Molecular characterization of the sdaCB operon in Escherichia coli K-12

Focuses on the molecular aspects of the sdaCB gene, its structure, and its regulation

Decreased Information Replacement of Working Memory After Sleep Deprivation: Evidence From an Event-Related Potential Study

Working memory (WM) components are altered after total sleep deprivation (TSD), both with respect to information replacement and result judgment. However, the electrophysiological mechanisms of WM alterations following sleep restriction remain largely unknown. To identify such mechanisms, event-related potentials were recorded during the n-back WM task, before and after 36 h sleep deprivation. Thirty-one young volunteers participated in this study and performed a two-back WM task with simultaneous electroencephalography (EEG) recording before and after TSD and after 8 h time in bed for recovery (TIBR). Repeated measures analysis of variance revealed that, compared to resting wakefulness, sleep deprivation induced a decrease in the P200 amplitude and induced longer reaction times. ERP-component scalp topographies results indicated that such decrease primarily occurred in the frontal cortex. The N200 and P300 amplitudes also decreased after TSD. Our results suggest that decreased information replacement of WM occurs after 36 h of TSD and that 8 h TIBR after a long period of TSD leads to partial restoration of WM functions. The present findings represent the EEG profile of WM during mental fatigue

Optimization and scale-up of cell culture and purification processes for production of an adenovirus-vectored tuberculosis vaccine candidate

Tuberculosis (TB) is the second leading cause of death by infectious disease worldwide. The only available TB vaccine is the Bacille Calmette-Guerin (BCG). However, parenterally administered Mycobacterium bovis BCG vaccine confers only limited immune protection from pulmonary tuberculosis in humans. There is a need for developing effective boosting vaccination strategies. AdAg85A, an adenoviral vector expressing the mycobacterial protein Ag85A, is a new tuberculosis vaccine candidate, and has shown promising results in pre-clinical studies and phase I trial. This adenovirus vectored vaccine is produced using HEK 293 cell culture. Here we report on the optimization of cell culture conditions, scale-up of production and purification of the AdAg85A at different scales. Four commercial serum-free media were evaluated under various conditions for supporting the growth of HEK293 cell and production of AdAg85A. A culturing strategy was employed to take advantages of two culture media with respective strengths in supporting the cell growth and virus production, which enabled to maintain virus productivity at higher cell densities and resulted in more than two folds of increases in culture titer. The production of AdAg85A was successfully scaled up and validated at 60L bioreactor under the optimal conditions. The AdAg85A generated from the 3L and 60L bioreactor runs was purified through several purification steps. More than 98% of total cellular proteins was removed, over 60% of viral particles was recovered after the purification process, and purity of AdAg85A was similar to that of the ATCC VR-1516 Ad5 standard. Vaccination of mice with the purified AdAg85A demonstrated a very good level of Ag85A-specific antibody responses. The optimized production and purification conditions were transferred to a GMP facility for manufacturing of AdAg85A for generation of clinical grade material to support clinical trials

Treatment of saline organic wastewater by heterogeneous catalytic ozonation with Al2O3-PEC-CaxOy as catalysts

Al2O3-Pectin-CaxOy (Al2O3-PEC-CaxOy) was prepared as catalysts to improve the treatment of saline organic wastewater with heterogeneous catalytic ozonation. Compared with ozonation alone (33%), the removal rate of COD (62%) was significantly increased for Al2O3-PEC-CaxOy catalysts prepared under the optimized conditions. The introduction of pectin made Ca2+ firmly loaded on the support, and avoided the loss of active sites in the process of catalytic oxidation. In addition, the formation of porous carbon layer on the surface of the Al2O3 support after pectin calcination was conducive to improving the catalytic activity of the catalyst. Electron paramagnetic resonance (EPR) and radical quenching experiments showed that hydroxyl radical (•OH), superoxide radical (•O2−) and singlet oxygen (1O2) were the reactive oxygen species (ROS) that attributed to the organic matter removal. Both free radical and non-free radical pathways were involved in the degradation of organic pollutants during the catalytic ozonation process. The removal rate of COD was only decreased slightly after twenty times of continuous operation for Al2O3-PEC-CaxOy catalysts, indicating that Al2O3-PEC-CaxOy catalysts with the good catalytic stability and reusability. It showed a great significance for long-term practical application with the economical and effective performances

Expression System for High Levels of GAG Lyase Gene Expression and Study of the hepA Upstream Region in Flavobacterium heparinum

A system for high-level expression of heparinase I, heparinase II, heparinase III, chondroitinase AC, and chondroitinase B in Flavobacterium heparinum is described. hepA, along with its regulatory region, as well as hepB, hepC, cslA, and cslB, cloned downstream of the hepA regulatory region, was integrated in the chromosome to yield stable transconjugant strains. The level of heparinase I and II expression from the transconjugant strains was approximately fivefold higher, while heparinase III expression was 10-fold higher than in wild-type F. heparinum grown in heparin-only medium. The chondroitinase AC and B transconjugant strains, grown in heparin-only medium, yielded 20- and 13-fold increases, respectively, in chondroitinase AC and B expression, compared to wild-type F. heparinum grown in chondroitin sulfate A-only medium. The hepA upstream region was also studied using cslA as a reporter gene, and the transcriptional start site was determined to be 26 bp upstream of the start codon in the chondroitinase AC transconjugant strain. The transcriptional start sites were determined for hepA in both the wild-type F. heparinum and heparinase I transconjugant strains and were shown to be the same as in the chondroitinase AC transconjugant strain. The five GAG lyases were purified from these transconjugant strains and shown to be identical to their wild-type counterparts

IFN-α armed gE elicits superior immunogenicity compared to unmodified antigens and flagellin armed gE in mice

Herpes zoster (HZ) induces significant pain and discomfort, which can seriously affect the quality of life of patients. At present, there is no specific treatment for HZ, and the mosteffective HZ control is vaccination. The main obstacle to developing an effective HZ vaccine is poorly induced cellular immune response. In this study, the IFN-α–gE–Fc fusion protein induced higher levels of humoral and cellular immunity compared to the unengineered gE antigen and higher levels of cellular immunity compared to the flagellin–gE–Fc fusion protein in a murine model. Compared with the marketed recombinant herpes zoster vaccine (Shingrix), IFN-α–gE–Fc can replace current used MPL adjuvant. At the same time, the immunogenicity of the IFN-α–gE–Fc + AQ was not weaker than that of the marketed recombinant zoster vaccine. The novel fusion protein provides a candidate entity for the development of a safe and effective novel HZ vaccine

Experimental schema and plan.

<p>Depicting the timelines of vaccination (BCG priming at wk0 and AdHu5Ag85A boosting at wk14), <i>M</i>.<i>tb</i> infectious challenge (wk20) and fixed endpoint/autopsy (wk38). Scheduled times for clinical signs, blood work for acute phase protein measurement, chest X-ray and immune monitoring are indicated. Timelines during infection phase are referred relative to the 18 weeks post-challenge timepoint (indicated within parentheses).</p