Induction by
            <i>Klebsiella aerogenes</i>
            of a Melanin-Like Pigment in
            <i>Cryptococcus neoformans</i>

Frasés, Susana; Chaskes, Stuart; Dadachova, Ekaterina; Casadevall, Arturo

doi:10.1128/aem.72.2.1542-1550.2006

Cited by 64 publications

(52 citation statements)

References 23 publications

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“…These include several catecholamines, such as methyl-DOPA and norepinephrine (Garcia-Rivera et al, 2005). In addition, C. neoformans can use substrates produced by bacteria for melanization (Frases et al, 2006(Frases et al, , 2007.…”

Section: Discussionmentioning

confidence: 99%

“…C. neoformans presumably melanizes during mammalian infection by scavenging substrates from tissue that remain unidentified (Rosas et al, 2000a). Recent reports have enumerated an expanded list of substrates that can be used for melanization in vitro, and these include several bacterial products (Frases et al, 2006(Frases et al, , 2007Garcia-Rivera et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Cryptococcus neoformans laccase catalyses melanin synthesis from both d- and l-DOPA

et al. 2007

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The human fungal pathogen Cryptococcus neoformans produces melanin in the presence of various substrates, including the L enantiomer of 3,4-dihydroxyphenylalanine (DOPA). The enzyme laccase catalyses the formation of melanin by oxidizing L-DOPA, initiating a series of presumably spontaneous reactions that ultimately leads to the polymerization of the pigment in the yeast cell wall. There, melanin protects the cell from a multitude of environmental and host assaults. Thus, the ability of C. neoformans to produce pigments from a variety of available substrates is likely to confer a survival advantage. A number of C. neoformans isolates of different serotypes produced pigments from D-DOPA, the stereoisomer of L-DOPA. Acid-resistant particles were isolated from pigmented C. neoformans cells grown in the presence of D-DOPA. Biophysical characterization showed the particles had a stably detectable free-radical signal by EPR, and negative zeta potential, similar to L-DOPA-derived particles. No major differences were found between L-and D-DOPA ghosts in terms of binding to anti-melanin antibodies, or in overall architecture when imaged by electron microscopy. C. neoformans cells utilized L-and D-DOPA at a similar rate. Overall, our results indicate that C. neoformans shows little stereoselectivity for utilizing DOPA in melanin synthesis. The ability of C. neoformans to use both L and D enantiomers for melanization implies that this organism has access to a greater potential pool of substrates for melanin synthesis, and this could potentially be exploited in the design of therapeutic inhibitors of laccase.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cryptococcus neoformans laccase catalyses melanin synthesis from both d- and l-DOPA

et al. 2007

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“…For example, in cheese ripening, the interaction between Kluyveromyces lactis and Brevibacterium linens results in an altered profile of aromatic volatile sulfur compounds, which is believed to be due to the supply of an important precursor molecule, methanethiol, by the bacterium to the yeast (10). Another example of such anabolism is the synthesis of melanin pigments during the Klebsiella aerogenesCryptococcus neoformans BFI (114,115). C. neoformans is able to use homogentisic acid produced by K. aerogenes as a precursor for the synthesis of melanin pigments that enhance the virulence of the fungus and afford it protection against UV and other environmental stresses (114,115).…”

Section: Bacterial-fungal Molecular Interactions and Communicationmentioning

confidence: 99%

“…Another example of such anabolism is the synthesis of melanin pigments during the Klebsiella aerogenesCryptococcus neoformans BFI (114,115). C. neoformans is able to use homogentisic acid produced by K. aerogenes as a precursor for the synthesis of melanin pigments that enhance the virulence of the fungus and afford it protection against UV and other environmental stresses (114,115). A less beneficial conversion of a bacterial metabolite occurs upon coculturing of P. aeruginosa and C. albicans, since a pyocyanin precursor produced by the former is converted to a toxic red pigment within the fungus (131,257).…”

Section: Bacterial-fungal Molecular Interactions and Communicationmentioning

confidence: 99%

Bacterial-Fungal Interactions: Hyphens between Agricultural, Clinical, Environmental, and Food Microbiologists

Frey‐Klett

Burlinson

Deveau

et al. 2011

Microbiol Mol Biol Rev

737

531

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SUMMARY Bacteria and fungi can form a range of physical associations that depend on various modes of molecular communication for their development and functioning. These bacterial-fungal interactions often result in changes to the pathogenicity or the nutritional influence of one or both partners toward plants or animals (including humans). They can also result in unique contributions to biogeochemical cycles and biotechnological processes. Thus, the interactions between bacteria and fungi are of central importance to numerous biological questions in agriculture, forestry, environmental science, food production, and medicine. Here we present a structured review of bacterial-fungal interactions, illustrated by examples sourced from many diverse scientific fields. We consider the general and specific properties of these interactions, providing a global perspective across this emerging multidisciplinary research area. We show that in many cases, parallels can be drawn between different scenarios in which bacterial-fungal interactions are important. Finally, we discuss how new avenues of investigation may enhance our ability to combat, manipulate, or exploit bacterial-fungal complexes for the economic and practical benefit of humanity as well as reshape our current understanding of bacterial and fungal ecology.

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“…However, practically nothing is known about the sources of melanin precursors in the environment. Recently, we showed that interaction between a bacterium, Klebsiella aerogenes, and C. neoformans resulted in fungal melanization (5). The mechanism for that process involved the production of dopamine by the bacteria that was used as a melanin precursor by C. neoformans.…”

mentioning

confidence: 99%

Cryptococcus neoformans Can Utilize the Bacterial Melanin Precursor Homogentisic Acid for Fungal Melanogenesis

Frasés¹,

Salazar²,

Dadachova

et al. 2007

Appl Environ Microbiol

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Cryptococcus neoformans melanizes in the environment and in mammalian tissues, but the process of melanization in either venue is mysterious given that this microbe produces melanin only from exogenous substrates. Understanding the process of melanization is important because melanization is believed to protect against various stresses in the environment, including UV radiation, and pigment production is associated with virulence. Melanization in C. neoformans requires the availability of diphenolic precursors. In contrast, many bacteria synthesize melanin from homogentisic acid (HGA). We report that C. neoformans strains representing all four serotypes can produce a brown pigment from HGA. The brown pigment was acid resistant and had the electron paramagnetic resonance spectrum of a stable free radical, qualities that identified it as a melanin. Melanin "ghost"-like particles obtained from pigmented C. neoformans cells were hydrophobic, fluorescent under a variety of irradiation wavelengths, negatively charged, insoluble in organic solvents and alcohols, resistant to degradation by strong acids, and vulnerable to bleaching. HGA melanization was laccase dependent and repressed by high concentrations of glucose. The ability of C. neoformans to utilize a bacterial melanin precursor compound suggests a new substrate source for melanization in the environment.

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Induction by Klebsiella aerogenes of a Melanin-Like Pigment in Cryptococcus neoformans

Cited by 64 publications

References 23 publications

Cryptococcus neoformans laccase catalyses melanin synthesis from both d- and l-DOPA

Cryptococcus neoformans laccase catalyses melanin synthesis from both d- and l-DOPA

Bacterial-Fungal Interactions: Hyphens between Agricultural, Clinical, Environmental, and Food Microbiologists

Cryptococcus neoformans Can Utilize the Bacterial Melanin Precursor Homogentisic Acid for Fungal Melanogenesis

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