Computational enzyme design holds promise for the production of renewable fuels, drugs and chemicals. De novo enzyme design has generated catalysts for several reactions, but with lower catalytic ...efficiencies than naturally occurring enzymes. Here we report the use of game-driven crowdsourcing to enhance the activity of a computationally designed enzyme through the functional remodeling of its structure. Players of the online game Foldit were challenged to remodel the backbone of a computationally designed bimolecular Diels-Alderase to enable additional interactions with substrates. Several iterations of design and characterization generated a 24-residue helix-turn-helix motif, including a 13-residue insertion, that increased enzyme activity >18-fold. X-ray crystallography showed that the large insertion adopts a helix-turn-helix structure positioned as in the Foldit model. These results demonstrate that human creativity can extend beyond the macroscopic challenges encountered in everyday life to molecular-scale design problems.
Summary
A wealth of knowledge exists on the response of soil processes to variation in environmental factors such as temperature and moisture, but the response from the soil microbial communities ...that control these processes remains poorly understood. We carried out a full factorial incubation experiment to investigate the single and interactive effects of temperature (10, 17, 24, 31 and 38°C) and moisture (20, 40, 60, 80 and 100% water holding capacity (WHC)) on composition of the soil microbial community characterized by the phospholipid fatty acids (PLFAs) method. The single and interactive effects of temperature and moisture were statistically significant (P < 0.05) for almost all the selected PLFA signatures, including fungi (F), bacteria (B), Gram‐positive bacteria (G+), Gram‐negative bacteria (G−), actinomycetes (ACT) and the bacterial stress index (BSI). Although the F/B ratio increased and the G+/G− ratio decreased with increasing temperature, they were not significantly affected by moisture and its interaction with temperature. In general, the concentrations of fungal PLFAs were smaller at higher temperatures, but not altered by changes in moisture. In contrast, the concentrations of bacterial PLFAs were larger at higher temperatures and moderate moisture contents. Although we manipulated temperature and moisture in the incubation, the treatments and the treatment‐altered soil properties (dissolved organic carbon (DOC) and inorganic nitrogen (ION)) together explained 18% of the total variation in selected PLFA signatures and the temperature effect contributed the most (12%). Significant correlations between community composition variables (F, B and F/B) and soil properties (DOC and ION) indicated substantive indirect effects of temperature and moisture on the composition of the soil microbial community by altering substrate availability. Our results suggest that soil microbial communities might shift towards a more bacteria‐dominated composition under warmer temperatures and moderate moisture conditions in subtropical forest regions.
Highlights
How do temperature and moisture independently and interactively affect soil microbial community composition?
Concentrations of bacterial PLFAs were larger at higher temperatures and moderate moisture.
Concentrations of fungal PLFAs were smaller at higher temperatures, but did not respond to moisture differences.
Increased soil carbon and nitrogen availability mainly benefitted bacteria under higher temperatures and moderate moisture.
In this study, we investigate the formation predictability of Hurricane Sandy (2012) with a global mesoscale model. We first present five track and intensity forecasts of Sandy initialized at 00Z ...22–26 October 2012, realistically producing its movement with a northwestward turn prior to its landfall. We then show that three experiments initialized at 00Z 16–18 October captured the genesis of Sandy with a lead time of up to 6 days and simulated reasonable evolution of Sandy's track and intensity in the next 2 day period of 18Z 21–23 October. Results suggest that the extended lead time of formation prediction is achieved by realistic simulations of multiscale processes, including (1) the interaction between an easterly wave and a low‐level westerly wind belt (WWB) and (2) the appearance of the upper‐level trough at 200 hPa to Sandy's northwest. The low‐level WWB and upper‐level trough are likely associated with a Madden‐Julian Oscillation.
Key Points
A GMM produced a remarkable 7‐day track and intensity forecast of TC SandySandy's genesis was realistically simulated with a lead time of up to six daysThe lead time is attributed to the improved simulations of multiscale systems
Ammonia intercalated flower-like MoS2 electrocatalyst film assembled by vertical orientated ultrathin nanosheet on graphite sheethas been successfully synthesized using one-step hydrothermal method. ...In this strategy, ammonia can effectively insert into the parallel plane of the MoS2 nanosheets, leading to the expansion of lattice and phase transfer from 2H to 1T, generating more active unsaturated sulfur atoms. The flower-like ammoniated MoS2 electrocatalysts with more active sites and large surface area exhibited excellent HER activity with a small Tafel slope and low onset overpotential, resulting a great enhancement in hydrogen evolution. The high efficient activity and recyclable utilization, as well as large-scale, indicate that it is a very promising electrocatalyst to replace Pt in industry application.
An experimental study was conducted on the cooling of portable hand-held electronic devices using n-eicosane as the phase change material (PCM) placed inside heat sinks with and without internal ...fins. The effects of the PCM, number of fins, orientation of the device, and the power level (ranging from 3 to 5
W), on the transient thermal performances were investigated under frequent, heavy and light usage conditions. The results indicated that PCM-based heat sinks with internal fins are viable options for cooling mobile devices but the effectiveness of the approach may require optimization with respect to the amount of PCM used, the number of fins, the power level of the heat source, and the usage mode of the device.
The present study aimed to investigate the potential role of microRNA-141-3p (miR-141-3p) in chronic inflammatory pain (CIP) by targeting the high-mobility group box1 (HMGB1) gene. In the in vitro ...study, BV2 microglial cells were selected and assigned into blank, lipopolysaccharide (LPS), miR-141-3p mimics, mimics control, miR-141-3p inhibitor, inhibitor control, miR-141-3p mimics+LPS, mimics control+ LPS, miR-141-3p inhibitor+LPS and inhibitor control+LPS groups. Ninety-six rats were randomly divided into 8 groups (12 rats in each group): blank control, model control, negative control (NC), miR-141-3p mimics+ complete Freund's adjuvant (CFA), mimics control+CFA, HMGB1 short hairpin RNA (shRNA)+CFA, HMGB1 NC+CFA and miR-141-3p mimics+HMGB1 shRNA+CFA groups. The quantitative real-time PCR, western blotting, enzyme-linked immunosorbent assay and pain behavioral test were used to measure the miR-141-3p and HMGB1 mRNA expressions, HMGB1 protein expression, inflammatory cytokines levels, and thermal and mechanical pain thresholds, respectively. Compared with the blank, mimics control, inhibitor control and miR-141-3p mimics+LPS groups, the miR-141-3p mimics group had increased miR-141-3p expression and interleukin (IL)-10 levels, and had decreased mRNA and protein expressions of HMGB1 and the levels of IL-1β, tumor necrosis factor-α (TNF-α) and IL-6, whereas the opposite trend were found in the LPS, miR-141-3p inhibitor, mimics control+LPS and inhibitor control+LPS groups. Compared with the LPS, miR-141-3p inhibitor, mimics control+LPS and inhibitor control+LPS groups, the miR141-3p+LPS group had an obviously decreased expression of miR-141-3p and IL-10, increased mRNA and protein expressions of HMGB1 and the levels of IL-1β, TNF-α and IL-6. Compared with the rats in the blank control group, the miR-141-3p expression, IL-10 level, and thermal and mechanical pain thresholds decreased significantly, whereas the mRNA and protein expressions of HMGB1, IL-1β, TNF-α and IL-6 increased significantly in rats in the NC, mimics control+CFA and HMGB1 NC+ CFA groups. The miR-141-3p expression was increased in rats in the miR-141-3p mimics+HMGB1 shRNA+CFA group. Our study demonstrated that miR-141-3p can alleviate the CIP by downregulating the downstream target gene HMGB1.
A composite plate of Mg alloy (AZ31B) and an Al alloy (7075) was fabricated by explosive welding. The microstructure and properties of the bonding interface after explosive cladding were ...investigated. The results show that the bonding interface had a wavy appearance with solidified melts in a regularly spaced pattern of discrete regions. Adiabatic shear bands and twin structure were found on the AZ31B Mg alloy side. “Metallurgical bonding” of the explosive welding interface was achieved by local diffusion with an approximate 3.5
μm thick diffusion layer. No intermetallics were formed. Shear strength across the bonding interface of AZ31B/7075 composite was ca. 70
MPa. The maximum bending stress reached 670
MPa.
Shape complementarity is an important component of molecular recognition, and the ability to precisely adjust the shape of a binding scaffold to match a target of interest would greatly facilitate ...the creation of high-affinity protein reagents and therapeutics. Here we describe a general approach to control the shape of the binding surface on repeat-protein scaffolds and apply it to leucine-rich-repeat proteins. First, self-compatible building-block modules are designed that, when polymerized, generate surfaces with unique but constant curvatures. Second, a set of junction modules that connect the different building blocks are designed. Finally, new proteins with custom-designed shapes are generated by appropriately combining building-block and junction modules. Crystal structures of the designs illustrate the power of the approach in controlling repeat-protein curvature.
The Jülich-Bonn dynamical coupled-channel approach is extended to include
K
Σ
photoproduction off the proton. Differential cross section and (double) polarization data for
K
+
Σ
0
and
K
0
Σ
+
are ...analysed simultaneously with the pion- and photon-induced production of
π
N
,
η
N
,
K
Λ
, and
K
Σ
final states, totaling almost 72,000 data points for center-of-mass energies
W
<
2.4
GeV. Based on the fit results the spectrum of
N
∗
and
Δ
resonances is extracted in terms of pole positions and residues. We discuss the impact of the
γ
p
→
K
Σ
channels in detail and investigate the influence of recent polarization data for
η
p
photoproduction.
Significance To our knowledge, no other nano-based vaccine delivery platform has directly assessed the effects of nanoparticle charge on pulmonary vaccination without affecting other physio/chemical ...particle characteristics and/or antigen loading. The Particle Replication in Non-Wetting Templates nanoparticle fabrication process is unique in that it allows for isolation of charge as the sole variable in these studies while maintaining all other physical and chemical parameters constant. We find that positively charged nanoparticles induce robust mucosal and systemic antibody responses following pulmonary administration, whereas negatively charged nanoparticles fail to do so. Therefore, our studies underscore the importance of considering nanoparticle charge as a critical design parameter when generating pulmonary-based vaccines and may have implications for particulate vaccination through other routes of administration.
Pulmonary immunization enhances local humoral and cell-mediated mucosal protection, which are critical for vaccination against lung-specific pathogens such as influenza or tuberculosis. A variety of nanoparticle (NP) formulations have been tested preclinically for pulmonary vaccine development, yet the role of NP surface charge on downstream immune responses remains poorly understood. We used the Particle Replication in Non-Wetting Templates (PRINT) process to synthesize hydrogel NPs that varied only in surface charge and otherwise maintained constant size, shape, and antigen loading. Pulmonary immunization with ovalbumin (OVA)-conjugated cationic NPs led to enhanced systemic and lung antibody titers compared with anionic NPs. Increased antibody production correlated with robust germinal center B-cell expansion and increased activated CD4 ⁺ T-cell populations in lung draining lymph nodes. Ex vivo treatment of dendritic cells (DCs) with OVA-conjugated cationic NPs induced robust antigen-specific T-cell proliferation with ∼100-fold more potency than soluble OVA alone. Enhanced T-cell expansion correlated with increased expression of surface MHCII, T-cell coactivating receptors, and key cytokines/chemokine expression by DCs treated with cationic NPs, which were not observed with anionic NPs or soluble OVA. Together, these studies highlight the importance of NP surface charge when designing pulmonary vaccines, and our findings support the notion that cationic NP platforms engender potent humoral and mucosal immune responses.
PDF
