Heterologous production of a ginsenoside saponin (compound K) and its precursors in transgenic tobacco impairs the vegetative and reproductive growth

Planta - Production of compound K (a ginsenoside saponin) and its precursors in transgenic tobacco resulted in stunted growth and seed set failure, which may be caused by strong autotoxicity of...     

Application of recombinant hemagglutinin proteins as alternative antigen standards for pandemic influenza vaccines

Objectives

The single radial immunodiffusion (SRID) assay, used to quantify hemagglutinin (HA) in influenza vaccines, requires reference reagents; however, because centralized production of reference reagents may slow the emergency deployment of vaccines, alternatives are needed.

Results

We investigated the production of HA proteins using recombinant DNA technology, rather than a traditional egg-based production process. The HA proteins were then used in an SRID assay as a reference antigen. We found that HA can be quantified in both egg-based and cell-based influenza vaccines when recombinant HAs (rHAs) are used as the reference antigen. Furthermore, we confirmed that rHAs obtained from strains with pandemic potential, such as H5N1, H7N3, H7N9, and H9N2 strains, can be utilized in the SRID assay. The rHA production process takes just one month, in contrast to the traditional process that takes three to four months.

Conclusions

The use of rHAs may reduce the time required to produce reference reagents and facilitate timely introduction of vaccines during emergencies.

     

Optimum spacing between electrodes in an air-cathode single chamber microbial fuel cell with a low-cost polypropylene separator

Bioprocess and Biosystems Engineering - The performance of a single chamber microbial fuel cell (MFC) with a low-cost polypropylene separator was investigated at various electrode interspaces in a...     

Acetylation of Smc3 by Eco1 is required for S phase sister chromatid cohesion in both human and yeast

Sister chromatid cohesion is normally established in S phase in a process that depends on the cohesion establishment factor Eco1, a conserved acetyltransferase. However, due to the lack of known in vivo substrates, how Eco1 regulates cohesion is not understood. Here we report that yeast Eco1 and its human ortholog, ESCO1, both acetylate Smc3, a component of the cohesin complex that physically holds the sister chromatid together, at two conserved lysine residues. Mutating these lysine residues to a nonacetylatable form leads to increased loss of sister chromatid cohesion and genome instability in both yeast and human. In addition, we clarified that the acetyltransferase activity of Eco1 is essential for its function. Our study thus identified a molecular target for the acetyltransferase Eco1 and revealed that Smc3 acetylation is a conserved mechanism in regulating sister chromatid cohesion.     

Astaxanthin production in transgenicArabidopsis with chyB gene encoding β;-carotene Hydroxylase

Oxycarotenoids, produced through the oxidation of carotenoids, play critical roles in plants. This reaction is mediated by a specific enzyme, β;-carotene hydroxylase, which adds hydroxyl groups to the β;-rings of carotenes. To investigate the effect of the β;-carotene hydroxylase gene (Chyb) on oxycarotenoid biosynthesis, we generated transgenicArabidopsis plants that over-expressedChyb under the control of a 35S promoter. Their levels of zeaxanthin and neoxanthin were two- to three-fold greater relative to the WT, while that of violaxanthin, a final product in the xanlthophyll pathway, was 1.3-fold higher than the control. In contrast, the amount of β;-carotene declined as much as 2.4-fold, depending on the particular transgenic line. Interestingly, astaxanthin was produced in the transgenics, but not in the WT. These data suggest that, with the aid of unknown factors in the host, carotenoids could be converted into metabolites in the astaxanthin biosynthetic pathway. Microarray analysis was used lo identify several genes that were consistently up-or down-regulated in transgenic chyB leaves compared with the controls. Here, we also discuss possible modifications in leaf carotenoids, and the importance of these data from a nutritional standpoint. These authors contributed equally to this work.