124 research outputs found
SAS6-like protein in Plasmodium indicates that conoid-associated apical complex proteins persist in invasive stages within the mosquito vector
The SAS6-like (SAS6L) protein, a truncated paralogue of the ubiquitous basal body/centriole protein SAS6, has been characterised recently as a flagellum protein in trypanosomatids, but associated with the conoid in apicomplexan Toxoplasma. The conoid has been suggested to derive from flagella parts, but is thought to have been lost from some apicomplexans including the malaria-causing genus Plasmodium. Presence of SAS6L in Plasmodium, therefore, suggested a possible role in flagella assembly in male gametes, the only flagellated stage. Here, we have studied the expression and role of SAS6L throughout the Plasmodium life cycle using the rodent malaria model P. berghei. Contrary to a hypothesised role in flagella, SAS6L was absent during gamete flagellum formation. Instead, SAS6L was restricted to the apical complex in ookinetes and sporozoites, the extracellular invasive stages that develop within the mosquito vector. In these stages SAS6L forms an apical ring, as we show is also the case in Toxoplasma tachyzoites. The SAS6L ring was not apparent in blood-stage invasive merozoites, indicating that the apical complex is differentiated between the different invasive forms. Overall this study indicates that a conoid-associated apical complex protein and ring structure is persistent in Plasmodium in a stage-specific manner
A Novel Family of Toxoplasma IMC Proteins Displays a Hierarchical Organization and Functions in Coordinating Parasite Division
Apicomplexans employ a peripheral membrane system called the inner membrane complex (IMC) for critical processes such as host cell invasion and daughter cell formation. We have identified a family of proteins that define novel sub-compartments of the Toxoplasma gondii IMC. These IMC Sub-compartment Proteins, ISP1, 2 and 3, are conserved throughout the Apicomplexa, but do not appear to be present outside the phylum. ISP1 localizes to the apical cap portion of the IMC, while ISP2 localizes to a central IMC region and ISP3 localizes to a central plus basal region of the complex. Targeting of all three ISPs is dependent upon N-terminal residues predicted for coordinated myristoylation and palmitoylation. Surprisingly, we show that disruption of ISP1 results in a dramatic relocalization of ISP2 and ISP3 to the apical cap. Although the N-terminal region of ISP1 is necessary and sufficient for apical cap targeting, exclusion of other family members requires the remaining C-terminal region of the protein. This gate-keeping function of ISP1 reveals an unprecedented mechanism of interactive and hierarchical targeting of proteins to establish these unique sub-compartments in the Toxoplasma IMC. Finally, we show that loss of ISP2 results in severe defects in daughter cell formation during endodyogeny, indicating a role for the ISP proteins in coordinating this unique process of Toxoplasma replication
Response of emergent macrophytes to hydrological changes in a shallow lake, with special reference to nutrient cycling
Water nutrient concentrations in channels in relation to occurrence of aquatic plants: a case study in eastern Croatia
Development of comprehensive river typology based on macrophytes in the mountain-lowland gradient of different Central European ecoregions
Delayed infection of a pelvic lymphocele following robotic radical prostatectomy and pelvic lymphadenectomy: two cases
Osteogenic differentiation of adipose‐derived stem cells prompted by low‐intensity pulsed ultrasound
Intraurethral Imiquimod for Extensive Urethral Genital Warts (Condylomata Acuminata)
We present the case of a 55 year old patient under immunosuppressive treatment who developed multiple anogenital condylomata acuminata. Urethroscopy showed extensive condylomatous involvement of the entire penile urethra. Due to the potential morbidity of any surgical approach, we opted for an experimental treatment with Imiquimod (250 mg 5%-Imiquimod intraurethrally 3 times weekly), which was well tolerated. After a remarkable initial response and a continuous decline in the number of lesions, only minimal residual condylomata were left after 15 months. These were resected with the Holmium:YAG laser. Follow-up urethroscopy at three months showed no recurrence or signs of urethral stricture
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