Occurrence of <i>Exophiala werneckii</i> on salted freshwater fish <i>Osteoglossum bicirrhosum</i>

Mok, Wai Yin; Castelo, Francisco Pereira; Silva, M. S. Barreto Da

doi:10.1111/j.1365-2621.1981.tb01843.x

Cited by 29 publications

(11 citation statements)

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“…It was primarily known as a causative agent of tinea nigra , a superficial mycotic infection of the human skin mainly affecting the palms [9]. It was also found on salty food [10] and other low-water-activity substrates such as arid inorganic and organic surfaces [11], seawater [12] and beach soil [13]. The primary environmental ecological habitat of H. werneckii is probably hypersaline water in evaporite ponds of solar eutrophic salterns [14], [15] but in the salterns it was also found on wood immersed in brine [16], in biofilms on the surface of hypersaline waters, in the soil in dry evaporite ponds and in the saltern microbial mats [14].…”

Section: Introductionmentioning

confidence: 99%

Whole Genome Duplication and Enrichment of Metal Cation Transporters Revealed by De Novo Genome Sequencing of Extremely Halotolerant Black Yeast Hortaea werneckii

et al. 2013

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Hortaea werneckii, ascomycetous yeast from the order Capnodiales, shows an exceptional adaptability to osmotically stressful conditions. To investigate this unusual phenotype we obtained a draft genomic sequence of a H. werneckii strain isolated from hypersaline water of solar saltern. Two of its most striking characteristics that may be associated with a halotolerant lifestyle are the large genetic redundancy and the expansion of genes encoding metal cation transporters. Although no sexual state of H. werneckii has yet been described, a mating locus with characteristics of heterothallic fungi was found. The total assembly size of the genome is 51.6 Mb, larger than most phylogenetically related fungi, coding for almost twice the usual number of predicted genes (23333). The genome appears to have experienced a relatively recent whole genome duplication, and contains two highly identical gene copies of almost every protein. This is consistent with some previous studies that reported increases in genomic DNA content triggered by exposure to salt stress. In hypersaline conditions transmembrane ion transport is of utmost importance. The analysis of predicted metal cation transporters showed that most types of transporters experienced several gene duplications at various points during their evolution. Consequently they are present in much higher numbers than expected. The resulting diversity of transporters presents interesting biotechnological opportunities for improvement of halotolerance of salt-sensitive species. The involvement of plasma P-type H+ ATPases in adaptation to different concentrations of salt was indicated by their salt dependent transcription. This was not the case with vacuolar H+ ATPases, which were transcribed constitutively. The availability of this genomic sequence is expected to promote the research of H. werneckii. Studying its extreme halotolerance will not only contribute to our understanding of life in hypersaline environments, but should also identify targets for improving the salt- and osmotolerance of economically important plants and microorganisms.

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Section: Introductionmentioning

confidence: 99%

Whole Genome Duplication and Enrichment of Metal Cation Transporters Revealed by De Novo Genome Sequencing of Extremely Halotolerant Black Yeast Hortaea werneckii

et al. 2013

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“…Since H. werneckii does not show any keratin-degrading activity, it does not invade the living tissue below and so the infection is only a cosmetic problem (Gö ttlich et al 1995). Besides its involvement in tinea nigra, H. werneckii was also known as one of the few species of fungi capable of contaminating food preserved with high concentrations of NaCl (Mok and Barreto da Silva 1981), without showing any obligate requirement for NaCl (Andrews and Pitt 1987). In addition to human skin and salty food, the fungus has been isolated from seawater (Iwatsu and Udagawa 1988), marine fish (Todaro et al 1983), beach soil (de Hoog and Gué ho 1998) and arid inorganic and organic surfaces (Krumbein et al 1996).…”

Section: Ecology Of Hortaea Werneckiimentioning

confidence: 99%

Ecology and molecular adaptations of the halophilic black yeast Hortaea werneckii

Gunde‐Cimerman

Plemenitaš

2006

Rev Environ Sci Biotechnol

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Molecular studies on halophilic adaptations have focused on prokaryotic microorganisms due to a lack of known appropriate eukaryotic halophilic microorganisms. However, the black yeast Hortaea werneckii has been identified as the dominant fungal species in hypersaline waters on three continents. It represents a new model organism for studying the mechanisms of salt tolerance in eukaryotes. Ultrastructural studies of the H. werneckii cell wall have shown that it synthesizes dihydroxynaphthalene (DHN) melanin under both saline and non-saline growth conditions. However, melanin granules in the cell walls are organized in a salt-dependent way, implying the potential osmoprotectant role of melanin. At the level of membrane structure, H. werneckii maintains a sterol-to-phospholipid ratio significantly lower than the salt-sensitive Saccharomyces cerevisiae. Accordingly, membranes of H. werneckii are more fluid over a wide range of NaCl concentrations, indicating high intrinsic salt stress tolerance. Even H. werneckii grown in high NaCl concentrations maintains very low intracellular amounts of potassium and sodium, demonstrating the sodium-excluder character of this organism. The salt-dependent expressions of two HwENA genes suggest roles for them in the adaptation to changing salt concentrations. The high similarity of these ENA ATPases to other fungal ENA ATPases involved in Na + /K + transport indicates their potential importance in H. werneckii ion homeostasis. Glycerol is the main compatible solute which accumulates in the cytoplasm of H. werneckii at high salinity, although it seems that mycosporines may also act as supplementary compatible solutes. Salt dependent increase in glycerol synthesis is supported by the identification of two copies of a gene putatively coding for glycerol-3-phosphate-dehydrogenase. Expression of only one of these genes is salt dependent.

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“…On the basis of ecophysiological studies it was suggested that salt might be the decisive factor in the etiology of tinea nigra and H. werneckii ecology. In addition to human skin, the fungus has been isolated from seawater (Iwatsu and Udagawa, 1988), marine fish (Todaro et al, 1983), salted freshwater fish (Mok et al, 1981) and beach soil (de Hoog and Gueho, 1998). Nevertheless, its primary environmental ecological niche remained was not known.…”

Section: Hortaea Werneckii a Halophilic "Black Yeast"mentioning

confidence: 99%

Adaptation to Life at High Salt Concentrations in Archaea, Bacteria, and Eukarya

Gunde‐Cimerman¹,

Oren²,

Plemenitaš³

2005

Cellular Origin, Life in Extreme Habitats and Astrobiology

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Occurrence of Exophiala werneckii on salted freshwater fish Osteoglossum bicirrhosum

Cited by 29 publications

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Whole Genome Duplication and Enrichment of Metal Cation Transporters Revealed by De Novo Genome Sequencing of Extremely Halotolerant Black Yeast Hortaea werneckii

Whole Genome Duplication and Enrichment of Metal Cation Transporters Revealed by De Novo Genome Sequencing of Extremely Halotolerant Black Yeast Hortaea werneckii

Ecology and molecular adaptations of the halophilic black yeast Hortaea werneckii

Adaptation to Life at High Salt Concentrations in Archaea, Bacteria, and Eukarya

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