Saffron reduces ATP-induced retinal cytotoxicity by targeting P2X7 receptors

P2X7-type purinergic receptors are distributed throughout the nervous system where they contribute to physiological and pathological functions. In the retina, this receptor is found in both inner and outer cells including microglia modulating signaling and health of retinal cells. It is involved in retinal neurodegenerative disorders such as retinitis pigmentosa and age-related macular degeneration (AMD). Experimental studies demonstrated that saffron protects photoreceptors from light-induced damage preserving both retinal morphology and visual function and improves retinal flicker sensitivity in AMD patients. To evaluate a possible interaction between saffron and P2X7 receptors (P2X7Rs), different cellular models and experimental approaches were used. We found that saffron positively influences the viability of mouse primary retinal cells and photoreceptor-derived 661W cells exposed to ATP, and reduced the ATP-induced intracellular calcium increase in 661W cells. Similar results were obtained on HEK cells transfected with recombinant rat P2X7R but not on cells transfected with rat P2X2R. Finally, patch-clamp experiments showed that saffron inhibited cationic currents in HEK-P2X7R cells. These results point out a novel mechanism through which saffron may exert its protective role in neurodegeneration and support the idea that P2X7-mediated calcium signaling may be a crucial therapeutic target in the treatment of neurodegenerative diseases.     

Plants of the ‘Libellus de Medicinalibus Indorum Herbis’ from Mexico, 1552. Zephyranthes fosteri (Amaryllidaceae) Alkaloids

The Libellus de Medicinalibus Indorum Herbis (Booklet of Indian Medicinal Plants) is the first book of medicinal plants written in the American continent. It was first published in 1939 as ‘An Aztec Herbal’. One of the depicted plants is Huetzcanixochitl (laughing flower) interpreted as Zephyranthes fosteri (Amaryllidaceae). No chemical or pharmacological studies are reported for this species; so, we decide to investigate it. The GC/MS of the bulbs and aerial parts extracts indicated that they contain Amaryllidaceae alkaloids, among them: lycorine, 3-O-acetylpowelline, and norlycoramine. An unknown major alkaloid was isolated and identified by ¹H, ¹³C-NMR and MS, as 3′-demethoxy-6-epimesembranol ( 1 ). The methanolic extract, the alkaloid fraction, and compound 1 inhibited acetylcholinesterase in vitro. Mesembrine alkaloids are found in Sceletium species (Aizoaceae). Several are known as serotonin recapture inhibitors and have been proposed as potential antidepressant drugs. The presence of 1 suggests that Z. fosteri was probably used in pre-Columbian times in Mexico as a ‘stimulant and euphoriant’, alike Sceletium tortuosum by several ethnic groups in South Africa.     

MECP2 Duplication Syndrome: Evidence of Enhanced Oxidative Stress. A Comparison with Rett Syndrome

Rett syndrome (RTT) and MECP2 duplication syndrome (MDS) are neurodevelopmental disorders caused by alterations in the methyl-CpG binding protein 2 (MECP2) gene expression. A relationship between MECP2 loss-of-function mutations and oxidative stress has been previously documented in RTT patients and murine models. To date, no data on oxidative stress have been reported for the MECP2 gain-of-function mutations in patients with MDS. In the present work, the pro-oxidant status and oxidative fatty acid damage in MDS was investigated (subjects n = 6) and compared to RTT (subjects n = 24) and healthy condition (subjects n = 12). Patients with MECP2 gain-of-function mutations showed increased oxidative stress marker levels (plasma non-protein bound iron, intraerythrocyte non-protein bound iron, F₂-isoprostanes, and F₄-neuroprostanes), as compared to healthy controls (P ≤ 0.05). Such increases were similar to those observed in RTT patients except for higher plasma F₂-isoprostanes levels (P < 0.0196). Moreover, plasma levels of F₂-isoprostanes were significantly correlated (P = 0.0098) with the size of the amplified region. The present work shows unique data in patients affected by MDS. For the first time MECP2 gain-of-function mutations are indicated to be linked to an oxidative damage and related clinical symptoms overlapping with those of MECP2 loss-of-function mutations. A finely tuned balance of MECP2 expression appears to be critical to oxidative stress homeostasis, thus shedding light on the relevance of the redox balance in the central nervous system integrity.     

Antimicrobial effect of chlorine on Yersinia enterocolitica

The effects of chlorine at varying pH, culture media and incubation temperatures on one type and two wild type strains of Yersinia enterocolitica were studied. Exposure to 1 and 5 mg 1^-1 did not diminish viability, even after prolonged exposure. A level of 10 mg 1^-1 was required to achieve a 5-log reduction in 120 s for the type strain and 80 s for the wild strains. There was an increase of more than 30% in the rate of disinfection with a 10°C rise, a remarkable increase in antimicrobial activity at pH 5-log reduction in 20 s, as well as marked neutralization of the effect in the presence of 0.1% peptone. Younger cells were more susceptible than older ones, and those from liquid medium more resistant than those from solid medium. Incubation temperature of a 24-h inoculum failed to show any influence. Lastly, there was a noteworthy demand for free chlorine by bacterial biomass, with agreement of the curve depicting the drop in free chlorine in the presence of inoculum with biphasic kinetics of survival curves.     

Obesity and aging affects skeletal muscle renin–angiotensin system and myosin heavy chain proportions in pre-diabetic Zucker rats

Journal of Physiology and Biochemistry - There is a gap in the knowledge regarding regulation of local renin–angiotensin system (RAS) in skeletal muscle during development of obesity and...     

Effect of pH shifts on radiosensitivity of human lymphocytes irradiated in the G2 stage

Experiments were carried out using human lymphocytes in order to test the effect of pH shifts on radiosensitivity of cells irradiated in the G₂ stage. In our culture conditions constant variations in medium pH over the range of 7.4–6.8 were observed as a function of incubation time after PHA stimulation; in addition the pH of the medium was adjusted in parallel cultures over the range of 5.9–8.2. Then we exposed the cultures with different pH to a treatment of X-rays delivered 2 h before fixation.

The pH of the medium was found to greatly affect the yield of induced chromatid aberrations.     

Real-Time Insights into Biological Events: In-Cell Processes and Protein-Ligand Interactions

FlowNMR has the aim of continuously monitoring processes that occur in conditions that are not compatible with being carried out within a closed tube. However, it is sample intensive and not suitable for samples, such as proteins or living cells, that are often available in limited volumes and possibly low concentrations. We here propose a dialysis-based modification of a commercial flowNMR setup that allows for recycling the medium while confining the sample (proteins and cells) within the active volume of the tube. This approach is demonstrated in the specific cases of in-cell NMR and protein-based ligand studies.