Doped Semiconductor Nanocrystals: Development and Applications

This chapter aims to show significant progress that our group has been developing and the applications of several doped semiconductor nanocrystals (NCs), as nanopowders or embedded in glass systems. Depending on the type of dopant incorporated in the nanocrystals, the physical, chemical, and biological properties can be intensified. However, it can also generate undesired toxic effects that can potentially compromise its use. Here we present the potential of zinc oxide NCs doped with silver (Ag), gold (Au), and magnesium (Mg) ions to control bacterial diseases in agriculture. We have also performed biocompatibility analysis of the pure and Ag-doped sodium titanate (Na2Ti3O7) NCs in Drosophila. The doped nanocrystals embedded in glassy systems are chrome (Cr) or copper (Cu) in ZnTe and Bi2Te3 NCs for spintronic development nanodevices. Therefore, we will show several advantages that doped nanocrystals may present in the technological and biotechnological areas

Transition Metals Doped Nanocrystals: Synthesis, Characterization, and Applications

Doping is a technique that makes it possible to incorporate substitutional ions into the crystalline structure of materials, generating exciting properties. This book chapter will comment on the transition metals (TM) doped nanocrystals (NCs) and how doping and concentration influence applications and biocompatibility. In the NCs doped with TM, there is a strong interaction of sp-d exchange between the NCs’ charge carriers and the unpaired electrons of the MT, generating new and exciting properties. These doped NCs can be nanopowders or be embedded in glass matrices, depending on the application of interest. Therefore, we show the group results of synthesis, characterization, and applications of iron or copper-doped ZnO nanopowders and chromium-doped Bi2S3, nickel-doped ZnTe, and manganese-doped CdTe quantum dots in the glass matrices

Fluorescent Markers: Proteins and Nanocrystals

This book chapter will comment on fluorescent reporter proteins and nanocrystals’ applicability as fluorescent markers. Fluorescent reporter proteins in the Drosophila model system offer a degree of specificity that allows monitoring cellular and biochemical phenomena in vivo, such as autophagy, mitophagy, and changes in the redox state of cells. Titanium dioxide (TiO2) nanocrystals (NCs) have several biological applications and emit in the ultraviolet, with doping of europium ions can be visualized in the red luminescence. Therefore, it is possible to monitor nanocrystals in biological systems using different emission channels. CdSe/CdS magic-sized quantum dots (MSQDs) show high luminescence stability in biological systems and can be bioconjugated with biological molecules. Therefore, this chapter will show exciting results of the group using fluorescent proteins and nanocrystals in biological systems

A Honey Bee Hexamerin, HEX 70a, Is Likely to Play an Intranuclear Role in Developing and Mature Ovarioles and Testioles

Insect hexamerins have long been known as storage proteins that are massively synthesized by the larval fat body and secreted into hemolymph. Following the larval-to-pupal molt, hexamerins are sequestered by the fat body via receptor-mediated endocytosis, broken up, and used as amino acid resources for metamorphosis. In the honey bee, the transcript and protein subunit of a hexamerin, HEX 70a, were also detected in ovaries and testes. Aiming to identify the subcellular localization of HEX 70a in the female and male gonads, we used a specific antibody in whole mount preparations of ovaries and testes for analysis by confocal laser-scanning microscopy. Intranuclear HEX 70a foci were evidenced in germ and somatic cells of ovarioles and testioles of pharate-adult workers and drones, suggesting a regulatory or structural role. Following injection of the thymidine analog EdU we observed co-labeling with HEX 70a in ovariole cell nuclei, inferring possible HEX 70a involvement in cell proliferation. Further support to this hypothesis came from an injection of anti-HEX 70a into newly ecdysed queen pupae where it had a negative effect on ovariole thickening. HEX 70a foci were also detected in ovarioles of egg laying queens, particularly in the nuclei of the highly polyploid nurse cells and in proliferating follicle cells. Additional roles for this storage protein are indicated by the detection of nuclear HEX 70a foci in post-meiotic spermatids and spermatozoa. Taken together, these results imply undescribed roles for HEX 70a in the developing gonads of the honey bee and raise the possibility that other hexamerins may also have tissue specific functions

Neuroprotective effects of oral lamotrigine administration on rabbit retinas after pars plana vitrectomy and silicone oil injection

Purpose: To investigate potential retinal neuroprotective effects of oral lamotrigine in rabbits after pars plana vitrectomy (PPV) and intravitreal silicone oil injection (SOI). Methods: Twelve New Zealand rabbits (weight, 2.0-2.5 kg) underwent PPV with SOI on the right eye. For 30 days postoperatively, 6 rabbits received a daily oral dose of lamotrigine (25 mg/kg), and 6 rabbits received a daily oral dose of water. The animals were killed 30 days after surgery. All retinas were processed histologically, immunostained using glial fibrillary acidic protein (GFAP), and analyzed by fluorescence microscopy. Retina sections from all groups were analyzed by TUNEL for the presence of apoptosis and stained with hematoxylin-eosin for morphologic analysis and retina cell density measurements in each layer using a Zeiss Axiophot microscope and KS 400 software. Results: Retinas from water-operated eyes showed a significant decrease in cell density associated with cell death compared with retinas from water-control eyes; cell density was reduced by 56% in the outer nuclear layer (ONL), 49% in the inner nuclear layer (INL), and 64% in the ganglion cell layer (GCL). Lamotrigine-operated retinas showed a reduction in cell death when compared with water-operated retinas; cell death was reduced by 52% in the ONL, 25% in the INL, and 56% in the GCL. Water-operated retinas showed TUNEL-positive cells and GFAP immunofluorescence throughout Muller cell processes; lamotrigine-operated retinas showed no TUNEL-positive cells and decreased GFAP staining when compared with water-operated retinas. Conclusions: PPV with SOI was associated with apoptosis of retinal cells and activation of glial cells in rabbit eyes. Oral lamotrigine administration provided protection against these effects

Fhos encodes a Drosophila Formin-Like Protein participating in autophagic programmed cell death

Larval tissues undergo programmed cell death (PCD) during Drosophila metamorphosis. PCD is triggered in a stage and tissue-specific fashion in response to ecdysone pulses. The understanding of how ecdysone induces the stage and tissue-specificity of cell death remains obscure. Several steroid-regulated primary response genes have been shown to act as key regulators of cellular responses to ecdysone by inducing a cascade of transcriptional regulation of late responsive genes. In this article, the authors identify Fhos as a gene that is required for Drosophila larval salivary gland destruction. Animals with a P-element mutation in Fhos possess persistent larval salivary glands, and precise excisions of this P-element insertion resulted in reversion of this salivary gland mutant phenotype. Fhos encodes the Drosophila homolog of mammalian Formin Fhos. Fhos is differentially transcribed during development and responds to ecdysone in a method that is similar to other cell death genes. Similarly to what has been shown for its mammalian counterpart, FHOS protein is translocated to the nucleus at later stages of cell death. Fhos mutants posses disrupted actin cytoskeleton dynamics in persistent salivary glands. Together, our data indicate that Fhos is a new ecdysone-regulated gene that is crucial for changes in the actin cytoskeleton during salivary gland elimination in Drosophila. genesis 50:672684, 2012. (c) 2012 Wiley Periodicals, Inc.Sao Paulo State Research CouncilSao Paulo State Research Council [2007/59879-0, 2009/50208-1]Minas Gerais State Research Council [APQ-0047-2]Minas Gerais State Research CouncilFAPESPFAPESPFAPEMIGFAPEMIGCAPES (Federal Research Council)CAPES (Federal Research Council

Effect of HEX 70a depletion on queen ovary growth and worker cuticle formation.

<p>(<b>A</b>) Width of the ovarioles of queens injected with anti-HEX 70a in 0.9% NaCl or saline vehicle only. Measurements were made in two regions of the germarium of 120 ovarioles, 60 of them dissected from 3 anti-HEX 70a injected queens (20 ovarioles per queen), and 60 from 3 control queens. Measurements obtained from bees injected with the antibody, or the antibody vehicle only, were compared using Two-Way ANOVA and the post-hoc Holm-Sidak multiple comparison test (Jandel SigmaStat 3.1 software, Jandel Corporation, San Rafael, CA, USA). (<b>B</b>) Western blot levels of HEX 70a in the hemolymph samples of workers at 4 and 72 h after injection with anti-HEX 70a or saline vehicle only (control). The levels of the ∼200 kDa lipophorin in the same samples were used as loading control. (<b>C</b>) Hind legs of workers injected with anti-HEX 70a in 0.9% NaCl, in comparison to workers injected with mouse IgG in 0,9% NaCl, or those of the 0.9% NaCl injected group.</p

Immunolocalization of HEX 70a in the queen ovariole.

<p>(<b>A</b>) Schematic representation of an ovariole of an egg laying queen (seen at the upper left corner): only the terminal filament, the germarium and early follicles initiating previtellogenic growth in the upper region of the vitellarium are shown in A. Confocal microscopy images: (<b>B</b>) Part of an ovariole showing the middle and lower regions of the vitellarium labeled with rhodamin/phalloidin (green) to highlight F-actin. The arrows and arrowheads show developing nurse cell- and oocyte- chambers, respectively. (<b>C–E</b>) the terminal filament (the lower region is oriented downward) shows HEX 70a foci in the nuclei (D, E) and in cytoplasm (arrows in D, E). (<b>F–H</b>) Nurse cell nuclei in the nurse cell chamber (lower region of the vitellarium as indicated by arrows in B). (<b>I–K</b>) Follicle cell nuclei covering an oocyte at the lower region of the vitellarium (as indicated by arrowheads in B). (<b>C, F, I</b>) DAPI-stained cell nuclei (blue); (<b>D, G, J</b>) anti-HEX 70a/Cy3-staining for HEX 70a detection (red) and (<b>E, H, K</b>) merged images.</p

Detection of HEX 70a in ovarioles of workers at the beginning of the pharate-adult development (∼1 day after pupal ecdysis) (the developmental stage is illustrated at the upper left corner of the figure).

<p>(<b>A</b>) Light microscopy of ovarioles (covered by their respective peritoneal sheath) stained with methylene blue/basic fuchsin. Only the germarium is focused in this figure (the most anterior region of the ovariole, or terminal filament, is not shown). A rosette formed by germline cells (oocyte and nurse cell precursors) is distinguishable (circle) in the germarium. (<b>B, C</b>) Confocal microscopy image of rhodamine/phalloidin labeled F-actin (green) and DAPI-labeled cell nuclei (blue) showing aspects of the structure of the ovarioles (peritoneal sheath removed) at the time they were used for HEX 70A detection. The actin-rich polyfusomes (arrowheads in B) are seen in the center of the cystocyte rosettes in the upper region of the germarium. Ring canals derived from polyfusomes (arrows in B and C) are apparent in the lower region of the germarium shown in B and in higher magnification in C. (<b>D</b>) Confocal microscopy of an ovariole (upper portion of the germarium) stained with DAPI. (<b>E</b>) The same ovariole showing foci of HEX 70a detected with anti-HEX 70a/Cy3 (red). (<b>F</b>) The merged D and E images. The insert in F shows a “control” ovariole (upper portion of the germarium) incubated with the pre-immune serum and subsequently stained with Cy3/DAPI. Arrowheads in D-F show nuclei of germline cells. Arrows in D–F point to nuclei of follicle cell precursors. In all figures, the upper portion of the germarium is oriented upward.</p