Protein diagenesis in Patella shells: implications for amino acid racemisation dating

Se analiza la racemización de aminoácidos en proteínas inter e intracristalinas en conchas de Patella y su utilización como herramienta geocronológica, fundamentalmente empleadas en yacimientos arqueológicos.The inter- and intra-crystalline fractions of Patella vulgata limpets recovered from archaeological sites in Northern Spain (covering Neolithic, Mesolithic, Magdalenian, Solutrean, and Aurignacian periods) were examined for amino acid composition and racemisation over time. The calcitic apex and rim areas of the shells were found to probably be composed of similar proteins, as the D/L values and amino acids were comparable and varied in the same way with increasing age; however, the mineral structures present in these areas differed. The aragonitic intermediate part of the shell showed a distinctly different amino acid composition and mineral structure. The main protein leaching from the inter-crystalline fraction occurred within the first 6000 yr after the death of the organism. In contrast, the intra-crystalline fraction — comprised of a different protein composition than the inter-crystalline fraction — appeared to behave as a closed system for at least 34 ka, as reflected by the lack of a significant decrease in the amino acid content; however, changes in the amino acid percentages occurred during this period. The concentration of aspartic acid remained almost constant with age both in inter- and intra-crystalline proteins, and its contribution to the total amino acid content increased with age at the expense of other amino acids such as glutamic acid, serine, glycine and alanine. Temperature is thought to play a key role in the amino acid racemisation of P. vulgata and could explain why in the localities belonging to the Gravettian and Solutrean period, which formed during relatively cold conditions, D/L values were similar to those detected in shells from sites formed during the Magdalenian.

Effect of level of fiber of the rearing phase diets on egg production, digestive tract traits, and body measurements of brown egg-laying hens fed diets differing in energy concentration

This research studied the effects of additional fiber in the rearing phase diets on egg production, gastrointestinal tract (GIT) traits, and body measurements of brown egg-laying hens fed diets varying in energy concentration from 17 to 46 wk of age. The experiment was completely randomized with 10 treatments arranged as a 5 × 2 factorial with 5 rearing phase diets and 2 laying phase diets. During the rearing phase, treatments consisted of a control diet based on cereals and soybean meal and 4 additional diets with a combination of 2 fiber sources (cereal straw and sugar beet pulp, SBP) at 2 levels (2 and 4%). During the laying phase, diets differed in energy content (2,650 vs. 2,750 kcal AMEn/kg) but had the same amino acid content per unit of energy. The rearing diet did not affect any production trait except egg production that was lower in birds fed SBP than in birds fed straw (91.6 and 94.1%, respectively; P < 0.05). Laying hens fed the high energy diet had lower feed intake (P < 0.001), better feed conversion (P < 0.01), and greater BW gain (P < 0.05) than hens fed the low energy diet but egg production and egg weight were not affected. At 46 wk of age, none of the GIT traits was affected by previous dietary treatment. At this age, hen BW was positively related with body length (r = 0.500; P < 0.01), tarsus length (r = 0.758; P < 0.001), and body mass index (r = 0.762; P < 0.001) but no effects of type of diet on these traits were detected. In summary, the inclusion of up to 4% of a fiber source in the rearing diets did not affect GIT development of the hens but SBP reduced egg production. An increase in the energy content of the laying phase diet reduced ADFI and improved feed efficiency but did not affect any of the other traits studied.

Productive performance, carcass and meat quality of intact and castrated gilts slaughtered at 106 or 122 kg BW

A total of 200 (Landrace3Large White dam3Pietrain3Large White sire) gilts of 5063 days of age (23.361.47 kg BW) were used to investigate the effects of castration (intact gilt, IG v. castrated gilt, CG) and slaughter weight (SW; 106 v. 122 kg BW) on productive performance, carcass and meat quality. Four treatments were arranged factorially and five replicates of 10 pigs each per treatment. Half of the gilts were ovariectomized at 58 days of age (8 days after the beginning of the trial at 29.861.64 kg BW), whereas the other half remained intact. The pigs were slaughtered at 106 or 122 kg BW. Meat samples were taken at Musculus longissimus thoracis at the level of the last rib and subcutaneous fat samples were taken at the tail insertion. For the entire experimental period, CG had higher ( P,0.05) BW gain and higher ( P,0.001) backfat and Musculus gluteus medius fat thickness than IG. However, IG had higher ( P,0.05) loin and trimmed primal cut yields than CG. Meat quality was similar for IG and CG but the proportion of linoleic acid in subcutaneous fat was higher ( P,0.001) for IG. Pigs slaughtered at 122 kg BW had higher ( P,0.001) feed intake and poorer feed efficiency than pigs slaughtered at 106 kg BW. An increase in SW improved ( P,0.001) carcass yield but decreased ( P,0.05) trimmed primal cut yield. Meat from pigs slaughtered at the heavier BW was redder (a*; P,0.001) and had more ( P,0.01) intramuscular fat and less thawing ( P,0.05) and cooking ( P,0.10) loss than meat from pigs slaughtered at the lighter BW. In addition, pigs slaughtered at 122 kg BW had less ( P,0.01) linoleic acid content in subcutaneous fat than pigs slaughtered at 106 kg BW. Castration of gilts and slaughtering at heavier BW are useful practices for the production of heavy pigs destined to the dry-cured industry in which a certain amount of fat in the carcass is required. In contrast, when the carcasses are destined to fresh meat production, IG slaughtered at 106 kg BW is a more efficient alternative.

Down-Regulating γ-gliadins in bread wheat leads to non-specific increases in other gluten proteins and has no major effect on dough gluten strength.

Background Gliadins are a major component of gluten proteins but their role in the mixing of dough is not well understood because their contribution to wheat flour functional properties are not as clear as for the glutenin fraction. Methodology/Principal Findings Transgenic lines of bread wheat with γ-gliadins suppressed by RNAi are reported. The effects on the gluten protein composition and on technological properties of flour were analyzed by RP-HPLC, by sodium dodecyl sulfate sedimentation (SDSS) test and by Mixograph analysis. The silencing of γ-gliadins by RNAi in wheat lines results in an increase in content of all other gluten proteins. Despite the gluten proteins compensation, in silico analysis of amino acid content showed no difference in the γ-gliadins silenced lines. The SDSS test and Mixograph parameters were slightly affected by the suppression of γ-gliadins. Conclusions/Significance Therefore, it is concluded that γ-gliadins do not have an essential functional contribution to the bread-making quality of wheat dough, and their role can be replaced by other gluten proteins

Canopy fruit location can affect olive oil quality in Arbequina hedgerow orchards

The effect of location of fruit in canopies of hedgerow olive trees (Olea europaea L., cv. ‘Arbequina’) on quality of virgin oil was tested by analyzing oils extracted from different height layers and faces of 9 olive hedgerows (6 North-South oriented and 3 East-West). Although sensory attributes were not different other oil quality parameters may be significantly modified by fruit position. In some hedgerows, oils extracted from fruits harvested from higher layers exhibited significantly higher stability against oxidation, along with higher palmitic acid, linoleic acid and phenol contents, but lower oleic acid content. Oils extracted from fruits harvested from East and North facing hedgerows oriented North-South and East-West, respectively, exhibited higher oleic contents and lower saturated and polyunsaturated fatty acid contents. The mean phenol content of oils extracted from fruits from a North-South oriented hedgerow was significantly greater from one of the East-West oriented hedgerows. These findings may be relevant for the design of future olive hedgerows destined for olive oil production.

Simulation of oil productivity and quality of N-S oriented olive hedgerow orchards in response to structure and interception of radiation

Simulations of oil yield and quality are presented for N–S oriented, hedgerow olive orchards of a range of structures (viz. canopy depth, canopy width, canopy slope and row spacing) using responses of yield and quality parameters to solar irradiance on canopy walls measured in a range of orchards, cv. Arbequina, in Spain. Results reveal that orchard yield of hedgerows of rectangular shape reaches a maximum when canopy depth equals alley width (row spacing−canopy width) and decreases at wider spacing, and/or with wider canopies, as the length of productive row decreases per unit area. Maximum yields for 4-m deep canopies were 2885 kg ha−1 at 1-m width and 5-m row spacing, 2400 kg ha−1 at 2-m width and 6-m spacing, and 2050 kg ha−1 at 3-m width and 7-m spacing. Illumination of canopies can be increased by applying slopes to form rhomboidal hedgerows. Substantial yield advantage can be achieved, especially for wide hedgerows, partly by closer row spacing that increases row length per unit area. By comparison, responses to latitude in the range 30–40◦ are small and do not warrant different row spacing. Oil quality parameters also respond to orchard structure. Responses are presented for oleic and palmitic acid, stability, and maturity index. Oleic acid content declines as alley spacing increases and is smaller, shallow than in wide, deep canopies. Palmitic acid content, stability, and maturity index increase with row alley spacing and are greater in narrow, shallow than in wide, deep canopies.

Models for Internal Quality Fruit Sorting, Based on Time- Domain Laser Reflectance Spectroscopy (TDRS)

Time domain laser reflectance spectroscopy (TDRS) was applied for the first time to evaluate internal fruit quality. This technique, known in medicine-related knowledge areas, has not been used before in agricultural or food research. It allows the simultaneous non-destructive measuring of two optical characteristics of the tissues: light scattering and absorption. Models to measure firmness, sugar & acid contents in kiwifruit, tomato, apple, peach, nectarine and other fruits were built using sequential statistical techniques: principal component analysis, multiple stepwise linear regression, clustering and discriminant analysis. Consistent correlations were established between the two parameters measured with TDRS, i.e. absorption & transport scattering coefficients, with chemical constituents (sugars and acids) and firmness, respectively. Classification models were built to sort fruits into three quality grades, according to their firmness, soluble solids and acidity.

Canopy fruit location can affect olive oil quality in Arbequina hedgerow orchards.

The effect of location of fruit in canopies of hedgerow olive trees (Olea europaea L., cv. ‘Arbequina’) on quality of virgin oil was tested by analyzing oils extracted from different height layers and faces of nine olive hedgerows (6 North–South oriented and 3 East– West). Although sensory attributes were not different, other oil quality parameters may be significantly modified by fruit position. Oils extracted from fruits harvested from higher layers exhibited significantly higher stability against oxidation, along with higher palmitic acid, linoleic acid and phenol contents, but lower oleic acid content. Oils extracted from fruits harvested from East and North facing hedgerows oriented North–South and East–West, respectively, exhibited higher oleic contents and lower saturated and polyunsaturated fatty acid contents. The mean phenol content of oils extracted from fruits from a North–South oriented hedgerow was significantly greater from one of the East–West oriented hedgerows. These findings may be relevant for the design of future olive hedgerows destined for olive oil production.

Calidad poscosecha del tomate (Solanum lycopersicum L.) cultivado en sistemas ecológicos de fertilización

Se condujeron cuatro experimentos unifactoriales en condiciones de campo en áreas agrícolas de la Universidad de Granma, en el período comprendido de septiembre/2007 a enero/2010 para determinar el efecto de la aplicación de micorrizas arbusculares, Azotobacter chroococcum y ácidos húmicos sobre la productividad y la calidad poscosecha del tomate (Solanum lycopersicum L.) cv. “Vyta”, sobre un suelo de tipo Fluvisol. La aplicación simple y combinada de las micorrizas arbusculares, el Azotobacter chroococcum y los ácidos húmicos mostró un efecto positivo sobre la productividad de la variedad de tomate estudiada, al obtenerse incrementos significativos de este indicador en comparación con el control (sin aplicación), lográndose los mejores resultados con la combinación Glomus fasciculatum (0,3 kg m-2) + Azotobacter chroococcum (30 L ha-1) + ácidos húmicos (500 mg L-1) con valores de 54,57 t ha-1. Se comprobó además, que los tratamientos con estos bioproductos presentaron contenidos de sólidos solubles totales (SST), carbohidratos solubles totales (CST), vitamina C, porcentaje de materia seca (PMS), firmeza, longitud y anchura de los frutos superiores al control (sin aplicación). Las plantas controles (sin aplicación) significativamente incrementaron la acidez titulable (contenido de ácido cítrico) y la pérdida de peso y redujeron el pH de los frutos del tomate. Los análisis de correlación realizados revelan que existieron correlaciones positivas y significativas entre el contenido de vitamina C, materia seca, sólidos solubles totales, carbohidratos solubles totales, y el pH de los frutos, mientras que la acidez titulable presentó correlaciones negativas y significativas con todas las variables mencionadas anteriormente. Se encontró a su vez un efecto sinérgico en las plantas con la aplicación combinada de estos productos con respecto al control (sin aplicación), expresado en los mayores valores de los parámetros micorrízicos estudiados. ABSTRACT Four unifactorial experiments under field conditions in an agricultural area belonging to the University of Granma from September/2007 to January/2010 aiming to evaluate the effect of arbuscular mycorrhizas, Azotobacter and humic acids on tomato (Solanum lycopersicum L) cv. “Vyta” crop yield and postharvest quality in a Typic Fluvent soil were conducted. The simple and mixed application of arbuscular mycorrhizas, Azotobacter chroococcum and humic acids showed a positive effect on yield and internal postharvest parameters evaluated for the studied tomato variety, achieving significant increases with respect to the control treatment ones. The best results related to crop yield were achieved by combining Glomus fasciculatum (0.3 kg m-2) + Azotobacter chroococcum (30 L ha-1) + humic acids (500 mg L-1) that lead to 54.57 t ha-1. In addition, it was also demonstrated that the treatments under effect of biofertilizers and biostimulants resulted in higher total soluble solids (TSS), total soluble carbohydrates (TSC), vitamin C, dry matter contents (DMC), firmness, length and width of the fruits than the control treatment. The control plants showed significantly increased titrable acidity (citric acid content) and weight loss and reduced pH on the tomato fruits. The conducted correlation analyses revealed that there were significant and positive correlations between vitamin C content, dry matter, total soluble solids, total soluble carbohydrates, and pH of the fruit, while titratable acidity showed significant negative correlations with all variables mentioned above. At the same time, a synergic effect by mixed utilization of these biological products on tomato plants, with respect to control treatment (non-treated), was found regarding the increase of studied mycorrhizal parameters.

Influence of castration on growth performance and carcass and meat quality of heavy female pigs

The main objetive of this Doctoral Thesis was to study the influence of female castration and pig sex on growth performance and carcass and meat quality of white pigs slaughtered at different final weights. Three experiments (Exp.) were conducted. In Exp. 1, a total of 200 (Landrace * Large White dam x Pietrain * Large White sire) gilts of 50 ± 3 days of age (23.3 ± 1.47 kg BW) was used to investigate the effects of castration (intact females, IF vs. castrated feamles, CF) and slaughter weight (106 vs. 122 kg BW) on productive performance and carcass and meat quality. There were four experimental treatments arranged as a 2 x 2 factorial and 5 replicates of 10 pigs each per treatment. Half of the gilts were ovariectomized at 58 d of age (8 days after the beginning of the trial; 29.8 ± 1.64 kg BW) whereas the other half remained intact. Meat samples were taken at m. Longissimus thoracis at the level of the last rib and subcutaneous fat samples were taken at the tail insertion. For the entire experiment period, CF had higher BW gain (P<0.05) and backfat and m. Gluteus medius (GM) fat thickness (P<0.001) than IF. However, IF had higher loin and trimmed primal cut yields (P<0.05) than CF. Meat quality was similar for IF and CF but the proportion of linoleic acid in subcutaneous fat was higher (P<0.001) for IF. Pigs slaughtered at 122 kg BW had higher (P<0.001) feed intake and poorer feed efficiency than pigs slaughtered at 106 kg BW. An increase in slaughter weight (SW) improved (P<0.001) carcass yield but decreased (P<0.05) trimmed primal cut yield. Meat from females slaughtered at the heavier BW was redder (a*; P<0.001) and had more (P<0.01) intramuscular fat and less thawing (P<0.05) and cooking (P<0.10) loss than meat from females slaughtered at the lighter BW. Also, females slaughtered at 122 kg BW had less (P<0.01) linoleic acid content in the subcutaneous fat than pigs slaughtered at 106 kg BW. Castration of gilts and slaughtering at heavier BW might be useful practices for the production of heavy pigs destined to the dry cured industry in which a certain amount of fat in the carcass is required. In contrast, when the carcasses are destined to fresh meat production, IF slaughtered at 106 kg BW are a more efficient alternative. In Exp. 2, crossbred pigs (n=240) from Pietrain*Large White sires mated to Landrace*Large White dams with an average of 100 d of age (60.5 ± 2.3 kg) were used to investigate the effects of gender and slaughter weight (SW) on growth performance and carcass and meat quality characteristics. There were 6 treatments arranged factorially with 3 genders (IF vs. CF vs.castrated males, CM) and 2 SW (114 vs. 122 kg BW). Each of the 6 combinations of treatments was replicated 4 times and the experimental unit was a pen with 10 pigs. Castrated males and CF ate more feed, grew faster and had more carcass backfat depth and fat thickness at the GM muscle, but lower loin yield than IF (P<0.05). In addition, CF and CM had more intramuscular fat (P<0.05) and less linoleic acid content in the subcutaneous fat (P<0.01) than IF. Pigs slaughtered at 122 kg BW had lower ADG (P<0.05), poor gain-to-feed ratio (P<0.05), and more GM fat than pigs slaughtered at 114 kg BW (P < 0.05). It is concluded that CF and CM had similar productive performance and meat quality characteristics when slaughtered at the same age, and that the castration of females improved daily gains and increased weight and fat content of primal cuts with respect to IF. Therefore, castration of females is recommended in pigs destined to the dry-cured industry because of the beneficial effects on the quality of the primal cuts. In Exp. 3, the effects of gender and castration of females (IF vs. CF vs. CM) on performance and carcass and meat quality were studied in crossbred pigs (Landrace x Large White dams x Duroc sires) slaughtered at 119.2 (trial 1) or 131.6 (trial 2) kg BW. Intact females had better feed conversion and less carcass fat than CF and CM. Trimmed shoulder yield was higher for CM than for CF with IF being intermediate. Primal cut yield and meat quality, however were similar for all treatments. Proportion of linoleic acid in backfat was lower for CF than for IF or CM, and the differences were significant in pigs slaughtered witn 131.6 kg BW. The higher fat content and the fatty acid profile favour the use of CF and CM over IF for the production of heavy pigs destined to the dry-cured industry.

Lipid biomarkers in the Enol Lake (Asturias, Northern Spain): coupled natural and human induced environmental history

The lipid content of three cores from Lake Enol (Picos de Europa National Park, Asturias, Northern Spain) was studied. The n-alkane profiles indicated a major input from terrigenous plants [predominance of high molecular weight (HMW) alkanes] since ca. 1695 AD to the water body, although the uppermost cm revealed a predominance of organic matter (OM) derived from algae, as the most abundant alkane was C17. Three units revealing different environmental conditions were defined. Unit A (ca. 1695–1860 AD) in the lowermost parts of ENO13-10 (< 12 cm) and ENO13-15 (< 28 cm) was identified and was characterized by higher OM input and evidence of minimal degradation (high CPI values, predominance of HMW n-alkanoic acids and good correspondence between the predominant n-alkane and n-alkanoic acid chains). These findings could be linked to the Little Ice Age, when cold and humid conditions may have favored an increase in total organic carbon (TOC) and n-alkane and n-alkanoic acid content (greater terrigenous OM in-wash), and may have also reduced bacterial activity. In Unit B (ca. 1860–1980 AD) the lack of correspondence between the n-alkane and n-alkanoic acid profiles of ENO13-10 (12–4 cm) and ENO13-15 (28–8 cm) suggested a certain preferential microbial synthesis of long chain saturated fatty acids from primary OM and/or bacterial activity, coinciding with a decrease in OM input, which could be linked to the global warming that started in the second half of the 19th century. In ENO13-7 the low OM input (low TOC) was accompanied by some bacterial degradation (predominance ofHMWn-alkanoic acids but with a bimodal distribution) in the lowermost 16–5 cm. Evidence of considerable phytoplankton productivity and microbial activity was especially significant in Unit C (ca. 1980–2013 AD) identified in the uppermost part of all three cores (5 cm in ENO13-7, 4 cm in ENO13-10 and 8 cm in ENO13-15), coinciding with higher concentrations of n-alkanes and n-alkanoic acids, which were considered to be linked to warmer and drier conditions, as well as to greater anthropogenic influence in modern times. Plant sterols, such as b-sitosterol, campesterol and stigmasterol, were significantly present in the cores. In addition, fecal stanols, such as 24-ethylcoprostanol from herbivores, were present, thereby indicating a continuous and significant pollution input derived from these animals since the 17th century, being more important in the last 20 years.

Effect of crude protein and fat content of diets with similar indispensable amino acid profile on productive performance and egg quality of brown egg laying hens differing in initial body weight

In total of 504 Lohmann Brown hens were used to study the influence of the initial BW of the birds and the crude protein (CP) and fat content of the diet on performance and egg quality traits from 22 to 49 weeks of age. The experiment was completely randomized with 8 treatments arranged factorially with 2 initial BW (1,726 vs. 1,987g) and 4 diets with similar AMEn (2,750 kcal AMEn/ kg) and indispensable (lys, Met+Cys, Thr, and Trp) amino acid contents.

Amelioration of a degraded acid soil from SW Spain by no-tillage and Ca-amendment

En los suelos, el exceso de acidez lleva asociado deficiencias en ciertos nutrientes y una alta disponibilidad de aluminio, tóxico para los cultivos propios del ambiente mediterráneo. Su laboreo, provoca la pérdida de materia orgánica (MO), deteriora su estructura y reduce la actividad biológica, provocando en última instancia una menor calidad del suelo. Es de esperar pues que cuando se labran suelos ácidos, sus problemáticas particulares tiendan a agravarse. En nuestra zona de estudio, la “raña” de Cañamero (Extremadura, España), predominan los suelos muy ácidos y degradados por un laboreo inadecuado. Las rañas constituyen amplias plataformas casi horizontales, con unos suelos muy viejos (Palexerults), que se caracterizan por tener el complejo de cambio dominado por el aluminio, y un pH ácido que decrece en profundidad. Poseen un potente horizonte Bt rico en arcillas caoliníticas, que propicia que en periodos con exceso de lluvia, se generen capas colgadas de agua cercanas a la superficie. En torno a los años 1940’s estos suelos, que previamente sostenían un alcornocal, o su matorral de sustitución, se pusieron en cultivo. El laboreo aceleró la mineralización de la materia orgánica, agravó los problemas derivados del exceso de acidez y condujo al abandono de los campos cultivados por falta de productividad. Para recuperar la calidad de estos suelos degradados y obtener unos rendimientos compatibles con su uso agrícola es necesario, por un lado, aplicar enmiendas que eleven el pH y reduzcan la toxicidad del aluminio y, por otro, favorecer el incremento en el contenido en MO. En 2005 se implantó en esta raña un ensayo de campo para estudiar la influencia del no laboreo y de la utilización de una enmienda cálcica en parámetros relacionados con la calidad del suelo en un cultivo forrajero. El diseño experimental fue en parcelas divididas con cuatro repeticiones donde el factor principal fue el tipo de laboreo, no laboreo (NL) frente a laboreo convencional (LC), y el factor secundario el uso o no de una enmienda cálcica. La enmienda consistió básicamente en una mezcla de espuma de azucarería y yeso rojo y se incorporó al comienzo del ensayo hasta los 7 cm de profundidad. Desde el comienzo del ensayo el NL influyó positivamente en el contenido de carbono orgánico total (COT) y particulado (COP), mientras que la enmienda tuvo una ligera influencia al principio del ensayo en ambos pero su efecto positivo se desvaneció con el paso del tiempo. Los mayores contenidos en COT y POC se observaron cuando se combinó el NL con la enmienda. La enmienda incrementó con rapidez el pH, y el Ca, y disminuyó el contenido en aluminio hasta una profundidad de 50 cm, incluso en NL, y mejoró ligeramente la agregación del suelo. El NL por sí solo, gracias al aumento en POC, TOC y las proteínas del suelo relacionadas con la glomalina (PSRG), que son capaces de formar compuestos estables no tóxicos con el aluminio, también contribuyó a la reducción de la toxicidad de aluminio en la capa más superficial. Cuando en las campañas con exceso de precipitaciones se generaron capas colgadas de agua próximas a la superficie, el NL generó unas condiciones más favorables para la germinación y desarrollo del cultivo, resultando en una producción más alta que el LC. A ello contribuyó la mayor capacidad de almacenamiento de agua y la mayor transmisividad de esta hacia abajo, en la capa más superficial (0-5 cm) que propició una menor saturación por agua que el LC. Respecto a los parámetros relacionados con la agregación, el NL aumentó los macroagregados hasta los 10 cm de profundidad y favoreció la acumulación de CO y N en todas las fracciones de tamaño de agregados. Sin embargo, la recuperación del grado de macroagregación tras el cese del laboreo resulta lenta en comparación con otros suelos, posiblemente debido al bajo contenido en arcilla en el horizonte Ap. En comparación con el NL, la enmienda mostró también un efecto positivo, aunque muy ligero, en la agregación del suelo. En contradicción con otros estudios en suelos ácidos, nuestros resultados indican la existencia de una jerarquía de agregados, y destacan el papel importante de la MO en la mejora de la agregación. Tanto el NL como la enmienda favorecieron por separado varias propiedades químicas, físicas y biológicas del suelo, pero, en general, encontramos los mayores beneficios con su uso combinado. Además, a largo plazo el efecto positivo de NL en las propiedades del suelo fue en aumento, mientras que el efecto beneficioso de la enmienda se limitó básicamente a las propiedades químicas y se desvaneció en pocos años. Destacamos que las condiciones meteorológicas a lo largo del ensayo beneficiaron la producción de biomasa en NL, y en consecuencia las propiedades relacionadas con la materia orgánica, por lo que son un factor a tener en cuenta a la hora de evaluar los efectos de la enmienda y el laboreo sobre las propiedades del suelo, especialmente en zonas donde esas condiciones son muy variables entre una campaña y otra. Los resultados de este estudio han puesto de manifiesto que el NL no ha mermado la eficacia de la enmienda caliza, posiblemente gracias a la alta solubilidad de la enmienda aplicada, es más, el manejo con NL y enmienda es el que ha favorecido en mayor medida ciertos parámetros de calidad del suelo. Por el contrario el LC sí parece anular los beneficios de la enmienda en relación con las propiedades relacionadas con la MO. Por tanto, cabe concluir que la combinación de NL y la enmienda es una práctica adecuada para mejorar las propiedades químicas y físicas de suelos ácidos degradados por el laboreo. ABSTRACT Excessive acidity in soils is associated with deficiencies in certain nutrients and high concentrations of available aluminum, which is toxic for most Mediterranean crops. Tilling these soils results in the loss of soil organic matter (SOM), damages soil structure and reduces biological activity, ultimately degrading soil quality. It is expected, therefore, that when acid soils are tilled, their particular problems will tend to get worse. In our study area, the "Cañamero’s Raña” (Extremadura, Spain), acid soils degraded by an inappropriate tillage prevail. Rañas are large and flat platforms with very old soils (Palexerults), which are characterized by an exchange complex dominated by aluminum and an acid pH which decreases with depth. These soils have a strong Bt horizon rich in kaolinite clays, which encourages the formation of perched water-tables near the soil surface during periods of excessive rain. During the first third of the 20th century, these soils, that previously supported cork oak or its scrub replacement, were cultivated. Tillage accelerated the mineralization of the SOM, aggravating the problems of excessive acidity, which finally led to the abandonment of the land due to low productivity. To recover the quality of these degraded soils and to obtain consistent yields it is necessary, first, to apply amendments to raise the pH and reduce aluminum toxicity, and second to encourage the accumulation of SOM. In 2005 a field trial was established in the Raña to study the influence of no-tillage and the use of a Ca-amendment on soil quality related parameters in a forage crop agrosystem. The experimental design was a split-plot with four replicates where the main factor was tillage type, no-tillage (NT) versus traditional tillage (TT) and the secondary factor was the use or not of a Ca-amendment. The Ca-amendment was a mixture of sugar foam and red gypsum that was incorporated into the top 7 cm of the soil. Since the beginning of the experiment, NT had a positive influence on total and particulate organic carbon (TOC and POC, respectively), while the Ca-amendment had a small positive influence at the beginning of the study but its effect diminished with time. The highest TOC and POC contents were observed when NT and the Ca-amendment were combined. The Ca-amendment, even under NT, rapidly increased pH and Ca, and decreased the aluminum content to a depth of 50 cm, as well as improving soil aggregation slightly. NT, due to the increased POC, TOC and Glomalin-related soil proteins (GRSP), which can form stable non-toxic compounds with aluminum, also contributed to the reduction of aluminum toxicity in the upper layer. When perched water-tables near the soil surface were formed in campaigns with excessive rainfall, NT provided more favorable conditions for germination and crop development, resulting in higher yields compared with TT. This was directly related to the higher water storage capacity and the greater transmissivity of the water downwards from the upper layers, which led to lower water saturation under NT compared with TT. With regards to the aggregation-related parameters, NT increased macroaggregation to a depth of 10 cm and favored the accumulation of OC and N in all aggregate size fractions. However, the degree of recovery of macroaggregation after tillage ceased was slow compared with other soils, possibly due to the low clay content in the Ap horizon. Compared with NT, the Ca-amendment had a slight positive effect on soil aggregation. In contrast to other studies in acid soils, our results indicate the existence of an aggregate hierarchy, and highlight the important role of SOM in improving aggregation. Both NT and the Ca-amendment separately favored various chemical, physical and biological soil properties, but in general we found the greatest benefits when the two treatments were combined. In addition, the positive effect of NT on soil properties increased with time, while the beneficial effect of the Ca-amendment, which was limited to the chemical properties, vanished after a few years. It is important to note that the meteorological conditions throughout the experiment benefited biomass production under NT and, as a consequence, organic matter related properties. This suggests that meteorological conditions are a factor to consider when evaluating the effects of Ca-amendments and tillage on soil properties, especially in areas where such conditions vary significantly from one campaign to another. The results of this study show that NT did not diminish the effectiveness of the Ca-amendment, possibly due to the high solubility of the selected amendment. Moreover, the combination of NT and the Ca-amendment was actually the management that favored certain soil quality parameters the most. By contrast, TT seemed to nullify the benefits of the Ca-amendment with regards to the OM related properties. In conclusion, the combination of NT and the application of a Ca-amendment is an advisable practice for improving the chemical and physical properties of acid soils degraded by tillage.

Asymmetric amplification in amino acid sublimation involving racemic compound to conglomerate conversion

A straightforward unprecedented sublimation protocol that reveals both conversion of a racemic compound into a racemic conglomerate and subsequent enantioenrichment has been developed for the proteinogenic amino acid valine. The phenomenon has been observed in closed and open systems, providing insight into asymmetric amplification mechanisms under presumably prebiotic conditions

Effect of fibers and whole grain content on quality attributes

Incorporation of fiber in cereals may lead to quality issues, thus decreasing consumer acceptance. This is partially due to deterioration of the microstructure, one of the primary quality attributes of cereals. The objective of this study was to better understand the mechanisms by which dietary fibers affect the quality of cereal products during extrusioncooking. The study quantified the effect of amount and type of fiber and whole grain on (i) texture, (ii) structure, and (iii) rehydration properties of extruded cereals. New innovative methods were applied and combined with traditional techniques to characterize both the structure and the rehydration properties. Extruded cereals were produced using a starch-based recipe (whole and wheat flours) and two sources of fibers (oat bran concentrate and wheat bran). The oat and wheat bran levels used in this study were 0, 10, and 20%. The different mixtures were extruded in a pilot twinscrew extruder BC21 (Clextral) and then sugar coated after drying. Mechanical properties of extruded cereals were investigated by compression test. The cellular structure was observed by X-ray tomography. The quality of coating (thickness, homogeneity) was analyzed by optical coherence tomography. The rehydration properties of such cereals in milk were evaluated by magnetic resonance imaging and optical coherence tomography. This work revealed that structure assessment of extruded cereals may lead to a better understanding of the effect of fiber addition on texture and rehydration properties. The application of innovative methods, such as optical coherence tomography and magnetic resonance imaging, was found to be useful to quantify the structural properties.