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Department of Microbiology, Faculty of Sciences and Informatics, University of Szeged, H6726, Szeged, Közép fasor 52,
Hungary
*Corresponding author: email: galgoczi@gmail.com, Phone: +36 62 544 005, Fax: +36 62 544 823
The incidence of fungal infections has increased continuously during recent years in consequence of the increasing number
of imunocompromised hosts and the occurring of antibiotic resistant strains. Another important aspect is that many
filamentous fungi are destructive pathogens of plants and are thus responsible for enormous crop losses worldwide.
Therefore, there is a substantial demand for new compounds with extensive antifungal activity. The proteins with similar
structure like defensins secreted by filamentous fungi are interesting from this respect. These proteins secreted by
taxonomical distinct species have different mode of action and species specificity, nevertheless, their structure is very
similar. They are promising compounds in medical and agricultural fields; and their features (high stability and efficacy,
safety application, limited toxicity and low costs of production) could make them suitable for use in practicable respects in
the future.
$ filamentous fungi; defensinlike antifungal proteins, susceptibility, mode of the action, protein expression
% &
Defensins are a family of evolutionary related antimicrobial peptides [1]. They are part of the second defence system,
innate immunity that was discovered in the early 1980s in the higher organisms. These small molecular weight cationic
peptides have a characteristic βsheet rich fold and a framework of disulfidelinked cysteines [13]. They have a broad
antimicrobial spectrum and different mode of action [1, 2, 4, 5]. Similar proteins are widely distributed in the nature;
they are not limited to higher organisms, their presence is confirmed in insects, plants and fungi [2, 5, 6]. Their
antimicrobial effects are exerted on three major targets in the sensitive organisms: cell wall, cell membrane and
intracellular organelles [2, 4].
The features of extracellular, defensinlike antifungal proteins secreted by filamentous fungi are a low molecular
mass (5.86.6 kDa), a basic character, and the presence of 610 cysteine residues and several disulfide bonds. Proteins
with such properties with antifungal activity have been isolated and investigated from 4 ascomycetous fungal species
( , , and ). Furthermore,
investigation of genomic databases has been revealed a putative protein with high homology to them in
, and [7, 8]. A highly homologues putative protein is deduced
in CBS 518.88 strain with 7 differences in amino acid sequence of the mature protein compared to
antifungal protein (ANAFP) [9] (Fig. 1.). Only one similar protein with an antibacterial activity has been described in
the literature so far in a zygomycetous fungus. The var. antibiotic peptide (ABP)
encoded by two genes with one amino acid difference in the signal sequences ( and ) has an antibacterial
effect only against some Grampositive bacteria [9].
Their safety, sustainability, high efficacy, limited toxicity and low costs of production could make them favourable
compounds in medicine and agriculture in the near future [7, 8, 10]. antifungal protein (PAF) and
antifungal protein (AFP) are the most intensively studied fungusderived antifungal proteins.
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Current Research, Technology and Education Topics in Applied Microbiology and Microbial Biotechnology
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