The use of transmission electron microscopy and oocyte transfer to evaluate in vitro maturation of equine oocytes in different culture conditions

The current study evaluates the ability of equine oocytes matured in different conditions to undergo nuclear and cytoplasmic maturation.. After oocyte transfer, embryonic development was diagnosed at 1.5 and 90 days of gestation. For each group, immature oocytes obtained from slaughterhouse ovaries were matured in vitro (5 replicates). In experiment I, three different media were tested. HTF:BME, SOFaa, and TCM 199. In experiment 11, the HTF:BME was chosen as maturation medium containing pFSH, eFSH, or eFSH + eGH. Nuclear maturation was estimated after stripping the oocytes and staining with Hoechst 33342. The evaluation of cytoplasmic maturation was performed by transmission electron microscopy. For oocyte transfer, six non-cycling recipient mares were used, and 8 to 15 oocytes were transferred in each mare. In experiment I, the results showed no differences (P > .05) in nuclear maturation (MII) among experimental groups. The percentage of MII was 29.3 ( +/- 9.6), 23.4 ( +/- 8.4), and 13.5 ( +/- 12.4) for HTF:BME, SOF, and TCM, respectively. In experiment II, all media tested were efficient in inducing metaphase II. Also, no statistical differences (P > .05) were observed in percentages of nuclear maturation rates when porcine (37.1 +/- 22.4) or equine (25.8 +/- 8.2) FSH were used, or when eFSH + eGH was added to HTF:BME (29.4 +/- 12.3). The analysis of cytoplasmic morphology of oocytes cultured in TCM 199 and SOFaa showed signs of incomplete cytoplasmic maturation and premature cortical reaction. Meanwhile, oocytes cultured in HTF:BME medium presented cytoplasmic characteristics similar to those described by others for in vivo-matured oocytes. The addition of eFSH to the HTF:BME medium resulted in an improvement of cytoplasmic morphology. After oocyte transfer, two mares became pregnant, one from pFSH group and one from eFSH+eGH group. These results indicate that although in vitro matured equine oocytes are capable of fertilization and embryonic development, the percentage of competent oocytes is still low.

Cell enumeration and visualisation by transmission electron microscopy of Lactobacillus rhamnosus treated with cinnamon (Cinnamomum zeylanicum B.) essential oil

The use of essential oils (EOs) in functional foods containing probiotic microorganisms must consider the antimicrobial activity of these oils against beneficial bacteria such as Lactobacillus rhamnosus. This study aimed to evaluate the sensitivity of L. rhamnosus cultures treated with cinnamon EO through viable cell counts and visualisation by transmission electron microscopy. Cinnamon EO at a concentration of 0.04% had a bacteriostatic activity after 2 h of incubation. Although slight alterations were detected in the cell structure, this concentration was considered to be bactericidal, since it led to a significant reduction in cell numbers after 24 h. on the other hand, cinnamon EO at a 1.00% concentration decreased cell counts by 3 log units after 2 h incubation and no viable cell count was detected after 24 h. Transmission electron microscopy indicated that cells treated with 1.00% cinnamon EO were severely damaged and presented cell membrane disruption and cytoplasmic leakage.

Extruded vesicles of dioctadecyldimethylammonium bromide and chloride investigated by light scattering and cryogenic transmission electron microscopy

Combined dynamic and static light scattering (DLS, SLS) and cryogenic transmission electron microscopy (cryo-TEM) were used to investigate extruded cationic vesicles of dioctadecyldimethylammonium chloride and bromide (DODAX, X being Cl- or Br-). In salt-free dispersions the mean hydrodynamic diameter, D-h, and the weight average molecular weight, M-w, are larger for DODAB than for DODAC vesicles, and both D-h and M-w increase with the diameter (phi) of the extrusion filter. NaCl (NaBr) decreases (increases) the DODAB (DODAC) vesicle size, reflecting the general trend of DODAB to assemble as larger vesicles than DODAC. The polydispersity index is lower than 0.25, indicating the dispersions are rather polydisperse. Cryo-TEM micrographs show that the smaller vesicles are spherical while the larger ones are oblong or faceted, and the vesicle samples are fairly polydisperse in size and morphology. They also indicate that the vesicle size increases with phi and DODAB assembles as larger vesicles than DODAC. Lens-shaped vesicles were observed in the extruded preparations. Both light scattering and cryo-TEM indicate that the vesicle size is larger or smaller than phi when phi is smaller or larger than the optimal phi* approximate to 200 nm. (C) 2008 Elsevier B.V. All rights reserved.

A combined experimental and theoretical study on the formation of ag filaments on beta-Ag2MoO4 induced by electron irradiation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Transmission electron microscopy for characterization of acrosomal damage after Percoll gradient centrifugation of cryopreserved bovine spermatozoa

The objective of this study was to characterize acrosomal ultrastructure following discontinuous Percoll gradient centrifugation of cryopreserved bovine sperm. Semen was collected from six bulls of different breeds and three ejaculates per bull were evaluated. Frozen semen samples were thawed and the acrosomal region of sperm cells was evaluated by transmission electron microscopy (TEM) before (n = 18) and after (n = 18) Percoll centrifugation. The evaluation of 20 sperm heads from each of the 36 samples analyzed ensured that a large number of cells were investigated. The data were subjected to analysis of variance at a level of significance of 5%. Percoll centrifugation reduced the percentage of sperm exhibiting normal acrosomes (from 61.77 to 30.24%), reduced the percentage of sperm presenting atypical acrosome reactions (from 28.38 to 4.84%) and increased the percentage of sperm exhibiting damage in the acrosome (from 6.14 to 64.26%). The percentage of sperm with typical acrosome reactions was not significantly different before (3.70%) and after (0.67%) centrifugation. TEM distinguished four different types of acrosomal status and enabled ultrastructural characterization of acrosomal injuries. The percentage of sperm exhibiting normal acrosomes decreased and damage in the acrosome was the most frequent acrosomal injury with the Percoll gradient centrifugation protocol utilized.

Testicular structure and description of the seminal pathway in Leporinus macrocephalus (Anostomidae, Teleostei)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Toward an understanding of intermediate- and short-range defects in ZnO single crystals. A combined experimental and theoretical study

A joint use of experimental and theoretical techniques allows us to understand the key role of intermediate- and short-range defects in the structural and electronic properties of ZnO single crystals obtained by means of both conventional hydrothermal and microwave-hydrothermal synthesis methods. X-ray diffraction, Raman spectra, photoluminescence, scanning electronic and transmission electron microscopies were used to characterize the thermal properties, crystalline and optical features of the obtained nano and microwires ZnO structures. In addition, these properties were further investigated by means of two periodic models, crystalline and disordered ZnO wurtzite structure, and first principles calculations based on density functional theory at the B3LYP level. The theoretical results indicate that the key factor controlling the electronic behavior can be associated with a symmetry breaking process, creating localized electronic levels above the valence band.

Structural and morphological characteristics of (Pb1-x Sr (x) )TiO3 powders obtained by polymeric precursor method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ontogenesis, structure and ultrastructure of Hymenaea stigonocarpa (Fabaceae : Caesalpinioideae) colleters

The genus Hymenaea is characterized by a great diversity of secretory structures, but there are no reports of colleters yet. The objectives of this study are to report the occurrence and describe the origin and structure of colleters in Hymenaea stigonocarpa Mart. ex Hayne. Shoot apex samples were collected, fixed, and processed for light microscopy, scanning electron microscopy, and transmission electron microscopy as per usual methods. Colleters occur predominantly on the stipule's adaxial side. These structures are found at the base on a narrow strip, corresponding to the median vein up to half the length of the stipule. When present on the abaxial side, they are concentrated at the base and restricted to the margins. Colleters develop from the protoderm; they are elongate and club-shaped. Their body has no stratification; their surface cells differ from the inner cells only in position and presence of cuticle. Colleter cells have thin walls, dense cytoplasm, large nuclei, many mitochondria, rough endoplasmic reticulum, and abundant dictyosomes. Histochemical tests with Ruthenium red showed pectic compounds in the cytosol. In H. stigonocarpa, colleter arrangement is compatible with the hypothesis that they protect shoot apex. In this species, protection is reinforced by the sheath formed by the stipule pairs.

Salivary glands of Amblyomma cajennense (Acari: Ixodidae): a histological and an ultrastructural overview

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Hydrothermal Synthesis Conditions and Device Configuration on the Photoresponse of UV Sensors Based on ZnO Nanorods

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of oxygen atmosphere on crystallization and properties of LiNbO3 thin films

Thin films of lithium niobate were deposited on the Pt/Ti/SiO2 (111) substrates by spin coating from the polymeric precursor method (Pechini process). Annealing in static air and oxygen atmosphere was performed at 500 degreesC for 3 h. The films obtained were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The dielectric constant and dissipation factor were measured in frequency region from 10 Hz to 10 MHz. Electrical characterization of the films pointed to ferroelectricity via hysteresis loop. The influence of oxygen atmosphere on crystallization, morphology and properties of LiNbO3 thin films is discussed. (C) 2003 Elsevier Ltd. All rights reserved.

Growth mechanism of octahedron-like BaMoO4 microcrystals processed in microwave-hydrothermal: Experimental observations and computational modeling

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Experimental paracoccidioidomycosis in hamster: transmission electron microscopy of inoculation site lesion

Estudou-se sequencialmente, à microscopia eletrônica de transmissão, a interação entre Paracoccidioides brasiliensis (Pb) e células inflamatórias em hamsters inoculados por via intratesticular. Seis horas após inoculações havia predominância de neutrófilos, estando presentes algumas células mononucleares e eosinófilos. Os neutrófilos foram progressivamente substituídos por células mononucleares. Fungos viáveis apresentavam-se fagocitados ou circunscritos por células inflamatórias, geralmente com ampla interface hospedeiro-parasita. Fungos mortos ou degenerados eram acompanhados de interfase estreita. A camada externa da parede do Pb era às vezes quebrada quando em contacto com neutrófilos, em vários pontos, sendo os fragmentos dessa parede descamados e fagocitados. Células fúngicas pequenas com um único núcleo se relacionavam com ampla interfase enquanto as células maiores e multinucleadas apresentavam paredes irregulares, por vezes, contendo lomasoma e/ou estrutura semelhante à mielina. Diferentes padrões de interação do Pb com células do hospedeiro podem ser decorrentes do a fluxo de células inflamatórias funcionalmente diferentes ao local de inoculação ou à idade dos fungos ou ambos os fatores.

Synthesis and sintering of ZrO2-CeO2 powder by use of polymeric precursor based on Pechini process

Nanocrystalline ZrO2-12 mol % CeO2 powders were synthesized using a polymeric precursor method based on the Pechini process. X-ray diffraction (XRD) patterns showed that the method was effective to synthesize tetragonal zirconia single-phase. The mean crystallite size attained ranges from 6 to 15 nm. The BET surface areas were relatively high reaching 97 m(2)/g. Studies by nitrogen adsorption/desorption on powders, dilatometry of the compacts, and transmission electron microscopy (TEM) of the powders, were also developed to verify the particles agglomeration state. Both citric acid : ethylene glycol ratio and calcination temperature affected the powder morphology, which influenced the sinterability and microstructure of the sintered material, as showed by scanning electron microscopy (SEM). (C) 2001 Kluwer Academic Publishers.