Climate change agitates interactions between organisms and the environment and forces them to adapt, migrate, get replaced by others, or extinct. Marine environments are extremely sensitive to ...climate change that influences their ecological functions and microbial community including fungi. Fungi from marine habitats are engaged and adapted to perform diverse ecological functions in marine environments. Several studies focus on how complex interactions with the surrounding environment affect fungal evolution and their adaptation. However, a review addressing the adaptation of marine fungi to climate change is still lacking. Here we have discussed the adaptations of fungi in the marine environment with an example of
Hortaea werneckii
and
Aspergillus terreus
which may help to reduce the risk of climate change impacts on marine environments and organisms. We address the ecology and evolution of marine fungi and the effects of climate change on them to explain the adaptation mechanism. A review of marine fungal adaptations will show widespread effects on evolutionary biology and the mechanism responsible for it.
Molecular studies of salt tolerance of eukaryotic microorganisms have until recently been limited to the baker's yeast Saccharomyces cerevisiae and a few other moderately halotolerant yeast. ...Discovery of the extremely halotolerant and adaptable fungus Hortaea werneckii and the obligate halophile Wallemia ichthyophaga introduced two new model organisms into studies on the mechanisms of salt tolerance in eukaryotes. H. werneckii is unique in its adaptability to fluctuations in salt concentrations, as it can grow without NaCl as well as in the presence of up to 5 M NaCl. On the other hand, W. ichthyophaga requires at least 1.5 M NaCl for growth, but also grows in up to 5 M NaCl. Our studies have revealed the novel and intricate molecular mechanisms used by these fungi to combat high salt concentrations, which differ in many aspects between the extremely halotolerant H. werneckii and the halophilic W. ichthyophaga. Specifically, the high osmolarity glycerol signaling pathway that is important for sensing and responding to increased salt concentrations is here compared between H. werneckii and W. ichthyophaga. In both of these fungi, the key signaling components are conserved, but there are structural and regulation differences between these pathways in H. werneckii and W. ichthyophaga. We also address differences that have been revealed from analysis of their newly sequenced genomes. The most striking characteristics associated with H. werneckii are the large genetic redundancy, the expansion of genes encoding metal cation transporters, and a relatively recent whole genome duplication. In contrast, the genome of W. ichthyophaga is very compact, as only 4884 protein-coding genes are predicted, which cover almost three quarters of the sequence. Importantly, there has been a significant increase in their hydrophobins, cell-wall proteins that have multiple cellular functions.
We report the first case of peritoneal dialysis (PD) patients with peritonitis from Hortaea werneckii, a halotolerant black yeast-like fungus. The pathogen was confirmed by nucleotide sequences of ...internal transcribed spacer regions of the ribosomal RNA gene. A potential cause of this infection was tinea nigra on the patient’s palm. Therefore, gloving might be advised during PD bag exchange in patients or caregivers who have an obvious lesion of the palm.
Fungi have been found in every marine habitat that has been explored; however, the diversity and functions of fungi in the ocean are poorly understood. In this study, fungi were cultured from the ...marine environment in the vicinity of Woods Hole, MA, USA, including from plankton, sponge, and coral. Our sampling resulted in 35 unique species across 20 genera. We observed many isolates by time-lapse, differential interference contrast (DIC) microscopy and analyzed modes of growth and division. Several black yeasts displayed highly unconventional cell division cycles compared to those of traditional model yeast systems. Black yeasts have been found in habitats inhospitable to other life and are known for halotolerance, virulence, and stress resistance. We find that this group of yeasts also shows remarkable plasticity in terms of cell size control, modes of cell division, and cell polarity. Unexpected behaviors include division through a combination of fission and budding, production of multiple simultaneous buds, and cell division by sequential orthogonal septations. These marine-derived yeasts reveal alternative mechanisms for cell division cycles that seem likely to expand the repertoire of rules established from classic model system yeasts.
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•35 fungal species were isolated from the ocean, sponge, coral, and coastal sediment•Time-lapse imaging reveals unusual cell cycles, cell-division patterns, and polarity
Mitchison-Field et al. isolate, culture, and perform time-lapse DIC microscopy of marine-derived fungi from Woods Hole, MA. They identify a group of black yeast with unconventional cell division cycles and modes of cell division.
Hortaea werneckii causes Tinea nigra, a rare superficial mycosis. It has not been reported in Iran yet. We report a case of an Iranian boy resident of Amol (Mazandaran, Iran) that developed brown ...macules on his left palm. Direct microscopic examination and culture confirmed the diagnosis of Tinea nigra.
Resumen La tinea nigra es una infrecuente micosis superficial causada por el hongo dematiáceo Hortaea werneckii. Se presenta habitualmente en zonas costeras tropicales, siendo muy escasos los ...reportes en países sudamericanos con climas más templados. Habitualmente corresponde a infecciones importadas por viajeros. Se presenta el caso de una paciente adulta chilena, sin historia previa de viajes recientes, cursando con cuadro clínico y microbiológico compatible con tinea nigra palmar, tratado con itraconazol oral y sertaconazol tópico con respuesta favorable. Esta paciente corresponde al primer caso reportado en Chile de origen autóctono.
Hortaea werneckii M-3, a black yeast isolated from the marine sediment of the West Pacific, can utilize polyester polyurethane (PU, Impranil DLN) as a sole carbon source. Here, we present the ...complete genome of Hortaea werneckii M-3 with the focus on PU degradation enzymes. The total genome size is 38,167,921 bp, consisting of 186 contigs with a N50 length of 651,266 bp and a GC content of 53.06%. Genome annotation analysis predicts a total of 13,462 coding genes, which include 99 tRNAs and 105 rRNAs. Some genes encoding PU degrading enzymes including cutinase and urease are identified in this genome. The genome analysis of Hortaea werneckii M-3 will be helpful for further understanding the degradation mechanism of polyester PU by marine yeasts.
The in vitro susceptibility of molecularly identified Hortaea werneckii isolates (n = 37), the causative agent of tinea nigra, originating from clinical and environmental sources was determined for ...nine antifungal agents. Posaconazole had the lowest geometric mean minimum inhibitory concentration (GM MIC) (0.07 µg/mL), followed by voriconazole (0.13 µg/mL), isavuconazole (0.14 µg/mL), itraconazole (0.16 µg/mL), terbinafine (0.19 µg/mL) and amphotericin B (0.92 µg/mL). In contrast, fluconazole (14.56 µg/mL), caspofungin (2.41 µg/mL) and anidulafungin (1.42 µg/mL) demonstrated the highest GM MICs/MECs against H. werneckii.
Melanins are one of the magnificent natural pigments synthesized by a wide range of microorganisms including different species of fungi and bacteria. Marine black yeasts appear to be potential ...prospects for the synthesis of natural melanin pigment. As a result, the goal of this research was to isolate a marine black yeast melanin-producing strain and improve the culturing conditions in order to maximize the yield of such a valuable pigment.
Among five locally isolated black yeast strains, the only one that demonstrated a potent remarkable melanin pigment production was identified using ITS rDNA as Hortaea werneckii AS1. The extracted pigment's physiochemical characterization and analytical investigation with Ultraviolet-Visible (UV) spectrophotometry, Fourier Transform-Infrared spectroscopy (FTIR), and Scanning Electron Microscope (SEM) confirmed its nature as a melanin pigment. The data obtained from the polynomial model's maximum point suggested that CaCl
, 1.125 g/L; trace element, 0.25 ml/L; and a culture volume 225 mL/500 mL at their optimal values were the critical three elements impacting melanin production. In comparison with the baseline settings, the response surface methodology (RSM) optimization approach resulted in a 2.0 - fold improvement in melanin output.
A maximum melanin yield of 0.938 g/L proved the halotolerant H. werneckii AS1 potentiality as a source for natural melanin pigment synthesis 'when compared to some relevant black yeast strains' and hence, facilitating its incorporation in a variety of pharmaceutical and environmental applications.
Abstract
Background
The great diversity of lifestyles and survival strategies observed in fungi is reflected in the many ways in which they reproduce and recombine. Although a complete absence of ...recombination is rare, it has been reported for some species, among them 2 extremotolerant black yeasts from Dothideomycetes: Hortaea werneckii and Aureobasidium melanogenum. Therefore, the presence of diploid strains in these species cannot be explained as the product of conventional sexual reproduction.
Results
Genome sequencing revealed that the ratio of diploid to haploid strains in both H. werneckii and A. melanogenum is about 2:1. Linkage disequilibrium between pairs of polymorphic loci and a high degree of concordance between the phylogenies of different genomic regions confirmed that both species are clonal. Heterozygosity of diploid strains is high, with several hybridizing genome pairs reaching the intergenomic distances typically seen between different fungal species. The origin of diploid strains collected worldwide can be traced to a handful of hybridization events that produced diploids, which were stable over long periods of time and distributed over large geographic areas.
Conclusions
Our results, based on the genomes of over 100 strains of 2 black yeasts, show that although they are clonal, they occasionally form stable and highly heterozygous diploid intraspecific hybrids. The mechanism of these apparently rare hybridization events, which are not followed by meiosis or haploidization, remains unknown. Both extremotolerant yeasts, H. werneckii and even more so A. melanogenum, a close relative of the intensely recombining and biotechnologically relevant Aureobasidium pullulans, provide an attractive model for studying the role of clonality and ploidy in extremotolerant fungi.