Effects of microplusin, a copper-chelating antimicrobial peptide, against Cryptococcus neoformans

Fernanda D. Silva, Diego C.P. Rossi, Luis R. Martinez, Susana Frases, Fernanda L. Fonseca, Claudia Barbosa L. Campos, Marcio L. Rodrigues, Joshua D. Nosanchuk, Sirlei Daffre

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Microplusin is an antimicrobial peptide isolated from the cattle tick Rhipicephalus (Boophilus) microplus. Its copper-chelating ability is putatively responsible for its bacteriostatic activity against Micrococcus luteus as microplusin inhibits respiration in this species, which is a copper-dependent process. Microplusin is also active against Cryptococcus neoformans (MIC 50 = 0.09 μM), the etiologic agent of cryptococcosis. Here, we show that microplusin is fungistatic to C. neoformans and this inhibitory effect is abrogated by copper supplementation. Notably, microplusin drastically altered the respiratory profile of C. neoformans. In addition, microplusin affects important virulence factors of this fungus. We observed that microplusin completely inhibited fungal melanization, and this effect correlates with the inhibition of the related enzyme laccase. Also, microplusin significantly inhibited the capsule size of C. neoformans. Our studies reveal, for the first time, a copper-chelating antimicrobial peptide that inhibits respiration and growth of C. neoformans and modifies two major virulence factors: melanization and formation of a polysaccharide capsule. These features suggest that microplusin, or other copper-chelation approaches, may be a promising therapeutic for cryptococcosis.

Original languageEnglish (US)
Pages (from-to)64-72
Number of pages9
JournalFEMS Microbiology Letters
Issue number1
StatePublished - Nov 2011


  • Antimicrobial peptide
  • Cryptococcus neoformans
  • Microplusin

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics


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