Interspecific Electron Transfer-Driven Oxytetracycline Degradation by Autotrophic Coculture of Sulfur-Oxidizing and Sulfate-Reducing Bacteria

Interspecific electron transport (IET) can promote the cometabolism of microorganisms, so it is of great significance in environmental remediation. Herein, a coculture of autotrophic sulfur-oxidizing bacteria (SOB) and heterotrophic sulfate-reducing bacteria (SRB) was constructed to biodegrade oxytetracycline (OTC) (upgraded to 120.9 ± 3.9 μg mg–1 protein d–1) under inorganic conditions, and the biodegradation was markedly improved (1.5 times) after loading biosynthetic FeS (bio-FeS). The increase of the NAD+/NADH ratio and ATPase activity indicated that more electrons generated by intracellular metabolism inside the SOB (lacking the OTC enzyme) outflowed extracellularly to the SRB via the IET chain in the coculture system. Linear sweep voltammetry (LSV) and I–t analysis indicated that bio-FeS on the SRB could enhance direct interspecific electron transport (DIET) mainly via c-Cyts, together with the mediated interspecific electron transport (MIET) via flavins, thus accelerating the OTC efflux. Community analysis demonstrated that the SRB introduction increased the abundance of genes related to environmental information, cell motility, membrane transport, and signal transduction in the coculture system. This discovery revealed the feasibility of antibiotic degradation using heterotrophic bacteria (such as SRB) under inorganic conditions and deepened the understanding of the antibiotic degradation in biogeochemical cycles involving carbon, nitrogen, and sulfur in natural ecosystems

Capturing Many-Body Interactions with Classical Dipole Induction Models

The nonadditive many-body interactions are significant for structural and thermodynamic properties of condensed phase systems. In this work we examined the many-body interaction energy of a large number of common organic/biochemical molecular clusters, which consist of 18 chemical species and cover nine common organic elements, using the Møller–Plesset perturbation theory to the second order (MP2) [Møller et al. Phys. Rev. 1934, 46, 618.]. We evaluated the capability of Thole-based dipole induction models to capture the many-body interaction energy. Three models were compared: the original model and parameters used by the AMOEBA force field, a variation of this original model where the damping parameters have been reoptimized to MP2 data, and a third model where the damping function form applied to the permanent electric field is modified. Overall, we find the simple classical atomic dipole models are able to capture the 3- and 4-body interaction energy across a wide variety of organic molecules in various intermolecular configurations. With modified Thole models, it is possible to further improve the agreement with MP2 results. These models were also tested on systems containing metal/halogen ions to examine the accuracy and transferability. This work suggests that the form of damping function applied to the permanent electrostatic field strongly affects the distance dependence of polarization energy at short intermolecular separations

Self-Assembly of Polyurethane Phosphate Ester with Phospholipid-Like Structures: Spherical, Worm-Like Micelles, Vesicles, and Large Compound Vesicles

Here, we report the preparation and self-assembly of amphiphilic polyurethane phosphate ester (PUP) polymers with phospholipid-like structures. The polymers, designed to have a hydrophilic phosphate head and two amphiphilic PPG-IPDI-MPEG (PU) tails were synthesized via coupling and phosphorylation reactions in sequence. These amphiphilic polymers could self-assemble into various interesting nanostructures in aqueous solution, such as spherical, worm-like micelles, vesicles, and large compound vesicles, depending on the hydrophobic chain length of PU tails and the initial polymer concentrations. It was found that the morphology transition is not only caused by the unique molecular structure of amphiphilic polyurethanes, but also influenced by the additional hydrophilic phosphate groups incorporated, which disturb the force balance governing the aggregation structures. This research supplies a new clue for the fabrication of well-defined nanostructures

A Highly Stereoselective Addition of Lithiated Ynamides to Ellman–Davis Chiral <i>N‑tert</i>-Butanesulfinyl Imines

A highly diastereoselective addition of lithiated ynamides to Ellman–Davis chiral imines is described. While additions of <i>N-</i>sulfonyl ynamides are highly stereoselective even without Lewis acids, the use of BF₃–OEt₂ completely reversed the stereoselectivity. In addition, oxazolidinone-substituted ynamides behaved differently and functioned better with BF₃–OEt₂, and the chirality of the oxazolidinone ring exerts no impact on the selectivity

A Highly Stereoselective Addition of Lithiated Ynamides to Ellman–Davis Chiral <i>N‑tert</i>-Butanesulfinyl Imines

A highly diastereoselective addition of lithiated ynamides to Ellman–Davis chiral imines is described. While additions of <i>N-</i>sulfonyl ynamides are highly stereoselective even without Lewis acids, the use of BF₃–OEt₂ completely reversed the stereoselectivity. In addition, oxazolidinone-substituted ynamides behaved differently and functioned better with BF₃–OEt₂, and the chirality of the oxazolidinone ring exerts no impact on the selectivity

A Highly Stereoselective Addition of Lithiated Ynamides to Ellman–Davis Chiral <i>N‑tert</i>-Butanesulfinyl Imines

A highly diastereoselective addition of lithiated ynamides to Ellman–Davis chiral imines is described. While additions of <i>N-</i>sulfonyl ynamides are highly stereoselective even without Lewis acids, the use of BF₃–OEt₂ completely reversed the stereoselectivity. In addition, oxazolidinone-substituted ynamides behaved differently and functioned better with BF₃–OEt₂, and the chirality of the oxazolidinone ring exerts no impact on the selectivity

A Highly Stereoselective Addition of Lithiated Ynamides to Ellman–Davis Chiral <i>N‑tert</i>-Butanesulfinyl Imines

A highly diastereoselective addition of lithiated ynamides to Ellman–Davis chiral imines is described. While additions of <i>N-</i>sulfonyl ynamides are highly stereoselective even without Lewis acids, the use of BF₃–OEt₂ completely reversed the stereoselectivity. In addition, oxazolidinone-substituted ynamides behaved differently and functioned better with BF₃–OEt₂, and the chirality of the oxazolidinone ring exerts no impact on the selectivity

Elucidating the Phosphate Binding Mode of Phosphate-Binding Protein: The Critical Effect of Buffer Solution

Phosphate is an essential component of cell functions, and the specific transport of phosphorus into a cell is mediated by phosphate-binding protein (PBP). The mechanism of PBP-phosphate recognition remains controversial: on the basis of similar binding affinities at acidic and basic pHs, it is believed that the hydrogen network in the binding site is flexible to adapt to different protonation states of phosphates. However, only hydrogen (1H) phosphate was observed in the sub-angstrom X-ray structures. To address this inconsistency, we performed molecular dynamics simulations using the AMOEBA polarizable force field. Structural and free energy data from simulations suggested that 1H phosphate was the preferred bound form at both pHs. The binding of dihydrogen (2H) phosphate disrupted the hydrogen-bond network in the PBP pocket, and the computed affinity was much weaker than that of 1H phosphate. Furthermore, we showed that the discrepancy in the studies described above is resolved if the interaction between phosphate and the buffer agent is taken into account. The calculated apparent binding affinities are in excellent agreement with experimental measurements. Our results suggest the high specificity of PBP for 1H phosphate and highlight the importance of the buffer solution for the binding of highly charged ligands

A Highly Stereoselective Addition of Lithiated Ynamides to Ellman–Davis Chiral <i>N‑tert</i>-Butanesulfinyl Imines

A highly diastereoselective addition of lithiated ynamides to Ellman–Davis chiral imines is described. While additions of <i>N-</i>sulfonyl ynamides are highly stereoselective even without Lewis acids, the use of BF₃–OEt₂ completely reversed the stereoselectivity. In addition, oxazolidinone-substituted ynamides behaved differently and functioned better with BF₃–OEt₂, and the chirality of the oxazolidinone ring exerts no impact on the selectivity

Table1_The spatial impact of digital economy on carbon emissions reduction: evidence from 215 cities in China.docx

Introduction: Within the global framework of carbon emissions constraints, the digital economy has become a new strategy for cities to achieve sustainable development. Scholarly literature exploring the spatial spillover and spatial mechanisms of the digital economy on carbon emissions is notably scarce.Methods: To estimate the spatial impact of digital economy on carbon emissions, this paper conducted spatial analysis with the spatial Dubin model and panel data of 215 cities in China from 2011 to 2019.Results: The results show that there is a growing regional agglomeration of the digital economy, whereas the spatial evolution of carbon emissions displays low liquidity and high stability. Second, the digital economy directly reduces urban carbon emissions, and this conclusion is supported through a series of robustness tests. However, there exist negative spatial spillover effects of digital economy on carbon emissions reduction in neighboring cities. Third, mechanism analysis reveals that the digital economy mainly affects urban carbon emissions through two paths: industrial structure upgrading and green technology innovation. Moreover, the influence of digital economy exhibits heterogeneity, with a more pronounced effect observed in the central cities and in large and medium-sized cities, as well as in cities with a high agglomeration of the new energy industry.Discussion: Our paper not only presents new documentary evidence for understanding the relationship between digitalization and decarbonization, but also provides specific references for policy making to accelerate low-carbon urban development.</p