Person: TURAN, KADİR
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TURAN
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KADİR
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Publication Metadata only Chitosan-DNA nanoparticles: The effect of cell type and hydrolysis of chitosan on in vitro DNA transfection(TAYLOR & FRANCIS INC, 2006) TURAN, KADİR; Turan, Kadir; Nagata, KyosukeCommercial chitosan (Ch) with low (LMWCh) and medium molecular weight (MMWCh) were hydrolyzed in diluted hydrochloric acid by heating at different temperatures. The viscosity average molecular weight of Chs was gradually decreased from 450 to 14 kDa as a function of temperature. Ch fractions were used for formation of Ch-DNA nanoparticles and tested for the ability to introduce DNA into HEK293, Swiss3T3, HeLa, and MDCK cells in vitro. The average diameter of nanoparticles was 200-220 nm. The surface charge of nanoparticles varied depending on the Ch/DNA ratio. The cell lines different response to DNA transection with Ch fractions depended on molecular weight. HEK293 cells were efficiently transfected by nanoparticles prepared with Chs having a wide range of molecular weight (similar to 14-195 kDa). Swiss3T3 cells were efficiently transfected by Ch polymers with about <17 kDa. In contrast, HeLa and MDCK cells were highly resistant to DNA transfection with Ch polymers. These results strongly suggest that Ch polymers may be widely used for DNA trasnfection of the mammalian cells under optimized conditions.Publication Metadata only Dermatologic Findings in Renal Transplant Recipients: Possible Effects of Immunosuppression Regimen and p53 Mutations(ELSEVIER SCIENCE INC, 2010) TURAN, KADİR; Serdar, Z. A.; Eren, P. A.; Canbakan, M.; Turan, K.; Tellioglu, G.; Gulle, S.; Ozgezer, T.; Kara, M.; Berber, I.; Titiz, M. I.Objective. To analyze the dermatologic lesions and possible effects of immunosuppression treatment and p53 gene mutations on dermatologic findings in renal transplant recipients. Materials and Methods. The study included 163 renal transplant recipients. After dermatologic examination, cultures, and histopathologic and genetic analyses were performed. A single-strand conformation polymorphism technique was used to analyze p53 gene mutations. Patients were categorized into 3 groups according to time since the transplantation procedure. Results were analyzed using the chi(2) test, using a software program (SPSS version 13.0; SPSS, Inc, Chicago, Illinois). Results. Mean (SD) age of the 163 transplant recipients (65 women and 98 men) was 40 (11) years, and posttransplantation follow-up was 65 (55) months. The most frequently observed drug-related lesion was hypertrichosis, in 46 of 150 patients. Of 115 lesions, the most commonly observed were verruca vulgaris (n = 34) from viruses, and pityriasis versicolor (n = 21) from superficial fungal infections. Of the total group, 20 patients (12.2%) were mutation carriers. Compared with the entire cohort, the group with premalignant lesions demonstrated more p53 mutations (11% vs 50%; P = .004). Patients given cyclosporine therapy exhibited more premalignant or malignant cutaneous lesions compared with patients who received other agents (P = .03). Conclusion. Patients carrying p53 mutations developed a malignant lesion in the late posttransplantation period, which suggests the importance of prediction of risk.Publication Metadata only The Human MTCH2 Protein Has a Negative Effect On the Influenza a Virus Replication(2021-12-26) TURAN, KADİR; Ulupınar P., Çağlayan E., Turan K.Influenza A viruses have a segmented genome consists of eight single-stranded RNA molecules. Viral replication and transcription are carried out by viral RNA polymerase (RdRP), which consists of PB2, PB2 and PA subunits. During viral infection, RdRP and other viral proteins interact with several host proteins to perform their functions. In this work, mitochondrial carrier homolog 2 (MTCH2) protein, which was found to be associated with viral PA protein by yeast two-hybrid assay, was investigated its importance in terms of viral replication. In order to detect the effects of MTCH2 on virus replication in HeLa and HEK293 cells, the protein level was artificially changed. RNA interference and CRISPR/Cas9 techniques were used for down-regulation of the MTCH2. To increase the MTCH2, the HEK293 cells were transfected with pCHA-MTCH2 plasmid. The cells with altered MTCH2 transcript/protein level were infected with influenza A/WSN and A/DkPen viruses, and the viral replication was evaluated by detection of viral RNA/proteins with qPCR/Western blot techniques and plaque assays. In addition, the RdRP activities in these cells were determined by mini-replicon tests. A significant increase of viral mRNA/protein was observed in knockdown HeLa. It was shown that avian influenza A/DkPen replication was affected more. The over-expression of MTCH2 in HEK293 cells had a negative effect on the viral RdRP. These results showed that the MTCH2 is a negative cellular factor for influenza A virus. Although deletion of MTCH2 genes was detected in HEK293 cells knocked out by CRISPR/Cas9 technique, no negative effect on viral replication was observed. This situation is thought to be caused by heterozygosity or some other factors. From these results, it was concluded that the MTCH2 protein functions as a negative regulation factor for influenza A viruses. This work was supported by a grant of the Scientific and Technological Research Council of Turkey (SBAG-112S518).Keywords: Influenza a Viruses, MTCH2 Protein, Viral Rna Polymerase, PA ProteinPublication Metadata only Interaction of influenza A virus NS2/NEP protein with the amino-terminal part of Nup214(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2020) TURAN, KADİR; Senbas Akyazi, Burcak; Pirincal, Aysegul; Kawaguchi, Atsushi; Nagata, Kyosuke; Turan, KadirInfluenza A viruses have a single-stranded RNA genome consisting of 8 segments. Each RNA segment associates with the nucleoprotein (NP) and viral RNA polymerase to and from a viral ribonucleoprotein (vRNP) particle. The viral mRNA synthesis is dependent on a capped pruner derived from nascent host RNA transcripts. For these processes to take place, vRNPs must pass through the cell nuclear pore complex (NPC) to the nucleus. The influenza A virus NS2 protein, also called the nuclear export protein (NES), has an important role in the nucleocytoplasmic transport of vRNPs. This protein interacts with the host cellular nucleoporins during the nuclear export of vRNPs. In this study, the human nucleoporin 214 (Nup214) was identified as an NS2-binding protein by using a yeast two-hybrid assay. The interaction between NS2 and human Nup214 was confirmed in both yeast and mammalian cells. It has been shown that the NS2 protein interacts with the amino terminal FG domain of the Nup214 protein. The influenza viral replication was suppressed in knockdown cells for the Nup214 protein. It was concluded that the FG domains of nucleoporins have an important role in the interaction of the influenza NS2 protein with host NPC for vRNA export.Publication Metadata only TÜSEB destekli COVID-19 aşı projeleri(2021-09-09) TURAN, KADİR; Turan K.Publication Metadata only Nickel(II)-PPh3 complexes with ONS and ONN chelating thiosemicarbazones: synthesis and inhibition potential on influenza A viruses(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2018) TURAN, KADİR; Guveli, Sukriye; Turan, Kadir; Ulkuseven, BahriTetra-coordinated nickel(II) complexes of two ONS (1, 2) and seven ONN (3a-3g) chelating 2-hydroxy-3-methoxy-benzaldehyde thiosemicarbazones were synthesized. The dibasic ligands and complexes bearing PPh3 as a coligand were characterized by means of analytical and spectroscopic data. Cytotoxic activities of the ligands and nickel(II) complexes were determined using the MTT assay in vitro against MDCK cells, and then all the compounds were tested on influenza virus replication by plaque assays. The compounds showed GI(50) values varying from concentrations of 15.9 up to 161.8 mu g/mL for MDCK cells. The plaque assays indicated that one ONS (1) and two ONN (3c and 3d) chelate structures have considerable antiviral effects on influenza A viruses at lower concentrations than the GI(50) values for MDCK cells. The ligands and other complexes did not show any inhibitory effects on influenza virus plaque formation. The effects of the compounds on the influenza virus and structure-antiviral activity relationships were discussed based on the donor atoms and S-alkyl substituents.Publication Metadata only The potential of archaeosomes as carriers of pDNA into mammalian cells(TAYLOR & FRANCIS LTD, 2016) OGAN, AYŞE; Attar, Azade; Ogan, Ayse; Yucel, Sevil; Turan, KadirThis paper describes the formulation of archaeosomes and the evaluation of their abilities to facilitate in vitro DNA delivery. Lipids of the H.hispanica 2TK2 strain were used in archaeosome formation, which is formulated by mixing H.hispanica 2TK2 lipids with plasmid DNA encoding green fluorescent protein (GFP) or beta-galactosidase (beta-gal). Archaeosome/pDNA formation and unbound DNA were monitored by agarose gel electrophoresis. The archaeosome formulations were visualized by AFM and TEM. The zeta potential analysis showed the archaeosomes to be electronegative. The composition of archaeosomes and the DNA dose for transient transfection into HEK293 cells were optimized, and the relationship between the structure and activity of archaeosomes in DNA delivery was investigated. By themselves, archaeosomes showed low efficiency for DNA delivery, due to their anionic nature. By formulating archaeosomes with a helper molecule, such as DOTAP, CaCl2, or LiCl, the capability of archaeosomes for gene transfection is significantly enhanced. The transfection profiles of efficient archaeosomes are proved to have a long shelf-life when maintained at room temperature. Thus, the archaeal lipids have the potential to be used as transfection reagents in vitro.Publication Metadata only Biochemical characterization of avian influenza viral polymerase containing PA or PB2 subunit from human influenza A virus(ELSEVIER SCIENCE BV, 2018) TURAN, KADİR; Phu Tran Vinh Pham; Turan, Kadir; Nagata, Kyosuke; Kawaguchi, AtsushiAdaptive mutations in viral polymerase, which is composed of PB1, PB2, and PA, of avian influenza viruses are major genetic determinants of the host range. In this study, to elucidate the molecular mechanism of mammalian adaptation of avian viral polymerase, we performed cell-based vRNP reconstitution assays and biochemical analyses using purified recombinant viral polymerase complexes. We found that avian viral polymerase from A/duck/Pennsylvania/10,218/84 (DkPen) enhances the viral polymerase activity in mammalian cells by replacing the PA or PB2 gene with that from human influenza virus A/WSN/33 (WSN). Chimeric constructs between DkPen PA and WSN PA showed that the N-terminal endonuclease domain of WSN PA was essential for the mammalian adaptation of DkPen viral polymerase. We also found that the cap-snatching activity of purified DkPen viral polymerase was more than 5 times weaker than that of WSN in vitro in a PB2 Glu627-dependent manner. However, the cap-snatching activity of DkPen viral polymerase was hardly increased by replacing DkPen PA to WSN PA. These results suggest that the activity of viral genome replication may be enhanced in the DkPen reassortant containing WSN PA. (C) 2018 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.