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], the analysis of expressed sequence tag (EST) libraries derived from homogeneous single-cell populations of aerial conidia, in vitro blastospores and submerged conidia of the entomopathogenic fungus Beauveria (Cordyceps) bassiana has been reported.Here an extended EST analysis is presented of complex cell mixtures derived from fungal cells sporulating on chitin or grown under culture conditions inducing the production of the B. bassiana secondary metabolite, oosporein. Fungal material used for the construction of the libraries included germinating conidia and blastospores, mycelia, as well as cells in various developmental stages. Approximately 2500 59 end sequences were determined from random sequencing of clones from each library, and were clustered into 277 contigs with 1069 singlets, and 306 contigs with 1064 singlets, for the chitin and oosporein libraries, respectively. Almost half (45-50 %) of the sequences in each library displayed either no significant similarity (e value >10 "4 ) or similarity to hypothetical proteins found in the NCBI database. Approximately 20-25 % of the sequences in each library could be annotated by gene ontology terms. A comparative analysis between the two libraries, as well as the libraries in the accompanying paper, is presented. A set of 4360 clustered and unique sequences was characterized. The data are indicative of a highly plastic gene expression repertoire being available to B. bassiana for growth during different environmental and developmental conditions, and provides a dataset for gene discovery and genome annotation.

Hydrophobins are small amphipathic proteins that function in a broad range of growth and developmental processes in fungi. They are involved in the formation of aerial structures, the attachment of fungal cells to surfaces, and act in signalling in response to surface cues and pathogenesis. Beauveria bassiana is an important entomopathogenic fungus used as an arthropod biological control agent. To examine the feasibility of using phage display technology to clone cDNAs encoding hydrophobins, biopanning experiments were performed using a variety of affinity resins, including N,N9-diacetylchitobiose-, fucose-, lactose-, maltose-and melibiose-coupled agarose beads. After five rounds of iterative biopanning, cDNAs corresponding to two B. bassiana (class I) hydrophobins were selectively enriched using melibiose-or lactose-coupled agarose beads. Expression analysis revealed that the hyd1 gene was expressed in all samples tested, including aerial conidia, in vitro blastospores, submerged conidia, and cells sporulating on chitin and insect cuticle, with hyd1 expression peaking in growing mycelia. In contrast, the hyd2 gene was not appreciably expressed in any of the single-cell types (aerial conidia, blastospores and submerged conidia), but was constitutively expressed in growing mycelia and when cells were sporulating on chitin and insect cuticle. MS fingerprinting of an~10 kDa protein found in boiling SDS-insoluble, trifluoroacetic acid-soluble extracts from aerial conidia identified the major component of the B. bassiana rodlet layer to be the hyd2 gene product. These results reveal the differential regulation of the isolated hydrophobins and indicate that phage display represents a novel approach to cDNA cloning of hydrophobins.

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We report a new approach for the detection of ochratoxin A (OTA) by introducing surface-enhanced Raman scattering (SERS). This method is based on different adsorption propensities of Raman reporter Cy5-tagged OTA aptamer. The OTA aptamer could be easily adsorbed onto the surface of silver nanoparticles (AgNPs) to give fairly strong SERS signals, whereas such bindings would be hampered in the presence of OTA. On the addition of OTA in the concentration range of 0.1-10 nM, the SERS signals appeared to decrease by 40%, since OTA's aptamer could not adsorb onto the surface of AgNPs due to binding with OTA. We verified our results against a control experiment with warfarin, which did not affect the SERS signals. A nanomolar detection limit of OTA was achieved using the current SERS-based method.