Yazar "Caliskan, Sennur" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • Küçük Resim Yok
    Öğe
    Biotransformation of betulin to betulinic acid by Fusarium lacertarum BRF59, an endophytic fungus isolated from the genus Betula
    (Elsevier, 2024) Gokfiliz-Yildiz, Pelin; Caliskan, Sennur; Yildirim, Hasan; Uzel, Atac
    Betulinic acid (BA), a betulin derivative, is an important plant-based natural product. BA has many biological activities and attracts attention especially as a promising antitumour drug. Extraction from plants or semisynthesis from betulin are the common methods to obtain BA, but these methods have some drawbacks. In recent years, microbial biotransformation of betulin to BA has been anticipated as an alternative method. Betulin is abundant in the outer bark of birch (Betula spp.) and obtained from these plants, however endophytes of Betula spp. have not been investigated for biotransformation of betulin to BA before. Therefore, this study aimed to investigate the culturable endophytes of Betula pubescens var. litwinowii (Doluch.) Ashburner & McAll and to determine their biotransformation capacity of betulin to BA. To this end, bacterial and fungal endophytes were isolated from the surface-sterilized root, stem, and branch samples. A total of 37 endophytes (11 bacteria and 26 fungi) were identified by polyphasic approach. All endophytes were screened for the biotransformation of betulin to BA. Betulin and BA content of the extracts were determined by RP-HPLC analysis. Two different bacterial and fungal biotransformation processes were designed. It was found that the fungus BRF59 produced BA via betulin biotransformation under the Fungal Biotransformation Process-2 when the fungus was acclimatized to betulin before biotransformation, and glycerol was used as a carbon source, instead of glucose, during bioprocess. The highest BA yield and BA concentration was obtained as 12.22 +/- 0.94 % and 80.85 +/- 2.64 mg/ml, respectively, under non-optimized conditions. The fungal isolate BRF59, belonging to the genus Fusarium according to ITS analysis, was further identified based on RPB2 sequence analysis and found that Fusarium lacertarum. In conclusion, this study demonstrated that betulin was biotransformed to BA by an endophytic fungus isolated from the genus Betula for the first time. F. lacertarum BRF59 might be a good candidate for production of BA through betulin biotransformation and, using glycerol as a carbon source during biotransformation might enable this by-product to convert value-added chemical. (c) 2024 SAAB. Published by Elsevier B.V. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Development of a new multiplex quantitative real-time polymerase chain reaction method for Clostridium butyricum, Clostridium sporogenes and Clostridium tyrobutyricum detection in cheese
    (Elsevier, 2022) Sahiner, Asli; Caliskan, Sennur; Halat, Ece
    Late blowing is a type of microbiological spoilage that causes unwanted changes in the taste, odour and texture of cheese due to the metabolic activities of Clostridium contaminating raw milk. This study aimed to develop a multiplex quantitative real-time polymerase chain reaction (PCR) analysis method for the rapid and simultaneous detection of Clostridium butyricum, Clostridium sporogenes and Clostridium tyrobutyricum using specific primers and probes. The optimised method was determined to work with high sensitivity and specificity to quantify late-blowing Clostridium species in cheese samples. The lowest detectable gene copy number was 4.9 x 101, 7.8 x 101 and 8.5 x 101 for C. tyrobutyricum, C. butyricum and C. sporogenes, respectively. These results demonstrated that this method is a powerful tool for detecting and quantifying late-blowing agents in cheese. This is also the first multiplex qPCR study involving C. butyricum for detecting Clostridia, a late-blowing agent in cheese.
  • Küçük Resim Yok
    Öğe
    Isolation, Identification, and Antimicrobial Evaluation of Secondary Metabolite from Serratia marcescens via an In Vivo Epicutaneous Infection Model
    (Amer Chemical Soc, 2024) Karayildirim, Cinel Koksal; Sahiner, Asli; Caliskan, Sennur; Soylu, Fahri Emrah; Gokhan, Aylin; Eroglu, Ebru; Uyanikgil, Yigit
    Microbial secondary metabolites, which play a pivotal role in struggling with infectious diseases, are the new source for controlling bacterial contaminations and possess a strong antimicrobial potential. The present study is designed to evaluate the in vitro and in vivo bactericidal activities of prodigiosin against Staphylococcus aureus. For this purpose, Serratia marcescens was used to produce prodigiosin. Characterization of the prodigiosin was carried out using NMR. In addition, bioautographic detection of prodigiosin was detected by TLC. Antibacterial assays, in vivo epicutaneous infection tests, swap analyses, and histopathological examinations were determined. The results revealed that prodigiosin was detected by NMR and TLC. According to antimicrobial susceptibility tests, prodigiosin is an efficient bactericidal compound that demonstrated strong antibacterial activity toward S. aureus. In vivo, animal studies determined that the strong inhibition of S. aureus-caused epidermal infection occurs by prodigiosin at 48 h. Histopathological results showed that S. aureus + prodigiosin skin sections consist of improved and healthy tissues without any infection area compared with the S. aureus and control groups. The in vivo study verified the antibacterial results with swap analyses, and histopathological findings showed that prodigiosin is a promising microbial metabolite effective against S. aureus infection. This study proved that prodigiosin with excellent bioactivity exhibited antibacterial properties, which might possess massive potential for new therapeutic approaches using micro-organisms.
  • Küçük Resim Yok
    Öğe
    Juniperus macrocarpa endophytes isolated on standard- and plant extract supplemented-culture media- and evaluation of their antimicrobial activity
    (Univ Belgrade, Inst Botany & Botanical Garden, 2022) Caliskan, Sennur; Gokfiliz-Yildiz, Pelin; Ozmen, Aysegul; Yildirim, Hasan; Uzel, Atac
    This study aimed to investigate the endophytes of Juniperus macrocarpa collected from gesme in Izmir, Turkey, using a culture-dependent approach and to evaluate their antimicrobial activity for the first time. Since endophytes interact with phy-tochemicals of the host plant, in addition to the standard culture media, a J. mac-rocarpa extract supplemented culture media was also used for isolation to enhance the cultivability of the endophytes. Six bacteria out of twelve and three fungi out of seven were isolated from the plant extract supplemented culture media. The gen-otypic identification of the bacterial and fungal isolates was determined based on 16S rDNA and Internal Transcribed Spacer (ITS) sequence analysis, respectively. The genus Juniperus, which has ethnopharmacological uses, is rich in phytochem-icals with multiple bioactivities. Since Juniperus spp. is listed as a priority natural habitat, it is necessary to find alternative resources that could replace the bioactive compounds of these plants. Endophytes of Juniperus spp. might be good candidates as antimicrobial producers. From this point of view, the antimicrobial activity of the crude fermentation liquid of the J. macrocarpa endophytes, and also aqueous and methanolic extracts of J. macrocarpa, were evaluated using a disc diffusion assay against a panel of test microorganisms, including antibiotic resistant ones. One fungus and seven bacteria showed remarkable antimicrobial activity against at least one test microorganism. These results indicated that some endophytes of J. macrocarpa had antimicrobial properties like their host plant and could substitute these plants as a source of antimicrobials.
  • Küçük Resim Yok
    Öğe
    Quantitative Detection of Late Blowing Agents C. tyrobutyricum, C. butyricum, and C. sporogenes in Traditional Turkish Cheese by Multiplex Real-Time PCR
    (Springer, 2023) Sahiner, Asli; Caliskan, Sennur; Halat, Ece
    Late blowing, a microbiological spoilage in hard and semi-hard cheese caused by Clostridium spores in raw milk, results in high economic losses for cheese producers. This study compared the sensitivity of the newly developed multiplex qPCR method which employing novel oligonucleotide primers and fluorescent TaqMan probes, and the culture-based most probable number (MPN) method in detecting the late blowing agent Clostridium species in traditional Turkish cheese. A total of 50 naturally contaminated cheese samples obtained from producers were analysed by both methods. Clostridium tyrobutyricum was the most common species occurring in 74% of the cheese samples, followed by C. butyricum and C. sporogenes occurring in 50% and 16% of the samples, respectively. The results of the two methods were consistent in 42 out of the 50 (84%) cheese samples. Our results indicate that the multiplex qPCR method is more sensitive than the MPN method. The multiplex qPCR method provided a favourable alternative to traditional cultural methods. This alternative molecular method has great potential in the laboratory and in the field for the rapid detection of late blowing of cheese samples.