Browsing by Author "Usta, Alev"

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Effects of psychotropic drugs as bacterial efflux pump inhibitors on quorum sensing regulated behaviors
(Slovak Univ Agriculture Nitra, 2014-08-22) Aybey, Aynur; Usta, Alev; Demirkan, Elif; Aybey, Aynur; Usta, Alev; DEMİRKAN, ELİF; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Biyoloji Bölümü.; 0000-0003-2743-9745; 0000-0002-5292-9482; ABI-4472-2020; CJN-1872-2022; GFJ-9415-2022
Psychotropic drugs are known to have antimicrobial activity against several groups of microorganisms. The antidepressant agents such as duloxetine, paroxetine, hydroxyzine and venlafaxine are shown to act as efflux pump inhibitors in bacterial cells. In order to the investigation of the effects of psychotropic drugs were determined for clinically significant pathogens by using standart broth microdillusion method. The anti-quorum sensing (anti-QS) activity of psychotropic drugs was tested against four test pathogens using the agar well diffusion method. All drugs showed strong inhibitory effect on the growth of S. typhimurium. Additionally, quorum sensing-regulated behaviors of Pseudomonas aeruginosa, including swarming, swimming and twitching motility and alkaline protease production were investigated. Most effective drugs on swarming, swimming and twitching motility and alkaline protease production, respectively, were paroxetine and duloxetine; duloxetine; hydroxyzine and venlafaxine; paroxetine and venlafaxine; venlafaxine. Accordingly, psychotropic drugs were shown strongly anti-QS activity by acting as bacterial efflux pump inhibitors and effection on motility and alkaline protease production of P. aeruginosa.
Screening of phytate hydrolysis Bacillus sp. isolated from soil and optimization of the certain nutritional and physical parameters on the production of phytase
(Walter De Gruyter GMBH, 2014) Demirkan, Elif; Baygın, Eren; Usta, Alev; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Biyoloji Bölümü.; ABI-4472-2020; 23469245200; 56246525800; 56246773200
Objective: To isolate phytase producing Bacillus sp. from soil samples of Turkey, and optimize the growth conditions for maximum production of phytase. Material and Methods: The screening of isolates was performed on phytase screening medium. The best producer was selected. Phytase activity was determined by measuring the amount of liberated inorganic phosphate. Optimal culture conditions and fermentation parameters for phytase production were assessed. Results: 236 Bacillus sp. strains isolated. The best phytase producing strain showed higher enzyme yield in the presence of wheat bran and lactose as carbon source, meat extract as organic nitrogen source, CaCl2 as metal source. 0.3% as phytate concentration was found to be best. In the physical parameters, the best results was obtained at 35 degrees C, pH 7.5, 200 rpm as agitation rate, 2-4% as inoculum size and 48 h as inoculum age. A new medium was obtained by optimizing the incubation conditions of phytase production from Bacillus sp. EBD 9-1. In this medium, enzyme yield was enhanced 62% compared to basal medium. Conclusion: The present study suggests that the novel Bacillus sp. phytase enzyme may have wide industrial application, and can be used as an animal feed additive.
The effect of growth parameters on the antibiotic activity and sporulation in bacillus spp. isolated from soil
(Slovak Univ Agriculture Nitra, 2013-04-01) Usta, Alev; Demirkan, Elif; Usta, Alev; DEMİRKAN, ELİF; Uludağ Üniversitesi; 0000-0002-5292-9482; ABI-4472-2020; GFJ-9415-2022
Fifty-two Bacillus strains, which were isolated from different soil samples, were screened for antibiotic properties. The Bacillus strains were checked for antibacterial properties by the cross-streak method against 5 test pathogens, and 25 Bacillus strains had an effect on the test microorganisms. One strain of Bacillus, which exhibited the largest inhibition zone (25 mm) against Shigella sonnei, was named Bacillus sp. EA62. The antibacterial activity from Bacillus sp. EA62 was tested in six different culture media against Shigella sonnei using the agar well diffusion method. The best activity medium was selected and used for further studies. The influence of the incubation period, pH, and different glucose and nitrogen concentrations on the antibacterial activity was studied. The optimal conditions for the strongest antibiotic activity were found to be 72 hours (18 mm), pH 7.5 (23 mm), 3% glucose (25 mm), and 0.3% nitrogen concentration (23 mm). Additionally, the relationship between the antibiotic activity and sporulation was investigated. Accordingly, it was determined that the increase of the activity paralleled sporulation.
Topraktan antibiyotik üreten Bacillus sp.' lerin taranması, antibiyotik üretimi üzerine bazı parametrelerin etkisi ve sporulasyonla ilişkisinin belirlenmesi
(Uludağ Üniversitesi, 2012) Usta, Alev; Demirkan, Elif; Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Biyoloji Anabilim Dalı.
Bu çalışmada, Türkiye' nin 25 farklı ilinden alınan toprak örneklerinden 57 adet antibiyotik potent bakteri izole edilmiştir. 57 bakterinin morfolojik ve fizyolojik özellikleri araştırılmış ve 52 bakteri Bacillus cinsi olarak belirlenmiştir. Bacillus türleri karşıt-çizgi metodu ile antibiyotik üretimi için taranmıştır. Antibiyotik üretim testleri, 25 Bacillus suşunun kullanılan test mikroorganizmaları üzerinde etkili olduğunu göstermiştir. Shigella sonnei ile en büyük inhibisyon zonuna (25 mm) sahip Bacillus' un bir suşu seçilmiş ve Bacillus sp. EA62 olarak isimlendirilmiştir.Bacillus sp. EA62' den antibiyotik üretimi 6 farklı ortamda test edilmiş ve antibiyotik üretimi Shigella sonnei' ye karşı agar kuyu difüzyon metodu ile tespit edilmiştir. Bir ortam en büyük inhibisyon zonunu (15 mm) göstermiştir ve bu ortam daha sonraki çalışmalar için seçilmiştir. Seçilen bu ortamda antibiyotik üretimi ile sporulasyon arasındaki ilişki araştırılmıştır. Buna göre, antibiyotik üretimindeki artış ile sporulasyonun paralel olduğu belirlenmiştir.Bacillus sp. EA62' den antibiyotik üretimi için farklı üretim şartlarının optimizasyonu (inkübasyon zamanı, pH, glukoz ve nitrojen konsantrasyonları) gerçekleştirilmiştir. Seçilen izolattan antibiyotik üretimi için optimum koşullar 72. saat (15 mm), pH 7.5 (23 mm), % 3 glukoz (25 mm) ve % 0.3 yeast ekstrakt (23 mm) olarak bulunmuştur.Bu yeni izole edilen suş endüstriyel ölçekte büyük bir potansiyele sahip olabilir.