Protozoan parasites of Leishmania spp. invade macrophages as promastigotes and differentiate into replicative amastigotes within parasitophorous vacuoles. Infection of inbred strains of mice with Leishmania major is a well-studied model of the mammalian immune response to Leishmania species, but the ultrastructure and biochemical properties of the parasitophorous vacuole occupied by this parasite have been best characterized for other species of Leishmania. We examined the parasitophorous vacuole occupied by L. major in lymph nodes of infected mice and in bone marrow-derived macrophages infected in vitro. At all time points after infection, single L. major amastigotes were wrapped tightly by host membrane, suggesting that amastigotes segregate into separate vacuoles during replication. This small, individual vacuole contrasts sharply with the large, communal vacuoles occupied by Leishmania amazonensis. An extensive survey of the literature revealed that the single vacuoles occupied by L. major are characteristic of those formed by Old World species of Leishmania, while New World species of Leishmania form large vacuoles occupied by many amastigotes.
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http://dx.doi.org/10.1645/GE-841R.1 | DOI Listing |
PLoS Pathog
January 2025
LPHI, UMR 5294 CNRS/UM-UA15 Inserm, Université de Montpellier, Montpellier, France.
A sustained blood-stage infection of the human malaria parasite P. falciparum relies on the active exit of merozoites from their host erythrocytes. During this process, named egress, the infected red blood cell undergoes sequential morphological events: the rounding-up of the surrounding parasitophorous vacuole, the disruption of the vacuole membrane and finally the rupture of the red blood cell membrane.
View Article and Find Full Text PDFMicrosc Res Tech
January 2025
Department of Zoology and Entomology, Faculty of Science, Helwan University, Helwan, Egypt.
The current study provides the first ultrastructural observations on the intraerythrocytic stages of so-called Haemogregarina damiettae and their cytopathological effects on the infected erythrocytes (IEs) in addition to the recording of new morphometric data. The intraerythrocytic stages are attributed to the immature forms or trophozoites (Ts), and mature gamonts (Gs). Ts are typically bowling-bottle shaped with nucleus (TN) occupying its globose part, while Gs are typically banana- shaped.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Biochemistry and Molecular Biology, Frederick P. Whiddon College of Medicine, Mobile, AL 36688, USA.
An intracellular protozoan, the Apicomplexan parasite () infects nucleated cells, in which it triggers the formation of a specialized membrane-confined cytoplasmic vacuole, named the parasitophorous vacuole (PV). One of the most prominent events in the parasite's intracellular life is the congregation of the host cell mitochondria around the PV. However, the significance of this event has remained largely unsolved since the parasite itself possesses a functional mitochondrion, which is essential for its replication.
View Article and Find Full Text PDFExp Parasitol
December 2024
Department of Biology, Graduate Education Institute, Mardin Artuklu University, Mardin, Türkiye.
A light and electron microscopic study of skin biopsies taken from 9 patients with ulcerative leishmaniasis of both sexes aged from 14 to 26 years in the territory of the Republic of Azerbaijan was carried out. Based on clinical, morphological and electron microscopic parameters, all patients were diagnosed with ulcerative cutaneous anthroponotic leishmaniasis (Leishmania (L.) tropica).
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