Development of a semi-automatic system for pollen recognition

A semi-automatic system for pollen recognitionis studied for the european project ASTHMA. The goal of such a system is to provideaccurate pollen concentration measurements. This information can be used as well by thepalynologists, the clinicians or a forecastsystem to predict pollen dispersion. At first,our emphasis has been put on Cupressaceae, Olea, Poaceae and Urticaceae pollen types. The system is composed of two modules: pollengrain extraction and pollen grain recognition. In the first module, the pollen grains areobserved in light microscopy and are extractedautomatically from a pollen slide coloured withfuchsin and digitized in 3D. In the secondmodule, the pollen grain is analyzed forrecognition. To accomplish the recognition, itis necessary to work on 3D images and to usedetailed palynological knowledge. Thisknowledge describes the pollen types accordingto their main visible characteristerics and tothose which are important for recognition. Somepollen structures are identified like the porewith annulus in Poaceae, the reticulum in Oleaand similar pollen types or the cytoplasm inCupressaceae. The preliminary results show therecognition of some pollen types, likeUrticaceae or Poaceae or some groups of pollentypes, like reticulate group.     

A Kinetic Examination of Penicillin Acylase Stability in Water-organic Solvent Systems at Different Temperatures

We have studied the thermal stability of penicillin acylase from Streptomyces lavendulae in water-organic solvent monophasic systems at the range of temperatures between 40 and 60°C. We found a linear correlation between the log λP value of the solvent and the activation free energy for denaturation ( ΔG d ) at all temperatures tested. Thermodynamic analysis of the results indicates that solvents with log λP ≤-2.3 have protective effects, whereas solvents with log λP ≥-1.8 are deleterious for penicillin acylase.     

Estimation of coancestry in Iberian pigs using molecular markers

Genetic markers provide a useful tool toestimate pairwise coancestry betweenindividuals in the absence of a known pedigree. Inthe present work 62 pigs from two relatedstrains of Iberian breed, Guadyerbas andTorbiscal, belonging to a conservationprogramme with completely known pedigrees since1945, have been genotyped for 49microsatellites. Four coefficients thatsummarise molecular resemblance betweenindividuals together with eightestimators of coancestry have been calculatedfrom this information. Their values werecompared with the genealogical coancestry,calculated from the complete or partialpedigree. The eight estimations obtained usingmolecular information substantiallyunderestimate the coancestry calculated usingthe genealogical analysis. The correlationbetween the estimates and the genealogicalvalues was also calculated. This correlationwas high, between 0.78 and 0.93 for differentestimators, when all pairwise comparisons amongthe 62 animals were considered. However, thecorrelation decreases remarkably to 0.49–0.69and 0.37–0.47 for the Guadyerbas and Torbiscalpopulations respectively, when they wereanalysed separately. All the correlations weresimilar to those obtained when using simplecoefficients of molecular resemblance such asmolecular coancestry or similarity indexes.Finally, simulations were carried out tofurther explore the results obtained. It isconcluded that lack of information on theallele frequencies in the base population mayexplain the bias of these estimators inpopulations with complex pedigrees.     

Non-peptide alpha(v)beta(3) antagonists. Part 3: identification of potent RGD mimetics incorporating novel beta-amino acids as aspartic acid replacements.

Potent non-peptidic alpha(v)beta(3) antagonists have been prepared incorporating various beta-amino acids as aspartic acid mimetics. Modification of the beta-alanine 3-substituents alters the potency and physicochemical properties of these receptor antagonists and in some cases provides orally bioavailable alpha(v)beta(3) inhibitors.     

Test for positional candidate genes for body composition on pig chromosome 6

One QTL affecting backfat thickness (BF), intramuscular fat content (IMF) and eye muscle area (MA) was previously localized on porcine chromosome 6 in an F₂ cross between Iberian and Landrace pigs. This work was done to study the effect of two positional candidate genes on these traits: H-FABP and LEPR genes. The QTL mapping analysis was repeated with a regression method using genotypes for seven microsatellites and two PCR-RFLPs in the H-FABP and LEPR genes. H-FABP and LEPR genes were located at 85.4 and 107 cM respectively, by linkage analysis. The effects of the candidate gene polymorphisms were analyzed in two ways. When an animal model was fitted, both genes showed significant effects on fatness traits, the H-FABP polymorphism showed significant effects on IMF and MA, and the LEPR polymorphism on BF and IMF. But when the candidate gene effect was included in a QTL regression analysis these associations were not observed, suggesting that they must not be the causal mutations responsible for the effects found. Differences in the results of both analyses showed the inadequacy of the animal model approach for the evaluation of positional candidate genes in populations with linkage disequilibrium, when the probabilities of the parental origin of the QTL alleles are not included in the model.     

Enzymatic conversions of polar lipids. Principles, problems and solutions

This text provides a brief overview of the principles of enzymatic lipid conversion and some recent advances in the enzymatic conversion of glycerophospholipids and galactolipids. Lipases and phospholipases are used to exchange fatty acids or the polar group in the lipids. The reactions can be carried out either as hydrolysis–esterification sequences or as one-step transferase reactions. The scope and limitations of the different methods are discussed.     

Strategies for genetic conservation of trees in the Peruvian Amazon

Forestry practices and high rates of land clearance for agriculture are causing genetic erosion of valuable tree species in the Peruvian Amazon, thereby endangering the economic sustainability of rural communities and limiting Peru's opportunities for the development of new timber and non-timber forest products. The potential utility and limitations of six low-input interventions to help forestall further genetic erosion in the region are discussed, with a focus on local community involvement. Improved agroforestry systems may help reduce deforestation by increasing farm productivity, although methods to increase the currently low adoption rate of these technologies need to be developed. Use of strategic tree domestication techniques can also improve farm productivity and prevent inadvertent genetic drift and inbreeding associated with traditional domestication practices, although to have a major impact, current programs need to be extended across the region. Woodlot forestry could supplant selective extraction of timber and offers an attractive opportunity for poverty alleviation if appropriate credit and land tenure policies can be developed. However, it may also result in increased deforestation if activities on public land cannot be controlled. The implementation of improved seed collection systems and simple seed transfer guidelines would help to reduce the collection of seed of poor quality and low genetic diversity, and avoid maladapted plantings, although such programs are difficult to monitor and seed costs may increase. Strategic identification and design of in situ conservation areas would help to ensure the viability of conserved populations, but requires the forfeiture of significant revenue from timber concessions.     

Chemotactic activity of pertussis toxin on murine lymphocytes. Its potential role on lymphocyte accumulation in the lung

Abstract The effects of pertussis toxin on lymphocyte migration were studied in vitro. In this study pertussis toxin significantly stimulated lymphocyte migration at concentrations of 0.1 and 1 μg ml⁻¹ using a microchamber and the leading-front method. Checkerboard analysis demonstrated that pertussis toxin causes directed migration of lymphocytes (chemotaxis). Heat-treatment of pertussis toxin abolished its capacity to cause this migration. When murine lymphocytes were preincubated with different concentrations of pertussis toxin, an inhibition of chemotaxis at the dosages of 0.1 and 1 μg ml⁻¹ was observed. On the other hand, lymphocytes derived from mice treated with pertussis toxin were not inhibited after subsequent exposure to pertussis toxin in vitro. Since lymphocyte accumulation in the lungs of mice treated with pertussis toxin has been well domenstrated, the results of our study could suggest a chemotactic activity of pertussis toxin in determining accumulation of lymphocytes in this organ.