Related Experiment Video

Updated: Aug 7, 2026

Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
12:37

Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model

Published on: September 7, 2013

Melanin as a potential cryptococcal defence against microbicidal proteins

T L Doering1, J D Nosanchuk, W K Roberts

  • 1The Department of Pharmacology, Cornell University Medical College, New York, NY 10021, USA. tdoering@mail.med.cornell.edu

Medical Mycology
|July 28, 1999
PubMed

Insights

Cryptococcus neoformans melanin binds proteins and protects the fungus from microbicidal peptides. This suggests melanin plays a role in fungal virulence by neutralizing host defenses.

Area of Science:

  • Medical Mycology
  • Biochemistry

Background:

  • Cryptococcus neoformans is a significant fungal pathogen.
  • Melanin production in C. neoformans is linked to virulence, but its precise role is unknown.

Purpose of the Study:

  • To investigate the protein-binding capacity of C. neoformans melanin.
  • To determine if melanin protects against microbicidal peptides.

Main Methods:

  • Studied melanin-protein interactions under varying pH and concentrations.
  • Assessed the susceptibility of melanized C. neoformans cells to defensins, protegrins, and magainins.
  • Investigated the effect of melanin on the fungicidal activity of microbicidal peptides.

Main Results:

  • C. neoformans melanin binds diverse fungal and mammalian proteins in a pH- and concentration-dependent manner.
  • Melanized cells exhibited reduced susceptibility to killing by three distinct microbicidal peptides.
  • Pre-incubation of peptides with melanin particles diminished their fungicidal activity.

Conclusions:

  • C. neoformans melanin sequesters microbicidal peptides, abrogating their activity.
  • Melanin's ability to bind proteins and neutralize antimicrobial peptides suggests a protective role in fungal pathogenesis.

More Related Videos

Methods to Inhibit Bacterial Pyomelanin Production and Determine the Corresponding Increase in Sensitivity to Oxidative Stress11:00

Methods to Inhibit Bacterial Pyomelanin Production and Determine the Corresponding Increase in Sensitivity to Oxidative Stress

Published on: August 31, 2015

Assessing the Putative Anticryptococcal Properties of Crude and Clarified Extracts from Mollusks09:18

Assessing the Putative Anticryptococcal Properties of Crude and Clarified Extracts from Mollusks

Published on: December 2, 2022

Related Concept Videos

Cell-mediated Immune Responses01:40

Cell-mediated Immune Responses

Overview
Pigmentation01:19

Pigmentation

The color of the skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred to the keratinocytes via melanosomes.
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Antimicrobial Proteins01:23

Antimicrobial Proteins

Antimicrobial proteins are important components of the immune system. They aid the body in combating pathogens by either killing them directly or hindering their replication processes. Four main types of antimicrobial substances are interferons, the complement system, iron-binding proteins, and antimicrobial proteins.
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
Cryptococcal Meningitis01:27

Cryptococcal Meningitis

Cryptococcal meningitis is a life-threatening opportunistic infection predominantly associated with HIV/AIDS, accounting for over 100,000 deaths annually worldwide. However, it also affects individuals with other forms of immunosuppression, including those undergoing immunosuppressive therapy, organ transplant recipients, patients with innate immunodeficiencies, and individuals with hematological disorders. The infection is caused mainly by Cryptococcus neoformans and Cryptococcus gattii,...
Antifungal Agents01:15

Antifungal Agents

Amphotericin B is a broad-spectrum antifungal agent that exploits structural differences between fungal and mammalian cell membranes. Its amphipathic structure—featuring a hydrophobic polyene-lactone ring and a hydrophilic region containing mycosamine and carboxylic acid groups—enables selective binding to ergosterol, a sterol predominantly found in fungal plasma membranes. This selective interaction underlies the drug’s antifungal activity, although weak binding to cholesterol contributes to...
Antiprotozoal Agents01:21

Antiprotozoal Agents

Leishmaniasis is a widespread parasitic disease caused by several Leishmania species. It affects millions of people each year and remains a major public health problem in endemic regions. First-line treatment relies on pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate. Even so, how these drugs work has not been fully clear, especially their interaction with parasite-specific biochemical pathways. One key target is trypanothione reductase (TR), an enzyme that...