Monitoring the effect of high pressure and transglutaminase treatment of milk on the evolution of flavour compounds during lactic acid fermentation using PTR-ToF-MS

In this study, the effects of thermal or high hydrostatic pressure (HHP) treatment of a milk base in the absence or presence of a transglutaminase (TGase) protein cross-linking step on the flavour development of yoghurt were investigated. The presence of several tentatively identified volatile flavour compounds (VOCs), both during the enzymatic treatment and the lactic acid fermentation of the milk base, were monitored using a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS). The formation of the major flavour compounds (acetaldehyde, diacetyl, acetoin, and 2-butanone) followed a sigmoidal trend described by the modified Gompertz model. The HHP treatment of milk increased significantly the volatile compound formation rate whereas it did not affect the duration of the lag phase of formation, with the exception of acetaldehyde and diacetyl formation. On the contrary, the TGase cross-linking of milk did not significantly modify the formation rate of the volatile compounds but shortened the duration of the lag phase of their formation.     

Attractivity and social preferences in mice (Mus musculus domesticus): The role of prepubertal sexual segregation and of precocious weaning.

Mice (Mus musculus domesticus) were raised (Postnatal Day 15 to 25) in single- or mixed-sex litters and precociously (Day 15) or regularly (Day 25) weaned. When they were faced as adults with a basic social choice—between two stimulus mice raised in litters of different sex composition but both of the same sex as the chooser—mice raised in mixed-sex litters were preferred. In the sociosexual choice—between a male and a female, both from the single- or the mixed-sex group—the opposite-sex preference was expressed. Both these preferences were abolished by the sexual segregation of the choosers. This variable hardly affected potential mate choice—between two stimulus mice both of the opposite sex of the chooser but raised in litters of different sex composition. Data indicate that socially mediated behavioral plasticity has a major role in the early shaping of adult individual differences both in attractive stimulus properties and in sociosexual preferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New material for orthopedic implants: Electrochemical study of nickel free P558 stainless steel in minimum essential medium

Nickel, a component of stainless steels (SS) applied in orthopedic implants may cause allergic processes in human tissues. P558 nickel free SS was studied to verify its viability as a substitute for stainless steel containing nickel. Its performance is compared to ISO 5832-9 and F138 most used nowadays grades in implants fabrications, in minimum essential medium, MEM, at 37 °C. Potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and “in vitro” cytotoxicity were used as techniques. From the electrochemical point of view P558 SS is comparable to ISO 5832-9 SS in MEM. It remains passivated until the transpassivation potential, above which generalized corrosion occurs. F138 presents pitting corrosion at 370 mV/SCE. The cytotoxicity results showed that P558, ISO 5832-9 and F138 do not present cytotoxic character. Therefore, these results suggest that P558 SS can be applied in orthopedic implants.     

Identification of four amino acid residues essential for catalysis in human cytidine deaminase by site-directed mutagenesis and chemical modifications

By site-directed mutagenesis on human cytidine deaminase (CDA), five mutant proteins were obtained: C65A, C99A, C102A, E67D and E67Q. The three cysteine mutants were completely inactive, whereas E67D and E67Q showed a specific activity about 200- and 200000-fold lower, respectively, than the wild-type CDA. Zinc analysis revealed that only E67D, E67Q and C65A contained 1 mol Zn2+/mol subunit as in the wild- type CDA. Kinetic measurements with the specific carboxylic group reagent N-ethoxy-carbonyl-2-ethoxy-1,2-dihydroquinoline performed on wild-type CDA suggest that Glu67 is essential for the catalytic process. Furthermore, when both native and denatured CDA was titrated with 5,5'-dithiobis(2-nitrobenzoic acid) six sulfhydryl groups were detected, whereas in the denatured and reduced enzyme nine such groups were found, according to the sequence data. When p-hydroxymercuriphenyl sulfonate was used, nine sulfhydryl groups were detectable and the release of 1 mol of zinc per mole of CDA subunit was revealed by the metal indicator dye 4-(2-pyridylazo)resorcinol. It seems plausible that the limiting step for the maintenance of zinc in the active site is the formation of coordination between Cys99 and Cys102, whereas Cys65 could lead the zinc to the correct position and orientation within the active site.      

Magnesium fertilization has a greater impact on soil and leaf nutrient concentrations than nitrogen or calcium fertilization in Florida orange production

Nutrient Cycling in Agroecosystems - Citrus production has been declining in Florida since 2004, mainly because of Huanglongbing (HLB), a deadly disease that is affecting an increasingly large...     

Films made from polyethylene‐co‐acrylic acid and soluble biopolymers sourced from agricultural and municipal biowaste

Blends were obtained from polyethylene‐co‐acrylic acid (PEAA) with 248 kDa molecular weight and two water soluble biopolymers isolated from the hydrolysate of postharvest tomato plant and urban biowaste compost. The two hydrolysates were constituted respectively from a polysaccharide (SP) with 27 kDa molecular weight and a lignin‐like polymer (LP) with 75 kDa molecular weight containing aliphatic and aromatic C moieties substituted by carboxyl, hydroxyl, and amino groups. Evidence was obtained for reactions occurring between the biopolymers and the synthetic polymer leading to new polymers with 151 to 1243 kDa molecular weights. The thermal and mechanical properties of the blends were studied. Compared with neat PEAA, the PEAA‐LP blends containing 5 to 10% LP exhibited 2 to 5× higher molecular weights, 10 to 50% lower crystallinity, 2 to 6× higher Young's modulus, over 3× higher stress at yield point and somewhat lower strain at break (55–280% vs. over 300%). On the contrary the PEAA‐SP blends exhibited 6 to 13% lower crystallinity and the same mechanical properties as neat PEAA. The results offer scope for investigating biopolymers sourced from other biowastes to understand more the reasons of the observed effects and exploit their full potential to modify or to replace synthetic polymers. Perspectives of economic and environmental benefits are discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41909.     

Single-crystal organic charge-transfer interfaces probed using Schottky-gated heterostructures

Organic semiconductors based on small conjugated molecules generally behave as insulators when undoped, but the heterointerfaces of two such materials can show electrical conductivity as large as in a metal. Although charge transfer is commonly invoked to explain the phenomenon, the details of the process and the nature of the interfacial charge carriers remain largely unexplored. Here we use Schottky-gated heterostructures to probe the conducting layer at the interface between rubrene and PDIF-CN(2) single crystals. Gate-modulated conductivity measurements demonstrate that interfacial transport is due to electrons, whose mobility exhibits band-like behaviour from room temperature to ~150 K, and remains as high as ~1 cm(2) V(-1) s(-1) at 30 K for the best devices. The electron density decreases linearly with decreasing temperature, an observation that can be explained quantitatively on the basis of the heterostructure band diagram. These results elucidate the electronic structure of rubrene/PDIF-CN(2) interfaces and show the potential of Schottky-gated organic heterostructures for the investigation of transport in molecular semiconductors.     

Neuroprotective Effects of Citicoline in in Vitro Models of Retinal Neurodegeneration

In recent years, citicoline has been the object of remarkable interest as a possible neuroprotectant. The aim of this study was to investigate if citicoline affected cell survival in primary retinal cultures and if it exerted neuroprotective activity in conditions modeling retinal neurodegeneration. Primary retinal cultures, obtained from rat embryos, were first treated with increasing concentrations of citicoline (up to 1000 μM) and analyzed in terms of apoptosis and caspase activation and characterized by immunocytochemistry to identify neuronal and glial cells. Subsequently, excitotoxic concentration of glutamate or High Glucose-containing cell culture medium (HG) was administered as well-known conditions modeling neurodegeneration. Glutamate or HG treatments were performed in the presence or not of citicoline. Neuronal degeneration was evaluated in terms of apoptosis and loss of synapses. The results showed that citicoline did not cause any damage to the retinal neuroglial population up to 1000 μM. At the concentration of 100 μM, it was able to counteract neuronal cell damage both in glutamate- and HG-treated retinal cultures by decreasing proapoptotic effects and contrasting synapse loss. These data confirm that citicoline can efficiently exert a neuroprotective activity. In addition, the results suggest that primary retinal cultures, under conditions inducing neurodegeneration, may represent a useful system to investigate citicoline neuroprotective mechanisms.     

Evolution of some physicochemical parameters of iodine fortified sunflower oil and margarine

Experimental research were effectuated to establish the modalities of incorporation of the molecular iodine in sunflower oil double refined and deodorised of autochthon production. It was established that the iodisation of sunflower oil may be considered as an admissible method, which allows the incorporation of a considerable amount of iodine (1–100 μg mL^?1) without modifying the physicochemical properties of the product. It should be noted that iodine value varied a little, even in the sample with a maximum content of iodine (1000 μg mL^?1), its values did not exceed permitted limit. Research of quality indices variation of iodised oil during product storage (3 months), demonstrated that only in the case of maximum concentration of iodine (1000 μg mL^?1) it was manifested a slight overcome of the maximum permitted limit caused by the free iodine presence. Iodised oil was used for the manufacture of iodised margarine in order to fortificate this product with iodine (1 μg iodine g^?1 margarine). Physicochemical indices (moisture and volatile substances, melting point, free fatty acids content) of iodised margarine did not differ from the characteristics of the product without iodine.