Structures of<i>Toxoplasma gondii</i>Tachyzoites, Bradyzoites, and Sporozoites and Biology and Development of Tissue Cysts

Dubey, J. P.; Lindsay, David S.; Speer, Clarence A.

doi:10.1128/cmr.11.2.267

Cited by 992 publications

(867 citation statements)

References 143 publications

(204 reference statements)

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“…The observation that nonencysted stages in the skeletal muscles, tongue, and diaphragm exhibit bradyzoite markers is surprising. In vitro studies with T. gondii indicate that the BAG-5 antigen is an early developing bradyzoite marker (Dubey et al 1998b). Therefore, stages expressing the BAG-5 antigen might not be fully mature bradyzoites.…”

Section: Discussionmentioning

confidence: 99%

Canine neosporosis: clinical and pathological findings and first isolation of Neospora caninum in Germany

2000

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Neosporosis was diagnosed in an 11-week-old puppy of the breed Kleiner Münsterländer with progressive hindlimb paresis. Pathohistological and immunohistological examinations revealed a disseminated infection with Neospora caninum. Parasitic stages were demonstrated in the brain, spinal cord, retina, muscles, thymus, heart, liver, kidney, stomach, adrenal gland, and skin. Immunohistochemistry investigations were carried out using polyclonal rabbit antisera developed against N. caninum tachyzoites and the recombinant bradyzoite-specific antigen BAG-5 of Toxoplasma gondii, which is known to cross-react with N. caninum bradyzoites. BAG-5 antibodies recognized tissue cysts within the CNS and some protozoan stages that were not surrounded by a visible cyst wall. All parasite clusters in the retina and some in muscle tissue stained positively with the BAG-5 antiserum. N. caninum was isolated in cell culture and mice inoculated with brain and spinal cord of the puppy. The new isolate is the first reported in Germany and is designated NC-GER1.

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Section: Discussionmentioning

confidence: 99%

Canine neosporosis: clinical and pathological findings and first isolation of Neospora caninum in Germany

2000

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“…Concerning other developmental stages of T. gondii (for review, see Dubey et al 1998), the presence of an OMC complex has not been explicitly determined yet. Nondividing bradyzoites, strain ME49, which were purified from the brains of mice 2 months after infection, failed to reveal such structure (data not shown).…”

Section: Discussionmentioning

confidence: 99%

“…Both the parasite's proliferating tachyzoite form and the slowly dividing bradyzoite stage were shown to possess a relatively characteristic mitochondrial ultrastructure including a dualmembraned wall with vesicular cristae permeating a substantial matrix space (van der Zypen and Piekarski 1967; Dubey et al 1998). However, serial-sectioned T. gondii tachyzoites recently prepared to analyze the apicoplast (Köhler 2005), a plastid-like organelle of Apicomplexa, strongly suggested that T. gondii tachyzoites might also possess a greater diversity regarding its mitochondrial architecture as presently discussed.…”

Section: Introductionmentioning

confidence: 98%

Multi-membrane-bound structures of Apicomplexa: II. the ovoid mitochondrial cytoplasmic (OMC) complex of Toxoplasma gondii tachyzoites

Köhler

2006

Parasitol Res

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Apicomplexa including the causative agents of toxoplasmosis and malaria reportedly possess one or few tubular-shaped mitochondria that permeate, more or less branched, throughout these unicellular parasites. Electron micrographs generated herein from serial-sectioned Toxoplasma gondii tachyzoites demonstrated, however, a greater diversity regarding both the shape of the cultured parasite's single mitochondrion and its sub-structural organization. Moreover, a unique subcellular construction was detected that basically comprised a pouch-shaped subdivision of the tachyzoite mitochondrion plus a fraction of parasitic cytoplasm enclosed therein. This composite assembling, termed ovoid mitochondrial cytoplasmic (OMC) complex, characteristically displayed a highly reduced matrix lumen of its mitochondrial border construction, which furthermore often failed to possess any cristae or contained tightly pleated cristae, thus creating a pouch-shaped multi-laminar wall of four or more membranous layers, respectively. Given this architecture, cross-sectioned OMC complexes of T. gondii tachyzoites frequently mimicked in size and shape the parasites' plastid-like organelle (apicoplast). Moreover, like the apicoplast, the OMC complex was often found adjacent to the tachyzoite's single Golgi complex and constantly located in close proximity to the outer membrane of the parasite's nuclear envelope. The T. gondii OMC complex differed, however, from the apicoplast in its exact fine structural organization and a stage-restricted presence that was apparently linked to mitochondrial growth and/or division. Any special function(s) possibly performed by the T. gondii OMC complex remains, nevertheless, to be elucidated.

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“…T. gondii has various infectious stages that have a similar ultrastructure but dier in the rhoptries (Dubey et al 1998). Accumulating evidence indicates that a vaccine of stage-speci®c antigen leads stage-limited protection (reviewed by Alexander et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Recombinant feline herpesvirus type 1 expressing Toxoplasma gondii ROP2 antigen inducible protective immunity in cats

Mishima

Yokoyama

et al. 2002

Parasitol Res

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In order to investigate whether a recombinant viral vaccine composed of a feline herpesvirus type 1 (FHVI) vector and an immunogenic antigen of Toxoplasma gondii can induce a protective immunity in cats, a recombinant FHV1 expressing ROP2 antigen of T. gondii was prepared. We introduced a DNA fragment encoding 1-538 amino acid residues of ROP2 precursor into FHV1 genome under the control of a cytomegalovirus promoter. The recombinant FHV1 (FHV/ROP2) successfully expressed a 59 kDa antigen that was recognized by anti-ROP2 antibodies. Vaccination of cats with FHV/ROP2 induced serum IgG recognizing the native antigen. Moreover the antibodies inhibited the in vitro invasion of tachyzoites. The vaccination also accelerated the IgG response after T. gondii infection and reduced brain parasite load in cats.

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Structures ofToxoplasma gondiiTachyzoites, Bradyzoites, and Sporozoites and Biology and Development of Tissue Cysts

Cited by 992 publications

References 143 publications

Canine neosporosis: clinical and pathological findings and first isolation of Neospora caninum in Germany

Canine neosporosis: clinical and pathological findings and first isolation of Neospora caninum in Germany

Multi-membrane-bound structures of Apicomplexa: II. the ovoid mitochondrial cytoplasmic (OMC) complex of Toxoplasma gondii tachyzoites

Recombinant feline herpesvirus type 1 expressing Toxoplasma gondii ROP2 antigen inducible protective immunity in cats

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