Hops Germplasm: Phytochemical Characterization of Wild Humulus lupulus of Central and Northern Italy.

Hops are widespread as a wild plant in almost all Northern and Central Italy, and the characterization of wild populations is attracting considerable interest in verifying their potential use. The development of hops as agricultural crop can be an interesting opportunity, both for farms that would have available a new crop to be included in the crop system and for craft breweries interested in characterizing beers with local raw materials. In the present work, 14 wild hop accessions coming from various Italian locations were characterized and compared with 2 commercial varieties (Cascade and Hallertau Taurus) grown in the same environments. The cones were analyzed to measure the content of α- and ß-acids, polyphenols, flavonoids, and the anti-radical power. The α-acid content of wild hops was generally low, while the ß-acid content was very variable and quite high in some samples. The content in polyphenols and flavonoids and the antiradical power were high and generally similar to those of the commercial varieties. Therefore, the analyzed genotypes are not very suitable for use as bitter hops in beer production, while further analysis may indicate a possible use as aroma hops, or for herbal and pharmaceutical purposes, thanks to their antioxidant content.

Characterization of Subcutaneous Fat of Toscano Dry-Cured Ham and Identification of Processing Stage By Multivariate Analysis Approach Based on Volatile Profile.

During ham processing the action of endogenous proteolytic and lipolytic enzymes leads to the development of volatile compounds (VOCs) responsible of typical aromas. Protected Designation of Origin (PDO) of Toscano ham requires at least 12 months of ripening but extended seasoning might improve flavor and economic value. This study aimed at assessing the evolution of color, fatty acids, and VOCs profile in subcutaneous fat, and, among VOCs, at identifying possible markers characterizing different seasoning length. For this purpose, a reduced pool of VOCs was selected by 3 multivariate statistical techniques (stepwise discriminant analysis, canonical discriminant analysis and discriminant analysis) to classify hams according to ripening (<12 months) or seasoning (≥12 months) periods and also to seasoning length (S12, S14, S16, or S18 months). The main VOCs chemical families steadily increased along ripening. Aldehydes and hydrocarbons reached their peaks at S16, acids and ketones remained constant from R6 to S16, whereas esters started decreasing after 12 months of seasoning. Stepwise analysis selected 5 compounds able to discriminate between ripening and seasoning periods, with 1,1-diethoxyhexane and dodecanoic acid being the most powerful descriptors for ripening and seasoning period, respectively. Instead, 12 compounds were needed to correctly classify hams within seasoning. Among them, undecanoic acid methyl ester, formic acid ethyl ester, 2,4,4-trimethylhexane, and 6-methoxy-2-hexanone had a central role in differentiating the seasoning length.

Effects of a Small Increase in Carbon Dioxide Pressure during Fermentation on Wine Aroma.

The present study tested the effect of a slight increase in pressure (from 0 to 1 bar) during the fermentation on the wine aroma profile. Fermentations were carried out with a commercial dry yeast on Sangiovese juice in the absence of berry skins. The wine samples fermented under slight overpressure conditions were found to be significantly different from the control samples produced at atmospheric pressure in relation to several chemical compounds. Concentrations of many esters (i.e., isoamyl acetate, ethyl acetate, ethyl hexanoate, hexyl acetate, ethyl dodecanoate, and ethyl tetradecanoate), and acids (i.e., hexanoic acid, octanoic acid, and decanoic acid) increased, while concentrations of two acids (i.e., isobutyric and isovaleric acid) decreased. These differences, notably the higher concentration of esters, are usually associated with a more intense fruity attribute. Triangular sensory tests revealed that the significant chemical differences were also perceivable; hence, introducing a slight pressure increase during the alcoholic fermentation could be a useful tool in managing the aroma profile of wine.

Filtration Scheduling: Quality Changes in Freshly Produced Virgin Olive Oil.

Filtration is the most widespread stabilisation operation for extra virgin olive oil, preventing microbial and enzymatic changes. However, during the harvest, the workload of olive mills is at its peak. This results in two approaches to filtration: (i) delays it until after harvesting, increasing the risk of degraded oil quality, and (ii) filters it immediately, increasing the workload. The aim of our experiment is to assess the risk of delaying filtration and establish a safe delay time. Changes in the sensory profile and volatile compound contents were evaluated during 30 days in filtered and unfiltered samples. Significant differences were related to filtration: both turbidity grade and microbial contamination; no differences for the legal parameters were found. Two, contrasting, results were obtained with respect to oil quality: (i) the fusty defect, appearing in less than five days in unfiltered oils, leading to the downgrade of the oil's commercial category, and (ii) filtration removing some lipoxygenase volatile compounds. Consequently, a fruity attribute was more pronounced in unfiltered samples until day five of storage; it seems that, from this point, the fusty defect masked a fruity attribute. Hence, filtering within a few days strongly reduced the risk of degraded oil quality compared to a delayed filtration.

Understanding Olive Oil Stability Using Filtration and High Hydrostatic Pressure.

Veiled extra virgin olive oil (VEVOO) is very attractive on the global market. A study was performed to highlight the role of different amounts of water and microorganisms on the evolution of VEVOO quality during storage, using the selective effects of the application of individual or combined filtration and high hydrostatic pressure (HHP) treatments. Four oil processing trials were carried out in four replicates, resulting in a full factorial design with two independent fixed factors: filtration and HPP treatments. The turbidity of all the olive oil samples was characterized. Furthermore, all the olive oil samples were analysed for legal parameters, volatile organic compounds and phenolic compounds during the storage tests. The microbial contamination in the presence of a high level of water activity (>0.6 Aw) was related to the formation of volatile aroma compounds, which were responsible for the "fusty" sensory defect. Furthermore, high water activity values were related to an increase in the hydrolytic degradation rate of the phenolic compounds. The oil turbidity has to be planned and controlled, starting from adjustment of the water content and application of good manufacturing practices.

Multiple internal standard normalization for improving HS-SPME-GC-MS quantitation in virgin olive oil volatile organic compounds (VOO-VOCs) profile.

The commercial value of virgin olive oils (VOOs) strongly depends on their classification, also based on the aroma of the oils, usually evaluated by a panel test. Nowadays, a reliable analytical method is still needed to evaluate the volatile organic compounds (VOCs) and support the standard panel test method. To date, the use of HS-SPME sampling coupled to GC-MS is generally accepted for the analysis of VOCs in VOOs. However, VOO is a challenging matrix due to the simultaneous presence of: i) compounds at ppm and ppb concentrations; ii) molecules belonging to different chemical classes and iii) analytes with a wide range of molecular mass. Therefore, HS-SPME-GC-MS quantitation based upon the use of external standard method or of only a single internal standard (ISTD) for data normalization in an internal standard method, may be troublesome. In this work a multiple internal standard normalization is proposed to overcome these problems and improving quantitation of VOO-VOCs. As many as 11 ISTDs were used for quantitation of 71 VOCs. For each of them the most suitable ISTD was selected and a good linearity in a wide range of calibration was obtained. Except for E-2-hexenal, without ISTD or with an unsuitable ISTD, the linear range of calibration was narrower with respect to that obtained by a suitable ISTD, confirming the usefulness of multiple internal standard normalization for the correct quantitation of VOCs profile in VOOs. The method was validated for 71 VOCs, and then applied to a series of lampante virgin olive oils and extra virgin olive oils. In light of our results, we propose the application of this analytical approach for routine quantitative analyses and to support sensorial analysis for the evaluation of positive and negative VOOs attributes.

Headspace-Solid Phase Microextraction Approach for Dimethylsulfoniopropionate Quantification in Solanum lycopersicum Plants Subjected to Water Stress.

Dimethylsulfoniopropionate (DMSP) and dimethyl sulphide (DMS) are compounds found mainly in marine phytoplankton and in some halophytic plants. DMS is a globally important biogenic volatile in regulating of global sulfur cycle and planetary albedo, whereas DMSP is involved in the maintenance of plant-environment homeostasis. Plants emit minute amounts of DMS compared to marine phytoplankton and there is a need for hypersensitive analytic techniques to enable its quantification in plants. Solid Phase Micro Extraction from Head Space (HS-SPME) is a simple, rapid, solvent-free and cost-effective extraction mode, which can be easily hyphenated with GC-MS for the analysis of volatile organic compounds. Using tomato (Solanum lycopersicum) plants subjected to water stress as a model system, we standardized a sensitive and accurate protocol for detecting and quantifying DMSP pool sizes, and potential DMS emissions, in cryoextracted leaves. The method relies on the determination of DMS free and from DMSP pools before and after the alkaline hydrolysis via Headspace-Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). We found a significant (2.5 time) increase of DMSP content in water-stressed leaves reflecting clear stress to the photosynthetic apparatus. We hypothesize that increased DMSP, and in turn DMS, in water-stressed leaves are produced by carbon sources other than direct photosynthesis, and function to protect plants either osmotically or as antioxidants. Finally, our results suggest that SPME is a powerful and suitable technique for the detection and quantification of biogenic gasses in trace amounts.

Chemical disguise of myrmecophilous cockroaches and its implications for understanding nestmate recognition mechanisms in leaf-cutting ants.

BACKGROUND: Cockroaches of the genus Attaphila regularly occur in leaf-cutting ant colonies. The ants farm a fungus that the cockroaches also appear to feed on. Cockroaches disperse between colonies horizontally (via foraging trails) and vertically (attached to queens on their mating flights). We analysed the chemical strategies used by the cockroaches to integrate into colonies of Atta colombica and Acromyrmex octospinosus. Analysing cockroaches from nests of two host species further allowed us to test the hypothesis that nestmate recognition is based on an asymmetric mechanism. Specifically, we test the U-present nestmate recognition model, which assumes that detection of undesirable cues (non-nestmate specific substances) leads to strong rejection of the cue-bearers, while absence of desirable cues (nestmate-specific substances) does not necessarily trigger aggression. RESULTS: We found that nests of Atta and Acromyrmex contained cockroaches of two different and not yet described Attaphila species. The cockroaches share the cuticular chemical substances of their specific host species and copy their host nest's colony-specific cuticular profile. Indeed, the cockroaches are accepted by nestmate but attacked by non-nestmate ant workers. Cockroaches from Acromyrmex colonies bear a lower concentration of cuticular substances and are less likely to be attacked by non-nestmate ants than cockroaches from Atta colonies. CONCLUSIONS: Nest-specific recognition of Attaphila cockroaches by host workers in combination with nest-specific cuticular chemical profiles suggest that the cockroaches mimic their host's recognition labels, either by synthesizing nest-specific substances or by substance transfer from ants. Our finding that the cockroach species with lower concentration of cuticular substances receives less aggression by both host species fully supports the U-present nestmate recognition model. Leaf-cutting ant nestmate recognition is thus asymmetric, responding more strongly to differences than to similarities.

A volatolomic approach for studying plant variability: the case of selected Helichrysum species (Asteraceae).

The species of Helichrysum sect. Stoechadina (Asteraceae) are well-known for their secondary metabolite content and the characteristic aromatic bouquets. In the wild, populations exhibit a wide phenotypic plasticity which makes critical the circumscription of species and infraspecific ranks. Previous investigations on Helichrysum italicum complex focused on a possible phytochemical typification based on hydrodistilled essential oils. Aims of this paper are three-fold: (i) characterizing the volatile profiles of different populations, testing (ii) how these profiles vary across populations and (iii) how the phytochemical diversity may contribute in solving taxonomic problems. Nine selected Helichrysum populations, included within the H. italicum complex, Helichrysum litoreum and Helichrysum stoechas, were investigated. H. stoechas was chosen as outgroup for validating the method. After collection in the wild, plants were cultivated in standard growing conditions for over one year. Annual leafy shoots were screened in the post-blooming period for the emissions of volatile organic compounds (VOCs) by means of headspace solid phase microextraction coupled with gas-chromatography and mass spectrometry (HS-SPME-GC/MS). The VOC composition analysis revealed the production of overall 386 different compounds, with terpenes being the most represented compound class. Statistical data processing allowed the identification of the indicator compounds that differentiate the single populations, revealing the influence of the geographical provenance area in determining the volatile profiles. These results suggested the potential use of VOCs as valuable diacritical characters in discriminating the Helichrysum populations. In addition, the cross-validation analysis hinted the potentiality of this volatolomic study in the discrimination of the Helichrysum species and subspecies, highlighting a general congruence with the current taxonomic treatment of the genus. The consistency between this phytochemical approach and the traditional morphometrical analysis in studying the Helichrysum populations supports the validity of the VOC profile in solving taxonomic problems.

Increase in the Level of Proinflammatory Cytokine HMGB1 in Nasal Fluids of Patients With Rhinitis and its Sequestration by Glycyrrhizin Induces Eosinophil Cell Death.

OBJECTIVES: The nuclear protein high mobility group protein box 1 (HMGB1) is a proinflammatory mediator that belongs to the alarmin family of proinflammatory mediators, and it has recently emerged as a key player in different acute and chronic immune disorders. Several lines of evidence demonstrate that HMGB1 is actively released extracellularly from immune cells or passively released from necrotic cells. Because of the ability of HMGB1 to sustain chronic inflammation, we investigated whether the protein is present in nasal fluids of patients with different forms of rhinitis. METHODS: HMGB1 levels were evaluated in nasal fluids of healthy subjects or rhinitis patients who were treated or not treated with different treatments. RESULTS: We report that the level of HMGB1 was significantly increased in nasal fluids of patients with allergic rhinitis, patients with NARES (nonallergic rhinitis with eosinophiliac syndrome), as well as patients with polyps. We also found that a formulation containing the HMGB1-binding compound glycyrrhizin (GLT) reduced the HMGB1 content in nasal fluids of rhinitis patients to an extent similar to that with nasal budesonide treatment. We also found that among the cultured human leukocyte populations, eosinophils released higher amounts of HMGB1. Based on the ability of HMGB1 to sustain eosinophil survival and the ability of GLT to inactivate HMGB1, we report that GLT selectively killed cultured eosinophils and had no effect on neutrophils, macrophages, and lymphocytes. CONCLUSION: Collectively, these data underscore the role of HMGB1 in rhinitis pathogenesis and the therapeutic potential of GLT formulations in treatment of chronic inflammatory disorders of the nasal mucosa.

The effect of ripening time on the chemical, textural, volatile and sensorial traits of Bicep femoris and Semimembranosus muscles of the Slovenian dry-cured ham Kraski prsut.

The effect of two ripening times (12 or 16 months) on the chemical, physical, volatile and sensorial properties of Biceps femoris (BF) and Semimembranosus (SM) muscles of Kraski prsut, was studied. Both muscles showed lower water content and higher proteolysis index at 16 than at 12 months. BF had lower lipid contents and higher moisture, salt percentage and proteolysis index than SM. In SM, a decrease of MUFA with time was observed. A higher quantity of total fatty acids was observed for SM than for BF. General increases in hardness, cohesiveness, chewiness and gumminess were observed over time in both muscles. Higher values of force decay coefficient and lower values of hardness, cohesiveness, gumminess and chewiness were found for BF than for SM. Eighty-seven volatile compounds were tentatively identified in both muscles and were more abundant at 16 than at 12 months. Aldehydes were the predominant group followed by acids, alcohols, esters, hydrocarbons, ketones and furans.

Salinity stress constrains photosynthesis in Fraxinus ornus more when growing in partial shading than in full sunlight: consequences for the antioxidant defence system.

BACKGROUND AND AIMS: A major challenge in plant ecophysiology is understanding the effects of multiple sub-optimal environmental conditions on plant performance. In most Mediterranean areas soil salinity builds up during the summer because of low availability of soil water coupled with hot temperatures. Although sunlight and soil salinity may strongly interact in determining a plant's performance, this has received relatively little attention. METHODS: Two-year-old seedlings of Fraxinus ornus were grown outdoors in pots during a Mediterranean summer in either 45 % (shaded plants) or 100 % (sun plants) sunlight irradiance and were supplied with either deionized water or deionized water plus 75 mm NaCl. Morpho-anatomical traits, water and ionic relations, gas exchange and photosystem II performance, concentrations of individual carotenoids, activity of antioxidant enzymes, concentrations of ascorbic acid and individual polyphenols were measured in leaves. Leaf oxidative stress and damage were estimated by in vivo analysis of stable free radicals and ultrastructural analyses. KEY RESULTS: Leaf concentrations of potentially toxic ions did not markedly differ in shaded or sun plants in response to salinity. Leaves of sun plants displayed superior water use efficiency compared with leaves of shaded plants, irrespective of salinity treatment, and had both better stomatal control and higher CO2 carboxylation efficiency than leaves of shaded plants. In the salt-treated groups, the adverse effects of excess midday irradiance were greater in shade than in sun plants. The activity of enzymes responsible for detoxifying hydrogen peroxide decreased in shaded plants and increased in sun plants as a result of salinity stress. In contrast, the activity of guaiacol peroxidase and the concentration of phenylpropanoids increased steeply in response to salinity in shaded plants but were unaffected in sun plants. CONCLUSIONS: It is concluded that salinity may constrain the performance of plants growing under partial shading more severely than that of plants growing under full sun during summer. The results suggest co-ordination within the antioxidant defence network aimed at detoxifying salt-induced generation of reactive oxygen species.

Drought stress has contrasting effects on antioxidant enzymes activity and phenylpropanoid biosynthesis in Fraxinus ornus leaves: an excess light stress affair?

The experiment was conducted using Fraxinus ornus plants grown outside under full sunlight irradiance, and supplied with 100% (well-watered, WW), 40% (mild drought, MD), or 20% (severe drought, SD) of the daily evapotranspiration demand, with the main objective of exploring the effect of excess light stress on the activity of antioxidant enzymes and phenylpropanoid biosynthesis. Net CO2 assimilation rate at saturating light and daily assimilated CO2 were significantly smaller in SD than in WW and MD plants. Xanthophyll-cycle pigments supported nonphotochemical quenching to a significantly greater extent in SD than in MD and WW leaves. As a consequence, the actual efficiency of PSII (Φ(PSII)) was smaller, while the excess excitation-energy in the photosynthetic apparatus was greater in SD than in WW or MD plants. The concentrations of violaxanthin-cycle pigments relative to total chlorophyll (Chl(tot)) exceeded 200 mmol mol⁻¹ Chl(tot) in SD leaves at the end of the experiment. This leads to hypothesize for zeaxanthin a role not only as nonphotochemical quencher, but also as chloroplast antioxidant. Reductions in ascorbate peroxidase and catalase activities, as drought-stress progressed, were paralleled by greater accumulations of esculetin and quercetin 3-O-glycosides, both phenylpropanoids having effective capacity to scavenge H2O2. The drought-induced accumulation of esculetin and quercetin 3-O-glycosides in the vacuoles of mesophyll cells is consistent with their putative functions as reducing agents for H2O2 in excess light-stressed leaves. Nonetheless, the concentration of H2O2 and the lipid peroxidation were significantly greater in SD than in MD and WW leaves. It is speculated that vacuolar phenylpropanoids may constitute a secondary antioxidant system, even on a temporal basis, activated upon the depletion of primary antioxidant defences, and aimed at keeping whole-cell H2O2 within a sub-lethal concentration range.

The influence of tuber mineral element composition as a function of geographical location on acrylamide formation in different Italian potato genotypes.

BACKGROUND: The present study was aimed at examining the effect of tuber mineral composition, distinctive for geographical location, on the expression of acrylamide precursors in three potato genotypes (Arinda, Rossa di Cetica and Sieglinde) in three Italian potato cultivation regions (Puglia, Sicily and Tuscany). RESULTS: Sucrose and amino acids were not correlated with acrylamide formation. In contrast, reducing sugars, limiting with respect to the principal amino acid precursor asparagine, were positively correlated with acrylamide. From analysis of variance, both acrylamide and reducing sugars were not significant for variety but highly significant for location, with higher levels occurring in all three varieties cultivated in Tuscany, followed by Sicily and Puglia respectively. Reducing sugars were negatively correlated with K and Ca and positively correlated with Zn and Cu. Neither N nor P was correlated with reducing sugar content. Path analysis, a statistical technique distinguishing causation and correlation between variables, was implemented to provide additional insight on the interactions between mineral elements and reducing sugars under open field conditions. The variation in reducing sugars in all three varieties was shown to be attributable to Zn. CONCLUSION: Cultivation location has a significant impact on the composition of tuber mineral elements and, as a result, on genotype in the expression of reducing sugars. The negative correlation between Zn and K and the variation in reducing sugar content attributed to the element Zn, which is particularly available in acid soils, are important factors warranting future research aimed at reducing acrylamide formation from an agronomic perspective.

Chemical composition of scent-gland secretions in an old world monkey (Mandrillus sphinx): influence of sex, male status, and individual identity.

Primates are traditionally considered to be microsmatic, with decreased reliance on olfactory senses in comparison to other sensory modalities such as vision. This is particularly the case for Old World monkeys and apes (catarrhines). However, various lines of evidence suggest that chemical communication may be important in these species, including the presence of a sternal scent-gland in the mandrill. We investigated the volatile components of mandrill odor using gas chromatography-mass spectrometry. We identified a total of 97 volatile components in 88 swabs of the sternal gland secretion and 95 samples of sternal gland hair saturated with scent-gland secretion collected from 27 males and 18 females. We compared odor profiles with features of the signaler using principle components and discriminant function analyses and found that volatile profiles convey both variable (age, dominance rank in males) and fixed (sex, possibly individual identity) information about the signaler. The combination of an odor profile that signals sex, age, and rank with increased motivation to scent-mark and increased production of secretion in high-ranking males leads to a potent signal of the presence of a dominant, adult male with high testosterone levels. This may be particularly relevant in the dense Central African rain forest which mandrills inhabit. By contrast, we were unable to differentiate between either female cycle stage or female rank based on odor profiles, which accords with behavioral studies suggesting that odor signals are not as important in female mandrills as they are in males. The similarity of our findings to those for other mammals and in primates that are more distantly related to humans suggests a broader role for odor in primate communication than is currently recognized.

Determination of organic acids in urine by solid-phase microextraction and gas chromatography-ion trap tandem mass spectrometry previous 'in sample' derivatization with trimethyloxonium tetrafluoroborate.

A method for the determination of the organic acids directly in the urine employing derivatization with trimethyloxonium tetrafluoroborate as a methylating agent and sequential extraction by head space and direct immersion/solid phase microextraction is reported. Furoic acid, hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid and trans, trans muconic acid contained in urine and proposed by the American Conference of Governmental Industrial Hygienists as biological exposure indices were determined after a fast and economically convenient preparation step and sensitive gas chromatography-ion trap-mass spectrometry/tandem mass spectrometry analysis. Urine is rather a complex sample and hence the acquisition method required specific GC-MS instrumentation capable of supporting the changeover, fully automated during a single chromatographic separation, from mass to tandem mass spectrometry and both chemical and electron ionization modes. The automation of the analytical method provides a number of advantages, including reduced analysis time for both routine analysis and method development, and greater reproducibility. The equilibrium and kinetics of this substances vs head space/direct immersion-solid phase microextraction were investigated and evaluated theoretically.

Fate of prions in soil: interactions of RecPrP with organic matter of soil aggregates as revealed by LTA-PAS.

The contribution of soil organic matter (OM) to the adsorption of a recombinant prion protein (RecPrP) was studied in microcosm systems (soil aggregates from two different soils) before and after OM removal by low temperature ashing (LTA). The LTA technique allows a controlled removal of OM layer by layer, like a peeling of an onion skin, with minimal disturbance of the mineral matrix. Soil aggregates were selected as a representative model of the "in situ" conditions. Adsorption from batch vs percolation experiments were compared, and the aggregates were characterized by photoacustic Fourier-transform IR spectroscopy (PAS-FTIR). High affinity (H-type) adsorption isotherms were found with complete removal of RecPrP from solution for protein/soil ratios up to 1:62.5. OM removal from aggregates decreased the adsorbed RecPrP in amounts corresponding to 330-1000 microg mg(-1) of soil organic carbon (OC) indicating that native OM has specific adsorption capacity comparable and/or superior to the mineral matrix. The coupled LTA-PAS-FTIR approach demonstrated that, albeit OM composition was homogeneous throughout the aggregates, its presence in the most external surfaces of the aggregates affects the diffusion dynamics of RecPrP within the aggregates during percolation.

Insertion of a magnesium(II)-octacarboranyl(hexylsulfanyl) porphyrazine into liposomes: a physico-chemical study.

The synthesis, characterization and liposome insertion of a novel magnesium(II) carboranyl-porphyrazine, i.e. [2,3,7,8,12,13,17,18-octakis-(1,2-dicarba-closo-dodecaboranyl)-hexylthio-5,10,15,20-porphyrazine]magnesium(II) complex, MgHECSPz, are described. MgHECSPz was designed to improve the potentiality in multiple approach anticancer therapy. Liposomal formulations with different surface charge were prepared as delivering agents. The obtained loaded vectors were characterized by DLS, SAXS, SANS and zeta potential measurements in order to define the overall properties and structural details of loaded liposomes.

Ceramic nanomaterials from aqueous and 1,2-ethanediol supersaturated solutions at high temperature.

The aim of this study was the synthesis and physicochemical characterization of some nanosized hydroxides/oxides interesting in the field of ceramic materials with the aim of developing new materials for technological applications in the field of high-performance coatings. In particular, attention was focused on ZrO2nH2O, ZrO2, Zn(OH)2, ZnO, Al2O3nH2O, and Al2O3. The synthesis was carried out in 1,2-ethanediol at 150-160 degrees C or in water at 90 degrees C at a high degree of supersaturation in order to achieved nucleation rate much greater than the growth rate. The obtained ZrO2nH2O, Zn(OH)2, and Al2O3nH2O particles were peptized to eliminate possible agglomeration and then calcinated at a suitable temperature to allow the formation of the corresponding anhydrous oxides. The synthesized particles were characterized by scanning and transmission electron microscopy, X-ray diffractometry, and differential thermal analysis coupled with thermogravimetry and Fourier transform infrared spectroscopy. The study showed that all the products can be obtained in the nanostructured crystalline form; ZrO2 presented the interesting feature of different tetragonal/monoclinic ratios depending on the solvent used for the synthesis. Preliminary results on the potentialities of these ZrO2 particles as agents for ultrahard coatings on ceramic surfaces were encouraging and very promising.

DOTAP/DOPE and DC-Chol/DOPE lipoplexes for gene delivery: zeta potential measurements and electron spin resonance spectra.

Non-viral vectors represent an important alternative in gene delivery. Among these vectors, cationic liposomes are widely studied, because of their ability to form stable complexes with DNA fragments (lipoplexes). In the present work, we report on the characterization by electron spin resonance (ESR) spectroscopy and zeta potential measurements of cationic liposomes and of their complexes with oligonucleotides. Liposomes were made with a zwitterionic lipid, DOPE, and a cationic lipid, either DOTAP or DC-Chol. Oligonucleotides were the 20-base single strand polyA, the 20-base single strand polyT, and the corresponding double strand dsAT. The zeta potential as a function of the oligonucleotide/lipid+ ratio gave an S-shaped titration curve. Well-defined surface potential changes took place upon charge compensation between the cationic lipid heads and the phosphate groups on the oligonucleotides. The inversion point depended on the specific system under study. The bilayer properties and the changes that occurred with the incorporation of DNA fragments were also monitored by ESR spectroscopy of appropriately tailored spin probes. For all the systems investigated, the ESR spectra showed that no major alteration took place after lipoplex formation and molecular packing remained substantially unchanged. Both zeta potential and ESR measurements were in favor of an external mode of packing of the lipoplexes.