Guoyuan Wen

Marine bacteria represent a vast and largely untapped resource for biotechnological innovation, offering solutions to global challenges in health, sustainability, and environmental conservation. The ocean’s unique conditions have driven marine bacteria to evolve diverse metabolic capabilities, resulting in the production of bioactive compounds, enzymes, and other metabolites with wide-ranging applications. Recent advances in high-throughput sequencing, metagenomics, and analytical chemistry have unlocked new opportunities for leveraging these microorganisms in fields as varied as medicine, agriculture, and bioremediation. This review highlights the role of marine bacteria in the One Health framework, showcasing their contributions to antimicrobial discovery, nutraceutical development, pathogen biocontrol, and environmental cleanup, including microplastic degradation. This review also examines emerging methodologies such as microbiome mining and advanced culturing techniques, which hold the key to realizing the full potential of marine bacteria in a sustainable bioeconomy. By bridging fundamental research with applied sciences, marine biotechnology promises to deliver transformative impacts on human, animal, and environmental health.

Diarrhea and impaired intestinal development are major constraints in newly hatched domestic pigeons raised for meat production, leading to reduced growth performance and increased reliance on antimicrobial interventions. Cecropin AD (CAD) is a broad-spectrum antimicrobial peptide with potential activity against bacterial pathogens and may represent an alternative strategy for improving intestinal health in poultry. In this study, we evaluated the safety and biological effects of a recombinant Newcastle disease virus (NDV) expressing CAD (rTS-CAD₃) in one-day-old domestic pigeons. Pigeons were inoculated with rTS-CAD₃, parental TS09-C, or PBS and monitored for growth performance, diarrhea incidence, viral RNA persistence, inflammatory responses, intestinal bacterial abundance, gut microbiota composition, intestinal morphology, and epithelial barrier function. rTS-CAD₃ caused no mortality, detected only transient viral RNA, and did not induce excessive inflammatory responses. Compared with TS09-C and PBS controls, rTS-CAD₃ significantly increased body weight gain and average daily gain while reducing diarrhea incidence. Importantly, rTS-CAD₃ decreased intestinal Escherichia coli abundance, reshaped the gut microbiota by reducing Proteobacteria and Escherichia–Shigella while increasing Firmicutes and Lactobacillus, improved villus height and the villus-to-crypt ratio, and enhanced occludin expression. These findings demonstrate that NDV-vectored CAD delivery can reduce intestinal bacterial burden, increase occludin expression, and alleviate diarrhea in domestic pigeons. The rTS-CAD₃ represents a promising antimicrobial peptide-based strategy for reducing spontaneous diarrhea and dependence on conventional antibiotics in poultry production.

Vaccination remains the core strategy for the prevention and control of Newcastle disease (ND). The inherent thermosensitivity of traditional Newcastle disease virus (NDV) vaccines imposes major limitations on their transportation, storage, and field application. To address these challenges, a novel liquid, thermostable, live ND vaccine was developed in the present study. Firstly, Tris/HCl buffer at near-neutral pH was identified as the optimal basic buffer system. On this basis, further screening and formulation optimization of vaccine stabilizers were conducted, and NDV strains with excellent thermal stability were used to verify the stability-conferring properties of the developed stabilizer. The results showed that the formulation composed of 0.5% gelatin, 4% trehalose, 0.1% L-glutamic acid, and 0.5% thiourea was confirmed as the optimal stabilizer for ND liquid vaccines. This formulation maintained the stable storage of the tested NDV for 12 months at 4 °C and exhibited promising stability for 30 days at 25 °C, marking a significant advancement toward development thermostable NDV vaccines that are independent of a continuous cold chain. More importantly, the liquid vaccine stored at 4 °C for 12 months still induced high levels of NDV-specific antibodies in specific pathogen-free chicks and provided 100% protective efficacy against challenge with virulent NDV. In conclusion, the liquid vaccine stabilizer developed in this study not only significantly enhanced the thermostability of the vaccine but also effectively maintained its immunogenicity, thereby providing an important theoretical basis for the research and development of liquid ND vaccines.

Novel goose parvovirus (NGPV), a genetic variant of goose parvovirus, has been spreading throughout China since 2015 and mainly infects ducklings with the symptoms of growth retardation, beak atrophy, and protruding tongue, leading to huge economic losses every year. A safe and effective vaccine is urgently needed to control NGPV infection. In this study, virus-like particles (VLPs) of NPGV were assembled and evaluated for their immunogenicity. The VP2 protein of NGPV was expressed in Spodoptera frugiperda insect cells using baculovirus as vector. The VP2 protein was efficiently expressed in the nucleus of insect cells, and the particles with a circular or hexagonal shape and a diameter of approximately 30 nm, similar to the NGPV virion, were observed using transmission electron microscopy (TEM). The purified particles were confirmed to be composed of VP2 using western blot and TEM, indicating that the VLPs of NGPV were successfully assembled. Furthermore, the immunogenicity of the VLPs of NGPV was evaluated in Cherry Valley ducks. The level of NGPV serum antibodies increased significantly at 1–4 weeks post-immunization. No clinical symptoms or deaths of ducks occurred in all groups after being challenged with NGPV at 4 weeks post-immunization. There was no viral shedding in the immunized group. However, viral shedding was detected at 3–7 days post-challenge in the non-immunized group. Moreover, VLPs can protect ducks from histopathological lesions caused by NGPV and significantly reduce viral load in tissue at 5 days post-challenge. Based on these findings, NGPV VLPs are promising candidates for vaccines against NGPV.