Porcine hemagglutinating encephalomyelitis virus(PHEV)is highly prevalent and wide-ly distributed,and its harm on pig farming is of great concern,therefore,effective strategies for prevention and control are necessary.In this study,chloroquine(CQ)was selected and its effect and mechanism on replication and proliferation of PHEV were investigated.The results showed that CQ(1-100 mmol/L)inhibits the replication and proliferation of PHEV in a dose-dependent manner and has no cytotoxicity on N2a cells.The production of inflammatory cytokines and activa-tion of NF-κB signaling pathway were both inhibited by CQ concentration at 50 mmol/L in PHEV-infected N2a cells.In conclusion,we confirmed the inhibition of CQ in replication and proliferation of PHEV.It is expected to be applied to the prevention and treatment of PHEV in clinical.

To investigate the expression and distribution of follicular dendritic cell(FDC)and follic-ular helper T cells(Tfh)in mouse spleen and lymph nodes induced by foot-and-mouth virus-like particles(FMDV-VLPs),the recombinant pCMV-HA-HBcAg-VP1-VP4 plasmid was transfected into CHO-K1 cells to prepare FMDV-VLPs,and the recombinant FMDV VP1-VP4 protein was expressed and purified through a prokaryotic expression system.BALB/c mice were subcutaneous-ly immunized with FMDV-VLPs(VLP group)and recombinant FMDV VP1-VP4 protein(VP1-VP4 group),and PBS control group(PBS group)was set up.At 21 d post primary immunization(dpi),booster immunization was carried out.Spleen,shoulder lymph nodes,and submandibular lymph nodes were collected at 7,28,42,72 and 102 dpi,and frozen sections were prepared.Immu-nohistochemical staining was used to observe the expression and distribution of FDC and Tfh.The results showed that the number of FDC and Tfh cells in the VLP group in the spleen and lymph nodes showed a gradual increase from 7 to 42 dpi,and gradually decreased to non-immune levels starting from 72 dpi.The results indicate that FMDV-VLPs can induce the formation of GC in the spleen and lymph nodes,and the number of FDC and Tfh cells in GC can last for at least 42 d.This study provides a theoretical basis for the study of the immune memory response mechanism of B cells induced by FMDV virus-like particles.

The receptors of Newcastle disease virus(NDV)are sialic acid receptors that mainly in-clude neu5ac-α-2,3gal-β-1,4Glc(SAα2,3Gal)and neu5ac-2-s-α-2,6Gal10Me(SAα2,6Gal).The distribution and abundance of the two receptors in host cells have important effects on virus sus-ceptibility and intracellular proliferation.In order to further explore the effects of sialic acid recep-tors on susceptibility and proliferation characteristics of NDV different strains,the expression lev-els of SAα2,3Gal and SAα2,6Gal receptors on BHK-21 cell membrane were adjusted by overex-pression and RNAi assays,and the TCID50 values were determined after different BHK-21 cells were inoculated with NDV strains Ⅰ and LaSota.The results suggested that NDV strain LaSota preferentially binds to SAα2,6Gal and strain Ⅰ selectively binds to SAα2,3Gal receptor.Further-more,the viral titers of NDV strains LaSota and Ⅰ in cell culture were positively correlated with the expression levels of SAα2,6Gal and SAα2,3Gal receptors on host cell membrane respectively.In conclusion,our studies provide an understanding of the relationship between infectivity of NDV different strains and receptor types of host cell,and provide a method to increase viral titer of NDV for cell-based vaccine production.

To establish an immunochromatographic method for rapid detection of caprine enterovir-us(CEV),the monoclonal antibody against CEV VP1 protein was used as gold-labeled monoclonal antibodies,and the purified rabbit-derived polyclonal antibody of CEV-VP1 and sheep anti-mouse IgG were used as the detection line and quality control line,respectively.The colloidal gold immu-nochromatographic test strips for CEV were prepared according to the principle of double antibody sandwich,evaluated,and applied for clinical specimen detection.The results showed that the meth-od specifically recognized CEV without cross-reaction with bovine enterovirus and bovine viral di-arrhea virus.The minimum detection limit of the method was 102.49 TCID50/mL and had good re-producibility.The prepared test strips had a shelf life of three months kept at 4 ℃.Detection of clin-ical samples using the immunochromatographic test strips showed 100％coincidence rate with RT-PCR method.In conclusion,the colloidal gold immunochromatographic test strips for detection of the emerging CEV with good specificity,sensitivity and repeatability,which provides a new techni-cal means easily used for the rapid detection/diagnosis and epidemiological investigation on CEV infection.

Different animals in Xinjiang carry Escherichia coli O157:H7(E.coli O157:H7),but the connection between these strains is not clear.This study aims to understand the evolutionary sub-group of E.coli O157:H7,the distribution of the dominant genetic lineage,the biofilm formation ability,the carriage of mobile genetic elements and their drug resistance profile.E.coli O157:H7 was identified by PCR.Multilocus sequence typing(MLST)protocol was used for E.coli O157 to detect ST type,plasmid replicon and integron genes.Biofilm formation ability was determined by crystal violet microplate,and Kirby-Bauer was used to detect drug resistance.The results showed that 46.7％(7/15)of E.coli O157:H7 belongs to Group A,53.3％(8/15)of E.coli O157:H7 be-longs to Group E.Sheep source were mainly prevalent in Group A(4/6).Cattle sources are mainly Group E(6/7).A total of six ST types were detected:ST11(8/15),ST-206(1/15),ST-6126(3/15),ST-1640(1/15),ST-178(1/15),ST-4550(1/15).Two strains had a moderate biofilm-form-ing capacity,two strains had a weak biofilm-forming capacity,10 strains have no biofilm-forming capacity.All were multidrug-resistant strains,with complete resistance to lincomycin,oxacillin,clindamycin,vancomycin,midemycin and cefthiophene,and 88％-94％resistance to poly-myxin B,ampicillin,penicillin G and erythromycin,they are highly drug resistant.The five resist-ance genes detected were acrA(66.66％,10/15),tolC(73.33％,11/15),qurS(13.33％,2/15),floR and qurA(6.67％,1/15).Four plasm id replicons were detected,they were IncP(66.66％,10/15),IncFrepB(86.67％,13/15),IncFIA(6.67％,1/15),IncFIB(66.66％,10/15).Two class Ⅰ integrons were detected and they were ISCR1(33.33％,5/15),ISECP1(20％,3/15).The re-sults showed that E.coli O157:H7 in Xinjiang was predominantly prevalent in Group A and Group E.Sheep sources were predominantly prevalent in Group A,and cattle sources were predominantly prevalent in Group E.The ST types were widely distributed,with ST11 types being the predomi-nant type,the biofilm-forming ability was weak,and the resistance was strong,all of them were multi-drug-resistant strains,and the resistance genes were mainly externally excreted from the pumps,and the resistance genes had more spreading elements.

This study aims to analyze the biological characteristics such as pathogenicity,serotype,virulence genes,and drug resistance of Escherichia coli(E.coli)causing diarrhea in dairy and meat calves in different farms in the Northern Hebei.From 2022 to 2023,120 diseased tissue sam-ples(feces,anal swabs,and livers)of calves(0-2 months old)suffering from diarrhea in the north-ern Hebei region were collected.The detection of viral and parasitic pathogens was negative.Bacte-rial isolation and cultivation,morphological observation,biochemical identification,and PCR meth-ods were used to identify E.coli.Biological characteristics such as pathogenicity,serum typing,vir-ulence genes,and drug resistance were detected using mouse virulence test,glass plate agglutina-tion test,PCR method,and K-B drug sensitivity paper method,and determine the median lethal dose(LD50)of representative strains of dominant serotypes in mice respectively.The results showed that 76 strains of E.coli were isolated,and 56 strains were pathogenic E.coli that could cause varying degrees of death in mice,with mortality rates all above 40％.Among 56 pathogenic E.coli strains,O6 and O152 were the dominant pathogenic serotypes,among which 48 strains(85.7％)were enterotoxic E.coli(ETEC),6 strains(10.7％)were enteropathogenic E.coli(EPEC),and 2 strains(3.6％)were enterohemorrhagic E.coli(EHEC).The detection rates of vir-ulence genes fyuA,irp2,fliC,stx1,stx2,K88,K99,eaeA and ler were over 50％,while the de-tection rates of other types of virulence genes were 3.6％to 37.0％.The resistance rates to nine drugs such as ampicillin,neomycin,and amoxicillin were over 42.9％,and the resistance rates to other drugs were 12.5％to 32.1％,showing multiple drug resistance and at least resistance to three types of antibiotics.The LD50 values of the dominant serotype of representative strains ETO 152 strain and EPO6 were 3.16×104 and 3.22×106 CFU/mL,respectively.This study can provide ref-erence for the prevention and control of E.coli disease in dairy and meat calves in the Northern Hebei region.

The decrease in blood glucose in perinatal dairy cows affects the energy supply and im-mune function of peripheral blood neutrophils(PMN).Fibroblast growth factor 21(FGF21)is an important regulator of glucose metabolism,and serum FGF21 levels in some perinatal cows are significantly elevated after farrowing.In order to explore the effect of FGF21 on PMN glucose ho-meostasis in perinatal dairy cows,the cows were divided into high FGF21 group(high FGF21,n=8,FGF21＞800 ng/L)and low FGF21 group(low FGF21,n=8,FGF21＜200 ng/L)within 3 weeks postpartum.The results showed that compared with the low FGF21 group,the glucose up-take of PMN and the mRNA expression of glucose transporters SLC2A1 and SLC2A3 were signifi-cantly increased in the high FGF21 group.The activities of phosphofructokinase 1(PFK1)and glu-cose-6-phosphate dehydrogenase(G6PDH)were significantly increased,and the activity of glyco-gen synthase(GCS)was significantly decreased in PMN in the high FGF21 group.The lactate con-tent and ATP content of PMN were significantly increased,and the mRNA and protein expressions of hexokinase(HK2)and PFK1 were significantly increased in the high FGF21 group.These re-sults indicated that the uptake and utilization of glucose by PMN in perinatal peripheral blood FGF21 increased to ensure the ATP supply of PMN,which provided a theoretical basis for the pro-posal of a new strategy to alleviate immunosuppression in perinatal dairy cows.

Ketosis is an energy metabolism disorder occurring frequently in periparturient dairy cows,primarily attributed to elevated non-esterified fatty acid(NEFA)levels resulting from nega-tive energy balance(NEB).Excessive NEFA will be incompletely oxidated into large amounts of ketone bodies or be re-esterified and deposit in the liver as a consequence of hepatic limited oxida-tive capacity,ultimately leading to ketosis and fatty liver.Hypoxic microenvironments are com-monly found during the progression of various liver diseases.Hypoxia inducible factor-2 alpha(HIF-2 alpha)has been identified as a crucial regulator of lipid metabolism.However,it is still un-clear the association between HIF-2α and disrupted lipid metabolism in the livers of in ketotic cows.This study aims to investigate the effect of high concentrations of NEFA on HIF-2α expres-sion and cellular oxygen homeostasis through bovine liver tissue and primary hepatocytes.In vivo,hepatic triglyceride(TAG)content was assessed to determine the extent of hepatic lipid accumula-tion,and HIF-2α protein and mRNA levels were analyzed by immunohistochemistry staining,Western blot and qRT-PCR assay in liver tissue samples from dairy cows;in vitro,bovine primary hepatocytes were treated with different concentrations of NEFA.Oil Red O staining and TAG con-tent assay were performed to determine hepatocellular steatosis extent,and immunofluorescence staining.Western blot,and qRT-PCR were performed to analyze HIF-2α expression,in addition,lu-minescent oxygen sensor[Ru(dpp)3]Cl2 was added to indicate intracellular oxygen levels.These results showed a significant increase in TAG content and elevated HIF-2α expression in the liver tissue of ketotic cows,and high concentrations of NEFA induced lipid accumulation,upregulation of HIF-2α expression,and intracellular hypoxia in bovine primary hepatocytes.These findings sug-gested that HIF-2α was significantly"activated"in the liver of ketotic cows and high concentration of NEFA-induced bovine primary hepatocytes,and that high concentrations of NEFA induced in-tracellular hypoxia in vitro.This study provides a potential molecular target for further investiga-tion of the mechanism underlying hepatic lipid metabolism disorders in ketotic cows.

This study aims to clarify the incidence and prevention status of dairy cow mastitis in 79 large-scale pastures in China in 2022,reduce the incidence of dairy cow mastitis,and provide scien-tific basis for formulating prevention and control strategies for dairy cow mastitis in large-scale pastures suitable for China's national conditions.The research team relied on the large-scale ranch of the Comprehensive Experimental Station of National Dairy Industry Technology System to car-ry out research.A total of 79 questionnaires were received.The information on the stock of large-scale farms,the proportion of cows in the herd,the level of cow yields,the incidence and cure rate of cow mastitis,the prevention and control of cow mastitis,diagnosis and treatment programs of cow mastitis,the cost of treating cow mastitis,and the culling rate of farms was collected.Chi-square test and correlation analysis were carried out on the incidence of mastitis in dairy cows and the prevention and control plan,treatment plan,yield level and elimination rate of mastitis in dairy cows by descriptive statistical cross table.The incidence of cow mastitis in some pastures was con-trolled between 5％and 10％,and the cure rate was mostly as high as 98％.According to the co-hort analysis,the importance of prevention and control measures for dairy cow mastitis was as fol-lows:DMT＞DHI＞milk yield＞milk traits＞breast apparent change＞electrical conductivity＞CMT.The importance of treatment measures for dairy cow mastitis is as follows:DMT＞DHI＞milk yield＞milk traits＞breast apparent changes＞electrical conductivity＞CMT.The importance of treatment measures for mastitis is as follows:traditional Chinese medicine＞pathogen detection and drug sensitivity test＞non-steroidal anti-inflammatory drugs＞regular maintenance of milking equipment＞normal milking without treatment＞broad-spectrum antibiotics.The incidence of mas-titis in dairy cows is moderately positively correlated with the yield per unit area,that is,the in-crease in the incidence of mastitis in dairy cows has a certain impact on the yield per unit area of dairy cows.Economic analysis shows that the treatment cost of mastitis is closely related to the in-cidence rate,and the treatment cost of pasture with higher incidence rate is higher.Pastures with higher yields usually have more efficient means of disease prevention and control,and the corre-sponding treatment costs are lower.In conclusion,China's large-scale pastures should strengthen the scientific feeding management level,improve the prevention and control methods to reduce the incidence of cow mastitis,improve the cure rate,and reduce the cost of pasture treatment.

This study aims to explore the mechanism of Shenling Baizhu San(SLBZS)in the treat-ment of ulcerative colitis(UC)based on systematic network pharmacology and in vivo experimen-tal verification.Systematic network pharmacology was used to predict the core targets and key pathways of the SLBZS in the treatment of UC,it was further validated in UC model of BALB/c mice which were established with DSS[3.5％(w/v)],and SLBZS was given orally for treatment at the same time.Network analysis of SLBZS identified 153 active compounds and 68 compound-re-lated targets correlated with UC.Additionally,5 core active compounds were obtained,such as rob-inin,luteolin,kaempferol,quercetin,denudatin B.Most of the compounds have proven to have phar-macological activities.Based on PPI network and pathway enrichment studies,SLBZS may exert anti-inflammatory,immunological regulation,and participate in the process of apoptosis through regulating IL6,TNF,IL1B,PTGS2,TP53,STAT3,CASP3,IL10,CXCL8,IL2,PPARG,PTPRC,IFNG,MTOR,MMP9,so as to affect cell differentiation,TNF signaling,cancer signaling,IL-17 signaling,NF-Kappa B signaling of Th17 cell.The results of in vivo animal experiments showed that SBP could significantly improve the clinical symptoms and colonic pathological changes of UC mice,regulate the abnormal changes of blood routine indexes,increase the serum inflammatory factors IL-4 and IL-10,and reduce the contents of IL-6,IL-2,IL-1β and TNF-α.These results indi-cates that SBP can treat ulcerative colitis through TNF signaling pathway and NF-Kappa B signa-ling pathway.