Purification and characterization of a surface lectin from the nematode-trapping fungus Arthrobotrys oligospora

Abstract

Several studies have indicated that the capture of nematodes by the nematophagous fungus Arthrobotrys oligospora is mediated by a lectin on the fungal surface. One of the major surface proteins of this fungus showed haemagglutinating activity and was isolated by affinity chromatography using a mucin Sepharose column. Biochemical analysis showed that the protein was a dimeric glycoprotein with a molecular mass of 36 kDa and an isoelectric point of pH 6.5, and contained no sulphur amino acids. The protein was N-terminally blocked; four internal peptides were sequenced, and showed no significant similarity to sequences in the Swiss-Prot or PIR databases. The haemagglutinating activity of the isolated protein was not inhibited by any of the mono-or disaccharides tested, but it was inhibited by the glycoproteins fetuin and much The haemagglutinating activity changed after incubating the protein in buffers of different pH, with maximal activity at pH 11.0 and no activity at pH 2.8. The lectin was tested for different enzymic activities but none were detected. Analysis of the haemagglutinating activity in various cell fractions indicated that the protein was associated with extracellular polymer layers and with the cell wall of the fungus. About the same amount of the haemagglutinating protein was recovered from samples of vegetative mycelium and of mycelium containing nematode-trapping cells.

Optimization of culture conditions and characterization of a new lectin from Aspergillus niger

“…Although many fungal lectins have been reported, most of them are from fruiting bodies of mushrooms [8]. Mycelial lectins have been reported from Rhizopus stolonifer [9] and Arthrobotrys oligospora [10]. There are also reports on extracellular lectins from Lentinus edodes [11] and Sclerotium rolfsii [3].…”

Inhibitory action of a new lectin from Xerocomus chrysenteron on cell-substrate adhesion

“…The lectin from the common edible mushroom Agaricus bisporus (ABL) has been shown to have a reversible antiproliferative effect without inducing any cytotoxicity in a wide range of epithelial cell types [4]. The lectin from the mushroom Xerocomus chrysenteron (XCL) belongs to the same group of lectins firstly described for ABL and AOL (Arthrobotris oligospora lectin) for sequence homology and sugar specificity [5]: XCL and ABL, sharing 55% sequence identity, are both specific for N-acetyl galactosamine and galactose. Consequently, the antiproliferative activity of XCL was studied using different cell lines in order to assess the mechanism by which this lectin could potentially elicit its biological effects.…”

New lectins from aspergilli and their carbohydrate specificity

“…The minimum concentration required for complete inhibition was 0.0039 mg/mL for bovine submaxillary mucin and 0.0078 mg/mL for porcine stomach mucin. Mucin specific lectins have been reported from Arthrobotrys oligospora (Rosen et al 1992), Aspergillus sp. (Singh et al 2010b) and Penicillium sp.…”