Effect Of Changes In Basigin During Post-slaughter Maturation On Beef Quality

In this paper,the longissimus dorsi muscle of Qinchuan cattle was used as the research object to study the effects of basic immunoglobulin changes on beef quality and energy metabolism during storage at 4℃ after slaughter.The quality characteristics and energy substance changes of Qinchuan beef during different post-slaughter storage time(0,2,4,6 and 8 days)were determined.4D-LFQ protein omics method was used to identify the change of BSG expression and the differential proteins related to basic immunoglobulin.KEGG pathway analysis,GO analysis and other bioinformatics methods were used to analyze the effect of basic immunoglobulin on the quality change of Qinchuan beef.The BSG inhibitor tunicamycin was injected into the longissimus dorsi muscle of Qinchuan beef after slaughter to analyze the effects of BSG inhibitor on MAPK signaling pathway and apoptosis.The main results are as follows:Taking the longissimus dorsi muscle of Qinchuan cattle stored at 4℃ as the object,the relationship between the change of BSG expression and the change of energy substance level and meat quality in Qinchuan beef during different storage periods at 4℃ was studied.During the storage period of 0-8 d,the expression of BSG increased first and then decreased.The contents of ATP,ADP,AMP and NADH,the basic substances of energy,all showed a downward trend.The quality index pH first decreased and then increased.The shear force first increased and then decreased(P<0.01),and the increase was smaller than the decrease.The MFI and b*values showed an extremely significant upward trend(P<0.01),while the L*value,a*value,shearing force and cooking loss all showed a trend of increasing first and then decreasing.The results of correlation analysis showed that the expression of BSG in Qinchuan cattle during postmortem maturity was positively correlated with a*value(P<0.05),and the correlation coefficient r was 0.961.It was negatively correlated with ADP content and NADH content(P<0.05),and the correlation coefficients were-0.618 and-0.791,respectively.It was positively correlated with L*value and cooking loss(P<0.01),and the correlation coefficients were 0.813 and 0.761 respectively.There was no significant correlation with ATP content,AMP content,b*value and shear force.The results showed that the change of BSG expression in longissimus dorsi muscle of Qinchuan cattle during maturity was closely related to water retention,color and energy metabolism of beef.Using 4D-nonstandard quantitative protein omics technology to explore the change mechanism of BSG in Qinchuan beef during storage,setting the difference multiple as 1.2,identifying the related differential expression protein,and screening out 28 differential protein related to BSG change through enrichment of functional characteristics,and making correlation analysis and bioinformatics analysis with BSG expression.Through GO enrichment analysis,it was found that 5 BP,3 CC and 2 MF were significantly enriched in 4 d compared with 0 d group.8 d compared with 4 d group significantly enriched to 2 BP,14 MF,8 d compared with 0 d group significantly enriched to 5 BP,4 CC,4 MF.Through the analysis of KEGG pathway enrichment,it was found that 4 d compared with 0 d group,there was a significant annotation on one KEGG pathway,which was oxidative phosphorylation(bta00190).8 d compared with 4 d group,3 KEGG pathways were noted,namely cGMP-PKG signal pathway(bta004022),calcium signal pathway(bta04020)and MAPK signal pathway(bta04010).The results showed that BSG-related protein had catalytic activity,hydrolase activity,ion binding,proton transport ATP synthase activity in cells,combined with ATP,adenosine ribonucleotide,purine ribonucleoside triphosphate,ribonucleotide,carbohydrate derivatives,and participated in the regulation of molecular functions,hydrogen ion transmembrane transport,etc.The above biological functions led to changes in Qinchuan’s muscle structure,promoted the degradation of cell structural proteins,and caused changes in the level of energy substances in meat,thus further affecting meat quality.3.Inject BSG inhibitor itamycin into the longissimus dorsi muscle of slaughtered Qinchuan beef,and determine the expression levels of MAPK pathway related protein ARAF,ERK1,KRAS+HRAS+NRAS and MEK1/2 during storage at 4℃ by protein western blot.The relative expression of caspase-3 was determined by apoptosis detection kit.The effects of BSG on MAPK signaling pathway and apoptosis were analyzed.The main results are as follows:Compared with the blank group,the relative expression levels of protein ARAF,ERK1,KRAS+HRAS+NRAS,and MEK1/2,which are key proteins of MAPK pathway in the itamycin group,were significantly decreased,indicating that BSG inhibitors inactivate MAPK signaling pathway.This laid a good foundation for studying the influence of BSG on MAPK signaling pathway.fter inhibiting the expression of BSG,compared with the blank group,the relative expression of caspase-3 in the tunicamycin group increased significantly,which indicated that apoptosis was an important link of cell injury,and the N-terminal structure of BSG was acted by tunicamycin to deglycosylate protein.By inhibiting the folding of intracellular protein,its biological activity is inhibited,thus inducing cell apoptosis.