Abstract:
:A long (20-30 micrometer), wide (3-5 micrometer) microbial-mat bacterium from the Ebro Delta (Tarragona, Spain) was grown in mixed culture and videographed live. Intracellular elemental sulfur globules and unique cell termini were observed in scanning-electron-microprobe and transmission-electron micrographs. A polar organelle underlies bundles of greater than 60 flagella at each indented terminus. These Gram-negative bacteria bend, flex, and swim in a spiral fashion; they translate at speeds greater than 10 body lengths per second. The large size of the spirillum permits direct observation of cell motility in single individual bacteria. After desiccation (i.e., absence of standing water for at least 24 h), large populations developed in mat samples remoistened with sea water. Ultrastructural observations reveal abundant large sulfur globules irregularly distributed in the cytoplasm. A multilayered cell wall, pliable and elastic yet rigid, distends around the sulfur globules. Details of the wall, multiflagellated termini, and large cytoplasmic sulfur globules indicate that these fast-moving spirilla are distinctive enough to warrant a genus and species designation: Titanospirillum velox genus nov., sp. nov. The same collection techniques at a similar habitat in the United States (Plum Island, northeast Essex County, Massachusetts) also yielded large populations of the bacterium among purple phototrophic and other inhabitants of sulfurous microbial-mat muds. The months-long survival of T. velox from Spain and from the United States in closed jars filled with mud taken from both localities leads us to infer that this large spirillum has a cosmopolitan distribution.
journal_name
Proc Natl Acad Sci U S Aauthors
Guerrero R,Haselton A,Solé M,Wier A,Margulis Ldoi
10.1073/pnas.96.20.11584keywords:
subject
Has Abstractpub_date
1999-09-28 00:00:00pages
11584-8issue
20eissn
0027-8424issn
1091-6490journal_volume
96pub_type
杂志文章abstract::Genomic clones of the human non-N-methyl-D-aspartate (non-NMDA) glutamate receptor subunit GluR5 were isolated by high-stringency screening of a cosmid library using the rat cDNA as a probe. The chromosomal localization of the human GluR5 gene has been established. Southern hybridization of DNA isolated from mapping 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.90.1.178
更新日期:1993-01-01 00:00:00
abstract::Two genes have a synthetically lethal relationship when the silencing or inhibiting of 1 gene is only lethal in the context of a mutation or activation of the second gene. This situation offers an attractive therapeutic strategy, as inhibition of such a gene will only trigger cell death in tumor cells with an activate...
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.0901418106
更新日期:2009-08-04 00:00:00
abstract::The adult brain exhibits a local increase in cortical blood flow in response to external stimulus. However, broadly varying hemodynamic responses in the brains of newborn and young infants have been reported. Particular controversy exists over whether the "true" neonatal response to stimulation consists of a decrease ...
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.1212785110
更新日期:2013-03-12 00:00:00
abstract::Fast axoplasmic transport was studied in dorsal root ganglion cells of the cat. Proteins carried in the fast axoplasmic flow were labeled after an intraganglionic injection of (L)-[4,5-(3)H]leucine. The rate of transport was 380 +/- 26 mm/day in both the central and peripheral branches of the bifurcating axons that ar...
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.70.5.1521
更新日期:1973-05-01 00:00:00
abstract::Productive T cell recognition of antigen-presenting cells (APCs) is normally accompanied by the formation of a cell-cell contact called the "immunological synapse." Our understanding of the steps leading up to this formation has been limited by the absence of tools for analyzing 3D surfaces and surface distributions 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.192573999
更新日期:2002-11-12 00:00:00
abstract::Mutations in fibroblast growth factor receptor 2 (FGFR2) and its ligand, FGF10, are known to cause lacrimo-auriculo-dento-digital (LADD) syndrome. Multiple gain-of-function mutations in FGF receptors have been implicated in a variety of severe skeletal disorders and in many cancers. We aimed to elucidate the mechanism...
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.0709905104
更新日期:2007-12-11 00:00:00
abstract::To facilitate analysis of plant cell wall polysaccharide structure and composition, we cloned 74 genes encoding polysaccharide-degrading enzymes from Aspergillus nidulans, Aspergillus fumigatus, and Neurospora crassa and expressed the genes as secreted proteins with C-terminal Myc and 6x His tags. Most of the recombin...
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.0604632103
更新日期:2006-07-25 00:00:00
abstract::Organic hydroperoxide resistance (Ohr) enzymes are unique Cys-based, lipoyl-dependent peroxidases. Here, we investigated the involvement of Ohr in bacterial responses toward distinct hydroperoxides. In silico results indicated that fatty acid (but not cholesterol) hydroperoxides docked well into the active site of Ohr...
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.1619659114
更新日期:2017-01-10 00:00:00
abstract::Programmed cell death (PCD) of mammary alveolar cells during involution commences within hours of the end of suckling. Locally, milk accumulates within alveolar lumens; systemically, levels of lactogenic hormones fall. Four experimental models were used to define the role of local factors as compared with systemic hor...
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.94.7.3425
更新日期:1997-04-01 00:00:00
abstract::A specific high-affinity receptor for leukotriene C4 (LTC4) has been identified on segments of longitudinal smooth muscle from guinea pig ileum, in disrupted cells obtained from the ileal segments, and in subcellular fractions enriched for mitochondrial membranes and plasma membranes, respectively. Specific [3H]LTC4 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.81.14.4529
更新日期:1984-07-01 00:00:00
abstract::Seasonal changes of daylength (photoperiod) affect the expression of hormonal and behavioral circadian rhythms in a variety of organisms. In mammals, such effects might reflect photoperiodic changes in the circadian pace-making system [located in the suprachiasmatic nucleus (SCN) of the hypothalamus] that governs thes...
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.92.17.7754
更新日期:1995-08-15 00:00:00
abstract::Shigella sonnei is a human-adapted pathogen that is emerging globally as the dominant agent of bacterial dysentery. To investigate local establishment, we sequenced the genomes of 263 Vietnamese S. sonnei isolated over 15 y. Our data show that S. sonnei was introduced into Vietnam in the 1980s and has undergone locali...
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.1308632110
更新日期:2013-10-22 00:00:00
abstract::For over 40 y the dominant theory of stomatal behavior has been that plants should open stomates until the carbon gained by an infinitesimal additional opening balances the additional water lost times a water price that is constant at least over short periods. This theory has persisted because of its remarkable succes...
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.1615144113
更新日期:2016-11-15 00:00:00
abstract::In this report we analyzed genetically informative data to investigate within-person change and between-person differences in late-life cognitive abilities as a function of childhood social class. We used data from nine testing occasions spanning 28 y in the Swedish Adoption/Twin Study of Aging and parental social cla...
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.1620603114
更新日期:2017-07-03 00:00:00
abstract::In the nitrogen-fixing symbiosis between legume hosts and rhizobia, the bacteria are engulfed by a plant cell membrane to become intracellular organelles. In the model legume Medicago truncatula, internalization and differentiation of Sinorhizobium (also known as Ensifer) meliloti is a prerequisite for nitrogen fixati...
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.1500123112
更新日期:2015-12-08 00:00:00
abstract::Trimeric class I virus fusion proteins undergo a series of conformational rearrangements that leads to the association of C- and N-terminal heptad repeat domains in a "trimer-of-hairpins" structure, facilitating the apposition of viral and cellular membranes during fusion. This final fusion hairpin structure is sustai...
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.0406696101
更新日期:2004-10-19 00:00:00
abstract::Mammalian DAI (DNA-dependent activator of IFN-regulatory factors), an activator of the innate immune response, senses cytosolic DNA by using 2 N-terminal Z-DNA binding domains (ZBDs) and a third putative DNA binding domain located next to the second ZBD. Compared with other previously known ZBDs, the second ZBD of hum...
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.0810463106
更新日期:2008-12-30 00:00:00
abstract::Circumnutation and winding in plants are universal growth movements that allow plants to survive despite their sessile nature. However, the detailed molecular mechanisms controlling these phenomena remain unclear. We previously found that a gravitropic mutant of Japanese morning glory (Pharbitis nil or Ipomoea nil), S...
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.0504617102
更新日期:2005-12-20 00:00:00
abstract::Type I cadherin cell-adhesion proteins are similar in sequence and structure and yet are different enough to mediate highly specific cell-cell recognition phenomena. It has previously been shown that small differences in the homophilic and heterophilic binding affinities of different type I family members can account ...
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.1416737111
更新日期:2014-10-07 00:00:00
abstract::Sprouty proteins act as intracellular inhibitors of receptor tyrosine kinase signaling. Here we show that the mammalian Sprouty2 protein contains an iron-sulfur complex that can exist in an oxidized, reduced, or nitrosylated state. Purified Sprouty2 assembles into large monodisperse spheres containing approximately 24...
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.0506714102
更新日期:2005-09-27 00:00:00
abstract::Neuromelanin (NM) isolated from the substantia nigra region of the human brain was studied by scanning probe and photoelectron emission microscopies. Atomic force microscopy reveals that NM granules are comprised of spherical structures with a diameter of approximately 30 nm, similar to that observed for Sepia cuttlef...
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.0604010103
更新日期:2006-10-03 00:00:00
abstract::Amyotrophic lateral sclerosis is a neurodegenerative syndrome associated with 114 mutations in the gene encoding the cytosolic homodimeric enzyme Cu/Zn superoxide dismutase (SOD). In this article, we report that amyotrophic lateral sclerosis-associated SOD mutations with distinctly different disease progression can 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.0501957102
更新日期:2005-07-12 00:00:00
abstract::In order to define the protease domain of human immunodeficiency virus 1, various regions of the pol open reading frame were cloned and expressed in Escherichia coli. Antiserum directed against the conserved retroviral protease active site was used to identify pol precursor and processed species containing the presume...
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.85.8.2449
更新日期:1988-04-01 00:00:00
abstract::Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease of motor neurons. The inherited form of the disease, familial ALS, represents 5-10% of the total cases, and the best documented of these are due to lesions in SOD1, the gene encoding copper-zinc superoxide dismutase (CuZnSOD). The mechanism by w...
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.0730423100
更新日期:2003-04-01 00:00:00
abstract::Cytochrome P450 monooxygenases (P450) in the honey bee, Apis mellifera, detoxify phytochemicals in honey and pollen. The flavonol quercetin is found ubiquitously and abundantly in pollen and frequently at lower concentrations in honey. Worker jelly consumed during the first 3 d of larval development typically contains...
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.1614864114
更新日期:2017-03-07 00:00:00
abstract::The BTB domain (also known as the POZ domain) is an evolutionarily conserved protein-protein interaction motif found at the N terminus of 5-10% of C2H2-type zinc-finger transcription factors, as well as in some actin-associated proteins bearing the kelch motif. Many BTB proteins are transcriptional regulators that med...
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.95.21.12123
更新日期:1998-10-13 00:00:00
abstract::Reduced intake of nutrients [calorie restriction (CR)] extends longevity in organisms ranging from yeast to mammals. Mutations affecting somatotropic, insulin, or homologous signaling pathways can increase life span in worms, flies, and mice, and there is considerable evidence that reduced secretion of insulin-like gr...
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.0600161103
更新日期:2006-05-16 00:00:00
abstract::An automatic protein design procedure is used to select amino acid sequences that optimize the folding free energy function for a given protein. The only information used in designing the sequences is a set of known backbone structures for each protein, a rotamer library, and a well established classical empirical for...
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.212068599
更新日期:2002-10-15 00:00:00
abstract::Radiation dose rates were evaluated in three areas neighboring a restricted area within a 20- to 50-km radius of the Fukushima Daiichi Nuclear Power Plant in August-September 2012 and projected to 2022 and 2062. Study participants wore personal dosimeters measuring external dose equivalents, almost entirely from depos...
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.1315684111
更新日期:2014-03-11 00:00:00
abstract::We have compared chicken erythrocyte linker histones H1 and H5 binding to a synthetic four-way DNA junction. Each histone binds to form a single complex, with an affinity which permits competition against a large excess of linear duplex DNA. The affinity of H5 is higher than that of H1. The globular domain from either...
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.91.9.3525
更新日期:1994-04-26 00:00:00