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The DNA-glycosylase OGG1 oversees the detection and clearance of the 7,8-dihydro-8-oxoguanine (8-oxoG), which is the most frequent form of oxidized base in the genome. This lesion is deeply buried within the double-helix and its detection requires careful inspection of the bases by OGG1 via a mechanism that remains only partially understood. By analyzing OGG1 dynamics in the nucleus of living human cells, we demonstrate that the glycosylase constantly samples the DNA by rapidly alternating between diffusion within the nucleoplasm and short transits on the DNA. This sampling process, that we find to be tightly regulated by the conserved residue G245, is crucial for the rapid recruitment of OGG1 at oxidative lesions induced by laser micro-irradiation. Furthermore, we show that residues Y203, N149 and N150, while being all involved in early stages of 8-oxoG probing by OGG1 based on previous structural data, differentially regulate the sampling of the DNA and recruitment to oxidative lesions., (© The Author(s) 2023. Published by Oxford University Press on behalf of Nucleic Acids Research.)

One of the most abundant DNA lesions induced by oxidative stress is the highly mutagenic 8-oxoguanine (8-oxoG), which is specifically recognized by 8-oxoguanine DNA glycosylase 1 (OGG1) to initiate its repair. How DNA glycosylases find small non-helix-distorting DNA lesions amongst millions of bases packaged in the chromatin-based architecture of the genome remains an open question. Here, we used a high-throughput siRNA screening to identify factors involved in the recognition of 8-oxoG by OGG1. We show that cohesin and mediator subunits are required for re-localization of OGG1 and other base excision repair factors to chromatin upon oxidative stress. The association of OGG1 with euchromatin is necessary for the removal of 8-oxoG. Mediator subunits CDK8 and MED12 bind to chromatin and interact with OGG1 in response to oxidative stress, suggesting they participate in the recruitment of the DNA glycosylase. The oxidative stress-induced association between the cohesin and mediator complexes and OGG1 reveals an unsuspected function of those complexes in the maintenance of genomic stability., (© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.)

A visible astrocomb spanning 555-890 nm has been implemented on the 10-m Southern African Large Telescope, delivering complete calibration of one channel of its high-resolution spectrograph and an accurate determination of its resolving power. A novel co-coupling method allowed simultaneous observation of on-sky, Th-Ar lamp and astrocomb channels, reducing the wavelength calibration uncertainty by a factor of two compared to that obtained using only Th-Ar lines. The excellent passive stability of the master frequency comb laser enabled broadband astrocomb generation without the need for carrier-envelope offset frequency locking, and an atomically referenced narrow linewidth diode laser provided an absolute fiducial marker for wavelength calibration. The simple astrocomb architecture enabled routine operation by non-specialists in an actual telescope environment. On-sky spectroscopy results are presented with direct calibration achieved entirely using the astrocomb.

Multi-layered silica and titania thin films were prepared via an aqueous sol-gel route. The titania layers could efficiently entrap anti-HRP antibodies and showed increase in stability upon ageing, up to 2 months. Specific activity of the entrapped antibodies could be monitored in a reliable manner over one week. The silica films showed lower performances, as a probable consequence of large pore size. Increase in the titania precursor (TiBALDH) concentration and addition of glycerol allowed the design of tri-enzymatic multi-layered systems for the detection of lactose. The multilayer approach showed higher robustness than the co-immobilization of the enzymes in a single layer. This process is simple, solvent-free and flexible, opening the route to multi-biofunctional materials at the nanoscale.

Secreted proteins play a key role in cell signaling and communication. We recently showed that ionizing radiations induced a delayed cell death of breast cancer cells, mediated by the death receptor pathways through the expression of soluble forms of "death ligands." Using the same cell model, the objective of our work was the identification of diffusible factors, secreted following cell irradiation, potentially involved in cell death signaling. Differential proteomic analysis of conditioned media using 2DE resulted in detection of numerous spots that were significantly modulated following cell irradiation. The corresponding proteins were identified using MALDI-TOF MS and LC-MS/MS approaches. Interestingly, five isoforms of cyclophilin A were observed as increased in conditioned medium of irradiated cells. These isoforms differed in isoelectric points and in accumulation levels. An increase of cyclophilin A secretion was confirmed by Western blotting of conditioned media of irradiated or radiosentive mammary cells. These isoforms displayed an interesting pattern of protein maturation and post-translational modifications, including an alternating removal of N-terminal methionine, associated with a combination of acetylations and methylations. The role of the protein is discussed in relation with its potential involvement in the mechanisms of intercells relationships and radiosensitivity., (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The kinetics and thermodynamics of the thermal inactivation of polyphenol oxidase (PPO) in an aqueous extract from mushroom Agaricus bisporus (J.E. Lange) Imbach was studied, using pyrocatechol as a substrate. Optimal conditions for enzymatic studies were determined to be pH 7.0 and 35-40 °C. The kinetics of PPO-catalyzed oxidation of pyrocatechol followed the Haldane model with an optimum substrate concentration of 20 mM. Thermal inactivation of PPO was examined in more detail between 50 and 73 °C and in relation to exposure time. Obtained monophasic kinetics were adequately described by a first-order model, with significant inactivation occurring with increasing temperature (less than 10% preserved activity after 6 min at 65 °C). Arrhenius plot determination and calculated thermodynamic parameters suggest that the PPO in aqueous extract from Agaricus bisporus mushroom is a structurally robust yet temperature-sensitive biocatalyst whose inactivation process is mainly entropy-driven.

Objective: Genesis of sleep apnoea syndrome (SAS) in chronic heart failure (CHF) is not well known. The aim of our study was to find associated factors to SAS in heart failure (HF) and to look for differences between central sleep apnea (CSA) and obstructive sleep apnea (OSA)., Patients and Methods: We realised a cross-sectional and retrospective study. Thirty patients with stable heart failure under medical optimal therapy were included. Polygraphy, echocardiography and cardiopulmonary exercise were systematically performed., Results: Men were predominant (80%) in the group. Mean age, left ventricular ejection fraction (LVEF) were respectively 64.1±13.8years and 40±9.8%. SAS was present in 60% of patients (33.3% were classified as central sleep apnoea [CSA] and 26.7% as obstructive sleep apnoea [OSA]). Body mass index, blood pressure and left ventricular pressures estimated by the E/Ea ratio were significantly higher in the group with SAS (P<0.05) compared to the non SAS group. New York Heart Association class was significantly higher (P=0.04) and the predicted peak VO(2) was significantly lower in CSA patients compared to OSA patients., Conclusion: High left ventricular pressures estimated by the E/Ea are significantly associated with SAS in heart failure. CSA patients tend to have a worse functional state than OSA patients., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Inorganic gels formed using the sol-gel process are promising hosts for the encapsulation of living organisms and the design of cell-based biosensors. However, the possibility to use the biological activity of entrapped cells as a biological signal requires a good understanding and careful control of the chemical and physical conditions in which the organisms are placed before, during, and after gel formation, and their impact on cell viability. Moreover, it is important to examine the possible transduction methods that are compatible with sol-gel encapsulated cells. Through an updated presentation of the current knowledge in this field and based on selected examples, this review shows how it has been possible to convert a chemical technology initially developed for the glass industry into a biotechnological tool, with current limitations and promising specificities.

Introduction: We report a case of constrictive péricarditis initially revealed by a massive left sided pleural effusion., Case Report: The patient was dyspnoeic without any associated clinical signs. Only cardiac catheterization gave the diagnosis with a characteristic dip-plateau of the right ventricle. After full assessment, no aetiology was found., Conclusion: After a treatment with corticosteroids, the progress has been favourable to date.

Introduction: We report the case of a patient suffering from disseminated actinomycosis., Case Report: A fifty-two year old man, who was both a heavy smoker and an alcoholic, was admitted to hospital with confusion associated with a pseudo-tumoral right upper lobe pneumonia. Brain computed tomography was normal on the day of admission but when repeated fifteen days later four lesions were seen with appearances suspicious of metastatic malignant disease. The isolation of Actinomyces odontolyticus in the bronchoalveolar lavage culture and the absence of evidence for neoplastic disease despite extensive investigation led to a diagnosis of disseminated actinomycosis with pulmonary and cerebral involvement. The patient's clinical condition improved with antibiotic therapy. The disseminated form of this infection as well as presentation with multifocal brain abscesses is rare., Conclusion: The diagnosis of actinomycosis is problematic because it is an uncommon infection and microbiological identification is often difficult and delayed. It should be considered when clinical presentation suggests malignant disease but there is no histological confirmation.

Viral or fungal pneumonia generally occurs in immunocompromised patients. We report a case of hypoxic pneumonia unresponsive to broad-spectrum antibiotic therapy in a patient whose only risk factor for immunodeficiency was mild silent renal failure. The causal association between Herpes simplex and Geotrichum candidum was retained on the basis of endobronchial samples and the favorable course after institution of specific treatment. It is thus useful to consider these pathogens in patients with lung infection in order to institute specific treatment.

We report a case of interstitial pneumonia found by a woman who suffered from a gastroesophageal reflux unamenable to usual treatments. The HR-tomographic discovery of a tone esophagus lead to a manometric study. The association of high autoantibodies levels and radiographic and manometric data were characteristic of esophageal and pulmonary scleroderma.

Inhaled nitric oxide (NO) may be beneficial in patients with acute respiratory distress syndrome (ARDS). The effects of inhaled NO on intracranial pressure have not yet been assessed. This case shows the beneficial effects of inhaled NO in a patient with ARDS and intracranial hypertension.