Oral delivery of maize-produced porcine epidemic diarrhea virus spike protein elicits neutralizing antibodies in pigs.

Porcine Epidemic Diarrhea Virus (PEDV) causes severe diarrhea and mortality in piglets. Robust immunity may break the transmission cycle. Expression of antigens in maize grains is a promising method for producing low-cost vaccines.

Co-Administration of Injected and Oral Vaccine Candidates Elicits Improved Immune Responses over Either Route Alone.

Infectious diseases continue to be a significant cause of morbidity and mortality, and although efficacious vaccines are available for many diseases, some parenteral vaccines elicit little or no mucosal antibodies which can be a significant problem since mucosal tissue is the point of entry for 90% of pathogens. In order to provide protection for both serum and mucosal areas, we have tested a combinatorial approach of both parenteral and oral administration of antigens for diseases caused by a viral pathogen, Hepatitis B, and a fungal pathogen, . We demonstrate that co-administration by the parenteral and oral routes is a useful tool to increase the overall immune response.

Maize-Produced Ag2 as a Subunit Vaccine for Valley Fever.

Coccidioides is the causative agent of San Joaquin Valley fever, a fungal disease prevalent in the semiarid regions of the Americas. Efforts to develop a fungal vaccine over the last 2 decades were unsuccessful. A candidate antigen, Antigen 2 (Ag2), is notoriously difficult to express in Escherichia coli, and this study sought to accumulate the antigen at high levels in maize.

Biochemical and biophysical characterization of maize-derived HBsAg for the development of an oral vaccine.

Although a vaccine against hepatitis B virus (HBV) has been available since 1982, it is estimated that 600,000 people die every year due to HBV. An affordable oral vaccine could help alleviate the disease burden and to this end the hepatitis B surface antigen (HBsAg) was expressed in maize. Orally delivered maize material induced the strongest immune response in mice when lipid was extracted by CO2 supercritical fluid extraction (SFE), compared to full fat and hexane-extracted material.

Oral delivery of wafers made from HBsAg-expressing maize germ induces long-term immunological systemic and mucosal responses.

Background: The hepatitis B surface antigen (HBsAg) has been administered over the last 20 years as a parenteral vaccine against the hepatitis B virus (HBV). Despite high seroconversion rates, chronic infection rates are still high worldwide. Orally delivered vaccines provide a practical alternative to injected vaccines, potentially helping poorly responding populations and providing a viable alternative for populations in remote locations.

Supercritical fluid extraction provides an enhancement to the immune response for orally-delivered hepatitis B surface antigen.

The hepatitis B virus continues to be a major pathogen worldwide despite the availability of an effective parenteral vaccine for over 20 years. Orally-delivered subunit vaccines produced in maize may help to alleviate the disease burden by providing a low-cost, heat-stable alternative to the parenteral vaccine. Oral subunit vaccination has been an elusive goal due to the large amounts of antigen required to induce an immunologic response when administered through the digestive tract.

Production of highly concentrated, heat-stable hepatitis B surface antigen in maize.

Plant-based oral vaccines are a promising emergent technology that could help alleviate disease burden worldwide by providing a low-cost, heat-stable, oral alternative to parenterally administered commercial vaccines. Here, we describe high-level accumulation of the hepatitis B surface antigen (HBsAg) at a mean concentration of 0.51%TSP in maize T1 seeds using an improved version of the globulin1 promoter.

Translational regulation of Arabidopsis XIPOTL1 is modulated by phosphocholine levels via the phylogenetically conserved upstream open reading frame 30.

In Arabidopsis thaliana, XIPOTL1 encodes a phosphoethanolamine N-methyltransferase with a central role in phosphatidylcholine biosynthesis via the methylation pathway. To gain further insights into the mechanisms that regulate XIPOTL1 expression, the effect of upstream open reading frame 30 (uORF30) on the translation of the major ORF (mORF) in the presence or absence of endogenous choline (Cho) or phosphocholine (PCho) was analysed in Arabidopsis seedlings. Dose-response assays with Cho or PCho revealed that both metabolites at physiological concentrations are able to induce the translational repression of a mORF located downstream of the intact uORF30, without significantly altering its mRNA levels.

Bioencapsulation of the hepatitis B surface antigen and its use as an effective oral immunogen.

Hepatitis B remains a major global health problem despite the availability of a safe and effective vaccine. Segments of the population lack access to or respond poorly to the parenteral vaccine, perpetuating the infection-transmission cycle. A low cost, orally delivered vaccine has the potential to alleviate many of these problems.

Manipulating corn germplasm to increase recombinant protein accumulation.

Using plants as biofactories for industrial enzymes is a developing technology. The application of this technology to plant biomass conversion for biofuels and biobased products has potential for significantly lowering the cost of these products because of lower enzyme production costs. However, the concentration of the enzymes in plant tissue must be high to realize this goal.

Comparative genomic analysis of novel conserved peptide upstream open reading frames in Drosophila melanogaster and other dipteran species.

Background: Upstream open reading frames (uORFs) are elements found in the 5'-region of an mRNA transcript, capable of regulating protein production of the largest, or major ORF (mORF), and impacting organismal development and growth in fungi, plants, and animals. In Drosophila, approximately 40% of transcripts contain upstream start codons (uAUGs) but there is little evidence that these are translated and affect their associated mORF.

Results: Analyzing 19,389 Drosophila melanogaster transcript annotations and 666,153 dipteran EST sequences we have identified 44 putative conserved peptide uORFs (CPuORFs) in Drosophila melanogaster that show evidence of negative selection, and therefore are likely to be translated.

Identification of novel conserved peptide uORF homology groups in Arabidopsis and rice reveals ancient eukaryotic origin of select groups and preferential association with transcription factor-encoding genes.

Background: Upstream open reading frames (uORFs) can mediate translational control over the largest, or major ORF (mORF) in response to starvation, polyamine concentrations, and sucrose concentrations. One plant uORF with conserved peptide sequences has been shown to exert this control in an amino acid sequence-dependent manner but generally it is not clear what kinds of genes are regulated, or how extensively this mechanism is invoked in a given genome.

Results: By comparing full-length cDNA sequences from Arabidopsis and rice we identified 26 distinct homology groups of conserved peptide uORFs, only three of which have been reported previously.

Adaptive protein evolution and regulatory divergence in Drosophila.

Two recent studies demonstrated a positive correlation between divergence in gene expression and protein sequence in Drosophila. This correlation could be driven by positive selection or variation in functional constraint. To distinguish between these alternatives, we compared patterns of molecular evolution for 1,862 genes with two previously reported estimates of expression divergence in Drosophila.

Evaluating and improving cDNA sequence quality with cQC.

Errors are prevalent in cDNA sequences but the extent to which sequence collections differ in frequencies and types of errors has not been investigated systematically. cDNA quality control, or cQC, was developed to evaluate the quality of cDNA sequence collections and to revise those sequences that differ from a higher quality genomic sequence. After removing rRNA, vector, bacterial insertion sequence and chimeric cDNA contaminants, small-scale nucleotide discrepancies were found in 51% of cDNA sequences from one Arabidopsis cDNA collection, 89% from a second Arabidopsis collection and 75% from a rice collection.