1. The genus Wallemia - from contamination of food to health threatJanja Zajc, Nina Gunde-Cimerman, 2018, review article Abstract: The fungal genus Wallemia of the order Wallemiales (Wallemiomycotina, Basidiomycota) comprises the most xerotolerant, xerophilic and also halophilic species worldwide. Wallemia spp. are found in various osmotically challenged environments, such as dry, salted, or highly sugared foods, dry feed, hypersaline waters of solar salterns, salt crystals, indoor and outdoor air, and agriculture aerosols. Recently, eight species were recognized for the genus Wallemia, among which four are commonly associated with foods: W. sebi, W. mellicola, W. muriae and W. ichthyophaga. To date, only strains of W. sebi, W. mellicola and W. muriae have been reported to be related to human health problems, as either allergological conditions (e.g., farmer’s lung disease) or rare subcutaneous/cutaneous infections. Therefore, this allergological and infective potential, together with the toxins that the majority of Wallemia spp. produce even under saline conditions, defines these fungi as filamentous food-borne pathogenic fungi.
Keywords: food, air, pathogen, xerophile, halophile, mycotoxin, farmerʼs lung disease, subcutaneous infection
Published in DiRROS: 06.08.2024; Views: 26; Downloads: 32
 Full text (279,26 KB)
This document has many files! More... |
2. Insertion of a specific fungal 3'-phosphoadenosine-5'-phosphatase motif into a plant homologue improves halotoleranceand drought tolerance of plantsMeti Buh Gašparič, Metka Lenassi, Cene Gostinčar, Ana Rotter, Ana Plemenitaš, Nina Gunde-Cimerman, Kristina Gruden, Jana Žel, 2013, original scientific article Abstract: Soil salinity and drought are among the most serious agricultural and environmental problems of today. Therefore, investigations of plant resistance to abiotic stress have received a lot of attention in recent years. In this study, we identified the complete coding sequence of a 3′-phosphoadenosine-5′-phosphatase protein, ApHal2, from the halotolerant yeast Aureobasidium pullulans. Expression of the ApHAL2 gene in a Saccharomyces cerevisiae hal2 mutant complemented the mutant auxotrophy for methionine, and rescued the growth of the hal2 mutant in media with high NaCl concentrations. A 21-amino-acids-long region of the ApHal2 enzyme was inserted into the Arabidopsis thaliana homologue of Hal2, the SAL1 phosphatase. The inserted sequence included the META motif, which has previously been implicated in increased sodium tolerance of the Hal2 homologue from a related fungal species. Transgenic Arabidopsis plants overexpressing this modified SAL1 (mSAL1) showed improved halotolerance and drought tolerance. In a medium with an elevated salt concentration, mSAL1-expressing plants were twice as likely to have roots in a higher length category in comparison with the wild-type Arabidopsis and with plants overexpressing the native SAL1, and had 5% to 10% larger leaf surface area under moderate and severe salt stress, respectively. Similarly, after moderate drought exposure, the mSAL1-expressing plants showed 14% increased dry weight after revitalisation, with no increase in dry weight of the wild-type plants. With severe drought, plants overexpressing native SAL1 had the worst rehydration success, consistent with the recently proposed role of SAL1 in severe drought. This was not observed for plants expressing mSAL1. Therefore, the presence of this fungal META motif sequence is beneficial under conditions of increased salinity and moderate drought, and shows no drawbacks for plant survival under severe drought. This demonstrates that adaptations of extremotolerant fungi should be considered as a valuable resource for improving stress-tolerance in plant breeding in the future.
Keywords: soil salinity and drought, plant resistance, abiotic stress
Published in DiRROS: 02.08.2024; Views: 136; Downloads: 121
Full text (7,12 MB)
This document has many files! More... |
3. Stress tolerance of three opportunistic black yeastsJanja Zajc, Cene Gostinčar, Metka Lenassi, Nina Gunde-Cimerman, 2018, original scientific article Abstract: Many species of black yeasts can survive extremely harsh conditions and can quickly adapt to novel environments. These traits were proposed to have a role in the ability of some fungal species tocolonise indoor habitats inhospitable for majority of microorganisms, and to cause (opportunistic)infections in humans. In order to better understand the stress tolerance of black yeasts and thereby their opportunism, we focused our research on the three model black yeasts: the polyextremotolerant Au-reobasidium melanogenum and Exophiala dermatitidis, and the extremely halotolerant Hortaeawerneckii. These black yeasts are shown to thrive at temperatures, salinities, pH values and, H2O2 concentrations that inhibit growth of mesophilic species. Most importantly, unlike their close relatives they can not only grow, but also synthesize siderophores (E. dermatitidis) or degradeproteins (A. melanogenum) at 37 °C - traits that are crucial for pathogenesis in humans. These results support the hypothesis that the ability to cope with various environmental stresses is linked to the opportunistic behaviour of fungi. Therefore, better understanding of the connections between the stress-tolerant biology of black fungi and their ability to cause disease is needed, in particular due to their changing interactions with humans and their emerging pathogenicity.
Keywords: melanised fungi, temperature, NaCl, pH tolerance, ROS, oligotrophism, proteolytic activity, capsule
Published in DiRROS: 01.08.2024; Views: 109; Downloads: 64
Full text (1,00 MB)
This document has many files! More... |
4. High-quality genome sequence of the radioresistant bacterium Deinococcus ficus KS 0460Vera Y. Matrosova, Elena K. Gaidamakova, Kira S. Makarova, Olga Grichenko, Polina Klimenkova, Robert P. Volpe, Rok Tkavc, Gözen Ertem, Isabel H. Conze, Evelyne Brambilla, Nina Gunde-Cimerman, Tine Grebenc, Cene Gostinčar, 2017, original scientific article Abstract: The genetic platforms of Deinococcus species remain the only systems in which massive ionizing radiation (IR)-induced genome damage can be investigated in vivo at exposures commensurate with cellular survival. We report the whole genome sequence of the extremely IR-resistant rod-shaped bacterium Deinococcus ficus KS 0460 and its phenotypic characterization. Deinococcus ficus KS 0460 has been studied since 1987, first under the name Deinobacter grandis, then Deinococcus grandis. The D. ficus KS 0460 genome consists of a 4.019 Mbp sequence (69.7% GC content and 3894 predicted genes) divided into six genome partitions, five of which are confirmed to be circular. Circularity was determined manually by mate pair linkage. Approximately 76% of the predicted proteins contained identifiable Pfam domains and 72% were assigned to COGs. Of all D. ficus KS 0460 proteins, 79% and 70% had homologues in Deinococcus radiodurans ATCC BAA-816 and Deinococcus geothermalis DSM 11300, respectively. The most striking differences between D. ficus KS 0460 and D. radiodurans BAA-816 identified by the comparison of the KEGG pathways were as follows: (i) D. ficus lacks nine enzymes of purine degradation present in D. radiodurans, and (ii) D. ficus contains eight enzymes involved in nitrogen metabolism, including nitrate and nitrite reductases, that D. radiodurans lacks. Moreover, genes previously considered to be important to IR resistance are missing in D. ficus KS 0460, namely, for the Mn-transporter nramp, and proteins DdrF, DdrJ and DdrK, all of which are also missing in Deinococcus deserti. Otherwise, D. ficus KS 0460 exemplifies the Deinococcus lineage.
Keywords: Deinococcus-Thermus, Deinococcaceae, Deinococcus ficus, radiation-resistant, rod-shaped, phenotype characterization, genome analysis, phylogenetic analysis
Published in DiRROS: 25.07.2024; Views: 118; Downloads: 97
Full text (1,22 MB)
This document has many files! More... |
5. Fungi between extremotolerance and opportunistic pathogenicity on humansCene Gostinčar, Janja Zajc, Metka Lenassi, Ana Plemenitaš, Sybren de Hoog, Abdullah M. S. Al-Hatmi, Nina Gunde-Cimerman, 2018, original scientific article Abstract: Numerous agents of infections in humans and other mammals are found among fungi that are able to survive extreme environmental conditions and to quickly adapt to novel habitats. Nevertheless, the relationship between opportunistic potential and polyextremotolerance was not yet studied systematically in fungi. Here, the link between polyextremotol- erance and opportunistic pathogenicity is shown in a kingdom-wide phylogenetic analysis as a statistically significant co- occurrence of extremotolerance (e.g. osmotolerance and psychrotolerance) and opportunism at the level of fungal orders. In addition to extremotolerance, fungal opportunists share another characteristic%an apparent lack of specialised virulence traits. This is illustrated by a comparative genomic analysis of 20 dothideomycetous and eurotiomycetous black fungi. While the genomes of specialised fungal plant pathogens were significantly enriched in known virulence-associated genes that encode secreted proteases, carbohydrate active enzyme families, polyketide synthases, and non-ribosomal peptide synthetases, no such signatures were observed in human opportunists. Together the presented results have several implications. If infection of human hosts is a side effect of fungal stress tolerance and adaptability, the human body is most likely neither the preferred habitat of such species, nor important for their evolutionary success. This defines opportunism as opposed to pathogenicity, where infection is advantageous for the species% fitness. Since opportunists are generally incapable of the host-to-host transmission, any host-specific adaptations are likely to be lost with the resolution of the infection, explaining the observed lack of specialised virulence traits. In this scenario opportunistic infections should be seen as an evolutionary dead end and unlikely to lead to true pathogenicity.
Keywords: fungi, pathogenicity, infections in humans
Published in DiRROS: 24.07.2024; Views: 88; Downloads: 3376
Full text (2,85 MB)
This document has many files! More... |
6. Fifty Aureobasidium pullulans genomes reveal a recombining polyextremotolerant generalistCene Gostinčar, Martina Turk, Janja Zajc, Nina Gunde-Cimerman, 2019, original scientific article Abstract: The black yeast Aureobasidium pullulans is a textbook example of a generalistic and ubiquitous fungus thriving in a wide variety of environments. To investigate whether A. pullulans is a true generalist, or alternatively, whether part of its versatility can be attributed to intraspecific specialization masked by cryptic diversification undetectable by traditional phylogenetic analyses, we sequenced and analysed the genomes of 50 strains of A. pullulans from different habitats and geographic locations. No population structure was observed in the sequenced strains. Decay of linkage disequilibrium over shorter physical distances (<100 bp) than in many sexually reproducing fungi indicates a high level of recombination in the species. A homothallic mating locus was found in all of the sequenced genomes. Aureobasidium pullulans appears to have a homogeneous population genetics structure, which is best explained by good dispersal and high levels of recombination. This means that A. pullulans is a true generalist that can inhabit different habitats without substantial specialization to any of these habitats at the genomic level. Furthermore, in the future, the high level of A. pullulans recombination can be exploited for the identification of genomic loci that are involved in the many biotechnologically useful traits of this black yeast.
Keywords: black yeast, genome
Published in DiRROS: 24.07.2024; Views: 74; Downloads: 66
Full text (1,09 MB)
This document has many files! More... |
7. Genomic evidence of recombination in the basidiomycete Wallemia mellicolaSun Xiaohuan, Cene Gostinčar, Fang Chao, Janja Zajc, Hou Yong, Song Zewei, Nina Gunde-Cimerman, 2019, original scientific article Abstract: One of the most commonly encountered species in the small basidiomycetous sub-phylum Wallemiomycotina is Wallemia mellicola, a xerotolerant fungus with a widespread distribution. To investigate the population characteristics of the species, whole genomes of twenty-five strains were sequenced. Apart from identification of four strains of clonal origin, the distances between the genomes failed to reflect either the isolation habitat of the strains or their geographical origin. Strains from different parts of the world appeared to represent a relatively homogenous and widespread population. The lack of concordance between individual gene phylogenies and the decay of linkage disequilibrium indicated that W. mellicola is at least occasionally recombining. Two versions of a putative mating-type locus have been found in all sequenced genomes, each present in approximately half of the strains. W. mellicola thus appears to be capable of (sexual) recombination and shows no signs of allopatric speciation or specialization to specific habitats.
Keywords: population genomics, halotolerance, xerotolerance, basidiomycete, allergenic fungus, recombination
Published in DiRROS: 23.07.2024; Views: 126; Downloads: 61
 Link to full text
This document has many files! More... |
8. Stress-tolerant yeasts : opportunistic pathogenicity versus biocontrol potentialJanja Zajc, Cene Gostinčar, Anja Černoša, Nina Gunde-Cimerman, 2019, original scientific article Abstract: Stress-tolerant fungi that can thrive under various environmental extremes are highly desirable for their application to biological control, as an alternative to chemicals for pest management. However, in fungi, the mechanisms of stress tolerance might also have roles in mammal opportunism. We tested five species with high biocontrol potential in agriculture (Aureobasidium pullulans, Debayomyces hansenii, Meyerozyma guilliermondii, Metschnikowia fructicola, Rhodotorula mucilaginosa) and two species recognized as emerging opportunistic human pathogens (Exophiala dermatitidis, Aureobasidium melanogenum) for growth under oligotrophic conditions and at 37 °C, and for tolerance to oxidative stress, formation of biofilms, production of hydrolytic enzymes and siderophores, and use of hydrocarbons as sole carbon source. The results show large overlap between traits desirable for biocontrol and traits linked to opportunism (growth under oligotrophic conditions, production of siderophores, high oxidative stress tolerance, and specific enzyme activities). Based on existing knowledge and these data, we suggest that oligotrophism and thermotolerance together with siderophore production at 37 °C, urease activity, melanization, and biofilm production are the main traits that increase the potential for fungi to cause opportunistic infections in mammals. These traits should be carefully considered when assessing safety of potential biocontrol agents.
Keywords: opportunistic pathogen, biocontrol agent, virulence, stress tolerance, secretome, CAZy, protease, thermotolerance, oligotrophism, melanin, siderophore, biofilm
Published in DiRROS: 23.07.2024; Views: 110; Downloads: 126
Full text (2,70 MB)
This document has many files! More... |
9. Pitna voda v Mestni občini Ljubljana : pot od vodnega vira do kozarcaTadeja Kosec, Nina Gartner, Brigita Jamnik, Viviana Golja, Alenka Labovič, Lucija Smojver, Sabina Dolenec, Aljoša Šajna, Monika Novak Babič, Nina Gunde-Cimerman, Tinkara Kopar, 2019, professional monograph Keywords: centralni vodovodni sistem Ljubljana (CVS), pitna voda, materiali v stiku s pitno vodo, vzdrževanje sistemov, preskušanje, kovinski materiali, organski materiali, cementni materiali, mikrobiološki vpliv, certificiranje proizvodov, vodno gospodarstvo, oskrba z vodo
Published in DiRROS: 08.03.2024; Views: 347; Downloads: 166
Full text (4,02 MB)
This document has many files! More... |
10. |
