Zein-Based Nanoparticles as Oral Carriers for Insulin Delivery

Zein, the major storage protein from corn, has a GRAS (Generally Regarded as Safe) status and may be easily transformed into nanoparticles, offering significant payloads for protein materials without affecting their stability. In this work, the capability of bare zein nanoparticles (mucoadhesive) and nanoparticles coated with poly(ethylene glycol) (mucus-permeating) was evaluated as oral carriers of insulin (I-NP and I-NP-PEG, respectively). Both nanocarriers displayed sizes of around 270 nm, insulin payloads close to 80 µg/mg and did not induce cytotoxic effects in Caco-2 and HT29-MTX cell lines. In Caenorhabditis elegans, where insulin decreases fat storage, I-NP-PEG induced a higher reduction in the fat content than I-NP and slightly lower than the control (Orlistat). In diabetic rats, nanoparticles induced a potent hypoglycemic effect and achieved an oral bioavailability of 4.2% for I-NP and 10.2% for I-NP-PEG. This superior effect observed for I-NP-PEG would be related to their capability to diffuse through the mucus layer and reach the surface of enterocytes (where insulin would be released), whereas the mucoadhesive I-NP would remain trapped in the mucus, far away from the absorptive epithelium. In summary, PEG-coated zein nanoparticles may be an interesting device for the effective delivery of proteins through the oral route.

Comparative transcriptome and metabolome analyses provide new insights into the molecular mechanisms underlying taproot thickening in Panax notoginseng

Background Taproot thickening is a complex biological process that is dependent on the coordinated expression of genes controlled by both environmental and developmental factors. Panax notoginseng is an important Chinese medicinal herb that is characterized by an enlarged taproot as the main organ of saponin accumulation. However, the molecular mechanisms of taproot enlargement are poorly understood. Results A total of 29,957 differentially expressed genes (DEGs) were identified during the thickening process in the taproots of P. notoginseng. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment revealed that DEGs associated with “plant hormone signal transduction,” “starch and sucrose metabolism,” and “phenylpropanoid biosynthesis” were predominantly enriched. Further analysis identified some critical genes (e.g., RNase-like major storage protein, DA1-related protein, and Starch branching enzyme I) and metabolites (e.g., sucrose, glucose, fructose, malate, and arginine) that potentially control taproot thickening. Several aspects including hormone crosstalk, transcriptional regulation, homeostatic regulation between sugar and starch, and cell wall metabolism, were identified as important for the thickening process in the taproot of P. notoginseng. Conclusion The results provide a molecular regulatory network of taproot thickening in P. notoginseng and facilitate the further characterization of the genes responsible for taproot formation in root medicinal plants or crops.

Comparative transcriptome and metabolome analyses provide new insights into the molecular mechanisms underlying taproot thickening in Panax notoginseng

Background Taproot thickening is a complex biological process and depends on the coordinated expression of the genes controlled by both environmental and developmental factors. Panax notoginseng is an important Chinese medicinal herb characterized by enlarged taproot as the main organ of saponin accumulation. However, little is known about the molecular mechanism of taproot enlargement. Results A total of 29957 DETs were identified during thickening process of P. notoginseng taproot. GO and KEGG pathway enrichment revealed that DETs associated wthith “plant hormone signal transduction”, “starch and sucrose metabolism”, and “phenylpropanoid biosynthesis” were predominantly enriched. Furher functional analysis by integrating DETs expression profiling, endogenous hormone and primary metabolite identified some critical genes (e.g., RNase-like major storage protein, DA1-related protein, Starch branching enzyme I) and primary metabolites (e.g., Sucrose, Glucose, Fructose Malate and Arginine) potentially controlling taproot thickening, and highlighted that hormones crosstalk, transcriptional regulation, homeostasis regulation of sugar and starch, and cell wall metabolism play an important role during thickening process of P. notoginseng taproot. Conclusion These results provide molecular regulatory network of taproot thickening in P. notoginseng and facilitate the characterization of genes responsible for taproot formation in root medicinal plants or crops.

Comparative transcriptome and metabolome analyses provide new insights into the molecular mechanisms underlying taproot thickening in Panax notoginseng

Background Taproot thickening is a complex biological process and depends on the coordinated expression of the genes controlled by both environmental and developmental factors. Panax notoginseng is an important Chinese medicinal herb characterized by enlarged taproot as the main organ of saponin accumulation. However, little is known about the molecular mechanism of taproot enlargement. Results A total of 29957 DETs were identified during thickening process of P. notoginseng taproot. GO and KEGG pathway enrichment revealed that DETs associated wthith “plant hormone signal transduction”, “starch and sucrose metabolism”, and “phenylpropanoid biosynthesis” were predominantly enriched. Furher functional analysis by integrating DETs expression profiling, endogenous hormone and primary metabolite identified some critical genes (e.g., RNase-like major storage protein, DA1-related protein, Starch branching enzyme I) and primary metabolites (e.g., Sucrose, Glucose, Fructose Malate and Arginine) potentially controlling taproot thickening, and highlighted that hormones crosstalk, transcriptional regulation, homeostasis regulation of sugar and starch, and cell wall metabolism play an important role during thickening process of P. notoginseng taproot. Conclusion These results provide molecular regulatory network of taproot thickening in P. notoginseng and facilitate the characterization of genes responsible for taproot formation in root medicinal plants or crops.

Comparative transcriptome and metabolome analyses provide new insights into the molecular mechanism underlying taproot thickening in Panax notoginseng

Background Taproot thickening is a complex biological process and depends on the coordinated expression of the genes controlled by both environmental and developmental factors. Panax notoginseng is an important Chinese medicinal herb characterized by enlarged taproot as the main organ of saponin accumulation. However, little is known about the molecular mechanism of taproot enlargement. Results A total of 29957 DETs were identified during thickening process of P. notoginseng taproot. GO and KEGG pathway enrichment revealed that DETs associated wthith “plant hormone signal transduction”, “starch and sucrose metabolism”, and “phenylpropanoid biosynthesis” were predominantly enriched. Furher functional analysis by integrating DETs expression profiling, endogenous hormone and primary metabolite identified some critical genes (e.g., RNase-like major storage protein, DA1-related protein, Starch branching enzyme I) and primary metabolites (e.g., Sucrose, Glucose, Fructose Malate and Arginine) potentially controlling taproot thickening, and highlighted that hormones crosstalk, transcriptional regulation, homeostasis regulation of sugar and starch, and cell wall metabolism play an important role during thickening process of P. notoginseng taproot. Conclusion These results provide molecular regulatory network of taproot thickening in P. notoginseng and facilitate the characterization of genes responsible for taproot formation in root medicinal plants or crops.

The Major Storage Protein in Potato Tuber Is Mobilized by a Mechanism Dependent on Its Phosphorylation Status

The role of the protein phosphorylation mechanism in the mobilization of vegetative storage proteins (VSPs) is totally unknown. Patatin is the major VSP of the potato (Solanum tuberosum L.) tuber that encompasses multiple differentially phosphorylated isoforms. In this study, temporal changes in the phosphorylation status of patatin isoforms and their involvement in patatin mobilization are investigated using phosphoproteomic methods based on targeted two-dimensional electrophoresis (2-DE). High-resolution 2-DE profiles of patatin isoforms were obtained in four sequential tuber life cycle stages of Kennebec cultivar: endodormancy, bud break, sprouting and plant growth. In-gel multiplex identification of phosphorylated isoforms with Pro-Q Diamond phosphoprotein-specific stain revealed an increase in the number of phosphorylated isoforms after the tuber endodormancy stage. In addition, we found that the phosphorylation status of patatin isoforms significantly changed throughout the tuber life cycle (P < 0.05) using the chemical method of protein dephosphorylation with hydrogen fluoride-pyridine (HF-P) coupled to 2-DE. More specifically, patatin phosphorylation increased by 32% from endodormancy to the tuber sprouting stage and subsequently decreased together with patatin degradation. Patatin isoforms were not randomly mobilized because highly phosphorylated Kuras-isoforms were preferably degraded in comparison to less phosphorylated non-Kuras isoforms. These results lead us to conclude that patatin is mobilized by a mechanism dependent on the phosphorylation status of specific isoforms.

Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces

Biohybrid materials based on the intercalation of zein, the major storage protein in corn, into sodium-exchanged montmorillonite were prepared following two synthesis strategies. The first one made use of zein dissolved in 80% (v/v) ethanol/water solution, the usual solvent for this protein, while the second method is new and uses a sequential process that implies the previous separation of zein components in absolute ethanol. This treatment of zein with ethanol renders a soluble yellow phase and an agglomerate of insoluble components, which are able to intercalate the layered silicate when an aqueous dispersion of montmorillonite is added to the ethanol medium containing both phases. The diverse steps in this second route were investigated individually in order to understand the underlying mechanism that drives to the intercalation of this complex hydrophobic biomacromolecule into the hydrophilic interlayer space of sodium-exchanged montmorillonite. In addition to physicochemical characterization of the resulting materials, these biohybrid interfaces were also evaluated as biofillers in the preparation of diverse ecofriendly nanocomposites.