title: Purification of Candida guilliermondii and Pichia ohmeri killer toxin as an active agent against Penicillium expansum.
abstract: An antifungal assay with cell-free culture supernatant of Pichia ohmeri 158 and Candida guilliermondii P3 was tested against Penicillium expansum strain #2 at 25 degrees C by measuring hyphal length and percentage conidia germination. C. guilliermondii was more effective against P. expansum conidia germination (58.15% inhibition), while P. ohmeri showed higher inhibition of mycelial growth (66.17%), indicating a probable mechanism associated with killer activity. This killer toxin (molecular mass <3 kDa) was partially purified by normal phase HPLC, using TSKgel Amide-80 analytical and preparative columns. Compared with crude extract, the killer toxin eluted from the post analytical column significantly inhibited P. expansum:% inhibition rose from 42.16 to 90.93% (C. guilliermondii) and 39.32 to 91.12% (P. ohmeri) (p < 0.05). The one-step purification process was adequate in isolating killer toxin from culture supernatant and also increased anti-Penicillium activity.
authors.affiliation: Department of Food Technology, State University of Londrina, Brazil. coelhoar@hotmail.com
authors.forename: Alexandre Rodrigo
authors.initials: AR
authors.lastname: Coelho
authors.forename: Masahico
authors.initials: M
authors.lastname: Tachi
authors.forename: Fernando Carlos
authors.initials: FC
authors.lastname: Pagnocca
authors.forename: Gisele Maria Andrade
authors.initials: GM
authors.lastname: Nobrega
authors.forename: Fernando Leite
authors.initials: FL
authors.lastname: Hoffmann
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Harada
authors.forename: Elisa Yoko
authors.initials: EY
authors.lastname: Hirooka
mesh_terms: D000898:Antibiosis; D002175:Candida / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005516:Food Microbiology; D055646:Killer Factors, Yeast / Q000302:isolation & purification / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D010407:Penicillium / Q000187:drug effects* / Q000254:growth & development; D010572:Pest Control, Biological / Q000379:methods; D010843:Pichia / Q000737:chemistry
chemical_list: D055646:Killer Factors, Yeast; C087906:killer toxin, Pichia