title: Comparison of killer toxin-producing and non-producing strains of Filobasidium capsuligenum: proposal for two varieties.
abstract: The basidiomycetous yeast, Filobasidium capsuligenum, produces killer toxin against the opportunistic pathogen Cryptococcus neoformans. Not every strain isolated so far is able to produce the anti cryptococcal toxin. The aim of the present work was to study the relationship between the toxins and the toxin-producing and non-producing isolates. The toxin was coded on chromosomal DNA in each producing strain as molecular analysis revealed. In addition, both the killing spectra and biochemical properties of the toxins proved to be identical, thus intraspecific variation in the toxin was not found. For molecular typing of the isolates, the D1/D2 region of 26S rDNA, partial sequences of internal transcribed spacer (ITS) regions, PCR fingerprinting RAPD and mtDNA-RFLP patterns were examinated. Phylogenetic analyses based on the different approaches showed that strains with the ability of killer-toxin production and those without it differ significantly and cluster into two distinct groups. The differences between the two groups and the similarity within them suggest the authority to separate the species into varieties.
authors.affiliation: Department of Microbiology University of Szeged, Szeged, Hungary. andrea.keszthelyi@gmail.com
authors.forename: Andrea
authors.initials: A
authors.lastname: Keszthelyi
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Hamari
authors.forename: Ilona
authors.initials: I
authors.lastname: Pfeiffer
authors.forename: Csaba
authors.initials: C
authors.lastname: Vágvölgyi
authors.forename: Judit
authors.initials: J
authors.lastname: Kucsera
mesh_terms: D001487:Basidiomycota / Q000145:classification / Q000235:genetics / Q000502:physiology*; D015825:Chromosomes, Fungal; D016000:Cluster Analysis; D003455:Cryptococcus neoformans / Q000187:drug effects; D016172:DNA Fingerprinting; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005656:Fungal Proteins / Q000378:metabolism*; D005800:Genes, Fungal; D005838:Genotype; D055646:Killer Factors, Yeast; D008969:Molecular Sequence Data; D016533:Mycological Typing Techniques; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D011506:Proteins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity; D012335:RNA, Ribosomal / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D005656:Fungal Proteins; D055646:Killer Factors, Yeast; D011506:Proteins; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S