Nests of Marsh harrier (Circus aeruginosus L.) as refuges of potentially phytopathogenic and zoopathogenic fungi

Birds’ nests may be refuges for various species of fungi including that which are potentially phytopathogenic and zoopathogenic. Among the 2449 isolates of fungi obtained from nests of Marsh harriers 96.8% belonged to filamentous fungi. In total, 37 genera were identified from 63 fungi species. Within the mycobiotas of the examined nests populations of fungi which are potentially pathogenic for humans, homoiothermous animals and plants dominated. Among 63 species, 46 (72%) were potentially pathogenic fungi of which 18 species were potentially phytopathogenic and 32 species were pathogenic for homoiothermous animals. Inter alia species of fungi were found in the Marsh harriers nests: Aspergillus fumigatus, Aspergillus flavus, Scopulariopsis brevicaulis, Chrysosporium keratinophilum and Fusarium poae, Fusarium sporotrichioides. In terms of numbers, dominant in Marsh harrier nests were fungi pathogenic to birds, other homoiothermous animals and humans. On that basis it was concluded that Marsh harrier nests are both a source of fungal infections for that species and one of the links in the epidemiological cycle of opportunistic fungi for humans.     

An annotated checklist of pathogenic microorganisms associated with migratory birds

The potential for transport and dissemination of certain pathogenic microorganisms by migratory birds is of concern. Migratory birds might be involved in dispersal of microorganisms as their biological carriers, mechanical carriers, or as carriers of infected hematophagous ecto-parasites (e.g., ixodid ticks). Many species of microorganisms pathogenic to homeothermic vertebrates including humans have been associated with free-living migratory birds. Migratory birds of diverse species can play significant roles in the ecology and circulation of some arboviruses (e.g., eastern and western equine encephalomyelitis and Sindbis alphaviruses, West Nile and St. Louis encephalitis flaviviruses), influenza A virus, Newcastle disease virus, duck plague herpes-virus, Chlamydophila psittaci, Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Campylobacter jejuni, Salmonella enterica, Pasteurella multocida, Mycobacterium avium, Candida spp., and avian hematozoans. The efficiency of dispersal of pathogenic microorganisms depends on a wide variety of biotic and abiotic factors affecting the survival of the agent in, or disappearance from, a habitat or ecosystem in a new geographic area.     

Yeasts and filamentous fungi carried by the gynes of leaf-cutting ants

Insect-associated microbes exhibit a wide range of interactions with their hosts. One example of such interactions is the insect-driven dispersal of microorganisms, which plays an essential role in the ecology of several microbes. To study dispersal of microorganisms by leaf-cutting ants (Formicidae: Attini), we applied culture-dependent methods to identify the filamentous fungi and yeasts found in two different body parts of leaf-cutting ant gynes: the exoskeleton and the infrabuccal pocket. The gynes use the latter structure to store a pellet of the ants’ symbiotic fungus during nest founding. Many filamentous fungi (n = 142) and yeasts (n = 19) were isolated from the gynes’ exoskeleton. In contrast, only seven filamentous fungi and three yeasts isolates were recovered from the infrabuccal pellets, suggesting an efficient mechanism utilized by the gynes to prevent contamination of the symbiotic fungus inoculum. The genus Cladosporium prevailed (78%) among filamentous fungi whereas Aureobasidium, Candida and Cryptococcus prevailed among yeasts associated with gynes. Interestingly, Escovopsis, a specialized fungal pathogen of the leaf-cutting ant-fungus symbiosis, was not isolated from the body parts or from infrabuccal pellets of any gynes sampled. Our results suggest that gynes of the leaf-cutter ants Atta laevigata and A. capiguara do not vertically transmit any particular species of yeasts or filamentous fungi during the foundation of a new nest. Instead, fungi found in association with gynes have a cosmopolitan distribution, suggesting they are probably acquired from the environment and passively dispersed during nest foundation. The possible role of these fungi for the attine ant–microbial symbiosis is discussed.     

Ticks collected from migratory birds,including a new record of Haemaphysalis formosensis,on Jeju Island,Korea

Migratory birds may disperse parasites across ecological barriers, and recent climate change may alter the pattern of ectoparasite dispersal via changed patterns of bird migration. In order to document the parasitization of migratory birds by Ixodidae ticks on Jeju Island in Korea, we examined 934 migratory birds comprising 75 species for ticks from 2010 to 2012. In total, 313 ticks were collected from 74 migratory birds across 17 avian species and identified based on morphological keys. These ticks represented six species: Haemaphysalis flava, H. formosensis, H. longicornis, H. concinna, Ixodes turdus and I. nipponensis. Of particular note was the presence of H. formosensis, a species not previously reported to have been found in Korea, and H. concinna, which had not been previously reported on Jeju Island. The dominant tick species found were H. flava (226 ticks, 72.2 %) and I. turdus (54 ticks, 17.3 %), and ground-dwelling thrushes such as Pale thrushes (Turdus pallidus; 39 birds, 52.7 %) were the most important hosts. Although H. longicornis is the most abundant and prevalent terrestrial tick on Jeju Island, the species accounted for only 3.8 % of the total ticks collected in this study, suggesting that ticks on migratory birds may differ from the local tick fauna and that exotic ticks may be introduced via migratory birds. Therefore, long-term programs for tick and tick-borne disease surveillance are recommended to understand the role of migratory animals in the introduction of exotic species and associated pathogens and in life cycles of ticks at different stages in this region.     

Occurrence of Yeasts in Cloacae of Migratory Birds

Several species of yeast have been reported as pathogens in humans based on increases in immunodeficiency syndromes and as a result of immunosuppressant chemotherapy in cancer treatment. Domestic and wild birds are known to act as carriers of human pathogenic fungi. To gain additional information on the yeasts present in the cloacae of some species of migratory birds, 421 wild birds (24.39% out of 1726 birds caught in Romania, Hungary and Bulgaria) were sampled with the permission of the local judicial authority. The state of conservation of the birds (i.e. post-mortem alterations, colour of the mucosae etc.), along with their age and sex were determined. Samples were collected directly from the cloacae and cultured, and colonies were identified in each positive sample. Yeasts were isolated from 15.7% of the animals sampled, with the highest percentage found in coots (Fulica atra −58.8%) and the lowest in quails (Coturnix coturnix −1.7%). A total of 131 isolates belonging to 15 species of yeast were identified. Rhodotorula rubra was the yeast with the highest number of isolates (28.2%), followed by Cryptococcus albidus (18.4%), Candida albicans (9.2%), Trichosporon cutaneum (8.4%), Candida guilliermondii (6.1%), Candida tropicalis (6.1%) and other species. The present study represents the first survey on the occurrence of yeasts in the cloacae of migratory birds. The prevalence and species of yeasts isolated is discussed on the basis of the ecology, diet, and habitat of the birds.     

Black-headed gulls (<Emphasis Type="Italic">Chroicocephalus ridibundus</Emphasis>) - a natural reservoir of potentially pathogenic microfungi?

Mycological studies of selected populations of black-headed gulls were carried out in response to the increasing interest in wild birds as reservoirs of potentially pathogenic fungi and links in the epidemiological chain of mycoses hazardous to human and animals. The biological material comprised swabs from the beaks and cloacae of adult and young birds subjected to standard mycological diagnostics. 79.5% of samples were positive, comprising 22 fungal species belonging to 10 genera, mainly Candida, Rhodotorula, Aspergillus, Fusarium, Cryptococcus, and Trichosporon. The most frequently isolated species were Candida albicans and Rhodotorula rubra, found in the beaks of females and young birds and in the cloacae of young birds with comparable frequency. Cryptococcus laurentii, Cr. neoformans, Aspergillus niger, A. flavus, and Rh. muscilaginosa were isolated relatively frequently from all birds. The results highlight the ecological importance of wild birds in the circulation of potentially pathogenic fungi in the biosphere.     

Manganese superoxide dismutase in pathogenic fungi: An issue with pathophysiological and phylogenetic involvements

Manganese-containing superoxide dismutases (MnSODs) are ubiquitous metalloenzymes involved in cell defence against endogenous and exogenous reactive oxygen species. In fungi, using this essential enzyme for phylogenetic analysis of Pneumocystis and Ganoderma genera, and of species selected among Ascomycota, Basidiomycota and Zygomycota, provided interesting results in taxonomy and evolution. The role of mitochondrial and cytosolic MnSODs was explored in some pathogenic Basidiomycota yeasts (Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. gattii, Malassezia sympodialis), Ascomycota filamentous fungi (Aspergillus fumigatus), and Ascomycota yeasts (Candida albicans). MnSOD-based phylogenetic and pathogenic data are confronted in order to evaluate the roles of fungal MnSODs in pathophysiological mechanisms.     

Fungal community associated with marine macroalgae from Antarctica

Filamentous fungi and yeasts associated with the marine algae Adenocystis utricularis, Desmarestia anceps, and Palmaria decipiens from Antarctica were studied. A total of 75 fungal isolates, represented by 27 filamentous fungi and 48 yeasts, were isolated from the three algal species and identified by morphological, physiological, and sequence analyses of the internal transcribed spacer region and D1/D2 variable domains of the large-subunit rRNA gene. The filamentous fungi and yeasts obtained were identified as belonging to the genera Geomyces, Antarctomyces, Oidiodendron, Penicillium, Phaeosphaeria, Aureobasidium, Cryptococcus, Leucosporidium, Metschnikowia, and Rhodotorula. The prevalent species were the filamentous fungus Geomyces pannorum and the yeast Metschnikowia australis. Two fungal species isolated in our study, Antarctomyces psychrotrophicus and M. australis, are endemic to Antarctica. This work is the first study of fungi associated with Antarctic marine macroalgae, and contributes to the taxonomy and ecology of the marine fungi living in polar environments. These fungal species may have an important role in the ecosystem and in organic matter recycling.     

Fungal microbiota isolated from native stingless bee species inhibited pathogens of Apis mellifera

Social bees can establish interactions with microorganisms to keep their colonies free of pathogens and parasites by developing different protection strategies. We explored the fungal microbiota isolated from three species of stingless bees, Tetragonisca fiebrigi, Plebeias sp., and Scaptotrigona jujuyensis, and its potential ability to suppress pathogenic microorganisms of A. mellifera, namely Paenibacillus larvae, Ascosphaera apis and Aspergillus flavus, which were tested and evaluated. Six filamentous fungal strains, Trametes hirsuta, Alternaria alternata, Curvularia spicifera, Skeletocutis sp., Alternaria tenuissima, Monascus spp., as well as the yeast Wickerhamomyces anomalus, were selected for trials and isolated from the heads of foraging bees. The fungal strains were identified by macroscopic and microscopic taxonomic characteristics and by sequencing of the ITS1–5.8S–ITS2 region of ribosomal DNA. All fungal strains inhibited these pathogens of A. mellifera. We also evaluated the effect of the secondary metabolites extracted with and without ethanol. Both metabolites showed antimicrobial properties, and our results suggest that fungi isolated from stingless bees produce bioactive compounds with antibacterial and antifungal effects that could be used to treat Apis mellifera colony diseases and maintain colony health.     

Filamentous Fungi Associated with Bivalve Mollusks from Polluted Biotopes of Ussuriiskii Bay,Sea of Japan

We have studied for the first time the taxonomic composition of filamentous fungi associated with the bivalve mollusks Crenomytilus grayanus (Bunker, 1853) and Modiolus modiolus (Linnaeus, 1758), collected in polluted biotopes of Ussuriiskii Bay (Peter the Great Bay, Sea of Japan). One hundred fifty-five strains of higher fungi were isolated, and 35 species of filamentous fungi were identified. Out of these, 28 species were anamorphous fungi of the genera Aspergillus (12), Penicillium (10), Acremonium (1), Alternaria (1), Aureobasidium (1), and Cladosporium (3) (Deuteromycota), and 7 were species of the genera Chaetomium (6) and Myxotrichum (1) (Ascomycota). Twenty-four species of filamentous fungi were isolated from the internal organs of C. grayanus: 8 from the muscles, 8 from the hepatopancreas, 6 from the female gonads, 4 from the mantle, 3 from the kidneys and male gonads, and 1 from the gills. Twenty-one species of filamentous fungi were isolated from the internal organs of Modiolus modiolus: 10 from the muscles, 6 from the hepatopancreas, 5 from the female gonads, 3 from the kidneys, 3 from the mantle, and 1 from the gills. The bulk of the isolated species of the genera Aspergillus, Penicillium, Cladosporium, and Chaetomium were pathogenic and toxigenic fungi.     

Secretomes of medically important fungi reflect morphological and phylogenetic diversity

Secretome represents a main target for understanding the mechanisms of fungal adaptation. In the present study, we focus on the secretomes of fungi associated with infections in humans and other mammals in order to explore relationships between the diverse morphological and phylogenetic groups. Almost all the mammalian pathogenic fungi analyzed have secretome sizes smaller than 1000 proteins and, secreted proteins comprise between 5% and 10% of the total proteome. As expected, the correlation pattern between the secretome size and the total proteome was similar to that described in previous secretome studies of fungi. With regard to the morphological groups, minimum secretome sizes of less than 250 secreted proteins and low values for the fraction of secreted proteins are shown in mammalian pathogenic fungi with reduced proteomes such as microsporidia, atypical fungi and some species of yeasts and yeast-like fungi (Malassezia). On the other hand, filamentous fungi have significantly more secreted proteins and the highest numbers are present in species of filamentous fungi that also are plant or insect pathogens (Fusarium verticilloides, Fusarium oxysporum and Basidiobolus meristosporus). With respect to phylogeny, there are also variations in secretome size across fungal subphyla: Microsporidia, Taphrinomycotina, Ustilagomycotina and Saccharomycotina contain small secretomes; whereas larger secretomes are found in Agaricomycotina, Pezizomycotina, Mucoromycotina and Entomophthoromycotina. Finally, principal component analysis (PCA) was conducted on the complete secretomes. The PCA results revealed that, in general, secretomes of fungi belonging to the same morphological group or subphyla cluster together. In conclusion, our results point out that in medically important fungi there is a relationship between the secretome and the morphological group or phylogenetic classification.     

Leaf-cutting ants: an unexpected microenvironment holding human opportunistic black fungi

Fungus-growing ants of the genus Atta are known for their leaf-cutting habit, a lifestyle they have maintained since their 50-million-year-old co-evolution with a mutualistic fungus, cultivated as food. Recent studies have highlighted that, in addition to the mutualistic fungus, nests of ants harbor a great diversity of microbial communities. Such microorganisms include the dematiaceous fungi, which are characterized by their melanized cell walls. In order to contribute to the knowledge of fungal ecology, as well as opportunistic strains that may be dispersed by these social insects, we isolated and identified fungi carried by gynes of Atta capiguara and Atta laevigata, collected from colonies located in Fazenda Santana, Botucatu (São Paulo, Brazil). The isolation was carried out using the oil flotation technique, which is suitable for the growth of black fungi. Inoculated plates were incubated at 25 and 35 °C until black cultures were visible (20–45 days). Isolates were identified based on microscopic and molecular characteristics. Some isolated genera were: Cladophialophora, Cladosporium, Exophiala, Ochroconis, Phaeococcomyces, Phialophora and Penidiella. Hyaline species were also found. The results obtained from this work showed that leaf-cutting gynes may contribute to the dispersal of opportunistic dematiaceous fungi. It is suggested that more attention should be paid to this still unexplored subject.     

Cyclophilin acts as a ribosome biogenesis factor by chaperoning the ribosomal protein (PlRPS15) in filamentous fungi

The rapid transport of ribosomal proteins (RPs) into the nucleus and their efficient assembly into pre-ribosomal particles are prerequisites for ribosome biogenesis. Proteins that act as dedicated chaperones for RPs to maintain their stability and facilitate their assembly have not been identified in filamentous fungi. PlCYP5 is a nuclear cyclophilin in the nematophagous fungus Purpureocillium lilacinum, whose expression is up-regulated during abiotic stress and nematode egg-parasitism. Here, we found that PlCYP5 co-translationally interacted with the unassembled small ribosomal subunit protein, PlRPS15 (uS19). PlRPS15 contained an eukaryote-specific N-terminal extension that mediated the interaction with PlCYP5. PlCYP5 increased the solubility of PlRPS15 independent of its catalytic peptide-prolyl isomerase function and supported the integration of PlRPS15 into pre-ribosomes. Consistently, the phenotypes of the PlCYP5 loss-of-function mutant were similar to those of the PlRPS15 knockdown mutant (e.g. growth and ribosome biogenesis defects). PlCYP5 homologs in Arabidopsis thaliana, Homo sapiens, Schizosaccharomyces pombe, Sclerotinia sclerotiorum, Botrytis cinerea and Metarhizium anisopliae were identified. Notably, PlCYP5-PlRPS15 homologs from three filamentous fungi interacted with each other but not those from other species. In summary, our data disclosed a unique dedicated chaperone system for RPs by cyclophilin in filamentous fungi.     

Environmental characteristics and taxonomy of microscopic fungi isolated from washing machines

Washing machines (WMs) are convenient places for fungal colonization. This study is focused on fungal diversity of WMs, and investigates relationships between habits of WM users and colonising species. Housekeeping conditions and habits were assessed in Hungary with a questionnaire. Several fungal species were identified by microscopy and sequence analysis of diagnostic loci. Based on the results, 32 % of the sampled WMs were highly polluted with various species of fungi. Forty six percent of them were colonised also by opportunistically human pathogenic species. In total, 32 yeast and 39 filamentous fungal strains were isolated. Growth tests were conducted with five selected taxa (Cutaneotrichosporon dermatis, Cystobasidium slooffiae, Meyerozyma guilliermondii, Candida parapsilosis and the Fusarium oxysporum species complex (FOSC)) to ascertain their tolerance ranges. None of the examined isolates were able to grow >50 °C, 4.10 < pH < 10.88. FOSC could grow at high salinity. More species were detected in WMs operated in rooms without heating systems (p = 0.0025). The number of species was higher in WMs located in the kitchen than the ones kept in bathroom or in other rooms (p = 0.0205). WMs may serve as a reservoir of pathogenic fungi, the presence of which may depend on the usage of these devices.     

Filamentous fungi in the epibiosis of the scallop Mizuhopecten yessoensis (Bivalvia) in Peter the Great Bay, Sea of Japan

This study considers the taxonomic composition of filamentous fungi in the epibiosis on the shell of the Yesso scallop Mizuhopecten yessoensis (Jay, 1856) (Bivalvia), which were collected in open waters of Peter the Great Bay, Sea of Japan. The taxonomic composition was found to include ten species of filamentous fungi, nine of which were identified. The revealed species belong to six genera, viz., Aspergillus, Aphanocladium, Cladosporium, Penicillium, Phialophorophoma, and Eurotium.     

Long-distance endozoochorous dispersal of submerged macrophyte seeds by migratory waterbirds in northern Europe—a critical review of possibilities and limitations

We review whether migratory Anatidae, i.e., swans, geese and ducks, could be acting as vectors for dispersal of Zostera, Ruppia and Potamogeton propagules by endozoochory (carrying seeds in their guts). We list six prerequisites that must all be fulfilled, if successful dispersal should occur. Several Anatidae species feed on these macrophytes, and undertake rapid long-distance movements, making dispersal possible. We identify four problems, which in combination leads us to conclude that long-distance dispersal events are likely to be rare. (i) Most long-distance movements are out of phase with the reproductive efforts of the plants, and if birds arrive at sites when plants still bear seeds, they are likely to depart well after seed stocks have been depleted. (ii) Seed transport by birds will usually be uni-directional, from north to south on autumn migrations. (iii) Most of the gut contents of migratory birds are likely to have been discarded within 300 km of departure. (iv) In many cases, birds will arrive in habitats seriously different from those they departed, i.e., any seeds carried along will have low chances of surviving in their new site. We suggest that northbound dispersal by endozoochory can only occur during spring if waterbirds feed on seeds that have not been depleted and remained frozen down or buried in sediments, or during moult- or post-moult migrations. Moult migration takes place in summer in phase with the reproductive efforts of the plants. Also epizoochorous dispersal (external attachment) is subject to restrictions i, ii and iv.     

Quantitative analysis of phytopathogenic ascomycota on leaves of pedunculate oaks (Quercus robur L.) by real-time PCR

Leaves of oak trees are often infected by various pathogenic fungi. As it is difficult to remove such organisms quantitatively from the leaf surface and as it is often impossible to grow these organisms independently from their host, there are almost no molecular data available from these oak leaf specific pathogens. For the quantitative removal of the microorganisms a procedure was developed combining a wax and microorganism freezing method with a DNA extraction technique. For the development of a species specific detection, DNA of pathogenic filamentous fungi was isolated from hyphae of the upper leaf surface of Quercus robur. Three different species could be identified as (i) Cladosporium sp., (ii) Ramularia sp. and (iii) Microsphaera alphitoides by amplifying and sequencing an 18S-28S segment of their rDNA. For the final quantification a real-time PCR protocol was established allowing the species specific quantification of the three pathogenic filamentous fungi. The whole procedure was successfully applied to quantify the amount of the three species on oak leaves collected in autumn.     

Different contributions of birds and mammals to seed dispersal of a fleshy-fruited tree

Birds and mammals are important seed dispersers of fleshy-fruited plants. Although their behaviors are different, they frequently consume the same species. Thus to understand the dispersal of fleshy-fruited plants, the contribution of birds and mammals to seed dispersal has to be evaluated. Besides, within birds or mammals, some species may functionally different from others. In this study, we examined seed dispersal of the fleshy-fruited tree Swida controversa focusing on the difference between two frugivore groups (birds and mammals), and differences between species within groups. Collected seeds and S. controversa trees were identified using simple sequence repeat (SSR) genotyping, thus enabling to determine the distance between mother tree and dispersed seeds. The avian species were identified by DNA barcoding of feces, whereas the mammalian species were identified by the shape and smell of feces. Most seeds that fell near or under the maternal trees were dispersed by birds, resulting in short seed dispersal distances (average, 13 m). DNA barcoding detected five taxa of avian dispersers. No differences were detected in seed dispersal distance by different avian taxa (i.e., the distance between dispersed seeds and their maternal trees within the research plot); however the rate of seed immigration from outside the research plot by some avian taxa varied significantly. The seed dispersal distance by mammals was significantly further (127 m; min > 50 m) than that by birds. Additionally, immigrated seeds accounted for approximately two-thirds of mammal-dispersed seeds, indicating that these seeds were from outside the research plot, and that mammals significantly contributed to the long-distance seed dispersal of S. controversa. No differences in seed dispersal distance were detected between different mammalian taxa. Overall, this study revealed that birds and mammals show clearly different seed dispersal patterns, and thus, they play different roles in the regeneration of S. controversa.     

Wood-inhabiting insects can function as targeted vectors for decomposer fungi

Most wood-inhabiting fungi are assumed to be dispersed primarily by wind, with the exception of a few species involved in mutualistic relationships with insects. In this study we tested whether several species of wood-inhabiting insects can function as dispersal vectors for non-mutualistic fungi, which would indicate that wood-inhabiting fungi can benefit from targeted animal-mediated dispersal. We sampled wood-inhabiting beetles (Coleoptera) from freshly felled wood experimentally added to forests and used DNA metabarcoding to investigate the fungal DNA carried by these insects. Staphylinid beetles rarely contained fungal DNA, while Endomychus coccineus, Glischrochilus hortensis and Glischrochilus quadripunctatus frequently carried fungal DNA with a composition specific to the insect taxon. A large proportion of the obtained fungal sequences (34%) represented decomposer fungi, including well-known wood-decay fungi such as Fomitopsis pinicola, Fomes fomentarius, Trichaptum abietinum and Trametes versicolor. Scanning electron microscopy further showed that some of the fungal material was carried as spores or yeast cells on the insect exoskeletons. Our results suggest that insect-vectored dispersal is of broader importance to wood-inhabiting fungi than previously assumed.