Bacterial artificial chromosomes improve recombinant protein production in mammalian cells

<p>Abstract</p> <p>Background</p> <p>The development of appropriate expression vectors for large scale protein production constitutes a critical step in recombinant protein production. The use of conventional expression vectors to obtain cell lines is a cumbersome procedure. Often, stable cell lines produce low protein yields and production is not stable over the time. These problems are due to silencing of randomly integrated expression vectors by the surrounding chromatin. To overcome these chromatin effects, we have employed a Bacterial Artificial Chromosome (BAC) as expression vector to obtain stable cell lines suitable for protein production.</p> <p>Results</p> <p>In this work, we explore the efficacy of a Bacterial Artificial Chromosome based vector applied to production of the constant region of the human IgG1. Direct comparison of bulk HEK 293 cell cultures generated with a "conventional" vector or with a BAC-based vector showed that the BAC-based vector improved the protein yield by a factor of 10. Further analysis of stable cell clones harboring the BAC-based vector showed that the protein production was directly proportional to the number of integrated BAC copies and that the protein production was stable for at least 30 passages.</p> <p>Conclusion</p> <p>Generation of stable cell clones for protein production using Bacterial Artificial Chromosomes offers a clear advantage over the use of conventional vectors. First, protein production is increased by a factor of 10; second, protein production is stable overtime and third, generation of BAC-based expression vectors does not imply a significant amount of work compare to a conventional vector. Therefore, BAC-based vectors may become an attractive tool for protein production.</p

IQ as a moderator of outcome in severity of children's mental health status after treatment in outpatient clinics

Psychotherapy is an effective treatment for mental health disorders, but even with the most efficacious treatment, many patients do not experience improvement. Moderator analysis can identify the conditions under which treatment is effective or whether there are factors that can attenuate the effects of treatment. In this study, linear mixed model analysis was used to examine whether the Full Scale IQ (FSIQ), Performance IQ (PIQ) and Verbal IQ (VIQ) on the Wechsler Intelligence Scale for Children – Third Edition, moderated outcomes in general functioning and symptom load. A total of 132 patients treated at three outpatient child and adolescent mental health services (CAMHS) were assessed at three different time points. The Children’s Global Assessment Scale (CGAS) and the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA) were used to measure the severity of impairments in general functioning and symptom load. IQ was assessed at the start of treatment. Moderator analysis revealed that the FSIQ × time interaction predicted changes in CGAS scores (p < .01), and that the PIQ × time interaction predicted changes in HoNOSCA scores (p < .05). The slopes and intercepts in HoNOSCA scores covaried negatively and significantly (p < .05). The same pattern was not detected for the CGAS scores (p = .08). FISQ and PIQ moderated change in general functioning and symptom load, respectively. This implies that patients with higher IQ scores had a steeper improvement slope than those with lower scores. The patients with the highest initial symptom loads showed the greatest improvement, this pattern was not found in the improvement of general functioning

River hydraulic modeling with ICESat-2 land and water surface elevation

Advances in geodetic altimetry instruments are providing more accurate measurements, thus enabling satellite missions to produce useful data for narrow rivers and streams. Altimetry missions produce spatially dense land and water surface elevation (WSE) measurements in remote areas where in situ data are scarce that can be combined with hydraulic and/or hydrodynamic models to simulate WSE and estimate discharge. In this study, we combine ICESat-2 (Ice, Cloud and land Elevation Satellite) land and water surface elevation measurements with a low-parameterized hydraulic calibration to simulate WSE and discharge without the need for surveyed cross-sectional geometry and a rainfall–runoff model. ICESat-2 provides an opportunity to map river cross-sectional geometry very accurately, with an along-track resolution of 0.7 m, using the ATL03 product. These measurements are combined with the inland water product ATL13 to calibrate a steady-state hydraulic model to retrieve unobserved hydraulic parameters such as river depth or the roughness coefficient. The low-parameterized model, together with the assumption of steady-state hydraulics, enables the application of a global search algorithm for a spatially uniform parameter calibration at a manageable computational cost. The model performance is similar to that reported for highly parameterized models, with a root mean square error (RMSE) of around 0.41 m. With the calibrated model, we can calculate the WSE time series at any chainage point at any time for an available satellite pass within the river reach and estimate discharge from WSE. The discharge estimates are validated with in situ measurements at two available gauging stations. In addition, we use the calibrated parameters in a full hydrodynamic model simulation, resulting in a RMSE of 0.59 m for the entire observation period.</p