This study indicates that a fed-batch process as a good option for recombinant human SCOMT production in E. coli BL21 (DE3), and it was verified that a constant feeding process is preferable to exponential feeding strategies. An OD600 of about 40 was achieved via a constant feeding profile of 1 g glycerol/L/h,
with a maximum specific hSCOMT activity of 442.34 nmol/h/mg. Finally, we verified that a high percentage of viable cells was maintained at the end of the fermentation. The combined results of high optical densities reached in comparison with previous work with this protein in this expression system, the high specific hSCOMT activity and high cell viability at the end of the fermentation suggest Fulvestrant manufacturer that further optimization of this particular expression system is a great option for human SCOMT production, and a scale-up process could be extremely promising, giving even better results in terms of cell growth and protein productivity. The authors have declared no conflict of interest. This work was partially funded by FEDER funds through Programa Operacional Factores de Competitividade – COMPETE: FCOMP-01-0124-FEDER-027563 with the project EXPL/BBB478/BQB/0960/2012. Augusto Pedro and Filomena Silva acknowledge GDC0199 doctoral (SFRH/BD/81222/2011) and post-doctoral (SFRH/BPD/79250/2011) fellowships from Fundação para a Ciência e Tecnologia within the scope of QREN–POPH–Advanced
Formation programs co-funded by Fundo Social Europeu and MEC. D. Oppolzer Molecular motor acknowledges a fellowship (CENTRO-07-ST24_FEDER-002014 – TPCR-2-004) from Programa “Mais Centro” within the scope of QREN–POPH–Advanced Formation programs
co-funded by Fundo Social Europeu and MEC “
“The development of sensitive, selective and real-time sensors for monitoring DNA in biological samples is very important. Determination of specific DNA-sequences in clinical or food samples can result in the detection and identification of certain infectious organisms [1]. Various DNA-sensors with labeled probes have been reported; where the use of radioisotope-labeled (125I or 132P) DNA-probes have been reported frequently [2], [3] and [4]. However, apart from high sensitivities, the use of isotope-labeled reagents is restricted because of the potential danger of radioactivity. Therefore, new strategies have been introduced for labeling of DNA such as use of avidin–biotin [5], ferrocenium [6], chemiluminescent agent [7] and [8], fluorescent dye [9], and various metal nanoparticles [10] such as gold-nanoparticles [11]. Assays based on labeled reagents are among the most sensitive reported, but in general they are costly, complex and time-consuming. Alternatively, various DNA-sensors with label-free probes have been developed. Among these are piezoelectric [12], acoustic [13], optical [14] and electrochemical transduction [1]. In particular, electrochemical DNA sensors are robust, cheap and allow fast detection.