Production of a Chaetomium globosum enolase monoclonal antibody

Chaetomium globosum is a hydrophilic fungal species and a contaminant of water-damaged building materials in North America. Methods to detect Chaetomium species include subjective identification of ascospores, viable culture, or molecular-based detection methods. In this study, we describe the production and initial characterization of a monoclonal antibody (MAb) for C. globosum enolase. MAb 1C7, a murine IgG1 isotype MAb, was produced and reacted with recombinant C. globosum enolase (rCgEno) in an enzyme-linked immunosorbent assay and with a putative C. globosum enolase in a Western blot. Epitope mapping showed MAb 1C7 specific reactivity to an enolase decapeptide, LTYEELANLY, that is highly conserved within the fungal class Sordariomycetes. Cross-reactivity studies showed MAb 1C7 reactivity to C. atrobrunneum but not C. indicum. MAb 1C7 did not react with enolase from Aspergillus fumigatus, which is divergent in only two amino acids within this epitope. The results of this study suggest potential utility of MAb 1C7 in Western blot applications for the detection of Chaetomium and other Sordariomycetes species.

Quantification of C. globosum spores in house dust samples

Chaetomium globosum is one of the most common fungi that grows in damp buildings and occurs in agricultural and forestry workplaces. Using sera from atopic patients, we characterized and purified an extracellular chitosanase (Chg47) from C. globosum that is antigenic to humans. The study reports the production of monoclonal antibodies to the protein. Three capture ELISAs were developed for Chg47 for detection of spores and spore and mycelial fragments in dust samples using different mono- and polyclonal antibody combinations. One method is based on an enhanced biotinylated polyclonal antibody as the secondary antibody and coating anti-IgM to capture one of two clones of IgM monoclonal antibodies as the capture antibody. The other method makes use of an enhanced rabbit polyclonal antibody as both the primary and capture antibody. The detection limit of the double PAb method for the Chg47 antigen was 7.6 pg/ml. When the anti-IgM+10B3 clone was used, the detection limit was 61 pg/ml and for anti-IgM+5F12, 122 pg/ml. The detection limit of double PAb method is comparable to methods for the allergen and spores of Aspergillus versicolor in house dust and is more sensitive than other immunoassays for allergens in house including for Stachybotrys chartarum, Aspergillus fumigatus and Alternaria alternata. All three methods had limited cross-reactivity to fungi common in house dust representing a diverse array of taxa.

Infection of barley roots by Chaetomium globosum: evidence for a protective role of the exodermis

Plant pathogenesis by fungi is known to be dependent on the host genotype, the virulence of the pathogen and certain environmental conditions influencing fungal establishment. Previously, it has been shown that Chaetomium globosum, a fungus well-characterized for its biocontrol potential, causes necrosis on barley roots grown in Murashige and Skoog (MS)-agar. Using MS-agar and aeroponic culture as axenic plant growth systems, C. globosum pathogenesis was analyzed with serological and histological methods. Irrespective of the growth system, C. globosum infected the root epidermis. Roots grown in MS-agar were extensively colonized intercellularly and intracellularly up to the inner cortex and the tissue underwent necrosis. In contrast, roots grown in aeroponic culture were not colonized beyond the epidermis and the roots appeared healthy. Histochemical analyses revealed that hypodermal suberization stopped fungal invasion. In root tips known to lack suberization, epidermal papilla formation reduced overall infection frequency. The results indicate that specific environmental conditions are important for infection and disease expression in barley roots. Infection is restricted by two spatial and temporal distinct defence mechanisms: (1) papillae in root tips retarding fungal invasion; and (2) suberization of hypodermal cells blocking fungal radial growth.

A study of the aeromycoflora of Cádiz: relationship to anthropogenic activity

We describe a quantitative and qualitative study of the fungal spores found in the air of Cádiz during 1989 using a Cour-type trap. The results of this study can be extrapolated to other coastal cities of southern Europe with a Mediterranean climate. The spores identified have been classified into 25 taxonomic categories. The most abundant were Cladosporium, Chaetomium and Ustilago, and the most frequent, in addition to those mentioned, were Alternaria, Ascophyta and Venturia. The great abundance of Cladosporium is in accordance with the coastal situation of the city. Cladosporium, Alternaria, Curvularia and Stemphylium reached maximum concentrations jointly in October, 1989. They showed mutual cross-reactions. Ustilago and Nigrospora appeared during the period of cereal harvesting and storage.