Keithliu9629

RtcB is a noncanonical RNA ligase that joins either 2',3'-cyclic phosphate or 3'-phosphate termini to 5'-hydroxyl termini. The genes encoding RtcB and Archease constitute a tRNA splicing operon in many organisms. Archease is a cofactor of RtcB that accelerates RNA ligation and alters the NTP specificity of the ligase from Pyrococcus horikoshii. Yet, not all organisms that encode RtcB also encode Archease. Here we sought to understand the differences between Archease-dependent and Archease-independent RtcBs so as to illuminate the evolution of Archease and its function. We report on the Archease-dependent RtcB from Thermus thermophilus and the Archease-independent RtcB from Thermobifida fusca. We find that RtcB from T. thermophilus can catalyze multiple turnovers only in the presence of Archease. Remarkably, Archease from P. horikoshii can activate T. thermophilus RtcB, despite low sequence identity between the Archeases from these two organisms. In contrast, RtcB from T. fusca is a single-turnover enzyme that is unable to be converted into a multiple-turnover ligase by Archease from either P. horikoshii or T. thermophilus. Thus, our data indicate that Archease likely evolved to support multiple-turnover activity of RtcB and that coevolution of the two proteins is necessary for a functional interaction.The founding heterochronic microRNAs, lin-4 and let-7, together with their validated targets and well-characterized phenotypes in C. elegans, offer an opportunity to test functionality of microRNAs in a developmental context. In this study, we defined sequence requirements at the microRNA level for these two microRNAs, evaluating lin-4 and let-7 mutant microRNAs for their ability to support temporal development under conditions where the wild-type lin-4 and let-7 gene products are absent. For lin-4, we found a strong requirement for seed sequences, with function drastically affected by several central mutations in the seed sequence, while rescue was retained by a set of mutations peripheral to the seed. let-7 rescuing activity was retained to a surprising degree by a variety of central seed mutations, while several non-seed mutant effects support potential noncanonical contributions to let-7 function. Taken together, this work illustrates both the functional partnership between seed and non-seed sequences in mediating C. elegans temporal development and a diversity among microRNA effectors in the contributions of seed and non-seed regions to activity.Pistol RNAs are members of a distinct class of self-cleaving ribozymes that was recently discovered by using a bioinformatics search strategy. Several hundred pistol ribozymes share a consensus sequence including 10 highly conserved nucleotides and many other modestly conserved nucleotides associated with specific secondary structure features, including three base-paired stems and a pseudoknot. A representative pistol ribozyme from the bacterium Lysinibacillus sphaericus was found to promote RNA strand scission with a rate constant of ∼10 min(-1) under physiological Mg(2+) and pH conditions. The reaction proceeds via the nucleophilic attack of a 2'-oxygen atom on the adjacent phosphorus center, and thus adheres to the same general catalytic mechanism of internal phosphoester transfer as found with all other classes of natural self-cleaving ribozymes discovered to date. Analyses of the kinetic characteristics and the metal ion requirements of the cleavage reaction reveal that members of this ribozyme class likely use several catalytic strategies to promote the rapid cleavage of RNA.

Chronic dysglycemia was recently identified as a predictor for adverse outcomes in patients with ST-elevation myocardial infarction (STEMI) treated by percutaneous coronary intervention. Data for non-diabetic patients who underwent thrombolysis is scarce. In this context, we aimed to study the effect of HbA1c on cardiovascular outcome after STEMI.

A prospective cohort of 326 non-diabetic STEMI individuals was used for the analyses. We measured plasma glucose, hemoglobin A1c [HbA1c], lipid profile, C-reactive protein (CRP), and nitrate/nitrite (NOx) upon admission and five days after STEMI (D5). Flow-mediated dilation (FMD) was performed 30 days after STEMI. During clinical follow-up, we assessed patients for incident diabetes (progression to HbA1c ≥ 6.5%) and major adverse cardiac events (MACE), defined as a composite of fatal and non-fatal MI, sudden cardiac death, and angina requiring hospitalization.

Using ROC-curve analysis, a 5.8% HbA1c best predicted MACE with a sensitivity of 75% and specificity of 53% (AUC 0.673, p = 0.001). Patients were categorized as high HbA1c if ≥ 5.8% and low HbA1c if <5.8%. Compared with patients with low HbA1c, those with high HbA1c presented with 20% higher CRP-D5 (p = 0.009) and 19% higher ΔCRP (p = 0.01), a 32% decrease in ΔNOx (p < 0.001), and 33% lower FMD (p < 0.001). After a median follow-up of 1.9 (1.1-2.8) years, patients with high HbA1c had more incident diabetes (HR 2.3 95% CI 1.01-5.2; p = 0.048) and MACE (HR 3.32 95% CI 1.09-10.03; p = 0.03).

Non-diabetic STEMI patients with high HbA1c present with decreased endothelial function and increased inflammatory response and long-term risk of MACE.

Non-diabetic STEMI patients with high HbA1c present with decreased endothelial function and increased inflammatory response and long-term risk of MACE.Thermal inactivation kinetics of Hypocrea orientalis β-glucosidase and effect of glucose on thermostability of the enzyme have been determined in this paper. Kinetic studies showed that the thermal inactivation was irreversible and first-order reaction. The microscopic rate constants for inactivation of free enzyme and substrate-enzyme complex were both determined, which suggested that substrates can protect β-glucosidase against thermal deactivation effectively. On the other hand, glucose was found to protect β-glucosidase from heat inactivation to remain almost whole activity below 70°C at 20mM concentration, whereas the apparent inactivation rate of BG decreased to be 0.3×10(-3)s(-1) in the presence of 5mM glucose, smaller than that of sugar-free enzyme (1.91×10(-3)s(-1)). The intrinsic fluorescence spectra results showed that glucose also had stabilizing effect on the conformation of BG against thermal denaturation. Docking simulation depicted the interaction mode between glucose and active residues of the enzyme to produce stabilizing effect.Chitosan has become a popular polymer for drug delivery. It's hydro solubility and mild formulation conditions have made it an attractive polymer for macromolecular delivery. Accurate quantification of internalized chitosan nanoparticles (NPs) is imperative for fair assessment of the nano-formulation where it is important to determine the exact amount of drug actually being delivered into the cell, especially for macromolecular drugs where cellular entry is limited by molecule size and/or charge. The preferential affinity of wheat germ agglutinin tagged with fluorescein isothiocyanate (WGA-FITC) to chitosan is exploited in the development of a simple and rapid method for the differentiation between and quantification of cell surface bound and internalized chitosan NPs. The percentage of cell surface bound NPs could be easily determined and corrected NP uptake could be calculated accordingly. The developed method is applicable in several cell lines and has successfully been tested with NPs with different sizes (25 and 150nm) and with very low NP concentrations (20μg/mL). The method will allow for the correct evaluation of chitosan NP uptake and could be further used to evaluate chitosan based nanomedicine and provide guidelines on how to modify NPs for enhanced internalization, and improved drug delivery.A new porous magnetic chitosan modified by melamine (MA-CS/Fe3O4) was synthesized. The compositions and surface topographies were characterized by infrared (IR) spectroscopy, X-ray diffraction (XRD) analysis, thermogravimetric (TG) analysis and scanning electron microscope (SEM), respectively. The results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation (R>0.999). The adsorption isotherm was well fitted by the Langmuir equation (R>0.999), and the values of separation factors were in the range of 0-1.0. The maximum adsorption capacity for Cu(II) was 2.58mmolg(-1) at the optimal experimental conditions, which were pH=5.5, t=25min, C0=5.0mmolL(-1). The rate-controlling step was supposed to be chemical adsorption rather than mass transport. The adsorbent still exhibited high adsorption capacity after five regeneration cycles. The adsorption mechanism was due to coordination between Cu(II) and N atoms.Activation, the state of possessing the skills, knowledge, and confidence to manage one's own health, is associated with positive self-management behaviors in individuals with chronic illness. Little is known about its role in cancer survivorship. The aims of this study were to describe activation in patients with colorectal cancer and their family caregivers, examine the relationship between patient and caregiver activation, and determine whether activation is related to symptom distress, depression, anxiety, fatigue, physical activity, and work productivity. Using a longitudinal, correlational design, a convenience sample of 62 patients and 42 family caregivers completed surveys during postoperative hospitalization, and at 6 weeks and 4 months postop. Activation scores for both patients and caregivers were stable over time, were not correlated, and were at the third level of activation. Linear mixed effects models revealed that negative emotions were associated with less patient activation and lower caregiver self-efficacy for caring for oneself.Sarcopenia is a major contributor to the loss of independence and deteriorating quality of life in elderly individuals, it manifests as a decline in skeletal muscle mass and strength beyond the age of 65. Muscle fibre atrophy is a major contributor to sarcopenia and the most severely atrophic fibres are commonly found in elderly muscles to have permanently lost their motor nerve input. By contrast with elderly fibres, when fibres in young animals lose their motor input they normally mount a response to induce restoration of nerve contact, and this is mediated in part by upregulated expression of the nerve cell adhesion molecule (NCAM). Therefore, skeletal muscles appear to progressively lose their ability to become reinnervated, and here we have investigated whether this decline occurs via loss of the muscle's ability to upregulate NCAM in response to denervation. We performed partial denervation (by peripheral nerve crush) of the extensor digitorum longus muscle of the lower limb in both young and elderly ming ability to mount a normal response to loss of motor input.Long-term insulin delivery can reduce blood glucose variability in diabetic patients. In this study, its impact on oxidative stress status, inflammation, and liver injury was investigated. Diabetes was induced in Wistar rats with a single dose of streptozotocin (100 mg/kg). Untreated rats and rats administered Insuplant® (2 UI/200 g/day) through a subcutaneous osmotic pump for one or four weeks were compared with non-diabetic controls. Body weight, fructosamine level, total cholesterol, Insulin Growth Factor-1 (IGF-1) level, lipid peroxidation, and total antioxidant capacity were measured. Hepatic injury was determined through the measurement of glycogen content, reactive oxygen species (ROS) production, and macrophage infiltration. Liver oxidative stress status was evaluated through the measurement of superoxide dismutase (SOD), catalase (CAT), and nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) expression, and p38 mitogen-activated protein kinase (p38MAPK) activation. read more Induction of diabetes led to increased plasma oxidative stress and inflammation.