Study Of Goat Pasteurella Multocida Infection Effect Mice Lung Transcriptome

Pasteurellosis is a bacterial disease that often appears in the breeding industry.Under normal circumstances,Pasteurellosis is widely present in animals without causing disease.When the immunity of animals is reduced or the feeding environment is deteriorated,it can multiply and damage animal health and bring great economic damage to animal husbandry.In this study,Pasteurella multocida strain HN01 from goat preserved in the laboratory was selected as the research object.The related characteristics and pathogenesis were preliminarily explored and the following experimental results were obtained:In experiment 1,gram staining was performed on Pm strains of HN01.The growth curve of Pm strains of HN01 was plotted within 30 h,and the equation of linear regression was obtained.The LD₅₀test of SPF KM mice was conducted by using the bacterium.Finally,testing the LD₅₀of SPF KM mice was 3.16×10⁴CFU.Pathological section showed that a large number of inflammatory cells and red blood cell were observed in the lung and spleen tissues,and alveolar epithelial cells were shed.In experiment 2,SPF KM mice were intraperitoneally injected with HN01 strain Pm liquid of 50LD₅₀,and freshly dead lung tissues of mice were collected and sent to the company for RNA extraction and transcriptome sequencing.The sequencing results showed that:（1）The sample quality of each group was qualified,the proportion of Reads with base quality≥Q30 was higher than 94%,and the matching rate with the reference genome was about 95%.（2）Compared with the control group,there were 2976 differentially expressed genes with a significant value of P<0.05 and|log2（fold change）|≥1,among which the number of genes with increased and decreased expression was 1605 and 1371,respectively（3）After GO enrichment analysis of differentially expressed genes,it was found that the number of GO terms enriched in the three GO classifications was similar,in which GO terms such as virus assembly（GO:0019068）,immune reaction（GO:0006955）and cytoplasm（GO:0005829）were significantly enriched.（4）After KEGG enrichment analysis of differentially expressed genes,it was found that differentially expressed genes were significantly enriched in the pathway related to the interaction between viral proteins and cytokines and receptors（ko04061）,the MAPK transduction pathway related to cell proliferation and apoptosis（ko04010）,and the cytokine receptor-related pathway（ko04060）,etc.（5）The enrichment factor of ferroptosis pathway（ko04216）was up to 1.4,and the significantly differentially expressed genes in the pathway were basically up-regulated.（6）The expression levels of Il1r2,Cd14,Cd33,Mt1,Nfkbia,Saa3,S100a9,Ccl9 and STAT3 were significantly up-regulated and the expression level of Il4ra was significantly down-regulated by q RT-PCR.In experiment 3,the iron-regulated gene Ex BD was amplified with the genome of Pm HN01 as the template,induced the expression of target protein,and carried out the corresponding bioinformatics analysis.The results showed that the amplified gene band was at 390 bp,and the protein band was at 19 k D by SDS-PAGE and Western blot,both of which met the expectation.The gene in HN01 strain was the most closely related to Pm HN02 strain,and the Exb D protein was predicted to be an acid stable protein withα-helix and random coil as the main secondary structure.In conclusion,the LD₅₀of Pm HN01 strain is 3.16×10⁴CFU,and the Pm mainly causes lung and spleen injury in mice.After Pm infects mice,it causes significant differences in immune and transduction pathways or related genes in mice.