Kazal Serine Protease Inhibitors and their Role in Prototheca wickerhamii Pathogenicity

Kazal Serine Protease Inhibitors and their Role in Prototheca wickerhamii Pathogenicity

Several genes are known to be involved in pathogenic processes. Among these, Kazal serine protease inhibitors (InterPro IPR002350) have been shown to be recurrently used by pathogenic eukaryotes. Kazal serine protease inhibitors are involved in the pathogenicity of Plasmodium falciparum by providing protection to parasitic proteins from the host’s defenses. Although Kazal protease inhibitors have been associated with the pathogenicity of several eukaryotic microbes, it is unclear if they are involved in Prototheca wickerhamii infection. Prototheca wickerhamii is an achlorophyllic green alga known to cause infections in humans. Olecranon bursitis, cutaneous, and bilateral choroiditis are three types of clinical infections resulting from this facultative pathogen in immunosuppressed hosts. Over one-third of the reported cases advanced to systemic dissemination, some eventually led to death. The main objective of this study was to sequence Kazal-like protease inhibitor genes from Prototheca wickerhamii and estimate the role of these proteins in the pathogenic process. Prototheca wickerhamiihas been successfully cultured and cells collected were used for DNA extraction. Although Kazal-like protease inhibitor genes have yet to be sequenced, preliminary sequence analyses performed on 18S rDNA and β-tubulin genes revealed that two strains classified as Prototheca wickerhamii might have been erroneously identified and may be better represented by establishing a new genus (Pseudoprototheca gen. nov.). These findings are crucial to establish a clear taxonomic framework for the identification of emerging pathogens. Additional studies will be directed towards the expression of Kazal and its involvement in pathogenicity.