Abstract:
:Evolutionary innovations often arise from complex genetic and ecological interactions, which can make it challenging to understand retrospectively how a novel trait arose. In a long-term experiment, Escherichia coli gained the ability to use abundant citrate (Cit(+)) in the growth medium after ∼31,500 generations of evolution. Exploiting this previously untapped resource was highly beneficial: later Cit(+) variants achieve a much higher population density in this environment. All Cit(+) individuals share a mutation that activates aerobic expression of the citT citrate transporter, but this mutation confers only an extremely weak Cit(+) phenotype on its own. To determine which of the other >70 mutations in early Cit(+) clones were needed to take full advantage of citrate, we developed a recursive genomewide recombination and sequencing method (REGRES) and performed genetic backcrosses to purge mutations not required for Cit(+) from an evolved strain. We discovered a mutation that increased expression of the dctA C4-dicarboxylate transporter greatly enhanced the Cit(+) phenotype after it evolved. Surprisingly, strains containing just the citT and dctA mutations fully use citrate, indicating that earlier mutations thought to have potentiated the initial evolution of Cit(+) are not required for expression of the refined version of this trait. Instead, this metabolic innovation may be contingent on a genetic background, and possibly ecological context, that enabled citT mutants to persist among competitors long enough to obtain dctA or equivalent mutations that conferred an overwhelming advantage. More generally, refinement of an emergent trait from a rudimentary form may be crucial to its evolutionary success.
journal_name
Proc Natl Acad Sci U S Aauthors
Quandt EM,Deatherage DE,Ellington AD,Georgiou G,Barrick JEdoi
10.1073/pnas.1314561111subject
Has Abstractpub_date
2014-02-11 00:00:00pages
2217-22issue
6eissn
0027-8424issn
1091-6490pii
1314561111journal_volume
111pub_type
杂志文章abstract::Candidate single-nucleotide polymorphisms (SNPs) were analyzed for associations to an unselected whole genome pool of tumor mRNA transcripts in 50 unrelated patients with breast cancer. SNPs were selected from 203 candidate genes of the reactive oxygen species pathway. We describe a general statistical framework for 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.0601893103
更新日期:2006-05-16 00:00:00
abstract::The transcription and processing of mitochondrial 21S rRNA in a petite strain of Saccharomyces cerevisiae has been examined by electron microscopic analysis of R-loop hybrids and by hybridization of labeled mitochondrial DNA probes to RNA transferred to diazobenzyloxymethyl paper. We have shown the presence of a large...
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.77.3.1417
更新日期:1980-03-01 00:00:00
abstract::The biosynthesis and endocrine regulation of sex pheromone production in the female German cockroach (Blattella germanica) were determined. Radio-TLC and radio-GLC were used to demonstrate the metabolism of 3,11-dimethylnonacosane, a major cuticular lipid component, to the corresponding alkan-2-ol and methyl ketone. [...
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.89.13.6050
更新日期:1992-07-01 00:00:00
abstract::Gaseous molecular ions containing argon and perchlorethylene, Ar(n)(C(2)Cl(4))(m) (+) in which n >/= 1-29 and m >/= 1-4, are produced by electron bombardment of van der Waals clusters formed by expanding an Ar/C(2)Cl(4) mixture through a supersonic nozzle. Previous attempts to observe such ions in a high-pressure mass...
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.78.12.7250
更新日期:1981-12-01 00:00:00
abstract::Incubation of physiological concentrations of 125I-labeled insulin with liver membranes in the presence of anti-insulin IgG results in a 7- to 15-fold increase in the specific binding of the hormone. The low-affinity/high-capacity binding sites are replaced by an apparently homogeneous class of high-affinity sites, an...
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.76.6.2720
更新日期:1979-06-01 00:00:00
abstract::Management of the diverse fisheries of the world has had mixed success. While managing single species in data-rich environments has been largely effective, perhaps the greatest challenge facing fishery managers is how to deal with mixed stocks of fish with a range of life histories that reside in the same location. Be...
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.1705169114
更新日期:2017-08-22 00:00:00
abstract::A survey was performed to estimate the frequency of enterohemorrhagic Escherichia coli O157:H7 or O157:nonmotile (EHEC O157) in feces and on hides within groups of fed cattle from single sources (lots) presented for slaughter at meat processing plants in the Midwestern United States, as well as frequency of carcass 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.060024897
更新日期:2000-03-28 00:00:00
abstract::In higher eukaryotic cells, mitochondria are essential subcellular organelles for energy production, cell signaling, and the biosynthesis of biomolecules. The mitochondrial DNA (mtDNA) genome is indispensable for mitochondrial function because it encodes protein subunits of the electron transport chain and a full set ...
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.1911252116
更新日期:2019-09-03 00:00:00
abstract::We report on a fundamental technological advance for multilayer polydimethylsiloxane (PDMS) microfluidics. Vertical passages (vias), connecting channels located in different layers, are fabricated monolithically, in parallel, by simple and easy means. The resulting 3D connectivity greatly expands the potential complex...
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.0602890103
更新日期:2006-08-15 00:00:00
abstract::Microsomal NADPH-cytochrome P450 reductase (CPR) is one of only two mammalian enzymes known to contain both FAD and FMN, the other being nitric-oxide synthase. CPR is a membrane-bound protein and catalyzes electron transfer from NADPH to all known microsomal cytochromes P450. The structure of rat liver CPR, expressed ...
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.94.16.8411
更新日期:1997-08-05 00:00:00
abstract::The proteasome is responsible for degradation of substrates of the ubiquitin pathway. 20S proteasomes are cylindrical particles with subunits arranged in a stack of four heptameric rings. The outer rings are composed of alpha subunits, and the inner rings are composed of beta subunits. A well-characterized archaeal pr...
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.94.14.7156
更新日期:1997-07-08 00:00:00
abstract::Mucolipidosis III (ML III), or pseudo-Hurler polydystrophy, is an inherited childhood disorder characterized biochemically by low activities and abnormal electrophoretic patterns of multiple lysosomal enzymes in fibroblasts. The primary deficiency of ML III has been proposed to be in UDP-N-acetylglucosamine:lysosomal ...
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.79.23.7420
更新日期:1982-12-01 00:00:00
abstract::The translational apparatus in cell-free extracts prepared from L cells infected with reovirus undergoes a time-dependent transition from cap dependence to cap independence. Extracts from uninfected L cells translate capped reovirus mRNA at high efficiency and synthesize the expected three size classes of reovirus pol...
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.77.1.152
更新日期:1980-01-01 00:00:00
abstract::A culture of mouse A9 cells yielded clones of both high and low malignancy. Confirmation of the differences in malignancy of the clones was obtained after their hybridization with subclones of YACIR a lymphoma induced by Moloney leukemia virus. Low malignant A9 clones suppressed the malignancy of the YACIR partner 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.73.6.2004
更新日期:1976-06-01 00:00:00
abstract::FUS3 is functionally redundant with KSS1, a homologous yeast protein kinase, for a step(s) in signal transduction between the beta subunit of the guanine nucleotide binding protein (G protein), STE4, and the mating type-specific transcriptional activator, STE12. Either FUS3 or KSS1 can execute this function; when neit...
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.88.21.9392
更新日期:1991-11-01 00:00:00
abstract::The effect of combining hormonal treatment consisting of long-acting microcapsules of the agonist [D-Trp6]LH-RH (the D-tryptophan-6 analog of luteinizing hormone-releasing hormone) with the chemotherapeutic agent cyclophosphamide was investigated in the Dunning R-3327H rat prostate cancer model. Microcapsules of [D-Tr...
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.82.8.2498
更新日期:1985-04-01 00:00:00
abstract::The synthesis of graphene materials is typically carried out by oxidizing graphite to graphite oxide followed by a reduction process. Numerous methods exist for both the oxidation and reduction steps, which causes unpredictable contamination from metallic impurities into the final material. These impurities are known ...
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.1413389111
更新日期:2014-09-23 00:00:00
abstract::The evolution of human languages is driven both by primitive biases present in the human sensorimotor systems and by cultural transmission among speakers. However, whether the design of the language faculty is further shaped by linguistic biological biases remains controversial. To address this question, we used near-...
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.1318261111
更新日期:2014-04-22 00:00:00
abstract::B-G antigens are cell-surface molecules encoded by a highly polymorphic multigene family located in the chicken major histocompatibility complex (MHC). Rabbit antisera to B-G molecules immunoprecipitate 3-6 bands from iodinated erythrocytes by sodium dodecyl sulfate (SDS) gels under reducing conditions. These are all ...
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.87.21.8277
更新日期:1990-11-01 00:00:00
abstract::In an 1885 paper, E. Picard defined a subgroup Tau(Lambda) of PU(2,1) generated by monodromies and depending on parameters Lambda = (lambda(1),lambda(2),lambda(3),lambda(4)), 0 < lambda(i) < 1, < lambda(i) < 3, lambda(i) + lambda(j) >/= 1, 1 = i < j = 4. The family Tau(Lambda) resembles the family of groups Tau([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.78.10.5948
更新日期:1981-10-01 00:00:00
abstract::Chlorpromazine (3 x 10(-4)M) prevents the stimulation of adenyl cyclase activity in thyroid membranes produced by thyrotropin and prostaglandin, ACTH stimulation of adenyl cyclase in adrenal tissue, and glucagon- and epinephrine-stimulation of adenyl cyclase activity in liver. Baseline activity is unaffected. Parathyr...
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.65.2.454
更新日期:1970-02-01 00:00:00
abstract::Managing excess nutrients remains a major obstacle to improving ecosystem service benefits of urban waters. To inform more ecologically based landscape nutrient management, we compared watershed inputs, outputs, and retention for nitrogen (N) and phosphorus (P) in seven subwatersheds of the Mississippi River in St. 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.1618536114
更新日期:2017-04-18 00:00:00
abstract::Selection of mammalian cells in progressively increasing concentrations of methotrexate results in selective amplification of DNA sequences coding for dihydrofolate reductase (tetrahydrofolate dehydrogenase, 5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase, EC 1.5.1.3). In some cell variants the amplified genes are stabl...
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.76.11.5669
更新日期:1979-11-01 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::DNA heteroduplexes with single unpaired bases of the four different kinds were prepared by annealing separated strands of bacteriophage lambda DNA and used to transfect Escherichia coli. Genetic analysis of the progeny phages obtained from transfected bacteria indicates that the E. coli mismatch repair system can reco...
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.83.10.3395
更新日期:1986-05-01 00:00:00
abstract::The intermediates and the rate-limiting step in the crystallization of deoxygenated sickle hemoglobin have been determined by a kinetic study with the use of electron microscopy. In slowly stirred solutions of deoxygenated hemoglobin S [Pumphrey, J. & Steinhardt, J. (1977) J. Mol. Biol. 112, 359--375], the sequential ...
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.77.2.944
更新日期:1980-02-01 00:00:00
abstract::The structure of the adeno-associated virus (AAV-2) has been determined to 3-A resolution by x-ray crystallography. AAV is being developed as a vector for gene therapy to treat diseases including hemophilia, cancer, and cystic fibrosis. As in the distantly related autonomous parvoviruses, the capsid protein has a beta...
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.162250899
更新日期:2002-08-06 00:00:00
abstract::Dendritic cells (DCs) and B cells present antigen-derived peptides bound to MHC class II (MHC II) molecules for recognition by CD4-positive T lymphocytes. DCs control the intracellular traffic of peptide-MHC II complexes by regulating the ubiquitination of MHC II. In resting or "immature" DCs, ubiquitinated MHC II mol...
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.1202977109
更新日期:2012-06-05 00:00:00
abstract::The acid-sensing ion channel-1 (ASIC1) contributes to synaptic plasticity and may influence the response to cerebral ischemia and acidosis. We found that cAMP-dependent protein kinase phosphorylated heterologously expressed ASIC1 and endogenous ASIC1 in brain slices. ASIC1 also showed significant phosphorylation under...
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.252782799
更新日期:2003-02-18 00:00:00
abstract::In the United States, the iconic groundfish fishery for Gulf of Maine cod has endured several dramatic reductions in annual catch limits and been federally declared an economic disaster. Using a repeated cross-sectional survey of fishing captains to assess potential social impacts of the fishery failure, we found that...
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.1913914116
更新日期:2019-11-12 00:00:00