Development of an Accelerometer-Linked Online Intervention System to Promote Physical Activity in Adolescents

Most adolescents do not achieve the recommended levels of moderate-to-vigorous physical activity (MVPA), placing them at increased risk for a diverse array of chronic diseases in adulthood. There is a great need for scalable and effective interventions that can increase MVPA in adolescents. Here we report the results of a measurement validation study and a preliminary proof-of-concept experiment testing the impact of Zamzee, an accelerometer-linked online intervention system that combines proximal performance feedback and incentive motivation features to promote MVPA. In a calibration study that parametrically varied levels of physical activity in 31 12-14 year-old children, the Zamzee activity meter was shown to provide a valid measure of MVPA (sensitivity in detecting MVPA = 85.9%, specificity = 97.5%, and r = .94 correspondence with the benchmark RT3 accelerometer system; all p < .0001). In a subsequent randomized controlled multi-site experiment involving 182 middle school-aged children assessed for MVPA over 6 wks, intent-to-treat analyses found that those who received access to the Zamzee intervention had average MVPA levels 54% greater than those of a passive control group (p < 0.0001) and 68% greater than those of an active control group that received access to a commercially available active videogame (p < .0001). Zamzee’s effects on MVPA did not diminish significantly over the course of the 6-wk study period, and were statistically significant in both females and males, and in normal- vs. high-BMI subgroups. These results provide promising initial indications that combining the Zamzee activity meter with online proximal performance feedback and incentive motivation features can positively impact MVPA levels in adolescents.     

Transfer of intracolonial genetic variability through gametes in Acropora hyacinthus corals

In recent years, the new phenomenon of intracolonial genetic variability within a single coral colony has been described. This connotes that coral colonies do not necessarily consist of only a single genotype, but may contain several distinct genotypes. Harboring more than one genotype could improve survival under stressful environmental conditions, e.g., climate change. However, so far it remained unclear whether the intracolonial genetic variability of the adult coral is also present in the gametes. We investigated the occurrence of intracolonial genetic variability in 14 mature colonies of the coral Acropora hyacinthus using eight microsatellite loci. A grid was placed over each colony before spawning, and the emerging egg/sperm bundles were collected separately in each grid. The underlying tissues as well as the egg/sperm bundles were genotyped to determine whether different genotypes were present. Within the 14 mature colonies, we detected 10 colonies with more than one genotype (intracolonial genetic variability). Four out of these 10 mature colonies showed a transfer of different genotypes via the eggs to the next generation. In two out of these four cases, we found additional alleles, and in the two other cases, we found only a subset of alleles in the unfertilized eggs. Our results suggest that during reproduction of A. hyacinthus, more than one genotype per colony is able to reproduce. We discuss the occurrence of different genotypes within a single coral colony and the ability for those to release eggs which are genetically distinct.     

Indication of dynamic neurovascular coupling from inconsistency between EEG and fMRI indices across sleep–wake states

Sleep and Biological Rhythms - Neurovascular coupling (NVC), the transient regional hyperemia following the evoked neuronal responses, is the basis of blood oxygenation level-dependent techniques...     

Comparing the use of leaf and cambium tissue in a single genetic study of tropical trees

Amplified fragment length polymorphisms (AFLPs) are a useful molecular tool for studying species with little available genetic information; however, since universal primers are used contaminant DNA from non-target organisms may also be amplified. Cambium tissue may contain fewer biotic contaminants or plant defense chemicals, than the more commonly used leaf tissue, and therefore be more suitable for use as a source of DNA when using universal primers. On the other hand, cambium tissue can be difficult to identify, yields low DNA and requires the bark of the tree to be damaged, thereby increasing the risk of introducing disease. We show that within two tropical tree species, there are few differences between AFLP profiles obtained from either cambium or leaf tissue from the same tree. We studied 50 Brosimum alicastrum individuals at 119 AFLP loci and 40 Swietenia macrophylla individuals at 112 AFLP loci. The matrix of S?rensen similarity indices between individual AFLP profiles for cambium samples was strongly correlated to the matrix for leaf samples in each species (Mantel test; B. alicastrum r = 0.815, P < 0.001; S. macrophylla r = 0.895, P < 0.001). The phylogenetic relationship between the trees studied did not differ dependent on tissue type used and therefore shows that both tissues can be used within a single study without introducing substantial error.     

Inhibition of yeast binding to mouse peritoneal macrophages by wheat germ agglutinin: a novel effect of the lectin on phagocytic cells

The ability of wheat germ agglutinin (WGA) to enhance the binding of bacteria and tumor cells to phagocytic cells, and to induce the killing of tumor cells by macrophages and monocytes, is well established. We observed, however, that WGA inhibits the binding to and phagocytosis of yeast cells by thioglycolate-elicited murine peritoneal macrophages. In order to follow these processes rapidly, the yeasts were labeled with Congo-red and their binding to the macrophages was measured spectrophotometrically after treatment with sodium dodecylsulfate. Phagocytosis was also followed by light microscopy. Binding of the yeasts was inhibited by about 80% after pretreating the macrophages with 150 micrograms/ml of WGA. This effect was reversed by subsequent incubation with N-acetyl-D-glucosamine, chitobiose or chitotriose, but was unaffected by methyl alpha-D-mannoside, N-acetyl-D-mannosamine, D-mannose or D-galactose. Pretreatment of the Congo-red yeasts with WGA did not inhibit their binding by the macrophages. Of a variety of lectins tested, only WGA and Datura stramonium lectin had this effect. Pretreating the macrophages with sialidase prevented the inhibition induced by WGA. Our findings suggest the presence on the macrophages of a class of WGA receptors not previously reported.     

Crystallization and preliminary X-ray diffraction studies of the lectin from Erythrina corallodendron

The lectin from Erythrina corallodendron, specific for N-acetyllactosamine, crystallizes in the hexagonal space group P6(1) (P6(5)) with unit cell dimensions a = b = 136.3 A, c = 83.2 A and one dimer of Mr 60,000 in the asymmetric unit. The crystals are suitable for high-resolution work.     

The Catecholaminergic Polymorphic Ventricular Tachycardia Mutation R33Q Disrupts the N-terminal Structural Motif That Regulates Reversible Calsequestrin Polymerization

Calsequestrin undergoes dynamic polymerization with increasing calcium concentration by front-to-front dimerization and back-to-back packing, forming wire-shaped structures. A recent finding that point mutation R33Q leads to lethal catecholaminergic polymorphic ventricular tachycardia (CPVT) implies a crucial role for the N terminus. In this study, we demonstrate that this mutation resides in a highly conserved alternately charged residue cluster (DGKDR; cluster 1) in the N-terminal end of calsequestrin. We further show that this cluster configures itself as a ring system and that the dipolar arrangement within the cluster brings about a critical conformational flip of Lys³¹-Asp³² essential for dimer stabilization by formation of a H-bond network. We additionally show that Ca²⁺-induced calsequestrin aggregation is nonlinear and reversible and can regain the native conformation by Ca²⁺ chelation with EGTA. This study suggests that cluster 1 works as a molecular switch and governs the bidirectional transition between the CASQ2 monomer and dimer. We further demonstrate that mutations disrupting the alternating charge pattern of the cluster, including R33Q, impair Ca²⁺-CASQ2 interaction, leading to altered polymerization-depolymerization dynamics. This study provides new mechanistic insight into the functional effects of the R33Q mutation and its potential role in CPVT.     

Antigenicity of UV radiation-induced murine tumors correlates positively with the level of adenosine deaminase activity

Summary The specific activities of adenosine deaminase (ADA) in 16 murine tumor cell lines derived from seven UV light-induced neoplasms (melanoma and fibrosarcoma) were determined. In each case, the specific activity of ADA correlated positively with the antigenicity of the tumor cells. Highly antigenic cell lines that regress upon introduction into syngeneic hosts had on average 4- to 6-fold higher ADA specific activities than cell lines of low antigenicity that grow progressively in syngeneic hosts. The antigenic differences are probably not related to intracellular cAMP levels, as the level of cAMP differed only 2-fold between the two groups of cell lines.