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The cross-media water entry problem widely exists in fields such as ocean engineering and aerospace. The highly non-stationary characteristics of the cross-media water entry process significantly influence the structural strength and ballistic stability of vehicles. This paper selects air-dropped torpedoes, supercavitating vehicles, and high-speed projectiles as three typical types of cross-media vehicles for study. Based on their unique structural characteristics and typical water entry conditions, this paper focuses on the current status of their respective impact load and load reduction challenges, as well as water entry ballistic stability issues. At the research methodological level, this paper systematically reviews the progress of current research in three directions: theory, experiments, and numerical simulations, and introduces the application of artificial intelligence in solving cross-media problems. Finally, this paper looks forward to future development trends in cross-media water entry research, aiming to provide a reference for structural optimization design, motion stability control, and other related studies of cross-media vehicles.

To investigate the molecular mechanisms underlying muscle fiber development in different pig breeds and their impact on meat quality, this study collected the longissimus dorsi muscle of the indigenous Huainan pig and the commercial Large White pig at four developmental stages (0, 7, 14, and 21 days postnatal). Muscle fiber types were identified using myosin ATPase staining, while transcriptomics and non-targeted metabolomics were employed to analyze differences in gene expression and metabolite composition. The results showed that the Huainan pig had a higher proportion of oxidative muscle fibers, indicating superior aerobic metabolic capacity and meat quality. Transcriptome data identified 18 differentially expressed genes common to both pig breeds, including KLF4, NOS1, SH3KBP1, and TRARG1, which were upregulated in Huainan pigs to regulate muscle fiber type composition and meat quality by influencing mitochondrial function, nitric oxide synthesis, and glucose/lipid metabolism. Metabolomics analysis revealed significantly elevated levels of carnosine, citrulline, serine, and glycerol-3-phosphate in Huainan pigs, which are associated with metabolic pathways promoting muscle fiber transformation via enhancing energy supply, antioxidant capacity, and fatty acid oxidation. Notably, integrated transcriptome–metabolome analysis showed that oxidative metabolism genes (e.g., KLF4) and metabolites (e.g., citrulline) formed an AMPK-mediated ‘gene–metabolite’ loop in Huainan pigs, which synergistically promotes mitochondrial function and fiber differentiation. In summary, this study provides new insights into the molecular mechanisms underlying meat quality differences between pig breeds and offers a theoretical basis for the breeding and development of high-quality pork.

Background Porcine deltacoronavirus (PDCoV) is one of the emerging swine enteric coronaviruses (SECoVs), which has been widely prevalent in the North America and Asia. In addition to causing severe diarrhea in piglets, PDCoV also shows the potential to infect diverse host species, including calves, chickens, turkey poults, and humans. However, the clinical pathogenicity and genetic evolution of PDCoV is still not fully understood. Results Here, we recorded an outbreak of a novel recombinant PDCoV strain (CHN-HeN06-2022) in a large nursery fattening pig farm. Genomic analysis showed that the CHN-HeN06-2022 strain shared 98.3-98.7% sequence identities with the Chinese and American reference strains. To clarify the evolutionary relationships, phylogenetic analysis was performed using the PDCoV genome sequences available in the GenBank database. Based on genetic distance and geographical distribution, the phylogenetic tree clearly showed that all the PDCoV sequences could be divided into lineage 1 and lineage 2, which were further classified into sublineage 1.1 (Chinese strains), 1.2 (the North American strains), 2.1 (the Southeast Asian strains), and 2.2 (Chinese strains). Corresponding to the evolutionary tree, we found that, compared to lineage 1, lineage 2 strains usually contain a continuous 6-nt deletion in Nsp2 and a 9-nt deletion in Nsp 3, respectively. Furthermore, recombination analysis suggested that the CHN-HeN06-2022 occurred segments exchange crossed Nsp2 and Nsp3 region between sublineage 1.1 and sublineage 2.1. Combined with previously reported recombinant strains, the highest recombination frequency occurred in Nsp2 , Nsp3 , and S gene. Additionally, we identified a total of 14 amino acid sites under positive selection in spike protein, most of which are located in the regions related with the viral attachment, receptor binding, and membrane fusion. Conclusions Taken together, our studies provide novel insights into the genetic diversity and adaptive evolution of PDCoV. It would be helpful to the development of vaccine and potential antiviral agent.

The HN pig, indigenous to Henan Province, is distinguished by its reduced lean meat yield and slower growth rates relative to commercial foreign breeds. To address these limitations, three hybrid combinations were generated through the crossbreeding of Huainan sows with Yorkshire, Landrace, and Berkshire sires. In this study, extensive transcriptomic and metabolomic analyses of the LD muscle were carried out for the first time, and carcass and meat quality characteristics were compared between hybrid and HN pigs. Slaughter and muscle quality assessments revealed that the lean meat percentage of LH and YH was significantly lower than that of HN, with YH exhibiting the lowest intramuscular fat level, indicating that this breed possesses enhanced lean meat production efficiency. Transcriptomic profiling revealed markedly increased expression of SLIT2, CH25H, NR4A2, NR4A1, FOSB, CRABP2, GDF10, and MRAP2 in all three hybrid groups compared to HN. Gene Ontology enrichment analysis identified that the skeletal muscle cell differentiation (GO:0035914) and transforming growth factor beta receptor signaling pathway (GO:0007179) were exclusively enriched in the YH vs. HN comparison. Non-targeted metabolomic analysis identified 31, 36, and 12 DAMs in BH vs. HN, LH vs. HN, and YH vs. HN comparisons, with pyruvate metabolism being the sole pathway common to all groups. An integrated multi-omics analysis revealed significant correlations between phytosphingosine levels and DEGs across all three comparisons. In summary, these results indicate that crossbreeding substantially improves lean meat yield in HN pigs while providing novel molecular insights into the underlying genetic and metabolic mechanisms.

Fowl adenovirus serotype 4 (FAdV-4) is the main pathogen of hepatitis-hydropericardium syndrome (HHS), which brings huge economic losses to the poultry industry worldwide. Fiber-1 protein plays an important role in viral infection and pathogenesis by binding directly to cellular receptors of FAdV-4. In particular, the knob domain of fiber-1 protein has been reported to induce the production of neutralizing antibodies and arouse protection against the lethal challenge of chickens with FAdV-4. The fiber-1 knob (F1K) protein was expressed in a prokaryotic expression system and purified using Ni-NTA affinity chromatography. Monoclonal antibodies (mAbs) against FAdV-4 were generated by immunizing BALB/c mice with the purified F1K protein and screened using a series of immunoassays. Potential B cell epitopes on the knob domain of fiber-1 protein were mapped using enzyme-linked immunosorbent assay (ELISA) and dot-blot. Precious location and crucial amino acids of the identified epitopes were determined using peptide array scanning, truncations and alanine-scanning mutagenesis. The epitopes were analyzed and visualized on the knob trimer of FAdV-4 fiber-1 protein using the PyMOL software. Water-soluble recombinant fiber-1 knob (F1K) protein was obtained with the assistance of chaperone. Four monoclonal antibodies (5C10, 6F8, 8D8, and 8E8) against FAdV-4 were generated and characterized using indirect ELISA, Western blot, dot-blot, and immunological fluorescence assay (IFA). The mAbs were demonstrated to be from different hybridoma cell lines based on the sequences of the variable regions. Meanwhile, three distinct novel linear B-cell epitopes ( SDVGYLGLPPH , PHTRDNWYV , and VTTGPIPFSYQ ) on the knob domain of fiber-1 protein were identified and the key amino acid residues in the epitopes were determined. Structural analysis showed that the two adjacent epitopes SDVGYLGLPPH and PHTRDNWYV were exposed on the surface of the fiber-1 knob trimer, whereas the epitope VTTGPIPFSYQ was located inside of the spatial structure. This was the first identification of B-cell epitopes on the knob domain of fiber-1 protein and these findings provided a sound basis for the development of subunit vaccines, therapeutics, and diagnostic methods to control FAdV infections.

Background Porcine circovirus type 2 (PCV2) is the pathogen of porcine circovirus associated diseases (PCVAD) and one of the main pathogens in the global pig industry, which has brought huge economic losses to the pig industry. In recent years, there has been limited research on the prevalence of PCV2 in Henan Province. This study investigated the genotype and evolution of PCV2 in this area. Results We collected 117 clinical samples from different regions of Henan Province from 2015 to 2018. Here, we found that the PCV2 infection rate of PCV2 was 62.4%. Thirty-seven positive clinical samples were selected to amplify the complete genome of PCV2 and were sequenced. Based on the phylogenetic analysis of PCV2 ORF2 and complete genome, it was found that the 37 newly detected strains belonged to PCV2a (3 of 37), PCV2b (21 of 37) and PCV2d (13 of 37), indicating the predominant prevalence of PCV2b and PCV2d strains. In addition, we compared the amino acid sequences and found several amino acid mutation sites among different genotypes. Furthermore, the results of selective pressure analysis showed that there were 5 positive selection sites. Conclusions This study indicated the genetic diversity, molecular epidemiology and evolution of PCV2 genotypes in Henan Province during 2015–2018.

Outbreaks of hydropericardium hepatitis syndrome caused by fowl adenovirus serotype 4 (FAdV-4) with a novel genotype have been reported in China since 2015, with significant economic losses to the poultry industry. Fiber2 is one of the important structural proteins on FAdV-4 virions. In this study, the C-terminal knob domain of the FAdV-4 Fiber2 protein was expressed and purified, and its trimer structure (PDB ID: 7W83) was determined for the first time. A series of affinity peptides targeting the knob domain of the Fiber2 protein were designed and synthesized on the basis of the crystal structure using computer virtual screening technology. A total of eight peptides were screened using an immunoperoxidase monolayer assay and RT-qPCR, and they exhibited strong binding affinities to the knob domain of the FAdV-4 Fiber2 protein in a surface plasmon resonance assay. Treatment with peptide number 15 (P15; WWHEKE) at different concentrations (10, 25, and 50 μM) significantly reduced the expression level of the Fiber2 protein and the viral titer during FAdV-4 infection. P15 was found to be an optimal peptide with antiviral activity against FAdV-4 in vitro with no cytotoxic effect on LMH cells up to 200 μM. This study led to the identification of a class of affinity peptides designed using computer virtual screening technology that targeted the knob domain of the FAdV-4 Fiber2 protein and may be developed as a novel potential and effective antiviral strategy in the prevention and control of FAdV-4.

Sixty Duroc × (Landrace × Yorkshire) castrated male finishing pigs were randomly divided into negative control (NC) and gracilaria lemaneiformis polysaccharides (GLP) groups to study the effects of GLP on the fecal microbiota and fecal metabolites of fattening pigs. The NC group was fed a basic diet, and the GLP group was fed a basic diet supplemented with 0.1% GLP. The diversity of the species and the fecal metabolites were analyzed using 16S rDNA sequencing and metabolome sequencing, respectively. The serum immune and antioxidant indices were analyzed using the ELISA assay. The abundances of hazardous bacteria such as Proteobacteria at the phylum level and Shigella at the genus level were extremely significantly decreased (p < 0.01) and those of beneficial bacteria such as Firmicutes at the phylum level (p < 0.01), Clostridium at the genus level (p < 0.01), and Lactobacillus at the genus level (p < 0.05) were significantly increased in the GLP group compared with the NC group. A total of 41 differentially expressed metabolites were identified. The expression of anti-inflammatory and antioxidant active substances, such as methyl cinnamate, protopanaxatriol, and isovanillic acid, was elevated in the GLP group. The ELISA assay showed increased GSH-Px activity (p < 0.01), T-AOC (p < 0.01), IgG (p < 0.01), IgA (p < 0.05), and IgM (p < 0.05) in the GLP group. These results indicate that dietary GLP supplementation can improve the antioxidant ability, anti-inflammatory ability, and immune level of fattening pigs by regulating fecal flora and metabolites and could be used as a functional feed additive.

The Huainan pig (HN) is known for its impressive litter size and exquisite meat quality. However, it also exhibits certain drawbacks such as excessive fat deposition, a relatively low percentage of lean meat percentage, and a slower growth rate. Crossbreeding with lean-type breeds, such as Large White, Landrace, and Berkshire can enhance offspring traits, and increase genetic diversity. In this study we employed RNA-seq technology to identify differentially expressed genes (DEGs) in subcutaneous adipose tissue (SAT) samples from HN pigs and their crosses with multiple breeds (with three replicates per group). In the SAT of Huainan × Berkshire pigs (BH), Huainan × Yorkshire pigs (YH), and Huainan × Landrace pigs (LH), numerous key functional genes were identified, including , , , , , , , and . Functional enrichment analysis revealed that DEGs were primarily involved in several key pathways in BH, including the peroxisome proliferator-activated receptor (PPAR) signaling, metabolic pathways, arachidonic acid metabolism, and arginine/proline metabolism. Similarly, in LH, DEGs were associated with PPAR, cyclic adenosine monophosphate (cAMP) signaling, mitogen-activated protein kinase (MAPK), and the arginine/proline pathway. In contrast, the main pathways in YH were slightly different, including MAPK, fatty acid elongation, arginine/proline metabolism, and glycine/serine/threonine metabolism. Compared to HN, the differential genes in BH, LH, and YH showed a reduced fat deposition. However, in comparison, LH has a stronger subcutaneous fat deposition ability. Notably, LH exhibited a stronger tendency for subcutaneous fat deposition than the other two groups, while YH had the lowest fat deposition capacity. In conclusion, these findings offer valuable insights and provide a foundation for future research on the molecular mechanisms underlying fat deposition in pigs.

African swine fever virus (ASFV) causes a highly contagious and often lethal swine viral disease, and leads to tremendous economic losses to the swine industry. Unfortunately, there are no vaccines and effective antiviral agents available to prevent and control ASFV outbreaks. Therefore, it is necessary to develop simple and rapid strategies to monitor ASFV-infected pigs to restrain its spread. In the current study, ASFV capsid protein p72 was expressed along with its chaperone pB602L to form trimers in human embryonic kidney 293 (HEK293) cells. The p72 trimers were subsequently labeled with colloidal gold to develop a immunochromatographic strip. The strip showed high specificity to ASFV-positive serum and no cross-reactivity to other swine virus positive sera. Importantly, the strip showed a higher sensitivity of detecting ASFV antibodies in both positive standard serum and clinical serum samples than a commercial enzyme-linked immunosorbent assay (ELISA) kit. Taken together, these results demonstrate the strip as a reliable diagnostic tool against ASFV infection, which will be appropriate for application in prevention and control of ASFV. Key points • ASFV p72 trimers were successfully generated . • A colloidal gold strip was developed based on ASFV p72 trimers . • The strip is appropriate for detecting ASFV antibodies in the field .