Smart phone, smart science: how the use of smartphones can revolutionize research in cognitive science

Investigating human cognitive faculties such as language, attention, and memory most often relies on testing small and homogeneous groups of volunteers coming to research facilities where they are asked to participate in behavioral experiments. We show that this limitation and sampling bias can be overcome by using smartphone technology to collect data in cognitive science experiments from thousands of subjects from all over the world. This mass coordinated use of smartphones creates a novel and powerful scientific "instrument" that yields the data necessary to test universal theories of cognition. This increase in power represents a potential revolution in cognitive science.     

Identification of Three Novel Genetic Variants in the Melanocortin‐3 Receptor of Obese Children

The melanocortin‐3 receptor (MC3R), a G‐protein‐coupled receptor expressed in the hypothalamus, is a key component of the leptin‐melanocortin pathway that regulates energy homeostasis. It is suggested that an MC3R defect leads to an increased feed efficiency, by which nutrients are partitioned preferentially into fat. In this study, we hypothesized that early‐onset obesity could be induced by mutations in MC3R. To investigate this hypothesis, we screened the entire coding region of the MC3R gene for mutations in obese subjects. A total of 404 overweight and obese children and adolescents, 86 severely obese adults (BMI ≥40 kg/m²), and 150 normal‐weight control adults were included. Besides three synonymous coding variations in the MC3R gene (S69S, L95L, I226I), we were able to identify three novel heterozygous, nonsynonymous, coding mutations (N128S, V211I, L299V) in three unrelated obese children. None of these mutations were found in any of the control subjects. Functional studies assessing localization and signaling properties of the mutant receptors provided proof for impaired function of the L299V mutated receptor, whereas no conclusive evidence for functional impairment of the N128S and V211I mutated receptors could be established. First, these results provide supporting evidence for a role of the MC3R gene in the pathogenesis of obesity in a small subset of patients. Second, they show that caution is called for the interpretation of newly discovered mutations in MC3R.     

New perspectives in flooding research: the use of shade avoidance and Arabidopsis thaliana

BACKGROUND: Complete submergence of Rumex palustris leads to hyponastic (upward) petiole growth followed by enhanced petiole elongation. Previous pharmacological experiments have provided insights into the signal transduction pathway leading to this combined 'escape' response. It will, however, be difficult to gain further knowledge using these methods. Consequently, new approaches are required. SCOPE: Here we propose that different environmental signals resulting in similar phenotypes can help to understand better the submergence response. In this review, we show that both ethylene and shade induce similar growth responses in R. palustris and Arabidopsis thaliana. We illustrate how this can be exploited to unravel novel signalling components in submergence-induced elongation growth. Furthermore, we illustrate the potential of arabidopsis as a useful model in submergence research based on similarities with submergence-tolerant species such as R. palustris and the molecular opportunities it presents. This is illustrated by examples of current work exploring this concept. CONCLUSIONS: Incorporating different model systems, such as arabidopsis and shade avoidance, into submergence research can be expected to create powerful tools to unravel signal transduction routes determining submergence tolerance.     

A new polymorphism in the type II deiodinase gene is associated with circulating thyroid hormone parameters

Type II deiodinase (D2) is important in the regulation of local thyroid hormone bioactivity in certain tissues. D2 in skeletal muscle may also play a role in serum triiodothyronine (T(3)) production. In this study, we identified a polymorphism in the 5'-UTR of the D2 gene (D2-ORFa-Gly3Asp). We investigated the association of D2-ORFa-Gly3Asp, and of the previously identified D2-Thr92Ala polymorphism, with serum iodothyronine levels. D2-ORFa-Gly3Asp was identified by sequencing the 5'-UTR of 15 randomly selected individuals. Genotypes for D2-ORFa-Gly3Asp were determined in 156 healthy blood donors (age 46.3 +/- 12.2 yr) and 349 ambulant elderly men (age 77.7 +/- 3.5 yr) and related to serum iodothyronine and TSH levels. D2-ORFa-Asp(3) had an allele frequency of 33.9% in blood bank donors and was associated with serum thyroxine (T(4); Gly/Gly vs. Gly/Asp vs. Asp/Asp = 7.06 +/- 0.14 vs. 6.74 +/- 0.15 vs. 6.29 +/- 0.27 microg/dl, P = 0.01), free T(4) (1.22 +/- 0.02 vs. 1.16 +/- 0.02 vs. 1.06 +/- 0.04 ng/dl, P = 0.001), reverse T(3) (P = 0.01), and T(3)/T(4) ratio (P = 0.002) in a dose-dependent manner, but not with serum T(3) (P = 0.59). In elderly men, D2-ORFa-Asp(3) had a similar frequency but was not associated with serum iodothyronine levels. This new polymorphism in the 5'-UTR of D2 is associated with iodothyronine levels in blood donors but not in elderly men. We hypothesize that this might be explained by the decline in skeletal muscle size during aging, resulting in a relative decrease in the contribution of D2 to serum T(3) production.     

Genetic and physiological architecture of early vigor in Aegilops tauschii, the D-genome donor of hexaploid wheat. A quantitative trait loci analysis

Plant growth can be studied at different organizational levels, varying from cell, leaf, and shoot to the whole plant. The early growth of seedlings is important for the plant's establishment and its eventual success. Wheat (Triticum aestivum, genome AABBDD) seedlings exhibit a low early growth rate or early vigor. The germplasm of wheat is limited. Wild relatives constitute a source of genetic variation. We explored the physiological and genetic relationships among a range of early vigor traits in Aegilops tauschii, the D-genome donor. A genetic map was constructed with amplified fragment-length polymorphism and simple sequence repeat markers, and quantitative trait loci (QTL) analysis was performed on the F(4) population of recombinant inbred lines derived from a cross between contrasting accessions. The genetic map consisted of 10 linkage groups, which were assigned to the seven chromosomes and covered 68% of the D genome. QTL analysis revealed 87 mapped QTLs (log of the odds >2.65) in clusters, 3.1 QTLs per trait, explaining 32% of the phenotypic variance. Chromosomes 1D, 4D, and 7D harbored QTLs for relative growth rate, biomass allocation, specific leaf area, leaf area ratio, and unit leaf rate. Chromosome 2D covered QTLs for rate and duration of leaf elongation, cell production rate, and cell length. Chromosome 5D harbored QTLs for the total leaf mass and area and growth rate of the number of leaves and tillers. The results show that several physiological correlations between growth traits have a genetic basis. Genetic links between traits are not absolute, opening perspectives for identification of favorable alleles in A. tauschii to improve early vigor in wheat.     

Simian immunodeficiency virus infection in free-ranging sooty mangabeys (Cercocebus atys atys) from the Taï Forest, Côte d'Ivoire: implications for the origin of epidemic human immunodeficiency virus type 2

Simian immunodeficiency virus of sooty mangabeys (SIVsmm) is recognized as the progenitor of human immunodeficiency virus type 2 (HIV-2) and has been transmitted to humans on multiple occasions, yet the epidemiology and genetic diversity of SIVsmm infection in wild-living populations remain largely unknown. Here, we report the first molecular epidemiological survey of SIVsmm in a community of approximately 120 free-ranging sooty mangabeys in the Ta? Forest, C?te d'Ivoire. Fecal samples (n = 39) were collected from 35 habituated animals (27 females and 8 males) and tested for SIVsmm virion RNA (vRNA). Viral gag (800 bp) and/or env (490 bp) sequences were amplified from 11 different individuals (eight females and three males). Based on the sensitivity of fecal vRNA detection and the numbers of samples analyzed, the prevalence of SIVsmm infection was estimated to be 59% (95% confidence interval, 0.35 to 0.88). Behavioral data collected from this community indicated that SIVsmm infection occurred preferentially in high-ranking females. Phylogenetic analysis of gag and env sequences revealed an extraordinary degree of genetic diversity, including evidence for frequent recombination events in both the recent and distant past. Some sooty mangabeys harbored near-identical viruses (<2% interstrain distance), indicating epidemiologically linked infections. These transmissions were identified by microsatellite analyses to involve both related (mother/daughter) and unrelated individuals, thus providing evidence for vertical and horizontal transmission in the wild. Finally, evolutionary tree analyses revealed significant clustering of the Ta? SIVsmm strains with five of the eight recognized groups of HIV-2, including the epidemic groups A and B, thus pointing to a likely geographic origin of these human infections in the eastern part of the sooty mangabey range.     

Contrasting interactions between ethylene and abscisic acid in Rumex species differing in submergence tolerance

Complete submergence of flooding-tolerant Rumex palustris plants strongly stimulates petiole elongation. This escape response is initiated by the accumulation of ethylene inside the submerged tissue. In contrast, petioles of flooding-intolerant Rumex acetosa do not increase their elongation rate under water even though ethylene also accumulates when they are submerged. Abscisic acid (ABA) was found to be a negative regulator of enhanced petiole growth in both species. In R. palustris, accumulated ethylene stimulated elongation by inhibiting biosynthesis of ABA via a reduction of RpNCED expression and enhancing degradation of ABA to phaseic acid. Externally applied ABA inhibited petiole elongation and prevented the upregulation of gibberellin A(1) normally found in submerged R. palustris. In R. acetosa submergence did not stimulate petiole elongation nor did it depress levels of ABA. However, if ABA concentrations in R. acetosa were first artificially reduced, submergence (but not ethylene) was then able to enhance petiole elongation strongly. This result suggests that in Rumex a decrease in ABA is a prerequisite for ethylene and other stimuli to promote elongation.     

Mechanical and failure properties of single attached cells under compression

Eukaryotic cells are continuously subjected to mechanical forces under normal physiological conditions. These forces and associated cellular deformations induce a variety of biological processes. The degree of deformation depends on the mechanical properties of the cell. As most cells are anchorage dependent for normal functioning, it is important to study the mechanical properties of cells in their attached configuration. The goal of the present study was to obtain the mechanical and failure properties of attached cells. Individual, attached C2C12 mouse myoblasts were subjected to unconfined compression experiments using a recently developed loading device. The device allows global compression of the cell until cell rupture and simultaneously measures the associated forces. Cell bursting was characterized by a typical reduction in the force, referred to as the bursting force. Mean bursting forces were calculated as 8.7+/-2.5 microN at an axial strain of 72+/-4%. Visualization of the cell using confocal microscopy revealed that cell bursting was preceded by the formation of bulges at the cell membrane, which eventually led to rupturing of the cell membrane. Finite element calculations were performed to simulate the obtained force-deformation curves. A finite element mesh was built for each cell to account for its specific geometrical features. Using an axisymmetric approximation of the cell geometry, and a Neo-Hookean constitutive model, excellent agreement between predicted and measured force-deformation curves was obtained, yielding an average Young's modulus of 1.14+/-0.32 kPa.     

New simian immunodeficiency virus infecting De Brazza's monkeys (Cercopithecus neglectus): evidence for a cercopithecus monkey virus clade

Nearly complete sequences of simian immunodeficiency viruses (SIVs) infecting 18 different nonhuman primate species in sub-Saharan Africa have now been reported; yet, our understanding of the origins, evolutionary history, and geographic distribution of these viruses still remains fragmentary. Here, we report the molecular characterization of a lentivirus (SIVdeb) naturally infecting De Brazza's monkeys (Cercopithecus neglectus). Complete SIVdeb genomes (9,158 and 9227 bp in length) were amplified from uncultured blood mononuclear cell DNA of two wild-caught De Brazza's monkeys from Cameroon. In addition, partial pol sequences (650 bp) were amplified from four offspring of De Brazza's monkeys originally caught in the wild in Uganda. Full-length (9068 bp) and partial pol (650 bp) SIVsyk sequences were also amplified from Sykes's monkeys (Cercopithecus albogularis) from Kenya. Analysis of these sequences identified a new SIV clade (SIVdeb), which differed from previously characterized SIVs at 40 to 50% of sites in Pol protein sequences. The viruses most closely related to SIVdeb were SIVsyk and members of the SIVgsn/SIVmus/SIVmon group of viruses infecting greater spot-nosed monkeys (Cercopithecus nictitans), mustached monkeys (Cercopithecus cephus), and mona monkeys (Cercopithecus mona), respectively. In phylogenetic trees of concatenated protein sequences, SIVdeb, SIVsyk, and SIVgsn/SIVmus/SIVmon clustered together, and this relationship was highly significant in all major coding regions. Members of this virus group also shared the same number of cysteine residues in their extracellular envelope glycoprotein and a high-affinity AIP1 binding site (YPD/SL) in their p6 Gag protein, as well as a unique transactivation response element in their viral long terminal repeat; however, SIVdeb and SIVsyk, unlike SIVgsn, SIVmon, and SIVmus, did not encode a vpu gene. These data indicate that De Brazza's monkeys are naturally infected with SIVdeb, that this infection is prevalent in different areas of the species' habitat, and that geographically diverse SIVdeb strains cluster in a single virus group. The consistent clustering of SIVdeb with SIVsyk and the SIVmon/SIVmus/SIVgsn group also suggests that these viruses have evolved from a common ancestor that likely infected a Cercopithecus host in the distant past. The vpu gene appears to have been acquired by a subset of these Cercopithecus viruses after the divergence of SIVdeb and SIVsyk.