Integrated socio-hydrogeological approach to tackle nitrate contamination in groundwater resources. The case of Grombalia Basin (Tunisia).

Nitrate contamination still remains one of the main groundwater quality issues in several aquifers worldwide, despite the perduring efforts of the international scientific community to effectively tackle this problem. The classical hydrogeological and isotopic investigations are obviously of paramount importance for the characterization of contaminant sources, but are clearly not sufficient for the correct and long-term protection of groundwater resources. This paper aims at demonstrating the effectiveness of the socio-hydrogeological approach as the best tool to tackle groundwater quality issues, while contributing bridging the gap between science and society. An integrated survey, including land use, hydrochemical (physicochemical parameters and major ions) and isotopic (δ15NNO3 and δ18ONO3) analyses, coupled to capacity building and participatory activities was carried out to correctly attribute the nitrate origin in groundwater from the Grombalia Basin (North Tunisia), a region where only synthetic fertilizers have been generally identified as the main source of such pollution. Results demonstrates that the basin is characterized by high nitrate concentrations, often exceeding the statutory limits for drinking water, in both the shallow and deep aquifers, whereas sources are associated to both agricultural and urban activities. The public participation of local actors proved to be a fundamental element for the development of the hydrogeological investigation, as it permitted to obtain relevant information to support data interpretation, and eventually guaranteed the correct assessment of contaminant sources in the studied area. In addition, such activity, if adequately transferred to regulators, will ensure the effective adoption of management practices based on the research outcomes and tailored on the real needs of the local population, proving the added value to include it in any integrated investigation.

Sialidase NEU4 is involved in glioblastoma stem cell survival.

The human sialidase, NEU4, has emerged as a possible regulator of neuronal differentiation and its overexpression has been demonstrated to promote the acquisition of a stem cell-like phenotype in neuroblastoma cells. In this paper, we demonstrated that glioblastoma stem cells (GSCs) isolated from glioblastoma multiforme (GBM) cell lines and patients' specimens as neurospheres are specifically marked by the upregulation of NEU4; in contrast, the expression of NEU4 is very low in non-neurosphere-differentiated GBM cells. We showed that NEU4 silencing by miRNA or a chemical inhibitor of its catalytic activity triggered key events in GSCs, including (a) the activation of the glycogen synthase kinase 3ß, with the consequent inhibition of Sonic Hedgehog and Wnt/ß-catenin signalling pathways; (b) the decrease of the stem cell-like gene expression and marker signatures, evidenced by the reduction of NANOG, OCT-4, SOX-2, CD133 expression, ganglioside GD3 synthesis, and an altered protein glycosylation profile; and (c) a significant decrease in GSCs survival. Consistent with this finding, increased NEU4 activity and expression induced in the more differentiated GBM cells by the NEU4 agonist thymoquinone increased the expression of OCT-4 and GLI-1. Thus, NEU4 expression and activity appeared to help to determine the molecular signature of GSCs and to be closely connected with their survival properties. Given the pivotal role played by GSCs in GBM lethality, our results strongly suggest that NEU4 inhibition could significantly improve current therapies against this tumour.

Silencing of membrane-associated sialidase Neu3 diminishes apoptosis resistance and triggers megakaryocytic differentiation of chronic myeloid leukemic cells K562 through the increase of ganglioside GM3.

In chronic myeloid leukemia K562 cells, differentiation is also blocked because of low levels of ganglioside GM3, derived by the high expression of sialidase Neu3 active on GM3. In this article, we studied the effects of Neu3 silencing (40-70% and 63-93% decrease in protein content and activity, respectively) in these cells. The effects were as follows: (a) gangliosides GM3, GM1, and sialosylnorhexaosylceramide increased markedly; (b) cell growth and [(3)H]thymidine incorporation diminished relevantly; (c) as mRNA, cyclin D2, and Myc were much less expressed, whereas cyclin D1 was expressed more like its inhibitor p21; (d) as mRNA, pro-apoptotic proteins Bax and Bad increased with concurrent decrease and increase in the anti-apoptotic proteins Bcl-2 and Bcl-XL, respectively; (e) the apoptosis inducers etoposide and staurosporine were active on Neu3 silencing cells but not on mock cells; (f) as mRNA, the megakaryocytic markers CD10, CD44, CD41, and CD61 increased similar to the case of mock cells stimulated with PMA; (g) the signaling cascades mediated by PLC-beta2, PKC, RAF, ERK1/2, RSK90, and JNK were largely activated. The induction of a GM3-rich ganglioside pattern in K562 cells by treatment with brefeldin A elicited a phenotype similar to that of Neu3 silencing cells. In conclusion, upon Neu3 silencing, K562 cells show a decrease in proliferation, propensity to undergo apoptosis, and megakaryocytic differentiation.

Polyphenol-enriched fractions from Sicilian grape pomace: HPLC-DAD analysis and antioxidant activity.

On the basis of a preliminary screening of seven different samples of Sicilian grape pomace, the 'Nerello Mascalese' sample NM2 was selected for an ethanol preparative extraction. The defatted NM2 EtOH extract was subjected to DPPH() and GAE assays, showing good radical scavenging activity (SC(50)=9.9 microg/mL) and a GAE value of 397.7 mg/g extract. HPLC-DAD analysis of NM2 extract allowed a quantitative determination of the main anthocyanins (AN) and flavonols/flavonol glycosides (FL/FG). Aliquots of the NM2 extract were subjected to three different fractionation protocols (FP1, FP2 and FP3). The fractions were examined by DPPH() and GAE assays, and subjected to HPLC-DAD analysis for the quantitative determination of the main AN and FL/FG. FP3 allowed obtaining a polyphenol-enriched fraction with SC(50)=14.8 microg/mL and GAE=184.1mg/g of fraction, accounting for only 1.3% in weight of the EtOH extract. Some considerations about the relationship between antioxidant activity and AN/FL/FG HPLC-DAD profiles are also reported.

Erythrocyte glycohydrolases in subjects with trisomy 21: could Down's syndrome be a model of accelerated ageing?

We studied some erythrocyte glycohydrolases, erythrocyte membrane fluidity, plasma hydroperoxides and total antioxidant defences in 23 Down syndrome (DS) individuals in comparison with healthy age-matched and elderly controls. With regard to erythrocyte plasma membrane fluidity, plasma hydroperoxides and total plasma oxidative defences, DS subjects resembled the age-matched controls more than the elderly ones. Membrane glycohydrolases in DS, however, presented a pattern partly similar to age-matched controls and partly to elderly controls. Concerning cytosol glycohydrolases, DS subjects had lower levels of hexosaminidase and N-acetyl-beta-D-glucosaminidase, the latter specific for the hydrolysis of GlcNAc residues O-linked to proteins. In general, erythrocyte membrane and cytosol glycohydrolases decreased during erythrocyte ageing in DS subjects and in all controls. The increased levels of the same enzymes in DS plasma might be attributed to an alteration of their release-uptake mechanisms between the two different compartments, on account of the higher plasma hydroperoxide levels. These findings indicate that erythrocyte ageing in DS differs partially from that of age-matched and elderly controls. In any case, the accelerated ageing seen in DS is no fully comparable to physiological ageing.

Erythrocyte membrane alterations during ageing affect beta-D-glucuronidase and neutral sialidase in elderly healthy subjects.

In this study, a comparison between elderly (>70 years) and young subjects reveals that elder people are subject to a higher oxidative stress, which causes an increase in plasma hydroperoxide levels (18%) and a decrease in antioxidant defenses (25%). Moreover, the marked decrease of the erythrocyte membrane fluidity observed in elderly subjects was likely to affect the behavior of some membrane glycohydrolases. In fact, a significant decrease of beta-d-glucuronidase and neutral sialidase (30 and 50%, respectively) was detected. Activity differences were also observed when erythrocytes were further distinguished according to their biological age. Striking differences between young and elderly subjects were observed for beta-d-glucuronidase and neutral sialidase in young and senescent erythrocytes, respectively. Overall beta-d-glucuronidase decreases with the subjects' age, while neutral sialidase levels are higher in the elderly. This is presumably due to the localization of these enzymes in distinct plasma membrane micro-domains, which are differently peroxidized. A possible role of these enzymes in signaling praecox membrane alterations has also been evidenced.

Antifeedant constituents from Fagara macrophylla.

Analysis of the polar fractions of an EtOH extract obtained from the bark of the African medicinal plant Fagara macrophylla led to the isolation and identification of the alkaloids oblongine (6), tembetarine (7) and magnoflorine (8) and the flavonoid hesperidin (9). These compounds, together with other metabolites (1--5) previously isolated from F. macrophylla, were tested for antifeedant activity in a binary-choice bioassay. The acridone alkaloid xanthoxoline (4) was found to have a potent antifeedant activity against larvae of both Spodoptera frugiperda and S. littoralis. 1-Hydroxy-3-methoxy-N-methyl-acridone (2), arborinine (3), tembetarine (7) and magnoflorine (8) were antifeedant against S. frugiperda.

Different behavior of ghost-linked acidic and neutral sialidases during human erythrocyte ageing.

Acidic and neutral sialidases (pH optimum 4.7 and 7.2, respectively) were assayed on human circulating erythrocytes during ageing. The assays were performed on intact erythrocytes and resealed erythrocyte ghost membranes. From young to senescent erythrocytes the acidic sialidase featured a 2.7-fold and 2.5-fold decrease in specific activity when measured on intact cells or resealed ghost membranes, whereas the neutral sialidase a 5-fold and 7-fold increase, respectively. The Ca2+-loading procedure was employed to mimic the vesiculation process occurring during erythrocyte ageing. Under these conditions the released vesicles displayed an elevated content of acidic sialidase, almost completely linked through a glycan phosphoinositide (GPI) anchor but no neutral sialidase activity, that was completely retained by remnant erythrocytes together with almost all the starting content of sialoglycoconjugates. The loss with vesiculation of acidic sialidase with a concomitant relative increase of neutral sialidase was more marked in young than senescent erythrocytes. The data presented suggest that during ageing erythrocytes loose acidic sialidase, and get enriched in the neutral enzyme, the vesiculation process, possibly involving GPI-anchors-rich membrane microdomains, being likely responsible for these changes. The enhanced neutral sialidase activity might account for the sialic acid loss occurring during erythrocyte ageing.

Calorimetric evidence of differentiated transport of limonin and nomilin through biomembranes.

The effect exerted by two structurally similar limonoids possessing antifeedant and anticancer activity, limonin and nomilin, on the thermotropic behavior of model membranes constituted by dimyristoylphosphatidylcholine (DMPC) vesicles was studied by differential scanning calorimetry. Attention was directed to evaluate modifications in phytochemical-lipid interaction induced by compound structure and lipophilicity and to evidence their different membrane penetration. The two examined compounds, when dispersed in liposomes during their preparation, were found to exert a very different action on the L(beta)-L(alpha) gel-to-liquid crystal phase transition of DMPC multilamellar vesicles. Nomilin caused a detectable effect on the transition temperature (T(m)), shifting it toward lower values with a concomitant small decrease of the associated enthalpy (DeltaH) changes, while limonin was not able to modify the lipid vesicles thermotropic behavior. Modifications induced by nomilin were a function of phytochemical concentration, while the different behavior of limonin can be due to the different polarity induced by the presence of the single A ring in nomilin that possesses an acetyl group versus the A,A' ring system of limonin. Solid limonoids and aqueous dispersions of multilamellar (MLVs) or unilamellar vesicles (LUVs) (limonoids molar fraction 0. 045, 0.12, and 0.18) were left in touch for long incubation times at temperatures higher than T(m) to detect their spontaneous transfer through the medium. By following this procedure, no interaction was detected for limonin with lipid vesicles. The rate of transfer and interaction of nomilin was a function of the kind of vesicle species (faster for LUV, slower for MLV). The interaction, monitored by compound transfer from the solid phytochemical to the lipidic species after several periods of incubation, was on the same order as that detected by preparation carried out in organic solvent. The obtained results can be explained in terms of compound hydrophobicity, and a relation between compound structure and membrane interaction can be suggested. This allows the membrane interaction with nomilin, but the low water solubility of limonin hinders or totally blocks its transfer through the aqueous medium.

An unusual nitrogenous terphenyl derivative from fruiting bodies of the basidiomycete Sarcodon leucopus.

A new nitrogenous metabolite with a p-terphenyl core, sarcodonin (3), has been isolated from fruiting bodies of the basidiomycete Sarcodon leucopus. The structure of 3 was determined through a careful study of its peracetate 4, by use of an array of spectroscopic techniques (including (15)N NMR, gradient-enhanced, and reverse-detected 2D NMR experiments) and chemical degradation. ROESY data and molecular mechanics (MM+) calculations led to assignment of the absolute configuration of 4. Compound 3 exhibited moderate cytotoxicity against KB and P-388 tumor cell cultures.

Bioactive constituents of the bark of Parkia biglobosa.

In the frame of a systematic analysis of African plants used for the 'cure salée', from the bark of Parkia biglobosa, a long-chain ester of trans-ferulic acid (1) has been isolated together with an unseparable mixture of long-chain cis-ferulates (2a-e). In addition, lupeol, 4-O-methyl-epi-gallocatechin, epi-gallocatechin, epi-catechin 3-O-gallate, and epi-gallocatechin 3-O-gallate were isolated.

Corneal endothelium evaluation in type I and type II diabetes mellitus.

BACKGROUND: The purpose of this study is to evaluate the corneal endothelium in type I and type II diabetic patients. METHODS: Seventy-five diabetics divided into type I and type II groups and 62 healthy volunteers took part in the study. The mean endothelial cell density and morphology, and the central corneal thickness were evaluated and statistical analysis was done. RESULTS: All evaluated parameters were found to be significantly different in both diabetic groups with reduction of the mean cell density of 5% in type II and of 11% in type I diabetes with respect to the normal age-matched control group. Important alterations of endothelial morphology were observed. The central corneal pachymetry was significantly higher in diabetics, with p < 0.01 in the type I group and p < 0.05 in the type II group. CONCLUSION: It is concluded that corneal endothelium in diabetics should still be considered as a tissue under continuous metabolic stress with consequent high vulnerability, especially in case of any external insult such as a surgical procedure.

Using pictographs to enhance recall of spoken medical instructions.

Pictographs have been used in nonliterate societies to help people remember spoken instructions and, today, they could be used to help nonliterate people remember spoken medical instructions. This study tested the hypothesis that pictographs can improve recall of spoken medical instructions. Twenty-one junior college subjects listened to lists of 38 actions for managing fever and 50 actions for managing sore mouth. One of the action lists was accompanied by pictographs during both listening and recall while the other was not. Subjects did not see any written words during the intervention and, therefore, relied entirely on memory of what they heard. Mean correct recall was 85% with pictographs and 14% without (P < 0.0001) indicating that pictographs can enhance memory of spoken medical instruction--often to a very high level. For this technique to be clinically useful, further research is needed on how to achieve accurate recall of large amounts of medical information for long periods of time by nonliterate patients. By viewing illiteracy as a memory problem, the large body of research on learning and memory can be utilized in designing education materials for this group.

Cytotoxic diterpenoids from the brown alga Dilophus ligulatus.

A new xenicane-type diterpene, dilopholide [5], and four known diterpenoids, acetoxycrenulide [1], acetylcoriacenone [2], and its epimer isoacetylcoriacenone [3], and hydroxyacetyldictyolal [4], have been isolated from the brown alga Dilophus ligulatus [syn. spiralis (Montagne) Hamel]. The structure of dilopholide [5] was elucidated by spectroscopic methods, including the concerted application of a number of 2D nmr techniques, including 1H-1H COSY, heteronuclear proton-carbon chemical shift correlation (HETCOSY), and long-range HETCOSY. The cytotoxic activity of compounds 1-5 has been examined against several types of mammalian cells: human nasopharynx carcinoma cells (KB), human lung carcinoma cells (NSCLC-N6), murine leukemia cells (P-388), and murine leukemia cells expressing the multi-drug-resistance gene, mdr (P-388/DOX).

Bioactive Diterpenoids Isolated from Dilophus ligulatus.

Nine diterpenoids, acetyldictyolal ( 1), epoxyoxodolabelladiene ( 2), dictyotalide B ( 3), neodictyolactono ( 4), pachylactone ( 5), the acetals 6A and 6B, isoacetoxycrenulatin ( 7), and dictyolactone ( 8) were isolated from the brown alga DILOPHUS LIGULATUS (Kütz.) Feldm. Their structures have been elucidated by comparison of mass, IR, (1)H- and (13)C-NMR spectra with reported literature data. Compounds 1, 2, 4, 7, and 8 exhibited antifungal activity. Cytotoxic activity against several types of mammalian cells (KB, P-388, P-388/DOX, and NSCLCN6-L16) in culture was examined for the 8 diterpenoids. Some of them showed stronger cyto-toxicity than mercaptopurine which was used as a positive control in this study.

Cytotoxic activity of tetraprenylphenols related to suillin, an antitumor principle from Suillus granulatus.

Cytotoxic activity against three tumor cell lines (KB, P-388, and NSCLC-N6) has been determined for 14 natural and semisynthetic tetraprenylphenols. Structure-activity relationships have been examined.

Antimicrobial tetraprenylphenols from Suillus granulatus.

From fruit bodies of the basidiomycete Suillus granulatus the tetraprenylphenols 2-6 were isolated. Their structures were elucidated by means of chemical and spectroscopic methods. Compounds 4 and 5 possess antimicrobial properties.

An antitumor principle from Suillus granulatus.

An antitumor principle from Suillus granulatus has been identified as suillin. In vitro and in vivo activities against P-388 leukemia have been determined.

Molluscicidal and antifungal activity of diterpenoids from brown algae of the family dictyotaceae.

17 diterpenoids isolated from brown algae of the family DICTYOTACEAE have been evaluated for molluscicidal and antifungal activity. Significant molluscicidal activity is exhibited by the two geometrical isomers 9 and 10. The assessment of structure-activity relationships has been considered.