Antonio Serrano

Myosin isoforms and muscle fiber characteristics in equine gluteus medius muscle

To date, four different myosin heavy chain (MyHC) isoforms have been identified in adult skeletal muscle of a number of species: types I, IIa, IIx or IId, and IIb. The aim of this study was to investigate the distribution of various MyHC isoforms in the equine gluteus medius and gluteus profundus muscles in relation with several morphometric variables of muscle fibers.

Simultaneous liquid-liquid microextraction/methylation for the determination of haloacetic acids in drinking waters by headspace gas chromatography.

A novel analytical method that combines simultaneous liquid-liquid microextraction/methylation and headspace gas chromatography-mass spectrometry for the determination of nine haloacetic acids (HAAs) in water was reported. A mechanistic model on the basis of mass transfer with chemical reaction in which methylation of HAAs was accomplished in n-pentane-water (150 microl-10 ml) two-phase system with a tetrabutylammonium salt as phase transfer catalyst was proposed. Derivatisation with dimethylsulphate was completed in 3 min by shaking at room temperature. The methyl ester derivatives and the organic phase were completely volatilised by static headspace technique, being the gaseous phase analysed. Parameters related to the extraction/methylation and headspace generation of HAAs were studied and the results were compared with methyl haloacetate standards to establish the yield of each step. The thermal instability of HAAs, by degradation to their respective halogenated hydrocarbon by decarboxylation, and the possible hydrolysation of the methyl esters were rigorously controlled in the whole process to obtain a reliable and robust method. The proposed method yielded detection limits very low which ranges from 0.02 to 0.4 microg l(-1) and a relative standard deviation of ca. 7.5%. Finally, the method was validated with the US Environmental Protection Agency (EPA) method 552.2 for the analysis of HAAs in drinking and swimming pool water samples containing concentrations of HAAs that must be higher than 10 microg l(-1) due to the fact that this method is less sensitive than the proposed one.

Semi-continuous anaerobic co-digestion of orange peel waste and residual glycerol derived from biodiesel manufacturing.

The manufacturing of orange juice generates high volumes of orange peel waste which should not be deposited in landfill according to current recommendations. Furthermore, glycerol is a compound co-generated in biodiesel manufacturing, but the volume generated is higher than the current demand for pure glycerol. The anaerobic co-digestion of orange peel waste with residual glycerol could reduce the inhibitory effect of some compounds and provide a correct nutrient balance. Under mesophilic temperature and semi-continuous conditions, a mixture of orange peel waste-residual glycerol of 1:1 (in COD) operated favorably for organic loads up to 2.10 g VS/L. At higher organic loads, the accumulation of volatile fatty acids (VFA) and a decrease in the pH caused process destabilization. The methane yield coefficient was quite constant, with a mean value of 330±51 mL(STP)/g VSadded, while the organic loading rate (OLR) reached a mean value of 1.91±0.37 kgVS/m3 d (17.59±2.78 kgmixture/m3 d) and the hydraulic retention time (HRT) varied in a range of 8.5-30.0 d.

Evaluation of soil biological activity after a diesel fuel spill

Diesel fuel contamination in soils may be toxic to soil microorganisms and plants and acts as a source of groundwater contamination. The objective of this study was to evaluate the soil biological activity and phytotoxicity to garden cress (Lepidium sativum L.) in a soil polluted with diesel fuel. For this, a diesel fuel spill was simulated on agricultural soil at dose 1 l m(-2). During the experiment (400 days) the soil was not covered in vegetation and no agricultural tasks were carried out. A stress period of 18 days following the spill led to a decrease in soil biological activity, reflected by the soil microbial biomass and soil enzymatic activities, after which it increased again. The n-C(17)/Pristine and n-C(18)/Phytane ratios were correlated negatively and significantly with the dehydrogenase, arylsulphatase, protease, phosphatase and urease activities and with the soil microbial biomass during the course of the experiment. The beta-glucosidase activity indicated no significant connection with the parameters related with the evolution of hydrocarbons in the soil. Finally, the germination activity of the soil was seen to recover 200 days after the spill.

Stimulation of onion root elongation by ascorbate and ascorbate free radical inAllium cepa L.

SummaryWe report that ascorbate free radical stimulates onion root growth at 15 °C and 25 °C. The fully reduced form, ascorbate, also stimulates root elongation if culture conditions allow its oxidation. When ascorbate oxidation was inhibited, no stimulation of root growth was found. The effect of the fully oxidized form, dehydroascorbate, was inhibitory. We show also that ascorbate free radical generated by ascorbate oxidation, is reduced back probably by a transplasmalemma reductase. These results are discussed on the basis of an activation of a transplasma membrane redox system likely involved in processes related to cell growth.

Improvement of mesophilic anaerobic co-digestion of agri-food waste by addition of glycerol.

Anaerobic co-digestion is a promising alternative to manage agri-food waste rather than landfilling, composting or incineration. But improvement of methane yield and biodegradability is often required to optimize its economic viability. Biomethanization of agri-food solid waste presents the disadvantage of a slow hydrolytic phase, which might be enhanced by adding a readily digestible substrate such as glycerol. In this study, strawberry extrudate, fish waste and crude glycerol derived from biodiesel manufacturing are mixed at a proportion of 54:5:41, in VS (VS, total volatile solids), respectively. The mesophilic anaerobic co-digestion at lab-scale of the mixture was stable at loads lower than 1.85 g VS/L, reaching a methane yield coefficient of 308 L CH4/kg VS (0 °C, 1 atm) and a biodegradability of 96.7%, in VS. Moreover, the treatment capacity of strawberry and fish waste was increased 16% at adding the crude glycerol. An economic assessment was also carried out in order to evaluate the applicability of the proposed process. Even in a pessimistic scenario, the net balance was found to be positive. The glycerol adding implied a net saving in a range from 25.5 to 42.1 €/t if compared to landfill disposal.

Myosin heavy chain profile of equine Gluteus medius muscle following prolonged draught-exercise training and detraining

Fourteen 4-year old Andalusian mares were used to examine the plasticity of myosin heavy chain (MHC) composition in horse skeletal muscle with heavy draught-exercise training and detraining. Seven horses underwent a training programme based on carriage exercises for 8 months. Afterwards, they were kept in paddocks for 3 months. The remaining seven animals were used as control horses. Three gluteus medius muscle biopsies were removed at depths of 20, 40 and 60 mm from each horse before (month 0), during the training (months 3 and 8) and after detraining (month 11). Myosin heavy chain composition was analysed by electrophoresis and immunohistochemically with anti-MHC monoclonal antibodies. Fibre areas, oxidative capacity and capillaries were studied histochemically. After 8 months of training, MHC-IIX and IIX fibres decreased whereas MHC-I and type I and I + IIA fibres increased. Neither MHC-IIA nor the percentage of IIA fibres changed when the data were considered as a whole, but the proportion of MHC-IIA increased in the superficial region of the muscle after 8 months of training. Mean areas of type II fibres were not affected by training and detraining, but the cross-sectional of type I fibres increased after 3 month of training and not further increases were recorded afterward. The percentage of high-oxidative capacity fibres and the number of capillaries per mm2 increased with training. Most of these muscular adaptations reverted after detraining. These results indicate that long term draught-exercise training induces a reversible transition of MHC composition in equine muscle in the order IIX → IIA → I. The physiological implication of these changes is an impact on the velocity of shortening and fatigue resistance of muscle fibres.

Evaluation of the improvement of sonication pre-treatment in the anaerobic digestion of sewage sludge.

Sewage sludge is a polluting and hazardous waste generated in wastewater treatment plants with severe management problems. The high content in heavy metal, pathogens and micropolluting compounds limit the implementation of the available management methods. Anaerobic digestion could be an interesting treatment method, but must be improved since the biomethanisation of sewage sludge entails low biodegradability and low methane production. A sonication pre-treatment at lab scale is proposed to increase the organic matter solubilisation of sewage sludge and enhance the biomethanisation yield. Sonication time was optimised by analysing the physicochemical characteristics of sewage sludge (both total and soluble fraction) at different pre-treatment times. The pre-treatment time was fixed at 45 min under the study conditions given that the solubilisation of organic matter did not increase significantly at lower sonication times, whereas the concentration of total nitrogen increased markedly at higher times. The volatile fatty acids generation rate was also evaluated for the pre-treatment conditions. The anaerobic digestion of untreated and pre-treated sewage sludge was subsequently compared and promising results were obtained for loads of 1.0 g VS/L (VS, total volatile solids). The methane yield coefficient increased from 88 to 172 mLSTP/g VS (STP, 0 °C, 1 atm) after the pre-treatment, while biodegradability was found to be around 81% (in VS). Moreover, the allowed organic loading rate and methane production rate observed for the sewage sludge reached values of up to 4.1 kg VS/m(3)·d and 1270 LSTP/m(3)·d, respectively.

Relationship between apoplastic ascorbate regeneration and the stimulation of root growth in Allium cepa L.

Abstract Ascorbate free radical stimulated onion root growth when bulbs were incubated at 15°C and 25°C. The fully oxidized form, dehydroascorbate, was inhibitory. Ascorbate only stimulated cell elongation if it underwent appreciable autoxidation at 25°C or at 15°C in the presence of small amounts of Cu 2+ . When ascorbate oxidation was inhibited, no stimulation of root growth was found at 25°C. Ascorbate oxidation rate was lower in the presence of onion roots, indicating that ascorbate free radical may be used as an electron acceptor for the transplasma membrane redox system regenerating ascorbate. The activation of this system could explain the reported growth stimulation.

Monitoring of pile composting process of OFMSW at full scale and evaluation of odour emission impact

In this study, the evolution of odour concentration (ouE/m(3)STP) emitted during the pile composting of the organic fraction of municipal solid waste (OFMSW) was monitored by dynamic olfactometry. Physical-chemical variables as well as the respirometric variables were also analysed. The aim of this work was twofold. The first was to determine the relationship between odour and traditional variables to determine if dynamic olfactometry is a feasible and adequate technique for monitoring an aerobic stabilisation process (composting). Second, the composting process odour impact on surrounding areas was simulated by a dispersion model. The results showed that the decrease of odour concentration, total organic carbon and respirometric variables was similar (around 96, 96 y 98% respectively). The highest odour emission (5224 ouE/m(3)) was reached in parallel with the highest microbiological activity (SOUR and OD20 values of 25 mgO2/gVS · h and 70 mgO2/gVS, respectively). The validity of monitoring odour emissions during composting in combination with traditional and respirometric variables was demonstrated by the adequate correlation obtained between the variables. Moreover, the quantification of odour emissions by dynamic olfactometry and the subsequent application of the dispersion model permitted making an initial prediction of the impact of odorous emissions on the population. Finally, the determination of CO2 and CH4 emissions allowed the influence of composting process on carbon reservoirs and global warming to be evaluated.