TY  - JOUR
A1  - Wüstenhagen, Doreen Anja
A1  - Lukas, Phil
A1  - Müller, Christian
A1  - Aubele, Simone A.
A1  - Hildebrandt, Jan-Peter
A1  - Kubick, Stefan
T1  - Cell-free synthesis of the hirudin variant 1 of the blood-sucking leech Hirudo medicinalis
JF  - Scientific reports
N2  - Synthesis and purification of peptide drugs for medical applications is a challenging task. The leech-derived factor hirudin is in clinical use as an alternative to heparin in anticoagulatory therapies. So far, recombinant hirudin is mainly produced in bacterial or yeast expression systems. We describe the successful development and application of an alternative protocol for the synthesis of active hirudin based on a cell-free protein synthesis approach. Three different cell lysates were compared, and the effects of two different signal peptide sequences on the synthesis of mature hirudin were determined. The combination of K562 cell lysates and the endogenous wild-type signal peptide sequence was most effective. Cell-free synthesized hirudin showed a considerably higher anti-thrombin activity compared to recombinant hirudin produced in bacterial cells.
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-76715-w
SN  - 2045-2322
VL  - 10
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Lonnemann, Jan
A1  - Müller, Christian
A1  - Büttner, Gerhard
A1  - Hasselhorn, Marcus
T1  - The influence of visual-spatial skills on the association between processing of nonsymbolic numerical magnitude and number word sequence skills
JF  - Journal of experimental child psychology
N2  - Nonsymbolic numerical magnitude processing skills are assumed to be fundamental to mathematical learning. Recent findings suggest that visual–spatial skills account for associations between children’s performance in visually presented nonsymbolic numerical magnitude comparison tasks and their performance in visually presented arithmetic tasks. The aim of the current study was to examine whether associations between children’s performance in visually presented tasks assessing nonsymbolic numerical magnitude processing skills and their performance in tasks assessing early mathematical skills, which do not involve visual stimulation, may also be mediated by visual–spatial skills. This line of reasoning is based on the assumption that children make use of mental visualization processes when working on tasks assessing early mathematical skills, such as knowledge of the sequence of number words, even when these tasks do not involve visual stimulation. We assessed 4- to 6-year-old children’s performance in a nonsymbolic numerical magnitude comparison task, in tasks concerning knowledge of the sequence of number words, and in a developmental test to assess visual–spatial skills. Children’s nonsymbolic numerical magnitude processing skills were found to be associated with their number word sequence skills. This association was fully mediated by interindividual differences in visual–spatial skills. The effect size of this mediation effect was small. We assume that the ability to construct mental visualizations constitutes the key factor underlying this mediation effect.
KW  - Approximate number system
KW  - Numerical magnitude processing
KW  - Number word sequence skills
KW  - Visual-spatial skills
KW  - Mental visualization
KW  - Mental number line
Y1  - 2018
U6  - https://doi.org/10.1016/j.jecp.2018.09.018
SN  - 0022-0965
SN  - 1096-0457
VL  - 178
SP  - 184
EP  - 197
PB  - Elsevier
CY  - New York
ER  -