Abstract:
:Etioplasts isolated from barley leaves and purified on a Sephadex G-50 (coarse) column were characterized by electron microscopy and nucleic acid analysis. The majority of etioplasts retained an intact outer envelope, and contamination by other fragments was extremely low. The level of gibberellin-like substances extractable from intact etioplast suspensions was enhanced within 5 min of the termination of a saturating red irradiation, and the response was far-red reversible. Ultra-sonication caused a 3-fold increase in extractable activity both in dark control suspension and suspensions treated with red light. It is concluded that phytochrome, as a function of its interconversions, probably causes the transport of gibberellin from inside the etioplast into the surrounding medium. This leads to increased production of active gibberellins, possibly by release of feedback control of late steps of the biosynthetic pathway. Dual wavelength difference spectrophotometry has demonstrated the presence of a proportion of total cellular phytochrome within the etioplast.
journal_name
Proc Natl Acad Sci U S Aauthors
Evans A,Smith Hdoi
10.1073/pnas.73.1.138subject
Has Abstractpub_date
1976-01-01 00:00:00pages
138-42issue
1eissn
0027-8424issn
1091-6490journal_volume
73pub_type
杂志文章abstract::The growth of colloidal metal nanocrystals typically involves an autocatalytic process, in which the salt precursor adsorbs onto the surface of a growing nanocrystal, followed by chemical reduction to atoms for their incorporation into the nanocrystal. Despite its universal role in the synthesis of colloidal nanocryst...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1713907114
更新日期:2017-12-26 00:00:00
abstract::The androgen receptor (AR) binds to androgen response elements and regulates target genes via a mechanism involving coregulators. Here we demonstrate that the AR can interact with the testicular orphan receptor-4 (TR4) and function as a repressor to down-regulate the TR4 target genes by preventing the TR4 binding to i...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.26.14724
更新日期:1999-12-21 00:00:00
abstract::Three allelic variants of P-pilus-associated G-adhesins (lectins) with different cell-binding properties were recently described. Here we have analyzed Escherichia coli HB101 strains expressing the recombinant G-adhesin variants for their ability to agglutinate erythrocytes from various species as this relates to the ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.88.20.9340
更新日期:1991-10-15 00:00:00
abstract::Do negative feelings in general trigger addictive behavior, or do specific emotions play a stronger role? Testing these alternative accounts of emotion and decision making, we drew on the Appraisal Tendency Framework to predict that sadness, specifically, rather than negative mood, generally, would 1) increase craving...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1909888116
更新日期:2020-01-14 00:00:00
abstract::Synaptojanin 1 is a polyphosphoinositide phosphatase concentrated in presynaptic nerve terminals, where it dephosphorylates a pool of phosphatidylinositol 4,5-bisphosphate implicated in synaptic vesicle recycling. Like other proteins with a role in endocytosis, synaptojanin 1 undergoes constitutive phosphorylation in ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0307813100
更新日期:2004-01-13 00:00:00
abstract::The strikingly high incidence of obstructed labor due to the disproportion of fetal size and the mother's pelvic dimensions has puzzled evolutionary scientists for decades. Here we propose that these high rates are a direct consequence of the distinct characteristics of human obstetric selection. Neonatal size relativ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1612410113
更新日期:2016-12-20 00:00:00
abstract::Sheep antibodies directed against an AMP-bovine serum albumin conjugate exhibit highly specific binding toward AMP. These antibodies bind to the AMP moiety of adenylylated glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2] from Escherichia coli and to no other antigenic determinant on the prot...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.77.12.7410
更新日期:1980-12-01 00:00:00
abstract::Proteasomes are the multi-subunit protease thought to play a key role in the generation of peptides presented by major histocompatibility complex (MHC) class I molecules. When cells are stimulated with interferon gamma, two MHC-encoded subunits, low molecular mass polypeptide (LMP) 2 and LMP7, and the MECL1 subunit en...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.17.9096
更新日期:1996-08-20 00:00:00
abstract::Human liver alkaline phosphatase [ortho-phosphoric monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1] was purified, and some of its physical and chemical properties were examined and compared to those of human placental alkaline phosphatase. The results indicated a different peptide structure for each, based u...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.7.2201
更新日期:1976-07-01 00:00:00
abstract::That the yolk proteins (YPs), or vitellins, stored in the oocytes of insects are a nutritional store for subsequent embryogenesis has long been assumed. Exhaustive data base searching programs revealed highly significant sequence similarity between the three YPs of Drosophila melanogaster and part of the triacylglycer...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.5.1554
更新日期:1988-03-01 00:00:00
abstract::The live cold-adapted (ca) A/AA/6/60 influenza vaccine is being commercially developed for worldwide use in children and is being used as a model for other live vaccines. Although it has been proven safe and immunogenic, the molecular basis of cold adaptation has never been determined. To identify sequence changes res...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.13.6032
更新日期:1993-07-01 00:00:00
abstract::We used integrin alphaLbeta2 heterodimers containing I domains locked open (active) or closed (inactive) with disulfide bonds to investigate regulatory interactions among domains in integrins. mAbs to the alphaL I domain and beta2 I-like domain inhibit adhesion of wild-type alphaLbeta2 to intercellular adhesion molecu...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.041618598
更新日期:2001-02-27 00:00:00
abstract::Ca(2+)-sensitive kinases are thought to play a role in long-term potentiation (LTP). To test the involvement of Ca2+/calmodulin-dependent kinase II (CaM-K II), truncated, constitutively active form of this kinase was directly injected into CA1 hippocampal pyramidal cells. Inclusion of CaM-K II in the recording pipette...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.24.11175
更新日期:1995-11-21 00:00:00
abstract::Mechanism of enzymatic conversion of a fatty acid to the corresponding alkane by the loss of the carboxyl carbon was investigated with particulate preparations from Pisum sativum. A heavy particulate preparation (sp. gr., 1.30 g/cm3) isolated by two density-gradient centrifugation steps catalyzed conversion of octadec...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.21.6613
更新日期:1984-11-01 00:00:00
abstract::We have carried out a study of large malignant skin tumors (squamous cell carcinomas) and other lesions in hairless mice (groups of 38-45) intermittently exposed to ultraviolet light over a period of 15 weeks, beginning when the mice were about 10 weeks old. The several groups were given a standard diet with 0%, 0.3%,...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.79.23.7532
更新日期:1982-12-01 00:00:00
abstract::The yeast fatty acid synthase (M(r) = 2.5 x 10(6)) is organized in an alpha 6 beta 6 complex. In these studies, the synthase structure has been examined by negative-stain and cryo-electron microscopy. Side and end views of the structure indicate that the molecule, shaped similar to a prolate ellipsoid, has a high-dens...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.14.6585
更新日期:1992-07-15 00:00:00
abstract::Following carcinogen exposure in vitro, normal rat tracheal epithelial cells are transformed in a multistage process in which the cultured cells become immortal and, ultimately, neoplastic. Five cell lines derived from tumors produced by neoplastically transformed rat tracheal epithelial cells were examined for the ex...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.7.1804
更新日期:1987-04-01 00:00:00
abstract::Mitochondrial function and ambulatory activity were monitored after feeding old rats acetyl-L-carnitine (ALCAR). Young (3-5 mo) and old (22-28 mo) rats were given a 1.5% (wt/vol) solution of ALCAR in their drinking water for 1 mo, were sacrificed, and their liver parenchymal cells were isolated. ALCAR supplementation ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.16.9562
更新日期:1998-08-04 00:00:00
abstract::Because most human squamous carcinoma cell lines of the aerodigestive and genital tracts are refractory to the antiproliferative action of transforming growth factor beta 1 (TGF beta 1) in vitro, we have begun to identify the causes for resistance of squamous carcinoma cell lines to TGF beta 1 by using somatic cell ge...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.13.6280
更新日期:1993-07-01 00:00:00
abstract::In this model gravitation results from the emission and absorption of quanta (gravitons) that are scattered a few times in crossing a typical galaxy. Many features of the universe can be explained in terms of this model, although theoretical justification for the scattering of gravitons is lacking. Gravitons follow a ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.9.4086
更新日期:1992-05-01 00:00:00
abstract::Antisense oligodeoxyribonucleotides targeted to the epidermal growth factor (EGF) receptor were encapsulated into liposomes linked to folate via a polyethylene glycol spacer (folate-PEG-liposomes) and efficiently delivered into cultured KB cells via folate receptor-mediated endocytosis. The oligonucleotides were a pho...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.8.3318
更新日期:1995-04-11 00:00:00
abstract::p300 acetylates and activates the tumor suppressor p53 after DNA damage. Here, we show that MDM2, a negative-feedback regulator of p53, inhibited p300-mediated p53 acetylation by complexing with these two proteins. First, we purified a p300-MDM2-p53 protein complex from HeLa nuclear extracts, which was inactive in p53...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.97.23.12547
更新日期:2000-11-07 00:00:00
abstract::The regulation of initiation of DNA replication is crucial to ensure that the genome is replicated only once per cell cycle. In the Gram-positive bacterium Bacillus subtilis, the function of the YabA protein in initiation control was assigned based on its interaction with the DnaA initiator and the DnaN sliding clamp ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0506914103
更新日期:2006-02-14 00:00:00
abstract::We have investigated whether glycosylation of membrane glycoproteins is a determinant of the site of maturation of enveloped viruses in Madin-Darby canine kidney (MDCK) cells. In MDCK cell monolayers, vesicular stomatitis virus buds exclusively from the basal or lateral plasma membranes and contains a sialylated glyco...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.76.12.6430
更新日期:1979-12-01 00:00:00
abstract::Because xenon NMR is highly sensitive to the local environment, laser-polarized xenon could be a unique probe of living tissues. Realization of clinical and medical science applications beyond lung airspace imaging requires methods of efficient delivery of laser-polarized xenon to tissues, because of the short spin-la...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.26.14725
更新日期:1997-12-23 00:00:00
abstract::Tolerance and resistance provide hosts with two distinct defense strategies against parasitism. In resistance the hosts "fight" the parasite directly, whereas in tolerance the hosts fight the disease by ameliorating the damage that infection causes. There is increasing recognition that the two mechanisms may exhibit v...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0809558105
更新日期:2008-12-30 00:00:00
abstract::Modeling studies of terrestrial extrasolar planetary climates are now including the effects of ocean circulation due to a recognition of the importance of oceans for climate; indeed, the peak equator-pole ocean heat transport on Earth peaks at almost half that of the atmosphere. However, such studies have made the ass...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1522034113
更新日期:2016-04-19 00:00:00
abstract::Loss of the tumor suppressor, PTEN, is one of the most common findings in prostate cancer (PCa). This loss leads to overactive Akt signaling, which is correlated with increased metastasis and androgen independence. However, another tumor suppressor, inositol-polyphosphate 4-phosphatase type II (INPP4B), can partially ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.2007160117
更新日期:2020-10-20 00:00:00
abstract::Selection is widely accepted as the principal force shaping phenotypic variation within populations. Its importance in speciation and macroevolution has been questioned, however, because phenotypic differences between species or higher taxa sometimes appear to be nonadaptive. Here, we use the quantitative trait locus ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.192360899
更新日期:2002-09-17 00:00:00
abstract::Light emission produced by the reversible collapse of a cavity in a dielectric medium is given an initial, simplified treatment. The agreement between planar and spherical shapes indicates the volume nature of the effect. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.3.958
更新日期:1993-02-01 00:00:00