Ultrastructure of schizonts and merozoites of Sarcocystis neurona.
Abstract: The ultrastructure of Sarcocystis neurona schizonts and merozoites was studied in specimens derived from cell culture and from the brains of infected mice. Schizonts and merozoites were located in the host cell cytoplasm without a parasitophorous vacuole at any stage of development. Merozoites divided by endopolygeny. Fully formed merozoites had a pellicle, numerous polysomes and ribosomes, smooth and rough endoplasmic reticulum, 22 subpellicular microtubules, 9-16 dense granules, 25-75 micronemes, a plastid, a Golgi complex, 1-3 mitochondria, a conoid, 2 apical rings, 2 polar rings, 0-6 lipid bodies, a nucleus and nucleolus, but no rhoptries. Most micronemes were located anterior to the nucleus including 1-6 micronemes in the conoid. Merozoites were either slender (7.3 microm x 1.7 microm) or stumpy (7.7 microm x 3.1 microm). Dense granules appeared to arise from the maturation face of the Golgi complex. The ultrastructure of in vitro derived schizonts and merozoites were similar to in vivo derived organisms.
Publication Date: 2001-02-27 PubMed ID: 11223206DOI: 10.1016/s0304-4017(00)00392-7Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- Non-P.H.S.
Summary
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This study explores the ultrastructure of two developmental stages (schizonts and merozoites) of the Sarcocystis neurona, a parasitic organism, using samples from lab cultures and brains of infected mice. The study reveals the parasites’ structures, their location inside the host cell, and their division process, among other features.
Overview of the Study and its Objectives
- The research focuses on surveying and detailing the ultrastructure of schizonts and merozoites, which are two developmental phases of Sarcocystis neurona, a protozoan parasite that can infect various host types, including mammals.
- By studying samples from both a laboratory culture and the brains of infected mice, the scholars offer a comprehensive overview of these parasite stages in different environments.
- The primary goal of this study is to provide more context and knowledge about this parasite’s shape, structural details, and behavior in host cells, which can act as key insights for future research and potential treatments.
Ultrastructure of Schizonts and Merozoites
- The article conveys that schizonts and merozoites of Sarcocystis neurona are situated in the host cell cytoplasm sans a parasitophorous vacuole during all development stages.
- The division of the merozoites takes place by endopolygeny, a process where one mother cell divides into multiple daughter cells.
- The fully formed merozoites possess various elements, such as a pellicle, polysomes, ribosomes, endoplasmic reticulum, several microtubules, dense granules, and micronemes. Besides, they contain a Golgi complex, mitochondria, a nucleus with a nucleolus, and lipid bodies, among others.
Sizes and Structures
- The scholars classify merozoites into two groups based on their shape and size: slender (approximately 7.3 microm x 1.7 microm) or stumpy (roughly 7.7 microm x 3.1 microm).
- The dense granules in the cell structure, which contain substances used by the parasite to infect host cells and survive, seem to come from the maturation aspect of the Golgi complex, an essential cell organelle in protein processing and transport.
Comparison of In Vivo and In Vitro Samples
- Notably, the research identifies that the ultrastructure of both in vitro (from the lab culture) and in vivo (from mice brains) derived schizonts and merozoites are alike, indicating that the development and behavior of these parasites are consistent regardless of the environment.
Cite This Article
APA
Speer CA, Dubey JP.
(2001).
Ultrastructure of schizonts and merozoites of Sarcocystis neurona.
Vet Parasitol, 95(2-4), 263-271.
https://doi.org/10.1016/s0304-4017(00)00392-7 Publication
Researcher Affiliations
- Department of Veterinary Molecular Biology, Montana State University, Bozeman 59717-3610, USA.
MeSH Terms
- Animals
- Brain / parasitology
- Cattle
- Coturnix
- Horses
- Interferon-gamma / physiology
- Mice
- Mice, Knockout
- Microscopy, Electron
- Rodent Diseases / parasitology
- Sarcocystis / ultrastructure
- Sarcocystosis / parasitology
- Sarcocystosis / veterinary
Citations
This article has been cited 10 times.- Brusini L, Dos Santos Pacheco N, Tromer EC, Soldati-Favre D, Brochet M. Composition and organization of kinetochores show plasticity in apicomplexan chromosome segregation.. J Cell Biol 2022 Sep 5;221(9).
- Attias M, Teixeira DE, Benchimol M, Vommaro RC, Crepaldi PH, De Souza W. The life-cycle of Toxoplasma gondii reviewed using animations.. Parasit Vectors 2020 Nov 23;13(1):588.
- Hammarton TC. Who Needs a Contractile Actomyosin Ring? The Plethora of Alternative Ways to Divide a Protozoan Parasite.. Front Cell Infect Microbiol 2019;9:397.
- Dubey R, Harrison B, Dangoudoubiyam S, Bandini G, Cheng K, Kosber A, Agop-Nersesian C, Howe DK, Samuelson J, Ferguson DJP, Gubbels MJ. Differential Roles for Inner Membrane Complex Proteins across Toxoplasma gondii and Sarcocystis neurona Development.. mSphere 2017 Sep-Oct;2(5).
- Dubey JP, Howe DK, Furr M, Saville WJ, Marsh AE, Reed SM, Grigg ME. An update on Sarcocystis neurona infections in animals and equine protozoal myeloencephalitis (EPM).. Vet Parasitol 2015 Apr 15;209(1-2):1-42.
- Blazejewski T, Nursimulu N, Pszenny V, Dangoudoubiyam S, Namasivayam S, Chiasson MA, Chessman K, Tonkin M, Swapna LS, Hung SS, Bridgers J, Ricklefs SM, Boulanger MJ, Dubey JP, Porcella SF, Kissinger JC, Howe DK, Grigg ME, Parkinson J. Systems-based analysis of the Sarcocystis neurona genome identifies pathways that contribute to a heteroxenous life cycle.. mBio 2015 Feb 10;6(1).
- Talevich E, Kannan N. Structural and evolutionary adaptation of rhoptry kinases and pseudokinases, a family of coccidian virulence factors.. BMC Evol Biol 2013 Jun 6;13:117.
- Ferguson DJ, Campbell SA, Henriquez FL, Phan L, Mui E, Richards TA, Muench SP, Allary M, Lu JZ, Prigge ST, Tomley F, Shirley MW, Rice DW, McLeod R, Roberts CW. Enzymes of type II fatty acid synthesis and apicoplast differentiation and division in Eimeria tenella.. Int J Parasitol 2007 Jan;37(1):33-51.
- Howe DK, Gaji RY, Mroz-Barrett M, Gubbels MJ, Striepen B, Stamper S. Sarcocystis neurona merozoites express a family of immunogenic surface antigens that are orthologues of the Toxoplasma gondii surface antigens (SAGs) and SAG-related sequences.. Infect Immun 2005 Feb;73(2):1023-33.
- Hu K, Mann T, Striepen B, Beckers CJ, Roos DS, Murray JM. Daughter cell assembly in the protozoan parasite Toxoplasma gondii.. Mol Biol Cell 2002 Feb;13(2):593-606.
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