Self-initiating and applying episodic foresight in middle childhood.

This study provides an important extension to the growing literature on prospection in children by providing the first test of whether one's ability to engage in the functional (as opposed to the purely phenomenological) aspect of episodic foresight improves across middle childhood. Of the various forms of prospection, episodic foresight has been proposed to be one of the most flexible and functionally powerful, defined as the ability to not only imagine future events (simulative aspect) but also use those imaginings to guide behavior in the present (functional aspect). The current study tested 80 typically developing children aged 8 to 12 years using an extensive cognitive battery comprising Virtual Week Foresight, the Autobiographical Interview, and a series of crystallized and fluid intelligence measures. Whereas data indicated age-related improvements in detecting future-oriented problems and taking steps in the present in service of solving these, all children in this age bracket demonstrated a similar capacity for problem resolution (i.e., the ability to subsequently solve successfully identified problems). Results also revealed the importance of broader crystallized and fluid intelligence, but not episodic memory or episodic future thinking, in engaging in this capacity. Research is now required to understand the real-life consequences of episodic foresight during this developmental period as well as the ways in which parents and teachers can help to foster this capacity and consequently help to support children's growing desire for independence during this time.

Predicting and Experimentally Validating Hot-Spot Residues at Protein-Protein Interfaces.

Protein-protein interactions (PPIs) are vital to all biological processes. These interactions are often dynamic, sometimes transient, typically occur over large topographically shallow protein surfaces, and can exhibit a broad range of affinities. Considerable progress has been made in determining PPI structures. However, given the above properties, understanding the key determinants of their thermodynamic stability remains a challenge in chemical biology. An improved ability to identify and engineer PPIs would advance understanding of biological mechanisms and mutant phenotypes and also provide a firmer foundation for inhibitor design. In silico prediction of PPI hot-spot amino acids using computational alanine scanning (CAS) offers a rapid approach for predicting key residues that drive protein-protein association. This can be applied to all known PPI structures; however there is a trade-off between throughput and accuracy. Here we describe a comparative analysis of multiple CAS methods, which highlights effective approaches to improve the accuracy of predicting hot-spot residues. Alongside this, we introduce a new method, BUDE Alanine Scanning, which can be applied to single structures from crystallography and to structural ensembles from NMR or molecular dynamics data. The comparative analyses facilitate accurate prediction of hot-spots that we validate experimentally with three diverse targets: NOXA-B/MCL-1 (an α-helix-mediated PPI), SIMS/SUMO, and GKAP/SHANK-PDZ (both ß-strand-mediated interactions). Finally, the approach is applied to the accurate prediction of hot-spot residues at a topographically novel Affimer/BCL-xL protein-protein interface.

The relationship between episodic future thinking and prospective memory in middle childhood: Mechanisms depend on task type.

Episodic future thinking (EFT), the ability to imagine experiencing a future event, and prospective memory (PM), the ability to remember and carry out a planned action, are core aspects of future-oriented cognition that have individually been the focus of research attention in the developmental literature. However, the relationship between EFT and PM, including the extent to which it varies with PM task type, remains poorly delineated, particularly in middle childhood. The current study tested this relationship in 62 typically developing children aged 8-12 years. Results indicated that EFT ability was significantly related to performance on three types of PM tasks (regular and irregular event based and regular time based). Age was not found to moderate the relationship. Children's performance on the retrospective memory component of the PM tasks mediated the relationship between EFT ability and their performance on three types of PM tasks. For irregular event-based tasks, however, EFT made an additional significant contribution. This study adds to the limited empirical literature supporting a relationship between EFT and PM in this age band and supports theoretical models arguing that EFT ability may support PM performance by strengthening the encoding of PM task details in retrospective memory. However, additional mechanisms were also indicated for irregular event-based PM tasks, possibly involving strengthening of cue-context associations. These data show for the first time that the contribution of EFT to children's PM performance varies across task types. This study provides an important and novel contribution to current understanding of the processes that underlie PM development.

De novo coiled-coil peptides as scaffolds for disrupting protein-protein interactions.

Protein-protein interactions (PPIs) play pivotal roles in the majority of biological processes. Therefore, improved approaches to target and disrupt PPIs would provide tools for chemical biology and leads for therapeutic development. PPIs with α-helical components are appealing targets given that the secondary structure is well understood and can be mimicked or stabilised to render small-molecule and constrained-peptide-based inhibitors. Here we present a strategy to target α-helix-mediated PPIs that exploits de novo coiled-coil assemblies and test this using the MCL-1/NOXA-B PPI. First, computational alanine scanning is used to identify key α-helical residues from NOXA-B that contribute to the interface. Next, these residues are grafted onto the exposed surfaces of de novo designed homodimeric or heterodimeric coiled-coil peptides. The resulting synthetic peptides selectively inhibit a cognate MCL-1/BID complex in the mid-nM range. Furthermore, the heterodimeric system affords control as inhibition occurs only when both the grafted peptide and its designed partner are present. This establishes proof of concept for exploiting peptides stabilised in de novo coiled coils as inhibitors of PPIs. This dependence on supramolecular assembly introduces new possibilities for regulation and control.

Retrospective Review of the Anaesthetic Management of Maxillectomies and Mandibulectomies for Benign Tumours in Sub-Saharan Africa.

BACKGROUND: Safe anaesthesia is a crucial component of safe surgical care, yet anaesthetic complications are common in resource-limited settings. We describe differences in anaesthetic needs for Mandibulectomy vs. Maxillectomy in three sub-Saharan African countries. MATERIALS AND METHODS: Retrospective review of patients undergoing minor Mandibulectomy, major Mandibulectomy, or Maxillectomy in Togo, Guinea and Republic of the Congo. Surgeries were performed on the Africa Mercy, an international non-governmental hospital ship. Primary outcomes were need for advanced airway management and intra-operative blood loss. Secondary outcomes were time under general anaesthesia and hospital length of stay. Multivariate regression determined the association between operation type and each outcome measure. RESULTS: 105 patients were included (25 minor Mandibulectomy, 58 major Mandibulectomy, 22 Maxillectomy procedures). In-hospital mortality was 0%. 44/105 (41.9%) required an advanced airway management technique to achieve intubation, although in all cases this was anticipated prior to the procedure; no differences were noted between surgical procedure (p = 0.72). Operative procedure was a significant risk factor for intra-operative blood loss. Patients undergoing Maxillectomy lost on average 851.5 (413.3, 1289.8, p = 0.0003) mL more blood than patients undergoing minor Mandibulectomy, and 507.3 (150.3, 864.3, p = 0.007) mL more blood than patients undergoing major Mandibulectomy. Patients undergoing Maxillectomy had a significantly higher time under general anaesthesia than those undergoing minor Mandibulectomy. There was no significant difference in hospital length of stay between operation type. CONCLUSION: Anaesthetic considerations for minor Mandibulectomy, major Mandibulectomy, and Maxillectomy differ with respect to intra-operative blood loss and time under general anaesthesia, but not need for advanced airway management or length of stay. Although advanced airway management was required in 41.9% of patients, there were no unanticipated difficult airways. With appropriate training and resources, safe anaesthesia can be delivered to patients from low-income countries requiring major head and neck surgery.

Strain-promoted reaction of 1,2,4-triazines with bicyclononynes.

Strain-promoted inverse electron-demand Diels-Alder cycloaddition (SPIEDAC) reactions between 1,2,4,5-tetrazines and strained dienophiles, such as bicyclononynes, are among the fastest bioorthogonal reactions. However, the synthesis of 1,2,4,5-tetrazines is complex and can involve volatile reagents. 1,2,4-Triazines also undergo cycloaddition reactions with acyclic and unstrained dienophiles at elevated temperatures, but their reaction with strained alkynes has not been described. We postulated that 1,2,4-triazines would react with strained alkynes at low temperatures and therefore provide an alternative to the tetrazine cycloaddition reaction for use in in vitro or in vivo labelling experiments. We describe the synthesis of a 1,2,4-triazin-3-ylalanine derivative fully compatible with the fluorenylmethyloxycarbonyl (Fmoc) strategy for peptide synthesis and demonstrate its reaction with strained bicyclononynes at 37 °C with rates comparable to the reaction of azides with the same substrates. The synthetic route to triazinylalanine is readily adaptable to late-stage functionalization of other probe molecules, and the 1,2,4-triazine-SPIEDAC therefore has potential as an alternative to tetrazine cycloaddition for applications in cellular and biochemical studies.

Evaluation of the interaction between phosphohistidine analogues and phosphotyrosine binding domains.

We have investigated the interaction of peptides containing phosphohistidine analogues and their homologues with the prototypical phosphotyrosine binding SH2 domain from the eukaryotic cell signalling protein Grb2 by using a combination of isothermal titration calorimetry and a fluorescence anisotropy competition assay. These investigations demonstrated that the triazole class of phosphohistidine analogues are capable of binding too, suggesting that phosphohistidine could potentially be detected by this class of proteins in vivo.

Infection biology of a novel alpha-crystallin of Mycobacterium tuberculosis: Acr2.

Heat shock proteins assist the survival of Mycobacterium tuberculosis (MTB) but also provide a signal to the immune response. The gene most strongly induced by heat shock in MTB is Rv0251c, which encodes Acr2, a novel member of the alpha-crystallin family of molecular chaperones. The expression of acr2 increased within 1 h after infection of monocytes or macrophages, reaching a peak of 18- to 55-fold by 24 h. Inhibition of superoxide action reduced the intracellular increase in acr2. Despite this contribution to the stress response of MTB, the gene for acr2 appears dispensable; a deletion mutant (Deltaacr2) was unimpaired in log phase growth and persisted in IFN-gamma-activated human macrophages. Acr2 protein was strongly recognized by cattle with early primary Mycobacterium bovis infection and by healthy MTB-sensitized people. Within the latter group, those with recent exposure to infectious tuberculosis had, on average, 2.6 times the frequency of Acr2-specific IFN-gamma-secreting T cells than those with more remote exposure (p = 0.009). These data show that, by its up-regulation early after entry to cells, Acr2 gives away the presence of MTB to the immune response. The demonstration that there is infection stage-specific immunity to tuberculosis has implications for vaccine design.