The moderating effect of dietary fiber intake on the association between sleep pattern and liver fibrosis in metabolic dysfunction-associated steatotic liver disease: a study from NHANES.

Background: Insufficient nocturnal sleep was associated with a higher risk of fibrosis in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). Dietary fiber intake may improve the stimulate the secretion of sleep cytokines, inhibit the inflammatory pathway, contribute to regulating sleep disorders and alleviate liver fibrosis. The associations of dietary fiber intake, sleep patterns, with liver fibrosis remain unclear.

K-Specification with Flavone P0 Probe in a G-Quadruplex DNA.

G-quadruplex (G4) DNA is considered as a prospective therapeutic target due to its potential biological significance. To understand G4 biological roles and function, a G4-specific fluorescent probe is necessary. However, it is difficult for versatile G4 to precisely recognize without perturbing their folding dynamics.

Efficient Silver(I)-Containing I-Motif DNA Hybrid Catalyst for Enantioselective Diels-Alder Reactions.

The inherent chiral structures of DNA serve as attractive scaffolds to construct DNA hybrid catalysts for valuable enantioselective transformations. Duplex and G-quadruplex DNA-based enantioselective catalysis has made great progress, yet novel design strategies of DNA hybrid catalysts are highly demanding and atomistic analysis of active centers is still challenging. DNA i-motif structures could be finely tuned by different cytosine-cytosine base pairs, providing a new platform to design DNA catalysts.

Dopamine oxidation promoted by human telomeric DNA models in the presence of a Cu(II) terpyridine chelate.

We found that under oxidative stress conditions, the coexistence of human telomeric DNA (HT-DNA) and a copper-terpyridine metallodrug can accelerate dopamine oxidation. The unwinding of HT-DNA from a duplex to cytosine-rich (C-rich) and guanine-rich (G-rich) single strands promotes dopamine oxidation in a general order of C-rich > G-rich > duplex. Along with dopamine oxidation, HT-DNA also undergoes severe damage.

Cationic Porphyrin-Mediated G-Quadruplex DNA Oxidative Damage: Regulated by the Initial Interplay between DNA and TMPyP4.

G-quadruplex (G4) ligand-induced DNA damage has been involved in many physiological functions of cells. Herein, cationic porphyrin (TMPyP4)-mediated DNA oxidation damage was investigated aiming at mitochondrial G4 DNA (mt9438) and its structural analogue of the thrombin-binding aptamer (TBA). TMPyP4 is found to stabilize TBA G4 but destabilize mt9438.

Controllable stereoinversion in DNA-catalyzed olefin cyclopropanation cofactor modification.

The assembly of DNA with metal-complex cofactors can form promising biocatalysts for asymmetric reactions, although catalytic performance is typically limited by low enantioselectivities and stereo-control remains a challenge. Here, we engineer G-quadruplex-based DNA biocatalysts for an asymmetric cyclopropanation reaction, achieving enantiomeric excess (ee) values of up to +91% with controllable stereoinversion, where the enantioselectivity switches to -72% ee through modification of the Fe-porphyrin cofactor. Complementary circular dichroism, nuclear magnetic resonance, and fluorescence titration experiments show that the porphyrin ligand of the cofactor participates in the regulation of the catalytic enantioselectivity a synergetic effect with DNA residues at the active site.

The noncovalent dimerization of a G-quadruplex/hemin DNAzyme improves its biocatalytic properties.

While many protein enzymes exert their functions through multimerization, which improves both selectivity and activity, this has not yet been demonstrated for other naturally occurring catalysts. Here, we report a multimerization effect applied to catalytic DNAs (or DNAzymes) and demonstrate that the enzymatic efficiency of G-quadruplexes (GQs) in interaction with the hemin cofactor is remarkably enhanced by homodimerization. The resulting non-covalent dimeric GQ-DNAzyme system provides hemin with a structurally defined active site in which both the cofactor (hemin) and the oxidant (HO) are activated.

Highly Selective Detection of K Based on a Dimerized G-Quadruplex DNAzyme.

Potassium ion (K) plays a crucial role in biological systems, such as maintaining cellular processes and causing diseases. However, specifically, the detection of K is extremely challenging because of the coexistence of the chemically similar ion of Na under physiological conditions. In this work, a K specific biosensor is constructed on the basis of a dimerized G-quadruplex (GQ) DNA, which is promoted by K, and the enzymatic activity of the resulting DNAzyme depends on the concentration of the K.

A Causal Role of the Cerebellum in Auditory Feedback Control of Vocal Production.

Accumulating evidence demonstrates that the cerebellum is involved in a variety of cognitive functions. Recently, impaired auditory-motor integration for vocal control has been identified in patients with cerebellar degeneration, characterized by abnormally enhanced vocal compensations for pitch perturbations. However, the causal relationship between the cerebellum and auditory feedback during vocal production remains unclear.

Towards Security Joint Trust and Game Theory for Maximizing Utility: Challenges and Countermeasures.

The widespread application of networks is providing a better platform for the development of society and technology. With the expansion of the scope of network applications, many issues need to be solved. Among them, the maximization of utility and the improvement of security have attracted much attention.

Highly Efficient Cyclic Dinucleotide Based Artificial Metalloribozymes for Enantioselective Friedel-Crafts Reactions in Water.

The diverse secondary structures of nucleic acids are emerging as attractive chiral scaffolds to construct artificial metalloenzymes (ArMs) for enantioselective catalysis. DNA-based ArMs containing duplex and G-quadruplex scaffolds have been widely investigated, yet RNA-based ArMs are scarce. Here we report that a cyclic dinucleotide of c-di-AMP and Cu ions assemble into an artificial metalloribozyme (c-di-AMP⋅Cu ) that enables catalysis of enantioselective Friedel-Crafts reactions in aqueous media with high reactivity and excellent enantioselectivity of up to 97 % ee.

Stereostructural Elucidation of Glucose Phosphorylation by Raman Optical Activity.

Phosphorylation of glucose is the prime step in sugar metabolism and energy storage. Two key glucose phosphates are involved, that is, glucose 6-phosphate (G6P) and α-glucose 1-phosphate (αG1P). The chiral conformation of glucose, G6P, and αG1P plays an essential role in enzyme-mediated conversions.

Loop permutation affects the topology and stability of G-quadruplexes.

G-quadruplexes are unusual DNA and RNA secondary structures ubiquitous in a variety of organisms including vertebrates, plants, viruses and bacteria. The folding topology and stability of intramolecular G-quadruplexes are determined to a large extent by their loops. Loop permutation is defined as swapping two or three of these regions so that intramolecular G-quadruplexes only differ in the sequential order of their loops.

Fluorescence Spectroscopic Insight into the Supramolecular Interactions in DNA-Based Enantioselective Sulfoxidation.

Interactions of copper(II)-bipyridine cofactors and thioanisole substrate with human telomeric G-quadruplex DNA were studied by UV/Vis absorption, circular dichroism, and fluorescence quenching titration. Three copper(II)-bipyridine complexes are equivalently anchored to the G-quadruplex scaffold at all five fluorescently labeled sites. Thioanisole interacts with the DNA architecture at both the second loop and 3' terminus in the absence or presence of copper(II)-bipyridine complexes.

Probing the interaction of copper cofactor and azachalcone substrate with G-quadruplex of DNA based Diels-Alderase by site-specific fluorescence quenching titration.

DNAzymes have been widely used in biosensors, asymmetric synthesis and pharmaceuticals. Typically, metal cofactor and substrate interact with DNA by supramolecular interactions in DNAzyme based asymmetric catalysis. However, binding positions of cofactor and substrate with DNA scaffold are not well understood, which is an obstacle to reveal the assembly and catalysis mechanisms of DNAzyme.

A Short-Wavelength Raman Optical Activity Spectrometer with Laser Source at 457 nm for the Characterization of Chiral Molecules.

Developing a high-sensitivity Raman optical activity (ROA) spectrometer has been regarded as one of the great challenges in chiral science and technology. Herein, we report our recent progress on the development of a short-wavelength ROA (sw-ROA) spectrometer with the excitation line at 457 nm, which shows obviously improved signal-to-noise (S/N) ratio compared with the currently available 532 nm ROA spectrometer. This could be ascribed to the fifth-power of frequency dependence for ROA intensity together with the potential advantage of avoiding fluorescence for most molecules.

Relations between the loop transposition of DNA G-quadruplex and the catalytic function of DNAzyme.

The structures of DNA G-quadruplexes are essential for their functions in vivo and in vitro. Our present study revealed that sequential order of the three G-quadruplex loops, that is, loop transposition, could be a critical factor to determinate the G-quadruplex conformation and consequently improved the catalytic function of G-quadruplex based DNAzyme. In the presence of 100mM K, loop transposition induced one of the G-quadruplex isomers which shared identical loops but differed in the sequential order of loops into a hybrid topology while the others into predominately parallel topologies.

Enantioselective sulfoxidation reaction catalyzed by a G-quadruplex DNA metalloenzyme.

Enantioselective sulfoxidation reaction is achieved for the first time by a DNA metalloenzyme assembled with the human telomeric G-quadruplex DNA and Cu(ii)-4,4'-bimethyl-2,2'-bipyridine complex, and the mixed G-quadruplex architectures are responsible for the catalytic enantioselectivity and activity.

Terpyridine-Cu(ii) targeting human telomeric DNA to produce highly stereospecific G-quadruplex DNA metalloenzyme.

The cofactors commonly involved in natural enzymes have provided the inspiration for numerous advances in the creation of artificial metalloenzymes. Nevertheless, to design an appropriate cofactor for a given biomolecular scaffold or remains a challenge in developing efficient catalysts in biochemistry. Herein, we extend the idea of G-quadruplex-targeting anticancer drug design to construct a G-quadruplex DNA metalloenzyme.

Higher-order human telomeric G-quadruplex DNA metalloenzyme catalyzed Diels-Alder reaction: an unexpected inversion of enantioselectivity modulated by K(+) and NH4(+) ions.

We report that K(+) and NH4(+) present different allosteric activation for higher-order human telomeric G-quadruplex DNA metalloenzyme. The obtained major endo products of Diels-Alder reaction can be switched from one preferred configuration in K(+) media (up to 92% ee) to its mirror configuration in NH4(+) media (up to -90% ee).

Higher-order human telomeric G-quadruplex DNA metalloenzymes enhance enantioselectivity in the Diels-Alder reaction.

Short human telomeric (HT) DNA sequences form single G-quadruplex (G4 ) units and exhibit structure-based stereocontrol for a series of reactions. However, for more biologically relevant higher-order HT G4 -DNAs (beyond a single G4 unit), the catalytic performances are unknown. Here, we found that higher-order HT G4 -DNA copper metalloenzymes (two or three G4 units) afford remarkably higher enantioselectivity (>90 % ee) and a five- to sixfold rate increase, compared to a single G4 unit, for the Diels-Alder reaction.

Na+/K+ switch of enantioselectivity in G-quadruplex DNA-based catalysis.

Here we found that the enantioselectivity of G-quadruplex DNA-based Diels-Alder reaction can be switched by just changing Na(+) to K(+), which is ascribed to the structural transformation of the G-quadruplex from antiparallel to hybrid-type. By tuning the ratio of Na(+)/K(+), the enantioselectivity of the Diels-Alder reaction could be switchable and shows much more sensitive to K(+) than to Na(+).

Promoting antitumor activities of hydroxycamptothecin by encapsulation into acid-labile nanoparticles using electrospraying.

Purpose: Acid-labile nanoparticles are proposed to enhance the tumor targeting and anti-tumor therapy of hydroxycamptothecin (HCPT) in response to the acidic microenvironment within cells and tumor tissues.

Methods: HCPT was entrapped into matrix polymers containing acid-labile segments and galactose moieties (PGBELA) through an electrospraying technique. The antitumor activities of HCPT-loaded nanoparticles were evaluated both on HepG2 cells and after intravenous injection into H22 tumor-bearing mice.