Cooperative interactions between Veillonella ratti and Lactobacillus acidophilus ameliorate DSS-induced ulcerative colitis in mice.

Veillonella and Lactobacillus species are key regulators of a healthy gut environment through metabolic cross-feeding, influencing lactic acid and short-chain fatty acid (SCFA) levels, which are crucial for gut health. This study aims to investigate how Veillonella ratti (V. ratti) and Lactobacillus acidophilus (LA) interact with each other and alleviate dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in a mouse model. We assess their metabolic interactions regarding carbon sources through co-culturing in a modified medium. In the in vitro experiments, V. ratti and LA were inoculated in mono-cultures and co-culture, and viable cell counts, OD600, pH, lactic acid, glucose and SCFAs were measured. For the in vivo experiment, 60 C57BL/6 mice were randomly divided into five groups and administered V. ratti and LA alone or in combination via oral gavage (1 × 109 CFU mL-1 per day per mouse) for 14 days. On the seventh day, 2.5% DSS was added to the drinking water to induce colitis. The effects of these probiotics on UC were evaluated by assessing intestinal barrier integrity and intestinal inflammation in the gut microenvironment. In vitro results demonstrated that co-culturing V. ratti with LA significantly increased viable cell numbers, lactic acid production, and SCFA production, while reducing pH and glucose levels in the medium. In vivo findings revealed that intervention with V. ratti, particularly in combination with LA, alleviated symptoms, including weight loss, colon shortening, and tissue damage. These probiotics mitigated intestinal inflammation by down-regulating pro-inflammatory molecules, such as IL-6, IL-1ß, IL-γ, iNOS, and IFN-γ, as well as oxidative stress markers, including MDA and MPO. Concurrently, they upregulated the activity of anti-inflammatory enzymes, namely, SOD and GSH, and promoted the production of SCFAs. The combined intervention of V. ratti and LA significantly increased acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and total SCFAs in cecal contents. Furthermore, the intervention of V. ratti and LA increased the abundance of beneficial bacteria, such as Akkermansia, while reducing the abundance of harmful bacteria, such as Escherichia-Shigella and Desulfovibrio, thereby mitigating excessive inflammation. These findings highlight the enhanced therapeutic effects resulting from the interactions between V. ratti and LA, demonstrating the potential of this combined probiotic approach.

Comparison of gelling properties and flow behaviors of microbial transglutaminase (MTGase) and pectin modified fish gelatin.

The gelling and structural properties of microbial transglutaminase (MTGase) and pectin modified fish gelatin were compared to investigate their performances on altering fish gelatin properties. Our results showed that within a certain concentration, both MTGase and pectin had positive effects on the gelation point, melting point, gel strength, textural, and swelling properties of fish gelatin. Particularly, low pectin content (0.5%, w/v) could give fish gelatin gels the highest values of gel strength, melting temperature, and hardness. Meantime, flow behavior results showed that both MTGase and pectin could increase fish gelatin viscosity without changing its fluid characteristic, but the latter gave fish gelatin higher viscosity. Both MTGase and pectin could increase the lightness of fish gelatin gels but decreases its transparency. More importantly, fluorescence and UV absorbance spectra, particle size distribution, and confocal microscopy results indicated that MTGase and pectin could change the structure of fish gelatin with the formation of large aggregates. Compared with MTGae modified fish gelatin, pectin could endow fish gelatin had similar gel strength, thermal and textural properties to pig skin gelatin.

Deviation from the Maxwell-Cattaneo law: Role of asymmetric interparticle interactions.

Nonstationary heat conduction in a few one-dimensional nonlinear lattices is studied numerically based on the Maxwell-Cattaneo (MC) law. We simulate the relaxation process and calculate the magnitudes of the temperature oscillation A(T)(t) and the local heat current oscillation A(j)(t). A phase difference between A(T)(t) and A(j)(t) is observed, which not only verifies the existence of the time lag τ in the MC law but also provides a better way of determining the critical wavelength L(*) that separates between oscillatory and diffusive relaxation modes. However, clear deviations from the MC law are observed. Not only do the decay exponents differ from the theoretical expectations, but, more importantly, suboscillation in the diffusive regime, which is not expected by the MC law, is found in the lattices with asymmetric interactions as well. These findings imply that higher-order effects must be considered in order to well describe the nonstationary heat conduction process in these systems.

Heat-current correlation loss induced by finite-size effects in a one-dimensional nonlinear lattice.

The Green-Kubo formula provides a mathematical expression for heat conductivity in terms of integrals of the heat-current correlation function, which should be calculated in the thermodynamic limit. In finite systems this function generally decreases, i.e., it decays faster than it does in infinite systems. We compared the values of the correlation function in a one-dimensional purely quartic lattice with various lengths, and found that this loss is much smaller than is conventionally estimated. By studying the heat diffusion process in this lattice, we found that, in contrast to the conventional belief, the collisions between sound modes do not noticeably affect the current correlation function. Therefore, its loss being surprisingly small can be well understood. This finding allows one to calculate the heat conductivity in a very large system with desirable accuracy by performing simulations in a system with much smaller size, and thus greatly broadens the application of the Green-Kubo method.