Oxidative inactivation of NiFeSe hydrogenase

International audienceWe propose a resolution to the paradox that spectroscopic studies of NiFeSe hydrogenase have not revealed any major signal attributable to NiIII states formed upon reaction with O2, despite the fact that two inactive states are formed upon either aerobic or anaerobic oxidation

Functional Role of P-Glycoprotein and Binding Protein Effect on the Placental Transfer of Lopinavir/Ritonavir in the Ex Vivo Human Perfusion Model

Aims. To study the influence of P-glycoprotein (P-glycoprotein, ABCB1, MDR1) function on placental transfer of lopinavir with ritonavir at different albumin concentrations. Methods. Cotyledons were perfused with lopinavir, ritonavir, and the internal control antipyrin, at various albumin concentrations (10, 30, 40 g/L). After the control phase of each experiment, the P-glycoprotein inhibitor ciclosporin A was added at middle perfusion (45 minutes). Fetal Transfer Rate (FTR) and Clearance Index (CLI) were compared between the 2 phases. Results. In the control phase, the clearance index of lopinavir decreased from 0.401 ± 0.058 to 0.007 ± 0.027, as albumin concentrations increased from 10 g/L to higher concentrations (30, 40 g/L). When adding ciclosporin A at physiological albumin concentrations, the clearance index of lopinavir increased significantly 10.3 fold (95% of CI difference [−0.156, −0.002], P = .046) and became positive for ritonavir. Conclusions. Even at high albumin concentrations, inhibition of placental P-glycoprotein increased placental transfer of lopinavir, suggesting that this efflux pump actively reduces placental transfer of the drug. This mechanism may play a role in fetal exposure to maternal antiretroviral therapy

The Israeli strain IS-98-ST1 of West Nile virus as viral model for West Nile encephalitis in the Old World

West Nile virus (WNV) recently became a major public health concern in North America, the Middle East, and Europe. In contrast with the investigations of the North-American isolates, the neurovirulence properties of Middle-Eastern strains of WNV have not been extensively characterized. Israeli WNV strain IS-98-ST1 that has been isolated from a white stork in 1998, was found to be highly neuroinvasive in adult C57BL/6 mice. Strain IS-98-ST1 infects primary neuronal cells from mouse cortex, causing neuronal death. These results demonstrate that Israeli strain IS-98-ST1 provides a suitable viral model for WNV-induced disease associated with recent WNV outbreaks in the Old World

Impact of lifestyle and diet on endometriosis: a fresh look to a busy corner

Endometriosis is a chronic inflammatory disorder with a prevalence of six to ten percent in women of childbearing age. As long as the aetiology of endometriosis is not fully understood and the disease has no definitive treatment, an examination of the environmental factors or interventions that could modify or cure endometriosis would greatly benefit women suffering from this chronic condition. This literature review utilized the electronic databases PubMed, EMBASE, and MEDLINE until February 2021. Studies indicate that fish oil may have a positive effect on reducing endometriosis-related pain due to the effects of pro-inflammatory prostaglandins derived from omega-3 fatty acids. The same effect was seen with the introduction of antioxidant vitamins C, D, and E. There is clinical viability of a low fermentable oligo-, di-, and monosaccharides and polyols diet to successfully reduce the symptoms of patients who suffer from both endometriosis and irritable bowel syndrome. Despite the low level of evidence, there are frequent associations between endometriosis and gastrointestinal conditions in addition to the influence of various nutritional factors on the disease. The management of endometriosis requires a holistic approach focused on reducing overall inflammation, increasing detoxification, and attenuating troublesome symptoms. A dietician may provide great benefit in the management of these patients, especially at younger ages and in early stages. High-level evidence and welldesigned randomized studies are lacking when it comes to studying the effect of lifestyle and dietary intake on endometriosis. Inarguably, further research with a more extensive focus is needed

Stability of the H-cluster under whole-cell conditions-formation of an Htrans-like state and its reactivity towards oxygen.

Hydrogenases are metalloenzymes that catalyze the reversible oxidation of molecular hydrogen into protons and electrons. For this purpose, [FeFe]-hydrogenases utilize a hexanuclear iron cofactor, the H-cluster. This biologically unique cofactor provides the enzyme with outstanding catalytic activities, but it is also highly oxygen sensitive. Under in vitro conditions, oxygen stable forms of the H-cluster denoted Htrans and Hinact can be generated via treatment with sulfide under oxidizing conditions. Herein, we show that an Htrans-like species forms spontaneously under intracellular conditions on a time scale of hours, concurrent with the cells ceasing H2 production. Addition of cysteine or sulfide during the maturation promotes the formation of this H-cluster state. Moreover, it is found that formation of the observed Htrans-like species is influenced by both steric factors and proton transfer, underscoring the importance of outer coordination sphere effects on H-cluster reactivity

Characterization of Reemerging Chikungunya Virus

An unprecedented epidemic of chikungunya virus (CHIKV) infection recently started in countries of the Indian Ocean area, causing an acute and painful syndrome with strong fever, asthenia, skin rash, polyarthritis, and lethal cases of encephalitis. The basis for chikungunya disease and the tropism of CHIKV remain unknown. Here, we describe the replication characteristics of recent clinical CHIKV strains. Human epithelial and endothelial cells, primary fibroblasts and, to a lesser extent, monocyte-derived macrophages, were susceptible to infection and allowed viral production. In contrast, CHIKV did not replicate in lymphoid and monocytoid cell lines, primary lymphocytes and monocytes, or monocyte-derived dendritic cells. CHIKV replication was cytopathic and associated with an induction of apoptosis in infected cells. Chloroquine, bafilomycin-A1, and short hairpin RNAs against dynamin-2 inhibited viral production, indicating that viral entry occurs through pH-dependent endocytosis. CHIKV was highly sensitive to the antiviral activity of type I and II interferons. These results provide a general insight into the interaction between CHIKV and its mammalian host