An Insight Into the Microbial Diversity and Expression of Cysteine Protease Inhibitors (Cystatin) in <i>Rickettsia parkeri</i> Infected <i>Amblyomma maculatum</i>

<p><em>Amblyomma maculatum</em> (Gulf Coast tick) is an emerging tick species of public health significance in United States. It is a competent vector of <em>Rickettsia parkeri</em>, an etiological agent of a human rickettsiosis. In this study, we investigated the spotted fever group of rickettsial diversity in <em>A. maculatum</em> based on rickettsial <em>ompA</em> gene PCR. Our results showed <em>A. maculatum </em>harbors <em>R. parkeri, R. amblyommii, </em>and <em>R. endosymbiont of A. maculatum.</em> While only <em>R. parkeri</em> was detected in female salivary glands which suggest its ability to traffic from midgut to salivary glands via hemocoel. The presence of <em>R. parkeri</em> was further confirmed by probe based qPCR assay. We found <em>R. parkeri</em> infection rate ranged 12-40% in field collected ticks. We also provided evidence of <em>R. parkeri </em>infection transovarially and transstadially transmitted in <em>A. maculatum</em>. We used a pyrosequencing approach to further study all possible bacterial diversity residing in field collected <em>A. maculatum</em>. The huge bacterial profiling in <em>A. maculatum</em> provided the basis of Amblyomma-bacterial interactions particularly in relation to <em>R. parkeri</em>. On the other side, we observed cystatins temporal transcriptional expression in <em>A. maculatum</em>across the blood meal cycle and our finding suggested their importance during blood feeding. Further, we saw <em>R. parkeri</em> differentially regulates gene expressions of cystatins in <em>A. maculatum,</em> suggesting a possible role of cystatins in <em>R. parkeri</em> infection in ticks. This study encourages further study to assess the exact relationship of <em>R. parkeri</em> with bacterial diversity in <em>A. maculatum</em> and cystatins role during tick blood feeding and <em>R. parkeri</em> transmission.</p> <p>Link to doctoral dissertation - http://aquila.usm.edu/dissertations/1381/</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Biological Sciences

Year dc:date.available

2013

Author dc:creator

• Budachetri, Khemraj

Contributors dc:contributor

• Shahid Karim
• Mohamed Elasri
• Fengwei Bai

• Amblyomma maculatum
• gulf coast tick
• rickettsia parkeri
• spotted fever
• human rickettsiosis
• Biology
• Disorders of Environmental Origin
• Medicine and Health Sciences
• Parasitic Diseases

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/272

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1297