Protein Profiles of Aspergillus Species Isolated From the Tea Gardens and Factories Air in Northern Iran

Abstract

Background: Spoilage of tea (Camellia sinensis) is often accompanied by contamination and formation of mycotoxins, which are toxic secondary metabolites produced by specific tea-borne fungi. Objectives: The purposes of this study were to isolate Aspergillus flora in the air from tea gardens and factories in Gilan and Mazandaran provinces, in northern Iran, and to determine their protein patterns. Materials and Methods: Air samples were collected from 11 tea gardens and 13 tea factories between 2006 and 2008, and cultured in specific fungal media. Mycelial mats and spores of the Aspergillus species were disrupted in liquid nitrogen containing glass beads. The crude extracts were separated from other cell components by centrifugation and sterilized using a filter. The extracts obtained were analysed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) to separate the fungal antigenic proteins. Results: A total of 4 157 fungal colonies were observed in the tea gardens air and 3 950 colonies in the tea factories air. The most dominant and frequently occurring Aspergillus flora were; A. niveus (14.4%) and A. unguis (12.6%) in the gardens, and A. melleus (14.3%) and A. niger (12.3%) in the factories. The highest number of Aspergillus species collected from the tea gardens and factories were associated with the regions of Lahijan (23.9%) and Rasht (18.8%), respectively. The results from the SDS-PAGE method indicated that various Aspergillus species had 55 protein bands, which ranged from 5 to 120 kDa. Among these species, A. foetidus had the maximum number of protein bands (22 bands) ranging from 14.4 to 120 kDa, while A. unguis contained the minimum protein bands (5 bands) ranging from 30 to 120 kDa. Conclusions: The results revealed the presence of a variety of Aspergillus species in tea gardens and factories air, and the presence of a large number of Aspergillus species based upon the protein banding patterns obtained with SDS-PAGE analysis.