title: An In Vitro Blood-Feeding Method Revealed Differential Borrelia turicatae (Spirochaetales: Spirochaetaceae) Gene Expression After Spirochete Acquisition and Colonization in the Soft Tick Ornithodoros turicata (Acari: Argasidae).
abstract: In the Midwestern, Southwestern, and Southern part of the United States, the soft tick Ornithodoros turicata transmits the spirochete Borrelia turicatae, the causative agent of relapsing fever in humans. In this study, we report a simplified and an efficient method of in vitro feeding to evaluate O. turicata-B. turicatae interactions. Both nymphal and adult female ticks successfully acquired spirochetes upon in vitro feeding on the B. turicatae-infected blood. We also noted transstadial transmission of spirochetes to adult ticks that were molted from nymphs fed on B. turicatae-infected blood. A differential expression pattern for some of the B. turicatae genes was evident after acquisition and colonization of the vector. The levels of arthropod-associated lipoprotein Alp-mRNA were significantly upregulated and the mRNA levels of factor H binding protein FhbA and immunogenic protein BipA were significantly downregulated in the spirochetes after acquisition into ticks in comparison with spirochetes grown in culture medium. In addition, genes such as bta124 and bta116 were significantly upregulated in spirochetes in unfed ticks in comparison with the levels noted in spirochetes after acquisition. These findings represent an efficient in vitro blood-feeding method to study B. turicatae gene expression after acquisition and colonization in these ticks. In summary, we report that B. turicatae survive and develop in the tick host when acquired by in vitro feeding. We also report that B. turicatae genes are differentially expressed in ticks in comparison with the in vitro-grown cultures, indicating influence of tick environment on spirochete gene expression.
authors.affiliation: Center for Molecular Medicine, College of Sciences, Old Dominion University, Norfolk, VA 23529 (gneelaka@odu.edu; hsultana@odu.edu ).|Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529 (dsonensh@odu.edu).
authors.forename: Girish
authors.initials: G
authors.lastname: Neelakanta
authors.affiliation: Center for Molecular Medicine, College of Sciences, Old Dominion University, Norfolk, VA 23529 (gneelaka@odu.edu; hsultana@odu.edu ).|Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529 (dsonensh@odu.edu).
authors.forename: Hameeda
authors.initials: H
authors.lastname: Sultana
authors.affiliation: Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529 (dsonensh@odu.edu).
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Sonenshine
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298 (richard.marconi@vcuhealth.org).
authors.forename: Richard T
authors.initials: RT
authors.lastname: Marconi
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001898:Borrelia / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D026861:Ornithodoros / Q000382:microbiology* / Q000502:physiology*; D012061:Relapsing Fever / Q000097:blood / Q000382:microbiology*; D013144:Spirochaetales / Q000235:genetics / Q000254:growth & development / Q000502:physiology
chemical_list: D001426:Bacterial Proteins
keywords: gene expression; relapsing fever; tick-borne disease; transstadial transmission; vector–pathogen interaction