Electronic cytochemical demonstration of a lysosome in Leishmania donovani

McAlpine, J. C.

doi:10.1016/0035-9203(70)90099-4

Cited by 11 publications

(4 citation statements)

References 7 publications

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“…Since Leishmania amastigotes lodge within acidified vacuoles and the parasites themselves are endowed with lysosomes (21,22), we postulated that amino acid esters accumulated in the p.v. could be further concentrated in the amastigote lysosomes, leading to damage to the parasites.…”

mentioning

confidence: 99%

Destruction of Leishmania mexicana amazonensis amastigotes within macrophages by lysosomotropic amino acid esters.

Rabinovitch¹,

Zilberfarb²,

Ramazeilles³

1986

The Journal of Experimental Medicine

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Leishmania amastigotes parasitize almost exclusively the mononuclear phagocytes of mammals. The organisms survive and multiply within acidified vacuoles (parasitophorous vacuoles; p.v.) akin to phagolysosomes. Certain amino acid esters are known to accumulate in and disrupt lysosomes. We postulated that, since Leishmania possess lysosome-like organelles, they may be susceptible to the potentially high ester concentrations attained in the p.v. We report here that L-amino acid esters can rapidly destroy intracellular Leishmania at concentrations that do not appear to damage the host cells. L-leu-OMe, which cured greater than or equal to 90% of infected macrophages at 0.8 mM concentrations, was used in most of the experiments. L-leu-OMe was only active after infection, implying inefficient transfer from secondary lysosomes to the p.v. Parasite destruction had several features in common with lysosomal and leukocyte damage induced by the esters, i.e., inactivity of D-amino acid esters, a marked pH dependence and increased killing after ester pulses at lower temperatures. Killing depended on the amino acid and on the ester substitution. The most active of the methyl esters assayed was that of leucine, followed by those of tryptophan, glutamic acid, methionine, phenylalanine, and tyrosine. Methyl esters of seven other amino acids were inactive when tested at up to 10 mM concentrations. Among leucine esters studied, benzyl ester was sixfold more active than the methyl homolog. The dipeptide L-leu-leu-OMe produced 90% cure at 0.08 mM concentrations. Leishmanicidal activity could be related to penetration of the parasites by the esters or to toxic ester hydrolysis products released in the p.v. The first hypothesis is supported by the pH-dependent destruction of isolated amastigotes by the esters. Furthermore, relatively high concentrations of L-leucine, methanol, or benzyl alcohol were not demonstrably toxic to the amastigotes. We postulate that ester concentrations sufficient to damage the intracellular amastigotes may be obtained within the p.v. after exposure of infected macrophages to the esters. Esters preferentially hydrolyzed by parasite enzymes may be expected to be leishmanicidal, but less damaging to the host.

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confidence: 99%

Destruction of Leishmania mexicana amazonensis amastigotes within macrophages by lysosomotropic amino acid esters.

Rabinovitch¹,

Zilberfarb²,

Ramazeilles³

1986

The Journal of Experimental Medicine

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“…Barlow and Triemer (1986) observed acid phosphatase activity in the Golgi cisternae and ER of the heterotrophic dinoflagellate, C. cohnii. Acid phosphatase activity has also been detected in lysosome-like structures, the ER, and the Golgi complex of many non-dinoflagellate protists (Sommer and Blum, 1965;Elliott and Clemmons, 1966;Dembitzer, 1968;Stoltze et al, 1969;McAlpine, 1970;Brooker, 1971;Gomez et al, 1974;Langreth and Balber, 1975;Ryter and Bowers, 1976;Grab et al, 1997). Smaller ELF-97 deposits occurred throughout the cytoplasm in some P. shumwayae cells.…”

Section: Discussionmentioning

confidence: 94%

Phosphatase activity in the heterotrophic dinoflagellate Pfiesteria shumwayae

2006

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“…Elle concentre, tout au moins chez L. donovani, une importante activité phosphatasique acide [McAlpine, 1970].…”

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Leishmaniose cutanée: éude ultrastructurale

Bourlond-Reinert

Nicolay

1975

Dermatology

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While in general agreement with previous searchers, the authors direct their attention at peculiar or unknown structures such as: a huge phagosome sometimes loaded with a paracristalline rod; an occasional set of parallel microtubules along the reservoir; eventual duplication of the blepharoplast and even of the flagellum. There appear to be some 90 microtubules in the hyaloplasm of Leishmania tropica.

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Electronic cytochemical demonstration of a lysosome in Leishmania donovani

Cited by 11 publications

References 7 publications

Destruction of Leishmania mexicana amazonensis amastigotes within macrophages by lysosomotropic amino acid esters.

Destruction of Leishmania mexicana amazonensis amastigotes within macrophages by lysosomotropic amino acid esters.

Phosphatase activity in the heterotrophic dinoflagellate Pfiesteria shumwayae

Leishmaniose cutanée: éude ultrastructurale

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