Understanding the Factors Influencing the Ability of Calcium-Binding Peptides to Promote Calcium Absorption

The objective of this research was to determine the factors that influence the ability of calcium-binding peptides, obtained through in silico enzymatic hydrolysis of whey proteins, to promote calcium absorption. Isothermal titration calorimetry and density functional theory calculations revealed that all of the investigated peptides could spontaneously bind calcium through an entropy-driven endothermic binding reaction via their terminal and side-chain carboxyl groups at physiological pH. Among the investigated peptides, tripeptide EAC demonstrated the strongest ability to promote calcium absorption, with a calcium ion activity-based binding constant of 209 L/mol and a promotion factor of 2.57. The ability of calcium-binding peptides to promote calcium absorption was not correlated with their calcium-binding constants but rather with their chemical hardness and ionization potential. Machine learning modeling of all 8400 dipeptides and tripeptides indicated that those with higher log P values and aliphatic N/C-termini or aromatic C-termini were more likely to effectively promote calcium absorption. These findings provide valuable insights for the design of peptides to increase calcium bioavailability

Understanding the Factors Influencing the Ability of Calcium-Binding Peptides to Promote Calcium Absorption

The objective of this research was to determine the factors that influence the ability of calcium-binding peptides, obtained through in silico enzymatic hydrolysis of whey proteins, to promote calcium absorption. Isothermal titration calorimetry and density functional theory calculations revealed that all of the investigated peptides could spontaneously bind calcium through an entropy-driven endothermic binding reaction via their terminal and side-chain carboxyl groups at physiological pH. Among the investigated peptides, tripeptide EAC demonstrated the strongest ability to promote calcium absorption, with a calcium ion activity-based binding constant of 209 L/mol and a promotion factor of 2.57. The ability of calcium-binding peptides to promote calcium absorption was not correlated with their calcium-binding constants but rather with their chemical hardness and ionization potential. Machine learning modeling of all 8400 dipeptides and tripeptides indicated that those with higher log P values and aliphatic N/C-termini or aromatic C-termini were more likely to effectively promote calcium absorption. These findings provide valuable insights for the design of peptides to increase calcium bioavailability

Understanding the Factors Influencing the Ability of Calcium-Binding Peptides to Promote Calcium Absorption

The objective of this research was to determine the factors that influence the ability of calcium-binding peptides, obtained through in silico enzymatic hydrolysis of whey proteins, to promote calcium absorption. Isothermal titration calorimetry and density functional theory calculations revealed that all of the investigated peptides could spontaneously bind calcium through an entropy-driven endothermic binding reaction via their terminal and side-chain carboxyl groups at physiological pH. Among the investigated peptides, tripeptide EAC demonstrated the strongest ability to promote calcium absorption, with a calcium ion activity-based binding constant of 209 L/mol and a promotion factor of 2.57. The ability of calcium-binding peptides to promote calcium absorption was not correlated with their calcium-binding constants but rather with their chemical hardness and ionization potential. Machine learning modeling of all 8400 dipeptides and tripeptides indicated that those with higher log P values and aliphatic N/C-termini or aromatic C-termini were more likely to effectively promote calcium absorption. These findings provide valuable insights for the design of peptides to increase calcium bioavailability

Integration of the Ligase Chain Reaction with the CRISPR-Cas12a System for Homogeneous, Ultrasensitive, and Visual Detection of microRNA

The ligase chain reaction (LCR), as a classic nucleic acid amplification technique, is popular in the detection of DNA and RNA due to its simplicity, powerfulness, and high specificity. However, homogeneous and ultrasensitive LCR detection is still quite challenging. Herein, we integrate the LCR with a CRISPR-Cas12a system to greatly promote the application of the LCR in a homogeneous fashion. By employing microRNA as the model target, we design LCR probes with specific protospacer adjacent motif sequences and the guide RNA. Then, the LCR is initiated by target microRNA, and the LCR products specifically bind to the guide RNA to activate the Cas12a system, triggering secondary signal amplification to achieve ultrasensitive detection of microRNA without separation steps. Moreover, by virtue of a cationic conjugated polymer, microRNA can not only be visually detected by naked eyes but also be accurately quantified based on RGB ratio analysis of images with no need of sophisticated instruments. The method can quantify microRNA up to 4 orders of magnitude, and the determination limit is 0.4 aM, which is better than those of other reported studies using CRISPR-Cas12a and can be compared with that of the reverse-transcription polymerase chain reaction. This study demonstrates that the CRISPR-Cas12a system can greatly expand the application of the LCR for the homogeneous, ultrasensitive, and visual detection of microRNA, showing great potential in efficient nucleic acid detection and in vitro diagnosis

Homogeneous and Sensitive Detection of microRNA with Ligase Chain Reaction and Lambda Exonuclease-Assisted Cationic Conjugated Polymer Biosensing

A simple and homogeneous microRNA assay is developed by integration of ligase chain reaction (LCR) and lambda exonuclease-assisted cationic conjugated polymer (CCP) biosensing. LCR is utilized for exponential amplification of microRNA, and lambda exonuclease is introduced to degrade excess fluorescein-labeled probes in LCR for eliminating background signal. After addition of CCP, efficient fluorescence resonance energy transfer from CCP to fluorescein in LCR products occurs. The method is sensitive enough to detect 0.1 fM target microRNA and specific to discriminate one-base difference of microRNAs, which paves a new way for homogeneous microRNA detection and molecular diagnosis

Conjugated Polymers/DNA Hybrid Materials for Protein Inactivation

Chromophore-assisted light inactivation (CALI) is a powerful tool for analyzing protein functions due to the high degree of spatial and temporal resolution. In this work, we demonstrate a CALI approach based on conjugated polymers (CPs)/DNA hybrid material for protein inactivation. The target protein is conjugated with single-stranded DNA in advance. Single-stranded DNA can form CPs/DNA hybrid material with cationic CPs via electrostatic and hydrophobic interactions. Through the formation of CPs/DNA hybrid material, the target protein that is conjugated with DNA is brought into close proximity to CPs. Under irradiation, CPs harvest light and generate reactive oxygen species (ROS), resulting in the inactivation of the adjacent target protein. This approach can efficiently inactivate any target protein which is conjugated with DNA and has good specificity and universality, providing a new strategy for studies of protein function and adjustment of protein activity

Exposing Key Vibrational Contributions to Properties of Organic Molecular Solids with High Signal, Low Frequency Neutron Spectroscopy and Ab Initio Simulations

Stability and response of supramolecular forms is important to many areas in materials science, and contributions from vibrations can be crucial. We have collected the first spectra of organic molecular crystals and polymorphic cocrystals using the next-generation, high-signal VISION spectrometer in the far-infrared (FIR) and mid-infrared (MIR) range. Unambiguously different spectral signatures were found for carbamazepine and two polymorphs of the carbamazepine-saccharin cocrystal, including numerous modes undetectable with optical methods. For FIR-range frequencies, in addition to correct calculation of peak positions, accurate line-shape features were reproducible by simulation using ab initio vibrational calculations. High confidence spectral assignments and thermochemical information for this region are thus expected, and a benchmark for vibrational ab initio calculations is provided, creating a significant addition to methods used in investigation and design of organic materials

Tyramine-Invertase Bioconjugate-Amplified Personal Glucose Meter Signaling for Ultrasensitive Immunoassay

Highly sensitive and facile detection of low levels of protein markers is of great significance for the early diagnosis and efficacy monitoring of diseases. Herein, aided by an efficient tyramine-signal amplification (TSA) mechanism, we wish to report a simple but ultrasensitive immunoassay with signal readout on a portable personal glucose meter (PGM). In this study, the bioconjugates of tyramine and invertase (Tyr-inv), which act as the critical bridge to convert and amplify the protein concentration information into glucose, are prepared following a click chemistry reaction. Then, in the presence of a target protein, the sandwich immunoreaction between the immobilized capture antibody, the target protein, and the horseradish peroxidase (HRP)-conjugated detection antibody is specifically performed in a 96-well microplate. Subsequently, the specifically loaded HRP-conjugated detection antibodies will catalyze the amplified deposition of a large number of Tyr-inv molecules onto adjacent proteins through highly efficient TSA. Then, the deposited invertase, whose dosage can faithfully reflect the original concentration of the target protein, can efficiently convert sucrose to glucose. The amount of finally produced glucose is simply quantified by the PGM, realizing the highly sensitive detection of trace protein markers such as the carcinoembryonic antigen and alpha fetoprotein antigen at the fg/mL level. This method is simple, cost-effective, and ultrasensitive without the requirement of sophisticated instruments or specialized laboratory equipment, which may provide a universal and promising technology for highly sensitive immunoassay for in vitro diagnosis of diseases

Image_1_Antioxidant, aroma, and sensory characteristics of Maillard reaction products from Urechis unicinctus hydrolysates: development of food flavorings.JPEG

To develop food flavorings with a delicious taste and an anti-oxidation effect, in this study, the glucose Maillard reaction was used for hydrolysates of Urechis unicinctus. The various biological activities of Maillard reaction products (MRPs) and their antioxidant capacity were evaluated. The results showed that the unique fishy odor substances of seafood in MRPs were reduced, indicating that the Maillard reaction improved the flavor of the hydrolysate of Urechis unicinctus. Meanwhile, MRPs exhibited more competitive radical scavenging activities compared to the hydrolysate. Moreover, MRPs demonstrated a considerable potential to protect against 2,2′-Azobis (2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidative stress in a cell model in vitro and in a zebrafish model in vivo. Finally, a novel food flavoring was produced with MRPs as raw material, while the sensory qualities were deemed acceptable. In consequence, during industrial production, MRPs of Urechis unicinctus hydrolysate act as a high-quality raw material for functional flavorings and provide an effective way for the utilization of marine resources.</p