Influence of calcium ion on host cell invasion and intracellular replication by Toxoplasma gondii
2
조회
0
다운로드
7
인용
0
참고문헌
초록
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite, which invades a wide range of hosts including humans. The exact mechanisms involved in its invasion are not fully understood. This study focused on the roles of Ca2+ in host cell invasion and in T. gondii replication. We examined the invasion and replication of T. gondii pretreated with several calcium modulators, the conoid extrusion of tachyzoites. Calmodulin localization in T. gondii were observed using the immunogold method, and Ca2+ levels in tachyzoites by confocal microscopy. In light microscopic observation, Tachyzoites co-treated with A23187 and EGTA showed that host cell invasion and intracellular replication were decreased. The invasion of tachyzoites was slightly inhibited by the Ca2+ channel blockers, bepridil and verapamil, and by the calmodulin antagonist, calmidazolium. We observed that calcium saline containing A23187 induced the extrusion of tachyzoite conoid. By immunoelectron microscopy, gold particles bound to anti-calmodulin or anti-actin mAb, were found to be localized on the anterior portions of tachyzoites. Remarkably reduced intracellular Ca2+ was observed in tachyzoites treated with BAPTA/AM by confocal microscopy. These results suggest that host cell invasion and the intracellular replication of T. gondii tachyzoites are inhibited by the calcium ionophore, A23187, and by the extracellular calcium chelator, EGTA.
참고문헌 (26)
- "Ionophore-resistant mutants of Toxoplasma gondii reveal host cell permeabilization as an early event in egress", 20, pp.9399~9408 (2000)
- "Agonist-releasable intracellular calcium stores and the phenomenon of store-dependent calcium entry. A novel hypothesis based on calcium stores in organelles of the endo- and exocytotic apparatus", 51, pp.993~1001 (1996)
- "Signaling during the invasion of host cells by Toxoplasma gondii", 23, pp.551~561 (1999)
- "Calmodulin plays a pivotal role in cellular regulation", pp.~207
- "Structures of Toxoplasma gondii tachyzoites and sporozoites and biology and development of tissue cysts", 11, pp.267~299 (1998)
- "Strategies of obligate intracellular parasites for evading host defences", immu(l today 12), pp.22~27 (1991)
- "582 inhibition of intracellular parasitic protozoal growth correlates with host-cell directed effects", pp.462~651 467 (1991)
- "Role of cytoskeleton in host Cell invasion by intracellular protozoa Toxoplasma gondii", 12, pp.628~634 (2002)
- "Toxoplasmic encephalitis in AIDS", pp.211~222 (1992)
- "Effect of calcium antagonists calcium channel blockers and calmodulin inhibitors on the growth and encystation of Entamoeba histolytica and E. invadens", 87, pp.833~837 (2001)
- "Role of calmodulin in Plasmodium falciparum implications for erythrocyte invasion by the merozoite", pp.36~43 (1987)
- "Ca2+-dependence of conoid extrusion in Toxoplasma gondii tachyzoites", 43, pp.120~127 (1996)
- "Calcium regulation in protozoan parasites", 6, pp.359~364 (2003)
- "Acidocalcisomes in Toxoplasma gondii tachyzoites", 15, pp.655~659 (1996)
- "Invasion of Toxoplasma gondii occurs by active penetration of the host cell", 108, pp.2457~2464 (1995)
- "The loss of cytoplasmic potassium upon host cell breakdown triggers egress of Toxoplasma gondii", 276, pp.41492~41501 (2001)
- "Cytoskeleton of Toxoplasma gondii", chiappi(ml), pp.217~226 (1987)
- "Calmodulin distribution and the actomyosin cytoskeleton in Toxoplasma gondii", 49, pp.445~454 (2001)
- "Involvement of calcium and calmodulin in Toxoplasma gondii tachyzoite invasion", 74, pp.92~101 (1997)
- "Regulation of intracellular calcium in promastigotes of the human protozoan parasite Leishmania donovani", pp.10420~10424 (1989)
- "Relationship between intracellular free calcium concentrations and the intracellular development of Toxoplasma gondii", 44, pp.1123~1129 (1996)
- "Calcium-dependent protein phosphorylation in Babesia bovis and its role in growth regulation", pp.153~161 (1990)
- "purine synthesis and salvage in mutant host cells and parasites", pp.77~86 (1982)
- "Mobilization of intracellular calcium upon attachment of Toxoplasma gondii tachyzoites to human fibroblasts is required for invasion", 106, pp.157~162 (2000)
- "Biology of Toxoplasma gondii", pp.299~7 316 (1993)
- "Changes in Trypanosoma cruzi infectivity by treatments that affect calcium ion levels", pp.119~125 (1994)
