First evidence showing that Pepper vein yellows virus P4 protein is a movement protein.

BACKGROUND: Plant viruses move through plasmodesmata (PD) to infect new cells. To overcome the PD barrier, plant viruses have developed specific protein(s) to guide their genomic RNAs or DNAs to path through the PD. RESULTS: In the present study, we analyzed the function of Pepper vein yellows virus P4 protein. Our bioinformatic analysis using five commonly used algorithms showed that the P4 protein contains an transmembrane domain, encompassing the amino acid residue 117-138. The subcellular localization of P4 protein was found to target PD and form small punctates near walls. The P4 deletion mutant or the substitution mutant constructed by overlap PCR lost their function to produce punctates near the walls inside the fluorescent loci. The P4-YFP fusion was found to move from cell to cell in infiltrated leaves, and P4 could complement Cucumber mosaic virus movement protein deficiency mutant to move between cells. CONCLUSION: Taking together, we consider that the P4 protein is a movement protein of Pepper vein yellows virus.

A novel protein mixture containing vegetable proteins renders enteral nutrition products non-coagulating after in vitro gastric digestion.

BACKGROUND & AIMS: Non-coagulation of protein from enteral nutrition (EN) in the stomach is considered to improve gastric emptying and may result in reduced upper gastrointestinal complications such as reflux and aspiration pneumonia. For the development of a new EN protein mixture with reduced gastric coagulation, the coagulating properties of individual proteins, a novel blend of four proteins (P4 protein blend) and commercial EN products were investigated. METHODS: A semi-dynamic, computer controlled setup was developed to mimic gastric digestion. The coagulation behaviour of 150 ml protein solutions and EN products was investigated. These were heat-treated calcium caseinate, sodium caseinate, whey, soy and pea protein, and the P4 protein blend comprising of the latter four (all solutions 6% w/v protein), four new enteral nutrition product varieties (New Nutrison® .0 or 1.5 kcal/ml, with and without MultiFibre MF6™) based on the P4 protein blend and two other commercially available casein dominant EN products (T1 and T2). RESULTS: Calcium caseinate and sodium caseinate yielded a total wet coagulate of 43.5 ± 0.7 g and 52.7 ± 6.2 g, respectively. Whey, soy, pea and the P4 protein blend did not produce any measurable coagulate. T1 and T2 resulted in a total wet coagulate of 37.5 ± 0.8 g and 57.3 ± 0.8 g, respectively, while all new EN product varieties based on the P4 protein blend did not produce any measurable coagulate. CONCLUSIONS: The P4 protein blend renders EN product varieties non-coagulating after in vitro gastric digestion.