Proceedings of the Natural Academy of Sciences

Proceedings of the National Academy of Sciences RSS feed -- current issue
  • Plausible reductions in future population growth [Biological Sciences]
    [Feb 2015]

    Bradshaw and Brook (1) conclude that a substantial slowing of global population growth is infeasible over this century short of drastic reductions in fertility, and therefore could not contribute much to lessening pressure on the environment. However, their methodology is too crude to produce credible results. Bradshaw and Brook’s (1)...
    Categories: Journal Articles
  • Population stabilization potential underestimated [Biological Sciences]
    [Feb 2015]

    Bradshaw and Brook’s report “Human population reduction is not a quick fix for environmental problems” (1) argues that plausible efforts to reduce birth rates will make little difference to the course of human population this century. Although they emphasize that population reduction is highly desirable from an environmental perspective, and...
    Categories: Journal Articles
  • Humans are too many to reduce quickly [Biological Sciences]
    [Feb 2015]

    O’Neill et al. (1) and O’Sullivan (2) argue that the results of our global population scenarios (3) are not credible. Here we demonstrate that their arguments are peripheral and that our conclusions are robust. Both O’Neill et al. (1) and O’Sullivan (2) overlook that the demographic rates we used were...
    Categories: Journal Articles
  • Nonprice incentives and energy conservation [Sustainability Science]
    [Feb 2015]

    In the electricity sector, energy conservation through technological and behavioral change is estimated to have a savings potential of 123 million metric tons of carbon per year, which represents 20% of US household direct emissions in the United States. In this article, we investigate the effectiveness of nonprice information strategies...
    Categories: Journal Articles
  • Membranes serve as allosteric activators of PLA2 [Biochemistry]
    [Feb 2015]

    Defining the molecular details and consequences of the association of water-soluble proteins with membranes is fundamental to understanding protein–lipid interactions and membrane functioning. Phospholipase A2 (PLA2) enzymes, which catalyze the hydrolysis of phospholipid substrates that compose the membrane bilayers, provide the ideal system for studying protein–lipid interactions. Our study focuses...
    Categories: Journal Articles
  • BvgA regulation of the B. pertussis fim3 promoter [Biochemistry]
    [Feb 2015]

    Two-component systems [sensor kinase/response regulator (RR)] are major tools used by microorganisms to adapt to environmental conditions. RR phosphorylation is typically required for gene activation, but few studies have addressed how and if phosphorylation affects specific steps during transcription initiation. We characterized transcription complexes made with RNA polymerase and the...
    Categories: Journal Articles
  • AKT pathway in melanoma drug resistance [Cell Biology]
    [Feb 2015]

    BRAF (v-raf murine sarcoma viral oncogene homolog B) inhibitors elicit a transient anti-tumor response in ∼80% of BRAFV600-mutant melanoma patients that almost uniformly precedes the emergence of resistance. Here we used a mouse model of melanoma in which melanocyte-specific expression of BrafV618E (analogous to the human BRAFV600E mutation) led to...
    Categories: Journal Articles
  • Functional capacities of human IgM memory B cells [Immunology and Inflammation]
    [Feb 2015]

    The generation and functions of human peripheral blood (PB) IgM+IgD+CD27+ B lymphocytes with somatically mutated IgV genes are controversially discussed. We determined their differential gene expression to naive B cells and to IgM-only and IgG+ memory B cells. This analysis revealed a high similarity of IgM+(IgD+)CD27+ and IgG+ memory B...
    Categories: Journal Articles
  • Fetal V{gamma}9V{delta}2 effectors [Immunology and Inflammation]
    [Feb 2015]

    γδ T cells are unconventional T cells recognizing antigens via their γδ T-cell receptor (TCR) in a way that is fundamentally different from conventional αβ T cells. γδ T cells usually are divided into subsets according the type of Vγ and/or Vδ chain they express in their TCR. T cells...
    Categories: Journal Articles
  • Reprogrammed hematopoiesis in cancer [Medical Sciences]
    [Feb 2015]

    Expansion of myeloid cells associated with solid tumor development is a key contributor to neoplastic progression. Despite their clinical relevance, the mechanisms controlling myeloid cell production and activity in cancer remains poorly understood. Using a multistage mouse model of breast cancer, we show that production of atypical T cell-suppressive neutrophils...
    Categories: Journal Articles
  • Crystal structure of TarM [Microbiology]
    [Feb 2015]

    Unique to Gram-positive bacteria, wall teichoic acids are anionic glycopolymers cross-stitched to a thick layer of peptidoglycan. The polyol phosphate subunits of these glycopolymers are decorated with GlcNAc sugars that are involved in phage binding, genetic exchange, host antibody response, resistance, and virulence. The search for the enzymes responsible for...
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  • Neural restoration via loop-based reinforcement [Neuroscience]
    [Feb 2015]

    High-frequency deep brain stimulation (HFS) is clinically recognized to treat parkinsonian movement disorders, but its mechanisms remain elusive. Current hypotheses suggest that the therapeutic merit of HFS stems from increasing the regularity of the firing patterns in the basal ganglia (BG). Although this is consistent with experiments in humans and...
    Categories: Journal Articles
  • Vessel normalization in tuberculosis granulomas [Engineering]
    [Feb 2015]

    Tuberculosis (TB) causes almost 2 million deaths annually, and an increasing number of patients are resistant to existing therapies. Patients who have TB require lengthy chemotherapy, possibly because of poor penetration of antibiotics into granulomas where the bacilli reside. Granulomas are morphologically similar to solid cancerous tumors in that they...
    Categories: Journal Articles
  • Multiplex genome safeguards in yeast [Genetics]
    [Feb 2015]

    Biocontainment may be required in a wide variety of situations such as work with pathogens, field release applications of engineered organisms, and protection of intellectual properties. Here, we describe the control of growth of the brewer’s yeast, Saccharomyces cerevisiae, using both transcriptional and recombinational “safeguard” control of essential gene function....
    Categories: Journal Articles
  • Reversion of exhausted CD8T cells by metformin [Immunology and Inflammation]
    [Feb 2015]

    Metformin, a prescribed drug for type 2 diabetes, has been reported to have anti-cancer effects; however, the underlying mechanism is poorly understood. Here we show that this mechanism may be immune-mediated. Metformin enabled normal but not T-cell–deficient SCID mice to reject solid tumors. In addition, it increased the number of...
    Categories: Journal Articles
  • Control of Igh locus V(D)J recombination [Immunology and Inflammation]
    [Feb 2015]

    Ig heavy chain (IgH) variable region exons are assembled from V, D, and J gene segments during early B-lymphocyte differentiation. A several megabase region at the “distal” end of the mouse IgH locus (Igh) contains hundreds of VHs, separated by an intergenic region from Igh Ds, JHs, and constant region...
    Categories: Journal Articles
  • Mitophagy confers resistance to Pseudomonas [Immunology and Inflammation]
    [Feb 2015]

    In the arms race of bacterial pathogenesis, bacteria produce an array of toxins and virulence factors that disrupt core host processes. Hosts mitigate the ensuing damage by responding with immune countermeasures. The iron-binding siderophore pyoverdin is a key virulence mediator of the human pathogen Pseudomonas aeruginosa, but its pathogenic mechanism...
    Categories: Journal Articles
  • Evolutionary game theory of cancer [Medical Sciences]
    [Feb 2015]

    The extensive intratumor heterogeneity revealed by sequencing cancer genomes is an essential determinant of tumor progression, diagnosis, and treatment. What maintains heterogeneity remains an open question because competition within a tumor leads to a strong selection for the fittest subclone. Cancer cells also cooperate by sharing molecules with paracrine effects,...
    Categories: Journal Articles
  • Suppress cancer relapse by stemness inhibition [Medical Sciences]
    [Feb 2015]

    Partial or even complete cancer regression can be achieved in some patients with current cancer treatments. However, such initial responses are almost always followed by relapse, with the recurrent cancer being resistant to further treatments. The discovery of therapeutic approaches that counteract relapse is, therefore, essential for advancing cancer medicine....
    Categories: Journal Articles
  • GPR17 and food intake [Medical Sciences]
    [Feb 2015]

    G protein-coupled receptor 17 (GPR17) was recently reported to be a Foxo1 target in agouti-related peptide (AGRP) neurons. Intracerebroventricular injection of GPR17 agonists induced food intake, whereas administration of an antagonist to the receptor reduced feeding. These data lead to the conclusion that pharmacological modulation of GPR17 has therapeutic potential...
    Categories: Journal Articles