Optimizing conditions for the extraction of pigments in cochineals (Dactylopius coccus Costa) using response surface methodology

A simple method was developed for the extraction and determination of color pigments in cochineals (Dactylopius coccus Costa). The procedure was based on the solvent extraction of pigments in insect samples using methanol:water (65:35, v:v) as extractant. Two-level factorial design was used in order to optimize the solvent extraction parameters: temperature, time, methanol concentration in the extractant mixture, and the number of extractions. The results suggest that the number of extractions is statistically the most significant factor. The separation and determination of the pigments was carried out by high-performance liquid chromatography with UV-visible detection. Because the absorption spectra of different pigments are different in the visible region, it is convenient to use a diode array detector to obtain chromatographic profiles that allow for the characterization of the extracted pigments.     

Permeability of starch gel matrices and select films to solvent vapors

Volatile agrochemicals such as 2-heptanone have potential in safely and effectively controlling important agricultural pests provided that they are properly delivered. The present study reports the permeability of starch gel matrices and various coatings, some of which are agricultural-based, that could be used in controlled release devices. Low-density, microcellular starch foam was made from wheat, Dent corn, and high amylose corn starches. The foam density ranged from 0.14 to 0.34 g/cm3, the pore volume ranged from 74 to 89%, and the loading capacity ranged from 2.3 to 7.2 times the foam weight. The compressive properties of the foam were not markedly affected by saturating the pore volume with silicone oil. The vapor transmission rate (VTR) and vapor permeability (VP) were measured in dry, porous starch foam and silicone-saturated starch gels. VTR values were highest in foam samples containing solvents with high vapor pressures. Silicone oil-saturated gels had lower VTR and VP values as compared to the dry foam. However, the silicone oil gel did not markedly reduce the VP for 2-heptanone and an additional vapor barrier or coating was needed to adequately reduce the evaporation rate. The VP of films of beeswax, paraffin, ethylene vinyl alcohol, a fruit film, and a laminate comprised of beeswax and fruit film was measured. The fruit film had a relatively high VP for polar solvents and a very low VP for nonpolar solvents. The laminate film provided a low VP for polar and nonpolar solvents. Perforating the fruit film portion of the laminate provided a method of attaining the target flux rate of 2-heptanone. The results demonstrate that the vapor flux rate of biologically active solvents can be controlled using agricultural materials.     

Relationship between vegetation diversity and soil functional diversity in native mixed-oak forests

Most studies on the interactions between aboveground vegetation and belowground soil diversity have been carried out in microcosms or manipulated field plots. In the current study, we investigated the relationship between forest vegetation diversity and soil functional diversity (calculated from the activity of soil enzymes) in naturally developed plant communities of native mixed-oak forests without imposing any disturbances to already existing plant–soil relationships. In order to do so, five different vegetation types, i.e., herbaceous plants, climbing plants, trees, shrubs, and ferns, were considered. Correlations between plant diversity, soil physicochemical properties, and soil enzyme activities were determined. Soil physicochemical parameters appeared strongly correlated with both enzyme activities (e.g., pH was positively correlated with amidase and arylsulphatase, and negatively with acid phosphatase; OM content was positively correlated with β-glucosidase, acid and alkaline phosphatase and urease, and negatively with amidase; total N was positively correlated with β-glucosidase, and acid and alkaline phosphatase, and negatively with amidase) and soil functional diversity. For ferns, strong correlations between enzyme activities and plant diversity indexes were found (i.e., dehydrogenase was positively correlated with species richness and Shannon's diversity; acid and alkaline phosphatase were negatively correlated with Shannon's diversity; acid phosphatase was also negatively correlated with species richness). Most interestingly, herbaceous plants and ferns showed a strong positive correlation between Shannon's plant diversity and soil functional diversity. Furthermore, herbaceous plants showed a strong positive correlation between species richness and soil functional diversity. Although these correlations between plant diversity and soil functional diversity might possibly be due to the fact that higher values of plant richness and diversity result in a greater habitat heterogeneity in the soil, current knowledge on the topic is mixed and very incomplete and, then, one must be extremely cautious when interpreting such correlations.     

Application of amplified fragment length polymorphism markers to assess molecular polymorphisms in gynogenetic haploid embryos of turbot (Scophthalmus maximus)

Among the variety of cultured marine species, the turbot Scophthalmus maximus is a fish of growing importance in European aquaculture. In this paper, an advanced application of AFLPs to estimate the genetic diversity of haploid gynogenetic families with the aim of obtaining a preliminary genetic map is presented. Ten EcoRI/TaqI primer combinations were tested in four families comprising diploid mothers and their haploid progenies. The amplified fragment length polymorphism (AFLP) analysis revealed an average of 6.8 polymorphic bands per primer combination and a total number of 88 polymorphisms out of 579 fragments. Among various primer pairs, seven combinations were selected in relation to the quality of profiles and number of polymorphic fragments, to be used in the determination of genetic linkage relationship between AFLP markers within the largest haploid family. Co‐migration of non‐homologous fragments was also investigated in one primer combination adding a fourth selective nucleotide to the three used in the classic TaqI AFLP protocol. Surprisingly, a rate of 38.7% of non‐homologous fragments co‐migrating with monomorphic bands was identified, due to the combined effect of homoplasy and the protocol used. Additional polymorphic markers discovered by this protocol were included in the linkage map. The turbot AFLP linkage map comprises 52 AFLP markers distributed in 12 linkage groups. On the basis of this map, turbot expected total genome length sums up to 1225.6 cM. The results confirm the usefulness of AFLPs in revealing genome segregation in haploid turbot progeny.     

Changes in the lipid composition of powdered infant formulas during long-term storage

Changes in the lipid composition of two standard infant formulas induced by 4 years of storage were determined. Lipids were thoroughly analyzed using different gas-liquid and liquid-liquid chromatographic techniques. Oleic acid and linoleic acid, which accounted for almost the total monounsaturated and polyunsaturated fatty acids, respectively, showed slight but significant decreases (P < 0.05) during the 4 years of storage (from 41.52 to 39.83% for oleic acid and from 17.35 to 15.99% for linoleic acid). Total trans fatty acid isomers showed low initial level (0.22% of total fatty acids), and such level remained unchanged during the storage period. Nonvolatile oxidation compounds including oxidized, dimeric, and polymeric triglycerides did not significantly increase during the storage period, although a significant loss of tocopherols was found in the surface oil fraction (10-15%). In general, the results obtained indicate that, although small losses of oleic and linolenic acid as well as tocopherols were found, the 4 year storage period did not lead to relevant changes in the lipid fraction of infant formulas.     

Antimicrobial activity of coupled hydroxyanthracenones isolated from plants of the genus Karwinskia

The in vitro activity of some isolated hydroxyanthracenones belonging to the genus Karwinskia against four bacteria, six filamentous fungi and four yeast are reported. These hydroxyanthracenones were found to possess antimicrobial activity, particularly against Streptococcus pyogenes, Candida albicans, C. boidinii, C. glabrata and Cryptococcus neoformans; minimal inhibitory concentrations range between 16 and 2 microg/ml.     

Pore‐size distribution and particle arrangement in fragipan and nonfragipan horizons

Fragipan is a widely distributed subsoil horizon that induces severe limitations to plant growth and land use, mainly because of its high bulk density. In this work, we evaluated the pore‐size distribution through the analysis of the cumulative curve of intruded mercury volume in some soils with fragipan horizons. This approach provides information also about the arrangement of particles, thus we compared the results obtained for fragipan and nonfragipan horizons to relate porosity and particle arrangement with the specific physical properties of fragipans. The total volume of intruded mercury did not allow to discriminate between fragipan and nonfragipan horizons. However, from the variation of the pore volume as a function of the radius, two modal classes of pores were found, coarse and fine, respectively. The fine‐pore class arose from the arrangement of clay particles, and its volume was correlated to clay contents (r = 0.787) and to clay packing density (r = –0.621). The clay fractions in fragipans were less densely packed than in the other B horizons, even if they had similar clay contents. The coarser‐pore modal class is known to arise from the interactions between clay, silt, and sand particles, and its volume was different among horizons. Fragipan had a low volume of this modal pore class. In addition, a packing density for the coarser phase of 0.74, corresponding to a rhombohedral packing, was found only in fragipans. Thus, the low permeability and high bulk density of fragipans are linked to specific arrangements of the particles: an open packing of the clay phase is associated to an extremely dense packing of silt and sand. This combination is not present in any other soil horizon.     

Formation and evolution of monoepoxy fatty acids in thermoxidized olive and sunflower oils and quantitation in used frying oils from restaurants and fried-food outlets

The formation and evolution of monoepoxy fatty acids, arising from oleic and linoleic acids, were investigated in olive oil and conventional sunflower oil, representatives of monounsaturated and polyunsaturated oils, respectively, during thermoxidation at 180 degrees C for 5, 10, and 15 h. Six monoepoxy fatty acids, cis-9,10- and trans-9,10-epoxystearate, arising from oleic acid, and cis-9,10-, trans-9,10-, cis-12,13-, and trans-12,13-epoxyoleate, arising from linoleic acid, were analyzed by gas chromatography after oil derivatization to fatty acid methyl esters. Considerable amounts, ranging from 4.29 to 14.24 mg/g of oil in olive oil and from 5.10 to 9.44 mg/g of oil in sunflower oil, were found after the heating periods assayed. Results showed that the monoepoxides quantitated constituted a major group among the oxidized fatty acid monomers formed at high temperature. For similar levels of degradation, higher contents of the monoepoxides were found in olive oil than in sunflower oil. Ten used frying oils from restaurants and fried-food outlets in Spain were analyzed to determine the contents of the monoepoxides in real frying oil samples. Levels ranged from 3.37 to 14.42 mg/g of oil. Results show that, for similar degradation levels, the monoepoxides were more abundant in the monounsaturated oils than in the polyunsaturated oils.