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Infection of piglets with Glaesserella parasuis (G. parasuis) induces host immunosuppression. However, the mechanism underlying the immunosuppression of piglets remains unclear. Activation of the PD-1/PD-L1 axis has been shown to trigger host immunosuppression. Baicalin possesses anti-inflammatory and immunomodulatory functions. However, whether baicalin inhibits PD-1/PD-L1 activation and thus alleviates host immunosuppression has not been investigated. In this study, the effect of baicalin on the attenuation of piglet immunosuppression induced by G. parasuis was evaluated. Seventy piglets were randomly divided into the control group, infection group, levamisole group, BMS-1 group, 25 mg/kg baicalin group, 50 mg/kg baicalin group and 100 mg/kg baicalin group. Following pretreatment with levamisole, BMS-1 or baicalin, the piglets were challenged with 1 × 108 CFU of G. parasuis. Our results showed that baicalin, levamisole and BMS-1 modified routine blood indicators and biochemical parameters; downregulated IL-1β, IL-10, IL-18, TNF-α and IFN-γ mRNA expression; and upregulated IL-2 and IL-8 mRNA expression in blood. Baicalin, levamisole and BMS-1 increased the proportions of CD3+ T cells, CD3+CD4+ T cells, CD3+CD8+ T cells and CD3–CD21+ B cells in the splenocyte population, increased the proportions of CD3+ T cells, CD3+CD4+ T cells and CD3+CD8+ T cells in the blood, and inhibited PD-1/PD-L1 and TIM-3 activation. Baicalin, levamisole and BMS-1 reduced p-PI3K, p-Akt, and p-mTOR expression, the p-MEK1/2/MEK1/2 and p-ERK1/2/ERK1/2 ratios and increased RAS expression. Baicalin, levamisole and BMS-1 provided substantial protection against G. parasuis challenge and relieved tissue histopathological damage. Our findings might provide new strategies for controlling G. parasuis infection and other immunosuppressive diseases. [ABSTRACT FROM AUTHOR]

Glaesserella parasuis (G. parasuis) induces vascular damage and systemic inflammation. However, the mechanism by which it causes vascular damage is currently unclear. Baicalin has important anti-inflammatory, antibacterial and immunomodulatory functions. In this study, we explored the ability of baicalin and probenecid to protect against G. parasuis challenge in a piglet model. Sixty piglets were randomly divided into a control group; an infection group; a probenecid group; and 25 mg/kg, 50 mg/kg and 100 mg/kg baicalin groups. The probenecid group and the 25 mg/kg, 50 mg/kg and 100 mg/kg baicalin groups were injected intramuscularly with 20 mg/kg body weight (BW) probenecid and 25 mg/kg BW, 50 mg/kg BW and 100 mg/kg BW baicalin, respectively. All piglets except those from the control group were injected intraperitoneally with 1 × 108 CFU of G. parasuis. The control group was injected intraperitoneally with TSB. The results showed baicalin and probenecid protected piglets against G. parasuis challenge, improved body weight and decreased temperature changes in piglets. Baicalin and probenecid attenuated IL-1β, IL-10, IL-18, TNF-α and IFN-γ mRNA levels in the blood for 48 h, inhibited the production of the nucleosides ATP, ADP, AMP and UMP from 24 to 72 h, reduced Panx-1/P2Y6/P2X7 expression, weakened NF-kB, AP-1, NLRP3/Caspase-1 and ROCK/MLCK/MLC signalling activation, and upregulated VE-cadherin expression in the blood vessels of piglets challenged with G. parasuis. Baicalin and probenecid alleviated pathological tissue damage in piglets induced by G. parasuis. Our results might provide a promising strategy to control and treat G. parasuis infection in the clinical setting. [ABSTRACT FROM AUTHOR]

Monitoring of reactive oxygen species (ROS), such as O2˙−, etc., in organisms is of great significance, not only for their essential role in biological processes, but their excessive production may also result in many diseases. Flavin (FL) is a fluorophore that naturally exists in flavoenzymes, and its fluorescent emission (FE) becomes negligible when reduced. This enables the application of FL derivatives as fluorescent sensors for ROS. We presented a theoretical investigation to address the impact of amino substitution on the photophysical properties of aminoflavins (AmFLs). Resulting from the interplay of electronic and positional effects, amination at C8 enhances the electronic coupling between the ground state and the first singlet excited state by enlarging the adiabatic energy change of the electronic transitions and the emission transition dipole moments, weakens the vibronic coupling by decreasing the contribution of isoalloxazine to the frontier molecular orbitals, redshifts the absorption band, and enhances the fluorescent emission drastically in 8AmFL. The theoretically estimated fluorescent emission intensity of 8AmFL is ∼40 times that of FL, suggesting its potential application as a fluorescent sensor. [ABSTRACT FROM AUTHOR]

This work investigates the off-state leakage characteristics of AlN/GaN/AlGaN high electron mobility transistors (HEMTs) on Si substrate with varying mesa depths and uncovers the existence of a parasitic channel associated with the AlGaN back barrier. Significant differences in off-state leakage up to three orders of magnitude were observed between devices fabricated using different mesa depths. The electrical properties of AlN/GaN/AlGaN HEMTs were measured, and it was found that there is a N-type parasitic channel in the unintentionally doped AlGaN back-barrier. Analysis of the isolation test structure, which retains this parasitic channel, reveals a buffer leakage of 12.8 mA/mm and a sheet resistance of 7739.1 Ω/sq, as a result of the parasitic channel. The depletion electric field strength of the parasitic channel is 3.2 × 105 V/cm. Temperature-dependent I–V curves obtained from the isolation area affirm that the primary leakage mechanism is two-dimensional variable range hopping along the sidewall. As the isolation distance extends from 3 to 5 μm, the slope of the fitting line decreases from −53.14 to −126.11 due to increased resistance. [ABSTRACT FROM AUTHOR]