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Search Results: 1 - 10 of 817 matches for " ultrastructure "
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Observation on Poterioochromonas sp. (Chrysophyte)  [PDF]
Shengjuan Guo, Lirong Song
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.26068
Abstract: Poterrioochromonas sp., isolated from Microcystis cultures in 2002, was described with LM, SEM, TEM. The grazing characteristics of this strain were also observed in laboratory experiments. The results showed that this strain has the representative features of the genus except for the lorica, and the most conspicuous feature of Poterioochromonas sp. was about the chromatophores.
Buspirone Ameliorates the Morphine Withdrawal-Induced Anxiety through Synaptic Ultrastructural Changes in Hippocampus of Rat  [PDF]
Jialin Gao, Gang Qian, Suyuan Luo, Yan Tian, Mingsong Wu, Zhongxiang Yao
Psychology (PSYCH) , 2013, DOI: 10.4236/psych.2013.410A003
Abstract:

Morphine administration causes long-lasting neural changes in the brain that underpin the behavioral abnormalities, and the relationship between structural changes and behavioral symptoms is obscure. In present study, the elevated plus-maze and transmission electron microscope were applied to validate the anxiety-like behaviors and synaptic ultrastructural changes in the hippocampi of rats among the morphine group (morphine administration only), the buspirone group (morphine plus buspirone administration) and the vehicle (saline treated only). As compared with the vehicle group, lower values of OE (times of entering into the open arms), OE% (percentage of entries into the open arms), OT (time spent in the open arms), OT% (percentage of time stayed in the open arms), Ns (surface density (Sv)/numerical density (Nv)) and S (surface area) of synapses were observed in the morphine group , but significantly, behavior higher scores of RR (rearing), HD (head-dipping), FBA (flat back approach), and higher Nv, Sv, PSD (postsynaptic density), LPT (length of postsynaptic thickening), WCJ (widths in synaptic cleft on junctions) and CCR (curvature of the cleft region) of synapses appeared in the morphine group. However, no significant differences in values of most of those parameters above were detected between the vehicle group and the buspirone group. These results supported that anxiety-like symptoms of rats significantly occurred to the rats after acute morphine withdrawal, but buspirone administration could reverse these indexes. It also proved that the appearance/disappearance of anxiety-related symptoms was related to the ultrastructural changes/reversibility of synapses in the hippocampus with morphine and buspirone administrations. So, it suggested that anxiety-related symptoms were modified in rats subjected to the synaptic ultrastructural changes in hippocampus by morphine acute withdrawal and were further rehabilitated by buspirone administration. It is helpful to pursue the effective therapeutic methods of morphine addiction.

Cytochemical, Structural and Ultrastructural Characterization of Tetrasporogenesis in Bostrychia radicans (Ceramiales, Rhodophyta) from the Mangroves of Itacorubi and Rio Ratones, Santa Catarina, Brazil  [PDF]
Ticiane Rover, Carmen Simioni, Luciane Cristina Ouriques, Zenilda Laurita Bouzon
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.614242
Abstract: Little is known about the morphology and location of macromolecules, especially proteins and carbohydrates, in vegetative and reproductive structures of mangrove species, including Bostrychia radicans. Therefore, to gain a better understanding of tetrasporogenesis in B. radicans, cytochemical, structural and ultrastructual analyses were performed. Thalli were collected from mangroves in Florianópolis, Santa Catarina, Brazil. Fertile branches were fixed and processed for light microscopy (LM), confocal microcopy and transmission electron microscopy (TEM) observations. The LM sections were stained with toluidine blue, periodic acid-Schiff and Coomassie brilliant blue. Tetrasporogenesis occurs in the pericentral cells of the terminal branches. This process is initially characterized by an increase in cell volume, resulting from the proliferation of organelles. The young tetrasporangia remain connected to the basal cell by pit connections. After a considerable increase in volume, the tetrasporocytes divide tetrahedrally, giving rise to haploid spores. During this process, there is an increasing production of starch grains, causing the organelles to group. As the organelles proliferate, the plasma membrane undergoes simultaneous invaginations toward the tetrasporangium center. The most conspicuous organelle throughout tetrasporogenesis was the Golgi complex. Polysaccharidic components are predominant in the tetrasporangium cell wall throughout tetrasporogenesis. Although protein components prevail in the cytoplasm of younger tetrasporangia, there is a predominance of reserve material with maturation. In the initial phase, there is an increase in the number of chloroplasts and a significant increment of Golgi bodies which contribute to the formation of the amorphous portion of the cell wall and possibly the biosynthesis of starch grains.
Spermiogenesis and spermatozoa ultrastructure in five species of the Curimatidae with some considerations on spermatozoal ultrastructure in the Characiformes
Quagio-Grassiotto, Irani;Gameiro, Maria Carolina;Schneider, Tatiana;Malabarba, Luiz Roberto;Oliveira, Claudio;
Neotropical Ichthyology , 2003, DOI: 10.1590/S1679-62252003000100004
Abstract: spermiogenesis in the curimatid species, steindachnerina insculpta, cyphocharax gillii, c. modestus, c. spilotus, and potamorhina altamazonica, is characterized by lateral development of the flagellum, nuclear rotation, eccentric nuclear fossa formation, and chromatin compacted into thick fibers. these spermatozoa exhibit a spherical head containing a nucleus with the chromatin highly condensed into thick fibers with small electron-lucent areas, and no acrosome. the nuclear fossa is of the moderate type and eccentric and penetrated by the centriolar complex. the midpiece is small, has many elongate vesicles, and a short cytoplasmic channel. mitochondria may be elongate, branched or c-shaped, and are separated from the initial segment of the axoneme by the cytoplasmic channel. the flagellum contains the classical axoneme structure (9+2) and has a membranous compartment in the initial region; it does not have lateral fins. only small differences were observed among the analyzed species and genera of the curimatidae. spermiogenesis and spermatozoa in the curimatidae have many of the characteristics found in almost all other characiform species. on the other hand, the presence of a membranous compartment in the initial region of curimatid flagella, a structure common in many cypriniformes spermatozoa, is unknown in other characiforms. spermiogenesis and the spermatozoa of the characiformes are discussed.
Análisis Morfométrico del Efecto del Láser Infrarrojo sobre Hepatocitos de Rata
Cornejo,R; Matamala,F; Silva,H; Garrido,O;
International Journal of Morphology , 2009, DOI: 10.4067/S0717-95022009000300031
Abstract: the infrared lasser emitted by the gallium arsenide diode provides an adequate therapy for articular lessions due to their healing, analgesic, and anti-inflammatory powers. it also promotes at cellular level mitochondrial atp synthesis, modulates calcium channels and activate mitotic processes by increasing dna and protein synthesis. to determine the effective doses which stimulates rat liver protein synthesis, several samples from normal and irradiated tissues to intensities of 1, 2, 4, 8, and 16 joules/cm2 by 15 consecutive days were taken. these samples were later prepared and observed under transmission e.m. (10000x) and analyzed by morphometric studies, where volume and organelle distribution, such as nucleus, cytoplasm, endoplasmic reticulum, glycogen inclussions, nucleolus, eu and heterochromatin were accounted, together at nuclear-cytoplasmic relationships and the cellular and nuclear areas. under comparison normal and irradiated hepatocytes presented a significative difference in all evaluated parameters. it can be concluded that at certain specific level of infrared irradiation, hepatocytes alter their morphology by modifyng those cellular components involved in protein síntesis.
Aspectos ultra-estruturais das vilosidades intestinais após o clampeamento do pedículo hepático de ratos
Camargo, Lázaro Manoel de;Evêncio Neto, Joaquim;Freitas, Silvio Henrique de;Sim?es, Manuel de Jesus;Gomes, Paulo de Oliveira;Sébe, Abr?o Ant?nio;
Acta Cirurgica Brasileira , 2003, DOI: 10.1590/S0102-86502003000600005
Abstract: purpose: to study the ultrastructural of rat intestinal villi (ileum) after total hepatic pedicle clumping for different period of time. methods: forty male rats were divided into four groups of ten animals each. the sham group was not being submitted to ischemia (control). e1, e2 and e3 group were submitted to 10, 20 and 30 minutes of ischemia, respectively. at the end of the experiment fragments of the ileum were taken off and examined by electromicroscope. results: leucocyte infiltration, vascular dilation and electrotransparent areas were observed in intestinal villi of lamina propria of e1 and e2 groups. in reference to group e3 desquamation of epithelial layer, desquamation of intestinal villi and signs of apoptosis were observed. hemorrhagic areas, dilated lymphatics and blood vessels and lots of leucocytes were observed in lamina propria. conclusion: the clumping of hepatic pedicle provokes esplacnic congestion, time dependent, and to the 30 minutes were epithelial cell desquamation, apoptosis signs and hemorrhage.
Algunas consideraciones sobre la patología ultraestructural de los queratinocitos en leucoplasia bucal del tipo clínico homogéneo
Cede?o B,Floribel; Finol,Héctor J;
Acta Odontológica Venezolana , 2005,
Abstract: oral leukoplakia is a predominantly white lesion non characterized as any other established definite lesion. it constitutes a potentially malignant lesion, with a transformation rate that varies between 3 and 18%. clinically, there are homogeneous and non homogeneous leukoplakia. homogeneous leukoplakia is related with a minor transformation potential. however, the ultrastructural study of these lesions could reveal initial morphological changes as malignancy markers not detected by histopathological studies. in this study 5 biopsies of oral leukoplakia were taken from patients attending in the service of estomatological clinics, dental school, universidad central de venezuela. samples were processed by routine techniques for transmission electron microscopy. results were as follows: disruptions and lamination of basement membrane, decrease of desmosome member and widening of intercellular spaces. keratinocytes showed variations in number and distribution of tonofilaments, elongated nuclei with variable amount of heterochromatin, some showing scarce heterochomatin other exhibiting condensed areas of it. nuclei presented more than one nucleolus with reticular aspect. in general keratinocyte cytoplasm showed proliferation of organelles. mentioned alterations suggest abnormalities in the organizational plan of ripeness of keratinocytes indicating metabolic and proliferative activities similar to these observed in oral carcinomas.
Patología Ultraestructural de la lesión Leucoplásica: Reporte de un caso
Cede?o,Floribel; Finol,Héctor J; Bravo,Inés M; Gonzalez,Néllida; Bello,Beatriz;
Acta Odontológica Venezolana , 2001,
Abstract: observation of biopsy from a male 49 years patient with oral leucoplakia showed alteration of keratinocytes, variation in the number of desmosome and an evident spongiosis. changes of keratinocytes including an increment of polysomes, presence of pyknotic nucleus and variable nucleolus structure have been related to the malignancy potential of oral leukoplakia lesions.
Palynological analysis of Sphaeropteris gardneri (Cyatheaceae, Pteridophyta)
Marquez, Gonzalo J.;Morbelli, Marta A.;Giudice, Gabriela E.;
Anais da Academia Brasileira de Ciências , 2010, DOI: 10.1590/S0001-37652010000200012
Abstract: the spore morphology and wall ultrastructure of sphaeropteris gardneri (hook.) r.m. tryon from brazil were analyzed with lm, sem and tem. the spores are trilete with an ornamentation formed of short low ridges with spines in their margins. the exospore is 2.5μm thick, two- layered in section and single or branched channels are present. the perispore is 1.2μm thick and two-layered. the inner layer has three strata: the inner stratum is formed of a network of branched and fused threads, the middle stratum has threads with a radial orientation and in the outer stratum thin, dark fibres are immersed in a less dense contrasted matrix. the outer layer of the perispore is the one that forms the echinate-ridges and is constituted of threads arranged in a compact way. globules of different sizes are observed on the surface. the differences found in the perispore ornamentation and ultrastructure in alsophila, which was previously studied, and those of sphaeropteris, show a tendency to wall complexity.
Leishmania (Viannia) lainsoni: occurrence of intracellular promastigote forms in vivo and in vitro
Corrêa, José R;Soares, Maurilio J;
Memórias do Instituto Oswaldo Cruz , 2006, DOI: 10.1590/S0074-02762006000800016
Abstract: experimental chronic (45-day-old) skin lesion in hamster hind foot induced by leishmania (viannia) lainsoni infection showed the presence of promastigote forms in the tissue, inside parasitophorous vacuoles, as assessed by transmission electron microscopy. experimental in vitro interaction (24 and 48 h) between leishmania (v.)lainsoni and j774-g8 macrophage cells also demonstrated the same profile. this morphological aspect is unusual, since in this parasite genus only amastigote forms have been described as the resistant and obligate intracellular forms.
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