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Veiga, T. (author), Solis-Escalante, D. (author), Romagnoli, G. (author), Ten Pierick, A. (author), Hanemaaijer, M. (author), Deshmuhk, A. (author), Wahl, A. (author), Pronk, J.T. (author), Daran, J.M. (author)The industrial production of penicillin G by Penicillium chrysogenum requires the supplementation of the growth medium with the side chain precursor phenylacetate. The growth of P. chrysogenum with phenylalanine as the sole nitrogen source resulted in the extracellular production of phenylacetate and penicillin G. To analyze this natural pathway...journal article 2011
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Boender, L.G.M. (author), Van Maris, A.J.A. (author), De Hulster, E.A.F. (author), Almering, M.J.H. (author), Van der Klei, I.J. (author), Veenhuis, M. (author), De Winde, J.H. (author), Pronk, J.T. (author), Daran-Lapujade, P.A.S. (author)Extremely low specific growth rates (below 0.01 h?1) represent a largely unexplored area of microbial physiology. In this study, anaerobic, glucose-limited retentostats were used to analyse physiological and genome-wide transcriptional responses of Saccharomyces cerevisiae to cultivation at near-zero specific growth rates. While quiescence is...journal article 2011
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Boender, L.G.M. (author), Almering, M.J.H. (author), Dijk, M. (author), Van Maris, A.J.A. (author), De Winde, J.H. (author), Pronk, J.T. (author), Daran-Lapujade, P. (author)Cultivation methods used to investigate microbial calorie restriction often result in carbon and energy starvation. This study aims to dissect cellular responses to calorie restriction and starvation in Saccharomyces cerevisiae by using retentostat cultivation. In retentostats, cells are continuously supplied with a small, constant carbon and...journal article 2011
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Bakker, J.J.W. (author), Zieverink, M.M.P. (author), Kapteijn, F. (author), Moulijn, J.A. (author), Kreutzer, M.T. (author)Segmented flow in standard GC capillary columns, with a heterogeneous Pd catalyst on the walls, gave rapid information about catalytic processes in them. The residence time and conversion was monitored visually, greatly simplifying bench-scale optimization. Examples show the benefits of the elimination of pore diffusion and axial dispersion....journal article 2011
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Stallinga, S. (author)A theory of optical trapping at low Numerical Aperture (NA) is presented. The theory offers an analytical description of the competition between the stabilizing gradient and destabilizing scattering force. The trade-off can be characterized by a single dimensionless trapping parameter, which increases with bead size to wavelength ratio ?/?, m,...journal article 2011
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Daran, J.M. (author), Pronk, J.T. (author), Driessen, A.J.M. (author), Nijland, J.G. (author), Lamboo, F. (author), Puig-Martinez, M. (author), Veiga, T. (author), Gombert, A.K. (author)Penicillium chrysogenum is widely used as an industrial antibiotic producer, in particular in the synthesis of ß-lactam antibiotics such as penicillins and cephalosporins. In industrial processes, oxalic acid formation leads to reduced product yields. Moreover, precipitation of calcium oxalate complicates product recovery. We observed oxalate...journal article 2011
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Rosso, M. (author), Van Steijn, V. (author), De Smet, L.C.P.M. (author), Sudhölter, E.J.R. (author), Kleijn, C.R. (author), Kreutzer, M.T. (author)A self-similar reaction front develops in reactive ion etching when the ions penetrate channels of shallow height h. This relates to the patterning of microchannels using a single-step etching and bonding, as described by Rhee et al. [Lab Chip 5, 102 (2005)] . Experimentally, we report that the front location scales as xf ? ht1/2 and the width...journal article 2011
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Voortman, L.M. (author), Stallinga, S. (author), Schoenmakers, R.H.M. (author), Van Vliet, L.J. (author), Rieger, B. (author)Today, the resolution in phase-contrast cryo-electron tomography is for a significant part limited by the contrast transfer function (CTF) of the microscope. The CTF is a function of defocus and thus varies spatially as a result of the tilting of the specimen and the finite specimen thickness. Models that include spatial dependencies have not...journal article 2011
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Geraldes, C.F.G.C. (author), Djanashvili, K. (author), Peters, J.A. (author)Recently, many research activities in medical diagnosis have been devoted to molecular imaging with MRI. A key issue is the evaluation of molecular targets that allow the early detection and characterization of diseases and the assessment of the effects of therapy. The majority of the current targeting vectors are peptides and proteins; reports...journal article 2010
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Kulichikhin, V. (author), Semakov, A. (author), Karbushev, V. (author), Makarova, V. (author), Mendes, E. (author), Fisher, H. (author), Picken, S. (author)The main focus of this Chapter was targeted on novel approaches to compatibility of particles with polymer matrices and detail analysis of rheology-morphology interrelationships. Rather attractive method of mixing based on knowledge of rheological behavior of polymers at high shear rates was proposed and studied. The major fraction of ND around...book chapter 2010
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Brück, E.H. (author), Trung, N.T. (author), Zhang, L. (author), Caron, L. (author), Buschow, K.H.J. (author)The MnCoGe alloy can crystallize in either the hexagonal Ni2In- or the orthorhombic TiNiSi-type of structure. In both phases MnCoGe behaves like a typical ferromagnet with a second-order magnetic phase transition. For MnCoGeBx with B on interstitial positions, we discover a giant magnetocaloric effect associated with a single first-order...journal article 2010
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Trung, N.T. (author), Biharie, V. (author), Zhang, L. (author), Caron, L. (author), Buschow, K.H.J. (author), Brück, E.H. (author)Substitution of some Cr for Mn atoms in MnCoGe was employed to control the magnetic and structural transitions in this alloy to coincide, leading to a single first-order magnetostructural transition from the ferromagnetic to the paramagnetic state with a giant magnetocaloric effect observed near room temperature. Further increase in the Cr...journal article 2010
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Hazelwood, L.A. (author), Walsh, M.C. (author), Pronk, J.T. (author), Daran, J.M. (author)The hop plant, Humulus lupulus L., has an exceptionally high content of secondary metabolites, the hop -acids, which possess a range of beneficial properties, including antiseptic action. Studies performed on the mode of action of hop iso--acids have hitherto been restricted to lactic acid bacteria. The present study investigated molecular...journal article 2009
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Medina, V.G. (author), Almering, M.J.H. (author), Van Maris, A.J.A. (author), Pronk, J.T. (author)In anaerobic cultures of wild-type Saccharomyces cerevisiae, glycerol production is essential to reoxidize NADH produced in biosynthetic processes. Consequently, glycerol is a major by-product during anaerobic production of ethanol by S. cerevisiae, the single largest fermentation process in industrial biotechnology. The present study...journal article 2009
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Hazelwood, L.A. (author), Walsh, M.C. (author), Luttik, M.A.H. (author), Daran-Lapujade, P. (author), Pronk, J.T. (author), Daran, J.M. (author)OA Fund TU Delft Accumulation of glycogen and trehalose in nutrient-limited cultures of Saccharomyces cerevisiae is negatively correlated with the specific growth rate. Additionally, glucose-excess conditions (i.e., growth limitation by nutrients other than glucose) are often implicated in high-level accumulation of these storage carbohydrates....journal article 2009
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Verdoold, J. (author), Tummers, M.J. (author), Hanjali?, K. (author)Based on a detailed experimental investigation in an aspect-ratio-4 rectangular cell in the range 3.7×107?Ra?3.7×109, we present evidence of possible scenarios of the long-term dynamics of large-scale circulations (LSC) in bounded large-aspect-ratio turbulent Rayleigh-Bénard convection. Karhunen-Loève analysis of instantaneous velocity fields...journal article 2009
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Telalovic, S. (author), Ramanathan, A. (author), Mul, G. (author), Hanefeld, U. (author)The three-dimensional sponge-like mesoporous material TUD-1 is straightforward to prepare. Its synthesis can readily be modified to introduce metals into the framework of TUD-1, imparting many different catalytic activities. M-TUD-1 catalysts have proven to be very active, unlimited by diffusion and very stable. By combining two metals into one...journal article 2009
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Männik, J. (author), Driessen, R. (author), Galajda, P. (author), Keymer, J.E. (author), Dekker, C. (author)In many naturally occurring habitats, bacteria live in micrometer-size confined spaces. Although bacterial growth and motility in such constrictions is of great interest to fields as varied as soil microbiology, water purification, and biomedical research, quantitative studies of the effects of confinement on bacteria have been limited. Here, we...journal article 2009
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Vulovic, M. (author), Rieger, B. (author), Van Vliet, L.J. (author), Koster, A.J. (author), Ravelli, R.B.G. (author)Charge-coupled devices (CCD) are nowadays commonly utilized in transmission electron microscopy (TEM) for applications in life sciences. Direct access to digitized images has revolutionized the use of electron microscopy, sparking developments such as automated collection of tomographic data, focal series, random conical tilt pairs and...journal article 2009