Controlled Release of Growth Factor from Heparin Embedded Poly(aldehyde guluronate) Hydrogels and Its Effect on Vascularization.

To deliver growth factors controllably for tissue regeneration, poly(aldehyde guluronate) (PAG) was obtained from alginate and covalently cross-linked with aminated gelatin (AG) to form PAG/AG hydrogel as a growth factors carrier. The prepared hydrogel exhibits a slow degradation rate and excellent cytocompatibility. Heparin was conjugated with gelatin and embedded into the hydrogel to reserve and stabilize growth factors. Basic fibroblast growth factor (bFGF) was immobilized into the hydrogel and performed sustained release as the hydrogel degraded. The bFGF loaded hydrogel can improve vascularization effectively in a rat dorsal sac model. To summarize, heparin embedded PAG/AG hydrogels would serve as a promising biodegradable vehicle for the controlled delivery of growth factors and promoting vascularization in regenerative medicine.

Sensitive room-temperature phosphorescence for luminometric and visual monitoring of the dynamic evolution of acrylate-vinylidene chloride copolymers.

Unlike fluorescence, room-temperature phosphorescence (RTP) has never been utilized to monitor the dynamic variation of polymer. In the present study, acrylate-vinylidene chloride (VDC) copolymers were doped with a good RTP molecule, N-hydroxyethyl 4-bromo-1,8-naphthalimide (HBN). During the maturation process, marked RTP-intensity enhancement of HBN was observed due to the crystallinity increase of copolymers, verified by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). For ensuring the more efficient RTP emission of HBN, copolymers with a higher content of crystallizable VDC segments and a more polar acrylate comonomer, i.e. methyl acrylate (MA) were preferred. According to the RTP characterizations, the following deductions could be obtained: (1) Maturation for 8-9 days at room temperature was needed for the copolymers with a high VDC content to ensure the complete crystallization; (2) Raising the maturation temperature to 50 and 70 °C not only accelerated the crystallization rate, but also increased the crystallinity of copolymers; (3) RTP method was more sensitive to the slight crystallinity variation than XRD and FTIR. Moreover, the dynamic maturation processes of acrylate-VDC copolymers could be also visually monitored through contacting with certain organic solvents that led to the emission color transition from orange to blue.

Functional analyses unveil the involvement of moso bamboo (Phyllostachys edulis) group I and II NIN-LIKE PROTEINS in nitrate signaling regulation.

For rapid growth, moso bamboo (Phyllostachys edulis) requires large amounts of nutrients. Nitrate is an indispensable molecular signal to regulate nitrogen absorption and assimilation, which are regulated by group III NIN-LIKE PROTEINs (NLPs). However, no Phyllostachys edulis NLP (PeNLP) has been characterized. Here, eight PeNLPs were identified, which showed dynamic expression patterns in bamboo tissues. Nitrate did not affect PeNLP mRNA levels, and PeNLP1, -2, -5, -6, -7, and -8 successfully restored nitrate signaling in Arabidopsis atnlp7-1 protoplasts through recovering AtNiR and AtNRT2.1 expression. Four group I and II PeNLPs (PeNLP1, -2, -5, and -8) interacted with the nitrate-responsive cis-element of PeNiR. Moreover, nitrate triggered the nuclear retention of PeNLP8. PeNLP8 overexpression in Arabidopsis significantly increased the primary root length, lateral root number, leaf area, and dry and wet weight of the transgenic plants, and PeNLP8 expression rescued the root architectural defect phenotype of atnlp7-1 mutants. Interestingly, PeNLP8 overexpression dramatically reduced nitrate content but elevated total amino acid content in Arabidopsis. Overall, the present study unveiled the potential involvement of group I and II NLPs in nitrate signaling regulation and provided genetic resources for engineering plants with high nitrogen use efficiency.

GSK3/shaggy-like kinase 1 ubiquitously regulates cell growth from Arabidopsis to Moso bamboo (Phyllostachys edulis).

Moso bamboo (Phyllostachys edulis) is one of the fastest growing species with a maximum growth rate of 1 m/day. However, the regulator genes for this explosive growth phenomenon have not been functionally studied. Here, we found that Moso bamboo GSK3/shaggy-like kinase 1 (PeGSK1) acts as a negative regulator of cell growth. Over-expression of PeGSK1 in Arabidopsis showed significant growth arrest phenotypes, including dwarfism, small leaves, reduced cell length, and disturbed cell elongation of petiole. Furthermore, Overexpression of PeGSK1 fully inhibited the longer hypocotyl phenotype of Arabidopsis atgsk1 mutants. In addition, PeGSK1-overexpressing lines were resistant to exogenous BR treatment and PeGSK1 interacted with the brassinosteroid signal transduction key regulator BZR1. The BZR1-dependent cell growth genes were down-regulated in PeGSK1-overexpressing lines. These results indicated that PeGSK1 is functionally similar to AtGSK1 and inhibited cell growth via the brassinosteroid signaling pathway. Importantly, PeGSK1 also interacted with PeBZR1, and the expression pattern of PeGSK1 was negatively correlated with the internode elongation of bamboo, indicating that PeGSK1 is involved in the cell growth of bamboo. In summary, our results provide insight into the role of brassinosteroids in the rapid-growth of bamboo culms and identifying target genes for the genetic manipulation of plant height.