Engineering of Corynebacterium glutamicum for the secretory production of recombinant proteins via Tat-dependent pathway

Corynebacterium glutamicum, which has been an industrial producer of various L-amino acids, nucleic acids, and vitamins, is now also regarded as a potential host for the secretory production of recombinant proteins since it exhibits numerous ideal features for protein secretion: (i) it has a single cellular membrane as a gram-positive bacterium, which allows proteins to be easily secreted into the extracellular medium. (ii) C. glutamicum secretes only a few endogenous proteins into the culture medium, which allows the simpler purification of target proteins in downstream process. (iii), secreted proteins from C. glutamicum can be kept stable because extracellular protease activity is rarely detectable. To harness its potential as an industrial platform for recombinant protein production, the development of an efficient secretion system is necessary. To achieve this goal first, we engineered several genetic parts in C. glutamicum: (i) synthetic promoters, (ii) plasmid copy number, (iii) signal peptides, (iv) co-expression of secretion machinery proteins. Using the engineered host-vector systems, gram-scale production of recombinant proteins could be achieved in fed-batch cultivation

Performance Analysis On A Variable Capacity Swash Plate Compressor

A numerical study on the performance of a variable capacity swash plate compressor for an automotive air-conditioning system was carried out. The compressor under investigation had six cylinders and capacity regulation was made by changing the swash plate inclination angle. A numerical simulation program was made based on mathematical modelings on the swash plate dynamics, refrigerant states in various control volumes such as cylinders and crank room, and flows in the opening passages of electric control valve for crank room pressure control. The simulation results such as mass flow rate, compressor power consumption, cooling capacity and COP were compared with measurements within ±5% deviation over various operating conditions except at low operating speed such as idling condition. By using the simulation program, the effect of the crank room pressure on the swash plate inclination angle and the determination of the crank room pressure level by the electric control valve openings could be investigated

A Hybrid Channel Estimation Scheme for OFDM Systems

Accurate channel information is indispensable for coherent reception of OFDM signal. Although a Wienertype channel estimation filter (CEF) is known optimum, it is not easily employable due to large implementation complexity. In practice, a moving average (MA)-type CEF is often employed, but it may not provide robust performance to the variation of channel condition. In this paper, we propose a hybrid CEF that takes advantages of both the Wiener and MA CEF, by alternatively employing the CEF according to the channel condition. Simulation results show that the proposed hybrid CEF scheme provides near optimum performance, while significantly reducing the implementation complexity compared to the long tap Wiener CEF

Transmural Migration of Surgical Sponge Evacuated by Defecation: Mimicking an Intraperitoneal Gossypiboma

The spontaneous defecation of the surpical retained sponge is very rare. Here, we report a case of migrating surgical sponge that was retained in the colon and it was evacuated by defecation

3D garment digitisation for virtual wardrobe using a commodity depth sensor

5-Aminovaleric acid (5AVA) is an important five-carbon platform chemical that can be used for the synthesis of polymers and other chemicals of industrial interest. Enzymatic conversion of L-lysine to 5AVA has been achieved by employing lysine 2-monooxygenase encoded by the davB gene and 5-aminovaleramidase encoded by the davA gene. Additionally, a recombinant Escherichia coli strain expressing the davB and davA genes has been developed for bioconversion of L-lysine to 5AVA. To use glucose and xylose derived from lignocellulosic biomass as substrates, rather than L-lysine as a substrate, we previously examined direct fermentative production of 5AVA from glucose by metabolically engineered E. coli strains. However, the yield and productivity of 5AVA achieved by recombinant E. coli strains remain very low. Thus, Corynebacterium glutamicum, a highly efficient L-lysine producing microorganism, should be useful in the development of direct fermentative production of 5AVA using L-lysine as a precursor for 5AVA. Here, we report the development of metabolically engineered C. glutamicum strains for enhanced fermentative production of 5AVA from glucose.Various expression vectors containing different promoters and origins of replication were examined for optimal expression of Pseudomonas putida davB and davA genes encoding lysine 2-monooxygenase and delta-aminovaleramidase, respectively. Among them, expression of the C. glutamicum codon-optimized davA gene fused with His-Tag at its N-Terminal and the davB gene as an operon under a strong synthetic H promoter (plasmid p36davAB3) in C. glutamicum enabled the most efficient production of 5AVA. Flask culture and fed-batch culture of this strain produced 6.9 and 19.7\ua0g/L (together with 11.9\ua0g/L glutaric acid as major byproduct) of 5AVA, respectively. Homology modeling suggested that endogenous gamma-aminobutyrate aminotransferase encoded by the gabT gene might be responsible for the conversion of 5AVA to glutaric acid in recombinant C. glutamicum. Fed-batch culture of a C. glutamicum gabT mutant-harboring p36davAB3 produced 33.1\ua0g/L 5AVA with much reduced (2.0\ua0g/L) production of glutaric acid.Corynebacterium glutamicum was successfully engineered to produce 5AVA from glucose by optimizing the expression of two key enzymes, lysine 2-monooxygenase and delta-aminovaleramidase. In addition, production of glutaric acid, a major byproduct, was significantly reduced by employing C. glutamicum gabT mutant as a host strain. The metabolically engineered C. glutamicum strains developed in this study should be useful for enhanced fermentative production of the novel C5 platform chemical 5AVA from renewable resources

Whats Happening in the Jury Room? : Analyzing Shadow Jury Deliberations in Korea

This paper looked into the jury deliberation process by examining shadow jury deliberations in 18 actual cases between November 2010 and July 2011 in Korea. Based on the direct observation and the content analysis of the videotaped deliberation, we examined four key areas in jury deliberation in order to gain insights and implications for the institutional design of the jury system: (1) the binding effect of the jury verdict, (2) the number of jurors, (3) the jurors deliberations regarding both conviction and sentencing, and (4) the judges intervention in jury deliberation. The results demonstrate that the shadow jurors in general actively participated in the deliberation process by speaking in turn, and were respectful toward other jurors in debate. The jury forepersons positively played their role by giving jurors equal chance to talk and managed the discussion well. Misunderstanding of law and the intermingling of facts relevant to conviction or sentencing were not as frequent as many people expected: when such problems occurred, they were most often corrected through the intervention of other jurors or judges. Most judges were helpful in jurors reaching a verdict in the jury room. Also there was no definitive relationship between the size of the jury and the quality of deliberation. On the other hand, the shadow jurors tended to state their initial positions early in the deliberation process without fully discussing the issues first. They oftentimes made arguments not based on evidence. In addition, jurors emotions affected decision-making in some instances. Although encouraging aspects as well as areas for improvement coexist, the overall quality of jury deliberation in Korea, as evidenced by this study, is positive. Over time, the Korean jury system is expected to be firmly established as a robust institution to increase democratic participation of the lay people and to enhance the credibility of the judiciary.This article was supported by the 2011 Overseas Research Fund for Humanities and Social Sciences of Seoul National University granted to Professor Jisuk Wo