Regulation of Catalase-Peroxidase KatG Is OxyR Dependent and Fur Independent in Caulobacter crescentus

Most organisms that grow in the presence of oxygen possess catalases and/or peroxidases, which are necessary for scavenging the H(2)O(2) produced by aerobic metabolism. In this work we investigate the pathways that regulate the Caulobacter crescentus katG gene, encoding the only enzyme with catalase-peroxidase function in this bacterium. The transcriptional start site of the katG gene was determined, showing a short 5` untranslated region. The katG regulatory region was mapped by serial deletions, and the results indicate that there is a single promoter, which is responsible for induction at stationary phase. An oxyR mutant strain was constructed; it showed decreased katG expression, and no KatG protein or catalase-peroxidase activity was detected in stationary-phase cell extracts, implying that OxyR is the main positive regulator of the C. crescentus katG gene. Purified OxyR protein bound to the katG regulatory region between nucleotides -42 and -91 from the transcription start site, as determined by a DNase I footprinting assay, and a canonical OxyR binding site was found in this region. Moreover, OxyR binding was shown to be redox dependent, given that only oxidized proteins bound adjacent to the -35 sequence of the promoter and the katG P1 promoter was activated by OxyR in an H(2)O(2)-dependent manner. On the other hand, this work showed that the iron-responsive regulator Fur does not regulate C. crescentus katG, since a fur mutant strain presented wild-type levels of katG transcription and catalase-peroxidase production and activity, and the purified Fur protein was not able to bind to the katG regulatory region.

Clopidogrel, independent of the vascular P2Y(12) receptor, improves arterial function in small mesenteric arteries from Angll-hypertensive rats

The P2Y(12) receptor antagonist clopidogrel blocks platelet aggregation, improves systemic endothelial nitric oxide bioavailability and has anti-inflammatory effects. Since P2Y(12) receptors have been identified in the vasculature, we hypothesized that clopidogrel ameliorates Angll (angiotensin II)-induced vascular functional changes by blockade of P2Y(12) receptors in the vasculature. Male Sprague Dawley rats were infused with Angll (60 ng/min) or vehicle for 14 days. The animals were treated with clopidogrel (10 mg . kg(-1) of body weight . day(-1)) or vehicle. Vascular reactivity was evaluated in second-order mesenteric arteries. Clopidogrel treatment did not change systolic blood pressure [(mmHg) control-vehicle, 117 +/- 7.1 versus control-clopidogrel, 125 +/- 4.2; Angll vehicle, 197 +/- 10.7 versus Angll clopidogrel, 198 +/- 5.2], but it normalized increased phenylephrine-induced vascular contractions [(%KCI) vehicle-treated, 182.2 +/- 18% versus clopidogrel, 133 +/- 14%), as well as impaired vasodilation to acetylcholine [(%) vehicle-treated, 71.7 +/- 2.2 versus clopidogrel, 85.3 +/- 2.8) in Angll-treated animals. Vascular expression of P2Y(12) receptor was determined by Western blot. Pharmacological characterization of vascular P2Y(12) was performed with the P2Y(12) agonist 2-MeS-ADP [2-(methylthio) adenosine 5`-trihydrogen diphosphate trisodium]. Although 2-MeS-ADP induced endothelium-dependent relaxation [(Emax %) = 71 +/- 12%) as well as contractile vascular responses (Emax % = 83 +/- 12%), these actions are not mediated by P2Y(12) receptor activation. 2-MeS-ADP produced similar vascular responses in control and Angll rats. These results indicate potential effects of clopidogrel, such as improvement of hypertension-related vascular functional changes that are not associated with direct actions of clopidogrel in the vasculature, supporting the concept that activated platelets contribute to endothelial dysfunction, possibly via impaired nitric oxide bioavailability.

Robust linear mixed models with skew-normal independent distributions from a Bayesian perspective

Linear mixed models were developed to handle clustered data and have been a topic of increasing interest in statistics for the past 50 years. Generally. the normality (or symmetry) of the random effects is a common assumption in linear mixed models but it may, sometimes, be unrealistic, obscuring important features of among-subjects variation. In this article, we utilize skew-normal/independent distributions as a tool for robust modeling of linear mixed models under a Bayesian paradigm. The skew-normal/independent distributions is an attractive class of asymmetric heavy-tailed distributions that includes the skew-normal distribution, skew-t, skew-slash and the skew-contaminated normal distributions as special cases, providing an appealing robust alternative to the routine use of symmetric distributions in this type of models. The methods developed are illustrated using a real data set from Framingham cholesterol study. (C) 2009 Elsevier B.V. All rights reserved.

Sugarcane Phosphoribosyl Pyrophosphate Synthetase: Molecular Characterization of a Phosphate-independent PRS

Phosphoribosyl pyrophosphate synthetase (PRS-EC:2.7.6.1) is an important enzyme present in several metabolic pathways, thus forming a complex family of isoenzymes. However, plant PRS enzymes have not been extensively investigated. In this study, a sugarcane prs gene has been characterized from the Sugar Cane Expressed Sequence Tag Genome Project. This gene contains a 984-bp open reading frame encoding a 328-amino acid protein. The predicted amino acid sequence has 77% and 78% amino acid sequence identity to Arabidopsis thaliana and Spinacia oleracea PRS4, respectively. The assignment of sugarcane PRS as a phosphate-independent PRS isoenzyme (Class II PRS) is verified following enzyme assay and phylogenetic reconstruction of PRS homologues. To gain further insight into the structural framework of the phosphate independence of sugarcane PRS, a molecular model is described. This model reveals the formation of two conserved domains elucidating the structural features involved in sugarcane PRS phosphate independence. The recombinant PRS retains secondary structure elements and a quaternary arrangement consistent with known PRS homologues, based on circular dichroism measurements.

Algorithms for Maximum Independent Set in Convex Bipartite Graphs

A bipartite graph G = (V, W, E) is convex if there exists an ordering of the vertices of W such that, for each v. V, the neighbors of v are consecutive in W. We describe both a sequential and a BSP/CGM algorithm to find a maximum independent set in a convex bipartite graph. The sequential algorithm improves over the running time of the previously known algorithm and the BSP/CGM algorithm is a parallel version of the sequential one. The complexity of the algorithms does not depend on |W|.

From the Reliable and Unselfish to the Versatile and Independent : - desired qualities in two Swedish curricula

The process in which girls and boys are constructed and construct themselves to pupils takes place in a context where conceptions of “the good pupil” are distinctly manifested in national school documents. In different types of texts concerning school and education, the image of the pupil that society wants to create emerges. Documents from early childhood education up to university level prioritise qualities such as independence, initiative, accountability and freedom to make ones own choices. Qualities or competencies that are preferred during a certain period change as time passes and society develops. The idea of the democratic subject is not the same today as it was 25 years ago. The purpose of this article is to emphasise and compare different desired qualities described in two Swedish national curricula, competencies that pupils in the compulsory school are supposed to develop. The discussion encompasses the political ideas of the pupil during a period of twenty-five years in light of changes in Western societies during the last decades.

Independent Domain of Symmetric Encryption using Least SignificantBit : Computer Vision, Steganography and Cryptography Techniques

The rapid development of data transfer through internet made it easier to send the data accurate and faster to the destination. There are many transmission media to transfer the data to destination like e-mails; at the same time it is may be easier to modify and misuse the valuable information through hacking. So, in order to transfer the data securely to the destination without any modifications, there are many approaches like cryptography and steganography. This paper deals with the image steganography as well as with the different security issues, general overview of cryptography, steganography and digital watermarking approaches.  The problem of copyright violation of multimedia data has increased due to the enormous growth of computer networks that provides fast and error free transmission of any unauthorized duplicate and possibly manipulated copy of multimedia information. In order to be effective for copyright protection, digital watermark must be robust which are difficult to remove from the object in which they are embedded despite a variety of possible attacks. The message to be send safe and secure, we use watermarking. We use invisible watermarking to embed the message using LSB (Least Significant Bit) steganographic technique. The standard LSB technique embed the message in every pixel, but my contribution for this proposed watermarking, works with the hint for embedding the message only on the image edges alone. If the hacker knows that the system uses LSB technique also, it cannot decrypt correct message. To make my system robust and secure, we added cryptography algorithm as Vigenere square. Whereas the message is transmitted in cipher text and its added advantage to the proposed system. The standard Vigenere square algorithm works with either lower case or upper case. The proposed cryptography algorithm is Vigenere square with extension of numbers also. We can keep the crypto key with combination of characters and numbers. So by using these modifications and updating in this existing algorithm and combination of cryptography and steganography method we develop a secure and strong watermarking method. Performance of this watermarking scheme has been analyzed by evaluating the robustness of the algorithm with PSNR (Peak Signal to Noise Ratio) and MSE (Mean Square Error) against the quality of the image for large amount of data. While coming to see results of the proposed encryption, higher value of 89dB of PSNR with small value of MSE is 0.0017. Then it seems the proposed watermarking system is secure and robust for hiding secure information in any digital system, because this system collect the properties of both steganography and cryptography sciences.

The "reflection protocol" - a way to develop learning and independent thinking?

It is now-a-days more and more common in the academic world to use new forms of “learning-tools”. One of those is the “reflection protocol”, which usually consist of a few pages of freely written text, related to something the students have read. There seems to be a lot of different opinions about the value to use this method. Some teachers and students are enthusiastic and others are rather critical. To write a “reflection protocol” is not in the first place to do a summery, a review, not even to analyze a text. Instead it is about to write down thoughts and questions that comes up as a result of the reading. It is also about doing associations, reflections and to interpret a text and relate this to a theme of some kind. The purpose to use “reflection protocols” is, as we see it, mainly for the student to practice independent thinking from a scientific point of view, but it also gives a possibility to a better understanding of another person’s thinking. This seems to open up for a fruitful dialogue and a way to learn. We will in this paper discuss if that could be the case.

Abstract types and distributions in independent private value auctions

In this note, in an independent private values auction framework, I discuss the relationship between the set of types and the distribution of types. I show that any set of types, finite dimensional or not, can be extended to a larger set of types preserving incentive compatibility constraints, expected revenue and bidder’s expected utilities. Thus for example we may convexify a set of types making our model amenable to the large body of theory in economics and mathematics that relies on convexity assumptions. An interesting application of this extension procedure is to show that although revenue equivalence is not valid in general if the set of types is not convex these mechanism have underlying distinct allocation mechanism in the extension. Thus we recover in these situations the revenue equivalence.

DCE: the dynamic conditional execution in a multipath control independent architecture

This thesis presents DCE, or Dynamic Conditional Execution, as an alternative to reduce the cost of mispredicted branches. The basic idea is to fetch all paths produced by a branch that obey certain restrictions regarding complexity and size. As a result, a smaller number of predictions is performed, and therefore, a lesser number of branches are mispredicted. DCE fetches through selected branches avoiding disruptions in the fetch flow when these branches are fetched. Both paths of selected branches are executed but only the correct path commits. In this thesis we propose an architecture to execute multiple paths of selected branches. Branches are selected based on the size and other conditions. Simple and complex branches can be dynamically predicated without requiring a special instruction set nor special compiler optimizations. Furthermore, a technique to reduce part of the overhead generated by the execution of multiple paths is proposed. The performance achieved reaches levels of up to 12% when comparing a Local predictor used in DCE against a Global predictor used in the reference machine. When both machines use a Local predictor, the speedup is increased by an average of 3-3.5%.