The polyene macrolide antibiotic natamycin (Antibiotic A-5283) is commonly used to retard the growth of surface molds on various cheese varieties. Natamycin is commonly applied to the surface of cheese by dipping or spraying, using an aqueous dispersion containing 200 to 300 ppm of the additive. The large molecular weight of natamycin, 666 g/mol, and conjugated double bond structure causes it to be extremely insoluble in water and most food grade solvents. The inability to apply natamycin in true solution creates void non-treated areas on the food surface. These non-treated areas promote the growth of fungal organisms. A water soluble N-alkyl semisynthetic derivative of natamycin was synthesized by the Michael addition reaction of the parent with a N-substituted malemide. A comparative study investigating the effectiveness of the semisynthetic derivative of natamycin and the parent antibiotic in suppressing mold growth on one month aged shredded Cheddar cheese modified atmosphere packaged (MAP) was performed. A 20 ppm natamycin treatment effectively suppressed visible mold growth (<104 CFU/g) in MAP samples for up to 30 days after opening. The 20 ppm semisynthetic derivative performed similarly to the 10 ppm natamycin treatment in retarding mold growth. Visible mold growth did not occur for these treatments in MAP samples until 20 days after opening. Analysis of storage conditions revealed that an outgrowth of mold in shredded cheese occurred in MAP packages stored longer than 15 days. This bloom in mold growth was attributed to the degradation of natamycin and the semisynthetic derivative throughout storage. The stability and degradation of natamycin and the derivative were monitored throughout the study. Antibiotic concentration on the cheese surface was quantified by molecular absorption spectrometry. Results from this study showed, heavily contaminated samples caused the rate and loss of natamycin and the derivative to increase. Antibiotic concentration decreased at a similar rate in MAP and open package conditions. Natamycin and derivative were found to have similar degradation properties. / Master of Science

The optimalization way of hormonal induction ovulation females barbels (Barbus barbus) hunted from river is the aim of work with the help of hormonal preparate on the base functional of the analogue GnRH.

Bakgrund: Svampinfektion i underlivet drabbar oftast kvinnor vid fertila ålder, ungefär 75% av kvinnor får det någon gång i livet. Svampinfektioner behandlas med antimykotika framförallt receptfria läkemedel, problemet med frekvent användning av receptfria läkemedel är att svampen kommer tillbaka inom kort igen eller förorsakar att det blir svårare att bli av med svampen. Syftet med studien är att sammanfatta och värdera kvalitén av de tillgängliga randomiserade kontrollerade studier samt avgöra om oral eller lokal antimykotika behandling är effektivast vid genital candidainfektion? Metod: Databassökning av studier genomfördes i både Pubmed och Cochrane Library för att söka efter systematiska reviews, reviews och RCT studier. RCT studierna värderades med CONSORTstatement och bedömdes antingen med låg, medel eller hög kvalité. Studierna sammanställdes i tabeller för att jämföra skillnaden i effektiviteten mellan oral eller lokal behandling. Resultat: Sökningen identifierade 190 studier varav fyra betraktades som relevanta. Bedömningen presenterade en av studierna som hög kvalité och resten medelkvalité. Tre av fyra studier visade ingen skillnad på effektiviteten mellan oral och lokal antimykotika behandling, medan endast en studie visade signifikant skillnad som gynnade den orala behandlingen. Slutsats: Generellt erhöll studier som var inkluderade i denna litteraturstudie bra kvalité vid bedömningen. Dessutom visade majoriteten av undersökningarna från både gamla och nya studier att det inte finns någon skillnad i effektivitet hos orala och intravaginala antimykotika behandling. / Background: Vaginal yeast infections usually affect women at fertile age, about 75% of women get it at some point in their lives. Vaginal yeast infections are treated with antimycotics, primarily with non-prescription drugs, the issue with frequent use of non-prescription drugs is that the fungus comes back shortly again, or it becomes difficult to get rid of. The aim of the study is to summarize and evaluate the quality of available randomized controlled trials and determine if oral or local antimycotics treatment is effective in genital candidiasis? Method: Database search of studies was conducted in both PubMed and Cochrane Library to search for systematic reviews, reviews, and RCT studies. RCT studies were evaluated with CONSORT statement and assessed with low, medium or high quality. The studies were compiled in tables to compare the difference in efficacy between oral or local treatment. Result: The search identified 190 studies, of which four were considered relevant. The assessment presented one of the studies as high quality and the rest medium quality. Three out of four studies showed no difference in efficacy between oral and local antifungal therapy, while only one study showed significant difference, which favored the oral treatment. Conclusion: Overall, studies that were included in this literature study were of good quality when assessing. Moreover, most of the researches from both old and new studies showed that there is no difference in the efficacy of oral and intravaginal antifungal therapy.

Natamycin is an antimycotic with very low water solubility and extremely high photosensitivity, which is used to extend the shelf life of shredded cheese products. The objectives of this research are: (a) to find a new delivery system for natamycin, which increases its aqueous solubility and (b) to increase the chemical stability of natamycin so that it has a prolonged antifungal effect on the surface of the shredded cheese. Molecular inclusion complexes of natamycin were formed with β-, hydroxypropyl β-, and γ- cyclodextrins (CDs) which allowed large increases in aqueous solubility without the use of organic co-solvents or surfactants. The water solubility of natamycin was increased 16-fold, 73- fold, and 152-fold with β-CD, γ-CD, and hydroxypropyl β-CD, respectively. The natamycin:CD inclusion complexes resulted in nearly equivalent in vitro antifungal activity as natamycin in its free state. Nuclear magnetic resonance (NMR) was utilized to prove the formation of true inclusion complexes. 1H NMR shift titrations of N-(3 -N-dimethylaminosuccimido) natamycin with β- and γ-CDs enabled determination of the stoichiometry of both complexes as 1:1. Aqueous solutions of natamycin (20 mg/L) were found by quantitative HPLC to be completely degraded after 24 hours of exposure to 1000 lux fluorescent lighting at 4 °C. After 14 days of storage in darkness at 4 °C, 92.2% of natamycin remained in active form. Aqueous solutions of natamycin:β-CD complex and natamycin:γ-CD complex were significantly more stable (p < 0.05) than natamycin in its free state when stored in darkness at 4 °C. Clear poly(ethylene terephthalate) packaging with an ultraviolet light absorber allowed 85.0% natamycin to remain after 14 days of storage under 1000 lux fluorescent lighting at 4 °C. Such dramatic increases in water solubility and light stability will enable natamycin to function as a more effective antimycotic in the food industry. / Master of Science

Natamycin is an antimycotic compound that is widely used in the cheese industry to increase the shelf life of cheeses, especially shredded cheeses, by inhibiting the growth of molds. Natamycin is applied to the surface of cheese as an aqueous suspension or as a powder. However, natamycin is not readily water soluble making it harder to distribute evenly over shredded cheese Natamycin is degraded by ultraviolet (UV) light at wavelengths of 350 nm and below. Typical packaging applications do not provide adequate UV protection causing natamycin to degrade. This work was undertaken to determine the efficacy of UV absorber film to prevent UV light degradation of natamycin on the surface of shredded cheese. Current accepted methods to determine concentration of natamycin were evaluated for appropriateness in natamycin degradation studIes. The use of cyclodextrins to increase water solubility was tested to see if a uniform distribution of natamycin over the shredded cheese could be done effectively. Furthermore, a known application of mold was performed to see how well natamycin and each of its applications could prevent visible mold growth from occurring. The International Dairy Federation recognizes two methods to quantify natamycin on shredded cheese: high performance liquid chromatography (HPLC) and spectrophotometry. Concentrations of natamycin in aqueous suspensions were determined using both methods. Results show that spectrophotometry is flawed when quantifying the amount of active natamycin because the method gives erroneously high results. The amount of active natamycin is not accurately quantified using spectrophotometric techniques because it cannot separate the active form from the inactive form of natamycin. Polymer packages containing a UV absorber (11.4% light transmission at 350 nm) allow significantly less UV-associated degradation of natamycin than those packages that lacked a UV protectant (90.0% light transmission at 350 nm) (p<0.05). Incorporating a UV absorber into a package helps protect natamycin and its various complexes from UV light degradation, which can increase the shelf life of shredded cheese. However, even with a UV absorber, natamycin is still able to degrade. Natamycin was complexed with different cyclodextrins to help better solubilize natamycin â β-cyclodextrin, hydroxy-propyl β-cyclodextrin and γ-cyclodextrin. Using cyclodextrins to apply natamycin more uniformly onto shredded cheese did not significantly increase the consistency of distribution (p<0.05). Variability was uniform throughout all treatments with the exception of HPBCD complex. After 27 days, all of the UV packages treated with each of the cyclodextrin treatments containing shredded cheese began to show visible mold growth. Those packages stored in total darkness remained mold free through the duration of the experiment ending on day 62. When untreated with natamycin and an initial concentration of 101-102 spores/gram of Penicillium roqueforti, shredded cheese remained free from visible mold growth for 24 days in total darkness at 4°C. Samples treated with one of the natamycin treatments were able to remain mold free for at least 9 more days, showing visible signs of mold growth at day 33. There was no statistical difference between the treatments of dry natamycin, aqueous suspension natamycin, β-cyclodextrin-natamycin complex, and γ-cyclodextrin-natamycin complex (p<0.05). However, there was a difference with the use of hydroxy-propyl β-cyclodextrin-natamycin complex. Hydroxy-propyl β-cyclodextrin-natamycin complex allowed the shredded cheese to last for 41 days, 17 days longer than the control sample. / Master of Science

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 &micro / g/ml except C. parapsilosis and C guilliermondii isolates. 9 dermatophyte strains were not susceptible to this protein and MICs were &gt / 64 &micro / 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.

Some yeasts secrete polypeptide toxins, which are lethal to other sensitive yeast cells, gram-positive pathogenic bacteria and pathogenic fungi. Therefore these are designated as killer toxins. Killer toxins are suggested as potent antimicrobial agents especially for the protection of fermentation process against contaminating yeasts, biological control of undesirable yeasts in the preservation of foods. Moreover they are promising antimicrobial agents in the medical field / due to immune system suppressing diseases like AIDS, there is an increase in the incidence of fungal diseases and current antimycotics have low selectivity and severe side effects. In this study our aim was to explain the cytocidal effect and enzymatic properties of K5 type yeast killer protein, which is secreted by Pichia anomala NCYC 434 cells, and known to have a broad range of killing spectrum. Competitive inhibition of the toxin with cell wall polysaccharides showed that primary binding site of toxin is &amp / #946 / -1,3-glucans of sensitive cells. Toxin showed exo-&amp / #946 / -1,3-glucanase activity which causes loss of cell wall rigidity leading cell death. Km and Vmax were found to be 0,3 mg/ml and 372,3 &micro / mol/min/mg for laminarin hydrolysis. The toxin exerted its cytocidal effect after 2 h contact with the target cells. Toxin production was found to be dependent on &amp / #946 / -1,3-glucan content of the media. Toxin activity was completely inhibited by Hg+2 ,while several metal ions and DTT increased the activity to different extends. Our findings revealed the characteristics of K5 type killer toxin which will help for its possible uses in near future.

Some yeast strains under certain conditions secrete into the medium polypeptide toxins which are inhibitory to sensitive cells. These yeast strains are termed as killer yeasts and their toxins are designated as killer proteins or killer toxins. Killer proteins are classified into 11 typical types (K1-K11). These toxins have different killing mechanisms on sensitive cells. Some of them hydrolyze major cell wall component &amp / #946 / -1,3- glucans. As mammalian cells lack cell walls research and development of novel highly selective antifungals are mostly focused on the agents which target the components of the fungal cell wall. We have previously characterized the K5 type killer protein. This protein is an exo &amp / #946 / -1,3-glucanase which is stable at pH&rsquo / s and temperatures appropriate for its medical usage. &amp / #946 / -1,3- glucan hydrolyzing activity of the K5 type killer protein highlighted the potential use of this protein as a selective antimycotic agent. Antifungal activity of the K5 type yeast killer protein was tested against 26 human pathogenic yeast and 9 dermathophyte strains and found to be affective on all of the tested strains. Toxin MIC50, MIC100 and MFC values were found to be between 0.25-4, 0.5-8, 1-8 &micro / g/ml respectively except Candida krusei isolates. Cell killing analysis revealed that toxin activity starts within first 2 hours and complete cell death time differs due to the susceptibility of strains to the K5 type yeast killer protein. K5 type yeast killer protein would be used as a novel and selective agents with the results obtained from this study.