Studies on umami taste. Synthesis of new guanosine 5'-phosphate derivatives and their synergistic effect with monosodium glutamate

A number of N2-alkyl and N2-acyl derivatives of guanosine 5'-phosphate (GMP) have been synthesized and tested for their synergistic effect with monosodium L-glutamate (MSG), the prototypical substance imparting umami taste to savory-based foods. Capacities to enhance the taste intensity of MSG (gamma values) were estimated through subjective comparisons of MSG/nucleotide mixtures in water with appropriate solutions of MSG alone. Assuming beta = gamma[nucleotide]/gamma[IMP], beta values of the N2-substituted GMPs were found in the range 1.2-5.7. Such values appear to be related to the chain length of the substituent in the 2-position of the purine nucleus and dependent on the replacement of a CH 2 group with an S atom and/or with an alpha-CO group. These findings indicate that the exocyclic NHR group of the guanine moiety is actively implicated in the synergism between GMP derivatives and MSG. Theoretical calculations suggest that an anti conformation is probably assumed by ribonucleotide molecules interacting with umami receptors.     

Terrestrial-marine continuum of sedimentary natural organic matter in a mid-latitude estuarine system

Journal of Soils and Sediments - Humic acids (HA) have several environmental roles, but are particularly important in aquatic environments, being recognized as redox active natural organic matter...     

Effect of feeding intensity and milking system on nutritionally relevant milk components in dairy farming systems in the North East of England

There is increasing concern that the intensification of dairy production reduces the concentrations of nutritionally desirable compounds in milk. This study therefore compared important quality parameters (protein and fatty acid profiles; α-tocopherol and carotenoid concentrations) in milk from four dairy systems with contrasting production intensities (in terms of feeding regimens and milking systems). The concentrations of several nutritionally desirable compounds (β-lactoglobulin, omega-3 fatty acids, omega-3/omega-6 ratio, conjugated linoleic acid c9t11, and/or carotenoids) decreased with increasing feeding intensity (organic outdoor ≥ conventional outdoor ≥ conventional indoors). Milking system intensification (use of robotic milking parlors) had a more limited effect on milk composition, but increased mastitis incidence. Multivariate analyses indicated that differences in milk quality were mainly linked to contrasting feeding regimens and that milking system and breed choice also contributed to differences in milk composition between production systems.     

Simultaneous determination of clofentezine,fenoxycarb and hexythiazox by HPLC on apples,pears and their pulps

The simultaneous HPLC determination of clofentezine, fenoxycarb and hexythiazox in apples, pears and their pulps is described. The method is based on a clean-up procedure carried out on a Seppak C18 cartridge followed by HPLC analysis on an RP-18 column using acetonitrile + water as mobile phase. Average recoveries were 85.0% for clofentezine, 84.8% for fenoxycarb and 75.6% for hexythiazox on apple matrix; recoveries from pear matrix were in the same range. UV detection limits at 240 nm were 0.07 mg kg^?1 for clofentezine, 0.064 mg kg^?1 for fenoxycarb and 0.08 mg kg^?1 for hexythiazox.     

In vitro formation of metabolic-intermediate cytochrome P450 complexes in rabbit liver microsomes by tiamulin and various macrolides

Tiamulin and a number of macrolides were evaluated as to their ability in forming metabolic-intermediate (MI) complexes with cytochrome P450 in liver microsomes from rabbits bred for meat production. Complex formation, which occurred only in preparations where the expression of P450 3A was increased as the result of rifampicin pre-treatment and with different kinetics, was in the order tiamulin > erythromycin > TAO approximately roxithromycin approximately tylosin and did not take place with tilmicosin and spiramycin. Most of the tested compounds underwent an oxidative N-dealkylation and a good relationship could be found between the rate of N-dealkylase activity in induced preparations and the aptitude in generating MI complexes. Although the results from in vitro studies should be interpreted with caution, it is suggested that the potential for in vivo drug interactions also exists in the rabbit for tiamulin and for four out of the six tested macrolides.     

Multiple-center study of reduced-concentration triamcinolone topical solution for the treatment of dogs with known or suspected allergic pruritus

OBJECTIVE: To determine the efficacy of triamcinolone acetonide topical solution (TTS) in dogs for use in reduction of clinical signs of pruritic inflammatory skin diseases of a known or suspected allergic basis and to evaluate adverse effects associated with TTS administration. ANIMALS: 103 pruritic adult dogs with known or suspected allergic skin disease. PROCEDURE: Dogs were treated for 4 weeks with TTS or with vehicle solution (control dogs) in a multiple-center study. Clinical signs were scored by owners and by examining veterinarians before and after treatment. Blood samples obtained before and after treatment were subjected to routine hematologic and serum biochemical analyses. RESULTS: Treatment success, as defined by an improvement of at least 2 of 6 grades in overall clinical score, was evident in 35 of 52 (67%) TTS-treated dogs (mean improvement, 1.98) and 12 of 51 (24%) control dogs (mean improvement, 0.29). For several criteria, TTS was significantly more effective than vehicle in reducing clinical signs. Minor alterations in hematologic determinations in TTS-treated dogs were limited to slightly lower total leukocyte, lymphocyte, and eosinophil counts after treatment. Minor adverse effects were reported by owners in 6 of 52 (12%) TTS-treated and 9 of 51 (18%) control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Triamcinolone used as a spray solution at a concentration approximately one-sixth the concentration of triamcinolone topical preparations currently available for veterinary use is effective for short-term alleviation of allergic pruritus in dogs. Adverse effects are few and mild and, thus, do not preclude prolonged treatment with the solution.     

Characterization and degradation of lignin from steam explosion of pine and corn stalk of lignin: The role of superoxide ion and ozone

Steam explosion of corn stalk in the presence of 3% sulphuric acid at 200 °C for 5 min gave the highest recovery of lignin. Lignin has M_w = 2640 and M_z = 93,994. In the UV spectrum absorptions at λ = 231 and 280 nm were recorded. ¹H NMR spectrum of lignin showed signals attributable to cinnamaldehyde units, guaiacyl units, and syringyl units. Syringyl and guaiacyl units are in 1:1 ratio. ¹³C NMR spectrum showed signals for guaiacyl, syringyl, and p-hydroxyphenyl units. The spectrum showed a prevalence of guaiacyl units. The ¹³C NMR spectrum is in agreement with the presence of cinnamic units. The same characterization was performed on lignin from pine. The irradiation of lignin from pine from steam explosion process in the presence of oxygen, in conditions described for the formation of superoxide ion, for different irradiation time was followed isolating the lignin and determining the average molecular weight. The experiments showed that, until 8 h irradiation, M_n decreases, while M_w and M_z increases. After 8 h irradiation an inverse behaviour was observed, with an increase of M_n and a decrease of M_w and M_z. These results are in agreement with an initial polymerization process followed by a photoinduced degradation. Ozonization was carried out in acetonitrile–methanol solution. The reaction showed a zero-order kinetics. After 50 min the average molecular weight of lignin is the half. The reaction mixture was analyzed by using GC–MS. Oxalic acid was determined.     

Phenological investigations of different winter-deciduous species growing under Mediterranean conditions

Phenological stages are the result of biorhythms and environmental factors, these last are probably the same ones that caused, during evolution, adjustments of the species to different climate. The present study was carried out in a Phenological Garden located in central Italy (Perugia, Umbria Region) which contains indicator species, common to all International Phenological Gardens. The aim of this study was to determine and analyse the average trends of development of eight plant species and their phenological adjustment to the Mediterranean environment, over a nine-year period (1997–2005). The results of the statistical analyses show a strong relationship between the temperature trends and vegetative seasonal evolutions interpreted by phenological data for all the species considered. Moreover, it was demonstrated that the plants studied may approach or close completely the timing gaps eventually created during the first phenological phases, adjusting thus the beginning of subsequent phenophases.     

Lipoxygenase distribution in coffee (Coffea arabica L.) berries

In this paper lipoxygenase (LOX) presence was investigated in coffee berries to determine its involvement in lipid degradative metabolism of plants grown in organic and conventional cultivations. An immunochemical analysis has evidenced a ca. 80 kDa protein, cross-reacting with an anti-LOX antibody, only in the pulp fraction of berries obtained from plants of both cultivations. LOX activity in this fraction could be monitored either as conjugated diene formation or reaction products (determined by HPLC) and was mainly associated with a heavy membrane fraction (HMF, enriched in tonoplast, endoplasmic reticulum, plasma membrane, and mitochondria) and a light membrane fraction (LMF, enriched in plasma membrane and endoplasmic reticulum, with low levels of tonoplast and mitochondria). The LOX activity of LMF from berries of both cultivations showed an optimum at pH 8.0. The HMF exhibited a different activity peak in samples from conventional (pH 8.0) and organic (pH 5.5) cultures, suggesting the presence of different isoenzymes. These findings were also confirmed by variation of the ratio of 9- and 13-hydroperoxides in organic (1:1) and conventional cultivations (1:10), indicating that the organic one was subjected to an oxidative stress in the coffee pulp fraction leading to the expression of an acidic LOX. Such de novo synthesized LOX activity could be responsible for the production of secondary metabolites, which may interfere with the organoleptic profile of coffee.     

Reconstructing the history of the sand tiger shark (Carcharias taurus) in the Mediterranean Sea

1. Sharks are globally exposed to several anthropogenic threats, which, in many cases, have severely reduced their distribution and have impacted populations. In the Mediterranean Sea, because of its long history of exploitation and the relatively short span of scientific monitoring, reconstructing shark baselines is challenging. Many vulnerable species declined in population abundance and geographic distribution before it was possible to adequately track these changes. Consequently, for many of these species, current conservation assessments are now suffering from a severe case of shifting baseline syndrome, whereby their historical occurrence in the area is questioned.
2. The sand tiger shark (Carcharias taurus) is one of these cases. Characterized by high philopatry, restricted home range, and low interchange between populations, its Mediterranean population may have been severely impacted by the high historical fishing pressure in the region before scientific monitoring began.
3. In this study, the history of the abundance and distribution of C. taurus in the Mediterranean Sea was reconstructed through a comprehensive search of occurrence records in the literature and in museum collections. Between 1810 and 2008, 31 occurrence records and 54 publications provided information on the presence of the species in the area. These records were sparse but systematic over time and indicated occurrence hot spots in the south‐western Mediterranean Sea and in the eastern Adriatic Sea.
4. The presence of ten sightings of juveniles from a total of 18 sightings with length information suggested local parturition. Habitat and extinction models indicate that the area has suitable oceanographic conditions for the occurrence of the species and that the species cannot be considered extinct in the Mediterranean Sea. Our study suggests that there is still hope for the recovery of the species and underlines the crucial role of historical investigations to reconstruct the history of large elasmobranchs in the Mediterranean Sea.