A morphological analysis of fresh and brine-cured olives attacked by Bactrocera oleae using light microscopy and ESEM-EDS.

The present study investigated the morphology of fresh and brine-cured table olives (TOs) as well as the changes that occur when drupes are attacked by the fruit fly Bactrocera oleae. Morphological analyses were performed using light microscopy (LM) and environmental scanning electron microscopy coupled with energy dispersive spectroscopy (ESEM-EDS). The LM analysis was carried out with visible light to evaluate sections stained with either PAS or Azan mixtures as well as unstained sections observed at fluorescence microscopy. The results of the analyses showed that: i) Azan and PAS staining played a useful complementary role, increasing the information provided by the histological analysis. Indeed, in both fresh and brine-cured TOs, epidermal layers and mesocarpal cells were clearly revealed, including sclereid cells. The histological analysis allowed also to identifying the presence of secoiridoid-biophenols (seco-BPs) in both cell walls and vacuoles, as well as in the drupe regions that had been attacked by fruit flies, where they were found at higher concentrations; ii) in fresh and brine-cured olives, the excitation at 480 nm revealed the distribution of the fluorophores, among which the seco-BP are enclosed; iii) the ESEM-EDS analysis revealed the natural morphology of fresh olives, including the dimensions of their cell layers and the size and depth of the mechanical barriers of suberized or necrotic cells around the larva holes. In addition, the elemental composition of regions of interest of the drupe was determined in fresh and brine-cured TOs. The results highlighted the effectiveness of combined use of LM and ESEM-EDS in order to obtain a picture, as complete as possible, of the structural morphology of TOs. Such analytical combined approach can be used to support multidisciplinary studies aimed at the selection of new cultivars more resistant to fly attack.

Morphological analysis of the seeds of three pseudocereals by using light microscopy and ESEM-EDS.

The seed morphology of three Pseudocereal Grains (PSCg), i.e. quinoa (Chenopodium quinoa Willd, Chenopodiaceae), buckwheat (Fagopyrum esculentum Moench, Polygonaceae) and amaranth (Amaranthus caudatus L., Amaranthaceae) was studied by light microscopy (LM) and Environmental Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (ESEM-EDS). LM was used with visible light to evaluate either unstained sections or sections stained with Azan mixture and with fluorescent light. The aim of the study was to compare the architecture of the three seeds in order to connect their morphology with nutrient localization. The Azan staining allowed for the visualization of the seed coat, the embryo - with its shoot apical meristem - and the radicle cell layers, whereas the use of fluorescent microscopy identified the cells rich in phenolic compounds. Finally, the ESEM-EDS analysis revealed that the seed coat of the quinoa was thinner than that of amaranth or buckwheat. In all PSCg, starch granules appeared to be located in large polygonal cells, surrounded by a thin cell wall. Several globoids of proteins were observed in the embryo cells. In the radicle section, the vascular bundles of the procambium were evident, while Amaranth only showed a consistent layer of calcium crystals, located between the embryo and the perysperm. The morphological differences of the three PSCg were discussed in the context of their structural resistance to processing technologies which impact on nutritional value of derived foods.

Role of MyD88 signaling in the imiquimod-induced mouse model of psoriasis: focus on innate myeloid cells.

Psoriasis is a chronic skin disease associated with deregulated activation of immune cells and keratinocytes. In this study, we used the imiquimod (IMQ)-induced mouse model of psoriasis to dissect better the contribution of hematopoietic and skin-resident stromal cells to psoriasis development. The comparison of disease development in mice carrying the hematopoietic cell-specific deletion of MyD88 (Myd88fl/flVav-cre+ mice) with mice carrying the total MyD88 deficiency (Myd88-/- mice), we show that the progression of skin and systemic inflammation, as well as of epidermal thickening, was completely dependent on MyD88 expression in hematopoietic cells. However, both Myd88-/- mouse strains developed some degree of epidermal thickening during the initial stages of IMQ-induced psoriasis, even in the absence of hematopoietic cell activation and infiltration into the skin, suggesting a contribution of MyD88-independent mechanisms in skin-resident stromal cells. With the use of conditional knockout mouse strains lacking MyD88 in distinct lineages of myeloid cells (Myd88fl/flLysM-cre+ and Myd88fl/flMRP8-cre+ mice), we report that MyD88 signaling in monocytes and Mϕ, but not in neutrophils, plays an important role in disease propagation and exacerbation by modulating their ability to sustain γδ T cell effector functions via IL-1ß and IL-23 production. Overall, these findings add new insights into the specific contribution of skin-resident stromal vs. hematopoietic cells to disease initiation and progression in the IMQ-induced mouse model of psoriasis and uncover a potential novel pathogenic role for monocytes/Mϕ to psoriasis development.