, cell death. Under these conditions, inactivation of either clpX or clpP resulted in the extended survival of unfit cells in stationary phase, but at the cost of maintaining population fitness. Finally, we show that cell death from antibiotics that interfere with bacterial protein synthesis can also be partly ascribed to the corresponding increase in clpP expression and activity. The functional conservation of ClpP in eukaryotes and bacteria suggests that ClpP-dependent cell death and fitness maintenance may be a widespread phenomenon in these domains of life.

Competency in psychodynamic psychotherapy is a requirement for residency training in psychiatry. However, for a variety of reasons, learning psychodynamic psychotherapy is difficult for residents. In this article, we share our experience in an elective in Transference-Focused Psychotherapy (TFP), a manualized treatment for severe personality disorders. Originally, this elective was conceptualized as an advanced component of training, offering specialized training in treating a subgroup of patients with severe personality disorders with a specific type of psychodynamic psychotherapy. However, contrary to the expectations of the residents and the training director, the elective in TFP strengthened understanding of core components of basic psychodynamic psychotherapy with all patients, not just those with severe personality disorders. We discuss various challenges in learning psychodynamic psychotherapy and how TFP served to address them. Two case vignettes illustrate several key points.

Under aerobic conditions, Staphylococcus aureus (S. aureus) primarily metabolizes glucose to acetic acid. Although normally S. aureus is able to re-utilize acetate as a carbon source following glucose exhaustion, significantly high levels of acetate in the culture media may not only be growth inhibitory but also potentiates cell death in stationary phase cultures by a mechanism dependent on cytoplasmic acidification. One consequence of acetic acid toxicity is the production of reactive oxygen species (ROS). The present protocol describes the detection of ROS in S. aureus undergoing cell death by electron paramagnetic resonance (EPR) spectroscopy. Using 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH) as a cell permeable spin probe, we demonstrate the detection of various oxygen radicals generated by bacteria. Although standardized for S. aureus, the methods described here should be easily adapted for other bacterial species. This protocol is adapted from Thomas et al. (2014) and Thomas et al. (2010).