Animal models with characteristics of irritable bowel syndrome with diarrhea: current applications and future perspectives.

Irritable bowel syndrome with diarrhea (IBS-D) is a common intestinal condition that significantly impacts work efficiency and quality of life. The use of animal models is crucial for delving into the pathophysiology of IBS-D and exploring therapeutic options. However, a wide variety of animal models for IBS-D has been employed in previous studies, posing a considerable challenge for researchers in selecting a suitable model. In this review, conducted using the Web of Science database, we searched IBS-D-related research spanning from 2014 to 2023, described the differences in animal strains and modeling methods among various IBS-D features recapitulating models, summarized the frequency of model usage, pathogenesis, and pathological characteristics of these models, and discussed their current applications, limitations, and future perspectives. The objective is to offer theoretical guidance for future researchers, aiding them in choosing suitable animal models based on their experimental designs.

Exploring the Interactions of Soybean 7S Globulin with Gallic Acid, Chlorogenic Acid and (-)-Epigallocatechin Gallate.

In this study, the noncovalent interaction mechanisms between soybean 7S globulin and three polyphenols (gallic acid (GA), chlorogenic acid (CA) and (-)-epigallocatechin gallate (EGCG)) were explored and compared using various techniques. Fluorescence experiments showed that GA and EGCG had strong static quenching effects on 7S fluorescence, and that of CA was the result of multiple mechanisms. The interactions caused changes to the secondary and tertiary structure of 7S, and the surface hydrophobicity was decreased. Thermodynamic experiments showed that the combinations of polyphenols with 7S were exothermic processes. Hydrogen bonds and van der Waals forces were the primary driving forces promoting the binding of EGCG and CA to 7S. The combination of GA was mainly affected by electrostatic interaction. The results showed that the structure and molecular weight of polyphenols play an important role in their interactions. This work is helpful for developing products containing polyphenols and soybean protein.

Superoxide dismutase ameliorates oxidative stress and regulates liver transcriptomics to provide therapeutic benefits in hepatic inflammation.

Background: Oxidative stress refers to the imbalance between oxidants and antioxidants in organisms and often induces hepatic inflammation. Supplementing exogenous superoxide dismutase is an effective way to alleviate oxidative stress; however, the effects and mechanisms by which superoxide dismutase alleviates hepatic inflammation remain unclear. Methods: This study established a Kunming mouse model to verify and investigate the oxidative stress and hepatic inflammation-alleviating effects of the superoxide dismutase oral supplement that was prepared by our research group in a previous study. Results: The superoxide dismutase product significantly restored the body weight and liver alanine transaminase, aspartate aminotransferase, superoxide dismutase, catalase, glutathione, and glutathione peroxidase levels of oxidative stress induced mice. Moreover, exogenous superoxide dismutase significantly inhibited interleukin 1ß and interleukin 6 mRNA expression in the livers of mice with hepatic inflammation. Transcriptomic analysis indicated that superoxide dismutase had a significant inhibitory effect on Endog expression, alleviating oxidative stress damage, and mediating liver cell apoptosis by regulating the expression of Rab5if, Hnrnpab, and Ifit1. Conclusion: Our research verified the oxidative stress remediation effects of superoxide dismutase and its therapeutic role against hepatic inflammation. This study can lay a foundation for investigating the mechanism by which superoxide dismutase alleviates hepatic disease.

Nanosized copper particles induced mesangial cell toxicity via the autophagy pathway.

Nanosized copper particles (nano Cu) have been incorporated into products in multiple industries, although studies have demonstrated that these particles are nephrotoxic. We investigated the cytotoxicity of nanosized copper particles on rat mesangial cells and measured rates of apoptosis, the expression of caspase-3, and generation of reactive oxygen species. We also measured autophagy through the acridine orange (AO) staining and expression of Beclin-1, microtubule-associated protein 1 light chain 3, and p62 to screen the underlying mechanism of toxicity. Nanosized copper particles inhibited mesangial cell viability, up-regulated the activity of caspase-3, and increased the rates of apoptosis and the generation of reactive oxygen species in a concentration-dependent manner. Exposure to nano Cu increased the formation of acidic vesicular organelles and the expression of Beclin-1, microtubule-associated protein 1 light chain 3, and p62, and treatment with an autophagy inhibitor reduced nephrotoxicity. This indicated that the autophagy pathway is involved in the toxicity induced by nanosized copper particles to mesangial cells. This finding can contribute to the development of safety guidelines for the evaluation of nanomaterials in the future.

Evidence from Thermal Aging Indicating That the Synergistic Effect of Glyoxal and Sodium Sulfite Improved the Thermal Stability of Conformational Modified Xanthan Gum.

Xanthan gum is prone to thermal oxidative degradation, which limits its applications. However, conformational changes in xanthan gum and appropriate stabilizers may improve its thermal stability. Therefore, in this study, we aimed to establish a strategy to maintain the viscosity of xanthan gum during long-term storage at high temperatures. We modified the original strain used for xanthan gum production by genetic engineering and added stabilizers during the production process. The structure and thermal stability of the resulting xanthan gum samples were then determined. Pyruvyl deficiency, combined with the addition of sodium sulfite and glyoxal during the production process, was found to significantly improve the maintenance of viscosity. The apparent viscosity of the new xanthan gum solution remained above 100 mPa·s after being stored at 90 °C for 48 days. Fourier-transform infrared spectra and scanning electron microscopy images showed that pyruvate-free xanthan gum with added stabilizers had more extensive cross-linking than natural xanthan gum. In conclusion, these findings may contribute to the use of xanthan gum in applications that require high temperatures for a long period of time.

Nanosized copper particles induced mesangial cell toxicity via the autophagy pathway

Nanosized copper particles (nano Cu) have been incorporated into products in multiple industries, although studies have demonstrated that these particles are nephrotoxic. We investigated the cytotoxicity of nanosized copper particles on rat mesangial cells and measured rates of apoptosis, the expression of caspase-3, and generation of reactive oxygen species. We also measured autophagy through the acridine orange (AO) staining and expression of Beclin-1, microtubule-associated protein 1 light chain 3, and p62 to screen the underlying mechanism of toxicity. Nanosized copper particles inhibited mesangial cell viability, up-regulated the activity of caspase-3, and increased the rates of apoptosis and the generation of reactive oxygen species in a concentration-dependent manner. Exposure to nano Cu increased the formation of acidic vesicular organelles and the expression of Beclin-1, microtubule-associated protein 1 light chain 3, and p62, and treatment with an autophagy inhibitor reduced nephrotoxicity. This indicated that the autophagy pathway is involved in the toxicity induced by nanosized copper particles to mesangial cells. This finding can contribute to the development of safety guidelines for the evaluation of nanomaterials in the future.

Construction and potential application of bacterial superoxide dismutase expressed in Bacillus subtilis against mycotoxins.

Oxidative stress, which could be evoked by numerous inducements including mycotoxins like deoxynivalenol (DON), cause severe damages to organisms. Antioxidants are promising protectants against oxidative stress that could be applied in pharmaceutical, cosmetic, and food and feed industries. In this study, a thermostable and acidophilic superoxide dismutase (AaSOD) was used to develop an antioxidant product that can potentially protect organisms from oxidative stress related damages. The enzyme was successfully expressed as an extracelluar protein in Bacillus subtilis with a high yield. To obtain a feasible protocol for industrial production of AaSOD, the fermentation mediums that are commonly used for culturing B. subtilis were screened, the feasibility of expressing AaSOD without antibiotic as selection pressure was confirmed, and the effect of using lactose as an inducer instead of isopropyl-ß-d-thiogalactoside (IPTG) was investigated. Batch fermentation was conducted to validate the optimized conditions for AaSOD production, and 6530 U mL-1 of SOD activity was obtained in the fermentation broth. The dry powder product of AaSOD with an activity of 22202 U g-1 was prepared by spray-drying and was administrated on zebrafish to test its function as a protectant against DON, and thus gained a significant redress of the reactive oxygen species (ROS) accumulation induced by DON. Taken together, this study provides a feasible protocol to prepare the AaSOD-based antioxidant product that is potentially applied in livestock industry.

Thermoacidophilic Alicyclobacillus Superoxide Dismutase: Good Candidate as Additives in Food and Medicine.

Thermoacidophilic Alicyclobacillus strains attract great interests as the resource of thermostable or acidic enzymes. In this study, a putative gene encoding superoxide dismutase (AaSOD) was identified in a thermoacidophilic Alicyclobacillus strain. With a 16-fold activity observed, the AaSOD activity expressing in the medium of manganese enrichment was much higher than that in the iron medium. In addition, the purified AaSOD can be reconstituted exclusively with either Fe2+ or Mn2+, with its Mn-bound protein showing 25-fold activity than that of Fe-bound form. The optimal temperature for AaSOD reaction was 35°C, and was highly stable at any certain temperature up to 80°C. Of particular interest, the enzyme is found to be very stable across a wide pH range spanning from 2.0 to 10.0, which confers its robust stability in the acidic stomach environment and implies striking potentials as food additive and for medical use.

Promoter engineering for high ectoine production in a lower saline medium by Halomonas hydrothermalis Y2.

OBJECTIVES: For the stress from fermenters, downstream processing equipment, and wastewater treatment to be alleviated, lowering salt-dependence in the ectoine synthesis process is of great significance in the moderately halotolerant Halomonas hydrothermalis Y2. RESULTS: In H. hydrothermalis Y2, the σ70- and σ38-controlled promoters of ectA are predicted to be involved in the osmotic regulation of ectoine synthesis. By substituting the ectA promoter with a promoter P265 that identified in the outer membrane pore protein E of H. hydrothermalis Y2, the salt dependence of ectoine synthesis was significantly decreased. In the 500-ml flask containing various NaCl contents, the engineered strain (p/Y2/△ectD/△doeA) showed a remarkably enhanced ability in ectoine synthesis, especially under lower saline stress. After a 36-h fed-batch fermentation in the 1-l fermenter, p/Y2/△ectD/△doeA synthesized 11.5 g ectoine l-1 in the presence of 60 g NaCl-1 l, with a high 0.32 g ectoine l-1 h-1 productivity, a specific productivity of 512.2 mg ectoine per g cell dry weight (CDW)-1, and an excretion ratio of 67 % ectoine. CONCLUSIONS: As no impaired growth was observed in strain p/Y2/△ectD/△doeA while ectoine synthesis was increased, this promoter engineering strategy provides a practical protocol for lowering the salt-dependence of ectoine synthesis in this moderately halotolerant strain.

Ultrafast Vibrational Energy Transfer through the Covalent Bond and Intra- and Intermolecular Hydrogen Bonds in a Supramolecular Dimer by Two-Dimensional Infrared Spectroscopy.

In this work, the structural fluctuations and vibrational energy transfer dynamics in a supramolecular homodimer model, which is composed of 2-(9-anthracene)ureido-6-(1-undecyl)-4[1H]-pyrimidinone (UPAn) with quadruple intermolecular and single intramolecular hydrogen bonds (HBs), have been examined using ultrafast two-dimensional infrared (2D IR) and steady-state IR spectroscopies. A less structurally fluctuating intermolecular HB is found between the pyrimidinone C═O and ureido N-H groups. However, a larger structurally fluctuating intramolecular HB is suggested by the equilibrium and dynamical line-shape measurements of the ureido C═O stretch. Further, dynamical time-dependent 2D IR diagonal and off-diagonal signals show that intra- and intermolecular vibrational energy transfer processes occur on the picosecond timescale, where the latter is more efficient due to intermolecular hydrogen bonding interaction and through-space interaction.

Biopolymer from marine Athelia and its application on heavy oil recovery in heterogeneous reservoir.

Biopolymer produced from marine Athelia strain presented unique Pseudoplastic behaviors under extremely-high temperature and salinity conditions. Characteristic analysis with FT-IR spectroscopy, high performance liquid chromatography, 1H and 13C NMR and two-dimensional COSY and HMQC spectra showed the structure of ß-(1-6) glucans. Single-factor and orthogonal experiment design were used to optimize the yield, the maximum yield of the biopolymer was 28.32 g/L with 56.64% carbon conversion rate under optimized conditions. Economic investigation demonstrated that this novel biopolymer has great potential of commercialization with the competitive cost of $2896.04-5228.94 per ton for powder. Resistance factor and residual resistance factor were evaluated with core flooding experiments showed that this biopolymer had excellent performance of plugging capacity and profile modification, and indicating the great potential of application on heavy oil recovery.

Central-metal effect on intramolecular vibrational energy transfer of M(CO)5Br (M = Mn, Re) probed by two-dimensional infrared spectroscopy.

Vibrational energy transfer in transition metal complexes with flexible structures in condensed phases is of central importance to catalytical chemistry processes. In this work, two molecules with different metal atoms, M(CO)5Br (where M = Mn, Re), were used as model systems, and their axial and radial carbonyl stretching modes as infrared probes. The central-metal effect on intramolecular vibrational energy redistribution (IVR) in M(CO)5Br was investigated in polar and nonpolar solvents. The linear infrared (IR) peak splitting between carbonyl vibrations increases as the metal atom changes from Mn to Re. The waiting-time dependent two-dimensional infrared diagonal- and off-diagonal peak amplitudes reveal a faster IVR process in Re(CO)5Br than in Mn(CO)5Br. With the aid of density functional theory (DFT) calculations, the central-metal effect on IVR time linearly correlates with the vibrational coupling strength between the two involved modes. In addition, the polar solvent is found to accelerate the IVR process by affecting the anharmonic vibrational potentials of a solute vibration mode.

Efficient Intramolecular Vibrational Excitonic Energy Transfer in Ru3(CO)12 Cluster Revealed by Two-Dimensional Infrared Spectroscopy.

Trinuclear transition-metal carbonyl complex dodecacarbonyl triruthenium (Ru3(CO)12) is considered as one of the paradigms in cluster chemistry, which plays an important role in photocatalysis, photoenergy conversion, and synthetic chemistry. Due to structural symmetry (D3h point group), 12 carbonyl (C≡O) groups in the Ru3(CO)12 complex contribute to mainly three excitonic carbonyl stretching modes: E' (radial), A2″ (axial), and E' (axial). In this work, efficient intramolecular vibrational energy redistribution (IVR) processes among the three modes in this Ru-CO complex were observed to occur on the time scale of tens of picoseconds. The IVR processes were characterized in detail using a kinetic model and fitting to the waiting-time-dependent diagonal and off-diagonal signals of ultrafast two-dimensional infrared spectroscopy. In addition, the diagonal anharmonicities of the three C≡O stretching modes were determined to be quite close to one another, and the coupling-induced cross peaks were invariant because this Ru3(CO)12 cluster does not show picosecond fluxionality and hence their contributions were neglected in modeling the IVR processes. Our results provide a benchmark for understanding the excitonic nature of the vibrational excited states of the carbonyl vibrators and the associated efficient vibrational energy-flow pathways, in such multicentered transition-metal complexes, which are of key importance to their functions.