Determination of antimicrobial spectrum of K9 type yeast killer toxin and its cell killing activity

Download

index.pdf

Date

2006

Author

Yener, Burcu

Metadata

Show full item record

Item Usage Stats

306
views

108
downloads

Some yeast strains secrete extracellular polypeptide toxins known to have potential growth inhibitory activity on other sensitive yeast genera but are immune to their own toxins. These yeast strains are termed as killer yeasts and their toxins are designated as killer proteins or killer toxins. Killer phenotypes are classified into 11 typical types (K1-K11). The toxic actions of yeast killer proteins on sensitive cells show differences and one of the most important toxic actions involves the selective functional damage by hydrolyzing major cell wall components. Because mammalian cells lack a cell wall, novel highly selective antifungals tend to be harmless to people by targeting important cell wall components specific to fungi. We have previously characterized the K9 type yeast killer protein isolated from Hansenula mrakii. This protein is stable at pH and temperature values appropriate for its medical usage. Antifungal activity of this protein was tested against 23 human pathogenic yeast and 9 dermathophyte strains. Pathogenic yeast strains found to be susceptible and both the MIC and MFC values ranged from 0.25 to 8 g/ml except C. parapsilosis and C guilliermondii isolates. 9 dermatophyte strains were not susceptible to this protein and MICs were >64 g/ml. According to the cell killing analysis toxin activity starts within the first 4 hours and complete cell death was observed for the 4, 8 and 16 times the MIC concentrations at 24 hour. The results obtained from this study might make the potential use of this protein possible as a selective antimycotic agent.

Subject Keywords

General Biology .

URI

http://etd.lib.metu.edu.tr/upload/12607350/index.pdf
https://hdl.handle.net/11511/16259

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Antimicrobial spectrum determination of the K5 type yeast killer protein on bacteria causing skin infections and its cell killing activity Gönen, Tuğçe; İzgü, Kadri Fatih; Department of Biology (2006) Some yeast strains secrete extracellular polypeptide toxins known to have potential growth inhibitory activity on sensitive yeast cells. These yeast strains are known as killer yeasts and their toxins are named as killer toxins or killer proteins. Yeast killer proteins are found inhibitory to Gram-positive bacteria in several studies which were based on microbial interactions of the producer strains tested with sensitive strains. K5 type yeast killer protein produced by Pichia anomala NCYC 434 was previousl...
Mechanism of inhibition of cytochrome p4501a1 associated 7-ethoxyresorufin o-deethylase (erod) activity and glutathione s-transferase (gst) activities in fish liver by phenolic compounds/flavonoids Yılmaz, Duygu; Arınç, Emel; Department of Biology (2010) Flavonoids, present in fruits, vegetables and beverages derived from plants, have been described as health-promoting, disease-preventing dietary supplements, and have activity as cancer preventive agents. The cancer protective effects of flavonoids have been attributed to a wide variety of mechanisms, including modulating enzyme activities resulting in the decreased carcinogenicity of xenobiotics. Cytochrome P4501A1 (CYP1A1) is a Phase I enzyme which is known to be involved in the activation of procarcinoge...
Investigating the anticarcinogenic role of salix aegyptiaca l. in colorectal carcinoma Enayat, Shabnam; Banerjee, Sreeparna; Department of Biology (2009) In this study, extracts from bark, leaves and catkins of Salix aegyptiaca L. were investigated for their antioxidant content by 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) free radical quenching assay, total phenolic and total flavonoid assays. The highest antioxidant activity (19 ug/ml IC50 for inhibition of DPPH radical activity), total phenolic content (212 mg gallic acid equivalents/g of dried extract) and total flavonoid (479 mg catechin equivalents/g of dried extract) was observed in the ethanolic ex...
The effect of cysteine-43 mutation on thermostability and kinetic properties of citrate synthase from Thermoplasma acidophilum Kocabıyık, Semra; Russel, RJM; Danson, MJ; Hough, DW (Elsevier BV, 1996-07-05) In this study, we have substituted serine-43 by cysteine in the recombinant citrate synthase from a moderately thermophilic Archaeon Thermoplasma acidophilum, for site-specific attachment of labels and have investigated the effects of this mutation on the biochemical properties and thermal stability of the enzyme. Both wild-type and the mutant enzymes were purified to homogenity using affinity chromatography on Matrex Gel Red A. The mutant Thermoplasma citrate synthase is very similar to wild-type citrate s...
Preliminary approch for the determination of fish exuded kairomone using fourier transform infrared spectroscopy Kepenek, Ayşe Özge; Severcan, Feride; Department of Biology (2005) Chemical communication in aquatic organisms has been topic of a large number of studies focusing interactions between organisms via info chemicals. Diel Vertical Migration (DVM) is commonly observed among zooplankton and consists of a single daily ascent with minimum depth reached between sunset and sunrise and a descent with maximum depth attained during the day. DVM was absent or reduced when predators were absent and well developed in their presence. Species of the Daphnia are one of the well investigate...

Citation Formats

B. Yener, “Determination of antimicrobial spectrum of K9 type yeast killer toxin and its cell killing activity,” M.S. - Master of Science, Middle East Technical University, 2006.