| In this experiment,the rumen fluid of Holstein cows with permanent rumen fistula was collected,and the culture medium with sodium carboxymethyl cellulose as the sole carbon source was selected.A strain with fiber degradation ability was isolated and identified as Bacillus licheniformis by combining traditional culture identification methods and molecular biology methods.The screened Bacillus licheniformis were separated into two groups β-1,4-glucoside bond microcrystalline cellulose and cellobiose were used as the sole carbon source for culture.The culture broth was sequenced by prokaryotic transcriptome and proteome,and the sequencing data were analyzed.The results show that:(1)The results showed that the strains were white colonies with rough surface and irregular edge.After long-term culture,the colony edge was hairy,the color was deepened,and the surface had viscous liquid.Gram positive bacilli with long rod shape,single,paired or chain arrangement.The strain has high temperature tolerance and can grow on various components.16S rDNA high-throughput sequencing showed that the selected strain was Bacillus licheniformis.The Bacillus licheniformis contains a variety of carbohydrate enzyme genes,participates in the synthesis of a variety of enzymes,and has the ability to decompose and utilize a variety of sugars.(2)Under two different carbon sources,the chemotaxis,flagella assembly and the synthesis of antibacterial substances were different.The chemotaxis and flagella assembly growth genes of Bacillus licheniformis were significantly up regulated in the condition of microcrystalline cellulose culture;The expression of the genes of synthetic vancomycin antibiotics and Bacillin was higher,but the expression of the transporter gene of Bacillin was down regulated.(3)The glycolysis,inositol metabolism and glucose metabolism of Bacillus licheniformis were different because of carbon sources.The fermentation process of glycolysis was inhibited,the amount of lactate was reduced and the amount of cellulase was more in the sugar heterogenetic pathway;Under the condition of microcrystalline cellulose,it had denitrification effect on nitrogen compounds.(4)In the process of gene expression,the Bacillus licheniformis is relatively low in mRNA and protein,and has post transcriptional regulation.Both mRNA and protein indicated that it regulated ABC transporters and membrane surface receptors,and the chemotaxis,flagella assembly and movement changed with different carbon sources.In conclusion,the isolated strain is a subspecies of Bacillus licheniformis,which can participate in the synthesis of a variety of carbohydrate enzymes.Different carbon sources will lead to different gene and protein expression levels of Bacillus licheniformis,and change carbohydrate metabolism,bacterial chemotaxis,flagellum assembly,ABC transporter system,lactic acid synthesis and denitrification. |
