1. L'Ascomicete Ceratocystis fimbriata è responsabile della malattia del cancro colorato che colpisce il Platanus acerifolia nel sud Europa. Dal filtrato colturale del ceppo Cf AF 100, isolato da platani infettati naturalmente, è stata isolata, purificata e sequenziata una proteina di 12,4 KDa che abbiamo chiamato cerato-platanina (CP). La proteina pura induce la necrosi, se infiltrata in foglie di tabacco, e causa l'appassimento di recisi di germogli di platano.
Questa proteina è altamente omologa a due proteine prodotte da Ascomiceti: la proteina codificata dal gene snodprot1 di Phaeosphaeria nodorum (agente causale delle macchie scure del grano) e l'allergene rAsp f13 da Aspergillus fumigatus. Alcune caratteristiche strutturali della CP avvicinano questa proteina alle idrofobine, una famiglia di proteine con bassa omologia di sequenza ma caratterizzate tutte dal basso PM (<150 AA), da 8 Cys, dalla sequenza consenso CCN e da una moderata idrofobicità.
2. Le allergie causate dalle punture degli insetti appartenenti alla famiglia dei Vespidae (genere Polistes, Vespa, e Vespula) sono dovute ad una interazione fra le IgE con gli allergeni del veleno. Lo studio di questi allergeni ha una notevole importanza per la immunoterapia di soggetti allergici. Abbiamo isolato e caratterizzato i maggiori allergeni contenuti nel veleno di Polistes gallicus: antigene 5 (Ag5), fosfolipasi (PL), Ialuronidasi (HL), serina-proteasi (PR) e una proteina ignota (RP3). Dell'Ag5 è stata determinata la sequenza aminoacidica completa. Questi studi sul veleno di specie europee di Polistes dovrebbero rappresentare una base per il miglioramento dell'immunoterapia di soggetti europei che sono scarsamente immunizzati dai veleni commerciali attualmente provenienti dagli USA.
 Stucture and function of proteins from phytopathogen fungi
Cerato-platanin (CP) is a recently described protein of about 12.4 kDa released in culture by Ceratocystis fimbriata f.sp. platani (Cfp), the causal agent of the plane canker stain disease. CP has been determined on the cell wall surfaces of aerial mycelium of Cfp more abundantly than that submerged, and is secreted in the liquid medium just after the first days of culture. CP seems to share more than a significant role in the host plane-pathogen interaction. It rapidly causes plane cuttings to wilt, and few nanomoles of protein elicits the synthesis of umbelliferone-like phytoalexins by plane leaves; also CP seems to be involved in the adhesion of Cfp conidia to wood chips during pruning. Moreover, CP induces necrosis of tobacco leaf mesophyllum cells and synthesis of glyocellin phytoalexin in treated soya cotyledons.
This protein was purified from culture filtrate and successively the complete primary structure was determined . The CP is highly homologous with two proteins produced by other Ascomycete fungi. One is produced during infection of wheat leaves and codified by the snodprot1 gene of Phaeosphaeria nodorum, whereas the other is the rAsp f13 allergen from Aspergillus fumigatus. Some features of cerato-platanin link this protein to hydrophobins (small hydrophobic proteins containing disulfide bridges and the sequence consensus CCN).
Studies on the immunoreactivity of the major allergens purified from polistes gallicus venom
Sting allergies caused by insects the family Vespidae (genera Polistes, Vespa, and Vespula) result from the interaction of cell-bound specific IgEs with allergens of the venom. Actually the conventional therapy consists in a desensitisation by specific immunotherapy (SIT) using the pure venom from American species of Polistes. Unfortunately, European patients are poorly desensitised by American venoms, and many studies are carried out on the allergenic components of the Polistes venoms in order to detect the molecular basis of their different allergenic activity. The major antigenic components isolated from Polistes venoms are four proteins: Antigen 5 (Ag5), phospholipase (PL), hyaluronidase (HL), and a serine protease (PR). The Ag5 was purified and sequenced from P. annularis, P. exclamans, P. fuscatus and P. dominulus. The primary structure of PL from P. annularis is also available, but no PR sequences are known. In our laboratory, we have purified and characterised the Ag5, PL, PR, HL and a new antigenic protein (called RP3) from P. gallicus (an European species); the Ag5 sequence has been completely determined. The molecular characterisation of P. gallicus, and other European Polistes venoms could help us to improve the immunotherapy (SIT) method.
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