Browsing by Author "Mustafa Oskay"

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    Asphodelus aestivus (Liliaceae)' un antimikrobiyal etkisinin çukur ve disk diffüzyon yöntemiyle karşılaştırmalı olarak belirlenmesi
    (2007) Kamuran Aktaş; Mustafa Oskay; CEM AZERİ
    Kurutulup toz haline getirilen bitki, soxhlet cihazında n-bütanol ve etil alkol (60-80 °C)'de 12 saat ekstraksiyona tabi tutulmuş ve whatman no:4 ile filtre edildikten sonra 70 °C'de buharlaştırılmıştır. Antimikrobiyal aktivitenin tespiti için ekstrenin farklı konsantrasyonları çukur ve disk diffüzyon yöntemiyle bakterilere ve mayalara karşı denenmiştir. Asphodelus aestivus ekstresi (çiçek, meyve ve tüm bitki)'nin ortalama 2-15 mm arasında değişen değerlerde antimikrobiyal aktiviteye sahip olduğu belirlenmiştir. Etil alkolle elde edilen ekstre daha yüksek inhibisyon göstermiştir. Aynı ham ekstre konsantrasyonları göz önünde bulundurulduğunda çukur diffüzyon inhibisyon sonuçları, disk diffüzyon yöntemi sonuçlarından ortalama olarak biraz daha yüksek bulunmuştur. İnhibisyonun yüksek görüldüğü bazı test organizmalarına karşı MIC değerleri makrobroth yöntemiyle belirlenmiş olup, 36-90 mg/mL arasında değişmektedir. Ayrıca test organizmalarının ticari antibiyotiklere karşı duyarlılıkları belirlenerek bir karşılaştırma yapılmıştır.
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    Comparative Analysis of Alkaline Phosphatase Activity and Aerobic Spore-Forming Bacteria in Pasteurized Milk
    (2024) Mustafa Oskay
    The remaining amounts of alkaline phosphatase (ALP) enzyme in pasteurized milk should be within certain limits. High ALP enzyme level may indicate that the milk has not been pasteurized sufficiently or may be due to excessive growth of spore-forming bacteria in the milk. For this purpose, pasteurized milk samples (n=50) taken from local markets of Manisa were screened for ALP activity and spore-forming bacteria. The ALP activity of most pasteurized milk was below the 350 mU/L limit and ranged from 0 to 500 mU/L. ALP activity was found to be high in only 4% of the 50 milk samples analyzed. The presence of spore-forming bacteria was investigated in suspicious and high ALP activity samples and representative colonies of bacteria that were selected and identified based on biochemical tests. All of the isolates were Bacillus spp. and Bacillus cereus was detected in only one sample. As a result, a positive correlation between ALP activity and the existence of Bacillus spp. was observed for pasteurized milk.
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    Taxonomic characterization and secondary metabolite production of newly isolated Streptomyces sp. MC12
    (2024) Mustafa Oskay
    An actinobacterium newly isolated from soil during a screening study was identified as Streptomyces sp. MC12 (GenBank accession number: PP757795) based on 16S rRNA analysis. For secondary metabolite production, fermentation was carried out in ISP 2 broth at 30°C, pH 7.3, for seven days under shaking conditions at 180 rpm. As a result of fermentation studies, the antagonistic effect of the crude extract, obtained through ethyl acetate extraction, against various microorganisms was determined. The MIC values of the extract against Staphylococcus aureus and Escherichia coli were 101.3 µg/mL and 153.6 µg/mL, respectively. It was also found to exhibit strong antifungal activity against Penicillium spp. Streptomyces sp. MC12, which displays both antifungal and antibacterial properties, is considered a potential secondary metabolite producer for future studies, particularly in pharmacology and the biocontrol of fungal pathogens.