The effect of thermal treatment on antibacterial properties of nanostructured TiO<Subscript>2</Subscript>(N) films illuminated with visible light

This work focuses on the photocatalytic performances and antibacterial activity of nitrogen doped TiO₂ nanosystems with three and five layers obtained by a sol-gel route, followed by thermal treatment in oxygen or ammonia atmosphere at temperatures between 400 and 1000°C. Subsequently, the antibacterial activity of the obtained nanosystems on the Escherichia coli cells are determined and discussed. The obtained results show a significant dependence of the functional performances on the system’s composition. In particular, the antimicrobial activity of nitrogen-doped TiO₂ films is correlated with the temperature of thermal treatment and illumination time with visible artificial light.     

Prolactin induces chitotriosidase expression in human macrophages through PTK,PI3‐K,and MAPK pathways

We previously reported that prolactin (PRL) induces chitotriosidase (CHIT‐1) mRNA expression in human macrophages. In this investigation we determined the signaling pathways involved in CHIT‐1 induction in response to PRL. The CHIT‐1 induction PRL‐mediated was reduced by wortmannin and LY‐294002, inhibitors of phosphatidylinositol 3‐kinase (PI3‐K) and by genistein an inhibitor of protein tyrosine kinase (PTK). Pre‐treatment of macrophages with SB203580, a specific inhibitor of the mitogen‐activated kinases (MAPK) p38, or with U0126, an inhibitor of MAPK p44/42, prevented both basal and exogenous PRL‐mediated CHIT‐1 expression. No significant effects on CHIT‐1 induction PRL‐mediated were observed with a protein kinase C inhibitor (PKC), rottlerin, or with an Src inhibitor, PP2, or with JAK2 inhibitor, AG490. In addition, PRL induced a phosphorylation of AKT that was prevented both by the two MAPK inhibitors SB203580 and U0126 and by the PI3‐K inhibitors wortmannin and LY‐294002. In conclusion, our results indicate that PRL up‐regulated CHIT‐1 expression via PTK, PI3‐K, MAPK, and signaling transduction components. J. Cell. Biochem. 107: 881–889, 2009. © 2009 Wiley‐Liss, Inc.     

Prostate cancer regulatory networks

Although the timing with which common epithelial malignancies arise and become established remains a matter of debate, it is clear that by the time they are detected these tumors harbor hundreds of deregulated, aberrantly expressed or mutated genes. This enormous complexity poses formidable challenges to identify gene pathways that are drivers of tumorigenesis, potentially suitable for therapeutic intervention. An alternative approach is to consider cancer pathways as interconnected networks, and search for potential nodal proteins capable of connecting multiple signaling networks of tumor maintenance. We have modeled this approach in advanced prostate cancer, a condition with current limited therapeutic options. We propose that the integration of three signaling networks, including chaperone‐mediated mitochondrial homeostasis, integrin‐dependent cell signaling, and Runx2‐regulated gene expression in the metastatic bone microenvironment plays a critical role in prostate cancer maintenance, and offers novel options for molecular therapy. J. Cell. Biochem. 107: 845–852, 2009. © 2009 Wiley‐Liss, Inc.     

Oxytocin stimulates in vitro angiogenesis via a Pyk-2/Src-dependent mechanism

We previously reported that the hypothalamic hormone oxytocin (OT), best known for its uterotonic activity, also stimulates migration and invasion in human umbilical vein endothelial cells (HUVECs), thus suggesting a possible role for the peptide in the regulation of angiogenesis. We identified the Gq coupling of OT receptors (OTRs) and phospholipase C (PLC) as the main effectors of OT's action in HUVECs. Moreover, the pro-migratory effect of OT required the OTR-induced activation of the phosphatidylinositol-3-kinase (PI-3-K)/AKT/endothelial nitric oxide synthase (eNOS) pathway. To better characterize the proposed pro-angiogenic effect of OT in HUVECs, we have now utilized a three-dimensional (3-D) in vitro angiogenesis assay, and demonstrated that OT stimulates the outgrowth of capillary-like structures from HUVEC spheroids to an extent comparable to that of vascular endothelial growth factor (VEGF). This OT effect was abolished by inhibitors of PLC, PI-3-K and Src kinase. It was also found that OT phosphorylates proline-rich tyrosine kinase-2 (Pyk-2) and Src kinase in a PLC- and calcium-dependent manner. Furthermore, knockdown of Pyk-2 expression by RNA interference markedly impaired Src phosphorylation, migration and endothelial cell sprouting induced by OT. In conclusion, by using a pharmacological and genetic approach, the OT pro-angiogenic action and the cascade of intracellular signals responsible for it were defined by showing for the first time that OT, by interacting with its Gq-coupled receptor, induces HUVEC capillary outgrowth via Pyk-2 phosphorylation, which activates Src which in turn activates the PI-3-K/AKT pathway.     

Lack of evidence for meteorological effects on infradian dynamics of testosterone

Climatic factors are known to influence the endocrine system. Previous studies have shown that circannual seasonal variations of testosterone might be partly explained by changes in air temperature. Whether infradian variations are affected by meteorological factors is unknown. To analyze possible effects of meteorological parameters on infradian variations of salivary testosterone levels in both sexes, daily salivary testosterone levels were measured during 1 month in 14 men and 17 women. A correlation analysis between hormonal levels and selected meteorological parameters was performed. The results indicate that high testosterone levels are loosely associated with cold, sunny and dry weather in both sexes. However, only the correlations between testosterone and air temperature (men) and actual cloudiness (women) were statistically significant (p < 0,05). Although some correlations reached the level of statistical significance, the effects of selected meteorological parameters on salivary testosterone levels remain unclear. Further longer-term studies concentrating on air temperature, cloudiness and average relative humidity in relation to the sex hormone axis are needed.     

Epitope Mapping of a Bactericidal Monoclonal Antibody against the Factor H Binding Protein of Neisseria meningitidis

The factor H binding protein (fHbp) is a 27-kDa membrane-anchored lipoprotein of Neisseria meningitidis that allows the survival of the bacterium in human plasma; it is also a major component of a universal vaccine against meningococcus B.In this study, we used nuclear magnetic resonance spectroscopy, mutagenesis, and in silico modeling to map the epitope recognized by MAb502, a bactericidal monoclonal antibody elicited by fHbp. The data show that the antibody recognizes a conformational epitope within a well-defined area of the immunodominant C-terminal domain of the protein that is formed by two loops connecting different β-strands of a β-barrel and a short α-helix brought in spatial proximity by the protein folding. The identification of the protective epitopes of fHbp is an important factor for understanding the mechanism(s) of an effective immune response and provides valuable guidelines for designing variants of the protein able to induce broadly protective immunity.     

The evaluation of the factors that cause aggregation during recombinant expression in E. coli is simplified by the employment of an aggregation-sensitive reporter

Background  

The yields of soluble recombinant proteins expressed in bacteria are often low due to the tendency of the heterologous proteins to form aggregates. Therefore, aggregation reporters have been envisaged to simplify the comparison among different expression conditions and to speed up the identification of suitable protocols that improve the solubility. The probe we used is composed by an IbpAB promoter specifically activated by protein aggregates fused to a sequence coding the β-galactosidase, the activity of which becomes, therefore, indicative of the aggregation degree.     

A bioactive collagen-β tricalcium phosphate scaffold for tissue engineering

Collagen-phosphate composites (COL/β-TCP) are novel materials that have the potential to be used as bone analogues. The aim of our study was to develop a porous bioactive material composed of type I collagen, the main bone protein and tricalcium phosphate, the mineral phase of natural bone, and investigate their in vitro biocompatibility in a human dermal fibroblast culture system. In order to obtain the bioactive materials, type I collagen was isolated from bovine tendon and characterized by physicochemical methods. β-TCP was obtained from calcium carbonate by thermal decomposition at 900 °C temperature. The powder was examined with X-ray diffraction. Two variants of COL/β-TCP scaffolds (P1 and P2) were prepared and examined by scanning electron microscopy. Our results revealed a microporous structure with small white aggregates of β-TCP, non-homogenous scattered in the collagen framework without any preferential orientation. The biocompatibility of the obtained scaffolds was tested by biochemical and histological methods on human fibroblast cultures. Both materials acted as good subtrates for human dermal fibroblast proliferation and migration.     

Evaluation of the phenotypic characteristics of coliform bacteria recovered with two methods: the European Drinking Water Directive reference method and the Colilert 18/Quanti-Tray™ system

Summary The taxonomy of the species belonging to Enterobacteriaceae has undergone a series of revisions. As a consequence, the new classification has caused the analytical detection methods to be updated. According to the European Drinking Water Directive 98/83/CE coliforms/Escherichia coli have to be determined with the ISO 9308-1 reference method. Many technical drawbacks of the procedure as well as limitations regarding the recent taxonomy of coliforms have been pointed out by laboratories working in water quality control. In our investigation, water was analyzed in parallel with the reference method and the rapid Colilert 18/Quanti-Tray™ system. Phenotypic characteristics of isolates were recorded for the verification of the response of the two methods to the new taxonomic approach. Results obtained with the ISO standard confirmed the limitations of the test. In fact, in addition to difficulties linked to the readability of results, it failed to detect a significant proportion of coliforms and E. coli in water. Furthermore, it allowed the growth of microorganisms belonging to other groups. The Colilert 18/Quanti-Tray™ system detected a qualitatively and quantitatively higher number of target microorganisms. It also provided results in a shorter time, allowing the simultaneous detection of E. coli and coliforms with no further confirmation steps.