Abstract:
:The effect of carlorie intake on the development of spontaneous mammary tumors in virgin C3H mice was studied. Only about 10% of the mice fed a low-calorie diet [10 kcal/day (1 kcal = 4.184 kJ)] since weaning developed mammary tumors, compared to about 60% of those mice that were reared on high-calorie diets (16 kcal/day or lab chow ad lib). In order to understand the mechanism by which a low-calorie diet decreases the occurrence of mammary tumors in mice, we compared the sex cycle, the amounts of circulating thyroid-stimulating hormone (thyrotropin), growth hormone, and prolactin, the production of type A and B virus particles in the mammary glands, and the morphology of the mammary glands of mice fed low- and high-calorie diets. The amount of serum prolactin and the synthesis of type A and B particles in mammary tissues of mice fed a low-calorie diet was markedly decreased compared to those of age-matched mice fed high-calorie diets. In addition, in young mice fed a low-calorie diet, there were fewer mammary alveolar lesions than in mice fed a high-calorie diet, although the size of the lesions was similar. However, in older mice fed the high-calorie diet, the number and size of these lesions were greater than in the mice raised on the low-calorie diet. The other factors that we studied were not affected by calorie restriction. Our findings suggest that the reduction in serum prolactin level, mammary tumor virus production, and proliferation of mammary alveolar lesions associated with dietary calorie restriction is responsible for lowering the incidence of mammary tumors in mice.
journal_name
Proc Natl Acad Sci U S Aauthors
Sarkar NH,Fernandes G,Telang NT,Kourides IA,Good RAdoi
10.1073/pnas.79.24.7758subject
Has Abstractpub_date
1982-12-01 00:00:00pages
7758-62issue
24eissn
0027-8424issn
1091-6490journal_volume
79pub_type
杂志文章abstract::Human chorionic gonadotropin (hCG) preparations contain activity against HIV type 1 (HIV-1). However, there has been controversy about whether some biological activities of hCG beta-subunit (hCGbeta) preparations are caused by the beta-subunit itself or other proteins present in the preparations. We report here the pu...
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.96.6.2678
更新日期:1999-03-16 00:00:00
abstract::Invariant natural killer T (iNKT) cells recognize lipid antigens presented by CD1d and play a central role in regulating immunity and inflammation in peripheral tissues. However, the mechanisms which govern iNKT cell homeostasis after thymic emigration are incompletely understood. Here we demonstrate that microsomal t...
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.1701428114
更新日期:2017-09-26 00:00:00
abstract::A novel type I transmembrane protein of COPI-coated vesicles, p23, has been demonstrated to be localized mainly to the Golgi complex. This protein and p24, another member of the p24 family, have been shown to bind coatomer via their short cytoplasmic tails. Here we demonstrate that p23 continuously cycles through 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.94.21.11393
更新日期:1997-10-14 00:00:00
abstract::We describe a functional profiling strategy to identify and characterize subtypes of neurons present in a peripheral ganglion, which should be extendable to neurons in the CNS. In this study, dissociated dorsal-root ganglion neurons from mice were exposed to various pharmacological agents (challenge compounds), while ...
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.1118833109
更新日期:2012-01-31 00:00:00
abstract::In vitro data show that the adenomatous polyposis coli (APC) protein associates with the mitotic spindle and that mouse embryonic stem cells with biallelic Apc mutations are karyotypically unstable. These findings led to suggestions that APC acts in chromosomal segregation and that APC inactivation leads to chromosoma...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::What determines the firing rate of cortical neurons in the absence of external sensory input or motor behavior, such as during sleep? Here we report that, in a familiar environment, the discharge frequency of simultaneously recorded individual CA1 pyramidal neurons and the coactivation of cell pairs remain highly corr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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abstract::The use of fluorescent probes to give continuous readouts of the structural states of mitochondrial membranes during energy coupling seems a logical extension of their use in the study of protein structural changes. A clear correlation of the probes' fluorescence characteristics with the acquisition of energy coupling...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1970-10-01 00:00:00
abstract::A striking feature of the human genome is the dearth of CpG dinucleotides (CpGs) interrupted occasionally by CpG islands (CGIs), regions with relatively high content of the dinucleotide. CGIs are generally associated with promoters; genes, whose promoters are especially rich in CpG sequences, tend to be expressed in m...
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.0510310103
更新日期:2006-01-31 00:00:00
abstract::Phytochrome photoreceptors control plant growth, development, and the shade avoidance response that limits crop yield in high-density agricultural plantings. Cyanobacteriochromes (CBCRs) are distantly related photosensory proteins that control cyanobacterial metabolism and behavior in response to light. Photoreceptors...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::The nucleic acid sequence of the 3' region of human T-cell leukemia virus type II (HTLV-II) proviral DNA was determined using a HTLV-II proviral clone that could be recovered as infectious, transforming virus. The sequence data indicate a region of unknown function of approximately equal to 1.6 kilobase pairs in the 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.81.21.6657
更新日期:1984-11-01 00:00:00
abstract::High molecular weight proteins extracted from the walking nerves of the shore crab (Carcinus maenas) exhibit a cycle of phosphorylation-dephosphorylation that is influenced by neurotropic compounds and inorganic ions. The net phosphorylation state of the proteins is increased in the presence of K+ ions and decreased w...
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.77.2.812
更新日期:1980-02-01 00:00:00
abstract::An effective plant alkaloid chemical defense requires a variety of transport processes, but few alkaloid transporters have been characterized at the molecular level. Previously, a gene fragment encoding a putative plasma membrane proton symporter was isolated, because it was coordinately regulated with several nicotin...
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.1108620108
更新日期:2011-11-01 00:00:00
abstract::Colocalization of proteins that are part of the same signal transduction pathway via compartmentalization, scaffold, or anchor proteins is an essential aspect of the signal transduction system in eukaryotic cells. If interaction must occur via free diffusion, then the spatial separation between the sources of the two ...
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.0401314101
更新日期:2004-04-27 00:00:00
abstract::Whether the regulatory protein of an inducible operon for a catabolic pathway is a positive or a negative element in the control of expression is correlated with the frequent or infrequent presence, respectively, of the system's substrate in the natural environment. ...
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.71.6.2453
更新日期:1974-06-01 00:00:00
abstract::The ability of the isolated perfused rat liver to differentiate between chylomicrons and remnants with either high or low apoprotein E:C ratios was investigated. Remnants were prepared in hepatectomized rats injected with chylomicrons double-labeled with [3H]cholesterol and 14C-labeled fatty acids. By densitometric sc...
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.81.18.5863
更新日期:1984-09-01 00:00:00
abstract::Studies by several investigators have shown that 12-0-tetradecanoylphorbol-13-acetate (TPA) is an extraordinarily potent stimulator of differentiation of cultured human promyelocytic leukemia cells in vitro. In the present study, TPA was administered to humans by i.v. infusion without irreversible toxicity, and it was...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 临床试验,杂志文章
doi:10.1073/pnas.95.9.5357
更新日期:1998-04-28 00:00:00
abstract::The molecular basis of bacterial cell morphogenesis remains largely an open question. Here we discover a morphogenic protein, RodZ, which is widely conserved across the bacterial kingdom. In Caulobacter crescentus, RodZ is essential for viability and is involved in all aspects of this organism's complex morphology. De...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2009-01-27 00:00:00
abstract::It has been proposed that extensive wildfires occurred after the Cretaceous-Tertiary (K-T) impact event. An abundance of soot and pyrosynthetic polycyclic aromatic hydrocarbons (pPAHs) in marine K-T boundary impact rocks (BIRs) have been considered support for this hypothesis. However, nonmarine K-T BIRs, from across ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::Adaptation to hypoxia is mediated by transactivation of hypoxia-responsive genes by hypoxia-inducible factor-1 (HIF-1) in complex with the CBP and p300 transcriptional coactivators. We report the solution structure of the cysteine/histidine-rich 1 (CH1) domain of p300 bound to the C-terminal transactivation domain of ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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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.1936192100
更新日期:2003-11-25 00:00:00
abstract::Litter size and mammary number in the mammalian order Rodentia show a significant positive correlation. Mean litter size is typically one-half the number of available mammaries, while maximum litter size approximates mammary number. Similar relationships are found in the families Muridae, Cricetidae, and Sciuridae. Th...
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.83.13.4828
更新日期:1986-07-01 00:00:00
abstract::Histones play a crucial role in the organization of DNA in the nucleus, but their presence can prevent interactions with DNA binding proteins responsible for repair of DNA damage. Uracil is an abundant mutagenic lesion recognized by uracil DNA glycosylase (UDG) in the first step of base excision repair (BER). In nucle...
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.0914443107
更新日期:2010-03-09 00:00:00
abstract::It has been a long-sought goal of quantum simulation to find answers to outstanding questions in condensed-matter physics. A famous example is finding the ground state and the excitations of the two-dimensional (2D) Hubbard model with strong repulsion below half-filling. This system is a doped antiferromagnet and is o...
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.2004268117
更新日期:2020-10-20 00:00:00
abstract::We show in climate model experiments that large-scale afforestation in northern mid-latitudes warms the Northern Hemisphere and alters global circulation patterns. An expansion of dark forests increases the absorption of solar energy and increases surface temperature, particularly in regions where the land surface is ...
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.1116706108
更新日期:2012-01-17 00:00:00
abstract::Molecular weights of the isolated proteins from the 30S and 50S ribosomal subunits of Escherichia coli were determined by two independent methods: polyacrylamide gel electrophoresis with sodium dodecylsulphate and equilibrium sedimentation. The values for the molecular weights determined by gel electrophoresis range f...
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.67.4.1909
更新日期:1970-12-01 00:00:00
abstract::Fermions need to satisfy the Pauli exclusion principle: no two can be in the same state. This restriction is most compactly expressed in a second quantization formalism by the requirement that the creation and annihilation operators of the electrons satisfy anticommutation relations. The usual classical limit of quant...
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.97.5.1965
更新日期:2000-02-29 00:00:00
abstract::Human neutrophils respond to chemoattractants, resulting in their accumulation at an inflammatory site. Chemoattractants such as the C5a peptide, derived from the C5 complement factor, bind to inhibitory guanine nucleotide binding protein (Gi)-coupled seven membrane-spanning receptors expressed in neutrophils. C5a rec...
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.91.19.9190
更新日期:1994-09-13 00:00:00
abstract::Hydrogen atoms constitute about half of all atoms in proteins and play a critical role in enzyme mechanisms and macromolecular and solvent structure. Hydrogen atom positions can readily be determined by neutron diffraction, and as such, neutron diffraction is an invaluable tool for elucidating molecular mechanisms. Jo...
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.0807842106
更新日期:2009-01-20 00:00:00
abstract::Prion diseases are characterized by an accumulation of PrP(Sc), a misfolded isoform of the normal cellular prion protein, PrP(C). We previously reported the bioactivity of acridine-based compounds against PrP(Sc) replication in scrapie-infected neuroblastoma cells and now report the improved potency of bis-acridine co...
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.2627988100
更新日期:2003-03-18 00:00:00