Hortaea werneckii is a melanized meristematic ascomycetous fungus of the genus Capnodiales. It is known primarily as the etiological agent of the human mycotic infection tinea nigra and as an important eukaryotic model organisms for the study of halotolerance. This black yeast is characterized by its ability to survive in the entire range of NaCl concentrations, from 0 to 30 % NaCl, as well as in the presence of some other chaotropic salts. It’s primary ecological niche are salt pans, other saline waters and bitterns, waters rich with Mg salts.
In this diploma thesis we analysed the growth of several strains of H. werneckii of differentiated ploidies (n and 2n) grown in media without NaCl and with 17 % NaCl. We observed the morphology and measured the size of cultured cells under a light microscope. The obtained results were analysed with various statistical methods, including descriptive statistics, PCA, t test and Wilcox test.
By comparing the growth of different strains of H. werneckii in media of different salinity, we determined that in the medium without added salt, there were more yeast cells present, whereas in the medium with 17%NaCl we noticed more hyphae and pseudohyphae. Additionally, we observed wider conidia in the hypersaline medium compared to the medium without salt. Haploid strains more frequently formed unicellular conidia than diploid strains. The latter grew shorter and narrower one- and two-celled conidia compared to the haploid strains. They also exhibited a greater tendency to grow in the form of hyphae and pseudohyphae, indicating a higher adaptation of diploid strains to the extremely salty environment.
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