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Newcastle disease virus (NDV) is an oncolytic virus whose F protein cleavage activity is associated with viral infectivity. To explore the potential of modifying F protein cleavage activity to enhance antitumor effects, we constructed a recombinant NDV LaSota strain by replacing its F protein cleavage site with that from the mesogenic Beaudette C (BC) strain using reverse genetics techniques. The resulting virus, rLaSota-BC-RFP, demonstrated significantly enhanced infectivity and tumor cell suppression on the murine melanoma B16F10 cell, characterized by higher cytotoxicity and increased apoptosis compared to its parental strain, rLaSota-RFP. In vivo, rLaSota-BC-RFP treatment of B16F10 tumors in C57BL/6 mice resulted in significant tumor growth inhibition, improved survival rate, and induction of tumor-specific apoptosis and necrosis. Additionally, the rLaSota-BC-RFP treatment enhanced immunostimulatory effects within the tumor microenvironment (TME), characterized by increased infiltration of CD4+ and CD8+ T cells and elevated levels of antitumor immune modulator cytokines, including mouse IL-12, IFN-γ, IL-15, and TNF-α, in the rLaSota-BC-RFP-treated tumor tissues. Collectively, these findings demonstrate that the mesogenic F protein cleavage site enhances the oncolytic potential of the NDV LaSota strain, suggesting that rLaSota-BC-RFP is a promising oncolytic viral vector for gene delivery in cancer immunotherapy.

ABSTRACT Avipoxviruses are considered as significant viral pathogen infecting a wide range of domestic and wild bird species globally, yet the majority of avipoxviruses that infect the wild bird species remain uncharacterized and their genetic diversities remain unclear. In this study, we present a novel pathogenic avipoxvirus isolated from the cutaneous pox lesions of a wild oriental turtle dove (Streptopelia orientalis), tentatively named as turtle dovepox virus (TDPV). The avipoxvirus was isolated by using the chorioallantoic membranes of specific pathogen-free chicken embryos which showed characteristic focal pock lesions, followed by cytopathic effects in host cells infected with oriental turtle dovepox virus. An effort in sequencing the whole genome of the poxvirus using next-generation sequencing was given, and the first whole genome sequence of TDPV was obtained. The TDPV genome was 281,386 bp in length and contained 380 predicted open reading frames (ORFs). While 336 of the predicted ORFs showed homology to other characterized avipoxviruses, the other 44 ORFs were unique. Subsequent phylogenetic analyses showed that the novel TDPV shared the closest genetic evolutionary linkage with the avipoxviruses isolated from pigeon in South Africa and India, of which the TDPV genome had the highest sequence similarity (92.5%) with South African pigeonpox virus (FeP2). In conclusion, the sequenced TDPV is significantly different from any other avipoxviruses isolated from avian or other natural host species considering genomic architecture and observed sequence similarity index. Thus, it likely should be considered a separate species. IMPORTANCE Over the past few decades, avipoxviruses have been found in a number of wild bird species including the oriental turtle dove. However, there is no whole genome sequence information on avipoxviruses isolated from oriental turtle dove, leaving us unclear about the evolutionary linkage of avipoxviruses in oriental turtle dove and other wild bird species. Thus, we believe that our study makes a significant contribution because it is the first report of the whole genome sequence of TDPV isolated from a wild oriental turtle dove, which enriches the genomic information of the genus Avipoxvirus, furthermore, contributes to tracking the genetic evolution of avipoxviruses-infected oriental turtle dove species.

This research constructed a novel O3/CaO2/HCO3− system to degrade antibiotic oxytetracycline (OTC) in water. The results indicated that CaO2 and HCO3− addition could promote OTC degradation in an O3 system. There is an optimal dosage of CaO2 (0.05 g/L) and HCO3− (2.25 mmol/L) that promotes OTC degradation. After 30 min of treatment, approximately 91.5% of the OTC molecules were eliminated in the O3/CaO2/HCO3− system. A higher O3 concentration, alkaline condition, and lower OTC concentration were conducive to OTC decomposition. Active substances including ·OH, 1O2, ·O2−, and ·HCO3− play certain roles in OTC degradation. The production of ·OH followed the order: O3/CaO2/HCO3− > O3/CaO2 > O3. Compared to the sole O3 system, TOC and COD were easier to remove in the O3/CaO2/HCO3− system. Based on DFT and LC-MS, active species dominant in the degradation pathways of OTC were proposed. Then, an evaluation of the toxic changes in intermediates during OTC degradation was carried out. The feasibility of O3/CaO2/HCO3− for the treatment of other substances, such as bisphenol A, tetracycline, and actual wastewater, was investigated. Finally, the energy efficiency of the O3/CaO2/HCO3− system was calculated and compared with other mainstream processes of OTC degradation. The O3/CaO2/HCO3− system may be considered as an efficient and economical approach for antibiotic destruction.

The reverse genetics system of the Newcastle disease virus (NDV) has provided investigators with a powerful approach to understand viral molecular biology and vaccine development. It has been impressively improved with modified strategies since its first report, but it still poses some challenges. Most noteworthy, the genome complexity and length made full-length error-free cDNA assembly the most challenging and time-consuming step of NDV rescue. In the present study, we report a rapid full-length NDV genome construction with only a two-step ligation-independent cloning (LIC) strategy, which could be applied to distinct genotypes. In this approach, the genome of NDV was divided into two segments, and the cDNA clones were generated by RT-PCR followed by LIC. Subsequently, the infectious NDVs were rescued by co-transfection of the full-length cDNA clones and supporting plasmids expressing the NP, P, and L proteins of NDV in BHK-21 cells. Compared with the conventional cloning approaches, the two-step cloning method drastically reduced the number of cloning steps and saved researchers a substantial amount of time for constructing NDV infectious clones, thus enabling a rapid rescue of different genotypes of NDVs in a matter of weeks. Therefore, this two-step LIC cloning strategy may have an application to the rapid development of NDV-vectored vaccines against emerging animal diseases and the generation of different genotypes of recombinant NDVs for cancer therapy.