Global transcriptional analysis of Mycoplasma hyopneumoniae following exposure to norepinephrine

• Published in: Microbiology (Society for General Microbiology) Vol. 154; no. 9; pp. 2581 - 2588
• Main Authors: Oneal, Michael J, Schafer, Erin R, Madsen, Melissa L, Minion, F. Chris
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-09-2008; Society for General Microbiology
• Subjects: Animals; Bacteriology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Genes, Bacterial; Genetics; Metabolism. Enzymes; Microbiology; Mycoplasma; Mycoplasma hyopneumoniae; Mycoplasma hyopneumoniae - drug effects; Mycoplasma hyopneumoniae - genetics; Mycoplasma hyopneumoniae - growth & development; Norepinephrine - pharmacology; Oligonucleotide Array Sequence Analysis; Pneumonia of Swine, Mycoplasmal - microbiology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Bacterial - genetics; RNA, Messenger - genetics; Swine; Transcription, Genetic; Mollicutes; Mycoplasmatales; Mycoplasma hyopneumoniae; RNA; Transcription; DNA chip; Bacteria; Norepinephrine; Catecholamine; Veterinary; Reverse transcription polymerase chain reaction; Mycoplasmataceae
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2008/020230-0

Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA 50011, USA
Correspondence F. Chris Minion fcminion{at}iastate.edu
Mycoplasma hyopneumoniae , a component of the porcine respiratory disease complex, colonizes the respiratory tract of swine by binding to the cilia of the bronchial epithelial cells. Mechanisms of pathogenesis are poorly understood for M. hyopneumoniae , but previous work has indicated that it responds to the environmental stressors heat shock, iron deprivation and oxidative compounds. For successful infection, M. hyopneumoniae must effectively resist host responses to the colonization of the respiratory tract. Among these are changes in hormonal levels in the mucosal secretions. Recent work in the stress responses of other bacteria has included the response to the catecholamine norepinephrine. The idea that M. hyopneumoniae can respond to a host hormone, however, is novel and has not previously been demonstrated. To test this, organisms in the early exponential phase of growth were exposed to 100 µM norepinephrine for 4 h, and RNA samples from these cultures were collected and compared to RNA samples from control cultures using two-colour PCR-based M. hyopneumoniae microarrays. The M. hyopneumoniae response included slowed growth and changes in mRNA transcript levels of 84 genes, 53 of which were upregulated in response to norepinephrine. A larger proportion of the genes upregulated than those downregulated were involved with transcription and translation. The downregulated genes were mostly involved with metabolism, which correlated with the reduction in growth of the mycoplasma. Approximately 51 % of the genes were hypothetical with no known function. Thus, in response to norepinephrine, M. hyopneumoniae appears to upregulate protein expression while downregulating general metabolism.
Abbreviations: qRT-PCR, quantitative real-time reverse transcriptase polymerase chain reaction
The Gene Expression Omnibus ( http://www.ncbi.nlm.nih.gov/geo ) accession number for microarray data for this paper is GSE8494.
A supplementary table with details of genes differentially expressed during exposure to 100 µM norepinephrine and a supplementary figure showing the locations of significantly regulated genes on the M. hyopneumoniae chromosome are available with the online version of this paper.