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ABSTRACT: Unlike other poultry, parent pigeons produce “pigeon milk” in their crops to nurture their squabs, which is mainly controlled by prolactin (PRL). Exception for PRL, the pituitary gland may also release various other peptide and protein hormones. However, whether these hormones change during pigeon crop lactation and their potential physiological functions remain unclear. Here, to identify potential peptide or protein hormone genes that regulate crop lactation, we conducted transcriptome analysis of pigeon pituitary glands at 3 different breeding stages (the ceased stage—nonincubation and non-nurturing stage, the 11th d of the incubation, and the 1st d of the nurturing stage) using RNA sequencing (RNA-Seq). Our analysis identified a total of 15,191 mRNAs and screened out 297 differentially expressed genes (DEG), including PRL, VIP, etc. The expression abundance of PRL mRNA on the 1st d of the nurturing stage was respectively 4.93 and 3.62 folds higher when compared to the ceased stage and the 11th d of the incubation stage. Additionally, the expression abundance of VIP is higher in the 1st d of the nurturing stage than in the ceased stage. Protein–protein interaction (PPI) network and Molecular Complex Detection (MCODE) analysis identified several vital DEGs (e.g., GHRHR, VIP, etc.), being closely linked with hormone and enriched in neuropeptide signaling pathway and response to the hormone. Expression pattern analysis revealed that these DEGs exhibited 4 distinct expression patterns (profile 10, 16, 18, 19). Genes in profile 10 and 19 presented a trend with the highest expression level on 1st d of the nurturing stage, and functional enrichment analysis indicated that these genes are involved in neuropeptide hormone activity, receptor-ligand activity, and the extracellular matrix, etc. Taken together, being consistent with PRL, some genes encoding peptide and protein hormones (e.g., VIP) presented differentially expressed in different breeding stages. It suggests that these hormones may be involved in regulation of the crop lactation process or corresponding behavior in domestic pigeons. The results of this study help to gain new insights into the role of pituitary gland in regulating pigeon lactation.

Nickel (Ni) is the most important environmental pollution in the world. Ni has been confirmed to have multi-organ toxicology and carcinogenicity. Recently, Ni also can impair the male reproductive system, however, its precious mechanism still has not been clarified. The current work found that nickel chloride (NiCl2) induced histopathological lesions in testis. And, the Johnsen's score, seminiferous tubule diameter, and spermatogenic epithelium thickness were decreased in NiCl2-treated mice. The number of spermatogonium, primary spermatocyte, and round spermatid also were significantly reduced after Ni treatment. Next the potential molecular mechanism was measured. NiCl2 treatment elevated ROS production in the testis. Additionally, NiCl2 was found to induce apoptosis with features including up-regulation of Bax, cleaved-caspase-3, cleaved-caspase-8, caspase-9, and caspase-12, while down-regulation of Bcl-2 expression. In the meantime, the marker protein of DNA damage γ-H2AX was significantly increased in NiCl2-primed mice testis. To clarify effects of reactive oxygen species (ROS) in apoptosis and DNA damage induced by NiCl2, NiCl2 was used to co-treat antioxidant NAC (N-Acetyl-L-cysteine). NAC weakened ROS production induced by NiCl2, and played an inhibition role in apoptosis and DNA damage. Moreover, co-treatment using NiCl2 and NAC group also eliminated spermatogenesis disorders. In summary, research results reveal the relations of spermatogenesis disorder induced by NiCl2 with apoptosis and DNA damage mediated by ROS and apoptosis in the testis.

Nickel (Ni) is an essential common environmental contaminant, it is hazardous to male reproduction, but the precise mechanisms are still unknown. Blood-testis barrier (BTB), an important testicular structure consisting of connections between sertoli cells, is the target of reproductive toxicity caused by many environmental toxins. In this study, ultrastructure observation and BTB integrity assay results indicated that NiCl2 induced BTB damage. Meanwhile, BTB-related proteins including the tight junction (TJ), adhesion junction (AJ) and the gap junction (GJ) protein expression in mouse testes as well as in sertoli cells (TM4) were significantly decreased after NiCl2 treatment. Next, the antioxidant N-acetylcysteine (NAC) was co-treated with NiCl2 to study the function of oxidative stress in NiCl2-mediated BTB deterioration. The results showed that NAC attenuated testicular histopathological damage, and the expression of BTB-related proteins were markedly reversed by NAC co-treatment in vitro and vivo. Otherwise, NiCl2 activated the p38 MAPK signaling pathway. And, NAC co-treatment could significantly inhibit p38 activation induced by NiCl2 in TM4 cells. Furthermore, in order to confirm the role of the p38 MAPK signaling pathway in NiCl2-induced BTB impairment, a p38 inhibitor (SB203580) was co-treated with NiCl2 in TM4 cells, and p38 MAPK signaling inhibition significantly restored BTB damage induced by NiCl2 in TM4 cells. These results suggest that NiCl2 treatment destroys the BTB, in which the oxidative stress-mediated p38 MAPK signaling pathway plays a vital role.

Abstract Background It has been reported Interferon‐λ (IFN‐λ) has stronger antiviral effect than other interferons. IFN‐λ can induce antiviral interferon stimulated genes (ISGs) in epithelia to protect against virus. Pseudorabies virus (PRV) infection in pigs resulting in fatal encephalitis in newborn piglets, respiratory disorders in finishing pigs, reproductive disorders in sows and other symptoms. Objectives Since the effect of IFN‐λ on inhibiting PRV proliferation is still unknown. Inthis study, we investigate the relative contribution of porcine IFN‐λ3 toward controlling the infection of PRV in vitro. Our findings may provide a new insight for the prevention and treatment of PRV. Methods Therefore, the antiviral assay, western blot, qRT‐PCR and ELISA assay were used to investigating the contribution of IFN‐λ against PRV in PK‐15 cells. Results Here, we demonstrate that the replication of PRV in PK‐15 cells was inhibited after pre‐treatment with IFN‐λ3, and such inhibition was dose dependent. Overexpression of IFN‐λ3 receptor (IFNLR) also restricted virus titre in PK‐15 cells. In addition, IFN‐λ3 also increased the mRNA and protein expression of interferon‐stimulated genes 15 (ISG15), 2′‐5′‐oligoadenylate synthase 1 (OAS1), IFN‐inducible transmembrane 3 (IFITM3) and myxoma resistance protein 1 (Mx1) in PRV‐infected PK‐15 cells. Other than modulation ISGs, IFN‐λ specifically activated IFN‐γ mRNA expression not IFN‐α or IFN‐β. Conclusions IFN‐λ3 had antiviral activity against PRV and the upregulation of ISGs and IFN‐γ mRNA expression may be the mechanism of IFN‐λ3's antiviral activities. Thus, IFN‐λ3 has a decisive function that greatly limits PRV replication in PK‐15 cells. Our study explores the antiviral activity of IFN‐λ3 on PRV for the first time.

Nickel, as a widely polluted metal, has been shown nephrotoxicity. Ferroptosis is a new type of cell death driven by iron-dependent lipid peroxidation. Our study found that nickel chloride (NiCl2) induced ferroptosis in mouse kidney and TCMK-1 cells. The iron content was significantly increased in the kidney and TCMK-1 cells after NiCl2 treatment. Lipid peroxidation and MDA content were significantly increased, and GSH content and T-SOD activity were significantly decreased after exposure to NiCl2. Moreover, NiCl2 increased COX-2 protein levels, decreased SLC7A11 and GPX4 protein levels, and elevated Ptgs2 mRNA levels. Next, the mechanism of Ni-induced ferroptosis was investigated. The results showed that NiCl2 induced autophagy in TCMK-1 cells, which promoted ferroptosis induced by NiCl2. Furthermore, the data of autophagy activation or inhibition experiment showed that autophagy facilitated ferroptosis through the degradation of the iron regulation protein NCOA4 and FTH1. Otherwise, iron chelator DFOM treatment inhibited ferroptosis induced by NiCl2. Finally, ferroptosis inhibitor Fer-1 treatment significantly alleviated cytotoxicity induced by NiCl2. To sum up, our above results showed that ferroptosis is involved in NiCl2-induced nephrotoxicity, and NiCl2 induces autophagy-dependent ferritin degradation, releases iron ions, leads to iron overload, and induces ferroptosis. This study supplies a new theoretical foundation for the study of nickel and renal toxicity.

IntroductionThe pathogenesis of Vibrio mimicus infection in yellow catfish (Pelteobagrus fulvidraco) remains poorly understood, particularly regarding the impact of infection with the pathogen on primary target organs such as the skin and muscle.MethodsIn this study, we aim to analyze the pathological intricacies of the skin and muscle of yellow catfish after being infected with V. mimicus using a 1/10 LC50 seven-day post-infection model. Furthermore, we have utilized integrated bioinformatics to comprehensively elucidate the regulatory mechanisms and identify the key regulatory genes implicated in this phenomenon.ResultsOur histopathological examination revealed significant pathological changes in the skin and muscle, characterized by necrosis and inflammation. Moreover, tissue remodeling occurred, with perimysium degeneration and lesion invasion into the muscle along the endomysium, accompanied by a transformation of type I collagen into a mixture of type I and type III collagens in the perimysium and muscle bundles. Our eukaryotic transcriptomic and 4D label-free analyses demonstrated a predominantly immune pathway response in both the skin and muscle, with downregulation observed in several cell signaling pathways that focused on focal adhesion-dominated cell signaling pathways. The upregulated genes included interleukins (IL)-1 and -6, chemokines, and matrix metallopeptidases (mmp)-9 and -13, while several genes were significantly downregulated, including col1a and col1a1a. Further analysis revealed that these pathways were differentially regulated, with mmp-9 and mmp-13 acting as the potential core regulators of cytokine and tissue remodeling pathways. Upregulation of NF-κB1 and FOSL-1 induced by IL-17C and Nox 1/2-based NADPH oxidase may have held matrix metallopeptidase and cytokine-related genes. Also, we confirmed these relevant regulatory pathways by qPCR and ELISA in expanded samples.DiscussionOur findings unequivocally illustrate the occurrence of a cytokine storm and tissue remodeling, mediated by interleukins, chemokines, and MMPs, in the surface of yellow catfish infected with V. mimicus. Additionally, we unveil the potential bidirectional regulatory role of MMP-9 and MMP-13. These results provide novel perspectives on the intricate immune response to V. mimicus infection in yellow catfish and highlight potential targets for developing therapies.

Abstract Pseudorabies virus (PRV), also known as suid Alphaherpesvirus 1 (SuHV-1), which is one of the most devastating infectious pathogen of swine industry worldwide. Vaccination is the safest and most effective PRV prevention and control strategy. B cell receptor (BCR) is membrane-bound immunoglobulin located on the surface of B cells capable of specifically binding foreign antigens, which is one of the most important molecules regulating the proliferation and function of B cells. Here, to assess the molecular diversity of BCR H-CDR3 repertoire after different PRV strains infection, we detected the IGHV, IGHD, IGHJ genes usage and CDR3 sequence changes of mice spleen with PRV vaccine strain (Bartha-K61), variant strain (XJ) and mock infection by high-throughput sequencing. We found that PRV-infected groups shared partial BCR sequences, which are most likely to be PRV-specific BCR candidates. However, there were still differences in the IGHV genes usage as well as the combined usage of IGHV and IGHJ genes between the Bartha-K61 strain and XJ strain infection groups. In addition, the CDR3 sequences exhibited large differences in the types and lengths in PRV infection groups. Our study contributes to a better understanding of the host adaptive immune response to PRV infection and provides a theoretical basis for further research on novel and efficient PRV vaccines in the future.

Abstract JEV is one of the zoonotic pathogens that cause serious diseases in humans. JEV infection can cause abortion, mummified foetus and stillbirth in sows, orchitis and semen quality decline in boars, causing huge economic losses to pig industry. In order to investigate the epidemiology of JEV in pigs in Sichuan province, a rapid and efficient fluorescent Reverse transcription recombinase-aided amplification (RT-RAA) detection method was established. Aborted fetuses and testicular swollen boar samples were detected by RT-RAA in pigs in the mountain areas around Sichuan Basin, and the detection rate of JEV was 6.49%. The positive samples were identified as JEV GI strain and GIIIstrain by sequencing analysis. We analyzed the whole gene sequence of a positive sample for the GI virus. The Envelope Protein (E protein) phylogenetic tree analysis was far related to the Chinese vaccine strain SA14-14-2, and was most closely related to the JEV GI strains SH17M-07 and SD0810 isolated from China. The results showed that we established an efficient, accurate and sensitive method for clinical detection of JEV, and JEV GI strains were prevalent in Sichuan area. It provides reference for the prevention and control of JEV in Sichuan.

Abstract Background Hepatitis E virus (HEV) is an important zoonotic pathogen, Genotypes 3 and 4 are the main zoonotic genotype. Due to the lack of mature and effective culture cell lines, researches on genotype IV swine HEV (SHEV‐4) infection and pathogenic mechanism have been carried out in pigs, gerbils and non‐human primate models. Objectives The aim of this study was to establish a rat infection model by intra‐peritoneal infection with SHEV‐4, which provided a new research idea and scientific basis for further revealing the mechanism of HEV infection and preventing HEV infection. Methods SHEV‐4 virus was administered intra‐peritoneally to 6‐ to 8‐week‐old mice to observe the serological changes and virus release. Results According to the results of the rat serum HEV IgG, ALT and AST levels, swine HEV, minus‐strand HEV RNA can infect Sprague–Dawley rats across species, and there are no obvious clinical symptoms after infection. HEV RNA was detected in most tissues and organs after infection, but the viral load was low. The liver had pathological changes of chronic hepatitis. Conclusions We found that the rat model of porcine HEV infection is a small animal model suitable for the study of HEV infection.

Abstract Background Porcine deltacoronavirus (PDCoV) is a new pathogenic porcine intestinal coronavirus, which has appeared in many countries since 2012. PDCoV disease caused acute diarrhea, vomiting, dehydration and death in piglets, resulted in significant economic loss to the pig industry. However, there is no commercially available vaccine for PDCoV. In this study, we constructed recombinant pseudorabies virus (rPRVXJ-delgE/gI/TK-S) expressing PDCoV spike (S) protein and evaluated its safety and immunogenicity in mice. Results The recombinant strain rPRVXJ-delgE/gI/TK-S obtained by CRISPR/Cas gE gene editing technology and homologous recombination technology has genetic stability in baby hamster syrian kidney-21 (BHK-21) cells and is safe to mice. After immunizing mice with rPRVXJ-delgE/gI/TK-S, the expression levels of IFN-γ and IL-4 in peripheral blood of mice were up-regulated, the proliferation of spleen-specific T lymphocytes and the percentage of CD4+ and CD8+ lymphocytes in mice spleen was increased. rPRVXJ-delgE/gI/TK-S showed good immunogenicity for mice. On the seventh day after booster immunity, PRV gB and PDCoV S specific antibodies were detected in mice, and the antibody level continued to increase, and the neutralizing antibody level reached the maximum at 28 days post- immunization (dpi). The recombinant strain can protect mice with 100% from the challenge of virulent strain (PRV XJ) and accelerate the detoxification of PDCoV in mice. Conclusion The recombinant rPRVXJ-delgE/gI/TK-S strain is safe and effective with strong immunogenicity and is expected to be a candidate vaccine against PDCoV and PRV.

Koi sleepy disease (KSD) is a high mortality and infection viral disease caused by carp edema virus (CEV), which was a serious threat to aquaculture of common carp and export trade of Koi worldwide. Asymptomatic infection is an important cause of the difficulty in preventing KSD and its worldwide spread, because asymptomatic infection can be activated under appropriate condition. However, the understanding of the molecular correlates of these infections is still unknown. The purpose of this study was to compare the pathology change, enzyme activity, immunoglobulin activity, host and viral gene expression differences in acutely infected and cohabiting asymptomatic Koi infected with CEV. Healthy Koi were used as a control. The gross pathology, histopathology and ultrastructural pathology showed the difference and characteristics damage to the tissues of Koi under different infection conditions. Periodic Acid-Schiff stain (PAS), enzyme activity and immunoglobulin activity revealed changes in the immune response of gill tissue between acutely infected, asymptomatic infected and healthy Koi. A total of 111 and 2484 upregulated genes and 257 and 4940 downregulated genes were founded in healthy Koi vs asymptomatic infected Koi and healthy Koi vs acutely infected Koi, respectively. Additionally, 878 upregulated genes and 1089 downregulated genes were identified in asymptomatic vs. acutely infected Koi. Immune gene categories and their corresponding genes in different comparison groups were revealed. A total of 3, 59 and 28 immune-related genes were identified in the group of healthy Koi vs asymptomatic infected Koi, healthy Koi vs acutely infected Koi and asymptomatic infected Koi vs acutely infected Koi, respectively. Nineteen immune-related genes have the same expression manner both in healthy Koi vs acutely infected Koi and asymptomatic Koi vs acutely infected Koi, while 9 immune-related genes were differentially expressed only in asymptomatic Koi vs acutely infected Koi, which may play a role in viral reactivation. In addition, 8 differentially expressed genes (DEGs) were validated by quantitative reverse transcription PCR (RT-qPCR), and the results were consistent with the RNA-Seq results. In conclusion, the data obtained in this study provide new evidence for further elucidating CEV-host interactions and the CEV infection mechanism and will facilitate the implementation of integrated strategies for controlling CEV infection and spread.

IntroductionSurveillance of the Seneca Valley virus (SVV) shows a disproportionately higher incidence on Chinese pig farms. Currently, there are no vaccines or drugs to treat SVV infection effectively and effective treatment options are urgently needed.MethodsIn this study, we evaluated the antiviral activity of the following medium-chain fatty acids (MCFAs) or triglycerides (MCTs) against SVV: caprylic acid, caprylic monoglyceride, capric monoglyceride, and monolaurin.ResultsIn vitro experiments showed that monolaurin inhibited viral replication by up to 80%, while in vivo studies showed that monolaurin reduced clinical manifestations, viral load, and organ damage in SVV-infected piglets. Monolaurin significantly reduced the release of inflammatory cytokines and promoted the release of interferon-γ, which enhanced the viral clearance activity of this type of MCFA.DiscussionTherefore, monolaurin is a potentially effective candidate for the treatment of SVV infection in pigs.

Abstract Background Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically devastating diseases affecting the swine industry globally. Evaluation of antibody responses and neutralizing antibody titers is the most effective method for vaccine evaluation. In this study, the B cell line epitopes of PRRSV M protein were predicted, and two peptide ELISA assays were established (M-A110-129 ELISA, M-A148-174 ELISA) to detect antibodies against PRRSV M protein. Field serum samples collected from pig farms were used to validate the peptide ELISA and compare it with an indirect immunofluorescence assay. Results The sensitivity and specificity of M-A110-129 ELISA and M-A148-174 ELISA were (111/125) 88.80%, (69/70) 98.57% and (122/125) 97.60%, (70/70) 100%, relative to indirect immunofluorescence assay. This peptide ELISA could detect antibodies against different genotypes of PRRSV including type 1 PRRSV, classical PRRSV, HP-PRRSV, and NADC30 like PRRSV, but not antibodies against other common swine viruses. The results of ROC analysis showed that the area under the curve (AUC) of the M-A110-129 ELISA and M-A148-174 ELISA were 0.967 and 0.996, respectively. Compared the concordance of results using two peptide ELISA assays, the IDEXX PRRSV X3 Ab ELISA and a virus neutralization test, were assessed using a series of 147 sera from pigs vaccinated with the NADC30-like PRRSV inactivated vaccine. The M-A148-174 ELISA had the best consistency, with a Cohen’s kappa coefficient of 0.8772. The concordance rates of the Hipra PRRSV ELISA kit, M-A110-129 ELISA and M-A148-174 ELISA in the field seropositive detection results were 91.08, 86.32 and 95.35%, relative to indirect immunofluorescence assay. Conclusions In summary, compared with M-A110-129 ELISA, the PRRSV M-A148-174 ELISA is of value for detecting antibodies against PRRSV and the evaluation of the NADC30-like PRRSV inactivated vaccine, but the advantage is insufficient in serological early diagnosis.

Abstract GETV, an arbo-borne zoonotic virus of the genus Alphavirus, which causes diarrhea and reproduction disorders in swine, lead to serious economic losses to the swine industry in China. At present, the existing methods for GETV detection are time-consuming and low sensitivity, so, a rapid, accurate and sensitive GETV detection method is urgently needed. In this study, a fluorescent reverse transcription recombinase-assisted amplification method (RT-RAA) was successfully established for the rapid detection of GETV. The sensitivity of this method to GETV was 8 copies/reaction and 20 TCID50/reaction. No cross-reaction with other viruses. A total of 118 samples were prepared for GETV detection using fluorescent RT-RAA and SYBR Green I RT-qPCR, the coincidence rate of the two methods was 100%. The results suggest that the RT-RAA method is rapid, sensitive and specific for GETV detection and can be applied in the clinical.

Streptococcus dysgalactiae has emerged as an important pathogen that affects fish and mammals. Recently, channel catfish cultured in Sichuan, suffered an infectious disease characterized by neurological symptoms and many partial ulcers throughout the body, disease reaching 30 % cumulative mortality. Thus, the purpose of this study is to describe the characteristics of the disease, analyze disease factors, and clarify its etiology. The histopathologic analysis revealed that granuloma was found in liver, spleen, head and posterior kidney tissues. A Gram-positive, chain-forming coccus was isolated from the diseased fish and was identified as S. dysgalactiae by biochemical analysis, 16 S rDNA, immunogenic secreted protein (isp) gene sequence, MALDI-TOF-MS analysis, and Average Nucleotide Identity (ANI) analysis. The pathogenicity of the isolated strain was confirmed by an experimental analysis, and its LD50 was 7.63 × 106 CFU/ml. The whole genome size of the isolated strain was 2.22 Mb and the G+C content was 39.7 % (GenBank accession number: CP_095081). There were 2315 predicted protein coding sequences (CDSs), including 18 rRNA, 67 tRNA, and 41 sRNA genes. A total of 2649 Gene Ontology (GO) terms were assigned to 1414 (61.08 %) genes, and a total of 157 virulence genes and 120 antibiotic resistance genes were predicted. The drug sensitivity results showed that the isolated strain was resistant to fluoroquinolone antibiotic, tetracycline antibiotic, macrolide antibiotic, and aminoglycoside antibiotic. To our knowledge, this is the first report on S. dysgalactiae as a virulent pathogen in the channel catfish in China, and the findings of this study can increase the current literature on the range of hosts affected by S. dysgalactiae.

Porcine rotavirus type A (PoRVA) is the main cause of dehydration and diarrhea in piglets, which has a great impact on the development of the pig industry worldwide. A rapid, accurate and sensitive detection method is conducive to the monitoring, control, and removal of PoRVA. In this study, a PoRVA real-time fluorescent reverse transcription recombinase-aided amplification (RT-RAA) assay was developed. Based on the PoRVA VP6 gene, specific primers and probes were designed and synthesized. The sensitivity of RT-RAA and TaqMan probe-based RT-qPCR was 7 copies per reaction and 5 copies per reaction, respectively. The sensitivity of the RT-RAA method was close to TaqMan probe-based RT-qPCR. The detection results of RT-RAA and TaqMan probe-based quantitative real-time RT-PCR methods were completely consistent in 241 clinical samples. Therefore, we successfully established a rapid and specific RT-RAA diagnostic method for PoRVA.

Sturgeon (Acipenseriformes) and catfish (Siluriformes) are two of the most famous special economic animals, accounting for 1.3 million tons of production in China. Enteric redmouth disease caused by Yersinia ruckeri is common in these two fishes. This study carried out a surveillance of ERM from April 2016 to August 2018 in the Sichuan province. The genotyping and the distribution of antibiotic resistance profiles (ARPs) and genes (ARGs) of Y. ruckeri were established in this study. The results showed that Y. ruckeri was a common pathogen in catfish and sturgeon, accounting for 25.56 % and 17.65 %, respectively. Sixteen strains were obtained and were clustered into 5 genotypes which has a fish-specific characteristic. Y. ruckeri had appeared resistance to 14 of the 20 antibiotics, and 39 antibiotic resistance genes were detected positively from 95 specific primers. Also, there were significant differences in antibiotic resistance profiles among different strains. The sturgeon-derived Y. ruckeri had higher detection rates of aac(6)-Ib(aka aacA4)-1, aac(6)-Ib(aka aacA4)-2, aac(6)-Ib(aka aacA4)-3, fox5 and acrF, and higher resistance rates to ampicillin, ciprofloxacin, levofloxacin, kanamycin, and neomycin compared with the catfish-derived strains. Our results indicated that Y. ruckeri might become an important pathogen in catfish and sturgeon culture in Sichuan, and there were different subspecies of variation. Besides, Y. ruckeri has enriched many antibiotic resistances that may help evolve into super bacteria.

IFN is the most potent antiviral cytokine required for the innate and adaptive immune responses, and its expression can help the host defend against viral infection. Arteriviruses have evolved strategies to antagonize the host cell’s innate immune responses, interfering with IFN expression by interfering with RIG, blocking PRR, obstructing IRF-3/7, NF-κB, and degrading STAT1 signaling pathways, thereby assisting viral immune evasion. Arteriviruses infect immune cells and may result in persistence in infected hosts. In this article, we reviewed the strategies used by Arteriviruses to antagonize IFN production and thwart IFN-activated antiviral signaling, mainly including structural and nonstructural proteins of Arteriviruses encoding IFN antagonists directly or indirectly to disrupt innate immunity. This review will certainly provide a better insight into the pathogenesis of the arthritis virus and provide a theoretical basis for developing more efficient vaccines.

Seneca Valley virus (SVV), a non-enveloped positive single-stranded virus can cause vesicular disease in swine. However, the mechanisms by which SVV activates an innate immune response remain unknown. Mitofusin-2 (MFN2), a mitochondria-shaping protein regulating mitochondrial fusion and fission, plays a crucial role in innate immune responses. But, the roles of Mfn2 in SVV infection have not been elucidated. Here, we show that SVV inhibited Mfn2 expression and NLRP3 inflammasome, activating RIG-I/IRF7 signaling pathway to increase IFN-λ3 expression. Overexpression of Mfn2 inhibited RIG-I/IRF7 signaling pathway, thus decreasing IFN-λ3 expression and promoting SVV replication. Interestingly, overexpression of Mfn2 also activated NLRP3 inflammasome but did not inhibit SVV proliferation. That may mean the RIG-I/IRF7 signaling pathway plays a more important role in SVV proliferation in PK-15 cells. This study could provide important insights into the modulation of host metabolism during SVV infection and provide a strong theoretical basis for a better understanding of the pathogenic mechanism and immune activation mechanism of SVV.

Herpesviruses belong to large double-stranded DNA viruses. They are under a wide range of hosts and establish lifelong infection, which creates a burden on human health and animal health. Innate immunity is the host’s innate defense ability. Activating the innate immune signaling pathway and producing type I interferon is the host’s first line of defense against infectious pathogens. Emerging evidence indicates that the cGAS-STING signaling pathway plays an important role in the innate immunity in response to herpesvirus infections. In parallel, because of the constant selective pressure imposed by host immunity, herpesvirus also evolves to target the cGAS-STING signaling pathway to inhibit or escape the innate immune responses. In the current review, we insight on the classical cGAS-STING signaling pathway. We describe the activation of cGAS-STING signaling pathway during herpesvirus infections and strategies of herpesvirus targeting this pathway to evade host antiviral response. Furthermore, we outline the immunotherapy boosting cGAS-STING signaling pathway.

Streptococcus iniae is a zoonotic pathogen, which seriously threatens aquaculture and human health worldwide. Antibiotics are the preferred way to treat S. iniae infection. However, the unreasonable use of antibiotics leads to the enhancement of bacterial resistance, which is not conducive to the prevention and treatment of this disease. Therefore, it is urgent to find new efficient and environmentally friendly antibacterial agents to replace traditional antibiotics. In this study, the antibacterial activity and potential mechanism of thymol against S. iniae were evaluated by electron microscopy, lactate dehydrogenase, DNA and protein leakage and transcriptomic analysis. Thymol exhibited potent antibacterial activity against S. iniae in vitro, and the MIC and MBC were 128 and 256μg/mL, respectively. SEM and TEM images showed that the cell membrane and cell wall were damaged, and the cells were abnormally enlarged and divided. 2MIC thymol disrupted the integrity of cell walls and membranes, resulting in the release of intracellular macromolecules including nucleotides, proteins and inorganic ions. The results of transcriptomic analysis indicated that thymol interfered with energy metabolism and membrane transport, affected DNA replication, repair and transcription in S. iniae. In vivo studies showed that thymol had a protective effect on experimental S. iniae infection in channel catfish. It could reduce the cumulative mortality of channel catfish and the number of S. iniae colonization in tissues, and increase the activities of non-specific immune enzymes in serum, including catalase, superoxide dismutase, lysozyme and acid phosphatase. Taken together, these findings suggested that thymol may be a candidate plant agent to replace traditional antibiotics for the prevention and treatment of S. iniae infection.

Developing quorum-sensing (QS) based anti-infection drugs is one of the most powerful strategies to combat multidrug-resistant bacteria. Paeonol has been proven to attenuate the QS-controlled virulence factors of P. aeruginosa by down-regulating the transcription of QS signal molecules. This research aimed to assess the anti-virulence activity and mechanism of paeonol against P. aeruginosa infection in vitro and in vivo. In this study, paeonol was found to reduce the adhesion and invasion of P.aeruginosa to macrophages and resist the cytotoxicity induced by P.aeruginosa. Paeonol reduced the expression of virulence factors of P.aeruginosa by inhibiting QS, thereby reducing the LDH release and damage of P.aeruginosa-infected macrophages. Paeonol can inhibit bacterial virulence and enhance the ability of macrophages to clear P.aeruginosa. In addition, paeonol exerts anti-inflammatory activity by reducing the expression of inflammatory cytokines and increasing the production of anti-inflammatory cytokines. Paeonol treatment significantly inhibited the activation of TLR4/MyD88/NF-κB signaling pathway and decreased the inflammation response of P. aeruginosa-infected macrophages. Paeonol also significantly reduced the ability of P.aeruginosa to infect mice and reduced the inflammatory response. These data suggest that paeonol can inhibit the virulence of P.aeruginosa and decrease the inflammation response in P.aeruginosa-infected macrophages and mice, which can decrease the damage induced by P.aeruginosa infection and enhance the ability of macrophages to clear bacteria. This study supports the further development of new potential anti-infective drugs based on inhibition of QS and virulence factors.

Getah virus (GETV) is a zoonotic arbovirus that can cause infection in many animals. It can cause pyrexia and reproductive losses in animals. The objective of the study was to explore the effects of GETV on male reproductive ability. Male mice were injected with 100 × TCID50/0.1 ml in a volume of 100-μL GETV in their hindquarter muscle, resulting in decreased semen quality and testicular histopathological changes, and the virus was detected in the testes. At 0.5 dpi (day post-infection), male mice showed decreased sperm density, motility, and decreased serum testosterone concentration, an increased sperm malformation rate, vacuoles in spermatogonial cells/spermatocytes in spermatogenic tubules, and the highest virus copies in testis. At 2 dpi, the sperm density and motility reached the lowest value of 3.99 × 106/ml and 62.03%, and the malformation rate reached 43.67%. At 28 dpi, the sperm indexes of the experimental group gradually approached that of the control group, but there were still significant differences. Since then, histopathological changes have worsened, with the most severe histopathological changes at 7 dpi and gradual recovery. Up to 14 dpi, the virus was detected by qRT-PCR and immunohistochemistry, which showed that the virus was only present in the testicular interstitium. GETV infection can rapidly enter the testis of mice and reduce the semen quality of mice, which needs to be paid attention to in the prevention and control of GETV.

Porcine reproductive and respiratory syndrome (PRRS) and pseudorabies (PR) are highly infectious swine diseases and cause significant financial loss in China. The respiratory system and reproductive system are the main target systems. Previous studies showed that the existing PR virus (PRV) and PRRS virus (PRRSV) commercial vaccines could not provide complete protection against PRV variant strains and NADC30-like PRRSV strains in China. In this study, the PRV variant strain XJ and NADC30-like PRRSV strain CHSCDJY-2019 are used as the parent for constructing a recombinant pseudorabies virus (rPRV)-NC56 with gE/gI/TK gene deletion and co-expressing NADC30-like PRRSV GP5 and M protein. The rPRV-NC56 proliferated stably in BHK-21 cells, and it could stably express GP5 and M protein. Due to the introduction of the self-cleaving 2A peptide, GP5 and M protein were able to express independently and form virus-like particles (VLPs) of PRRSV in rPRV-NC56-infected BHK-21 cells. The rPRV-NC56 is safe for use in mice; it can colonize and express the target protein in mouse lungs for a long time. Vaccination with rPRV-NC56 induces PRV and NADC30-like PRRSV specific humoral and cellular immune responses in mice, and protects 100% of mice from virulent PRV XJ strain. Furthermore, the virus-neutralizing antibody (VNA) elicited by rPRV-NC56 showed significantly lower titer against SCNJ-2016 (HP-PRRSV) than that against CHSCDJY-2019 (NADC30-like PRRSV). Thus, rPRV-NC56 appears to be a promising candidate vaccine against NADC30-like PRRSV and PRV for the control and eradication of the variant PRV and NADC30-like PRRSV.

Senecavirus A (SVA) is a new type of virus related to swine vesicular disease, which results in enormous economic losses worldwide. At present, the host transcriptional responses to SVA infection, host-SVA interactions, and the mechanism of SVA in innate immune modulation are not well understood. This study explores the gene expression profiles of PK-15 cells at 0, 6, 12, 18, 24, 36 h SVA post-infection by RNA sequencing. Our analysis identified 61, 510, 1,584, 2,460, and 2,359 differentially expressed genes (DEGs) in the comparison groups S6 vs. Control, S12 vs. Control, S18 vs. Control, S24 vs. Control, S36 vs. Control, respectively. The reproducibility and repeatability of the results were validated by RT-qPCR, and all DEGs exhibited expression patterns consistent with the RNA-seq results. According to GO enrichment analysis and KEGG pathway analysis of DEGs in different periods after SVA infection, we found that SVA infection significantly modified the host cell gene-expression patterns and the host cells responded in highly specific manners, including response to signal reception and transmission, external biotic stimulus, response to the virus and host immune defense response. Notably, we observed the specific induction of type III interferon IFN-λ1 and IFN-λ3, which indicated that type III interferon plays an important antiviral function in PK-15 cells. Furthermore, our results showed that SVA might be recognized by RIG-I/MDA-5 receptors first after infecting PK-15 cells and then activates downstream IRF7-mediated signaling pathways, causing an increase in the expression of type III interferon. This study could provide important insights into the modulation of host metabolism during SVA infection and provide a strong theoretical basis for a better understanding of the pathogenic mechanism and immune escape mechanism of SVA.

Copper (Cu) is a necessary micronutrient at lower concentration, while excessive Cu exposure or Cu homeostasis disorders can lead to toxicity. The mechanism of male reproductive toxicity induced by Cu is still unknown. This study aims to investigate whether autophagy plays an important role in copper-induced spermatogenesis disorder in vivo and vitro. The present study showed that copper sulfate (CuSO4) might significantly promote autophagy level in the testis and mouse-derived spermatogonia cell line GC-1 spg cells. Concurrently, CuSO4 could induce autophagy via AMPK-mTOR pathway that downregulated p-mTOR/mTOR and subsequently upregulated p-AMPKα/AMPKα as well as p-ULK1/ULK1. In the meanwhile, CuSO4 treatment could also increase expression levels of the autophagy-related proteins. Then, the role of oxidative stress in CuSO4-induced autophagy was investigated. The findings demonstrated that oxidative stress inhibitor (NAC) attenuated CuSO4-induced autophagy in vivo and vitro, reversing the activation for AMPK-mTOR pathway. Additionally, the study also investigated how autophagy worked under the spermatogenesis disorder induced by CuSO4. Inhibition of autophagy could decrease cell viability, and enhance the ROS accumulation and apoptosis in the GC-1 cells, meanwhile, the spermatogenesis disorder, oxidative stress and histopathological changes were increased in the testis. Furthermore, co-treatment with the apoptosis inhibitor (Z-VAD-FMK) could decrease the spermatogenesis disorder but not influence autophagy. Besides, the crosslink between autophagy and ferroptosis were also measured, the data showed that inhibition of autophagy could suppress CuSO4-induced ferroptosis in in vivo and vitro. Altogether, abovementioned results indicated that CuSO4 induced autophagy via oxidative stress-dependent AMPK-mTOR pathway in the GC-1 cells and testis, and autophagy activation possibly led to the generation of protection mechanism through oxidative damage and apoptosis inhibition, however, autophagy also aggravate CuSO4 toxicology through promoting ferroptosis. Overall, autophagy plays a positive role for attenuating CuSO4-induced testicular damage and spermatogenesis disorder. Our study provides a possible targeted therapy for Cu overload-induced reproduction toxicology.

Multi-drug-resistant Klebsiella pneumoniae (MDR K. pneumonia) is increasingly being reported with corresponding increase in morbidity and mortality all over the world. However, limited information is available concerning MDR K. pneumonia in giant pandas. The objective of this study was to grasp the drug resistance profile of MDR K. pneumonia isolated from giant pandas. A total of 182 K. pneumoniae isolates were collected from fresh feces of 94 captive giant pandas of different ages and sex and separated by season. We performed a standard disk diffusion antimicrobial susceptibility test with the isolates and further evaluated the antibiotic resistance genes (ARGs) of multi-drug-resistant strains by high-throughput quantitative PCR. In addition, we then analyzed mobile genetic elements (MGEs), integron gene cassettes, and the multi-locus sequence typing of multi-drug-resistant strains by PCR. Antimicrobial susceptibility testing results demonstrated that a total of 30 (16.5%) K. pneumoniae isolates showed multiple drug resistances. The thirty MDR K. pneumonia isolates were mainly resistant to amoxicillin (100.0%), doxycycline (86.7%), chloramphenicol (60.0%), compound trimethoprim (60.0%) and trimethoprim (56.7%). Fifty different types of antibiotic resistance genes were found, which included a total of 671 antibiotic resistance genes, in the 30 multi-drug-resistant isolates. The top ten resistance genes were: vanTC-02, aacC, blaCTX-M-04, blaSHV-01, blaSHV-02, ampC-04, blaOXY, tetD, blaTEM and tetA-02. Thirteen mobile genetic elements were detected, of which IS26 (96.67%) and intI1 (96.67%) had the highest frequency. The thirty MDR K. pneumonia isolates were negative for the traA, traF, tnsA, IS1133, ISpa7, ISkpn6, intI2 and intI3 genes. Moreover, a further investigation of integrons revealed that two types of specific gene cassettes (dfrA12 + orfF + aadA2 and dfrA12 + orfF) were identified in class 1 integrons. Multi-locus sequence typing results showed that 22 STs in the thirty MDR K. pneumonia isolates were identified, the main type was ST37 (5/30). Our results illustrate that effective surveillance and strict biosecurity strategies should be taken to prevent the spread of multi-drug-resistant bacteria, and monitor the emergence of mobile genetic elements and integrons.

Porcine deltacoronavirus (PDCoV) is an emerging porcine intestinal coronavirus in recent years, which mainly causes different degrees of vomiting and diarrhea in piglets and has caused great harm to the swine husbandry worldwide since its report. Selenium is an essential trace element for organisms and has been demonstrated to have antiviral effects. In this study, pig kidney epithelial (LLC-PK) cells were used to study the antiviral activity of selenomethionine (Se-Met) (2, 4, 8, and 16 μM) against PDCoV by detecting the replication of the virus, the expression of the mitochondrial antiviral signal protein (MAVS) protein, and the phosphorylation of interferon regulatory factor-3 (IRF-3), IFN-α, and IFN-β, and the changes in glutathione content, glutathione peroxidase, superoxide dismutase activity, and hydrogen peroxide content in the cells. The results showed that Se-Met at higher than physiological concentrations (16 μM) could significantly inhibit the replication of PDCoV in LLC-PK cells and enhance the expression of MAVS protein and the phosphorylation of IRF-3. In addition, Se-Met also improved the intracellular production of IFNα/β and antioxidant capacity with increasing doses. These data suggest that the availability of selenium through selenomethionine supports the antiviral response in porcine kidney cells, and the specific mechanism is attributed to the improved cellular antioxidant capacity and activation of the MAVS pathway by Se-Met.

Macrophages are crucial components of the immune system and play a critical role in the initial defense against pathogens. They are highly heterogeneous and plastic and can be polarized into classically activated macrophages (M1) or selectively activated macrophages (M2) in response to local microenvironments. Macrophage polarization involves the regulation of multiple signaling pathways and transcription factors. Here, we focused on the origin of macrophages, the phenotype and polarization of macrophages, as well as the signaling pathways associated with macrophage polarization. We also highlighted the role of macrophage polarization in lung diseases. We intend to enhance the understanding of the functions and immunomodulatory features of macrophages. Based on our review, we believe that targeting macrophage phenotypes is a viable and promising strategy for treating lung diseases.

Since the first report of PCV3 virus infection in 2016, it has been linked to multisystemic inflammation, reproductive failure, cardiac pathology, and clinical indications resembling porcine dermatitis and nephropathy syndrome (PDNS). However, the pathogenesis and clinical significance of PCV3 is still unclear. In this study, a PCV3 infection model was created using SPF pigs, and histopathology and fluorescence quantitative PCR were utilized to examine PCV3’s pathogenicity. Reductions in body weight gain and fever were observed during this study. However, other clinical signs such as Dermatitis and Nephropathy Syndrome were not observed through the study. Viremia was detected in the PCV3-inoculated group from 17 days post-inoculation (p.i.) until the end of the study. Nasal shedding was detected from 21 to 35 dpi and fecal shedding was detected during 25–33 days and 39 days, respectively. Gross lesions and histological evaluation were detected in various tissues and organs, including the lung, heart, kidney, lymph nodes, spleen, liver, small intestine, and testis. The heart, lung, liver, kidney, lymph nodes, and spleen showed pathological changes. The pathological features include swelling, inflammation, cell degeneration, necrosis, and hemorrhage. The lesions are consistent with multisystemic inflammation. Tissue viral load results showed only heart, lung, liver, kidney, lymph nodes, and spleen was positive by qRT-PCR. Moreover, the pro-inflammation cytokines in serum increased a lot in the PCV3-inoculated group compared to the control group, demonstrating that the induced inflammation response may be the cause of tissue damage in PCV3-infection. This study demonstrated that PCV3 can produce mild pathological damage to multiple organs, especially multisystemic inflammatory cell infiltration and prolonged viremia, viral shedding in nasal secretions. This is the first in vivo characterization of PCV3 infection in the SPF piglets model using isolated PCV3 strain, and this is also the first time to show the gross and pathological lesion with all tissue and organs in the PCV3-inoculated group. Our findings might serve as a starting point for more investigation into PCV3’s pathogenic mechanism.

Obesity is a risk factor of many diseases, but could be beneficial to the individuals with bacterial infection. The present study was conducted to investigate the relationship between obesity and heart during nonfatal bacterial infection. Male normal (lean) and diet-induced obesity mice (DIO, fed with high-fat diet) were chosen to perform nasal instillation with E. coli to establish a nonfatal acute mouse model. The cardiac histopathology, inflammation and oxidative damage, as well as apoptosis were detected post-infection. The results revealed that the Escherichia coli (E.coli)-infected mice exhibited increased cardiac index, contents of IL-1β, IL-6, IL-8, TNF-α, leptin and resistin, levels of apoptotic proteins (caspase-3 and caspase-9, and bax/bcl-2 ratio), cardiac pathological changes and oxidative stress. Furthermore, these parameters were more serious in the lean mice than those in the DIO mice. In summary, our findings gave a new sight that E.coli infection impaired heart via histopathological lesions, inflammation and oxidative stress and excessive apoptosis of cardiomyocytes. Interestingly, obesity exerted attenuated effects on the heart of mice with non-fatal infection of E.coli through decreased inflammation, oxidative stress and apoptosis of cardiac tissue.

As an extensively environmental pollution, Nickel (Ni) represents a serious hazard to human health. The present study focused on exploring the mechanism of Ni-mediated nephrotoxicity, such as apoptosis, autophagy and oxidative stress. In the current work, NiCl2 treatment could induce kidney damage. Meanwhile, NiCl2 treatment elevated ROS production and MDA content and suppressed the antioxidant activity, which was characterized by reducing T-AOC, CAT, SOD activity and GSH content. For investigating the role of oxidative stress on NiCl2-mediated nephrotoxicity, N-acetyl cysteine (NAC, effective antioxidant and free radical scavenger) was co-treated with NiCl2. The results showed that NAC significantly suppressed the NiCl2-mediated oxidative stress and mitigated NiCl2-induced the kidney damage. Then, whether oxidative stress-induced autophagy and apoptosis were involved in NiCl2-induced nephrotoxicity was explored. The findings demonstrated that NAC relieved NiCl2-induced autophagy and reversed the activation of Akt/AMPK/mTOR pathway. Concurrently, the results indicated that NAC attenuated NiCl2-induced apoptosis, as evidenced by reduction of apoptotic cells and cleaved-caspase-3/− 8/− 9 together with cleaved-PARP protein levels. To sum up, our findings suggested that NiCl2-mediated renal injury was associated with oxidative stress-induced apoptosis and autophagy. This study provides new theoretical basis for excess Ni exposure nephrotoxic researches.

Copper (Cu), as a common chemical contaminant in environment, is known to be toxic at high concentrations. The current research demonstrates the effects of copper upon hepatocyte cell-cycle progression (CCP) in mice. Institute of cancer research (ICR) mice (n = 240) at an age of four weeks were divided randomly into groups treated with different doses of Cu (0, 4, 8, and 16 mg/kg) for 21 and 42 days. Results showed that high Cu exposure caused hepatocellular G0/G1 cell-cycle arrest (CCA) and reduced cell proportion in the G2/M phase. G0/G1 CCA occurred with down-regulation (p

Porcine reproductive and respiratory syndrome virus (PRRSV) is an important pathogen that poses a serious threat to the global pig industry. Sichuan Province is one of the largest pig breeding provinces in China. There is a lack of reports on the continuous surveillance and systematic analysis of prevalent strains of PRRSV in Sichuan Province in recent years. To fill this gap, a total of 539 samples were collected from 13 breeding regions in Sichuan during 2012–2020. The detection result showed that the positive rate of PRRSV was 52.32% (282/539). The ORF5s and Nsp2 were obtained and further analyzed, with Chinese reference strains downloaded from the GenBank. Phylogenetic analysis showed that the PRRSV strains sequenced in this study belonged to PRRSV-1 and PRRSV-2 (lineage 1, 3, 5 and 8). In total, 168 PRRSV-2 strains were selected for ORF5 analyses, and these strains were classified into sub-lineage 8.7 (HP-PRRSV), sub-lineage 5.1 (classical PRRSV), sub-lineage 1.8 (NADC30-like), sub-lineage 1.5 (NADC34-like) and sub-lineage 3.5 (QYYZ-like), accounting for 60.71% (102/168), 11.31% (19/168), 18.45% (31/168), 2.97% (5/168) and 6.55% (11/168) of the total analyzed strains, respectively. The Nsp2 of identified PRRSV strains exhibited a nucleotide identity of 44.5–100%, and an amino acid identity of 46.82–100%. The ORF5 of the identified PRRSV strains exhibited a nucleotide identity of 81.3–100%, and an amino acid identity of 78.5–100%. A sequence analysis of ORF5 revealed that the mutation sites of GP5 were mainly concentrated in HVR1 and HVR2 and the virulence sites. In summary, the HP-PRRSV, NADC30-like PRRSV, Classic-PRRSV, QYYZ-like PRRSV, NADC34-like PRRSV and PRRSV-1 strains exist simultaneously in pigs in Sichuan. NADC30-like PRRSV was gradually becoming the most prevalent genotype currently in Sichuan province. This study suggested that PRRSV strains in Sichuan were undergoing genomic divergence.

Interferons (IFNs) play a major role in the host’s antiviral innate immunity. In response to viral infection, IFNs bind their receptors and initiate a signaling cascade, leading to the accurate transcriptional regulation of hundreds of IFN-stimulated genes (ISGs). Porcine rotavirus (PoRV) belongs to genus Rotavirus of the Reoviridae family; the infection is a global epidemic disease and a major threat to the pig industry. In this study, we found that IFN-λ3 inhibited the replication of PoRV in both MA104 cells and IPEC-J2 cells, and this inhibition was dose-dependent. Furthermore, the antiviral activity of IFN-λ3 was more potent in IPEC-J2 cells than in MA104 cells. Further research showed that IFN-λ3 and IFN-α might inhibit PoRV infection by activating ISGs, i.e., MxA, OASL and ISG15, in IPEC-J2 cells. However, the co-treatment of IFN-λ3 and IFN-α did not enhance the antiviral activity. Our data demonstrated that IFN-λ3 had antiviral activity against PoRV and may serve as a useful antiviral candidate against PoRV, as well as other viruses in swine.

Although copper is among the indispensable trace elements in animal physiological processes, it exerts toxicity upon over-exposure. The present study aimed to investigate hepatocyte autophagy induced by CuSO4 and its potential mechanism. A total of 240 ICR mice (four-week-old, 120 males and 120 females) were randomly divided into four groups, in which mice separately received 0, 4, 8, and 16 mg/kg of Cu (Cu2+-CuSO4) for 42 d. The results of increased autophagosomes and autophagy marker LC3B brown cell staining showed that excessive intake of Cu enhanced hepatocyte autophagy. Simultaneously, Cu inhibited the activity of mTOR through suppressing mRNA and protein expressions in mTOR, which in turn up-regulated expression levels of ULK1 and initiated autophagy. Also, over-exposure to Cu increased mRNA and protein expressions of Beclin1, Atg12, Atg5, Atg16L1, Atg7, Atg3, and LC3 and decreased mRNA and protein expressions of p62. These results indicate that excess Cu can enhance hepatocyte autophagy via inhibiting the mTOR signaling pathway and regulating mRNA and protein expressions of factors implicated to autophagy in mice.

Background/Aims: Excessive fluoride intake can induce cytotoxicity, DNA damage and cell-cycle changes in many tissues and organs, including the kidney. However, the underlying molecular mechanisms of fluoride-induced renal cell-cycle changes are not well understood at present. In this study, we used a mouse model to investigate how sodium fluoride (NaF) induces cell-cycle changes in renal cells. Methods: Two hundred forty ICR mice were randomly assigned to four equal groups for intragastric administration of NaF (0, 12, 24 and 48 mg/kg body weight/day) for 42 days. Kidneys were taken to measure changes of the cell-cycle at 21 and 42 days of the experiment, using flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot methods. Results: NaF, at more than 12 mg/kg body weight, induced G2/M phase cell-cycle arrest in the renal cells, which was supported by the finding of significantly increased percentages of renal cells in the G2/M phase. We found also that G2/M phase cell-cycle arrest was accompanied by up-regulation of p-ATM, p-Chk2, p-p53, p-Cdc25C, p-CDK1, p21, and Gadd45a protein expression levels; up-regulation of ATM, Chk2, p53, p21, and Gadd45a mRNA expression levels; down-regulation of CyclinB1, mdm2, PCNA protein expression levels; and down-regulation of CyclinB1, CDK1, Cdc25C, mdm2, and PCNA mRNA expression levels. Conclusion: In this mouse model, NaF, at more than 12 mg/ kg, induced G2/M phase cell-cycle arrest by activating the ATM-Chk2-p53/Cdc25C signaling pathway, which inhibits the proliferation of renal cells and development of the kidney. Activation of the ATM-Chk2-p53/Cdc25C signaling pathway is the mechanism of NaF-induced renal G2/M phase cell-cycle arrest in this model.

Although many studies have confirmed that antimicrobial peptides (AMPs: PBD-mI and LUC-n) can be used as feed additives, there are few reports of their use in ruminants. The present study aimed to investigate the impact of AMPs on ameliorating rumen fermentation function and rumen microorganisms in goats. Eighteen 4-month-old Chuanzhong black goats were used in a 60-day experiment (6 goats per group). Group I was used as the control and was fed a basal diet, the group II were fed the basal diet supplemented with 2 g of AMPs [per goat/day] and group III were fed the basal diet supplemented 3 g of AMPs [per goat/day], respectively. Rumen fluid samples were collected at 0, 20 and 60 days. Bacterial 16S rRNA genes and ciliate protozoal 18S rRNA genes were amplified by PCR from DNA extracted from rumen samples. The amplicons were sequenced by Illumina MiSeq. Rumen fermentation parameters and digestive enzyme activities were also examined. Our results showed that dietary supplementation with AMPs increased the levels of the bacterial genera Fibrobacter, Anaerovibrio and Succiniclasticum and also increased the ciliates genus Ophryoscolex, but reduced the levels of the bacterial genera Selenomonas, Succinivibrio and Treponema, and the ciliate genera Polyplastron, Entodinium, Enoploplastron and Isotricha. Supplementation with AMPs increased the activities of xylanase, pectinase and lipase in the rumen, and also increased the concentrations of acetic acid, propionic acid and total volatile fatty acids. These changes were associated with improved growth performance in the goats. The results revealed that the goats fed AMPs showed improved rumen microbiota structures, altered ruminal fermentation, and improved efficiency regarding the utilization of feed; thereby indicating that AMPs can improve growth performance. AMPs are therefore suitable as feed additives in juvenile goats.

Fluoride overexposure is an environmental health hazard and can cause enamel and skeletal fluorosis. Previously we demonstrated that fluoride increased acetylated-p53 and its downstream target p21 in ameloblast-derived LS8 cells. However, p21 function in fluoride toxicity is not well characterized. This study seeks to gain a better understanding of how p53 down-stream mediators, p21 and MDM2, respond to fluoride toxicity. LS8 cells were treated with NaF with/without MG-132 (proteasome inhibitor) or Nutlin-3a (MDM2 antagonist). NaF treatment for 2−6 h increased phospho-p21, which can inhibit apoptosis. However, phospho-p21 and p21 were decreased by NaF at 24 h, even though p21 mRNA was significantly increased at this time point. MG-132 reversed the fluoride-mediated p21 decrease, indicating that fluoride facilitates p21 proteasomal degradation. MG-132 suppressed fluoride-induced caspase-3 cleavage, suggesting that the proteasome plays a pro-apoptotic role in fluoride toxicity. NaF increased phospho-MDM2 in vitro and in mouse ameloblasts in vivo. Nutlin-3a suppressed NaF-mediated MDM2-p21 binding to reverse p21 degradation which increased phospho-p21. This suppressed apoptosis after 24 h NaF treatment. These results suggest that MDM2-mediated p21 proteasomal degradation with subsequent phospho-p21 attenuation contributes to fluoride-induced apoptosis. Inhibition of MDM2-mediated p21 degradation may be a potential therapeutic target to mitigate fluoride toxicity.

Gut health is essential for animal growth because it can absorb nutrients more efficiently, promote growth, and protect the body from invasion by pathogenic microorganisms. Temperature, dissolved oxygen, water quality, nutrition level, pathogen, net fishing, and so on will affect the gut health of aquatic animals. Intestinal diseases in aquatic animals were often not easily detected, making them difficult to prevent and control. Therefore, establishing a stable and scientific evaluation standard of gut health was of great significance. This study evaluated the effects of gross pathological and histological parameters of largemouth bass and channel catfish infected by Aeromonas hydrophila. A total of 150 largemouth bass and 150 channel catfish were randomly divided into 5 groups: 1 control group (NC) and 4 challenge groups (CH, fish were infected with A. hydrophila by intraperitoneal injection with a concentration of 200 µL 1x108 CFU/mL, 1x107 CFU/mL, 1x106 CFU/mL, and 1x105 CFU/mL, respectively). After the challenge, largemouth bass' gross pathological and histological changes were observed on the 2nd, 6th, 9th, 12th, and 14th days. In contrast, channel catfish's gross pathological and histological changes were observed on the 3rd, 6th, 9th, 12th, and 15th day. In this study, regarding the "I See Inside" (ISI) methodology of poultry, a pathological evaluation method of fish intestinal health was established to comprehensively evaluate the intestinal health status of fish by gross pathological and histopathological score. In gross pathology, it was scored by the body surface and intestinal lesions. In histology, it was a metric evaluation of histological alterations in the intestine, converting macroscopic and microscopic alterations into numbers and then scoring. Each evaluation parameter sets up an "influence factor" (IF) according to the degree of influence of its pathological changes on intestinal function. The final score was the sum of the IF product and this parameter's score. The results of two kinds of fish showed that the gross pathological and histopathological scores correlated with the infection dose and time. And the significant difference in the score between the enteritis and control groups was observed. The results showed that the higher score, the more serious the pathological changes of fish infected by A. hydrophlia. From this, it can be concluded that the pathological evaluation method established can be used to evaluate the gut health of fish. [ABSTRACT FROM AUTHOR]