Dental unit water content and antibiotic resistance of Pseudomonas aeruginosa and Pseudomonas species: a case study

Background Many studies consider the contamination of dental unit waterlines (DUWLs), but few of them have studied the possible presence of antibiotic resistant Pseudomonas aeruginosa in the DUWLs. Aims Investigation of the presence of P. aeruginosa and Pseudomonas spp. strains in DUWLs and evaluation of their resistance to six antibiotics (ceftazidime, netilmicin, piperacillin/tazobactam, meropenem, levofloxacin, colistin sulfate) at a public dental clinic in Milan, Italy. Results Dental units were contaminated by P. aeruginosa with loads of 2-1,000 CFU/L and were mainly located on the mezzanine floor, with a range of 46-54%, while Pseudomonas spp. were primarily found on the first and second floors, ranging from 50 to 91%. P. aeruginosa was antibiotic resistant in 30% of the strains tested, andPseudomonas spp. in 31.8% . Cold water from controls was also contaminated by these microorganisms. Conclusion Monitoring antibiotic resistance in the water and adopting disinfection procedures on DUs are suggested within the Water Safety Plan

Overexpression of Osmyb4 enhances compatible solute accumulation and increases stress tolerance of arabidopsis thaliana

In this paper, we report the metabolic and molecular changes in response to cold and drought induced in Osmyb4 transgenic Arabidopsis thaliana compared with the wildtype (WT). The rice Osmyb4 gene codes for a transcription factor (Myb4) induced by cold treatment and, in Arabidopsis transgenic plants, improves cold and freezing tolerance [Vannini C, Locatelli F, Bracale M, Magnani E, Marsoni M, Osnato M, Mattana M, Baldoni E, Coraggio I (2004) Plant J 37: 115-127]. Here, we report the ability of Myb4 to induce also drought tolerance in Arabidopsis transgenic plants. By the use of nuclear magnetic resonance (NMR) and enzymatic assays, we showed that several compatible solutes (glucose, fructose, sucrose, proline, glycine betaine and sinapoyl malate) accumulate in higher amount in Osmyb4-overexpressing plants with respect to the WT, both under normal and stress conditions. Considering proline, we also found that in transgenic plants the levels of the mRNAs coding for \u3941- pyrroline-5-carboxylate synthase (EC not assigned) and for \u3941- pyrroline-5-carboxylate dehydrogenase (EC 1.5.1.12) were higher and lower, respectively. The constitutive activation of several stress-inducible pathways and different kinetics in the accumulation of several metabolites, in Myb4 transgenic plants, may represent an advantage to prepare plants to face the stress condition. Moreover, these results taken together suggest that Myb4 integrates the activation of multiple components of stress response

New "clickable" polymeric coating for glycan microarrays

The interaction of carbohydrates with a variety of biological targets, including antibodies, proteins, viruses and cells are of utmost importance in many aspects of biology. Glycan microarrays are increasingly used to determine the binding specificity of glycan-binding proteins. In this study, a novel slide is reported for the fabrication of glycan arrays that combines the higher sensitivity of a layered Si-SiO2 with a novel approach to form a polymeric coating easily modifiable by subsequent click reaction. The alkyne-containing copolymer, adsorbed from an aqueous solution, produces a coating by a single step procedure and serves as a soft, tridimensional support for the oriented immobilization of carbohydrates via azide/alkyne Cu(I) catalyzed "click" reaction. The equilibrium and kinetics parameters of the interaction of Concanavalin A with eight synthetic glycans were determined using fluorescence microarray and Reflective Phantom Interface (RPI), a recently proposed optical label-free detection approach. The enhancement of fluorescence provided by the Si-SiO2 slides enabled to extend the limit of detection at lower surface densities of lectins, in turn enabling the study of the interaction for a wide range of glycans surface density. Equilibrium dissociation constants of a few nM were extracted for multivalent glycan-lectin binding, mimicking the conditions of biological membranes, whereas hundreds of nM were observed at the lower glycan surface densities

Monolithically integrated DBR waveguidelaser and intensity modulator in erbiumdoped LiNbO3

For the first time, a DBR laser has been integrated with a Mach Zehnder intensity modulator in Er diffusion doped, Z cut LiNbO,, with Ti indiffused waveguides and dry etched Bragg gratings. The monolithically integrated device has a threshold of 54.8mW incident pump power (hp = 1480nm) and emits, in a single longitudinal mode, up to 0.65 mW CW output power at hs = 1561nm. The Mach-Zehnder type intensity modulator has an optical bandwidth > 3GHz

Characterization of the biogenic volatile organic compounds (BVOCs) and analysis of the PR1 molecular marker in Vitis vinifera L. inoculated with the nematode Xiphinema index

Upon pathogen attack, plants very quickly undergo rather complex physico-chemical changes, such as the production of new chemicals or alterations in membrane and cell wall properties, to reduce disease damages. An underestimated threat is represented by root parasitic nematodes. In Vitis vinifera L., the nematode Xiphinema index is the unique vector of Grapevine fanleaf virus, responsible for fanleaf degeneration, one of the most widespread and economically damaging diseases worldwide. The aim of this study was to investigate changes in the emission of biogenic volatile organic compounds (BVOCs) in grapevines attacked by X. index. BVOCs play a role in plant defensive mechanisms and are synthetized in response to biotic damages. In our study, the BVOC profile was altered by the nematode feeding process. We found a decrease in \u3b2-ocimene and limonene monoterpene emissions, as well as an increase in \u3b1-farnesene and \u3b1-bergamotene sesquiterpene emissions in nematode-treated plants. Moreover, we evaluated the PR1 gene expression. The transcript level of PR1 gene was higher in the nematode-wounded roots, while in the leaf tissues it showed a lower expression compared to control grapevines

Legionella detection in water networks as per iso 11731:2017: Can different filter pore sizes and direct placement on culture media influence laboratory results?

Determination of Legionella concentrations in water networks is useful for predicting legionellosis risks. The standard culture technique using concentration with membranes filters is the most commonly used method for environmental surveillance of Legionella. The aim of this study was to verify whether filtration with different filter pore sizes (0.2 and 0.45 \ub5m) according to (ISO) 11731:2017, followed by directly placing them on culture media, can influence Legionella detection. Three laboratories participated in an experimental study that tested a known suspension of Legionella pneumophila (Lpn) serogroup 1 (ATCC 33152) (approximate final cell density of 15 CFU/mL). E. coli (ATCC 11775) and Pseudomonas aeruginosa (ATCC 25668) were included as control tests. The average (95% CI) percentage of recovery of Lpn was 65% using 0.45-\ub5m filters and 15% using 0.2-\ub5m filters (p < 0.0001). For control tests, the average (95% CI) percentage of recovery was higher with 0.45 vs. 0.2 \ub5m filters: 97% vs. 64% for Escherichia coli (p < 0.00001) and 105% vs. 97% (p = 0.0244) for P. aeruginosa. Our results showed that the 0.45-\ub5m filters provided the greatest detection of Legionella. Because the current national guidelines leave the choice of membrane porosity to the operator, experimental studies are important for directing operators towards a conscious choice to standardize Legionella environmental surveillance methods