Our previous research showed that icariin (1) and its phosphorylated structural modification (2) improved the survival and attenuated oxidative stress and liver dysfunction induced by duck virus hepatitis. In this paper, we were one step closer to determine the structure of phosphorylation icariin (2) by the FT-IR, HRESIMS and 13C NMR. Anti-DHAV activities of 1 and 2 were compared in duck embryonic hepatocytes (DEHs) cultured in vitro and by artificial infection method in vivo. Additionally, the antiviral mechanisms of replication/release in vitro and the DHAV gene expression in vivo of 1 and 2 were analyzed. Compound 2's molecular formula was C33H42O18P. The results indicated that 1 and 2 effectively resisted DHAV invading DEHs, that they decreased the mortality of ducklings challenged with DHAV, and that 2 performed more effectively. 1 and 2 performed evenly on DHAV release; however, 2 restrained virus replication far more effectively. Since the anti-DHAV mechanisms of 1 and 2 in vitro probably involve suppression of replication and release, 2’s better performance in anti-DHAV may result from its far more effectively inhibiting virus replication. The compound 2's chemical structure was defined as 8-prenylkaempferol-4'-methylether-3-rhamnosyl-7-(6'''-phosphate)-glycoside. 1 and 2 exhibited anti-virus activity on DHAV. Our results suggest that 1 and 2 might become an anti-virus plant material candidate.

(1) Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a zoonotic pathogen that causes endocarditis, pneumonia, and skin diseases in humans and livestock. (2) Methods: The antibacterial effect of the total flavonoid against MRSA (ATCC43300) extracted from the Agrimonia pilosa Ledeb. (A. pilosa Ledeb) was evaluated by the microdilution method. The oxidative stresses in MRSA were evaluated by the levels of intracellular hydrogen peroxide (H₂O₂), reactive oxygen species (ROS), and oxidative stress-related genes. The DNA oxidative damage was tested by the 8-hydroxy-2′-deoxyguanosine (8-OHdG) and DNA gel electrophoresis. The differentially expressed proteins were determined by the method of SDS-PAGE and NanoLC-ESI-MS/MS, while the mRNAs of differential proteins were determined by Real-Time PCR. The changes of ultra-structures in MRSA were observed by Transmission Electron Microscope (TEM). (3) Results: The minimum inhibitory concentration (MIC) of the total flavonoid against MRSA was recorded as 62.5 μg/mL. After treatment with the total flavonoid, the levels of intracellular H₂O₂ and ROS were increased and the gene expressions against oxidative stress (SodA, katA, TrxB) were decreased (p < 0.01), while the gene expression for oxidative stress (PerR) was increased (p < 0.01). The level of intracellular 8-OHdG in MRSA was increased (p < 0.01) and the DNA was damaged. The results of TEM also showed that the total flavonoid could destroy the ultra-structures in the bacteria. (4) Conclusions: The total flavonoid extracted from the A. pilosa Ledeb can induce the oxidative stress that disturbed the energy metabolism and protein synthesis in MRSA.

In order to compare the pathogenicity of different Tembusu virus (TMUV) strains from geese, ducks and chickens, 56 5-day-old Cherry Valley ducklings which were divided into 7 groups and infected intramuscularly with 7 x 10(5) PFU/ml per duck of six challenge virus stocks. The clinical signs, weight gain, mortality, macroscopic and microscopic lesions, virus loads in sera of 1, 3, 5, 7, 11 and 14 dpi and serum antibody titers were examined. The results showed that these viruses could make the young ducks sick, but the clinical signs differed with the different species-original strains. All the experimental groups lose markedly in weight gain compared to the control, but there were no obvious distinctions in weight gains, as well as macroscopic and microscopic lesions of dead ducks between the infected groups. However, the groups of waterfowl-derived strains (from geese and ducks) showed more serious clinical signs and higher relative expressions of virus loads in sera than those from chicken-derived. The mortality of waterfowl groups was 37.5%, and the greatest mortality of chicken groups was 12.5%. The serum antibodies of the geese-species group JS804 appeared earlier and were higher in the titers than others. Taken toghter, the pathogenicity of waterfowl-derived TMUV was more serious than chicken-derived TMUV and JS804 could be chosen as one TMUV vaccine strain to protect from the infection.

Introduction: Coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), canine coronavirus (CCoV), and feline infectious peritonitis virus (FIPV), have the potential for interspecies transmission. These viruses can be present in complex environments where humans, dogs, and cats coexist, posing a significant threat to both human and animal safety.Methods and results: In this study, we developed a novel multiplex TaqMan-probe-based real-time PCR assay for the simultaneous detection and differentiation of SARS-CoV-2, CCoV, and FIPV. Specific primers and TaqMan fluorescent probes were designed based on the N region of SARS-CoV-2 and FIPV, as well as the S region of CCoV, which demonstrated a remarkable sensitivity and specificity toward the targeted viruses, as few as 21.83, 17.25 and 9.25 copies/μL for SARS-CoV-2, CCoV and FIPV, respectively. The standard curve constructed by the optimized method in our present study showed a high amplification efficiency within or near the optimal range of 91% to 116% and R(2) values were at least 0.95 for the abovementioned coronaviruses. A total of 91 samples, including six plasmid mixed mock samples, four virus fluid mixing simulated samples, and 81 clinical samples, were analyzed using this method. Results demonstrated strong agreement with conventional approaches.Discussion: By enabling the simultaneous detection of three viruses, this method enhances testing efficiency while decreasing costs. Importantly, it provides a valuable tool for the prevalence and geographical distribution of suspected and co-infected animals, ultimately contributing to the advancement of both animal and public health.

Avibacterium paragallinarum (Av. paragallinarum), the causative agent of infectious coryza, imposes substantial economic burdens on the poultry industry by inducing growth retardation in broilers and reducing egg production in laying hens by up to 40%. Disease control is hindered by the limited efficacy of available vaccines and the increasing prevalence of antibiotic resistance—challenges that are exacerbated by the pathogen’s capacity to form biofilms, which facilitate bacterial persistence and enhance drug tolerance. To systematically elucidate the genetic determinants underlying biofilm formation in Av. Paragallinarum, we constructed a high-density random mutant library using mini-Tn5 transposon mutagenesis, comprising 3106 individual mutants. Phenotypic screening via crystal violet staining identified 188 mutants displaying altered biofilm-forming capacity relative to the wild-type strain, including 172 with enhanced and 16 with reduced biofilm formation. Sequencing of transposon insertion sites in these mutants revealed 105 disrupted genes involved in diverse biological pathways, including amino acid metabolism, quorum sensing, and transmembrane transport. A representative subset of eight mutants was selected for detailed phenotypic characterization. Their biofilm phenotypes were consistent with the initial screening results; certain mutants exhibited markedly enhanced biofilm formation (e.g., Tn-2206), whereas others, including Tn-1504, Tn-2428, and Tn-2859, showed significant reductions in biofilm production. Notably, these three biofilm-deficient mutants—harboring disruptions in a TonB-dependent receptor (Tn-1504), a GntP family permease (Tn-2428), and a hypothetical protein (Tn-2859)—displayed drastically attenuated virulence in vitro. Compared with the wild-type strain, these mutants exhibited reductions in cytotoxicity (up to 66.38%), cell adhesion (up to 50.68%), and invasive capacity, while maintaining normal growth kinetics. These findings indicate that the identified genes may play crucial roles in biofilm-associated virulence and highlight Tn-1504, Tn-2428, and Tn-2859 as promising candidates for the development of live attenuated vaccines. Collectively, this study provides a comprehensive genetic foundation for the rational design of novel anti-biofilm strategies against Av. paragallinarum.

Background: The root of Schisandra propinqua (Wall.) Baill. var. sinensis Oliv is a traditional ethnomedicine in China; it was widely used to treat abscesses, sores, carbuncles, rheumatism, and so on. The purpose of this study was to elucidate the bacteriostatic mechanism of the ethyl acetate extract from the root of Schisandra propinqua (Wall.) Baill. var. Sinensis Oliv (Xiao Xue Teng) against Staphylococcus aureus ATCC 25923 (S. aureus ATCC 25923). Methods: Bioactive bacteriostatic constituents in Xiao Xue Teng were identified through Hybrid Quadrupole-TOF LC/MS/MS. The minimum inhibitory concentration (MIC) of Xiao Xue Teng against S. aureus ATCC 25923 was determined using the microbroth dilution method. A time–kill curve analysis was used to evaluate the bacteriostatic effects. SDS-PAGE coupled with nano-liquid NanoLC-ESI-MS/MS, real-time PCR, and scanning electron microscopy (SEM) was used to study the bacteriostatic mechanism of Xiao Xue Teng against S. aureus ATCC 25923. Results: The MIC of Xiao Xue Teng against S. aureus ATCC 25923 was determined to be 15.625 µg/mL. The translation initiation factor (IF-2) and elongation factor (EF-Tu) were significantly decreased in S. aureus ATCC 25923 after treatment with Xiao Xue Teng, while the proteins SodA and AhpC were obviously increased. The intracellular levels of total reactive oxygen species (ROS) and hydrogen peroxide (H₂O₂) were significantly increased (p < 0.01) after the treatment with Xiao Xue Teng. Concurrently, the activities of SOD, CAT and GSH-Px were significantly increased (p < 0.01). Moreover, cellular swelling and shrinkage were observed using SEM. Conclusions: The bacteriostatic mechanism of Xiao Xue Teng against S. aureus ATCC 25923 was related to eliciting oxidative stress, inhibiting protein synthesis and enhancing cytoplasmic membrane permeability.