Increased Expression of Genes Involved in Fe-S Cluster Biosynthesis in Atfh Deficient Plants

Iron-Sulfur cluster are cofactors of proteins involved in central biochemical pathways and their assembly, and the maturation Fe-S proteins requires complex cellular machineries. The are three different systems for the biogenesis of bacterial Fe-S proteins: The NIF system for specific maturation of nitrogenase in azototrophic bacteria; and the ISC assembly and SUF system for the generation of housekeeping Fe-S proteins under normal and oxidative stress conditions, respectively. In eukaryotes, mitochondria are the primary site of cluster formation of most Fe-S proteins. Assembly of the Fe-S cluster is mediated by ISC machinery (Iron Sulphate Cluster assembly). In our laboratory we have characterized different genes and proteins that are postulated to be involved in the Fe-S cluster biosynthesis in Arabidopsis thaliana. AtNfs1 (Cysteine desulphurase, sulphur donor), AtFH (frataxin, iron donor); Isu1 (Scaffold protein); HscB (co-chaperone) and HscA (heat Shock protein). In this work we evaluate the effect of the deficiency of AtFH in the expression of the genes mentioned above. We measured the transcript level of these genes by QPCR in mutants plants of A.thaliana, Knock down(atfh-1) and antisense (as-atfh). All analized transcripts were increased (2 to 8-fold). However, some iron-sulfur proteins such as aconitase or succinate deshidrogenase were decreased in its catalytic activity. Our results are in agreement with a role of frataxin in the biogenesis of Fe-S proteins in plants

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

Background: The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications. Methods: ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery. Results: The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784. Conclusions: This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance. © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.Medical Research Council of South Africa gran