The role of cavity residue leucine 95 and channel residues glutamine 204, aspartic acid 211, and phenylalanine 269 on toluene o-xylene monooxygenase activity and regiospecificity

The biocatalyst toluene-o-xylene monooxygenase (ToMO) of Pseudomonas sp. OX1 belongs to a remarkable family of bacterial multicomponent monooxygenases and has been shown to have a great potential for biotechnological and environmental applications. Structural analysis of ToMO hydroxylase revealed the presence of three hydrophobic cavities, a channel, and a pore leading from the protein surface to the active site. A structural study with the related enzyme toluene-4-monooxygenase (T4MO) hydroxylase with its respective regulatory protein confirmed that the channel undergoes extensive structural changes upon binding of the regulatory protein and transiently opens and closes during catalysis (Figure 1). Here, saturation mutagenesis was used to investigate the catalytic roles of alpha-subunit (TouA) second cavity residue L95 and TouA channel residues Q204, D211, and F269. By testing the substrates toluene, phenol, nitrobenzene, and/or naphthalene, these positions were found to influence the catalytic activity of ToMO. Several regiospecific variants were identified from TouA positions Q204, F269, and L95. For example, TouA variant Q204H had the regiospecificity of nitrobenzene changed significantly from 30 to 61 % p-nitrophenol. Interestingly, a combination of mutations at Q204H and A106V altered the regiospecificity of nitrobenzene back to 27 % p-nitrophenol. TouA variants F269Y, F269P, Q204E, and L95D improved the meta-hydroxylating capability of nitrobenzene by producing 87, 85, 82, and 77 % m-nitrophenol, respectively. Here, two additional TouA residues, S222 and A106, were also identified that may have important roles in catalysis. Most of the isolated variants from D211 remained active, whereas having a hydrophobic residue at this position appeared to diminish the catalytic activity toward naphthalene. The mutational effects on the ToMO regiospecificity described here suggest that it is possible to further fine tune and engineer the reactivity of multicomponent diiron monooxygenases toward different substrates at positions that are relatively distant from the active site. Please click Additional Files below to see the full abstract

Early diagnosis and better rhythm management to improve outcomes in patients with atrial fibrillation: the 8th AFNET/EHRA consensus conference

Aims Despite marked progress in the management of atrial fibrillation (AF), detecting AF remains difficult and AF-related complications cause unacceptable morbidity and mortality even on optimal current therapy.Methods and results This document summarizes the key outcomes of the 8th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA). Eighty-three international experts met in Hamburg for 2 days in October 2021. Results of the interdisciplinary, hybrid discussions in breakout groups and the plenary based on recently published and unpublished observations are summarized in this consensus paper to support improved care for patients with AF by guiding prevention, individualized management, and research strategies. The main outcomes are (i) new evidence supports a simple, scalable, and pragmatic population-based AF screening pathway; (ii) rhythm management is evolving from therapy aimed at improving symptoms to an integrated domain in the prevention of AF-related outcomes, especially in patients with recently diagnosed AF; (iii) improved characterization of atrial cardiomyopathy may help to identify patients in need for therapy; (iv) standardized assessment of cognitive function in patients with AF could lead to improvement in patient outcomes; and (v) artificial intelligence (AI) can support all of the above aims, but requires advanced interdisciplinary knowledge and collaboration as well as a better medico-legal framework.Conclusions Implementation of new evidence-based approaches to AF screening and rhythm management can improve outcomes in patients with AF. Additional benefits are possible with further efforts to identify and target atrial cardiomyopathy and cognitive impairment, which can be facilitated by AI.</p

Treatment Of Reactive Dye Bath Effluents Used In Textile Industry With Electrochemical Methods

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2006Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2006Bu çalışmada, bir tekstil reaktif boya banyosunun çelik ve alüminyum elektrotlar kullanılarak elektrokimyasal yöntemler ile arıtımı incelenmiş, başlangıç pH’sı, akım yoğunluğu, elektrolit tipi, süre ve elektrot malzemesi gibi işletme parametrelerinin ve ayrıca NaCl, Na2CO3 ve iyon tutucu gibi boya banyo bileşenlerinin proses verimi üzerine etkileri KOİ ve renk parametreleri ile AOX oluşum potansiyeli ve biyolojik arıtılabilirlikteki iyileşme bazında belirlenmiştir. Elde edilen veriler koagülasyon-flokülasyon ve Fenton oksidasyonu deneylerinden elde edilen sonuçlar ile mukayese edilmiş ve çalışılan koşullarda gerek Fenton oksidasyonu gerekse çelik ve alüminyum elektrotların kullanıldığı elektrokimyasal arıtma ile oldukça yüksek verimde KOİ gideriminin sağlandığı görülmüştür. FeSO4 koagülasyonu, Fenton oksidasyonu ve çelik elektrot ile elektrokoagülasyon ise renk giderimi açısından etkin bulunmuştur. Deneysel çalışma çerçevesinde belirlenen optimum işletme koşulları sağlandığında çelik elektrot ile elektrokoagülasyonun tekstil endüstrisi atıksularının arıtımında başarı ile kullanılabileceği sonucuna varılmıştır.In this study, treatment of a reactive dye bath effluent with electrochemical treatment methods by using steel and aluminum electrodes was investigated and the effect of operational parameters such as pH, current density, type of electrolyte, time, type of electrode material and also dye bath components such as NaCl, Na2CO3 and sequestering and dispersing agent on process efficiency was determined on the basis of COD and color parameters as well as AOX formation potential and improvement of biological treatability. These results were compared with the results of coagulation-flocculation and Fenton experiment results. Results have indicated that very high removal efficiency was obtained with both Fenton oxidation and electrochemical treatment with steel and aluminum electrodes at studied conditions. FeSO4 coagulation, Fenton oxidation and electrocoagulation with steel electrodes were found effective for color removal. It has been concluded that this technology can be successfully used for treatment of textile wastewaters when the optimum operational conditions that are determined in this experimental study are obtained.Yüksek LisansM.Sc

Şahap Sıtkı İlter And Hıs Storytellıng

Bu çalışma, Türk hikâyeciliğinin unutulmuş isimlerinden biri olan Şahap Sıtkı İlterzin hikâyelerini çözümlemek ve yazarın kültür hayatımızdaki yerini belirlemek amacıyla yapılmıştır. Çalışmanın ilk bölümünde yazarın hayatı ve edebî kişiliği hakkında bilgi verilmiş, ikinci bölümde ise yazarın yayımlanan beş hikâye kitabı kronolojik olarak incelenmiştir. Her kitap; zihniyet, yapı, tema ve anlatım başlıkları altında ayrı ayrı değerlendirilmiştir. Şahap Sıtkı İllterzin 1957 yılından 1971 yılına kadar yayımlanan beş hikâye kitabında elli iki hikâye vardır. Eleştirel gerçekçi bir bakış açısına sahip olan yazar, hikâyelerinde çoğunlukla işçileri, balıkçıları ve küçük insan diye tabir edebileceğimiz kişileri anlatmıştır. Ayrıca aydınları ve sanatçıları da ele almıştır. Hikâyelerinde tekniğe, söyleyişe ve seçtiği temaya çok önem veren yazarın tüm hikâyeleri birbirine yakın özellikler göstermektedir. Şahap Sıtkı İlter edebiyata şiirle başlamış; roman, tiyatro ve anı gibi türlerde de eser vermiştir. Ayrıca Batı edebiyatından dilimize çok sayıda eser tercüme etmiştir. Ancak yazarın en başarılı olduğu tür hikâyedir.The aim of this study is to determine the place of Şahap Sıtkı İlter, who is one of the forgotten writers in Turkish literature, and examine his stories by making use of textual analysis methods. In first chapter, some information is given about his life and his works is examined in second chapter. The emphasis here is on the elements that differ in terms of mentality, structure, theme and narration. There are fifty two stories in Şahap Sıtkı İlterzs books which published between 1957 and 1971. His point of view based on critical realism and his stories about people who have simple lives. He also wrote about intellectuals and artists. All of his stories show similar features. Şahap Sıtkı İlter started his literary life with poetry. He also wrote in other literary genres like novel, theatre, memories. He also interested in interpretation. But his most successful works are his stories

The comparison of endothelial function of moderate intensity interval exercise with continuous exercise in healthy men

Background/aim: Exercise enhances endothelium-dependent vasodilation; however, it is unclear whether intermittent exercise has a different effect on vascular endothelial function compared to continuous exercise. This study aimed to compare vascular endothelial function following intermittent exercise including short rest intervals with continuous exercise, both at the anaerobic threshold level. Materials and methods: Peak oxygen consumption (VO2 peak) and anaerobic threshold were measured in physically active healthy young men (n = 12) by breath-by-breath analysis. After completion of intermittent exercise consisting of eight 1-min long intervals at the anaerobic threshold intensity with 75-s rest periods, total work was calculated. Equivalent work was done during continuous exercise. Immediately after the two exercise periods, venous blood lactate, endothelial nitric oxide synthase (eNOS), endothelin-1, N-terminal proANP (NTproANP), N-terminal proBNP (NTproBNP), and N-terminal proCNP (NTproCNP) levels were measured. Brachial artery flow-mediated dilatation (FMD) was measured before exercise and 30 min after exercise. Results: Mean VO2 peak level was 33.42 ± 5.9 ml/min/kg and anaerobic threshold level was 47.33 ± 5.85%. Lactate levels following continuous exercise were higher than levels following intermittent exercise (27.76 ± 7.43 mg/dl, 18.54 ± 4.87 mg/dl respectively; p˂0.05). Endothelin-1, eNOS, NTproANP, NTproBNP, and NTproCNP levels were similar after both modalities of exercise (p > 0.05). No significant difference was found in FMD response when comparing intermittent and continuous exercise (7.05 ± 15.11%, 2.49 ± 16.24% respectively; p > 0.05). Conclusion: Since blood lactate levels are higher following continuous exercise, individuals who find difficulty exercising may prefer an intermittent form of exercise. However, both intermittent and continuous exercise at the anaerobic threshold level seem to not produce a significant acute change in endothelial function in healthy men

Pulmonary microvascular permeability and gas exchange in patients with syndrome X

Aim: This clinical study was planned to assess pulmonary microvascular permeability in patients with Syndrome X (SX) by using a functional imaging tool, technetium-99m-diethyltriaminepentaaceticacid (Tc-99m-DTPA) lung clearance scintigraphy, and the pulmonary functions test, which includes diffusion capacity of the lung for carbon monoxide (DLCO)

COX-2 EXPRESSION IN NON ALCOHOLIC STEATOHEPATITIS WITH AND WITHOUT FIBROSIS

62nd Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases (AASLD) -- NOV 04-08, 2011 -- San Francisco, CAWOS: 000295578004105Amer Assoc Study Liver Di