Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Human Immunodeficiency Virus Type-1 Tat Protein Induces Secretory Leukocyte Protease Inhibitor Expression in African Green Monkey but Not Human Cells(Springer, 2020) Özdemir, Selçuk; Şengez, Burcu; Arslanoğlu, AlperAfrican monkeys are resistant to HIV-1 infection due to intrinsic restriction mechanisms found in their cells. However, although they can be infected by monkey-adapted modified HIV-1 particles that are designed to overcome known restriction factors, virus numbers drop to undetectable levels in immunocompetent animals. These results indicate the possibility of the presence of yet unidentified factor(s) that restrict HIV-1 in old-world monkey (OWM) cells after integration of the viral genome into the host cell chromosome. In the light of these findings, we hypothesized that OWMs might have evolved resistance mechanism(s) against HIV-1 by switching specific gene(s) on in response to the synthesis of viral proteins in infected cells. In an attempt to mimic post-infection status, we expressed HIV-1 Tat gene in African green monkey cells and compared the whole proteome with normal cells and identified secretory leukocyte protease inhibitor (SLPI), a protein with known extracellular anti-HIV-1 activity, as an over-expressed protein in the presence of HIV-1 Tat protein by 2D-PAGE and mass spectrometry analysis. We also showed that overexpression of SLPI in the presence of HIV-1 Tat was specific to monkey cells. Our results also suggest that SLPI had a previously undiscovered intracellular anti-HIV activity in addition to its extracellular activity.Article Citation - WoS: 27Citation - Scopus: 36Purification and Biochemical Characterization of an Extracellular Lipase From Psychrotolerant Pseudomonas Fluorescens Ke38(TUBITAK, 2013) Adan Gökbulut, Aysun; Arslanoğlu, AlperAn extracellular lipase producing bacterium was isolated from a soil sample, and identified as a strain of Pseudomonas fluorescens by 16S rRNA gene sequencing. It was named Pseudomonas fluorescens KE38. KE38 showed psychrotolerant properties with an optimum growth temperature of 25 °C. The lipase enzyme secreted by KE38 was purified 41.13-fold with an overall yield of 54.99%, and a specific activity of 337.3 U/mg. The molecular mass of purified lipase was estimated to be approximately 43 kDa by SDS-PAGE. Although the lipase was active at a temperature range of 15-65 °C, it exhibited maximum activity at 45 °C, at pH 8.0. The enzyme exhibited high stability retaining 100% and 70% of its activity after an incubation period of 45 and 100 min at 45 °C and pH 8.0 respectively. It also showed a broad substrate specificity acting on p-nitrophenyl esters with C8-C18 acyl groups as substrates and was activated by Ca2+ and Ni2+ at 1 mM. While the enzyme retained its activity levels in the presence of a variety of organic solvents, DMSO and dimethylformamide enhanced this. High stability, broad substrate specificity and activity at cold temperatures in the presence of organic solvents, and metal ions make the extracellular lipase of KE38 a candidate for industrial applications.Article Citation - WoS: 39Citation - Scopus: 49Production of Antimicrobial Films by Incorporation of Partially Purified Lysozyme Into Biodegradable Films of Crude Exopolysaccharides Obtained From Aureobasidium Pullulans Fermentation(University of Zagreb, 2005) Kandemir, Nilay; Yemenicioğlu, Ahmet; Mecitoğlu, Çiğdem; Elmacı, Zehra Seda; Arslanoğlu, Alper; Göksungur, Mehmet Yekta; Baysal, TanerAntimicrobial films were produced by incorporating partially purified lysozyme into films of crude exopolysaccharides (59% pullulan) obtained from Aureobasidium pullulans fermentation. After film making, the films containing lysozyme at 100, 260, 520 and 780 μg/cm2 showed 23 to 70% of their expected enzyme activities. The highest recovery of enzyme activity (65-70%) after the film making was obtained in films prepared by incorporating lysozyme at 260 μg/cm2 (1409 U/cm2). The incorporation of disodium EDTA·2H2O and sucrose did not affect the initial lysozyme activity of the films significantly. With or without the presence of disodium EDTA·2H2O at 52 or 520 μg/cm2, lysozyme activity showed sufficient stability in the films during 21 days of cold storage. However, the presence of sucrose at 10 mg/cm2 in the films caused the destabilization of part of enzyme activity (almost 35%) at the end of storage. The combinational incorporation of lysozyme at 780 μg/cm 2 (4227 U/cm2) and disodium EDTA·2H2O at 520 μg/cm2 gave antimicrobial films effective on Escherichia coli. However, in the studied lysozyme concentration range the films did not show any antimicrobial activity against Lactobacillus plantarum. This study clearly showed that the partially purified lysozyme and crude exopolysaccharides from Aureobasidium pullulans may be used to obtain antimicrobial films to increase the safety of foods.