Proceedings of the Natural Academy of Sciences

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  • Flagella-independent motility in Salmonella [Microbiology]
    [Feb 2015]

    Flagella are multiprotein complexes necessary for swimming and swarming motility. In Salmonella enterica serovar Typhimurium, flagella-mediated motility is repressed by the PhoP/PhoQ regulatory system. We now report that Salmonella can move on 0.3% agarose media in a flagella-independent manner when experiencing the PhoP/PhoQ-inducing signal low Mg2+. This motility requires the...
    Categories: Journal Articles
  • Diverse viral miRNAs inhibit interferon signaling [Microbiology]
    [Feb 2015]

    Diverse viruses encode regulatory RNAs called microRNAs (miRNAs). Despite much progress, the functions of the majority of viral miRNAs remain unknown. Most previous studies have used biochemical methods to uncover targets of viral miRNAs, but it is unclear what fraction of these targets is functionally important. Here, we apply an...
    Categories: Journal Articles
  • Peptide-governed cell differentiation in Nostoc [Microbiology]
    [Feb 2015]

    Nostoc punctiforme is a versatile cyanobacterium that can live either independently or in symbiosis with plants from distinct taxa. Chemical cues from plants and N. punctiforme were shown to stimulate or repress, respectively, the differentiation of infectious motile filaments known as hormogonia. We have used a polyketide synthase mutant that...
    Categories: Journal Articles
  • Sound representation in higher language areas [Neuroscience]
    [Feb 2015]

    How language is encoded by neural activity in the higher-level language areas of humans is still largely unknown. We investigated whether the electrophysiological activity of Broca’s area correlates with the sound of the utterances produced. During speech perception, the electric cortical activity of the auditory areas correlates with the sound...
    Categories: Journal Articles
  • PTP{sigma} as a coreceptor for glypicans [Neuroscience]
    [Feb 2015]

    Leukocyte common antigen-related receptor protein tyrosine phosphatases—comprising LAR, PTPδ, and PTPσ—are synaptic adhesion molecules that organize synapse development. Here, we identify glypican 4 (GPC-4) as a ligand for PTPσ. GPC-4 showed strong (nanomolar) affinity and heparan sulfate (HS)-dependent interaction with the Ig domains of PTPσ. PTPσ bound only to proteolytically...
    Categories: Journal Articles
  • BDNF enhances myocardial contractility/relaxation [Physiology]
    [Feb 2015]

    BDNF and its associated tropomyosin-related kinase receptor B (TrkB) nurture vessels and nerves serving the heart. However, the direct effect of BDNF/TrkB signaling on the myocardium is poorly understood. Here we report that cardiac-specific TrkB knockout mice (TrkB−/−) display impaired cardiac contraction and relaxation, showing that BDNF/TrkB signaling acts constitutively...
    Categories: Journal Articles
  • FREE1 regulates protein trafficking and autophagy [Plant Biology]
    [Feb 2015]

    Protein turnover can be achieved via the lysosome/vacuole and the autophagic degradation pathways. Evidence has accumulated revealing that efficient autophagic degradation requires functional endosomal sorting complex required for transport (ESCRT) machinery. However, the interplay between the ESCRT machinery and the autophagy regulator remains unclear. Here, we show that FYVE domain...
    Categories: Journal Articles
  • Context-dependent categorical perception [Psychological and Cognitive Sciences]
    [Feb 2015]

    Some of the psychological abilities that underlie human speech are shared with other species. One hallmark of speech is that linguistic context affects both how speech sounds are categorized into phonemes, and how different versions of phonemes are produced. We here confirm earlier findings that swamp sparrows categorically perceive the...
    Categories: Journal Articles
  • Chemodetection in fluctuating environments [Systems Biology]
    [Feb 2015]

    Variability in the chemical composition of the extracellular environment can significantly degrade the ability of cells to detect rare cognate ligands. Using concepts from statistical detection theory, we formalize the generic problem of detection of small concentrations of ligands in a fluctuating background of biochemically similar ligands binding to the...
    Categories: Journal Articles
  • Correction for Li et al., Waking sleeping algal cells [Correction]
    [Feb 2015]

    COMMENTARY Correction for “Waking sleeping algal cells,” by Xiaobo Li, James G. Umen, and Martin C. Jonikas, which appeared in issue 44, November 4, 2014, of Proc Natl Acad Sci USA (111:15610–15611; first published October 23, 2014; 10.1073/pnas.1418295111). The authors note that on page 15610, center column, first full paragraph,...
    Categories: Journal Articles
  • Correction for Barcellos et al., Preparedness of Americans for the Affordable Care Act [Correction]
    [Feb 2015]

    ECONOMIC SCIENCES Correction for “Preparedness of Americans for the Affordable Care Act,” by Silvia Helena Barcellos, Amelie C. Wuppermann, Katherine Grace Carman, Sebastian Bauhoff, Daniel L. McFadden, Arie Kapteyn, Joachim K. Winter, and Dana Goldman, which appeared in issue 15, April 15, 2014, of Proc Natl Acad Sci USA (111:5497–5502;...
    Categories: Journal Articles
  • Correction for Han et al., Structural basis for the auxin-induced transcriptional regulation by Aux/IAA17 [Correction]
    [Feb 2015]

    BIOPHYSICS AND COMPUTATIONAL BIOLOGY Correction for “Structural basis for the auxin-induced transcriptional regulation by Aux/IAA17,” by Mookyoung Han, Yangshin Park, Iktae Kim, Eun-Hee Kim, Tae-Kyung Yu, Sangkee Rhee, and Jeong-Yong Suh, which appeared in issue 52, December 30, 2014, of Proc Natl Acad Sci USA (111:18613–18618; first published December 15,...
    Categories: Journal Articles
  • Correction for Li et al., Arabidopsis ribosomal proteins control vacuole trafficking and developmental programs through the regulation of lipid metabolism [Correction]
    [Feb 2015]

    PLANT BIOLOGY Correction for “Arabidopsis ribosomal proteins control vacuole trafficking and developmental programs through the regulation of lipid metabolism,” by Ruixi Li, Ruobai Sun, Glenn R. Hicks, and Natasha V. Raikhel, which appeared in issue 1, January 6, 2015, of Proc Natl Acad Sci USA (112:E89–E98; first published December 22,...
    Categories: Journal Articles
  • In This Issue [This Week in PNAS]
    [Feb 2015]

    Simplifying energy storage through reversible catalysis Hydrogenation and dehydrogenation reactions represent potentially efficient and affordable means to store and reclaim hydrogen as an energy carrier. However, at present, this approach remains impracticable because the known catalysts and conditions for the two reactions differ substantially. Peter Bonitatibus Jr. et al. (pp....
    Categories: Journal Articles
  • Herman N. Eisen: Mentor to many [Retrospectives]
    [Feb 2015]

    Herman Eisen passed away on November 2, 2014, at the age of 96. During his long and distinguished career, Herman was a mentor to those who trained in his laboratory (ourselves included), to those who collaborated with him over the years, and to many faculty and colleagues at Massachusetts Institute...
    Categories: Journal Articles
  • Profile of Brian Charlesworth [Profiles]
    [Feb 2015]

    National Academy of Sciences foreign associate Brian Charlesworth has been at the forefront of evolutionary genetics research for the last four decades. Using theoretical ideas to design experiments and experimental data as a stimulant for the development of theory, Charlesworth investigates fundamental life processes. His work has contributed to improved...
    Categories: Journal Articles
  • Altruism, self-interest, and energy consumption [Sustainability Science]
    [Feb 2015]

    How can we encourage greater energy efficiency? Estimates that take account of behavioral plasticity—the ease with which actions can be taken—indicate that the United States could reduce overall greenhouse gas emissions by 7% if households adopted simple and money-saving efficiency actions (1). However, most households are not taking these actions...
    Categories: Journal Articles
  • Parasites help find universal ecological rules [Ecology]
    [Feb 2015]

    Approximately half of all species are parasites. Further, parasites can strongly influence individuals, populations, and even communities. It should therefore be axiomatic to consider parasites in efforts to develop ecological principles meant to characterize all species (1, 2). However, all too often, our general empirical and theoretical work neglects parasites....
    Categories: Journal Articles
  • Birds tune in [Psychological and Cognitive Sciences]
    [Feb 2015]

    Imagine a friend telling you how she recently bought a goat. Why would your friend possibly buy a goat, you wonder—or had she actually said she bought a coat? Usually, listeners spend little time deciding whether someone had talked about a goat or a coat, or a pet or a...
    Categories: Journal Articles
  • Climate and cultural linkages in eastern Mexico [Anthropology]
    [Feb 2015]

    There is currently no consensus on the importance of climate change in Mesoamerican prehistory. Some invoke drought as a causal factor in major cultural transitions, including the abandonment of many sites at 900 CE, while others conclude that cultural factors were more important. This lack of agreement reflects the fact...
    Categories: Journal Articles