Two benthic diatoms, nanofrustulum shiloi and striatella unipunctata, encapsulated in alginate beads, influence the reproductive efficiency of paracentrotus lividus by modulating the gene expression

Physiological effects of algal metabolites is a key step for the isolation of interesting bioactive compounds. Invertebrate grazers may be fed on live diatoms or dried, pelletized, and added to compound feeds. Any method may reveal some shortcomings, due to the leaking of wound-activated compounds in the water prior to ingestion. For this reason, encapsulation may represent an important step of bioassay-guided fractionation, because it may assure timely preservation of the active compounds. Here we test the effects of the inclusion in alginate (biocompatible and non-toxic delivery system) matrices to produce beads containing two benthic diatoms for sea urchin Paracentrotus lividus feeding. In particular, we compared the effects of a diatom whose influence on P. lividus was known (Nanofrustulum shiloi) and those of a diatom suspected to be harmful to marine invertebrates, because it is often present in blooms (Striatella unipunctata). Dried N. shiloi and S. unipunctata were offered for one month after encapsulation in alginate hydrogel beads and the larvae produced by sea urchins were checked for viability and malformations. The results indicated that N. shiloi, already known for its toxigenic effects on sea urchin larvae, fully conserved its activity after inclusion in alginate beads. On the whole, benthic diatoms affected the embryogenesis of P. lividus, altering the expression of several genes involved in stress response, development, skeletogenesis and detoxification processes. Interactomic analysis suggested that both diatoms activated a similar stress response pathway, through the up-regulation of hsp60, hsp70, NF-κB, 14-3-3 ε and MDR1 genes. This research also demonstrates that the inclusion in alginate beads may represent a feasible technique to isolate diatom-derived bioactive compounds

Analisys of surface alterations of Ni-Ti rotary instruments caused by autoclave sterilization

In recent years, rotary nickel–titanium (NiTi) instruments have become popular because of their superior elasticity and resistance to torsional fracture compared to stainless steel hand files (Walia et al. 1988). Furthermore, most recently it has been shown that a TiN hard coating increased the cutting efficiency of NiTi files significantly. To date, the surfaces of NiTi rotary instruments have been analysed using a variety of different techniques. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were widely used to evaluate the topographical characteristics of different kinds of materials and has been accepted as a suitable method for the evaluation of NiTi instrument surfaces (Tripi et al. 2001, Martins et al. 6 2001, Alpati et al. 2003, 2005). Aim of our study was to evaluate by using scanning electrical microscopy (SEM) with Energy dispersive x-ray spectroscopy (EDS), and Atomic Force Microscopy (AFM) the effect of repeated dry heat sterilization on surface characteristics of NiTi rotary instruments

Effects of sodium hypochlorite and ethylenediaminetetraacetic acid on rotary nickel-titanium instruments evaluated using atomic force microscopy.

To use atomic force microscopy (AFM) to evaluate the effects of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on the surface characteristics of ProTaper rotary nickel-titanium instruments.A total of twenty ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) instruments (S1, S2, F1, F2) were divided into five groups: no immersion, immersion in 5.25\% NaOCl for 5 or 10min and immersion in 17\% EDTA for 5 or 10min. Twenty surface areas along 3-mm sections at the tip of the files (perfect squares of 1x1μm) were analysed by AFM operating in contact mode under ambient conditions. Three-dimensional images (400x400 lines) were processed using Gwyddion software, and the roughness average (Ra) and the root mean square value (RMS) of the scanned surface profiles were recorded. Data were analysed by means of anova and paired samples t-test.Three-dimensional AFM images of the surface of ProTaper instruments, including new and those immersed in NaOCl and EDTA solutions, revealed topographic irregularities at the nanometric scale. RMS and Ra values of instruments treated with NaOCl and EDTA solutions were statistically higher than that of the new ones (P<0.05).Atomic force microscopy three-dimensional images and roughness values indicated that short-term contact between NaOCl and EDTA endodontic irrigants and ProTaper instruments caused alterations in the surface of instruments