Partial purification and characterization of mold antigens commonly found in foods

Abstract

Rapid methods are needed for detection of molds in foods; therefore, an enzyme-linked immunosorbent assay was developed. The extracellular and mycelial antigens for Mucor, Aspergillus, Cladosporium, and Geotrichum species were partially purified and characterized. The molecular masses of the mycelial and extracellular antigens, as determined by size exclusion chromatography, ranged from 4.5 x 105 to 6.7 x 105 Da. There was only one main antigenic peak separated by Sepharose CL-4B and concanavalin A-Sepharose columns for Mucor, Cladosporium, and Geotrichum mycelial and extracellular antigens, but there were two for Aspergilus mycelial antigens and three for Aspergillus extracellular antigens. These antigens contained 10 to 50%o protein which was part of the active site since protease digestion significantly decreased antigenic activity. Neutral sugars, ranging from 13 to 75%, made up the rest of the active site, and <1% phosphate was detected in mycelial antigens. Geotrichum, Cladosporium, and Aspergillus antigens contained mainly glucose, galactose, and mannose. Mucor antigens contained these sugars plus fucose. The percentage of sugars differed between the mycelia and extracellular antigens. Enzymatic digestion and competitive inhibition tests using different sugar derivatives showed that galactosyl residues with 1 linkages were immunodominant for Aspergilus, Geotrichum, and Cladosporium antigens and mannosyl residues with a linkages were immunodominant for Mucor antigens.

Diagnostic tests and their application in the management of soil- and water-borne oomycete pathogen species

“…Enzymatic digestion and competitive inhibition tests demonstrate that galactosyl residues with β‐linkages are immunodominant for Aspergillus , Geotrichum and Cladosporium antigens. Mannosyl residues with α‐linkages provide immunodominance for Mucor antigens (Tsai & Cousin, ). The structure and complexity of these pathogens can thus lead to the production of antibodies that are able to bind selectively to both related and non‐related species (Notermans & Soentoro, ; Mohan 1989 a , b ; Priestley & Dewey, ; Viudes et al , ; Da Silva Bahia et al , ).…”