On a quasilinear elliptic differential equation in unbounded domains

Existence and multiplicity results for a variational quasilinear elliptic equation on unbounded domains are proved; the solutions are obtained as critical points of a nonsmooth functional. We consider the case where the functional is coercive or has a saddle-point geometry

THE DOUBLE BOND IN Δ1-2 POSITION OF STEROIDS: A MATTER OF CONTROVERSY IN THE CONTROL OF ILLICIT TREATMENTS OF FARM ANIMALS

Two tight correlated topics were dealt in this thesis: - Bovine urine can result positive for boldenone, an androgenic steroid with the structure of testosterone with a double bond in \u3941-2 position of ring A, and androstadienedione, its 17-oxidized form, in consequence of faecal contamination, mainly through a high neo production in faeces-contaminated urine. A simple in vitro method was developed \u2013 incubation of faecal matter suspended in 0.9% saline \u2013 to induce steroid transformations in faeces, and analyzed the products by liquid chromatography/tandem mass spectrometry, without the need for prior extraction. Androstenedione, androstadienedione, alfa and beta boldenone, testosterone and epitestosterone transformations were investigated. Mutual interconversions of steroids were observed, although 17 beta hydroxy steroids had lower stability if compared with 17 alfa hydroxy and 17-keto steroids. This simple in vitro system proved to be an effective way of studying hormone transformations in faeces and in faeces-contaminated urine. An analogous method, i.e. the direct injection, for LC/MS-MS analysis, of diluted equine urine, without prior extraction, was carried out to evaluate the stability of phase II metabolites of boldenone, testosterone and epitestosterone (glucuronides and sulphates) in intentionally poorly stored urine. Both 17 beta and 17 alfa-glucuronide steroids hydrolyzed to their correspondent hydroxysteroids, but only the 17 beta epimers oxidized to the keto forms. The sulphate compounds showed a complete stability. The transformations were temperature dependent: faster at room temperature than at 4\ub0C, while did not occur in frozen urines. This indicated that proper storage conditions of biological samples are fundamental to avoid microbiological contamination that can cause chemical modifications of androgen steroids. - After a two-year period of the frequent detection of prednisolone-positive bovine urine samples in the Italian region of Lombardy, studies were initiated to investigate the source. The problem of modifications in biological fluids was therefore evaluated also regarding a possible transformation of cortisol and cortisone into prednisolone and prednisone in cattle faeces. The transformation of the II phase metabolite cortisol glucuronide was studied, too. The method consisted once more of incubation of bovine faecal matter suspended in 0.9% saline spiked with cortisol, cortisone and cortisol glucuronide (400 ng/ml). The deconjugation of the conjugated form the and the dehydrogenation in ring A occurred. It was so concluded that also urine contaminated with faeces may be positive for prednisone and prednisolone in the same way as they are positive for boldenone, i.e. as a result of microbiological dehydrogenase activity on cortisol and cortisone. The successive step was to assess the transformation of cortisol and cortisone in urine collected from the bladder at the slaughterhouse (i.e. without faecal contamination) and incubated at 37\ub0C for 24 hours. The influence of deconjugation with beta-glucuronidase from Helix pomatia was assessed, too. Only urine where prednisolone and prednisone were absent and cortisol was higher than 80 ng/mL were used. In this study a liquid-liquid extraction with a mixture of tert-Buthylmethylether:Ethylacetate (80:20) was performed, to concentrate the sample, so raising the sensitivity of the method. The analyses were carried out by LC MS3. It was demonstrated that a relatively high temperature (e.g. due to inappropriate storage conditions or to enzymatic deconjugation), could give results that do not represent the effective presence and concentration of the abovementioned corticosteroids at the moment of the sample collection. However, because of the stressful conditions of the slaughterhouse, the by-production of prednisolone was supposed, together with the increase of cortisol and cortisone. The urines of three dairy cows were therefore collected and analyzed before and after a pharmacological induced stress (intra muscular administration of tetracosactide hexaacetate, an adrenocorticotropic hormone analogue), and before and after slaughter. Prednisolone was occasionally detected in the non-stressful state, but was consistently found in the urine of stressed cows (from 1.01 to 4.08 ng/mL), together with the raise in concentration of urinary cortisol and cortisone, so indicating a possible endogenous production of prednisolone in stressful situations

Técnica de criação de Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) em laboratório utilizando dieta artificial para a produção de insetos visando estudos de comportamento e controle.

Uma técnica para criação e obtenção de todas as fases de desenvolvimento da mariposa-oriental Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) em laboratório (24 +- 2ºC; UR: 70 +- 10%; fotofase: 16h) utilizando dieta artificial foi avaliada e descrita.bitstream/CNPUV/9452/1/bop013.pdfISSN 1981-1004. Disponível também no formato online

Occurrence of antibiotics in mussels and clams from various FAO areas

Filter feeders, like mussels and clams, are suitable bioindicators of environmental pollution. These shellfish, when destined for human consumption, undergo a depuration step that aims to nullify their pathogenic microorganism load and decrease chemical contamination. Nevertheless, the lack of contamination by drugs may not be guaranteed. Antimicrobials are a class of drugs of particular concern due to the increasing phenomenon of antibiotic resistance. Their use in breeding and aquaculture is a major cause of this. We developed a multiclass method for the HPLC\ue2\u80\u93MS/MS analysis of 29 antimicrobials, validated according to the Commission Decision 2002/657/UE guidelines, and applied it to 50 mussel and 50 clam samples derived from various Food and Agricultural Organisation marine zones. The results obtained, indicate a negligible presence of antibiotics. Just one clam sample showed the presence of oxytetracycline at a concentration slightly higher than the European Union Maximum residue limit set for fish

Virome-associated antibiotic-resistance genes in an experimental aquaculture facility

We report the comprehensive characterization of viral and microbial communities within an aquaculture wastewater sample, by a shotgun sequencing and 16S rRNA gene profiling metagenomic approach. Caudovirales had the largest representation within the sample, with over 50% of the total taxonomic abundance, whereas approximately 30% of the total open reading frames (ORFs) identified were from eukaryotic viruses (Mimiviridae and Phycodnaviridae). Antibiotic resistance genes (ARGs) within the virome accounted for 0.85% of the total viral ORFs and showed a similar distribution both in virome and in microbiome. Among the ARGs, those encoding proteins involved in the modulation of antibiotic efflux pumps were the most abundant. Interestingly, the taxonomy of the bacterial ORFs identified in the viral metagenome did not reflect the microbial taxonomy as deduced by 16S rRNA gene profiling and shotgun metagenomic analysis. A limited number of ARGs appeared to be mobilized from bacteria to phages or vice versa, together with other bacterial genes encoding products involved in general metabolic functions, even in the absence of any antibiotic treatment within the aquaculture plant. Thus, these results confirm the presence of a complex phage-bacterial network in the aquaculture environment

Development of a milk-based medium for the selection of urease-defective mutants of Streptococcus thermophilus

Streptococcus thermophilus strains are used in fermented dairy products for their capacity to metabolize lactose into lactic acid. The rate of lactic acid production in milk is of major economic importance, as rapid acidification prevents growth of undesirable microorganisms. It is also of paramount significance for aroma, texture and flavor of the end product. Besides achieving customer satisfaction, improvement of production rate and operational costs incite industrials into selecting fast acidifying strains. Another important trait of S. thermophilus influencing acidification is the urease, which catabolizes urea into ammonia and has a detrimental effect on acidification. Unfortunately, most of the S. thermophilus strains possess the urease, and the urease-negative ones are necessary for industrial applications. Urease activity is a widely distributed activity in S. thermophilus species, and urease-negative strains are rare. The later are however interesting from an industrial point of view, as they may give faster acidification in dairy applications, because lactic acid is not buffered by urea-derived ammonia. Nowadays, the efforts to improve the characteristics of strains for industrial applications are based on natural strategies such as random mutagenesis. This implies the need of a screening method that is efficient in terms of time and success. In this context, the aim of this study was the development of a new medium that allows selection of urease-defective mutants based on S. thermophilus colony morphology. Discrimination capacity of the new medium was verified using previously characterized urease-negative recombinant strains. The new milk-based medium, applied to industrial S. thermophilus strains subjected to UV mutagenesis, allowed the selection of 3 mutants, partially or completely defective in urease activity. Genetic characterization of urease-defective mutants highlighted the presence of nonsense or missense mutations in the ureA, ureC and ureG genes, thus supporting their phenotype. Evaluation of milk acidification revealed increased performance for one out of three urease-defective mutants compared to wild-type strains

Determination of thyreostats in bovine urine and thyroid glands by HPLC–MS/MS

The use of thyreostats in livestock is strictly forbidden by European legislation since 1981. The investigation of thyreostats is commonly performed by their detection as derivatives with 3-iodobenzylbromide. Although it has advantages, the derivatisation procedure can generally cause a decrease in analyte concentrations. With the aim of simplifying the analysis of five thyreostats in both bovine urine and in thyroid glands, two methods were developed without the derivatisation step. Salting-out assisted liquid\u2013liquid extraction was carried out for both matrices, followed by high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry analysis. The methods were validated in agreement with the guidelines of Commission Decision 2002/657/EC. For all the thyreostats evaluated, satisfactory results were achieved; the recovery was within 96\u2013104 % for both the matrices, while precision (coefficient of variation) was less than 20 % for urine and 21 % for thyroid glands. The limits of decision and capacities of detection for all the compounds were lower than the recommended values of 10 \u3bcg L 121 and 10 \u3bcg kg 121, respectively. In urine, the limits of decision ranged from 6.9 to 7.3 \u3bcg L 121, and the capacities of detection ranged from 8.5 to 9.7 \u3bcg L 121, while in thyroid glands these values varied from 6.6 \u3bcg kg 121 to 7.4 \u3bcg kg 121 and from 8.0 \u3bcg g 121 to 9.7 \u3bcg kg 121, respectively. The results obtained show that the methods described are suitable for the direct detection of thyreostats in bovine urine and thyroid glands

Distribution of persistent organic pollutants (POPS) IN wild Bluefin tuna (Thunnus thynnus) from different FAO capture zones

Residues of environmental contaminants in food represent a concern in food safety programs. In this study, the distribution of persistent organic pollutants (POPs) were evaluated in 79 tuna samples from FAO areas 51 (Indian Ocean), 71 (Pacific Ocean), 34 (Atlantic Ocean), and 37 (Mediterranean Sea). 6 polychlorinated biphenyls (PCBs), 16 organochlorines (OCs) and 7 polybrominated biphenyl ethers (PBDEs) were selected as representative compounds according to EFSA POPs monitoring guidelines. An analytical method, based on Accelerated Solvent Extraction (ASE), with an "in-line" clean-up step and GC-MS/MS detection, was developed, validated and applied. PCBs were detected in all FAO areas, with a prevalence of 100% for most of them. In the FAO area 37, only, all PBDEs were detected. Only 5 OCs were detected. The results showed that POPs contamination of tuna reflects FAO area contamination; in particular FAO area 37 was the most polluted. Moreover, tuna muscle was an appropriate matrix for monitoring contamination and for obtaining information about food safety

Feromônios sexuais no manejo de insetos-praga na fruticultura de clima temperado.

bitstream/item/95271/1/Feromonios-ULTIMA-VERSAO-08-07-2013.pdf; bitstream/item/95273/1/Capa-Feromonios.pd

Supercritical biharmonic equations with power-type nonlinearity

The biharmonic supercritical equation $\Delta^2u=|u|^{p-1}u$, where $n>4$ and $p>(n+4)/(n-4)$, is studied in the whole space $\mathbb{R}^n$ as well as in a modified form with $\lambda(1+u)^p$ as right-hand-side with an additional eigenvalue parameter $\lambda>0$ in the unit ball, in the latter case together with Dirichlet boundary conditions. As for entire regular radial solutions we prove oscillatory behaviour around the explicitly known radial {\it singular} solution, provided $p\in((n+4)/(n-4),p_c)$, where $p_c\in ((n+4)/(n-4),\infty]$ is a further critical exponent, which was introduced in a recent work by Gazzola and the second author. The third author proved already that these oscillations do not occur in the complementing case, where $p\ge p_c$. Concerning the Dirichlet problem we prove existence of at least one singular solution with corresponding eigenvalue parameter. Moreover, for the extremal solution in the bifurcation diagram for this nonlinear biharmonic eigenvalue problem, we prove smoothness as long as $p\in((n+4)/(n-4),p_c)$