Abstract:
:The surface layer of the oceans and other aquatic environments contains many bacteria that range in activity, from dormant cells to those with high rates of metabolism. However, little experimental evidence exists about the activity of specific bacterial taxa, especially rare ones. Here we explore the relationship between abundance and activity by documenting changes in abundance over time and by examining the ratio of 16S rRNA to rRNA genes (rDNA) of individual bacterial taxa. The V1-V2 region of 16S rRNA and rDNA was analyzed by tag pyrosequencing in a 3-y study of surface waters off the Delaware coast. Over half of the bacterial taxa actively cycled between abundant and rare, whereas about 12% always remained rare and potentially inactive. There was a significant correlation between the relative abundance of 16S rRNA and the relative abundance of 16S rDNA for most individual taxa. However, 16S rRNA:rDNA ratios were significantly higher in about 20% of the taxa when they were rare than when abundant. Relationships between 16S rRNA and rDNA frequencies were confirmed for five taxa by quantitative PCR. Our findings suggest that though abundance follows activity in the majority of the taxa, a significant portion of the rare community is active, with growth rates that decrease as abundance increases.
journal_name
Proc Natl Acad Sci U S Aauthors
Campbell BJ,Yu L,Heidelberg JF,Kirchman DLdoi
10.1073/pnas.1101405108subject
Has Abstractpub_date
2011-08-02 00:00:00pages
12776-81issue
31eissn
0027-8424issn
1091-6490pii
1101405108journal_volume
108pub_type
杂志文章abstract::Mixed-metal oxides play a very important role in many areas of chemistry, physics, materials science, and geochemistry. Recently, there has been a strong interest in understanding phenomena associated with the deposition of oxide nanoparticles on the surface of a second (host) oxide. Here, scanning tunneling microscop...
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.0812604106
更新日期:2009-03-31 00:00:00
abstract::MS2 RNA binds at 0 degrees to 30S subunits from E. coli and, to a smaller extent, to those of a Pseudomonas species, as judged by filtration on nitrocellulose membranes; this mRNA does not bind to 30S subunits from Bacillus brevis or Caulobacter crescentus. Binding does not depend on the presence of initiation factors...
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.71.9.3611
更新日期:1974-09-01 00:00:00
abstract::Mutations at the mouse limb deformity (ld) locus result in defects of growth and patterning of the limb and kidney during embryonic development. The gene responsible for this phenotype is large and complex, with the capacity to generate a number of alternatively spliced messenger RNA transcripts encoding nuclear prote...
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.90.12.5554
更新日期:1993-06-15 00:00:00
abstract::The hydrodynamic properties of the detergent-solubilized, terminal membrane complex of serum complement components C5-C9 [C5b-9(m)] were studied to obtain an estimate of its molecular weight. In a solution of Triton X-100/deoxycholate, the protein complex binds 17% Triton X-100 and 11% deoxycholate by weight. The sedi...
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.78.3.1818
更新日期:1981-03-01 00:00:00
abstract::New important applications of copper metal, e.g., in the areas of hydrogen production, fuel cell operation, and spent nuclear fuel disposal, require accurate knowledge of the physical and chemical properties of stable and metastable copper compounds. Among the copper(I) compounds with oxygen and hydrogen, cuprous oxid...
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.1115834109
更新日期:2012-01-17 00:00:00
abstract::Charge transfer at metallo-molecular interfaces may be used to design multifunctional hybrids with an emergent magnetization that may offer an eco-friendly and tunable alternative to conventional magnets and devices. Here, we investigate the origin of the magnetism arising at these interfaces by using different techni...
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.1620216114
更新日期:2017-05-30 00:00:00
abstract::Appropriate hematopoietic stem cell (HSC) self-renewal reflects the tight regulation of cell cycle entry and lineage commitment. Here, we show that Id1, a dominant-negative regulator of E protein transcription factors, maintains HSC self-renewal by preserving the undifferentiated state. Id1-deficient HSCs show increas...
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.0607894104
更新日期:2007-01-23 00:00:00
abstract::The bacterial hibernating 100S ribosome is a poorly understood form of the dimeric 70S particle that has been linked to pathogenesis, translational repression, starvation responses, and ribosome turnover. In the opportunistic pathogen Staphylococcus aureus and most other bacteria, hibernation-promoting factor (HPF) ho...
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.1709588114
更新日期:2017-09-26 00:00:00
abstract::Mutations in the ATRX gene on the human X chromosome cause X-linked alpha-thalassemia and mental retardation. XY patients with deletions or mutations in this gene display varying degrees of sex reversal, implicating ATRX in the development of the human testis. To explore further the role of ATRX in mammalian sex diffe...
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.230424497
更新日期:2000-11-21 00:00:00
abstract::Regulatory mechanisms for tissue repair and regeneration within damaged tissue have been extensively studied. However, the systemic regulation of tissue repair remains poorly understood. To elucidate tissue nonautonomous control of repair process, it is essential to induce local damage, independent of genetic manipula...
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.1523681113
更新日期:2016-02-16 00:00:00
abstract::The multifunctional Ca2+/calmodulin-dependent protein kinase purified from rat brain cytosol undergoes an intramolecular self-phosphorylation or autophosphorylation. Autophosphorylation produces two strikingly different effects on kinase activity that are dependent on the level of ATP used in the reaction. At low but ...
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.83.24.9497
更新日期:1986-12-01 00:00:00
abstract::Corticotropin (ACTH) and melanotropin (MSH) peptides (melanocortins) are produced not only in the pituitary but also in the brain, with highest concentrations in the arcuate nucleus of the hypothalamus and the commisural nucleus of the solitary tract. We have identified a receptor for MSH and ACTH peptides that is spe...
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.90.19.8856
更新日期:1993-10-01 00:00:00
abstract::1,N(6)-Ethenoadenosine triphosphate (epsilon-ATP) has been found to be inactive as a substrate for firefly luciferase. However, chemically synthesized luciferyl-epsilonAMP is oxidized by luciferase and light is emitted. The color of the light is red in contrast to the normal yellow-green observed with luciferyladenyla...
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.70.6.1664
更新日期:1973-06-01 00:00:00
abstract::Biofilms formed by nontypeable Haemophilus influenzae (NTHI) are central to the chronicity, recurrence, and resistance to treatment of multiple human respiratory tract diseases including otitis media, chronic rhinosinusitis, and exacerbations of both cystic fibrosis and chronic obstructive pulmonary disease. Extracell...
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.1705508114
更新日期:2017-08-08 00:00:00
abstract::Relaxin is a member of the insulin family of polypeptides that is best known as a reproductive hormone. In an effort to elucidate the mechanism of action of relaxin we previously localized the specific binding sites of a 32P-labeled relaxin in the rat uterus and brain. These studies suggested that, in addition to its ...
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.89.6.2384
更新日期:1992-03-15 00:00:00
abstract::In many species that form pair bonds, males display to their mate after pair formation. These displays elevate the female's investment into the brood. This is a form of cooperation because without the display, female investment is reduced to levels that are suboptimal for both sexes. The presence of such displays is 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.1904138116
更新日期:2019-11-12 00:00:00
abstract::Class I major histocompatibility complex (MHC) antigens are confronted with an apparently insurmountable dilemma. Each should show a binding preference to a common enough variety of nonapeptides, so that one relevant nonapeptide can be found in at least every other viral protein to provoke a cytotoxic T-cell response....
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.89.10.4643
更新日期:1992-05-15 00:00:00
abstract::The role of spliced leader RNA (SL RNA) in trans-splicing in Caenorhabditis elegans has been studied through a combination of in vitro mutagenesis and in vivo complementation of rrs-1 mutant nematodes, which lack endogenous SL1 RNA. Three classes of mutant SL1 RNAs have been found-those that rescue the lethal phenotyp...
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.95.8.4235
更新日期:1998-04-14 00:00:00
abstract::Diffuse large B cell lymphomas (DLBCLs) often express BCL6, a transcriptional repressor required for the formation of normal germinal centers. In a subset of DLBCLs, BCL6 is deregulated by chromosomal translocations or aberrant somatic hypermutation; in other tumors, BCL6 expression may simply reflect germinal center ...
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.0611399104
更新日期:2007-02-27 00:00:00
abstract::The M2 protein of influenza A virus forms a transmembrane proton channel important for viral infection and replication. Amantadine blocks this channel, thus inhibiting viral replication. Elucidating the high-resolution structure of the M2 protein and its change upon amantadine binding is crucial for designing antivira...
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.0711500105
更新日期:2008-02-05 00:00:00
abstract::Recent analyses of high-throughput protein interaction data coupled with large-scale investigations of evolutionary properties of interaction networks have left some unanswered questions. To what extent do protein interactions act as constraints during evolution of the protein sequence? How does the type of interactio...
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.0502667102
更新日期:2005-08-02 00:00:00
abstract::Networks are widely used in the biological, physical, and social sciences as a concise mathematical representation of the topology of systems of interacting components. Understanding the structure of these networks is one of the outstanding challenges in the study of complex systems. Here we describe a general techniq...
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.0610537104
更新日期:2007-06-05 00:00:00
abstract::Neonatal ablation of the suprachiasmatic nucleus in the rat has two important consequences. First, the direct projection from the retina to the suprachiasmatic nucleus fails to develop and no other retinal projection to any hypothalamic nucleus is formed. Second, circadian rhythms in drinking and spontaneous locomotor...
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.75.12.6243
更新日期:1978-12-01 00:00:00
abstract::The bottom-up design of protein-based signaling networks is a key goal of synthetic biology; yet, it remains elusive due to our inability to tailor-make signal transducers and receptors that can be readily compiled into defined signaling networks. Here, we report a generic approach for the construction of protein-base...
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.1405220111
更新日期:2014-11-11 00:00:00
abstract::Mechanical signals are important influences on the development and morphology of higher plants. Using tobacco transformed with the Ca(2+)-sensitive luminescent protein aequorin, we recently reported the effects of mechanical signals of touch and wind on the luminescence and thus intracellular calcium of young seedling...
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.92.10.4124
更新日期:1995-05-09 00:00:00
abstract::The ability to modulate the collective properties of correlated electron systems at their interfaces and surfaces underpins the burgeoning field of "designer" quantum materials. Here, we show how an electronic reconstruction driven by surface polarity mediates a Stoner-like magnetic instability to itinerant ferromagne...
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.1811873115
更新日期:2018-12-18 00:00:00
abstract::Glycan-protein interactions are emerging as important modulators of membrane protein organization and dynamics, regulating multiple cellular functions. In particular, it has been postulated that glycan-mediated interactions regulate surface residence time of glycoproteins and endocytosis. How this precisely occurs 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.1402041111
更新日期:2014-07-29 00:00:00
abstract::In vitro T-cell receptor-induced programmed cell death in both activated T cells from human immunodeficiency virus-seronegative (HIV-) donors and resting T cells from HIV+ donors was substantially influenced by cytokines. Addition of exogenous recombinant "type 1" lymphokines interferon gamma and interleukin 2 (IL-2),...
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.91.25.11811
更新日期:1994-12-06 00:00:00
abstract::Systemic lupus erythematosus (SLE) is a multigenic autoimmune disease, and the major histocompatibility complex (MHC) class II polymorphism serves as a key genetic element. In SLE-prone (NZB x NZW)F(1) mice, the MHC H-2(d/z) heterozygosity (H-2(d) of NZB and H-2(z) of NZW) has a strong impact on disease; thus, congeni...
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.0405807101
更新日期:2004-09-21 00:00:00
abstract::An acid extract of pedal ganglia of the mollusc Mytilus edulis was fractionated by high-pressure liquid chromatography with a reverse-phase column. Peak fractions with retention times of those of [Met]- and [Leu]enkephalin were subjected to binding assays in both invertebrate and vertebrate tissues. The results showed...
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.81.3.955
更新日期:1984-02-01 00:00:00