The element boron (B) is an essential plant micronutrient, and B deficiency results in significant crop losses worldwide. The maize (Zea mays) tassel-less1 (tls1) mutant has defects in vegetative and inflorescence development, comparable to the effects of B deficiency. Positional cloning revealed that tls1 encodes a protein in the aquaporin family co-orthologous to known B channel proteins in other species. Transport assays show that the TLS1 protein facilitates the movement of B and water into Xenopus laevis oocytes. B content is reduced in tls1 mutants, and application of B rescues the mutant phenotype, indicating that the TLS1 protein facilitates the movement of B in planta. B is required to cross-link the pectic polysaccharide rhamnogalacturonan II (RG-II) in the cell wall, and the percentage of RG-II dimers is reduced in tls1 inflorescences, indicating that the defects may result from altered cell wall properties. Plants heterozygous for both tls1 and rotten ear (rte), the proposed B efflux transporter, exhibit a dosage-dependent defect in inflorescence development under B-limited conditions, indicating that both TLS1 and RTE function in the same biological processes. Together, our data provide evidence that TLS1 is a B transport facilitator in maize, highlighting the importance of B homeostasis in meristem function.

Ratliff BB, Ghaly T, Brudnicki P, Yasuda K, Rajdev M, Bank M, Mares J, Hatzopoulos AK, Goligorsky MS. Endothelial progenitors encapsulated in bioartificial niches are insulated from systemic cytotoxicity and are angiogenesis competent.

Yasuda K, Vasko R, Hayek P, Ratliff B, Bicer H, Mares J, Maruyama S, Bertuglia S, Mascagni P, Goligorsky MS. Functional consequences of inhibiting exocytosis of Weibel-Palade bodies in acute renal ischemia. Am J Physiol Renal Physiol 302: F713-F721, 2012. First published December 7, 2011 doi:10.1152/ajprenal.00541.2011.-Exocytosis of Weibel-Palade bodies (WPB) represents a distinct response of endothelial cells to stressors, and local release of WPB contents leads to systemic escalation of this response. We synthesized a glycine-(N␣-Et)lysine-proline-arginine (ITF 1697) peptide that has a potential to inhibit exocytosis of WPB and protect microcirculation. Here, we confirmed an inhibitory effect of ITF 1697 using intravital videoimaging and point-tracking of individual organelles. In an in vivo study, mice were implanted with Alzet osmotic pumps (10 g ITF 1697·kg Ϫ1 ·min Ϫ1 at volume of 1 l/h) and subjected to renal ischemia (IRI). IRI resulted in marked renal injury and elevation of serum creatinine in mice treated with a vehicle. In contrast, renal injury and elevation of creatinine were significantly ameliorated in mice subjected to IRI and receiving ITF 1697. ITF 1697 prevented a systemic response to IRI: a significant surge in the levels of eotaxin and IL-8 (KC; both components of WPB), IL-1␣, IL-1␤, and RANTES was all prevented or blunted by the administration of ITF 1697, whereas the levels of an anti-inflammatory, IL-10, and macrophage inflammatory protein-1␣ were upregulated in ITF 1697-treated animals. En face staining of aortic endothelial cells showed that WPB were depleted after 40 -180 min post-IRI, and this was significantly blunted in aortic preparations obtained from mice treated with ITF 1697. WPB exocytosis contributed to IRI-associated mobilization of endothelial progenitor cells and hematopoietic stem cells, and ITF 1697 blunted their mobilization. Unexpectedly, 1 mo after IRI, mice treated with ITF 1697 showed a significantly more pronounced degree of scarring than nontreated animals. In conclusion, 1) application of ITF 1697 inhibits exocytosis of WPB and IRI; 2) the systemic inflammatory response of IRI is in part due to the exocytosis of WPB and its blockade blunts it; and 3) ITF 1697 improves short-term renal function after IRI, but not the long-term fibrotic complications.cytokines; chemokines; mobilization of stem cells; fibrosis WEIBEL-PALADE BODIES (WPB) are rod-shaped organelles (0.2 ϫ 2-3 m) characteristic of endothelial cells and containing an array of proteins, peptides, and cytokines, which can be released emergently on demand. Among these biologically active compounds are von Willebrand factor, P-selectin, IL-8, endothelin-1, angiopoietin-2 (Ang-2), and many others, which contribute to the induction of a proinflammatory milieu on the one hand but also induce mobilization of stem cells on the other. A list of compounds known to induce exocytosis of WPB is long and includes thrombin, histamine, peptido-leukotrienes, complement components, superoxide anion, VEGF, sphingosine-1-p...

Biodegradable hydrogels are an important class of biomaterials with a diverse range of applications. In some cases, a rapid hydrogel degradation rate is advantageous. Polycarbonate hydrogels based on dihydroxyacetone (DHA), a natural metabolite, have been reported to undergo surprisingly fast hydrolytic degradation. In the present work, insight into the key features of DHA that contribute to the observed degradation rates is gained. In vitro degradation (mass loss) of three different chemically cross‐linked polycarbonate hydrogels is investigated to shed light on the role of the ketone functional group, as well as the carbon‐chain length between the ketone and carbonate bonds. The ketone is found to be the major cause of rapid degradation. Also, mass loss is accelerated by increased temperature and pH, offering insight into potential tuning parameters and storage conditions. The results show that DHA is a promising monomeric unit for the design of rapidly degrading, biocompatible, and functional biomaterials.