ABSTRACT
The secretion of recombinant proteins plays an important role in their economic production and purification. The secretion efficiency depends on the responsible signal peptide (SP) in combination with the target protein and the given host and cannot be predicted so far. Due to its high plasmid stability, the lack of alkaline extracellular proteases and only few contaminating extracellular host proteins, Priestia megaterium provides a promising alternative to common Bacillus species. For the development of an easy and fast cloning and screening system to identify the SP best suited to a distinct protein, a plasmid-based SP library containing all predicted 182 Sec-dependent SPs from P. megaterium was established. The splitting of the SPs into 10 groups of individual multi-SP plasmids (pMSPs) allows their grouped amplification and application in screening approaches. The functionality of the whole library was demonstrated by enhancing the amount of the already well-secreted α-amylase AmyE by 1.6-fold. The secretion of a novel penicillin G acylase, which remained as insoluble protein inside the cells, as its native SP is unsuitable for secretion in P. megaterium, could be enhanced even up to 29-fold. Overall, only around 170 recombinant P. megaterium clones based on 50 inserted SPs had to be screened to achieve sufficient amounts for further enzyme characterizations. Thus, this newly developed plasmid-based genetic tool applicable for P. megaterium and also other Bacillus species facilitates the identification of suitable SPs for secretion of recombinant proteins.
ABSTRACT
Single frequency, geometrically symmetric Radio-Frequency (rf) driven atmospheric pressure plasmas exhibit temporally and spatially symmetric patterns of electron heating, and consequently, charged particle densities and fluxes. Using a combination of phase-resolved optical emission spectroscopy and kinetic plasma simulations, we demonstrate that tailored voltage waveforms consisting of multiple rf harmonics induce targeted disruption of these symmetries. This confines the electron heating to small regions of time and space and enables the electron energy distribution function to be tailored.
ABSTRACT
Empathy is an important human ability associated with successful social interaction. It is currently unclear how to optimally measure individual differences in empathic processing. Although the Big Five model of personality is an effective model to explain individual differences in human experience and behavior, its relation to measures of empathy is currently not well understood. Therefore, the present study was designed to investigate the relationship between the Big Five personality concept and two commonly used measures for empathy [Empathy Quotient (EQ), Interpersonal Reactivity Index (IRI)] in four samples from China, Germany, Spain, and the United States of America. This approach was designed to advance the way the Big Five personality model can be used to measure empathy. We found evidence of medium effect sizes for associations between personality and empathy, with agreeableness and conscientiousness as the most important predictors of affective and cognitive empathy (measured by the respective IRI subscales) as well as for a one-dimensional empathy score (measured by the EQ). Empathy in a fictional context was most closely related to openness to experience while personal distress was first of all related to neuroticism. In terms of culture, we did not observe any distinct pattern concerning cultural differences. These results support the cross-cultural applicability of the EQ and the IRI and indicate structurally similar associations between personality and empathy across cultures.
