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Updated: May 24, 2026
Microscopy-based Assays for High-throughput Screening of Host Factors Involved in Brucella Infection of Hela Cells
Published on: August 5, 2016
Differential expression of iron acquisition genes by Brucella melitensis and Brucella canis during macrophage
Linda Eskra1, Jill Covert, Jeremy Glasner
1Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
Abstract:
Brucella spp. cause chronic zoonotic disease often affecting individuals and animals in impoverished economic or public health conditions; however, these bacteria do not have obvious virulence factors. Restriction of iron availability to pathogens is an effective strategy of host defense. For brucellae, virulence depends on the ability to survive and replicate within the host cell where iron is an essential nutrient for the growth and survival of both mammalian and bacterial cells. Iron is a particularly scarce nutrient for bacteria with an intracellular lifestyle. Brucella melitensis and Brucella canis share ~99% of their genomes but differ in intracellular lifestyles. To identify differences, gene transcription of these two pathogens was examined during infection of murine macrophages and compared to broth grown bacteria. Transcriptome analysis of B. melitensis and B. canis revealed differences of genes involved in iron transport. Gene transcription of the TonB, enterobactin, and ferric anguibactin transport systems was increased in B. canis but not B. melitensis during infection of macrophages. The data suggest differences in iron requirements that may contribute to differences observed in the lifestyles of these closely related pathogens. The initial importance of iron for B. canis but not for B. melitensis helps elucidate differing intracellular survival strategies for two closely related bacteria and provides insight for controlling these pathogens.
Insights
Brucella canis and Brucella melitensis differ in iron transport strategies, impacting their intracellular survival. Understanding these iron requirements offers insights into controlling these zoonotic pathogens.
Area of Science:
- Microbiology
- Pathogen-host interactions
- Zoonotic diseases
Background:
- Brucella spp. are chronic zoonotic pathogens lacking obvious virulence factors.
- Iron availability is crucial for pathogen survival, especially for intracellular bacteria.
- Brucella melitensis and Brucella canis exhibit distinct intracellular lifestyles despite genomic similarity.
Purpose of the Study:
- To investigate the differences in gene transcription related to iron transport between Brucella melitensis and Brucella canis.
- To understand how iron acquisition contributes to the differing intracellular lifestyles of these closely related Brucella species.
Main Methods:
- Comparative transcriptome analysis of Brucella melitensis and Brucella canis.
- Gene expression profiling during infection of murine macrophages versus broth culture.
- Focus on genes involved in iron transport systems.
Main Results:
- Significant differences in iron transport gene transcription were observed between B. melitensis and B. canis during macrophage infection.
- The TonB, enterobactin, and ferric anguibactin transport systems showed increased transcription in B. canis, but not B. melitensis.
- These findings suggest differential iron requirements influencing bacterial intracellular survival.
Conclusions:
- Distinct iron acquisition mechanisms contribute to the differing intracellular survival strategies of B. melitensis and B. canis.
- The heightened importance of iron for B. canis early in infection may explain its specific lifestyle.
- These insights are valuable for developing control strategies against Brucella infections.
