The Surface Membrane of Leishmania

Hernández, Ángel González; Argüello, Carlos; Ayesta, C.; Dagger, Fracehuli; Infante, Ramón Benito; Stojanovich, D.; Dawidowicz, Karl; Riggione, Flavia; Riva, Gabriele

doi:10.1016/b978-0-08-026381-6.50007-3

Cited by 25 publications

(4 citation statements)

References 36 publications

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“…Using immune sera from four patients with cutaneous leishmaniasis, the 65,000tool wt antigen is similarly recognized on both African and Brazilian isolates of L. donovanL In this regard, Hernandez et al (19) have reported a virtually identical surface iodination profile for promastigotes of Leishmania braziliensis, an agent of cutaneous leishmaniasis. Here a major glycoprotein of 65,300 tool wt is seen together with a band of 54,000 mol wt and a doublet of 23,000/25,000 mol wt.…”

Section: Discussionmentioning

confidence: 94%

Surface antigens of Leishmania donovani promastigotes.

Lepay¹,

Nogueira²,

Cohn³

1983

The Journal of Experimental Medicine

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Surface antigen profiles of Leishmania donovani promastigote isolates have been studied. Surface patterns of Brazilian and African isolates display remarkable similarities and are extremely simple, consisting of three major peptides of 65,000, 25,000, and 23,000 mol wt. Surface iodination and biosynthetic labeling coupled to immunoprecipitation techniques revealed that a single major determinant of 65,000 mol wt is recognized in all strains by sera from kala-azar patients from both Brazil and Africa. This major determinant is not brought down by sera from normal individuals and shows no significant cross-reactivity with sera from Chagas' disease, leprosy, or syphilis patients. Binding to concanavalin A suggests a glycoprotein nature for this antigen. Sera from patients with cutaneous leishmaniasis (L. braziliensis) also recognized the same 65,000-mol wt determinant, although to a lesser extent. The possibility that this major surface antigen is shared, with minor differences, not only by L. donovani strains but between Leishmania species in general is suggested.

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Section: Discussionmentioning

confidence: 94%

Surface antigens of Leishmania donovani promastigotes.

Lepay¹,

Nogueira²,

Cohn³

1983

The Journal of Experimental Medicine

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“…Finally, attachment and phagocytosis of Leishmania sp. organisms by mammalian macrophages, in both promastigote and amastigote forms, is known to occur in the absence of serum, and it is suspected that attachment of these organisms may occur via an exposed glycoconjugate on the parasite surface (2,15,19,(27)(28)(29). In the present study, we have surveyed such glycoconjugates on L. donovani by using lectins, documenting some surface characteristics that remain stable and some that evolve through the amastigoteto-promastigote stage conversion.…”

Section: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~4mentioning

confidence: 93%

Stage-specific variations in lectin binding to Leishmania donovani

Wilson¹,

Pearson²

1984

Infect Immun

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Visceral leishmaniasis is caused by the dimorphic protozoan Leishmania donovani, which exists as an aflagellar amastigote within mammalian mononuclear phagocytes and as a flagellated extracellular promastigote in its sandfly vector. We have identified four plant lectins that bind to the L. donovani surface, and through these we have documented stage-specific differences in exposed surface carbohydrates. Concanavalin A bound to both promastigotes and amastigotes; binding was inhibited by mannose or alpha-methyl-mannoside, implying a mannose-containing residue on the surface of both parasite stages. Ricinus communis agglutinin, which binds to galactose-containing residues, also bound to both stages and was inhibited by lactose, implying a galactose-containing glycoconjugate on the parasite surface. Two other lectins, wheat germ agglutinin (WGA) and peanut agglutinin (PNA), exhibited stage specificity in their binding characteristics. Amastigotes bound WGA but not PNA. During the process of conversion from the amastigote to the promastigote stage, the WGA-binding glycoconjugate was lost, and a PNA-binding residue was newly displayed. WGA binding was inhibited by N-acetyl-D-glucosamine and was not altered by neuraminidase treatment, suggesting the presence of an exposed N-acetyl-D-glucosamine moiety on the amastigote surface. The PNA binding site is known to accommodate the oligosaccharide beta-D-galactose-(1----3)-N-acetyl-D-galactosamine; in our system, PNA may have identified an internal rather than a terminal galactose on the promastigote surface. Localized binding of WGA and PNA to the surface of intermediate phases of the parasite suggested inhomogeneous and changing surface characteristics during conversion from amastigote to promastigote stages. This evolution of L. donovani surface glycoconjugates may be important in the adaptation of the organism to its divergent mammalian host and arthropod vector environments.

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“…Those investigators have concluded that the leakage across membranes induced by such compounds occurs via membrane defects which are modulated by the presence at the membrane surface of endogenous anionic components (4). It is therefore tempting to propose that the differential inhibitory effects exerted by Mg2+ ions between Leishmania promastigotes and amastigotelike forms originate from a reduced binding to negative surface components which are either absent or nonexposed upon transformation to the amastigotelike form (18,31).…”

Section: Discussionmentioning

confidence: 99%

Enhanced action of amphotericin B on Leishmania mexicana resulting from heat transformation

Ramos

Milhaud

Cohen

et al. 1990

Antimicrob Agents Chemother

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A comparative study of the effect of the polyene antibiotic amphotericin B (AmB) on the viability of Leishmania mexicana promastigotes before and after their transformation by heat into amastigotelike forms was carried out. The kinetics of cell death were followed by spectrofluorometry with the nucleic acid-binding compound ethidium bromide. It was found that the rapid killing effect that is exerted by AmB on Leishmania promastigotes was even faster after their transformation into amastigotelike forms. Binding studies of AmB to Leishmania membranes by circular dichroism indicated that heat transformation modified it from noncooperative to cooperative binding, decreasing the amount of antibiotic that bound to the membranes. Thus, the increased rate of ethidium bromide incorporation into transformed cells was not related either to the amount of AmB bound or to an increased amount of ergosterol in the membrane (the ergosterol/phospholipid ratio was four times smaller after heat shock). An increase in the Mg2e content of the external aqueous solution was able to prevent the AmB-induced incorporation of ethidium bromide into Leishmania promastigotes to a greater extent (Ki = 13.8 mM) than it was into heat-transformed cells (Ki = 64 mM), suggesting that there were significant changes at the Leishmania cell surface on heat transformiltion. The significance of these results for understanding the mechanism of action of AmB on sensitive organisms is discussed.

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The Surface Membrane of Leishmania

Cited by 25 publications

References 36 publications

Surface antigens of Leishmania donovani promastigotes.

Surface antigens of Leishmania donovani promastigotes.

Stage-specific variations in lectin binding to Leishmania donovani

Enhanced action of amphotericin B on Leishmania mexicana resulting from heat transformation

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