Studies on the Glutathione-Dehydroascorbate Oxidoreductase (EC 1.8.5.1) from Wheat Flour

Glutathione (GSH) dehydrogenase was partially purified from wheat flour after extraction, ammonium sulfate precipitation, and ionic-exchange chromatography on diethylaminoethyl (DEAE) Sepharose CL6B. Kinetic studies showed that the optimum pH was close to 7.5. The K_m values varied between 0.15 and 0.28 mM for dehydroascorbic acid (DHA) and between 1.8 and 0.62 mM for GSH when pH was varied from 5.5 to 7.5. The kinetic pattern was consistent with a sequential mechanism for the binding of GSH and DHA. NaCl is a competitive inhibitor with respect to GSH and is uncompetitive with respect to DHA, which suggests that the enzyme combines with DHA before it does with GSH. IsoDHA can replace DHA as hydrogen acceptor but with a K_m of 1.2 mM. γ-Glu-cys was enzymically oxidized but much less efficiently than GSH (V_m = 47 nkat/mL and K_m = 5.5 mM compared to V_m = 362 nkat/mL and K_m = 1.8 mM for GSH), whereas cysteine and cys-gly were not substrates. In the presence of DHA, addition of cysteine and cys-gly to small amounts of GSH causes a large activation of the enzymatic formation of ascorbic acid suggesting coupled oxidation of these thiols.     

Where land meets sea: Intertidal areas as key-habitats for sharks and rays

Intertidal habitats (i.e. marine habitats that are (partially) exposed during low tide) have traditionally been studied from a shorebird-centred perspective. We show that these habitats are accessible and important to marine predators such as elasmobranchs (i.e. sharks and rays). Our synthesis shows that at least 43 shark and 45 ray species, of which 54.5% are currently threatened, use intertidal habitats. Elasmobranchs use intertidal habitats mostly for feeding and as refugia, but also for parturition and thermoregulation. However, the motivation of intertidal habitat use remains unclear due to limitations to observe elasmobranch behaviour in these dynamic habitats. We argue that elasmobranch predators can play an important role in intertidal food webs by feeding on shared resources during high tide (i.e. ‘high-tide predators’), which are accessible and also consumed by terrestrial or avian predators during low tide (i.e. ‘low-tide predators’). In addition, elasmobranchs are able to change the bio-geomorphology of intertidal habitats by increasing habitat heterogeneity due to feeding activities and may also alter resource availability for other consumers. We discuss how the ecological role of elasmobranchs in intertidal habitats is being affected by the continued overexploitation of these species, and conversely, how the global loss of intertidal areas poses an additional threat to an already vulnerable taxonomic group. We conclude that studies on intertidal ecology should include both low-tide (e.g. shorebirds) and high-tide (e.g. elasmobranchs) predatory guilds and their ecological interactions. The global loss of elasmobranch predatory species and intertidal habitat provides additional compelling arguments for the conservation of these areas.     

Antioxidant Capacity Analysis of Blackberry Extracts with Different Phytochemical Compositions and Optimization of their Ultrasound Assisted Extraction

High antioxidant capacity molecules, such as anthocyanins, occur naturally in blackberry (Rubus fruticosus). In particular, ‘Dasha’ blackberry cultivar has scarcely been studied and, it is becoming economically more important in Mexico. In this study, several blackberry extraction conditions, conferred different amounts of detectable phytochemical groups that in turn were analysed with a new approach to investigate their influence on antioxidant capacity (AC). Additionally, a central composite design (CCD) was proposed to study effects of temperature and acidification on AC. Finally, an original approach was used to disclose interactions between the phytochemical content and the AC. Changes in size of the particles during extraction were reported for the first time, and the results showed evidence of swelling and dissolving of particles. UAE of fine and thick powders achieved similar efficiencies in contrast with maceration which showed large differences for the extraction of the tested sizes. CCD showed that low levels of acidification and high levels of temperature resulted in higher extraction of phytochemicals and AC. HPLC show that the main anthocyanidin may represent 88% of the total anthocyanins. Due to its relatively high abundance, cyanidyn-3-glucoside showed evidence of being the main cause of the changes in AC in ‘Dasha’ extracts. The use of mild conditions resulted in no degradation of anthocyanins and, therefore, there are no AC losses. A correlation plane was proposed to study synergisms of the extracts with other anthocyanins or phenolics.     

Factors influencing half‐pearl (mabe) production and quality in the red abalone Haliotis rufescens

The factors influencing half‐pearl (mabe) production in the red abalone Haliotis rufescens were investigated, as a strategy to optimize the technology for the development of a pearling industry in Chile. The effects of abalone size (small, large), implant position (dorsal, central, ventral and their combinations), and number of nuclei (one, two, three) were analysed on the quantity, thickness of the nacre layer and quality (shape, colour, lustre, defects) of the mabe produced. The size of abalone did not exert a clear influence on the quantity and quality of mabe, but the position on the shell (firstly) and number of nuclei (secondly) did. More mabe, with thicker nacre, brighter lustre and fewer defects occurred in small or large abalone implanted with only one nucleus on dorsal position. In contrast, small and large abalone implanted in the ventral position formed less mabe, with thinner nacre, poor lustre and more defects. This likely occurs because mantle tissue folds at the ventral position and does not always cover the nucleus, leaving it partially or totally exposed. Most of the pearls were categories AA in small abalone and A in large abalone; only three AAA gems were produced in large abalone with one nucleus on dorsal position or with three nuclei (DCV). Based on these results, we recommend implanting abalone at 60–100 mm shell length, with only one nucleus on the dorsal position.     

Self-assembled pullulan-silica oxygen barrier hybrid coatings for food packaging applications

The scope of this study encompassed the evaluation of pullulan as a suitable biopolymer for the development of oxygen barrier coatings to be applied on poly(ethylene terephthalate) (PET), especially for food packaging applications. To enhance the oxygen barrier properties of the organic phase (pullulan) even at high relative humidity values, an inorganic phase (silica), obtained through in situ polymerization, was also utilized to obtain hybrid coatings via the sol-gel technique. Transmission electron microscopy (TEM) images and Fourier transform infrared (FT-IR) spectra showed that mixing the two phases yielded a three-dimensional hybrid network formed by self-assembly and mediated by the occurrence of new hydrogen-bond interactions at the intermolecular level, although the formation of new covalent bonds could not be excluded. The deposition of the hybrid coatings decreased the oxygen transmission rate (OTR) of the plastic substrate by up to 2 orders of magnitude under dry conditions. The best performance throughout the scanned humidity range (0%-80% relative humidity) was obtained for the formulation with the lowest amount of silica (that is, an organic/inorganic ratio equal to 3).     

Assessing the Oxidative Stress Induced by Paracetamol Spiked in Artificial Sediment on Hyalella azteca

Paracetamol is an antipyretic analgesic widely used globally. It has been recurrently found in water bodies and is known to elicit toxic effects in aquatic species; however, its potential ability to induce oxidative stress in sentinel species remains unknown The objective was to establish a methodology to evaluate the toxicity elicited on the sentinel species Hyalella azteca by paracetamol-enriched sediment using oxidative stress tests. Concentrations used in assays were determined using the previously obtained median lethal concentration (72?h LC₅₀). The following oxidative stress biomarkers were evaluated: lipid peroxidation (LPO), protein carbonyl content (PCC) in order to determine oxidized protein content, and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX). LPO and PCC increased significantly while SOD, CAT, and GPX decreased significantly (p?<?0.05) with respect to controls. Paracetamol induces oxidative stress on H. azteca, and the set of tests employed is helpful in evaluating the toxicity of this group of pharmaceuticals on aquatic species.     

Alginate oligosaccharides preparation,biological activities and their application in livestock and poultry

Alginate oligosaccharides(AOS), belonging to the class of functional marine oligosaccharides, are low-molecular polymers linked by β-1,4-mannuronic acid(M) and α-1,4-guluronic acid(G), which could be classically obtained by enzymatic hydrolysis of alginate. With low viscosity and good water solubility, as well as anti-oxidant, immune regulation, anti-bacterial and antiinflammatory activities, AOS have been widely used in medical science and functional food, green agriculture and other fields. As new bio-feed additives, AOS have broad potential applications in animal husbandry. In this review, the sources of alginate, chemical structure and preparation methods of AOS, and their biological activities and application in livestock and poultry are summarized. We expect this review could contribute to lay a foundation of application and further research for AOS in livestock and poultry.     

Phenols content and 2-D electrophoresis protein pattern: a promising tool to monitor <Emphasis Type="Italic">Posidonia</Emphasis> meadows health state

Background  

The endemic seagrass Posidonia oceanica (L.) Delile colonizes soft bottoms producing highly productive meadows that play a crucial role in coastal ecosystems dynamics. Human activities and natural events are responsible for a widespread meadows regression; to date the identification of "diagnostic" tools to monitor conservation status is a critical issue. In this study the feasibility of a novel tool to evaluate ecological impacts on Posidonia meadows has been tested. Quantification of a putative stress indicator, i.e. phenols content, has been coupled to 2-D electrophoretic protein analysis of rhizome samples.     

Treatment of hydrocephalus with ventriculoperitoneal shunting in twelve dogs

Objective: To report use of ventriculoperitoneal shunt in dogs for management of hydrocephalus for which no cause could be identified. Study Design: Case series. Animals: Dogs with hydrocephalus (n=12). Methods: Medical records (June 2003–June 2009) were reviewed to determine preoperative clinical findings, initial postoperative, and long‐term outcome. Additional follow‐up information was obtained from owners and referring veterinarians. Results: All dogs had signs of forebrain dysfunction, 7 had vestibular signs and 3 had signs of spinal pain. Postoperative complications included pain (n=4), undershunting because of shunt kinking (n=1) and seizures (n=1). Initial improvement occurred in all dogs and was sustained in 9 dogs, 1 of which required revision surgery. Conclusions: Sustained clinical improvement can be achieved in hydrocephalus with no active underlying cause by use of ventriculoperitoneal shunting.     

Efficacy of a novel combination of fipronil, amitraz and (S)-methoprene for treatment and control of tick species infesting dogs in Europe

Four studies were conducted to show the effectiveness of a novel combination of fipronil, amitraz and (S)-methoprene in a spot-on formulation (CERTIFECT?, Merial Limited, GA, USA) for the therapeutic and preventive control of Ixodid tick species affecting dogs in Europe: Ixodes ricinus, Dermacentor reticulatus and Rhipicephalus sanguineus. In each, untreated control dogs were compared to others treated with the novel combination. All dogs were infested with 50 adult, unfed ticks prior to treatment and at 7-day intervals after treatment. Ticks on all dogs were counted at 18, 24 and 48 h after treatment (therapeutic efficacy) or infestation (preventive efficacy). Therapeutic efficacy of fipronil, amitraz and (S)-methoprene was excellent as shown by significant (p<0.05) and greater than 97% and up to 100% reductions in the 48 h tick counts and significant (p<0.05) detachment/death of ticks evident at 18-24h after treatment for all three tick species. Preventive efficacy was demonstrated by significant (p<0.05) and greater than 93% and up to 100% reductions in tick counts at 48 h after repeat infestations out to 35 days after treatment for I. ricinus and out to 42 days after treatment for D. reticulatus and R. sanguineus. The time to substantial disruption of establishment of new tick infestations after treatment was less than 18-24h and was maintained for up to 28 days after treatment of I. ricinus and D. reticulatus infestations, and 4h to at most 18 h and maintained up to 35 days after treatment of R. sanguineus. Similar preventive efficacy profiles for each of the Ixodid species tested suggest that CERTIFECT kills all Ixodid species starting 4h after contact as demonstrated for R. sanguineus.