The development of effective vaccines and delivery systems in aquaculture is a long-term challenge for controlling emerging and reemerging infections. Cost-efficient and advanced nanoparticle vaccines are of tremendous applicability in prevention of infectious diseases of fish. In this study, dihydrolipoamide dehydrogenase (DLDH) antigens of Vibrio alginolyticus were loaded into mesoporous silica nanoparticles (MSN) to compose the vaccine delivery system. Hydroxypropyl methylcellulose phthalate (HP55) was coated to provide protection of immunogen. The morphology, loading capacity, acid-base triggered release were characterized and the toxicity of nanoparticle vaccine was determined in vitro. Further, the vaccine immune effects were evaluated in large yellow croaker via oral administration. In vitro studies confirmed that the antigen could be stable in enzymes-rich artificial gastric fluid and released under artificial intestinal fluid environment. In vitro cytotoxicity assessment demonstrated the vaccines within 120 μg/ml have good biocompatibility for large yellow croaker kidney cells. Our data confirmed that the nanoparticle vaccine in vivo could elicit innate and adaptive immune response, and provide good protection against Vibrio alginolyticus challenge. The MSN delivery system prepared may be a potential candidate carrier for fish vaccine via oral administration feeding. Further, we provide theoretical basis for developing convenient, high-performance, and cost-efficient vaccine against infectious diseases in aquaculture.

Heat-stable antifungal factor (HSAF) isolated from Lysobacter enzymogenes has shown a broad-spectrum of antifungal activities. However, little is known about its mode of action. In this study, we used the model filamentous fungus Neurospora crassa to investigate the antifungal mechanism of HSAF. We first used HSAF to treat the N. crassa strain at different time points. Spore germination, growth phenotype and differential gene expression analysis were conducted by utilizing global transcriptional profiling combined with genetic and physiological analyses. Our data showed that HSAF could significantly inhibit the germination and aerial hyphae growth of N. crassa. RNA-seq analysis showed that a group of genes, associated with cell wall formation and remodeling, were highly activated. Screening of N. crassa gene deletion mutants combined with scanning electron microscopic observation revealed that three fungal cell wall integrity-related genes played an important role in the interaction between N. crassa and L. enzymogens. In addition, Weighted Gene Co-Expression Network Analysis (WGCNA), accompanied by confocal microscopy observation revealed that HSAF could trigger autophagy-mediated degradation and eventually result in cell death in N. crassa. The findings of this work provided new insights into the interactions between the predatory Lysobacter and its fungal prey.

Over the past decade, diseases associated with fowl adenoviruses (FAdVs) have exhibited a new epidemic trend worldwide. The presence of numerous FAdVs serotypes, combined with the virus’s broad host range, positions it as a significant pathogen in the poultry industry. In the current context of intensive poultry production and global trade, co-infections involving multiple FAdVs serotypes, as well as co-infections with FAdVs alongside infectious bursal disease or infectious anemia virus, may occur within the same region or even on the same farm. The frequency of these outbreaks complicates the prevention and control of FAdVs. Therefore, the development of effective, targeted vaccines is essential for providing technical support in the management of FAdVs epidemics. Ongoing vaccine research aims to improve vaccine efficacy and address the challenges posed by emerging FAdVs outbreaks. This review focuses on vaccines developed and studied worldwide for various serotypes of FAdVs in the past decade. It encompasses inactivated vaccines, live attenuated vaccines, e.g., host-adapted attenuated vaccines and gene deletion vaccines, viral vector vaccines, and subunit vaccines (including VLP proteins and chimeric proteins). The current limitations and future development directions of FAdVs vaccine development are also proposed to provide a reference for new-generation vaccines and innovative vaccination strategies against FAdVs, as well as for the rapid development of highly effective vaccines.

Tetrahymena is commonly used as an alternative eukaryotic system for efficiently expressing heterologous genes. In this study, we inserted the non-structural (NS) 1 gene of avian influenza virus (AIV) into the shuttle vector pD5H8 and transformed conjugating T. thermophila with the recombinant plasmid pD5H8-NS1 by particle bombardment. Positive transformants were selected with paromomycin. We demonstrated that the NS1 protein could be expressed steadily following induction with cadmium in this Tetrahymena system. An enzyme-linked immunosorbent assay detection method was preliminary established using the expressed protein as coating antigens for serodiagnosis. This is the first study in which a Tetrahymena expression system was employed for the expression of the AIV NS1 protein, and it provides a good basis for the development of differential diagnostic kits and vaccines for the prevention and control of avian influenza.