Previous studies showed significant allergenic activity for myxomycete spores; however, little is known about their atmospheric concentrations. Fruiting bodies of these fungal-like organisms are common in nature and have also been found on indoor substrates. Investigations of the airborne concentrations have been hindered by spore identification problems. The goal of this project was to investigate morphology and determine atmospheric concentrations of these spores in the Tulsa area.
Both light microscopy (LM) and scanning electron microscopy (SEM) were utilized to determine spore size, shape, and ornamentation from field collected specimens. For LM, spores were mounted in lactophenol with polyvinyl alcohol and examined at 1000x. For SEM, spores were dehydrated, air dried following hexamethyldisilazane treatment, mounted on stubs, and sputter coated. Air samples from 2001 to 2003 were collected with a Burkard Spore Trap using standard methods and examined at 1000x for spore identification and enumeration.
LM revealed that spore pigmentation ranges from colorless to brownish-gray. Spores are typically thin-walled, globose, and 5-13µm in diameter. Ornamentation varies from granular to reticulate to echinate but is not always visible with LM. Myxomycete spores were identified in air samples on 64% of the days. Concentrations were highest in June, July, and September with the peak of 520 spores/m³ on 9 Sep 2003.
Myxomycete spores are present in the air for a significant portion of the year in Tulsa, Oklahoma. More information about atmospheric concentrations from other areas is needed to determine the clinical significance of these aeroallergens.