A thorough understanding of the relevant cervical bony and soft tissue anatomy is
essential for safe implantation and a successful outcome.”
“Eutrophication degrades numerous estuaries worldwide and a myriad of assessment metrics have been developed. Here, we apply an example of a previously developed metric (Lee et al., 2004) designed to indicate incipient estuarine eutrophication to validate this technique in an already eutrophic estuary end-member, Barnegat Bay-Little Egg Harbor, New Jersey. The metric, termed ‘Nutrient Pollution Indicator’ (NPI) uses eelgrass (Zostera LBH589 order marina L) as a bioindicator and is calculated as the ratio of leaf nitrogen content (%N) to area normalized leaf mass (mg dry wt cm(-2)). Eelgrass samples were collected along the entire length of the Barnegat Bay-Little Egg Harbor from June to October 2008 to determine if leaf chemistry and morphology reflect eutrophication status and a north-south gradient of nitrogen loading from the Barnegat Bay watershed. Nitrogen content, area normalized leaf mass, and NPI values all significantly (p < 0.05) varied temporally but not spatially. NPI values did not significantly correspond to the north-south gradient of nitrogen loading from the Barnegat Bay
watershed. The NPI metric is therefore not deemed to reliably indicate estuarine eutrophic status. Differences between sampling effort (number of stations) and replication did not bias the overall conclusions. (C) 2011 Elsevier B.V. All rights reserved.”
“Pseudouridine synthases introduce the most common RNA modification and likely use the same MRT67307 cost catalytic mechanism. Besides a catalytic aspartate residue, the contributions of other residues for catalysis of pseudouridine formation are poorly understood. Here,
we have tested the role of a conserved basic residue in the active site for catalysis using the bacterial pseudouridine Galardin ic50 synthase TruB targeting U55 in tRNAs. Substitution of arginine 181 with lysine results in a 2500-fold reduction of TruB’s catalytic rate without affecting tRNA binding. Furthermore, we analyzed the function of a second-shell aspartate residue (D90) that is conserved in all TruB enzymes and interacts with C56 of tRNA. Site-directed mutagenesis, biochemical and kinetic studies reveal that this residue is not critical for substrate binding but influences catalysis significantly as replacement of D90 with glutamate or asparagine reduces the catalytic rate 30- and 50-fold, respectively. In agreement with molecular dynamics simulations of TruB wild type and TruB D90N, we propose an electrostatic network composed of the catalytic aspartate (D48), R181 and D90 that is important for catalysis by fine-tuning the D48-R181 interaction. Conserved, negatively charged residues similar to D90 are found in a number of pseudouridine synthases, suggesting that this might be a general mechanism.