Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Review Citation - WoS: 5Citation - Scopus: 5Development and Functionalization of Electrospun Fiber Coated Thin Film Microextraction Devices for Rapid Mass Spectrometric Determination of Biologically Important Polar Molecules(Elsevier B.V., 2024) Öztürk,M.; Salih,B.; Eroğlu,A.E.; Boyaci,E.Rapid diagnosis of diseases is one of the challenging areas in clinical research. From the analytical chemist's perspective, the main challenges are isolating the compounds from the bio-specimen and lengthy analysis times. In this regard, solid phase microextraction offers a platform to address the abovementioned challenges. Moreover, its sharp tip-thin film geometry, known as coated blade spray (CBS), can enhance the extraction and act as an ionization source in direct mass spectrometric analysis. In this study, a new CBS device specifically designed for polar analytes was prepared and optimized to determine urinary metabolites. For this purpose, polyacrylonitrile (PAN) was selected as a base polymer as it can be electrospun to form a nanofibrous structure, and it can be modified with weak ion exchange moieties to interact with polar analytes. Following the electrospinning of PAN, hydrolysis was optimized, and conditions leading to sufficient extraction enhancement without dissolving the polymer were obtained when probes were treated with 5.0 M of NaOH for 2.5 h. Using the coated blades prepared as explained, the evaluation of various extraction conditions showed that 5 min is sufficient for equilibrium extraction. In addition, the solution's ionic strength and pH significantly affect the extraction. Optimum sorption was obtained at no salt added and pH 7.0 conditions. The CBS-MS optimization showed that 10.0 µL of ACN/MeOH/H2O (40:40:20, v/v/v) with formic acid kept for 15 seconds on the blade before voltage application leads to the highest signal. The limits of quantification of the analytes are between 50 and 100 ng/mL. © 2024 Elsevier B.V.Article Citation - WoS: 1Citation - Scopus: 1Dnmso; an Ontology for Representing De Novo Sequencing Results From Tandem-Ms Data(PeerJ Inc., 2020) Takan, Savaş; Allmer, JensFor the identification and sequencing of proteins, mass spectrometry (MS) has become the tool of choice and, as such, drives proteomics. MS/MS spectra need to be assigned a peptide sequence for which two strategies exist. Either database search or de novo sequencing can be employed to establish peptide spectrum matches. For database search, mzIdentML is the current community standard for data representation. There is no community standard for representing de novo sequencing results, but we previously proposed the de novo markup language (DNML). At the moment, each de novo sequencing solution uses different data representation, complicating downstream data integration, which is crucial since ensemble predictions may be more useful than predictions of a single tool. We here propose the de novo MS Ontology (DNMSO), which can, for example, provide many-to-many mappings between spectra and peptide predictions. Additionally, an application programming interface (API) that supports any file operation necessary for de novo sequencing from spectra input to reading, writing, creating, of the DNMSO format, as well as conversion from many other file formats, has been implemented. This API removes all overhead from the production of de novo sequencing tools and allows developers to concentrate on algorithm development completely. We make the API and formal descriptions of the format freely available at https://github.com/savastakan/dnmso.Article Citation - WoS: 2Citation - Scopus: 2Changes in Protein Profiles of Multiple Myeloma Cells in Response To Bortezomib(Informa Healthcare, 2013) Turan, Taylan; Şanlı Mohamed, Gülşah; Baran, YusufThe objective of this study was to determine the changes in protein profiles of U-266 multiple myeloma cells in response to bortezomib. Bortezomib inhibited cell proliferation and increased the loss of mitochondrial membrane potential and caspase-3 activity in a dose-dependent manner. DECODON Delta2D Version 4.3 software demonstrated 37 differentially expressed protein spots: five proteins were newly formed, 10 proteins were lost, 12 proteins were up-regulated and 10 proteins were down-regulated in bortezomib-treated cells as compared to untreated cells. Some of the identified proteins after mass spectrometric analysis were as follows: apoptosis regulatory protein Siva (newly formed), caspase recruitment domain-containing protein 14 (lost), Ras-related protein Rab-25 (up-regulated), nuclear factor κB (NF-κB) p105 subunit (down-regulated). In summary, differentially expressed proteins of MM U-266 cells in response to bortezomib were analyzed and identified. The data obtained from this study may indicate the use of bortezomib for the treatment of various diseases.Article Citation - WoS: 91Citation - Scopus: 106Algorithms for the De Novo Sequencing of Peptides From Tandem Mass Spectra(Taylor & Francis, 2011) Allmer, JensProteomics is the study of proteins, their time- and location-dependent expression profiles, as well as their modifications and interactions. Mass spectrometry is useful to investigate many of the questions asked in proteomics. Database search methods are typically employed to identify proteins from complex mixtures. However, databases are not often available or, despite their availability, some sequences are not readily found therein. To overcome this problem, de novo sequencing can be used to directly assign a peptide sequence to a tandem mass spectrometry spectrum. Many algorithms have been proposed for de novo sequencing and a selection of them are detailed in this article. Although a standard accuracy measure has not been agreed upon in the field, relative algorithm performance is discussed. The current state of the de novo sequencing is assessed thereafter and, finally, examples are used to construct possible future perspectives of the field. © 2011 Expert Reviews Ltd.