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Artigos de revistas sobre o tema "Ultrastructure (Biology)"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 1 de agosto de 2024

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1

Montanaro, Jacqueline, Daniela Gruber e Nikolaus Leisch. "Improved ultrastructure of marine invertebrates using non-toxic buffers". PeerJ 4 (31 de março de 2016): e1860. http://dx.doi.org/10.7717/peerj.1860.

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Many marine biology studies depend on field work on ships or remote sampling locations where sophisticated sample preservation techniques (e.g., high-pressure freezing) are often limited or unavailable. Our aim was to optimize the ultrastructural preservation of marine invertebrates, especially when working in the field. To achieve chemically-fixed material of the highest quality, we compared the resulting ultrastructure of gill tissue of the musselMytilus eduliswhen fixed with differently buffered EM fixatives for marine specimens (seawater, cacodylate and phosphate buffer) and a new fixative formulation with the non-toxic PHEM buffer (PIPES, HEPES, EGTA and MgCl2). All buffers were adapted for immersion fixation to form an isotonic fixative in combination with 2.5% glutaraldehyde. We showed that PHEM buffer based fixatives resulted in equal or better ultrastructure preservation when directly compared to routine standard fixatives. These results were also reproducible when extending the PHEM buffered fixative to the fixation of additional different marine invertebrate species, which also displayed excellent ultrastructural detail. We highly recommend the usage of PHEM-buffered fixation for the fixation of marine invertebrates.

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2

Neuhaus, B. "Ultrastructure, Biology, and Phylogenetic Relationships of Kinorhyncha". Integrative and Comparative Biology 42, n.º 3 (1 de julho de 2002): 619–32. http://dx.doi.org/10.1093/icb/42.3.619.

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3

Thanos, Panayotis, Seiichiro Okajima e Julia Terzis. "Ultrastructure and Cellular Biology of Nerve Regeneration". Journal of Reconstructive Microsurgery 14, n.º 06 (agosto de 1998): 423–36. http://dx.doi.org/10.1055/s-2007-1000203.

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4

Zhang, Li, Bijia Song, Xuan Zhang, Mu Jin, Lixin An, Tiandong Han, Fan Liu e Zhiyao Wang. "Resveratrol Ameliorates Trigeminal Neuralgia-Induced Cognitive Deficits by Regulating Neural Ultrastructural Remodelling and the CREB/BDNF Pathway in Rats". Oxidative Medicine and Cellular Longevity 2022 (28 de novembro de 2022): 1–17. http://dx.doi.org/10.1155/2022/4926678.

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Chronic pain often leads to cognitive impairment. Resveratrol (Res), a natural polyphenol existing in Polygonum cuspidatum, has been widely investigated for its antinociceptive, anti-inflammatory, and neuroprotective properties. Our aim was to explore the ameliorating effects of resveratrol on pain-related behaviors and learning and memory deficits induced by cobra venom-induced trigeminal neuralgia (TN). The TN model of rats was established by injecting cobra venom solution beneath the epineurium of the infraorbital nerve. Resveratrol was intragastrically administered at a dose of 40 mg/kg twice daily beginning on postoperative day 15. CREB inhibitor 666-15 was intraperitoneally administered at a dose of 10 mg/kg from POD 35-42 after morning resveratrol treatment. Mechanical allodynia was measured via von Frey filaments. Rat free movement was videotaped and analyzed. Spatial learning and memory were evaluated via the Morris water maze test. Ultrastructures of the hippocampal DG region and infraorbital nerve were observed by transmission electron microscopy. We found that resveratrol alleviated TN-induced allodynia, ameliorated learning and memory deficits, restored the ultrastructure of hippocampal neurons and synapses, repaired the damaged myelin sheath of the infraorbital nerve, and activated the CREB/BDNF pathway in the hippocampus of TN rats. CREB inhibitor administration suppressed the resveratrol-rescued abnormal hippocampal ultrastructural changes and aggravated spatial learning and memory impairment by inhibiting CREB/BDNF pathway activation in the hippocampus. Our findings indicated that resveratrol alleviated pain and improved cognitive deficits, probably by regulating neural ultrastructure remodelling and the CREB/BDNF pathway.

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5

Barnabas, A. D., P. Bunsi, Y. Naidoo, W. J. Przybylowicz e J. Mesjasz-Przybylowicz. "Effects Of Varying Salinity On Leaf Ultrastructure Of Potamogeton Pectinatus L". Microscopy and Microanalysis 5, S2 (agosto de 1999): 1256–57. http://dx.doi.org/10.1017/s1431927600019607.

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Potamogeton pectinatus is a submerged halophyte which occurs in waters of low salinity (5% to 10%). Its upper salinity tolerance has been reported to be 19%. Reasons why P.pectinatus is unable to tolerate salinities in excess of 19%is important to our understanding of its biology. In the present study, leaf ultrastructure of plants growing at low salinity was compared with plants growing at high salinity in order to assess the effects of different salinities on the ultrastructure. Attention was focussed on ultrastructural changes occurring in the leaf epidermis, the main photosynthetic tissue.Plants were grown in seawater at two salinities : 5%(low salinity) and 20% (high salinity). Pieces of mature leaf blades from both treatments were harvested and prepared for Transmission Electron Microscopy (TEM) following standard procedures. The overall distribution and concentration of chlorine (CI) in the leaves was ascertained since this element is the most abundant anion in seawater and is important in considerations of salt tolerance in submerged halophytes.

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6

Pennec, Marcel Le, e Peter G. Beninger. "Ultrastructural characteristics of spermatogenesis in three species of deep-sea hydrothermal vent mytilids". Canadian Journal of Zoology 75, n.º 2 (1 de fevereiro de 1997): 308–16. http://dx.doi.org/10.1139/z97-039.

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To enhance our understanding of the reproductive biology of deep-sea hydrothermal vent mytilids, the histology of the male gonad and the ultrastructure of its gametes were studied in Bathymodiolus thermophilus, B. puteoserpentis, and B. elongatus. Specimens of B. thermophilus were collected at the 13°N site on the East Pacific ridge, while B. puteoserpentis were sampled from the Snake Pit site of the mid-Atlantic ridge and B. elongatus were obtained from the North Fiji Basin. Gonad histology conformed to the typical bivalve profile; the differences in the proportions of acinal and interacinal tissue, as well as differences in acinal fullness in B. puteoserpentis, indicate that gametogenesis is discontinuous in these deep-sea mytilids. Evidence of protandric hermaphroditism was observed in B. elongatus, which exhibited acini containing both maturing and residual male gametes and immature oocytes. The ultrastructural characteristics of the male gametes conform to those described for littoral bivalve species, and the spermatozoon is of the primitive type. No species-specific differences in spermatozoon ultrastructure were discerned. No evidence of bacterial inclusions was found in either the gametes or the associated gonad cells in any of the species examined. The male gametes are thus probably not vectors for the endosymbiotic bacteria that characterize the nutritional biology of the adults in this genus.

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7

Till, Gerd O. "Oxidants and Antioxidants: Ultrastructure and Molecular Biology Protocols". Archives of Pathology & Laboratory Medicine 127, n.º 8 (1 de agosto de 2003): 1054. http://dx.doi.org/10.5858/2003-127-1054a-oaauam.

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8

Comporti, Mario. "Oxidants and Antioxidants: Ultrastructure and Molecular Biology Protocols". Tissue and Cell 35, n.º 2 (abril de 2003): 153. http://dx.doi.org/10.1016/s0040-8166(02)00108-8.

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9

Lucocq, John. "Unbiased 3-D quantitation of ultrastructure in cell biology". Trends in Cell Biology 3, n.º 10 (outubro de 1993): 354–58. http://dx.doi.org/10.1016/0962-8924(93)90106-b.

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10

Griffiths, Gareth. "Ultrastructure in cell biology: do we still need it?" European Journal of Cell Biology 83, n.º 6 (2004): 245–51. http://dx.doi.org/10.1078/0171-9335-00375.

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11

Saucedo, José Edmundo Nava, Jean-Noël Barbotin, Martine Velut e Daniel Thomas. "Ultrastructural examination of Gibberella fujikuroi mycelia: effect of immobilization in calcium alginate beads". Canadian Journal of Microbiology 35, n.º 12 (1 de dezembro de 1989): 1118–31. http://dx.doi.org/10.1139/m89-187.

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Ultrastructural examination of free and calcium alginate immobilized Gibberella fujikuroi mycelia showed that in addition to the changes occurring during the transition phase from primary to secondary metabolism, there are several alterations in the ultrastructure of hyphae as a response to microenvironmental changes owing to immobilization constraints. Internal changes included (i) the presence of large glyoxisomelike bodies and of active vesicle-generating systems, which appeared as cloudy structures in electron micrographs; (ii) the formation of endocells, resulting in hyphae with up to three cell walls and the concomitant accumulation of secondary metabolites, mainly pigments, in peripheral cell compartments; and (iii) the progressive development of autophagic vacuoles involved in the turnover of cell constituents.Key words: Gibberella fujikuroi, immobilized fungi, alginate entrapment, ultrastructure modification, immobilization.

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12

Schauflinger, Martin, Tim Bergner, Gregor Neusser, Christine Kranz e Clarissa Read. "Potassium permanganate is an excellent alternative to osmium tetroxide in freeze-substitution". Histochemistry and Cell Biology 157, n.º 4 (5 de janeiro de 2022): 481–89. http://dx.doi.org/10.1007/s00418-021-02070-0.

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AbstractHigh-pressure freezing followed by freeze-substitution is a valuable method for ultrastructural analyses of resin-embedded biological samples. The visualization of lipid membranes is one of the most critical aspects of any ultrastructural study and can be especially challenging in high-pressure frozen specimens. Historically, osmium tetroxide has been the preferred fixative and staining agent for lipid-containing structures in freeze-substitution solutions. However, osmium tetroxide is not only a rare and expensive material, but also volatile and toxic. Here, we introduce the use of a combination of potassium permanganate, uranyl acetate, and water in acetone as complementing reagents during the freeze-substitution process. This mix imparts an intense en bloc stain to cellular ultrastructure and membranes, which makes poststaining superfluous and is well suited for block-face imaging. Thus, potassium permanganate can effectively replace osmium tetroxide in the freeze-substitution solution without sacrificing the quality of ultrastructural preservation.

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13

Siddique, A. B. M., e A. K. Bal. "Morphological and biochemical changes in peanut nodules during photosynthate stress". Canadian Journal of Microbiology 38, n.º 6 (1 de junho de 1992): 526–33. http://dx.doi.org/10.1139/m92-087.

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Nitrogen fixation in legume root nodules is believed to be supported by the supply of photosynthate of the current photoperiod. However, in peanut nodules, prolonged periods of darkness or detopping do not disrupt nitrogen fixation for at least 48 h. During this period, nodule oleosomes (lipid bodies) have been shown to decrease in number within the infected cells, and it has been suggested that lipids from oleosomes are mobilized to maintain the energy and carbon requirements of the nitrogen-fixing nodules. We present morphological evidence, at the ultrastructural level, for the utilization of oleosomes during photosynthate stress. The biochemical status of the nodule has also been assessed and correlated with ultrastructure. For comparison cowpea nodules were used that totally lacked oleosomes. In peanut nodules leghemoglobin and total protein remained unchanged along with integrated ultrastructure on nodule cells for 48 h, whereas in cowpea a decline in proteins with ultrastructural damage became apparent within a very short period of photosynthate stress. In peanut nodules empty or partially empty oleosomes were taken as evidence for their utilization during the stress period. Key words: N2 fixation, photosynthate stress, lipid bodies, catalase, malate synthase, peanut nodule, β-oxidation.

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14

MALTIN, C., e M. DELDAY. "Ultrastructure of incubated muscles". Cell Biology International Reports 10, n.º 9 (setembro de 1986): 699–705. http://dx.doi.org/10.1016/0309-1651(86)90127-x.

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15

Bayer, Edward A., Linda J. W. Shimon, Yuval Shoham e Raphael Lamed. "Cellulosomes—Structure and Ultrastructure". Journal of Structural Biology 124, n.º 2-3 (dezembro de 1998): 221–34. http://dx.doi.org/10.1006/jsbi.1998.4065.

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16

Young, Jeremy R., Sean A. Davis, Paul R. Bown e Stephen Mann. "Coccolith Ultrastructure and Biomineralisation". Journal of Structural Biology 126, n.º 3 (junho de 1999): 195–215. http://dx.doi.org/10.1006/jsbi.1999.4132.

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17

Barroso, P. A. A., L. R. F. M. Paulino, B. R. Silva, G. L. Vasconcelos, D. S. Gomes, M. F. Lima Neto, A. W. B. Silva et al. "Effects of dexamethasone on growth, viability and ultrastructure of bovine secondary follicles cultured in vitro". Zygote 28, n.º 6 (27 de agosto de 2020): 504–10. http://dx.doi.org/10.1017/s0967199420000416.

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SummaryThis study aimed to evaluate the effects of dexamethasone on development, viability, antrum formation and ultrastructural integrity of bovine secondary follicles cultured in vitro for 18 days. Bovine ovaries were obtained from slaughterhouses and secondary follicles of ~150–200 µm diameter were isolated and cultured in the laboratory in TCM-199+ alone or supplemented with different concentrations of dexamethasone (1, 10, 100 and 1000 ng/ml). Follicle viability was evaluated after the culture period, using calcein-AM (viable) and ethidium homodimer (nonviable). Follicle diameters and antrum formation were evaluated at days 0, 6, 12 and 18. Before or after in vitro culture, follicles were fixed for histological and ultrastructural analysis. Follicle diameters were evaluated using analysis of variance and Kruskal–Wallis test, while chi-squared test was used to evaluate the percentage of viable follicles and antrum formation (P < 0.05). Follicles cultured for 6 days with all treatments increased their diameters significantly, but there was no significant difference between treatments at the end of the culture period. In vitro cultured follicles showed antral cavity formation at the end of the culture period, but no influence of dexamethasone was seen. Ultrastructural analysis showed that follicles cultured with dexamethasone (1, 10, 100 and 1000 ng/ml) had well preserved granulosa cells. However, oocytes from follicles cultured with 10, 100 or 1000 ng/ml dexamethasone showed signs of degeneration. It can be concluded that follicles cultured in vitro in the presence of dexamethasone demonstrated continuous in vitro growth, but oocytes from follicles cultured with 10, 100 or 1000 ng/ml dexamethasone had poor ultrastructure.

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18

Ramzan, Faiqah, Irfan Zia Qureshi e Muhammad Haris Ramzan. "Dose-Dependent Degeneration of Leydig Cells Following Kisspeptin-10 Administration: An Ultrastructural Study". Protein & Peptide Letters 29, n.º 1 (janeiro de 2022): 64–70. http://dx.doi.org/10.2174/0929866528666211213090033.

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Background: The discovery of kisspeptin signaling as a key regulator of gonadotropin- releasing hormone (GnRH) secretion from the hypothalamus enhanced our understanding of the neuroendocrine regulation of mammalian reproduction. Effects of central and peripheral administration of kisspeptin on plasma gonadotropins, testosterone, and spermatogenesis are studied in detail. Objective: The present study was conducted to check the ultrastructure of Leydig cells in prepubertal male rats in response to the administration of a range of kisspeptin doses. Method: We administered a range of kisspeptin-10 doses (1 μg, 1 ηg, and 10 ρg) intraperitoneally to prepubertal male Sprague-Dawley rats (PND 35) twice daily after every 12 hours. Control rats were injected with physiological saline in parallel. Results: At the end of the treatment, plasma concentrations of testosterone were measured by competitive binding radioimmunoassay, and small pieces of rat testicular tissue were processed for electron microscopy to examine the ultrastructure of Leydig cells. Plasma testosterone concentration was reduced significantly at 1ηg (P<0.05) and 1μg (P<0.01) doses as compared to control. Distinct ultrastructural changes categorized as dilatation of cytoplasmic organelles, irregularly shaped nuclei with nuclear membrane invaginations, reduced nuclear sizes, degeneration, and vacuolation were observed in the kisspeptin-10 treated Leydig cells as compared to control. Quantification of the data showed reduced Leydig cell indices and hyperplasia of the interstitial cells. Conclusion: It is concluded that chronic intermittent administration of kisspeptin-10 has a dose-dependent degenerative effect on the plasma testosterone levels and Leydig cells ultrastructure in prepubertal male rats.

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19

Kerrigan, Julia, e Jack D. Rogers. "Biology, ecology and ultrastructure ofAscobotryozymaandBotryozyma, unique commensal nematode-associated yeasts". Mycologia 105, n.º 1 (janeiro de 2013): 34–51. http://dx.doi.org/10.3852/12-041.

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20

ZUCKER-FRANKLIN, DOROTHEA, CLAIRE STAHL e PHYLLIS HYDE. "Megakaryocyte Ultrastructure." Annals of the New York Academy of Sciences 509, n.º 1 Factor VIII/v (novembro de 1987): 25–33. http://dx.doi.org/10.1111/j.1749-6632.1987.tb30979.x.

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21

GOBERT, G. N., M. CHAI e D. P. McMANUS. "Biology of the schistosome lung-stage schistosomulum". Parasitology 134, n.º 4 (17 de novembro de 2006): 453–60. http://dx.doi.org/10.1017/s0031182006001648.

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Past and more recent research has examined the ultrastructure, metabolism, cell biology, genomics and post-genomics of schistosome schistosomula. These areas are considered and discussed in this review with particular emphasis on (1) the early migration phases through the host, (2) interaction of the host immune response with the parasite surface, (3) glucose uptake mechanisms, and (4) defining the transcriptional profiles of lung-stage schistosomula compared with other developmental stages using microarrays. The microarray profiling studies suggest caution is required when considering the use of schistosomes obtained byin vitromeans for molecular or biochemical studies.

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22

Wang, Liang, Ziyi Yan, Helena Vihinen, Ove Eriksson, Weihuan Wang, Rabah Soliymani, Yao Lu et al. "FAM92A1 is a BAR domain protein required for mitochondrial ultrastructure and function". Journal of Cell Biology 218, n.º 1 (7 de novembro de 2018): 97–111. http://dx.doi.org/10.1083/jcb.201806191.

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Mitochondrial function is closely linked to its dynamic membrane ultrastructure. The mitochondrial inner membrane (MIM) can form extensive membrane invaginations known as cristae, which contain the respiratory chain and ATP synthase for oxidative phosphorylation. The molecular mechanisms regulating mitochondrial ultrastructure remain poorly understood. The Bin-Amphiphysin-Rvs (BAR) domain proteins are central regulators of diverse cellular processes related to membrane remodeling and dynamics. Whether BAR domain proteins are involved in sculpting membranes in specific submitochondrial compartments is largely unknown. In this study, we report FAM92A1 as a novel BAR domain protein localizes to the matrix side of the MIM. Loss of FAM92A1 caused a severe disruption to mitochondrial morphology and ultrastructure, impairing organelle bioenergetics. Furthermore, FAM92A1 displayed a membrane-remodeling activity in vitro, inducing a high degree of membrane curvature. Collectively, our findings uncover a role for a BAR domain protein as a critical organizer of the mitochondrial ultrastructure that is indispensable for mitochondrial function.

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23

Sara, Alan, Janet M. Bruner e Bruce Mackay. "Ultrastructure of Ependymoma". Ultrastructural Pathology 18, n.º 1-2 (janeiro de 1994): 33–42. http://dx.doi.org/10.3109/01913129409016272.

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24

Yang, Zhaofu, e Yalin Zhang. "Comparison of ultrastructure among sibling species of Ostrinia (Lepidoptera: Crambidae) from China". Canadian Entomologist 143, n.º 2 (abril de 2011): 126–35. http://dx.doi.org/10.4039/n10-049.

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AbstractScanning electron microscopy on the ultrastructure of scales on the forewings and labial palpi suggests species-diagnostic differences among six sibling species of the genus Ostrinia Hübner. Among four species with small mid-tibiae, O. furnacalis (Guenée) and O. nubilalis (Hübner) show similar ultrastructure of the distal forewing scales, which is distinctly different from that of O. orientalis Mutuura and Munroe and O. dorsivittata (Moore). The diameter of windows between longitudinal ridges and cross ribs of forewing scales in O. dorsivittata is the largest among examined species, and clearly different from that in the other three small mid-tibiae species. Scales of the labial palpi of O. orientalis have indistinct vestigial windows; windows of O. nubilalis are more numerous and larger than in the other three small mid-tibiae species. Among two species with massive mid-tibiae, window diameter of forewing scales is larger in O. zealis (Guenée) than in O. scapulalis (Walker). Moreover, the number and diameter of windows in scales of the labial palpi differs between these two species. In addition to other known morphological differences, these ultrastructural differences provide further evidence that closely related Ostrinia species are distinct.

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25

Nawaz, Mohamed S., e W. M. Hess. "Ultrastructure ofNeovossia HorridaTeliospores". Mycologia 79, n.º 2 (março de 1987): 173–79. http://dx.doi.org/10.1080/00275514.1987.12025695.

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26

Gatti, Marta, Manuel Belli, Mariacarla De Rubeis, Mohammad Ali Khalili, Giuseppe Familiari, Stefania Annarita Nottola, Guido Macchiarelli, Edmond Hajderi e Maria Grazia Palmerini. "Ultrastructural Evaluation of Mouse Oocytes Exposed In Vitro to Different Concentrations of the Fungicide Mancozeb". Biology 12, n.º 5 (10 de maio de 2023): 698. http://dx.doi.org/10.3390/biology12050698.

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Mancozeb is a widely used fungicide, considered to be an endocrine disruptor. In vivo and in vitro studies evidenced its reproductive toxicity on mouse oocytes by altering spindle morphology, impairing oocyte maturation, fertilization, and embryo implantation. Mancozeb also induces dose-dependent toxicity on the ultrastructure of mouse granulosa cells, including chromatin condensation, membrane blebbing, and vacuolization. We evaluated the effects on the ultrastructure of mouse oocytes isolated from cumulus-oocyte complexes (COCs), exposed in vitro to increasing concentrations of mancozeb. COCs were matured in vitro with or without (control) low fungicide concentrations (0.001–1 μg/mL). All mature oocytes were collected and prepared for light and transmission electron microscopy. Results showed a preserved ultrastructure at the lowest doses (0.001–0.01 μg/mL), with evident clusters of round-to-ovoid mitochondria, visible electron-dense round cortical granules, and thin microvilli. Mancozeb concentration of 1 μg/mL affected organelle density concerning controls, with a reduction of mitochondria, appearing moderately vacuolated, cortical granules, and microvilli, short and less abundant. In summary, ultrastructural data revealed changes mainly at the highest concentration of mancozeb on mouse oocytes. This could be responsible for the previously described impaired capability in oocyte maturation, fertilization, and embryo implantation, demonstrating its impact on the reproductive health and fertility.

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Willingale-Theune, J., M. Schweiger, M. Hirsch-Kauffmann, A. E. Meek, M. Paulin-Levasseur e P. Traub. "Ultrastructure of Fanconi anemia fibroblasts". Journal of Cell Science 93, n.º 4 (1 de agosto de 1989): 651–65. http://dx.doi.org/10.1242/jcs.93.4.651.

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Employing indirect immunofluorescence and conventional electron microscopy, gross nuclear aberrations were observed in cultured interphase fibroblasts derived from a patient suffering from Fanconi's anemia (FA). Such aberrations were predominantly expressed in cells at high passages between 28 and 34. The structure of the nuclei appeared compound in nature, often consisting of two to three nuclear fragments connected to each other by thin nuclear bridges containing chromatin and nuclear lamin material. In other cases, the nuclei appeared lobed or budded but the cells did not contain distinct nuclear fragments. Chromatin was conspicuously absent from some nuclear lobes, revealing empty, cage-like structures comprising nuclear lamin material. Micronuclei were often abundant in the perinuclear cytoplasm but in some instances they appeared to be composed of chromatin lacking a delineating nuclear lamin matrix. Residual cytoskeletons examined by whole-mount electron microscopy revealed a network of intermediate filaments (IFs) within FA fibroblasts forming a bridge between the plasma membrane and the nucleus or its major fragments. In addition, there were thinner, 3–4 nm filaments connecting individual IFs with the surface of the nucleus. Micronuclei that were not connected to the main nuclear body, but which were delineated by a distinct lamina and possessed nuclear pores, did not appear to be anchored to the IF network. Multinuclearity, nuclear fragmentation, irregular chromatin distribution and inter-nuclear chromatin/lamin bridges might result from a failure in the redistribution of chromatin to sister nuclei, incomplete cytokinesis and proliferation of nuclear envelope material. These phenomena point to precocious aging of FA fibroblasts and may occur as a consequence of spontaneous damage to the sister chromatids or through the action of DNA-toxic agents.

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Kozel, Beth A., e Robert P. Mecham. "Elastic fiber ultrastructure and assembly". Matrix Biology 84 (novembro de 2019): 31–40. http://dx.doi.org/10.1016/j.matbio.2019.10.002.

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Svitkina, Tatyana M. "Ultrastructure of the actin cytoskeleton". Current Opinion in Cell Biology 54 (outubro de 2018): 1–8. http://dx.doi.org/10.1016/j.ceb.2018.02.007.

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Gusmão-Pompiani, P., C. Oliveira e I. Quagio-Grassiotto. "Spermatozoa ultrastructure in Sciaenidae and Polynemidae (Teleostei:Perciformes) with some consideration on Percoidei spermatozoa ultrastructure". Tissue and Cell 37, n.º 3 (junho de 2005): 177–91. http://dx.doi.org/10.1016/j.tice.2004.12.003.

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Sukkhee, Nutchar, Tappadit Mitparian, Tassaporn Kanjanarakha, Sinlapachai Senarat, Niwat Kangwanrangsan, Gen Kaneko e Jes Kettratad. "Spermatozoon of the wild scalloped perchlet, Ambassis nalua (Hamilton, 1822): Ultrastructure and morphometric analysis". Veterinary Integrative Sciences 20, n.º 1 (6 de setembro de 2021): 199–208. http://dx.doi.org/10.12982/vis.2022.016.

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The description of sperm morphology is fundamental in the reproductive biology of fishes, but this information is limited in the family Ambassidae. Our report hence focused on the ultrastructure and morphometric analysis of spermatozoa in a pelagic fish Ambassis nalua. All fish (n = 75) were obtained during January and March 2017 from the Estuarine Pranburi River, Thailand. The standard length of fish used in this study was 3.4 ± 0.12 cm (mean ± standard deviation). All specimens were considered mature based on the abundance of spermatozoa in the testis. The testicular organs were collected and observed using standard histology and transmission electron microscopy (TEM). Ultrastructural observation associated with morphometric analysis showed that spermatozoa are structurally long cells of approximately 51.17 ± 4.54 µm total length, composed of a head, a midpiece and a tail. The head had no acrosome, and the granular structure of condensed chromatin was observed within the ovoid nucleus. The midpiece consisted of a short cylindrical region with the length of 1.29 ± 0.87 µm in diameter, having the centriolar complex organization and eight mitochondria (approx. 0.32 ± 0.02 µm each). The uniflagellar tail was clearly identified with a classical 9+2 arrangements of microtubules. Based on these characteristics, the spermatozoon of wild scalloped perchlet are considered as uniflagellate anacrosomal aquqsperm. The morphological features, including the number of mitochondria, may be used for further cryopreservation and in the evolutionary biology of this species.

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Dorsey, Charles H., Carolyn E. Cousin, Fred A. Lewis e Margaret A. Stirewalt. "Ultrastructure of the Schistosoma mansoni cercaria". Micron 33, n.º 3 (janeiro de 2002): 279–323. http://dx.doi.org/10.1016/s0968-4328(01)00019-1.

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Harris, J. R. "The ultrastructure of multinucleate giant cells". Micron 24, n.º 2 (janeiro de 1993): 173–231. http://dx.doi.org/10.1016/0968-4328(93)90070-h.

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Luther, Pradeep K., Peter M. G. Munro e John M. Squire. "Muscle ultrastructure in the teleost fish". Micron 26, n.º 5 (janeiro de 1995): 431–59. http://dx.doi.org/10.1016/0968-4328(95)00015-1.

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van Doorn, Wouter G., e Alessio Papini. "Ultrastructure of autophagy in plant cells". Autophagy 9, n.º 12 (5 de dezembro de 2013): 1922–36. http://dx.doi.org/10.4161/auto.26275.

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Parton, Robert G. "Caveolae — from ultrastructure to molecular mechanisms". Nature Reviews Molecular Cell Biology 4, n.º 2 (fevereiro de 2003): 162–67. http://dx.doi.org/10.1038/nrm1017.

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WEIS, VIRGINIA M., DOUGLAS R. KEENE e LEO W. BUSS. "BIOLOGY OF HYDRACTINIID HYDROIDS. 4. ULTRASTRUCTURE OF THE PLANULA OFHYDRACTINIA ECHINATA". Biological Bulletin 168, n.º 3 (junho de 1985): 403–18. http://dx.doi.org/10.2307/1541521.

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Osborn, Jeffrey M., Thomas N. Taylor e Edward L. Schneider. "POLLEN MORPHOLOGY AND ULTRASTRUCTURE OF THE CABOMBACEAE: CORRELATIONS WITH POLLINATION BIOLOGY". American Journal of Botany 78, n.º 10 (outubro de 1991): 1367–78. http://dx.doi.org/10.1002/j.1537-2197.1991.tb12603.x.

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Khursigara, Cezar M., Susan F. Koval, Dianne M. Moyles e Robert J. Harris. "Inroads through the bacterial cell envelope: seeing is believing". Canadian Journal of Microbiology 64, n.º 9 (setembro de 2018): 601–17. http://dx.doi.org/10.1139/cjm-2018-0091.

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A singular feature of all prokaryotic cells is the presence of a cell envelope composed of a cytoplasmic membrane and a cell wall. The introduction of bacterial cell fractionation techniques in the 1950s and 1960s along with developments in procedures for electron microscopy opened the window towards an understanding of the chemical composition and architecture of the cell envelope. This review traces the contribution of Terry Beveridge in these endeavours, beginning with his doctoral studies in the 1970s on the structure of paracrystalline surface arrays (S-layers), followed by an exploration of cryogenic methods for preserving bacteria for ultrastructural analyses. His insights are reflected in a current example of the contribution of cryo-electron microscopy to S-layer studies — the structure and assembly of the surface array of Caulobacter crescentus. The review then focuses on Terry’s contributions to imaging the ultrastructure of bacterial cell envelopes and to the development of cryo-electron microscopy techniques, including the use of CEMOVIS (Cryo-electron Microscopy of Vitreous Sections) to “see” the ultrastructure of the Gram-positive cell envelope — his last scientific endeavour.

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Li, Wei. "Ultrastructure of Synergids in Sugar Beet". Advanced Materials Research 926-930 (maio de 2014): 1040–44. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.1040.

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We use TEM to study the synergids in sugar beet, so as to provide more information for reproductive biology of angiosperm. Results were as follows: two synergids were similar in flower bud stage. Both of them show polarity with developed filiform apparatus (FA) at micropyle end and lacked cell wall at chalazal end. Then electron density in one synergid increased which suggested cell degeneration began. Complete degeneration finished before pollination. Organelles including mitochondrium, plastids and ribosomes gradually increased in the other synergid (persistent synergid). Metabolism of persistent synergid gradually enhanced. It began to degenerate when zygote had alveolate cell wall at the chalazal end, while completely degeneration and disappearance of FA took place at late stage of zygote. The results suggested that degeneration of one synergid in sugar beet must be triggered by other stimulation than pollination and pollen tube growth. As a transfer cell, persistent synergid transported nutrition for the development of embryo sac.

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Jones, P. R., e R. D. Butler. "Spermatozoon ultrastructure of Platichthys flesus". Journal of Ultrastructure and Molecular Structure Research 98, n.º 1 (janeiro de 1988): 71–82. http://dx.doi.org/10.1016/s0889-1605(88)80935-2.

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Bernardini, Giovanni, Roberto Stipani e Giumo Melone. "The ultrastructure of Xenopus spermatozoon". Journal of Ultrastructure and Molecular Structure Research 94, n.º 2 (fevereiro de 1986): 188–94. http://dx.doi.org/10.1016/0889-1605(86)90065-0.

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Pujol-Moix, Nuria, Mariana Corrochano, Isabel Badell, Joan Carles Souto e Josep F. Nomdedeu. "Platelet Ultrastructure in Familial Platelet Disorder with Associated Myeloid Malignancy (FPDMM)". Blood 136, Supplement 1 (5 de novembro de 2020): 37–38. http://dx.doi.org/10.1182/blood-2020-142248.

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The familial platelet disorder with associated myeloid malignancy (FPDMM) is an autosomal dominant platelet disorder, caused by germline RUNX1 mutations, with predisposition to develop hematologic malignancies, especially acute myeloid leukemia. In many of the FPDMM families reported, the platelet defect was a delta-storage-pool disease (d-SPD) which can also be found without leukemia propensity. However, it has not been studied whether the two types of d-SPD have a common nature. Platelet ultrastructure, previously very little studied, may be one of the aspects to be analyzed to solve this question. We analyzed the ultrastructural characteristics of platelets in 5 members of a family with FPDMM. The family included three generations and all affected members had a RUNX1 deletion: chr21:36349450-36572837 (Rio-Machin et al. Nat Commun 2020;11:1044). None of the patients studied had developed leukemia at the time of the platelet study. We compared the results with those of 24 patients with d-SPD non-associated with leukemia and with those of 15 healthy individuals. Platelets were processed by transmission electron microscopy by standard methods. On the electron micrographs, morphometric analysis of the following structures was performed: 1) Platelets: size and shape, 2) Intraplatelet corpuscular structures (dense granules, alpha granules, mitochondria, lipid droplets): size and number (per platelet and per square micrometer of platelet area), 3) Surface-connected canalicular system (SCS): mean area of individual channel sections and mean percentage of the total SCS area with respect to the platelet area, 4) Glycogen masses: total area with respect to the platelet area. The morphological traits of the platelets and organelles measured above were also evaluated and the dense granules were classified into 4 different types depending on the appearance of their solid core (Weiss et al. Br J Haematol 1993;83:282). The dense tubular system and other ultrastructural characteristics were evaluated by morphology only. The main features of the platelet ultrastructure in patients with FPDMM were (Fig 1, Table 1): 1) slight increase in platelet size while preserving the discoidal shape, 2) moderate reduction in the number of dense granules, which showed a reduced proportion of type 1 granules (with the solid core occupying more than 50 % of the granule) and an increased proportion of type 2 and type 3 granules, with a solid core reduced or fragmented respectively, 3) marked increase and dilatation of SCS with some elements filled by a substance of unknown origin, 4) moderate increase in dense tubular system with occasional complex formation. The platelet ultrastructure was similar to that described in the non-associated d-SPD group (Pujol-Moix et al. Haematologica 2000;85:619) although there were some differences (Table 1): in FPDMM platelets the dense granules were less reduced but more dysmorphic, and the SCS, equally dilated, contained a substance that was not observed in the d-SPD platelets. Given that all the findings described belong to the same family, it would be necessary to evaluate the platelet ultrastructure in additional families and extend the study to other characteristics of d-SPD. Only in this way, it would be possible to know to what extent the platelet defect of FPDMM and that of non-associated d-SPD shared a pathogenic mechanism. Disclosures No relevant conflicts of interest to declare.

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Dahlbäck, B. "Ultrastructure of human coagulation factor V." Journal of Biological Chemistry 260, n.º 3 (fevereiro de 1985): 1347–49. http://dx.doi.org/10.1016/s0021-9258(18)89592-8.

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Holm-nielsen, Peter, e T. Steen Olsen. "Ultrastructure of Renal Adenoma". Ultrastructural Pathology 12, n.º 1 (janeiro de 1988): 27–39. http://dx.doi.org/10.3109/01913128809048474.

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Rodriguez, Moses, e Bernd Scheithauer. "Ultrastructure of Multiple Sclerosis". Ultrastructural Pathology 18, n.º 1-2 (janeiro de 1994): 3–13. http://dx.doi.org/10.3109/01913129409016267.

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Holzinger, Andreas. "Ultrastructure of plant cells". Protoplasma 258, n.º 6 (30 de setembro de 2021): 1167–69. http://dx.doi.org/10.1007/s00709-021-01706-1.

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Uribe-Uribe, Norma Ofelia, e Guillermo A. Herrera. "Ultrastructure of Tubular Casts". Ultrastructural Pathology 30, n.º 3 (janeiro de 2006): 159–66. http://dx.doi.org/10.1080/01913120600689749.

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Orenstein, Jan Marc. "Ultrastructure of Kaposi Sarcoma". Ultrastructural Pathology 32, n.º 5 (janeiro de 2008): 211–20. http://dx.doi.org/10.1080/01913120802343871.

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Lee, Hoi-Seon, e L. Copeland. "Ultrastructure of chickpea nodules". Protoplasma 182, n.º 1-2 (março de 1994): 32–38. http://dx.doi.org/10.1007/bf01403686.

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