Loss of the Nutrient Sensor Tas1R3 Leads to Reduced Bone Resorption

Background: The Taste receptor, type 1 (TAS1R) family of heterotrimeric G protein-coupled receptors participates in monitoring energy and nutrient needs. TAS1R member 3 (TAS1R3) either recognizes amino acids such as glycine and L-glutamate or sweet molecules such as sucrose and fructose when dimerized with TAS1R member 1 (TAS1R1) or TAS1R member 2 (TAS1R2), respectively. Loss of TAS1R3 expression can cause impaired mTORC1 signaling and increased autophagy, indicating that signaling through this receptor is critical for assessing nutrient needs. Recently, it was reported that global deletion of TAS1R3 expression in Tas1R3 mutant mice leads to increased cortical bone mass and trabecular remodeling but the underlying cellular mechanism leading to this phenotype remains unclear. Results: To address this open question, we quantified bone turnover markers in serum from 20-week-old wild type and Tas1R3 mutant mice and found that levels of the resorption marker Collagen Type I C-telopeptide (CTx) were reduced on average by \u3e60% in the absence of TAS1R3 expression. Levels of the bone formation marker Procollagen Type I N-terminal Propeptide (P1NP) tend to be higher in Tas1R3 mutant mice but this finding did not reach statistical significance (

Loss of the nutrient sensor TAS1R3 leads to reduced bone resorption

The taste receptor type 1 (TAS1R) family of heterotrimeric G protein-coupled receptors participates in monitoring energy and nutrient status. TAS1R member 3 (TAS1R3) is a bi-functional protein that recognizes amino acids such as L-glycine and L-glutamate or sweet molecules such as sucrose and fructose when dimerized with TAS1R member 1 (TAS1R1) or TAS1R member 2 (TAS1R2), respectively. It was recently reported that deletion of TAS1R3 expression in Tas1R3 mutant mice leads to increased cortical bone mass but the underlying cellular mechanism leading to this phenotype remains unclear. Here, we independently corroborate the increased thickness of cortical bone in femurs of 20-week-old male Tas1R3 mutant mice and confirm that Tas1R3 is expressed in the bone environment. Tas1R3 is expressed in undifferentiated bone marrow stromal cells (BMSCs) in vitro and its expression is maintained during BMP2-induced osteogenic differentiation. However, levels of the bone formation marker procollagen type I N-terminal propeptide (PINP) are unchanged in the serum of 20-week-old Tas1R3 mutant mice as compared to controls. In contrast, levels of the bone resorption marker collagen type I C-telopeptide are reduced greater than 60% in Tas1R3 mutant mice. Consistent with this, Tas1R3 and its putative signaling partner Tas1R2 are expressed in primary osteoclasts and their expression levels positively correlate with differentiation status. Collectively, these findings suggest that high bone mass in Tas1R3 mutant mice is due to uncoupled bone remodeling with reduced osteoclast function and provide rationale for future experiments examining the cell-type-dependent role for TAS1R family members in nutrient sensing in postnatal bone remodeling

Untitled

Woman wearing a blue dress and top hat, with a brown dog below her.https://commons.und.edu/uac-all/4045/thumbnail.jp

Untitled

Abstract, non-representational, over-sizedhttps://commons.und.edu/uac-all/3282/thumbnail.jp

The effect of ultrasound on electrochenical processes : dye effluent remediation and the anodic behaviour of copper

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Purely ultrasonic enzyme extraction from activated sludge in an ultrasonic cleaning bath

Enzymes are important in biological wastewater treatment systems, since they are responsible for breakdown of macro- and micropollutants, thereby making the pollutants available for metabolism. Enzyme activity has been investigated in particular in activated sludge processes, since the activated sludge technology is the most important and widely spread wastewater treatment technology used today. Various methods have been used to extract enzymes from activated sludge in order to measure their activity, these include stirring with additives like detergents and cation exchange resins, ultrasonication (with probes) and combinations of the three [1–3]. In this article we describe a method for purely ultrasonic enzyme extraction from activated sludge using low power ultrasound generated by an ultrasonic bath and no additives. The method essentially consists of: • Sonication of the sludge sample using a glass beaker and an ultrasonic bath. • Filtration of the sample in order to obtain the enzyme extract. • Measurement of enzyme activity by fluorescence spectrometry using a substrate that yields a fluorescent product