Cloning, expression and purification of the general stress protein Yhbo from Escherichia coli.

We cloned, expressed and purified the Escherichia coli yhbO gene product, which is homolog to the Bacillus subtilis general stress protein 18 (the yfkM gene product), the Pyrococcus furiosus intracellular protease PfpI, and the human Parkinson disease protein DJ-1. The gene coding for YhbO was generated by amplifying the yhbO gene from E. coli by polymerase chain reaction. It was inserted in the expression plasmid pET-21a, under the transcriptional control of the bacteriophage T7 promoter and lac operator. A BL21(DE3) E. coli strain transformed with the YhbO-expression vector pET-21a-yhbO, accumulates large amounts of a soluble protein of 20 kDa in SDS-PAGE that matches the expected YhbO molecular weight. YhbO was purified to homogeneity by HPLC DEAE ion exchange chromatography and hydroxylapatite chromatography and its identity was confirmed by N-terminal sequencing and mass spectrometry analysis. The native protein exists in monomeric, trimeric and hexameric forms

The Escherichia coli thioredoxin homolog YbbN/Trxsc is a chaperone and a weak protein oxidoreductase.

Escherichia coli contains two thioredoxins, Trx1 and Trx2, and a thioredoxin-like protein, YbbN, which presents a strong homology in its N-terminal part with thioredoxin 1 and 2. YbbN, however, does not possess the canonical Cys-x-x-Cys active site of thioredoxins, but instead a Ser-x-x-Cys site. In addition to Cys-38, located in the SxxC site, it contains a second cysteine, Cys-63, close to Cys-38 in the 3D model. Cys-38 and Cys-63 undergo an oxidoreduction process, suggesting that YbbN functions with two redox cysteines. Accordingly, YbbN catalyzes the oxidation of reduced RNase and the isomerization of scrambled RNase. Moreover, upon oxidation, its oligomeric state changes from dimers to tetramers and higher oligomers. YbbN also possesses chaperone properties, promoting protein folding after urea denaturation and forming complexes with unfolded proteins. This is the first biochemical characterization of a member of the YbbN class of bacterial thioredoxin-like proteins, and in vivo experiments will allow to determine the importance of its redox and chaperone properties in the cellular physiology

Tumorigenic proteins upregulated in the MYCN-amplified IMR-32 human neuroblastoma cells promote proliferation and migration.

Childhood neuroblastoma is one of the most common types of extra-cranial cancer affecting children with a clinical spectrum ranging from spontaneous regression to malignant and fatal progression. In order to improve the clinical outcomes of children with high-risk neuroblastoma, it is crucial to understand the tumorigenic mechanisms that govern its malignant behaviors. MYCN proto-oncogene, bHLH transcription factor (MYCN) amplification has been implicated in the malignant, treatment-evasive nature of aggressive, high-risk neuroblastoma. In this study, we used a SILAC approach to compare the proteomic signatures of MYCN-amplified IMR-32 and non-MYCN-amplified SK-N-SH human neuroblastoma cells. Tumorigenic proteins, including fatty-acid binding protein 5 (FABP5), L1-cell adhesion molecule (L1-CAM), baculoviral IAP repeat containing 5 [BIRC5 (survivin)] and high mobility group protein A1 (HMGA1) were found to be significantly upregulated in the IMR-32 compared to the SK-N-SH cells and mapped to highly tumorigenic pathways including, MYC, MYCN, microtubule associated protein Tau (MAPT), E2F transcription factor 1 (E2F1), sterol regulatory element binding transcription factor 1 or 2 (SREBF1/2), hypoxia-inducible factor 1α (HIF-1α), Sp1 transcription factor (SP1) and amyloid precursor protein (APP). The transcriptional knockdown (KD) of MYCN, HMGA1, FABP5 and L1-CAM significantly abrogated the proliferation of the IMR-32 cells at 48 h post transfection. The early apoptotic rates were significantly higher in the IMR-32 cells in which FABP5 and MYCN were knocked down, whereas cellular migration was significantly abrogated with FABP5 and HMGA1 KD compared to the controls. Of note, L1-CAM, HMGA1 and FABP5 KD concomitantly downregulated MYCN protein expression and MYCN KD concomitantly downregulated L1-CAM, HMGA1 and FABP5 protein expression, while survivin protein expression was significantly downregulated by MYCN, HMGA1 and FABP5 KD. In addition, combined L1-CAM and FABP5 KD led to the concomitant downregulation of HMGA1 protein expression. On the whole, our data indicate that this inter-play between MYCN and the highly tumorigenic proteins which are upregulated in the malignant IMR-32 cells may be fueling their aggressive behavior, thereby signifying the importance of combination, multi-modality targeted therapy to eradicate this deadly childhood cancer

Association of hypertension with coronary artery disease onset in the Lebanese population

The onset of coronary artery disease (CAD) is influenced by cardiovascular risk factors that often occur in clusters and may build on one another. The objective of this study is to examine the relationship between hypertension and CAD age of onset in the Lebanese population. This retrospective analysis was performed on data extracted from Lebanese patients (n = 3,753). Logistic regression examined the association of hypertension with the age at CAD diagnosis after controlling for other traditional risk factors. The effect of antihypertensive drugs and lifestyle changes on the onset of CAD was also investigated. Results showed that hypertension is associated with late onset CAD (OR=0.656, 95% CI=0.504-0.853, p=0.001). Use of antihypertensive drugs showed a similar association with delayed CAD onset. When comparing age of onset in CAD patients with traditional risk factors such as hypertension, diabetes, hyperlipidemia, obesity, smoking and family history of CAD, the age of onset was significantly higher for patients with hypertension compared to those with any of the other risk factors studied (p < 0.001). In conclusion, hypertension and its treatment are associated with late coronary atherosclerotic manifestations in Lebanese population. This observation is currently under investigation to clarify its genetic and/or environmental mechanisms

Modelling the regulation of telomere length: the effects of telomerase and G-quadruplex stabilising drugs

Telomeres are guanine-rich sequences at the end of chromosomes which shorten during each replication event and trigger cell cycle arrest and/or controlled death (apoptosis) when reaching a threshold length. The enzyme telomerase replenishes the ends of telomeres and thus prolongs the life span of cells, but also causes cellular immortalisation in human cancer. G-quadruplex (G4) stabilising drugs are a potential anticancer treatment which work by changing the molecular structure of telomeres to inhibit the activity of telomerase. We investigate the dynamics of telomere length in different conformational states, namely t-loops, G-quadruplex structures and those being elongated by telomerase. By formulating deterministic differential equation models we study the effects of various levels of both telomerase and concentrations of a G4-stabilising drug on the distribution of telomere lengths, and analyse how these effects evolve over large numbers of cell generations. As well as calculating numerical solutions, we use quasicontinuum methods to approximate the behaviour of the system over time, and predict the shape of the telomere length distribution. We find those telomerase and G4-concentrations where telomere length maintenance is successfully regulated. Excessively high levels of telomerase lead to continuous telomere lengthening, whereas large concentrations of the drug lead to progressive telomere erosion. Furthermore, our models predict a positively skewed distribution of telomere lengths, that is, telomeres accumulate over lengths shorter than the mean telomere length at equilibrium. Our model results for telomere length distributions of telomerase-positive cells in drug-free assays are in good agreement with the limited amount of experimental data available

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Fault Tolerance Technique Using Bidirectional Hetero-Associative Memory for Self-Reconfigurable Programmable Matter

International audienceProgrammable Matter (PM) based on modular robots is a material which can be reprogrammed to have different shapes and to change its physical properties on demand. It can be deployed in several domains and has a variety of applications in construction, surgery, environmental science, space exploration, etc. PM is composed of a big number of limited resources connected robots called modules or particles to form its shape. These modules communicate with each other and move around each other dynamically in order to switch from one configuration to another. Due to the limited resources of modules and the high number of packets that transit within the system, it is very challenging to ensure packet delivery with high reliability. In this paper, we are using a Bidirectional Hetero-Associative Memory (BHAM) networks to improve the reliability and fault tolerance in PM. The idea is to let modules sending packets with smaller size without loosing any information. Furthermore, this model is also capable to remove noise from received packets. The proposed approach is tested on a real programmable matter blinky blocks platform as well as via simulations. We studied two versions of artificial neural networks based on storage capacity. The experimental results show that the studied approach is efficient in reducing the size of packets that transit in the system thus reducing energy consumption and it is capable to detect and remove noise and correct noisy packets

Escherichia coli facing stresses (role of chaperones and proteases)

De nombreuses maladies sont dues à des défauts de repliement ou de solubilité des protéines. La base de ces pathologies est liée à la formation d'agrégats toxiques de protéines, et à l'incapacité des cellules à les dégrader. Notre travail porte sur la solubilisation des protéines, avec intervention de protéines chaperons et de protéases spécifiques. Nous nous intéressons en particulier aux stress thermique et acide, et à la correction des problèmes d'agrégation de protéines qui en résultent. Après avoir caractérisé ses propriétés chaperons, nous avons démontré que la protéine Hsp31 est très efficace dans la solubilisation des peptides. Elle possède une activité aminopeptidase spécifique des peptides ayant une alanine ou un acide aminé basique en N-terminal. Une accumulation de peptides dans les cellules déficientes en Hsp31 suggère un rôle physiologique particulier lié à la fonction de chaperon à peptides. La protéine YhbO a des homologues dans presque tous les organismes. Cette conservation indiquerait un rôle particulièrement important dans la physiologie cellulaire. Nous avons démontré une létalité élevée des mutants déficients en YhbO confrontés à différents stress, ce qui suggère qu'YhbO est un élément important dans la protection des cellules contre une multitude de stress environnementaux. Nous avons caractérisé la protéine HdeB comme un nouveau chaperon de stress acide. Cette protéine, présente dans le périplasme, est codée par l'opéron hdeAB, HdeA étant aussi un chaperon de stress acide. Ces deux chaperons permettent de solubiliser les protéines aux pH acides et empêcher ainsi l'agrégation des protéines périplasmiques à des pH légèrement ou fortement acides.PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Les Femmes islamistes de Hamas : entre le Féminisme et le Nationalisme

In December, 1995,when Hamas announced the establishment of the Islamic National Salvation Party, a political organisation separate from its military wing, it opened the way for involvement of the Islamic movement in the political processes brought about in the West Bank and Gaza with the signing of the Oslo Accords and the arrival of the Palestinian National Authority. In speaking of the rights of different groups, including women, in its founding statement, and in setting up in Gaza a Women’s Action Department, the new Party opened its doors to the ‘new Islamic woman’ and to a significant evolution in Islamist gender ideology in Gaza, if not in the West Bank -- where, due to Hamas’ policy there of targeting only males, there exists no parallel to the Salvation Party or organisational support for women like that represented by the Women’s Action Department in Gaza. Hamas’ gender ideology, like that of the secularist parties, remains contradictory, and doors to women’s equality only partly open ; nevertheless, Islamist women have managed to build impressive, well-organised women’s constituencies among highly educated and professional women coming from poor and refugee backgrounds ; and the Salvation Party shows an increasing tendency to foster gender equality and more egalitarian social ideals, while holding fast to the agenda of national liberation. These advances have been achieved both through alternative interpretations of Islamic legal and religious texts, and through positive engagement with the discourses of other groups, whether secular feminists or nationalists. In contrast, secularists are losing ground by advocating a discourse of rights in isolation from the national agenda and in the absence of a mobilising organisation. These developments suggest possibilities for mutual accommodation between Islamist and other Palestinian groups. They suggest also that the nature of the state proposed by Islamists will depend to a large extent on the visions and challenges posed by other nationalist and secularist groups

RePoSt: Distributed Self-Reconfiguration Algorithm for Modular Robots Based on Porous Structure

International audienceIn this paper, we propose a new self-reconfiguration scheme for modular robots based on a metamodule design that allows to form a 3D porous structure. The porous structure enables a parallel flow of modules inside it without blocking. The metamodule can also be used to fill its internal volume with an additional number of modules allowing the structure to be compressible and expandable. Hence, it is a potential for improving the self-reconfiguration process. We first present the metamodule model and the porous structure built using it. Then, we describe an algorithm to self-reconfigure the structure from an initial shape to a given goal shape. We evaluated the algorithm in simulation on structures composed of up to 2,700 modules. We studied the performance in term of parallelism, showed that the number of communications is proportional to the number of motions and the execution time varies linearly with the diameter of the configuration