The Role of the Ixodes scapularis Microbiome in Nutrient Provisioning To Support Its Host- Darin Shrewsberry Jr.
Ixodes scapularis is a sanguivorous ectoparasite that feeds only 3 times in its life cycle. Blood is an extremely nutrient poor food source. Many organisms in the world of obligate blood feeders partake in mutualistic relationships with bacterial endosymbionts that provision certain nutrients to them. For example: in the Tsetse/Wigglesworthia relationship, Wigglesworthia synthesizes B-Vitamins and is able to provide them to the Tsetse. The loss of this endosymbiont results in reduced fecundity in the Tseste. There is very little information regarding mutualistic endosymbionts in ticks, especially I. scapularis. Evidence suggests that REIS (Rickettsiales endosymbiont of Ixodes scapularis) possesses the ability to synthesize Biotin, however it has not been shown to possess the ability to provision it to its host. We plan to sequence the microbiome of I. scapularis to determine its metabolic capabilities to assess whether the microbiome as a whole possesses the necessary pathways for complex Vitamin B synthesis and provisioning so that we may understand how I. scapularis is able to survive solely on blood.
Biotin Acquisition of Rickettsia montanensis. - Christine Doepker.
The bacteria in the order Rickettsiales have a long history of living within host cells which has caused them to drop genes resulting in a reduced genome. This genome reduction, together with their cytosolic lifestyle, has created a relationship where Rickettsiales obtain necessary metabolic proteins and other molecules through importing or “stealing” from the host cell. Currently, I am studying how a non-pathogenic species of Rickettsia, Rickettsia montanensis, obtains biotin.
Population Genomics: Evolution of a Rickettsia buchneri population through the life cycle of host, Ixodes scapularis.
The evolution of non-pathogenic R. buchneri through host infection is unknown. We plan to utilize Multi Spacer Typing (MST) to study the short-term evolution of a population of this bacteria through the life cycle (oviposition to adulthood) of its host. This method will allow genotypes to be determined based on sequence variations within non-coding regions as opposed to coding regions due to the lack of selection pressure on these non-coding regions. The long term goal of this study is to make comparisons between non-pathogen evolution and pathogen (such as Rickettsia rickettsii) evolution through host infection.
Iron's Role in Rickettsial Infection of Eukaryotic Hosts. - Joseph Dinoto
Rickettsia are obligate intracellular pathogens that are responsible for Rocky Mountian Spotted Fever and Epidemic Typhus. A recent genomic analysis suggests that rickettsia are among the group of organisms that require iron for life. This study will focus on the role that iron plays in the ability of Rickettsia to infect eukaryotic host cells. The goal of the study is first to determine whether iron has a role in infection, and secondarily to compare the regulation of putative iron-related genes throughout the infection process.
Genetic Transfer of Bacterial DNA Between Bacteria Living Within Amoeba. -Catherine Graves
Bacteria cells in the environment are known to exchange genetic information between neighboring/surrounding bacteria. Free living amoeba are thought to be a host for intracellular bacteria, which possess the ability to survive phagocytosis and exist within the amoeba. We are investigating the types of bacteria that live within amoeba, how these genetic transfers are occurring and the relationship between these microorganisms.