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Nuclear and cytoplasmic lectin binding sites in promastigotes of Leishmania

M A Vannier-Santos1, E M Saraiva, W de Souza

  • 1Laboratório de Ultraestrutura Celular e Microscopia Eletrônica, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brasil.

The Journal of Histochemistry and Cytochemistry : Official Journal of the Histochemistry Society
|June 1, 1991
PubMed

Insights

Intracellular lectin binding sites were found in Leishmania mexicana amazonensis promastigotes, particularly in the nucleus and endoplasmic reticulum. This suggests the presence of endogenous carbohydrate-binding molecules involved in cellular functions.

Area of Science:

  • Cell Biology
  • Parasitology
  • Biochemistry

Background:

  • Leishmania parasites possess complex glycoconjugates.
  • Intracellular localization and function of these molecules remain largely uncharacterized.

Purpose of the Study:

  • To investigate the presence and localization of intracellular lectin binding sites in Leishmania mexicana amazonensis promastigotes.
  • To identify potential endogenous carbohydrate-binding molecules within the parasite.

Main Methods:

  • Utilized direct and indirect lectin-gold techniques on Lowicryl K4M-embedded cells.
  • Employed various lectins specific for different carbohydrate residues.
  • Performed control experiments using fetuin-gold complex.

Main Results:

  • Most lectins labeled the nuclear compartment, with specific lectins (WFH, LFA) targeting nucleoli.
  • Endoplasmic reticulum showed frequent labeling, while the Golgi complex was not labeled.
  • Kinetoplast extremities were labeled, suggesting association with ribonucleoproteins.
  • Evidence for a sialic acid-binding molecule in Leishmania nuclei was observed.

Conclusions:

  • Leishmania mexicana amazonensis promastigotes contain intracellular lectin binding sites, primarily in the nucleus and endoplasmic reticulum.
  • These findings suggest the presence of nuclear and ER-associated glycoconjugates with potential roles in parasite biology.
  • Further research is warranted to elucidate the precise function of these intracellular glycoconjugates.

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