Absorption and distribution of root, fruit, and foliar-applied 45 Ca in 'Clemenules' mandarin trees.

BACKGROUND: The mechanisms of calcium (Ca) absorption and transport in plants are still poorly understood. This study focused on assessing the absorption and distribution of Ca in different plant organs after root (soil), foliar, or fruit application to 6-year-old 'Clemenules' mandarin trees, grown in pots, using 45 Ca as a tracer. RESULTS: The rate of 45 Ca absorption and transportation in plant tissues varied according to the treatment method. The fruit and shoot Ca supply led to a rate of 97% to 98% 45 Ca retention in such organs. In Ca-treated fruits, 22% of the applied 45 Ca moved to the pulp and 78% remained in the flavedo and albedo. The fruit peel was examined by scanning electron microscopy and transmission electron microscopy (SEM and TEM) and variations were observed during fruit development. Following 45 Ca soil treatment, approximately 56% of 45 Ca activity was measured in the soil, with 19.5% determined in the roots, 14.6% in the trunks (90% in bark and sapwood and only 10% in heartwood), 9.6% in shoots, and 0.3% in fruits. CONCLUSION: Calcium mobility in 'Clemenules' mandarin trees is limited and depends on the mode of Ca fertilizer application. The distribution of Ca to and within the fruits may be limited during development because of structural and functional constraints. © 2020 Society of Chemical Industry.

Gold nanoparticles as tracking devices to shed light on the role of caveolin-1 in early stages of melanoma metastasis.

AIM: To track early events during lung metastasis, we labeled cells expressing (B16F10CAV1) or lacking CAV1 (B16F10mock) with gold nanoparticles conjugated to the peptide TAT (AuNPs-PEG-TAT). METHODS: B16F10 expressing or lacking CAV1 were labeled with AuNPs-PEG-TAT. The physicochemical properties and cytotoxicity of these nanoparticles, as well as their effects on migration and invasiveness of B16F10 cells in vitro were evaluated. Ex vivo lung distribution of the labeled cells after tail vein injection into C57BL/6 mice was examined. RESULTS: AuNPs-PEG-TAT did not affect B16F10 viability, migration and invasiveness. The metastatic and tumorigenic capability of the labeled B16F10 was also not modified in comparison to unlabeled B16F10 cells. CAV1 expression favored the retention of B16F10 cells in the lungs of mice 2 h post injection, suggesting CAV1 promoted adherence to endothelial cells and transendothelial migration. CONCLUSIONS: We developed a protocol to label B16F10 cells with AuNPs-PEG-TAT that permits subsequent tracking of cells in mice. CAV1 overexpression was found to increase retention and transendothelial migration of B16F10 cells in the lung.

Peptide multifunctionalized gold nanorods decrease toxicity of ß-amyloid peptide in a Caenorhabditis elegans model of Alzheimer's disease.

The properties of nanometric materials make nanotechnology a promising platform for tackling problems of contemporary medicine. In this work, gold nanorods were synthetized and stabilized with polyethylene glycols and modified with two kinds of peptides. The D1 peptide that recognizes toxic aggregates of Aß, a peptide involved in Alzheimer's disease (AD); and the Angiopep 2 that can be used to deliver nanorods to the mammalian central nervous system. The nanoconjugates were characterized using absorption spectrophotometry, dynamic light scattering, and transmission electron microscopy, among other techniques. We determined that the nanoconjugate does not affect neuronal viability; it penetrates the cells, and decreases aggregation of Aß peptide in vitro. We also showed that when we apply our nanosystem to a Caenorhabditis elegans AD model, the toxicity of aggregated Aß peptide is decreased. This work may contribute to the development of therapies for AD based on metallic nanoparticles.