Canine distemper virus (CDV) is a highly contagious pathogen transmissible to a broad range of terrestrial and aquatic carnivores. Despite the availability of attenuated vaccines against CDV, the virus remains responsible for outbreaks of canine distemper (CD) with significant morbidity and mortality in domesticated and wild carnivores worldwide. CDV uses the signaling lymphocytic activation molecule (SLAM, or CD150) and nectin-4 (PVRL4) as entry receptors, well-known tumor-associated markers for several lymphadenomas and adenocarcinomas, which are also responsible for the lysis of tumor cells and apparent tumor regression. Thus, CDV vaccine strains have emerged as a promising platform of oncolytic viruses for use in animal cancer therapy. Recent advances have revealed that use of the CDV reverse genetic system (RGS) has helped increase the understanding of viral pathogenesis and explore the development of recombinant CDV vaccines. In addition, genetic engineering of CDV based on RGS approaches also has the potential of enhancing oncolytic activity and selectively targeting tumors. Here, we reviewed the host tropism and pathogenesis of CDV, and current development of recombinant CDV-based vaccines as well as their use as oncolytic viruses against cancers.

As the only widely used live lentiviral vaccine, the equine infectious anima virus (EIAV) attenuated vaccine was developed by in vitro passaging of a virulent strain for 121 generations. In our previous study, we observed that the attenuated vaccine was gradually selected under increased environmental pressure at the population level (termed a quasispecies). To further elucidate the potential correlation between viral quasispecies evolution and pathogenesis, a systematic study was performed by sequencing env using several methods. Some key mutations were identified within Env, and we observed that increased percentages of these mutations were accompanied by an increased passage number and attenuated virulence. Phylogenetic analysis revealed that env mutations related to the loss of virulence might have occurred evolutionarily. Among these mutations, deletion of amino acid 236 in the V4 region of Env resulted in the loss of one N-glycosylation site that was crucial for virulence. Notably, the 236-deleted sequence represented a “vaccine-specific” mutation that was also found in wild EIAV_LN40 strains based on single genome amplification (SGA) analysis. Therefore, our results suggest that the EIAV attenuated vaccine may originate from a branch of quasispecies of EIAV_LN40. Generally, the presented results may increase our understanding of the attenuation mechanism of the EIAV vaccine and provide more information about the evolution of other lentiviruses.

Channa asiatica is an economically valuable fish species and excellent model for studying hypoxic tolerance. However, the underlying genetic and molecular mechanisms are poorly understood. In this study, we assembled a high-quality C. asiatica genome (23 chromosomes, totaling 722 Mb) using a combination of Illumina short-read, PacBio long-read, and Hi-C sequencing. Repetitive elements accounted for 28.39%of the C. asiatica genome, and 23,949 protein-coding genes were predicted, with 96.63 % of these functionally annotated. Moreover, a comparative genomic analysis of 12 fish genomes showed that gene families associated with oxygen binding and transport were expanded in C. asiatica. In addition, transcriptome analysis revealed that multiple oxidative stress pathways were activated when C. asiatica was exposed to air. In conclusion, this study provided high-quality genome assembly and transcriptome data, both serving as critical resources for researching the genetic basis of hypoxic tolerance in C. asiatica.

Flammulina filiformis is the key industrial edible fungus that requires elevated CO₂ to promote the growth of long stipe and small pileus fruiting bodies. Heat shock transcription factors (HSFs) play vital roles in stress response and development regulation; yet the HSF gene family and its expression dynamics during fruiting body development in F. filiformis remain uncharacterized. This study aims to identify and characterize the HSF gene family in F. filiformis and to investigate their expression patterns during fruiting body development and in response to CO₂ treatments. In this study, 7 FfHSFs were identified, and their structures, sequence features, and phylogenetics were further analyzed. Expression patterns under CO₂ regulation were examined via qRT-PCR. The FfHSFs exhibited CDS lengths of 618–2298 bp, encoding 301–765 hydrophilic amino acids, with molecular weights ranging from 23.4 to 83.8 kDa and theoretical pI values between 4.75 and 9.15. All were predicted to be nuclear-localized. Cis-element analysis revealed motifs associated with growth regulation and stress responses such as low temperature, drought, and hypoxia. Phylogenetically, fungal HSFs were grouped into five clusters, with FfHSFs distributed across four. In this study, we examined the expression levels at four time points (0 h, 2 h, 12 h, and 36 h), under three different carbon dioxide concentrations (0.1%, 5%, and 20%) and in two types of tissues (pileus and stipe) for each six biological replicates. CO₂ treatments showed that 5% CO₂ significantly suppressed pileus expansion but not stipe elongation, while 20% CO₂ inhibited both. Under 20% CO₂ treatment, the pileus diameter decreased by approximately 40%, and simultaneously, the expression level of FfHSF1 decreased by about 70%. qRT-PCR indicated that FfHSF1 decreased with pileus expansion, whereas FfHSF4 increased. All FfHSFs were highly expressed in the stipe elongation zone. Elevated CO₂ down-regulated FfHSF1 in pileus and FfHSF6 in stipes. Based on these findings, it could be proposed that FfHSF1 and FfHSF6 might be candidate regulators in CO₂-mediated morphogenesis, providing insights into hormonal and environmental control of fruiting body development in F. filiformis.