Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2006
Publication Date: 10/1/2006
Citation: Lo, M., Bulach, D.M., Powell, D.R., Haake, D.A., Matsunaga, J., Paustian, M., Zuerner, R.L., Adler, B. 2006. Effects of Temperature on Gene Expression Patterns in Leptospira interrogans Serovar Lai as Assessed by Whole-Genome Microarrays. Infection and Immunity. 74(10):5848-5859.
Interpretive Summary: Leptospirosis is a globally important zoonotic disease. Humans become infected via exposure to body fluids from infected animals, either directly or from contaminated water or soil. Invasion of the mammalian host involves an initial shift from ambient temperatures to 37°C and later to as high as 39°C during the febrile stage of infection. As in other pathogenic bacteria whose life cycle involves indirect modes of transmission, temperature is likely to be a key signal to leptospires of the transition from a free-living to an invasive stage. There is very little current information about how Leptospira responds at transcriptional or translational level to different temperatures. In this study, we used microarray technology to characterize global transcription profiles to identify factors, which could facilitate invasion and establishment of disease in the host.
Technical Abstract: The availability of genome sequences for two serovars of Leptospira interrogans, Lai and Copenhageni, has opened up opportunities to examine global transcription profiles using microarray technology. Temperature is a key environmental factor, which is known to affect leptospiral protein expression. Since Leptospira spp. are able to grown at a range of temperatures, transcriptional changes were compared between cultures grown at 20°C, 30°C, 37°C and 39°C to represent ambient temperatures in the environment, growth under laboratory conditions, and temperature in the healthy and febrile host respectively. Furthermore, cultures that had been shifted overnight to 37°C were compared with those grown long-term at 30°C and 37°C in order to identify genes that are differentially expressed in the early stages of infection. Comparison of data sets from the physiological vs environmental experiments with the upshift experiments provided a novel insight into possible transcriptional changes at different stages of infection. Changes include differential expression of chemotaxis and motility genes, signal transduction systems and genes encoding proteins involved in alteration of the leptospiral outer membrane.