Effects of simulated microgravity on the development and maturation of dissociated cortical neurons

Although a wealth of evidence supports the hypothesis that some functions of the nervous system may be altered during exposure to microgravity, the possible changes in basic neuronal physiology are not easy to assess. Indeed, few studies have examined whether microgravity affects the development of neurons in culture. In the present study, a suspension of dissociated cortical cells from rat embryos were exposed to 24 h of simulated microgravity before plating in a normal adherent culture system. Both preexposed and control cells were used after a period of 7-10 d in vitro. The vitality and the level of reactive oxygen species of cultures previously exposed did not differ from those of normal cultures. Cellular characterization by immunostaining with a specific antibody displayed normal neuronal phenotype in control cells, whereas pretreatment in simulated microgravity revealed an increase of glial fibrillary acidic protein fluorescence in the elongated stellate glial cells. Electrophysiological recording indicated that the electrical properties of neurons preexposed were comparable with those of controls. Overall, our results indicate that a short time of simulated microgravity preexposure does not affect dramatically the ability of dissociated neural cells to develop and differentiate in an adherent culture system.     

The family name as socio-cultural feature and genetic metaphor: from concepts to methods

A recent workshop entitled "The Family Name as Socio-Cultural Feature and Genetic Metaphor: From Concepts to Methods" was held in Paris in December 2010, sponsored by the French National Centre for Scientific Research (CNRS) and by the journal Human Biology. This workshop was intended to foster a debate on questions related to the family names and to compare different multidisciplinary approaches involving geneticists, historians, geographers, sociologists and social anthropologists. This collective paper presents a collection of selected communications.     

Inhibition of carbonic anhydrase isozymes I and II with natural products extracted from plants, mushrooms and honey

Different natural products and secondary metabolites from mushrooms, teas, honeys, mosses, plants and seaweeds were investigated for their in vitro inhibitory effects on human carbonic anhydrase (hCA, E.C.4.2.1.1) isoforms I and II. Inhibition data were correlated with the total phenol content in the extract and investigated with the pure compounds believed to be responsible for this activity. Methanolic extracts were prepared for 17 such pure chemicals present in the natural products and for 41 diverse natural products. The IC(50) values were in the range of 0.11-66.50 μg/mL against hCA I and of 0.09-54.54 μg/mL against hCA II, respectively. The total phenol content was in the range of 0.02-1318.96 (as milligrams of gallic acid equivalents) per gram of sample. These data offer new insights on possible novel classes of CA inhibitors based on natural products, possessing a range of chemical structures not present in the classical inhibitors with pharmacological applications, such as the sulfonamides and sulfamates.     

Comparative proteomics to evaluate multi drug resistance in Escherichia coli

Drug resistance in food-borne bacterial pathogens is an almost inevitable consequence of the use of antimicrobial drugs, used either therapeutically or to avoid infections in food-producing animals. In the past decades, the spread and inappropriate use of antibiotics have caused a considerable increase of antibiotics to which bacteria have developed resistance and, moreover, bacteria are becoming resistant to more than one antibiotic simultaneously. Understanding mechanisms at the molecular level is extremely important to control multi-resistant strains and to develop new therapeutic strategies. In the present study, comparative proteomics was applied to characterize membrane and cytosolic proteome in order to investigate the regulation of protein expression in multi-resistance E. coli isolated from young never vaccinated water buffalo. Results highlighted differentially expressed proteins under multi drug resistance conditions giving new insights about mechanisms involved in resistance, as quorum sensing mechanisms, and suggesting possible novel bacterial targets to develop alternative antibiotic drugs.     

Mollicutes contamination: A new strategy for an effective rescue of cancer cell lines

Mollicutes contaminations of cellular models can have marked effects on gene expression and cell behaviour in vitro leading to the production of unreliable data, unsafe biopharmaceutical drugs or to the loss of cell culture itself. Fortunately, irreplaceable cell culture can be cured by decontamination with the specific antibiotic regimen. Here, we describe the treatment of 35 mycoplasma-positive cell lines by the use of the novel antibiotic Mycozap^® as well as evaluate its eradication performance versus the well-known routinely employed BM-Cyclins and fluoroquinolones molecules (175 treatments). Our data evidenced: i) the permanent elimination of mycoplasma infection by MycoZap^®, MRA, Enrofloxacin, Ciprofloxacin and BM-Cyclins in 46%, 29%, 40%, 43%, and 57% of the cultures, respectively; ii) a significant correlation between MRA and Ciprofloxacin eradication profile, as determined by the Spearman correlation coefficient (r = 0.3469, p < 0.05); iii) a mycoplasma eradication in 100% of cell lines by the exclusive adoption of MycoZap^®, Ciprofloxacin, Enrofloxacin, BM-Cyclin 1-2 antibiotic regimen, with the MRA exclusion; iv) the MycoZap^® effectiveness even in case of a mycoplasmal load higher than 50 CFU/mL, as for SH-SY5Y and Neuro2A cells.In conclusion, we want to suggest an optimized antibiotic panel to get 100% mycoplasma-clearance especially in case of unique or treatment-resistant cellular models.     

Reduced expression of MECP2 affects cell commitment and maintenance in neurons by triggering senescence: new perspective for Rett syndrome

MECP2 protein binds preferentially to methylated CpGs and regulates gene expression by causing changes in chromatin structure. The mechanism by which impaired MECP2 activity can induce pathological abnormalities in the nervous system of patients with Rett syndrome (RTT) is not clearly understood. To gain further insight into the role of MECP2 in human neurogenesis, we compared the neural differentiation process in mesenchymal stem cells (MSCs) obtained from a RTT patient and from healthy donors. We further analyzed neural differentiation in a human neuroblastoma cell line carrying a partially silenced MECP2 gene. Senescence and reduced expression of neural markers were observed in proliferating and differentiating MSCs from the RTT patient, which suggests that impaired activity of MECP2 protein may impair neural differentiation, as observed in RTT patients. Next, we used an inducible expression system to silence MECP2 in neuroblastoma cells before and after the induction of neural differentiation via retinoic acid treatment. This approach was used to test whether MECP2 inactivation affected the cell fate of neural progenitors and/or neuronal differentiation and maintenance. Overall, our data suggest that neural cell fate and neuronal maintenance may be perturbed by senescence triggered by impaired MECP2 activity either before or after neural differentiation.     

Achromobacter denitrificans renal abscess

We describe a case of a 66-year-old immunocompetent man affected by Achromobacter denitrificans renal abscess related to renal stones. The patient was treated successfully with meropenem 1 g three times daily for 60 days. To our knowledge, this is the first ever case reported of Achromobacter denitrificans renal abscess.     

Blood Cell Mitochondrial DNA Content and Premature Ovarian Aging

Primary ovarian insufficiency (POI) is a critical fertility defect characterized by an anticipated and silent impairment of the follicular reserve, but its pathogenesis is largely unexplained. The frequent maternal inheritance of POI together with a remarkable dependence of ovarian folliculogenesis upon mitochondrial biogenesis and bioenergetics suggested the possible involvement of a generalized mitochondrial defect. Here, we verified the existence of a significant correlation between blood and ovarian mitochondrial DNA (mtDNA) content in a group of women undergoing ovarian hyperstimulation (OH), and then aimed to verify whether mtDNA content was significantly altered in the blood cells of POI women. We recruited 101 women with an impaired ovarian reserve: 59 women with premature ovarian failure (POF) and 42 poor responders (PR) to OH. A Taqman copy number assay revealed a significant mtDNA depletion (P<0.001) in both POF and PR women in comparison with 43 women of similar age and intact ovarian reserve, or 53 very old women with a previous physiological menopause. No pathogenic variations in the mitochondrial DNA polymerase γ (POLG) gene were detected in 57 POF or PR women with low blood mtDNA content. In conclusion, blood cell mtDNA depletion is a frequent finding among women with premature ovarian aging, suggesting that a still undetermined but generalized mitochondrial defect may frequently predispose to POI which could then be considered a form of anticipated aging in which the ovarian defect may represent the first manifestation. The determination of mtDNA content in blood may become an useful tool for the POI risk prediction.     

Distamycin A and derivatives as synergic drugs in cisplatin-sensitive and -resistant ovarian cancer cells

Acquired resistance to cisplatin (cDDP) is a multifactorial process that represents one of the main problems in ovarian cancer therapy. Distamycin A is a minor groove DNA binder whose toxicity has limited its use and prompted the synthesis of derivatives such as NAX001 and NAX002, which have a carbamoyl moiety and different numbers of pyrrolamidine groups. Their interaction with a B-DNA model and with an extended-TATA box model, [Polyd(AT)], was investigated using isothermal titration calorimetry (ITC) to better understand their mechanism of interaction with DNA and therefore better explain their cellular effects. Distamycin A interactions with Dickerson and Poly[d(AT)(6)] oligonucleotides show a different thermodynamic with respect to NAX002. The bulkier distamycin A analogue shows a non optimal binding to DNA due to its additional pyrrolamidine group. Cellular assays performed on cDDP-sensitive and -resistant cells showed that these compounds, distamycin A in particular, affect the expression of folate cycle enzymes even at cellular level. The optimal interaction of distamycin A with DNA may account for the down-regulation of both dihydrofolate reductase (DHFR) and thymidylate synthase (TS) and the up-regulation of spermidine/spermine N1-acetyltransferase (SSAT) caused by this compound. These effects seem differently modulated by the cDDP-resistance phenotype. NAX002 which presents a lower affinity to DNA and slightly affected these enzymes, showed a synergic inhibition profile in combination with cDDP. In addition, their combination with cDDP or polyamine analogues increased cell sensitivity to the drugs suggesting that these interactions may have potential for development in the treatment of ovarian carcinoma.