Glutathione-Induced Calcium Shifts in Chick Retinal Glial Cells

Neuroglia interactions are essential for the nervous system and in the retina Müller cells interact with most of the neurons in a symbiotic manner. Glutathione (GSH) is a low-molecular weight compound that undertakes major antioxidant roles in neurons and glia, however, whether this compound could act as a signaling molecule in neurons and/or glia is currently unknown. Here we used embryonic avian retina to obtain mixed retinal cells or purified Müller glia cells in culture to evaluate calcium shifts induced by GSH. A dose response curve (0.1–10mM) showed that 5–10mM GSH, induced calcium shifts exclusively in glial cells (later labeled and identified as 2M6 positive cells), while neurons responded to 50mM KCl (labeled as β_III tubulin positive cells). BBG 100nM, a P2X7 blocker, inhibited the effects of GSH on Müller glia. However, addition of DNQX 70μM and MK-801 20μM, non-NMDA and NMDA blockers, had no effect on GSH calcium induced shift. Oxidized glutathione (GSSG) at 5mM failed to induce calcium mobilization in glia cells, indicating that the antioxidant and/or structural features of GSH are essential to promote elevations in cytoplasmic calcium levels. Indeed, a short GSH pulse (60s) protects Müller glia from oxidative damage after 30 min of incubation with 0.1% H₂O₂. Finally, GSH induced GABA release from chick embryonic retina, mixed neuron-glia or from Müller cell cultures, which were inhibited by BBG or in the absence of sodium. GSH also induced propidium iodide uptake in Müller cells in culture in a P2X7 receptor dependent manner. Our data suggest that GSH, in addition to antioxidant effects, could act signaling calcium shifts at the millimolar range particularly in Müller glia, and could regulate the release of GABA, with additional protective effects on retinal neuron-glial circuit.     

Effect of Different Doses of Estrogen on the Nigrostriatal Dopaminergic System in Two 6-Hydroxydopamine-Induced Lesion Models of Parkinson’s Disease

Parkinson’s disease results from a degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNpc) and it is more prevalent in men than in women. Estrogen has neuroprotective action of the nigrostriatal dopaminergic (NSDA) neurons. It was investigated whether differences in plasma 17β-estradiol (E2) levels alter the degree of neuroprotection in NSDA neurons. Ovariectomized rats, implanted with subcutaneous capsules containing 400, 800 or 1,600 μg of E2 or corn oil, were injected with 1 μg of 6-OHDA in the SNpc or the medial forebrain bundle (MFB). Striatal dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and plasma E2 levels were measured. Only at 400 μg, E2 protected striatal DA against lesion of the MFB. In the SNpc, E2 failed to prevent DA depletion, but increased DOPAC/DA ratio in the striatum. In an NSDA moderate lesion, E2 has a neuroprotective action. In a severe lesion, E2 could stimulate DA activity in remaining neurons.     

HAA1 and PRS3 overexpression boosts yeast tolerance towards acetic acid improving xylose or glucose consumption: unravelling the underlying mechanisms

Applied Microbiology and Biotechnology - Acetic acid tolerance and xylose consumption are desirable traits for yeast strains used in industrial biotechnological processes. In this work,...     

Softwood biodegradation by an ascomycete Chrysonilia sitophila (TFB 27441 strain)

Biodegradation of softwood ( Pinus radiata ) by the ascomycete Chrysonilia sitophila was dependent on the nitrogen and glucose concentrations in the culture medium. Optimization studies of the delignification process, in which the nitrogen (0–50mmol/l NH⁺₄) and glucose (0–2%) concentrations were varied, showed a maximal value of 17·8% for sawdust degradation in cultures containing 10 mmol/l NH₄⁺and 1·0% glucose. Solubility of the decayed sawdust in 1% NaOH at maximal delignification conditions showed a threefold increase and changes in the thermogravimetric pattern were also observed. Biodegraded wood chips showed significant decreases of the 280 and 310 nm characteristic lignin bands in the u.v. reflectance spectra.     

Performance of 3 methods for quality control for gynecologic cytology diagnoses

OBJECTIVE: To evaluate performance and viability of internal quality control (QC) strategies in a public health laboratory of the state of S?o Paulo. STUDY DESIGN: A retrospective study was performed with 3 QC strategies to improve internal cytologic diagnoses: morphologic guided-list criteria (MGLC), 100% rapid-rescreening (100% RR) of negative slides ("turret" method) and 10% rescreening (10% R) of negative slides. Cases were examined at Adolfo Lutz Institute, S?o Paulo, Brazil, from 2002 to 2004. Histopathologic results, when available, were considered gold standard; cytologic consensus diagnosis was by 2 pathologists when histologic results were unavailable. RESULTS: MGLC selected 20.7% samples with cytologic atypias, 10% R selected 0.6% and RR selected 2.5%. Cytologic/histologic initial concordance was 57.4%, low-grade squamous intra-epithelial lesion false negative rate was 34.9% and high-grade squamous intraepithelial lesion false negative rate was 12.2%. After diagnosis, consensus concordance was 97.2%. CONCLUSION: The 100% RR and 10% R QC strategies detected more false negative cases in liquid-based cytology than in conventional Pap smears. The 100% RR strategy reduced the false negative results and allowed evaluation of individual staff performance. The 10% R strategy did not offer significant results. We concluded that association of MGLC and 100% RR strategies might improve cytologic diagnostic quality.     

Screening for antiproliferative activity of six southern Brazilian species of Hypericum

The crude methanolic extracts of six species of Hypericum growing in southern Brazil (Hypericum caprifoliatum Cham. & Schlecht., H. carinatum Griseb., H. connatum Lam., H. myrianthum Cham. & Schlecht., H. polyanthemum Klotzsch ex Reichardt and H. ternum A. St. Hil.) were screened for their antiproliferative activity against two cell lines (HT-29 human colon carcinoma cells and H-460 non-small cell lung carcinoma). The most active crude extracts were those from H. caprifoliatum, H. myrianthum and, to a lesser extent, from H. connatum. All plants were submitted to fractionation with solvents in increasing polarity and re-assayed for the two cell lines used previously, as well as U-373 human malignant glioma cells. The most active fractions were the hexane fractions obtained from H. caprifoliatum, H. myrianthum and H. ternum.     

Diptera Brachycera found inside the esophagus of a mummified adult male from the early XIX century, Lisbon, Portugal

Fly puparia and adult fragments of diptera muscid were found inside the esophagus of a mummified body from the early XIX century, buried inside the crypt of the Sacrament Church (Lisbon, Portugal). The identification of the material revealed a monospecific colonization by Ophyra capensis (Wiedemann) (Diptera: Muscidae), a species known to invade corpses in the ammoniacal fermentation wave. This species can be found in corpses kept indoors, not available to the early waves of blowflies (Diptera: Calliphoridae). In the present case, the number of pupae and their developmental stage suggest that the female invaded the mummified corpse through the partially opened mouth and the oviposition took place directly inside the esophagus. This is the first case of O. capensis infesting internal organs of an intact corpse. The use of chemical products for the embalming process probably explains why external colonization did not occur.     

Cloning and deletion mutagenesis using direct protein-protein interaction on an expression vector. Identification of the calmodulin binding domain of alpha-fodrin

We have screened a lambda gt11 library, constructed with mouse macrophage cDNA, in order to isolate clones that code for calmodulin binding proteins. We have developed a new approach for this purpose using radioactive calmodulin (produced by genetic engineering) to detect fusion proteins that interact with this protein with high affinity. A cDNA clone that codes for mouse macrophage fodrin was isolated, sequenced and identified. By deleting part of the sequence the calmodulin binding domain was located on the fodrin sequence. The site is situated on repeat 11 of fodrin and probably on the extra arm of this repeat. The method we developed is widely applicable to site-directed mutagenesis of interacting proteins.