Abstract:
:Knowing how motile bacteria move near and along a solid surface is crucial to understanding such diverse phenomena as the migration of infectious bacteria along a catheter, biofilm growth, and the movement of bacteria through the pore spaces of saturated soil, a critical step in the in situ bioremediation of contaminated aquifers. In this study, a tracking microscope is used to record the three-dimensional motion of Escherichia coli near a planar glass surface. Data from the tracking microscope are analyzed to quantify the effects of bacteria-surface interactions on the swimming behavior of bacteria. The speed of cells approaching the surface is found to decrease in agreement with the mathematical model of Ramia et al. [Ramia, M., Tullock, D. L. & Phan-Tien, N. (1993) Biophys J. 65,755-778], which represents the bacteria as spheres with a single polar flagellum rotating at a constant rate. The tendency of cells to swim adjacent to the surface is shown in computer-generated reproductions of cell traces. The attractive interaction potential between the cells and the solid surface is offered as one of several possible explanations for this tendency.
journal_name
Proc Natl Acad Sci U S Aauthors
Frymier PD,Ford RM,Berg HC,Cummings PTdoi
10.1073/pnas.92.13.6195subject
Has Abstractpub_date
1995-06-20 00:00:00pages
6195-9issue
13eissn
0027-8424issn
1091-6490journal_volume
92pub_type
杂志文章abstract::Given the slow unfolding of what may become catastrophic changes to Earth's climate, many are understandably distraught by failures of public policy to rise to the magnitude of the challenge. Few in the science community would think to question the scientific response to the unfolding changes. However, is the science ...
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.1906691116
更新日期:2019-12-03 00:00:00
abstract::A simple model for necking and detachment of subducting slabs is developed to include the coupling between grain-sensitive rheology and grain-size evolution with damage. Necking is triggered by thickened buoyant crust entrained into a subduction zone, in which case grain damage accelerates necking and allows for relat...
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.1415473112
更新日期:2015-02-03 00:00:00
abstract::IL-17 has been implicated in a number of inflammatory diseases, but the conditions of antigen exposure that drive the generation of Th17 responses have not been well defined. Epicutaneous (EC) immunization of mice with ovalbumin (OVA), which causes allergic skin inflammation with many characteristics of the skin lesio...
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.0706942104
更新日期:2007-10-02 00:00:00
abstract::Activins and inhibins, members of the type beta transforming growth factor superfamily of growth regulatory proteins, are produced in multiple tissues and affect diverse physiologic processes. Using embryonic stem cell technology, we previously demonstrated that inhibin can function as a gonadal tumor suppressor. In 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.91.19.8817
更新日期:1994-09-13 00:00:00
abstract::Neuroinflammation is an important contributor to neuronal pathology and death in neurodegenerative diseases and neuronal injury. Therapeutic interventions blocking the activity of the inflammatory kinase IKKβ, a key regulator of neuroinflammatory pathways, is protective in several animal models of neurodegenerative di...
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.1814246116
更新日期:2019-05-28 00:00:00
abstract::X-linked dystonia-parkinsonism (XDP) is a neurodegenerative disease associated with an antisense insertion of a SINE-VNTR-Alu (SVA)-type retrotransposon within an intron of TAF1 This unique insertion coincides with six additional noncoding sequence changes in TAF1, the gene that encodes TATA-binding protein-associated...
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.1712526114
更新日期:2017-12-19 00:00:00
abstract::Multiple independent mutations in neuroligin genes were identified in patients with familial autism, including the R451C substitution in neuroligin-3 (NL3). Previous studies showed that NL3(R451C) knock-in mice exhibited modestly impaired social behaviors, enhanced water maze learning abilities, and increased synaptic...
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.1111093108
更新日期:2011-08-16 00:00:00
abstract::Enveloped viruses enter cells via a process of membrane fusion between the viral envelope and a cellular membrane. For influenza virus, mutational data have shown that the membrane-inserted portions of the hemagglutinin protein play a critical role in achieving fusion. In contrast to the relatively well-understood ect...
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.1914188117
更新日期:2020-03-31 00:00:00
abstract::Seed dormancy is a trait of considerable adaptive significance because it maximizes seedling survival by preventing premature germination under unfavorable conditions. Understanding how seeds break dormancy and initiate growth is also of great agricultural and biotechnological interest. Abscisic acid (ABA) plays prima...
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.081594298
更新日期:2001-04-10 00:00:00
abstract::Plasmid pT181 is a 4437-base-pair, multicopy plasmid of Staphylococcus aureus that encodes tetracycline resistance. The replication of the leading strand of pT181 DNA initiates by covalent extension of a site-specific nick generated by the initiator protein at the origin of replication and proceeds by an asymmetric ro...
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.89.1.290
更新日期:1992-01-01 00:00:00
abstract::The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level ...
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
doi:10.1073/pnas.1512864112
更新日期:2015-12-22 00:00:00
abstract::The mahogany (mg) locus originally was identified as a recessive suppressor of agouti, a locus encoding a skin peptide that modifies coat color by antagonizing the melanocyte-stimulating hormone receptor or MC1-R. Certain dominant alleles of agouti cause an obesity syndrome when ectopic expression of the peptide aberr...
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.95.21.12707
更新日期:1998-10-13 00:00:00
abstract::Amoebae of the cellular slime mold Dictyostelium discoideum possess an extensive and dynamic endomembrane system that includes many types of acidic vacuoles. A light membrane fraction from Dictyostelium, rich in vacuolar-type H(+)-ATPase, has been described [Padh, H., Lavasa, M. & Steck, T.L. (1989) J. Cell Biol. 108,...
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.89.17.8025
更新日期:1992-09-01 00:00:00
abstract::Agrobacterium tumefaciens causes crown gall tumors on various plants by delivering transferred DNA (T-DNA) and virulence proteins into host plant cells. Under laboratory conditions, the bacterium is widely used as a vector to genetically modify a wide range of organisms, including plants, yeasts, fungi, and algae. Var...
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.1612098114
更新日期:2017-03-14 00:00:00
abstract::HUMAN LIVER ALCOHOL DEHYDROGENASE (ALCOHOL: NAD(+) oxidoreductase, EC 1.1.1.1), homogeneous by physicochemical criteria, has been available in quantity only recently [Lange, L. G. & Vallee, B. L. (1976) Biochemistry 15, 4681-4686]. Until now, the biochemical basis of human alcohol metabolism had to be extrapolated fro...
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.74.10.4378
更新日期:1977-10-01 00:00:00
abstract::Tumor growth requires neoangiogenesis. VEGF is the most potent proangiogenic factor. Dysregulation of hypoxia-inducible factor (HIF) or cytokine stimuli such as those involving the chemokine receptor 4/stromal-derived cell factor 1 (CXCR4/SDF-1) axis are the major cause of ectopic overexpression of VEGF in tumors. Alt...
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.1008256107
更新日期:2010-08-10 00:00:00
abstract::An Epstein-Barr virus (EBV) deletion mutant, HR-1, cannot immortalize lymphocytes. HR-1 was derived from a virus strain, Jijoye, that is immortalization competent. Using human antiserum from certain patients with chronic active EBV infection, we have identified in Jijoye cells a protein of apparent mass of 78-80 kDa 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.82.21.7429
更新日期:1985-11-01 00:00:00
abstract::Citrullinemia is an inborn error of metabolism due to deficiency of the urea cycle enzyme, argininosuccinate synthetase [L-citrulline:L-aspartate ligase (AMP-forming), EC 6.3.4.5]. The disease was first described in humans but was recently reported in dairy cattle in Australia. Here we report the nucleotide sequence 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.86.20.7947
更新日期:1989-10-01 00:00:00
abstract::Kinesin-73 cDNA was shown to encode a kinesin heavy chain protein that contains an N-terminal motor domain and a long central region that lacks extensive coiled-coils. The amino acid sequence of the motor domain of kinesin-73 protein is most closely related to the motor domains of Caenorhabditis elegans unc-104 and mo...
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.94.4.1086
更新日期:1997-02-18 00:00:00
abstract::Many models of morphogenesis are forced to assume specific mechanical properties of cells, because the actual mechanical properties of living tissues are largely unknown. Here, we measure the rheology of epithelial cells in the cellularizing Drosophila embryo by injecting magnetic particles and studying their 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.1616659114
更新日期:2017-01-31 00:00:00
abstract::Transgenic mice expressing the Pim-1 kinase are predisposed to develop T-cell lymphomas with a long latency period of about 7-9 months. However, the exact functional basis of the oncogenic activity of Pim-1 remains obscure. C57BL/6 mice homozygous for the lpr mutation develop a well-described lymphoproliferative syndr...
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.90.22.10734
更新日期:1993-11-15 00:00:00
abstract::Conflicts of interest between the community and its members are at the core of human social dilemmas. If observed selfishness has future costs, individuals may hide selfish acts but display altruistic ones, and peers aim at identifying the most selfish persons to avoid them as future social partners. An interaction 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.1108996108
更新日期:2011-11-08 00:00:00
abstract::Plants, as sessile organisms, must coordinate various physiological processes to adapt to ever-changing surrounding environments. Stomata, the epidermal pores facilitating gas and water exchange, play important roles in optimizing photosynthetic efficiency and adaptability. Stomatal development is under the control of...
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.1400542111
更新日期:2014-07-22 00:00:00
abstract::Interferon γ-inducible protein 16 (IFI16) and cGMP-AMP synthase (cGAS) have both been proposed to detect herpesviral DNA directly in herpes simplex virus (HSV)-infected cells and initiate interferon regulatory factor-3 signaling, but it has been unclear how two DNA sensors could both be required for this response. We ...
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.1424637112
更新日期:2015-04-07 00:00:00
abstract::Chlorarachniophytes are amoeboid algae with unusual chloroplasts. Instead of the usual two membranes that surround the chloroplasts of plants, green algae, and red algae, the chloroplasts of chlorarachniophytes have four bounding membranes. The extra membranes may reflect an unusual origin of chlorarachniophyte chloro...
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.91.9.3690
更新日期:1994-04-26 00:00:00
abstract::Locomotion of the nematode Caenorhabditis elegans is a key observable used in investigations ranging from behavior to neuroscience to aging. However, while the natural environment of this model organism is 3D, quantitative investigations of its locomotion have been mostly limited to 2D motion. Here, we present a 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.1706754115
更新日期:2018-04-17 00:00:00
abstract::It has been shown previously that the binding of oxidized low-density lipoprotein (OxLDL) to resident mouse peritoneal macrophages can be inhibited (up to 70%) by the apoprotein B (apoB) isolated from OxLDL, suggesting that macrophage recognition of OxLDL is primarily dependent on its modified protein moiety. However,...
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.96.11.6347
更新日期:1999-05-25 00:00:00
abstract::Transcription initiation is a dynamic process in which RNA polymerase (RNAP) and promoter DNA act as partners, changing in response to one another, to produce a polymerase/promoter open complex (RPo) competent for transcription. In Escherichia coli RNAP, region 1.1, the N-terminal 100 residues of sigma(70), is thought...
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.0808133106
更新日期:2009-01-20 00:00:00
abstract::Rad51 is a core component of the eukaryotic homologous recombination machinery and is responsible for key mechanistic steps during strand invasion. Higher order oligomers of Rad51 display a remarkable degree of structural variation, forming rings, compressed filaments, and elongated filaments. It is unclear whether Ra...
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.0811465106
更新日期:2009-08-04 00:00:00
abstract::Based on the analysis of genomic DNA from single healthy animals of each of five primate species, nucleotide and predicted amino acid sequences of the infectious amyloid precursor gene of higher apes (Gorilla and Pan) and Old World (Macaca) and New World (Ateles, Saimiri) monkeys showed 95-99% homology to the human se...
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.91.25.12159
更新日期:1994-12-06 00:00:00