Effect of hydrogen bonding interaction on the photophysics of α-amino-orcein.

This paper reports for the first time a detailed spectroscopic investigation into the ground- and excited-state properties of α-amino-orcein (α-AO), one of the main components of the orcein dye, in solvents of different proticity and water at different pHs. In order to gain insight into the nature of the involved transitions and excited state deactivation pathways, the study was carried out by means of UV-Visible steady state and ultrafast spectroscopic techniques with the support of quantum mechanical calculations (DFT and TDDFT). The results highlight that the photophysical and photodynamic behaviour of α-AO are highly sensitive to the solvent proticity and pH. In particular, protic environment induces a red shift (55 nm) of the absorption spectrum together with a relevant decrease of the fluorescence quantum yield (from 0.19 in acetonitrile to 6.6 × 10-3 in methanol) and radiative rate constant (two orders of magnitude). A notable red shift is also caused by increasing the pH leading the molecule from monocationic to neutral and then monoanionic form through two deprotonation steps (pKa = 3.539 ±â€¯0.006 and 11.180 ±â€¯0.006). Following deprotonation, the molecule assumes spectral and photophysical properties very similar to those retrieved in protic media. The observed behaviour has been rationalized through the occurrence of hydrogen bonding, likely involving to a greater extent the carbonyl oxygen of α-AO and the protic solvent, that favours the charge delocalization on the whole chromophore as well as fast non-radiative excited state deactivation. The ultrafast spectroscopic investigation revealed in fact the presence, in protic solvent, of a short living component (tens of picoseconds), assignable to solvent complexed S1 state, alongside the long living component (few nanoseconds) observed in aprotic media and attributed to the solvent free S1 state. The results achieved in this study for α-AO provides an important contribution to the interpretation of absorption and fluorescence features of orcein dye mixture in more complex systems (protein based substrates within the many aspects of the cultural heritage and biomedical field) where hydrogen bonds are expected to play a crucial role in mediating the interaction with the environment.

Altered Erythropoiesis in Mouse Models of Type 3 Hemochromatosis.

Type 3 haemochromatosis (HFE3) is a rare genetic iron overload disease which ultimately lead to compromised organs functioning. HFE3 is caused by mutations in transferrin receptor 2 (TFR2) gene that codes for two main isoforms (Tfr2α and Tfr2ß). Tfr2α is one of the hepatic regulators of iron inhibitor hepcidin. Tfr2ß is an intracellular isoform of the protein involved in the regulation of iron levels in reticuloendothelial cells. It has been recently demonstrated that Tfr2 is also involved in erythropoiesis. This study aims to further investigate Tfr2 erythropoietic role by evaluating the erythropoiesis of two Tfr2 murine models wherein either one or both of Tfr2 isoforms have been selectively silenced (Tfr2 KI and Tfr2 KO). The evaluations were performed in bone marrow and spleen, in 14 days' and 10 weeks' old mice, to assess erythropoiesis in young versus adult animals. The lack of Tfr2α leads to macrocytosis with low reticulocyte number and increased hemoglobin values, together with an anticipation of adult BM erythropoiesis and an increased splenic erythropoiesis. On the other hand, lack of Tfr2ß (Tfr2 KI mice) causes an increased and immature splenic erythropoiesis. Taken together, these data confirm the role of Tfr2α in modulation of erythropoiesis and of Tfr2ß in favoring iron availability for erythropoiesis.

Pharmacokinetics and residue depletion of erythromycin in gilthead sea bream Sparus aurata L. after oral administration.

Erythromycin (ERY) is an antibiotic effective against Streptococcus iniae, a microorganism responsible for significant losses in aquaculture. No data are available on the pharmacokinetics and residue depletion of ERY in sea bream. The aim of this study was thus to evaluate the pharmacokinetics of ERY in this species after a single oral administration at 75 mg kg(-1) b.w. and to assess its residue depletion from tissues after prolonged treatment for 10 days. ERY was rapidly absorbed in sea bream (Cmax  = 10.04 µg g(-1) and Tmax =1 h), with a half-life of 9.35 h and an AUC0-24 of 56.81 (h µg mL(-1) ). The data obtained and the evaluation of pharmacokinetic/pharmacodynamic parameters allowed us to hypothesize that dosage used in this study should be effective against S. iniae. A rapid reduction in erythromycin concentrations was observed in tissues, with the drug being detectable only during the first day post-treatment. In Europe, the use of ERY in aquaculture is allowed by off-label prescription with a withdrawal time of 500 °C day(-1) . The absence of ERY residues in tissues already at 24 h post-treatment suggests that ERY in sea bream should not pose human food safety issues.

Pharmacokinetics and residue depletion of erythromycin in rainbow trout Oncorhynchus mykiss (Walbaum).

Erythromycin (ERY) is a drug active against Gram-positive bacteria such as Lactococcus garvieae, a pathogen responsible for an important disease that may cause a substantial decrease in rainbow trout Oncorhynchus mykiss (Walbaum) production, the species of fish most commonly produced in Italy. In the literature, studies on the kinetics behaviour of ERY in fish are limited. Therefore, the aim of the present study was to evaluate the pharmacokinetics of ERY in rainbow trout after a single oral treatment with 75 mg kg⁻¹ body weight (b.w.) of ERY and the residue depletion after multiple oral administration of 75 mg kg⁻¹ b.w. day⁻¹ of ERY for 10 days. Blood concentrations of ERY increased up to 20.24 ± 13.32 µg mL⁻¹ at 6 h, then decreased to 5.97 ± 3.89 µg mL⁻¹ at 24 h. The time during which the antibiotic remains in the bloodstream at concentrations exceeding the MIC (T > MIC) and the area under the serum concentration-time curve (AUC)/MIC are both pharmacokinetic-pharmacodynamic (PK/PD) predictors of ERY efficacy, and the data obtained allowed us to hypothesize that a dosage of 75 mg kg⁻¹ b.w. day⁻¹ of ERY could treat the lactococcosis in trout. Regarding the study of ERY depletion, rapid elimination was observed in tissue (muscle plus adherent skin); in fact the concentrations were below the limit of quantification in all samples (except two) by day 10 post-treatment. ERY is not licensed in Europe for use in aquaculture, and its use is possible only by off-label prescription with a precautionary withdrawal time of 500 degree-days, as established by Directive 2004/28/EC. From the data obtained in this study, a withdrawal time of 8.90 days was calculated, corresponding, in our experimental conditions, to 117.5 degree-days, a value significantly lower than that established by the European directive.

Electronic cigarettes: an evaluation of exposure to chemicals and fine particulate matter (PM).

The "electronic (e-)cigarette" generates intense scientific debate about its use. Its popularity is increasing worldwide as a method to reduce/quit smoking, and to smoke indoors when restrictions on smoking tobacco are present. WHO recommends caution, until its effectiveness in helping smokers is clarified, and the possible harm evaluated. The aim of this study was to assess the content of the aromatic liquid mixture and its vapour and the Particulate Matter (PM) emissions of an Italian brand of e-cigarette and to compare its PM emissions with a conventional cigarette. Propylene glycol (66%) and glycerine (24%) were main components in the liquid, while the flavouring substances were less than 0.1%. The same substances were detected in the vapour in similar proportions. Fine and ultrafine PM emissions were higher for the conventional versus the e-cigarette (e.g.: PM10=922 vs 52 microg/m3; PM1=80 vs 14 microg/m3). The e-cigarette seems to give some advantages when used instead of the conventional cigarette, but studies are still scanty: it could help smokers to cope with some of the rituals associated with smoking gestures and to reduce or eliminate tobacco consumption avoiding passive smoking. However, the e-cigarette causes exposure to different chemicals compared with conventional cigarettes and thus there is a need for risk evaluation for both e-cigarettes and passive steam exposure in smokers and non smokers.

Cross-protection against four species of chicken coccidia with a single recombinant antigen.

A cDNA clone, SO7', from an Eimeria tenella cDNA library was inserted into the high-expression vector pJC264 and was expressed in Escherichia coli as a fusion protein, CheY-SO7', with a molecular mass of approximately 36 kDa. By using the purified recombinant antigen to immunize young chicks, it was demonstrated that a single dose, without adjuvant, not only protected against severe coccidiosis induced by infection with E. tenella but also protected chicks challenged with the heterologous species Eimeria acervulina, E. maxima, and E. necatrix. By using rabbit antiserum raised against recombinant CheY-SO7', Western blot (immunoblot) analysis of sporulated oocysts of all seven major species of chicken coccidia showed that all species tested contained proteins characteristic of the B class of antigens, of which CheY-SO7' is representative. It seems likely that a single B antigen could protect chickens against severe coccidiosis caused by infection with any of these Eimeria species. Although chicks exposed to prolonged, natural infection develop antibodies to B antigen, active immunization of young chicks with a protective dose of CheY-SO7' does not elicit a humoral antibody response, suggesting that the partial protection results from cell-mediated effector mechanisms. In addition, the cross-protective nature of the immunity indicates that the response to B antigen is different from that induced by natural infection, which elicits a species-specific immunity. To date, the protection induced by B antigen immunization, although remarkable for a single recombinant protein, is not sufficient to compete with prophylactic chemotherapy.