Search

Halogen-containing molecules are ubiquitous in modern society and present unique chemical possibilities. As a whole, de novo fermentation and synthetic pathway construction for these molecules remain relatively underexplored and could unlock molecules with exciting new applications in industries ranging from textiles to agrochemicals to pharmaceuticals. Here, we report a mix-and-match co-culture platform to de novo generate a large array of halogenated tryptophan derivatives in Escherichia coli from glucose. First, we engineer E. coli to produce between 300 and 700 mg/L of six different halogenated tryptophan precursors. Second, we harness the native promiscuity of multiple downstream enzymes to access unexplored regions of metabolism. Finally, through modular co-culture fermentations, we demonstrate a plug-and-play bioproduction platform, culminating in the generation of 26 distinct halogenated molecules produced de novo including precursors to prodrugs 4-chloro- and 4-bromo-kynurenine and new-to-nature halogenated beta carbolines. De novo fermentation and synthetic pathway construction for halogen-containing molecules remain relatively underexplored. Here, the authors report a mix-and-match co-culture platform to de novo generate a large array of halogenated tryptophan derivatives in E. coli from glucose. [ABSTRACT FROM AUTHOR]

Regional climate models can be used to examine how past weather events might unfold under different climate conditions by simulating analogue versions of those events with modified thermodynamic conditions (i.e., warming signals). Here, we apply this approach by dynamically downscaling a 40-year sequence of past weather from 1980–2019 driven by atmospheric re-analysis, and then repeating this 40-year sequence a total of 8 times using a range of time-evolving thermodynamic warming signals that follow 4 80-year future warming trajectories from 2020–2099. Warming signals follow two emission scenarios (SSP585 and SSP245) and are derived from two groups of global climate models based on whether they exhibit relatively high or low climate sensitivity. The resulting dataset, which contains 25 hourly and over 200 3-hourly variables at 12 km spatial resolution, can be used to examine a plausible range of future climate conditions in direct reference to previously observed weather and enables a systematic exploration of the ways in which thermodynamic change influences the characteristics of historical extreme events. [ABSTRACT FROM AUTHOR]

Understanding the relationship between tropical cyclone (TC) precipitation and sea surface temperature (SST) is essential for both TC hazard forecasting and projecting how these hazards will change in the future due to climate change. This work untangles how global TC precipitation is impacted by present-day SST variability (known as apparent scaling) and by long-term changes in SST caused by climate change (known as climate scaling). A variety of datasets are used including precipitation and SST observations, realistic climate model simulations, and idealized climate model simulations. The apparent scaling rates depend on precipitation metric; examples shown here have ranges of 6.1 to 9.5% per K versus 5.9 to 9.8% per K for two different metrics. The climate scaling is estimated at about 5% per K, which is slightly less than the atmospheric moisture scaling based on thermodynamic principles of about 7% per K (i.e., the Clausius–Clapeyron scaling). The apparent scaling is greater than the climate scaling, which implies that the relationship between TC precipitation and present-day SST variability should not be used to project the long-term response of TC precipitation to climate change. [ABSTRACT FROM AUTHOR]

This correction notice is for an article titled "A modular and synthetic biosynthesis platform for de novo production of diverse halogenated tryptophan-derived molecules" published in Nature Communications. The correction addresses errors in figures 4D, 5A, 6A, 7, and 8, as well as Supplementary Figs. 18–22, 47, and 68–72. The incorrect connection of the formyl group in N-formyl-L-kynurenine and the derived compounds has been corrected in both the PDF and HTML versions of the article and the HTML version of the Supplementary Information. The authors have provided updated supplementary material. [Extracted from the article]

This study aimed to develop self-assembled gelatin-chitosan (Gel-CS) nanocapsules as a water-soluble delivery system for alcohol-soluble compounds. Eugenol (Eug) selected as the model molecule for its high solubility in alcohol and insolubility in water. The study also examined different reaction conditions and reagent loading ratios to optimize eugenol-embedded gelatin-chitosan nanocapsules (Eug-Gel-CS NPs) formation. The optimal loading ratio of Gel, CS, and Eug was 3:1:2, which yielded an average particle size of 229.09 nm and an encapsulation efficiency of 50.69%. The morphological characteristics of Eug-Gel-CS NPs were further demonstrated by transmission electron microscopy. The prepared Eug-Gel-CS NPs also exhibited potential controlled-release properties in aqueous phase with the in vitro release percentage of 69.47 ± 1.24% over 36 h. This nanocapsule system may provide a platform to expand the potential applications of Eug in food and nutrition. [ABSTRACT FROM AUTHOR]

This study examines how characteristics of tropical cyclones (TCs) that are explicitly resolved in a global atmospheric model with horizontal resolution of approximately 28 km are projected to change in a warmer climate using bias-corrected sea-surface temperatures (SSTs). The impact of mitigating from RCP8.5 to RCP4.5 is explicitly considered and is compared with uncertainties arising from SST projections. We find a reduction in overall global TC activity as climate warms. This reduction is somewhat less pronounced under RCP4.5 than under RCP8.5. By contrast, the frequency of very intense TCs is projected to increase dramatically in a warmer climate, with most of the increase concentrated in the NW Pacific basin. Extremes of storm related precipitation are also projected to become more common. Reduction in the frequency of extreme precipitation events is possible through mitigation from RCP8.5 to RCP4.5. In general more detailed basin-scale projections of future TC activity are subject to large uncertainties due to uncertainties in future SSTs. In most cases these uncertainties are larger than the effects of mitigating from RCP8.5 to RCP4.5. [ABSTRACT FROM AUTHOR]

The relationship between the two common measures of tropical cyclone intensity, the central pressure deficit and the peak near-surface wind speed, is a long-standing problem in tropical meteorology that has been approximated empirically yet lacks physical understanding. Here we provide theoretical grounding for this relationship. We first demonstrate that the central pressure deficit is highly predictable from the low-level wind field via gradient wind balance. We then show that this relationship reduces to a dependence on two velocity scales: the maximum azimuthal-mean azimuthal wind speed and half the product of the Coriolis parameter and outer storm size. This simple theory is found to hold across a hierarchy of models spanning reduced-complexity and Earth-like global simulations and observations. Thus, the central pressure deficit is an intensity measure that combines maximum wind speed, storm size, and background rotation rate. This work has significant implications for both fundamental understanding and risk analysis, including why the central pressure better explains historical economic damages than does maximum wind speed. [ABSTRACT FROM AUTHOR]

Large volunteer desktop platforms are now available for several kind of applications. More and more scientists consider this type of computing power as an alternative to the classical platforms such as dedicated clusters aggregated into Grids. This paper presents the work we did to run the first phase of the Help Cure Muscular Dystrophy project to run on World Community Grid. The project was launched on December 19, 2006, and took 26 weeks to complete. During this time frame, 123 GB of results were produced by volunteers who share their idle CPU time to compute a cross docking experiment over 168 proteins. We present performance evaluation of the overall execution and compare the World Community Grid volunteer Grid with a dedicated one. [ABSTRACT FROM AUTHOR]

We present a summary report of the CLIVAR Early Career Scientists Symposium, a three-day event associated with the CLIVAR Open Science Conference held in Qingdao, China during September 2016. The Symposium aimed to capture the ideas of early career researchers on pressing science priorities, imminent challenges, and emerging opportunities to help guide the future evolution of CLIVAR. We identified the need for improving process-based understanding and predictability of regional climate variability and change, moving toward seamless predictions, and improving and expanding global observations. We emphasize the need for increasingly open science, including universal access to data, code, and publications as well as opportunities for international cooperation and exchange. As the next generation of climate scientists, we are dedicated to overcome the challenges outlined in this summary and are looking forward to advancing CLIVAR's mission and activities. [ABSTRACT FROM AUTHOR]