A pilot crossover study: effects of an intervention using an activity monitor with computerized game functions on physical activity and body composition

Background

Wearing an activity monitor as a motivational tool and incorporating a behavior-based reward system or a computerized game element might have a synergistic effect on an increase in daily physical activity, thereby inducing body fat reduction. This pilot crossover study aimed to examine the effects of a short-term lifestyle intervention using an activity monitor with computerized game functions on physical activity and body composition.

Methods

Twenty healthy volunteers (31 ± 3 years) participated in a 12-week crossover study. The participants were randomly assigned to either Group A (a 6-week game intervention followed by a 6-week normal intervention) or Group B (a 6-week normal intervention followed by a 6-week game intervention). The participants wore both a normal activity monitor (Lifecorder EX) and an activity monitor with computerized game functions (Yuuhokei) during the game intervention, whereas they only wore a normal activity monitor during the normal intervention. Before, during, and after the intervention, body composition was assessed.

Results

Significantly more daily steps were recorded for the game intervention than for the normal intervention (10,520 ± 562 versus 8,711 ± 523 steps/day, P < 0.01). The participants performed significantly more physical activity at an intensity of ≥ 3 metabolic equivalents (METs) in the game intervention than in the normal intervention (3.1 ± 0.2 versus 2.4 ± 0.2 METs · hour/day, P < 0.01). Although body mass and fat were significantly reduced in both periods (P < 0.01), the difference in body fat reduction was significantly greater in the game intervention than in the normal intervention (P < 0.05).

Conclusions

A short-term intervention using an activity monitor with computerized game functions increases physical activity and reduces body fat more effectively than an intervention using a standard activity monitor.     

Direct observation of minimum-sized amyloid fibrils using solution NMR spectroscopy

It is challenging to investigate the structure and dynamics of amyloid fibrils at the residue and atomic resolution because of their high molecular weight and heterogeneous properties. Here, we used solution nuclear magnetic resonance (NMR) spectroscopy to characterize the conformation and flexibility of amyloid fibrils of β2-microglobulin (β2m), for which direct observation of solution NMR could not be made. Ultrasonication led to fragmentation producing a solution of minimum-sized fibrils with a molecular weight of around 6 MDa. In 1H-15N heteronuclear single-quantum correlation measurements, five signals, derived from N-terminal residues (i.e., Ile1, Gln2, Arg3, Thr4, and Lys6), were newly detected. Signal strength decreased with the distance from the N-terminal end. Capping experiments with the unlabeled β2m monomer indicated that the signals originated from molecules located inside the fibrils. Ultrasonication makes the residues with moderate flexibility observable by reducing size of the fibrils. Thus, solution NMR measurements of ultrasonicated fibrils will be promising for studying the structure and dynamics of fibrils.     

<Emphasis Type="Italic">Caenorhabditis elegans</Emphasis> chromosome arms are anchored to the nuclear membrane via discontinuous association with LEM-2

Background  

Although Caenorhabditis elegans was the first multicellular organism with a completely sequenced genome, how this genome is arranged within the nucleus is not known.     

A derivative of lipid A is involved in signal recognition particle/SecYEG-dependent and -independent membrane integrations

A cell-free system was developed that allows the correct integration of single and multispanning membrane proteins of Escherichia coli into proteoliposomes. We found that physiological levels of diacylglycerol were required to prevent spontaneous integration into liposomes even of the polytopic mannitol permease. Using diacylglycerol-containing proteoliposomes, we identified a novel integration-stimulating factor. Integration of mannitol permease was dependent on both the SecYEG translocon and this factor and was mediated by signal recognition particle and signal recognition particle receptor. Integration of M13 procoat, which is independent of both signal recognition particle/signal recognition particle receptor and SecYEG, was also promoted by this factor. Furthermore, the factor stimulated the post-translational translocation of presecretory proteins, suggesting that it also mediates integration of a signal sequence. This factor was found to be a lipid A-derived membrane component possessing a peptide moiety.     

Quasielastic Light-Scattering Study on Changes in Sizes of Native White Membranes after Addition of Retinal

Aqueous suspensions of native white membranes from Halobacterium halobium, strain JW2N, have been studied by quasielastic light scattering. The intensity autocorrelation functions of polarized scattered light from suspensions of white membranes themselves and of white membranes after reconstitution with retinal were measured at various K², K being the magnitude of the scattering vector. The first cumulant or the average decay rate of the correlation function was obtained by a cumulant expansion method. The first cumulant for the white membranes increased after retinal was added to the suspension. The first cumulants obtained before and after the addition of retinal were almost independent of pH in the range 7 to 11, and of temperature in the range 15° to 40°C after T/η scaling, η being the solvent viscosity. This suggests that photocycling in reconstituted membranes, induced by the probe laser-beam, did not cause any detectable change in spectra, and that the membrane flexibility, if present, was independent of the above conditions, so that the spectral changes after the addition of retinal could be attributed mostly to the changes in the sizes of the membranes. A theoretical formulation for the first cumulant for a rigid disk-like scatterer (Fujime, S. and K. Kubota, 1985, Biophys. Chem., 23:1-13.) was applied to the analysis of the spectra. The results suggest that the radii of the membrane patches decreased by several percent after the addition of retinal.     

Gene transfer into intact plant cells by electroinjection through cell walls and membranes

Tobacco mosaic virus (TMV) RNA was introduced directly into mesophyll cells of Nicotiana tabacum var. Samsun using electric-field pulses (electroinjection). The injected gene was successfully expressed in the recipient cells as judged by the assay for the virus coat protein using immunofluorescence and by the virus infectivity assay of the homogenate of the electroinjected cells for local lesions on tobacco leaves. As much as 50% of the cells that survived 24 days after electroinjection showed immunofluorescent specks.     

Selective extraction of antenna chlorophylls, carotenoids and quinones from photosystem I reaction center

By the ether treatment of lyophilized PSI pigment-protein complexes, all the carotenoids and the secondary acceptor phylloquinone (A1), and more than 90% of the Chl were removed to yield the PSI complex with 9-11 molecules of Chl per reaction-center unit. The complexes retained the primary electron donor and acceptor (P700 and A0), in addition to three FeS clusters (F(X), F(A) and F(B)), and showed an activity of highly efficient electron transfer when phylloquinone was reconstituted. The methods for the preparation and the characterization of the ether-extracted PSI complexes are reviewed in this article. We also review the studies done with this PSI preparation on (1) the identification of the absorption and fluorescence spectra of P700, (2) the nano- and picosecond reaction of A0 and A1, (3) the energy-gap dependency of the reaction rate between A0 and the artificial quinones reconstituted at the A1 site, (4) the direct excitation of P700 followed by the ultra-fast electron transfer from P700 to A0, and (5) the de- and re-stabilization of the PSI structure by the removal and reconstitution, respectively, of antenna Chl in the presence of certain lipids.