Last data update: Sep 16, 2024. (Total: 47680 publications since 2009)
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Query Trace: Galletti Mfbm [original query] |
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Applying MALDI-TOF MS to resolve morphologic and genetic similarities between two Dermacentor tick species of public health importance
Galletti Mfbm , Hecht JA , McQuiston JR , Gartin J , Cochran J , Blocher BH , Ayres BN , Allerdice MEJ , Beati L , Nicholson WL , Snellgrove AN , Paddock CD . Sci Rep 2024 14 (1) 19834 Hard ticks (Acari: Ixodidae) have been historically identified by morphological methods which require highly specialized expertise and more recently by DNA-based molecular assays that involve high costs. Although both approaches provide complementary data for tick identification, each method has limitations which restrict their use on large-scale settings such as regional or national tick surveillance programs. To overcome those obstacles, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been introduced as a cost-efficient method for the identification of various organisms, as it balances performance, speed, and high data output. Here we describe the use of this technology to validate the distinction of two closely related Dermacentor tick species based on the development of the first nationwide MALDI-TOF MS reference database described to date. The dataset obtained from this protein-based approach confirms that tick specimens collected from United States regions west of the Rocky Mountains and identified previously as Dermacentor variabilis are the recently described species, Dermacentor similis. Therefore, we propose that this integrative taxonomic tool can facilitate vector and vector-borne pathogen surveillance programs in the United States and elsewhere. |
Isolate-dependent differences in clinical, pathological, and transcriptional profiles following in vitro and in vivo infections with Rickettsia rickettsii .
Galletti MFBM , Paddock CD , Hecht JA , Biggerstaff BJ , Ritter JM , Karpathy SE . Infect Immun 2021 89 (4) Rickettsia rickettsii, the etiological agent of Rocky Mountain spotted fever (RMSF), a life-threatening tick-borne disease that affects humans and various animal species, has been recognized in medicine and science for more than 100 years. Isolate-dependent differences in virulence of R. rickettsii have been documented for many decades; nonetheless, the specific genetic and phenotypic factors responsible for these differences have not been characterized. Using in vivo and in vitro methods, we identified multiple phenotypic differences among six geographically distinct isolates of R. rickettsii, representing isolates from the United States, Costa Rica, and Brazil. Aggregate phenotypic data, derived from growth in Vero E6 cells and from clinical and pathological characteristics following infection of male guinea pigs (Cavia porcellus), allowed separation of these isolates into three categories: non-virulent (Iowa); mildly virulent (Sawtooth and Gila), and highly virulent (Sheila Smith(T), Costa Rica, and Taiaçu). Transcriptional profiles of 11 recognized or putative virulence factors confirmed the isolate-dependent differences between a mildly and a highly virulent isolate. These data corroborate previous qualitative assessments of strain virulence and suggest further that a critical and previously underappreciated balance between bacterial growth and host immune response could leverage strain pathogenicity. Also, this work provide insight into isolate-specific microbiological factors that contribute to the outcome of RMSF and confirms the hypothesis that distinct rickettsial isolates also differ phenotypically, which could influence the severity of disease in vertebrate hosts. |
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