Cobalt-Catalyzed Enantioselective Reductive Coupling of Imines and Internal Alkynes.

Chiral allyl amines are important structural components in natural products, pharmaceuticals, and chiral catalysts. Herein, we report a cobalt-catalyzed enantioselective reductive coupling of imines with internal alkynes to synthesize chiral allyl amines. The reaction is catalyzed by a cobalt complex derived from commercially available bisphosphine ligand utilizing zinc as the electron donor.

Tipping the balance between and ligand conformers in multinuclear ethylzinc cyclophosphazenates.

Hexaanionic cyclophosphazenate ligands [(RN)PN] provide versatile platforms for the assembly of multinuclear metal arrays due to their multiple coordination sites and highly flexible ligand core structure. This work investigates the impact of incrementally increasing the steric demand of the ligand periphery on the coordination behavior of ethylzinc arrays. It shows that the increased congestion around the ligand sites is alleviated by progressive condensation with the elimination of diethylzinc.

BBX22 enhances the accumulation of antioxidants to inhibit DNA damage and promotes DNA repair under high UV-B.

Under changing climatic conditions, plant exposure to high-intensity UV-B can be a potential threat to plant health and all plant-derived human requirements, including food. It's crucial to understand how plants respond to high UV-B radiation so that proper measures can be taken to enhance tolerance towards high UV-B stress. We found that BBX22, a B-box protein-coding gene, is strongly induced within one hour of exposure to high-intensity UV-B.

Distinguishing the Bimodal Interaction of a Squaraine Dye with a Protein by a Functional Group Photodeprotection Strategy.

In this study, we present a protecting group photocleavage method to investigate both covalent and noncovalent interactions between a squaraine dye (PSq) and Bovine Serum Albumin (BSA). This approach allows for the photoinduced activation and deactivation of PSq fluorescence, providing valuable insights into the dual-mode interaction of the dye with the protein.

Influence of Keto-Enol Tautomerism in Regulating CO Photoreduction Activity in Porous Organic Porphyrinic Photopolymers.

Photoassisted CO reduction employing a metal-free system is both challenging and fascinating. In our study, we present a structural engineering strategy to tune the potential energy barrier, which, in turn, affects the photoreduction ability. A series of porphyrin-based porous organic polymers () were hydrothermally synthesized and the influence of keto-enol tautomerization on the CO photoreduction potential has been rigorously investigated.

Ce[N(SiMe3)2]3(THF)3-Catalyzed Hydroboration of CO2, Esters and Epoxides with Pinacolborane: Selective Synthesis of Methanol in Multigram Scale.

In this work, we have reduced CO2 with HBpin to afford borylated methanol product selectively in ~99% yield using Ce[N(SiMe3)2]3(THF)3 as a catalyst. This led to multigram scale isolation of methanol obtained from CO2 reduction via the hydrolysis of borylated methanol, this establishes the potential of Ce[N(SiMe3)2]3(THF)3 as an efficient homogeneous catalyst for the bulk scale methanol synthesis. A practical application of this catalytic system was also shown by reducing CO2-containing motorbike exhaust efficiently and selectively.

Regioisomeric π-Extended Nanographene with Long-lived Phosphorescence Afterglow.

The cutouts of graphene sheets, particularly those with a nonplanar topology, present vast opportunities for advancement. Even a slight deviation from the planar structure can lead to intriguing (chiro)optical features for helically twisted nanographenes. In this context, we introduce two regioisomeric π-extended nanographenes that exhibit distinct excited-state characteristics.

Molecular mechanisms underlying allosteric behavior of Escherichia coli DgoR, a GntR/FadR family transcriptional regulator.

GntR/FadR family featuring an N-terminal winged helix-turn-helix DNA-binding domain and a C-terminal α-helical effector-binding and oligomerization domain constitutes one of the largest families of transcriptional regulators. Several GntR/FadR regulators govern the metabolism of sugar acids, carbon sources implicated in bacterial-host interactions. Although effectors are known for a few sugar acid regulators, the unavailability of relevant structures has left their allosteric mechanism unexplored.

Palladium-catalyzed distal γ- and ε-benzylation, allylation and allenylation of enones.

We report herein a palladium-catalyzed distal alkylation of silyldienol and silyltrienol ethers of enones through coupling with activated halides to achieve new - and -alkylated motifs. Additionally, by employing propargyl bromides, synthetically useful linear allenes along with functionalized enones have been synthesized. Low-catalyst loading, and late-stage transformations of pharmaceutically relevant molecules further showcase the importance of the present protocol.

Benchmark computations of nearly degenerate singlet and triplet states of N-heterocyclic chromophores. II. Density-based methods.

In this paper, we demonstrate the performance of several density-based methods in predicting the inversion of S1 and T1 states of a few N-heterocyclic triangulene based fused ring molecules (popularly known as INVEST molecules) with an eye to identify a well performing but cost-effective preliminary screening method. Both conventional linear-response time-dependent density functional theory (LR-TDDFT) and ΔSCF methods (namely maximum overlap method, square-gradient minimization method, and restricted open-shell Kohn-Sham) are considered for excited state computations using exchange-correlation (XC) functionals from different rungs of Jacob's ladder. A well-justified systematism is observed in the performance of the functionals when compared against fully internally contracted multireference configuration interaction singles and doubles and/or equation of motion coupled-cluster singles and doubles (EOM-CCSD), with the most important feature being the capture of spin-polarization in the presence of correlation.

Intramolecular Cascade Cyclization of Cyclobutanone: Asymmetric Construction of Cyclobutanone Fused Oxa-Spirocycles.

The successful implementation of a cascade reaction involving a cyclobutyl unit has posed a significant challenge in achieving ring-retentive functionalization because of the ring's sacrificial tendency. Herein, we have accomplished a cinchona-derived squaramide-catalyzed cascade reaction sequence, encompassing the desymmetrization of cyclobutanone, followed by an aldol reaction and, subsequently, a 1,4-addition step. This overall process offers a viable strategy to access architecturally fascinating oxa-spirocycles fused with cyclobutanone motifs in good yields with high optical purity.

Identification of ABHD6 as a lysophosphatidylserine lipase in the mammalian liver and kidneys.

Lysophosphatidylserine (lyso-PS) is a potent hormone-like signaling lysophospholipid, which regulates many facets of mammalian biology and dysregulation in its metabolism is associated with several human neurological and autoimmune diseases. Despite the physiological importance and causal relation with human pathophysiology, little is known about the metabolism of lyso-PS in tissues other than the nervous and immune systems. To address this problem, here, we attempted to identify one (or more) lipase(s) capable of degrading lyso-PS in different mammalian tissues.

Access to Bis-Silylene-Stabilized Group 13 Cations.

Herein, we report the isolation of pyridine moiety-functionalized SiNSi pincer-based bis-silylene ligand () and its reactivity toward various halide precursors (X = Br and I) of group 13 elements (M = Al, Ga, and In). This gave us straightforward access to the SiNSi pincer-coordinated group 13 cations (-). These complexes are duly characterized by single-crystal X-ray diffraction studies, multinuclear magnetic resonance spectroscopy (H, C, and Si), and high-resolution mass spectrometry techniques.

AAV-based gene delivery of antimicrobial peptides to combat drug-resistant pathogens.

Antimicrobial peptides (AMPs) have emerged as potential alternatives to conventional antibiotics due to their novelty and multiple mechanisms of action. Because they are peptides, AMPs are amenable to bioengineering and suitable for cloning and expression at large production scales. However, the efficient delivery of AMPs is an unaddressed issue, particularly due to their large size, possible toxicities, and the development of adverse immune responses.

Modulating the Optical Properties of Cationic Surfactant Cetylpyridinium Chloride and Hydrazine Mediated Copper Nanoclusters.

This study investigates the modulations in the optical properties of cationic surfactant cetylpyridinium chloride (CPC) and hydrazine-mediated copper nanoclusters (CuNCs). By employing a bottom-up approach, we demonstrate the formation of blue-emitting CuNCs facilitated by CPC and hydrazine, where hydrazine acts both as a reducing and stabilizing agent. The optical properties of the CuNCs were systematically tuned by varying the chain length of the diamine, resulting in emissions ranging from blue to yellow.

Assessing the impact of microplastics on gonadal health of the spadenose shark (Scoliodon laticaudus) on the west coast of India.

Pollutants such as microplastics (MPs) are detrimental to the health of humans, animals and reduce the quality of the environment. These particles can be ingested and accumulate in marine biota through the food chain leading to adverse effects on various physiological processes. Sharks, which typically occupy higher trophic levels in the marine food chain, may exhibit the highest accumulation of MPs.

Peptide toxins as tools in ion channel biology.

Animal venom contains ion channel-targeting peptide toxins that inflict paralysis or pain. The high specificity and potency of these toxins for their target ion channels provides enticing opportunities for their deployment as tools in channel biology. Mechanistic studies on toxin-mediated ion channel modulation have yielded landmark breakthroughs in our understanding of channel architectures and gating mechanisms.

Mitochondrial Sorting and Assembly Machinery: Chaperoning a Moonlighting Role?

The mitochondrial outer membrane (OMM) β-barrel proteins link the mitochondrion with the cytosol, endoplasmic reticulum, and other cellular membranes, establishing cellular homeostasis. Their active insertion and assembly in the outer mitochondrial membrane is achieved in an energy-independent yet highly effective manner by the Sorting and Assembly Machinery (SAM) of the OMM. The core SAM constituent is the 16-stranded transmembrane β-barrel Sam50.

Degradable Theranostic Polyurethane for Macrophage-Targeted Antileishmanial Drug Delivery.

The present investigation aims to develop a reactive oxygen species (ROS) and esterase-responsive biodegradable mannosylated polyurethane to effectively deliver the encapsulated antileishmanial drug amphotericin B (AmB) selectively to infected macrophage cells. Owing to suitable amphiphilic balance, the as-synthesized glycosylated polyurethane () with aryl boronic ester-based diol () moiety as ROS-trigger, water-soluble mannose pendants, and fluorescent 4,4-difluoro-4-bora-3a,4a-diaza--indacene (BODIPY) chain ends for bioimaging formed nanoaggregates in an aqueous medium as confirmed by H NMR spectroscopy, dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and critical aggregation concentration (CAC) measurements. Aided by two endogenous stimuli present in phagolysosome, ROS and esterase, AmB-encapsulated polymeric nanoaggregates as drug delivery vehicles achieved an efficient reduction of both and intracellular amastigote burden compared to the free AmB.

Splitting of the Girvin-MacDonald-Platzman Density Wave and the Nature of Chiral Gravitons in the Fractional Quantum Hall Effect.

A fundamental manifestation of the nontrivial correlations of an incompressible fractional quantum Hall (FQH) state is that an electron added to it disintegrates into more elementary particles, namely fractionally-charged composite fermions (CFs). We show here that the Girvin-MacDonald-Platzman (GMP) density-wave excitation of the ν=n/(2pn±1) FQH states also splits into more elementary single CF excitons. In particular, the GMP graviton, which refers to the recently observed spin-2 neutral excitation in the vanishing wave vector limit [Liang et al.

Effects of quenched disorder on the kinetics and pathways of phase transition in a soft colloidal system.

Although impurities are unavoidable in real-world and experimental systems, most numerical studies on nucleation focus on pure (impurity-free) systems. As a result, the role of impurities in phase transitions remains poorly understood, especially for systems with complex free energy landscapes featuring one or more intermediate metastable phases. In this study, we employed Monte Carlo simulations to investigate the effects of static impurities (quenched disorder) of varying length scales and surface morphologies on the crystal nucleation mechanism and kinetics in the Gaussian core model system-a representative model for soft colloidal systems.

TRIM32 regulates insulin sensitivity by controlling insulin receptor degradation in the liver.

Impaired insulin receptor signaling is strongly linked to obesity-related metabolic conditions like non-alcoholic fatty liver disease (NAFLD) and Type 2 diabetes (T2DM). However, the exact mechanisms behind impaired insulin receptor (INSR) signaling in obesity induced by a high-fat diet remain elusive. In this study, we identify an E3 ubiquitin ligase, tripartite motif-containing protein 32 (TRIM32), as a key regulator of hepatic insulin signaling that targets the insulin receptor (INSR) for ubiquitination and proteasomal degradation in high-fat diet (HFD) mice.

A Helically-twisted Stereodynamic Probe for Chiroptical Sensing of Chiral Amines through Point-to-helical Chirality Transmission.

Chiral amines and amino alcohols form an important category of molecules employed in the designing of new drugs and catalyst. Herein, we present a helically-twisted stereodynamic dialdehyde probe 1 for the determining of absolute configuration, and enantiomeric excess of chiral amine and amino alcohols. Probe 1 is based on the pyridine-2,6-dicarboxamide (PDC) core and undergoes rapid interconversion between the P- and M- conformers.

Synthesis of the conjugation ready tetrasaccharide repeating unit of the O-polysaccharide from Halomonas fontilapidosi KR26.

Synthesis of the tetrasaccharide repeating unit of the O-polysaccharide from Halomonas fontilapidosi KR26 was accomplished through a convergent [2 + 2]-block strategy using rationally protected monosaccharide synthons derived from commercially available sugars. The target tetrasaccharide was synthesized in the form of its 2-azidoethyl glycoside to ensure further conjugation with specific aglycons without hampering the reducing end stereochemistry. Use of only acyl/aryl protecting groups was targeted to keep the terminal azido-group intact for the utilization of "Click chemistry" for further conjugations.

NSD3 protein methylation and stabilization transforms human ES cells into variant state.

Cultured human embryonic stem cells (hESCs) can develop genetic anomalies that increase their susceptibility to transformation. In this study, we characterized a variant hESC (vhESC) line and investigated the molecular mechanisms leading to the drift towards a transformed state. Our findings revealed that vhESCs up-regulate EMT-specific markers, accelerate wound healing, exhibit compromised lineage differentiation, and retain pluripotency gene expression in teratomas.