Selected Grantee Publications
Whole-Genome Sequences of Six Borrelia recurrentis Strains Obtained via PacBio Sequencing
Gaber et al., Microbiology Resource Announcements. 2025.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11895452
The spirochetal bacterium Borrelia recurrentis causes louse-borne relapsing fever (LBRF), which leads to significant morbidity and mortality in several African countries. Previous sequencing studies of B. recurrentis demonstrated discrepancies and did not accurately define the antigenic variation system. In this study, researchers used long-read PacBio technology to conduct whole-genome sequencing of six B. recurrentis strains that had been isolated from LBRF patients earlier. The resulting sequences of each genome included one linear chromosome and five linear plasmids, whose average size was 1,284,895 bp, with the mean GC content being 27.5%. Supported by ORIP (T32OD011083) and NIAID.
Quorum Sensing LuxR Proteins VjbR and BabR Jointly Regulate Brucella abortus Survival During Infection
Caudill et al., Journal of Bacteriology. 2025.
https://pubmed.ncbi.nlm.nih.gov/40013834
Brucella abortus is a zoonotic bacterial pathogen that causes brucellosis, a persistent chronic infection that is globally endemic. B. abortus uses quorum sensing to escape immune clearance attempts, regulate virulence, and cause persistent infection within hosts. B. abortus quorum sensing system comprises two LuxR proteins, VjbR and BabR, as well as two signals, dodecanoyl (C12 AHL) and 3-oxododecanoyl (3-OXO-C12 AHL) homoserine lactone. Using chronic infection 6- to 7-week-old C57Bl/6 and BALB/c male and female mouse models, researchers found that the ΔvjbRΔbabR double-deletion strain was attenuated compared with single mutants. These results demonstrate that both quorum sensing proteins, VjbR and BabR, coordinate to maintain survival. This study helps further characterize the Brucella quorum sensing systems and indicates that further attention should be given to the joint interactions between VjbR and BabR in controlling virulence. Supported by ORIP (T32OD028239) and NIAID.
Time of Sample Collection Is Critical for the Replicability of Microbiome Analyses
Allaband et al., Nature Metabolism. 2024.
https://pubmed.ncbi.nlm.nih.gov/38951660/
Lack of replicability remains a challenge in microbiome studies. As the microbiome field moves from descriptive and associative research to mechanistic and interventional studies, being able to account for all confounding variables in the experimental design will be critical. Researchers conducted a retrospective analysis of 16S amplicon sequencing studies in male mice. They report that sample collection time affects the conclusions drawn from microbiome studies. The lack of consistency in the time of sample collection could help explain poor cross-study replicability in microbiome research. The effect of diurnal rhythms on the outcomes and study designs of other fields is unknown but is likely significant. Supported by ORIP (T32OD017863), NCATS, NCI, NHLBI, NIAAA, NIAID, NIBIB, NIDDK, and NIGMS.
Interferon Regulatory Factor 7 Modulates Virus Clearance and Immune Responses to Alphavirus Encephalomyelitis
Troisi et al., Journal of Virology. 2023.
https://pubmed.ncbi.nlm.nih.gov/37772825/
Interferon regulatory factor 7 (IRF7)–deficient mice develop fatal paralysis after CNS infection with Sindbis virus, while wild-type mice recover. Irf7-/- mice produce low levels of IFN-α but high levels of IFN-β with induction of IFN-stimulated genes, so the reason for this difference is not understood. The current study shows that Irf7-/- mice developed inflammation earlier but failed to clear virus from motor neuron–rich regions of the brainstem and spinal cord. Therefore, IRF7 is either necessary for the neuronal response to currently identified mediators of clearance or enables the production of additional antiviral factor(s) needed for clearance. Supported by ORIP (T32OD011089, R01OD01026529) NINDS, and NIAID.
Innate Lymphoid Cells and Interferons Limit Neurologic and Articular Complications of Brucellosis
Moley et al., American Journal of Pathology. 2023.
https://www.sciencedirect.com/science/article/pii/S0002944023001980?via%3Dihub=
Brucellosis is a globally significant zoonotic disease. The current study investigated the role of innate lymphoid cells (ILCs) in the pathogenesis of focal brucellosis caused by Brucella melitensis. Following pulmonary infection with B. melitensis, mice lacking adaptive immune cells and ILCs developed arthritis, neurologic complications, and meningitis. Transcriptional analysis of Brucella-infected brains revealed marked upregulation of genes associated with inflammation and interferon responses. Collectively, these findings indicate that ILCs and interferons play an important role in prevention of focal complications during Brucella infection and that mice with deficiencies in ILCs or interferons can be used to study pathogenesis of neurobrucellosis. Supported by ORIP (T32OD011126) and NIAID.
The Incompetence of Mosquitoes—Can Zika Virus Be Adapted to Infect Culex tarsalis Cells?
Gallichotte et al., mSphere . 2023.
Zika virus (ZIKV) is transmitted between humans by Aedes aegypti mosquitoes. However, the 2015 to 2017 outbreak raised questions regarding the role of Culex species mosquitoes in transmission. Investigators attempted to adapt ZIKV to C. tarsalis by serially passaging the virus on cocultured A. aegypti and C. tarsalis cells to identify viral determinants of species specificity. Next-generation sequencing of cocultured virus passages revealed variants of interest that were engineered into nine recombinant viruses. None of these viruses showed increased infection of Culex cells or mosquitoes. Thus, although ZIKV might infect Culex mosquitoes occasionally, Aedes mosquitoes likely drive transmission and human risk. Supported by ORIP (T32OD010437) and NIAID.