1,720,965 research outputs found
Inhibitory Effects of Aptamer Targeted Teicoplanin Encapsulated Plga Nanoparticles for <i>staphylococcus Aureus</I> Strains
No full textMansuroğlu, Banu/0000-0001-8440-9118; Özalp, Veli Cengiz/0000-0002-7659-5990; UCAK, SAMET/0000-0002-3461-2481Emergence of resistance to traditional antibiotic treatments necessitates alternative delivery systems. Teicoplanin is a glycopeptide antibiotic used in the treatments of serious infections caused by Gram-positive bacteria, including Methicillin Resistant Staphylococcus aureus (MRSA). One strategy to keep up with antibiotic resistance development is to limit dose and amount during treatments. Targeted delivery systems of antibiotics have been suggested as a mechanism to slow-down the evolution of resistance and to increase efficiency of the antimicrobials on already resistant pathogens. In this study, we report teicoplanin delivery nanoparticles of Poly Lactic-co-Glycolic Acid (PLGA), which are functionalized with S. aureus specific aptamers. A 32-fold decrease in minimum inhibitory concentration (MIC) values of teicoplanin for S. aureus was demonstrated for susceptible strains and about 64-fold decline in MIC value was achieved for moderately resistant clinical isolates of MRSA upon teicoplanin treatment with aptamer-PLGA nanoparticles. Although teicoplanin delivery in PLGA nanoparticles without targeting demonstrated eightfold decrease in MIC of susceptible strains of S. aureus and S. epidermidis and twofold in MIC of resistant strains, the aptamer targeting specifically decreased MIC for S. aureus, but not for S. epidermidis. Therefore, aptamer-targeted PLGA delivery of antibiotic can be an attractive alternative to combat with some of the multi-drug resistant bacterial pathogens.Research Fund of the Yildiz Technical University [FDK-2018-3244]This work was supported by Research Fund of the Yildiz Technical University. Project Number: FDK-2018-3244
Determination of Bacterial Community Structure of Turkish Kefir Beverages Via Metagenomic Approach
No full textÖzalp, Veli Cengiz/0000-0002-7659-5990; Acar, Elif Esma/0000-0002-6264-7550; UCAK, SAMET/0000-0002-3461-2481Bacterial microbiota of industrially produced kefir beverages (n:33) consumed in Turkey was studied using a culture-independent method and a metagenomic approach. DNA extraction from non pre enriched and pre-enriched kefir samples was used for 16S rRNA amplicon sequencing. Kefirs were dominated by Firmicutes, followed by Actinobacteria and Proteobacteria phyla. The most abundant genera in non pre-enriched kefir beverages were Lactococcus followed by Streptococcus, Bifidobacterium, Lactobacillus, and Leuconostoc. Pre-enriched kefirs were dominated by Streptococcus followed by Lactobacillus, Lactococcus, Bifidobacterium, and Leuconostoc at the genus level. Psychroserpens, Desulfonispora, Pediococcus, Micromonospora, Fructobacillus, Mycobacterium, Acetobacter, Pseudopedobacter, and Clostridium XI genera were found only in pre-enriched kefirs. Kefirs displayed pH differences from 4.04 to 4.49 and the acidity was 0.617e0.987. In two samples, the lowest pH values were obtained with abundance of Lactobacillus helveticus and Streptococcus salivarius. This study broadens our viewpoint and strengthens future applications of kefir beverages in industrial and medical fields. (C)& nbsp;2022 Elsevier Ltd. All rights reserved.BioProject [PRJNA764873]The authors would like to thank Kit-ARGEM R&D Center Konya Food and Agriculture University for providing lab facilities. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The bacterial 16S rRNA gene amplicon sequencing data generated in this study using NGS was submitted to NCBI Sequence Read Archive (SRA) database with BioProject accession number PRJNA764873
Inhibitory effects of aptamer targeted teicoplanin encapsulated PLGA nanoparticles for Staphylococcus aureus strains
No full textOzalp, Veli Cengiz/0000-0002-7659-5990; Mansuroglu, Banu/0000-0001-8440-9118; UCAK, SAMET/0000-0002-3461-2481Emergence of resistance to traditional antibiotic treatments necessitates alternative delivery systems. Teicoplanin is a glycopeptide antibiotic used in the treatments of serious infections caused by Gram-positive bacteria, including Methicillin Resistant Staphylococcus aureus (MRSA). One strategy to keep up with antibiotic resistance development is to limit dose and amount during treatments. Targeted delivery systems of antibiotics have been suggested as a mechanism to slow-down the evolution of resistance and to increase efficiency of the antimicrobials on already resistant pathogens. In this study, we report teicoplanin delivery nanoparticles of Poly Lactic-co-Glycolic Acid (PLGA), which are functionalized with S. aureus specific aptamers. A 32-fold decrease in minimum inhibitory concentration (MIC) values of teicoplanin for S. aureus was demonstrated for susceptible strains and about 64-fold decline in MIC value was achieved for moderately resistant clinical isolates of MRSA upon teicoplanin treatment with aptamer-PLGA nanoparticles. Although teicoplanin delivery in PLGA nanoparticles without targeting demonstrated eightfold decrease in MIC of susceptible strains of S. aureus and S. epidermidis and twofold in MIC of resistant strains, the aptamer targeting specifically decreased MIC for S. aureus, but not for S. epidermidis. Therefore, aptamer-targeted PLGA delivery of antibiotic can be an attractive alternative to combat with some of the multi-drug resistant bacterial pathogens.Research Fund of the Yildiz Technical UniversityYildiz Technical University [FDK-2018-3244]This work was supported by Research Fund of the Yildiz Technical University. Project Number: FDK-2018-3244
Distribution, Diversity and Ecological Characteristics of Freshwater Ostracoda (Crustacea) in Shallow Aquatic Bodies of the Ankara Region, Turkey
Get PDFAlthough Turkey has a variety of wetlands of different types and sizes, many of them are threatened by human activities. To show the biological importance of these habitats, samples were randomly collected from 173 different wetland sites in the Ankara region during the summer of 2011. 31 ostracod taxa belonging to 14 genera were identified, including two species (Eucypris elliptica and Cavernocypris subterranea) that are new reports for the Turkish ostracod fauna and 19 taxa that are new reports for the region. Canonical Correspondence Analyses was able to show 58.9% of the correlation between species and environmental variables. Water temperature, moisture and dissolved oxygen were the most important (P = 0.05) factors influencing species occurrence. Increasing sampling size (number of sites) did not significantly increase the numbers of species collected at sites located at elevations between 442 and 1,520 m.a.s.l. This also implies that altitude may have a secondary role on species diversity. Unweighted Paired Group Mean Analyses illustrated four main clustering groups of ostracods, in which species are clustered according to their ecological preferences. Based on our results, suitability of habitats appears to drive ostracod distribution and diversity in these wetland sites. Results clearly showed that these habitats can harbor diverse ostracod communities that warrant conservation
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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