Phospholipases A(2) (PLA(2)) play an important role in Toxoplasma gondii host cell penetration. They are also key enzymes in the host cell response to the parasite invasion. PLA(2) hydrolyse cellular phospholipids, releasing multiple inflammatory lipidic mediators. We have investigated the biochemical characterisation of T. gondii PLA(2) activity in a mouse-cultured tachyzoite homogenate and in the peritoneal exudate from infected mice, using the hydrolysis of a fluorescent phosphatidylglycerol labelled at the sn-2 position. Spectrofluorimetry and thin-layer chromatography showed a PLA(2) activity (about 0.5-2 nmol/min per mg), calcium-independent, secreted into infected mice peritoneal exudate, with a broad pH activity ranging between 6.5 and 9.5 and resistant to a great number of potential PLA(2) inhibitors except dithio-nitrobenzoic acid (1 mM). An associated phospholipase A(1) activity was also displayed. These results suggest that Toxoplasma gondii displays specific phospholipases different from host enzymes and probably involved at critical steps of infectious cycle.
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http://dx.doi.org/10.1016/s0020-7519(00)00101-6 | DOI Listing |
Mol Biol Cell
January 2025
LPHI, Univ. Montpellier, CNRS, INSERM, France.
Glycolysis is a conserved metabolic pathway that converts glucose into pyruvate in the cytosol, producing ATP and NADH. In and several other apicomplexan parasites, some glycolytic enzymes have isoforms located in their plastid (called the apicoplast). In this organelle, glycolytic intermediates like glyceraldehyde 3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) are imported from the cytosol and further metabolized, providing ATP, reducing power, and precursors for anabolic pathways such as isoprenoid synthesis.
View Article and Find Full Text PDFmSphere
January 2025
Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA.
Miguel Chiurillo works in the field of protein kinases, studying their role in cell signaling and cell cycle progression in . In this mSphere of Influence article, he reflects on how the research articles "Systematic functional analysis of protein kinases identifies regulators of differentiation or survival" by Baker et al. and "Screening the kinome with high throughput tagging identifies a regulator of invasion and egress" by Smith et al.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America.
The intracellular protozoan Toxoplasma gondii manipulates host cell signaling to avoid targeting by autophagosomes and lysosomal degradation. Epidermal Growth Factor Receptor (EGFR) is a mediator of this survival strategy. However, EGFR expression is limited in the brain and retina, organs affected in toxoplasmosis.
View Article and Find Full Text PDFMany inflammatory stimuli can induce progenitor cells in the bone marrow to produce increased numbers of myeloid cells as part of the process of emergency myelopoiesis. These events are associated with innate training and can have long-term impacts on hematopoietic stem and progenitor cell (HSPC) development but can also compromise their function. While many cytokines support emergency myelopoiesis, less is known about the mechanisms that temper these events.
View Article and Find Full Text PDFAust Vet J
January 2025
Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria, 3052, Australia.
Unlabelled: The southern brown bandicoot (Isoodon obesulus obesulus) is a small, endangered, Australian, ground-dwelling marsupial. Apart from isolated necropsy reports, there has not been a systematic investigation into the health and causes of death for this species.
Objective: To investigate and document the causes of death and the parasites of free-ranging populations of southern brown bandicoots in southern, central Victoria, Australia.
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