Characterization and immunolocalization of a main proteinaceous component of the cell wall of the protozoan parasite Perkinsus atlanticus

Abstract

Described in the present study is a major component of the cell wall of 2 of the most pathogenic parasites of molluscs, Perkinsus atlanticus and P. marinus. The component is a high molecular weight protein (233 kDa), which we have named PWP-1 (for Perkinsus wall protein-1). Western blots, using a polyclonal serum generated against purified PWP-1 from P. atlanticus, revealed that this protein is expressed by all walled developmental stages of this protozoon. By means of immunogold electron microscopy, labelling for PWP-1 was strong and specifically associated with the cell wall. The label density and distribution pattern was quite different between trophozoites and prezoosporangia. With regard to the structural organization of this protein, PWP-1 is disulphide-linked to other cell wall components and released from the cell wall only following treatment with a sulphydryl agent. We also report that PWP-1 is a trypsin-resistant protein, both in its native and heat-denatured conformation. In addition, results from the N-terminal microsequence of this protein allow us to define PWP-1 as a novel cell wall protein. Overall, our findings strongly suggest that PWP-1 plays a key role in the organization of the cell wall of these protozoa, promoting their survival.

CRISPR/Cas9 Ribonucleoprotein-Based Genome Editing Methodology in the Marine Protozoan Parasite Perkinsus marinus

“…Additionally, the rhoptry proteins such as serine-threonine kinases, protein phosphatases, proteosomes, and a virulent candidate merozoite surface protein 3, which are known to play a crucial role in parasite invasion and cell-cell communication during the invasion in P. falciparum were also identified in P. marinus. Studies so far reported that P. marinus possess extracellular proteins such as high molecular weight cell wall protein 1 (Montes et al, 2002); glycosylation, mucin, and sugar-binding domain protein Pmar_XP_002783417.1 encoded by Pmar_PMAR006943; sensory signal transduction-related histidine kinase encoded by Pmar_PMAR009211; and a family of cysteine-rich modular proteins whose function in the parasite life cycle are yet to be investigated (Montes et al, 2002). Furthermore, apoptotic genes such as apoptosis inhibitory molecule (Fas), apoptosis-inducing factor (Tadesse et al, 2017;Lau et al, 2018b), peroxiredoxin, and superoxide dismutase are shown to favor parasite survival by reducing the host cell Box et al, 2020).…”

Diversity of extracellular proteins during the transition from the ‘proto-apicomplexan’ alveolates to the apicomplexan obligate parasites

“…Apicomplexans which do not have an externally shed oocyst stage have lost OWP genes; such as Plasmodium, Babesia and Theileria. Perkinsus lacks OWP genes and also does not possess a durable cyst stage; with only one report describing an apparently abundant 'cell wall' protein which is probably unrelated to cyst walls (Montes et al 2002). The observation that OWP proteins are present in proto-apicomplexans provides markers with which to describe the great diversity in structures of inner and outer cell walls in the alveolates.…”

Perkinsosis in molluscs: A review

“…Polyclonal antisera specific against polypeptides obtained from P. olseni/P. atlanticus hypnospores have been produced by Montes et al (2002).…”