Effect of retirement on eating out and weight change: an analysis of gender differences

Objectives: The objectives were to understand how the retirement decisions of older Americans influence household food consumption patterns by gender and, in turn, to examine the impact of the change in food consumption on weight. Research Methods and Procedures: This study used five waves of the Health and Retirement Study (1992 to 2002; n = 28,117). Participants were 50 to 71 years old during the study period. We used longitudinal regression analyses controlling for health events, spousal factors, socioeconomic factors, and individual fixed effects over time. Results: Retirement of the individual and of his/her spouse reduced the individual's monthly spending on eating out by $10 and $7 on average, respectively, but did not change household spending on food at home. The wife's, but not the husband's, retirement decreased the spouse's spending on eating out by $13/mo. Spending on eating out was a significant but weak (0.003BMI/$) predictor of weight gain. Discussion: The decrease in spending on eating out after retirement, particularly women's, suggests that people eat out less when they have more time for food preparation at home. However, increases in other risks of weight gain with retirement, such as physical inactivity, could counteract the effects of eating out less.     

Rise of oceanographic barriers in continuous populations of a cetacean: the genetic structure of harbour porpoises in Old World waters

Background

Understanding the role of seascape in shaping genetic and demographic population structure is highly challenging for marine pelagic species such as cetaceans for which there is generally little evidence of what could effectively restrict their dispersal. In the present work, we applied a combination of recent individual-based landscape genetic approaches to investigate the population genetic structure of a highly mobile extensive range cetacean, the harbour porpoise in the eastern North Atlantic, with regards to oceanographic characteristics that could constrain its dispersal.

Results

Analyses of 10 microsatellite loci for 752 individuals revealed that most of the sampled range in the eastern North Atlantic behaves as a 'continuous' population that widely extends over thousands of kilometres with significant isolation by distance (IBD). However, strong barriers to gene flow were detected in the south-eastern part of the range. These barriers coincided with profound changes in environmental characteristics and isolated, on a relatively small scale, porpoises from Iberian waters and on a larger scale porpoises from the Black Sea.

Conclusion

The presence of these barriers to gene flow that coincide with profound changes in oceanographic features, together with the spatial variation in IBD strength, provide for the first time strong evidence that physical processes have a major impact on the demographic and genetic structure of a cetacean. This genetic pattern further suggests habitat-related fragmentation of the porpoise range that is likely to intensify with predicted surface ocean warming.     

Common marmosets are sensitive to simple dependencies at variable distances in an artificial grammar

Recognizing that two elements within a sequence of variable length depend on each other is a key ability in understanding the structure of language and music. Perception of such interdependencies has previously been documented in chimpanzees in the visual domain and in human infants and common squirrel monkeys with auditory playback experiments, but it remains unclear whether it typifies primates in general. Here, we investigated the ability of common marmosets (Callithrix jacchus) to recognize and respond to such dependencies. We tested subjects in a familiarization-discrimination playback experiment using stimuli composed of pure tones that either conformed or did not conform to a grammatical rule. After familiarization to sequences with dependencies, marmosets spontaneously discriminated between sequences containing and lacking dependencies (‘consistent’ and ‘inconsistent’, respectively), independent of stimulus length. Marmosets looked more often to the sound source when hearing sequences consistent with the familiarization stimuli, as previously found in human infants. Crucially, looks were coded automatically by computer software, avoiding human bias. Our results support the hypothesis that the ability to perceive dependencies at variable distances was already present in the common ancestor of all anthropoid primates (Simiiformes).     

Immunological and microbiological activity of Davilla elliptica St. Hill. (Dilleniaceae) against Mycobacterium tuberculosis

Mycobacterium tuberculosis is responsible for over 8 million cases of tuberculosis (TB) annually. Natural products may play important roles in the chemotherapy of TB. The immunological activity of Davilla elliptica chloroform extract (DECE) was evaluated in vitro by the determination of hydrogen peroxide (H2O2), nitric oxide (NO), and tumor necrosis factor-alpha (TNF-alpha) release in peritoneal macrophages cultures. DECE was also tested for its antimycobacterial activity against M. tuberculosis using the microplate alamar blue assay. DECE (50, 150, 250 microg/ml) stimulated the production of H2O2 (from 1,79 +/- 0,23 to 7,27 +/- 2,54; 15,02 +/- 2,86; 20,5 +/- 2,1 nmols) (means +/- SD), NO (from 2,64 +/- 1,02 to 25,59 +/- 2,29; 26,68 +/- 2,41; 29,45 +/- 5,87 micromols) (means +/- SD) and TNF-alpha (from 2,44 +/- 1,46 to 30,37 +/- 8,13; 38,68 +/- 1,59; 41,6 +/- 0,90 units/ml) (means +/- SD) in a dose-dependent manner and also showed a promising antimycobacterial activity with a minimum inhibitory concentration of 62,5 microg/ml. This plant may have therapeutic potential in the immunological and microbiological control of TB.     

The Role of Community and Individuals in the Formation of Social Capital

Because social capital shapes many desirable socioeconomic outcomes, we ask what incentives drive private investments in social capital. We estimate the association between private investments in social capital (outcome variable) and the following explanatory variables: (a) individual-level variables from an optimal investment model, (b) spillovers from group social capital, (c) village income inequality, and (d) market openness. We draw on information from Tsimane’, a native Amazonian society of foragers and farmers in Bolivia, and equate social capital with gifts, help given, and communal labor offered by the household. Age bore an inverted U-shaped and income bore a positive association with social capital, but geographic mobility, wealth, and schooling bore no significant association with social capital. We found strong group-level associations even after instrumenting social capital; the association probably stems from strong kinship ties which tend to blur the line between the group and the individual. Village measures of social capital were positively and significantly associated with private investments in social capital. We found some evidence that village income inequality and market openness were negatively associated with private investments in social capital.     

Fetal bovine serum enables cardiac differentiation of human embryonic stem cells

During development, cardiac commitment within the mesoderm requires endoderm-secreted factors. Differentiation of embryonic stem cells into the three germ layers in vitro recapitulates developmental processes and can be influenced by supplements added to culture medium. Hence, we investigated the effect of fetal bovine serum (FBS) and KnockOut serum replacement (SR) on germ layers specification and cardiac differentiation of H1 human embryonic stem cells (hESC) within embryoid bodies (EB). At the time of EB formation, FBS triggered an increased apoptosis. As assessed by quantitative PCR on 4-, 10-, and 20-day-old EB, FBS promoted a faster down-regulation of pluripotency marker Oct4 and an increased expression of endodermal (Sox17, alpha-fetoprotein, AFP) and mesodermal genes (Brachyury, CSX). While neuronal and hematopoietic differentiation occurred in both supplements, spontaneously beating cardiomyocytes were only observed in FBS. Action potential (AP) morphology of hESC-derived cardiomyocytes indicated that ventricular cells were present only after 2 months of culture. However, quantification of myosin light chain 2 ventricular (mlc2v)-positive areas revealed that mlc2v-expressing cardiomyocytes could be detected already after 2 weeks of differentiation, but not in all beating clusters. In conclusion, FBS enabled cardiac differentiation of hESC, likely in an endodermal-dependent pathway. Among cardiac cells, ventricular cardiomyocytes differentiated over time, but not as the predominant cardiac cell subtype.     

Molecular basis for PP2A regulatory subunit B56alpha targeting in cardiomyocytes

Protein phosphatase 2A (PP2A) is a multifunctional protein phosphatase with critical roles in excitable cell signaling. In the heart, PP2A function is linked with modulation of beta-adrenergic signaling and has been suggested to regulate key ion channels and transporters including Na/Ca exchanger, ryanodine receptor, inositol 1,4,5-trisphosphate receptor, and Na/K ATPase. Although many of the functional roles and molecular targets for PP2A in heart are known, little is established regarding the cellular pathways that localize specific PP2A isoform activities to subcellular sites. We report that the PP2A regulatory subunit B56alpha is an in vivo binding partner for ankyrin-B, an adapter protein required for normal subcellular localization of the Na/Ca exchanger, Na/K ATPase, and inositol 1,4,5-trisphosphate receptor. Ankyrin-B and B56alpha are colocalized and coimmunoprecipitate in primary cardiomyocytes. Using multiple strategies, we identified the structural requirements on B56alpha for ankyrin-B association as a 13 residue motif in the B56alpha COOH terminus not present in other B56 family polypeptides. Finally, we report that reduced ankyrin-B expression in primary ankyrin-B(+/-) cardiomyocytes results in disorganized distribution of B56alpha that can be rescued by exogenous expression of ankyrin-B. These new data implicate ankyrin-B as a critical targeting component for PP2A in heart and identify a new class of signaling proteins targeted by ankyrin polypeptides.     

Characterization of stem cells from the murine adult mammary gland

The postnatal mammary morphogenesis comprises two steps, first, formation of a system of branching ducts at puberty and second, alveologenesis during pregnancy. The mammary epithelium is organized as a bilayer, composed of two cellular types, basal myoepithelial and luminal epithelial. The remarkable regenerative properties revealed in serial transplantation experiments suggest that the adult mammary epithelium harbors stem cells. Various strategies including analysis of DNA label-retaining cells, transgenic approach, and in vivo transplantation assay, have been used to isolate and characterize murine mammary stem and progenitor cells. Their molecular characteristics remain to be defined precisely but notable progress have been already made in the enrichment and identification of these cells. Current studies favor the hypothesis of a basal-type mammary stem cells expressing high levels of alpha 6, beta1 and beta 3 integrin chains, the major receptors of extracellular matrix proteins. Luminal-type progenitors may participate in the establishment of the bilayered alveolar epithelium during pregnancy.     

Superantigen natural affinity maturation revealed by the crystal structure of staphylococcal enterotoxin G and its binding to T-cell receptor Vbeta8.2

The illnesses associated with bacterial superantigens (SAgs) such as food poisoning and toxic shock syndrome, as well as the emerging threat of purpura fulminans and community-associated methicillin-resistant S. aureus producer of SAgs, emphasize the importance of a better characterization of SAg binding to their natural ligands, which would allow the development of drugs or biological reagents able to neutralize their action. SAgs are toxins that bind major histocompatibility complex class II molecules (MHC-II) and T-cell receptors (TCR), in a nonconventional manner, inducing T-cell activation that leads to production of cytokines such as tumor necrosis factor and interleukin-2, which may result in acute toxic shock. Previously, we cloned and expressed a new natural variant of staphylococcal enterotoxin G (SEG) and evaluated its ability to stimulate in vivo murine T-cell subpopulations. We found an early, strong, and widespread stimulation of mouse Vbeta8.2 T-cells when compared with other SAgs member of the SEB subfamily. In search for the reason of the strong mitogenic potency, we determined the SEG crystal structure by X-ray crystallography to 2.2 A resolution and analyzed SEG binding to mVbeta8.2 and MHC-II. Calorimetry and SPR analysis showed that SEG has an affinity for mVbeta8.2 40 to 100-fold higher than that reported for other members of SEB subfamily, and the highest reported for a wild type SAg-TCR couple. We also found that mutations introduced in mVbeta8.2 to produce a high affinity mutant for other members of the SEB subfamily do not greatly affect binding to SEG. Crystallographic analysis and docking into mVbeta8.2 in complex with SEB, SEC3, and SPEA showed that the deletions and substitution of key amino acids remodeled the putative surface of the mVbeta8.2 binding site without affecting the binding to MHC-II. This results in a SAg with improved binding to its natural ligands, which may confer a possible evolutionary advantage for bacterial strains expressing SEG.     

Feature-based attention modulates orientation-selective responses in human visual cortex

How does feature-based attention modulate neural responses? We used adaptation to quantify the effect of feature-based attention on orientation-selective responses in human visual cortex. Observers were adapted to two superimposed oblique gratings while attending to one grating only. We measured the magnitude of attention-induced orientation-selective adaptation both psychophysically, by the behavioral tilt aftereffect, and physiologically, using fMRI response adaptation. We found evidence for orientation-selective attentional modulation of neuronal responses-a lower fMRI response for the attended than the unattended orientation-in multiple visual areas, and a significant correlation between the magnitude of the tilt aftereffect and that of fMRI response adaptation in V1, the earliest site of orientation coding. These results show that feature-based attention can selectively increase the response of neuronal subpopulations that prefer the attended feature, even when the attended and unattended features are coded in the same visual areas and share the same retinotopic location.