Agricultural breadbaskets shift poleward given adaptive farmer behavior under climate change

Modern food production is spatially concentrated in global “breadbaskets.” A major unresolved question is whether these peak production regions will shift poleward as the climate warms, allowing some recovery of potential climate-related losses. While agricultural impacts studies to date have focused on currently cultivated land, the Global Gridded Crop Model Intercomparison Project (GGCMI) Phase 2 experiment allows us to assess changes in both yields and the location of peak productivity regions under warming. We examine crop responses under projected end of century warming using seven process-based models simulating five major crops (maize, rice, soybeans, and spring and winter wheat) with a variety of adaptation strategies. We find that in no-adaptation cases, when planting date and cultivar choices are held fixed, regions of peak production remain stationary and yield losses can be severe, since growing seasons contract strongly with warming. When adaptations in management practices are allowed (cultivars that retain growing season length under warming and modified planting dates), peak productivity zones shift poleward and yield losses are largely recovered. While most growing-zone shifts are ultimately limited by geography, breadbaskets studied here move poleward over 600 km on average by end of the century under RCP 8.5. These results suggest that agricultural impacts assessments can be strongly biased if restricted in spatial area or in the scope of adaptive behavior considered. Accurate evaluation of food security under climate change requires global modeling and careful treatment of adaptation strategies.     

Disrupted‐in‐schizophrenia 1 functional polymorphisms and D2/D3 receptor availability: A [11C]‐(+)‐PHNO imaging study

The disrupted‐in‐schizophrenia 1 (DISC1) protein has been implicated in a range of biological mechanisms underlying chronic mental disorders such as schizophrenia. Schizophrenia is associated with abnormal striatal dopamine signalling, and all antipsychotic drugs block striatal dopamine 2/3 receptors (D_2/3Rs). Importantly, the DISC1 protein directly interacts and forms a protein complex with the dopamine D₂ receptor (D₂R) that inhibits agonist‐induced D₂R internalisation. Moreover, animal studies have found large striatal increases in the proportion of D₂R receptors in a high affinity state (D₂^highR) in DISC1 rodent models. Here, we investigated the relationship between the three most common polymorphisms altering the amino‐acid sequence of the DISC1 protein (Ser704Cys (rs821616), Leu607Phe (rs6675281) and Arg264Gln (rs3738401)) and striatal D_2/3R availability in 41 healthy human volunteers, using [¹¹C]‐(+)‐PHNO positron emission tomography. We found no association between DISC1 polymorphisms and D_2/3R availability in the striatum and D₂R availability in the caudate and putamen. Therefore, despite a direct interaction between DISC1 and the D₂R, none of its main functional polymorphisms impact striatal D_2/3R binding potential, suggesting DISC1 variants act through other mechanisms.     

Balancing Light Absorption and Charge Transport in Vertical SnS2 Nanoflake Photoanodes with Stepped Layers and Large Intrinsic Mobility

Significant optical absorption in the blue–green spectral range, high intralayer carrier mobility, and band alignment suitable for water splitting suggest tin disulfide (SnS₂) as a candidate material for photo‐electrochemical applications. In this work, vertically aligned SnS₂ nanoflakes are synthesized directly on transparent conductive substrates using a scalable close space sublimation (CSS) method. Detailed characterization by time‐resolved terahertz and time‐resolved photoluminescence spectroscopies reveals a high intrinsic carrier mobility of 330 cm² V^?1 s^?1 and photoexcited carrier lifetimes of 1.3 ns in these nanoflakes, resulting in a long vertical diffusion length of ≈1 µm. The highest photo‐electrochemical performance is achieved by growing SnS₂ nanoflakes with heights that are between this diffusion length and the optical absorption depth of ≈2 µm, which balances the competing requirements of charge transport and light absorption. Moreover, the unique stepped morphology of these CSS‐grown nanoflakes improves photocurrent by exposing multiple edge sites in every nanoflake. The optimized vertical SnS₂ nanoflake photoanodes produce record photocurrents of 4.5 mA cm^?2 for oxidation of a sulfite hole scavenger and 2.6 mA cm^?2 for water oxidation without any hole scavenger, both at 1.23 V_RHE in neutral electrolyte under simulated AM1.5G sunlight, and stable photocurrents for iodide oxidation in acidic electrolyte.     

Regulation of autotaxin expression and secretion by lysophosphatidate and sphingosine 1-phosphate

Autotaxin (ATX) is a secreted enzyme, which produces extracellular lysophosphatidate (LPA) from lysophosphatidylcholine (LPC). LPA activates six G protein-coupled receptors and this is essential for vasculogenesis during embryonic development. ATX is also involved in wound healing and inflammation, and in tumor growth, metastasis, and chemo-resistance. It is, therefore, important to understand how ATX is regulated. It was proposed that ATX activity is inhibited by its product LPA, or a related lipid called sphingosine 1-phosphate (S1P). We now show that this apparent inhibition is ineffective at the high concentrations of LPC that occur in vivo. Instead, feedback regulation by LPA and S1P is mediated by inhibition of ATX expression resulting from phosphatidylinositol-3-kinase activation. Inhibiting ATX activity in mice with ONO-8430506 severely decreased plasma LPA concentrations and increased ATX mRNA in adipose tissue, which is a major site of ATX production. Consequently, the amount of inhibitor-bound ATX protein in the plasma increased. We, therefore, demonstrate the concept that accumulation of LPA in the circulation decreases ATX production. However, this feedback regulation can be overcome by the inflammatory cytokines, TNF-α or interleukin 1β. This enables high LPA and ATX levels to coexist in inflammatory conditions. The results are discussed in terms of ATX regulation in wound healing and cancer.     

LLY-507, a Cell-active,Potent, and Selective Inhibitor of Protein-lysine Methyltransferase SMYD2

SMYD2 is a lysine methyltransferase that catalyzes the monomethylation of several protein substrates including p53. SMYD2 is overexpressed in a significant percentage of esophageal squamous primary carcinomas, and that overexpression correlates with poor patient survival. However, the mechanism(s) by which SMYD2 promotes oncogenesis is not understood. A small molecule probe for SMYD2 would allow for the pharmacological dissection of this biology. In this report, we disclose LLY-507, a cell-active, potent small molecule inhibitor of SMYD2. LLY-507 is >100-fold selective for SMYD2 over a broad range of methyltransferase and non-methyltransferase targets. A 1.63-Å resolution crystal structure of SMYD2 in complex with LLY-507 shows the inhibitor binding in the substrate peptide binding pocket. LLY-507 is active in cells as measured by reduction of SMYD2-induced monomethylation of p53 Lys³⁷⁰ at submicromolar concentrations. We used LLY-507 to further test other potential roles of SMYD2. Mass spectrometry-based proteomics showed that cellular global histone methylation levels were not significantly affected by SMYD2 inhibition with LLY-507, and subcellular fractionation studies indicate that SMYD2 is primarily cytoplasmic, suggesting that SMYD2 targets a very small subset of histones at specific chromatin loci and/or non-histone substrates. Breast and liver cancers were identified through in silico data mining as tumor types that display amplification and/or overexpression of SMYD2. LLY-507 inhibited the proliferation of several esophageal, liver, and breast cancer cell lines in a dose-dependent manner. These findings suggest that LLY-507 serves as a valuable chemical probe to aid in the dissection of SMYD2 function in cancer and other biological processes.     

Physiology,Genomics, and Pathway Engineering of an Ethanol-Tolerant Strain of Clostridium phytofermentans

Novel processing strategies for hydrolysis and fermentation of lignocellulosic biomass in a single reactor offer large potential cost savings for production of biocommodities and biofuels. One critical challenge is retaining high enzyme production in the presence of elevated product titers. Toward this goal, the cellulolytic, ethanol-producing bacterium Clostridium phytofermentans was adapted to increased ethanol concentrations. The resulting ethanol-tolerant (ET) strain has nearly doubled ethanol tolerance relative to the wild-type level but also reduced ethanol yield and growth at low ethanol concentrations. The genome of the ET strain has coding changes in proteins involved in membrane biosynthesis, the Rnf complex, cation homeostasis, gene regulation, and ethanol production. In particular, purification of the mutant bifunctional acetaldehyde coenzyme A (CoA)/alcohol dehydrogenase showed that a G609D variant abolished its activities, including ethanol formation. Heterologous expression of Zymomonas mobilis pyruvate decarboxylase and alcohol dehydrogenase in the ET strain increased cellulose consumption and restored ethanol production, demonstrating how metabolic engineering can be used to overcome disadvantageous mutations incurred during adaptation to ethanol. We discuss how genetic changes in the ET strain reveal novel potential strategies for improving microbial solvent tolerance.