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Putative structure and characteristics of a red water-soluble pigment secreted by Penicillium marneffei

Sonia Bhardwaj1, Anshuman Shukla, Sourav Mukherjee

  • 1Postgraduate Institute of Medical Education and Research, Chandigarh, India.

Medical Mycology
|July 27, 2007
PubMed

Insights

Penicillium marneffei secretes a brick red pigment that acts as a pH indicator. Structural analysis revealed unique chemical bonds and moieties, aiding in understanding this pathogenic fungus.

Area of Science:

  • Mycology
  • Biochemistry
  • Chemical Biology

Background:

  • Penicillium marneffei is a dimorphic fungus.
  • This fungus produces a characteristic brick-red pigment during growth below 30°C.
  • The pigment diffuses into standard microbiological media.

Purpose of the Study:

  • To purify and determine the structure of the pigment produced by Penicillium marneffei.
  • To investigate the pigment's properties, including its pH buffering and indicator capabilities.
  • To compare the pigment's structure with related fungal pigments.

Main Methods:

  • Pigment purification using reverse-phase liquid chromatography.
  • Structural determination via elemental and spectral analyses: Atomic Absorption Spectroscopy (AAS), UV-Visible (UV-VIS), fluorescence, Infrared (IR), Nuclear Magnetic Resonance (NMR), and tandem Mass Spectrometry (MS-MS).

Main Results:

  • The pigment exhibits buffering capacity, maintaining an alkaline pH of 8.0.
  • It functions as a colorimetric pH indicator across a broad pH range, with degradation at pH ~2.0.
  • Structural analysis revealed a phenalene carbon framework, disulfide bond dimerization, and a tetramethyl-dihydropyrrole moiety, distinguishing it from herquinone.

Conclusions:

  • The elucidated structure of the Penicillium marneffei pigment provides insights into its chemical characteristics.
  • The pigment's properties suggest potential roles in the fungus's biology.
  • Understanding the pigment's structure aids in comprehending the pathogenicity of Penicillium marneffei.

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