Brucella melitensis global gene expression study provides novel information on growth phase-specific gene regulation with potential insights for understanding Brucella:host initial interactions.
BACKGROUND
Brucella spp. are the etiological agents of brucellosis, a zoonotic infectious disease that causes abortion in animals and chronic debilitating illness in humans. Natural Brucella infections occur primarily through an incompletely defined mechanism of adhesion to and penetration of mucosal epithelium. In this study, we characterized changes in genome-wide transcript abundance of the most and the least invasive growth phases of B. melitensis cultures to HeLa cells, as a preliminary approach for identifying candidate pathogen genes involved in invasion of epithelial cells.


RESULTS
B. melitensis at the late logarithmic phase of growth are more invasive to HeLa cells than mid-logarithmic or stationary growth phases. Microarray analysis of B. melitensis gene expression identified 414 up- and 40 down-regulated genes in late-log growth phase (the most invasive culture) compared to the stationary growth phase (the least invasive culture). As expected, the majority of up-regulated genes in late-log phase cultures were those associated with growth, including DNA replication, transcription, translation, intermediate metabolism, energy production and conversion, membrane transport, and biogenesis of the cell envelope and outer membrane; while the down-regulated genes were distributed among several functional categories.


CONCLUSIONS
This Brucella global expression profile study provides novel information on growth phase-specific gene expression. Further characterization of some genes found differentially expressed in the most invasive culture will likely bring new insights into the initial molecular interactions between Brucella and its host.
Rossetti
Carlos A
CA
Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77483-4467, USA. crossetti@cvm.tamu.edu
Galindo
Cristi L
CL
Lawhon
Sara D
SD
Garner
Harold R
HR
Adams
L Garry
LG
D017347:Brucella melitensis / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D002006:Brucellosis / Q000382:microbiology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D012329:RNA, Bacterial / Q000378:metabolism
D012329:RNA, Bacterial