Vargas-Suarez M.,Ave University 3000 |
Castro-Sanchez A.,Ave University 3000 |
Toledo-Ortiz G.,Ave University 3000 |
Gonzalez De La Vara L.E.,CINVESTAV |
And 2 more authors.
Biochimie | Year: 2013
RNA-binding proteins (RNPs) participate in diverse processes of mRNA metabolism, and phosphorylation changes their binding properties. In spinach chloroplasts, 24RNP and 28RNP are associated with polynucleotide posphorylase forming a complex on charge of pre-mRNA 3′-end maturation. Here, we tested the hypothesis that the phosphorylation status of 24RNP and 28RNP, present in a spinach chloroplast mRNA 3′-UTR processing extract (CPE), controls the transition between petD precursor stabilization, 3′-UTR processing, and RNA degradation in vitro. The CPE processed or stabilized petD precursor depending on the ATP concentration present in an in vitro 3′-UTR processing (IVP) assay. These effects were also observed when ATP was pre-incubated and removed before the IVP assay. Moreover, a dephosphorylated (DP)-CPE degraded petD precursor and recovered 3′-UTR processing or stabilization activities in an ATP concentration dependent manner. To determine the role 24/28RNP plays in regulating these processes a 24/28RNP-depleted (Δ24/28)CPE was generated. The Δ24/28CPE degraded the petD precursor, but when it was reconstituted with recombinant non-phosphorylated (NP)-24RNP or NP-28RNP, the precursor was stabilized, whereas when Δ24/28CPE was reconstituted with phosphorylated (P)-24RNP or P-28RNP, it recovered 3′-UTR processing, indicating that 24RNP or 28RNP is needed to stabilize the precursor, have a redundant role, and their phosphorylation status regulates the transition between precursor stabilization and 3′-UTR processing. A DP-Δ24/28CPE reconstituted or not with NP-24/28RNP degraded petD precursor. Pre-incubation of DP-Δ24/28CPE with NP-24/28RNP plus 0.03 mM ATP recovered 3′-UTR processing activity, and its reconstitution with P-24/28RNP stabilized the precursor. However, pre-incubation of DP-Δ24/28CPE with 0.03 mM ATP, and further reconstitution with NP-24/28RNP or P-24/28RNP produced precursor stability instead of RNA degradation, and RNA processing instead of precursor stability, respectively. Moreover, in vitro phosphorylation of CPE showed that 24RNP, 28RNP, and other proteins may be phosphorylated. Altogether, these results reveal that phosphorylation of 24RNP, 28RNP, and other unidentified CPE proteins mediates the in vitro interplay between petD precursor stability, 3′-UTR processing, and degradation, and support the idea that protein phosphorylation plays an important role in regulating mRNA metabolism in chloroplast. © 2012 Elsevier Masson SAS. All rights reserved.
Rodriguez-Garcia G.,Autonomous University of the State of Hidalgo |
Andrade-Lopez N.,Autonomous University of the State of Hidalgo |
Alvarado-Rodriguez J.G.,Autonomous University of the State of Hidalgo |
Martinez-Otero D.,Autonomous University of the State of Hidalgo |
And 2 more authors.
Polyhedron | Year: 2011
Cis-[MLCl2] complexes of di-(2-pyridyl)pyrimidin-2- ylsulfanylmethane ligand (L), where M = Pd (1), and M = Pt (2) have been synthesized. Reaction of 1 with L in presence of Na[BF4] and hot acetonitrile produced the complex [PdL2](BF4)2 (3). Complexes 1-3 and ligand L have been characterized by elemental analyses, IR and NMR spectroscopy. Crystal structures of 1, 3 and L were determined by single crystal X-ray diffraction analyses, showing nonplanar structures with the pyridinic rings twisted around the bridging carbon and the ipso carbon bonds. 1 and 3 displayed a bidentate coordination of L to the palladium atom with the formation of six-membered chelate rings, where the local geometry at palladium atom was distorted square planar. In 3 the palladium atom was coordinated to two dipyridyl ligands through two of the pyridinic nitrogen atoms to form a cationic complex stabilized by two tetrafluoroborate counter-ions. © 2011 Elsevier Ltd. All rights reserved.
Sanchez-Mendiola M.,Ave University 3000 |
Morales-Castillo D.,Ave University 3000 |
Torruco-Garcia U.,Ave University 3000 |
Varela-Ruiz M.,Ave University 3000
BMC Medical Education | Year: 2015
Background: A time-honored strategy for keeping up to date in medicine and improving critical appraisal skills is the Journal Club (JC). There are several reports of its use in medicine and allied health sciences but almost no reports of JC focused on medical education. The purpose of the study is to describe and evaluate an eight years' experience with a medical education Journal Club (MEJC). Methods: We started a monthly medical education JC in 2006 at UNAM Faculty of Medicine in Mexico City. Its goal is to provide faculty with continuing professional development in medical education. A discussion guide and a published paper were sent 2 weeks before sessions. We reviewed the themes and publication types of the papers used in the sessions, and in June-July 2014 administered a retrospective post-then-pre evaluation questionnaire to current participants that had been regular attendees to the JC for more than 2 years. The retrospective post-then-pre comparisons were analyzed with Wilcoxon signed-rank test. Effect sizes were calculated for the pre-post comparisons with Cohen's r. Results: There have been 94 MEJC sessions until July 2014. Average attendance is 20 persons, a mix of clinicians, educators, psychologists and a sociologist. The articles were published in 32 different journals, and covered several medical education themes (curriculum, faculty development, educational research methodology, learning methods, assessment, residency education). 22 Attendees answered the evaluation instrument. The MEJC had a positive evaluation from good to excellent, and there was an improvement in self-reported competencies in medical education literature critical appraisal and behaviors related to the use of evidence in educational practice, with a median effect size higher than 0.5. The evaluation instrument had a Cronbach's alpha of 0.96. Conclusions: A periodic Medical Education Journal Club can improve critical appraisal of the literature, and be maintained long-term using evidence-based strategies. This activity is a useful adjunct to the scholarship of teaching. © 2015 Sánchez-Mendiola et al.
PubMed | Ave University 3000 and Ave University 3000 Cu
Type: | Journal: BMC medical education | Year: 2015
Biomedical Informatics (BMI) education in medical schools is developing a sound curricular base, but there are few published reports of their educational usefulness. The goal of this paper is to assess knowledge change and satisfaction in medical students after a BMI curriculum.The National Autonomous University of Mxico Faculty of Medicine (UNAM) recently implemented a curricular reform that includes two BMI sequential courses (BMI-1 and BMI-2). The research design was one-group pretest-posttest. An objective test with evidence of validity was used for knowledge measurement. A satisfaction questionnaire was applied at the end of the courses. Two-tailed paired Students t-tests were applied, comparing knowledge scores in the pre and post-test for each course.The study included student cohorts during two consecutive academic years. The 2013 BMI-1 course (n=986 students) knowledge pretest score was 43.08.6 (mean percent correctSD), and the post-test score was 57.710.3 (p<0.001); the 2014 BMI-1 (n=907) pretest score was 43.78.5, and the post-test was 58.110.5 (p<0.001). The 2012 BMI-2 course (n=683) pretest score was 26.37.9, the post-test score was 44.313.3 (p<0.001); the 2013 BMI-2 (n=926) pretest score was 27.57.5, and the post-test was 42.011.0 (p<0.001). The overall opinion of the students regarding the course was from good to excellent, with a response rate higher than 90%. The satisfaction questionnaires had high reliability (Cronbachs alpha of 0.93).The study shows a significant increase in BMI knowledge after an educational intervention in four medical student cohorts, and an overall positive evaluation by the students. Long-term follow-up is needed, as well as controlled studies of BMI educational interventions using performance endpoints.