Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

No abstract

The versatility of Ca signals allows it to regulate diverse cellular processes such as migration, apoptosis, motility and exocytosis. In some receptors (e.g., VEGFR2), Ca signals are generated upon binding their ligand(s) (e.g., VEGF-A). Here, we employed a design strategy to engineer proteins that generate a Ca signal upon binding various extracellular stimuli by creating fusions of protein domains that oligomerize to the transmembrane domain and the cytoplasmic tail of the VEGFR2. To test the strategy, we created chimeric proteins that generate Ca signals upon stimulation with various extracellular stimuli (e.g., rapamycin, EDTA or extracellular free Ca). By coupling these chimeric proteins that generate Ca signals with proteins that respond to Ca signals, we rewired, for example, dynamic cellular blebbing to increases in extracellular free Ca. Thus, using this design strategy, it is possible to engineer proteins to generate a Ca signal to rewire a wide range of extracellular stimuli to a wide range of Ca-activated processes.

Since the removal of senescent cells in model organisms has been linked to rejuvenation and increased lifespan, senotherapies have emerged to target senescent cells for death. In particular, interleukin-6 (IL6) is a prominent senescence-associated secretory phenotype (SASP) and, thus, seeking IL6 could potentially localize engineered cells to senescent cells for therapeutic intervention. Here, we engineered a chimeric IL6 receptor (IL6Rchi) that generates a Ca signal in response to IL6 stimulation. When IL6Rchi was co-expressed with an engineered Ca-activated RhoA (CaRQ), it enabled directed migration to IL6 in cells that have no such natural ability. Next, the removal of target cells was accomplished by the mechanism of membrane fusion and subsequent death. This work represents a first step towards engineering a cell to target senescent cells that secrete high levels of IL6. For increased specificity to senescent cells, it will likely be necessary for an engineered cell to recognize multiple SASPs simultaneously.

The Ca signaling toolkit is the set of proteins used by living systems to generate and respond to Ca signals. The selective expression of these proteins in particular tissues, cell types and subcellular locations allows the Ca signal to regulate a diverse set of cellular processes. Through synthetic biology, the Ca signaling toolkit can be expanded beyond the natural repertoire to potentially allow a non-natural ligand to control downstream cellular processes. To realize this potential, we exploited the ability of an antibody to bind its antigen exclusively in combination with the ability of the cytoplasmic domain of vascular endothelial growth factor receptor 2 (VEGFR2) to generate a Ca signal upon oligomerization. Using protein fusions between antibody variants (i.e., nanobody, single-chain antibody and the monoclonal antibody) and the VEGFR2 cytoplasmic domain, Ca signals were generated in response to extracellular stimulation with green fluorescent protein, mCherry, tumor necrosis factor alpha and soluble CD14. The Ca signal generation by the stimulus did not require a stringent transition from monomer to oligomer state, but instead only required an increase in the oligomeric state. The Ca signal generated by these classes of antibody-based fusion proteins can be rewired with a Ca indicator or with an engineered Ca activated RhoA to allow for antigen screening or migration to most extracellular ligands, respectively.