H.G. Neumeister-Kemp

Mycosphaerella species associated with Eucalyptus in south-western Australia: new species, new records and a key

Mycosphaerella ambiphylla sp. nov. (anamorph: Phaeophleospora) and Mycosphaerella aurantia sp. nov., are described from diseased Eucalyptus globulus leaves. In addition, a new fungal record in Australia, M. mexicana, and two new records for Western Australia, M. gregaria and M. parva, are discussed. A key is provided to Mycosphaerella species on E. globulus in Western Australia.

Changes in airborne fungi from the outdoors to indoor air; large HVAC systems in nonproblem buildings in two different climates

Little is known about the changes in occurrence and distribution of airborne fungi as they are transported in the airstream from the outdoor air through the heating, ventilation, and air conditioning (HVAC) system to the indoor air. To better understand this, airborne fungi were analyzed in the HVAC systems of two large office buildings in different climate zones. Fungal samples were taken in each of the walk-in chambers of the HVAC systems using a six-stage Andersen Sampler with malt extract agar. Results showed that fungal species changed with different locations in the HVAC systems. The outdoor air intake produced the greatest filtration effect for both the counts and species of outdoor air fungi. The colony forming unit (CFU) counts and species diversity was further reduced in the air directly after the filters. The cooling coils also had a substantial filtration effect. However, in room air the CFU counts were double and the mixture of fungal species was different from the air leaving the HVAC system at the supply air outlet in most locations. Diffusion of outdoor air fungi to the indoors did not explain the changes in the mixture of airborne fungi from the outdoor air to the indoor air, and some of the fungi present in the indoor air did not appear to be transported indoors by the HVAC systems.

Infection, hyperparasitism and conidiogenesis of Mycosphaerella lateralis on Eucalyptus globulus in Western Australia

Mycosphaerella lateralis has been isolated from diseased eucalypt foliage in conjunction with the known pathogens M. cryptica and M. nubilosa. This study sought to determine whether Dissoconium dekkeri, the anamorph state of M. lateralis, infects healthy eucalypt leaves or is a hyperparasite of M. cryptica or M. nubilosa. Detached Eucalyptus globulus leaves were inoculated with conidial suspensions of M. lateralis and the progress of leaf infection studied over 6 days. Clearing and staining of the leaves showed that infection occurred via stomata after 3 days. In order to determine whether M. lateralis is a hyperparasite of M. cryptica or M. nubilosa, colonies of these species were grown adjacent to one another on either water agar, 0.2% malt-extract agar (MEA) or 2% MEA. No evidence of M. lateralis parasitising M. cryptica or M. nubilosa was found. This indicates that M. lateralis may be a foliar pathogen, rather than a hyperparasite as was previously suggested. Scanning electron microscopy was used to show that conidiogenesis of M. lateralis is both percurrent and sympodial.

Airborne Fungi in Non-Problem Buildings in a Southern-Hemisphere Mediterranean Climate: Preliminary Study of Natural and Mechanical Ventilation

There is a growing body of evidence on fungal contami nation in moisture-damaged and complaint buildings worldwide, but little is known about the occurrence and distribution of fungi in healthy non-complaint buildings in a southern-hemisphere climate. The study tested the hypothesis that fungi in healthy buildings are low in numbers and very similar to the numbers and mixtures of species in both the outdoor air and the indoor air in other parts of the world. Fungi were collected using a 6-stage Andersen sampler, and various indoor air quality (IAQ) indicators and a sick-building syndrome (SBS) questionnaire were used in parallel. The results showed that all IAQ parameters were within USA and Canadian guidelines in all the buildings. There was also a low inci dence of SBS complaints and symptoms. The total colo ny-forming unit (CFU) counts were also low, and the range of fungal species was low compared to buildings in other parts of the world. However, the mixture of fun gal genera in the indoor air was different from the out door air. There were also substantial differences be tween indoor locations. At some locations fungi includ ing Aspergillus niger, Penicillium spp. and Alternaria alternata were much higher indoors than outdoors or, as the pathogen Paecilomyces lilacinus, were absent in the outdoor air indicating indoor sources. Differentiation of fungal species was required to identify indoor fungal sources as the outdoor air was not the major source of indoor fungi. The study also demonstrated that evaluat ing the potential exposure to airborne fungi in indoor air requires differentiation to the species level as simple CFU counts could not differentiate between benign and potentially harmful fungi.

Fluorescence microscopy for the observation of nematophagous fungi inside soil

Fluorochroming of soil samples makes it possible to study soil fungi in their natural habitat. This is demonstrated with some nematophagous (predacious) fungi.

Intervention study of airborne fungal spora in homes with portable HEPA filtration units

The concentrations and composition of airborne fungal spores in homes fitted with portable HEPA filtration units were examined to provide information to evaluate the importance of varying levels of fungal spores in residential environments in Perth, Australia. A novel method for simulating activity/impaction on carpeted environments was also investigated. Reductions in fungal (35%) and particulate (38%) levels were achieved in the air filter homes. Penicillium, Cladosporium and yeasts were the most common and widespread fungi recovered indoors and outdoors. Fungal range decreased over the study period but this could be due to an overall reduced dissemination of spores (less spores in the air).

Determining the Growth and Vitality of Micro-Organisms in Carpets and Mattresses in Non-Problem Dwellings by Measuring CO2 Released during Respiration

Bedroom carpets and mattresses devoid of any reported or observed moisture damage or problems were analysed as sources of indoor fungal growth by determining the amount of CO2 released from respiration by micro-organisms living in furnishings. Dust was extracted from the carpets and mattresses using a Kirby G5 vacuum cleaner. The basal respiration rate of the dust samples without moisture added was used to estimate base respiration rate and a substrate-induced respiration rate method was used to estimate the vitality of micro-organisms in the dust and to estimate the amount of living microbial biomass. Analysis of fungal species was performed by direct sprinkling of dust samples and stamping the filter collection papers directly onto a range of nutrient agars. Fungal differentiation revealed 18 species were living in the carpets and 12 species in the mattresses. Penicillium spp., Aspergillus niger and Zygomycetes were dominant fungi. The relative abundances of fungal species in the carpets were significantly correlated to the species in the mattresses. The basal CO2 respiration rate and the living microbial biomass from all samples was the same as several soil types including sandy loam soils, Para Brown Earth, Sandy Brown Earth and Brown Podzol. The rate of respiration showed that the fungal species detected were living in the furnishings, and were highly metabolically active. This revealed that bedroom carpets and mattresses in non-problem dwellings and without moisture damage can provide a habitat with enough moisture to support fungal growth despite the lack of an obvious moisture source.

An advanced slit-type volumetric spore trap for monitoring bioaerosols; new methods for identifying fungal spores

A new slit-type volumetric spore trap (STVS) was developed to be inexpensive, light weight and reliable for sampling fungal diseases in Eucalyptus globulus plantations. It was designed with as few parts as possible to reduce the potential for mechanical failure. A simple toggle switch allowed quick changes in sampling period from 24 h to 7 days (without changing the entire sampling drum mechanism). The sampler was powered either by mains power supply or by a 12 V battery linked to a solar panel. The new STVS trap was validated alongside the industry standard Burkard spore trap. There was a highly significant correlation in spore counts (ρ = 0.992, P <0.001) between the two spore traps and no significant (P < 0.001) differences. The new STVS trap was further tested under field conditions over a 20 month period as part of a larger epidemiological study on Mycosphaerella diseases in E. globulus plantations. During the trial, the spore trap was exposed to harsh weather conditions with temperatures ranging from 2.5 to 39.9°C, wind speeds up to 38 km/h, and monthly rainfall up to 292 mm. A newly developed adhesive for spore collection allowed Mycosphaerella spores to be germinated directly on the matrix. Species were then differentiated using the new germination method.

Exposure to Airborne Mould in School Environments and Nasal Patency in Children

Mould in schools has been associated with increased upper airway obstruction in adults. In this study, we investigated the relationship between school indoor mould spore exposure and nasal patency in children. Airborne mould samples were collected in 32 classrooms from 4 primary schools during both summer and winter using a single-stage Anderson sampler. Nasal patency was measured in 275 children in summer and 200 children in winter using acoustic rhinometry. Various mould species were isolated but the most common species found inside the classrooms were Alternaria, Aspergillus niger, Cladosporium spp. and Penicillium spp. In the univariate analyses, significant negative correlations were found between exposure to various mould species, particularly Alternaria, and rhinometric measures in the children. In multivariate analyses, exposure to Alternaria was associated with both decreased mean nasal cross-sectional area (p = 0.001) and decreased nasal volume (p = 0.026). Decreased nasal patency was also associated with exposure to A. niger (p = 0.034) and Penicillium (p = 0.043) in the classrooms. The findings of this study suggest that exposure to airborne mould, particularly Alternaria, in school environments may affect the upper airways of children.