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    Öğe
    A cellulase-free, thermoactive, and alkali xylanase production by terrestrial Streptomyces sp CA24
    (Tubitak Scientific & Technological Research Council Turkey, 2013) Porsuk, Ilknur; Ozakin, Suleyman; Bali, Bulent; Yilmaz, Ebru Ince
    Microbial xylanases have attracted much attention because of their applications in industrial processes during the past few decades. Sixty-five terrestrial actinomycetes previously isolated from rhizospheric soils of endemic plants were tested for their ability in production of xylanase. The results revealed that 33 isolates could degrade xylan on both solid and liquid media. Extracellular xylanase production by these isolates was characterized during their growth in liquid medium. Streptomyces sp. CA24, one of the most active strains, was selected for optimization of xylanase production. The enzyme secretion was enhanced when the medium was supplemented with oat spelt xylan (0.5%) and yeast extract (0.5%) at pH 10.0. Optimization of the culture conditions resulted in a 5-fold enhancement in enzyme production (255 U/mL). The most important characteristic of the enzyme is its production over a broad pH range of 6.0-10.0 during all stationary phases. The cellulase-free xylanase was optimally active at 60 degrees C and almost 90% stable after 4 h at 50 degrees C. The high levels of enzyme production obtained under alkali batch cultivation conditions, coupled with no production of cellulase, suggests the use of the local terrestrial strain Streptomyces CA24 and/or its enzyme in industrial processes such as pulp and paper production.
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    Öğe
    The isolation of tetrangomycin from terrestrial Streptomyces sp CAH29: evaluation of antioxidant, anticancer, and anti-MRSA activity
    (Springer Birkhauser, 2016) Ozakin, Suleyman; Davis, Robert W.; Umile, Thomas P.; Pirinccioglu, Necmettin; Kizil, Murat; Celik, Gurbet; Sen, Alaattin
    A rhizosphere isolate Streptomyces sp. CAH29 was found to possess potent antibacterial and antifungal activity against a variety of test organisms. Based on 16S ribosomal ribonucleic acid sequence homology studies, this strain was found to be similar to Streptomyces stramineus (gene sequence similarity 99 %). The major bioactive metabolite produced by Streptomyces sp. CAH29 isolate was extracted, purified andidentified by nuclear magnetic resonance as tetrangomycin. This known anthraquinone-exhibited antimicrobial activity against Staphylococcus aureus, Streptococcus pyogenes, methicillin resistant Staphylococcus aureus and Candida albicans with inhibition zones of 14, 10, 12 and 8 mm, respectively. Docking results demonstrate that tetrangomycin has a similar mode of action and a comparable docking score to bind to the dehydrosqualene synthase (CrtM) enzyme of methicillin resistant Staphylococcus aureus compared to the current inhibitor. Hence, this suggests that tetrangomycin has a potential to be used as an anti-methicillin resistant Staphylococcus aureus agent. Tetrangomycin also showed moderate free radical scavenging activity with 1,1-diphenyl-2-picryl-hydrazil. Tetrangomycin apparently decreased all of the studied cytokine (pro-inflammatory: interleukin 1B, interleukin 2, tumor necrosis factor and interleukin L6 and anti-inflammatory: interleukin 10) expression levels at IC50 concentrations in A459 (adenocarcinomic human alveolar basal epithelial) and LNCAP (human prostate adenocarcinoma) cell lines. In addition, it reduced Caspase 8 and 3 mRNA levels in LNCAP and A549 cells. This study describes for the first time novel in vitro immunosuppressive function of tetrangomycin by reducing the transcription of cytokine genes.
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    Öğe
    Tetrangomycin from Streptomyces stramineus CAH29 and its antimicrobial and cytotoxic activities
    (Elsevier Science Bv, 2018) Ozakin, Suleyman; Sen, Alaattin; Ince, Ebru
    [Abstract Not Available]