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排序方式: 共有458条查询结果,搜索用时 31 毫秒
101.
QUANTITATIVE AUTORADIOGRAPHIC STUDY OF LABELED RNA IN RABBIT OPTIC NERVE AFTER INTRAOCULAR INJECTION OF [3H]URIDINE 总被引:1,自引:1,他引:0 下载免费PDF全文
Pierluigi Gambetti Lucila Autilio-Gambetti Brenda Shafer LaDorna Pfaff 《The Journal of cell biology》1973,59(3):677-684
The distribution of labeled RNA in the optic nerve of the rabbit was studied by quantitative ultrastructural autoradiography after the intraocular injection of [3H]uridine. The highest density of silver grains related to [3H]RNA (27–40 grains/100 µm2) was found in glial cell perikarya; a slightly lower density was present in the glial nuclei (19–20 grains/100 µm2). Axons (4–5 grains/100 µm2) and myelin (2–3 grains/100 µm2) had the lowest grain densities. 74–83% of all counted grains were located outside the axons. By comparing the grain density distribution over the axon with that expected in the case of an exclusive labeling of the surrounding myelin and glial cell processes, it was concluded that the axons contained a number of grains representing [3H]RNA significantly higher than that expected to scatter from myelin and glial processes. Most of these grains were concentrated at the periphery of the axon and were not related to axonal mitochondria. 相似文献
102.
THE FINE STRUCTURE OF PUROMYCIN-INDUCED CHANGES IN MOUSE ENTORHINAL CORTEX 总被引:8,自引:2,他引:6 下载免费PDF全文
Pierluigi Gambetti Nicholas K. Gonatas Louis B. Flexner 《The Journal of cell biology》1968,36(2):379-390
Bitemporal intracerebral injections of puromycin in mice suppress indefinitely expression of memory of avoidance-discrimination learning. Ultrastructural studies of the entorhinal cortex of puromycin-treated mice revealed the following: (a) Abnormalities were not observed in presynaptic terminals and synaptic clefts; many postsynaptic dendrites or somas contained swollen mitochondria. (b) Dispersion of polyribosomes into single units or condensation of ribosomes into irregular aggregates with loss of "distinctiveness" was noted in a few neurons 7–27 hr after puromycin treatment. (c) Cytoplasmic aggregates of granular or amorphous material were frequently noted within otherwise normal neuronal perikarya. (d) Mitochondria in many neuronal perikarya and dendrites were swollen. Mitochondria in axons, presynaptic terminals, and glial cells were unaltered. The relationships between these lesions and the effect of puromycin on protein synthesis and memory are examined. It is suggested that the disaggregation of polysomes is too limited to explain the effect of puromycin on memory. Special emphasis is given to the swelling of mitochondria. The possible mechanisms and the significance of this lesion are discussed. 相似文献
103.
Donato Di Monte Giorgio Bellomo Hjördis Thor Pierluigi Nicotera Sten Orrenius 《Archives of biochemistry and biophysics》1984,235(2):343-350
The toxicological implications of alterations in intracellular thiol homeostasis during menadione metabolism have been investigated using freshly isolated rat hepatocytes. A strict correlation between depletion of protein sulfhydryl groups and loss of cell viability was observed. Loss of protein thiols preceded cell death, and occurred more rapidly in cells with decreased levels of reduced glutathione. Depletion of protein thiols was also associated with inhibition of Ca2+ efflux from the cells and perturbation of intracellular Ca2+ homeostasis. It is proposed that the oxidative stress induced by menadione metabolism in isolated hepatocytes results in the depletion of both soluble and protein thiols, and that the latter effect is critically associated with a perturbation of Ca2+ homeostasis and loss of cell viability. 相似文献
104.
Pietro Dri Barbara Bisiacchi Rita Cramer Paolo Bellavite Giuseppina de Nicola Pierluigi Patriarca 《Molecular and cellular biochemistry》1978,22(2-3):159-166
Summary The oxidative response to phagocytosis by chicken polymorphonuclear leucocytes was investigated as compared to guinea pig polymorphonuclear leucocytes.The polymorphs from both species respond to phagocytosis with an increased oxygen consumption, an increased generation of O2
– and H2O2, and an increased oxidation of glucose through the hexose monophosphate shunt. The rate of oxygen consumption, and generation of O2
– and H2O2 by phagocytosing chicken polymorphonuclear leucocytes is considerably lower than with phagocytosing guinea pig polymorphonuclear leucocytes. By contrast, the extent of hexose monophosphate shunt stimulation in chicken polymorphs is comparable to that of guinea pig polymorphs. Evidence is presented suggesting that H2O2 is preferentially degraded in chicken cells through the glutathione cycle, whereas catalase and myeloperoxidase are the two main H2O2 degrading enzymes in guinea pig cells.The 20,000 g fraction of the postnuclear supernatant of chicken polymorphs contains a cyanide-insensitive NADPH oxidizing activity which is stimulated during phagocytosis. Similar properties for the NADPH oxidizing activity of guinea pig polymorphs have been previously reported.It is concluded that the metabolic burst of phagocytosing chicken polymorphonuclear leucocytes is qualitatively similar to that of guinea pig polymorphonuclear leucocytes, but the latter cells are more active in all the biochemical parameters that have been measured. The difference in the H2O2 degradation pathways between the two species is accounted for by the lack of myeloperoxidase and catalase in chicken polymorphs. 相似文献
105.
106.
Pilla P Sandomenico A Malachovská V Borriello A Giordano M Cutolo A Ruvo M Cusano A 《Biosensors & bioelectronics》2012,31(1):486-491
We present a fast and effective method for anchoring bioreceptors to optical waveguides exhibiting a poorly reactive polymer interface and that have to be minimally perturbed with respect to their design. The study originated from the need to biofunctionalize a fiber optic Long Period Grating (LPG) that is tuned in a highly sensitive working point, the so-called transition mode, through the deposition of a high refractive index overlay. In particular, a thin film of atactic polystyrene (PS) was dip-coated onto the LPG with a thickness suitable to optimize the LPG sensitivity to refractive index changes of the surrounding medium. Bovine serum albumin was selected as sacrificial layer for its well-known adhesion capabilities to PS surfaces, then glutaraldehyde was used to conjugate IgGs, serving as prototypical bioreceptor, on the device surface. The effectiveness of the immobilization method was assessed by studying the interaction between the immobilized IgG with a suitable anti-IgG. In a preliminary study performed by means of ELISA and surface plasmon resonance, optimal conditions for the biomolecular testing with the LPG were assessed. Four distinct interactions were thus monitored in real time following the shift of the LPG attenuation band. These experiments suggest a novel and interesting biofunctionalization approach of unreactive polymers with applications in immunosensing and basic life science research. 相似文献
107.
Federica Laudisi Manolo Sambucci Francesca Nasta Rosanna Pinto Rossella Lodato Pierluigi Altavista Giorgio Alfonso Lovisolo Carmela Marino Claudio Pioli 《Bioelectromagnetics》2012,33(8):652-661
Wireless local area networks are an increasing alternative to wired data networks in workplaces, homes, and public areas. Concerns about possible health effects of this type of signal, especially when exposure occurs early in life, have been raised. We examined the effects of prenatal (in utero) exposure to wireless fidelity (WiFi) signal‐associated electromagnetic fields (2450 MHz center‐frequency band) on T cell development and function. Pregnant mice were exposed whole body to a specific absorption rate of 4 W/kg, 2 h per day, starting 5 days after mating and ending 1 day before the expected delivery. Sham‐exposed and cage control groups were used as controls. No effects on cell count, phenotype, and proliferation of thymocytes were observed. Also, spleen cell count, CD4/CD8 cell frequencies, T cell proliferation, and cytokine production were not affected by the exposure. These findings were consistently observed in the male and female offspring at early (5 weeks of age) and late (26 weeks of age) time points. Nevertheless, the expected differences associated with aging and/or gender were confirmed. In conclusion, our results do not support the hypothesis that the exposure to WiFi signals during prenatal life results in detrimental effects on the immune T cell compartment. Bioelectromagnetics 33:652–661, 2012. © 2012 Wiley Periodicals, Inc. 相似文献
108.
Nathan M. Kleczewski Daniel A. Herms Pierluigi Bonello 《Trees - Structure and Function》2012,26(2):525-533
In managed settings, seedlings are often fertilized with the objective of enhancing establishment, growth, and survival. However,
responses of seedlings to fertilization can increase their susceptibility to abiotic stresses such as drought. Seedlings acclimate
to variation in soil resources by reallocating carbon among different physiological processes and compartments, such as above
versus belowground growth, secondary metabolism, and support of ectomycorrhizal fungi (EMF). We examined the effects of nutrient
and water availability on carbon allocation to above and belowground growth of river birch (Betula nigra), as well as partitioning among root sugars, starch, phenolics, lignin, and EMF abundance. As nutrient availability increased,
total plant biomass and total leaf area increased, while percent root biomass decreased. Root sugars, total root phenolics
and EMF abundance responded quadratically to nutrient availability, being lowest at intermediate fertility levels. Decreased
water availability reduced total leaf area and root phenolics relative to well-watered controls. No interactions between nutrient
and water availability treatments were detected, which may have been due to the moderate degree of drought stress imposed
in the low water treatment. Our results indicate that nutrient and water availability significantly alter patterns of carbon
allocation and partitioning in roots of Betula nigra seedlings. The potential effects of these responses on stress tolerance are discussed. 相似文献
109.
Casadei R Piovesan A Vitale L Facchin F Pelleri MC Canaider S Bianconi E Frabetti F Strippoli P 《Genomics》2012,100(2):125-130
The "5' end mRNA artifact" issue refers to the incorrect assignment of the first AUG codon in an mRNA, due to the incomplete determination of its 5' end sequence. We performed a systematic identification of coding regions at the 5' end of all human known mRNAs, using an automated expressed sequence tag (EST)-based approach. Following parsing of more than 7 million BLAT alignments, we found 477 human loci, out of 18,665 analyzed, in which an extension of the mRNA 5' coding region was identified. Proof-of-concept confirmation was obtained by in vitro cloning and sequencing for GNB2L1, QARS and TDP2 cDNAs, and the consequences for the functional studies of these loci are discussed. We also generated a list of 20,775 human mRNAs where the presence of an in-frame stop codon upstream of the known start codon indicates completeness of the coding sequence at 5' in the current form. 相似文献
110.
Pierluigi Maestrini Andrea Cavallini Milena Rizzo Tommaso Giordani Rodolfo Bernardi Mauro Durante Lucia Natali 《Journal of plant physiology》2009,166(14):391
Poplar is an important crop and a model system to understand molecular processes of growth, development and responses to environmental stimuli in trees. In this study, we analyzed gene expression in white poplar (Populus alba) plants subjected to chilling. Two forward suppression-subtractive-hybridization libraries were constructed from P. alba plants exposed to low non-freezing temperature for 6 or 48 h. Hundred and sixty-two cDNAs, 54 from the 6-h library and 108 from the 48-h library, were obtained. Isolated genes belonged to six categories of genes, specifically those that: (i) encode stress and defense proteins; (ii) are involved in signal transduction; (iii) are related to regulation of gene expression; (iv) encode proteins involved in cell cycle and DNA processing; (v) encode proteins involved in metabolism and energetic processes; and (vi) are involved in protein fate.Different expression patterns at 3, 6, 12, 24, 48 h at 4 °C and after a recovery of 24 h at 20 °C were observed for isolated genes, as expected according to the class in which the gene putatively belongs. Forty-four of 162 genes contained DRE/LTRE cis-elements in the 5′ proximal promoter of their orthologs in Populus trichocarpa, suggesting that they putatively belong to the CBF regulon. The results contribute new data to the list of possible candidate genes involved in cold response in poplar. 相似文献