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Environmental Pollution (Barking, Essex... Oct 2023Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food...
Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food proteins are still unknown. In this study, the interactions between pepsin and polystyrene (PS) MPs were evaluated by investigating enzyme activity and conformation in a simulated human gastric environment in the presence or absence of PS MPs. The impact on food digestion was also assessed by monitoring the kinetics of protein hydrolysis through static in vitro gastric digestion of cow's milk contaminated with PS. The binding of pepsin to PS showed that the surface chemistry of MPs dictates binding affinity. The key contributor to pepsin adsorption seems to be π-π interactions between the aromatic residues and the PS phenyl rings. During quick exposure (10 min) of pepsin to increasing concentrations (222, 2219, 22188 particles/mL) of 10 μm PS (PS10) and 100 μm PS (PS100), total enzymatic activities were not affected remarkably. However, upon prolonged exposure at 1 and 2 h, preferential binding of pepsin to the small, low zeta-potential PS caused structural changes in the protein which led to a significant reduction of its activity. Digestion of cow's milk mixed with PS10 resulted in transient accumulation of larger peptides (10-35 kDa) and reduced bioavailability of short peptides (2-9 kDa) in the gastric phase. This, however, was only observed at extremely high PS10 concentration (0.3 mg/mL or 5.46E+05 particles/mL). The digestion of milk peptides, bound preferentially over pepsin within the hard corona on the PS10 surface, was delayed up to 15 min in comparison to bulk protein digestion. Intact caseins, otherwise rapidly digested, remained bound to PS10 in the hard corona for up to 15 min. This work presents valuable insights regarding the interaction of MPs, food proteins, and pepsin, and their dynamics during gastric digestion.
Topics: Humans; Milk Proteins; Pepsin A; Microplastics; Polystyrenes; Plastics; Peptides; Caseins; Allergens; Digestion
PubMed: 37516294
DOI: 10.1016/j.envpol.2023.122282 -
International Journal of Biological... Sep 2023Fish skin gelatin is an important functional product used in food, medicine and other industries. However, the structure and function of gelatins extracted with...
Fish skin gelatin is an important functional product used in food, medicine and other industries. However, the structure and function of gelatins extracted with different methods differ significantly, thus limiting its production and application. This study used dry-salting, wet-salting, pepsin, acid and heat methods to extract gelatins from the skins of tilapia, grass carp and sea perch. Then, their structural characteristics (micro- and ultra-structure, amyloid-like fibril, etc.) and functional properties (viscosity, emulsifying performance, antioxidant abilities, etc.) were analyzed, and interaction between gelatin components were also explored. According to the results, the gelatins extracted with dry-salting and wet-salting methods had better reticular structure, larger fiber length/height, and higher viscosity properties, emulsifying and antioxidant capacity. The gelatin extracted by applying heat has the highest gel strength, and the gelatin extracted using pepsin had better thermal stability, water absorption capacity, and fat absorption capacity. Further analysis of component interaction showed that 11 types of collagens detected in the gelatins might promote the conversion of collagen to gelatin through self-assembly ability. The co-assembly of different types of collagens enhanced the properties of gelatin. Decorin had a positive effect on gelatin network structure, but Metallopeptidase inhibited the formation of network structure. Different methods can produce personalized gelatin products according to specific needs. The mining of component interaction would reveal the mechanism of gelatin formation and promote the development of gelatin synthetic biology.
Topics: Animals; Gelatin; Antioxidants; Pepsin A; Chemical Phenomena; Collagen
PubMed: 37479198
DOI: 10.1016/j.ijbiomac.2023.125813 -
Journal of Pharmaceutical Sciences Dec 2023Commonly, most oral non-steroidal anti-inflammatory drugs (NSAIDs) have known gastric adverse reactions due to their long-term and high dose administration. In this...
Commonly, most oral non-steroidal anti-inflammatory drugs (NSAIDs) have known gastric adverse reactions due to their long-term and high dose administration. In this study, a novel liquid sustained-release system based on multiple-unit in situ hydrogel beads was designed to address this issue. The system is composed of sodium alginate (SA), gellan gum (GG), zinc oxide (ZnO), and magnesium oxide (MgO). Furthermore, indobufen was loaded into the system to evaluate its gastric mucosal protection effect. This effect can be attributed to the topical antacid, pepsin inhibition, and sustained drug release properties of the system. It was proven that the stored solid gel system could undergo a "solid to liquid" transition after shaking. Once swallowed, the liquid gel could disperse well in the stomach as hydrogel beads. Then, the "liquid to solid" gelation occurred from the exterior to interior of each multiple-unit gel bead, triggered by the release of Zn and Mg from neutralization reactions. The formed gel demonstrated mild antacid effect that lasted for 3 hours and 66.3% pepsin inhibition in vivo. Moreover, the rats treated with the indobufen gel system showed a drug plasma concentration versus time curve with less fluctuation compared to the rats treated with the marketed preparation (YinDuo®) group. The gel system also exhibited an extended T (6.50 hours) and reduced C (52.87 μg/mL). Additionally, the gastric mucosal protection of the gel system was verified using three types of peptic gastric ulcer models. These findings suggested that this multiple-unit in situ gel could be a potential oral liquid sustained release delivery system for NSAIDs.
Topics: Rats; Animals; Hydrogels; Delayed-Action Preparations; Antacids; Pepsin A; Anti-Inflammatory Agents, Non-Steroidal
PubMed: 37473917
DOI: 10.1016/j.xphs.2023.07.016 -
Experimental Eye Research Sep 2023The corneal stroma is primarily composed of collagen fibrils, proteoglycans, and glycosaminoglycans (GAGs). It is known that corneal crosslinking (CXL) treatment...
The corneal stroma is primarily composed of collagen fibrils, proteoglycans, and glycosaminoglycans (GAGs). It is known that corneal crosslinking (CXL) treatment improves mechanical properties of the cornea. However, the influence of stromal composition on the strengthening effect of CXL procedure has not been thoroughly investigated. The primary objective of the present research was to characterize the effect of keratan sulfate (KS) GAGs on the efficacy of CXL therapy. To this end, the CXL method was used to crosslink porcine corneal samples from which KS GAGs were enzymatically removed by keratanase II enzyme. Alcian blue staining was done to confirm the successful digestion of GAGs and uniaxial tensile experiments were performed for characterizing corneal mechanical properties. The influence of GAG removal and CXL treatment on resistance of corneal samples against enzymatic pepsin degradation was also quantified. It was found that removal of KS GAGs significantly softened corneal tensile properties (P < 0.05). Moreover, the CXL therapy significantly increased the tensile stiffness of GAG-depleted strips (P < 0.05). GAG-depleted corneal buttons were dissolved in the pepsin digestion solution significantly faster than control samples (P < 0.05). The CXL treatment significantly increased the time needed for complete pepsin digestion of GAG-depleted disks (P < 0.05). Based on these observations, we concluded that KS GAGs play a significant role in defining tensile properties and structural integrity of porcine cornea. Furthermore, the stiffening influence of the CXL treatment does not significantly depend on the density of corneal KS GAGs. The findings of the present study provided new information on the relation between corneal composition and CXL procedure mechanical effects.
Topics: Swine; Animals; Glycosaminoglycans; Keratan Sulfate; Pepsin A; Collagen; Cornea; Corneal Stroma; Cross-Linking Reagents; Photosensitizing Agents; Riboflavin; Ultraviolet Rays; Keratoconus
PubMed: 37454921
DOI: 10.1016/j.exer.2023.109570 -
Biomedical Engineering Online Jul 2023Tube misplacement into the tracheobronchial tract is associated with pneumothorax in 0.5% of cases. NGT verification only detects the position of the tube at the end of...
Preclinical trial of the effectiveness of a safety nasogastric tube to detect the tube position based on tidal volume and pepsin assay results in the gastrointestinal tract of Macaca fascicularis.
BACKGROUND
Tube misplacement into the tracheobronchial tract is associated with pneumothorax in 0.5% of cases. NGT verification only detects the position of the tube at the end of the procedure. Therefore, a safe nasogastric tube (SNGT) was created to detect the NGT position in real time in a simple and inexpensive way. This study aimed to prove the effectiveness of the SNGT prototype in Macaca fascicularis.
RESULT
An SNGT producing 50% of the TV had 100% sensitivity and specificity in detecting the position of the tube at 100% of the TV, with a sensitivity of 100% and a specificity of 87.5%. There was a significant difference between the movement of the SNGT 50% TV and SNGT 100% TV airbags (p ≤ 0.05). However, there was no significant difference between the accuracy of placement of the 50% TV SNGT, 100% TV SNGT, and conventional NGT (p > 0.05). The pepsin enzyme had better sensitivity (100%) than pH paper (91.66%) in detecting the end-of-procedure tube position. This research has the potential to advance into human clinical trials.
CONCLUSION
SNGTs are highly effective in detecting the NGT position inside the respiratory and digestive tracts to prevent misplacement.
Topics: Animals; Gastrointestinal Tract; Intubation, Gastrointestinal; Macaca fascicularis; Pepsin A; Tidal Volume; Clinical Trials as Topic
PubMed: 37443035
DOI: 10.1186/s12938-023-01128-5 -
PloS One 2023Today, breast cancer and infectious diseases are very worrying that led to a widespread effort by researchers to discover natural remedies with no side effects to fight...
Today, breast cancer and infectious diseases are very worrying that led to a widespread effort by researchers to discover natural remedies with no side effects to fight them. In the present study, we isolated camel milk protein fractions, casein and whey proteins, and hydrolyzed them using pepsin, trypsin, and both enzymes. Screening of peptides with anti-breast cancer and antibacterial activity against pathogens was performed. Peptides derived from whey protein fraction with the use of both enzymes showed very good activity against MCF-7 breast cancer with cell viability of 7.13%. The separate use of trypsin and pepsin to digest whey protein fraction yielded peptides with high antibacterial activity against S. aureus (inhibition zone of 4.17 ± 0.30 and 4.23 ± 0.32 cm, respectively) and E. coli (inhibition zone of 4.03 ± 0.15 and 4.03 ± 0.05 cm, respectively). Notably, in order to identify the effective peptides in camel milk, its protein sequences were retrieved and enzymatically digested in silico. Peptides that showed both anticancer and antibacterial properties and the highest stability in intestinal conditions were selected for the next step. Molecular interaction analysis was performed on specific receptors associated with breast cancer and/or antibacterial activity using molecular docking. The results showed that P3 (WNHIKRYF) and P5 (WSVGH) peptides had low binding energy and inhibition constant so that they specifically occupied active sites of protein targets. Our results introduced two peptide-drug candidates and new natural food additive that can be delivered to further animal and clinical trials.
Topics: Animals; Camelus; Protein Hydrolysates; Escherichia coli; Molecular Docking Simulation; Pepsin A; Staphylococcus aureus; Trypsin; Whey Proteins; Neoplasms; Peptides; Anti-Bacterial Agents
PubMed: 37437001
DOI: 10.1371/journal.pone.0288260 -
Food & Function Jul 2023The effect of Ca on pepsin-induced hydrolysis of κ-casein and subsequent coagulation of casein micelles was studied in a micellar casein (MC) solution at pH ≈ 6.0 at...
The effect of Ca on pepsin-induced hydrolysis of κ-casein and subsequent coagulation of casein micelles was studied in a micellar casein (MC) solution at pH ≈ 6.0 at 37 °C without stirring. An NaCl-supplemented MC solution was used as a positive control to assess the effect of increased ionic strength after CaCl addition. Quantitative determination of the released -κ-casein during the reaction using reverse-phase high-performance liquid chromatography showed that specific hydrolysis of κ-casein by pepsin was little affected by the addition of either CaCl or NaCl. However, rheological properties and microstructures of curds induced by pepsin hydrolysis depended markedly on the addition of salts. Addition of CaCl up to 17.5 mM facilitated coagulation, with decreases in coagulation time and critical hydrolysis degree, and increases in firming rate and maximum storage modulus ('); further addition of CaCl (22.5 mM) resulted in a lower '. Increased ionic strength to 52.5 mM by adding NaCl retarded the coagulation and resulted in a looser curd structure. In a human gastric simulator, MC, without the addition of CaCl, did not coagulate until the pH decreased to ≈5.0 after ≈50 min of digestion. Addition of CaCl facilitated coagulation of casein micelles and resulted in more cohesive curds with dense structures during digestion, which slowed the emptying rate of caseins. At the same CaCl concentration, a sample with higher ionic strength coagulated more slowly. This study provides further understanding on the effect of divalent (Ca) ions and ionic strength on the coagulation of casein micelles and the digestion behavior of milk.
Topics: Humans; Animals; Caseins; Micelles; Pepsin A; Sodium Chloride; Calcium Chloride; Milk; Digestion; Hydrogen-Ion Concentration
PubMed: 37435798
DOI: 10.1039/d3fo01126g -
Food Chemistry Dec 2023The stability behaviors of oxidized SPI emulsions under in vitro gastric conditions and the effects of pepsin diffusion on the proteolysis of emulsions were investigated...
The stability behaviors of oxidized SPI emulsions under in vitro gastric conditions and the effects of pepsin diffusion on the proteolysis of emulsions were investigated using a static gastric model and the fluorescence recovery after photobleaching method. Results showed that protein oxidation increased the particle size of droplets and decreased the viscoelasticity of the interfacial layer. Compared to the control group (82.81 m/s), the pepsin diffusivity decreased to 68.52 m/s (7LA + LOX group) due to the space hindrance of oil droplets. After gastric digestion, protein hydrolysates were re-absorbed on the oil-water interface and formed a thick layer, thereby decreasing the size of oil droplets and reducing the contents of free amino acids in gastric digesta. The protein oxidation may affect the adsorption of interfacial proteins and alter the distribution of droplets, decreasing pepsin diffusion and ultimately impairing the emulsion gastric digestion. And this should be considered in the design of emulsion as the controllable delivery system.
Topics: Pepsin A; Emulsions; Stomach; Proteins; Particle Size; Digestion
PubMed: 37429241
DOI: 10.1016/j.foodchem.2023.136791 -
International Journal of Antimicrobial... Sep 2023We recently designed a series of cationic deoxythymidine-based amphiphiles that mimic the cationic amphipathic structure of antimicrobial peptides (AMPs). Among these...
OBJECTIVES
We recently designed a series of cationic deoxythymidine-based amphiphiles that mimic the cationic amphipathic structure of antimicrobial peptides (AMPs). Among these amphiphiles, ADG-2e and ADL-3e displayed the highest selectivity against bacterial cells. In this study, ADG-2e and ADL-3e were evaluated for their potential as novel classes of antimicrobial, antibiofilm, and anti-inflammatory agents.
METHODS
Minimum inhibitory concentrations of ADG-2e and ADL-3e against bacteria were determined using the broth microdilution method. Proteolytic resistance against pepsin, trypsin, α-chymotrypsin, and proteinase K was determined by radial diffusion and HPLC analysis. Biofilm activity was investigated using the broth microdilution and confocal microscopy. The antimicrobial mechanism was investigated by membrane depolarization, cell membrane integrity analysis, scanning electron microscopy (SEM), genomic DNA influence and genomic DNA binding assay. Synergistic activity was evaluated using checkerboard method. Anti-inflammatory activity was investigated using ELISA and RT-PCR.
RESULTS
ADG-2e and ADL-3e showed good resistance to physiological salts and human serum, and a low incidence of drug resistance. Moreover, they exhibit proteolytic resistance against pepsin, trypsin, α-chymotrypsin, and proteinase K. ADG-2e and ADL-3e were found to kill bacteria by an intracellular target mechanism and bacterial cell membrane-disrupting mechanism, respectively. Furthermore, ADG-2e and ADL-3e showed effective synergistic effects when combined with several conventional antibiotics against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa (MDRPA). Importantly, ADG-2e and ADL-3e not only suppressed MDRPA biofilm formation but also effectively eradicated mature MDRPA biofilms. Furthermore, ADG-2e and ADL-3e drastically decreased tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) gene expression and protein secretion in lipopolysaccharide (LPS)-stimulated macrophages, implying potent anti-inflammatory activity in LPS-induced inflammation.
CONCLUSION
Our findings suggest that ADG-2e and ADL-3e could be further developed as novel antimicrobial, antibiofilm, and anti-inflammatory agents to combat bacterial infections.
Topics: Humans; Antimicrobial Cationic Peptides; Methicillin-Resistant Staphylococcus aureus; Lipopolysaccharides; Endopeptidase K; Pepsin A; Trypsin; Anti-Infective Agents; Anti-Bacterial Agents; Anti-Inflammatory Agents; Bacteria; Biofilms; Thymidine; Microbial Sensitivity Tests
PubMed: 37419291
DOI: 10.1016/j.ijantimicag.2023.106909 -
Journal of Agricultural and Food... Jul 2023The potential of probiotics to benefit digestion has been widely reported, while its utilization in high-risk patients and potential adverse reactions have focused...
The potential of probiotics to benefit digestion has been widely reported, while its utilization in high-risk patients and potential adverse reactions have focused interest on postbiotics. A variable data-independent acquisition (vDIA)-based spatial-omics strategy integrated with unsupervised variational autoencoders was applied to profile the functional mechanism underlying the action of -derived postbiotic supplementation in goat milk digestion in an infant digestive system, from a metabolomics-peptidomics-proteomics perspective. Amide and olefin derivatives were proved to elevate the activities of pepsin and trypsin through hydrogen bonding and hydrophobic forces based on allosteric effects, and recognition of nine endopeptidases and their cleavage to serine, proline, and aspartate were introduced by postbiotics, thereby promoting the generation of hydrophilic peptides and elevating the bioaccessibility of goat milk protein. The peptides originating from αs1-casein, β-casein, β-lactoglobulin, Ig-like domain-containing protein, κ-casein, and serum amyloid A protein, with multiple bioactivities including angiotensin I-converting enzyme (ACE)-inhibitory, osteoanabolic, dipeptidyl peptidase IV (DPP-IV) inhibitory, antimicrobial, bradykinin-potentiating, antioxidant, and anti-inflammatory activities, were significantly increased in the postbiotic supplementation group, which was also considered to potentially prevent necrotizing enterocolitis through inhibiting the multiplication of pathogenic bacteria and blocking signal transducer and activator of transcription 1 and nuclear factor kappa-light-chain-enhancer of activated B cells inflammatory pathways. This research deepened the understanding of the mechanism underlying the postbiotics affecting goat milk digestion, which established a critical groundwork for the clinical application of postbiotics in infant complementary foods.
Topics: Animals; Pepsin A; Lacticaseibacillus casei; Trypsin; Allosteric Regulation; Angiotensin-Converting Enzyme Inhibitors; Peptides; Caseins; Goats
PubMed: 37410960
DOI: 10.1021/acs.jafc.3c02125