Parasitology Research

, Volume 73, Issue 6, pp 483–491

An ultrastructural study of the early development and tissue cyst formation of Toxoplasma gondii in the brains of mice

  • D. J. P. Ferguson
  • W. M. Hutchison
Original Investigations

Abstract

The ultrastructural features of the early development and tissue cyst formation of Toxoplasma gondii were examined in the brains of mice at various intervals from 7 days to 22 months post inoculation (PI). At 11 days PI toxoplasms, with the ultrastructural features of the proliferative (endozoite) form, were identified undergoing multiplication within both inflammatory and neural cells. Early tissue cyst formation was also observed, predominantly within neurons. By 21 days PI the proliferative forms had disappeared and only developing tissue cysts containing densely packed cystozoites were present. The proportion of dividing cystozoites decreased with increasing size and age of the cysts. The wall of the tissue cyst developed as an adaptation of the lining of the parasitophorous vacuole. In the majority of older cysts, numerous tubular structures were present beneath the cyst wall. All the cysts observed were retained within intact host cells. The only morphological change with increasing age was that a proportion of the older cysts contained loosely packed cystozoites in an electron lucent ground substance. There was no evidence of any degenerative changes within the cystozoites.

Abbreviations

C

conoid

Cy

cystozoite

D

daughter anlage

En

endozoite

HC

host cell cytoplasm

HE

host cell rough endoplasmic reticulum

HM

host cell mitochondrion

HN

host cell nucleus

M

micronene

Me

limiting membrane of parasitophorous vacuole/cyst wall

MP

micropore

MT

subpellicular microtubule

MV

microvilli

N

nucleus

NV

neurosecretory vesicle

P

polysaccharide granule

PL

pellicle

PV

parasitophorous vacuole

R

rhoptry

Ri

ribosome

S

synapse

T

tubular structure

K

vesicle

W

cyst wall

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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • D. J. P. Ferguson
    • 1
  • W. M. Hutchison
    • 2
  1. 1.Nuffield Department of PathologyUniversity of Oxford, John Radcliffe HospitalOxfordUK
  2. 2.Department of Bioscience and Biotechnology, Biology DivisionUniversity of StrathclydeGlasgowUK

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