Study of airborne fungus spores by viable and non-viable methods in Havana,Cuba

The Havana aeromycobiota diversity was studied from November 2010 to October 2011 using two complementary volumetric methods. A total of 35 fungal genera were characterised, 26 of them were recognised only by non-viable methods, six with viable methodology and the other three with both sampling methods. Furthermore, 47 species were identified by cultivation and the spores collected with the non-viable methodology. These could not be included in a specific genus, and thus, were categorised into five fungal types. In general, the main, spread worldwide, mitosporic fungi also predominated the Havana atmosphere. The predominant species were Cladosporium cladosporioides, Aspergillus flavus and Penicillium citrinum. Moreover, several Zygomycetes (Syncephalastrum racemosum, Rhizopus stolonifer and Rhizopus oryzae), Ascomycetes (Chaetomium globosum) and Basidiomycetes such as Coprinus or Ganoderma were isolated. In the present paper, the review of the airborne fungi conducted in previous studies in Cuba was completed by the detection of two new genera and the first isolation of ten new records in the Cuban atmosphere. Most of the fungi detected showed a diurnal pattern with high spore peak at 11.00–12.00.     

Airborne pollen and fungal spores in Garki,Abuja (North-Central Nigeria)

The ambient atmosphere is dominated with pollen and spores, which trigger allergic reactions and diseases and impact negatively on human health. A survey of pollen and fungal spores constituents of the atmosphere of Garki, Abuja (North-Central Nigeria) was carried out for 1 year (June 1, 2011–May 31, 2012). The aim of the study was to determine the prevalence and abundance of pollen and fungal spores in the atmosphere and their relationship with meteorological parameters. Airborne samples were trapped using modified Tauber-like pollen trap, and the recipient solutions were subjected to acetolysis. Results revealed the abundance of fungal spores, pollen, fern spores, algal cysts and diatoms in decreasing order of dominance. The atmosphere was qualitatively and quantitatively dominated by pollen during the period of late rainy/harmattan season than the rainy season. Numerous fungal spores were trapped throughout the sampling periods among which Alternaria spp., Fusarium spp., Cladosporium spp. and Curvularia spp. dominated. These fungi have been implicated in allergic diseases and are dermatophytic, causing diverse skin diseases. Other pathogenic fungi found in the studied aeroflora were Dreschlera spp., Helminthosporium spp., Torula spp., Pithomyces spp., Tetraploa spp., Nigrospora ssp., Spadicoides spp., Puccinia spp. and Erysiphe graminis. Total pollen and fungal spores counts do not show significant correlation with meteorological parameters.     

Airborne fungi monitoring in Santiago, Chile

Fungal airborne spores were studied from September 1996throughout August 1997 in Santiago, Chile. Total concentrationsfluctuated between 308 and 10,334 spores/m³/day withan annual mean of 2,154 per m³, the highest dispersion beingduring April and May. Forty-five percent of total fungal content wasfound in autumn. Thirteen genera and 3 other spore types wereidentified. Cladosporium, the most abundant genera in ouratmosphere, contributed with 70.9% of the total fungi counts andreached an annual mean of 1,527 spores/m³/day, itshighest frequency being in autumn. Alternaria appeared as thesecond most frequent genera, with an annual mean of 40spores/m³/day, representing a 1.9% of theannual fungal catch. Altogether, Stemphylium, Torula, Epicoccum,Ganoderma, Helminthosporium, Chaetomiun, Pleospora and othersreached relative frequencies of 0.5% or less. It is concludedthat fungi are present in Santiago's atmosphere all year round, some ofthem with a clear seasonality.     

Prevalence of culturable and non-culturable airborne fungi in a grain store in Delhi

Fungal spores are important aeroallergens and proper knowledge of their qualitative and quantitative prevalence in indoor and outdoor environments is of paramount importance in the study of allergic disorders. The present investigation was aimed at the study of seasonal and annual prevalence of fungi inside a large grain storage facility. Sampling was carried out from September 1989 to August 1991. Although fungal spores occurred throughout the year there was seasonal variation.Aspergillus flavus. Cladosporium spp.Epicoccum nigrum and basidiospores had a definite seasonal pattern.Aspergillus flavus andUstilago (smuts) were the most predominant fungi in the facility. Their concentration was significantly higher (P<0.05) than in outside air. The need to reduce fungal concentration in grain storage is emphasised.     

Fertile fungal spores collected on different faced surfaces in the atmosphere of Giza,Egypt

A quantitative and qualitative survey was carried out for airborne fungus spores coming into contact with horizontally and vertically gravitation sampling oriented surfaces in the atmosphere of Giza city. Czapek Dox agar, malt extract agar, potato dextrose agar and Sabouraud dextrose agar Petri dishes were exposed monthly to the five oriented surfaces of a polystyrene cube, throughout a one-year period. Significant differences (P < 0.01) were observed between the total counts of caught airborne fungi contacting with the horizontal compared to other vertically oriented surfaces. Conversely, there were no significant differences observed between the total catch of airborne fungi using the various sampling media. The results revealed that vertical sampling provides valuable information that may be lost from horizontal sampling alone. A total of 5,053 colonies belonging to 40 fungal organisms were identified. Alternaria (24.26%), Aspergillus (19.2%), Cladosporium (14.5%) and Penicillium (11.43%) were the most predominant fungal genera. Collected fungi were grouped into high, medium, low and rare components depending upon their frequency in the studied atmosphere. Aspergillus niger, Aspergillus parasiticus, Alternaria, Cladosporium and Penicillium were regularly found on all oriented surfaces. However, Arthrobotrys, Biospora, Chaetomium, Pleospora, Trichothecium and Verticillium were rarely found in the air. Positive and/or negative correlations were observed between the total fungal counts and the predominant fungal types with meteorological parameters during sampling days.     

Status of airborne spores and pollen in a coir factory in Kerala,India

The prevalence of airborne fungal spores and pollen grains in the indoor and outdoor environments of a coir factory in Thiruvananthapuram district of Kerala state, India was studied using the Burkard Personal Sampler and the Andersen 2-stage Sampler for 2 years (September 1997 to August 1999). The concentration of pollen grains was remarkably lower than that of fungal spores (ratio of 1:28). There was no large difference in the concentrations and types of fungal spores between the indoor and outdoor environments, with 26 spore types found to be present indoors and 27 types outdoors; of these, 22 were common to both the environments. Aspergillus/Penicillium, Cladosporium, ‘other basidiospores’ and ascospores were the dominant spore types. The total spore concentration was highest in February and lowest in September, and it was significantly higher in 1998–1999 than in 1997–1998. Twenty viable colony-forming types were isolated from inside the coir factory. The most dominant viable fungi isolated were Penicillium citrinum, Aspergillus flavus and Aspergillus niger. The total pollen concentration was higher in the outdoor environment of the coir factory than indoors, with 15 and 17 pollen types, respectively. Grass and Cocos nucifera pollen types were dominant. The dominant spore and pollen types trapped in the two environments of the coir factory are reportedly allergenic and, consequently, workers are at risk of catching respiratory/allergic diseases.     

Study of airborne fungal spores in Madrid, Spain

The concentration of fungal spores in the atmosphere of Madrid was recorded and analyzed for the year 2003. Airborne spores were sampled continuously with a Hirst-type spore trap located on the roof of a building of the School of Pharmacy, at about 8 m above ground level. Correlation between the mean daily spore concentrations and meteorological variables were explored by means of Spearman’s correlation analyses. Seventy spore types were identified, of which the most numerous were Cladosporium, Aspergillaceae (conidia), Coprinus, Agaricales (basidiospores), Ustilago (teliospores) and Pleospora (ascospores). These six types of spores represented more than 70% of the total. Cladosporium represented 41% of the total fungal spores, while Ustilago spores, the concentrations of which in May and June exceeded 47% of the monthly total spore count, constituted the second most important group. Spores reached their highest concentrations in the spring months, and in the autumn, mainly in October. A␣positive significant correlation was found between airborne spore counts and temperature and relative humidity. The results provide a picture of the spectrum of airborne fungal spores present in the atmosphere of Madrid and of the `peak' periods of their presence. Future studies will provide more detailed information on the seasonal dynamics of the spores most frequently found in the air as well as on the extent to which atmospheric conditions influence their release, dispersion and sedimentation processes.     

The different morphologies of yeast and filamentous fungi trigger distinct killing and feeding mechanisms in a fungivorous amoeba

Size and diverse morphologies pose a primary challenge for phagocytes such as innate immune cells and predatory amoebae when encountering fungal prey. Although filamentous fungi can escape phagocytic killing by pure physical constraints, unicellular spores and yeasts can mask molecular surface patterns or arrest phagocytic processing. Here, we show that the fungivorous amoeba Protostelium aurantium was able to adjust its killing and feeding mechanisms to these different cell shapes. Yeast-like fungi from the major fungal groups of basidiomycetes and ascomycetes were readily internalized by phagocytosis, except for the human pathogen Candida albicans whose mannoprotein coat was essential to escape recognition by the amoeba. Dormant spores of the filamentous fungus Aspergillus fumigatus also remained unrecognized, but swelling and the onset of germination induced internalization and intracellular killing by the amoeba. Mature hyphae of A. fumigatus were mostly attacked from the hyphal tip and killed by an actin-mediated invasion of fungal filaments. Our results demonstrate that predatory pressure imposed by amoebae in natural environments selects for distinct survival strategies in yeast and filamentous fungi but commonly targets the fungal cell wall as a crucial molecular pattern associated to prey and pathogens.     

The incidence of fungal spores in the ambient air and inside homes: Evidence from London

Little research has been carried out in London concerning fungal spore prevalence yet this information may help to elucidate geographical patterns of asthma and hay fever. Although many types of spore reach peak concentrations outdoors in late-summer, the incidences in the indoor environment may be more important through the winter because of heating and poor ventilation. Daily average concentrations of fungal spores in the ambient atmosphere were monitored with a Burkard volumetric spore trap on an exposed roof in North London from autumn 1991 until the summer of 1992. Indoor spore measurements were taken in 19 homes in the vicinity through the winter months, both by direct air sampling using a portable Burkard sampler and by dust culture. Trends in the occurrence and concentrations of fungal spores indoors and outdoors were examined. Relationships between the abundance of selected allergenic fungi and features of the houses were analysed including age of dwelling, dampness, cleanliness and presence of pets.Aspergillus andPenicillium were the most frequently occurring spore types in the homes. Overall, high spore incidence was associated with dampness and dust accumulation. The outdoor spore samples revealed generally low concentrations through the winter until March when concentrations of many types includingCladosporium, Epicoccum andAlternaria increased in abundance in response to the warmer weather. Even during the late-spring and early-summer, concentrations of most fungal spores were notably below those reported for rural sites.     

Allergic potential of someAspergilli on saw mill workers in Lucknow,India

Fifty fungal types were isolated from the indoor atmosphere of saw mills by exposing Petri plates containing Czapek-dox Agar, Potato-dextrose Agar and Sabouraud Agar media for 5 min. The fungal flora of the outdoor surroundings was also studied for comparison. Species ofAspergilli dominated in the saw mills, being represented by 16 species including one ascosporic form. Other fungi were species ofCladosporium, Alternaria, Curvularia, Penicillium, Fusarium, etc. Variations in the fungal population in different months were also observed. Fungal spores recovered using the Rotorod Sampler wereAlternaria, Curvalaria lunata, Curvularia tetramera, Cladosporium, Dreschslera sp.,Epicoccum sp.,Pithomyes sp.,Nigrospora, Stemphylium sp. andTorula sp. Mycelial fragments and unidentifiable spores were also seen in abundance. Varying allergic responses of patients were also recorded by testing intradermally, the antigens of nineAspergilli, vizAspergillus flavus, A. fumigatus, A. japonicus, A. melleus, A. nidulans, A. niger, A. niveus, A. tammarii and A. terreus.     

Contribution of leaf surface fungi to the air spora

High concentrations of airborne fungal spores frequently occur from spring through fall in temperate areas of the world. Although it is generally assumed that fungi on leaf surfaces are contributors to the air spora, little data are available comparing the types of fungi found on leaf surfaces with those in the atmosphere. Air sampling was carried out with a Burkard Spore Trap located on the roof of a building on the University of Tulsa campus using standard methods. Leaf samples were aseptically collected from Ulmus americana and Quercus palustris trees on campus, placed in sterile plastic bags, and brought to the lab. For each leaf, 4 cm² areas of both upper and lower leaf surfaces were swabbed and plated on malt extract agar with streptomycin. Cultures were incubated at room temperature for 5–7 days and then examined microscopically. Results were expressed as colony forming units (CFU)/cm². Twenty-one fungal taxa were identified from the air samples. The most abundant taxa were Cladosporium, ascospores, basidiospores, and Alternaria; together these four spore types comprised over 90% of the yearly total. Yeasts were the most abundant fungi isolated from both leaf types. Among the mycelial fungi were Phoma species, followed by Cladosporium and Alternaria. Overall twenty genera of filamentous fungi were identified. Yeasts and Phoma are normally splash dispersed and were not identified in the Burkard air samples. However, 10 taxa isolated from leaf surfaces were registered in air samples. Crude estimates of the leaf surface area of each tree suggest that the total fungal load was approximately 5.04×10⁸ CFU for Ulmus and 2.71×10⁸ CFU for Quercus. Of these levels, 19% were from fungi also detected in air samples. The data suggest that some leaf-surface fungi are major contributors to the air spora.     

Allergic potential of someAspergilli on saw mill workers in Lucknow,India

Fifty fungal types were isolated from the indoor atmosphere of saw mills by exposing Petri plates containing Czapek-dox Agar, Potato-dextrose Agar and Sabouraud Agar media for 5 min. The fungal flora of the outdoor surroundings was also studied for comparison. Species ofAspergilli dominated in the saw mills, being represented by 16 species including one ascosporic form. Other fungi were species ofCladosporium, Alternaria, Curvularia, Penicillium, Fusarium, etc. Variations in the fungal population in different months were also observed. Fungal spores recovered using the Rotorod Sampler wereAlternaria, Curvalaria lunata, Curvularia tetramera, Cladosporium, Dreschslera sp.,Epicoccum sp.,Pithomyes sp.,Nigrospora, Stemphylium sp. andTorula sp. Mycelial fragments and unidentifiable spores were also seen in abundance. Varying allergic responses of patients were also recorded by testing intradermally, the antigens of nineAspergilli, vizAspergillus flavus, A. fumigatus, A. japonicus, A. melleus, A. nidulans, A. niger, A. niveus, A. tammarii and A. terreus.     

Presence in the atmosphere of vine and tomato pathogens

Summary In nature fungi, together with bacteria, play an important role in the degradation of organic substances. A small group of fungi is responsible for mycosis in man and animals. A larger group made up of different fungal taxa are particularly harmful to crops. The study of agricultural fungal phytopathologies is more difficult in that many taxa are characterized by a high degree of nutritional specialization. The identification in the field of the diseases caused by these taxa takes place often too late and not always are they controllable at a specific stage of their evolution. Since the majority of fungal spores is airborne and consequently present in various concentrations at different altitudes in the atmosphere, it is possible to monitor them and sometimes identify the fungus by sampling the air with a volumetric spore trap. Its diagnostic use has allowed to samplePlasmopara sporangia and obtain their concentration/m³ in the air of a vineyard. Similar results have been obtained in tomato fields, with the identification ofPhytophthora sporangia, the presence of which has been correlated to the meteorological data of the trial period. Field monitoring also offers the possibility of evaluating the presence of other fungi such as the generaBotrytis, Oidium, Alternaria, Pyricularia, Fusarium andStemphylium which damage crops.     

Airborne fungal spores in an industrial area: seasonal and diurnal periodicity

Qualitative and quantitative studies of atmospheric fungal spores at a chloralkali factory, Jayashree Chemicals. were made during 1993 employing culture plate and rotorod methods. A total of 57 sporulating fungal types, including three sterile mycelial forms, were recorded by the culture plate method and 51 spore types, including the hyphal fragments and unidentified spores, were recorded by the rotorod method. As to the seasonal variation, winter was found to be the greatest contributor of fungal spores as compared to the summer and rainy season. Instead, when considering the hour of the day, the peak number of fungal propagules was recorded at noon (12.00 h) followed by evening and morning values, an exception being recorded in winter months, when maximum CFUs ofCladosporium were monitored in the morning. The seasonal variation in fungal concentration and composition was found to be influenced by temperature, rainfall and relative humidity, whereas diurnal incidence was the effect of varying temperature and relative humidity during day time only. Moderate temperature and relative humidity favoured the maximum fungal spore load in the atmosphere.Cladosporium, Nigrospora, Alternaria, Lasiodiplodia, Drechslera, Pestalotia, Curvularia, Epicoccum, Aspergillus, Penicillium andChaetomium were the commonest fungal spores in the factory area.     

Glomalean mycorrhizal fungi from tropical Australia

 A comparison of different methods for isolation of vesicular-arbuscular mycorrhizal (VAM) fungi into open-pot cultures was undertaken as part of a study of the diversity of these fungi. Four different isolation techniques using spores separated from soil, soil trap cultures, root samples, or transplanted seedlings grown in intact soil cores were used to obtain as many fungi as possible from each site. Isolation methods were compared using paired samples from the same locations within natural (savanna, rocky hill, wetland, rainforest) and disturbed (minesite) habitats in a seasonally dry tropical region in the Northern Territory of Australia. There were large differences in (i) the efficiency (rate of increase in mycorrhizal colonisation), (ii) the proportion of successful cultures, (iii) fungal diversity (number of fungal species in each culture) and (iv) specificity (identity of species isolated) between these four procedures. However, the less-efficient procedures generally resulted in a higher proportion of cultures of one fungus, which could be used without further isolation steps. Most species of Scutellospora, Acaulospora and Gigaspora were obtained primarily from field-collected spores, but only 50% of these culture attempts were successful. Spores from these initial cultures produced mycorrhizas much more rapidly and successfully when used to start second-generation cultures. Several species of fungi, rarely recovered as living spores from field soils, were dominant in many trap cultures started from soil or roots. Most of these fungi were Glomus species, that were first distinguished by colonisation patterns in roots and eventually identified after sporulation in second- or third-generation trap cultures. These experiments demonstrated that glomalean fungi in the habitats sampled belonged to two functional categories, based on whether or not spores were important propagules. The "non-sporulating" fungi were dominant in many trap cultures, which suggests that these fungi had higher total inoculum levels in soils than other fungi. Pot-culturing methods provided additional information on fungal diversity which complemented spore occurrence data obtained using the same soil samples and provided valuable new information about the biology of these fungi. Accepted: 26 December 1998     

Arbuscular mycorrhizal structure and fungi associated with mosses

We investigated the colonization and diversity of arbuscular mycorrhizal (AM) fungi associated with 24 moss species belonging to 16 families in China. AM fungal structures, i.e. spores, vesicles, hyphal coils (including intracellular hyphae), or intercellular nonseptate hyphae, were found in 21 moss species. AM fungal structures (vesicles, hyphal coils, and intercellular nonseptate hyphae) were present in tissues of 14 moss species, and spores and nonseptate hyphae on the surface of gametophytes occurred in 15 species. AM fungal structures were present in 11 of the 12 saxicolous moss species and in six of the ten terricolous moss species, but absent in two epixylous moss species. AM fungal structures were only observed in moss stem and leaf tissues, but not in rhizoids. A total of 15 AM fungal taxa were isolated based on trap culture with clover, using 13 moss species as inocula. Of these AM fungi, 11 belonged to Glomus, two to Acaulospora, one to Gigaspora, and one to Paraglomus. Our results suggest that AM fungal structures commonly occur in most mosses and that diverse AM fungi, particularly Glomus species, are associated with mosses.     

Molecular and functional characterization of endophytic fungi from traditional medicinal plants

This study reports the isolation of 63 endophytic fungal isolates from two traditional medicinal plants, Ocimum sanctum and Sapindus detergens from different locations of Amritsar, India. The functional characterization of the fungi for their ability to produce anti bacterial and anti cancer agent was carried out. Sixteen strains were characterized at molecular level by sequencing the amplified ITSI-5.8-ITSII region of rDNA. The phylogenetic tree resolved the endophytic fungi into different clades. The fungal endophytes belonging to order Pleosporales (Alternaria sp., Phoma sojicola and Exserohilum sp.) were functionally versatile as they produced diverse biomolecules including antibacterial agent active against Mycobacterium smegmatis, as well as cytotoxic activity against different human cancer cell lines of lung, ovary, breast, prostrate, neuroblastoma and colon.     

Main airborne Ascomycota spores: characterization by culture, spore morphology, ribosomal DNA sequences and enzymatic analysis

The aim of this work was to identify the main allergy-related Ascomycetes fungal spores present in the atmosphere of Porto, using different and complementary techniques. The atmospheric sampling, performed in the atmosphere of Porto (Portugal) from August 2006 to July 2008, indicated Cladosporium, Penicillium, Aspergillus and Alternaria as the main fungal spore taxa. Alternaria and Cladosporium peaks were registered during summer. Aspergillus and Penicillium highest values were registered from late winter to early spring. Additionally, the Andersen sampler allowed the culture and isolation of the collected viable spores subsequently used for different identification approaches. The internal-transcribed spacer region of the nuclear ribosomal repeat unit sequences of airborne Ascomycetes fungi isolates revealed 11 taxonomically related fungal species. Among the identified taxa, Penicillum and Aspergillus presented the highest diversity, while only one species of Cladosporium and Alternaria, respectively, were identified. All selected fungal spore taxa possessed phosphatase, esterase, leucine arylamidase and β-glucosidase enzymatic activity, while none had lipase, cystine arylamidase, trypsin or β-glucuronidase activity. The association between the spore cell wall morphology, DNA-based techniques and enzymatic activity approaches allowed a more reliable identification procedure of the airborne Ascomycota fungal spores.     

The aerobiological significance of smut spores in Tulsa,Oklahoma

Few aerobiological studies have focused on smut spores, teliospores of fungi within the order Ustilaginales, but the scientific literature provides evidence of the potential aerobiological significance of these plant pathogens. The atmosphere in Tulsa, Oklahoma was monitored for the presence of smut teliospores using a Burkard Volumetric Spore Trap. Smut spores were identified in the atmospheric samples every day from May to October during 1991 and 1992 at concentrations that were normally below 1000 spores/m³. The peak concentration observed during this study was almost 6000 spores/m³. Daily concentrations fluctuate due to a variety of factors such as precipitation, relative humidity, percent sunshine, and the phenology of fungi in relation to their hosts. In northeastern Oklahoma, the most prevalent species of smuts in the atmosphere during the spring includeSphacelotheca occidentalis, Ustilago tritici, andU. kolleri. In the fall, spores ofU. brumivora, U. bullata, andU. maydis are more common.     

The aerobiological significance of smut spores in Tulsa,Oklahoma

Few aerobiological studies have focused on smut spores, teliospores of fungi within the order Ustilaginales, but the scientific luterature provides evidence of the potential aerobiological significance of these plant pathogens. The atmosphere in Tulsa, Oklahoma was monitored for the presence of smut teliospores using a Burkard Volumetric Spore Trap. Smut spores were identified in the atmospheric samples every day from May to October during 1991 and 1992 at concentrations that were normally below 1000 spores/m³. The peak concentration observed during this study was almost 6000 spores/m³. Daily concentrations fluctuate due to a variety of factors such as precipitation, relative humidity, percent sunshine, and the phenology of fungi in relation to their hosts. In northeastern Oklahoma, the most prevalent species of smuts in the atmosphere during the spring includeSphacelotheca occidentalis, Ustilago tritici, andU. kolleri. In the fall, spores ofU. brumivora, U. bullata, andU. maydis are more common.