Abstract:
:We have earlier reported conditions that support the axenic development in vitro of a complete asexual erythrocytic cycle of Plasmodium falciparum. Up to 30% of merozoites showed initial differentiation into trophic forms (rings) viable at 14 hr. However, only approximately 1% of the merozoites would develop further into trophozoites and early schizonts viable at 36 hr. In efforts to increase the number of late stage parasites, we have now found a significant favorable effect of the addition of erythrocyte ghosts. Doubling the quantity of erythrocyte membrane in the erythrocyte sonicate medium resulted in approximate doubling of the number of trophozoites and early schizonts. These results indicate that components of the erythrocyte membrane are essential for the complete development of the erythrocytic cycle.
journal_name
Proc Natl Acad Sci U S Aauthors
Williams JH,Gill GS,Trager Wdoi
10.1073/pnas.92.2.566subject
Has Abstractpub_date
1995-01-17 00:00:00pages
566-8issue
2eissn
0027-8424issn
1091-6490journal_volume
92pub_type
杂志文章abstract::Bacteriorhodopsin from Halobacterium halobium has been solubilized in the nonionic detergent Triton X-100. The circular dichroic spectrum and hydrodynamic properties indicate that the structure of this protein in the detergent is not significantly altered from that of the native membrane-bound form. Bacteriorhodopsin ...
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.74.7.2803
更新日期:1977-07-01 00:00:00
abstract::Habitat loss and disease are main drivers of global amphibian declines, yet the interaction between them remains largely unexplored. Here we show that paradoxically, habitat loss is negatively associated with occurrence, prevalence, and infection intensity of the chytrid fungus Batrachochytrium dendrobatidis (Bd) in 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.1014497108
更新日期:2011-06-14 00:00:00
abstract::A polypeptide was purified from rat hypothalamic extracts on the basis of its high intrinsic activity to release corticotropin (ACTH) from cultured rat anterior pituitary cells and its immunoactivity in a radioimmunoassay directed against the NH2 terminus (residues 4-20) of ovine hypothalamic corticotropin-releasing 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.80.15.4851
更新日期:1983-08-01 00:00:00
abstract::We have analyzed the patterns of positive and negative selection of thymocytes expressing the T cell antigen receptor (TCR) from the D10.G4.1 T cell clone. This TCR confers reactivity to several non-self MHC class II alleles with a remarkably broad range of avidities. Therefore, negative selection can be studied when ...
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.102182499
更新日期:2002-05-14 00:00:00
abstract::Commercial hydrogen production by electrocatalytic water splitting will benefit from the realization of more efficient and less expensive catalysts compared with noble metal catalysts, especially for the oxygen evolution reaction, which requires a current density of 500 mA/cm2 at an overpotential below 300 mV with lon...
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.1701562114
更新日期:2017-05-30 00:00:00
abstract::Chromosomal RNA was isolated from several rat tissues by a new technique. It is shown by RNA-DNA hybridization that each tissue contains a distinct population of chromosomal RNA sequences. This finding is compatible with the proposal that chromosomal RNA is involved in the process of gene activation. ...
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.68.11.2652
更新日期:1971-11-01 00:00:00
abstract::Treatment of full-thickness damage to hyaline cartilage is hampered by the limited availability of autologous healthy cartilage and the lengthy, cost-prohibitive cell isolation and expansion steps associated with autologous cartilage implantation (ACI). Here we report a strategy for de novo engineering of ectopic auto...
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.0907774107
更新日期:2010-02-23 00:00:00
abstract::Perceptual decisions are better when they take uncertainty into account. Uncertainty arises not only from the properties of sensory input but also from cognitive sources, such as different levels of attention. However, it is unknown whether humans appropriately adjust for such cognitive sources of uncertainty during p...
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.1717720115
更新日期:2018-10-23 00:00:00
abstract::A serum-free culture of dissociated neurons from embryonic rat hippocampus has been established as a rapid and quantitative in vitro test system for neurotrophic signals in the mammalian brain. By means of this cell culture bioassay, a novel low molecular weight neurotrophic factor (NTF) could be identified. NTF is es...
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.81.4.1248
更新日期:1984-02-01 00:00:00
abstract::The use of matching variable number of tandem repeat (VNTR) profiles to link suspects with crimes is potentially very powerful, but it has been quite controversial. Initial debate over laboratory procedures has largely given way to debate over the statistical and population genetic issues involved in calculating the f...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.89.24.11654
更新日期:1992-12-15 00:00:00
abstract::In a previous study, we found that human neural stem cells (HNSCs) exposed to high concentrations of secreted amyloid-precursor protein (sAPP) in vitro differentiated into mainly astrocytes, suggesting that pathological alterations in APP processing during neurodegenerative conditions such as Alzheimer's disease (AD) ...
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.0705346104
更新日期:2007-07-24 00:00:00
abstract::Initiation of adenovirus DNA replication in vitro occurs on a linearized plasmid DNA containing 3,327 base pairs of the adenovirus terminal sequence. Various deletions have been constructed in the plasmid DNA and their template activities examined. Deletions from an internal restriction enzyme cleavage site that retai...
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.80.21.6446
更新日期:1983-11-01 00:00:00
abstract::Vertebrates, from zebra fish to humans, have an innate immune recognition of many bacterial flagellins. This involves a conserved eight-amino acid epitope in flagellin recognized by the Toll-like receptor 5 (TLR5). Several important human pathogens, such as Helicobacter pylori and Campylobacter jejuni, have escaped TL...
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.2010996117
更新日期:2020-07-21 00:00:00
abstract::Landscape-scale reconstructions of ancient environments within the cradle of humanity may reveal insights into the relationship between early hominins and the changing resources around them. Many studies of Olduvai Gorge during Pliocene-Pleistocene times have revealed the presence of precession-driven wet-dry cycles 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.2004532117
更新日期:2020-10-06 00:00:00
abstract::We solve a discrete version of the classic Plateau problem, which asks for a minimal surface spanning a given curve. Our algorithm is based on a network-flow formulation that finds minimal slabs, intuitively corresponding to minimal "surfaces" of prescribed thickness. We let the slab thickness approach zero in order 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.89.19.9235
更新日期:1992-10-01 00:00:00
abstract::Simian virus 40 (SV40)-transformed hamster cells were relatively resistant to the lytic effect of activated macrophages from animals with chronic intracellular infections. Conversely, SV40-transformed mouse and rat cells and adenovirus 2-transformed hamster cells were highly susceptible to destruction by tumoricidal 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.77.11.6773
更新日期:1980-11-01 00:00:00
abstract::After males of Lasioglossum zephyrum (Hymenoptera: Halictidae) have first been exposed to a conspecific female, the attractiveness of a second female diminishes with increasing genealogical relationship between the two females. The most parsimonious explanation for this is a polygenically controlled female sex pheromo...
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.80.14.4551
更新日期:1983-07-01 00:00:00
abstract::The pineal organ of the lizard Anolis carolinensis can be maintained for up to 10 days in superfused organ culture. During this time it synthesizes and releases melatonin into the medium flowing slowly over it. Collection of timed aliquots of medium and subsequent analysis for melatonin by radioimmunoassay reveal circ...
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.80.19.6119
更新日期:1983-10-01 00:00:00
abstract::The production of hybridomas between immunologically activated T cells and malignant T-cell lines offers a potentially unlimited source of soluble T-cell-derived products. Recently, human T-T hybrids have been described; however, their use has been hampered by slow growth and chromosomal instability due at least in pa...
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.79.23.7484
更新日期:1982-12-01 00:00:00
abstract::Biotin carboxylase [biotin-carboxyl-carrier-protein:carbon-dioxide ligase (ADP-forming), EC 6.3.4.14] is the enzyme mediating the first step of the acetyl-CoA carboxylase [acetyl-CoA:carbon-dioxide ligase (ADP-forming), EC 6.4.1.2] reaction. We screened an Escherichia coli DNA library and a DNA fragment carrying the b...
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.88.21.9730
更新日期:1991-11-01 00:00:00
abstract::The mitochondrial contact site and cristae organizing system (MICOS) is a multisubunit protein complex that is essential for the proper architecture of the mitochondrial inner membrane. MICOS plays a key role in establishing and maintaining crista junctions, tubular or slit-like structures that connect the cristae mem...
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.2009364117
更新日期:2020-08-25 00:00:00
abstract::To study the structure and function of the gene for parathyroid hormone, we obtained recombinant plasmids containing bovine parathyroid hormone cDNA. The nucleotide sequence at the 5' terminus (relative to the sense strand) of the cDNA insert in a recombinant plasmid, pPTHi4, was different from that previously reporte...
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.78.7.4073
更新日期:1981-07-01 00:00:00
abstract::As 3D culture has become central to investigation of tissue biology, mammary epithelial organoids have emerged as powerful tools for investigation of epithelial cell polarization and carcinogenesis. However, most current protocols start from single cells suspended in Matrigel, which can also restrict cell differentiat...
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.1702372116
更新日期:2019-06-04 00:00:00
abstract::Pharmacological treatments designed to reactivate fetal γ-globin can lead to an effective and successful clinical outcome in patients with hemoglobinopathies. However, new approaches remain highly desired because such treatments are not equally effective for all patients, and toxicity issues remain. We have taken a sy...
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.0912896107
更新日期:2010-09-28 00:00:00
abstract::A scientist may publish tens or hundreds of papers over a career, but these contributions are not evenly spaced in time. Sixty years of studies on career productivity patterns in a variety of fields suggest an intuitive and universal pattern: Productivity tends to rise rapidly to an early peak and then gradually decli...
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.1702121114
更新日期:2017-10-31 00:00:00
abstract::Phosducin is a soluble phosphoprotein found in retinal photoreceptor cells and in the pineal gland. It binds to the beta gamma subunits of guanine nucleotide-binding proteins (G proteins) (G beta gamma) and may regulate G-protein function. In this study, the ability of specific regions of phosducin to bind G beta gamm...
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.92.6.2086
更新日期:1995-03-14 00:00:00
abstract::Finding regions of the genome that are significantly recurrent in noisy data are a common but difficult problem in present day computational biology. Cores of recurrent events (CORE) is a computational approach to solving this problem that is based on a formalized notion by which "core" intervals explain the observed ...
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.1306909110
更新日期:2013-06-18 00:00:00
abstract::Immigration and demographic change have become highly salient in American politics, partly because of the 2016 campaign of Donald Trump. Previous research indicates that local influxes of immigrants or unfamiliar ethnic groups can generate threatened responses, but has either focused on nonelectoral outcomes or analyz...
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.1909202116
更新日期:2019-12-10 00:00:00
abstract::It has long been recognized that the T-cell compartment has more CD4 helper than CD8 cytotoxic T cells, and this is most evident looking at T-cell development in the thymus. However, it remains unknown how thymocyte development so favors CD4 lineage development. To identify the basis of this asymmetry, we analyzed dev...
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.1304859110
更新日期:2013-07-30 00:00:00
abstract::Electron microscopy is arguably the most powerful tool for spatial imaging of structures. As such, 2D and 3D microscopies provide static structures with subnanometer and increasingly with angstrom-scale spatial resolution. Here we report the development of 4D ultrafast electron microscopy, whose capability imparts ano...
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.0502607102
更新日期:2005-05-17 00:00:00