Yazar "Aras, E. Sumer" seçeneğine göre listele

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    ANALYSES OF parC AND gyrA MUTATIONS IN CIPROFLOXACIN-RESISTANT AND SUSCEPTIBLE pseudomonas aeruginosa ISOLATED FROM SOIL BY PCR-RFLP AND SSCP METHOD
    (Slovak Univ Agriculture Nitra, 2018) Avsar, Cumhur; Aras, E. Sumer
    The aims of this study were to assess the prevalence of gyrA and parC mutations in ciprofloxacin-resistant and susceptible Pseudomonas aeruginosa isolated from soil and to evaluate the suitability of the restriction fragment length polymorphism (RFLP) and single-strand conformation polymorphism (SSCP) techniques as screening methods for molecular characterizations of ciprofloxacin resistance. From the examined 21 P. aeruginosa isolates 9 strains were resistant to ciprofloxacin. These 21 P. aeruginosa isolates and one control strain were analyzed for alterations in the ciprofloxacin resistance determining region of gyrA and parC by RFLP and SSCP analyses. The PCR reaction confirmed the presence of the gyrA and parC genes in all of the strains. PCR-RFLP analyses with SacII for gyrA and Hinfl for parC were performed as a screening method. We found that 18 and 17 out of 22 isolates have SacII and Hinfl restriction site and 4 and 5 strains did not have the site recognized by these enzymes, respectively. Seven for gyrA and fourteen for parC PCR products were electrophoresed for SSCP. By SSCP analysis, 21 (in parC) and 15 (in gyrA) different band patterns were detected, and each pattern corresponded to a distinct mutation. As a result, the RFLP and SSCP methods are suitable for a molecular screening of ciprofloxacin resistant and susceptible P. aeruginosa isolates. SSCP analysis can also provide advantage for the detection of novel and multiple mutations. In addition, we can say that environmental monitoring followed by clinical surveillance can be successful in uncovering previously unrecognized cases of infection.
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    Community structures and comparison of nosZ and 16S rRNA genes from culturable denitrifying bacteria
    (Springer, 2020) Avsar, Cumhur; Aras, E. Sumer
    The objectives of this study were (i) to isolate and characterize of cultivable denitrifying bacteria using classic microbiological and molecular methods, (ii) to compare of 16S rRNA and nosZ genes as molecular markers, (iii) to determine bacterial community structure and diversity in soil samples using single-strand conformation polymorphism (SSCP) analysis. In this study, 49 bacterial isolates were cultivated and phylogenetic analyses grouped them into two phyla: Proteobacteria (37 species) and Firmicutes (12 species). Our study showed that the nosZ functional gen could be used to identify denitrifying bacteria abundance in environment but could not be used to identify pure bacterial cultures. In addition, the bacterial community structure showed significant differences among the various soil types. Phylogenetic analysis of community structure indicated that 51 clones could be divided into 2 phylotypes. Uncultured bacteria (80.4%) and Gammaproteobacteria (19.6%) were the dominant components of the soil bacterial community. For 16S rRNA, PCR products of 49 bacteria were obtained with 27F-1492R primer pairs. For nosZ, PCR products were obtained with primers 1F-1R (259 bp), 2F-2R (267 bp), and F-1622R (453 bp) of 39 bacteria that the single nosZ band provided on the agarose gel. The bacterial 16S rRNA gene clone library was dominated by Gammaproteobacteria and Bacilli. The nosZ clone sequences did not represent the bacteria from which they were obtained but were found to be closer to the environmental clones. Our study showed that the nosZ functional gene could be used to identify denitrification abundance in environment but could not be used to identify pure bacterial cultures. It was also found that the nosZ sequences showed uncultured denitrifier species.
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    Phenotypic and genotypic characterization of foodborne bacteria isolated from Sinop Province, Turkey
    (Taylor & Francis Inc, 2017) Avsar, Cumhur; Civek, Seyhan; Aras, E. Sumer
    In this study, genotypic and phenotypic characteristics of the strains, antibiotic susceptibility, and antibiotic resistance genes of the Escherichia coli, Bacillus cereus, Listeria spp., and Salmonella spp. isolated from various animal foods in Sinop province were determined. Resistance percentages of the isolated strains to the antibiotics penicillin, vancomycin, clindamycin, tetracycline, ampicillin/sulbactam, gentamicin, ciprofloxacin, and chloramphenicol were 87.8, 71.9, 69.7, 63.4, 27.5, 23.1, 20.9, and 13.4%, respectively. Antibiotic resistance genes tetA, bla(CMY-2), and cat1 were found in 45, 21.25, and 6.25% of all the strains, respectively. The virulence genes were also investigated in the isolated in E. coli strains; the eae gene was found in 13.1% of the strains, while the stx1 was not identified in any strains. As a result, we can say that SDS-PAGE method may provide discrimination at species level; however, surveys at subspecies level demand molecular approaches such as ERIC and (GTG)(5)-PCR. In addition, we can suggest that molecular techniques may be especially helpful in the rapid identification of multidrug-resistant and isolates with virulence genes. This study has revealed that the investigated bacteria in animal foods is a significant reservoir of resistance genes.
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    Quantification of denitrifier genes population size and its relationship with environmental factors
    (Springer, 2020) Avsar, Cumhur; Aras, E. Sumer
    The objectives of this study were to use real-time PCR for culture-independent quantification of the copy numbers of 16S rRNA and denitrification functional genes, and also the relationships between gene copy numbers and soil physicochemical properties. In this study, qPCR analysis of the soil samples showed 16S rRNA, nirS, nirK, nosZI and nosZII average densities of 3.0 x 10(8), 2.25 x 10(7), 2.9 x 10(5), 4.0 x 10(6) and 1.75 x 10(7) copies per gram of dry soil, respectively. In addition, the abundances of (nirS + nirK), nosZI and nosZII relative to 16S rRNA genes were 1.4-34.1%, 0.06-3.95% and 1.3-39%, respectively, confirming the low proportion of denitrifiers to total bacteria in soil. This showed that the non-denitrifying nosZII-type bacteria may contribute significantly to N2O consumption in the soil. Furthermore, the shifts in abundance and diversity of the total bacteria and denitrification functional gene copy numbers correlated significantly with the various soil factors. It is the first study in Turkey about the population size of denitrification functional genes in different soil samples. It also aims to draw attention to nitrous oxide-associated global warming.