Influence of autochthonous Saccharomyces cerevisiae strains on volatile profile of Negroamaro wines

Saccharomyces cerevisiae is the yeast species predominating the alcoholic fermentation of grape must. The aim of this research was to evaluate the impact of indigenous S. cerevisiae strains biodiversity on the aroma of wines from Negroamaro grapes. Grapes collected in two different Negroamaro producing micro districts in Salento (Southern Italy), were subjected to natural fermentation and two indigenous S. cerevisiae populations were isolated. Fifteen strains for each of the two populations were selected and tested by micro fermentation assay in order to evaluate their specific contribute to the volatiles composition and sensory impact of the produced wines. The aromatic profile of wines obtained by each selected strain was characterized by different contents of acetates, ethyl esters of fatty acids, higher alcohols, thus showing to be related to the strains geographical origin. The sensorial analysis of wines produced by the six best performing strains confirmed that they are good candidates as industrial starter cultures, This study indicates that the use of a “microarea-specific” starter culture is a powerful tool to enhance the peculiarity of wines deriving from specific areas.     

The emerging role of cytochrome P450 3A in psychopharmacology

Recent advances in molecular pharmacology have allowed the characterization of the specific isoforms that mediate the metabolism of various medications. This information can be integrated with older clinical observations to begin to develop specific mechanistic and predictive models of psychotropic drug interactions. The polymorphic cytochrome P450 2D6 has gained much attention, because competition for this isoform is responsible for serotonin reuptake inhibitor-induced increases in tricyclic antidepressant concentrations in plasma. However, the cytochrome P450 3A subfamily and the 3A3 and 3A4 isoforms (CYP3A3/4) in particular are becoming increasingly important in psychopharmacology as a result of their central involvement in the metabolism of a wide range of steroids and medications, including antidepressants, benzodiazepines, calcium channel blockers, and carbamazepine. The inhibition of CYP3A3/4 by medications such as certain newer antidepressants, calcium channel blockers, and antibiotics can increase the concentrations of CYP3A3/4 substrates, yielding toxicity. The induction of CYP3A3/4 by medications such as carbamazepine can decrease the concentrations of CYP3A3/4 substrates, yielding inefficiency. Thus, knowledge of the substrates, inhibitors, and inducers of CYP3A3/ and other cytochrome P450 isoforms may help clinicians to anticipate and avoid pharmacokinetic drug interactions and improve rational prescribing practices.     

Neural networks applied to a large biological database to analyse dairy breeding patterns

The paper recounts the investigation of a dairy sire prediction capability based on Cascade Correlation neural networks to study influences relating the performance of offspring to their parents. The context of the problem is the artificial insemination breeding program for the Australian dairy industry. The networks are used to screen observed information in the database to relate it to best combinations of dam and sire. The voluminous data is quite noisy and is subject to genetic and environmental influences. The intention is to extract linear and nonlinear relationships from among the input variables without specifying their form. A number of scenarios are employed which recast the data into different forms. In particular, it was discovered that the problem could be restructured and the data supplemented with transformed data to produce succinct input patterns of manageable dimensionality, which allowed for a substantially improved predictive capability. It was then found that reasonable daughter predictions could be obtained of about 10%, as measured by her milk production. Results are compared with those obtained using two alternate neural network methods. Crude statistical methods are employed to evaluate the performance of the neural networks.     

Oxidation at boron doped diamond electrodes: an effective method to mineralise triazines

The electrochemical oxidation of cyanuric acid (CA) is examined by bulk electrolyses at boron doped diamond (BDD) electrode. The influence of operating conditions on the reaction trend is investigated and suitable conditions for oxidative demolition of CA are individuated. In particular a strong effect of current density and pH is evidenced, being neutral pH and high current the most favourable conditions to achieve CA mineralisation. The paper also presents the results from atrazine (2-Cl-4-ethylamino-6-isopropylamino-1,3,5-triazine) and 2-Cl-4,6-diammino-1,3,5-triazine oxidation at BDD anode. Triazine compounds are scarcely degraded even with powerful methods such as photocatalytic TiO₂-mediated processes, being CA generally obtained as final product of their oxidation. Individuation of favourable conditions for CA demolition has allowed to find suitable conditions to mineralise also triazine compounds.     

Kinetics of the electrochemical oxidation of organic compounds at BDD anodes: modelling of surface reactions

This paper presents the results of a numerical study of the kinetics of electrochemical oxidation of different organic substances at boron doped diamond (BDD). It is well established that oxidation of organics at BDD anodes takes place in the potential region of oxygen evolution, through reaction steps in which OH radicals are involved: these radicals can react with organic compounds to give more oxidised substances, or with water to give oxygen. Because of the high reactivity of OH radicals these reactions are confined to a thin film adjacent to the electrode surface. A mathematical model was implemented, which accounts for chemical and electrochemical reactions, as well as for the transport phenomena involved in the process: the parameters of the model were derived from experimental data. The model allowed calculation of the trend with time of reactant concentration, reaction intermediates and oxidisable agents: their space profiles in the reactor were also obtained. The numerical predictions of the model were compared with experimental results obtained from galvanostatic electrolyses of different organic compounds: (a) 2,4,6-trihydroxy-1,3,5 triazine also known as cyanuric acid (CA), which is well known to be refractory to oxidation with OH; (b) atrazine (ATR) the most oxidisable precursor of CA, and (c) phenol which is considered as an OH scavenger because of its high reactivity. The agreement between experimental and model predicted data was good in all the examined conditions.     

Umbelliferone aminoalkyl derivatives as inhibitors of oxidosqualene cyclases from <Emphasis Type="Italic">Saccharomyces cerevisiae,Tripanosoma cruzi</Emphasis>, and <Emphasis Type="Italic">Pneumocystis carinii</Emphasis>

A series of umbelliferone aminoalkyl derivatives, previously studied as inhibitors of squalene-hopene cyclase, were tested as inhibitors of yeast (Saccharomyces cerevisiae) oxidosqualene cyclase (OSC) and OSC from Trypanosoma cruzi and Pneumocystis carinii expressed in yeast. Enzymes from these pathogens were included in this study to provide a preliminary screening for antiparasitic activity. Tests were carried out both on cell homogenates incubated with radiolabeled oxidosqualene and on spheroplasts incubated with radiolabeled acetate. Derivatives bearing a methylallylamino group were the most effective on all of the three enzymes. The P. carinii enzyme was the most susceptible to the action of the inhibitors, with IC₅₀ values for almost all of them ranging from 0.1 to 1μM. The T. cruzi enzyme was appreciably inhibited (IC₅₀ 4–5 μM) only by derivatives bearing a methylallylaminoalkyl flexible chain. Results identify a particularly promising new family of OSC inhibitors, for the development of novel antiparasitic agents.     

Regulation of HMGCoA Reductase Activity by Policosanol and Octacosadienol,a New Synthetic Analogue of Octacosanol

Octacosa-10,19-dien-1-ol is a newly synthesized long-chain alcohol, an unsaturated analogue of 1-octacosanol, the major component of policosanol, the purified natural mixture of different higher aliphatic alcohols obtained from sugarcane wax. Our efficient synthetic protocol (five steps with 50% overall yield) is well suited for gram scale preparations and a rapid generation of analogues with different degrees of unsaturation. Beneficial effects of policosanol in the prevention of atherosclerosis and thromboembolic disorders have been reported and related to the inhibition of sterol biosynthesis possibly by the regulation of the activity of HMGCoA reductase mediated by AMP-dependent kinase AMPK. We have compared the effect of octacosadienol and policosanol on the regulation of HMGCoA reductase in HUVEC and HepG2 human hepatoma cells. Octacosadienol was as effective as policosanol in inhibiting the upregulation of HMGCoA reductase, in inducing the phosphorylation of AMPK and in downregulating the HMGCoA reductase mRNA.     

A study on relationships between durum wheat semolina properties,technological mixing parameters and the properties of dough after mixing

Partial least square regression analysis was used to study the correlation between X variables (semolina quality, hydration level and mixing time) and Y variables, which were, in a first model, dough consistency during mixing, and, in a second model, dough properties after mixing (strength, elasticity, density) and leavening (maximum volume). The first model showed a predictive residual sum of squares (PRESS) of 2.98 and a predictive R² (Q²) of 0.92, and highlighted the key role of hydration and mixing time on dough consistency. The second model had the best PRESS (8.25) and Q² (0.94) values for dough volume and indicated that the volume increased with increasing mixing time until the dough consistency decreased of 20–30%. Dough volume was primarily affected by hydration. The model indicated that maximum volume after leavening, corresponding to optimum mixing time, was obtained with a soft and elastic dough, with a low‐density value.     

The dynamics of phenolic concentration in some pasture species and implications for animal husbandry

BACKGROUND: Although secondary metabolites have often been studied considering their primary role as plant‐defensive and their effect on consumers detrimental, their effects are usually dose‐dependent, so it is important to consider their content at all phenological phases and in different plant organs. In this study the content of total phenolics (TotP), non‐tannic phenolics (NTP) and proanthocyanidins (PA) was determined in natural populations of pasture species at defined phenological phases and in different plant organs and also in pathogen‐infected plants. RESULTS: Variation in TotP, NTP and PA content was observed in all species, phenological phases and plant organs. Leaf blades were the organs with the highest content in all species. The content of all examined compounds increased in infected leaves, reaching the maximum when 20% of plant tissues were attacked and decreasing at higher infection levels. CONCLUSION: Delphinidin was found as an appropriate standard related to the PA structure of each plant species. PA concentrations were always in the range considered beneficial for animals, not exceeding 60 g delphinidin equivalent kg^?1 dry matter. The Folin–Ciocalteu and butanol/HCl/Fe³⁺ assays remain the most practical methods for screening large numbers of different plant species for TotP and PA. Copyright © 2010 Society of Chemical Industry