Physical activity-related energy expenditure with the RT3 and TriTrac accelerometers in overweight adults

Objective: The objective was to evaluate two accelerometers, the RT3 and the TriTrac‐R3D for their ability to produce estimates of physical activity‐related energy expenditure (PAEE) in overweight/obese adults. Research Methods and Procedures: PAEE estimates from both accelerometers were obtained in two experiments. In Experiment 1, 13 overweight/obese subjects (BMI 34.2 ± 6.4 kg/m²) were monitored over 2 weeks in everyday life, PAEE being simultaneously measured by the doubly labeled water method (DLW). In Experiment 2, 8 overweight/obese subjects (BMI 34.3 ± 5.0 kg/m²) and 10 normal‐weight subjects (BMI 20.8 ± 2.1 kg/m²) were monitored during a treadmill walking protocol, PAEE being simultaneously measured by indirect calorimetry. Results: In Experiment 1, there was no significant difference between methods in mean PAEE (DLW: 704 ± 223 kcal/d, RT3: 656 ± 140 kcal/d, TriTrac‐R3D 624 ± 419 kcal/d). The relative difference between methods (accelerometer vs. DLW) was ?17.1% ± 16.7% for the RT3 and ?20.0 ± 44.6% for the TriTrac‐R3D. Correlation for PAEE between RT3 and DLW was higher than between TriTrac‐R3D and DLW (r = 0.67, p < 0.05 and r = 0.36, p = 0.25, respectively). The 95% confidence interval (CI) (kcal/d) of the mean difference between methods was large, amounting to ?385 to 145 for the RT3 and ?887 to 590 for the TriTrac‐R3D. In Experiment 2, both accelerometers were sensitive to the changes in treadmill speed, with no significant difference in mean PAEE between methods in overweight/obese subjects. Conclusions: Although both accelerometers did not provide accurate estimates of PAEE at individual levels, the data suggest that RT3 has the potential to assess PAEE at group levels in overweight/obese subjects.     

Seasonal variation of carrageenan yield,gel strength and viscosity in Sarcopeltis (ex Gigartina) skottsbergii from Southern Chile

Chile is one of the top carrageenan producers worldwide, and Sarcopeltis (ex Gigartina) skottsbergii one of the topmost exploited carrageenophytes from the wild in the world. Total yield, gel strength and viscosity from two contrasting environments Calbuco and Ancud (Inner and Outer Sea, Chile) were estimated monthly in approximately 2 years for this species. While carrageenan yields did not show differences between localities, gametophytes in spring–summer had 15% higher, compared to tetrasporophytes. Sizes (frond surface) normally did not affect carrageenan yields. Gametophytes showed clear differences in gel strength between seasons, but not between localities, with maximum peaks during winter–spring months in Calbuco and autumn-winter months in Ancud. Seasonal variations in viscosity were also significant. While gametophyte viscosity did not exceed 120 cPs, tetrasporophytes reached 1400 cPs in Calbuco and 1000 cPs in Ancud. More remarkably, a positive correlation between viscosity and gel strength was found in S. skottsbergii gametophytes, which is significantly different between both localities. These results suggest that selective harvesting in spring–summer should be preferred to optimize cost–benefit of harvesting activities and subsequent carrageenan productivity.     

Crystal structure of the vitamin D nuclear receptor ligand binding domain in complex with a locked side chain analog of calcitriol

The crystal structures of vitamin D nuclear receptor (VDR) have revealed that all compounds are anchored by the same residues to the ligand binding pocket (LBP). Based on this observation, a synthetic analog with a locked side chain (21-nor-calcitriol-20(22),23-diyne) has been synthesized in order to gain in entropy energy with a predefined active side chain conformation. The crystal structure of VDR LBD bound to this locked side chain analogue while confirming the docking provides a structural basis for the activity of this compound.     

Adaptability of the Vitamin D nuclear receptor to the synthetic ligand Gemini: remodelling the LBP with one side chain rotation

The crystal structure of the ligand binding domain (LBD) of the wild-type Vitamin D receptor (VDR) of zebrafish bound to Gemini, a synthetic agonist ligand with two identical side chains branching at carbon 20 reveals a ligand-dependent structural rearrangement of the ligand binding pocket (LBP). The rotation of a Leu side chain opens the access to a channel that can accommodate the second side chain of the ligand. The 25% increase of the LBP's volume does not alter the essential agonist features of VDR. The possibility to adapt the LBP to novel ligands with different chemistry and/or structure opens new perspectives in the design of more specifically targeted ligands.     

SIGNR3‐dependent immune regulation by Lactobacillus acidophilus surface layer protein A in colitis

Intestinal immune regulatory signals govern gut homeostasis. Breakdown of such regulatory mechanisms may result in inflammatory bowel disease (IBD). Lactobacillus acidophilus contains unique surface layer proteins (Slps), including SlpA, SlpB, SlpX, and lipoteichoic acid (LTA), which interact with pattern recognition receptors to mobilize immune responses. Here, to elucidate the role of SlpA in protective immune regulation, the NCK2187 strain, which solely expresses SlpA, was generated. NCK2187 and its purified SlpA bind to the C-type lectin SIGNR3 to exert regulatory signals that result in mitigation of colitis, maintenance of healthy gastrointestinal microbiota, and protected gut mucosal barrier function. However, such protection was not observed in Signr3^−/− mice, suggesting that the SlpA/SIGNR3 interaction plays a key regulatory role in colitis. Our work presents critical insights into SlpA/SIGNR3-induced responses that are integral to the potential development of novel biological therapies for autoinflammatory diseases, including IBD.     

Tumor necrosis factor-alpha causes barrier dysfunction mediated by tyrosine198 and tyrosine218 in beta-actin

We tested the hypothesis that tumor necrosis factor-alpha (TNF) induces barrier dysfunction of pulmonary microvessel endothelial monolayers (PMEM) mediated by specific tyrosine residues in beta-actin. PMEM were transfected with a wild-type, mutant [tyrosine(198) to phenylalanine(198) (Y198F)], mutant Y218F, or mutant Y306F beta-actin construct tagged with enhanced yellow fluorescent protein (EYFP-beta-actin). The cellular compartmentalization of wild-type and mutant EYFP-beta-actin was displayed using EYFP fluorescence of the tagged beta-actin. beta-Actin was quantified for the EYFP-tagged and native beta-actin using Western blot assay. The effect of the EYFP-beta-actin on a cell junction protein was assessed by association of EYFP-beta-actin with beta-catenin using confocal microscopy and coimmunoprecipitation. The permeability of PMEM was assessed by the clearance rate of Evans blue-labeled albumin. The cellular compartmentalization of wild-type and mutant EYFP-beta-actin was similar to the native beta-actin. Incubation of PMEM with TNF (100 ng/ml) for 0.5 h resulted in increases in permeability to albumin and a decrease in association of the EYFP-beta-actin with beta-catenin. However, the expression of the EYFP-Y198F beta-actin and EYFP-Y218F beta-actin prevented the effect of TNF on beta-catenin and barrier function. The vehicle, wild-type EYFP-beta-actin, and mutant Y306F beta-actin had no affect on the response to TNF. The data indicate that TNF induces an increase in endothelial permeability that is dependent on tyrosine(198) and tyrosine(218) in beta-actin.