Table Of Contents Page, PNAS Volume 103, Number 2

PNAS January 10, 2006

In This Issue

Commentary

Physical Sciences

Chemistry

The binding of small molecules to distinctive three-dimensional structures in mRNA provides a new dimension in RNA control, previously limited to the targeting of secondary structures with antisense and RNA interference; such targeting can modulate mRNA ...
The cycle of the photoactive yellow protein (PYP) has been extensively studied, but the dynamics of the isolated chromophore responsible for transduction is unknown. Here, we present real-time observation of the dynamics of the negatively charged ...

Physics

Although it is well described in model membranes, little is known about phase separation in biological membranes. Here, we provide evidence for a coexistence of at least two different lipid bilayer phases in the apical plasma membrane of epithelial cells. ...
Accurate cell division in Escherichia coli requires the Min proteins MinC, MinD, and MinE as well as the presence of nucleoids. MinD and MinE exhibit spatial oscillations, moving from pole to pole of the bacterium, resulting in an average MinD ...

Social Sciences

Psychology

The question of whether language affects perception has been debated largely on the basis of cross-language data, without considering the functional organization of the brain. The nature of this neural organization predicts that, if language affects ...

Social Sciences

Using historical data from cohorts born before the 20th century in four northern European countries, we show that increasing longevity and declining mortality in the elderly occurred among the same birth cohorts that experienced a reduction in mortality ...

Biological Sciences

Biochemistry

The binding of small molecules to distinctive three-dimensional structures in mRNA provides a new dimension in RNA control, previously limited to the targeting of secondary structures with antisense and RNA interference; such targeting can modulate mRNA ...
We describe the use of modified fluorescent-labeled oligonucleotide probes in the sequence-specific detection of messenger RNAs in live human cells. To make this detection possible, we developed a previously undescribed probe design that combines earlier ...
Water-specific aquaporins (AQP), such as the prototypical mammalian AQP1, stringently exclude the passage of solutes, ions, and even protons. Supposedly, this is accomplished by two conserved regions within the pore, a pair of canonical asparagine–proline–...
The interaction between enzymes of a nonribosomal peptide synthetase (NRPS) complex relies on the interplay of compatible sets of donor and acceptor communication-mediating (COM) domains. Hence, these domains are essential for the formation of a defined ...
Recent studies have revealed numerous examples in which oxidation and reduction of cysteines in proteins are integrated into specific cascades of biological regulatory systems. In general, these reactions proceed as thiol-disulfide exchange events. ...
The reaction of hypochlorous acid (HOCl) with hydrogen peroxide is known to generate stoichiometric amounts of singlet molecular oxygen [O2 (1Δg)]. This study shows that HOCl can also react with linoleic acid hydroperoxide (LAOOH), generating O2 (1Δg) ...
Ero1p is a key enzyme in the disulfide bond formation pathway in eukaryotic cells in both aerobic and anaerobic environments. It was previously demonstrated that Ero1p can transfer electrons from thiol substrates to molecular oxygen. However, the fate of ...
Bacterial cell-surface attachment of macromolecular complexes maintains the microorganism in close proximity to extracellular substrates and allows for optimal uptake of hydrolytic byproducts. The cellulosome is a large multienzyme complex used by many ...

Biophysics

The cycle of the photoactive yellow protein (PYP) has been extensively studied, but the dynamics of the isolated chromophore responsible for transduction is unknown. Here, we present real-time observation of the dynamics of the negatively charged ...
It has recently been demonstrated that many biological networks exhibit a “scale-free” topology, for which the probability of observing a node with a certain number of edges (k) follows a power law: i.e., p(k) ∼ k. This observation has been reproduced ...
Cytochrome c oxidase (CcO) is the terminal enzyme of the respiratory chain and couples energetically the reduction of oxygen to water to proton pumping across the membrane. The results from previous studies showed that proton pumping can be uncoupled from ...
The conservation of structure across homolog proteins often diffuses the impact of drug-based inhibition by promoting alternative protein-ligand associations that may lead to toxic side effects. However, sticky packing defects are typically not conserved ...

Cell Biology

Although it is well described in model membranes, little is known about phase separation in biological membranes. Here, we provide evidence for a coexistence of at least two different lipid bilayer phases in the apical plasma membrane of epithelial cells. ...
Receptor-operated Ca2+ entry (ROCE) and store-operated Ca2+ entry (SOCE) are known to be inhibited by tyrosine kinase inhibitors and activation of C-type transient receptor potential channel (TRPC) isoform 3 (TRPC3), a cation channel thought to be ...
Efficient targeting of proteins for degradation from the secretory pathway is essential to homeostasis. This occurs through endoplasmic reticulum (ER)-associated degradation (ERAD). In this study, we establish that a human ubiquitin ligase (E3), gp78, and ...
Accurate cell division in Escherichia coli requires the Min proteins MinC, MinD, and MinE as well as the presence of nucleoids. MinD and MinE exhibit spatial oscillations, moving from pole to pole of the bacterium, resulting in an average MinD ...
Presenilins (PS) are required for γ-secretase cleavage of multiple type I membrane proteins including the amyloid precursor protein and Notch and also have been implicated in regulating intracellular protein trafficking and turnover. Using genetic and ...

Developmental Biology

Nuclear-cytoplasmic partitioning and traffic between cytoplasmic and nuclear compartments are fundamental processes in eukaryotic cells. Nuclear pore complexes mediate transport of proteins, RNAs and ribonucleoprotein particles in and out of the nucleus. ...
Accumulating in vitro evidence suggests that the p38 mitogen-activated protein kinase (MAPK) pathway is involved in endochondral ossification. To investigate the role of this pathway in endochondral ossification, we generated transgenic mice with ...

Ecology

We use chronologies of stable isotopes measured from elephant (Loxodonta africana) hair to determine migration patterns and seasonal diet changes in elephants in and near Samburu National Reserve in northern Kenya. Stable carbon isotopes record diet ...
Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and patterns of spread. However, there is no consensus ...

Evolution

The “false thumb” of pandas is a carpal bone, the radial sesamoid, which has been enlarged and functions as an opposable thumb. If the giant panda (Ailuropoda melanoleuca) and the red panda (Ailurus fulgens) are not closely related, their sharing of this ...

Genetics

Centromeres have many unusual biological properties, including kinetochore attachment and severe repression of local meiotic recombination. These properties are partly an outcome, partly a cause, of unusual DNA structure in the centromeric region. ...
To understand the dynamics of transcriptional response to changing environments, well defined, easily controlled, and short-term perturbation experiments were undertaken. We subjected steady-state cultures of Saccharomyces cerevisiae in chemostats growing ...

Immunology

During humoral immune responses, two distinct genetic modification events diversify the Ig genes in germinal center (GC) B cells: somatic hypermutation and class switch recombination (CSR). Both processes require the activity of activation-induced ...

Medical Sciences

Twelve patients with T cell large granular lymphocyte leukemia and associated hematocytopenia were treated in a phase I dose-escalation trial with the murine monoclonal antibody Mikβ1. Mikβ1 identifies CD122, the β-subunit shared by the IL-2 and IL-15 ...
The molecular diversity of the luminal endothelial cell surface arising in vivo from local variations in genetic expression and tissue microenvironment may create opportunities for achieving targeted molecular imaging and therapies. Here, we describe a ...
The cAMP signaling pathway regulates growth of many cell types, including somatotrophs, thyrocytes, melanocytes, ovarian follicular granulosa cells, adrenocortical cells, and keratinocytes. Mutations of partners from the cAMP signaling cascade are ...
Plasmid-mediated gene therapy can restore dystrophin expression in skeletal muscle in the mdx mouse, a model of Duchenne muscular dystrophy. However, sufficient long-term expression and distribution of dystrophin remain a hurdle for translating this ...

Microbiology

Mycoplasma genitalium has the smallest genome of any organism that can be grown in pure culture. It has a minimal metabolism and little genomic redundancy. Consequently, its genome is expected to be a close approximation to the minimal set of genes needed ...
PA-824 is a promising new compound for the treatment of tuberculosis that is currently undergoing human trials. Like its progenitors metronidazole and CGI-17341, PA-824 is a prodrug of the nitroimidazole class, requiring bioreductive activation of an ...
High-risk human papillomaviruses (HPVs) (e.g., HPV-16) cause anogenital and head and neck cancers, and low-risk HPVs (e.g., HPV-6) cause benign hyperproliferative disease. The E7 protein of HPV-16 binds all retinoblastoma tumor suppressor protein (pRB) ...

Neuroscience

Epidemiological evidence suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the risk for Alzheimer's disease (AD). Certain NSAIDs can activate the peroxisome proliferator-activated receptor-γ (PPARγ), which is a nuclear transcriptional ...
Cortical analysis related to visual object recognition is traditionally thought to propagate serially along a bottom-up hierarchy of ventral areas. Recent proposals gradually promote the role of top-down processing in recognition, but how such ...
We visualized synchronous dynamic brain networks by using prewhitened (stationary) magnetoencephalography signals. Data were acquired from 248 axial gradiometers while 10 subjects fixated on a spot of light for 45 s. After fitting an autoregressive ...
The question of whether language affects perception has been debated largely on the basis of cross-language data, without considering the functional organization of the brain. The nature of this neural organization predicts that, if language affects ...

Pharmacology

Monocyte-to-macrophage differentiation with the cytokine granulocyte–macrophage colony-stimulating factor induces expression of the cyclic nucleotide phosphodiesterase PDE1B2. However, what role PDE1B2 plays in macrophage biology has not been elucidated. ...

Plant Biology

We show that MAX1, a specific repressor of vegetative axillary bud outgrowth in Arabidopsis, acts a positive regulator of the flavonoid pathway, including 11 structural genes and the transcription factor An2. Repression of bud outgrowth requires MAX1-...
State transition in photosynthesis is a short-term balancing mechanism of energy distribution between photosystem I (PSI) and photosystem II (PSII). When PSII is preferentially excited (state 2), a pool of mobile light-harvesting complex II (LHCII) ...

Psychology

Until half a century ago, associative learning played a fundamental role in theories of perceptual appearance [Berkeley, G. (1709) An Essay Towards a New Theory of Vision (Dublin), 1st Ed.]. But starting in 1955 [Gibson, J. J. & Gibson, E. J. (1955) ...

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