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A simple, fast, inexpensive sensitive/selective nucleic acid sensor based on the quartz crystal microbalance system (QCM) was developed for the detection of telomerase. A specially designed oligonucleotide probe, that is complementary to the template region of the telomerase enzyme, was immobilized onto the silver electrodes of piezoelectric crystals with polyethyleneimine adhesion cross-linked with glutaraldehyde. Optimum coating and immobilization conditions were determined. The QCM nucleic acid sensor was used for the detection of telomerase enzyme in human cervix carcinoma cell (HeLa) lysates. A significant difference between the telomerase negative cells (BHK) from HeLa cells, which was used for qualitative and quantitative detection of telomerase. An almost a linear correlation with the protein concentration was obtained with a R 2 value of 0.9621. The linear correlation coefficients (R2) for HeLa and BHK cell lysate obtained by applying Langmuir adsorption model, were 0.9630 and 0.9766, respectively. Telomerase activity was confirmed by stretch-PCR and fluorometric (F)-TRAP within HeLa extracts. The results obtained both with the QCM system developed in this study and F-TRAP method applied is significantly correlated (r = 0.968, p<0.001).

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Objective: Genotoxic potentials of six selected nitrobutane (I) derivatives designed as drug agents were tested here for the first time using umu-microplate test system. An important principle in drug development is to perform safety tests of previously determined significant drug activity in in vitro assays. This may be even more crucial than its efficiency in terms of experimental conditions, since it is important in chemotherapy to treat without risk for the patient. Methods: Umu-microplate test system is especially designed for detecting the mutagenicity of nitro compounds. 1-[(2-aminophenyl)thio]-1-phenyl-2-nitrobutane (I) derivatives involve nitro groups. Therefore umu-microplate test system has been chosen for our analysis. Evaluation of the SOS inducing activity of the tested compounds was examined with the umu-microplate test system using Salmonella typhimurium NM1011 (overexpressed NR (nitroreductase)) and S.typhimurium NM2009 (overexpressed O-At (O-acethyltransferase))strains which are sensitive to nitro compounds. Chlorophenol red-β-D-galactopyranoside (CPRG) and O-nitrophenyl-β-D-galactopyranoside (ONPG) were used as substrate in the enzyme assays and also the well-known genotoxic nitro compound, 4-nitroquinoline 1-oxide (4NQO), was the positive control in the test. Results: Although the β-galactosidase activities with using CPRG were three fold higher than ONPG, parallel results were obtained for both substrates and strains with all compounds tested. For all compounds, the induction of umuC gene expression was found to be almost the same for the strains that overexpress NR and O-At. The derivatives tested didn't caused an evident induction in both strains overexpressed NR and O-At enzymes which have a role in metabolic activation mechanism of nitro compunds. Conclusion: Our study showed that, 1-[(2-aminophenyl)thio]-1-phenyl-2-nitrobutane derivatives have no genotoxic effects in this test system. This result is a very important data making them a potential drug candidate. Key Words: Nitro compounds, umu-microplate, genotoxicity, drug Conflict of Interest: Authors have no conflict of interest. ÖZETAmaç: Bu çalışmada, ilaç etken maddesi olarak tasarlanmış altı adet nitrobütan türevinin genotoksik potansiyelleri, umu-mikroplak test sistemi ile değerlendirilmiştir. İn vitro testlerde anlamlı bir ilaç aktivitesinin saptanması durumunda, güvenlik testlerinin uygulanması, ilaç geliştirmede çok önemli bir ilkedir. Kemoterapide hastayı risk oluşturmadan tedavi etmek esas olduğundan, güvenlik testleri ilacın deneysel koşullardaki etkinliğinden bile daha fazla önem taşıyabilir. Metod: Umu-mikroplak test sistemi özel olarak nitrolu bileşiklerin mutajenitesini saptamak için tasarlanmıştır. 1-[(2-aminofenil)tiyo]-1-fenil-2-nitrobütan (I) türevleri de nitro grubu içermektedir, bu nedenle çalışmamızda bu test sistemi seçilmiştir. SOS indükleme aktivitelerinin değerlendirildiği umu-mikroplak test sisteminde, nitrolu bileşiklere hassas olarak geliştirilmiş, NR (nitroredüktaz) enzimini normalden fazla ifade e...