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101.
Peroxynitrite-Induced Cytotoxicity in PC12 Cells: Evidence for an Apoptotic Mechanism Differentially Modulated by Neurotrophic Factors 总被引:10,自引:1,他引:9
†Alvaro G. Estévez ‡Rafael Radi †Luis Barbeito §Jordan T. Shin §John A. Thompson §# Joseph S. Beckman 《Journal of neurochemistry》1995,65(4):1543-1550
Abstract: Peroxynitrite is a powerful oxidant formed by the near-diffusion-limited reaction of nitric oxide with superoxide. Large doses of peroxynitrite (>2 m M ) resulted in rapid cell swelling and necrosis of undifferentiated PC12 cells. However, brief exposure to lower concentrations of peroxynitrite (EC50 = 850 µ M ) initially (3–4 h) caused minimal damage to low-density cultures. By 8 h, cytoplasmic shrinkage with nuclear condensation and fragmentation became increasingly evident. After 24 h, 36% of peroxynitrite-treated cells demonstrated these features associated with apoptosis. In addition, 46% of peroxynitrite-treated cells demonstrated DNA fragmentation (by terminal-deoxynucleotide transferase-mediated dUTP-digoxigenin nick end-labeling) after 7 h, which was inhibited by posttreatment with the endonuclease inhibitor aurintricarboxylic acid. Serum starvation also resulted in apoptosis in control cells (23%), the percentage of which was not altered significantly by peroxynitrite treatment. Although peroxynitrite is known to be toxic to cells, the present study provides a first indication that peroxynitrite induces apoptosis. Furthermore, pretreatment of cells with nerve growth factor or insulin, but not epidermal growth factor, was protective against peroxynitrite-induced apoptosis. However, both acidic and basic fibroblast growth factors greatly increased peroxynitrite-initiated apoptosis, to 63 and 70%, respectively. Thus, specific trophic factors demonstrate differential regulation of peroxynitrite-induced apoptosis in vitro. 相似文献
102.
Alfonso Calvo Luis M. Pastor Ramon Horn Jacinto Pallares 《The Histochemical journal》1995,27(9):670-680
Summary The glycoconjugates of hamster epididymis were investigated with conventional and lectin histochemistry. A zone of the caput
epididymis, with particular histochemical characteristics, has been differentiated. β-Elimination in combination with lectins
was used to establish the presence and distribution of N- and O-linked glycoconjugates. The epithelium, spermatozoa and the
intertubular matrix were rich in glycoconjugates. The Golgi apparatus and stereocilia of the principal cells were intensely
positive with HPA, PNA and SBA lectins. β-limination indicated that these cells contained abundant O-linked glycoconjugates.
Apical and clear cells presented a common lectin affinity; their reactivities towards WGA and UEA-I were very positive. These
cells probably contain abundant N-glycoconjugates. The spermatozoa were stained by periodic acid-Schiff (PAS) and by all the
lectins (especially in the acrosome), except by those with an affinity for α-l-fucosyl residues; the most intense reaction was found with HPA, WGA, PNA and SBA. Changes in the sperm lectin binding along
the ductus were observed: sperm flagellum abruptly acquired WGA and PNA labelling from the posterior caput, and HPA reactivity
was negative only in the zone between the caput and the corpus. 相似文献
103.
104.
Ana Poveda Juan Luis Asensio Manuel Martín-Pastor and Jesús Jiménez-Barbero 《Journal of biomolecular NMR》1997,10(1):29-43
1H-NMR cross-relaxation rates and nonselectivelongitudinal relaxation times have been obtained at two magnetic fields (7.0and 11.8 T) and at a variety of temperatures for the branchedtetrasaccharide methyl3-O--N-acetyl-galactosaminyl--galactopyranosyl-(14)[3-O--fucosyl]-glucopyranoside (1), an inhibitor of astrocyte growth. Inaddition, 13C-NMR relaxation data have also been recorded atboth fields. The 1H-NMR relaxation data have been interpretedusing different motional models to obtain proton–proton correlationtimes. The results indicate that the GalNAc and Fuc rings display moreextensive local motion than the two inner Glc and Gal moieties, since thosepresent significantly shorter local correlation times. The13C-NMR relaxation parameters have been interpreted in termsof the Lipari–Szabo model-free approach. Thus, order parameters andinternal motion correlation times have been deduced. As obtained for the1H-NMR relaxation data, the two outer residues possess smallerorder parameters than the two inner rings. Internal correlation times are inthe order of 100 ps. The hydroxymethyl groups have also different behaviour,with the exocyclic carbon on the glucopyranoside unit showing the highestS2. Molecular dynamics simulations using a solvated systemhave also been performed and internal motion correlation functions have beendeduced from these calculations. Order parameters and interproton distanceshave been compared to those inferred from the NMR measurements. The obtainedresults are in fair agreement with the experimental data. 相似文献
105.
Oleic Acid Inhibits Gap Junction Permeability and Increases Glucose Uptake in Cultured Rat Astrocytes 总被引:3,自引:2,他引:1
Eva Lavado Luis I. Sánchez-Abarca Arantxa Tabernero Juan P. Bolaños José M. Medina 《Journal of neurochemistry》1997,69(2):721-728
Abstract: The role of oleic acid in the modulation of gap junction permeability was studied in cultured rat astrocytes by the scrape-loading/Lucifer yellow transfer technique. Incubation with oleic acid caused a dose-dependent inhibition of gap junction permeability by 79.5% at 50 µ M , and no further inhibition was observed by increasing the oleic acid concentration to 100 µ M . The oleic acid-mediated inhibition of gap junction permeability was reversible and was prevented by bovine serum albumin. The potency of oleic acid-related compounds in inhibiting gap junction permeability was arachidonic acid > oleic acid > oleyl alcohol > palmitoleic acid > stearic acid > octanol > caprylic acid > palmitic acid > methyloleyl ester. Oleic acid and arachidonic acid, but not methyloleyl ester, increased glucose uptake by astrocytes. Neither oleic acid nor arachidonic acid increased glucose uptake in the poorly coupled glioma C6 cells. These results support that the inhibition of gap junction permeability is associated with the increase in glucose uptake. We suggest that oleic acid may be a physiological mediator of the transduction pathway leading to the inhibition of intercellular communication. 相似文献
106.
Maira Oropeza Palmira Guevara Eva de García José Luis Ramírez 《Plant Molecular Biology Reporter》1995,13(2):182-191
Somaclonal variants resistant to sugarcane mosaic virus (SCMV) were obtained from susceptible sugarcane cv PR62258 through
somatic embryogenesis by increasing the number of subcultures of the embryogenic callus tissue in MS medium with 3 mg/L 2,4-dichlorophenoxyacetic
acid. Transfers were made at 30-day intervals for 1, 2 or 3 subcultures. Two somaclones, namely AT626 and BT627, were selected
by their resistance to SCMV. These subclones have maintained the resistance trait over seven years of testing in the field.
In this report we identified the somaclonal SCMV resistant variants from the maternal line and the nonresistant somaclones,
using the RAPD technique. 相似文献
107.
José Luis López-Ribot Deborah A. Cortlandt David C. Straus K. John Morrow W. LaJean Chaffin 《Mycopathologia》1995,132(2):87-93
We have previously described a monoclonal antibody, MAb DC3:H10, which recognized an epitope preferentially expressed on the surface ofCandida albicans germ tubes. In the present study we examined the MAb-reactive material further. Immunoblot analysis of the material purified partially by Sephadex G-200 and DEAE-Sephacel chromatography reacted with antibodies to theC. albicans C3d receptor (CR2). In an ELISA, MAb DC3:H10 captured antigen that was recognized by both anti-CR2 and anti-mp58 fibrinogen binding mannoprotein polyclonal antibodies. The MAb DC3:H10 failed to compete with either of these antisera in an ELISA. Indirect immunofluo-rescence (IIF) analysis showed differences in surface distribution for the MAb DC3:H10, the CR2, and the mp 58 epitopes. Dual labeling IIF experiments showed MAb DC3:H10 binding to be unaffected by binding of fibrinogen or anti-mp58 antibody. However, the binding patterns of MAb DC3:H10 were modified in the presence of anti-CR2 antibody, suggesting a complex interaction between these cell wall components. 相似文献
108.
Summary Conformational preferences of secretin as a model peptide have been analyzed by CD and IR spectroscopy in reverse micelles of AOT/isooctane/water and compared to those in aqueous TFE, in SDS micelles and in DMPG vesicles. Among the systems examined, reverse micelles and phospholipid vesicles displayed almost identical conformational equilibria. Very high lipid-to-peptide ratios can be obtained in reverse micelles with full retention of optical transparency, even at millimolar peptide concentrations, thus indicating this system to be an interesting mimic of cell membrane environments for spectroscopic analysis of bioactive peptide conformations.Abbreviations TFE
trifluoroethanol
- SDS
sodium dodecyl sulfate
- DMPG
dimyristoylphosphatidylglycerol
- AOT
bis(2-ethylhexyl)sulfosuccinate
- CMC
critical micellar concentration
- VIP
vasoactive intestinal peptide 相似文献
109.
110.
Characterization and regulation of the expression of FatB, an iron transport protein encoded by the pJM1 virulence plasmid 总被引:7,自引:0,他引:7
Luis A. Actis Marcelo E. Tolmasky Lidia M. Crosa Jorge H. Crosa 《Molecular microbiology》1995,17(1):197-204
The pJM1-encoded genes fatDCBA are essential for iron acquisition via the siderophore anguibactin. Sequence analysis indicated that the open reading frame corresponding to the fatB gene possesses domains that are characteristic of periplasmic proteins that bind the ferric siderophore. In this work, a monospecific antiserum against an oligopeptide containing the last 27 amino acids of the carboxy-terminal region from this open reading frame was used to demonstrate that fatB encodes a 35 kDa protein that is essential for iron transport. By using this antibody we were able to demonstrate that expression of the fatB gene is negatively regulated by the Fur protein at high iron concentrations. Conversely, its expression was positively regulated by the combined action of the AngR protein and products of the TAF region. FatB, the product of the fatB gene, is isolated with the membrane fraction. In accordance with these findings is the fact that the first 23 amino acid residues of this protein have the properties of a lipoprotein signal sequence. The lipoprotein nature of FatB is supported by the fact that treatment of Vibrio anguillarum cells with globomycin, an inhibitor of the lipoprotein signal peptidase, results in the accumulation of a 38 kDa pro-FatB precursor protein. 相似文献