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Tag: Dennis Kyle

First evidence of polychaete intermediate hosts for Neospirorchis spp. marine turtle blood flukes (Trematoda: Spirorchiidae)


Graphical abstract

Life cycles of spirorchiids that infect the vascular system of turtles are poorly understood. Few life cycles of these blood flukes have been elucidated and all intermediate hosts reported are gastropods (Mollusca), regardless of whether the definitive host is a freshwater or a marine turtle. During a recent survey of blood fluke larvae in polychaetes on the coast of South Carolina, USA, spirorchiid-like cercariae were found to infect the polychaetes Amphitrite ornata (Terebellidae) and Enoplobranchus sanguineus (Polycirridae). Cercariae were large, furcate, with a ventral acetabulum, but no eyespots were observed. Partial sequences of D1–D2 domains of the large ribosomal subunit, the internal transcribed spacer 2, and the mitochondrial cytochrome oxidase 1 genes allowed the identification of sporocysts and cercariae as belonging to two unidentified Neospirorchis species reported from the green turtle, Chelonia mydas, in Florida: Neospirorchis sp. (Neogen 13) in A. ornata and Neospirorchis sp. (Neogen 14) in E. sanguineus. Phylogenetic analysis suggests that infection of annelids by blood flukes evolved separately in aporocotylids and spirorchiids. Our results support the contention that the Spirorchiidae is not a valid family and suggest that Neospirorchis is a monophyletic clade within the paraphyletic Spirorchiidae. Since specificity of spirorchiids for their intermediate hosts is broader than it was thus far assumed, surveys of annelids in turtle habitats are necessary to further our understanding of the life history of these pathogenic parasites.

Isaure de Buron, Beatrice L. Colon, Sasha V. Siegel, Jenna Oberstaller, Andrea Rivero, Dennis E. Kyle. 2018. International Journal for Parasitology; 48(14):1097-1106.

Phenotypic screens reveal posaconazole as rapidly cidal combination partner for treatment of Primary Amoebic Meningoencephalitis


Naegleria fowleri is the causative agent of primary amoebic meningoencephalitis (PAM), which is fatal in >97% of cases. In this study, we aimed to identify new, rapidly acting drugs to increase survival rates. We conducted phenotypic screens of libraries of Food and Drug Administration–approved compounds and the Medicines for Malaria Venture Pathogen Box and validated 14 hits (defined as a 50% inhibitory concentration of <1 μM). The hits were then prioritized by assessing the rate of action and efficacy in combination with current drugs used to treat PAM. Posaconazole was found to inhibit amoeba growth within the first 12 hours of exposure, which was faster than any currently used drug. In addition, posaconazole cured 33% of N. fowleri–infected mice at a dose of 20 mg/kg and, in combination with azithromycin, increased survival by an additional 20%. Fluconazole, which is currently used for PAM therapy, was ineffective in vitro and vivo. Our results suggest posaconazole could replace fluconazole in the treatment of PAM.

Beatrice L Colon, Christopher A Rice, R Kiplin Guy, Dennis E Kyle. 2018. The Journal of Infectious Diseases.

A recombinant antibody against Plasmodium vivax UIS4 for distinguishing replicating from dormant liver stages


Background:Plasmodium vivax is the most geographically widespread of the human malaria parasites, causing 50,000 to 100,000 deaths annually. Plasmodium vivax parasites have the unique feature of forming dormant liver stages (hypnozoites) that can reactivate weeks or months after a parasite-infected mosquito bite, leading to new symptomatic blood stage infections. Efforts to eliminate P. vivax malaria likely will need to target the persistent hypnozoites in the liver. Therefore, research on P. vivax liver stages necessitates a marker for clearly distinguishing between actively replicating parasites and dormant hypnozoites. Hypnozoites possess a densely fluorescent prominence in the parasitophorous vacuole membrane (PVM) when stained with antibodies against the PVM-resident protein Upregulated in Infectious Sporozoites 4 (PvUIS4), resulting in a key feature recognizable for quantification of hypnozoites. Thus, PvUIS4 staining, in combination with the characteristic small size of the parasite, is currently the only hypnozoite-specific morphological marker available.

Results: Here, the generation and validation of a recombinant monoclonal antibody against PvUIS4 (α-rUIS4 mAb) is described. The variable heavy and light chain domains of an α-PvUIS4 hybridoma were cloned into murine IgG1 and IgK expression vectors. These expression plasmids were co-transfected into HEK293 cells and mature IgG was purified from culture supernatants. It is shown that the α-rUIS4 mAb binds to its target with high affinity. It reliably stains the schizont PVM and the hypnozoite-specific PVM prominence, enabling the visual differentiation of hypnozoites from replicating liver stages by immunofluorescence assays in different in vitro settings, as well as in liver sections from P. vivax infected liver-chimeric mice. The antibody functions reliably against all four parasite isolates tested and will be an important tool in the identification of the elusive hypnozoite.

Conclusions: The α-rUIS4 mAb is a versatile tool for distinguishing replicating P. vivax liver stages from dormant hypnozoites, making it a valuable resource that can be deployed throughout laboratories worldwide.

Carola Schafer, Nicholas Dambrauskas, Ryan W. Steel, Sara Carbonetti, Vorada Chuenchob, Erika L. Flannery, Vladimir Vigdorovich, Brian G. Oliver, Wanlapa Roobsoong, Steven P. Maher, Dennis Kyle, Jetsumon Sattabongkot, Stefan H. I. Kappe, Sebastian A. Mikolajczak and D. Noah Sather. 2018. Malaria Journal; 17:370.

Trainee Spotlight: Beatrice Colon

trainee Beatrice Colon

Beatrice Colon, an Illinois native, is a Ph.D. trainee in Dennis Kyle’s laboratory. She holds a Bachelor of Science degree from the University of Illinois at Urbana-Champaign and a Master of Science degree from the University of South Florida (USF). She began her Ph.D. at USF as well.

Beatrice moved to the University of Georgia in January 2017 with the Kyle Lab.

“I decided to transfer universities because of the excellent infectious disease department,” said Beatrice.

Research and Training

“My favorite thing about the CTEGD is the openness for collaborations; the center is also very focused on training a new generation of scientists. “

Beatrice is currently working on a drug discovery project for the brain-eating amoeba, Naegleria fowleri. The disease was the major factor that drew her to the project. Primary amoebic meningoencephalitis is nearly always fatal and affects young healthy children. Moreover, there is not an effective drug treatment for people that do get infected with the amoeba.

In her short time at UGA, Beatrice has won first place for a poster presentation at the graduate student and postdoc symposium. She was also selected for the Biology of Parasitism course at Woods Hole, MA this past summer.

“This course was definitely a career-changing experience – I was able to work with a variety of infectious diseases and learn techniques that were not available for the parasite I work on.”

What’s Next

Beatrice is interested in staying in drug discovery for infectious diseases and currently looking at positions in both academia and industry.


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