Viral infection can regulate the cell cycle, thereby promoting viral replication. Hijacking and altering the cell cycle are important for the virus to establish and maintain a latent infection. Previously, Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV)-latently infected P8-Se301-C1 cells, which grew more slowly than Se301 cells and interfered with homologous SeMNNPV superinfection, were established. However, the effects of latent and superinfection with baculoviruses on cell cycle progression remain unknown. In this study, the cell cycle profiles of P8-Se301-C1 cells and SeMNPV or Autographa californica multiple nucleopolyhedrovirus (AcMNPV)-infected P8-Se301-C1 cells were characterized by flow cytometry. The results showed that replication-related genes MCM4, PCNA, and BAF were down-regulated (p < 0.05) in P8-Se301-C1 cells, and the S phase of P8-Se301-C1 cells was longer than that of Se301 cells. P8-Se301-C1 cells infected with SeMNPV did not arrest in the G2/M phase or affect the expression of Cyclin B and cyclin-dependent kinase 1 (CDK1). Furthermore, when P8-Se301-C1 cells were infected with SeMNPV after synchronized treatment with hydroxyurea and nocodazole, light microscopy and qRT-PCR analysis showed that, compared with unsynchronized cells and S and G2/M phase cells, SeMNPV-infected P8-Se301-C1 cells in G1 phase induced G2/M phase arrest, and the amount of virus adsorption and intracellular viral DNA replication were significantly increased (p < 0.05). In addition, budded virus (BV) production and occlusion body (OB)-containing cells were both increased at 120 h post-infection (p < 0.05). The expression of Cyclin B and CDK1 was significantly down-regulated at 48 h post-infection (p < 0.05). Finally, the arrest of SeMNPV-infected G1 phase cells in the G2/M phase increased BV production (p < 0.05) and the number of OB-containing cells. In conclusion, G1 phase infection and G2/M arrest are favorable to SeMNPV proliferation in P8-Se301-C1 cells, thereby alleviating the homologous superinfection exclusion. The results contribute to a better understanding of the relationship between baculoviruses and insect cell cycle progression and regulation.

Viral infection can regulate the cell cycle, thereby promoting viral replication. Hijacking and altering the cell cycle are important for the virus to establish and maintain latent infection. Previously, Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) latently infected P8-Se301-C1 cells, which grew more slowly than Se301 cells and interfered with homologous SeMNNPV superinfection, were established. However, the effects of latent and superinfection with baculoviruses on cell cycle progression remain unknown. In this study, the cell cycle profiles of P8-Se301-C1 cells, and SeMNPV or Autographa californica mutiple nucleopolyhedrovirus (AcMNPV) infected P8-Se301-C1 cells were characterized by flow cytometry. The results showed that replication-related genes MCM4, PCNA, and BAF were down-regulated (p < 0.05) in P8-Se301-C1 cells and the S phase of P8-Se301-C1 cells was longer than that of Se301 cells. P8-Se301-C1 cells infected with SeMNPV did not arrest in G2/M phase and or affect the expression of Cyclin B and cyclin-dependent kinase 1 (CDK1). Furthermore, when P8-Se301-C1 cells were infected with SeMNPV after synchronized treatment with hydroxyurea and nocodazole, light microscopy and qRT-PCR analysis showed that compared with unsynchronized cells and S and G2/M phase cells, SeMNPV-infected P8-Se301-C1 cells in G1 phase induced G2/M phase arrest, and the amount of virus adsorption and intracellular viral DNA replication were significantly increased (p < 0.05). In addition, the BV production and the OB containing cells were both increased at 120 h post-infection (p < 0.05). The expression of Cyclin B and CDK1 was significantly down-regulated at 48 h post infection (p < 0.05). Finally, arrest of SeMNPV-infected G1 phase cells in the G2/M phase increased BV production (p < 0.05) and the number of OB containing cells. In conclusion, G1 phase infection and G2/M arrest are favorable to SeMNPV proliferation in P8-Se301-C1 cells, thereby alleviating the homologous superinfection exclusion. The results contribute to a better understanding of the relationship between baculoviruses and insect cell cycle progression regulation.

Sauce-aroma Baijiu is produced through a one-year cyclic process involving multiple fermentations and distillations. However, the dynamic changes and correlations among fermented grains (FG), distilled fermented grains (DG), heart liquor (HL) and tail liquor (TL) remain unclear. In this study, the physicochemical indicators and volatile compounds (VCs) from the 3rd to 6th distillation rounds were systematically analyzed. Across successive rounds, FG and DG exhibited similar trends in key physicochemical indicators, as did HL and TL. Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS) identified 76, 73, 80 and 93 VCs in FG, DG, HL and TL, respectively. Multivariate statistical analyses revealed significant inter-round differences in volatile profiles, and further indicated that total acids and water contents in FG were positively correlated with the majority of VCs in liquor. These results clarify the dynamic change of physicochemical and flavor components during Baijiu production and provide a basis for quality evaluation.

Hyperuricemia (HUA) is a metabolic disorder characterized by elevated serum uric acid (UA) levels resulting from the dysregulation of purine metabolism. The use of lactic acid bacteria (LAB) to alleviate HUA has attracted considerable attention. This study aimed to isolate LAB capable of degrading UA and purine precursors from traditionally fermented salt-free pickled vegetables in Guizhou Province, China, to evaluate their degradation characteristics, and to explore the underlying metabolic mechanism. A strain designated DF2 was isolated and identified as Limosilactobacillus fermentum (L. fermentum). In vitro experiments at 37 °C for 1 h showed that the DF2 strain could completely degrade guanosine, inosine, and adenosine, whereas its degradation rates for UA, xanthine, hypoxanthine, adenine, and guanine were 1.99%, 3.03%, 2.17%, 3.79%, and 12.12%, respectively. Notably, the strain converted the nucleosides to their purine bases and fully degraded guanosine-derived guanine within 7 h. Genomic analysis identified genes responsible for purine metabolism in the DF2 genome (accession number: SAMN62640203), and a metabolic pathway of UA and its precursors in the DF2 strain was proposed. These findings not only expand microbial resources for degrading UA and its precursors but also provide a basis for developing microbial agents to control UA levels in HUA.