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Surface drip fertigation has demonstrated promising results regarding the mitigation of nitrous oxide (N2O) emissions. The use of subsurface irrigation may offer the possibility of reducing these emissions further due to the modification of the soil moisture profile and N allocation, both of which affect the biochemical processes leading to N2O fluxes. However, the mitigation potential of subsurface irrigation combined with different mineral nitrogen (N) fertilizers (ammonium or nitrate-based, use of nitrification inhibitors) still needs to be evaluated. To respond to this need, a 2-year field experiment was set up in central Spain to test two different drip-fertigation systems (surface and subsurface at 30 cm depth) and four N fertilization treatments (control, calcium nitrate, and ammonium sulfate with or without the nitrification inhibitor 3,4-dimethylpyrazole phosphate, DMPP) in an irrigated maize (Zea mays L.) crop. Nitrous oxide emissions, mineral N concentrations (ammonium, NH4+, and nitrate, NO3−), and abundance of key N genes involved in nitrification and denitrification processes were measured in two soil layers (0–20 and 20–40 cm). Regardless of the irrigation system, ammonium sulfate gave the highest cumulative N2O losses in both campaigns, while calcium nitrate and the use of DMPP were the most effective strategies to abate N2O fluxes in the first and second years, respectively. Differences between irrigation systems were not statistically significant for cumulative N2O emissions, despite the clear effect on topsoil mineral N (higher NH4+ and NO3− concentrations in surface and subsurface drip, respectively). Nitrous oxide emissions were positively correlated with soil NH4+ concentrations. Gene abundances were not a trustworthy predictor of N2O losses in the 1st year, although a clear inhibitory effect of fertilization on microbial communities (i.e., ammonia oxidizers, nitrite reducers, and N2O reducers) was observed during this campaign. During the second year, nitrifying and denitrifying genes were affected by irrigation (with higher abundances in the 20–40 cm layer in subsurface than in surface drip) and by the addition of DMPP (which had a detrimental effect on gene abundances in both irrigation systems that disappeared after the fertigation period). In conclusion, the use of DMPP or calcium nitrate instead of ammonium sulfate may enhance the chances for an additional mitigation in both surface and subsurface irrigation systems. [ABSTRACT FROM AUTHOR]

The study of human remains from the perspective of forensic taphonomy facilitates a holistic understanding of ancient funerary behavior, and it is even more important when dealing with commingled assemblages. This is the case of Cova Foradada (Calafell, Spain), where more than 2500 disarticulated, fragmented, and commingled human remains, both burned and unburned, were recovered, belonging to at least 23 individuals. This study aims to reconstruct the taphonomic history of the site and identify the funerary treatments applied. Radiocarbon dating indicates the use of the cave at the beginning and end of the Neolithic, and taphonomic analysis has enabled us to differentiate a third period of funerary use. The results of this study have revealed that burned and unburned remains present in the cave constitute two different accumulations separated in time that were mixed due to multiple post-depositional agents and processes, including anthropogenic activities. The cremation pattern of the burned remains evidences the cremation of green bones, probably whole bodies, inside the cave, representing an intermediate practice between collective burials and the individual cremation characteristic of the Late Bronze Age. There is, therefore, repeated use of the same space with a sepulchral concept, from the Neolithic to the Bronze Age, but involving different funerary practices: inhumation and cremation. [ABSTRACT FROM AUTHOR]

A two-dimensional achiral-chiral LC-LC method in heart-cut mode for ketoprofen and its enantiomeric fraction determination was proposed. A C column was used in the first dimension, and the chiral column was an α-acid glycoprotein. The mobile phase of the chiral system was optimized by a factorial design. The effect of temperature on retention and on enantiomeric resolution was studied. Particular attention was paid to mobile phase compatibility for the two columns and to transferring time, using ketoprofen standards. The R-(−) and S-(+)-ketoprofen retention times were 9 and 11 min, respectively; the resolution was higher than 1.1 and enantiomeric fraction close to 0.5. The method was applied to capsules and gels containing ketoprofen. Factorial design was also used to establish the best conditions for gel sample preparation. Recoveries were 84 and 105 % for capsules and gels, respectively. [ABSTRACT FROM AUTHOR]

The effect of antioxidants applied in one step of a cryopreservation protocol by encapsulation-dehydration on recovery and genetic stability of mint shoot tips has been studied. Glutathione (0.16 or 0.24 mM), ascorbic acid (0.28 or 0.43 mM) and α-tocopherol (vitamin E) were added to the preculture medium (0.3 M sucrose). DNA was extracted from three different types of samples: leaves from shoots, callus at the base of shoots and callus. RAPD and AFLP markers were used to assess the genetic stability. The use of antioxidants did not improve recovery after cryopreservation. One of the genotypes, 'MEN 198', showed higher percentage of stable samples than the other one, 'MEN 186' (56 vs. 37 %; considering all treatments and types of explant). The use of vitamin E improved the percentage of stable samples with respect to control treatment (no antioxidant) in 'MEN 186'. No differences in the percentages of stable samples were observed among cryopreserved and non-cryopreserved (treated similarly without immersion in liquid nitrogen) plant material. Recovered shoots of both genotypes showed higher stability (76-80 % stable samples) than callus samples (14-22 %). [ABSTRACT FROM AUTHOR]

Some properties of DNA condensed with spermidine have been compared with the properties of DNA condensed with Co(NH) to determine whether condensation of DNA with these trivalent cations protects DNA against the action of DNase I and increases transcription and encapsulation of DNA into liposomes. It was shown that DNA condensed with Co(NH) was resistant to the action of the endonuclease DNase I such as DNA condensed with spermidine was. However, DNA condensed with Co(NH) was significantly less active in transcription with the E. coli RNA polymerase than DNA-spermidine condensed forms. In addition, it was demonstrated that both compacted forms of DNA were more efficiently encapsulated into neutral liposomes; however, negatively, charged liposomes were scarcely formed in the presence of DNA condensed with Co(NH). These experiments and the well documented properties of polyamines increasing the resistance to radiations and hydrolysis of nucleic acids, as well as their biological activities, such as replication, transcription, and translation, together with the low concentration of Co in the environment, lead us to propose spermidine as a plausible prebiotic DNA condensing agent rather than Co and the basic proteins proposed by other authors. Then, we consider the possible role and relevance of the polyamine-nucleic acids complexes in the evolution of life. [ABSTRACT FROM AUTHOR]

Liposomes formed from egg-yolk phosphatidylcholine:egg-yolk phosphatidate (molar ratio 2:1) containing pBR322 DNA and DNase I were induced to form, with divalent cations, bilayer/nonbilayer phase transitions of phosphatidate which allowed cation diffusion into liposomes; then cation diffusion was measured by the activation of the hydrolysis of DNase I on DNA. The formation of phosphatidate transitions on liposomes was demonstrated by freeze-fracture and P NMR, and a direct correlation between the formation of phosphatidate transitions and the transbilayer diffusion of cations was found: only Ca and Mn, which induce phase transitions, were able to penetrate liposomes and triggered the DNase I activity; in addition, Ca at higher concentrations (10 mM) caused fusion of liposomes, whereas Mn did not, suggesting that transitions induced by Mn participated only in the diffusion of this ion; furthermore, Mg neither formed phase transitions nor triggered the enzymatic activity. The liposomes studied represent more dynamic structures that can form phosphatidate structures involved in both (1) the interchange of divalent cations with the surroundings, thereby modulating encapsulated enzymes, and (2) the fusion of lipid vesicles probably implicated in the enrichment of liposomal content in the early Precambian Earth. [ABSTRACT FROM AUTHOR]

Transbilayer diffusion of Mn ions occurred in liposomes formed from dipalmitoyl-phosphatidylcholine or egg-yolk phosphatidylcholine and egg-yolk phosphatidate (molar ratio 2∶1) containing DNA and DNase I within their aqueous compartments. Cation diffusion was demonstrated by the hydrolytic activity of DNase I, activated by the Mn ions that diffused into the vesicles, and this was confirmed by light scattering. Phosphatidate, a cone-shaped lipid which has been synthesized under simulated prebiotic conditions, was necessary for cation diffusion across the liposome membranes. Such liposomes represent a simple precellular system that interchanges cations with the surroundings and provides a microenvironment for enzymatic reactions, as evidenced by the hydrolysis of DNA by DNase I inside these closed lipid compartments. [ABSTRACT FROM AUTHOR]