A Test of the Use of Timber Wolf (Canis lupus) Urine to Reduce Coyote (Canis latrans) Depredation Rates on Loggerhead Sea Turtle (Caretta caretta) Nests

Loggerhead sea turtles are currently listed as vulnerable by the International Union of Conservation of Nature (IUCN) with a decreasing population trend. Over the past four years, coyotes (Canis latrans) have depredated 24.18% of loggerhead sea turtle (Caretta caretta) nests on the night they were laid on South Island beach at the Tom Yawkey Wildlife Center, near Georgetown, SC. This has resulted in an estimated 4,002 eggs lost each year there. Over that time, a South Carolina Department of Natural Resources (SCDNR) Turtle Technician Team patrolled the beach at dawn every morning to cage and catalog loggerhead eggs and nests but were unable to cost-effectively protect the nests the night the eggs are laid. To test a new method to dissuade coyote depredation, I used dispensers filled with wolf urine to simulate timber wolf (Canis lupus) activity on seven sections of the beach and left seven sections untreated as controls

The regulation of carbamoyl phosphate synthetase-aspartate transcarbamoylase-dihydroorotase (CAD) by phosphorylation and protein-protein interactions

Pyrimidines have many important roles in cellular physiology, as they are used in the formation of DNA, RNA, phospholipids, and pyrimidine sugars. The first rate-limiting step in the de novo pyrimidine synthesis pathway is catalyzed by the carbamoyl phosphate synthetase II (CPSase II) part of the multienzymatic complex Carbamoyl phosphate synthetase, Aspartate transcarbamoylase, Dihydroorotase (CAD). CAD gene induction is highly correlated to cell proliferation. Additionally, CAD is allosterically inhibited or activated by uridine triphosphate (UTP) or phosphoribosyl pyrophosphate (PRPP), respectively. The phosphorylation of CAD by PKA and ERK has been reported to modulate the response of CAD to allosteric modulators. While there has been much speculation on the identity of CAD phosphorylation sites, no definitive identification of in vivo CAD phosphorylation sites has been performed. Therefore, we sought to determine the specific CAD residues phosphorylated by ERK and PKA in intact cells. We observed the PKA-induced phosphorylation of Ser1406 and Ser1859 HEK-293 cells. Surprisingly, while ERK phosphorylated CAD on multiple residues in vitro, CAD was not an ERK substrate in HEK-293 cells. We determined the identity of a previously unknown phosphopeptide in CAD isolated from HEK-293 cells. We also observed that the phosphorylation of CAD in HEK-293 cells is important for the maintenance of CPSase II activity. In addition to investigating the regulation of CAD by phosphorylation, we have identified a novel protein-protein interaction between CAD and the human cell cycle checkpoint protein hRad9. The interaction was mapped to the CPSase II portion of CAD, and the binding of hRad9 to CAD induced a significant activation of CPSase II activity. Taken together, these studies demonstrate novel mechanisms of CAD regulation in mammalian cells

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 (

The human Rad9 checkpoint protein stimulates the carbamoyl phosphate synthetase activity of the multifunctional protein CAD

The human Rad9 checkpoint protein is a subunit of the heterotrimeric Rad9-Rad1-Hus1 (9-1-1) complex that plays a role as a damage sensor in the DNA damage checkpoint response. Rad9 has been found to interact with several other proteins outside the context of the 9-1-1 complex with no obvious checkpoint functions. During our studies on the 9-1-1 complex, we found that Rad9 immunoprecipitates contained a 240 kDa protein that was identified as carbamoyl phosphate synthetase/aspartate transcarbamoylase/dihydroorotase (CAD), a multienzymatic protein required for the de novo synthesis of pyrimidine nucleotides and cell growth. Further investigations revealed that only free Rad9, but not Rad9 within the 9-1-1 complex, bound to CAD. The rate-limiting step in de novo pyrimidine nucleotide synthesis is catalyzed by the carbamoyl phosphate synthetase II (CPSase) domain of CAD. We find that Rad9 binds to the CPSase domain, and, moreover, this binding results in a 2-fold stimulation of the CPSase activity of CAD. Similar results were also obtained with an N-terminal Rad9 fragment. These findings suggest that Rad9 may play a role in ribonucleotide biosynthesis

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

Computación

Las hojas de cálculo electrónicas y microcomputadoras. Este programa esta basado para enseñar como se realizan las hojas de cálculo y como están compuestas también las reglas de cálculo