Purpose: This study aimed to analyze the amount of expression of various genes of Lactobacillus animalis NP51 at different temperatures 25°C (environment temperature), 39°C (host temperature-bovine), and 45°C (animal feed temperature).
Methods: RNA-Seq was performed to characterize differences in the transcriptome of Lactobacillus animalis NP51. The bacterial strain was grown overnight at 37°C for 18 h; overnight cultures were diluted into fresh medium and incubated at 25, 39, and 45°C until mid-logarithmic phase was reached. Total RNA extracted from two biological replicates of each temperature was rRNA depleted; individually bar-coded RNA-Seq libraries were prepared and sequenced on a MiSeq instrument. Raw data sets were assembled using de novo assembly. Gene expression was analyzed using DNAStar Array Star.
Results: To obtain the level of expression, host temperature was set up as control. By comparing 25°C to the control, 572 genes were identified as differentially expressed, 488 genes showed reduced expression while 84 increased expression. At 45°C, 54 genes were differentially expressed, 23 showed reduced expression and 31 showed increased expression. These include the downregulation of PTS gene expression, used for the uptake of carbohydrates; the late competence protein ComGA required for the competence-related block in chromosome replication, and the upregulation of the EmrE multidrug resistance protein.
Significance: This study provides important information about the transcriptional differences of Lactobacillus animalis NP51 at low and high temperatures providing the basis for the characterization of genes with a potential role in the inhibition of foodborne pathogens.